Geochemical Characteristics and Formation Mechanism of Sediments from the Challenger Deep in the Southern Mariana Trench
[Objective]To investigate the hadal sediments main type,geochemical characteristics and formation in the Challenger Deep of the southern Mariana Trench,[Methods]the mineralogical and geochemical analysis were uesd to study the sediments and altered basalt from north slope(overlying plate)and axis to the south slope(subduc-tion plate)at the Challenger Deep of the Mariana Trench.[Results and Conclusions]The hadal sediments can be divided into four types:red deep-sea clay,siliceous sediments,micromanganese-rich sediments,and calcareous sediments.The red deep-sea clay is the most common type of hadal sediment,which contribute the most to subducted sediments.Major and trace element geochemical characteristics are similar to those of altered basalt of the oceanic crust,which imply that red clay is mainly derived from the basalt alteration of the subducted and overlying plates,rather than the volcanic and terrestrial inputs.Moreover,intensified organic matter diagenesis has an important in-fluence on the geochemical properties of the hadal sediments,which is the main reason the Challenger Deep sedi-ments have lower rare earth elements and enrich more micromanganese nodules than the adjacent deep-sea sediments.
国家科技期刊平台
NSTL
万方数据
