Petrology and geochemistry of Poikilitic Shergottite NWA 1950: Insights into Martian mantle sources

Martian meteorites offer the only direct samples from Mars available for study, providing critical insights into the planet’s igneous processes and mantle evolution. These meteorites are primarily categorized into three groups—shergottites, chassignites, and nakhlites (SNC), among these, shergottites are the most abundant, comprising approximately 90% of the Martian meteorite collection and exhibiting diverse igneous textures and geochemical signatures [1, 2, 3, 4]. The poikilitic shergottites are distinct from other shergottite subgroups due to their unique bimodal texture, characterized by both poikilitic (PO) and non-poikilitic (NPO) domains, which likely represent two stages of crystallization [5, 6, 7, 8]. These meteorites typically display intermediate to enriched source characteristics, with a depleted counterpart remaining largely unidentified—except for the recent discovery of the 'depleted-like' poikilitic shergottite Asuka 12325 [4, 9, 10]. This study presents new mineralogical and isotopic data for the intermediate poikilitic shergottite Northwest Africa (NWA) 1950 to better constrain its mantle source and parental melt composition. By examining olivine-hosted melt inclusions, we aim to clarify the relationship between intermediate and depleted shergottites and provide new insights into mantle source heterogeneities and enrichment processes on Mars