Raman-Spektroskopie für anorganische und organische Feststoffanalyse, Geothermobarometrie und Flüssigkeits- einschlussuntersuchungen.

The analysis of inorganic and organic solid matter in natural scientific research is commonly performed with a number of devices based on X-ray techniques (XRD, XRF), inductively coupled plasma mass spectrometry (ICP) or electron microprobe (EMP). Most of these techniques yield very precise chemical analyses of the investigated specimen but do not reveal any information on its properties (e.g., crystallinity and crystal system, organic group etc.). Furthermore, the majority of these techniques are considerably limited concerning their spatial resolution or the type of elements, which can be analyzed. The electron microprobe, which is the only instrument performing a non-destructive analysis of very small particles (< 5 ?m), is either limited to elements heavier than oxygen and not at all able to analyze organic matter. A high-tech approach to identify inorganic and organic phases is Raman spectroscopy, which allows non-destructive analysis based on spectra resulting from inelastic scattering of the sample molecules activated by monochromatic laser light. Raman spectroscopy can be applied to solid, liquid and gaseous phases and thus covers the whole range of matter in geosciences as well as soil biology and archeology. We therefore decided to purchase a Bruker SENTERRA confocal Raman spectrometer, which works with multiple wavelengths (two lasers with 532 nm and 785 nm) and has a very high spectral resolution of <3cm-1 and a spatial resolution of 1 ?m. Five groups of the Department of Environmental Sciences of the University of Basel take part in this project. 1.) The Petrology/Mineralogy Group (Leander Franz & Christian de Capitani) will use the Raman spectrometer in the framework of the existing SNF project NF-200021-113399/1/1 (Multiple high- and ultrahigh-pressure orogenies in the Qinling Mountains: boundary conditions permitting their formation and exhumation) for phase identification and geothermobarometry. 2.) The Fluid Inclusion Group (Josef Mullis) will identify the chemical character of the fluid inclusions in metamorphic minerals (blueschist facies and greenschist facies minerals from veins). 3.) The Fission Track Group (Alexandre Kounov and Meinert Rahn) plan to study the extent of metamictization within minerals containing fission tracks in order to further develop Raman-based techniques in low-temperature thermochronology. 4.) The Soil Science and Terrestrial Biogeochemistry Group (Christine Alewell & Franz Conen) will use the Raman spectrometer for identification and mapping of inorganic components and organic matter in soils. 5.) The Archaeology Group (Jörg Schibler and Philippe Rentzel) will use the Raman spectrometer for archaeometrical studies in the framework of analysis of ceramics, determination of pigments and studies on the provenance of prehistoric raw materials. A sixth group from the Geosciences Department of the Natural History Museum Basel (André Puschnig) would benefit from the analytical possibilities of the Raman spectrometer to perform non-destructive identifications of numerous valuable samples. Finally, the Raman spectrometer will also serve as a teaching tool for master and PhD students. Quick access to and the knowledge about the possibilities of such modern analytical equipment is an integral part of scientific education as well as research. Hence, this equipment also fulfills the needs of an innovative curriculum at the Department of Environmental Sciences at the University of Basel.