will the dead sea die the level of the dead sea the lowest surface on earth is currently declining at a rate of 0 8 m yr and has dropped about 20 m since the beginning of the twentieth century it reached 410 m in 1997 we address the question of whether the level of the dead sea will continue to decline a numerical model developed in this study to determine the water balance accounts for the increase in salinity and the concomitant decrease in the rate of evaporation that accompanies reduction in the activity of the water simulations based on ranges of water withdrawal scenarios suggest that the dead sea will not die rather a new equilibrium is likely to be reached in about 400 yr after a water level decrease of 100 to 150 m

environmental implications of salt facies in the dead sea thick sequences of salt halite have been recovered in a 456 m long core drilled at the deepest floor of the dead sea by the dead sea deep drilling project and extending 200 k y back in time the salt sequences were precipitated in the ancient lake that occupied the dead sea basin during the last three interglacials during intervals of extreme aridity in the lake s watershed the salt layers alternate with mud layers that indicate wetter periods in the watershed when floods transported fine detritus matter to the lake the salt sources include brine discharge and freshwater runoff that dissolved halite units dissolved salts accumulated in the lake during glacials and relatively wet periods when the lake expanded and precipitated during interglacials when the lake levels dropped this study establishes for the first time the evaporite facies and sedimentological features of the deep dead sea brine during interglacial periods by using the modern precipitation of halite in the dead sea as an analogue for past halite depositional periods as recorded in the drill core the halite intervals provide a record of facies characterizing a deep water evaporitic environment the halite layers consist mainly of two types of crystals small cumulate crystals containing halite rafts which indicate precipitation from the surface brine of the lake epilimnion and bottom growth usually large halite crystals that precipitated on the lake floor hypolimnion the layers of small halite crystals formed during drier periods as compared to the bottom growth crystals the bottom growth halite crystals contain variable quantities of detritus and show mild dissolution structures at the contact between the mud and the halite crystals these two main types of halite in combination with muds and gypsum comprise seven categories of salt facies that reflect the hydrological conditions dry to wet and that display a cyclic decadal to millennial pattern along the sampled core intervals frequent alternation of these two salt crystal types suggests seasonal changes whereby the small cumulate crystals were formed during the summer and the bottom growth crystals were formed during the winter when the surface temperatures of the lake were low and the surface water was less saline and less likely to be saturated with respect to halite comparison of the last interglacial halite with the modern halite facies together with the absence of significant dissolution features within the halite and the cyclic nature of the facies indicates that the lake was continuously deep 100 m during the last 200 k y

the seismicity along the dead sea fault during the last 60 000 years abstract evidence for unchanging slip rate and a gutenberg richter relation for earthquake distribution along the dead sea fault during the past 60 000 yr are presented the evidence comes from three different segments approximately 100 km apart and from three different timescales prehistoric paleoseismic historical and modern instrumental records the paleoseismic data are based on two different methods in the southern arava valley and the northern jordan valley segments the amount of normal displacement along several faults is used while in the dead sea basin the appearance of brecciated beds which are considered as seismites is used we found that for the southern arava valley segment a constant dip slip rate of 0 5 mm yr can explain the cumulative normal slip during the past 45 000 yr this suggests that normal faulting is only 10 of the total left lateral strike slip motion we also found that for all three segments the paleoseismic and historical records of strong earthquakes lie on the linear extrapolation of the frequency magnitude relation of the instrumental record the calculated b values for all three segments are between 0 85 and 1 similar to other major strike slip faults in the world it is concluded that the gutenberg richter distribution is a stable mode in the tectonic setting of the dead sea fault during the past 60 000 yr

enhanced saharan dust input to the levant during heinrich stadials abstract the history of dust transport to the levant during the last glacial period is reconstructed using the isotope ratios of pb sr nd and hf in sediments of lake lisan the last glacial dead sea exposed marginal sections of the lisan formation were sampled near masada the perazim valley and from a core drilled at the deep floor of the modern lake bulk samples and size fractions display unique isotopic fingerprints the finest detritus fraction 87 sr 86 sr and lower end values 0 710 0 713 and 7 0 to 9 8 respectively relative to the coarser fractions 5 20 m and 206 pb 204 pb 207 pb 204 pb and 208 pb 204 pb ratios 18 26 19 02 15 634 15 68 and 38 25 38 82 respectively are systematically higher in the finest detritus fraction relative to corresponding coarser fractions and bulk samples the 87 sr 86 sr and end values of the finest fraction correspond with those of atmospheric dust originating from the sahara desert while those of the coarse fractions are similar to loess deposits exposed in the sinai and negev deserts pronounced excursions in the sr nd pb isotope ratios toward more sahara like values coincide with the heinrich h stadials 6 5 and 1 reflecting significant increases in saharan dust fluxes during regionally arid intervals reflected by sharp lake level drops moreover during h6 the dust came from different saharan sources than during h1 and h5 while the relatively wet glacial climate in the levant suppressed the transport of dust to the lake watershed short term hyper arid spells during h stadial intervals were accompanied by enhanced supply of fine sahara dust to this region

climatic versus tectonic controls of fan sequences lessons from the dead sea israel tectonic activity is commonly held responsible for abrupt coarsening of alluvial fan sequences and the role of climate is often relegated the pleistocene fans of the dead sea rift indicate clearly the problems of differentiating the sedimentary signatures of climatic and tectonic adjustments in a closed lake basin exposures are excellent the rivers are currently incising in response to the low lake levels of the holocene producing cliffs 50m high these reveal an interdigitation of lake deposits dominantly fine grained carbonates and the coarse river gravels which characterize the fan deposits the bounds of each facies are sharp river sediments are superimposed on lake sediments with little evidence of either reworking or loading in turn aragonite crusts are draped over alluvial gravels indicating the sudden return of still water conditions neither can be explained by gradual adjustment of the hinterland river system after tectonic shock instead it is clear that the coarse alluvium was deposited by discrete high magnitude floods that occurred only sporadically because of the infrequent nature of rainfall in this arid environment in interpreting basin development in ancient settings it is always tempting to assume that coarse deposits are indicative of tectonism however the dead sea fans demonstrate that climate is just as likely to be responsible for the conglomerates in a sedimentary sequence

late neogene rift valley fill sediments preserved in caves of the dead sea fault escarpment israel palaeogeographic and morphotectonic implications evaporitic lagoonal marl and dolomite laminar fill sediments are preserved in relict dry caves of the dead sea fault escarpment israel which has been tectonically active since the late neogene the hosting caves are located within turonian massive carbonate bedrock and at higher altitudes than previously documented fill sediments of the dead sea depression based on the relative altitudes of the cave sediments the reversed stratigraphy of the dead sea depression fill sediments possible partial correlation of the cave sediments with other fill sedimentary units of the depression and sedimentary geochemical and mineralogical characteristics it is concluded that i the cave sediments are among the oldest of the depression fill and ii the deposition of the cave sediments took place in hypersaline dolomite precipitating water bodies of late neogene age during the initial morphotectonic stages of the depression formation variable and relatively low sr ca and 34s ratios of the cave sediments assuming precipitation from sea water suggest variable fresh water input into the depositional brine the present altitudes of the cave sediments reflect late neogene levels of water bodies in the depression modified by vertical post late neogene tectonic movements within the still active fault escarpment according to these altitudes a 50 to 250 m uplift of the western margins of the depression since the late miocene to early pliocene is inferred

formation of the upper pleistocene terraces of lake van turkey sedimentological and geomorphological studies of terraces around lake van 1647 m provided a preliminary framework for lake level variations the elevations of terraces and past lake level were measured with a differential global positioning system a chronology is developed using 234 u 230 th dating of travertines 39 ar 40 ar dating of pyroclastites and 14 c dating of organic matter facies and stratigraphic correlations identify four transgressions c1 0 c 1 00 c 2 0 and c2 00 each followed by a regression which ended with low lake levels that caused river incision and terrace formation evidence of the oldest transgression c1 0 is found in the uppermost reaches of valleys up to 1755 m an altitude higher than the present lake threshold 1736 m this c1 0 transgression may be related to pyroclastic flows which dammed an outlet located in the western part of the lake basin and which is dated to before 105 ka after 100 ka a second transgression c1 00 reached 1730 1735 m possibly related to a younger ignimbrite flow in association with high water inflow warm and or wetter conditions the two younger transgressions reached 1700 1705 m the first one c2 0 is dated to 26 24 5 cal ka bp and the second one c2 00 to 21 20 cal ka bp available data suggest that the long term lake level changes responded mainly to climate oscillations additional events such as river captures caused by volcanic falls filling valleys tectonism erosion and karstic diversion may have impacted these long term lake level changes copyright 2010 john wiley sons ltd

analytical solutions to non fickian subsurface dispersion in uniform groundwater flow abstract analytical solutions are obtained by the fourier transform technique for the one two and three dimensional transport of a conservative solute injected instantaneously in a uniform groundwater flow these solutions account for dispersive non linearity caused by the heterogeneity of the hydraulic properties of aquifer systems and can be used as building blocks to construct solutions by convolution principle of superposition for source conditions other than slug injection the dispersivity is assumed to vary parabolically with time and is thus constant for the entire system at any given time two approaches for estimating time dependent dispersion parameters are developed for two dimensional plumes they both require minimal field tracer test data and therefore represent useful tools for assessing real world aquifer contamination sites the first approach requires mapped plume area measurements at two specific times after the tracer injection the second approach requires concentration versus time data from two sampling wells through which the plume passes detailed examples and comparisons with other procedures show that the methods presented herein are sufficiently accurate and easier to use than other available methods

shoreline processes and the age of the lake lahontan highstand in the jessup embayment nevada the well developed shoreline record of pluvial lake lahontan in the jessup embayment nevada is used to refine the history of late pleistocene lake level fluctuations and to assess controls on shoreline development and distribution controls on the strength and type of shorelines developed include local slope the amount and characteristics of sediment available for transport the availability of accommodation space and length of time the lake level resides at a particular shoreline elevation at the sehoo highstand and during the early part of the regression strong storm winds and waves from the south southeast set up a clockwise net shore drift pattern near the head of the embayment although significant differences in local slope geometry of the shoreline and wave energy existed in the embayment crestal heights of constructional shoreline features formed at the highstand vary 2 6 m in elevation and hence provide a relatively precise marker of the highstand elevation radiocarbon dating of a camel bone preserved in high shoreline deposits indicates that the lake reached its highest elevation of 1338 5 m in the embayment and receded from that elevation immediately prior to 13 070 60 yr b p similar and slightly older radiocarbon ages on gastropod shells preserved in barrier deposits at 1327 m 13 280 110 yr b p and 1331 m 13 110 110 yr b p suggest that the final rise to the highstand was very rapid and that the lake maintained its highest stand for a very brief period of time perhaps only for years or decades the brevity of the highstand is reasonable in light of the recent formation of similar barrier features in modern pyramid lake which formed in less than seven months due to a rapid increase in lake level

synoptic conditions of fine particle transport to the last interglacial red sea dead sea from nd sr compositions of sediment cores abstract the sediments deposited at the depocenter of the dead sea comprise high resolution archive of hydrological changes in the lake s watershed and record the desert dust transport to the region this paper reconstructs the dust transport to the region during the termination of glacial marine isotope stage 6 mis 6 135 129 ka and the last interglacial peak period mis5e 129 116 ka we use chemical and nd and sr isotope compositions of fine detritus material recovered from sediment core drilled at the deepest floor of the dead sea the data is integrated with data achieved from cores drilled at the floor of the red sea thus forming a red sea dead sea transect extending from the desert belt to the mediterranean climate zone the dead sea accumulated flood sediments derived from three regional surface cover types settled desert dust mountain loess soils and loess soils filling valleys in the dead sea watershed termed here valley loess the valley loess shows a distinct 87sr 86sr ratio of 0 7081 1 inherited from dissolved detrital calcites that originate from dried waterbodies in the sahara and are transported with the dust to the entire transect our hydro climate and synoptic conditions reconstruction illustrates the following history during glacial period mis6 mediterranean cyclones governed the transport of saharan dust and rains to the dead sea watershed driving the development of both mountain soils and valley loess then at heinrich event 11 dry western winds blew saharan dust over the entire red sea dead sea transect marking latitudinal expansion of the desert belt later when global sea level rose the dead sea watershed went through extreme aridity the lake retreated depositing salt and accumulating fine detritus of the valley loess during peak interglacial mis 5e enhanced flooding activity flushed the mountain soils and fine detritus from all around the dead sea and red sea marking a significant contraction of the desert belt at the end of mis 5e the effect of the regional precipitation diminished and the dead sea and red sea areas re entered sever arid conditions with extensive salt deposition at the dead sea

geomorphological contributions to palaeolimnology on the african continent abstract article history received 19 december 2007received in revised form 5 july 2008accepted 22 july 2008available online 3 august 2008keywords quaternarybeach ridgeshorelinelakemultiproxyosl lakes are highly informative repositories of information of the terrestrial response to regional and global climatedrivers in quaternary studies lake oor records are now frequently used to establish the magnitude timing andgeographicalextentofhumid aridtransitionsovertimescalesof10 2 10 4 years whiletheresolutionof thisrecordisunparalleled much of the geochemical and sedimentary da ta is challenging to interpret and highly basin speci c geomorphologicalproxies particularlyshorelines offeranadditionaloralternativerecordoflakehistory withrecenttechnological advances facilitating both access to and the utility of this proxy record recent advances in opticallystimulated luminescence osl dating allow the determination of the age of beach ridge emplacement in theabsence of organic material while the availabilityof shuttle radar topography mission srtm data in conjunctionwith digital elevation models dem aids in the identi cation of shoreline features and the topographicreconstruction of the former extent of palaeolakes here we highlight and illustrate the use of lacustrine shorelinefeatures for unravelling a quaternary climate signal wit hin africa from otherwise inaccessible and undatablepalaeolake records in the semi arid and arid subtropics an d identify their contribution towards high resolutionmultiproxy reconstructions of tropical low latitude quaternary environments and climates 2008 elsevier b v all rights reserved

hypersaline brine diagenesis and evolution in the dead sea lake lisan system israel abstract water soluble salts were extracted from 57 aragonite and detrital laminae sampled from the pleistocene lake lisan sediments the solutions and solids were analysed for ca mg na k sr cl so 4 and bicarbonate average na cl mg ca sr ca mg cl ca cl sr cl k cl k na and k mg ratios calculated for seven stratigraphie elevations in the lisan column indicate that the dead sea rift sediment brine system has remained practically closed for 70000 years the soluble salts reflect both the hydrologie evolution of the lake as well as diagenetic processes mg ca ratios systematically decrease in younger sediments and this decline is accompanied by a 1 5 4 fold sr enrichment in aragonite solubles relative to salts extracted from detrital laminae the major process responsible for these observations is dolomitization of sr rich aragonite by interstitial brine diagenesis was triggered by slow desiccation of the lake s sediments after the lisan waters started to recede due to a change in climate very sharp chemical gradients which developed in the sediments after deposition have been preserved because further diagenesis was quenched by the advancing dry out h 2 o loss by evaporation induced difrusional migration of na and cl from aragonite laminae into adjacent detrital layers this lowered the na cl ratio in the aragonite and raised it in the detritus relative to the initial dead sea na cl ratio of 0 26 the early lisan brine was similar in its chemical composition and total salinity to that of the present dead sea

high resolution geological record of historic earthquakes in the dead sea basin a 2000 year paleoseismic record of the dead sea area was recovered from a lacustrine sedimentary section the section is being exposed at the ze elim terrace on the shores of the dead sea due to the fast retreat of the lake the section consists of laminated detrital and chemical mainly aragonite sediments that were deposited in the holocene paleo dead sea eight layers in the section show deformed sedimentary structures and are identified as seismites their chronology was determined by radiocarbon dating on organic remains the seismite ages are well correlated with the historically documented earthquakes of 64 and 31 b c and 33 363 1212 1293 1834 and 1927 a d the few historically documented earthquakes that have no correlatives in the ze elim seismite record occurred in times of sedimentary hiatuses at this site e g 749 a d based on modern analogues and the association of similar disturbed layers with syndepositional faults the ze elim terrace seismites indicate m 5 5 earthquakes the average recurrence interval is estimated as 100 300 years and represents slip events on different faults in the dead sea area the ze elim section provides a unique opportunity to correlate two independent and extensive data sets the historical and sedimentary records this study opens the way for better understanding of spatial and temporal distribution of earthquakes along the dead sea transform and elsewhere

thin bed avo compensating for the effects of nmo on reflectivity sequences estimating the amplitude versus offset avo gradient for thin beds is problematic because of offset dependent tuning and nmo stretch when avo analysis is carried out before nmo correction the nonparallel nature of the nmo hyperbolas results in differential interference conditions at each offset and complicates avo interpretation if avo analysis is carried out after nmo correction the data bandwidth is distorted and corrections must be made to recover the true avo response a correction for nmo stretch can be applied to fourier spectra obtained after windowing the nmo corrected prestack data this approach requires knowledge of the seismic wavelet but seems to be relatively insensitive to noise in the data or uncertainties in the wavelet estimation the technique allows the interference conditions to be made independent of offset and the correct avo gradient relative to the normal incidence amplitude to be recovered

high resolution record of geomagnetic secular variation from late pleistocene lake lisan sediments paleo dead sea we measured geomagnetic secular variation in lake lisan sediments paleo dead sea more than 1500 oriented samples were collected from a 27 3 m section of alternating aragonite and detritus laminae in the dead sea basin ranging in age from 67 to 32 ka the natural remanent magnetization nrm is carried by titanomagnetite in the detrital laminae whereas the aragonite is diamagnetic the nrm is very stable and was acquired several hundred years after deposition the mean direction of 878 horizons is dd 005o id 45o 95d 1o d 22 we observed three modes of directional geomagnetic variation as a function of and by inference time very rapid inter sample changes slow variation in mean direction and inclination shallowing of about 1o m the overall rate of change in direction is 0 57 0 57o year not significantly different from zero for about 83 of the record the rate of change is less than 1o year and comparable to historical values high rates of change are observed more frequently in the lisan than in historical records and peak rates are up to ten times faster a smoothed curve resulting in a maximum rate of change of 0 66o year and a mean 0 10 0 10o year may be a more realistic representation of the field behavior no reverse nrms were observed but geomagnetic field excursions may be present where the vgps deviate by more than 40o from the geographic north at about 52 and 41 ka the latter may represent the laschamp event 1998 elsevier science b v all rights reserved

a new dead sea pollen record reveals the last glacial paleoenvironment of the southern levant abstract the southern levant is a key region for studying vegetation developments in relation to climate dynamics and hominin migration processes in the past due to the sensitivity of the vegetation to climate variations and the long history of different anthropogenic occupation phases however paleoenvironmental conditions in the southern levant during the late pleistocene were still insufficiently understood therefore we investigated the vegetation and fire history of the dead sea region during the last glacial period we present a new palynological study conducted on sediments of lake lisan the last glacial precursor of the dead sea the sediments were recovered from the center of the modern dead sea within an icdp campaign the palynological results suggest that irano turanian steppe and saharo arabian desert vegetation prevailed in the dead sea region during the investigated period ca 88 000 14 000 years bp nevertheless mediterranean woodland elements significantly contributed to the vegetation composition suggesting moderate amounts of available water for plants the early last glacial was characterized by dynamic climate conditions with pronounced dry phases and high but unstable fire activity anatomically modern humans entered the southern levant during a climatically stable phase late mis 4 mis 3 with diverse habitats constant moisture availability and low fire activity mis 2 was the coldest phase of the investigated timeframe causing changes in woodland composition and a widespread occurrence of steppe we used a biome modeling approach to assess regional vegetation patterns under changing climate conditions and to evaluate different climate scenarios for the last glacial levant the study provides new insights into the environmental responses of the dead sea region to climate variations through time it contributes towards our understanding of the paleoenvironmental conditions in the southern levant which functioned as an important corridor for human migration processes

mobilization of fine detritus to the dead sea basin during the late glacial and early holocene abstract the mineralogical grain size and geochemical properties e g nd and sr isotopes mg al ratios of fine detritus that accumulated in the dead sea during the late glacial to early holocene time 22 7 ka are used to identify its sources and modes of transport and to reconstruct the hydroclimate conditions in the dead sea watershed samples were retrieved from the dsddp 5017 1a core that was drilled in the deep floor of the lake and from various exposures of surface cover in the lake s watershed the data show that during most of the late glacial detrital particles were either directly blown mostly from the north sahara desert or were washed from the surface cover loessial soils of the north negev desert and judea desert this picture changed during the end of the last glacial to the early holocene 14 7 ka when the fine detritus showed evidence for contribution from surface cover that contained basaltic soils the contribution of basaltic soils to the fine detritus inventory of the dead sea and to terraces in the jordan valley indicates a period of intense erosion in the northern highlands of the dead sea watershed at an interval that partly coincides with sapropel s1 in contrast during the last interglacial sapropel s5 fine detritus was mostly mobilized to the lake from southern and eastern region of the watershed the formation and accumulation of terraces from this basaltic derived material could be an important factor in the establishment of early agriculture settlements in the jordan valley

stromatolites in caves of the dead sea fault escarpment implications to latest pleistocene lake levels and tectonic subsidence abstract a varied assemblage of algal stromatolites was encountered in caves along the northern section of the dead sea fault escarpment the caves are situated at the lower part of the escarpment at altitudes 310 to 188 m relative to mean sea level m s l i e ca 110 230 m above the present dead sea level the cave stromatolites are mainly composed of aragonite yielding u th ages of 75 17 ka the altitude mineralogy and ages as well as comparison with previously documented stromatolite outcrops in the area ascribe the cave stromatolites to the aragonite precipitating hypersaline lake lisan the late pleistocene predecessor of the dead sea the stromatolites are used as a lake level gauge based on the algae being reliant upon the light of the upper water layer preservation of the original structure and aragonite mineralogy of the stromatolites suggests a closed system regarding the radioactive elements enabling reliable u th dating a curve of lake lisan levels is constructed based on the stromatolite ages and cave elevations the following points are noted 1 lake levels of 247 m relative to m s l are recorded at 75 72 5 ka 2 relatively high lake levels above 220 m relative to m s l are achieved at 41 5 ka and are still recorded at 17 ka 3 the peak level is 188 m relative to m s l at 35 5 29 5 ka these results indicate lake stands up to 80 m higher than previously accepted for large parts of the lake lisan time span this difference is explained by tectonic subsidence of up to 2 2 m ka within the dead sea depression since the latest pleistocene this subsidence rate is in the same order of magnitude with previously calculated subsidence rates for the dead sea depression begin z b zilberman e 1997 main stages and rate of the relief development in israel geological survey of israel report jerusalem unlike previous lake lisan level estimations the new curve is measured at the relatively stable shoulders of the dead sea depression

lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins an example from the early cretaceous jiuquan basin northwestern china development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins however these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development this paper documents fan delta deposition alongside an intrabasinal structural high within the early cretaceous xiagou formation of the jiuquan basin china using subsurface geological and geophysical data deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts suggesting that deposition alongside the structural high is sensitive to lake level changes the temporal and spatial distribution of the fan deltas display retrogradational stacking patterns where fan deltas exhibit a decreasing lateral extent up sequence until fan delta deposition terminated and was replaced by deposition of fine grained lacustrine deposits the retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the xiagou formation subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation likely resulting from border fault movements these data suggest that non uniform stacking patterns in the lower parts of the xiagou formation reflect basin scale tectonic movements as the dominant control on synrift deposition patterns however later stages of xiagou formation deposition were characterized by uniform subsidence across the basin and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault these observations suggest that basin scale tectonic movements played a relatively limited role in controlling sediment deposition and imply a potential change to regional scale processes affecting fan delta deposition during later synrift stages climate change is favored here as the region scale control on the uniform retrogradational fan delta stacking patterns this assertion is supported by pollen assemblages isotope signatures and organic geochemical analyses which collectively suggest a change from a humid to semi arid environment during later synrift stages we suggest that variations in stacking patterns between different fan delta systems can provide insights into the basin and regional scale processes that control rift basin deposition

holocene earthquakes inferred from a fan delta sequence in the dead sea graben abstract the holocene sequence of the fan delta of nahal darga in israel records deformation associated with earthquakes related to the dead sea transform in general and to the jericho fault in particular the fan delta sequence is well exposed and 20 radiocarbon ages help to date the earthquakes that are inferred from a displacement along faults b liquefaction features associated with 11 separate sandy and silty layers and c slumped allocthonous bodies of sediments located directly above one of the main splays of the jericho fault on average an earthquake larger than m 5 5 has occurred approximately every 600 years this estimate is based on the earthquake record of the complete stratigraphic sequence with erosional hiatuses omitted from the calculations the most recently deformed layer is related to the 1927 jericho m l 6 2 earthquake this layer provides a modern analog for the style of soft sediment deformation associated with earthquakes in the late pleistocene and holocene silty sand beds of the fan delta complexes of the dead sea and its predecessor lake lisan

climate cycles in the southern levant and their global climatic connections abstract the history of levant paleo hydrology which is expressed by the absolute water level record of the dead sea over the last 70 kyrs has been shown to be closely coupled with global climate patterns and specifically argued to be modulated by northern hemisphere climate systems here this coupling is rigorously tested and the absolute lake level curve is compared with a variety of globally distributed climate archives and used to deconvolve the processes controlling regional climate and hydrology considering that different archives are based on different sampling resolutions and hence might have inherently different recording sensitivities each of the chosen archives was interpolated and then smoothed at varying temporal resolutions the synthetic curves ranging between temporal smoothing resolutions between 10 years and 15 kyrs were compared to the similarly processed lake level record over the last 60 kyrs the best fit to the dead sea lake level was found to be with antarctica temperatures and atmospheric co2 levels greenland temperatures and proximal archives such as the soreq cave and the dead sea lithological record all yielded weaker correlations to the lake level curve an exception to the strong correlation between levant climate and atmospheric co2 concentrations is observed during marine isotope stage mis 5e at a time when the dead sea watershed was exposed to very weak mediterranean westerly systems that imposed hyperarid conditions and a superposition of southern derived systems that delivered short but intense precipitation to the region at this time antarctic temperatures cross a temperature threshold beyond 1 c above present it is suggested that this exceptional warming phase induces a reorganization of global and regional climate systems influencing the levant these results have two important implications the first is the understanding that global temperatures and atmospheric co2 concentrations impose the first order control over levant climate the second is that the antarctic records can be used as synthetic lake level proxies extending the absolute lake level curve to ca 800 ka compared with its current span of 70 kyrs considering the importance of the dead sea lake level curve as a regional paleo climatic hydrologic recorder the new synthetic curve provides a prominent proxy of levant hydro climate history

sequence stratigraphy of lacustrine deposits a quaternary example from the bonneville basin utah the late quaternary lacustrine sedimentary record in the bonneville lake basin in the eastern great basin provides an excellent example of sequence stratigraphy two sequences referred to as the little valley and bonneville alloformations are exposed in the bluffs of the sevier river where it has entrenched its pleistocene delta between leamington and delta utah both alloformations contain offshore marl units and fine grained deltaic or underflow fan deposits they can be identified and mapped by tracing the unconformity separating them and employing a number of geochronometric tools including amino acid epimerization in fossil gastropods radiocarbon and thorium 230 ages and basaltic tephrochronology thin transgressive sand of the little valley alloformation is overlain by deeper water marl and down lapping regressive phase deltaic silt the bonneville alloformation lies unconformably above the little valley deposits fine grained deltaic sediments deposited during the transgressive phase of lake bonneville fill the entrenched sevier river valley that was eroded subsequent to the little valley lake cycle marl deposited during the deep water phase is overlain by down lapping deposits of the regressive phase below the provo shoreline but is the uppermost unit in the altitudinal range where the lake was lowered catastrophically during the bonneville flood the sequence stratigraphic interpretation leads to the conclusion that the sevier river delta as a whole is probably made up of a number of sediment sequences each composed of several facies recognition of this complexity could be important in potential applications of the stratigraphic model

strontium isotopic chemical and sedimentological evidence for the evolution of lake lisan and the dead sea precise strontium isotope ratios combined with chemical analyses and sedimentological information are used to monitor the water sources and the evolution of the dead sea and its late pleistocene precursor lake lisan 70 18 kyr b p the materials analyzed include bulk aragonite water leached soluble salts and residual aragonite and gypsum from the lisan formation in the perazim valley near the sw shore of the dead sea the residual aragonite and the associated soluble salts display systematic fluctuations in 17sr86sr ratios between 0 70803 and 0 70806 and from 0 70805 to 0 70807 respectively in individual soluble salt residual aragonite pairs the soluble salt displays a higher 87sr86sr ratio gypsum samples yield 17sr86sr ratios similar to the soluble salts from adjacent layers in the section this shows that in individual samples the source of sr in aragonite was distinct from that in soluble salts and the gypsum the sterility of the lisan sediments their strictly nonbioturbated fine lamination and their high content of chloride salts indicate that lake lisan was a saline or even hypersaline water body in the absence of alternative sources of hco3 and s042 the abundance of primary aragonite and gypsum in the lisan column reflects an import of very large volumes of freshwater into the otherwise saline lake resulting in a density stratification of this water body the history of the upper water layer and that of the lower brine is reflected in the chemical and strontium isotope composition of the aragonite and in that of the associated soluble salts and in the gypsum samples respectively whereas the bicarbonate and much of the ca2 required for aragonite crystallization were supplied by the freshwater the complementary ca2 and sr 2 were added by the lower brine the upper water layer of lake lisan acted as a so42 capacitor during the lake s rise periods it was removed therefrom as prominent gypsum beds upon climatic induced drier period mixing or even complete overturn of the lake the evolution of lake lisan took place between two distinct modes the first was characterized by an extensive supply of freshwater and resulted in a rise of the lake s level a density layered structure and precipitation of aragonite the second mode was marked by a diminishing freshwater input resulting in mixing or complete overturn of its water and precipitation of gypsum these two modes reflect the climatic evolution of the region in the late pleistocene which fluctuated between drier and wetter periods the transition to the holocene is accompanied by the dry up of lake lisan and its contraction to the present dead sea

calibration of the 14c time scale to 40 ka by 234u 230th dating of lake lisan sediments last glacial dead sea a new comparison of 14c dates with 234u 230th ages is presented of aragonites from lake lisan the last glacial dead sea between 20 52 cal ka bp the lisan data are coincident with the coral based 14c calendar age calibration through the continuous portion of the curve to 23 5 cal ka bp and with the additional checkpoints at 30 and 40 cal ka bp the agreement with the corals provides evidence for the accuracy of the u th and 14c ages and indicates that lisan aragonites can potentially be used to generate a nearly continuous record of the atmospheric 14c variations through this crucial time interval the lisan data are compared with other records older than 25 cal ka bp from lake suigetsu japan north atlantic foraminifera south african cave deposits and tufa from spain over some age intervals the records show broad agreement over other intervals they diverge all agree that 14c ages were 2 5 0 5 ka younger than calendar ages between 20 32 cal ka bp for ages 32 cal ka bp the lake suigetsu data indicate small differences between 14c ages and calendar ages of less than 1 5 ka the other records broadly agree that 14c ages are too young by 3 1 ka from 32 39 cal ka bp at 40 cal ka bp the foraminifera show equal 14c and calendar ages while the corals lisan aragonites and the spanish tufa indicate a large age difference of 4 5 ka a recent paleomagnetic study of the lisan formation indicates that the high calendar 14c age difference at 40 cal ka bp may be associated with the laschamp paleomagnetic excursion

long term earthquake clustering summary we analyse statistically the long term properties of several instrumental earthquake catalogues complete catalogues exhibit both short and long term clustering for earthquakes of all depth ranges after accounting for the effect of short term clustering we find that in residual declustered catalogues long term clustering not periodicity characterizes the occurrence of all earthquakes shallow intermediate and deep the degree of clustering in residual catalogues is the same for earthquakes in different depth ranges circumstantial evidence indicates that the long term v ariation of seismicity is governed by a power law temporal distribution as in short term clustering it is scale invariant the fractal dimension of an earthquake set on the time axis is of the order of 0 8 0 9 therefore mainshock occurrence is closer to a stationary poisson process than standard aftershock sequences of shallow earthquakes

sea level related architectural trends in coarse grained delta complexes distinct stratigraphical styles of delta development can be related to basically different patterns of relative sea level base level change 1 an overall rise with periods of standstill and without significant fall rs 2 an overall rise with superimposed falls rf 3 an overall fall with superimposed rises fr and 4 an overall fall with periods of standstill and no significant rises fs the related stratigraphical models contain either preserved elements of prototype deltas or show characteristic trends in development from one prototype delta into another each stratigraphical model is characterized by lateral and vertical lithofacies features which can be reasonably well established from outcrop in coarse clastic basin margins where age control is poor sedimentological and stratigraphical delta models as presented here may help refining reconstructions of basin fill patterns and basin subsidence kinematics

primary carbonates and ca chloride brines as monitors of a paleo hydrological regime in the dead sea basin abstract lakes samra lisan and the dead sea occupied the dead sea basin during the last interglacial 140 75 ka bp last glacial 70 14 ka bp and holocene periods respectively the age of lake lisan and samra was determined by u th dating of primary aragonites comprising parts of the lacustrine sedimentary sequences the lakes have periodically deposited sequences of layered calcitic marls lake samra or laminated primary aragonite lake lisan the deposition of aragonite as the primary carbonate phase reflects the contribution of the incoming freshwater loaded with bi carbonate and high mg ca chloride brine that originated from the subsurface vicinity of the dead sea basin deposition of calcitic marls suggests a minor effect of the brines the ca chloride subsurface brine has been migrating in and out of the wall rocks of the dead sea basin reflecting the regional hydrological conditions during most of the last glacial period and during the late holocene sufficient precipitation above the judea mountains pushed the subsurface ca chloride brines into the lakes causing the deposition of aragonite during the last interglacial period the rain that precipitated above the judea mountains was insufficient to induce brine flow toward lake samra it appears that sporadic floods provided calcium bicarbonate and detritus to produce the samra calcitic marls travertines deposited at the samra lisan boundary indicate the early stage in the resumption of groundwater springs activity that led to the resurgence of ca chloride brine and rise of lake lisan similar variations in the regional rain precipitation and hydrological activity probably characterized the long term geochemical evolution of pleistocene lacustrine water bodies in the dead sea basin enabling the use of the carbonates as paleo hydrological monitors

lake levels and sequence stratigraphy of lake lisan the late pleistocene precursor of the dead sea lake lisan the late pleistocene precursor of the dead sea existed from 70 000 to 15 000 yr b p it evolved through frequent water level fluctuations which reflected the regional hydrological and climatic conditions we determined the water level of the lake for the time interval 55 000 15 000 cal yr b p by mapping offshore nearshore and fan delta sediments by application of sequence stratigraphy methods and by dating with radiocarbon and u series methods during the studied time interval the lake level fluctuated between 340 and 160 m below mean sea level msl between 55 000 and 30 000 cal yr b p the lake evolved through short term fluctuations around 280 290 m below msl punctuated at 48 000 43 000 cal yr b p by a drop event to at least 340 m below msl at 27 000 cal yr b p the lake began to rise sharply reaching its maximum elevation of about 164 m below msl between 26 000 and 23 000 cal yr b p then it began dropping and reached 300 m below msl at 15 000 cal yr b p during the holocene the lake corresponding to the present dead sea stabilized at ca 400 m below msl with minor fluctuations the hypsometric curve of the basin indicates that large changes in lake area are expected at above 403 and 385 m below msl at these elevations the lake level is buffered lake lisan was always higher than 380 m below msl indicating a significantly large water contribution to the basin the long and repetitious periods of stabilization at 280 290 m below msl during lake lisan time indicate hydrological control combined with the existence of a physical sill at this elevation crossing this sill could not have been achieved without a dramatic increase in the total water input to the lake as occurred during the fast and intense lake rise from 280 to 160 m below msl at 27 000 cal yr b p

a 40 000 year unchanging seismic regime in the dead sea rift we studied breccia beds in lacustrine sediments within the active dead sea basin the beds were deformed by m 5 5 earthquakes during the past 60 k y our new analysis considers both the thickness of breccia beds and the lithology of beds directly overlying them in order to identify 11 m 7 earthquakes that originated within the dead sea pull apart between 54 and 16 ka the resulting time series is a unique long record of earthquakes in a well constrained segment of a fault system in which the time interval between consecutive earthquakes increased from hundreds of years to a background recurrence interval of 11 k y since ca 40 ka since this recurrence interval is similar to the m 7 2 recurrence interval in the dead sea basin as extrapolated from present seismicity we suggest that the present seismic regime in the dead sea basin as reflected in its magnitude frequency relation as well as in its deficiency in seismic moment has been stationary for the past 40 k y since the increasing interval between consecutive earthquakes in the studied segment of the dead sea fault is time logarithmic it may be a result of healing of the brittle crust as well as a diminishing strain rate following the first strong earthquake in the sequence

10be in lake lisan sediments a proxy for production or climate abstract the geochemical behavior of 10 be in the modern dead sea hydrological limnological system was studied in order to evaluate the feasibility of using dead sea and lake lisan the late pleistocene precursor of the dead sea sediments as archives of the variations in the 10 be production rate 10 be concentrations in detrital and aragonite material from lake lisan laminated sediments were compared to those measured in modern dust terra rossa soil aeolian in origin loess from the negev desert flood suspended load and waters along a rain flood development pathway the transition from rain to incipient runoff and fully developed floods 10 be concentrations decreased throughout the flood development profile from 8 2 10 3 atoms g 1 in the runoff down to 1 10 3 atoms g 1 in dead sea brine due to fast removal of 10 be by the soil and dust particles thus most of the 10 be in the lake is contained within the detrital sediments that collect the 10 be transported by particles from the surrounding terrain e g desert dust with 1 6 0 8 10 8 atoms g 1 and terra rossa soil material with up to 12 5 0 5 10 8 atoms g 1 the high stand periods of lake lisan were characterized by annual deposition of silty detritus sediments reflecting rapid transfer of desert dust to the lake by floods indeed the bulk sediments of lake lisan in which 10 be is associated mainly with silty detritus display 10 be concentrations similar to those of desert dust this demonstrates that 10 be variations were modulated by climate i e particle transport significant positive 10 be peaks up to 1 6 10 8 atoms g 1 appear during intervals of geomagnetic anomalies in lake lisan stratigraphy and in the global record i e during the laschamp geomagnetic event at 41 ka bp this indicates that 10 be atmospheric production signal is superimposed on the climatic 10 be variations we conclude that after de trending of the climatic signal lake lisan sediments may be used as an archive for atmospheric 10 be production

long term earthquake clustering a 50 000 year paleoseismic record in the dead sea graben the temporal distribution of earthquakes in the dead sea graben is studied through a 50 000 year paleoseismic record recovered in laminated sediments of the late pleistocene lake lisan paleo dead sea the lisan represents more than 10 times the 4000 years of historical earthquake records it is the longest and most complete paleoseismic record along the dead sea transform and possibly the longest continuous record on earth it includes unique exposures of seismite beds earthquake induced structures associated with slip events on syndepositional faults the seismites are layers consisting of mixtures of fragmented and pulverized laminae the places where the seismites abut syndepositional faults are interpreted as evidence for their formation at the sediment water interface during slip events on these faults thicker sediment accumulation above the seismites in the downthrown blocks indicates that a seismite formed at the water sediment interface on both sides of the fault scarps modern analogs and the association with surface ruptures suggest that each seismite formed during a m l 5 5 earthquake the 230 th 234 u ages of a columnar section obtained by thermal ionization mass spectrometry give a mean recurrence time of 1600 years of m l 5 5 earthquakes in the dead sea graben the earthquakes cluster in 10 000 year periods separated by quiet periods of similar length this distribution implies that a long term behavior of the dead sea transform should be represented by a mean recurrence of at least 20 000 year record this observation has ramifications for seismic hazard assessment based on shorter records

geochemistry of the lisan and damya formations in jordan and implications for palaeoclimate abstract geochemical mineralogical and sedimentological investigations carried out on the lacustrine lisan and damya formations of the jordan rift valley reveal three major and several minor transgressive depositional cycles all terminating with massive gypsum precipitation the highest level of lake lisan is reported in the literature at 130 m below mean sea level b s l from 70 45 calibrated ka bp the lisan formation is characterised by a high gypsum aragonite ratio and a low lithogenic content implying a regression of an initially high water level caused by reduced water input in the following interval ca 45 36 cal ka bp two low water stands are marked by higher salt concentrations after recovery and a period of higher water level the lake lisan era ends with a strong regression at around 16 cal ka bp this date coincides with the period when lake van eastern turkey also fell dry thus marking a strong drought signal in the entire near east the overlying damya formation containing more lithogenics records lake level fluctuations at around 300 m b s l the existence of a north south precipitation gradient as present today is indicated by increasing sr ca ratios in aragonite and a decreasing lithogenic content in a n s direction secondary gypsum formed diagenetically and aragonite and low mg calcite was transformed into high mg fe calcite

reconstructing low levels of lake lisan by correlating fan delta and lacustrine deposits abstract reconstruction of paleo shorelines of lake lisan the late pleistocene precursor of the dead sea is based on sequence stratigraphy of fan delta and lacustrine deposits that are exposed at the perazim valley southwest of the dead sea the shoreline sediments are physically correlated with lacustrine aragonites their ages are determined by u series dating to establish a lake level curve for the time interval between 55 and 35 kyr during most of this period lake lisan was at a relatively low level which fluctuated between 280 and 290 m below sea level m bsl the minimum lake stand 330 m bsl was reached at 47 kyr and lasted for 3 4 kyr this episode is marked by a depositional hiatus in the section and formation of an erosional channel the studied period correlates with the global marine isotope stage 3 the low stand of lake lisan during most of this period indicates relative dry climatic conditions in the region

reevaluation of the lake sediment chronology in the dead sea basin israel based on new 230th u dates the dead sea is surrounded by chemical and detrital sediments that were deposited in its larger precursor lakes lake samra and lake lisan the sedimentary history of these lakes was recon structed by means of 230th234u ages of 30 samples mostly of argonite laminae from 8 columnar sections up to 110 km apart the general validity of the ages was demonstrated by subjecting them to tests of internal isotopic consistency agreement with stratigraphic order and concordance with 14c ages in the south only the part of the samra formation older than 170 000 yr is exposed while the aragonite detritus rhythmites found in the central and northern region are generally younger than 120 000 yr the lisan formation started accumulating about 63 000 yr b p with the clay and aragonite beds in the south central area reflecting a rise in water level to at least 280 m the upper part of the lisan formation the aragonite rich white cliff member started accumulating about 36 000 yr b p the lake probably reached its highest level sometime after this based on the ages of lisan sediments preserved in the southernmost reaches of the basin

extracting holocene paleohydrology and paleoclimatology information from modern extreme flood events an example from southern california abstract the extraction of paleohydrological and paleoclimatological information from a modern hydrological system shown to represent unique and extreme hydroclimatological conditions is illustrated by an example from the mojave river drainage basin in southern california the mojave river allows only the most extreme floods to reach its terminal basin in the silver lake playa and to form ephemeral lakes all the other floods are lost by transmission into the alluvial aquifer along its 200 km channel this filtering out of regular floods by the river provides an essential tool in establishing a physical link between atmospheric and hydrologic conditions we demonstrate such a link between anomalous present day atmospheric circulation patterns over the north pacific ocean extreme storms in southern california that produced the heaviest precipitation on record the largest floods of record in the mojave river watershed and ephemeral lakes in its terminal playa this physical link determines the possible cause of the formations of perennial short duration shallow lakes in silver lake playa during the late holocene and characterizes the hydroclimatic conditions that prevailed during these lacustrine episodes hydrological simulations of this river and its filtering character demonstrate that these lakes could have formed only if the most extreme modern storms and floods were more frequent in at least an order of magnitude during specific time episodes we conclude that such extreme hydroclimatic conditions occurred more frequent in past episodes during which the holocene lakes formed in turn this conclusion indicates that the cause of these storms and floods i e the anomalous atmospheric circulation pattern must have been more frequent this research outlines a way to extract information on holocene climates in hydrologic settings that demonstrate a unique cause and effect relationship

late quaternary lacustrine deposits of the dead sea basin high resolution sequence stratigraphy from downhole logging data abstract sequence architecture and depositional sequences of the quaternary lacustrine succession deposited in the northern dead sea sub basin were examined using logging data collected during the 2010 2011 icdp campaign methods borrowed from sequence stratigraphy techniques were used to investigate the characteristics of sediments deposited in the central part of the northern lake high resolution wire logging data combined with a detailed lithological description of the icdp 5017 1 a deep borehole were used to examine depositional systems and related processes controlling their formation analysis of sedimentary stacking patterns and stratal surfaces within the late pleistocene holocene lacustrine succession revealed 10 depositional sequences it was possible to identify key stratal boundaries and to discern between three sedimentary stacking patterns interpreted here as representing lowstand systems tracts lst transgressive systems tracts tst and highstand systems tracts hst examined together they may be interpreted in terms of relative lake level changes on the basis of the stratigraphic analysis complemented with new age dating this article presents a record of the sediment accumulation pattern and a relative lake level curve reconstructed for the last ca 225 ka results show that stratigraphic units and depositional and erosional surfaces examined in the deep 5017 1 a borehole can be correlated to the proximal area of the basin this means that changes in relative lake levels were generally synchronous and uniform across the dead sea basin the creation of accommodation space in the northern dead sea was found to generally be in phase with paleoclimatic modulating lake levels and not due to tectonics

response to comment on dead sea drawdown and monsoonal impacts in the levant during the last interglacial epsl 412 235 244 2015

sources and transport routes of fine detritus material to the late quaternary dead sea basin abstract the sources and routes of transport of fine detritus material fdm to the lakes filling the late quaternary dead sea basin were studied by petrographic mineralogical grain size chemical and sr nd isotope analyses on sediments of the late quaternary lacustrine formations including river flood material dust and loess from the lake watershed the lacustrine formations comprise two sedimentary facies one that consists of alternating laminae of primary aragonite and silty detritus material aad facies and another that consists mainly of laminated detritus particles and generally lacks aragonite ld facies the aad facies characterizes the glacial intervals e g mis2 and 4 when lake levels were high while the ld facies characterizes interglacials e g mis1 5 and warmer glacial intervals e g mis3 when lake levels were low the detritus of both aad and ld facies show similar mineralogy mainly quartz and calcite grains with minor feldspars and clays but distinct grain sizes 8 10 m and 50 60 m respectively and distinct 87 sr 86 sr and end 0 711 0 712 and 7 to 8 versus 0 709 0 710 and 5 respectively the aad and ld fdm comprise desert dust of mixed granitic basaltic composition that was blown from the sahara desert and from the nile delta to the northern negev desert e g the loess deposits and the judean mountains bordering the dead sea basin mainly during glacial intervals along with enhanced mediterranean rain fronts the aad fdm reflects an enhanced transport of saharan granitic dust to the vicinity of the lake mainly during glacials the ld fdm was recycled from the loess surface cover of the negev desert mainly during interglacials and warm glacial intervals

u th dating of lake lisan late pleistocene dead sea aragonite and implications for glacial east mediterranean climate change u series dating can be an effective means to obtain accurate and precise ages on quaternary carbonates however most samples require a correction for u and th in admixed detritus this complication is often addressed through generation of u th isochrons requiring analyses of several coeval samples in addition presence of water derived hydrogenous th in the carbonate can cause inaccuracies in isochron ages this study reports a high resolution u series chronology of sediments deposited by lake lisan the last glacial precursor of the dead sea the strategy employed combines multiple measurements from a few stratigraphic heights and fewer analyses from many heights in a single described and measured section the resulting chronology is based on ages at 22 heights in a 40 m thick section covering the interval of 70 14 calendar ka bp the effects of admixed detritus are evaluated using trace elements nearly pure aragonite samples indicated by very low abundances of insoluble elements such as nb and zr were found to contain hydrogenous th which causes the uncorrected u 230th age of a modern sample to be 2 5 ka nevertheless accurate ages have been obtained by correcting for the detrital and aqueous interferences the resulting ages are in stratigraphic order and their accuracy is evidenced by consistency of lisan formation u series and 14c ages with the coral based calendar radiocarbon age calibration the u th ages provide a context to unravel the limnological history of lake lisan boundaries between the lower middle and upper stratigraphic units correspond to the mis 4 3 and 3 2 transitions respectively during mis 2 and 4 the lake generally showed a stable two layer configuration and a positive fresh water balance reflected by deposition of laminated aragonite detritus dry intervals during mis 2 and 4 are indicated by thick gypsum layers and an inferred depositional hiatus which are temporally associated with heinrich events h1 at 17 ka and h6 at 65 ka respectively during mis 3 the lake level was unstable with intermittent dry periods indicated by abundant clastic layers and a significant hiatus between 43 49 ka clastic layers are associated with dansgaard oeschger events during mis 3 and indicate lake level declines during abrupt northern hemisphere warmings overall the climate of the eastern mediterranean region shows a strong linkage to the northern hemisphere climate with increasing lake size and stability during cold periods and fluctuations and dessication during warmings and heinrich events

fluvial response to an historic lowstand of the great salt lake utah understanding fluvial adjustments to base level changes benefits the fields of sequence stratigraphy geomorphology and petroleum geology this investigation is a modern case study of the channel dynamics of lee creek and the goggin drain two streams that are part of the jordan river drainage into the endorheic great salt lake of northern utah a lacustrine system that has experienced multiple decadal scale base level changes since 1965 the lake level has fluctuated in elevation more than 6 m transitioning from an historic lowstand 1284 m a s l and in 2009 2010 approaching an historic lowstand this study uses detailed aerial images fieldwork and lidar data to link the modern geomorphology and channel hydraulics to specific variations in sediment transport channel form and avulsion behavior although lee creek and the goggin drain are situated only a few kilometers apart and share similar shore zone gradients substrates and vegetation patterns and have been subjected to the same changes in lake level their channel forms have evolved very differently differences in discharge patterns are likely the most influential factor causing the meandering form of lee creek and the braiding channel of the goggin drain despite the differences in discharge total sediment eroded from the two streams is comparable and can be attributed to similar stream power unit stream width in the two streams although lee creek has not recently been avulsive three major avulsions of the goggin drain have taken place since 1965 two possible styles of avulsion are interpreted an allogenic response to changing base level and an autogenic response dictated by channel morphology and hydraulics despite a wealth of available information avulsions cannot be unequivocally attributed to one style or another caution should be used when attempting to link the complex process of avulsion to causal mechanisms copyright 2011 john wiley sons ltd

dating large infrequent earthquakes by damaged cave deposits the long term recurrence patterns of past earthquakes are of considerable consequence for hazard assessments and have implications for earthquake physics we introduce a rigorously dated record of earthquakes from an extensive number of well preserved pre seismic and postseismic precipitates from caves located off the dead sea transform we dated events directly at the paleoseismic contact by means of a novel correlation method with the oxygen isotope record of the speleothems recovered in one of the caves within the 185 k y covered we dated 38 seismite samples these stem from 13 18 earthquakes with a mean recurrence interval of 10 14 k y we show that the deformational events dated in the study caves complement independent near fault paleoseismic records by tem poral correlation with the earthquakes recorded therein this opens up a significant new avenue of earthquake research that will provide precise dating and observational con straints on large infrequent earthquakes

bathymetry of lake lisan controls late pleistocene and holocene stream incision in response to base level fall abstract this paper examines the millennial scale evolution of the longitude profile of nahal wadi zin in the dead sea basin in the northern arava valley israel nahal zin has incised 50 m into relatively soft late pleistocene lake lisan sediments incision was forced by the regressive 10 km lake level fall of a total of 200 m of lake lisan from its highest stand at 25 ka and exposure of the lake floor sediments to fluvial and coastal processes alluvial cut terraces of the incising channel are well preserved along the 17 5 km of the lowermost reach of nahal zin at its outlet into the dead sea basin nahal zin deposited a holocene alluvial fan at the base of a 10 80 m high escarpment in unconsolidated sediments the escarpment is associated with the amazyahu fault which forms the southern structural boundary of the present dead sea basin geomorphic mapping optically stimulated luminescence osl ages and soil stratigraphy allowed correlation of terrace remnants and reconstruction of several past longitudinal profiles of nahal zin and its incision history together with the published lake level chronology these data provide an opportunity to examine stream incision related to base level lowering at a millennial scale osl ages of the terraces fit relatively well with the established lake level chronology and follow its regression and fall for a few thousands of years the longitudinal profile response to the lake level fall was downstream lengthening onto the exposed former lake bed most of the incision 40 m occurred later when the lake level reached the top of the amazyahu fault escarpment and continued to drop the incision was a relatively short episode at about 17 ka and cut through this escarpment almost to its base the fast incision its timing and the profiles of the incising channels indicate that the escarpment was an underwater feature and was not formed after the lake retreated this fairly simple scenario of regressive lake level fall and knickpoint exposure and incision is modeled here using a one dimensional numerical incision model based on a linear diffusion equation the calculated diffusion coefficient fits earlier results and data obtained from other streams in the area and confirms the upscaling of this simple model to the millennial scale

modern extreme storms and the rainfall thresholds for initiating debris flows on the hyperarid western escarpment of the dead sea israel intense rainstorms cause debris flows on escarpments in hyperarid environments in contrast with more temperate environments there have been no direct observations on rainfall intensities and durations required for initiating debris flows in hyperarid environments here we report rainfall volume and intensities acquired by gauge and radar measurements for two successive storms along the hyperarid the first of the two analyzed storms occurred on 2 november 1995 during this storm two convective cells rained sequentially within a 5 h period at the lower reaches of the nahal david and the nahal arugot that dissects the western escarpment of the dead sea israel this storm triggered debris flows in 38 small 2 and high gradient drainage basins along the escarpment total rainfall volume and spatial distribution were determined by 10 cumulative rain gauges that were also used to calibrate rainfall intensity distributions from radar data for this storm region and landscape rainfall intensities exceeding 30 mm h for a duration of 1 h were required to initiate debris flows a second storm in the same area on 17 18 october 1997 allowed the evaluation of the results determined from the 1995 storm in this second more regional storm maximum rainfall intensities were 19 27 mm h for a duration of 45 min these values lower than the 30 mm h minimal threshold defined in the previous storm are consistent with the occurrence of only three debris flows the small number of debris flows resulted from the concentration of the highest intensities of rainfall on the desert plateau and not directly on top of the canyon walls most first to third order basins draining the dead sea escarpment contain evidence of zero to three late holocene 30 mm h and durations of at least 1 h the small number of debris flows that has occurred during the late holocene indicates that such events are rare at the scale of individual drainage basins