Geology of Mud Volcanoes and Geochemistry of Associated Gas in Southern Taiwan and Its Significance to Petroleum Geology
A plenty of mud volcanos exist in the southern Taiwan,and the geochemistry of mud volcano-associated gas is representative of crustal gas origin rather than volcanic mantle one.The chemical compositions of associated gas are dominated by methane,the content of ethane and propane is very low.Carbon isotope values of methane and carbon dioxide are ranged from-31.7‰ to-35.9‰ and-10.0‰ to-15.2‰,respectively.Helium and Argon isotopes are low,with R/Ra ratios of 0.21-1.34,and 40Ar/36Ar ratios of 304.6-330.0.Geochemistical parameters of associated gas suggest that the mud volcano-associated gas as thermally decomposed hydrocarbon gas would be mainly sourced from the Neogene marine source rock with big thickness.It is helpful to understand the particular mechanism of accumulation of associated-gas based on information of geology of mud volcanoes and geochemistry of associated-gas gas.