Low pressure experiments in piston cylinder apparatus: calibration of newly designed 25 mm furnace assemblies to P = 150 MPa

We present new pressure calibration experiments demons trating that the piston cylinder apparatus is suit-able for experiments at pressure as low as 150 MPa. Two newly designed 25 mm furnace assembly have
been developed and calibrated using two differe nt calibration methods: the NaC l melting curve and the sol-ubility of H2 O in albitic and rhyolitic melts. The NaCl calibration experiments performed in the pressure range
150 –500 MPa yield the pressure correction that has to be applied to the nominal pressure in order to have the
equivalent (real) pressure on the sample. This correction varies as a function of the experime ntal pressure as
follows:
Pcorrection MPaðÞ¼ −0 :115xP nominal MPaðÞþ 78 : 23
The H 2O solubility experiments in albitic and rhyolitic melts con firm the corrections determined using the
NaCl calibration method. Moreover, because these experiments are performed at temperatures higher than
those used for NaCl calibration, they demonstrate that the pressure correction is not affected by temperature
in the range 800– 1000 °C. The accuracy of the pressure estimate associated wi th the calibration methods is ±
25 MPa.
The major advantage of using the new assemblies is that low pressure experiments, which require rapid
heating and quenching rates (e.g. volcanic and hydrothermal systems), can be performed with the same
ease and precision as standard high pressure experiments for which piston cylinder is routinel y used.

Sapienza — Università di
Roma, Istituto Nazionale di Geofisica e Vulcanologia, Depths of the
Earth Company, NSF EAR-0838563 to G. Moore, and Science Founda-tion Sweden to V.R. Troll.
References

Baker, D.R., 2004. Piston-cylinder calibration at 400–500 MPa: a comparison of using
water solubility in albite melt and NaCl melting. American Mineralogist 89,
1553 –1556.
Behrens, H., Romano, C., Nowak, M., Holtz, F., Dingwell, D.B., 1996. Near-infrared spec-troscopic determina tion of water species in glasses of the system MAlSi 3O 8
(M = Li, Na, K): an interlaboratory study. Chemical Geology 128, 41 –63.
Behrens, H., Meyer, M., Holtz, F., Benne, D., Nowak, M., 2001. The effect of alkali ionic
radius, temperatu re, and pressure on the solubility of water in MAlSiO melts
(M = Li, Na, K, Rb). Chemical Geology 174, 275 –289.Bohlen, S.R., 1984. Equilibri a for precise pressure calibration and a frictionless furnace
assembly for the piston-cylinder app aratus. Neues Jahrbuch für Mineralogie,
Monatshefte 9, 404 –412.
Boyd, J.R., England, J.L., 1960. Apparatus for phase-equili brium measureme nts at pres-
sures up to 50 kilobars and temperatures up to 1750 °C. Journal of Geophy sical Re-
search 65, 741– 748.
Devine, J.D., Gardner, J.E., Brack, H.P., Layne, G.D., Rutherford, M.J., 1995. Comparison of
microanalytical methods for estimating H2 O contents of silicic volcanic glasses.
American Mineralogist 80, 319 –328.
Freda, C., Baker, D.R., Ottolini, L., 2001. reduction of water loss from gold –palladium
capsules during piston-cylinder experiments by use of pyrophyllite powder. Amer-
ican Mineralogist 86, 234– 237.
Freda, C., Gaeta, M., Misiti, V., Mollo, S., Dol fi, D., Scarlato, P., 2008. Magma –carbonate
interaction: an experimental study on ultrapotassic rocks from Alban Hills (Central
Italy). Lithos 101, 397– 415.
Holloway, J.R., Wood, B.J., 1988. Simulating the Earth. Unwin Hyman, Winchester, Mas-
sachusetts. 196 pp.
Holtz, F., Becker, A., Freise, M., Johannes, W., 2001. The water-undersaturated and dry
Qz-Ab-Or system revisited. Experimental results at very low water activities and
geological implic ations. Contributions to Mineralogy and Petrology 141, 347 –357.Johannes, W., Bell, P.M., Mao , H.K., Boettche r, A.l., Chipman, D.W., Hays, J.F., Newton,
R.C., Seifert, F., 1971. An interlaboratory comparison of piston -cylinder pressure
calibration using the albite-breakdown reaction. Contributions to Mineralogy and
Petrology 32, 24 –38.
Masotta, M., Freda, C., Gaeta, M., 2012. Origin of crystal-poor, differentiated magmas:
insights from thermal gradient experiments. Contributions to Mineralogy and Pe-trology 163, 49 – 65.
Moore, G., Vennemann, T., Carmichael, I.S.E., 1998. An empirical model for the solubil-ity of H2O in magmas to 3 kbar. American Mineralogist 83, 36– 42.
Moore, G., Roggensack, K., Klonowski, S., 2008. A low-pressure-high-temperatur e tech-nique for the piston-cylinder. American Mineralogist 93, 48 –52.
Nelson, S.T., Montana, A., 1992. Sieve-textured plagioclase in volcanic rocks produced
by rapid decompressio n. American Mineralogist 77, 1242 – 1249.
Siewert, R., Büttner, H., Rosenhauer, M., 1998. Experimental investigation of thermody-namic melting properties in the system NaCl – KCl at pressures of up to 7000 bar.
Neues Jahrbuch für Mineralogie, Abhandlu ngen 172, 259– 278.