The Earth System Dynamics research group maintains several different laboratories used to quantify interactions between the lithosphere, atmosphere, and biosphere at the Earth's surface. An overview of the laboratories completed and/or currently under construction is presented below. Most laboratory facilities and software are open to collaborators and/or for contract jobs. Interested parties should contact Todd Ehlers.
Low-temperature thermochronometers, such as apatite and zircon fission track and (U-Th)/He dating, provide important information about the cooling history of rocks near the Earth's surface. Rock cooling histories can be significantly influenced by erosion and topography. We use low-temperature thermochronology to quantify the deformation, erosion, and paleotopographic history of orogens. All facilities required for high-quality mineral separations are available in house.
The (U-Th)/He laboratory is now fully functional and generating data. Leica and Olympus high-end stereo and cross-polarized binocular microscopes are available for sample preparation. Following sample preparation, apatite and zircon samples are degassed using a Patterson instruments extraction line with a diode laser and quadrupole mass spectrometer. The system is fully automated. U, Th, and Sm are measured with an inductively coupled plasma mass spectrometer through collaborative partnerships. The Tuebingen (U-Th)/He lab reproduces the Durango age standard to within 5-6%.
The ESDynamics thermochronology lab has two Zeiss Axioskope fission track mircoscopes with a Dimitru FTstage 4.0 system (upgraded F/2009-W2010). Furthermore, a Zeiss M2M microscope with Autoscan software was recently installed and used for standard and fully automated track counting. All facilities are 'in house' required for sample preparation (grain mounts, polishing on a Struers Tegrapol system) and etching. We use the external dector method on apatite and zircon. Sample irradiations are done with thermal neutrons at the Garching reactor (Munich).
Cosmogenic isotopes are a powerful tool for quantifying erosion rates on time scales shorter (1000-10,000 yr) than thermochronometers are sensitive to. The ESDynamics research group has a cosmogenic isotope sample preparation laboratory for 10Be, 26Al, and 36Cl. Facilities include all equipment necessary for cleaning quartz including a 60 liter ultrasonic bath, 2 Franz magnetic separators, HF digestion fume hoods with large capacity hot plates, large capacity centrifuge, and a semi-clean lab for sample chemistry and target preparation. Cosmogenic isotope samples are measured at the AMS facilities at Purdue Univer (Prime Lab), ETH Zurich, Switzerland, and through new AMS facilities under development in Germany (Rossendorf). Renovation and modernization of laboratories for column chemistry is currently underway.
The ESDynamics group owns a Beowulf cluster group. Currently there are 360 processors with 12 GB RAM per processor available for the simulation of lithospheric and atmospheric processes. This cluster is used to simulate many different processes including the thermal and mechanical evolution of active orogens, glacial fluvial and hillslope processes in response to changing climate, tectonics and vegetation, crustal hydrologic processes, and modern- and paleo-climate using global and regional general circulation models. These facilities are connected via a high-speed network to the ESDynamics visualization and GIS laboratory. The cluster and GIS/modeling visualization laboratory share 360 TB of file space for data storage.
Light Detection And Ranging (LiDAR) is a well-established technology for three-dimensional measurement of surfaces. In the last decade both aerial and terrestrial, or ground based, LiDAR have grown in their use because they provide precise (cm scale) measurement of the Earth's surface and overlying biomass. Repeat LiDAR surveys of a region allow quantification of temporal changes in vegetation and mass movement. The ESDynamics has a research program for the repeated acquisition of LiDAR data in mountainous and glacial settings with an emphasis on developing geomorphic transport laws for glacial and periglacial settings. These settings are particularly sensitive to climate change and offer an exciting opportunity for studying the dynamics of mass transport at the Earth surface. The group owns an Optech ILRIS-LR laser scanner that is capable of scanning rock surfaces at 3-4 km (~80 % reflectance) and snow and ice at ~2 km distance (~80 % reflectance). Polyworks IM-Align and JRC Reconstructor software are used for data processing. Remote Sensing in the ESDynamics group also comprises terrestrial InSAR (Interferometric Synthetic Aperture Radar) scanning. Precise displacement measurments are possible with this technique by analyzing the phase difference between scans from the same scanning position. For this purpose, the group owns a GAMMA Portable Radar Interferometer (GPRI) unit with an operational range up to 4 km and a displacement sensitivity smaller than 2 mm. Processing of the InSAR data is done in the appendant command line program of GAMMA Remote Sensing Research and Consulting AG. Current studies apply this technique to mass movement, active tectonics and glaciology in Switzerland. Further projects using InSAR and LiDAR for the Alps and elsewhere in Europe are in the planning stages. This lab is located in Lothar Mayer Bau on Wilhelmstrasse 56, Tuebingen.