秦岭三叠纪古海洋再造

RECONSTRUCTION OF THE QINLING TRIASSIC PALEO-OCEAN

在详细研究秦岭地区三叠纪生物地层、生态地层、沉积相、岩相古地理、生物古地理、地球化学及古地磁的基础上，对秦岭三叠纪海盆宽度、海盆性质进行了讨论，最后对秦岭三叠纪古海洋进行再造。认为三叠纪秦岭海为喇叭状向西开口的裂陷槽，海盆西部早三叠世宽度约１０００ｋｍ，在三叠纪由于印支运动的影响，秦岭海盆规模不断缩小，沉陷中心向南迁移，最终于晚三叠世末消退。

The Qinling orogenic belt in Northwest China,as the easternmost part of the Paleo-Tethys and transitional area between North China and Yangzte blocks, has been receiving particularly attention by many geologists in the world. Based on the detalied study of biostratigraphy, ecostratigraphy,attention by many geologists in the world. Based on the detailed study of biostratigraphy, ecostratigraphy,sedimentology and lithofacies, paleogeography, paleobiogeography, tectonic geology, paleo-magnetism and geochemistry in Qinling belt,this paper mainly deals with the nature, width and paleo-ocanographic reconstruction of the Triassic Qinling Sea. It reveals that the Triassic Qinling paleo-sea was a loudspeaker-shaped rift widened westward,during the Early Triassic,west part of it about 1000km in width. Under the influence of Indosinian orogeny, Triassic Qinling paleo-sea became narrower and narrower,the depressional center moved southward. Finally,the whole Qinling area completed uplifting and the long-existing Qinling Sea withdrawn at the end of Triassic.Such a work is not only important to understanding the evolution of Qinling orogenic belt, but also useful for systematic study of reconstruction of paleo-ocean.