Tectonics and metallogeny of mainland Southeast Asia — A review and contribution

The Southeast Asia region is endowed with a diversity of mineral resources, notably porphyry-related skarn, epithermal and sediment-hosted/orogenic gold deposits. Formation of these deposits was associated with a long and complex tectonic history of Gondwana supercontinent break-up, arc magmatism, backarc basin development, together with arc–continent and continent–continent collisions that created the present-day mainland SE Asia. This paper summarizes historical and current SE Asian geological research and ore deposit studies. Here we present a new tectonic and metallogenic model for Phanerozoic mainland SE Asia. From this model, we conclude that incipient arc/backarc basin magmatism is the key to the formation of many important ore deposits in the Truong Son and Loei fold belts, the two major metallogenic belts in mainland SE Asia. In addition, Triassic to Cenozoic arc–continent and continent–continent collisions have led to the formation of many sediment-hosted/orogenic gold deposits in the Sukhothai and the Sibumasu terranes. Oblique Cretaceous to Recent subduction along the Andaman–Sunda trench was responsible for gold and copper–gold–molybdenum porphyry and epithermal mineralization along the Kawlin–Wutho–Mt Popa arc in Myanmar in the north and the Sumatran volcanic arc in the south. We anticipate that the present emphasis on exploring for shallower level epithermal deposits will increasingly lead to exploration for deeper level porphyry- and porphyry-related skarn systems in the coming decades.