Shock melting origin of a troilite-rich clast in the Moorabiechondrite (L3)

Fujita Takashi, Kitamura Masao
A troilite-rich clast enclosing chondrules was found in the Moorabie chondrite (L3). This chondrite is characterized by elongate mor phology of chondrules produced by shock deformation. Average composition of the metal and troilite grains in the clast is close to the eutectic composition of the Fe-S system, indicating the melting origin of the clast. The eutectic composition provides the heating temperature to be around l000 °C. Size and distribution of troilite and metal grains in the clast
more » ... gest the slow cooling after the melting. Pentlandite as an exsolved phase of troilite in the clast, found first in ordinary chondrites, also supports the melting and slow cooling. Thermal history of the clast indicates that the melting of the opaque minerals and the elongate morphology of chondrules were caused inside the parent body by the shock event which occurred at an early hot stage (around 400 °C) of the cooling after the accretion of the chondrite.
doi:10.15094/00004582 fatcat:jlnvnegiwng6lpif75qcgpc72e