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Enviroscan Ukrainian Institute of Speleology and Karstology

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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. ...

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 obsequent river is a river flowing in a direction opposite to that of the dip of the underlying strata [16].?

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

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KarstBase a bibliography database in karst and cave science.

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 submarine (Keyword) returned 65 results for the whole karstbase:
Showing 31 to 45 of 65
Deep water circulation, residence time, and chemistry in a karst complex, 2003,
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Aquilina L, Ladouche B, Doerfliger N, Bakalowicz M,
We investigated the hydrochemistry of a complex karst hydrosystem made of two carbonate units along a coastal lagoon. Ground water emerges on the lagoon floor from a submarine spring. In addition, thermal waters circulate through the limestone and mix with karst water near the lagoon shore. A distinction between the water from the two carbonate units is related to marine influences and human activities. In one of the massifs, the data show an incongruent dissolution of dolomite with time. In the other system, a slight contamination by saline fluids from the thermal reservoir has led to high calcium and magnesium concentrations. Cl-36, C-14, and H-3 data constrain the residence time of the water, and allow for the distinguishing of four circulation types: (1) shallow surface circulation (primarily above sea level) in the karstic units with short residence times (<20 years); (2) shallow subsurface circulation (approximately 0 to -50 in) below the karstic units with residence time in the order of 50 years; (3) deep circulation at depth of 700 to 1500 m in the Jurassic limestones below thick sedimentary cover, with residence time of several thousand years for a part of the water; and (4) deep circulation at a depth of similar to2500 in, which represents the thermal reservoir in the Jurassic units with residence time of similar to100,000 years. An interpretative hydrogeological framework is based on the constraints of the geochemical analyses of the deep thermal system. and by water flow from the surface to the deep parts of the carbonate formations

Regional Quaternary submarine geomorphology in the Florida Keys, 2003,
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Lidz Barbara H. , Reich Christopher D. , Shinn Eugene A. ,
High-quality seismic reflection profiles fill a major gap in geophysical data along the south Florida shelf, allowing updated interpretations of the history of the Quaternary coral reef system. Incorporation of the new and existing data sets provides the basis for detailed color maps of the Pleistocene surface and thickness of overlying Holocene accretions. The maps cover the Florida Keys to a margin-wide upper-slope terrace (30 to 40 m deep) and extend from The Elbow Reef (north Key Largo) to Rebecca Shoal (Gulf of Mexico). The data indicate that Pleistocene bedrock is several meters deeper to the southwest than to the north east, yet in general, Holocene sediments are [~]3 to 4 m thick shelf-wide. The Pleistocene map demonstrates the significance of a westward-dipping bedrock surface to Holocene flooding history and coral reef evolution. Seismic facies show evidence for two possible Holocene stillstands. Aerial photographs provide information on the seabed surface, much of which is below seismic resolution. The photographs define a prominent, regional nearshore rock ledge that extends [~]2.5 km seaward from the keys' shoreline. They show that bands of rock ridges exist along the outer shelf and on the upper-slope terrace. The photographs also reveal four tracts of outlier reefs on the terrace, one more than had been documented seismically. Seismic and photographic data indicate the tracts are >200 km long, nearly four times longer than previously thought. New interpretations provide insights into a youngest possible terrace age (ca. 175 ka?) and the likelihood that precise ages of oxygen isotope substage 5e ooid tidal-bar and coral reef components may differ. The tidal-bar/reef complex forms the Florida Keys

The origine and evolution of coastal and submarine springs in Bakar Bay, 2003,
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Benac Č, Edomir, Rubinić, Josip, Ož, Anić, Nevenka

The paper presents coastal and submarine springs in Bakar Bay. The northeastern coast of Bakar Bay is abound in springs, since there is the lowest placed contact between large karst aquifer and flysch lithogenetic complex which forms hydrogeological barrier. Studied area is situated between rno and Žminjca locations, where water flows out in series of concentrated coastal and submarine springs as well as on the places of a diffuse outflow. A rapid raise of sea-level from the end of the Pleistocene changed the hydrogeological conditions so that coastal springs were submerged and new ones, at higher levels appeared. Some of submerged springs continued to throw out water, that is, they started to function as submarine springs (vrulja) due to a strong inflow from the background and high pressures. Some of them were not registered, although according to water balance analyses of wider area, widespread evidences of groundwater outflow could be expected. Their position reflects geological fabric of the area. Groundwaters have intensive flowing gradient. Their flowing out in hydraulically unstable zone have facilitated mixing of sea- water and fresh-water and as a result spring-water is usually brackish.

Geophysical evidence for karst formation associated with offshore groundwater transport: An example from North Carolina, 2003,
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Evans Rob L. , Lizarralde Dan

Marine geophysical data from Long Bay, North Carolina, involving a novel combination of electromagnetic and high-resolution Chirp seismics, show evidence of submarine karst formation associated with what has been inferred to be a site of high-flux submarine groundwater discharge (SGD) a substantial distance offshore. Recently observed temperature and chemical signals from wells in this area provide the basis for the interpretation of the high-flux SGD here, and they also suggest a terrestrial source for the groundwater and thus a potentially important route for nutrient transport to the oceans. Our data indicate that karstification is localized to the high-flux zone, and we suggest that mixing of the chemically distinct (but saline) groundwater with seawater has resulted in the karstification. As karstification increases permeability and flux, a positive feedback would tend to progressively enhance submarine groundwater discharge. Our data reveal a significant local anomaly in apparent porosity: a dense block that may have initiated the local focusing of groundwater flow. Conditions favorable to the formation of similar locally punctuated sites of high-flux SGD are likely to exist along the mid to inner shelf of the southeastern United States, where carbonate aquifers are prevalent

Prehistory and coastal karst area: Cosquer Cave and the Calanques of Marseille, 2004,
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Collinagirard, J.

The Cosquer Cave is a French Palaeolithic painted and engraved cave (27.000-18.500 BP), which is located under the sea, in the Urgonian limestones of Cap Morgiou (“Massif des Calanques”, Marseille). The entrance was submerged at the end of the Last Glacial Stage and is presently 37 m under sea level. A synthesis about the Cosquer Cave environmental studies is presented here. Structural studies show that caves planimetry is determined by Cap Morgiou jointing (mainly NW-SE and N-S vertical faults). Through archaeological studies, a speleothem breaking period can be dated between 27.000 and 18.000 BP. Geomorphologic study of the continental shelf at the foot of the Cosquer Cave area shows fossil shorelines at -36 m, -50/55 m, -90 m, -100 m depth. Radiocarbon dating from shells collected in -100m sediments yielded a date of 13.250 BP. Direct scuba diving observations and submarine cliff profiles sketching show several eustatic still stand¬ levels between -36m and the current sea surface indicating a probable tectonic stability during the last 10.000 years.

The effect of the Messinian Deep Stage on karst development around the Mediterranean Sea. Examples from Southern France, 2004,
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Audra P, Mocochain L, Camus H, Gilli E, Clauzon G, Bigot Jy,
It is difficult to explain the position and behaviour of the main karst springs of southern France without calling on a drop in the water table below those encountered at the lowest levels of Pleistocene glacio-eustatic fluctuations. The principal karst features around the Mediterranean are probably inherited from the Messinian period ('Salinity crisis') when sea level dropped dramatically due to the closing of the Straight of Gibraltar and desiccation of the Mediterranean Sea. Important deep karst systems were formed because the regional ground water dropped and the main valleys were entrenched as canyons. Sea level rise during the Pliocene caused sedimentation in the Messinian canyons and water, under a low hydraulic head, entered the upper cave levels. The powerful submarine spring of Port-Miou is located south of Marseille in a drowned canyon of the Calanques massif. The main water flow comes from a vertical shaft that extends to a depth of more than 147 in bsl. The close shelf margin comprises a submarine karst plateau cut by a deep canyon whose bottom reaches 1,000 in bsl. The canyon ends upstream in a pocket valley without relation to any important continental valley. This canyon was probably excavated by the underground paleoriver of Port-Miou during the Messinian Salinity Crisis. Currently, seawater mixes with karst water at depth. The crisis also affected inland karst aquifers. The famous spring of Fontaine de Vaucluse was explored by a ROV (remote observation vehicle) to a depth of 308 in, 224 m below current sea level. Flutes observed on the wall of the shaft indicate the spring was formerly an air-filled shaft connected to a deep underground river flowing towards a deep valley. Outcroppings and seismic data confirm the presence of deep paleo-valleys filled with Pliocene sediments in the current Rhone and Durance valleys. In the Ardeche, several vauclusian springs may also be related to the Messinian Rhone canyon, located at about 200 in below present sea level. A Pliocene base level rise resulted in horizontal dry cave levels. In the hinterland of Gulf of Lion, the Cevennes karst margin was drained toward the hydrologic window opened by the Messinian erosional surface on the continental shelf

Origin of Meter-Scale Submarine Cavities and Herringbone Calcite Cement in a Cambrian Microbial Reef, Ledger Formation (U.S.A.), 2004,
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De Wet Cb, Frey Hm, Gaswirth Sb, Mora Ci, Rahnis M, Bruno Cr,
Meter-scale submarine cavities in Middle Cambrian shelf-margin microbial reef strata indicate large-scale dewatering processes, in conjunction with substrate instability related to interreef channeling and shelf-edge downslope creep and slip. Syndepositional cement precipitation within the cavities preserved delicate microbial fabrics and stabilized the reef system. Radiaxial fibrous calcite and herringbone calcite cements line the cavity interiors isopachously. The two phases cannot be discriminated on the basis of Fe, Mn, or Sr contents, but do have different isotopic signatures. Slightly more negative {delta}13C values in herringbone calcite suggest that abrupt transitions between radiaxial fibrous and herringbone calcite cement are the result of rapid and repeated changes in pore-fluid oxygen levels. Storm-driven pore-water circulation renewed oxygenated seawater flow into the cavities, resulting in precipitation of radiaxial fibrous calcite. A threshold level of oxygen reduction resulted in the change to herringbone calcite precipitation. The pore fluids associated with herringbone calcite did not have elevated Mn or Fe concentrations, as suggested in previous studies. Herringbone calcite appears to be more susceptible to diagenetic alteration than radiaxial fibrous cement however, as indicated by greater resetting of oxygen isotope values

The Danube submarine canyon (Black Sea): morphology and sedimentary processes, 2004,
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Popescu Irina, Lericolais Gilles, Panin Nicolae, Normand Alain, Dinu Cornel, Le Drezen Eliane,
The Danube Canyon is a large shelf-indenting canyon that has developed seaward of the late Pleistocene paleo-Danube valley. Mechanisms of canyon evolution and factors that controlled it are revealed by analyzing the morphology and the sedimentary structure of the canyon, as well as the main features of the continental margin around the canyon. This is based on investigation by swath bathymetry in the canyon area combined with different types of seismic data.The canyon is a major erosional trough with a flat bottom cut by an entrenched axial thalweg. The thalweg path varies from highly meandering to fairly straight in relation to the local gradient. Segments of the canyon are characterized by specific morphology, orientation and gradient along the axial thalweg. We interpret these segments in terms of canyon maturity. The sedimentary structure of the canyon documents an older phase of erosion followed by partial infilling, and thus attests for repeated cycles of canyon development.Canyon morphology is interpreted as a result of erosive sediment flows along the entrenched axial thalweg that caused downcutting into the canyon bottom and instability of the canyon walls, and hence enlargement of the canyon and expansion by headward erosion. During the last lowstand level of the Black Sea the canyon was located in an area of high sediment supply close to the paleo-Danube River mouths. This is indicated by buried fluvial channels on the shelf and by a wave-cut terrace associated with a water level situated about -90 m below the present level. We infer that erosive flows in the canyon resulted from hyperpycnal currents at the river mouths, probably favored by the low salinity environment that characterized the Black Sea during lowstand times. Other mechanisms could have contributed to trigger sediment failure along the canyon, such as instability related to the presence of shallow gas, or the effect of a deep fault

Sequence Biostratigraphy of Prograding Clinoforms, Northern Carnarvon Basin, Western Australia: A Proxy for Variations in Oligocene to Pliocene Global Sea Level?, 2004,
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Moss Graham D. , Cathro Donna L. , Austin James A. Jr. ,
Sequence biostratigraphic analyses from five industry wells in the Northern Carnarvon Basin (NCB), Western Australia, are tied to seismic stratigraphic interpretations from a set of 3D and 2D seismic data. Distribution patterns of [~]286 benthic and 73 planktonic foraminiferal taxa in sidewall cores and ditch cuttings from Eocene to Pliocene intervals are documented and supplemented with observations of other fossil groups (e.g., fragments of ostracodes, bryozoans, corals, and mollusks) and lithological components such as calcite cement and quartz sand. Preservation of foraminiferal assemblages is extremely variable in latest Eocene to Pliocene stratigraphy, depending upon the location of wells and the interval investigated. Nonetheless, consistent, detectable faunal signals correlate between wells and with prominent seismic horizons and sequences. The late Oligocene to middle Miocene is characterized by deeper-water benthic assemblages dominated by infaunal taxa and a high planktonic abundance. Stratigraphic events in the middle Miocene, including turnover in benthic foraminifera, are interpreted to record a regional flooding event (equivalent to cycle Tejas B (TB) 2.3) at the beginning of the mid-Miocene climatic optimum ([~]16-14.5 Ma). Following this event, seismically defined geomorphic features include karstification on the shelf and incision on the clinoform front. All wells show a major transition to shallow-water, warm conditions on the shelf in the middle and late Miocene, with benthic assemblages dominated by larger foraminifera. This transition appears higher in more-basinward wells and appears to be a result of progradation. Geomorphic features in the late middle Miocene ([~]12 Ma) identified from 3D seismic analyses show an intensification of earlier gully formation, resulting in the development of submarine canyons. Detailed analyses of faunal patterns also provide evidence of higher-frequency sea-level fluctuations (0.5-3 Ma), not detected in the seismic stratigraphic patterns

Characterizing a coastal karst aquifer using an inverse modeling approach: The saline springs of Thau, southern France, 2004,
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Pinault J. L. , Doerfliger N. , Ladouche B. , Bakalowicz M. ,
[1] A methodological approach using inverse modeling was used to characterize the functioning of the deep and shallow reservoirs of the Thau karst aquifer system. Three springs were monitored at the convergence of rising saline water diluted with shallow groundwater in karst conduits and unmixed shallow groundwater that behaves as confined groundwater. In such a method, impulse responses of flow and fluxes are combined in order to separate hydrographs. The model explains the salinity and hydraulic head variations of the submarine and inland springs. It confirms and improves the conceptual model of this groundwater system in which mixing of saline and subsurface waters occurs. The different forces driving the upward flowing mixed water into the drainage axis and faults were studied in order to elucidate the springs' functioning. A comparative study of spring functioning is proposed, which clearly shows the very high sensitivity of the groundwater system to changes in recharge and discharge conditions

Geomorphologic evolution of a coastal karst: the Gulf of Orosei (central-east Sardinia, Italy), 2004,
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De Waele, Jo

In the past ten years cave surveying has allowed better understanding of speleogenesis in the Orosei Gulf (Central-East Sardinia, Italy), one of the most important coastal karst areas of Italy. Surface geomorphologic research has been accompanied by subterranean and submarine landform analysis in order to try and understand the evolution of this coastal karst since its emersion in Upper Eocene. The main factors influencing the geomorphic processes are lithology, tectonics, palaeo-climate and sea level changes. The study of several important cave systems demonstrates a complex geological history with karst processes that started in Early Tertiary and accelerated during Plio-Quaternary.

Comparison of 14C and 230Th/234U dating of speleothems from submarine caves in the Adriatic Sea (Croatia), 2004,
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Surić, Maš, A, Jurač, Ić, Mladen, Horvatinč, Ić, Nada

Among the 16 speleothems that were collected from 7 submarine caves and pits for the purpose of 14C and U-Th dating and reconstructing sea-level changes, two speleothems were dated by both methods. Different environmental conditions during the speleothem deposition and after the submergence resulted with different appropriateness for speleothem dating by these techniques. Well preserved speleothems gave reliable results by both methods, while U-Th method showed disadvantage in the case of carbonates contaminated with detrital material, as well as in the case of carbonate from marine overgrowth that covers the speleothems. However, U-Th method using MC ICPMS technique which requires only 100-300 mg of sample per analysis (instead of ca. 30 g for 14C conventional method), offers better age resolution that is essential for speleothem dating.

Isotope records in submarine speleothems from the Adriatic coast, Croatia, 2005,
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Suric Masa, Horvatincic Nada, Suckow Axel, Juracic Mladen, Baresic Jadranka,
Isotope studies, using 14C dating, {delta}13C and {delta}18O measurements, were performed at eight speleothems taken from three submerged caves situated along the eastern Adriatic coast, Croatia. The speleothems were taken from 17 m to 38.5 m depth below mean sea level. The samples consist of four stalagmites and four stalactites in position of growth, covered with marine biogenic overgrowth, and the length of speleothems ranges from ~80 mm to ~190 mm. The youngest (surface) and the oldest (base) layers of speleothems were radiocarbon dated and the 14C ages range from 21,600 cal B.P. to 37,000 yr B.P. During that period the global sea level was more than 40 m below the recent one, so presently submerged objects were under the subaerial conditions necessary for speleothem deposition. 14C ages of the youngest layer range from 21,600 to 32,200 cal B.P. for different submerged speleothems. This indicates the time when the speleothem growth ceased, most probably due to flooding of the cave with either fresh or brackish water. Speleothem growth during the Last Glacial Maximum (30-19 kyr ago) and different time of growth cessation for the different speleothem samples suggest that climate change was not the reason for cessation of deposition. Samples for {delta}13C and {delta}18O measurements were taken from six submerged speleothems with sampling distances of ca. 5-10 mm from the surface to the base of speleothems. Most of the {delta}13C values are in the range from -10.5{per thousand} to -8.5{per thousand}, with few exceptions to -6{per thousand}. These values are typical for Dinaric karst, and very different values for marine biogenic overgrowth indicate that no isotopic exchange took place during the submerged period. {delta}18O values range from -6.7{per thousand} to -4.1{per thousand}. A weak correlation between {delta}13C and {delta}18O values indicates possible kinetic isotope fractionation during the calcite precipitation. If the {delta}18O record is interpreted as climatic signal, it suggests similar climatic conditions for the late Pleistocene and the Holocene, especially no significant differences in temperature and/or moisture transport

The transition of a freshwater karst aquifer to an anoxic marine system, 2005,
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Garman Km, Garey Jr,
Jewfish Sink is located in the shallow seagrass flats of the Gulf of Mexico in west central Florida. Jewfish Sink was a submarine spring until the drought of 1961-1962 when it ceased flowing. Today, the sink is an anaerobic marine basin and provides the opportunity to study the implications of saltwater intrusion in coastal karstic areas. The biogeochemistry of Jewfish Sink was studied from summer 2001 through spring 2004. A distinct feature of the sink is the uniform cold temperature (16-17 degrees C) of the deeper anoxic water that does not match groundwater found nearshore or onshore (22-24 degrees C). There are four zones within the sink: oxic zone, transition zone, upper anoxic zone, and anoxic bottom water. The anoxic bottom water does not mix with water from above but may be linked to deep Gulf shelf water through ancient aquifer conduits. The other three zones vary seasonally in oxygen, salinity, and temperature because of limited mixing in the winter due to cooling and sinking of surface water. The walls of the anoxic zones have characteristic microbial mats that are found in other sulfidic karstic features in the area. Bacterial activity appears to be carbon limited in the anoxic zones where sulfate reduction appears to be the major metabolic process. The reduction of sulfate to sulfide appears to be driven by irregular influxes of organic matter including macroalgae, horseshoe crabs, and stingrays that become entrapped within the sink. Bacterial activity in the oxic zones appears to be phosphate limited. Although the system is partially isolated from the overlying marine ecosystem, organic input from above drives the bacterial anaerobic ecosystem, resulting in a sulfide pump. In this model, sulfide percolates up through the karst and removes oxygen from the overlying sediment, which has likely caused changes in the shallow benthic ecosystem. Jewfish Sink appears to be part of an extensive anoxic subterranean estuary that extends under parts of at least three coastal counties in Florida and can serve as a model for the effects of rising sea levels or aquifer mining

The geochemistry of fluids from an active shallow submarine hydrothermal system: Milos island, Hellenic Volcanic Arc, 2005,
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Valsamijones E. , Baltatzis E. , Bailey E. H. , Boyce A. J. , Alexander J. L. , Magganas A. , Anderson L. , Waldron S. , Ragnarsdottir K. V. ,
Geothermal activity in the Aegean island of Milos (Greece), associated with island-arc volcanism, is abundant both on-and off-shore. Hydrothermal fluids venting from several sites, mainly shallow submarine (up to 10 m), but also just above seawater level in one locality, were sampled over four summer field seasons. Some of the discharging fluids are associated with the formation of hydrothermal edifices. Overall, the main characteristics of the hydrothermal fluids are low pH and variable chlorinity. The lowest recorded pH was 1.7, and chlorinity ranged from 0.1 to 2.5 times that of seawater. The highest fluid temperatures recorded on site were 115 degrees C. Two main types of fluids were identified: low-chlorinity fluids containing low concentrations of alkalis (potassium, lithium, sodium) and calcium, and high concentrations of silica and sulphate; and high-chlorinity fluids containing high concentrations of alkalis and calcium, and lower concentrations of silica and sulphate. The type locality of the high-chlorinity fluids is shallow submarine in Palaeochori, near the cast end of the south coast of the island, whereas the type locality of the low-chlorinity fluids is a cave to the west of Palaeochori. The two fluid types are therefore often referred to as 'submarine' and 'cave' fluids respectively. Both fluid types had low magnesium and high metal concentrations but were otherwise consistently different from each other. The low-chlorinity fluids had the highest cobalt, nickel, aluminium, iron and chromium (up to 1.6 mu M, 3.6 mu M, 1586 mu M, 936 mu M and 3.0 mu M, respectively) and the high-chlorinity fluids had the highest zinc, cadmium, manganese and lead (up to 4.1 mu M, 1.0 mu M, 230 mu M and 32 mu M, respectively). Geochemical modelling suggests that metals in the former are likely to have been transported as sulphate species or free ions and in the latter as chloride species or free ions. Isotopic values for both water types range between delta D -12 to 33 parts per thousand and delta(18)O 1.2 to 4.6 parts per thousand. The range of fluid compositions and isotopic contents indicates a complex history of evolution for the system. Both types of fluids appear to be derived from seawater and thus are likely to represent end members of a single fluid phase that underwent phase separation at depth. Crown Copyright (c) 2005 Published by Elsevier B.V. All rights reserved

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