Chapters authored
Structural Differentiation and Sedimentary System of the Permian Sichuan Cratonic Basin
The Sichuan Basin located in the western region of the Yangtze block was a stable craton basin in the Permian. The structural differentiation caused by the Dongwu movement and the Emei rifting activity controlled the sedimentary system and the Permian carbonate gas reservoirs in the Sichuan Basin. In this study, we have investigated the stratigraphic characteristics of each Permian formation, studied the depositional systems of each period of the Permian stage, and discussed the overall tectono-sedimentary evolution of the sedimentary basin. During the Permian, the Sichuan Basin experienced an intense tectonic activity, controlling the variations of the sedimentary environments occurring in the basin. The depositional systems of the basin were controlled by the tectonic setting of the intra-cratonic depression and marginal rifts during the period. Therefore, this is an important period in the tectono-sedimentary evolution of the study area, which can be divided into the following stages: (1) From the Late Carboniferous to the Early Permian, the Sichuan Basin was dominated by tectonic uplift and denudation. In the Middle Permian, a regional transgression occurred in the whole upper Yangtze region, and the sedimentary environments of the Sichuan Basin and its adjacent areas gradually changed to the carbonate platform. (2) In the early phase of the Late Permian (the Wujiaping period), being influenced by the Emei rift, the Sichuan Basin and its adjacent areas formed a complex pattern of structural highs and adjacent depressions, controlled by a differential subsidence. (3) In the late phase of the Late Permian (the Changxing period), with the cessation of the volcanic activity and the enhancement of the regional extension, the pattern of structural highs and depressions is more obvious, and the relatively calm structural environment makes the carbonate sedimentary environment tending to dominate.
Part of the book: Geochemistry
Late Neo-Proterozoic Tectono-Sedimentary Evolution of the Tarim Block, NW China
The study of the late Neo-Proterozoic tectono-sedimentary evolution of the Tarim Basin is a key to unravel the tectonic setting, the intracontinental rift formation mechanism, and the sedimentary filling processes of this basin. Since in the Tarim Basin, the late Neo-Proterozoic to early Cambrian sedimentary successions were preserved, this basin represents an excellent site in order to study the Precambrian geology. Based on the outcrop data collected in the peripheral areas of the Tarim Basin, coupled with the intra-basinal drill sites and seismic data previously published, the late Neo-proterozoic tectono-sedimentary evolution of the Tarim Basin has been investigated. These data show that there were two individual blocks before the Cryogenian Period, namely, the north Tarim Block and the south Tarim Block. In the early Neo-Proterozoic (ca. 800 Ma), the amalgamation of two blocks resulted in the formation of the unified basement. During the late Neo-Proterozoic, the Tarim Block was in an extensional setting as a result of the Rodinia supercontinent breakup and then evolved into an intracontinental rift basin. The tectono-sedimentary evolution of the basin may be divided into three stages: the rifting stage (780–700 Ma), the rifting to depression transitional stage (660–600 Ma), and the post-rift depression stage (580–540 Ma). In the rifting stage, intracontinental rifts (i.e., the Awati Rift, the North Manjar Rift, and the South Manjar Rift) were formed, in which coarse-grained clastic sediments were deposited, generally accompanied by a massive volcanic activity due to an intensive stretching. In the rifting-depression transitional stage and in the post-rift depression stage, the paleogeography was characterized by uplifts to the south and depressions to the north. Three types of depositional association (i.e., clastic depositional association, clastic-carbonate mixed depositional association, and carbonate depositional association) were formed. The distribution of the lower Cambrian source rock was genetically related to the tectono-sedimentary evolution during the late Neo-Proterozoic. The lower Cambrian source rock was a stable deposit in the northern Tarim Basin, where the late Ediacaran carbonate was deposited, thinning out toward the central uplift. It was distributed throughout the entire Mangar region in the east and may be missing in the Magaiti and the southwestern Tarim Basin.
Part of the book: Geochemistry