A GIS-based Quantitative Prediction of Seafloor Massive Sulfide on Ultraslow-spreading Ridges: a Case Study of SWIR 48.7° E - 50.5° E

Abstract:

With the depletion of mineral resources on land, seafloor massive sulphide (SMS) deposits have the potential to become as important for exploration, development and mining as those mineral resources on land. However, it is difficult to investigate the ocean environment where SMS deposits are located; thus, improving prospecting efficiency by reducing the exploration search space using Mineral Potential Modelling is desirable. Mineral Potential Modelling has been used in the exploration of seafloor deposits, but there have been studies to aid exploration for SMS on ultraslow-spreading ridges using data related to geochemistry, substrate, and hydrothermal plume anomaly. Recent years，Chinese Dayang cruises have collected data that are applicable to prediction of SMS include: water depth, geology, sediment geochemistry, and hydrothermal plume anomaly on the Southwest Indian Ridge (SWIR) 48.7°E – 50.5°E. According to the prospecting criterions , we extract predictive maps from the collected data by spatially analysis. ,and map those factors that help predict the location of SMS deposits on this ridge. Subsequently, 15 predictive maps were used to establish a quantitative prediction model for SMS on this ultraslow-spreading ridge. Finally, based on the proposed model, the weights-of-evidence method was used to predict the location of SMS mineralization. The weight values from the spatial analysis indicated that the location of SMS deposits is best spatially correlated with e-type faults, detachment faults, oceanic crust thickness, and distance from the ridge axis. Areas with high posterior probability values correlate with known existing hydrothermal fields, providing confidence that the Mineral Potential Model for mapping the location of SMS deposits on this ultraslow-spreading ridge established in this paper is feasible. The predicted results are helpful for narrowing the exploration search space on this ridge and have implications for investigating and evaluating SMS resources elsewhere on ultraslow-spreading ridges.