Tectonic Evolution And Sedimentary Characteristics Of Foreland Basin In North America

Under the instruction of Sedimentology and Tectonics, on the basis of the former researchers' achievements, this paper mainly focus on the origin and evolution of North American plate and the evolution and sedimentation of its foreland basins. It aims to provide strategic basis for national oil and gas exploration and exploitation..Through comprehensive investigation and study on the foreign bibliographic references, the reasonable evolutionary stages of North American Plate have been put forward. Overall, Phanerozoic tectonic evolution of the North American plate can be divided into three main stages: ?Cambrian tectonically stable period, in the end of the Rodinia supercontinent breakup; ?The phase of Pangea convergence from Ordovician to Permian; ?The phase of Pangea breakup from Triassic to present day.The evolution and sedimentation of the foreland basins are related to assemblage and breakup of supercontinents. In Precambrian, North America was in a stable tectonic environment, without any orogeny, so there is no foreland basin developed; The foreland basins developed universally in the Eastern North America while developed just in local area of Western North America during the phase of assemblage of Pangea from Ordovician to Permian. During the phase of Pangea breakup from Triassic to Neogene, the Pacific Plate subducted to the west of North America Plate when foreland basins started to develop universally in western North America.This thesis emphasizes on the sedimentation and tectonic evolution of Alberta basin and Appalachian basin during different periods. As a typical foreland basin in the western North America, Alberta basin stared the foreland basin evolution cycle during Jurassic period, before which Alberta basin was in the evolution cycle from passive margin basin to back arc basin and the sedimentary facies changed correspondingly from marine facies to terrestrial facies. The Appalachian basin was a passive basin from Cambrian to Ordovician and began the cycle of continental basin evolution in Silurian when sedimentary facies converted from marine facies to continent facies correspondingly.The multi-stage orogenies' effects on the north American forelands' evolution are explained in detail and the forelands differences between the east and the west part in north America are proposed simply at the same time.