Holocene depocenter shift in the middle-lower Changjiang River basins and coastal area in response to sea level change |
| |
| Authors: | Zhanghua WANG Jingpu LIU Baocheng ZHAO |
| |
| Institution: | (1) State Key Laboratory of Estuarine and Coastal Science, East China Normal University, Shanghai, 200062, China |
| |
| Abstract: | Authors collected 38 sedimentary boreholes and numerous seismic profiles from previous publications to delineate the Holocene
sedimentation rate of six major depositional sinks in the middle-lower Changjiang River basins and its river coast. The results
demonstrate that the highest sedimentation rate of ca. 15 m/ka occurred in the mono-depositional sink of the former Changjiang
River mouth during 10 000–8000 aBP, when post-glacial transgression happened and the Changjiang water level remained at lower
stand. With the rising of the Changjiang water level in response to sea level rise, Jianghan Basin of the middle Changjiang
River becomes the other important depositional sink with highest sedimentation rate of 10 m/ka since 7000 aBP. As Jianghan
Basin was mostly filled up at ca. 4000 aBP, Dongting Basin and the lower Changjiang valley trapped sediments in great amounts
like in the river mouth. A considerable amount of Changjiang sediments has been delivered, both eastward and southward, to
the inner continental shelf of the East China Sea, especially after 2000 aBP. This indicates reduced sediment storage capacity
of the middle-lower Changjiang valley and the river mouth. In total, ca. 1307.4 billion tons of sediment have deposited in
the middle-lower Changjiang floodplain since 7000 aBP. In the meantime, ca. 947 billion tons of sediment have been deposited
in the river coast to form the Changjiang subaqueous delta and the Zhejiang-Fujian along-shelf mud wedge. Our result also
reveals two time stages with lower sedimentation rates(< 4 m/ka) in all basins during 8000–7000 aBP and in the estuarine area
during 4000–2000 aBP, probably owing to stengthened chemical weathering of decline of monsoon precipitation.
__________
Translated from Journal of Palaeogeography, 2007, 9(4):419–429 译自: 古地理学报] |
| |
| Keywords: | sedimentation rate depositional sink sediment storage capacity |
| 本文献已被 万方数据 SpringerLink 等数据库收录！ |
|
