Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
The Late Miocene Red River Submarine Fan in the Northwestern South China Sea: Characteristics and Exploration Significance
(1) College of Geosience, China University of Petroleum, Beijing, China.
(2) The Research Institute, CNOOC, Beijing, China.
(3) Department of Earth and Atmospheric Science, University of Houston, Houston, TX.
(4) School of Energy Resources, Chengdu University of Technology, Chengdu, China.
(5) School of Energy Resources, China University of Geosciences, Beijing, China.
Based on an integrated analysis of well log, core, and regional seismic data, a huge submarine fan is discovered at the boundary between the Yinggehai and the Qiongdongnan basins located in the northwestern South China Sea.
The fan, mainly formed during late Miocene (the Huangliu Period), is characterized by wedge-shaped oblique progradation configurations along depositional dip and bilaterial downlapping geometries along strike. Analysis of seismic data shows that the fan has an area over 10000 km2 and a maximum thickness of over 2000 m. Core and well log data from the YC35-1-2 well located in the distal side of the fan indicate that it mainly consists of sandy gravity-flow deposits in the lower part and interbedded sandstones and mudstones in the upper part. This, coupled with the fact that the study area during the Huangliu Period is bathyal, suggests that the fan is a sand-/mud-rich submarine fan with a sandy lower part up to 5000 km2.
Preliminary provenance analysis indicates that neither the Guiren Uplift to the west nor the Hainan Uplift to the north serves as the major source for the submarine fan. Facies analysis of the Huangliu Fromation in the Yinggehai basin, in fact, suggests that the Red River is the major feeding river for the growth of the submarine fan. The fan is, thus, named as the Red River submarine fan.
The integrated study shows that during late Middle Miocene a distinct shelf break was developed along and/or near the boundary between the Yinggehai and the Qiongdongnan basins under the affect of the Dongsha movement. Meanwhile, the tectonic event also leads to a large-scale relative sea-level fall in the Yinggehai Basin. The Red River system, in response, shifted dramatically basinward towards the boundary between these two basins, resulting in the quick growth of the submarine fan.
The discovery of the Red River submarine fan provides important information for the uplift of the Tibetan Plateau and the evolvement of Red River Fault Zone. It also points to a new direction for deepwater hydrocarbon exploration in the northern South China Sea.
Acknowledgements:This work was supported by the National Basic Research Program of China (No.2009CB219407) and the National Natural Science Foundation of China (No.40972077)