Uplift analysis on a pericratonic region: An example in the Sierras de Córdoba (29°-34°S), Argentina

CANELO, HORACIO N.; FEDERICO MIGUEL DAVILA; NOBILE, J.C,

GEOMORPHOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 p. 81 - 98

0169-555X

The Sierras de Córdoba (Argentina) is a mountain belt located in the most distal (pericratonic) part of the SouthCentral Andean foreland, in the easternmost end of the Sierras Pampeanas (Pampean ranges) broken foreland.Although this region is considered an excellent example for settings where basement thrusting generates reliefand intermontane basin systems, hundreds of kilometers away from the Cordilleran front, the driving mechanisms and main controls on topography are still poorly understood. Given that the landscape, and particularlythe rivers, react to changes in climate and tectonics on timescales between 103 and 106 yrs, we used DEMbased morphometry (elevation patterns, local relief, and analysis of 242 longitudinal stream profiles) to evaluatethe main controls on modern topography. We focus on the morphologies of the main streams and their tributaries using metrics of the channel concavity and normalized channel steepness index (ksn). The distributionof local relief, concavity and ksn values was compared with the present-day topography, tectonic structures,rock-type and modern rainfall patterns. The stream longitudinal profiles show homogeneous concavities andksn background values, with some local anomalies. Local structures (east and west vergent thrusts) in the Sierrasde Córdoba seem to be the most fundamental controls on the formation of these anomalies, slope-breakknickpoints as well as deep incision (high local relief). This suggests localized and accelerated rock uplift rates,which produce localized increases in the gradient along the longitudinal stream profile. It is important to noticethat the highest ksn values were reported on the eastern range flanks, coincident with the highest values of meanannual rainfall. However, high ksn values appear to be maintained even with greater rainfall. Our study providesnew insights on the Neogene Sierra de Córdoba uplift evolution, which will assist future sampling and modelling(cosmogenic nuclides analysis, thermochronology and GPS analysis).