Shock metamorphism of ordinary chondrites

Effects of Metamorphism on the Valence and Coordination of Titanium in Ordinary Chondrites

Petrology of Amoeboid Olivine Aggregates in Antarctic CR chondrites: Evidence for Aqueous Alteration and Shock Metamorphism

Alteration and Shock Metamorphism. M. Komatsu, T. J. Fagan, A. Yamaguchi, T. Mikouchi, M. Yasutake, and M. E. Zolensky SOKENDAI, The Graduate University for Advanced Studies, Kanagawa, Japan ([email protected]), Dept. Earth Sciences, Waseda University, Japan, National Institute of Polar Research (NIPR), Japan, Dept. Earth and Planetary Science, The University of Tokyo, Japan, ARES, NA...

KINETICS AND VOLATILIZATION OF SiC AND S i O 2: IMPLICATIONS FOR METAMORPHISM OF UNEQUILIBRATED ORDINARY CHONDRITES;

Introduction: Constraints on thermal histories and physical conditions during the formation of unequilibrated ordinary chondrites (UOCs; petrologic type 3) are largely based on inferences from more equilibrated varieties (types 4-7). In this study, we explore the possibility of a more direct indicator based on the observation [1, 2] that abundances of diamond and SiC decrease systematically in ...

Ar-Ar DATING OF SHOCK-MELTED ORDINARY CHONDRITES: CHRONOLOGY OF ASTEROIDAL

Ar-Ar dating of 13 samples from 5 shock-melted ordinary chondrites is used to determine the timing of impacts in the Main Asteroid Belt. Three samples of the H impact melt LAP 02240 have welldefined plateaus at ~3900 Ma, consistent with the “lunar cataclysm” and many other meteorite impact ages. The LL impact melt breccia NWA 1701 records an impact at ~1000 Ma, in which melt was more thoroughly...

Petrographic, chemical and spectroscopic evidence for thermal metamorphism in carbonaceous chondrites I: CI and CM chondrites

We present a comprehensive description of petrologic, chemical and spectroscopic features of thermally metamorphosed CI-like and CM (and CM-like) chondrites. Only two such CI chondrites have so far been discovered i.e. Y-86029 and Y82162. Thermal metamorphism in these chondrites is apparent in their low contents of H2O, C and the most thermally labile trace elements, partial dehydration of matr...