摘要
昆阳拗拉谷是中元古代的大陆裂谷作用产物,发育于西南地台西缘康滇地轴以康定杂岩为代表的刚性陆壳之上,以安宁河-绿汁江断裂和小江断裂为边界。其早期破裂阶段以碱性的基性岩浆活动为特征,以大红山群、河口群中的火山岩为代表。在拉张裂陷阶段,昆阳拗拉谷形成狭长的地堑式槽地,沉积了一套典型的裂谷型沉积建造组合,从陆相红色碎屑建造开始,演化为含蒸发岩的白云岩建造、海相黑色页岩及碳酸盐岩建造等,构成了下昆阳群,并赋存了著名的东川式铜矿。
The Kunyang aulacogen is a continental rift which initiated in the beginning of the Middle Proterozoic. It developed on the rigid continental crust represented by the crystalline Kangding complexes in the Xikang-Yunnan axis on the western margin of the Southwest platform, and was bounded by two N-S-trending deep faults—the Anninghe-Luzhijiang fault and the Xiaojiang fault. The early stage of crust rupture was characterized by alkaline mafic igneous activities in the Dahongshan Group and Hekou Group. During the extensional-taphorogenic stage the aulacogen evolved to form a graben where sedimentation of the Kunyang Group took place. The sedimentary sequence comprises terrestrial red beds, algal dolomite, marine black shale and carbonate rocks, which are typical of the rift sedimentary association, and contain well-known Dongchuan type stratabound copper deposits.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1990年第4期289-301,共13页
Acta Geologica Sinica
