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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

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That stream profile is the elevation of the main stream bed as a function of distance from outflow.?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for fracture networks (Keyword) returned 14 results for the whole karstbase:
Modeling of regional groundwater flow in fractured rock aquifers, PhD Thesis, 1990, Kraemer, S. R.

The regional movement of shallow groundwater in the fractured rock aquifer is examined through a conceptual-deterministic modeling approach. The computer program FRACNET represents the fracture zones as straight laminar flow conductors in connection to regional constant head boundaries within an impermeable rock matrix. Regional scale fracture zones are projected onto the horizontal plane, invoking the Dupuit-Forchheimer assumption for flow. The steady state flow solution for the two dimensional case is achieved by requiring nodal flow balances using a Gauss-Seidel iteration. Computer experiments based on statistically generated fracture networks demonstrate the emergence of preferred flow paths due to connectivity of fractures to sources or sinks of water, even in networks of uniformly distributed fractures of constant length and aperture. The implication is that discrete flow, often associated with the local scale, may maintain itself even at a regional scale. The distribution of uniform areal recharge is computed using the Analytic Element Method, and then coupled to the network flow solver to complete the regional water balance. The areal recharge weakens the development of preferential flow pathways. The possible replacement of a discrete fracture network by an equivalent porous medium is also investigated. A Mohr's circle analysis is presented to characterize the tensor relationship between the discharge vector and the piezometric gradient vector, even at scales below the representative elementary volume (REV). A consistent permeability tensor is sought in order to establish the REV scale and justify replacement of the discrete fracture network by an equivalent porous medium. Finally, hydrological factors influencing the chemical dissolution and initiation of conduits in carbonate (karst) terrain are examined. Based on hydrological considerations, and given the appropriate geochemical and hydrogeological conditions, the preferred flow paths are expected to develop with time into caves.


Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records, 1994, Riggs Alan C. , Carr W. J. , Kolesar Peter T. , Hoffman Ray J. ,
Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation

Structure, flow, and generalized conductivity scaling in fracture networks, 1999, Margolin G. , Berkowitz B. , Scher H.

We present a three-dimensional (3-D) model of fractures that within the same framework, allows a systematic study of the interplay and relative importance of the two key factors determining the character of flow in the system. The two factors of complexity are () the geometry of fracture plane structure and interconnections and (2) the aperture variability within these planes. Previous models have concentrated on each separately. We introduce anisotropic percolation to model a wide range of fracture structures and networks. The conclusion is that either of these elements, fracture geometry and aperture variability, can give rise to channeled flow and that the interplay between them is especially important for this type of flow. Significant outcomes of our study are (1) a functional relationship that quantifies the dependence of the effective hydraulic conductivity on aperture variability and on the network structure and fracture element density, (2) a relation between aperture variability and the Peclet number, and (3) a basis for a new explanation for the field-length dependence of permeability observed in fractured and heterogeneous porous formations.


Mechanical stratigraphic controls on fracture patterns within carbonates and implications for groundwater flow, 2006, Cooke Ml, Simo Ja, Underwood Ca, Rijken P,
Groundwater flow in low matrix-permeability carbonate rocks is largely controlled by fracture networks. The stratigraphic features that control fracture initiation and termination within a sequence of sedimentary rock strata define the mechanical stratigraphy of the sequence. We investigate the effectiveness of various types of stratigraphic horizons in terminating opening-mode fractures in two different carbonate rock sequences: a relatively homogeneous dolomite sequence, in Door County, WI and an interbedded chalk and marl sequence within the Austin Chalk, TX. Additionally, we present analog and numerical modeling results that delineate the specific mechanisms that facilitate fracture termination. The combination of model results and empirical relationships between observed sedimentary features and mechanical stratigraphy shows: (1) fractures terminate at weak contacts (e.g. thin organic layers), shallowly buried contacts or thick fine-grained units adjacent to thin fractured beds, (2) fractures propagate across strong contacts (e.g. intracycle contacts between different lithology) and thin fine-grained units adjacent to thick fractured beds and (3) fractures step-over at moderate strength contacts. We use these guidelines to predict fracture network from sedimentary stratigraphy by qualitatively assessing the mechanical stratigraphy of a portion of the relatively complex Cretaceous shelf-margin sequence at Sant Corneli, Spain. This predictive demonstration illustrates the utility of assessing the mechanical stratigraphy of subsurface strata within which fractures are not directly observable. We conclude that for a variety of carbonate mechanical stratigraphic sequences, dominant fluid flow characteristics, such as horizontal high flow zones and flow compartmentalization, can be evaluated using fracture spacing and connectivity within fracture networks that is predicted from sedimentary stratigraphy. Although the resulting heterogeneous flow networks do not rely on every fracture present, they are highly dependent on the mechanical stratigraphy

Seasonal variations of CO2 and 222Rn in a Mediterranean sinkhole-spring (Causse dAumelas, SE France)., 2007, Batiotguilhe Christelle, Seidel Jeanluc, Jourde Herv, Hbrard Olivier, Baillycomte Vincent
Carbon dioxide and 222Rn monitoring of the atmosphere of a Mediterranean sink hole - spring (SE France) during two hydrological cycles (from September 2004 to September 2006) showed seasonal variations with very high concentrations during summer (greater than 6% and 20000 Bq/m3, respectively). Gas dynamics in caves often show seasonal variations. Meteorological parameters (barometric pressure and temperature mainly), cave geometry and fracture networks control exchanges between the cavity and outside atmosphere. Carbon dioxide and 222Rn may have different sources (atmosphere, soil, bedrock, deep gas diffusion, in situ oxidation of organic matter and, in some caves, the key role of swift underground streams). For a CO2 origin, 13C measurements on water and gas samples taken into the cavity suggest a superficial origin. Radon-222 appears to be locally produced and transported by biogenic CO2. Further investigations will be carried out in order to study the relationship of gas-level variations with barometric pressure variations and piezometric level fluctuations within the aquifer.

Seasonal variations of CO2 and 222Rn in a Mediterranean sinkhole-spring (Causse dAumelas, SE France), 2007, Batiotguilhe Christelle, Seidel Jeanluc, Jourde Herv, Hbrard Olivier, Baillycomte Vincent
Carbon dioxide and 222Rn monitoring of the atmosphere of a Mediterranean sink hole - spring (SE France) during two hydrological cycles (from September 2004 to September 2006) showed seasonal variations with very high concentrations during summer (greater than 6% and 20 000 Bq/m3, respectively). Gas dynamics in caves often show seasonal variations. Meteorological parameters (barometric pressure and temperature mainly), cave geometry and fracture networks control exchanges between the cavity and outside atmosphere. Carbon dioxide and 222Rn may have different sources (atmosphere, soil, bedrock, deep gas diffusion, in situ oxidation of organic matter and, in some caves, the key role of swift underground streams). For a CO2 origin, 13C measurements on water and gas samples taken into the cavity suggest a superficial origin. Radon-222 appears to be locally produced and transported by biogenic CO2. Further investigations will be carried out in order to study the relationship of gas-level variations with barometric pressure variations and piezometric level fluctuations within the aquifer.

Karst and Early Fracture Networks in Carbonates, Turks and Caicos Islands, British West Indies, 2007, Guidry Sean A. , Grasmueck Mark, Carpenter Daniel G. , Gombos Andrew M. Jr. , Bachtel Steven L. , Viggiano David A. ,
Historically, studies of Quaternary carbonates have not adequately addressed the influence of early fracture networks on diagenesis. Because of this lack of detail, understanding and predicting fracture-related diagenetic heterogeneities and preferential fluid flow pathways in ancient carbonate successions is particularly challenging. The Pleistocene oolitic grainstones of the Caicos platform provide an excellent opportunity to evaluate the relative importance of fractures on early diagenetic alteration styles, and are a suitable analog for subsurface carbonate reservoirs. Detailed analyses of fractures (e.g., orientation, aperture, spacing, fill material) from Caicos outcrops combined with high-resolution, three-dimensional ground-penetrating radar (3D GPR), assisted in exploring the causality and distribution of fractures and relationship to karst. Four models were evaluated to explain the observed distribution of dolines: (1) gravitational, fractured-margin controlled, (2) tectonic-fracture controlled, (3) antecedent-topography controlled, and (4) a hybrid model. Based on observations of numerous fractures (n = 306) on the western Caicos platform, early fractures are abundant and dominantly margin-parallel. These fracture networks are well established in limestones prior to mineralogical stabilization, thereby indicating that diagenetic heterogeneities evolve very early in carbonate diagenesis. The spatial distribution of dolines on Providenciales is likely the result of a complex interplay between the antecedent topography, margin-parallel fracture systems, and meteoric fluids. Resultant diagenetic alteration is far more complicated than simple, unconfined, meteoric lenses associated with topographic highs. Any attempts to model early diagenesis in carbonates should not dismiss the role of fractures as diagenetic facilitators and diagenetic anisotropy templates

Fractal analysis of the distribution of cave lengths in Slovenia, 2007, Verbovš, Ek T.

The lengths of the Slovenian caves follow the power-law distribution through several orders of magnitude, which implies that the caves can be considered as natural fractal objects. Fractal dimensions obtained from distribution of all caves are about 1.07, and vary within different tectonic and hydrogeological units. Some deviations from the ideal best fit line in log-log plots (i.e. lower and upper cut-off limits) can be explained by underestimation, as many very short caves are not registered. The study of tectonic and hydrogeological setting indicates that the greatest dimensions occur in the rocks with karstic-fracture and fracture porosity and the lowest in low-permeability rocks. Proximity to major tectonic structures shows a detectable effect on the cave length distribution, and the influence is greatest for the caves closer to the faults and thrust fronts. Dimensions are lower than those of fracture networks and faults, which can be most probably explained by flow channeling along the fracture networks, which causes the decrease of fractal dimension. The physical causes of power law scaling and variations in fractal dimensions (power law exponents) are still poorly understood, but the behaviour of fracture networks is believed to be caused by a scale-independent fractal fragmentation of the blocks, and during the process of forming the caves inherit some fractal geometrical properties of the networks.


Structurally complex reservoirs: an introduction, 2007, Jolley S. J. , Barr D. , Walsh J. J. , Knipe R. J.

Structurally complex reservoirs form a distinct class of reservoir, in which fault arrays  and fracture networks, in particular, exert an over-riding control on petroleum trapping and production  behaviour. With modern exploration and production portfolios commonly held in geologically  complex settings, there is an increasing technical challenge to find new prospects and to  extract remaining hydrocarbons from these more structurally complex reservoirs. Improved  analytical and modelling techniques will enhance our ability to locate connected hydrocarbon  volumes and unswept sections of reservoir, and thus help optimize field development, production  rates and ultimate recovery. This volume reviews our current understanding and ability to model the  complex distribution and behaviour of fault and fracture networks, highlighting their fluid compartmentalizing  effects and storage-transmissivity characteristics, and outlining approaches for predicting  the dynamic fluid flow and geomechanical behaviour of structurally complex reservoirs.  This introductory paper provides an overview of the research status on structurally complex reservoirs  and aims to create a context for the collection of papers presented in this volume and, in doing  so, an entry point for the reader into the subject. We have focused on the recent progress and outstanding  issues in the areas of: (i) structural complexity and fault geometry; (ii) the detection and  prediction of faults and fractures; (iii) the compartmentalizing effects of fault systems and complex  siliciclastic reservoirs; and (iv) the critical controls that affect fractured reservoirs.


Hypogene Speleogenesis and Karst Hydrogeology of Artesian Basins, 2009,

The volume contains papers presented during the International Conference held May 13 through 17, 2009 in Chernivtsi, Ukraine.

The PDF file contains cover, title and contents pages. Download and save this file to your disk and use hyperlinked titles of papers in the content list to download PDF files of individual papers. 

CONTENTS

PRINCIPAL FEATURES OF HYPOGENE SPELEOGENESIS
Alexander Klimchouk

HYPOGENE CAVE PATTERNS
Philippe Audra, Ludovic Mocochain, Jean-Yves Bigot, and Jean-Claude Nobécourt

MORPHOLOGICAL INDICATORS OF SPELEOGENESIS: HYPOGENIC SPELEOGENS
Philippe Audra, Ludovic Mocochain, Jean-Yves Bigot, and Jean-Claude Nobécourt

HYPOGENE CAVES IN DEFORMED (FOLD BELT) STRATA: OBSERVATIONS FROM EASTERN AUSTRALIA AND CENTRAL EUROPE
R.A.L. Osborne

IDENTIFYING PALEO WATER-ROCK INTERACTION DURING HYDROTHERMAL KARSTIFICATION: A STABLE ISOTOPE APPROACH
Yuri Dublyansky and Christoph Spötl

MICROORGANISMS AS SPELEOGENETIC AGENTS: GEOCHEMICAL DIVERSITY BUT GEOMICROBIAL UNITY
P.J.Boston, M.N. Spilde, D.E. Northup, M.D. Curry, L.A. Melim, and L. Rosales-Lagarde

SIDERITE WEATHERING AS A REACTION CAUSING HYPOGENE SPELEOGENESIS: THE EXAMPLE OF THE IBERG/HARZ/GERMANY Stephan Kempe

SIMULATING THE DEVELOPMENT OF SOLUTION CONDUITS IN HYPOGENE SETTINGS
C. Rehrl, S. Birk, and A.B. Klimchouk

EVOLUTION OF CAVES IN POROUS LIMESTONE BY MIXING CORROSION: A MODEL APPROACH
Wolfgang Dreybrodt, Douchko Romanov, and Georg Kaufmann

SPELEOGENESIS OF MEDITERRANEAN KARSTS: A MODELLING APPROACH BASED ON REALISTIC FRACTURE NETWORKS
Antoine Lafare, Hervé Jourde, Véronique Leonardi, Séverin Pistre, and Nathalie Dörfliger

GIANT COLLAPSE STRUCTURES FORMED BY HYPOGENIC KARSTIFICATION: THE OBRUKS OF THE CENTRAL ANATOLIA, TURKEY
C. Serdar Bayari, N. Nur Ozyurt, and Emrah Pekkans

ON THE ROLE OF HYPOGENE SPELEOGENESIS IN SHAPING THE COASTAL ENDOKARST OF SOUTHERN MALLORCA (WESTERN MEDITERRANEAN)
Joaquín Ginés, Angel Ginés, Joan J. Fornós, Antoni Merino and Francesc Gràcia

HYPOGENE CAVES IN THE APENNINES (ITALY)
Sandro Galdenzi

STEGBACHGRABEN, A MINERALIZED HYPOGENE CAVE IN THE GROSSARL VALLEY, AUSTRIA
Yuri Dublyansky, Christoph Spötl, and Christoph Steinbauer

HYPOGENE CAVES IN AUSTRIA
Lukas Plan, Christoph Spötl, Rudolf Pavuza, Yuri Dublyansky

KRAUSHÖHLE: THE FIRST SULPHURIC ACID CAVE IN THE EASTERN ALPS (STYRIA, AUSTRIA) (Abstract only)
Lukas Plan, Jo De Waele, Philippe Audra, Antonio Rossi, and Christoph Spötl

HYDROTHERMAL ORIGIN OF ZADLAŠKA JAMA, AN ANCIENT ALPINE CAVE IN THE JULIAN ALPS, SLOVENIA
Martin Knez and Tadej Slabe

ACTIVE HYPOGENE SPELEOGENESIS AND THE GROUNDWATER SYSTEMS AROUND THE EDGES OF ANTICLINAL RIDGES
Amos Frumkin

SEISMIC-SAG STRUCTURAL SYSTEMS IN TERTIARY CARBONATE ROCKS BENEATH SOUTHEASTERN FLORIDA, USA: EVIDENCE FOR HYPOGENIC SPELEOGENESIS?
Kevin J. Cunningham and Cameron Walker

HYPOGENE SPELEOGENESIS IN THE PIEDMONT CRIMEA RANGE
A.B. Klimchouk, E.I. Tymokhina and G.N. Amelichev

STYLES OF HYPOGENE CAVE DEVELOPMENT IN ANCIENT CARBONATE AREAS OVERLYING NON-PERMEABLE ROCKS IN BRAZIL AND THE INFLUENCE OF COMPETING MECHANISMS AND LATER MODIFYING PROCESSES
Augusto S. Auler

MORPHOLOGY AND GENESIS OF THE MAIN ORE BODY AT NANISIVIK ZINC/LEAD MINE, BAFFIN ISLAND, CANADA: AN OUTSTANDING EXAMPLE OF PARAGENETIC DISSOLUTION OF CARBONATE BEDROCKS WITH PENE-CONTEMPORANEOUS PRECIPITATION OF SULFIDES AND GANGUE MINERALS IN A HYPOGENE SETTING
Derek Ford

THE INFLUENCE OF HYPOGENE AND EPIGENE SPELEOGENESIS IN THE EVOLUTION OF THE VAZANTE KARST MINAS GERAIS STATE, BRAZIL
Cristian Bittencourt, Augusto Sarreiro Auler, José Manoel dos Reis Neto, Vanio de Bessa and Marcus Vinícios Andrade Silva

HYPOGENIC ASCENDING SPELEOGENESIS IN THE KRAKÓW-CZĘSTOCHOWA UPLAND (POLAND) ? EVIDENCE IN CAVE MORPHOLOGY AND SURFACE RELIEF
Andrzej Tyc

EVIDENCE FROM CERNA VALLEY CAVES (SW ROMANIA) FOR SULFURIC ACID SPELEOGENESIS: A MINERALOGICAL AND STABLE ISOTOPE STUDY
Bogdan P. Onac, Jonathan Sumrall, Jonathan Wynn, Tudor Tamas, Veronica Dărmiceanu and Cristina Cizmaş

THE POSSIBILITY OF REVERSE FLOW PIRACY IN CAVES OF THE APPALACHIAN MOUNTAIN BELT (Abstract only)
Ira D. Sasowsky

KARSTOGENESIS AT THE PRUT RIVER VALLEY (WESTERN UKRAINE, PRUT AREA)
Viacheslav Andreychouk and Bogdan Ridush

ZOLOUSHKA CAVE: HYPOGENE SPELEOGENESIS OR REVERSE WATER THROUGHFLOW?
V. Eirzhyk (Abstract only)

EPIGENE AND HYPOGENE CAVES IN THE NEOGENE GYPSUM OF THE PONIDZIE AREA (NIECKA NIDZIAŃSKA REGION), POLAND
Jan Urban, Viacheslav Andreychouk, and Andrzej Kasza

PETRALONA CAVE: MORPHOLOGICAL ANALYSIS AND A NEW PERSPECTIVE ON ITS SPELEOGENESIS
Georgios Lazaridis

HYPOGENE SPELEOGENESIS IN MAINLAND NORWAY AND SVALBARD?
Stein-Erik Lauritzen

VILLA LUZ PARK CAVES: SPELEOGENESIS BASED ON CURRENT STRATIGRAPHIC AND MORPHOLOGIC EVIDENCE (Abstract only)
Laura Rosales-Lagarde, Penelope J. Boston, Andrew Campbell, and Mike Pullin

HYPOGENE KARSTIFICATION IN SAUDI ARABIA (LAYLA LAKE SINKHOLES, AIN HEETH CAVE)
Stephan Kempe, Heiko Dirks, and Ingo Bauer

HYPOGENE KARSTIFICATION IN JORDAN (BERGISH/AL-DAHER CAVE, UWAIYED CAVE, BEER AL-MALABEH SINKHOLE)
Stephan Kempe, Ahmad Al-Malabeh, and Horst-Volker Henschel

ASSESSING THE RELIABILITY OF 2D RESISTIVITY IMAGING TO MAP A DEEP AQUIFER IN CARBONATE ROCKS IN THE IRAQI KURDISTAN REGION
Bakhtiar K. Aziz and Ezzaden N. Baban

FEATURES OF GEOLOGICAL CONDITIONS OF THE ORDINSKAYA UNDERWATER CAVE, FORE-URALS, RUSSIA
Pavel Sivinskih

INIAAIIINOE AEIIAAIIIAI NIAEAIAAIACA AI?II-NEEAA?AOIE IAEANOE CAIAAIIAI EAAEACA
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AEOAEIIIA NO?IAIEA AEA?IAAINOA?U: IIAAEU AA?OEEAEUIIE CIIAEUIINOE
A.I. Eaoaaa

?IEU EA?NOA A OI?IE?IAAIEE NIEAIUO AIA E ?ANNIEIA IEAI?ENEIAI AANNAEIA
Aeaenaia? Eiiiiia, Na?aae Aeaenaaa, e Na?aae Nooia


SPELEOGENESIS OF MEDITERRANEAN KARSTS: A MODELLING APPROACH BASED ON REALISTIC FRACTURE NETWORKS, 2009, Lafare A. , Jourde H. , Leonardi V. , Pistre S. , Dorfliger N.

There are several numerical modelling approaches of speleogenesis in existence today. They take into account physical and chemical laws for flow and dissolution in fractured carbonate aquifers. Nevertheless, the initial void networks considered by these models generally do not correspond to the fracturing reality. The approach proposed here aims to simulate speleogenesis in an aquifer characterized by a fracture network, while matching field reality as closely as possible and respecting geometrical properties. Using statistical and geometrical parameters obtained by field observations and analogue experiments, it is possible to generate 3-D realistic networks in terms of the relative position of joints that control the overall network connectivity. Once the fracture networks are generated, they are adapted and incorporated in a 3-D ground water flow and transport finite element model. The flow simulations in the fracture networks allow determination of the spatial distribution of flow velocities for the initial configuration. This distribution, added to other information such as age and travel time, is used to simulate the evolution of the apertures of the different elements. This paper mainly presents the theoretical basis for the proposed method, from the fracturing model to the incorporation of the generated network in the flow model. Then, it describes the principles leading to forthcoming first benchmark simulations which will be used to develop the analogical rules concerning karst aquifer evolution, and for lead sensibility analysis.


Controls on paleokarst heterogeneity. Integrated study of the Upper Permian syngenetic karst in Rattlesnake Canyon, Guadalupe Mountains, USA, 2011, Labraa De Miguel, Gemma

The present study contributes to a better understanding of early dissolution mechanisms for syngenetic karst development and provides constraints on the timing of formation of the Rattlesnake Canyon paleokarst system in the Guadalupe Mountains, New Mexico, U.S.A. Paleozoic paleokarsts commonly undergo burial and collapse, which reduces significantly the preservation of early fracture networks and geometries of dissolution. Rattlesnake Canyon constitutes a magnificent scenario for the study of global controls on Upper Permian karsting since early fracture networks and dissolution geometries are extremely well preserved and lack major tectonic deformation. This thesis sheds light on the scientific knowledge of paleokarsts and can be of interest to the oil industry since paleokarsts are common targets of exploration. As the evolution of the reservoir properties is often diagenetically controlled, the diagenetic study was particularly useful in determining the degree of sealing following hydrocarbon charge. 1) Aims This thesis seeks to improve our understanding of the relationship between early syndepositional fracture networks that are typically found in platform margins and syngenetic karst development. The thesis includes multidisciplinary carbonate studies aimed at understanding the multiscale paleokarst heterogeneity by means of (i) the development of a conceptual model for the karst evolution, (ii) the construction of a 3D paleokarst model, (iii) the determination of the diagenetic history of the paleokarst system and (iv) the paleokarst reservoir characterization. 2) Thesis Structure The thesis consists of 9 chapters and 2 appendices. Chapter 1 sets out the rationale for this thesis. Chapter 2 provides an introduction to the most basic aspects of karst science and to the hydrogeological model of Carbonate Island as well as an overview of the state-of-the-art paleokarst studies. The geological setting and the study area is detailed in Chapter 3. The results of the thesis are contained in Chapters 4 to 7. Because of the multidisciplinary nature of this thesis, each of these chapters is dedicated to one discipline. Chapter 4 focuses on the analysis of field data to obtain a conceptual model for the evolution of the paleokarst system. Chapter 5 discusses the methodology to implement the 3D paleokarst model and provides data to assess the dimensions of the system in subsurface. Chapter 6 focuses on the diagenetic stages that affected and controlled the karst development. Finally, Chapter 6 offers a paleokarst reservoir characterization. A comprehensive approach and discussion of the results obtained in each of these chapters are included in Chapter 8. General and specific conclusions are presented in Chapter 9. Appendix One contains a representative image compendium of the petrographic features observed in the paleokarst filling sequence of Fault N. Appendix Two sets out the raw data from the geochemical analysis. The paleokarst analysis using different disciplines provides a complete characterization of paleokarst heterogeneity and enables us to elucidate the controls of the system.


Springs, 2012, White, William B.

Springs are localized points where groundwater returns to surface routes. Karst springs drains integrated conduit and fracture networks and often have very high discharges. Most spring waters have temperatures very close to local seasonal averages but some waters rise from depths and produce thermal springs. Spring discharges tend to respond rapidly to storm recharge. The hydrographs of springs can be analyzed to provide information on the conduit system that feeds the spring. Karst springs are highly vulnerable to contamination from surface sources. Great caution must be exercised before using karst springs as water supplies.


Effective porosity of a carbonate aquifer with bacterial contamination: Walkerton, Ontario, Canada, 2012, Worthington S. R. H. , Smart C. C. , Ruland W.

Preferential flow through solutionally enlarged fractures can be a significant influence on travel times and source area definition in carbonate aquifers. However, it has proven challenging to step beyond a conceptual model to implementing, parameterizing and testing an appropriate numerical model of preferential flow. Here both porous medium and preferential flow models are developed with respect to a deadly contamination of the municipal groundwater supply at Walkerton, Ontario, Canada. The preferential flow model is based on simple orthogonal fracture aperture and spacing. The models are parameterized from bore hole, gamma, flow and video logs resulting in a two order of magnitude lower effective porosity for the preferential flow model. The observed hydraulic conductivity and effective porosity are used to predict groundwater travel times using a porous medium model. These model predictions are compared to a number of independent estimates of effective porosity, including three forced gradient tracer tests. The results show that the effective porosity and hydraulic conductivity values closely match the preferential flow predictions for an equivalent fracture network of _10 m spacing of 1 mm fractures. Three tracer tests resulted in groundwater velocities of hundreds of meters per day, as predicted when an effective porosity of 0.05% was used in the groundwater model. These velocities are consistent with a compilation of 185 tracer test velocities from regional Paleozoic carbonate aquifers. The implication is that carbonate aquifers in southern Ontario are characterized by relatively low-volume dissolutionally enlarged fracture networks that dominate flow and transport. The porous matrix has large storage capacity, but contributes little to transport. Numerical models based on much higher porosities risk significantly underestimating capture zones in such aquifers. The hydraulic conductivity – effective porosity prediction framework provides a general analytical frame work for a preferential flow carbonate aquifer. Not only is the framework readily parameterized from borehole observations, but also it can be implemented in a conventional porous medium model, and critically tested using simple tracer tests.


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