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SHANG Zhilei,XIE Xinong,LI Xushen,ZHANG Daojun,HE Yunlong,YANG Xing,CUI Mingzhe. 2015. Difference in full-filled time and its controlling factors in the Central Canyon of the Qiongdongnan Basin. Acta Oceanologica Sinica, 34(10):81-89
Difference in full-filled time and its controlling factors in the Central Canyon of the Qiongdongnan Basin
Difference in full-filled time and its controlling factors in the Central Canyon of the Qiongdongnan Basin
Received:June 25, 2014  Revised:January 18, 2015
DOI:10.1007/s13131-015-0717-5
Key words:South China Sea  Qiongdongnan Basin  Central Canyon  sedimentary filling  full-filled time
中文关键词:  South China Sea  Qiongdongnan Basin  Central Canyon  sedimentary filling  full-filled time
基金项目:The National Natural Science Foundation of China under contract Nos 41372112 and 91028009; the National Key Projects of Oil and Gas under contract No. 2011ZX05025-002-02; the Open Fund of Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education under contract No. TPR-2012-05.
Author NameAffiliationE-mail
SHANG Zhilei Key Laboratory of Tectonics & Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan 430074, China  
XIE Xinong Key Laboratory of Tectonics & Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan 430074, China xnxie@cug.edu.cn 
LI Xushen Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China  
ZHANG Daojun Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China  
HE Yunlong Key Laboratory of Tectonics & Petroleum Resources of Ministry of Education, China University of Geosciences, Wuhan 430074, China  
YANG Xing Hubei Shale Gas Development Co., Ltd., Wuhan 430070, China  
CUI Mingzhe Bohai Oilfield Research Institute, Tianjin Branch of CNOOC Limited, Tianjin 300452, China  
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Abstract:
      Based on the interpretation of high resolution 2D/3D seismic data, sedimentary filling characteristics and full-filled time of the Central Canyon in different segments in the Qiongdongnan Basin of northwestern South China Sea have been studied. The research results indicate that the initial formation age of the Central Canyon is traced back to 11.6 Ma (T40), at which the canyon began to develop due to the scouring of turbidity currents from west to east. During the period of 11.6-8.2 Ma (T40-T31), strong downcutting by gravity flow occurred, which led to the formation of the canyon. The canyon fillings began to form since 8.2 Ma (T31) and were dominated by turbidite deposits, which constituted of lateral migration and vertical superposition of turbidity channels during the time of 8.2-5.5 Ma. The interbeds of turbidity currents deposits and mass transport deposits (MTDs) were developed in the period of 5.5-3.8 Ma (T30-T28). After then, the canyon fillings were primarily made up of large scale MTDs, interrupted by small scale turbidity channels and thin pelagic mudstones. The Central Canyon can be divided into three types according to the main controlling factors, geomorphology-controlled, fault-controlled and intrusion-modified canyons. Among them, the geomorphology-controlled canyon is developed at the Ledong, Lingshui, Songnan and western Baodao Depressions, situated in a confined basin center between the northern slope and the South Uplift Belt along the Central Depression Belt. The fault-controlled canyon is developed mainly along the deep-seated faults in the Changchang Depression and eastern Baodao Depression. Intrusion-modified canyon is only occurred in the Songnan Low Uplift, which is still mainly controlled by geomorphology, the intrusion just modified seabed morphology. The full-filled time of the Central Canyon differs from west to east, displaying a tendency of being successively late eastward. The geomorphology-controlled canyon was completely filled before 3.8 Ma (T28), but that in intrusion-modified canyon was delayed to 2.4 Ma (T27) because of the uplifted southern canyon wall. To the Changchang Depression, the complete filling time was successively late eastward, and the canyon in eastern Changchang Depression is still not fully filled up to today. Difference in full-filled time in the Central Canyon is mainly governed by multiple sediment supplies and regional tectonic activities. Due to sufficient supply of turbidity currents and MTDs from west and north respectively, western segment of the Central Canyon is entirely filled up earlier. Owing to slower sediment supply rate, together with differential subsidence by deep-seated faults, the full-filled time of the canyon is put off eastwards gradually.
中文摘要:
      Based on the interpretation of high resolution 2D/3D seismic data, sedimentary filling characteristics and full-filled time of the Central Canyon in different segments in the Qiongdongnan Basin of northwestern South China Sea have been studied. The research results indicate that the initial formation age of the Central Canyon is traced back to 11.6 Ma (T40), at which the canyon began to develop due to the scouring of turbidity currents from west to east. During the period of 11.6-8.2 Ma (T40-T31), strong downcutting by gravity flow occurred, which led to the formation of the canyon. The canyon fillings began to form since 8.2 Ma (T31) and were dominated by turbidite deposits, which constituted of lateral migration and vertical superposition of turbidity channels during the time of 8.2-5.5 Ma. The interbeds of turbidity currents deposits and mass transport deposits (MTDs) were developed in the period of 5.5-3.8 Ma (T30-T28). After then, the canyon fillings were primarily made up of large scale MTDs, interrupted by small scale turbidity channels and thin pelagic mudstones. The Central Canyon can be divided into three types according to the main controlling factors, geomorphology-controlled, fault-controlled and intrusion-modified canyons. Among them, the geomorphology-controlled canyon is developed at the Ledong, Lingshui, Songnan and western Baodao Depressions, situated in a confined basin center between the northern slope and the South Uplift Belt along the Central Depression Belt. The fault-controlled canyon is developed mainly along the deep-seated faults in the Changchang Depression and eastern Baodao Depression. Intrusion-modified canyon is only occurred in the Songnan Low Uplift, which is still mainly controlled by geomorphology, the intrusion just modified seabed morphology. The full-filled time of the Central Canyon differs from west to east, displaying a tendency of being successively late eastward. The geomorphology-controlled canyon was completely filled before 3.8 Ma (T28), but that in intrusion-modified canyon was delayed to 2.4 Ma (T27) because of the uplifted southern canyon wall. To the Changchang Depression, the complete filling time was successively late eastward, and the canyon in eastern Changchang Depression is still not fully filled up to today. Difference in full-filled time in the Central Canyon is mainly governed by multiple sediment supplies and regional tectonic activities. Due to sufficient supply of turbidity currents and MTDs from west and north respectively, western segment of the Central Canyon is entirely filled up earlier. Owing to slower sediment supply rate, together with differential subsidence by deep-seated faults, the full-filled time of the canyon is put off eastwards gradually.
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