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Sequence stratigraphy and sedimentary evolution of Lower Cretaceous series in Chepaizi area, northweastern margin of Junggar Basin |
YANG Yong1, CHEN Shi yue1, XIANG Kui2, YANG Jun sheng1
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(1.School of Geosciences in China University of Petroleum, Qingdao 266555, China;2.Xinjiang Exploration and Development Center, Shengli Oilfield, Dongying 257017, China)
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Abstract: |
Based on the theory of sequence stratigraphy, the sequence stratigraphy and sedimentary evolution of Lower Cretaceous series in Chepaizi area, northweastern margin of Junggar Basin were studied by comprehensive application of seismic data, drilling data, logging, outcrop data, paleontological data and well seismic calibration. The results show that the Lower Cretaceous can be divided into two third order sequences .The lower part of sequence KSI develops well. The lowstand system tract (LST) is dominated by braided river and fan delta. The feature of down cutting valley is obvious. Transgressive system tract (TST) is mostly made up of shoreface/offshore deposits. The highstand system tract (HST) mostly consists of fan delta and shoreface/offshore deposits. The top part of sequence KSII can be classified into 2 system tracts. The TST is made up of shoreface/offshore deposits. The HST mainly consists of meandering river, fan delta and shoreface/offshore deposits in the condition of the slowly falling lake level and gradually decreasing supply of terrestrial clastic. The sedimentary construction of Lower Crataceous shows that sediment evolution of the research square has the character of cyclicity. The ancient climate change of Lower Cretaceous plays an important role during the sequence development. |
Key words: sequence stratigraphy sedimentary evolution Junggar Basin Chepaizi area Lower Cretaceous |
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