Deep thermal structure of Southeast Asia constrained by S-velocity data

摘要: Southeast Asia, located in the southeastern part of Eurasian Plate, is surrounded by tectonically active margins, exhibiting intense seismicity and volcanism, contains complex geological units with a perplexing evolution history. Because tectonic closely related to deep thermal structure, an accurate estimation lithosphere structure thickness important extracting information on tectonics geodynamics. However, there are significant uncertainties calculated state constrained only observed surface heat flow. In this study, order obtain better-constrained state, we first calculate Asia employing empirical relation between S-velocity temperature, then estimate base from temperature-depth profiles. The results show that, general, temperature higher than dry mantle solidus below top seismic low-velocity zone, possibly indicating presence partial melt asthenosphere, particularly beneath oceanic basins such as South China Sea. at depth 80 km rifted Thailand Rift Basin, Bay, Andaman Sea, Sea about 200 °C plateaus subduction zones Khorat Plateau, Sumatra Island, Philippine Trench regions. We suggest that relatively cold thick block Plateau has not experienced internal deformation might be extruded rotated rigid response Indo-Eurasia collision. Our flow mainly dominated state. There anomaly Leiqiong area areas adjacent northern margin high-temperature thin well-known controversial Hainan plume. lithosphere-asthenosphere boundary uplift along Xisha Vietnam margin, western which corresponds volcanic belt around area, indicate upwelling hot materials. values 100 120 km depths through most regions 1400–1500 1550–1600 °C, respectively, nearly uniform small difference. also becomes thinner continent blocks toward basins, smaller 65–70 km estimated approximately 1400 °C isotherm shows good correlation setting.