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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. ...

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. ...

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That basin mouth is the point at which runoff leaves a basin [16].?

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Your search for pit caves (Keyword) returned 8 results for the whole karstbase:
GEOLOGY AND KARST GEOMORPHOLOGY OF SAN-SALVADOR ISLAND, BAHAMAS, 1995, Mylroie J. E. , Carew J. L. ,
The exposed carbonates of the Bahamas consist of late Quaternary limestones that were deposited during glacio-eustatic highstands of sea level. Each highstand event produced transgressive-phase, stillstand-phase, and regressive-phase units. Because of slow platform subsidence, Pleistocene carbonates deposited on highstands prior to the last interglacial (oxygen isotope substage 5e, circa 125,000 years ago) are represented solely by eolianites. The Owl's Hole Formation comprises these eolianites, which are generally fossiliferous pelsparites. The deposits of the last interglacial form the Grotto Beach Formation, and contain a complete sequence of subtidal intertidal and eolian carbonates. These deposits are predominantly oolitic. Holocene deposits are represented by the Rice Bay Formation, which consists of intertidal and eolian pelsparites deposited during the transgressive-phase and stillstand-phase of the current sea-level highstand. The three formations are separated from one another by well-developed terra-rossa paleosols or other erosion surfaces that formed predominantly during intervening sea-level lowstands. The karst landforms of San Salvador consist of karren, depressions, caves, and blue holes. Karren are small-scale dissolutional etchings on exposed and soil-covered bedrock that grade downward into the epikarst, the system of tubes and holes that drain the bedrock surface. Depressions are constructional features, such as swales between eolian ridges, but they have been dissolutionally maintained. Pit caves are vertical voids in the vadose zone that link the epikarst to the water table. Flank margin caves are horizontal voids that formed in the distal margin of a past fresh-water lens; whereas banana holes are horizontal voids that developed at the top of a past fresh-water lens, landward of the lens margin. Lake drains are conduits that connect some flooded depressions to the sea. Blue holes are flooded vertical shafts, of polygenetic origin, that may lead into caves systems at depth. The paleokarst of San Salvador is represented by flank margin caves and banana holes formed in a past fresh-water lens elevated by the last interglacial sea-level highstand, and by epikarst buried under paleosols formed during sea-level lowstands. Both carbonate deposition and its subsequent karstification is controlled by glacio-eustatic sea-level position. On San Salvador, the geographic isolation of the island, its small size, and the rapidity of past sea level changes have placed major constraints on the production of the paleokarst

Speleogenesis in coastal and oceanic settings, 2000, Mylroie J. E. , Carew J. L.
Carbonate islands and coasts are directly influenced by the chemistry of mixing marine and fresh water, and by the migration of sea level in response to Quaternary glacio-eustasy. Carbonate islands are unique in particular because they are limited in recharge to their own areal extent, whereas carbonate coasts can obtain recharge from adjacent, non-carbonate areas. Carbonate islands fall into three categories: Simple carbonate islands which are entirely carbonate from the land surface to a depth exceeding the lowest Quaternary glacio-eustatic sea-level lowstand (approximately -125 m); carbonate-cover islands which are entirely carbonate, but a carbonate/non-carbonate contact exists within the range of Quaternary glacio-eustasy; and carbonate-rimmed islands where non-carbonate rocks are present at the surface. Simple carbonate islands have only autogenic recharge and develop pit caves in the epikarst, banana holes at the top of the fresh-water lens, and flank margin caves at the margin of the freshwater lens. Carbonate-cover islands develop additional caves at the carbonate/non-carbonate contact, and carbonate-rimmed islands form stream caves from non-carbonate allogenic recharge. Blue holes and large conduit caves exist on carbonate islands and coasts. They are overprinted by Quaternary glacio-eustasy, and their development is linked to processes not operating at their locations today.

Karst development on carbonate islands, 2003, Mylroie J. E. , Carew J. L.

Karst development on carbonate platforms occurs continuously on emergent portions of the platform. Surficial karst processes produce an irregular pitted and etched surface, or epikarst. The karst surface becomes mantled with soil, which may eventually result in the production of a resistant micritic paleosol. The epikarst transmits surface water into vadose pit caves, which in turn deliver their water to a diffuse-flow aquifer. These pit caves form within a 100,000 yr time frame. On islands with a relatively thin carbonate cover over insoluble rock, vadose flow perched at the contact of carbonate rock with insoluble rock results in the lateral growth of vadose voids along the contact, creating large collapse chambers that may later stope to the surface.
Carbonate islands record successive sequences of paleosols (platform emergence) and carbonate sedimentation (platform submergence). The appropriate interpretation of paleosols as past exposure surfaces is difficult, because carbonate deposition is not distributed uniformly, paleosol material is commonly transported into vadose and phreatic voids at depth, and micritized horizons similar in appearance to paleosols can develop within existing carbonates.
On carbonate islands, large dissolution voids called flank margin caves form preferentially in the discharging margin of the freshwater lens from the effects that result from fresh-water/salt-water mixing. Similarly, smaller dissolution voids also develop at the top of the lens where vadose and phreatic fresh-waters mix. Independent of fluid mixing, oxidation of organic carbon and oxidation/reduction reactions involving sulfur can produce acids that play an important role in phreatic dissolution. This enhanced dissolution can produce caves in fresh-water lenses of very small size in less than 15,000 yr. Because dissolution voids develop at discrete horizons, they provide evidence of past sea-level positions. The glacio-eustatic sea-level changes of the Quaternary have overprinted the dissolutional record of many carbonate islands with multiple episodes of vadose, fresh-water phreatic, mixing zone, and marine phreatic conditions. This record is further complicated by collapse of caves, which produces upwardly prograding voids whose current position does not correlate with past sea level positions.
The location and type of porosity development on emergent carbonate platforms depends on the degree of platform exposure, climate, carbonate lithology, and rate of sea-level change. Slow, steady, partial transgression or regression will result in migration of the site of phreatic void production as the fresh-water lens changes elevation and moves laterally in response to sea-level change. The result can be a continuum of voids that may later lead to development solution-collapse breccias over an extended area.


Late Pleistocene-Holocene sea-level rise and the pattern of coastal karst inundation: records from submerged speleothems along the Eastern Adriatic Coast (Croatia), 2005, Suric Masa, Juracic Mladen, Horvatincic Nada, Krajcar Bronic Ines,
In order to reconstruct the late Pleistocene-Holocene sea-level rise along the Eastern Adriatic Coast, eight speleothems were collected from three submerged caves along the Croatian coast from depths of -38.5 to -17 m. The marine biogenic overgrowth layer and the youngest and the oldest parts of the speleothems were dated by the 14C method. Their stable isotope (13C/12C and 18O/16O) contents were also measured. From the measured 14C activity of the marine overgrowth and using the model of Alessio et al. (1992, Risultati preliminari relativi alla datazione di speleotemi sommersi nelle fasce costiere del Tirreno centrale. Giornale di Geologia ser. 3 54/2, 165-193), the start of overgrowth (i.e., the time of flooding by seawater) was determined to be 10,185 cal BP at -36 m, 9160 cal BP at -34 m, and 7920 cal BP at -23 m.Our results partially match the sea-level curves reconstructed for adjacent areas (Tyrrhenian Coast and French Mediterranean Coast). However, the start of the marine overgrowth on speleothems in pit caves indicates strong dependence on the steepness of the terrain. On steep, extensively karstified coasts, marine overgrowths on speleothems coincided with the submersion of the speleothems due to the relatively short distance between the pit and the open sea and fast penetration of seawater into the pit. In contrast, marine overgrowths on speleothems in pits in the flat terrains occurred later because speleothem growth ceased due to flooding with fresh groundwater. Later, the fresh water was replaced by seawater due to the greater distance of the inland pits to the former coast

Hoga island, Sulawesi, Indonesia: geomorphology and groundwater resources of a small tropical carbonate island, 2006, Dykes A. P. , Gunn J.
This paper provides the first report of the geomorphology and hydrogeology of Hoga island, a small tropical carbonate island in southeast Sulawesi, Indonesia, based on reconnaissance field explorations and surveys. Hoga is being developed as a specialist ecotourism destination, and a sustainable water supply is one of the important development issues. The island comprises 3.42km2 of low-lying hard, but highly karstified, coral limestone covered with dense scrub forest and coconut plantations. It displays dissolution features typical of similar tropical islands, including pit caves and flank margin caves. A freshwater aquifer exists with a water table 1.57m above MSL near the centre of the less karstified western two-thirds of the island, where surface elevations locally exceed 6m above MSL. All occurrences of potable freshwater, i.e. having electrical conductivity < 1500 mS cm-1, are also within this main part of the island. Complex hydrogeological conditions are indicated by the patterns of tidal influences on water levels in existing wells and natural dissolution holes. Using published studies and empirical relationships, it is estimated that Hoga contains a potable freshwater lens at least 2m thick (total volume c.300,000m3) and that annual recharge may exceed 500,000m3. As actual annual demand for freshwater since 2001 was < 2800m3, it is concluded that Hoga contains an aquifer that could sustain the present and likely future freshwater demands of residents and seasonal ecotourist populations, subject to satisfactory water quality assessment and management.

The Caves of Abaco Island, Bahamas: keys to geologic timelines, 2008, Walker L. N. , Mylroie J. E. , Walker A. D. , Mylroie J. R.

Abaco Island, located on Little Bahama Bank, is the most northeastern island in the Bahamian archipelago. Abaco exhibits typical carbonate island karst features such as karren, blue holes, pit caves, banana holes and flank margin caves. Landforms that resemble tropical cone karst and pseudokarst tafoni caves are also present. The three cave types of Abaco—flank margin caves, pit caves, and tafoni caves—are abundant, but each forms by very different mechanisms. Flank margin caves are hypogenic in origin, forming due to mixing dissolution at the margin of the freshwater lens. Since the lens margin is concordant with sea level, flank margin caves record the position of sea level during their formation. Flank margin caves exhibit phreatic dissolutional features such as bell holes, dissolutional cusps and spongework. Pit caves form as vadose fast-flow routes to the freshwater lens and are common on the Pleistocene eolianite ridges of the Bahamas. Pit caves are characterized by their near-vertical or stair-step profiles. Because pit caves form in the vadose zone, their position is not tied to sea level. Tafoni caves are pseudokarst features that form when the soft interior of an eolianite ridge is exposed to subaerial erosion. Since tafoni caves form by mechanical processes, they do not exhibit phreatic dissolutional features. Tafoni caves may be mistaken as flank margin caves by the untrained observer, which may cause problems when using caves as sea-level indicators. Each of Abaco’s unique cave types may preserve depositional and erosional features that are useful to the researcher in creating general geologic timelines. While these timelines may not give exact dates, they are useful in the field for understanding depositional boundaries and determining sequences of geologic events.


Pit cave morphologies in eolianites: variability in primary structure control, 2011, Moore Paul J. , Seale L. Don, Mylroie John E.

The landforms of San Salvador, Bahamas, demonstrate extensive karst development, in particular epikarst features called pit caves. Studies on Hog Cay, an interior dune ridge located north of the San Salvador International Airport runway, indicate that some pit caves have morphologies controlled by bedding. These pit caves, initiating within the vadose zone, have a tendency to follow the foreset beds of the dune for some distance and are analogous to solution chimneys found in continental settings. These solution chimneys are distinguished from vertical shafts, which propagate vertically into the vadose zone of the
subsurface with little, if any, horizontal offset.

Previous field observations have described how eolian deposits can be sorted by grain size into alternating coarse-grained and fine-grained strata. The alternating strata undergo selective cementation, where the coarse-grained strata become poorlycemented and the fine-grained strata become well-cemented because of retention of pore waters. This is observed in weathered outcrops as poorly-cemented micro-recesses and well-cemented micro-ledges. In the subsurface, the coarse-grained, poorlycemented strata are the preferred flow path for vadose water. This water is perched upon and flows laterally along the foreset beds on the well-cemented, fine-grained strata. Pit caves forming under these conditions are described as solution chimneys. Also found on Hog Cay are pit caves that extend from the surface down to near sea level. These vertical shafts are generally found on the crests of dunes, with the deepest shaft being over 15 meters. They commonly display a near-perfect cylindrical shape and extend vertically with no horizontal offset. The walls of vertical shafts exhibit micro-ledge and micro-recess morphology; however, the vertical shafts have no indication of bedding control, which may be due to cementation in the fine-grained layers
being less complete in certain areas, facilitating vertical shaft development.

Preliminary XRD analysis of the pit caves shows that the top and bottom wall rocks of one pit is almost entirely calcite, but the wall rocks in the middle of the pit have a high aragonite content. These observations are consistent with long residence time of meteoric water in the epikarst at the top of the pits, and in the fill material at the base of the pits, such that aragonite was inverted to calcite. However, the rapid transit time of the vadose water along the pit walls allowed dissolution to enlarge the pit, but without inversion of the primary aragonite.


HYPOGENE LIMESTONE CAVES IN GERMANY: GEOCHEMICAL BACKGROUND AND REGIONALITY, 2014, Kempe, S.

Germany exhibits a very diverse geological history. Thus, a large number of stratigraphically, petrographically and tectonically different carbonate and sulfate rocks exist that have been subject to karstification. Here, I discuss first the possible “agents” (sensu Klimchouk) of hypogene karstification. Three principally different processes are identified: water rising because of buoyancy (either thermally or concentration induced), in-situ oxidation of siderite, or rising gases (CO2, CH4 or H2S). Next, a rough overview of German caves and karst is presented. If applying the most pertinent epigene versus hypogene morphological characteristics, it becomes evident that hypogene caves occur in many different areas, often side-by-side with clearly epigene caves. For many areas, the agents of hypogene speleogenesis must remain unclear. This applies for most caves in the Paleozoic limestones of the Rhenish Schist Massif. Only the Iberg/Harz caves seem to be a clear case, with the world-wide highest concentrations of siderite weathering-induced caves occur. The large cavities discovered recently in the Blauhöhlen System and some of the deep pit caves in the Swabian Alb may have their explanation in volcanic CO2, having emanated from some of the 355 pipes of the Swabian volcanic field. Most striking is the high concentration of hypogene caves in the Franconian Alb. Many of them occur in a small area while other areas are devoid of larger caves. Here the tectonic situation suggests that fractures could have taped reservoirs of either sulfide or methane from below. The finding of goethitic crusts in the Bismarckgrotte may indicate that rising anaerobic gases could have been involved


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