WORLDWIDE DISTRIBUTION OF SUBAQUATIC GAS HYDRATES

Sediments containing natural gas hydrates occur worldwide on continent al and insular slopes and rises of active and passive margins, on cont inental shelves of polar regions, and in deep-water (> 300 m) environm ents of inland lakes and seas. The potential amount of methane in natu ral gas hydrates is enormous, with current estimates at about 10(19) g of methane carbon. Subaquatic gas hydrates have been recovered in 14 different areas of the world, and geophysical and geochemical evidence for them has been found in 33 other areas. The worldwide distribution of natural gas hydrates is updated here; their global importance to t he chemical and physical properties of near-surface subaquatic sedimen ts is affirmed.