Correlation of Lithuanian Maritime Pleistocene tills based on their mineralogy

Abstract

The previous studies of Pleistocene deposit in the Lithuanian Maritime Region (LMR) show the difficulty of its stratigraphical subdivision and correlation of sediment beds. Due to scarcity of biostratigrafical and absolute dating results, the variety of litostratigraphical criterions such as till petrography, geochemistry or even well rounded hornblende grain amount and other physical or visual characteristics used for litostratigraphy and correlation of tills did not give effective results. The article provides correlation of Pleistocene deposits based on mineralogical composition of the sandy fraction of tills from one geological profile located along the Lithuanian Baltic Sea coast using the multivariate statistics. The mineralogical data from six boreholes were statistically analysed and lithostratigraphical interpretation was made. Data analysis displayed that the till complexes have different amount of minerals from statistically derived mineral associations. It allowed distinguishing of six till complexes characterized by distinct mineralogical composition. These differences are clearly visible in the results of the statistical comparative analysis of the mineral composition of adjacent tills complexes. The stratigraphical identification of distinguished till complexes is based on its occurrence, inter-till deposit absolute dating and interglacial sediment palaeobotanical results.