Cenozoic stratigraphy and structure in the Central Andes

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The central Andes, an integral part of the Cenozoic non-collisional orogenic belt parallel to the South American/Nazca plate boundary, is characterized by high elevation, high relief contrasts, and internally drained areas of low relief. The tectonic processes that led to the development of this orogen, which may have commenced during Cretaceous-Eocene time are well reflected in the foreland basin sequence in Bolivia. These sedimentary rocks represent a unique archive providing constraints on the geometry, rates, and history of orogenic and foreland basin evolution. Although thin-skinned horizontal shortening has been proposed as the main mechanism responsible for the Andean uplift in this region, the timing and magnitude of deformation and the effect of the pre-Mesozoic Izozog High on the Andean orogen make an unambiguous assessment of the tectonic evolution of the Andean foreland region difficult. These various uncertainties bring to question previous models for the late Cenozoic evolution of the southern central Andes. I propose in this project a multidisciplinary study that focuses to resolve the inconsistencies in (1) magnitude, timing, and geometry of the Andean deformation, (2) evolution of the Alto de Izozog structural high and its impact on foreland basin evolution, (3) Cenozoic sediment budget estimates and climate forcing parameters, thereby permitting reconstruction of the paleogeomophologic, paleoecologic, and tectonic evolution of the Andes. These objectives are best achieved through combining sedimentological, seismic stratigraphical, and geochronological analyses of the up to 7.5-km-thick Cenozoic strata in the Inter- and Subandean zones and the Chaco plain.