High Voltage Pulsed Power Fragmentation System

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A fundamental step in many geochemical and geological analyses is fragmentation, or disaggregation, of rocks into their constitutive components for analysis of individual minerals, grain size variations, or other constituents (e.g. fossils). Unfortunately, conventional techniques such as jaw crushing are time consuming and often lead to low sample recovery. However, new technological advances such as pulsed power fragmentation provide a superior way to circumvent this problem. In this proposal, a new departmentally accessible core piece of equipment is requested for the recently constructed ‘Geo- und Umweltforschungszentrum’ (GUZ, ~21,000 m2) at the University of Tübingen. This equipment will replace traditional fragmentation instruments (jaw crushers) and provide higher sample throughput and yield, increase sample quality, and eliminates carcinogenic silicate dust production. High voltage pulsed power fragmentation (or electrical fragmentation) works for a large variety of composite materials including typical rock types (e.g. granite, gneiss, sandstone). The fragmentation and liberation of components is obtained by high voltage discharges generated between two electrodes. The material to be disaggregated is brought in-between the electrodes in a water-filled vessel. The discharge travels between the electrodes along grain boundaries and liberates individual grains without breaking them. From this process, the original grain-size of the composite material is preserved and because the process is conducted within water, silicate dust liberation does not occur.Rock fragmentation and mineral/fossil liberation is the basis for a variety of scientific methods in the geosciences and is also useful in other fields since any cohesive composite material can be disintegrated with electrical fragmentation. Within the GUZ and the Geoscience department a large number of researchers within geology, geochemistry, sedimentology, mineralogy, petrology and paleontology will benefit from this equipment. The main user of the electrical fragmentation system is the Earth System Dynamics Research Group (ESD-RG) at the University of Tübingen, consisting of ~40 people. The group investigates hypotheses centered around how plate tectonic, Earth surface, atmospheric, and biologic processes interact to determine the form and evolution of Earth's topography over geologic timescales. We do this using a variety of geochemical, high-performance computing, and remote sensing techniques. A key aspect of our research is in the innovative application of geo- and thermochronological techniques (e.g., U-Pb, (U-Th)/He and fission track dating, cosmogenic isotopes) to date geologic events and constrain the rate at which different tectonic and surface processes occur. These analytical techniques, when combined with state-of-the-science modeling techniques, allow the determination of spatial and temporal variations in erosion, deformation, and paleo topography.