--> Controls from the Formation and Evolution of the Nonmarine Songliao Basin, Northeast China, Feng, Zhiqiang; Jia, Chengzao; Zhang, Shun; Feng, Zihui; Zheng, Min, #90100 (2009)

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Controls from the Formation and Evolution of the Nonmarine Songliao Basin, Northeast China

Feng, Zhiqiang1
 Jia, Chengzao2
 Zhang, Shun1
 Feng, Zihui1
 Zheng, Min2

1Daqing Oilfield Lmt., PetroChina, Daqing, China.
2
PetroChina,
Beijing, China.

The Songliao Basin in northeast China is the largest and most productive oil-bearing nonmarine basin in China. Research on the formation and evolution of extensional basins can provide not only a framework for predicting the occurrence and distribution of source, seal and reservoir rocks, but also useful information to improve our understanding about geodynamic processes and regional plate tectonism. Many researchers have discussed the origins of the Mesozoic Songliao basin. The subduction of Pacific Plate has been considered as the dominant controls. Here, effects from the Okhotsk Sea are emphasized.

Through tectonostratigraphic analysis of the Songliao basin, four episodes of deformation are recognized: crustal doming, rifting, postrift thermal subsidence, and structural inversion. The first period of deformation occurred during the Middle and Late Jurassic when asthenospheric upwelling heated, thinned and stretched the lithosphere. These events may have been caused by the narrowing of the
Okhotsk Sea and attendant lithospheric subduction. The second rifting episode began in the latest Jurassic and continued into the Early Cretaceous. It resulted in the formation of a large number of isolated fault blocks, which are filled with thick volcanic rocks interbeded with coal-bearing fluvial and lacustrine strata. Rifting may have been caused by the formation and subduction of the Izanagi and Pacific Plates. During this stage, the crust in the Songliao area was further thinned and heated. The third phase of regional postrift subsidence, which began with the Lower Cretaceous, was caused by lithospheric cooling, but modulated by multiple compressional events. These compressional events, which episodically interrupted the long term cooling subsidence, originated from the Okhotsk suture and the Pacific plate. In the early Cretaceous, strong compressions originated by the closure of Okhotsk Sea, and formed the mountain ranges of Daxinganling, which provided plentiful sediment to the northern part of the basin. In the Late Cretaceous, the intensity of compression from the Pacific side increased through time, causing westward migration of depocenters and uplift in the east until the end of Cretaceous. The forth stage is structural inversion, including folding and uplift, pushed by the Pacific Plate, which began at the later stage of Cretaceous through Tertiary.


AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil