INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Transtensional tectonics induced by oblique reactivation of previous lithospheric anisotropies during the Late Triassic to Early Jurassic rifting in the Neuquén basin: Insights from analog models
FLORENCIA BECHIS; ERNESTO OSVALDO CRISTALLINI; LAURA BEATRIZ GIAMBIAGI; DANIEL LEONARDO YAGUPSKY; CECILIA GUZMÁN; VÍCTOR HUGO GARCÍA
JOURNAL OF GEODYNAMICS
PERGAMON-ELSEVIER SCIENCE LTD
Lugar: Amsterdam; Año: 2014 vol. 79 p. 1 - 17
The goal of this study was to determine the main factors that controlled the kinematicevolution and the structural architecture developed during the Late Triassic to EarlyJurassic rifting that led to the opening of the Neuquén basin in the southwestern sector ofGondwana. We carried out a series of analog models to simulate an extensional systemwith a bent geometry similar to the northeastern border of the basin. In differentexperiments, we varied the extension direction between NNE (N10°E) and NE (N45°E) orientations, inducing rift systems with different degree of obliquity in each sector of theextended area. We compared the kinematic evolution and the final structural architectureobserved in the experiments with data from two selected representative areas of the basin:1) the Atuel depocenter, situated in the northern Andean sector, and 2) the Entre Lomasarea, situated in the northeastern Neuquén Embayment. In both cases, the good matchbetween the field and subsurface data and the results of the analog models supports a NNEorientation of the regional extension (N30°E to N20°E) during the synrift stage. Ourexperimental results suggest that lithospheric weakness zones of NNW to NW trend couldhave controlled and localized the extension in the Neuquén basin. These previousanisotropies were linked to the sutures and rheological contrasts generated during thecollision of terranes against the southwestern margin of Gondwana during the Paleozoic, aswell as further modifications of the thermo-mechanical state of the lithosphere during theLate Paleozoic to Early Mesozoic evolution.