摘要
衔接秦、祁、昆造山带的鄂拉山北北西向造山带中段的哇洪盆地,位于哇洪山—温泉右行走滑断裂东侧,为一较典型的晚三叠世拉分沉积—火山盆地。其内沉积的鄂拉山组,含标准的晚三叠世植物,火山岩同位素测年也属同期。沉积特征研究表明,该盆地经历了拉分—退积、拉深—火山活动以及推挤—进积三个充填阶段,而且其充填过程是在盆地不断变形变位的动态中完成,形成总厚度达2635m的火山沉积地层。哇洪拉分盆地的充填机制、变形变位研究可给鄂拉山造山带在晚三叠世时期的演化研究提供较可靠的依据。
Wahong basin, as the joining place of Qingling, Kunlun and Qilian orogenic belt, lied in the middle of NNW-trend Ngolashan orogenic belt and in the east side of Wahong mountain -Wenquan right strike-slip fault, is a typical Late Triassic pullapart sedimentary-volcanic basin. In Ngolashan formation, which deposited in the basin, the plant fossil and the isotopic determination both demonstrate that it is belong to Late Triassic. The study of sedimentary feature show that the basin underwent three filling stages, i.e. pullapart retrogradation, deeping volcanic activity and push-progradation. The filling of the basin was completed in the dynamic state of continuous disformation and dislocation and resulted in volcano-sedimentary strata with thickness of 2635m. So the study of filling mechanism and disformation-dislocation of Wahong pullapart, basin would provide reliable basis for the study of Ngolashan orogenic belt evolved in Late Triassic period.
