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 region 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 into the cave entrance or redeposited in the cave by slope processes during the Last Glacial Stage. The layers of loess and loam overlie fluvial sands and gravels deposited during the Last Interglacial. Previous research at Kulna concentrated on the archaeology, palaeontology and dendrology of these entrance facies sediments. From these data, palaeoenvironmental conditions in the vicinity of the cave were reconstructed. Our results suggest that susceptibility variations and in particular variations in pedogenic susceptibility yield a more detailed record of the palaeoenvironmental conditions at the cave during the Last Glacial Stage. Magnetic susceptibility (X) was measured on approximately 700 samples collected throughout three well-studied profiles in the cave entrance. The x record is well defined and correlates from one profile to another. Mineral magnetic measurements [FD, ARM /SIRM, S-ratio, x(T)] suggest that x variations in the Kulna sediments from the Last Glacial Stage are controlled by the concentration of magnetite and/or maghemite formed during pedogenesis. After the removal of the effects of fine carbonate debris and detrital ferromagnetic minerals on the bulk x record, we obtained a record of pedogenic susceptibility (xp) that serves to quantify the concentration of magnetic minerals formed during pedogenesis. Therefore, xp can be thought of as a proxy reflecting the intensity of pedogenesis, which in turn is controlled by climate. Our xp record is also in good agreement with the median grain size record of the Kulna sediments (another proxy for climatic change). We suggest that in the case of Kulna, xp is more sensitive to climate change than bulk x. 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 suggest that Central European climate during the Last Glacial Stage was strongly controlled by the sea surface temperatures in the North Atlantic. Short-term warmer events and perhaps higher precipitation over the mid-continent increased the intensity of pedogenesis. Given the number of independent climate proxies determined from the entrance facies of the cave and their high resolution, Kulna is an extremely important site for studying Late Pleistocene climate

Preliminary study on the mineral magnetic properties of sediments from Kůlna Cave (Moravian Karst), Czech Republic

Magnetic property variations in marine, lacustrine and loess-paleosol sequences have proved to be useful proxies in climate change studies. However in order to correctly interpret the record of the magnetic property variations it is absolutely necessary to have a good understanding of the cause of the observed variations. Most of the ambiguity in loess-paleosol studies is in distinguishing the role of pedogenesis from other climatic factors. Studying the mineral magnetic properties of the protected cave sediments which have not undergone pedogenesis allows us to determine the degree to which detrital input is climatically driven. These results will help us better understand the variations observed in the surficial loess-paleosol sequences. This study reports mineral magnetic data collected from entrance facies sediments deposited during the early Wurmian glacial stage in the Kůlna Cave. The entrance facies sediments consist of loess-like silts with varying amount of talus. The magnetic susceptibility record from these sediments shows higher values in layers originating in colder climates which is different to that commonly observed in surficial loess deposits. Higher values of magnetic susceptibility in Kůlna sediments are probably due to higher concentrations of ferromagnetic minerals (magnetite and maghemite) and due to an increased proportion of superparamagnetic grains. The magnetic mineralogy and the grainsize distribution (grains larger than superparamagnetic) appear not to change throughout the studied profiles. Higher magnetic susceptibility accompanied by an increase in the superparamagnetic fraction observed in the sediments deposited during colder periods can be explained by an increased input from a pedogenic source when the vegetation cover was reduced and the erosion rate increased

New Chronological Evidence For The Middle To Upper Palaeolithic Transition In The Czech Republic And Slovakia: New Optically Stimulated Luminescence Dating Results

We report new optically stimulated luminescence (OSL) dates from the Central European sites of Kůlna, Stránská skála, Bohunice, Vedrovice V, Vedrovice Ia, Moravský Krumlov IV and Dzeravá skala, which date to the Middle-Upper Palaeolithic transitio

The Identification of Prehistoric Hunter-Gatherer Aggregation Sites: The Case of Altamira [and Comments and Reply]

It is a common assumption that an aggregation-and-dispersion pattern characterizes most of the world\u27s hunter-gatherers, both past and present. A clarification of the pattern is put forth in support of the view that there is more to it than factors of subsistence ecology. Because there are many variants of hunter-gatherer aggregations, in terms of both activities and the factors that promote and effect them, it is clear that there will also be variation in their duration, location, cyclicity, and extent and the number and kinds of personnel involved. The implications of this variability for archeologists are discussed, and the need for establishing specific archeological test implications for the identification of each variant of prehistoric aggregation sites is emphasized. Data from one hypothesized aggregation locale, the Early Magdalenian site of Altamira (Cantabria, Spain), are drawn upon for a better understanding of the kinds of analytical questions we must frame and the kinds of data and analysis we need in the attempt to identify aggregation sites. Specifically, the analysis of engraved Magdalenian bones and antlers is expected to add to extant interpretations of Magdalenian site utilization based on regional faunal and lithic data. Specific test implications are set forth for the view that the Altamira engraved bone-and-antler assemblage was generated by engraving activities different from but related to those of otherwise dispersed engravers or bearers of the portable engraved materials. It is shown that indeed the diversity of engravings at Altamira is statistically greater than at any of the other Early Magdalenian sites studied. Further, although aspects of the design system are present everywhere, there are certain features that are unique to the hypothesized aggregation site and insignificantly few other features that are found elsewhere if lacking at Altamira. The demonstrable diversity of the Altamira engraving repertoire is supportive of the hypothesis that otherwise dispersed engravers contrib