Large Cave Research Articles

Characteristics of Changchengian rifts in southern margin of North China Craton and its hydrocarbon geological conditions

The Meso-Neoproterozoic strata are wildly distributed in North China Craton (NCC), of which Changchengian strata are most widely developed. Taking Changchengian strata in south margin of NCC as the study object, and combined with comprehensive analysis of isotopic chronology and petrology, it can be concluded that the Xiong'er rift is a plume rift which responds to breakup of Columbia supercontinent. Seismic data shows that Changchengian rifts are developed in the Qinshui Basin and the southern part of Ordos Basin covered by Phanerozoic strata, respectively are large-scale graben rifts and half-graben rifts. Aero magnetic data indicates that a NE-trending rift is developed in the west of the Xiong'er rift, and the Qinshui Basin rift is the extension of the north branch of the Xiong'er rift. The filling process of Changchengian rifts can be divided into four stages: the early rifting stage developing thick andesitic volcanic rocks, the late rifting stage developing large suite of coarse clastic sedimentary rocks, the depression stage developing fine clastic rocks, and the epeiric sea stage developing carbonate rocks. The dark argillaceous rocks are developed in Cuizhuang Formation and Chenjiajian Formation during the depression stage, and the black shale in Cuizhuang Formation is the effective source rocks. The bitume is filled in fractures of dolomite in Luoyukou Formation, as well as dissolution pores and large caves in Longjiayuan Formation. The argillaceous sandstone and muddy limestone of Lower Cambrian is the effective cap rocks, which can form an potential accumulation assemblage of Changchengian strata with underlying source rocks of Cuizhuang Formation and reservoirs of Luoyu Group, and this assemblage may be still effective at present.

The application of N2 huff and puff for IOR in fracture-vuggy carbonate reservoir

In Tahe Oilfield, Tarim Basin, NW China, although the carbonate reservoir displays poor porosity and permeability in matrix, the fractured-vuggy system distributes in a random, discreet and discontinuous way, which could yield high oil rates once the fractured-vuggy system is connected by production wells. The fractured-vuggy carbonate reservoirs consist a group of large caves which are inter-connected with high permeable fractures. Due to the lack of powerful and suitable IOR (Improved Oil Recovery) strategies, the depletion recovery is usually applied at the beginning for a fractured-vuggy carbonate reservoir. During the depletion process, the elastic energy of the cave formation starts to decrease, which will cause insufficient liquid supply. Then, the water was injected to improve the oil recovery when the energy (pressure) is the main reason for the insufficient production performance of the well. However, if the high water cut is the main reason, alternative IOR techniques such as the N2 huff and puff method could be utilized. This paper mainly researches the application of N2 huff and puff in a fracture-vuggy carbonate reservoir, where the critical parameters for designing the N2 huff and puff process are proposed. In addition, the proposed method is applied to Well SX to serve as a practical example. Based on the three-dimensional (3D) quantitative sculpture geological model and the dynamic production analysis, the critical parameters for N2 huff and puff are obtained by numerical simulation. In addition, the obtained parameters are validated by the field data, which proves that the proposed method can be applied to design the critical parameters for simulating the N2 huff and puff process in a fractured-vuggy carbonate reservoir.

Cryptic diversity of stygobiotic shrimp genus Xiphocaridinella Sadowsky, 1930 (Crustacea: Decapoda: Atyidae): the first case of species co-occurrence in the same cave system in the Western Caucasus.

DNA barcoding of stygobiotic shrimps of the genus Xiphocaridinella Sadowsky, 1930 (Crustacea: Decapoda: Atyidae) collected in underground streams flowing inside two neighboring large karst caves (Otap and Abrskil сaves) revealed the presence of two distinct genetic lineages representing the first case of species co-occurrence in the Western Caucasus. The paper presents the complete morphological re-description of stygobiotic atyid shrimp Xiphocaridinella ablaskiri (Birštein, 1939) and the description of a new species using genetic and morphological analysis. Other known cases of co-occurrence of several stygobiotic shrimp species in the same cave system as well as new genetic data (COI mtDNA) on Western Caucasian species of the genus Xiphocaridinella are discussed in the paper.

The stone and bone artifacts from Asx̂aana-x̂ Cave, Islands of the Four Mountains, Alaska

AbstractAsx̂aana-x̂ Cave in the Islands of the Four Mountains, Alaska, was excavated in 1990. The cave contained the remains of Unangan mummies and their grave goods including textile, wood, bone and stone artifacts. These mummies were buried between AD 1250 and AD 1780-1790. The mummies were distributed in three distinct areas in the front, middle and back of the large cave. The textile and wooden artifacts and their distribution have been described in earlier publications. The stone artifacts include end blades, adzes, ulus and hammerstones plus an oil lamp and a small figurine; among the bone artifacts are whale bone planks and scapulae, rods and shafts, harpoon heads and labrets. These artifacts are typical of artifacts in the Aleutian Islands, while their distribution continues to strengthen the idea of a disjunct distribution of artifacts in the cave, which I interpret as being due to different social groups using the three areas of the cave for their burials.

A new workflow to improve the carbonate reservoir types discrimination combing the empirical model decomposition and energy entropy classification methods

Classification and well-logging evaluation of carbonate reservoir rock is very difficult. On one side, there are many reservoir pore spaces developed in carbonate reservoirs, including large karst caves, dissolved pores, fractures, intergranular dissolved pores, intragranular dissolved pores, and micropores. On the other side, conventional well-logging response characteristics of the various pore systems can be similar, making it difficult to identify the type of pore systems. We have developed a new reservoir rock-type characterization workflow. First, outcrop observations, cores, well logs, and multiscale data were used to clarify the carbonate reservoir types in the Ordovician carbonates of the Tahe Oilfield. Three reservoir rock types were divided based on outcrop, core observation, and thin section analysis. Microscopic and macroscopic characteristics of various rock types and their corresponding well-log responses were evaluated. Second, conventional well-log data were decomposed into multiple band sets of intrinsic mode functions using empirical mode decomposition method. The energy entropy of each log curve was then investigated. Based on the decomposition results, the characteristics of each reservoir type were summarized. Finally, by using the Fisher discriminant, the rock types of the carbonate reservoirs could be identified reliably. Comparing with conventional rock type identification methods based on conventional well-log responses only, the new workflow proposed in this paper can effectively cluster data within each rock types and increase the accuracy of reservoir type-based hydrocarbon production prediction. The workflow was applied to 213 reservoir intervals from 146 wells in the Tahe Oilfield. The results can improve the accuracy of oil-production interval prediction using well logs over conventional methods.

First record of subterranean rissoidean gastropod assemblages in Southeast Asia (Mollusca, Gastropoda, Pomatiopsidae)

In February 2017 we investigated several caves and karstic springs in Laos for the presence of underground freshwater gastropod species. We report previously unrecorded freshwater gastropod assemblages in the largest cave in Laos, Tham Khon Dôn, and in the third largest cave, Pha Soung, in Khammouane Province, with single finds in Na Li Cave (Khammouane Province), an unnamed cave near Vieng Thong (Bolikhamsay Province) and a small karst spring near Phonsavan (Xianghouan Province). All 15 species recorded and described herein are new to science. Four species are assigned to the new genusPseudoiglica:P. pseudoiglicasp. n.,P. olsavskyisp. n.,P. kameniarisp. n., andP. phonsavanicasp. n.Three species are assigned to the new genusThamkhondonia:T. mouretisp. n.,T. vacquieisp. n., andT. smidaisp. n.Eight species are assigned to the genusTriculaBenson, 1843:T. valenasisp. n.,T. davisisp. n.,T. spelaeasp. n.,T. lenahanisp. n.,T. reischuetzorumsp. n.,T. phasoungensissp. n.,T. bannaensissp. n., andT. viengthongensissp. n.

First record of subterranean rissoidean gastropod assemblages in Southeast Asia (Mollusca, Gastropoda, Pomatiopsidae)

In February 2017 we investigated several caves and karstic springs in Laos for the presence of underground freshwater gastropod species. We report previously unrecorded freshwater gastropod assemblages in the largest cave in Laos, Tham Khon Dôn, and in the third largest cave, Pha Soung, in Khammouane Province, with single finds in Na Li Cave (Khammouane Province), an unnamed cave near Vieng Thong (Bolikhamsay Province) and a small karst spring near Phonsavan (Xianghouan Province). All 15 species recorded and described herein are new to science. Four species are assigned to the new genusPseudoiglica:P.pseudoiglicasp. n.,P.olsavskyisp. n.,P.kameniarisp. n., andP.phonsavanicasp. n.Three species are assigned to the new genusThamkhondonia:T.mouretisp. n.,T.vacquieisp. n., andT.smidaisp. n.Eight species are assigned to the genusTriculaBenson, 1843:T.valenasisp. n.,T.davisisp. n.,T.spelaeasp. n.,T.lenahanisp. n.,T.reischuetzorumsp. n.,T.phasoungensissp. n.,T.bannaensissp. n., andT.viengthongensissp. n.

Chronology of the cave interior sediments at Gran Dolina archaeological site, Atapuerca (Spain)

The so-called “Gran Dolina site” (Atapuerca mountain range, N Spain) is a karstic cavity filled by sediments during the Pleistocene, some of which contain a rich ensemble of archaeological and paleontological records. These sediments have contributed significantly to our understanding of early human dispersal in Europe but, in contrast, older, interior facies deposits have received much less of attention. The stratigraphy of Gran Dolina reveals an abrupt sedimentary change of interior to entrance facies from bottom to top, reflecting a significant paleoenvironmental change that promoted the accumulation of sediments transported from the vicinity of the cave by water or “en masse”. Since the major magnetic polarity reversal known as the Matuyama-Brunhes boundary (0.78 Ma) was detected within the TD7 unit in the middle of the stratigraphic section, we carried out a new combined paleomagnetic, radiometric (U-Pb), and electron spin resonance (ESR) dating study of the lower part of the sequence in order to constrain the chronology of the interior facies at Gran Dolina. U-Pb analysis of speleothems did not produce age information as the samples proved to be extremely unradiogenic. The magnetic stratigraphy of the cave interior sediments reveals a dominant reverse magnetic polarity, coherent with a Matuyama age, and interrupted by a normal polarity magnetozone interpreted as the Jaramillo Subchron (1.0–1.1 Ma). ESR ages on quartz grains from the upper part of the interior facies sediments are coherent with such an interpretation. We conclude that the fluvial deposits (interior facies) that constitute the cave floor began accumulating before 1.2 Ma. The development of large cave entrances at Gran Dolina occurred shortly after the Jaramillo Subchron but before ca 900 ka ago.

Gigantic lion, Panthera leo, from the Pleistocene of Natodomeri, eastern Africa

AbstractThe partial skull of a lion from Natodomeri, northwest Kenya is described. The Natodomeri sites are correlated with Member I of the Kibish Formation, dated to between 195 ka and ca. 205 ka. The skull is remarkable for its very great size, equivalent to the largest cave lions (Panthera spelaea [Goldfuss, 1810]) of Pleistocene Eurasia and much larger than any previously known lion from Africa, living or fossil. We hypothesize that this individual represents a previously unknown population or subspecies of lion present in the late Middle and Late Pleistocene of eastern Africa rather than being an indication of climate-driven size increase in lions of that time. This raises questions regarding the extent of our understanding of the pattern and causes of lion evolution in the Late Pleistocene.

Late Pleistocene songbirds of Liang Bua (Flores, Indonesia); the first fossil passerine fauna described from Wallacea.

BackgroundPasserines (Aves: Passeriformes) dominate modern terrestrial bird communities yet their fossil record is limited. Liang Bua is a large cave on the Indonesian island of Flores that preserves Late Pleistocene–Holocene deposits (∼190 ka to present day). Birds are the most diverse faunal group at Liang Bua and are present throughout the stratigraphic sequence.MethodsWe examined avian remains from the Late Pleistocene deposits of Sector XII, a 2 × 2 m area excavated to about 8.5 m depth. Although postcranial passerine remains are typically challenging to identify, we found several humeral characters particularly useful in discriminating between groups, and identified 89 skeletal elements of passerines.ResultsAt least eight species from eight families are represented, including the Large-billed Crow (Corvus cf. macrorhynchos), the Australasian Bushlark (Mirafra javanica), a friarbird (Philemon sp.), and the Pechora Pipit (Anthus cf. gustavi).DiscussionThese remains constitute the first sample of fossil passerines described in Wallacea. Two of the taxa no longer occur on Flores today; a large sturnid (cf. Acridotheres) and a grassbird (Megalurus sp.). Palaeoecologically, the songbird assemblage suggests open grassland and tall forests, which is consistent with conditions inferred from the non-passerine fauna at the site. Corvus cf. macrorhynchos, found in the Homo floresiensis-bearing layers, was likely part of a scavenging guild that fed on carcasses of Stegodon florensis insularis alongside vultures (Trigonoceps sp.), giant storks (Leptoptilos robustus), komodo dragons (Varanus komodoensis), and probably H. floresiensis as well.

Spacio-Temporal Distribution and Tourist Impact on Airborne Bacteria in a Cave (Škocjan Caves, Slovenia)

(1) Background: Airborne microbes are an integral part of a cave ecosystem. Cave allochtonous airborne microbiota, which occurs mainly during aerosolization from an underground river, from animals, and from visitors, is particularly pronounced in show caves. The impacts of tourists and natural river aerosolization on the cave air were estimated in large cave spaces within the Škocjan Caves; (2) Methods: Simultaneously with the measurements of atmospheric parameters, cultivable airborne bacteria were impacted, counted and identified using MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry); (3) Results: A mix of bacteria typically associated with humans and with natural habitats, including a large percentage of non-identified isolates, was found in the cave air. Few of the isolates were attributed to Risk Group 2. A strong positive correlation between tourist numbers and the rise in the concentration of airborne bacteria was indicated. Concentration of airborne bacteria rises to particularly high levels close to the underground river during periods of high discharge. A 10-times lower discharge reflected an approximately 20-times lower concentration of airborne bacteria; (4) Conclusions: Caves that are open and visited contain a diverse airborne microbiota originating from different sources. Enormous cave chambers that display relatively dynamic cave climate conditions do not normally support the enhancement of airborne bacterial concentrations.

Bat population censusing with passive acoustics

Passive acoustic monitoring is a widely used method to identify bat species and determine spatial and temporal activity patterns. One area where acoustic methods have not yet been successfully applied, however, is in determining population counts, especially from roosts. Typically, most roost counts are obtained with thermal imagery that may be prohibitively expensive for many natural resource managers or require complex computer programming. Here, we demonstrate a new acoustic technique to estimate population size of Brazilian free-tailed bats (Tadarida brasiliensis) emerging from large cave colonies. Data were acquired across multiple nights and at 9 cave locations with different roost structures and flight behavior profiles. We used a single microphone to monitor echolocation activity and simultaneously recorded the emerging bats with thermal video. Bat abundance counts were determined from a single video frame analysis (every 10 s) and were compared to different acoustic energy measures of a 1-s long acoustic sequence recorded at the time of the analyzed video frame. For most cave locations, linear regression models successfully predicted bat emergence count based on acoustic intensity of the emerging stream. Here, we describe our method and report on its application for counting bats from different roost locations.

Inland notches: lithological characteristics and climatic implications of subaerial cavernous landforms in Israel

AbstractInland notches, are elongated concave‐shape indentations that develop on the carbonate rocky cliffs of mountainous zones, down to the desert fringe. These rock shelters form as a result of the interaction between specific petrologic characteristics and climatic controls, emphasizing the importance of environment upon rock decay. Inland notches are shaped due to slight differences (1–15%) in the porosity of the visor and cavity bed: the cavity bed is more porous, so more likely to erode by exfoliation and dissolution. Thus, the cavity bed retreats at a faster rate compared to the slower subaerial dissolution of the visor bed, until a critical point is reached where the visor collapses. In Israel, inland notches inhabit the same lithostratigraphic units as do large caves. The vast majority (71%) of inland notches are formed in hard, dense, and crystalline limestone deposited throughout the Turonian age. Another 27% are cut into the dolomitic sequence of the upper Albian and lower Cenomanian. The rest (2%) are dispersed in the various formations of the Cenomanian and Eocene eras. Notches are most common in semi‐arid and in Mediterranean climates but mainly in areas with annual rainfall of between 400 mm and 850 mm. In more humid areas (> 900 mm/yr) notches are negligible or completely absent, due to the rapid rate of chemical dissolution of carbonate rocks. In the desert fringe (200–300 mm/yr), mechanical decay is accelerated and notches exhibit disintegration processes, visor collapse, and rock falls. In the desert area (< 200 mm/yr), salt decay replaces the chemical decay characteristic of inland notches, encouraging tafoni formation. In addition, notches form through fluvial activity or on account of greater petrophysical differences between consecutive beds; i.e. elongated cavities may form in soft rocks, shaded by harder visors or crusts. Copyright © 2017 John Wiley & Sons, Ltd.

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.

From Chauvet to Lascaux: 15,000 Years of Cave Art

The earliest art of Western Europe was evolving together with the Homo sapiens population of hunter-gatherers in the glacial environment of the northern hemisphere over the entire Upper Paleolithic (36–13 ka BP). The most important rock art sites, such as Altamira and La Garma in Spain, and Lascaux, Niaux, Cussac, and Chauvet in France, are relevant to the socio-cultural behavior and needs of anatomically modern humans. In this paper, we intend to identify certain changes in the symbolic language, in the ways animals are rendered, and in the layout of artistic space over 15,000 years separating the two key rock art galleries with the best preserved representations: Chauvet (36 ka BP) and Lascaux (21 ka BP). Chauvet, discovered in 1994, is located in the Ardeche Valley near the Mediterranean coast. In this large cave, numerous new kinds of Upper Paleolithic rock art were documented, spanning two distinct occupation periods between 37,000–30,000 years ago. The early stage is the Aurignacian with black zoomorphic paintings, dating to 37,000–33,500 BP. Lascaux, discovered in 1940, is situated in the Vezere Valley, 120 km away from the Atlantic coast, among a large cluster of rupestral art sites in caves and rock shelters. Today, the cave is closed for the public because intense tourist activities over many years from its discovery until 1963 have disrupted the microclimate of the cave and endangered the paintings.

Isotopic characterization of cave environments at varying altitudes on the eastern Adriatic coast (Croatia) – Implications for future speleothem-based studies

An important step in the implementation of paleoclimate reconstructions from speleothems (cave carbonate deposits) is to evaluate the sensitivity of the host cave environment to regional climate. Accordingly, we studied three caves at different altitudes (74m, 570m and 1250m a.s.l.) along a transect from the Dalmatian islands to Velebit Mountain peaks in coastal Croatia to characterize their environments in terms of each cave’s suitability to host speleothems that would be capable of yielding robust paleoclimate reconstructions. We conducted cave microclimate (2-years) and dripwater (1-year) monitoring and analysed the isotopic composition of precipitation, cave dripwater and modern spelean calcite. As for the water isotopic imprints, the isotopic values of meteoric waters reaching the two lower-altitude caves, in spite of an altitude difference of 500m, lie on local meteoric water lines (LMWLs) of similar slope and intercept (δ2H=6.61×δ18O+4.92 and δ2H=6.69×δ18O+6.86). Their slopes lower than that of GMWL indicate enhanced evaporation during the warm season. As expected, the LMWL of the highest cave region (δ2H=7.83×δ18O+14.45) resembles the slope of the GMWL, but the values of deuterium excess obtained for all three caves (between 15.2‰ and 16.6‰) match that of western Mediterranean-sourced waters (∼15‰). Monthly d-excess values suggest Atlantic-sourced air masses can reach the sites throughout the year but never dominate the rainfall composition. The altitude effect was noted both in precipitation and in dripwater isotopic composition, but with notably different Δδ18O/100m gradients (−0.33‰ and −0.11‰, respectively). Stable isotope variations of the dripwaters in all caves were attenuated in relation to the rainwater, even those of the drip sites with fracture-flow behaviour.Based on stable cave microclimate conditions, relatively steady discharges, and modern calcite apparently precipitated at or close to isotopic equilibrium with dripwater, the two caves at lower altitudes show the greatest potential for future paleoclimate studies. The cave at the highest altitude experiences large cave air temperature amplitudes (5.3°C) and pronounced ventilation, making the isotopic signal susceptible to kinetic fractionation which might preclude quantification of environmental changes, but on the other hand it accentuates isotopic events, making them easier to identify.

Reconciling Mining with the Conservation of Cave Biodiversity: A Quantitative Baseline to Help Establish Conservation Priorities.

Caves pose significant challenges for mining projects, since they harbor many endemic and threatened species, and must therefore be protected. Recent discussions between academia, environmental protection agencies, and industry partners, have highlighted problems with the current Brazilian legislation for the protection of caves. While the licensing process is long, complex and cumbersome, the criteria used to assign caves into conservation relevance categories are often subjective, with relevance being mainly determined by the presence of obligate cave dwellers (troglobites) and their presumed rarity. However, the rarity of these troglobitic species is questionable, as most remain unidentified to the species level and their habitats and distribution ranges are poorly known. Using data from 844 iron caves retrieved from different speleology reports for the Carajás region (South-Eastern Amazon, Brazil), one of the world's largest deposits of high-grade iron ore, we assess the influence of different cave characteristics on four biodiversity proxies (species richness, presence of troglobites, presence of rare troglobites, and presence of resident bat populations). We then examine how the current relevance classification scheme ranks caves with different biodiversity indicators. Large caves were found to be important reservoirs of biodiversity, so they should be prioritized in conservation programs. Our results also reveal spatial autocorrelation in all the biodiversity proxies assessed, indicating that iron caves should be treated as components of a cave network immersed in the karst landscape. Finally, we show that by prioritizing the conservation of rare troglobites, the current relevance classification scheme is undermining overall cave biodiversity and leaving ecologically important caves unprotected. We argue that conservation efforts should target subterranean habitats as a whole and propose an alternative relevance ranking scheme, which could help simplify the assessment process and channel more resources to the effective protection of overall cave biodiversity.

Taxonomic, phylogenetic and ecological diversity of Niphargus (Amphipoda: Crustacea) in the Hölloch cave system (Switzerland)

Groundwater belongs to the spatially most extensive, but least explored freshwater systems. On a global scale, the species richness of several subterranean invertebrate taxa parallels species richness found in surface waters, while on a local scale species richness hardly exceeds 20 species. This results in a high contribution of groundwater ecosystems to regional β- and γ-diversity, and to a smaller degree to α-diversity, and deserves focused attention. In general, more species are to be found in large cave systems. The second largest cave system in Europe is Hölloch in Switzerland. In this paper we revised the taxonomic, phylogenetic and ecological diversity of the amphipod community in the Hölloch cave system. While previous records listed five geographically widespread species of the genus Niphargus for this cave system, we could not confirm the presence of any of those species, but rather found three highly distinct species new to science. In this paper we describe Niphargus styx sp. nov., Niphargus murimali sp. nov., and Niphargus muotae sp. nov., and suggest that previous records from that cave were probably misidentifications. Although amphipod species richness in this cave system seems to be lower than previously thought in terms of absolute numbers, the cave retained its regional and international importance in terms of nature conservation for multiple reasons. First, all newly described species are probably endemic to this cave system. Second, they are phylogenetically distantly related and exhibit moderate to high phylogenetic diversity. Third, the species, as inferred from their functional morphology, are also ecologically highly divergent. Based on geographic distribution of their nearest relatives, we hypothesize that the cave system was most likely independently colonized from North, West and South and that the pre-adapted ancestors occupied different ecological niches within the system.http://zoobank.org/urn:lsid:zoobank.org:pub:A19309E5-C06B-4844-A4D8-7571F05F25C9

Features and classified hierarchical modeling of carbonate fracture-cavity reservoirs

Abstract Taking the Ordovician fracture-cavity carbonate reservoir of Tahe oilfield, Tarim Basin as an example, the fracture-cavity reservoir has been classified according to the type and size of reservoir space, and a 3-D geological model of fracture-cavity reservoirs was built according to their types and classes. Based on core, drilling, logging and seismic data, the fracture-cavity reservoir was divided into four types, namely cave, dissolved pore, fracture and Matrix block types, in which the cave was subdivided into two subtypes, large cave and small cave; and the fracture was subdivided into four subtypes, large scale fracture, meso-scale fracture, small scale fracture and microfracture. The large cave model was established using deterministic method via seismic truncation and pattern modification. The small cave model was built using the method of multiple-point geostatistical simulation with large cave model as the training image. The dissolved pore model was built using sequential Gaussian simulation. The large scale fracture model was established using the deterministic method of manual interpretation, meso-scale fracture model was built using deterministic method of ant tracking, the small scale fracture model was built using stochastic object-based modeling. The micro-fracture and Matrix block have no discrete distribution model established because of their poor storage quality. Then the different types of reservoir space models were merged into one model to get the discrete distribution model of typical fracture-cavity unit. The application in Tahe blocks 6 and 7 showed that this classified hierarchical modeling improved the reservoir model precision, guided the water-flooding effectively and advanced the development efficiency.

Kinematic analysis and experiment of planetary five-bar planting mechanism for zero-speed transplanting on mulch film

A novel seedling transplanting mechanism with planetary five-bar was developed in order to solve some problems when transplanting seedlings on mulch film, such as a large cave diameter, a low proportion of upright seedlings, and inconsistent planting depths, which seriously restrict the development of transplanting equipment used in dryland agriculture. The planetary five-bar structure of transplanting mechanism was designed based on analysis of the seedling transplanter on mulch film. The kinematics model of the transplanting mechanism was established and the optimal parameters of the transplanting mechanism were obtained by satisfying the motion trajectory conditions. Subsequently, the virtual prototype of transplanting mechanism was developed, and the simulation of motion trajectory was illustrated. Finally, the physical prototype of the transplanting mechanism was assembled and tested with the high-speed photography. The simulation results indicated that the desired “spindle” trajectory for the duckbill can be obtained, of which the height was 350 mm, and the diameter of the planting cave was 32 mm. The experimental results showed that the diameter of the planting cave was less than 70 mm, the seedling perpendicularity qualification rate reached 96%, the film injury rate was less than 0.5%, and the hanging membrane phenomenon was avoided. Therefore, the proposed transplanting mechanism can meet the requirements for a mulch-film transplanting machine. Keywords: seedling transplanting, mulch-film, planetary five-bar mechanism, zero-speed transplanting, parameter optimization DOI: 10.3965/j.ijabe.20160904.2073 Citation: Liu J D, Cao W B, Tian D Y, Tang H Y, Zhao H Z. Kinematic analysis and experiment of planetary five-bar planting mechanism for zero-speed transplanting on mulch film. Int J Agric & Biol Eng, 2016; 9(4): 84－91.