[ { "id": "authors:xyq9t-s6e35", "collection": "authors", "collection_id": "xyq9t-s6e35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230209-988069100.15", "type": "article", "title": "SIMS relative sensitivity factors for Al/Mg in synthetic and Madagascar hibonite", "author": [ { "family_name": "MacPherson", "given_name": "G. J.", "clpid": "MacPherson-G-J" }, { "family_name": "Beckett", "given_name": "J.", "clpid": "Beckett-J" }, { "family_name": "Kita", "given_name": "N. T.", "clpid": "Kita-N-T" }, { "family_name": "Nagashima", "given_name": "K.", "clpid": "Nagashima-K" }, { "family_name": "Krot", "given_name": "A. N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-Alexander-N" }, { "family_name": "Fournelle", "given_name": "J.", "clpid": "Fournelle-J" }, { "family_name": "K\u00f6\u00f6p", "given_name": "L.", "clpid": "K\u00f6\u00f6p-L" }, { "family_name": "Hertwig", "given_name": "A. T.", "clpid": "Hertwig-A-T" }, { "family_name": "Rose", "given_name": "T. R.", "clpid": "Rose-T-R" }, { "family_name": "Davis", "given_name": "A. M.", "clpid": "Davis-A-M" } ], "abstract": "We synthesized three compositions of hibonite, differing in their levels of MgO and TiO\u2082 that were chosen to cover most of the range of compositions of natural meteoritic hibonite. The goal was to evaluate the appropriateness of the use of terrestrial Madagascar hibonite as a standard in the SIMS analysis of initial \u00b2\u2076Al/\u00b2\u2077Al ratios in calcium\u2011aluminum-rich inclusions, and especially its use for the determination of the \u00b2\u2077Al/\u00b2\u2074Mg relative sensitivity factor (RSF). Concern exists because of the high levels of FeO and rare earth elements (REE) in the terrestrial mineral relative to meteoritic samples. Our results show that, provided the specific Madagascar hibonite samples in a given lab are carefully characterized in terms of mineral chemistry (including Fe, Th, and REE) via electron microprobe analysis, the terrestrial mineral gives RSFs that are within 2% of those determined for the synthetic samples. The \u00b2\u2077Al/\u00b2\u2074Mg SIMS/EPMA RSF based on the synthetic hibonite compositions alone is 0.779 \u00b1 0.003; combining all synthetic and Madagascar hibonite analyses yields a RSF of 0.777 \u00b1 0.003. We cannot rule out that RSFs might be somewhat different using different SIMS instruments, or among individual SIMS sessions, so RSFs should be evaluated for each SIMS session.", "doi": "10.1016/j.chemgeo.2022.121272", "issn": "0009-2541", "publisher": "Elsevier", "publication": "Chemical Geology", "publication_date": "2023-02-05", "volume": "617", "pages": "Art. No. 121272" }, { "id": "authors:1w8yq-tmw41", "collection": "authors", "collection_id": "1w8yq-tmw41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190816-103122788", "type": "article", "title": "Mineralogy, Petrography, and Oxygen Isotopic Compositions of Ultrarefractory Inclusions from Carbonaceous Chondrites", "author": [ { "family_name": "Krot", "given_name": "A. N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-A-N" }, { "family_name": "Ma", "given_name": "C.", "orcid": "0000-0002-1828-7033", "clpid": "Ma-Chi-Geology" }, { "family_name": "Nagashima", "given_name": "K.", "clpid": "Nagashima-Kazuhide" }, { "family_name": "Davis", "given_name": "A. M.", "clpid": "Davis-A-M" }, { "family_name": "Beckett", "given_name": "J. R.", "clpid": "Beckett-J-R" }, { "family_name": "Simon", "given_name": "S. B.", "clpid": "Simon-S-B" }, { "family_name": "Komatsu", "given_name": "M.", "clpid": "Komatsu-M" }, { "family_name": "Fagan", "given_name": "T. J.", "clpid": "Fagan-T-J" }, { "family_name": "Brenker", "given_name": "F.", "clpid": "Brenker-F" }, { "family_name": "Ivanova", "given_name": "M. A.", "clpid": "Ivanova-M-A" }, { "family_name": "Bischoff", "given_name": "A.", "clpid": "Bischoff-A" } ], "abstract": "We report on the mineralogy, petrography, and in situ oxygen isotopic composition of twenty-five ultrarefractory calcium-aluminum-rich inclusions (UR CAIs) in CM2, CR2, CH3.0, CV3.1\u20153.6, CO3.0\u20153.6, MAC 88107 (CO3.1-like), and Acfer 094 (C3.0 ungrouped) carbonaceous chondrites. The UR CAIs studied are typically small, < 100 \u00b5m in size, and contain, sometimes dominated by, Zr-, Sc-, and Y-rich minerals, including allendeite (Sc_4Zr_3O_(12)), and an unnamed ((Ti,Mg,Sc,Al)_3O_5) mineral, davisite (CaScAlSiO_6), eringaite (Ca_3(Sc,Y,Ti)_2Si_3O_(12)), kangite ((Sc,Ti,Al,Zr,Mg,Ca,\u25a1)_2O_3), lakargiite (CaZrO_3), warkite (Ca_2Sc_6Al_6O_(20)), panguite ((Ti,Al,Sc,Mg,Zr,Ca)_(1.8)O_3), Y-rich perovskite ((Ca,Y)TiO_3), tazheranite ((Zr,Ti,Ca)O_(2\u2015x)), thortveitite (Sc_2Si_2O_7), zirconolite (orthorhombic CaZrTi_2O_7), and zirkelite (cubic CaZrTi_2O_7). These minerals are often associated with 50\u2015200 nm-sized nuggets of platinum group elements. The UR CAIs occur as: (i) individual irregularly-shaped, nodular-like inclusions; (ii) constituents of unmelted refractory inclusions \u2013 amoeboid olivine aggregates (AOAs) and Fluffy Type A CAIs; (iii) relict inclusions in coarse-grained igneous CAIs (forsterite-bearing Type Bs and compact Type As); and (iv) relict inclusions in chondrules. Most UR CAIs, except for relict inclusions, are surrounded by single or multilayered Wark-Lovering rims composed of Sc-rich clinopyroxene, \u00b1eringaite, Al-diopside, and \u00b1forsterite. Most of UR CAIs in carbonaceous chondrites of petrologic types 2\u20153.0 are uniformly ^(16)O-rich (\u0394^(17)O \u02dc \u201523\u2030), except for one CH UR CAI, which is uniformly ^(16)O-depleted (\u0394^(17)O \u02dc \u20155\u2030). Two UR CAIs in Murchison have heterogeneous \u039417O. These include: an intergrowth of corundum (\u02dc \u201224\u2030) and (Ti,Mg,Sc,Al)_3O_5 (\u02dc 0\u2030), and a thortveitite-bearing CAI (\u02dc \u201220 to \u02dc \u20125\u2030); the latter apparently experienced incomplete melting during chondrule formation. In contrast, most UR CAIs in metamorphosed chondrites are isotopically heterogeneous (\u0394^(17)O ranges from \u02dc \u201523\u2030 to \u02dc \u20152\u2030), with Zr- and Sc-rich oxides and silicates, melilite and perovskite being ^(16)O-depleted to various degrees relative to uniformly ^(16)O-rich (\u0394^(17)O \u02dc \u201523\u2030) hibonite, spinel, Al-diopside, and forsterite. We conclude that UR CAIs formed by evaporation/condensation, aggregation and, in some cases, melting processes in a ^(16)O-rich gas of approximately solar composition in the CAI-forming region(s), most likely near the protoSun, and were subsequently dispersed throughout the protoplanetary disk. One of the CH UR CAIs formed in an ^(16)O-depleted gaseous reservoir providing an evidence for large variations in \u0394^(17)O of the nebular gas in the CH CAIs-forming region. Subsequently some UR CAIs experienced oxygen isotopic exchange during melting in ^(16)O-depleted regions of the disk, most likely during the epoch of chondrule formation. In addition, UR CAIs in metamorphosed CO and CV chondrites, and, possibly, the corundum-(Ti,Mg,Sc,Al)_3O_5 intergrowth in Murchison experienced O-isotope exchange with aqueous fluids on the CO, CV, and CM chondrite parent asteroids. Thus, both nebular and planetary exchange with ^(16)O-depleted reservoirs occurred.", "doi": "10.1016/j.chemer.2019.07.001", "issn": "0009-2819", "publisher": "Elsevier", "publication": "Geochemistry", "publication_date": "2019-12", "series_number": "4", "volume": "79", "issue": "4", "pages": "Art. No. 125519" }, { "id": "authors:wqnqv-a1d03", "collection": "authors", "collection_id": "wqnqv-a1d03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190816-104059727", "type": "article", "title": "Mineralogy, Petrography, and Oxygen and Aluminum-Magnesium Isotope Systematics of Grossite-Bearing Refractory Inclusions", "author": [ { "family_name": "Krot", "given_name": "Alexander N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-A-N" }, { "family_name": "Nagashima", "given_name": "Kazuhide", "clpid": "Nagashima-Kazuhide" }, { "family_name": "Simon", "given_name": "Steven B.", "clpid": "Simon-S-B" }, { "family_name": "Ma", "given_name": "Chi", "orcid": "0000-0002-1828-7033", "clpid": "Ma-Chi-Geology" }, { "family_name": "Connolly", "given_name": "Harold C., Jr.", "clpid": "Connolly-H-C-Jr" }, { "family_name": "Huss", "given_name": "Gary R.", "orcid": "0000-0003-4281-7839", "clpid": "Huss-G-R" }, { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Bizzarro", "given_name": "Martin", "clpid": "Bizzarro-M" } ], "abstract": "Grossite (CaAl_4O_7) is one of the one of the first minerals predicted to condense from a gas of solar composition, and therefore could have recorded isotopic compositions of reservoirs during the earliest stages of the Solar System evolution. Grossite-bearing Ca,Al-rich inclusions (CAIs) are a relatively rare type of refractory inclusions in most carbonaceous chondrite groups, except CHs, where they are dominant. We report new and summarize the existing data on the mineralogy, petrography, oxygen and aluminum-magnesium isotope systematics of grossite-bearing CAIs from the CR, CH, CB, CM, CO, and CV carbonaceous chondrites. Grossite-bearing CAIs from unmetamorphosed (petrologic type 2\u20153.0) carbonaceous chondrites preserved evidence for heterogeneous distribution of ^(26)Al in the protoplanetary disk. The inferred initial ^(26)Al/^(27)Al ratio [(^(26)Al/^(27)Al)_0] in grossite-bearing CAIs is generally bimodal, \u02dc0 and \u02dc5\u00d710^(\u20125); the intermediate values are rare. CH and CB chondrites are the only groups where vast majority of grossite-bearing CAIs lacks resolvable excess of radiogenic ^(26)Mg. Grossite-bearing CAIs with approximately the canonical (^(26)Al/^(27)Al)_0 of \u02dc5\u00d710^(\u20125) are dominant in other chondrite groups. Most grossite-bearing CAIs in type 2\u20123.0 carbonaceous chondrites have uniform solar-like O-isotope compositions (\u0394^(17)O \u02dc \u201224\u00b12\u2030). Grossite-bearing CAIs surrounded by Wark-Lovering rims in CH chondrites are also isotopically uniform, but show a large range of \u0394^(17)O, from \u02dc \u201240\u2030 to \u02dc \u20125\u2030, suggesting an early generation of gaseous reservoirs with different oxygen-isotope compositions in the protoplanetary disk. Igneous grossite-bearing CAIs surrounded by igneous rims of \u00b1melilite, Al-diopside, and Ca-rich forsterite, found only in CB and CH chondrites, have uniform ^(16)O-depleted compositions (\u0394^(17)O \u02dc \u201214\u2030 to \u20125\u2030). These CAIs appear to have experienced complete melting and incomplete O-isotope exchange with a ^(16)O-poor (\u0394^(17)O \u02dc \u20122\u2030) gas in the CB impact plume generated about 5 Ma after CV CAIs. Grossite-bearing CAIs in metamorphosed (petrologic type >3.0) CO and CV chondrites have heterogeneous \u0394^(17)O resulted from mineralogically-controlled isotope exchange with a ^(16)O-poor (\u0394^(17)O \u02dc \u20122 to 0\u2030) aqueous fluid on the CO and CV parent asteroids 3\u20125 Ma after CV CAIs. This exchange affected grossite, krotite, melilite, and perovskite; corundum, hibonite, spinel, diopside, forsterite, and enstatite preserved their initial O-isotope compositions. The internal ^(26)Al-^(26)Mg isochrons in grossite-bearing CAIs from weakly-metamorphosed CO and CV chondrites were not disturbed during this oxygen-isotope exchange.", "doi": "10.1016/j.chemer.2019.08.001", "issn": "0009-2819", "publisher": "Elsevier", "publication": "Geochemistry", "publication_date": "2019-12", "series_number": "4", "volume": "79", "issue": "4", "pages": "Art. No. 125529" }, { "id": "authors:ceqbt-76n37", "collection": "authors", "collection_id": "ceqbt-76n37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190709-103021676", "type": "article", "title": "Mineralogy, Petrography, and Oxygen Isotopic Compositions of Ultrarefractory Inclusions from Carbonaceous Chondrites", "author": [ { "family_name": "Krot", "given_name": "A. N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-A-N" }, { "family_name": "Ma", "given_name": "C.", "orcid": "0000-0002-1828-7033", "clpid": "Ma-Chi-Geology" }, { "family_name": "Nagashima", "given_name": "K.", "clpid": "Nagashima-K" }, { "family_name": "Davis", "given_name": "A. M.", "clpid": "Davis-A-M" }, { "family_name": "Beckett", "given_name": "J. R.", "clpid": "Beckett-J-R" }, { "family_name": "Simon", "given_name": "S. B.", "clpid": "Simon-S-B" }, { "family_name": "Komatsu", "given_name": "M.", "clpid": "Komatsu-M" }, { "family_name": "Fagan", "given_name": "T. J.", "clpid": "Fagan-T-J" }, { "family_name": "Genzel", "given_name": "P. T.", "clpid": "Genzel-P-T" }, { "family_name": "Brenker", "given_name": "F.", "clpid": "Brenker-F" }, { "family_name": "Ivanova", "given_name": "M. A.", "clpid": "Ivanova-M-A" }, { "family_name": "Bischoff", "given_name": "A.", "clpid": "Bischoff-A" } ], "abstract": "Fine-grained CAIs with Group II rare earth element (REE) patterns condensed from a gaseous reservoir from which the ultrarefractory (UR) REEs had been removed. The carriers of UR REEs are poorly known. Here we report on the mineralogy, petrography and O-isotope compositions of 25 CAIs, presumably UR (REEs have not yet measured), from CR2, CM2, C3.0, CO3.0\u20123.6, CV3.1\u20123.6, and CH3.0 carbonaceous chondrites (CCs).", "doi": "10.1111/maps.13346", "issn": "1086-9379", "publisher": "Meteoritical Society", "publication": "Meteoritics and Planetary Science", "publication_date": "2019-08", "series_number": "S2", "volume": "54", "issue": "S2", "pages": "6109" }, { "id": "authors:5r09d-0x687", "collection": "authors", "collection_id": "5r09d-0x687", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180613-152623011", "type": "article", "title": "Titanium isotopes and rare earth patterns in CAIs: Evidence for thermal processing and gas-dust decoupling in the protoplanetary disk", "author": [ { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Zhang", "given_name": "Junjun", "clpid": "Zhang-Junjun" }, { "family_name": "Greber", "given_name": "Nicolas D.", "clpid": "Greber-N-D" }, { "family_name": "Hu", "given_name": "Jingya", "clpid": "Hu-Jingya" }, { "family_name": "Tissot", "given_name": "Fran\u00e7ois L. H.", "orcid": "0000-0001-6622-2907", "clpid": "Tissot-F-L-H" }, { "family_name": "Dauphas", "given_name": "Nicolas", "orcid": "0000-0002-1330-2038", "clpid": "Dauphas-N" } ], "abstract": "Titanium isotopic compositions (mass-dependent fractionation and isotopic anomalies) were measured in 46 calcium-, aluminum-rich inclusions (CAIs) from the Allende CV chondrite. After internal normalization to ^(49)Ti/^(47)Ti, we found that \u03b5^(50)Ti values are somewhat variable among CAIs, and that \u03b5^(46)Ti is highly correlated with \u03b5^(50)Ti, with a best-fit slope of 0.162 \u00b1 0.030 (95% confidence interval). The linear correlation between \u03b5^(46)Ti and \u03b5^(50)Ti extends the same correlation seen among bulk solar objects (slope 0.184 \u00b1 0.007). This observation provides constraints on dynamic mixing of the solar disk and has implications for the nucleosynthetic origin of titanium isotopes, specifically on the possible contributions from various types of supernovae to the solar system. Titanium isotopic mass fractionation, expressed as \u03b4\u2032^(49)Ti, was measured by both sample-standard bracketing and double-spiking. Most CAIs are isotopically unfractionated, within a 95% confidence interval of normal, but a few are significantly fractionated and the range \u03b4\u2032^(49)Ti is from \u223c\u22124 to \u223c+4. Rare earth element patterns were measured in 37 of the CAIs. All CAIs with significant titanium mass fractionation effects have group II and related REE patterns, implying kinetically controlled volatility fractionation during the formation of these CAIs.", "doi": "10.1016/j.gca.2017.07.032", "issn": "0016-7037", "publisher": "Elsevier", "publication": "Geochimica et Cosmochimica Acta", "publication_date": "2018-01-15", "volume": "221", "pages": "275-295" }, { "id": "authors:vfnsq-pqp16", "collection": "authors", "collection_id": "vfnsq-pqp16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141219-112703384", "type": "article", "title": "Calcium-48 isotopic anomalies in bulk chondrites and achondrites: Evidence for a uniform isotopic reservoir in the inner protoplanetary disk", "author": [ { "family_name": "Dauphas", "given_name": "Nicolas", "orcid": "0000-0002-1330-2038", "clpid": "Dauphas-N" }, { "family_name": "Chen", "given_name": "James H.", "clpid": "Chen-James-H" }, { "family_name": "Zhang", "given_name": "Junjun", "clpid": "Zhang-Junjun" }, { "family_name": "Papanastassiou", "given_name": "Dimitri A.", "clpid": "Papanastassiou-D-A" }, { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Travaglio", "given_name": "Claudia", "clpid": "Travaglio-C" } ], "abstract": "Thermal ionization mass spectrometry (TIMS) was used to measure the calcium isotopic compositions of carbonaceous, ordinary, enstatite chondrites as well as eucrites and aubrites. We find that after correction for mass-fractionation by internal normalization to a fixed ^(42)Ca/^(44)Ca ratio, the ^(43)Ca/^(44)Ca and ^(46)Ca/^(44)Ca ratios are indistinguishable from terrestrial ratios. In contrast, the ^(48)Ca/^(44)Ca ratios show significant departure from the terrestrial composition (from \u22122 \u03b5 in eucrites to +4 \u03b5 in CO and CV chondrites). Isotopic anomalies in \u03b5^(48)Ca correlate with \u03b5 ^(50)Ti \u03b5^(48)Ca=(1.09\u00b10.11)\u00d7\u03b5^(50)Ti+(0.03\u00b10.14). Further work is needed to identify the carrier phase of ^(48)Ca\u2013^(50)Ti anomalies but we suggest that it could be perovskite and that the stellar site where these anomalies were created was also responsible for the nucleosynthesis of the bulk of the solar system inventory of these nuclides. The Earth has identical ^(48)Ca isotopic composition to enstatite chondrites (EH and EL) and aubrites. This adds to a long list of elements that display nucleosynthetic anomalies at a bulk planetary scale but show identical or very similar isotopic compositions between enstatite chondrites, aubrites, and Earth. This suggests that the inner protoplanetary disk was characterized by a uniform isotopic composition (IDUR for Inner Disk Uniform Reservoir), sampled by enstatite chondrites and aubrites, from which the Earth drew most of its constituents. The terrestrial isotopic composition for ^(17)O, ^(48)Ca, ^(50)Ti, ^(62)Ni, and ^(92)Mo is well reproduced by a mixture of 91% enstatite, 7% ordinary, and 2% carbonaceous chondrites. The Earth was not simply made of enstatite chondrites but it formed from the same original material that was later modified by nebular and disk processes. The Moon-forming impactor probably came from the same region as the other embryos that made the Earth, explaining the strong isotopic similarity between lunar and terrestrial rocks.", "doi": "10.1016/j.eps1.2014.09.015", "issn": "0012-821X", "publisher": "Elsevier", "publication": "Earth and Planetary Science Letters", "publication_date": "2014-12-01", "volume": "407", "pages": "96-108" }, { "id": "authors:fgb9c-10f33", "collection": "authors", "collection_id": "fgb9c-10f33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141219-130341226", "type": "article", "title": "Calcium-aluminum-rich inclusions with fractionation and unknown nuclear effects (FUN CAIs): I. Mineralogy, petrology, and oxygen isotopic compositions", "author": [ { "family_name": "Krot", "given_name": "Alexander N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-A-N" }, { "family_name": "Nagashima", "given_name": "Kazuhide", "clpid": "Nagashima-K" }, { "family_name": "Wasserburg", "given_name": "Gerald J.", "orcid": "0000-0002-7957-8029", "clpid": "Wasserburg-G-J" }, { "family_name": "Huss", "given_name": "Gary R.", "orcid": "0000-0003-4281-7839", "clpid": "Huss-G-R" }, { "family_name": "Papanastassiou", "given_name": "Dimitri A.", "clpid": "Papanastassiou-D-A" }, { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Hutcheon", "given_name": "Ian D.", "clpid": "Hutcheon-I-D" }, { "family_name": "Bizzarro", "given_name": "Martin", "clpid": "Bizzarro-M" } ], "abstract": "We present a detailed characterization of the mineralogy, petrology, and oxygen isotopic compositions of twelve FUN CAIs, including C1 and EK1-4-1 from Allende (CV), that were previously shown to have large isotopic fractionation patterns for magnesium and oxygen, and large isotopic anomalies of several elements. The other samples show more modest patterns of isotopic fractionation and have smaller but significant isotopic anomalies. All FUN CAIs studied are coarse-grained igneous inclusions: Type B, forsterite-bearing Type B, compact Type A, and hibonite-rich. Some inclusions consist of two mineralogically distinct lithologies, forsterite-rich and forsterite-free/poor. All the CV FUN CAIs experienced postcrystallization open-system iron-alkali-halogen metasomatic alteration resulting in the formation of secondary minerals commonly observed in non-FUN CAIs from CV chondrites. The CR FUN CAI GG#3 shows no evidence for alteration. In all samples, clear evidence of oxygen isotopic fractionation was found. Most samples were initially ^(16)O-rich. On a three-oxygen isotope diagram, various minerals in each FUN CAI (spinel, forsterite, hibonite, dmisteinbergite, most fassaite grains, and melilite (only in GG#3)), define mass-dependent fractionation lines with a similar slope of \u223c0.5. The different inclusions have different \u0394^(17)O values ranging from \u223c\u221225\u2030 to \u223c\u221216\u2030. Melilite and plagioclase in the CV FUN CAIs have ^(16)O-poor compositions (\u0394^(17)O \u223c\u22123\u2030) and plot near the intercept of the Allende CAI line and the terrestrial fractionation line. We infer that mass-dependent fractionation effects of oxygen isotopes in FUN CAI minerals are due to evaporation during melt crystallization. Differences in \u0394^(17)O values of mass-dependent fractionation lines defined by minerals in individual FUN CAIs are inferred to reflect differences in \u0394^(17)O values of their precursors. Differences in \u03b4^(18)O values of minerals defining the mass-dependent fractionation lines in several FUN CAIs are consistent with their inferred crystallization sequence, suggesting these minerals crystallized during melt evaporation. In other FUN CAIs, no clear correlation between \u03b4^(18)O values of individual minerals and their inferred crystallization sequence is observed, possibly indicating gas-melt back reaction and oxygen-isotope exchange in a ^(16)O-rich gaseous reservoir. After oxygen-isotope fractionation, some FUN CAIs could have experienced partial melting and gas-melt oxygen-isotope exchange in a ^(16)O-poor gaseous reservoir that resulted in crystallization of ^(16)O-depleted fassaite, melilite and plagioclase. The final oxygen isotopic compositions of melilite and plagioclase in the CV FUN CAIs may have been established on the CV parent asteroid as a result of isotope exchange with a ^(16)O-poor fluid during hydrothermal alteration. \nWe conclude that FUN CAIs are part of a general family of refractory inclusions showing various degrees of fractionation effects due to evaporative processes superimposed on sampling of isotopically heterogeneous material. These processes have been experienced both by FUN and non-FUN igneous CAIs. Generally, the inclusions identified as FUN show larger isotope fractionation effects than non-FUN CAIs. There is a wide spread in UN isotopic anomalies in a large number of CAIs not exhibiting large fractionation effects in oxygen, magnesium, and silicon. The question of why some FUN CAIs show more extreme UN isotopic effects is attributed by us to limited sampling and not a special source of isotopically anomalous material. We consider the majority of igneous CAIs to be the result of several stages of thermal processing (evaporation, condensation, and melting) of aggregates of solid precursors composed of incompletely isotopically homogenized materials. The unknown nuclear effects in CAIs are common to both FUN and non-FUN CAIs, and are not a special characteristic of FUN inclusions but represent the spectrum of results from sampling a very heterogeneous medium in the accreting Solar System.", "doi": "10.1016/j.gca.2014.09.027", "issn": "0016-7037", "publisher": "Elsevier", "publication": "Geochimica et Cosmochimica Acta", "publication_date": "2014-11-15", "volume": "145", "pages": "206-247" }, { "id": "authors:mj3rw-02g28", "collection": "authors", "collection_id": "mj3rw-02g28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131206-093814685", "type": "article", "title": "Heterogeneity of Mg Isotopes and Variable ^(26)Al/^(27)Al Ratio in FUN CAIs", "author": [ { "family_name": "Park", "given_name": "C.", "clpid": "Park-C" }, { "family_name": "Nagashima", "given_name": "K.", "clpid": "Nagashima-K" }, { "family_name": "Hutcheon", "given_name": "I. D.", "clpid": "Hutcheon-I-D" }, { "family_name": "Wasserburg", "given_name": "G. J.", "orcid": "0000-0002-7957-8029", "clpid": "Wasserburg-G-J" }, { "family_name": "Papanastassiou", "given_name": "D. A.", "clpid": "Papanastassiou-D-A" }, { "family_name": "Davis", "given_name": "A. M.", "clpid": "Davis-A-M" }, { "family_name": "Huss", "given_name": "G. R.", "orcid": "0000-0003-4281-7839", "clpid": "Huss-G-R" }, { "family_name": "Krot", "given_name": "A. N.", "orcid": "0000-0002-2278-8519", "clpid": "Krot-A-N" } ], "abstract": "CAIs with fractionation and unidentified nuclear effects (FUN CAIs) are characterized by low initial ^(26)Al/^(27)Al ratios, large mass-dependent fractionation in Mg (F_(Mg)), Si, and O isotopes, and nucleosynthetic anomalies in several elements (e.g., Ca, Ti). Most Mg-isotope studies of FUN CAIs were performed more than 30 years ago with TIMS. Here we report high-precision Mg-isotope data of individual minerals from the Axtell 2271, BG82DH8, EK1-4-1, C1, TE, and CG14 FUN CAIs measured with the UH Cameca ims-1280. We followed the procedure described in [2]. Measured Mg-isotope data were correct-ed for fractionation using terrestrial standards assuming that their isotopic compositions are the same as values of [3], and an exponential law with a coefficient \u03b2 = 0.514. The overall conclusions of this study do not change with the choice of \u03b2.", "doi": "10.1111/maps.12165", "issn": "1086-9379", "publisher": "Meteoritical Society", "publication": "Meteoritics and Planetary Science", "publication_date": "2013-07", "series_number": "S1", "volume": "48", "issue": "S1", "pages": "A277" }, { "id": "authors:awmye-kyn22", "collection": "authors", "collection_id": "awmye-kyn22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150427-112242771", "type": "article", "title": "Experimental studies of trace element partitioning in Ca, Al-rich compositions: Anorthite and perovskite", "author": [ { "family_name": "Simon", "given_name": "S. B.", "clpid": "Simon-S-B" }, { "family_name": "Kuehner", "given_name": "S. M.", "clpid": "Kuehner-S-M" }, { "family_name": "Davis", "given_name": "A. M.", "clpid": "Davis-A-M" }, { "family_name": "Grossman", "given_name": "L.", "clpid": "Grossman-L" }, { "family_name": "Johnson", "given_name": "M. L.", "clpid": "Johnson-M-L" }, { "family_name": "Burnett", "given_name": "D. S.", "orcid": "0000-0001-9521-8675", "clpid": "Burnett-D-S" } ], "abstract": "Using electron probe and ion probe techniques, experimental crystal-liquid partition coefficients (D) have been measured in meteoritic Ca,Al-rich inclusion (CAI) compositions for Mg, Zr, Y, and REEs in anorthite and perovskite. Partitioning data for Ti in anorthite and Al in perovskite are also reported. Where cross-comparisons are possible between electron and ion probe data, agreement is good. Concentration variations in anorthite for many elements are beyond what can be explained by fractional crystallization, but show well-defined interelement correlations which could reflect the temperature dependence of the D values or could result from liquid boundary layers. For anorthite our D values for REEs are lower, and they decrease more rapidly with decreasing ionic radius than most in the literature. Most of the older REE D patterns for plagioclase in the literature are too flat because of insufficient purity of mineral separates or because of analytical problems. New ion probe data for minor and trace elements in anorthite from type B CAIs permit detailed comparisons with fractional crystallization models based on the measured D values. For most comparisons, models and observations do not agree for amounts of crystallization less than 90%. It is possible that anorthite does not appear until after 95% crystallization, compared to about 40% which would be expected from isothermal equilibrium crystallization experiments. The LREEs are highly compatible elements in perovskite, but D values drop sharply for the HREEs, Y, and Zr. D values for REEs increase strongly from air to highly reducing conditions as coupled REE-Ti^(+3) substitutions become possible. Model calculations show that REE patterns in igneous perovskites from CAIs will reflect the D pattern, and the models can explain some REE patterns from compact type A CAIs. However, there are other sets of trace element data for perovskite in CAIs that cannot easily be explained by igneous processes.", "doi": "10.1016/0016-7037(94)90553-3", "issn": "0016-7037", "publisher": "Elsevier", "publication": "Geochimica et Cosmochimica Acta", "publication_date": "1994-03", "series_number": "5", "volume": "58", "issue": "5", "pages": "1507-1523" }, { "id": "authors:4km39-42292", "collection": "authors", "collection_id": "4km39-42292", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170427-090016157", "type": "article", "title": "Murchison xenoliths", "author": [ { "family_name": "Olsen", "given_name": "Edward J.", "clpid": "Olsen-E-J" }, { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Hutcheon", "given_name": "Ian D.", "clpid": "Hutcheon-I-D" }, { "family_name": "Clayton", "given_name": "Robert N.", "clpid": "Clayton-R-N" }, { "family_name": "Mayeda", "given_name": "Toshiko K.", "clpid": "Mayeda-Toshiko-K" }, { "family_name": "Grossman", "given_name": "Lawrence", "clpid": "Grossman-L" } ], "abstract": "C3 xenoliths in a C2 host (Murchison) are unique among known meteoritic xenolith-host occurrences. They offer an opportunity to determine possible effects on the xenoliths by the hydrated host. Eleven xenoliths were found ranging from 2 to 13 mm. Four of these Murchison Xenoliths (MX1, MX2, MX3 and MX4) have been studied in detail. MX1 and MX2 were large enough for trace element, oxygen isotope, carbon isotope, bulk carbon and bulk nitrogen determinations. All four were studied petrographically and by analytical SEM. The xenoliths cannot be unequivocally identified as C3V or C3O subtypes. MX1 contains some matrix phyllosilicate, indicating reaction with water. MX 1, MX2 and MX3 all show extensive alteration by an FeO-rich medium, and some minerals in them contain ferric iron. MX4, however, exhibits very minor alteration by FeO only. Oxygen isotopic and chemical data show that the alteration of these xenoliths did not take place in the Murchison host. The alterations occurred in one or more parent bodies, which were later disrupted to release these xenoliths that ultimately accreted onto the Murchison parent body.", "doi": "10.1016/0016-7037(88)90230-X", "issn": "0016-7037", "publisher": "Elsevier", "publication": "Geochimica et Cosmochimica Acta", "publication_date": "1988-06", "series_number": "6", "volume": "52", "issue": "6", "pages": "1615-1626" }, { "id": "authors:avb4g-xsy58", "collection": "authors", "collection_id": "avb4g-xsy58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150116-132456584", "type": "article", "title": "Chemical composition of HAL, an isotopically-unusual Allende inclusion", "author": [ { "family_name": "Davis", "given_name": "Andrew M.", "clpid": "Davis-A-M" }, { "family_name": "Tanaka", "given_name": "Tsuyoshi", "clpid": "Tanaka-Tsuyoshi" }, { "family_name": "Grossman", "given_name": "Lawrence", "clpid": "Grossman-L" }, { "family_name": "Lee", "given_name": "Typhoon", "clpid": "Lee-T" }, { "family_name": "Wasserburg", "given_name": "G. J.", "orcid": "0000-0002-7957-8029", "clpid": "Wasserburg-G-J" } ], "abstract": "Thirty-seven major, minor and trace elements were determined by INAA and RNAA in samples of hibonite, black rim and portions of friable rim from an unusual Allende inclusion, HAL. The peculiar isotopic, mineralogical and textural properties of HAL are accompanied by very unusual trace element abundances. The most striking feature of the chemistry is the virtual absence of Ce from an inclusion otherwise highly enriched in REE compared to Cl chondrites. HAL is also depleted in Sr, Ba, U, V, Ru, Os and Ir, relative to other refractory elements. Of the lithophile elements determined which are normally considered to be refractory in a gas of solar composition, Sr, Ba, Ce, U and V are the most volatile in oxidizing gases. The distribution of REE between hibonite and rims seems to have been established when hibonite and other refractory minerals were removed at slightly different temperatures from a hot, oxidizing gas in which they previously coexisted as separate grains. On the basis of HAL's chemical and isotopic composition, possible locations for the chemical and mass dependent isotopic fractionation are in ejecta from the low temperature helium-burning zone of a supernova and in the locally oxidizing environment generated by evaporation of interstellar grains of near-chondritic chemical composition.", "doi": "10.1016/0016-7037(82)90319-2", "issn": "0016-7037", "publisher": "Elsevier", "publication": "Geochimica et Cosmochimica Acta", "publication_date": "1982-09", "series_number": "9", "volume": "46", "issue": "9", "pages": "1627-1651" } ]