Carbonate component prevails substantially over the silicate within the Quaternary detritial lacustrine sedimentary sequence sampled in the abandoned clay-pit in Srpenica, NW Slovenia. Sampling was done discriminately among dark and light laminae. Cluster analysis and other statistical methods of geochemical data interpretation from these samples show that dark gray laminae contain significantly more of the silicate componentand some heavy metals (Ni, Cu, Co, Zr) compared to light gray laminae. The differences in geochemical and mineral composition are the cause of lamination of this lacustrine sediment sequence. Moreover, the dark gray laminae are coarser - grained. Lamination is thus conditioned by changes in the in flow pattern of the detritial material from different source areas and not by seasonal sedimentary cycles.