西昌地区岩浆活动特征及其与构造地质的关系

本文泛指的西昌地区包括北起冕宁-越西;南至会理-会东;东起昭觉-巧家;西达盐边-盐源的区域。该区域位于华南台块的最西缘,包括康滇台背斜的中北部、滇桂台向斜的西部边缘及盐源台缘拗陷。近年来,许多研究工作表明,一定类型的岩浆岩组合发育于一定类型的地壳结构的地区中,并与地质构造发育的阶段和构造的性质相联系。这种规律已普遍地被人们承认。西昌地区,尤其是安宁河谷两侧,广泛出露不同时代、不同产状、不同成分的岩浆岩,组成了岩浆杂岩带。

CHARACTERISTICS OF MAGMATIC ACTIVITY IN THE SICHANG AREA AND ITS BEARING ON THE TECTONIC GEOLOGICAL DEVELOPMENT

Basing on the paleogeographical developments and strongly polycyclic magmatic activities, as well as on the chemical compositions of magma, the characteristics of tectonic evolution in the Sichang area are discussed in this paper. All the magmatic activities exactly controlled by the nearly north-south trending deep fracture zone. As a result of progressive structural developments of this zone, was formed a Cenozoic graben-like basin belt which is very similar in tectonic and geological characteristics as the Eift Valley of Africa.