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

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Abstract

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.
EGU23-2290, updated on 25 May 2023
https://doi.org/10.5194/egusphere-egu23-2290
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
Understanding the spatial distribution of potentially ice-rich block-
and talus slopes in the Agua Negra catchment, Dry Andes,
Argentina
Tamara Köhler1, Diana A. Ortiz1, Anna Schoch-Baumann1, Rainer Bell1, Melanie A. Stammler1,
Lothar Schrott1, and Dario Trombotto Liaudat2
1University of Bonn, Department of Geography, Bonn, Germany (tkoehler@uni-bonn.de)
2IANIGLA-CONICET, Instituto Argentino de Nivologia, Glaciología y Ciencias Ambientales. Av. Dr. Adrian Ruiz Leal, M5500
Mendoza, Argentina (dtrombot@mendoza-conicet.gob.ar)
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.
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Article
Full-text available
Rock glaciers are a characteristic landform of semiarid subtropical mountains. In many catchments of the high Andes where permafrost occurs, they cover larger areas than that of glacier ice. On the basis of geomorphological evidence and different measurements (e.g. soil temperature, discharge and seismic refraction soundings), the hydrological significance of rock glaciers and permafrost in the Agua Negra basin is demonstrated in this paper. Even without considering the other permafrost areas of the catchment, the estimated volume of ice in the active rock glaciers of the basin corresponds to about 70% of that in the glaciers. Discharge measurements confirm that melting of frozen ground and meltwater from areas underlain by permafrost represent an important share (approx. 30%) of the river discharge during the summer months. In the periglacial environment of semiarid mountains, rock glaciers have two important roles: first, they are important water storage and water input systems; and, second, they are dominant in the talus transport systems. From the debris volumes of rock glaciers, rockwall retreat rates can be estimated.
IANIGLA-Inventario Nacional de Glaciares y Ambiente Periglacial. Informe de la subcuenca del río Blanco
  • Ianigla-Conicet
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.