吉林中部地区二叠纪岩相古地理及沉积构造背景

Permian Sedimentary Facies,Palaeogeography and Tectonic Background in Central Jilin Province,China

以沉积体系研究为基础,综合应用沉积岩碎屑物质成分统计、岩石地球化学分析等方法,详细地研究了吉林中部地区二叠纪沉积特征。结合沉积构造背景分析,重建吉林中部地区二叠纪岩相古地理及构造古地理。研究发现:早—中二叠世吉林中部地区具活动大陆边缘的复合边缘海盆特征,早二叠世发育了碳酸盐岩陆架、陆架边缘沉积体系及(次)深水盆地沉积体系,相序具有向上变浅的旋回特征;中二叠世初期,地壳活动强烈,火山发育,其后沉积了盆缘冲积扇沉积体系、(次)深水盆地沉积体系以及向上变浅的碳酸盐缓坡沉积体系等;晚二叠世东北中、小板块群与华北板块沿西拉木伦河—长春—延吉缝合带拼合,古地理发生重大变化,整个地区由海相环境转为陆相环境,仅局部地区有残留的海水,发育了湖缘冲积扇、次深湖沉积体系。

Based on the analyses of sedimentary systems, mineralogy and geochemistry, this paper discusses the sedimentary features of the Permian System in the central Jilin Province, and then the sedimentary paleogeography and tectonogeography have been recovered, in coincidence with the existing tectonogeographical models. The central Jilin Province was of a complex marginal basin along an active continental margin in the Early and Middle Permian. The Lower Permian System is composed of a shallowing-upward succession, including sedimentary systems of a shelf, a marginal sedimentary basin, and a sub-deep sedimentary basin. At the beginning of the Middle Permian, an active tectonic setting was evinced by the development of volcano-clastics in the region, followed by sedimentary systems of alluvium fans, sub-deep basin and a shallowing-upward carbonate ramp. Because of the collisions of the North China block with relatively small blocks from northeastern China along the West Lamulun RiverChangchun-Yanji suture zone, major environments dominated in the region paleogeographical change took place during the Late Permian. Terrestrial during the Late Permian, including sedimentary systems of lacustrine alluvial fans and sub-deep lakes. Remaining marine environments were confined at some places.