塔里木早古生代原盆地古隆起地貌和古地理格局与地层圈闭发育分布

Paleohigh geomorphology and paleogeographic framework and their controls on the formation and distribution of stratigraphic traps in the Tarim Basin

塔里木盆地早古生代的古构造格局以发育一系列横跨盆地的大型北西西或北东东向展布的古隆起带为特征。盆地不同的演化阶段隆坳格局发生过重要变化,导致了盆内构造古地理格局的不断变迁。盆地中部的古隆起带是在中奥陶世盆地从离散背景转向挤压背景时形成的,由和田河东和塔中等古隆起组成,具有复杂的构造古地貌。早古生代的古隆起地貌可划分出高隆带、隆起边缘斜坡和坡折带、陆棚斜坡和低凸起平台、陆架坡折带以及深海盆地或平原等构造古地貌单元。塔北古隆起南斜坡、中央古隆起南、北两侧的斜坡边缘坡折带均对礁、滩等高能相带的发育分布起重要的控制作用。从古隆起到古坳陷带,碳酸盐岩台地边缘的斜坡坡折带、削蚀不整合和上超不整合三角带等是形成重要岩性地层圈闭的有利区带。

The palaeotectonic framework of the Tarim basin in the Early Paleozoic was characterized by develop-ment of a series of large-scale, NWW or NEE trending uplifts. The configuration of the uplifts and the depres-sions varied significantly and resulted in the change of the tectonic paleogeography of the basin. The paleohigh belt in the central basin was formed when the basin shifted from divergence to compression since the Middle Ordovician. It comprises the Hetianhedong and Tazhong palaeo-uplifts with complex paleogeomorphology. Several typical geomorphologic units have been recognized in the early Paleozoic paleohighs, including the uplift high, marginal slope and slopebreak, shelf gentle slope and lower rise or platform, shelf slopebreak and deep-sea basin or plain. The southern marginal slopebreak zone of the Tabei paleohigh, and both the northern and southern slopebreak zones flanking the Tazhong paleohigh controlled the development of high-energy facies of reef and shoal deposits. From the paleohighs to the paleo-depression belt, the marginal slopebreak zones of carbonate plat- forms,triangle zones of truncated and onlap unconformities are favorable for the formation of lithologic-strati-graphic traps.