Calcium and Magnesium‐bearing Sabugalite from the Tono Uranium Deposit,Central Japan |
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| Authors: | Masataka Nakata Eiji Sasao Kosei Komuro |
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| Affiliation: | 1. Faculty of Education, Tokyo Gakugei University, , Koganei, Japan;2. Geological Isolation Research and Development Directorate, Japan Atomic Energy Agency, , Mizunami‐shi, Japan;3. Faculty of Life and Environmental Sciences, University of Tsukuba, , Tsukuba, Japan |
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| Abstract: | ![]()
Calcium and magnesium‐bearing sabugalite occurs as aggregations of yellowish platy crystals in veinlets or druses in conglomerate from the oxidized parts of the Tono uranium deposit, Central Japan. X‐ray powder diffractometry of this mineral has reflections consistent with previous powder diffraction data of sabugalite. It is included in the monoclinic system with space group C2/m and calculated cell parameters of a = 19.68Å, b = 9.89Å, c = 9.82Å α = γ = 90°, β‐96.93° and V = 1897.83Å3. Chemical analysis yields a formula of (Ca0.10 Mg0.09)Σ0.19Al0.53(UO2)2.04((PO4)1.99(AsO4)0.01)Σ2.00·11.22H2O. EMPA mapping shows that the mineral is compositionally uniform with no micron‐scale layering. Charge of cations including Ca and Mg in the cation‐H2O layer is 1.98 being identical to that of autunite group minerals. This suggests that the charge balance in the cation‐H2O layer of the mineral could be made by the alkaline earth or alkaline elements rather than by hydrogen ions. |
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| Keywords: | cation‐H2O layer chemical composition sabugalite Tono Uranium Deposit |
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