In February 2006 the working group directed by Ana L. Ahumada (Inst. of Quaternary Geology and Palaeoclimates, Miguel Lillo Foundation) installed data loggers on the cryoplanation surface (27º7’ S, 66º2’ W) at Abra de la Apacheta, Sierra de Aconquija, Tucumán, at 4825 m asl, to monitor temperatures, as air temperatures above 2000 m asl were not available in that region.
In March, Dario Trombotto (Argentinean Institute for Snow, Ice and Environmental Research IANIGLA, Mendoza, Argentina) led an expedition to the peak of the Peteroa volcano (35°15’ S) in the southern Mendoza Province, on the Chilean boarder. The volcano is active and belongs to a volcanic group with a maximum height of app. 4100 m asl. The top, which has been almost entirely glaciated until a few years ago, today is periglacial with high mountain permafrost clearly observable from a height of 3400 m asl. Hidden massive ice alternates with sediments of fluvio-glaciogenic origin and moraines. New cryogenic forms with deformations caused by the pressure of ground ice were discovered. Glaciers show a remarkable retreat, at the peak and on the slopes of the Argentine side, this favours formation of new permafrost. The retreat is assumed to be partly due to the general warming observed in the Central Andes of Mendoza, but doubtlessly also caused by volcanic activity. The area is crucial for future geocryological research.
The CONCORD Symposium «Climate Change: Organizing the Science for the American Cordillera» was held April 4-6, 2006 at IANIGLA, Mendoza. More than 160 researchers attended, discussed mountain ecosystems data and defined the use of resources and the role of institutions related to mountain management to preserve the social and economic well-being of mountain communities in this part of South America. Changes in the alpine cryosphere may represent some of the earliest signs of largescale climate change. The reduction of the snow- and icecovered areas not only functions as an indicator of change, but also provides powerful feedbacks through changes in albedo. Moreover, permafrost thawing destabilizes slopes in high relief areas, leads to landslides and rockfalls and endangers water supply of arid areas. Conference materials including abstracts and presentations are available at: <http://mri.scnatweb.ch/content/category/7/44/66>.
In Chile, the team lead by Hilmar Schröder (Univ. Humboldt, Berlin, Germany) is developing research in two directions, as a part of an ongoing programme on present and former periglacial environments: (1) Comparative morphogenesis of Richter denudation of slopes in periglacial and frost-free environments; and (2) Genesis of lake basins dating from the late Quaternary and Holocene in the Tinguiririca Valley and in the basin of Cancosa. Another joint project of the Humboldt University and the Unit of Geocryology, Mendoza (D. Trombotto, IANIGLA) entitled «Comparative periglacial morphology for quantification of solifluction movement in times of climatic change» is planned to start in 2007. This project will take place in the Chilean and in the Argentine Andes, collaborating with specialists, who studied solifluction in the Swiss Alps and the mountains of Kazakhstan.
In Ecuador, Bolívar C. Correa (National Institute of Meteorology and Hydrology INAMHI, Quito) is carrying out glaciological and geocryological research of the volcano Antisana in the Equatorian Andes (0°28’30" S, 78°08’55" W, 5760 m asl). Glaciers on the Antisana are undergoing large retreat. Observations of the dynamics of the terminal part of the Los Crespos Glacier reveal retreat and movement of the ice-cored moraine, creeping down the valley probably by creeping of the dead ice they contain. Such landforms can be observed in most valleys of the Equatorian Andes, and is now studied by new research programmes.
In Europe, D. Trombotto is collaborating with Victoria Alonso (Univ. of Oviedo, Asturias, Spain). The Miro region in the Cantabrian Cordillera has been mapped and studied geomorphologically, displays a great variety of fossil periglacial landforms including rock glaciers, giant sorted stripes and cryogenic slopes. Intense cryogenic activity is observed since the ice retreat after the Last Glacial Maximum; when ice thickness in the valleys was up to 400 m. Periglacial forms seem to have been very active during the Postglacial age, including different Neoglacial periods.
Dario Trombotto ([email protected])