Search

Weathering processes cause significant changes in the engineering properties of rocks. Slope instability in flysch rock formations along the northern Adriatic coast of Croatia is related to the effects of weathering on the shear strength of siltstones from the flysch rock mass. Therefore, changes in geotechnical properties according to weathering grade are of immense importance in relation to instability processes. In this work, we investigated siltstones from flysch rock masses in the study area, and evaluated changes in engineering properties due to weathering. The research began with field observations and determination of the strength of different weathering grades of siltstones in the area. Mineralogical and laboratory studies were subsequently conducted, and mineral content was determined for siltstones of different weathering grades. We also performed a series of drying-wetting cycles to simulate natural conditions of the weathering process involved in the disintegration of the rock material into sand-sized and smaller particles. This weathering process resulted in disintegration of the siltstone rock mass into smaller particles that were not a unique rock block, with the soil-like material consisting of unbound particles of rock. Laboratory tests were also carried out on the soil-like material to determine the specific gravity, grain size distribution, Atterberg limits and residual shear strength for the different weathering grades of siltstones. Based on this research, we determined the changes in engineering properties for different weathering grades. Our results underscore the significant influence of the weathering process on mineral content, cation exchange capacity, liquid limit and residual shear strength, thus affecting slope stability in siltstones in flysch rock masses. [ABSTRACT FROM AUTHOR]

A soil geochemical survey of the city of Sisak, Croatia, and its surroundings was done to determine the concentration, spatial distribution and sources of the elements in the soil. Factor analysis indicates 8 factors describe the geochemical variations in the topsoil: 4 anthropogenic, 2 geogenic and 2mixed ones. The main influence in the urban and rural soils was parentmaterial and anthropogenic inputs in the old part of the city, along roads and railways, and in the industrial areas. The results indicate that soils are a very good media for accumulating trace elements in urban and industrial areas. [ABSTRACT FROM AUTHOR]

The objective of this work was to build a prognostic water flow model and potentially toxic elements (lead, cadmium, zinc) transport model in the unsaturated zone. Research was conducted in the catchment area of Kosnica regional wellfield, where the unsaturated zone is characterised by Fluvisol. Lower sorption capacities were determined in the first horizons for all three potentially toxic elements. Correlation coefficient of the measured and simulated values of tracer concentration is 0.58 for the AC horizon and 0.84 for the 2C/C1 horizon. Based on calibrated water flow and transport parameters, a prognostic water flow model and potentially toxic elements (lead, cadmium, zinc) transport model in the unsaturated zone was built. In case of an accidental spill of potentially toxic elements with concentrations of 1000 mg/l, the risk of contamination of the aquifer is present. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Canonical correlation analysis (CCA) is used in this study in order to trace the lineage of overbank sediment from the initial erosion of the parent rocks down to deposition of detrital material in alluvium of the small mountainous watersheds of the Žumberak area, Croatia. It helps to elucidate relations between the hierarchically structured systems (rocks, minerals, elements) represented by the ensembles of lithological, mineralogical and geochemical variables. Taking their place in the vertical order of hierarchical complexity, geochemistry and mineralogy of the recent material are considered dependent variable regarding the related watershed lithology, with geochemical variables (major and trace elements) last in the chain. Three canonical models are built and cross-compared in order to unravel the between-level relationships and infer the basic patterns of mineral and geochemical flux from the source rocks to basin. From these, the two hierarchical (provenance) chains epitomized in recombination of the first two canonical functions have been derived highlighting complementary provenances, weathering styles, and dispersion avenues in alluvial sedimentation of the study area. The first clearly separates carbonate from siliciclastic sedimentary source while the second illuminates the origin of phyllosilicate and ferric oxyhydroxide phases with associated suite of elements in absence of clear carbonate signal. [ABSTRACT FROM AUTHOR]