Title: TECTONIC EVOLUTION OF THE SU-WAN BLOCK, CREATION OF THE SU-LU OROGEN AND OROGENESIS COUPLED BASIN DEVELOPING
Abstract: The Tan Lu fault zone was once a transform fault in the Paleotethyan ocean, which separated the North China Craton and the Yangtze Craton to the west of the fault from the Jiao Liao (abbreviated from Shandong Liaoning) Craton and the Su Wan (abbreviated from Jiangsu Anhui) Block to the east of the fault. In other words, the latter two were tectonic units indenpendent of the North China and Yangtze Cratons respectively during the period of Tethyan evolution. The Su Wan Block was, originally, attached to the Sino Korea tectonic domain. The Su Lu (abbreviated from Jiangsu Shandong) Ocean opened in Middle Proterozoic, which accompanied with the Su Wan Block drifting far away from the Jiao Liao Craton, and turning over to the South China tectonic domain since Late Proterozoic. Controlled by the dextral strike slipping of the Jiangnan and Jiang Shao faults in strike of NEE WE, the Su Wan and Huaiyu Blocks became a median mass in the Paleotethyan ocean during the latest Carboniferous, Permian and Triassic, which was evidenced by the Early Permian Gondwana affinity or mixed Yangtze Gondwana fauna, the oxygen carbon isotopes influenced by the glacial activities in Gondwana, the Late Triassic phytocoenosis indicating a tropical subtropical environment, etc. The creation of the East Asian Yanshanides was constrained by two geodynamic systems. One was subduction and closure of the Su Lu ocean and followed continent continent collision of the Su Wan Block and the Jiao Liao Craton. Another was earlier shearing (left lateral) and later compression of the Jiangnan and Jiang Shao faults so that an oblique convergent and shear orogenesis occurred between the Su Wan Block and the amalgamated Yangtze North China Craton, and the Huaiyu Block obducted and overstacked the Su Wan Block. The Mesozoic orogenesis could be divided into five episodes, namely, the Indosinian subduction type orogenesis (the Nanxiang movement), the Early Middle Jurassic oblique convergent one (the Ningzhen movement), the Late Jurassic Early Cretaceous subduction and closure of the Su Lu Ocean, the Early Cretaceous collision and shearing orogeneses, and the orogen collapse in the latest Early Cretaceous and Late Cretaceous (the Maoshan movement). Every episode of Mesozoic orogenesis was evidenced by igneous activities, thrust or sliding thrust structures and unconformable contacts. The volcano sedimentary basin coupled every episode of Mesozoic orogenesis was illustrated, the tectonic settings, spatial temporal distributions and formation characters of the basins were concluded. The relation between orogenic movement and basin developing set up by the Yanshanian orogenesis was decoupled by a rapid collapse of the Yanshanides, and the Tertiary extensional basins in east China overlapped, directly, the collapse rifts of the Yanshanides, which was obviously different from the West China, where the coupling relation between orogenic movement and basin developing set up by the Indosian orogenensis was inherited during the Yanshanian period, and decoupled by the Himalayan orogenesis.
Publication Year: 2003
Publication Date: 2003-01-01
Language: en
Type: article
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Cited By Count: 5
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