hydrochemical processes in the lower jordan valley and in the dead sea area abstract changes in the concentrations of major some minor and trace elements occurring in both surface and groundwater of the lower jordan river dead sea drainage basin have been investigated in order to identify the characteristics of the regional aquifers and their recharge areas spider patterns of elements and rare earth distribution patterns pinpoint the characteristic chemical features of groundwater as compared to seawater the high br cl ratios in groundwater are caused either by high br cl ratios in precipitation by leaching of br from bituminous matter or by mixing with brines beyond the epsomite stage the locations of groundwater samples with enhanced b contents coincide with the distribution of gypsum in the beds of the lisan formation which produces water with nearly constant b so 4 2 molar ratios aeolian distribution of the unconsolidated lisan sediments influences the b so 4 ratio in the area of lake tiberias and in the jordan highlands the high gd anomaly in the dead sea water is of geologic origin whereas that in the jordan river and in nahal stream qidron is largely anthropogenic the anthropogenic gd input to the dead sea is insignificant compared to the actual amount in the water of the dead sea hot saline water encountered along the western shores of the dead sea with high gd anomalies indicate that they contain large amounts of ancient dead sea water that mix as hot ascending brines with fresh water the recharge area of groundwater in the lower jordan valley extends largely over limestone and dolomite outcrops of the upper cretaceous judea group weathering of locally underlying lower cretaceous volcanics in the area of pezael beqaot and argaman yield groundwater with 34 s so 4 2 values ranging from 2 to 4 the presence of sulphide bearing bodies in this area is attested to magnetic anomalies detected at depths of several kilometres 34 s so 4 2 indicates very deep groundwater circulation high 34 s so 4 2 15 is typical for marine sulphates from the judea and avedat group limestone the springs located along the northwestern shore of the dead sea discharge water replenished on the eastern judea mountains the increase in the salinity of this water is due to brines flushed from sediments and from adjacent sedimentary rocks which host entrapped brines from the precursors of the dead sea formed during the late stages of lake lisan fresher water flushes out these residual brines as a result of falling sea level salinity increase in groundwater is also affected by the ascent of deep seated hot brines from pre sedom periods along the rift faults calculations of mixing between fresh and highly saline end members show that leaching of anhydrite from sediments precipitation of calcite formation of dolomite albitization of plagioclase and ion exchange with abundant clay minerals control the major element composition of the saline groundwater

chemical composition of rainfall and groundwater in recharge areas of the bet shean harod multiple aquifer system israel the bet shean and harod valleys are regional recipients and mixing zones for groundwaters draining from a regional multiple aquifer system comprising two different carbonate and two basalt aquifers as well as deep seated reservoirs of confined brines this paper the first of two describes the hydrochemistry of the groundwater bodies related to this multiple aquifer system the paper deals with the chemical composition of rain falling on natural recharge areas the chemical contribution of the aquifer rocks and the chemical evolution of groundwaters in the upper flow courses of all aquifers of this regional system the methodology applied is based on the determination of major dissolved ions and on the examination of their ratios and changes along the upper flow paths rain water falling on natural recharge areas has an average chlorinity of 12mgl 1cl and a calcium bicarbonate composition caused by dust borne terrigenous material this rain water salinity decreases with distance from the sea shore fresh groundwaters flowing through the different aquifers may be identified and differentiated by their characteristic salinity levels and ionic ratios groundwaters flowing through carbonate aquifers are identified by different salinity levels and by distinct rmg rca ratios reflecting dolomite calcite ratios in aquiferr rocks the groundwaters of the two basalt aquifers have typical cation assemblages and high na and mg2 concentrations far in excess of those typical of the recharging rainfall groundwater in the upper flow courses of all aquifers investigated is deficient in so2 4 and k relative to recharging rain water

rain shadow hydrology influences on river flows and flood magnitudes across the central massif divide of la grande terre island new caledonia summary within the tropical south pacific islands meaningful examination of how mountain barriers influence river flow characteristics has not previously been attempted owing principally to the lack of reliable long term data from an adequate number of basins that are geographically spread across opposing sides of a major topographic divide the island of la grande terre in new caledonia provides an exception since robust flow records with effective durations between 15 and 52 years are available for 22 monitored rivers draining both sides of a massif dividing range cross island differences in several fundamental hydrological parameters were statistically analysed including runoff coefficients median daily discharges and specific flood flows results identify that significant flow contrasts exist between windward versus leeward basins which are not necessarily revealed by observing patterns of rainfall distribution over the island power relationships are derived using both empirical and theoretically based models for maximum decadal q 10y and centennial q 100y flood size against catchment area with basins grouped according to windward or leeward location on la grande terre a key finding is that the rain shadow influence ri is essentially constant and therefore quantifiable across the central massif divide flood magnitudes for both q 10y and q 100y events are between 35 and 80 greater for windward versus leeward basins of equivalent size depending on whether empirical or accepted theoretical models are applied the term rain shadow hydrology is proposed for the generalised concept of windward vs leeward divergence in hydrological patterns in spite of being developed for the la grande terre situation the theme has relevance for neighbouring high islands in the tropical south pacific and therefore contributes to understanding tropical island hydrological characteristics in the trade wind belt however the transferability of estimated ratios of the rain shadow influence ri ratios requires validation with flow data from other islands especially to establish windward vs leeward differences in flood magnitude basin area relationships

high resolution studies of rainfall on norfolk island part iii a model for rainfall redistribution abstract a dense network of high resolution rain gauges has provided data on spatial scales of about 1 5 km and time scales of 15 sec on norfolk island where the topography is dominated by a 300 m hill that is found to modify the spatial distribution of rainfall depending on wind direction a correlation method is used to track coherent storm motion so as to identify the dominant wind direction and speed transects are selected across the island in the wind direction and the rainfall interpolated along each transect it is found that there is often a decrease in rainfall upwind of the hill followed by an increase downwind of the peak the ratio of downwind to upwind catches increases linearly with wind speed these observations do not accord with the often accepted explanation using a seeder feeder mechanism a simple wind drift model is proposed in which raindrops follow trajectories modified by the perturbed wind flow over the hill the transects are approximated by bell shaped hill profiles analytic solutions for potential flow over a cylinder are then used to find a streamline with a bell shape similar to a topography transect through the hill and aligned with the wind direction this streamline is used as the solid surface boundary thereby giving a direct analytic flow field for the bell shaped hill a streamfunction is found for drop motion allowing rainfall variations to be predicted a parameterisation is developed that explains the shape and magnitude of the observed rainfall variations along a transect agreement between the rudimentary model and observations is found possible to within a few percent this indicates that the wind drift process is viable as the dominating mechanism for determining rainfall distribution in the presence of low hills when low level moisture is absent

geochemical and boron strontium and oxygen isotopic constraints on the origin of the salinity in groundwater from the mediterranean coast of israel in order to identify the origin of the salinity and formation of saline plumes in the central part of the mediterranean coastal aquifer of israel we determined the elemental and boron strontium and oxygen isotopic compositions of fresh and brackish groundwater cl up to 1500 mg l we distinguish between two key anthropogenic sources 1 sewage effluents used for irrigation with high na cl so4 cl and b c1 ratios and low br cl ratios relative to seawater ratios low 11b values 0 10 and high 18o values 4 and 2 imported water from the sea of galilee that is artificially recharged to the aquifer with high br cl 3 10 3 and 18o values 1 and a low 87sr 86sr ratio of 0 70753 the brackish groundwater from the saline plumes have relatively low na cl ratios 0 5 0 8 and high ca mg mg cl and ca so4 hco3 1 ratios relative to seawater ratios marine so4 cl and br cl ratios 11b values of 24 8 49 9 18o of 2 95 to 4 73 and 87sr 86sr ratios of 0 708275 0 708532 the composition of most of the investigated groundwater from the saline plumes differs from those of the anthropogenic sources imported water fresh uncontaminated groundwater 87sr 86sr of 0 70866 11b of 20 30 and saline water from the adjacent eocene aquitard only in areas of artificial recharge does local groundwater have high br cl and 18o values that are typical to the sea of galilee the linear relationships between chloride and most of the ions including b and sr the relatively high 11b 30 and low 18 o 4 values and the chemical signature of the saline plumes e g marine br cl and so4 cl ratios suggest that 1 mixing processes control the chemical composition of the brackish water within the aquifer and 2 the saline postulated end member has a chemical composition that resembles modified seawater with a marine and higher 11b values and a 87sr 86sr ratio of 0 7083 we propose that most of the salinization phenomena and the formation of saline plumes in the inner parts of the coastal aquifer are derived from upconing of underlying natural saline water bodies and enhanced by overexploitation and draw down of the overlying fresh groundwater

multi disciplinary modeling in stratigraphy and groundwater stratigraphy of the jordan river basin the study area is located along the dead sea rift the climate is considered arid in its southern margin near the dead sea which is the lowest water reservoir found on the globe 412 m bsl to semiarid in its northern part during the last few decades the water resources became depleted limiting the natural development of the agricultural settlements which are the most common type of communities in the region previous studies suggested that a large amount of freshwater is lost as the result of salinization processes which occur when fresh groundwater from the mountain aquifers flow into the saline clastic neogene aquifer complex in order to comprehend this complex system a detailed outlining of the regional hydrogeological system is essential since there are no boreholes which penetrate the aquiferous rock sequences within the rift it was necessary to interpolate a large variety of data from several fields of geosciences the methods applied included geological mapping geophysical modeling based on interpretation of seismic profiles and geochemical modeling based on chemical and isotopic analysis of runoff sediments and groundwater the combined modeling based on results from the different types of analyses implied to several conclusions relevant to the regional water management policy 1 groundwater becomes saline as it flows from the margins of the rift to its center therefore it is recommended to exploit it along the foothills of the rift escarpment 2 geophysical modeling indicated that the foothills and the karstic mountain aquifer extend into the subsurface of the valley and can be farther exploited up to 15 mm3 per annum by relatively shallow wells 3 several mechanisms of groundwater salinization were deciphered a the dense vertical faulting systems act as potential conduits for saline water which flow up from deep seated sources and penetrate into the fresh aquifers b fresh groundwater in the clastic aquifer complex is rare furthermore two evaporates bodies were encountered auja and zaharat el qurein also acting as sources for fresh water salinization c although the quantity of runoff recharge to the jordan valley aquifer complex is negligible the increase in its salt content tds turns this negligible freshwater recharge to a significant contributor of salts

the paleoenvironment and the evolution of brines in the jordan dead sea transform and in adjoining areas one of the most important processes leading to the deterioration of groundwater in israel is the migration of brines penetrating into fresh groundwater bodies such manifestations occur at an ever increasing frequency and in unexpected locations the hydrochemistry of these processes reveals the possibility of involvement of several types of brines the distribution and the hydrostratigraphic sequence of the brines is correlated with the evolution of paleoenvironments during the geological history of the region several major phases of brine and evaporite formation are discerned the earliest phase occurred in the paleozoic early mesozoic yam suf ramon lower arad groups during which brines were generated by dissolution of evaporites the second major phase in the evolution of brines occurred during the mio pliocene in the western areas of the country the brines were generated mainly by the post messinian ingression of seawater which dissolved evaporites and reacted with the invaded rock sequence in the rift and in adjoining areas the dominant brine was the final product of the evaporation of an inland marine lagoon the sdom sea which penetrated into an environment prevalently built of previously formed rocks and particularly of clastic beds filling at that time the nascent rift from this evaporating lagoon precipitated evaporates the dissolution of which produced brines a further step in the hydrochemical evolution in the rift was the creation of the lisan lake which became progressively saline probably as the result of dissolution and flushing of salts derived from the previous hypersaline sdom sea the contemporary phase in the rift is characterized by an ongoing process of flushing out of residual brines and dissolution of evaporites by currently recharged fresh water throughout the geological history of the area four major periods of flushing stand out these occurred between the triassic and the jurassic at the end of the jurassic as the result of the oligocene uplift and as part of the messinian event as the result of these processes the rock sequences were flushed off previously formed brines and evaporites and were made ready for following generations of liquids

the rivers of civilization the hydromorphic regimes that underpinned old world river based civilizations are reviewed in light of recent research notable holocene climatic changes varied from region to region whilst the dynamics of floodplain environments were equally diverse with river channel changes significantly affecting human settlement there were longer term trends in holocene hydroclimate and multi centennial length flood rich and flood poor episodes these impacted on five identified flooding and settlement scenarios i alluvial fans and aprons ii laterally mobile rivers iii rivers with well developed levees and flood basins iv river systems characterised by avulsions and floodouts and v large river fed wetlands this gave a range of changes that were either more or less regular or incremental from year to year and thus potentially manageable or catastrophic the latter might be sudden during a flood event or a few seasons acute or over longer periods extending over many decades or even centuries chronic the geomorphic and environmental impacts of these events on riparian societies were very often irreversible contrasts are made between allogenic and autogenic mechanism for imposing environmental stress on riverine communities and a distinction is made between channel avulsion and contraction responses floods droughts and river channel changes can precondition as well as trigger environmental crises and societal collapse the nile system currently offers the best set of independently dated holocene fluvial and archaeological records and the contrasted effects of changing hydromorphological regimes on floodwater farming are examined the persistence of civilizations depended essentially on the societies that maintained them but they were also understandably resilient in some environments pharaonic egypt in the egyptian nile appear to have had more limited windows of opportunity in others the kerma kingdom in the nubian nile or required settlement mobility or exceptional engineering response huang he mesopotamia to accommodate problems such as river avulsion desiccation or local salinization

living with natural hazards in the asia pacific region many might say that it could not be a worse time to live in the asia pacific region in the past few years we have not only experienced the 2004 indian ocean tsunami but also the 2006 java 2007 solomon islands 2009 new zealand 2010 chilean and the 2011 t hoku japan earthquakes and tsunamis we should not forget either the seemingly endless list of other natural hazards such as tropical cyclones and typhoons e g 2010 fiji and philippines volcanic eruptions 2010 indonesia river floods 2010 pakistan wildfires 2009 australia amongst many others for a variety of reasons an increasing number of people in the asia pacific region are either choosing to live or are finding themselves living at the coast sieh 2006 this in itself is not a problem except when they are exposed to hazards such as tsunamis and cyclones it is in this coastal zone though that we have seen the recent effects of devastating natural hazards the value of the work carried out by natural hazards researchers has recently been brought to the forefront of public awareness it is not always easy to recognize the hazards that a low lying coastal area faces either because there may be no previous historic records of large magnitude destructive tsunamis from which we might learn valuable lessons satake atwater 2007 or because people are for various reasons unaware of the area s geological past normile 2011 as we write this editorial the ongoing troubles faced by the fukushima nuclear power plant are broadcast to us daily while it is true that the first reactor was completed there in 1971 an expert panel reviewed the plant s sesimic resistance in 2008 normile 2011 by this time japanese scientists were well aware of the jogan tsunami of 869ad an event that they concluded could recur at about 1000 year intervals this had not been factored into the orginal design plans for the fukushima plant but the opportunity existed to address this issue in 2008 it was not normile 2011 the people of japan and the rest of the world are now living with the aftermath of that decision if there is one thing that is evident from the work that we do on geological hazards it is that it is all too easy to base estimates of magnitude and frequency on extrapolations from historical data these forecasts based generally on a few centuries of data at best are completely inadequate for the big events that have simply not occurred in historic time for some types of climatic and hydrological hazards homogenous and robust datasets are of much shorter duration so any trends are difficult to identify with confidence terry gienko 2010 terry wotling 2011 the implications for such oversights have proven to be catastrophic and it is only through a combination of geological climatic and numerical modelling research combined with more traditional historical studies that we can hope to guard against such events catching us off guard in the future an interesting case in point relates to palaeotsunami work carried out in new zealand over the past 10 years or so that has consistently pointed to there having been a large event affecting the northern coasts of the country in the fifteenth century e g nichol et al 2003 walters et al 2006 goff 2008 goff et al 2010 this signifcant body of literature was largely ignored until recent numerical modelling work found an intriguing similarity in distribution and scale of modelled runup heights with those of the palaeotsunami data power et al 2011 why is this so important palaeotsunami researchers have long proposed that the most likely source for this event was from a large subduction zone event on the tonga kermadec trench to the north of new zealand until recently however numerical modellers and geophysicists did not feel that this was plausible despite warnings from key researchers that simple geophysical hypotheses about maximum earthquake size at subduction zones and about patterns of earthquake recurrence appear to be of limited value in the long term forecasting of the time and size of great subduction zone earthquakes satake atwater 2007 p 368 this point has been re emphasized

boron isotope geochemistry as a tracer for the evolution of brines and associated hot springs from the dead sea israel abstract a boron isotope study combined with analyses of elemental boron lithium and chlorine is used to suggest that brines from the dead sea and on shore hypersaline thermal springs hamme yesha hamme zohar and hamme mazor are the products of interaction of evaporated seawater with detrital sediments the high 11b values of the dead sea brines 55 7 to 57 4 versus nbs 951 and the hot springs 52 2 to 55 7 and low b li ratios 2 0 to 2 3 and 2 5 to 2 7 respectively relative to seawater indicate preferential removal of 10b from the brines and hence boron adsorption onto clay minerals the brackish en feshcha springs and the freshwater en dawid and nahal arugot springs yield lower b contents and 11b values 37 7 to 40 6 and 33 8 to 36 9 respectively the 11b values and b contents of diluted dead sea brines lie on calculated mixing lines between the composition of the brackish and freshwater springs with the composition of the dead sea the 11 b values of the hot springs however given their boron content are significantly lower than those of the mixing lines thus waters from the hot springs cannot be a mixing product of the dead sea brine with freshwater instead the dead sea brine has evolved from the brines of the hot springs through further isotopic fractionation and boron adsorption onto detrital sediments

ca chloride brines at common outlets of the bet shean harod multiple aquifer system israel abstract the bet shean and harod valleys are regional recipients and mixing zones for groundwaters draining into them from a multiple aquifer system which includes carbonate and basalt aquifers and deep seated reservoirs of brine the outlets of the three aquifers are located at the mountain border separating the valleys from the gilboa and ramot issakhar mts the aquifers drain through two types of outlets unique and common the latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers upon reaching the interconnecting zones fresh groundwater flowing from carbonate and basalt aquifers intermix losing their hydrochemical identities ca chloride brines originating from deep seated and confined reservoirs leak along the deep seated faults characterizing the common outlet zones and contaminate the relatively fresh mixing products originating from the three regional aquifers two types of dilute ca chloride brines were identified in the study area the devora type is a hot and hypersaline source brine which was identified at great depth and under very high hydrostatic pressures this brine could be the residual product of seawater that evaporated during the cambrian cretaceous continental interval and subsequent prolonged interaction with surrounding carbonate rocks the neve ur type brine seems to be genetically related to the neogene inland sdom sea that preceeded the contemporary dead sea

geological controls on groundwater chemistry and arsenic mobilization hydrogeochemical study along an e w transect in the meghna basin bangladesh summary hydrogeochemical investigations along an e w transect in the middle meghna basin show groundwater chemistry and redox condition vary considerably with the change in geology groundwater in the holocene shallow 10 g l and salinity on the other hand groundwater from the pliocene dupi tila sandy aquifer in the eastern part is fresh and low in as hco 3 fe and dissolved organic carbon doc but generally low in so 4 2 and no 3 high hco 3 concentrations 250 716 mg l together with high doc concentrations 1 4 21 7 mg l in these aquifers reflect active sources of degradable natural organic matter that drives the biogeochemical process there is generally de coupling of as from other redox sensitive elements in contrast the pliocene aquifers are low in as hco 3 and doc molar ratio of hco 3 h4sio4 suggests that silicate weathering is dominant in the deeper holocene aquifers and in the pliocene aquifers molar ratios of cl hco 3 and na cl suggest mixing of relict seawater with the fresh water as the origin of groundwater salinity speciation calculations show that saturation indices for siderite and rhodochrosite vary significantly between the holocene and pliocene aquifers stable isotopes 2h and 18o in groundwater indicate rapid infiltration without significant effects of evaporation the isotopic data also indicates groundwater recharge from monsoonal precipitation with some impact of altitude effect at the base of the tripura hills in the east the results of the study clearly indicate geological control i e change in lithofacies on groundwater chemistry and distribution of redox sensitive elements such as as along the transect

hydrochemistry to delineate groundwater flow conditions in the mogher al mer area damascus basin southwestern syria the hydrochemistry of groundwater from the mogher al mer area located in southwestern syria has been used as a tool to identify and assess the hydrogeological systems and associated conditions in this arid region of syria groundwater is considered as the main source of water supply for both drinking and irrigation purposes the detailed description of hydrogeochemical conditions including major ions physico chemical and in situ field parameters has underlined the very complex variability of the stratigraphic sequences and hence the numerous hydrogeological units within the study area on the one hand groundwater chemical signature is found to be mainly controlled by the water rock interaction processes in the mountainous western part of the study area on the other hand anthropogenic influences are observed in the eastern plain in terms of recharge mechanisms the region can be considered as a part of a main intermediate or even regional flow system instead of a local one

origin of oils in helez region israel implications for exploration in the eastern mediterranean in this case study of oils in the helez brur kokhav oil field and nearby shows organic geochemical criteria were integrated with geologic data to identify the source rocks and migration paths of the oils the data presented which include terpenoid biomarkers isoprenoid ratios carbon preference indexes and stable carbon isotopes clearly indicate that the oils in helez brur kokhav ashdod and ashqelon wells are genetically related and were derived from the same source rocks rock extracts bitumen from the lower cretaceous gevaram shales differ geochemically from the oils whereas those of the jurassic barnea formation are similar some barnea samples are apparently stained by oil whereas others are indigenous rock extracts therefore we concluded that the barne samples represent both the rock type from which the oils were derived and the migration path the maturity of the oils determined by c29 20s 20r sterane ratio about 0 85 ro equivalent as compared with the maturation configuration in the area implies generation and expulsion from the barnea rock type at a depth of about 4 500 5 500 m the impervious blanket of gevaram shales covering the jurassic barnea limestone and the westward inclination of this unconformable boundary funneled the oils updip eastward the oils were trapped around the zero isopach line of the gevaram shales in jurassic and lower cretaceous rocks under a combination of stratigraphic and structural controls consequently further oil exploration should focus on 1 delineating the gevaram zero isopach line and identifying adjacent traps and 2 identifying barriers on the migration path below the gevaram seal

origin of the groundwater salinity and geochemical processes in detrital and carbonate aquifers case of chougafiya basin central tunisia summary comprehensive investigations of groundwaters were performed in the detrital and carbonate aquifers of the chougafiya basin central tunisia in the present review hydrochemistry and isotopic tools were combined to get an insight into the processes controlling mineralization recharge conditions flow pattern of groundwater and c chemistry in the investigated hydrological system analysis of the dissolved constituents revealed that several processes controlled the observed chemical composition i the dissolution of evaporitic minerals ii cation exchange reactions iii sulfate reduction under anaerobic conditions iv incongruent dissolution of carbonate minerals calcite dolomite coupled with gypsum dissolution and calcite precipitation and v silicates weathering data inferred from 18o and deuterium isotopes in groundwater samples indicated recharge with modern rainfall water characterized by lower 18o and 2h values is interpreted as recharged by non evaporated rainfall originating from mediterranean and atlantic air masses however water with relatively enriched 18o and 2h contents is thought to reflect the occurrence of an evaporation process related to the long term practice of flood irrigation the radiogenic 3h isotope data provided insight into the presence of two recharge periods in the investigated groundwaters waters with 3h contents of 1 tu clearly suggested the occurrence of a contemporaneous recharge probably during the last two decades carbon isotopes provided some insights into the timescales of groundwater flow but mainly revealed that main sources of c are active in the system these are likely dissolved biogenic co2 carbonate dissolution and incongruent reaction of the carbonate matrix mean residence times were determined after correction of the initial activities for dead c from the rock matrix and suggest ages ranging from the present day to the holocene in both upper cretaceous and mio pliocene groundwaters

acidification of shallow groundwater in the unconfined sandy aquifer of the city of douala cameroon western africa implications for groundwater quality and use the alluvial aquifer underlying the city of douala comprises shallow quaternary deposits where groundwater is the main source for domestic and drinking purposes shallow groundwater in the area show signs of acidification with average ph range of 3 8 6 8 long term groundwater chemistry data 1998 2013 hydrogeochemical and r mode factor analysis were used to establish the acidification process of shallow groundwater and also determine possible origin and implications for water quality and use in the area twenty six groundwater sample points three streams and three rain sample points were studied seasonally in the 2006 2008 and the 2010 2013 study periods the data were compared with result of a study 7 years earlier 1998 1999 the results show evidence of acidification manifested by depletion of hco3 a decrease in the ph and increase in so4 and no3 concentrations of shallow groundwater average groundwater ph range is 3 94 7 70 1998 1999 3 8 6 91 2006 2008 and 3 7 6 8 2010 2013 only approximately 16 1998 1999 14 2006 2008 and 11 11 2010 2013 of water samples fall within the range of ph 6 5 8 5 for potable water according to who 1993 the alkalinity acid neutralizing capacity of the shallow groundwater has decreased significantly coupled with increase in the number of zero alkalinities recorded in the 2010 2013 the shallow groundwater is generally undersaturated with common carbonate minerals calcite dolomite therefore providing insufficient acid buffer principal component analysis in combination with hydrogeochemical studies revealed that four main factors are responsible for the groundwater chemistry and acidity 1 acid atmospheric deposition 2 anthropogenic activities industrial effluent discharges and acid spill 3 chemical weathering and 4 coastal atmospheric deposition cation exchange in general the shallow groundwater is not suitable for drinking and domestic purposes with respect to the low ph and elevated nitrate concentration in view of the implications such as increase in corrosion and increased mobilization of toxic elements e g al pb cu zn mn as well as their possible harmful effect on health it is recommended that the causes rate of acidification and the mobility of trace elements be investigated with more details

in search of a characteristic signature for groundwater aquifers a case study from israel the uranium isotopic and hydrogeochemical data of groundwaters in the galilee betshean samaria and beersheva regions of israel obtained from the published literature have been re interpreted according to new ideas gained from a study of uranium concentrations in groundwaters in australia it appears to be a general rule that the uranium concentration of natural waters is proportional to the hco 3 concentration in a way that is characteristic of individual aquifers in the israeli context the major limestone and basaltic aquifers can be clearly distinguished even to the extent of the mixing of waters from these two sources the limitations of tracing groundwater bodies by the 234u238u activity ratios vs u concentration plot are discussed and the need for interpreting uranium isotopic data in conjunction with hydrogeochemical data is demonstrated which suggests that some of the earlier inferences made in the papers discussed especially in regard to the beersheva region could be reconsidered the hco 3 vs u correlation technique appears to be a good technique for tracing and delineating groundwater bodies in an oxidizing environment irrespective of their size residence time and conditions at the time of recharge

saline versus freshwater contribution to the thermal waters of the northern jordan rift valley israel abstract temperature and salinity differences between thermal waters at equal depths on both sides of lake tiberias reveals that the hotter eastern system consists of heated fresh groundwater whereas the western system consists of heated saline groundwater this difference seems to effect exceptional fluorine enrichment in the fresh thermal carbonate aquifer through temperature controlled equilibrium solubility of fluorite and calcite mixing models based on oxygen isotopic composition and other chemical parameters suggest two distant recharge areas for the mezar hammat gader thermal system as well as a rift valley salinity source hydrogeological considerations and chemical constraints i e oxygen and strontium isotopic ratios suggest that heat in the western system is attained through circulation under a normal geothermal gradient while in the eastern system a higher than usual geothermal gradient controls the heat balance

the relationship between the nitrate concentration and hydrology of a small chalk spring israel discharge from a spring draining a small perched cretaceous chalk aquifer in the upper galilee israel was monitored over a period of two years the water has elevated nitrate concentrations with 15n 14n and chemical data suggesting that it is a mixture of low nitrate and high nitrate end members the latter derived from the sewage of a centuries old village served by septic tanks hydrograph data allowed distinction between fissure flow during the period of winter rainfall and matrix drainage during the dry summer months these different flow types however did not have markedly different nitrate concentrations a 50 fold increase in spring discharge due to fissure flow compared with matrix drainage was reflected in only a 35 decrease in nitrate concentrations the relatively high nitrate concentrations in the fissure waters suggests that they have had close contact with and are possibly displaced from the matrix this should help to accelerate the decline in the spring s nitrate concentrations following the recent completion of the village s central sewage drainage system

strontium isotope evidence on the history of oilfield brines mediterranean coastal plain israel abstract the isotopic composition of sr in oil field brines from the mediterranean coastal plain was determined in 18 drillholes 13 of which are oil producing wells the brines are characterized by salinities ranging from 35 to 93 g l tds sr from 28 to 350 mg l sr ca molar ratios from 0 011 to 0 053 and 87 sr 86 sr ratios from 0 7075 to 0 7090 e a 0 7081 0 0004 2 the brines are classified into two groups 1 a mavqi im group brines with relatively high 87 sr 86 sr ratios 0 7087 and 0 7090 sampled from elastics dolomites and anhydrites of upper miocene age 2 b heletz group brines with relatively low 87 sr 86 sr ratios 0 7075 to 0 7081 sampled from sandstones and dolomites of lower cretaceous age equations were derived to show the relations between 87 sr 86 sr ratio of the brines and the processes through which they evolved dolomitization and dissolution reprecipitation it is suggested that both groups of brines originated from mediterranean evaporated seawater during the messinian desiccation the strontium isotope composition of the seawater is reflected in that of both groups of brines the mavqi im group containing the original 87 sr 86 sr ratio 0 7088 the heletz group evolved later on through exchange reactions of those primary brines with a carbonate sequence of cretaceous age and consequently new 87 sr 86 sr ratios 0 7078 could have been developed the effect of the dissolution reprecipitation reactions on the carbonate rocks is estimated to be very slight only around 1 by weight

hydrochemical and isotopic investigation of groundwater of al batin alluvial fan aquifer southern iraq major ions and important trace elements in addition to 18o and 2h were analysed for 43 groundwater samples sampled from the al batin alluvial fan aquifer south iraq the most dominant ions with respect to molarity were na cl so4 2 ca2 mg2 no3 hco3 with total dissolved solids tds averaging 7855 mg l high concentrations were found for the trace elements u mo v b sr and cr this study suggests a hydraulic connection exists near the fan apex between the uppermost part of the al batin aquifer and the underlying dammam aquifer by means of the abu jir fault system except for the effects of extensive irrigation fertilizer use and poorly maintained sewers the groundwater chemistry is mainly controlled by geological processes such as dissolution of evaporites and the enrichment of dissolved ions as a result of the high evaporation and low recharge rate furthermore it is shown that the kuwaiti fuel oil burning during gulf war in 1991 contributed to the enrichment of v and mo in the studied aquifer the spatial distribution of most ions appears to generally increase from the south west towards the north east in the direction of groundwater flow the stable isotopes show heavier values in groundwater with a gradually increasing trend in the direction of groundwater flow due to the decreasing depth to groundwater and thus increasing of evaporation from both groundwater or irrigation return water additionally the stable isotope signature suggests that rainfall from sources in the arabian gulf and the arabian sea is the major source of recharge for the al batin aquifer except for two samples of groundwater all samples were not suitable for potable use according to the who standards most of the groundwater is suitable for some agricultural purpose and for livestock water supply apart from the high salinity boron represents the most critical element in the groundwater with respect to agricultural purposes

hydrochemistry of aquifers in the southern dead sea area southern jordan the demand for water resources in the area south of the dead sea due to continued development especially at the arab potash company apc works necessitates that water quality in the area be monitored and evaluated based on the local geology and hydrogeology the objective of this paper is to provide information on the past and present status of the main aquifers under exploitation or planned for future development two main aquifers are discussed the safi water field presently being operated and the dhiraa water field which is being developed the aquifer developed in the safi water field is shallow and fed by the hasa fault system which drains a significant portion of the karak mountains this aquifer seems to be well replenished within the core where no obvious long term degradation in water quality can be identified however in the low recharge areas within the distal portions of the alluvial fan there has been a degradation in water quality with time the degradation is caused by the dissolution of the lisan marl which is present at the outskirts of the fan system based on hydrochemistry of water in the wells the dhiraa field is a deep 800 950 m aquifer drilled specifically for the extraction of brackish water present in the kurnub aquifer available data indicate that there are at least three distinct water types within this field these water types are variable in quality and there may be potential for mixing of these waters thus affecting the quality of the freshest waters presently available tritium and oxygen isotope analysis indicate that the water is old and possibly nonrenewable

response of a coastal hydrogeological system to a rapid decline in sea level the case of zuqim springs the largest discharge area along the dead sea coast summary the almost instantaneous response of a natural on shore groundwater system to an extremely rapid drop in the level of an adjacent lake is described in this study the study is focused on the zuqim feshcha spring complex located on the northwestern shore of the dead sea which exhibits a drop of tens of meters in its water level over the last few decades in this exceptional field lab fluctuations and trends in the flow regime are recognized as well as the contemporaneous geochemical variations lithological facies variations have a pronounced effect on the underground flow regime the following main processes were recognized a slight shifting of the long standing springs eastward following the retreating shore b extension of the hydrologic system southward without significant change in the total discharge of the entire spring complex the new seepages are characterized by high variability in salinity and c continuous refreshing of the spring water as a result of prolonged flushing of old trapped brines the water of the zuqim springs lie on mixing lines between two local brine types and diluted brine of the lisan lake the precursor of the dead sea based on our findings future development processes in the spring complex are predicted which is essential because of their impact on the endemic ecosystem that relies on this water in addition continuation of the rapid drop in lake level is expected to cause intensification of erosional processes such as deepening of flow gullies shifting of the entire hydrological system southward and migration along with the retreating shore is also expected to continue as well as the continuous decrease in the water salinity

reconstructing the holocene depositional environments in the western part of ancient karnak temples complex egypt a geoarchaeological approach this paper presents the results of a geoarchaeological study undertaken in upper egypt in the western part of the karnak temples complex the geoarchaeological approach helps to better understand the fluvial dynamics of the nile in the proximity of the pharaonic site during the late holocene until recently most researchers assumed that karnak was built on a fluvial island and that a large basin connected to the nile was built in front of the first pylon during the dynastic period however recent excavations conducted by the archaeologists of the supreme council of egyptian antiquities revealed a jetty or quay with probable direct access to the nile therefore in order to reveal in more detail the landscape and waterscape changes in the most western part of ancient karnak a palaeoenvironmental study was conducted we studied several stratigraphic profiles manual boreholes maximum depth of 5 50 m and percussion drillings maximum depth of 25 m sedimentological and magnetic susceptibility analyses helped to characterize nile river deposits and to identify the presence of aeolian deposits associated with wadi fan deposits in the lower part of the drillings fluvial dynamics characterized by flood events sandy accretions and thick nile silts clay deposits are presented and discussed here for later palaeoenvironmental reconstruction accurate leveling of the different profiles and boreholes together with a topographic survey allow us to recover long sedimentological sequences and to correlate the different sedimentary units finally in order to obtain a chronostratigraphic sequence radiocarbon dates were obtained from wood charcoal and ash samples analyses undertaken at the laboratory of radiocarbon dating of ifao cairo egypt the presence of the nile river in front of the first pylon in karnak is attested from the end of the second intermediate period sip ca 1600 bc until the end of roman times ca 350 ad which both correspond to two main phases of nile river floods

the impact of hydrogeological settings on geochemical evolution of groundwater in karstified limestone aquifer basin in northwest sri lanka the geochemical and isotope analysis of groundwaters from the murunkan basin in north western sri lanka was carried out to examine their evolution and recharge sources in order to shed light to enhance the current knowledge of the hydro geochemical processes in a karst geological setting a total of 40 water samples from ground and surface water bodies were collected from the miocene limestone terrain nearby metamorphic and from unconsolidated quaternary terrains for major anions cations and environmental isotopes ratios 18ovsmow and 2hvsmow distinct geochemical differences were noted between waters from limestone terrain and nearby metamorphic terrain indicating the modification of groundwater flow paths bicarbonate chloride rich water is dominated in the limestone terrain in which water flows through a less mineralized aquifer system and is modified by the sea water intrusion groundwater in the metamorphic terrain is modified by dissolving of ca mg rich mineral phases and subsequent ion exchange processes the environmental isotopes of groundwater from both limestone and metamorphic terrains vary from 0 38 to 6 68 and 2 41 to 42 3 for 18ovsmow and 2hvsmow respectively however slightly enriched isotope signatures and low d excess values from limestone terrain indicate an excessive evaporation compared to that of the metamorphic terrain where rapid infiltration occurs through the overlying highly permeable grumusols soil layers

chemical evolution of saline waters in the jordan dead sea transform and in adjoining areas the ca mg relationship in groundwaters strongly points to the overall dolomitization and local albitization the mg ca ratios reveal two trends by which saline waters develop increase of mg ca ratio by evaporation and decreasing mg ca ratios due to dolomitization and albitization br cl vs na cl ratios demonstrate that albitization does not play a major role which leaves dolomitization to be the main source for decreasing mg ca ratios in saline waters in the eastern and southern region of lake kinneret salinization occurs by mixing with a ca mg molar ratio 1 dominates which developed by the albitization of plagioclase in abundant mafic volcanics and the dolomitization of limestones the most saline groundwater of the tabgha fuliya and tiberias clusters could be regional derivatives of at least two mother brines in diluted form one is represented by ha on water the other is a na rich brine of the zemah type additionally a deep seated ca dominant brine may ascend along the fractures on the western side of lake kinneret which is absent on the eastern side groundwaters of the lower jordan valley are chemically different on both sides of the jordan river indicating that the exchange of water is insignificant all saline waters from the dead sea and its surroundings represent a complex mixture of brines and precipitation and local dissolution of halite and gypsum many wells of the arava araba valley pump groundwater from the upper cretaceous limestone aquifer the origin of the water is actually from the lower cretaceous kurnub group sandstones groundwater drawn from the quaternary alluvial fill either originates from kurnub group sandstones eilat 108 yaalon 117 or from altered limestones of the judea group the origin of these waters is from floods flowing through wadis incised into calcareous formations of the judea group on the other hand as a result of step faulting hydraulic contact is locally established between the kurnub and the judea groups aquifers facilitating the inter aquifer flow of the confined kurnub paleowater into the karstic formations of the judea group two periods of neogene brine formation are considered the post messinan inland lagoon resulting in drying up of the sdom sea and the evaporation of the pleistocene samra lake which went further through the stage of lake lisan to the present dead sea for the first period major element hydrochemistry suggests that the saline waters and brines in the jordan dead sea arava valley transform evolved from the gradual evaporation of an accumulating mixture of sea ground and surface water due to the precipitation of carbonates gypsum and halite such an evaporating primary water body was strongly enriched in mg br and b and shows high molar ratios of br cl b cl and mg ca but low na cl ratios the development of the br cl ratio is chemically modelled showing that indeed brine development is explicable that way along with the evaporation brine evaporites formed which are leached by infiltrating fresh water yielding secondary brines with na cl ratios of 1 when primary brines infiltrated the sub surface they were subjected to mg ca exchange in limestones dolomitization and to chloritization and albitization in basic igneous rocks turning them into ca cl brines these tertiary brines are omnipresent in the rift the brines of the late lisan and dead sea were generated by evaporating drainage waters which leached halite gypsum and carbonates from the soil and from the sub surface all these brines are still being flushed out by meteoric water resulting in saline groundwaters this flushing is regionally enhanced by intensive groundwater exploitation in variable proportions the neogene and late lisan lake and recent dead sea brines have to be considered as the most serious sources of salinization of groundwaters in the rift deep seated pre sdom brines cannot strictly be excluded but if active they play a negligible role only

scanning electron microscope evidence for offshore onshore sand transport at fire island new york usa balancing the sediment budget of the atlantic shoreline of long island has proved to be problematic because more sediment has been found to be moving westward in littoral drift than was estimated to be supplied by wave erosion of the ronkonkoma terminal moraine at montauk point there is a need for the existence of an additional possibly offshore source as part of a larger atlantic shore study 11 beach samples from fire island were compared with samples representing the known glacial source at montauk point and also with four offshore samples to the south comparisons were based upon quartz sand grain surface texture patterns derived by scanning electron microscope checklist analysis initial evidence of an offshore onshore link was provided by qualitative results examining surface texture variability between samples illustrated by photographic evidence and written notes this evidence was confirmed consistently during quantitative analysis in particular canonical variate analysis grouped two offshore samples representing deposits of buried glacial to fluvioglacial lobes with beach samples from fire island in adjacent onshore locations or slightly downdrift in addition canonical variate analysis and factor analysis using the spssx package together with cluster analysis using the arthur package depicted the main factors and texture variables largely responsible for sample discrimination the significance of both the offshore onshore link and the associated factors influencing quartz grain surface texture was revealed by the fact that they are strongly related to each other and to the regional geomorphology

rare earths and yttrium hydrostratigraphy along the lake kinneret dead sea arava transform fault israel and adjoining territories rare earth elements and y rey have been analysed in 49 groundwaters from localities in the areas of lake kinneret and the jordan and arava valleys these waters originate from various aquifers and the rey abundances are expected to be controlled by the aquifer rocks the rey pattern allow one to distinguish interaction of waters with basalts basalt limestone interaction zones silicified limestones limestones from the judea and avdat groups upper cretaceous and eocene respectively and sandstones of the lower cretaceous kurnub group groundwater from the quaternary alluvial fill dead sea group are either controlled by judea group limestone or kurnub group sandstone the rey patterns show characteristic features for each group in hydrogeological systems the rocks of natural replenishment areas are usually not the same as rock units from which the waters are collected this becomes evident by comparing the lithostratigraphic groups from which the waters were collected and the hydrochemical grouping according to rey patterns with their characteristic trends and anomalies in many cases there is a correspondence between the lithostratigraphic and the hydrochemical grouping in other cases the 2 groupings disagree this disagreement proves inter aquifer flow of groundwater in some cases the geologically derived aquifers rocks of origin differ from those indicated by rey patterns thus applying the rey grouping new fundamental information for hydrological models can be given and sources of salinisation can be elucidated

late holocene erosion of the canopic promontory nile delta egypt abstract the mouths of the nile delta are sensitive coastal areas their geomorphology primarily being mediated by relative sea level rise and sediment supply to further document the holocene evolution of the nile s canopic mouth a core was taken from the southern shores of abu qir bay close to the ancient canopic channel core bio sedimentology and chronostratigraphy highlight four stages of marine incursion which are juxtaposed upon the general progradation trend of the nile coast in this area compiled age depth points from sediment cores taken in abu qir bay underscore two phases of negative sediment budget at the canopic mouth 1 a first period between 3 5 and 2 ka cal yr bc probably in relation to the well documented mid to late holocene decline in nile flow and 2 a second phase after 0 5 ka cal ad linked to a decline in canopic sediment supply to the coastal area and concomitant with the development of the rashid branch the erosion and reworking of material flattened and lowered the promontory surface by up to 4 m the submersion of the canopic promontory was completed by relative sea level rise primarily controlled by the compaction and liquefaction of unconsolidated lagoonal muds the lowering of the canopic mouth led to the submersion of two ancient estuarine harbor cities known as east canopus and herakleion whose remains lie 4 7 m below present mean sea level it is argued that the subsidence of the two cities cannot explain their abandonment during the late 7th early 8th century ad taking into account the regional occupation pattern during antiquity rather the longevity of the two cities spanning more than 13 centuries shows that adaptation to coastal risks including erosion subsidence and high energy events like storms or tsunamis was the rule

application of multiple isotopic and geochemical tracers for investigation of recharge salinization and residence time of water in the souss massa aquifer southwest of morocco summary groundwater and surface water in souss massa basin in the west southern part of morocco is characterized by a large variation in salinity up to levels of 37 g l 1 the high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation a combined hydrogeologic and isotopic investigation using several chemical and isotopic tracers such as br cl 18 o 2 h 3 h 87 sr 86 sr 11 b and 14 c was carried out in order to determine the sources of water recharge to the aquifer the origin of salinity and the residence time of water stable isotope 3 h and 14 c data indicate that the high atlas mountains in the northern margin of the souss massa basin with high rainfall and low 18 o and 2 h values 6 to 8 and 36 to 50 is currently constitute the major source of recharge to the souss massa shallow aquifer particularly along the eastern part of the basin localized stable isotope enrichments offset meteoric isotopic signature and are associated with high nitrate concentrations which infer water recycling via water agricultural return flows the 3 h and 14 c data suggest that the residence time of water in the western part of the basin is in the order of several thousands of years hence old water is mined particularly in the coastal areas the multiple isotope analyses and chemical tracing of groundwater from the basin reveal that seawater intrusion is just one of multiple salinity sources that affect the quality of groundwater in the souss massa aquifer we differentiate between modern seawater intrusion salinization by remnants of seawater entrapped in the middle souss plains recharge of nitrate rich agricultural return flow and dissolution of evaporate rocks gypsum and halite minerals along the outcrops of the high atlas mountains the data generated in this study provide the framework for a comprehensive management plan in which water exploitation should shift toward the eastern part of the basin where current recharge occurs with young and high quality groundwater in contrast we argued that the heavily exploited aquifer along the coastal areas is more vulnerable given the relatively longer residence time of the water and salinization processes in this part of the aquifer

elucidating the sources and mechanisms of groundwater salinization in the ziz basin of southeastern morocco in the ziz basin located in arid area in southeastern morocco surface waters are scarce and local populations are entirely dependent on groundwater resources for drinking and irrigation in order to evaluate the main factors controlling the origin and salinization of groundwater resources we have investigated the chemical and stable isotope compositions of groundwater and surface water in different areas in the ziz basin upstream and downstream from the hassan addakhil dam which is the major man made reservoir in the basin a large variation in water quality was observed specifically an increase in salinity from north upstream to the reservoir with tds 460 mg l to south downstream tds 16 000 mg l in the northern portion of the basin the low saline groundwater is composed primarily of ca2 and mg2 due to dissolution of carbonate formations in the high atlas mountains in contrast the major dissolved consequents of saline waters are cl so4 2 and na apparently due to dissolution of evaporite minerals gypsum and halite in some areas elevated nitrate contents imply anthropogenic contamination derived from local agriculture the stable isotopes data 18o 8 6 to 8 3 and 2h 55 7 to 53 8 indicate that the high atlas mountains upstream of the reservoir constitute the major source of water to the ziz basin given that this arid basin is entirely dependent on groundwater resources long term salinization of groundwater in the ziz basin could lead to negative effects and reduction of the local agricultural productivity in addition to the degradation of drinking water quality in this region

geochemical modelling ionic ratio and gis based mapping of groundwater salinity and assessment of governing processes in northern gujarat india in semi arid arid regions groundwater is the major source of irrigation drinking and industrial requirements water salinity and shortage are major problems of concern north gujarat india is one such area where highly saline groundwater is generally ascribed to rapid increase of population agriculture and industries induced decline in water table by unplanned abstraction of groundwater however no effort has been made to discriminate the natural and anthropogenic influences on groundwater salinity in this brief background the present study attempts to identify the factors and processes controlling the groundwater salinity in the area based on ionic ratios in integration with various graphical methods saturation indices and geographical information system na ca2 1 indicates the deficiency of ca2 possibly due to caco3 precipitation or ion exchange process na cl 1 and text so 4 2 text cl gg 0 05 suggest salinization is mainly due to wastewater infiltration and or due to irrigation water return flow sea water intrusion in coastal parts vertical and lateral mixing of water and anthropogenic inputs are also responsible for salinization of groundwater ussl diagram na sodium adsorption ratio residual sodium carbonate and magnesium hazard indicate unsuitability of groundwater for irrigation purposes to prevent groundwater salinization appropriate measures need to be taken to control further indiscriminate exploitation of groundwater for irrigation

the impact of freshwater and wastewater irrigation on the chemistry of shallow groundwater a case study from the israeli coastal aquifer differences in the impact of irrigation with freshwater versus wastewater on the underlying shallow groundwater quality were investigated in the coastal aquifer of israel seven research boreholes were drilled to the top most 3 5 m of the saturated zone the water table region wtr in the agricultural fields the unsaturated zone and the wtr below the irrigated fields consist mainly of clayey sands while the main aquifer comprises mainly of calcareous sandstones and sands we show that the salinity and composition of the groundwater at the wtr are highly variable over a distance of less than 1 km and are controlled by the irrigating water and the processes in the overlying unsaturated zone tritium data in this groundwater 4 6 tritium units tu support that these water are modern recharge the water at the wtr is more saline and has a different chemical composition relative to the overlying irrigation water high sar values sodium adsorption ratio in wastewater irrigation lead to absorption of na c onto the clay and release of ca 2c into the recharging water resulting in low na cl 0 4 compared to 1 2 in the wastewater and high ca cl ratios in contrast in the freshwater irrigated field the irrigation water pumped from the aquifer na clz0 9 sarz0 6 is modified into na rich groundwater na clz2 0 due to reverse base exchange reactions the high no3 concentration 100 mg l in the wtr below both fields is derived from the agricultural activities in the freshwater field the source of no3 is fertilizer leachates whereas in the wastewater field where less fertilizers are applied nitrate is probably derived from nitrification of the nh4 in the wastewater some of the original inorganic nitrogen in the wastewater is consumed by the agricultural plants resulting in a lower inorganic n cl ratio in the wtr as compared to that in the wastewater this study demonstrates the important role of the composition of irrigation water combined with lithology and land use in determining the quality of the water that recharge the aquifer below agricultural fields q 2004 elsevier b v all rights reserved

the chemical evolution of kurnub group paleowater in the sinai negev province a mass balance approach abstract the chemical evolution of the kurnub group paleowater was studied starting from rainwater in recharge areas of the sinai and along groundwater flowpaths leading to the natural outlets of this regional aquifer this was achieved by investigating the chemical composition of groundwater ionic ratios degrees of saturation with common mineral species normative analysis of dissolved salts and by modeling of rock water interaction and mixing processes occurring along groundwater flow paths the initial groundwater composition used is from the nakhel well in sinai it evolves from desert rainwater percolating through typical kurnub group lithology in sinai this rainwater dissolves mainly gypsum halite and dolomite together with smaller amounts of marine aerosol and k feldspar at the same time it precipitates calcite sio 2 smectite and degasses co 2 between the area of nakhel and the northern negev the chemistry of kurnub group waters is influenced by dissolution of halite and lesser amounts of gypsum of surficial origin in recharge areas small amounts of feldspars and of dolomite cement in sandstones eroded from the arabo nubian igneous massif of sinai and organic degradation derived co 2 concomitantly there is precipitation of calcite smectite sio 2 and probably analcime characteristic of sediments in continental closed basins north of the negev the kurnub group fluids are diluted and altered by mixing with judea group aquifer groundwaters on the e there is mixing with residual brines from the water body ancestral to the dead sea prior to discharge into the arava valley rock water interaction indicated by netpath and phreeqc modeling is in agreement with lithology and facies changes previously observed in the kurnub group sequence

salt accumulation in the loessial sequence in the be er sheva basin israel evidence of climatic changes is recorded in the salt content of the surface sediments in arid zones in wetter periods airborne salts are removed downward by leaching to the groundwater whereas in drier periods they accumulate the period of salt accumulation in the loessial sediments of the northern negev is about 10 000 yr this period represents the recent aridification phase the beginning of this stretch of time followed the last humid period in the region top paleo soil calcic horizon found in the region and dated 12 000 yr b p is an indicator of this humid period

definition of groundwater flow patterns by environmental tracers in the multiple aquifer system of southern arava valley israel abstract the present paper describes a model for identification and semi quantitative evaluation of the different water bodies replenishing groundwater in the southern arava rift valley the potential sources of recharge into the alluvial aquifer of the valley were assessed by multivariable cluster analysis of environmental tracers such as dissolved ions and stable isotopes this data was also used to determine the flow pattern to the valley and within its alluvial aquifer to the natural outlet of the red sea spatial variations in the chemical compositions of groundwater and of their isotopic ratios are explained as the result of differential rates of replenishment of various water bodies flowing to the arava the alluvial aquifer of the southern arava valley is recharged by the following water bodies 1 lateral subsurface flow caused by infiltration of water from flash floods occurring in the neighbouring mountain massifs 2 upward and lateral groundwater flow from sandstone and carbonate aquifers in the negev and edom mountains and 3 leakage from deep seated brine reservoirs a complete groundwater flow pattern based upon hydrological hydrochemical and isotopic data is presented in a compartmental configuration

the study of the hydrogeological setting of the chamshir dam site with special emphasis on the cause of water salinity in the zohreh river downstream from the chamshir dam southwest of iran dissolution of evaporite formations emergence of salty water springs and intrusion of deep saline waters are important causes in changing the quality of surface water the study area is part of the reservoir and downstream of chamshir dam which is located in watershed of the zohreh river 20 km southeast of gachsaran city southwest iran to construct powerhouse and related structures for supplying water to agricultural lands located in downstream of dam water quality of zohreh river was studied by eight sampling stations in the study area early studies showed that water quality of the zohreh river decreases severely downstream of the chamshir dam spatial variations diagram of major ions piper and composition diagrams of water samples in selected stations mark the presence of two slight and major contaminating zones at sampling station r4 and r5 in these zones concentration of ca so4 and na cl ions increase suddenly results of hydrogeological hydrochemical lithological and tectonics studies showed that even though there are several low discharges springs in the contaminated zone they cannot be related to surface dissolution of evaporate layers by zohreh river there is an important fault zone including chamshir faults i and ii in the contamination zones through which intrusion of sulfate brackish and chloride brine waters occur along the fault zone and then enter zohreh river below its base level in the absence of any surface evidence the fault zone is the main cause of salinity evaluation of water balance salinity in contaminated zones shows that the discharge rate of saline waters to the river is not low and cannot be separated these findings show that there are serious restrictions upon the purposes of the project

reconstruction of mid holocene sedimentary environments in the central part of the thessaloniki plain greece based on microfaunal identification magnetic susceptibility and grain size analyses abstract the study aims to estimate the relative contributions of the two drainage basins of the aliakmon and axios rivers which since the mid holocene have been responsible for building the largest deltaic area in greece sediments from five cores located in the central part of the thessaloniki plain have been studied for their environmental changes using paleontological and sedimentological methods chronostratigraphical evidence was obtained from 14 c ams dating of marine shells peat and organic sediment samples during the holocene marine transgression this large coastal plain was a shallow marine bay reaching approx 35 km inland circa the 4th millennium bc from which the sea subsequently regressed to the east around the middle of the 3rd millennium bc strong fluvial deposition of aliakmon to the east and of axios to the north occurred and was responsible of a gradual change to lagoonal and limnic environmental conditions around the 5th century bc a freshwater lake occupied the westernmost part of the plain microfaunal identification together with magnetic susceptibility measurements and grain size analysis reveal three main environments of sediment deposition that reflect combinations of both concentrated and dispersed sources of magnetic source minerals using remote sensing and a combination of spectral bands landsat tm imagery we identify former fluvial levees and a freshwater lake and give a spatial interpretation of the rivers influences in building this deltaic complex the mechanisms of edification of the plain as well as the roles played by aliakmon and axios sedimentation are described

the nubian sandstone aquifer in the central and northern negev israel delineation of the hydrogeological model under conditions of scarce data abstract the cl content of ground water in the central and northern negev ranges between 250 mg 1 1 in the beer sheva area and 1600 mg 1 1 near the egyptian border where the water is also thermal with high concentrations of sulphates and iron during the last few years groundwater resources in the heavily populated beer sheva area have become endangered by a continuing process of salinization in the course of the present work it was found that in the study area ground water flows through a multiple aquifer system including the jurassic lower cretaceous kurnub group and the upper cretaceous judea group aquifers because of the absence of impermeable beds at the boundary between the two groups brackish ground water flows from the kurnub group into the overlying judea group aquifer moreover numerous faults discovered in the subsurface facilitate lateral inflow of kurnub ground water into the judea aquifer by interpreting new lithostratigraphic data from the kurnub group and seismic surveys made in the study area it is shown that the kurnub aquifer extends far beyond the hitherto known boundaries and contains an additional estimated volume of 51 10 9 m 3 of paleowater the limiting factors of its exploitability are groundwater depth and salinity the rational exploitation of the kurnub paleowater may prevent salinization of the overlying judea group aquifer

rainfall redistribution over low hills due to flow perturbation abstract a simple potential flow model is developed for airflow over low hills the model readily allows incorporation of simple rain microphysics so that drop trajectories can be traced in the region of a hill complex rainfall intensity variations are found in the horizontal and in the vertical and a straightforward modification to the model allows for time dependence to be studied the model is shown to serve as a useful diagnostic tool to describe rain drop redistribution due to perturbed airflow in particular increased rainfall is predicted in the lee of hill peaks and depleted rainfall is predicted on ridges the redistribution effects dominate at low levels in contrast to predictions based on seeder feeder enhancement comparison with field measurements shows good qualitative agreement over low hills and in some cases close quantitative agreement redistribution of rain appears to be a significant process that should be considered in rainfall interpolation and prediction schemes involving hilly terrain

delineation of groundwater salinization in a coastal aquifer bousheher south of iran the geochemical processes controlling chemical composition of groundwater are studied using hydrochemical and isotopic data in abdan dayer coastal plain south of iran the salinity of groundwater in the coastal plain ranges from 1 000 a fresh end member to more than 50 000 s cm 1 a saline end member groundwater salinity increases from the recharge area toward areas with a shallow water table close to the persian gulf coast due to direct evaporation and sea water intrusion as confirmed by mixing binary diagrams stable isotope content and br cl ratio groundwater flow pattern in the study area has been modified due to over pumping of groundwater in recent years which resulted in further saline water migration toward fresh water and their mixing the maximum mixing ratio is estimated about 15 in different parts of the study area according to chloride concentration

geochemical process regulating groundwater quality in a coastal region with complex contamination sources barka sultanate of oman an investigation was carried out to evaluate the geochemical processes regulating groundwater quality in a coastal region barka sultanate of oman the rapid urban developments in barka cause depletion of groundwater quantity and deterioration of quality through excessive consumption and influx of pollutants from natural and anthropogenic activities in this study 111 groundwater samples were collected from 79 wells and analysed for ph ec do temperature major ions silica and nutrients in barka water chemistry shows large variation in major ion concentrations and in electrical conductivity and implies the influence of distinguished contamination sources and hydrogeochemical processes the groundwater chemistry in barka is principally regulated by saline sources reverse ion exchange anthropogenic pollutants and mineral dissolution precipitation reactions due to ubiquitous pollutants and processes groundwater samples were classified into two groups based on electrical conductivity in group1 water chemistry is greatly influenced by mineral dissolution precipitation process and lateral recharge from upstream region jabal al akdar and nakhal mountains in group 2 the water chemistry is affected by saline water intrusion sea spray reverse ion exchange and anthropogenic pollutants besides high nitrate concentrations especially in group 2 samples firm evidence for impact of anthropogenic activities on groundwater quality and nitrate can be originated by the effluents recharge from surface contamination sources ionic ratios such as so4 cl alkalinity cl and total cation cl indicate that effluents recharged from septic tank waste dumping sites and irrigation return flow induce dissolution of carbonate minerals and enhances solute load in groundwater the chemical constituents originating from saline water sources reverse ion exchange and mineral dissolution are successfully differentiated using ionic delta the difference between the actual concentration of each constituent and its theoretical concentration for a freshwater seawater mix calculated from the chloride concentration of the sample and proved that this approach is a promising tool to identify and differentiate the geochemical processes in coastal region hence both regular geochemical methods and ionic delta ensured that groundwater quality in barka is impaired by natural and human activities

the rate of flushing as a major factor in determining the chemistry of water in fossil aquifers in southern israel abstract issar a 1981 the rate of flushing as a major factor in determining the chemistry of water in fossil aquifers in southern israel in w back and r letolle guest editors symposium on geochemistry of groundwater 26th international geological congress j hydrol 54 285ndash 296 a parallel trend has been found to exist between the isosalinity lines and the isopiezo metric lines in the fossil aquifers of the nubian sandstones in southern israel and the central sinai the flow pattern in these aquifers determines the rate of mixing between paleo seawater and paleo meteoric water this flowpattern is determined by the spatial relations between the nubian sandstone outcrops in the central sinai and the major fault lines of the dead sea and suez rift valleys a cumulative chemical composite diagram in which 18o stable isotope data were plotted makes it possible to classify the water and to trace the ratios in the mixture

monuments on a migrating nile river courses migrate but many egyptologists plot the present day river nile on maps of the valley in archaeological times this may have misled interpretations of ancient monuments and settlements we show a river migrating rapidly on historical timescales in the luxor region sweeping 5 km across the valley at rates on the order of 2 3 km per 1000 years satellite elevation data srtm processed by a novel method and landsat imagery are used to trace ancient river levees and extend trends present in 200 years of archive maps thousands of years into the past this supplements observations by ptolemy 121 141 ad and places local geo archaeological studies in a wider spatial and temporal context satellite data are demonstrated to be a relatively quick and easy constraint upon ancient river courses and a basis for investigations along the egyptian nile even in logistically inaccessible regions

saline groundwater in israel its bearing on the water crisis in the country abstract one of the major causes for the deterioration of water quality bearing heavily on the water crisis in israel is the ongoing contamination of its water resources by saline water bodies the present paper reviews the geochemical processes forming saline water lists and explains certain chemical and isotopic parameters which enable understanding these processes and describes the saline groundwater bodies and various salinization phenomena occurring in the country s various aquifers deterioration of groundwater in israel is caused by numerous natural processes such as encroachment of sea water migration of connate highly pressurized brines penetrating into fresh groundwater by subsurface dissolution of soluble salts originating in surrounding country rocks and by water rock interaction in addition to sea water two saline water bodies were identified as the main factors causing salinization of fresh groundwater a ca chloride brines encountered in the jordan dead sea rift valley in various parts of the negev and of the coastal plain and b na chloride saline water identified in the subsurface of the negev and in the southern part of the coastal plain intensive exploitation of groundwater in israel has disturbed the natural equilibrium which prevailed between fresh and saline water the newly established groundwater flow regimes have facilitated the migration of saline water bodies their participation in the active hydrological cycle and the progressive contamination of fresh groundwater these processes which were not anticipated by planners and water resources managers emphasize that large scale groundwater exploitation was undertaken without giving sufficient consideration to the occurrence and subsurface migration of saline water and brines

evaporites marine or non marine division of evaporites into those types that retain information about primary mineralogy textures and structures primary evaporites and those types so extensively altered that few or no primary features remain secondary evaporites only primary evaporites can give unequivocal data bout their marine or non marine origin to help evaluate such primary deposits they have been further divided using the following attributes 1 whether the depositional setting was marine or non marine 2 whether the source water was a seawater b meteoric c hydrothermal d diagenetic e volcanogenic or f mixed specific criteria for making distinctions are 1 kinds of fossils 2 sedimentology of the associated non saline facies 3 kinds of primary saline minerals 4 association of such saline minerals both in qualitative and quantitative terms 5 trace element isotope and fluid inclusion geochemistry of such saline minerals modified journal abstract

nickel dispersion and enrichment at the bottom of the regolith formation of pimelite target like ores in rock block joints koniambo ni deposit new caledonia in new caledonian ni deposits the richest ni silicate ores occur in fractures within the bedrock and saprolite generally several tens of meters to hundred meters below the present day surface fracture related ni silicate ore accounts for high ni grades at least a few weight percent above the average exploited grade 2 5 these ni rich veins are affected by active dissolution precipitation processes at the level of the water table ni in solution is precipitated as silicates in thin layer cementing joints this mineralization is characterized by chemical and mineralogical concentric zoning with an outer green rim around an inner white zone composed from the edge to the centre of the block i a highly oxidized and altered zone ii a green pure ni rich pimelite zone iii a zone limited to a few centimetres with a mixture of ni poor kerolite and ni rich pimelite and intermediate colours and iv a large white mg kerolite mineralization zone this study proposes that the concentric zonation results from evapo precipitation process related to alternate periods of hydration and drying induced by water table movements this extensive dispersion of ni in concentrically zoned ores can partly explain the rather monotonous ni grade of the bulk exploitation at the base of the regolith with values between 2 and 3 wt

aerial observations of hawaii s wake abstract under the influence of the east northeasterly trade winds the island of hawaii generates a wake that extends about 200 km to the west southwest during the harp project in july and august 1990 five wake surveys were carried out by the ncar electra the patterns of wind and aerosol concentration revealed by these flights suggest that hawaii s wake consists of two large quasi steady counterrotating eddies the southern clockwise rotating eddy carries a heavy aerosol load due to input from the k volcano at the eastern end of the wake the eddies are potentially warmer and more humid than the surrounding trade wind air several other features are discussed sharp shear lines near the northern and southern tips of the island dry and warm air bands along the shear lines a small embedded wake behind the kohala peninsula wake centerline clouds hydraulic jumps to the north and south of the island a descending inversion connected with accelerating trade winds and evidence for side to side wake mo

the sedimentary cycle of the boron isotopes abstract marine sediments contain two isotopically distinct components a non desorbable fraction with 11b between 4 3 and 2 8 per mil n 10 and a desorbable component with 11b between 13 9 and 15 8 per mil n 6 the adsorption coefficient k for the uptake of b from seawater by fluvial suspended material mississippi has an experimentally determined value of 1 54 0 05 the associated isotope fractionation factor is 0 974 0 003 empirical values for k determined from the analysis of marine sediments n 6 were between 3 and 4 the amount of b adsorbed onto fluvial suspended material during estuarine mixing is about 9 109 moles yr based on pore water data adsorption experiments and comparative size fraction analyses suspended sediments from the mississippi river vs bottom deposits from the delta there is no evidence for the incorporation of b into detrital sediments at low temperature however the high b content of bauer deep metalliferous sediments must be due to incorporation of seawater b during formation of authigenic silicates the 11b of these minerals is 2 3 per mil hydrothermally altered sediments from dsdp hole 477 guaymas basin gulf of california have variable b contents from 33 ppm similar to the unaltered detritus to 1 2 ppm in the recrystallized material the latter has 11b as low as 9 0 per mil substantially lower than the unaltered material hydrothermal solutions collected from vents adjacent to the hole have boron contents elevated by about a factor of 4 relative to seawater and 11b between 16 5 and 23 2 per mil the b mobilized from the sediments is isotopically fractionated with the fluids being preferentially enriched in the heavy isotope analysis of an oxisol profile developed over granite in the guyana shield showed that boron is partially mobilized during weathering with an isotopic offset of 2 5 per mil between bedrock and soil the observed enrichment of b in shales relative to igneous rocks does not occur during weathering or during exposure to seawater at low temperature incorporation occurs only during burial diagenesis at temperatures greater than about 60 c however the enrichments cannot be attained during a single cycle of primary weathering and burial but must be cumulative over many cycles

groundwater salinization processes and reversibility of seawater intrusion in coastal carbonate aquifers summary seawater intrusion swi has led to salinization of fresh groundwater reserves in coastal areas worldwide and has forced the closure of water supply wells there is a paucity of well documented studies that report on the reversal of swi after the closure of a well field this study presents data from the coastal carbonate aquifer in northeast china where large scale extraction has ceased since 2001 after salinization of the main well field the physical flow and concomitant hydrogeochemical processes were investigated by analyzing water level and geochemical data including major ion chemistry and stable water isotope data seasonal water table and salinity fluctuations as well as changes of 2 h 18 o values of groundwater between the wet and dry season suggest local meteoric recharge with a pronounced seasonal regime historical monitoring testifies of the reversibility of swi in the carbonate aquifer as evidenced by a decrease of the cl concentrations in groundwater following restrictions on groundwater abstraction this is attributed to the rapid flushing in this system where flow occurs preferentially along karst conduits fractures and fault zones the partially positive correlation between 18 o values and tds concentrations of groundwater as well as high no 3 concentrations 39 mg l suggest that irrigation return flow is a significant recharge component therefore the present day elevated salinities are more likely due to agricultural activities rather than swi nevertheless seawater mixing with fresh groundwater cannot be ruled out in particular where formerly intruded seawater may still reside in immobile zones of the carbonate aquifer the massive expansion of fish farming in seawater ponds in the coastal zone poses a new risk of salinization cation exchange carbonate dissolution and fertilizer application are the dominant processes further modifying the groundwater composition which is investigated quantitatively using hydrogeochemical models

pleistocene evolution of the nile valley in northern upper egypt abstract in the el minia district of northern upper egypt the pleistocene deposits of the nile valley include early pleistocene conglomerates of the armant formation and middle pleistocene sands of the qena formation these sediments are exposed along both sides of the valley in terraces at different heights unconformably overlying eocene limestones field observations suggest that the conglomerate facies of the armant formation was deposited in proximal and mid alluvial fans the sands of the qena formation are differentiated into two facies a cross bedded sandstone representative of alluvial fan braided stream environments and a facies of sand interbedded with mud that may have been deposited by a meandering river the heavy minerals of the armant formation are markedly different from those of the qena formation suggesting derivation from different sources surface textures of quartz grains from the qena sands observed by sem exhibit chemical features attributed to a fluviatile origin sand from the armant formation is characterized by mechanical and chemical surface textural features that suggest original aeolian derivation followed by later fluvial sedimentation

epigenetic dolomitization and iron mineralization along faults and their possible relation to the paleohydrology of southern israel abstract iron mineralization occurs in carbonate rocks of the cretaceous judea group in northern sinai and the negev this mineralization along with strong enrichment of trace metals fills fissures and veins the mineralization is not directly emplaced into the judea group limestones but rather within epigenetic dolomites or ankerites which postdate the country rocks the epigenetic phenomena are narrowly restricted to regional tectonic lineaments the association of mineralization phenomena with tectonic zones of high permeability suggests that fluid transfer between two distinctly different geochemical environments was the main mineral emplacing agent epigenetic dolomitization initially resulted from upflow of old mg rich brines along the fault face during later stages the residual cacl 2 brines flowing through the underlying paleozoic mesozoic clastic rocks accumulated fe and trace metals by leaching of volcanic intrusions the introduction via faulting of these pressurized acidic low eh metal bearing brines into the overlying aerated and alkaline carbonate surroundings led to precipitation of fe which in turn scavenged the trace metals the mg rich brines developed during the cambrian lower cretaceous mostly continental time interval the episodic expulsion of pressurized dolomitizing and metal bearing brines was related to various stages of tectonic and igneous activity occuring during the early miocene pleistocene

hydrochemical changes induced by overexploitation of groundwater at common outlets of the bet shean harod multiple aquifer system israel abstract the bet shean and harod valleys are regional recipients and mixing zones for groundwaters draining into them from a multiple aquifer system which includes carbonate and basalt aquifers and deep seated reservoirs of brine the aquifers drain through two types of outlets unique and common the latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers ca chloride brines originating from deep seated and confined reservoirs leak along the major faults and contaminate the relatively fresh groundwaters originating from the regional aquifers during the last two decades the salinity of groundwaters at the outlets of aquifers and in springs discharging into the valleys have increased as the result of overexploitation the changes in the chemical composition of these waters indicated inflow of dilute ca chloride brines which replace at an ever increasing rate the fresh water of the area the inflow of brines is limited to fault zones and seems to be controlled by the counterpressure of the overlying fresh water overexploitation diminishes this counterpressure thus facilitating the progressive upflow of brines

a new look at the chemical and hydrological evolution of the dead sea abstract hydrological models of the dead sea ds indicate that subrecent equilibrium conditions have been maintained by input and evaporation of about 1600 106 m3 yr of surface waters recent diversions of the headwaters have led to a drop of about 0 95 m yr suggesting that waters stored in adjacent aquifers are being drained at a rate of about 200 106 m3 yr chemical modeling of the ds indicates that the chemical evolution of the waters can be explained by a simple mixture and evaporation model this model requires the input of 50 106 m3 yr of hot spring waters similar to those emanating at zohar and evaporation factors of about 50 this model suggests that the ds salts have accumulated over the past 5000 years this indicates that the initiation of the present ds was triggered by the onset of the mid holocene pluvial stage as well as by draining of the freshwater lakes present upstream from the lake review of the data of the springs responsible for the chemical nature of the ds suggests that these waters are of meteoric continental origin and that it is likely that these waters have experienced deep circulation in the rift system before discharging at the surface due to convective forces operating in the rift

evolution of brackish groundater in a typical arid region northern arava rift valley southern israel brackish groundwater in the northern arava valley south of the dead sea is characterized by salinities up to 4000 mg l this groundwater originates from two main aquifers the first is a relatively shallow aquifer composed of clastic and carbonates of the neogene recent hazeva and arava fill formations the second aquifer occurs usually within a depth of 700 1500 m and is composed of lower cretaceous sandstones of the kurnub group no significant differences could be discerned between the concentrations and ionic ratios of these two main groundwater bodies the chemical evolution of the groundwater is the result of two major processes 1 dissolution groundwater flowing through the kurnub group beyond the boundaries of the arava rift valley and through part of the hazeva and arava fill aquifers is characterized by typical ratios na cl 1 and by ca hco3 so4 0 75 the chemical composition of this groundwater indicates a contribution of salts derived from ancient cacl brines such brines are known to have evolved since the neogene in the arava rift valley they are encountered throughout the whole sedimentary succession in the dead sea and northern arava rift valley area intermixing to various degrees with brackish or fresh groundwater the stratigraphic relation between the brackish and saline groundwater bodies is not consistent usually the less concentrated groundwater overlies the more saline there are however cases of transposition possibly indicating the occurrence of unflushed pockets of cacl brines brackish groundwater derived from the two main aquifers is characterized by an excess of mg and so4 such an excess may have evolved from residual salts precipitated as the result of recent or subrecent fractional evaporation of rain and or floodwater under arid conditions water which precipitated crusts of calcite gypsum and halite became enriched in mg and so4 and to a lesser degree in k and na another possible explanation for the excess mg and so4 is the complete evaporation of surface water resulting in the precipitation of kmg sulphates subsequent dissolution by freshflood water would then preferentially dissolve and mobilize these highly soluble minerals

the evaporation path of seawater and the coprecipitation of br and k with halite brines and salt were sampled at the morton bahamas solar salt production facility on great inagua island in the bahamas the brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies at inagua calcium carbonate begins to precipitate at a brine concentration factor of 1 8 times that of seawater gypsum begins to precipitate at a brine concentration of 3 8 times seawater and halite at a concentration factor of 10 6 three of the most concentrated brines from inagua 40 times seawater were evaporated further in the laboratory magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater and potassium bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater the distribution of coefficients of br and k between brines and halite were determined by combining analytical data for the inagua brines with measurements of the br and k content of halites from inagua and of halite which had precipitated from inagua brines during storage the observed average value of dbr is 0 032 in good agreement with some of the previous measurements the measured values of dk are highly variable 0 001 to 0 021 dk for halite precipitated early in the halite facies is in the vicinity of 0 015

regionalization of extreme precipitation distribution using the principal components of the topographical environment this paper deals with the regionalization of the extreme rainfall intensities in the volcanic island of tahiti french polynesia and focuses how the method automatically takes into account the topographical relief features principal component analysis of a digital elevation model supplies a limited set of variables describing the topographical environment these synthetic descriptors are linked to the parameters of the rainfall intensity gumbel distribution by using a stepwise regression adjusted on 20 point rainfall records the model is then applied on a regular 300 points grid node and interpolated using a spline function to provide an approximation of the pluviometric risk all over the island in the case of the island of tahiti the relationship between the rainfall parameter distributions and the topographical descriptors is very strong and the method supplies a direct estimation in space of the rainfall statistics through the regression model validation of the results and comparison with simple kriging interpolation show the relevance of the approach however more data are needed for a better confidence in the parameter estimation in some areas of the island this automatic and objective method could be applied in any mountainous area where topography has a major influence on the precipitation features to characterize the non stationarity of point rainfall statistics in space

national scale evaluation of groundwater chemistry in korea coastal aquifers evidences of seawater intrusion pollution of groundwater by seawater intrusion poses a threat to sustainable agriculture in the coastal areas of korea therefore seawater intrusion monitoring stations were installed in eastern western and southern coastal areas and have been operated since 1998 in this study groundwater chemistry data obtained from the seawater intrusion monitoring stations during the period from 2007 to 2009 were analyzed and evaluated groundwater was classified into fresh 3 000 s cm according to ec levels among groundwater samples n 233 56 7 and 37 were classified as the fresh brackish and saline respectively the major dissolved components of the brackish and saline groundwaters were enriched compared with those of the fresh groundwater the enrichment of na and cl was especially noticeable due to seawater intrusion thus the brackish and saline groundwaters were classified as ca cl and na cl types while the fresh groundwater was classified as na hco3 and ca hco3 types the groundwater included in the na cl types indicated the effects of seawater mixing ca2 mg2 na k so4 2 and br showed good correlations with cl of over r 0 624 of these components the strong correlations of mg2 so4 2 and br with cl r 0 823 indicated a distinct mixing between fresh groundwater and seawater the ca cl and hco3 cl ratios of the groundwaters gradually decreased and approached those of seawater the mg cl na cl k cl so4 cl and br cl ratios of the groundwaters gradually decreased and were similar to or lower than those of seawater indicating that mg2 na k so4 2 and br as well as cl in the saline groundwater can be enriched by seawater mixing while ca2 and hco3 are mainly released by weathering processes the influence of seawater intrusion was evaluated using threshold values of cl and br which were estimated as 80 5 and 0 54 mg l respectively according to these criteria 41 50 of the groundwaters were affected by seawater mixing

ionic and isotopic ratios for identification of salinity sources and missing data in the gaza aquifer abstract groundwater is the only source of fresh water in the gaza strip however it is severely polluted and requires immediate effort to improve its quality and increase its usable quantity intensive exploitation of groundwater in the gaza strip over the past 40 years has disturbed the natural equilibrium between fresh and saline water and has resulted in increased salinity in most areas salinization in the coastal aquifer may be caused by a single process or a combination of different processes including seawater intrusion upconing of brines from the deeper parts of the aquifer flow of saline water from the adjacent eocene aquifer return flow from irrigation water and leakage of wastewater each of these sources is characterized by a distinguishable chemistry and well known isotopic ratios in this paper na cl so4 cl br cl ca hco3 so4 and mg ca ionic ratios were used to distinguish different salinization sources 11b and 87sr 86sr isotopic composition were also included in the model to study their importance in this monitoring task the task of monitoring and the associated decision making process are characterized by a high degree of uncertainty with respect to input data and accuracy of models for this reason probabilistic expert systems and more specifically bayesian belief networks bbns are used to identify salinization origins the bbn model incorporates the theoretical background of salinity sources area specific monitoring data that are characteristically incomplete in their coverage expert judgment and common sense reasoning to produce a geographic distribution for the most probable sources of salinization the model is also designed to show areas where additional data on chemical and isotopic parameters are needed

geomorphological evidence for fluvial change during the roman period in the lower rhone valley southern france abstract the hydrological and geomorphological dynamics of the lower rhone river southern france are studied during the roman period 2nd 1st centuries bc 2nd 3rd centuries ad the crossing of archaeological and radiocarbon dating methods allow to study events at a pluridecadal to centennial scale from the avignon town to the delta the 15 sites where roman fluvial dynamics were recorded show higher flooding frequencies higher energy levels during floods rises in the marshes or groundwater levels and or active morphological dynamics such as channel migrations from 1st century bc to 1st 2nd centuries ad with respect to the encircling periods although this fluvial change does not reach the amplitude of great climatic events such as the little ice age in the rhone valley we show that it is also perceived in other parts of the catchment and could have a climatic origin however this event is not recorded in the immediate mediterranean environment of the lower rhone so that the rhone appears to efficiently transmit a foreign climatic change

the iberian roman humid period 2600 1600 cal yr bp in the zonar lake varve record andalucia southern spain abstract the iberian roman humid period irhp 2600 1600 cal yr bp is the most humid phase of the last 4000 yr in southern spain as recorded in the sedimentary sequence of zonar lake 37 29 00 n 4 41 22 w 300 m a s l a varve chronology supported by several ams 14 c dates allows study of the lake evolution at annual scale in response to human impact and climate changes there are four climate phases within this period i gradual transition 2600 2500 yr ago 650 550 bc from a previous arid period ii the most humid interval during the iberian early roman epoch 2500 2140 yr ago 550 190 bc iii an arid interval during the roman empire epoch 2140 1800 yr ago 190 bc ad 150 and iv a humid period synchronous with the decline of the roman empire 1800 1600 yr ago ad 150 350 varve thickness and geochemical proxies show a multi decadal cyclicity similar to modern north atlantic oscillation nao 60 20 years and solar variability cycles 11 yr the timing and the structure of this humid period is similar to that described in eastern mediterranean and northern european sites and supports the same large scale climate control for northern latitudes and the mediterranean region

hydrochemistry of groundwater at unique outlets of the bet shean harod multiple aquifer system israel abstract the bet shean and harod valleys are regional recipients and mixing zones for groundwater draining to these valleys from a multiple aquifer system which includes carbonate and basalt aquifers and deep seated reservoirs of brine the outlets of these aquifers are located at the mountain border separating the valleys from the gilboa and ramot issakhar mts the aquifers drain through two types of outlets unique and common the latter type is mainly conditioned by the occurrence of fault blocks acting as connecting media between the aquifers ionic ratios of groundwaters flowing through different carbonate aquifers have not sufficient contrast to facilitate precise identification of source aquifers in the case of basalt aquifers the ratios are unequivocal and sufficient contrast enables such an identification

sources of groundwater salinity along the flow path disi dead sea jordan the groundwater along the eastern escarpment of the dead sea shows a variety of chemical compositions with ec values ranging between 500 and a few thousand s cm in this article the different groundwaters were correlated to the aquifers from where they originate and the water rock interactions were elaborated at it was found that the start of intercalations of permo triassic and jurassic rocks in the area and the basaltic dykes and sills are the sources which cause a drastic increase in the salinity of the water these rocks contents of residual evaporites contact metamorphism products sills dykes and secondary altered mineral assemblage of plagioclase pyroxenes and fe mn minerals cause also drastic changes in ionic ratios saturation indices and groundwater types fresh groundwater flows entering the area become gradually after a few kilometres highly salinized and of earthalkali type with prevailing chloride and sulfate instead of being bicarbonate waters

spatial rainfall distribution at a storm event in mountainous regions estimated by orography and wind direction in this paper the orographical effect for rainfall distribution at a storm event is discussed the main effect is represented by the ground forced ascending current of air a three dimensional numerical model of the hydrostatic atmosphere including basin orography is used to estimate the ascending current area for any wind direction the authors also propose a new concept named directional probability of storm event dipose a severe storm is more likely to occur when the wind blows from a high dipose direction rather than from a low dipose direction the wind direction at a storm event is determined from a dipose analysis and is used in the numerical model the calculated ascending air region is regarded as a severe rainfall area in mountainous river basins the results are examined and compared with observations

nile river sediment fluctuations over the past 7000 yr and their key role in sapropel development the provenance pattern of nile river sediments can be used as a proxy for paleoclimatic changes in east africa the 87sr 86sr ratios are particularly appropriate for such provenance investigations because the white nile drains predominantly crystalline basement rocks whereas the blue nile and atbara flow off the ethiopian highlands which consist of tertiary volcanic rocks a high resolution profile of 87sr 86sr and ti al ratios from a well dated core in the nile delta shows a close correspondence with known changes in nile flow over the past 7000 yr at times of higher river flow there was markedly decreased input of blue nile derived and total sediment this change was caused by northward movement of the inter tropical convergence zone resulting in increased vegetative cover in the ethiopian highlands due to higher rainfall and a longer wet season this inverse relationship between nile river flow and sediment flux may have had important implications in the development of agricultural technology in ancient egypt the marked minimum in 87sr 86sr at 4200 4500 yr b p is coincident with the end of the old kingdom in egypt and provides independent evidence that demise of the old kingdom might have been associated with an extended period of catastrophic low floods during the quaternary and late neogene there was periodic deposition of organic rich sediments sapropels in the eastern mediterranean that represent important indicators of major environmental change evidence from the ti al ratio suggests that the pattern of erosion and sediment supply from the nile catchment observed in this study also occurred throughout much of the neogene and quaternary the reduced inputs of blue nile sediment during times of sapropel formation contributed to the increased primary productivity by reducing the amount of phosphate removed on particles and to the observed change to n limitation in the eastern mediterranean which are important characteristics of sapropel deposition

14c dating of deep groundwater in the bengal aquifer system bangladesh implications for aquifer anisotropy recharge sources and sustainability summary environmental isotopes and 14 c dating were applied to estimate ages and recharge sources of deep groundwater 150 m bgl in south east bangladesh with one exception deep groundwater is shown to have been recharged more recently than 10 ka range 3 9 ka mean 7 6 ka under climatic conditions indicated by 18 o and 2 h as similar to the present day groundwater age distributions have been used to infer the scale of aquifer hydraulic anisotropy 2d groundwater flow modelling is able to reproduce the observed vertical profiles of groundwater age as determined at two locations when the aquifer is assigned a permeability anisotropy k x k z of at least 10 3 under these conditions deep groundwater originates as recharge in the hill regions at the eastern boundary of the basin recharge rates estimated from the groundwater ages are close to an estimate of the current rate of deep groundwater abstraction cautious development and careful monitoring are therefore necessary as excessive deep groundwater pumping could draw dissolved arsenic from the shallow levels of the bengal aquifer system bas and contaminate the deep groundwater resource