Meteorite from Mars

Dho 019

 

A brownish gray stone weighting 1056 g was found in Dhofar region, Oman.

Mineralogy and classification (M. Nazarov and M. Ivanova of Vernadsky Institute, and L.A. Taylor of University of Tennessee): fusion crust absent; meteorite is a doleritic rock consisting of subhedral grains (0.2-0.5 mm) of pigeonite (Wo 9-15 En 40-70, Fe/Mn=20-40 at.), augite (Wo 30-40 En 40-55), olivine (Fo 25-60, Fe/Mn=50-60 at.), and feldspar (An36-68) converted to maskelynite; olivine has higher Fe/Mn than of coexisting pyroxenes, as it is in nakhlites; mineralogical modes are approx. 65% pyroxene, 25% maskelynite, and 10 % olivine; accessories are silica, K-rich feldspars, whitlockite, chlorapatite, chromite, ilmenite, titanomagnetite, magnetite, and pyrrhotite; secondary phases are calcite, gypsum, smectite, celestite, and Fe hydroxides; shock features include fracturing and mosaicism, maskelynite, and rare impact melt pockets; extensive terrestrial weathering present mainly as carbonate veins crosscutting the meteorite; however there are smectite-calcite-gypsum "orangettes" replacing maskelynite, which are similar to those in ALH84001 and could be of martian origin; in bulk chemistry the meteorite is close to Shergotty; light rare earth elements (LILE) are strongly depleted. Specimens: type specimens of 113 g, 4 g, and 2 g, and two thin sections, Vernadsky Institute; main mass with anonymous finder.

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