Geodynamics

Topic Geodynamics

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 Cenozoic central Andes host orogen-parallel belts of magmatic-related ore deposits with contrasting metal associations (Fe, Cu-Au, vs. polymetallic, Sn-Ag). This project will investigate the role of magmas vs. hydrothermal fluids in metal transport and metallogenesis. There a close linkages to projects G3.5 and G4.1.

This project will investigate the primary source rocks for Sn (and Nb-Ta) and rare earth elements (REE) in the pre-Andean basement rocks (granites, pegmatites, metamorphic complexes) and the enrichment/mobilization processes related to chemical (hydrothermal alteration or weathering) and mechanical processes (ductile or brittle deformation in fractures and ductile shear zones). The investigation will focus on selected field occurrences of Palaeozoic granites, pegmatites, and their highly deformed metamorphic equivalents of the pre-Andean crustal basement, especially of the Salta Province.

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 Andean foreland demonstrates a pronounced N-S oriented differentiation in the style and magnitude of deformation and the nature of sedimentary basins. East of the Altiplano-Puna plateau and the Eastern Cordillera, a wedge-shaped, ~250-km-wide thin-skinned fold-and-thrust belt defines the eastern border of the orogen, which then transitions into the contiguous Chaco-Paraná foredeep.

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.