41st Lunar and Planetary Science Conference (2010) sess608.pdf
Thursday, March 4, 2010 POSTER SESSION II: THERMAL AND AQUEOUS PROCESSES ON CHONDRITE PARENT BODIES 7:00 p.m. Town Center Exhibit Area
Harrison K. P. Grimm R. E. Thermal History of the H-Chondrite Parent Body Reconsidered [#1794] We present a broad survey of available H-chondrite age and cooling rate data which, together with thermal and dynamical simulations, constrain the early history of the parent body.
Komatsu M. Fagan T. Watanuki H. Norose K. Matsui K. Wakai H. Variable Equilibration in Silicates and Sulfides in Enstatite Chondrites: Implications for Metamorphic and Nebular Reaction Histories [#1522] Textures, EPMA and EBSD results from a set of enstatite chondrites indicate that pyroxenes from metamorphosed ECs preserve near-peak compositions, whereas troilite compositions continued to change during post-metamorphic- peak cooling.
Jones R. H. Dreeland L. Phosphate Minerals in the LL6 Chondrite, St. Séverin [#1972] Merrillite and chlorapatite in St. Séverin both show compositional heterogeneity, including variable FeO contents and F/Cl ratios. At least some phosphate grain growth appears to postdate peak metamorphism, possibly in the presence of fluids.
Le Gac Y. Benedix G. K. Bland P. A. Lyon I. Henkel T. Rost D. Russell S. S. A 750µm-Wide Sub-Hexagonal Clast in the Matrix of Orgueil [#1940] We report an unusual regular-sided clast in the matrix of Orgueil (CI1), around 0.75 mm in diameter. We use SEM, EMPA and ToF-SIMS techniques to study this clast, and discuss its potential origins.
Blinova A. Herd C. D. K. Insights into the Mineralogy of the Tagish Lake Meteorite Through EPMA, XRD and CL [#2140] We present new EPMA, XRD and CL data on the new lithologies from the Tagish Lake C2 carboneceous chondrite.
Petitat M. Gounelle M. Magnetite Content and Carbonate Mineralogy as Constraints for Parent Body Hydrothermal Alteration [#1673] We present a mineralogical study of magnetite and carbonates from various C1s and C2s in order to improve our understanding of the relationships between these two minerals and between these meteorite groups.
Mironenko M. V. Zolotov M. Yu. Marshakov A. I. Yurasova T. A. Rybkina A. A. Dissolution Rate of Kamacite: Electrochemical Study Under Anoxic Aqueous Conditions [#1403] We report dissolution rate of kamacite from the Sikhote-Alin iron meteorite in neutral anoxic water at 25°C and discuss implications for aqueous processes in parent bodies of carbonaceous chondrites.
Palmer E. E. Lauretta D. S. A Kamacite Alteration Index for CM Chondrites [#2211] We establish an alteration scale for aqueous alteration of kamacite on CM chondrites. Kamacite alters into tochilinite and P-rich sulfides. We use the width of the tochilinite rim to establish the degree of alteration.
Howard K. T. Benedix G. K. Bland P. A. Greenwood R. C. Franchi I. A. Cressey G. Correlated Modal Mineralogy, Aqueous Alteration and Oxygen Isotope Composition of CM Chondrites [#1595] In this study we move beyond defining alteration sequences in CM chondrites towards understanding the relationship between modal mineralogy, the extent of aqueous alteration and O-isotope compositions. 41st Lunar and Planetary Science Conference (2010) sess608.pdf
Sugiura N. Ichimura K. Fujiya W. Takahata N. A Progress Report on the Mn/Cr Relative Sensitivity for Carbonate Measured with a NanoSIMS [#1617] Mn/Cr relative sensitivity for a synthetic calcite was measured by SIMS. The relative Mn/Cr sensitivity is time-dependent. The time-averaged RSF for the calcite spot analysis is significantly lower than that for San Carlos olivine.
Tyra M. A. Brearley A. J. Matzel J. Hutcheon I. D. Types and Timescales of Secondary Carbonate in CR1 Chondrite GRO 95577 [#2614] GRO 95577 is the only CR chondrite classified as type 1. We show that it possesses multiple carbonate phases (calcite, dolomite, and high Fe, Mn, and Mg “siderite”). We analyzed the short-lived Mn/Cr system (NanoSIMS) within the “siderite” and present preliminary results.
Pravdivtseva O. Meshik A. Hohenberg C. M. Possible Late and/or Prolonged Aqueous Alteration in CR Chondrites Parent Body [#2285] The I-Xe system in two studied Acfer 059 chondrules indicates that it may have been reset by aqueous alteration about 55 Ma after formation of CAIs.
Varela M. E. Kurat G. Zinner E. Hoppe P. Dark Inclusion Allende 4884-2B Provides New Insights on the Formation of Fayalitic Olivine [#1317] We combine a chemical and petrographic study of the Allende DI 4884-2B and a ATEM study of Allende DI All-AF (NHM, Vienna) in order to get new insights onto the genesis of these objects.
Ford R. L. Brearley A. J. Discovery of Vesuvianite and Kaolinite Formed During the Alteration of Melilite in an Allende Type A CAI: Characterization by FIB/TEM [#1402] While examining alteration in Allende CAIs, we observed margarite, grossular, vesuvianite and kaolinite. This is the first reporting of kaolinite and vesuvianite in an Allende CAI, further constraining alteration conditions for Allende CAIs.