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Effect of CaCl/sub 2/ and FeCl/sub 2/ on phase relations for the halite trend

Conference · · Geol. Soc. Am., Abstr. Programs; (United States)
OSTI ID:6651438

To evaluate the possibility that highly saline (halite trend) fluid inclusions in porphyry Cu and skarn deposits were not formed by halite subtraction, the authors have measured the bulk compositions of halite trend inclusions at the Granisle, B.C., porphyry copper deposit and have determined preliminary phase relations in the NaCl-KCl-CaCl/sub 2/-H/sub 2/O and NaCl-KCl-FeCl/sub 2/-H/sub 2/O systems. Bulk compositions for the Granisle inclusions were determined by SEM analyses of opened inclusions and of residues of decrepitated inclusions, supplemented by phase volume, gas chromatogrphic and leachate analyses. Synthetic fluid inclusions provided preliminary data on the halite-sylvite cotectic in the NaCl-KCl-FeCl/sub 2/-H/sub 2/O system. At t>ca. 200C hematite or magnetite formed suggesting: a) generation of H/sub 2/ and HCl in expts., and b) presence of free HCl in natural inclusions high in Fe. These data show that CaCl/sub 2/ and FeCl/sub 2/ affect phase relations in the same way, as has been demonstrated previously. Using this parallelism they estimate from halite and sylvite disappearance temperatures and multidimensional regressional analyses from the analytical data that, as projected to zero H/sub 2/O, the trend projects within the uncertainty to nearly pure NaCl and no CaCl/sub 2/ or FeCl/sub 2/. These results are entirely compatible with the previously proposed subtraction of halite mechanism.

OSTI ID:
6651438
Report Number(s):
CONF-8510489-
Journal Information:
Geol. Soc. Am., Abstr. Programs; (United States), Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Vol. 17; ISSN GAAPB
Country of Publication:
United States
Language:
English