AMS14C dating and analysis of grain size,major elements and clay minerals were applied to Core MZ01 from the mud area on the inner shelf of the East China Sea.Based on the environmentally sensitive grain size,clay min...AMS14C dating and analysis of grain size,major elements and clay minerals were applied to Core MZ01 from the mud area on the inner shelf of the East China Sea.Based on the environmentally sensitive grain size,clay mineral and major element assemblages,the history of the East Asia winter monsoon since the mid-Holocene could be reconstructed.These three proxies,mean grain size(>9.71μm),chemical index of alteration(CIA)and ratio of smectite to kaolinite in particular,show similar fluctuation patterns. Furthermore,10 extreme values corresponding to the contemporary cooling events could be recognized since the mid-Holocene;these extreme values are likely to have been caused by the strengthening of the East Asia winter monsoon.The cooling events correlated well with the results of theδ18O curves of the Dunde ice core and GISP2,which therefore revealed a regional response to global climate change.Four stages of the East Asia winter monsoon were identified,i.e.8300-6300 a BP,strong and unstable;6300-3800 a BP,strong but stable;3800-1400 a BP,weak and unstable;after 1400 a BP,weak but stable.展开更多
Gravity core EC2005, located in the mud wedge off the Zhejiang-Fujian coast in the inner shelf of the East China Sea （ECS）, was analyzed for its lithology, grain size, rare earth elements （REE） and AMS14C dating. ...Gravity core EC2005, located in the mud wedge off the Zhejiang-Fujian coast in the inner shelf of the East China Sea （ECS）, was analyzed for its lithology, grain size, rare earth elements （REE） and AMS14C dating. Results revealed high-resolution paleoenvironmental evolution and multiple switches of sediment provenances in the inner shelf of ECS. The lithology, grain size and REE concentrations of sediments varied significantly down the core. Mean grain size ranged from 8 to 121 μm, and the values of ΣREE were 152.8-227.9 μg/g. The chondrite- and shale-normalized REE patterns indicated their similarity to the terrigenous sediments in the study area. Between 17.3-12.3 ka BP the sediments in the inner shelf of ECS were mainly originated from local drainage basins. The source then gradually switched to the Yangtze River between 12.3 and 9.8 ka BP. Since about 10-9.8 ka BP, the sediments in the study area were dominantly derived from the Yangtze River. The continuous rising of sea level and formation of coastal current along the inner shelf played a key role in the switches of sediment provenances.展开更多
通过对位于东海内陆架泥质区中部的MZ02柱样岩芯进行粒度、常量元素、AMS14C分析,获得了粒度和常量元素随时间变化的高分辨率曲线。结果表明,近2 ka以来研究区沉积环境稳定,以沿岸流控制的浅海沉积为主,沉积物中CaO/K2O,MgO/Al2O3和MnO/...通过对位于东海内陆架泥质区中部的MZ02柱样岩芯进行粒度、常量元素、AMS14C分析,获得了粒度和常量元素随时间变化的高分辨率曲线。结果表明,近2 ka以来研究区沉积环境稳定,以沿岸流控制的浅海沉积为主,沉积物中CaO/K2O,MgO/Al2O3和MnO/Na2O比值的变化与我国东部气候变化序列具有较好的一致性,证明这些元素地球化学指标可以作为古气候变化的高分辨率替代性指标。近2 ka以来CaO/K2O、MgO/Al2O3和MnO/Na2O共同识别出的7次极值揭示了同期的降温事件,分别发生在～1 480 a BP(C1),～1 200 a BP(C2),～1 020 a BP(C3),～780 a BP(C4),～580 a BP(C5),～330 a BP(C6),～120 a BP(C7),且在其他区域不同介质中也能找到相应的降温证据,揭示了气候变化的区域性以至全球性联系。展开更多
基金supported by the Coastal Investigation and Research Project of China(908-ZC-I-05 and 908-02-02-05)the Marine Public Welfare Research Project(200805063)the Key Program of the National Natural Science Foundation of China(40431002)
文摘AMS14C dating and analysis of grain size,major elements and clay minerals were applied to Core MZ01 from the mud area on the inner shelf of the East China Sea.Based on the environmentally sensitive grain size,clay mineral and major element assemblages,the history of the East Asia winter monsoon since the mid-Holocene could be reconstructed.These three proxies,mean grain size(>9.71μm),chemical index of alteration(CIA)and ratio of smectite to kaolinite in particular,show similar fluctuation patterns. Furthermore,10 extreme values corresponding to the contemporary cooling events could be recognized since the mid-Holocene;these extreme values are likely to have been caused by the strengthening of the East Asia winter monsoon.The cooling events correlated well with the results of theδ18O curves of the Dunde ice core and GISP2,which therefore revealed a regional response to global climate change.Four stages of the East Asia winter monsoon were identified,i.e.8300-6300 a BP,strong and unstable;6300-3800 a BP,strong but stable;3800-1400 a BP,weak and unstable;after 1400 a BP,weak but stable.
基金supported by the National Natural Science Foundation of China (40776030)Natural Science Foundation of Shandong Province (ZR2010DL009)+2 种基金Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences (MGE2010KG02)Fundamental Research Funds for the Central Universities (10CX04004A)the Doctoral Fund of China University of Petroleum (Y0901036)
文摘Gravity core EC2005, located in the mud wedge off the Zhejiang-Fujian coast in the inner shelf of the East China Sea （ECS）, was analyzed for its lithology, grain size, rare earth elements （REE） and AMS14C dating. Results revealed high-resolution paleoenvironmental evolution and multiple switches of sediment provenances in the inner shelf of ECS. The lithology, grain size and REE concentrations of sediments varied significantly down the core. Mean grain size ranged from 8 to 121 μm, and the values of ΣREE were 152.8-227.9 μg/g. The chondrite- and shale-normalized REE patterns indicated their similarity to the terrigenous sediments in the study area. Between 17.3-12.3 ka BP the sediments in the inner shelf of ECS were mainly originated from local drainage basins. The source then gradually switched to the Yangtze River between 12.3 and 9.8 ka BP. Since about 10-9.8 ka BP, the sediments in the study area were dominantly derived from the Yangtze River. The continuous rising of sea level and formation of coastal current along the inner shelf played a key role in the switches of sediment provenances.
文摘通过对位于东海内陆架泥质区中部的MZ02柱样岩芯进行粒度、常量元素、AMS14C分析,获得了粒度和常量元素随时间变化的高分辨率曲线。结果表明,近2 ka以来研究区沉积环境稳定,以沿岸流控制的浅海沉积为主,沉积物中CaO/K2O,MgO/Al2O3和MnO/Na2O比值的变化与我国东部气候变化序列具有较好的一致性,证明这些元素地球化学指标可以作为古气候变化的高分辨率替代性指标。近2 ka以来CaO/K2O、MgO/Al2O3和MnO/Na2O共同识别出的7次极值揭示了同期的降温事件,分别发生在～1 480 a BP(C1),～1 200 a BP(C2),～1 020 a BP(C3),～780 a BP(C4),～580 a BP(C5),～330 a BP(C6),～120 a BP(C7),且在其他区域不同介质中也能找到相应的降温证据,揭示了气候变化的区域性以至全球性联系。
