A Late Pleistocene palaeoclimate record based on mineral magnetic properties of the entrance facies sediments of Kulna Cave, Czech Republic

Kulna Cave is located in the Moravian Karst, a well-developed karstic regio n formed in Devonian limestones in the eastern part of the Czech Republic. The entrance facies sediments in the cave consist of interbedded layers of silts (loess) and clay-rich silts (loam) that were either directly blown in to the cave entrance or redeposited in the cave by slope processes during t he Last Glacial Stage. The layers of loess and loam overlie fluvial sands a nd gravels deposited during the Last Interglacial. Previous research at Kul na concentrated on the archaeology, palaeontology and dendrology of these e ntrance facies sediments. From these data, palaeoenvironmental conditions i n the vicinity of the cave were reconstructed. Our results suggest that sus ceptibility variations and in particular variations in pedogenic susceptibi lity yield a more detailed record of the palaeoenvironmental conditions at the cave during the Last Glacial Stage. Magnetic susceptibility (chi) was measured on approximately 700 samples col lected throughout three well-studied profiles in the cave entrance. The chi record is well defined and correlates from one profile to another. Mineral magnetic measurements [F-D, ARM/SIRM, S-ratio, chi (T)] suggest that chi v ariations in the Kulna sediments from the Last Glacial Stage are controlled by the concentration of magnetite and/or maghemite formed during pedogenes is. After the removal of the effects of fine carbonate debris and detrital ferromagnetic minerals on the bulk chi record, we obtained a record of pedo genic susceptibility (chi (p)) that serves to quantify the concentration of magnetic minerals formed during pedogenesis. Therefore, chi (p) can be tho ught of as a proxy reflecting the intensity of pedogenesis, which in turn i s controlled by climate. Our chi (p) record is also in good agreement with the median grain size record of the Kulna sediments (another proxy for clim atic change). We suggest that in the case of Kulna, chi (p) is more sensiti ve to climate change than bulk chi. The Kulna pedogenic susceptibility record shows variations on both long and short timescales. The long-term trends are in good agreement with the deep -sea SPECMAP record, while the short-term oscillations correlate well with rapid changes in the North Atlantic sea surface temperatures. Our results s uggest that Central European climate during the Last Glacial Stage was stro ngly controlled by the sea surface temperatures in the North Atlantic. Shor t-term warmer events and perhaps higher precipitation over the raid-contine nt increased the intensity of pedogenesis. Given the number of independent climate proxies determined from the entrance facies of the cave and their h igh resolution, Kulna is an extremely important site for studying Late Plei stocene climate.