Distributary Drainage Systems in La Huerta Range, Western Pampean Ranges, San Juan, Argentina

COLOMBI, CARINA E.; SANTI MALNIS, PAULA; ROTHIS, L. MARTIN

SPRINGEREARTH

Springer Nature Switzerland

Año: 2019 p. 136 - 157

2194-5217

Transversal drainage systems in the southern portion of the Bermejo intermontane basin -SanJuan Argentina- is organized in five main rivers that reach the longitudinal Bermejo valley.Geomorphological and sedimentological survey of the Western piedmont of La Huerta rangeshows that there is a North-South trend change of drainage basin morphometry and faciesarchitecture. Facies distribution of the Las Chacras rivers, north portion of the piedmont, fits withthe classical alluvial fan model, with a divergent net of channels from the fan apex. In the middleportion of the piedmont and the Arenal and Puquial rivers, also alluvial fan facies present eolianinteraction with, triggering disconnection of mid fan facies from distal facies. In the southernportion of the piedmont drainage system flows parallel to axial drainage system (Bermejo river).Facies architecture is different from those observed in the northern portion. In the Pinche riverflows keep channelized until it distal portion in mid to high sinuosity channels that depositalternate and scroll bars. In the distal portion, main channel diverge in a distributary net ofchannels that develops a fan-shaped deposit characterized by terminal splays and eolian dunes.Facies distribution allow considering the El Pinche river as distributive fluvial system.