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PRISE   Analytical Techniques

 

We specialise in high quality major, minor and trace element and isotopic analysis and interpretation of all diamond indicator minerals. Some specific examples of our capabilities are described below.

Potential clients are welcome to make contact and discuss ideas for projects at any stage.

Cr-spinel

Existing techniques for discrimination of Cr-spinel from kimberlitic or lamproitic sources from other, non-diamond related sources are inadequate. RSES scientists have developed a new technique based on discriminant analysis using major, minor and trace elements (measured by electronprobe microanalysis and Laser Ablation ICPMS). This technique can discriminate Cr-spinel grains of crustal and shallow mantle origin from those of deep mantle origin with >90% accuracy.

A pdf (500kB) describing the technique in some detail can be downloaded here.

Garnet

We can perform high quality WDS electronprobe microanalysis using the RSES Cameca SX-100 for major and minor elements, and trace element analysis by LA-ICPMS (including Ni, Ga, Sc, Co, V, P, Na, Sr, Y, Zr, Nb, Hf, REE and others) with high precision and detection limits in the ppb range.

We can classify garnets using modern classification schemes, perform Ni in garnet thermometry and use REE patterns and other trace element characteristics to examine the grains metasomatic history.

Cr-diopside

Using precise major and minor element compositions of Cr-diopside grains determined by WDS electronprobe, we can determine the grains' provenance (deep mantle vs. shallow mantle or other sources) and calculate pressure-temperature information for deep mantle derived Cr-diopside, using the Nimis and Taylor (2000) technique.

Zircon and Perovskite

Using SHRIMP we can perform precise single grain U-Pb geochronology on zircon, monazite, rutile and perovskite, for direct dating of kimberlites or for provenance studies.

We can also use SHRIMP to measure Ti contents of zircon, and apply the newly developed Ti in zircon thermometer (Watson and Harrison 2005). This may be useful for discriminating high temperature mantle derived zircon megacrysts sometimes transported by kimberlite, from lower temperature magmatic or metamorphic zircons derived from the crust.

We can also use LA-ICPMS to determine the full range of trace element abundances in zircon, and LA-MC-ICPMS (Neptune) to determine Lu-Hf isotopic compositions, for provenance information.