Factors controlling alpine glaciations in the Sierra Baguales Mountain Range of southern Patagonia (50º S), inferred from the morphometric analysis of glacial cirques

Abstract

The Sierra Baguales Mountain Range, forming the eastern foothills of the Southern Patagonian Andes, has well-developed alpine-glaciated landforms which present an ideal opportunity to study climatic and non-climatic factors that control cirque development and morphology. One hundred and forty-three glacial cirques were studied with reference to 14 morphometric attributes which were analyzed using statistical analysis and GIS methodologies. The cirques were classified into two types using cluster analysis complimented with a composite map based on the attributes, the latter technique that is applied to glacial cirque analysis for the first time. Type 1 cirques are associated with glacial processes isolated from the Southern Patagonian Ice Field (SPIF), developed under locally cold and dry climatic conditions. Type 2 glacial cirques are associated with older, more extensive glacial processes controlled by regional-scale climate variables and the presence of the Pleistocene Ice Sheet. The results show that the development of most of the glacial cirques has been controlled mainly by their aspect, exposure to solar radiation, Southern Hemisphere Westerly winds, and cirque floor slope. Finally, we concluded that our analyses show the evolution of cirques in the Sierra Baguales Mountain Range was not uniform. Cirque glaciers that developed to the west, close to the Southern Patagonian Ice field, have been more dynamic, and therefore their cirques experienced more erosion than those located to the east.