Chemical composition of Kiscellian silty sediment (sivica) from the Trobni Dol area, Eastern Slovenia

Kiscellian marine silt termed »sivica« is widely developed in Tertiary basins of Eastern Slovenia. Chemical composition is rather uniform and reflects the dominance of filosilicates (mainly illite/muscovite, chlorite and montmorillonite) and carbonates. PAAS normalised REE and Y abundances are slightly depleted for La, Ce, Pr and Nd, very close to PAAS for Sm, Eu, Gd and Tb, and depleted for Y, Ho, Er, Tm, Yb and Lu

Relationship between the undrained shear strength, water content, and mineralogical properties of fine-grained soils

The relationship between the undrained shear strength of fine-grained soils and the water content can be described with a nonlinear function in which the type of soil is determined by two parameters. It is well known that these parameters depend mainly on the mineral compositions of soilsč these relationships, however, have not yet been investigated. The findings describedin this paper define those mineralogical properties of soils which determine the values of both parameters. Experimentally obtained results suggest that the parameters primarily depend on the size of the clay minerals,their quantity in soil composition, and the interlayer water quantityin the expanding clay minerals. As this dependence is well defined, the parameters, and thus the undrained shear strength at different water content, can be defined from knowledge of these mineralogical soil properties

Correlation between surface area and Atterberg limits of fine-grained soils

As the water content is increased, the consistency of a fine-grained soil changes from a semi-solid state to a plastic state and finally to a liquid state. The plastic limit (PL) is the point at which the consistency, caused by the soil water content, is transformed from a semi-solid state to a plastic state. The liquid limit (LL) is the point at which the consistency is transformed from a plastic state to a liquid state. The plastic limit and liquid limit are often collectively referred to as the Atterberg (or consistency) Limits. Although the liquid and plastic limits are easily determined, fundamental interpretations of the limits and quantitative relationships between their values and compositional factors are more complex. Previous studies examined artificially-prepared soil samples that contained monomineralic clays and a non-clay substance (quartz sand). These studies have shown that in soils without expandable clays the PL and LL water contents were mostly related to surface area and clay content. For soils that contain expandable clays, the PL and LL values are also dependent on interlayer water content. Hence, expandable clay mineral contents are needed to calculate PL and LL values. These relationships have been presented in a general analytical form. The aim of these investigations was to identify practical applications. Mineral compositions and surface areas of five randomly selected natural soil samples were used to estimate PL and LL values. The estimated values were compared to experimentally measured liquid limits (by the 'fallcone' test) and plastic limit (by the 'rolling thread' test) values. The measured PL values ranged from 18.77 to 44.92% and the LL values from 31.19 to 82.10%. The differences between estimated and measured Atterberg Limits were 3.0-7.1 % for the PL and 2.7-7.8% for the LL. Minor differences in measured and estimated Atterberg Limits were probably due to soil organic matter (1.2-2.7%)

Lithology of Tertiary beds in Kozjansko, Eastern Slovenia

Oligocene and Miocene beds in Kozjansko, SW part of the Parathetys region, were developed in the time span ranging from Kiscellian to Pannonian, with two emersion phases – the first in Ottnangian, Karpatian and partially Badenian, and the second in Badenian and Sarmatian. Kiscellian sedimentation started with basal conglomerate, which was followed by sand, marl with coal seams, and marly clay (sivica). Clastic sedimentation was accompanied by volcanic activity that produced andesites, dacites, and andesitic,dacitic and rhyolitic tuffs. Egerian deposits include sands, sandstones, siltstones, claystones,marls and tuffs (the Govce beds). Eggenburgian deposits are characterised by quartztoze and gluconitic sandstones (the Macelj sandstones) and conglomerates. Badenian deposits are among the most widespread in occurrence and the most diverse in development. Theyare known as the Laško beds. Marls and siltstones predominate over massive lithothamnian limestone, calcareous-quartztoze conglomerate and biocalcarenite. They contain marine fauna. Badenian tuffs have been newly discovered on the territory of Kozjansko. InSarmatian, the environment changed from marine to brakish and freshwater. Transgressively deposited conglomerate is overlain by sand, marl, sandstone and scarce beds of marly limestone. Clastic sedimentation continued in the Pannonian time, too