Physiographic and climatic controls on the spatial distribution of rock glaciers and periglacial landforms in the Dry Andes, San Juan, Argentina

Abstract

Recent environmental legislation in Argentina seeks to protect and preserve glacier ice, including that in ice-saturated landforms with debris cover like many rock glaciers and protalus ramparts, as important water reserves in the Dry Andes. Although ice exposed at the surface is easy to identify, the extent of buried ice coverage – and therefore its impact on regional hydrology – is not well known in this remote and little-studied terrain. This study investigates the physiographic, geographic, and climatic factors controlling the distribution of rock glaciers and periglacial landforms using a digital inventory spanning a 2400 km2 area of the Dry Andes in the San Juan Province, Argentina. Multivariate analyses of the inventory data reveal that the presence and size of these landforms are largely controlled by the properties of their adjacent talus supply area. In the talus supply area, colder annual ground temperatures, higher average elevations, larger surface areas, and south- trending aspects highly correlate with larger and less elongated periglacial landforms. These results and the statistics of the inventory indicate the preferred conditions of elevation, slope, aspect, and solar radiation, where rock glaciers and other periglacial landforms, and potentially ground ice, are located. The methods and results provided in this study can be applied to other areas in the Dry Andes to identify analogous conditions, aiding land-use and environmental protection decisions.