Fassaite composition trends during crystallization of Allende Type B refractory inclusion melts

doi:10.1016/0016-7037(91)90379-J

Geochimica et Cosmochimica Acta

Volume 55, Issue 9, September 1991, Pages 2635-2655

https://doi.org/10.1016/0016-7037(91)90379-J Get rights and content

Abstract

Fassaite is a major phase in Type B refractory inclusions and its wide compositional variability makes it an excellent recorder of crystallization-induced changes in liquid composition. Traverses across zoned crystals with electron and ion microprobes show that Ti, V, Sc, Zr and Hf decrease from core to rim, while Mg, Si, REEs, and other trace elements increase. Fassaite/liquid distribution coefficients derived from the compositions of early fassaite and calculated parent liquid compositions are higher than previously reported fassaite Ds, e.g., 0.2–0.8 vs. 0.08–0.5 for the trivalent REEs, possibly due to the high Ti and Al contents of the fassaite we analyzed. Log-log plots of concentrations of elements vs. those of Sc give linear relationships with slopes of $(D ̄_{i}^{xl/L} − 1)/(D ̄_{Sc}^{xl/L} − 1)$ , where $D ̄_{i}^{xl/L}$ - is the bulk crystal/liquid distribution coefficient for element i. From this relationship, we derive effective fassaite/liquid Ds of 2.8 for Sc, 1.5 for Hf, 1.1 for Zr, 0.52 for Y, 0.34 for Ta, 0.29 for Nb, and 0.31–0.48 for trivalent REEs. The effective Ds are applicable to fassaite crystallizing from melts having the compositions and thermal histories of Allende Type B refractory inclusions, and incorporate any equilibrium and kinetic effects that modify Ds during the course of crystallization. Observed fassaite REE contents can be reproduced by a fractional crystallization model in which the effective Ds are used. Ti³⁺ is more compatible in fassaite than Ti⁴⁺ and, without equilibration of the residual liquid with an external reducing gas, $Ti^{3+} Ti^{tot}$ ratios (where Ti^tot = Ti³⁺ + Ti⁴⁺ should decrease from core to rim in fassaite crystals. Comparison of profiles of Ti³⁺Ti^tot ratios in several crystals with those calculated for fractional crystallization suggests that the trend in one crystal was controlled by fractional crystallization alone, but in two others the virtually constant $Ti^{3+} Ti^{tot}$ ratios may imply that the liquids in these inclusions were able to maintain equilibrium with the solar nebular gas throughout crystallization. Attempts to determine the $ƒ_{o_{2}}$ of fassaite crystallization on the basis of $Ti^{3+} Ti^{tot}$ ratios must be based on fassaite grains which are not zoned with respect to $Ti^{3+} Ti^{tot}$ . The range of observed REE abundances in subliquidus fassaite (7–800 × Cl for La and 30–2000 × Cl for Lu) now encompasses those in grains previously identified as relict, removing a major reason for their identification as such. Rounded fassaite grains with fairly sharp Mg-rich rims and Ti-rich cores, poikilitically enclosed in mantle melilite in TS34 are candidates for relict grains. The grains are so Scrich that they would require extreme prior crystallization of spinel and melilite, which is inconsistent with their very low REE contents (e.g., La at 3–7 × Cl). We suggest that the cores of these grains are relict and were trapped with liquid during formation of the mantle.

References (48)

E. Anders et al.
Abundances of the elements: Meteoritic and solar
Geochim. Cosmochim. Acta
(1989)
D.J. Barber et al.
The microstructures of minerals in coarse-grained Ca-Al-rich inclusions from the Allende meteorite
Geochim. Cosmochim. Acta
(1984)
J.R. Beckett et al.
Crystal chemical effects on the partitioning of trace elements between mineral and melt: An experimental study of melilite with applications to refractory inclusions from carbonaceous chondrites
Geochim. Cosmochim. Acta
(1990)
T. Benjamin et al.
Actinide crystal-liquid partitioning for clinopyroxene and Ca₃(PO₄)₂
Geochim. Cosmochim. Acta
(1980)
W.V. Boynton
Fractionation in the solar nebula: Condensation of yttrium and the rare earth elements
Geochim. Cosmochim. Acta
(1975)
R.N. Clayton et al.
Distribution of the pre-solar component in Allende and other carbonaceous chondrites
Earth Planet. Sci. Lett.
(1977)
G. Crozaz et al.
Rare earth elements in Angra dos Reis and Lewis Cliff 86010, two meteorites with similar but distinct magma evolutions
Earth Planet. Sci. Lett.
(1990)
A.M. Davis et al.
Condensation and fractionation of rare earths in the solar nebula
Geochim. Cosmochim. Acta
(1979)
A.M. Davis et al.
Melt solidification and late-stage evaporation in the evolution of a FUN inclusion from the Vigarano C3V chondrite
Geochim. Cosmochim. Acta
(1991)
M.J. Drake et al.
New rare earth element standards for electron microprobe analysis
Chem. Geol.
(1972)

A. El Goresy et al.

Anatomy of an Allende coarse-grained inclusion

Geochim. Cosmochim. Acta

(1985)

L. Grossman

Condensation in the primitive solar nebula

Geochim. Cosmochim. Acta

(1972)

L. Grossman

Petrography and mineral chemistry of Ca-rich inclusions in the Allende meteorite

Geochim. Cosmochim. Acta

(1975)

L. Grossman et al.

Trace elements in the Allende meteorite—I. Coarse-grained, Ca-rich inclusions

Geochim. Cosmochim. Acta

(1976)

L. Grossman et al.

Trace elements in the Allende meteorite—III. Coarse-grained inclusions revisited

Geochim. Cosmochim. Acta

(1977)

R.M. Hazen et al.

Crystal structure and compositional variation of Angra dos Reis fassaite

Earth Planet. Sci. Lett.

(1977)

R.W. Hinton et al.

A chemical and isotopic study of hibonite-rich refractory inclusions in primitive meteorites

Geochim. Cosmochim. Acta

(1988)

S.M. Kuehner et al.

Determination of trace element mineral/liquid partition coefficients in melilite and diopside by ion and electron microprobe techniques

Geochim. Cosmochim. Acta

(1989)

G.J. MacPherson et al.

A once-molten, coarsegrained, Ca-rich inclusion in Allende

Earth Planet. Sci. Lett.

(1981)

G.J. MacPherson et al.

The evolution of a complex type B Allende inclusion: An ion microprobe trace element study

Geochim. Cosmochim. Acta

(1989)

B. Mason et al.

Minor and trace element distribution in melilite and pyroxene from the Allende meteorite

Earth Planet. Sci. Lett.

(1974)

G. McKay et al.

Clinopyroxene REE distribution coefficients for shergottites: The REE content of the Shergotty melt

Geochim. Cosmochim. Acta

(1986)

M.T. Murrell et al.

Actinide chemistry in Allende Ca-Al-rich inclusions

Geochim. Cosmochim. Acta

(1987)

H. Nagasawa et al.

Experimental mineral/liquid partition coefficients of the rare earth elements (REE), Sc and Sr for perovskite, spinel and melilite

Earth Planet. Sci. Lett.

(1980)

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On the nature of oxygen-isotope heterogeneity of igneous calcium-aluminum-rich inclusions in cv carbonaceous chondrites
2022, Geochimica et Cosmochimica Acta
Coarse-grained igneous Ca,Al-rich inclusions (CAIs) in CV (Vigarano group) carbonaceous chondrites have typically heterogeneous O-isotope compositions with melilite, anorthite, and high-Ti (>10 wt% TiO₂) fassaite being ¹⁶O-depleted (Δ¹⁷O up to ∼ − 3 ± 2‰) compared to hibonite, spinel, low-Ti (<10 wt% TiO₂) fassaite, Al-diopside, and forsterite, all having close-to-solar Δ¹⁷O ∼ − 24 ± 2‰. To test a hypothesis that this heterogeneity was established, at least partly, during aqueous fluid-rock interaction, we studied the mineralogy, petrology, and O-isotope compositions of igneous CAIs CG-11 (Type B), TS-2F-1, TS-68, and 818-G (Compact Type A), and 818-G-UR (davisite-rich) from Allende (CV > 3.6), and E38 (Type B) from Efremovka (CV3.1–3.4). Some of these CAIs contain (i) eutectic mineral assemblages of melilite, Al,Ti-diopside, and ± spinel which co-crystallized and therefore must have recorded O-isotope composition of the eutectic melt; (ii) isolated inclusions of Ti-rich fassaite inside spinel grains which could have preserved their initial O-isotope compositions, and/or (iii) pyroxenes of variable chemical compositions which could have recorded gas–melt O-isotope exchange during melt crystallization and/or postcrystallization exchange controlled by O-isotope diffusivity. If these CAIs experienced isotopic exchange with an aqueous fluid, O-isotope compositions of some of their primary minerals are expected to approach that of the fluid.
We find that in the eutectic melt regions composed of highly-åkermanitic melilite (Åk₆₅₋₇₁), anorthite, low-Ti fassaite, and spinel of E38, spinel, fassaite, and anorthite are similarly ¹⁶O-rich (Δ¹⁷O ∼ − 24‰), whereas melilite is ¹⁶O-poor (Δ¹⁷O ∼ − 1‰). In the eutectic melt regions of CG-11, spinel and low-Ti fassaite are ¹⁶O-rich (Δ¹⁷O ∼ − 24‰), whereas melilite and anorthite are ¹⁶O-poor (Δ¹⁷O ∼ − 3‰). In TS-2F-1, TS-68, and 818-G, melilite and high-Ti fassaite grains outside spinel have ¹⁶O-poor compositions (Δ¹⁷O range from − 12 to − 3‰); spinel is ¹⁶O-rich (Δ¹⁷O ∼ − 24‰); perovskite grains show large variations in Δ¹⁷O, from − 24 to − 1‰. Some coarse perovskites are isotopically zoned with a ¹⁶O-rich core and a ¹⁶O-poor edge. Isolated high-Ti fassaite inclusions inside spinel grains are ¹⁶O-rich (Δ¹⁷O ∼ − 24‰), whereas high-Ti fassaite inclusions inside fractured spinel grains are ¹⁶O-depleted: Δ¹⁷O range from − 12 to − 3‰. In 818-G-UR, davisite is ¹⁶O-poor (Δ¹⁷O ∼ − 2‰), whereas Al-diopside of the Wark-Lovering rim is ¹⁶O-enriched (Δ¹⁷O < − 16‰). On a three-isotope oxygen diagram, the ¹⁶O-poor melilite, anorthite, high-Ti fassaite, and davisite in the Allende CAIs studied plot close to O-isotope composition of an aqueous fluid (Δ¹⁷O ∼ − 3 ± 2‰) inferred from O-isotope compositions of secondary minerals resulted from metasomatic alteration of the Allende CAIs.
We conclude that CV igneous CAIs experienced post-crystallization O-isotope exchange that most likely resulted from an aqueous fluid-rock interaction on the CV asteroid. It affected melilite, anorthite, high-Ti fassaite, perovskite, and davisite, whereas hibonite, spinel, low-Ti fassaite, Al-diopside, and forsterite retained their original O-isotope compositions established during igneous crystallization of CV CAIs. However, we cannot exclude some gas–melt O-isotope exchange occurred in the solar nebula. This apparently “mineralogically-controlled” exchange process was possibly controlled by variations in oxygen self-diffusivity of CAI minerals. Experimentally measured oxygen self-diffusion coefficients in CAI-like minerals are required to constrain relative roles of O-isotope exchange during aqueous fluid–solid and nebular gas–melt interaction.
The formation of Type B CAIs: Evolution from Type A CAIs
2022, Geochimica et Cosmochimica Acta
Five Type A CAIs from three CV3 chondrites (Vigarano, Northwest Africa 3118, Allende), which differ in age by no more than ∼10⁵ years, show mineralogical and textural evidence of gradual transition into Type Bs, indicating that Type B inclusions formed by evolution of Type A CAIs in the solar nebula. This model differs from the conventional condensation model in which aggregates of condensate grains form different kinds of CAIs depending on the relative populations of different kinds of grains. In our model the pyroxene forms nearly isochemically by reaction of perovskite with melilite under highly reducing conditions. Anorthite requires the addition of silica from the gas, and originally forms as veins and reaction rims on gehlenitic melilite within Fluffy Type As. Later partial re-melting of these assemblages results in the formation of poikilitic pyroxene and anorthite that enclose rounded (partially melted) tablets of melilite. Oxygen isotopes in four of the CAIs support the formation of Ti-rich ¹⁶O-depleted pyroxene from ¹⁶O-depleted perovskite, but not in the fifth CAI. An alternative possibility is that Ti-rich ¹⁶O-depleted pyroxene is the result of later solid-state exchange that preferentially affects the most Ti-rich pyroxene. Regardless of the origin of the ¹⁶O-depleted pyroxene, we give a model for nebular reservoir evolution based on sporadic FU-Orionis flare-ups in which the ¹⁶O-rich region near the proto-Sun fluctuated in size depending on whether the proto-Sun was in flare-up stage or quiescent.
Origin of minerals in åkermanite-rich patch texture and oxygen isotopic evolution of compact Type A Ca-Al-rich inclusions from the Northwest Africa 7865 CV chondrite
2021, Geochimica et Cosmochimica Acta
We report the in-situ oxygen isotopic distributions corresponding to the petrographic-mineralogical observation on a compact Type A (CTA) Ca-Al-rich inclusion (CAI), KU-N-02, from a reduced CV3 chondrite, Northwest Africa 7865. The CTA has an igneous texture and mainly consists of spinel, melilite, and Al-Ti-rich clinopyroxene (fassaite). Oxygen isotopic compositions of the constituent minerals plot along the carbonaceous chondrite anhydrous mineral line. The spinel grains are poikilitically enclosed in the melilite and fassaite and are uniformly ¹⁶O-rich (Δ¹⁷O = approximately − 23‰). The fassaite is texturally classified into two types: blocky fassaite and intergranular fassaite. The blocky fassaite crystals exhibit growth zoning as they change from Ti-rich to Ti-poor along the inferred directions of crystal growth from core to rim, while the oxygen isotopic compositions change from ¹⁶O-poor (Δ¹⁷O = approximately − 6‰) to ¹⁶O-rich (Δ¹⁷O = approximately − 23‰) with crystal growth. The intergranular fassaite crystals exist between the melilite crystals and exhibit variable Ti abundance and oxygen isotopic compositions. Additionally, their relationships between Ti contents and oxygen isotopic composition are similar to those of the blocky fassaite. The melilite grains are homogeneously ¹⁶O-poor (Δ¹⁷O = approximately − 2‰), irrespective of their åkermanite (Åk) content. Each melilite grain generally exhibits growth zoning with increasing Åk contents from core to rim, although the melilite contains Åk-rich patches within single crystal. Åk-rich patches often include two types of fassaite: small blebby crystals attached to spinel crystals and round crystals. The oxygen isotopic compositions of the Åk-rich patch and blebby fassaite are ¹⁶O-poor (Δ¹⁷O = approximately − 2‰), similar to that of the host melilite. On the other hand, the round fassaite exhibits significant variation in oxygen isotopic compositions ranging from Δ¹⁷O = −23‰ to − 4‰, which are different from those of the host melilite. These petrographic textures and oxygen isotopic variations indicate the presence of a solid precursor with variable oxygen isotopic compositions for the CTA. The spinel and round fassaite grains are relicts of the precursor that melted in the ¹⁶O-poor nebular gas, resulting in the crystallization of the host melilite from the ¹⁶O-poor melt. The Åk-rich patches and blebby fassaite crystallized from melts trapped by the growing host melilite crystals. The blocky and intergranular fassaite crystallized after the melilite did, and the oxygen isotopic composition of the melt changed to ¹⁶O-rich during the crystallization process, suggesting that the oxygen isotopic composition of the surrounding nebular gas could be varied. The inferred oxygen isotopic evolution for CTA is consistent with those inferred for Type B CAIs, suggesting that coarse-grained igneous CAIs formed in a similar nebular environment regardless of precursor chemistry.
Warkite, Ca<inf>2</inf>Sc<inf>6</inf>Al<inf>6</inf>O<inf>20</inf>, a new mineral in carbonaceous chondrites and a key-stone phase in ultrarefractory inclusions from the solar nebula
2020, Geochimica et Cosmochimica Acta
Citation Excerpt :
By considering the phase assemblages and the partitioning of Sc and other refractory elements among these phases, one can, in principle, place direct constraints on the origin and evolution of the constituent phases. Scandium is a minor to trace element in fassaitic pyroxene (e.g., Simon and Grossman, 1991), which is the major host phase for Sc in most CAIs. It is also a trace to minor element in highly refractory phases such as hibonite and perovskite (Ireland et al., 1988; Ivanova et al., 2012) but it can also be a structurally essential constituent.
Warkite (IMA 2013-129) is a new Sc-rich ultrarefractory mineral in the rhönite group of the sapphirine supergroup. It has a P $\bar{1}$ aenigmatite-type structure with a = 10.367 Å, b = 10.756 Å, c = 8.895 Å, α = 106°, β = 96°, γ = 125°, and Z = 2, and general formula of Ca₂(Sc,Ti,Al,Mg,Zr)₆Al₆O₂₀. Warkite occurs as micrometer-sized crystals in eleven ultrarefractory Ca,Al-rich inclusions (UR CAIs) from the CM, CV, CO, and CH chondrites. In the CM, CO, and CV CAIs, warkite in the cores coexists with a Ti-rich oxide, either perovskite or kangite; the cores are generally mantled and rimmed by davisite and/or Sc-diopside. In the CH CAIs and one CO CAI, warkite in the cores coexists with perovskite and grossite; the cores are mantled by grossite ± gehlenite, and rimmed by low-Sc, Al-diopside. Therefore, there are two basic families of warkite-bearing inclusions, those containing Sc-rich clinopyroxene but no grossite and those containing grossite but no Sc-rich clinopyroxene. Scandian clinopyroxene in warkite-bearing CAIs generally formed by the reaction of warkite, which supplied most or all of the Sc, Ti, and Al, and a nebular gas that supplied much of the Ca and O and virtually all of the Mg and Si. The presence of Sc-rich clinopyroxenes may reflect exposure of some warkite-bearing CAIs to a dust-rich environment, which would enhance partial pressures of Si-, Mg-, and Ca-bearing species in the vapor and make it oxidizing relative to a dust-poor gas. Warkite in grossite-bearing inclusions is generally Ti³⁺-enriched relative to those in davisite-bearing inclusions, consistent with their formation in relatively dust-poor, more-reducing environments. Warkite compositions are sensitive to the presence or absence of spinel, melilite, Sc-rich clinopyroxenes, and grossite. Compositional variations of perovskite and warkite grains indicate a connection but, except for late-stage Fe exchange, they did not equilibrate with each other. The presence of at least two trends in Y-Sc among perovskites without corresponding trends in warkite suggests that at least some perovskite formed separately.
Warkite-bearing CAIs from CM2s and CO3.0s are uniformly ¹⁶O-rich (Δ¹⁷O ∼ −23‰), whereas those from metamorphosed COs and CVs are isotopically heterogeneous: warkite, kangite, perovskite, melilite, and davisite are ¹⁶O-depleted to various degrees (Δ¹⁷O range from −22 to −2‰) relative to hibonite, spinel, and forsterite, all having ¹⁶O-rich compositions (Δ¹⁷O ∼  − 25 to −20‰). We infer that warkite-bearing CAIs originated in an ¹⁶O-rich nebular gas. Subsequently, CAIs from metamorphosed CVs and COs experienced O-isotope exchange with an ¹⁶O-depleted external reservoir, most likely aqueous fluids on the CV and CO chondrite parent asteroids; however, O-isotope exchange in the solar nebula cannot be excluded.
Oxybarometry and valence quantification based on microscale X-ray absorption fine structure (XAFS) spectroscopy of multivalent elements
2020, Chemical Geology
Citation Excerpt :
The fact that substantial trivalent Ti is present in the mafic silicates of ureilite Y-791538 strongly suggests that these phases have a strong preference for this reduced species. In a study of Ti3+ zoning in fassaite (Ti-rich pyroxene) in the Allende carbonaceous chondrite, Simon et al. (1991) noted that a factor of three preference for Ti3+ would explain the observed zonation. This value is supported by a crystallization experiment of an L6 chondrite composition melt at IW-3.7 which showed a ratio of 3.2 (Simon et al., 2014).
X-ray absorption fine structure (XAFS) spectroscopy has proven to be a valuable tool in defining valence states of multivalent elements in minerals and glasses that can then be used as oxybarometry proxies. First row transition multivalent elements Ti, V, Cr, and Fe are common targets. Micro-XAFS provides wide coverage of oxygen fugacity on all minerals and glasses, with high spatial resolution, trace level sensitivity, and no stoichiometry constraints. This method has been applied to an extensive array of geochemical problems including heterogeneity of terrestrial mantle sources, effects of volatile degassing of magmas, evolution of lunar melts, metamorphism of chondrites, and relationships between achondrites. Valence states alone can be insightful indicators of oxidation, such as the presence or absence of Ti³⁺ and the effects of metamorphism on asteroidal parent bodies. Importantly, XAFS can be extended to infer oxygen fugacity of parent melts by calibrating with laboratory experiment products under controlled conditions. When valence measurements or oxygen fugacity determinations are undertaken on non-cubic minerals, careful calibration data using oriented samples as well as knowledge of valence-specific partition coefficients are needed. XAFS offers the ability to apply multiple oxybarometers (e.g., Ti, Cr, and V valence proxies) to individual, potentially zoned, mineral grains. Challenges include corrections for orientation effects, X-ray beam-induced modifications, and the sparcity of valence-specific partition coefficient measurements. In some cases, application of statistical and machine-learning methods based on linear algebra such as principal component analysis (PCA), partial least-squares (PLS) analysis, and least absolute shrinkage and selection operator (Lasso) regressions can help to identify and compensate for some of external factors complicating XAFS analysis.
Nebular history of an ultrarefractory phase bearing CAI from a reduced type CV chondrite
2019, Geochimica et Cosmochimica Acta
Ultrarefractory (UR) phases in calcium-aluminum-rich inclusions (CAIs) could have formed at higher temperature compared to common CAI minerals and thus they potentially provide constraints on very high temperature processes in the solar nebula. We report a detailed characterization of the mineralogy, petrology and oxygen isotopic composition of an UR phase davisite (CaScAlSiO₆) bearing CAI from a reduced type CV chondrite. The CAI is an irregular-shaped, compound inclusion that consists of five units that are composed of melilite + spinel + Al,Ti-rich pyroxene  $\pm$  perovskite with various modal abundances of minerals and lithologies, and surrounded by the Wark-Lovering (WL) rim. Davisite occurs only in one lithological unit that consists of three chemically and isotopically distinct parts: (i) $^{16}$ O-poor ( $- 20 ‰ ⩽ δ^{18} O ⩽ 0 ‰$ ) regions with reversely-zoned melilite and davisite; (ii) $^{16}$ O-rich ( $- 50 ‰ ⩽ δ^{18} O ⩽ - 40 ‰$ ) regions consisting of unzoned, gehlenitic melilite, Al,Ti-rich diopside and spinel; and (iii) spinel framboids composed of $^{16}$ O-rich spinel and $^{16}$ O-poor melilite. Absence of secondary iron- and/or alkali-rich phases, occurrence of low-iron, manganese-enriched (LIME) olivine, and random distribution of the oxygen isotopic heterogeneity indicate that primitive chemical and isotopic compositions are preserved in the inclusion. The occurrence of chemical and isotopic heterogeneities with sharp boundaries in the CAI indicates formation of the inclusion by an aggregation of mineral assemblages formed and processed separately at different time and/or space in the solar nebula. Although isotope exchange between $^{16}$ O-rich solids and $^{16}$ O-poor gases prior to the final agglomeration of the CAI cannot be ruled out, we suggest that modification of chemical and isotopic composition of porous CAI precursors or aggregation of isotopically distinct mineral assemblages are alternative scenarios for the origin of oxygen isotopic heterogeneity in CAIs. In either case, coexistence of spatially and/or temporally distinct $^{16}$ O-rich and $^{16}$ O-poor gaseous reservoirs at the earliest stage of the solar system formation is required. The grain-scale oxygen isotopic disequilibrium in the CAI indicate that post-formation heating of the inclusion (i.e., the WL rim formation event) was short (e.g., $≲ 10^{3}$  h at 1400 K; $≲ 10^{5}$  h at 1100 K), which can be achieved by rapid outward transport of the CAI. High Ti³⁺/Ti^tot ratios of pyroxene from CAI interior and the rim and LIME composition of the olivine rim document that the entire CAI formation process took place under highly reducing conditions.

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Fassaite composition trends during crystallization of Allende Type B refractory inclusion melts

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