摘要
位于华南板块南缘的右江盆地的轮廓和内部结构,与NW向及 NE向同沉积断裂关系密切。它的发展可分为两个不同的阶段。海西 构造阶段。由于哀牢山—红河洋盆开裂,右江地区出现若干平行分布的 NW向裂陷带,沉积物以深水相为主,盆地具有大陆被动边缘裂谷系特 点。东吴运动后开始的印支阶段,由于滨太平洋构造的作用,盆地轮廓 和结构发生了较大的改变,与此同时开始的哀牢山洋盆向NE方向的俯 冲消减作用。盆地再次发生张裂和扩张,从而进入弧后盆地发展阶段。 印支期末,盆地由东向西逐渐封闭,结束了右江盆地的发展历史。在不 同的发展阶段,盆地内的沉积物,也以东吴运动为界,分别由特征不同的沉积体系叠覆而成,早 期还出现典型的由非补偿性和补偿性沉积组成的双层结构。同样的盆地内的火山活动也分为 两个阶段,早期货段以碱性及碱钙性系列的基性火山岩为主,主要受NW向构造控制;晚期阶 段为钙碱性及钙性系列的基性及中酸性火山岩,同时受NW及NE向构造控制。由此可见右 江盆地是在古特提斯构造和滨太平洋构造的复合作用下形成的。
Located at the southern margin of the South China plate, the Youjiang basin has a close relation with the NW-and NE-trending syndepositional faults in respect to the configuration and structure of the basin. The evolution of the Youjiang basin progressed through two stages. In the Hercynian period, the opening of the Ailao-shan-Honghe ocean basin gave rise to a number of NW-trending rift belts in the Youjiang area. During this period, deep-water sediments were dominant and the basin was possesed of the characteristics of the rift system of passive continental margins. In the early Indosinian period after the Dongwu movement, the circum-Paci-fic tectonism led to a major change in the configuration and structure of the basin. In the meantime, the Ailaoshan ocean basin began to be subducted towards the nor. theast, thus causing the basin to be split and expand again, and then the basin developed into the stage of the back-arc basin; At the end of the Indosinian period, the basin gradually closed from east to west, thus ending up the history of development of the Youjiang basin. In the different developmental stages, sediments in the basin, also with the Dongwu movement as the boundary, were formed by superposition of sedimentation systems with different features, and a typical two-layer structure, which consisted of starved and compensated sediments, also occurred in the early stage. Likewise, volcanic activity in the basin also involved two stages. Basic volcanic rocks of alkali and alkali-calcic series, which were controlled by NW-trending faults, occurred in the early stage, and basic and intermediate-acid volcanic rocks of calc-alkali and calcic series, which were controlled by NW-and NE-trending faults, occurred in the late stage. From above it follows that the Youjiang basin was formed by the combined action of the Paleo-Tethys and circum-Pacific tectonism.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1995年第2期113-124,共12页
Acta Geologica Sinica
基金
国家自然科学基金(编号 4870132)
关键词
沉积作用
裂谷盆地
华南
右江盆地
沉积构造
sedimentation, tectonism, rift basin, back-arc basin, Youjiang basin of South China
