Fe‐Mn systematics of type IIA chondrules in unequilibrated CO, CR, and ordinary chondrites

Abstract– We have examined Fe/Mn systematics of 34 type IIA chondrules in eight highly unequilibrated CO, CR, and ordinary chondrites using new data from this study and prior studies from our laboratory. Olivine grains from type IIA chondrules in CO chondrites and unequilibrated ordinary chondrites (UOC) have significantly different Fe/Mn ratios, with mean molar Fe/Mn = 99 and 44, respectively. Olivine analyses from both these chondrite groups show well‐defined trends in Mn versus Fe (afu) and molar Fe/Mn versus Fe/Mg diagrams. In general, type IIA chondrules in CR chondrites have properties intermediate between those in UOC and CO chondrites. In most UOC and CR type IIA chondrules, the Fe/Mn ratio of olivine decreases during crystallization, whereas in CO chondrites the Fe/Mn ratio does not appear to change. It is difficult to interpret the observed Fe/Mn trends in terms of differing moderately volatile element depletions inherited from precursor materials. Instead, we suggest that significant differences in the abundances of silicates and sulfides ± metals in the precursor material, as well as open‐system behavior during chondrule formation, were responsible for establishing the different Fe/Mn trends. Using Fe‐Mn‐Mg systematics, we are able to identify relict grains in type IIA chondrules, which could be derived from previous generations of chondrules, including chondrules from other chondrite groups, and possibly chondritic reservoirs that have not been sampled previously.

[1]  A. Brearley,et al.  Early solar system processes recorded in the matrices of two highly pristine CR3 carbonaceous chondrites, MET 00426 and QUE 99177 , 2010 .

[2]  C. Floss,et al.  Auger Nanoprobe analysis of presolar ferromagnesian silicate grains from primitive CR chondrites QUE 99177 and MET 00426 , 2009 .

[3]  A. Tsuchiyama,et al.  Chondrulelike Objects in Short-Period Comet 81P/Wild 2 , 2008, Science.

[4]  M. Spilde,et al.  Determining Bulk Chemical Compositions of Chondrules by Electron Microprobe: Modal Recombination versus Defocused Beam Analyses , 2008, Microscopy and Microanalysis.

[5]  F. Ciesla,et al.  The Formation Conditions of Chondrules and Chondrites , 2008, Science.

[6]  N. Kita,et al.  Condensation of major elements during chondrule formation and its implication to the origin of chondrules , 2008 .

[7]  H. Palme,et al.  The conditions of chondrule formation, Part I: Closed system , 2007 .

[8]  L. Bonal,et al.  Organic matter and metamorphic history of CO chondrites , 2007 .

[9]  K. Righter,et al.  The Meteoritical Bulletin, No. 91, 2007 March , 2007 .

[10]  G. Libourel,et al.  Role of gas-melt interaction during chondrule formation , 2006 .

[11]  R. Jones,et al.  Identification of relict forsterite grains in forsterite-rich chondrules from the Mokoia CV3 carbonaceous chondrite , 2006 .

[12]  F. Ciesla.  Chondrule-forming Processes--An Overview , 2005 .

[13]  J. Shelley,et al.  Origin of chondritic forsterite grains , 2005 .

[14]  A. Brearley,et al.  The onset of metamorphism in ordinary and carbonaceous chondrites , 2005 .

[15]  Alan E. Rubin,et al.  Chemical, Mineralogical and Isotopic Properties of Chondrules: Clues to Their Origin , 2004 .

[16]  F. Richter,et al.  Evaporation and Condensation During CAI and Chondrule Formation , 2004 .

[17]  K. Keil,et al.  Amoeboid olivine aggregates and related objects in carbonaceous chondrites: records of nebular and asteroid processes , 2004 .

[18]  A. Rubin,et al.  Oxygen-isotopic compositions of relict and host grains in chondrules in the Yamato 81020 CO3.0 chondrite 1 1 Associate editor: A. N. Krot , 2004 .

[19]  H. Palme,et al.  Petrographic and oxygen-isotopic study of refractory forsterites from R-chondrite Dar al Gani 013 (R3.5–6), unequilibrated ordinary and carbonaceous chondrites , 2004 .

[20]  R. Clayton.  Oxygen Isotopes in Meteorites , 2003 .

[21]  K. Lodders.  Solar System Abundances and Condensation Temperatures of the Elements , 2003 .

[22]  A. Rubin,et al.  Ubiquitous Low-FeO Relict Grains in Type II Chondrules and Limited Overgrowths on Phenocrysts Following the Final Melting Event , 2003 .

[23]  C. Shearer,et al.  Olivine from planetary basalts: Chemical signatures that indicate planetary parentage and those that record igneous setting and process , 2003 .

[24]  J. Papike,et al.  Letter. Determination of planetary basalt parentage: A simple technique using the electron microprobe , 2003 .

[25]  A. Rubin,et al.  Mineralogy and petrology of amoeboid olivine inclusions in CO3 chondrites: Relationship to parent‐body aqueous alteration , 2002 .

[26]  D. Sears,et al.  Thermoluminescence sensitivity and thermal history of type 3 ordinary chondrites: Eleven new type 3.0–3.1 chondrites and possible explanations for differences among H, L, and LL chondrites , 2002 .

[27]  J. Zipfel,et al.  The Meteoritical Bulletin, No. 86, 2002 July , 2002 .

[28]  A. Brearley,et al.  Zoned chondrules in Semarkona: Evidence for high‐ and low‐temperature processing , 2002 .

[29]  Monica M. Grady,et al.  Catalogue of Meteorites , 2000 .

[30]  H. Palme,et al.  Refractory forsterite in primitive meteorites: Condensates from the solar nebula? , 2000 .

[31]  J. Grossman.  The Meteoritical Bulletin, No. 83, 1999 July , 1999 .

[32]  L. Danielson,et al.  A chondrule origin for dusty relict olivine in unequilibrated chondrites , 1997 .

[33]  S. Bajt,et al.  In Situ Determination of Chromium Oxidation State in Olivine from Chondrules , 1996 .

[34]  R. Ash,et al.  Carbon and the formation of reduced chondrules , 1994, Nature.

[35]  G. Lofgren,et al.  A comparison of FeO-rich, porphyritic olivine chondrules in unequilibrated chondrites and experimental analogues , 1993 .

[36]  A. Brearley.  Matrix and fine-grained rims in the unequilibrated CO3 chondrite, ALHA77307: Origins and evidence for diverse, primitive nebular dust components , 1993 .

[37]  D. Mckay,et al.  The Mn‐Fe negative correlation in olivines in ALHA 77257 ureilite , 1993 .

[38]  G. Wasserburg,et al.  An experimental study of trace element partitioning between olivine, orthopyroxene and melt in chondrules: equilibrium values and kinetic effects , 1993 .

[39]  D. Sears,et al.  Chemical and physical studies of chondrites: X. Cathodoluminescence and phase composition studies of metamorphism and nebular processes in chondrules of type 3 ordinary chondrites , 1992 .

[40]  D. Rubie,et al.  Thermal histories of CO3 chondrites: Application of olivine diffusion modelling to parent body metamorphism , 1991 .

[41]  R. Clayton,et al.  Oxygen isotope studies of ordinary chondrites , 1991 .

[42]  E. Scott,et al.  DISENTANGLING NEBULAR AND ASTEROIDAL FEATURES OF CO3 CARBONACEOUS CHONDRITE METEORITES , 1990 .

[43]  F. Wlotzka.  The Meteoritical Bulletin , 1990 .

[44]  Rhian H. Jones,et al.  Petrology and mineralogy of Type II, FeO-rich chondrules in Semarkona (LL3.0) - Origin by closed-system fractional crystallization, with evidence for supercooling , 1990 .

[45]  D. Mckay,et al.  Unusual olivine and pyroxene composition in interplanetary dust and unequilibrated ordinary chondrites , 1989, Nature.

[46]  G. Lofgren.  Dynamic cyrstallization of chondrule melts of porphyritic olivine composition: Textures experimental and natural , 1989 .

[47]  G. J. Taylor,et al.  Chondrules and other components in C, O, and E chondrites: Similarities in their properties and origins , 1983 .

[48]  Jeffrey N. Grossman,et al.  Refractory precursor components of Semarkona chondrules and the fractionation of refractory elements among chondrites , 1983 .

[49]  J. Berlin.  Mineralogy and bulk chemistry of chondrules and matrix in petrologic type 3 chondrites : implications for early solar system processes , 2010 .

[50]  H. Yurimoto,et al.  Oxygen Isotopes of Chondritic Components , 2008 .

[51]  D. Lauretta,et al.  Oxygen Isotopes and the Nature and Origins of Type-II Chondrules in CR2 Chondrites , 2008 .

[52]  N. Abreu.  Fine-scale mineralogical study of the matrices of CR carbonaceous chondrites: Insights on early solar system processes , 2007 .

[53]  Adrian J. Brearley,et al.  The Action of Water , 2006 .

[54]  J. Delaney,et al.  Fe/Mg–Fe/Mn relations of meteorites and primary heterogeneity of primitive achondrite parent bodies , 2000 .

[55]  J. Grossman.  The Meteoritical Bulletin, No. 81 , 1997 .

[56]  A. Boss.  A concise guide to chondrule formation models. , 1996 .

[57]  D. Sears,et al.  Open-system behavior during chondrule formation , 1994 .

[58]  R. Jones.  Relict Grains in Chondrules: Evidence for Chondrule Recycling , 1994 .

[59]  R. Jones.  On the relationship between isolated and chondrule olivine grains in the carbonaceous chondrite ALHA77307 , 1992 .

[60]  Bartoschewitz Meteorite.  Catalogue of Meteorites , 1940, Nature.