INVESTIGADORES
ALVAREZ PONTORIERO Orlando
artículos
Título:
The origin of the depressions interrupting the eastern Sierra Pampeanas broken foreland, explained by localized crustal extension through the juan Fernández ridge path, using gravimetric data
Autor/es:
GIMENEZ, MARIO; VILLEGAS A, RAQUEL J.; RICHARTE, DANIEL; LINCE KINGER, FEDERICO; ALVAREZ, ORLANDO; NACIF, SILVINA; FOLGUERA, ANDRÉS
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2023 vol. 122
ISSN:
0895-9811
Resumen:
The Salinas Grandes and Salina de Ambargasta salt pans are located in the Eastern Sierras Pampeanas in the Pampean broken foreland zone, a product of the Chilean-Pampean flat subduction zone. This region constitutes an anomalously flat morphology of 350 × 150 km and occupies an extensive area in a northeast-southwestdirection.These flat depressions abruptly interrupt the eastern Sierras Pampeanas morphology, burying the structure beneath Late Cenozoic-Quaternary deposits of theAndean orogenic front. We obtained from a previous model in spherical harmonics, the geometry of the Moho observing a lower crustal attenuation below the saltpan areas, which is maximum towards the north of the Salina de Ambargasta. From the Bouguer anomaly, calculated by unifying data from different sources, and itsresidual anomaly, we calculated the analytical signal to adjust the gravimetric anomalys wavelength, which shows that this flat morphology follows NE to NNEgravity minima. Werner deconvolution and localized Euler deconvolution calculated from the residual Bouguer anomaly indicate that the anomalous masses arelocated above 15 km depth, by the wavelengths of the anomalies, presumably indicating the differential uplift of high-density rocks placed in the lower and mid-crust, following the measured crustal attenuations. Additionally, these solutions show that this NE depression is segmented by NNW structures perpendicular tothe main trough. Crustal thickness attenuation is interpreted as related to the track of the Juan Fernandez Ridge beneath the eastern Pampean broken foreland sector,based on plate kinematic reconstructions. As depicted in recently released tomographic data, its tearing and related asthenospheric upwelling could have promotedlithospheric localized extension, explaining the Salinas Grandes-Ambargasta depressions that are segmenting the eastern Sierras Pampeanas at the Andean orogenicfront