@article{BorchertWilkeSchmidtetal.2009,
  author    = {Borchert, Manuela and Wilke, Max and Schmidt, Christian and Rickers, Karen},
  title     = {Partitioning and equilibration of Rb and Sr between silicate melts and aqueous fluids},
  issn      = {0009-2541},
  doi       = {10.1016/j.chemgeo.2008.10.019},
  year      = {2009},
  abstract  = {Trace element concentrations in aqueous fluids in equilibrium with haplogranitic melt were determined in situ at elevated P-T conditions using hydrothermal diamond-anvil cells and synchrotron-radiation XRF microanalyses. Time- resolved analyses showed that the Rb and Sr concentrations in the fluids became constant in less than 2000 s at all temperatures (500 to 780 degrees C). Although fluid-melt equilibration was very rapid, the change in the concentration of both elements in the fluid with temperature was fairly small (a slight increase for Rb and a slight decrease for Sr). This permitted partitioning data for Rb and Sr between haplogranitic melt and H2O or NaCl+KCl+HCl aqueous solutions at 750 degrees C and 200 to 700 MPa to be obtained from EMP analyses of the quenched melt and the in situ SR-XRF analyses of the equilibrated fluid. The resulting D-Rb(f/m) and D-Sr(f/m) were 0.01 +/- 0.002 and 0.006 +/- 0.001 for water as starting fluid, and increased to 0.47 +/- 0.08 and 0.23 +/- 0.03 for 3.56 m (NaCl+KCl)+0.04 in HCl at pressures of 224 to 360 MPa. In the experiments with H2O as starting fluid, the partition coefficients increased with pressure, i.e. D- Rb(f/m) from 0.01 +/- 0.002 to 0.22 +/- 0.02 and D-Sr(f/m) from 0.006 0.001 to 0.02 +/- 0.005 with a change in pressure from 360 to 700 MPa. At pressures to 360 MPa, the Rb/Sr ratio in the fluid was found to be independent of the initial salt concentration (Rb/Sr = 1.45 +/- 0.6). This ratio increased to 7.89 +/- 1.95 at 700 MPa in experiments with chloride free fluids, which indicates different changes in the Rb and Sr speciation with pressure.},
  language  = {en}
}
@article{SchmitzMoellerWilkeetal.2009,
  author    = {Schmitz, Sylvia and Moeller, Andreas and Wilke, Max and Malzer, Wolfgang and Kanngiesser, Birgit and Bousquet, Romain and Berger, Alfons and Schefer, Senecio},
  title     = {Chemical U-Th-Pb dating of monazite by 3D-Micro X-ray fluorescence analysis with synchrotron radiation},
  issn      = {0935-1221},
  doi       = {10.1127/0935-1221/2009/0021-1964},
  year      = {2009},
  abstract  = {A confocal set-up for three-dimensional (3D) micro X-ray fluorescence (micro-XRF) was used at the mySpot beamline at BESSY II, which allows compositional depth profiling for various applications. We present results obtained with a confocal 3D micro-XRF set-up for chemical age dating using the U, Th and Pb concentrations of monazite within rock thin sections. The probing volume was determined to be approximately 21 x 21 x 24 mu m(3) for W-L alpha using an excitation energy of 19 keV. The relative detection limits particularly for Pb are below 10 ppm (for Counting times},
  language  = {en}
}