Antarctic crustal thickness from satellite gravity: Implications for the Transantarctic and Gamburtsev Subglacial Mountains

摘要

Crustal thickness models are fundamental to understand the tectonic evolution of continents and constrain geodynamic models of their physiographic features. Of particular interest in Antarctica are the crustal thickness variations under the Transantarctic Mountains and Gamburtsev Subglacial Mountains, whose formation mechanisms are still debated. We have used a mean, global gravity field from the Gravity Recovery and Climate Experiment (GRACE) to estimate the depth to the Moho in East and West Antarctica through gravity inversion. We then combined the depth to Moho and known topography to estimate the total crustal thickness. Thick crust is resolved along the full length of the Transantarctic Mountains with a maximum crustal thickness of 46 km predicted near the pole and thinner (similar to 40 km) crust in both northern Victoria Land and under the Pensacola Mountains. Within East Antarctica, the model predicts crust over 40 km thick below the Gamburtsev Subglacial Mountains, which may be the result of a Neoproterozoic suture zone underlying the ice sheet. In addition to addressing long-standing questions about the nature of East Antarctica's major mountain ranges, an improved estimate of crustal thickness variability may improve long-wavelength geodynamic and glaciological models of the continent.