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Uranium-lead geochronology of the Archean Imataca Series, Venezuelan Guayana Shield

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Abstract

Uranium and lead isotopic analyses of total-rock and feldspar samples from the Imataca Series indicate an early Archean (3.5+ b.y.) age for the basement gneisses. Lead isotopic evolution in most gneiss samples may approximately be described by a three-stage model. The start of the third stage is marked by a pervasive metamorphic event, locally up to pyroxene-granulite grade, at 2 b.y. ago, which commonly resulted in extensive depletion of uranium relative to lead.

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References

  • Black, L.P., Gale, N.H., Moorbath, S., Pankhurst, R.J., McGregor, V.R.: Isotopic dating of very early Precambrian amphibolite facies gneisses from the Godthaab district, West Greenland. Earth Planet. Sci. Lett. 12, 245–259 (1971)

    Google Scholar 

  • Brooks, C., Hart, S.R., Wendt, I.: Realistic use of two-error regression treatments as applied to rubidium-strontium data. Rev. Geophys. Space Phys. 10, 551–557 (1972)

    Google Scholar 

  • Cameron, A.E., Smith, D.H., Walker, R.L.: Mass spectrometry of nanogram-size samples of lead. Anal. Chem. 41, 525–526 (1969)

    Google Scholar 

  • Catanzaro, E.J., Gast, P.W.: Isotopic composition of lead in pegmatite feldspars. Geochim. Cosmochim. Acta 19, 113–126 (1960)

    Google Scholar 

  • Chase, R.L.: El Complejo de Imataca, la Anfibolita de Panamo, y la Tronjemita de Guri, rocas precámbricas del Cuadrilatero de Adjuntas-Panamo, Estado Bólivar, Venezuela. Bol. Geol. Caracas 7, 13 (1965)

    Google Scholar 

  • Doe, B.R., Hart, S.R.: The effect of contact metamorphism on lead in potassium feldspars near the Eldora stock, Colorado. J. Geophys. Res. 68, 3521–3530 (1963)

    Google Scholar 

  • Doe, B.R., Tilton, G.R., Hopson, C.A.: Lead isotopes in feldspars from selected granitic rocks associated with regional metamorphism. J. Geophys. Res. 70, 1947–1968 (1965)

    Google Scholar 

  • Doe, B.R., Zartman, R.E.: Plumbotectonics I, The Phanerozoic. In: Geochemistry of Hydrothermal Ore Deposits, 2nd ed. (H. Barnes, ed.) (in press, 1979)

  • Dorr, J. van N., III: Iron-formation in South America. Econ. Geol. 68, 1005–1022 (1973)

    Google Scholar 

  • Dougan, T.W.: Cordierite gneisses and associated lithologies of the Guri area, northwest Guayana Shield, Venezuela. Contrib. Mineral. Petrol. 46, 169–188 (1974)

    Google Scholar 

  • Dougan, T.W.: A protolith model for the Archean Imataca Complex in an area near Cerro Bolivar, Venezuelan Guayana Shield. Precamb. Res. 3, 317–342 (1976)

    Google Scholar 

  • Fahrig, W.F., Eade, K.E., Adams, J.A.S.: Abundance of radioactive elements in crystalline shield rocks. Nature 214, 1002–1003 (1967)

    Google Scholar 

  • Gaudette, H.E., Hurley, P.M., Fairbairn, H.W.: Uranium-lead zircon ages from the northern Guayana Shield. Proc. 2nd Latin-Amer. Geol. Conf. pp. 54–55 (1973)

  • Gray, C.M., Oversby, V.M.: The behavior of lead isotopes during granulite facies metamorphism. Geochim. Cosmochim. Acta 36, 939–952 (1972)

    Google Scholar 

  • Hurley, P.M., Fairbairn, H.W., Gaudette, H.E.: Progress report on early Archean rocks in Liberia, Sierra Leone, and Guayana, and their general stratigraphic setting. In: The Early History of the Earth (B.F. Windley, ed.), pp. 511–521. Chichester: Wiley 1976

    Google Scholar 

  • Hurley, P.M., Fairbairn, H.W., Gaudette, H.E., Mendoza, V., Martin, C.B., Espejo, A.: Progress report on age dating in the northern Guayana Shield. Proc. 2nd Latin-Amer. Geol. Conf. 1 (1973)

  • Hurley, P.M., Kalliokoski, J., Fairbairn, H.W., Pinson, W.H.: Progress report on the age of granulite facies rocks in the Imataca Complex, Venezuela. Proc. Ninth Inter-Guayanas Geol. Conf. pp. 431–433 (1972)

  • Jaffey, A.H., Flynn, K.F., Glendenin, L.E., Bentley, W.C., Essling, A.M.: Precision measurement of half-lives and specific activities of 235U and 238U. Phys. Rev. 4, 1889–1906 (1971)

    Google Scholar 

  • Kalliokoski, J.: Geology of north-central Guayana Shield, Venezuela. Bull. Geol. Soc. Amer. 76, 1027–1049 (1965a)

    Google Scholar 

  • Kalliokoski, J.: The metamorphosed iron ore of El Pao, Venezuela. Econ. Geol. 60, 100–116 (1965b)

    Google Scholar 

  • Kanasewich, E.R.: The interpretation of lead isotopes and their geological significance. In: Radiometric Dating for Geologists (E.I. Hamilton and R.M. Farquhar, eds.), pp. 147–223, New York: Interscience Publishers 1968

    Google Scholar 

  • Krogh, T.E.: A low-contamination method for hydrothermal decomposition of zircon and extraction of U and Pb for isotopic age determinations. Geochim. Cosmochim. Acta 37, 485–494 (1973)

    Google Scholar 

  • Menéndez, A.: Revisión de la estratigrafia de la Provincia de Pastora según el estudio de la región de Guasipati, Guayana venezolana. Bol. Geol. Caracas 10, 310–338 (1968)

    Google Scholar 

  • Menéndez, A.: Guia de la excursion geologica Guasipati el Callao-Canaima. Proc. Ninth Inter-Guayanas Geol. Conf. pp. 49–62 (1972)

  • Menéndez, A., Benaim, N., and Espejo, A.: Estratigrafica precámbrica de la provincia geologica de Pastora al este del Rio Caroni y su correlacion tentativa interguayana. Proc. Ninth Inter-Guayanas Geol. Conf. pp. 339–342 (1972)

  • Montgomery, C.P.W.: Uranium-lead isotopic investigation of the Archean Imataca Complex, Guayana Shield, Venezuela. Unpubl. Ph. D. thesis, M.I.T., 261 p. (1977)

  • Montgomery, C.W., Hurley, P.M.: Total-rock U-Pb and Rb-Sr systematics in the Imataca Series, Guayana Shield, Venezuela. Earth Planet. Sci. Lett. 39, 281–290 (1978)

    Google Scholar 

  • Moorbath, S., O'Nions, R.K., Pankhurst, R.J.: Early Archean age for the Isua Iron Formation, West Greenland. Nature 245, 138–139 (1973)

    Google Scholar 

  • Moorbath, S., Welke, H., Gale, N.H.: The significance of lead isotope studies in ancient high-grade metamorphic basement complexes, as exemplified by the Lewisian rocks of northwest Scotland. Earth Planet. Sci. Lett. 6, 245–256 (1969)

    Google Scholar 

  • Oversby, V.M.: Isotopic ages and geochemistry of Archean acid igneous rocks from the Pilbara, Western Australia. Geochim. Cosmochim. Acta 40, 817–829 (1976)

    Google Scholar 

  • Posadas, V.G., Kalliokoski, J.: Rb-Sr ages of the Encrucijada Granite intrusive in the Imataca Complex, Venezuela. Earth Planet. Sci. Lett. 2, 210–214 (1967)

    Google Scholar 

  • Quesada, A., Blackburn, W.H., Dennen, W.H., Lopez, V.W.: Composicion quimica y origen probable de las rocas del area de Guri. Geos. Central Univ. Caracas 18, 7–23 (1968)

    Google Scholar 

  • Ratmiroff, G. de: Origen y metamorfismo del paragneiss prinicpal del Complejo Precambrico de Imataca, cuadrilatero de Upata, Estado Bólivar, Venezuela. Bol. Geol. Caracas 7, 13 (1965)

    Google Scholar 

  • Richardson, K.A., Adams, J.A.S.: Effect of weathering on radioactive elements in the Conway Granite. Geol. Soc. Am. Spec. Paper 76, p. 137 (1964)

    Google Scholar 

  • Rios, J.H.F.: Geologia de la region Upata — El Palmar — Villa Lola. Proc. Ninth Inter-Guayanas Geol. Conf. pp. 354–371 (1972)

  • Rosholt, J.N., Zartman, R.E., Nkomo, I.T.: Lead isotope systematics and uranium depletion in the Granite Mountains, Wyoming. Bull. Geol. Soc. Amer. 84, 989–1002 (1973)

    Google Scholar 

  • Sighinolfi, G.P.: Investigations into deep crustal levels: fractionating effects and geochemical trends related to high grade metamorphism. Geochim. Cosmochim. Acta 35, 1005–1021 (1971)

    Google Scholar 

  • Stacey, J.S., Kramers, J.D.: Approximation of terrestrial lead isotopic evolution by a two-stage model. Earth Planet. Sci. Lett. 26, 207–221 (1975)

    Google Scholar 

  • Tatsumoto, M., Knight, R.J., Allègre, C.J.: Time differences in the formation of meteorites as determined from the ratio of lead-207 to lead-206. Science 180, 1279–1283 (1973)

    Google Scholar 

  • York, D.: Least-squares fitting of a straight line with correlated errors. Earth Planet. Sci. Lett. 5, 320–324 (1969)

    Google Scholar 

  • Zartman, R.E.: The isotopic composition of lead in microclines from the Llano Uplift, Texas. Geophys. Res. 70, 965–975 (1965)

    Google Scholar 

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Author notes

  1. Carla W. Montgomery

    Present address: Department of Geology, Northern Illinois University, 60115, DeKalb, IL, USA

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  1. Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, Massachusetts, USA

    Carla W. Montgomery

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  1. Carla W. Montgomery
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Montgomery, C.W. Uranium-lead geochronology of the Archean Imataca Series, Venezuelan Guayana Shield. Contr. Mineral. and Petrol. 69, 167–176 (1979). https://doi.org/10.1007/BF00371859

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