Extensional detachment structures in the Lower Yangtze region

From the Late Cretaceous to Paleogene, the Pacific Plate subducted from south to north. As a result, the East Asia Continent was sheared. Large-scale left-lateral strike-slip movements from south to north and extensional detachment movements which caused the thinning of the crust took place in the Lower Yangtze region (the area to the east of Tanlu Fault, including the northern Jiangsu and South Yellow Sea regions). Three NE-EW oriented rift basin zones developed, including:(1) the Nanling-Guangde and Jurong-Changzhou rift basins in Jiangsu and the southern Anhui; (2) the Dongtai and Funing depressions in the northern Jiangsu and the Qingdao Depression in the southern South Yellow Sea Basin; (3) the Yantai Depression in the northern South Yellow Sea Basin. These basin zones had half-graben structures which were faulted in the south and onlapping in the north. They arranged like dominos from south to north, and formed basin and range structures together with the EW oriented Nanjing-Nantong-Wunansha and Binhai-South Yellow Sea uplifts. These tectonic activities reformed the marine Paleogene basins in the Lower Yangtze region. Marine source rocks in the Paleogene might be deeply buried after uplifting and erosion, which made secondary hydrocarbon generation possible and controlled hydrocarbon generation and distribution in the Miocene.