origin and residence time of groundwater in the tadla basin morocco using multiple isotopic and geochemical tools summary groundwater resources in the tadla basin stem from surface water recharge and different groundwater inflows forming a multilayered aquifer system which hosts one of morocco s most important groundwater reservoirs the hydrodynamic infrastructure i e the relationship between all regional aquifers recharge and the residence time of waters poses a serious challenge for current water management and future exploitation in aiming for a long term sustainable utilization a combined hydrogeologic and isotopic investigation using hydrochemical and isotopic tracers such as 18 o 2 h 3 h 13 c and 14 c was carried out in order to determine the sources of water recharge to the aquifers the groundwater flow system and the residence time of these waters more than one hundred point measurements throughout the study area in varying wells boreholes springs and rivers were investigated chemical compositions of the groundwater indicate an important influence by the host carbonate rocks from each of the tadla aquifers stable isotope results indicate the existence of two groups of groundwater corresponding to the unconfined aquifer in the north and the confined aquifer in the south the 18 o 2 h 3 h and 14 c data indicate that the high atlas mountains in the south and east of the basin which are characterized by high rainfall and low 18 o and 2 h values are currently the major source of recharge for the tadla aquifers a significant recharge zone lies in the northern part of the basin where all the aquifers outcrop the confined zones show depleted 18 o values corresponding to the signature of recharge water from the atlas mountains moreover all isotope data demonstrated clearly that the tassaout springs which are located in the southwest of the basin and were previously interpreted as representing natural outlet of the deep aquifers are comprised of young waters with depleted 18 o and 2 h signatures suggesting a high altitude recharge from the atlas mountain in contrast the unconfined parts of the aquifers show higher values of 18 o indicating an evaporation phenomenon which occurs during infiltration or recharge from irrigation the mixing process of old and recent waters is confirmed by 14 c and 3 h the isotopic data also indicates probable interaction and flow between the different aquifers the isotopic and hydrochemical data is therefore essential in confirming possible mixing relationships between aquifers whereas traditional hydraulic data is not capable to provide a quantitative assessment of these relationships the data generated in this study will certainly encourage the revision and improvement of the current hydrological water resources model for the tadla basin the results provide a framework for development of a comprehensive management plan in which water exploitation shifts towards areas with modern recharge and where young and high quality groundwater is found

early cambrian back arc volcanism in the western taurides turkey implications for rifting along the northern gondwanan margin the lower cambrian tommotian go ebakan formation in western central anatolia is made up of slightly metamorphosed continental to shallow marine clastic rocks with pillowed and massive spilitic lavas and dolerite dykes spilitic lavas commonly amygdaloidal are albite and pyroxene phyric with the metamorphic mineral paragenesis albite calcite sericite epidote tremolite chlorite dolerite dykes mainly include plagioclase and pyroxene as primary minerals and tremolite epidote chlorite as low grade secondary minerals geochemical data show that the spilitic lavas and dolerite dykes are sub alkaline of oceanic tholeiitic basalt character and display a tholeiitic fractional trend characterized by an increase in feo mgo and zr and tio2 in variation diagrams they are characterized by relatively high zr y 2 4 5 relatively high th yb 0 15 1 0 and la nb 0 5 2 5 both show marked negative nb and ti anomalies relative to th and la ce implying a subduction related chemistry chondrite normalized ree patterns display slight enrichment of light ree spilitic lavas la yb n 0 79 1 56 dolerite dykes la yb n 0 89 3 50 fairly comparable with morb the geochemical similarity of the spilitic lavas and dolerite dykes suggests a co genetic origin la nb ratios of both types are slightly higher than average morb values and were possibly formed in the early stages of back arc basin development petrogenetic modelling suggests the mafic rocks of the formation were formed by 9 batch melting of spinel lherzolite in shallower depths c 60 km taken together the data suggest that the early cambrian mafic rocks of the taurus units were developed in a back arc basin along the northern edge of gondwana above the southward subducting oceanic lithosphere and may represent initial rifting that resulted in separation of the peri gondwanan terranes

sources sinks and storage of river sediment in the atlantic drainage of the united states the history of sediment and its movement in the atlantic drainage demonstrate some of the difficulties of modeling sediment on a river basin scale soil erosion was accelerated by a factor of at least 10 when european settlers cleared forests and planted crops although increasing soil conservation practice and decreasing crop farming have since reduced the rates of erosion large quantities of eroded material are still stored on hillslopes and in stream valleys where they continue to augment the sediment loads of the rivers the sediment from this episode of erosion that is largely past can be expected to emerge from storage for many decades and perhaps even several centuries to come the reservoirs that have been built on many of the major rivers trap significant portions of the moving sediment which in some places may be remobilized by large floods essentially all the river sediment that reaches the atlantic coastal zone is trapped in estuaries and coastal marshlands probably less than 5 is deposi

ordovician trilobites from the tafilalt lagerstatte new data and reappraisal of the bou nemrou assemblage

cambrian ordovician depositional sequences in the middle east a perspective from turkey abstract in southern turkey taurus chain or taurides and southeastern turkey border folds of the arabian plate nearly complete cambrian to ordovician successions are preserved four major sedimentary sequences are defined according to the main transgressive events and the subsequent shelf progradations these sequences allow us to link the turkish mostly distal lower palaeozoic detritals to the more proximal arabian formations in spite of contrasting facies the lower palaeozoic development is outlined through four successive steps defined in southern turkey 1 initiation of a cratonic platform regime terreneuvian i e earliest cambrian depositional sequence 1 with fluviatile conglomerates and red bed sediments associated with volcanics 2 development of a stable marine platform late terreneuvian to early ordovician depositional sequences 2 and 3 including widespread but diachronous middle cambrian carbonates and subsequent storm dominated detritals 3 tectonic instability middle ordovician leading to a new palaeogeography on the gondwana platform with the differentiation of a sag basin bedinan qasim depocenter lower part of depositional sequence 4 and 4 glaciation latest ordovician upper part of depositional sequence 4 identified by glaciomarine deposits forming the hirnantian glacial record this thick 2000 m detrital succession records a first order long term subsidence driven cambrian to ordovician transgressive trend and includes second order sequences reflecting interactions between global eustasy and tectonic instability on a larger scale the identification of recurrent sequence stratigraphic features with similar trends in the cambrian ordovician successions on the arabian platform implies that a former location of the taurus domain cannot be situated in the present day eastern mediterranean area but should lie directly north of the arabian platform this location places southern turkey at the junction between the north african segment of the gondwana siliciclastic shelf to the west present day coordinates and the eastern arabian segment in good agreement with mixed faunal signatures from both areas primary control of the tectonostratigraphic development of southern turkey during the lower palaeozoic may be a forced evolution from arc platform to rift drift transitions cordilleran model that has migrated progressively eastwards from the avalonian domain along the northern gondwana margin to the arabian domain throughout the lower palaeozoic

buffers barriers and blankets the dis connectivity of catchment scale sediment cascades abstract catchment configuration and the nature of connectivity within and between landscape compartments affect the operation of sediment cascades and geomorphic responses to disturbance events of differing magnitude and frequency this paper introduces the concept of landform impediments termed buffers barriers and blankets that impede sediment conveyance by limiting the connectivity between landscape compartments buffers restrict sediment delivery to channels barriers inhibit sediment movement along channels and blankets drape channel or floodplain surfaces affecting the accessibility of sediment to entrainment these features operate as a series of switches which turn on off processes of sediment delivery determining the effective catchment area at any given time using previously documented examples the role of these features in affecting the operation of sediment cascades in a low relief passive landscape setting such as the australian landmass is contrasted to examples from high relief uplifting settings in new zealand the australian examples are further explored by examining how changes to landscape connectivity brought about by human disturbance since european settlement have impacted upon landscape sensitivity and prospects for river recovery this approach to analysis of impediments to sediment conveyance is generic and can be applied in any environmental setting

llandovery silurian conodont provincialism an update based on quantitative analysis abstract the llandovery conodont provincialism is reassessed based on a larger dataset than that which was available in 1990 the study interval is divided into two time units the pre telychian and telychian three quantitative methods are adopted in the biogeographic analysis including cluster analysis non metric multidimensional scaling and minimum spanning tree in the pre telychian interval four provinces can be recognized i e the north american baltic siberian timan severnaya zemlya australian and yangtze provinces however only three provinces can be recognized in the subsequent telychian interval the timan severnaya zemlya province existed also in this time interval but austria and australia are combined with the pre telychian north american baltic siberian province and form a new province the baltic austrian siberian australian north american province basan province while tibet and the pre telychian yangtze province form the chinese province the conodont richness shows a latitudinal or temperature dependent gradient the conodont fauna was most diverse in the lower latitudes tropical arid and partly warm temperate climatic zones however the provincialism of the llandovery conodont faunas demonstrates a longitudinal pattern which cannot be the result of any latitudinal factors such as temperature but could be controlled by longitudinal factors probably by the circulation of ocean currents the circulation pattern can also explain the formation of the telychian basan province which probably resulted from the rheic and panthalassa ocean gyres according to the conodont provincialism and the distribution of taxa five types of conodont species can be recognized including limitedly distributed species basan species equatorial species shallow sea realm species and cosmopolitan species the conodont fauna showed a significant change in provincialism from the ordovician to the silurian i e from a latitudinal pattern to a longitudinal pattern the hirnantian glaciation may be one of the controlling factors which resulted in the reorganization of the conodont faunas and the change of their living habits and ecological requirement

water geochemistry controlled by carbonate dissolution a study of the river waters draining karst dominated terrain guizhou province china concentrations of major ions and sr and sr isotopic compositions of two major river systems wujiang river and yuanjiang river in karst dominated regions and during winter were measured the rivers and their tributaries have high total dissolved solid concentrations with tz ranging from 2 1 to 6 3 meq l which are significantly higher than that of the global river average calcium and hco3 followed by mg2 and so42 dominate the chemical composition of major ions in the river waters both na k and cl si account for 5 10 of the cations and anions respectively the waters of the wujiang river have high sr2 concentrations and lower 87sr 86sr ratios 0 7077 0 7110 while those of the qingshuijiang river one of two major tributaries of the yuanjiang river system show higher sr isotopic ratios 0 7090 0 7145 and low sr concentrations the lithology and geography of the river basins largely control the chemical and isotopic compositions of these rivers analyses of the stoichiometry of the river waters show that the water chemistry is controlled by carbonate dissolution by both carbonic and sulfuric acid especially of the wujiang river and suggest an origin of sulfate mainly from atmospheric input because of coal combustion and or oxidation of sulfide minerals in the catchments we identify three main weathering sources limestone dolomite and silicates chemical and sr isotopic composition of wujiang river waters are characterized mainly by limestone weathering while those of the qingshuijiang river waters mainly by dolomite and silicate weathering chemical weathering rates of carbonate and silicate are estimated and the results indicate that the chemical weathering rates of carbonate in the catchments are remarkably high significantly higher than most large rivers it is considered that presence of sulfuric acid in the rock weathering overuse of land and deterioration of vegetation are most likely the key factors responsible for the high weathering rates of carbonate in the catchments

stable isotope 2h 18o and 87sr 86sr and hydrochemistry monitoring for groundwater hydrodynamics analysis in a karst aquifer gran sasso central italy this paper deals with chemical and isotope analyses of 21 springs which were monitored 3 times in the course of 2001 the monitoring program was focused on the groundwater of the gran sasso carbonate karst aquifer central italy typical of the mountainous mediterranean area based on the hydrogeological setting of the study area 6 groups of springs with different groundwater circulation patterns were distinguished the hydrogeochemistry of their main components provided additional information about groundwater flowpaths confirming the proposed classification the spatial distribution of their ion concentrations validated the assumptions underlying the hydrogeological conceptual model showing diverging groundwater flowpaths from the core to the boundaries of the aquifer geochemical modelling and saturation index computation elucidated water carbonate rock interaction contribution by alluvial aquifers at the karst aquifer boundaries as well as impacts of human activities the analysis of 18o 16o and 2h h values and their spatial distribution in the aquifer substantiated the hydrogeology based classification of 6 groups of springs making it possible to trace back groundwater recharge areas based on mean isotope elevations the latter were calculated by using two rain monitoring stations 87sr 86sr analyses showed seasonal changes in many springs in winter spring the changes are due to inflow of new recharge water infiltrating into younger rocks and thus increasing 87sr 86sr values in summer autumn when there is no recharge and spring discharge declines changes are due to base flow groundwater circulating in more ancient rocks with a subsequent drop in 87sr 86sr values the results of this study stress the contribution that spatio temporal isotope monitoring can give to the definition of groundwater flowpaths and hydrodynamics in fissured and karst aquifers taking into account their hydrogeological and hydrogeochemical setting

variability in sediment delivery and storage along river courses in bega catchment nsw australia implications for geomorphic river recovery in many catchments in southeastern australia alluvial stores have been the dominant source of sediments mobilised in the period since european settlement in bega catchment on the south coast of new south wales nsw this has been reflected by dramatic changes to river morphology extensive volumes of material have been released and efficiently flushed to the lowland plain with a sediment delivery ratio of almost 70 however only 16 of these alluvial sediments have been flushed through to the estuary as antecedent controls on valley width have resulted in the lowland plain acting as a large sediment sink the changing nature of sediment source transfer and accumulation zones has varied markedly from subcatchment to subcatchment the volume of material supplied to the lowland plain from differing subcatchments is not related to subcatchment area rather the pattern of river types dictates the spatial variability in storage and transfer over 67 of sediment released has been sourced from just 25 of the catchment from subcatchments characterised by large valley fills cut and fill river style that previously stored extensive volumes of material at the base of the escarpment these parts of bega catchment were especially sensitive to disturbance sediment exhaustion from these parts of the catchment and from river courses elsewhere has major implications for the geomorphic recovery potential of rivers constraining what can be realistically achieved in terms of river rehabilitation

revised stratigraphy and relationships of lower palaeozoic rocks eastern taurus mountains south central turkey lithostratigraphic terminology is revised for rocks of ordovician age in the eastern taurus the seydisehir formation of late middle cambrian to early ordovician age is shown to be applicable in the eastern and western taurus as well as in south eastern turkey near deg irmentas northeast of adana the seydisehir formation is overlain with inferred unconformity by clastic strata of ashgill age referred to the ort tepe formation first defined south of hakk ri in the border folds of southeastern turkey palaeontological evidence is cited for the early silurian llandovery age of the unconformably overlying halityayla formation farther south on the coast near ovacik where the ort tepe formation is as yet unrecorded a general model is proposed showing relationships of cambrian and ordovician rocks and faunas in southern and southeastern turkey

from accumulation to discharge modification of stable isotopes during glacial and post glacial processes the isotopes of the water molecule tritium deuterium and oxygen 18 are considered to be ideal tracers of the water cycle an isobalance of accumulation and discharge from glaciated areas is therefore challenging in this article we review data from the alps concerning both the isotopic information of accumulated snow and ice and the relevant information of glacial discharge on a local to regional scale in the alps the seasonal distribution of accumulated snow is governed by small scale meteorology and exposition and distribution of cold and temperate glaciers from comparison with direct precipitation measurements it follows that uncontrolled erosive loss of parts of the seasonal mainly winter snow cover is more important for input output considerations of glacial discharge reconstruction of mean accumulation rates and palaeotemperatures by means of isotopes than occasional melting or even rainfall events the order of magnitude of the latter is controlled by laboratory and field experiments sublimation and evaporation turn out to be of minor influence if only the absolute values and not the deuterium excess the relationship of both stable isotopes deuterium and oxygen 18 is considered nevertheless during warming periods a pronounced increase of deuterium excess caused by intensive melting and evaporation may be used as an additional climate indicator the different isotopic signature of the seasonal snow cover old glacier ice and groundwater stored in the glacier bed enables a quantitative separation of the individual water components discharging at a given time of the day or the season although several detailed isotope studies are reported a complete isobalance from glaciated areas based on an interdisciplinary approach including hydrology and glaciology is still missing the hydroclimatic imprint of the discharge from glaciated areas remains even on a regional scale snowmelt shifts the more negative isotope values from winter precipitation to the summer months interannual climatic variability and changes in seasonal distribution of precipitation for instance reduced winter precipitation during the late 1980s are recorded by the stable isotopes in precipitation and discharge as well indicating that the modification of the isotopic information during glacial and post glacial processes does not override climatic trends

geochemical and isotopic oxygen hydrogen carbon strontium constraints for the origin salinity and residence time of groundwater from a carbonate aquifer in the western anti atlas mountains morocco summary groundwater in many arid basins particularly in developing countries is the only available water resource that sustains local communities yet information on the basic hydrological parameters and the sustainability of the groundwater exploitation are often lacking this study investigates the origin of groundwater from the lower cambrian carbonate aquifer of the lakhssas plateau in the anti atlas mountains of southwestern morocco the study aims to reveal the origin of the groundwater salinity sources and the residence time of the water the study is based on a comprehensive geochemical and isotopic oxygen hydrogen carbon and strontium investigation of groundwater from different parts of the basin the hydrochemical and isotopes results indicated three types of groundwater in the lakhssas plateau 1 thermal water in the southern part of the basin with solute composition that reflects dissolution of calcium sulfate and calcium carbonate minerals 2 low temperature groundwater at the southern margin of the basin with low salinity chloride content up to 100 mg l and chemical composition that is expected from equilibrium with limestone dolomite rocks and 3 low temperature groundwater in the northern western and eastern margins of the basin with a wide range of salinity chloride up to 800 mg l the different water types had also different stable isotope composition the thermal water was depleted in 18 o and 2 h 18 o as low as 7 6 relative to the southern 5 9 to 5 3 and northern waters 5 7 to 3 8 the differences in 18 o and 2 h between the southern and northern waters are related to elevation that induced fractionation of oxygen and hydrogen isotopes in recharge water originated from coastal moisture the data suggest that the high salinity in groundwater from the northern western and eastern margins of the lakhssas plateau is related to the presence of schist rocks in these areas the distinctive low na cl and br cl ratios coupled with high silica contents and high 87 sr 86 sr ratios up to 0 713 in the saline groundwater provide additional evidences for the link between salinity and the schist rocks in contrast the thermal water had relatively low 87 sr 86 sr ratio 0 7089 which is identical to the secular seawater sr isotope ratio during the early cambrian period and presumably reflects interaction with the early cambrian carbonate and sulfate aquifer rocks in the northern and southern groundwater the 87 sr 86 sr ratios were higher and correlated with the mg ca ratios inferring mixing between the early cambrian limestone and other rocks with higher 87 sr 86 sr such as the schist rocks the radiocarbon data showed 14 c activities ranging from 6 pmc in the thermal water to 62 pmc in the southern water age modeling corrected for dissolution of the carbonate rocks with dead carbon simulated mean residence time of 10 15 ka bp for the thermal water and a range of 0 to 3 ka bp for the northern and southern waters depending on the used models the integration of the data enables us to establish a conceptual model for the origin of groundwater in the lakhssas plateau 1 recharge to the aquifer from relatively heavy isotope depleted recharge water presumably during wetter conditions about 10 15 ka bp the recharge water interacted at high depth with limestone and calcium sulfate minerals and emerged to the surface as thermal water at the southern part of the basin 2 more recent recharge from coastal moisture originated from the atlantic ocean the stable isotope composition of groundwater was controlled by the elevation of their recharge areas recharge at higher elevation particularly in the southern margin resulted in lower 18 o and 2 h values 3 the recharge water interacted with the carbonate aquifer rocks particularly with calcite and dolomite minerals in areas of exposure of schist rocks the water rock interaction induced salinization of the groundwater overall our data reveal that the limited water resources in this semi arid zone of morocco could be in some parts less renewable and also saline future exploitation of this basin will have to account the salinity factor and the suggested contribution of water recharged some thousands years ago

the late ordovician diamictic formations from southwestern europe north gondwana glaciomarine deposits abstract this paper presents a review and a discussion of the clast bearing formations diamicts which occur in the uppermost part of the ordovician succession of numerous regions in southwestern europe lithology facies stratigraphic setting and age are discussed the strong similarities of these formations with contemporaneous glaciomarine deposits of the northern and northwestern margins of the african ice sheet and the late ordovician paleogeographic pattern based upon paleomagnetic data lead to the conclusion that the south european clast bearing formations are glaciomarine deposits supplied with clasts by floating icebergs released from the african ice sheet the proposed paleogeographic model confirms the close connection between southwestern europe and gondwana during early palaeozoic times

the character and age structure of valley fills in upper wolumla creek catchment south coast new south wales australia extensive valley fills at the base of the escarpment in upper wolumla creek on the south coast of new south wales australia have formed from a combination of cut and fill processes the valley fills comprise series of alternating horizontally bedded sand and mud units reflecting reworking of detritus from deeply weathered granites of the bega batholith sand units are deposited as sand sheets or splays on floodplain surfaces or in floodouts that form atop intact valley fill surfaces downstream of discontinuous gullies alternatively sands are deposited from bedload and form bars or part of the valley floor within channel fills organic rich mud units are deposited from suspension in swamps or in seepage zones at the distal margin of floodouts within 5 km of the escarpment valley deposits grade downstream from sand sheet and splay deposition in floodouts to mud deposition in swamp and seepage zones radiocarbon dates indicate that virtually the entire valley fill of upper wolumla creek was excavated prior to 6000 years bp remnant terraces are evident at valley margins the valley subsequently filled between 6000 years bp and 1000 years bp producing valley fills around 12 m deep but no greater than 300 m wide reincision into the valley fill on a scale smaller than the present incision phase is indicated at around 1000 years bp following which the channel refilled portion plans dated from 1865 refer to the study area as wolumla big flat and show large areas of swampy terrain suggesting that the valley fill had re established by this time within a few decades of european settlement the valley fill incised once more upper wolumla creek now has a channel over 10 m deep and 100 m wide in places draining a catchment area of less than 20 km2 1998 john wiley sons ltd

integration of geochemical and isotopic tracers for elucidating water sources and salinization of shallow aquifers in the sub saharan drâa basin morocco abstract in the arid sub saharan of southern morocco groundwater salinization poses a direct threat for agricultural production in six oases basins that are irrigated by water imported from the high atlas mountains here the geospatial distribution of salinity is evaluated in shallow groundwater springs and surface waters in the dr a basin integrating major and trace element geochemistry and isotopic tracers o h sr and b the data show that water discharge from the high atlas mountains to the upper section of the dr a basin is characterized by both low and high salinity a distinctive low 18 o and 2 h composition as low as 9 and 66 respectively typical for meteoric water from high elevation a 87 sr 86 sr range of 0 7078 0 7094 and 11 b of 12 17 the ca mg hco 3 na cl so 4 and ca so 4 compositions as well as the br cl 87 sr 86 sr and 11 b values of the saline water suggest dissolution of lower jurassic carbonates and evaporite rocks in the high atlas mountain catchment storage and evaporation of the imported water in a man made open reservoir causes an enrichment of the stable isotope ratios with a 18 o 2 h slope of 18 o and 2 h as low as 9 and 66 respectively and higher 87 sr 86 sr ratios 0 7107 0 7115 relative to irrigation water and groundwater flow from the upper dr a basin this newly discovered low saline groundwater with a different isotopic imprint flows from the northeastern anti atlas jabel saghro mountains to the northern oases of the lower dr a basin this adjacent subsurface flow results in a wide range of sr isotope ratios in the shallow oases groundwater 0 7084 0 7131 and appears to mitigate salinization in the three northern dr a oases in contrast in the southern oases the higher salinity suggests that this mitigation is not as affective and increasing salinization through cycles of water irrigation and salt dissolution appears inevitable

isotopic and geochemical evolution of ground and surface waters in a karst dominated geological setting a case study from belize central america abstract analysis of stable isotopes and major ions in groundwater and surface waters in belize central america was carried out to identify processes that may affect drinking water quality belize has a subtropical rainforest savannah climate with a varied landscape composed predominantly of carbonate rocks and clastic sediments stable oxygen 18 o and hydrogen d isotope ratios for surface and groundwater have a similar range and show high d excess 10 40 8 the high d excess in water samples suggest secondary continental vapor flux mixing with incoming vapor from the caribbean sea model calculations indicate that moisture derived from continental evaporation contributes 13 to overhead vapor load in surface and groundwater concentrations of dissolved inorganic carbon dic ranged from 5 4 to 112 9 mg c l and 13 c dic ranged from 7 4 to 17 4 so 4 2 ca 2 and mg 2 in the water samples ranged from 2 163 2 6593 and 2 90 mg l respectively the dic and 13 c dic indicate both open and closed system carbonate evolution combined 13 c dic and ca 2 mg 2 and so 4 2 suggest additional groundwater evolution by gypsum dissolution and calcite precipitation the high so 4 2 content of some water samples indicates regional geologic control on water quality similarity in the range of 18 o d and 13 c dic for surface waters and groundwater used for drinking water supply is probably due to high hydraulic conductivities of the karstic aquifers the results of this study indicate rapid recharge of groundwater aquifers groundwater influence on surface water chemistry and the potential of surface water to impact groundwater quality and vise versa

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

late ordovician glaciation in southern turkey abstract we present a new survey of several palaeozoic sections in both the taurus range and the border folds that documents typical glacial features including a glacial pavement and striated dropstones halevikdere formation and demonstrates the former presence of an ice sheet in southern and south eastern turkey evidence for the late ashgill hirnantian age of this episode is provided by macro and microfossils found within the glacial formation the extension of ice related deposits into the northernmost part of the arabian platform mardin region implies a much wider distribution of the ordovician ice sheet than was previously believed and strongly suggests that southern turkey lay close to egypt during the lower palaeozoic

origin and salinity of groundwater from interpretation of analysis data in the mining area of oumjrane southeastern morocco under the arid climate in the southern sub saharan catchments of morocco groundwater is the only permanent water supply usually the groundwater is scarce because of the low recharge however the mining activities in oumjrane area eastern anti atlas mountains reveal that water resources are relatively abundant in the fissured ordovician aquifer to understand this phenomenon geochemical and isotopic investigations were carried out in the region the results show that the quality of water is variable in superficial and deep aquifers the specific conductivities range from 0 44 to 10 ms cm most groundwater samples from the deep aquifer indicate high salinity low ph and co2 anomalies geochemical analyses show that groundwater concentrations are mainly controlled by i evaporite dissolution halite and gypsum ii cation exchange with clay minerals iii silicate hydrolysis and iv dedolomitisation carbonate precipitation takes place in the groundwater issuing from the mine sector the discharge is estimated at 386 t year downstream of the bounhass mine moreover stable isotope 2h and 18o and chemical analyses reveal a clear difference between the alluvial and deep aquifers they also show a local recharge for the alluvial aquifer from saghro inliers low isotope ratios are found in the ordovician formation aquifer indicating a deep water circulation these waters could originate from the high atlas and or saghro mountains and flow through fissures and fault networks connections to regional faults and veins may play a role in it as well as the proximity of the major contact with the high atlas

lower palaeozoic stratigraphy and palaeontology karadere zirze area pontus mountains northern turkey lower palaeozoic rocks in the karadere zirze area east of safranbolu pontides northern turkey range from early ordovician to silurian overlying the probably tremadoc bakacak formation are aydos formation quartzites followed conformably by the karadere formation dated as early arenig to early llanvirn by means of graptolites which are assigned to seventeen genera and include three new forms eoglyptograptus bouceki prolasiograptus haplus praecursor and undulograptus mui late arenig trilobites from the karadere formation include bergamia cyclopyge dionidella leioshumardia and seleneceme in the limestone member of the overlying ketencikdere formation uncommon trilobites suggest only a mid to late ordovician age but con odonts with colour alteration index 5 6 indicate the amorphognathus tvaerensis biozone early caradoc macrofossils are rare in the siltstone member but conodonts from the middle of the unit suggest the highest subzone of the a tvaerensis biozone the youngest visible strata are on acritarch evidence at least as high as caradoc but the ashgill is not confirmed and the contact with overlying silurian rocks is unexposed the findikli formation comprises a lower member black argillites with llandovery graptolites and acritarchs and an upper member grey shales with late wenlock graptolites overlain unconformably by devonian rocks the succession differs significantly from contemporaneous deposits in southern turkey and its affinities lie with western europe including the welsh basin

pervasive palaeogene remagnetization of the central taurides fold and thrust belt southern turkey and implications for rotations in the isparta angle the turkish anatolide tauride block rifted away from the northern margin of gondwana in the triassic which gave way to the opening of the southern neo tethys by the late palaeocene to eocene it collided with the southern eurasian margin leading to the closure of the northern neo tethys ocean to determine the position of the anatolide tauride block with respect to the african and eurasian margin we carried out a palaeomagnetic study in the central taurides belt which constitutes the eastern limb of the isparta angle the sampled sections comprise carboniferous to palaeocene rocks mainly limestones our data suggest that all sampled rocks are remagnetized during the late palaeocene to eocene phase of folding and thrusting event related to the collision of the anatolide tauride block with eurasia to further test the possibility of remagnetization we use a novel end member modelling approach on 174 acquired isothermal remanent magnetization irm curves we argue that the preferred three end member model confirms the proposed remagnetization of the rocks comparing our data to the post eocene declination pattern in the central tauride belt we conclude that our clockwise rotations are in agreement with data from other studies after combining our results with previously published data from the isparta angle that includes our study area we have reasons to cast doubt on the spatial and temporal extent of an earlier reported early to middle miocene remagnetization event we argue that the earlier reported remagnetized directions from triassic rocks in tilt corrected coordinates from the southwestern antalya nappes western taurides are in good agreement with other studies from the area that show a primary origin of their characteristic remanent magnetization this implies that we document a clockwise rotation for the southwestern antalya nappes since the triassic that is remarkably similar to the post eocene 40 rotation of the central taurides for the previously published results that are clearly remagnetized we argue that their remagnetization has occurred in the palaeocene to eocene

impacts of land use change on patterns of sediment flux in weraamaia catchment new zealand forest clearance between the 1890s and the early 1920s subsequent scrub growth and commencement of an afforestation program in 1979 modified the pattern and rate of sediment delivery to valley floors via shallow landslides and gully complexes in a steep headwater catchment 4 8 km2 in new zealand analysis of the historical record air photograph interpretation and field survey indicates that both erosion types occurred across the catchment in the 1938 storm aggrading channel beds and widening the active channel zone in contrast a 1 in 100 year event in 1988 cyclone bola induced numerous shallow landslides but erosion of gully complexes was largely restricted to subcatchments that retained pasture and the geomorphic impact of this event on channels was small the changing volume and calibre of materials delivered to the valley floor and the distribution of gully complexes altered patterns and rates of channel adjustment after the events and the resulting sediment flux development of gully complexes maintained coupling processes with channels for periods up to 102 years forming wide channels in downstream reaches upstream downstream connectivity along the trunk stream was altered by the formation of a large debris fan at the confluence with a tributary subjected to gully complex erosion in contrast slopes subjected to shallow landslides became decoupled from channels within 10 years accelerating channel degradation and narrowing effective conveyance of a large volume of fine grained materials promoted immediate aggradation of gentle gradient channels downstream as gully complex areas stabilized following an increase in forest and scrub cover channel courses became significant sediment sources although shallow landslide activity will continue to induce intermittent aggradation in the future it is inferred that average sediment yield will continue to diminish to levels approaching those experienced prior to clearcutting and the pattern of sediment flux will recover by 2030

late telychian early silurian graptolitic shales and the maximum silurian highstand in the nw anatolian palaeozoic terranes article i nfo the late llandovery included a period of global sea level rise with a maximum in the spiralis graptolite biozone recorded by black graptolitic shales or red beds recent work in the less known silurian successions in the zonguldak terrane nw anatolia has revealed the presence of llandovery graptolitic black shales in the lower part of the findikli formation in the camdag catak and karadere areas in the camdag area the black shale member yielded numerous well preserved graptolite rhabdosomes including oktavites spiralis barrandeograptus pulchellus and retiolites geinitzianus it is suggested that the graptolitic shales in this area were deposited during the spiralis lower lapworthi zones in the catak and ovacik areas black shales intercalated with yellow shales yielded o spiralis and r geinitzianus the deposition of black shales is related to the time of maximum silurian sea level the graptolitic shales in the zonguldak terrane are time equivalents of the late llandovery violet shales with green layers from a less deep basin in e istanbul terrane in the w istanbul terrane reddish sandstones with fe oolitic minerals and brachiopod bearing carbonates were deposited during the late llandovery maximum transgression the early silurian deposits in the zonguldak terrane are more akin to those of e avalonian successions whereas those of the istanbul terrane resemble those of the gondwanan periphery moreover the studied sections enable the recognition of the regressive trend or part of it in this high level stand as indicated by the deposition of pale and grey greenish mudstone layers carbonates and shell beds 2010 elsevier b v all rights reserved

a new late ordovician hirnantia brachiopod fauna from nw turkey its biostratigraphical relationships and palaeogeographical setting late ordovician fossils including the distinctive hirnantia brachiopod fauna have been found in lower palaeozoic successions in istanbul and bolu yigilca western pontides nw turkey the middle ordovician sandbian faunas belong to the cooler water mediterranean province and they are followed by katian brachiopods including sulevorthis nicolella hesperorthis glyptorthis saukrodictya and kullervo and ostracods such as piretella eochilina and klimphores which represent deposition in warmer waters however the mediterranean province usually cooler water brachiopods drabovia and leptestiina also occur the pendik formation includes thin bryozoan rich limestones which probably represent the boda global warming event the overlying turbidites contain a hirnantia fauna developed within a brachiopod diplograptid association above them there are characteristic llandovery rhuddanian aeronian brachiopods such as leangella eoplectodonta stricklandia and hindella with the corals halysites paleofavosites and streptelasma in the bolu area katian brachiopods such as mcewanella dalmanella glyptorthis christiania oligorhynchia nicolella howellites and drabovinella also occur but there the overlying hirnantia fauna is developed within a hirnantia mucronaspis association the fauna and sediments indicate that the western pontides were not very cold during the latest ordovician despite turkey being placed in higher latitudes by previous authors it seems more probable that the pontides were at somewhat lower palaeolatitudes perhaps at about 40 s in those times however the precise palaeogeographical position of the terrane remains uncertain there are no hirnantian glaciogenic rocks there such as are found in the taurides of southern turkey