塔里木盆地塔中和满西地区石炭系层序地层

Sequence stratigraphy of the Carboniferous in Tazhong and Manxi areas of Tarim Basin

应用地震、钻井、测井、岩芯及分析化验资料,将塔里木盆地塔中和满西地区石炭系划分为3个地震地层层序与6个沉积层序,其中CⅠ与CⅡ层序为Ⅰ型层序,CⅢ～CⅥ层序为Ⅱ型层序。与标准的Ⅰ型层序比较,区内Ⅰ型层序低位体系域以河流沉积体系为特征,缺失盆底扇、斜坡进积复合体等深水沉积体系;Ⅱ型层序中陆架边缘体系域不发育,主要的沉积体系以浅水碳酸岩台地和海岸平原为特征。石炭系早期层序形成在起伏不平的剥蚀面之上,以填平补齐的充填沉积为主,中后期层序则发育在宽阔平坦的盆地内。这种层序格架明显不同于被动大陆边缘经典型的层序格架,反映了稳定地块内坳陷性盆地的层序特点。

Using the seismic data, drilling, well-logging and well core, combined with the analysis data, the carboniferous are divided into three seismic sequences and six sedimentary sequences. The sequence (CⅠ) and (CⅡ) are the typeⅠsequence, while the CⅢ to CⅥ are the type Ⅱ sequence. By comparison with the standard typeⅠsequence, the LST of typeⅠsequence in the areas are characterized with the river deposit, and lack of the deep water deposition system such as basin floor fans and slope transgress complex. In the type Ⅱ sequences, the SMST are not well-developed, and the main deposit systems are the shallow water carbonate deposit and the sea margin plain deposit. The sequences that formed in the early Carboniferous are on the uneven erosion surface, and the main deposition style is that of filling the surface; while during the middle and latter Carboniferous, the sequences are formed in the broad and even basin. This kind of sequence framework is different from the classic one that derived from the passive continental margin, and reflects the sequence that is developed in the depression basin of the stable platform.