塔里木盆地关键构造变革期不整合特征及其地质意义

Unconformity characteristics and geological significance in key tectonic revolution stage of Tarim Basin

塔里木盆地自奥陶纪以来,先后经历了加里东中期Ⅰ幕、加里东中期Ⅲ幕、海西早期、海西晚期、印支期、燕山中期及燕山晚期--喜马拉雅期等7次关键构造变革期,并且形成7个重要不整合界面,这些不整合具有各自不同的类型和特征。通过地震剖面识别、测井分析和岩心观察等手段分析,认为这些不整合面现今在盆地内主要表现为平行不整合、叠合不整合、褶皱不整合、断褶不整合、古岩溶和古侵蚀不整合。随着盆地的演化,这些不整合面在几何形态、空间位置和时间上不断发生变化。根据这些变化,认为塔里木盆地这些主要不整合在几何形态上具有叠合、复合特征,空间上具有分层、差异的特征,时间上表现为迁移特征。不整合与所经历的构造运动强弱,剥蚀时间长短,沉积时的气候、环境有着密切关系。

Tarim Basin suffered seven key tectonic revolution stages since 0rdovician, including the episode I of middle Caledonian, episode m of middle Caledonian, early Hercynian, late Hercynian, Indo-Chinese, mid- dle Yanshan and late Yanshan-Himalayan, and generated seven important unconformities with different types and characteristics. Through seismic profile recognition, logging analysis and core observation, the authors considered that these unconformities appeared in parallel, superimposed, folded, fault-folded, ancient karst and palaeo-erosion unconformities in type. Associated with the evolution of the Tarim Basin, unconformities changed constantly in geometric shape, space and time. According to these changes, the authors considered that the unconformities were characterized by superimposition and composition in geometric shape, lamination and difference in space, and migration in time. The unconformities characteristics in Tarim Basin had close relationship with tectonic movement, erosion time and palaeo-sedimentary environment.