Mechanisms for formation of the Mn–Fe concretions within Vijenac quarry, Dinaridic ophiolite melange

Authors

  • Srećko Bevandić Faculty of Mining, Geology and Petrolium engineering, Zagreb
  • Tomislav Brenko Faculty of Mining, Geology and Petrolium engineering, Zagreb
  • Elvir Babajic Faculty of Mining, Geology and Civil Engineering, Tuzla
  • Sibila Borojević Šoštarić Faculty of Mining, Geology and Petrolium engineering, Zagreb

DOI:

https://doi.org/10.17794/rgn.2018.3.7

Keywords:

Fe-Mn concretions, diagenetic growth, Mn-minerals, chemical analysis, Dinaric Ophiolite Zone

Abstract

Vijenac quarry, near Tuzla in Bosnia-Herzegovina, is composed of carbonate rocks locally embedding tectonically disturbed siltite and sandstone with Mn-Fe concretions. The quarry itself represent a part of Dinaric overstep sequences (Pogari series) unconformably overlying ophiolite mélange and ophiolite trust-scheets. Petrographic, chemical and XRD analyses had shown that the concretions may be divided into two types: (i) Mn-rich concretions with ≈17% of Mn and compact texture and (ii) Mn-poor (≈8% of Mn) and porous texture. The amount of Ca, Mg, Fe and organic matter, as well as analysed microelements (Ni, Cr) in both concretion types are similar. According to petrographic and XRD analyses, concretions are composed of calcite, dolomite, hematite, todorkite and takenelite. Todorokite is characteristic for concretions formed by diagenetic growth. Petrographic study confirmed the development of concretions within three stages including two generations of calcite. The studied concretions are formed within consolidated sandstones inheriting their sedimentary textures - therefore a late diagenetic process is assumed.

Author Biographies

  • Srećko Bevandić, Faculty of Mining, Geology and Petrolium engineering, Zagreb
    student
  • Tomislav Brenko, Faculty of Mining, Geology and Petrolium engineering, Zagreb
    assistent
  • Elvir Babajic, Faculty of Mining, Geology and Civil Engineering, Tuzla

    Asst. Prof., PhD

     

  • Sibila Borojević Šoštarić, Faculty of Mining, Geology and Petrolium engineering, Zagreb
    Assoc. Prof., PhD

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Published

2018-06-01

Issue

Section

Geology

How to Cite

Mechanisms for formation of the Mn–Fe concretions within Vijenac quarry, Dinaridic ophiolite melange. (2018). Rudarsko-geološko-Naftni Zbornik, 33(3), 63-74. https://doi.org/10.17794/rgn.2018.3.7

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