塔里木盆地下古生界碳酸盐岩层序及沉积演化特征

Sequence and sedimentary evolution characteristics of Lower Paleozoic carbonate rock in Tarim Basin

塔里木盆地震旦纪晚期开始呈现西台东盆的碳酸盐岩沉积格局,至中奥陶世完成下古生界碳酸盐岩台地建设。在区域构造运动研究基础上,利用钻(测)井、露头资料,综合年代地层、岩石地层、生物地层及地震地层,识别盆地下古生界碳酸盐岩层序界面特征,划分出5个二级层序,并分析层序内部沉积演化特征,建立起全盆地层序地层格架。盆地层序格架内的碳酸盐岩台地演化过程中,发育缓坡型、弱镶边型、镶边型以及淹没型4种台地类型。沉积模式归结为4种,即蒸发、局限台地—台缘—斜坡—陆棚—欠补偿盆地模式;局限台地—台缘—斜坡—陆棚—欠补偿盆地模式;开阔台地—台缘—斜坡—陆棚—欠补偿盆地模式;开阔(淹没)台地—台缘—斜坡—(混积)陆棚—浊积盆地模式。

The construction of Dower Paleozoic carbonate platform in Tarim Basin began to build at late Sinian, and finished at Middle Ordnvician. Existing data show the sedimentary framework can be considered up as ＂Western Platform, Eastern Basin＂ at that time. On the basis of regional tectonic movement analysis, well drilling, logging and outcrop data are used to identify the sequence boundary of Paleozoic carbonate rocks. And five supersequences are divided, combined with chronostratigraphy, lithostratigraphy, biostratigraphy and seismic stratigraphy. The sedimentary evolution characteristics within whole basin sequence stratigraphic framework display that the evolution of carbonate platform develops four kinds of platform types, which are gentle slope type, weak-rim type, rim type and submerged type. Depositional model can also be attributed to four kinds, including evaporation, limited platform-platform margin-slope-shelf-undercompensation basin mode; limited platform-platform margin-slope- shelf-undereompensation basin mode; open platform-platform margin-slope-shelf-undercompensation basins mode; open（submerged） platform-platform margin-s＇lope-mixed shelf-turbidite basin modes.