Flux and fate of Yangtze River sediment.pdf

2007) 208–224 /locate/geomorphGeomorphology 85 (Flux and fate of Yangtze River sediment delivered to the East China Sea J.P. Liu a,?, K.H. Xu b, A.C. Li c, J.D. Milliman b, D.M. Velozzi a, S.B. Xiao d, Z.S. Yang e a Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC, 27695, USA b School of Marine Science, College of William and Mary, Gloucester Pt. VA 23062, USA c Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China d South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China e College of Geo-Mari ne Sciences, Ocean University of China, Qingdao 266003, China Received 2 February 2005; received in revised form 22 April 2005; accepted 29 March 2006 Available online 8 September 2006Abstract Numerous cores and dating show the Yangtze River has accumulated about 1.16×1012 t sediment in its delta plain and proximal subaqueous delta during Holocene. High-resolution seismic profiling and coring in the southern East China Sea during 2003 and 2004 cruises has revealed an elongated (～800 km) distal subaqueous mud wedge extending from the Yangtze River mouth southward off the Zhejiang and Fujian coasts into the Taiwan Strait. Overlying what appears to be a transgressive sand layer, this distal clinoform thins offshore, from ～40 m thickness between the 20 and 30 m water depth to b1–2 m between 60 and 90 m water depth, corresponding to an across shelf distance of less than 100 km. Total volume of this distal mud wedge is about 4.5×1011 m3, equivalent to ～5.4×1011 t of sediment. Most of the sediment in this mud wedge comes from the Yangtze River, with some input presumably coming from local smaller rivers. Thus, the total Yangtze-derived sediments accumulated in its deltaic system and East China Sea inner shelf have amounted to about 1.7×1012 t. Preliminary analyses suggest this longshore and across-shelf transported clinoform mainly formed in the past 7000 yrs after postglac