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末次冰消期以来东海内陆架沉积物磁化率的环境意义
The paleoenvironmental significance of magnetic susceptibility of sediments on the East China Sea inner shelf since the last deglaciation
投稿时间:2010-02-22  修订日期:2010-12-21
DOI:
中文关键词:  东海内陆架  末次冰消期  磁化率  沉积环境  成岩作用
英文关键词:inner shelf of the East China Sea  last deglaciation  magnetic susceptibility  sedimentary environment  diagenesis
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
作者单位E-mail
徐方建 中国石油大学(华东) 地球资源与信息学院 xufangjiangg@163.com 
李安春 中国科学院海洋研究所 海洋地质与环境重点实验室  
李铁刚 中国科学院海洋研究所 海洋地质与环境重点实验室  
陈世悦 中国石油大学(华东) 地球资源与信息学院  
操应长 中国石油大学(华东) 地球资源与信息学院  
董春梅 中国石油大学(华东) 地球资源与信息学院  
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中文摘要:
      对末次冰消期以来东海内陆架沉积物磁化率的影响因素及其蕴含的古环境信息进行了探讨。对位于浙闽沿岸泥质沉积中心附近的EC2005孔磁化率、岩性、粒度、常量元素、矿物以及AMS14C测年数据进行了综合分析,得出以下主要结论:EC2005孔磁化率数据的变化受到多种因素的制约,不同层位的主要控制因素不同,60.20~28.06 m主要受到岩性控制,28.06~8.40 m主要受到早期成岩还原作用的影响,8.40 m以上层位可能主要受到人类活动的影响。岩心底部60.20~41.00 m磁化率的逐渐降低对应了气候暖湿化、湖泊逐渐扩张的过程,这与以往磁化率高值对应于暖湿气候条件的观点不符,说明由于研究区不同,其蕴含的信息也会有所不同。对不同研究区磁化率作为气候代用指标进行应用时要慎重,应该对其指示意义进行深入探讨。
英文摘要:
      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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