Mineralogical Magazine · 1987 · 38 citations · 9 references
Natural SciencesEarth SciencesGeologyElemental AnalysisGeochemistryInorganic ChemistryMetamorphic MineralsMineral ChemistryMineral GenesisMineral GeochemistryPhysical Properties Of MineralsSilicate MineralsGranulite Facies GeochemistryOptical Classification Of MineralsOptical PropertiesOptical Properties Of MineralsPegmatite DepositsUnit Cell BasisUnit Cell ParametersUnit Cell Volume
Abstract Chlorine-rich potassium hastingsite occurs in a calcareous pegmatite, a replacement zone and an amphibolite lens within hornblende gneiss on West Ongul Island, Lützow-Holm Bay, East Antarctica. The amphibolite lens and hornblende gneiss were metamorphosed to the kyanite-sillimanite grade of the granulite facies during Proterozoic metamorphism. Chemical analysis (3.27 wt.% Cl), unit cell parameters and optical properties of the Cl-rich potassium hastingsite are given. Cl-rich (> 3 wt.%) calcic amphiboles reported from various rock types are mostly more than 0.9 in (Na+ K) content, more than 0.4 in K/(Na + K) ratio, more than 0.75 in Fe 2+ /(Fe 2+ + Mg + Mn) ratio and more than 1.9 in Al IV content (total iron as FeO and O = 23). The unit cell volume of Cl-rich hastingsite is distinctly larger than that of Cl-poor hastingsite.
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