A debris flow deposit in Mammoth Cave: field characterization

This work presents an analysis of a debris flow deposit below Earth’s surface in the Mammoth Cave System in Kentucky, USA, and is the first study to characterize an in-cave debris flow to this level of detail. The deposit, named Mt. Ararat by cavers, has a maximum thickness of 7 m, a head-to-tail length of 75 m, and a total volume of about 3400 m3, as determined by terrestrial LiDAR and electrical resistivity surveys. The deposit is chaotic, angular, matrix-supported, and roughly inversely graded, with grain sizes, quantified through various grain-size distribution measuring techniques, ranging from clay through boulders larger than 1 m. The clasts are predominantly Mississippian Big Clifty sandstone, which is allochthonous in this part of the cave. The angularity of the blocks in the deposit indicate that they had not experienced significant erosion; and therefore, are determined to have been transported only a relatively short distance over a short time. The deposit profile is compound in appearance with two heads. We thus interpret this as a debris flow deposit resulting from two distinct flow events, and present a chronology of events leading to the present-day Mt. Ararat in Mammoth Cave. The findings of this work will inform further studies of karst-related erosional events, sediment transport, and deposition at different scales in karst aquifers, as well as the ways in which surface and subsurface processes interact to contribute to karst landscape evolution.

Cave monitoring in Hungary: An overview

In this study, already published and new monitoring data are compiled from the Baradla and Béke caves in the Aggtelek Karst, from the Vacska Cave in the Pilis Mountains as well as from the Szemlőhegy and Pálvölgy caves in the Buda Hills. Recent investigations (2019–2020) include monitoring of climatological parameters (e.g., temperature, CO2) measured inside and outside the caves, and the chemical, trace element and stable isotopic compositions of drip waters. In the Baradla Cave, the main focus of the investigation was on the stable isotope composition and the temperature measurements of drip water. In the Vacska Cave, which belongs to the Ajándék-Ariadne cave system, CO2 measurements and drip water collection were conducted in order to perform chemical and stable isotope measurements. In the Szemlőhegy and Pálvölgy caves, the chemical and stable isotope compositions of drip waters at six sites were determined. These datasets were used to characterize the studied caves and the hydrological processes taking place in the karst, and to trace anthropogenic influences. Climatological investigation revealed seasonality in CO2 concentration related to outside temperature variation, indicating a variable ventilation regime in the caves. In addition, the contributions of the winter and summer precipitation to the drip water were also estimated, in order to evaluate the main infiltration period. The knowledge of these parameters plays a crucial role in constraining the carbonate precipitation within the cave. Thus, the dataset compiled in this study can provide a basis for the interpretation of speleothem-based proxies.

Evaluation of Adaptive Interaction Systems for Virtual Museum Development

Virtual Museum (VM) is an application of Virtual Reality (VR) technology generating realistic visualization and sensation to convince museum visitors to interact with digital content. There are many immersive VR devices that support interactive VM applications. We investigate appropriate devices for interaction within VM. We proposed a Storytelling platform to achieve device organization without modification, the story and interaction were self-adapted to the selected device. Three types of interactive content were designed on our Storytelling platform to be applied on different interaction systems: a 2D standard display, a 3D stereoscopic display and a full immersive CAVE. The results showed different performances of each system supporting VM developers to select an appropriate interaction system. The evaluation contributes to the design of content and interaction of VM development with more efficiency based on user requirements. HIGHLIGHTS Three types of interactive content were designed on our Storytelling platform to be applied on different interaction systems: A 2D standard display, a 3D stereoscopic display, and a full immersive CAVE The 2D Powerwall system with a wide range of views provides immersion. However, with two-dimensional displays, users lack depth perception Users spent more time in selection and manipulation in the 3D stereoscopic system because depth perception is added The CAVE system has user attraction or holding power, users spent more interacting time GRAPHICAL ABSTRACT

Nontuberculous Mycobacteria Prevalence in Aerosol and Spiders’ Webs in Karst Caves: Low Risk for Speleotherapy

A total of 152 aerosol and spider web samples were collected: 96 spider’s webs in karst areas in 4 European countries (Czech Republic, France, Italy, and Slovakia), specifically from the surface environment (n = 44), photic zones of caves (n = 26), and inside (aphotic zones) of caves (n = 26), 56 Particulate Matter (PM) samples from the Sloupsko-Sosuvsky Cave System (speleotherapy facility; n = 21) and from aerosol collected from the nearby city of Brno (n = 35) in the Czech Republic. Nontuberculous mycobacteria (NTM) were isolated from 13 (13.5%) spider’s webs: 5 isolates of saprophytic NTM (Mycobacterium gordonae, M. kumamotonense, M. terrae, and M. terrae complex) and 6 isolates of potentially pathogenic NTM (M. avium ssp. hominissuis, M. fortuitum, M. intracellulare, M. peregrinum and M. triplex). NTM were not isolated from PM collected from cave with the speleotherapy facility although mycobacterial DNA was detected in 8 (14.3%) samples. Temperature (8.2 °C, range 8.0–8.4 °C) and relative humidity (94.7%, range 93.6–96.6%) of air in this cave were relatively constant. The average PM2.5 and PM10 mass concentration was 5.49 µg m−3 and 11.1 µg m−3. Analysed anions (i.e., F−, Cl−, NO2−, SO42−, PO43− and NO3−) originating largely from the burning of wood and coal for residential heating in nearby villages in the surrounding area. The air in the caves with speleotherapy facilities should be monitored with respect to NTM, PM and anions to ensure a safe environment.

Undo Caves Multi-staged Karstic System and Temporary Camp of the Neanderthal Hunters

In Georgia, a strong foundation for scientific study of this period was developed in 1930-ies. Since then more than 500 Paleolithic sites were identified The frequency of paleolithic sites on the territory of Georgia was determined by geographic position of Georgia itself, as it is situated at the crossroads of Africa, Asia and Europe According to some archaeologists the archaeological evidence demonstrates the different local-cultural groups. Despite the small territory we have at least 5 local-cultural versions in the Middle Palaeolithic singled out with us four out of which are represented in the Rioni-Kvirila basin (Fig ). Most quantity of levallois industries were recovered in Imereti region (Western Georgia). 1. Drouchula,-Kudaro Local-cultural group.Mousterian assemblages characterized by blades and elongated points, as recovered in Drouchula, Tsona,Kudaro and other sites, resemble the “Tabun D-type” and Hummallian entities in the Levant.Unfortunatly, we have not the dates from this sites, but we assume that they are younger than Levantian “Tabun-D type”; at the same time, this industry has some similarities with the Northern-Caucasus Miqoqian industries , as well. 2. Tsutskhvati caves Local-cultural group. Multi-stage cave system characterized by the industry which resemble the Zagros region, but there are some differences-the non-Levalloias industry of Tsutskhvati is denticulated; 3. Tskaltsitela local-cultural group- Levalloiasian, denticulated industry (by M.Nioradze); 4. Tsopi Local-cultural.The industry of Tsopi site differs from above mentioned sites by the high quantity of the tools of Quina and Demi-Quina type; 5. Tskhinvali local-cultural group (according to v. Lubin)-Levalois, Unretouched industry. Another type of industry is represented I Ortvala Klde, Djieti open-air site etc.- Mousterian assemblages such as in Ortvala Klde demonstrates similarities with the Middle Paleolithic industries of Anatolia, the Zagros region-recurrent Levallois big number of the convergent tools. Most of the local-cultural groups and the sites are discovered in Western Georgia (Imereti Region) A first evidence of the Middle Paleolithic hunters temporary camp which, possibly has been used as place for some kind of rituals and where is represented a first evidence of the cave rock-art in Georgia has been determined in Rion-Kvirila basin as well. This is a cave-site named “Undo Cave”. Recently, we discovered some other cave-sites near Undo Cave. This fact gave a reason to consider Undo Cave as a one of the caves of Multi-staged cave system which doesn’t belong to any above mentioned groups.

Gravity as a tool to improve the hydrologic mass budget in karstic areas

Monitoring the water movements in karstic areas is a fundamental but challenging task due to the complexity of the drainage system and the difficulty in deploying a network of observations. Gravimetry offers a valid complement to classical hydrologic measurements in order to characterize such systems in which the recharge process causes temporarily accumulation of large water volumes in the voids of the epi-phreatic system. We show an innovative integration of gravimetric and hydrologic observations that constrains a hydrodynamic model of the Škocjan cave system (Slovenia). We demonstrate how the inclusion of gravity observations improves water mass budget estimates for the Škocjan area based on hydrological observations only. Finally, the detectability of water storage variations in other karstic contexts is discussed with respect to the noise performances of spring and super-conducting gravimeters.

Nyitni vagy nem nyitni? – Pilisi barlangok szellőzöttsége a geokémiai adatok tükrében

Speleothem formations are one of the most important and informative objects in paleoclimatological research. However, in order to interpret the data that reflect environmental conditions, we have to know the operation of the given cave, and it should be determined how the composition of the carbonate formed at the given site is related to the changes in the environmental parameters. The study presents the results of stable isotope geochemical analysis of speleothem formations and carbonate precipitated on glass plates collected in the Vacska Cave (Pilis Hills). The youngest layer of carbonate formations, formed in the last 1-2 decades, shows an isotope fractionation sign indicating strong ventilation, with the exception of a single site farthest from the entrance to the cave. The isotope shift was also accompanied by a change in carbonate fabric. Preceding the fabric change, the carbonate of the speleothem formations did not show ventilation-related shifts in the isotope compositions, suggesting that the exploration and opening of the cave areas may have caused the change. Based on this, we recommend the installation of local closures in the Vacska Cave and in the entire Ariadne cave system. The study provides a good example of how the results of basic research can be utilized in practical environmental protection, in the preservation of a strictly protected cave environment.

Biodiversity of the Huautla Cave System, Oaxaca, Mexico

Sistema Huautla is the deepest cave system in the Americas at 1560 m and the fifth longest in Mexico at 89,000 m, and it is a mostly vertical network of interconnected passages. The surface landscape is rugged, ranging from 3500 to 2500 masl, intersected by streams and deep gorges. There are numerous dolinas, from hundreds to tens of meters in width and depth. The weather is basically temperate subhumid with summer rains. The average yearly rainfall is approximately 2500 mm, with a monthly average of 35 mm for the driest times of the year and up to 500 mm for the wettest month. All these conditions play an important role for achieving the highest terrestrial troglobite diversity in Mexico, containing a total of 35 species, of which 27 are possible troglobites (16 described), including numerous arachnids, millipedes, springtails, silverfish, and a single described species of beetles. With those numbers, Sistema Huautla is one of the richest cave systems in the world.

The relative importance of wind-driven and chimney effect cave ventilation: Observations in Postojna Cave (Slovenia)

Density-driven chimney effect airflow is the most common form of cave ventilation, allowing gas exchange between the outside and the karst subsurface. However, cave ventilation can also be driven by other mechanisms, such as barometric changes or pressure differences induced by the outside winds. We discuss the mechanism and dynamics of wind-driven ventilation using observations in Postojna Cave, Slovenia. We show how seasonal airflow patterns driven by the chimney effect are substantially modified by outside winds. Wind flow over irregular topography forms near-surface air pressure variations and thus pressure differences between cave entrances at different locations. These pressure differences depend on wind speed and direction and their relationship to surface topography and the location of cave entrances. Winds can act in the same or opposite direction as the chimney effect and can either enhance, diminish or even reverse the direction of the density-driven airflows. To examine the possibility of wind-driven flow, we used a computational fluid dynamics model to calculate the wind pressure field over Postojna Cave and the pressure differences between selected points for different configurations of wind speed and direction. We compared these values with those obtained from airflow measurements in the cave and from simple theoretical considerations. Despite the simplicity of the approach and the complexity of the cave system, the comparisons showed satisfactory agreement. This allowed a more general assessment of the relative importance of wind pressure for subsurface ventilation. We are certain that this example is not unique and that the wind-driven effect needs to be considered elsewhere to provide better insights into the dynamics of cave climate, air composition or dripwater geochemistry.

The Coume Ouarnède System, a Hotspot of Subterranean Biodiversity in Pyrenees (France)

Located in Northern Pyrenees, in the Arbas massif, France, the system of the Coume Ouarnède, also known as Réseau Félix Trombe—Henne Morte, is the longest and the most complex cave system of France. The system, developed in massive Mesozoic limestone, has two distinct resurgences. Despite relatively limited sampling, its subterranean fauna is rich, composed of a number of local endemics, terrestrial as well as aquatic, including two remarkable relictual species, Arbasus caecus (Simon, 1911) and Tritomurus falcifer Cassagnau, 1958. With 38 stygobiotic and troglobiotic species recorded so far, the Coume Ouarnède system is the second richest subterranean hotspot in France and the first one in Pyrenees. This species richness is, however, expected to increase because several taxonomic groups, like Ostracoda, as well as important subterranean habitats, like MSS (“Milieu Souterrain Superficiel”), have not been considered so far in inventories. Similar levels of subterranean biodiversity are expected to occur in less-sampled karsts of central and western Pyrenees.