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东海内陆架沉积物磁性特征对早期成岩作用的响应
  • ISSN号:1001-7410
  • 期刊名称:《第四纪研究》
  • 时间:0
  • 分类:P318.41[天文地球—固体地球物理学;天文地球—地球物理学] P736[天文地球—海洋地质;天文地球—海洋科学]
  • 作者机构:[1]浙江师范大学地理与环境科学学院,金华321004, [2]华东师范大学河口海岸学国家重点实验室,上海200062
  • 相关基金:国家自然科学基金项目(批准号:40771201)、国家重点基础研究发展规划项目(973项目)(批准号:2010CB951204)和教育部新世纪优秀人才支持计划项目(批准号:NCET-08-0195)共同资助
中文摘要:

以东海内陆架泥质区F17柱样为对象,在放射性同位素测年、磁性测量、地球化学和粒度分析的基础上,探讨了早期成岩作用对陆架沉积物磁性特征的影响。结果表明,F17柱样磁性特征存在显著的垂向变化,表现为随深度的增加,沉积物磁性减弱、磁性颗粒变粗和不完整反铁磁性矿物比例上升。粒度以及Al,Ti,Fe,Mn的含量,有机碳和总硫的分析表明,沉积物物源相对均一,粒度虽然存在垂向变化,但不是磁性特征垂向变化的主要原因,早期成岩作用是导致上述磁性特征垂向变化的主要因素。早期成岩过程中,亚铁磁性矿物含量随深度下降的现象与其他地区报道的结果类似,但磁性矿物类型和颗粒大小随深度变化的模式,不同地区存在一定差异。基于磁性矿物对早期成岩过程的敏感性,磁性测量方法对认识铁在陆架沉积物中的迁移和转化具有积极作用。

英文摘要:

This paper discusses the influence of early diagenesis on magnetic properties of sediments from inner shelf of the East China Sea, using combined granulometric, magnetic and geochemical analyses. Sediment core F17 (26°40'N,120°30'E) ,271cm in length,was collected from a water depth of 41.4m using a gravity core sampler. The sediment core displays a yellowish brown color in the top 40cm layer,which gradually changes into grey color with depth. The sediments are dominated by clay silts. The core was sectioned at lcm intervals, dried at low temperature of 40℃. Except an aliquot for particle size analysis, the remaining parts were ground with mortar and pestle before magnetic and geochemical analyses. The sediment samples were analyzed for 210pb and 137Cs activities using HPGe Υ spectrometer(GWL-120210S) for establishing core chronology. Sedimentation rate for the top 50cm layer is averaged at 0.49cm/a,which is in accordance with reported sedimentation rates in the study area. Assuming such a sedimentation rate for the whole core,then the core is deposited in the last 550 years. Based on the result of radionuclide dating, magnetic measurements and particle size analysis were carried out at 2cm intervals, while geochemical analysis at 10cm intervals. The results indicate that the mean particle size of F17 ranges between 41μm and 12p, m,which increases with depth. Magnetic properties of core F17 display marked vertical variations, which can be divided into four zones, showing a general declining concentration of ferrimagnetic mineral and coarsening grain size with depth. In contrast, the proportion of antiferromagnetic minerals increases relatively with depth. Although particle size varies with depth,it plays a minor role in the change of magnetic properties. Both A1 and Ti show minor variations with depth,indicating that sediment provenance is relatively stable. Total sulfur (TS) content increases with depth. Organic carbon to TS ratio (C/S) and Mn/Fe, indicators of redox condition of sedimen

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期刊信息
  • 《第四纪研究》
  • 中国科技核心期刊
  • 主管单位:中国科学院
  • 主办单位:中国科学院地质与地球物理研究所 中国第四纪研究委员会
  • 主编:郭正堂
  • 地址:北京9825信箱
  • 邮编:100029
  • 邮箱:dsj@mail.igcas.ac.cn dsjs@mail.igcas.ac.cn
  • 电话:010-82998119
  • 国际标准刊号:ISSN:1001-7410
  • 国内统一刊号:ISSN:11-2708/P
  • 邮发代号:82-428
  • 获奖情况:
  • 1996年被国务院学位委员会地球物理及地质学科评议...,2001年入中国期刊方阵,2007年获中国科学院出版基金科技期刊排行榜三等奖
  • 国内外数据库收录:
  • 美国化学文摘(网络版),英国动物学记录,日本日本科学技术振兴机构数据库,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),中国北大核心期刊(2000版)
  • 被引量:17826