Document Type

Article

Publication Date

1979

Abstract

Apollo-Soyuz photographs of the Monte Desert in southeastern San Juan, Argentina, were used for a reconnaissance survey of large-scale desert landforms. The Apollo-Soyuz color photographs were helpful in distinguishing lineaments and probable faults, drainage patterns, rock types, and soil-tonal variations. These photographs were especially useful in studying the distribution of sand deposits and large-scale dune morphology, The photographs reveal that the physiographic setting of the study area is characterized by moun- tain-andnrolsón topography controlled mainly by faulting, Most of the lineaments detected on the Photographs appear to correspond to faults, and some of them may provide evidence of recent fault movement in the area. Typical topographic features include barren, dleeply dissected block mountains bordered by slopes of alluvial materials that descend to a flat-floored desert basin,The most prominent features on the desert floor are two dune fields. The larger field lies south of the lown of Vallecito and is approx- mately 1300 km²; the smaller dune field is hear the town of Marayes and is approximately 160 km², In the southern part of the V allecito dune fiekdl, Braa-size complex ridges display steep western Janks and gently sloping eastern Mlanks. These lidges are diagonally crossed by smaller linear dunes. In the central part, draa-size crescentic dunes with elongated horns abound; these horns may be affected by a seasonal cross wind called the zonda. The complex array of transverse, longitudinal, and oblique elements displayed by the Vallecito dunes cannot easily be explained. These patterns may be controlled by changes in climate, underlying and surrounding topography, wind regime, amount of sediment available, and grain-size characteristics. It is recommended that fieldwork be conducted to establish the roles of these factors in the formation of the complex Vallecito dunes.

Download

Share

COinS