Circum-Tethys and circum-Pacific basins

Mesozoic circum-Tethys and circum-Pacific basins, which are genetically related to the Tethys and circum-Pacific tectonic zones, are the regions with the most abundant petroleum and natural gas. These two tectonic systems intersect in China and most of the Mesozoic basins in China are closely associated with these two systems. Circum-Tethys basins developed against a background of crustal compression. They are the result of compressional thrusting and the resultant sinking of the crust. Warm-moderately hot foreland basins are the most representative. Hydrocarbon source rock evolved slowly. Threshold depth of oil-generation is great and petroliferous beds have relatively older ages and occur at greater depths. Circum-(west) Pacific basins were formed against a background of extension and thinning of the crust and frequent geothermal activities. Hot rift basins are the most representative. Hydrocarbon source rock evolved rapidly. Threshold depth of oil-generation is small and petroliferous beds have relatively younger ages and occur at shallower depths.