The study areas of this PhD thesis are located in the Peruvian and Argentinean Andean Back-Arc in South America. The thesis focuses on two major themes: firstly, on contractional thick-skinned tectonics (and related processes, regarding interplay and linkage of different structural styles); secondly, on multi-scale structural data integration and the quantification of uncertainty in kinematic restoration through forward modeling. Key scientific questions of this PhD thesis relate to the following: What controls the deformation styles in the Andean Back-Arc? How did the fractures in igneous rocks (hosted in thick-skinned structures) evolve in the greater tectonic context? How can uncertainty in kinematic restoration be quantified better?
Data from numerous different sources was integrated and assessed. The data sources used herein, include 2D and 3D seismic data, well data, surface geology, satellite imagery, digital terrain data, earthquake focal mechanisms, drill core data and gravity-magnetics data. For the Santiago and Pachitea Basins (Peru), the analysis resulted in revised structural styles, improved structural architecture, new data on structural timing, new shortening amounts, new slip rates and an improved understanding of the interplay of different structural styles with particular emphasis on the impact of salt tectonics. For the Neuquén Basin (Argentina), a new evolutionary fracture model in oil producing igneous intrusions (sills), including improved reservoir characterization, was developed. For the Malargüe Anticline, also located in the Neuquén Basin, a novel workflow was developed, to quantify uncertainty quantification in kinematic restoration through forward modeling.
In summary, highly variable tectonic response mechanisms are observed in the Andean Back-Arc. However, the impact of the mechanical stratigraphy appears to be more important and widespread than anticipated. Thick-skinned growth (with varying influence of salt tectonics) triggers thin-skinned thrusts. Alternating stress fields in the Back-Arc can explain complex fracture systems in brittle igneous rocks, where cooling fractures are overprinted by subsequent tectonic shearing motion. A newly developed forward modeling workflow allows for improved uncertainty quantification of thick-skinned contractional structures. This new workflow has various implications and should be tested by future researchers with various parameters simultaneously (e.g. through numerical modeling) and should be tested in other tectonic settings around the world, such as e.g. extensional or strike-slip settings.
