Utilización de imágenes SIR-C en el estudio de lineamientos en las unidades volcánicas Cretácicas y Terciarias de la región de Coquimbo (Chile):el sector de Quebrada Marquesa.

Resum

The remote sensing Radar images offer to the geologist an outstanding tool allowing a better definition of the estructural features of a region. The flights of the space shuttle Endevour in 1994 allowed experimentation with a brand-new radar scanner: the SIR-C (Shuttle Imaging Radar, C generation). Images of the Coquimbo region (Chile) kindly offered to the authors by the JPL (Jet Propulsion Laboratory, Pasadena, USA) have allowed definition of major structural trends, within a region where lower Cretaceous to lower Tertiary volcanic Formations account for most of the geology of the area. The linear features correspond to regional faults: 1) N W to NNW , 2) N-S, 3) N N E to NE, 4) WNW, and 5) WSW. Only the two first trends were known before this study. Sub-circular structures have been interpreted as eroded calderas. The caldera-type structure are clearly visible in the raw images, while three newly defined fault trends (NNE, W N W and WSW) w ere observed in derivative images obtained by data processing (by ERDAS IMAGINE). Both the NNW trend and caldera-type structure seem to be related to mineralizing process. Structural blocks observed in the Marquesa Gulch area may be the result of the intersection of the NNE and ENE trends