Evidence against a young volcanic origin of the Gamburtsev Subglacial Mountains, Antarctica

The Gamburtsev Subglacial Mountains of East Antarctica are among Earth's most enigmatic mountain ranges. They are situated in the middle of Antarctica, buried under hundreds of meters of ice, and reach an elevation of more than 3000 m. These characteristics have given rise to speculation about their origin and composition, in particular whether they are a hotspot or remnants of ancient orogenic events. We studied fluvio-deltaic sands from ODP Site 1166 in Prydz Bay which were deposited prior to the onset of East Antarctic glaciation to address the question of their origin. Results for U-Pb dating of detrital zircons reveal an important age population of ∼530 Ma, which is accompanied by a dominant ⁴⁰Ar/³⁹Ar age population of ∼519 Ma for detrital hornblendes. The data show no sign of young volcanic contributions, suggesting an old continental origin of the mountains, leaving as enigmatic the cause of their great height and size.