Geochemistry of Molybdenum Element in Co-rich Crusts from the Magellan Seamounts and Tracing of Paleoceanographic Environment

摘要

In order to explore the geochemical characteristics of Mo elementrnin Cobalt-rich crusts and their relationship withrnpaleoceanographic environment variation, 56 crust samples and arnthick crust from 7 seamounts in the Magellan Seamounts (MST)rnhave been approached in detail. Studies show that the averagernMo content of crusts in the area is 444ppm; Mo exhibits arnpositive correlation with Mn, Ni and Ba with a correlationrncoefficient of 0.83, 0.79 and 0.52, respectively; a negativerncorrelation with Si, Al and Fe with a correlation coefficient ofrn-0.86, -0.74 and -0.64, respectively. Factor analysis shows thatrnMo in the MST Cobalt-rich crusts has a close relation withrnhydrogenous sedimentation and a definite relation withrnbiogeochemical process, but no relation with detritus and Fernphase. Based on the Co chronometer dating, we carry out thernresearch on the relation between Mo content variation andrnpaleoclimate, paleoceanographic phosphogenic events,rnpaleoceanographic redox environment during the growth processrnof a thick crust. The preliminary results reveal that Mo contentrnwould decrease with the climate getting cold; paleoceanographicrnphosphogenic events cause the loss of Mo content; the change ofrnpaleoceanographic redox environment exerts no influence on thernvariation of Mo content, and Mo dominant species of thernincorporation into Cobalt-rich crusts would be relatively simple.