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Abstract Proglacial lakes, whose numbers have been growing around the world, may drive accelerated glacier retreat and provide valuable records of past glacier and climatic changes. Despite their importance, few studies have investigated the sedimentary properties and processes acting within large proglacial lakes. Lago Argentino (LArg) is a 1,500 km2ice‐contact lake on the eastern flank of the Southern Patagonian Icefield. Here, we describe the results from a detailed analysis of 47 sediment cores obtained throughout this lake basin, supplemented with remotely sensed data. We show that: (a) LArg exhibits a seasonal variation in sediment properties (varves); (b) varve formation results from three distinct processes, driven by seasonal changes in glacial sediment input, seasonal changes in fluvial sediment input, and seasonal variations in lake mixing; and (c) distance from glacier calving fronts provides the first‐order control on sediment grain size and accumulation rate. Our findings highlight the exceptional preservation of annual laminations within proglacial lakes, their potential for reconstructing past glacier changes, and their relevance for forecasting future glacier–lake interactions.
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Factors controlling alpine glaciations in the Sierra Baguales Mountain Range of southern Patagonia (50º S), inferred from the morphometric analysis of glacial cirques
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.
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- Award ID(s):
- 1263474
- PAR ID:
- 10085292
- Date Published:
- Journal Name:
- Andean Geology
- Volume:
- 45
- Issue:
- 3
- ISSN:
- 0718-7092
- Page Range / eLocation ID:
- 357; 378
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5027/andgeoV45n3-2974
