Along-strike structural variations in the Southern Patagonian Andes: Insights from physical modeling

LIKERMAN, J.; BURLANDO FARÍAS, J.F.; CRISTALLINI, E.O.; GHIGLIONE, M.C.

TECTONOPHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012

0040-1951

The Southern Patagonian Andes between 48º and 53º SL offers a unique opportunity to study theresults of orogenic growth superimposed over a previously rifted region. In this sector the northern Austral or Magallanes basin was affected by late to middle Jurassic extension followed by Late Cretaceous to Neogene tectonic compression. The resultant fold-thrust belt displays significant along-strike variations in width and lateral position of the structural domains that may be reflecting a first order control of the Jurassic extensional depocenters, as proposed in previous works. This hypothesis is tested using a series of scaled sandbox analogue models involving the positive inversion of two adjacent depocenters with different extensional rates accommodated by a transfer fault. The correlation between structures in the Southern Patagonian Andes and the features in the model have important first order similarities supporting the theory of a positively inverted extensional basin with a previous history of southward increase in extension. Moreover structural cross-section analyzed from field and seismic data have a geometry that is consistent with serial cross sections resulting from the models.