摘要
南盘江盆地在早古生代加里东造山作用基础上,于海西-印支期经历了一个完整的威尔逊旋回,即由早期裂谷(D-P_1)、晚期裂谷和被动大陆边缘(P_2-T_1)、前陆盆地(T_2-T_3)。通过对该盆地南部早三叠世初期玄武岩的稀土元素分析,证实在盆地演化过程中确实有过洋壳生成。该盆地在中晚三叠世发展为前陆盆地表明,扬子板块与印支板块曾沿黑水河断裂带发生过碰撞造山。
The Napanjiang basin is tectonically located at the juncture of the Tethys and Pacific tectonic domain. In the Early Palaeozoic, as a part of the southeastern passive margin of the Yangtze Plate, had been involved in the Caledonian orogenic belt resulting from the collision of the Yangtze Plate and Huanan-Indo-Sinian Plate. In the Hercynian-Indosinian, the evolution of the basin occurred in the context of Tethys. On the basis of the sedimentary basin analysis and comprehensive study of other geologic features, this paper suggests that the tectonic evolution of the basin in the Hercynian-Indosinian stage constituted a complete Wilson cycle, consisting of the following developement stages:early rifting (D-P1),late rifting and passive margin development (P2-T1) and syncollisional orogenic foreland basin development (T2-T3).Early rifting was characterized by the formation of paleogeographical framework of a series of alternately arranged grabens and horsts resulting from NE-SW extension, accompanied by occurrence of small amount of alkaline and peralkaline basalts. Late rifting was characterized by large-scale subaerial and submarine eruption of the Emei basalt resulting from the formation and rise of the thermal mantle plume and the simultaneous strong crustal extension which resulted in the breakup of the continental crust. The REE analysis of the initial Early Triassic basalts from the southern part of the basin verifies the existence of oceanic crust in the basin evolution. Detailt-ed analysis of the foreland busin has revealed clearly that the collision occurring between the Yangtze Plate and the Indo-Sinian Plate along the Balck River fracture zone resulted in the formation of a series of complex fold-thrust zones and Klippen in northern Viet Nam and the Yao-huangshan and Yuanyangshan nappes in Napof Guangxi,China.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1996年第2期99-107,共9页
Acta Geologica Sinica
关键词
南盘江盆地
海西-印支期
裂谷
沉积
构造
演化
Nanpan Jiang basin, Hercynian-Indosinian stage, rifting, foreland basin
