Forschungsthemen
COOLER: Climatic controls on erosion rates and relief of mountain belts
The ERC-funded research project COOLER aims to quantify the feedbacks between tectonic processes in the lithosphere and climatic processes in the atmosphere. Advancing our understanding of these couplings requires the development of tools that record erosion rates and relief changes with higher spatial and temporal resolution than the current state-of-the-art, and integrating the newly obtained data into next-generation numerical models that link observed erosion-rate and relief histories to potential driving mechanisms. Within the COOLER project, we will: (1) develop new high-resolution thermochronology by setting up a world-leading 4He/3He laboratory; (2) develop numerical modelling tools that incorporate the latest insights in kinetics of thermochronological systems and make sample-specific predictions; (3) couple these tools to glacial landscape-evolution models, enabling modelling of real landscapes with real thermochronology data as constraints; and (4) study potential feedbacks between glacial erosion and tectonic deformation in carefully selected field areas. The new high-resolution data will be integrated and extrapolated to quantitatively assess the impact of late Cenozoic climate change on erosion rates. Integration and analysis of the data will lead to novel insights into the two-way coupling of glacial erosion and tectonics, as well as latitudinal trends in glacial erosion patterns. (COOLER project webpage)
Plateauentwicklung und Klima in den südlichen Zentralanden
Nach Tibet ist das Anden-Altiplano/Puna-Plateau die zweitgrößte Plateauprovinz der Erde. Prozesse, die mit der Entwicklung des Plateaus verbunden sind, haben die tektonische Entwicklung der Plateauränder und der angrenzenden Regionen im zerbrochenen Andenvorland und im Falten- und Überschiebungsgürtel des subandinen Vorlandes nachhaltig beeinflusst. In unseren Studien analysieren wir (1) die Rolle langfristiger klimatischer Veränderungen auf die Plateaubildung in den südlichen Zentralanden Boliviens und Argentiniens; (2) bestimmen den Beginn der humiden vs. ariden Klimabedingungen entlang der östlichen Anden; (3) bewerten die Rolle tektonischer und klimatischer Einflüsse bei der Verfüllung und Ausräumung intermontaner Sedimentbecken; und (4) bestimmen Paläo-Höhen anhand von Sauerstoff- und Wasserstoffisotopen, die an Paläoböden und vulkanischem Glas in känozoischen Vulkanascheschichten gemessen wurden.
Exhumation, topography and the interplay between tectonics and climate: insights from thermochronology and surface-process studies (Himalaya, Tien Shan and Pamir)
The topography reflects tectonism at variuos length and time scales and the overprint of multiple climate-driven processes and related effects in changes of erosional efficiency. On long time scales, focused precipitation and mass removal may even introduce changes to the tectonic stresses in the orogen and affect the locus of tectonic activity. While many of these issues are beginning to be understood now, numerous open questions remain. For example, it is still not very well known what the necessary time scales are to generate topographic changes that develop into efficient orographic barriers. Importantly, it has not been been very well established, which kind of processes of erosion are most efficient, and which climatic and erosional thresholds exist to significantly alter a tectonically active system. Furthermore, it is poorly known, which role transient sediment storage in intermontane basins plays in triggering or abandoning fault activity, how such sediment fills are stored in such basins, and how they influence foreland sedimentation, once connectivity with the foreland has been re-established. Feedbacks between these processes apparently exist, but the time scales at which changes may be efficiently introduced into the system are vaguely known. Therefore, the recognition of positive feedback mechanisms between the effects of sustained precipitation patterns, vegetative cover, weathering, and tectonic activity in a mountain belt are first-order research topics that merit further consideration. In our projects in the Himalaya, Tien Shan, and Pamir we address these issues and strive to unravel the complex relationships between various surface processes and tectonic evolution.
Forearc segmentation and the earthquake cycle in South-Central Chile
Forearc regions are among the most tectonically active settings worldwide, often subject to pronounced tectonic uplift and subsidence. Surface uplift, subsidence history, and the composite landscapes that evolve in such regions may thus provide important insight into the factors that govern the geodynamic and structural evolution of these dynamic environments. The forearc of South-Central Chile is characterized by different seismotectonic and geomorphic segments, documenting a distinct spatiotemporal tectonic evolution that may encapsulate important information concerning crustal behavior during the seismic cycle. In this study our goals are focused on (1) defining the long-term style and chronology of tectonic processes in the forearc region; (2) estimating deformation rates over the seismic cycle and the Quaternary Period in the southern sector of the Valdivia 1960 earthquake segment; (3) obtaining a paleoseismic record of subduction earthquakes in this region; and (4) integrating deformation rates and paleoseismic records to obtain a strain partitioning budget and explore its influence on modulating earthquake recurrence and magnitude.
Marine terraces of the last interglacial period along the Pacific coast of South America (1° N–40° S)
Tectonically active coasts are dynamic environments characterized by the presence of multiple marine terraces formed by the combined effects of wave-erosion, tectonic uplift, and sea-level oscillations at glacial-cycle timescales. Well-preserved erosional terraces from the last interglacial sea-level highstand are ideal marker horizons for reconstructing past sea-level positions and calculating vertical displacement rates. We carried out an almost continuous mapping of the last interglacial marine terrace along ~5,000 km of the western coast of South America between 1° N and 40° S. We used quantitatively replicable approaches constrained by published terrace-age estimates to ultimately compare elevations and patterns of uplifted terraces with tectonic and climatic parameters in order to evaluate the controlling mechanisms for the formation and preservation of marine terraces, and crustal deformation. Uncertainties were estimated on the basis of measurement errors and the distance from referencing points. Overall, our results indicate a median elevation of 30.1 m, which would imply a median uplift rate of 0.22 m/ka averaged over the past ~125 ka. The patterns of terrace elevation and uplift rate display high-amplitude (~100–200 m) and long-wavelength (~102 km) structures at the Manta Peninsula (Ecuador), the San Juan de Marcona area (central Peru), and the Arauco Peninsula (south-central Chile). Medium-wavelength structures occur at the Mejillones Peninsula and Topocalma in Chile, while short-wavelength (< 10 km) features are for instance located near Los Vilos, Valparaíso, and Carranza, Chile. We interpret the long-wavelength deformation to be controlled by deep-seated processes at the plate interface such as the subduction of major bathymetric anomalies like the Nazca and Carnegie ridges. In contrast, short-wavelength deformation may be primarily controlled by sources in the upper plate such as crustal faulting, which, however, may also be associated with the subduction of topographically less pronounced bathymetric anomalies. Latitudinal differences in climate additionally control the formation and preservation of marine terraces. Based on our synopsis we propose that increasing wave height and tidal range result in enhanced erosion and morphologically well-defined marine terraces in south-central Chile. Our study emphasizes the importance of using systematic measurements and uniform, quantitative methodologies to characterize and correctly interpret marine terraces at regional scales, especially if they are used to unravel tectonic and climatic forcing mechanisms of their formation. This database is an integral part of the World Atlas of Last Interglacial Shorelines (WALIS), published online at http://doi.org/10.5281/zenodo.4309748 (Freisleben et al., 2020).
Effects of climate warming on debris flow activity and sediment supply in high mountain regions
Climate plays a critical role in the dynamics of surface processes and sediment transfer in mountain catchments. However, the differential response of mountain catchments to modern climate change suggests that, in addition to the increase in water runoff and sediment availability that follows ice melt, other parameters may control the dynamics of sediment production and transfer. These are not only of interest to the scientific community, but also to local and regional authorities to develop sustainable management plans in vulnerable mountain regions. In this project, two end-member valleys in the Italian Alps are being studied to understand the response of mountain catchments to global warming and to assess the role that glacial melting, permafrost degradation, and increases in extreme precipitation may have on sediment supply and debris flow activity. This project aims to analyze: 1) variations in the sediment transport dynamics of mountain catchments by means of cosmogenic nuclide methods; 2) the chronology of debris-flow events through dendrochronology; and 3) debris flows and rockfall trigger areas by time series analysis of orthophotos – allowing the assessment of the effects of temperature and extreme precipitation in glaciated and deglaciated catchments on sediment release and transport to ultimately explore possible hazardous future scenarios. (Deutsche Forschungsgemeinschaft (DFG) - Project# 399435624)
LIFE: Linking lake-level variations, surface deformation, and seismogenesis in the Dead Sea
The Dead Sea is the deepest continental basin on Earth and constitutes a region of protracted subsidence and seismic activity. However, instead of subsidence, this area is currently experiencing rapid uplift accompanied with accelerated lake level decline, suggesting complex patterns of vertical displacement (e.g., isostatic rebound) over time. In addition, the abundance of paleoseismic records shows that variations in the recurrence time of earthquakes roughly coincide with lake-level changes at millennial timescales, suggesting a close relationship between lake-level fluctuations and seismogenesis. In this project, we seek to unravel the link between climatic and tectonic forcing mechanisms on millennial time scales in the Dead Sea by taking advantage of the outstanding exposure of emerged lakeshores. The results of this project will be important in terms of possible seismic scenarios related to global climate change and engineering projects to alter the water volume of the Dead Sea. (Deutsche Forschungsgemeinschaft (DFG) - Project# 397011549)
LEAP: Linking structural Evolution with QuAternary landscape evolution and deformation in the western Himalaya: structural segmentation and implications for seismogenesis in Pakistan
The regional distribution of major earthquakes (Mw≥ 7) along the Himalayan arc indicates that seismicity is associated with locked seismotectonic segments of the north dipping Main Himalayan Thrust (MHT). In the tectonically active western Himalayan orogen region of Pakistan, however, similar-sized earthquakes appear to be confined to three major, obliquely-striking transpressional transfer zones. The seismotectonic of these transfer zones is poorly understood because of a lack of data about the spatiotemporal structural evolution and the deformation rates associated with this portion of the orogen in Pakistan. This proposal aims to address this shortcoming in one of the transfer zones and adjoining areas by (a) modeling structural evolution at a million-year time scale, (b) identifying zones of active deformation and defining rates of Quaternary deformation across active structures, and (c) bridging the deformation rates at different temporal scales. The expected results will provide a better understanding of the structural control and deformation mechanism on seismogenesis in specific seismotectonic segments of the mountain range that are prone to deformation and susceptible to seismogenic hazard. (Deutsche Forschungsgemeinschaft (DFG) - Project# 510220130)
AR-Ansätze in der beruflichen Weiterbildung von Verwaltungsmitarbeitern des Katastrophenschutzes und der Zivilen Sicherheit (oKat-SIM)
oKat-SIM steht für optimierte Katastrophenbewältigung mittels Simulation. Zu diesem BMBF-geförderten Verbundprojekt hat sich ein interdisziplinäres Team aus den Geo- und Kognitions-wissenschaften der Universität Potsdam sowie aus den Bereichen Multimediale und interaktive Systeme der Universität Lübeck und Neue Medien der Filmuniversität Babelsberg sowie der UP Transfer GmbH an der Universität Potsdam zusammen-geschlossen. Der Hintergrund von oKat-SIM ist, Augmented Reality (AR) in der beruflichen Weiterbildung für Katastrophenschutz und zivile Sicherheit einzusetzen, mit dem Ziel, Führungskräfte in Verwaltung und Landesbehörden für die Krisensituation fachlich und methodisch zu schulen. Dazu will man Großschadenslagen visualisieren und Krisenstabsszenarien in einer 3D-Umgebung simulieren. Diese 3D-Umgebung ist mobil und integriert AR-Brillen mittels Simulationsserver und Steuerungskontrolle. AR erlaubt einerseits die Visualisierung realistischer Vor-Ort-Situationen und andererseits das kooperative Handeln des Krisenstabs in möglichen Echtzeit-Szenarien. Dadurch wird die Vielfalt von Handlungsoptionen direkt spürbar und die Tragweite der daraus resultierenden Entscheidungen sichtbar. (oKat-SIM)