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Petrology and Geochemistry of Poikilitic Shergottite Northwest Africa 1950: bridging the gap between depleted and intermediate sources in Martian Mantle.

Nair VM, Sarbadhikari AB, Bhuvan GNSS, Kumar TV, Sorcar N, Mukherjee S, Babu EVSSK, Ray, JS.

GEOCHIMICA ET COSMOCHIMICA ACTA

https://doi.org/10.1016/j.gca.2025.09.043 

A detailed petrographic, in-situ trace element, and whole-rock Sr-Nd isotopic data on the Martian Meteorite Northwest Africa (NWA) 1950. NWA 1950 is a poikilitic shergottite a rarity among the Martian meteorites. The trace element composition of the primary constituent phases such as olivine and the modal proportion of pyroxene and plagioclase resemble the depleted olivine-phyric shergottites. Mixing of a late residual trapped liquid with the parent melt in the Martian upper mantle produced the intermediate range REE abundance and Sr-Nd isotopic composition in NWA 1950. This conclusion supports the hypothesis of chemical layering at the depleted upper mantle of Mars with the residual melt pockets.

Backscattered electron image. PO - Poikilitic and NPO - Non poikilitic domain; Ol-olivine; Pyx-Pyroxene, Mask-Maskelynite, Spn-Spinel (b) Composite X-ray elemental map of NWA 1950. Red-Mg, Green-Ca, Blue-Al and Cyan-Cr.

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