Shock Compression of Jilin Meteorite and Pyrolite Model

Shock-wave instrumentation provides an approach for the study of phase transformation during shock compression of the Jilin meteorite. Experimental Hugoniot points for the Jilin meteorite are analyzed by a least-squares method to fit the Birech-Murnaghan or Murnaghan equation-of-state. In this paper, a method is proposed for estimating the zero-pressure parameter. Experimental result show that high-pressure phase mineral assemblages are present. The zero-pressure density is 4.395 g/cm³. It is concluded that there is a perovskite-strueture mineral with a zero-pressure density of 6.30 g/cm³. The calculation shows that the zero-pressure density of silicate in the Jilin meteorite is 4.10 g/cm³. It appears that dense silicate in the meteorite have a sufficiently high density compatible with that of lower mantle mineral assemblages at zero-pressure. The proto-lower mantle seems to be similar in composition to ordinary chon-drites, while the proto-earth's core is similar in composition to iron meteorites. So the disproportionation of iron and ferromagnesian silicates in chondrites may explain the origin of iron in the process of earth's evolution.