Crystal-Chemical, Thermodynamic and Physical Properties of Garnet in the System-Grossular-Andradite-Uvarovite-Knorringite: An Experimental and Theoretical Investigation

Project Details

Description

1) To begin, the garnet end-members uvarovite, andradite and Mg-knorringite will be synthesized at high pressures. They will be carefully characterized using optical microscopy, electron microprobe, X-ray powder diffraction and IR and 57Fe Mössbauer spectroscopy.
2) A series of grossular-andradite solid solutions will be synthesized and carefully characterized.
3) We will make relaxation Cp measurements between 2 K and 300 K on synthetic end-member andradite, uvarovite and knorringite and nearly end-member natural crystals of the first two. Magnetic ordering related to Fe3+ and Cr3+ and Cschottky effects and their contribution to Cp and S will investigated. We also want to compare the Cp behavior between natural and synthetic crystals (see work on grossular - Dachs et al. 2012). The S for all phases will be determined.
4) We will make DSC Cp measurements between 300 K and 900 K on synthetic andradite, uvarovite and knorringite in order to obtain a complete description of Cp behavior from 0 to 900 K.
5) We will make low-temperature relaxation Cp measurements between 2 K and 300 K and DSC measurement from 300 to 900 K on grossular-andradite solid solutions to determine their ΔCpmix/ΔSmix. An analysis of their magnetic and electronic behavior will be made as well.
6) We will make 27Al and 29Si MAS NMR and 57Fe Mössbauer spectroscopic measurements on a number of natural and synthetic Fe-containing grossular crystals to investigate SRO involving Al and Fe3+.
Short titleCrystal-Chemical, Thermodynamic and Physical Properties of Garnet
StatusFinished
Effective start/end date1/10/1330/06/17

Fields of Science and Technology Classification 2002

  • 1508 Mineralogy

Fields of Science and Technology Classification 2012 (6-digit codes)

  • 105116 Mineralogy

Fields of Science and Technology Classification 2012

  • 105 Geosciences