吉林陨石(H5)的冲击压缩线及其意义

SHOCK COMPRESSION CURVE OF JILIN CHONDRITE AND ITS SIGNIFICANCES

在二级轻气炮动高压装置上运用电探针技术测量了具有H群球粒陨石典型代表性的吉林陨石冲击压缩线。当冲击压力>～70GPa时,吉林陨石发生相变,其高压相零压密度为4.425g/cm^3,硅酸盐部分高压相零压密度为4.068g/cm^3。吉林陨石冲击压缩性质的研究结果与地球形成的星子堆积模型(IAB铁陨石+H群球粒陨石)一致。此外,根据陨石或其类似物的冲击压缩线,用阻抗匹配原理计算了主要类型陨石中重要冲击特征形成的最小碰撞速度,揭示了陨石冲击效应形成的动力学条件与空间环境。

Shock compression curve of Jilin chcmdrite with H-chondrite representives is measured by the electrical pin technique on the dynamic high pressure device equipped with a two-stage light gas gun. The curve shows that under>70GPa shock pressure Jilin chondrite transforms into the high pressure phase which zero-pressure density is 4.425 g/cm3, and the zero-pressure density of silicates is 4.068 g/cm3. This study results of shock compression pro-perities of H-cho'ndrites are consistent with the planetesimal accumulation model of the Earth formation (1AB iron meteorite + Hgroup chondrite). In addition, minimum impact velocities for important shock features in main types of meteorites are calculated by the impedance-matching principle in term of shock compression curves of meteorites or analogue materials, and then the dynamic condition on formations of shock features in meteorites and the impact environment of their parent bodies are discussed.