Facilities & Software

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.

(U-Th)/He Thermochronology

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%.

Fission Track Thermochronology Laboratory

 

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 Isotope Laboratory

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.

High Performance Computing Laboratory

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.

Terrestrial Remote Sensing for Active Tectonics & Surface Processes

 

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.

Computer Models & Data

We use a variety of 1D, 2D, and 3D numerical models to assist in the interpretation of erosion and sedimentation rate data collected in our laboratories. Many of the models we use are developed "in house" while others are developed as part of collaborative efforts with scientists around the world.

The figure shows a result from a 3-D thermo-kinematic model. The top surface in the figure is the topography of the Waddington region of the Coast Mountains, British Columbia. The lower two surfaces are the apatite (U-Th)/He and fission track closure isosurfaces beneath the topography. Models like this one are frequently used in our group to aid in the quantitative interpretation of low-temperature thermochronometer data. Important information that can be gained by integrating these models with data include evaluation of the magnitude and rates of erosion and the kinematic and structural evolution of active mountain ranges. The field work and sample collection/analysis are integral parts of our modeling efforts.


The below figure shows a result from a coupled atmospheric, surface process, and kinematic model. The model predicts erosion rates and topographic evolution for a 150 km wide, and 400 km long mountain range that has a uniform vertical uplift rate. This model is unique in that the precipitation rate across the range (colors draped over topography) is predicted from a physically based atmospheric model. The precipitation field is fully coupled and dependent on how the topography evolves. Models like this one are used in our group to better understand how climate, and tectonics interact and influence topographic evolution and long term erosion rates in mountains. We test our models of different field areas with a variety of different data types, including low-temperature thermochronometers, cosmogenic isotopes, and short-lived nuclides. However, we still have a lot we can learn about climate, tectonics and topography from just simple, well designed numerical modeling studies.

Paleoclimate modeling is now a regular component in our analysis of orogen evolution. We use global and regional general circulation models to quantify how climate may have varied as an orogens topography evolves. This approach is particularly useful for understanding how past precipitation and erosion rates may have differed from modern rates. It is also crucial for understanding how biologic controls on landscape evolution may have changed through time.

The below figure shows a palinspastic restoration of the northern Bolivian fold and thrust belt (Modified from McQuarrie, 2000) where we have conducted a thermochronometry and erosion study. We integrate balanced cross sections with thermochronometry and numerical modeling to better understand the kinematic and erosional history of active mountain ranges. Through this integration of techniques we hope to better understand the relative roles, and significance, of climate and tectonics on the evolution of active mountain ranges.

 

We acknowledge the kind donation by Petroleum Experts Ltd of 10 Educational Institution licences for the 3D-modelling software "Move". The commercial equivalent of the software donation is £1,334,160.00.