TROPICAL GEOGRAPHY ›› 2016, Vol. 36 ›› Issue (3): 334-342.doi: 10.13284/j.cnki.rddl.002850

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Late Quaternary Tectonic Movements in the Pearl River Delta, China, Revealed from Stratigraphic Profiles

YU Zhangxin,ZHANG Ke,LIANG Hao,LI Zhongyun   

  1. (School of Earth Science and Geological Engineering,Sun Yat-Sen University,Guangzhou 510275,China)
  • Online:2016-05-05 Published:2016-05-05

Abstract: The Pearl River Delta is located at north margin of the South China Sea. Neotectonic movements play important role on the evolution of the delta featured as fault-blocks differential uplift and subsidence. Some critical topics, e.g. the active variation of different fault groups, the pattern of fault-blocks movements, are still debatable. Recently some Quaternary depositional terraces were discovered on Panyu Platform in the north Pearl River Delta. Those terraces can be identified into several stratigraphic layers: A. migmatite or granite bedrocks which have been deeply weathered into vermicular red soil, B. greyish white and yellow medium/coarse sand, cross-bedding structure, with weathering surfaces, C. dark grey to black silt with a few fine sand lense, wood fragments layer in the bottom, and D. dark grey silt, rhythmically intercalated by greyish white sand layers. Study on sedimentary facies of those layers shows that this sequence belongs to the Pearl River Delta lower marine transgressive cycle, which means the delta deposits was tilted after the 1st transgressive deposition, due to the NNW trending Hualong-Huangge fault zone. Other W-E and N-S trending terrace-borehole stratigraphic profiles in the Pearl River Delta area reveal the active variation of different fault groups. The W-E and NE-SW trending faults control the edge of the Pearl River Delta, while little influence on the pattern of delta deposition process and river channel distribution. The NNW-SSE and NEE-SWW trending faults are still active since the 1st marine transgression, making the delta deposits weekly tilt. The comparison of sedimentary sequence in the Pearl River Delta with continental shelf of the Northern South China Sea illustrates that besides the 2 cycles in the Pearl River Delta, there are much older cycles on the continental shelf due to intensive activities of the Littoral Fault Zone.

Key words: neotectonics, Quaternary depositional terrace, active fault, the Pearl River Delta