论中地壳及其地质意义

地壳深 部结构开始引起重视。中地壳与油气、金属矿床、地震之间的关系特别受到关注。地震低速、高导低阻、低密度是中地壳的主要地球物理特征。研究表明:当中地壳地震波速v,<6.0km/s,密度ρ<2.75g/cm3时,有油气生成及油气藏;而当中地壳地震波速0>6.0km/s,密度ρ>2.75g/cm3时，则有金属Fe、Cu、Ni、Au等成矿。深入研究中地壳的地球物理体的地质属性对油气、金属成矿、地震等的预测有重大意义，特别对大型、超大型油气田、金属矿床的勘探有重要意义。

Discussion on the Mid-Crust and Its Geological Implication

The deep structure of the earth crust is a topic focus. The relation among petroleum, metal deposit, earthquake and mid-crust is con-cerned. Low seismic velocity, high conductivity (low resistance), low density are the important geophysical features of the mid-crust. The investi-gation shows that when the seismic velocity of the mid-crust Pp<6.0 km/s, p<2.75 g/ cm', there exist hydrocarbon generation and oil-gas reser-voirs; when Vvp>6.0 km/s, p>2.75 g/cm', there exist Fe, Cu, Ni, Au and other metal deposits. To study the geological features of the mid-crust isof significance for exploration of oil-gas and metal deposits, particularly, for big and giant oil-gas fields and metal deposits, and for prediction ofthe earthquakes as well.