Thermo-mechanical analysis of the Andean lithosphere over the Chilean-Pampean flat-slab region

LINCE KLINGER, FEDERICO; GIANNI, GUIDO M.; SÁNCHEZ, MARCOS A.; FOLGUERA, ANDRÉS; GARCÍA, HÉCTOR P.A.; MARTINEZ, MYRIAM P.; WEIDMANN, M. CECILIA; ARIZA, JUAN P.; LINCE KLINGER, FEDERICO; GIANNI, GUIDO M.; SÁNCHEZ, MARCOS A.; FOLGUERA, ANDRÉS; GARCÍA, HÉCTOR P.A.; MARTINEZ, MYRIAM P.; WEIDMANN, M. CECILIA; ARIZA, JUAN P.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017

0895-9811

Flat subduction segments are generally related to cold lithospheric zones, which suggest low Heat flowvalues and therefore a deeper Curie isotherm. In this study we perform a geophysical analysis by usinghigh - resolution magnetic data, obtaining shallower Curie point depths through the Chilean-Pampeanflat-slab zone. Then using temperatures from borehole data and Curie Point Depths, we performed aHeat Flow map which indicates the existence of mean to high thermal anomalies across the Chilean -Pampean flat-slab. These results were contrasted with Elastic Thickness map (Te) obtained from theEigen-6C4 gravity model. Low Te values acquired indicate zones with weak mechanical behavior incorrespondence to thermal anomalous zones. This spatial correlation suggests that the local high thermalanomalies are conditioning the mechanical behavior of the lithosphere in the study area and the locationsof geothermal sources. Overall, our results indicate that the thermal structure of the flat-slabsegment is more heterogeneous than previously thought. This has implications for evolution, maturityand fluid circulation in foreland basins of the Main and Frontal cordilleras and the Precordillera thrustbelts. Finally, further studies will allow improving our database as well as extending our understandingof the thermal structure of the Chilean-Pampean flat-slab.