Significant deposits of hydrocarbons are probably present beneath the continental margin of Antarctica in the areas of the Ross, Amundsen, Bellingshausen, and Weddell Seas. The onshore areas of Antarctica have uncertain petroleum potential, because the sedimentary rocks that do extend above the ice sheet are largely metamorphosed and intruded by igneous rocks. Large basins containing sedimentary rock may underlie the thick (average 3 km) moving ice sheet (e.g., Wilkes and Polar basins and areas west of the Pensacola Mountains).

Widely spaced marine geophysical surveys (by Eltanin and other ships) have been carried out over parts of the continental shelf, but only the Norwegian (1976-77) and German (1977-78) expeditions have collected modern deep-penetration multichannel seismic data. No systematic aeromagnetic surveys of the continental margins exist, although data from the early 1960s to 1978 suggest a section of sedimentary rocks several kilometers thick above magnetic basement. The Deep Sea Drilling Project (DSDP) sampled rocks that were as old as Miocene beneath the Ross Sea continental shelf (maximum penetration of 443 m) and as old as Oligocene to early Miocene beneath the Bellingshausen Sea continental rise. The only traces of hydrocarbons recovered so far are methane, ethane, and ethylene from DSDP c res beneath the Ross Sea shelf.

Comparisons with other continents in the Southern Hemisphere suggest the likelihood of thick Cretaceous and Tertiary sedimentary sections beneath the continental margins of the Ross, Amundsen, Bellingshausen, and Weddell Seas. Some of the areas of other continents adjacent to these parts of the Antarctic continental margin in the Gondwanaland reconstruction contain significant amounts of oil and gas. By analogy, therefore, the Antarctic continental margin may also. Published estimates suggest that undiscovered petroleum resources may be in the range of tens of billions of barrels in place.

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