Factors driving alpine glaciation in the Sierra Chacabuco and Cordillera Arturo Prat massifs, Patagonia, Chile, based on the analysis of geomorphological features and morphometric development

Sierra Chacabuco and Cordillera Arturo Prat are two small isolated massifs located in Southern Chile which provide an excellent location to study the climatic and physical factors that drive morphometric development and extent in the region. A total of 60 cirques in the two massifs were identified and analyzed for indicators of their past glacial extents through evidence of geomorphological features including moraines, tarns, U-shaped valleys, niche glaciers, and rock glaciers. These cirques were also classified using satellite imagery and GIS analysis. The aspect of each cirque was measured and plotted on rose diagrams. Using various GIS methodologies, eight characteristics of each cirque were determined: length, maximum elevation, minimum elevation, height, floor height, length-to-height ratio, surface area, and current glaciation. Correlations were calculated between each of these characteristics, discounting current glaciation. Here, we report results that indicate different periods of glacial fluctuations through evidence of Holocene advances, glacial stillstands, and extent into valley glaciers. We find that the western Sierra Chacabuco range developed more defined cirques and had longer ice duration than the eastern Cordillera Arturo Prat. The measured characteristics were driven by the massifs' proximity to a moisture source and the elevations. These two factors can be linked to the massifs' separation from the Southern Patagonia Icefield.