Barbosalite, frondelite and other phosphates from Gunheath China Clay Pit, St Austell, Cornwall, England

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Authors:Elton, Nicholas J.
Author Affiliations:Primary:
Tregears, Little Treviscoe, Saint Austell, United Kingdom
Volume Title:Journal of the Russell Society
Source:location varies [Journal of the Russell Society, Vol.7(Part 1), p.15-18. Publisher: Russell Society,], United Kingdom. ISSN: 0263-7839
Publication Date:1998
Note:In English. 15 refs.; illus., incl. 4 tables
Summary:Several unusual iron and iron-containing phosphates occur in N or NE trending iron oxide veins in kaolinised granite at Gunheath China Clay Pit, St Austell, Cornwall. Re-examination of specimens collected around 1987 has shown the mixed valence iron phosphates barbosalite, (Ca0.01Mn0.07Fe2.91)Σ = 2.99(PO4)1.96(OH)2.16 and frondelite (Mn0.57Ca0.12Fe4.27)Σ = 4.96(PO4)3.08(OH)4.68occurring in intimate association. Unit cell dimensions for the frondelite (a = 13.960(3), b = 16.874(3), c = 5.169(1) Å) are significantly different from previously published values. Hydroxylchlorapatite, fluorapatite and cassiterite are also present in these specimens. In a second group of specimens, barbosalite occurs in intimate association with dufrenite, hentschelite, chalcosiderite-turquoise, fluorapatite, quartz and grains of altered stannoidite. Vesicles in the matrix contain leucophosphite and, more rarely, libethenite, torbernite and brochantite. These specimens represent the first occurrence of frondelite and chlorapatite in the British Isles, and the second of barbosalite and hentschelite.
Sections:Mineral data
Subsections:Non-silicates
Subjects:Barbosalite; Chemical composition; Chlorapatite; Granites; Igneous rocks; Metals; Occurrence; Phosphates; Plutonic rocks; Cornwall England; England; Europe; Great Britain; United Kingdom; Western Europe; Frondelite; Gunheath China Clay Pit; Hentschelite; Iron phosphates; Saint Austell England
Coordinates:N504000 N504000 W0044500 W0044500
Abstract Numbers:99M/774
Record ID:1999026133
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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