climate swings in the northern red sea over the last 150 000 years from end and mg ca of marine sediments abstract the end and mg ca compositions of terrigenous material from a meridional transect of seven marine sediment cores located between the northern red sea and the gulf of aqaba together with modern dust sample compositions reveal the temporal and spatial changes in precipitation and dust sources over the last 150 kyrs and are further used to discuss the late quaternary climate history of this region two recent glacial periods marine isotopes stages mis 6 and 2 are characterized by low end values associated with a saharan dust source 12 while mg ca ratios suggest increased transport of dust containing authigenic clays during the last deglacial which most likely originated from the arabian peninsula by contrast mis5e sediments are characterized by an abrupt basin wide shift of end values toward the local arabian nubian shield end member 2 that are exposed around the red sea this shift stems from intense fluvial events and is coeval with other regional paleo precipitation records that all point to an extensive northward shift of precipitation from the tropics during mis5e considering model simulations and regional precipitation dynamics we conclude that although the african summer monsoon probably intensified and extended somewhat northward during mis5e it was not the driver of significant precipitation and the main contribution of precipitation to the northern red sea was due to increased frequency and possible intensity of tropical plumes and red sea troughs that triggered massive fluvial floods within the red sea catchment considering mis5e as an analogue to a future warmer world this currently hyperarid region could be exposed over the coming decades to an increased impact of extreme rainfall events with critical implications for water availability and infrastructure sustainability

charge transfer and in cloud structure of large charge moment positive lightning strokes in a mesoscale convective system 1 lightning observations in the very high frequency band and measurements of ultra low frequency magnetic fields are analyzed to investigate the charge transfer and in cloud structure of eight positive cloud to ground cg strokes in a mesoscale convective system although no high altitude images were recorded these strokes contained large charge moment changes 1500 3200 c km capable of producing nighttime sprites even though the convective region of the storm was where the flashes originated and where the cg strokes could occur the charge transferred to ground was mainly from the stratiform region the post stroke long continuing currents were connected to highly branched negative leader extension into the stratiform region while the storm dissipated the altitude of negative leader propagation in the stratiform area dropped gradually from 8 to 5 km indicating that in some and perhaps all of these strokes it was the upper positive charge in the stratiform region that was transferred

sand dunes as a major proximal dust source for late pleistocene loess in the negev desert israel grain size analyses of three hilltop primary eolian loess sequences in the negev desert southern israel show a bimodal grain size distribution at 50 60 m and 3 8 m using analyses of mineralogy and osl ages we demonstrate that the coarse mode is composed mostly of quartz grains and its relative magnitude increases regionally with time suggesting an enhancement of a time transgressive proximal dust source compared to a distal saharan fine grain dust the only proximal dust source for large amount of coarse silt quartz grains is the sands that advanced into sinai and the negev concurrently with the loess accretion during the late pleistocene as a result of the exposure of the mediterranean shelf we therefore propose that the coarse silt quartz grains were formed through eolian abrasion within the margins of an advancing sand sea this relationship between desert sand seas as a source for proximal coarse dust and desert margin loess deposits can be applicable to other worldwide deserts such as northern africa china and australia

transient luminous events above two mesoscale convective systems storm structure and evolution 1 two warm season mesoscale convective systems mcss were analyzed with respect to their production of transient luminous events tles mainly sprites the 20 june 2007 symmetric mcs produced 282 observed tles over a 4 h period during which the storm s intense convection weakened and its stratiform region strengthened tle production corresponded well to convective intensity the convective elements of the mcs contained normal polarity tripole charge structures with upper level positive charge 40 c midlevel negative charge 20 c and low level positive charge near the melting level in contrast to previous sprite studies the stratiform charge layer involved in tle production by parent positive cloud to ground cg lightning resided at upper levels this layer was physically connected to upper level convective positive charge via a downward sloping pathway the average altitude discharged by tle parent flashes during tle activity was 8 2 km above mean sea level msl 25 c the 9 may 2007 asymmetric mcs produced 25 observed tles over a 2 h period during which the storm s convection rapidly weakened before recovering later unlike 20 june tle production was approximately anticorrelated with convective intensity the 9 may storm which also had a normal tripole in its convection best fit the conventional model of low altitude positive charge playing the dominant role in sprite production however the average altitude discharged during the tle phase of flashes still was higher than the melting level 6 1 km msl 15 c based on these results it is inferred that sprite production and sprite parent positive charge altitude depend on mcs morphology

electrical structure in thunderstorm convective regions 1 mesoscale convective systems electric field e soundings through convective regions of mesoscale convective systems mcss are examined in this paper ten e soundings through updrafts in mcs convective regions and five soundings in mcs convective regions outside updrafts are used to show that a typical electrical structure exists in this region these 15 e soundings plus one other previously published sounding which is included in this analysis comprise all known soundings in the convective region of mcss the basic charge structure identified in mcs updrafts consists of four charge regions alternating in polarity with the lowest region positive and the highest region negative the basic charge structure outside updrafts in mcs convective regions has six charge regions alternating in polarity with a positive charge region lowest maximum e magnitudes of both polarities are larger and are located at lower heights in soundings outside updrafts compared to those within updrafts excepting the upper positive charge inferred charge regions are shallower and have larger charge densities outside updrafts the center of the main negative charge is lower and warmer outside updrafts 5 5 km 6 2 c than within updrafts 6 9 km 15 7 c these features inside and outside updrafts are incorporated in a new conceptual model of mcs convective region charge structure also an expanded conceptual model is developed using previously published data from other parts of mcss this more complete conceptual model shows the typical electrical charge airflow and reflectivity features in the stratiform region the transition zone and the convective region of midlatitude mesoscale convective systems

integrated multi site u th chronology of the last glacial lake lisan abstract we present a new integrated multi site chronology for lake lisan which occupied the dead sea basin and jordan valley during the last glacial period 70 14 kka marine isotope stages 4 3 2 the dead sea basin lacustrine deposits are unique among closed basin sediments in that they formed in a deep hypersaline water body that precipitated primary aragonite which is amenable to radiometric dating by u series providing a solid basis for studies of the relationship of middle east climate to other changes in the high latitudes or the tropics the application of u th dating for lacustrine carbonates requires corrections for detrital u and th and hydrogenous initial 230th here we followed an iterative approach in which we evaluate the composition of the detrital contamination independently for every set of coeval samples to determine the corrected ages these were further filtered and combined with lithological limnological considerations which were used to construct age height models for all studied stratigraphic sections finally the ages of stratigraphic tie points were used to integrate the individual age height models into a unified chronology the resulting chronological framework indicates that the ages of several primary gypsum units associated with catastrophic lake level drops correspond with the timing of heinrich events in the north atlantic thus a final iterative step involves refining the ages of lisan gypsum events based on the ages of heinrich events 6 5 5a 4 and 1 this approach yields an unprecedented basin wide unified event anchored chronology for the lisan formation with typical age uncertainties ca 1000 2000 years 95 confidence limit across the entire last glacial well below those typically related to individual u th and radiocarbon dating of dirty carbonates from similar time intervals the results can be further extrapolated to new sites and serve as a geochronometric reference for the reconstruction of the limnological history of lake lisan

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

effects of charge and electrostatic potential on lightning propagation 1 three dimensional lightning mapping observations are compared to cloud charge structures and electric potential profiles inferred from balloon soundings of electric field in new mexico mountain thunderstorms for six individual intracloud and cloud to ground flashes and for a sequence of 36 flashes in one storm the comparisons consistently show good agreement between the altitudes of horizontal lightning channels and the altitudes of electric potential extrema or wells lightning flashes appear to deposit charge of opposite polarity in relatively localized volumes within the preexisting lower positive midlevel negative and upper positive charge regions associated with the potential wells the net effect of recurring lightning charge deposition at the approximate levels of potential extrema is to increase the complexity in the observed storm charge structure the midlevel breakdown of both normal intracloud flashes and negative cloud to ground flashes is observed to be segregated by flash type into the upper and lower parts of the deep potential well associated with the midlevel negative charge the segregation is consistent with perturbations observed in the bottom of the negative potential well due to embedded positive charge that was probably deposited by earlier flashes it is also consistent with an expected tendency for vertical breakdown to begin branching horizontally before reaching the local potential minimum the joint observations reconcile the apparent dichotomy between the complex charge structures often inferred from balloon soundings through storms and the simpler structures often inferred from lightning measurements

palaeoclimate interpretations of late pleistocene vegetated linear dune mobilization episodes evidence from the northwestern negev dunefield israel abstract the vegetated linear dune vld field of the northwestern nw negev desert situated at the downwind eastern end of the northern sinai nw negev erg constitutes an ideal setting for dating and interpreting its late quaternary dune encroachment episodes this study builds upon the results of roskin et al age origin and climatic controls on vegetated linear dunes in the northwestern negev desert israel quaternary science reviews 30 2011 1649 1674 that presented the stratigraphy of 35 sections and 97 optically stimulated luminescence osl ages from the nw negev dunefield here we refine our analysis of the negev late pleistocene dune mobilizations and stabilizations and interpret their palaeoclimatic controls in light of regional and global sediment records and proxies while initial dune encroachment into and stabilization in the nw negev took place during the last glacial maximum lgm at 23 18 ka spatial and statistical analyses of the osl dataset suggest that since the lgm negev dune activity was concentrated in two significant mobilization stabilization episodes a main episode at 16 13 7 ka and a minor one at 12 4 11 6 ka when the dunes reached their maximum spatial extent and stabilized these episodes include rapid dune encroachment and accretion events and coincide with the heinrich 1 and younger dryas cold events respectively the late pleistocene sand transporting winds were characterized by a westerly direction that resulted in west east vld elongation dune mobilizations may have occurred in response to wintertime east mediterranean cyclonic systems that brought storms of rainfall and strong winds the rapid dune mobilization events and their concurrence with the heinrich 1 and younger dryas cold events suggest a more global control despite the rainfall the elongating vlds were probably sparsely vegetated because of the high wind power their stabilization resulted from a decrease in storminess with the onset of a more arid holocene climate other global low latitude dune mobilizations and stabilizations are concentrated at the end of the late pleistocene leading us to suggest that these were also controlled mainly by global cold events and subsequent changes in windiness the recurring discontinuous aeolian sedimentation pattern found in osl dated vlds provides new and important chronological and sedimentological insight into prominent dune mobilization and stabilization processes the suggested link between global drops in cold event windiness and low latitude dune stabilization episodes emphasizes the prevalence of winds over aridity regarding major dune mobilizations for low latitude dunes even if vegetated

the magnitude timing and abruptness of changes in north african dust deposition over the last 20 000 yr reconstructions of eolian dust accumulation in northwest african margin sediments provide important continuous records of past changes in atmospheric circulation and aridity in the region existing records indicate dramatic changes in north african dust emissions over the last 20 ka but the limited spatial extent of these records and the lack of high resolution flux data do not allow us to determine whether changes in dust deposition occurred with similar timing magnitude and abruptness throughout northwest africa here we present new records from a meridional transect of cores stretching from 311 nt o 191n along the northwest african margin by combining grain size endmember modeling with 230 th normalized fluxes for the first time we are able to document spatial and temporal changes in dust deposition under the north african dust plume throughout the last 20 ka our results provide quantitative estimates of the magnitude of dust flux changes associated with heinrich stadial 1 the younger dryas and the african humid period ahp 11 7 5 ka offering robust targets for model based estimates of the climatic and biogeochemical impacts of past changes in north african dust emissions our data suggest that dust fluxes between 8 and 6 ka were a factor of 5 lower than average fluxes during the last 2 ka using a simple model to estimate the effects of bioturbation on dust input signals we find that our data are consistent with abrupt synchronous changes in dust fluxes in all cores at the beginning and end of the ahp the mean ages of these transitions are 11 870 2 ka 1s and 4 970 2 ka respectively

grain size control on sr nd isotope provenance studies and impact on paleoclimate reconstructions an example from deep sea sediments offshore nw africa five sediment cores from offshore nw africa were analyzed for strontium and neodymium isotope ratios to reconstruct temporal variations in continental weathering regimes sediments were taken from three time slices with well known and distinctive environmental conditions present day dry and warm similar to 6 ka wet and warm and similar to 12 ka dry and cold terrigenous sediment samples were split into two size fractions to distinguish between the two dominant transport mechanisms offshore nw africa fluvial 0 10 mu m and aeolian 10 40 mu m sr isotope data record evidence of marked grain size control with higher isotopic ratios in the fine fraction in contrast epsilon nd values are largely unaffected by grain size minor variability in nd isotope data at each sampling site indicates near constant sources of terrigenous matter over the last similar to 12 ka variations in sr isotope ratios are interpreted to reflect major changes in the evaporation precipitation balance we suggest that the sr nd isotope data record a latitudinal shift of the northern limit of the african rainbelt and associated wind systems causing changes in the humidity and rate of chemical weathering over nw africa while hyperarid conditions prevailed similar to 12 ka more humid conditions and intensified monsoonal rainfall at similar to 6 ka resulted in greater breakdown of easily weathered k bearing phases and increased sr 87 sr 86 in the detritus in late holocene times the monsoonal circulation diminished resulting in a return to arid conditions our results clearly show that it is of vital importance in paleoenvironmental studies to carry out isotopic analyses on individual sediment fractions that were carried to the studied deposition site by distinct sediment transport mechanisms if isotopic analyses are carried out on bulk sediments the observed variability in isotopic values most likely represents changes in the particle size and mixing proportions of the sediment subpopulations

coordinated observations of sprites and in cloud lightning flash structure 1 the temporal and spatial development of sprite producing lightning flashes is examined with coordinated observations over an asymmetric mesoscale convective system mcs on 29 june 2011 near the oklahoma lightning mapping array lma sprites produced by a total of 26 lightning flashes were observed simultaneously on video from bennett colorado and hawley texas enabling a triangulation of sprites in comparison with temporal development of parent lightning in particular negatively charged stepped leaders in three dimensional space in general prompt sprites produced within 20 ms after the causative stroke are less horizontally displaced typically 30 km however both prompt and delayed sprites are usually centered within 30 km of the geometric center of relevant lma sources with affinity to negative stepped leaders during the prior 100 ms interval multiple sprites appearing as dancing jumping events associated with a single lightning flash could be produced either by distinct strokes of the flash by a single stroke through a series of current surges superposed on an intense continuing current or by both our observations imply that sprites elongated in one direction are sometimes linked to in cloud leader structure with the same elongation and sprites that were more symmetric were produced above the progression of multiple negative leaders this suggests that the large scale structure of sprites could be affected by the in cloud geometry of positive charge removal based on an expanded dataset of 39 sprite parent flashes by including more sprites recorded by one single camera over the same mcs the altitude above mean sea level msl of positively charged cloud region tapped by sprite producing strokes declined gradually from 10 km msl 35 c to around 6 km msl 10 c as the mcs evolved through the mature stage on average the positive charge removal by causative strokes of sprites observed on 29 june is centered at 3 6 km above the freezing level or at 7 9 km above ground level

deglacial sea level record from tahiti corals and the timing of global meltwater discharge the timing of the last deglaciation is important to our understanding of the dynamics of large ice sheets1 and their effects on the earth s surface2 3 moreover the disappearance of the glacial ice sheets was responsible for dramatic increases in freshwater fluxes to the oceans which probably disturbed the ocean s thermohaline circulation and hence global climate4 7 sea level increases bear witness to the melting of continental ice sheets but only two such records from barbados8 9 and new guinea10 11 corals have been accurately dated but these corals overlie active subduction zones where tectonic movements are large and often discontinuous especially in new guinea so the apparent sea level records may be contaminated by a complex tectonic component here we date fossil corals from tahiti which is far from plate boundaries and thus is likely to be tectonically relatively stable and remote from the locations of large former ice sheets the resulting record indicates a large sea level jump shortly before 13 800 calendar years bp which corresponds to meltwater pulse 1a in the barbados coral records8 9 the timing of this event is more accurately constrained in the tahiti record revealing that the meltwater pulse coincides with a short and intense climate cooling event12 15 that followed the initiation of the bolling allerod warm period12 16 but preceded the younger dryas cold event by about 1 000 years

the sedimentary and environmental history of tortonian messinian lakes at the east mediterranean margins northern israel abstract during the late neogene the east mediterranean margins of the levant went through major morphological changes due to tectonic activity associated with the dead sea transform fault the regional fluvial systems inverted their flow direction from westward towards the mediterranean to eastward towards the jordan valley tectonic basins that developed at that time in northern israel were filled by lakes with intermittent connections to the sea the tectonic processes were accompanied by volcanism of alkali basalts this study focuses on the evolution of sedimentary volcanic sequences mainly included in the bira and gesher formations that were deposited in lacustrine and palustrine environments in northern israel the study presents a comprehensive dataset and interpretation integrating new and old lithological and paleontological records from outcrops and drill holes together with new petrographic and mineralogical data the bira formation of tortonian age which overlies the lower basalt unit consists mainly of lacustrine littoral limestone and dolostone and basinal marl sporadic occurrences of marine macrofauna indicate pulses of marine ingressions that reached the jordan valley depocenter where thick sequences of gypsum and salt were deposited the overlying gesher formation of messinian early zanclean age which has a similar lithology to that of the bira formation represents an environmental evolution from restricted shallow lakes into a larger lake or lakes and finally to shallow isolated water bodies the latter stage coincides with the messinian salinity crisis when climate became more arid in the levant pyroclasts and some lava flows recorded an ongoing volcanic activity during this period that intensified toward the eruption of the cover basalt unit that overlies the gesher formation overall the bira and gesher formations provide a detailed sedimentological tectonic and volcanic history of the continental margins of the east mediterranean and its connection to the tectonic evolution of basin associated with the dead sea transform fault

new high resolution ground based studies of sprites new observations of sprites cloud ionosphere luminous discharges above thunderstorms were made from the yucca ridge field station 20 km northeast of fort collins colorado on the night of july 11 12 1994 as part of a summer 1994 observing campaign the sprites appeared above a moderate mesoscale convective complex mostly over kansas at a range of about 270 km the sprites were observed with both wide field and telescopic image intensified ccd tv cameras a telescopic photometer system and a 1 to 50 khz band vlf sferics receiver this paper is based on five 1 s data intervals containing bright sprites smaller sprites and cloud and sky flashes telescopic tv images of bright sprites had a fan shaped upper plume with very fine features not well resolved by the tv but dendritic upward forked and vertically striated forms adjacent to these plumes and bright points of luminosity around the plume shaped regions many sprites consisted entirely of groups of vertically aligned striations which sometimes appeared to diverge from a common point of origin at cloud tops all sprites in the present data sample were preceded by a cloud to ground cg stroke with a coincident sferic and sky flash all cg strokes associated with sprites were positive and most were 100 ka or more inferred peak current from the photometer the duration of the cg induced sky flashes was about 3 ms and the additional sprite total light curve was also about 3 ms the puzzling feature that the total duration of tv images of sprites was often longer than the photometric values is discussed and an explanation given the sprites were attributed to strong negative charging following the positive cg stroke of a localized cloud top region which produced an intense electric field and a luminous discharge in the cloud ionosphere region the concept of break even electric fields suggested by mccarthy and parks may explain discharge initiation with moderate field strengths

the micromorphology of gypsum and halite in reg soils the negev desert israel gypsum and halite are the most common salts in reg soils developed on alluvial parent material under extremely arid conditions in the negev desert israel the aim of this paper is to document the changes in the micromorphology of these salts at different stages of reg soil development on two alluvial fan chronosequences the micromorphological analyses included thin section observations and scanning electron microscope and electron microprobe analyses in this arid soil environment gypsum and halite possess a variety of crystal forms which may change with depth in a single profile and or between profiles of different ages the variety of crystal forms results from changes in the microenvironmental conditions that occur in desert reg soils over time poikilitic lenticular gypsum is found in all reg soils and is distributed throughout the profiles the conditions needed for such crystals to form are high ionic impurities and deposition in a void system where space is not limiting microcrystalline alabastrine gypsum is only found in mature reg soils and is crystallized when the profile has high amounts of fine material and a well developed desert pavement in a well developed reg soil profile indicators such as a well developed desert pavement and high amounts of fine earth limit the leaching depth and cause gypsum deposition from supersaturated soil solutions under high evaporation rates close to the surface prismatic and fibrous gypsum are less common low amounts of prismatic gypsum are found in young and mature soils while fibrous gypsum is found only in mature soils in re cemented shattered gravel the halite crystal form is mainly cubic with low amounts of host material incorporated into the crystal it occurs predominantly in mature reg soil profiles through the crystallization from supersaturated soil solutions at the depth of maximum water penetration although the alabastrine prismatic and fibrous gypsum and cubic halite are deposited in a displacive manner no correlation was found between their occurrence and the distribution of shattered gravel in the soil profile

soils in the mediterranean region what makes them different mediterranean climates are characterized by winter rains with some months of excess rainfall over evatranspiration warm and dry summer months with moisutre deficits drying out soils and their annual vegetation xeric moisture regime they are found on western parts of all continents between the cooler temperature zone and the hot dry desert zone the largest mediterranean region surrounding the mediterranean sea extends over 4 300 000 km2 and exhibits a wide variety of soils and geo ecosystems characteristics landscape attributes are the high proportion of mountains with sleep slopes significant additions of saharan desert dust to practically all soils of the region and a large proportion of limestone and other calcareous rocks as soil parent materials characteristics soil behavior features are moderate weathering with pervection leaching lessivage of mostly 2 1 clays into b horizons xeralfs luvisols hematite induced reddening of the clays due to summer dehydration of free iron oxyhydroxides carbonate dissolution and reprecipitation with prevalence of calcic horizons xerolls calcisols in semiarid regions and development of vertisols mostly in lowlands where deep layers of swelling cracking clays have sedimented shallows soils on nearly bare slopes mostly a result of erosion subsequent to deforestation are frequent leptosols cambiosols inceptisols entisols red or brown mediterranean soils are no longer used as a separate classification group in modern well defined soil property controlled taxonomies soil taxonomy fao system but were partially replaced by duchaufour s term fersiallitic soils in some classification systems terra rossa continues to be used in some classification for hard limestone derived red soils mostly shallow the effects of man s past and current interference with the lanscape are pervasive in most regions and predictions for possible future effects on the soils and ecosystems due to greenhouse gas induced warming and rainfall change are partly negative partly still too uncertain

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

100 000 years of african monsoon variability recorded in sediments of the nile margin abstract multiproxy analyses were performed on core ms27pt recovered in hemipelagic sediments deposited on the nile margin in order to reconstruct nile river palaeohydrological fluctuations during the last 100 000 years the strontium and neodymium isotope composition of the terrigenous fraction and the major element distribution reveal large and abrupt changes in source oscillating between a dominant aeolian saharan contribution during arid periods and a dominant nile river contribution during pluvial periods iron content shows a strong correlation with strontium and neodymium isotopes this allows the use of a high resolution continuous fe record as a proxy of blue nile sediment input over the last 100 000 years the detailed fe record with approximately 10 years resolution during pluvial periods is consistent with subtropical african records of well dated lake level fluctuations and thus constitutes a first continuous high resolution record of the east african monsoon regime intensity over ethiopia the detailed fe record shows the two main known pluvial periods attributed to strengthening of the african monsoon over ethiopia the nabtian period from 14 to 8 ka cal bp and the saharan period from 98 to 72 ka bp for the first time the last glacial period marine isotope stage mis 2 3 and 4 is documented with a continuous record showing large oscillations between high and low east african palaeo monsoon regimes the end of the nabtian period occurred at 8 ka in core ms27pt i e much earlier than on the east equatorial african region where it ended around 5 5 ka we interpret this as evidence that the southward shift of the rain belt occurred 3000 years earlier over the eastern ethiopian highland and propose that the gradual southward migration of the rain belt was associated with highly variable intensity and longer rainy seasons from 8 to 5 ka during the last glacial period two wet periods are present around 60 50 ka bp and 38 30 ka bp these two humid periods are in phase with the rise of atmospheric ch4 concentrations suggesting that wetland tropical african area was one of the sources of the atmospheric ch4 during the mis 3 during the last glacial maximum and mis 4 high saharan aeolian influxes in phase with records of aeolian dust deposited in east antarctica are documented this study highlights the importance of reconstructions of monsoon rainfall fluctuation at high temporal resolution to better understand the link between low and high latitude climate variability at millennial timescales

northward intrusions of low and mid latitude storms across the saharo arabian belt during past interglacials the rain regime of the levant during the late quaternary was controlled primarily by mediterranean cyclonic systems associated with north atlantic climate shifts lake levels in the dead sea basin have been robust recorders of the regional hydrology and generally indicate highstand wet conditions throughout glacial intervals and lowstands dry during interglacials however sporadic deposition of travertines and speleothems occurred in the negev desert and arava valley during past interglacials suggesting intrusions of humidity from southern sources probably in association with enhanced activity of mid latitude red sea synoptic troughs and or low latitude tropical plumes the southerly incursions of wetness were superimposed on the long term interglacial levantine arid conditions as refl ected by the current prevailing hyperaridity and could have had an important impact on human migration through the red sea dead sea corridor

distribution of natural and anthropogenic lead in mediterranean soils abstract the concentrations and isotopic composition of pb have been combined with a selective sequential dissolution procedure to track the distribution of anthropogenic and natural pb in the soil of semiarid climate and the penetration pathway of petrol pb within the soil profile soil samples were collected from soil profiles adjacent to a major highway 8 23 m and from soil profiles 500 m away from the same highway the selective sequential dissolution procedure was used to determine the distribution of pb between the different soil components soil carbonate organic matter fe oxides and hydrous oxides and aluminosilicates natural pb is associated mainly with aluminosilicates 60 and fe oxides 30 and only a small fraction with the soil carbonate and organic matter 10 in contrast to the distribution of natural pb the distribution of anthropogenic pb which accumulates mainly in the upper part of the soil profile is 40 with the soil carbonate 10 with organic matter 35 with fe oxides and only 15 with aluminosilicates on the basis of concentration and isotopic composition of total pb the deeper horizon of the roadside soil 10 30 cm and the soil sampled 500 m from the highway seem uncontaminated however the isotopic composition of the labile components in the soil pbcarb pborg and pbfe ox indicates that these soils are actually contaminated this contamination implies that over the period of vehicle pollution 40 yr petrol pb has penetrated through the entire roadside soil profile 25 30 cm furthermore pb isotopes in aluminosilicates of the upper part of the roadside soil indicate that this pb too is anthropogenic measurements of pb concentration and isotopic composition in roadside soil profiles sampled in 1997 and archived samples collected at the same location in 1982 provided a unique opportunity to trace petrol pb penetration into the soil

pyrite textures and trace element compositions from the granodiorite hosted gold deposit at jonnagiri eastern dharwar craton india implications for gold mineralization processes

dust transport and synoptic conditions over the sahara arabia deserts during the mis6 5 and 2 1 transitions from grain size chemical and isotopic properties of red sea cores abstract the red sea situated between the sahara and arabia deserts is a natural trap for fine grained particles transported by winds and floods from weathered materials in these deserts derived from the proterozoic crustal granitic and basaltic terrains and phanerozoic carbonates the accumulated fine particles provide valuable information on the climate conditions in the source regions and modes of atmospheric circulation over the red sea region here we report on the grain size mineralogy chemical composition and nd and sr isotope ratios of fine grained insoluble residues ir from acid leaching that were recovered from two deep sea cores kl23 and kl11 drilled in the northern and central red sea respectively we focus on the mis6 5 and mis2 1 transitions kl23 samples are closer to the sahara granitoids field and display significant variations during the mis6 5 transition between end of 7 to 2 and 87sr 86sr of 0 7096 to 0 7114 smaller variations occurred during the mis2 1 transition between end of 5 to 6 and 87sr 86sr of 0 7104 to 0 7118 the kl11 values are closer to the blue nile field which comprises mixtures of granitoid and basalt derived particles during the mis6 5 transition their end varies from 4 to 1 and in 87sr 86sr from 0 7059 to 0 7091 during periods equivalent to sapropels s5 and s1 both cores appear to converge to similar isotope ratios of e nd 2 and 87sr 86sr 0 7095 indicating derivation from the granitoid terrains of the arabian nubian shield occurring adjacent to the red sea and possibly distributed by runoff in terms of synoptic conditions the data indicate that during glacials dust was blown to the northern red sea from the northern sahara desert in association with the mediterranean winter cyclones and to the central red sea from the ethiopian plateau by southern winds that are associated with monsoonal circulation during interglacials especially sapropel intervals monsoonal rains caused erosion and flooding at the arabian nubian shield margins of the red sea during the heinrich events associated with the studied intervals h11 and h1 dust from mixed basaltic granitic terrains was blown from all of the regional sources in the red sea region reflecting severe regional aridity and transport of dust by regional winds when monsoonal activity and mediterranean cyclone activity were weak

on the series of cg lightning strokes in dancing sprite events in dancing sprite events sprite entities and groups appear in rapid succession together with a corresponding series of parent lightning strokes dancing sprite events including a case with possible sprite rebrightening were recorded on video simultaneously from two observation sites above a mesoscale convective system in central europe on the night of 6 august 2013 joint analysis of triangulated locations of sprite elements position type and peak current of lightning strokes from the linet lightning detection network database and current moment waveforms deduced at the hylaty station poland showed that subsequent sprite parent lightning strokes occurred no further than 21 km from the closest preceding sprite entity in the cases analyzed in this study additionally it was found that longer sprite delay times tend to correspond to larger sprite location offsets from the parent cg stroke these observations the occurrence of cg lightning stroke and sprite sequences as well as sprite sprite delay times and displacements can be explained if cg strokes are part of one extended lightning flash a corresponding production mechanism based on previous findings on the formation of sprite producing and general cg lightning discharges is suggested plain language summary in dancing sprite events sprites appear in rapid succession together with a corresponding series of parent lightning strokes dancing sprite events were recorded on video simultaneously from two observation sites above an extended thunderstorm system in central europe on the night of 6 august 2013 comparison of triangulated sprite locations and the locations of corresponding lightning activity revealed that subsequent sprite parent lightning strokes occurred below or relatively near the location of the closest preceding sprite entity in the examined cases in this paper a mechanism is suggested for the development of lightning flashes that produce dancing sprites the proposed mechanism accounts for prompt and delayed sprites relative to their parent lightning stroke highlights the role of the variation of lightning current in sprite production and can explain the observed closeness of the next cg lightning stroke to the area of previous sprites

electrical evolution during the decay stage of new mexico thunderstorms 1 the electric field e at the ground beneath a thunderstorm often exhibits an end of storm oscillation eoso during the storm s decay phase in which e typically undergoes three polarity changes over a period of 30 75 min to determine why the surface e oscillates the timing of the eoso polarity changes of a multicellular storm in new mexico has been compared to a series of balloon radar and lightning data three in situ balloon soundings provide vertical profiles of e and inferred charge regions just before and during the eoso these data have been compared to the evolving precipitation structure determined from orthogonal range height scans of two radars and to several other parameters including lightning mapping array data before the eoso began the storm had the typical electrical structure of the late mature stage estimates of the total charge magnitudes in each of the principal regions before and during the eoso ranged from 7 to 33 c the comparisons indicate that surface e polarity changes during the eoso were 1 primarily owing to the successive fallout of three of the four principal charge regions in the storm s mature stage charge structure modified by 2 the growth or decay of the charge regions as they descended and 3 changes in the screening charges at the upper and lower cloud boundaries more limited data from two other decaying storms indicate that similar in cloud evolution was probably occurring during their eosos

bulk composition of northern african dust and its source sediments a compilation abstract this paper presents a review of bulk compositional data of northern african dust and its potential source sediments and includes elemental isotope and mineralogical data northern african dust represents about one half of the total global atmospheric mineral dust burden and its uplift transport and deposition have strong impacts on climate and various terrestrial and marine ecosystems the chemical data set shows that an average northern african dust exhibits comparable si fe and mn contents with respect to the average composition of the upper continental crust is slightly depleted in the alkali metals k and na and enriched in ti and p however the complete data set yields clear evidence that northern african dust and its source sediments are compositionally heterogeneous on a regional scale and that this heterogeneity can be used to differentiate between major potential source areas on the basis of so called source markers an evaluation of these compositional fingerprints shows that the following parameters and especially their combination are effective in the discrimination of the most active source areas in northern africa ratio of ca mg fe wt calcite or carbonate content palygorskite occurrence and abundance illite kaolinite ratio nd 0 value and 87sr 86sr ratio for example the data set corroborates previous ideas which assign carbonate illite and palygorskite rich mineral dusts to north west ern source regions because most of the above listed source markers do not change substantially during transport even far traveled dusts may be assigned to specific potential source areas in northern africa some limitations of the presented data set are also discussed our compilation reveals some substantial gaps in the knowledge of the composition of source sediments and mineral dusts from important potential source areas that should be filled in the future the here compiled data set can be used as a reference frame when incorporating the composition of source sediments e g mineralogy into global or regional dust transport models and can be compared with source analysis by remote sensing or back trajectory analysis however source apportionment studies supported by our data set will not only be useful for actual dust samples but will also be helpful for the understanding of paleo wind directions and hence paleo climatological conditions through the investigation of quaternary eolian sediments deposited in and around northern africa

stratigraphy depositional environments and level reconstruction of the last interglacial lake samra in the dead sea basin in this paper we describe the stratigraphy and sediments deposited in lake samra that occupied the dead sea basin between 135 and 75 ka this information is combined with u th dating of primary aragonites in order to estimate a relative lake level curve that serves as a regional paleohydrological monitor the lake stood at an elevation of 340 m below mean sea level msl during most of the last interglacial this level is relatively higher than the average holocene dead sea 400 30 m below msl at 120 and 85 ka lake samra rose to 320 m below msl while it dropped to levels lower than 380 m below msl at 135 and 75 ka reflecting arid conditions in the drainage area lowstands are correlated with warm intervals in the northern hemisphere while minor lake rises are probably related to cold episodes during mis 5b and mis 5d similar climate relationships are documented for the last glacial highstand lake lisan and the lowstand holocene dead sea yet the dominance of detrital calcites and precipitation of travertines in the dead sea basin during the last interglacial interval suggest intense pluvial conditions and possible contribution of southern sources of wetness to the region

u series and oxygen isotope chronology of the mid pleistocene lake amora dead sea basin abstract this study establishes for the first time the chronology and limnological history of lake amora dead sea basin israel whose deposits the amora formation comprise one of the longest exposed lacustrine records of the pleistocene time the amora formation consists of sequences of laminated primary aragonite and silty detritus ca sulfate minerals halite and clastic units this sedimentary sequence was uplifted and tilted by the rising sedom salt diapir exposing 320 m of sediments on the eastern flanks of mt sedom the arubotaim cave ac section the chronology of the ac section is based on u disequilibrium dating 230th 234u and 234u 238u ages combined with floating 18 o stratigraphy and paleomagnetic constraints the determination of the 230th 234u ages required significant corrections to account for detrital th and u these corrections were performed on individual samples and on suites of samples from several stratigraphic horizons the most reliable corrected ages were used to construct an age elevation model that was further tuned to the oxygen isotope record of east mediterranean foraminifers based on the long term similarity between the sea and lake oxygen isotope archives the combined u series 18 o age elevation model indicates that the exposed amora sequence was deposited between 740 and 70 ka covering seven glacial interglacial cycles marine isotope stages mis 18 to 5 taking the last glacial lake lisan and the holocene dead sea lacustrine systems as analogs of the depositional limnological environment of lake amora the latter oscillated between wet glacial and more arid interglacial conditions represented by sequences of primary evaporites aragonite and gypsum that require enhanced supply of freshwater to the lakes and clastic sediments respectively the lake evolved from a stage of rapid shifts between high and low stand conditions during 740 to 550 ka to a sabkha like environment that existed at the ac site between 550 and 420 ka this stage was terminated by a dry spell represented by massive halite deposition at 420 ka mis12 11 during mis10 6 the lake fluctuated between lower and higher stands reaching its highest stand conditions at the late glacial mis6 after which a significant lake level decline corresponds to the transition to the last interglacial mis5 low stand lake represented by the uppermost part of the formation 18 o values in the primary aragonite range between 6 0 and 1 3 shifting cyclically between glacial and interglacial intervals the lowest 18 o values are observed during interglacial stages and may reflect short and intense humid episodes that intermittently interrupted the overall arid conditions these humid episodes expressed also by enhanced deposition of travertines and speleothems seem to characterize the negev desert and in contrast to the overall dominance of the atlantic mediterranean system of rain patterns in the dead sea basin some humid episodes during interglacials may be traced to southern sources

sea land oxygen isotopic relationships from planktonic foraminifera and speleothems in the eastern mediterranean region and their implication for paleorainfall during interglacial intervals the oxygen and carbon stable isotope compositions of cave speleothems provide a powerful method for understanding continental climate change here we examine the question of the regionality of this isotopic record and its linkage with the marine isotopic record in the eastern mediterranean em region the study presents a new accurately dated 250 kyr 18o and 13c record determined from speleothems of the peqiin cave northern israel its comparison with the continuous 185 kyr isotopic record of the soreq cave speleothems from central israel reveals striking similarities thus a strong regional climatic signal brought about by variations in temperature and rainfall amount is reflected in both cave records low 18o minima in the peqiin profile for the last 250 to 185 kyr period interglacial marine isotopic stage 7 match the timing of sapropels 9 to 7 and are indicative of high rainfall in the em region at these times the combined soreq and peqiin 18o record for the last 250 kyr excellently matches the published globigerinoides ruber g ruber marine 18o record for the em sea with the isotopic compositional difference g ruber speleothems remaining relatively constant at 5 6 0 7 thus establishing for the first time a robust exploitable link between the land and the marine isotopic records the correspondence of low 18o speleothem values and high cave water stands with low g ruber 18o values during interglacial sapropel events indicates that these periods were characterized by enhanced rainfall in the em land and sea regions by use of sea surface temperatures derived from alkenone data as a proxy for land temperatures at the soreq cave we calculate the paleorainfall 18o values and its amounts maximum rainfall and lowest temperature conditions occurred at the beginning of the sapropel events and were followed by decrease in rainfall and increase in temperatures leading to arid conditions the record for the last 7000 yr shows a trend toward increasing aridity and agrees well with climatic and archeological data from north africa and the middle east

catastrophic arid episodes in the eastern mediterranean linked with the north atlantic heinrich events the response of continental climate to the well documented climate oscillations during the last glacial period has been a subject of intense interest yet much less is known about the influence on regional continental climates than in the marine or polar realms of earth the detailed lake level history of the closed lake lisan paleo dead sea in the middle east has been reconstructed from shoreline indications and high resolution u th and 1 4 c chronologies thus providing data on the response of the lake s catchment area to the climate changes during the corresponding period we present a correlation between the newly developed lake lisan level curve for the past 55 k y and the north atlantic heinrich events the correlation indicates a closely connected climate response between these north atlantic events and the hydrologic conditions that prevailed in the eastern mediterranean our findings show that although the generally cooler conditions that prevailed during the last glaciation favored high levels of the lake catastrophic events in the north atlantic which are associated with maximum cooling have been responsible for droughts in the eastern mediterranean we infer that cold water input to the mediterranean originating in the collapse of the north atlantic deep water circulation caused the reduction of evaporation and less precipitation in the eastern mediterranean

mount sedom salt diapir source for sulfate replenishment and gypsum supersaturation in the last glacial dead sea lake lisan abstract during the late quaternary several hypersaline lakes occupied the tectonic depression of the dead sea basin depositing sequences of primary evaporitic mineral phases aragonite caco3 gypsum caso4 2h2o and halite nacl aragonite and gypsum were the dominant primary mineral phases during the glacial periods and their formation required significant import of bicarbonate hco3 and sulfate so42 ions to the lake while bicarbonate was likely derived from dissolution of calcite in the watershed the sources of sulfate remained elusive here we investigate and quantify the long term sulfate reservoir changes in the deep waters hypolimnion of lake lisan the last glacial dead sea using concentrations and stable isotopes of sulfur in pore fluids from the cores that were drilled at the lake floor 2010 11 by icdp international continental drilling program from ca 117ka pore fluid sulfate concentrations increased and the brine attained supersaturation with respect to gypsum peaking during the last glacial maximum lgm ca 20ka stable isotopes of pore fluid sulfate 34s and 18o are similar to the values found in bulk sulfate minerals from the nearby mount sedom salt diapir we suggest that relatively diluted and cool paleo epilimnion water facilitated dissolution of halite and anhydrite caso4 of the mt sedom salt diapir resulting in a localized increase in solution density subsequently this solution sank and mixed with saline hypolimnion water simultaneously replenishing chloride sodium and sulfate reservoirs while diluting it with respect to other solutes the mixing of the calcium rich gypsum saturated hypolimnion and the sulfate rich sinking brine from above resulted in gypsum supersaturation

impacts of abrupt climate changes in the levant from last glacial dead sea levels abstract a new detailed lake level curve for lake lisan the last glacial dead sea reveals a high frequency of abrupt fluctuations during marine isotope stage 3 mis3 compared to the relatively high stand characterizing mis2 and the significantly lower holocene lake the lake level fluctuations reflect the hydrological conditions in the large watershed of the lake which in turn reflects the hydro climatic conditions in the central levant region the new curve shows that the fluctuations coincide on millennial timescales with temperature variations recorded in greenland four patterns of correlation are observed through the last ice age 1 maximum lake elevations were reached during mis2 the coldest interval 2 abrupt lake level drops to the lowest elevations coincided with the occurrence of heinrich h events 3 the lake returned to higher stand conditions along with warming in greenland that followed h events 4 significant lake level fluctuations coincided with virtually every greenland stadial interstadial cycle over glacial interglacial time scales northern hemisphere glacial cooling induces extreme wetness in the levant with high lake levels reaching 160 m below mean sea level mbmsl approximately 240 m above typical holocene levels of 400 mbmsl these orbital time scale shifts are driven by expansions of the european ice sheet which deflect westerly storm tracks southward to the eastern mediterranean resulting in increased sea air temperature gradients that invoke increased cyclogenesis and enhanced moisture delivery to the levant the millennial scale lake level drops associated with greenland stadials are most extreme during heinrich stadials and reflect abrupt cooling of the eastern mediterranean atmosphere and sea surface which weaken the cyclogenic rain engine and cause extreme levant droughts during the recovery from the effect of heinrich stadials the regional climate configuration resumed typical glacial conditions with enhanced levant precipitation and a rise in lake lisan levels similar cyclicity in the transfer of moisture to the levant affected lake levels during all of the non heinrich stadial interstadial cycles

late holocene lake levels of the dead sea this work presents a high resolution lake level record of the late holocene dead sea a hypersaline terminal lake whose drainage basin encompasses both mediterranean and hyperarid climatic zones the lake level curve reflects the regional hydrologic variations in the drainage basin which in turn represent the levant paleoclimates the curve is based on 46 radiocarbon ages of organic remains from well exposed sedimentary sequences along the dead sea shores these sequences record fluvial and lacustrine depositional environments the paleolakeshores are marked by shore ridges coarse sand units and aragonite crusts in the modern dead sea such features indicate the exact elevation of the shore the late holocene dead sea level fluctuated within the range of 390 to 415 m below sea level mbsl for most of the time the lake was below the topographic sill 402 mbsl separating the northern and southern basins of the dead sea and was confined to the deep northern basin nevertheless short term rises in the late holocene dead sea level caused the flooding of the shallow and flat southern basin highstands occurred in the second and first centuries b c and the fourth century a d during the roman and early byzan tine periods respectively in the eleventh and twelfth centuries a d during the crusader period and at the end of the nineteenth century a d the rises mark a significant change in the annual rainfall in the region which likely exceeded the instrumentally measured modern average the curve also indicates drastic drops that exposed the sedimentary sequences to erosion the oldest and probably deepest drop in the lake level culminated during the fifteenth and fourteenth centuries b c after a retreat from a higher lake stand the longest lowstand occurred after the byzantine period and continued at least until the ninth century a d this arid period coincided with the invasion of moslem arab tribes into the area during the seventh century a d the dramatic fall of the dead sea level during the twentieth century is primarily artificial and has been caused by the diversion of runoff water for the drainage basin but the magnitude is not considered exceptional for the late holocene although the past drops in the lake never exceeded the modern artificial drop rates they do represent extreme arid conditions that occurred frequently over the past several thousand years

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

ground based detection of sprites and their parent lightning flashes over africa during the 2006 amma campaign sprites have been detected in video camera observations from niger over mesoscale convective systems in nigeria during the 2006 amma african monsoon multidisciplinary analysis campaign the parent lightning flashes have been detected by multiple extremely low frequency elf receiving stations worldwide the recorded charge moments of the parent lightning flashes are often in excellent agreement between different receiving sites and are furthermore consistent with conventional dielectric breakdown in the mesosphere as the origin of the sprites analysis of the polarization of the horizontal magnetic field at the distant receivers provides evidence that the departure from linear magnetic polarization at elf is caused primarily by the day night asymmetry of the earth ionosphere cavity copyright c 2009 royal meteorological society

sprite observations in the northern territory of australia sprites a form of brief luminous discharge in the upper atmosphere above a thunderstorm were observed and imaged on two video cameras in australia s northern territory these were the first such ground based observations made outside the united states sprite discharges typically took place between the altitudes of 50 km and 80 km and spanned an average width of 44 km many of the sprite events were of long duration with an average of 145 ms these spatial and temporal features were similar to those observed from the ground and the air in the united states during the longer events some luminous discharge elements were observed to decay as other new elements formed as the new elements were often laterally displaced from the old the sprites sometimes appeared to dance across the sky this phenomenon has been observed in colorado and named dancing sprites the lateral progression of sprite elements observed in the northern territory was overwhelmingly in one direction and covered distances of up to 90 km

lithology of the long sediment record recovered by the icdp dead sea deep drilling project dsddp abstract the sedimentary sections that were deposited from the holocene dead sea and its pleistocene precursors are excellent archives of the climatic environmental and seismic history of the levant region yet most of the previous work has been carried out on sequences of lacustrine sediments exposed at the margins of the present day dead sea which were deposited only when the lake surface level rose above these terraces e g during the last glacial period and typically are discontinuous due to major lake level variations in the past continuous sedimentation can only be expected in the deepest part of the basin and therefore a deep drilling has been accomplished in the northern basin of the dead sea during winter of 2010 2011 within the dead sea deep drilling project dsddp in the framework of the icdp program approximately 720 m of sediment cores have been retrieved from two deep and several short boreholes the longest profile 5017 1 revealed at a water depth of 300 m reaches 455 m below the lake floor blf i e to 1175 m below global mean sea level and comprises approximately the last 220 240 ka the record covers the upper part of the amora penultimate glacial the last interglacial samra the last glacial lisan and the holocene ze elim formations and therewith two entire glacial interglacial cycles thereby for the first time consecutive sediments deposited during the mis 6 5 5 4 and 2 1 transitions were recovered from the dead sea basin which are not represented in sediments outcropping on the present day lake shores in this paper we present essential lithological data including continuous magnetic susceptibility and geochemical scanning data and the basic stratigraphy including first chronological data of the long profile 5017 1 from the deep basin the results presented here a focus on the correlation of the deep basin deposits with main on shore stratigraphic units thus providing a unique comprehensive stratigraphic framework for regional paleoenvironmental reconstruction and b highlight the outstanding potential of the dead sea deep sedimentary archive to record hydrological changes during interglacial glacial and transitional intervals

the evolution of a severe mesoscale convective system cloud to ground lightning location and storm structure abstract cloud to ground lightning location data are correlated with the doppler radar observed structure of the evolution of a severe mesoscale convective system in oklahoma on 23 may 1981 while many of the results are not new this study is unique in that the evolution of electrical activity in a severe storm is compared to storm structure for most of the storm s life the first storm formed ahead of a mesoscale low pressure area located at the intersection of a front and a dryline and developed into a tornadic supercell in an environment of locally enhanced vertical shear ordinary cells subsequently formed both to the southwest and northeast of the supercell along the dryline and the front respectively and merged with the supercell to form a squall line having a trailing stratiform precipitation region with midlevel rear inflow it is shown that the cloud to ground flash rate in the convective region is related to the apparent strength of the updraft before the storm became a supercell the ligh

the sahara east mediterranean dust and climate connection revealed by strontium and uranium isotopes in a jerusalem speleothem this paper explores the potential of sr and u isotope systems in speleothems as tracers of eolian dust transport and hydrological conditions the study focuses on a speleothem from jerusalem spanning the past 220 kyr this speleothem provides a precisely dated record of dust flux from the sahara to the east mediterranean enhanced dust flux and terra rossa soil development are reflected by elevated 87sr 86sr ratios in the speleothem 0 7082 0 7086 while lower 87sr 86sr ratios 0 7078 indicate higher contribution of the local bedrock due to low dust flux and low soil accumulation the strontium isotope system in the speleothem is a robust monitor of the sahara monsoon modulated climate since dust uptake is related to development or reduction in vegetation cover of sahara soil the 234u 238u activity ratios in the speleothem range between 1 12 and 1 0 the high activity values may indicate selective removal of 234u from the soil while the low values converge to the bedrock the migration of 234u to the cave reflects mainly the regional hydrological conditions that are modulated by the north atlantic mediterranean climate system thus the speleothem provides a combined record of the monsoon north atlantic climatic systems long term stability in glacial 87sr 86sr ratios 0 7083 0 0001 over the past 220 kyr suggests an overall similarity in eolian dust sources and uniformity in the synoptic conditions that dominate the dust storm tracks during glacial periods

a 45 kyr laminae record from the dead sea implications for basin erosion and floods recurrence abstract recording and analyzing how climate change impacts flood recurrence basin erosion and sedimentation can improve our understanding of these systems the aragonite detritus laminae couplets comprising the lacustrine formations that were deposited in the dead sea are considered as faithful monitors of the freshwater supply to the lakes we count a total of 5600 laminae couplets deposited in the last 45 kyr mis3 mis1 at the dead sea center which encompass the upper 142 m of the icdp core 5017 1 the present study shows that aragonite and detritus laminae are thinner and occur at high frequency during mis 3 2 while they are much thicker and less frequent during mis 1 by analyzing multiple climate connected factors we propose that significant lake level drops enhanced dust input and low vegetative cover in the drainage basin during the last deglaciation 22 11 6 ka have considerably increased erodible materials in the dead sea watershed we find a decoupling existed between the significant lake level drop lake size reduction and lamina thickness change during the last deglaciation we argue that during the last glacial and the holocene the variation of lamina thickness at the multiple millennium scale was not controlled directly by the lake level size change we interpret this decoupling implying the transport capacity of flash floods is low and might be saturated by the oversupply of erodible materials and indicating a transport limited regime during the time period we suggest the observed thickness and frequency distribution of aragonite detritus laminae points to the high frequency of small magnitude floods during the last glacial in contrast to low frequency but large magnitude floods during the holocene

triangulation of sprites associated halos and their possible relation to causative lightning and micrometeors sprite halos were recently identified as an impulsive but spatially diffuse phenomenon that sometimes occurs just prior to but distinct from sprites the lack of discernible spatial structure and the temporal development sequence in halos differs markedly from the highly structured bodies and tendrils and the complex development sequences of sprites however both phenomena are thought to result from an electric field due to charge moment changes usually associated with large positive cloud to ground cg lightning but also following negative cg flashes three dimensional triangulations of sprites and sprite halos were made between stations in south dakota and wyoming in august 1999 during the nasa sprites99 balloon campaign halos were found to have a gaussian 1 e diameter of 66 km and 1 e thickness of 4 km comparison with the location of the underlying lightning strokes as recorded by the national lightning detection network nldn confirms that the horizontal position of sprites may be laterally offset by as much as 50 km from the underlying parent lightning discharge as has been previously reported the point of maximum apparent brightness for sprite halos occurs at an altitude of 78 km similar to that of sprites however unlike sprites this point tends to be centered directly above the underlying parent lightning discharge 4 6 2 7 km mean distance from the center of the halo to the nldn location this difference in spatial location relative to the underlying lightning suggests that the electrical breakdown associated with discrete sprites may require a random ionizing event such as a micrometeor in contrast sprite halos do not appear to require such a random component

sprite initiation altitude measured by triangulation 1 high time resolution 10 000 frames per second images of sprites combined with multistation concurrent video recordings have provided data for triangulation of the altitude of the initial sprite onset the high speed images were obtained from the langmuir laboratory new mexico during summer campaigns in 2007 and 2008 with video observations from sites at portales new mexico and las vegas new mexico sprites start with one or more downward propagating streamer heads the triangulated onset altitudes of this initial downward streamer vary between 66 and 89 km in some sprites the downward streamers are followed a little later by upward propagating streamers the upward streamers start from a lower altitude and existing luminous sprite structures and their triangulated altitudes vary from 64 to 78 km the downward streamers create c sprite characteristics while the upward streamers form the broad diffuse tops of carrot sprites in the sprites analyzed the higher onset altitudes for the downward propagating initial streamers were associated with c sprites and the lower with carrot sprites but our larger data set indicates that this is not generally the case it appears that the dominant sprite types vary from year to year indicating that some longer lasting environmental parameter such as mesospheric conductivity and composition or thunderstorm cloud dynamics may play an important role in determining the types of sprites observed

horizontal structure of the electric field in the stratiform region of an oklahoma mesoscale convective system 1 this analysis combines vertical electric field components ez observed by two research aircraft flying horizontally at two levels with vertical soundings of thermodynamic parameters and ez made by five balloons to produce a quasi three dimensional view of the space charge distribution in the trailing stratiform cloud region behind a mesoscale convective system mcs that developed in central oklahoma late in the afternoon of 2 june 1991 the balloons were launched serially at one hour intervals from two sites separated by 80 km along a north south line as the mcs moved eastward yielding two east west time height cross sections of the ez structure within the quasi steady state trailing stratiform region behind the mcs the balloon measurements are consistent with a vertical stack of five rearward and downward sloping horizontal sheets of charge of alternating polarity beginning at the bottom with a negative charge layer below the 0 c level and a positive layer near the 0 c level this structure persisted for more than 2 hours the two aircraft flew back and forth along a north south line through the balloon launch sites during the balloon launch period aircraft measurements demonstrated that the vertical electric field ez at constant altitude varied in the north south direction the peak magnitudes of ez deduced from the airborne instrument systems agreed with the magnitudes deduced from the balloon measurements at the aircraft altitudes of 4 5 km and 5 8 km agl rapid reversals in polarity of ez with peak magnitude 50 kv m 1 observed by the aircraft at 4 5 km just above the 0 c level confirms the thin concentrated positive charge layer observed there by balloons and suggests that this charge layer is undulating above and below 4 5 km altitude at least in the north south direction microphysically this layer contained large aggregates and pockets of low cloud liquid water concentration at the 5 8 km level the polarity of ez was always positive but the magnitude varied from zero to 25 kv m 1 aircraft observed ez at both altitudes varied on horizontal scales of 10 km or greater at both levels suggesting that the charge density derived using the one dimensional infinite layer gauss s law approximation applied to the balloon soundings of ez is valid in this study these observations show that layers of charge can persist for hours as they advect rearward in a storm relative sense possibly due to continuing in situ charge separation and or due to weak dispersion slow recombination and slow settling of charge attached to low mobility low terminal velocity ice hydrometeors

holocene sea level determination relative to the australian continent u th tims and 14c ams dating of coral cores from the abrolhos islands u th tims and 14 c ams measurements are presented from two coral cores from the easter group of the houtman abrolhos islands between 28 s and 29 s on the western continental margin of australia the u th measurements on the morley core from morley island cover a depth interval from 0 2 m above present sea level to 24 4 m below present sea level and comprise eleven samples the ages vary between 6320 50 a at 0 2 m above sea level and 9809 95 a at 24 4 m below sea level all errors are 2 the mean growth rate is 7 1 0 9 m ka the 14 c dates of selected morley core corals show that the 14 c ages are 1000 a younger than their corresponding u th ages which agrees with previous results the main purpose of our 14 c measurements is to be able to compare them precisely with other coral cores where no u th measurements are available the u th measurements of the suomi core from suomi island cover a depth interval from 0 05 m to 14 2 m below present sea level and consist of four samples the ages vary between 4671 40 a at 0 05 m below sea level and 7102 82 a at 14 2 m below sea level with a mean growth rate of 5 8 0 2 m ka the growth history of both cores is explained by a simple model in which the growth rates of the morley core can be interpreted as reflecting local rates of sea level rise whereas the suomi core is interpreted as reflecting lateral growth during the past 6000 a our results indicate that sea level relative to the western margins of the australian continent was about 24 m lower than present at about 9800 a b p 14 c gives a date of 8500 a b p sea level then rose and reached a highstand slightly higher than the present position at about 6300 a b p 14c date 5500 a this highstand declined but was still higher than present at 4600 a b p this is in agreement with previous observations along the australian coastal margins and with observations from the huon peninsula papua new guinea our results are very similar to theoretical numerical models which take into consideration water loading and isostatic compensation and viscous mantle flow in contrast coral cores from barbados show that corals with a 14 c age of 5500 a b p are some 10 m b p s l we interpret the difference between the barbados core and the morley core as resulting from additional flooding of barbados by water redistribution due to changes in the earth s geoid but not reflecting global sea level rise or major addition of melt waters over the past 6000 a the difference in the geoid at barbados between 6000 a b p and the present will require a refinement in the geophysical models precise 230 th tims measurements on continental coasts will be required to provide an adequate data base for modelling deformation flow of mantle material and sea level height

aggradation incision transition in arid environments at the end of the pleistocene an example from the negev highlands southern israel abstract one of the most significant environmental processes that occurred at the transition from the last glacial phase into the present inter glacial phase in arid regions was the shift from aggradation to incision in the drainage systems this is evident by the sharp transition from a fluvial regime depositing fine grained sediment within the wadis to intensive incision which formed gullies and narrow channels that dissected the late pleistocene sediments in order to investigate this transition we studied three small scale basins in the arid region of the negev highlands southern israel although the selected basins drain toward different base levels their geomorphological parameters particle size distribution of alluvial units and their osl ages are similar sediments from the penultimate glacial cycle are found in patches in the bigger catchments fluvial loess was widely deposited since at least 67 ka until after 28 ka covering valleys and slopes between 28 and 24 ka loess was washed from the slopes into the channels exposing the underlying colluvium at 24 ka erosion began with the transport of slope colluvium as gravels into the valleys that eroded the underlying loess sediments incision became dominant at 12 ka and is still ongoing and intensifying dust and reworked loess continued to be deposited during the main incision stages it is proposed that the transition from aggradation to incision was controlled by rates of loess supply and removal until 24 ka dust choked the drainage system and only after reduction in dust supply was erosion and incision possible it began first on the slopes and then in the channels our results show that an increase in precipitation is not a prerequisite for initiation of incision as is often assumed similar processes are described in other arid zones around the world

significance of primary hilltop loess in reconstructing dust chronology accretion rates and sources an example from the negev desert israel 1 although high latitude loess sequences have been studied extensively for reconstructing past climates loess in desert margins has been mostly overlooked moreover many low latitude loess studies have focused on secondary reworked sequences for which paleoclimatic inferences are complicated owing to postdepositional processes acting under local control in this respect the spatial distribution of the loess and its different types are crucial in this study we differentiate primary and secondary loess using remote sensing and field criteria we present remote sensing and geographic information system procedures for mapping loess distribution in general and for identifying pristine hilltop loess sequences in particular then we present the mineralogical and textural analyses combined with optically stimulated luminescence ages of one such primary hilltop loess sequence in the negev desert that show that the late pleistocene negev loess started accumulating at 95 ka much earlier than previously proposed 70 ka it was preceded by a previously unknown middle pleistocene period of loess formation at 180 130 ka the ages also suggest that the threshold of dust accretion rate needed for loess formation is 0 02 mm a 1 30 g m 2 a 1 a factor of 2 or more lower than previously thought 0 04 to 1 0 mm a 1 our results also provide insights into causes of late pleistocene loess accretion and its close association with regional dune field activity the methodology for mapping the loess distribution may potentially be generalized to help understanding loess formation in other more remote desert areas

dead sea drawdown and monsoonal impacts in the levant during the last interglacial sediment cores recovered by the dead sea deep drilling project dsddp from the deepest basin of the hypersaline terminal dead sea lake floor at 725 m below mean sea level reveal the detailed climate history of the lake s watershed during the last interglacial period marine isotope stage 5 mis5 the results document both a more intense aridity during mis5 than during the holocene and the moderating impacts derived from the intense mis5e african monsoon early mis5e 133 128 ka was dominated by hyperarid conditions in the eastern mediterranean levant indicated by thick halite deposition triggered by a lake level drop halite deposition was interrupted however during the mis5e peak 128 122 ka by sequences of flood deposits which are coeval with the timing of the intense precession forced african monsoon that generated mediterranean sapropel s5 a subsequent weakening of this humidity source triggered extreme aridity in the dead sea watershed and resulting in the biggest known lake level drawdown in its history reflected by the deposition of thick salt layers and a capping pebble layer corresponding to a hiatus at 116 110 ka the dsddp core provides the first evidence for a direct association of the african monsoon with mid subtropical latitude climate systems effecting the dead sea watershed combined with coeval deposition of arabia and southern negev speleothems arava travertines and calcification of red sea corals the evidence points to a climatically wet corridor that could have facilitated homo sapiens migration out of africa during the mis5e peak the hyperaridity documented during mis5e may provide an important analogue for future warming of arid regions of the eastern mediterranean levant

the late quaternary limnological history of lake kinneret sea of galilee israel the freshwater lake kinneret sea of galilee and the hypersaline dead sea are remnant lakes evolved from ancient water bodies that filled the tectonic depressions along the dead sea transform dst during the neogene quartenary periods we reconstructed the limnological history level and composition of lake kinneret during the past 40 000 years and compared it with the history of the contemporaneous lake lisan from the aspect of the regional and global climate history the lake level reconstruction was achieved through a chronological and sedimentological investigation of exposed sedimentary sections in the kinnarot basin trenches and cores drilled at the ohalo ii archeological site shoreline chronology was established by radiocarbon dating of organic remains and of melanopsis shells the major changes in lake kinneret level were synchronous with those of the southern lake lisan both lakes dropped significantly 42 000 30 000 23 800 and 13 000 yr ago and rose 39 000 26 000 5000 and 1600 yr ago between 26 000 and 24 000 yr ago the lakes merged into a unified water body and lake level achieved its maximum stand of 170 m below mean sea level m bsl nevertheless the fresh and saline water properties of lake kinneret and lake lisan respectively have been preserved throughout the 40 000 years studied calcium carbonate was always deposited as calcite in lake kinneret and as aragonite in lake lisan dead sea indicating that the dead sea brine which supports aragonite production never reached or affected lake kinneret even during the period of lake high stand and convergence the synchronous level fluctuation of lakes kinneret lisan and the holocene dead sea is consistent with the dominance of the atlantic mediterranean rain system on the catchment of the basin and the regional hydrology the major drops in lake kinneret lisan levels coincide with the timing of cold spells in the north atlantic that caused a shut down of rains in the east mediterranean and the lakes drainage area d 2004 university of washington all rights reserved

evidence from lake lisan of solar influence on decadal to centennial scale climate variability during marine oxygen isotope stage 2 documentation of short term climate variability during the glacial period has been limited by the availability of well dated high resolution archives here we present a paleoclimate reconstruction from varved lacustrine sediments of lake lisan dead sea rift for ca 26 2 17 7 calendar ka the age is based on a floating varve chronology anchored to radiometric dates our reconstruction indicates that small ice rafting events a b c and d as well as heinrich events in the north atlantic are associated with the eastern mediterranean arid intervals study of seasonal sublaminae yields evidence of several additional decadal to century scale arid events that correlate with cooler temperatures at higher latitudes analyses in the frequency domain indicate the presence of periodicities centered at 1500 yr 500 yr 192 yr 139 yr 90 yr and 50 60 yr suggesting a solar forcing on climate

the climate variability in northern levant over the past 20 000 years the levant constitutes an important region for assessing linkages between climate and societal changes throughout the course of human history however large uncertainties remain in our understanding of the region s hydroclimate variability under varying boundary conditions here we present a new high resolution precisely dated speleothem oxygen carbon isotope and sr ca records spanning the last 20 ka from jeita cave northern levant our record reveals a higher lower precipitation evaporation p e balance during the last glacial maximum and bolling interstadial heinrich stadial 1 the early middle holocene is characterized by a trend toward higher p e state culminating between similar to 7 and 6 ka the middle late holocene is characterized by two millennial length drier periods during 5 3 4 2 and 2 8 1 4 ka on submillennial time scale the northern levant climate variability is dominated by 500 year periodicity comparisons with the regional proxy records suggest persistent out of phase climate variability between the northern and southern levant on a wide range of timescales

revised chronology of the icdp dead sea deep drill core relates drier wetter drier climate cycles to insolation over the past 220 kyr abstract the dead sea deep drilling project drilled 456 meters into the deepest floor of the dead sea and recovered a record of the past 220 kyr of the levant hydroclimate history that is marine isotope stages 1 7 including the last three interglacials and the last two glacials we present an updated chronology of the core from dsddp hole 5017 1 a from the dead sea s deepest basin that refines our previous chronology torfstein et al 2015 based on new information the updated chronology uses the following approaches 1 radiocarbon ages of kitagawa et al 2017 2 correlation of specific layers in the core with u th dated sediments on the dead sea margin particularly during the interval of glacial lake lisan mis 2 3 4 3 tuning of the 18o data of dsddp core aragonite to the u th dated oxygen isotopes of regional cave speleothems and 4 tuning of the dsddp aragonite 18o data to summer insolation curves when the cave 18o chronology is less clear the updated chronology reveals a strong relationship between the sedimentary facies comprising the core and northern hemisphere summer insolation variations it shows that sequences of sediments marking drier wetter drier climate conditions in the lake s watershed e g salt muds salt respectively appear across the flank peak flank segments of several summer insolation peaks in particular the transition from drier to wetter sedimentary facies during mid latitude insolation peaks coincides with the intervals of sapropel conditions in the mediterranean reflecting enhanced nile flow due to intense african monsoonal conditions and marking the impact of the tropical precession cycles on eastern mediterranean hydroclimate this pattern was lost during mis 2 3 4 when mostly sequences of primary aragonite are punctuated by gypsum precipitation during heinrich events marking the strong impact of the north atlantic on the last glacial levant hydroclimate

an unusual sequence of sprites followed by a secondary tle an analysis of elf radio measurements and optical observations we present an extraordinary case of sprites in rapid succession four sprite clusters in only 400 ms followed by a secondary jet simultaneous elf and optical observations as well as lightning data enabled us to thoroughly document this unique event locations of the transient luminous events tles were triangulated using video recordings from nydek czech republic and sopron hungary we found that sprites were displaced up to 70 km from their parent lightning the current moment waveform and charge moment changes associated with the event were reconstructed from the elf electromagnetic signature recorded at the hylaty station poland by a new method the results suggest that both a short delayed and a long delayed sprite were generated by a single positive cloud to ground discharge that had an intense continuing current it had an unusual progression and lasted 200 ms a large increase in the current moment during the development of a massive carrot sprite provides evidence in favor of sprite current our results also support the formation of an electric environment hypothesized to be necessary for the generation of the secondary tles

the modern and last glacial maximum hydrological cycles of the eastern mediterranean and the levant from a water isotope perspective abstract the isotopic composition of precipitation p is one of the most widely used and informative terrestrial paleoclimate proxies p integrates a series of hydrological processes therefore any interpretation of paleohydrology using p requires a thorough understanding and quantification of the full hydrological cycle in this paper we use modern data to analytically model the full isotopic hydrological cycle of the eastern mediterranean and the southern levant including oceanic evaporation distillation during transport and precipitation over land this model allows us to determine the important factors controlling this system the model results underscore the significance of the isotopic distillation process driven by the land sea temperature gradient as a significant factor controlling the long term average isotopic composition of precipitation across israel based on the understanding of the processes that govern the modern system we model the isotopic composition of precipitation from the last glacial maximum lgm using published data for speleothem oxygen isotopes in calcite oxygen and hydrogen isotopes in fluid inclusions and clumped isotope values from soreq cave and the isotopic composition of east mediterranean planktonic foraminifera g ruber the data and model results indicate two plausible scenarios for the lgm that entail changes in the magnitude of distillation over israel in normalized humidity over the mediterranean and possible shifts of the moisture trajectories over the mediterranean the results presented in the paper illustrate the importance of understanding the full local hydrological cycle when reconstructing and interpreting the isotopic composition of precipitation

controlling factors on a paleo lake oxygen isotope record yammouneh lebanon since the last glacial maximum abstract late quaternary paleoclimatic changes in the levant are difficult to extract from carbonate oxygen isotope records partly because the factors controlling the terrestrial 18 o signals are not fully understood in this region characterized by sharp climatic gradients here we address this purpose by presenting the first 14 c dated isotope record from the northern levant the record is based on oxygen isotopes from ostracod shells from lacustrine palustrine deposits accumulated in a small karstic hydrologically open basin yammouneh located on the eastern flank of mount lebanon we have first constructed a composite isotopic record obtained from three different ostracod taxa this yields an oxygen isotope record of ostracods ost related to the most widespread species ilyocypris inermis and converted to 18 o values coeval with calcite precipitated in equilibrium c with the lake water l as with other records from the mediterranean region the yammouneh profile shows maximum and minimum c values during the lgm and the early holocene respectively and a slight late holocene increase in order to discuss the potential causes of the observed 18 o values fluctuations e g changes in the isotopic composition of the moisture source temperature precipitation minus evaporation p e balance or atmospheric circulation we tentatively reconstruct the lake water isotope composition by correcting the c values for lake water temperature using regional paleotemperature estimates inferred l values were then corrected for the isotopic composition of the eastern mediterranean sea surface water the moisture source derived from planktonic foraminifera 18 o values corrected for alkenone based sea surface temperature our study suggests that holocene l fluctuations are primarily linked to changes in the sea surface water composition source effect amplified by enhanced inland rainfall during the early holocene during the lgm low l values at yammouneh are likely due to the ground temperature effect on the rainfall isotope composition possibly associated with a steeper altitudinal thermal gradient inland and with changes in air mass trajectories over the mediterranean sea

rock varnish evidence for a younger dryas wet period in the dead sea basin 1 rock varnish from 14 6 to 13 2 ka recessional shorelines of late glacial lake lisan and fan delta surfaces between 280 and 365 m bmsl meters below mean sea level along the western margins of the dead sea contains replicable layering patterns characterized by a low mn and ba orange yellow surface layer and a high mn and ba dark basal layer the deposition of the dark basal layers immediately after the lake recession represents a wet period coinciding with the younger dryas yd cooling 12 9 11 6 ka manifesting the influence of midlatitude westerly winds in the eastern mediterranean central levant em cl in contrast varnish from the distal base of fan deltas contains only orange yellow surface layers diagnostic of the holocene relatively dry climate the absence of the dark basal layers in the varnish further indicates a yd high stand at 365 m bmsl and a lake level rise of at least 100 m from its bolling allerod lowstand this rise stands in contrast to the abrupt drop of the lake level during the heinrich h1 cold event illustrating the opposite response of the em cl climate to changes in the north atlantic climate the yd wet event most likely reflects a southward shift of the atlantic meridional overturning circulation modulated midlatitude westerly wind belt in the em cl region

implications of lightning charge moment changes for sprite initiation 1 we report impulse lightning charge moment changes defined as occurring in the first 2 ms after return stroke onset in all cloud to ground lightning strokes detected by the national lightning detection network in three storms during which above thunderstorm sprite video was recorded after analyzing strokes that both did and did not produce sprites and carefully accounting for lightning sprite delay times we found that sprite initiation on all three nights is consistent with a sharp charge moment threshold essentially all charge moment changes above and none below this threshold produced sprites with short delays 5 ms from the source lightning on two nights this threshold was approximately 600 c km and on the other it was approximately 350 c km this internight variability is probably due to expected variability in the nighttime mesospheric conductivity and the thresholds themselves are consistent with predictions of conventional breakdown theory additionally we found only one negative polarity lightning stroke from all three storms that exceeded this threshold indicating that the rarity of documented sprites produced by negative strokes may be largely explained by the lack of sufficiently big negative strokes in the u s high plains

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

the holocene climatic optimum and pollen records of sapropel 1 in the eastern mediterranean 9000 6000 bp abstract the most recent sapropel in the deep eastern mediterranean sea has been deposited between 9 and 6 ka bp climate conditions as revealed by the pollen records of this sapropel in marine cores were most favorable for temperate deciduous trees which is in agreement with the inferences from records of peripheral land pollen sites the abundance of deciduous oak pollen is much higher than that of artemisia sage brush indicating that annual precipitation in the mid elevation borderlands was at least 550 mm without summer drought but more probably in the range 800 1300 mm the pollen of pistacia which formed a savanna at low elevations is also at its highest abundance and signals the absence of frost in winter while being capable of withstanding summer drought the early holocene therefore appears as the post glacial climatic optimum with the highest moisture and mildest winters in southwest asia this is also the time of the neolithic population explosion with incipient domestication of cereals possibly following natural selection of the tough rachis mutation in wheat and barley by the extreme aridity of the preceding younger dryas

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

geochemical characterization of contemporary fine detritus in the dead sea watershed abstract reconstruction of paleo synoptic conditions e g past atmospheric circulation involves tracing the origins and routes of transport of particles comprising eolian archives i e desert dust lacustrine deposits that accumulated in the quaternary lakes filling the dead sea basin include remobilized eolian desert dust that was washed to the lakes by floods here we analyze the mineralogical chemical compositions e g mg al ratios and 87sr 86sr and 143nd 144nd end values isotope ratios of fine siliciclastic particles that form the modern surface cover of the dead sea watershed e g loess mountain soils and flood particles that are mobilized to the lake during distinct synoptic conditions the data comprises reference data set that can be used for paleo synoptic interpretation enhancing our ability to decipher the paleoclimate history during the quaternary in the levant the end values and 87sr 86sr ratios of the fine detritus lie between 8 and 6 and 0 7035 to 0 7188 reflecting the values of erosional products of granitoids that are exposed in the sahara and arabia deserts and the unradiogenic sr from local soils in the dead sea watershed particles with low mg al ratios i e 0 17 0 31 are transported by the western winds associated with the mediterranean cyclones transporting dust from the sahara while particles with high mg al ratios 0 27 0 68 are associated with storms blowing dusts from east to the dead sea watershed saudi arabia and syrian deserts during red sea trough synoptic conditions fine particles blown from the sahara deserts during winter storms are rapidly washed to the lake by subsequent floods whereas the particles blown during dry storms associated with red sea trough synoptic conditions accumulate on the surface of the dead sea watershed and can be washed later to the lake during extensive rain events

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

variability of the western mediterranean sea surface temperature during the last 25 000 years and its connection with the northern hemisphere climatic changes sea surface temperature sst profiles over the last 25 kyr derived from alkenone measurements are studied in four cores from a w e latitudinal transect encompassing the gulf of cadiz atlantic ocean the alboran sea and the southern tyrrhenian sea western mediterranean the results document the sensitivity of the mediterranean region to the short climatic changes of the north atlantic ocean particularly those involving the latitudinal position of the polar front the amplitude of the sst oscillations increases toward the tyrrhenian sea indicating an amplification effect of the atlantic signal by the climatic regime of the mediterranean region all studied cores show a shorter cooling phase 700 years for the younger dryas yd than that observed in the north atlantic region 1200 years this time diachroneity is related to an intra yd climatic change documented in the european continent minor oscillations in the southward displacement of the north atlantic polar front may also have driven this early warming in the studied area during the holocene a regional diachroneity propagating west to east is observed for the sst maxima 11 5 10 2 kyr b p in the gulf of cadiz 10 9 kyr b p in the alboran sea and 8 9 8 4 kyr b p in the thyrrenian sea a general cooling trend from these sst maxima to present day is observed during this stage which is marked by short cooling oscillations with a periodicity of 730 40 years and its harmonics

characteristics of luminous structures in the stratosphere above thunderstorms as imaged by low light video an experiment was conducted in which an image intensified low light video camera systematically monitored the stratosphere above distant 100 800 km mesoscale convective systems over the high plains of the central u s for 21 nights between 6 july and 27 august 1993 complex luminous structures were observed above large thunderstorm clusters on eleven nights with one storm system 7 july 1993 yielding 248 events in 410 minutes their duration ranged from 33 to 283 ms with an average of 98 ms the luminous structures generally not visible to the naked dark adapted eye exhibited on video a wide variety of brightness levels and shapes including streaks aurora like curtains smudges fountains and jets the structures were often more than 10 km wide and their upper portions extended to above 50 km msl

abrupt aridities and salt deposition in the post glacial dead sea and their north atlantic connection abstract abrupt arid events in the post glacial 17 4 10 kyr bp dead sea basin dsb were recorded by significant lake level declines in lake lisan and massive deposition of gypsum and salt between 17 4 and 16 kyr cal bp the lake level dropped from its late mis2 stand of 260 m below mean sea level m bmsl to 330 m bmsl depositing a thick sequence of gypsum between 16 and 15 kyr cal bp the lake level recovered but dropped abruptly again at 14 kyr cal bp to below 465 m bmsl probably the lowest late pleistocene stand then between 13 and 11 kyr cal bp the younger dryas time interval the lake rose above 400 m bmsl and declined at 11 10 kyr cal bp depositing a thick sequence of salt the abrupt lake level drops and salt deposition coincided with times of ice and meltwater discharges into the north atlantic na heinrich event h1 and meltwater pulse mwp1a similar coincidence between ice and meltwater discharges in the na e g h events and arid episodes at the levant was recorded during the colder last glacial period demonstrating a persistent effect of the north atlantic hydrology and sea ice advances on the levant climate the climatically turmoil post glacial period was accompanied by significant developments in human culture the collapse of the natufian culture during the bolling allerod and the rise of the pre pottery neolithic cultures ppn a and b around the 11 10 kyr cal bp salt deposition interval marking the initiation of the neolithic revolution in the region

positive charge in the stratiform cloud of a mesoscale convective system a balloon sounding of electric field in the trailing stratiform cloud of a bow echo mesoscale convective system reveals only two substantial in cloud positive charge regions these charge regions are located at altitudes of 5 1 5 6 km and 6 4 6 8 km above the level of 0 c at 4 2 km the two positive charge regions are the likely sources of six positive cloud to ground flashes with large peak currents 32 ka that occurred within 60 km of the balloon during its flight the amount of charge transferred by three of these positive flashes that made q bursts is calculated in the range of 97 196 c flashes of this sort are known to produce sprites and elves in the mesosphere the positive charge regions in this stratiform cloud are substantially lower than the 10 km altitude commonly assumed for the positive charge in many sprite modeling studies

holocene climate variability and cultural evolution in the near east from the dead sea sedimentary record abstract a comprehensive record of lake level changes in the dead sea has been reconstructed using multiple well dated sediment cores recovered from the dead sea shore interpreting the lake level changes as monitors of precipitation in the dead sea drainage area and the regional eastern mediterranean palaeoclimate we document the presence of two major wet phases 10 8 6 and 5 6 3 5 cal kyr bp and multiple abrupt arid events during the holocene the arid events in the holocene dead sea appear to coincide with major breaks in the near east cultural evolution at 8 6 8 2 4 2 3 5 cal kyr bp wetter periods are marked by the enlargement of smaller settlements and growth of farming communities in desert regions suggesting a parallelism between climate and near east cultural development

mineralogical and chemical variability of mountain red brown mediterranean soils the purpose of the current study was to quantitatively explore the dynamics of clay pedogenesis in red brown soils of the terra rossa type and associated soils mainly rhodoxeralfs of the mediterranean region with respect to bedrock and dust composition and the impact of the vegetation translocated elements silicon and potassium fifteen non cultivated shallow and leached mountain pedons were sampled in israel along three transects that represent various rainfall ranges and bedrock lithologies bulk and clay fraction chemical and mineralogical compositions as well as grain size were determined quantitative relative analysis of clay minerals displayed a large variability that was largely affected by leaching leaching was dependent on rainfall amount and bedrock soil permeability in general if the better soils were drained and leached the higher were the amounts of both kaolinite and illitic phases soil clay assemblages lay between two mineralogical end members one with dominance of smectite and the second with high values of kaolinite and illitization parameters potassium and silicon were mobile in soils relative to aluminum but under high rainfall or certain vegetation translocation by vegetation reached a degree that promoted illite or smectite formation local combinations of rainfall bedrock soil permeability and vegetation translocation of potassium and silicon dictated a large variability in clays including illite formation within a restricted group of red brown mediterranean soils

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

coordinated analysis of delayed sprites with high speed images and remote electromagnetic fields 1 simultaneous measurements of high altitude optical emissions and magnetic fields produced by sprite associated lightning discharges enable a close examination of the link between low altitude lightning processes and high altitude sprite processes we report results of the coordinated analysis of high speed sprite video and wideband magnetic field measurements recorded simultaneously at yucca ridge field station and duke university from june to august 2005 sprites were detected following 67 lightning strokes all of which had positive polarity our data showed that 46 of the 83 discrete sprite events in these sequences initiated more than 10 ms after the lightning return stroke and we focus on these delayed sprites in this work all delayed sprites were preceded by continuing current moments that averaged at least 11 ka km between the return stroke and sprites the total lightning charge moment change at sprite initiation varied from 600 to 18 600 c km and the minimum value to initiate long delayed sprites ranged from 600 for 15 ms delay to 2000 c km for more than 120 ms delay we numerically simulated electric fields at altitudes above these lightning discharges and found that the maximum normalized electric fields are essentially the same as fields that produce short delayed sprites both estimated and simulation predicted sprite initiation altitudes indicate that long delayed sprites generally initiate around 5 km lower than short delayed sprites the simulation results also reveal that slow 5 20 ms intensifications in continuing current can play a major role in initiating delayed sprites

provenance of the various grain size fractions in the negev loess and potential changes in major dust sources to the eastern mediterranean abstract the isotopic composition of sr and nd and elemental concentrations e g na k ca mg al of three primary negev loess sequences trace the relative contributions of desert dust sources over the past 180 000 yr to the southeastern mediterranean we focused on the geochemical signature of the fine 20 m grain size modes of the loess to identify their respective provenances the isotopic composition of the coarse fraction falls on a mixing line of sources feeding the nile and its delta the chemical compositions of the coarse fraction and the sinai negev sand dunes are similar indicating that this fraction is the product of aeolian abrasion of the adjacent sinai negev sands in turn these sands are derived from the nile delta and transported inland the fine fraction has less negative end values and slightly deviates from the mixing line indicating an additional end member the higher end values and mg al ratios of the fine fraction are relatively well correlated r2 0 64 and point to arabian dust as an additional source temporal changes in the geochemical composition of loess over time reflect changes in climates of source areas and the eastern mediterranean shifts from saharan to arabian fine dust dominated intervals indicate wetter conditions in the southern sahara that weaken dust fluxes from this source relative to the arabian fluxes

the sharav cyclone observations and some theoretical considerations a special study of the sharav cyclones indicates that they are the result of large scale weak baroclinicity enhanced by vigorous boundary layer baroclinicity between the north african coast and the mediterranean it is illustrated how the jet stream plays a major role in the vertical circulation in producing a complex cyclonic circulation dominated by at least three mechanisms large scale interior baroclinicity boundary layer baroclinicity and jet stream related circulations the main characteristics of the sharav cyclone also called the saharan depression or khamsin depression in the mediterranean are reviewed unlike the cold winter cyclone the sharav cyclone is a spring cyclone its tracks lie mainly along the north african coast and turn to the north near the southeastern mediterranean its warm front is active and is sometimes associated with extremely high surface temperatures its cold front is shallow the sharav cyclone moves eastward relatively fast typically faster than 10 m s 1 and with a small speed variability in general there is an upper level trough to the west of the surface low and the surface horizontal scale is of the order of 500 1000 km finally it is frequently associated with heavy dust sand storms and low visibilities some of these features are illustrated in a case study of the april 28 30 1986 cyclone vertical cross sections indicate a deep circulation associated with the exit region of an upper level jet in addition to presenting evidence that the sharav cyclone is a deep tropospheric circulation it is shown that the transverse indirect circulation at the exit region of the jet is a major component of its circulation the classic two level baroclinic model phillips 1954 is applied the effects of the major diabatic heating due to the sensible heat flux above the north african desert and the large north to south temperature gradients are incorporated through the thermal wind of the basic state the model predicts the fast eastward motion the relatively smaller horizontal scale and the fast growth rate furthermore the model predicts an annual maximum growth rate in april and a secondary peak in october which agrees with the frequency of occurrences of the sharav cyclones

lightning location relative to storm structure in a leading line trailing stratiform mesoscale convective system 1 horizontal and line normal vertical cross sections and composite images of dallas fort worth lightning detection and ranging ldar ii vhf radiation sources and radar reflectivity over a 30 min period provide a unique perspective on lightning pathways within a leading line trailing stratiform llts mesoscale convective system mcs on 16 june 2002 the overwhelming majority of vhf lightning sources occurred within the leading convective line in a bimodal pattern in the vertical assuming that vhf source density maxima were most likely associated with positive charge then the ldar ii observations suggest that the gross charge structure of the convective region of the mcs was characterized by a tripole with net positive charge centered at 4 5 km agl 3 c and 9 5 km agl 35 c and net negative charge centered roughly in the relative minimum of the vhf source density maximum at 7 km agl 17 c a persistent lightning pathway and inferred positive charge zone sloped rearward by 40 50 km and downward by 4 5 km from the upper vhf source maximum in the convective line through the transition zone and into the radar bright band of the stratiform region in the stratiform region vhf lightning sources and inferred positive charge were concentrated in three layers centered at 4 5 6 and 9 km agl 2 c 11 c and 31 c respectively consistent with past electric field studies of symmetric llts mcss positive cloud to ground lightning flashes in the stratiform region were initiated in the convective line and followed the slanting pathway from the top of convective cores to the stratiform precipitation where they were horizontally extensive layered and highly branched the sloping lightning pathway was identical to hypothetical trajectories taken by snow particles these observations provide further support for the advection of charge on snow along the sloping pathway and the in situ generation of charge in the horizontal lightning layers as primary contributors to electrification and positive lightning production rearward of the convective line

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