Genesis of the Urals VHMS deposits inferred from coupled Pb-Os isotope systematics

Svetlana G. Tessalina*, Jean Jacques Orgeval

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

    Abstract

    Coupled Pb-Os isotope systematics were studied within ore facies, host rocks and sediments from the Paleozoic VHMS deposits in Southern Urals, Russia.

    Lead isotope composition becomes progressively more radiogenic from early fore-arc environments to intra-arc and back-arc settings, which can be explained in terms of metasomatism of the depleted mantle wedge in the Ordovician - Early Devonian due to subduction of sediments and continental fragments. A metasomatized mantle wedge signature is expressed in LREE enrichment and low epsilon(Nd) values.

    Os and other PGEs are enriched in first-stage high-temperature portions of hydrothermal systems, whereas Re has more affinity with lower temperature polymetallic assemblages. In each deposit, the Re/Os ratio and initial (187)OS/(188)Os isotopic compositions in ores decrease from the bottom to the top of hydrothermal system, reflecting variable degrees of mixing between hydrothermal fluid and Devonian seawater.

    The Re-Os model ages for four studied deposits from different tectonic settings are similar (about 366 +/- 5 Ma) and younger than the presumed stratigraphic ages. This age could indicate a late Os isotope reequilibration associated with long living hydrothermal processes attending formation and closure of the Urals paleo-ocean in a Late Devonian time.

    Original languageEnglish
    Title of host publicationSmart science for exploration and mining
    EditorsPJ Williams
    Place of PublicationTownsville, QLD
    PublisherJAMES COOK UNIV
    Pages263-265
    Number of pages3
    ISBN (Print)9780980558685
    Publication statusPublished - 2010
    Event10th Biennial SGA Meeting of the Society for Geology Applied to Mineral Deposits - Townsville, Australia
    Duration: 17 Aug 200920 Aug 2009

    Conference

    Conference10th Biennial SGA Meeting of the Society for Geology Applied to Mineral Deposits
    CountryAustralia
    CityTownsville
    Period17/08/0920/08/09

    Keywords

    • Massive sulphide deposits
    • Urals
    • isotope systematics
    • Pb
    • Os
    • MASSIVE SULFIDE DEPOSITS
    • SOUTH URALS
    • CONSTRAINTS
    • OROGEN

    Cite this

    Tessalina, S. G., & Orgeval, J. J. (2010). Genesis of the Urals VHMS deposits inferred from coupled Pb-Os isotope systematics. In PJ. Williams (Ed.), Smart science for exploration and mining (pp. 263-265). Townsville, QLD: JAMES COOK UNIV.