The Effect of Formation Processes on The Frequency of Palaeolithic Cave Sites in Semi-Arid Zones: Insights From Kazakhstan

Central Asian caves with Palaeolithic deposits are few but they provide a rich record of human fossils and cultural assemblages that has been used to model Late Pleistocene hominin dispersals. However, previous research has not yet systematically evaluated the formation processes that influence the frequency of Palaeolithic cave sites in the region. To address this deficiency, we combined field survey and micromorphological analyses in the piedmont zone of south Kazakhstan. Here we present our preliminary results focusing on selected sites of the Qaratau mountains. Sediment cover varies among the surveyed caves and loess-like sediments dominate the cave sequences. The preservation of cave deposits is influenced by reworking of cave sediments within the caves but also by the broader erosional processes that shape semi-arid landscapes. Ultimately, deposits of potentially Pleistocene age are scarce. Our study provides new data in the geoarchaeologically neglected region of Central Asia and demonstrates that micromorphology has great analytical potential even within the limitations of rigorous survey projects. We outline some of the processes that influence the formation and preservation of cave deposits inKazakhstan, as well as broader implications for the distribution of Palaeolithic cave sites in Central Asia and other semi-arid environments.

Submerged Speleothems and Sea Level Reconstructions: A Global Overview and New Results from the Mediterranean Sea

This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Favignana and Ustica islands (Sicily, Italy), are both characterized by continental, phreatic or marine layers. The U-Th and 14C ages of the new speleothems provide results of great interest for relative sea-level changes over the last 1000 years.

Increasing Pleistocene permafrost persistence and carbon cycle conundrums inferred from Canadian speleothems

Permafrost carbon represents a potentially powerful amplifier of climate change, but little is known about permafrost sensitivity and associated carbon cycling during past warm intervals. We reconstruct permafrost history in western Canada during Pleistocene interglacials from 130 uranium-thorium ages on 72 speleothems, cave deposits that only accumulate with deep ground thaw. We infer that permafrost thaw extended to the high Arctic during one or more periods between ~1.5 million and 0.5 million years ago but has been limited to the sub-Arctic since 400,000 years ago. Our Canadian speleothem growth history closely parallels an analogous reconstruction from Siberia, suggesting that this shift toward more stable permafrost across the Pleistocene may have been Arctic-wide. In contrast, interglacial greenhouse gas concentrations were relatively stable throughout the Pleistocene, suggesting that either permafrost thaw did not trigger substantial carbon release to the atmosphere or it was offset by carbon uptake elsewhere on glacial-interglacial time scales.

Namuliska jaskiniowe we współczesnym krajoznawstwie polskim – społeczna znajomość zagadnienia

Caves play an important role in tourist sightseeing. Some of them are eagerly visited by tourists due to the beautiful speleothems, the opportunity to see bats, the charm of underground passages and the aura of mystery. From the academic point of view, a particularly important element of caves is their deposits – the series of clastic sediments filling a cave cavity. They constitute an important source of information about the history and prehistory of human settlement in caves and their surroundings, and also the history of fauna and flora, the geological processes responsible for the accumulation of sediments and climate change. In this study, an evaluation of the importance of cave deposits to cave tourism is attempted, whether the Polish term „namulisko” (cave deposits) itself or the idea it expresses, is known in the public, and also how cave deposits are perceived by tourists, if at all, and which aspects are known. There was an attempt at recognition of this among tourists in the context of their general knowledge about caves. The research was carried out using anonymous questionnaires distributed among various social groups such as school and university students, teachers and tourists.

Last Interglacial (<i>sensu lato</i>, ~130 to 75 ka) sea level history from cave deposits: a global standardized database

Cave deposits are powerful archives for reconstructing past sea levels as they are generally protected from weathering and erosion by their location and can be dated with U-series methods. Two main categories of cave deposits are recognized as sea level indicators: phreatic overgrowth on speleothems (POS) and submerged vadose speleothems (SVS). POS have the great advantage that they precipitate on preexisting vadose supports at a brackish water level equivalent to sea level when air-filled chambers of coastal caves are flooded by rising sea. SVS are also useful, but sea level is inferred indirectly as periods of growth provide constraints on maximum sea level positions, whereas growth hiatuses, sometimes difficult to observe, may indicate times when cave passages are submerged by sea high stands, hence they record minimum sea level elevations. Here we describe a compilation that summarizes the current knowledge of MIS 5 (sensu lato) sea level captured by cave deposits. We used the framework of the World Atlas of Last Interglacial Shorelines (WALIS), a comprehensive sea level database, to provide a standardized format in order to facilitate scientific research on MIS 5 sea level. The discussion is MIS 5e-centered, but records that capture MIS 5c and 5a are also included. We present the data from 59 cave deposits (26 sea-level index points and 33 limiting points) in coastal caves located in eight different locations, and we include the spatial coverage, the samples used and their accuracy as indicators of sea level, the isotopic characteristics used to generate the U-Th chronologies, and their scientific relevance to understand past sea-level changes. The paper also emphasizes how some of these indicators are useful not only for the information they offer about the eustatic sea level, but more importantly: i) those from tectonically stable areas provide information on Earth deformation and regional ice sheet histories, thus refining the glacial isostatic adjustments models and ii) those from active regions can constrain regional tectonic uplift rates. The standardized sea-level database presented here is the first of its kind derived from cave deposits and contains all the information needed to assess former paleo relative sea level and the chronological constraints associated with them. The database is available open-access at http://doi.org/10.5281/zenodo.4313861 (Dumitru et al., 2020).