Abstract
A study of the abundance of Be in the gem sediments of Sri Lanka shows that Be is found in the range of 1–13 ppm. Be shows an irregular distribution among sediments. It occurs in the silicate form and due to the proximity to the beryllium bearing rocks, namely granites and pegmatites of the Highland and Southwest Groups of Sri Lanka, very little decomposition of the Be-bearing minerals had taken place. This is further aided by the high resistance to weathering of the beryllium minerals, particularly beryl and chrysoberyl.
The beryllian granites and pegmatites of the Precambrian of Sri Lanka are presumed to have been formed due to the magmatic activity associated and related to charnockitic rocks abundant in the main gem bearing areas of Sri Lanka.
Fluorine is found in the range of 400–2,000 ppm and the F/Be ratios for all the areas studied show a range of 54–441. The analysis of the averages of these ratios do not show any particular anomaly in any of the areas studied. The narrow ranges of the F/Be ratios indicate the similar conditions under which weathering and geochemical transportation had taken place in the gem fields of Sri Lanka.
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Bailey, J.C.: Fluorine in granitic rocks and melts: A review; Chem. Geol. 19, 1–42 (1977)
Beus, A.A.: Geochemistry of beryllium: Geochemistry (USSR) English Trans. 1, 511–531 (1956)
Beus, A.A.: Distribution of beryllium in granites: (USSR) English Trans. 5, 432–437 (1961)
Beus, A.A.: Geochemistry of beryllium and genetic types of beryllium deposits: W.H. Freeman & Co., pp. 389 (1966)
Brinck, J.W., Hoffmann, A.: The distribution of beryllium in the Oslo region — Norway — a geochemical, stream sediment study: Econ. Geol. 59, 79–96 (1964)
Cooray, P.G.: Geology of Sri Lanka. In: Nutalaya, P. (ed), Regional Conf. Geology & Mineral Resources of Southeast Asia, 3rd: Bangkok, p. 701–710 (1978)
Dahanayake, K.G.A., Liyanage, A.N., Ranasinghe, A.P.: Genesis of sedimentary gem deposits in Sri Lanka: Sedimentary Geology 25, 105–115 (1980)
Dissanayake, C.B., Nawaratne, S.W.: The occurrence of gold in the gem beds of Sri Lanka: Econ. Geol. 76, 733–738 (1981)
Dawey, J.F., Burke, K.E.A.: Tibetan, Variscan and Precambrian basement reactivation: Products of continental collosion: J. Geol. 81, 603–692 (1973)
Everest, D.A.: The chemistry of beryllium: Elsevier 146 pp. (1964)
Goldschmidt, V.M.: Principles of distribution of chemical elements in minerals and rocks: J. Chem. Soc. London 5, 655–673 (1937)
Gordon, M., Murata, K.J.: Minor elements in Arkansas bauxite. Econ. Geol. 47, 169–179 (1952)
Grew, E.S.: Surnamite, taaffeite, and berryllian sapphirine from pegmatites in granulite-facies rocks of Casey Bay, Enderby Land, Antarctica: American Mineralogist, 66, 1022–1033 (1981)
Gübelin, E., Moor, M.R., Oberholzer, W.F.: Taprobanit — ein neuer Edelstein aus Sri Lanka: Z. Dt. Gemmol. Ges. 30, 197–205 (1981)
Hapuarachchi, D.J.A.C.: The granulite facies of Sri Lanka: Sri Lanka Geol. Survey Dept. Prof. Paper 4, 29 (1975)
Hirst, D.M.: The geochemistry of modern sediments from the Gulf of Raria — II. The location and distribution of trace elements: Geochim. Cosmochim. Acta 26, 1147–1187 (1962)
Hörmann, P.K.: Beryllium. In: Hand Book of Geochemistry, V.II/I. Wedepohl K.H. (ed.) Springer, Berlin Heidelberg New York
Jaywardena, D.E. de. S., Carswell, D.A.: The geochemistry of charnockites and their consituent ferromagnesian minerals from the Precambrien of southeast Sri Lanka: Mineralogical Mag 40, 541–554 (1976)
Jefferey, P.G.: Chemical Methods of Rock Analysis, Pergamon Press, 523 p. (1975)
Kanisawa, S.: Contents and behaviour of fluorine in granitic rock, Kitakami mountains, Northeast Japan: Chem. Geol. 24, 57–67 (1979)
Katz, M.B.: On the origin of the Ratnapura gem deposits of Ceylon: Econ. Geol. 67, 113–115 (1972)
Lacroix, A.: Les rouches dépourves de feldspath du cortége des sakénites (Madagascar); composition chimique de cet ensemble. Compt. Rend. 210, 193–196 (1940)
Martignole, J.: Charnockite genesis and the proterozoich crust: Precam. Res. 9, 303–310 (1979)
Merrill, J.R., Lyden, E.F.X., Honda, M., Arnold, J.R.: Sedimentary geochemistry of the beryllium isotopes. Geochim. Cosmochim. Acta 18, 108–129 (1960)
Mitchel, K.: “Tabrobanite” is taaffeite: J. Gemm. 18, 113 (1982)
Munasinghe, T., Dissanayake, C.B.: Are charnockites metamorphosed Archean volcanic rocks? — A case study from Sri Lanka: Precamb. Res. 12, 459–470 (1980)
Munasinghe, T., Dissanayake, C.B.: The origin of gemstones of Sri Lanka: Econ. Geol. 76, 1216–1225 (1981)
Munasinghe, T., Dissanayake, C.B.: A plate tectonic model for the geological evolution of Sri Lanka. J. Geol. Soc. Ind. 23, 369–380 (1982)
Overstreet, W.S.: The geologic occurrence of monazite, U.S. Geol. Survey Prof. paper 530, 294 (1967)
Rankama, K., Sahama, Th.G.: Geochimistry: Univ. Chicago Press (1950)
Shawe, D.R., Bernold, S.: Distribution of beryllium in igneous rocks. U.S. Geol. Survey Prof. paper 501-B (1964)
Silva, K.K.M.W.: Some geological aspects of the Elahera gem field Sri Lanka., (abs) Sri Lanka Assoc. adv. sci. 32nd sess. (1976)
Wadia, D.N., Fernando, L.J.D.: Gems and semi-precious stones of Ceylon: Ceylon Dept. Mineral Resources, Prof. paper 2, 13–44 (1945)
Warner, L.A., Holser, W.T., Wilmarth, V.R., Cameron, E.N.: U.S.G.S. Prof. paper 318, 197 (1959)
Wilson, A.F.: The charnockitic granites and associated rocks of central Australia: Trans. Roy. Soc. S. Aust. 83, 37–76 (1960)
Wilson, A.F.: A new occurrence of sapphirine and the significance of sapphirine in the granulite terrains of Western Australia: Am. Mineralogist 47, 207–208 (1962)
Wilson, A.F., Hudson, D.R.: The discovery of beryllium-bearing sapphirine in the granulites of the Musgrave Ranges (Central Australia): Chem. Geol. 2, 209–215 (1967)
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Rupasinghe, M.S., Banerjee, A., Pense, J. et al. The geochemistry of beryllium and fluorine in the gem fields of Sri Lanka. Mineral. Deposita 19, 86–93 (1984). https://doi.org/10.1007/BF00206601
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DOI: https://doi.org/10.1007/BF00206601