David Palacios
email: davidp@ucm.es

Jesus Ruiz-Fernández

Marc Oliva

Nuria Andrés

José M Fernández-Fernández

Irene Schimmelpfennig

Laettitia Léanni

Benjamín González-Díaz

Team Aster

Nuria De Andrés

D E Pablo

Laetitia Leanni

Didier Bourlès

Stephen Roberts

Daniel Nývlt

Vincent Jomelli

Brenda Hall

Michael Bentley

Laëtitia Leanni

Aster Team

Timing of formation of neoglacial landforms in the South Shetland Islands (Antarctic Peninsula): Regional and global implications

Keywords: Antarctic Peninsula, Byers Peninsula, Neoglaciation, surface exposure dating, Antarctic Peninsula, Byers Peninsula, Neoglaciation, surface exposure dating

établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Submission Files Included in this PDF File Name [File Type]

Cover_letter.docx [Cover Letter] ANSWER TO Highlights.docx [Highlights] MANUSCRIPT NEOGL Table 1-R.docx [Table] Table 2 F.docx [Table] Table 3 F.docx [Table] Table 4 F.doc [Table ]   Table 5 F.docx [Table] Table 6 F.docx [Table] Table 7-R.docx [Table] declaration-of-competing-interests. We present an unpublished work entitled " Timing of formation of neoglacial landforms in the South Shetland Islands (Antarctic Peninsula): regional and global implications", which focused on the Neoglacial landforms in the Antarctic Peninsula. The work makes an exhaustive bibliographical revision of the dating of Neoglacial landforms in this region and chooses an area of ideal experimentation, in the Byers Peninsula and finds multiple possibilities in the cosmogenic method to apply in the future. We think that the research and its relevance fits well with the scope of the journal Quaternary Science Research.

In addition to our analysis, our manuscript presents a dataset of 12 samples, important and a novel revision on the state of knowledge of the Neoglaciation en the Antarctica. In this sense, the limited number of samples is compensated with a detailed previous study, analyzing the degree of stability of the sampled boulders, by combining other methods, which is a completely new strategy.

The work deals with the problem of Neoglacial landforms, using Cosmic-Ray Exposure (CRE) dating, which is still in its initial phase, and analyzes all the problems that can be encountered, such as inheritance, reception of cosmic radiation during boulder transport, etc. On the other hand, it addresses the geomorphological and climatic significance that the formation of Neoglacial advances in the context of Holocene climate tendency. It should be noted that this is the first time that these methods are applied Neoglacial landforms in this area.

We believe that the manuscript provides a strong bibliographic review and opens new paths to research on climatic and geomorphological evolution in Neoglacial landforms.

All the authors have worked with intensity in the investigation, whose results are presented:

1. David Palacios, coordination of the whole phases of the research and draft of a first manuscript, sampling and intense geomorphological fieldwork and data processing and collaboration in the writing 2. Jesus Ruiz-Fernández. sampling and intense geomorphological fieldwork and data processing and collaboration in the writing 3. Marc Oliva, sampling and intense geomorphological fieldwork and data processing and collaboration in the writing 4. Nuria Andrés, data processing and geomorphological cartography and collaboration in the writing.

5. José M. Fernández-Fernández. Work in the laboratory and data processing and geomorphological cartography and collaboration in the writing.

6. Irene Schimmelpfennig. Supervision of the whole process of analysis of the samples and interpretation of the results. Exhaustive correction of the manuscript 7. Laetitia Leanni. Work in the laboratory and treatment of cosmogenic data, correction of the manuscript.

-Reviewer 2-

In their paper, "Timing of formation of neoglacial landforms in the South Shetland Islands (Antarctic Peninsula): regional and global implications", Palacios et al. present a study of neoglacial landforms and related chronology, by means of cosmogenic ray exposure, of a sector of the Livingstone Island. The presented information, mainly the chronology, is of particular interest, however the manuscript fails in some respects.

We appreciate the suggestions made by reviewer 2, which we have tried to follow in all cases and believe that they have helped to improve the manuscript.

Firstly, the text has a poor grammatical writing, several sentences show grammatical mistakes, redundancies and/or are not comprehensible

We have reviewed and improved the entire wording of the text, with the help of professional, expert in English and with expertise in geosciences.

(Just some examples: lines 41-44,

We have changed and improved the wording of these sentences. See lines 28-40.

120-122,

We have eliminated this sentence, as it was too general and obvious.

237-240,

We have now explained it better in the new text. Lines: 222-235.

249-252,

We have now explained it better in the new text. Lines: 250-253.

261-262,

We have corrected the mistakes.

280-282,

We have eliminated this sentence as it was confusing.

333-337,

We have now explained it better in the new text. Lines: 330.

678-679,

We have now explained it better in the new text. Lines: from 662.

734-736,

We have improved the writing. See Lines: from 793.

758-761,

We have improved the writing. See Lines: from 793.

¨characterized the Antarctic during …¨ at line 63, study case (?) at line 117 and 422 (case study in Abstract and other sections),

We have reviewed and corrected this erratum throughout the text. line 678: using ¨proposed¨ 4 times in one paragraph (9 lines), among others.

We have changed the text with more variety of synonym verbs. See Lines: from 793.

It is not clear the sentence (the last one of the abstract) ¨These results support the idea that Neoglaciation is driven by global climate forcing, unlike other Holocene glacial advances that are specific to each hemisphere.¨ What do they refer with ¨other Holocene glacial advances¨? Not Neoglaciation?

We agree with the reviewer, who also makes the same observations of Prof. Jomelli. We have changed this sentence and eliminated the general and confusing statements. See lines 840-857.

When few lines after they quote ¨the term Neoglaciation to refer to the glacial advances that occurred after the Holocene Thermal Maximum (HTM: 11-5 ka, [START_REF] Renssen | The spatial and temporal complexity of the Holocene thermal maximum[END_REF] until the end of the Little Ice Age (LIA).¨ ???? Moreover, in the abstract the authors indicate their research ¨These results support the idea that Neoglaciation is driven by global climate forcing …¨ but they do not describe, discuss, assess nothing of their results in relation to that topic in any part of the text.

We only wanted to delimit what is called Neoglaciation period according to the scientific literature.

The result of our contrast between the glacial advances along the Late Holocene in the Antarctic Peninsula and in the Arctic confirm that these processes occur simultaneously in the high latitudes of both hemispheres. The causes of climatic mechanisms driving this synchronicity in glacial advances in both polar areas are out of our expertise, and should be responded by paleoclimatologists. However, we have included now the most outstanding paleoclimatic findings about this subject at the end of the discussion. See lines 840-957.

The manuscript is untidy in some aspect, for example there is not section 3, it passes from section 2 (line 124) to section 4 (line 352), and in between there is subsection 3.3 (!).

Yes, it was a mistake and it is already corrected.

In general, the text of the Introduction is confused.

The other reviewers think also the same. We have changed and rewritten the most confusing sections of the introduction and we believe that now the objectives of the work and their context are now well understood. See lines 98-110.

The Methodology section only explains the laboratory aspect of the dating by cosmogenic ray exposure, but it lacks information about the geomorphological survey and a general description of how the sampling strategy was designed and what this strategy represents.

We agree with the reviewer and have added a new section to the methodology, where the geomorphological strategy is clearly exposed. See lines from 423.

Other significant weakness is the lack of a geomorphological map. Considering the authors are using glacial landforms to find evidences and reconstruct neoglacial advances, and they sample boulders and surfaces of these glacial landforms, it is essential to elavorate a map with the detailed geomorphology of the study area and location of samples in that map to allow the readers to understand and evaluate the obtained information.

We agree with the reviewer and have included a new figure with the geomorphological map, where you can see all the landforms cited in the text and help to understand the results. See lines from 589 and new figures 5 and 6.

Besides, when one read the section of results ¨6.1 Geomorphological setting of neoglacial landforms¨ it is not clear what results are own from the authors and which ones are from other authors. In the first sentence they say ¨Outside the moraine system next to Rotch Dome glacier, there are no clear moraine formations that would correspond to Late Holocene advances¨ but it is not clearly explained the basis for that assumption.

Again, we agree with the reviewer and have left only our results in that section. See lines from 589.

In some sentences the authors describe results using comparative adjectives but without including with what other element they are comparing. In line 595 it is not clear what ¨the last surface¨ means.

We have improved the writing and we have located the samples on the geomorphological map and in figure 4, 5 and 6, as requested by the reviewer 1, so that now the explanation is much better understood.

Finally, I consider the author can find a briefer and more comprehensible way to synthesize the state of knowledge on the Neoglaciation. The section ¨2. State of knowledge of the Neoglaciation chronology in South Shetland Islands in the context of the Antarctic Peninsula¨ is very long and confused. The previously published data is already in the tables, then I suggest producing a shorter text about this topic and to produce some kind of figure or table to summarize the conclusions.

We have summarized and improved the wording throughout that section. We have also included the requested figure, which helps to compare our results. See lines from 134.

Figures: I do not see the necessity of including the figure 1, it is enough the maps of figure 2 to put in context the case study. But I highly recommend including a detailed geomorphological map of the study area, with the sample dots. In figure 3 it is recommend adding more information of each sample besides the lab code.

According to reviewer 3, we keep Figure 1, with the location of all the place-names cited in the text. But we have simplified Figure 2 and it is no longer repetitive with Figure 1. We have also expanded the information requested in Figure 3.

-Reviewer 3 (Jan-Hendrik May)

The manuscript "Timing of formation of neoglacial landforms in the South Shetland Islands (Antarctic Peninsula): regional and global implications" presents a comprehensive review of studies investigating climatic and landscape changes around Antarctica with focus on the Antarctic Peninsula. It also presents a new dataset of cosmogenic surface exposure dates from the South Shetland Islands and discusses the results within the framework of the existing literature. The topic and approach are well in line with the scope of QSR. The paper is of very reasonable length and I have very much enjoyed reading it -it is well written and presented and follows a clear and logical structure. In addition, all figures are of top quality and contribute in providing a context for the new dataset. Therefore, I believe that the paper deserves publication after addressing a few general and more specific minor issues and suggestions that I will list in the following:

We are very grateful to Prof. May for each and every one of his indications. We have corrected all the errors indicated and have followed the majority of his advices, improving considerably the manuscript.

Some general issues and suggestions:

1. Could you discuss the local-scale controls on glaciers and glacial advances (e.g. temp vs precipitation) a bit more somewhere -this may help to highlight the scope of your study and research. Are you interested in glaciers as a temperature proxy -or are you interested in the evolution of Antarctic landscapes?

Unfortunately, there are not many quantitative or qualitative climate records from the Antarctic Peninsula for the last millennia. Several researchers are working now to provide quantitative reconstructions of past temperature conditions using lake (e.g. BAS researchers, Dr. Hodgson, Dr. Roberts) and marine records (Dr. Etorneau) to produce such reconstructions. We have included in the discussion some references related to the Neoglacial period to support the text. See lines from 791. We have really followed the reviewer's advice, and we have cited the latest reflections of paleoclimatologists on this topic at the end of the discussion. We consider that is important to take these ideas into consideration to correctly frame our results. See lines 848-056.

3. The geomorphological setting of neoglacial landforms is part of the results but there is no methodology section corresponding to these results -add some info on how the mapping / field work was done…

We agree with the reviewer (reviewer 2 mentioned the same), and have added a new section to the methodology, where the geomorphological strategy is exposed. See lines from 423.

4. In your literature review provide errors for cited ages where possible or indicate the uncertainties by adding "~"

We have followed this suggestion whenever we have been able to agree with the information provided by the publications.

5.Literature review and Fig. 1 -The literature review seems solid and rather complete but -due to the large number of cited studies -can be somewhat difficult to keep track of while reading.

Could you include the localities of these studies into your overview figures 1 and 2 (and providing reference in the figure captions)? This would graphically add to the review, and help the reader to assess the relevance of the individual records with regard to your results.

We have completed the Figure 1 with the location of all the place-names cited in the text. But we have simplified Figure 2 and it is no longer repetitive with Figure 1.

6. I agree with the subdivision of the review into archives (i.e. ice cores, marine sediments etc). For many of these cited studies and their results, however, it might make sense to add some info on which proxies these study use (e.g. are the results based on isotopes, or sedimentation rates, or …) to avoid comparing "apples with oranges"? And, what do the proxies us and how do they inform on past climate?

We have followed the instructions of the reviewer and at the beginning of each paleoclimatic source we have made a minimum summary. Obviously each method is very complicated to explain and a lot of text would be necessary. In the new version of the text, we believe that with the small introduction the reader can assess the meaning of the ages proposed by each proxy. See lines from 137.

Specific minor comments:

The abstract is well written but includes some detailed place names (e.g. line 25-29 -Livingston Island, Rotch Dome, Clark Nunatak) and detailed information (e.g. lines 32-38 -is it necessary to provide sample numbers and specific elevations here?) that -at least in my opinion -are distracting from the main idea and results of the paper. Consider summarizing these details and thereby shortening the abstract.

This suggestion coincides with that from Prof. Jomelli. We have deleted unnecessary information for the summary, shortening it. See lines 28-40

Line 30 -basalt rocks Done.

Lines 45 -you refer to the hemispheric scale here, but from my understanding some glacial advances are also specific to even more regional or local scales… Consider adding: "specific to a region or hemisphere"

We have changed this whole sentence and have included your idea. You can see a much clearer wording in the new sentence. Lines: 28-40. Line 448-450 -How was the compositional analysis done? XRF? ICMPS? Specify somewhere

The analysis performed is specified in the following paragraphs. See Lines: from 483-487.

Line 466-468 -is the final step of oven drying also resulting in targets (similar to the 10Be approach)?

NO. We have clarified it in the text with a new sentence. See lines 503-505.

Line 492 -could you briefly add a comment as to why the 35Cl/37Cl ratio is important to consider for this method!?

We have now rewritten the earlier sentence to clarify this aspect. Line 580 -so, these boulders are (partly?) embedded in sediment, and you interpret them to be ice-rafted? Could you provide some brief explanation how this process works -mainly to justify the boulders' use for exposure dating…

The position of these boulders with respect to the beaches is defined in the previous paragraphs.

We have added a phrase where, at the request of the reviewer, we present our hypothesis about the meaning that the results of their dating by cosmogenic methods can mean, since there is no previous experience. Line 731 -nature of the records and dating methods. Yes, I agree, but I think these statements need some more commenting and discussion somewhere.

We agree with reviewer's comments. Due to limited space in this work, we have included a limited explanation and given some examples of the progress that is being made recently to homogenize the results of each method and make them comparable. See new wording in Lines: from 792.

Line 725-770 -ok to relate your results to the existing results around the AP, but before discussing the global significance and comparing with Arctic records, wouldn't it make sense to compare it against the wider context of the entire Antarctic continent?

Yes, we agree. In fact, we have included the most important references about Neoglaciation from the rest of Antarctica. In any case, the comparative sectors of the Arctic have a greater climatic similarity (temperate and humid) and similar glacial variability with the Antarctic Peninsula than the rest of most continental Antarctica. We agree with reviewer's observation. That is why we have added several phrases that clarify it in the introduction, in the study area and we have adapted the aforementioned text to the problem previously described. See Lines: See Line: 860.

Line 777-the evolution.. of what? Mid-Late Holocene Now it is clarified in the text. See Lines: See Line: 864.

Line 790-791 -add a brief comment on potential reasons for this regional diversity and discrepancies here

The explanation of the causes of this diversity in the Arctic is a very complex and debatable problem, which would require a much more detailed analysis of the literature, which exceeds the objectives of this work. In any case, we have followed the reviewer's suggestion and summarized it in one sentence the basic and obvious fact of that diversity. See Lines: 879-800.

References list -check Lifton reference!!

We have corrected the reference. See Line: 1200.

these surfaces. The CRE dates indicate that the onset of deglaciation started around 9.9 ± 1.2 ka, with two phases of glacier expansion during the Mid-Late Holocene forming moraines at ~4.1 ± 0.5 and ~1.0 ± 0.2 ka, respectively. The main neoglacial advances in the AP and the SSI were mostly synchronous and coincided with cold periods, as shown by other records (e.g. glacio-isostatic marine terraces, marine and lake sediments). In addition, these periods of glacial expansion show a similar timing to those recorded in the Arctic. These results suggest that Neoglaciation was driven by global climate forcing in both polar areas despite temporal variations at regional and local scale.

Introduction

The Antarctic Peninsula (AP; Fig. 1) is affected by intense warming, which is recorded through reliable meteorological measurements since approximately 1950. This most recent period has been called Recent Rapid Warming (RRW), and is characterized by an accelerated temperature increase being four times greater in the AP region than the Earth's average [START_REF] Vaughan | Recent rapid regional climate warming on the Antarctic Peninsula[END_REF][START_REF] Turner | Antarctic climate change during the last 50 years[END_REF]. This dramatic temperature rise caused fast melting of glaciers and a generalized retreat of glacier fronts [START_REF] Vaughan | Recent atmospheric warming and retreat of ice shelves on the Antarctic Peninsula[END_REF][START_REF] Cook | Retreating glacier fronts on the Antarctic Peninsula over the past half-century[END_REF][START_REF] Kunz | Multi-Decadal Glacier Surface Lowering in the Antarctic Peninsula[END_REF][START_REF] Pritchard | Antarctic ice-sheet loss driven by basal melting of ice shelves[END_REF]. However, since 1998 a tendency towards cooling in the AP and a return to positive mass glacial balances has been detected [START_REF] Navarro | Decelerated mass loss of Hurd and Johnsons Glaciers, Livingston Island, Antarctic Peninsula[END_REF][START_REF] Engel | Surface Mass Balance of Small Glaciers on James Ross Island, North-Eastern Antarctic Peninsula, during 2009-2015[END_REF]. This shift is associated with an increase in the frequency of low pressure systems that has led higher precipitation and lower summer temperatures in the region, particularly in the N and NE AP region, including the South Shetland Islands (SSI) [START_REF] Turner | Absence of 21st century warming on Antarctic Peninsula consistent with natural variability[END_REF][START_REF] Sancho | Recent warming and cooling in the Antarctic Peninsula region has rapid and large effects on lichen vegetation[END_REF]Oliva et al., 2017a) (Fig. 2). Therefore, the question arises whether RRW is the beginning of a trend towards deglaciation in the AP, or a brief warming within the longterm cooling trend affecting this region over the last millennia, continuation of the longterm cooling started since the Neoglaciation [START_REF] Vaughan | Recent rapid regional climate warming on the Antarctic Peninsula[END_REF]Bentley et al., 2009).

However, the timing, distribution, evolution and origin of the neoglacial advances in the AP region is still poorly understood because of: (i) the lack of historical information on this continent, (ii) the limited number of terrestrial natural archives as sources of palaeoenvironmental information, and (iii) the difficulties of dating these glacial advances in Antarctica [START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF]. [START_REF] Porter | Chronology of the neoglaciation in the North American cordillera[END_REF] proposed the generalization of the term Neoglaciation to refer to the glacial advances that occurred after the Holocene Thermal Maximum (HTM: 11-5 ka, [START_REF] Renssen | The spatial and temporal complexity of the Holocene thermal maximum[END_REF] until the end of the Little Ice Age (LIA). Evidence of Late Holocene glacial advances has been found in a great variety of latitudes and continents [START_REF] Solomina | Holocene glacier fluctuations[END_REF], widespread also in mountains of the Southern Hemisphere [START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF][START_REF] Porter | Onset of neoglaciation in the Southern Hemisphere[END_REF] and Antarctica [START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF]Clapperton et al., 1989;[START_REF] Ingólfsson | Antarctic glacial history since the Last Glacial Maximum: an overview of the record on land[END_REF]. However, delimiting the end of the HTM and the onset of the neoglacial chronology in the Polar Regions is a matter of great complexity [START_REF] Kaufman | Holocene thermal maximum in the western Arctic (0-180 W)[END_REF][START_REF] Renssen | The spatial and temporal complexity of the Holocene thermal maximum[END_REF][START_REF] Renssen | Global characterization of the Holocene thermal maximum[END_REF]. Similarly, the concept of Neoglaciation in the Arctic has been proposed as a tendency to climate cooling [START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF]. However, phases of glacial advances in the Arctic during Neoglaciation alternated with warm periods and glacial retreat, occurring asynchronously across the region without a clear regional pattern [START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF].

As in the Arctic, the chronology of Neoglaciation varied significantly within the AP and throughout the Antarctic continent (Bentley and Hodgson, 2009). According to the available glacio-marine sedimentary records, cold phases during Neoglaciation in the AP region were short, not exceeding 0.5 ka [START_REF] Yoon | Late Holocene cyclic glaciomarine sedimentation in a subpolar fjord of the South Shetland Islands, Antarctica, and its paleoceanographic significance: sedimentological, geochemical, and paleontological evidence[END_REF], and alternated with longer warm periods [START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF]. The first synthesis on climatic and glacial evolution in the AP during the Holocene was carried out by [START_REF] Ingólfsson | Antarctic glacial history since the Last Glacial Maximum: an overview of the record on land[END_REF] who suggested the first neoglacial advances after 5 ka. [START_REF] Ingólfsson | Glacial and climate history of the Antarctic Peninsula since the Last Glacial Maximum[END_REF] proposed several other neoglacial advances between 3 and 1 cal ka BP. Bentley et al. (2009[START_REF] Bentley | A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum[END_REF] reported a generalized warm period in the AP between 4.5 and 2.8 cal ka BP followed by a relatively widespread cold period between 2.5 and 1.2 cal ka BP. Bentley and Hodgson (2009) highlighted that Late Holocene cold phases in different sites across the AP were not synchronous, even in close regions. [START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF] provided a synthesis of Holocene glacial evolution for the entire Antarctic continent, including the AP, with many references to neoglacial landforms. Subsequent studies provided new glacial evidence of neoglacial landforms in other regions, thus confirming the occurrence of the Neoglaciation as a widespread pattern of glacial advance in the AP [START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Davies | Landscape evolution and ice-sheet behaviour in a semi-arid polar environment: James Ross Island, NE Antarctic Peninsula[END_REF]Carrivick et al., 2012;[START_REF] Cofaigh | Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum[END_REF]. However, these new data also introduce new uncertainties about the time range of neoglacial phases in different areas across this region [START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF][START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF][START_REF] Cofaigh | Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum[END_REF]. The spatiotemporal variations of glacial oscillations over the last centuries are also a consequence of climate variability in the region [START_REF] Mosley-Thompson | Little ice age (neoglacial) paleoenvironmental conditions at siple station, Antarctica[END_REF][START_REF] Guglielmin | Glacial fluctuations since the 'Medieval warm period'at Rothera Point (western Antarctic Peninsula)[END_REF][START_REF] Brightley | A Paleoclimate Reconstruction of the Little Ice Age to Modern Era Climate Conditions in the Eastern Ross Sea, Antarctica as Captured in the RICE Ice Core[END_REF]. Recently, Čejka et al. (2019) examined the neoglacial onset in the AP region through the revision of 22 studies focused on ice cores and marine and lake sediments. They concluded that the beginning of neoglacial cooling occurred, in average, at 2.6 ± 0.8 cal ka BP, with large spatio-temporal differences within the AP region ranging between 4.8 ka and 1.2 cal ka BP. However, a review on glacier oscillations during Neoglaciation is still missing. [START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF] provided new information about the Neoglaciation chronology in the AP and compared it with the neoglacial advances in Patagonia.

The Byers Peninsula, on the western end of Livingston Island, is the largest deglaciated terrestrial area in the SSI (Fig. 2). In this area, lake records suggest that the retreat of the Rotch Dome Glacier occurred throughout the Holocene [START_REF] Toro | Chronostratigraphy of the sedimentary record of Limnopolar Lake, Byers Peninsula, Livingston Island, Antarctica[END_REF][START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF]Ruiz-Fernández and Oliva, 2016), although the existence of neoglacial landforms, such as moraines, is not yet evidenced. The application of cosmogenic radiation exposure (CRE) methods -that have not been applied yet to neoglacial landforms in the SSIoffers new possibilities to obtain a detailed chronology for the development of these neoglacial landforms. The knowledge of the age of moraines formed in neoglacial advances in the Byers Peninsula can provide important information on the possible synchrony of these advances within the context of the AP.

The aim of this paper is to map and date neoglacial landforms in the SSI as well as explore their paleoclimatic implications in the context of the Antarctic continent. Firstly, we review the current state of knowledge of Neoglaciation in Antarctica, focusing mainly in the AP. In order to provide the most detailed picture on the paleoclimatic evolution in this region, we examined all available records from ice cores, deep marine sediment cores, lake sediments and glacial landforms. Subsequently, we focused on an area of the AP region where information about Holocene glacial advances is still absent: the Byers Peninsula. In this peninsula, we have mapped the spatial distribution of possible neoglacial moraines, analyzed the geomorphological setting, and applied CRE dating to these landforms.

The Neoglaciation in the Antarctic Peninsula and South Shetland Islands

A recent synthesis of the evolution of the West and East Antarctic Ice Sheets shows that glacial mass loss was intense from 9 until 7-6 ka in both areas [START_REF] Mackintosh | Retreat of the East Antarctic ice sheet during the last glacial termination[END_REF][START_REF] Mackintosh | Retreat history of the East Antarctic Ice Sheet since the last glacial maximum[END_REF], mainly due to ocean warming, although the long-term glacial shrinking had already begun before 10 ka [START_REF] Larter | Reconstruction of changes in the Amundsen Sea and Bellingshausen sea sector of the West Antarctic ice sheet since the last glacial maximum[END_REF]. (Fig. 1, Table 1). A wide range of climatic proxies provides data on the occurrence of various cold periods in the AP for the last millennia.

In order to constrain the magnitude and the chronology of neoglacial advances and retreats in the SSI, we first review the climatic evolution over the Mid-and Late Holocene in the AP region based on different environmental sources:

(i) Neoglaciation from ice cores in the AP. Polar ice cores preserve and provide information on climatic changes and their causes, mainly from comparison of the δ 18 0, deuterium and CO 2 concentration variations in different layers, as well as on the climate and chronology from the impurities of the ice [START_REF] Lorius | The ice-core record: climate sensitivity and future greenhouse warming[END_REF]. The most accurate reconstruction from ice core records in the AP comes from James Ross Island, NE AP, which revealed a cold phase between 2.5 and 0.6 cal ka BP, and a peak of cold climate that occurred roughly at 1.4 cal ka BP [START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Abram | Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century[END_REF]. The last phase of intense cooling was recorded during the LIA at around AD ~1410-1460 [START_REF] Abram | Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century[END_REF], as also detected in ice cores from other areas in Antarctica, e.g. Ross Sea, with a temperature ca. 2º C colder than present [START_REF] Bertler | Cold conditions in Antarctica during the Little Ice Age e implications for abrupt climate change mechanisms[END_REF], or in Princess Elizabeth Land, East Antarctica, with a significant cooling at AD 1450-1850 [START_REF] Li | Glaciochemical evidence in an East Antarctica ice core of a recent (AD 1450-1850) neoglacial episode[END_REF] (Fig. 1 and Table 1).

(ii) Neoglaciation from marine sediments in the AP. Deep marine sediment cores can reveal climatic changes based on the proportion of foraminifera and microfossils that are highly sensitive to sea surface temperatures. The ratio of the oxygen isotopes from the calcium carbonate shells of foraminifera and coccoliths, and from the silicon dioxide shells of radiolarians and diatoms, is indicative of the temperature of the ocean during the build-up of every shell layer [START_REF] Rothwell | New techniques in sediment core analysis: an introduction[END_REF]. Several sedimentary records were collected from areas adjacent to the AP region. As in ice core records, most records show changes in sedimentation patterns during neoglacial cold periods , with notable chronological differences. Records obtained in the Bransfield Strait reported abrupt cold conditions at 4.5 and 2.5 cal ka BP [START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF], at 3.5 and 1.2 cal ka BP [START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Heroy | Holocene climate change in the Bransfield Basin, Antarctic Peninsula: evidence from sediment and diatom analysis[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF] and during the LIA [START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF]. In other records from the western side of the AP, similar patterns were observed, including long-term cooling trends from 3.3 to 0.1 cal ka BP in Palmer Deep [START_REF] Domack | Chronology of the Palmer Deep site, Antarctic Peninsula: A Holocene palaeoenvironmental reference for the circum-Antarctic[END_REF], from 2.8 to 0.2 cal ka BP in Marguerite Bay [START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF], and during the LIA in Müller Ice Shelf [START_REF] Domack | Late Holocene advance of Müller Ice Shelf, Antarctic Peninsula: sedimentological, geochemical, and palaeontological evidence[END_REF] and in Barilari Bay, Graham Land [START_REF] Christ | Late Holocene glacial advance and ice shelf growth in Barilari Bay, Graham Land, west Antarctic Peninsula[END_REF][START_REF] Reilly | Holocene glacial activity in Barilari Bay, west Antarctic Peninsula, tracked by magnetic mineral assemblages: Linking ice, ocean, and atmosphere[END_REF]. Neoglacial cooling was also reported in the NE of the AP, as in the Firth of Tay, where marine sediment cores revealed a minor glacial advance between 6.0 and 4.5 cal ka BP, retreat between 4.5 and 3.5 cal ka BP, and glacial readvance from 3.5 cal ka BP to recent times [START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF] (Fig. 1 and Table 1).

(iii) Neoglaciation from lake sediments in the AP. Paleolimnological studies can reveal climatic changes from a wide range of proxies including the analysis of magnetic susceptibility, grain-size distribution, geochemistry, diatoms studies, and geochronology [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF][START_REF] Čejka | Timing of the Neoglacial onset on the north-eastern Antarctic Peninsula based on lacustrine archive from Lake Anónima, Vega Island[END_REF]. Čejka et al. (2019) examined the onset of Neoglaciation in the AP region from lacustrine sediments suggesting that it occurred at 2 cal ka BP, with significant regional variations. Conversely, in our study, we analyzed periods during the Neoglaciation that led to glacial advances. Evidences of neoglacial advances in the AP from lacustrine sediments suggest a phase of glacial expansion at 1.2 cal ka BP in James Ross Island, (Björck et al., 1996a), at around 5 ka and during the LIA in Hope Bay [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF]) and from 2.6 until 1.1 cal ka BP in Marguerite Bay [START_REF] Hodgson | Late Quaternary environmental changes in Marguerite Bay, Antarctic Peninsula, inferred from lake sediments and raised beaches[END_REF] (Fig. 1 and Table 1).

(iv) Neoglaciation from raised beaches in the AP. Rates of glacio-isostatic uplift inferred from the elevation of raised beaches are indicative of the intensity of the deglaciation [START_REF] Simkins | Relative sea-level history of Marguerite Bay, Antarctic Peninsula derived from optically stimulated luminescence-dated beach cobbles[END_REF]. [START_REF] Hall | New relative sea-level curves for the southern Scott Coast, Antarctica: evidence for Holocene deglaciation of the western Ross Sea[END_REF] determined that these rates were especially high between 8 and 5 cal ka BP in the Ross Sea, suggesting that glacial shrinking decreased during the Mid Holocene. However, decreasing uplift rates can be also indicative of glacial advances [START_REF] Simkins | Relative sea-level history of Marguerite Bay, Antarctic Peninsula derived from optically stimulated luminescence-dated beach cobbles[END_REF]. In Beak Island, NE AP, the relative sea level fell from a maximum uplift rate of 3.91 mm yr -1 at around 8 cal ka BP to 2.11 mm yr -1 between 6.9 and 2.9 cal ka BP, 1.63 mm yr -1 between 2.9 and 1.8 cal ka BP, and finally to 0.29 mm yr -1 during the last 1.8 ka BP. This reveals a trend towards more glacial stability and/or glacial readvances during the neoglacial period [START_REF] Roberts | Geological constraints on glacio-isostatic adjustment models of relative sea-level change during deglaciation of Prince Gustav Channel[END_REF] (Fig. 1 and Table 1).

(v) Neoglaciation from glacial landforms in the AP. Together with these proxies, some studies have focused on the direct dating of neoglacial landforms in the AP. Radiocarbon dating of unconsolidated glacial sediments demonstrated the occurrence of six neoglacial advances at 6.5, 4.6, 3.9 cal ka BP, two around 2.6 cal ka BP, as well as glacial expansion during the LIA in James Ross Island [START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF]. This LIA glacial advance has been also detected in the western AP, namely in Rothera Point, Marguerite Bay [START_REF] Guglielmin | Glacial fluctuations since the 'Medieval warm period'at Rothera Point (western Antarctic Peninsula)[END_REF] as well as in Anvers Island, where the glacier front was at or behind its present position at 0.7-0.9 cal ka BP [START_REF] Hall | Reduced ice extent on the western Antarctic Peninsula at 700-970 cal. yr BP[END_REF] (Fig. 1 and Table 1).

Outside the AP, in the Scott Coast, in Ross Sea, Late Holocene moraines are distributed on dated raised beaches indicating a neoglacial advance that occurred between 3.5 ka and the LIA [START_REF] Hall | Holocene history of the Wilson Piedmont Glacier along the southern Scott Coast[END_REF].

However, the most reliable approach to date Neoglaciation in the AP is based on the dating of glacial landforms using CRE methods. In James Ross Island, one of the areas with most CRE dates available, deglaciation was intense until 6 ka (Hodgson et al., 2011;[START_REF] Glasser | Ice-stream initiation, duration and thinning on James Ross Island, northern Antarctic Peninsula[END_REF] and neoglacial advances occurred at ~4.8 ka and from 1.5 to 0.3 ka ( 10 Be ages) [START_REF] Davies | Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula[END_REF]. Close to James Ross Island, in Solari Bay, the Sjögren, Boydell and Drygalski glaciers advanced at 1.4 ka ( 10 Be ages) [START_REF] Balco | Exposure-age record of Holocene ice sheet and ice shelf change in the northeast Antarctic Peninsula[END_REF].

Recently, a work focusing on James Ross Island area reported 49 10 Be ages of Holocene glacial landforms [START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF]. These results suggest that the major glacial advance following the HTM occurred at ∼7-4 ka, with subsequent phases of glacier expansion between 3.9 and 3.6 ka, just after 3 ka, between ∼2.4 and ∼1 ka, and from ∼0.3 to ∼0.1 ka [START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF].

Using CRE dating, neoglacial advances were also detected in the western AP region, as in Alexander Island, Marguerite Bay, where a period of glacial expansion took place at 4.4 ± 0.7 and 1 ka ( 10 Be ages) [START_REF] Davies | Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula[END_REF]. Neoglacial advances have been reported in other areas in Antarctica, such as in the Darwin Mountains between 3 and 0.5 ka ( 10 Be ages) [START_REF] Storey | Cosmogenic nuclide exposure age constraints on the glacial history of the Lake Wellman area, Darwin Mountains, Antarctica[END_REF] (Fig. 1 and Table 1).

(vi) Neoglaciation in the South Shetland Islands. The SSI archipelago, located NW of the AP, lies at 120 km from the AP. The existence of neoglacial landforms in the SSI is known since the last third of the 20th century (Fig. 2 and Table 2). In the first geomorphological studies, at the end of the 1960s and early 1970s, researchers focused on the existence of moraines distributed a few hundred meters away from the present-day glacier fronts, which transgressed and overlapped recent raised beaches [START_REF] Araya | Estudio geomorfológico y geológico en las Islas Shetland del Sur Antártica[END_REF][START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF][START_REF] John | Evidence from the South Shetland Islands towards a glacial history of West Antarctica[END_REF][START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF].

This geomorphological pattern was first described in several deglaciated areas of the SSI, such as Byers and Hurd peninsulas (Livingston Island) and Fildes peninsula (King George Island). Since then, attention has been paid to inferring the age of deglaciation of these raised beaches and their relationship with moraines which transgressed them. Previous works considered that the raised beaches formed as a result of glacio-isostatic rebound due to the partial deglaciation of these islands. The existence of moraines distributed on some of these raised beaches suggest that the moraines are chronologically younger than the raised beaches. Radiocarbon dating of organic fragments interbedded in the raised beach provide a minimum age for the formation of the moraine resting on this beach. In Hurd Peninsula, [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF] inferred a phase of glacial expansion that advanced on a raised beach at 10-12 m a.s.l. and a subsequent glacier advance that left a moraine on a raised beach at 4-6 m a.s.l., which was known as the "False Bay event" [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF].

The application of radiocarbon dating to raised beaches at 4-6 m a.s.l. in Fildes Peninsula yielded an age of 0.4-0.7 cal ka BP. As this level of the raised beach (4-6 m a.s.l.) is frequently occupied by the youngest moraines existing in the SSI, geomorphologists deduced that these moraines were of LIA age [START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF][START_REF] John | Evidence from the South Shetland Islands towards a glacial history of West Antarctica[END_REF][START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF]. Subsequently, further radiocarbon dates differentiate between two levels of raised beaches in the SSI that were covered by the last neoglacial advances:

(i) the first one at 6 m a.s.l., (varying locally between 5 and 7.5 m a.s.l.) associated with a 2-3 km glacier readvance dated at the 13th to early 16th centuries A.D., and (ii) another one at 2-3 m a.s.l. associated with a 0.25-1 km glacier readvance at approximately the 15-17th centuries A.D, that in some areas overlapped the previous [START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF][START_REF] Sugden | Glacial history of the Antarctic Peninsula and South Georgia[END_REF][START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF]. Further radiocarbon dates of raised beaches also suggest, at least, two neoglacial advances between 3 and 1 cal ka BP [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF]. The application of lichenometric dating to the moraines distributed on the lowest raised beaches in the SSI confirmed that these landforms developed during LIA glacial advances [START_REF] Birkenmajer | Raised marine features and glacial history in the vicinity of H. Arctowski Station, King George Island (South Shetland Islands, West Antarctica)[END_REF][START_REF] Birkenmajer | Glacier retreat and raised marine beaches at Three Sisters Point, King George Island (South Shetland Islands, West Antarctica)[END_REF][START_REF] Birkenmajer | Quaternary geology at Potter Peninsula, King George Island (South Shetland Islands, West Antarctica)[END_REF] (Fig. 2 and Table 2).

To better understand the relationship between glacial advances and raised beaches transgressed by moraines, a more accurate geomorphological mapping was conducted to determine the altitude and extent of raised beaches in the Byers Peninsula [START_REF] Arche | Marine landforms and deposits[END_REF] and their correlation with those existing in other ice-free areas in this archipelago [START_REF] Fretwell | Holocene isostatic uplift of the South Shetland Islands, Antarctic Peninsula, modelled from raised beaches[END_REF]. The abundance of ice rafted debris of allochthonous lithology on raised beaches dated between 0.25 and 1.7 cal ka BP suggest that these beaches were related to cold periods of increased glacial extent and greater iceberg delivery [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF]. In addition, the dating of the highest raised beaches (located at about 16-20 m a.s.l.) indicates that the most massive deglaciation phase in this peninsula occurred between 9 and 6 cal ka BP, with glaciers close to their current position by 5.5 cal ka BP [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF][START_REF] Mäusbacher | Die jungquartäre Relief-und Klimageschichte im Bereich der Fildeshalbinsel Su¨d-Shetland-Inseln[END_REF][START_REF] Valle | Mid-Holocene macrofossil-bearing raised marine beaches at Potter Peninsula, King George Island, South Shetland Islands[END_REF][START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF][START_REF] Watcham | A new Holocene relative sea level curve for the South Shetland Islands, Antarctica[END_REF].

New records obtained during the early 21st century have improved our knowledge on the age of moraines in the SSI (Fig. 2 and Table 2). The oldest moraines in Livingston Island identified by [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF] were dated at >7.3 ka, predating the formation of the oldest raised beaches [START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF][START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF][START_REF] López-Martínez | Geomorphology of Hurd Peninsula, Livingston Island, South Shetland Islands[END_REF][START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF][START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF][START_REF] Fretwell | Holocene isostatic uplift of the South Shetland Islands, Antarctic Peninsula, modelled from raised beaches[END_REF]. [START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF] dated by radiocarbon the youngest moraines previously studied in Fildes and Hurd Peninsulas (Everett, 1971, John and[START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF][START_REF] John | Evidence from the South Shetland Islands towards a glacial history of West Antarctica[END_REF][START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF]. However, [START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF] considers the possibility that there could have been previous advances as old as 2.8 cal ka BP. Radiocarbon ages from a 4-6 m raised beach related to these moraines support glacial advance and transgression during the LIA. The application of Optically Stimulated Luminescence (OSL) dating methods to these younger beaches at 4-6 m in the Fildes Peninsula confirmed an age of the 16-18th centuries AD, which coincided with the LIA (Simms et al., 2011a[START_REF] Simms | Timing of the most recent Neoglacial advance and retreat in the South Shetland Islands, Antarctic Peninsula: insights from raised beaches and Holocene uplift rates[END_REF].

On the one hand, at the end of the 80s and beginning of the 90s, sediment cores collected from several lakes in Livingston and King George Islands reported radiocarbon minimum ages of 4-5 cal ka BP for deglaciation [START_REF] Mäusbacher | Evolution of postglacial sedimentation in Antarctic lakes (King George Island)[END_REF][START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF][START_REF] Björck | Palaeoclimatic studies in South Shetlands Islands, Antarctica, based on numerous stratigraphic variables in lake sediments[END_REF][START_REF] Björck | Holocene glacial chronology from lake sediments[END_REF]. The analysis of lake sediments from a number of lakes in the western part of the Byers Peninsula suggested the occurrence of a warm period occurring between 3.2 and 2.7 cal ka BP [START_REF] Björck | Palaeoclimatic studies in South Shetlands Islands, Antarctica, based on numerous stratigraphic variables in lake sediments[END_REF] and a remarkable cooling between 1.5 and 0.5 cal ka BP [START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF]. More recent studies suggest that the onset of the deglaciation of the Byers Peninsula occurred at 8.3 cal ka BP [START_REF] Toro | Chronostratigraphy of the sedimentary record of Limnopolar Lake, Byers Peninsula, Livingston Island, Antarctica[END_REF], with the deglaciation of the central plateau taking place between 8.3 and 5.9 cal ka BP and ice-free exposure of the easternmost fringe, close to the present-day glacier front, around 1.8 cal ka BP [START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF].

CRE dating methods were applied to polished bedrock surfaces in the Barton Peninsula (King George Island) along a transect from the highest peaks to the coast. These data showed that deglaciation of this small peninsula had begun earlier than inferred from lake sediments and raised beaches, between 17 and 14 ka, and had finished 1 ka ago [START_REF] Seong | Rate of late Quaternary ice-cap thinning on King George Island, South Shetland Islands, West Antarctica defined by cosmogenic 36Cl surface exposure dating[END_REF]. [START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF] CRE dated moraines from Hurd Peninsula and Marion Cove (King George Island) at 1.5-1.0 ka (Hall and Stone, personal communication).

Finally, the analysis of marine sediments in Maxwell Bay (King George Island)

determined that there was rapid glacial retreat from 10.1 to 8.2 cal ka BP and a period of gradual cooling and more extensive sea-ice cover in the bay from 5.9 cal ka BP onwards, with no evidence of LIA glacial advance [START_REF] Milliken | High-resolution Holocene climate record from Maxwell Bay, South Shetland Islands, AntarcticaHolocene climate record from Maxwell Bay[END_REF]. However, a more recent study of marine sediments in Maxwell Bay confirmed that the deglaciation began as soon as 14 cal ka BP -as was proposed by CRE dating in the nearby Barton Peninsula [START_REF] Seong | Rate of late Quaternary ice-cap thinning on King George Island, South Shetland Islands, West Antarctica defined by cosmogenic 36Cl surface exposure dating[END_REF] -and that deglaciation was completed by 5.9 cal ka BP, with a neoglacial advance into the bay ending at approximately 1.7 ka (Simms et al., 2011a). Recent coastal sediment analysis in Fildes Peninsula showed a cold period from 5.8 to 4.8 cal ka BP, a mid-Holocene climatic optimum between 4.4 and 2.7 cal ka BP, and the onset of Neoglaciation at 2.7 cal ka BP [START_REF] Chu | Depositional environment and climate changes during the Holocene in Grande Valley, Fildes Peninsula, King George Island, Antarctica[END_REF]. Sediment cores obtained from the continental shelf of the northern SSI pointed to the existence of a cold period around 0.33 cal ka BP, which must have corresponded to the LIA [START_REF] Yoo | Sedimentological, geochemical and palaeontological evidence for a neoglacial cold event during the late Holocene in the continental shelf of the northern South Shetland Islands, West Antarctica[END_REF].

To sum up, despite varied results, a common pattern can be deduced in studies of neoglacial phases in the SSI in the context of AP region. The glaciers were similar to or smaller than present-day in the AP, as in the SSI, around 6 ka.

Before the warmer period detected in the AP between 4.5 and 2.8 cal ka BP (Bentley et al., 2009), a cold period with the first neoglacial advances occurred around 5 ka in many places of the AP and the rest of the continent [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF][START_REF] Mosley-Thompson | Holocene climate changes recorded in an East Antarctica ice core. Climatic variations and forcing mechanisms of the last 2,000[END_REF][START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF][START_REF] Heroy | Holocene climate change in the Bransfield Basin, Antarctic Peninsula: evidence from sediment and diatom analysis[END_REF]Bentley et al., 2009;[START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF][START_REF] Carrivick | Late Holocene changes in character and behaviour of land-terminating glaciers on James Ross Island, Antarctica[END_REF][START_REF] Cofaigh | Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF][START_REF] Davies | Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula[END_REF][START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF]. So far, there is no evidence of this neoglacial advance in the SSI, except perhaps for the references made by [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF] in the Hurd Peninsula about moraines in relation to the raised beaches at 10-12 m a.s.l.

Another period of widespread neoglacial advance took place in the AP between 2.8 and 1.4 ka, with cooling intensifying between 1.8 and 1.4 cal ka BP. [START_REF] Mosley-Thompson | Holocene climate changes recorded in an East Antarctica ice core. Climatic variations and forcing mechanisms of the last 2,000[END_REF][START_REF] Björck | Late Holocene palaeoclimatic records from lake sediments on James Ross Island, Antarctica[END_REF][START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Heroy | Holocene climate change in the Bransfield Basin, Antarctic Peninsula: evidence from sediment and diatom analysis[END_REF]Bentley et al., 2009;[START_REF] Yoon | Late Holocene cyclic glaciomarine sedimentation in a subpolar fjord of the South Shetland Islands, Antarctica, and its paleoceanographic significance: sedimentological, geochemical, and paleontological evidence[END_REF][START_REF] Domack | Chronology of the Palmer Deep site, Antarctic Peninsula: A Holocene palaeoenvironmental reference for the circum-Antarctic[END_REF][START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF][START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF][START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF][START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Abram | Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century[END_REF][START_REF] Hodgson | Late Quaternary environmental changes in Marguerite Bay, Antarctic Peninsula, inferred from lake sediments and raised beaches[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF][START_REF] Davies | Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula[END_REF]Davies et al., , Čejka et al., 2019;;[START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF]. To date, this glacial advance is also poorly represented in the SSI, with the only reference by [START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF][START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF]. However, there is some evidence of a cold period around 1.8 ka in the SSI from other paleoclimatic proxies, such as ice rafted debris on raised beaches [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF], lake sediments [START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF][START_REF] Björck | Palaeoclimatic studies in South Shetlands Islands, Antarctica, based on numerous stratigraphic variables in lake sediments[END_REF][START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF], and marine records [START_REF] Chu | Depositional environment and climate changes during the Holocene in Grande Valley, Fildes Peninsula, King George Island, Antarctica[END_REF].

The information available on glacial advances during the LIA is varied across the AP, as in the SSI. Similarly, there is clear evidence of advances in some areas [START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF], but it is absent in archives such as lake and marine sediments [START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF][START_REF] Hodgson | Late Quaternary environmental changes in Marguerite Bay, Antarctic Peninsula, inferred from lake sediments and raised beaches[END_REF] as well as in ice core records [START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Brightley | A Paleoclimate Reconstruction of the Little Ice Age to Modern Era Climate Conditions in the Eastern Ross Sea, Antarctica as Captured in the RICE Ice Core[END_REF]. In any case, it is important to note that in many areas a cooling period was observed from 1.5 ka to the first cooling events associated with the LIA [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF][START_REF] Domack | Chronology of the Palmer Deep site, Antarctic Peninsula: A Holocene palaeoenvironmental reference for the circum-Antarctic[END_REF][START_REF] Hall | Holocene history of the Wilson Piedmont Glacier along the southern Scott Coast[END_REF][START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF][START_REF] Storey | Cosmogenic nuclide exposure age constraints on the glacial history of the Lake Wellman area, Darwin Mountains, Antarctica[END_REF][START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Balco | Exposure-age record of Holocene ice sheet and ice shelf change in the northeast Antarctic Peninsula[END_REF][START_REF] Davies | Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula[END_REF][START_REF] Davies | Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula[END_REF]. On the other hand, most of the studies carried out on the youngest moraines of the SSI, transgressing the 4-6 m raised beach, confirmed that they were formed during the LIA, between the 16th and 18th centuries AD, with minor age differences depending on dating methods.

Geographical setting of the case study: the Byers Peninsula

With the aim of resolving the discrepancies observed between the SSI and the rest of the AP on the timing of development of neoglacial landforms, this work explores the age of formation of several landforms in an area that is already known to have been deglaciated

during the Mid-Late Holocene [START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF], the Byers Peninsula, the largest icefree area in the SSI (Fig. 2 and Table 3). The Byers Peninsula (62º34'35''-62º40'35''S, 60º54'14''-61º13'07''W) is located on the western end of Livingston Island, the second largest island in the SSI, with an area of approximately 60 km 2 , and a maximum altitude of 265 m a.s.l.. The peninsula is part of a Jurassic-Quaternary magmatic forearc generated by Mesozoic and Cenozoic subduction processes along the South Shetland Trench [START_REF] Smellie | Geology of a Mesozoic intra-arc sequence on Byers Peninsula, Livingston Island, South Shetland Islands[END_REF][START_REF] Alfaro | Recent tectonic and morphostructural evolution of Byers Peninsula (Antarctica): insight into the development of the South Shetland Islands and Bransfield Basin[END_REF]. This peninsula is composed of Upper Jurassic-Lower Cretaceous sedimentary deposits (mainly sandstones, mudstones and conglomerates) and volcanic and volcanoclastic rocks, with abundant intrusive igneous rocks of basalt-basaltic andesite composition [START_REF] Smellie | Geology of a Mesozoic intra-arc sequence on Byers Peninsula, Livingston Island, South Shetland Islands[END_REF][START_REF] Hathway | The Upper Jurassic-Lower cretaceous Byers Group, South Shetland Islands, Antarctica: revised stratigraphy and regional correlations[END_REF][START_REF] Parica | Geología de la formación Cerro Negro (Cretácico) en la isla Livingston: aportes a su geocronología y contenido paleontológico[END_REF][START_REF] Alfaro | Recent tectonic and morphostructural evolution of Byers Peninsula (Antarctica): insight into the development of the South Shetland Islands and Bransfield Basin[END_REF]. The geomorphology of the Byers Peninsula [START_REF] Araya | Estudio geomorfológico y geológico en las Islas Shetland del Sur Antártica[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF]López-Martínez et al., 1996) [START_REF] Birkenmajer | Retreat of Ecology Glacier, Admiralty Bay, King George Island (South Shetland Islands, West Antarctica), 1956-2001[END_REF]) that seems to have decelerated in the last decade [START_REF] Navarro | Decelerated mass loss of Hurd and Johnsons Glaciers, Livingston Island, Antarctic Peninsula[END_REF]Oliva et al., 2017).

The mean annual temperature is around -2.8 °C at 80 m and annual precipitation (rain and snowfall) reaches ca. 650 mm at this altitude [START_REF] Bañón | Regional weather survey on Byers Peninsula, Livingston Island, South Shetland Islands, Antarctica[END_REF][START_REF] De Pablo | Thermal characterization of the active layer at the Limnopolar Lake CALM-S site on Byers Peninsula (Livingston Island), Antarctica[END_REF]. Discontinuous permafrost patches have been detected in raised beaches [START_REF] Correia | Evaluation of frozen ground conditions along a coastal topographic gradient at Byers Peninsula (Livingston Island, Antarctica) by geophysical and geoecological methods[END_REF] whereas permafrost is continuous at the central plateau [START_REF] De Pablo | Thermal characterization of the active layer at the Limnopolar Lake CALM-S site on Byers Peninsula (Livingston Island), Antarctica[END_REF].

Abundant periglacial landforms distributed across the peninsula show evidence of active periglacial dynamics in the area, strongly conditioned by local topography and snow distribution [START_REF] Serrano | Periglacial and nival landforms and deposits[END_REF][START_REF] López-Martínez | Periglacial processes and landforms in the South Shetland Islands (northern Antarctic Peninsula region)[END_REF][START_REF] Hrbáček | Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region[END_REF]Ruiz-Fernández et al., 2016;[START_REF] Oliva | Active layer dynamics in three topographically distinct lake catchments in Byers Peninsula (Livingston Island, Antarctica)[END_REF]. Most of the area is covered by bryophytes and lichens, including the two native Antarctic phanerogams on the raised beaches [START_REF] Lindsay | Vegetation of the South Shetland Islands[END_REF][START_REF] Vera | Distribution and reproductive capacity of Deschampsia antarctica and Colobanthus quitensis on Byers Peninsula, Livingston Island, South Shetland Islands, Antarctica[END_REF], which makes the Byers Peninsula a unique environment in terms of terrestrial biodiversity within Antarctica [START_REF] Benayas | A review of scientific research trends within ASPA no. 126 Byers Peninsula, South Shetland Islands, Antarctica[END_REF][START_REF] Almela | Carbon pathways through the food web of a microbial mat from Byers Peninsula, Antarctica[END_REF]). To protect this hotspot of biodiversity, the Byers Peninsula was designated an Antarctic Specially Protected Area (ASPA N° 126).

The Byers Peninsula was covered by an ice sheet distributed across the SSI during the last glacial cycle [START_REF] Araya | Estudio geomorfológico y geológico en las Islas Shetland del Sur Antártica[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF]López Martínez et al., 1996). This ice sheet was connected with the AP ice sheet during the maximum ice extent, though it became isolated as ice started thinning during the deglaciation [START_REF] Cofaigh | Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum[END_REF]. Previous studies on lake sediments have determined that the deglaciation of the Byers Peninsula occurred from W to E, with a timing of 7.5 to 1.8 cal ka BP [START_REF] Toro | Chronostratigraphy of the sedimentary record of Limnopolar Lake, Byers Peninsula, Livingston Island, Antarctica[END_REF][START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF]Ruiz-Fernández and Oliva, 2016). Domo Lake, located only at 350 m from the present glacier front, was deglaciated around 1.8 ka [START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF].

Several geomorphological landforms and deposits of glacial origin are distributed between the contemporary glacial front and the sea. This is the case of the large longitudinal ice-cored moraines located in front of the Rotch Dome Glacier (Martinez de Pisón et al., 1996;Ruiz-Fernández et al., 2016). [START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF] observed how these moraines override all marine levels incorporating littoral deposits; they suggested that the most recent moraines were directly related to the 4-6 m beach and were contemporary in age, representing thus a recent glacial readvance. [START_REF] Hansom | Radiocarbon dating of a raised beach at 10 m in the South Shetland Islands[END_REF] radiocarbon dated a 10 m a.s.l. raised beach at 1.8 cal ka BP, whereas [START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF] reported that the 6 m a.s.l. raised beach formed during the 15-17th centuries AD. [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF] suggested that this beach and the 10 m a.s.l. unit formed during cold periods over the last 1.7 cal ka BP, as they are rich in ice rafted debris. [START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF] contributed numerous dates for all the sequences of raised beaches in the main complexes of the Byers Peninsula, concluding that the highest levels formed at 7.4 cal ka BP and confirming that the 6 m a.s.l. raised beach developed during the 15-17th centuries AD. The frontal icecored moraines in front of the Rotch Dome Glacier have been very stable over the last decades, as can be seen in photos and descriptions in old publications [START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF]López Martínez et al., 1996;[START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF]. The glacier has retreated from these moraines only in the vicinity of the northern coast and in the southern fringe, around Clark Nunatak (Martinez de Pisón et al., 1996). In the nearby peninsula of Elephant Point, only 3 km SE of Clark Nunatak, a similar retreat occurred from 1956 to 2000 [START_REF] Oliva | Conceptualization[END_REF]Ruiz-Fernández, 2015, 2017) (Fig. 2 and Table 3).

Methodology

Geomorphological research and sampling strategy

In the eastern fringe of the Byers Peninsula, next to Rotch Dome Glacier, an ice-cored moraine has been described to be in contact with the glacier front from 1966 to 1996 [START_REF] Araya | Estudio geomorfológico y geológico en las Islas Shetland del Sur Antártica[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF]Martinez de Pisón et al., 1996) (Fig. 2).

Over these thirty years, the limits, extent, and shape of the ice-cored moraine crests were identical to those described in earlier observations (Martinez de Pisón et al., 1996),

showing evidence of the prevailing geomorphic stability at annual to decadal timescales (López Martínez et al., 1996;[START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF]. The ice-cored moraine system develops from a single polygenic ridge in the southern edge to a sequence of twelve ridges in its northern fringe next to Robbery beaches (Ruiz-Fernández et al., 2016). These ice-cored moraines are similar to those described in other areas of the AP region [START_REF] Hambrey | Structure and sedimentology of George VI Ice Shelf, Antarctic Peninsula: implications for ice-sheet dynamics and landform development[END_REF]. As for Hurd and Fildes peninsulas, Martínez de Pisón et al., (1996) proposed also a synchronicity between the timing of formation of raised beaches and moraines in the Byers Peninsula.

The objective of the geomorphological research was to explore the existence of moraines disconnected from the glacier front of the Roch Dome Glacier, which would suggest the occurrence of neoglacial advances. Roch Dome Glacier moraines include sediments transported by the glacier from the interior of the island, and, therefore, are mostly composed of basalts. We sampled some of these moraine boulders to apply CRE dating using in situ 36 Cl. These moraines transgressed raised beaches whose age is already well constrained [START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF]2010) and provide a minimum age for the development of the moraines that lay on them. In addition, researchers already identified the existence of icerafted granite boulders on these raised beaches [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF]. These boulders were sampled to be dated using the in situ-produced 10 Be dating method to study their possible chronological relationship with the sampled moraine. Finally, we collected samples from glacially polished bedrock surfaces close to the present glacier front for 36 Cl dating in order to date the glacier retreated from this position.

CRE sampling and analytical procedures

During the fieldwork campaign, a total of 12 samples were taken from glacially polished outcrops and >1-m-diameter erratic/moraine boulders by means of hammer and chisel.

We focused on flat gentle surfaces on the top of the boulders/outcrops and avoided steep surfaces and sharp crests in order to ensure the optimal cosmic-ray flux reception. We selected the most stable boulders, which were rooted in the moraines, with no signs of spalling or fracturing and that could not have been deposited through gravitational processes from rock walls. The thickness of the samples ranged from 1.8 to 4.5 cm (Table 4). Following the sample collection, they were crushed and sieved to the 0.25-1 mm fraction at the "Physical Geography Laboratory" of the Complutense University of Madrid. Then the samples were physically and chemically processed at the "Laboratoire National des Nucléides Cosmogéniques" (LN2C) of the "Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement" (CEREGE, Aix-en-Provence, France). As the sampled surfaces were constituted both by basaltic and granitic rocks (Table 4), samples were processed for measurement of the in situ cosmogenic nuclides 36 Cl (10 samples) and 10 Be (2 samples) by accelerator mass spectrometry (AMS), respectively.

In the case of the 36 Cl, the sample preparation procedures were similar to those described in [START_REF] Schimmelpfennig | Calibration of cosmogenic 36Cl production rates from Ca and K spallation in lava flows from Mt. Etna (38°N, Italy) and Payun Matru (36°S, Argentina)[END_REF]. Magnetic separation was performed on one sample (BYC-10) to isolate the abundant feldspar minerals for 36 Cl extraction by discarding the magnetic minerals with a magnetic separator "Frantz LB-1". 36 Cl extraction from whole rock was conducted for the other 9 samples, which had insufficient amounts of feldspar minerals. In both cases, aliquots of untreated bulk sample were taken to determine the sample composition (major and trace elements; Table 5). Samples with initial weights of 120 g were rinsed and shaken with ultrapure water for 3 hours to remove dust and fines.

After that, between 40 and 50% of the initial weight was dissolved with a mixture of diluted nitric acid (10% HNO 3 ) and concentrated hydrofluoric acid (48% HF) in order to remove atmospheric 36 Cl and potentially Cl-rich groundmass. After this partial dissolution, the remaining etched sample mass was rinsed and dried, and 2-g aliquots were taken to determine the major element concentrations ( After the total dissolution, the samples were centrifuged to discard the undissolved residues and gel (fluoride complexes, CaF 2 ). Then, the chlorine in the liquid solution was precipitated to silver chloride (AgCl) by adding 2 ml of a silver nitrate (AgNO 3 ) solution at 10%. To achieve this, samples were stored for 2 days in a dark place to allow the AgCl to settle down on the bottom of the bottles. This enabled the extraction of the supernatant solution (excess HF and HNO 3 ) by a peristaltic pump avoiding the disturbance of the AgCl precipitate. In the next step, aiming to reduce the isobaric interferences of 36 S throughout the 36 Cl measurements in the Accelerator Mass Spectrometer (AMS) sulphur was removed in the form of barium sulphate (BaSO 4 ) obtained after the re-dissolution of this first AgCl precipitate and the addition of 1 mL of a saturated solution of barium nitrate (Ba(NO 3 ) 2 ). BaSO 4 was discarded by centrifuging and filtering the supernatant with a syringe and an acrodisc filter. Then, AgCl was precipitated again with 3-4 mL of diluted HNO 3 (1:1 vol.). The precipitate was collected after centrifuging, and was rinsed and finally dried in the oven at 80 ºC for 2 days. Once the AgCl precipitate was completely dried, it was loaded in cathodes. Subsequently, targets were stored in the oven in order to protect them from atmospheric humidity until they were measured by AMS.

For the 10 Be extraction, the processing started with the quartz isolation from the bulk rock.

Magnetic minerals were discarded by using the magnetic separator "Frantz LB-1". After that, the non-magnetic fraction was chemically attacked at successive rounds with a mixture of concentrated hydrochloric (1/3 HCl) and hexafluorosilicic (2/3 H 2 SiF 6 ) acids aiming to dissolve non-quartz minerals. Then, the remaining minerals were decontaminated from meteoric 10 Be by means of three successive partial dissolutions with concentrated HF, which also dissolved the remaining impurities from the previous step.

The samples yielded 60-80 g of purified quartz (Table 7). Before the total dissolution, 150 μL of a 9 Be carrier solution (concentration: 3025 ± 9 μg g -1 ; [START_REF] Merchel | Towards more precise 10 Be and 36 Cl data from measurements at the 10-14 level: Influence of sample preparation[END_REF] manufactured in-house from a phenakite crystal were added to the samples. Quartz was totally dissolved in 48 % HF (3.6 mL per g of quartz + 30 mL in excess). The resulting solutions were evaporated until dryness and samples were recovered with hydrochloric acid. Subsequently samples were precipitated with ammonia before successive separations through an anion exchange column (Dowex 1X8) to remove iron and a cation exchange column (Dowex 50WX8) to discard boron (isobar) and recover Be [START_REF] Merchel | An update on radiochemical separation techniques for the determination of long-lived radionuclides via accelerator mass spectrometry[END_REF]. Finally, the eluted Be was precipitated to Be(OH) 2 with ammonia and oxidized to BeO at 700 °C. The targets were prepared by mixing Niobium powder with the BeO oxide for AMS measurements.

The final AgCl and BeO targets were analysed at the AMS facility ASTER "Accélérateur pour les Sciences de la Terre, Environnement et Risques" at CEREGE to measure the specific isotope ratios for 36 Cl ( 35 Cl/ 37 Cl and 36 Cl/ 35 Cl) and 10 Be ( 10 Be/ 9 Be) dating. The 36 Cl measurements were normalized to the in-house standard SM-CL-12 with an assigned 36 Cl/ 35 Cl ratio value of (1.428 ± 0.021) x 10 -12 [START_REF] Merchel | Ultra-trace analysis of 36Cl by accelerator mass spectrometry: an interlaboratory study[END_REF] and assuming a natural 35 Cl/ 37 Cl ratio of 3.127. The 10 Be measurements were calibrated against the inhouse standard STD-11, using an assigned 10 Be/ 9 Be ratio of (1.191 ± 0.013) x 10 -11 [START_REF] Braucher | Preparation of ASTER in-house 10 Be/ 9 Be standard solutions[END_REF]. Analytical 1σ uncertainties include uncertainties in AMS counting statistics, the standard 10 Be/ 9 Be ratio, an external AMS error of 0.5% [START_REF] Arnold | The French accelerator mass spectrometry facility ASTER: Improved performance and developments[END_REF] and a chemical blank measurement. A 10 Be half-life of (1.387 ± 0.0012) x 10 6 years was used [START_REF] Chmeleff | Determination of the 10 Be half-life by multicollector ICP-MS and liquid scintillation counting Nuclear Instruments and Methods in Physics Research[END_REF][START_REF] Korschinek | A new value for the half-life of 10 Be by Heavy-Ion Elastic Recoil Detection and liquid scintillation counting[END_REF].

We calculated 36 Cl ages using two different procedures. On the one hand, the Excel™ spreadsheet for in situ 36 Cl exposure age calculations designed by [START_REF] Schimmelpfennig | Sources of in-situ 36Cl in basaltic rocks. Implications for calibration of production rates[END_REF], as it allows using different 36 Cl production rates from spallation. In this case, the elevation-latitude scaling factors were based on the time invariant "St" scheme [START_REF] Stone | Air pressure and cosmogenic isotope production[END_REF]. The production rate of epithermal neutrons for fast neutrons in the atmosphere at the land/atmosphere interface was 696±185 neutrons (g air) -1 yr -1 [START_REF] Marrero | CRONUS -Earth cosmogenic 36Cl calibration[END_REF].

The high-energy neutron attenuation length value applied was 160 g cm -2 . We used the following 36 Cl production rates -references to sea-level and high latitude (SLHL)-from spallation of different elements: 42.2±4.8 atoms 36 Cl (g Ca) -1 yr -1 for Ca spallation [START_REF] Schimmelpfennig | Calibration of cosmogenic 36Cl production rates from Ca and K spallation in lava flows from Mt. Etna (38°N, Italy) and Payun Matru (36°S, Argentina)[END_REF], 148.1±7.8 atoms 36 Cl (g K) -1 yr -1 for K spallation [START_REF] Schimmelpfennig | 36 Cl production rate from K-spallation in the European Alps (Chironico landslide, Switzerland)[END_REF], 13±3 atoms 36 Cl (g Ti) -1 yr -1 for Ti spallation [START_REF] Fink | Cross-sections for 36Cl from Ti at Ep=35-150 MeV: Applications to in-situ exposure dating[END_REF], 1.9±0.2 atoms 36 Cl (g Fe) -1 yr -1 for Fe spallation (Stone et al., 2005). On the other hand, we calculated the 36 Cl exposure ages using the trial version of the online calculator CREp for 36 Cl [START_REF] Schimmelpfennig | The CREp Chlorine-36 exposure age and depth profile calculator[END_REF], where the "LSD" (Lifton-Sato-Dunai) elevation latitude scaling scheme was implemented, together with the LSD geomagnetic database framework [START_REF] Lifton | Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes[END_REF] and the same production rates from the spallation of the abovementioned elements. As Ca spallation is the most dominant 36 Cl production reaction and the [START_REF] Schimmelpfennig | Calibration of cosmogenic 36Cl production rates from Ca and K spallation in lava flows from Mt. Etna (38°N, Italy) and Payun Matru (36°S, Argentina)[END_REF] production rate was calibrated at the Etna volcano (i.e. an area with a different atmospheric setting from the Antarctica sampling sites), we corrected the atmospheric pressure of the sampling sites. South Shetland Islands are affected by permanent subpolar low-pressure systems, which affect the cosmic-ray particle flux so that it influences (i.e. increases) the local cosmogenic nuclide production rate. Consequently, this atmospheric pressure anomaly has to be taken into account when scaling the SLHL production rates. In fact, [START_REF] Dunai | Cosmogenic Nuclides[END_REF] advises including any long-term atmospheric pressure anomaly at least for Holocene exposure periods. Thus, the atmospheric pressure value was corrected for the elevation of each sampling site by implementing the ERA40 [START_REF] Uppala | The ERA-40 re-analysis[END_REF] atmosphere model using the MATLAB function "ERA40.mat" [START_REF] Lifton | Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes[END_REF]. The specific Antarctica atmosphere model [START_REF] Stone | Air pressure and cosmogenic isotope production[END_REF] was not used as the atmosphere in continental Antarctic is affected by the air flow over the ice-sheet, which impacts the elevation/air pressure relationship in the opposite way (thermal high pressure at surface level). The 36 Cl ages that will be presented and discussed throughout this work are those obtained from the "LSD" scaling scheme so that they are comparable to the 10 Be ages.

Finally, 10 Be exposure ages were calculated by using the online calculator "CREp" [START_REF] Martin | The CREp program and the ICE-D production rate calibration database: A fully parameterizable and updated online tool to compute cosmic-ray exposure ages[END_REF]; available online at: http://crep.crpg.cnrs-nancy.fr/#/). In this calculator, we applied again the "LSD" elevation latitude scaling scheme [START_REF] Lifton | Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes[END_REF], the ERA40 atmospheric model [START_REF] Uppala | The ERA-40 re-analysis[END_REF] and the geomagnetic database based on the LSD framework [START_REF] Lifton | Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes[END_REF]. These parameters yield a SLHL 10 Be production rate from Be spallation of 3.98±0.22 atoms g -1 yr -1 .

We include the results, with total error and analytical errors in Table 7 and Fig. 3. In the text and in the figures we show the results with the total error. We do not have any quantitative information on the snow cover during the surface exposure duration.

Therefore, samples were taken from surfaces that are exposed to strong winds, in order to limit the potential effects of prolonged snow cover on the cosmogenic nuclide production. We also avoided surfaces that showed signs of significant erosion or spalling.

In addition, denudation rates in Antarctica are reported to be extremely low (0-1 m/Ma; e.g. [START_REF] Schäfer | Cosmogenic noble gas studies in the oldest landscape on earth: surface exposure ages of the Dry Valleys, Antarctica[END_REF][START_REF] Balco | Features of the glacial history of the Transantarctic Mountains inferred from cosmogenic 26 Al, 10 Be and 21 Ne concentrations in bedrock surfaces[END_REF], thus having no significant effect on the Holocene exposure ages. Hence, no corrections for potential effects of snow cover or denudation were applied to the ages, in consistency with other studies from this region (e.g. Ciner et al., 2019).

Results of the timing of neoglacial advance in the Byers Peninsula

Geomorphological setting of neoglacial landforms

The ice-cored moraine system in the present front of the Roch Dome Glacier is formed by sharp-crested ridges standing 50 to 70 m above the adjacent bedrock surface, with blocks >1 m in diameter (Fig. 4, 5 and 6). The extensive debris cover has a very high ice proportion, exceeding 60% of the total volume, according to field observations. The sediments are distributed in the direction of the glacier's foliation and its lithology reflects that of the basalt bedrock, which indicates that the moraine results from basal and englacial debris. From the moraine crests, a steep ramp of ice (40º slope) descends to the southern side of the peninsula. The unconsolidated sediments of the moraines are currently being intensely reworked by mass wasting processes, and are thus not appropriate for surface exposure dating methods (lichenometry or CRE).

This ice-cored moraine ridge overrides all raised beaches from the central plateau to the 6 m a.s.l. raised beach in the N and S coastal fringes (Fig. 4). Our research focuses on the southern sector of the moraine system, where it overlaps the raised beaches until the Clark Nunatak. Just SW of this nunatak, a small peninsula -called Rish Point -formed by a series of volcanic plugs stands only at 60 m from the coast line (Fig. 4, 5 and 6).

Next to the highest volcanic plug of the area (Ritli Hill, 45 m) (Fig. 4, 5, 6 and 7), we observed a glacial polished surface at an elevation of 28 m, and a distance of 600 m southwards of the present moraine ridge. Here, we collected the bedrock sample BYC-1.

On another volcanic plug, only 350 m from the moraine ridge and at elevation of 47 m, another polished surface was observed with an erratic on it. Samples were taken from bedrock surface BYC-2 and from the erratic boulder BYC-3.

On the western side of the Clark Nunatak, the ice ramp descending from the external part of the ice-core moraine ridge does not connect with the bedrock surface but to thick layers of till, which rest on the 10-12 m a.s.l. raised beach. At the connection between the till deposits and the raised beach, there is a group of large, stable erratic glacial boulders, aligned parallel to the limit of the glacier. This line of erratic boulders is located about 200 m to the S of the present glacier front and lies on the 10-12 m a.s.l. beach. These boulders are basalts and we assume that were deposited by Dome Rotch glacier during a small advance, when it trespassed the 10-12 m a.s.l. beach. The five largest and most stable basaltic boulders were selected from this line to take samples for 36 Cl dating (BYC-9, 10, 11, 13 and 14) (Fig. [START_REF] José | Conceptualization. Formal analysis[END_REF][START_REF] Schimmelpfennig | Exhaustive correction of the manuscript[END_REF][START_REF] González-Díaz | Formal analysis[END_REF]. In addition to the erratic basaltic boulders that rest on the 10-12 m a.s.l raised beach, there are some granite boulders that were embedded in the sediments of this raised beach protruding around a meter above the beach sand level. We assume that these granitic boulders were transported by icebergs from the AP during the beach formation, as there are no granitic rocks in Byers bedrock [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF].

We sampled two of the ice rafted granitic boulders (BYB-10 and BYC-12) (Fig. 4, 5, 6, 8 and 9). We assume that the ice-rafted boulders have been stable since they were deposited on the beach, and therefore CRE ages of these boulders must coincide with the age of formation of the beach where they are distributed.

On the other hand, there is a moraine ridge surrounding the W side of Clark Nunatak and with the eastern extreme of Rish Point, which trespassed the 4-6 m a.s.l. raised beach. This is one of the few sites in the Byers Peninsula where the current front of the glacier is separated from the ice-core moraine crest (distance of ca. 500 m). This moraine is formed by several crests and arcs that overlap one another. The youngest arcs constitute ice-cored moraine ridges and are very unstable and subject to mass movements and intense remobilization. The outer most crests are stable. Two boulders from this stable older sector of the moraine were selected for CRE samples (BYC-4 and 5), located at elevation of 35 m (Fig. 4, 5, 6, and 10).

CRE results

CRE results show a complex spatio-temporal pattern with regards to the glacial evolution during the Mid-Late Holocene in the Byers Peninsula.

The oldest ages correspond to the deglaciation of the Rish Point. Samples BYC-1 and 2 on the two polished surfaces located on the summit of volcanic plugs reported the same 36 Cl age of 10.4 ± 1.2 and 10.3 ± 1.3 ka. The erratic boulder BYC-3 deposited on the same polished surface as BYC-2 yielded a slightly younger 36 Cl age of 9.1 ± 1.1 ka. The arithmetic mean of these three samples is 9.9 ± 1.2 ka (n=3) (Fig. 3, 4, 5, 6 and Table 7).

The samples taken from the erratic boulders lying on the 10-12 m a.s.l. raised beach (BYC-9, 10, 11, 13 and 14) yielded the following 36 Cl ages: 3.0 ± 0.7, 4.2 ± 0.6, 3.6 ± 0.6, 4.7 ± 0.6 and 3.6 ± 0.7 ka, respectively. The arithmetic mean is 3.8 ± 0.6 ka (n=5). The ages of the granitic boulders embedded in the 10-12 m a.s.l. raised beach (BYB-10) and on the littoral platform (BYC-12) give 10 Be ages of 3.5 ± 0.4 ka and 5.5 ± 0.4 ka, respectively, with an arithmetic mean of 4.4 ± 0.4 ka (n=2). In fact all this ages are indistinguishable from each other with an average of 4.1± 0.5 ka (n=7) (Fig. 3, 4, 5, 6 and Table 7).

The two boulders distributed on the moraine from the eastern flank of the Clark Nunatak where the front of the glacier has significantly retreated over the last decades (BYC-4 and 5) showed similar Cl 36 ages of 1.1 ± 0.3 and 0.8 ± 0.2 ka, respectively. The mean is 1.0 ± 0.2 ka (n=2) (Fig. 3, 4, 5, 6 and Table 7).

Discussion

Analysis of the results in the context of the SSI and the AP

The here presented first CRE dates from the Byers Peninsula indicate the existence of three different periods concerning glacier evolution in the area. The first group of landforms correspond to the polished surfaces and the erratic boulder located in Rish

Point. These samples are indicative of the northwards retreat of Rotch Dome Glacier, which occurred at around 11-9 ka (9.9 ± 1.2 ka; n=3). This ice-free corner was deglaciated prior to the oldest raised beaches distributed at 15-16 m a.s.l. that were dated at 7.4 cal ka BP in the Byers Peninsula [START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF]2010). The age of these landforms fits also with the chronological framework of deglaciation inferred from lake records in this peninsula, suggesting that the initial deglaciation of the central plateau took place at 8.3 cal ka BP [START_REF] Toro | Chronostratigraphy of the sedimentary record of Limnopolar Lake, Byers Peninsula, Livingston Island, Antarctica[END_REF][START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF]. The Early Holocene deglaciation of coastal environments also occurred between 9 and 6 ka in the rest of the SSI [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF][START_REF] Mäusbacher | Die jungquartäre Relief-und Klimageschichte im Bereich der Fildeshalbinsel Su¨d-Shetland-Inseln[END_REF][START_REF] Valle | Mid-Holocene macrofossil-bearing raised marine beaches at Potter Peninsula, King George Island, South Shetland Islands[END_REF][START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF][START_REF] Watcham | A new Holocene relative sea level curve for the South Shetland Islands, Antarctica[END_REF], or even before 9 ka [START_REF] Milliken | High-resolution Holocene climate record from Maxwell Bay, South Shetland Islands, AntarcticaHolocene climate record from Maxwell Bay[END_REF][START_REF] Seong | Rate of late Quaternary ice-cap thinning on King George Island, South Shetland Islands, West Antarctica defined by cosmogenic 36Cl surface exposure dating[END_REF]Simms et al., 2011). This timing also coincides with data from other records from the AP, such as marine sediments, which show a clear warming trend beginning 12 ka ago [START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF], as well as from CRE dating of glacial landforms in this peninsula [START_REF] White | Cosmogenic nuclide evidence for enhanced sensitivity of an East Antarctic ice stream to change during the last deglaciation[END_REF][START_REF] Glasser | Ice-stream initiation, duration and thinning on James Ross Island, northern Antarctic Peninsula[END_REF][START_REF] Anderson | Reconciling marine and terrestrial evidence for post LGM ice sheet retreat in southern McMurdo Sound, Antarctica[END_REF] (Fig. 11).

A second group of landforms includes glacial basaltic boulders distributed on the beach and littoral platform at 10-12 m a.s.l (BYC 9,10,11,13 and 14) and the two ice rafted granitic boulders embedded in the sediments of this raised beach (BYB 10) or located on the same littoral platform (BYC 12). The results obtained show very similar ages for all types of boulders, both basalts and granites, with an average of 4.1± 0.5 ka (n=7).

Therefore, the ages of the stabilization of these boulders transported by the Rotch Dome Glacier should correspond to the age of this beach level, where ice rafted granitic boulders are embedded. Radiocarbon dating from whale bones of similar altitude raised beach in the South Beaches, suggested younger ages, between 2.6 and 2 cal ka BP [START_REF] Hansom | Radiocarbon dating of a raised beach at 10 m in the South Shetland Islands[END_REF][START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF][START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF]. These data coincide with OSL dates of this level of raised beaches from other islands in this archipelago, between 2.3 and 2.1 ka (Simms et al., 2011a and2012). Our results from the ice-drafted granitic boulders indicated older ages for this raised beach, 4.4 ± 0.4 ka (n=2), which are synchronous with the glacial boulders that are distributed on it. There is a lack of correspondence between the older ages of the erratic and ice-rafted boulders and the former much younger radiocarbon dates attributed to this raised beach. To understand this apparent contradiction, it is important to highlight that there is no direct dating of the raised beach in the area. Landforms at similar altitudes within the same region do not necessarily have identical chronologies, as glacio-isostatic uplift rates enhanced also by neotectonic activity vary throughout the archipelago [START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Fretwell | Holocene isostatic uplift of the South Shetland Islands, Antarctic Peninsula, modelled from raised beaches[END_REF][START_REF] Simms | Late Holocene relative sea levels near Palmer Station, northern Antarctic Peninsula, strongly controlled by late Holocene ice-mass changes[END_REF]. In fact, it seems reasonable that the raised beach at +10-12 m a.s.l where the erratic boulders are distributed may constitute an intermediate level between the raised beach dated at 2.6 and 2 cal ka BP in other sectors of the SSI and the highest raised beach of +15-17 m a.s.l., which was dated at 7.4 cal ka BP in different areas of this archipelago (Fig. 11).

The ages of glacial boulders prove the existence of a neoglacial advance in the Byers Peninsula occurred ~4 ka. Until now, no such advance had been proposed, although [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF] related the 10 m raised beach to a cold period with abundant rich icerafted debris, and [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF] proposed the same for the 10-12 m a.s.l. raised beach existing in the Hurd Peninsula. Previous studies proposed that the glacier fronts in the Byers Peninsula, as well as in the rest of the SSI, were approximately at their present-day position by 5.5 ka [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF][START_REF] Mäusbacher | Evolution of postglacial sedimentation in Antarctic lakes (King George Island)[END_REF][START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF][START_REF] Björck | Palaeoclimatic studies in South Shetlands Islands, Antarctica, based on numerous stratigraphic variables in lake sediments[END_REF][START_REF] Björck | Holocene glacial chronology from lake sediments[END_REF][START_REF] Mäusbacher | Die jungquartäre Relief-und Klimageschichte im Bereich der Fildeshalbinsel Su¨d-Shetland-Inseln[END_REF][START_REF] Valle | Mid-Holocene macrofossil-bearing raised marine beaches at Potter Peninsula, King George Island, South Shetland Islands[END_REF][START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF][START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Watcham | A new Holocene relative sea level curve for the South Shetland Islands, Antarctica[END_REF]Simms et al., 2011a and2012;[START_REF] Toro | Chronostratigraphy of the sedimentary record of Limnopolar Lake, Byers Peninsula, Livingston Island, Antarctica[END_REF][START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF]. Our results highlight the occurrence of a limited neoglacial advance at ~4

ka not exceeding 200 m from the present-day glacier front. Consequently, due to the small extent of this neoglacial expansion, it may have not been detected yet in other areas. There is evidence of a cold period in the SSI before 4 ka according to the analysis of lake [START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF] and marine sediments [START_REF] Milliken | High-resolution Holocene climate record from Maxwell Bay, South Shetland Islands, AntarcticaHolocene climate record from Maxwell Bay[END_REF][START_REF] Chu | Depositional environment and climate changes during the Holocene in Grande Valley, Fildes Peninsula, King George Island, Antarctica[END_REF]. In the context of the entire AP area and the rest of the continent, as discussed above, there is robust paleoenvironmental evidence that colder conditions with neoglacial associated advances occurred around 5 ka and were interrupted by the thermal maximum around 4-3 ka [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF][START_REF] Mosley-Thompson | Holocene climate changes recorded in an East Antarctica ice core. Climatic variations and forcing mechanisms of the last 2,000[END_REF][START_REF] Ingólfsson | Antarctic glacial history since the Last Glacial Maximum: an overview of the record on land[END_REF][START_REF] Ingólfsson | Glacial and climate history of the Antarctic Peninsula since the Last Glacial Maximum[END_REF][START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF][START_REF] Heroy | Holocene climate change in the Bransfield Basin, Antarctic Peninsula: evidence from sediment and diatom analysis[END_REF]Bentley et al., 2009;[START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF][START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF][START_REF] Carrivick | Late Holocene changes in character and behaviour of land-terminating glaciers on James Ross Island, Antarctica[END_REF]Cofaigh et al., 2014[START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF][START_REF] Davies | Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula[END_REF][START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF] (Fig. 11).

The last set of glacial landforms corresponds to the moraine ridges of the Rotch Dome Glacier on the southern flank of Clark Nunatak. This is the only area where the glacier is now spatially disconnected from the moraine and includes evidence of a Late Holocene advance of the glacier around the nunatak. Till and disperse erratic boulders are distributed on the 4-6 m a.s.l. raised beach. The BYC-4 and 5 samples were taken from the highest and most stable sector of the moraine showing an average age of ~1. ka.

Although, to date, a similar advance has not been confirmed during this time in the SSI, there is some sedimentological evidence pointing to that fact. [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF] suggested two neoglacial advances at 3 and 1 cal ka BP in the SSI. [START_REF] Björck | A late Holocene lake sediment sequence from Livingston Island, South Shetland Islands, with palaeoclimatic implications[END_REF] proposed a cold period in the Byers Peninsula between 1.5 and 0.5 cal ka BP. [START_REF] Hall | Variations in ice rafted detritus on beaches in the South Shetland Islands: a possible climate proxy[END_REF] delimited two cold periods at 0.25 and 1.7 cal ka BP. [START_REF] Hall | Holocene glacial history of Antarctica and the sub-Antarctic islands[END_REF] used the CRE 10 Be methodology to date moraines in the Hurd Peninsula and Marion Cove to 1.5-1.0 ka (Hall and Stone, personal communications). Simms et al. (2011a) indicated a neoglacial advance that ended at approximately 1.7 cal ka BP in Maxwell Bay (King George Island). Lake Domo, which is very close to the study area and located only 350 m from the present-day glacier front, was deglaciated around 1.8 cal ka BP, probably after a neoglacial advance [START_REF] Oliva | The Holocene deglaciation of the Byers Peninsula (Livingston Island, Antarctica) based on the dating of lake sedimentary records[END_REF]. [START_REF] Chu | Depositional environment and climate changes during the Holocene in Grande Valley, Fildes Peninsula, King George Island, Antarctica[END_REF] proposed the onset of neoglacial advances in the Fildes Peninsula at 2.7 cal ka BP. As discussed before, plentiful evidence from the AP confirm the occurrence of glacial advances between 2.8 and 1.4 ka [START_REF] Mosley-Thompson | Holocene climate changes recorded in an East Antarctica ice core. Climatic variations and forcing mechanisms of the last 2,000[END_REF][START_REF] Björck | Late Holocene palaeoclimatic records from lake sediments on James Ross Island, Antarctica[END_REF][START_REF] Khim | Unstable climate oscillations during the late Holocene in the eastern Bransfield Basin, Antarctic Peninsula[END_REF][START_REF] Heroy | Holocene climate change in the Bransfield Basin, Antarctic Peninsula: evidence from sediment and diatom analysis[END_REF]Bentley et al., 2009;[START_REF] Yoon | Late Holocene cyclic glaciomarine sedimentation in a subpolar fjord of the South Shetland Islands, Antarctica, and its paleoceanographic significance: sedimentological, geochemical, and paleontological evidence[END_REF][START_REF] Domack | Chronology of the Palmer Deep site, Antarctic Peninsula: A Holocene palaeoenvironmental reference for the circum-Antarctic[END_REF][START_REF] Strelin | New data related to Holocene landform development and climatic change from James Ross Island, Antarctic Peninsula[END_REF][START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF][START_REF] Davies | Antarctic Peninsula ice sheet evolution during the Cenozoic Era[END_REF][START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Shevenell | Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula[END_REF][START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF][START_REF] Abram | Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century[END_REF][START_REF] Hodgson | Late Quaternary environmental changes in Marguerite Bay, Antarctic Peninsula, inferred from lake sediments and raised beaches[END_REF][START_REF] Barnard | Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula[END_REF][START_REF] Davies | Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula[END_REF][START_REF] Čejka | Timing of the Neoglacial onset on the north-eastern Antarctic Peninsula based on lacustrine archive from Lake Anónima, Vega Island[END_REF][START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF] (Fig. 11).

As in previous glacial landforms, the ages of the moraine boulder (~1.0 ka) contradict the age of the raised beach where they rest (LIA). In fact, this raised beach at about 6 m a.s.l.

has been dated in the Byers Peninsula and other islands as belonging to the LIA, between approximately the 13 and 17th centuries AD [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF][START_REF] John | Evidence from the South Shetland Islands towards a glacial history of West Antarctica[END_REF][START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF][START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF][START_REF] Sugden | Glacial history of the Antarctic Peninsula and South Georgia[END_REF][START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF][START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF]Simms et al., 2011a and2012) (Fig. 11).

The only place where a moraine similar to the one studied in this work has been directly dated in the SSI was the Collins Glacier moraine in the Fildes Peninsula by [START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF], according to radiocarbon ages of mosses incorporated into the interior of the moraine. As in our study area, this sector of moraine was almost the only area where the moraine was separated from the present Collins Glacier front, and was also at a distance of about 500 m. The first results of this work indicated that the most external advance was 2.8 to 1 cal ka BP, although [START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF] discards this possibility, precisely because the moraine rests on the 6 m a.s.l. beach.

The discordance between the ages of the moraines dated by CRE ages and the ages of raised beaches provided by radiocarbon dating of organic fragments present in their sands will remain a topic of debate until we directly date the studied raised beaches instead of basing their age on a simple correlation of altitudes. This approach could lead to important errors related to the regional variability and local neo-tectonics [START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF][START_REF] Fretwell | Holocene isostatic uplift of the South Shetland Islands, Antarctic Peninsula, modelled from raised beaches[END_REF][START_REF] Simms | Late Holocene relative sea levels near Palmer Station, northern Antarctic Peninsula, strongly controlled by late Holocene ice-mass changes[END_REF].

The results suggest that these younger moraines may be somewhat older than the LIA, as previously thought [START_REF] Everett | Observations on the glacial history of Livingston Island[END_REF][START_REF] John | Raised marine features and phases of glaciation in the South Shetland Islands[END_REF][START_REF] John | Evidence from the South Shetland Islands towards a glacial history of West Antarctica[END_REF][START_REF] Sugden | The ages of glacier fluctuations in the South Shetland Islands, Antarctica[END_REF][START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF][START_REF] Sugden | Glacial history of the Antarctic Peninsula and South Georgia[END_REF][START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF][START_REF] Hall | Late-Holocene advance of the Collins Ice Cap, King George Island, South Shetland Islands[END_REF][START_REF] Hall | Holocene relative sea-level changes and ice fluctuations in the South Shetland Islands[END_REF]. Our proposal is that they are polygenic moraines formed by several neoglacial advances driven by cold periods that may have expanded from 2 ka to the LIA, as has been proposed in many other areas of the AP [START_REF] Zale | Lake sediment cores from the Antarctic Peninsula and surrounding islands[END_REF][START_REF] Domack | Chronology of the Palmer Deep site, Antarctic Peninsula: A Holocene palaeoenvironmental reference for the circum-Antarctic[END_REF][START_REF] Hall | Holocene history of the Wilson Piedmont Glacier along the southern Scott Coast[END_REF][START_REF] Allen | A record of Holocene glacial and oceanographic variability in Neny Fjord, Antarctic Peninsula[END_REF][START_REF] Storey | Cosmogenic nuclide exposure age constraints on the glacial history of the Lake Wellman area, Darwin Mountains, Antarctica[END_REF][START_REF] Michalchuk | Holocene climate and glacial history of the northeastern Antarctic Peninsula: the marine sedimentary record from a long SHALDRIL core[END_REF][START_REF] Balco | Exposure-age record of Holocene ice sheet and ice shelf change in the northeast Antarctic Peninsula[END_REF][START_REF] Davies | Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula[END_REF][START_REF] Davies | Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula[END_REF]. In fact, although the outermost crest of the moraine dates back to ~1.0 ka, based on our results (Fig. 4), the glacier must have retreated from the moraine limits very recently, probably after 1950, as occurred in the nearby peninsula of Elephant Point [START_REF] Oliva | Conceptualization[END_REF]Ruiz-Fernández, 2015, 2017) (Fig. 11).

The available proxy data for the Mid and Late Holocene does not yet allow to constrain which climate parameters are responsible for such glacial oscillations. Bentley et al. (2009) provided evidence of the occurrence of relative warmth from 4.5 to 2 cal. ka BP in the AP region, which is also confirmed by ice core records from the NE corner of the AP reporting relative stable temperature until 2.5 ka BP when climate cooled [START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history[END_REF]. Past surface air temperature changes are similar to those inferred from several sites across the AP from moss banks [START_REF] Charman | Spatially coherent late Holocene Antarctic Peninsula surface air temperature variability[END_REF].

The Neoglaciation of the SSI and the AP in a global context

Despite significant regional variations in the timing of Neoglaciation in the AP, there are some common patterns in all records: the end of maximum deglaciation occurred at around 7-6 ka and the first neoglacial started at 5 ka, with new and previously undated neoglacial advances between 2.7 and 1 ka, and even up to the LIA, before the RRW. Most records in the SSI are not concurrent with neoglacial timing in the AP. This can be related to the different nature of the records and dating methods used in each study. In fact, each of the proxies examined in this work (ice core, marine and lake sediments, raised beaches and glacial landforms) as well as the dating methods have been substantially refined over the last years and inter-comparisons between areas and methods are needed to homogenize and compare results (e.g. [START_REF] Simonsen | East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat[END_REF][START_REF] Singer | Synchronizing volcanic, sedimentary, and ice core records of Earth's last magnetic polarity reversal[END_REF][START_REF] Sadatzki | Sea ice variability in the southern Norwegian Sea during glacial Dansgaard-Oeschger climate cycles[END_REF][START_REF] Čejka | Timing of the Neoglacial onset on the north-eastern Antarctic Peninsula based on lacustrine archive from Lake Anónima, Vega Island[END_REF]. However, our data show that the chronology inferred directly from glacial landforms shows a similar timing for neoglacial advances in the SSI and the AP. Recently, [START_REF] Kaplan | Holocene glacier behavior around the northern Antarctic Peninsula and possible causes[END_REF] highlighted synchronous millennial-scale neoglacial oscillations in the NE edge of the AP and in Patagonia. These authors proposed that these neoglacial advances coincided with negative phases of the Southern Annular Mode (SAM), when the westerly winds expanded towards the equator. In line with this, the current RRW coincides with a positive phase of the SAM that is favoring widespread glacial retreat in both regions [START_REF] Abram | Evolution of the southern annular mode during the past millennium[END_REF].

The comparison of Neoglaciation in the AP with the Arctic records may reveal whether neoglacial advances follow interhemispheric connection between polar regions.

However, neoglacial advances within the Arctic show a very different pattern, even more divergent than within the AP [START_REF] Solomina | Holocene glacier fluctuations[END_REF][START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF]. Throughout the Arctic, the end of deglaciation varied from 11 to 5 ka depending on the region [START_REF] Renssen | Global characterization of the Holocene thermal maximum[END_REF]. The first phases of neoglacial advances were detected between 9 to 7 ka in Scandinavia and 4 ka in Greenland [START_REF] Solomina | Holocene glacier fluctuations[END_REF][START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF].

In any case, there are also some common patterns for the entire Arctic, which are quite similar to those observed in the AP. According to the most recent synthesis, glaciers retreated throughout the Arctic from 8.6 to 5 ka [START_REF] Marcott | A reconstruction of regional and global temperature for the past 11,300 years[END_REF][START_REF] Solomina | Holocene glacier fluctuations[END_REF][START_REF] Kaufman | Holocene climate changes in eastern Beringia (NW North America)-A systematic review of multi-proxy evidence[END_REF][START_REF] Sejrup | North Atlantic-Fennoscandian Holocene climate trends and mechanisms[END_REF][START_REF] Briner | Holocene climate change in Arctic Canada and Greenland[END_REF][START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF][START_REF] Geirsdóttir | The onset of neoglaciation in Iceland and the 4.2 ka event[END_REF], similarly to what happened in the SSI and the AP. After this widespread retreat, there are two main phases of generalized neoglacial expansion in (almost) all regions across the Arctic, one beginning at 4.5 ka and another from 2 ka to the LIA [START_REF] Solomina | Holocene glacier fluctuations[END_REF][START_REF] Miller | Unprecedented recent summer warmth in Arctic Canada[END_REF][START_REF] Miller | Episodic Neoglacial snowline descent and glacier expansion on Svalbard reconstructed from the 14C ages of ice-entombed plants[END_REF][START_REF] Mckay | The onset and rate of Holocene Neoglacial cooling in the Arctic[END_REF][START_REF] Geirsdóttir | The onset of neoglaciation in Iceland and the 4.2 ka event[END_REF]. A similar timing for glacial advances was also identified in the SSI and the AP.

Therefore, there is a common global pattern at a millennia timescale with regards to the Neoglaciation dynamics in glaciers of the AP and in the Arctic. These patterns are similar to those found in the Byers Peninsula: intensive deglaciation around 8.6 to 5 ka, followed by the first neoglacial advances around 4.5 ka and new, intensive neoglacial advances around 2 ka. This Late Holocene glacier behavior in the high latitudes of both hemispheres is very different from the evolution of temperatures that occurred in the two regions during Termination I, when temperature changes were simultaneous but inverse in the two hemispheres, the pattern known as "bipolar seesaw" [START_REF] Broecker | The role of ocean-atmosphere reorganizations in glacial cycles[END_REF][START_REF] Barker | Interhemispheric Atlantic seesaw response during the last deglaciation[END_REF][START_REF] Barker | Extreme deepening of the Atlantic overturning circulation during deglaciation[END_REF]. The opposite temperature trends recorded in Antarctica and Greenland during Termination I (seesaw pattern) have been confirmed by ice cores [START_REF] Severinghaus | Abrupt climate change at the end of the last glacial period inferred from trapped air in polar ice[END_REF][START_REF] Brook | Antarctic and global climate history viewed from ice cores[END_REF][START_REF] Stolper | Pleistocene ice core record of atmospheric O2 concentrations[END_REF] and are attributed to changes in the intensity of the Atlantic Meridional Overturning Circulation (AMOC, Baker et al., 2009, 2010). The cooling of the Northern Hemisphere reduces the strength of the AMOC [START_REF] Deaney | Timing and nature of AMOC recovery across Termination 2 and magnitude of deglacial CO 2 change[END_REF][START_REF] Muschitiello | Deep-water circulation changes lead North Atlantic climate during deglaciation[END_REF], which, in turn, causes the ventilation of the Southern Hemisphere oceans and the emission of a large amount of CO 2 into the atmosphere, significantly warming Antarctica [START_REF] Ahn | Abrupt change in atmospheric CO2 during the last ice age[END_REF][START_REF] Beeman | Antarctic temperature and CO2: Near-synchrony yet variable phasing during the last deglaciation[END_REF][START_REF] Clementi | Southwest Pacific vertical structure influences on oceanic carbon storage since the Last Glacial Maximum[END_REF]. Inverse temperatures between the two hemispheres during Termination I resulted in opposite behavior of the glaciers in each hemisphere [START_REF] Jomelli | A major advance of tropical Andean glaciers during the Antarctic cold reversal[END_REF][START_REF] Darvill | The timing and cause of glacial advances in the southern mid-latitudes during the last glacial cycle based on a synthesis of exposure ages from Patagonia and New Zealand[END_REF][START_REF] Koffman | A beryllium-10 chronology of late-glacial moraines in the upper Rakaia valley, Southern Alps, New Zealand supports Southern-Hemisphere warming during the Younger Dryas[END_REF][START_REF] Shulmeister | The timing and nature of the last glacial cycle in New Zealand[END_REF]. However, this was not the case during the Holocene, mainly during Neoglaciation. The orbitally-forced changes in insolation are likely to be the main driver of Neoglaciation. In fact, negative Total Solar Irradiance anomalies are proposed as one of the main triggers of neoglacial advances into the large scale climatic transformations (Renssen 2006;Solomina et al., 2012), together with volcanic activity, which also played an important role in some of the neoglacial events [START_REF] Miller | Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks[END_REF][START_REF] Miller | Unprecedented recent summer warmth in Arctic Canada[END_REF]. Both the HTM and the Neoglaciation are global-scale patterns, despite recording notable regional variability. This could be the critical difference with the current warm period (RRW),

where the response of glaciers is almost global and synchronous [START_REF] Renssen | Global characterization of the Holocene thermal maximum[END_REF]Solomina et al., 2012).

Conclusions

Establishing the chronology of deglaciation of ice-free areas in the AP region is of key importance in a changing climate scenario. To that purpose, we have reconstructed the calendar of the most recent glacial oscillations in the largest ice-free area in the SSI, the Byers Peninsula. Here, previous knowledge on the deglaciation was based on only a few radiocarbon dates from lake sediments that did not offer an accurate picture of the glacial evolution of the Mid-Late Holocene. We used CRE dating to examine the timing of neoglacial advances of Rotch Dome Glacier and compare it with other areas across the AP region.

Deglaciation of today's main ice-free areas in the SSI and the rest of the AP occurred between 9 and 6 ka, according to previous studies. After 6 ka, glaciers were similar or smaller than their present-day size in most of the AP. The first neoglacial advance in this area took place from ~5.5 ka, followed by a warm period between 4 and 2.8 ka.

Subsequently until 1.0 ka, there was another period of generalized neoglacial advance in the AP. In the SSI, there was evidence of cold periods from 5.8 to 5.6, and from 2.7 cal ka BP from some paleoclimatic proxies, but the glacial response to those climate shifts was still unknown. This study confirms that, as in other areas of the AP, glacial advances also occurred in the SSI during these Neoglaciation cold periods in ~4.1 and 1.0 ka.

The recent synthesis of glacial evolution in the Arctic since the Mid-Holocene shows that there was even larger regional diversity with regards to the chronology of neoglacial advances. In the Arctic, the regional climate forcings determine climate trends that can

  docx [Conflict of Interest] CRediT author statement.docx [Author Statement]

  lead to glacial advance within a global tendency to warming. However, millennial-scale patterns between the Arctic and the AP region seem to follow common trends. This timing revealed by the neoglacial landforms should be taken into account when looking for the origin of climate changes that caused Neoglaciation, which was practically synchronous in both polar areas. Consequently, although the objective of this work was not to examine the origin and causes of Neoglaciation, we provide new evidence supporting a global background for neoglacial advances beyond hemispheric-scale factors, which would have favored neoglacial advances with different time ranges in both Polar Regions. en Provence), which is supported by the INSU/CNRS and the ANR through the "Projets thématiques d'excellence" program for the "Equipements d'excellence" ASTER-CEREGE action and IRD. David Palacios thanks to the Institute of Alpine and Arctic Research, at the University of Colorado, the facilities provided to coordinate this work during his Fulbright Grant stay there in 2019. Marc Oliva is supported by the Ramón y Cajal Program (RYC-2015-17597) and the Research Group ANTALP (Antarctic, Arctic, Alpine Environments; 2017-SGR-1102). We thank Dr. Vincent Jomelli, Dr. Jan-Hendrik May one anonymous reviewers for their valuable suggestions that have greatly improved the paper.

Figure captions Figure 1 .

 captions1 Figure captionsFigure 1. Location of areas cited in the text related to Antarctica. A) Antarctic Ice Sheet; B) Ross Ice Shelf; C) Antarctic Peninsula; D) Graham Land. This figure is available in colour in the online version.

Figure 2 .

 2 Figure 2. Location of the areas cited in the text. A) South Shetland Islands; B) Hurd Peninsula; C) Fildes and Barton peninsulas; D) Byers Peninsula. This figure is available in colour in the online version.

Figure 3 .

 3 Figure 3. Probability density plots of CRE ages for differentiated chronostratigraphical units: A) Deglaciation, b) First Neoglacial advance and c) Second Neoglacial advance. This figure is available in colour in the online version.

Figure 4 .

 4 Figure 4. Location of the study area, with the main geomorphological features, CRE samples and their ages plotted in a Google Earth satellite image. This figure is available in colour in the online version.

Figure 5 .

 5 Figure 5. Geomorphological sketch with CRE arithmetic mean ages for each geomorphological unit. This figure is available in colour in the online version.

Figure 6 .

 6 Figure 6. Geomorphological transect of the main features with arithmetic mean of the CRE ages in each unit. This figure is available in colour in the online version.

Figure 7 .

 7 Figure 7. BYC-1 and -2 samples and CRE ages in Rish Point, Byers Peninsula. This figure is available in colour in the online version.

Figure 8 .

 8 Figure 8. BYC-11 and -12 and BYB-10 samples and CRE ages on South Beaches area, Byers Peninsula. This figure is available in colour in the online version.

Figure 9 .

 9 Figure 9. BYC-12 and -13 samples and CRE ages in front of Rish Point, Byers Peninsula. This figure is available in colour in the online version.

Figure 10 .

 10 Figure 10. BYC-4 and -5 samples and CRE ages in the moraine between Rish Point and Clark Nunatak, Byers Peninsula. This figure is available in colour in the online version.

Figure 11 .

 11 Figure 11. Summary table comparing the timing of neoglacial expansion in the AP region and the results of this work. This figure is available in colour in the online version.

  2. The paper presents a relatively small dataset of new results but compensates by constructing a detailed framework for interpretation by reviewing a large amount of available literature. I am aware that -as indicated by the title, and re-emphasized in lines 794-795 -you are trying to avoid an in-depth discussion of climatic drivers for glacial advances. However, in my personal opinion if you compare your and other existing data from Antarctic to the Arctic, I would think that you need to provide (at least a short, i.e. a few sentences) discussion of reasons and mechanisms for these global scale controls. How does this work? What are the mechanisms? Is this related to global insolation changes over millennial scales, and thereby global air temperature? How does this relate to the atmospheric and oceanic circulations? And what are the implications with regard to the RRW (i.e. can you come back to your introduction)?

  The ice-free area of the Byers Peninsula is delimited in its eastern flank by the Dome Rotch Glacier, which covers the rest of the western part of Livingston Island reaching a maximum altitude of 360 m. Although there is no information about the recent evolution of Dome Rotch Glacier in the side of the Byers Peninsula, significant retreat has been observed in other neighbouring coastal fringes since the 1950s

	of volcanic plugs such as Start Hill (265 m a.s.l.), Chester Cone (188 m), Cerro Negro
	(143 m), Tsamblak Hill (113 m) and Clark Nunatak (147 m). Many lakes are distributed
	on this plateau, such as the Limnopolar, Chester, Escondido, Cerro Negro and Domo lakes
	(Fig. 2, Table 3). This central plateau is encircled by an intermediate marine platform (50-
	80 m) that is surrounded by a lower platform above which Holocene raised beaches from
	2 to 15-16 m a.s.l have developed. The sequence of raised beaches is particularly well-
	preserved in the South beaches (S), the Robbery beaches (N), and the President beaches
	(W).

is formed by a high plateau (80-110 m), considered a marine platform, onto which protruded a series

Table 6

 6

). Compositional analyses of all aliquots were performed at the "Service d'Analyse des Roches et des Minéraux" (SARM, CRPG, Nancy, France). Before total dissolution, ~260 μL of a 35 Cl carrier (spike: 010813(4), 6.92 mg Cl g -1 , 35 Cl/ 37 Cl ratio 917.75) manufactured in-house were added to the samples for isotopic dilution

[START_REF] Ivy-Ochs | Initial results from isotope dilution for Cl and 36Cl measurements at the PSI/ETH Zurich AMS facility[END_REF]

, allowing for simultaneous determination of the 36 Cl and Cl concentrations from the 36 Cl/ 35 Cl and

35

Cl/ 37 Cl measurements. For the total dissolution of the rock samples, a mixture of 9 mL of 10% HNO 3 per gram of sample and 4.5 mL of 48% HF per gram of sample was used.

Table captions Table 1 .

 captions1 Timing of Neoglacial advances in the AP region.

Table 2 .

 2 Timing of the end of deglaciation and geomorphic evidence of Neoglacial advances in the SSI.

Table 3 .

 3 End of deglaciation, Neoglacial evidence and related features in the ByersPeninsula.

Table 4 .

 4 Geographic location of samples, topographic shielding factor, sample thickness and distance from terminus.

Table 5 .

 5 Chemical composition of the bulk rock samples before chemical treatment. The data in italics correspond to the average values of the element concentrations of the samples BYC-2, BYC-4, BYC-11 (included in this studio) and others of similar lithology collected in nearby areas, but not included in this study. These average values have been used for the age-exposure calculations of those samples without bulk chemical composition analysis.

Table 6 .

 6 Concentrations of the major elements determined in splits taken after the

Table 6 .

 6 Concentrations of the major elements determined in splits taken after the chemical pre-treatment (acid etching). P 2 O 5 concentrations are below detection limit (0.015%).

	Sample name CaO (%)	K 2 O (%)	TiO 2 (%)	Fe 2 O 3 (%)	SiO 2 (%)	Al 2 O 3 (%)	MnO (%)	MgO (%)	Na 2 O (%)
	BYC-1	8.99 ± 0.45	0.40 ± 0.10	0.78 ± 0.16	10.21 ± 0.20	55.49 ± 1.11	14.37 ± 0.29	0.19 ± 0.04	4.38 ± 0.44	8.99 ± 0.29
	BYC-2	8.06 ± 0.40	0.39 ± 0.10	1.07 ± 0.11	10.71 ± 0.21	58.03 ± 1.16	13.45 ± 0.27	0.19 ± 0.04	3.86 ± 0.39	8.06 ± 0.30
	BYC-3	8.15 ± 0.41	0.43 ± 0.11	1.40 ± 0.14	10.54 ± 0.21	57.13 ± 1.14	13.24 ± 0.26	0.18 ± 0.04	4.67 ± 0.47	8.15 ± 0.27
	BYC-4	8.21 ± 0.41	0.49 ± 0.12	0.74 ± 0.15	9.30 ± 0.93	56.98 ±1.14	14.41 ±0.29	0.17 ± 0.03	4.01 ± 0.40	8.21 ± 0.33
	BYC-5	8.20 ± 0.41	0.41 ± 0.04	0.87 ± 0.17	10.70 ± 0.21	57.04 ±1.14	13.35 ± 0.27	0.20 ± 0.04	4.53 ± 0.45	8.20 ± 0.30
	BYC-9	8.71 ± 0.44	0.29 ± 0.07	1.22 ± 0.12	11.03 ± 0.22	57.09 ± 1.14	11.31 ± 0.23	0.20 ±0.04	5.75 ± 0.12	2.27 ± 0.23
	BYC-10	7.51 ± 0.38	0.49 ± 0.12	1.19 ± 0.12	8.77 ± 0.88	61.48 ± 1.23	10.86 ± 0.22	0.16 ± 0.03	4.51 ± 0.45	2.00 ± 0.20
	BYC-11	8.35 ± 0.42	0.35 ± 0.09	1.22 ± 0.12	10.00 ± 1.00	57.42 ±1.15	11.45 ± 0.23	0.18 ± 0.04	5.46 ± 0.11	2.07 ± 0.21
	BYC-13	8.22 ± 0.41	0.49 ± 0.12	1.04 ± 0.10	9.67 ± 0.97	57.94 ± 1.16	12.55 ± 0.25	0.18 ± 0.04	4.84 ± 0.48	2.39 ± 0.24
	BYC-14	8.75 ± 0.44	0.32 ± 0.08	1.27 ± 0.13	10.70 ± 0.21	57.05 ± 1.14	11.84 ± 0.24	0.19 ± 0.04	5.58 ± 0.11	2.23 ± 0.22

Table 7 .

 7 AMS analytical data and calculated exposure ages.36 Cl/ 35 Cl,35 Cl/ 37 Cl and 10 Be/ 9 Be ratios were inferred from measurements at the ASTER AMS facility. The numbers in italics correspond to the internal (analytical) uncertainty at one standard deviation. Note that the 36 Cl ages reported for "St" scaling were calculated through the Excel™ spreadsheet by[START_REF] Schimmelpfennig | Sources of in-situ 36Cl in basaltic rocks. Implications for calibration of production rates[END_REF] and those for "LSD" scaling were calculated through the trial version of the CREp online calculator[START_REF] Schimmelpfennig | The CREp Chlorine-36 exposure age and depth profile calculator[END_REF].

	36 Cl samples
	Sample name	Sample weight (g)	mass of Cl in	35 Cl/ 37 Cl	36 Cl/ 35 Cl (10 -14 )	[Cl] in sample	[ 36 Cl] (10 4 atoms g -1 ) Age (ka)	Age (ka)
			spike (mg)			(ppm)		"St" scaling	"LSD" scaling
	BYC-1	78.58	1.821	13.808 ± 0.231	11.015 ± 0.702	8.8	5.54 ± 0.37	11.0 ± 1.4 (1.0)	10.4 ± 1.2 (0.7)
	BYC-2	76.22	1.777	7.833 ± 0.138	8.731 ± 0.681	20.4	5.70 ± 0.47	11.0 ± 1.5 (1.2)	10.3 ± 1.3 (1.0)
	BYC-3	66.44	1.809	13.201 ± 0.220	8.028 ± 0.575	10.9	4.79 ± 0.36	9.7 ± 1.2 (1.0)	9.1 ± 1.1 (0.8)
	BYC-4	75.32	1.807	8.490 ± 0.142	1.207 ± 0.197	18.3	0.68 ± 0.13	1.2 ± 0.3 (0.3)	1.1 ± 0.3 (0.2)
	BYC-5	75.46	1.811	10.409 ± 0.171	1.093 ± 0.176	13.4	0.53 ± 0.11	1.0 ± 0.2 (0.2)	0.8 ± 0.2 (0.2)
	BYC-9	74.98	1.819	3.962 ± 0.066	1.927 ± 0.263	120.8	3.69 ± 0.59	3.4 ± 0.8 (0.7)	3.0 ± 0.7 (0.6)
	BYC-10	68.10	1.814	25.547 ± 0.495	3.983 ± 0.390	4.6	1.95 ± 0.21	4.4 ± 0.7 (0.6)	4.2 ± 0.6 (0.4)
	BYC-11	67.49	1.821	6.966 ± 0.121	2.753 ± 0.330	29.0	2.19 ± 0.29	3.9 ± 0.7 (0.6)	3.6 ± 0.6 (0.5)
	BYC-13	70.44	1.819	19.341 ± 0.347	4.606 ± 0.422	6.3	2.32 ± 0.23	5.0 ± 0.7 (0.6)	4.7 ± 0.6 (0.5)
	BYC-14	69.89	1.799	5.217 ± 0.088	2.623 ± 0.335	51.0	2.77 ± 0.39	4.0 ± 0.8 (0.7)	3.6 ± 0.7 (0.6)
	36 Cl Blanks					Total atoms Cl	Total atoms 36 Cl
						(10 17 )	(10 4 )
	BL-1	-	1.805	353.174 ± 11.131	0.265 ± 0.073	2.252 ± 0.160	8.264 ± 2.264	-	-
	BL-5	-	1.822	362.525 ± 8.014	0.290 ± 0.075	2.177 ± 0.133	9.133 ± 2.377	-	-
	10 Be samples
	Sample name	Quartz weight (g)	mass of carrier		10 Be/ 9 Be (10 -14 )		[ 10 Be] (10 4 atoms g -		Age (ka)
			( 9 Be mg)				1 )
	BYC-12	64.5799	152.29		5.644 ± 0.286		2.701 ± 0.137		5.5 ± 0.4 (0.3)
	BYB-10	82.2924	151.98		4.719 ± 0.496		1.762 ± 0.185		3.5 ± 0.4 (0.4)
	10 Be Blank
	BYB-BK	-	151.29			-	-	-	-

Cl measurements were performed at the ASTER AMS national facility (CEREGE, Aix

Acknowledgements

This paper was supported by the projects CTM2016-77878-P and CGL2015-65813-R (Spanish Ministry of Economy and Competitiveness), and NUNANTAR (02/SAICT/2017 -32002; Fundação para a Ciência e a Tecnologia, Portugal). It also complements the research topics examined in the project PALEOGREEN (CTM2017-87976-P; Spanish Ministry of Economy and Competitiveness). We also thank the Portuguese Polar Program for their support in organizing field logistics. The 10 Be and

chemical pre-treatment (acid etching). P 2 O 5 (%) concentrations are below detection limit (0.10 ± 0.015).

Table 7. AMS analytical data and calculated exposure ages. 36 Cl/ 35 Cl, 35 Cl/ 37 Cl and 10 Be/ 9 Be ratios were inferred from measurements at the ASTER AMS facility. The numbers in italics correspond to the internal (analytical) uncertainty at one standard level. [START_REF] Barsch | New data on the relief development of the South Shetland Islands, Antarctica[END_REF][START_REF] Mäusbacher | Die jungquartäre Relief-und Klimageschichte im Bereich der Fildeshalbinsel Su¨d-Shetland-Inseln[END_REF][START_REF] Valle | Mid-Holocene macrofossil-bearing raised marine beaches at Potter Peninsula, King George Island, South Shetland Islands[END_REF][START_REF] Hall | An overview of late Pleistocene glaciation in the South Shetland Islands[END_REF][START_REF] Bentley | Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula[END_REF]Hall, Occurrence of two glacial advances: (i) a 2-3 km long advance was dated at the 13th to early 15th CE related to the raised beach 6 m a.s.l., (ii) and another smaller glacial expansion of 0.25-1 km at the 16-17th CE related to raised beach 2-3 m a.s.l. [START_REF] Curl | A glacial history of the South Shetland Islands, Antarctica[END_REF][START_REF] Sugden | Glacial history of the Antarctic Peninsula and South Georgia[END_REF][START_REF] Clapperton | Holocene glacier fluctuations in South America and Antarctica[END_REF][START_REF] Birkenmajer | Raised marine features and glacial history in the vicinity of H. Arctowski Station, King George Island (South Shetland Islands, West Antarctica)[END_REF][START_REF] Birkenmajer | Glacier retreat and raised marine beaches at Three Sisters Point, King George Island (South Shetland Islands, West Antarctica)[END_REF][START_REF] Birkenmajer | Quaternary geology at Potter Peninsula, King George Island (South Shetland Islands, West Antarctica)[END_REF] Fildes Peninsula (King George Island)

Declaration of interests

☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: