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Title: The Miller Range 090340 and 090206 meteorites: Identification of new brachinite-like achondrites with implications for the diversity and petrogenesis of the brachinite clan

Journal Article · · Meteoritics and Planetary Science
DOI:https://doi.org/10.1111/maps.12846· OSTI ID:1368246
 [1];  [2];  [3];  [3];  [4]
  1. Lunar and Planetary Inst., Houston, TX (United States); Planetary Science Inst., Tucson, AZ (United States)
  2. Univ. of Wisconsin, Madison, WI (United States)
  3. Univ. of Chicago, IL (United States)
  4. Rutgers Univ., Piscataway, NJ (United States); American Museum of Natural History (AMNH), New York, NY (United States)

Miller Range (MIL) 090340 and MIL 090206 are olivine-rich achondrites originally classified as ureilites. We investigate their petrography, mineral compositions, olivine Cr valences, equilibration temperatures, and (for MIL 090340) oxygen isotope compositions, and compare them with ureilites and other olivine-rich achondrites. We conclude that they are brachinite-like achondrites that provide new insights into the petrogenesis of brachinite clan meteorites. MIL 090340,6 has a granoblastic texture and consists of ~97 modal % by area olivine (Fo = molar Mg/[Mg+Fe] = 71.3 ± 0.6). It also contains minor to trace augite, chromite, chlorapatite, orthopyroxene, metal, troilite, and terrestrial Fe-oxides. Approximately 80% by area of MIL 090206,5 has a granoblastic texture of olivine (Fo 72.3 ± 0.1) plus minor augite and chromite, similar to MIL 090340 but also containing minor plagioclase. The rest of the section consists of a single crystal of orthopyroxene (~11 × 3 mm), poikilitically enclosing rounded grains of olivine (Fo = 76.1 ± 0.6), augite, chromite, metal, and sulfide. Equilibration temperatures for MIL 090340 and MIL 090206, calculated from olivine-spinel, olivine-augite, and two-pyroxene thermometry range from ~800 to 930 °C. In both samples, symplectic intergrowths of Ca-poor orthopyroxene + opaque phases (Fe-oxides, sulfide, metal) occur as rims on and veins/patches within olivine. Before terrestrial weathering, the opaques were probably mostly sulfide, with minor metal. All petrologic properties of MIL 090340 and MIL 090206 are consistent with those of brachinite clan meteorites, and largely distinct from those of ureilites. Oxygen isotope compositions of olivine in MIL 090340 (δ18O = 5.08 ± 0.30‰, δ17O = 2.44 ± 0.21‰, and Δ17O = -0.20 ± 0.12‰) are also within the range of brachinite clan meteorites, and well distinguished from ureilites. Olivine Cr valences in MIL 090340 and the granoblastic area of MIL 090206 are 2.57 ± 0.06 and 2.59 ± 0.07, respectively, similar to those of three brachinites also analyzed here (Brachina, Hughes 026, Nova 003). They are higher than those of olivine in ureilites, even those containing chromite. The valence systematics of MIL 090340, MIL 090206, and the three analyzed brachinites (lower Fo = more oxidized Cr) are consistent with previous evidence that brachinite-like parent bodies were inherently more oxidized than the ureilite parent body. The symplectic orthopyroxene + sulfide/metal assemblages in MIL 090340, MIL 090206, and many brachinite clan meteorites have superficial similarities to characteristic “reduction rims” in ureilites. However, they differ significantly in detail. They likely formed by reaction of olivine with S-rich fluids, with only minor reduction. MIL 090340 and the granoblastic area of MIL 090206 are similar in modal mineralogy and texture to most brachinites, but have higher Fo values typical of brachinite-like achondrites. The poikilitic pyroxene area of MIL 090206 is more typical of brachinite-like achondrites. The majority of their properties suggest that MIL 090340 and MIL 090206 are residues of low-degree partial melting. The poikilitic area of MIL 090206 could be a result of limited melt migration, with trapping and recrystallization of a small volume of melt in the residual matrix. Finally, these two samples are so similar in mineral compositions, Cr valence, and cosmic ray exposure ages that they could be derived from the same lithologic unit on a common parent body.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
Grant/Contract Number:
FG02-94ER14466; NNX12AH74G; EAR-1128799
OSTI ID:
1368246
Journal Information:
Meteoritics and Planetary Science, Vol. 52, Issue 5; ISSN 1086-9379
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
ENGLISH
Citation Metrics:
Cited by: 19 works
Citation information provided by
Web of Science

References (58)

The Divnoe meteorite: Petrology, chemistry, oxygen isotopes and origin journal March 1994
ATHENA , ARTEMIS , HEPHAESTUS : data analysis for X-ray absorption spectroscopy using IFEFFIT journal June 2005
Fe/Mg–Fe/Mn relations of meteorites and primary heterogeneity of primitive achondrite parent bodies journal January 2000
Ureilitic breccias: clues to the petrologic structure and impact disruption of the ureilite parent asteroid journal November 2004
High precision SIMS oxygen isotope analysis and the effect of sample topography journal June 2009
Origin of felsic achondrites Graves Nunataks 06128 and 06129, and ultramafic brachinites and brachinite-like achondrites by partial melting of volatile-rich primitive parent bodies journal March 2012
Oxygen isotope variation in primitive achondrites: The influence of primordial, asteroidal and terrestrial processes journal October 2012
Brachina: A new type of meteorite, not a chassignite journal January 1983
Calcium exchange between olivine and clinopyroxene calibrated as a geothermobarometer for natural peridotites from 2 to 60 kb with applications journal September 1990
Metallic phases and siderophile elements in main group ureilites: Implications for ureilite petrogenesis journal July 2013
Brachinite meteorites: Partial melt residues from an FeO-rich asteroid journal October 2014
Differentiation processes in FeO-rich asteroids revealed by the achondrite Lewis Cliff 88763 journal September 2015
Geochemical studies of feldspathic fragmental breccias and the nature of North Ray Crater ejecta journal January 1983
Mineralogy of coexisting pyroxenes in magnesian ureilites and their formation conditions journal June 1989
Oxygen isotope studies of achondrites journal June 1996
The Tafassasset primitive achondrite: Insights into initial stages of planetary differentiation journal May 2012
Thermodynamic constraints on the formation conditions of winonaites and silicate-bearing IAB irons journal November 2005
A XANES determination of the oxidation state of chromium in silicate glasses journal May 2004
Widespread magma oceans on asteroidal bodies in the early Solar System journal June 2005
Cr spinel and chromite as petrogenetic indicators in ordinary chondrites: Equilibration temperatures of petrologic types 3.7 to 6 journal November 2005
Brachinites: Igneous rocks from a differentiated asteroid journal November 2003
Petrology of unique achondrite Queen Alexandra Range 93148: A piece of the pallasite (howardite-eucrite-diogenite?) parent body? journal May 2000
Oxygen isotope studies of carbonaceous chondrites journal July 1999
A two-pyroxene thermometer journal January 1983
Chromium valences in ureilite olivine and implications for ureilite petrogenesis journal December 2013
Northwest Africa 1500: Plagioclase-bearing monomict ureilite or ungrouped achondrite? journal June 2006
Fragments of ancient lunar crust: Petrology and geochemistry of ferroan noritic anorthosites from the Descartes region of the Moon journal February 1995
A menagerie of graphite morphologies in the Acapulco meteorite with diverse carbon and nitrogen isotopic signatures: Implications for the evolution history of acapulcoite meteorites journal September 2005
Origin and evolution of the ureilite parent magmas: Multi-stage igneous activity on a large parent body journal September 1987
Origin of sulfide replacement textures in lunar breccias. Implications for vapor element transport in the lunar crust journal April 2012
Redox variations in the inner solar system with new constraints from vanadium XANES in spinels journal September 2016
Petrogenesis of augite-bearing ureilites Hughes 009 and FRO 90054/93008 inferred from melt inclusions in olivine, augite and orthopyroxene journal May 2009
Oxygen isotope studies of ordinary chondrites journal August 1991
Mineralogy of new Antarctic achondrites with affinity to Lodran and a model of their evolution in an asteroid journal November 1994
High precision SIMS oxygen three isotope study of chondrules in LL3 chondrites: Role of ambient gas during chondrule formation journal November 2010
Frontier Mountain 93001: A coarse-grained, enstatite-augite-oligoclase-rich, igneous rock from the acapulcoite-lodranite parent asteroid journal August 2006
Record of S-rich vapors on asteroid 4 Vesta: Sulfurization in the Northwest Africa 2339 eucrite journal May 2013
Petrology of chromite in ureilites: Deconvolution of primary oxidation states and secondary reduction processes journal June 2014
TEM investigations on the monomict ureilites Jalanash and Hammadah al Hamra 064 journal January 2003
Primary trapped melt inclusions in olivine in the olivine-augite-orthopyroxene ureilite Hughes 009 journal February 2001
QUILF: A pascal program to assess equilibria among FeMgMnTi oxides, pyroxenes, olivine, and quartz journal October 1993
Primary igneous carbon in ureilites: Petrological implications journal January 1982
A comparison of FeO-rich, porphyritic olivine chondrules in unequilibrated chondrites and experimental analogues journal June 1993
The Northwest Africa 1500 meteorite: Not a ureilite, maybe a brachinite: NWA 1500: A brachinite? journal December 2010
Parent body depth-pressure-temperature relationships and the style of the ureilite anatexis: Ureilite anatexis journal January 2012
The Rumuruti chondrite group journal May 2011
The systematics of Cr (super 3+) and Cr (super 2+) partitioning between olivine and liquid in the presence of spinel journal August 1998
Ordinary (mesostasis) and not-so-ordinary (symplectites) late-stage assemblages in howardites: Symplectites in howardites journal September 2012
Redox processes in glass-forming melts journal July 1986
Mineralogy of augite-bearing ureilites and the origin of their chemical trends journal June 1989
Isotopic fractionation and the quantification of 17 O anomalies in the oxygen three-isotope system journal June 2002
Frontier Mountain meteorite specimens of the acapulcoite-lodranite clan: Petrography, pairing, and parent-rock lithology of an unusual intrusive rock journal April 2008
HaverÖ Ureilite: Evidence for Recrystallization and Partial Reduction journal December 1972
A general equation for estimating Fe 3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria journal September 1987
Microfluorescence and Microtomography Analyses of Heterogeneous Earth and Environmental Materials journal January 2002
Acapulco- and Lodran-like achondrites: Petrology, geochemistry, chronology, and origin journal March 1996
A petrologic, thermodynamic and experimental study of brachinites: Partial melt residues of an R chondrite-like precursor journal December 2013
Index to CMN, Vol. 34, 2012 journal December 2012

Cited By (3)

The first samples from Almahata Sitta showing contacts between ureilitic and chondritic lithologies: Implications for the structure and composition of asteroid 2008 TC 3 journal August 2019
Possible records of space weathering on Vesta: Case study in a brecciated eucrite Northwest Africa 1109 journal January 2019
Petrological, petrofabric, and oxygen isotopic study of five ungrouped meteorites related to brachinites journal January 2019

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