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Centurial Cycles of Variation of the Holocene East Asian Monsoon |
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Abstract: AMS14C dating and grain-size analysis for Core PC-6, located in the middle of a mud area on the inner shelf of the East China Sea (ECS), were used to rebuild the Holocene history of the East Asian winter monsoon (EAWM). The 7.5-m core recorded the history of environmental changes during the postglacial transgression. The core was divided into three sections with boundaries at 450 cm and 540 cm, according to its lithology, color, sedimentary structure, and vertical stacking pattern of its sediment. The core's mud section (the upper 450 cm) has been formed mainly by suspended sediment delivered from the Yangtze River mouth by the ECS Winter Coastal Current (ECSWCC) since 7.6 kyr BP. Using a mathematical method called "grain size vs. standard deviation", we can divide the Core PC-6's grain-size distribution into two populations at about 28 μm. The fine population (<28 μm) is considered to be transported by the ECSWCC as suspended loads. Content of the fine population changes little and represents a stable sedimentary environment in accord with the present situation. Thus, variation of mean grain-size from the fine population would reflect the strength of ECSWCC, which is mainly controlled by the EAWM. Spectral analyses of the mean grain-size time series of Core PC-6 show statistically significant centurial periodicities centering on 70-72, 78, 89, 102, 112, 123, 154 years. The EAWM and the East Asian summer monsoon (EASM) agree with each other well on these cycles, and the East Asian Monsoon (EAM) and the Indian Monsoon also share in concurrent cycles in Holocene, which are in accord with the changes of sun irradiance.
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Received: 05 May 2009
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[1] |
WANG Hailei, ZHENG Mianping. Lake Level Changes Indicated by Grain-size of Core SL-1 Sediments Since 5.33 ka BP in Selin Co, Central Qinghai-Tibetan Plateau[J]. Science & Technology Review, 2014, 32(35): 29-34. |
[2] |
JIANG Jincheng;GUO Jiateng;WU Lixin;ZHANG Rongbing;YANG Yizhou. Multi-granularity Rasterization and Boolean Operation Parallel Algorithm for 3D Spatial Entities[J]. , 2011, 29(35): 18-23. |
[3] |
. Purification of Liquid Phase Silicon Dioxide from Reclaiming Tail Gas of Solar Polysilicon Production[J]. , 2010, 28(23): 104-107. |
[4] |
. Geochemical Studies on Rb and Sr in the Mud on the Inner Shelf of the East China Sea and Their Palaeoclimate Significance[J]. , 2007, 25(0703): 22-27. |
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