Geomorphology of Talacasto alluvial fan, Precordillera of San Juan, Argentina

Abstract

We present a 1:50,000 geomorphological map of the Talacasto river alluvial fan (93 km 2 ), located in the Central Andean Precordillera of Argentina. The aim of this map is to identify and classify dynamic and potentially destructive geomorphological processes such as gully erosion, headward erosion, concentrated erosion, laminar erosion and similar features that are present in an alluvial fan, so as to identify unstable sectors for public infrastructure. This map is the result of combining remote sensing data, aerial photographs analysis and fieldwork. Landforms and active geomorphological processes are identified, classified and illustrated for this Quaternary alluvial fan. Four Quaternary landscape subunits were classified, taking into account morphogenetic characteristics and erosional processes such as:(1) Exhumed and erosional landforms inducted by neotectonic activity; (2) Alluvial landforms;(3) Polygenetic landforms covered in glacis; and (4) Playa lake landforms. The presence of desert pavements and salt-hardened subsoil formations contributes to the generation and transmission of surface runoff during summer heavy rains, causing alluvial hazards and damages in routes and roads.

Análisis morfotectónico y gravimétrico en un valle intermontano de la Precordillera Central de San Juan, Argentina

“…Los cambios de procedencia registrados en la edad del zircón detrítico sugirieron un acortamiento inicial en la Cordillera Frontal que coincidió con el cambio de acumulación eólica a fluvial en la cuenca de antepaís adyacente, durante el Mioceno temprano (24-17 Ma) y consideraron entre los 12 y 9 Ma, como la probable edad de exhumación inducida por el empuje y levantamiento de la Precordillera (Levina et al, 2014). Allis (2016), por su parte, analizó el piedemonte oriental de la sierra de la Crucecita e identificó estructuras con evidencia de actividad neotectónica, mientras Ocaña et al (2017) presentaron un mapa geomorfológico del abanico aluvial del río Talacasto e indicaron algunos procesos geomorfológicos dinámicos y potencialmente destructivos para la infraestructura pública.…”