Transtensional tectonics induced by oblique reactivation of previouslithospheric anisotropies during the Late Triassic to Early Jurassicrifting in the Neuquén basin: Insights from analog models

BECHIS, F.; CRISTALLINI, ERNESTO; GIAMBIAGI, L.; YAGUPSKY, D.; GUZMAN, C.; GARCIA, VICTOR

JOURNAL OF GEODYNAMICS

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2014 p. 1 - 17

0264-3707

tThe goal of this study was to determine the main factors that controlled the kinematic evolution and thestructural architecture developed during the Late Triassic to Early Jurassic rifting that led to the openingof the Neuquén basin in the southwestern sector of Gondwana. We carried out a series of analog modelsto simulate an extensional system with a bent geometry similar to the northeastern border of the basin.In different experiments, we varied the extension direction between NNE (N10◦E) and NE (N45◦E) ori-entations, inducing rift systems with different degrees of obliquity in each sector of the extended area.We compared the kinematic evolution and the final structural architecture observed in the experimentswith data from two selected representative areas of the basin: (1) the Atuel depocenter, situated in thenorthern Andean sector, and (2) the Entre Lomas area, situated in the northeastern Neuquén Embayment.In both cases, the good match between the field and subsurface data and the results of the analog modelssupports a NNE orientation of the regional extension (N30◦E?N20◦E) during the synrift stage. Our exper-imental results suggest that lithospheric weakness zones of NNW to NW trend could have controlledand localized the extension in the Neuquén basin. These previous anisotropies were linked to the suturesand rheological contrasts generated during the collision of terranes against the southwestern margin ofGondwana during the Paleozoic, as well as further modifications of the thermo-mechanical state of thelithosphere during the Late Paleozoic to Early Mesozoic evolution.