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    The paleoenvironmental significance of magnetic susceptibility of sediments on the East China Sea inner shelf since the last deglaciation
    投稿時間:2010-02-22  修訂日期:2010-12-21
    中文關鍵詞:  東海內陸架  末次冰消期  磁化率  沉積環境  成巖作用
    英文關鍵詞:inner shelf of the East China Sea  last deglaciation  magnetic susceptibility  sedimentary environment  diagenesis
    徐方建 中國石油大學(華東) 地球資源與信息學院 266555
    李安春 中國科學院海洋研究所 海洋地質與環境重點實驗室 
    李鐵剛 中國科學院海洋研究所 海洋地質與環境重點實驗室 
    陳世悅 中國石油大學(華東) 地球資源與信息學院 
    操應長 中國石油大學(華東) 地球資源與信息學院 
    董春梅 中國石油大學(華東) 地球資源與信息學院 
    摘要點擊次數: 4557
    全文下載次數: 398
          對末次冰消期以來東海內陸架沉積物磁化率的影響因素及其蘊含的古環境信息進行了探討。對位于浙閩沿岸泥質沉積中心附近的EC2005孔磁化率、巖性、粒度、常量元素、礦物以及AMS14C測年數據進行了綜合分析,得出以下主要結論:EC2005孔磁化率數據的變化受到多種因素的制約,不同層位的主要控制因素不同,60.20~28.06 m主要受到巖性控制,28.06~8.40 m主要受到早期成巖還原作用的影響,8.40 m以上層位可能主要受到人類活動的影響。巖心底部60.20~41.00 m磁化率的逐漸降低對應了氣候暖濕化、湖泊逐漸擴張的過程,這與以往磁化率高值對應于暖濕氣候條件的觀點不符,說明由于研究區不同,其蘊含的信息也會有所不同。對不同研究區磁化率作為氣候代用指標進行應用時要慎重,應該對其指示意義進行深入探討。
          The paleoenvironmental significance of magnetic susceptibility (MS) and its effect factors in the sediments on the inner shelf of the East China Sea since the last deglaciation were discussed in this paper. On the basis of analysis on MS, lithology, grain-size, major elements, minerals and AMS14C dating of Core EC2005 which is located in the mud depocenter near the Zhejiang-Fujian coast, main conclusions are summarized as follows. The variations of MS were affected by many factors and the main effect factors at different layers changed significantly. The MS in core depth 60.20~28.06 m is controlled primarily by lithology, the variations in core depth 28.06~8.40 m are due to the impact of early diagenetic effects on magnetic minerals, and the MS above 8.40 m is likely to be affected by human activities. The decreasing MS at the bottom of 60.20~41.00 m is corresponding to the climate warming and wetting trend, lake expansion that occurred during this period. This view is inconsistent with the previous studies that the high MS value corresponds to the warm and humid climate conditions. It indicates climatic significance differs in different study areas. Therefore, caution must be exercised when MS was adopted as climate proxies. Its significance should be discussed in detail.
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