BASINS THERMAL STRUCTURE IN THE PAMPEAN FLAT SUBDUCTION ZONE

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

The making of the Chilean-Argentinean Andes

Springer

Año: 2018; p. 537 - 564

The first geothermal gradient map in the Pampean flat-slab segment of the south-Central Andesand the transitional zones to normal subduction (toward the north and south) is presented in thiscontribution. The new data is correlated basin-basal heat flow BHF estimated from petroleum explorationborehole data, Curie point depths (CPD) derived from aeromagnetic surveys and crustal and lithosphericthicknesses. Studies show that changes in the sedimentation histories of the analyzed basins is notsufficient to explain the recorded variations in the geothermal gradient, and changes in the basal heatfluxes are needed. The map distribution of geothermal gradient data and thermal modelling results in theArgentine flat-subduction segment evidence a quite good consistency and correlation among them.Regional variations, with the coldest basins over the flat-slab or towards cratonic areas and basins withthe highest temperatures developed on pluging-slab areas, show that the flat slab geometry as well as thelithospheric structure strongly affect the thermal state within the upper crust and particularly thesedimentary basins. Further studies will allow improving our database as well as the knowledge about thecontribution of the lithosphere radiogenic heat and the asthenospheric heat to the basins basal heat flow.