Fault inversion vs new thrust generation: a case study in the Malargüe fold-and-thrust belt, Andes of Argentina

MESCUA, J. Y GIAMBIAGI, L.

JOURNAL OF STRUCTURAL GEOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2012 vol. 35 p. 51 - 63

0191-8141

We conclude that the inversion of major Mesozoic normal faults during the Andean orogeny might have contributed significantly to uplift and deformation in the evolution of the Malargüe FTB. In the sectors of the fold-and-thrust belt where geological evidences show the presence of important pre-existing faults related to the Mesozoic extensional episode, inversion must be taken into account in structural models of Andean deformation. As we have shown, given the orientation of these structures, the possible physical characteristics of fault planes and host rocks, and the Andean stress field, the Mesozoic normal faults are suitable for inversion. Features particular to each case, such as the kinematic evolution of specific structures, will determine the mode of inversion, for example if only the re-use of the pre-existing fault takes place of if shortcut or by-pass faults develop, or may locally inhibit inversion. But for the general cases, we have shown that inversion is expected to be the rule rather than the exception for the Malargüe fold-and-thrust belt. Our results can be extended to other sectors of the Andes in which pre-existing crustal discontinuities with similar orientations are present and to other mountain belts with similar characteristics.