Multiple geophysical methods examining neotectonic blind structures in the Maradona valley, Central Precordillera (Argentina)

KLINGER, FEDERICO LINCE; VARGAS, NICOLÁS; LARA, GABRIELA; PERUCCA, LAURA; ROJO, GUILLERMO; LEIVA, FLAVIA

TECTONOPHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 712-713 p. 634 - 642

0040-1951

A high-resolution superficial geophysical study was carried out in an area of the retroarc region of the Andesmountains, located in the southwest of San Juan Province (31°45′ S, 68°50′W), Central Precordillera of Argentina.The main objectives of this study were to confirm the presence of blind neotectonic structures and characterizethemby observing variations inmagnetic susceptibility, density and p-wave velocities. Geological evidence demonstratesthe existence of a neotectonic fault scarps affecting Quaternary alluvial deposits in eastern piedmont ofde Las Osamentas range, in addition to direct observation of the cinematic of this feature in several natural exposures.The Maradona valley is characterized by the imbricated eastern-vergenceMaradona Fault Systemthat upliftsNeogene sedimentary rocks (Albarracín Formation) over Quaternary (Late Pleistocene-Holocene) alluvialdeposits. The combined application of different geophysical methods has allowed the characterization of ablind fault geometry also identified on a natural exposure. The magnetic data added to the gravimetric model,and its integration with a seismic profile clearly shows the existence of an anomalous zone, interpreted asuplifted blocks of Miocene sedimentary rocks of Formation Albarracín displaced over Quaternary deposits. Theapplication and development of different geophysical methods, together with geological studies allow to significantlyimproving the knowledge of an area affected by Quaternary tectonic activity. Finally, this multidisciplinarystudy, applied in active blind structures is very relevant for future seismic hazard analysis on areas locatedvery close to populated centers.