Abstract
The possibility of using hydrothermal fluorite as an Sm–Nd geochronometer is based on the results of an REE pattern study of this mineral (Chernyshev et al., 1986). As a result of REE fractionation, in many cases, the Sm/Nd ratio achieves a multifold increase compared with its level in terrestrial rocks, and the radiogenic shift of the 143Nd/144Nd isotope ratio reaches 10–20 εNd units over a short time interval (as soon as tens of Ma). This is a necessary prerequisite for Sm–Nd isochron dating of fluorite. Zonal polychrome fluorite from a vein referred to the final stage of large-scale uranium mineralization at the Sterl’tsovka deposit in the ore field of the same name located in the eastern Transbaikal region has been dated using the 143Nd/144Nd method. To optimize isochron construction, local probes with high and contrasting Sm/Nd ratios have been sampled from the polished surfaces of two samples, taking into account the REE pattern of zonal fluorite. Sm–Nd isochron dating has been carried out separately for each sample. The 147Sm/144Nd и 143Nd/144Nd ratios vary within the intervals 0.5359–2.037 and 0.512799–0.514105, respectively. Two isochrons, each based on six fluorite probes, have been obtained with the following parameters, which coincide within 2σ uncertainty limits: (1) t = 134.8 ± 1.3 Ma, (143Nd/144Nd)0 = 0.512310 ± 13, MWSD = 0.43 and (2) t = 135.8 ± 1.6 Ma, (143Nd/144Nd)0 = 0.512318 ± 10, MWSD = 1.5. The mean age of fluorite based on two isochron datings is 135.3 ± 1 Ma. Comparison of this value with the most precise dating of pitchblende related to the ore stage in the Strel’tsovka ore field (135.5 ± 1 Ma) shows that four mineralization stages, distinguished by geological and mineralogical data, that were completed with the formation of polychrome fluorite veins 135.3 ± 1 Ma ago, represent a single and indivisible hydrothermal process whose duration does not exceed 1 Ma.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Aleshin, A.P., Velichkin, V.I., and Krylova, T.L., Genesis and formation conditions of deposits in the unique Strel’tsovka molybdenum–uranium ore field: new mineralogical, geochemical, and physicochemical evidence, Geol. Ore Deposits, 2007, vol. 49, no.5, pp. 392–412.
Andreeva, O.V., Golovin, V.A., Kozlova, P.S., Sel’tsov, B.M., Chernyshev, I.V., Arakelyants, M.M., Gol’tsman, Yu.V., and Bairova, E.D., Evolution of Mesozoic magmatism and ore-forming metasomatic processes in the southeastern Transbaikal Region (Russia), Geol. Ore Deposits, 1996, vol. 38, no. 2, pp.101–113.
Brookins, D.G., Aqueous geochemistry of rare earth elements, in Reviews in Mineralogy. Volume 21. Geochemistry and Mineralogy of Rare Earth Elements, Lipin B.R. and McKay, G.A., Eds., Chelsea: 1989, 201–225.
Burt, D.M. Compositional and phase relations among rare earth element minerals,” in Reviews in Mineralogy. V. 21. Geochemistry and Mineralogy of Rare Earth Elements, Lipin B.R. and McKay, G.A., Eds., Chelsea: 1989, pp. 259–307.
Chernyshev, I.V. and Golubev, V.N. The Strel’tsovskoe Deposit, eastern Transbaikalia: isotope dating of mineralization in Russia’s largest uranium deposit, Geochem. Int. 1996, vol. 34, no. 10, pp. 834–846.
Chernyshev, I.V., Troitsky, V.A., and Zhuravlev, D.Z., Pb,Sr and Nd isotopes in minerals of tungsten deposits, Abstracts of Sixth International Conference Geochronology, Cosmochronology and Isotope Geology. Abstract. Terra Cognita, 1986, vol. 6, no. 2, p. 226.
Chernyshev, I.V. and Zhuravlev, D.Z., Application of fluorite for Sm-Nd dating, in Soviet–Japanese Symposium on Isotope Geology. Abstract, Moscow, 1987, pp. 80–82.
Chugaev, A.V., Safonov, Y.G., and Chernyshev, I.V., Age of Kolar Au-deposits (India): Rb-Sr and Sm-Nd age constraints, International Symposium on “Applied Geochemistry in the Coming Decades”, Hyderabad (India), 2001, p. 76.
Dubinina E.O., Chugaev, A.V., Ikonnikova, T.A., Avdeenko A.S., and Yakushev, A.I. Sources and fluid regime of quartz–carbonate veins at the Sukhoi Log Gold Deposit, Baikal–Patom Highland, Petrology, 2014, vol. 22, no. 4, 329–358.
Ishchukova, L.P., Igoshin, Yu.A., Avdeev, B.V., Gubkin, G.N., Filipchenko, Yu.A., Popova, A.I., Rogova, V.P., Makushin, M.F., Khomentovskii, B.N., and Spirin, E.K., Geologiya Urulyunguevskogo rudnogo raiona i molibdenuranovykh mestorozhdenii Strel’tsovskogo rudnogo polya (Ore District and Molybdenum–Uranium Deposits of the Strel’tsovka Ore Field), Moscow: ZAO “Geoinformmark”, 1998.
Ivanova, G.F., Naumov V.B., Kolesov, G.V., and Chernyshev, I.V., Ore-forming fluid sources of tungsten deposits: rare earth element, radiogenic isotopes and fluid inclusion evidence, in Source, Transport and Deposition of Metals., Rotterdm: A.A. Balkema–Brookfield, 1991, pp. 301–303.
Kempe, U., Belyatsky, B.V., Krymsky, R.S., Kremenetsky, A.A., and Ivanov, P.A., Sm-Nd and Sr isotope systematics of scheelite from the giant Au(-W) deposit Muruntau (Uzbekistan): implications for the age and sources of Au mineralization, Mineral. Deposit, 2001, vol. 36, pp. 379–392.
Komarova G.N. Mineral composition and specifics of the formation of the Garsonuiskoe skoe fluorite deposit in Eastern Transbaikalia, Extended Abstract of Cand. Sci. (Geol.-Min.) Dissertation, Moscow: 1972.
Kotov, P.A. and Kotova, A.I. Garsonui deposit, in Mestorozhdeniya Zabaikal’ya (Transbaikalian Deposits), Moscow: Geoinformmark, 1995, vol. 1, pt. 2. pp. 179–184.
Laverov, N.P., Velichkin, V.I., Vlasov, B.P., Aleshin, A.P., and Petrov, V.A., Uranovye i molibden-uranovye mestorozhdeniya v oblastyakh razvitiya kontinental’nogo vnutrikorovogo magmatizma: geologiya, geodinamicheskie i fiziko-khimicheskie usloviya formirovaniya (Uranium and Molybdenum–Uranium Deposits in the Distribution Areas of the Continental Intracrustal Magmatism, Geology, Geodynamic and Physicochemical Conditions of Formation), Moscow: IFZ RAN–IGEM RAN, 2012.
Ludwig, K.R., ISOPLOT/Ex.Version 2.06. A geochronological toolkit for Microsoft Excel, Berkley Geochronology Center Sp. Publ, 1999, no. 1a.
Mel’nikov I.V. Mineralogical–geochemical features of the formation of uranium deposit, in Materialy po geologii uranovykh mestorozhdenii (Proceedings on Geology of Uranium Deposits), Moscow: VIMS, 1985, vol. 93, no. 2, pp. 74–82.
De Paolo, D., Neodymium Isotope Geochemistry. an Introduction, Springer-Verlag, 1998.
Uysal, I.T., Zhao, J.X., Golding, S.D., et al., Sm-Nd dating and rare-earth element tracing of calcite: implication for fluid flow events in the Bowen Basin, Australia, Chem. Geol., 2007, vol. 238, pp. 63–71.
Vinokurov, S.F., Golubev, V.N., Krylova, T.L., and Prokof’ev, V.Yu., “REE and fluid inclusions in zoned fluorites from eastern Transbaikalia: distribution and geochemical significance, Geochem. Int., 2014, vol. 52, no. 8, pp. 654–669.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © I.V. Chernyshev, V.N. Golubev, A.P. Aleshin, Yu.O. Larionova, Yu.V. Gol’tsman, 2016, published in Geologiya Rudnykh Mestorozhdenii, 2016, Vol. 58, No. 6, pp. 503–512.
Rights and permissions
About this article
Cite this article
Chernyshev, I.V., Golubev, V.N., Aleshin, A.P. et al. Fluorite as an Sm–Nd geochronometer of hydrothermal processes: Dating of mineralization hosted in the Strel’tsovka uranium ore field, eastern Baikal region. Geol. Ore Deposits 58, 447–455 (2016). https://doi.org/10.1134/S1075701516060027
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1075701516060027