# Origin and timing of volatile delivery (N, H) to the angrite parent body: Constraints from in situ analyses of melt inclusions

Cécile Deligny, Evelyn Füri, Etienne Deloule

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Cécile Deligny, Evelyn Füri, Etienne Deloule. Origin and timing of volatile delivery (N, H) to the angrite parent body: Constraints from in situ analyses of melt inclusions. Geochimica et Cosmochimica Acta, 2021, 313, pp.243-256. 10.1016/j.gca.2021.07.038. hal-03360798

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# Origin and timing of volatile delivery (N, H) to the angrite parent body: Constraints from in situ analyses of melt inclusions

C. Deligny *, E. Füri, E. Deloule

Université de Lorraine, CNRS, CRPG, F-54000 Nancy, France

Received 30 April 2021; accepted in revised form 29 July 2021; Available online 4 August 2021

## Abstract

Angrites are derived from the earliest generation of differentiated planetesimals that accreted sunward of Jupiter's orbit, and are, thus, key to constraining the timing and source(s) of volatile delivery to planetary bodies in the inner solar system. Here we investigate the nitrogen and hydrogen isotopic signatures of angrite melts by *in situ* secondary ion mass spectrometry (SIMS) analyses of mineral-hosted melt inclusions and interstitial glass in two of the oldest volcanic angrites: D'Orbigny and Sahara 99555. The most primitive melt trapped in Mg-rich olivines in D'Orbigny is characterized by $\delta^{15}N$ values ranging from 0 ± 25 to +56 ± 29‰ and $\delta\text{D}$ values between -348 ± 53 and -118 ± 31‰. This shows that the angrite mantle source sampled by D'Orbigny has a N-H isotopic composition that is similar to that of CM carbonaceous chondrites, whose parent bodies are thought to have accreted in the outer solar system. The low nitrogen and water contents measured in Sahara 99555 possibly indicate that its parental melt underwent a higher degree of degassing compared to D'Orbigny or, alternatively, that the two angrites do not sample the same volatile reservoir within the angrite parent body. Given the very old crystallisation age of D'Orbigny, our findings imply that nitrogen- and water-rich objects, presumably formed beyond the orbit of Jupiter, must have been present in the terrestrial planet-forming region within the first ~4 Ma after the formation of Ca-Al-rich inclusions (CAIs, the oldest materials in the solar system).

© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Keywords: Angrites; Nitrogen; Water; SIMS; Volatile accretion

## 1. INTRODUCTION

The origin and timing of the accretion of nitrogen and water on Earth remains a subject of controversy. Although Earth formed in the inner solar system, i.e., sunward of Jupiter and presumably within the snowline (Morbidelli et al., 2015; Bermingham et al., 2020), it accreted volatile elements, as evidenced by the oceans and atmosphere. Enstatite chondrite-like bodies, which are isotopically akin to Earth's main building blocks (Dauphas, 2017), appear to be the dominant source of nitrogen in Earth's primitive mantle (Javoy et al., 1986; Dalou et al., 2019a). Further-

more, Piani et al. (2020) recently demonstrated that a significant, perhaps even dominant, fraction of water in the terrestrial mantle could be derived from material similar to enstatite chondrite meteorites. However, terrestrial mantle-derived samples record a wide range of hydrogen isotopic compositions ($\delta\text{D}$), which encompass low, solar-like $\delta\text{D}$ values (Hallis et al., 2015), as well as higher values measured in enstatite and carbonaceous chondrites (Peslier et al., 2017 and references therein; Loewen et al., 2019), suggesting that various sources contributed to Earth's water inventory. Notably, the isotopic signature of nitrogen and hydrogen in the atmosphere and the oceans is more consistent with a carbonaceous chondrite (CI/CM) source (Alexander et al., 2012; Alexander, 2017), thus requiring the inward transport of volatile-rich material from greater heliocentric distances to the terrestrial planet-forming

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: cecile.deligny@univ-lorraine.fr (C. Deligny).</footnote>
region. Alternatively, an isotopically carbonaceous chondrite-like volatile reservoir may have already been present in the inner solar system during the earliest stages of planet formation (Sarafian et al., 2014; McCubbin and Barnes, 2019).

As different solar system reservoirs (solar, chondritic, cometary) have unique N and H isotopic signatures (Alexander et al., 2012; Füri and Marty, 2015; Alexander, 2017), the N and H isotopic compositions of differentiated meteorites with well-known ages can better constrain the source(s) and timing of volatile delivery to planetary bodies in the inner solar system. Angrites are mafic to ultramafic achondrites that formed by melting in the mantle of a differentiated body, and their ⁵⁴Cr and ⁵⁰Ti isotopic compositions imply that the angrite parent body (APB) accreted sunward of Jupiter's orbit in the non-carbonaceous reservoir (Zhu et al., 2019; Kruijer et al., 2020; Kleine et al., 2020 and references therein). Although the APB remains unidentified, near-infrared reflectance spectra of asteroids highlight the presence of angrite analogues in the main asteroid belt, suggesting that the APB formed between 2.8 and 2.9 AU (Nyquist and Bogard, 2003; Keil, 2012 and references therein). ²⁶Al-²⁶Mg and Hf-W data indicate that the APB accreted within the first ~0.4 to 1.5 Ma after CAI formation (Kleine et al., 2012; Schiller et al., 2015).

D'Orbigny and Sahara 99555 are two of the oldest volcanic angrites, with Pb-Pb ages of 4,563.51 ± 0.8 and 4,564.07 ± 0.43 Ma, respectively (Tissot et al., 2017, and references therein). Both are fine-grained quenched rocks with similar bulk compositions and mineralogies, and they contain hollow spheres/vugs, which presumably formed as a result of degassing and coalescence of CO₂ or SO₂ bubbles (McCoy et al., 2003; McCoy et al., 2006, Irving and Kuehner, 2007). D'Orbigny and Sahara 99555 contain abundant mineral-hosted melt inclusions (Bischoff et al., 2000; Mikouchi et al., 2000; Kurat et al., 2001; Mikouchi and McKay, 2001; Mittlefehldt et al. 2002; Floss et al., 2003; Keil, 2012), but D'Orbigny is unique in that it contains interstitial glass and glass beads (Varela et al., 2003). Two different types of melt inclusions have been identified in D'Orbigny: i) primary melt inclusions composed of glass, a bubble, and, occasionally, a sulphide globule, and ii) multi-phase melt inclusions that consist of glass with olivine, pyroxene, and a bubble (Varela et al., 2003). It is also noteworthy that D'Orbigny is a complex rock, consisting of a porous part with hollow spheres of variable size surrounded by two dense parts (Kurat et al., 2001, 2004; Mittlefehldt et al., 2002; Varela et al., 2003). Both meteorites are unrecciated and unshocked, and they show no evidence of thermal metamorphism; thus, the characteristics of any volatile elements trapped in the two meteorites are not expected to have been modified by secondary processes (Kurat et al., 2001; Mittlefehldt et al., 2002; Keil, 2012 and references therein; Sanborn and Wadhwa, 2021).

In situ nuclear microanalyses of N and C contents in D'Orbigny demonstrate that olivine-hosted melt inclusions contain up to 180 ppm N and 40–735 ppm C depending on their composition (Varela et al., 2003). Nitrogen extracted by step-heating analyses of D'Orbigny and Sahara 99555 shows a slight enrichment in ¹⁵N compared to Earth's

atmosphere (δ¹⁵N = +34.8 ± 10.7‰ for bulk rock chips and +20.3 ± 3.6‰ for glass of D'Orbigny; +9.4 ± 3.4‰ for Sahara 99555 fragments at T ≥ 850 °C; Abernethy et al., 2013, 2018). These δ¹⁵N values have been explained by degassing-induced N isotope fractionation on the APB (Abernethy et al., 2018), which would imply that the parent melt of Sahara 99555 is less degassed than that of D'Orbigny. Furthermore, the heavy hydrogen isotopic composition of silicophosphates in D'Orbigny (δD<sub>D'Orbigny</sub> = -205 to +1034‰ versus δD<sub>Sahara99555</sub> = -262 to -35‰) compared to that of a glass bead (δD<sub>D'Orbigny</sub> = -154 to +115‰) and coexisting olivine (δD<sub>D'Orbigny</sub> = -146 to +61‰ and δD<sub>Sahara99555</sub> = -83 to +46‰) suggests that the melt lost an important portion of 'water' due to extreme H₂ degassing (Sarafian et al., 2017). These observations indicate that the APB accreted a significant amount of highly volatile elements (H, C, N) during the earliest period of planetary formation and evolution. Given that angrites are considered to be the most (lithophile) volatile-depleted basalts in the solar system, with ~1000 times and ~100 times lower Rb/Sr and K/U ratios, respectively, than CI chondrites (O'Neill and Palme, 2008; Day and Moynier, 2014), this raises the question of the source(s) of nitrogen and hydrogen trapped in the APB.

Melt inclusions are encapsulated in their host mineral during crystal growth, and thus provide key information on the volatile element composition of their parental melt. Glassy melt inclusions, 5–65 µm in diameter, are found in both D'Orbigny and Sahara 99555 (Fig. 1). Therefore, we applied here an *in situ* large geometry SIMS method (Füri et al., 2018) to characterize the N and H contents and isotopic compositions of melt inclusions, interstitial glasses, and silicate minerals (anorthite, olivine and pyroxene) in four polished sections (N1, N1138, N1179, and NMW1) of D'Orbigny and one of Sahara 99555 (SAH1) to improve our understanding of the volatile origin of the APB.

## 2. MATERIALS AND METHODS

### 2.1. Sample preparation and imaging

Four polished sections (N1, N1138, N1179, and NMW1) of D'Orbigny and one of Sahara 99555 (SAH1) were prepared for *in situ* major and volatile (N, H) element analyses. A 0.7 g fragment of D'Orbigny was purchased from a reputable meteorite dealer (meteorites-for-sale.com), cut, polished, and mounted in epoxy at the Centre de Recherches Pétrographiques et Géochimiques (CRPG, Nancy, France). This section (N1) originated from the dense part of the meteorite. Two samples mounted in epoxy (N1138 and N1179) were provided by the Naturhistorisches Museum Wien (NMW). N1138 contains five hollow spheres and is derived from the porous part of D'Orbigny. N1179 contains one large hollow sphere (~2 mm in diameter) and corresponds to the junction between the dense and the porous portion of the meteorite. The NMW also provided a pristine fragment of D'Orbigny (~1 g) that was cut into different slices using a wire saw with ethanol as a lubricant, and then polished with alumina powder and ethanol to avoid contamination by terrestrial water
<figure><img src="image_2.png" /><figcaption>Fig. 1. Backscattered electron images of D'Orbigny and Sahara 99555. (a) Interstitial glass in the dense part of D'Orbigny (section N1). (b) Melt inclusions in the porous part of D'Orbigny (section N1138) and (c) at the junction between the dense and the porous parts of D'Orbigny (section N1179). (d) Melt inclusion in the dense part of Sahara 99555 (section SAH1). (e) Multiphase melt inclusions located in the dense part of D'Orbigny (section N1) and (f) one multiphase melt inclusion near a hollow sphere (N1179 section). An: Anorthite, Py: Pyroxene, Gl: Glass, Mg: Mg-rich olivine, Fe: Fe-rich olivine, Kir: Kirschsteinite, Ul: Ulvöspinel, Ts: Tsangpoite, Tr: Troilite, Ep: Epoxy. Pink circles indicate melt inclusions hosted in Mg-rich and Fe-rich olivines that were targeted for SIMS analyses (spot size ~15 µm with a 10 × 10 µm raster).</figcaption></figure>

(NMW1). The fragment prepared for SIMS analyses was cut from the dense part of the sample. In addition, the Institut für Planetologie der Westfälischen Wihelms-Universität Münster supplied a small fragment of Sahara 99555 that was prepared without water in the same way as NMW1. Since this fragment (SAH1) contains no hollow spheres, it likely originates from the dense part of the meteorite. These two samples (NMW1, SAH1) were pressed into separate indium sample holders

Backscattered electron (BSE) images of all meteorite sections were acquired by scanning electron microscopy (JEOL JSM-6510) to select areas of interest for subsequent major and volatile (N, H) element analyses. BSE and elemental maps confirmed that D'Orbigny and Sahara 99555 are mainly composed of anorthite, olivine (Mg-rich olivine,

Fe-rich olivine, and kirschsteinite) and pyroxene. Zonations due to compositional variations (e.g., calcium zonations in olivine) are observed in olivine and pyroxene of both angrites (Fig. 1b–f). The mineralogy and composition are the same in the dense and porous parts of D'Orbigny, and only the mineral size varies with proximity to the hollow spheres. Iron sulfide (troilite), ulvöspinel, and silicophosphate (tsangpoite) were observed near several melt inclusions and in the interstitial space where the most evolved melt was preserved as glass upon quenching (Fig. 1a; Fig. 2). Mittlefehldt et al. (2002) argued that olivine (Mg-rich and Fe-rich) was the first mineral to form. Anorthite tends to crystallise with olivine, followed by pyroxenes with Fe and Al zonations (Mittlefehldt et al., 2002).
<figure><img src="image_3.png" /><figcaption>Fig. 2. Backscattered electron maps of the distribution of phosphorus (indicated in red) in D'Orbigny. (a, b) The presence of tsangpoite (a silicophosphate) near or within melt inclusions and interstitial glass results in elevated measured δ¹⁵N values due to the contribution of the ³¹P⁻ peak tail to the ¹⁵N¹⁶O⁻ signal. (c, d) Melt inclusions without tsangpoite yield low δ¹⁵N values. An: Anorthite, Py: Pyroxene, Mg: Mg-rich olivine. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>

## 2.2. Electron Probe Microanalysis (EPMA)

Major (Si, Al, Fe, Mg, Ca, Na) and minor (Ti, Mn, Cr, K) element compositions of minerals, melt inclusions, and interstitial glass were determined during two analytical sessions by EPMA (CAMECA SX-100 and SX-FIVE) at Camparis service (Université Pierre et Marie Curie, Paris, France), using a beam current of 40nA and acceleration voltage of 15 kV. A suite of natural reference materials was used for calibration and instrument stability monitoring: olivine for Mg and Si, K-feldspars for K and Al, iron oxide for Fe, albite for Na, diopside for Ca, manganese titanite for Mn and Ti, and chromite for Cr. On-peak and background counting times were 40 s for all elements. Cross-sectional profiles in minerals and spot analyses (melt inclusions, and interstitial glass, *n* = 75) were performed on all sections of both meteorites. The quality of all analyses was carefully assessed, and results with totals below 97.5% or above 102.5% were discarded (Table S1).

## 2.3. Secondary Ion Mass Spectrometry (SIMS)

In situ analyses of nitrogen and hydrogen abundances and isotopic ratios in (fracture-free) minerals and glasses of D'Orbigny and Sahara 99555 were performed using the

CAMECA 1280 HR2 ion microprobe at the CRPG. To minimize any contamination from terrestrial adsorbed water, the polished sections were placed in an oven for ~72 hours at 35 °C before carbon coating (~30 nm thickness), and the sample mounts were kept under vacuum in the airlock of the SIMS for several days prior to each analytical session.

### 2.3.1. Nitrogen contents and isotopic ratios

Nitrogen abundances and isotopic ratios were determined using a 10 kV Cs⁺ primary ion beam with a current of 10nA and a spot diameter of ~15 µm, following the analytical protocol of Füri et al. (2018). A normal-incidence electron gun was used for charge compensation. Samples were pre-sputtered for 180 s with a beam raster of 10 × 10 µm prior to signal acquisition to minimize surface contamination. ¹⁴N¹⁶O⁻ and ¹⁵N¹⁶O⁻ were measured in peak-jumping mono-collection mode on an electron multiplier, whereas ²⁷Al⁻, ³⁰Si⁻, and ¹⁶O₂⁻ were measured on a Faraday cup (FC2). The EM background was carefully monitored for N-poor calibrants and “N-free” minerals (N ≤ 1 ppm) of both meteorites; thus, the EM background (≤0.04 cps) was found to be too low to contribute to the ¹⁵N¹⁶O⁻ signals (≥10 cps) reported for D'Orbigny and Sahara 99555. Twenty-five cycles were collected for each
analysis through the mass sequence $ ^{27}\text{Al}^- (4 \text{s}), \ ^{30}\text{Si}^- (4 \text{s}), \ ^{14}\text{N}^{16}\text{O}^- (6 \text{s}), \ ^{15}\text{N}^{16}\text{O}^- (20 \text{s}), \ \text{and} \ ^{16}\text{O}_2^- (4 \text{s}). A nominal mass resolution ($m/\Delta m$) of ~11,000 was used to resolve interferences from silicon hydrides ($^{28}\text{SiH}_2^- \text{ and } ^{29}\text{SiH}_2^-$) on masses 30 ($^{14}\text{N}^{16}\text{O}^-$) and 31 ($^{15}\text{N}^{16}\text{O}^-$). Synthetic basal- tic glasses with nitrogen contents ranging from 0.022 ± 0. 034 to 3,906 ± 188 ppm were used as reference materials. The nitrogen content of minerals ($n = 10$ for each mineral, i.e., olivine, pyroxene, and anorthite), melt inclusions ($n = 89$), and interstitial glass ($n = 17$) in D'Orbigny and melt inclusions in Sahara 99555 ($n = 41$), was derived from the relationship between the secondary ion intensity ratio $^{14}\text{N}^{16}\text{O}^- / ^{16}\text{O}_2^-$ and the known nitrogen content of the refer- ence glasses (Fig. S1). This method has been demonstrated to yield nitrogen abundances ($\le 1$ to 6000 ppm N) in silicate glasses of variable compositions that are in excellent agree- ment with results from static mass spectrometry analyses (Boullioug et al., 2020).

The $^{15}\text{N}^{16}\text{O}^- / ^{14}\text{N}^{16}\text{O}^-$ isotope ratios are reported as $\delta^{15}\text{N}$ values, where $\delta^{15}\text{N}$ is the permil deviation from the atmospheric ratio $^{15}\text{N} / ^{14}\text{N}_{\text{atm}} = 0.003676$ ($\delta^{15}\text{N} = [(^{15}\text{N} / ^{14}\text{N}_{\text{sample}} / ^{15}\text{N} / ^{14}\text{N}_{\text{atm}}) - 1] \times 1000$). Values are reported only for spot analyses with a significant secondary beam inten- sity ($^{14}\text{N}^{16}\text{O}^- \ge 1,000 \text{ cps}$; $^{15}\text{N}^{16}\text{O}^- \ge 10 \text{ cps}$), correspond- ing to $^{14}\text{N}$ contents $\ge 50$ ppm. For the synthetic reference glasses containing $\ge 136$ ppm N (with $\delta^{15}\text{N} = -4 \pm 1\%$; Füri et al., 2018, and references therein), the weighted mean $^{15}\text{N}^{16}\text{O}^- / ^{14}\text{N}^{16}\text{O}^-$ ratio was $(3.746 \pm 0.0016) \times 10^{-3}$ ($\delta^{15}\text{N} = +19.1 \pm 1.2\%$) from 95 spot analyses (Fig. S2), consis- tent with the measured average (i.e., $\delta^{15}\text{N} = +20.0\%$) reported by Füri et al. (2018). Although the two calibrants with low N contents (136 and 162 ppm N) showed a larger scatter ($\delta^{15}\text{N} = -8.9 \pm 11.4$ to +29.9 ± 14‰) due to lower $^{15}\text{N}^{16}\text{O}^-$ count rates, all isotopic ratios measured in the meteorites were corrected for an instrumental mass frac- tionation ($\Delta_{\text{inst}}$) of +23.1‰.

Given the high mass resolution, the presence of silicon hydrides ($^{29}\text{SiH}_2^-$) has no effect on the peak intensity of $^{15}\text{N}^{16}\text{O}^-$ measured in both angrites, i.e., $\delta^{15}\text{N}$ values are not affected by the presence of water. However, the pres- ence of silicophosphates (tsangpoite) near a few melt inclu-

sions and within interstitial glass (Fig. 2a and b) increases the $^{31}\text{P}^-$ peak intensity by about one order of magnitude, resulting in a residual contribution of the $^{31}\text{P}^-$ peak tail at the mass of $^{15}\text{N}^{16}\text{O}^-$ (Fig. 3a). Consequently, the $^{15}\text{N}^{16}\text{O}^-$ signal increases due to the high intensity of $^{31}\text{P}^-$, and the $^{15}\text{N} / ^{14}\text{N}$ ratios measured are too high (see Table S2). Since the contribution of $^{31}\text{P}^-$ on $^{15}\text{N}^{16}\text{O}^-$ is dif- ficult to quantify precisely, N isotope ratios for SIMS spots located near tsangpoite are excluded from further discussions. In melt inclusions without tsangpoite, the $^{31}\text{P}^-$ peak does not contribute to the $^{15}\text{N}^{16}\text{O}^-$ peak (Figs. 2c, d and 3b).

### 2.3.2. *Hydrogen contents and isotopic ratios*

The water contents (i.e., hydrogen content as equivalent H₂O) were determined in minerals ($n = 10$ for each mineral, i.e., olivine, pyroxene, and anorthite), melt inclusions ($n = 33$), and interstitial glass ($n = 5$) in D'Orbigny and melt inclusions in Sahara 99555 ($n = 4$), and hydrogen iso- tope ratios were determined for a subset of glasses (see below). A 10 kV Cs⁺ primary ion beam with a current of 3 nA and a spot diameter of ~10 µm was used. A normal- incidence electron gun was used for charge compensation. In order to minimize surface contamination, the samples were pre-sputtered for 60 s with a beam raster of 10 × 10 µm prior to signal acquisition. $^{16}\text{OD}^-$, $^{17}\text{O}^-$ and $^{17}\text{O}^1\text{H}^-$ were detected in peak-jumping mono-collection mode on an electron multiplier together with $^{16}\text{O}^1\text{H}^-$ and $^{18}\text{O}^-$ on a Faraday cup (FC2). A nominal mass resolution of ~12,000 was used to separate the $^{17}\text{O}^1\text{H}^-$ and $^{16}\text{OD}^-$ sig- nals. The EM background was carefully measured for H- poor standards, and was found not to contribute ($\le 0.09 \text{ cps}$) to the $^{16}\text{OD}^-$ signal ($\ge 15 \text{ cps}$) reported for D'Orbigny and Sahara 99555. Twenty cycles were collected for each analysis through the mass sequence $^{17}\text{O}^-$ (3 s), $^{16}\text{O}^1\text{H}^-$ (4 s), $^{18}\text{O}^-$ (4 s), $^{17}\text{O}^1\text{H}^-$ (4 s), and $^{16}\text{OD}^-$ (20 s). Glasses from Etna, Mt. St. Helens, and Tania with variable water abundances (0.0250 ± 0.0025 to 4.29 ± 0.15 wt.%; Métrich and Deloule, 2014) were used as reference materi- als, and the calibration line is shown in Fig. S3.

<figure><img src="image_4.png" /><figcaption>Fig. 3. High-resolution mass spectra at mass 31 for melt inclusions in D'Orbigny (counting time = 0.56 s per analysis point). (a) The presence of tsangpoite increases the intensity of the $^{31}\text{P}^-$ peak, thereby resulting in an elevated signal at mass $^{15}\text{N}^{16}\text{O}^-$. (b) In the absence of tsangpoite, there is no contribution of the $^{31}\text{P}^-$ peak tail to the $^{15}\text{N}^{16}\text{O}^-$ peak.</figcaption></figure>
Since the three sections N1, N1138, and N1179 were cut and/or polished with water, the water background was carefully monitored to assess the importance of contamination due to sample preparation. The $^{16}$O$^{1}$H$^{-}$ background measured on olivine was on the order of 85,500 cps (corresponding to ~1250 ppm H$_{2}$O) for the sections polished with water (N1, N1138, N1179), and 9740 cps (166 ppm H$_{2}$O) for the sections prepared with ethanol (NMW1, SAH1). All measurements on minerals and amorphous phases from the meteorite sections polished with water (N1, N1138, and N1179) were corrected for water contamination (~1100 ppm was subtracted from the contents initially measured) by assuming that measurements of sections NMW1 and SAH1 were contamination-free. Importantly, this approach yields similar water concentrations in all four analyzed sections of D'Orbigny (see Table S2).

The D/H ratios are reported as δD values relative to Standard Mean Ocean Water (SMOW; D/H$_{SMOW}$ = 1.557 × 10⁻⁴), calculated as δD = [(D/H$_{sample}$/D/H$_{SMOW}$) - 1] × 1000. The two water-poor standards StHs6/80-G (250 ± 25 ppm) and T1G (260 ± 26 ppm) showed a significant scatter in δD (−109 ± 58 to +384 ± 33‰) due to low $^{16}$O$^{1}$H$^{-}$ and $^{16}$OD$^{-}$ count rates as well as a significant background noise on FC2 (Fig. S4). Consequently, δD values are reported only for spot analyses with a significant secondary beam intensity ($^{16}$O$^{1}$H$^{-}$ ≥ 80,000 cps; $^{16}$OD$^{-}$ ≥ 15 cps), corresponding to water contents ≥ 1000 ppm. The weighted mean D/H ratio measured on the six andesitic/basaltic reference glasses with water contents ranging from 0.74 to 4.29 wt.% was (1.8492 ± 0.0013) × 10⁻⁴ (δD = +178.9 ± 7.1‰) from a total of 69 measurements. The D/H ratios of all the different phases analysed in both meteorites were thus corrected for instrumental mass fractionation $\Delta_{inst}$ = +340‰. In addition, the contaminant water was found to have a δD value of −180.1‰; hence, the D/H ratios were corrected for contamination based on the following equation:

$$D/H_{\text{measured}} = D/H_{\text{sample}} \times f_{\text{sample}} + D/H_{\text{contamination}} \times f_{\text{contamination}},$$

where $f_{sample}$ and $f_{contamination}$ are the fractions of the D/H signal coming from the sample and the contamination, respectively. Again, this approach yields δD values for sections N1, N1138, and N1179 that are comparable to those observed in the contamination-free sections NMW1 and SAH1, for which no correction was applied (see Table S2).

As mentioned above, a few glass inclusions and interstitial glass contain tsangpoite, which can contain up to ~2000 ppm of water (Sarafian et al., 2017). However, given the high water contents measured here, the presence of silicophosphates has no effect on the reported water concentrations and D/H ratios in D'Orbigny and Sahara 99555 glasses.

## 2.4. Corrections for cosmogenic $^{15}$N and D

After the ejection of a meteorite from its parent body, and during its transit to Earth, high-energy solar and galactic cosmic rays interact with elements in the mineral lattice,

producing 'cosmogenic' (or 'spallogenic') nuclides such as $^{15}$N and D. The abundance of cosmogenic $^{15}$N and D depends on the duration of cosmic ray irradiation and the production rates, which themselves depend on the meteorite composition (i.e., the abundance of the parent element oxygen, in both cases; Reedy, 1981) and shielding conditions. Here, the spallation effect was corrected for both meteorites with average production rates of 5.6 pg·(g rock)⁻¹·Ma⁻¹ for $^{15}$N (Hashizume et al., 2002) and of 2.17 × 10⁻¹² mol·g⁻¹·Ma⁻¹ for D (Füri et al., 2017, 2020). The exposure ages of D'Orbigny and Sahara 99555 are 11.9 ± 1.2 Ma and 6.8 ± 0.3 Ma, respectively (Busemann et al., 2006). Due to the short exposure duration of the two angrites, the correction for cosmogenic $^{15}$N and D is virtually negligible, with a maximum correction of 27‰ and 21‰ for $^{15}$N and $^{16}$D, respectively, for N- or D-poor measurements. Importantly, for N contents ≥115 ppm, the correction was only ≤3‰.

## 3. RESULTS

### 3.1. Nitrogen concentrations and isotopic compositions of D'Orbigny and Sahara 99555

The nitrogen contents of interstitial glass and melt inclusions within olivine (Mg- and Fe-rich), anorthite, and pyroxene in D'Orbigny vary from ≤1 to 567 ± 118 ppm (n = 106), and N isotopic compositions ($^{15}$N, corrected for cosmogenic $^{15}$N; see Section 2.4) of glasses containing ≥50 ppm N range from 0 ± 25 to +273 ± 87‰ (n = 22; Fig. 4a). The nitrogen concentrations and isotopic ratios of interstitial glass and melt inclusions in the dense and porous parts of the meteorite show similar variations (Table S2). Highly variable $^{15}$N values (+20 ± 49 to +273 ± 87‰) are observed for low nitrogen concentrations (≤250 ppm), whereas the inclusions with the highest nitrogen contents (≥250 ppm) have low and more homogeneous nitrogen isotopic ratios (0 ± 25 to +56 ± 29‰). It is noteworthy that the isotopic composition of N-rich inclusions is remarkably similar to the values of +20.3 ± 3.6‰ and +34.8 ± 10.7‰ obtained by Abernethy et al. (2013, 2018) for D'Orbigny bulk rock chips and glass, respectively, using static mass spectrometry. The low nitrogen contents (≤1 to 24 ± 1 ppm, n = 41; Table S2) of glasses in Sahara 99555 preclude determination of their nitrogen isotopic compositions. Nitrogen concentrations in the minerals themselves are negligible (below the detection limit; n = 30).

For D'Orbigny, the nitrogen isotopic compositions of the melt inclusions and interstitial glass appears to be related to their magnesium number (Mg# = 100 × MgO/[MgO + FeO]; Fig. 4b), an indicator of the degree of magnetic differentiation, as Mg# decreases in the residual melt during fractional crystallisation. The $^{15}$N values of inclusions hosted in Mg-rich olivine (i.e., the most primitive inclusions) vary from 0 ± 25 to +82 ± 55‰ and the magnesium number from 49 to 23. Melts trapped in subsequently formed minerals and interstitial glasses have lower Mg# (≤15.4) and variable $^{15}$N values from +23 ± 35 to +273 ± 87‰.
<figure><img src="image_5.png" /></figure>

Fig. 4. Nitrogen isotopic composition (δ¹⁵N, corrected for cosmogenic ¹⁵N; see Section 2.4) as a function of (a) nitrogen content of melt inclusions and interstitial glass as well as (b) Mg# of a subset thereof. Error bars indicate 2σ uncertainties. The low nitrogen contents of glasses in Sahara 99555 (<50 ppm, Table S2) precluded δ¹⁵N determinations. The δ¹⁵N values of D'Orbigny bulk rock fragments and glass measured by Abernethy et al. (2013, 2018) by static mass spectrometry are indicated for comparison (grey rectangle). MI: Melt Inclusion.

<figure><img src="image_6.png" /></figure>

Fig. 5. (a) Hydrogen isotopic compositions (δD, corrected for cosmogenic D; see Section 2.4) as a function of water content in melt inclusions and interstitial glass of D'Orbigny (filled symbols) and Sahara 99555 (open symbol). (b) Hydrogen isotopic compositions (corrected for cosmogenic D) of olivine and silicophosphates (Si-phos) in D'Orbigny and Sahara 99555, as well as of a glass bead in D'Orbigny determined by Sarafian et al., 2017. Data from this study are shown on the right for comparison. Error bars indicate 2σ uncertainties. MI: Melt Inclusion.

## 3.2. Water content and hydrogen isotopic compositions of D'Orbigny and Sahara 99555

D'Orbigny melt inclusions and interstitial glass contain between 0.03 ± 0.01 and 5.49 ± 0.44 wt.‰ H₂O (n = 38), and glasses containing ≥0.1 wt.% water have hydrogen isotopic compositions (δD, corrected for cosmogenic D; see Section 2.4) ranging from -348 ± 53 to -118 ± 31‰ (n = 32, Fig. 5a); variations are similar in the porous and dense parts (Table S2). The water content of inclusions in Fe-rich olivine in D'Orbigny varies widely from 0.34 ± 0.02 to 5.49 ± 0.44 wt.%, whereas the most primitive melt trapped in Mg-rich olivine records a smaller concentration range of between 0.060 ± 0.001 and 1.76 ± 0.13 wt.%. Sahara 99555 inclusions contain 0.020 ± 0.001 to 1.25 ± 0.06 wt.% H₂O; a δD value of -197 ± 37‰ was obtained for the water-rich melt inclusion in Fe-rich olivine. Given that the most primitive melt trapped in Mg-rich olivine

and the most evolved melt trapped in the form of interstitial glass show comparable hydrogen isotopic compositions, there is no evidence of significant H₂ or H₂O degassing in these two volcanic angrites, in contrast to the findings of Sarafian et al., 2017. Notably, the δD values measured in this study in D'Orbigny and Sahara 99555 glasses overlap with the lowest values measured by Sarafian et al., 2017 in silicophosphates in the two angrites, whereas 'water'-poor olivine (H₂O = 7 to 18 ppm) and a glass bead (H₂O ≤ 74 ppm) appeared to be more enriched in deuterium (Fig. 5b). The unknown provenance of the glass bead analyzed previously, its unusually large size (>4 mm), its low water content, and its highly heterogeneous hydrogen isotopic composition imply that its D/H radios cannot directly be compared to those of glasses from this study.

The water content measured in the most primitive melt trapped in Mg-rich olivine in D'Orbigny (i.e., 600 ppm to
1.76 wt.% H₂O) permits to estimate the water abundance of the mantle source sampled by D'Orbigny, but, given the numerous uncertainties (i.e., mantle composition, degree of melting, 'water' partition coefficient, etc.), the calculated water content covers a wide range from 150 to 2755 ppm (see Supplementary Material; Table S4).

# 4. DISCUSSION

## 4.1. Isotopic signature and origin of volatile elements (N, H) in the APB

The N and H isotopic compositions of melt inclusions in D'Orbigny provide insight into the volatile isotopic signature of the angrite parental melt, and by inference, its source region within the APB mantle. Since Mg-rich olivine is the first mineral to form during magmatic differentiation, inclusions in this mineral record the isotopic composition of the most primitive melt (Mittlefehldt et al., 2002), provided that the melt did not experience any significant degassing prior to entrapment. Nitrogen isotopic fractionations between melt and gas were shown to be negligible in terrestrial basalts, i.e., residual melts are enriched in ¹⁵N relative to the gas by only ~1.6‰ (Cartigny et al., 2001). Although the speciation of nitrogen (N₂, NH₃) in inclusions and interstitial glass of both angrites remains unknown, due to their hydrous nature (particularly inclusions in Fe-rich olivine), they likely contain nitrogen dissolved as NH₃ (Armstrong et al., 2015; Dalou et al., 2019b; Mosenfelder et al., 2019). Open-system degassing (Rayleigh distillation) of NH₃ and N₂ will induce moderate isotopic fractionations of 70 and 40‰, respectively (Dalou et al., 2019a). Fig. 6 shows that

<figure><img src="image_7.png" /></figure>

Fig. 6. δ¹⁵N (corrected for cosmogenic ¹⁵N; see Section 2.4) as a function of the inverse of the nitrogen concentration measured in melt inclusions and interstitial glass of D'Orbigny. Trajectories for open-system (Rayleigh distillation) degassing of N₂ and NH₃ are indicated. The primitive melt (pink rectangle) is characterized by a CM-like nitrogen isotopic composition (δ¹⁵N<sub>CM</sub> = −16 to +59‰; Kerridge, 1985; Alexander et al., 2012). The more evolved melt records a contribution from a ¹⁵N-rich component. Error bars indicate 2σ uncertainties. MI: Melt Inclusion. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

the results for some inclusions in Mg-rich olivine are consistent with nitrogen loss by degassing (i.e., a wide range of nitrogen contents over a narrow range of δ¹⁵N values). Hence, only the inclusions with the lowest δ¹⁵N values and the highest N contents are assumed to be representative of the primitive, undegassed melt (Fig. 6).

The least degassed melt trapped in Mg-rich olivine of D'Orbigny (δ¹⁵N = 0 to +56‰) is more enriched in ¹⁵N than enstatite chondrites (Fig. 7a; δ¹⁵N<sub>EC</sub> = −47 to 0‰; Kung and Clayton, 1978; Grady et al., 1986) but record a nitrogen isotopic composition similar to that of CM and CI carbonaceous chondrites (δ¹⁵N<sub>CI/CM</sub> = −16 to +59‰; Kerridge, 1985; Pearson et al., 2006; Alexander et al., 2012). These findings also indicate that the δ¹⁵N signature of the APB mantle source sampled by D'Orbigny is slightly higher than the isotopic signature of nitrogen in Earth's upper mantle and crust (δ¹⁵N ≈ −40 to −5‰ in terrestrial diamonds and mid-ocean ridge basalts, δ¹⁵N ≈ +6‰ in sedimentary and crystalline rocks; Cartigny and Marty, 2013). The δD values (−348 ± 53 to −118 ± 31‰; Fig. 7a) are similar to the hydrogen isotopic signature measured in enstatite chondrites and CM carbonaceous chondrites (δD<sub>EC</sub> = −155 to −75‰ and δD<sub>CM</sub> = −226 to +126‰; Alexander et al., 2012; Piani et al., 2020), but they are significantly lower than those of CI chondrites (δD<sub>CI</sub> = +71 to +180‰; Alexander et al., 2012; Piani et al., 2020 and references therein). Furthermore, they overlap with the hydrogen isotopic compositions of ocean island basalts (δD ≥ −218‰; Deloule et al., 1991; Hallis et al., 2015), which presumably sample Earth's primitive mantle. In addition, the lowest hydrogen isotopic ratios measured in D'Orbigny agree with those of primitive silicate in eucrites, which are early-formed achondrites that originate from the Vesta 4 asteroid; the initial δD of the eucrite mantle source is estimated at −373 ± 127‰ based on the δD values measured in the least thermally metamorphosed eucrite Stannern (Stephant et al., 2021). The most D-depleted values found here and in the study of Stephant et al. (2021) hint at the presence of a nebular hydrogen component in angrite glasses and in eucrite silicates, consistent with the detection of solar-like noble gases in D'Orbigny glass (Busemann et al., 2006). However, this contribution appears to be negligible for nitrogen, as indicated by measured δ¹⁵N values that are significantly higher than the signature of nebular N (δ¹⁵N<sub>solar</sub> = −383 ± 8‰; Marty et al., 2011).

Overall, these findings imply that the APB accreted a significant amount of nitrogen and water within the first 4 Ma after CAI formation. CM carbonaceous chondrites most closely match the N-H isotopic composition of D'Orbigny's magma source, indicating that isotopically CM-like volatiles existed in the terrestrial planet-forming region in the inner solar system during its earliest history. It is noteworthy that McCubbin and Barnes (2019) also argued that a carbonaceous-chondrite like volatile reservoir might have existed in the inner solar system prior to the formation of volatile-rich carbonaceous chondrites, thus suggesting that D'Orbigny could have accreted nitrogen and hydrogen from this early-formed volatile reservoir.

Inclusions in later-formed minerals (Fe-rich olivine, anorthite, pyroxene) and interstitial glass show variable
<figure><img src="image_8.png" /><figcaption>Fig. 7. (a) δ¹⁵N versus δD of the least degassed melt trapped in Mg-rich olivine of D'Orbigny. The range of measured N (n = 7) and H (n = 4) isotope ratios in the most primitive melt in D'Orbigny is indicated by the pink rectangle. The nitrogen and hydrogen isotopic compositions of carbonaceous chondrites (CM, CI, CV, and CO), enstatite chondrites as well as Earth's mantle are shown for comparison (Kung and Clayton, 1978; Grady et al., 1986; Alexander et al., 2012; Cartigny and Marty, 2013; Peslier et al., 2017; Piani et al., 2020, and references therein). The D- and ¹⁵N-depleted solar nebula value is indicated by the yellow arrow (Geiss and Gloeckler, 1998; Marty et al., 2011). (b) δ¹⁵N versus δD of the evolved melt in D'Orbigny (i.e., interstitial glass and melt inclusions in Fe-rich olivine, anorthite, and pyroxene; red rectangle). The nitrogen and hydrogen isotopic compositions of CR carbonaceous chondrites, Jupiter-family comet (JFC), Oort cloud comets (OCCs) and the nitrogen isotopic signature of metal-rich carbonaceous chondrites (CB and CH) are shown for comparison (Table S3, Franchi et al., 1986; Sugiura et al., 2000; Pearson et al., 2006; Marty et al., 2010; Alexander et al., 2012; Piani et al., 2021 and references therein). MI: Melt Inclusion. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>

nitrogen isotopic signatures (Figs. 4 and 6), which cannot
be explained by open-system degassing (Rayleigh distilla-
tion). Another process that can account for the nitrogen
isotopic variations observed in D'Orbigny is mixing
between two reservoirs or volatile components with distinct
¹⁵N/¹⁴N ratios. Several authors have proposed that
D'Orbigny sampled two different magmas, possibly due to
the addition of a more primitive melt during crystallisation
or stirring of a heterogeneous magma (Mittlefehldt et al.,
2002; Floss et al., 2003). Consistent with this scenario, the
later phases formed show δ¹⁵N variations that probably
reflect incomplete homogenization of the residual angrite
melt with an added (unidentified) ¹⁵N-rich component.
Moreover, inclusions formed in latter phases also witness
the addition of a water-rich component (inclusions located
in Fe-rich olivine; Fig. 5a). Additionally, Hf-W and Re-Os
systematics require protracted post-core formation accre-
tion and inefficient mixing of chondritic material into the
angrite magma source (Kleine et al., 2012; Riches et al.,
2012). Mixing between two nitrogen isotopic end-
members could have occurred during the formation and
evolution of the D'Orbigny melt, and, combined with
degassing, may thus explain the variable nitrogen concen-
trations and isotopic compositions of D'Orbigny inclusions
and interstitial glass (Fig. 6). The most primitive melt is well
characterized by a CM-like end-member (Fig. 7a; δ¹⁵N ≈ 0
to +56‰), whereas the second end-member must be
enriched in ¹⁵N (δ¹⁵N > +100‰; Fig. 6). Several types of
such ¹⁵N-rich objects exist in the outer solar system
(Fig. 7b), i.e., beyond Jupiter's orbit, including CR chon-
drites (δ¹⁵N = +103 to +184‰; Pearson et al., 2006;
Alexander et al., 2012), metal-rich CB and CH chondrites

(δ¹⁵N ≥ +160 to ~ +1000‰; Franchi et al., 1986; Sugiura
et al., 2000; Marty et al., 2010), and comets (Table S3,
δ¹⁵N ~ +800‰; e.g., Bockelée-Morvan et al., 2015, and ref-
erences therein). Known CB (and possibly CH) chondrites
formed 4.6 ± 0.5 Ma after CAIs, and are likely the product
of an impact event (Weisberg et al., 2006). Hence, based on
their late timing of accretion these objects can be ruled out
as the dominant source of isotopically heavy nitrogen
observed in D'Orbigny. CR carbonaceous chondrites and
most comets are enriched in deuterium compared to the sec-
ond volatile end-member identified in D'Orbigny (Fig. 7b).
Addition of this material would, therefore, also change the
D/H ratio of the melt, unless its N/H ratio is significantly
higher than that of the primitive melt.

Overall, given the very old crystallisation age of
D'Orbigny (~4.563 Ga; Tissot et al., 2017), the nitrogen
and hydrogen isotopic signatures of olivine-hosted melt
inclusions require the presence of isotopically CM-like
volatiles in the terrestrial planet-forming region within the
first few million years of solar system history. Sahara
99555, in contrast, contains very little nitrogen and hydro-
gen, indicating that Sahara 99555 experienced more degas-
sing and/or that the two angrites did not sample the same
melt or volatile reservoir within the APB mantle.
Abernethy et al. (2013, 2018) showed that bulk nitrogen
isotopic ratios measured in D'Orbigny (δ¹⁵N up to 34.8 ±
10.7‰) are higher than in Sahara 99555 (δ¹⁵N up to 9.4 ±
3.4‰) which suggested that D'Orbigny is more degassed. In
view of the *in situ* data presented here, it seems more likely
that the ¹⁵N enrichment measured in D'Orbigny bulk rock
fragments could be the result of a contribution from a ¹⁵N-
rich component trapped in later-formed phases in the mete-
orite. It is also noteworthy that Sahara 99555 as well as five other plutonic angrites (Angra dos Reis, LEW 86010, NWA 2999, NWA 4590 and NWA 4801) record $\delta^{15}$N values between -4 and +16‰ (Abernethy et al., 2013, 2018), suggesting that multiple volatile reservoirs may have existed on the APB. These findings suggest that volatiles were heterogeneously distributed in the APB interior, and D'Orbigny may have sampled a $^{15}$N-rich domain, which is unrepresentative of the APB mantle as a whole. Finally, it should be emphasized that all angrites analyzed so far are more enriched in $^{15}$N than the mantles of Earth and Mars ($\delta^{15}$N<sub>Chassigny</sub> ~−30‰; Mathew and Marti, 2001) which could suggest that i) the relative proportion of any nitrogen contributed by nebular in-gassing is smaller in the APB, and/or ii) planetesimals in the inner solar system accreted volatile-bearing material from different sources (i.e., from different heliocentric distances).

## 4.2. Timing of volatile accretion in the inner solar system

Recent studies revealed that meteorites record a fundamental dichotomy with respect to the isotopes of refractory

(e.g., Ti, Mo) and non-refractory (e.g., Ni, Cr) elements between the so-called non-carbonaceous (NC) and carbonaceous chondrite (CC) groups, likely reflecting a heterogeneous distribution of various presolar phases in the disk (Warren, 2011; Budde et al., 2016). The two groups presumably sample parent bodies that accreted in the inner and outer solar system, respectively, and they may have been spatially separated by the rapid formation of Jupiter's core (Kruijer et al., 2017, 2020; Nanne et al., 2019; Kleine et al., 2020), a pressure maximum near the location where Jupiter later formed (Brasser and Mojzsis, 2020), or as a result of the interplay between disk dynamics and the migration of the snow line (Lichtenberg et al., 2021). The observed dichotomy implies that no substantial mixing between the NC and CC reservoirs occurred between ~1 and 4 Ma (i.e., during the formation of the meteorite parent bodies). However, this and previous studies (Abernethy et al., 2013, 2018; Sarafian et al., 2017) demonstrate that angrites (particularly D'Orbigny), which accreted very early in the NC reservoir, contain N and H that are isotopically similar to CM carbonaceous chondrites, whose parent bodies are thought to have accreted in the outer solar system beyond Jupiter's orbit.

<figure><img src="image_9.png" /><figcaption>Fig. 8. Schematic cross-section of the protoplanetary disk depicting two possible volatile accretion scenarios. (1) Early presence of isotopically CM-like N and H in the inner solar system, sunward of Jupiter's orbit, prior to the spatial separation of the NC and CC reservoirs (i.e., at ≤1 Ma; Kruijer et al., 2017). (2) Influx of volatile-rich materials from the outer solar system to the terrestrial planet-forming region ~4 Ma after CAI formation due to the growth and/or migration of Jupiter. Water-depleted materials (compared to CI chondrites), which formed inside the snowline, are indicated in red, whereas water-rich bodies, which formed beyond the snowline in cooler regions of the disk, are shown in blue. The APB (Angrite Parent Body) accreted in the inner solar system (i.e., in the NC reservoir), as indicated by its nucleosynthetic isotope composition (Trinquier et al., 2009; Warren, 2011). The so-called non-carbonaceous (NC) and carbonaceous chondrite (CC) reservoirs were presumably separated at ~1 Ma by the rapid growth of Jupiter's core (Kruijer et al., 2017) or by a pressure bump near the location at which Jupiter formed (Brasser and Mojzsis, 2020), and they coexisted until 3–4 Ma (Kruijer et al., 2017). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>
The presence of CM-like nitrogen and water in the most primitive, least degassed melt sampled by D'Orbigny (inclusions in Mg-rich olivine) may imply that carrier phases of N and H (ices, organics, and/or more refractory phases such as nitrides, for example) were already present in the inner solar system when the first planetesimals accreted (Fig. 8, upper panel; McCubbin and Barnes, 2019). The distribution of these phases was predominantly controlled by the thermal and redox conditions of the disk, and, thus, may have been decoupled from that of presolar grains (e.g., Bermingham et al., 2020). In this respect, it is important to note that the radial position of the snow line (i.e., the H₂O condensation front at ~160 K at the midplane; e.g., Lodders, 2003) changed with time as the temperature, total pressure, and density in the disk evolved, and different models place the snow line anywhere between ~1 (Sasselov and Lecar, 2000) and 3–7 AU (Cameron 1995; Boss, 1996; Dodson-Robinson et al., 2009). If the snow line migrated to ≤1 AU within the first few million years of solar system history, planetesimals in the terrestrial planet-forming region could have accreted water ice. Alternatively, experimental evaporation studies demonstrate that interstellar organic analogues remain stable at temperatures ≥350 K (Nakano et al., 2003), suggesting that such refractory organics could contribute water and other volatile elements to planetesimals that accreted sunward of the snow line (Nakano et al., 2020). Consequently, prior to the formation of the Jupiter barrier (Kruijer et al., 2017) or the establishment of a pressure bump (Brasser and Mojzsis, 2020), volatile-rich material could have been trapped inside Jupiter's orbit and delivered volatile elements to the APB (McCubbin and Barnes, 2019). Hf-W and Mn-Cr systematics indicate that the APB formed within the first ~1.5 Ma of solar system history, and its magma ocean differentiated and solidified within 3.6 ± 0.7 Ma (Kleine et al., 2012). Thus, the APB could have accreted CM-like volatiles together with refractory elements from the NC reservoir during its accretion and earliest stages of differentiation (Kleine et al., 2012; Riches et al., 2012; McCubbin and Barnes, 2019).

Nonetheless, the high $\delta^{15}$N values of the more evolved melt in D'Orbigny require a later volatile contribution from the outer solar system. Outer solar system bodies are thought to have been scattered into the terrestrial planet-forming region during the growth and/or gas-driven migration of the giant planets and the resulting destabilization of the outer disk (Raymond and Izidoro, 2017); our results suggest that this scattering must have occurred prior to the extrusion of angrite lavas ~4 Ma after CAI formation, consistent with the timescales required for dissipation of the gaseous protoplanetary disk (several million years; Raymond and Izidoro, 2017).

Alternatively, if the inner solar system remained dry for the first 3–4 Ma (consistent with models that place the snow line at ≥3 AU; e.g., Boss, 1996; Morbidelli et al., 2016), the volatile element signatures of D'Orbigny and Sahara 99555 require that isotopically CM-like and $^{15}$N-enriched materials from the outer asteroid belt and beyond were scattered sunward within a very short time after Jupiter's rapid growth or migration (Fig. 8, lower panel). The scattering

of CC-type bodies into the NC reservoir could have intermixed the different isotopic populations and provided volatile elements to the APB during the final stages of its accretion and evolution.

## 5. CONCLUSIONS

In *situ* SIMS analysis is a powerful, quasi non-destructive technique that permits to characterize the nitrogen content and isotopic composition of volatile-rich phases (e.g., melt inclusions and glass) in extraterrestrial samples. It is particularly suitable for samples that may contain nitrogen from various reservoirs (i.e., solar, chondritic and cometary) with distinct $^{15}$N/$^{14}$N ratios. To improve our understanding of the origin and evolution of nitrogen (and hydrogen) on the APB, we have applied this method, for the first time, to determine the N (and H) content and isotopic composition of melt inclusions and interstitial glass in two of the oldest angrites: D'Orbigny and Sahara 99555. Careful attention had to be paid to the possible presence of (silico-)phosphates (i.e., tsangpoite) because the $^{31}$P$^-$ peak tail can increase the $^{15}$N$^{16}$O$^-$ signal, thereby resulting in biased $\delta^{15}$N values. The most primitive (i.e., Mg-rich) melt trapped in olivine-hosted melt inclusions of D'Orbigny records $\delta^{15}$N values between 0 ± 25 to +56 ± 29‰ and $\delta$D values ranging from −348 ± 53 to −118 ± 31‰. These results indicate that the APB mantle source sampled by D'Orbigny contains isotopically CM-like volatiles, possibly with a contribution of hydrogen ingassed during the lifetime of the solar nebula, as indicated by the most D-depleted hydrogen isotope ratios. In contrast, the low nitrogen and hydrogen contents measured in Sahara 99555 could indicate that the two angrites sampled two distinct volatile reservoirs, and that D'Orbigny may have formed from a $^{15}$N-rich mantle domain within the APB. To assess the origin and distribution of nitrogen on other differentiated and primitive bodies in the solar system, it will be key to study additional meteorites as well as samples returned by space missions (e.g., Mars Sample Return, Hayabusa 2, OSIRIS-REx) using SIMS.

## CREDIT AUTHORSHIP CONTRIBUTION
STATEMENT

C. Deligny: Formal analysis, Writing - original draft, Writing - review & editing. E. Füri: Conceptualization, Project administration, Funding acquisition, Formal analysis, Writing - original draft, Writing - review & editing. Etienne Deloule: Formal analysis, Writing - original draft, Writing - review & editing.

## Declaration of Competing Interest

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.

## ACKNOWLEDGMENTS

We thank Ludovic Ferrière (Naturhistorisches Museum Wien) and Addi Bischoff (Institut für Planetologie der Westfälischen
Wihelms-Universität Münster) for providing samples of D'Orbigny and Sahara 99555, respectively. We also thank François Faure, Lionel Vacher, Yves Marrocchi, Maxime Piralla, Pierre Condamine, Sean Raymond, Nordine Bouden, Johan Villeneuve, Michel Fialin, and Nicolas Rividi for fruitful discussions, and for their assistance and support during SEM, SIMS, and EPMA analyses. Robert Dennen is acknowledged for English editing. Constructive comments by associate editor Audrey Bouvier, Seann McKibbin and two anonymous reviewers helped to improve this manuscript. This work was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 715028). This is CRPG contribution 2789.

## APPENDIX A. SUPPLEMENTARY MATERIAL

Supplementary data to this article can be found online at https://doi.org/10.1016/j.gca.2021.07.038.

## REFERENCES

* Abernethy F. A. J., Verchovsky A. B., Starkey N. A., Anand M., Franchi I. A. and Grady M. M. (2013) Stable isotope analysis of carbon and nitrogen in angrites. *Meteorit. Planet. Sci.* **48**, 1590–1606.

* Abernethy F. A. J., Verchovsky A. B., Franchi I. A. and Grady M. M. (2018) Basaltic volcanism on the angrite parent body: comparison with 4 Vesta. *Meteorit. Planet. Sci.* **53**, 375–393.

* Alexander C. O. D., Bowden R., Fogel M. L., Howard K. T., Herd C. D. K. and Nittler L. R. (2012) The provenances of asteroids, and their contributions to the volatile inventories of the terrestrial planets. *Science* **337**, 721–723.

* Alexander C. M. O. D. (2017) The origin of inner Solar System water. *Philos. Tr. R. Soc. A* **375**, 20150384.

* Armstrong L. S., Hirschmann M. M., Stanley B. D., Falksen E. G. and Jacobsen S. D. (2015) Speciation and solubility of reduced C-O-H-N volatiles in mafic melt: implications for volcanism, atmospheric evolution, and deep volatile cycles in the terrestrial planets. *Geochim. Cosmochim. Acta* **171**, 283–302.

* Bermingham K. L., Füri E., Lodders K. and Marty B. (2020) The NC-CC isotope dichotomy: implications for the chemical and isotopic evolution of the early solar system. *Space Sci. Rev.* **216**, 1–29.

* Bischoff A., Clayton R. N., Markl G., Mayeda T. K., Palme H., Schultz L., Srinivasan G., Weber H. W., Weckwerth G. and Wolf D. (2000) Mineralogy, chemistry, noble gases, and oxygen-and magnesium-isotopic compositions of the angrite Sahara 99555. *Meteorit. Planet. Sci. Supplement* **35**, A27.

* Bockelée-Morvan D., Calmonte U., Charnley S., Duprat J., Engrand C., Gicquel A., Hässig M., Jehin E., Kawakita H., Marty B. and Milam S. (2015) Cometary isotopic measurements. *Space Sci. Rev.* **197**, 47–83.

* Boss A. P. (1996) Evolution of the solar nebula. III. Protoplanetary disks undergoing mass accretion. *Astrophys. J.* **469**, 906–920.

* Bouliung J., Füri E., Dalou C., Tissandier L., Zimmermann L. and Marrocchi Y. (2020) Oxygen fugacity and melt composition controls on nitrogen solubility in silicate melts. *Geochim. Cosmochim. Acta* **284**, 120–133.

* Brasser R. and Mojzsis S. J. (2020) The partitioning of the inner and outer Solar System by a structured protoplanetary disk. *Nature Astronomy* **4**, 492–499.

* Budde G., Burkhardt C., Brennecka G. A., Fischer-Gödde M., Kruijer T. S. and Kleine T. (2016) Molybdenum isotopic evidence for the origin of chondrules and a distinct genetic

* heritage of carbonaceous and non-carbonaceous meteorites. *Earth Planet. Sc. Lett.* **454**, 293–303.

* Busemann H., Lorenzetti S. and Eugster O. (2006) Noble gases in D'Orbigny, Sahara 99555 and D'Orbigny glass—evidence for early planetary processing on the angrite parent body. *Geochim. Cosmochim. Acta* **70**, 5403–5425.

* Cameron A. G. W. (1995) The first ten million years in the solar nebula. *Meteoritics* **30**, 133–161.

* Cartigny P., Jendrzejewski N., Pineau F., Petit E. and Javoy M. (2001) Volatile (C, N, Ar) variability in MORB and the respective roles of mantle source heterogeneity and degassing: the case of the Southwest Indian Ridge. *Earth Planet. Sci. Lett.* **194**, 241–257.

* Cartigny P. and Marty B. (2013) Nitrogen isotopes and mantle geodynamics: the emergence of life and the atmosphere–crust–mantle connection. *Elements* **9**, 359–366.

* Dalou C., Füri E., Deligny C., Piani L., Caumon M. C., Laumonier M., Bouliung J. and Edén M. (2019a) Redox control on nitrogen isotope fractionation during planetary core formation. *Proc. Natl. Acad. Sci.* **116**, 14485–14494.

* Dalou C., Hirschmann M. M., Jacobsen S. D. and Le Losq C. (2019b) Raman spectroscopy study of COHN speciation in reduced basaltic glasses: implications for reduced planetary mantles. *Geochim. Cosmochim. Acta* **265**, 32–47.

* Dauphas N. (2017) The isotopic nature of the Earth's accreting material through time. *Nature* **541**, 521.

* Deloule E., Albarede F. and Sheppard S. M. (1991) Hydrogen isotope heterogeneities in the mantle from ion probe analysis of amphiboles from ultramafic rocks. *Earth Planet. Sci. Lett.* **105**, 543–553.

* Day J. M. and Moynier F. (2014) Evaporative fractionation of volatile stable isotopes and their bearing on the origin of the Moon. *Philos. Tr. R. Soc. A* **372**, 20130259.

* Dodson-Robinson S. E., Willacy K., Bodenheimer P., Turner N. J. and Beichman C. A. (2009) Ice lines, planetesimal composition and solid surface density in the solar nebula. *Icarus* **200**, 672–693.

* Floss C., Crozaz G., McKay G., Mikouchi T. and Killgore M. (2003) Petrogenesis of angrites. *Geochim. Cosmochim. Acta* **67**, 4775–4789.

* Franchi I. A., Wright I. P. and Pillinger C. T. (1986) Heavy nitrogen in Bencubbin—a light-element isotopic anomaly in a stony-iron meteorite. *Nature* **323**, 138–140.

* Füri E. and Marty B. (2015) Nitrogen isotope variations in the Solar System. *Nat. Geosci.* **8**, 515.

* Füri E., Deloule E. and Trappitsch R. (2017) The production rate of cosmogenic deuterium at the Moon's surface. *Earth Planet. Sci. Lett.* **474**, 76–82.

* Füri E., Deloule E. and Dalou C. (2018) Nitrogen abundance and isotope analysis of silicate glasses by secondary ionization mass spectrometry. *Chem. Geol.* **493**, 327–337.

* Füri E., Zimmermann L., Deloule E. and Trappitsch R. (2020) Cosmic ray effects on the isotope composition of hydrogen and noble gases in lunar samples: insights from Apollo 12018. *Earth Planet. Sci. Lett.* **550** 116550.

* Geiss J. and Gloeckler G. (1998) Abundances of deuterium and helium-3 in the protosolar cloud. *Primordial Nuclei and their Galactic evolution*, 239–250.

* Grady M. M., Wright I. P., Carr L. P. and Pillinger C. T. (1986) Compositional differences in enstatite chondrites based on carbon and nitrogen stable isotope measurements. *Geochim. Cosmochim. Acta* **50**, 2799–2813.

* Hallis L. J., Huss G. R., Nagashima K., Taylor G. J., Halldórsson S. A., Hilton D. R., Mottl M. J. and Meech K. J. (2015) Evidence for primordial water in Earth's deep mantle. *Science* **350**, 795–797.
Hashizume K., Marty B. and Wieler R. (2002) Analyses of nitrogen and argon in single lunar grains: towards a quantification of the asteroidal contribution to planetary surfaces. *Earth Planet. Sci. Lett.* **202**, 201–216.

Irving A. J. and Kuehner S. M. (2007) Plutonic angrite NWA 4801 and a model for the angrite parent body consistent with petrological and chronological constraints. *Chronol. Meteorites Early Solar System* **1374**, 74–75.

Javoy M., Pineau F. and Delorme H. (1986) Carbon and nitrogen isotopes in the mantle. *Chem. Geol.* **57**, 41–62.

Keil K. (2012) Angrites, a small but diverse suite of ancient, silica-undersaturated volcanic-plutonic mafic meteorites, and the history of their parent asteroid. *Chem. Erde-Geochem.* **72**, 191–218.

Kerridge J. F. (1985) Carbon, hydrogen and nitrogen in carbonaceous chondrites: abundances and isotopic compositions in bulk samples. *Geochim. Cosmochim. Acta* **49**, 1707–1714.

Kleine T., Hans U., Irving A. J. and Bourdon B. (2012) Chronology of the angrite parent body and implications for core formation in protoplanets. *Geochim. Cosmochim. Acta* **84**, 186–203.

Kleine T., Budde G., Burkhardt C., Kruijer T. S., Worsham E. A., Morbidelli A. and Nimmo F. (2020) The non-carbonaceous–carbonaceous meteorite dichotomy. *Space Sci. Rev.* **216**, 1–27.

Kruijer T. S., Burkhardt C., Budde G. and Kleine T. (2017) Age of Jupiter inferred from the distinct genetics and formation times of meteorites. *Proc. Natl. Acad. Sci.* **114**, 6712–6716.

Kruijer T. S., Kleine T. and Borg L. E. (2020) The great isotopic dichotomy of the early Solar System. *Nature Astron.*, **1–9.

Kung C. C. and Clayton R. N. (1978) Nitrogen abundances and isotopic compositions in stony meteorites. *Earth Planet. Sci. Lett.* **38**, 421–435.

Kurat G., Brandstätter F., Clayton R., Nazarov M. A., Palme H., Schultz L., Varela M. E., Wäsch E., Weber H. W. and Weckwerth G. (2001) D'Orbigny: A new and unusual angrite. *Lunar Planet. Sci.* XXXII. Lunar Planet. Inst., Houston. #1753 (abstr.).

Kurat G., Varela M. E., Brandstätter F., Weckwerth G., Clayton R. N., Weber H. W., Schultz L., Wäsch E. and Nazarov M. A. (2004) D'Orbigny: a non-igneous angritic achondrite? *Geochim. Cosmochim. Acta* **68**, 1901–1921.

Lichtenberg T., Dąrżkowska J., Schönbächler M., Golabek G. J. and Hands T. O. (2021) Bifurcation of planetary building blocks during Solar System formation. *Science* **371**, 365–370.

Lodders K. (2003) Solar system abundances and condensation temperatures of the elements. *Astrophys. J.* **591**, 1220–1247.

Loewen M. W., Graham D. W., Bindeman I. N., Lupton J. E. and Garcia M. O. (2019) Hydrogen isotopes in high ³He/⁴He submarine basalts: primordial vs. recycled water and the veil of mantle enrichment. *Earth Planet. Sci. Lett.* **508**, 62–73.

Marty B., Kelley S. and Turner G. (2010) Chronology and shock history of the Bencubbin meteorite: a nitrogen, noble gas, and Ar–Ar investigation of silicates, metal and fluid inclusions. *Geochim. Cosmochim. Acta* **74**, 6636–6653.

Marty B., Chaussidon M., Wiens R. C., Jurewicz A. J. G. and Burnett D. S. (2011) A ¹⁵N-poor isotopic composition for the solar system as shown by Genesis solar wind samples. *Science* **332**, 1533–1536.

Mathew K. J. and Marti K. (2001) Early evolution of Martian volatiles: nitrogen and noble gas components in ALH84001 and Chassigny. *J. Geophys. Res.-Planet* **106**, 1401–1422.

McCoy T. J., Wilson L., Benedix G. K. and Ketcham R. A. (2003) Vesicles in meteorites: the angle on angrites. *Meteoritics Planet. Sci. Suppl.* **38**, 5115.

McCoy T. J., Ketcham R. A., Wilson L., Benedix G. K., Wadhwa M. and Davis A. M. (2006) Formation of vesicles in asteroidal basaltic meteorites. *Earth Planet. Sci. Lett.* **246**, 102–108.

McCubbin F. M. and Barnes J. J. (2019) Origin and abundances of H₂O in the terrestrial planets, Moon, and asteroids. *Earth Planet. Sci. Lett.* **526** 115771.

Métrich N. and Deloule E. (2014) Water content, δD and δ¹¹B tracking in the Vanuatu arc magmas (Aoba Island): insights from olivine-hosted melt inclusions. *Lithos* **206**, 400–408.

Mikouchi T., McKay G. and Le L. (2000) A new angrite Sahara 99555: Mineralogical comparison with Angra dos Reis, Lewis Cliff 86010, Lewis Cliff 87051, and Asuka 881371 angrites. *Antarctic Meteorites* XXV **25**, 74–76.

Mikouchi T. and McKay G. (2001) Mineralogical Investigation of D'Orbigny: A New Angrite Showing Close Affinities to Asuka 881371, Sahara 99555, and Lewis Cliff 87051. *Lunar Planet. Sci.* XXXII. Lunar Planet. Inst., Houston. #1876 (abstr.).

Mittlefehldt D. W., Killgore M. and Lee M. T. (2002) Petrology and geochemistry of D'Orbigny, geochemistry of Sahara 99555, and the origin of angrites. *Meteorit. Planet. Sci.* **37**, 345–369.

Morbidelli A., Lambrechts M., Jacobson S. and Bitsch B. (2015) The great dichotomy of the Solar System: small terrestrial embryos and massive giant planet cores. *Icarus* **258**, 418–429.

Morbidelli A., Bitsch B., Crida A., Gounelle M., Guillot T., Jacobson S., Johansen A., Lambrechts M. and Lega E. (2016) Fossilized condensation lines in the Solar System protoplanetary disk. *Icarus* **267**, 368–376.

Mosenfelder J. L., Von Der Handt A., Füri E., Dalou C., Hervig R. L., Rossman G. R. and Hirschmann M. M. (2019) Nitrogen incorporation in silicates and metals: results from SIMS, EPMA, FTIR, and laser-extraction mass spectrometry. *Am. Mineral.* **104**, 31–46.

Nakano H., Kouchi A., Tachibana S. and Tsuchiyama A. (2003) Evaporation of interstellar organic materials in the solar nebula. *Astrophys. J.* **592**, 1252.

Nakano H., Hirakawa N., Matsubara Y., Yamashita S., Okuchi T., Asahina K., Tanaka R., Suzuki N., Naraoka H., Takano Y. and Tachibana S. (2020) Precometary organic matter: a hidden reservoir of water inside the snow line. *Sci. Rep-UK* **10**, 1–13.

Nanne J. A., Nimmo F., Cuzzi J. N. and Kleine T. (2019) Origin of the non-carbonaceous–carbonaceous meteorite dichotomy. *Earth Planet. Sci. Lett.* **511**, 44–54.

Nyquist L. and Bogard D. D. (2003) Isotopic studies of basaltic meteorites: constraints on the size and thermal history of differentiated asteroids. In *Symp. on Evolution of Solar System Materials: A new Perspective from Antarct. Meteorites*, NIPR.

O'Neill H. S. C. and Palme H. (2008) Collisional erosion and the non-chondritic composition of the terrestrial planets. *Philos. Tr. R. Soc. A* **366**, 4205–4238.

Pearson V. K., Sephton M. A., Franchi I. A., Gibson J. M. and Gilmour I. (2006) Carbon and nitrogen in carbonaceous chondrites: elemental abundances and stable isotopic compositions. *Meteorit. Planet. Sci.* **41**, 1899–1918.

Peslier A. H., Schönbächler M., Busemann H. and Karato S. I. (2017) Water in the Earth's interior: distribution and origin. *Space Sci. Rev.* **212**, 743–810.

Piani L., Marrocchi Y., Rigaudier T., Vacher L. G., Thomassin D. and Marty B. (2020) Earth's water may have been inherited from material similar to enstatite chondrite meteorites. *Science* **369**, 1110–1113.

Piani L., Marrocchi Y., Vacher L. G., Yurimoto H. and Bizzarro M. (2021) Origin of hydrogen isotopic variations in chondritic water and organics. *Earth Planet. Sci. Lett.* **567** 117008.

Raymond S. N. and Izidoro A. (2017) Origin of water in the inner Solar System: planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion. *Icarus* **297**, 134–148.

Reedy R. C. (1981) Cosmic-ray produced stable nuclides: various production rates and their implications. *Proc. Lunar Sci. Conf.* **12B**, 1809–1823.
Riches A. J., Day J. M., Walker R. J., Simonetti A., Liu Y., Neal C. R. and Taylor L. A. (2012) Rhenium–osmium isotope and highly-siderophile-element abundance systematics of angrite meteorites. *Earth Planet. Sci. Lett.* **353**, 208–218.

Sanborn M. E. and Wadhwa M. (2021) Trace element geochemistry of coarse-grained angrites from Northwest Africa: implications for their petrogenesis on the angrite parent body. *Meteorit. Planet. Sci* **56**, 482–499.

Sarafian A. R., Nielsen S. G., Marschall H. R., McCubbin F. M. and Monteleone B. D. (2014) Early accretion of water in the inner solar system from a carbonaceous chondrite–like source. *Science* **346**, 623–626.

Sarafian A. R., Hauri E. H., McCubbin F. M., Lapen T. J., Berger E. L., Nielsen S. G., Marschall H. R., Gaetani G. A., Righter K. and Sarafian E. (2017) Early accretion of water and volatile elements to the inner Solar System: evidence from angrites. *Philos. Tr. R. Soc. A* **375**, 20160209.

Sasselov D. D. and Lecar M. (2000) On the snow line in dusty protoplanetary disks. *Astrophys. J.* **528**, 995–998.

Schiller M., Connelly J. N., Glad A. C., Mikouchi T. and Bizzarro M. (2015) Early accretion of protoplanets inferred from a reduced inner solar system $^{26}$Al inventory. *Earth Planet. Sci. Lett.* **420**, 45–54.

Stephant A., Wadhwa M., Hervig R., Bose M., Zhao X., Barrett T. J., Anand M. and Franchi I. A. (2021) A deuterium-poor water reservoir in the asteroid 4 Vesta and the inner solar system. *Geochim. Cosmochim. Acta* **297**, 203–219.

Sugiura N., Zashu S., Weisberg M. and Prinz M. (2000) A nitrogen isotope study of bencubbinites. *Meteorit. Planet. Sci.* **35**, 987–996.

Tissot F. L., Dauphas N. and Grove T. L. (2017) Distinct $^{238}$U/$^{235}$U ratios and REE patterns in plutonic and volcanic angrites: geochronologic implications and evidence for U isotope fractionation during magmatic processes. *Geochim. Cosmochim. Acta* **213**, 593–617.

Trinquier A., Elliott T., Ulfbeck D., Coath C., Krot A. N. and Bizzarro M. (2009) Origin of nucleosynthetic isotope heterogeneity in the solar protoplanetary disk. *Science* **324**, 374–376.

Varela M. E., Kurat G., Zinner E., Metrich N., Brandstätter F., Ntaflos T. and Sylvester P. (2003) Glasses in the D'Orbigny angrite. *Geochim. Cosmochim. Acta* **67**, 5027–5046.

Warren P. H. (2011) Stable-isotopic anomalies and the accretionary assemblage of the Earth and Mars: a subordinate role for carbonaceous chondrites. *Earth Planet. Sci. Lett.* **311**, 93–100.

Weisberg M. K., Kimura M., Suzuki A., Ohtani E. and Sugiura N. (2006) Discovery of coesite and significance of high pressure phases in the Gujba CB chondrite. In Proc. Lunar Sci. Conf. p. 1788.

Zhu K., Moynier F., Wielandt D., Larsen K. K., Barrat J. A. and Bizzarro M. (2019) Timing and origin of the angrite parent body inferred from Cr isotopes. *Astrophys. J. Lett.* **877**, L13.

Associate editor: Audrey Bouvier