Small Cave Research Articles

Selective weathering of cross-bedded layers forming shelters and small caves on Akopán Tepui (Venezuela): Field, laboratory and experimental evidence about diagenesis and weathering of the Matauí Formation arenites (Roraima Supergroup, Middle Proterozoic)

South-American table-top mountains (tepuis) are formed by quartzites and sandstones of Matauí Formation belonging to the Roraima Supergroup (Lower to Middle Proterozoic). Field observations in the northern part of Akopán Tepui in Venezuela revealed that unlike the beds with flat bedding, the cross-bedded layers are commonly affected by selective weathering, expressed by depressions, shelters, and even small caves. All the arenites are fine-grained; most of them are likely of aeolian origin. Hardness measurements confirmed that the cross-bedded layers are softer than the flat-bedded or structureless beds occurring above and below them.Petrographic analysis showed that the rocks are mostly fine-grained quartzites to quartz sandstones, with original sand grains overgrown by syntaxial quartz cement and bearing signs of compaction manifested by local pressure solution. Some intergranular spaces are filled by newly-formed phyllosilicates (paragonite, locally intergrown with muscovite). In the overlying beds, no porosity was observed by microscopic study and under SEM, whereas in the underlying rocks signs of slight weathering and etching of phyllosilicates was observed, together with locally widened spaces along the grain-to-grain boundaries. The samples from cross-bedded layers display weathering, the degree of which depends on the present access of flowing water. Where water has periodical access to the arenite, it shows dissolution of quartz cement (arenization), together with complete leaching and removal of the phyllosilicates due to lateritization. The intergranular spaces are considerably widened and quartz grains bear signs of strong skeletal etching and pitting. Samples from the sites where the water access ceased show mostly leaching of phyllosilicates, with weak skeletal dissolution of quartz grains without pitting.To imitate the origin of structures observed in the field, experimental modelling was performed, using artificially layered and compacted fine-grained sands, on which sodium-silicate solution was dripped. During soaking, downward preferential penetration of the solution along the cross-bedding laminae (funnel-flow) was observed in the cross-bedded layer. The resulting structures display good lithification of horizontally layered sands and relatively poorer lithification of the cross-bedded sediment between them, showing triangular-shaped overhangs and shelters, which mimic those on the Akopán Tepui.Differential weathering of otherwise petrologically very similar arenites indicates that there had to be a difference in the initial porosity in the time of the rock denudation. A preserved porosity in the cross-bedded layers was necessary for the water/rock contact to perform dissolution.

Paleokarstic water tables and their control on reservoirs in Ordovician Yingshan Formation, Tazhong Area, Tarim Basin, NW China

Abstract Based on cores, well logging and karstic paleogeomorphology, the identification method of multi-period paleokarstic water tables and their distribution and control on reservoirs were researched of Yingshan Formation in Tazhong Area, Tarim Basin. Three periods' water tables numbered 1 to 3 have been identified from bottom to top of Yingshan Formation in Tazhong Area. The corresponding typical horizontal undercurrent zones are characterized by single karst fabrics such as sack-like dissolved vugs or subhorizontal channels, combination of various karst fabrics like pre-existing high-angle fractures intersected by small caves and subhorizontal channels, and combination of multi-layered caves and different karst fabrics of large pores. On the plane, periodical rising sea levels caused the development of No.1, No.1 and 2, No.1, 2 and 3 water tables in karst depressions, slopes and highlands respectively. As the result of the nearly horizontal occurrence of Yingshan Formation, submembers of Yingshan Formation had tiny angles with fracture-cave bodies of each period's water table, so the karst reservoirs are characterized by “crossed strata regionally and developed along the stratum locally”. The distance between water table and unconformity, thickness of horizontal undercurrent zone and average thickness of reservoir all tended to increase with the rise of karst landforms. The karst highland and slope had 2-3 periods' water tables and thicker horizontal undercurrent zones, so they had thicker and better quality reservoirs, making them favorable exploration areas.

Spar caves as fossil hydrothermal systems: Timing and origin of ore deposits in the Delaware Basin and Guadalupe Mountains, New Mexico and Texas, USA

Studies of sulfuric acid hypogene speleogenesis have contributed significantly to understanding the history of the Guadalupe Mountains of southeast New Mexico and west Texas for at least the past 12 Ma. A recently published hypothesis of supercritical CO2 spar cave genesis provides information that constrains the timing of the start of uplift to between 27 and 16 Ma, and helps to explain landscape evolution of this region for the last 185 Ma. This new speleogenetic model is summarized here and shows that U-Pb dating of crystals from different spar caves reveal different ages, and that a majority of the spar crystals were deposited during ignimbrite flare-up episodes at the end of the Basin and Range extension and onset of Rio Grande Rift extension between 36–28 Ma. During cave spar formation, geothermal gradients ranged from 50 to 70°C/km. Stable isotope data for δ13C, δ18O, and δ88Sr support that parent waters of cave spar were of low hydrothermal origin and mixed with gases emanating from shallow magma conduits; nearby outcrops of Tertiary igneous dikes of the same age as the spar support this hypothesis. Supercritical CO2 hydrothermal systems driven by magma intrusion on the western fringe of the Delaware Basin were responsible for the formation of small caves containing large, euhedral calcite crystals. Hydrothermal deposits from these types of systems are sometimes used to locate economic ore deposits, however, since this area has been uplifted, any indication of fossil hydrothermal systems, like travertine deposits, have eroded. Spar caves are remnants of hydrothermal processes and are related to and coeval with ore deposition and hydrocarbon generation in the Guadalupe Mountains and Delaware basin. These spar caves can be used as both proxies for landform evolution and to locate economic mineral deposits.

Snowy bat caves

Hibernation![Figure][1] Ussurian tube-nosed bats hibernate in tiny snow caves. PHOTO: HIROFUMI HIRAKAWA Snow provides thermal protection from extreme temperatures, a phenomenon capitalized on by polar bears and people indigenous to parts of the Arctic. But snow does not provide a cozy environment, a likely reason why more mammals have not evolved to take advantage of its protection against extreme cold. Hirakawa and Nagasaka, however, report that Ussurian tube-nosed bats ( Murina ussuriensis ) appear to create tiny snow “caves” with their bodies, which then serve as opportunistic hibernacula. After coming across anecdotal accounts of small bats being found curled up in the snow, the authors systematically searched for bats in such conditions, finding more than 30 near Sapporo, Japan. The animals displayed classic torpor positions, curled nose-to-tail, and decreased body temperatures. The authors model conditions under which the bats' bodies could create their small caves and set forth several hypotheses for hibernating conditions and scenarios. The finding that these bats use a snowy blanket for hibernation protection opens up the opportunity for many intriguing questions to be answered. Sci. Rep. 8 , 12047 (2018). [1]: pending:yes

Eogenetic Karst Control of Carbonate Reservoirs during a Transient Exposure: A Case Study of the Ordovician Yingshan Formation in the Northern Slope of the Tazhong Uplift, Tarim Basin, China

The Tazhong area of the Tarim Basin contains abundant oil and gas resources in Ordovician carbonate rocks, especially in the karst pores and caves of the Yingshan Formation. Research has indicated that the Yingshan Formation underwent a 7–11 Ma exposure during the middle Caledonian Period, resulting in large-scale karst pores and caves. However, the continental freshwater karst model cannot adequately explain the origin and distribution of karst pores and caves. In order to develop a more accurate karst model to guide petroleum exploration in the region, we analyzed the karst morphology, cave development statistics, and paleokarst environments. Karst reservoir characteristics were analyzed on the basis of the following analysis: (1) Karst morphological analyses based on core description and formation micro-imager (FMI) log analyses. The results showed that alveolar-like and Swiss cheese-like solution pores, spongy dissolution zones, pit cenotes, and small continuous karst caves developed in the Yingshan Formation. (2) The statistical analysis of pore and cave characteristics indicated that most of the karst pores and caves developed within 50 m below the unconformity where the average height of these features ranged from 0.1 to 3.0 m and their widths ranged up to 100 m. These pores and caves were commonly filled with gravel, clay, and calcite. Horizontal well and seismic attribute analysis indicated that these pores and caves were distributed over a large area. In plain view, the karst pore-cave system is comprised of cross-linked anastomosing networks of horizontal cave passages. And (3) Cathode luminescence and electron microprobe analyses suggested that clay filling within karst caves was freshwater related, while calcite filling was of seawater origin. Cements within solution pores showed three phases of luminescence, suggesting an alternating freshwater and seawater environment. Based on these characteristics, the karsts of the Yingshan Formation in the Tazhong area are interpreted to be similar to the eogenetic karsts in the Yucatan Peninsula of modern Mexico. Accordingly, this study indicates that the pore-caves of the Yingshan Formation can be subdivided into three sections. Further, the development and filling of these pore-cave sections are interpreted to have formed by eogenetic mixed-water karstification during three phases of relatively stable sea level in a coastal margin environment.

A Pleistocene landslide-dammed lake indicated by karren features (Eastern Alps, Austria)

Numerous enigmatic tube-shaped holes in the limestone ceilings of overhangs and small caves in a restricted area north of the village St. Aegyd am Neuwalde (Lower Austria) have been known at least since 1933, but so far, no detailed study concerning their origin has been conducted. The vertical holes occur in Middle Triassic limestone and they are almost perfect cylinders tapering gently to a rounded apex. Their diameters are up to 5.5 cm and their depths reach 45 cm. They occur on both sides of the Unrechttraisen valley located in the north-eastern part of the Northern Calcareous Alps. Almost identical features were described from the shores of lakes in western Ireland and termed röhrenkarren or tube karren (Simms, 2002). According to Simms' model, they have formed by condensation corrosion within air pockets trapped in limestone overhangs by rising water levels during floods. The occurrence of these features is surprising, because presently, there is no lake and so far, no palaeolake has been known from this area. Based on high-resolution airborne laser scanning data and detailed field observations, a landslide deposit was identified in a narrow section of the valley, downstream of the röhrenkarren sites. Fine-grained, partly laminated sediments with abundant dragonfly (Anisoptera) or flatworm (Turbellaria) eggs, indicative of lacustrine sediments, up to ca.100 m above present river bed. These data indicate that a landslide had dammed the Unrechttraisen River resulting in a ca.100 m deep lake. The röhrenkarren have formed due to fluctuations of the lake level, resulting from differences in river run-off and seepage through the landslide dam. Since 230Th/U-dating of calcite crusts covering some röhrenkarren was not successful, the age is not well constrained.

Geomorphological and speleogenetical observations using terrestrial laser scanning and 3D photogrammetry in a gypsum cave (Emilia Romagna, N. Italy)

Terrestrial Laser Scanning (TLS) and 3D photogrammetry techniques were used in a relatively small (100-m-long) cave developed in Messinian gypsum in Emilia-Romagna (N. Italy). The surveys were carried out to compare the results obtained by both methods in mapping small-to medium-sized morphologies. These measurements allowed reconstructing the evolution stages of the paragenetic (anti-gravitative) morphologies (ceiling channels and pendants) that carved the roof of the cave, and their relationship with local geomorphology, infilling sediments, speleothems, and structural elements. Field measurements were integrated with morphometrical analyses of the digital models that then allowed a much greater number of observations to be made. The results are a clear example of how the combination of TLS and 3D-photogrammetric data can be used to study and measure mm- to dm-scale morphologies in geomorphological studies, including caves, helping to unravel the speleogenetic and, consequently, the hydrological evolution of these environments.

A new cave locality for Astyanax cavefish in Sierra de El Abra, Mexico

The characiform fish Astyanaxmexicanus comes in two forms, a surface-dwelling morph which lives in the rivers of North and Central America and a blind, depigmented cave-dwelling morph which inhabits caves in Mexico. In recent years, this species has arguably become among the most influential model system for the study of evolutionary development and genomics in cave biology. While recent articles have analysed in great detail Astyanax genetics, development, physiology, phylogeny and behaviour, there have been comparatively few recent studies concerning its ecology and in particular its biogeography. Mitchell et al. (1977) reported the species inhabiting 29 caves in the Sierra de El Abra region. Despite the elapsing of over 40 years and the latest surge of interest in the model, not a single new cave locality had been described for the species. We describe here a new and 30th cave locality, Chiquitita Cave, inhabited by troglomorphic A.mexicanus. Their morphology, eye histology, 16S rRNA DNA sequence, and smelling capabilities are analysed. This cave represents the southernmost extension for the cave morph’s habitat within the Sierra de El Abra. Its name, Chiquitita Cave (Tiny Cave), was chosen in reference to a potential hydrologic connection to “Chica Cave” (small cave), which is among the most studied populations of Astyanax.

Didogobius janetarum sp. nov., a new cryptobenthic goby species from the Cape Verde Islands (Teleostei: Gobiidae).

Didogobius janetarum sp. nov. is described from five specimens collected from small caves and rock crevices between 12 and 20 m depth off two locations of Santiago Island, Cape Verde Islands. The species differs from all currently described congeners by the combination of the following characters: (1) 27 vertebrae, (2) second dorsal fin I + 10, (3) posterior quarter of predorsal region in front of first dorsal fin origin scaled, with several rows of cycloid scales, (4) body squamation cycloid anteriorly and ctenoid posteriorly, (5) scales in the lateral series 30-32, (6) anterior oculoscapular canal present, (7) preopercular head canal absent, (8) suborbital row 7 each a single papilla, (9) suborbital rows 2 and 4 close to orbit, and by (10) branchiostegal membranes uniformely black below preopercle, forming a V-shaped mark. Definitions for all used meristic counts are presented to serve as a reference for gobioid meristic studies. The genus is rediagnosed to accommodate recently described Didogobius species.

Paleoecology of an Upper Ordovician submarine cave-dwelling bryozoan fauna and its exposed equivalents in northern Kentucky, USA

AbstractA bryozoan-dominated fauna that inhabited small caves underneath a carbonate hardground is here described from the Corryville Formation (Upper Ordovician, Katian) exposed near Washington, Mason County, Kentucky, USA. The dominant bryozoan,Stigmatella personata(a trepostome), is found both growing downwards from the cave ceilings and upwards on the exposed hardground surface above. Another trepostome,Monticulipora, is a minor component of the cave fauna. There are few discernible anatomical differences between the bryozoan colonies that grew upwards in presumably well-lit waters and those that grew downwards in the gloomy caves. The pendant, cave-dwellingS.personatain some cases appears to have longer zooecial tubes than its exposed equivalent. The colonies ofS.personataare rounded mounds with multiple layers formed by self-overgrowth. The overgrowths in both downward and upward growing forms are marked by thin layers of sediment infilling the upper zooecial chambers in the older portion of the colony. We suggest that biofilms developed on patches of the colony where the zooids had died. Sediment adhered to these surfaces and the colony then overgrew the patches, trapping sediment within the skeleton. The bryozoan zoaria and the carbonate hardground are extensively bored by the cylindrical ichnogenusTrypanitesthat occasionally contain cylindrical calcite-filled tubes similar to “ghosts” of organic materials. Bioclaustrations are present in some of the bryozoan skeletons. This cave fauna is one of few submarine examples known from the Paleozoic. It supports the hypothesis that early cave-dwelling organisms were little differentiated from their exposed counterparts.

Az utóbbi 20 év barlangkutatási eredményei a Budai-hegységben (különös tekintettel a Rózsadomb környékére)

A Földtani Közlöny 125. 3-4. számában jelent meg összefoglaló a Budai-hegység barlangjairól (Leél-Őssy Sz. 1995). Az azóta eltelt időszakban (elsősorban a kutatási módszerek fejlődésének, és a megszaporodott hegyvidéki építkezéseknek köszönhetően) nemcsak új feltárások történtek (elsősorban a Rózsadomb térségében, ahol az 1995-ben ismert 30 km-es járathossz csaknem a duplájára, 55 km-re növekedett), hanem az itteni hipogén barlangok genetikájával, ásványvilágával kapcsolatban is számos új eredmény született. A keletkezéssel kapcsolatos új elméletek közül az elváltozott (kovás) zónákkal kapcsolatosakat, és a barlangot kioldó aszcendens termálvizek eredetével és keveredésével kapcsolatos új eredményeket kell kiemelnünk. Az akkor a Budai-hegységben ismert barlangi ásványfajok száma 15-ről 31-re emelkedett. Ebben az időszakban születtek az első konkrét eredményeket tartalmazó korhatározások is. Ezek közül több részben publikálásra került Mindszenty Andrea szerkesztette Budapest: Földtani értékek és az ember c. 2013-as könyvben. Az egész Budai-hegységben ma 239 barlangot ismerünk. Budapesten (a Pilishez tartozó Róka-hegyen lévőkkel együtt) 176 barlang található. A Rózsadomb térségében 102 barlangot kataszterizáltak az Országos Barlangnyilvántartásban. Az elmúlt 20 évben legfontosabb barlangfelfedezések a víz alatti Molnár János-barlangban, a Hideglyuk- és Harcsaszájú, valamint a Pál-völgyi-barlangban történtek: az utóbbi három barlang és a Mátyás-hegyi-barlang közötti összekötő járatok feltárásának köszönhetően, közel 31 km-es hosszával a Pál-völgyi-barlangrendszer lett Magyarország leghosszabb barlangja, megelőzve az Aggtelek-jósvafői Baradla-barlangot (beleértve a Baradla szlovákiai részét, a Domica-barlangot is). Nagy eredmény az eddig csak felszín közeli járatairól ismert Ferenc-hegyi-barlangban a Mélyszint megtalálása. Három új kisbarlang: a Citadella-kristálybarlang, a Királylaki-barlang és a József-hegyi 4. sz. barlang felfedezése pedig különösen értékes ásványkiválásai, ill. nagyon perspektivikus továbbkutatási lehetőségei miatt nagyon jelentős. Ezen kívül további 32 kisbarlangot találtak a kutatók az elmúlt 20 évben a Budai-hegységben, elsősorban a Rózsadomb térségében (1. ábra, 1. táblázat).

Model identification and control of development of deeply buried paleokarst reservoir in the central Tarim Basin, northwest China

The paleokarst reservoirs of the Ordovician Yingshan formation, rich in oil and gas, are deeply buried in the central Tarim Basin, northwest China. Dozens of imaging well-logs in this region reveal five typical paleokarst features, including solution vugs, solution-enlarged fractures, filled caves, unfilled caves and collapsed caves, as well as two typical paleokarst structures located in different paleotopographic sites, including paleokarst vadose and phreatic zones. For seismic data, the large wave impedance contrast between the paleocave system and the surrounding rocks leads to a strong seismic reflection, which is highlighted as a bead-like 'bright spot' in a seismic section. By quantitatively estimating the seismic resolution limits of deep seismic reflections, a single paleocave cannot be identified from a seismic profile, and the bead-like reflection represents an entire paleocave complex. The spectral decomposition technique was employed to depict the planar shape and semi-quantitatively measure the size of the paleocave complexes. The results indicate that the sizes of the paleokarst caves are all small, and most of the karst caves are nearly completely filled by clay and calcite. The small cave size and the effective support of cave fills for the overlying strata mean that some individual paleocaves in a paleocave complex are preserved at a burial depth of more than 6000 m. Paleotopography and faults strongly impact the distribution of paleokarst reservoirs. Well-developed paleokarst reservoirs are generally located in paleotopographic highlands and on slopes, and for a specific paleotopographic site, the distribution of paleokarst reservoirs is obviously controlled by NW-SE trending faults. The most favorable area for paleokarst development is the Tazhong No. 10 fault zone, a faulted anticline bounded by two NW-SE trending back thrusts.

First record of Eastern Cloud Forest Rat Nephelomys nimbosus (Rodentia: Cricetidae) for Colombia

Currently, four species of Nephelomys (N. childi, N. maculiventer, N. meridiensis and N. pectoralis) are known from Colombia. Here we present the first records of a fifth species, the rare Eastern Cloud Forest rat N. nimbosus, previously considered endemic to Ecuador and so far recorded only at five localities in the forests of the Eastern Cordillera. Four individuals of N. nimbosus were captured with Sherman traps at National Natural Park Cueva de los Guacharos in Huila Department, southern Colombia. Individuals were captured at two locations, a subandine primary forest at 2,000 m and at small cave ‘Cueva de los Guacharos’, at 1,900 m. Individuals were identified as N. nimbosus according to the following characteristics: ventral patche of self - colored white hairs in the gular region, ventral pelage ochraceous yellow with a golden tone, medium head-body size between 122 to 140 mm, incisive foramina between 4.6 and 5.1 mm with lateral margins rounded, posterolateral palatal pits small to big shallow and simple, hourglass shaped interorbital region, with supraorbital margins rounded or squared and a thin and delicate face. These new records increase the known species distribution by 760 kilometers to the north and present the first record of the species in Colombia. This first record of N. nimbosus for Colombia potentially extends the species distribution for northeastern Ecuadorian Cordillera and southern Colombian Cordillera. These results show the need to continue with the collection of specimens in poorly known species as N. nimbosus and in poorly known areas in Colombia, such as montane forests.

НОВЫЕ МАТЕРИАЛЫ ПО МАЛОМУ ПЕЩЕРНОМУ МЕДВЕДЮ URSUS ROSSICUS BORISSIAK, 1930 СРЕДНЕГО НЕОПЛЕЙСТОЦЕНА КУРТАКСКОГО АРХЕОЛОГИЧЕСКОГО РАЙОНА

New material on a small cave bear from Berezhekovo locality in Kurtak archeology district (NorthMinusinsk basin) is described. Material is represented by the upper and lower jaws fragments. This materials described is identical to earlier known finds from this locality. The available data allows us to assume that the population of the small cave bear of southern Siberia remained morphologically homogeneous during the middle and late Neopleistocene.

First record of the “small cave bear” in Bulgaria and the taxonomic status of bears of the Ursus savini Andrews – Ursus rossicus Borissiak group

Abstract The discovery of rich, well preserved skull material in the latest Middle Pleistocene deposits of Mishin Kamik cave (N-W Bulgaria) presents an opportunity for a new analysis of the taxonomy and the phylogeny of the so called “small cave bears”. Not all the small cave bears known would have necessarily had a common origin, the size decrease could be related in a number of cases to a parallelism. The bear from Mishin Kamik is identical with “Ursus rossicus” Borissiak from Krasnodar (S. Russia). Both these samples must be referred to U. savini Andrews from Bacton near Cromer (England). The specimens from Krasnodar and Mishin Kamik could be classified as U. sa. rossicus, a late form of the species. This species may have affinities with some Middle Pleistocene Siberian forms. U. savini is a small but very robust spelaeoid bear which is more advanced in a number of features than U. deningeri. In several aspects it attained the evolutional adaptations of the cave bears of the U. spelaeus-U. ingressus group and represents an independent lineage of spelaeoid bears. The Mishin Kamik population was adapted to a mosaic landscape of forests and open areas in hilly terrain. This bear had well developed grazing adaptations but had weak motor abilities.

Redescription of the monotypic genus Cubacanthozomus (Schizomida: Hubbardiidae) and conservation status of its type-species

Some of the taxonomic characters originally argued for the Cuban monotypic genus Cubacanthozomus Teruel, 2007, are unsubstantial. Others were misinterpretations of drawings given in the original description of Schizomus rowlandi Dumitresco, 1973, the only source of taxonomic information on which Teruel (2007) based the new genus. Recently a new collection of this species was made in a small cave about 350 m from one of the caves mentioned in the original description: Cueva de Majana, Baracoa municipality, Guantánamo province. On the basis of new morphological evidence found during examination of two females and a male, both the genus Cubacanthozomus and its type-species are herein redescribed. Cueva de Majana is recognized as the true type locality of C. rowlandi, which male holotype was erroneously listed as being collected in a cave from central Cuba, 600 km away. Additional data are provided on the morphology, natural history and conservation status of C. rowlandi, which is now being proposed as an endangered species.

A new extinct species of large bullfinch (Aves: Fringillidae: Pyrrhula) from Graciosa Island (Azores, North Atlantic Ocean)

A new species of extinct bullfinch, Pyrrhula crassa n. sp., is described from bones found in Furna do Calcinhas, a small cave situated at Caldeira, a volcano located in the southeastern portion of the Graciosa Island (Azores archipelago, North Atlantic Ocean). It is the first extinct passerine bird to be described from this archipelago. Both skull and post-cranial bones are larger in the new species than in its relatives, the Eurasian Bullfinch (P. pyrrhula) and the Azores Bullfinch or “Priolo” from São Miguel Island (P. murina), the new species being the largest known in this genus. The morphology of its humerus and the estimated wing length and surface area seem to indicate a flying ability similar to that of the extant P. murina. The possible sources of colonization of the genus into Azores, causes and chronology of extinction of the new species are discussed

Radiocarbon Constraints on the Age of the World’s Highest-Elevation Cave-Bear Population, Conturines Cave (Dolomites, Northern Italy)

AbstractWe report radiocarbon (14C) dates on bone samples of Ursus ladinicus, a small cave bear species well adapted to a life in the mountains, whose remains were found in Conturines Cave. Located at 2775 m asl in the Dolomites of northern Italy, this cave is by far the highest known cave bear site worldwide. Eleven 14C dates obtained by the Belfast and Oxford laboratories on samples showing good collagen preservation yielded consistent ages in excess of 46–50 ka BP. These results show that contrary to the previously held view these cave bear remains are older than Marine Isotope Stage 3, and likely date from a warm climate period with a high treeline, possibly the Last Interglacial.

Cryptic life stages in scyphozoan jellyfish: Larval settlement preferences of the South American sea nettle Chrysaora plocamia

Bloom forming jellyfish have received considerable attention over the past years. And while the eye-catching medusa is well studied, little is known about its small, inconspicuous and hard to find polyp-counterpart. In fact, so hard to find that polyps of most scyphozoan species have not been detected in their natural habitat. Considering the important roles polyps may play in jellyfish bloom formation, identifying the criteria for planulae to select suitable microhabitats that warrant the well-being and survival of polyps is a key issue. In order to find clues on the characteristics of natural habitats of Chrysaora plocamia polyps, settlement preferences of planulae were determined in a laboratory study. The settlement density, geotaxis and colour preferences were assessed, using a three-dimensional substrate that provided settlement areas of different orientation, levels of shelter and colours. Planulae exclusively colonized horizontal surfaces in an upside down position, tended to settle in sheltered areas and showed significant preferences for green and red substrates. If planulae of the jellyfish C. plocamia display similar preferences in the field, polyps should be found on protected substrates that provide overhangs, small caves, crevices or roof-surfaces, and green or red substrates, like stipes and blades of macroalgae, or crustose coralline algae.

Paleokarst of the Lianglitage Formation related to tectonic unconformity at the top of the Ordovician in the eastern Tazhong Uplift, Tarim Basin, NW China

The Lianglitage Formation (also named Lianglitag Formation) is an important hydrocarbon reservoir in the Tarim Basin; the reef and shoal facies of this formation have previously been extensively investigated. The paleokarst of the formation related to a tectonic unconformity at the top of the Ordovician (Tg5) has, however, not been widely investigated. In this paper, we undertake a comprehensive study of the paleokarst by an integrated analysis of seismic data, well‐logging data, and core data. Several geomorphologic units that formed at the end of the Ordovician period are identified, including a fault‐thrust uplift high, inter‐uplifts sag, uplift platform, and fault‐thrust anticline; these units are controlled by west–east and northwest–southeast striking faults. The thickness of erosion is estimated to be 200 to 700 meters. The paleokarst is characterized by large and small caves, dense vugs, and dissolution fractures. Large caves predominantly developed in exposed areas and on the slopes. Dense vugs and small caves, features that contribute to premium hydrocarbon reservoirs, are generally tens of meters away from the unconformity, whereas dissolution fractures, predominantly filled by mud and silts, are situated in close proximity to the unconformity and faults. Four karst zones can be identified from vertical profiles: weathered crust (1–2 m thick), vertical infiltration zone (tens of meters thick), phreatic zone (tens to hundreds of meters thick), and a bottom zone that is largely unaffected by karstification. The karst of the Lianglitage Formation at the end of the Ordovician was mainly controlled by tectonic movement, paleogeomorphology, lithofacies, faults, and fractures. The karstification process is summarized in a karst model.