An Almahata Sitta EL3 fragment: implications for the complex thermal history of enstatite chondrites

Abstract Almahata Sitta is a polymict breccia, consisting of many kinds clasts. Here we present our mineralogical and petrological results on an EL3 fragment, MS-177 from Sitta. This fragment shows typical type 3 chondritic texture, well-defined chondrules, isolated silicate minerals, opaque nodules. Most chondrules are enstatite-rich with some having olivine. Although these components chondrites, the mineral abundances compositions different other EL3s. Diopside unusually abundant in MS-177. On hand, perryite daubreelite were not found. The major pyroxene orthoenstatite, silica phase quartz. Fe–Ni metal has relatively high P contents. Troilite enriched Cr Mn. Keilite buseckite From mineralogy experienced high-temperature event under subsolidus conditions. Shock-induced heating for short duration might explain this event. We suggest that E3 chondrites also events such conditions their parent bodies. abundance diopside cannot be explained by secondary thermal may have been primary feature MS-177, formed before accretion to body.