The book Los fenómenos periglaciales. Identificación, determinación y aplicación by Dario Trombotto and Ana Lía Ahumada is in the process of being published by the Fundación Miguel Lillo. This book synthesizes the current information about periglacial processes on the basis of the research carried out in Argentina and other parts of South America.
Under the direction of Ana Lía Ahumada, the Northwest Argentina working group of the Institute for Quaternary Geology of the ”Fundación Miguel Lillo” continues working on a high basins inventory of eastern Sierra de Aconquija. A special emphasis is on the water (ice) content of rock glaciers and on hazard assessment in these high mountain areas sensitive to climatic change.
Further monitoring of the rock glacier Morenas Coloradas in the Central Mendoza Andes (Dario Trombotto, IANIGLA, Mendoza) indicated in summer 2004 a temperature of 2.58C at 5 m depth at Balcón I (3560 m asl), i.e. where top of the permafrost permafrost occurred until 1999. Another increase in active layer thickness, although less pronounced (15 cm), could also be observed at Balcón II (3770 m asl). Active layer thickening is accompanied by a reactivation of ancient thermokarst.
Bolivia: The Bolivian (J. Argollo)–Argentinian (R. Villalba) research project ”Cryogenic processes as a major forcing of upper-treeline limit of Polylepis in the Bolivian Altiplano” is aimed at climate variations reconstruction using proxy data from high regions across the Western Americas. Tree-ring data have been collected for the past four years in the southern Bolivian Altiplano. Polylepis tarapacana (queñoa) is a good indicator of interannual precipitation changes and some queñoa cross-sections have been collected between 4500 and 4750 m asl on old volcanoes (five in Bolivia and one in Argentina). Landscape features linked to inactive cryologic processes are common in the area. At the Uturunco volcano (218S, 678W), the upper limit of the queñoa woodlands appears to be controlled by rock streams (Andean kurums) that were probably active during the Little Ice Age. These features are better developed on the S-SW slopes than on N-facing slopes; queñoas can therefore reach higher elevations on these slopes. Cross-sections from Polylepis trees killed by this downslope movement of rock and ice have been used for dating the activation of these cryogenic processes using dendrochronological techniques. Bernard Francou and his team (Institute of Research for Development, France) have established a glacier monitoring network that includes glaciers of the Cordillera Real, Zongo and Chacaltaya (Bolivia, 168S). A summary of the research on the Cerro Caquella rock glacier is ready for publication.
Brazil: The Antarctic working group of Proantar-Brazil (F. Simas and C. Schaefer), a new group in the AASP, continued working on permafrost investigations and chemical processes on King George Island, Antarctica. A summary of their work was published in the proceedings of the 2004 SCAR meeting in Bremen.
Chile: Rock glaciers in the semiarid Andes of Chile are being studied by geomorphologists from the Humboldt University Berlin. On the basis of random sampling and aerial photographs, Alexander Brenning established a regression model correlating relief parameters to rock glacier and glacier distribution in the Santiago and Mendoza Andes. A rock glacier was discovered in the Santiago Andes just 10 km east of the Chilean capital—a striking proof of the need for further permafrost investigation in Chile. First results were presented at the EGU Conference in Nice. Further research on the Punta Negra rock glacier (Santiago Andes) by Tobias Wittkopf includes monitoring ground temperatures between 2500 and 4000 m asl in order to better understand soil-snow-atmosphere heat exchanges (Andreas Lamm).
Ecuador and Perú: A large-scale monitoring programme (B. Francou, IRD) in these countries (together with Bolivia, see above) includes mass balance (energy balance), ENSO events and hydrological balance on several tropical glaciers at the Cordillera Blanca, Yanamarey and Artezonraju in Peru (98S) and in the Ecuadorian Andes (Antizana and Carihauyrazo, appr. 08). A workshop on this topic was carried out in July in Huaraz. Despite smaller retreat rates during cold events (La Niña), tropical glaciers retreat has been accelerating since the late 1970s in an area extending from Ecuador to Bolivia.
Finally, I would like to express my gratitude to the colleagues from different South American countries, Switzerland, Germany and France for their support of the Argentine IPA representation.
Dario Trombotto (firstname.lastname@example.org)