AAPG PSDG Webinar: "Deformation of the Qaidam Basin" By Yanpeng Sun скачать в хорошем качестве

AAPG PSDG Webinar: "Deformation of the Qaidam Basin" By Yanpeng Sun

Deformation of the Qaidam basin based on regional seismic cross-sections and its implications for tectonics of the Tibetan Plateau Yanpeng Sun1*, John H. Shaw1, Shuwei Guan2 1 Harvard University 2 PetroChina *Current affiliation: Shell USA, Inc. The Qaidam basin is located at the northern margin of the Tibetan Plateau, the largest convergent tectonic feature on the Earth. As the Qaidam basin is one of the few places in the Tibetan Plateau that retain a significant Cenozoic sedimentary sequence and these strata have undergone substantial folding under active contractional tectonics, the basin provides a unique opportunity to constrain the style and timing of deformation in this part of the Plateau. Accurate definition of structural styles in the basin is important for understanding the regional tectonics and guiding industry exploration efforts. Despite some recent discoveries in the basin, a large part of the basin remains unexplored. Exploration efforts have been limited partly by a lack of understanding of the structural styles and their influence on the petroleum system, as the Qaidam basin has undergone significant folding over the Cenozoic Era, forming as many as 140 surface and blind anticlines. Thus, a detailed structural characterization of the geometry, timing, and kinematics of structures will help guide the hydrocarbon exploration efforts in the basin. Based on the interpretation of regional seismic sections that extend across the basin and detailed analysis of more than 45 geological structures, we describe the basin-scale deformation style and timing, and explore the implications of these findings for understanding of the regional tectonics. Our interpretation results indicate that the basin is controlled by both northeast and southwest dipping basement involved thrust faults that typically form fault-propagation folds and structural wedges. The deformation of these structures records two phases of deformation. The first initiated in Late-Eocene shortly after the India-Asia collision and represents deformation that occurred far from the plate boundary, possibly localized on pre-existing normal faults. The second phase began from Miocene associated with the emergence of the Kunlun and Altyn Tagh Ranges and associated eastward extrusion of tectonic blocks within the Tibetan Plateau. Thus, deformation in the Qaidam basin records the transition from north-south convergent to escape tectonics in the Tibetan Plateau. Bio: Yanpeng Sun holds a Ph.D. degree in Structural Geology and Earth Resources at Harvard University, and the research work related to this talk was completed while there. His research interests included structural interpretation, kinematics, and geomechanics of fold-thrust belts, as well as basin analysis. Yanpeng currently works for Shell USA, Inc. as an exploration geoscientist focusing on the deepwater Gulf of Mexico exploration.