Global seafloor massive sulfide prospective regions

A global shapefile delineating prospectivity regions for seafloor massive sulfides (SMS), also known as polymetallic sulfides, was developed to identify seabed regions permissive for hydrothermal sulfide mineralization. The dataset classifies regions according to their relative prospectivity for SMS mineralization using geological and oceanographic parameters, including evidence of hydrothermal activity. Prospective regions were classified into two categories: (1) Evidenced Polymetallic Sulfides, and (2) Permissive Polymetallic Sulfides. Evidenced regions contain documented occurrences of submarine hydrothermal sulfide mineralization, including conventional SMS deposits and the brine-hosted metalliferous sediments of the Red Sea (Atlantis II Deep). Permissive regions represent areas where geologic and oceanographic conditions are favorable for SMS formation, but where direct evidence is limited or absent.

The prospective regions were constructed in a geographic information system (GIS) using a synthesis of published and publicly available datasets. Divergent plate boundaries, such as mid-ocean ridges and back-arc spreading centers, where hydrothermal venting can occur, were delineated using global plate boundary models (Bird, 2003; Hasterok and others, 2022). A 100-kilometer buffer was applied to ridge-axis centerlines to produce permissive polygons with a total width of 200 kilometers, representing areas where geologic conditions are favorable for SMS formation but direct evidence is limited or absent; extinct spreading centers were excluded. Evidenced regions were delineated using documented occurrences of submarine hydrothermal activity compiled primarily from the InterRidge Global Database of Active Submarine Hydrothermal Vent Fields (Beaulieu and Szafranski, 2020). Vent fields were screened to retain only those in tectonic settings known to host SMS deposits (mid-ocean ridges, back-arc basins, and arc volcano systems), with depth constraints applied by setting to reflect conditions favorable for sulfide precipitation and preservation. Confirmed vent locations were grouped into regional clusters based on inter-point distance and converted to polygon geometries, which were reviewed and manually edited to improve boundary continuity and better reflect regional tectonic and bathymetric constraints. Additional datasets informed the classification, including observations of hydrothermal plume activity inferred from water column anomalies (for example, temperature, turbidity, redox-sensitive chemical tracers); bathymetric data to constrain depth ranges permissive for sulfide precipitation and preservation; and tectonic setting information, including spreading rate, ridge segmentation, and volcanic arc proximity.
The data provides a global-scale spatial framework for assessing SMS prospectivity, however an area designated here as prospective does not indicate whether minerals have been found in these regions, nor do they indicate the presence of a mineral deposit, or if one has been found, that it is economically viable.