Unravelling the lithospheric-scale thermal field of the North Patagonian Massif plateau (Argentina) and its relations to the topographic evolution of the area

Scheck-Wenderoth, Magdalena

Aragón, Eugenio
Bott, Judith

Cacace, Mauro

Tocho, Claudia
DOI: https://doi.org/10.1007/s00531-020-01953-2
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/10710
Scheck-Wenderoth, Magdalena; RWTH Aachen Universität, Fakultät Georessourcen Materialtechnik, Aachen, Germany
Aragón, Eugenio; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
Bott, Judith; Helmholtz-Zentrum Potsdam. Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany
Cacace, Mauro; Helmholtz-Zentrum Potsdam. Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany
Tocho, Claudia; Comisión de Investigaciones Científicas CIC, Buenos Aires, Argentina
Abstract
The North Patagonian Massif (NPM) area in Argentina includes a plateau of 1200 m a.s.l. (meters above sea level) average height, which is 500–700 m higher than its surrounding areas. The plateau shows no evidence of internal deformation, while the surrounding basins have been deformed during Cenozoic orogenic events. Previous works suggested that the plateau formation was caused by a lithospheric uplift event during the Paleogene. However, the causative processes responsible for the plateau origin and its current state remain speculative. To address some of these questions, we carried out 3D lithospheric-scale steady-state and transient thermal simulations of the NPM and its surroundings, as based on an existing 3D geological model of the area. Our results are indicative of a thicker and warmer lithosphere below the NPM plateau compared with its surroundings, suggesting that the plateau is still isostatically buoyant and thus explaining its present-day elevation. The transient thermal simulations agree with a heating event in the mantle during the Paleogene as the causative process leading to lithospheric uplift in the region and indicate that the thermo-mechanical effects of such an event would still be influencing the plateau evolution today. Although the elevation related to the heating would not be enough to reach the present plateau topography, we discuss other mechanisms, also connected with the mantle heating, that may have caused the observed relief. Lithosphere cooling in the plateau is ongoing, being delayed by the presence of a thick crust enriched in radiogenic minerals as compared to its sides, resulting in a thermal configuration that has yet to reach thermodynamic equilibrium.