Vestnik Otdelenia nauk o Zemle RAN VOL. 2, NZ6023, doi:10.2205/2010NZ000041, 2010

Elemental composition of the granulometric metal fractions from ADHI KOT EH4 and PILLISTFER EL6 enstatite chondrites: search for evidences of the impact-induced element fractionations

Lyul A. Yu., Z. A. Lavrenteva, G. M. Kolesov

Abstract

In order to search the impact-induced fractionation of siderophile elements in the enstatite chondrites the Ni, Co, Au, As, Ga, Cu and Ir distribution among the grain-size metal fractions of Adhi Kot EH4 and Pillistfer EL6 chondrites having different impact-metamorphic histories is considered. It is supposed that the observed enrichment in refractory Ir and depletion in moderately volatile Ni, Au, As and Ga of the finest (< 45 μm) metal fraction of Adhi Kot impact-melt breccia can be caused by a partial volatilization of more volatile elements during impact heating of chondrite. In highly equilibrated chondrites the impact-induced fractionation of siderophile elements is almost completely erased by during the following metamorphic heating of chondritic material.

Received 28 April 2010; published 5 June 2010.