Permafrost and hydrogeology of quaternary deposits at Cape Welchness, Dundee Island (Antarctic Peninsula)

Abstract Cape Welchness is an uncovered ice area on Dundee Island (north-east of the Antarctic Peninsula), mostly covered by Holocene-age glacial-glaciomarine deposits of up to 70 m in depth. In some areas, rocks from the Trinity Group and the Gustav Group outcrop. Syngenetic cryounits with an active layer development of 0.8 m and ice content ranging from 6% to 15%, increasing with depth, have been detected. Epigenetic units develop an active layer of up to 1.25 m (6–16% ice content), with similar depth values. Along the coastal zone, cryopeg reaches nearly 8 m in depth, alternating between ice, fresh water and saline water. The low and high plains exhibit extensive areas of open talik. In the low plain, a suprapermafrost summer aquifer with a thickness of 1.25–1.50 m develops. Glacial-fed creeks discharge 98% of the water input, while snow-fed creeks contribute only 0.04 Hm 3 /month. The ponds are divided into those fed by glaciers (linked to open talik) and those fed by precipitation (linked to closed talik). Creeks have an average salinity of 198 mg/l, lakes 190 mg/l and groundwater 223 mg/l. This study focuses on the area of the new Petrel Base, designed to enhance Argentine logistics.