Latest SCI publications
The Local Last Glacial Maximum along the Patagonian Andes: a composite geographic, geochronologic and modeling approach
Research project (§ 26 & § 27)
Duration : 2017-11-15 - 2021-11-14
In order to understand the mechanisms underlying the climate cycles that have punctuated the Quaternary period, we need to unravel the geographical extent and test for interhemispheric phasing of glacial events. New glacier records from southern Patagonia suggest that maximum glacial extent during the last glacial cycle occurred sometime during the Marine Isotope Stage (MIS) 3. In this context, new data from the southern mid-latitudes in Patagonia, and New Zealand, reaffirm the important unsolved question regarding the timing, structure and duration of the local glacial maximum in the southern mid-latitudes: When did the local glacial maximum occur in the region? Why have only scattered sites in Patagonia revealed glacial expansion during MIS 3? Is the new glacier evidence from these scattered southern Patagonian sites a local anomaly or have we not yet completely unraveled the complete configuration of the southern Andean LGM? In this regard, the main goal of the research project is to determine the timing of the local last glacial maximum along the Patagonian Andes (43-55ºS). In order to accomplish this objective the proposed research includes the following interconnected approaches: glacial geomorphology, glacial stratigraphy, geochronology and glacial modeling. By selecting sites along a latitudinal transect we aim to include the latitudinal as well as the local factors that may control the Patagonian glaciation. We address this issue by applying a 3D Parallel Ice Sheet Model (PISM), constrained by precise mapping and well-dated glacial landforms. We will apply 10Be exposure-cosmogenic dating on boulders resting on moraines, OSL and 10Be dating in glaciofluvial sediments. We expect our composite approach will allow us to bracket the timing of the local LGM extent in Patagonia and thereby test for regional, hemispherical and global phasing of maximum glaciation during the last ice age.
Research project (§ 26 & § 27)
Duration : 2014-12-01 - 2016-11-30
Currently Vienna's subway line U1 is being extended towards the south. From the station Reumannplatz, the planned line runs towards the south following a course below Favoritenstrasse towards the new stations Troststraße and Altes Landgut. The line runs up to 25m below surface and cuts through a succession of geological units. The base is formed by sediments from the Neogene which are covered by sediments of the Quaternary. These sediments are associated with fluvial terraces, which were predominantly formed by the Danube in the past. Currently a relative chronology for the formation of these terraces which form the landscape surface of Vienna exists, however, a numerical (absolute) chronology is still missing. With access to undisturbed sediments usually being very limited within the cityscyape of Vienna, the construction of the U1 offers a unique opportunity to take samples for numerical dating along a transect through a complex sedimentary succession of the Quaternary, and to promote new insight into the lansdscape history of Vienna. By applying physical dating methods, depositional ages can be determined for the sediments. In the project two independent dating methods will be applied: optically stimulated luminescence (OSL) dating, and burial age dating using cosmogenic nuclides. The aim of the project is to establish a terrace chronology for the cityscape of Vienna which will for the first time be based on results from numerical dating techniques. This may also contribute to the question if and when a tectonical displacement of the terrace bodies may have happened throughout the Quaternary.
Research project (§ 26 & § 27)
Duration : 2014-05-01 - 2017-06-30
Catastrophic granular and debris flows occur in many mountain areas all over the world. Snow avalanches, rock or rock-ice avalanches, debris flows, lahars and pyroclastic flows are only some examples. An adequate management of the risk related to these phenomena requires a detailed and reliable analysis of the mechanisms involved in such processes. Even though much work has been done on this subject, and a number of physically-based models with a varying degree of complexity do exist, some problems still remain unsolved: (1) Flow over arbitrary topography, the role of viscous pore fluid or two-phase nature of flow, and particle and/or fluid entrainment have not yet been accounted for in an appropriate way. (2) Until now, no successful attempts have been made to build easy-to-handle Open Source applications of these complex models, which would be essential to make them available to a broader group of users in universities and public services. This project offers an effective, innovative and unified solution to these two problems. It is therefore concerned with rapid geophysical mass flows, including avalanches and real two-phase debris flows, from a known initiation zone through the flow path along natural mountain topography into the deposition zone. For a given amount of mass and its distribution in the initiation zone, we are interested in the motion and geometric deformation along the track down the arbitrary topography, including the processes of erosion and deposition of mass along the track and the ultimate distribution of the deposited mass. This will also include the effect of dynamically evolving pore fluid pressure and/or evolution of the solid and the fluid components. An equally important focus shall be put onto the development of a user-friendly and freely accessible application of the developed model. This application will build upon the GIS software GRASS, which is available as an Open Source product under the GNU General Public License. The new software will be evaluated using physical model tests and well-documented mass flow events. These tests will cover a broad range of processes and process chains including debris flows, debris avalanches and avalanches of snow or rocks.