C Defouilloy
email: author.defouilloy@ipgp.fr

P Cartigny

N Assayag

F Moynier

J.-A Barrat

High-precision sulfur isotope composition of enstatite meteorites and implications of the formation and evolution of their parent bodies

In order to better understand the formation and evolution of their parent bodies, the three isotope ratios of sulfur were analyzed in 33 enstatite meteorites (24 enstatite chondrites and

INTRODUCTION

Enstatite meteorites comprise two groups of meteorites: enstatite chondrites, which are undifferenciated (primitive) meteorites, and aubrites, which are also referred to as enstatite achondrites, and are differentiated material.

As shown by their mineral assemblages and compositions enstatite meteorites are the most reduced meteorites (Mason 1965[START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF][START_REF] Rubin | The Blithfield meteorite and the origin of sulfide-rich, metal-poor clasts and inclusions in brecciated enstatite chondrites[END_REF][START_REF] Brett | Enstatite chondrites and enstatite achondrites (aubrites) were not derived from the same parent body[END_REF][START_REF] Weisberg | The unequilibrated enstatite chondrites[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF]. This is attested by their major silicate phase which is nearpure enstatite (≈ 50 wt% of total sample), with FeO < 1%. Their amount of FeNi metal (≈ 25 wt%) is higher than in other chondrite groups and the metal phase contains up to 2 wt% Si.

Other important phases include troilite and plagioclase. The exceptionally reduced environment of their formation leads most lithophile elements to behave as chalcophile [START_REF] El Goresy | Qingzhen and Yamato-691: A tentative alphabet for the EH chondrites[END_REF], and therefore to the formation of a large variety (0.1 to 1 %) of unusual sulphides, including oldhamite (CaS), niningerite ([Mg, Fe, Mn]S), alabandite (MnS) and rare minerals such as osbornite (TiN), sinoite (Si2N2O), daubreelite (FeCr2S4), caswellsilverite (NaCrS2) and perryite ([Ni,Fe]8 [Si,P]3) are further illustration of their very reduced character.

The enstatite chondrites are commonly subdivided into 2 sub-groups according to their amount of metallic Fe: EH (Fe-rich enstatite chondrites) and EL (Fe-poor enstatite chondrites) [START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF][START_REF] Sears | Formation of E chondrites and aubrites-A thermodynamic model[END_REF], Kallemeyn & Wasson 1983). It is also worth noting that EH are characterised by the occurrence of alabandite, while EL contain niningerite instead as well as various alkali sulfides [START_REF] Lin | A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies[END_REF][START_REF] Weisberg | The unequilibrated enstatite chondrites[END_REF]. In addition, [START_REF] Lin | A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies[END_REF] have given several petrographic evidence that the EH parent body had to form in even more reduced conditions than the EL parent body, with a lower oxygen and a higher H2S fugacity, resulting in a higher Si content in kamacite and perryite, and alkali enrichment in sulphides in unequilibrated EL3 compared to their EH3 counterparts. Like other chondrites, enstatite chondrites present various degrees of metamorphism, from the more primitive group, noted 3, to the most metamorphosed, noted 6 (or 7). Yet, due to their very specific mineralogies, it can be challenging to assess precisely the exact degree of metamorphism and uncertainty remains regarding the classification of enstatite chondrites [START_REF] Quirico | A reappraisal of the metamorphic history of EH3 and EL3 enstatite chondrites[END_REF]. It is to be noted that there are no hydrous metamorphosed enstatite. This is primarily the consequence that no hydrous phase exists, H being dissolved in the metal phase.

Interestingly, enstatite chondrites are the only undifferentiated meteorites to possess a wellidentified differentiated counterpart, the aubrites. Aubrites are for the most part fragmental breccias or regolith impact breccias, with the exception of 6 samples representing impact melts [START_REF] Casanova | Composition of metal in aubrites: Constraints on core formation[END_REF], Lorenzetti et al. 2002[START_REF] Miura | Noble gas and oxygen isotope studies of aubrites: A clue to origin and histories[END_REF]. Besides enstatite, their main minerals are albitic plagioclase, diopisde and forsterite. Based on similar O isotopic compositions and major element content, they are thought to originate from an enstatite chondrite-like parent body, but neither from the EH nor the EL parent bodies [START_REF] Keil | Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies[END_REF]. No study has reported a comparison of O fugacity in aubrites with EL and EH. However, their mineralogical composition and possibly complementary Zn isotopic composition tends to show that aubrites are closer to EL than EH [START_REF] Watters | Aubrites-Their origin and relationship to enstatite chondrites[END_REF][START_REF] Rubin | The Blithfield meteorite and the origin of sulfide-rich, metal-poor clasts and inclusions in brecciated enstatite chondrites[END_REF][START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF].

The origin of enstatite meteorites and their parent bodies and the genetic relationships between all the sub-groups remain partially unsolved today. There are several arguments in favour of a common origin of enstatite chondrites. For example, they have several remarkable features that distinguish them from any other meteorite groups. They have a distinct mineralogy, with a wide variety of sulfides and metals, reflecting their highly reduced environments of formation. They also have similar oxygen isotopic compositions [START_REF] Clayton | Oxygen isotope studies of achondrites[END_REF][START_REF] Herwartz | Identification of the giant impactor Theia in lunar rocks[END_REF]. It is therefore likely that they share a common origin.

Several authors have favoured a common parent body for all the enstatite chondrites, EL and EH (Clayton andMayeda, 1996, Kong et al. 1997). This is corroborated by the fact that they are all completely dry (there are no enstatite chondrites of petrologic types 1 or 2) and the high melting temperature of enstatite. Yet some incompatibilities have been emphasized [START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF][START_REF] Brett | Enstatite chondrites and enstatite achondrites (aubrites) were not derived from the same parent body[END_REF][START_REF] Lin | A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies[END_REF][START_REF] Keil | Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies[END_REF]. In particular, [START_REF] Lin | A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies[END_REF] showed that the chemical and petrography of the EH and EL were incompatible with a common parent body. EH have a higher Mg/Si ratio than the EL [START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF]). EL and EH also have very distinct cooling rates and heating histories, suggesting distinct parent bodies (Zhang et al. 1995[START_REF] Lin | A comparative study of opaque phases in Qingzhen (EH3) and MacAlpine Hills 88136 (EL3): Representatives of EH and EL parent bodies[END_REF].

The chemical, and isotopic similarities between enstatite meteorites that were previously used as evidence for common parent body are now re-interpreted in terms a common environment of formation for the different parent bodies (as attested by the mineralogy of the meteorites. [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF]). Even though it is now generally assumed that enstatite meteorites originate from at least four different parents bodies -one for the EL, one for the EH, and 2 for the aubrites (one for the Shallowater meteorite, and another parent body for all the other aubrites) -a few studies have pointed out the peculiarity of EL6 compared to EL3 and EH in their REE content [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF]) and zinc isotopic composition [START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF], leading to the question whether they could originate from an additional distinct parent body.

Both enstatite meteorites and the Earth (as well as other terrestrial planets) formed in a reduced environment, which suggests a possible link between them [START_REF] Javoy | The chemical composition of the Earth: Enstatite chondrite models[END_REF][START_REF] Sanloup | A simple chondritic model of Mars[END_REF]. Isotopic similarities between the Earth and enstatite meteorites are remarkable, the most striking observation being the oxygen isotopic composition [START_REF] Clayton | Oxygen isotopic compositions of enstatite chondrites and aubrites[END_REF][START_REF] Clayton | Oxygen isotope studies of achondrites[END_REF][START_REF] Newton | The oxygen-isotopic record in enstatite meteorites[END_REF][START_REF] Herwartz | Identification of the giant impactor Theia in lunar rocks[END_REF]. Isotopic similarity between the Earth and enstatite meteorites now extend to many additional elements such as Zn [START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF], N [START_REF] Javoy | Stable isotope constraints on a model Earth from a study of mantle nitrogen[END_REF][START_REF] Cartigny | Nitrogen isotopes in peridotitic diamonds from Fuxian, China: the mantle signature[END_REF], Mo [START_REF] Dauphas | The cosmic molybdenum-ruthenium isotope correlation[END_REF]), Ru [START_REF] Dauphas | The cosmic molybdenum-ruthenium isotope correlation[END_REF]), Cr [START_REF] Birck | 53 Mn-53 Cr evolution of the early solar system[END_REF], Trinquier et al. 2007a), Sr [START_REF] Moynier | Sr stable isotope composition of Earth, the Moon, Mars, Vesta and meteorites[END_REF][START_REF] Moynier | Planetary-Scale Strontium Isotopic Heterogeneity and the Age of Volatile Depletion of Early Solar System Materials[END_REF], Ti (Trinquier et al. 2007b) and Ca [START_REF] Valdes | The nature of Earth's building blocks as revealed by calcium isotopes[END_REF]. These similarities has led to the idea that, contrary to first assumptions, the Earth was not built from a majority of ordinary chondrites and carbonaceous chondrites -like material, but primarily from enstatite-like material [START_REF] Javoy | The birth of the Earth's atmosphere: the behaviour and fate of its major elements[END_REF][START_REF] Javoy | The chemical composition of the Earth: Enstatite chondrite models[END_REF]. However, the Mg/Si ratio of bulk enstatite chondrites is much lower than that of BSE, and the Si isotopic ratio measured in all enstatite meteorites is significantly different from Earth [START_REF] Fitoussi | Silicon Isotope Evidence Against an Enstatite Chondrite Earth[END_REF][START_REF] Savage | Silicon isotopic variation in enstatite meteorites: Clues to their origin and Earth-forming material[END_REF], though Dauphas et al. (2015) have recently shown that Mg/Si ratio was dictated by the the condensation sequence of forsterite in the solar nebula.

Earth and enstatite meteorites might also slightly differ in their Ti isotopic composition [START_REF] Trinquier | Origin of Nucleosynthetic Isotope Heterogeneity in the Solar Protoplanetary Disk[END_REF][START_REF] Feng | Excess 36 S in Lawrencite and Nitrogen Isotopic Compositions of Sinoite from Almahata Sitta MS-17 EL3 Chondrite Fragment[END_REF] as well as Ca isotopic composition [START_REF] Simon | Stable calcium isotopic composition of meteorites and rocky planets[END_REF], though the latter was recently proved disputable by [START_REF] Valdes | The nature of Earth's building blocks as revealed by calcium isotopes[END_REF].

Finally, a recent study by [START_REF] Herwartz | Identification of the giant impactor Theia in lunar rocks[END_REF] revealed small but significant differences in the 17 O isotopic compositions of Earth and enstatite meteorites: 59 ± 8 ppm (0.059 ± 0.008 ‰) for EL and 35 ± 10 ppm (0.035 ± 0.01 ‰) for EH. Though it seems undeniable that enstatite meteorites share a lot of features with the Earth, building the Earth solely from enstatite-like material is not free of difficulties.

Sulfur is present in enstatite meteorites in significant quantity (≈ 4-5 wt% S) [START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF]).

Having 4 isotopes ( 32 S, 33 S, 34 S, 36 S), it allows the distinction of equilibrium and kinetic effects and the identification of mass independent isotopic fractionation (MIF). A scarce number of sulfur isotopic compositions have been measured in enstatite chondrites (Gao & Thiemens 1993a) and aubrites [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF], including significant MIF reported in the aubrite Norton County [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF]). To better discuss the differences and relationships between the different groups of enstatite meteorites and to better apprehend the link between the enstatite meteorites and the building material of the Earth, we report the S isotopic composition of 33 enstatite chondrites and aubrites, to create a precise spectrum of the S isotopic variations and possible MIF in all the enstatite-bearing bodies.

SAMPLES AND METHODS

33 samples of enstatite meteorites, from all groups and metamorphism degrees have been analysed: 2 EL3 (Mac 88 136, Mac 02 837), 9 EL6 (Hvittis, Khaipur, Eagle, North West Forest, Lon 94 100, Happy Canyon, EET 92 063, NWA 974, Pillistfer, Atlanta, Blithfield), 2 EL7 (Happy Canyon, Ilafegh 009), 8 EH3 (Indarch, Qinz-Zhan, Gro 95 517, Abee, Kota-Kota, Alha 77 295, Mil 07 028, Itqiy, Sahara 97 096), 3 EH5 (St Sauveur, LA 02 225, St Mark's) and 9 Aubrites (Norton County, Khor Temiki, Shallowater, Bishopville, Cumberland Falls, Aubres, Bustee, Mayo Belwa, Pena Blanca). Two samples, North West Forest (EL6) and Itqiy (EL7-an), did not release any sulfur.

Analytical techniques

Extraction of reduced sulfur

Samples were obtained either as fine powders or as cm-size chunks of rocks that were subsequently crushed into powder. For bulk reduced sulfur extraction about 20 mg of powder was used in each experiment. When enough material was available, a replica or two were processed. The powered samples were poured in a glass reaction vessel with 20 ml of chrome reduction solution (≈ 30 % Cr(III)Cl3 + 15 % Zn + 55 % HCl 0.6 N, see [START_REF] Canfield | The use of chromium reduction in the analysis of reduced inorganic sulfur in sediments and shales[END_REF]). 5 ml of HCl 6N were added to the mixture to ensure an acidic condition, which enhances the reaction rate. The flasks were heated to boiling temperature for 3 hours under a flux of N2. Hydrogen sulfide was swept out with a stream of nitrogen gas, washed in distilled water, and collected in a silver nitrate solution. Ag2S was rinsed with distilled water and then dried for 24 hours.

As detailed previously (e.g. [START_REF] Canfield | The use of chromium reduction in the analysis of reduced inorganic sulfur in sediments and shales[END_REF]) extensive tests on pure FeS2 original material has shown that our settings for the chemical extraction of sulfides ensure a close to 100% yield and do not create any significant fractionation of sulfur isotopes.

Weighed aliquots of Ag2S samples wrapped in Al foils, are introduced in nickel bombs, evacuated and fluorinated with purified F2 at 250° overnight. The reaction releases SF6 which is then purified by cryogenic separation and gas chromatography (1/8 in. diameter column of a 6 ft 5A molecular sieve followed by a 8 ft Haysep Q column. [START_REF] Ono | Mass-dependent fractionation of quadruple stable sulfur isotope system as a new tracer of sulfur biogeochemical cycles[END_REF]. Purified SF6 is then quantified using a capacitance manometer (to check for fluorination yield) and analyzed by mass spectrometry.

Several large samples were obtained, allowing the isotopic composition of oldhamite (CaS) to be investigated. CaS is a fragile sulphide, easily reacting with water to produce H2S. The extraction procedure was similar to the protocol used for extracting all sulphides: 3 g of powdered sample were poured in a flask, heated at ≈ 100°C for 10 hours with 20 ml of pure water. No other reagent was added. Particular care was taken to ensure that all glassware was perfectly dry before experiment. Similarly to bulk S extraction, H2S was produced and converted to Ag2S.

Isotope analysis

The sulfur isotopic compositions were measured using a dual inlet Thermo Finnigan MAT 253 Mass Spectrometer at the Institut de Physique du Globe de Paris, France. M/z ratios 127, 128, 129 and 131 ratios were monitored simultaneously (respectively for 32 SF5 + , 33 SF5 + , 34 SF5 + , 36 SF5 + ). The δ 34 S values are calculated after calibration of our in-house SF6 tank, using the international standard IAEA-S1 recommended value of Robinson (1993). As this reference material is anchored to V-CDT, the δ 34 S values measured in this study are all given respect to V-CDT. There is no international calibration for neither Δ 33 S nor Δ 36 S and there are given with respect to our SF6 tank and were recalculated accordingly via the relations:

Δ 33 S = δ 33 S + 1000 x [(δ 34 S/1000 +1) 0.515 -1]

(1)

Δ 36 S = δ 36 S + 1000 x [(δ 34 S/1000 +1) 1.9 -1]

(2)

The quality of the measurements is estimated on the basis of the long term reproducibility of IAEA-S1 and IAEA-S2 reference materials (Table 1, Appendix A). Repeated analyses conducted during completion of this work gave, for IAEA-S1, δ 34 S = -0.378 ± 0.17 ‰, Δ 33 S = 0.117 ± 0.006 ‰ and Δ 36 S = -0.36 ± 0.28 ‰ (all 1σ, n=17) and δ 34 S = 22.01 ± 0.40 ‰, Δ 33 S = 0.03 ± 0.07 ‰ and Δ 36 S = -0.20 ± 0.3 ‰ (all 1σ, n=20). Those values are statistically indistinguishable from those given in [START_REF] Ono | Mass-dependent fractionation of quadruple stable sulfur isotope system as a new tracer of sulfur biogeochemical cycles[END_REF]), Johnson et al. (2008) and [START_REF] Labidi | Determination of multiple sulfur isotopes in glasses: A reappraisal of the MORB δ 34 S[END_REF]. CDT samples were also analyzed. They gave raw values of δ 34 S = -0.37 ± 0.2 ‰, Δ 33 S = -0.029 ± 0.004 ‰ and Δ 36 S = -0.129 ± 0.087 ‰ (all 1σ, n=9). To express our Δ 33 S and Δ 36 S results relative to V-CDT, V-CDT being assumed at zero, all results have been normalized to V-CDT using the above values and noted as Δ' 33 S and Δ' 36 S.

Each measurement session was preceded by a zero-enrichment. In addition, two standards (IAEA-S1, IAEA-S2 or CDT) samples were analyzed at each session, one at the beginning and one at the end to assess data quality.

RESULTS

Bulk sulfur

Our results are presented in Table 2 and Figure 1. The S isotopic composition of EH3, EH5

and EL3 are all within uncertainties of each others. These values are in good agreement with Gao and Thiemens (1993a), except for the EL6 and EL7 groups, for which our values (respectively δ 34 S = -0.66 ± 0.14 ‰ and δ 34 S = -0.64 ± 0.00 ‰) are distinctively lower compared with their values (δ 34 S = -0.24 ± 0.06 ‰, n = 3, σ = 1, Gao & Thiemens, 1993a).

Aubrites (Aubrite Main Group and Shallowater) show a mean value of δ 34 S = -0.43 ± 0.53 ‰ Δ' 33 S = 0.006 ± 0.037 ‰ and Δ' 36 S = 0.041 ± 0.237 ‰. Shallowater is a particular aubrite that is thought to come from a distinct parent body (Keil 1989[START_REF] Keil | Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies[END_REF]. As Shallowater (δ 34 S = -0.46 ‰) does not show any distinct isotopic composition in sulfur compared with other aubrites (δ 34 S = -0.43 ± 0.56 ‰, without Shallowater), we will not make any further distinction between the main group and Shallowater and regroup all of them in one "aubrites" entity. This merge is only made for purpose of clarity and does not imply in any way that Shallowater and the Main Group might originate from the same parent body based on S isotopic compositions.

Most of aubrites data overlap with the composition measured in enstatite chondrites, yet with several samples displaying more extreme values, between two poles, one positive (δ 34 S = +0.154 ‰ measured in Aubres) and one negative (δ 34 S = -1.350‰ as measured in Bishopville). Interestingly, Bishopville displays a significant difference in isotope composition between the two chunks (i.e. two distinct samples from two museums) that were analyzed from this meteorite (δ 34 S = -1.350‰ vs. δ 34 S = +0.215‰). This difference of 1.566 ‰ is way beyond the overall uncertainty of our analytical protocol, and must represent a sample heterogeneity. This heterogeneity is also noticeable in the different concentrations of sulfur between those two chunks, with an S content of about 1.9 wt% and 0.1 wt% for the 34 Sdepleted and -enriched samples respectively.

Cumberland Falls is a particular aubrite as it contains both clasts of aubritic nature and clasts from ordinary chondrite material that is thought to come from an impactor to the aubrite parent body. First analyses on undiscriminated powder from the meteorite gave a bulk composition of δ 34 S = -0.517 ± 0.06 ‰. Subsequent analyses on specifically selected aubritic and OC clasts showed an aubrite composition much more negative, δ 34 S = -1.903 ‰, while the OC clast showed a δ 34 S of 0.007 ‰, in perfect agreement with an ordinary chondrite signature (Gao & Thiemens 1993a) and confirming that aubrites are also heterogeneous in S isotopes.

No obvious MIF in 33 S or 36 S is observed in the bulk fraction analyses (Figure 2), neither in enstatite chondrites nor aubrites, mean values of Δ' 33 S and Δ' 36 S for each group being very close to zero. There is no distinctive trend in the Δ' 33 S or Δ' 36 S individual analyses, though a slight dispersion of the values beyond the standard deviation can be noted.

Water soluble fraction

Twelve large samples (4 EH and 8 aubrites) were specifically analyzed to access the S isotope composition of oldhamite (Table 3, Figure 3). Nine of them released enough sulfur to allow for analysis of S isotopes, while three (all aubrites) did not release any significant amount of sulfur. The sulfur isotopic composition of the water soluble fraction is distinctively different from the bulk S of enstatite meteorites, showing large variations between samples (with a δ 34 S from 0.66 ‰ to 10.95 ‰) and an enrichment in all three heavy isotopes compared to bulk S compositions, with averages δ 34 S = 3.62 ± 3.02 ‰, Δ' 33 S = -0.024 ± 0.027 ‰ and Δ' 36 S = 0.629 ± 0.724 ‰. Three samples (EH3 Indarch, and aubrites Norton County and Aubres)

show significant 36 S excess (respectively Δ' 36 S = 2.23 ‰, 1.19 ‰ and 0.91 ‰). Norton County is the only sample to show significant anomalies in both 36 S and 33 S, with a positive Δ' 36 S (+1.185 ‰) and a negative anomaly in Δ' 33 S (-0.085 ‰). This result contrasts with the datum of [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF] who measured a positive anomaly in Δ' 33 S of 0.161 ± 0.012 ‰ in oldhamite of Norton County and Δ' 36 S ≈ 0 ‰, suggesting that a given aubrite can also be isotopically heterogeneous in terms of 33 S isotopes, best illustrated by the water soluble fraction. To our knowledge, these isotope anomalies do not compare with other data in bulk meteorites [START_REF] Antonelli | Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets[END_REF]Hulston and Thode, 1965b).

DISCUSSION

Heterogeneity of the samples

Previous petrographic studies have shown that at a mm scale, samples can be very heterogeneous in their mineral composition (Mason 1965[START_REF] Keil | Mineralogical and chemical relationships among enstatite chondrites[END_REF][START_REF] Rubin | The Blithfield meteorite and the origin of sulfide-rich, metal-poor clasts and inclusions in brecciated enstatite chondrites[END_REF][START_REF] Brett | Enstatite chondrites and enstatite achondrites (aubrites) were not derived from the same parent body[END_REF]). This is supported by S isotopes and particularly for aubrites and EL6, which contain less sulfides than the other groups. In several cases, samples from the same chunks did not contain extractable sulfides. A misstep in the chemical extraction was unlikely since for samples for which enough material was available to perform replicates from the same chunk, as for pyrite tests, all the results were within experimental error. It is therefore more likely that these chunks did not contain any sulfide. Some of the samples that we had received as powders were possibly oxidized with the clear presence of rusty material.

Therefore the sulfides may had been oxidized to sulfates and were not extracted by our analytical method. In order to test this possibility we performed an extraction using Thode's method [START_REF] Thode | Sulphur isotope geochemistry[END_REF]) to extract sulfur from sulfates which did not yield anything either (see table 2). Therefore, it is more probable that the lack of sulfur was due to the heterogeneous nature of the original material (usually single chunks, or powder from a single chunk), which is expected given the brecciated nature of those samples, with clasts of mm to cm size. This idea is further supported by the fact that the two distinct chunks from Bishopville displayed contrasted isotope compositions.

Although the sulfur content can be heterogeneous, the isotopic composition remains fairly reproducible between different replicates of a same meteorite with a difference of less than 0.2 ‰ in δ 34 S, with the noticeable exceptions of Abee (EH4), which displays a variability of 0.377 ‰, and Bishopville (aubrite), showing a significant variation of 1.566 ‰ in δ 34 S.

Mass independent isotopic fractionation in the water soluble fraction

Significant MIF are observed in the water soluble fractions (Figure 4) of the analyzed samples showing a clear positive Δ' 36 S up to 2.23 ‰ for Indarch (with a corresponding Δ' 33 S = 0.006 ± 0.01 ‰), and a slightly negative Δ' 33 S of -0.085 ‰ in Norton County (with a Δ' 36 S = 1.185 ± 0.1 ‰). This contrast with the bulk sulfur fraction of EL, EH and aubrites, where very restricted MIF occurs with -0.009 ‰ < Δ' 33 S < +0.021 ‰ and -0.160 ‰ < Δ' 36 S < +0.319 ‰.

Oldhamite is a rare mineral only observed naturally in enstatite meteorites (chondrites and achondrites). It has never been observed on terrestrial samples, nor in other meteorite groups. [START_REF] Larimer | An experimental investigation of oldhamite, CaS; and the petrologic significance of oldhamite in meteorites[END_REF] showed that this peculiarity of enstatite meteorites is probably due to a highly-reduced environment of formation, with a low oxygen fugacity (log pO2 = 8.58 -25.35/T) associated with a high C/O ratio (≈ 0.9).

If these anomalies were imputable to experimental errors, as bulk and water soluble samples were analyzed in no particular order, they would likely appear in both S fractions (bulk and water soluble) of aubrites and enstatite chondrites. However, MIF is observed only among water soluble fractions. Moreover, the samples showing MIF were not analyzed during the same sessions, therefore, it is rather unlikely that they could result from experimental errors. This MIF signal is thus real, and specific to the water soluble fraction.

There are three typical explanations to generate MIF in meteorites: (1) cosmic ray spallation, including the production of cosmogenic nuclides (2) photochemically-induced gas phase chemical reactions and (3) stellar nucleosynthesis [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF], Chakraborky et al. 2013[START_REF] Antonelli | Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets[END_REF].

Spallation reactions leads to nuclides produced from interactions between highly energetic particles (cosmic rays in the case of Cosmic Ray Spallation, or CRS) and a target nuclei. CRS producing excess in S isotopes have only been studied in iron meteorites, where the target element -Fe -is the most abundant and the irradiation ages are the longest (Hulston & Thode 1965a, Hulston & Thode 1965b[START_REF] Gao | Systematic study of sulfur isotopic composition in iron meteorites and the occurrence of excess 33 S and 36 S. Geochim[END_REF]. In the absence of spallation studies on enstatite meteorites, iron meteorites remain the closest analogues and a comparison with iron meteorites is supported by the fact that EH and EL are the richest meteorites in iron after iron meteorites. In iron meteorites, spallation reactions is associated with a specific ratio Δ 36 S/Δ 33 S ≈ 8, which does not match favorably our results in enstatite meteorites (Figure 4), making spallation an unlikely explanation for the observed MIF. In particular, spallation would only create positive Δ 33 S and cannot account for our slightly negative Δ 33 S observed in Norton County.

Ruling out cosmic ray exposure and stellar nucleosynthesis as the origin of this excess in 33 S, [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF] concluded that mass-independent induced gas phase chemical reactions in the solar nebula was more likely to explain positive Δ 33 S up to 0.16 ‰ in Norton County.

Though our results are distinct in sign and magnitude we confirm that oldhamite, or at least, the water soluble fraction, is a carrier of MIF. The contrast of 0.25 ‰ in Δ 33 S between [START_REF] Rai | Photochemical mass-independent sulfur isotopes in achondritic meteorites[END_REF] and this study could be the illustration of significant heterogeneity in the Norton County meteorite.

On Earth, photochemistry reactions between UV on S-atmospheric species, such as SO2, leads to the production of MIF (Farquhar et al. 2000a[START_REF] Farquhar | Observation of wavelength-sensitive mass-independent sulfur isotope effects during SO2 photolysis: Implications for the early atmosphere[END_REF]. This is a well-accepted origin for terrestrial MIF recorded in Archean sulfides and sulfates as well as present-day sulfate aerosols in Antarctic ice cores [START_REF] Baroni | Mass-Independent Sulfur Isotopic Compositions in Stratospheric Volcanic Eruptions[END_REF][START_REF] Baroni | Anomalous sulfur isotope compositions of volcanic sulfate over the last millennium in Antarctic ice cores[END_REF]. One of the solar nebula prominent species in gas phase in reducing environment nebula is H2S. The specific isotope fractionations associated with photodissociation of H2S are still based on a very limited set of experiments at specific wavelengths. Experiments using a wavelength of ~220 nm show a positive Δ 36 S/Δ 33 S ratio of ≈ +1.7 (Farquhar et al. 2000b) while [START_REF] Chakraborty | Sulfur isotopic fractionation in vacuum UV photodissociation of hydrogen sulfide and its potential relevance to meteorite analysis[END_REF] showed that using a Lyman-α radiation (121.6 nm), that was suggested to be more representative of a T-Tauri sun, the Δ 36 S/Δ 33 S ratio becomes negative with a value of ≈ -3. S isotope anomalies associated with nucleosynthetic sources were recently reviewed by [START_REF] Antonelli | Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets[END_REF]. [START_REF] Clayton | On presolar meteoritic sulphides[END_REF] predicted an enrichment in 36 S while enrichment in 32 S compared to the three other S isotopes was predicted by Farquhar et al. (2000), with a slope of 1 in δ 33 S vs. δ 34 S and δ 36 S vs. δ 34 S diagrams, thus leading to a constant ratio of Δ 36 S/Δ 33 S ≈ -1.9. This was later confirmed by [START_REF] Hoppe | Sulfur Molecule Chemistry in Supernova Ejecta Recorded by Silicon Carbide Stardust[END_REF], though 36 S was not measured. Presolar SiC grains have indeed shown depletion in 33 S resulting in a Δ 33 S as low as -200 ‰. Those values are thought to be inherited from S formed in the Si/S zone of SNII Supernovae [START_REF] Hoppe | Sulfur Molecule Chemistry in Supernova Ejecta Recorded by Silicon Carbide Stardust[END_REF]. Nucleosynthetic processes in SNII supernovae could also produce enrichments in 36 S [START_REF] Woosley | Nucleosynthesis and remnants in massive stars of solar metallicity[END_REF], but those would be observed in the He/C zone and are thought to be associated with an enrichment in 33 S, resulting in positive Δ 33 S and Δ 36 S. None of these match our data, neither the bulk fraction (that shows no significant MIF, see Figure 2), nor in the water soluble fraction (Figure 4). (2014) being, therefore, consistent with such a process. However, the more restricted ranges in both ∆ 33 S and ∆ 36 S does not support the possibility of photochemistry-related isotope effect in our data. None of the above hypotheses gives a trend that matches the observed MIF in the water soluble fraction of the enstatite meteorite (Figure 4), and are thus unlikely explanation for our set of data.

Alternatively, the excess of 36 S could be inherited from another water soluble phase that would contaminate the water soluble fraction during chemical extraction of the oldhamite. If a phase carrying an excess of 36 S were to contaminate the oldhamite extract, then this excess could be misinterpreted as coming from the oldhamite itself. A possible candidate of such contamination is lawrencite (FeCl2). Indeed, lawrencite is water soluble and large excesses (> 200 ‰) of Δ 36 S have been measured and have been interpreted as the result of the decay of 36 Cl → 36 S (½ life ≈ 301,000 ± 2,000 years) [START_REF] Lin | Short-lived chlorine-36 in a Ca-and Al-rich inclusion from the Ningqiang carbonaceous chondrite[END_REF][START_REF] Jacobsen | Formation of the short-lived radionuclide 36 Cl in the protoplanetary disk during late-stage irradiation of a volatile-rich reservoir[END_REF]).

36 S is the rarest stable isotope of sulfur (~ 0.017%) and, as such, is the most sensitive to secondary isotope production. 36 Cl (½ life ≈ 301,000 ± 2,000 years) decays in both 36 Ar and 36 S (~ 99 and 1% respectively via 35 Cl(n, g) 36 Cl  36 Ar, 36 S) and given the bearing of noble gas geochemistry to date exposure ages, 36 Cl-production has therefore been widely studied, and is known to occur from several elements most primarily Fe, Ti, Ca and Cl (e.g. Leya et al., 2000aLeya et al., , 2000b Lawrencite is found in enstatite meteorites, for example it was described as an accessory mineral in the EL3 fragment of the polymict meteorite Almahata Sitta [START_REF] Lin | Earliest solid condensates consisting of the assemblage oldhamite, sinoite, graphite and excess 36 S in lawrencite from Almahata Sitta MS-17 EL3 Chondrite Fragment, Workshop on Formation of the First Solids in the Solar System[END_REF][START_REF] Feng | Excess 36 S in Lawrencite and Nitrogen Isotopic Compositions of Sinoite from Almahata Sitta MS-17 EL3 Chondrite Fragment[END_REF]) and many other aubrites and chondrites (e.g. [START_REF] Lundberg | Search for isotopic anomalies in oldhamite (CaS) from unequilibrated (E3) enstatite chondrites[END_REF]. If produced by 36 Cl-decay produced from 35 Cl, ∆ 36 S anomalies should be coupled with enrichment in both 36 Ar and 38 Ar, the latter being produced from 37 Cl(n, g) 38 Cl  38 Ar. Excesses of 36 Ar have been observed in several enstatite chondrites [START_REF] Okazaki | Noble gases in enstatite chondrites released by stepped crushing and heating[END_REF]) and aubrites (Miura et al. 2006). Establishing relationships between 36 Ar and 38 Ar budgets remain however difficult to address. The respective contribution of initial 'trapped' and produced 'cosmogenic' Ar are notably hard to calculate and is further complicated by the sensitivity of argon isotopes to terrestrial weathering [START_REF] Patzer | Noble gases in enstatite chondrites I: Exposure ages, pairing, and weathering effects[END_REF]. However, we did not identify any relationship between ∆ 36 S and exposure age (see Table 2). Although the lack of relationship may be taken as an argument against ∆ 36 S anomalies resulting from 36 Cl-decay, it is worth noting that exposure age of aubrites (i.e. 2 of our 3 samples yielding non-zero ∆ 36 S) may be biased, most data being obtained on brecciated samples [START_REF] Wieler | Cosmic-ray-produced noble gases in meteorites, Noble Gases in Geochemistry and Cosmochemistry[END_REF]Eugster 2003, p. 11).

Yet lawrencite (FeCl2) is a water soluble mineral and it is a likely to react and released its sulfur during the extraction of the water soluble fraction and, we suggest, is a possible candidate that should deserve future investigations. The 36 S excess measured in the water soluble fraction does not exceed 2 ‰. Assuming that this anomaly is entirely produced by the excess of 36 S from lawrencite and that this original excess is of ≥200 ‰, mass balance shows that less than 3 % of the 36 S from the water soluble fraction would come from the contribution of lawrencite, which in turn represents ≈ 0.1 % of the total S in the samples.

It is also possible that the excess of ∆ 36 S measured in the water soluble fraction originates from reactions with calcium, about half being likely contained in oldhamite. Few studies were devoted to the specific analysis of oldhamite; so far, no significant isotope anomaly has been recognized for Ca or S-isotopes (e.g. [START_REF] Lundberg | Search for isotopic anomalies in oldhamite (CaS) from unequilibrated (E3) enstatite chondrites[END_REF]. The errors on Smeasurements (typically 2-4‰) were however too large compared with the scale of ∆ 36 S anomalies we report. Therefore, we cannot exclude that the oldhamite is not the main carrier of ∆ 36 S-anomalies and future work on oldhamite could clarify this issue. Similarly, such investigations could help understanding the origin of the very positive δ 34 S-values, up to +11‰, measured in the water-soluble fraction.

The high reactivity of oldhamite and lawrencite with water could explain why it is only observed in highly reduced meteorites such as enstatite chondrites and achondrites, as the slightest contact with water (aqueous alteration, weathering, sample preparation) in C and O chondrites is likely to dissolve this mineral phase and mix it with the other sulfide/sulfate pool [START_REF] Larimer | An experimental investigation of oldhamite, CaS; and the petrologic significance of oldhamite in meteorites[END_REF]). Moreover, if the 36 S excess results from the decay of 36 Cl, it will have no effect on the bulk S isotopic compositions of the samples, which is consistent with the lack of correlation between Δ' 33 S and Δ' 36 S.

Parent Bodies

Our data show that it is not possible to discriminate EH3, EH5 and EL3 from their isotopic composition of sulfur. Enstatite chondrites formed in an extremely reduced environment, with a fO2 as low as 10 -21 atm (800°C), significantly different from the environment of formation of ordinary and carbonaceous chondrites, that show a fO2 respectively two and three order of magnitude higher (Brett & Sato, 1983). It is possible that it is these common and peculiar conditions of formations that led to similar isotopic compositions for EL and EH parent bodies, whatever EH and EL derive or not from the same parent body. Based upon the chemical compositions of enstatite chondrites, [START_REF] Kallemeyn | Compositions of enstatite (EH3, EH4,5 and EL6) chondrites: Implications regarding their formation[END_REF] suggested that the innermost region of the solar nebula, where enstatite meteorites most probably formed, had to be heterogeneous. Gao and Thiemens (1993a) argued against this idea, based on the evidence that EH and EL had distinct parent bodies, and yet similar S and O isotopic composition. Therefore the inner region of the nebula had to be isotopically homogeneous. However, the recent discovery of a small but significant difference between EL (Δ 17 O = -0.041 ± 0.026 ‰) and EH (Δ 17 O = -0.066 ± 0.027 ‰) would rather favor a slightly heterogeneous nebula [START_REF] Herwartz | Identification of the giant impactor Theia in lunar rocks[END_REF] However, EL6 are enriched in light S isotopes, and not heavy S isotopes. Kinetically driven evaporation would enrich the residue in heavier S isotopes (e.g. Davis and Richter 2003), so cannot explain the depletion in 34 S in EL of the highest metamorphic degree. One alternative explanation could be an oxidation occurring on the EL6 parent body. [START_REF] Mcewing | Sulphur Isotope Ratios in the Canyon Diablo Metallic Spheroids[END_REF] showed that oxidation of FeS sulfides caused enrichment in heavy S isotopes of the residue.

Being the most reduced bodies, an oxidation of enstatite chondrites would lead to marked petrographic features between EL6 and other enstatite meteorites, which is however not the case, making oxidation of EL6 an unlikely explanation. Oldhamite (which can be 34 S enriched)

being one of the most refractory minerals, its preferential evaporation is also unlikely.

REE studies [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF] and Fe isotopic compositions [START_REF] Wang | The iron isotope composition of enstatite meteorites: Implications for their origin and the metal/sulfide Fe isotopic fractionation factor[END_REF]) have also shown a unique behaviour in EL6 compared to other enstatite meteorites. [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF] reported that the EL6 are depleted in siderophile and chalcophile REE and that lithophile REE are more fractionated in EL6 than in other chondrites. For instance, in EL6, the ratio La/Yb = 0.79 against 1.05 for other enstatite chondrites [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF]). The The petrographic grades determined for EH meteorites range from EH3 to EH5. Though EH6 do exist [START_REF] Rubin | Shock effects in "EH6" enstatite chondrites and implications for collisional heating of the EH and EL parent asteroids[END_REF], very few have been studied. The EL group, on the other hand, shows a petrographic grade ranking up to EL6, and even EL7 for few samples. Happy

Canyon is officially classified by the Meteoritical Bulletin Database as EL6/7 and Ilafegh 009 is classified as EL7. The petrographic grade of type 7 designates chondrites that have been metamorphised nearly to the point of melting. Though this term is not widely accepted, it undoubtedly indicates the highest degree of metamorphism possible for an undifferentiated body.

Thus, it is possible that the EL parent body underwent a stronger metamorphism than the EH parent body, and that this metamorphism has affected the S isotopic composition of metamorphosed material of the EL parent body while not impacting the isotopic composition of the EH parent body. Other chondritic groups do not evidence a similar difference between petrographic grades, but no study reports a complete set of petrographic grades in a particular group of meteorites and there are no high metamorphic grades in carbonaceous chondrites. However, Gao and Thiemens (1993a) measured the sulfur isotopic composition of several ordinary chondrites, including the L3 ALHA 77216 and the LL6 ALHA 83071 and no significant difference were observed compared with other OC meteorites of lower metamorphic grade.

All the compositional differences noted in EL6 compared to others enstatite meteorites can be explained by an impact-induced high metamorphism on a unique EL parent body, creating locally a volatilization of Zn [START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF], a fractionation and depletion in REE [START_REF] Rubin | Shock effects in "EH6" enstatite chondrites and implications for collisional heating of the EH and EL parent asteroids[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF], and the large brecciation, causing heterogeneity of the Fe isotopic composition [START_REF] Wang | The iron isotope composition of enstatite meteorites: Implications for their origin and the metal/sulfide Fe isotopic fractionation factor[END_REF] as well as the loss of oldhamite that produced the light isotopic composition in S (this study).

Mass Dependent Isotopic Fractionation and loss of Oldhamite

The variable δ 34 S observed in the water soluble fraction (from 0.7 ‰ up to +10.95 ‰), is distinctively different from the bulk isotopic composition that is homogeneous and slightly and consistently negative in all enstatite meteorites. There are two ways to explain the oldhamite 34 S isotopic compositions. These positive signatures are either pristine, in which case it testifies of a different S reservoir for oldhamite than the other S-bearing minerals in the enstatite meteorites, or it has been isotopically modified and reflects an alteration process that affected only the (soluble) oldhamite. In the case of a pristine S isotopic composition, oldhamite would be the testimony of the existence of yet unknown reservoir, with the Δ 33 S remaining unaffected by any of the MIF-inducing processes highlighted before (spallation, UV photolysis, nucleosynthetic sources) with the possible exception of the negative Δ 33 S in Norton County.

Evaporation of CaS would lead to positive δ 34 S of residual CaS and, according to mass conservation effects (Farquhar et al., 2007) would also lead to significant but limited MIF: modelling was made using fractionation factors scaling to the square root of the mass of the evaporated species (Davies et al., 1990;Young et al., 2002) and shows that the maximum ∆ 33 S and ∆ 36 S would be -0.04 and 0.26‰ respectively for a residual δ 34 S of 10 ‰. Therefore, evaporation cannot be the main process responsible for ∆ 36 S anomalies up to +2.2‰, even if we cannot rule out that it might have contributed, among other processes, to the observed isotope variability of oldhamite (or soluble fraction).

Alternatively, oldhamite is a mineral that has an extraordinary high melting temperature of about 2525°C as a pure substance [START_REF] Mccoy | Partial melting of the Indarch (EH4) meteorite: A textural, chemical, and phase relations view of melting and melt migration[END_REF]) but can also melts at much lower temperatures in conjunction with other phases, in particular, low fO2 CaO-MgO-SiO2-CaS systems [START_REF] Rudneva | The effect of calcium sulfide on the phase composition of slags in the system CaO-MgO-SiO2[END_REF] and enstatite-chondrite melts (Fogel et al. 1996). Fusion experiments on Indarch have shown that at 1000°C, all sulfides and metal phases were melted [START_REF] Mccoy | Partial melting of the Indarch (EH4) meteorite: A textural, chemical, and phase relations view of melting and melt migration[END_REF]. This supports the idea that oldhamite should be lost through metamorphism on the EL parent body, though the occurrence of oldhamite in aubrites seems inconsistent with such an assumption.

It seems thus likely that a kinetic-driven alteration process could affect its S isotopic composition, leading to high 34 S residual compositions of the oldhamite. Figure 5 shows that apart from one anomalously CaS-rich sample (Indarch), a correlation seems to exist between δ 34 S of the oldhamite and its proportion in sulfides. This suggests that the loss of CaS induced a concentration of heavy isotopes and thus higher δ 34 S in the oldhamite residue, either during impact-induced melting events on the parent body or on the Earth's surface during subsequent storage.

At equilibrium, Cas is likely to be enriched by ~0.15 ‰ in 34 S, compared to FeS at T ≈ 1200°C

(as determined by extrapolating data from Ohmoto & Rye 1979; see Moretti et al. for review), while this value would rise to ≈ 2.5 ‰ at T ≈ 200°C. The loss of oldhamite is therefore consistent with a decrease of δ 34 S of EL6/7 but the most positive δ 34 S values are inconsistent with equilibrium processes and may highlight low temperature kinetic effects.

Previous studies [START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF] have suggested that loss of oldhamite to account for differences in REE content between EL3 and EL6. Lower REE concentrations in EL6 than in EL3 showed that REE are lost along with the oldhamite during impact-induced melting on the parent body and probably redistributed to other parts of the parent body. In every analyzed samples, the oldhamite fraction (0 to 20 % of total sulfur) shows a distinctively 34 S enriched isotopic composition, and this 34 S enrichment can be used to quantify this possibility. Because of the absence of EL3 fall and the most likely loss of oldhamite due to terrestrial alteration of EL3 finds and the loss of oldhamite observed in EL6

it is impossible to quantify the original amount and isotopic composition of oldhamite on the EL6 parent body. However, since EH3, EH5 and aubrites do not show any systematic S isotopic variations we suggest that, despite the large variations observed of composition observed between the different groups, that they are the best available proxy to estimate the isotopic composition of the EL parent body.

In order to estimate the loss of oldhamite between EL3 and EL6, we need to estimate the δ 34 S of the non-soluble (non-oldhamite) fraction. We make the hypothesis that the most 34 Sdepleted composition measured in an enstatite chondrite (in Pillistfer) corresponds to a 100% loss of oldhamite, and therefore, a non-soluble value: δ 34 Snon soluble = -1.17 ± 0.01 ‰.

Keeping in mind that Pillistfer may contain trace amounts of CaS, this value must be taken as an upper estimate of the non-soluble value. The mass balance for EL3 can be written:

δ 34 Stotal (EL3) = X . δ 34 Snon soluble + (1-X) . δ 34 SCaS (3)
with X the fraction of non-soluble sulfides and δ 34 Stotal (EL3) = -0.32 ± 0.15 ‰.

With Y the fraction of CaS lost, the mass balance for EL6 becomes:

δ 34 Stotal (EL6) = X . δ 34 Snon soluble + (1-X)(1-Y) . δ 34 SCaS (4)
Assuming an average difference between EL3 and EL6 of 0.3 ‰, the fraction of oldhamite lost (Y) can be deduced as a function of δ 34 SCaS and X. We calculated X and Y for a large range of δ 34 SCaS from 0 to 11 ‰. We found that Y is little sensitive to δ 34 SCaS with most values between 50 and 36 % for a range of δ 34 SCaS between 2.2 and 10.9 ‰ and corresponding X varying between 25 and 7 % respectively. This is slightly lower than Rubin et al. ( 2009)'s 60 % estimate of the loss of oldhamite, though remains consistent with the idea that the loss of oldhamite is linked to a difference in 34 S between EL3 and EL6.

Therefore it does not seem necessary to invoke a distinct parent body to explain the difference of composition of EL6 compared to EL3. An advanced metamorphism, leading to the loss of oldhamite, which melts at relatively low temperatures and migrates to other regions of the parent body, can easily explain the S isotopic composition of EL6, as well as differences in composition in REE. Metamorphism and loss of oldhamite would likely be induced by impacts on the EL parent body, causing local heating, which is also supported by the loss of heavy Zn by impact-induced volatilization [START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF].

The case of aubrites

Contrary to enstatite chondrites, aubrites display a very heterogeneous sulfur isotopic composition, showing the most extremes bulk values (-1.350‰ <δ 34 S< +0.154 ‰), including intermediate values overlapping the chondritic values measured in their undifferenciated counterparts. It is well accepted that the parent body of aubrites underwent local impactinduced melting events, leading, at least locally, to segregation of the molten metal and therefore partial differentiation. Segregation of metal and silicates causes a fractionation in S, enriching the silicate phase in the lighter isotopes and the metallic phase in the heavier isotopes [START_REF] Shahar | Sulfur isotopic fractionation during the differentiation of Mars[END_REF][START_REF] Labidi | Non-chondritic sulphur isotope composition of the terrestrial mantle[END_REF]. Aubrites are breccias, heavily rearranged rocks. It is therefore highly probable that the large variations in the S isotopic compositions reflect the various degrees of differentiations caused by the impact events and mixing with impact-related compounds. Even the largest samples (~1 cm 3 ) remained relatively small compared to the coarsed brecciation of aubrite meteorites of several cm wide, and therefore were not representative of the bulk value of the meteorite samples. In particular, this likely explains the variability observed in two distinct samples of Bishopville collected from two different museum collections. In addition to the previously mentioned depletion in heavy isotopes in relation of oldhamite loss, the most negative δ 34 S values represents the S composition of the most differentiated fraction of silicates. All together, these processes likely explain the large S isotope variability of aubrites compared with other enstatite meteorites.

Comparison with the Earth and other meteorite groups

Isotopic compositions of sulfur, and many other volatile and moderately-volatile elements (O, Zn…), in enstatite meteorites and Earth have emphasized a number of similarities which led to infer that they share a similar origin [START_REF] Clayton | Oxygen isotopic compositions of enstatite chondrites and aubrites[END_REF][START_REF] Javoy | The birth of the Earth's atmosphere: the behaviour and fate of its major elements[END_REF][START_REF] Javoy | The chemical composition of the Earth: Enstatite chondrite models[END_REF]).

The Earth is depleted in volatile elements compared to primitive CI chondritic and enstatite chondrites. It is possible that both the Earth and the Moon were essentially dry immediately after the giant impact at the origin of the Moon and that most volatiles accreted later, as a late veneer from e.g. carbonaceous chondrite or cometary-type material [START_REF] Javoy | The birth of the Earth's atmosphere: the behaviour and fate of its major elements[END_REF], Albarède et al. 2013, Paniello et al. 2013). For volatile and chalcophile/siderophile elements [START_REF] Allègre | The age of the Earth[END_REF][START_REF] Malavergne | New high-pressure and high-temperature metal/silicate partitioning of U and Pb: Implications for the cores of the Earth and Mars[END_REF][START_REF] Dasgupta | Carbon solubility in core melts in a shallow magma ocean environment and distribution of carbon between the Earth's core and the mantle[END_REF], Wood and Halliday 2010, Wood et al. 2010), core segregation adds an additional level of complexity.

In meteorites, sulfur is usually described as "chondritic" reflecting a limited isotope variability. The different meteorite groups and each class of meteorite greatly overlap, yet they have a rather narrow and distinct range of variation (Gao & Thiemens 1993a, Gao & Thiemens 1993b). Enstatite meteorites (average δ 34 S = -0.47 ± 0.44 ‰ (1σ)) are enriched in lighter isotopes compared to both ordinary chondrites (average δ 34 S = 0.04 ± 0.38 ‰ (1σ),

Gao & Thiemens 1993a) and carbonaceous chondrites. Carbonaceous chondrites display the largest range, exceeding all the measured compositions in other meteorites, with sulfides enriched in heavy isotopes (average δ 34 S = 2.02 ± 1.01 ‰ (1σ) Gao & Thiemens 1993b) compared to other meteoritic groups, while sulfates (average δ 34 S = -0.48 ± 1.01 ‰ (1σ) Gao & Thiemens 1993b) display particularly 34 S-depleted isotope compositions, most likely representing secondary products formed during aqueous alteration of the carbonaceous chondrite parent body (Gao and Thiemens 1993b) or appeared after their fall on Earth (Gounelle & Zolenski 2001). Early studies thus suggested that the original sulfur composition of the CC parent body was actually enriched in heavy isotopes, though this has been disproved more recently by [START_REF] Bullock | Sulfur isotopic composition of Fe-Ni sulfide grains in CI and CM carbonaceous chondrites[END_REF].

It so appears that the enstatite meteorites are the closest class of meteorites to Bulk Silicate Earth (BSE) in terms of S isotopes. [START_REF] Labidi | Non-chondritic sulphur isotope composition of the terrestrial mantle[END_REF] recently re-investigated the isotopic compositions of the convective mantle through the study of mid-ocean ridge basalts. Even though a certain variability has been observed in the isotopic composition of modern hotspots [START_REF] Cabral | Anomalous sulphur isotopes in plume lavas reveal deep mantle storage of Archaean crust[END_REF], implying a variability preserved in the convective mantle, the continental crust and sediments bear reasonably little sulfur to change significantly the global budget. The convective mantle is thus representative of the BSE being comprised between -1.80 ‰ and -1.05 ‰, with an average estimate of -1.28 ± 0.33 ‰. Assuming a chondritic Earth of -0.02 ± 0.06 ‰ in δ 34 S (Gao and Thiemens 1993b), and about 97% of terrestrial sulfur stored in the core [START_REF] Dreibus | Cosmochemical constraints on the sulfur content in the Earth's core[END_REF], the isotope composition of BSE is compatible with a core being enriched in 34 S compared with the residual mantle. They inferred a core-mantle isotopic fractionation factor for the 34 S/ 32 S ratio of αcore-mantle = 1.00130 [START_REF] Labidi | Non-chondritic sulphur isotope composition of the terrestrial mantle[END_REF]) compatible with the value experimentally determined by [START_REF] Shahar | Sulfur isotopic fractionation during the differentiation of Mars[END_REF]. This estimate is dependent on the amount of sulfur brought to Earth by late accretion events, such as the late veneer, occurring after the core segregation, which was neglected. If the little variability of "chondritic" S in meteorites (i.e. similar to OC and CC) rules out late veneer as the main contribution to the mantle, in the details, however, meteorites display a significant range of values.

The enrichment in light isotopes measured in EL6/7 as well as in aubrites, falls in the range of values reported by [START_REF] Labidi | Non-chondritic sulphur isotope composition of the terrestrial mantle[END_REF], suggesting that melting and differentiation could indeed lead to a silicate residual mantle depleted in 34 S. According to models [START_REF] Javoy | The chemical composition of the Earth: Enstatite chondrite models[END_REF], since Earth accreted from enstatite-like material, a δ 34 S-depleted starting material can be inferred. Our data also show that the most primitive EC give an average δ 34 S around -0.3 ‰, which is significantly different from the δ 34 S ≈ 0 ‰ otherwise used, which therefore changes the mass balance equation and requires re-estimating the amount of sulfur stored in the core. Assuming that the estimated isotopic fractionation factor remains the same (αcore-mantle = 1.00130), if the starting material is set at -0.3 ‰, mass balance calculation

shows that the amount of sulfur stored in the core drops to 75 %.

CONCLUSION

We measured the bulk S isotopic compositions of 33 enstatite meteorites (chondrites and aubrites) as well as the oldhamite fraction of 9 samples. As reported previously, enstatite chondrites have lighter isotopic compositions than other chondrites, displaying negative δ 34 S in all but one samples. However, in contrast with Gao and Thiemens (1993), we showed that EL6 have a distinct S isotopic composition, even more enriched in light isotopes than all other enstatite chondrite groups. This is explained by a loss in oldhamite, which is 34 Senriched. Aubrites show very variable S compositions, displaying the most extreme values. This is probably due to their brecciatic nature of impact-induced differentiated material and/or segregation of metal. MIF have been observed only in the oldhamite fraction and they are likely to be the product of an excess of 36 S produced by the decay of 36 Cl from FeCl2, which probably contaminated the oldhamite (water soluble) fraction during its chemical extraction. The sulfur isotopic composition measured in enstatite chondrites is distinct from the Bulk Silicate Earth, yet EL6/7 and aubrites are approaching its isotopic composition, making, in all cases, the enstatite meteorites the closest to the Earth composition, and reinforcing the idea that Earth was built from enstatite-like material.

  [START_REF] Antonelli | Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets[END_REF] measured the S isotopic compositions of iron meteorite troilites. They noted slight MIF, both positive and negative (-0.029 ‰ < Δ 33 S < +0.031 ‰, -0.34 ‰ < Δ 36 S < +0.28 ‰), showing a weak correlation of Δ 33 S/ Δ 36 S ≈ -7 that they interpret as being the produce of nebular photochemistry. Our data strongly overlap with those ofAntonelli et al.

  same goes for Sm/Yb (0.89 in EL6, 0.95 in EH), La/Sm (0.90 in EL6, 1.00 in EH) or Ca/Sc (0.86 in EL6, 0.97 in EH). They have also observed a depletion in the abundance of oldhamite in EL6, which is the main carrier of the REE along with plagioclase, that can account for the REE depletion and fractionation.[START_REF] Wang | The iron isotope composition of enstatite meteorites: Implications for their origin and the metal/sulfide Fe isotopic fractionation factor[END_REF] measured the isotopic compositions of Fe in all groups of enstatite meteorites and noted that, in contrast with the homogeneous compositions of EH (δ 56 Fe = 0.003 ± 0.042 ‰) and EL3 (δ 56 Fe = 0.030 ± 0.038 ‰), the EL6 displayed a large variability in their Fe isotopic composition, showing a δ 56 Fe varying from -0.180 ‰ to 0.181 ‰, which they explained as the consequences of the important brecciation underwent by EL6, mixing different proportions of mineral phases with distinct Fe isotopic compositions.

Figure 1 :

 1 Figure 1: Sulfur isotopic composition in the different groups of enstatite chondrites and aubrites. δ' 34 S = 1000xln(δ 34 S/1000+1), δ' 33 S = 1000xln(δ 33 S/1000+1). Δ'33S and Δ'36S are corrected values expressed vs. V-CDT

Figure 3 :

 3 Figure 3: Sulfur isotopic composition of the water soluble fraction in enstatite chondrites and aubrites. δ'34S = 1000xln(δ 34 S/1000+1), δ'33S = 1000xln(δ 33 S/1000+1)

Figure 5 :

 5 Figure 5: Relation between δ34'S composition of the water soluble fraction and the concentration in CaS in enstatite meteorites. δ'34S = 1000xln(δ 34 S/1000+1).

  Clayton et al. 1884 (b) Newton et al. 2000 (c ) this study (d)[START_REF] Patzer | Noble gases in enstatite chondrites I: Exposure ages, pairing, and weathering effects[END_REF] (f) Lorenzetti 2003

  Though this result supports the MIF observed in iron meteorites by[START_REF] Antonelli | Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets[END_REF], it does not match our own results. It remains possible that at a particular wavelength, or a distinct spectrum that might have existed during the early stage of the Solar Nebula, photochemistry created a MIF with a much stiffer slope (a Δ 36 S/Δ 33 S ratio of ≈ -12 would be necessary to match our data and account for the Δ' 33 S of -0.085 ‰ measured in Norton County) but this remains to be produced by experimental data. Though the Lyman-α is the strongest wavelength in the nebula, a contribution of other wavelengths, others sulfide species (HS, SiS, etc…), or systems with different composition (e.g. dust/gas ratio) might lead to a distinct MIF signal. Further studies are required to help clarify these issues.

  ).36 S production from36 Cl-decay is a viable explanation to account for the occurrence of positive ∆ 36 S in our sample set together with a lack of ∆ 33 S-anomaly. The only exception is, again, for Norton County. Other mechanisms such as spallation reactions on Fe (see above) would indeed lead to coupled ∆ 33 S and ∆ 36 S-anomalies, which are not observed in our dataset. The fact that positive ∆ 36 S are measured in two aubrites (i.e. with lower Fecontents than enstatite chondrites) is also consistent with such an observation.Radioactive 36 Cl is commonly suggested to result from either nucleosynthetic anomalies (e.g.Murty et al. 1997), neutron capture reactions of Cl-rich fluid/phase for example during T-Tauri phase of the sun[START_REF] Wasserburg | Extremely Na-and Cl-rich chondrule from the CV3 carbonaceous chondrite Allende[END_REF][START_REF] Jacobsen | Formation of the short-lived radionuclide 36 Cl in the protoplanetary disk during late-stage irradiation of a volatile-rich reservoir[END_REF][START_REF] Turner | Short lived 36Cl and its decay products 36Ar and 36S in the early solar system[END_REF]) and/or it subsequent production from primary and secondary particles on the parent body. Enstatite and aubrites have long exposure time (for review see[START_REF] Eugster | Cosmic-ray exposure ages of meteorites and lunar rocks and their significance[END_REF], consistent with e.g. Sm

and Gd isotopic studies (e.g.

[START_REF] Hidaka | Heterogeneous isotopic anomalies of Sm and Gd in the Norton County meteorite: evidence for irradiation from the active early sun[END_REF]

. Lawrencite (FeCl2) was found to bear large excesses of 36 S (∆ 36 S > 200 ‰) which were interpreted as the result of the decay of 36 Cl → 36 S

[START_REF] Lin | Short-lived chlorine-36 in a Ca-and Al-rich inclusion from the Ningqiang carbonaceous chondrite[END_REF][START_REF] Jacobsen | Formation of the short-lived radionuclide 36 Cl in the protoplanetary disk during late-stage irradiation of a volatile-rich reservoir[END_REF]

).

  . Thus, if an S isotope heterogeneity exists among EH and EL, it remains within our experimental error. However, our data showing that the EL6 (average δ 34 S = -0.66 ± 0.14 ‰ while average EH: δ 34 S = -0.25 ± 0.21 ‰) might have a distinct S composition, offers two possibilities. It can either indicate heterogeneities in the isotopic composition of sulfur in the inner area of the nebula, or the parent body processes

	that altered the original S composition of EL6/7. Yet, a difference between the Earth's
	mantle and ocean of 0.1 ‰ in Δ 17 O (Pack and Herwartz 2013) is comparatively larger than
	the difference between EL and EH. If a mechanism can produce up to 0.1 ‰ on Earth, then
	we enter a field where a difference of 0.3 ‰ in δ 34 S between EL and EH may not be
	significant enough to highlight a nebula heterogeneity, as processes on the parent body
	might alternatively lead to such variability.
	1997) whereas EL3
	show a Zn content of 213 ppm (Kong et al. 1997) and EH chondrites show a Zn content of
	290 ppm (Lodders and Fegley 1998), and were also enriched in light Zn isotopes, showing a
	δ 66 Zn = +4.88 ± 1.79 ‰ (1σ), compared to the other enstatite groups, both chondrites (δ 66 Zn
	= +0.25 ± 0.16 ‰ (1σ)) and aubrites (δ 66 Zn = +4.88 ± 1.79 ‰ (1σ)). Preferential loss of the
	heavier Zn isotopes would be caused by volatilization by impacts on the parent body of EL6.

Even though it is generally assumed that the EH and EL groups represent only two parent bodies, some recent studies have shown remarkable differences between EL6 and other enstatite chondrites

[START_REF] Rubin | Possible impact-induced refractory-lithophile fractionations in EL chondrites[END_REF][START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF][START_REF] Barrat | The lithophile trace elements in enstatite chondrites[END_REF][START_REF] Wang | The iron isotope composition of enstatite meteorites: Implications for their origin and the metal/sulfide Fe isotopic fractionation factor[END_REF]

). In agreement with our results, showing that the sulfur isotopic ratio of EL6 is distinct from all the other enstatite chondrites,

[START_REF] Moynier | Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes[END_REF]

have shown that the EL6 are depleted in Zn, with an estimated Zn concentration of 6 ppm

(Kong et al.

Table 1 :

 1 Averages of S isotopic analyses of standards Canyon Diablo Troilite (CDT), IAEA-S1 and IAEA-S2. δ 34 S is expressed vs. V-CDT, Δ 33 S and Δ 36 S are expressed vs. our SF6 tank.

	Phys. Rep. 442, 269-283.
	Zhang, J., Dauphas, N., Davis, A.M., Leya, I., Fedkin, A. (2012) The proto-Earth as a significant source
	of lunar material. Nat. Geosci. 5, 251-255.
	Zhang, Y., Benoit, P.H., Sears, D.W.G. (1995) The classification and complex thermal history of the
	enstatite chondrites. J. Geophys. Res. Planets 100, 9417-9438.
	LEGENDS

Δ' 33 S and Δ' 36 S are corrected values expressed vs. V-CDT. Standard deviations are given in 1σ.

Table 2 :

 2 Sulfur and oxygen isotopic compositions of bulk fraction of enstatite chondrites and aubrites. δ34S is expressed vs. V-CDT, Δ' 33 S and Δ' 36 S are corrected values expressed vs. V-CDT. Individual analysis precision are standard deviation of 0.01 ‰ on δ 33 S and δ 34 S and 0.1 ‰ on δ 36 S (1σ).

Table 3 :

 3 Sulfur isotopic composition of the water soluble fraction of enstatite chondrites and aubrites. δ 34 S is expressed vs. V-CDT, Δ'33S and Δ'36S are corrected values expressed

	vs. V-CDT. Individual analysis precision are standard deviation of 0.01 ‰ on δ33S and
	δ34S and 0.1 ‰ on δ36S (1σ).

  Δ 33 S and Δ 36 S are expressed vs. our SF6 tank. Δ' 33 S and Δ' 36 S are corrected values expressed vs. V-CDT. Individual analysis precision are of 0.01 ‰ on δ 33 S and δ 34 S and 0.1 ‰ on δ 36 S (1σ).

	Table 1
	Sample Sample	group	δ34S (‰) replica δ34S (‰) std dev. on replica (1σ)	Δ'33S (‰) Δ33S (‰) Δ36S (‰) Δ'33S (‰) Δ'36S (‰) std dev. on replica Δ'36S (‰) std dev. on replica [S] (wt%) std dev. on replica δ17O (‰) δ18O (‰) Δ17O (‰) (1σ) (1σ) (1σ)		Exposure age based on H3 composition (Ma)
	CDT (average) Sahara 97096 EH3	2	-0.377 -0.136	0.252	-0.029 -0.003 0.001	0.009	-0.129 0.042	4.4	0.000 0.51	0.000 2.77 5.45	-0.07	(a)	9.00	(d)
	Kota-Kota Alha 77295	std. dev.	EH3 EH3	2 3	0.210 -0.251 -0.312	0.166 0.289	0.005 0.000 0.002 -0.007 0.005	0.282 0.042	0.087 0.146 0.062	3.6 4.3	0.005 0.09 0.13	2.52 0.087 5.12 ----	-0.15 --	(a)	36.50	(d)
	Mil 07028		EH3	2	-0.400	0.096	0.007	0.001	-0.049	0.046	5.4	0.31	2.39	4.54	-0.04	(c)
	Gro 95517		EH3	5	-0.192	0.169	0.000	0.004	0.292	0.062	4.0	0.18	1.84	3.55	-0.02	(c)	35.10	(d)
	IAEA-1 (average) Qingzhen EH4 Abee EH4 Indarch EH4	1 6 3	-0.296 0.150 -0.672 -0.429	--0.289 0.140	0.088 0.000 --0.003 0.009 -0.002 0.006	0.116 0.143 -0.037	-0.486 --0.059 0.046	4.1 4.5 3.6	0.117 --0.86 0.81	2.83 3.47 -0.357 5.52 6.32 ----	-0.04 0.19 --	(b) (a)	1.90 7.70 8.20	(d) (d) (d)
	St. Mark's	std. dev.	EH5	5	0.168 -0.381	0.120	0.006 0.002 0.005	0.056	0.274 0.108	3.3	0.006 0.90	0.274 3.15 5.73	0.18	(a)	0.68	(d)
	Saint-Sauveur	EH5	4	-0.025	0.055	0.004	0.002	0.027	0.006	5.2	0.27	--	--	--
	LAP 02 225		EH5	3	-0.062	0.197	0.004	0.004	0.008	0.007	2.4	0.31	--	--	--
	IAEA-2 (average) Itqiy EH7-an	3	22.091 --	--	0.030 ----	--	-0.197 --	0.0	0.059 --	-0.068 ----	--
	MAC 88136 MAC 02837	std. dev.	EL3 EL3	3 3	0.395 -0.469 -0.165	0.097 0.090	0.075 0.007 0.003 0.004 0.004	0.009 0.059	0.298 0.037 0.015	2.2 2.8	0.075 0.06 0.23	2.01 0.298 4.07 1.96 3.84	-0.11 0.11	(b) (c)	1.20	(d)
	Hvittis		EL6	2	-0.455	0.089	0.000	0.016	-0.160	0.087	2.4	0.33	3.02	5.68	0.07	(a)	18.90	(d)
	IAEA-3 (average) Khairpur EL6 Eagle EL6	1 4	-32.510 -0.543 -0.642	--0.211	0.070 0.010 --0.008 0.006	0.071 -0.009	-0.501 --0.071	3.3 2.0	0.099 --0.60	3.17 -0.372 6.09 2.79 5.44	0.01 0.03	(b) (c)	29.40	(d)
	LON 94100 Pillistfer	std. dev.	EL6 EL6	1 1	0.063 -0.721 -1.017	----	0.007 -0.001 ---0.007 --	0.111 -0.139	0.260 ----	1.6 1.1	0.007 ----	--0.260 2.92 5.58 --	--0.02	(a)	32.60 4.10	(d) (d)
	Atlanta		EL6	1	-0.521	--	0.008	--	0.024	--	2.3	--	2.96	5.63	0.03	(a)	32.30	(d)
	Blithfield		EL6	1	-0.644	--	0.008	--	-0.035	--	4.9	--	2.82	5.29	0.07	(a)
	EET 92063		EL6	3	-0.655	0.262	-0.002	0.005	-0.024	0.037	1.8	0.14	3.06	5.84	0.03	(b)	35.30	(d)
	NWA 974		EL6	3	-0.801	0.173	0.008	0.003	0.269	0.041	2.0	0.57	3.32	5.94	0.22	(c)
	North West Forest	EL6	1	--	--	--	--	--	--	0.0	--	--	--	--
	Happy Canyon	EL7	1	-0.637		-0.009		0.070		0.2	0.07					26.80	(d)
	Ilafegh		EL7	3	-0.638	0.564	0.001	0.006	-0.085	0.015	0.5	0.22					3.80	(d)
	Shallowater		Aubrites	1	-0.465		0.008		0.319		2.8	--	2.99	5.79	-0.02	(b)	0.28	(f)
	Bishopville		Aubrites	1	-1.350	0.783	0.021	0.010	0.094	0.011	1.0	0.88	2.59	5.09	0.09	(b)	52.5	(f)
	Bishopville		Aubrites	1	0.215	--	0.000	--	0.117	--	--	--	--	--	--
	Norton County	Aubrites	1	-1.150	--	-0.008	--	0.023	--	0.6	0.13	2.57	4.98	-0.02	(b)	117.4	(f)
	Aubres		Aubrites	1	0.451	--	-0.003	--	-0.027	--	0.3	--	--	--	--
	Bustee		Aubrites	4	-0.189	0.080	0.008	0.001	-0.006	0.040	0.1	0.01	--	--	--		50.8	(f)
	Khor Temiki	Aubrites	1	-0.154	--	0.013	--	0.020	--	0.3	--	--	--	--		53.9	(f)
	Mayo Belwa	Aubrites	1	-0.404	--	0.007	--	-0.083	--	0.2	--	--	--	--		102.4	(f)
	Pena Blanca Spring	Aubrites	1	-0.766	--	0.008	--	-0.033	--	--	--	--	--	--		69.5	(f)
	Cumberland Falls	Aubrites	2	-0.517	0.068	0.011	0.003	-0.015	0.014	1.5	0.95	3.36	5.44	0.53	(b)
	Cumber. (Aubrite clast)	Aubrites	1	-1.903	--	0.017	--	0.078	--	0.1	--	--	--	--
	Cumber. (chondrite clast)	Aubrites	1	0.007	--	0.006	--	0.089	--	0.9

).

Appendix A: Replicate analyses of S isotopic analyses of standards Canyon Diablo Troilite (CDT), IAEA-S1 and IAEA-S2. δ 34 S is expressed vs. V-CDT,

Table 2

 2

	Sample	group	replica	δ34S (‰) Δ'33S (‰) Δ'36S (‰)	%CaS in S (wt%)
	Abee	EH3/4	1	2.477	-0.015	0.061	3.1
	Indarch	EH3/4	1	4.503	0.006	2.229	0.1
	St Mark's	EH5	1	0.666	-0.004	0.058	9.3
	St Sauveur	EH5	1	0.903	-0.003	0.178	4.8
	Aubres	Aubrites	1	2.219	-0.025	0.906	0.7
	Bustee	Aubrites	1	4.149	-0.037	0.065	61.9
	Mayo Belwa	Aubrites	1	5.370	-0.028	0.348	3.5
	Norton County	Aubrites	1	10.946	-0.085	1.185	1.2
	Pena Blanca Spring Aubrites	1	1.324	0.011	-0.048	--
	Cumberland Falls	Aubrites	1	--	--	--	0.0
	Bishopville	Aubrites	1	--	--	--	0.0
	Khor Temiki	Aubrites	1	--	--	--	0.0

ACKNOWLEDGEMENTS

The samples analyzed during the course of this study were kindly provided by Muséum National d'Histoire Naturelle (France), the Université Pierre et Marie Curie (France), The Smithsonian Institute (USA), The Natural History Museum of London (UK), Hawai'i Institute of Geophysics and Planetology (USA), and the NASA meteorite working group. US Antarctic meteorite samples are recovered by the Antarctic search for Meteorites (ANSMET) program which has been funded by NSF and NASA, and characterized and curated in the department of Mineral Sciences of the Smithsonian Institution and Astromaterials Curation Office at NASA Johnson Space Center. The authors thank INSU and CNES for the PNP grant. FM thanks the ERC for the Pristine Starting Grant, the Institut Universitaire de France and the ANR for a chaire de recherche IDEX SPC.