KAIDUN METEORITE: CRYSTALS OF OXIDES IN CAVITIES

Abstract

Cavities in two texturally and genetically distinct clasts of the Kaidun meteorite were found out to contain crystals of distinct morphology, but of a similar composition. Cavities in chondrite breccia contain thin (<4 ) elongated (up to 25 long) crystals that grew perpendicular the walls of cavity. cavities in partly fused clast #d(3-5)d are covered with clusters acicular crystals. both clasts, by films phyllosilicates and always have a composition approximated formula (mg,fe,mn)5Al2O8.n H2 O. No mineral phase of this composition has ever been found in nature. The genesis of the mineral phases in the cavities is thought to be related to the crystallization from a fluid of similar composition. The fluid was produced during the cooling of the melt that produced clast #d(3-5)D. The unusual composition of the crystals testifies that this fluid had an unusual composition. This can be explained by the unique nature of clast #d(3-5)D, for which there are good reasons to propose a Martian origin. © Pleiades Publishing, Inc. 2006.