Deformation and stratigraphic models of the Bolivian and Argentinean sub-Andean system: Evolution of knowledge and current trends

HERNÁNDEZ, ROBERTO; HERNÁNDEZ, JUAN; DALENZ FARJAT, ALEJANDRA; ALVAREZ, LUIS; CRISTALLINI ERNESTO OSVALDO; TOMEZZOLI, RENATA N.; ROSALES, ADOLFO; GALVARRO JAIME

Petroleum basins and hydrocarbon potential of the Andes of Peru and Bolivia

American Association of Petroleum Geologists

Lugar: Boulder ; Año: 2018; p. 1 - 26

The sub-Andean system through Argentina and Bolivia is composed of a fold-and-thrust beltdeveloped from 9 Ma until today, as a result of an east-northeast-verging compressive stressfield. Depending on the area evaluated, thin- or thick-skinned deformation characterizes thestructural style throughout this orogenic system.The differences in structural styles depend on variables such as the sedimentary columninvolved, internal facies and thickness changes, detachment level features, climatic influence,and the presence of inherited extensional and compressional structures. The existing balancedstructural cross-sections sometimes present difficulties for solving the rate and chronology ofthe deformation.The aim of this chapter is to present suitable new deformation models integrating distinctkinematic characteristics and to analyze the variables involved in the southern sub-Andeanthin-skinned fold-and-thrust belt.The structural framework proposed for the southern sub-Andean system in Bolivia andnorthwestern Argentina is based in the identification of four rheological levels. Levels 1 and 3,with a shale-dominated composition (Kirusillas and Los Monos Formations, respectively),are deformed as a weak isotropic material and can be simulated using Trishear kinematicmodeling. On the other hand, rheological levels 2 and 4 (Tarabuco?Santa Rosa?Icla?HuamampampaFormations and Carboniferous?Cenozoic interval, respectively), with a sand/shalealternating composition, are structured as a strongly heterogeneous interval responding tothe compressive stress field with parallel folding. A simple shear kinematic model could beused to simulate this deformation. This behavior has been tested as a feasible model for thedeep structure in significant oil/gas fields in Argentina and Bolivia.