Significance and origin of very large regulating power of some karst aquifers in the Middle East. Implication on karst aquifer classification, , Elhakim M, Bakalowicz M,

SummaryKarst aquifers are the main groundwater resource in Lebanon as well as in most Mediterranean countries. Most of them are not exploited in a sustainable way, partly because their characteristics remain unknown. Karst aquifers are so complex that the assessment of their resource and their exploitable storage requires an analysis of their whole functioning, particularly by analysing the spring hydrograph. Among all various methods, the method proposed by Mangin aims to characterize at the same time the recharge conditions and the storage and recession of the saturated zone by analyzing the spring hydrograph. This method defines two parameters, the infiltration delay i, and the regulating power k which are the roots of a classification of karst systems. This classification makes the distinction between karst and porous aquifers considering the value of the regulating power. k is assumed to be lower than 0.5 in karst, and between 0.5 and 1 for all other aquifers, 1 being the upper limit.The study of karst aquifers in Lebanon shows values of k > 0.5, and even 1; former data from the literature show that other karst springs in Middle East have comparable characteristics. In fact, what is not considered by Mangin and others, k is equivalent to a mean residence time in years of water in the saturated zone. So long residence times are normally observed in poorly karstified aquifers, or containing abandoned, not functioning karstification. The geological framework in which the studied springs are located in fact shows that these aquifers have been subject to a long, complex evolution, as a consequence of the base level rising. This rising produced the flooding of the successive karst drainage network, which does not really function anymore and provides a large storage capacity to the aquifer. The very interesting properties of these aquifers make them prime targets for fulfilling the increasing needs of water

Controversy over the great flood hypotheses in the Black Sea in light of geological, paleontological, and archaeological evidence, , Yankohombach Valentina, Gilbert Allan S. , Dolukhanov Pavel,

Legends describing a Great Flood are found in the narratives of several world religions, and the biblical account of Noah's Flood is the surviving heir to several versions of the ancient Mesopotamian Flood Myth. Recently, the story of the biblical deluge was connected to the Black Sea, together with the suggestion that the story's pre-Mesopotamian origins might be found in the Pontic basin [Ryan, W.B.F., Pitman, III, W.C., 1998. Noah's Flood: The New Scientific Discoveries About the Event That Changed History. Simon and Schuster, New York]. Based on the significance of this flood epic in the Judeo-Christian tradition, popular interest surged following publication of the idea.Currently, two Great Flood scenarios have been proposed for the Black Sea: (1) an Early Holocene event caused by catastrophic Mediterranean inflow at 7.2 ky BP (initial hypothesis of [Ryan et al., 1997. An abrupt drowning of the Black Sea shelf. Marine Geology 138, 119-126]) or 8.4 ky BP (modified hypothesis of [Ryan et al., 2003. Catastrophic flooding of the Black Sea. Annual Review of Earth and Planetary Science 31, 525-554.); and (2) a Late Pleistocene event brought on by Caspian influx between 16 and 13 ky BP [Chepalyga, A.L., 2003. Late glacial Great Flood in the Black Sea and Caspian Sea. GSA Annual Meeting and Exposition, 2-5 November 2003, Seattle, USA, p. 460]. Both hypotheses claim that the massive inundations of the Black Sea basin and ensuing large-scale environmental changes had a profound impact on prehistoric human societies of the surrounding areas, and both propose that the event formed the basis for the biblical Great Flood legend.This paper attempts to determine whether the preponderance of existing evidence sustains support for these Great Floods in the evolution of the Black Sea. Based upon established geological and paleontological data, it finds that the Late Pleistocene inundation was intense and substantial whereas the Early Holocene sea-level rise was not. Between 16 and 13 ky BP, the Late Neoeuxinian lake (the Late Pleistocene water body in the Pontic basin pre-dating the Black Sea) increased rapidly from ~-14 to -50 m (below the present level of the Black Sea), then rose gradually to ~-20 m by about 11 ky BP. At 11-10 ky BP (the Younger Dryas), it dropped to ~-50 m. When the Black Sea re-connected with the Sea of Marmara at about 9.5 ky BP, inflowing Mediterranean water increased the Black Sea level very gradually up to ~-20 m, and in so doing, it raised the salinity of the basin and brought in the first wave of Mediterranean immigrants. These data indicate no major drawdown of the Black Sea after the Younger Dryas, and they do not provide evidence for any catastrophic flooding of the Black Sea in the Early Holocene.In addition, available archaeological and paleoenvironmental evidence from the Pontic region reveal no recognizable changes in population dynamics between 14 and 6 ky BP that could be linked to an inundation of large magnitude [Dolukhanov, P., Shilik, K., 2006. Environment, sea-level changes, and human migrations in the northern Pontic area during late Pleistocene and Holocene times. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 297-318; Stanko, V.N., 2006. Fluctuations in the level of the Black Sea and Mesolithic settlement of the northern Pontic area. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 371-385]. More specifically, Mesolithic and early Neolithic archaeological data in southeastern Europe and Ukraine give no indications of shifts in human subsistence or other behavior at the time of the proposed catastrophic flood in the Early Holocene [Anthony, D., 2006. Pontic-Caspian Mesolithic and Early Neolithic societies at the time of the Black Sea Flood: A small audience and small effects. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 345-370; Dergachev and Dolukhanov, 2006. The Neolithization of the North Pontic area and the Balkans in the context of the Black Sea Floods. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 489-514]

Recharge of Phreatic Aquifers in (Semi-)Arid Areas, ,

Groundwater use is of fundamental importance to meet the rapidly expanding urban, industrial and agricultural water requirements in (semi) arid areas. Quantifying the current rate of groundwater recharge and define its variability in space and time are thus prerequesites for efficient groundwater resource managment in these regions, where such resources are often the key to economic development. Attention focuses on recharge of phreatic aquifers, often the most readily-available and affordable source of water in (semi) arid regions. These aquifers are also the most susceptible to contamination, with the recharge rate determining their level of vulnerability. (Semi) arid zone recharge can be highly variable, the greater the aridity, the smaller and potentially more variable the natural flux. Its determination is an iterative process, involving progressive data collection and resource evaluation; there is also a need to use more than one technique to verify results. Direct, localised and indirect recharge mechanisms from a spectrum of known sources are addressed in the framework of recharge from precipitation, intermittant flow and permanent water bodies. The approach taken for each of these reflects the nature and current understanding of the processes involved. The volume also reviews current recharge estimation challenges, outlines recent developments and offers guidance for potential solutions.

A comparative integrated geophysical study of Horseshoe Chimney Cave, Colorado Bend State Park, Texas, , Brown Wesley A. , Stafford Kevin W. , Shawfaulkner Mindy , Grubbs Andy

An integrated geophysical study was performed over a known cave in Colorado Bend State Park (CBSP), Texas, where shallow karst features are common within the Ellenberger Limestone. Geophysical survey such as microgravity, ground penetrating radar (GPR), direct current (DC) resistivity, capacitively coupled (CC) resistivity, induced polarization (IP) and ground conductivity (GC) measurements were performed in an effort to distinguish which geophysical method worked most effectively and efficiently in detecting the presence of subsurface voids, caves and collapsed features. Horseshoe Chimney Cave (HCC), which is part of a larger network of cave systems, provides a good control environment for this research. A 50 x 50 meter grid, with 5 m spaced traverses was positioned around the entrance to HCC. Geophysical techniques listed above were used to collect geophysical data which were processed with the aid of commercial software packages. A traditional cave survey was conducted after geophysical data collection, to avoid any bias in initial data collection. The survey of the cave also provided ground truthing. Results indicate the microgravity followed by CC resistivity techniques worked most efficiently and were most cost effective, while the other methods showed varying levels of effectiveness.

Anomalous behaviour of specific electrical conductivity at a karst spring induced by variable catchment boundaries: the case of the Podstenjšek spring, Slovenia, , Ravbar, N. , Engelhardt, I. , Goldscheider, N.

Anomalous behaviour of specific electrical conductivity (SEC) was observed at a karst spring in Slovenia during 26 high-flow events in an 18-month monitoring period. A conceptual model explaining this anomalous SEC variability is presented and reproduced by numerical modelling, and the practical relevance for source protection zoning is discussed. After storm rainfall, discharge increases rapidly, which is typical for karst springs. SEC displays a first maximum during the rising limb of the spring hydrograph, followed by a minimum indicating the arrival of freshly infiltrated water, often confirmed by increased levels of total organic carbon (TOC). The anomalous behaviour starts after this SEC minimum, when SEC rises again and remains elevated during the entire high-flow period, typically 20–40 µS/cm above the baseflow value. This is explained by variable catchment boundaries: When the water level in the aquifer rises, the catchment expands, incorporating zones of groundwater with higher SEC, caused by higher unsaturated zone thickness and subtle lithologic changes. This conceptual model has been checked by numerical investigations. A generalized finite-difference model including high-conductivity cells representing the conduit network (“discrete-continuum approach”) was set up to simulate the observed behaviour of the karst system. The model reproduces the shifting groundwater divide and the nearly simultaneous increase of discharge and SEC during high-flow periods. The observed behaviour is relevant for groundwater source protection zoning, which requires reliable delineation of catchment areas. Anomalous behaviour of SEC can point to variable catchment boundaries that can be checked by tracer tests during different hydrologic conditions.

A New Equation Solver for Modeling Turbulent Flow in Coupled Matrix‐Conduit Flow Models, ,

Karst aquifers represent dual flow systems consisting of a highly conductive conduit system embedded in a less permeable rock matrix. Hybrid models iteratively coupling both flow systems generally consume much time, especially because of the nonlinearity of turbulent conduit flow. To reduce calculation times compared to those of existing approaches, a new iterative equation solver for the conduit system is developed based on an approximated Newton–Raphson expression and a Gauß–Seidel or successive over-relaxation scheme with a single iteration step at the innermost level. It is implemented and tested in the research code CAVE but should be easily adaptable to similar models such as the Conduit Flow Process for MODFLOW-2005. It substantially reduces the computational effort as demonstrated by steady-state benchmark scenarios as well as by transient karst genesis simulations. Water balance errors are found to be acceptable in most of the test cases. However, the performance and accuracy may deteriorate under unfavorable conditions such as sudden, strong changes of the flow field at some stages of the karst genesis simulations.

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Bermuda--A partially drowned, late mature, Pleistocene karst, 1960, Bretz Jh,

During Pleistocene time, the Bermuda Islands repeatedly underwent partial inundation and re-emergence. The land areas were continuously attacked and reduced by rain and ground water but repeatedly renewed, during times of submergence, by deposition of marine limestone and by contemporaneous additions of shore-born and wind-transported carbonate sand, now eolianite. Soils formed under subaerial conditions are now buried beneath later deposits and constitute important stratigraphic markers. The igneous foundation rock appears to have been exposed during some low marine stands, and the former shorelines seem to be recorded by submerged terraces. The major karst features are largely below sea level, and they must date from times of continental glaciations. Previous writers have assigned eolian accumulation to times of Pleistocene low sea level and soil-making to times of interglacial high sea. Both conclusions are held to be erroneous

Observations on Caves, Particularly Those Of South Australia - 1862 , 1962, Lane, Edward A.

The historical study of Australian caves and caving areas is fascinating although involving the expenditure of vast amounts of time. Australia's early days are unusually well-documented, but in the case of caves the early history is usually wrapped up in rumour, hearsay and clouded by lack of written record. Most research work means long hours poring over old newspaper files, mine reports, land department records and so on, little of which is catalogued. A small number of exploration journals and scientific studies have extensive material on special cave areas, and of these, the volume by Rev. Julian Edmund Woods, F.G.S., F.R.S.V., F.P.S., etc., and is one of the most interesting. This book gives the ideas and beliefs of 100 years ago concerning the origin, development and bone contents of caves and makes interesting reading in the light of more recent studies of cave origins. Wood's study "Geological Observations in South Australia : Principally in the District South-East of Adelaide" was published in 1862 by Longman, Green, Roberts and Green, London. In a preface dated November 15, 1861, Rev. Woods points out that the book was written while he was serving as a missionary in a 22,000 square mile district, and "without the benefit of reference, museum, library, or scientific men closer than England". Up to the time of writing, almost no scientific or geological work had been done in South Australia and much of the area was completely unexplored. The book, also, contained the first detailed description of caves in the south-east of the state. Father Woods writes about many different types of caves in South Australia, for instance, the "native wells" in the Mt. Gambier/Mt. Shanck area. These are caves, rounded like pipes, and generally leading to water level. Woods points out their likeness to artificial wells. He also writes of sea cliff caves, particularly in the Guichen Bay area, and blow holes caused by the action of the waves on the limestone cliffs. Woods discusses many other types of caves found further inland, particularly bone caves. Father Woods discusses cave origins under two sub-heads: 1. Trap rock caves generally resulting from violent igneous action, and 2. Limestone caves resulting from infiltration of some kind. He is mainly concerned with limestone caves which he sub-divides into (a) crevice caves - caves which have arisen from fissures in the rock and are therefore wedge-shaped crevices, widest at the opening, (b) sea-beach caves, caves which face the seashore and are merely holes that have been worn by the dashing of the sea on the face of the cliff, (c) egress caves, or passages to give egress to subterranean streams, (d) ingress caves, or passages caused by water flowing into the holes of rocks and disappearing underground. These caves would have entrance holes in the ground, opening very wide underneath, and having the appearance of water having entered from above, (e) finally a group of caves which he lists by use as "dens of animals".

Morphology of New Zealand Limestone Caves , 1963, Laird, M. G.

Limestone caves in New Zealand can be divided into two distinct groups : those developed in the nearby flat-lying limestone of Oligocene age, and those formed in the strongly folded Mt. Arthur Marble of Upper Ordovician age. Caves formed in Oligocene limestone are typically horizontal in development, often having passages at several levels, and are frequently of considerable length. Those formed in Mt. Arthur Marble have mainly vertical development, some reaching a depth of several hundred feet. Previous research into the formation and geological history of New Zealand cave systems is discussed briefly, and the need for further work is emphasised.

The Discovery, Exploration and Scientific Investigation of the Wellington Caves, New South Wales, 1963, Lane Edward A. , Richards Aola M.

Although research has been unable to establish a definite date of discovery for the limestone caves at Wellington, New South Wales, documentary evidence has placed it as 1828. The actual discovery could have been made earlier by soldiers or convicts from the Wellington Settlement, which dated from 1823. Whether the aborigines knew of the cave's existence before 1828 is uncertain, but likely, as in 1830 they referred to them as "Mulwang". A number of very small limestone caves were also discovered about the same time in the nearby Molong area. The Bungonia Caves, in the Marulan district near Goulburn, were first written about a short time later. On all the evidence available at present, the Wellington Caves can be considered to be the first of any size discovered on the mainland of Australia. The Wellington Caves are situated in a low, limestone outcrop about six miles south by road from the present town of Wellington, and approximately 190 miles west-north-west of Sydney. They are at an altitude of 1000 feet, about half a mile from the present bed of the Bell River, a tributary of the Macquarie River. One large cave and several small caves exist in the outcrop, and range in size from simple shafts to passages 200 to 300 feet long. Mining for phosphate has been carried out, resulting in extensive galleries, often unstable, at several levels. Two caves have been lit by electricity for the tourist trades; the Cathedral Cave, 400 feet long, maximum width 100 feet, and up to 50 feet high; and the smaller Gaden Cave. The Cathedral Cave contains what is believed to be the largest stalagmite in the world, "The Altar", which stands on a flat floor, is 100 feet round the base and almost touches the roof about 40 feet above. It appears that the name Cathedral was not applied to the cave until this century. The original names were "The Great Cave", "The Large Cave" or "The Main Cave". The Altar was named by Thomas Mitchell in 1830. See map of cave and Plate. Extensive Pleistocene bone deposits - a veritable mine of bone fragments - were found in 1830, and have been studied by palaeontologists almost continually ever since. These bone deposits introduced to the world the extinct marsupials of Australia, and have a special importance in view of the peculiar features of the living fauna of the continent. The names of many famous explorers and scientists are associated with this history, among the most prominent being Sir Thomas Mitchell and Sir Richard Owen. Anderson (1933) gives a brief outline of why the Wellington Caves fossil bone beds so rapidly attracted world-wide interest. During the 18th and early 19th Century, the great palaeontologist, Baron Georges Cuvier, and others, supposed that the earth had suffered a series of catastrophic changes in prehistoric times. As a result of each of these, the animals living in a certain area were destroyed, the area being repopulated from isolated portions of the earth that had escaped the catastrophe. The Bilical Deluge was believed to have been the most recent. Darwin, during the voyage of the Beagle around the world (1832-37), was struck by the abundance of Pleistocene mammalian fossils in South America, and also by the fact that, while these differed from living forms, and were in part of gigantic dimensions, they were closely related to present-day forms in that continent. Darwin's theory of descent with modification did not reconcile with the ideas of Cuvier and others. As the living mammalian fauna of Australia was even more distinctive than that of South America, it was a matter of importance and excitement to discover the nature of the mammals which had lived in Australia in the late Tertiary and Pleistocene.

Corrosion by mixing of waters., 1964, Bogli Alfred

Karst caves are prior to all due to corrosion. According to the well-known formula a CO2 supply is always needed. This type of dissolution explains only the corrosion in free circulation and, under reserve, the one in pressure conducts in the vadose zone. All corrosion in the phreatic domain is excluded, except for some rare cases in the upper levels. The corrosion by mixing of waters of different content in bicarbonates is effective in the entire karst, from the lowermost to the uppermost parts. Also the corrosion due to the lowering of temperature and by mixing of waters at different temperature has to be take into account. Excpet for some exceptional cases (e.g. thermal waters), this effect is very reduced.

Observations on the evolution of caves., 1964, Cavaille Albert

In this note, which results from a paper published in France, the author defines the "karst system" formed by several successive levels, at the heart of a limestone mass: joints of surface feeding, vertical chimneys, galleries which are alternatively dry and full of water according to the season, a network of continually drowned clefts. He then studies modifications in this system resulting from internal causes, corrosion, filling and sedimentation, concretion. Then he shows how this evolution of the karst system may be modified by general conditions: geology, tectonics, geography with the losses, resurgences and the role of surface formations. The deepening of the river level may create a structure of differing levels in the various karst system, but their positioning is always slower than the streams erosion and it comes about later. In any case, the caves in a dried karst system undergo an evolution on their own. Finally, the author gives the definition of the terms used to explain the evolution in the karst system: "embryonic galleries" in the network of clefts, "young galleries" in the zone which is alternately wet and dry, "mature galleries" where the concretion and the erosion are balanced, "old galleries" where the concretion is becoming more and more important, "dead galleries" where the cave is completely filled by the deposits and concretions. This classification will easily replace the inexact terms of "active galleries" and "fossilized galleries" which are too vague and lead to confusion.

Observations on the Eastern Horse-Shoe Bat in North-Eastern New South Wales , 1966, Dwyer, P. D.

Between July, 1960, and December, 1963, observations were made on the natural history of Rhinolophus megaphyllus Gray in north-eastern New South Wales. Typically the species occurs as small colonies in a wide variety of cave and mine roosts. It appears to be absent from available roosting sites at higher altitudes in this area. Seasonal changes in the sizes of testes and epididymides suggest that mating occurs in May and June. The single young are born at maternity colonies through November, and nursing lasts about eight weeks. Field weights do not reflect seasonal variation other than that associated with pregnancy. However, seasonal differences in daytime level of activity are noted and these correlate with behavioural changes apparently related to temperature selection. Changes in colony size are described for several roosts and three movements made by marked individuals are recorded. Males appear to be more sedentary than females. Considerable aggregation of females and their young at maternity colonies (size, 15 to 1,5000 individuals) characterises the spring and summer population.

Murray Cave, Cooleman Plain, New South Wales, 1966, Jennings, J. N.

Murray Cave is an almost horizontal former outflow cave, which is now on the brink of inactivity. A heavily decorated upper branch functioned during the first outflow phase and the present inactive entrance succeeded it as the outlet point. Both are at the level of a low aggradational terrace of the North Branch of Cave Creek outside the cave; this probably belongs to a Pleistocene cold period. An undecorated lower branch provided the third phase outlet, which still functions occasionally when water rises up a water trap at the inner end of the main passage and flows along that passage into it. The entrance chamber has angular gravel fill due to frost shattering, which post-dates the development of the lower branch passage and belongs to a late Pleistocene cold period. Evidence of free surface stream action predominates in the cave but shallow phreatic conditions must have contributed to its development.

Underground solution canyons in the Central Kentucky karst, U.S.A., 1967, Watson Richard A.

Solution canyons are underground voids 1 to 15 + meters wide, 3 to 45 + meters high, and 30 to 300 + meters long. Floors are stepped, ceilings level. Size increases downstream. Their course is sinuous, with some angularity. They occur parallel to and directly under or slightly offset from the thalwegs of re-entrant valleys tributary to major karst valleys. A section across a re-entrant and underlying solution canyon shows a rough hour-glass shape. Solution canyons are related genetically to solutional vertical shafts, forming where removal of the impermeable sandstone caprock permits the vertical descent of water through jointed limestone. Surface runoff concentrates along re-entrant thalwegs where a largo quantity of water goes underground. This water, plus subsurface water flowing over the caprock breached by the valleys, follows the easiest route to baselevel down major vertical joints oriented parallel to the thalwegs. Solution by water seeping down these joint planes forms solution canyons.