Cycles of erosion and deposition during the Permo-Carboniferous glaciation in the Transantarctic Mountains

Abstract

At two localities adjacent to Hatherton Glacier, Darwin Mountains, a thick glacio-lacustrine sequence underlies the main diamictite facies of the Darwin Tillite (Metschel Tillite), and at one of these locations a glacio-lacustrine sequence also conformably overlies the diamictite. These deposits record the initial advance and final retreat of the Gondwana ice cap. Other, pro- and periglacial phases within these sequences record several minor advances and retreats of the ice sheet. Carbonaceous sediments above and below the main diamictite phase show that vegetation was established near the ice margin, suggesting that present-day ice margin temperatures are colder than those experienced during the Permo-Carboniferous (Gondwana) glaciation. It appears that there was little or no erosion of the Devonian Taylor Group which underlies the glacial sequence. The apparent erosional nature of the contact between the Permo-Carboniferous glacial sequence and the overlying Permian coal measures is attributed to surface winnowing of unconsolidated tills and locally the units are conformable.