Placer Minerals On The U. S. Outer Continental Shelves-Opportunity For Development

摘要

A high potential exists for discovering placer minerals on the Alaskan continental shelf. The eastern Bering Sea shelf may have the greatest potential for locating gold placers. The shelf areas offshore of Nome and Goodnews Bay, Alaska, deserve special emphasis in the search for offshore gold placers. East of Cape Prince of Wales and off St. Lawrence Island there is also potential for heavy mineral placers. Offshore Seaward Peninsula appears to have high potential for tin. The Washington and Dregon Outer Continental Shelf (OCS) offers opportunities-for developing placer deposits. A full suite of heavy minerals occurs along these coasts. Occurrences of gold flakes and platinum with other heavy mineral sands have been found along the Washington coast from Cape Flattery to the Columbia River. Offshore Crescent City, California, has potential for offshore platinum and gold. Kyanite and sillimanite are the dominant heavy minerals on the eastern Gulf of Mexico shelf. The amphibole-pyroxene group are dominant in the western Gulf of Mexico shelf. Heavy mineral placers are abundant and widespread on the Atlantic OCS. Areas offshore of Florida, South Carolina, and Virginia have potential for containing economically viable heavy mineral placers. Many of the shelf sands are titanium rich. Other minerals included in the suite are rutile, ilmenite, zircon, garnet, kyanite, sillimanite, and staurolite. Resource estimates for offshore undiscovered placers range from tens of millions of ounces of gold in Alaska to millions of tons of heavy minerals off the Pacific coast. The Atlantic OCS may contain well over a million tons of titanium alone.