Karst and Cave RSS news feed Like us on Facebook! follow us on Twitter!
Community news

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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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. ...

Did you know?

That cavernous karren is pitted, rubbly limestone most commonly found in relatively recent and tertiary limestones of the humid tropics [3]. see also covered karren; karren.?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

What is Karstbase?

Search KARSTBASE:

keyword
author

Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
Engineering challenges in Karst, Stevanović, Zoran; Milanović, Petar
See all featured articles
Featured articles from other Geoscience Journals
Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy), Dimuccio, L.A.; Rodrigues, N.; Larocca, F.; Pratas, J.; Amado, A.M.; Batista de Carvalho, L.A.
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
See all featured articles from other geoscience journals

Search in KarstBase

Your search for erosion rate (Keyword) returned 27 results for the whole karstbase:
Showing 1 to 15 of 27
Surface Lowering and Landform Evolution on Aldabra, 1979, Trudgill S. T. ,
Aldabra landforms are the result of the karstification of carbonate rocks distributed on surfaces which have been exposed to erosion for varying lengths of time. Morphometric analysis (which is of interest in both geomorphological and botanical contexts) suggests that the most well developed karst features (closed depressions) occur on what appear to be the oldest surfaces. Morphology also varies with lithology. Measurements of present-day erosion rates suggests that weakly cemented rocks and the most soluble mineral components are eroding most rapidly. The evolution of a dissected morphology is related to lithological heterogeneity in coralline rocks or, in the case of the more homogeneous rocks, to the short residence time of waters on the rock surface (the more rapidly dissolving mineral grains eroding faster). Dissolution also proceeds in fresh water pools, but this may be offset by precipitation in some cases. The surface is mostly case hardened, except under deep organic soils where erosion rates are much higher than in other areas. A mean erosion rate measured at 0.26 mm/a appears to make it feasible that large erosional features, such as the lagoon, could have been formed during periods of emersion as suggested by research workers who have hypothesized that an atoll shape may be substantially derived by subaerial weathering

Water Chemistry of the Atea Kananda and the Related Drainage Area, 1980, James, Julia M.

The Ca2+, Mg2+, alkalinity, pH and temperature have been measured in water from the Atea Kananda cave and related surface sites on the Muller Plateau (Papua New Guinea). A wide variation in the Ca2+ and Mg2+ values was found and this has been attributed to the lithology and nature (open or closed) of the water courses. From alkalinity measurements anions other than bicarbonate, probably sulphate are expected to be present in significant quantities in the cave waters. Most of the waters are aggressive. The Ca2+/Mg2+ x 10 ratio is shown to be a useful tool in predicting the origin of unknown waters in the cave. The variations of the measured and calculated parameters for groups of related surface and underground sites are presented and discussed. Tentative solution erosion rates for the Muller Plateau have been calculated and the conclusion reached that where the erosion can be placed as largely occuring on pure limestone these are high. Impure limestones and non-calcareous rocks in their catchments give anomalously low results for the main rivers. A scheme for cave development on the Muller Plateau by solution mechanisms is presented.


A comparison of the rock tablet and water hardness methods for determining chemical erosion rates on karst surfaces, 1983, Crowther J.

Further Studies At The Blue Waterholes, Cooleman Plain, N.S.W., 1969-77, Part II, Water Chemistry And Discussion, 1983, Jennings, J. N.

The 1969-77 data confirm that groundwater temperature is significantly higher than air temperature at mean catchment altitude but provide only partial support for an explanation in terms of soil temperature and insulation of drainage from cold air ponding over the Plain. Higher pH of output than input streams is attributed mainly to percolation water chemistry. Water chemistry of two contrasted input streams suggests non-karst rock weathering has an important effect on allogenic input streams. An inverse relationship between carbonate hardness and output discharge is found again and attributed mainly to faster transit through the limestone at high flows. Summer has a steeper regression than winter due to precipitation and high flows depressing carbon dioxide and carbonate concentrations more in that season than in winter. Picknett graphs show how solutional capacity varies through the hydrologic system, with aggressive input streams, mainly saturated percolation water, and rarely saturated output springs because of the allogenic component in the last. The total carbonate load of Cave Creek is directly related to discharge, with little seasonal difference so the annual regression is chosen for later calculation. When the carbonate load duration curve and frequency classes for Cave Creek are compared with those for other karsts, it falls into an intermediate class in which neither very high nor low flows dominate the pattern. This is attributed to a combination of a large allogenic input with a complex routing pattern. Consideration of most input stream solute concentration on one occasion indicates such close dependence on catchment geology that doubt is cast on the smallness of the 1965-9 allocation of carbonate contribution from non-karst rock weathering to the allogenic input. This is explained by new CSIRO rainfall chemistry figures from the Yass R. catchment which are smaller than those used before and by elimination of a previous error in calculation. This time subtraction of atmospheric salts is done on a daily basis with a decaying hyperbolic function. Correction of Cave Creek output for allogenic stream input follows the method adopted in 1965-9 but on a firmer basis, with the assumption of approximately equal water yeild per unit area from the non-karst and karst parts of the catchment being more factually supported than before. It remains a substantial correction. The correction for subjacent karst input to Cave Creek is also improved by putting the calculation in part on a seasonal basis; it remains small. The exposed solute load output shows the same seasonal pattern as was determined earlier, with a winter/spring maximum, and it again evinced much variation from year to year. So did annual rates. The mean annual loss of 29 B was slightly greater than for 1965-9. If this difference is real and not an experimental error, the reduced allowance for atmospheric salts and greater annual rainfall in the second period could explain the increase. This erosion rate of 29 B from an annual runoff of about 400mm places this karst where it would be expected in the world pattern of similar determinations in terms of both runoff and its proximity to the soil covered/bare karst dichotomy of Atkinson and Smith (1976). Combined with the other work at Cooleman Plain on erosion at specific kinds of site, an estimate of the spatial distribution of the limestone solution is presented. It agrees well with the similar attempt for Mendip by Atkinson and Smith (1976), when allowance is made for certain differences in method and context. The main conclusions are the great role of solution in the superficial zone and the unimportance of the contribution from caves. Conflict between this process study and the geomorphic history of Cooleman Plain remains and once again an explanation is sought in long persistence of a Tertiary ironstone cover inhibiting surface solution.


Carbonate erosion rates in southwestern Wisconsin, 1984, Day M. J.

LIMESTONE WEATHERING IN EASTERN AUSTRALIA .1. EROSION RATES, 1995, Smith D. I. , Greenaway M. A. , Moses C. , Spate A. P. ,
A traversing microerosion meter (MEM) was used to measure the rates of surface weathering of limestones in southeastern Australia. There were two groups of MEM sites installed in 1978/9. The aim of the experimental design for the first type, the 13 sites at Cooleman Plain and Yarrangobilly Caves, was to obtain erosion rates for limestones of similar lithology exposed under comparable climate conditions. The sites were positioned to measure erosion over a range of microsolutional forms and with exposure to differing forms of erosion, i.e. subaerial, subsoil and instream. The second set, at Ginninderra close to Canberra, consists of nine limestone slabs of differing lithology, collected from different locations but exposed under identical climatic conditions. The number of individual measurement points at each MEM site varied from 24 to 68. There were major differences in erosion rates between subaerial bedrock and instream sites at Yarrangobilly and Cooleman Plain, but no evidence of differential erosion across the micro-forms. There were differences in the weathering rate for bedrock sites, due to climatic differences, and between the limestone lithologies exposed at Ginninderra. The average rate of erosion for the subaerial bedrock sites at Cooleman Plain and Yarrangobilly over the 13 years was 0.013 mm a(-1) and at Ginninderra 0.006 mm a(-1). At some of the sites microflora (lichens and mosses) caused problems for field measurement. The weathering processes that contribute to the surface lowering are discussed in the accompanying paper by Moses ef al

Some preliminary results of micrometric measurements in kocjanske caves, Slovenia, 1996, Mihevc, Andrej

Flow dynamics and erosion rate of a representative karst basin (Upper Aniene River, Central Italy), 1996, Bono P, Percopo C,

Mineralogy of speleothems from caves in the Padurea Craiului Mountains and their palaeoclimatic significance, PhD thesis, 1996, Onac, B. P.

The thesis comprises an introductory section, which provides the reader with the basic geologic, tectonic and speleologic setting of the study area in the karst of Padurea Craiului Mountains and is then divided into a mineralogical/crystallographical study and a geochronological study. The mineralogical and crystallographical investigations were based on traditional and modern methods of laboratory techniques (X-ray, thermal, infra-red, scanning electron microscope and thermal ionisation mass-spectrometric analysis) and have given several new aspects concerning the morphology and origin of cave speleothems (for example, anthodites, oulopholites, fungites). Following detailed investigations on some moonmilk speleothems, a new classification system has been proposed. The results of this first part of the thesis lead into a discussion of the conditions of formations of the studied cave minerals and their morphology.
The second part (geochronology) is dedicated to speleothem dating and contains details of the 230Th/234U chronometer and its application. The various sampling sites (caves) are presented, as well as a list of uranium-series dates. Although there are relatively few data (65), a discussion of the distribution of the ages in time and with respect to Pleistocene climate has been undertaken. It is reported that the speleothems from the Padurea Craiului Mountains display less pronounced growth intervals than those from north-western Europe.
The thesis also examines the use of caves (via speleothem dating) to obtain rates of landscape evolution. The maximum average erosion rates for the Crisul Repede basin are in the range, 0.43-046 m/1000 years. These rates represent both glacial and interglacial conditions, and compare well with rates determined from other countries. A list of minerals which form cave speleolhems is given in an Appendix. The list was compiled from the literature and updated with the author's investigations. It includes the mineral name, composition, crystal system and class, and frequency.


Contribution to knowledge of gypsum karstology, PhD thesis, 1998, Calaforra Chordi, J. M.

The objective of this study was not to establish a definitive judgement regarding a topic for which very little previous information was available, but rather to open new routes for research into karst by means of a particularized analysis of some of the factors involved in the speleogenesis of gypsiferous materials. The main obstacle to the attainment of this goal has been the scientific community's lack of interest in karst in gypsum, particularly in our country, until the nineteen eighties. To overcome this neglect it was decided, in my opinion quite correctly, to extend the bounds of the study as far as possible, so that the information obtained from the contrast found between the most important worldwide zones of karst in gypsum could be applied to the gypsiferous karst in our country, and in particular, to the most significant, the karst in gypsum of Sorbas.
This is the justification for the numerous references in the text to the gypsiferous karst and cavities in gypsum that are most relevant in Spain (Sorbas, Gobantes, Vallada, Archidona, Estremera, Baena, the Ebro Basin, Estella, Beuda, Borreda, etc.) and also to the best-known gypsiferous karsts worldwide (Podolia, Secchia, Venna del Gesso Romagnolo, Sicily and New Mexico). By means of these comparisons, the initial lack of information has been overcome.
The study is based on three central tenets, which are interrelated and make up the first three chapters of this report. The first consideration was to attempt to characterize the particular typology of gypsiferous karst from the geological (both stratigraphic and structural) point of view. This chapter also provides an introduction to each of the gypsiferous karsts examined. The second chapter is dedicated to the geomorphology of gypsiferous karst, under both superficial and subterranean aspects. It is important to note that the study of a gypsiferous karst from the speleological point of view is something that may seem somewhat unusual; however, this is one of the points of principle of this paper, the attempt to recover the true meaning of a word that has historically been unfairly condemned by a large part of the Spanish scientific community. Thirdly, a detailed study has been made of the hydrochemistry of the most important gypsiferous karsts in our region, together with the presentation of a specific analytical methodology for the treatment of the hydrochemical data applicable to the gypsiferous karst.
Geological characterization of gypsum karst
In the characterization of karst in gypsum, the intention was to cover virtually all the possibilities from the stratigraphic and structural standpoints. Thus, there is a description of widely varying gypsiferous karsts, made up of Triassic to Miocene materials, some with a complex tectonic configuration and others hardly affected by folding. The gypsiferous karsts described, and their most significant geological characteristics, are as follows:
Karst in gypsum at Sorbas (Almeria): composed of Miocene gypsiferous levels with the essential characteristic of very continuous marly interstrata between the layers of gypsum, which decisively affect the speleogenesis of the area. The gypsum layers have an average thickness of about 10 m and, together with the fracturing in the zone, determine the development of the gypsiferous cavities. These are mainly selenitic gypsum - occasionally with a crystal size of over 2 m - and their texture also has a geomorphologic and hydrogeologic influence. This area is little affected by folding and so the tectonic influence of speleogenesis is reduced to the configuration of the fracturing.
The Triassic of Antequera (Malaga): this is, fundamentally, the gypsiferous outcrop at Gobantes-Meliones, originating in the Triassic and located within the well-known "Trias" of Antequera. It is made up of very chaotic gypsiferous materials containing a large quantity of heterometric blocks of varied composition; the formation may be defined as a Miocene olitostromic gypsiferous breccia that is affected by important diapiric phenomena. The presence of hypersoluble salts at depth is significant in the modification of the hydrochemical characteristics of the water and in the speleogenetic development of the karst.
The Triassic of Vallada (Valencia): Triassic materials outcrop in the Vallada area; these mainly correspond to the K5 and K4 formations of the Valencia Group, massive gypsum and gypsiferous clays. The influence of dolomitic intercalations in the sequence is crucial to the speleogenesis of the area and this, together with intense tectonic activity, has led to the development in this sector of the deepest gypsiferous cavity in the world: the "Tunel dels Sumidors". As in the above case, the presence of hypersoluble salts at depth and the varied lithology influence the variations in the hydrodynamics and hydrochemistry of the gypsiferous aquifer.
Other Spanish gypsum karsts: this heading covers a group of gypsiferous areas and cavities of significant interest from the speleogenetic standpoint. They include the area of Estremera (Madrid), with Miocene gypsiferous clays and massive gypsum arranged along a large horizontal layer; this has produced the development of the only gypsiferous cavity in Spain with maze configuration, the Pedro Fernandez cave. The study of this cave has important hydrogeological implications with respect to speleogenesis in gypsum in phreatic conditions. The Baena (Cordoba) sector, in terms of its lithology, is comparable to the "Trias de Antequera". Here, the cavities developed in gypsiferous conglomerates, following structural discontinuities have enabled contact between carbonate and gypsiferous levels, and so we may speak of a mixed karstification: a karst in calcareous rocks and gypsum. The karst of Archidona (Malaga) is similar to that of the Gobantes-Meliones group and is significant because of the geomorphologic evolution of the karst, which is related to the diapiric ascent of the area and the formation of karstic ravines. The karst in the Miocene and Oligocene gypsum of the Ebro Basin (Zaragoza), has been taken as a characteristic example of a gypsiferous karst developed under an alluvial cover, with the corresponding geomorphological implications in the evolution of the surface landforms. In the gypsiferous area of Borreda (Barcelona), the presence of anhydritic levels in the sequence might have influenced the speleogenesis of its cavities. The cavity of La Mosquera, in Beuda (Girona), developed in massive Paleogene gypsum. This is the only Spanish example of a phreatic gypsiferous cavity developed in saccaroid gypsum, which is related to the particular subterranean morphology discovered. Finally, this group includes other Spanish gypsiferous outcrops visited during the preparation of this report, the references to which may be found in the relevant chapters.
Karst in gypsum in Europe and America: In order to complete the study of karst in gypsum, and with the idea of using all the available data on the karstology of gypsiferous materials for comparative studies of data for our country, a complementary activity was to define the most significant geological characteristics of the most important gypsiferous karsts in the world. An outstanding example is the gypsiferous karst at Podolia (Ukraine), developed in microcrystalline Miocene gypsum which has undergone block tectonics related to the collapse of the Precarpatic foredeep. This gypsum provides interesting data on speleogenesis in gypsiferous materials, as its evolution is related to the confining of the only gypsiferous stratum (of 10 to 20 m depth) producing interconnected labyrinthine galleries of over 100 km in length. Another well-known karst in gypsum is the one located at "Venna del Gesso Romagnolo" (Italy), in the Bologna region, with a lithology that is very similar to that which developed at Sorbas, but with the difference that it underwent more intense tectonics with folding and fracturing of the Tertiary sediments of the Po basin. In the same Italian province, in "L'alta Val di Sec-chia", there are outcrops of karstified Triassic materials which correspond to the formation of Burano, composed of gypsum and anhydrite with hypersoluble salts at depth and very notable diapiric phenomena. The study of this area has been used for a comparative analysis - geomorphology and hydrogeochemistry - with the Spanish gypsiferous karsts developed in Triassic levels. The third Italian gypsiferous karst to be considered is the one developed in Sicily, which has extensive Messinian outcrops of microcrystalline and selenitic gypsum as well as a great variety of lithologic types within the gypsiferous sequence, which we term the "gessoso solfifera" sequence. This gypsiferous karst is especially interesting from the geomorphologic standpoint due to the great quantity and variety of present superficial karstic forms. This has also served as a guide for the study of Spanish gypsiferous karsts. Finally, considering the relation between climatology and the development of karstic forms, we have also studied the karst in gypsum in New Mexico, where there is an extensive outcrop of Permian gypsum, both micro and macrocrystalline, situated on a large platform almost unaffected by deformation, and where the conditions of aridity are very similar to those found in the gypsiferous karst of Sorbas.
Geomorphological characterization of gypsum karst
From the geomorphological standpoint, the intention is to give an overview of the great variety of karstic forms developed in gypsum, traditionally considered less important than those developed in carbonate areas. This report shows this is not the case.
The theory of Convergence of Forms has been shown to be an efficient tool for the study of the morphology of karst in gypsum. Here, its principles have been used to provide genetic explanations for various gypsiferous forms derived from carbonate studies, and for the reverse case. In fact, studying a karst in gypsum is like having available a geomorphological laboratory where not only are the processes faster but they are also applicable to the karstology of carbonate rocks.
A large number of minor karstic forms (Karren) have been identified. The most important factors conditioning their formation are the texture of the rock, climatology and the presence of overlying deposits. The first, particularly, is largely responsible for determining the abundance of certain forms with respect to others. Thus, Rillenkarren, Trittkarren and small "kamenitzas" are more frequently found in microcrystalline and sandstone gypsum (for example, karst in gypsum in Sicily (Italy) and Va-llada (Valencia, Spain). Others seem to be more exclusive to selenitic gypsum, such as exfoliation microkarren, or are closely related to the climatology of the area (Spitzkarren develops from the alteration of gypsum in semiarid conditions). Others are related either to the presence of developed soil cover (Rundkarren, using Convergence of Forms), or to their specific situation (candelas and Wallkarren around dolines and sinkholes) or to the microtexture of the gypsum and the orientation of the 010 and 111 crystalline planes and twinning planes for the development of nanokarren.
The tumuli are the most peculiar forms of the Sorbas karst in gypsum, though they have also been identified in other gypsiferous karsts (Bolonia, New Mexico, Vallada, etc.). These are subcircular domes of the most superficial layer of the gypsum. Their formation has been related to processes of precipitation-solution and of capillary movement through the gypsiferous matrix. Their extensive development is largely determined by the climatology of the area and by the structural organization. It is therefore clear that the best examples are found in the karst of Sorbas due to the abrupt changes in temperature and humidity that occur in a semiarid climate, and because of the horizontality of the gypsiferous sequence.
Karst in gypsum and its larger exokarstic forms, apart from being climatically determined, also depend on the structural state and lithological determinants of the area. Thus, it is possible to differentiate between gypsiferous karsts where the lithology, together with erosive breakup, is more important (Sorbas and New Mexico) and others where confining hydraulic conditions persist (Estremera and Podolia). In other cases, tectonics has played a significant modelling role, and there is a clear possibility of an inversion of the relief (Bolonia or Sicily) or of the effect of diapiric processes (Secchia, Vallada, Antequera). The typological diversity of the dolines is obviously also related to these premisses. Another example is the relation existing between carbonate precipitation and gypsum solution, as evidenced in contrasting examples (Bolonia versus Sorbas).
Subterranean karstic forms have been examined from a double perspective: the morphology of the passages and the mineralization within the cavities. With respect to the former, a noteworthy example is the interstratification karst of Sorbas, where subterranean channels have developed during two well-differentiated phases, the phreatic and the vadose. The first was responsible for the formation of the small proto-galleries, currently relicts that are observable as false dome channels in the bottom of the gypsiferous strata. The second, with an erosive character, enabled the breakup of the marly interstrata and the formation of the large galleries found today. Other aspects considered include the speleogenetic influence of the presence of calcareous intercalations in the gypsiferous sequence (Vallada karst), gypsiferous agglomerates (Baena karst), anhydrite (Rotgers karst), suffusion processes (Sorbas karst) and the importance of condensation.
Spelothemes in gypsiferous cavities have been approached with special concern for gypsiferous speleothemes, in particular those which, due to their genetic peculiarity or to the lack of previous knowledge about them, are most significant. Among these are gypsum balls, with phenomena of solution, detritic filling, capillarity and evaporation; gypsum hole stalagmites, where the precipitation-solution of the gypsum controlling the formation of the central orifice is related to the previous deposit of carbonate speleothemes; gypsum trays that mark the levels of maximum evaporation; gypsum dust, determined by abrupt changes in temperature and humidity in areas near the exterior of gypsiferous cavities. All of these are characteristic of, and practically exclusive to, gypsiferous karsts in semiarid ztenes such as Sorbas and New Mexico.
Karst in gypsum has been morphologically classified with reference to the previously-mentioned criteria: the presence and typology of epigean karstic forms, both macro and microform; the typology of hypogean karstic forms (passages) and the type of speleothemes within the cavities (gypsiferous or carbonate). All these variables are clearly influenced by climatology, and so a study of the geomorphology of gypsiferous karst is seen to be an efficient tool for the analysis of the paleoclimatology of an area.
Hydrogeochemical characterization of gypsum karst
The hydrogeochemical characterization of karst in gypsum was approached in two stages. The first one was intended to establish themodels to be applied to the hydrochemistry approach, while the second provided various examples of hydrochemical studies carried out in gypsiferous karsts.
The theoretical framework which has been shown to be most accurate with respect to the formulation of chemical equilibria in water related to gypsiferous karst is the Virial Theory and the Pitzer equations.
For this study, we used a simplification of these equations as far as the second virial coefficient by means of a simple, polynomial variation to obtain the equilibrium state of the water with respect to the gypsum, for an ionic strength value greater than 0.1 m and temperatures of between 0.5 and 40 "C. This was the case of the gypsiferous karsts found to be related to hypersaline water at depth (Vallada, Gobantes-Meliones, Poiano). In the remaining situations, where the ionic strength was below 0.1 m, only the theory of ionic matching was used.
The hydrochemical study of the gypsiferous karst of Gobantes-Meliones (Malaga) led to the hypothesis of the possible influence of hypersaline water on karstification in gypsum. Using theoretical examples of the mixing of water derived both from hypersaline water and from water related only to the gypsiferous karst, it was shown that above a percentage content of 0.1:0.9 of saline and sulphated water, the mixture is subsaturated with respect to gypsum and other minerals. On reaching percentages greater than 0.5:0.5, values of oversaturation are again found. This could mean that the contact between sulphated and hypersaline water is a karstification zone in gypsum at depth.
In the gypsiferous karst at Salinas-Fuente Camacho (Granada), a study has been made of the hydrochemical influence of dolomitic levels in the sequence by means of the analysis of the hydrochemical routes between hydraulically-connected points. The generic case of mass transfer in this gypsiferous aquifer implies a precipitation of calcite which is in-congruent with dolomitic solution, proving that the process of dedolomitization in gypsiferous aquifers with an abundance of dolomitic rocks can be an effective process. In situations of high salinity, with contributions of hypersaline water, the process may be inverted, such as occurs in coastal carbonate aquifers influenced by the fresh-saltwater interface.
The gypsiferous aquifer of Sorbas-Tabernas (Almeria) provides the best case of karstification in gypsum in Spain; the hydrochemical study carried out has been used as an example of karstification in gypsum completely uninfluenced by sodium-chloride facies. It is shown, from the hydrochemical similarities between the different sectors, that the uniformity of the flow from the system main spring (Los Molinos) responds to the delayed hydraulic input through the overlying post-evaporitic materials and to the pelitic intercalations of the gypsiferous sequence. The aquifer is partially semiconfined, a situation which is comparable to the onset of the karstification stage, while the area of the Sorbas karst, strictly speaking, bears no hydriaulic relation to the rest of the system, behaving like a free aquifer intrinsically related to the epikarstic zone. This fact is demonstrated by the hydrochemical differences between the main spring and those related to gypsiferous cavities.
Apart from the general study of the Sorbas-Tabemas aquifer, a study was also made of the hydrochemical-time variations within cavities, and in particular within the Cueva del Agua, where it is possible to observe particular processes affecting karstification in gypsum, such as the precipitation of carbonates on the floor of the cavity which produce, in that area, a greater solution of gypsum (the phenomenon of hyperkarstification). Furthermore, the temporal evolution of the chemistry of the cavity, along 800 m of subterranean flow through its interior, shows the existence of inertial sectors where the variations were less abrupt. Only in the case of particular sectors, related to sporadic hydriaulic contributions or to the proximity to points of access., was a notable seasonal influence detected.
A similar hydrochemical study was carried out in the karst of Vallada (Valencia), along the cavity of the Tunel dels Sumidors. The chemistry here was compared with that of the springs of Brolladors (whose water rapidly infiltrates into the cavity) and Saraella (a saline resurgence of the whole system). Unexpected increases in the ionic content of certain salts (sulphates and chlorides) were detected during periods of increased flow; these were interpreted as the effect of the recharging of the Saraella spring arising from the immediate contribution of rapidly circulating sulfated water coming from the cavity and the subsequent mobilization of interstitial water with an ionic content higher than the characteristic level of the spring.
We present as a hypothesis the idea that, in addition to the hydrogeochemical processes described that can affect the evolution of a gypsiferous karst, the processes of sulphate reduction also influence karstification in gypsum, at least during the earliest stages. Some examples such as the presence of gypsum with abundant organic matter reprecipitated into phreatic channels (Sorbas) or veins of sulphur related to gypsiferous karsts (Podolia, Sicily) lend support to this idea.
Studies of the solution-erosion of gypsum have been performed by physical methods (tablets and M.E.M.) showing that the solution-erosion of gypsum within cavities is minimal (0.03 mm/ year) compared to that existing in the exterior (0.3 mm/year). The speleogenetic effect of condensation within the cavities has also been shown, with solution-erosion rates of 0.005 mm/year to be like the equivalent surface lowering. These data correspond to the karst in gypsum at Sorbas, where, additionally, a study about the time variation of the solution-erosion was carried out. It was found that the process is not continuous but clearly sporadic. During periods of torrential rain, the solution-erosion ranges from a weight loss of 400 mg/cm2/year on the surface of the karst to 75 mg/cm2/year inside the caves, while during the rest of the year the weight loss was barely 1 mg/cm2/year. The physical methods were compared with the results obtained from chemical methods, and it was found that, in general, higher values were obtained with the former (10-20% higher when weighted for the rainfall during the measuring periods). Thus it is reasonable to consider that the erosive process is more marked than was at first assumed.
In total, three cavity tracing experiments were carried out, all with fluoresceine, two of them in Cueva del Agua in Sorbas (during periods of high and low water levels) and the other in Tunel dels Sumidors in Vallada. At the first site, the comparison of the two tracing tests reveals a differential hydrodynamic behaviour of the cavity for the two contrasting situations; periods of high water input and periods of low rainfall. This behaviour is characteristic of well developed karstic aquifers, where the hydrodynamic effect of the circulation of water through small channels or, in this case, through the gypsiferous matrix and interbedded marly layers, seems to be more important under conditions of low hydraulic input than when rainfall is abundant. The two situations tested seem to confirm that the Cueva del Agua system, an epikarstic aquifer, which is representative of karstification in gypsum, has scarce retentive power and so large volumes of precipitation are totally discharged via the spring within a few days. However, the explanation of the small but continuous flow from the base of the cavity requires the inclusion of other factors in the interpretation. In this case, the flow seems to be fairly independent of rainfall and attributable to other processes, in addition to the previously described ones, such as the retentive power of the gypsiferous matrix and the marly interstrata. These might include the high degree of condensation measured over long periods, both on the surface of the karst in gypsum and within the cavities. In the case of the Tunel dels Sumidors, a highly irregular response was found, despite the fact that the coefficient of dispersivity was found to be 0.4. This value is similar to that obtained for the karst in gypsum at Sorbas in response to low water conditions, and so, here too, one might assume the influence of greater than expected flow-retaining processes, between the entry and exit points. Doubtless the karstic system of the Tunel dels Sumidors is more complex than was initially expected and in fact, the irregularity reflected by the fluoresceine concentration curve over time implies the existence of other factors to explain the diversity of the relative maxima obtained. Firstly, the presence of numerous Triassic clay intercalations might delay the flow, in addition to retaining a certain quantity of fluoresceine by ionic exchange. There is also a possibility that the flow is dispersed through a network of small conduits and pores, due to the permeability of the gypsiferous matrix. Finally, we cannot discount the possible existence of a deep-level input which, in this case, would be responsible for the variation in the flow and the chemical composition. This set of suppositions, as a whole, would explain the fact that the response of the spring to tracing is so irregular, even though we cannot achieve a definition of the qualitative influence of each one on the hydrodynamics of the system.
In order to verify some of the above hypotheses, particularly those referring to the process of condensation within cavities, an experiment was designed, consisting of a microtracing test at some points where condensation had been detected within the Cueva del Agua at Sorbas. The test produced a range of condensation flow speed values of 0.2 to 30 cm/hour and shows that, in those sections where the presence of condensation flow is visually apparent, there is a rapid dispersion of the colourant. However, it also shows that at points where there is no apparent condensation the process also occurs, but at a lower rate of efficiency. The importance of condensation within cavities has two aspects; firstly, speleogenetic, with the development of solution forms (cupolas) and deposit forms (capillarity boxwork); and secondly, hydrogeological, as this is the reason why certain processes (strong changes in temperature and humidity, multiple routes of airflow exchange with the exterior) may in themselves constitute a hydraulic contribution, of slight importance, but sufficient to explain a large part of the base flow (0.2 - 0.8 L/s) of a whole cavity system such as the Cueva del Agua in semiarid conditions.
With the intention of completing the analyses carried out in various karsts in gypsum, instruments were installed in the Cueva del Agua at Sorbas to measure, by continuous registration, some important physico-chemical parameters that might provide additional data on the hydro-geologic behaviour of this gypsiferous karst, especially at the level of the epikarstic zone. The parameters of temperature and water conductivity were considered most important, due to their singular behaviour patterns. During the experiment there were two periods of rainfall that modified the chemistry of the cavity, one of 30 mm in two days and another of 200 mm (almost the annual total) in four days. In the second case, which was much more extreme, a very significant increase in water temperature (up to 7 °C during the initial period of high water flow) was detected, while conductivity fell. But suddenly, when the minimum conductivity was reached, the temperature dropped sharply by 6-7 °C to return to the base temperature of the cavity. Subsequently, the temperature again stabilized at about 7 °C above the data recorded during the dry period. This behaviour pattern was not detected when the rainfall was slight. The explanation for this dual behaviour observed is fundamentally based on the quantity of rainfall and on the differences between the exterior air temperature, the temperature of interstitial water and the temperature recorded in the spring during high water flow. When water temperature in the cavity during high water flow is higher than the base temperature recorded in the period immediately before, it means that the interstitial water does not mobilize. However, when at any time the two temperatures coincide, one might suppose that there might have existed a process of mobilization of the water previously resident in the rock, by a piston effect, but in the unsaturated zone. On the other hand, the temporal variations of these parameters during the months following periods of high rainfall have enabled us to detect the existence of distinct periods during the return to normal cavity conditions. By carefully examining the decrease curve of water temperature inside the cavity while conductivity regained its maximum stable value, two periods may be differentiated. The first may be termed the "inertial influence period", when the rainfall occurring removes all signs of natural variation in the cavity. Thus, the daily external influences are not clearly detectable and the curve is downward-sloping and asymptotic with no significant oscillations. In the second period, which ends with the total stabilization of the parameter at the level of the initial conditions, the asymptotic descent is seen to be affected by daily temperature variations. This is termed the "inertial recovery period", during which external variations start to have an effect on the interior of the cavity such that there is a progressive increase in the amplitude of the daily variation in water temperature, air temperature and relative humidity. This behaviour pattern of variation of these parameters during periods of high rainfall, might be extended to all karstic systems, varying only in magnitude and temporal extent.


Solutional and erosional morphology, 2000, Lauritzen Se. , Lundberg J.
Caves are produced through the action of speleogenetic agents acting under various constraints to produce speleogenetic facies. These facies, expressed at the meso- and micro-scale, reflect the major and minor speleogenetic agents that operated on that cave; they also reflect the history of the cave, both during speleogenesis proper and during the post-speleogenetic phase, in particular the most recent history. Geological control is evident through the association of caves with guiding voids (the singularities that govern permeability) and passage shape with rock chemistry (solubility). Hydrological control guides the locus and direction of dissolution; phreatic conditions support omnidirectional dissolution and thus hydraulically controlled tubular forms, while vadose conditions allow only unidirectional dissolution and thus gravity-controlled canyon forms and karren-like features. Of the micro-forms, scallops are specific flow indicators that yield both directional and quantitative information like flow rates and various hydraulic parameters specific to the cave passages. The presence of a sediment fill may further direct corrosion; in the phreatic zone this causes paragenesis; in the vadose zone, sediments cause lateral undercutting and eventually collapse. Vadose streams display many of the forms of surface streams, such as migrating meanders, entrenchment, rock-mill pot-holes, and waterfalls. Vadose shafts, dome-pits and condensation-corrosional forms are perhaps specific to the cave enviroment. The various vadose, phreatic and certain water-table-specific forms are, in combination, powerful methods for reconstructing phases of speleogenesis as well as external base levels. Combined with speleothem dating techniques, they become important methods for determining erosion rates and landscape evolution.

Pliocene-Pleistocene incision of the Green River, Kentucky, determined from radioactive decay of cosmogenic 26Al and 10Be in Mammoth Cave sediments, 2001, Granger Darryl E. , Fabel Derek, Palmer Arthur N. ,
Cosmogenic 26Al and 10Be in sediments washed into Mammoth Cave, Kentucky, record the history of 3.5 m.y. of water-table position, governed by incision and aggradation of the Green River, a tributary of the Ohio River. Upper levels of the cave formed during a period of slow river incision and were later filled with sediment due to river aggradation at 2.3-2.4 Ma. A brief surge of river incision ca. 2 Ma was followed by river stability and cave-passage formation at a lower level. Rapid incision through 15 m of bedrock ca. 1.5 Ma was prompted by repositioning of the Ohio River to its present course along an ice-sheet margin. Renewed incision ca. 1.2 Ma and aggradation at 0.7-0.8 Ma correlate with major ice advances in the Ohio River basin. Measurements of 26Al and 10Be also indicate that sandstone-capped uplands have maintained slow erosion rates of 2-7 m/m.y. for the past 3.5 m.y., despite accelerated Pleistocene river incision rates of [~]30 m/m.y

Empirical and theoretical investigations of sculpted forms in Buckeye Creek Cave, West Virginia, 2002, Springer G. S. , Wohl E. E. ,
Sculpted forms play important roles in channel erosion, but the controls on their growth or appearance are uncertain. Empirical evidence from sculpted forms eroded into limestones within Buckeye Creek Cave, West Virginia, shows that types of sculpture morphology are determined by the types of flow or vortex structures present within sculptures during floods. Small hemispherical sculptures maintain constant form as they enlarge and occupy fixed locations on channel walls because of their association with joints, styolites, and bedding planes. Taking advantage of the systematic growth and stability of the sculptures, a geometrical model of sculpture growth is presented that relates the effects of sculpture size, form, and wall retreat to the relative erosion efficiencies and excesses required for sculpture growth. Numerical results obtained from the theoretical model reveal that small sculptures must erode more efficiently than large sculptures or they will be removed by wall retreat and that erosion rates must increase exponentially with increasing concavity. Relative to channel erosion, small sculptures must possess very high interior erosion rates where nearby surfaces are rapidly eroding. Therefore, small sculptures are unlikely to form or persist on rapidly eroding surfaces, and the rate of incision is an important control on the evolution of sculpted forms

Erosion Rates: Theoretical Models, 2004, Dreybrodt W.

Erosion Rates: Field Measurements, 2004, Gunn J.

Results 1 to 15 of 27
You probably didn't submit anything to search for