Authors: Guillermo Fuentes (presenter), Universidad Santo Tomás, Incaic Exploration; Rodrigo Muñoz, Taypi Geohidroconsultores Limitada; Sebastián Perroud, Incaic Exploration, Universidad de Chile; Fernando Martínez, Universidad Católica del Norte; Walter Garrido, Universidad Santo Tomás, Incaic Exploration
Presentation is in Spanish.
Recent advances in the knowledge of the forearc tectonic and structural evolution elucidate the strong control of the pre-orogenic structures in the accommodation of the Andean shortening. As have been shown in others orogens, the choose of the structural style can lead a difference of up to an order of magnitude in shortening estimations. Particularly in the Western Andean Mountain Front (WAMF), at 21°S, depending on the structure style selected, contrasting tectonic models have been proposed (crustal structures) to explain the Andean orogenesis. In order to assess the structural style and tectonic evolution, between 20°30’-21°15’S, we present a detailed 2D seismic interpretation calibrated by well and drill-hole data, and rock outcrops. Also, we perform isopach map and restored geological sections. The main results of this contribution reveal partially inverted graben and half-graben arrays formed by Jurassic to Early Cretaceous extension and subsequently underwent contraction which led the basin inversion at least since the Upper Cretaceous, developing hanging and footwall short-cut structures. Inverted syn-rift isopach map gives us the chance to propose lateral continuation of main structures and identify along strike variations, as tip points, polarity changes and accommodation zones, showing a pseudo-3D structural configuration for the WAMF. Most of the shortening estimations were close to 3 km, despite of along strike variations on main inverted graben and half-graben structures. Partially inverted graben and half-graben arrays, its evolution and along strike variations must be consider in future tectonic models to better understand the main Andean structures.
Bio
Guillermo Fuentes, Universidad Santo Tomás, Incaic Exploration
Guillermo graduated on geology and got his PhD on structural geology and tectonics in the University of Chile. He has participated with the AMTC in two geology national maps for the Geological National Survey (SERNAGOMIN) and has been consultor in economic structural geology for major companies as Antofagasta Minerals, as well he has lead generative mineral exploration projects for covered zones in the north of Chile. He has been research fellow at Universidad Santo Tomás and academic in others universities in Chile.
He currently is Assistant Professor at Universidad Santo Tomás, where he is responsible for field and structural geology courses, head of applied structural geology and geotectonics group at the university. He also works as Exploration Manager at Incaic Exploration SpA.