A preliminary study on sediment flux in the Changjiang Delta during the postglacial period  

作　　者：李保华 李从先 沈焕庭 

机构地区：[1]Key Laboratory of Marine Geology, Ministry of Education of China, Tongji University [2]State Key Laboratory of Estuarine and Coastal Research, East China Normal University

出　　处：《Science China Earth Sciences》2003年第7期743-752,共10页中国科学（地球科学英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.49976016 , 49736220).

摘　　要：The sequence boundary and maximum flooding surface of the postglacial transgressive cycle in the Changjiang Delta have been identified by 265 cores. Based on these data, the sediment amounts and the thickness-isopach maps of postglacial sedimentary cycle, transgressive and regressive successions in the Changjiang Delta have been worked out. The results show that the sediment amounts of the postglacial cycle, transgressive succession and regressive succession are 17742.2×108 tons, 9791.9×108 tons and 7950.3×108 tons, respectively. The postglacial sediments deposited in the incised valley are more than those in the two flanks, and the sediments contained in the transgressive succession are more than those in the regressive succession. The postglacial sediments deposited in the southern flank are more than those in the northern flank, and the sediments in the area seaward from the postglacial transgression maximum (PTM) of each flank are more than those in the area landward from the PTM. Considering both the possible changes of the ratio between the sediment amount remained in the modern Changjiang Delta and the sediment discharge of the Changjiang River in the postglacial period, and the changes of the sediment discharge, the authors believe that in the postglacial period, the sediment discharge of the Changjiang River is (2.36—4.86)×108 tons/a on average, totaling to (35400—70800)×108 tons, and the sediments delivered to sea and adjacent coasts are (1.18—3.54)×108 tons/a on average, totaling to (17700—53100)×108 tons.The sequence boundary and maximum flooding surface of the postglacial transgressive cycle in the Changjiang Delta have been identified by 265 cores. Based on these data, the sediment amounts and the thickness-isopach maps of postglacial sedimentary cycle, transgressive and regressive successions in the Changjiang Delta have been worked out. The results show that the sediment amounts of the postglacial cycle, transgressive succession and regressive succession are 17742.2 × 108 tons, 9791.9 × 108 tons and 7950.3 × 108 tons, respectively. The postglacial sediments deposited in the incised valley are more than those in the two flanks, and the sediments contained in the transgressive succession are more than those in the regressive succession. The postglacial sediments deposited in the southern flank are more than those in the northern flank, and the sediments in the area seaward from the postglacial transgression maximum (PTM) of each flank are more than those in the area landward from the PTM. Considering both the possible changes of the ratio between the sediment amount remained in the modern Changjiang Delta and the sediment discharge of the Changjiang River in the postglacial period, and the changes of the sediment discharge, the authors believe that in the postglacial period, the sediment discharge of the Changjiang River is (2.36–4.86) × 108 tons/a on average, totaling to (35400–70800) × 108 tons, and the sediments delivered to sea and adjacent coasts are (1.18–3.54) × 108 tons/a on average, totaling to (17700–53100) × 108 tons.

关 键 词：postglacial transgressive cylce  the CHANGJIANG River  the CHANGJIANG Delta  SEDIMENT flux  transgressive succession  REGRESSIVE succession. 

分 类 号：P731[天文地球—海洋科学]