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 LNAPL is abbreviation for light nonaqueous phase liquid. liquids falling into this category have specific gravities that are less than water (the specific gravity for water is usually taken to be one), are relatively immiscible with water, and tend to migrate downwards through the vadose and to float on top of the water table. see also lnapl; immiscible; napl.?

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 negev desert (Keyword) returned 5 results for the whole karstbase:
Paleoclimate and location of the border between Mediterranean climate region and the Saharo-Arabian Desert as revealed by speleothems from the northern Negev Desert, Israel, , Vaks A. , Barmatthews M. , Ayalon A. , Matthews A. , Frumkin A. , Dayan U. , Halicz L. , Mogilabin A. , Schilman B. ,
Speleothem bearing karstic caves of the northern Negev Desert, southern Israel, provides an ideal site for reconstructing the paleoclimate and paleo-location of the border between Mediterranean climate region and the Saharo-Arabian Desert. Major periods of speleothem deposition (representing humid periods) were determined by high resolution 230Th-U dating and corresponding studies of stable isotope composition were used to identify the source of rainfall during humid periods and the vegetation type. Major humid intervals occurred during glacials at 190-150[no-break space]ka, 76-25[no-break space]ka, 23-13[no-break space]ka and interglacials at 200-190[no-break space]ka, 137-123[no-break space]ka and 84-77[no-break space]ka. The dominant rainfall source was the Eastern Mediterranean Sea, with a possible small contribution from southern tropical sources during the interglacial periods. When the interglacial interval rainfall was of Eastern Mediterranean origin, the minimum annual rainfall was ~ 300-350[no-break space]mm; approximately twice than of the present-day. Lower minimum amounts of precipitation could have occurred during glacial periods, due to the cooler temperatures and reduced evaporation. Although during most of the humid periods the vegetation remained steppe with mixed C3 C4 vegetation, Mediterranean C3 type steppe-forest vegetation invaded southward for short periods, and the climate in the northern Negev became closer to Mediterranean type than at present. The climate was similar to present, or even more arid, during intervals when speleothem deposition did not occur: 150-144[no-break space]ka, 141-140[no-break space]ka, 117-96[no-break space]ka, 92-85[no-break space]ka, 25-23[no-break space]ka, and 13[no-break space]ka-present-day.Precipitation increase occurred in the northern Negev during the interglacial monsoonal intensity maxima at 198[no-break space]ka, 127[no-break space]ka, 83[no-break space]ka and glacial monsoonal maxima at 176[no-break space]ka, 151[no-break space]ka, 61[no-break space]ka and 33[no-break space]ka. However, during interglacial monsoonal maxima at 105[no-break space]ka and 11[no-break space]ka, the northern Negev was arid whereas during glacial monsoonal minima it was usually humid. This implies that there is not always synchroneity between monsoonal activity and humidity in the region.Oxygen isotopic values of the northern Negev speleothems are systematically lower than contemporaneous speleothems of central and northern Israel. This part is attributed to the increased rainout of the heavy isotopes by Rayleigh fractionation processes, possibly due to the farther distance from the Mediterranean coast

Karst and caves of Israel, 2001, Frumkin, A.
Israel displays a gradient of karst features from the intensive karstification of Lebanon in the north to practically no karst in Elat region at the southern Negev desert (Gerson, 1976). This is attributed mainly to the climatological gradient from alpine-Mediterranean climate in the Lebanon - Hermon mountains in the north, with precipitation >1000 mm/year, to the extremely arid southern Negev, with <50 mm/year. Another factor is the southward decrease in carbonates/clastics ratio of the phanerozoic stratigraphic section, due to the increasing distance from the Tethys Sea which deposited the significant carbonates. Carbonate rocks outcrop in some 75% of the hilly regions of Israel. They are predominantly of Jurassic to Eocene age. However, much of the carbonates contain marls which inhibit extensive karst development, promoting the dominance of fluviokarst features. Another inhibiting factor is the abundance of faults in the Hermon, Galil and Shomeron regions. The faults are thought to constrain the temporal and spatial continuous underground flow, limiting the development of large caves in these regions. Most limestone caves are relict phreatic conduits and voids, which do not show any genetic relation to subaerial topography. Today these caves are either dry or experience vadose dripwater. These caves have possibly developed under moister conditions than predominate today. Some of them have been sealed from the surface until opened by recent construction activity. They may contain valuable paleoclimatic records (Frumkin, et al., 1994). Vadose caves are also common, and typically experience some water flow and active dissolution during the rainy season. These are mostly composed of vertical shafts with rare horizontal sections. The unique rock salt karst of Mount Sedom exhibits the largest salt caves known in the world. Some sea caves, attributed mainly to wave action with limited dissolution appear in the 'Kurkar' sandstone ridge along the Mediterranean coast. Paleokarst is common in the stratigraphic section, and is probably related to humid paleoclimates. Israel is especially rich in man made caves sustaining abundant fauna, but are beyond the scope of this review.

Paleoclimate and location of the border between Mediterranean climate region and the Saharo?Arabian Desert as revealed by speleothems from the northern Negev Desert, Israel, 2006, Vaks, A. , Barmatthews, M. , Ayalon, A. , Matthews, A. , Frumkin, A. , Dayan, U. , Halicz, L. , Almogilabin, A. , And Schilman, B.
Speleothem bearing karstic caves of the northern Negev Desert, southern Israel, provides an ideal site for reconstructing the paleoclimate and paleo-location of the border between Mediterranean climate region and the Saharo?Arabian Desert. Major periods of speleothem deposition (representing humid periods) were determined by high resolution 230Th?U dating and corresponding studies of stable isotope compositionwere used to identify the source of rainfall during humid periods and the vegetation type.Major humid intervals occurred during glacials at 190?150 ka, 76?25 ka, 23?13 ka and interglacials at 200?190 ka, 137?123 ka and 84?77 ka. The dominant rainfall sourcewas the EasternMediterranean Sea, with a possible small contribution from southern tropical sources during the interglacial periods. When the interglacial interval rainfall was of Eastern Mediterranean origin, the minimum annual rainfall was ∼300?350 mm; approximately twice than of the present-day. Lowerminimum amounts of precipitation could have occurred during glacial periods, due to the cooler temperatures and reduced evaporation. Although during most of the humid periods the vegetation remained steppe withmixed C3+C4 vegetation,Mediterranean C3 type steppe-forest vegetation invaded southward for short periods, and the climate in the northern Negev became closer toMediterranean type than at present. The climate was similar to present, or even more arid, during intervals when speleothem deposition did not occur: 150?144 ka, 141?140 ka, 117?96 ka, 92?85 ka, 25?23 ka, and 13 ka?present-day. Precipitation increase occurred in the northern Negev during the interglacial monsoonal intensity maxima at 198 ka, 127 ka, 83 ka and glacial monsoonal maxima at 176 ka, 151 ka, 61 ka and 33 ka. However, during interglacial monsoonal maxima at 105 ka and 11 ka, the northern Negev was arid whereas during glacial monsoonal minima it was usually humid. This implies that there is not always synchroneity between monsoonal activity and humidity in the region. Oxygen isotopic values of the northern Negev speleothems are systematically lower than contemporaneous speleothems of central and northern Israel. This part is attributed to the increased rainout of the heavy isotopes byRayleigh fractionation processes, possibly due to the farther distance from the Mediterranean coast.

Desert speleothems reveal climatic window for African exodus of early modern humans, 2007, Vaks, A. , Barmatthews, M. , Ayalon, A. , Matthews, A. , Halicz, L. And Frumkin, A.
One of the first movements of early modern humans out of Africa occurred 130?100 thousand years ago (ka), when they migrated northward to the Levant region. The climatic conditions that accompanied this migration are still under debate. Using high-precision multicollector?inductively coupled plasma?mass spectrometry (MC-ICP-MS) U-Th methods, we dated carbonate cave deposits (speleothems) from the central and southern Negev Desert of Israel, located at the northeastern margin of the Saharan-Arabian Desert. Speleothems grow only when rainwater enters the unsaturated zone, and this study reveals that a major cluster of wet episodes (the last recorded in the area) occurred between 140 and 110 ka. This episodic wet period coincided with increased monsoonal precipitation in the southern parts of the Saharan- Arabian Desert. The disappearance at this time of the desert barrier between central Africa and the Levant, and particularly in the Sinai-Negev land bridge between Africa and Asia, would have created a climatic ?window? for early modern human dispersion to the Levant.

Middle-Late Quaternary paleoclimate of northern margins of the Saharan-Arabian Desert: reconstruction from speleothems of Negev Desert, Israel, 2010, Vaks Anton, Barmatthews Miryam, Matthews Alan, Ayalon Avner, Frumkin Amos

Speleothems in arid and hyper-arid areas of Negev Desert, Israel, are used in paleoclimate reconstruction of northern margins of Saharan-Arabian Desert, focused on the following objectives: 1) precise U–Th dating of the timing of speleothem growth as an indicator of periods of humid climate, i.e. positive effective precipitation; 2) the origin of rainfall using the speleothem δ18O and changes in spatial pattern of speleothem deposition and speleothem thickness along a north–south transect; 3) changes of vegetation cover based on speleothem δ13C variations.

During the last 350 ka major humid periods, referred to herein as Negev Humid Periods (NHP), occurred in the central and southern Negev Desert at 350–310 ka (NHP-4), 310–290 ka (NHP-3), 220–190 ka (NHP-2), and 142–109 ka (NHP-1). NHP-4, NHP-2 and NHP-1 are interglacial events, whereas NHP-3 is associated with a glacial period. During NHP-1, 2 and 3 the thickness and volume of the speleothems decrease from the north to the south, and in the most southern part of the region only a very thin flowstone layer formed during NHP-1, with no speleothem deposition occurring during NHP-2 and 3. These data imply that the Eastern Mediterranean Sea was the major source of the rainfall in northern and central Negev. More negative speleothem δ18O values, relative to central parts of Israel (Soreq Cave) are attributed to Rayleigh distillation because of the increasing distance from the Mediterranean Sea. Speleothem deposition during the NHP-4 in the southern Negev was more intensive than in most of the central Negev, suggesting the prominence of the tropical rain source.

Decrease in speleothem δ13C during NHP events indicates growth of the vegetation cover. Nevertheless, the ranges of δ13C values show that the vegetation remained semi-desert C4 type throughout the NHPs, with an additional significant carbon fraction coming from the host rock and the atmosphere. These observations, together with small thickness of the speleothem layers, favor that NHP events consisted of clusters of very short humid episodes interspersed with long droughts.

NHP events were contemporaneous with climate periods with monsoon index of ≥51 (cal/cm2 × day) and with the formation of sapropel layers in the Mediterranean Sea. Such simultaneous intensification of the monsoon and Atlantic-Mediterranean cyclones is probably related to the weakening of the high pressure cell above sub-tropical Atlantic Ocean, which enabled more rainfall to penetrate into the Saharan-Arabian Desert from the north and south. The contemporaneous occurrence of the NHP events and the increased monsoon rainfall could have opened migration corridors, creating climatic “windows of opportunity” for dispersals of hominids and animals out of the African continent.


Results 1 to 5 of 5
You probably didn't submit anything to search for