黔中地区多期构造演化、差异变形与油气保存条件

Poly-cycle Tectonic Evolution,Differential Deformation and Hydrocarbon Reservation of Central Guizhou and Adjacent Region

黔中地区构造演化经历了基底、原特提斯、古特提斯和新特提斯等四大旋回,进一步划分为早期裂谷(前南华纪)、台地-被动大陆边缘(南华纪—志留纪)、台地-陆内裂谷(泥盆纪—二叠纪)、稳定台地(早、中三叠世)、陆相断陷(晚三叠世—古近纪)和断褶隆升(新近纪—第四纪)等6个阶段。控制黔中地区构造—沉积格局的关键构造变革期为:都匀运动、广西运动、印支中期运动、燕山晚期运动和喜马拉雅运动。黔中地区差异构造变形特征十分明显,自东往西可以划分为4个构造带,即雪峰构造带、麻江-凯里构造带、黔中构造带和黔西北构造带等。受NW—WNW向展布的构造转换带控制,黔中地区在南北方向上具有构造分段性特征。黔中地区具有盖层多样性特征,主要发育3类盖层,即盐岩、泥页岩和致密碳酸盐岩。盐岩类盖层分布局限。构成区域性封盖条件的泥页岩主要分布在下寒武统(牛蹄塘组和金顶山组)和中下志留统(翁项群),分布较稳定。致密碳酸盐岩盖层可能以下寒武统清虚洞组灰岩和泥灰岩最为有利。

Central Guizhou and its adjacent areas experienced basement, proto-Tethys, paleo-Tethys and neoTethys tectonic cycles. The six structural stages have been further recognized as following, the early rift stage, platform-passive margin stage （Nanhuanian -Silurian）, platform-intra-continental rift stage （Devonian-Permian）, stable platform stage （early- to mid-Triassic）, continental fault-depression stage （late Triassic-Paleogene）, and fault-fold rise stage （Neogene-Quaternary）. The key tectonic changes controlling the tectono-stratigraphic framework of the Central Guizhou and adjacent areas are the Duyun, Guangxi, Central Indosinian, Late Yanshanian and Himalayan movements. The structures in study areas are characterized by differential deformation. Four structural belts can be recognized as the Xuefeng, Majiang-Kaili, Qingzhong and northwest Guizhou tectonic belt. The structural segmentation, controlled by a series of NW-WNW transfer zones, is also apparent in this district. Three types of cap-rocks may develop in tile Central Guizhou and adjacent areas as following： salt rock, mudstone and shale, and condensed sandstone. The distribution of salt rock is limited in the area. The regional caprocks with good reservation are mudstone and shale of the Lower Cambrian and Mid-Lower Silurian, as well as Qingxudong Formation limestone and marl of the Lower Cambrian.