The origin of the unique achondrite Northwest Africa 6704: Constraints from petrology, chemistry and Re-Os, O and Ti isotope systematics.

ABSTRACT: Northwest Africa (NWA) 6704 is a unique achondrite characterized by a near-chondritic major element composition with a remarkably intact igneous texture. To investigate the origin of this unique achondrite, we have conducted a combined petrologic, chemical, and ¹⁸⁷Re-¹⁸⁷Os, O, and Ti isotopic study. The meteorite consists of orthopyroxene megacrysts (En_55-57Wo_3-4Fs_40-42; Fe/Mn = 1.4) up to 1.7 cm in length with finer interstices of olivine (Fa_50-53; Fe/Mn = 1.1-2.1), chromite (Cr# ~ 0.94), awaruite, sulfides, plagioclase (Ab₉₂An₅Or₃) and merrillite. The results of morphology, lattice orientation analysis, and mineral chemistry indicate that orthopyroxene megacrysts were originally hollow dend

SUBMITTER: Hibiya Y 

PROVIDER: S-EPMC6457475 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature