Molecular water in beryl, VIAl2 [Be3Si6O18]•nH 2O, as a function of pressure and temperature:: An experimental study

DC FieldValueLanguage
dc.contributor.authorPankrath, R
dc.contributor.authorLanger, K
dc.date.accessioned2024-01-04T10:34:49Z-
dc.date.available2024-01-04T10:34:49Z-
dc.date.issued2002
dc.identifier.issn0003-004X
dc.identifier.urihttp://osnascholar.ub.uni-osnabrueck.de/handle/unios/73168-
dc.description.abstractThe incorporation of molecular water into the c-parallel structural channels in end-member beryl Al-VI(2)[Be(3)jSi(6)O(18)].nH(2)O, where n(H2O) = 1.00 corresponds to 3.24 wt% H2O, was Studied experimentally in the temperature-pressure range 400-950degreesC and 1-14.5 kbar (P-H2O = P-tot). Time-dependent studies ensured that the incorporation of water by beryl had reached the equilibrium Values in the hydration experiments. Increasing water contents were found to enhance the refractive indices of beryl as follows: n(epsilon) = 1.5585 0.0080.wt% H2O (r = 0.986) n(omega) = 1.5616 0.0086.wt% H2O (r = 0.978) These relations were used to determine the water contents attained in the equilibrium experiments, and were calibrated using synthetic beryls, the water contents of which had been determined gravimetrically with an accuracy of /-0.06 wt% H2O. The incorporation of water into the structural channels of beryl leaves the hexagonal a-axis unchanged. a = 9.2110( 10) A. c and V increase as: c (Angstrom) = 9.1893 0.0020.wt% H2O (r = 0.974) V (Angstrom(3)) = 674.98 0.203.wt% H2O (r = 0.936) Two isobars at 3.4 and 10.8 kbar with P-H2O = P-total could be modeled as: wt% H2O (P) = a - bT (degreesC) cT(2) (degreesC) 3.4 kbar: a = 4.10, b = 5.90.10(3), c = 0.31.10(5) (r = 0.963) 1 0.8 kbar: a = 3.31, b = 0.514.10(-3), c = 0.00 (r = 0.941) Similarly, the two isotherms at 600 and 900degreesC could be modeled as: wt%H2O (T) = a bP (kbar) - cP(2) (kbar) 500degreesC: a = 0.94, b = 0.261, c = 0.0075 (r = 0.949) 900degreesC: a = 0. 19, b = 0.331, c = 0.0092 (r = 0.964) These relations together with data points from additional experiments were used to construct a (P-H2O = P-tot) - T field of isohydrons for the system end-member beryl-H2O. Comparing n(H2O)-P sections at 600degreesC for beryl obtained in this study with data for Mg-cordierite obtained from the literature, proves nearly the same equilibrium contents of water in both minerals.
dc.language.isoen
dc.publisherMINERALOGICAL SOC AMER
dc.relation.ispartofAMERICAN MINERALOGIST
dc.subjectBEO-AL2O3-SIO2-H2O
dc.subjectCORDIERITE
dc.subjectGeochemistry & Geophysics
dc.subjectMineralogy
dc.subjectMINERALS
dc.subjectSYSTEM
dc.titleMolecular water in beryl, <SUP>VI</SUP>Al<sub>2</sub> [Be<sub>3</sub>Si<sub>6</sub>O<sub>18</sub>]•<i><sub>n</sub></i>H<sub> 2</sub>O, as a function of pressure and temperature:: An experimental study
dc.typejournal article
dc.identifier.isiISI:000173697700005
dc.description.volume87
dc.description.issue2-3
dc.description.startpage238
dc.description.endpage244
dc.publisher.place1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA
dcterms.isPartOf.abbreviationAm. Miner.
local.import.remainsaffiliations : Technical University of Berlin; University Osnabruck
local.import.remainsweb-of-science-index : Science Citation Index Expanded (SCI-EXPANDED)
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