DEFORMATION AND STRATIGRAPHIC MODELS OF BOLIVIAN AND ARGENTINEAN SUBANDEAN. EVOLUTION OF KNOWLEDGE AND CURRENT TRENDS

ROBERTO M. HERNÁNDEZ; JUAN I. HERNANDEZ; ALEJANDRA DALENZ FARJAT; CRISTALLINI ERNESTO OSVALDO; ALVAREZ LUIS A. ; TOMEZZOLI RENATA NELA; ROSALES ADOLFO; GALVARRO JAIME S.

AAPG MEMOIR

American Association of Petroleum Geologists

Año: 2020

0271-8529

The Subandean system along Argentina and Bolivia conforms a fold and thrust belt developed from 9 Ma until today, due to an east-northeast verging compressive stress field. Depending on the area considered, thin or thick skinned deformation characterizes the structural style along this orogenic system.The differences in the structural styles depend on variables such as the sedimentary column involved, internal facies and thickness changes, detachment level features, climatic influence and the presence of inherited extensional and compressional structures. The existing structural balanced cross sections, in some cases, have problem to solve the rate and chronology of deformation.The aim of this paper is to present suitable new deformation models integrating distinct kinematic characteristics and analyzing the variables involved in the southern Subandean thin-skinned fold and thrust belt. The structural framework proposed for the southern Subandean in Bolivia and northwestern Argentina is based in the identification of 4 rheological levels. The levels 1 and 3, with a shaledominated composition (Kirusillas and Los Monos Formations, respectively), are deformed as a weak isotropic material and can be simulated using Trishear kinematic modeling. On the other hand, the rheological levels 2 and 4 (Tarabuco- Santa Rosa - Icla ? Huamampampa Formations and Carboniferous-Cenozoic interval, respectively), with a sand/shale alternating composition, are structured as a strongly heterogeneous interval answering to the compressive stress field with parallel folding. A simple shear kinematic modeling can be used to simulate this deformation. This behavior has been tested as a feasible modeling for the deep structure in important oil/gas fields in Argentina and Bolivia.