Abstract
SummarySitathali is an olivine-bronzite chondrite, consisting largely of olivine (Fa18) and orthopyroxene (Fs19) with minor amounts of a clinopyroxene (Ca36Fe12Mg52), plagioclase (An12), nickel-iron, troilite, chromite, and a phosphate (apatite or merrillite). The chemical analysis of a 4 gm sample gave SiO2 39·85, TiO2 0·10, Al2O3 2·84, Cr2O3 0·35, FeO 13·27, MnO 0·28, MgO 23·01, CaO 1·84, Na2O 0·65, K2O 0·15, H2O+ 0·23, H2O− 0·05, P2O5 0·25, FeS 5·09, Fe 10·22, Ni 1·58, Co tr. total 99·76. The metal displays Neumann bands, some deformed, as well as areas of apparent flowage. Troilite locally exhibits twin lamellae and in places replaces kamacite in the plessite fields. Elsewhere it is in braided veinlets and globules, both reflecting former melting. The varied textures suggest a complex post-formational history encompassing several deformational events presumably due to breakups and possible extraterrestrial impacts.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have