Oil & Gas Geology ›› 2024, Vol. 45 ›› Issue (5): 1247-1258.doi: 10.11743/ogg20240504

• Petroleum Geology • Previous Articles     Next Articles

Basin-mountain coupling-controlled sequence stratigraphic characteristics of the Upper Triassic Huangshanjie Formation, Kuqa Depression, Tarim Basin

Zhenghe WANG1,2(), Ronghu ZHANG3,4(), Yong YUE5, Jinxiang CHENG1,2   

  1. 1.Chengdu Center of China Geological Survey (Geosciences Innovation Center of Southwest China),Chengdu,Sichuan 611230,China
    2.Key Laboratory of Sedimentary Basin and Oil and Gas Resources,Ministry of Natural Resources,Chengdu,Sichuan 611230,China
    3.Hangzhou Research Institute of Geology,PetroChina,Hangzhou,Zhejiang 310023,China
    4.Tarim Basin Research Center,Research Institute of Petroleum Exploration & Development,PetroChina,Korla,Xinjiang 841000,China
    5.Research Institute of Shanghai Branch of CNOOC (China) Ltd. ,Shanghai 200030,China
  • Received:2024-05-13 Revised:2024-07-04 Online:2024-10-30 Published:2024-11-06
  • Contact: Ronghu ZHANG E-mail:3121927631@qq. com;zrh_hz@petrochina.com.cn

Abstract:

Previous classification schemes for the third-order sequences in the Upper Triassic Huangshanjie Formation in the Kuqa Depression, Tarim Basin have different views on the nature of its internal key boundaries and the sedimentary evolution process. Following fine observation and analyses of outcrops in the Kuqa Depression, we reclassify the third-order sequences in the Huangshanjie Formation. The results indicate that the four members of the Huangshanjie Formation constitute two third-order sequences: SQ1 and SQ2. SQ1 comprises the 1st, 2nd, and 3rd members of the formation, proving thin in the east and thick in the west. SQ2 consists of the 4th member of the formation, being thick in the east and thin in the west. Both sequences contain lowstand systems tracts (LSTs), transgressive systems tracts (TSTs), and highstand systems tracts (HSTs). The third-order sequence boundaries, i.e., SB1, SB2, and SB3, correspond to the bottom boundary of the Huangshanjie Formation, the top boundary of the 3rd member of the formation, and the top boundary of the formation, respectively. SB1 and SB3 exhibit sharp transitions of lithology and lithofacies, with SB3 also identified as an erosional and depositional hiatus surface. SB2 emerges as a depositional hiatus caused by regional uplifting, and forms regional paleosol that can be correlated far away. The changes of basin-mountain coupling govern the formation of the two third-order sequences in the formation, in which the paleo-Tianshan Mountain experienced two episodes of rapid uplifting during the initial deposition of the LSTs and HSTs in SQ1, and then got eroded to peneplain at the end of SQ1 deposition. Accordingly, the basin’s sedimentary response transitions from the early intense subsidence and rapid sedimentary infilling to the stable subsidence and sedimentary infilling, and then to the second phase of intense subsidence and rapid sedimentary infilling to form the SQ1. After depositional hiatus, the basin continues to be filled steadily under the background of weak subsidence, forming SQ2.

Key words: sequence stratigraphy, basin-mountain coupling, Huangshanjie Formation, Upper Triassic, Kuqa Depression, Tarim Basin

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