fossils from quaternary fluvial archives sources of biostratigraphical biogeographical and palaeoclimatic evidence fluvial sedimentary archives have the potential to preserve a wide variety of palaeontological evidence ranging from robust bones and teeth found in coarse gravel aggradations to delicate insect remains and plant macrofossils from fine grained deposits over the last decade advances in quaternary biostratigraphy based on vertebrate and invertebrate fossils primarily mammals and molluscs have been made in many parts of the world resulting in improved relative chronologies for fluviatile sequences complementary fossil groups such as insects ostracods and plant macrofossils are also increasingly used in multi proxy palaeoclimatic and palaeoenvironmental reconstructions allowing direct comparison of the climates and environments that prevailed at different times across widely separated regions this paper reviews these topics on a regional basis with an emphasis on the latest published information and represents an update to the 2007 review compiled by the flag inspired igcp 449 biostratigraphy subgroup disparities in the level of detail available for different regions can largely be attributed to varying potential for preservation of fossil material which is especially poor in areas of non calcareous bedrock but to some extent also reflect research priorities in different parts of the world recognition of the value of biostratigraphical and palaeoclimatic frameworks which have been refined over many decades in the core regions for such research particularly for the late middle and late pleistocene of nw europe has focussed attention on the need to accumulate similar palaeontological datasets in areas lacking such long research histories although the emerging datasets from these understudied regions currently allow only tentative conclusions to be drawn they represent an important stage in the development of independent biostratigraphical and palaeoenvironmental schemes which can then be compared and contrasted

the role of hydrogeological base level in the formation of sub horizontal caves horizons example from the dead sea basin israel this paper deals with the hydrogeological relationship between base levels of saline lakes and the formation of sub horizontal caves the mechanism presented here suggests that many horizontal cave levels in carbonate sequences are created adjacent to the saline lakes shorelines because of the converging of the groundwater flow above the fresh saline water interface the main factors that control enhanced carbonate dissolution and cave formation are high groundwater flow velocities in the shallow phreatic zone during a relative long steady state of the water table high groundwater flow velocities are evident close to the dead sea due to the convergent fast flows above the shallow interface adjacent to the shoreline the same could prevail in the case of previous paleo lakes that existed in the basin the synergetic combination of the above preconditions for enhanced cave formation seems to be responsible for the formation of elevation controlled alignment of paleo near shore cave levels in the central and southern dead sea portion of the study area these are found on the western fault escarpment and basin margin in different stratigraphic horizons of carbonate lithology many of the cave levels can be linked to late quaternary holocene lake levels obtained from dated lake sediments within the basin the most common cave s elevation was found to be around 200 m below sea level which was the elevation of the lisan lake during part of its history on the other hand the hula basin in the northern part of the dead sea basin was not occupied by saline water bodies since its formation as a base level and thus the above preconditions for enhanced cave formation did not prevail indeed this is evident by the lack of horizontal cave levels on its western carbonate margins unlike the situation in the south

on the use of the radon transform to estimate longshore currents from video imagery abstract larnier s almar r cienfuegos r lejay a 2014 on the use of the radon transform to estimate longshore currents from video imagery in green a n and cooper j a g eds proceedings 13th international coastal symposium durban south africa journal of coastal research special issue no 70 pp 023 028 issn 0749 0208 in nearshore applications the estimation of longshore currents is of primary importance since it controls the alongshore sediment transport and coastal evolution direct estimation of longshore currents using in situ instruments is difficult and costly especially under highly energetic wave climates low cost remote sensing systems based on video observations constitute a promising alternative when the drifting sea foam left after the passage of breaking waves is visible in this paper we describe a method based on longshore timestacks that necessitates less data than approaches using the full video frames our approach uses the radon transform applied on the tim

new discoveries at the middle pleistocene acheulian site of gesher benot ya aqov israel abstract the gesher benot ya aqov archaeological site in the northern dead sea rift of israel contains acheulian artifacts and middle pleistocene fossils initial results of a new interdisciplinary study have shown that fluviolacustrine sediments of the benot ya aqov formation which contains several archaeological occupations were deposited in an embayment of the hula basin they were subsequently deformed by tectonic activity associated with the dead sea rift biostratigraphy magnetostratigraphy and k ar dating serve to constrain the age of the benot ya aqov formation to between 240 000 and 730 000 yr b p archaeological excavation of three areas and two trenches at the new study area have produced abundant basalt flint and limestone artifacts mammalian and avian fossils and considerable plant material the lithic materials provide an excellent opportunity to study large assemblages of in situ acheulian artifacts a rare phenomenon in the middle pleistocene levantine record in addition the organic materials will facilitate paleoenvironmental reconstructions from an ecological floral perspective

mass flux and undertow in a surf zone abstract the mass of water carried shoreward by the breaking waves in a surf zone will in a two dimensional situation be compensated by a seaward return flow the undertow it is shown that the undertow is driven by the local difference between radiation stress and the set up pressure gradient which only balance each other in average over the depth turbulent shear stresses are required to maintain a steady situation comparison with measurements confirms the theoretical results

intertidal beach profile estimation using video images abstract in this paper we present a technique suitable for measurement of intertidal bathymetry over a broad range of length scales 10 1 to 10 3 m and time scales days to decades a series of time averaged images of the swash zone are used to map contour lines of the beach surface in each image contours are identified using bands of maximum brightness associated with breaking waves at the shoreline by mapping the location of these bands in a sequence of images collected over one tidal cycle contour maps of the intertidal bathymetry are generated we expect this technique to work best smallest absolute error under waves which are nearly reflective at the shoreline but break enough to be observed visually this is typical of a barred beach since the wave height at the shoreline is limited by wave breaking over the bar crest the ability of the measurements made with this technique to resolve actual beach elevation variation depends on the ratio of the measurement error variance to the true beach elevation variance thus large measurement errors may be compensated by either large tidal ranges or large temporal changes of the beach itself in a comparison to bathymetry surveyed using a differential global positioning system dgps during the duck94 experiment in duck n c the image based elevation estimates were well correlated with the actual bathymetry the deviations imagebased vs dgps measurements may be partially attributed to effects scaled by wave height at the shoreline wave induced setup and wave height saturation over the sand bar in particular setup was important during dissipative conditions the rms deviation vertical between the dgps and image based bathymetry was reduced from 0 24 m to 0 06 m by correcting for the systematic deviations due to variations in setup and wave height saturation further improvement of the elevation estimates resulted from parameterizing the actual bathymetry with a simple plane beach surface which reduced random or unresolvable measurement errors this led to estimates of the beach slope that were accurate to within 10 of the actual slope and estimates of the cross shore location of the mean sea level line accurate to about 0 50 m

the relationship between current and paleo groundwater base levels abstract base levels are basically divided into two categories oceanic and marine base levels and continental terminal endorheic ones the marine domain serves as the ultimate base level for both surface and groundwater drainage systems continental inland depressions very often serve as terminal endorheic base levels to both surface drainage and groundwater systems many of the current both marine and inland base levels served also in the past as paleo base levels fluctuations of base level elevations affect the adjoined groundwater system in several ways such as changes in groundwater levels location of divides depths of fresh saline water interfaces and the amount of flow to the base levels this paper provides examples from many different parts of the world that describe the relationship between current and paleo base levels the examples include marine base levels as well as inland endorheic ones both currently above and below sea level close to and distant from the sea

environmental and climatic control on seasonal stable isotope variation of freshwater molluscan bivalves in the turkana basin kenya abstract we present growth incremental stable isotope records 18o and 13c of modern and 2 ma fossil bivalve shells from the semi arid turkana basin n kenya s ethiopia these data suggest that seasonal cyclicity in 18o and 13c recorded by modern and fossil shells is driven by wet dry seasonal changes in host water chemistry forced by monsoonal rainfall over the ethiopian highlands fully lacustrine shells show lower amplitude or even absent seasonal cyclicity in comparison with deltaic or riverine shells because of the buffering effect of the large water volume in the lake setting riverine shells arguably have the clearest relation to seasonally variable climate parameters riverine molluscs thus provide a potentially valuable proxy for varying rainfall 18o values in the turkana basin catchment cross plots of molluscan 18o and 13c data reveal dominant environmental control on molluscan isotope values with remarkably large isotopic differences between lacustrine deltaic and riverine environments we interpret this isotope pattern to directly result from the different mixing proportions of omo river source water with evaporated lake water in these environments the interpretation of fossil molluscan 18o and 13c data in a palaeoclimatological context is not straightforward since the potential influence of temporal changes in lake water temperature surface evaporation or river discharge on the 18o budget of the lake is smaller than the isotopic shifts caused by shifting facies patterns in the sedimentary record even though it is clear from the rich molluscan faunas that the 2 ma palaeo lake lorenyang must have been significantly less alkaline than modern lake turkana and likely provided good drinking water and abundant availability of food for the different species of hominins inhabiting the region at that time stable isotope values of molluscan bivalves are not suitable to record the difference in alkalinity between these two settings

an optical technique for the measurement of longshore currents 1 we present an optical method optical current meter to measure the longshore component of nearshore surface currents by measuring the alongshore drift of persistent sea foam in the surf zone the method uses short time series of video data collected from an alongshore array of pixels these space time data are first fourier transformed to a frequency wave number spectrum and finally to a velocity spectrum a model of the velocity spectrum is fit to the observed spectrum to estimate the foam drift velocity confidence intervals and other measures of the input and output data quality are calculated field test comparisons were made against an in situ bidirectional electromagnetic current meter on the basis of 1 month of video data from the 1997 sandy duck field experiment the root mean square error between the two approaches was 0 10 m s linear regression analysis showed the gain between the two instruments to not be statistically different from one differences between the surface and interior measurements were compared to forcing mechanisms that may cause surface velocity shear velocity offsets and alongshore wind stress were well correlated for cases when waves and wind were not aligned to within 45 when wind and wave forced currents are reasonably separable calculated wind dependent surface current shear modeled as a surface boundary layer correlated well with the observed velocity offsets for observations of nonalignment between wind and waves this technique can be applied to study large scale coastal behavior

the river orontes in syria and turkey downstream variation of fluvial archives in different crustal blocks the geomorphology and quaternary history of the river orontes in western syria and south central turkey have been studied using a combination of methods field survey differential gps satellite imagery analysis of sediments to determine provenance flow direction and fluvial environment incorporation of evidence from fossils for both palaeoenvironments and biostratigraphy uranium series dating of calcrete cement reconciliation of palaeolithic archaeological contents and uplift modelling based on terrace height distribution the results underline the contrasting nature of different reaches of the orontes in part reflecting different crustal blocks with different histories of landscape evolution upstream from homs the orontes has a system of calcreted terraces that form a staircase extending to 200 m above the river new u series dating provides an age constraint within the lower part of the sequence that suggests underestimation of terrace ages in previous reviews this upper valley is separated from another terraced reach in the middle orontes by a gorge cut through the late miocene early pliocene homs basalt the middle orontes terraces have long been recognized as a source of mammalian fossils and palaeolithic artefacts particularly from latamneh near the downstream end of the reach this terraced section of the valley ends at a fault scarp marking the edge of the subsiding ghab basin a segment of the dead sea fault zone which has been filled to a depth of 1 km by dominantly lacustrine sediments of pliocene quaternary age review of the fauna from latamneh suggests that its age is 1 2 0 9 ma significantly older than previously supposed and commensurate with less uplift in this reach than both the upper and lower orontes two localities near the downstream end of the ghab have provided molluscan and ostracod assemblages that record somewhat saline environments perhaps caused by desiccation within the former lacustrine basin although they include fluvial elements the ghab is separated from another subsiding and formerly lacustrine depocentre the amik basin of hatay province turkey by a second gorge implicit of uplift this time cut through palaeogene limestone the ne sw oriented lowermost reach of the orontes is again terraced with a third and most dramatic gorge through the northern edge of the ziyaret dagi mountains which are known to have experienced rapid uplift probably again enhanced by movement on an active fault indeed a conclusion of the research in which these various reaches are compared is that the crust in the hatay region is significantly more dynamic than that further upstream where uplift has been less rapid and less continuous

longshore surface currents measured by doppler radar and video piv techniques mean longshore surface currents within the surf zone were measured using two remote sensing techniques microwave doppler radar and optical video doppler radar relies on small scale surface roughness that scatters the incident electromagnetic radiation so that velocities are obtained from the doppler shift of the backscattered radiation video relies on texture and contrast of scattered sunlight from the sea surface and velocity estimates are determined using particle imaging velocimetry piv this paper compares video piv and doppler radar surface velocities over a 1 km alongshore by 0 5 km cross shore area in the surf zone of a natural beach the two surface velocity estimates are strongly correlated r2 ges 0 79 over much of the surf zone estimates differ at the outer edge of the surf where strong breaking is prevalent with radar estimated velocities as much as 50 below the video estimates the radar and piv velocities at particular locations in the surf zone track each other well over a 6 h period showing strong modulations in the mean alongshore flow occurring on 10 20 min time intervals in one case both systems observe a strong eddy like mean flow pattern over a 200 m section of coastline with the mean alongshore current changing direction at about the mid surf zone the good spatial and temporal agreement between the two remote measurement techniques which rely on very different mechanisms suggests that both are reasonably approximating the true mean longshore surface velocity

turbulent mixing in the amazon river the isotopic memory of confluences earth and planetary science letters 290 2010 pp 37 43

the snowmelt of mt hermon and its contribution to the sources of the jordan river abstract the water resources of the upper jordan river basin particularly the main springs are partially fed by the snowmelt of mt hermon mount hermon is an uplifted anticline extending along the northern border of israel and covering an area of 1200 km 2 of which 750 km 2 is included in the jordan river watershed most of mt hermon is composed of karstic limestone of jurassic age 2000 m thick the annual amount of precipitation over the jordan river sources watershed is estimated to be 8 5 10 8 m 3 the water yield of the jordan tributaries is 5 10 8 m 3 with 4 10 8 m 3 of it being discharge from karstic springs to date there are almost no data or estimates of the magnitude of snowmelt recharge and its areal and temporal distribution inaccessibility to most parts of the mountain is the main reason for the lack of data during the last four years research has been conducted to find characteristic parameters that represent the relationship between the mt hermon snowcover and its contribution to dry weather discharge of the jordan river tributaries snow depth and water content were measured at several locations in the altitude range 1500 2100 m above sea level a s l the snow covered area was obtained from landsat images and from aerial photographs the snow lines were delineated on 1 250 000 scale maps and their area was measured these data were compared with the dry weather water yield of the jordan tributaries and the main springs significant contribution from the snowpack was found only above 1400 m the areal extent of the pertinent snowcover is 185 km 2 representing about 25 of the total drainage basin of the jordan head waters the mean water content at the snow gaging sites increased from 10 cm at an elevation of 1500 m 65 cm at an altitude of 2100 m a s l based on these values a preliminary estimate yielded a volume of 5 10 7 m 3 which is about 30 of the dry weather discharge this may be considered as the potential snowmelt recharge to the jordan river main springs

holocene sea level changes along the mediterranean coast of israel based on archaeological observations and numerical model local sea level curves reflect global eustatic changes regional isostatic adjustments of the crust to changing ice and ocean volumes and tectonically controlled crustal movements in this study we evaluate the relative contribution of each of these factors to the holocene sea level curve of the mediterranean coast of israel we use archaeological data as constraints on palaeo sea levels and we then compare the observational limits with isostatic models for sea level change across the region the isostatic model includes the contribution arising from the relative minor increase in ocean volumes for the past 6000 years due to residual melting of ice sheets the effect of the changing shape of the ocean basin the time dependence of shorelines as sealevel changes and the changing surface area occupied by ice sheets differences if significant between the observed and predicted change are interpreted as being of tectonic origin the archaeological observations and the model sea level curve along the mediterranean coast of israel were found to be generally consistent and any discrepancies lie within the uncertainties of both values our model predicted that 8000 years ago sea level at the israel coast was at about 213 5 2 m whereas the archaeological data place it at 216 5 1 m by 7000 bp the predicted level has risen to about 27 1 m consistent with the archaeological evidences according to both observations and predictions sea level was still lower than 2 3t o24 5 m at 6000 bp and remained below its present level until about 3000 2000 bp the comparison between the model sea level curve and the archaeological observations also enable to conclude that the average rate of vertical tectonic movement for the last 8000 years at the carmel coast israel has been less than 0 2 mm year q 2001 elsevier science b v all rights reserved

video based nearshore bathymetry estimation in macro tidal environments abstract video based depth inversion through the linear dispersion relation for free surface waves using the cross spectral correlation analysis cbathy holman et al 2013 is applied for the first time in a highly energetic macro tidal environment in the south west of england at porthtowan this application of cbathy reveals two main issues 1 inaccurate depth estimations on inter camera boundaries when multiple cameras are used and 2 significantly less accurate depth estimates over the whole domain during spring tide compared to neap tide inaccuracies of around 35 of the local depths are found during spring tide these two issues are not only important in macro tidal environments the camera boundary issue has been reported in numerous video camera sites and the deviation in accuracy during tidal levels is a function of the tidal range in combination of the vertical camera position to overcome the two issues a camera boundary solution and a floating pixel solution meaning moving pixels in a horizontal plane as function of the tidal elevation are proposed here with the modifications cbathy is capable of estimating depths in the sub tidal zone with an accuracy in the order of 10 of the local depth irrespective to the local tidal regime however for the very upper part of the beach face less accurate results are found due to the reduced validity of the linear dispersion relation in that region due to the non linear behaviour of breaking waves and wave current interactions the improvements persist across all bathymetry survey campaigns at porthtowan and when compared to other well known argus video system sites the importance of the floating pixels is apparent

field investigation of three dimensional flow structure at stream confluences 2 turbulence stream confluences are among the most highly turbulent locations in fluvial systems this paper examines the three dimensional structure of turbulence at three stream confluences in east central illinois the analysis focuses on the characteristics of turbulence both within the shear layer and in the ambient flow results show that at the upstream end of each confluence the shear layer occupies a limited portion of the flow cross sectional area but turbulence kinetic energy within this layer is 2 3 times greater than the turbulence kinetic energy of the ambient flow which has turbulence characteristics similar to those for flow in straight channels turbulence within the shear layer can be characterized as quasi two dimensional in the sense that large scale turbulence generated by transverse shear is predominantly two dimensional whereas small scale turbulence associated with bed friction is three dimensional spectral analysis suggests that the structure of fluid motion within the shear layer differs for confluences with symmetrical versus asymmetrical planforms the shear layer dissipates rapidly as flow enters the downstream channel even though a well defined mixing interface persists at downstream locations

lake level changes and hominin occupations in the arid turkana basin during volcanic closure of the omo river outflows to the indian ocean in the east african rift the western margin of lake turkana northern kenya exposes mio plio pleistocene lake sediments with dated volcanic horizons constraining basin dynamics at the astronomical time scale since the late pliocene coastal archaeological sites have formed within the lacustrine dynamics here lake levels are reconstructed from 2 4 to 1 7 ma using sedimentary facies and water depth controlled sediment association the lacustrine stratigraphy is measured with a total station and cyclostratigraphy is derived from tephrochronology the water depths are evaluated from paleochemical properties of lake sediments analyzed by inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry our reconstruction highlights that lake turkana rose during 100 ka insolation eccentricity maxima periods in response to higher monsoonal inputs of the omo river however lake turkana also expanded through an insolation minimum at 2 17 1 95 ma this asynchronous lake phase coincides with volcanic closure of the omo river and lake turkana outflow sill to the east and the indian ocean an archaeological hiatus occurs during this endorheic lake phase and alkalinity increases at the beginning of the hiatus the lake rose again during insolation eccentricity maxima at 1 9 1 7 ma and a new outflow sill opened to the west and the nile basin hominin coastal occupations return during this exorheic freshwater lake phase

microwave radar cross sections and doppler velocities measured in the surf zone 1 the relationship between microwave imaging radar measurements of fluid velocities in the surf zone and shoaling breaking and broken waves is studied with field observations normalized radar cross section nrcs and doppler velocity are estimated from microwave measurements at near grazing angles and in situ fluid velocities are measured with acoustic doppler velocimeters advs joint histograms of radar cross section and doppler velocity cluster into identifiable distributions the nrcs values from pixels with large nrcs and high doppler velocities 2 m s decrease with decreasing bore height to the shoreline similar to scattering from a cylinder with decreasing radius the doppler velocities associated with these regions in the histograms agree well with theoretical wave phase velocities radar and adv measurements of fluid velocities between bore crests have similarly shaped energy density spectra for frequencies above about 0 1 hz but energy levels from the radar are an order of magnitude higher than those of the adv data instantaneous interbore doppler velocities are correlated with adv measured fluid velocities but are offset by 0 8 m s this offset may be due to bragg wave phase velocities wind drift range and azimuth sidelobes the finite spatial resolution of the radar and differences between mean flows measured at the surface with radar and flows measured below the surface with advs shoaling and breaking waves measured through radar grating lobes significantly affect both the doppler velocities near the edges of the images and the scattering from the rear faces of waves causing large doppler velocities to be observed in these regions

numerical representation of rainfall field in basins of the upper jordan river and of the yarmouk river a non linear complex rain elevation regression model is proposed for the numerical representation of rainfall field in an area with complex plain mountainous topography non uniform distribution of rain gauge network and scarce data of observations the model is applied to basins of the upper jordan river of the lake kinneret and of the yarmouk river in which the major flow of the jordan river is formed the model is implemented in two steps 1 study of the rainfall field based on the average long term climatic data its description by the function of elevation and other factors and optimization of model parameters normalized coefficients of the taylor series and 2 estimation of rainfall in each historical year using the available data less complete and irregular than climatic data as well as a priori known parameters the basic hypothesis is inter annual stability of the model parameters as a necessary primary stage the upper jordan river lake kinneret basin and the yarmouk river basin were divided respectively into seven and five regions considering the specific regional relationships between the mean annual rain depth and elevation it occurred that both basins are represented by a common system of rain elevation curves as a single rain field where the mean annual rain increases with altitude and decreases from west to east and from north to south for each region the parameters of the model were optimized as a base for estimating the annual month rain mean or yearly volume depth in each point of grid in each basin sub basin or in the whole watershed the necessary condition is numerical presentation of the topography derived rain rates can serve as fundamental input data for numerical modeling of surface and groundwater flow this method can be applied to other areas at different temporal and spatial scales

beach wizard nearshore bathymetry estimation through assimilation of model computations and remote observations article i nfo a data model assimilation method called beach wizard is presented with which the nearshore subtidal bathymetry can be accurately estimated based on video derived observations of wave roller dissipation and variation of the intertidal shoreline and or radar derived observations of wave celerity using many consecutive images these observed properties are compared with numerical model results and through a simple optimal least squares estimator approach the estimated bathymetry is adjusted gradually for each image in order to improve the fit between model output and observations the key advantages of the technique are that it is based on multiple sources of information i e different remote sensors and or data products depends on only a few free parameters to which the model results are insensitive and shows good skill herein the technique is applied to a synthetic case and two sets of field data from sites at duck nc usa and egmond the netherlands the method which may be extended with observations of other properties from other sources than the three described in this paper can deliver coastal state information i e simultaneous updates of bathymetry waves and currents with high temporal and spatial resolution and can be used in conjunction with or instead of in situ measured data

the rate of pleistocene subsidence and sedimentation in the hula basin as compared with those of other time spans in other israeli tectonic regions absolute dating of quaternary sediments in the hula basin northern israel by means of radiocarbon and 230th 234u gives the rate of subsidence of the basin the rate of sedimentation which can be obtained by adding the calculated compaction is quite a bit higher from the hula basin and other parts of the country it is evident that different rates of subsidence and vertical displacements are obtained for different time spans rates become higher as the time span becomes shorter and the age younger rates calculated for time spans since the neogene since the quaternary and for the last decades are on the order of magnitude of 10 1 mm y 100 mm y and 101 mm y respectively

constraints on pleistocene pluvial climates through stable isotope analysis of fossil spring tufas and associated gastropods kharga oasis egypt abstract stable isotope analyses of fossil spring carbonates tufas and freshwater gastropods melanoides tuberculata from the currently hyperarid western desert of egypt indicate that this region received enough precipitation to support a small perennial lake during the height of the oxygen isotope stage 6 5e pluvial event and a substantial volume of spring discharge during prior pluvial phases tufa and gastropod oxygen isotope ratios are generally low relative to modern precipitation in the region confirming that the majority of pleistocene pluvial precipitation came from an atlantic source as determined by previous workers mean tufa 13c 2 pdb suggests a significant proportion of c4 vegetation in the recharge area of the tufa depositing springs while the paucity of tufas with 13c greater than 0 suggests that equilibrium between spring water and atmospheric co2 represented an endpoint for the evolution of spring water carbon though spring carbonate deposition requires a substantial increase in humidity in central egypt relative to modern conditions high variation in tufa 18o up to 4 within individual stratigraphic units as well as positive covariance between tufa carbon and oxygen isotope ratios reflect significant effects of evaporation on spring water during tufa formation similarity in 18o and 13c values of tufas from different stratigraphic units indicates that climatic conditions did not vary significantly among pluvial phases recorded by spring carbonate deposition the lack of substantial carbonate formation at tufa localities during the holocene pluvial phase however suggests that tufa deposition represents substantially wetter conditions than have existed during holocene time

multivariate analysis and interpretation of the hydrochemistry of a dolomitic reef aquifer northern italy regionalization based on multivariate statistical analyses of hydrochemical data and environmental isotopes proved most successful in differentiating groundwater of different hydrogeological origins within the sasso lungo dolomitic mountain stock northern italy the approach used chemical and isotopic data to evaluate hydrologic properties normally determined by more traditional techniques from field and laboratory studies of 19 hydrochemical variables measured at 46 sampling points three distinct groups of water types were differentiated in close agreement with hydrogeological evidence namely 1 pure sciliar dolomite water 2 water from volcanic deposits and 3 mixed water from sciliar dolomite and volcanic deposits environmental isotopes are used to support hydrogeological observations arid the hydrochemical analyses and also to provide valuable additional information for further distinction between hydrogeological subsystems the data show that the dolomite aquifer discharges from two main subsystems 1 relatively young shallow to moderately deep waters in the central part of the reef stock and 2 older groundwater discharging at the rims of the reef

multiphase reverse vertical tectonic displacement across major faults in northern israel abstract geological investigations in northern israel supported by recent seismic interpretation of offshore data indicate that the major fault systems there have undergone several tectonic phases since the mesozoic it is suggested that the vertical displacements related to the younger phase of neogene to recent age are in a reverse direction to those of the mesozoic and older phases

observations of steady longshore currents in the surf zone abstract steady surf zone longshore currents and directional properties of the incident wave field were measured on a beach with nearly straight and parallel depth contours selected data were processed into 64 segments each of 68 2 min duration irregularly spaced throughout an 18 day period a wide variety of incident wave and longshore current conditions were observed the radiation stress spectrum sxy f was estimated from a slope array and two current meters located seaward of the surf zone in many cases the total radiation stress sxyt sxy f f contains important contributions from a wide range of frequencies in a few instances sea and swell approach the beach from different directions quadrants resulting in a new zero sxyt the strong shears and direction reversals of the longshore current that could conceivably occur in this circumstance were not observed an eof decomposition of the mean longshore current pattern shows that most 90 of the current spatial variation in the 64 runs is

last glacial holocene temperatures and hydrology of the sea of galilee and hula valley from clumped isotopes in melanopsis shells abstract the carbonate clumped isotope 47 thermometer was applied to fresh water snails melanopsis spp grown in the waters of the sea of galilee and hula valley in the north of israel modern shells grown at known temperatures agree with the 47 t calibration of zaarur et al 2013 fossil melanopsis shells from 2 locations gesher bnot ya aqov at the southern tip of the hula valley and the sea of galilee provide a temperature record for the region during the time interval of the past 20 kyrs glacial temperatures are 5 c cooler than mid holocene and 3 c cooler than modern similar to other records in the region these 47 derived temperatures are combined with 18o of the shell carbonate to calculate the oxygen isotopic composition of the habitat waters contrary to global trends and other regional records reconstructed 18owater values increase from the late glacial through the holocene this reversed signal reflects a decrease in the relative contribution of snowmelt to the watershed post lgm and a transition to a more rain dominated inflow a fairly constant difference in 18owater values between the hula valley and sea of galilee waters suggests that the hydrological relationship of the two water bodies had remained constant with the temperature changes playing only a minor role in the extent of evaporation of the sea of galilee relative to the hula

video derived near bed and sheet flow sediment particle velocities in dam break driven swash abstract this short communication considers a video based approach to quantify near bed and sheet flow swash zone sediment particle velocities over a mobile bed in a laboratory setting and relate the profile shape to sheet thickness and a velocity that can be measured outside the sheet layer by for instance a current meter near bed high speed imagery was recorded during a dam break driven swash event in a flume with optically clear walls repeated swash events for two different median sediment sizes were tested optical current meter ocm analysis was applied to bed parallel image time stacks extracted at elevations from below the at rest bed to within the lower water column ocm results were compared to in situ velocity measurements where possible obtained with an acoustic doppler profiling velocimeter adpv ocm results compared well with adpv measurements for moderate suspended sediment concentrations based on visual observation sediment concentrations were not measured too high of a sediment concentration over saturated the image and did not provide distinct sediment particle trajectories in a consistent direction for ocm analysis this saturation occurred during uprush for both sediment sizes too little of a sediment concentration provided an inadequate number of sediment particle trajectories to track such as during flow reversal for the coarser sediment for coarser sediment backwash velocities were well resolved in ocm analysis with velocities comparing well correlation coefficient 0 8 to adpv estimates the dimensionless backwash sheet flow sediment particle velocity profile normalized by the velocity at the top of the sheet scaled with the dimensionless elevation normalized by the sheet layer thickness to the 0 62 power with 95 confidence intervals for the exponent ranging from 0 47 to 0 76

rip current types circulation and hazard abstract rip currents are narrow and concentrated seaward directed flows that extend from close to the shoreline through the surf zone and varying distances beyond rip currents are ubiquitous on wave exposed coasts each year they cause hundreds of drowning deaths and tens of thousands of rescues on beaches worldwide and are therefore the leading deadly hazard to recreational beach users the broad definition above masks considerable natural variability in terms of rip current occurrence in time and space flow characteristics and behaviour in particular surf zone rip currents have long been perceived as narrow flows extending well beyond the breakers flushing out the surf zone at a high rate exit flow circulation regime while more recent studies have shown that rip flow patterns can consist of quasi steady semi enclosed vortices retaining most of the floating material within the surf zone circulatory flow circulation regime building upon a growing body of rip current literature involving numerical modelling and theory together with emergence of dense lagrangian field measurements we develop a robust rip current type classification that provides a relevant framework to understand the primary morphological and hydrodynamic parameters controlling surf zone rip current occurrence and dynamics three broad categories of rip current types are described based on the dominant controlling forcing mechanism each category is further divided into two types owing to different physical driving mechanisms for a total of six fundamentally different rip current types hydrodynamically controlled 1 shear instability rips and 2 flash rips which are transient in both time and space and occur on alongshore uniform beaches bathymetrically controlled 3 channel rips and 4 focused rips which occur at relatively fixed locations and are driven by hydrodynamic processes forced by natural alongshore variability of the morphology in both the surf zone and inner shelf zone and boundary controlled 5 deflection rips and 6 shadow rips which flow against rigid lateral boundaries such as natural headlands or anthropogenic structures for each rip current type flow response to changes in hydrodynamic and morphologic forcing magnitude is examined in regard to velocity modulation and changes in circulation regime providing key force response relationships of rip currents we also demonstrate that in the real world rip currents form through a mixture of driving mechanisms and the discrete rip types defined in fact form key elements in a wide and complex spectrum of rip currents on natural beaches it is anticipated that this rip current type classification will serve as a resource for coastal scientists and non specialists with an interest in the rip current hazard and as a platform for future rip current studies finally we suggest some important future research directions highlighting the need for coastal and beach safety communities to collaborate in order to improve rip current education and awareness

quantification of sand bar morphology a video technique based on wave dissipation a technique is presented to remotely measure the scales and morphology of natural sand bars based on the preferential dissipation of wind waves and swell over the crests of the bar photographic or video images are recorded and statistical uncertainties associated with incident wave height modulations removed by averaging time exposures ground truth testing of the technique was carried out as part of the superduck experiment in october 1986 the time exposures generally provided a good mapping of underlying morphology allowing detection of the bar and determination of cross shore and longshore length scales however during high waves persistent surface foam obscures the relationship of image intensity to local dissipation modeled theoretically by dissipation of a random wave field and an enhancement technique of image differencing must be done to remove the bias errors in the estimate of bar crest distance from the shoreline are generally less than 35 but this value depends on the geometry of the particular bar logistic simplicity and quantitative capabilities make this technique very attractive

quantifying riverine surface currents from time sequences of thermal infrared imagery 1 river surface currents are quantified from thermal and visible band imagery using two methods one method utilizes time stacks of pixel intensity to estimate the streamwise velocity at multiple locations the other method uses particle image velocimetry to solve for optimal two dimensional pixel displacements between successive frames field validation was carried out on the wolf river a small coastal plain river near landon mississippi united states on 26 27 may 2010 by collecting imagery in association with in situ velocities sampled using electromagnetic current meters deployed 0 1 m below the river surface comparisons are made between mean in situ velocities and image derived velocities from 23 thermal and 6 visible band image sequences 5 min length during daylight and darkness conditions the thermal signal was a small apparent temperature contrast induced by turbulent mixing of a thin layer of cooler water near the river surface with underlying warmer water the visible band signal was foam on the water surface for thermal imagery streamwise velocities derived from the pixel time stack and particle image velocimetry technique were generally highly correlated to mean streamwise current meter velocities during darkness r2 typically greater than 0 9 and early morning daylight r2 typically greater than 0 83 streamwise velocities from the pixel time stack technique had high correlation for visible band imagery during early morning daylight hours with respect to mean current meter velocities r2 0 86 streamwise velocities for the particle image velocimetry technique for visible band imagery had weaker correlations with only three out of six correlations performed having an r2 exceeding 0 6

bathymetry correction using an adjoint component of a coupled nearshore wave circulation model tests with synthetic velocity data 1 the impact of assimilation of wave averaged flow velocities on the bathymetric correction is studied in tests with synthetic model generated data using tangent linear and adjoint components of a one way coupled nearshore wave circulation model weakly and strongly nonlinear regimes are considered featuring energetic unsteady along beach flows responding to time independent wave averaged forcing due to breaking waves it is found that assimilation of time averaged velocities on a regular grid mimicking an array of remotely sensed data provides sensible corrections to bathymetry even though the wave data are not assimilated flow velocity assimilation utilizes adjoint components of both the circulation and wave models the representer formalism allows separating contributions of these two components to the bathymetric correction in a test case considered involving a beach with an alongshore varying bar the adjoint wave model contribution was mainly to determine the cross shore position of the bar crest the adjoint circulation model provided an additional contribution mostly adding to alongshore variability in the shape of the bar the array mode analysis reveals that there are very few modes that can be effectively corrected given the assumed data error level bathymetry perturbations associated with these modes are a mixture of near coast intensified modes as well as modes extending their influence to deep water along the background wave characteristics additional tests show the utility of different observational arrays in providing the bathymetric correction

modelling precipitation streamflow processes in karst basin the case of the jordan river sources israel summary a system approach daily precipitation streamflow model was developed for both the base and the surface flow components of large scale karst basins long term streamflow data were separated to baseflow and surface flow using the recursive digital filter method which provides time series for model calibration the hydrological model for karst environment hymke includes attributes to large scale preferential flow that recharge the groundwater and solve the problem of uncorrelated baseflow and surface flow in a karst environment hymke was applied simultaneously to the three major tributaries of the upper catchment of the jordan river which originate in the karstic region of the hermon mountain northern israel it was verified by comparing the calculated surface flow and baseflow with the daily time series of the baseflow separation procedure and demonstrated good agreement of both the surface r2 0 6 and baseflow r2 0 77 components of each stream

plio pleistocene marine continental correlation using habitat indicators from olduvai gorge tanzania abstract reconstructions of plio pleistocene habitats and lake levels from a brief interval 200 000 yr of hominid bearing sediments from bed i and lower bed ii olduvai gorge tanzania are for the first time integrated with climatic data from the deep sea in order to examine the effect of largescale climatic events in east africa the period of densely vegetated habitats and wet conditions at olduval at 1 82 myr shows a best fit with a period of northern hemisphere warming as evidenced by oxygen isotopes from deep sea core v28 239 from the western pacific this environmental response is similar to that witnessed in east africa during the period of warming climates associated with deglaciation at 10 000 8 000 yr

timing the transport of water through the upper vadose zone in a karstic system above a cave in israel chemical and isotopic analysis of karst water dripping over a one year period from seeps in a cave above the cenomanian aquifer in the judea hills of israel lead to several conclusions i the tritium ages and the chemical composition of water from different seeps in a karstic cave vary greatly ii the reservoirs in the upper part of the vadose zone hold water for up to several decades iii some of the cave seeps are mixtures of the old and more recent meteoric water from paths of different length iv the history of storm events can only be traced in some of the seeps v for most dripping seeps there is no immediate response of seepage discharge to the rainfall intensity and quantity i e the seepage discharge is fairly constant

the decline of the early neolithic population center of ain ghazal and corresponding earth surface processes jordan rift valley abstract ain ghazal is among the earliest large population centers known in the middle east a total of four major stratigraphic cultural units have been identified 1 the oldest middle pre pottery neolithic b mppnb unit 10 2 to 9 5 cal ka bp clearly corresponds with the early holocene maximum dead sea levels 2 the second unit consists of late pre pottery neolithic b lppnb in situ walls and hearths 3 in the subsequent ppnc 8 9 to 8 6 cal ka bp the population density at the settlement drops dramatically which corresponds with a significant drop in the dead sea level 4 the 4th stratigraphic unit is characterized by the yarmoukian rubble layer additionally there is evidence for a previously unrecognized use of the site by chalcolithic pastoralists sedimentological analyses reveal a constant increase in dust from a remote source during the entire human occupation period which correlates well with the detectable drops in climatic humidity from the dead sea as the major focus of this study we can now rule out previous notions that the yarmoukian rubble layer could have been produced by catastrophic slope scale gravitational movements to this point it appears that the neolithic mega site was abandoned due to a climatic aridification

the hydrology of the jordan tributaries israel hydrographic and isotopic investigation abstract nahal dan nahal snir and nahal hermon are the three principal tributaries of the jordan river all three are spring fed and appear to derive their discharges from the same regional groundwater aquifer the behaviour of this aquifer is examined by hydrograph separation and multivariate time series analysis of discharge and rainfall records and by investigation of 18 o and tritium records hydrograph separation gives base flow recession constants of 11 20 months and in addition n snir and n hermon show an interflow recession of 1 month the dual reservoir system for these two tributaries is confirmed by time series analysis 18 o data distinguish the different catchments for the springs and support the idea that interflow occurs in the near surface part of the regional groundwater reservoir tritium data illustrate the inhomogeneity of the karstic reservoir assuming well mixed conditions the difference in behaviour between tritium records for rainfall and the tributaries is used to estimate the age distribution of water in the reservoir at any time 50 of the storage is less than 1 yr old and 90 is less than 3 yr old

morphometric and geomorphic approaches for assessment of tectonic activity dead sea rift israel a series of 31 short parallel steep channels mostly of first or second order occur at intervals of 300 500 m along 16 km of the western margin of the northern dead sea rift israel the analysis of tectonic and geometric activity along the marginal faults between the various segments is based on morphometric parameters such as sinuosity of the mountain front channel gradients drainage basin elongation ratio planimetric ratio facet areas hypsometric curves and integrals longitudinal profiles of the channels were studied in relation to the underlying lithology and the presence of marginal faults despite the great differences in climatic and geomorphologic settings comparison with other studies worldwide showed morphometric values similar to other tectonically active regions the southern segments of the study area which face the hula deep depression indicate enhanced geomorphic and tectonic activity the northern segment proved dissimilar to the others and is explained by its different tectonic setting six sedimentary fan like units composed of polymictic conglomerates were deposited along the mountain piedmont at the channel mouths the units were dated by osl k ar and archaeology to 1 1 ma q 1 and q 1 1 0 56 ma unit q 2 120 ka unit q 3 and 10 ka units q 4 and qs the morphology and structure of the sedimentary units indicate pulses of depositional activity followed by periods of quiescence and calcicsoil development no major faulting occurred along the naftali escarpment during the upper pleistocene despite the high tectonic morphometric values obtained for the study area the marginal faults displaced unit q 2 during the mid pleistocene and since then tectonic activity has shifted from the western marginal faults eastward to younger faults deeply buried in the center of the graben the field data calibrate the morphometric analysis carbonate limestone and dolomite hillslopes developed in the mediterranean climate have maintained active tectonic class morphology since the last major faulting events during the mid pleistocene

spatial and temporal structure of shear layer turbulence at a stream confluence 1 the shear layer that develops at the interface between converging flows is a prominent but poorly understood hydrodynamic feature at stream confluences to examine the spatial and temporal characteristics of turbulence and coherent turbulent structures within a shear layer three dimensional velocity measurements were obtained at a small stream confluence in illinois using two acoustic doppler velocimeters spaced at various separation distances results indicate that coherent structures can be readily identified through cross correlation analysis of the velocity time series for different measurement locations maximum correlations decrease relatively slowly over short separation distances but decrease rapidly for separation distances greater than about 2 times the flow depth convective velocities of coherent structures derived from the correlation analysis differ from local mean velocities and from spatially averaged mean velocities indicating that coherent structures evolve as they are transported along the shear layer a finding consistent with dye tracing experiments despite this evolution correlation and spectral analyses indicate that the frozen turbulence hypothesis holds for frequencies corresponding to length scales of at least some shear generated coherent vortices a domain of quasi two dimensional turbulence energy at low frequencies appears to be associated with large scale intrusions of fluid from one stream into the other along the mixing interface

offshore controls on nearshore rip currents 1 the rip current field resulting from the transformation of surface gravity waves over offshore submarine canyons is studied employing a wave transformation model and a wave induced circulation model over observed bathymetry we find that wave height variations associated with undulations in the canyon contours cause rip current circulation cells with alongshore spacing of o 100m even though the nearshore bathymetry displays no variations at these length scales further the predicted rips correspond to observed rip currents during the nearshore canyon experiment ncex motivated by these results we study the relationship between o 100 m scale variations in offshore bathymetric contours and the resulting rip current field in the nearshore to isolate the roles of possible bathymetric features we construct a series of idealized case studies that include site characteristics found at ncex that are conducive of rip current development such as a curved shoreline an offshore submarine canyon and undulations in the canyon contours our results show that the first two components are unable to produce the observed short scale circulation systems while wave refraction over undulations in the canyon walls at length scales of o 100 m provides a sufficient disturbance to generate alongshore wave height variations that drive multiple rip currents for a variety of incident wave conditions rips are not generated when the wave period is short or when the angle of incidence is large analysis of the alongshore momentum balances further demonstrates that the rip current locations are also strongly influenced by inertial effects hence nonlinear processes are important within the rip current circulation cell and we find that nonlinear advective acceleration terms balance a large portion of the driving alongshore gradient in the mean water surface elevation in the vicinity of the rip currents with bottom friction accounting for the remainder away from the rips the balance is between the wave forcing and the pressure gradient outside the surf zone and wave forcing and bottom friction inside the surf zone as expected

an isotopic study of a fluvial lacustrine sequence the plio pleistocene koobi fora sequence east africa stable isotopic analyses of plio pleistocene and modern sediments in the fluvial lacustrine system occupying the turkana basin east africa provide constraints on the paleoenvironmental and diagenetic histories of the pliocene through the recent sediments in the basin the 13c values for carbonates in lacustrine sediments range from 15 to 22 relative to pdb depending on the varying proportions of co2 from the atmospheric reservoir and from various metabolic sources the 18o values of carbonates in lacustrine sediments indicate that the isotopic composition of paleolake water varied by over 10 from the pliocene to the present the 13c values for pedogenic carbonates record paleoccologic variations and suggest that c4 plants did not become well established in the preserved depositional parts of the basin until about 1 8 myr ago the 18o values pedogenic carbonates suggest a range of over 10 for the isotopic composition of soil water during this interval they also suggest a period of major climatic instability from about 3 4 to 3 1 myr and at about 1 8 myr together the 13c and 18o values of pedogenic carbonates indicate that the present conditions are as arid and hot as any that had prevailed during deposition of these plio pleistocene sediments

a new 36cl hydrological model and 36cl systematics in the jordan river dead sea system the recent breakthrough in our ability to detect the radioactive isotope 36cl half life t 301 000 yr at natural levels by accelerator mass spectrometry1 allows the processes of salination of water systems to be studied in a new way by distinguishing the chloride content originating in young rainwaters and their subsequent evaporation from that generated by the leaching of ancient rocks results for the jordan river dead sea system show that the amount of chloride leached from rocks ranges from 70 in source springs to 90 in water bodies downstream furthermore the amount of water left after evaporation decreases from 50 in the source springs to 20 in the intermediate lake kinneret in the terminal dead sea 99 of the stable chloride originates from ancient rocks and evaporite formations while 80 of its 36cl content is of meteoric origin using 36cl measurements we estimate the accumulation time of the dead sea salt to be 19 000 25 000 yr

thermal infrared multipath reflection from breaking waves observed at large incidence angles the infrared signature of breaking waves at large incidence angles was investigated using laboratory experiments and a radiometric model infrared imagery of the water surface at incidence angles greater than 70 shows multipath reflections for both spilling and plunging waves generated using a programmable wave maker for the spilling breakers the multipath signature was initially distinct from the breaking wave front roller signature but then merged to create a single large bright distributed target for the plunging breakers the roller and multipath signatures overlapped from the inception of breaking the radiance of the multipath reflection was higher than the surrounding water for simulated cold sky conditions and lower for a simulated warm sky a specular double reflection model successfully predicted the presence of multipath reflection but the magnitude was sensitive to small uncertainties in geometry wave slope and input temperatures the results show that multipath reflection from breaking waves is characteristic of large incidence angle infrared measurements and increases the area and magnitude of the infrared signature of breaking waves compared to the background

palaeoclimates at lake turkana kenya from oxygen isotope ratios of gastropod shells climatic changes in the plio pleistocene of east africa during the evolutionary development of early man have been identified only in their broadest outlines a variety of palaeontological1 3 and geochemical4 techniques have already been applied to the study of palaeoclimates in this area but the use of stable oxygen isotope ratios so helpful in marine palaeoclimatology has not been fully exploited5 6 the frequent occurrence of well preserved mollusc shells in the sedimentary column at lake turkana provides a sensitive oxygen isotope record varying over a range of 7 which can be interpreted in terms of evaporative concentration of the heavier oxygen isotope in waters of the closed lake alternating with isotopically lighter freshwater when the lake has been open i report here the results of a study of the 18o 16o ratios of three species of gastropods from the sediments of the koobi fora region of lake turkana and evaluate how the technique might be applied to the study of the palaeoclimates of other tropical lakes

quantification of swash flows using video based particle image velocimetry understanding of fluid flows and sediment transport in the foreshore has been severely hampered by the difficulty of obtaining swash flow velocity measurements in this dynamic and extremely shallow region we present a digital imaging method known as particle image velocimetry piv to quantify the horizontal flow structure of swash this technique exploits similar patterns of image intensity in multiple images sampled sequentially to identify spatial offsets corresponding with maximum correlations between image subregions these offsets are used in conjunction with the sampling interval to derive velocity vectors describing the horizontal flow structure pre processing methods to geo rectify oblique imagery to a planar surface and post processing methods of correcting spurious vectors are described the piv method overcomes many of the limitations of in situ sampling of swash flows and is shown consistent with results from a previously tested remote sensing technique for measuring swash edge velocities in general this technique provides a unique capability for spatially extensive and well resolved quantification of swash flows

the spatial and temporal variability of sand bar morphology the spatial and temporal variability of nearshore sand bar morphology is quantified using a unique data set spanning 2 years the data consist of daily time exposure images of incident wave breaking on an open coast sandy beach which may be used to infer bar morphology lippmann and holman 1989 the morphology in each image is classified into an eight state morphologic scheme in which bars are uniquely defined by four independent criteria the most frequently observed morphologies are the longshore periodic rhythmic bars observed in 68 of the data linear bars occur under highest wave conditions h s 1 78 m and are unstable mean residence time 2 days shore attached rhythmic bars are the most stable mean residence time 11 days and generally form 5 16 days following peak wave events non rhythmic three dimensional bars are very transient mean residence time 3 days eighty seven percent of transitions to lower bar types defined in text occurred one state at a time supporting our selection of the ordering of states and suggesting the suitability of a sequential morphology model transitions to higher states occurred under rising wave energy and were evenly spread among the possible higher states with more substantial changes in morphology resulting from larger wave increases this suggests that up state erosional transitions based on offshore bar migration are better described by an equilibrium model where response is better correlated with incident wave energy than with preceding morphological state time exposure images were also digitized to yield quantitative estimates of bar crest location as a function of longshore distance principal component analysis was used to decompose bar position into two dimensional linear and three dimensional longshore variable components cross shore linear bar position ranges 50 m about the 2 year mean 27 m standard deviation and dominates bar variability 74 6 three dimensional bar structure accounts for 14 of the variance 12 m standard deviation changes in incident wave height precede cross shore bar migration by less than 1 day changes in longshore variability are inversely correlated to changing wave conditions with bar morphology becoming linear rapidly during storms on time scales of less than 1 day evolution to significantly three dimensional structure typically occurs over 5 7 days following peak wave events

video based depth inversion techniques a method comparison with synthetic cases abstract applications of video based depth inversion in the near shore coastal environment are growing in numbers video based capabilities in nearshore monitoring are improving and coastal monitoring programs are expanding due to greater availability and reduced costs video derived beach state indicators such as beach width bar position and wave and current parameters are supplemented by accurate depth estimations through inversion video based depth inversion knows two main approaches a spectral and temporal method of celerity estimation the two methods have so far never been compared as video systems are often tailored for the chosen celerity estimation method here a spectral and temporal method are compared using controlled synthetic datasets obtained using the serre1d boussinesq model to estimate celerity and invert depth the assessment is carried out on a set of wave boundary conditions with over linear and barred bottom profile both methods invert depth with a similar accuracy for the most realistic jonswap cases an evident correlation is found between wave skewness non linearity and depth estimation error linked to the limits of the linear dispersion relation a residual sensing error is linked to method based parameters and a changing wave shape as incident waves propagate inshore the inversion error can be reduced significantly including a wave height dependent non linear correction importantly a method based error is introduced for the temporal method to increase the suitability for data assimilation likewise the spectral method has its own existing depth error estimation to feed into the kalman filter however these method based error estimates show very weakly or no relation to the observed error between estimated cross shore profile and bottom profile used for the model input

the younger dryas episode and the radiocarbon chronologies of the lake huleh and ghab valley pollen diagrams israel and syria pollen diagrams from the former lake huleh in israel and the ghab valley in syria are the most important records of vegetation change in the levant during the lateglacial and early holocene environmentally deterministic explanations of the development of agriculture in this region therefore rely on the accuracy of the diagrams radiocarbon chronologies radiocarbon results at both sites are subject to large reservoir effects however the 14c content of modern water from the huleh basin implies that the huleh radiocarbon results require corrections of up to 5500 14c years a revised chronology of the latest huleh pollen diagram is proposed this is consistent with the regional vegetation sequence recorded in eastern mediterranean marine sediments the regional sequence also provides the most plausible chronology for the ghab pollen diagrams

the initiation of northern hemisphere glaciation for well over a century scientists have speculated that variations in the atmospheric concentration of radiatively important trace gases such as carbon dioxide could control the earth s climate e g arrhenius 1 896 recent observations of significant glacial interglacial variation in atmo spheric co2 in ice cores put this idea on a firm observational as well as theoretical footing e g barnola et ai1 987 in this century as atmospheric co2 levels creep steadily upwards in response to the burning of fossil fuels and forests the specter of manmade global climate change looms before us ipcc 1990 a possibility that has heightened interest in the natural variability of climate in the past in particular the 3 c warming pre dicted for the next century has stimulated interest in past warm climates such as the middle pliocene around 3 0 million years ma ago an interval that has often been invoked as a greenhouse world budyko et al 1985 in this paper the climate transition from the warm mid pliocene around 3 2 ma to the onset of northern hemisphere ice ages around 2 4 ma is examined evidence for the initiation of significant northern hemisphere glaciation is examined as well as how this event affected climate around the globe while the cause of individual glacial interglacial oscillations is tied to milankovitch variations in the earth s orbit around the sun e g imbrie et ai 1 992 these insolation changes cannot account for the long term cooling trend which culminated in northern hemisphere glaciation in the final section of this paper mechanisms of long term climate change

long continental records of climate an introduction abstract the symposium on long continental records presented new information on past climates on land it seems that throughout the last 2 5 million years the climate in the middle latitudes changed in the same complex fashion as during the better known late pleistocene and holocene times over 40 interglacial glacial shifts took place during this interval out of those 40 10 12 glacials were markedly stronger and or longer lasting than the others the apparently abrupt shifts from interglacials to glacials were probably gradual oscillatory coolings interrupted by warming episodes in that respect the detailed anatomy of the past climate changes does not differ substantially from the climate oscillations documented by instrumental weather records in the last two centuries the pronounced expansions of dry and cold steppes on land were accompanied by corresponding increases of the ice volume indicated by the oxygen isotope ratio the two exceptions occurred around 1 4 ma ago and 1 6 ma ago the reason for this discrepancy is not known by far the most expressed change of land environments occurred at about 2 4 ma ago

drainage development and incision rates in an upper pleistocene basalt limestone boundary channel the sa ar stream golan heights israel abstract long term fluvial incision processes and corresponding geomorphic evolution are difficult to quantify especially in complex systems affected by lithological and tectonic factors volcanic landscapes offer the most appropriate environment for the study of landscape evolution as there is a clear starting time of formation and the lithology is homogenous in the present study we aim to 1 analyse the interplay of construction and incision processes throughout eruptive activity 2 study fluvial erosion processes 3 analyse sedimentary and volcanic lithological responses to channel erosion and 4 calculate the incision rates in young basaltic bedrock we have integrated existing and new 40ar 39ar ages of lava flows with estimates of channel geometry and tectonic activity and considered process geomorphology concepts to fully understand evolution of a bedrock channel incised at the boundary between basalts and sedimentary rocks with coeval active volcanic processes forcing drainage evolution our findings indicate that the sa ar basin evolution is controlled by 1 rock strength of the mixed lithology 2 alternating cycles of volcanic activity followed by erosion and incision and 3 the plio pleistocene uplift of mt hermon the carbonate slopes composing the southern flank of mt hermon are moderate 18 26 while the basalt slopes deriving from the golan heights are much steeper 26 51 the highly erodible sedimentary rocks at mt hermon s piedmont accelerated river incision shaping a 650 m wide by 100 m deep canyon inside the canyon the steep channel slope 8 6 enables downstream movement of large boulders including autochthonous mega blocks d90 size 2 5 m 24 knickpoints were identified using ds plots developed within a knick zone over a distance of 6 km the brittle and porous structure of the rubbly and blocky interflow layers clinkers interbedded between two massive basalt flows enhances erosion and accelerates scouring of the plunge pool bottom and walls three volcanic phases shaped the sa ar basin 1 the 3 25 ma cover basalt flowed over large areas of the levant and reached up to the northern golan 2 dalwe basalt was emplaced between 1 2 ma and 750 ka from vents including mt qatzaa and mt odem and extended to mt hermon covering sedimentary cuestas 3 ein zivan basalt including the sa ar lava flow the youngest basalt flow known in israel erupted before 110 120 ka and quickly accumulated at least three distinct flows into the deeply incised paleo sa ar canyon refilling the canyon to a height of 50 m rates of incision are consistent with other rivers draining the golan heights the total incision rate of the sa ar channel during the last 760 ka is at least 19 7 cm ka over the past 100 ka the incision rate was 22 30 cm ka and the back erosion of the sa ar highest knickpoint occurred at 68 cm ka our findings reflect the latest evolution history of a special mixed lithology channel developed at the border of a large basaltic province in an active tectonic environment the results suggest that fluvial adjustment of basalt limestone rivers is determined first by the interplay of construction and incision processes throughout alternating cycles of volcanic activity and quiescence the lithology is an extremely important factor determining the type and rate of erosion while the tectonic factor might determine the basin relief and slope the lithological factor accelerates erosion and river incision

vertical profiles of longshore currents and related bed shear stress and bottom roughness the vertical structure of the mean wave driven longshore current over a barred beach is examined on three strong current days during the duck94 experiment and it is found that the bottom boundary layer is well described by a logarithmic profile mean correlation coefficient for all 22 profiles 0 98 the logarithmic profile fits better in the trough where turbulent bottom boundary layer processes predominate than over the bar where breaking wave induced turbulence generated at the surface modifies the profile the surface layer in the presence of waves is well described by adjusting the logarithmic profile for the intermittent presence of water and adding the alongshore component of the mass transport velocity slope of the least squares linear regression between model predictions and observations 1 005 and root mean square rms error of 7 bed shear stresses calculated from logarithmic velocity profiles are equated to a quadratic bottom shear stress formulation the associated bed shear stress coefficients vary by more than an order of magnitude across the surf zone 0 0006 0 012 bottom roughness was measured throughout the nearshore using a sonic altimeter mounted on a moving platform the bed shear stress coefficients are positively correlated with bottom roughness linear correlation coefficient 0 6 a higher linear correlation coefficient 0 8 is obtained by subtracting skin friction from the total bed shear stress

stratigraphy and isotope records of middle and late pleistocene mollusks from a continuous corehole in the hula basin northern jordan valley israel morphological changes in melanopsis shells and the sudden disappearance of viviparus were observed in a continuous core representing about 700 000 yr taken from the l 12 corehole in the hula basin northern jordan valley israel two major events in 18o values are recorded the first at about 435 000 yr b p is accompanied by a shift in 13c values and indicates a shallowing phase with slightly higher evaporation this event is concurrent with the abundant occurrence of a monotypic distorted melanopsis suggesting an ecophenotypic event during deposition of the lake s pleistocene lower lacustrine beds the second major isotopic event is evidenced in the lower part of the section as a gradual depletion in 18o toward the bottom of the corehole minor shifts of 1 20 in the oxygen isotope content along the core may represent changes in the 18o values of the water from glacial to interglacial periods representing the major climatic cycles of the pleistocene five of these cycles were observed along the core

first indications of high slip rates on active reverse faults nw of damascus syria from observations of deformed quaternary sediments implications for the partitioning of crustal deformation in the middle eastern region recent research on rates of crustal shortening within the palmyra fold belt pfb in syria has drawn attention to the possibility that reverse faults near the city of damascus which adjoins the sw pfb have significant slip rates we infer that the damascus fault directly adjacent to the city has developed a throw of 2500 m and report the discovery of the en echelon bassimeh fault with a throw of 1000 m this fault being revealed by warping of the local bedrock and of a terrace of inferred late pleistocene age of the river barada we estimate that this set of faults became active circa 0 9 ma synchronous with changes to the pattern of faulting previously reported farther southwest in the northern jordan valley vertical slip rates on the bassimeh and damascus faults of 1 1 and 2 8 mm a 1 respectively are thus estimated we also infer that large historical earthquakes previously attributed to left lateral faulting farther west on the dead sea fault zone dsfz probably occurred on this set of reverse faults these faults thus represent a significant hazard to the city of damascus our observations indicate that as much as half of the northward motion of the arabian plate relative to the african plate may be absorbed by crustal shortening within the pfb potentially explaining the low slip rate recently measured geodetically on the northern dsfz in western syria

uranium series dating of quaternary deposits abstract this is a review of u series dating methods as applicable to terrestrial sedimentary materials alpha counting techniques allow the dating of carbonates and phosphates with a precision of 5 to 10 over the time range from 1 ka to 350 ka atom counting methods mass spectrometry and ams substantially increase precision and may increase the range problems of contamination and open system behavior are discussed correction for detrital contaminant is demonstrated in the dating of speleothem from a cave in italy

molluscan biostratigraphy of the koobi fora hominid bearing deposits since the discovery1 of late cenozoic hominid bearing deposits in the koobi fora area north kenya a variety of studies2 9 have been undertaken to provide a chronostratigraphical and palaeoenvironmental context for the important palaeoanthropological and early archaeological discoveries1 10 unfortunately although the exposures are areally extensive 1 000 km2 they are broken up into subareas fig 2 these local sections are often difficult to correlate with one another due to intervening bush cover and faulting here i summarize a molluscan biostratigraphical analysis which demonstrates serious stratigraphical miscorrelations between certain local sections including some previously indicated by vertebrate evidence these miscorrelations require substantial revisions to current stratigraphical interpretation of the koobi fora deposits in particular both the suregei and tulu bor tuff horizons actually represent different levels although the tulu bor is considered to overlie the suregei some exposures currently attributed to the tulu bor are actually older than some units previously mapped as the suregei fortunately the stratigraphical miscorrelations reported here do not significantly affect the relative placement of the mollusc faunas reported in a previous evolutionary analysis15 superpositional relationships in the areas from which these faunas were collected mainly collecting areas 102 103 110 123 202 and 203 are unaffected by the miscorrelations reported here

integrated monitoring of the hydro morphodynamics of a beach protected by low crested detached breakwaters the aim of this paper is to propose an integrated low cost system for monitoring the performance of beach defence works during storms for this purpose the site of igea marina northern adriatic sea italy which is protected by low crested detached breakwaters is selected the monitoring system is composed by a video installation for the identification of the shoreline position and of the intertidal bathymetry at high space and time resolution and a 2dh numerical model to reconstruct the hydrodynamics induced by coastal defenses the accuracy of the monitoring system is verified against available measurements of waves and currents performed during a field campaign with acoustic doppler profilers assimilation of data on the shoreline position in 2dh model operatively working is challenging in the improvement of the production of risk maps these show the current intensities and flooded areas during forecasted storms first promising results suggest the possibility of setting up an early warning tool

geological setting and age of the middle paleolithic site of nahal mahanayeem outlet upper jordan valley israel abstract in this paper we present the sedimentary features and the luminescence chronology for nahal mahanayeem outlet nmo an archaeological open air site at the southern margin of the hula basin northern jordan rift valley israel the site is characterized by a lithic assemblage ascribed primarily to the middle paleolithic mousterian tradition and by an excellent preservation of floral and faunal remains six geological units forming the stratigraphic sequence of the site were distinguished unit 6 archaeologically sterile light colored limnic carbonates unit 5 conglomerates of rounded basalt boulders and cobbles forming a hill like topography unit 4 and unit 3 a sequence of similar dark silty sediments attached to and overlaying the conglomerates containing the archaeological horizons of the site unit 2 a number of channels cutting into the top of unit 3 filled with coarse sand and rounded basalt and limestone gravels of fluvial origin and unit 1 a thin sand layer laid down by the present day jordan river covering another unconformity as a result of heavy machinery drainage operations in 1999 the osl age for unit 6 yielded a minimum age older than 460 ka sedimentary features and the embedded fossils suggest that unit 1 can be linked to the early pleistocene gadot chalk unit 5 represents a local geological feature and could be an indicator for a period of increased erosion with formation of coarse grained sediments the archaeological horizons form the lower parts of unit 4 and yielded osl ages between 55 and 65 ka indicating an affiliation to the sediments called ashmura formation with an upper pleistocene age for the site the channel fills of unit 2 can be dated by the recovered artifacts these range in age from the upper paleolithic aurignacian to historic times unit 1 is recent the study of the complex nmo stratigraphy combined with coherent osl chronology has enabled us to reconstruct parts of the geological history of the hula basin during the late pleistocene it is this history that forms the background for the human migration and utilization of natural resources in the upper jordan rift valley

estimation of wave phase speed and nearshore bathymetry from video imagery a new remote sensing technique based on video image processing has been developed for the estimation of nearshore bathymetry the shoreward propagation of waves is measured using pixel intensity time series collected at a cross shore array of locations using remotely operated video cameras the incident band is identified and the cross spectral matrix is calculated for this band the cross shore component of wavenumber is found as the gradient in phase of the first complex empirical orthogonal function of this matrix water depth is then inferred from linear wave theory s dispersion relationship full bathymetry maps may be measured by collecting data in a large array composed of both cross shore and longshore lines data are collected hourly throughout the day and a stable daily estimate of bathymetry is calculated from the median of the hourly estimates the technique was tested using 30 days of hourly data collected at the sandyduck experiment in duck north carolina in october 1997 errors calculated as the difference between estimated depth and ground truth data show a mean bias of 35 cm rms error 91 cm expressed as a fraction of the true water depth the mean percent error was 13 rms error 34 excluding the region of known wave nonlinearities over the bar crest the accuracy of the technique improved and the mean rms error was 20 cm 75 cm additionally under low amplitude swells wave height h 1 m the performance of the technique across the entire profile improved to 6 29 of the true water depth with a mean rms error of 12 cm 71 cm

young faults in the hula pull apart basin central dead sea transform abstract the geometry and nature of structural features inside the hula pull apart basin at the central dead sea transform are presented here two systems of n s left lateral strike slip faults are located on the east and west sides of the hula basin both fault systems are composed of several segments arranged in a right stepping en echelon pattern the northern end of each segment is bent northeastward and usually merges with the next segment elevated regions and small hills appear on the northern side of each bend the strike slip faults are oblique with both vertical and horizontal components the vertical component may be normal or reverse although the hula valley is subjected to general extension the studied structures indicate local compression inside the basin normal faults striking e w comprise the northern border of the hula basin age determination of displaced travertines and basalts along the faults indicates sub recent tectonic activity and suggests migration of normal faulting towards the inner part of the basin the youngest fault displaces travertine dated at 25 300 years

salinization and dilution history of ground water discharging into the sea of galilee the dead sea transform israel abstract the mechanism governing salinization of ground water discharging into the sea of galilee in israel has been the subject of debate for several decades because the lake provides 25 of the water consumed annually in israel correct identification of the salt sources is essential for the establishment of suitable water management strategies for the lake and the ground water in the surrounding aquifers existing salinization models were evaluated in light of available and newly acquired data including general chemistry and o h c and cl isotopes based on the chemical and isotopic observations the proposed salt source is an ancient intensively evaporated brine 21 to 33 fold seawater which percolated through the valley formations from a lake which had formed in the rift valley following seawater intrusion during the late miocene low na cl and high br cl values support the extensive evaporation whereas high ca cl and low mg cl values indicate the impact of dolomitization of the carbonate host rock on the residual solution based on radiocarbon and other isotope data the dilution of the original brine occurred in two stages the first took place 30 000 a ago by slightly evaporated fresh to brackish lake water to form the sea of galilee brine the second dilution phase is associated with the current hydrological regime as the sea of galilee brine migrates upward along the rift faults and mixes with the actively circulating fresh ground water to form the saline springs the spatially variable chemical and isotopic features of the saline springs suggest not only differential dilution by fresh meteoric water but also differential percolation timing of the original brine into the tectonically disconnected blocks registering different evaporation stages in the original brine consequently various operations to reduce the brine contribution to the lake may be differentially effective in the various areas

the structure and morphotectonics of the gesher benot ya aqov area northern dead sea rift israel abstract geological geomorphological and morphotectonic studies at the gesher benot ya aqov acheulean site northern jordan valley provide 1 a unique opportunity to establish the ecological background of hominid behavior during the early stages of widespread human occupation 2 crucial data for understanding the paleo environment and the various processes that affected the area near the gesher benot ya aqov site and 3 a basis for further comprehensive research in the region quaternary tectonic activity near the acheulean archeological site has produced a complex local setting that controls the surrounding landscape tectonic activity formed the benot ya aqov embayment which attracted hominids and a variety of other fauna sediments of the benot ya akov formation deposited in the embayment facilitated excellent preservation of the remnants of acheulean hominid activities and of abundant floral and faunal remains the formation was subsequently affected by faulting and folding local uplift ended the deposition of lacustrine sediments in the embayment of hula valley basin and caused erosion and vertical incision of the jordan river that resulted in the capture of the rosh pinna river and the exposure of the benot ya akov formation these deposits are found in different structural positions along the north south oriented morphotectonic embayment the outcrops contain numerous archeological sites giving the study area an unusually high potential for future hominid discoveries

air humidity and lake δ18o during the latest paleocene earliest eocene in france from recent and fossil fresh water and marine gastropod δ18o δ13c and 87sr 86sr detailed isotopic 18 o 13 c 87 sr 86 sr analyses have been performed on aragonitic fresh water brackish water and marine gastropod shells of latest paleocene earliest eocene age from northwestern europe fresh water shells e g viviparus lymnaea from sparnacian deposits in the paris basin show relatively high 18 o values in the range 4 to 0 1 large intrashell 18 o variability typically 3 is consistent with significant seasonal variation in precipitation and or temperature we also present intrashell isotopic profiles for 22 recent fresh water shells mainly viviparidae representing the major middle to low latitude climate zones e g sweden france portugal lake chad ceylon gambia congo lake victoria new guinea distinct isotopic patterns reflecting humidity and temperature characterize each of the climate zones comparing the results for recent and fossil shells suggests that the climate in northern france during sparnacian time was warm subtropical with a pronounced seasonal drought the 18 o composition of sparnacian lake water has been estimated from the fossil fresh water shell 18 o and by using seasonal temperatures derived from 18 o profiles of fully marine shells the best estimate of the 18 o composition of sparnacian lake water compared with eocene mean ocean water is 1 this is consistent with paleorain 18 o values of 3 to 5 similar to present mean rain 18 o standard mean ocean water values close to 4 in portugal at 40 n the paleolatitude of the paris basin during earliest eocene time the evaporated nature of sparnacian lake water contradicts hypotheses of globally equable humid conditions in the warm early eocene and instead suggests that dry subtropical highs occurred over the eastern parts of the oceans similar to today the results of this study demonstrate the potential of fossil fresh water carbonates to reconstruct the development of subtropical highs and hadley cell circulation in the past

oxygen and carbon isotopic records of mollusks in the kuokang shell bed taiwan implications and applications abstract oxygen and carbon isotopic compositions have been determined in fossil molluscan shells from the kuokang shell bed and in modern shells from coastal areas around taiwan fossil mollusks have been well preserved based on x ray diffraction stable isotopic data and their occurrence in the field the stable isotopic data of fossil shells indicate that they lived in an open sea environment heavier oxygen and lighter carbon isotopic ratios of these fossils relative to modern counterparts around taiwan indicate that these fossil mollusks grew in a glacial period as supported by the 14c dating results the calculated mean uplift rate for the kuokang shell bed shows a lower rate compared to the eastern and southern parts of taiwan and reflects a more stable away from collision nature for western taiwan

a mid pleistocene deformation transition in the hula basin northern israel implications for the tectonic evolution of the dead sea fault the dead sea fault dsf plate boundary has accommodated relative sinistral motion between the sinai and arabian plates since the neogene geologically based models point to a long term 5 0 ma n trending relative motion roughly parallel to the central sector of the dsf gps based calculations of present day relative motion between the sinai and arabian plates indicate a northward increasing convergent component across the dsf suggesting a kinematic change over the plio pleistocene period we study the evolving deformation of the hula rhomb shaped graben situated along the central sector of the dsf in order to examine the possible kinematic change the hula graben is widely accepted as a pull apart basin part of a series of basins extending southward we use a 3 d approach combining mapped surface structures with subsurface seismic reflection profiles 173 km and borehole data 38 boreholes gathered here into a single geographic information systems database results indicate that during the mid pleistocene a major tectonic transition modified the structure of the basin fill a subvertical nnw trending left lateral throughgoing strike slip fault developed diagonally across the basin consequently the basin entered a new geodynamic phase where subsidence was controlled by both the basin bordering faults and the diagonal fault while the vertical displacement across the transverse faults is minor synchronous structural changes recorded in additional localities along the dsf attests to a mid pleistocene 1 ma regional tectonic transition that was associated with a northward increasing convergent component across the central and northern sectors of the dsf

pleistocene paleoclimate of the arid region of israel as recorded in calcite deposits along regional transverse faults and in veins abstract the 18o and 13c values of the calcites associated with e w and ne sw transverse faults in the negev israel indicate that calcite was deposited from meteoric water a regional change in the 18o and 13c values was observed the 18o content in the calcite increases from the southwestern 18 o 17 8 to the northeastern 18 o 2 9 part of the region the 13c values show the opposite trend of the 13c content decrease from 2 in the south to 10 in the northeast these trends had to reflect changes in regional paleoclimate suggesting a change in the isotopic composition of the solution from which the calcite was deposited in different periods the variations in the 18o values reflect shifts in the 18o values of precipitation and are associated with a change in the source of moist air masses which came from the equatorial atlantic in the early pleistocene and from the mediterranean during a later period variations in 13c values reflect changes from humid to arid conditions two modes of calcite deposition are suggested 1 precipitation of calcite minerals in the unsaturated zone following the dissolution in the soil or 2 calcite deposition that occurred as co2 was lost during emergence of paleogroundwater from lower cretaceous and jurassic aquifers

alongshore momentum balances in the nearshore the one dimensional time averaged over many wave periods along shore momentum balance between forcing by wind and breaking waves and the bottom stress is examined with field observations spanning a wide range of con ditions on a barred beach near bottom horizontal currents were measured for 2 months at 15 locations along a cross shore transect extending 750 m from the shoreline to 8 m water depth the hourly averaged bottom stress was estimated from observed currents using a quadratic drag law the wave radiation stress was estimated in 8 m depth from an array of pressure sensors and the wind stress was estimated from an anemometer at the seaward end of a nearby pier the combined wind and wave forcing integrated over the entire cross shore transect is balanced by the integrated bottom stress the wind stress contributes about one third of the forcing over the transect analysis of the momentum balances in different cross shore regions shows that in the surf zone wave forcing is much larger than wind forcing and that the bottom drag coefficient is larger in the surf zone than farther seaward consistent with earlier studies

the use of tritium in groundwater to determine fluid mean residence times of valles caldera hydrothermal fluids new mexico usa abstract naturally and artificially produced 3 h in precipitation is used to place limits on mean residence times of fluids associated with the valles caldera geothermal reservoir the 3 h concentrations in precipitation are used to calculate fluid mean residence times using two end member cases piston flow and well mixed reservoirs these simplified models using 3 h yield relative fluid mean residence times in different portions of the system in situ 3 h production in the reservoir through neutron interaction with 6 li is considered and only very low levels of 3 h 0 01 t u are contributed to the waters by this process calculations using the end member cases at valles caldera indicate that mean residence times of geothermal waters in the reservoir are between 3000 and 10 000 years the results also show that the two distinct subsystems of the main reservoir are associated with different fluid mean residence times waters in the redondo creek subsystem are older 4300 to 10 000 years than waters in the sulphur springs subsystem 2000 4400 years comparison of the results of the end member cases with those obtained using more sophisticated methods indicates that the two end member cases with the use of 3 h can provide acceptable limits order of magnitude on a fluid s mean residence time and volumes within a reservoir

the middle palaeolithic nahal mahanayeem outlet site israel reconstructing the environment of late pleistocene wetlands in the eastern mediterranean from ostracods abstract we present ostracod data from the middle palaeolithic open air site of nahal mahanayeem outlet nmo at the southern edge of the hula basin northern israel sediments of two pleistocene water bodies are exposed at the site the first one is an archaeologically sterile light colored limnic carbonate with an early pleistocene age it contains an ostracod fauna assemblage dominated by candona neglecta candonopsis kingsleii and pseudocandona sp and in minor abundances cypria ophtalmica cyprideis sp humphcypris sp fabaeformiscandona cf fabaeformis and ilyocypris sp these sediments were deposited in a shallow freshwater to oligohaline lake under stable conditions sediments of the second water body are silty and dark colored with a depositional age of 65 ka belonging to the late pleistocene ashmura formation the unit covers a geologically complex topography of tectonically uplifted limnic deposits and a hill like gravel bar at the site the most important archaeological layer is situated at its base containing a lithic assemblage ascribed primarily to the middle palaeolithic mousterian tradition and very well preserved flora and fauna in the sediments from the archaeological layers the brackish water ostracod cyprideis torosa and the foraminifer ammonia tepida could be identified in sediments of the ashmura formation taken near the site c neglecta candona angulata ilyocypris sp c kingsleii pseudocandona sp c ophtalmica darwinula stevensoni trajancypris sp and potamocypris smaragdina were found indicating a freshwater to slightly oligohaline stagnant water body the ostracod fauna of the nmo site together with geochemical data allow us to reconstruct a depositional environment of the margin at a shallow lake with brackish or saline springs nearby during the site s occupation by middle palaeolithic humans additionally candona weltneri candona cf meerfeldiana c kingsleii cyclocypris laevis c ophtalmica cyprideis sp fabaeformiscandona cf fabaeformis p smaragdina pseudocandona depressa trajancypris sp zonocypris cf costata and a tepida could be recorded for the first time for the pleistocene limnic strata of the hula basin

climate variability in the upper jordan valley around 0 78 ma inferences from time series stable isotopes of viviparidae supported by mollusc and plant palaeoecology abstract the early middle pleistocene lacustrine sediments at gesher benot ya aqov gby in the upper jordan valley span ca 100 ka across the matuyama brunhes boundary mbb at 780 ka and oxygen isotope stages oiss 20 to 18 provide a continuous record of their sedimentary history and prevailing climate the lacustrine environment is investigated using ecological and stable isotope characteristics of gastropods belonging to the family viviparidae supplemented by other molluscan and floral indicators the sedimentary framework of the 34 m thick sequence is bounded by channel conglomerates at its base and top and consists of six sedimentary cycles each one starts with shore sediments coquina and sand and ends with deeper water sediments black mud or gray mud time series of 18o and 13c values were determined in individual shells belonging to two sympatric genera of viviparid gastropods viviparus apameae galileae and bellamya sp found in the sedimentary cycles 2 through 5 the total overall range of 18o in the time series of all the shells is from 10 5 to 5 2 vpdb and the 13c from 9 2 to 4 8 vpdb the 13c values of shells recovered from black mud are lower than those from the other sediment types suggesting a higher proportion of carbon of organic origin the 18o values show only a weak relation with sediment type the time series of the individual shells indicate a relative constancy in the water 18o and temperature whilst the variation in 13c could be related to the annual productivity cycle growth and decay of aquatic plants of the lake the 13c patterns in the time series and winter rings indicate that the rate of growth of the individual snails was ca 15 30 mm year the isotopic characteristics of the viviparid shells from these beds indicate diverse sedimentary environments and suggest that above the mbb cycles 2 5 the gby lake received constant and isotopically consistent water inflow our integrated data isotopic and ecological of molluscs and ecological of plants indicates that the geophysical magnetic phenomenon of mbb coincides with an environmental change from a relatively cold dry climate towards a warmer temperate subtropical climate in this region this change coincides with the occurrence of hominin artifacts which were found mainly in layers of the sedimentary cycles 3 5

stable carbon and oxygen isotopic composition of early holocene gastropods from wadi mansurab north central sudan the 8500 to 7000 year old shell bearing sediments in shallow claypans near wadi mansurab in north central sudan appear to reflect a widespread and much wetter period in northeast africa stable carbon and oxygen isotope analysis of the wadi mansurab gastropods reveals that the shell carbonate is highly depleted in 13c and 18o the highly depleted oxygen isotopic composition is indicative of rainfall derived from a distant oceanic source the highly negative nature of the oxygen isotopes indicates that the region had significantly less evaporation than today while the extreme variability in isotopic composition up to 6 7 pdb is consist ent with a seasonal rainfall regime characterized by a high degree of inter annual variability the dominance of semi aquatic and swamp dwelling gastropods over truly aquatic species implies that the region was probably a seasonally flooded grassplain similar to the toich lands of south central sudan today our data support the inference that towards 8500 7000 bp there