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Mineralium Deposita

, Volume 37, Issue 6–7, pp 630–647 | Cite as

Fluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner Carpathians, Romania

  • Luminita Grancea
  • Laurent Bailly
  • Jacques Leroy
  • David Banks
  • Eric Marcoux
  • Jean Milési
  • Michel Cuney
  • Anne André
  • Dumitru Istvan
  • Cécile Fabre
Article

Abstract.

The Baia Mare district (Romania) represents a complex segment of the Neogene/Quaternary, subduction-related, volcanic chain of the Carpathians. In this province, the calc-alkaline volcanism and associated mineralization are closely related to a major strike-slip fault and an underlying pluton. The ore deposits of the district have many features typical of low-sulfidation (or adularia-sericite) epithermal deposits. The combination of fluid-inclusion microthermometry, Raman spectroscopy, bulk crush-leach analysis, laser ablation-optical emission spectrometry (LA-OES) of individual fluid inclusions and stable isotope data has been used to characterize the ore-forming solutions involved with gold/polymetallic mineralization in three of the largest deposits. Ore fluids at Baia Sprie, Cavnic and Sasar deposits had temperatures of 320 to 150 °C and salinities in the range 0–21 wt% NaCl equiv. During phreatomagmatic activity, fracturing and periods of vein dilation, the pressure fluctuations may have caused boiling. The hydrothermal fluids were Na–K–Li–Ca chloride solutions with lesser amounts of SO4 and F. The Na/K ratios and the stable isotope compositions are consistent with equilibration of the fluids with country rocks at progressively lower temperatures. The halogen ratios (Br/Cl×103 in the range 0.13–1.21), together with sulfur isotopic systematics (δ34S=0.3–5.2 per mil), are consistent with a dominantly magmatic origin of the solutes, and probably of the ore fluids themselves.

Epithermal mineralization Fluid Carpathians Magmatism 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Luminita Grancea
    • 1
  • Laurent Bailly
    • 2
  • Jacques Leroy
    • 1
  • David Banks
    • 3
  • Eric Marcoux
    • 4
  • Jean Milési
    • 2
  • Michel Cuney
    • 1
  • Anne André
    • 1
  • Dumitru Istvan
    • 5
  • Cécile Fabre
    • 1
  1. 1.UMR G2R, Université Henri Poincaré, BP 239, 54506 Vandoeuvre-lès-Nancy cedexFrance
  2. 2.BRGM, REM/MESY, BP 6009, 45060 Orléans cedex 2France
  3. 3.School of Earth Sciences, Leeds University, LS29JTUK
  4. 4.ISTO, Université d'Orléans, ESEM, 45072 Orléans cedex 2France
  5. 5.IPEG Maramures, Victoriei 146, Baia Mare 4800Romania

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