Controles precuyanos en la estructura de la Cuenca Neuquina

Abstract

Anintegrated map of the Upper Triassic - Lower Jurassic structures (Precuyano)developed in the eastern region of the Neuquén Basin is presented. Theprincipal grabens, half-grabens, faults and transference zones developed southof Río Colorado are mapped based on 2D and 3D seismic information and previouspublished works. The general direction of Upper Triassic-Lower Jurassic normalfaults is NW. However, two distinct populations can be differentiated. Thefirst one (NW) has directions higher than azimuth 130°, and in general,accommodates the major and deepest grabens and half-grabens (e.g. Entre Lomasand Estancia Vieja). The directions of the second population faults (WNW) arelower than azimuth 110° and in general are related to small and shallower troughs(e.g. Loma la Lata, Agua de Cajón, Lindero Atravesado, Bandurria, etc.). Theinteraction between both fault populations is not easy to see, tough, in somesectors it can be seen that the second (WNW) cuts the first (NW). Distributedover the whole region there are Upper Jurassic - Cretacic normal faults. Thesefaults are nucleated over the oldest precuyano (Tr-J) faults and over thehinges of the half-grabens. In this work, these normal faults are explained asthe result of the tension related to the differential subsidence of the grabensand half-graben infill. These J-K normal faults have general NW directions andare developed parallel to the NW precuyano faults population and en echelonover the WNW population.