SEDIMENT GEOCHEMISTRY FROM 13°N EAST PACIFIC RISE HYDROTHERMAL FIELD
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摘要: 对东太平洋海隆(EPR)13°N西侧2个沉积物岩心进行了碳酸盐、常量和微量元素测定。沉积物中Fe和Mn的含量较高,其中,E271站位沉积物岩心中Fe含量8.5%~13.8%,Mn含量1.7%~3.17%;E272站Fe含量6%~13%,Mn含量0.12%~3.31%,显示在EPR 13°N热液活动区西侧25~45 km处热液柱对沉积作用的影响明显。E271和E272站位CaCO3含量分别为5.9%~27.57%和6.67%~38.20%。热液柱的沉积作用,使Cu、Pb和Zn在沉积物中富集,Cu/Fe、Pb/Fe和Zn/Fe比值低于热液喷口处的颗粒物中值,Pb表现出在海水中运移距离较短或者只有少量Pb随热液柱扩散运移。热液柱在E271和E272站位的沉积作用使得Li、Mo和Ni在沉积物中富集,此外,V因为铁氧化物颗粒吸从海水中吸附并沉降到沉积物中。沉积物中Ti和Al有非常好的相关性,其Ti/Al比值为0.05左右,与太平洋深海沉积相比具有更高的铁含量,而U在岩心中的含量与深海沉积相似。Abstract: Element analyses have been carried out on the sediment cores from East Pacific Rise 13°N. Sediments are rich in Fe and Mn, with Fe contents from 8.5% to 13.8% in E271 and 6% to 13% in E272, Mn contents from 1.7% to 3.17% and from 6% to 13% respectively, which indicates important sedimentation influences of hydrothermal plume at a distance of 25~45 km west of EPR 13°N hydrothermal field. Carbonates also occupy an important component, with E271 from 5.9% to 27.57% and E272 from 6.67% to 38.20%. A few foraminifer fossils were found in the sediment cores. These sediments are rich in Cu, Pb and Zn which are fallout from hydrothermal plume with iron oxides. Cu/Fe, Pb/Fe and Zn/Fe ratios are lower than those in vent particles. Pb performs short transport distance or only minor Pb transports with iron oxides particles. Sediments are rich in Li, Mo and Ni as well. Further, plume supplies V to underlying sediment by scavenging from seawater. Ti and Al have a good correlation, with Ti/Al ratio nearly at 0.05. U content of the cores is similar to that of the pelagic sediments.
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Key words:
- hydrothermal plume /
- sediment /
- iron oxides /
- trace element /
- East Pacific Rise
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