3. Cleaning Pre-prepared samples

Samples that are recieved from from outside the OSU Argon Lab may aready be prepared. The proceedures outlined here are for cleaning them.

!!BE CLEAN AND PREVENT CROSS CONTAMINATION!! Only work on one mica sample at a time Important! You must always be aware of any mica separate (muscovite and biotite, and sericite) especially the fine-grained micas. It is extremely easy to cross contaminate from one mica sample to another, so always check your hands and work area for mica from a previous sample before proceeding onto the next sample.

A. Put the mineral separate into an appropriate size beaker. B. Soak in Acetone for ½ hour. Stir occasionally C. Rinse with ethanol/Ethyl alcohol and then let sample soak in ethanol for ½ hour. Stir occasionally D. Rinse with Milli-Q water 3 times. E. Soak in Milli-Q water for ½ hour. F. Put in drying over overnight. G. Once the micas are dried you will then sieve them out to the following sizes. Be sure to only use the non-resin sieves, as the mica and feldspars like to stick to resin and it is difficult to get clean:

  1. Coarse-grained (600-345 μm)

  2. Fine-grained (212-150 μm)

Note! There may be some samples that are finer than 150 μm. Note! There may be some samples that are >1mm, these samples will have to be crushed down using the small mortar and pestle, then cleaned using the procedure described above. Please talk to Dan if this situation arises.

H. After the sample has been sieved you will then paper shake the micas to obtain the cleanest, and hopefully, inclusion free mica flakes. I. Final step is to pick 1-10 mg’s of ultra-clean inclusion free material (the weights will depend on age and material type). Note! Some of the hornblende and pyroxene samples might require up to 50 mg or at least 100 crystals for Total Fusion analysis…Please talk to Dan if these types of separates are needed..

Note! Separation of hornblende can also be achieved by utilizing the paper shaking method….however, the hornblende can be cleaned in the ultrasonic bath up to 1 hour.

A Final Note! Some hornblende, pyroxene and other feldspars might need acid leaching, or heavy liquids. Please talk to Dan for appropriate directions as some samples might may or may not need these procedures.

!!BE CLEAN AND PREVENT CROSS CONTAMINATION!!