Multi-spherical interactions and mechanisms of hydrocarbon enrichment in the Southeast Asian archipelagic tectonic system

Global cooling began since 50 Ma, but a warm climate was maintained in the archipelagic tectonic system in Southeast Asia where a wealth of Cenozoic oil and gas resources was formed and preserved. From the perspective of Earth system, this study analyzes Cenozoic tectonic activities, climatic and environmental evolution, and petroleum enrichment in Southeast Asia, and provides the following insights: (1) Subduction of oceanic plates and the extension of overlying continental lithosphere resulted in widespread volcanic eruptions as well as the formation of rift basins and shallow marine shelves, leading to complex interactions between deep tectonic processes and Earth’s surface including mountains, basins, and seas. (2) Microcontinental accretion and prolonged stay in equatorial low-latitude regions have changed trade winds into monsoons, altered ocean current pathways and flow rates, and profoundly affected rainfall and climate. (3) The archipelagic tectonic system, coupled with a hot and rainy climate, fostered tropical rainforests, mangroves, and phytoplankton, providing abundant organic matter and promoting the development of petroleum resources. (4) Combinations of rift basin development and marine transgression and regression led to an effective superposition of source-reservoir-seal combinations from multiplepetroleum systems. Rapid deep burial of organic matter and high geothermal gradients facilitated the generation and large-scale accumulation of oil and gas. (5) Multi-spherical (such as atmosphere, biosphere, hydrosphere and lithosphere) interactions on the Earth, which resulted from the convergence of multiple tectonic plates, are believed as the primary driver for exceptional enrichments of Cenozoic oil and gas resources in Southeast Asia. These understandings are significant for developing theories of oil and gas enrichment under the guidance of Earth System Science. In order to continue making significant oil and gas exploration discoveries in the deep-layers, deep-waters, and unconventional oil and gas fields of Southeast Asia, attention should be paid to the oil and gas resource effects of the collision between Australia and Sunda blocks and the high-temperature and high-rainfall climate environment, and efforts should be made to develop economic development and CO 2 sequestration technologies for offshore CO 2 -rich gas fields.