Sample Preparation

Epoxy grain mounts and thin sections

High precision quantitative analysis requires an optically flat, polished surface. Users may provide appropriately polished samples, either mounted in epoxy or as thin sections. Standard mount sizes are 1" (25mm) round mounts with maximum height of 1" (~1/2" is preferred), or standard U.S. thin sections; round 25 mm thin sections are also acceptable. Unusual and larger sizes can be accommodated but need to be approved in advance.

If you require assistance in fabricating polished thin sections or epoxy mounts, please consult U of U Sample Preparation Services .

The lab provides carbon coating of samples with our newly installed Denton Benchtop Turbo IV high vacuum evaporator. In order to analyze glass samples for oxygen, we require that each mount contain our standard obsidian so that the samples and standard have the identical thickness of carbon coating. We can supply the standard, or we can prepare the mount with the standard.

 

Preparation of tephra samples for mounting
If you are submitting tephra samples for mounting and analysis, they should be prepared prior to submission as follows:

1. If necessary, gently disaggregate the sample with mortar and pestle.
2. Sieve sample, retaining the 60 -120 mesh fraction.
3. Wash repeatedly in a beaker with distilled water until effluent is clear.
4. Treat with dilute (10%) nitric acid in sonic bath 3 to 5 minutes.
5. Rinse several times as above to remove released material and acid.
6. Treat with 5% HF for about 30 seconds in sonic bath (watch out - too long and it will eat your sample!).
7. Rinse well as above.
8. Place in warm oven to dry.
9. Bottle it up.

Ship to:

Electron Microprobe Laboratory
Department Geology and Geophysics
115 South 1460 East, Room 383
Salt Lake City, UT 84112-0102

Attention: Barbara Nash