Unravelling the lithospheric-scale thermal field of the North Patagonian Massif plateau (Argentina) and its relations to
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ORIGINAL PAPER
Unravelling the lithospheric‑scale thermal field of the North Patagonian Massif plateau (Argentina) and its relations to the topographic evolution of the area Maria Laura Gomez Dacal1 · Magdalena Scheck‑Wenderoth1,2 · Eugenio Aragón3,4 · Judith Bott1 · Mauro Cacace1 · Claudia Tocho3,5 Received: 31 March 2020 / Accepted: 26 October 2020 © The Author(s) 2020
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 lithosphericscale 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. Keywords Thermal modelling · North Patagonian Massif plateau · Topography · Isostasy · Geodynamics
Introduction
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00531-020-01953-2) contains supplementary material, which is available to authorized users. * Maria Laura Gomez Dacal lauragd@gfz‑potsdam.de 1
Helmholtz-Zentrum Potsdam. Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany
2
RWTH Aachen Universität, Fakultät Georessourcen Materialtechnik, Aachen, Germany
3
Universidad Nacional de La Plata, La Plata, Argentina
4
Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
5
Comisión de Investigaciones Científicas CIC, Buenos Aires, Argentina
The North Patagonian Massif (NPM) is located in the backarc of the Southern Andes in central Argentina. It includes a plateau of an average altitude of 1200 m a.s.l. (meters above sea level; Coira et
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