Reconstruction of palaeoflow and depositional dynamics from the Merjasec unroofed cave, Laze Plain (central Slovenia)

The Iberian Peninsula is a region of climatic and archaeological interest as it lies upon the boundary between the North Atlantic and Mediterranean climatic zones and was the last refuge of the Neanderthals. The influence of climate changes on Neanderthal populations remains a mystery due to the lack of independently-dated high-resolution terrestrial records of past climate and environmental change from the Iberian Peninsula. The primary aim of this project was to construct a palaeoclimate record using speleothems from Matienzo, northern Iberia, across the period encapsulating the Neanderthal demise. Contemporary cave monitoring of Cueva de las Perlas has demonstrated the potential for speleothems to be used as indicators of past climate and environmental conditions. Assessment of cave dynamics through a comprehensive monitoring programme has classified the karst hydrology, cave ventilation, processes influencing speleothem growth and proxies preserved within speleothem calcite. Three speleothems were used to develop records of past climate and environmental variability between 90,000 and 30,000 years ago. A long-term aridity trend was evident throughout the record which is interpreted as a response to orbital-forcing. Sub-orbital climate instability was superimposed onto this long-term trend as evidenced through wet-dry proxies (δ¹⁸O, δ¹³C, Mg and Sr). Millennial-scale events coincident with the timing of North Atlantic Heinrich Events have been identified and the sub-orbital climate variability resembles that of North Atlantic Dansgaard-Oeschger cycles. Therefore, evidence from the speleothems demonstrates a tight coupling of the North Atlantic Ocean-Atmosphere system throughout MIS3. The Cueva de las Perlas speleothems have established that the period of the Neanderthal demise was characterised by climate instability involving abrupt shifts and millennial-scale events, thereby adding climatic pressures at a time of anatomically modern human appearance.

Ground penetrating radar (GPR) using a special unshielded 50 MHz Rough Terrain Antenna (RTA) in combination with a shielded 250 MHz antenna was used to study the capability of this geophysical method for detecting cave sediments. Allochthonous cave sediments found in the study area of Lanski vrh (W Slovenia) are now exposed on the karst surface in the so-called “unroofed caves” due to a general lowering of the surface (denudation of carbonate rocks) and can provide valuable evidence of the karst development. In the first phase, GPR profiles were measured at three test locations, where cave sediments are clearly evident on the surface and appear with flowstone. It turned out that cave sediments are clearly visible on GPR radargrams as areas of strong signal attenuation. Based on this finding, GPR profiling was used in several other places where direct indicators of unroofed caves or other indicators for speleogenesis are not present due to strong surface reshaping. The influence of various field conditions, especially water content, on GPR measurements was also analysed by comparing radargrams measured in various field conditions. Further mineralogical-geochemical analyses were conducted to better understand the factors that influence the attenuation in the area of cave sediments. Samples of cave sediments and soils on carbonate rocks (rendzina) were taken for X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses to compare the mineral and geochemical compositions of both sediments. Results show that cave sediments contain higher amounts of clay minerals and iron/aluminium oxides/hydroxides which, in addition to the thickness of cave sediments, can play an important role in the depth of penetration. Differences in the mineral composition also lead to water retention in cave sediments even through dry periods which additionally contribute to increased attenuation with respect to surrounding soils. The GPR method has proven to be reliable for locating areas of cave sediments at the surface and to determine their spatial extent, which is very important in delineating the geometry of unroofed cave systems. GPR thus proved to be a very valuable method in supporting geological and geomorphological mapping for a more comprehensive recognition of unroofed cave systems. These are important for understanding karstification and speleogenetic processes that influenced the formation of former underground caves and can help us reconstruct the direction of former underground water flows.

Speleothems are recognised as valuable palaeo climate archives. This has lead to an increasing number of analysed speleothem proxy time series from caves that are distributed on a global scale. In particular speleothem δ18O and δ13C time series are investigated. A hotspot of analysed speleothem proxy time series is Europe, which makes it possible to perform spatio-temporal coherency analysis of speleothem proxy time series. For this aim a method is developed that is based on Principal Component Analysis (PCA). The method is based on a Monte Carlo approach and accounts for the speleothem age uncertainty and the different temporal resolution of speleothem proxy time series. This method is applied to compilations of European speleothem δ18O and δ13C time series. It is demonstrated that the results of the PCA for the compiled δ18O time series can be interpreted as a temperature proxy and as a precipitation/hydrology proxy for the compilation of δ13C time series. Furthermore, it is showed that the spatio-temporal coherence between the analysed speleothem δ18O and δ13C time series varied with time. Moreover, a change of the predominant pattern is observed at 4.0 ka. The second aim of this study is to analyse the change the observed speleothem δ18O gradient for European speleothems. A multi-box Rayleigh approach model is developed (Stable Isotope in Precipitation (SIP) model) that computes the stable isotope composition of precipitation, infiltrated water and calcite. The model is validated with measured precipitation δ18O and δD values from the GNIP dataset. It is demonstrated that the SIP model agrees with the observed δ18O and δD values for the analysed Central European and Northern European transect. Moreover, it is showed that the precipitation δ18O (δD) gradient depends on the North Atlantic Oscillation. This is interpreted as a change of the amount of moisture in the atmosphere for Central Europe. The application of the SIP model of palaeo climate speloethem δ18O gradients suggests that the climate was drier in the early- and mid-Holocene compared to present-day. In addition, the past δ18O gradients suggest a transition of the atmospheric circulation from a very negative NAO like pattern in the early-Holocene (11 ka) to a very positive NAO like pattern in mid-Holocene (4 ka) and that a reorganisation of the atmospheric circulation occurred at approximately 4 ka when present-day atmospheric circulation established.

Situated in North-west England, Ingleborough is near the centre of an area of 300 square kilometres of well-known karst topography (see Fig. 1). The limestone caves of the area are well known and were described in detail by Dr. M. M. Sweeting in the Geographical Journal of March 1950 (Sweeting, 1950). Over the last decade major improvements in caving equipment and standards have permitted much more detailed study and survey of the caves, particularly with regard to the geological features. In 1950, the information on the caves appeared to show that they occurred in a series of three well marked, narrow, horizontal zones, and Sweeting proposed that the caves were formed at a lowering series of water tables. However, recent evidence demonstrates that geological controls within the sub-horizontal limestones have been more important and the chronology of the caves only indicates a preglacial phreatic phase and a post-glacial vadose phase.x Throughout the world the environment for the formation of limestone caves has been ascribed to all three zones of karst groundwater (as defined by Cviji<5, 1918). An origin under vadose conditions, where the cave stream does not fill the passage but has an air surface above it, was postulated for the Yorkshire caves as early as 1907 by Dwerryhouse. Formation of caves at the water-table was argued by Swinnerton (1932), who suggested that maximum erosion should take place at the level where there was the greatest confluence of groundwater, and this theory was applied to the Yorkshire caves by Sweeting in 1950. The phreatic zone, at a greater depth where all cavities are filled with water and the flow is only under hydrostatic pressure, was claimed to be the environment of main cave development by Davis (1930) and Bretz (1942), but this theory has not previously been adopted for the caves of the Ingleborough region. The second of these theories?the water-table theory?is now complicated by the recent recognition of the fact that a water-table in the classical sense does not exist in cavernous limestones (Drew, 1966), such as the Carboniferous in the Ingleborough area. These basically non-porous limestones contain their groundwater in discrete channels, or caves, and there is no clear boundary between a zone of percolating groundwater, above a water-table, and a lower zone of water-filled cavities. Instead it is common to find dry caverns below surface rivers or other cave passages containing streams; the Gaping Gill cave is a good example for all three of its subsidiary entrance systems containing active streams, Stream Passage, Disappointment and Flood Entrance Pot-holes, are at some place vertically above the large dry passages of the lower, main, series. Any attempt at delimiting a conventional water-table in such an area results in a three dimensional surface so complex as to be valueless.z Detailed morphological studies of the cave passages in the Ingleborough district show that the various cave systems include examples of both phreatic and vadose origin.

Fluid inclusions in speleothem constitute a unique archive for palaeo-waters. This thesis deals with the investigation of fluid inclusions in speleothems and their possible use as a palaeotemperature archive. The main objective focuses on the calculation of noble gas temperatures, which can be derived from the temperature-dependent solubility of the noble gases He, Ne, Ar, Kr and Xe. An essential requirement is the determination of noble gas concentrations, which implies measuring the absolute gas amounts as well as determining the amounts of water released. Two ways of measuring the tiny water amounts (≤ 1 μl) extracted from the speleothems are presented and will be discussed with regard to the required precision. Furthermore, various techniques for the extraction of noble gases from the speleothems are investigated and analysed in terms of the intended application. It turned out that crushing under vacuum in a steel cylinder by milling with a magnetically movable steel ball is the most suitable technique. Additionally, the noble gas preparation and the mass spectrometric procedure, optimized for the measurement of tiny gas amounts, will be discussed. Finally, it is demonstrated that it is possible to determine reliable temperatures from fluid inclusions in speleothems and that the acquired results can be reproduced to a certain extent. From the stalagmite BU-U (Sauerland, NW Germany) six samples from one growth period were extracted and measured. Their results agree within the uncertainties although the samples are not totally identical. Measurements on other stalagmites (BU-1, BU-2) from the same cave revealed temperatures corresponding to the expected climatic conditions in the respective growth period. Typical uncertainties for these samples range from ≤ 1 ℃ to 2 ℃ at most. From the stalagmites BU-U and BU-1 a temperature record has been established by noble gas concentrations and will be discussed in combination with the stable isotope data. These exemplary applications reveal the high potential of the method presented.

In order to study paleoclimate and paleoenvironment in the southwestern Taiwan, we collected a stalagmite (DGS-01) which is 13.7cm in length from Jianfei Cave in Dagangshan Hill in 2009. The Pb-210 dating on the upper 0.6 cm of the stalagmite shows that the stalagmite stopped to grow at least 100 years ago. Three ICP-MS 230Th/U dates have been made on the stalagmite, but with large uncertainties due to high detrital Th contents. The two reasonable 230Th/U dates and Pb-210 dating indicate that the stalagmite had grown from 6000 years ago to about 100 years ago. The growing rates of the stalagmite are 0.040 mm/year in the upper 5.1 cm and 0.012 mm/year between 5.1 and 11.2 cm. The stalagmite DGS-01 exhibits clear growth laminations without apparent growth hiatus. In general, light δ18O and δ13C layers reflecting wetter climate are corresponding to lighter lamination bands, and vice versa. However, other non-climatic factors may affect the growth laminations too. Therefore, we should be cautious when we use the characteristics of stalagmite lamination to interpret climate change. From the trace elemental analyses, we calculate the mean Mg/Ca partitioning coefficient, DMg = 0.0255, and the mean Sr/Ca partitioning coefficient, DSr = 0.1216. Those parameters are the basic data for using the trace elements of the stalagmite DGS-01 to reconstruct paleoclimate. According to the δ18O and δ13C values of 140 samples from the upper 0-14mm of the staglagmite DGS-01, the climatic conditions during 100-450 years in the southwestern Taiwan can be separated into 3 stages. During the I stage (11.7-14mm in depth, from 450~390 years ago), the climatic conditions were dry under weaker summer monsoon, and C4/C3 plant ratio was increased in vegetation. During the II stage (4.8-11.6mm in depth, from 390 to 220 years age), the climatic conditions were relatively wet and stable under stronger summer monsoon. With more rainfall, the vegetation intensity was increased and the C3/C4 plant ratio might be increased. During the III stage (0-4.7mm in depth, 220 to 100 years ago), the averageδ18O and δ13C values were light representing wetter climate and more C3 vegetation. However, the variations of the δ18O and δ13C values were much larger than the previous stages, indicating climate change dramatically. The three stages were all in the Little Ice Age (LIA), reflecting that the climatic modes in the monsoon area had not only cold/dry and warm/wet patterns, but also cold/wet and warm/dry. The δ18O and δ13C records of stalagmite DGS-01 reveal 20-40 years periodical change, similar to the Bruckner cycle (35 years) and the 30-40 years period of the monsoon in the eastern Asia. Our preliminary study on the stalagmite provides the first Holocene record of high-resolution speleothem record in Taiwan. With future work on dating and complete comparative analysis, we are able to obtain climate and environmental changes in Taiwan during the past 6000 years.

Note: This edition of the SISAL database was withdrawn on 13 July 2020. It has been superseded by a new edition available at http://dx.doi.org/10.17864/1947.256. Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. Version 1b of the SISAL database contains oxygen and carbon isotope measurements from 440 individual and 15 composite speleothem records from 221 cave systems worldwide, as well as metadata describing their cave settings and age-depth models. New records have been added and some metadata has been amended. The SISAL working group has also created SISAL chronologies for 20 entities, all of which had no published chronologies. In order to assure traceability, any presentation, report, or publication that uses the SISALv1b database should cite Atsawawaranunt et al. (2018) (The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems; https://doi.org/10.5194/essd-10-1687-2018) and Comas-Bru et al. (2019) (Evaluating model outputs using integrated global speleothem records of climate change since the last glacial; https://doi.org/10.5194/cp-2019-25). If using individual sites or speleothems, the literature citations for published work provided in the database should also be cited. Contact information of data contributors of unpublished data is also provided and these should be contacted when unpublished records are used on an individual basis.

Speleogeneza je proces nastajanja, razvoja in izginjanja jam. Zaključni stadij razvoja jame imenujemo brezstropa jama. Proučevanje le-teh nam lahko pomaga pri razumevanju krasa in kraških pojavov. Ker so brezstrope jame ali kotanje na površju ali le zaplate nekraških sedimentov z bujnejšim rastjem, v članku preučujemo možnosti kabinetnega prepoznavanja teh pojavov na podlagi njihovih morfometričnih lastnosti in spektralnih lastnosti vegetacije, ki jih prerašča. Raziskava je osredotočena na širše območje Podgorskega krasa v jugozahodni Sloveniji.

Unroofed caves are old caves that were revealed on account of the lowering of the karst surface. They are preserved by their infill—mostly alluvium and flowstone. It became clear during the motorway construction undertaking in Slovenia that unroofed caves constitute a relatively common karst landform. In fact, more common than karstologists had imagined before the karst surface was uncovered through earthworks. The various types of notches occurring on the surface have long been interpreted as types of dolines or as the result of the lithological properties of rock and its fracturing. 75 km long and, on average, 25 m wide stretch of the motorway across the classical Karst gave up 350 caves, of which 90 are unroofed caves. Some of them make up the same cave system. New findings prompted karstologists to become more aware of these unique surface karst forms. In the process, numerous unroofed caves filled with all types of alluvium were discovered. There were several attempts at typification of the characteristic shapes of unroofed caves and to design partial models to explain their typical formation processes. The surface and subcutaneous dissolution of carbonate rock and its disintegration from back in the Ice Age, brought about the lowering of the karst surface. Old caves, which were formed by erstwhile water flows and are partly intersected by shafts which drain water from the permeable karst surface, pop up as either empty or filled with alluvium. The caves were formed as a part of a system of cavities in a period when impermeable rocks had enclosed the aquifer higher up, causing the underground water in the aquifer to be at a higher level. The hypothesis was that the karst topography and its remarkable systems of valleys can be traced back to former surface water throughflow. However, revealing the surface did not provide the evidence to support this hypothesis, instead obvious signs of former water throughflow in carbonate rock were identified—manifested as open and cut through old caves.

Reconstructing a Miocene pitfall trap: Recognition and interpretation of fossiliferous Cenozoic palaeokarst

Application of sedimentary and chronological analyses to refine the depositional context of a Late Pleistocene vertebrate deposit, Naracoorte, South Australia

Detailed knowledge of the past climate and environmental variability is vital in order to predict future scenarios with more confidence. High resolution and highly-resolved natural archives are therefore in growing demand (PAGES report, 2009). This thesis is part of a coordinated effort, STALCLIM project, where a series of state-of-theart methods in speleothems proxies were used in order to develop the full potential of speleothemsas paleoclimate and paleoenvironmental archive. The thesis investigates climate variations as recorded by speleothems from Schafsloch and Milandre caves, spanning time intervals of high scientific interest: 0 to 14 550 years BP and 130 000 to 230 000 years BP. The locations of the caves, Jura Mountains and the Alpstein Mountains (Swiss Alps) are regions highly sensitive to climate-induced changes in temperature, atmospheric pathways and/or environment evolution. In order to establish new climate records and resolve the paleoclimate questions, continuous geochemical analyses were applied, with high resolution stable isotopic and trace elements analysis and 230Th age measurements, and these were combined with thin section analysis of the calcite petrology. Where possible, we conducted continuous and temporal measurements in the caves where the samples were collected, to provide a better understanding of the cave environment. Chapters 2 and 3 highlight the sensitivity of high altitude speleothem proxies to small changes in temperature and water availability, both induced by internal and external climate drivers. The MF3 stalagmite, from Schafsloch Cave, provides a unique opportunity to investigate a regional expression of millennial-scale climate variability in Central Europe during MIS 6 and Late MIS 7. The sample records in high detail the structure of the penultimate deglaciation in the Alps, and brings new evidence regarding the nature of this important climatic transition. Chapters 4 and 5 show the high resolution composite δ18O record and elemental composition of speleothems from Milandre Cave, covering the Lateglacial- Holocene interval. A detailed comparison with Greenland ice cores and Gerzensee lake sediments (Central Switzerland) indicates similarities in the long timescale changes of atmospheric circulation patterns in the whole North Atlantic region after the last deglaciation. In contrast, during the Holocene, the signature pattern in the isotopic calcite δ18O data differs to that seen in Central Europe. This provides important insights into the regional teleconnections and local environmental reaction to changes in the temperature, seasonality of precipitation and atmospheric processes. The use of a robust δ18O/temperature transfer function has enabled a high resolution temperature reconstruction of the autumn to spring temperatures at the Milandre site for the last 14 550 y BP. In summary, this thesis provides new results on environmental and climatic variability in Switzerland during specific intervals over the last 230 000 years. It suports large teleconnections over the northern hemisphere and emphasizes the role of insolation and obliquity as important climate triggers in the region. These new high-resolution and precisely dated records of δ18O and cold season temperature reconstruction for the Jura Mountains over the last 14 550 y BP, are proposed as being representative for Central Europe.

Mass movements have been one of the most efficient processes controlling the morphogenesis of the Outer (Flysch) Carpathians. Dated by &lt;sup&gt;14&lt;/sup&gt;C method 180 landslides and related processes in the Polish Carpathians enabling to reconstruct mass movement chronology, confirm the thesis formulated by Starkel (1966), that the periods of acceleration of gravitational processes during the Late Glacial and the Holocene were connected with the stages of climatic humidity growths (Alexandrowicz, 1996; Margielewski, 2006; Starkel et al., 2013). Gravitational slope failures have often generated formation of non-karst caves. In the Polish part of the Outer Carpathians ca. 1400 caves, mainly of gravitational origin, have been explored up till now (Klassek, Mleczek, 2015). Part of these caves formed in the initial stage of landslide development, some ones formed during subsequent stages of landslide evolution (Margielewski, Urban, 2003; Lenart et al., 2013). Radiocarbon datings of speleothems allow us to reconstruct the stages of cave development and related mass movements. Pollen analysis of speleothems confirms these datings (Urban et al., 2015)

The largest unroofed cave in the entire motorway route across Classical Karst was the 230 m long unroofed cave named Brezstropa jama which was unearthed near the village of Povir. It contained flowstone, stalactites, stalagmites and various sediments. Inside the cave, flowstone has been preserved in the form of crusts, massive flowstone heaps, and free-standing stalagmites, but some broken off stalactites were also found. It is possible to reconstruct a part of the development of the Brezstropa jama unroofed cave based on the shape of the walls and the sediments. The cave is a remnant of a larger cave system which drained sinking stream waters from flysch. The preserved section of the passage was located deep beneath the surface. The cave had a through-flowing sinking stream, carrying large pebbles. The large share of flysch sandstone pebbles and their size allow the conclusion that ponors were not far off. There were no relevant barriers for the water flow on its course from the ponors to the cave. The formation of stalactites/stalagmites and flowstone heaps does not reflect external influences, although the growth of the stalactites and stalagmites was interrupted several times by stages of either erosion or sedimentation. One of these cave erosion stages also left its mark on the flowstone which is over 350 thousand years old. Next, the cave was filled with fluvial sediments. The infill prevented the further filling with flowstone, the collapse of the roof and the transformation of the walls by corrosion. Thus, the cave transformation came to an end, but not that of its surroundings. For the time being, we are still unable to date the precise age of the Brezstropa jama unroofed cave. The only indirect clue is the rate with which the surface is lowering. The age of the Brezstropa jama unroofed cave is defined by the time in which the water level of free-flowing rivers, such as the one flowing through the cave, dropped from 400 m to 180 m a.s.l. It took 750 thousand to 1.5 million years for the Brezstropa jama unroofed cave’s 50–100 metre-thick roof to be corroded down, while the cave itself or its infillings are probably even older.

Abstract. Ice caves exist in locations where annual average air temperature is higher than 0 °C. An example is Ningwu ice cave, Shanxi Province, the largest ice cave in China. In order to quantitatively investigate the mechanism of formation and preservation of the ice cave, we use the finite-element method to simulate the heat transfer process at this ice cave. There are two major control factors. First, there is the seasonal asymmetric heat transfer. Heat is transferred into the ice cave from outside very inefficiently by conduction in spring, summer and fall. In winter, thermal convection occurs that transfers heat very efficiently out of the ice cave, thus cooling it down. Secondly, ice–water phase change provides a heat barrier for heat transfer into the cave in summer. The calculation also helps to evaluate effects of global warming, tourists, colored lights, climatic conditions, etc. for sustainable development of the ice cave as a tourism resource. In some other ice caves in China, managers have installed airtight doors at these ice caves' entrances with the intention of "protecting" these caves, but this in fact prevents cooling in winter and these cave ices will entirely melt within tens of years.