滇黔桂裂谷

THE YUNNAN-GUIZHOU-GUANGXI RIFT SYSTEM

滇黔桂裂谷位于扬子板块的西边缘。裂谷作用自泥盆纪开始,到三叠纪结束。裂谷沉积-火山岩系厚逾万米,其中产出有双模式火山岩,有裂谷型建造序列,有以碳酸盐沉积为特征的台地沉积及以泥质与硅质沉积为特征的槽盆沉积的分异。裂谷演化早期与中期碎屑沉积物来源于东西两侧的谷肩地区并在裂谷轴部汇聚后向南搬运;裂谷演化晚期碎屑沉积物来源于南部及东南部并向北及并西向搬运。该裂谷应该是一个向南开口的裂陷槽。

The Yunnan-Guizhou-Guangxi Rift System is located on the western margin of the Yangtze Plate and its rifting activities initiated at the time of Devonian and ended at the Triassic Period. In the rift system,the sedimentary volcanic rocks over 10000 m have been developed with bimodal rift volcanic rocks,sedimentary sequences of rift type,carbonate sedimentary rocks characterized by platform sedimentation,and pelitic and siliceous sediments characterized by sedimentary differentiation of trough-basin. During the early and middle stages of the rift evolution,the clastic sediments were derived from the east and west sides of the rift shoulders and were migrated southward after they accumulated at the rift axis while the clastic sediments were sourced from its southern and southeastern areas and migrated towards north and northwest during the late stage of the rift evolution. Therefore, this rift opens towards south and can be named as a rifted-trough.