Uplift history of the Transantarctic Mountains in the Dry Valleys area, southern Victoria Land, Antarctica, from apatite fission track ages

Apatite fission track ages of basement sampIes from Wright and Victoria Valleys increase systematically with sam pIe elevation.These ages reflect the times at wh ich different sampIes cooled below a temperature of about 100°C and began to retain stable fission tracks.The rate at which the apatite ages change with elevation is largely controlled by the uplift rate. The observed ages range from 154 ± 7 to 66 ± 4 m.y. and indicate a steady, slow uplift over this period at about 15 m/m.y., assuming a constant thermal gradient with time. Taken in conjunction with the present thermal gradient in this area, the youngest ages indicate a greatly increased rate ofuplift during the Cenozoic, and give a reliable older limit to the onset of the Victoria Orogeny.The results indicate that nearly 4 km of uplift has occurred during the Cenozoic, with a minimum average uplift rate of about 55 m/m.y., again assuming the thermal gradient has remained constant over that time.