Periglacial study in the Patagonian Andes

Abstract

This paper contains the results of a part of my study on periglacial morphology at the eastern slope of „Hielo Patagonico Norte" in the Patagonian Andes during the ,,Expedicion Chileno Japonesa Andes Patagonicos 1958" which was done during January, February and March, 1958.

Having traced up the Rio Baker and Rio Colonia Valleys, we crossed the virgin waters of Lago Colonia to the unexplored shore where we set up our base camp at the edge of the Colonia Glacier at an altitude of 240 m. When our climbing group was engaged with the virgin peak of ,,Cerro Arenales" (3 437 m) I made several brief explorations around the base camp, and found an interesting small lake which we named ,,Lago Arco" in the lower part of the glacier.

In midsummer the lake-basin was empty with a huge moraine in the bottom of the basin, while it was full of water the air photograph taken by the Chilean Air Force early in spring, 1945 shows a half-moon-shaped island suggesting the top of the moraine. I have heard of the mysterious flood which occurs once every summer along the Rio Baker, resulting serious loss of cattle. I proved the hypothesis that flood might be caused by water from the lake. Such is one of the characteristic features of the rapidly retreating glacier of the region, and I am particularly interested in analyzing many others within the Rio Baker Region by using several air photographs available.