Abstract
Chemical compositions of about one hundred spherules separated from deep sea sediment dredged off Hawaii island were determined by INAA (Instrumental Neutron Activation Analysis) using KUR (Kyoto University Reactor). Some spherules were identified to be extraterrestrial in origin and are named as cosmic spherules here. In this study, we report the formation mechanism of such cosmic spherule samples in terms of two types of elemental fractionations; fractionations between metal and silicate and between solid metal and liquid metal. From chemical characteristics of the cosmic spherules analyzed, chondrites are assigned as precursor matters for them. Such two fractionations occur when chondrites are heated, melted, and re-solidified into spherules in atmospheric entry.
