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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 equivalent per million is the number of equivalent weights in a million parts per weight solution [16].?

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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 simulations (Keyword) returned 72 results for the whole karstbase:
Showing 46 to 60 of 72
EXAMINING A COUPLED CONTINUUM PIPE-FLOW MODEL FOR GROUNDWATER FLOW AND SOLUTE TRANSPORT IN A KARST AQUIFER, 2010, Hu B. X.
A coupled continuum pipe-flow (CCPF) model has been developed for groundwater flow and solute transport in a karst aquifer with conduits. Groundwater flow in conduits is simulated through a pipe flow model and flow in fissured matrix rock is described by Darcys law. Water mass exchange between the two domains is modeled by a firstorder exchange rate method. In this study, we investigate mathematical well-posedness (mathematical term, which means solution existence and uniqueness) of the CCPF model, develop a finite elementary method to numerically approximate the mathematical model and study the convergence of the numerical method. The study results prove the modeling approach is mathematically well posed and numerically converged. To study the accuracy of the CCPF model, a recently developed Stokes-Darcy (SD) model and CCPF model are compared with laboratory experimental results. It was found that the SD model simulations match well with experimental results, but the CCPF model overestimates the hydraulic head in the matrix, especially around the matrix and conduit interface. The model underestimates solute transport in the conduit and does not capture the plume distribution in the matrix. In comparison with the SD model, the CCPF model requires an additional parameter, the first-order mass exchange rate, and the parameter is normally obtained through inverse method curve fitting. The SD method may provide an approach to directly estimate the parameter value.

The initial stages of cave formation: Beyond the one-dimensional paradigm, 2011, Szymczak Piotr, Ladd Anthony J. C.

The solutional origin of limestone caves was recognized over a century ago, but the short penetration length of an undersaturated solution made it seem impossible for long conduits to develop. This is contradicted by field observations, where extended conduits, sometimes several kilometers long, are found in karst environments. However, a sharp drop in the dissolution rate of CaCO3 near saturation provides a mechanism for much deeper penetration of reactant. The notion of a “kinetic trigger” – a sudden change in rate constant over a narrow concentration range – has become a widely accepted paradigm in speleogenesis modeling. However, it is based on one-dimensional models for the fluid and solute transport inside the fracture, assuming that the dissolution front is planar in the direction perpendicular to the flow. Here we show that this assumption is incorrect; a planar dissolution front in an entirely uniform fracture is unstable to infinitesimal perturbations and inevitably breaks up into highly localized regions of dissolution. This provides an alternative mechanism for cave formation, even in the absence of a kinetic trigger. Our results suggest that there is an inherent wavelength to the erosion pattern in dissolving fractures, which depends on the reaction rate and flow rate, but is independent of the initial roughness. In contrast to one-dimensional models, two-dimensional simulations indicate that there is only a weak dependence of the breakthrough time on kinetic order; localization of the flow tends to keep the undersaturation in the dissolution front above the threshold for non-linear kinetics.

Research Highlights
- A kinetic trigger is not a prerequisite for limestone cave formation. - The added spatial dimension has a larger impact on breakthrough times than a kinetic trigger. - Planar dissolution front in a fracture is unstable to infinitesimal perturbations. - The most unstable wavelength depends on reaction kinetics and flow rate. - The instability leads to the formation of rapidly advancing, wormhole-like channels.


Inversion for the Input History of a Dye Tracing Experiment, 2011, Field M. S. , Li G.

The advection-dispersion model (ADM) is a good tool for simulating transport of dye or solutes in a solution conduit. Because the general problem of transport can be decomposed into two problems, a boundary-value problem and an initial-value problem, the complete solution is a superposition of the solutions for these two problems. In this paper, the solution for the general problem is explained. A direct application of the solution for the boundary-value problem is dye-tracing experiments. The purpose is inclusion of the input history of a solute dye into the ADM. The measured breakthrough curve of a dye-tracing experiment is used to invert for the release history of the dye at the input point through the ADM. It is mathematically shown that the breakthrough curve can not be directly used to invert for the boundary condition at a tracer release point. Therefore, a conductance-fitting method is employed to obtain the input history. The inverted history for a simple example is then shown to be a step function with amplitude of 420 mg/L and a duration of 10 minutes. Simulations illustrate that the breakthrough curves at downstream springs provide a means for understanding the migration of dye. A discussion of the implication of the solution for an initial-value problem (e.g., simulating transport of preexisting solutes such as dissolved calcium carbonate in solution conduits) is also included.


A preliminary analysis of failure mechanisms in karst and man-made underground caves in Southern Italy, 2011, Parise M. , Lollino P.

Natural and anthropogenic caves may represent a potential hazard for the built environment, due to the occurrence of instability within caves, that may propagate upward and eventually reach the ground surface, inducing the occurrence of sinkholes. In particular, when caves are at shallow depth, the effects at the ground surface may be extremely severe. Apulia region (southern Italy) hosts many sites where hazard associated with sinkholes is very serious due to presence of both natural karst caves and anthropogenic cavities, the latter being mostly represented by underground quarries. The Pliocene–Pleistocene calcarenite (a typical soft rock) was extensively quarried underground, by digging long and complex networks of tunnels. With time, these underground activities have progressively been abandoned and their memory lost, so that many Apulian towns are nowadays located just above the caves, due to urban expansion in the last decades. Therefore, a remarkable risk exists for society, which should not be left uninvestigated.

The present contribution deals with the analysis of the most representative failure mechanisms observed in the field for such underground instability processes and the factors that seem to influence the processes, as for example those causing weathering of the rock and the consequent degradation of its physical and mechanical properties. Aimed at exploring the progression of instability of the cavities, numerical analyses have been developed by using both the finite element method for geological settings represented by continuous soft rock mass, and the distinct element method for jointed rock mass conditions. Both the effects of local instability processes occurring underground and the effects of the progressive enlargement of the caves on the overall stability of the rock mass have been investigated, along with the consequent failure mechanisms. In particular, degradation processes of the rock mass, as a consequence of wetting and weathering phenomena in the areas surrounding the caves, have been simulated. The results obtained from the numerical simulations have then been compared with what has been observed during field surveys and a satisfactory agreement between the numerical simulations and the instability processes, as detected in situ, has been noticed.


A Leaky-Conduit Model of Transient Flow in Karstic Aquifers, 2011, Loper David E. , Chicken Eric

Karst Flow Model (KFM) simulates transient flow in an unconfined karstic aquifer having a well-developed conduit system. KFM treats the springshed as a two-dimensional porous matrix containing a triangulated irregular network of leaky conduits. The number and location of conduits can be specified arbitrarily, perhaps using field information as a guide, or generated automatically. Conduit networks can be tree-like or braided. Rainwater that has infiltrated down from the surface leaks into the conduits from the adjacent porous matrix at a rate dictated by Darcy’s law, then flows turbulently to the spring via the conduits. KFM is calibrated using the known steady state; geometry and recharge determine the steady fluxes in the conduits, and the head distribution determines conduit gradients and sizes. Spring flow can vary with time due to spatially and temporally variable recharge and due to prescribed variations in the elevation of the spring. KFM is illustrated by four examples run on a test aquifer consisting of 27 nodes, 42 elements, and 26 conduits. Three examples (drought, uniform rainstorm, storm-water input to one element) are simulations, while the fourth uses data from a spring-basin flooding event. The qualitative fit between the predicted and observed spring discharge in the fourth example provides support of the hypothesis that the dynamic behavior of a karst conduit system is an emergent property of a self-organized system, largely independent of the locations and properties of individual conduits.


Influence of Karst Landscape on Planetary Boundary Layer Atmosphere: A Weather Research and Forecasting (WRF) ModelBased Investigation, 2011, Leeper R. Mahmood R, Quintanar A. I.

Karst hydrology provides a unique set of surface and subsurface hydrological components that affect soilmoisture variability. Over karst topography, surface moisture moves rapidly below ground via sink holes,vertical shafts, and sinking streams, reducing surface runoff and moisture infiltration into the soil. In addition,subsurface cave blockage or rapid snowmelt over karst can lead to surface flooding. Moreover, regionsdominated by karst may exhibit either drier or wetter soils when compared to nonkarst landscape. However,because of the lack of both observational soil moisture datasets to initialize simulations and regional landsurface models (LSMs) that include explicit karst hydrological processes, the impact of karst on atmosphericprocesses is not fully understood. Therefore, the purpose of this study was to investigate the importance ofkarst hydrology on planetary boundary layer (PBL) atmosphere using the Weather Research and ForecastingModel (WRF). This research is a first attempt to identify the impacts of karst on PBL. To model the influenceof karst hydrology on atmospheric processes, soil moisture was modified systematically over the WesternKentucky Pennyroyal Karst (WKYPK) region to produce an ensemble of dry and wet anomaly experiments.Simulations were conducted for both frontal- and nonfrontal-based convection. For the dry ensemble, cloudcover was both diminished downwind of karst because of reduced atmospheric moisture and enhanced slightlyupwind as moist air moved into a region of increased convection compared to control simulations (CTRL).Moreover, sensible (latent) heat flux and PBL heights were increased (decreased) compared to CTRL. Inaddition, the wet ensemble experiments reduced PBL heights and sensible heat flux and increased cloud coverover karst compared to CTRL. Other changes were noted in equivalent potential temperature (ue) andvertical motions and development of new mesoscale circulation cells with alterations in soil moisture overWKYPK. Finally, the location of simulated rainfall patterns were altered by both dry and wet ensembles withthe greatest sensitivity to simulated rainfall occurring during weakly forced or nonfrontal cases. Simulatedrainfall for the dry ensemble was more similar to the North American Regional Reanalysis (NARR) thanCTRL for the nonfrontal case. Furthermore, the initial state of the atmosphere and convective triggers werefound to either enhance or diminish simulated atmospheric responses


Carbonate Aquifers, 2012, Cunningham K. J. , Sukop M. C. , Curran H. A.

Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.


Carbonate Aquifers, 2012, Cunningham K. J. , Sukop M. C. , Curran H. A.

Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.


Evaluation of permeability and non-Darcy flow in vuggy macroporous limestone aquifer samples with lattice Boltzmann methods, 2013, Sukop M. C. , Huang H. , Alvarez P. F. , Variano E. A. , Cunningham K. J.

Lattice Boltzmann flow simulations provide a physics-based means of estimating intrinsic permeability from pore structure and accounting for inertial flow that leads to departures from Darcy’s law. Simulations were used to compute intrinsic permeability where standard measurement methods may fail and to provide better understanding of departures from Darcy’s law under field conditions. Simulations also investigated resolution issues. Computed tomography (CT) images were acquired at 0.8 mm interscan spacing for seven samples characterized by centimeter-scale biogenic vuggy macroporosity from the extremely transmissive sole-source carbonate karst Biscayne aquifer in southeastern Florida. Samples were as large as 0.3 m in length; 7–9 cm-scale-length subsamples were used for lattice Boltzmann computations. Macroporosity of the subsamples was as high as 81%. Matrix porosity was ignored in the simulations. Non-Darcy behavior led to a twofold reduction in apparent hydraulic conductivity as an applied hydraulic gradient increased to levels observed at regional scale within the Biscayne aquifer; larger reductions are expected under higher gradients near wells and canals. Thus, inertial flows and departures from Darcy’s law may occur under field conditions. Changes in apparent hydraulic conductivity with changes in head gradient computed with the lattice Boltzmann model closely fit the Darcy-Forchheimer equation allowing estimation of the Forchheimer parameter. CT-scan resolution appeared adequate to capture intrinsic permeability; however, departures from Darcy behavior were less detectable as resolution coarsened.


GLACIER ICE-CONTACT SPELEOGENESIS, 2013, Lauritzen S. E. Skoglund R. Ø, .

 

The classic hypothesis of G. Horn’s (1935) subglacial speleogenesis as an explanation of the relatively small diameter cave conduits in the Scandinavian marble stripe karst is reviewed. Recent work, including accurate cave mapping and morphological analysis, radiometric dating of cave deposits, chemical kinetics experiments and computer simulations have challenged the old theory. Scandinavia has relatively small caves that often have surprisingly high ages, going beyond the limit of Th/U dating. The high ages are apparently compensated by correspondingly slow wall retreat rates in the icecontact regime, and longer periods when the caves were inactive. Ice-contact speleogenesis varied in time and space, in pace with waxing and waning of wet-based ice. Maze or labyrinth morphology appears as a characteristic feature of caves ascribed to these processes.


Deep 3D thermal modelling for the city of Berlin (Germany), 2013, Sippel Judith, Fuchs Sven, Cacace Mauro, Braatz Anna, Kastner Oliver, Huenges Ernst, Scheckwenderoth Magdalena

This study predicts the subsurface temperature distribution of Germany’s capital Berlin. For this purpose, a data-based lithosphere-scale 3D structural model is developed incorporating 21 individual geological units. This model shows a horizontal grid resolution of (500 9 500) m and provides the geometric base for two different approaches of 3D thermal simulations: (1) calculations of the steadystate purely conductive thermal field and (2) simulations of coupled fluid flow and heat transport. The results point out fundamentally different structural and thermal configurations for potential geothermal target units. The top of the Triassic Middle Buntsandstein strongly varies in depth (159–2,470 m below sea level) and predicted temperatures (15–95 _C), mostly because of the complex geometry of the underlying Permian Zechstein salt. The top of the sub-salt Sedimentary Rotliegend is rather flat (2,890–3,785 m below sea level) and reveals temperatures of 85–139 _C. The predicted 70 _C-isotherm is located at depths of about 1,500–2,200 m, cutting the Middle Buntsandstein over large parts of Berlin. The 110 _C-isotherm at 2,900–3,700 m depth widely crosscuts the Sedimentary Rotliegend. Groundwater flow results in subsurface cooling the extent of which is strongly controlled by the geometry and the distribution of the Tertiary Rupelian Clay. The cooling effect is strongest where this clay-rich aquitard is thinnest or missing, thus facilitating deep-reaching forced convective flow. The differences between the purely conductive and coupled models highlight the need for investigations of the complex interrelation of flow- and thermal fields to properly predict temperatures in sedimentary systems.


Deep 3D thermal modelling for the city of Berlin (Germany), 2013, Sippel Judith, Fuchs Sven, Cacace Mauro, Braatz Anna, Kastner Oliver, Huenges Ernst, Scheckwenderoth Magdalena

This study predicts the subsurface temperature distribution of Germany’s capital Berlin. For this purpose, a data-based lithosphere-scale 3D structural model is developed incorporating 21 individual geological units. This model shows a horizontal grid resolution of (500 9 500) m and provides the geometric base for two different approaches of 3D thermal simulations: (1) calculations of the steady state purely conductive thermal field and (2) simulations of coupled fluid flow and heat transport. The results point out fundamentally different structural and thermal configurations for potential geothermal target units. The top of the Triassic Middle Buntsandstein strongly varies in depth (159–2,470 m below sea level) and predicted temperatures (15–95 _C), mostly because of the complex geometry of the underlying Permian Zechstein salt. The top of the sub-salt Sedimentary Rotliegend is rather flat (2,890–3,785 m below sea level) and reveals temperatures of 85–139 _C. The predicted 70 _C-isotherm is located at depths of about 1,500–2,200 m, cutting the Middle Buntsandstein over large parts of Berlin. The 110 _C-isotherm at 2,900–3,700 m depth widely crosscuts the Sedimentary Rotliegend. Groundwater flow results in subsurface cooling the extent of which is strongly controlled by the geometry and the distribution of the Tertiary Rupelian Clay. The cooling effect is strongest where this clay-rich aquitard is thinnest or missing, thus facilitating deep-reaching forced convective flow. The differences between the purely conductive and coupled models highlight the need for investigations of the complex interrelation of flow- and thermal fields to properly predict temperatures in sedimentary systems.


Early-stage hypogene karstification in a mountain hydrologic system: A coupled thermohydrochemical model incorporating buoyant convection, 2013, Chaudhuri A. , Rajaram H. , Viswanathan H

The early stage of hypogene karstification is investigated using a coupled thermohydrochemical model of a mountain hydrologic system, in which water enters along a water table and descends to significant depth (_1 km) before ascending through a central high-permeability fracture. The model incorporates reactive alteration driven by dissolution/ precipitation of limestone in a carbonic acid system, due to both temperature- and pressuredependent solubility, and kinetics. Simulations were carried out for homogeneous and heterogeneous initial fracture aperture fields, using the FEHM (Finite Element Heat and Mass Transfer) code. Initially, retrograde solubility is the dominant mechanism of fracture aperture growth. As the fracture transmissivity increases, a critical Rayleigh number value is exceeded at some stage. Buoyant convection is then initiated and controls the evolution of the system thereafter. For an initially homogeneous fracture aperture field, deep well-organized buoyant convection rolls form. For initially heterogeneous aperture fields, preferential flow suppresses large buoyant convection rolls, although a large number of smaller rolls form. Even after the onset of buoyant convection, dissolution in the fracture is sustained along upward flow paths by retrograde solubility and by additional ‘‘mixing corrosion’’ effects closer to the surface. Aperture growth patterns in the fracture are very different from those observed in simulations of epigenic karst systems, and retain imprints of both buoyant convection and preferential flow. Both retrograde solubility and buoyant convection contribute to these differences. The paper demonstrates the potential value of coupled models as tools for understanding the evolution and behavior of hypogene karst systems.


Early-stage hypogene karstification in a mountain hydrologic system: A coupled thermohydrochemical model incorporating buoyant convection, 2013, Chaudhuri A. , Rajaram H. , Viswanathan H.

The early stage of hypogene karstification is investigated using a coupled
thermohydrochemical model of a mountain hydrologic system, in which water enters along a
water table and descends to significant depth (1 km) before ascending through a central
high-permeability fracture. The model incorporates reactive alteration driven by dissolution/
precipitation of limestone in a carbonic acid system, due to both temperature- and pressuredependent
solubility, and kinetics. Simulations were carried out for homogeneous and
heterogeneous initial fracture aperture fields, using the FEHM (Finite Element Heat and Mass
Transfer) code. Initially, retrograde solubility is the dominant mechanism of fracture aperture
growth. As the fracture transmissivity increases, a critical Rayleigh number value is exceeded
at some stage. Buoyant convection is then initiated and controls the evolution of the system
thereafter. For an initially homogeneous fracture aperture field, deep well-organized buoyant
convection rolls form. For initially heterogeneous aperture fields, preferential flow suppresses
large buoyant convection rolls, although a large number of smaller rolls form. Even after the
onset of buoyant convection, dissolution in the fracture is sustained along upward flow paths
by retrograde solubility and by additional ‘‘mixing corrosion’’ effects closer to the surface.
Aperture growth patterns in the fracture are very different from those observed in simulations
of epigenic karst systems, and retain imprints of both buoyant convection and preferential
flow. Both retrograde solubility and buoyant convection contribute to these differences. The
paper demonstrates the potential value of coupled models as tools for understanding the
evolution and behavior of hypogene karst systems.


Early-stage hypogene karstification in a mountain hydrologic system: A coupled thermohydrochemical model incorporating buoyant convection, 2013, Chaudhuri A. , Rajaram H. , Wiswanathan H.

The early stage of hypogene karstification is investigated using a coupled thermohydrochemical model of a mountain hydrologic system, in which water enters along a water table and descends to significant depth (_1 km) before ascending through a central high-permeability fracture. The model incorporates reactive alteration driven by dissolution/ precipitation of limestone in a carbonic acid system, due to both temperature- and pressuredependent solubility, and kinetics. Simulations were carried out for homogeneous and heterogeneous initial fracture aperture fields, using the FEHM (Finite Element Heat and Mass Transfer) code. Initially, retrograde solubility is the dominant mechanism of fracture aperture growth. As the fracture transmissivity increases, a critical Rayleigh number value is exceeded at some stage. Buoyant convection is then initiated and controls the evolution of the system thereafter. For an initially homogeneous fracture aperture field, deep well-organized buoyant convection rolls form. For initially heterogeneous aperture fields, preferential flow suppresses large buoyant convection rolls, although a large number of smaller rolls form. Even after the onset of buoyant convection, dissolution in the fracture is sustained along upward flow paths by retrograde solubility and by additional ‘‘mixing corrosion’’ effects closer to the surface. Aperture growth patterns in the fracture are very different from those observed in simulations of epigenic karst systems, and retain imprints of both buoyant convection and preferential flow. Both retrograde solubility and buoyant convection contribute to these differences. The paper demonstrates the potential value of coupled models as tools for understanding the evolution and behavior of hypogene karst systems.


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