Naslov
Formation mechanisms of Fe-Mn concretions in the Vijenac Quarry, Dinaric Ophiolite Zone

Autori
Bevandić, Srećko ; Brenko, Tomislav ; Babajić, Elvir ; Borojević Šoštarić, Sibila

Izvornik
Rudarsko-geološko-naftni zbornik (0353-4529) 33 (2018), 3; 63-74

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Fe-Mn concretions ; diagenetic growth ; Mn-minerals ; chemical analysis ; Dinaric Ophiolite Zone

Sažetak
The Vijenac limestone quarry, near Tuzla in Bosnia and Herzegovina, is composed of carbonate rocks locally embedding tectonically disturbed siltite and sandstone with Fe-Mn concretions. The quarry itself represents a part of Dinaric overstep sequences (the Pogari Formation) unconformably overlying ophiolite mélange and ophiolite trust-scheets. Petrographic, chemical and mineralogical analyses had shown that the concretions may be divided into two types: (i) Mn-rich concretions with ≈ 17 wt.% of Mn and compact texture and (ii) Mn–poor with ≈ 8 wt.% of Mn and porous texture. The amount of Ca, Fe and Mg in both concretion types are similar. Nickel and Cr positively correlate with Fe and Mn, respectively. According to petrographic and mineralogical analyses, concretions are composed of calcite, dolomite, hematite, todorokite and takanelite. Petrographic study confi rmed the development of concretions within three stages including two generations of calcite. Studied concretions are formed within consolidated sandstones inheriting their sedimentary textures – therefore a late diagenetic process is assumed.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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