CHARACTERISING SHOCK DEFORMATION OF THE MARTIAN CRUST BY ELECTRON BACKSCATTER DIFFRACTION ANALYSIS OF THE NAKHLITE METEORITES GOVERNADOR VALADARES AND NWA 998

摘要

The nakhlites are an important subgroup of 20 Martian meteorites that provide crucial informationabout the evolution of Mars including mantle composition, volcanic processes and water-basedalteration [1]. Basaltic in nature the nakhlites are comprised of varying proportions of augite,olivine and mesostasis. Importantly, they generally exhibit lower degrees of impact shockmetamorphism (5 - 27 Gpa, ～5 - 40 K) than other groups of Martian meteorites, including the muchmore abundant shergottites [1, 2]. Thus the nakhlites can provide a clearer view of indigenousMartian processes as they lack the deformation of the more highly shocked specimens.