HR: 1340h
AN: T23B-0540    [Abstracts]
TI: Thermal-Mechanical Regime beneath Tarim Basin, Northwestern China and its Implications for Cenozoic Tectonics
AU: * Liu, S
EM: shaowliu@nju.edu.cn
AF: Dept. of Urban and Resources, Nanjing Uninversity, No.22 Hankou Road, Nanjing, 210093 China
AU: Wang, L
EM: lswang@nju.edu.cn
AF: Dept. of Earth Sciences, Nanjing Uninversity, No.22 Hankou Road, Nanjing, 210093 China
AB: As one of the super-large scale sedimentary basins in China, the Tarim basin is also the strategic basement for Chinese `Natural gas transportation from west to east' project. To know its thermal regime is vital for understanding the deformation and oil gas resource in Tarim basin. Integrated the abundant data of geotemperature and rock thermophysical parameters collected and measured in the basin with corresponding geothermal modeling, here we present the characteristics of geotemperature field, thermal evolution and lithospheric thermo-rheological structure of the Tarim basin, along with the implications for formation and deformation of basin and hydrocarbon reservoir. Our results show that the average present-day heat flow of the basin is about 45 mW/m2 and 18-20°/km for geotemperature gradient, respectively. The basin is characterized by lower temperature in a whole. Lateral heterogeneities exist for the distribution of geotemperature field in the basin. The structural units of basin differ much in the geothermal features; generally, the depression areas are of relatively low geotemperature while high for those uplifts and highs in the basin. Thermal evolution modeling of the basin indicated that it has experienced four different phases since basin formation as follows: high heat flow phase from Sinian to Ordovician, thermal attenuation phase during Silurian to late Paleozoic, then stable thermal evolution phase in Mesozoic, and flexural deformation of lithosphere in Cenozoic. The thickness of the thermal lithosphere of basin is 168-192 km, and 25-28km for the crustal brittle-ductile transition depth; the total lithospheric strength is 1.6-7.8*10**13 N/m. The lithosphere beneath basin is characterized by the rigid block with low temperature but large strength, and deform in a whole. Responded to the far field effect of the Cenozoic India-Eurasia collision, the lithosphere beneath Tarim basin is characterized by flexure deformation, resulting in the intensive deformation around representative of rapid uplifts of the surrounding mountains and subsidence in the rim of the basin and mountains to form the foreland basin. Distributions of earthquake activities and GPS observations have verified this deformation pattern. Accordingly, fluids in the formation would immigrate towards the fore bulge belt within basin, which has controlling influences on the formation and distribution of oil and gas in the basin.
DE: 8103 Continental cratons
DE: 8130 Heat generation and transport
DE: 8138 Lithospheric flexure
DE: 8159 Rheology: crust and lithosphere (8031)
DE: 9604 Cenozoic
SC: Tectonophysics [T]
MN: Fall Meeting 2005