Surface Processes

Topic Surface Processes

Fault systems in the broken foreland of NW Argentina are associated with isolated seismicity, deformation, and uplift, and they pose a major problem in understanding the spatiotemporal characteristics of individual earthquakes and long-term deformation patterns. Range uplift in these environments is highly disparate in time and space, without a clear deformation front as in the foreland fold-and-thrust belt to the north. Some ranges constitute large anticlines that have formed over blind thrusts, such as the growing anticlines west of the town of Salta.

The principal aim of these two Postdoc projects is to determine how climate shifts and variability influence the dynamics of surface processes and affect landscape evolution over various timescales. Given the demonstrated sensitivity of landscape denudation rates to precipitation along the steep slopes of the eastern margin of the Andean Plateau 1, we hypothesize that the generation of thick late Pleistocene sedimentary fill terraces is linked to wetter climate conditions, and possibly also to changes in the variability of rainfall.

The spatial architecture of sedimentary facies in a basin exert a fundamental control over the patterns of fluid flow and determines the regional distribution of possible reservoirs and seal units. The distribution of sedimentary facies can be predicted to some extent by sequence stratigraphic theories. These models offer a conceptual framework to extrapolate facies distribution at a regional scale in 2D, ranging from continental to basinal.

A sink to source approach in the central Andes, to test the hypothesis that the amount of Cretaceous exhumation is related to the magnitude of Cenozoic deformation in the adjacent basin and inversely related to the amount of Cenozoic exhumation.

The key question which this project aims to answer is how tectonic processes such as mountain-range uplift affect atmospheric circulation patterns and enforce subsequent hydrological changes. The NW Argentine Andes are an ideal location to study these processes, due to unique and characteristic circulations patterns associated with the South American Low Level Jet (SALLJ) as part of the SAMS, which were established as a consequence of the topographic growth of the Andean orogen.

The PhD project focuses on the analysis of rock glaciers and rock slides feeding the central Andean sediment cascade on two study areas in the Central Andes (Rio Atuel) near Mendoza and Desert Andes (Sierra Famatina) near La Rioja. The aim is to see how spatial pattern, topographic characteristics and climate parameters control the episodic and gradual release of sediment into the drainage network.

Extreme rainfall events fundamentally impact erosion and deposition. The combination of the South American Monsoon System (SAMS) and high topography of the Central Andes constitutes the most important drivers for the highly asymmetric distribution of rainfall.