Dennis Sánchez-Mora
email: dsanchezmora@mun.ca

John Jamieson

Mathilde Cannat

Javier Escartín

Thibaut Barreyre

Dennis Sánchez

Effects of substrate composition and subsurface fluid pathways on the geochemistry of seafloor hydrothermal deposits at the Lucky Strike Vent Field, Mid-Atlantic Ridge

 Spatial variations in in situ sulfur isotope compositions at Lucky Strike indicate differences in fluid/rock interactions in the sub-surface.

 In situ sulfur isotope data suggests that >80% of the available H2S in the ascending hydrothermal fluid has precipitated in the subseafloor.

 The Ba/Co ratio of hydrothermal deposits discriminates those associated with E-MORBs from other mafic/ultramafic hosted deposits.

Introduction

Subseafloor magmatism drives hydrothermal circulation and the formation of metal and sulfurrich mineral deposits at or below the seafloor [START_REF] Hannington | Volcanogenic Massive Sulfide Deposits[END_REF][START_REF] Lydon | Ore deposit models 14. Volcanogenic massive sulphide deposits. Part 2: genetic models[END_REF][START_REF] Tivey | Generation of Seafloor Hydrothermal Vent Fluids and Associated Mineral Deposits[END_REF]. The geochemistry of seafloor hydrothermal deposits is controlled by several factors, including the composition of the subseafloor lithosphere with which the circulating fluids react, temperature, pressure, the presence and type of sediment, and magmatic volatile input into the system [START_REF] Doe | Zinc, Copper, and Lead in Midocean Ridge Basalts and the Source-Rock Control on Zn/Pb in Ocean-Ridge Hydrothermal Deposits[END_REF][START_REF] Hannington | Physical and chemical processes of seafloor mineralization at mid-ocean ridges[END_REF][START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF]. At Lucky Strike, a vent field located south of the Azores on the Mid-Atlantic Ridge (MAR), the deposits are composed largely of a suite of hydrothermal minerals (pyrite, chalcopyrite, sphalerite, marcasite, anhydrite, and amorphous silica) that are typical for basalt-hosted seafloor hydrothermal deposits [START_REF] Fouquet | Tectonic Setting and Mineralogical and Geochemical Zonation in the Snake Pit Sulfide Deposit (Mid-Atlantic Ridge at 23°N)[END_REF][START_REF] Kase | Copper-rich sulfide deposit 23°N, Mid-Atlantic Ridge: Chemical composition, mineral chemistry, and sulfur isotopes[END_REF][START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF][START_REF] Petersen | Third dimension of a presently forming VMS deposit: TAG hydrothermal mound, Mid-Atlantic Ridge, 26[END_REF]. However, the deposits at Lucky Strike also contain abundant barite, which [START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF] link to an enriched mid-ocean basalt (E-MORB) substrate associated with the nearby Azores hotspot.

The mineralogy and distribution of major and trace metals within the Lucky Strike hydrothermal deposits are not uniform, suggesting vent field scale variations in vent fluid composition [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF][START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. Both spatial and temporal variations in fluid chlorinity and CO2 concentrations have been documented, indicating subseafloor fluid phase separation and effects of magma replenishment, respectively [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF][START_REF] Damm | The geochemical controls on vent fluids from the Lucky Strike vent field , Mid-Atlantic Ridge[END_REF][START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF][START_REF] Pester | Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount[END_REF]. Results from previous sulfur isotope analyses from the main field at Lucky Strike indicate typical δ 34 S values for mid-ocean ridge hosted hydrothermal systems of between ~0 and 10‰ [START_REF] Rouxel | Subsurface processes at the lucky strike hydrothermal field, Mid-Atlantic ridge: Evidence from sulfur, selenium, and iron isotopes[END_REF]. In this study, we present new mineralogical, bulk geochemical, and in situ sulfur isotope data from hydrothermal samples (n=23) collected during the 2011-2015 MoMARsat maintenance cruises of the EMSO-Azores observatory (European Multidisciplinary Seafloor and water-column Observatory) from several of the hydrothermal edifices at Lucky Strike [START_REF] Blandin | MOMARSAT2013 cruise, RV Pourquoi pas ?[END_REF][START_REF] Cannat | MOMARSAT2011 cruise, RV Pourquoi pas ?[END_REF][START_REF] Cannat | MOMARSAT2012 cruise, RV Thalassa[END_REF][START_REF] Sarradin | MOMARSAT2014 cruise, RV Pourquoi pas ?[END_REF], 2015). We document the spatial variations in composition (mineralogical, geochemical, and in S isotopes) of the hydrothermal deposits to 1) evaluate the mineralogical controls on minor and trace element partitioning within the deposits; and 2) link these variations to the geological controls on hydrothermal venting conditions at the vent field scale.

In this study we also further investigate the influence of the Azores hotspot on the composition of hydrothermal deposits along the MAR. We develop geochemical criteria based on major and trace element compositions of hydrothermal deposits from MAR-hosted vent fields to fingerprint specific host rock compositions, which can vary from E-MORB to ultramafic rock.

Insights into the local and regional geological controls on the compositions of seafloor hydrothermal deposits is becoming increasingly important due to the growing interest in the economic potential of these deposits. Large seafloor hydrothermal deposits with high concentrations of base and precious metals (e.g., Cu, Zn, Au, and Ag) are potential targets for future mining [START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Petersen | News from the seabed -Geological characteristics and resource potential of deep-sea mineral resources[END_REF][START_REF] Rona | Resources of the sea floor[END_REF]. However, environmentally deleterious metals such as As, Cd, Se, Sb, which occur as trace metals within the sulfide minerals can also accumulate [START_REF] Fallon | Geological, mineralogical and textural impacts on the distribution of environmentally toxic trace elements in seafloor massive sulfide occurrences[END_REF][START_REF] Hannington | Volcanogenic gold in the massive sulfide environment[END_REF]Layton-Matthews et al., 2008;[START_REF] Martin | Trace element systematics and ore-forming processes in mafic VMS deposits: Evidence from the Troodos ophiolite, Cyprus[END_REF]. Results from this study will contribute to the understanding of the controls of substrate composition on the metal endowment, and therefore provide a framework for predictive assessment of the economic potential and associated environmental risks of exploiting seafloor massive sulfide deposits (SMS) based on geological setting on mid-ocean ridges.

Geological setting

The Lucky Strike segment is located along the slow-spreading Mid-Atlantic Ridge, approximately 360 km southwest of the Azores archipelago, near the triple junction between the North American, African, and Eurasian plates (Figure 1) [START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF][START_REF] Escartín | Crustal thickness of Vshaped ridges south of the Azores: Interaction of the Mid-Atlantic Ridge (36°-39°N) and the Azores hot spot[END_REF]. This segment is currently spreading at a full rate of ~20-25 mm/yr [START_REF] Argus | Geologically current motion of 56 plates relative to the no-net-rotation reference frame[END_REF][START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF], and is bound to the north by a non-transform offset with the Menez Gwen segment and to the south by a non-transform offset with the North Famous segment (Figure 1). The Lucky Strike segment formed as a product of rifting of an oceanic plateau associated with the Azores hotspot that began at ~10 Ma [START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF][START_REF] Escartín | Crustal thickness of Vshaped ridges south of the Azores: Interaction of the Mid-Atlantic Ridge (36°-39°N) and the Azores hot spot[END_REF][START_REF] Gente | Interaction between the Mid-Atlantic Ridge and the Azores hot spot during the last 85 Myr: Emplacement and rifting of the hot spotderived plateaus[END_REF]. The melt anomaly associated with the Azores hotspot is propagating southward, along the ridge, forming a V-shaped ridge that indicates shallowing of the ridges and its flanks towards the Azores hotspot, which is interpreted based on gravity and bathymetric data as a temporal and spatial variations in melt supply to the ridge axis that result from ridge-hotspot interactions [START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF][START_REF] Escartín | Crustal thickness of Vshaped ridges south of the Azores: Interaction of the Mid-Atlantic Ridge (36°-39°N) and the Azores hot spot[END_REF]. [START_REF] Gente | Interaction between the Mid-Atlantic Ridge and the Azores hot spot during the last 85 Myr: Emplacement and rifting of the hot spotderived plateaus[END_REF].

The Lucky Strike segment is ~70 km long, with a prominent axial volcano, named the Lucky Strike Seamount, that rises to 1500 mbsl in the central part of the segment from bathymetric lows of ~3500 mbsl towards the northern end of the segment and ~3200 mbsl towards the southern end of the segment, and is bounded by an overall ~20 km wide fault-bounded rift valley (Figure 2). Bathymetry and sidescan sonar imagery record cyclic volcanic (magmatic) crustal construction followed by tectonic (rifting) phases [START_REF] Escartín | Lucky Strike seamount: Implications for the emplacement and rifting of segment-centered volcanoes at slow spreading mid-ocean ridges[END_REF]. Recent volcanic episodes produced two volcanic centers that are aligned along the ridge axis and separated by a flat depression that is interpreted to be a recent but now fossil lava lake (Figure 3a) [START_REF] Humphris | Geotectonic setting of hydrothermal activity on the summit of Lucky Strike Seamount (37°17'N, Mid-Atlantic Ridge)[END_REF][START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF]. Both volcanic structures are now cut by a series of ridge-parallel normal faults, with the older, northern, volcanic edifice experiencing a higher degree of rifting than the younger, southern, volcanic edifice (Figure 3a) [START_REF] Escartín | Lucky Strike seamount: Implications for the emplacement and rifting of segment-centered volcanoes at slow spreading mid-ocean ridges[END_REF][START_REF] Humphris | Geotectonic setting of hydrothermal activity on the summit of Lucky Strike Seamount (37°17'N, Mid-Atlantic Ridge)[END_REF]. The Lucky Strike rift valley floor is paved by volcanic rocks that range in composition from transitional mid-ocean ridge basalt (T-MORB) to E-MORB [START_REF] Gale | Enriched basalts at segment centers: The Lucky Strike (37°17'N) and Menez Gwen (37°50'N) segments of the Mid-Atlantic Ridge[END_REF]. Basalts with a more E-MORB affinity are found towards the center of the segment, whereas the T-MORB compositions are distributed along the rest of the segment. The stratigraphy of the lava flows indicate that E-MORB lavas are crosscut by T-MORB lavas [START_REF] Gale | Enriched basalts at segment centers: The Lucky Strike (37°17'N) and Menez Gwen (37°50'N) segments of the Mid-Atlantic Ridge[END_REF][START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF]. Lava morphologies vary from sheeted flows to pillow lavas, with sheeted flows dominant in the neovolcanic zone that hosts the hydrothermal fields [START_REF] Escartín | Lucky Strike seamount: Implications for the emplacement and rifting of segment-centered volcanoes at slow spreading mid-ocean ridges[END_REF][START_REF] Gini | Extrusive upper crust formation at slow-spreading ridges: Fault steering of lava flows[END_REF].

Focused hydrothermal activity is restricted to the central region of the Lucky Strike Seamount (Figure 3). Seismic reflection studies have identified an axial magma chamber that lies ~3.5 km below the seafloor, and normal faults that propagate below the axial volcano [START_REF] Combier | Three-dimensional geometry of axial magma chamber roof and faults at Lucky Strike volcano on the Mid-Atlantic Ridge[END_REF][START_REF] Singh | Discovery of a magma chamber and faults beneath a Mid-Atlantic Ridge hydrothermal field[END_REF]. Microseismicity data suggest that hydrothermal circulation occurs primarily along-axis, and extends into the crust to within a few hundred meters of the axial magma chamber reflector in the narrow faulted area at the volcano summit [START_REF] Crawford | Hydrothermal seismicity beneath the summit of Lucky Strike volcano, Mid-Atlantic Ridge[END_REF]. The location of the vent field is also associated with a crustal magnetic low caused by hydrothermal alteration of the underlying rocks [START_REF] Miranda | Identification of the magnetization low of the Lucky strike hydrothermal vent using surface magnetic data[END_REF].

At the vent field scale venting and hydrothermal deposits are associated with normal faults and occur for the most part near a fossil lava lake at the volcano summit (Figure 3) [START_REF] Barreyre | Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF][START_REF] Fouquet | A detailed study of the Lucky Strike hydrothermal site and discovery of a new hydrothermal site: Menez Gwen[END_REF][START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF]. Focused venting also occurs 1.4 km to the east of the central ridge axis, at a site called Capelinhos [START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. The spatial association of hydrothermal venting with faulting suggest that faulting is the primary control on fluid discharge [START_REF] Barreyre | Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. Diffuse venting has been documented at Ewan, located 1.5 km south of the main field (Figure 3) [START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. The maximum temperature measured is 340°C at the main Lucky Strike field (South Crystal) and 324°C at Capelinhos [START_REF] Barreyre | Temporal variability and tidal modulation of hydrothermal exit-fluid temperatures at the Lucky Strike deep-sea vent field, Mid-Atlantic Ridge[END_REF][START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. The hydrothermal deposits at Lucky Strike were identified in previous studies via dredging, followed by autonomous underwater vehicle (AUV) and remotely operated vehicle (ROV) bathymetric mapping coupled with photomosaic imaging [START_REF] Barreyre | Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF][START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF][START_REF] Langmuir | Distribution , Mineralogy , and Geochemistry of Selenium in Felsic Volcanic-Hosted Massive Sulfide Deposits of the Finlayson Lake District , Yukon Territory , Canada[END_REF][START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF]. Observations from time series imaging of the seafloor, acquired in 1996, 2006, 2008, and 2009, suggest that the heat flux associated with hydrothermal venting is decreasing, likely as a result of cooling of the axial magma chamber that is driving the fluid circulation in this system (Thibaut [START_REF] Barreyre | Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics[END_REF]. Radioisotope ( 226 Ra) dating of hydrothermal barite indicates that hydrothermal venting at this site has been ongoing for at least 6,600 years and has accumulated at an average rate of ~194 t/yr (Sánchez-Mora et al., submitted).

Rock samples for this study were collected using the Victor 6000 ROV during the MoMARsat cruises from 2011 to 2015 on the R/V Pourquoi pas ? and R/V Thalassa in 2012. Sampling mainly focused on hydrothermal deposits on several sites within the main vent field as well as on Capelinhos (Table 1). Samples for the main field at Lucky Strike (n=19) and Capelinhos (n=4) 3a). White solid lines show approximate extent of the Lucky Strike Seamount. The white dashed lines are the axial valley walls. NTO are non-transform offsets. Bathymetry from the Sudaçores cruise [START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF][START_REF] Escartín | Crustal thickness of Vshaped ridges south of the Azores: Interaction of the Mid-Atlantic Ridge (36°-39°N) and the Azores hot spot[END_REF]. [START_REF] Barreyre | Temporal variability and tidal modulation of hydrothermal exit-fluid temperatures at the Lucky Strike deep-sea vent field, Mid-Atlantic Ridge[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. The dashed red lines show the volcanic rifted structures v2 (higher degree of rifting) to the north and v1 in the south. White dashed outline is a fossil lava lake. B) Venting of 222°C fluid (Tmax); [START_REF] Damm | The geochemical controls on vent fluids from the Lucky Strike vent field , Mid-Atlantic Ridge[END_REF] at a sulfide chimney at the Sintra vent complex within the main Lucky Strike hydrothermal field. The length of the robotic arm is ~75 cm. C) Chimneys and high-temperature venting at the Capelinhos site [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. The temperature probe is ~1 m long. Bathymetry sources: [START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF] and [START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF].

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems 7

Methodology

Bulk geochemistry

For bulk multi-element geochemistry, 23 samples were crushed at Memorial University using a ring pulverizer with a tungsten carbide grinding container and then analyzed at Activation Laboratories LTD (Actlabs). Samples were analyzed using: 1) instrumental neutron activation analysis (INAA) for Au, Ag, As, Ba, Co, Fe, Na, Sb, Se, and Zn; and 2) Na2O2 fusion and inductively coupled plasma optical emission spectroscopy (ICP-OES) and mass spectrometry (ICP-MS) for Ca, Mo, Ni, Sr, Al, Cd, Cu, Ga, Ge, In, Mg, Mn, Pb, S, Si, Sn, Tl, and V [START_REF] Hoffman | Instrumental neutron activation in geoanalysis[END_REF]. Accuracy and precision for INAA values are both better than ±5%, based on repeat (n=7) analysis of the GXR-1 standard. For the Na2O2 fusion ICP method, accuracy is better than ±7%, based on repeat (n=3) measurement of the OREAS 922 standard, with the exceptions of Ni and Sr, for which accuracy is 17%. Precision for the ICP method is better than 10%, except for Ni and Pb, which have precisions of 20% and 12%, respectively.

In situ sulfur isotope measurements

In situ sulfur isotope measurements were performed using a Cameca IMS 4f Secondary Ion Mass Spectrometer at the MAF-IIC Microanalysis Facility at Memorial University. Sulfidebearing samples (n=16) were embedded in epoxy in a 25.4 mm diameter aluminum ring and prepared as polished mounts, and sputter coated with 300 Å of Au to mitigate charging under primary ion bombardment. Isotopic analyses (n=52) were performed by bombarding the sample with a 0.8-1.0 nA primary ion microbeam accelerated through a 10 keV potential and focused into a 15-20 µm diameter spot. Each spot was pre-sputtered for 120 s using a 10 μm raster to exclude exotic material in the polished surface from the analysis. Negatively charged sputtered secondary ions were accelerated into the mass spectrometer through a 4.5 keV potential. Signals for 32 S -, 34 S - and a background position at 31.67 Da were obtained by cyclical magnetic peak switching. Standard counting time and peak sequence used were 0.5 s at the background position, 2.0 s on 32 S -, and 6.0 s on 34 S -. A typical analysis consisted of accumulating 80 peak cycles. All peak signals were collected with an ETP 133H multiple-dynode electron multiplier (em) and processed through ECL-based pulse-counting electronics with an overall dead time of 11 ns. The production and detection of sputtered secondary ions produces an instrumental mass fractionation (IMF) bias between the actual 34 S/ 32 S of the sample and that measured by the mass spectrometer. The magnitude of the IMF varies substantially between sulfide minerals. For this reason, the 34 S/ 32 S measured in samples of pyrite were corrected for IMF by comparison to replicate measurements of in-house reference materials UL9B (pyrite;  34 S: +16.3‰) and a Norilsk chalcopyrite ( 34 S: +8.4‰). Measured 34 S/ 32 S ratios are transformed to the Vienna Cañon Diablo Troilite (V-CDT) scale using 34 S/ 32 SVCDT = 0.0441626 [START_REF] Ding | Calibrated sulfur isotope abundance ratios of three IAEA sulfur isotope reference materials and V-CDT with a reassessment of the atomic weight of sulfur[END_REF]. Data are presented in standard delta notation:

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

8 𝛿 34 𝑆 = ቆ (𝑅) 𝑠𝑎𝑚𝑝𝑙𝑒 (𝑅) 𝑉-𝐶𝐷𝑇 -1ቇ × 1000
Where R = 34 S/ 32 S. Analyses yield internal precisions on individual  34 S determinations of better than ±0.3‰ (1) and the overall reproducibility, based on replicate standards analyses, is typically better than ±0.45‰ (1).

Results

Mineralogy and geochemistry

4.1.1.Mineralogy

Rock samples from Lucky Strike were collected primarily from the hydrothermally active Sintra, Tour Eiffel, Chimiste, Isabel, White Castle and Bairro Alto edifices (Figure 3a; [START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF]. Within the samples, mineral distributions change from the exterior to the interior of the chimneys, as typically described at black smoker deposits [START_REF] Fouquet | Geodiversity of hydrothermal processes along the Mid-Atlantic ridge and ultramafic-hosted mineralization: A new type of oceanic Cu-Zn-Co-Au volcanogenic massive sulfide deposit[END_REF][START_REF] Hannington | Physical and chemical processes of seafloor mineralization at mid-ocean ridges[END_REF][START_REF] Haymon | Growth history of hydrothermal black smoker chimneys[END_REF], with a lower temperature mineral assemblage of barite, anhydrite, marcasite, and pyrite with millimeter-scale goethite rims dominating the exterior of the chimney, and a higher-temperature mineral assemblage of sphalerite and chalcopyrite dominating the interior and lining fluid conduits (Figure 4a-e). Early marcasite forms plumose, colloform, or ringlike textures. Later stage marcasite is massive and euhedral. Subhedral to euhedral pyrite overgrows marcasite and co-precipitates with sphalerite that exhibits a range of textures, from plumose to subhedral and massive (Fig. 4d, f, g). Late stage chalcopyrite has massive and euhedral textures, and is often replacing or overgrowing sphalerite (Fig. 4d, h, i). Supergene alteration consists of exterior goethite rinds and atacamite (Figure 4f), and secondary covellite and bornite replacing chalcopyrite (Figure 4g). No major mineralogical differences are identified between Sintra, Tour Eiffel, and White Castle, except for an absence of pyrite in samples collected from Sintra, and absence of covellite in samples from White Castle.

Samples from Capelinhos show similar mineralogical assemblages and textural characteristics to the main Lucky Strike field, with lower temperature assemblages in the outer chimney walls that transition to higher temperature assemblages towards the interior. However, the primary difference is the occurrence of a second generation of sphalerite (Sph2), chalcopyrite (Cpy2), and barite (Ba2), that overprint previous generations (Figure 4g, h, i) suggesting temporal fluctuations in temperature of mineralizing fluids [START_REF] Eldridge | Mineral textures and their bearing on formation of the Kuroko orebodies[END_REF]. Supergene alteration includes replacement of chalcopyrite by covellite and minor bornite, goethite and atacamite.

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems 10 generation of acicular barite infilling voids. Sample from the inner part of a chimney from Tour Eiffel (MOM14-579-ROC1). I) Sphalerite and chalcopyrite overgrown by a second generation of sphalerite and chalcopyrite and marcasite from the Capelinhos site (MOM14-PL583-ROC4). Images D, G, H, and I are plane-polarized reflected light photomicrographs. Image F was taken under cross-polarized reflected light.

4.1.2.Bulk geochemistry of hydrothermal deposits Principal component analysis (PCA) was performed to identify statistical trends in the chimney sample dataset. The analysis was performed using the 28 elements of which at least 50% of the samples contained concentrations greater than their respective detection limits. When reported concentrations were below detection limits, a value representing 65% of the detection limit was used [START_REF] Palarea-Albaladejo | Compositional methods for estimating elemental concentrations below the limit of detection in practice using R[END_REF]. A sensitivity analysis using different thresholds for percentages of samples below detection limit and different values to represent the analyses below detection limit resulted in negligible changes to the results of the PCA analysis. A centred-logratio transformation was applied to the raw data to avoid closure problems and spurious correlations [START_REF] Pawlowsky-Glahn | Compositional data and their analysis : an introduction[END_REF]. The centred-log-ratio transformation (clr(x)) was calculated using the following equation:

clr(x) = [ln(x1/(x1•x2…xD)) 1/D ) , ln(x2/( x1•x2…xD)) 1/D ),…, ln(xD/( x1•x2…xD) 1/D )]
where D = the number of samples.

The PCA (Figure 5) reveals a cluster of elements associated with high-temperature sulfide minerals (e.g., Co, Cu, Se and Sn) with a negative PC1 loading, and a second cluster of elements associated with lower-temperature sulfide minerals (Ga, Sb, Zn, Cd, Mn, Si) with a positive PC1 loading.

Principal component 2 has positive loadings for sulfide mineral associated elements (transition and post-transition metals), and negative loadings for sulfate and oxide minerals associated elements (alkaline earth metals such as Ba, Sr, Ca, and Mg) but also Ni. Principal component 1 accounts for 37% of the variability in the dataset and PC2 accounts for 17% of the variability.

Accepted Article

This article is protected by copyright. All rights reserved. Table 1. Chemical composition of hydrothermal samples from Lucky Strike vent field (see supporting information Table S1 for full dataset that includes additional elements that were largely below detection limit). 6 and7). The δ 34 S values for marcasite and pyrite (n=30) average 1.0‰ (1σ = 1.8) and vary from -2.5 to 5.2‰. Values for chalcopyrite (n=22) average 4.4‰ (1σ = 2.1) and range from 1.0 to 8.7‰. Notable low (negative) δ 34 S values of -2.5 and -2.4‰ where obtained on marcasite from the Y3 and Isabel sites, respectively, which are part of the main field. Average marcasite and chalcopyrite sulfur isotope compositions from the main field (0.3‰, n=24, and 3.3‰, n=15, respectively) are lower than those for Capelinhos (3.7‰, n=6, and 6.8‰, n=7, respectively; Figure 7). Marcasite δ 34 S values do not vary significantly as a function of texture at the main field (Figure 6). At both sites, chalcopyrite is, on average, isotopically heavier by ~3‰ than marcasite (Figure 7). There is no apparent correlation between δ 34 S values and age for the seventeen samples for which both S isotope and age data are available (Sánchez-Mora et al., submitted).

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems 20

Discussion

The bulk, minor and trace element geochemical data presented in this study expands on the data originally presented by [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF] by including a more extensive suite of elements such as Au, Ag, As, Ba, Mo, Sb, Se, Sb, Si, and Sn (see Table 1). Additionally, this study includes data from samples from other areas of the vent field not included in the study by [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF], including the Capelinhos site, for which no data has been published to date. Results from the principal component analysis reflect the strong temperature control and influence of seawater on the mineral associations and trace element distributions within the deposits (Figure 5). An analysis of the distribution of the different sites within the Lucky Strike vent field that occur at different water depth within the field (Table 1) over the PC1 and PC2 space contrast with the interpretation of [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF], who suggested that, due to phase separation occurring at the seafloor or in the shallow subseafloor, the highest temperature fluids occur at the deepest vents within the vent field. This phase separation was hypothesized to be a main control on the variability of composition of the hydrothermal deposits [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF]. However, our data indicates no systematic variation in bulk geochemistry with water depth or deposit age (~6,600 years to present; Sánchez-Mora et al., submitted). Therefore, differences in mineral assemblages and geochemistry likely only reflects the stage (low-or high-temperature) at which the sample was formed and not necessarily linked to phase separation.

Controls on minor and trace element distributions at Lucky Strike

Minor and trace elements occur within the main mineral phases (chalcopyrite, marcasite, pyrite and sphalerite) in hydrothermal sulfide deposits and can be incorporated into their crystal structure or can occur as micro-or nano-scale inclusions [START_REF] Cook | Trace element analysis of minerals in magmatic-hydrothermal ores by laser ablation inductively-coupled plasma mass spectrometry: Approaches and opportunities[END_REF][START_REF] Fontboté | Sulfide minerals in hydrothermal deposits[END_REF][START_REF] Monecke | The Minor Element Endowment of Modern Sea-Floor Massive Sulfi des and Comparison with Deposits Hosted in Ancient Volcanic Successions[END_REF]. Minor and trace element distribution is generally evaluated via microanalytical techniques such as an electron microprobe and/or laser ablation ICP-MS (e.g., [START_REF] Berkenbosch | Trace element mapping of copper-and zinc-rich black smoker chimneys from brothers volcano, kermadec arc, using synchrotron radiation XFM and LA-ICP-MS[END_REF][START_REF] Grant | Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic Ridge, based on LA-ICP-MS analyses of pyrite[END_REF][START_REF] Keith | Trace element systematics of pyrite from submarine hydrothermal vents[END_REF][START_REF] Melekestseva | Gold-And silver-rich massive sulfides from the semenov-2 hydrothermal field, 13°31.13'N, Mid-Atlantic ridge: A case of magmatic contribution[END_REF]. Our approach uses PCA on bulk geochemistry of hydrothermal samples from the Lucky Strike vent field to determine the minor and trace element variability, which we compared to previous geochemical work conducted at Lucky Strike by [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF] and compared to other similar studies on mid-ocean ridges.

The mineralogy of the Lucky Strike hydrothermal deposits are typical for basalt hosted mid-ocean ridge deposits, which is generally dominated by marcasite, pyrite, sphalerite, and chalcopyrite with the notable exception of the high abundance of barite, which has been linked to high Ba concentrations in the underlying E-MORB substrate [START_REF] Langmuir | Distribution , Mineralogy , and Geochemistry of Selenium in Felsic Volcanic-Hosted Massive Sulfide Deposits of the Finlayson Lake District , Yukon Territory , Canada[END_REF]. High-temperature interiors of chimneys are dominated by chalcopyrite and euhedral pyrite and marcasite. Concentrations of In, Se, Co and Sn correlate with the major mineral-forming elements (Cu, Fe, and S) that comprise this high-temperature mineral assemblage (Figure 5). These associations have been documented in other seafloor hydrothermal sites (e.g., [START_REF] Auclair | Distribution of selenium in high-temperature hydrothermal sulfide deposits at 13° North, East Pacific Rise[END_REF][START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF]. Cobalt has been previously documented to be concentrated in marcasite and pyrite at Lucky Strike [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF]. The correlation between Co with Cu and Fe that are associated with the precipitation of minerals at high-temperatures suggests that Co is hosted in euhedral pyrite and marcasite that precipitated associated with these high-temperature mineral assemblages

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems 21 (Figure 5). At the basalt-hosted TAG hydrothermal field further south on the MAR, In is hosted primarily as a trace metal within chalcopyrite and marcasite, Sn is largely hosted within chalcopyrite, and Se is largely hosted in chalcopyrite and pyrite to a lesser extent [START_REF] Grant | Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic Ridge, based on LA-ICP-MS analyses of pyrite[END_REF]. Similarly, [START_REF] Lein | Sulfide Minerals in the Menez Gwen Nonmetallic Hydrothermal Field (Mid Atlantic Ridge)[END_REF] and [START_REF] Bogdanov | Mineralogical -Geochemical Features of Sulfide Ores from the Broken Spur Hydrothermal Vent Field[END_REF] report high concentrations of In within high-temperature mineral assemblages at Menez Gwen and Broken Spur, respectively, both also located at the MAR to the North and South of Lucky Strike, respectively. Selenium has also been documented to occur primarily within chalcopyrite at Lucky Strike [START_REF] Rouxel | Subsurface processes at the lucky strike hydrothermal field, Mid-Atlantic ridge: Evidence from sulfur, selenium, and iron isotopes[END_REF] but also in pyrite in a range of other seafloor hydrothermal deposits (e.g., Monecke et al., 2016, and references therein).

The lower temperature exteriors of chimneys from Lucky Strike are dominated by sphalerite (ZnS), barite (BaSO4), plumose marcasite and amorphous silica. Silver, Au, As, Ga, Cd, Sb, Tl, Pb, and Ge abundances correlate with the major mineral-forming elements (Zn, Ba, and Si) of this lower temperature mineral suite. The association of some of these trace elements (As, Sb, Cd, Mn, and Ag) with lower temperature minerals in the PCA (Figure 5) such as marcasite and sphalerite has been documented at Lucky Strike [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF] as well as at other hydrothermal deposits hosted on the MAR, including Menez Gwen [START_REF] Lein | Sulfide Minerals in the Menez Gwen Nonmetallic Hydrothermal Field (Mid Atlantic Ridge)[END_REF], TAG [START_REF] Grant | Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic Ridge, based on LA-ICP-MS analyses of pyrite[END_REF], Broken Spur [START_REF] Bogdanov | Mineralogical -Geochemical Features of Sulfide Ores from the Broken Spur Hydrothermal Vent Field[END_REF].

The elements Ca, Ba, and Sr, which are associated with the sulfate minerals anhydrite and barite, have a distinct negative loading with respect to PC2. Barium and Sr have minor positive loadings and Ca has a minor negative loading with respect to PC1 (Figure 5). The minor negative loading of Ca with respect to PC1 is consistent with anhydrite occurring primarily in association with the high-temperature sulfide mineral suite due to its absence at lower temperatures due to its retrograde solubility at temperatures below 150°C [START_REF] Blount | The solubility of anhydrite (CaSO4) in NaCl-H2O from 100 to 450°C and 1 to 1000 bars[END_REF]. In contrast, Ba and Sr have a positive loading with respect to PC1, consistent with the typical association of barite with lowertemperature sulfide minerals [START_REF] Jamieson | Precipitation and growth of barite within hydrothermal vent deposits from the Endeavour Segment, Juan de Fuca Ridge[END_REF]. The proximity of Sr to Ba in Figure 5 is likely the result of barite being significantly more abundant than anhydrite at Lucky Strike, as indicated by the higher Ba concentrations (and higher barite contents) in the samples compared to Ca.

Magnesium, V, Ni, and to a lesser extent, Mo and Na have a negative loading with respect to PC1 (Figure 5). At TAG, redox-sensitive elements such as V, Ni, and Mo are associated with the precipitation of pyrite and marcasite that has interacted with cold, Na-and Mg-rich seawater towards the exteriors of vents [START_REF] Grant | Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic Ridge, based on LA-ICP-MS analyses of pyrite[END_REF]. Alternatively, Ni, and V can also be associated with the formation and scavenging of Fe-oxyhydroxides [START_REF] German | Hydrothermal Processes[END_REF]. Regardless, the negative loading with respect to PC2 discriminates elements associated with sulfate and oxide minerals that precipitate upon direct interactions with seawater, which is consistent with the three samples with the lowest PC2 loadings that are barite and Fe-oxyhydroxides rich.

Differences in S isotope compositions between the main Lucky Strike field and Capelinhos

Overall, the sulfur isotope compositions of the sulfide deposits at Lucky Strike range between -2.5 and 8.7‰ (Figure 7), which is within the range of average δ 34 S values for sulfide minerals at other sediment-free and basalt-hosted mid-ocean ridge hydrothermal deposits [START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF][START_REF] Zeng | Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems: Implications for ore genesis and fluid circulation[END_REF]. The range in δ 34 S values for the main field reported in this study are similar to those reported by [START_REF] Rouxel | Subsurface processes at the lucky strike hydrothermal field, Mid-Atlantic ridge: Evidence from sulfur, selenium, and iron isotopes[END_REF]. The mineralogy of the Capelinhos site is similar to the mineralogy of the deposits at the main field, which is consistent with evidence from vent fluid trace element concentrations that correlate with chlorinity and indicate a common hydrothermal fluid source for these sites [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. However, the S isotope compositions of sulfide minerals from Capelinhos are ~3.5‰ higher than the average values at the main field (Figure 7). The range at Capelinhos is comparable to other sediment-free fast to slow spreading mid-ocean ridges sites such as TAG, East Pacific Rise South, and Axial Seamount [START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF][START_REF] Zeng | Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems: Implications for ore genesis and fluid circulation[END_REF].

At mid-ocean ridge-hosted hydrothermal sites, δ 34 S values of between ~0 and 10‰ are usually interpreted to be a result of two component mixing between igneous-derived sulfur (δ 34 S ≈ 0‰) leached from mid-ocean ridge crust and seawater sulfate (δ 34 S = 21‰); [START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF][START_REF] Shanks | Stable Isotopes in Seafloor Hydrothermal Systems: Vent fluid, hydrothermal deposits, hydrothermal alteration, and microbial processes[END_REF][START_REF] Zeng | Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems: Implications for ore genesis and fluid circulation[END_REF]. It is possible that the more positive δ 34 S values for sulfide minerals at Capelinhos are due to a higher relative contribution of reduced sulfur derived from seawater sulfate or a longer fluid flow pathway feeding the Capelinhos vents, or a combination of both [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. Also, in sediment free environments, the addition of isotopically-light H2S associated with disproportionation of magmatic SO2 can also drive the overall system towards lower δ 34 S values [START_REF] Gamo | Acidic and sulfate-rich hydrothermal fluids from the Manus back-arc basin , Papua New Guinea[END_REF][START_REF] Mcdermott | Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes[END_REF][START_REF] Shanks | Stable Isotopes in Seafloor Hydrothermal Systems: Vent fluid, hydrothermal deposits, hydrothermal alteration, and microbial processes[END_REF]. Fluctuations in vent fluid CO2 content [START_REF] Pester | Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount[END_REF] and recent magmatic intrusions detected from seismicity at Lucky Strike [START_REF] Dziak | Evidence of a recent magma dike intrusion at the slow spreading Lucky Strike segment, Mid-Atlantic Ridge[END_REF] indicate that magmatic volatiles may contribute to the hydrothermal system. A higher proportion of such volatiles could result in the relatively lower δ 34 S values in the hydrothermal precipitates in the main field. However, CO2 fluid data is not available for Capelinhos to assess differences in volatile input between this site and the main field. In addition, there is no mineralogical evidence of direct magmatic volatile input, such as the presence of high-sulfidation alteration assemblages, sulfosalts, and elevated concentrations of volatile associated trace elements such as Bi, Se, and Te [START_REF] Martin | Trace element systematics and ore-forming processes in mafic VMS deposits: Evidence from the Troodos ophiolite, Cyprus[END_REF][START_REF] De Ronde | Submarine hydrothermal activity and gold-rich mineralization at Brothers Volcano, Kermadec Arc, New Zealand[END_REF]. [START_REF] Rouxel | Subsurface processes at the lucky strike hydrothermal field, Mid-Atlantic ridge: Evidence from sulfur, selenium, and iron isotopes[END_REF] speculate that, at Lucky Strike, there is also a component of a fractionated sulfur source associated with microbial activity below the fossil lava lake. These interpretations highlight the ambiguity inherent in the interpretation of δ 34 S values on their own and the requirement of additional information to assess processes driving different sulfur isotope compositions at Lucky Strike.

Vent fluids at the main field are also depleted in Fe, enriched in Cl, and contain higher 87 Sr/ 86 Sr, relative to Capelinhos fluids [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF] interpret the higher 87 Sr/ 86 Sr at the main field to indicate higher rock/water ratios, even though the field lies directly above the heat source and the overall flow pathway is likely shorter. Longer residence times for fluids venting at the main field may result from locally reduced permeability. The fossil lava lake may act as a hydrological cap for ascending fluids, promoting lower overall permeabilities in the subsurface [START_REF] Arnulf | Constraints on the shallow velocity structure of the Lucky Strike Volcano, Mid-Atlantic Ridge, from downward continued multichannel streamer data[END_REF] leading to increased interaction with altered basalts, thus driving the δ 34 S values of the fluids and deposits closer to zero (Figure 8). [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF] report a ~65% depletion in the dissolved Fe concentration of the fluids from the main field, relative to Capelinhos. Concentrations of other dissolved species (e.g., Mg, Mn, Na, and SO4) and vent fluid pH indicate that this depletion is not a result of seawater dilution. Therefore it is suggested that significant amounts of precipitation of Fe-bearing minerals occur in the subseafloor below the main field [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. The precipitation of pyrite/marcasite would result in a temperature-dependent S isotope fractionation between the precipitated pyrite/marcasite and reduced S in the fluid. The fraction of reduced S removed from the fluid due to subseafloor pyrite/marcasite precipitation can be modelled over a range of temperatures as an open system Rayleigh distillation: 𝑅 = 𝑅₀ƒ (𝛼-1) where R is the isotopic ratio of the fraction f of reduced sulfur remaining in the fluid after pyrite/marcasite precipitation, R0 is the initial sulfur isotope ratio of the fluid, and α is the fractionation factor (α = RPy/RH2S). Compared to the vent fluids at the main field, the composition of the endmember venting fluids at Capelinhos have been interpreted to be more representative of the fluids within the deeper part of the hydrothermal reaction zone, based on the linear correlation of trace elements and chlorinity in the hydrothermal fluids at Lucky Strike [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF][START_REF] Pester | Subseafloor phase equilibria in high-temperature hydrothermal fluids of the Lucky Strike Seamount[END_REF]. The δ 34 S values from sulfide minerals at Capelinhos can therefore be used to represent R0 (i.e., the isotopic composition of the ascending fluids below the main field) and the δ 34 S values from the main field represent R. The temperature dependent fractionation factors (α), determine the different mass fractions (ƒ) at which the ~3.5‰ difference between Capelinhos and main Lucky Strike can be obtained. If fractionation factors are used between H2S and pyrite [START_REF] Ohmoto | Isotope of sulfur and carbon[END_REF]) from 150 and 350°C , fractions of 0.21 to 0.034 are obtained, respectively [START_REF] Hannington | Volcanogenic Massive Sulfide Deposits[END_REF].

Results from sulfur isotope modelling suggest that at least ~80% of the original H2S in the hydrothermal fluid at the main field precipitated below the seafloor, dominantly as pyrite/marcasite (Figure 8). A similar proportion (75%) of major and trace element deposition below the seafloor has been estimated at the seawater-dominated Reykjanes geothermal system in Iceland, which is considered an analogue to seafloor systems [START_REF] Grant | Trace metal distributions in sulfide scales of the seawater-dominated Reykjanes geothermal system: Constraints on sub-seafloor hydrothermal mineralizing processes and metal fluxes[END_REF]. The average value of H2S in hydrothermal fluids at the main field vents is 2.7 mmol/kg [START_REF] Charlou | Compared geochemical signatures and the evolution of Menez Gwen (35°50N) and Lucky Strike (37°17N) hydrothermal fluids, south of the Azores Triple Junction on the Mid-Atlantic Ridge[END_REF]. If this value represents less than 20% of the original H2S concentration, the original fluid H2S concentration would have been greater than ~14 mmol/kg. The amount of reduced S trapped in the subsurface as pyrite/marcasite is reasonably consistent with the amount of Fe estimated to have been trapped in the subsurface based on differences in vent fluid chemistry between the main field and Capelinhos [START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF].

Chalcopyrite is another Fe-bearing mineral that could have precipitated and trapped both Fe and S in the subsurface and commonly forms in the upflow zones of seafloor hydrothermal systems [START_REF] Franklin | Volcanogenic Massive Sulfide Deposits[END_REF]Galley et al., 2007). However, the fractionation factors between chalcopyrite and H2S at subseafloor hydrothermal conditions are extremely low (e.g., <0.3 (1000lnα) at 150°C, [START_REF] Ohmoto | Isotope of sulfur and carbon[END_REF] and very large amounts of reduced sulfur would have to precipitate in the subsurface to generate the predicted fractionations, requiring initial fluid H2S concentrations of >300,000 mmol. For comparison, maximum reported H2S concentrations for vent fluids are on the order of 110 mmol (Von [START_REF] Damm | Evolution of East Pacific Rise hydrothermal vent fluids following a volcanic eruption[END_REF]. Therefore, although chalcopyrite may be precipitating in the subseafloor, the isotopic differences between Capelinhos and the main field suggest that pyrite is the primary sulfide phase being precipitated. This interpretation is consistent with evidence from subsea drilling at TAG and from VMS deposits that show that upflow zones can be enriched in chalcopyrite but are dominated by pyrite (Galley et al., 2007;[START_REF] Knott | Petrology of hydrothermal mineralization: a vertical section through the TAG mound[END_REF].

It should be noted that the calculations and results presented above are predicated assuming isotopic equilibrium between the vent fluid and minerals. In seafloor hydrothermal systems, isotopic equilibrium can be evaluated comparing known temperatures of formation to temperatures calculated between mineral pairs-based equilibrium sulfur isotope fractionation. For example,

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems 24 there is a uniform difference in isotopic composition of ~3‰ between neighboring chalcopyrite and marcasite crystals at both the main field and Capelinhos (Figures 6). This difference is independent of sample location, and depositional age as there is no significant variation in δ 34 S values and mineral textures (e.g., plumose vs. euhedral marcasite) (Sánchez-Mora et al. submitted). The isotopic enrichment in 34 S in chalcopyrite, relative to marcasite, is consistent with equilibrium fractionation processes. Under equilibrium conditions, a 3‰ fractionation between chalcopyrite and marcasite corresponds to a crystallization temperature of 114°C (using fractionation factors by [START_REF] Kajiwara | Sulfur Isotope Partitioning in Metallic Sulfide Systems[END_REF]). This temperature is likely too low for typical crystallization temperatures for chalcopyrite (>250˚C) although marcasite can form at temperatures of up to 240˚C under hydrothermal conditions [START_REF] Hannington | Physical and chemical processes of seafloor mineralization at mid-ocean ridges[END_REF][START_REF] Murowchick | Marcasite precipitation from hydrothermal solutions[END_REF], suggesting that these mineral phases were not in isotopic equilibrium at the time of formation. This is consistent with textural evidence that indicates that these mineral phases did not co-precipitate (Figure 6), and the difference in isotopic composition between the two mineral phases is likely a result of either equilibrium or non-equilibrium isotopic partitioning between each mineral phase and the hydrothermal fluid at different temperatures of mineral formation and/or other possible kinetic isotopic effects, such as effects of microbial processes during marcasite formation [START_REF] Juniper | Biological influences on mineral deposition at deep-sea hydrothermal vents[END_REF]. Overall, an important outcome from this analysis is that subsurface sulfide mineral precipitation can change the S isotopic composition of the vent fluid and surficial deposits (Figure 8), yielding surficial isotopic compositions that are indistinguishable from isotopic compositions that result from simple two-component mixing between mantle sulfur and reduced seawater sulfate [START_REF] Ohmoto | Kinetics of reactions between aqueous sulfates and sulfides in hydrothermal systems[END_REF][START_REF] Ono | S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides[END_REF].

Geological controls on the composition of Lucky Strike and other vent fields along the Mid-Atlantic Ridge

The most distinctive compositional characteristic of both Lucky Strike and Menez Gwen (a vent field located ~90 km northeast from Lucky Strike, closer to the Azores hotspot) is the abundance of barite [START_REF] Bogdanov | Chemical Composition of the Hydrothermal Deposits of the Menez Gwen Vent Field (Mid-Atlantic Ridge)[END_REF][START_REF] Lein | Sulfide Minerals in the Menez Gwen Nonmetallic Hydrothermal Field (Mid Atlantic Ridge)[END_REF]. Compared to other basalt or ultramafic-hosted vent fields along the MAR that are not hotspot influenced, such as TAG, Snake Pit, and Rainbow, Lucky Strike contains significantly more barite, and higher concentrations of Ba, Sr and Mo, but lower Au and Sn (Figure 9); [START_REF] Bogdanov | Mineralogical-Geochemical Peculiarities of Hydrothermal Sulfide Ores and Fluids in the Rainbow Field Associated with Serpentinites, Mid-Atlantic Ridge (36°14[END_REF][START_REF] Fouquet | Tectonic Setting and Mineralogical and Geochemical Zonation in the Snake Pit Sulfide Deposit (Mid-Atlantic Ridge at 23°N)[END_REF][START_REF] Grant | Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic Ridge, based on LA-ICP-MS analyses of pyrite[END_REF];

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems 26 [START_REF] Honnorez | Mineralogy and chemistry of sulfide deposits drilled from hydrothermal mound of the Snake Pit active field[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF]. The basaltic substrate at Lucky Strike and Menez Gwen is dominated by E-MORB [START_REF] Gale | Enriched basalts at segment centers: The Lucky Strike (37°17'N) and Menez Gwen (37°50'N) segments of the Mid-Atlantic Ridge[END_REF][START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF], which is enriched in incompatible elements (e.g., Ba and Sr) compared to the normal mid-ocean ridge basalts (N-MORB) that host TAG and Snake Pit [START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF]. The E-MORB substrate composition and associated enrichment in incompatible elements (Ba and Sr) is linked to the melting of the metasomatized mantle associated with the Azores hotspot [START_REF] Langmuir | Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37°N on the Mid-Atlantic Ridge[END_REF].

Figure 9. Average bulk geochemistry of hydrothermal samples of selected Mid-Atlantic Ridge hosted hydrothermal sites, normalized to average mid-ocean ridge basalt composition [START_REF] Arevalo | Chemical variations and regional diversity observed in MORB[END_REF]. The diamond symbol indicates sites hosted in detachment fault systems. Lucky Strike data is from this study and [START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF], Menez Gwen [START_REF] Bogdanov | Chemical Composition of the Hydrothermal Deposits of the Menez Gwen Vent Field (Mid-Atlantic Ridge)[END_REF], TAG [START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Hannington | The formation of atacamite during weathering of sulfides on the modern seafloor[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Lisitsyn | Hydrothermal formations of the ocean rift zone[END_REF][START_REF] Rona | Active and relict sea-floor hydrothermal mineralization at the TAG hydrothermal field, mid-Atlantic ridge[END_REF][START_REF] Thompson | Active vents and massive sulfides at 26°N (TAG) and 23°N (Snakepit) on the Mid-Atlantic Ridge[END_REF], Snake Pit [START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Honnorez | Mineralogy and chemistry of sulfide deposits drilled from hydrothermal mound of the Snake Pit active field[END_REF][START_REF] Kase | Copper-rich sulfide deposit 23°N, Mid-Atlantic Ridge: Chemical composition, mineral chemistry, and sulfur isotopes[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Fouquet | Tectonic Setting and Mineralogical and Geochemical Zonation in the Snake Pit Sulfide Deposit (Mid-Atlantic Ridge at 23°N)[END_REF], and Rainbow [START_REF] Bogdanov | Mineralogical-Geochemical Peculiarities of Hydrothermal Sulfide Ores and Fluids in the Rainbow Field Associated with Serpentinites, Mid-Atlantic Ridge (36°14[END_REF][START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF]. Menez Gwen (n=12), Lucky Strike (n=50), Rainbow (n=6), TAG (n=190), and Snake Pit (n=105). Full dataset provided in supporting information Table S2.

In contrast to E-MORB hosted Lucky Strike and Menez Gwen, the active TAG mound, which contains relatively low concentrations of Ba and Sr, is hosted within N-MORB in an active detachment fault zone [START_REF] Humphris | The Trans-Atlantic Geotraverse hydrothermal field: A hydrothermal system on an active detachment fault[END_REF]. Rainbow is hosted in ultramafic rocks but is influenced by basaltic rocks in the vicinity of the hydrothermal site. Rainbow has a relatively high Ni and Co content, which is typical for ultramafic-hosted sites [START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF][START_REF] Mozgova | Mineralogy of massive sulfides from the Ashadze hydrothermal field 13°N, Mid-Atlantic Ridge[END_REF]. At ultramafic sites, serpentinization causes the release of Co and Ni during the alteration of primary silicate minerals such as olivine [START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF]. Barium enrichment in E-MORB hosted hydrothermal sites and Co enrichment in ultramafic hosted hydrothermal sites have been widely documented (e.g., [START_REF] Hannington | Sea-Floor Tectonics and Submarine Hydrothermal Systems[END_REF]. The Ba/Co ratio within hydrothermal deposits

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems 27 can therefore be used to discriminate E-MORB hosted deposits from deposits hosted on other mafic and ultramafic substrates at sites where the composition of the host rock is not known (Figure 10a). To test the utility of this ratio, a compilation of four groups of substrate types were compiled (Table S2) for which bulk geochemistry of hydrothermal deposits was available: 1) E-MORB (Lucky Strike, Menez Gwen, and Endeavour); 2) N-MORB (TAG, Snake Pit, and Broken Spur); 3) ultramafic (Rainbow and Logatchev); and 4) mixed mafic and ultramafic (Beebe, Kairei, Yuhuang-1, and Daxi; Figure 10a,b). The median Ba/Co values are 180, 3, 3, and 0.006 for E-MORB, N-MORB, ultramafic, and mixed mafic/ultramafic groups, respectively (Figure 10b). However, concentrations of Ba and Co can also be significantly affected by temperature during mineral precipitation, with Co associated with high-temperature mineral assemblages and Ba associated with lower-temperature mineral assemblages (Figure 5). Therefore, to test whether changes in Ba/Co values primarily reflect substrate composition or temperature, the ratios are plotted against Cu/Zn, another geochemical proxy for temperature, for the different substrate groups (Figure 10). Elevated Cu values are associated with precipitation of high-temperature chalcopyrite (250-350°C) and high Zn values are associated with precipitation of sphalerite at lower temperatures (<250°C; Figure 5; [START_REF] Hannington | Volcanogenic Massive Sulfide Deposits[END_REF]. For the E-MORB group, the Ba/Co values show a general negative trend, relative to Cu/Zn, which reflects the temperature dependence of both ratios within a group. However, when comparing data from different substrate groups, the Ba/Co shows a trend associated with different substrates that is independent of Cu/Zn (Figure 10). 2006)), Menez Gwen [START_REF] Bogdanov | Chemical Composition of the Hydrothermal Deposits of the Menez Gwen Vent Field (Mid-Atlantic Ridge)[END_REF], and Endeavour [START_REF] Morgan | Ore assays of massive sulfides from three spreading centers[END_REF][START_REF] Samson | Compilation of Information on Polymetallic Sulfide Deposits and Occurrences off the West Coast of Canada[END_REF]Margaret K. Tivey & Delaney, 1986;Margaret Kingston Tivey et al., 1999;[START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF]. N-MORB includes TAG [START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Hannington | The formation of atacamite during weathering of sulfides on the modern seafloor[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Lisitsyn | Hydrothermal formations of the ocean rift zone[END_REF][START_REF] Rona | Active and relict sea-floor hydrothermal mineralization at the TAG hydrothermal field, mid-Atlantic ridge[END_REF][START_REF] Thompson | Active vents and massive sulfides at 26°N (TAG) and 23°N (Snakepit) on the Mid-Atlantic Ridge[END_REF], Snake Pit [START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Honnorez | Mineralogy and chemistry of sulfide deposits drilled from hydrothermal mound of the Snake Pit active field[END_REF][START_REF] Kase | Copper-rich sulfide deposit 23°N, Mid-Atlantic Ridge: Chemical composition, mineral chemistry, and sulfur isotopes[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Fouquet | Tectonic Setting and Mineralogical and Geochemical Zonation in the Snake Pit Sulfide Deposit (Mid-Atlantic Ridge at 23°N)[END_REF][START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF], and Broken Spur [START_REF] Bogdanov | Relict sulfide mounds at the TAG hydrothermal field of the Mid-Atlantic Ridge (26° N, 45° W)[END_REF][START_REF] Bogdanov | Mineralogical -Geochemical Features of Sulfide Ores from the Broken Spur Hydrothermal Vent Field[END_REF][START_REF] Lisitsyn | Noble metals in ore-forming hydrothermal systems of modern oceans[END_REF][START_REF] Peresypkin | On the nature of lipids in hydrothermal formations at the Broken Spur and vent fields of the Mid-Atlantic Ridge[END_REF][START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF]. Ultramafic-hosted includes Rainbow [START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF] and Logatchev (Bogdanov et

Accepted Article

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems , 1997;[START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Lisitsyn | Noble metals in ore-forming hydrothermal systems of modern oceans[END_REF][START_REF] Mozgova | Mineralogy and chemistry of massive sulfides from the Logatchev Hydrothermal Field (14°45' N Mid-Atlantic Ridge)[END_REF][START_REF] Murphy | A gold-copper association in ultramafic-hosted hydrothermal sulfides from the Mid-Atlantic ridge[END_REF][START_REF] Peresypkin | On the nature of lipids in hydrothermal formations at the Broken Spur and vent fields of the Mid-Atlantic Ridge[END_REF]. Mixed mafic and ultramafic includes Beebe [START_REF] Webber | Geology, sulfide geochemistry and supercritical venting at the Beebe Hydrothermal Vent Field, Cayman Trough[END_REF], Kairei [START_REF] Wang | Mineralogy and geochemistry of hydrothermal precipitates from Kairei hydrothermal field, Central Indian Ridge[END_REF], Yuhuang-1 [START_REF] Liao | Bulk geochemistry, sulfur isotope characteristics of the Yuhuang-1 hydrothermal field on the ultraslow-spreading Southwest Indian Ridge[END_REF], and Daxi [START_REF] Wang | The Daxi Vent Field: An active mafic-hosted hydrothermal system at a non-transform offset on the slowspreading Carlsberg Ridge, 6°48′N[END_REF]. Data in Table S2.

29 al.

Conclusions

The hydrothermal deposits at Lucky Strike are composed of a mineral assemblage typical of basalthosted mid-ocean ridge hydrothermal deposits, except for the presence of abundant barite. Principal component analysis discriminates the minor and trace element distribution between high and low temperature mineral assemblages and the precipitation of minerals that result from direct interaction with seawater. The mineralogy and geochemical composition of the off-axis Capelinhos site is similar to the deposits from the main field. However, the sulfur isotopic composition of Capelinhos is heavier by ~3.5‰ compared to the rest of Lucky Strike. These differences reflect variations in length and/or permeability in the pathways of the uprising hydrothermal fluid and distinct fluid/rock interactions at each of these sites, including evidence from S isotope modelling of extensive subseafloor marcasite/pyrite mineralization below the main site. Here, S isotopic data corroborate previously reported variations in fluid chemistry between different sites that indicate that >80% of the available H2S in the ascending hydrothermal fluid precipitates in a stockwork zone below the seafloor. These results highlight that the interpretation of S isotope compositions for hydrothermal deposits along mid-ocean ridges cannot necessarily be interpreted simply within the context of a two-component mixing model between mantle-and seawater-derived sulfur sources, and that subseafloor mineralization and isotopic exchange can also affect the isotopic compositions of surficial sulfide deposits.

The Ba/Co ratio of hydrothermal deposits provides a temperature-independent geochemical tool to discriminate the composition of the substrate beneath hydrothermal vent fields at mid-ocean ridges, especially E-MORB hosted site that have a distinct elevated Ba/Co ratio. High Ba/Co ratios at Lucky Strike and Menez Gwen indicate an E-MORB substrate associated with the Azores hotspot. In contrast, low Ba/Co ratios, are associated with hydrothermal sites hosted in N-MORB, ultramafic, and sites that have a mixed mafic and ultramafic substrates.

Accepted Article

This article is protected by copyright. All rights reserved.

MLSHF-White Castle

Accepted Article

This article is protected by copyright. All rights reserved.

Figure 1 .

 1 Figure 1. Location of the Lucky Strike segment on the Mid-Atlantic Ridge and its geotectonic context. The black outline highlights the bathymetric high of the Azores plateau and the yellow circle is the location of the Azores hotspot[START_REF] Gente | Interaction between the Mid-Atlantic Ridge and the Azores hot spot during the last 85 Myr: Emplacement and rifting of the hot spotderived plateaus[END_REF].

Figure 2 .

 2 Figure 2. Segment scale bathymetric map of Lucky Strike (~40 m resolution). Red rectangle shows the area of study (Figure 3a). White solid lines show approximate extent of the Lucky Strike Seamount. The white dashed lines are the axial valley walls. NTO are non-transform offsets.Bathymetry from the Sudaçores cruise[START_REF] Cannat | Mid-Atlantic Ridge-Azores hotspot interactions: Along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago[END_REF][START_REF] Escartín | Crustal thickness of Vshaped ridges south of the Azores: Interaction of the Mid-Atlantic Ridge (36°-39°N) and the Azores hot spot[END_REF].

Figure 3 .

 3 Figure 3. A) Outlines of the main hydrothermal areas from the Lucky Strike hydrothermal system.High temperature venting of 340°C (Tmax) occurs at the main Lucky Strike hydrothermal field and 324°C fluid (Tmax) at Capelinhos. Ewan is a site of diffuse venting[START_REF] Barreyre | Temporal variability and tidal modulation of hydrothermal exit-fluid temperatures at the Lucky Strike deep-sea vent field, Mid-Atlantic Ridge[END_REF][START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF]. The dashed red lines show the volcanic rifted structures v2 (higher degree of rifting) to the north and v1 in the south. White dashed outline is a fossil lava lake. B) Venting of 222°C fluid (Tmax);[START_REF] Damm | The geochemical controls on vent fluids from the Lucky Strike vent field , Mid-Atlantic Ridge[END_REF] at a sulfide chimney at the Sintra vent complex within the main Lucky Strike hydrothermal field. The length of the robotic arm is ~75 cm. C) Chimneys and high-temperature venting at the Capelinhos site[START_REF] Chavagnac | Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid-Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry From the Newly Discovered Capelinhos Vent[END_REF]. The temperature probe is ~1 m long. Bathymetry sources:[START_REF] Ondréas | Recent volcanic events and the distribution of hydrothermal venting at the Lucky Strike hydrothermal field[END_REF] and[START_REF] Escartín | Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge): Distribution, heatflux, and geological controls[END_REF].

Figure 4 .

 4 Figure 4. The main mineral assemblages of hydrothermal deposits at Lucky Strike. A) Typical chimney sample from Tour Eiffel (MOM14-579-ROC1) with sulfate and Fe-sulfide minerals dominating the exterior, and chalcopyrite and sphalerite in the interior, and lining the open fluid conduits (in white dashed lines). B) Sample collected from the side of the Sintra (MOM12-502-ROC1) edifice, with abundant barite, anhydrite, marcasite, and sphalerite. C) Chimney fragment from Tour Eiffel (MOM13-532-ROC2), dominated by marcasite and chalcopyrite. D) Typical mineralogical transition, from barite and marcasite towards the exterior, to sphalerite and chalcopyrite lining an interior high-temperature fluid conduit. Sample from the Tour Eiffel site (MOM14-579-ROC1). E) The same photomicrograph as D but under transmitted, crossed polarized light. F) Supergene alteration consisting of atacamite and goethite occurring on outer chimney walls. Sample from the Chimiste site (MOM15-PL607_ROC3). G) Supergene alteration, with minor bornite and covellite replacing chalcopyrite. Sample from the Capelinhos site (MOM14-PL583-ROC4). H) Sphalerite overgrown by chalcopyrite in a vent orifice and a second

Figure 5 .

 5 Figure 5. Principal component analysis of bulk rock geochemistry (black dots) from the main Lucky Strike and Capelinhos hydrothermal sites. Elements in squares are associated with high temperature sulfide minerals; elements in upright triangles are associated with lower temperature sulfide minerals; elements in inverted triangles are associated with sulfate minerals; elements in ovals are associated with seawater or redox sensitive (Mo, V, and Ni).

Figure 6 .

 6 Figure 6. Thin section photomicrographs (plane polarized reflected light) showing locations of δ 34 S spot analysis: A) Partially infilled vent orifice with a low-temperature assemblage of atolllike marcasite with plumose marcasite overgrowths, barite and sphalerite, overprinted by hightemperature euhedral chalcopyrite. Sample from the Tour Eiffel site (MOM14-579-ROC1). B) Plumose marcasite overprinted by euhedral chalcopyrite. Samples from the Isabel site (MOM15-PL607-ROC5). C) Atoll-like marcasite overprinted by massive chalcopyrite. Sample from the Sintra site (MOM11-452-ROC3). D) Euhedral pyrite overprinted by euhedral chalcopyrite. Sample from the White Castle site (MOM15-603-ROC6). E) Anhedral marcasite with later anhedral chalcopyrite infilling. Sample from the Capelinhos site (MOM14-583-ROC1-S). F) Atoll-like marcasite overprinted by massive marcasite. Sample from Capelinhos (MOM14-PL583-ROC4).

Figure 7 .

 7 Figure 7. Box plot of in situ sulfur isotope δ 34 S values for marcasite, pyrite, and chalcopyrite at Lucky Strike, divided by sites. Box and whiskers of quartiles, boxes represent 50% of the data, median is between the boxes, and black line is the average.

Figure 8 .

 8 Figure 8. Summary sketch of the location and faulting at the Lucky Strike hydrothermal field. The stockwork is interpreted based on the sulfur isotope data from this study. Axial magma chamber (~3.5 km depth) outline from Combier et al. (2015) and layer 2A from Seher et al. (2010), both derived from seismic reflection data.

Figure 10 .

 10 Figure10. A) Ratios from selected SMS deposits grouped according to host rock in mid-ocean ridges. Ba/Co vs Cu/Zn. Ba/Co ratio used as a proxy for proximity to a hotspot, Cu/Zn used as a proxy of temperature of formation. B) Box and whisker plots of quartiles for Ba/Co and Cu/Zn (boxes with black line for median, black dot for mean, and number of samples). E-MORB includes data from Lucky Strike (this study and[START_REF] Bogdanov | Hydrothermal sulfide deposits of the Lucky Strike vent field, Mid-Atlantic Ridge[END_REF]), Menez Gwen[START_REF] Bogdanov | Chemical Composition of the Hydrothermal Deposits of the Menez Gwen Vent Field (Mid-Atlantic Ridge)[END_REF], and Endeavour[START_REF] Morgan | Ore assays of massive sulfides from three spreading centers[END_REF][START_REF] Samson | Compilation of Information on Polymetallic Sulfide Deposits and Occurrences off the West Coast of Canada[END_REF] Margaret K. Tivey & Delaney, 1986; Margaret Kingston Tivey et al., 1999;[START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF]. N-MORB includes TAG[START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Hannington | The formation of atacamite during weathering of sulfides on the modern seafloor[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Lisitsyn | Hydrothermal formations of the ocean rift zone[END_REF][START_REF] Rona | Active and relict sea-floor hydrothermal mineralization at the TAG hydrothermal field, mid-Atlantic ridge[END_REF][START_REF] Thompson | Active vents and massive sulfides at 26°N (TAG) and 23°N (Snakepit) on the Mid-Atlantic Ridge[END_REF], Snake Pit[START_REF] Hannington | Comparative mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean ridges[END_REF][START_REF] Honnorez | Mineralogy and chemistry of sulfide deposits drilled from hydrothermal mound of the Snake Pit active field[END_REF][START_REF] Kase | Copper-rich sulfide deposit 23°N, Mid-Atlantic Ridge: Chemical composition, mineral chemistry, and sulfur isotopes[END_REF][START_REF] Krasnov | Detailed geological studies of hydrothermal fields in the North Atlantic[END_REF][START_REF] Fouquet | Tectonic Setting and Mineralogical and Geochemical Zonation in the Snake Pit Sulfide Deposit (Mid-Atlantic Ridge at 23°N)[END_REF][START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF], and Broken Spur[START_REF] Bogdanov | Relict sulfide mounds at the TAG hydrothermal field of the Mid-Atlantic Ridge (26° N, 45° W)[END_REF][START_REF] Bogdanov | Mineralogical -Geochemical Features of Sulfide Ores from the Broken Spur Hydrothermal Vent Field[END_REF][START_REF] Lisitsyn | Noble metals in ore-forming hydrothermal systems of modern oceans[END_REF][START_REF] Peresypkin | On the nature of lipids in hydrothermal formations at the Broken Spur and vent fields of the Mid-Atlantic Ridge[END_REF][START_REF] Toffolo | Seafloor massive sulfides from mid-ocean ridges: Exploring the causes of their geochemical variability with multivariate analysis[END_REF]. Ultramafic-hosted includes Rainbow[START_REF] Marques | Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system : From serpentinization to the formation of Cu-Zn-(Co)-rich massive sulfides[END_REF] and Logatchev(Bogdanov et

Table 1

 1 summarizes 28-element geochemical analysis of 19 sulfide-rich samples from Lucky Strike and sulfide-rich hydrothermal precipitates on the temperature probes. Notable results from the chimney samples include average base metal concentrations of 7.2 wt.% Cu, with a range of 0.012-26.4 wt.% Cu, 5.9 wt.% Zn, with a range of 0.037-37.4 wt.% Zn, 6.5 wt.% Ba, with a range of 0.027-44.4 wt.% Ba, and 630 ppb Au, with a range of 8-2030 ppb Au. Additionally, concentrations of Sr of up to 5940 ppm, Mo of up to 351 ppm, and Se with of up to 2570 ppm.

Rare earth element concentrations are generally below detection limits. There are no significant elemental enrichments or depletions associated with the different vent sites at Lucky Strike. The composition of the temperature probe precipitates have notably lower concentrations of Zn, Pb, Ba, Au, and Ag.

Table 1 .

 1 (continued) Chemical composition of hydrothermal samples from Lucky Strike vent field (see supporting information TableS1for full dataset that includes additional elements that were largely below detection limit).

	Analyte Symbol	Latitude	Longitude	Description	IGSN	Cu (wt.%)	Zn (wt.%)	Pb (ppm)	Fe (wt.%)	S (wt.%)	Si (wt.%)	Al (wt.%)	Ca (wt.%)	Na (wt.%)	Mg (wt.%)	Ba (ppm)	Sr (ppm)	Mo (ppm)
	Detection Limit					0.0002	0.001	0.8	0.01	0.01	0.01	0.01	0.01	0.001	0.01	20	3	1
	Analysis Method					FUS	INAA	FUS	INAA	FUS	FUS	FUS	FUS	INAA	FUS	INAA	FUS	FUS
	Capelinhos (1678 mbsl)
	MOM14-583-ROC1-S	37.28973	-32.281042	Block from the base of Capelinhos edifice	CNRS0000007069	5.4	1.01	113	21.8	27	11.9	0.04	0.09	0.12	<0.01	45200	1150
	MOM14-PL583-ROC4	37.289418	-32.263983	Fragment A of active chimney	CNRS0000007072	5.09	2.49	193	42.4	50.1	0.04	0.03	0.48	0.08	<0.01	1760	97
	MOM14-PL583-ROC4	37.289418	-32.263983	Fragment B of active chimney	CNRS0000007072	11.4	1.53	137	40	45.3	0.22	0.11	0.05	0.22	<0.01	330	20
	MOM13-528-ROC1-S	37.289467	-32.263972	Block from the base of Capelinhos edifice	N/A	0.0459	6.64	716	35.4	46.9	0.17	0.05	0.07	0.16	0.01	12900	737
	Y3 (1730 mbsl)
	MOM11-454-ROC7	37.291867	-32.277817	Base of small active chimney	CNRS0000007017	4.02	7.57	489	31.5	41.5	1.56	0.5	0.19	0.3	0.02	19300	850	318
	White Castle (1705
	mbsl)
	MOM15-603-ROC5	37.28973	-32.281042	Block from active edifice	CNRS0000007099	1.41	27.6	887	12.3	34.7	2.94	0.64	0.07	0.25	0.03	4960	239	121
	MOM15-603-ROC6	37.28973	-32.281042	Block from active edifice	CNRS0000007100	10.1	0.614	209	27.3	35.8	5.45	0.36	0.1	0.18	0.04	38300	1700	351
	Off axial graben to the
	W (1612 mbsl)
	MOM15-605-ROC2	37.295229	-32.284963	From inactive site	CNRS0000007103	0.035	0.048	31.3	0.56	6.29	0.6	<0.01	0.16	0.12	0.02	444000	5940	7
	Tour Eiffel (1696 mbsl)
	MOM11-457-ROC8	37.289033	-32.275667	Small inactive Eiffel chimney W of Tour	CNRS0000007018	1.52	37.4	823	17.5	38.5	0.95	0.08	0.1	0.06	<0.01	34500	1040
	MOM14-579-ROC1	37.290722	-32.281038	Small inactive chimney	CNRS0000007062	7.36	7.62	454	28.5	36.7	5.36	0.61	0.1	0.19	0.01	23800	667	167
	MOM13-532-ROC1	37.288933	-32.275417	Block in the E slope of Tour Eiffel		0.012	0.128	746	26.3	33.2	4.63	<0.01	0.1	0.14	<0.01	99400	2080
	MOM13-532-ROC2	37.288933	-32.275417	Block of sulfide at base of Tour Eiffel	N/A	19.4	0.037	19.9	31.7	41.3	0.51	0.18	0.07	0.28	0.05	950	48
	Site 85 m SW of Tour
	Eiffel (1691 mbsl)

This article is protected by copyright. All rights reserved.

manuscript submitted to Geochemistry, Geophysics, Geosystems

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems 14 This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

Table 2 .

 2 In situ sulfur isotope compositions of marcasite (mrc), pyrite (py), and chalcopyrite (cpy) from Lucky Strike. SEM= standard error of the mean.

		Mineral	Texture	Mineral assemblage	δ 34 S (‰)	SEM
	Capelinhos site
	MOM14-PL583-ROC4_Cpy1	Cpy	euhedral/massive	marcasite-chalcopyrite	7.7	0.5
	MOM14-PL583-ROC4_Cpy3	Cpy	massive	chalcopyrite	6.3	0.2
	MOM14-PL583-ROC4_Cpy1	Cpy	massive	chalcopyrite	6.5	0.2
	MOM14-PL583-ROC4_Cpy2	Cpy	massive	chalcopyrite	6.5	0.2
	MOM14-583-ROC1-S _Cpy1	Cpy	euhedral	marcasite-chalcopyrite	7.2	0.3
	MOM14-583-ROC1-S _Cpy2	Cpy	euhedral/massive	marcasite-chalcopyrite	4.7	0.6
	MOM13-528-ROC1-S_Cp1	Cpy	cpy disease	sphalerite-chalcopyrite	8.7	0.5
	MOM13-528-ROC1-S_Mrc2	Mrc	plumose	marcasite-barite-sphalerite	3.4	0.3
	MOM13-528-ROC1-S_Mrc1	Mrc	plumose	marcasite-barite-sphalerite	3.9	0.4
	MOM14-583-ROC1-S_Mrc2	Mrc	massive/subhedral	marcasite-chalcopyrite	5.2	0.3
	MOM14-583-ROC1-S_Mrc1	Mrc	atoll/ring	marcasite-chalcopyrite	4.0	0.8
	MOM14-PL583-ROC4_Mrc1	Mrc	atoll/ring	marcasite	1.7	0.6
	MOM14-PL583-ROC4_Mrc2	Mrc	euhedral/massive	marcasite	4.4	0.7
	Main Field-Chimiste
	MOM15-PL607_ROC3_Mrc1	Mrc	euhedral	marcasite	-0.5	0.3
	Main Field-Isabel
	MOM15-PL607_11_ROC5_Cpy1	Cpy	massive	marcasite-chalcopyrite	2.8	0.2
	MOM15-PL607_11_ROC5_Cpy2	Cpy	euhedral	marcasite-chalcopyrite	2.8	0.5
	MOM15-PL607_11_ROC5_Mrc1	Mrc	colloform	marcasite-chalcopyrite	-2.4	0.3
	MOM15-PL607_11_ROC5_Mrc2	Mrc	plumose	marcasite-chalcopyrite	-0.7	0.4
	Main Field-Sintra
	MOM11-452-ROC3_Cpy2	Cpy	euhedral/massive	chalcopyrite-sphalerite	2.0	0.3
	MOM11-452-ROC3_Cpy1	Cpy	euhedral/massive	chalcopyrite-sphalerite	3.3	0.4
	MOM11-452-ROC3_Cpy3	Cpy	euhedral/massive	chalcopyrite	2.1	0.3
				chalcopyrite-marcasite-
	MOM11-452-ROC2_Cpy2	Cpy	massive	covellite	4.7	0.4
				chalcopyrite-marcasite-
	MOM11-452-ROC2_Cpy1	Cpy	massive	covellite	6.0	0.4
	MOM11-452-ROC3_Mrc1	Mrc	atoll/ring	marcasite-chalcopyrite	-0.7	0.3
	MOM11-452-ROC1_Mrc2	Mrc	colloform	marcasite-barite	-0.6	0.4
	MOM12-502-ROC1_Mrc1	Mrc	colloform	marcasite-barite	1.1	0.5
	MOM11-452-ROC1_Mrc1	Mrc	colloform	marcasite-barite	1.1	0.6
	MOM11-452-ROC2_Mrc1	Mrc	euhedral	marcasite-chalcopyrite	0.9	0.3
	Main Field-Tour Eiffel
	MOM13-532-ROC2_Cpy1	Cpy	massive	marcasite-chalcopyrite	4.3	0.3
	MOM11-457-ROC8_Cpy1	Cpy	massive	chalcopyrite-sphalerite	4.8	0.3
	MOM14-579-ROC1_Cpy3	Cpy	euhedral	chalcopyrite-sphalerite	5.3	0.4
	MOM13-532-ROC2_Mrc1	Py	euhedral/massive	marcasite-chalcopyrite	1.6	0.3
	MOM12-504-ROC1_Mrc1	Mrc	colloform	barite-marcasite	-0.3	0.6

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

4.2. In situ sulfur isotopes

Table

2

summarizes results from in situ sulfur isotope measurements for marcasite and chalcopyrite (Figure

  Zn (wt.%) Pb (ppm) Fe (wt.%) S (wt.%) Si (wt.%) Al (wt.%) Ca (wt.%) Na (wt.%) Mg (wt.%) Ba (ppm) Sr (ppm) Mo (ppm) V (ppm) Ni (ppm) Co (ppm) Se (ppm) Au (ppb) Ag (ppm) As (ppm) Ga (ppm) Ge (ppm) Sb (ppm) Cd (ppm) Tl (ppm) In (ppm) Sn (ppm) Mn (ppm)

	MOM15-603-ROC6_Cpy1	Cpy	euhedral	chalcopyrite-sphalerite	3.1	0.4
	MOM15-603-ROC6_Mrc1	Py	euhedral	marcasite	1.5	0.3
	MLSHF-Y3
	LS-BS-WHOI_Cpy3	Cpy	euhedral	chalcopyrite-sphalerite	1.0	0.3
	LS-BS-WHOI_Cpy1	Cpy	euhedral	chalcopyrite-sphalerite	1.8	0.4
	LS-BS-WHOI_Cpy2	Cpy	euhedral	chalcopyrite-sphalerite	1.8	0.5
	MOM11-454-ROC7_Cpy1 LS-BS-WHOI_Mrc1 Analyte Symbol Cu (wt.%) Detection Limit Cpy euhedral chalcopyrite-sphalerite 3.7 0.4 Mrc plumose marcasite-barite -1.0 0.3 Latitude Longitude Description IGSN 0.0002	0.001	0.8	0.01	0.01	0.01	0.01	0.01	0.001	0.01	20	3	1	5	10	0.1	0.5	2	2	1	0.2	0.7	0.1	2	0.1	0.2	0.5	3
	MOM11-454-ROC7_Mrc1 Analysis Method	Mrc	plumose	marcasite	-2.5	0.2	FUS	INAA	FUS	INAA	FUS	FUS	FUS	FUS	INAA	FUS	INAA	FUS	FUS	FUS	FUS	INAA	INAA	INAA	INAA	INAA	FUS	FUS	INAA	FUS	FUS	FUS	FUS	FUS
	MOM11-454-ROC7_Mrc2 Capelinhos (1678 mbsl) Py	plumose/euhedral	marcasite	-0.8	0.3
	MOM14-583-ROC1-S 37.28973 -32.281042 MOM14-PL583-ROC4 37.289418 -32.263983 MOM14-PL583-ROC4 37.289418 -32.263983 MOM13-528-ROC1-S 37.289467 -32.263972 Y3 (1730 mbsl) MOM11-454-ROC7 37.291867 -32.277817 White Castle (1705 mbsl) MOM15-603-ROC5 37.28973 -32.281042 MOM15-603-ROC6 37.28973 -32.281042 Off axial graben to the W (1612 mbsl) MOM15-605-ROC2 37.295229 -32.284963 Tour Eiffel (1696 mbsl) MOM11-457-ROC8 37.289033 -32.275667 MOM14-579-ROC1 37.290722 -32.281038 MOM13-532-ROC1 37.288933 -32.275417 Block in the E slope of Tour Eiffel Block from the base of Capelinhos edifice Fragment A of active chimney Fragment B of active chimney Block from the base of Capelinhos edifice Base of small active chimney Block from active edifice Block from active edifice From inactive site Small inactive chimney W of Tour Eiffel Small inactive chimney MOM13-532-ROC2 37.288933 -32.275417 Block of sulfide at base of Tour Eiffel Site 85 m SW of Tour Eiffel (1691 mbsl) MOM12-504-ROC1 37.288583 -32.276333 Block in inactive area 85 m SW of Tour Eiffel Sintra (1630 mbsl) MOM11-452-ROC1 37.292083 -32.274717 Small inactive chimney on sulfide-rich basement at the base of Sintra MOM11-452-ROC2 37.292083 -32.2747 Fragments of inactive chimney MOM11-452-ROC3 37.292033 -32.274717 Fragments of inactive chimney MOM12-502-ROC1 37.292167 -32.2750 Active chimney Isabel (1703 mbsl) MOM15-PL607_ROC5 37.28912 -32.277405 Sulfide block Chimiste (1687 mbsl) MOM15-PL607_ROC3 37.289291 -32.276545 Sulfide block Temperature probe precipitates Cyprès (1740 mbsl) MOM14-HN29008-ROCK 37.290787 -32.280972 Precipitate on temperature probe Crystal (1730 mbsl) HT010-CR12 37.29088 -32.28202 Precipitate on temperature probe Cimendef (1702 mbsl) MOM14-HT007-ROCK 37.288083 -32.275838 Precipitate on temperature probe Y3 (1730 mbsl) LS-BS-WHOI 37.29187 -32.27785 Precipitate on temperature probe	CNRS0000007069 CNRS0000007072 CNRS0000007072 N/A CNRS0000007017 CNRS0000007099 CNRS0000007100 CNRS0000007103 CNRS0000007018 CNRS0000007062 N/A CNRS0000007053 CNRS0000007011 CNRS0000007012 CNRS0000007013 CNRS0000007051 CNRS0000007108 CNRS0000007106 N/A N/A N/A N/A	5.4 5.09 11.4 0.0459 4.02 1.41 10.1 0.035 1.52 7.36 0.012 19.4 1.02 2.45 25.6 26.4 0.036 13.5 1.27 8.5 2.41 5.25 Accepted Article 1.01 113 2.49 193 1.53 137 6.64 716 7.57 489 27.6 887 0.614 209 0.048 31.3 37.4 823 7.62 454 0.128 746 0.037 19.9 10.8 502 0.554 993 0.593 379 1.57 306 5.08 541 0.22 177 0.562 354 0.049 8.1 2.12 230 0.098 18.2 201 15.2 2.13	21.8 42.4 40 35.4 31.5 12.3 27.3 0.56 17.5 28.5 26.3 31.7 11.2 38.8 31.9 26.7 4.74 35.1 30.3 44.3 10.3 44.8 30.1	27 50.1 45.3 46.9 41.5 34.7 35.8 6.29 38.5 36.7 33.2 41.3 17.7 38.1 37.4 33.5 9.41 40.3 38.6 48.5 29.2 50.8 35.6	11.9 0.04 0.22 0.17 1.56 2.94 5.45 0.6 0.95 5.36 4.63 0.51 13.6 0.91 0.32 1.77 0.3 0.51 12.3 0.08 0.42 0.22 3.27	0.04 0.03 0.11 0.05 0.5 0.64 0.36 <0.01 0.08 0.61 <0.01 0.18 0.28 0.15 0.15 0.26 <0.01 0.23 0.19 0.03 0.17 0.09 0.24	0.09 0.48 0.05 0.07 0.19 0.07 0.1 0.16 0.1 0.1 0.1 0.07 0.15 0.84 0.04 0.06 0.17 0.05 0.04 0.34 17.4 1 0.13	0.12 0.08 0.22 0.16 0.3 0.25 0.18 0.12 0.06 0.19 0.14 0.28 0.38 0.41 0.21 0.21 0.29 0.23 0.2 0.05 0.21 0.07 0.1	<0.01 <0.01 <0.01 0.01 0.02 0.03 0.04 0.02 <0.01 0.01 <0.01 0.05 0.03 0.11 0.02 0.03 <0.01 0.03 <0.01 0.02 0.07 0.04 <0.01	45200 1760 330 12900 19300 4960 38300 444000 34500 23800 99400 950 112000 14200 310 2870 381000 380 270 <20 7420 560 32300	1150 97 20 737 850 239 1700 5940 1040 667 2080 48 1420 407 24 41 5110 23 20 36 2100 132 1360	33 37 40 69 318 121 351 7 59 167 25 22 66 67 100 59 11 267 69 6 444 11 212	<5 <5 9 <5 110 <5 51 6 6 122 <5 12 35 131 20 16 <5 44 <5 <5 57 <5 58	<10 10 10 10 10 <10 30 10 10 40 20 10 20 20 10 10 <10 10 20 60 1450 20 30	277 158 258 14.1 337 64.6 604 7.4 33 107 48.5 167 50.6 467 225 47.5 8.5 409 89.2 559 101 86.8 198	<0.5 131 150 <0.5 127 42.6 237 <0.5 <0.5 179 <0.5 2570 <0.5 69.9 346 106 <0.5 907 28.9 227 70.6 385 490	258 256 237 323 625 748 205 8 2030 724 309 73 1750 1340 1010 677 369 539 496 37 189 47 228	22 21 22 39 88 152 9 <2 278 76 <2 <2 165 49 94 59 89 44 59 6 28 <2 52	128 291 229 236 307 277 142 14 346 387 449 99 642 635 223 242 168 268 477 85 97 96 120	27.5 27.4 15 51.4 45.8 63.8 8.2 1.1 354 62.6 1.7 1.7 55.3 46.5 36.5 28 10.4 5.1 3.4 0.7 12.2 1.4 17.8	6.8 14.8 10.8 22.8 33.2 60.8 21.9 3.4 68.2 29.8 23.1 5.7 43 19.9 19.5 24.1 50.9 6.9 8.1 5.1 9.7 5.8 19.9	11.4 15 11.4 49.9 23.7 50 5 0.8 166 36.9 2.3 1.6 82.8 39 19 28 29.5 6.3 9.6 0.5 12.4 1.1 8.3	43 55 30 213 288 1250 17 <2 1700 288 4 <2 291 9 25 59 98 6 27 <2 122 3 92	5.4 16.2 5.5 61.9 44 27.6 10.7 <0.1 42.6 38.5 151 1.2 21.6 23.4 6.5 13.4 36.9 9.8 18.4 <0.1 9.2 1.3 21	10.1 2.6 6 1 1.4 0.7 3.4 <0.2 5.7 4.2 <0.2 2.5 0.6 12.7 10.5 6.9 <0.2 6.3 0.3 8.4 2.5 1.7 3.1	3.7 5.3 3.3 1 2.5 3.5 2.3 1.7 1.1 2.3 1 6.3 0.6 1.1 4.2 1.6 0.9 5.9 1 17.7 3 2.2 2.3	55 76 38 91 634 464 193 369 424 349 205 60 1240 1830 113 153 65 211 353 11 92 25 341

This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

Acknowledgments

This work was supported by the Canada Research Chair Program, an NSERC Discovery Grant, and RDC Leverage Grant to J.W. Jamieson. DSM acknowledges support from the NSERC iMAGE-CREATE program.

Data availability statement

All the geochemical data (bulk geochemistry and in situ sulfur isotope) is included in this paper and in the Supporting Information and can be also accessed at https://doi.org/10.5281/zenodo.6035032 [START_REF] Sánchez-Mora | Bulk geochemistry and in situ sulfur isotopes of hydrothermal deposits from the Lucky Strike vent field[END_REF].

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems

Accepted Article

This article is protected by copyright. All rights reserved. manuscript submitted to Geochemistry, Geophysics, Geosystems