Deciphering a Large-Scale, Wind-Dominated Landscape in the Central Andes: Aeolian Topography in the Salina del Fraile Depression, Southern Puna Plateau
Abstract
Topographic relief results from an interplay between erosion and tectonics, but aeolian processes are often assumed to be of minor importance in orogenic belts. Here, we describe a vast landscape in the southern Puna Plateau in the Central Andes as a product of extreme wind erosion. Using structural mapping and cross-sections, geomorphological observations, and geochronologic data, we argue that wind erosion was primarily responsible for the formation of the Salina del Fraile, a rhomboidal depression 300 km2 in area with 900 m of topographic relief, which exposes a series of compressional anticlines. Anticlinal folding exhumed friable Paleogene strata that were more easily eroded than overlying sandstones and conglomerates. Structural cross-sections show that up to 1.9 km of strata were eroded during the last 8.2 to 17 Ma, an average rate of 0.05 to 0.2 mm/yr. In addition to well-known landforms associated with aeolian erosion—yardangs, pans, desert pavements, and megaripples—the Salina del Fraile contains puzzling large-scale features, such as smoothed mesas and ridges, which we interpret as products of ongoing aeolian erosion. We compare the Salina del Fraile to erosional landforms in the Syrian Arc Fold Belt, which share similarities in form and geologic setting, but are distinguished by their fluvial characteristics. By analogy to these fluvial landforms, the Salina del Fraile depression illustrates the signature of sustained wind erosion in a tectonically deformed region. The southern Puna Plateau is thus one of Earth's best examples of sustained wind erosion and a potential analogue for tectonically deformed regions on other planetary surfaces dominated by aeolian processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP23C2270M
- Keywords:
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- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 1625 Geomorphology and weathering;
- GLOBAL CHANGE;
- 5210 Planetary atmospheres;
- clouds;
- and hazes;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 5415 Erosion and weathering;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS