Analysis On The Regional Geological Background And Ore-controlling Factors Of Submarine Hydrothermal Sulfide

Submarine hydrothermal activity is one of the most important discoveries inthe field of marine science in the20th century, the study of modern submarinehydrothermal activity and the effect of the resources and the environment has become hotspot of earth science research nowadays. Submarine hydrothermal polymetallic sulfidesalso become the seabed deposits that receive the international concern. May2010,approved by the council of International Seabed Authority, China has obtained10thousand square kilometres seabed mining areas of exclusive exploration and prioritymining rights in the Southwest Indian Ocean. In order to understand submarinepolymetallic sulfide deposits comprehensively, and exploit these potential resources, wemust know firstly the distribution of hydrothermal activity, the regional geologicalenvironment, and its effect of size, metallogenic mechanism and other aspects ofhydrothermal polymetallic sulfides.On the basis of the latest data of global hydrothermal vent sites (588sites),extensive existing survey research results at home and abroad, as well as a large numberof documents are collected, all the collected data are picked up, rearranged and somefigures are drawn. Based on a comprehensively study of the bathymetry, gravity,magnetic, seismic and other data, the correlation between the distribution of globalsubmarine polymetallic sulfide deposits and plate tectonic positions are analysed, thecharacters of typical hydrothermal sulfide mining areas, such as geophysical field,basement rocks, sediment caps, lithosphere structure and so on, are discussed, the maincontrolling factors that constraint the formation and distribution of the submarinepolymetallic sulfides are extracted.The results show that submarine hydrothermal polymetallic sulfide vent sites mainly locate at divergent and convergent plate boundary. The plate tectonic positions can beclassified as four tectonic setting: mid-ocean ridge tectonic setting, back-arc basintectonic setting in the subducting plate edge of ocean-arc, continental margin tectonicsetting in the subducting plate edge of ocean-continent, intraplate hot spots tectonicsetting. The formation of submarine hydrothermal polymetallic sulfides is primarilycontrolled by deep magmatic activity, faults structure, sediment cap, spreading rate,water depth, the types of wall rock and other factors. Deep magmatic activity provideheat resource and mineral elements for the mineralization of the polymetallic sulfides,faults structure provide important guiding channels and fissures for hydrothermalactivity.Deep magmatic activity, submarine fault structure and the thickness of sediment inthe tectonic settings with different spreading rates are different. Deep magmatic activityand fault structure are the two most crucial controlling factors of submarine hydrothermalsystems and the mineralization of polymetallic sulfide. Different fault structure and deepmagmatic activity in fast-and slow-spreading tectonic settings contribute to different sizeof polymetallic sulfide deposits. Fast spreading tectonic settings with high magmaticbudgets, have continual diking events and small-scale fault structure. That results indispersive ejection of hydrothermal activity, small and short-lived hydrothermal vent, andsmall size of polymetallic sulfide deposits. Slow spreading tectonic settings with lowmagmatic budgets, have stable magmatic activity and large-scale fault structure. Thatcontributes to concentrated ejection of hydrothermal activity, large and longevity ofhydrothermal vents, and massive polymetallic sulfide deposits.