Why use the SHRIMP?

The SHRIMP II is best suited to address isotopic problems where a non-destructive method is required, or where preservation of a spatial context is necessary. It is also an instrument for reconnaissance work where large numbers of lower precision analyses are needed (as in geological provenance studies).

Established techniques

• U-Th-Pb isotopic analysis of zircon
• U-Th-Pb isotopic analysis of monazite
• Ba, rare earth elements, Y, Hf, Th, U, Pb, P, Ca, Cr abundances in zircon
• Common Pb-isotopic analysis of most solids
• Os-isotopic analysis of Os-rich minerals

Typical Analytical Uncertainties (at 95% confidence level)

• ± 2-5% for elemental abundance ratios
• ± 0.05-1% for isotopic ratios
• ± 5-10% for elemental abundances

Techniques under development

• U-Th-Pb isotopic analysis of xenotime
• U-Th-Pb isotopic analysis of perovskite
• Sr-isotopic analysis of calcite

Samples

2.5 cm polished epoxy mounts (mineral grains or rock chips) and standard polished thin- or thick-sections

Future possibilities

• Sulphur isotopic analysis
• Oxygen isotopic analysis (a Cs-ion source is required, currently not available)

Detection limit

1-2 ppb for most elements in silicates

Spot sizes (diameter µm)

• ~2 x 3
• 4.5 x 6.5
• 7 x 9
• 9 x 12
• 13 x 18
• 17 x 23
• 26 x 36
• ~100