Record details

Title
    Re-Os geochemistry and geochronology of the Ransko gabbro-peridotite massif, Bohemian Massif
Author
    Ackerman, Lukáš
    Erban, Vojtěch
    Pašava, Jan
Language
    anglicky
Publication type
    článek v periodiku
Source title - serial
    Mineralium Deposita
Vol./nr.
    Roč. 48, č. 7
Pages
    6
Year
    2013
Thesaurus term
    Re-Os, Geochronology, Gabbro, Bohemian Massif, Ni-Cu mineralization
Keyword
    Bohemian
    Gabbro-peridotite
    Geochemistry
    Geochronology
    Massif
    Ransko
    Re-Os
Abstract (in english)
   The Ransko gabbro-peridotite massif in Eastern Bohemia is a strongly differentiated intrusive complex, which hosts low-grade Ni-Cu ores mainly developed close to the contact of olivine-rich rocks with gabbros, in troctolites, and to a much lesser extent in both pyroxene and olivine gabbros and plagioclase-rich peridotites. Gabbro, troctolite, peridotite and Ni-Cu ores from the Jezírka Ni-Cu (PGE) deposit, considered to be a typical example of the liquid segregation style of mineralization, were analyzed for Re-Os concentrations and isotopic ratios. Seven barren and mineralized samples fromthe Jezírka deposit yielded a Re-Os regression of 341.5?7.9 Ma (MSWD=69). Strongly mineralized peridotite with mantlelike initial 187Os/188Os ratio of 0.125 suggests that Os as well as other PGE present in the Ni-Cu mineralization are predominantly of mantle origin. On the other hand, barren and lowmineralized samples have radiogenic initial 187Os/188Os ratios of 0.14-0.16 suggesting some import of Re
    and/or radiogenic 187Os most likely through contamination by continental crust during magma emplacement. The Re-Os age of the Ransko Massif is significantly younger than the previously suggested Lower Cambrian age, but it is similar to and/or younger than the age of metamorphism of the adjacent Kutná Hora crystalline complex and the Moldanubian unit. Therefore, it is likely that the emplacement of the Ransko massif and its Ni-Cu mineralization was closely connected with the late-stage evolution of the Kutná Hora crystalline complex.
Contributor
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
    R
Import date
    15. 10. 2014