Three-dimensional audio-magnetotelluric characterization of the geothermal area in Tucumán basin, Argentin

LILIANA GUEVARA; POMPOSIELLO, MARIA CRISTINA; A. FAVETTO

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2019 vol. 97 p. 1 - 9

0895-9811

The main aim of this work is to relate the geoelectrical units defined by the 3D model to the geological units in<br />the southeast of the Tucumán plain, where geothermal manifestations are shown by artesian wells with temperatures<br />between 38 °C and 50 °C. Two field campaigns involving 41 audio-magnetotelluric sites in the frequency<br />range 100,000 to 10 Hz were carried on. Some sites are located near the wells, where the depth from<br />which they bring water to the surface is known. The 3D model allows us to describe characteristics of the<br />electrical resistivity of the different sedimentary formations as well as to correlate it with the structural features<br />present in the region of study. The most remarkable feature of the final model is the high conductivity of the<br />deepest geoelectrical unit associated with a formation of marine origin in which the presence of illite and<br />montmorillonite has been determined. In addition, as some information from the wells is available for the layer<br />taken advantage of, it was possible to validate the resistivity determined by the model with that obtained with<br />Archie´s law, finding correspondence.