吉林陨石冲击波压缩和幔岩模型

应用冲击波试验技术研究吉林陨石在冲击压缩期间所出现的相转变。试验雨贡纽点采用最小二乘方去拟合伯奇-默纳汉或默纳汉状态方程分析。文中提出了估计吉林陨石高压态的零压参数方法;试验结果得出,在高压吉林陨石中大部分矿物形成高压相矿物聚合体。它的零压密度为4.395g/cm3,可能含有零压密度6.32g/cm3的钙钛矿结构矿物。计算得出,吉林陨石硅酸盐相零压密度是4.10g/cm3。显然,它与地球模式的下地幔矿物聚合体的零压密度(4.15g/cm3)极一致。由此得出,原始下地幔可能是普通球粒陨石;原始地核是铁陨石小行星。这样,陨石和铁镁硅酸盐中的铁化物岐变,随着地球增长源源不断的提供外核的铁来源。 

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.