Submarine seep of carbon dioxide in Norton Sound, Alaska

Earlier workers have described a submarine gas seep in Norton Sound having an unusual mixture of petroleum-like, low-molecular-weight hydrocarbons. Actually, only about 0.04 percent of the seeping gas is hydrocarbons and 98 percent is carbon dioxide. The isotopic compositions of carbon dioxide (δ¹³C_PDB = –2.7 per mil) and methane (δ¹³C_PDB = –36 per mil) where PDB is the Peedee belemnite standard) indicate that geothermal processes are active here.