• Marisa Acosta

Procedure for creating synthetic fluid inclusion pure H2O standards

The standard we have has been behaving oddly, so I need to calibrate to something else. There's really only 2-3 places to order quartz pure water fluid inclusion heating standards, and none of the people I contacted last week have responded. I'm really eager to move ahead with my data collection so I decided to make my own. Luckily, it turns out to be a pretty easy process. This method is a slightly modified version of that in

How to create synthetic fluid inclusion standard:

1) Cut synthetic quartz into small sample (2 mm x 3 mm x 5 mm or similar dimensions)

2) Heat sample at 350-400 C for a minimum of 3 hours

3) Fill beaker with HPLC water

  • If a greater fracture density is required, cool water in a refrigerator

HPLC Grade = High Pressure Liquid Chromatography Grade= v. pure water

4) Remove sample from kiln and quickly drop into water. Leave it sit for a bit.

5) I don’t think this part is needed b/c we used HPLC water, but other methods call for it so just to be safe re-heat fractured sample overnight

6) Load sample into a Pt or Au capsule , along with more HPLC water. Optional to add amorphous colloidal silica for faster sealing of fractures .

  • This is the stage at which you would add other stuff if you’re not making a standard.

7) weigh sample after welding and put in oven @ 100 C for at least an hour before weighing again. If the weight didn't stay the same you had a bad weld and need to start over. Bummer.

8) For a standard you want to be on the critical isochore of pure water. I chose 800°C and 1411 bar (Shide Mao, Per. Comm.) as calculated by the IAPWS-95 formulation of the equation of state of water (Shi & Mao, 2011).

  • Or P&T of interest to your study

9) Remember to get the CSPV to P & T prior to raising sample (magnet should be down until everything is primed). Otherwise you’ll get non-critical homogenization of early formed fluid inclusions.

The CSPV before use.

I just put the capsule together today and am going to let it cook while I'm at the Mining and Mineral Symposium next week in Butte, MT. Will upload pics of synthetic flincs when I return!

Ref. :

Shi, L., & Mao, S. (2012). Applications of the IAPWS-95 formulation in fluid inclusion and mineral-fluid phase equilibria. Geoscience Frontiers, 3(1), 51-58.

Sterner S. M. and Bodnar R. J. (1984) Synthetic fluid inclusions in natural quartz. I. Compositional types synthesized and applications to experimental geochemistry. Geochim. Cosmochim. Acta 48, 2659–2668.


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