云南地壳和上地幔的岩石学结构

PETROLOGICAL STRUCTURE OF THE CRUST AND UPPER MATLE IN YUNNAN, CHINA

通过对地表出露变质岩、深部地震测深资料和高温高压岩石波速测试资料的综合分析 ,研究了云南地壳和上地幔岩石组成。结果表明 ,云南上、中、下地壳分别由绿片岩相 (顶部为沉积层 )、角闪岩相和麻粒岩相变质岩组成或分别由与之相当的花岗岩类、闪长岩类、辉长岩类组成 ,部分地区地壳底部有镁铁质榴辉岩存在。上地幔由橄榄岩组成 ,部分地区 (兰坪思茅坳陷和滇中坳陷 )壳幔过渡带可能由镁铁质榴辉岩和橄榄岩组成。

Through the comprehensive studies of the metamorphic rocks outcropping on the surface, DSS data, and experimental data of rock seismic velocity under high temperature and high pressure, the rock constituents of the crust and upper mantle for Yunnan Province have been studied. This research indicates that the upper, middle and lower crust in Yunnan is composed of the metamorphic rocks of greenschist (sedimentary layer in the top part), amphibolite and granulite facies, respectively or granitoids, diorites and gabbros corresponding to them respectively, and that there exist the mafic eclogites in the bottom of the crust in some areas; and that the upper mantle is composed of peridotites and the crust upper mantle transitional zone probably composed of the mafic eclogites and peridotites in some areas such as Lanping Simao depression and Central Yunnan depression.