Central European Journal of Geosciences

, Volume 2, Issue 3, pp 321–328 | Cite as

Note on the evolution of a Miocene composite volcano in an extensional setting, Zârand Basin (Apuseni Mts., Romania)

  • Ioan Seghedi
  • Alexandru Szakács
  • Emilian Roşu
  • Zoltán Pécskay
  • Katalin Gméling


Bontâu is a major eroded composite volcano filling the Miocene Zârand extensional basin, near the junction between the Codru-Moma and Highiş-Drocea Mountains, at the tectonic boundary between the South and North Apuseni Mountains. It is a quasi-symmetric structure (16–18 km in diameter) centered on an eroded vent area (9×4 km), buttressed to the south against Mesozoic ophiolites and sedimentary deposits of the South Apuseni Mountains. The volcano was built up in two sub-aerial phases (14–12.5 Ma and 11–10 Ma) from successive eruptions of andesite lava and pyroclastic rocks with a time-increasing volatile budget. The initial phase was dominated by emplacement of pyroxene andesite and resulted in scattered individual volcanic lava domes associated marginally with lava flows and/or pyroclastic block-and-ash flows. The second phase is characterized by amphibole-pyroxene andesite as a succession of pyroclastic eruptions (varying from strombolian to subplinian type) and extrusion of volcanic domes that resulted in the formation of a central vent area. Numerous debris flow deposits accumulated at the periphery of primary pyroclastic deposits. Several intrusive andesitic-dioritic bodies and associated hydrothermal and mineralization processes are known in the volcano vent complex area. Distal epiclastic deposits initially as gravity mass flows and then as alluvial volcaniclastic and terrestrial detritic and coal filled the basin around the volcano in its western and eastern part.

Chemical analyses show that lavas are calc-alkaline andesites with SiO2 ranging from 56–61%. The petrographical differences between the two stages are an increase in amphibole content at the expense of two pyroxenes (augite and hypersthene) in the second stage of eruption; CaO and MgO contents decrease with increasing SiO2. In spite of a ∼4 Ma evolution, the compositions of calc-alkaline lavas suggest similar fractionation processes. The extensional setting favored two pulses of short-lived magma chamber processes.


composite volcano Apuseni Mountains andesite extensional setting 


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  1. [1]
    Roşu E., Seghedi I., Downes H., Alderton D.H.M., Szakács A., Pécskay Z., Panaiotu C., Panaiotu C.E., Nedelcu L., Extension-related Miocene calc-alkaline magmatism in the Apuseni Mountains, Romania: origin of magmas. Swiss Bulletin of Mineralogy and Petrology, 2004, 84/1-2, 153–172Google Scholar
  2. [2]
    Pécskay Z., Edelstein O., Seghedi I., Szakács A., Kovacs M., Crihan M., Bernad A., K-Ar datings of the Neogene-Quaternary calc-alkaline volcanic rocks in Romania. Acta Vulcanologica, 1995, 7, 53–63Google Scholar
  3. [3]
    Roşu E., Pécskay Z., Stefan A., Popescu G., Panaiotu C., Panaiotu C.E., The evolution of the Neogene volcanism in the Apuseni Mountains (Romania): constraints from new K/Ar data. Geologica Carpathica, 1997, 48, 6, 353–359Google Scholar
  4. [4]
    Sândulescu M., Cenozoic tectonic history of the Carpathians. In: The Pannonian Basin: A study in Basin evolution. L. Royden & F. Horvath (Eds.), AAPG Memoir, 45, 1988, 17–25Google Scholar
  5. [5]
    Dallmeyer R.D., Panâ D.I., Neibauer F., Erdmer P., Tectonothermal evolution of the Apuseni Mountains, Romania: Resolution of Variscan versus Alpine events with 40 Ar/39 Ar ages: J. Geol., 1999, 107, 329–352CrossRefGoogle Scholar
  6. [6]
    Panâ D.I., Heaman L.M., Creaser R.A., Erdmer P., Pre-Alpine Crust in the Apuseni Mountains, Romania: Insights from Sm-Nd and U-Pb Data. J. Geol., 2002, 110, 341–354CrossRefGoogle Scholar
  7. [7]
    Royden L.H., Late Cenozoic tectonics of the Pannonian basin system. In: The Pannonian Basin: A study in Basin evolution, L. Royden & F. Horvath (eds.), AAPG Memoir, 45, 1988, 27–48Google Scholar
  8. [8]
    Csontos L., Márton E., Worum G., Benkovics I., Geodynamics of SW-Pannonian inselberg (Mecsek and Villany Mts., SW Hungary): inference from complex structural analysis, EGU Müller Special Pub., Ser. 3, 2002, 1–19Google Scholar
  9. [9]
    Seghedi I., Balintoni I., Szakács A., Interplay of tectonics and Neogene post-collisional magmatism in the Intracarpathian area. Lithos, 1998, 45, 483–499CrossRefGoogle Scholar
  10. [10]
    Seghedi I., Downes H., Szakács A., Mason P.R.D., Thirlwall M.F., Rosu E., Pécskay Z., Marton E., Panaiotu C., Neogene-Quaternary magmatism and geodynamics in the Carpathian-Pannonian region: a synthesis. Lithos, 2004, 72, 117–146CrossRefGoogle Scholar
  11. [11]
    Seghedi I., Bojar A.-V., Downes H., Rosu E., Tonarini S., Mason P.R.D., Generation of normal and adakitelike calc-alkaline magmas in a non-subductional environment: A Sr-O-H isotopic study of the Apuseni Mountains Neogene magmatic province, Romania. Chemical Geology, 2007, 245, 70–88CrossRefGoogle Scholar
  12. [12]
    Tari G., Dovenyi P., Dunkl I., Horvath F., Lenkey L., Ştefanescu M., Szafian P. and Toth T., Lithospheric structure of the Pannonian basin derived from seismic, gravity and geothermal data. In: Durand B., Jolivet L., Horvath F. and Serrane M. (Editors), The Mediterranean Basins: extension within the Alpine Orogen. Geol. Soc. London Spec. Publ., 156, 1999, 215–250Google Scholar
  13. [13]
    Ianovici V., Giusca D., Ghiţulescu T.P., Borcoş M., Lupu M., Bleahu M. and Savu H., Geological evolution of the Metaliferi Mountains Ed. Acad. Rep. Soc. Romania, 741 pp (in Romanian), 1969Google Scholar
  14. [14]
    Istocescu D., Geological study of the western part of the Crişul Alb valley and Codru and Highis border. St. Tehn. Econom. Series J, 1971, 8, pp.201 (in Romanian)Google Scholar
  15. [15]
    Savu H. and Neacsu Gh., Neogene volcanism in the Zârand basin. D. S. Com. Geol. 1962, XLVIII, 345–360, Bucharest (in Romanian with Russian and French abstract)Google Scholar
  16. [16]
    Berbeleac I., David M. and Zâmârcâ A., Petrological and petrochemical data on the Tertiary volcanics from the eastern part of the Zaarand Mountains. D.S. Inst. Geol. Geofiz., 1984, LXVIII (1981), 27–46Google Scholar
  17. [17]
    Berbeleac I., Neacsu V., Zâmârcâ A., Bratosin I., Geochemistry and mineralogy of altered rocks and pyrites associated with the porphyry copper-gold mineralization of the Tertiary subvolcanic from Talagiu, Zârand Mountains. Rom. J. Mineral Deposits, 1992, 75, 55–64Google Scholar
  18. [18]
    Berbeleac I., Iliescu D., Andrei J., Ciuculescu O., Ciuculescu R., Relationships between alterations, porphyry copper-gold and base metal-gold hydrothermal vein mineralizations in Tertiary intrusions, Talagiu area, Zârand Mountains. Rom. J. Mineral Deposits, 1995, 76, 31–39Google Scholar
  19. [19]
    Freundt A., Wilson C.J.N., Carey S.N., Ignimbrites and block-and-ash deposits. In: Sigurdsson H., Houghton B.F., McNutt S.R., Rymer H., Stix J. (Eds.), Encyclopedia of Volcanoes, Academic Press, San Diego, 2000, 581–601Google Scholar
  20. [20]
    Davidson J., De Silva S., Composite volcanoes. In: Sigurdsson H., Houghton B.F., McNutt S.R., Rymer H., Stix J. (Eds.), Encyclopedia of Volcanoes, Academic Press, San Diego, 2000, 663–683Google Scholar
  21. [21]
    Sagatovici A., Anastasiu N., The study of pyroclas-tic rocks from Minişul de sus (Bazinul Zârandului). Analele Universitatii Bucuresti, Geologie, 1972, XXI, 31–40 (in Romanian)Google Scholar
  22. [22]
    Morrissey M.M., Mastin L.G., Vulcanian eruptions. In: Sigurdsson, H., Houghton, B.F., McNutt, S.R., Rymer, H., Stix, J. (Eds.), Encyclopedia of Volcanoes, Academic Press, San Diego, 2000, 463–467Google Scholar
  23. [23]
    Szakâcs A., Redefining active volcanoes: a discussion. Bulletin of Volcanology, 1994, 56, 321–325CrossRefGoogle Scholar
  24. [24]
    Belgya T., Révay Zs., Gamma-ray spectrometry. In Molnár, G.L.: Handbook of prompt gamma activation analysis with neutron beams. Kluwer Academic Publisher, 2004, 71–111Google Scholar
  25. [25]
    Révay Zs., Belgya T., Ember P.P., Molnár G.L., Recent Developments in Hypermet-PC. J. Radioanal. Nucl. Chem., 2001, 248, 401–405CrossRefGoogle Scholar
  26. [26]
    Révay Zs. Determining Elemental Composition Using Prompt Gamma Activation Analysis, Anal. Chem., 2009, 81, 6851–6859CrossRefGoogle Scholar
  27. [27]
    Balogh K., K-Ar dating of Neogene volcanic activity in Hungary. Experimental technique, experiences and methods of chronological studies. ATOMKI Reports 1985, D/1, 277–288Google Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Ioan Seghedi
    • 1
  • Alexandru Szakács
    • 1
    • 2
  • Emilian Roşu
    • 3
  • Zoltán Pécskay
    • 4
  • Katalin Gméling
    • 5
  1. 1.Institute of GeodynamicsBucharestRomania
  2. 2.Dept. of Environmental SciencesSapienμia UniversityCluj-NapocaRomania
  3. 3.Geological Institute of RomaniaBucharestRomania
  4. 4.Institute of Nuclear Research of the Hungarian Academy of SciencesDebrecenHungary
  5. 5.Hungarian Academy of SciencesInstitute of IsotopesBudapestHungary

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