Record details

Title
    Laser-ablation ICP-MS measurements of Re/Os in molybdenite and implications for Re-Os geochronology
Statement of responsibility
    Jan Košler, Antonio Simonetti, Paul J. Sylvester, Richard A. Cox, Michael N. Tubrett, Derek H.C. Wilton
Author
    Cox, Richard A.
    Košler, Jan, 1965-
    Simonetti, Antonio
    Sylvester, Paul J.
    Tubrett, Michael N.
    Wilton, Derek H. C.
Language
    anglicky
Source title - serial
    Canadian mineralogist
Vol./nr.
    Vol. 41, no. 2
Pages
    p. 307-320
Year
    2003
Notes
    1 fot., 6 diagr., 1 tab., 2 s. bibl.
    Francouzské resumé
    il.
    Zkr. název ser.: Canad. Mineralogist
Subject group
    datování Re/Os
    krystalinikum Českého masivu
    metoda ICP
    metoda laserová
    molybdenit
    rudy Au
    spektrometrie hmotnostní
Geographical name
    Bělčice (Strakonice)
    ČR-Čechy
    Kanada-Quebec
    Kašperské Hory (Klatovy)
    Mokrsko (Příbram)
Keyword
    Geochronology
    ICP-MS
    Implications
    Laser-ablation
    Measurements
    Molybdenite
    Re-Os
    Re/Os
Abstract (in english)
   Laser-ablation quadrupole ICP-MS analyses of molybdenite samples from Preissac, Quebec, and Mokrsko, Bělčice and Kašperské Hory gold deposits in the Bohemian Massif, Czech Republic, for Re and radiogenic l87Os suggest the presence of strong zoning in Re and in l87Os/187Re values within grains. The zoning patterns indicate decoupling of daughter l87Os from parent 187Re after molybdenite crystallization. Whereas Re is not homogeneously distributed in the molybdenite grains studied, the lack of correlation between the calculated 87Os/187Re value and the Re content also reflects the mobility of l87Os within individual grains of molybdenite. Such decoupling of Re and Os could affect the accuracy of Re-Os ages if disturbed portions of molybdenite are sampled for dating by conventional isotope-dilution N-TIMS or ICP-MS techniques.
   The results re-emphasize the critical need for homogenization of quantities of molybdenite sufficiently large to capture the bulk Os/Re of the sample to be dated by these methods. Laser-ablation sampling, when used with a multicollector magnetic-sector ICP-MS instrument, is able to produce Re-Os ages with a precision better than 2 per cent (1 "sigma" m)from single spots in certain old and Re-rich molybdenite grains, but would be difficult to use as a dating tool given the extreme 187Os/187Re heterogeneity seen in individual grains
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    26. 9. 2007
Import date
    8. 8. 2012