IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
. Evidence of Quaternary tectonics along Río Grande valley, southern Malargüe fold and thrust belt, Mendoza, Argentina
Autor/es:
FENNELL, LUCAS; SAGRIPANTI, LUCÍA; COLAVITTO, BRUNO; FOLGUERA, ANDRÉS; COSTA, CARLOS
Revista:
GEOMORPHOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2019
ISSN:
0169-555X
Resumen:
The Malargüe fold and thrust belt is developed in the Argentinian Andes between 34º and 37º S,through the tectonic inversion of Upper Triassic and Lower Jurassic depocenters of the Neuquén Basin,with an uplift history since the Cretaceous. Evidence of Quaternary deformation has been described inthe northern part of it (34-34.5°S), potentially coeval to neotectonic activity along the eastern edge ofSan Rafael block. To the south, compressional and extensional structures active during the Quaternarywere found in the Dorso de los Chihuidos along the Agrio fold and thrust belt front (37.5-38°S).Contrastingly, the southern segment of the Malargüe fold and thrust belt between these two areas withdescribed neotectonic activity is partially covered by Quaternary products of the Payún Matrú volcanicfield, that may hide evidence of recent deformation. In this 300 km gap of neotectonic information, thelandscape imprint of two individual structures aligned in the mountain front through the Río Grandevalley was analyzed. New evidence of neotectonic deformation were recognized, in particular over thewestern slope of the Cara Cura range, expressed by faulting and folding of Quaternary deposits andACCEPTED MANUSCRIPTACCEPTED MANUSCRIPTlava flows. An 40Ar/39Ar age from a deformed lava flow at the flanks of an anticline in the foothills ofthe Cara Cura range may suggest at least an upper Pleistocene compressional tectonic activity.Longitudinal river profile analysis revealed anomalies that show some correlation with the neotectonicstructures described, especially knickpoints and concavity index changes. Meanwhile normalizedsteepness index values showed a moderate response to recent deformation. A proposed schematicgeomorphic evolution for this segment of Río Grande river is discussed to put the neotectonic activityinto the context of landscape formation. All together this evidence supports the idea of an active frontthrough the Río Grande valley during the Quaternary, coetaneous to an active broken foreland to theeast in the southern Central Andes.