Potential mineral resources of the Atlantic Exclusive Economic Zone (including the Gulf of Mexico and US Caribbean areas) include petroleum, sand and gravel, phosphorite, placer deposits of heavy mineral sands, ferromanganese nodules, and fresh water. Although major efforts have been made to search for petroleum, the oil and gas resources of the region are well known only in the western Gulf Shelf and more exploration is under way. Heavy-mineral placer deposits, which may be sources of titanium, gold, rare earths, etc. , have been sampled, but the extent and, therefore, economic value of the deposits have not been identified. Sand and gravel, phosphorite, and ferromanganese nodules all are represented by fairly well established deposits, and only modified market conditions would be necessary to cause detailed exploration and mining.