Understanding the spatial distribution of potentially ice-rich block- and talus slopes in the Agua Negra catchment, Dry Andes, Argentina

Within the extensive periglacial belt of the dry Andean high mountain range (17°30’S to 35°S), the most visible expression of creeping mountain permafrost is the occurrence of rock glaciers, which have been studied systematically in the last decades (e.g. Schrott, 1996; Trombotto et al., 1999; Halla et al. 2021). Active, inactive and relict rock glaciers are included in regional and national inventories (e.g. IANIGLA-CONICET 2018), whereas the spatial distribution, internal structure and ice content within block- and talus slopes have not been explored. Thus, there is a lack of explanatory approaches and analytical data on their local and regional distribution patterns and formative controls, despite these landforms being widespread and characteristic elements in the Upper Agua Negra catchment (ca. 30°S 69°W, Province San Juan, Argentina) and covering more than 70 % of its area. We hypothesize that the permafrost bodies and the seasonally frozen active layer of these periglacial landforms store significant amounts of ice and contribute to runoff during summer months, rendering them important water reservoirs and decisive components of the water balance in the high-Andean desert landscape. Especially in light of global climate change, understanding the spatial distribution of potentially ice-rich permafrost landforms is imperative to assess available water resources, water quality and their evolution.

A holistic inventory of key cryogenic landforms with focus on block- and talus slopes will be compiled for the Agua Negra catchment. Using field and remote sensing-based geomorphological mapping (based on e.g. 12 m resolution TanDEM-X and 1 m Pléiades data), published data and statistical modeling techniques, the spatial heterogeneity of cryospheric landforms and their formation controls will be analyzed. Our regional inventory will complement the existing “Inventario Nacional de Glaciares y Ambiente Periglacial” (IANIGLA-CONICET 2018) and will further provide the basis for a first assessment of the hydrological importance of these cryogenic landforms.

Halla, C., Blöthe, J.H., Tapia Baldis, C., Trombotto Liaudat, D., Hilbich, C., Hauck, C., Schrott, L., 2021. Ice content and interannual water storage changes of an active rock glacier in the dry Andes of Argentina. The Cryosphere, 15, 1187-1213.

IANIGLA-CONICET, Ministerio de Ambiente y Desarrollo Sustentable de la Nación (2018). IANIGLA-Inventario Nacional de Glaciares y Ambiente Periglacial. Informe de la subcuenca del río Blanco. Cuenca del río San Juan, p. 62.

Trombotto, D., Buk, E.,  Hernández, J., 1999. Rock glaciers in the Southern Central Andes (appr. 33° S.L.), Mendoza, Argentina: a review. Bamberger Geographische Schriften, Selbstverlag des Faches Geographie an der Universität Bamberg, Germany, 19, 145-173.

Schrott, L., 1996. Some geomorphological-hydrological aspects of rock glaciers in the Andes (San Juan, Argentina). Zeitung für Geomorphologie, Supplementband 104, 161-173.