Guillaume Florin
email: guillaume.florin@univ-lorraine.fr

Béatrice Luais

Tracy Rushmer

Olivier Alard

Influence of redox processes on the germanium isotopic composition of ordinary chondrites

Ordinary chondrites (OCs) are classified into three groups, according to their oxidation state, which increases from the H to L to LL groups. This is demonstrated by the decrease in metal content (H=~8 vol%, L=~4 vol%, and LL=~2 vol%), and by a positive correlation between Δ 17 O and %Fa through the OC sequence. Compared to other chondrites, OCs exhibit the largest variation in oxidation state but there is an ongoing debate on the processes that control this variation. To constrain the causes of the variations in the oxidation state with respect to the associated nebular versus parent bodies processes, we investigated the elemental and isotopic isotopic metal-silicate datasets, such as the magmatic iron meteorites, the Earth silicate reservoirs. We propose that the Δ 74/70 Ge metal-silicate and the negative δ 74/70 Ge values of OCs are inherited from metal-silicate melting and partial exchange before planetesimal accretion in a light isotope-enriched gas. Finally, the δ 74/70 Ge metal -Δ 17 O silicate correlation between the IIE iron meteorites and OCs, provides new evidence for the existence of a highly reduced HH group.

variations of germanium (moderately siderophile and volatile) in the bulk sample, as well as in the metal, silicate and sulfide phases, over a range of petrographic types for the H, L, and LL ordinary chondrites.

We found that δ 74/70 Ge metal is a proxy for the δ 74/70 Ge bulk composition and that each OC group is distinguishable by their δ 74/70 Ge metal , which increases from -0.51±0.09‰ for H chondrites, -0.31±0.06‰ for L chondrites, and, finally, to -0.26±0.09‰ for LL chondrites (2σSD).

Additionally, the OC sequence exhibited a positive correlation, from H to L to LL, between δ 74/70 Ge metal and %Fa, as well as oxygen isotopes (δ 17 O, δ 18 O and Δ 17 O), that was not a consequence of a "size sorting effect" on chondrules (i.e. chondrule mixing) or metamorphic processes in the parent bodies but, rather, was the result of nebular processes. We propose that the correlation between the δ 74/70 Ge values and %Fa, Δ 17 O, δ 18 O can be explained by an increasing proportion of accreted hydrated phyllosilicates, from the H, L to LL groups, with high δ 74/70 Ge and Δ 17 O. We found that 10 to 15% of phyllosilicates, with a composition of [Ge]=4-7 ppm and δ 74/70 Ge=3-2.5‰, is needed to change the δ 74/70 Ge from H to LL, which corresponds to a Δ 17 O≈8-7‰. This value agrees with the Δ 17 O≈7‰ composition of the accreted nebular component reported by [START_REF] Choi | Extreme oxygen-isotope compositions in magnetite from unequilibrated ordinary chondrites[END_REF]. During thermal metamorphism, phyllosilicates destabilize, liberating germanium that will be incorporated in the metal, then leading to its high δ 74/70 Ge signature.

High-temperature metamorphism can explain the lack of δ 74/70 Ge metal variation with the petrologic type in the OC, even for the type 3 chondrites (T≈675°C), implying a complete reaction even at low petrologic types. In addition, metal-silicate re-equilibration in response to thermal metamorphism results in a decrease in Δ 74/70 Ge metal-silicate from 0.33‰ to 0.06‰, within the H chondrite group, which is interpreted as the result of δ 74/70 Ge silicate variation. The mean positive Δ 74/70 Ge metal-silicate fractionation factor of +0.22±0.36‰ (error propagation on individual error) also displays a remarkable similarity to the direction of isotopic fractionation with other germanium 1. Introduction Ordinary chondrites (OCs) are undifferentiated meteorites that formed in the first 1 to 3 Myr after the formation of refractory Calcium-Aluminium Inclusions (CAIs) [START_REF] Kleine | Hf-W thermochronometry: Closure temperature and constraints on the accretion and cooling history of the H chondrite parent body[END_REF][START_REF] Archer | Siderophile element constraints on the thermal history of the H chondrite parent body[END_REF][START_REF] Hellmann | Hf-W chronology of ordinary chondrites[END_REF], as well as during a short accretion time interval of less than 0.5 Myr [START_REF] Monnereau | Thermal history of the H-chondrite parent body: Implications for metamorphic grade and accretionary time-scales[END_REF]. OCs also postdate magmatic iron meteorite formation. Several studies argue for their formation via the disruption-re-accretion of early-differentiated planetesimals [START_REF] Elkins-Tanton | Chondrites as samples of differentiated planetesimals[END_REF][START_REF] Lichtenberg | Impact splash chondrule formation during planetesimal recycling[END_REF]. As a result, OCs should represent a record between the early formed planetesimals and terrestrial planets as we know them today.

Ordinary chondrites are composed of an assemblage of chondrules and matrix, which contain silicates, FeNi alloys, sulfides, and rare CAIs. The OC sequence has been classified into three groups, i.e., H (High metallic Fe content), L (low metallic Fe content) and LL (low total Fe and low metallic Fe content), according to the oxidized iron content relative to the metal iron [START_REF] Urey | The composition of the stone meteorites and the origin of the meteorites[END_REF], oxygen isotopic composition [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF], bulk volatile elemental concentration, including water, and chondrule size [START_REF] Wasson | Formation of ordinary chondrites[END_REF][START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF]Chou et al., 1973;[START_REF] Kallemeyn | Ordinary chondrites: Bulk compositions, classification, lithophile-element fractionations and composition-petrographic type relationships[END_REF]Wasson, 2000;[START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF]. Each chondrite group is thought to originate from at least one parent body and are subdivided into petrologic types, from the least metamorphosed and unequilibrated (group 3) to the most metamorphosed and highly equilibrated (group 6;[START_REF] Van Schmus | A chemical-petrologic classification for the chondritic meteorites[END_REF]. Studies on OC ages, cooling times, and petrographic types led to the creation of the "onion-shell" model in which thermal metamorphism increases with planetesimal depth [START_REF] Göpel | U/Pb systematics of phosphates from equilibrated ordinary chondrites[END_REF]. With increasing petrographic type, the temperature [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF] and oxidation state increase [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF]Chou et al., 1973;[START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF], metallic iron content decreases, and metal becomes more equilibrated with silicate through oxidation reactions [START_REF] Mcsween | Oxidation during metamorphism of the ordinary chondrites[END_REF]. Moreover, as thermal metamorphism increases, the metal grain-size, as well as the grain circularity, increase, which define additional parameters for characterizing the petrologic types [START_REF] Guignard | Textural properties of iron rich phases in H ordinary chondrites and quantitative links to the degree of thermal metamorphism[END_REF].

The percentage of fayalite in olivine (%Fa) is commonly used as a redox proxy (Chou et al., 1973;[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] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] first showed that there was an increase in the oxygen isotopic composition from the H to LL groups, which led [START_REF] Mcsween | Oxidation during metamorphism of the ordinary chondrites[END_REF] and [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF] to demonstrate that there is a positive correlation between %Fa and the oxygen isotopic composition throughout the OC sequence. This implies that variations in δ 18 O and Δ 17 O are related to the oxidation state. However, the origin of oxidation processes remains highly controversial. Previous studies have argued that this evolution reflects primitive conditions in the solar nebula recorded by planetesimals through progressive accretion of high Δ 17 O nebula water hosted in phyllosilicates (i.e. [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF]. Thermal metamorphism, induced by heat release from the decay of short-lived radioactive elements ( 26 Al), liberates heavy-O water, which produces both an increase in the oxidation state and oxygen isotopic composition. On the other hand, the oxidation state can also be explained by an increase in the proportion of type II chondrules (oxidized) and the decrease of type I chondrules (reduced) from H to LL. Type I is reduced, O 16 -rich, and contain metallic Fe, whereas type II is oxidized, 16 O-depleted, and Fe is present in an oxidized form [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF]. [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF] and Chou et al. (1973) have shown that OCs groups are also resolvable using the siderophile element concentration, e.g., the germanium content in the metal increases from H to LL with the Ni content, as a proxy of the redox state. They proposed that a significant proportion of Ge condenses in the silicate at its formation, such that Ge is redistributed between the metal and silicate through oxidationreduction during metamorphic processes on their parent bodies.

Germanium is a moderately siderophile and volatile element (T 50% condensation = 883K at pH 2 O/pH 2 = 4.2 * 10 -4 atm; [START_REF] Lodders | Abundances of the elements in the solar system[END_REF], commonly used with Ir, Au, and Ni to constrain the formation of iron meteorites and metal phases in chondrites [START_REF] Wasson | Meteorites: Classification and Properties[END_REF]. Experimental studies have shown that Ge partitioning between metal and silicate phases is strongly redoxdependent, with D(Ge) metal-silicate values greater than 10 4 under highly reduced conditions (-2.7 log fO 2 relative to the IW buffer; [START_REF] Kegler | Determination of the formal Ge-oxide species in silicate melts at oxygen fugacities applicable to terrestrial core formation scenarios[END_REF]. Germanium is also a chalcophile element but the amount of Ge in troilite (FeS) from the OCs represents only 3 to 5% (0.3 to 0.5 ppm) of the total amount of Ge in OCs [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF][START_REF] Wai | Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites[END_REF], whereas it is strongly concentrated, i.e., up to several hundred ppm, in terrestrial lowtemperature sulfides [START_REF] Bernstein | Germanium geochemistry and mineralogy[END_REF].

Germanium has five stable isotopes, i.e., 70 Ge, 72 Ge, 73 Ge, 74 Ge, and 76 Ge, with the Ge isotopic composition given as a delta notation: δ 74/70 Ge = (( 74 Ge/ 70 Ge Sample / 74 Ge/ 70 Ge Standard ) -1) × 1000. To date, previous studies have analyzed the germanium isotopic composition of differentiated bodies that experienced metal-silicate segregation to investigate the conditions and processes of planetary differentiation. Magmatic iron meteorites that represent planetesimal cores display positive and heavier Ge isotopic compositions than the Earth's mantle and crust [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF][START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF]. The Ge isotopic composition of the Earth's silicate reservoir is, thus far, homogeneous and has not been significantly modified by complex crust-mantle exchange via fluids in subduction zones [START_REF] Korh | Investigation of Ge and Ga exchange behaviour and Ge isotopic fractionation during subduction zone metamorphism[END_REF].The volatile behavior of germanium can also be responsible for large Ge isotopic fractionations that occur in IIE non-magmatic iron meteorites [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF], which form due to metal segregation following impact-driven melting at the sub-surface of their parental bodies [START_REF] Wasson | A nonmagmatic origin of group-IIE iron meteorites[END_REF][START_REF] Wasson | Formation of non-magmatic iron-meteorite group IIE[END_REF]. To date, the only constituents that display strong negative δ 74/70 Ge values are schreibersite (Fe-Ni-P) inclusions in iron meteorites [START_REF] Rouxel | Germanium Isotope Geochemistry[END_REF] and low-temperature terrestrial Zn-sulfides [START_REF] Belissont | LA-ICP-MS analyses of minor and trace elements and bulk Ge isotopes in zoned Ge-rich sphalerites from the Noailhac -Saint-Salvy deposit (France): Insights into incorporation mechanisms and ore deposition processes[END_REF]. Metal-silicate segregation, volatility, and phosphide/sulfide exsolution/crystallization are the main processes, currently known, that strongly fractionate germanium and its isotopes.

Germanium isotopes represent potential tools to investigate processes of formation and evolution of ordinary chondrites (1) during condensation of metal-silicate-sulfide from the solar nebula [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF][START_REF] Wai | Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites[END_REF], (2) by inheritance from previously destroyed planetesimals (Litchenberg et al., 2018), and (3) metal-silicate equilibrium fractionation on parent bodies following a major impact [START_REF] Tomkins | Disequilibrium melting and melt migration driven by impacts: Implications for rapid planetesimal core formation[END_REF] or after metamorphism [START_REF] Humayun | The duration of ordinary chondrite metamorphism inferred from tungsten microdistribution in metal[END_REF][START_REF] Guignard | Textural properties of iron rich phases in H ordinary chondrites and quantitative links to the degree of thermal metamorphism[END_REF]. In addition, ordinary chondrites provide a suitable environment to explore the relationships between Ge and O isotopes, as well as the redox conditions. The combined use of these data can establish constraints on the environment in which OCs form and the processes that lead to metal-silicate fractionation and equilibration.

Germanium isotopic measurements on separated phases from unequilibrated and equilibrated OCs are used to evaluate the effect that metamorphism has on metal-silicate isotope fractionation. [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] first proposed the genetic association between ordinary chondrites and IIE iron meteorites based on their oxygen isotopic compositions in silicate clasts.

The IIE-OCs relationship has been further constrained with Mo isotopic anomalies [START_REF] Burkhardt | Molybdenum isotope anomalies in meteorites: constraints on solar nebula evolution and origin of the Earth[END_REF][START_REF] Budde | Molybdenum isotopic evidence for the origin of chondrules and a distinct genetic heritage of carbonaceous and non-carbonaceous meteorites[END_REF]. Here, based on the Ge isotopic composition in the metal phase, we examine a new genetic link between IIE iron meteorites and H OCs.

Samples and methods

Sample selection

To constrain the metamorphic and shock effects on Ge systematics, sixteen OCs (eight H, six L, and two LL) were selected to represent all petrologic types (Van Schumus and [START_REF] Van Schmus | A chemical-petrologic classification for the chondritic meteorites[END_REF] and various shock stages as defined by [START_REF] Stöffler | Shock metamorphism of ordinary chondrites[END_REF]. In addition, two samples were specifically selected to assess the effect of shock: Rose City, an impact melt breccia, and Portales Valley, a low shock meteorite with large metal veins as an example of metal migration [START_REF] Ruzicka | Portales Valley: Petrology of a metallicmelt meteorite breccia[END_REF]. Table 1 summarizes the sample characteristics.

Analytical Procedures

Sample preparation

Approximately 500 mg of initial bulk meteorite material was cleaned with 0.2 M HNO 3 under cold ultrasonic agitation for 5 minutes. The acid was removed, the samples were rinsed with pure water under ultrasonic agitation and then rinsed with acetone to avoid metal oxidation.

Afterward, 300 mg of the meteorite sample was gently powdered in an agate mortar for bulk elemental and isotopic measurements.

Metal and sulfide separation. The remaining 200 mg of clean sample was gently crushed in an agate mortar. FeNi metal was removed from the crushed sample with a hand-magnet. The magnetic fraction was crushed multiple times in an agate mortar, followed by several minutes of ultrasonic agitation in an acetone medium to remove all silicate particles remaining on the metal surface. A Frantz magnetic separator was used to separate the sulfides from the remaining weakly magnetic powder. Between 10 and 40 mg of metal and 10 to 20 mg of sulfide were separated using these procedures.

Silicate separation. The crushed non-magnetic sample fraction that mostly contained impure silicates was gently grounded in an agate mortar to a fine powder. To remove the non-magnetic sulfides and small metal particles stuck on the silicates, two successive cleanings with 6 M HCl and 2 M HNO 3 were performed for 5 minutes under ultrasonic agitation at room temperature. As Ge is highly volatile when associated with HCl at a high temperature (T > 60°C), this protocol was first tested on San Carlos olivine samples to evaluate Ge loss. Uncleaned olivines have

[Ge] = 0.89 ± 0.02 ppm and δ 74/70 Ge = 0.70 ± 0.08‰ while clean olivines have [Ge] = 0.90 ± 0.02 ppm and δ 74/70 Ge = 0.71 ± 0.09‰ (Table 2), which demonstrates that there was no Ge loss nor isotopic fractionation during cold HCl leaching. This step is important because metallic phases are at least one hundred times more concentrated in germanium than silicates or sulfides [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF]. The presence of small metal particles on the silicate surface would have introduced a bias on the elemental and isotopic compositions of Ge in silicates.

Chondrule separation. Separation was only performed on Dhajala (H3.8). A total of 1 g of Dhajala was cleaned and gently crushed in an agate mortar to preserve the chondrules.

Unbroken chondrules were separated by hand-picking and sieved into two fractions, i.e., 100-300 µm and > 300 µm, with a recovery of 9.1 and 130.5 mg, respectively. All fractions were later checked and purified by hand-picking under a binocular microscope, successively cleaned with diluted HNO 3 , distilled H 2 O, and acetone under cold ultrasonic agitation, and dried under a laminar flow hood.

Sample digestion and chemical purification of germanium

The germanium chemistry analytical procedures for metal, sulfide, and silicate phases follow those described in [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF]Luais ( , 2012, references therein) , references therein) and [START_REF] Belissont | LA-ICP-MS analyses of minor and trace elements and bulk Ge isotopes in zoned Ge-rich sphalerites from the Noailhac -Saint-Salvy deposit (France): Insights into incorporation mechanisms and ore deposition processes[END_REF]. Samples were dissolved in Teflon beakers on a hotplate in concentrated HF-HNO 3 solutions for the silicate and sulfide fractions while metal phases were dissolved in an HNO 3 -only solution. Bulk samples were digested under pressure (25 bar) using Bola Teflon bombs at 150°C [START_REF] Luais | Comparative behavior of Sr, Nd and Hf isotopic systems during fluid-related deformation at middle crust levels[END_REF] for one week in an oven to ensure the dissolution of all phases, including chromite. To ensure that no Ge was lost at high temperatures under pressure, this protocol was tested using a BIR-1 geo-standard. We obtained a δ 74/70 Ge of 0.59 ± 0.10‰ for BIR-1 that was digested in the bomb while this was δ 74/70 Ge = 0.59 ± 0.06‰ for conventional hotplate BIR-1 dissolution. This demonstrates that there was no isotopic fractionation using this digestion method (Table 2).

Germanium purification from silicate and sulfide matrices was completed in two steps using ion exchange resins. First, anionic resin (AG1-X8 resin chloride form, 200 -400 mesh, Biorad, Hercules, CA, U.S.A.) allowed us to eliminate most elements (i.e., the alkalis, Mn, Al, Co, Ni, Zn, Ga, and most Fe) using 1 M HF. Germanium (± Fe, Mg) was eluted with 0.2 M HNO 3 .

Germanium purification from Fe and the remaining matrix was performed solely using cation exchange resin (AG 50W-X8, Biorad, 159 Hercules, CA, U.S.A.) and 0.5 M HNO 3 . Germanium isolation from the Fe-Ni matrix of the metal phase was performed only using the cation exchange resin step. These two procedures had a germanium yield of 100% within error [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF][START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF]. All acids used for digestion and germanium chemical separation were high-purity grade SeaStar® reagents.

Elemental measurements

Bulk powder samples and metal phase separates from H OCs, and metal from L samples were analyzed for major and trace elemental compositions including Ge at the SARM analytical facility (Service Analytique des Roches et des Minéraux, CRPG-Nancy) using a ThermoFischer ICP-MS X7. Errors associated with the Ge, Ni and Co measurement were < 5% for our sample concentrations. The separated mass of pure sulfides was low (i.e., approximately 10 -20 mg) due to their low occurrence in the OCs (~5.7%; [START_REF] Lauretta | The origin of sulfide-rimmed metal grains in ordinary chondrites[END_REF]. Similarly, only 10 -40 mg of pure silicate separates were obtained. These available low mass fractions rule out the possibility of analyzing them using routine procedures at the SARM. These fractions were analyzed for their Ge elemental compositions using a ThermoFischer ICP-MS X-Series at CRPG (Nancy, France) with a 2σ SD of 1.2%.

Ge isotopic measurements

Samples in a 0.5 M HNO 3 solution from the cation exchange step were analyzed for their Ge isotopic compositions using a NeptunePlus multiple-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) at CRPG coupled with a hydride generator introduction system (HGIS). The HGIS method involves mixing the sample with a high-reducing solution of NaBH 4 -NaOH. The reactions between these two solutions convert volatile aqueous species (GeOH 4 ) to gaseous (GeH 4 (gas) ) hydride species [START_REF] Dedina | Hydride generation, atomic absorption spectrometry[END_REF][START_REF] Abdul-Majeed | Computational Modelling of the Hydride Generation Reaction in a Tubular Reactor and Atomization in a Quartz Cell Atomizer[END_REF]. As the reducing solution is in excess, the reaction yield is 100%. This technique removes isobaric interferences from elements that do not form hydrides, avoiding Zn, NiO, and FeO interferences, as well as matrix effects. The result is a gain in signal sensitivity of at least a factor of 30, required for routine isotopic measurements of 10 -20 ng Ge (exceptionally down to 5 ng) to obtain high precision and a good external reproducibility of less than 0.1‰ (2σ SD) (see [START_REF] Rouxel | Germanium Isotope Geochemistry[END_REF] for more details). Data were acquired in static mode using the 68 Zn, 69 Ga, 70 Ge, 71 Ga, 72 Ge, 73 Ge, and 74 Ge isotopes that corresponded to the L3, L2, L1, C, H1, H2, and H3 Faraday cups, respectively. We report an intensity of 1.5 -2.5 V on 74 Ge for a 10 ppb Ge standard solution. Each measurement was composed of a 320 s data acquisition sequence distributed over 40 cycles. Procedural Ge blanks, including chemistry and MC-ICPMS, were better than 70 pg and negligible as this represents less than 0.1% of the 100 ng of Ge processed for each sample. Sample measurements were bracketed using the NIST3120a Ge standard solution. Results are reported in delta (δ) notation using x Ge/ 70 Ge ratios with respect to the mean ratios of the NIST 3120a standard analyzed just before and after the sample [START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF]:

.

(1)

JMC and Aldrich germanium standard solutions were analyzed during the course of the study, yielding δ 74/70 Ge = -0.32 ± 0.11‰ (n = 95) and δ 74/70 Ge = -1.97 ± 0.12‰ (n = 99) (2σ SD), respectively. The BIR-1 basalt geostandard yielded δ 74/70 Ge = 0.63 ± 0.17‰ (n = 10) and the in-house IAB Magura iron meteorite [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF] had a δ 74/70 Ge value of 0.78 ±0.08‰ (n = 19). These values agree with the references given in Luais ( 2012) and [START_REF] Escoube | An Intercomparison Study of the Germanium Isotope Composition of Geological Reference Materials[END_REF].

Results

Elemental composition

The majority of the bulk H OCs displayed a rather uniform Ge concentration, ranging from 10.3 to 22.2 ppm (mean = 15.8 ± 0.8 ppm; see Table 3 and Fig. 1) with no variation among the petrologic types, which is in agreement with [Ge] mean = 12.7 ± 1.5 ppm reported in Fouché and Smales, (1967) and similar to the value reported for L OCs in [START_REF] Tandon | Gallium, germanium, indium and iridium variations in a suite of Lgroup chondrites[END_REF]. [START_REF] Wasson | Compositions of Chondrites[END_REF]. For these samples, this may be due to a sampling bias from either a high taenite zone or, although the main mass may appear to be homogeneous, a small-scale heterogeneous repartition of metal that led to the sampling of a metal-rich zone.

Germanium concentrations in metal ranged from 50 to 83.5 ppm for H chondrites, with a mean of 64.6 ± 17.6 ppm (2σ SD), 104.3 to 157.8 ppm for L chondrites, with a mean of 135.9 ± 53.2 ppm (2σ SD), and 85 to 120 ppm for LL chondrites, with a mean of 102.5 ± 49.5 ppm.

These values are within those reported by Chou et al. (1973) and [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF], who proposed that a significant amount of Ge in the silicates was redistributed in the metal during metamorphism. Moreover, the increase in the oxidation state from H to L to LL should have decreased the amount of the metal phase, and, consequently, increased the concentration of Ge in the metal. Taken together, all the metal samples define a positive correlation among Ge, Ni, and Co, demonstrating that taenite (Ni-rich) is more concentrated in Ge than kamacite (Ni-poor)

(see Figure A in the Appendix).
Germanium concentrations in silicates from the H group ranged from 0.2 (H4 Ste Marguerite) to 2.2 ppm (H3.4 Sharps) (see Table 3 and Fig. 1), identical to the order of magnitude for data reported in Chou et al. (1973). However, we observed a discrepancy for the Allegan Ge concentration between our data, i.e., 0.35 ppm compared with a value of 0.06 ppm reported in Chou et al. (1973). In the L group, Ge concentrations in silicates ranged from 0.05 ppm (L6 Alfianello) to 0.65 ppm (L4 Bjürbole) (Table 3 and Fig. 1). They are identical to the values reported by [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF] The sulfides from H6 Kernouvé and H4 Ste Marguerite were strongly depleted in Ge, with concentrations of 1.75 and 1.95 ppb (see Table 3 and Fig. 1), respectively. This indicates the strong compatibility of Ge in the Fe-Ni metallic phase.

Germanium isotopic data

Germanium isotope measurements were performed on bulk samples, silicates, and sulfides from H group chondrites, whereas we only analyzed L samples for metal and silicate, and LL for metal (Table 3). All samples plot on the mass-dependent fractionation line (see Fig. Bulk Ge isotopic compositions define a narrow range from δ 74/70 Ge = -0.59 ± 0.04‰ to -0.37 ± 0.15‰, with a mean of δ 74/70 Ge = -0.54 ± 0.09‰. Only Dhajala (with the highest δ 74/70 Ge value at -0.37‰) deviated by more than 0.1‰ from the mean. Therefore, this sample ,was not included in the mean (see section 4.5 for explanation) (Fig. 2A).

The δ 74/70 Ge composition for metal from H group samples ranged from -0.33 ± 0.12‰

(Dhajala) to -0.57 ± 0.12‰ (metallic globules from Portales Valley), with a mean of -0.51 ± 0.09‰ (N.B. we excluded the Dhajala value due to its unusual Ge isotopic composition, see section 4.5 for explanation). The δ 74/70 Ge metal compositions for L group samples showed small variations from -0.35 ± 0.09‰ (Hedjaz) to -0.28 ± 0.01‰ (Alfianello), with a mean of δ 74/70 Ge = -0.31 ± 0.06‰. The LL group yielded a mean value of δ 74/70 Ge = -0.26 ± 0.09‰.

Silicates displayed lighter Ge isotopic compositions than bulk samples, with a large range in δ 74/70 Ge from -0.92‰ for Allegan (H5) to -0.50 ± 0.11‰ for Dhajala (H3), with a mean of -0.67 ± 0.33‰ for the H groups (Fig. 2A) and from -1.25 (Alfianello, L6) to -0.50 ± 0.09 (Bjürbole, L4)

with a mean of -0.87 ± 0.18 for the L group (Fig. 3A).

The sulfides were analyzed in two samples, without replicates due to their low abundance in OCs and Ge concentration (≈ 2 ppb). They were characterized by the lightest isotopic values at δ 74/70 Ge = -1.60‰ (Ste Marguerite, H4) and δ 74/70 Ge = -1.56‰ (Kernouvé, H6). We attributed the highest error to these samples based on the standards at ± 0.20‰ (2σ SD) (Fig. 3).

The two chondrule fractions from Dhajala had similar isotopic compositions of δ 74/70 Ge = -0.28 ± 0.12‰ for < 300 µm chondrules and δ 74/70 Ge = -0.38 ± 0.11‰ for > 300 µm chondrules (Table 3).

Metal phases: main contributors to Ge isotopic compositions in bulk OCs

The metal phase is at least 60 times more concentrated in Ge than the silicates (Chou et al., 1973) and four orders of magnitudes higher than sulfide (Fig. 3A). The germanium isotope compositions of bulk H chondrites (mean δ 74/70 Ge bulk = -0.54 ± 0.09‰) were within error of the metal (mean δ 74/70 Ge metal = -0.51 ± 0.09‰), except for Sharps, and higher than the silicate (mean δ 74/70 Ge silicate = -0.67 ± 0.33‰). In a δ 74/70 Ge versus Log(1/Ge) diagram (Fig. 3B), the mixing line defined by the bulk sample, metal, silicate, and sulfide phases (mean δ 74/70 Ge sulfide = -1.56 ± 0.02‰), at all metamorphic grades, indicates that the δ 74/70 Ge measurements of separate phases are consistent with the δ 74/70 Ge measurements of the bulk chondrite. The Ge isotopic fractionation, i.e., Δ 74/70 Ge bulk-metal = δ 74/70 Ge bulk -δ 74/70 Ge metal = -0.03 ± 0.21‰, for the H OC is near zero, compared with Δ 74/70 Ge bulk-silicate = 0.16 ± 0.33‰, Δ 74/70 Ge bulk-sulfide = 1.06 ± 0.16‰, and Δ 74/70 Ge metal-silicate = 0.22 ± 0.36‰ (Table 4; Fig. 4A,B). This indicates that the metal phase was the main contributor to the bulk Ge isotopic budget and that the δ 74/70 Ge metal values are a proxy for the δ 74/70 Ge bulk values.

In addition, we did not observe any correlation between the degree of shock and germanium isotopic composition. For example, Allegan (H5, S1) and Roses city (H5, S6) had identical δ 74/70 Ge bulk isotopic compositions (Table 3).composition.

Discussion

Metal-silicate-sulfide fractionation during condensation

During the cooling of a primordial nebular gas, metal (FeNi) and forsterite (Mg 2 SiO 4 ) condense at similar temperatures, i.e., T 50% condensation = 1370K at 10 -4 atm [START_REF] Yoneda | Condensation of CaOMgOAl2O3SiO2 liquids from cosmic gases[END_REF]. The most abundant gaseous molecular species of germanium are GeS, GeBr 2 , and GeO [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF]. As GeBr 2 is a highly volatile species of Ge, which condenses at much lower temperatures than GeS and GeO [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF][START_REF] Wai | Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites[END_REF][START_REF] Wood | The condensation temperatures of the elements: A reappraisal[END_REF], here, we only discuss GeS and GeO condensation. Condensation of GeS and GeO via reactions with existing silicates and FeNi alloys occur at T 50% condensation = 883K (ideal Ge solution; [START_REF] Lodders | Abundances of the elements in the solar system[END_REF] or T 50% condensation = 825-830K (no ideal solution; [START_REF] Wai | Nebular condensation of moderately volatile elements and their abundances in ordinary chondrites[END_REF][START_REF] Wood | The condensation temperatures of the elements: A reappraisal[END_REF] and pH 2 O/pH 2 = 4.2 * 10 -4 . [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF] showed that Ge is siderophile during high-temperature condensation and becomes lithophile at low temperatures. Thus, germanium condenses first in the metal based on the following reaction [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF][START_REF] Wai | Nebular condensation of Ga, Ge and Sb and the chemical classification of iron meteorites[END_REF]:

GeS (g) + H 2 = Ge (s, in metal) + H 2 S (g) . (2)
Then, at lower temperatures, the remaining Ge is incorporated into the silicate phase according to the following reaction [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF][START_REF] Wai | Nebular condensation of moderately volatile elements and their abundances in ordinary chondrites[END_REF]:

nGeO (g) + 2Mg 2 SiO 4(s) + H 2 O (g) = 2MgSiO 3(s) + Mg 2 (nGe, 1-nSi)O 4(s) + H 2 . (3)
On the other hand, sulfide condenses at lower temperatures than metal and silicate (T 50% condensation = 691K) via reactions between H 2 S gas and solid metal based on the following reaction [START_REF] Lauretta | The origin of sulfide-rimmed metal grains in ordinary chondrites[END_REF], and references therein):

H 2 S (g) + Fe (s) = FeS (s) + H 2(g) . ( 4)

The extent and direction of isotopic fractionation in the solid condensate with respect to the vapor source is difficult to evaluate and depends on whether the system maintains equilibrium, is kinetically controlled, or is in a closed or open system. High-temperature equilibrium processes do not induce significant isotopic fractionation, whereas kinetic condensation can result in isotopic fractionation based on the relative cooling rate of the gas and partial pressure of the relevant elements in the gas [START_REF] Richter | Timescales determining the degree of kinetic isotope fractionation by evaporation and condensation[END_REF]. Calculations from [START_REF] Richter | Timescales determining the degree of kinetic isotope fractionation by evaporation and condensation[END_REF] demonstrate that condensation in an environment, in which the temperature drop is relatively fast compared to the condensation time, results in P i << P i,sat (where P i is the partial pressure of a volatile element and P i,sat is its saturation vapor pressure). In this case, kinetic condensation produces a large isotopic fractionation between the source and condensing phase, where the first condensate is enriched in light isotopes. In the condensation sequence, the metal phase that condenses first has the lightest Ge isotopic composition compared with that of the silicate and sulfide. In contrast, we observed higher δ 74/70 Ge metal values for the metal than for the silicate and the lowest δ 74/70 Ge sulfide values in the H chondrites (Fig. 3A).

We can draw the same conclusion from the sulfide data. Sulfides in equilibrated OCs are depleted in germanium, with a Ge content as low as 2 ppb and light isotopic composition of δ 74/70 Ge = -1.56‰ (Fig. 3A). As the first Ge condensates are incorporated into the Fe-Ni alloys, the late sulfide condensate result in (i) a low Ge content (as observed here), despite the fact that Ge is a chalcophile element (Chou et al., 1973), and (ii) a heavier Ge isotopic composition for the sulfides as compared with the metal [START_REF] Davis | 1.10 -Condensation and Evaporation of Solar System Materials[END_REF]. The lighter δ 74/70 Ge sulfide values compared with the δ 74/70 Ge metal values, however, rules out condensation from a protoplanetary disk as a viable process for the origin of Ge isotopic fractionation in metalsilicates and sulfides in ordinary chondrites.

Evidence for metal-silicate-sulfide partial equilibration before OC accretion

Germanium isotopic compositions in metal, silicate, and sulfide phases in all samples of the H chondrites display the following relationship: δ 74/70 Ge sulfide << δ 74/70 Ge silicate < δ 74/70 Ge meta (Fig. 3A). This relationship holds even for the most reduced type 3 samples, which are the least affected by thermal metamorphism at T<675°C [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF], which is too low to melt metal or silicate. This observation suggests that the positive Δ 74/70 Ge metal-silicate = +0.22 ± 0.36‰ (varying from +0.17 to +0.33‰ in H3) values is due to metal-silicate exchange that occurred before the accretion of H ordinary chondrite parent body. This positive Δ 74/70 Ge metal-silicate also occurs between the Earth silicate reservoir (δ 74/70 Ge = +0.56 ± 0.16‰) and magmatic Fe-meteorites (δ 74/70 Ge = +1.41 ± 0.22‰) [START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF], which may represent the core of early formed planetesimals. Therefore, higher δ 74/70 Ge values in metal compared to silicate, in both undifferentiated and differentiated bodies, appears to be the result of metal-silicate equilibrium.

The larger Δ 74/70 Ge metal-silicate of +0.85‰ in differentiated bodies reservoirs (e.g. the silicate Earth and Fe-meteorites, Luais, 2012) compared to Δ 74/70 Ge metal-silicate in OCs can reflect additional isotopic fractionation during core-mantle differentiation.

The addition of sulfur in the Fe-Ni system strongly modifies the Ge incorporation into the metal phase. Chabot et al. (2003) and Chabot and Jones (2003) demonstrated that, during fractional crystallization at FeNi-S metallic liquid equilibrium, the D(Ge) solid metal/liquid metal value increases by several orders of magnitude as S increases in the liquid. Similar low Ge contents have also been observed in S-rich melts during Fe-Ni-S partial melting experiments [START_REF] Rushmer | Fe-liquid segregation in deforming planetesimals: Coupling Core-Forming compositions with transport phenomena[END_REF]. Low Ge contents (2 ppb) in sulfide from type 4 and 6 OCs (Fig. 3A) likely result from late-stage fractional crystallization of Fe-Ni-S melts. The strongly negative δ 74/70 Ge sulfide value of -1.56‰ appears to be a feature common to sulfides formed by fractional crystallization, such as terrestrial sulfides [START_REF] Belissont | LA-ICP-MS analyses of minor and trace elements and bulk Ge isotopes in zoned Ge-rich sphalerites from the Noailhac -Saint-Salvy deposit (France): Insights into incorporation mechanisms and ore deposition processes[END_REF]. As we have no isotopic values for the H3 type, it is unclear if sulfide crystallization occurs during nebular processes or on the parent body.

However, the discrepancy between temperatures associated with the H4 petrologic type (676-865°C; [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF] and FeNi-S fusion temperature (963°C; [START_REF] Mare | Restriction of parent body heating by metal-troilite melting: Thermal models for the ordinary chondrites[END_REF] suggest that negative Ge isotopic composition of sulfides could have been inherited from processes that occur before parent body accretion, as it has been proposed for metal and silicate phases.

Equilibrium among metal, silicate, and sulfide in ordinary chondrites must then reflect processes before the accretion, such as (1) partial re-equilibration of material produced by disruption of partially differentiated planetesimals, or (2) a heating event in the solar nebula. isotope evaporation due to the pressure (e.g., Roses City, H5), or an increase in temperature during a low energetic impact, which may be not sufficient to efficiently evaporate Ge.

Effects of metamorphism

Unequilibrated OCs (type 3) are primitive and may correspond to the outer layer of a layered planetesimal [START_REF] Trieloff | Structure and thermal history of the H-chondrite parent asteroid revealed by thermochronometry[END_REF] that experienced low-temperature metamorphic processes (< 675°C; [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF]. They represent the most reduced type of each OC group [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF]. This implies that metal-silicate exchange is limited compared to other petrologic types and that younger processes may not have overprinted isotopic fractionation, which had been established before planetesimal accretion [START_REF] Van Schmus | A chemical-petrologic classification for the chondritic meteorites[END_REF].

From the H3 to H5 petrologic types, certain variations in the Δ 74/70 Ge metal-silicate values (Fig. 4B) indicate Ge isotopic exchange between metal and silicate during thermal metamorphism.

However, the lack of variation in the δ 74/70 Ge metal values suggests that metamorphism had no measurable effect on the Ge isotopic composition of the metal phase. Thus, variations in the Δ 74/70 Ge metal-silicate values (Fig. 4B) indicate an increased sensitivity to δ 74/70 Ge silicate during metamorphic processes due to the lower Ge content in the silicate compared to the metal.

Melting points for the FeNi-S assemblage and silicate are 963°C and 1050°C, respectively, at 0.3 kBar (Mare et al., 2014 and references therein). Types 3 to 5 OCs experienced different peak metamorphism temperatures from T < 675°C for H3, 525-727°C for H4, and 676°C < T < 865°C for H5 [START_REF] Monnereau | Thermal history of the H-chondrite parent body: Implications for metamorphic grade and accretionary time-scales[END_REF][START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF]. These temperature ranges are likely too low to melt FeNi-S alloy and cause metal-silicate exchange. In contrast, type 6 OCs reached temperatures between 866°C and 1000°C [START_REF] Monnereau | Thermal history of the H-chondrite parent body: Implications for metamorphic grade and accretionary time-scales[END_REF][START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF]. FeNi-S melting and efficient Ge silicate-metal exchange resulted in an increase in the Ge content for metals from the H3-H5 types ([Ge] mean = 61.9 ppm), excluding Allegan (see section 3.1), to the H6 type ([Ge] mean = 66.0 ppm), which agrees with Ge diffusion from silicate to metal during metamorphism (Chou et al., 1973). Similarly, Ge isotopic exchange between metal and silicate in H6 resulted in a heavier silicate isotopic composition, which approached the isotopic composition of the metal. This led to a similar Ge isotopic composition for the silicate, metal, and bulk in the H6 chondrites within the 2σ error range (Fig. 4A,B).

The global scheme for L chondrites is not as clear as it is for H chondrites. Except for the Bjürbole sample (L4 at -0.5‰), silicates from the L6 chondrites have negative and heterogeneous δ 74/70 Ge values that are distinct from the metal phase values (Figure 3A), which suggest that there was no isotopic re-equilibration, such as that observed in H6 chondrites. The "onion shell" model is less constrained for L chondrites. [START_REF] Göpel | U/Pb systematics of phosphates from equilibrated ordinary chondrites[END_REF] proposed that the L parent body formed from thermal gradient disruption due to impact processes and reassembly. If this had occurred before metal-silicate equilibration, this could have prevented the efficient Ge exchange between the metal and silicate. Finally, the isotopic uniformity of the metal phases from H3 to H6 and L3 to L6 (Figure 2B) are consistent with closed-system metamorphism within each parent body.

4.4. Links between the redox process and δ 74/70 Ge variations throughout the H-L-LL sequence

The main characteristic of ordinary chondrites is their increase in oxidation state through the H, L, and LL sequences, which is inferred from the decrease in metal content and increase in the percentage of fayalite in olivine (Chou et al., 1973). The similar increase in the δ 18 O composition and Δ 17 O anomalies from the H to LL OCs [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] led [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF] to identify a correlation between the % Fa in olivine and the δ 18 O and Δ 17 O values.

The Ge concentration and isotopic composition in metal increases from the H to L to LL groups (Fig. 2B), which discounts the occurrence of any Ge loss and evaporative processes during OC formation. A well-defined positive correlation was identified among the %Fa, Ge concentrations, and δ 74/70 Ge in metal for all petrographic types and groups (Fig. 5A andB). At first glance, this suggests that the metal becomes enriched in Ge and the heavy isotopes of Ge with increasing oxidation. However, as the D(Ge) value decreases with an increasing fO 2 [START_REF] Kegler | Determination of the formal Ge-oxide species in silicate melts at oxygen fugacities applicable to terrestrial core formation scenarios[END_REF], we can expect the metal in the L chondrites to become depleted in Ge compared to the metal in H chondrites, whereas we observe the opposite (Fig. 5). Therefore, oxidation is not the main process that causes an increase in Ge content from H to LL. In the Urey and Craig-type diagram, i.e., Fe metal + sulfide vs FeO [START_REF] Krot | Classification of meteorites and their genetic relationships[END_REF], variations in reduced Fe and FeO do not follow the reduction-oxidation trend, suggesting that the system has lost some of its iron metal. In this case, the increase in the Ge content for the metal from H to LL, with a broadly constant Ge bulk concentration [START_REF] Wasson | Compositions of Chondrites[END_REF], can be explained by the incorporation of Ge into the remaining metal. However, this process cannot explain the increase in the δ 74/70 Ge throughout the OC sequence. In conclusion, the increases in Ge, δ 74/70 Ge, and %Fa are not related to oxidation conditions in the environment of OC formation, i.e., the fO 2 conditions. One explanation may be the involvement of an oxidizing component

The δ 74/70 Ge values and δ 18 O and Δ 17 O are also characterized by a positive correlation (Fig. 6) in which these three groups are distinguishable outside of the analytical errors, with the following values for H (mean Δ 17 O = 0.71 ± 0.12‰ and δ 74/70 Ge = -0.51 ± 0.09‰), L (mean Δ 17 O = 1.02 ± 0.15‰ and δ 74/70 Ge = -0.31 ± 0.06‰), and LL chondrites (mean Δ 17 O = 1.18 ± 0.12‰ and δ 74/70 Ge = -0.26 ± 0.09‰). As metamorphism does not modify δ 74/70 Ge in metal and bulk chondrite, we suggest that Ge isotopic variations among the three groups are the result of accretionary processes. Hence, correlations among >Ge@-δ 74/70 Ge-%Fa, δ 18 O, and Δ 17 O reflect processes that originated in the accretionary disk, which were broadly linked to the redox state.

Specifically, chondrule mixing of type I-reduced and type II metal-free chondrules [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF][START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF], as well as the incorporation of an oxidizing component during OC accretion [START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF] were the two main processes (see discussion below).

4.4.1. Chondrules as carriers of a high δ 74/70 Ge signature? [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] demonstrated that, in certain ordinary chondrites, small-size chondrules (with diameter d < 300 µm) show enrichment in 16 O and depletion in 17 O compared with larger chondrules (d > 300 µm). This difference has been interpreted in terms of the interaction between 16 O-poor melted chondrules and 16 O-rich gas at their time of formation.

Chondrules were then classified into type I chondrules (magnesian), which are small, reduced, metal-rich, and depleted in volatiles, and type II chondrules (ferroan), which are larger, oxidized, metal-free, and volatile-rich (Zanda, 2004;[START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF]. Additionally, [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF] showed that the proportions of the type I chondrule decrease through the OC sequence while type II increases (type I: 45%, 28%, and 22%; type II: 36%, 58%, and 61% in the H, L, and LL groups, respectively). Based on the sizes of type I and II chondrules, their volume in the H, L, and LL OCs, and the oxygen isotopic compositions of large chondrules (heaviest) compared to small chondrules, [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] argues that the increase in Δ 17 O through the H-L-LL sequence can be explained by a "size-sorting process" of chondrules, whereas [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF] argue for mixing between petrological components of the chondrites. Thus, considering the δ 74/70 Ge-δ 18 O-Δ 17 O correlations (Fig. 6 and 7), we can assess if type II chondrules have a heavier δ 74/70 Ge composition compared with type I chondrules. An increase in type II can elevate the δ 74/70 Ge ratio in type II rich-ordinary chondrites.

We used two approaches to test the chondrule mixing hypothesis. First, we calculated the inferred δ 74/70 Ge composition of type I and type II chondrules, as well as the matrix, to account for variations in δ 74/70 Ge from H to LL due to mixing between these components (Fig. 7A). This mass balance calculation is based on [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF], with type I and II chondrules, the matrix proportions in H, L, and LL, and their respective oxygen isotopic compositions (see the caption for Fig. 7 for more details and Table 2 in [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF]. Based on this modeling, we obtained the following theoretical compositions: δ 74/70 Ge type I = -0.81‰, δ 74/70 Ge type II = 2.15‰, and δ 74/70 Ge matrix = -7.35‰.

For the second approach, we analyzed the Ge isotopic composition of type I and II chondrules. As it is not possible to distinguish between type I and II chondrules at the macroscopic scale, we used the same protocol as [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] on the same meteorite (Dhajala H3.8). We separated two chondrule fractions (i.e., d < 300 and d > 300 µm) based on the assumption that the smaller fraction should be mainly composed of type I chondrules while the larger fraction contains type II chondrules. Our results on the chondrule fractions show that the δ 74/70 Ge values of small (δ 74/70 Ge d<300µm = -0.28 ± 0.12‰) and large chondrules (δ 74/70 Ge d>300µm = -0.38 ± 0.11‰) (Table 3) are similar within error and are near the Dhajala bulk value (δ 74/70 Ge = -0.37 ± 015‰). In the δ 74/70 Ge-δ 18 O diagram, the graphic, Dhajala bulk chondrite plots on the mixing line defined by type I and II Dhajala chondrules, indicating no analytical artefact. However, type I and II chondrule isotopic compositions do not plot on the δ 74/70 Ge-δ 18 O OC mixing line (Fig. 7B) and do not agree with the calculated values for type I and II chondrules. This precludes any mixing process between type I and II chondrules that can explain the H, L, and LL correlation.

An in-situ ion probe study of oxygen isotopes in individual olivine and pyroxene phases of OC chondrules yielded a more complex picture. Variable δ 18 O but similar Δ 17 O values have been found in type I and II chondrules from H chondrites, as well as the Semarkona (LL3) chondrite [START_REF] Kita | High precision SIMS oxygen three isotope study of chondrules in LL3 chondrites: Role of ambient gas during chondrule formation[END_REF] The main issue with the correlation between Ge elemental/isotopic variations in ordinary chondrites and %Fa in olivine, as well as between δ 18 O and the Δ 17 O, is the origin of oxidation and how it relates to asteroidal processes and/or a nebular origin. [START_REF] Clayton | Formation of ureilites by nebular processes[END_REF] Such asteroidal alteration was responsible for the formation of magnetite via FeNi alloy oxidation [START_REF] Wasson | Fayalite-silica association in unequilibrated ordinary chondrites: Evidence for aqueous alteration on a parent body[END_REF][START_REF] Krot | Carbide-magnetite assemblages in type-3 ordinary chondrites[END_REF][START_REF] Choi | Extreme oxygen-isotope compositions in magnetite from unequilibrated ordinary chondrites[END_REF], the growth of fayalite rims on pyroxene grains via reactions between oxidized Fe and silica [START_REF] Wasson | Fayalite-silica association in unequilibrated ordinary chondrites: Evidence for aqueous alteration on a parent body[END_REF], and the accreted phyllosilicate is needed to change the composition from H to LL chondrites in terms of Ge content and δ 74/70 Ge in phyllosilicate. To constrain the model, we have considered the amount of accreted phyllosilicate, which cannot be higher than the amount of matrix (<15%, [START_REF] Krot | Classification of meteorites and their genetic relationships[END_REF], and the Ge content in terrestrial phyllosilicates. This value ranges between 1.1 -8.5 ppm with means of 3.8 ± 3.2 ppm (2σ SD, calculated from Bernstein, 1985, and references therein). The model shows that at Ge content of 3.8 ± 3. to 7 ppm for 15% and 10% of phyllosilicate, respectively. So, it seems possible that phyllosilicates could contain between 4 to 7 ppm of Ge with a composition of δ 74/70 Ge ≈ +3 to +2.5‰. It can be noted that a Ge content in phyllosilicates of few ppm is likely from the thermodynamic calculation [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF]. They predict that a significant proportion of Ge (in the form of GeBr 2 ) would remain in the gas even after troilite condensation and that Ge would become lithophile at the end of the condensation sequence [START_REF] Sears | Condensation and the composition of iron meteorites[END_REF].

During planetesimal heating, the dehydration of accreted phyllosilicates triggers a redox reaction on the parent body. The release of 18 O-rich and δ 74/70 Ge-high water (or vapor) oxidizes the Fe-Ni metal as FeO, forming magnetite, which then increases the %Fa in olivine.

Germanium released in water is likely incorporated in the metal due to its siderophile behavior.

However, the small amount of Ge does not contribute to the significant increase in Ge from the H to L to LL OCs. In contrast, the high δ 74/70 Ge composition of the released H 2 O component that reacted with the metal should have significantly increased the δ 74/70 Ge metal proportional to the amount of accreted oxidizing agent on each OC parent body. As such interaction may occur during metamorphism, a correlation for the δ 74/70 Ge metal composition is possible for types 3 to 6 in a given OC group. However, we propose that the lack of a δ 74/70 Ge metal correlation with the petrologic type is imputable to the relatively high temperature of thermal metamorphism, which is even recorded in the earlier stage of pervasive H 2 O alteration via magnetite formation in the type 3 chondrite (T < 675°C) [START_REF] Krot | Carbide-magnetite assemblages in type-3 ordinary chondrites[END_REF][START_REF] Choi | Extreme oxygen-isotope compositions in magnetite from unequilibrated ordinary chondrites[END_REF][START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF]. The fractionation of stable isotopes at equilibrium is a function of 1/T 2 , such that an increase in the metamorphic temperature from types 3 to 6 (T < 675 to 975°C, [START_REF] Tait | Investigation of the H7 ordinary chondrite, Watson 012: Implications for recognition and classification of Type 7 meteorites[END_REF] does not induce significant variations in the Ge isotopic fractionation between the H 2 O-component and metal with the petrologic type. Hence, the observed Ge isotopic fractionation among groups is primarily a function of the amount of nebular hydrated phyllosilicate with a high δ 74/70 Ge signature accreted onto the parent body. The heavy O isotopic composition of OCs that partly derive from phyllosilicate destabilization can be considered, along with the previous H 2 O gas or ice model for the origin of accreted water.

Dhajala: A reduced L chondrite

The higher δ 74/70 Ge metal composition of Dhajala (H3.8) compared with the other H chondrites, including Sharps (H3.4), which has a similar petrologic type, requires discussion because Dhajala does not fit the correlations shown in Figs. 5B and6. Dhajala and Sharps have both experienced a low degree of metamorphism. They lie within the oxygen isotope field as H chondrites but Dhajala (H3.8) has oxygen isotopic anomalies that are slightly higher than Sharps (H3.4) (Δ 17 O Dhajala = 0.698 ‰and Δ 17 O Sharps = 0.646 ‰; [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF]. The high Fe metal (15.98 wt. %), and low FeO bulk (10.18 wt. % ) contents in Dhajala compared with Sharps (Fe metal = 12.02 wt. % and; FeO bulk = 13.64 wt. %) (Table 5) reflect more reduced conditions for Dhajala than for Sharps. In contrast, the high percentage of fayalite and low carbon content in Dhajala (%Fa = 19.3; C = 0.04 wt. %) indicate more oxidized conditions than for Sharps (%Fa = 17.5 and C = 0.95 wt. 95 wt. %) [START_REF] Jarosewich | Chemical analyses of meteorites: A compilation of stony and iron meteorites analyses[END_REF]. In addition, the Dhajala germanium isotopic composition is closer to L type composition than H type (Figs. 2 and6). Thus, we propose that Dhajala accreted identical proportions of oxidizing component than L chondrites, which led to olivine formation with high %Fa (> 20) and an increase in the δ 74/70 Ge metal composition that approaches the L Ge isotopic signature. Dhajala then experienced reduction by carbon [START_REF] Mcsween | Oxidation during metamorphism of the ordinary chondrites[END_REF] based on the following reaction [START_REF] Warren | Ureilite petrogenesis: A limited role for smelting during anatexis and catastrophic disruption[END_REF]:

C + MgFeSiO 4 = MgSiO 3 + Fe + CO. (5)
In conclusion, the elevated δ 74/70 Ge metal composition in Dhajala with low %Fa is the result of high carbon activity in this meteorite, which did not decrease due to C dissolution in taenite [START_REF] Romig | Determination of the Fe-rich portion of the Fe-Ni-C phase diagram[END_REF] by contrast with Sharps. This implies that Dhajala most likely formed in the L region of the accretionary disk before reduction via carbon. This suggests that the OC accretion environment is heterogeneous and δ 74/70 Ge should be considered a tracer of the primary locations that formed undifferentiated meteorites.

4.6. Relationship between the OC redox state and IIE iron meteorites IIE non-magmatic iron meteorites formed by impact-induced melting and the destruction of a chondritic parent body, followed by metal silicate re-accretion [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF][START_REF] Ruzicka | Silicate-bearing iron meteorites and their implications for the evolution of asteroidal parent bodies[END_REF][START_REF] Wasson | A nonmagmatic origin of group-IIE iron meteorites[END_REF]. This group can be divided into old (Miles, Weekeroo Station) and young groups (Netschaëvo, Watson), which formed from 4.3 -4.5 and 3.5 -3.8 Ga, respectively [START_REF] Bogard | Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution[END_REF]. They have a complex mineralogy, mainly composed of metal and silicate inclusions. These inclusions represent 5 to 10 vol. % of the IIE meteorites and are composed of silicates (feldspar, pyroxene, and olivine) phosphates, sulfides, and chromite [START_REF] Mcdermott | Oxygen isotope and petrological study of silicate inclusions in IIE iron meteorites and their relationship with H chondrites[END_REF]. Silicate inclusions can be classified into two categories, chondritic inclusions with relic chondrules and differentiated inclusions [START_REF] Mcdermott | Oxygen isotope and petrological study of silicate inclusions in IIE iron meteorites and their relationship with H chondrites[END_REF].

The genetic links between the H OC and IIE iron meteorites were first identified based on the similar elemental and oxygen isotopic compositions of silicate inclusions from IIE iron and silicates from the H OC [START_REF] Olsen | Chondrules: First Occurrence in an Iron Meteorite[END_REF][START_REF] Clayton | Oxygen isotope studies of achondrites[END_REF]. However, based on the (1) concentrations in the refractory and volatile siderophile elements and (2) low

Δ 17 O values in silicate inclusions in the IIE Netschaevo meteorite, we can infer that the impact, which formed the IIE iron meteorites, occurred on an HH parent body that was more reduced than the H group [START_REF] Mcdermott | Oxygen isotope and petrological study of silicate inclusions in IIE iron meteorites and their relationship with H chondrites[END_REF][START_REF] Wasson | Formation of non-magmatic iron-meteorite group IIE[END_REF].

To study the genetic link between the IIE irons and OCs, we only must consider meteorite samples from the IIE old group because they display the most pristine δ 74/70 Ge metal compositions compared with the young group, which show an increase in δ 74/70 Ge metal due to successive impacts [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF]. Figure 9 shows the positive correlation among the δ 74/70 Ge composition of IIE bulk metal [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF][START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF], OC metal (data from this study), and Δ 17 O measured in silicate inclusions from IIE irons and bulk silicates from the H, L, and LL OCs (see

Summary

We report the first data set of germanium isotopic compositions for bulk and separated phases from ordinary chondrites. The Germanium isotopic compositions were measured by an MC-ICP-MS coupled to a hydride generator system with a 2σ long term reproducibility of 0.1‰.

We found that the Ge isotopic composition of ordinary chondrites is mainly driven by the metal phase, which is a good proxy for the OC bulk composition. The δ 74/70 Ge metal values significantly increased throughout the OC sequence, such that H, L, and LL groups are distinguishable at -0.51 ± 0.09‰, -0.31 ± 0.09‰, and -0.26 ± 0.09‰, respectively. The implications of the germanium isotopic compositions for the understanding of ordinary chondrite compositions can be summarized as follows.

x The lack of significant δ 74/70 Ge metal variation between the unequilibrated and equilibrated

OCs within each group implies that δ 74/70 Ge variation among groups is inherited from nebular processes rather than parent body processes.

x Metal and silicate are partially equilibrated in a closed system during metamorphism.

x The positive Δ 74/70 Ge metal-silicate signature is remarkably similar to previously reported Ge isotopic fractionations between magmatic iron meteorites and Earth silicates. However, the light δ 74/70 Ge composition of both metal and silicate suggests that metal, silicate, and sulfide have interacted before the accretion of ordinary chondrite parent bodies in a gas enriched in light Ge isotopes.

x The two well-defined positive correlations between δ 74/70 Ge metal and %Fa, as well as x The δ 74/70 Ge metal -Δ 17 O silicate correlation in the OCs provides evidence for the existence of an HH reduced parent body and its genetic link with the IIE iron meteorites. was not included in the mean value for H due to its off-trend isotopic composition (see section 4.5 for more details). Identical abbreviations as Fig. 1 and Table 1. (A) Correlation between Δ 74/70 Gemetal-silicate and Δ 74/70 GeBulk-silicate with a slope of 1.2 (R² = 0.9). Metal and bulk Ge isotopic compositions are similar within a 2σ SD. (B) Δ 74/70 Gemetal-silicate versus δ 74/70 Gemetal shows no isotopic variation for metals among the petrologic groups. Values are from Table 4. Both the H and L groups plot near the regression line, where no clear correlation occurs within the groups. There is no data for %Fa for Parnalle due to its large range in olivine composition (e.g., [START_REF] Rubin | Kamacite and olivine in ordinary chondrites: Intergroup and intragroup relationships[END_REF]. Ge data for LL for Sako-Banja (SB), Cherokee Spring (CS), Olivenza, (Olz), Paragould (Prg), Dhurmsala (Drm), and Mangwendi (Mgw) are from [START_REF] Chou | Gallium and germanium in the metal and silicates of L-and LLchondrites[END_REF] and %Fa data are from [START_REF] Dodd | Recrystallized chondrules in the Sharps (H-3) chondrite[END_REF] and [START_REF] Dunn | A coordinated spectral, mineralogical, and compositional study of ordinary chondrites[END_REF]. See Table 5 for other references and %Fa. 5.

Δ

Figure 7:

(A) Germanium isotopic compositions versus oxygen isotopic compositions for the two chondrule fractions from Dhajala (< 300 μm are filled blue diamonds and > 300 μm are empty blue diamond). The x-axis oxygen isotopic compositions for the < 300 μm and > 300 μm size fraction chondrules are the variations reported in [START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF]. Blue, red, and green circles represent averages of the germanium and oxygen isotopic compositions for the H, L, and LL groups, respectively. Oxygen isotopic compositions and references are given in Table 5. (B) Theoretical Type I and II chondrules and matrix germanium isotopic composition based on chondrules and matrix mixing calculations. All data for the chondrules, matrix proportions (type I = 45%, 28 % and 22%; type II = 36%, 58%, and 61%; matrix = 12.4%, 10.2%, and 15.4%, for H, L, and LL, respectively), and their respective oxygen isotopic compositions are from [START_REF] Zanda | Formation of solar nebula reservoirs by mixing chondritic components[END_REF]. The calculated Ge isotopic compositions of δ 74/70 Getype I = -0.81‰, δ 74/70 Getype II = +2.15‰, and δ 74/70 Gematrix = -7.35‰ do not agree with the measurements of δ 74/70 Ge in chondrules displayed in Figure 7A. . The forbidden zone can be defined beyond the maximum percentage of matrix in ordinary (15%; [START_REF] Krot | Classification of meteorites and their genetic relationships[END_REF] and maximum Ge content in terrestrial phyllosilicatse (up to 8.5 ppm; [START_REF] Bernstein | Germanium geochemistry and mineralogy[END_REF]. for the LL chondrites (green square). References for the oxygen isotopic compositions are given in Table 5. The Ge isotopic composition of the IIE iron meteorites are from [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF][START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF]. (1) Dhajala was excluded from the mean due to its unusual Ge isotopic composition, see section 4.3 for explanations. (2) There is no standard deviation for sulfide because only one measurement was done per sample due to their low concentration.

  However, Allegan H5 ([Ge] = 22.2 ppm, [Ni] = 1.52 wt. %) and Guareña ([Ge] = 21.4 ppm, [Ni] = 1.59 wt. %) had slightly higher Ge and Ni contents (see Fig. A2 in the Appendix) compared to the OC mean ([Ge] = 15.8 ± 0.8, [Ni] mean = 1.28 ± 0.54 wt. %) and bulk data reported by (Wasson

  first identified the correlations between %Fa in olivine and δ 18 O and Δ 17 O in Urelites. They interpreted these correlations to be associated with oxidation processes in the nebula. Similarly,[START_REF] Rubin | Relationships among intrinsic properties of ordinary chondrites: Oxidation state, bulk chemistry, oxygen-isotopic composition, petrologic type, and chondrule size[END_REF] highlighted the Δ 17 O-%Fa positive correlation among OC groups, suggesting that the increase in the oxidation state through the OC sequence is related to an increase in the proportion of an accreted oxidizing agent with high δ 17 O, δ 18 O, and Δ 17 O signatures. Choi et al. (1998) identified such elevated oxygen isotopic signatures in magnetite from unequilibrated LL OCs, which show a large and unusual deviation from the Terrestrial Fractionation Line (TFL; Δ 17 O ≈ 5‰) compared with OCs that have typical values (Δ 17 O ≈ 0 to 2‰). Choi et al. (1998) suggested that high 18 O-nebular water (δ 18 O = 21‰ and Δ 17 O ≈ 7‰) accreted onto the OC parent body and induced low-temperature aqueous alteration.

  Figure 6, we find that the δ 74/70 Ge = 3.2 -6‰ in phyllosilicates would correspond to a Δ 17 O ≈ +8 to +15‰. The lower Δ 17 O is close to the value of the oxidized nebular component incorporated in OC parent bodies reported by Choi et al. (1998) (Δ 17 O ≈ +7‰), yet a better match is attained for a δ 74/70 Ge = +2.5‰ (Δ 17 O = +7‰) in phyllosilicates. This value implies a Ge content of about 4.8

  17 O, demonstrate that the Ge isotopic composition can be used as a tracer of oxidizing processes during accretion. The similar Ge isotopic compositions of small and large chondrules (from Dhajala) indicate that the size sorting chondrule mechanism cannot account for the δ 74/70 Ge metal -%Fa and Δ 17 O correlations. Therefore, these correlations can be explained by an increase in the amount of accreted high Δ 17 O hydrated nebular phyllosilicates with high δ 74/70 Ge of about 2.5 to 3 ‰, throughout the ordinary chondrite sequence. We can reconsider the origin of the heavy O isotopic signature in ordinary chondrites to derive from either H 2 O (water) or hydrated silicate.

Figure 1 :

 1 Figure 1: (A) Elemental compositions of the bulk meteorites (filled circles), metal (diamond), silicate (empty circle), and sulfide (square) from H (in blue), L (in red), and LL (in green) ordinary chondrites. Data shows large variation among all phases. The germanium concentration decreases from the metal (60 to 170 ppm as a function of the chondrite group) to bulk (≈10 to 20 ppm) to silicate (≈0.1 to 1 ppm) to sulfide (≈2 ppb) phases. There is no variation associated with the petrologic type. (B) A detailed view, in log scale, of the low Ge silicates and sulfide phases (dashed rectangle of A). Table 1 lists all abbreviations.

Figure 2 :

 2 Figure 2: (A) A detailed view of the δ 74/70 Ge isotopic compositions among the bulk, metal, and silicate in the H ordinary chondrites. The meteorites are ordered from the least metamorphosed (Dhajala H3.4) to highest (Guareña H6) types. Rose City and Portales Valley are plotted separately due to their specific textures (see text). The δ 74/70 Ge compositions become lighter from metal, to bulk sample, and, finally, to silicate. Silicates display larger δ 74/70 Ge variations than the metal and bulk samples. Isotopic fractionation between the phases are: Δ 74/70 Gebulk-metal= -0.03 ± 0.21‰, Δ 74/70 Gebulk-silicate = 0.16 ± 0.33‰, Δ 74/70 Gebulk-sulfide = 1.06 ± 0.16‰, and Δmetalsilicate 74/70 Ge = 0.22 ± 0.36‰. (B) A comparison of the δ 74/70 Ge metal values between the H (blue diamonds), L (red diamonds), and LL (green diamond) groups. All meteorites from the H and L and LL groups are plotted, with mean values of Hmean= -0.51 ± 0.09‰, Lmean = -0.31 ± 0.06‰, and LLmean = -0.26 ± 0.09‰. The value for Dhajala

Figure 3 :

 3 Figure 3: (A) δ 74/70 Ge versus log(Ge) concentration of the bulk and mineral phases of the H, L, and LL ordinary chondrites. (B) Negative correlation between δ 74/70 Ge and log(1/[Ge]) for the metal, silicate, bulk sample, and sulfide phases in the H chondrites (R² = 0.85).

Figure 4 :

 4 Figure 4: Variations in the germanium isotopic composition and isotopic fractionation for H ordinary chondrites.

Figure 5 :

 5 Figure 5: (A) The Ge elemental composition versus %Fa in olivine for the three OC groups. All data plot near the regression line (R² = 0.92). (B) δ 74/70 Ge of the metal phase versus %Fa in olivine for the H, L, and LL groups.

Figure 6 :

 6 Figure 6: δ 74/70 Ge of the metal phase versus Δ 17 O of the bulk sample for type 3 to 6 ordinary chondrites. Δ 17 O values are from[START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF]. Rectangles in color represent fields of Δ 17 O variations (1σ SD) calculated from data reported in[START_REF] Clayton | Oxygen isotope studies of ordinary chondrites[END_REF] and δ 74/70 Ge variations (2σ SD). Note that Dhajala value was not included in the H mean because due to its special isotopic composition (see section 4.5 for more details). The dotted line is a linear regression calculated for all individual values (R² = 0.676). %Fa, Δ 17 O data, and references are given in Table5.

Figure 8 :

 8 Figure 8: Modelling of the Germanium content (ppm) in phyllosilicate required to change the germanium isotopic composition from an H (-0.51‰) to LL chondrite composition (-0.26‰) as a function of the accreted amount of phyllosilicates and their δ 74/70 Gephyllosilicate composition at 1‰, 2‰, 3‰, 4‰, 5‰, 10‰, 15‰, and 20‰. The blue dashed line corresponds to δ 74/70 Gephyllosilicate = +2.5‰, representing the isocurve that matches the Δ 17 O of ≈+7‰ reported in Choi et al. (1998) (see text). The horizontal dark blue line is the mean Ge content in terrestrial phyllosilicates (3.8 ppm; Bernstein, 1985, and references therein) and the dark blue zone is the 2σ SD of the mean. The highlighted area in black represents the likely composition of the phyllosilicates (see the text for more

Figure 9 :

 9 Figure 9: Δ 17 O of silicates (bulk ordinary chondrites and silicate inclusions of IIE iron meteorites) versus δ 74/70 Ge of the metal phase in ordinary chondrites and IIE iron meteorites. The positive correlation between the IIE iron meteorites and LL ordinary chondrites demonstrates that the IIE parent body could have formed on a distinct and more reduced parent body than the H ordinary chondrite body, known as the HH parent body. As the Δ 17 O of the NWA-118 sample is low compared to other LL chondrites, we also report the mean δ 74/70 Ge versus Δ 17 O

Figure 2 ,Figure2Figure 3 ,Figure3Figure 4 ,

 234 Figure 2, Florin et al., 2019

Figure 4 Figure 5 ,Figure5Figure 6 ,Figure 6 Figure 7 ,Figure7Figure 8 ,Figure8Figure 9 ,

 4566789 Figure 4

  , and Ge concentrations, as well as the δ 72/70 Ge, δ 73/70 Ge, and δ 74/70 Ge values of the ordinary chondrites relative to NIST 3120a. Reproducibility is given as 2SD. N is the number of replicates for δ 72/70 Ge, δ 73/70 Ge, and δ 74/70 Ge. Error of less than 5% for the Ge, Ni, and Co elemental compositions.

  [START_REF] Bischoff | Brecciation among 2280 ordinary chondrites -Constraints on the evolution of their parent bodies[END_REF] reported that, in more than 2280 polished OC thin sections, there was a high abundance of brecciated rocks and occurrences of xenolithic fragments (e.g., CI, CM, and Ureilite) in type 3 OCs. This supports the hypothesis that OCs can represent aggregates of early formed achondritic, chondritic, and chondrule materials.[START_REF] Lichtenberg | Impact splash chondrule formation during planetesimal recycling[END_REF] argued that OC parent bodies can form from early impact on a preheated (i.e.,26 Al decay) and partially differentiated planetesimal[START_REF] Bryson | Paleomagnetic evidence for a partially differentiated ordinary chondrite parent asteroid[END_REF]. Thus, the negative δ 74/70 Ge values of the bulk sample and all separated OC phases, compared with positive values for magmatic iron meteorites and Earth silicate reservoirs, imply a light isotope-enriched environment for OC formation, i.e., an impact plume environment. Evaporation processes that occur during an impact would likely overprint any Δ 74/70 Ge metal-silicate signature from a previous generation of planetesimals. Metal, metal-silicate, and sulfide would partially re-equilibrate after this event during partial melting in a gas enriched in light Ge isotopes. This model of metal melting before OC accretion agrees with a recent study of metal formation in L OCs[START_REF] Okabayashi | Fractionation of highly siderophile elements in metal grains from unequilibrated ordinary chondrites: Implications for the origin of chondritic metals[END_REF]. No shock effect on δ 74/70 Ge metal and δ 74/70 Ge bulk values As the germanium is a moderately volatile element, evaporation should result in a significant enrichment in heavy isotopes in highly shocked samples. The H chondrite Roses City, an impact melt breccia (S6), shows no deviation in δ 74/70 Ge metal from the mean values for H group while Dhajala (S1) is enriched in heavy isotopes compared with other H chondrites. Similarly, for L group samples, there is no δ 74/70 Ge metal difference between highly shocked (Alfianello and Vouillé, both S5) and minimally shocked samples (Bjürbole, S1). The lack of a shock effect on the δ 74/70 Ge values can be explained by the deep burial of material, which should inhibit light

	4.3. Post accretional processes
	4.3.1.

  . In Semarkona, type I and II chondrules both have similar Δ 17 O values (+0.5-0.7‰) that are lower than bulk LL chondrites (+1.2‰), indicating that chondrule phenocrysts do not host the Δ 17 O anomalies. Thus, the issue is not the dichotomy between the O isotopic compositions of type I and II chondrules but the recognition of a high Δ 17 O anomaly. For example, a previous study has found a Δ 17 O anomaly in chondrule glass from the LL chondrite, which resulted from aqueous alteration with a high Δ 17 O ice component[START_REF] Kita | High precision SIMS oxygen three isotope study of chondrules in LL3 chondrites: Role of ambient gas during chondrule formation[END_REF]. Germanium isotopes and detailed studies of O anomalies in chondrules do not favor a mixing model that links phenocrysts in type I and II chondrules with the redox state but mixing with, or incorporation of, a high Δ 17 O oxidized component in the chondrules or chondrite matrix is a viable model. The similar Ge isotopic composition between the type I and II chondrules suggests that evidence of an oxidizing component with high Δ 17 O must occur in the matrix of ordinary chondrites. A systematic investigation of the Ge isotopic compositions of chondrules and the matrix of the H, L, and LL types is necessary to understand similarities in their composition. 4.4.2. δ 74/70 Ge-Δ 17 O-%Fa correlations in OCs and accretion of hydrated phyllosilicate

  Table 5 for oxygen references). IIE iron meteorite values for δ 74/70 Ge metal and Δ 17 O silicate inclusions are lower than those for the H chondrites. As the H chondrites are the less oxidized group, the lower δ 74/70 Ge metal and Δ 17 O silicate inclusion values (Fig.9) of the IIE old groups compared to the H group, correspond to the isotopic composition of the most reduced HH parent body. Germanium isotopes demonstrate that there is a genetic link between the IIE iron meteorites and HH parent body.

  Table 1 lists all abbreviations.

Table 1 .

 1 The H, L, and LL ordinary chondrites analyzed in this study, with their petrologic types and shock stages. All meteorites are falls.

	[1]: Stöffler (1991); [2]: Rubin (1994); [3]: Reisener And Goldstein (2003); [4]: Rubin (2003); [5]:
	Dodd and Jarosewich (1979); [6]: Bennett and Mc Sween (1996); [7]: Grossman and Zipfel
	(2001).
	Abbreviations: MNCN, Museo Nacional de Ciencias Naturales, Madrid; MNHN, Muséum
	National d'Histoire Naturelle, Paris; SI, Smithsonian; USNM, United States National Museum,
	Washington; IB, Impact Breccia

Table 2 .

 2 The Ge isotopic compositions of standards and geostandards, cleaning tests on San Carlos olivines for silicate purification, and BIR-1 digestion in Bola Teflon bombs at 150°C and 25 bar. Germanium concentrations were measured using an ICP-MS X-Series at CRPG, with a precision of less than 2%. n is the number of replicates.Value from[START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF].(2) Value from[START_REF] Luais | Germanium chemistry and MC-ICPMS isotopic measurements of Fe-Ni, Zn alloys and silicate matrices: Insights into deep Earth processes[END_REF].

		Ge ppm	δ 72/70 Ge ‰	± 2SD	δ 73/70 Ge ‰	± 2SD	δ 74/70 Ge ‰	± 2SD	n
	In-house
	standard
	Magura (IAB iron)	427 (1)	0.42	0.06	0.58	0.11	0.78	0.08	1 9
	Standard
	solutions
	JMC-Ge		-0.15	0.08	-0.19	0.13	-0.32	0.11	9 5
	Aldrich-Ge		-1.01	0.07	-1.52	0.13	-1.97	0.12	9 9
	Geostandards
	BIR-1
	Hotplate digestion	1.52 (2)	0.32	0.04	0.42	0.07	0.59	0.06 7
	Bomb digestion	1.50	0.31	0.05	0.42	0.14	0.59	0.01 3
	San Carlos
	Olivines
	Un-cleaned	0.89	0.35	0.04	0.48	0.08	0.70	0.08 3
	Cleaned	0.90	0.36	0.03	0.47	0.14	0.71	0.09 3
	(1)

Table 3 .

 3 The Ni, Co

Table 4 .

 4 The germanium isotopic factor among the bulk, metal, silicate, and sulfide of H ordinary chondrites, as well as the Ge elemental fractionation between metal and silicate.

	Bjürbole (L4)	18.1 5	8400	0.04 6	174.5	-0.16	0.03	-0.24	0.04	-0.32	0.02 3
	Alfianello (L6)	11.6 7042	0.06 1	117.5	-0.11	0.03	-0.19	0.03	-0.28	0.01 2
	Granes (L6)	15.7 6	5242	0.03 3	120.7	-0.16	0.01	-0.25	0.03	-0.33	0.05 3
	Tourine la Grosse (L6)	21.2 1	5466	0.02 6	157.8	-0.17	0.07	-0.24	0.07	-0.3	0.09 4
	Vouillé (L6)	14.1 8	6806	0.04 8	140.4	-0.11	0.02	-0.20	0.07	-0.28	0.04 3
	Mean	15.2 6454	0.04 5	135.9	-0.15	0.05	-0.24	0.08	-0.31	0.06
	Silicate
	Hedjaz (L3.7)				0.23	-0.32	0.02	-0.58	0.41	-0.85	0.22 2
	Bjürbole (L4)				0.65	-0.27	0.05	-0.40	0.12	-0.50	0.09 5
	Alfianello (L6)				0.05	-0.57		-0.92		-1.25	1
	Granes (L6)				0.18	-0.44	0.21	-0.69	0.07	-0.92	0.25 2
	Vouillé (L6)				0.24	-0.22		-0.51		-0.83	1
	Mean				0.27	-0.36	0.09	-0.62	0.2	-0.87	0.18
	LL ordinary
	chondrites
	Metal
	Parnalle (LL3.6)				120	-0.18	0.07	-0.31	0.17	-0.29	0.08 3
	NWA 118 (LL6)				85	-0.13	0.06	-0.19	0.1	-0.23	0.10 4
	Mean				102.5	-0.16	0.07	-0.25	0.2	-0.26	0.09

Table 5 .

 5 The oxygen Isotopic compositions and percentage of fayalite (%Fa) in ordinary chondrites.

	References : 1: Clayton et al. (1991); 2: Folco et al. (2004); 3: This study; 4: Rubin (1990); 5:
	Dodd (1968); 6: Dodd & Jarosewich (1979); 7: Reisener et al. (2006); 8: Grossman & Zipfel
	(2001); 9: Mason (1963); 10: Clayton & Mayeda (1996)

Acknowledgments

The authors thank Damien Cividini for his valuable assistance on the NeptunePlus MC-ICP-MS and his advice on germanium chemistry, and Delphine Yeghicheyan (SARM "Service d'Analyses des Roches et des Minéraux", CRPG-CNRS, Nancy) for contribution to elemental analyses.

The authors also acknowledge Andreas Pack for oxygen isotopic measurements. We thank M. Gounelle and the "Comité de gestion" at the "Muséum National d'Histoire Naturelle" (MNHN) of Paris, T. McCoy and J. Hoskin from the Smithsonian Institute, and A. Nieto Codina from the "Museo Nacional de Ciencias Naturales" (MNCN) of Madrid for providing the meteorite samples.

Jesse Davenport is thanked for his kind and careful correction of the manuscript. Finally, we thank Fang Huang for editorial handling, and three anonymous reviewers for their thorough and constructive reviews that helped to improve the manuscript. This is CRPG contribution n°2724.

Research Data

Research

Data associated with this article can be access at https://doi.org/10.17632/5rfdtkx27w.1

 [START_REF] Luais | Isotopic fractionation of germanium in iron meteorites: Significance for nebular condensation, core formation and impact processes[END_REF]. Large errors for sulfide result from the small amount of measured Ge due to its low Ge concentration. Ge isotopic compositions become lighter from metal to bulk, silicate, and, then, to the sulfide phase. Identical trends as the δ 74/70 Ge versus δ 73/70 Ge diagram.

Declaration of interests

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

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