Internally consistent thermodynamic dataset for tourmalines

• Antragsteller: Privatdozent Dr. Klaus-Dieter Grevel
• Fachliche Zuordnung: Mineralogie, Petrologie und Geochemie
• Förderung: Förderung von 2012 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 226299000

Our main goal is to derive an internally consistent thermodynamic data set for minerals of the tourmaline group. Initially, we have chosen the tourmalines dravite (NaMg3Al6(BO3)3Si6O18(OH)4) and olenite (Na0.5-1Al3Al6(BO3)3Si6O18(O,OH)4) to test our approach. Later, the investigations will be extended to Ca- and Fe-bearing tourmalines. The proposed project consists of four principal parts, which are described below:1. We want to synthesize and characterize phase-pure olenite and dravite. Further minerals of the tourmaline group shall be synthesized afterwards. The synthesis shall be done by use of piston-cylinder devices and the hydrothermal lab at Ruhr-University Bochum, and GeoForschungsZentrum Potsdam, respectively.2. Detailed calorimetric investigations (heat capacity, enthalpy of formation, standard entropy) are planned in the calorimetry labs at Jena University (enthalpy of formation) and Salzburg (heat capacity (Cp), standard entropy by low temperature Cp-measurements using a PPMS® system).3. Some additional compressibility and thermal expansion data of different tourmalines (P-V-T data) will be obtained by in-situ X-ray diffraction (XRD) experiments using a MAX-80 apparatus at Hasylab, Desy, Hamburg.4. Finally, all data obtained will be used as phase property constraints for extending the internally consistent thermodynamic database of Grevel (2004) by mathematical programming. The necessary phase equilibria constraints will be taken from the literature.

• DFG-Verfahren: Sachbeihilfen
• Beteiligte Person: Professor Dr. Juraj Majzlan, Ph.D.