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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. ...

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 chimney is 1. nearly circular shaft rising upwards from the ceiling of a cave towards the surface of the ground; if it does not reach the surface it is termed a blind chimney. if the chimney is formed mainly by solution, it is related to a domepit; if formed mainly by collapse of the roof along bedding planes, it is related to cenote [20]. 2. a narrow vertical shaft in the roof of a cave, generally smaller than an aven; a dome pit [10]. synonyms: (french.) cheminee (aven); (german.) schlot, kamin; (greek.) kapnothochos; (italian.) camino; (russian.) truba; (spanish.) chimenea; (turkish.) baca; (yugoslavian.) dimnjak.?

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


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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
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 removal (Keyword) returned 84 results for the whole karstbase:
Showing 61 to 75 of 84
Phreatic drainage conduits within quartz sandstone: Evidence from the Jurassic Precipice Sandstone, Carnarvon Range, Queensland, Australia, 2009,
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Wray R.

Discrete underground drainage conduits in quartz sandstones are far less common than in limestones. This paper provides field evidence from the quartzose Precipice Sandstone in the Carnarvon Range of south-central Queensland, Australia, for tubular underground drainage networks similar in many ways to limestone conduits. Diameters range from less than 1 or 2 cm to over 1.5 m, most display a near-circular to oval cross-section that seems to suggest phreatic or epiphreatic development, and the internal surfaces of many are case-hardened by secondary silica deposits. A number of the region's perennial springs appear to be fed by such tubes. The dominant vertical jointing of the quartz sandstone and relatively high permeability of the sandstone are important controls on tube formation. Solutional weathering of the sandstone is widespread, and is followed by the removal of loosened sand grains by flowing underground water, the process of ‘arenisation’. Tube development would appear to have been happening for a very long time, and may still be occurring. A model for tube network formation is proposed. These findings highlight our potentially poor understanding of groundwater flow within some quartz sandstones, and may have important groundwater management implications.


HYPOGENE CAVES IN THE APENNINES (ITALY), 2009,
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Galdenzi S.

In the Apennine Mountains many examples of hypogene caves are known, generally related to present or past rise of sulfidic water that, mixing with oxygenated water of shallow flow systems, causes the sulfuric acid dissolution of limestone. The hypogene caves are generally located in small limestone outcrops covered by rocks of low permeability that in?uence the groundwater flowpaths. Some caves, however, are known also in hydrogeological massifs, where epigenic caves prevail. The hypogene caves show different patterns, ranging from phreatic to pure water table caves. The former prevail when karst evolved below the water table in structures almost completely covered by low permeability units; the latter occur in zones where a fast recharge of freshwater can reach the sulfidic water from the karst surface. The progressive lowering, thinning and removal of the low-permeability covers by non-karstic erosion processes can cause the progressive evolution from phreatic to water table caves. Active speleogenetic processes due to H2 S oxidation can be directly observed in different hydrogeologic settings: in highly permeable aquifers with ready recharge of freshwater (Frasassi caves), in thermal caves, below low permeability cover (Acquasanta Terme), or in marine thermal caves with salt water intrusion (Capo Palinuro).


An external model of speleogenesis during Quaternary glacial cycles in the marbles of central Scandinavia, 2010,
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Faulkner, T.

The marble caves of the Central Scandinavian Caledonides were formed from open fractures that were created primarily by deglacial seismicity at the culmination of each of the many complex Quaternary glaciations that the region has experienced. Subsequent inundation by deglacial ice-dammed lakes enabled phreatic enlargement by dissolution, with passages either becoming relict during the following interglacial or else being entrenched by (mainly) vadose processes if recharged by allogenic streams. Because the distance of the contemporary fractures and therefore the cave passages from the nearest land surface is commonly constrained to be less than one-eighth of the depth of the local glaciated valley, the caves are rather epigean in nature. This subsurface cave distance is of the same order of magnitude as the thickness of rock removed from valley walls and floors at each major glaciation, suggesting that, when viewed over several glacial cycles, caves are involved in a race to develop deeper during deglaciation and the following interglacial before their upper levels are removed by erosion at the next glaciation. Indeed, relatively few cave passages in the study area can have survived from the previous, Eemian, interglacial.
This paper examines evidence for the interglacial and erosional processes and utilises a 'black box' approach to provide an external model for cave development and removal. It proposes that Caledonide marble caves in stripe karst outcrops should especially be considered as four-dimensional objects throughout their commonly intermittent existence. Mainly vadose caves are regarded as 'half-cycle' caves that developed primarily in the Holocene. Relict caves (primarily phreatic) and combination caves (with both phreatic and vadose elements) are commonly 'single-cycle' caves that developed their relict phreatic passages during Weichselian deglaciation, and only a few are 'multi-cycle' caves that have experienced several Pleistocene glacial cycles. The existing caves are more numerous and commonly larger than those that were present during previous interglacials.


Geomorphologische Untersuchung und genetische Interpretation der Dachstein- Mammuthhle (sterreich), 2010,
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Plan L. , Xaver A.
The speleogenesis of Dachstein-Mammuthhle, the third-longest cave system in the Northern Calcareous Alps, has been discussed controversially in the past. Using morphologic mapping and morphometric data of the central parts of the cave in combination with modern speleogenetic models a re-evaluation of its development is attempted. The geometry of the cave and several small-scale features (e.g., scallops, karren, ceiling meanders), which date back to the early history of the cave formation, lead to the following interpretion: old phreatic parts (galleries, mazes, and some pits) developed under epiphreatic conditions during flood events, followed by younger, vadose canyon-shaft-systems. Scallops and sedimentary structures indicate a general westward flow direction. Sediments played an important role during the formation of the profiles, i.e. the profiles expanded upward (paragenesis) because the floor of the galleries was sealed by sediments, and only part of the cross section, as it can be seen today after removal of these sediments, was occupied by water. This is relevant for calculations of the palaeodischarge from mean scallop lengths and cross-section areas. Paragenesis can only be ruled out for the origin of the keyhole profile of the so-called Canyon (near the Westeingang) and the palaeodischarge was estimated to 16 m/s. This, however, was probably only a fraction of the total discharge of this system as several additional large galleries occur at the same cave level. The former catchment area was probably located south of todays Northern Calcareous Alps

Bell Hole Origin: Constraints on Developmental Mechanisms, Crooked Island, Bahamas, 2011,
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Birmingham Andrew N. , Mylroie Joan R. , Mylroie John E. , Lace Michael J.

Bell holes are vertical, cylindrical voids, higher than they are wide, with circular cross sections and smooth walls found in the ceilings of dissolutional caves primarily from tropical and subtropical settings. They range in size from centimeter to meters in height and width. The origin of bell holes has been controversial, with two proposed categories: vadose mechanisms including bat activity, condensation corrosion, and vadose percolation; and phreatic mechanisms including degassing and density convection.
Crooked Island, Bahamas has a number of caves with bell holes of unusual morphology (up to 7 m high and 1.5 m in diameter), commonly in tight clusters, requiring significant bedrock removal in a small area. In many cases, numerous bell holes are open to the surface, which requires that up to a meter or more of surface denudation has occurred since the bell hole first formed.
Surface intersection has little impact on the phreatic mechanisms, which were time limited to cave genesis from 119 to 131 ka ago, but greatly reduces the time window for later vadose mechanisms, which need to have been completed before bell hole intersection by surface denudation.
The Crooked Island observations suggest that bell hole development occurred syngenetically with flank margin cave development under phreatic conditions. Because flank margin caves develop under slow flow conditions, vertical convection cell processes are not disrupted by turbulent lateral flow and bell holes formed as a vertical phreatic dissolution signature.


On the formation of collapse dolines: A modelling perspective, 2011,
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Gabrovš, Ek Franci, Stepiš, Nik Uroš,

Collapse dolines are among the most striking surface features in karst areas. Although they can be the result of different formation mechanisms, evidence suggests that large collapse dolines form due to chemical and mechanical removal of material at and below the level of groundwater. We have applied a genetic model of a two-dimensional fracture network to calculate the rate of dissolutional bedrock removal in the heavily fractured (crushed) zone intersecting a karst conduit in the phreatic zone. To account for infilling and breakdown processes in the crushed zone two simple rules were added to the basic model: 1) continuous infilling of dissolutionally created voids prevents fractures from growing beyond some limited aperture, although the dissolution proceeds, 2) discontinuous collapsing causes sudden closure of a fracture once some critical aperture has been reached. Both rules limit the transmissivity of the network and the related flow rates. Therefore, the constant head difference between the input and the output points is sustained and the flow remains distributed over the entire crushed zone. Provided that restrictions posed by the two rules permit turbulent flow, dissolution rates also remain high in the entire region. High surface area of water–rock contact and high dissolution rates result in high overall removal rates of rock from the crushed zone, one of the necessary conditions for the formation of large closed depressions. Despite the fact that the model neglects some processes and dynamics that would increase the removal rate, the results suggest that large closed depressions could form in the order of 1 million years.


Modified DRASTIC assessment for intrinsic vulnerability mapping of karst aquifers: a case study , 2011,
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Mimi Ziad A. , Mahmoud Nidal, Abu Madi Maher

Groundwater in karstic aquifers can be dangerously sensitive to contamination. In this paper, DRASTIC assessment was modified and applied, for the first time, to address the intrinsic vulnerability for karst aquifers. The theoretical weights of two of DRASTIC’s parameters (aquifer media and hydraulic conductivity) were modified through sensitivity analysis. Two tests of sensitivity analyses were carried out: the map removal and the single parameter sensitivity analyses. The modified assessment was applied for the karst aquifers underlying Ramallah District (Palestine) as a case study. The aquifer vulnerability map indicated that the case study area is under low, moderate and high vulnerability of groundwater to contamination. The vulnerability index can assist in the implementation of groundwater management strategies to prevent degradation of groundwater quality. The modified DRASTIC assessment has proven to be effective because it is relatively straightforward, use data that are commonly available or estimated and produces an end product that is easily interpreted.


Tenglong Dong and the caves of Lichuan County, Hubei, China, 2011,
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Campion, Gerard

Tenglong Dong is a spectacular cave system in Lichuan County in China's Hubei Province. Currently it is one of the longest caves in China, and it contains some notably large passages. It lies within an impressive karst landscape that includes imposing cave entrances, dolines, tiankengs, natural arches and poljes. Members of the British China Caves Project have been assisting staff from the Institute of Karst Research (in Guilin), the Research Institute of Tourism development, China University of Geosciences, and the Government of Hubei Province in trying to achieve Geopark status for the area that includes and surrounds Tenglong Dong. The cave system includes extensive high-level relict passages, which contain a fascinating show cave, and an active river passage, which has proved challenging to navigate. Taken as a whole, the system would form an impressive centre piece for a Geopark in Lichuan. As with many caves in China, the caves in Lichuan have suffered generations of speleothem removal that has resulted in locally extensive damage to a fragile environment. This continuing problem will present a serious challenge to those involved in cave conservation for the area.


Ascending speleogenesis of Sokola Hill: a step towards a speleogenetic model of the Polish Jura, 2011,
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Gradziń, Ski M. , Hercman H. , Kiciń, Ska D. , Pura D. , Urban J.

The paper deals with the origin of caves in Sokola Hill (Polish Jura). the caves abound in solution cavities in the walls and ceilings, many of them arranged hierarchically, some others arranged in rising sets. blind chimneys and ceiling half-tubes are also present. these features collectively indicate that the caves originated under phreatic conditions by an ascending flow of water, probably of elevated temperature. Phreatic calcite spar, crystallized from water of elevated temperature, lines the cave walls. during the formation of the caves the Jurassic limestone aquifer was confined by impermeable cover. three possible scenarios for the origin of the caves are suggested. the first scenario points to formation of the caves during the Palaeogene prior to the removal of the confining cretaceous marls. the second connects the origin of the caves with regional palaeoflow driven by tectonic loading by carpathian nappes to the south, while the third refers to local topographically driven palaeoflow. both the second and third scenarios assume that the Polish Jura had a cover of Miocene impermeable clastics. All the scenarios account for the origin of the caves in Sokola Hill and explain the common occurrence of ascending caves throughout the Polish Jura.

In the subsequent stages of evolution the caves were partly filled with various deposits. conglomerates composed of Jurassic limestone clasts, quartz sands and sandstones are preserved as erosional remnants, locally covered by or interfingered with calcite flowstones. the clastic deposits were laid down by surface streams that invaded the caves earlier than 1.2 Ma. the caves were not invaded by water from Pleistocene glaciers, which is proved by the assemblage of heavy minerals in the cave clastics.


GHOST-ROCK STRUCTURES AND THE NATURE OF AZ CAVES, 2011,
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Quinif, Yves

Because of the presence of wall and roof cupolas and other microforms indicative of differential weathering, we first of all considered the genesis of the Azé caves, following the usual concept of karstogenesis, as a phreatic formation. A second stage is a vadose evolution associated with the underground river. But the time relationship between the two caves presents a problem because
the deposits in the Aiglons gallery demonstrate a river evolution during the last glaciation. Today, we know that many karstic systems begin their genesis by a process of ghost-rock formation. The discovery of the “Galerie de Chauffailles” proves this origin, because the speleologists have removed not river sediments, but the residual alterite in a “pseudoendokarst”. Some stratigraphic sequences of
the bedrock in the prehistoric gallery can be seen as residual alterite: the “ghost-rock” in the “Galerie de Chauffailles”. The genesis of the Azé caves began by a ghost-rock phase giving a pseudoendokarstic system consisting of weathered interconnected cavities. This residual alterite is made up of less minus soluble minerals like silica cherts, clay minerals and sparitic calcite. It is very fragile and porous. The second stage consists in the mechanical removal of the residual alterite by an underground river. A very interesting characteristic of the Azé cave is that we can study the contact between the river sediments of the second stage and the residual alterit  of the first stage.

A cause de la présence de formes pariétales de type coupoles et microformes de corrosion différentielle, on a longtemps considéré la genèse de grottes telles celles d’Azé comme issue de conditions phréatiques, dans le contexte de la karstogenèse par évacuation totale. Une deuxième étape comprend une évolution vadose de type fluviatile. Mais les relations temporelles entre les deux grottes d’Azé posent un problème. Les dépôts fluviatiles de la Galerie des Aiglons démontrent qu’il a existé une circulation fluviatile durant la dernière glaciation. Cette constatation permet d’envisager une genèse de type fantôme de roche, pour laquelle cette question d’évolution ne constitue plus un problème. La découverte de la Galerie de Chauffailles prouve ce type de spéléogenèse. En effet, la désobstruction de cette galerie ne s’est pas faite dans les sédiments fluviatiles, mais pour une bonne part en retirant l’altérite résiduelle demeurée dans un pseudoendokarst. La genèse de la Grotte d’Azé commence ainsi par une altération in situ générant un système de pseudoendokarsts consistant en volumes altérés interconnectés. L’altérite résiduelle est composée des minéraux insolubles ou moins solubles comme les chailles, la calcite sparitique, les minéraux argileux. Ce milieu est fragile et très poreux. La
seconde étape évolutive est l’érosion mécanique partielle de cette altérite résiduelle par les rivières souterraines. Une caractéristique très intéressante de la grotte d’Azé est qu’il y est possible d’étudier le contact entre l’altérite résiduelle et les sédiments fluviatiles.


Post-speleogenetic biogenic modification of Gomantong Caves, Sabah, Borneo , 2012,
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Lundberg J, Mcfarlane D. A.

The Gomantong cave system of eastern Sabah, Malaysia, is well-known as an important site for harvesting edible bird-nests and, more recently, as a tourist attraction. Although the biology of the Gomantong system has been repeatedly studied, very little attention has been given to the geomorphology. Here, we report on the impact of geobiological modification in the development of the modern aspect of the cave, an important but little recognized feature of tropical caves. Basic modeling of the metabolic outputs from bats and birds (CO2, H2O, heat) reveals that post-speleogenetic biogenic corrosion can erode bedrock by between ~ 3.0 mm/ka (1 m/~300 ka) and ~ 4.6 mm/ka (1 m/~200 ka). Modeling at high densities of bats yields rates of corrosion of ~ 34 mm/ka (or 1 m/~30 ka). Sub-aerial corrosion creates a previously undescribed speleological feature, the apse-flute, which is semicircular in cross-section and ~ 80 cm wide. It is vertical regardless of rock properties, developing in parallel but apparently completely independently, and often unbroken from roof to floor. They end at a blind hemi-spherical top with no extraneous water source. Half-dome ceiling conch pockets are remnants of previous apse-fluting. Sub-cutaneous corrosion creates the floor-level guano notch formed by organic acid dissolution of bedrock in contact with guano. Speleogenetic assessment suggests that as much as 70–95% of the total volume of the modern cave may have been opened by direct subaerial biogenic dissolution and biogenically-induced collapse, and by sub-cutaneous removal of limestone, over a timescale of 1–2 Ma.


Preparing the ground - new mechanisms for karst and speleogenesis: 'alteration', fantomisation and replacement, 2012,
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Laverty, Martin

Two distinctive new rock alteration mechanisms that can lead to the development of karst features, including caves, are reviewed here for the first time in a British publication. Fantomisation is a two-stage process of partial dissolution around fractures followed, typically much later, by rapid removal of the residue to create passages. Replacement is the simultaneous volume-for-volume alteration of the mineralogy of the rock to create apparently buried forms in situ. These new explanations are not restricted to development of karst in carbonates, and can explain otherwise enigmatic features. They should be considered when interpreting the history, hydrology and morphology of caves and karst where the host rock has been in a low-energy environment with surface and/or fractures open enough for ingress of weathering fluid at some time since its deposition.


The nature and origin of the ghost-rocks at Bullslaughter Bay, South Wales, 2012,
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Rowberry Matt D. , Battiauqueney Yvonne, Blazejowski Blazej, Walsh Peter

The ‘ghost-rocks’ of the British Isles have attracted very little research interest over the years despite being widely distributed. In South Wales, the ghost-rocks of the Pembroke Peninsula are usually associated with the mudrock formations immediately above and below the Carboniferous Limestone. This study focuses on their nature and origin through a detailed investigation of the cliff sections at Bullslaughter Bay. The investigated ghost-rocks are associated with a suite of breccias, collectively termed the Gash Breccias. These are an enigmatic suite of around twenty-five large breccia masses located exclusively in the eastern part of the peninsula. They comprise huge masses of coarse, chaotic, clast-supported, monomictic breccia and represent highly disturbed features in the otherwise unbroken sequences of Carboniferous Limestone. Their origin may be karstic, tectonic, or a combination of the two. They could, theoretically, have formed at any point between the end of the Carboniferous and the Pliocene. If their origin is karstic, it cannot yet be determined if the processes were attributable to per descensum or per ascensum groundwater systems. If tectonic, it is not known whether they formed during periods of compression or extension. From our own geological and geophysical fieldwork, we believe that the breccias originated as a result of subterranean karstic processes whilst retaining an open mind with regard to the role played by tectonics. The breccia and ghost-rocks are both displayed in fine cliff exposures around Bullslaughter Bay. These sections, although not extensive, are extremely instructive. The processes that generate ghost-rock result in isovolumetric weathering of the host rock and an associated loss of density and strength. They may or may not involve the removal of certain chemical constituents in the regolith through solution and hydrolysis followed by the formation of secondary minerals, frequently clay. In reality, the precise weathering process differs according to the type of rock. The process is controlled by the permeability of each rock type in banded rocks such as mudstones or shale with banded chert whereas it is controlled by fissures and faults in homogenous rocks. This control is clearly seen in the Carboniferous Limestone around Bullslaughter Bay, where ghost-rocks are present, more commonly in case of impure or dolomitic limestone. At present, it is not clear whether the groundwater movements were caused by hydrothermal or meteoric processes and this forms the basis of ongoing research. Finally, the study considers the relationship that exists between the ghost-rock and the Gash Breccia. We examine whether there is a logical correlation between the processes that came to generate the ghost-rock and the processes responsible for the generation of the breccia. It may then be possible to accurately state whether the ghost-rock formed before, during, or after, the breccia. The reasons that the ghost-rocks of the British Isles have attracted very little research interest may stem from the fact that they have no current commercial value, have seldom presented engineering problems, and are normally difficult to date. It is clear that numerous karst related sag-subsidences in the British Isles result from the large-scale decalcification of the Carboniferous Limestone (e.g. the Tortonian Brassington Formation of the southern Pennines). There is, however, an increasingly large body of evidence to suggest that these subsidences result from the same processes that generate ghost-rock rather than those that create endokarstic voids. The subsidences may preserve stratigraphical sequences several decametres thick and reach depths and widths of many hectometres. Unfortunately, the masses of decalcified limestone below the Tortonian sediments are of no commercial interest and have hardly ever been penetrated by boreholes. Therefore, we do not know exactly what underlies the karstic fills. The possibility that most of these structures are best explained as the result of per ascensum groundwater flow is discussed.


Denudation and Erosion Rates in Karst, 2013,
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Gunn, J.

In many lithologies erosion (removal of material) and denudation (lowering of the land surface) are directly related butthis is not the case in karst where the majority of erosion is subsurface and only contributes to denudation over geological time. Dissolution is the dominant agent of both denudation and erosion although mechanical weathering of karst rock by clasts brought in by allogenic streams may contribute to the enlargement of cave passages. Most published ‘denudation’rates are actually corrosion rates and many were based on at most a few years of spot measurements at a spring or at a catchment outlet. Hence, considerable caution is necessary in interpreting the results. Cosmogenic nuclides could provide loner-term denudation estimates but have only rarely been applied to karst. Theoretical equations allow prediction of maximum erosion rates from runoff (water surplus), temperature, and carbon dioxide concentrations but field measurements indicate that erosion rarely operates at the maximal rate. Erosion rates vary spatially, with dolines a clear focus, and vertically, with most dissolution contributing to development of the epikarst rather than direct lowering of the land surface. Human activities, and particularly limestone quarrying, are potent erosive forces and in some areas more limestone was removed by quarrying in the twentieth century than by corrosion over the Holocene. Quarrying is also a direct agent of denudation, locally lowering land surface by tens or hundreds of meters


High Resolution Seismic Reflection Methods to Detect Near Surface Tuff-Cavities: A Case Study in the Neapolitan Area, Italy, 2013,
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Di Firoe V. , Angelino A. , Passaro S. , Bonanno A.

 

The Neapolitan region of Italy is plagued by the presence of shallow manmade cavities in lithoid tuffs that cause problems for communities because they produce building damages and loss of human lives. A high resolution P-wave seismic-reflection technique was successfully used to define a cavity 6 m by 10 m in horizontal dimensions and with a height of about 6 m located in a tuff layer 10 to 19 m below ground level. Such a cavity was located at Afragola (near Naples) where the local geology is typical of the Neapolitan area. The seismic dataset was acquired by using end-on spread geometry, with 0.25 m spacing for shots and 0.5 m for receivers. The application of band–pass filtering (30–150 Hz) allowed us to remove incoherent noise from the data, while an additional equivalent slope (Vs21) of 0.005 s m21 cut in the FK transform results in ground-roll noise removal. Both the acquisition and processing methods have been necessary to investigate and define the shape and dimensions of the targeted cavity


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