Natural examples of regional-scale structures from the southern Central Andes and Patagonian Andes

The use of natural examples as analogues to interpret seismic and well data always brings us useful and important information for forecasting and modeling structures at depth. In this chapter, we present field examples of a wide variety of structures from the eastern slope of the southern Central Andes and the Patagonian Andes. Examples vary from major thrust systems from Andean fold-and-thrust belts exemplifying the relationship between thrust movement and sedimentation, the complex internal structure of a major fault system, the relationship between a basement-involved thrust and cannibalization of foreland basin deposits, active tectonics along thrust fronts, and the superimposition of structures from different tectonic events. Outcrops provide a source of prior knowledge that helps with understanding and more coherent interpretation of subsurface data. Their study shed light into the internal structure of a fault system, which is critical for the understanding of migration and trapping of fluids along and across main faults, as well as the style of deformation, that is, thin- versus thick-skinned deformation, and the geometry of blind faults responsible for the fault-propagation folding.