Naslov
Mineralogical characteristics of Sarmatian tuffs from Bukova Glava locality, Mt. Krndija (NE Croatia)

Autori
Marković, Frane ; Šušnjar, Stella ; Kovačić, Marijan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, prošireni sažetak, znanstveni

Izvornik
Special Issue of Journal of Faculty of Mining, Geology and Civil Engineering / Dervišević, Rejhana ; Vrabac, Sejfudin ; Babajić, Elvir ; Đulović, Izudin - Tuzla : University of Tuzla, Faculty of Mining, Geology and Civil Engineering, 2022, 45-46

Skup
9th International Workshop Neogene of Central and South-Eastern Europe

Mjesto i datum
Tuzla, Bosna i Hercegovina, 06.06.2022. - 09.06.2022

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Tuffs, Sarmatian, Bukova Glava

Sažetak
On the northern slopes of Mt. Krndija, 5 km south-west from the town of Našice, a large quarry owned by “NEXE d.d.” is in use for cement production. Two different sections are in use, Bukova Glava in the southern part and Vranović in the northern part of the quarry. The studied section Bukova Glava comprises mainly carbonate rocks of Middle Miocene age (PAVELIĆ et al. 2003 ; ZEČEVIĆ et al. 2010 ; KOVAČIĆ et al. 2015b) and subordinate pyroclastic rocks i.e. tuffs (KOVAČIĆ et al., 2017b ; OLIĆ et al. 2019). Four main facies have been determined: algal limestones, biocalcarenites/biocalcirudites, marls and pyroclastics. Deposition took place in a marine environment which gradually changed from fully marine environment (Upper Badenian) to a marine environment with reduced salinity (Sarmatian) (KOVAČIĆ et al. 2015b, ĆORIĆ et al. 2017). In the middle part of the approximately 100 meter thick section, above the Badenian/Sarmatian boundary three layers of altered tuff, few centimetres thick have been sampled (sample codes: 34/1 ; 55/1 and 77/1). Analyses of granulometric composition, carbonate content, modal composition of the heavy mineral fraction and X-ray analysis have been carried out. Mean particle size of the analysed samples ranges from 3.5 to 10.6 μm. Even though all three samples are predominantly composed of particles smaller than 63 μm, large quantity of the samples has been sieved and modal analysis of the 63 – 125 μm fraction has been carried out. Heavy mineral concentration ranges from 0.01 to 0.40%. Carbonate content ranges from 2.1 to 4.1% in samples analysed. The light mineral fraction (< 2.90 g/cm3) consists of devitrified glass, sanidine, plagioclase, muscovite, quartz and gypsum. The occurrence of gypsum may indicate the primary presence of sulfides whose oxidation could have led to the formation of secondary sulfate minerals (ZIMBELMAN et al., 2005). The concentration of transparent heavy minerals is ~70% while the remainder consists of opaque minerals and phyllosilicates. Sample 34/1 is dominated by barite while zircon is less represented. Barite is formed almost exclusively in microenvironments containing decaying organic matter and the remains of siliceous plankton (BISHOP, 1988) and is here considered as a secondary mineral. Sample 55/1 entirely consist of jarosite which is also secondary mineral formed by oxidation of sulfides. Sample 77/1 is dominated by epidote, clinozoiste, zoisite and less represented garnet and apatite. This heavy mineral assemblage indicates a weak terrigenous input. Clay minerals from the smectite group have been identified by X-ray diffraction analysis. These preliminary results suggest that smectites were formed by devitrification of volcanic glass. The main focus of the future research should be determination of the absolute age of tuffs along with determination of calcareous nannofossil and foraminiferal assemblages of immediate underlying and overlying marls of the tuffs.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA