Temperature, lithosphere-asthenosphere boundary, and heat flux beneath the Antarctic Plate inferred from seismic velocities

• Published in: Journal of Geophysical Research: Solid Earth
• Main Authors: An, Meijan, Wiens, Douglas, Zhao, Yue, Feng, Mei, Nyblade, Andrew, Kanao, Masaki, Li, Yuansheng, Maggi, Alessia, Lévêque, Jean-Jacques
• Other Authors: National Institute of Polar Research Tokyo (NiPR), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-07-BLAN-0147,CASE-IPY,Concordia Antarctic Seismic Experiment (International Polar Year)(2007)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; Antarctic; Antarctic Peninsula; East Antarctica; The Antarctic; West Antarctica; Antarc*; Antarctica
• Online Access: https://hal.archives-ouvertes.fr/hal-01239984; https://hal.archives-ouvertes.fr/hal-01239984/document; https://hal.archives-ouvertes.fr/hal-01239984/file/2015JB011917.pdf; https://doi.org/10.1002/2015JB011917

International audience We estimate the upper-mantle temperature of the Antarctic Plate based on the thermoelastic properties of mantle minerals and S velocities using a new 3-D shear velocity model, AN1-S [An et al., 2015, JGR]. Crustal temperatures and surface heat fluxes are then calculated from the upper-mantle temperature assuming steady-state thermal conduction. The temperature at the top of the asthenosphere beneath the oceanic region and West Antarctica is higher than the dry mantle solidus, indicating the presence of melt. From the temperature values, we generate depth maps of the lithosphere–asthenosphere boundary and the Curie-temperature isotherm. The maps show that East Antarctica has a thick lithosphere similar to that of other stable cratons, with the thickest lithosphere (~250 km) between Domes A and C. The thin crust and lithosphere beneath West Antarctica are similar to those of modern subduction-related rift systems in East Asia. A cold region beneath the Antarctic Peninsula is similar in spatial extent to that of a flat-subducted slab beneath the southern Andes, indicating a possible remnant of the Phoenix Plate, which was subducted prior to 10 Ma. The oceanic lithosphere generally thickens with increasing age, and the age–thickness correlation depends on the spreading rate of the ridge that formed the lithosphere. Significant flattening of the age–thickness curves is not observed for the mature oceanic lithosphere of the Antarctic Plate.