We synthesize information on results and age of cave sediments from Slovenia. The studied sites were mostly from the Classical Karst which is situated in the NW part of Dinarides and some from the ...Slovenian Southern Alps. Protected in caves, sediments are generally well preserved and reveal an exceptionally good, multi-proxy record of surface environmental conditions at the time of their deposition. Here we describe results of the systematic acquisition of palaeomagnetic data within individual segments of studied sediment sections with special focus on relict and unroofed caves. In intervals with polarity change, the frequency of sampling was so high that almost continuous records of rockmagnetic and palaeomagnetic parameters were obtained. The construction of high-resolution magnetostratigraphic profile supported magnetostratigraphy correlations among profiles. Palaeomagnetic and magnetostratigraphy results were calibrated by relative, numerical, calibrated and correlated dating methods, where possible. Age sequences were compiled from spatially and temporally highly discontinuous sediment records covering different ages within the Cenozoic era. The robust chronology was constructed. Calibrated data contributed to the interpretation of speleogenesis, deposition mechanism in caves, and indirectly to the time of karst evolution and the succession of tectonic phases and climate changes. The research indicated that most of sediments in relict and unroofed caves are up to 5 Ma old which contrasts to the traditional concept of Pleistocene age of cave sediments and that caves themselves are not much older. Cave sediments have proven to be an important source of information on depositional style in caves which indirectly reflected the evolution of the surrounding landscape especially the evolution of catchment areas – i.e. climatic changes with flood events or/and changes of the tectonic regimes during Cenozoic.
A flowstone section in the Račiška pečina Cave (Classical Karst, SW Slovenia) records multiple chronostratigraphic and palaeoclimatic proxies that can be correlated with other records on the global ...scale (Mediterranean region, Japan). Its upper part has an excellent record of the Matuyama/Brunhes (M/B) magnetic reversal. The M/B reversal zone, which is 6 mm in thickness, was detected by a high-resolution palaeomagnetic analysis of the sequence. An age model based on oxygen isotopic stratigraphy locates this quick transition in mid-MIS 19, between 777.9 and 777.2 ka, with the midpoint at 777.7 ka. The transition is marked by abrupt changes in stable isotopic compositions, trace element concentrations and flowstone fabrics that point to temperature and precipitation changes. Two distinct maxima in trace element concentrations at the beginning and the end of the M/B transition indicate two periods of higher precipitation, with increased washes of clay minerals into the cave. In addition, the stable isotopic (δ13C and δ18O) compositions indicate that significant cooling and high precipitation occurred during the M/B reversal within the generally warm MIS 19.
In this article, we present issues arising from Terrestrial Laser Scanning of large natural caves using the example of Škocjan Caves, a UNESCO World Heritage Site. Regarding pre-existing tachymetric ...survey of the passages and volumes calculated from them, the scanning of such a large cave was an even bigger challenge for the team. The cave of almost 6 km long passages with dimensions approx. 30 m x 40 m and max. heights up to 145 m, was scanned from 370 stations. Process of surveying the cave, involves establishing scanner positions through the cave, where scans will overlap, in a progressive route and once back on the surface, collecting, cleaning and stitching the scans into a point cloud 3D model. A total of 8.3 billion points were captured and 2,600 high-resolution photos taken. With Reigl’s RiSCAN Pro software, a point cloud model was registered and then exported to Hexagon’s 3D Reshaper to create a full surface model from which all measurements and calculations were made. Additionally, data acquisition using a camera on an unmanned airborne vehicle was used. By photogrammetric approach, digital terrain model of a surface was built and then tied to the cave model within 3D Reshaper. The resulting high resolution - point cloud model may be used for various purposes such as: volume calculations, detection of geological and speleogenetical features, etc. With a volume of 2.55 million cubic metres, Martel’s Chamber is confirmed to be the 11th largest cave chamber in the world at the moment.
The retreat of ice shelves and glaciers over the last century provides unequivocal evidence of recent global warming. Glacierets (miniature glaciers) and ice patches are important components of the ...cryosphere that highlight the global retreat of glaciers, but knowledge of their behaviour prior to the Little Ice Age is lacking. Here, we report the uranium–thorium age of subglacial carbonate deposits from a recently exposed surface previously occupied by the disappearing Triglav Glacier (southeastern European Alps) that may elucidate the glacier's presence throughout the entire Holocene. The ages suggest the deposits' possible preservation since the Last Glacial Maximum and Younger Dryas. These thin deposits, formed by regelation, are easily eroded if exposed during previous Holocene climatic optima. The age data indicate the glacier's present unprecedented level of retreat since the Last Glacial Maximum and the potential of subglacial carbonates as additional proxies to highlight the extraordinary nature of the current global climatic changes.
Slavinski ravnik je manjše korozijsko uravnano območje Dinarskega krasa v Sloveniji in leži na stiku med neprepustnimi flišnimi in zakraselimi karbonatnimi kamninami, kjer so se oblikovale najbolj ...reprezentativne ponorno kontaktne kraške oblike. Zaradi erozije, večfaznega regionalnega tektonskega zvišanja območja in sedimentacije so se oblikovali paragenetski jamski sistem ter aktivne in reliktne slepe doline, ki kažejo morfogenetske stopnje raziskovanega območja. Za boljši pregled in podrobnejše razumevanje preteklega in sedanjega dogajanja na dinamičnem kraškem sistemu, v katerem je hidrologija tesno povezana s prostorsko razporeditvijo in obsegom kontaktnih kraških (alogenih) morfoloških značilnosti, smo izvedli geomorfološko in sedimentološko kartiranje. Zemljevidi so bili digitalizirani z uporabo ESRI ArcMap in Golden Software Surfer na podlagi DEM in posnetkov LiDAR. Pri raziskovanju smo proučevali aktivni jamski sistem Markov spodmol in Vodna jama v Lozi, reliktno jamo Brezstropa jama v Lozi, slepo dolino Biščevci, slepo dolino Sajevško polje, slepo dolino Ivačevci ter akumulacijo sedimentov na Sajevškem polju ter določali aktivne in reliktne (zakrasele) morfološke elemente. Njihova lega, medsebojna povezanost in pojavnost nakazujejo na različne stopnje oblikovanja severnega roba Slavinskega ravnika v vsaj zadnjih štirih milijonih let. Gre za edinstveno celovito študijsko območje, kjer lahko opazujemo izpostavljene in ohranjene elemente stopnjevanja v razvoju ponorno-kontaktnega krasa, ki je v večini primerov slabo ohranjen zaradi erozijskih in kraških denudacijskih procesov.
The sedimentological record in the Račiška pečina cave sediment sequence is one of the best-preserved cave records of palaeoenvironmental changes for the last 3.4 Ma. However, as it is typical for ...cave terrestrial records, it contains many hiatuses in sedimentation. The section study helped to change the state of knowledge and understanding of the long-lasting deposition characteristics in the caves and provided enormous data on environmental changes over time. In the sequence are by magnetostratigraphy well recorded Pliocene/Pleistocene transition at 2.59 Ma, the Matuyama/Brunhes boundary at 0.773 Ma, and the presence of Olduvai subchron between 1.78 and 1.925 Ma. Records of small mammals from the lower part of the section (a molar of Apodemus cf. atavus and dental fragments of Borsodia sp., and Pliomys sp.) suggest MN17 age, Clethrionomys cf. glareolus from the upper part suggests the Late Early or Middle Pleistocene age. Also worth mentioning are records of snail shells Aegopinella sp. and a troglobiont snail Zospeum sp. In the upper part of the section Ursus ex gr. spelaeus was confirmed in the yellow clay layer older than ~72 ka, and soot material at the top of the section was radiocarbon dated on ~11 ka, ~9 ka, and ~3 ka. A detailed chronology of the Račiška pečina section based on magnetostratigraphy and isotopic oxygen stratigraphy was created and correlated with palaeontological, U-series, and radiocarbon results. Before the hiatus 2.6-2.5 Ma ago, the oxygen record was mainly shaped by regional Mediterranean Sea factors. After this boundary, the RP record becomes more similar to the LR04 stack, implying the increased influence of Atlantic Ocean factors.
Palygorskite is fibrous mineral representing the transitional phase between chain silicates and layer silicates with modulated phyllosilicate structure. Although often found in carbonate ...environments, it forms quite uncommon constituent of cave fills. Palygorskite occurs in cave fills in two forms: (1) allogenic palygorskite which in arid and semiarid conditions can represents substantial constituent of cave fills, often associated with smectite, gypsum, calcite and halite; it is airborne or transported by surface run-off to caves from desert soils and paleosoils, calcretes, dolocretes and related deposits in cave surroundings. (2) Authigenic palygorskite occurs as in situ precipitate in cave fills from percolating water solutions and/or transformation of smectite and kaolinite in dry evaporative conditions and suitable geochemical composition of solutions. In carbonate hostrocks palygorskite fills fissures and faults and often it is found in cave walls. It occurs commonly as part of the "mountain leather" as a result of hydrothermal and/or weathering processes or represents a product of in situ chemical precipitation from percolating meteoric solutions with suitable pH a redox conditions and chemical composition.
So far, the longest known unroofed cave in Slovenia has been found on the Slavinski ravnik, southwest of Postojna. From its position on the surface, its shape, and its containing sediments, we can ...infer its spatial and temporal development, as well as the processes and evolution of the contact karst in its hinterland. The corrosional plain Slavinski ravnik is a small area of the Dinaric Karst in Slovenia, located at the contact between impermeable flysch and karstified carbonate rocks, where many contact karst features formed. Due to erosion, multi-phase regional tectonic uplift, and sedimentation, a paragenetic cave system, active and relict blind valleys have formed. During the geomorphological mapping, elements were examined and drawn using ESRI ArcMap and Golden Software Surfer, and the stages of their formation were observed. During the survey, the active cave system Markov spodmol and Vodna jama v Lozi, the relict unroofed cave Brezstropa jama v Lozi, Biščevci blind valley, Sajevško polje blind valley, Ivačevci blind valley, and Sajevško polje sediment accumulation were studied. The changing hydrological regime, the allogenic sediments, the distribution of active and relict ponors, and the placement of active and relict elements of these contact karst forms, show different stages of formation and subsequent development of the northern border of Slavinski ravnik. The geomorphological map of these contact karst features and their following studies give us an insight into the morphogenesis of the southern karst periphery of the Postojna Basin as an exceptional - relatively small but highly variable Slovenian contact karst site.
Kahf Kharrat Najem Cave is a small cave in United Arab Emirates (UAE) that hosts a bat colony which is the source of guano deposits and peculiar centimeter-long yellowish stalactites. The mineralogy ...and geochemistry of these deposits were analyzed using powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopic microanalysis (EDX), scanning electron microscope (SEM), and stable isotope composition (δ 13 C and δ 15 N). Urea CO(NH 2) 2 was found to be the main compound of these stalactites, while allantoin C 4 H 6 N 4 O 3 was found to be an accessory urea byproduct. This paper is the first to mention allantoin in a cave environment. We also identified rare sulfate minerals (aphthitalite, alunite) and phosphates that probably correspond to the archerite-biphosphammite series. The occurrence of these rare bat-related minerals is due to the extremely dry conditions in the cave, which accounts for the extraordinary preservation of the guano deposits and allows for the crystallization of these very soluble minerals. cave minerals, allantoin, bat guano, bat urea, Kahf Kharrat Najem Cave, United Arab Emirates
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