Research On The Co-rich Ferromanganese Crusts And Paleoceanic Environments Of The Western Pacific Seamounts

Tectonic and ocean flow activities are very active in the low latitude western Pacific, whichmakes the local enrichment of the Co-rich polymetallic crusts high in this area. The broaddistribution of the seamounts and volcanic clusters of hot spot type provide the prerequisite ofoccurrence and enrichment of Co-rich ferromanganese crusts. Magellan seamount is a importantresearch area of the Co-rich ferromanganese crusts in our country. Through net dragging, gravitysampling, multi-wave depth measuring, marine physical and chemistry characteristics measuringand seafloor photograph, we get a great deal of crusts and base rock samples and many real timedata, which form a strong basis for the incorporation of the related research..Through the comparison between the petrology, geochemistry and the age dating data of thesamples of our key research area and those of the ocean probing incorporated in the area that sharethe same tectonic unit, mass source and physical and chemistry conditions with Magellanseamount and has experienced the similar evolution history, individual, disordered materialsbecome integrated and ordered, and the materials in some area has been expanded.Research of the paleoceanic environment formed in the top layer of sediments was carried bythe tests of carbonate salts, δ13C isotope, organic C and the comparison of the data..In order to make sure the age of the ferromanganese crusts, research on micro fossils andelementary chemistry is incorporated. Combined with the simultaneous paleoceanic events, thepaleoceanic environment where the ferromanganese crusts developed was conjectured. What kindof role each element plays in the formation of the crusts can be confirmed through thecomprehensive analysis of both the crusts' age and elementary content.The test of the samples' chemistry composition indicates that there is a positive correlationbetween the elements of Mn and Co, while there is a negative correlation between those of Cu andCo. Combined with the occurrence position, the growth rate of the crusts shows that the two crustsamples developed in the same period.The beginning of the development of the crusts is about 59 Ma through the experienceformula and the micro fossil research. This age is between the crusts of 876 and 873 stations.During the early days of the occurrence of the crusts, elements from the base rocks takeactive part in the formation of the crusts. The component of elements of Co, Cu, Mn, Fe, Znincreased dramatically. During the stage after this period, in the middle loosen layer, component ofCo, Mn, and Fe continue to increase slowly, while the component of Cu and Zn decrease.