Mineralium Deposita

, Volume 34, Issue 8, pp 743–753

Age and tectonic setting of Bocşa and Ocna de Fier – Dognecea granodiorites (southwest Romania) and of associated skarn mineralisation

Authors

  • Ş. Nicolescu
    • Geology Department, Earth Sciences Centre, University of Gothenburg, Box 460, SE – 405 30 Gothenburg, Sweden e-mail: Stefan.Nicolescu@gvc.gu.se, Fax: +46-31-7732849, e-mail: Cornell@geo.gu.se, Fax: +46-31-7732849
  • D. H. Cornell
    • Geology Department, Earth Sciences Centre, University of Gothenburg, Box 460, SE – 405 30 Gothenburg, Sweden e-mail: Stefan.Nicolescu@gvc.gu.se, Fax: +46-31-7732849, e-mail: Cornell@geo.gu.se, Fax: +46-31-7732849
  • A.-V. Bojar
    • Institut für Geologie und Paläontologie, Heinrichstraße 26, A-8010 Graz, Austria e-mail: bojar@balu.kfunigraz.ac.at, Fax: +43 316 3809870
ARTICLE

DOI: 10.1007/s001260050235

Cite this article as:
Nicolescu, Ş., Cornell, D. & Bojar, A. Mineral. Deposita (1999) 34: 743. doi:10.1007/s001260050235

Abstract

The granodiorite intrusion at Ocna de Fier-Dognecea in the western South Carpathians, Romania, triggered the formation of a classic Fe-(Pb-Zn) skarn deposit. The intrusive is related to the larger composite Bocşa Laccolith five kilometres north that is part of the regional Banatite Suite. Previous work indicated a K/Ar age of 65–57 Ma and postulated an Andean-type subduction related tectonic setting for the intrusions. We report ion probe U/Pb zircon ages of 79.6 ± 2.5 Ma for the Bocşa Laccolith and 75.5 ± 1.6 Ma for the Ocna de Fier Pluton, which date their emplacement. Fission track dating on titanite gives slightly younger ages: 78 ± 4 Ma for Bocşa and 73 ± 4 Ma for Ocna de Fier. Together with zircon and apatite data from the same samples, average cooling rates of 52 °C/Ma and 83 °C/Ma are calculated for the Bocşa and Ocna de Fier intrusives respectively. A post-collision tectonic setting is proposed on the basis of field evidence, the timing of intrusions in the context of regional tectonic evolution, and trace element geochemistry.

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© Springer-Verlag Berlin Heidelberg 1999