Chemical composition of cave sediment in Potočka zijalka, Mt. Olševa, North Slovenia

Abstract

Poto~ka zijalka was a station of Aurignatien hunters and the site of rich fossil remains of Pleistocene large mammals. Clastic sediments were deposited in Würm and are an intimate mixture of gravel, sand, silt and clay occurring in various proportions. The fractions form distinct populations, which were transported by different agents, like rockfall, flowing water, ephemeral torrent flows and cryoturbation. The sediment constituents are petrologically rather diverse and indicate that they were derived from different parent rocks -Mesozoic limestone, Permian-Carboniferous shales, Tertiary fine-grained sediments and fluvial pebbly deposits.Bulk chemical composition is strongly influenced by the limestone component, but the majority of trace elements, like Ti, Li, V, Fe, Co, Zn, Ga, Y, REE, Zr, Nb, Cs, Hf and Th originates from clay and fine silt, and Mn, Pb, Ni, Cu and Sn mainly from the heavz minerals in the sand fraction. Ca, Mg, Br, Rb, Sr and U show strong correlation with the amount of carbonate component. Rare earth elements, normalised to PAAS are not appreciable fractionated and show light positive europium anomalies. Kratka vsebinaPoto~ka zijalka je bila postaja aurignacienskih lovcev in je zato tudi bogato nahajali{~e fosilnih ostankov velikih pleistocenskih sesalcev. Klasti~ni sediment je nastal v würmu in predstavlja me{anico gru{~a, proda, peska, melja in gline v najrazli~nej{ih razmerjih. Frakcije vsebujejo populacije, ki so bile transportirane z razli~nimi dejavniki transporta kot so prosti pad, teko~a voda, ob~asni hudourni{ki tokovi in krioturbacija. Sediment sestoji iz drobcev, ki izvirajo iz razli~nih vrst kamnin -mezozojskih apnencev, permokarbonskih skrilavcev, terciarnih drobnozrnatih sedimentov in re~nih prodov.Na celotno kemi~no sestavo mo~no vpliva primes karbonatov. Ve~ina slednih prvin, kot so Ti, Li, V, Fe, Co, Zn, Ga, Y, prvine redkih zemelj, Zr, Nb, Cs, Hf in Th izvira iz gline in melja, Mn, Pb, Ni, Cu in Sn pa iz te'ke frakcije peskov. Ca, Mg, Ba, Rb, Sr in U so vezani na karbonatno sestavino sedimenta. Prvine redkih zemelj, normalizirane na PAAS, ne ka'ejo mo~ne frakcionacije, temve~ le manj{o pozitivno evropijevo anomalijo.