Naslov
Mineralogical and geochemical characteristics of the Upper Miocene pelitic sediments of Hrvatsko Zagorje

Autori
Grizelj, Anita ; Tibljaš, Darko ; Kovačić, Marijan

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

Izvornik
3. Hrvatski geološki kongres, Knjiga sažetaka / Ivo Velić, Igor Vlahović & Ranko Biondić - Zagreb : Hrvatski geološki institut, 2005, 47-48

Skup
3. Hrvatski geološki kongres

Mjesto i datum
Opatija, Hrvatska, 29.09.2005. - 01.10.2005

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
pelitic sediments; Late Pannonian; Early Pontian; X-ray diffraction; Pannonian Basin

Sažetak
Mineralogical and geochemical investigations of the Late Pannonian and Early Pontian pelitic deposits were performed on samples from two outcrops from southwestern part of Hrvatsko Zagorje located near villages Pušća and Kupljenski Hruševec. Mineralogical investigations included qualitative and quantitative X-ray diffraction analysis (XRD) on insoluble rock residue and <2 &#956; m fraction of this residue. The X-ray diffraction analysis was performed on randomly orientated and orientated aggregates of air-dried material, material treated with ethylen-glycol for at least 4 hours by vapor pressure method, material heated to 400&#186; C and 550&#186; C for at least 30 minutes, and insoluble residue obtained after boiling in 2N hydrochloric acid for 30 minutes. Modal analysis of 0.045 to 0.16 mm fraction was done on polarizing microscope. Chemical analyses were made by ICP-AES for major elements and ICP-MS for trace elements in ACME Analytical Laboratories LTD, Vancouver, Canada. The content of CaCO3 was determined by EDTA titration. The composition of insoluble rock residue, as determined by XRD analysis, shows that all rocks have the same mineral assemblages but the proportions of clay minerals and other phases like calcite, quartz and feldspars vary considerably. Dominant minerals in investigated rocks are calcite (31-74%), quartz (5-21%), feldspars (1-5%) and clay minerals (18-50%). Some samples also contain dolomite and pyrite (table 1). In the < 2&#956; m fraction of insoluble rock residue smectite, illite and chlorite were determined, while the presence of kaolinite was not established unambiguously. Observed mineral composition of marls is in accordance with the results for Miocene pelitic sediments of the Hungarian part of Pannonian Basin and clay minerals (illite, smectite, chlorite and kaolinite?) are essentially detrital. Dominant constituents in silt size fraction are quartz, feldspars, rock fragments (chert, quartzite and schists) and micas. Chlorite, limonite, pyrite, garnet, tourmaline, zircon, epidote and staurolite are present in small amounts. Observed differences in chemical composition of analyzed rocks are primarily due to changes in proportions of silt and clay fractions. According to mineral content of insoluble rock residue and CaCO3 content, Late Pannonian pelitic samples can be mainly classified as marls and Early Pontian samples as silty marls. Observed gradual decrease of carbonate content and simultaneous increase of clay and silt content from Late Pannonian to Early Pontian pelitic deposits are results of increasing terrigenous influence resulting from progradation of clastic systems in the south - south - eastern direction Direction of this progradation as well as mineral composition of silt size fraction suggest Alpine provenance.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA