Dry Andes

Dry Andes
Field of penitentes on the upper Río Blanco, Central Andes of Argentina
Highest point
Peak	Aconcagua
Elevation	6,961 m (22,838 ft)
Dimensions
Length	1,200 km (750 mi)
Geography
Country	Chile, Argentina, Bolivia
Parent range	Andes

The Dry Andes (Spanish: Andes áridos) is a climatic and glaciological subregion of the Andes. Together with the Wet Andes it is one of the two subregions of the Argentine and Chilean Andes. The Dry Andes runs from the Atacama Desert in northern Chile and Argentina south to a latitude of 35°S in Chile. In Argentina the Dry Andes reaches 40°S due to the leeward effect of the Andes. According to Luis Lliboutry the Dry Andes can be defined after the distribution of penitentes.^[1] The southernmost well developed penitentes are found on Lanín Volcano.

Paleogeography, paleoclimatology and paleoglaciology

Though precipitation increases with the height, there are semiarid conditions in the nearly 7000 m towering highest mountains of the Andes. This dry steppe climate is considered to be typically of the subtropic position at 32-34° S. Therefore, in the valley bottoms do not grow woods but only dwarf scrub. The largest glaciers, as e.g. the Plomo glacier and the Horcones glaciers do not even reach 10 km in length and have an only insignificant ice thickness. At glacial times however, c. 20 000 years ago, the glaciers were over ten times longer. On the East-side of this section of the Mendozina Andes they flowed down to 2060 m and on the West-side to c. 1220 m asl.^[2][3] The massifs of Cerro Aconcagua (6962 m), Cerro Tupungato (6550 m) and Nevado Juncal (6110 m) are situated deca-kilometres away from each other and were connected by a joint ice stream network. Its dendritic glacier arms, i.e. components of valley glaciers, were up to 112.5 km long, over 1020, i.e. 1250 m thick and overspanned a vertical distance of 5150 altitude metres. The climatic glacier snowline (ELA) was lowered from currently 4600 m to 3200 m at glacial times.^{[4][5][6][7][8][9][10][11][12]}

References

1. "Glaciers of the Dry Andes". Louis Lliboutry, USGS. Retrieved 2008-12-21.
2. Kuhle, M. (2011): The High-Glacial (Last Glacial Maximum) Glacier Cover of the Aconcagua Group and Adjacent Massifs in the Mendoza Andes (South America) with a Closer Look at Further Empirical Evidence. Development in Quaternary Science, Vol. 15 (Quaternary Glaciation - Extent and Chronology, A Closer Look, Eds: Ehlers, J.; Gibbard, P.L.; Hughes, P.D.), 735-738. (Elsevier B.V., Amsterdam).
3. Brüggen, J. (1929): Zur Glazialgeologie der chilenischen Anden. Geol. Rundsch. 20, 1–35, Berlin.
4. Kuhle, M. (1984): Spuren hocheiszeitlicher Gletscherbedeckung in der Aconcagua-Gruppe (32-33° S). In: Zentralblatt für Geologie und Paläontologie Teil 1 11/12, Verhandlungsblatt des Südamerika-Symposiums 1984 in Bamberg: 1635-1646.
5. Kuhle, M. (1986): Die Vergletscherung Tibets und die Entstehung von Eiszeiten. In: Spektrum der Wissenschaft 9/86: 42-54.
6. Kuhle, M. (1987): Subtropical Mountain- and Highland-Glaciation as Ice Age Triggers and the Waning of the Glacial Periods in the Pleistocene. In: GeoJournal 14 (4); Kluwer, Dordrecht/ Boston/ London: 393-421.
7. Kuhle, M. (1988): Subtropical Mountain- and Highland-Glaciation as Ice Age Triggers and the Waning of the Glacial Periods in the Pleistocene. In: Chinese Translation Bulletin of Glaciology and Geocryology 5 (4): 1-17 (in Chinese language).
8. Kuhle, M. (1989): Ice-Marginal Ramps: An Indicator of Semiarid Piedmont Glaciations. In: GeoJournal 18; Kluwer, Dordrecht/ Boston/ London: 223-238.
9. Kuhle, M. (1990): Ice Marginal Ramps and Alluvial Fans in Semi-Arid Mountains: Convergence and Difference. In: Rachocki, A.H., Church, M. (eds.): Alluvial fans - A field approach. John Wiley & Sons Ltd, Chester-New York-Brisbane-Toronto-Singapore: 55-68.
10. Kuhle, M. (1990): The Probability of Proof in Geomorphology - an Example of the Application of Information Theory to a New Kind of Glacigenic Morphological Type, the Ice-marginal Ramp (Bortensander). In: GeoJournal 21 (3); Kluwer, Dordrecht/ Boston/ London: 195-222.
11. Kuhle, M. (2004): The Last Glacial Maximum (LGM) glacier cover of the Aconcagua group and adjacent massifs in the Mendoza Andes (South America). In: Ehlers, J., Gibbard, P.L. (Eds.), Quaternary Glaciation— Extent and Chronology. Part III: South America, Asia, Africa, Australia, Antarctica. Development in Quaternary Science, vol. 2c. Elsevier B.V., Amsterdam, pp. 75–81.
12. Kuhle, M. (2011): The High-Glacial (Last Glacial Maximum) Glacier Cover of the Aconcagua Group and Adjacent Massifs in the Mendoza Andes (South America) with a Closer Look at Further Empirical Evidence. Development in Quaternary Science, Vol. 15 (Quaternary Glaciation - Extent and Chronology, A Closer Look, Eds: Ehlers, J.; Gibbard, P.L.; Hughes, P.D.), 735-738. (Elsevier B.V., Amsterdam).