CONICET | Buscador de Institutos y Recursos Humanos

Differentperiglacial studies related to mountain permafrost were carried out in theCentral Andes of Mendoza, Argentina, in the last years. Thesestudies were made especially on rock glaciers. Most important research includedmonitoring of soil temperatures in active layers and the determination of thetop and base mountain permafrost to observe climatic changes as well as the impact of global warming on the Andean cryosphericsystem. Other studies have involvedhydrochemistry and an overview of how groundwater interacts with cryoforms.Hydrological studies in Mendoza are considered strategic because the region issemiarid and needs to improve the management of theresource water for human activities in the oasis as well as for drinkingwater in a changing environment. Expanding Andean wetlands at highaltitudes are studied in order to analyse the C storage. The region corresponds to the most southern part of the DryAndes. Important investigated valleys with permafrost are located inthe basin of the Vallecitos river with a surface of 44.95 km². Thebasin belongs to the Cordón del Plata mountain range, Cordillera Frontal(32˚57' S, 69˚22' W). Sub-basins show > 60% of periglacialenvironment with possible permafrost occurrence from ~3600 m asl on upwards. Theheads of the valley are occupied by debris-covered glaciers. At present, theglacier area has decreased considerably, or even vanished. Thermokarst are also present in the covered glacier area but also insome parts of the rock glaciers indicating ice degradation and at the same timethe occurrence of subterranean glacial ice. At the Morenas Coloradasrock glacier, regional studies were carried out between 1989 and 1992,where the terminal part has been monitored continuously since 1999. This rock glacier showed different temperaturecharacteristics at three monitoring sites in active layers, Balcón I (3560 masl), Balcón I Superior (3590 m asl) and Balcón II (3770 m asl). As a consequence of the thermal changes of the activelayers, the rock glacier shows abrupt movements, particularly in its terminalpart. Thus geodesic measurings were made and resulted in different speeds anddirections. At the monitoring area of Balcón I Superior, which lies on asuperimposed lobe, the geodesic measuring points revealed significant kinematicactivity in the period May 2015 ? February2016, when the largest displacement was approximately 2 m to the South,developing an advance of the front over Balcón I. At Balcón II however, thepoints moved much less, in the order of 0.30 m/yr. On the other hand, atthe Stepanek rock glacier a seasonal hydrochemical monitoring was carried outbetween 2013 and 2017. The objective was to explain groundwater and surfacewater flow, hydrochemistry and to understand the interaction betweengroundwater and the rock glacier. The Stepanek rock glacier fills the valleyand its permafrost affects the water flow. The isotopic results of the watersamples strongly indicate that there is an intra-permafrost water influencefrom the rock glacier, in response of the degradation of permafrost and meltingof ground ice. Due to lithological factors, the Andean periglacial environmentmay indicate altitudinal differences in the hydrogeochemical results. Elevated values of Ni2+,Cd2+ and Zn2+ were detected inthe meltwater runoff. The hydrogeochemical and isotopic research allows theinterpretation of different water paths across the rock glacier. It is expectedthat this becomes more important in the future due to further global warming.

enviar mensaje