Abstract

ARIZA, Juan P et al. Geology and geophysics from the northern part of the sierra de Villa Corral (31º08' LS- 69º24' LW), western precordillera of San Juan. Geoacta [online]. 2015, vol.40, n.2, pp.52-59. ISSN 1852-7744.

In this paper the geology and geophysics of northern part of the Sierra de Villa Corral is presented. The study area is located in the Western Precordillera of San Juan (31º08'LS - 69º24'LW). Here are compared the structural and stratigraphic features of a NE-SW cross-section with aeromagnetic data and remote sensing. Techniques of band ratios were applied to the Landsat 7 (ETM+) images. The general structure of the Sierra de Villa Corral is defined by a syncline fold with axis dipping toward SE. The mentioned fold is segmented by two systems of thrusts (Andean and Pre-Andean). The thrusts can be grouped according to the strike and dip direction of fault planes, relative age of deformation and vergence. Pre-Andean thrusts are oriented NW-SE and dip toward NE with a top to SW vergence, while the Andean thrusts are oriented N-S, fault planes are dipping toward W with a top to the E vergence. Lower Paleozoic and Neogene units are involved in both sets of thrusts, which shows that all structures have undergone tectonic activations during the Andean orogeny. Finally, the design of the residual magnetic anomalies map, analytic signal map, Tilt and Tilt gradient, are closely related to the structural and stratigraphic aspects observed in surface. Thus, it is posible infer the arrangement of the structures and the geological units in the subsurface. The analytic signal profile shows that the main magnetic contrasts are produced by major thrusts. Moreover, the analytical signal allowed to adjust the distribution of units in the subsurface according to the relative displacement of the fault blocks.

Keywords : Magnetic Anomaly; Remote sensing; Structural geology; Lower Paleozoic.

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