Karst Fissure Research Articles

Quantification and reduction of groundwater model structural uncertainty based on Gaussian process regression

Nowadays, the main analysis method for groundwater model structural uncertainty is the Bayesian model averaging (BMA) method. But BMA suffers from the difficulty of model weight estimation, which makes its application infeasible. More attention is recently paid to the data-driven based model structural error analysis method. In this paper, the groundwater model structural error is statistically learnt based on Gaussian process regression, and then the parameters of the groundwater model and statistical model are identified simultaneously by combining the DREAMzs and Gaussian process regression algorithms. With this method, the uncertainty of groundwater model parameters and prediction results are analyzed. In addition, a synthetic numerical simulation of seawater intrusion in a karst fissure area and a solute transport column experiment are taken as case studies. In contrast with the uncertainty analysis without considering the model structural error, the impact of parameter compensation is significantly reduced by considering the model structural error. Moreover, the model prediction performance is also improved. Therefore, based on the model structural uncertainty analysis method proposed in this paper, the uncertainty of groundwater modeling can be reduced to some extent, as well the reliability of groundwater model prediction can be improved.

Geometric morphology and soil properties of shallow karst fissures in an area of karst rocky desertification in SW China

Serious soil erosion and an extremely low rate of soil formation leads to a thin layer of surface soil that makes tree growth difficult in areas of karst. Meanwhile, surface soil, driven by runoff, enters shallow karst fissures (SKFs); these SKFs filled with soil have become the major habitat type in the area. Here, we explore the morphological characteristics of shallow karst fissures as well as the soil physical and chemical properties of the SKFs and comprehensively analyse the factors that influence the soil properties. Three key results are presented. First, a high heterogeneity of morphological characteristics exists for shallow karst fissures. According to the different characteristics of the vertical section, the SKFs can be divided into 5 types. These types are Rectangle-type, Pyramid-type, Funnel-type, Net-type and Diamond-type. In addition, the SKF dip angles were mainly between 60° and 90° (76.39%), the width of the top aperture was mainly between 20 and 40 cm (51.39%), and the trace lengths were mainly between 80 and 160 cm (76.39%). Second, compared with their characteristics of surface soil, the bulk density and fractal dimension of soil particles of the SKFs were both large, and the main composition of the SKF soil was clay. Third, the soil nutrients of the SKFs (the organic matter, total nitrogen and total phosphorus) were lower than the surface soil nutrients but not significantly so. The total potassium (TK) of the SKFs was greater than that observed for the surface and increased as the depth of the SKF increased. The soil nutrients of the SKFs were significantly affected by the fissure morphology. The poorly connected fissures had better soil fertility. When the morphological characteristics and soil properties of the SKFs were comprehensively considered, the vegetation types that were determined to be the best for use in the ecological restoration of areas of karst rocky desertification were deep-rooted plants with especially strong root penetration. The result of this study can supply some reference for future studies of karst rocky desertification control and vegetation restoration in the karst area of Southwest China; in the South Claw Silicon Island in Yogyakarta Province, Indonesia; and in other karst regions with the same ecological background.

Transport of polycyclic aromatic hydrocarbons in a highly vulnerable karst underground river system of southwest China.

The concentration and fluxes of polycyclic aromatic hydrocarbons (PAHs) were investigated in a karst underground river system in southwest China. Groundwater, particles, and sediments from underground river, topsoil, and surface water were monitored, allowing establishment of a conceptual model of PAH transport at the watershed scale. The results showed that PAHs could be transported from the surface to the subsurface through two migration pathways, which were slow-flowing water in the karst fissure and fast-flowing water in conduits. During rainfall events, increasing PAH levels (concentrations and fluxes) at the underground river exit indicated that hydrodynamic force could facilitate PAH transport. The PAHs in water were dominated by dissolved PAHs, accounting for 58.7% of total, especially in the freely dissolved phase, in which SPM-associated PAHs accounted for 41.3% of the total PAHs. Low molecular weight PAHs dominated transport and were mainly transported in dissolved form, whereas high molecular weight PAHs were dominated by SPM-associated transport during the rainfall events. A significantly positive correlation was observed between two-ring and three-ring freely dissolved PAHs and dissolved organic carbon (p < 0.01), respectively. Moreover, PAHs with four to five rings were relatively more abundant in the dissolved organic matter (DOM) associated phase than in the freely dissolved phase, suggesting a major role of DOM in their transport during rainfall events. The trend of PAH fluxes suggested that particle-facilitated transport was another dominant cause of PAH mobilization.

Mustelids (Carnivora, Mammalia) from Monte Tuttavista fissure fillings (Early and Middle Pleistocene; Orosei, Sardinia): Taxonomy and evolution of the insular Sardinian Galictini

The insular environment of Sardinia is renowned for its extensive palaeontological Palaeogene record, extending from the Eocene until recent times. In Sardinia, one of the most important localities for Quaternary faunas is the fillings of the karst fissures of the Monte Tuttavista site complex, which contain an impressive amount of fossil remains of around 70 vertebrate taxa. Several studies that have examined the network of the karst fissure cavities and their fossils have revealed some issues regarding the biochronological ordering, as well as some peculiarities in the recovered faunal associations (such as the presence of several carnivores). In this study, we analysed the record of the two large mustelids from this site, the genera Pannonictis and Enhydrictis. Our analyses point out several singular morphological and morphometric features of these taxa that suggest their attribution to two new species, Pannonictis baroniensis nov. sp. and Enhydrictis praegalictoides nov. sp. The proportions and the robust morphologies of P. baroniensis resemble those of other European taxa, such as P. pliocaenica, although other dentognatic and cranial features exclude a conspecific identity with previously known taxa. Conversely, E. praegalictoides represents the earliest member of the genus and shows a mixed pattern of derived features that are shared with the peculiar E. galictoides recovered from other Middle-Late Pleistocene Sardinian localities, as well as other more primitive characteristics that do not occur in this endemic mustelid. Considering the controversial debate regarding the evolutionary history of the tribe Galictini, the record of these new endemic species expands our knowledge of the systematics and the biogeography of the galictines and enriches the diversity of the tribe during the Early and Middle Pleistocene.

Discussion on Damages of Karst to Roadbed and Its Countermeasures

Because of the long-term dissolution of water, the formation of karst caves and fissures in rock formations are called karst. In Karst area, deformation and water damage are the main forms of karst damage to subgrade. Uneven settlement of embankment and instability of subgrade are the concrete manifestations of karst roadbed diseases. Therefore, considering the scale effect of karst, the concrete treatment measures of karst roadbed should be put forward and the principle of prevention and treatment of “dredging, crossing, reinforcing and blocking” should be followed, based on the characteristics of various karst forms, such as section funnel, depression, karst cave, solution crack and karst spring.

Relevance Between Hydrochemical and Hydrodynamic Data in a Deep Karstified Limestone Aquifer: a Mining Area Case Study

Safe coal mining in a karst region requires that mining operations assess any disturbances in the hydrogeological functioning of local aquifers and flow systems, and determine if disruptions are likely in the mine. We studied the geologic, hydraulic, and geochemical characteristics of the deep Ordovician karstified aquifer in the Xinglongzhuang and Dongtan mines of the Yanzhou coal mining district (China). The presence of a 100 m deep research borehole in the Ordovician limestone aquifer nearby facilitated hydrochemical and hydrodynamic data collection. The buried depth affected karst rock porosity, and the reduced porosity increased karst development. This, in turn, affected the abundance of water in the karst fissure. In addition to calcite and dolomite, the Ordovician limestone contains gypsum, which dissolves to form sulfate ions. Hydraulic data revealed that the water abundance in the research area is comparatively low, except for the C8 syncline zone. The Ordovician strata in this area is located in the deep, slow-flow zone of a vertical karst aquifer system, and the drilling unit water inflow is very low, which could represent the water abundance of the aquifer. Understanding this complex flow system is critical to appropriately assess the area’s deep groundwater resources and guide decision making regarding coal extraction.

A new species of Varanus (Anguimorpha: Varanidae) from the early Miocene of the Czech Republic, and its relationships and palaeoecology

Skeletal remains of a new early Miocene (Ottnangian, MN 4 mammal zone) monitor lizard, Varanus mokrensis sp. nov., are described from two karst fissures in the Mokrá-Western Quarry (1/2001 Turtle Joint; 2/2003 Reptile Joint), Czech Republic, providing the first documented example of a European varanid for which osteological data permit a well-supported assignment to the genus Varanus. The new species is morphologically similar to the Recent Indo-Asiatic varanids of the Varanus bengalensis group. It differs from all other Varanus species on the basis of a single autapomorphy and a combination of 11 characters. As a distinguishing feature of V. mokrensis, the parietal and squamosal processes of the postorbitofrontal form a narrowly acute angle. The teeth show distinct, smooth cutting edges along the mesial and distal margins of the apical portion of their crowns. This feature is not observed in most extant Asiatic Varanus species and may represent a plesiomorphic condition. The results of parsimony phylogenetic analyses, with and without character reweighting, reveal poor resolution within Varanus. A Bayesian analysis shows V. mokrensis to be closely related to extant representatives of the Indo-Asiatic Varanus clade, with close affinities to the V. bengalensis species group. The topology of the Bayesian tree supports the hypothesis that Miocene monitors from Mokrá are representatives of a lineage that is ancestral to the well-defined clade of extant African varanids, including the early Miocene V. rusingensis. In addition, our results support a Eurasian origin for the varanid clade. The extant African Varanus species probably originated in the late Oligocene. The radiation of African varanids probably occurred during the late Oligocene to early Miocene time interval. The occurrence of Varanus in the early Miocene of Mokrá-Western Quarry corresponds to the warm phase of the Miocene Climatic Optimum. Remains of a diverse aquatic and heliophobe amphibian fauna at the 2/2003 Reptile Joint site indicate more humid conditions than those at the 1/2001 Turtle Joint site.http://zoobank.org/urn:lsid:zoobank.org:pub:B1553295-8AC7-42F0-91C4-51C4C13F1C9D

Source Apportionment of Petroleum Hydrocarbon Contamination in Karst Fissure Groundwater

Based on 22 groundwater samples collected from the monitoring wells in the study area, 10 petroleum hydrocarbons concentration data are applied to statistical methods, which the principal component analysis followed by multivariate linear regression(PCA-MLR) was adopted to identify the possible sources and quantify the contributions of different pollution sources. Results showed that there existed three sources of pollution in the study area that are petroleum hydrocarbons pollution which derived from a refinery and an oil depot, chemical pollution which derived from a chemical plant, and machinery manufacturing pollution which derived from a mechanical factory. They contribute 68.26%, 10.11%, 21.63% to petroleum hydrocarbons pollution, respectively. Therefore, petroleum hydrocarbons pollution is the main source of groundwater pollution in the study area.

Application of comprehensive prediction method of water inrush hazards induced by unfavourable geological body in high risk karst tunnel: a case study

ABSTRACTWhile tunnelling in karst terrains, karst fissure water may endanger the safety of tunnel engineering and cause geological disasters such as water inrush. To ensure the safety of tunnel construction, in investigation stage, engineering geological and hydrogeological conditions of Jigongling Tunnel was analysed firstly. In design stage, a reasonable prediction method combining with optimization principle was selected to calculate the water inflow according to the geological and hydrogeological conditions analysed in the investigation stage. Then the advanced geological prediction was divided into different classes based on the water inflow. To make an accurate prediction, tunnel seismic prediction method, transient electromagnetic method, induced polarization method and advanced geological drilling were comprehensively applied in construction stage. This method combined with geology analysis, water inflow calculation and classification of advanced geological prediction is successfully applied in the Jigongling Tunnel of Fanba Expressway, and has provided a reference for the similar engineering constructions.

Novo najdišče pleistocenske sesalske favne v kamnolomu pri Črnem Kalu (Primorska, Slovenija) ter problematika zaščite in ohranjanja najdišč v kamnolomih

The Črni Kal quarry has been known for decades for fossils of Pleistocene mammal preserved in sinkholes or karst fissures fillings. We present some of the new fossil material discovered in the northern part of the quarry in 2016. The new site is an expanded karst fissure or cave filled with flowstone rubble and fine grained sediments with only one layer of bone breccia. The preliminary results of the analysis of fossil vertebrate remains show the presence of Merck's rhinoceros, currently unidentified species of deer and fragmented teeth of carnivores. Furthermore, we discuss some problems in documenting, protecting and preserving of Pleistocene fossil vertebrate sites in quarries in Slovenia.

The unique preservational environment of the Early Permian (Cisuralian) fossiliferous cave deposits of the Richards Spur locality, Oklahoma

The Richards Spur locality, Oklahoma, USA, represents an Early Permian infill in a series of Ordovician limestone and dolostone karst fissures. It exhibits the most diverse terrestrial Palaeozoic community currently known, with >40 distinct tetrapod taxa. Speleothems intimately associated with the site indicate that Richards Spur is a cave system, suggesting a preservational environment that is distinct from those of more typical Early Permian lowland deltaic/fluvial localities. Fossil material obtained from the caves is often found in disarticulation, although articulated material is not uncommon. This suggests that there were several factors that affected how animal remains became deposited within the caves. Many animals that died outside the caves were likely disarticulated on the surface and then washed in during rainfall events, resulting in mostly disarticulated remains. Alternatively, animals could be washed in before being disarticulated and some probably fell into the caves, resulting in less chance for their remains to become disarticulated. Supporting evidence for these preservational hypotheses comes in the form of wear caused by attritional processes. Disarticulated elements can exhibit high levels of wear, likely due to water transport that would carry them into the caves from the surface, as well as reworking within the caves. The partially and completely articulated remains are normally unworn, presumably due to a lesser degree of transport and reworking. X-ray diffraction and stable isotope analysis of cave infill further supports the interpretations made from fossil material. The results of this study provide a much-improved understanding of the preservational environment at Richards Spur, and will be useful in integrating information from this unique upland locality with that from the more extensively studied lowland localities of the Early Permian.

Study on Karst Features and its Influence on the Project of Wudongde Hydropower Station of Jinsha River

Wudongde canyon where the hydropower station will be built is deeply cut by the river with the height of more than 800m. Three type of rocks (sedimentary, metamorphic and volcanic rocks) outcrop at the project area. The complexity of the lithology of the Mesoproterozoic Huili Group Luoxue Formation (the limestone, marble, dolomite, marble lithification dolomite, quartzite and phyllite parallel to each other) combined with the complexity metamorphic process (including marble lithification, dolomization and sericitization) and the multiphase tectonic movement and multiphase transgressive period and regressive period formed the Wudongde canyon unique hydro-geological structures. The complexity of the geological conditions (complex lithology, tectonic structures, Neotectonics movement) combined with the dry-hot canyon meteorological conditions formed the complexity of the Wudongde caynon Karst features. The different karst types have developed such as the karst fissures, karst holes, horizontal caves and karst oblique caves. Based on the detailed geological data, the karst and hydro-geology features and the karst controlling factors have been systematically analyzed, meanwhile the karst influence on the project have been evaluated and the suggested measures have been taken to avoid the disadvantage conditions. The experience of Wudongde Hydropower station karst research can be as reference for other similar projects.

Provenance study of endokarst fine sediments through mineralogical and geochemical data (Lezetxiki II cave, northern Iberia)

The characteristics and provenance of the fine sediment forming the matrix of detrital endokarst fill can vary greatly, and their study provides valuable information about the paleoenvironment and the different sedimentary and diagenetic processes in which it was formed and deposited. This paper applies this study to the case of Lezetxiki II cave (Arrasate, Gipuzkoa). Using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM–EDS) analysis with samples of endokarst sediment, rocks and soils in the surroundings of the cave, the following source areas and sedimentary processes have been identified: 1) allochthonous sedimentation through the fluviokarst processes which eroded soils formed on siliciclastic formations. It is characterised by a high percentage of illite in the sediment and predominated in relatively cold periods in MIS 6 and MIS 2–4; 2) sedimentation through infiltration from karst fissures of the autochthonous soils formed on the limestone substrate (terra rossa). It is characterised by a higher vermiculite content, and prevailed in the warm MIS 5 period and the Holocene; 3) chemical sedimentation, where calcite precipitated in the form of speleothems in warmer and more humid periods; and 4) deposition of microfauna bones in owl pellets.

Discussion on Treatment Technology of Reinforcement Pile in Karst Area

With the example of pile foundation engineering in the limestone karst fissure reinforcement, discusses the principle of reinforcement of pile foundation in karst area, introduces some construction technology of pile foundation reinforcement, the reinforcement design principles and the reinforcement scheme is briefly discussed, and combined with the engineering practice and put forward a set of safety, economy and reasonable treatment plan, to reinforcement technology promote the karst pile foundation bottom cave, fracture.

Numerical Simulation of Seepage Field in Aquifer under the Coal Seam

In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.

基于修正RISKE模型的重庆岩溶地区地下水脆弱性评价

Assessment of karst groundwater vulnerability provides an efficient means for protection,management and utilization of karst groundwater resources. Groundwater tends to be polluted due to the lack of protection zoning in place over most karst area in southwest China. This paper reviews and adapts the RISKE model for a use in assessing the karst groundwater vulnerability in Chongqing. It is concluded that the distribution of karst areas in a decreasing order is identified as the Northeast( 43.14%) 、the Southeast( 42. 82%) 、the east( 9. 82%) and the west of Chongqing( 4. 22%),while the areas exceeding the medium vulnerability threshold are the Southeast( 33. 29%) 、the Northeast( 29. 21%) 、the east( 6. 68%) and the west( 2.37%) in Chongqing. In terms of the groundwater quality,ranks from the worst to the best are the Southeast、the Northeast、the west and the east of Chongqing,respectively. It is further concluded that the spatial characteristics of the groundwater vulnerability in the areas is affected not only by the natural characteristics such as lithology、soil、sinkholes、karst fissure etc,but also by human activities. It is realistic that the control of human activitiesshould be prioritized in order to mitigate groundwater pollution.

Ursidae (Mammalia, Carnivora) from the Late Oligocene of the “Phosphorites du Quercy” (France) and a reappraisal of the genusCephalogaleGeoffroy, 1862

ABSTRACT Many karstic fissure fillings from the Quercy (France) constitute fossil bearing localities which give an exceptional open laboratory for the study of evolution of vertebrates and especially mammals from the Eocene to the Early Miocene. A couple of localities from the Late Oligocene (MP 28 = 24.9-24.5 Ma) have yielded, among several taxa, the best sample ever found of a hemicyonine ursid. This sample corresponds to a new species and allows a reappraisal of several other species belonging to lineages attributed to a new tribe (Cephalogalini n. tr.). The latter occupied in Europe along the Oligocene and the lower Miocene some canid-like ecological niches. This tribe was replaced at the end of the Lower Miocene by the Hemicyonini, another tribe of Hemicyoninae (Ursidae).

Hoplitomerycidae (Ruminantia; Late Miocene, Central-Southeastern Italy): Whom and where from?

The endemic monogeneric fossil family Hoplitomerycidae currently includes six known species, the remains of which are found in Lower Tortonian coastal tidal-flat layered calcarenites at Scontrone, in Abruzzo (central Italy), as well as in karstic fissure fillings, supposedly of Messinian age, in the Gargano Promontory, Apulia (southeastern Italy). Their remains are found associated with bones of many other vertebrates which indicate the existence of a vast territory, the so-called Abruzzo-Apulia Platform, which was isolated from the nearest mainland at least from the Early Oligocene up to the latest Miocene. A recent cladistic analysis showed that the classification of the hoplitomerycids in Cervoidea, which currently enjoys vast popularity, is not justified. The family is characterized by a set of cranial and postcranial primitive traits, above all their non-parallel-sided astragalus, that suggest that the family probably stemmed from a primitive ruminant stock somewhere before the emergence of Pecora, consistent with geological evidence showing that about 29Ma a land-bridge connected the Abruzzo-Apulia Platform with the Balkans across the Adriatic Sea, approximately where the Tremiti islands are today. The present study intended to reconnect to the results of the cladistic analysis and to extend them in the attempt to track down the possible ancestors of Hoplitomerycidae. The family expectedly radiated developing autapomorphic features that make the search quite arduous. Nonetheless, its primitive, leftover characters relate it to Oligocene basal ruminants with asymmetric astragalus. Following the distribution of the non-parallel astragalus through space and time leads to speculate a possible origin of the family from primitive Tragulina representatives that dispersed in Anatolia in the course of the Oligocene. Current reconstructions of the Early Oligocene paleogeography of the eastern Mediterranean show that the Apulian Platform was connected via a cross-Adriatic land-bridge to the Balkans, Anatolia and by that way also to middle and central Asia and central-eastern Europe.

Application Analysis of Comprehensive Advanced Geological Prediction in Karst Tunnel

Based on the DaDu mountain tunnel of new construction ShangHai-KunMing high-speed railway, combine with field geology investigation of the tunnel address area comparative analysis TRT advanced geological prediction, infrared probe water, ground penetrating radar advance geological forecasting and tunnel design data, aimed at fault fracture zone, high-pressure water-rich belt, the karst fissures developmental situation may have in construction period of DaDu mountain tunnel, carried out the comprehensive advanced geological prediction and then combined with the actual excavation situation contrast and verify the feasibility and practicality of the comprehensive geological advanced prediction technology, and it will have important significance of reference for the similar tunnel project in design and construction period.

Late Miocene Sciuridae (Mammalia, Rodentia) from Anatolia, Turkey

ABSTRACT Isolated cheek teeth of Sciuridae (Rodentia, Mammalia) from nine late Miocene localities in central Anatolia (Turkey) are described. The teeth represent at least 12 different species, five of which belong to the ground squirrel genus Tamias, two to the ground squirrel genus Spermophilinus, one to the flying squirrel genus Hylopetes, and two to the flying squirrel genus Pliopetaurista. One species, Tamias anatoliensis (type locality Altıntaş 1), is new. An unknown genus and species of giant tree or ground squirrel is represented by one tooth. Two teeth probably form the oldest record in western Eurasia of the tree squirrel genus Sciurus. Seven of the localities that yielded Sciuridae are lacustrine deposits, two are karst fissure fills. Their estimated ages range from MN 9 to MN 13. The majority of late Miocene Sciuridae from Anatolia show affinities with European sciurids of the same period.