Marco tectónico y su correlación con la hidrología en las cuencas de Tongoy y Limari, Chile

Abstract

The tectonic model between the Tongoy Bay area and the west part of Limarí River basin allows connecting the morphological structure of the underground bedrock with the current and historical hydrology of Limarí River. Such morphology was obtained from the analysis and interpretation of 668 gravimetric stations distributed in 28 profiles. The information is supported by the results of several seismic profiles already conducted in the area. 

The result of the gravimetric analysis shows a very irregular bedrock morphology, where two underground basins of considerable dimensions separated by a gap in the bedrock stand out. The first basin is located in the north area of the survey zone, Seca/Pachingo creek area, which main axis is north-south strike with an approximate depth of 550 m to the bedrock; end the second basin is located south- west from the survey area, Barraza/Socos zone, with the main axis of east-west strike and approximate depth of 500 m to the bedrock. 

According to the existing and available background information, the hypothesis states that Limarí River, in ancient times, run into the Pacific Ocean through Tongoy Bay, east from Puerto Aldea site. The hypothesis is also supported by drilling results conducted in nearby Quebrada Seca and Cerrillos de Tamaya sites, indicating the existence of sedimentary materials characteristic from north-strike hydric flows.