Sayh al Uhaymir 094: A new martian meteorite from the Oman desert

Abstract

Abstract— Sayhal Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine‐porphyric rock of the shergottite group showing a microgabbroic texture. The rock consists of pyroxene (52.0–58.2 vol%)—dominantly prismatic pigeonite (En 60–68 Fs 20–27 Wo 7–9 ) associated with minor augite (En 46–49 Fs 15–16 Wo 28–31 )—brown (shock‐oxidized) olivine (Fo 65–69 ; 22.1–31%), completely isotropic interstitial plagioclase glass (maskelynite; An 50–64 Or 0.3‐0.9 ; 8.6–13.0%), chromite and titanian magnesian chromite (0.9‐1.0%), traces of ilmenite (Ilm 80–86 ), pyrrhotite (Fe 92–100 ; 0.1‐0.2%), merrillite (<<0.1%), and pockets (4.8‐6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (1.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1‐0.6% of the rock. X‐ray tomography revealed that the specimen contains ˜0.4 vol% of shock‐melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calcite‐veining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance of chromite among the oxides, and abundance of olivine indicate affinities to the lherzolitic shergottites.