| Abstract [eng] |
Till sediments are the most widespread in Lithuania and they are most commonly used in human economic activities. Both in Lithuania and globally, there have not been many detailed studies and comparisons of the mineralogical and chemical composition as well as the physical properties of till soils. The aim of this study is to identify the differences between the mineralogical, chemical and granulometric composition and plasticity of fine-grained till soils from the Upper Pleistocene Nemunas Formation Baltija Subformation and the Middle Pleistocene Žeimena Formation Medininkai Subformation, and to compare these results with global literature. A total of 40 samples from various locations across Lithuania were collected and prepared for analysis. The mineralogical composition was determined using X-ray diffraction (XRD), while the chemical composition was analysed using atomic absorption spectroscopy (AAS). The study revealed that the Middle Pleistocene sediments are characterised by higher sand content, lower plasticity and lower moisture content compared to the Upper Pleistocene till deposits. In addition, the fine fraction of till sediments from the Medininkai Subformation contains more carbonate minerals, whereas the other detected minerals are the same. The chemical composition of the deposits is diverse – the Žeimena Formation Medininkai Subformation sediments contain higher amounts of lead, strontium, magnesium and calcium, which are associated with a higher amount of carbonate minerals, while the Nemunas Formation Baltija Subformation till soil contains slightly higher levels of copper, which is due to higher clay content. A comparison with global studies indicates that till deposits are highly diverse, and their composition and properties are influenced by numerous factors, which makes global-scale comparisons of these sediments complicated. |
