Dow Jones: The U.S. Geological Survey said Friday that it has proof that the U.S. Gulf of Mexico has a rich concentration of gas hydrate reservoirs, a potential source of natural gas. The agency, part of the U.S. Department of the Interior, said the Gulf is the first U.S. offshore area with documented data that attests a sufficient concentration of gas hydrate resources. Gas hydrate is composed of natural gas and water. The data comes from recent drilling by a government and industry …