塔里木盆地塔北隆起区中生界沉积演化特征

Evolution of Mesozoic sedimentary fill in the Tabei Uplift region， Tarim Basin

吴高奎 张忠民 林畅松 田纳新 左小军 李浩 孔凡军 李军

Gaokui Wu Zhongmin Zhang Changsong Lin Naxin Tian Xiaojun Zuo Hao Li Fanjun Kong Jun Li

针对塔里木盆地塔北隆起区中生界层序地层划分和沉积充填演化认识不够明确的问题，综合地震、测井、岩心和露头资料，重新厘定了层序地层格架，识别了主要的沉积体系类型，揭示了沉积充填演化特征及其与塔北隆起中生代隆升－衰亡过程的响应关系，共识别出4个区域性角度不整合、1个区域性平行不整合和7个局部不整合，并据此将中生界划分为4个二级层序（Ⅰ—Ⅳ）和11个三级层序。晚三叠世（Ⅰ-SQ3），东西走向的塔北隆起提供了大量物源，北坡陡而南坡缓，分别发育冲积扇/扇三角洲和辫状河三角洲沉积；早侏罗世（Ⅱ-SQ1），塔北隆起范围增大，物源供给增多，地势宽缓的南坡发育更大规模的辫状河三角洲沉积；白垩系卡普沙良群沉积末期（Ⅲ-SQ4），塔北隆起主体消亡，主要发育三角洲沉积（物源来自东南部大陆蚀源区）；白垩系巴什基奇克组沉积末期（Ⅳ-SQ3），研究区演变为南倾斜坡，主要发育浅水辫状河三角洲沉积（物源来自东部大陆蚀源区及北部造山带）。研究结论有助于深化对塔北隆起区中生代陆相湖盆沉积充填演化的认识，也可为油气勘探提供借鉴。

To enhance the Mesozoic sequence stratigraphic division and sedimentary fill evolution reconstruction in the Tabei Uplift region of the Tarim Basin， an integral analysis of seismic， logging， core and outcrop data is carried out to redefine the sequence stratigraphic framework， identify the major sedimentary systems and reveal the sedimentary fill evolution features and their correspondence to the emergence and disappearance of the Tabei Uplift. Four second-order sequences （Ⅰ-Ⅳ） and eleven third-order sequences are divided with the recognition of four regional angular unconformities， one regional parallel unconformity and seven local unconformities in the study area. Analyses indicate that during the Late Triassic （Ⅰ-SQ3）， the EW-trending Tabei Uplift provided abundant sediments to its steep narrow north slope and gentle broad south slope where alluvial fan/fan deltas and braided deltas were formed respectively. During the Early Jurassic （Ⅱ-SQ1）， the uplift expanded and provided more sediments to the south slope where larger braided deltas were developed. By the end of deposition of the Lower Cretaceous Kapushaliang Group （Ⅲ-SQ4）， the uplift was mostly disappeared and sediments in the area were mainly sourced from a denuded zone in the southeast and deposited as deltas. By the end of the Lower Cretaceous Bashijiqike times （Ⅳ-SQ3）， the study area turned into a south-dipping slope with sediments mostly sourced from a denuded zone in the east and an orogenic belt in the north and deposited as a shallow-water braided delta. This study may help understand the depositional evolution of the Mesozoic continental lacustrine basin in the region and provide a reference for future exploration.

10.11743/ogg20220409