Petroleum and Mineral Resources in Exclusive Economic Zone

George T. Moore

The United States Exclusive Economic Zone (EEZ) was established by presidential proclamation on March 10, 1983. It gives the United States the sovereign right over living and nonliving resources out to 200 nmi from its coast and island territories, an area of about 6,100,000 mi². Within this vast frontier, petroleum, metallic, and nonmetallic mineral deposits have been discovered or are believed to exist.

Petroleum exploration has moved into progressively deeper water throughout this century, and has expanded to include all the varied and complex margins of North America. Some areas (e.g., the Gulf of Mexico, offshore California, and the North Slope of Alaska) have become major petroleum provinces with considerable future deep-water potential. Other regions (e.g., the Atlantic margin and Gulf of Alaska) have been disappointing. Too little is known about basins associated with the Pacific volcanic islands to evaluate them as yet.

Mineral deposits located within the territorial jurisdiction of the EEZ can be divided into five broad categories: polymetallic sulfides, ferro-magnesian crusts and nodules, phosphorite, heavy mineral placers, and nonmetallic minerals. Sulfides of iron, manganese, copper, and zinc are deposited from rising mineral-rich solutions within active spreading centers such as the Gorda Rise and Juan de Fuca Ridge off the U.S. West Coast. Deposits of ferromagnesian nodules and crusts containing nickel, copper, and especially cobalt occur on the Blake Plateau and on many of the seamounts and volcanic islands of the Pacific. Phosphorite occurs off southern California and from North Carolina to Florida. Rivers that flow through mineral districts can produce placers on the coast as well as on the ontinental shelf. A variety of nonmetallic mineral deposits exists in the EEZ, such as sand and gravel, carbonate, precious coral, sulfur, and salt.

These petroleum and mineral deposits can be considered resources. However, only continued research, extensive exploration, advances in technology, market price, and demand will determine whether they can be recovered economically.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.