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Geoscience ›› 2017, Vol. 31 ›› Issue (02): 290-301.

• Stratigraphy • Previous Articles     Next Articles

High-Resolution Sequence Stratigraphy Research for Xujiahe Formation of the Upper Triassic Series in Sichuan Basin

TAN Cong1(), YU Bingsong1(), RUAN Zhuang1, HAO Shilong1, LI Kun1, LUO Zhong2, LIU Runda1   

  1. 1. School of Earth Sciences and Resources,China University of Geosciences, Beijing 100083, China
    2. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083,China
  • Received:2016-10-22 Revised:2017-01-03 Online:2017-04-10 Published:2017-04-25

Abstract:

In order to further understand the sequence stratigraphic framework and spatial and temporal distribution of Xujiahe Formation in Sichuan Basin, based on the high-resolution sequence stratigraphy and sedimentology theory, and in combination with the data of a large number of outcrops, drilling cores, well logging and seismic, this paper studied the high-resolution sequence stratigraphy and sedimentary facies of Xujiahe Formation in Sichuan Basin.Research found that despite the complexity of structure, the different direction of the material supply,the change of rock facies belts and different naming system in each partition,there are traceable unconformity and maximum flooding surface which enable the study went on.Through the sequence boundary tracking and analysis of sedimentary cycle,Xujiahe Formation can be divided into 3 super long-term cycles,6 long-term cycles and 21 middle-term cycles.According to the sequence stratigraphy contrast in the whole Sichuan Basin,the thickness of north-south strata is stable, however, east-west strata distribution is complex. The whole LSC6 and most of LSC5 are absent in the west, while most of LSC1 is absent in the east. Because the settlement-deposition center is located at the Longmenshan frontal depression, and the sedimentary rate is very high in the west of the basin, the overall distribution of the sedimentary body present like a wedge, which is thick in the west and thin in the east.On the basis of the study of sequence stratigraphy, chronostratigraphic framework was tentatively created.Through the comprehensive comparison of sequence stratigraphy, chrono-stratigraphy and biostratigraphy,the relative age of each cycle and the value of the unconformity sedimentary interval are concluded.This provides theoretical support for the next step of production and practices in Sichuan Basin.

Key words: Sichuan basin, Xujiahe Formation, high-resolution sequence stratigraphy, base level circle, time-sequence stratigraphic framework

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