Xinjiang Petroleum Geology ›› 2006, Vol. 27 ›› Issue (6): 688-690.

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Fault Strike and Its Significance of Plate Dynamics in Central Placanticline, Songliao Basin

GONG Fa-xiong1,2, SHAN Ye-hua1, LIN Ge1, LIU Shi-lin1,2, ZHANG De-sheng1,2   

  1. 1. Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, CAS, Guangzhou, Guangdong 510640, China;
    2. Graduate School, CAS, Beijing 100049, China
  • Received:2006-03-30 Revised:2006-05-09 Online:2006-12-01 Published:2020-10-21

Abstract: In recent years, high-precise 3D seismic explorations in central placanticline uplift of Songliao basin have revealed that the strikes of faults in this area tend to gradual migrating toward the west from the lower to the upper reflecting horizons. The top reflecting horizon T2 (dating about 98.9Ma) of Quantou formation of Cretaceous can be regarded as a reference surface, below which the strikes of major faults are NNE or SN directions, parallel to the placanticline trend; above which they are NNW directions, showing difference of about 60°between them. It is believed that such a migration of strikes represents the concordant variation of in-situ maximum horizontal principal stress, which might reflect the changes of subducted velocity of oceanic crust near continental margin. Before 120 Ma, the Izanagi plate was being subducted obliquely toward the Euro-Asia continent followed by the predominating of orthogonally subduction of the oceanic crust plate, somewhat decreasing of the velocity of the plates motion. Hence, it is suggested that compared with the oblique subduction, the orthogonal subduction could play an effective role in transmitting compressive stress from the continental margin to the interior.

Key words: Songliao basin, normal fault, strike, stress, plate motion

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