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2D electrical resistivity tomography (ERT) data inversion and ground penetrating radar (GPR) techniques were used to investigate a cave in New Netim area, southeastern Nigeria. The aim of the research was to apply the non-destructive geophysical techniques in delineating a cave in New Netim. The Wenner electrode configuration was used during the electrical resistivity tomography data acquisition while the common-offset mode was used in the ground penetrating radar scanning. The ERT inversion and GPR results quantitatively show strong contrast in electrical resistivity and dielectric permittivity between the host rock (i.e., limestone) and the void. The differences in the electrical properties and dielectric permittivities of the top loamy soils, weathered limestone and the host rock (i.e., Mfamosing limestone) observed, in contrast to the response from the void were explored. The two combined geophysical techniques with their inversion results gave a reliable near surface geologic model, where both methods show relatively good correlation with regards to delineating the depth to top of the cave (~2.7 m). The joint interpretation of the ERT and GPR was effective in reducing the uncertainty associated with geophysical methods used in locating cavities on a standalone basis. The low cost, fast, environmental friendly and high resolving abilities though at shallow depths of the ERT and GPR techniques have continued to favour their usage in resolving near surface environmental and engineering problems. Generally, caves provide important geotourism attraction sites, hence certain recommendations were put forward that can guide further studies, like the application of Steiner’s geostatistical inversion techniques and other post-exploration development strategies.

Recently, several studies have presented quantitative data of lithic assemblages from Islands Southeast Asia (ISEA), based on technological and morphological analyses. While this has led to a better overall understanding of the nature of these assemblages, there is still lack of clarity about the relationship between manufacturing technology and usage. Accordingly, this study collected detailed data of lithic assemblages from Callao Cave in northern Luzon, Philippines. Multifaceted analyses including technological and morphological analysis and use-wear analysis were conducted to clarify the actual nature of lithic technology and tool use in relation to human behavior. Results of the technological and morphological analysis show that several core tools share same types of secondary reduction (retouch) with flake tools, while there are several retouched tools (flake tools and core tools) with several types of secondary reduction (retouch). In addition, there are no major differences between the sizes of the core tools and flake tools. Result of the use-wear analysis indicates that several retouched areas on both the core tools and flake tools were actually used. These stone-tool manufacturing and usage characteristics suggest that the hunter-gatherers who left the assemblages did not clearly distinguish between cores and flakes (or between core tools and flake tools), and did not treat lithic tools as single-function items. That is, it appears that secondary reduction was completed depending on the shapes, thicknesses, and angles of the edges of these lithic artifacts. The users/manufacturers thus placed emphasis on functional edges. It also seems that the core tools were used as both tools and objects for flake production. The characteristics of the assemblages in manufacturing and their usage suggest that lithic artifacts and lithic raw materials were used in Callao Cave efficiently and economically. Furthermore, in terms of their primary and secondary reduction processes, the assemblages from Callao Cave are considerably different from Upper Paleolithic assemblages found in the northern regions of Eurasia. This indicates that the characteristics of stone tool manufacturing and usage in Callao Cave reflect another strategy of early modern humans for using lithic raw material. However, these characteristics of the assemblages may most closely reflect the characteristics of the occupations and activities in the site. Accordingly, similar analyses, including technological and morphological analysis and use-wear analysis, need to be conducted on other lithic assemblages which are composed of many lithic artifacts in ISEA.

Caves are rare in northeast Africa and, thus, deserve attention as potential geoheritage objects (geosites). Assessment of Djara Cave and its vicinity (Western Desert, Egypt) has permitted to document unique features, such as the cave itself as a peculiar subsurface landform, speleothems providing data for palaeoenvironmental reconstructions, rock art demonstrating elements of past landscapes, siliceous nodules weathered from Eocene limestones and a network of dry drainage channels indicative of wetter palaeoenvironments. These features are assigned to geomorphological, sedimentological and palaeogeographical types of geoheritage. Djara Cave and its vicinity are proposed as a geosite of national rank; it is vulnerable to anthropogenic stress and needs geoconservation measures and instalment of interpretative signs. This geosite is already popular among tourists, and can be used for further tourism development. More generally, the presence of caves in Egyptian desert areas makes possible the recognition of national speleological heritage that requires special country-level strategies of management.

The Kospi Spi Cave is situated in the well-karstified Qamchuqa limestone of the Cretaceous age. This study encompasses the facts on the medium sized cave. The entrance of the cave is located at 1,400 meters above sea level, the highest amongst the adjacent discovered caves. Its total sightseen extent is around 200 meters. The cave is a remnant gulp hole expanded by a sinking stream throughout the Late Neogene Time.

Shanidar Cave is located in north Iraq (Kurdistan Region), it is one of the most well-known caves in the region due to its archeological significance. It is an archaeological site which is located within Bradost Mountain north of Erbil city. In the cave, eleven skeletons of Neanderthals, have been found dating back to 65000 – 35000 years B.C., they were called Shanidar (1-11). The cave also contains two later proto-Neolithiccemeteries. The cave is developed due to dissolution of limestone beds of the Qamchuqa Formation which forms the carapace of Bradost Mountain (anticline). Currently, the cave and the downslopes to the foothills of the mountain are limited by a fence. The cave can be reached by a paved road to the foothills level, then by stepping following artificially constructed leader which is designed and constructed by local materials from stones and wood giving to the leader a natural view. The Shanidar cave is highly recommended to be a national Geopark due to its archeological significance

The study focused on two important sites containing many caves sites located in the west of Al Anbar Governorate. The first site is Um El-Githoaa cavity in Hit region, a cave or trunks was chosen to show the aesthetic of this cave in terms of its shape and dimensions. The maximum diameter is 22.1m, while the perpendicular diameter is 18.5m. It is a dome shape and the height of its roof reaches about 2m located in the stratigraphic sequence falls within the massive gypsum, Fatha Formation (Middle Miocene). Geoelectrical exploration was chosen on the southern side of the cave to check whether the sinkholes scattered in the area are connected to subsurface caves or not. Using a Dipole-dipole array was chosen along a traverse, shown there are three sub-surface caves. This indicates that these phenomena are widespread in the region. The second location is Haditha, Barwana Village which was chosen to study where the cave is located in unconformity breccia zone between Anah Formation (Upper Oligocene- Lower Miocene) and Euphrates Formation (Lower Miocene- Middle Miocene). Barwana cave extends to the north 30 m and then tends to the west extend about 1 km within fragile breccia layer with incoherent components and ends with a small opening at the Euphrates River. This phenomenon was not present in the hard gypsum rocks in the Hit region, it was observed to have a large oval shape

The efficiency of archaeological studies inside caves could be greatly enhanced by geophysical methods because of their potential for examining deposit structure and features. Application of those methods in caves entails a number of problems caused by limited space for measurements and the complexity of the surrounding medium s structure as compared to above-ground measurements. In 2017, Selungur Cave in the Fergana Valley, Kyrgyzstan, was examined using electrical resistivity tomography. Because of the above concerns, in the course of the work the question of the reliability of the results arose. To clarify the issue, a numerical experiment was performed to assess the effect of the three-dimensional cave geometry on the results of a two-dimensional inversion. It was found that variations of cave geometry parameters result in unexpected false anomalies, and considerable errors in bedrock location and resistivity can occur. In the case of downward diverging cave walls, an accurate resistivity section can be obtained by using the inversion based on a two-dimensional model. Therefore, electrical resistivity tomography in caves with similar geometry can yield reliable results concerning the shape of bedrock surface, the thickness of sedimentary layers, and size and position of inclusions such as fallen fragments of roof therein.

Visibility has been the subject of study in Palaeolithic rock art research ever since the discovery of Altamira Cave in 1879. Nevertheless, until now, the different approaches have been based on subjective assessments, due to computational limitations for a more objective methodology. Nowadays, cutting-edge technologies such as GIS allow us to address spatial studies in caves and overcome their geomorphologically complex and closed characteristics. Here we describe an innovative methodology that uses computing tools available to any researcher to study the viewsheds of the graphic units in decorated caves. We have tested its validity on the recently discovered rock art ensemble of Atxurra Cave, in Northern Spain. We demonstrate that this technology (GIS), widely used in other fields of archaeology, especially in outdoor studies, is also useable in caverns, taking into account the complex morphologies -ceilings and diverse floor-levels, for example. These programmes have also allowed us to consider the lighting systems used by the prehistoric groups inside the cave, as well as various data previously estimated by other authors, such as the height of individuals during the European LUP. The dynamism of these tools −2.5D-, as well as the advancement of new 3D GIS technologies, will allow in the future remarkable progress in these types of structural studies for a better understanding of Palaeolithic cave art phenomena.

Švédův Stůl Cave in the Moravian Karst has been excavated several times since Martin Kříž started the first excavation in 1886. Two parts of the site were re-excavated in 2019. The primary aim was to conduct classical as well as innovative and experimental sedimentological and geoarchaeological investigations of sediments from the discarded spoil heap outside the cave entrance (trench C–D). Intact sediments with a small number of lithic artefacts and a large number of animal bones were also excavated during the 2019 excavation (trench A–B) located under the trench excavated by Bohuslav Klíma’s team in the 1950s. An attempt is being made using pXRF, benchtop ED-XRF and ITRAX techniques to link some of the sedimentary material in the spoil heap (C–D) with the stratified sediments in trench A–B. Animal bones and lithic artefacts were found in both trenches. Numerous samples were collected for geoarchaeological, palaeoenvironmental and dating analyses and the results will be published in upcoming publications.

Stylistically unique black rock drawings have been discovered in Andriamamelo Cave in western Madagascar. Several image groupings comprise naturalistic scenes with anthropomorphic, zoomorphic, and ...

Water seepage is the primary cause of stone carvings corrosion in karst caverns, which is typically treated with cement-based grout intervention. In this paper, long-term monitoring (more than 1 1/2 years) was carried out in Qinglin cave and Yanxia cave in Hangzhou, China, to quantitatively evaluate the advantages and disadvantages of ordinary Portland cement- and superfine cement-based grout intervention. Results showed that both materials were efficient in preventing water seepage, reducing it by half after the grout interventions. Grout intervention had obvious efficacy in blocking off the strong water seepage points, at the same time decreasing seepage differences among seepage points. Ion Chromatography results suggested that the concentrations of Ca2+, Cl− and SO42− in the seeped water in both caves increased after intervention, and the concentration of SO42− in the seeped water after superfine cement application in Qinglin cave was much more than that in the seeped water in Yanxia cave, where ordinary Portland cement was applied. Therefore, using superfine cement may bring more potential risks than ordinary Portland cement. However, X-ray diffraction (XRD) and conductivity analysis results presented that these ions seemly did not deposit on rock surfaces of the caves during the monitoring period.

Um El-Adam cavity is one of the well-known cavities inside gypsum rocks in the Hit region, western Iraq, where this was chosen as a case study to evaluate 3D resistivity imaging technique detection and imaging of this type of cavity in complicated lithology. 3D view fulfilled by collating four 2D resistivity-imaging lines. The 2D resistivity imaging survey was carried out by Dipole-Dipole array with (n) factor and electrode spacing (a) of 6 and 2m, respectively. Both conventional inversion methods obtained the 2D and 3D models: standard least-squares and robust constrain options. The two options were able to define clearly the cave, but the second was more accurate, the dimensions of the cave in the inverse model closer to the actual dimensions. Horizontal slices displayed the final 3D model to reveal a 3D resistivity distribution with depth. The effect of Um El-Adam cavity appears after 1.5 m on the model slices, which is represented by increasing resistivity contrast compared to surrounding sediments. At the seventh and eighth slices, it was found that the size of the cavity exceeded compared with the actual dimensions. The results of this study indicated the high potential of this method for the detection and delineation of subterranean caves.

Speleotourism implies visiting caves and respecting geomorphological values. A visit to the caves must include certain rules of conduct and implementation of geoethical values to achieve sustainable speleotourism development. This paper investigates the tourist traffic of an authentic cave in northwestern Bulgaria, the Magura Cave, which is a speleological object with exceptional potential for the development of speleotourism. The explored cave includes unique examples of cave paintings and imposing historical values. The research methodology mainly included descriptive analysis of data obtained by the administrative staff of the Municipality of Belogradchik. The data of tourist visits are presented in tables and graphs. The research results indicate the current state and potential prospects for the development of speleotourism in the Magura Cave. Moreover, the paper presents measures for more effective development of speleotourism, which are of special importance for organizational and cave management structures.

With the depletion of easily minable coal seams, less favorable reserves under adverse conditions have to be mined out to meet the market demand. Due to some historical reasons, large amount of remnant coal was left unrecovered. One such case history occurred with the remnant rectangular stripe coal pillars using partial extraction method at Guandi Mine, Shanxi Province, China. The challenge that the coal mine was facing was that there is an ultra-close coal seam right under it with an only 0.8–1.5 m sandstone dirt band in between. The simulation study was carried out to investigate the simultaneous recovery of upper remnant coal pillars while mining the ultra-close lower panel using longwall top coal caving (LTCC). The remnant coal pillar was induced to cave in as top coal in LTCC system. Physical modelling shows that the coal pillars are the abutments of the stress arch structure formed within the overburden strata. The stability of overhanging roof strata highly depends on the stability of the remnant coal pillars. And the gob development (roof strata cave-in) is intermittent with the cave-in of these coal pillars and the sandstone dirt band. FLAC3D numerical modelling shows that the multi-seam interaction has a significant influence on mining-induced stress environment for mining of lower panels. The pattern of the stress evolution on the coal pillars with the advance of the lower working face was found. It is demonstrated that the stress relief of a remnant coal pillar enhances the caveability of the pillars and sandstone dirt band below. Keywords: Simulation, Remnant coal pillars, Ultra-close, Dirt band, Longwall top coal caving

Owing to the unearthed left maxillary fragment and left lower premolar fossil in 1950s, Changyang Cave was regarded as an important hominin site where Middle Pleistocene hominins are first discovered in southern China. However, only two bovine tooth fossils have been dated to 194 + 24–20 ka and 196 + 20–17 ka by U-series dating since 1980s. In this work, the stratigraphy of Changyang Cave was re-investigated by applying U–Th dating method for eight new tooth fossils obtained from fossil layer and two carbonate crystal samples from clay cement on the wall of this cave. New dating results showed that the ages of the two carbonate crystals are 256 and 233 ka respectively, and those of the eight tooth fossils are concentrated from 193 ka to 143 ka. Considering the ages of the two previous fossils, new carbonate crystals, and new eight tooth fossils, we suggested that the age range of Changyang hominin is between 196 and 143 ka.

In the past several years, the high frequency of cave-in failures of urban roadways has posed a serious threat to the safety of traffic, pedestrians, and existing structures and facilities ...

This chapter summarizes results of excavations at Manachaqui Cave, a stratified rock shelter site beside a pre-Hispanic paved road used by travellers moving between the Andean highlands and the Amazon Basin. During 10,000 years of use, Manachaqui served as a hunting camp, semi-permanent habitation, and a travellers’ camp and refuge from the harsh climate frequently encountered at the cloud forest edge in tropical montane forests. The site and especially its assemblages dating from the Late Preceramic Period through the Early Intermediate Period provide a rare window on the nature of human occupation in the ceja de selva, changing travel and transport technologies, strategies for information exchange using ceramic styles and decorative symbols, and the growth of sociopolitical and economic complexity among autochthonous and autonomous societies on the eastern slopes. Evidence of interregional interaction reflects human decision-making embedded within historical and social contexts, and not just interaction between “cultures” or resource zones. The functionally specialized character of Manachaqui’s material culture offers singular insights into changing modes of pre-Hispanic travel, commodity transport, and societal communication during a crucial period of emerging cultural complexity in Central Andes.

While MacNeish was excavating at Purron Cave in the Tehuacan Valley, he was frequently asked what he was finding. “Well,” ran his favorite reply, “at least the botanist had a good day.” This response reflected the fact that Purron Cave had superb plant preservation but not many highly diagnostic artifacts per square meter. The month of March was spent in testing other caves and extending our survey. Finally the authors returned to Guila Naquitz on April 14 with a larger crew and excavated there until May 10, 1966. Digging at Guila Naquitz was so soft that it was never necessary to use a tool larger than a trowel. In addition to a trowel, however, each excavator was provided with a screwdriver. The excavation of a typical square would begin with an examination of the profile and a discussion of exactly how deep the trowel would have to go to loosen the first living floor.

The article presents the results of research into 222Rn activity concentration changes and ionising radiation exposure in newly discovered parts of Bear Cave in Kletno, unknown until 2012. 222Rn activity concentration was registered at three measurement points located inside over 500-m-long newly discovered cave passages. The air in these parts of the cave is characterised by a stable temperature of about 5°C and a relative humidity of 100%. The measurements started in September 2013 and were completed by mid-July 2016. The measured data were recorded continuously, including hourly registration of 222Rn activity concentration with the use of three Polish semiconductor detectors SRDN-3a. Three data sets were obtained. Two of them, containing the same numbers of data, were recorded between 4 September 2013 and 10 July 2016 by SRDN-3a detectors no 7 and 9 located at sites no 1 and no 3, respectively. The third set comprises data registered between 27 October 2014 and 10 July 2016 by SRDN-3a probe no 8 at site no 2. Distinct daily changes in 222Rn activity concentration in the new parts of Bear Cave occur in early spring (from March to May) and in autumn (October). This observation confirms the notion that radon concentration changes depend on natural convective air exchange between the cave and the atmosphere. It has been shown that daily radon concentration changes in other seasons are irregular and rather small. The highest values of 222Rn activity concentration inside the cave are more frequent in daytime, i.e. from the morning to midday. The recorded annual mean values of 222Rn activity concentration in successive measurement years are comparable for all the three sites and range from 2690 to 3179 Bqm−3 in 2013, from 2676 to 2973 Bqm−3 in 2014, from 2587 to 2917 Bqm−3 in 2015 and from 2581 to 3719 Bqm−3 in 2016. These values exceed those recommended as maximum allowable radon concentrations in such spaces (0.5–1.5 kBqm−3) and are many times as high as the values recommended for workplaces (0.3 kBqm−3). The recorded values of 222Rn activity concentration in the air of the new parts of Bear Cave in Kletno result in a risk of exposure to a radiation dose higher than the national standard of 1 mSv per year adopted for the general public. In the most unfavourable conditions, it appears as early as after 25 hours spent inside the cave. The minimum effective dose to which a person staying inside the cave is exposed within 1 hour is 0.002 mSv, and the maximum dose is 0.04 mSv. The results of the conducted measurements demonstrate the necessity of introducing appropriate solutions, crucial in terms of radiological protection and legislation, that would minimise the risk of exposure to ionising radiation in the new parts of Bear Cave.

This work consists of the detection and quantification of the concentration levels of radioactive gas radon-222 (222Rn) of natural origin, as well as the determination of the critical points and the estimation of the effective dose absorbed by the tourists and guides inside the Jumandy cavern in Napo, Ecuador. According to the feasibility map of uranium of Ecuador, the study area is located in one of the top-priority areas for obtaining uranium, suggesting possible radioactivity in this unstudied region. The measurements were carried out from July to October of 2017, in three different monitoring points inside the cavern. The average radon concentrations measured in the cavern exceeded the maximum recommended environmental level by a factor of 28, and the effective dose absorbed by the guides exceeded the recommended maximum by a f actor of 10. Meteorological parameters such as temperature and relative humidity have an impact on the 222Rn concentrations in different parts of the cave.

The theory that spindle whorls were used in the Archaic Southwest is proposed to explain the presence of spindle whorls at the Archaic hunter-gatherer of sites Cowboy and Walters Caves. The objects...

Caves hosted in iron formations are attracting considerable interest due to their scientific and environmental value. Some of these caves are located in or near iron ore mine sites, which represent an important source of income to Brazil. However, the Brazilian legislation requires speleological studies that currently have an impact upon ore reserves and environmental licensing processes. The aim of this study was to apply conventional geotechnical empirical approaches to a cave located within the grounds of an iron ore mine in the Iron Quadrangle and validate it with numerical modelling, to ensure the method's applicability to natural caves under mining activity influence. These studies comprised the mapping of structural, geotechnical and geomechanical features of rocks hosting and surrounding the cave and to propose geotechnical domains. Field data collection covered the geotechnical parameters necessary to calculate the characteristic Mining Rock Mass Rating (MRMR) for each geotechnical domain, and to evaluate the stability conditions using the stability index or hydraulic radius of the cave. These geotechnical parameters were then used to calculate the physical parameters used in two-dimensional numerical simulations to verify the good stability conditions of the cave, corroborating the adequacy of Laubscher's diagram. The results of this study, although comprising only one cave, suggest that Laubscher's diagram is applicable for assessing the geotechnical behavior of iron ore caves.

Cave air temperature was measured at six locations in Lehman Caves (USA) for one year at hourly intervals. Lehman is a show cave in a national park, treasured for its geological and biological resources. The two monitoring locations that are off of the tour route and, also, relatively distant from the cave’s entrances displayed nearly constant air temperature during the year. The other four sites, along the tour route, show daily temperature variation as well as annual fluctuation. After visitation levels decreased in the autumn, cave temperatures lagged but eventually reached an equilibrium which demonstrates recovery in the quiet winter. The mean annual air temperature inside the Lehman Caves is significantly higher than outside (1.9 °C; 20%) which points to an anthropogenic impact. A first-order analysis indicates that anthropogenic energy consumption in the Lehman Caves—which contributes to temperature rise—is about evenly divided between lighting and human presence. The study demonstrates that cave lighting and visitation levels have important implications for responsible management of this geoheritage site.

Subterranean environments are poorly known regarding many ecological aspects, such as community structure and its response to different disturbances. To estimate the effects of ground area lost in a limestone cave community in Southeastern Brazil, the invertebrate fauna was sampled before 76% of the cave floor was submerged by the filling of a hydroeletric power plant reservoir. Then, a 2-year monitoring was conducted. A species-area curve based on empiric data was constructed and the z-value of the species-area equation was calculated, what allowed estimating the expected cave richness after flooding comparing with data obtained during the monitoring. The results support the species-area relationship hypothesis; the cave community showed a drastic reduction of richness after losing area. Furthermore, it was also possible to estimate the species richness using the species-area equation. Moreover, the cave community showed a high temporal beta diversity when comparing the community sampled before and after the inundation; this pattern becomed less pronunciated over time. A high z-value (z = 0.58) was found for the cave species-area equation, indicating that subterranean communities are even more damaged by area loss than other environments probably due to the reduced mobility of cave invertebrates and the physical isolation of this environment. The present study highlighted that area loss resulted in a drastic reduction of cave richness. Additionally, it became evident that whenever possible studies should consider the original condition of a cave community and their responses after disturbances. Such strategy is critically important for conservation purposes.

Under the condition of bad undercutting, ore pillars are easily left in undercut level in block caving method. In order to reveal the evolution mechanism of ground pressure damage induced by bad undercutting, according to the actual engineering and physical parameters of the mine, a numerical simulation model was established by finite difference software FLAC3D. In the simulation process, the extraction level excavations were excavated first according to the post-undercutting method, and the process of the undercutting were divided into three steps. In the first step, a pillar of 15 m × 5 m was formed. The stress state of extraction level excavations and overlying ore body after each step was monitored and analyzed separately, and it was compared with the actual situation of ground pressure disaster on site. The results show that: Under the influence of high horizontal in situ stress, with the development of undercutting, the special stress state in the extraction level excavations are gradually formed, which is that the compressive stress concentrates on the upper part and the tensile stress concentrates on the lower part. With the development of undercutting, the remaining ore pillar form a certain range of tension stress release area above the undercut level, which makes it difficult for overlying ore and rock to cave in, thus causing the phenomenon of “less ore and no ore” in the draw bells.

Universal existence of the filled vug or cave in carbonate reservoir complicates the fluid flow as the coexistence of free flow and porous flow. The fills in vug increase the flow resistance and affect the water invasion for a natural bottom-water reservoir. This influence was explored through experimental tests on a conceptual discrete fractured-vuggy model. This model was abstracted from Tahe Oilfield in China, in the form of isolated vugs connected by fractures network. A new scaling method was proposed for this discrete media according to the similarity of the displacement front of water drive. It was found that vug filling displays a negative role during the natural bottom-water drive. This impact depends on the geological feature of fractured-vuggy reservoir. A stronger sensitivity occurred to the fracture well-developed stratum that the vug filling made the pre-existing or new preferential corridors more significant. As a result, the systems with multiple flow paths became more “heterogeneous”. In this condition, a lower water intensity and oil viscosity can ease these adverse effects.

Earth fissures are a geologic phenomenon that mainly affects the medium with shallow surface soil and mainly developed in the Quaternary sediment cover. In the Yellow River-Qinghe River - Zhanghe River shallow buried paleochannel Band (HQZ-Qh2-II Band) on the North China Plain, 93 earth fissures are developed. Among them, 29 fissures are evolved in the Daming zone in the upper reaches of the paleochannel band. Thus, the zone belongs to a densely grouped fissure area. This study, through a series of field trenching and surveying, revealed that these earth fissures have unique plane distribution rules and profile structure features of short length (several meters to several hundred meters), shallow depth (smaller than 10 m) and good correspondence to Daming paleochannels. These basic characteristics reveal that unlike other tectonic earth fissures, Daming earth fissures are a new and unknown type of fissures, i.e., paleochannel-controlled earth fissures. Theoretical analysis of their features showed that they were formed due to the actions of gravity, primary joint factors and groundwater pumping activities and controlled by ancient river factors including paleochannels, sediments and groundwater. Among them, the process of Mode I can be summed up as “self-gravity action - tensile cracks - surface water scouring - earth fissures”. The process of Mode II is “primary join - surface water infiltration - piping - cave in - earth fissures”. The process of Mode III is “groundwater extraction - aquifer compression - inhomogeneous ground subsidence - earth fissures”. These formation mechanisms of paleochannel-induced earth fissures can be used to predict the fine distribution of shallow buried paleochannels and the overall migration process of the rivers. Thus, this kind of earth fissures is of great significance for understanding the underground paleogeomorphology (buried paleochannel) of the North China Plain and other alluvial plains of the world.

The fluid identification of carbonate reservoir is a key factor to hydrocarbon exploration and reservoir development. In order to simulate the seismic response characteristics of the cave in the carbonate reservoir, three sets of models were designed, including the caves varied in width, the caves filled with different solids, and the oil-gas-water model. The numerical simulation technique was used to carry out the forward modeling and the AVO (Amplitude varies with offset) response characteristics of the three groups of models were analyzed. The results show that the AVO characteristics can be observed when the cave reaches a certain extent in the horizontal direction. When the surrounding rock is constant, the absolute value of the intercept of the AVO curve increases with the Vp/Vs decrease. The AVO technology can effectively identify the gas cave. The effect is not obvious to water or oil cave.

Songam Cave, a magnificent dolomite cave in the Democratic People’s Republic of Korea—is also known as “A Splendid Flower Cave”—is regarded as one of the renowned natural tourist attractions with a great number of beautiful and complicated aragonitic anthodites in different forms and shapes, together with diversified underground karst features (stalactite, stalagmite, limestone columns, flowstone, rimstone dams, botryoidal forms, pool spar, concretions, underground waterfall, ponds, etc.). This paper deals with the cave formation process, the features of speleothems and other karst features in Songam Cave, which indicate that Songam Cave is a geoheritage site of high conservation significance. The geological setting of the cave and the detailed features and diversity of the speleothems provide sufficient evidence to foster an understanding of the formation and development of the karst cave. The aragonitic anthodites and the outstanding underground karst features unfolded on the ceilings and walls throughout the cave suggest that Songam Cave can also be a cave tourist attraction of high aesthetic value. Overall, Songam Cave is a geoheritage of high conservative significance because of its geological and aesthetical value.

In show caves, artificial lighting is intended to illuminate striking cave formations for visitors. However, artificial lighting also promotes the growth of novel and diverse biofilm communities, termed lampenflora, that obtain their energy from these artificial light sources. Lampenflora, which generally consist of cyanobacteria, algae, diatoms, and bryophytes, discolor formations and introduce novel ecological interactions in cave ecosystems. The source of lampenflora community members and patterns of diversity have generally been understudied mainly due to technological limitations. In this study, we investigate whether members of lampenflora communities in an iconic show cave—Lehman Caves—in Great Basin National Park (GRBA) in the western United States also occur in nearby unlit and rarely visited caves. Using a high-throughput environmental DNA metabarcoding approach targeting three loci—the ITS2 (fungi), a fragment of the 16S (bacteria), and a fragment of 23S (photosynthetic bacteria and eukaryotes)—we characterized diversity of lampenflora communities occurring near artificial light sources in Lehman Caves and rock surfaces near the entrances of seven nearby “wild” caves. Most caves supported diverse and distinct microbial-dominated communities, with little overlap in community members among caves. The lampenflora communities in the show cave were distinct, and generally less diverse, from those occurring in nearby unlit caves. Our results suggest an unidentified source for a significant proportion of lampenflora community members in Lehman Caves, with the majority of community members not found in nearby wild caves. Whether the unique members of the lampenflora communities in Lehman Caves are related to distinct abiotic conditions, increased human visitation, or other factors remains unknown. These results provide a valuable framework for future research exploring lampenflora community assemblies in show caves, in addition to a broad perspective into the range of microbial and lampenflora community members in GRBA. By more fully characterizing these communities, we can better monitor the establishment of lampenflora and design effective strategies for their management and removal.

Based on shallow geophysical data, Klanica et al. (2020, ) argued that the deepest undewater cave in the world, the Hranice Abyss (HA) had formed by epigenic karstification related to mid-Miocene opening of similar to 1 km deep Carpathian Foredeep (CF) and, hence, could be similar to 1 km deep. However, the CF subsided and the abyss was uplifted due to post mid-Miocene faulting with at least 460 m vertical offset, which makes the depth estimate of Klanica et al. (2020, ) invalid. It remains unclear under which geological circumstances the HA, if formed by epigenic karstification, could be backfilled with water column reaching similar to 400 m of height.