Abstract:
Ultra-slow spreading mid-ocean ridges have the potential to form large seafloor polymetallic sulphides, in which hydrothermal zones controlled by detachment faults are often characterized by large-scale, Cu-rich and Au-rich zones. Baishen Seamount is located at the inner corner of the Gallieni Transform Fault on the ultra-slow spreading southwest Indian Ridge, and the development of the detachment fault structure has favorable tectonic conditions for hydrothermal activity, but it has not been determined whether there is any hydrothermal activity in this area. In this paper, primary trace and rare earth elements and
in situ microzonation geochemical analyses were carried out on the surface sediments at four stations in the area, and results show that the sediments in the study area are rich in ultramafic clasts and may have been probably influenced by the basaltic breccias. Foraminiferal shells in the sediments are enriched in hydrothermal elements such as Fe and Mn, indicating that the study area was influenced by hydrothermal components. Based on the spatial distribution of enrichment features, it can be inferred that the probable location of the hydrothermally active vents is close to station A3 in the study area. This comprehensive analysis deepens the understanding of sediment source of this seamount and provides strong clues for hydrothermal identification or mineral searching in the ultra-slow mid-ocean ridge.