APPROACH ON THE RELATION AMONG ANOXIC ENVIRONMENT, SOURCE ROCKS AND SUBAQUEOUS VOLCANIC ACTIVITY OF LOWER PALEOZOIC IN NORTH DABA AREA

Lower Paleozoic of North Daba area consists of volcanic rocks,orga-nic-rich argillaceous rocks and siliceous rocks.Its kerogen type is sapr-opelic with high content of organics.The source rocks are rich in fluor-ine and sulfur,and bear a direct relation to subaqeous volcanic activity as indicated by fluorine and s34S of pyrite.Large quantity of H₂S,SO₂,SO₃,and CO₂ were extruded in the process of subaqeous volcanism,which caused chemical action with oxygen and water,and gravity differentiation of sea water,and provided good conditions for organic pres-ervation.As CH₄ entered atomsphere,combution took place with heat release,growth was promoted,which would provide material basis for oil and gas generation.