西藏改则地区班公湖-怒江结合带内上三叠统的发现及其地质意义

The discovery of the Upper Triassic strata in Bangong Co-Nujiang junction zone of Gerze area in Tibet and its significance

三叠系在班公湖-怒江结合带两侧仅有少量露头。早三叠世是怒江洋盆初始演化的开始,由于晚二叠世-早三叠世大规模的海退持续和地壳的抬升,地层遭受剥蚀,整个班公湖-怒江结合带内缺乏完整的三叠系地层系统,对怒江洋的演化缺乏完整的物质记录。此次有古生物化石依据的上三叠统的发现,为探讨洋盆的演化提供了较好的依据,也为区域地层对比、地层格架建立、古环境分析等提供了基础资料。

There exist only very few outcrops of Triassic strata on both sides of the Bangong Co-Nujiang junction zone.Early Triassic period was the beginning of the initial evolution of the Nujiang Ocean basin.The large-scale continuous marine regression and crustal uplift caused the denudation of the strata;hence the whole Bangong Co-Nujiang junction zone lacks a complete Triassic stratigraphic system,and there exists no complete material record for the study of the evolution of the Nujiang Ocean.The discovery of the Triassic strata based on fossils provides an ideal basis for the study of the evolution of the Nujiang Ocean basin,and also supplies basic data to regional stratigraphic correlation,establishment of stratigraphic framework and paleoenvironment analysis.