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

  • Ş. Nicolescu
  • D. H. Cornell
  • A.-V. Bojar
ARTICLE

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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Ş. Nicolescu
    • 1
  • D. H. Cornell
    • 1
  • A.-V. Bojar
    • 2
  1. 1.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: +46-31-7732849SE
  2. 2.Institut für Geologie und Paläontologie, Heinrichstraße 26, A-8010 Graz, Austria e-mail: bojar@balu.kfunigraz.ac.at, Fax: +43 316 3809870AT

Personalised recommendations