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Baotite occurs as a late phase in the Kval?ya lamproite dyke and in the fenitized granite adjacent to the dyke, suggesting that baotite formed during reactions between rock and fluids derived from a volatile-rich lamproitic magma. Most of the analyzed grains of baotite from the Kval?ya lamproite show compositions close to the ideal Nb-free end-member Ba4Ti8Si4O28Cl. Compilation of all published baotite analyses suggests that the major compositional variations of baotite occur between the Nb-free end member Ba4Ti8Si4O28Cl, and a Nb-rich end member Ba4Ti2Fe2+ 2Nb4Si4O28Cl. However, a Pb-bearing baotite, showing significant concentrations of Ca, Sr, Pb and K, and approximately 3 Ba p.f.u., was also identified from the Kval?ya lamproite. Euhedral fluorapatite formed as an early phase during crystallization of the lamproite magma, while anhedral REE-rich fluorapatite overgrowths on the euhedral grains formed during reactions with the late magmatic fluid. Fluorapatite contains up to 1.2?F p.f.u., but only traces of Cl. Other F-rich, but Cl-poor minerals of the lamproite include fluoro-potassic-magnesio-arfvedsonite, fluoro-phlogopite, and yangzhumingite. The presence of baotite together with a range of high-F, but low-Cl mineral phases suggests that the minerals formed in equilibrium with a high-F, Cl-bearing hydrous fluid. The high Cl-content of baotite demonstrates that Cl is strongly partitioned into this mineral in the presence of a Cl-bearing F-rich hydrous fluid. We suggest that a combination of high aSi, aTi, aBa, and fO2, but low aCa of the fluid enabled baotite formation. 相似文献
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V. V. Sapozhnikov N. M. Zozulya S. I. Stolyarskii A. V. Azarenko D. N. Katunin 《Oceanology》2010,50(4):627-629
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L. M. Lyalina Ye. E. Savchenko E. A. Selivanova D. R. Zozulya 《Geology of Ore Deposits》2010,52(7):641-645
The detailed study of the mineral composition of the nepheline syenite pegmatite from the Saharjok Intrusion has resulted
in the finding of behoite and mimetite, a mineral species identified in the Kola region for the first time. The pegmatite
body at the contact between nepheline syenite and essexite is unusual in textural and structural features and combination
of mineral assemblages including unique beryllium mineralization. Behoite Be(OH)2 is an extremely rare beryllium mineral. It occurs as powderlike aggregates in the leaching cavities between euhedral pyroxene
crystals. Behoite was identified by comparison of X-ray powder diffraction data of the studied mineral phase and behoite from
the Be-bearing tuff in the type locality of this mineral (Utah, United States). Mimetite was found in the same pegmatite of
the Saharjok intrusion. It forms unusual parallel-fibrous aggregates with individual fibers as long as ∼1 mm and only ∼1 μm
across. X-ray powder diffraction data and the chemical composition characterize the mineral as hexagonal phase Pb5[AsO4]3Cl. Both behoite and mimetite are the products of late hydrothermal alteration of primary minerals (meliphanite, galena, arsenopyrite,
and loellingite). The secondary phases freely crystallized in the cavities remaining after the leached nepheline. 相似文献
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D. R. Zozulya E. E. Savchenko K. Kullerud E. K. Ravna L. M. Lyalina 《Geology of Ore Deposits》2010,52(8):843-851
Unusual ultrapotassic dikes were recently found on the Kvalöya Island in Northern Norway. The dikes crosscutting granites 1.8 Ga in age are 0.1–1.0 m thick and consist of phlogopite phenocrysts in a fine-grained groundmass of K-magnesioarfvedsonite, orthoclase, apatite, and secondary chlorite. According to the composition of the rock-forming minerals (4.5–6.0 wt % K2O and 0.7–3.5 wt % TiO2 in magnesioarfved-sonite, 1.6–3.6 wt % FeO in orthoclase, 9.2–10.7 wt % Al2O3 and 2.1–2.6 wt % TiO2 in phlogopite) and its bulk chemical composition (K/Na = 2.3–2.9, K/Al = 1.0–1.2, (Na + K)/Al = 1.4–1.7, Mg# V = 65–73, (La/Yb) n = 100–140, 3.2–4.0 wt % TiO2, 0.55–1.47 wt % BaO, 2.5–3.0 wt % P2O5, 2650–3000 ppm Zr, 900–1260 ppm REE total, 2300–2500 ppm Sr), the rock corresponds to lamproite of the transitional type. The unique chemical composition of the rock resulted in uncommon Ti-Ba-P accessory mineralization, including baotite Ba4(Ti,Nb)8Si4O28Cl (up to 5 vol %), Sr-apatite (5–7 vol %), and previously unknown Na-Mg-Ba phosphate. Baotite forms anhedral elongated and isometric grains 10–500 μm in size. It is characterized by low Nb (0.03–0.05 f.c.); admixtures of K (0.04–0.12 f.c.) and Sr (0.04–0.07) replacing Ba and Fe (0.01–0.03 f.c.); and Al (0.03–0.04 f.c.) substituting Ti. Euhedral elongated zonal apatite crystals are extremely enriched in SrO (8–12 wt %) and REE2O3 + Y2O3 (6–9 wt %) in the marginal zone. Na-Mg-Ba phosphate occurs as prismatic grains 10–100 μm in size. The atomic ratio of its major cations Na: Mg: Ba: P ～ 2: 1: 1: 2 corresponds to the conventional formula Na2MgBa(PO4)2; the mineral contains Sr, Mn, Fe, Ca, Si, and Al admixtures. 相似文献
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V. L. Zozulya 《Water Resources》2006,33(3):329-334
Migration of biogenic substances in peats of high and low-level bogs is discussed. Experiments were carried out to determine the quantitative characteristics of the absorbing capacity of peat. A high ability of peat to absorb and hold biogenic substances was revealed. This ability depends on the degree of biogenic substance decomposition and on the amount of finely divided particles, and it is not similar in different types of biogenic substances. 相似文献
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