Tectonics

Topic Tectonics

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 Plateau1, 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 Chaco-Paraná Basin is located east of the Sierras Pampeanas and the Santa Barbara System. The basin has been a depocenter since the early Paleozoic and has been under strong influence of the Andean orogeny since the Cenozoic. In the basin, a gradient of different deformation styles developed due to the Andean orogeny. This project aims to construct a data-consistent, integrated three-dimensional structural model of the Chaco-Paraná Basin on a lithospheric scale.

The evolution of the inter-mountain Salta basin is related to the evolution of the Central Andes. An intracontinental rift was formed by extensional processes and subsequently filled by up to 5500 m sediments from the Neocomian to the Paleogene intercalated by minor volumes of magmatic rocks. This complex constitutes the Salta group. Paleoenvironmental analysis reveals depositional history controlled by tectonic and climatic changes.

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.

In this project we will investigate large and medium-magnitude earthquakes using waveform analysis of historical and modern seismograms for event location, magnitude, and depth as well as focal mechanisms and source-time function. Historical earthquakes recorded at analog stations worldwide (primarily recorded on paper or film) since the beginning of the last century can be digitized and analyzed with advanced methods to better constrain their characteristics.