Lionel G Vacher
email: l.vacher@wustl.edu

Laurette Piani

Thomas Rigaudier

Dorian Thomassin

Guillaume Florin

Maxime Piralla

Yves Marrocchi

Hydrogen in chondrites: Influence of parent body alteration and atmospheric contamination on primordial components

Hydrogen occurs at the near percent level in the most hydrated chondrites (CI and CM) attesting to the presence of water in the asteroid-forming regions. Their H abundances and isotopic signatures are powerful proxies for deciphering the distribution of H in the protoplanetary disk and the origin of Earth's water. Here, we report H contents and isotopic compositions for a set of carbonaceous and ordinary chondrites, including previously analyzed and new samples analyzed after the powdered samples were degassed under vacuum at 120°C for 48 hours to remove adsorbed atmospheric water. By comparing our results to literature data, we reveal that the H budgets of both H-poor and H-rich carbonaceous chondrites are largely affected by atmospheric moisture, and that their precise quantification requires a specific pre-degassing procedure to correct for terrestrial contamination. Our results

show that indigenous H contents of CI carbonaceous chondrites usually considered the more hydrated meteorites are almost a factor of 2 lower than those previously reported, with uncontaminated D/H ratios differing significantly from that of Earth's oceans. Without pre-degassing, the H concentrations of H-poor samples (e.g., CVs chondrites) are also affected by terrestrial contamination. After correction for contamination, it appears that the amount of water in chondrites is not controlled by the matrix modal abundance, suggesting that the different chondritic parent bodies accreted variable amounts of water-ice grains. Our results also imply that (i) thermal metamorphism play an important role in determining the H content of both CV and ordinary chondrites but without affecting drastically their H isotopic composition since no clear D enrichment is observed with the increase of petrographic type and (ii) the D enrichment of ordinary chondrites does not result from the loss of isotopically light H 2 induced by metal oxidation but is rather linked to the persistence of a thermally resistant D-rich component.

Introduction

Hydrogen is the most abundant element in the solar system, but is present in only minor to trace amounts in asteroids and planetary bodies. Throughout the solar system and its history, H has occurred in various species, most commonly (i) H 2 in the gas phase, (ii) H 2 O molecules mostly as vapor and ice, (iii) OH -or H 2 O in silicate minerals, melts, and glasses, (iv) C-bonded H in organic compounds and (v) minor volatile species, such as NH 3 and H 2 S.

Today, water is present as ice, vapor, and/or liquid on Earth and other planets, dwarf planets, moons, and comets. The presence of OH -or H 2 O in the silicate minerals comprising primitive meteorites attests to the past existence of water on their asteroidal parent bodies and constitutes an invaluable record of the distribution and composition of water in the protoplanetary disk.

The H isotopic composition of water (expressed as D/H or per-mil deviations relative to Vienna standard mean ocean water, VSMOW, as D = [(D/H sample /D/H VSMOW ) -1] × 1000, where D/H VSMOW = 155.76 × 10 -6 ) in planetary objects is generally thought to increase with increasing heliocentric distance, from H 2 O that was in isotopic exchange with D-poor H 2 near the sun (D/H ≈ 21 × 10 -6 ; [START_REF] Geiss | Isotopic composition of H, He and Ne in the protosolar cloud[END_REF], to intermediate D/H ratios in inner solar system objects (e.g., Earth's ocean, D/H ≈ 156 × 10 -6 ), to D-enriched outer solar system objects such as comets (D/H up to 530 × 10 -6 in comet 67P/Churyumov-Gerasimenko; [START_REF] Altwegg | 67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio[END_REF]. Determining the precise abundances and isotopic compositions of H in meteorites-as representative samples of asteroids-is thus of fundamental importance for understanding the source(s) of water in the asteroid-forming regions [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF][START_REF] Piani | Micron-scale D/H heterogeneity in chondrite matrices: A signature of the pristine solar system water? Earth Planet[END_REF]Piani et al., , 2018;;[START_REF] Piani | Hydrogen isotopic composition of water in CV-type carbonaceous chondrites[END_REF] and potential radial mixing during the evolution of the protoplanetary disk [START_REF] Vacher | Inward radial mixing of interstellar Water ices in the solar protoplanetary disk[END_REF]Piani et al., 2018).

The origin of water on Earth and other telluric planets is also a long-standing question (Alexander, 2017;[START_REF] Mccubbin | Origin and abundances of H2O in the terrestrial planets, Moon, and asteroids[END_REF]. Although it is commonly assumed that the building blocks of the terrestrial planets derived from a cosmochemical reservoir best represented by enstatite chondrites, they accreted in a region where temperatures were too high for water and other volatiles to condense [START_REF] Albarede | Volatile accretion history of the terrestrial planets and dynamic implications[END_REF]. Therefore, these bodies are expected to be highly volatile-depleted, though they have tenuous atmospheres and water is largely present on Earth and Mars [START_REF] Taylor | The bulk composition of Mars[END_REF], and possibly in the Venusian and Mercurian atmospheres [START_REF] Smrekar | Constraints on mantle plumes on Venus: Implications for volatile history[END_REF]. For Earth, this paradox is generally bypassed by invoking the late accretion of 1-4 wt% of hydrated carbonaceous chondrites (i.e., CI-CM chondrites), which arrived at Earth due to the formation and subsequent migration of Jupiter [START_REF] Morbidelli | Source regions and timescales for the delivery of water to the Earth[END_REF][START_REF] Marty | The origins and concentrations of water, carbon, nitrogen and noble gases on Earth[END_REF][START_REF] Marty | Origins of volatile elements (H, C, N, noble gases) on Earth and Mars in light of recent results from the ROSETTA cometary mission[END_REF][START_REF] Raymond | Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion[END_REF]. Such a conclusion is highly dependent on our ability to precisely quantify the bulk H contents and D/H ratios of extraterrestrial materials. This point is not trivial since, despite being commonly measured, H is the most prone element to terrestrial contamination (except for noble gases; [START_REF] Protin | Irreversible adsorption of atmospheric helium on olivine: A lobster pot analogy[END_REF]. For instance, it was recently shown that Martian meteorites suffer rapid (<1 yr) terrestrial weathering and contamination that largely affect the water contents and H isotopic compositions of minerals exposed at their surface [START_REF] Stephant | Terrestrial exposure of a fresh Martian meteorite causes rapid changes in hydrogen isotopes and water concentrations[END_REF]. Moreover, water and volatile hydrocarbons (CH 2 and CH 3 ) quickly adsorb onto rock surfaces, raising potential H and C contamination issues during sample preparation [START_REF] Salisbury | Midinfrared (2.5-13.5/ m) Reflectance Spectra[END_REF]. This implies that the H budget estimated for a given meteorite is a complex mixture between indigenous hydrogen in minerals and organics and exogenous H due to terrestrial weathering and adsorption. Corrections for exogenous H could be achieved by performing (i) stepwise heating measurements to decipher between adsorbed, alteration, and indigenous water [START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF] or (ii) sample degassing under vacuum at low temperature (e.g., [START_REF] Vacher | Inward radial mixing of interstellar Water ices in the solar protoplanetary disk[END_REF]. Bulk H budget reconstructions from stepwise heating experiments are difficult due to the presence of different water-bearing minerals characterized by variable contamination susceptibilities that release adsorbed water at various temperatures. Furthermore, there is no consensus on a procedure to remove adsorbed water from both terrestrial and extraterrestrial materials, and different studies have employed various temperatures (70-350 °C) and durations (2-480 h) of heating under vacuum [START_REF] Savin | The oxygen and hydrogen isotope geochemistry of clay minerals[END_REF][START_REF] Girard | Unraveling climatic changes from intraprofile variation in oxygen and hydrogen isotopic composition of goethite and kaolinite in laterites: an integrated study from Yaou, French Guiana[END_REF][START_REF] Gong | TC/EA-MS online determination of hydrogen isotope composition and water concentration in eclogitic garnet[END_REF][START_REF] Lupker | Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)[END_REF].

Of note, a recent estimation of the bulk H contents and isotopic compositions of a large set of chondrites was performed without a pre-degassing protocol [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF], and therefore may have overestimated the H budget of primitive meteorites. In addition to terrestrial contamination, meteorites experienced parent-body alteration processes (hydrothermal alteration and thermal metamorphism; [START_REF] Brearley | The action of water[END_REF][START_REF] Huss | Thermal Metamorphism in Chondrites[END_REF][START_REF] Marrocchi | Origin and abundance of water in carbonaceous asteroids[END_REF] whose influence on their pre-accretion H characteristics remains unclear.

Here, to better understand the origin of hydrogen accreted by chondrites, we report the H concentrations and isotopic compositions of a large set of carbonaceous and ordinary chondrites. To test the influence of laboratory pre-degassing temperature, we selected chondrites that have been previously characterized (C2-ung. = Tagish Lake; CI = Orgueil and Alais; CY = Yamato 980115; King et al., 2019a;CM = Murchison, Mighei, and Murray;CV = Allende, Bali, Grosnaja, Kaba, and Vigarano;[START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF][START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. As CM chondrites represent 25% of all carbonaceous chondrite falls [START_REF] Gounelle | Hydrogen isotopic composition of water from fossil micrometeorites in howardites[END_REF], several new CMs have recently been described. We thus report the H concentrations and isotopic compositions of new CM falls (Aguas Zarcas, Maribo and Munkundpura; [START_REF] Haack | Maribo-A new CM fall from Denmark[END_REF][START_REF] Rudraswami | Chemical, isotopic and amino acid composition of Mukundpura CM2.0 (CM1) chondrite: Evidence of parent body aqueous alteration[END_REF] and finds (Lonewolf Nunataks (LON) 94101 and Jbilet Winselwan; [START_REF] Lindgren | Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: Evidence for aqueous alteration prior to complex mixing[END_REF]King et al., 2019b). In addition, several ordinary chondrites and a CK-type carbonaceous chondrite covering the entire range of thermal metamorphism [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF] were analyzed to test the influence of parent-body metamorphism on H characteristics (L3 = Grosvenor Mountains (GRO) 95502, CK4 = Karoonda, L4 = Saratov, LL/L4 = Bjurbole, H4 = Sainte Marguerite, and H6 = Kernouve). We use our results to discuss the nature of primordial components accreted by chondrites and the influence of post-accretion effects, either in asteroidal bodies or at Earth's surface.

Materials and method

Bulk measurements of H contents and isotope compositions

Hydrogen concentrations, [H], and isotopic compositions, D/H, of the different meteoritic samples were determined on-line using the Thermo Scientific EA IsoLink -deltaV IRMS System at CRPG laboratory (Nancy, France) according to the procedure developed by [START_REF] Lupker | Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)[END_REF]. First, meteoritic samples were crushed into powder in an agate mortar, weighed in tin capsules (CM, CI, CY and Tagish Lake: 1-3 mg; CV, CK, and OC: 4-10 mg), and the samples and capsules were loaded into a sample carrousel and degassed under vacuum at 120 °C for 48 h in a degassing canister [START_REF] Lupker | Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)[END_REF][START_REF] Gaudin | Mineralogical and δ18O-δD isotopic study of kaolinized micaschists at Penestin, Armorican Massif, France: New constraint in the kaolinization process[END_REF]Fig. 1A); degassing for less than 48 h was shown to result in increased variability of water contents and isotopic compositions due to remaining absorbed water [START_REF] Lupker | Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)[END_REF]. After dehydration, the degassing canister was opened in a dry, N 2flushed glove box and the sample carrousel was transferred into a sealed auto-sampler initially pre-flushed with He (Fig. 1B). The auto-sampler was then connected to the EA and pumped out during 20 min before opening it to the reduction column as a precautionary step to suppress any potential rehydration of the samples in the event of atmospheric contact between degassing and analysis.

The samples were combusted at 1450 °C (required temperature to ensure rapid sample reduction and to prevent any CH 3 formation) on a glassy carbon reaction tube filled with glassy carbon chips and itself placed into a ceramic liner to reduce hydroxyls (OH) released by the samples into H 2 according to the reaction: 2OH + C (unlimited in reactor)  2CO + H 2 (Fig. 1C). The produced gases were separated on a chromatographic column maintained at 60 °C and the extracted H 2 was introduced into the mass spectrometer through an open-split and its D/H isotopic composition was analyzed (Fig. 1D). The extracted H 2 was corrected for H 3 + contributions using in-house H 2 standard injections and [H] and D/H were determined by comparison with seven internal standards routinely included during the analyses: (i) phlogopite (Mica-Mg, 0.29 wt.% H, D/H = 143.8 × 10 -6 ), (ii) muscovite (MuscD65, 0.474 wt.% H, D/H = 142.6 × 10 -6 ), (iii) a fine-grained marine sediment from the Bay of Bengal (SO188, 0.489 wt.% H, D/H = 142.7 × 10 -6 ), and (iv) four basalts with different H concentrations (CYP78, 0.14 wt.% H; JB3-GSJ, 0.20 wt.% H; SR2-02, 0.27 wt.% H; and GMR-KS12, 0.42 wt.% H). Errors on hydrogen concentrations, calculated as twice the standard deviation divided by the average, increase with decreasing standard water content following the negative power law 2SD / [H] = 0.05 × [H] -0.43 , which was used to estimate the 2σ sample errors reported in Table 1. Hydrogen isotopic compositions are reported as D/H ratios or as δD values (‰) relative to VSMOW. The reproducibility of this method is better than 15% (2σ) for [H] and 0.5 × 10 -6 for D/H (or 5‰ for δD).

Bulk measurements of C and N concentration and isotopic compositions

Carbon and nitrogen concentrations ([C] and [N], respectively) and carbon isotopic compositions (δ 13 C, 13 C/ 12 C variations reported relative to Vienna Pee Dee Belemnite, VPDB, where 13 C/ 12 C VPDB = 0.01123720) of the different meteoritic samples were determined on-line using the Thermo Scientific EA IsoLink -deltaV IRMS System at the CRPG laboratory.

Samples were crushed into fine powder and wrapped in tin capsules (2-29 mg). The capsules were loaded in a specific auto-sampler connected to the EA and pumped out during 20 min before opening it to the oxidation column. Samples were then introduced into an oxidation reactor made of a quartz tube filled with chromium oxide, pure copper, and silvered cobalt oxide and heated at 1020 °C. A controlled pulse of oxygen causes the oxidation of tin capsules leading to an exothermic reaction that raises the sample temperature to about 1800°C. The produced gases (N 2 , CO 2 ) were separated on a chromatographic column maintained at 70 °C and the carbon isotopic composition of the extracted CO 2 was measured with a Thermo Scientific Delta V Advantage continuous flow IRMS. Carbon isotopic composition were determined by comparison with two internal and two international standards routinely included during the analysis: (i) BFSd (δ 13 C = -21.5‰), (ii) CRPG_M2 (δ 13 C = -24.98‰), (iii) NBS22 (δ 13 C = -30.03‰) and (iv) USGS24 (δ 13 C = -16.1‰). Values are quoted in the delta notation in ‰ relative to V-PDB and the reproducibility was better than 0.2‰. Four internal standards were used to calculate [N] and [C]: (i) BFSd (0.53 wt.% C), (ii) CRPG_M2 (0.408 wt.% C), (iii) Eurovector Synthetic Soil Mix #1 (0.216 wt.% N, 3.5 wt.% C) and (iv) Eurovector Synthetic Soil Mix #4 (0.048 wt.% N, 2.417 wt.% C). Errors (2σ) on [N] are estimated to be 10% and 30% for samples containing more and less than 0.08 wt.% N, respectively. For carbon analyses, 2σ errors are expected to be 2% for [C] and 2‰ for δ 13 C.

Results

Hydrogen characteristics of chondrites

Results from hydrogen extractions and associated D/H isotopic analyses are presented in Table 1 andFigure 2. For most samples (excluding C2-ung. Tagish Lake and CI Alais for their D/H variability), replicate aliquots of the same meteorite exhibit good reproducibility, with 2σ standard deviations less than 15% for [H] and 5‰ for δD.

Hydrogen abundances of CI, CY and CM chondrites vary widely, but exhibit comparable ranges, from 0.47 to 1.01 wt.% H (Fig. 2A). The lowest hydrogen contents were measured in CM Jbilet Winselwan, possibly due to dehydration during parent-body metamorphism (King et al., 2019b). CMs are depleted in deuterium compared to CIs (D/H CM = 131-170 × 10 -6 vs. D/H CI ≈ 177 × 10 -6 ) but show similar range of D/H values as the CY Antarctica Y-980115 (D/H CY = 139 × 10 -6 , Fig. 2B). The low hydrogen content of Y-980115 (0.71 wt.% H) relative to CI-CM chondrites and its D-poor isotopic composition might be might be a consequence of (i) thermal metamorphosed at temperature > 500°C (King et al., 2019a) and/or (ii) terrestrial weathering (e.g., Alexander et al., 2018a). The ungrouped C2 carbonaceous chondrite Tagish Lake exhibits a hydrogen content similar to the lowest value measured for CM chondrites (0.43 wt.% H), but this unique carbonaceous chondrite is the most D enriched (D/H = 225 × 10 -6 , Fig. 2A andB), consistent with previous measurements [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. CV chondrites (0.06-0.19 wt% H, Fig. 2A) contain lower hydrogen concentrations than CM and CI chondrites, whereas their hydrogen isotopic compositions are highly variable (D/H = 139-161 × 10 -6 , Table 1) over a range similar to that of CM chondrites (Fig. 2B). Ordinary chondrites and CK-type carbonaceous chondrites present the lowest hydrogen concentrations (≤0.03 wt.% H, excluding Grosvenor Mountains (GRO) 95502, an Antarctic find possibly affected by terrestrial weathering; Fig. 2A), and have relatively D-poor hydrogen isotopic compositions (D/H = 134-144 × 10 -6 , Fig. 2B).

Nitrogen and carbon characteristics of chondrites

Table 2 summarizes the carbon and nitrogen contents and carbon isotopic compositions of the analyzed chondrites. CI, CY and CM chondrites contain the highest N and C contents in this study, with 0.09-0.17 wt.% N and 1.54-3.04 wt.% C in CMs and 0.09-0.21 wt.% N and 3.06-3.35 wt.% C in CIs (Fig. 3). They both show comparable ranges of carbon isotopic compositions, with δ 13 C ranging from -16 to -13‰ and -14 to -4‰ for CIs and CMs, respectively. The nitrogen and carbon concentrations in Tagish Lake (0.11 wt.% N and 2.14 wt.% C) are comparable to those in CM chondrites, but with a more 13 C-enriched isotopic composition (δ 13 C ≈ +5‰). Compared with these Cand N-rich chondrites, CV, CK, and ordinary chondrites are depleted in N (≤0.03 wt.%) and C (≤1.42 wt.%), and have lower carbon isotopic compositions than hydrated chondrites, with δ 13 C ≈ -27 to -18‰.

Discussion

Effect of terrestrial contamination in carbonaceous chondrites

4.1.1 Influence of pre-degassing temperature on the total H budget Immediately after falling to Earth's surface, meteorites are exposed to terrestrial moisture and precipitation that could significantly affect their H characteristics, even in dry environments such as hot deserts [START_REF] Stephant | Terrestrial exposure of a fresh Martian meteorite causes rapid changes in hydrogen isotopes and water concentrations[END_REF]. Consequently, bulk meteorite H budgets are complex mixtures of indigenous hydrogen, terrestrial weathering, and adsorbed water hosted by different minerals/phases with variable thermal behaviors. Thermogravimetric analysis and derivate curves obtained in the range 25-1200 °C [START_REF] Garenne | The abundance and stability of "water" in type 1 and 2 carbonaceous chondrites (CI, CM and CR)[END_REF][START_REF] King | Modal mineralogy of CI and CI-like chondrites by X-ray diffraction[END_REF][START_REF] Gilmour | Water abundance in the Tagish Lake meteorite from TGA and IR spectroscopy: Evaluation of aqueous alteration[END_REF] suggest a complex thermal evolution of H-bearing phases with the following release temperatures: (i) 25-200 °C for absorbed H 2 O, (ii) 200-400 °C for water in hydroxides and H-bearing organic matter, (iii) 400-770 °C for OH -in phyllosilicates, and (iv) 770-900 °C for H 2 O in sulfates. Although suspected to occur to some degree at 200-400 °C, it has been proposed that adsorbed terrestrial water is mainly released from hydrated carbonaceous chondrites at 25-250 °C [START_REF] Boato | The isotopic composition of hydrogen and carbon in the carbonaceous chondrites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF][START_REF] Baker | The oxygen isotopic composition of water from Tagish Lake: Its relationship to low-temperature phases and to other carbonaceous chondrites[END_REF][START_REF] Garenne | The abundance and stability of "water" in type 1 and 2 carbonaceous chondrites (CI, CM and CR)[END_REF][START_REF] Gilmour | Water abundance in the Tagish Lake meteorite from TGA and IR spectroscopy: Evaluation of aqueous alteration[END_REF]. [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF][START_REF] Alexander | The classification of CM and CR chondrites using bulk H, C and N abundances and isotopic compositions[END_REF] reported H concentrations and isotopic compositions for a large set of carbonaceous chondrites that were stored in desiccators at room temperature for days to weeks prior to analyses. Their data define a positive correlation in a D/H vs. 1/H diagram (Fig. 4) that reveals the increasing contribution of H-bearing, D-rich, insoluble organic matter (IOM; [START_REF] Alexander | The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] to the total H budget, the largest contributions coming from phyllosilicates in hydrated chondrites. Our data define a similar positive trend, but with a statistically different slope (Fig. 4) that reveals the influence of the pre-degassing temperature on observed meteorite H features. Thereby, our bulk H measurements of samples also measured by [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] demonstrate that predegassed CM and CI chondrites contain ~10-30% and ~40% less H, respectively, than nondegassed samples (Fig. 4). Several reasons can be invoked to explain such important differences: (i) the significant loss of indigenous hydrogen induced by the pre-degassing protocol, leading to an underestimated H budget, (ii) sample heterogeneity, the effects of which are apparent due to the small amounts of material analyzed, and/or (iii) the intended removal of absorbed terrestrial water.

To test these different scenarios, we estimated the H isotopic composition of the hydrogen lost during pre-degassing at 120 °C for 48 h using the following mass balance equation:

(1)

where [H] [START_REF] Lécuyer | The hydrogen isotope composition of seawater and the global water cycle[END_REF][START_REF] Frankenberg | Dynamic Processes Governing Lower-Tropospheric HDO/H 2 O Ratios as Observed from Space and Ground[END_REF][START_REF] Clog | The hydrogen isotopic composition and water content of southern Pacific MORB: A reassessment of the D/H ratio of the depleted mantle reservoir[END_REF], but differ strongly from the (i) D-poor phyllosilicates that bear the signature of asteroidal water in CM and CI chondrites (D/H ~ 85-125 × 10 -6 ; [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]Piani et al., 2018[START_REF] Piani | Hydrogen isotopic composition of water in hydrated chondrites[END_REF] and (ii) D-rich organic matter (D/H ~ 265-310 × 10 -6 ; [START_REF] Alexander | The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter[END_REF]. Consequently, we interpret the differences in H concentrations obtained with and without the pre-degassing routine as mostly due to contamination of primitive meteorites by atmospheric moisture. This scenario cannot, however, explain the D/H ratio calculated of the H degassed from LON 94101, which display a significantly higher D/H value compared to the other common samples (~ 400 × 10 -6 ). By analogy with other CM chondrites, the removal of indigenous H during pre-degassing would result in a D-poor signature for [H] lost , at odds with our calculations. Alternatively, the preferential degassing of H from D-rich IOM or H-bearing organic compounds (i.e., small hydrocarbons or molecules found in the soluble part of the meteoritic organic matter) might explain such high D/H values and contributed to the H budget removed during our predegassing procedure. However, given that (i) the H isotopic compositions of [H] lost are D-poor compared to organic molecules in carbonaceous chondrites (Pizzarello et al., 1994;[START_REF] Brearley | The action of water[END_REF] Yamashita & Naraoka, 2014), (ii) stepwise pyrolysis performed by [START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF] on Murchison and Murray indicates that only few amount of carbon (~ 0.2 mol% of the total C) were lost compared to water below 200 °C (11.5 and 10.8 mol% of the total H, respectively), and (iii) the decomposition of IOM likely occurs at 200-500 °C [START_REF] Gilmour | Water abundance in the Tagish Lake meteorite from TGA and IR spectroscopy: Evaluation of aqueous alteration[END_REF][START_REF] Remusat | Molecular and isotopic behavior of insoluble organic matter of the Orgueil meteorite upon heating[END_REF], we concluded that the amount of indigenous organics volatile lost during pre-degassing is not significant and the D-rich compositions of the [H] lost by LON 94101 is rather a consequence of sample heterogeneity [START_REF] Lindgren | Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: Evidence for aqueous alteration prior to complex mixing[END_REF].

Quantification of terrestrial contamination in carbonaceous chondrites

To estimate the influence of pre-degassing, we compare hydrogen concentrations and isotopic compositions measured in different studies for CI Orgueil and CM Murchison as a function of pre-degassing temperature. Murchison shows ~30% less H after pre-degassing at 200 °C compared to measurements performed without pre-degassing (Fig. 5A-C).

Isotopically, this sample does not show a large change, with D/H value of ~150 × 10 -6 (Fig. 5C). In contrast, a sample of Orgueil pre-degassed at 120-350 °C shows (i) a H loss of up to ~40-80% and (ii) a D/H increase up to ~190 × 10 -6 relative to samples measured without predegassing (D/H ~ 150 × 10 -6 ; Figs. 5B-D). This disparity between CM and CI chondrites [START_REF] Busemann | Interstellar Chemistry Recorded in Organic Matter from Primitive Meteorites[END_REF][START_REF] Alexander | The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter[END_REF]Piani et al., 2018[START_REF] Piani | Hydrogen isotopic composition of water in hydrated chondrites[END_REF], with bulk H isotopic compositions (D/H CI ~ 177 × 10 -6 ) markedly higher than that of the contaminating water. Consequently, the effects of atmospheric moisture are more perceptible in CIs than in CMs.

To better quantify the influence of terrestrial contamination, we compared [H] lost (= [H] 25 °C -[H] 120 °C) for different chondrites as a function of the H concentration determined after pre-degassing at 120°C. We thusly obtained separate linear trends for CI, CM and CV carbonaceous chondrites, indicating that meteorites containing more H are more prone to contamination (Fig. 6). Interestingly, CM-and CI-type chondrites seem to define a single trend (r 2 = 0.70; MSWD = 1.5), suggesting that CIs would be more affected by H contamination than CMs (Fig. 6). The H concentrations of Tagish Lake are highly heterogeneous (H = 1.37 and 0.85 wt.%, from [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF]Alexander et al., 2012, respectively) and have been shown to depend strongly on the studied lithology (H = 0.74-0.94 wt.%; [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]; however, as we do not have the petrological details of the Tagish lake pieces measured in our study, we omit Tagish Lake from further discussion.

The difference in the amount of H loss between CI and CMs probably reflects secondary mineralogical diversity between these two groups of chondrites (Fig. 6). CI chondrites are mainly dominated by serpentine and saponite minerals, the latter being clay minerals with the capacity to absorb significant amounts of water into their inter-layers [START_REF] Tomeoka | Matrix mineralogy of the Orgueil CI carbonaceous chondrite[END_REF][START_REF] King | Modal mineralogy of CI and CI-like chondrites by X-ray diffraction[END_REF]. Thus, it is likely that CI chondrites contains indigenous inter-layer water that could be removed alongside with terrestrial water during pre-degassing, leading to an underestimation of the H budget in CI chondrites. Nevertheless, it appears that the high abundance of inter-layer water in Orgueil is probably related to its long residence time on Earth (since 1864) and it is likely that this meteorite was devoid of inter-layer water prior to its arrival on Earth [START_REF] Baker | The oxygen isotopic composition of water from Tagish Lake: Its relationship to low-temperature phases and to other carbonaceous chondrites[END_REF]. In addition, stepwise heating performed on Orgueil demonstrated that water released at temperature lower than 200 °C is characterized by terrestrial-like values (i.e.,  17 O = 0 ‰ and D/H = 153 × 10 -6 ), supporting that only minor indigenous water was present in the inter-layers of Orgueil [START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Baker | The oxygen isotopic composition of water from Tagish Lake: Its relationship to low-temperature phases and to other carbonaceous chondrites[END_REF]. In contrast, CM chondrites are almost saponite-free, and are instead dominated by Fe-Mg-rich serpentine that retains less absorbed water in its silicate layers than saponite [START_REF] Barber | Matrix phyllosilicates and associated minerals in C2M carbonaceous chondrites[END_REF][START_REF] Howard | Classification of hydrous meteorites (CR, CM and C2 ungrouped) by phyllosilicate fraction: PSD-XRD modal mineralogy and planetesimal environments[END_REF]. It is unclear why the CV trend is separate from the CI-CM trend, but the amount of H lost during pre-degassing suggests that this group of chondrites is also very sensitive to terrestrial alteration and can absorb similar H proportions as CM chondrites (Fig. 6). Phyllosilicates are modally less abundant in CV (up to 4 vol.%; [START_REF] Howard | Modal mineralogy of CV3 chondrites by X-ray diffraction (PSD-XRD)[END_REF] than in CM chondrites (~75 vol.%; [START_REF] Howard | Classification of hydrous meteorites (CR, CM and C2 ungrouped) by phyllosilicate fraction: PSD-XRD modal mineralogy and planetesimal environments[END_REF].

Assuming that phyllosilicates are the main storage sites for atmospheric moisture in hydrated carbonaceous chondrites, water adsorption should be vastly lower in CV than in CM chondrites (even accounting for the mineralogical differences of their phyllosilicates).

Alternatively, CI and CM phyllosilicates are almost water saturated-i.e., their water adsorption capacity is limited-whereas CV phyllosilicates, despite being less abundant, have more adsorption sites available for accommodating atmospheric moisture. Whatever the reason, it is apparent that terrestrial contamination can greatly affect the H budgets of the most H-poor (CV-like) and H-rich (CI-like) chondrites alike (Figs. 5 and6). The bulk H contents and D/H ratios of chondrites should thus be measured after pre-degassing under vacuum at ≥120 °C. The consequences of correcting the H compositions of chondrites for terrestrial contamination are discussed in §4.3.

The influence of thermal metamorphism

CV-type carbonaceous chondrites

CV chondrites are divided into three subgroups partly reflecting their various aqueous and thermal alteration histories: reduced, CV Red ; oxidized Allende-like, CV OxA ; and oxidized Bali-like, CV OxB . Of the oxidized CVs, the CV OxB subgroup is the most extensively altered and contains abundant phyllosilicates and chondrules replaced by phyllosilicates and magnetite. In contrast, the CV OxA and CV Red subgroups contain minor phyllosilicates and abundant Ca-Fe-rich secondary phases such as andradite, hedenbergite, and kirschsteinite [START_REF] Krot | Multiple formation mechanisms of ferrous olivine in CV carbonaceous chondrites during fluid-assisted metamorphism[END_REF][START_REF] Brearley | The action of water[END_REF][START_REF] Howard | Modal mineralogy of CV3 chondrites by X-ray diffraction (PSD-XRD)[END_REF][START_REF] Ganino | Reduced and unstratified crust in CV chondrite parent body[END_REF]. CV3s have experienced various degrees of metamorphism that are partly overprinted by subsequent aqueous alteration and further obscured by brecciation [START_REF] Bonal | Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter[END_REF]. Based on the maturation grade of their organic matter, [START_REF] Bonal | Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter[END_REF] assigned a range of petrographic degrees for the CV chondrites Kaba (~3.1), Vigarano (3.1-3.4), Bali and Grosnaja (~3.6), and Allende (>3.6), although they highlighted the occurrence of clasts of different petrologic types within individual meteorites (e.g., Bali). The H-, C-, and N-concentrations and isotopic compositions measured for these CV chondrites reflect the complex inputs of brecciation and aqueous and thermal alteration, with no clear behavior of these elements and isotopes with increasing petrologic type (Figs. 6 and7a; Tables 1 and2). Nevertheless, the most metamorphosed CV OxA , Allende, presents the lowest H concentrations, with its most Hdepleted lithologies [START_REF] Yang | Interstellar organic matter in meteorites[END_REF] having similar H contents as the metamorphosed CK4 Karoonda (Fig. 7a). This result suggests that thermal metamorphism of CV chondrites could induce a significant H loss for petrologic types >3.6 (Fig. 7a).

Ordinary chondrites

Ordinary chondrites (OCs) from the H, L, and LL groups exhibit pervasive imprints of thermal metamorphism and, to a lesser degree, aqueous alteration. Semarkona (LL3.00) and Bishunpur (LL3.15) are among the rare unequilibrated OCs to contain hydrated minerals (smectites) and other secondary phases (calcites) thought to have formed on their parent body from an oxidizing fluid [START_REF] Alexander | The microstructure of Semarkona and Bishunpur[END_REF]. Water measured in these chondrites is enriched in D, as attested by (i) their bulk D/H values up to 600 × 10 -6 [START_REF] Mcnaughton | Deuterium enrichments in type 3 ordinary chondrites[END_REF][START_REF] Yang | Interstellar organic matter in meteorites[END_REF]) and (ii) in-situ measurements of D/H values up to 1800 × 10 -6 [START_REF] Deloule | Interstellar water in meteorites?[END_REF][START_REF] Piani | Micron-scale D/H heterogeneity in chondrite matrices: A signature of the pristine solar system water? Earth Planet[END_REF]. Such high D enrichments were interpreted either as inherited from the accretion of D-rich ice that originated in cold regions of the solar system [START_REF] Deloule | Interstellar water in meteorites?[END_REF][START_REF] Piani | Micron-scale D/H heterogeneity in chondrite matrices: A signature of the pristine solar system water? Earth Planet[END_REF] or as the result of parent-body processes [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. Bleached chondrules found in LL3, L3, and more rarely in H3 chondrites attest that aqueous alteration was widespread in OCs, but was mostly erased by subsequent thermal metamorphism [START_REF] Grossman | Bleached chondrules: Evidence for widespread aqueous processes on the parent asteroids of ordinary chondrites[END_REF]. This later metamorphic event resulted in high degrees of equilibration of the three OC sub-groups spanning petrological types 3-7 and equilibration temperatures up to 1000 °C [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF].

The five OCs measured herein span the range of H concentrations reported in OCs, with the most metamorphosed chondrites (H6 Kernouve) being the most depleted in hydrogen (Fig. 7B). These five OCs exhibit D/H ratios similar to those previously measured in equilibrated ordinary chondrites (~130-160 × 10 -6 ), and we observe no strong differences between groups or petrological types (Fig. 7B). Furthermore, we do not observe D enrichments with increased parent-body thermal metamorphism (Fig. 7B), in agreement with previous observations [START_REF] Robert | Deuterium concentration in the early Solar System: hydrogen and oxygen isotope study[END_REF][START_REF] Mcnaughton | Deuterium enrichments in type 3 ordinary chondrites[END_REF]. This is at odds with the assumption that water in ordinary chondrites became increasingly enriched in deuterium due to the oxidation of iron and subsequent loss of isotopically light H 2 [START_REF] Alexander | Deuterium enrichments in chondritic macromolecular material-Implications for the origin and evolution of organics, water and asteroids[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF][START_REF] Sutton | The bulk valence state of Fe and the origin of water in chondrites[END_REF]. This assumption was initially proposed to explain the deuterium enrichment of IOM in OCs with increasing degree of metamorphism, the organic matter thereby being enriched by isotopic exchange with the remaining D-rich water [START_REF] Alexander | Deuterium enrichments in chondritic macromolecular material-Implications for the origin and evolution of organics, water and asteroids[END_REF]. However, given that both the remaining water and OM should have been enriched in D by this process, the bulk D/H ratios of OCs should increase with increasing degree of thermal metamorphism. The absence of such D enrichments in the bulk chondrites thus contradicts the implication of water in the D enrichment of the OM, instead supporting the proposal that ordinary chondrites contain a thermally recalcitrant D-rich organic matter component [START_REF] Remusat | Thermal recalcitrance of the organic D-rich component of ordinary chondrites[END_REF]. Overall, thermal metamorphism in OCs seems to have mainly decreased the bulk-rock hydrogen contents without strongly influencing the hydrogen isotopic ratios for petrological types ≥3.2 (Fig. 7B).

The percentage of fayalite (%Fa) in ordinary chondrites increases from H to L to LL groups and is considered a robust proxy of the degree of hydration (i.e., the water content) of their respective parent bodies [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF][START_REF] Florin | Influence of redox processes on the germanium isotopic composition of ordinary chondrites[END_REF]. However, the lack of variation between the H contents of the different groups of OCs (Fig. 7B) suggests that they could have accreted similar amounts of water. This could be interpreted as evidence for preaccretion hydration processes in different regions of the protoplanetary disk. Whereas there is no clear limit between the H contents of unequilibrated and equilibrated OCs, the observed decrease in H contents with increasing metamorphism is in line with the progressive increase of %Fa and the loss of Fe-Ni metal during metamorphism [START_REF] Florin | Influence of redox processes on the germanium isotopic composition of ordinary chondrites[END_REF].

Implication for the origin and abundance of H in chondrites

Our data suggest that terrestrial contamination can represent a significant part of the measured chondritic H budget, which strongly depends on the analytical protocol and particularly the pre-degassing procedure. The effects of terrestrial contamination are especially important for chondrites with the highest indigenous hydrogen contents within a given chondrite group (Figs. 4 and6). However, within errors, we observe similar positive correlations and zero intercepts (D/H ~ 100 × 10 -6 or D ~ -400‰) between D/H and C/H for CMs (Fig. 8) as previously reported [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. These values represent the isotopic composition of water accreted by the CM parent body [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. This similarity indicates that previous estimations of the D/H ratios of water in the region of CM parent-body accretion [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] were not significantly affected by terrestrial contamination, as also attested by the consistency with in-situ measurements via secondary ion mass spectrometry (SIMS; Piani et al., 2018). The D/H ratio of water accreted by CV chondrites was only estimated recently from SIMS measurements [START_REF] Piani | Hydrogen isotopic composition of water in CV-type carbonaceous chondrites[END_REF], and our bulk data confirm their observation that CV water is enriched in deuterium compared to CM water (Fig. 8). If CMs and CVs accreted beyond the orbit of Jupiter as commonly proposed [START_REF] Kruijer | Age of Jupiter inferred from the distinct genetics and formation times of meteorites[END_REF][START_REF] Nanne | Origin of the non-carbonaceouscarbonaceous meteorite dichotomy[END_REF], this suggests the existence of different water-ice reservoirs, with CV water being enriched in heavy H and O isotopes (Piani et al., 2018;[START_REF] Piani | Hydrogen isotopic composition of water in CV-type carbonaceous chondrites[END_REF][START_REF] Marrocchi | Origin and abundance of water in carbonaceous asteroids[END_REF].

Among chondrites, CIs are of primary importance as their bulk chemical compositions are similar to that of the solar photosphere, which is representative of the average solar system composition [START_REF] Lodders | Solar system abundances and condensation temperatures of the elements[END_REF]. In addition, CIs are generally considered to be the most hydrated chondrites based on previous H measurements [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] and their high abundances of secondary minerals (~ 97%; [START_REF] King | Modal mineralogy of CI and CI-like chondrites by X-ray diffraction[END_REF].

Although it remains a possibility that a small amount of the released water below 120°C could have been initially indigenous, our data reveal that CIs analyzed without pre-degassing are essentially contaminated by terrestrial moisture, and we estimate their indigenous water contents to be almost a factor of 2 lower than previously reported (0.93 wt.% H compared to 1.56 wt.% H; [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF], in agreement with results from stepwise heating analyses [START_REF] Boato | The isotopic composition of hydrogen and carbon in the carbonaceous chondrites[END_REF][START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Yang | Interstellar organic matter in meteorites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF][START_REF] Eiler | Hydrogen isotope evidence for the origin and evolution of the carbonaceous chondrites[END_REF]. Consequently, CI chondrites have indigenous water contents similar to those estimated for CM chondrites, suggesting that CIs and CMs accreted similar proportions of water, although they contain vastly different proportions of matrix (65 vol.% and 100 vol.% in CMs and CIs, respectively; Alexander et al., 2018b and references therein). CV chondrites comprising 40 vol.% matrix have H abundances roughly one tenth those of CM and CI chondrites. Together, our results for CV-, CM-, and CI-type carbonaceous chondrites argue against the suggested dependency of the bulk H concentration on matrix content (Alexander et al., 2018b). Nevertheless, our data for C and N concentrations (Fig. 3) are consistent with a matrix content dependency for these elements (Alexander et al., 2018b). Furthermore, correcting for terrestrial water contamination in CIs largely affects their D/H isotopic compositions, which is not the case for CMs (Fig. 5). This implies that CIs do not have H isotopic ratios as close to that of Earth's water as previously estimated based on measurements performed without pre-degassing. This conclusion was reported nearly 40 years ago [START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF], but was overshadowed by recent studies that did not quantify the effects of terrestrial contamination [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. Consequently, the large contamination of CI water and its nonterrestrial H isotopic composition should be accounted for in models of Earth's formation based on the mixing of chondrite-like materials, as considering CIs as the putative source of Earth's oceans would also affect the 54 Cr mass balance calculation [START_REF] Warren | Stable-isotopic anomalies and the accretionary assemblage of the Earth and Mars: A subordinate role for carbonaceous chondrites[END_REF][START_REF] Dauphas | The isotopic nature of the Earth's accreting material through time[END_REF]. In such a framework, CM chondrites thus appear to be the most isotopically similar extraterrestrial materials to the Earth's surficial hydrogen reservoir.

Conclusions

We have determined the bulk hydrogen concentrations and isotopic compositions of a large set of chondritic samples (CI, CM, CV, CK, and ordinary chondrites) using an elemental analyzer coupled to an isotope ratio mass spectrometer. Samples were pre-degassed under vacuum at 120 °C for 48 h before measurements. Our main results are:

1) CI and CM chondrites and Tagish Lake define a correlation in a D/H vs. 1/H diagram induced by the increasing contribution of insoluble organic matter to the total H budget. This trend is statistically distinct from that defined by similar chondrites analyzed without pre-degassing at ≥120 °C.

2) No clear D enrichment is observed with the increase of parent-body thermal metamorphism for ordinary and CV-type carbonaceous chondrites.

From these results, we drew the following conclusions: 1) Chondrites are largely affected by terrestrial contamination, with the most hydrated CI chondrites being the most prone to contamination because phyllosilicates are more abundant in CIs compared to CMs and CVs. After correction of contamination, the primordial H contents of CI, CM, and CV chondrites are significantly lower than generally reported and is not related to their matrix modal abundance, implying that their respective parent bodies accreted variable amounts of water-ice grains.

2) The D/H ratio of Orgueil is affected by terrestrial contamination, leading to an important underestimation of its H isotopic composition. This result is important as it could affects the amount of water delivery by CI chondrites in the models of Earth's formation based on the mixing of chondrite-like materials.

3) Although based on a limited number of samples, thermal metamorphism suggests that significant H were lost in CVs of petrological type >3.6. It also decreased the H contents of ordinary chondrites, but minimally affected the D/H ratios of OCs of petrological type ≥3.2.

4) The absence of an increasing D/H ratio with increasing the metamorphism degree for bulk ordinary chondrites does not support models in which water became enriched in deuterium via the oxidation of iron and the loss of isotopically light H2. On the contrary, this observation supports the presence of thermally resistant D-rich organic matter in ordinary chondrites. [START_REF] Boato | The isotopic composition of hydrogen and carbon in the carbonaceous chondrites[END_REF], [START_REF] Robert | Teneur en eau et en deuterium des chondrites[END_REF], [START_REF] Robert | Deuterium concentration in the early Solar System: hydrogen and oxygen isotope study[END_REF], [START_REF] Kolodny | Deuterium in carbonaceous chondrites[END_REF], [START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF], [START_REF] Mcnaughton | Deuterium enrichments in type 3 ordinary chondrites[END_REF], [START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF], [START_REF] Yang | Interstellar organic matter in meteorites[END_REF], [START_REF] Robert | The D/H ratio in chondrites[END_REF], [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. Measured hydrogen concentrations decrease and D/H ratios increase with increased predegassing temperature for Orgueil. Ranges of D/H values of D-rich organic matter (dark gray area; [START_REF] Alexander | The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter[END_REF], D-poor phyllosilicates (light gray area; [START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]Piani et al., 2018[START_REF] Piani | Hydrogen isotopic composition of water in hydrated chondrites[END_REF] and terrestrial hydrosphere (blue area; [START_REF] Lécuyer | The hydrogen isotope composition of seawater and the global water cycle[END_REF][START_REF] Frankenberg | Dynamic Processes Governing Lower-Tropospheric HDO/H 2 O Ratios as Observed from Space and Ground[END_REF][START_REF] Clog | The hydrogen isotopic composition and water content of southern Pacific MORB: A reassessment of the D/H ratio of the depleted mantle reservoir[END_REF] are also represented for comparison. Data from: [START_REF] Boato | The isotopic composition of hydrogen and carbon in the carbonaceous chondrites[END_REF], [START_REF] Kolodny | Deuterium in carbonaceous chondrites[END_REF], Robert and Epstein ('R&E', 1982), Yang and Epstein ('Y&E', 1983), [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF]. Fig. 6. The amount of H lost during the pre-degassing procedure as a function of the indigenous H content measured in CV-, CM-, and CI-type carbonaceous chondrites after predegassing at 120 °C. The amount of pre-degassed H is calculated as the difference between the hydrogen content measured in our samples after pre-degassing at 120 °C and that measured in the same samples at room temperature (25 °C) using the same analytical technique, but without pre-degassing [START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] (errors are 2σ). Fig. 7. Bulk D/H ratios as a function of bulk hydrogen abundances (expressed as 1/H) for all reported analyses of (A) CV chondrites (this study ;[START_REF] Boato | The isotopic composition of hydrogen and carbon in the carbonaceous chondrites[END_REF][START_REF] Robert | The concentration and isotopic composition of hydrogen, carbon and nitrogen in carbonaceous meteorites[END_REF][START_REF] Kerridge | Carbon, hydrogen and nitrogen in carbonaceous chondrites: Abundances and isotopic compositions in bulk samples[END_REF][START_REF] Pearson | Hydrogen isotopic composition of the Tagish Lake meteorite: Comparison with other carbonaceous chondrites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] and (B) ordinary chondrites (this study; [START_REF] Robert | Deuterium concentration in the early Solar System: hydrogen and oxygen isotope study[END_REF][START_REF] Mcnaughton | Deuterium enrichments in type 3 ordinary chondrites[END_REF][START_REF] Yang | Interstellar organic matter in meteorites[END_REF][START_REF] Alexander | The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets[END_REF] (errors are 2σ).

Figure captions

  25 °C, [H] 120 °C, D/H 25 °C, and D/H 120 °C correspond to the bulk H concentrations and isotopic compositions of the samples determined at room temperature (i.e., 25 °C) and after pre-degassing at 120 °C for 48 h, respectively. The hydrogen lost during pre-degassing corresponds to [H] lost = [H] 25 °C -[H] 120 °C. Consequently, if the H lost during pre-degassing was adsorbed terrestrial water, its calculated H isotopic composition should be (i) similar from one sample to the next and (ii) within the range of terrestrial values. On the other hand, large H isotopic variations are expected if the H lost resulted from sample heterogeneity or the removal of indigenous hydrogen. The H isotopic compositions of pre-degassed H range from D/H ~ 150-155 × 10 -6 for Murchison, Mighei, Murray, and Orgueil. These values are in the range of H isotopic ratios reported for terrestrial hydrosphere reservoirs (115-165 × 10 -6 ;

  probably derives from the fact that the bulk D/H values of CMs, which result from the combined contributions of D-poor water and D-rich OM, are fortuitously close to the D/H values imparted by atmospheric contamination (D/H CM ~ 142 × 10 -6 vs. D/H [H] lost ~ 150 × 10 - 6 ), and contamination thus produces only minor changes. In contrast, water and OM in CIs are D-rich compared to CMs

Fig. 1 .

 1 Fig. 1. Schematic representation of the analytical protocol used in this study. The samples

Fig. 2 .

 2 Fig. 2. (A) Average bulk hydrogen and water abundances (wt.%) for the different groups of

Fig. 3 .

 3 Fig. 3. Relationship between bulk carbon and nitrogen abundances (wt.%) for all chondrites

Fig. 4 .

 4 Fig. 4. Bulk hydrogen abundances (expressed as 1/H) and D/H isotopic ratios of CM

Fig. 5 .

 5 Fig. 5. The effect of pre-degassing temperature on the measured (A, B) hydrogen abundances

Fig. 8 .

 8 Fig. 8. Bulk hydrogen isotopic compositions of CV (black) and CM (red) chondrites as a

  Fig. 1

Table 1 :

 1 Hydrogen abundances and isotopic compositions of chondrites. 920 921

		Meteorite		Type	wt% H	err. (2σ)	2 sd	δD (‰)	err. (2σ)	2 sd	D/H (×10 -6 )	err. (2σ)	2 sd
	Aguas Zarcas (n =2)	CM2	0.868	0.045	0.087	-107.1	2	1.6	139.1	0.3	0.3
	Jbilet Winselwan (n = 2)	CM2	0.471	0.032	0.018	-38.9	2	9.5	149.7	0.3	1.5
	LON 94101 (n = 2) c	CM2	0.832	0.045	0.012	-154.6	2	3.1	131.7	0.3	0.5
		Maribo (n = 2)	CM2	0.794	0.044	0.028	-37.9	2	1.1	149.9	0.3	0.2
		Mighei (n = 2)	CM2	0.910	0.047	0.038	-109.4	2	0.8	138.7	0.3	0.1
	Mukundpura (n = 4)	CM2	1.013	0.048	0.139	-158.2	2	6.7	131.1	0.3	1
	Murchison (n = 2)	CM2	0.828	0.046	0.081	-74.9	2	0.9	144.1	0.3	0.1
		Murray (n = 2)	CM2	0.842	0.046	0.038	-18.5	2	2.6	152.9	0.3	0.4
	Paris (altered area) a	CM2	0.686	0.040		93.7	2		170.4	0.3
		Paris b		CM2	0.530	0.010		120.3	1		174.5	0.3
	Tagish Lake (n = 3)	Ung. C	0.433	0.031	0.007	442.3	2	24	224.7	0.3	3.7
		Alais (n = 2)	CI	0.963	0.048	0.092	133.7	2	28.9	176.6	0.3	4.5
		Orgueil (n = 4)	CI	0.930	0.045	0.148	138.0	2	15.3	177.3	0.3	2.4
	Y-980115 (n = 3) d	CY	0.710	0.041	0.212	-106.0	2	3	139.2	0.3	0.5
		Allende (n = 2)	CV	0.068	0.011	0.011	-109.9	2	2.4	138.6	0.8	0.4
		Bali		CV	0.060	0.010		-9.3	5		154.3	0.8
		Grosnaja		CV	0.191	0.019		-90.5	5		141.7	0.8
		Kaba		CV	0.110	0.014		32.6	5		160.8	0.8
		Vigarano		CV	0.158	0.018		-72.6	5		144.5	0.8
		Karoonda		CK	0.013	0.004		-107.4	5		139.0	0.8
		Bjurbole		LL/L4	0.053	0.009		-128.1	5		135.8	0.8
		GRO 95502	e	L3	0.199	0.020		-73.2	5		144.4	0.8
		Saratov (n = 2)	L4	0.029	0.006	0.011	-113.7	5	2.3	138.1	0.8	0.4
	Sainte Marguerite	H4	0.010	0.004		-135.8	5		134.6	0.8
		Kernouve		H6	0.008	0.003		-138.3	5		134.2	0.8
	923
	924	Err. (2σ): 2σ sample error (see methods). 2 sd: 2σ standard deviation on n replicates.
	925

a Piece of Paris provided by Bekaert et al. (2018). b Data from Vacher et al. (2016) using the same 922 methodology as this study. c Lonewolf Nunataks 94101. d Yamato 980115. e Grosvenor Mountains.

Table 2 :

 2 Carbon and nitrogen abundances and carbon isotopic compositions of chondrites.Err. (2σ): 2σ sample error (see methods), 2 sd: 2σ standard deviation on n replicates.

	Meteorite			Type	wt% N	err. (2σ)	2 sd	wt% C	err. (2σ)	2 sd	δ 13 C (‰)	err. (2σ)	2 sd
	Aguas Zarcas	CM2	0.098	0.029		2.13	0.04		-9.8	0.2
	Jbilet Winselwan	CM2	0.095	0.029		1.54	0.03		-10.9	0.2
	LON 94101	a	CM2	0.102	0.031		1.91	0.04		-13.7	0.2
	Maribo			CM2	0.114	0.034		2.18	0.04		-5.5	0.2
	Mighei			CM2	0.103	0.031		2.92	0.06		-12.5	0.2
	Mukundpura (n = 3)	CM2	0.086	0.086 0.008	2.08	0.04	0.04	-3.9	0.2	2.3
	Murchison			CM2	0.092	0.092		2.30	0.05		-10.4	0.2
	Murray			CM2	0.134	0.040		3.04	0.06		-11.7	0.2
	Paris			CM2	0.172	0.052		2.67	0.05		-7.5	0.2
	Tagish Lake	Ung. C	0.112	0.034		2.14	0.04		4.7	0.2
	Alais			CI	0.173	0.052		3.33	0.07		-15.9	0.2
	Orgueil (n = 2)	CI	0.205	0.062 0.014	3.35	0.07	0.78	-12.9	0.2	5.7
	Y-980115 b			CY	0.090	0.090		3.06	0.06		-12.9	0.2
	Allende			CV	0.012	0.012		0.55	0.01		-23.7	0.2
	Bali			CV	bdl			0.85	0.02		-19.9	0.2
	Grosnaja			CV	0.034	0.034		0.51	0.01		-21.6	0.2
	Kaba			CV	0.030	0.030		1.42	0.03		-17.8	0.2
	Vigarano			CV	bdl			bdl			bdl	0.2
	Karoonda			CK	bdl			0.09	0.00		-20.7	0.2
	Bjurbole			LL/L4	bdl			0.14	0.00		-26.5	0.2
	GRO 95502	c	L3	bdl			bdl			bdl	0.2
	Saratov			L4	bdl			0.12	0.00		-26.2	0.2
	Sainte Marguerite	H4	bdl			0.08	0.00		-24.7	0.2
	Kernouve			H6	bdl			0.10	0.00		-26.6	0.2
	a Lonewolf Nunataks 94101,

b Yamato 980115 c Grosvenor Mountains.

Acknowledgments

We thank Mike Zolensky and Bernard Marty for providing samples. We also thank the

National

Institute of Polar Research (Japan), the Natural History Museum of Denmark (Copenhagen), the Muséum national d'Histoire naturelle (Paris, France), the Natural History Museum of Vienna (Austria), and the Antarctic Search for Meteorites (ANSMET) program for loaning samples. US Antarctic meteorite samples were recovered by ANSMET, funded by NSF and NASA, and characterized and curated by the Department of Mineral Sciences of the Smithsonian Institution and Astromaterials Curation Office at NASA Johnson Space Center. This work was funded by l'Agence Nationale de la Recherche through grant ANR-14-CE33-0002-01 SAPINS (PI Yves Marrocchi) and ANR-19-CE31-0027-01 HYDRaTE (PI Laurette Piani) and by the European Research Council (PHOTONIS project, grant agreement No. 695618 to Bernard Marty). This is a CRPG contribution #2728.

Research data

Original data of this study are available in the supplementary file.