摘要
扬子地区古生代盆地基底普遍具有双层结构,下层中深变质基底由太古-下元古界麻粒岩相-角闪岩相、角闪岩相-高绿片岩相变质岩组成,同位素地质年龄为25～31亿年、20～25亿年,反映了陆核、陆块两个不同的发展阶段;上层浅变质基底由中元古界低绿片岩相变质岩组成,同位素地质年龄为10～20亿年,中元古代末的内硅铝造山作用及A型俯冲作用使全区连成不成熟的泛大陆,其西部、北部则发展为低稳定性的克拉通。
The basement duplex structures are widely developed in the Paleozoic basins of the Yangtze Area. The intermediate metamorphic and hypometamorphic basements in the lower structural level mainly consist of the metamorphic rocks attributed to the Archaean-Lower Proterozoic granulite-amphibolite facies and amphibolite-greenschist facies with the isotopic ages of 2500-3100 Ma and 2000-2500 Ma respectively, revealing the formation of continental core and blocks in two different stages. The epimetamorphic basements of the upper structural level are Composed of the Middle Proterozoic metamorphic rocks of low -grade greenschist facies with the isotopic ages of 1000-2000Ma. The intra-sialic orogenesis at the end of the Middle Proterozoic and the A-subduction unified the whole area as an immature pan -continent of which the northern and western developed into cratons with low stability.
出处
《石油实验地质》
CAS
CSCD
北大核心
1993年第4期370-384,共15页
Petroleum Geology & Experiment
