| 潘大东,王张华,陈艇,高晓琴,李晓,战庆.长江口表层沉积物矿物磁性分区特征及其沉积环境指示意义[J].海洋学报,2015,37(5):101-111 |
| 长江口表层沉积物矿物磁性分区特征及其沉积环境指示意义 |
| Mineral magnetic characteristics of surficial sediments and their implications for identifying sedimentary environments at the Changjiang River mouth |
| 投稿时间：2014-10-27 修订日期：2014-12-24 |
| DOI：10.3969/j.issn.0253-4193.2015.05.010 |
| 中文关键词: 沉积动力 磁性参数组合 沉积相识别 长江口 |
| 英文关键词:hydrodynamic sorting magnetic parameters identification of sedimentary facies the Changjiang River mouth |
| 基金项目:国家自然科学基金项目(41176070);河口海岸学国家重点实验室科研业务费项目(SKLEC-2012KYYW01);国土资源部公益项目(201211009)。 |
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| 中文摘要: |
| 本研究旨在揭示现代长江口不同沉积环境铁磁性矿物的分布差异,寻找有效识别河口－陆架沉积环境的磁学指标,以便更好地将环境磁学应用于河口古环境研究。在长江口及邻近陆架的6个沉积环境:汊道、拦门沙、三角洲前缘斜坡、前三角洲、前三角洲－陆架过渡区和残留砂区,采集表层沉积物样品,进行粒度和磁性测量。结果显示,χ和SIRM在汊道和拦门沙呈现显著高值,HIRM、χfd%、χARM、χARM/χ和χARM/SIRM在前三角洲和前缘斜坡呈现显著高值,反映了陆源物质输运距离和河口沉积动力对磁性矿物分布的控制作用。因此,参数组合HIRM、χARM、χARM/χ和χARM/SIRM可用于识别全新世地层前缘斜坡和前三角洲－陆架;参数组合χ、SIRM和S-20mT可尝试用于识别汊道和拦门沙环境。 |
| 英文摘要: |
| This study attempted to reveal the distribution patterns of magnetic minerals in the various sedimentary environments of Changjiang River mouth and adjacent continental shelf,and assessed proxies of magnetic parameters for identifying sedimentary environments,and the obtained results would be used to better perform the paleo-environmental reconstruction. We collected surficial sediments from the following six sedimentary environments at the Changjiang River mouth and adjacent continental shelf: distributary channel,river mouth shoal,delta front slope,prodelta,transitional regions and relict sand,and measured their grain size and magnetic properties. The results showed that,significantly high χ and SIRM values were obtained for sediments from the distributary channel and river mouth shoal,and high values of HIRM,χfd%,χARM,χARM/χ and χARM/SIRM were measured for sediments from prodelta and delta front slope,indicating that the distribution of magnetic minerals was controlled by the dispersal of terrigenous sediments and hydrodynamic sorting. We proposed that for the Holocene stratigraphy,magnetic parameter assemblage of HIRM,χARM,χARM/χ and χARM/SIRM could be the effective indicator for identifying prodelta and delta front slope,and χ、SIRM and S-20mT can be used to recognize the distributary channel and river mouth shoal. |
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