Geochemical features of the hydrothermal sulfide on the Southern Mid-Atlantic Ridge near 15°S

With a systematic study on mineralogy of the three stations’ sulfide samples dredged from the seafloor hydrothermal field near 15°S Southern Mid-Atlantic Ridge, geochemical features of these sulfides are also described in detail. Bulk chemical analyses of sulfide samples were obtained using X-ray Fluorescence (XRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The sulfides on the Southern Mid-Atlantic Ridge (SMAR) near 15°S can be divided into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and enrich Fe, Zn and Cu concentrations successively. These sulfide precipitates are characterized by higher Zn and lower Cu concentrations relative to those found in other well-known hydrothermal fields along the Mid-Atlantic Ridge(MAR). Huge changes are obvious both its content and the associated eigenvalue of major elements, trace elements and rare earth elements (up to 10 times and even one hundred times in magnitude), which show that the sulfide formed in different hydrothermal mineralization stage. From low-temperature mineral assemblages to high-temperature mineral assemblages, the spatial distributions of dispersive and rare elements in the hydrothermal sulfide displayed corresponding variations.