塔中地区前中生界层序地层特征与非构造圈闭

塔里木盆地塔中地区前中生界发育4级不整合面。根据不整合面发育特征，将震旦系-二叠系划分为3个I级层序、9个Ⅱ级层序和19个Ⅲ级层序。塔中地区古生界各种类型非构造圈闭的发育均与多期重大不整合面(地层削截面、超覆面、缺失面等)及层序界面密切相关，可划分为三大类10个亚类，主要分布在I级层序震旦系-下奥陶统巨层序(MSI)和中、上奥陶统-泥盆系巨层序(MS2)顶面的上、下岩性段内，规模很大，是寻找非构造油气田(藏)的重要勘探领域。图3表1参8

Sequence stratigraphic characteristic of Palaeozoic in Tazhong area, Tarim Basin

Stratigraphic sediment in the Tazhong area was of polycycle, which was controlled by previous structure movements. Four grades of unconformities had been developed in Palaeozoic in situ. According to the development feature of unconformity surface,the Palaeozoic has been divided into 3 megasequences, 8 supersequences and 19 tertiary sequences. Different kinds of non-structural traps were relevant to large unconformities developed in multiple periods (stratigraphic trunction, overlap, and lacuna surface, etc.) Three types and 10 subtypes can be divided, which are widely distributed and developed in the top sequences of I degree megasequence as Sinian-Ordovician (MS1) and Middle to Upper Ordovician and Devonian megasequence (MS2), and that should be the important domain for exploration.