Abstract

LO VECCHIO REPETTO, Andrés. Santa Cruz river basin’s glacier dynamic: fresh water of future. Bol. estud. geogr. [online]. 2021, n.116, pp.187-216.  Epub June 26, 2023. ISSN 2525-1813.

The largest glacier area in Argentina is located in the Santa Cruz River Basin (CRS), Southern Patagonian Andes. The CRS concentrates 35% of the entire national glacier cover (including the sub-Antarctic islands), and 52% if only the Andes are considered. Its 3023 km2 are distributed in a thousand glaciers, although between seven of them accumulate ~80% of that area (Viedma, Upsala, Onelli, Spegazzini, Mayo, Ameghino, and Perito Moreno). These seven glaciers end in proglacial lakes, which stimulate processes of acceleration, fracture, and detachment of glacial ice (detachment glaciers). The thesis aims to determine the multiscale relationships between the dynamics of the detachment glaciers of the CRS, the natural triggering processes, and their impacts on the geographic space. To this end, the analysis of the last two decades is proposed through different satellite platforms and the thematic information available. In this work, the glaciological indicators analyzed are frontal position changes and supraglacial melting events. For synthesis purposes, the results show a cumulative retraction of 19 ± 0.3 km during the whole study period, although with heterogeneous individual behaviors. Between 1985 and 2017 the Upsala glacier retreated 8287 ± 60 m, at the same time Moreno glacier advanced 101 ± 60 m. Spegazzini glacier is another glacier that sustained its position in that period, immediately south of Onelli glacier which retreated 3069 ± 60 m. The above suggests the multicausal of glacial dynamics and the inexistence of a single forcer. In terms of melting events (2001-2016), the extent occupied by these has a marked seasonality, frequent during the summer months even at high summits (>3000 m). During the warm period (October/April) more than 50% of the glacier area was melting (with maximums of 75% in the summer of 2013). In contrast, in the cold phase, they were drastically reduced and even absent in the months of June-July. In CRS, melt events began to increase from 2010, with a positive trend. The consequences of glacial dynamics have played a key role in the possibilities for the configuration of humanized spaces. These places are structured according to these dynamics, either because of exposure to glacial hazards or because they represent the main source of foreign exchange for the basin: glacier tourism.

Keywords : Glaciers and society; Santa Cruz river basin; Historical glacial dynamics.

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