Carole ; Nehme

Dominique ; Todisco

Sebastian F M ; Breitenbach

Isabelle ; Couchoud

Marta ; Marchegiano

Marion ; Peral

Hubert ; Vonhof

J ; Hellstrom

R ; Tjallingii

Philippe ; Claeys

L ; Borrero

F Martin

Holocene hydroclimate variability along the Southern Patagonian margin (Chile) reconstructed from Cueva Chica speleothems

come   L'archive ouverte pluridisciplinaire

3 cave and 9.4°C outside in summer and 2°C in winter (Suppl., fig. 2). The catchment area of the cave comprises hilly slopes covered by scattered trees of Nothofagus. Some areas are covered by open grassland and peat vegetation. It is noteworthy that the catchment of the cave is downstream the Vega Benitez peat bog [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF]. Fig. 1. Overview of southernmost Chile with the study site. A) Map of southernmost Chile with sites of discussed paleoclimate records: 1 -Marine cores GeoB3313-1 [START_REF] Lamy | High-and low-latitude climate control on the position of the southern Peru-Chile Current during the Holocene[END_REF] and ODP1233 [START_REF] Lamy | Glacial reduction and millennial-scale variations in Drake Passage throughflow[END_REF], 2 -lake Mallin Pollux [START_REF] Markgraf | Vegetation and fire history during the last 18,000 cal yr BP in Southern Patagonia: Mallín Pollux, Coyhaique, Province Aisén[END_REF]), 3 -Lago Argentino (Kaplan et al., 2016), 4 -Cerro Frias peat [START_REF] Tonello | Quantitative reconstruction of Holocene precipitation changes in southern Patagonia[END_REF], 5 -Lago Cipreses (Moreno et al., 2018), 6 -Vega Benitez peat (McCulloch et al., 2021), 7 -Chica cave (this study), 8 -Lago Eberhart peat [START_REF] Moreno | Deglacial changes of the southern margin of the southern westerly winds revealed by terrestrial records from SW Patagonia (52 S)[END_REF], 9 -Marcelo Arevalo (MA) cave [START_REF] Schimpf | The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies[END_REF]), 10 -GC peat bog (Killian et al., 2003;[START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF], 11 -lake Tamar [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF], 12 -lake Potrok Aike [START_REF] Schäbitz | Reconstruction of palaeoprecipitation based on pollen transfer functions-the record of the last 16 ka from Laguna Potrok Aike, southern Patagonia[END_REF], 13 -Pta Burselem & Isla Navarino peats (McCulloch et al., 2019;[START_REF] Daëron | Full Propagation of Analytical Uncertainties in Δ 47 Measurements[END_REF]. Latitudinal changes of average westerly wind intensities in summer and winter between 1960between & 2000 AD are AD are shown in yellow and blue (source: NCEP-NCAR). B) Annual precipitation over southernmost Chile [START_REF] Schneider | Weather observations across the southern Andes at 53°S[END_REF]. Insert shows an ombrothermal diagram of Puerto Natales (www.climate-data.org). C) Study area Cerro Benitez with caves (yellow stars) and peatbogs (blue circles) mentioned in this study. 3 Methods 3.1. Petrography Both S6 and S6bis cores and stalagmite S8 were cut along their growth axes, polished using 120-4000 μm silicon carbide sandpaper. Twelve thin sections (80-100 m thick) were prepared at the department for Sediment and Isotope Geology, Ruhr University Bochum, Germany. A petrographic analysis was conducted with a Leica optical microscope to determine the stratigraphical characteristics of core S6 (e.g., fabrics, structures, inclusions, discontinuities, hiatuses).

U-series and 14 C dating

Seventeen samples of between 30 and 230 mg were extracted from the sectioned cores S6 and S6bis and stalagmites S8 for U/Th dating using 0.5 to 0.8 mm tungsten carbide dental bits mounted on a Sherline 2010 micromill. Samples were dissolved in isolation using 1.5M HNO 3 , spiked with a measured quantity of 233 U- 229 Th or 236 U-233 U-229 Th mixed synthetic isotopic tracer [START_REF] Hellstrom | Rapid and accurate U/Th dating using parallel ion-counting multi-collector ICP-MS[END_REF][START_REF] Drysdale | Precise microsampling of poorly laminated speleothems for U-series dating[END_REF]

and allowed

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 4 to equilibrate on a hotplate overnight. U and Th were separated from the carbonate matrix using Eichrom TRU ion exchange resin and established methods [START_REF] Luo | High precision 230 Th/ 232 Th and 234 U/ 238 U measurements using energyfiltered ICP magnetic sector multiple collector mass spectrometry[END_REF], modified to collect U and Th in the same fraction using 0.1M HCl-0.2M HF [START_REF] Hellstrom | Rapid and accurate U/Th dating using parallel ion-counting multi-collector ICP-MS[END_REF]. Mass spectrometric analysis was undertaken at the University of Melbourne using either a Nu Instruments Plasma MC-ICP-MS with standard collector block or a similar instrument with modified collector block placing simultaneously using the high-and low-mass SEM ion counters in each case [START_REF] Hellstrom | Rapid and accurate U/Th dating using parallel ion-counting multi-collector ICP-MS[END_REF]. Ion counter gain was determined using ion counter and Faraday measurements of 235 U and 229 Th for the standard collector block and 236 U/ 233 U and 229 Th for the modified collector bloc mass bias was determined using the bulk earth natural 238 U/ 235 U ratio of 137.88, this technique being relatively insensitive to error in this ratio due to the simultaneous measurement of 229 Th/ 230 Th and 233 U/ 234 U. Ion counter baselines were measured at half mass units and interpolated for 234 U and 230 Th. Initial 230 Th/ 232 Th activities were determined by stratigraphic constraint [START_REF] Hellstrom | U-Th dating of speleothems with high initial 230 Th using stratigraphical constraint[END_REF] where possible, giving a value of 0.93 ± 0.08. An additional 14 C date was obtained through the analysis of 10 mg of charcoal sampled on core S6bis. The preparation and measurement were completed at the Radiochronology lab from Laval University, Québec, Canada. Radiocarbon concentrations are given as fractions of the modern standard,  14 C, and conventional radiocarbon age, following the conventions of [START_REF] Stuiver | Discussion reporting of 14 C data[END_REF]. Result was corrected for isotope fractionation according to the conventions of [START_REF] Stuiver | Discussion reporting of 14 C data[END_REF], with  13 C value measured on the graphite prepared, using the AMS spectrometer. Stratigraphic correspondence (Suppl., fig. 3) combined with U-Th dates from core S6bis permits the inclusion of the radiocarbon date into the age model, after the calibration (cal. BP) of the measured age (Suppl., fig. 5), using OxCal program [START_REF] Ramsey | Bayesian analysis of radiocarbon dates[END_REF] and the atmospheric data from [START_REF] Reimer | The IntCal20 Northern Hemisphere radiocarbon age calibration curve (0-55 cal kBP)[END_REF]. Age-depth models are based on COPRA [START_REF] Breitenbach | Constructing proxy records from age models (COPRA)[END_REF].

Calcite and water stable isotopes measurements

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 5 Stable isotope samples were taken along the growth axis of core S6 and stalagmite S8 (Fig. 2) for  13 C and  18 O measurements. Overall, 310 samples were measured in core S6 and 68 in stalagmite S8. Samples were drilled along the stalagmite growth axis at 1 mm resolution using a Merchantek Micromill mounted on a Leica microscope. Between every sample, the drill bit and sampling surface were cleaned with compressed air. In addition, two recent calcite samples underneath active drip water were collected nearby the sampling area and measured for  13 C and  18 O. The samples were analysed using a Nu Carb carbonate device coupled to a Nu Perspective mass spectrometer (MS) at the Vrije Universiteit Brussel, Belgium. Part of the samples were measured at the Sediment and Isotope Geology department, Ruhr University Bochum, Germany, using a Thermo Gasbench II connected to a Thermo MAT253 Plus MS in continuous flow mode. All  18 O and  13 C values are calibrated against Vienna Pee-Dee Belemnite (V-PDB) and are reported in permil (‰). Analytical uncertainties were better than 0.1 ‰ (1σ) for oxygen and 0.05 ‰ (1σ) for carbon on both instruments. Sixteen water samples were collected from the Cueva Chica and nearby caves, springs and lakes in December 2016, 2017, and 2018 for  18 O and D measurements in hermetically sealed glass bottles. Isotope measurements were performed at the Vrije Universiteit Brussel on a Picarro L2130-i analyzer using the cavity ring-down spectroscopy (CRDS) technique (Van Geldern and Barth Johannes, 2012). All values are reported in permil relative to Vienna Standard Mean Ocean Water (VSMOW). Analytical uncertainties (1σ) were better than 1 ‰ for D and 0.1 ‰ for  18 O.

μXRF element data

The elemental distribution of Ca and Sr has been determined in core S6 using a μX-ray fluorescence (μXRF) scanning. The scanning maps were selected along the stable isotope track using an Bruker M4 Tornado μXRF spectrometer at the GFZ (Potsdam, Germany). The μXRF is equipped with a 50W Rh X-ray source that was operated at 50 kV and 600 μA with a spot sizer of 20 µm. Measurements were performed under vacuum every 50 μm and a counting time of 25 ms. The resulting element intensities are given in counts per second (cps) and Sr element intensities were normalized over Ca to minimize sample density effects. The Sr/Ca ratios were scaled by multiplying the intensity ratios by 1000, and transferred on to the age scale though the age-depth model.

Fluid inclusions stable isotope (H-O) analyses

Fluid inclusion D and  18 O values from core S6 were obtained at the Max Planck Institute for Chemistry in Mainz, Germany. Nine samples, consisting of 1 to 2 chips (Suppl., fig. 7) weighing in total 0.6-0.8 g were placed in a crushing cell and pre-heated at 115°C in a moisturized nitrogen flow for 20 minutes before crushing. Liberated fluid inclusion water was analysed in a Picarro 2140i analyser. The contribution of the ~13000 ppm water background in the N2 carrier gas, which serves to remove sample-to-sample memory effects in this analytical system, is mathematically subtracted from the isotope values analysed for the crushed sample [START_REF] Affolter | New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)[END_REF][START_REF] Graaf | Fluid evolution & ore deposition in the Harz Mountains revisited: isotope & crush-leach analyses of fluid inclusions[END_REF]. A detailed description of the analytical technique as it is set up at MPIC can be found in De [START_REF] Graaf | Fluid evolution & ore deposition in the Harz Mountains revisited: isotope & crush-leach analyses of fluid inclusions[END_REF]. The Cueva Chica data were collected in two different series. For each series more than10 aliquots of standard water were injected in the crusher system, analysed identically to the crushed samples and reproduced within 0.09 ‰ for  18 O and 0.3 ‰ for D for both series (1σ). All fluid inclusion isotope data are reported on the VSMOW2-SLAP2 scale.

Clumped isotopes

Clumped isotope analyses were carried out at the AMGC laboratory of Vrije Universiteit Brussel (VUB), Belgium, using a Nu-Pespective-IS-IRMS combined with a Nu-Carb system. The full methodology for the Δ 47 analyses performed at the AMGC-VUB lab is described in De Vleeschouwer et al. (2022). A total of seven samples (Suppl., fig. 7) from core S6 were analysed and replicated 10 to 15 times (Suppl., table 2). For each analysis, a minimum of 500 g of carbonate was reacted at 70°C with H 3 PO 4 acid. Possible contaminations were tracked by scrutinising raw Δ 49 values of ETH1-4 standards for significant deviations from the mean [START_REF] Meckler | Long-term performance of the Kiel carbonate device with a new correction scheme for clumped isotope measurements[END_REF]. ETH standards were measured following the recommendations of [START_REF] Kocken | Optimizing the Use of Carbonate Standards to Minimize Uncertainties in Clumped Isotope Data[END_REF] with a sample to standard ratio of 1:1. Analyses were constantly monitored using the Easotope software [START_REF] John | Community software for challenging isotope analysis: First applications of 'Easotope'to clumped isotopes[END_REF]. The raw Δ 47 values were processed using the IUPAC isotopic parameters [START_REF] Brand | Correction for the 17 O interference in δ 13 C measurements when analyzing CO 2 with stable isotope mass spectrometry[END_REF][START_REF] Daëron | Absolute isotopic abundance ratios and the accuracy of Δ 47 measurements[END_REF][START_REF] Petersen | Effects of Improved 17O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral-Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation[END_REF] within the ClumpyCrunch software [START_REF] Daëron | Full Propagation of Analytical Uncertainties in Δ 47 Measurements[END_REF] and converted to the I-CDES 90°C scale [START_REF] Bernasconi | InterCarb: A community effort to improve interlaboratory standardization of the carbonate clumped isotope thermometer using carbonate standards[END_REF]. The  47 values were converted to temperatures using the regression of [START_REF] Anderson | A Unified Clumped Isotope Thermometer Calibration (0.5-1,100°C) Using Carbonate-Based Standardization[END_REF]. Temperature uncertainties were calculated by propagating the standard error (SE) for each sample and the uncertainties associated with the Electronic copy available at: https://ssrn.com/abstract=4172978 calibration. The ∆ 47 uncertainties (SE) are based on external ∆ 47 reproducibility of our analytical sessions of measurements, based on repeated analyses of standards and samples.

Results

Petrography

Petrographic analysis of thin sections (Suppl., fig. 2) shows that core S6 is mainly composed of columnar calcite, which ranges from poorly-to-well laminated to massive, often with a persistent component of detrital impurities. Based on clastic content, fabrics, and colour of the calcite, four main lithofacies are identified in core S6. From base to top (Fig. 2) we observe: i) Lithofacies Lf 4 , from 392 to 335 mm from top, rich in clastic material and characterised by yellowish calcite with poorly laminated and more porous structure embedded in a micro-gour structure. Lf 4 reveals a low but significant content of oxides, rutile and microcalcite fragments (e.g., micrite, sparite) filling the voids between the calcite crystals.

ii) Lithofacies Lf 3, from 335 to 98 mm, composed of compact, elongated columnar calcite with highly laminated structure. Few empty voids are found compared to Lf 4 . While the basal part of Lf 3 shows few impurities and more, well recognizable, fluid inclusions, the upper part shows more impurities and a higher number of hiatuses.

iii) Lithofacies Lf 2 , from 98 to 50 mm, less clearly laminated but comprises the highest number of impurities, minerals, bones fragments (microfaunal), and remains of organic material (e.g. amorph material, unidentified plant remains in the entire record. Oxides, rutiles and pyroclasts are the most common identified features. iv) Lithofacies Lf 1 , from 50 mm to the top of the core reveals two kind of microstructures: it is poorly laminated in its upper part with few impurities whereas its lower part shows a primary calcite formed in a subaqueous environment.

Chronology

Ten uranium-thorium (U/Th) ages were obtained from S6, two dates from S6bis cores and five from stalagmite S8 (Suppl., table 1). Two dates were considered as outliers. Minor age inversions with large uncertainties coincide petrographically with growth intervals rich in detrital material in the flowstone cores (Suppl., fig 3 ,table 1). High initial thorium concentrations are most likely due to organic material, or iron oxides that are common at depths 390-370 mm and 90-70 mm in core S6. The corresponding dates S6-19-10 and S6bis-01 are out of sequence and were therefore excluded from the age model (Suppl., table 1). The COPRA age-depth model indicates that core S6 grew from ca. 11.1 ± 1 to 1.5 ± 1.7 ka BP, including several short discontinuities (Fig. 2B). One noteworthy discontinuity at 80 mm depth in core S6 shows a change in growth (water flow) direction, followed by precipitation of impurities-rich calcite. This discontinuity covers the period from ∼5.8 to ∼2.7 ka BP. Considering that a thin water film is still running today over the wet flowstone, the age model was bound with the year of sampling in its youngest part. Core S6bis, sampled 10 cm from core S6, grew between 3.4 ± 2.7 ka and 2.7 ± 0.5 ka BP, with a charcoal encrusted in the calcite and dated at 4.11± 0.04 cal BP. Stalagmite S8 grew from 6.8 ± 0.1 to 1.29 ± 0.22 ka BP (Fig. 2B) and a hiatus is observed between 5.7 and 4.2 ka BP. A series of dark detrital layers filled with microfaunal bone fragments mark two major discontinuities, D1 at 18 mm and D2 at 22 mm depth. The latter separates segment 1, dated to between ∼4.2 and ∼1.3 ka BP, from segment 2, dated to between ∼6.7 ka and ∼5.7 ka BP.

Stable isotopic composition of calcite, modern water and fluid inclusions

Stalagmite core S6  18 O (-6.28 to -9.81 ‰) and  13 C (-2.14 to -16.26 ‰) values display distinct signatures (Fig. 3). Between ~12 and ~8.5 ka BP, the time series shows overall low  18 O values, with the lowest observed at ∼8.5 ka BP. A distinct positive excursion is noticeable between 10.5 and 10.1 ka BP. From 8.5 to 6 ka BP, we find a general increase in both  18 O and  13 C values and higher multi-decadal scale variability (Fig. 3). The highest isotope values (-6.3 ‰ for  18 O, -2 ‰ for  13 C) are found at ~6 ka BP. From 3.5 to 1.5 ka BP, a shift to lower carbon and oxygen isotope values in core S6 corresponds well with stable isotope profile from stalagmite S8 (Fig. 3). After 1.5 ka BP, the upper part of core S6 shows an increase in both the  18 O and  13 C values until the present day. The overall resolution of the isotope record is infra-to multidecadal, except for the topmost part (from ~3.2 to present), which is lower resolved. At a decadal scale, the  13 C profile co-varies with the  18 O record. High growth rate (Fig. 2) generally corresponds with lower  18 O and  13 C values. After ~8.5 ka BP, the growth rate decreases (Fig. 2B) drastically until ~5.8 ka BP, coeval with a slowly increasing trend in  18 O and  13 C.

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 7 Dripwater stable isotopes collected in the Cueva Chica show an average  18 O value of -11.24 ‰ and a D of -91.23 ‰. The isotope values cluster very narrowly and fall at the lower end of, and parallel to, the local meteoric water line (LMWL) (Fig. 4). The corresponding recent calcite deposits that form from the sampled dripwater show a  18 O value of -7.05 ‰ and  13 C of -15.2 ‰. Stable isotopes from fluid inclusion exhibit a wide (20 ‰) range of  18 O FI values, which is much larger than the  18 O range in the host calcite (3.5 ‰). The fluid inclusion deuterium isotope ratios (D FI ) data show a 30 ‰ range. In D - 18 O space the lowest observed isotope ratios are found close to the GMWL, while values progressively depart from the GMWL following a slope of ~1.4 (Fig. 4). (Rozanski et al., 1993). The age of each FI sample is indicated in the graph and the SE for each FI is better than 0.1 ‰ for δ 18 O and 0.3 ‰ for δ 2 H (1). The FI distribution shows the most contaminated/dirty samples on the right while clean (in terms of detrital content) samples to the left.

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 8

High resolution Sr/Ca data

The Sr/Ca record of core S6 has a temporal resolution of about 0.1 to 12 years (Fig. 3). The 1000*Sr/Ca ratio varies between 0.2 and 325 cps (avg = 2). The median record (shown in red) varies only little between 1.3 and 2.6 cps but reveals some maxima between prior to 11,5 ka, from ∼10,5 and 10 ka BP and from ∼1.0 to present-time ka. Minima occur from ∼10.8 to 11.5, ∼1.8 and ∼3 ka BP. From ∼12 to 11.4 ka BP, Sr/Ca values are higher (median ∼1.6) followed by a peak of lower values from ∼11.3 to 10.6 ka BP (median ∼1.3). A return to higher values is marked at 10.2 ka and from 9.6 to 9.2 ka BP, followed by a general trend of increased Sr/Ca values (median ∼1.6) from ∼8.5 to 5.8 ka BP (median from ∼1.5 to 1.9), which coincides with high stable isotope values. From 3.2 ka BP onwards, the Sr/Ca median values are low (from ∼1.4 to 1.5), except for a short excursion at 0.7 and 0.3 ka BP. More rapid changes in the Sr/Ca ratios (median), showing annual to multi-annual variations, are superimposed on this long-term trend (as shown by the moving average). The Sr/Ca and stable isotope time series vary simultaneously, with higher Sr/Ca values corresponding with more positive  18 O and  13 C values.

Clumped isotope values

The ∆ 47 values of the 8 analyzed samples range from 0.6172 to 0.6601 ‰ (Suppl., table 4). From the bottom to the top (older to younger part of the speleothems), the ∆ 47 values progressively decrease from 0.6528 to 0.6438 ‰ between 11.3 and 6.5 ka BP. The minimum ∆ 47 value is reached with sample C3 at 6.5 ka BP. At the top of the speleothem, both samples C2 and C1 record the highest ∆ 47 value, 0.6601 and 0.6565 ‰ respectively. The sample C0, taken at the top of the speleothem, includes the most recent calcite and records a ∆ 47 value of 0.6415 ‰.

Discussion

Age growth behaviour of the studied speleothems

Building a composite COPRA age-depth models for cores S6a and nearby S6bis required lithofacies comparison of each core under optical microscope for the same depth interval. Optical observation allowed to relate several stratigraphical levels along with an additional 14 C dating on charcoal in core S6bis (Suppl., fig. ,3) and consider all the ages of core S6 and S6-bis on the same depth profile. The age model for core S6-S6bis (Fig. 2) reveals a rather continuous deposition from ~11.9 to ~5.8 ka BP, with an average growth rate of 90 mm/ka (range 4-300 mm/ka). The basal part from ~12 to ~9 ka BP shows a high growth rate of 170

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 9 mm/ka at the beginning of calcite precipitation in the cave. From ~9 ka onwards, the growth rate decreases and remains at/or below 37 mm/ka until ~5.8 ka BP, showing an overall gradual decrease in water availability to build the flowstone. At ~5.8 ka BP, a stratigraphical discontinuity (D) is found, likely resulting from a change in flow direction of the source water. This core section either precipitated at very slow growth rates of 4 mm/ka or contains multiple (unresolved) hiatuses. Charcoal fragments encrusted between clean and muddy calcite layers within D, dates to 4.11± 0.04 cal. BP and could be the result of an enhanced incave water flow event after a vegetation fire (with soil surface erosion by overland flow). The speleothem record continues at 2.7 ± 0.5 ka BP and calcite formed continuously but slowly until the present time, resulting of less favourable conditions for intensive calcite precipitation. Stalagmite S8 grew from ~6.8 to 2 ka BP, with an average growth rate of 68 mm/ka. A period of apparently very slow growth between 5.8 and 4 ka BP is attributed to either significant drying or one or more hiatuses that remain unresolved with the current dating information. This period of limited growth in stalagmite S8 coincides with the timing of the stratigraphical hiatus in core S6. This and less negative δ 13 C and δ 18 O values at the time (Fig. 4) signify reduced infiltration and less favourable conditions for intensive calcite precipitation in the cave. Local pollen data confirms our interpretation of drier conditions at the time [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF].

Interpreting the geochemical proxy record from the Cueva Chica

Stable isotope data from speleothem have been intensively studied in moderate temprate regions [START_REF] Baldini | Detecting & quantifying palaeoseasonality in stalagmites using geochemical and modelling approaches[END_REF][START_REF] Mcdermott | Palaeo-climate reconstruction from stable isotope variations in speleothems: a review[END_REF][START_REF] Mangini | Reconstruction of temperature in the Central Alps during the past 2000 yr from a δ 18 O stalagmite record[END_REF][START_REF] Lachniet | Climatic and environmental controls on speleothem δ 18 O values[END_REF][START_REF] Fairchild | Speleothem science: from process to past environments[END_REF], but less in cold temperate areas such as Patagonia [START_REF] Schimpf | The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies[END_REF].

δ 13 C as proxy for vegetation and soil development

Stalagmite δ 13 C can serve as qualitative proxy for changes in vegetation composition and density, soil microbial activity, and, frequently, for changes in infiltration dynamics [START_REF] Lechleitner | The potential of speleothems from Western Europe as recorders of regional climate: a critical assessment of the SISAL database[END_REF][START_REF] Fohlmeister | Modelling carbon isotopes of carbonates in cave drip water[END_REF]. At the Cueva Chica, soil and vegetation activity are highest at the end of spring (Nov-Dec). Together with higher effective infiltration during the winter-spring period, this results in higher CO 2 concentrations with low δ 13 C signature in the soil. Passing through the epikarst, the δ 13 C signal is adjusted to higher values, depending on the residence time of the percolating water and length of water-rock interaction [START_REF] Lechleitner | The potential of speleothems from Western Europe as recorders of regional climate: a critical assessment of the SISAL database[END_REF]. In addition, CO 2 degassing can occur i) in the epikarst if air pockets exist in the dry season, leading to prior carbonate precipitation or ii), in a ventilated cave atmosphere [START_REF] Deininger | Isotope disequilibrium effects: The influence of evaporation and ventilation effects on the carbon and oxygen isotope composition of speleothems-A model approach[END_REF], in both cases contributing to a shift of δ 13 C towards higher values. The speleothems from the Cueva Chica thus record the combined signal of epikarst and in-cave CO 2 degassing, vegetation composition and density as well as soil microbial activity [START_REF] Mcdermott | Palaeo-climate reconstruction from stable isotope variations in speleothems: a review[END_REF]. The observed very low δ 13 C values in the Chica record, reaching values such as -16 ‰, corroborate the interpretation that multiple processes, including microbial and plant activity, influence the δ 13 C signal. In South Patagonia, the vegetation type is dominantly a C3 type in a broad-leaved forest cover, sometimes mixed with C4 type in open grassland [START_REF] Cerling | Climate change in continental isotopic records[END_REF]. Today the Cerro Benitez is covered with Juncaceae (rushes) and grasses mixed with sparse forest on thin soils, and several fires have been recorded throughout the Holocene [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF]. Thus, the δ 13 C signal of postglacial soils above the cave is expected to be much higher than that of a developed Nothofagus forest soil (δ 13 C: -26 ‰ in [START_REF] Peri | Carbon (δ 13 C) and nitrogen (δ 15 N) stable isotope composition in plant and soil in S outhern P atagonia's native forests[END_REF]. More open vegetation or thin soils with limited microbial activity and soil CO 2 production would lead to higher δ 13 C [START_REF] Scholz | A comparison of different methods for speleothem age modelling[END_REF][START_REF] Genty | Dead carbon in stalagmites: carbonate bedrock paleodissolution vs. ageing of soil organic matter. Implications for 13 C variations in speleothems[END_REF][START_REF] Genty | Precise dating of Dansgaard-Oeschger climate oscillations in western Europe from stalagmite data[END_REF].

Sr/Ca as proxy for infiltration dynamics

Speleothem Sr/Ca constitutes a sensitive proxy for infiltration changes in the epikarst, with higher values being recorded during times of reduced effective moisture availability [START_REF] Fairchild | Trace elements in speleothems as recorders of environmental change[END_REF]. Other mechanisms can explain Sr mobility within the epikarst and include changes in weathering rates, aerosol input, soil activity [START_REF] Verheyden | Mg, Sr and Sr isotope geochemistry of a Belgian Holocene speleothem: implications for paleoclimate reconstructions[END_REF][START_REF] Fairchild | Modification and preservation of environmental signals in speleothems[END_REF][START_REF] Baker | The Properties of Annually Laminated Stalagmites-A Global Synthesis[END_REF][START_REF] Sinclair | Magnesium and strontium systematics in tropical speleothems from the Western Pacific[END_REF] that can induce high-frequency variability on short timescales (decadal to annual). At the Cueva Chica, speleothem Sr/Ca reacts to local infiltration changes and climate saisonnality with i) high precipitation and effective infiltration in austral winter and, ii) low precipitation and high potential evapotranspiration during austral summer (Fig. 1B). Long-term drier climate with shorter wet seasons and low precipitation can lead to open conditions in soil and epikarst, and strong CO 2 degassing from infiltrating water and in the cave atmosphere. These processes can lead to PCP within the epikarst [START_REF] Verheyden | Mg, Sr and Sr isotope geochemistry of a Belgian Holocene speleothem: implications for paleoclimate reconstructions[END_REF]Fairchild et al., Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 10 2006), which in turn leads to higher Sr concentration in the aqueous solution and ultimately in the speleothem [START_REF] Verheyden | Mg, Sr and Sr isotope geochemistry of a Belgian Holocene speleothem: implications for paleoclimate reconstructions[END_REF][START_REF] Fairchild | Trace elements in speleothems as recorders of environmental change[END_REF].

Speleothem and dripwater δ 18 O

Calcite δ 18 O is generally interpreted as related to precipitation amount, atmospheric circulation pattern, seasonal changes in infiltration [START_REF] Mcdermott | Palaeo-climate reconstruction from stable isotope variations in speleothems: a review[END_REF]Dreybrodt and Scholtz, 2011). Additionally, local factors can affect δ 18 O in the epikarst and cave, including evaporation and CO 2 degassing, temperature, and mixing of older and younger water in the epikarst [START_REF] Mühlinghaus | Modelling fractionation of stable isotopes in stalagmites[END_REF]. Chica cave receives precipitation mainly from the Pacific Ocean through WSW winds. These waters are characterized by low δ 18 O in precipitation (δ 18 O p ) values (Suppl. S4) and fall on the GMWL, while water collected during spring and summer show high δ 18 O p. Effective infiltration and epikarst recharge are biased towards the winter season and possibly early summer. Dripwater collected in Chica and nearby Milodon caves in early summer show δ 18 O drip values biased towards autumn-winter δ 18 O p . Unfortunately, no dripwater is available from other seasons. Even though the sampling site is deep inside the cave (60 m from the entrance) with high relative humidity, we cannot strictly exclude the possibility that evaporation affected dripwater δ 18 O. Cave ventilation could lower relative humidity sufficiently to induce evaporation. The temperature effect on δ 18 O drip is unlikely a major factor because cave air temperature does not vary significantly (T cave air = 4.6 ± 0.6°C). Finally, mixing of infiltration waters of different age in the epikarst likely results in the observed relatively stable δ 18 O drip values through a year (Suppl. fig. 6,table 2). The small offset between the two S6 and S8 speleothems suggests some degree of mixing along the individual water pathways to the two sampling sites. The water residence time in the epikarst is likely on the order of months to years. The epikarst thickness above Chica cave (40 m) is similar to that observed at Ernesto (Italy), Han sur Lesse (Belgium) or Bunker (Germany) caves (epikarst thickness between 15 and 30 m, [START_REF] Van Rampelbergh | Monitoring of a fast-growing speleothem site from the Han-sur-Lesse cave, Belgium, indicates equilibrium deposition of the seasonal δ 18 O and δ 13 C signals in the calcite[END_REF][START_REF] Kluge | Dating cave drip water by tritium[END_REF][START_REF] Miorandi | Epikarst hydrology and implications for stalagmite capture of climate changes at Grotta di Ernesto (NE Italy): results from long-term monitoring[END_REF] where lags of several months to years between surface and cave are found. Given the observed narrow range of δ 18 O in dripwaters (Fig. 4) and infiltration pattern (Suppl., fig. 6) we suggest that both dripwater and speleothem δ 18 O values represent a buffered (multi-)annual mean signal, likely biased towards the winter season. The Chica δ 18 O cc record (Fig. 3A) thus integrates a complex signal of precipitation history and corresponding δ 18 O p . Earlier work on three speleothems combined with intensive cave microclimate monitoring in Marcello Arévalo (53°S), an open-air cave located further south, showed that δ 13 C and δ 18 O were both linked to effective infiltration [START_REF] Schimpf | The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies[END_REF]. There, the most suitable stalagmites preserving the link between stable isotope signal and effective infiltration in MA cave were the ones showing high and constant growth rates (>67 µm/a). In our case, the flowstone S6-S6bis in the Chica cave grew mostly continuously, with limited growth from 5 to 3 ka BP, and growth rates suggest that S6 was regularly submerged. A high growth rate of 132 µm/a is found prior to 9 ka that subsequently slowed to ca. 33 µm/a over the course of the Holocene until recent time. Stalagmite S8 grew relatively fast at a rate of 111 µm/a from 6 to 5 ka BP, and slowly at a rate of 11 µm/a after 4 ka BP. We suggest then that variations in the Chica δ 18 O signal reflect mainly changes in amount of precipitation and effective infiltration, and to some extent changing moisture transport trajectories throughout the Holocene.

General climatic conditions during the Holocene in southwest Patagonia

The combined stable isotope, growth rate, and Sr/Ca time series suggest three climatic regimes throughout the last 12 ka in Southern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5 ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene.

The early Holocene humid period (12-8.5 ka BP)

During the early Holocene period, the δ 18 O cc values are low until 8.5 ka BP, except for two excursions at 10.5 ka and 8.5 ka BP (Fig. 6). The δ 18 O values are the lowest of the entire Holocene record and vary between -7 and -9 ‰, suggesting relatively wet conditions. This notion is supported by a high growth rate of ca. 60-170 µm/year. The flowstone grew continuously under sufficiently humid conditions to maintain infiltration in the epikarst zone and limited PCP as indicated by low Sr/Ca and low but highly variable δ 13 C values (Fig. 3A). The study site was likely covered by broad-leaved mixed C3/C4 type vegetation on a developed soil Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 11 with higher CO 2 production through biogenic activity. The onset of this wet early Holocene period agrees closely with abundant N. dombeyi pollen in the Vega Benitez peat profile [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF], suggesting a developed woodland cover. A similarly developed Nothofagus forest was found in the Punta Burslem pollen records [START_REF] Mcculloch | Late glacial and Holocene climate variability, southernmost Patagonia[END_REF] further South. Other records from lake Tamar and peat GC2 also suggest a wet period with a peak in humidity around 11 ka BP (Fig. 5A) [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF]. Both, high abundance of hygrophytic taxa (a sensitive proxy for extremely humid environments) at peat GC2, and high terrestrial organic carbon concentrations linked to extreme rainfall events at lake Tamar [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF] are indicative of humid conditions. Fig. 6. The  18 O and  13 C records of Cueva Chica compared with global and regional records for the last 14 ka. A. (top to base) Comparison of continental records in Southern Chile, including the % Nothofagus dombeyi pollen from Mallin Pollux [START_REF] Markgraf | Vegetation and fire history during the last 18,000 cal yr BP in Southern Patagonia: Mallín Pollux, Coyhaique, Province Aisén[END_REF], terrestrial organic carbon in lake Tamar [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF], % hygrophytes from peat bog GC2 [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF], lago Cipreses warm cycles (Moreno et al., 2018), moraine building events in the Lago Argentino basin (Kaplan et al., 2016) & glacial fluctuations in the Marinelli fjord (Hall et al., 2019), Cueva Chica isotope record (this study), % of Nothofagus dombeyi pollen from Vega Benitez [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF] and % of Nothofagus dombeyi pollen vs total normal pollen from Punta Burslem (McCulloch et al., 2020). ACR timing is indicated by blue shade from Gest et al. (2017).

B. (top to base) Comparison of global and regional records in Southern Chile, including sea surface temperatures (SSTs) from

GeoB3313-1 [START_REF] Lamy | High-and low-latitude climate control on the position of the southern Peru-Chile Current during the Holocene[END_REF] and ODP1233 [START_REF] Lamy | Glacial reduction and millennial-scale variations in Drake Passage throughflow[END_REF], moraine building events from Lago Argentino (Kaplan et al., 2016), Cueva Chica  18 O, Marcello Arévalo (MA) speleothem  18 O [START_REF] Schimpf | The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies[END_REF], periods of open marine conditions in Prince Gustav Channel, Antarctic Peninsula & T anomalies from James Ross Island [START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate & ice-shelf history[END_REF],  18 O from West Dome C (WDPM, 2013) and 60°S december insolation [START_REF] Berger | Insolation values for the climate of the last 10 million years[END_REF]. Red rectangles indicate dry periods and blue rectangles wet periods defined by the Cueva Chica speleothem record. The early Holocene dry episode begins with a positive excursion of δ 18 O and δ 13 C centred at 10.5 ka BP, concurrent with high Sr/Ca values. Between 10.7 ka and 10.2 ka BP (Fig. 6A), the Cueva Chica isotopic profile records significant drying with a short-lived low rainfall period impacting the vegetation cover on the Cerro Benitez. At the Vega Benitez site upstream of the Chica cave watershed, N. dombeyi forest declined from 11.54-10.78 cal ka BP and was replaced by Poaceae and Cyperaceae taxa. This shift in pollen assemblages is typical of a continued transition from lake to a peat bog and the increase in Poaceae and Cyperaceae likely reflects the spread of grasses and sedges over the emerging bog surface [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF]. This reduction of water surface suggests less water availability and overall reduced local precipitation, which supports the dry event recorded in the Chica record. The different timing of the dry event in the Chica samples (10.7-10.2 ka BP) and in nearby lake Vega Benitez (11.5-10.7 ka BP) is likely Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 12 related to limited chronological control in both archives. It is worth mentioning that comparable drying events are found in other regional records between 11 and 10 ka BP, including a rapid decline in N. dombeyi in the Punta Burslem peat bog [START_REF] Mcculloch | Late glacial and Holocene climate variability, southernmost Patagonia[END_REF] and a clear reduction in the abundance of hygrophytes in the GC2 peat bog [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF]. After 10.2 ka BP, increased moisture availability is noticeable in the δ 18 O profile with the most negative values of the whole record centred at 8.5 ka BP (Fig. 6A). The δ 13 C values start to become more negative, but not below -12 ‰. This wet phase is less prominent than the early Holocene period, but still noticeable in the Vega Benitez pollen record, with short-lived peaks in N.dombeyi pollen at 10.7 and 8.2 ka BP [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF]. 5.3.2. The mid-Holocene drying trend (8.5-5.8 ka) After 8 ka BP, a slow trend towards higher δ 13 C values in the Chica record is mirrored in a persistent rise in the number of deteriorated pollen and a corresponding decrease of well preserved pollen in most of the remaining record of Vega Benitez [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF]. Overall, the changing δ 13 C trend and pollen assemblages as well as differential pollen preservation indicate reduced moisture availability. The trend in the δ 13 C profile and a corresponding two permil shift to higher δ 18 O shows the onset of a robust change in vegetation cover induced by reduced precipitation and less effective infiltration until 5.8 ka BP. The clear trend in the Chica record confirms regional drying as interpreted from reduced hygrophytic taxa in the GC2 peat bog and lower terrestrial organic carbon concentrations in lake Tamar. Further South, low abundance of N. dombeyi between 10 ka and 7 ka BP in Punta Burslem [START_REF] Mcculloch | Late glacial and Holocene climate variability, southernmost Patagonia[END_REF] also suggests drier conditions. The response of all the records indicates a consistent drying trend across 50°S to 55.5°S. This trend seems to be contrasted by the Mallin Pollux pollen profile further North [START_REF] Markgraf | Vegetation and fire history during the last 18,000 cal yr BP in Southern Patagonia: Mallín Pollux, Coyhaique, Province Aisén[END_REF], which might mark a contrasting N-S climatic gradient, although additional records would be required to confirm this interpretation.

Return to wet conditions during late Holocene (4-0.5 ka BP)

From 4 to 0.7 ka BP, decreasing δ 18 O and δ 13 C values in the Chica record reflect a return of more humid conditions. This coincides with a relatively humid phase in the Vega Benitez [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF] where four successive peaks in N.dombeyi abundance are observed at 3.3, 2.8, 2, and 0.7 ka BP (Fig. 6A). Low δ 18 O in Marcello Arévalo (MA) speleothem (53°S) indicates wet conditions from 2.5 to 0.7 ka BP. Higher N. dombeyi concentrations in Burslem peat record confirm this interpretation, but no clear humid phase is found in Lake Tamar during the late Holocene. After 0.7 ka BP, our stable isotope record increases again and suggests the return of drier local conditions. This agrees with reduced N.dombeyi abundance in the Vega Benitez record and a similar trend in the MA stable isotope records.

Global and regional drivers of climate variability in SW Patagonia

The flowstone in the Chica cave started to grow significantly from 12 ka onwards during a period of high Pacific SST [START_REF] Lamy | High-and low-latitude climate control on the position of the southern Peru-Chile Current during the Holocene[END_REF]2015), with > 4°C warming after the Antarctic Cold reversal (ACR) (Fig. 6B). A similar temperature shift is observed at the same time in the Antarctic James Ross Island ice core, and a trend towards higher δ 18 O is found in Antarctic ice from West Dome C (Weiss divide project members, 2013). Both observations mark the onset of deglaciation in Antarctica and a reduction in sea-ice cover. Despite minimum summer insolation at 11-12 ka BP in the Southern hemisphere [START_REF] Berger | Insolation values for the climate of the last 10 million years[END_REF], the early Holocene was the warmest period in Southernmost South America, consistent with ice core data and the rise in SST in the South Pacific. This warming in both polar ice and Southern Ocean surface coincides with enhancement of the southwesterly winds (SWW) in the centre of the wind belt [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF], but is difficult to explain by orbital forcing. The warming during the early Holocene might be attributable to changes in global ocean circulation which involves a bipolar seesaw-like surface temperature pattern [START_REF] Lamy | Holocene changes in the position and intensity of the southern westerly wind belt[END_REF] and a rise in air temperature in the southern hemisphere [START_REF] Ganopolski | The influence of vegetation-atmosphere-ocean interaction on climate during the mid-Holocene[END_REF][START_REF] Hodell | Abrupt cooling of Antarctic surface waters & sea ice expansion in the South Atlantic sector of the Southern Ocean at 5000 cal yr BP[END_REF]. A response of the SWW to changes in the strength of the Atlantic meridional overturning circulation (AMOC) has been previously proposed for Termination 1 [START_REF] Lamy | Modulation of the bipolar seesaw in the S-E Pacific during Termination 1[END_REF]. Model experiments [START_REF] Timmermann | Mechanisms for millennial-scale global synchronization during the last glacial period[END_REF] suggest a rapid signal transfer between the AMOC and SSW shifts with an increase of SWW strength south of 50°S and decreased wind strength in the mid-latitudes between 40° to 50°S. The response of terrestrial archives in Southern Patagonia to this atmosphere/ocean feedback is reflected in a reduction of glacier advances in Lago Argentino (50°S) and higher precipitation at Cerro Benitez (Cueva Chica) and the Chilean coast, likely in concert with higer temperatures. From 9 to 5 ka BP, a slight decrease in SE Pacific SST went hand in hand with a minor temperature decrease in on James Ross Island (64°S) (Fig. 6B). The most significant change in regional conditions was increased Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 13 ice-shelf instability along the Antarctic Peninsula [START_REF] Mulvaney | Recent Antarctic Peninsula warming relative to Holocene climate & ice-shelf history[END_REF], that began around 10 ka BP and expanded gradually after 9 ka BP. The intensification of ice-shelf instability along the Antarctic Peninsula is concordant with increasing summer insolation in the Southern hemisphere, which intensified a poleward shift of the SWWs in response to global warming [START_REF] Mcculloch | Late glacial and Holocene climate variability, southernmost Patagonia[END_REF]. Over the Patagonian landmass, this implied a reduction in moisture supply from the Pacific onto the Patagonian shore, lower total precipitation over the Chica cave and decreased glacier advances (warm/dry conditions) at Lago Argentina (50°S). After 5 ka BP, a different climatic background arises in Southern Patagonia, with SST and the James Ross Island ice core records indicating a gradual temperature decline (Fig. 6B). This pattern is consistent with an equatorward shift of the SWWs in response to a cooling Southern hemisphere, known as the Neoglacial period. Despite increasing insolation in the Southern hemisphere the Neoglacial cooling began at least ca. 5 ka BP [START_REF] Glasser | Late Pleistocene and Holocene palaeoclimate and glacier fluctuations in Patagonia[END_REF]. In turn, increased AMOC exported heat from the South Atlantic to the North Atlantic, triggering sea-ice growth around Antarctica and glacial advances in Southern Patagonia such as at Lago Argentino (Fig. 6B). One global feedback at the end of the mid-Holocene is the establishment of modern El Niño-Southern Oscillation (ENSO) frequencies [START_REF] Clement | Orbital controls on the El Nino/Southern Oscillation and the tropical climate[END_REF][START_REF] Moy | Variability of El Niño/Southern Oscillation activity at millennial timescales during the Holocene epoch[END_REF]. The SWW storm tracks extended to lower latitudes, inducing a return to wetter conditions along the Patagonian coast, as found in both Marcello Arévalo speleothem and Chica records after 4 ka BP. However, moisture patterns were highly variable due to increased insolation seasonality [START_REF] Markgraf | Paleoclimate reconstruction along the Pole-Equator-Pole transect of the Americas (PEP 1)[END_REF] and intensified ENSO [START_REF] Moreno | Millennial-scale climate variability in NW Patagonia over the last 15000 yr[END_REF]. This increased variability with rapid climate change (RCC) is recorded in several lake records [START_REF] Fletcher | Zonally symmetric changes in the strength and position of the Southern Westerlies drove atmospheric CO 2 variations over the past 14 ky[END_REF][START_REF] Moreno | Millennial-scale climate variability in NW Patagonia over the last 15000 yr[END_REF]2018b), but less clear in Cueva Chica speleothems, although the δ 18 O signal seems to be more variable. 5.5. Interpretation of fluid inclusion D and  18 O Speleothems fluid inclusions (FI) can retain the original isotopic composition on 'fossil' dripwater [START_REF] Affolter | New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)[END_REF][START_REF] Matthews | Eastern Mediterranean climate change deduced from the Soreq Cave fluid inclusion stable isotopes and carbonate clumped isotopes record of the last 160 ka[END_REF][START_REF] Van Breukelen | Fossil dripwater in stalagmites reveals Holocene temperature and rainfall variation in Amazonia[END_REF][START_REF] Wassenburg | Penultimate deglaciation Asian monsoon response to North Atlantic circulation collapse[END_REF]Warken et al. 2022). When fluid inclusions are well-preserved, FI isotope data (δ 18 O ; δD) fall onto or near the modern LMWL while a significantly lower regression slope of FI isotope results would indicate secondary evaporation [START_REF] Clark | Water-Rock Interaction[END_REF]. If the FI water indeed mirrors the original precipitation, the slope would reflect humidity during and after precipitation. Slope values decrease with humidity (e.g., a slope of 4.5 would indicate humidity levels of 50%). Fluid inclusion samples from the Chica S6 core reveal some intriguing complexity. While some samples fall near the LMWL, more than 50% of the samples diverge with a slope of 1.4 (Fig. 4). This line resembles a secondary evaporation line, which could result from cave ventilation [START_REF] Nehme | Speleothem record from Pentadactylos cave (Cyprus): new insights into climatic variations during MIS 6 and MIS 5 in the Eastern Mediterranean[END_REF]Warken et al. 2022), but the slope of the line is unusually low for such evaporation scenario [START_REF] Clark | Water-Rock Interaction[END_REF], which suggests that other processes must be at work, like diagenetic alteration of fluid inclusion water [START_REF] Uemura | Experimental evaluation of oxygen isotopic exchange between inclusion water and host calcite in speleothems[END_REF], or an analytical artefact leading to incomplete water extraction from the fluid inclusions. (Suppl. S5 table 3,comments). The line of reasoning described here reduces essentially the most trustworthy FI data to samples with the lowest isotope values in Fig. 4 and closest to LMWL. The trustworthy FI isotope dataset can be therefore reduced to a single projected dripwater value (δ 18 O : -11.8‰ ; δD : -87‰) for the time interval (8.5 to 11.3 ka BP) covered in the data. Since almost all fluid inclusion samples represent a short time interval in the earliest Holocene, the projected isotope values should be representative of the beginning of the Holocene. Considering the uncertainties in our projections, we believe values given from FI-3, FI-5 and FI-8b samples (Suppl., table 3) are not significantly different from the modern-day dripwater values (Fig. 4).

Temperature estimates based on FI and D47

Clumped isotope temperatures (T 47 ) offer the prospect to reconstruct the temperature at which the speleothem formed, independent of the isotopic composition of the dripwater. Previous work (Daeron et al. 2019;[START_REF] Fiebig | Calibration of the dual clumped isotope thermometer for carbonates[END_REF] suggests that cave carbonates precipitated near isotopic equilibrium conditions retain their original T 47 signal. Unfortunately, kinetic isotope fractionation, induced by rapid CO 2degassing or evaporation of dripwater can overprint the original clumped isotope signal and render derived temperatures unrealistic. This kinetic effect on speleothem is well known and has been studied previously [START_REF] Affek | Kinetic isotope effect in CO 2 degassing: Insight from clumped and oxygen isotopes in laboratory precipitation experiments[END_REF][START_REF] Kluge | Reconstruction of drip-water δ 18 O based on calcite oxygen and clumped isotopes of speleothems from Bunker Cave (Germany)[END_REF]Guo andZhou, 2019, Matthews et al., 2021). Kinetic effects caused can be evaluated by comparing FI stable isotopes and dripwater isotope data (Fig. 4). Samples close to the LMWL can be regarded as trustworthy, whereas samples located well below the modern LMWL are likely to be affected by secondary evaporation. This means that FI-based temperature estimates from samples with δ 18 O values <-8 permil (Fig. 4) might reflect environmental temperatures, while temperature estimates from samples with higher δ 18 O values should be discarded.

Electronic copy available at: https://ssrn.com/abstract=4172978 draft -Patagonia paper 14 Our samples display T 47 values between 4.8±1.3°C and 17.4±1.6°C, higher than modern cave air temperature (5±1°C) (Fig. 7). Four samples (C1, C2, C5b, C6) overlap within error with modern cave air temperature, but the remaining four (C0, C3, C4, C5) are significantly higher than expected (Fig. 7). Sample C1 is taken from inside a soda straw that was embedded in the floor after breakage. It is likely that the soda straw remained filled with water as long as it was actively dripping, therefore constantly replenishing the DIC pool. At the same time, CO 2 -degassing was likely limited by the barrier of the soda straw walls and a thick water column inside [START_REF] Smith | Calcite straw stalactites growing from concrete structures[END_REF]. These conditions support the recording of unaltered clumped isotope signals and we trust the observed T 47 value. Sedimentological evidence suggests that sample C2 precipitated as cave pool carbonate under subaqueous conditions that limit rapid CO 2 -degassing. Under such conditions the clumped isotope signature is likely to remain unaltered by kinetic fractionation [START_REF] Kele | Temperature dependence of oxygen-and clumped isotope fractionation in carbonates: a study of travertines and tufas in the 6-95°C temperature range[END_REF][START_REF] Breitenbach | Coupled Mg/Ca and clumped isotope analyses of foraminifera provide consistent water temperatures[END_REF][START_REF] Drysdale | Magnesium in subaqueous speleothems as a potential palaeotemperature proxy[END_REF]). These two samples suggest that, starting from at least 2.5 ka, mean temperatures in the Cerro Benitez were close to modern (Fig. 7). Fig. 7. The T-Kinetics distribution of the measured clumped isotopes (x axis) and the modern cave air are reported within 2s error. The values indicated in green are samples with less kinetics and close to the modern cave air, the ones in red are samples with high kinetics and shifted towards higher temperatures. For comparison, are the Chica cave'  18 O signal and the pollen % from the Vega Benitez peat [START_REF] Mcculloch | The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation[END_REF] as indicator of dryness/wetness trend in the Cerro Benitez. For regional comparison, the reconstructed paleoprecipitation from pollen record of the Cerro Frias peat [START_REF] Tonello | Quantitative reconstruction of Holocene precipitation changes in southern Patagonia[END_REF] to the North and from pollen record of Potrok Aike Lake in the Argentinian pampa (Shabitz et al., 2013) to the East. Similarly, samples C5b and C6 from the early Holocene were likely deposited from a thicker water film under wetter conditions and their clumped isotope temperatures are likely valid. While their T 47 values overlap with the modern temperature, the large error margins do not allow us to establish whether the early Holocene was significantly warmer than today or not. If minimal kinetic fractionation is expected, T 47 (max 10°C) might well align with globally higher-than-modern temperatures (6±3°C) between 10.8 and 10.3 ka. The samples C0, C4 and C5 show temperatures only slightly higher than today and might be realistic, although we cannot exclude any impact of kinetic fractionation and thus 'to high" reconstructed temperatures. The remaining sample C3 is unrealistically high and kinetic fractionation due to CO 2degassing and/or evaporation is sucpected to affect this sample. A trend towards less negative δ 18 O values shortly after that sample is noticeable, which might be interpreted as local drying that lead to an increased kinetic fractionation. To summarize, local temperatures might have been slighly higher in the early Holocene (11-8 ka BP) compared to today (Fig. 7), although the large error margins do not allow a quantitative estimation of such warming. Local temperatures were similar to today since at least 2.6 ka BP. A dry interval around 8.5 -5.5 ka likely affected the cave's hydrology such that kinetic fractionation altered the clumped isotope system, resulting in too warm apparent reconstructed temperature. The comparison of local reconstructed T(°C) from Chica cave with other semi-quantitative (Pollen) signals from Vega Benitez marsh and reconstructucted paleo-precipitation from Cerro Frias (Fig. 7), show a regional similarity in the drying trend during time interval 8.5 -5.5 ka and a return to wet conditions from 3.5 to 1 ka. However, the climatic paleo-precipitation trend shown from Potrok Aiketo the East seems to be out of phase with the Andean records.

Conclusions

The Cueva Chica record from the Cerro Benitez (51°S) in one of the rare studied carbonate record located far South in the Southern Andes. This study provides a first highly-resolved isotopic, elemental and paleotemperature record spanning the Holocene from the last 12 ka, albeit with a hiatus from 5.8 to 4 ka BP. The stable isotope and trace elements curves from speleothems show a covariability in the signals. First, cave monitoring and comparision with regional climatic data suggest that both dripwater and speleothem δ 18 O values represent a buffered (multi-)annual mean signal, likely biased towards the winter season. Overall, the oxygen isotope signal reflects changes in amount of precipitation and effective infiltration in the studied site, and to some extent changing moisture transport trajectories throughout the Holocene. Second, δ 13 C signal reflects a combined signal of epikarst and in-cave CO 2 degassing, vegetation composition and density as well as soil activity. Third, the Sr/Ca elemental data shows a moderate sensitiveness to infiltration changes in the epikarst and behave in concert with the δ 13 C signal, albeit with different intensitiy to dryness between both proxies. The multi-proxy analysis of the petrography, growth rate, stable isotopes and elemental data in the Chica record suggest three main climatic phases throughout the last 12 ka in Southern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5 ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene. The climate variability from the Chica record is in phase with other regional peat and lake records located between 50° ant 55°S along the Andes mountain corridor and Western Pacific side, but is out of phase with records located North to 50° latitude. These tri-phased climate regimes recorded in the Chica cave are the result of global drivers controlling the strength and shifts of the SWWs throughout the Holocene. The early Holcene was the warmest period in Southernmost South America, and might be attributable to changes in global ocean circulation which involves a rise in air temperature and a strength in SWW from 50°S. The response over landmass in Southern Patagonia is higher precipitation over the Chica cave and the Chilean coast, likely in concert with higer temperatures. After 9 ka BP, an intensification of ice-shelf instability along the Antarctic Peninsula is concordant with increasing summer insolation in the Southern hemisphere, which intensified a poleward shift of the SWWs in response to global warming. This significant change in regional conditions implied a reduction in moisture supply from the Pacific onto the Patagonian shore and lower total precipitation over the Chica cave. After 5 ka BP, a different climatic background arises, with a gradual SST decline, consistent with an equatorward shift of the SWWs in response to a cooling Southern hemisphere, known as the Neoglacial period. The SWW storm tracks extended to lower latitudes, inducing a return to wetter conditions with highly variable moisture patterns along the Patagonian coast, as found in the Cueva Chica and other terrestrial records after 4 ka BP. The reconstructed paleotemperatures based on fluid inclusisons and (T 47 ) from the Cueva Chica speleothems provide a reasonable estimation of past terrestrial temperature in the Cerro Benitez throughout the Holocene: local temperatures might have been slighly higher in the early Holocene (11-8 ka BP BP) compared to today. A dry interval around 8.5 -5.5 ka BP likely affected the cave's hydrology such that kinetic fractionation altered the clumped isotope system, resulting in too warm apparent reconstructed temperature. Since at least 2.6 ka BP, local temperatures were similar to today. 7. Acknowledgments. We thank the Corporación Nacional Forestal Chile (CONAF) authorities and the rangers of the Park "Monumento Natural Cueva del Milodón" for their permission to sample in the Cueva Chica. Jorge Canales Helmer and Mario Margoni are thanked for the permission they gave to work in their properties. Both Proyecto Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT ; PI: F.Martin) funding project n°1180272 and the Centre National pour la Recherche Scientifique (CNRS) funding project PICS-GEOCEBE ; PI: D.Todisco): Geoarchaeology of caves from Cerro Benitez, Última Esperanza, Chilean Patagonia (2017-2019) supported field investigations, sample shipment and laboratory analysis.

CRediT author statement

Electronic copy available at: https://ssrn.com/abstract=4172978

Fig. 2 .

 2 Fig. 2. Lithofacies, stable isotope and age models for the studied samples. A. Stable isotope depth profile along the S6 core together with U/Th and 14 C dates and lithofacies. Explanation of lithofacies and red rectangles locating the thin sections are displayed in the supplementary (Suppl. S2). B. Age-depth model of core S6 and S6bis. C. Age-depth model for stalagmite S8.Age-depth models are based on COPRA[START_REF] Breitenbach | Constructing proxy records from age models (COPRA)[END_REF].3.3. Calcite and water stable isotopes measurements

Fig. 3 .

 3 Fig. 3. Multiproxy ( 18 O,  13 C and Sr/Ca ratios) records from samples S6 and S8. A. The original isotope. B. Ratio of µXRF Sr and Ca instenisties (cps) presented as median values (red smoothed line) to highlight the broader trends and variations from 12 ka BP to present. The moving average (black lines) is shown for both stable isotope and Sr/Ca profiles. No Sr/Ca data is available for the periods from 5.5 to 3.2 ka BP, and 2.5 to 2 ka BP.

Fig. 5 .

 5 Fig. 5. Stable oxygen and carbon isotope variability over time, showing their dispersion and interrelationship for different time intervals. Three phases are identified : i) low δ 13 C (avg: ~ -15 ‰) and δ 18 O values (avg. ~ -9 ‰) during the early-Holocene wet period (with exception of two excursions at 10.5 ka and 8.5 ka), ii) high δ 13 C (avg. ~ -8 ‰) and δ 18 O values (avg. ~ -7 ‰) during the mid-Holocene dry period, iii) general wet conditions in the late Holocene with low δ 13 C (avg. ~ -12 ‰) and δ 18 O values (avg. ~ -8 ‰).5 Discussion5.1 Age growth behaviour of the studied speleothemsBuilding a composite COPRA age-depth models for cores S6a and nearby S6bis required lithofacies comparison of each core under optical microscope for the same depth interval. Optical observation allowed to relate several stratigraphical levels along with an additional 14 C dating on charcoal in core S6bis (Suppl., fig., 3) and consider all the ages of core S6 and S6-bis on the same depth profile. The age model for core S6-S6bis (Fig.2) reveals a rather continuous deposition from ~11.9 to ~5.8 ka BP, with an average growth rate of 90 mm/ka (range 4-300 mm/ka). The basal part from ~12 to ~9 ka BP shows a high growth rate of 170