Controles de la geometría de la subducción en la estructura térmica de cuencas sedimentarias de la región de subducción plana Pampeana.

COLLO, G.; EZPELETA M.; DÁVILA, F. M.; GIMENEZ M.; SOLER S.; MARTINA F.; AVILA P.; SANCHEZ NASSIF F.; CALEGARI. R., LOVECCHIO J.P. Y SCHIUMA M.

Congreso; XX Congreso Geológico Argentino; 2017

Asociación Geológica Argentina

Controls of the subduction geometry in the thermal structure of sedimentary basins of the Pampean subduction region. Flat-slab segments are considered refrigerated areas given that the asthenospheric wedge shifts hundreds of kilometers away from the trench, and the flat and subducting plate acts as a thermal insulator. Although lithospheric- scale thermal analysis abound, studies on the thermal history of sedimentary basins affected by flat-slab are scarce. In this contribution, we present a temperature data compilation from more than 60 oil wells within the Pampean flat-slab segment in the south-central Andes and the transitional zones to normal subduction to the north and south. The geothermal gradient data are correlated with basin basal heat flow, Curie point depths. Our modelling shows that sedimentation changes are not sufficient to explain the variations in the geothermal gradient, and that basal heat flux variations are required to reproduce the reported values. The coldest basins develop over the flatslab or craton ward regions, whereas the highest temperatures on areas where the slab plunges. This is likely related with that the flat slab geometry and the lithospheric structure, which would be conditioning the thermal state within the upper crust and particularly the sedimentary basins.