late quaternary palaeoenvironment of northern guatemala evidence from deep drill cores and seismic stratigraphy of lake peten itza long sediment cores were collected in spring 2006 from lake peten itza northern guatemala in water depths ranging from 30 to 150 m as part of an international continental scientific drilling program project the sediment records from deep water consist mainly of alternating clay gypsum and carbonate units and in at least two drill sites extend back 200 kyr most of the lithostratigraphic units are traceable throughout the basin along seismic reflections that serve as seismic stratigraphic boundaries and suggest that the lithostratigraphy can be used to infer regional palaeoenvironmental changes a revised seismic stratigraphy was established on the basis of integrated lithological and seismic reflection data from the basin from ca 200 to ca 85 ka sediments are dominated by carbonate clay silt often interbedded with sandy turbidites indicating a sediment regime dominated by detrital sedimentation in a relatively humid climate at ca 85 ka an exposure horizon consisting of gravels coarse sand and terrestrial gastropods marks a lake lowstand or partial basin desiccation indicating dry climate conditions from ca 85 to ca 48 ka transgressive carbonate clay sediments overlain by deep water clays suggest a lake level rise and subsequent stabilization at high stage from ca 48 ka to present the lithology is characterized by alternating clay and gypsum units gypsum deposition correlates with heinrich events i e dry climate whereas clay units coincide with more humid interstadials

chronostratigraphy of the 600 000 year old continental record of lake van turkey lake van sediment cores from the ahlat ridge and northern basin drill sites of the icdp project paleovan contain a wealth of information about past environmental processes the sedimentary sequence was dated using climatostratigraphic alignment varve chronology tephrostratigraphy argon argon single crystal dating radiocarbon dating magnetostratigraphy and cosmogenic nuclides based on the lithostratigraphic framework the different age constraints are compiled and a robust and precise chronology of the 600 000 year old lake van record is constructed proxy records of total organic carbon content and sediment color together with the calcium potassium ratios and arboreal pollen percentages of the 174 meter long ahlat ridge record mimic the greenland isotope stratotype ngrip therefore the proxy records are systematically aligned to the onsets of interstadials reflected in the ngrip or synthesized greenland ice core stratigraphy the chronology is constructed using 27 age control points derived from visual synchronization with the gicc05 timescale an absolutely dated speleothem record e g hulu sanbao linzhu cave and the epica dome c timescale in addition the uppermost part of the sequence is complemented with four ages from holocene varve chronology and two calibrated radiocarbon ages furthermore nine argon argon ages and a comparison of the relative paleointensity record of the magnetic field with reference curve piso 1500 confirm the accuracy of the age model also the identification of the laschamp event via measurements of 10be in the sediment confirms the presented age model the chronology of the ahlat ridge record is transferred to the 79 meter long event corrected composite record from the northern basin and supplemented by additional radiocarbon dating on organic marco remains the basal age of the northern basin record is estimated at 90 ka the variations of the time series of total organic carbon content the ca k ratio and the arboreal pollen percentages illustrate that the presented chronology and paleoclimate data are suited for reconstructions and modeling of the quaternary and pleistocene climate evolution in the near east at millennial timescales furthermore the chronology of the last 250 kyr can be used to test other dating techniques

lake level and climate records of the last 90 ka from the northern basin of lake van eastern turkey abstract sedimentary geochemical and mineralogical analyses of the icdp cores recovered from the northern basin nb of lake van provide evidence of lake level and climatic changes related to orbital and north atlantic climate system over the last 90 ka high lake levels are generally observed during the interglacial and interstadial periods which are marked by deposition of varved sediments with high total organic carbon toc total inorganic carbon tic low detrital influx high ca f and high 18o and 13c values of authigenic carbonate during the glacial and stadial periods of 71 58 ka bp marine isotope stage 4 mis4 and end of last glaciation deglaciation 30 14 5 ka bp mis3 relatively low lake levels prevailed and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates millennial scale variability of the proxies during 60 30 ka bp mis3 is correlated with the dansgaard oeschger d o and holocene abrupt climate events in the atlantic these events are characterized by laminated sediments with high toc tic ca fe 18o and 13c values the lake van nb records correlate well in the region with the climate records from the lakes zeribar and urmia in iran and the sofular cave in nw anatolia but are in general in anti phase to those from the dead sea basin lake lisan in the levant the relatively higher 18o values 0 to 0 4 for the interglacial and interstadial periods in the lake van nb section are due to the higher temperature and seasonality of precipitation and higher evaporation whereas the lower values 0 8 to 2 during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation the high 18o values up to 4 2 during the younger dryas together with the presence of dolomite and low toc contents supports evaporative conditions and low lake level a gradual decrease in the 18o values from an average of 0 4 during the humid early holocene to an average of 3 5 during the more arid late holocene suggests an increasing contribution of winter precipitation the changes in the seasonality of precipitation in eastern anatolia are probably caused by changes in the temperatures of north atlantic and mediterranean and in the strength of siberian high

evidence of lateglacial and holocene climatic change and human impact in eastern anatolia high resolution pollen charcoal isotopic and geochemical records from the laminated sediments of lake van turkey annually laminated sediments from lake van spanning about 13000 varve years were sampled for stable isotopic geochemical pollen and charcoal analyses in order to find evidence of past regional climatic changes and human impact in the semi arid region of eastern anatolia turkey the lateglacial period was cold and dry with steppe vegetation and saline lake water during the younger dryas the lake level dropped dramatically and the vegetation turned to a semi desert geochemical and isotopic records indicate a strong increase in moisture at the onset of the holocene and artemisia chenopod steppes were partly replaced by grass steppe and pistachio scrub a delay of about 3000 years in the expansion of deciduous oak woodlands and high steppe fire frequencies suggest dry spring and summer weather during the early holocene at 8200 yr bp a shift in the regional climate regime facilitated the transport of more moisture into the interior areas of the taurus mountains and caused a change in the seasonal distribution of precipitation the steppe forests dominated by quercus advanced and reached their maximum extention at about 6200 yr bp all the proxy data indicate optimum climatic conditions low water salinity and high lake level between 6200 and 4000 yr bp after 4000 yr bp aridity increased again and the modern climatic situation was established human impact in the catchment of lake van started at 3800 yr bp and was intensified during the last 600 years

biogenic silica dissolution in sediments of the southern ocean i solubility abstract a stirred flow through reactor technique was used to determine silica solubilities in sediments collected with a multicorer in the indian sector of the southern ocean antares i cruise the results show that the apparent silica solubility in the cores may decrease increase or remain constant with depth the silica solubility profiles are best explained by the early diagenetic interactions between biogenic silica and soluble aluminum derived from detrital material by combining the solubility data with measured dissolved silica profiles it is shown that the variable asymptotic pore water silica levels in the cores cannot be explained solely by differences in silica solubility in sediments that experience a significant detrital input the simultaneous reprecipitation of dissolved aluminum and dissolved silica prevents water silicic acid from reaching saturation with the dissolving biogenic silica the principal oceanographic control on pore water silica build up in the cores studied is the ratio of the deposition fluxes of biogenic silica and detrital material solubility differences inherited from the biomineralization process in the surface waters do not appear to have a significant effect on the observed pore water silica levels

microbial abundance in lacustrine sediments a case study from lake van turkey the icdp paleovan drilling campaign at lake van turkey provided a long 100 m record of lacustrine subsurface sedimentary microbial cell abundance after the icdp campaign at potrok aike argentina this is only the second time deep lacustrine cell counts have been documented two sites were cored and revealed a strikingly similar cell distribution despite differences in organic matter content and microbial activity although shifted towards higher values cell counts from lake potrok aike argentina reveal very similar distribution patterns with depth the lacustrine cell count data are significantly different from published marine records the most probable cause is differences in sedimentary organic matter composition with marine sediments containing a higher fraction of labile organic matter previous studies showed that microbial activity and abundance increase centimetres to metres around geologic interfaces the finely laminated lake van sediment allowed studying this phenomenon on the microscale we sampled at the scale of individual laminae and in some depth intervals we found large differences in microbial abundance between the different laminae this small scale heterogeneity is normally overlooked due to much larger sampling intervals that integrate over several centimetres however not all laminated intervals exhibit such large differences in microbial abundance and some non laminated horizons show large variability on the millimetre scale as well the reasons for such contrasting observations remain elusive but indicate that heterogeneity of microbial abundance in subsurface sediments has not been taken into account sufficiently these findings have implications not just for microbiological studies but for geochemistry as well as the large differences in microbial abundance clearly show that there are distinct microhabitats that deviate considerably from the surrounding layers

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

eight glacial cycles from an antarctic ice core the antarctic vostok ice core provided compelling evidence of the nature of climate and of climate feedbacks over the past 420 000 years marine records suggest that the amplitude of climate variability was smaller before that time but such records are often poorly resolved moreover it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records here we report the recovery of a deep ice core from dome c antarctica that provides a climate record for the past 740 000 years for the four most recent glacial cycles the data agree well with the record from vostok the earlier period between 740 000 and 430 000 years ago was characterized by less pronounced warmth in interglacial periods in antarctica but a higher proportion of each cycle was spent in the warm mode the transition from glacial to interglacial conditions about 430 000 years ago termination v resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases but there are significant differences in the patterns of change the interglacial stage following termination v was exceptionally long 28 000 years compared to for example the 12 000 years recorded so far in the present interglacial period given the similarities between this earlier warm period and today our results may imply that without human intervention a climate similar to the present one would extend well into the future

facies characterization based on physical properties from downhole logging for the sediment record of lake van turkey abstract lake van turkey is the 4th largest terminal lake in the world and is located at a key position for climatic reconstruction the icdp project paleovan is a deep drilling campaign initiated in the summer of 2010 to enhance the understanding of paleoclimatic and paleoenvironmental conditions in the middle east for a period of 550 000 years multiple coring of two sites northern basin and ahlat ridge at a water depth of up to 360 m has been performed the sedimentary record is mainly composed of clayey silts and tephra deposits that were supplied by four volcanic sources 1 the suphan volcano located on the northern shore 2 the nemrut volcano 15 km west of the westernshore 3 the incekaya volcano on the southwestern shore and 4 intralake eruptive centers the dominant chemical composition of the volcanic sources is known from studies of land deposits high quality downhole logs have been acquired from both sites to construct a continuous lithological profile 180 m of downhole logging data from the ahlat ridge have been analyzed by cluster analysis to improve the differentiation of the sediments two elemental intensity profiles from x ray fluorescence core scanning calcium and zirconium performed on the composite profile core material were added to the cluster analysis five cluster units were derived and transformed into three tephra and two clayey silt units to compare the two clayey silt units with the composite profile from the visual core description vcd that showed 15 lithological units the composite profile was classified into two major groups of lacustrine sediments banded clayey silts interpreted as glacial deposits and laminated clayey silts interpreted as interglacial deposits despite this simplification no correlation between the two clayey silt units derived from cluster analysis and the banded and laminated clayey silts could be found the following reasons are proposed a the comparability of the datasets was limited by significant depth shifts of up to 2 5 m between the composite profile based on the vcd and the downhole measurements in hole 2d of the ahlat ridge b a correlation was difficult to ascertain from the vertical resolution of the downhole logging data and the extremely detailed core description in mm scale c mixed signals were obtained because of prevailing thin layers and intercalations of different lithotypes and d cluster analysis was difficult to perform because the contrast within the input data is too low possibly background sedimentation to distinguish between glacial and interglacial deposits tephra units are characterized by contrasting properties and differ mainly in their magnetic susceptibility spectral gamma ray components uranium thorium and potassium and xrf intensities of calcium and zirconium tephra units have been linked to the dominant volcanic composition of the deposited tephra layers and partly to the volcanic sources depth trends are derived with prevailing basaltic deposits in the bottom part 128 m 210 m below lake floor and are gradually outweighed by the highly differentiated dacitic and rhyolitic trachytic products towards the top of the record

impact of volcanism on the evolution of lake van ii temporal evolution of explosive volcanism of nemrut volcano eastern anatolia during the past ca 0 4ma thirty two new single crystal ages document 400 000 years of widespread explosive volcanism of historically active nemrut volcano towering over huge alkaline lake van eastern anatolia the dated deposits were selected to monitor the volcanic and compositional evolution of nemrut volcano through time and thus to provide a rigorous temporal framework for the tephra record of the paleovan drilling project tephra samples were taken from large volume deposits or those that occur in medial to distal localities well exposed stratigraphic sections or from the initial phase of an eruptive sequence mainly fallout deposits were chosen because most ignimbrites show more complex and corroded feldspar populations owing to compositional zoning and magma mixing moreover fallout deposits held the promise to be more clearly identifiable with and correlatable to 300 tephra layers in the paleovan drill cores even though commonly in amounts marginal or insufficient in thickness to allow well supported single crystal dating the crystals dated are dominantly anorthoclase the main phenoctyst phase in the trachytic to rhyolitic slightly to strongly peralkaline nemrut magmas ages obtained so far range from ca 400 ka to ca 30 ka for nemrut volcano the causes of significant changes in the frequency volume and composition of tephra layers per unit time are discussed in terms of external erosion climate changes geodynamic factors and internal forcing changes in magma supply and composition and incubation periods preceding large volume rhyolitic eruptions for example the low frequency of tephra layers deposited prior to ca 200 ka may be due to low explosive activity severe erosion between mis 9 and mis 11 or both nevertheless the overall frequency of explosive eruptions appears to have increased during the past ca 200 ka we also recognize a slight peak in explosive eruptions during warm periods e g mis 5 and mis 7 and speculate on lithospheric unloading triggering increased partial melting or magma reservoir unloading following massive glacier melting the ages of 5 dated ignimbrites span ca 250 000 years suggesting that nemrut volcano went through a polycyclic evolution with multiple caldera collapses and major pyroclastic flow eruptions the oldest dated so far as 265 ka the widely held view of the impressive nemrut caldera now dated to have formed at ca 30 ka as the main paroxysmal event during the evolution of the volcano is no longer tenable distinct and coherent compositional characteristics especially in trace element concentrations characterize several groups of trachytic tephras we speculate that the growth of nemrut volcano caused the isolation of the lake van basin on account of their mineralogical anorthoclase hedenbergite fayalite aenigmatite and alkalic chemical compositions and large volume dated nemrut fallout tephras are likely to represent excellent markers in lakes and other sites of paleoclimatological or archeological interest in neighboring countries to the northeast of lake van as far as the caspian sea in what may be called the east anatolian tephra province

high benthic methane flux in low sulfate oceans evidence from carbon isotopes in late cretaceous antarctic bivalves abstract the shell material of marine benthic bivalves provides a sensitive archive of water chemistry immediately above the sediment water interface which in turn is affected by sedimentary geochemistry and redox reactions sulfate has a major controlling effect on sedimentary carbon cycling particularly the processes of methane production and oxidation with lower concentrations of sulfate likely resulting in an increase in sedimentary methane production whilst it is accepted that ocean sulfate varied markedly across the phanerozoic evidence of changes in methane production in sediments has so far been lacking there is potential for the oxidation products of sedimentary methane to be preserved and detected in marine fossils here we present the results of high resolution carbonate isotope records from two taxa of well preserved shallow infaunal bivalve lahillia and cucullaea collected from the marine shelf succession across the cretaceous paleogene k pg boundary in seymour island antarctica the succession has pre existing subtle indications of more abundant methane and the time period is characterized by much lower marine sulfate concentrations than modern these shell carbonate carbon isotope records vary widely at one extreme shells have typical average values and small ranges compatible with a contemporaneous marine dissolved inorganic carbon dic source and modern style sedimentary carbon cycling at the other the shells have large amplitude annual cycles of carbon isotopic variability of up to 23 8 within a single year of growth and shell carbonate 13 c compositions as negative as 34 shells with these increased ranges and unusually negative values are found at discrete intervals and across both bivalve taxa the contribution of methane required to explain the most negative carbonate carbon isotopic values in the bivalve shells is extremely high between 30 to 85 of bottom water dic based on mass balance calculations records of organic carbon isotopes from the same succession remained between 26 1 and 21 7 throughout suggesting that methane influence was restricted to bottom waters a lack of authigenic carbonate in the section indicates that methane oxidation progressed aerobically and may have provided a significant driver for transient bottom water de oxygenation where methane addition is indicated the seasonal sensitivity precludes control by methane hydrates we argue that these data represent the increased importance and sensitivity of methanogenesis in the sediments enabled by lower ocean sulfate concentrations during the late cretaceous the tendency towards a more dynamic role for marine methane production and oxidation is likely to apply to other times of low marine sulfate in earth s history

800 000 years of abrupt climate variability we constructed an 800 000 year synthetic record of greenland climate variability based on the thermal bipolar seesaw model our greenland analog reproduces much of the variability seen in the greenland ice cores over the past 100 000 years the synthetic record shows strong similarity with the absolutely dated speleothem record from china allowing us to place ice core records within an absolute timeframe for the past 400 000 years hence it provides both a stratigraphic reference and a conceptual basis for assessing the long term evolution of millennial scale variability and its potential role in climate change at longer time scales indeed we provide evidence for a ubiquitous association between bipolar seesaw oscillations and glacial terminations throughout the middle to late pleistocene

environmental history of southern patagonia unravelled by the seismic stratigraphy of laguna potrok aike laguna potrok aike located in southernmost patagonia argentina 52s is a 100 m deep hydrologically closed lake that probably provides the only continental southern patagonian archive covering a long and continuous interval of several glacial to interglacial cycles in the context of the planned international continental scientific drilling program initiative potrok aike maar lake sediment archive drilling project several seismic site surveys that characterize in detail the sedimentary subsurface of the lake have been undertaken long sediment cores recovered the material to date and calibrate these seismic data laguna potrok aike is rimmed steeply circular in shape with a diameter of 3ae5 km and is surrounded by a series of subaerial palaeoshorelines reflecting varying lake level highstands and lowstands seismic data indicate a basinwide erosional unconformity that occurs consistently on the shoulder of the lake down to a depth of 33 m below 2003 ad lake level marking the lowest lake level during late glacial to holocene times cores that penetrate this unconformity comprise marine isotope stage 3 dated sediments 45 kyr bp 3ae5 m below and post 6800 cal yr bp transgressional sediments above the unconformity this middle holocene transgression following an unprecedented lake level lowstand marks the onset of a stepwise change in moisture as shown by a series of up to 11 buried palaeoshorelines that were formed during lake level stillstands at depths between 30 and 12 m two series of regressive shorelines between 5800 to 5400 and 4700 to 4000 cal yr bp interrupt the overall transgressional trend in the basin mound like drift sediments occur after 6000 cal yr bp documenting the onset of lake currents triggered by a latitudinal shift or an increase in wind intensity of the southern hemispheric westerlies over laguna potrok aike at that time furthermore several well defined lateral slides can be recognized the majority of these slides occurred during the mid holocene lake level lowering when the slopes became rapidly sediment charged because of erosion from the exposed shoulder sediments around 7800 and 4900 cal yr bp several slides went down simultaneously probably triggered by seismic shaking

magma generation by slab steepening and breakoff beneath a subduction accretion complex an alternative model for collision related volcanism in eastern anatolia turkey 1 eastern anatolia is regarded as one of the best examples of continental collision represented by a 2 km high plateau it displays shallow and diffuse seismicity indicating that the crust is still being actively deformed perhaps the most striking aspect of eastern anatolia is the volume and compositional variability of collision related volcanic products erupted during the neogene and quaternary time a number of models have been proposed for the genesis of this volcanism in the region however recent geophysical studies have revealed that a mantle lithosphere is almost completely absent beneath a greater portion of the region which makes us question the validity of the previous models in this paper we propose a new model for magma genesis slab steepening and breakoff beneath a large subduction accretion complex this model holds that a northward subducting oceanic lithosphere beneath the eastern anatolia accretionary prism gets steepened and eventually detached from the continental lithosphere of the bitlis poturge massif following the continent accretionary complex collision this brings the asthenospheric mantle in contact with the accretionary complex at shallow depths e g around 50 km resulting in rapid regional uplift and extensive melting which leads to collisional volcanism

biomarkers in lake van sediments reveal dry conditions in eastern anatolia during 110 000 10 000 years b p lipid biomarkers were analyzed in lake van sediments covering the last 600 ka with a focus on the period between 110 and 10 ka when a broad maximum in pore water salinity as a relict from the past suggests dry conditions the occurrence and distribution of biomarkers indicative for terrestrial plants long chain n alkane c29 haptophyte algae methyl alkenones c37 and halophilic archaea archaeol all point toward a dry climate in lake van region during this time interval the hydrogen isotopic composition of c29 n alkanes dc29 and c37 alkenones dc37 is enriched between mis 4 and mis 2 which is interpreted as a decrease in the regional ratio of precipitation to evaporation similarly the low abundance of the acyclic glycerol dialkyl glycerol tetraether gdgt 0 relative to archaeol quantified by the archaeol and caldarchaeol ecometric ace is assumed to reflect the presence of halophilic euryarchaeota adapted to high salinity water the climate around lake van appears in phase with the yammouneh basin 800 km southwest and lake urmia 250 km southeast of lake van over the last two glacial periods the results highlight the potential of combining ace dc29 and dc37 for reconstructing salinity changes and regional precipitation to evaporation ratio from lake sediments

prehistoric earthquake history revealed by lacustrine slump deposits five strong paleoseismic events were recorded in the past 15 k y in a series of slump deposits in the subsurface of lake lucerne central switzerland revealing for the first time the paleoseismic history of one of the most seismically active areas in central europe although many slump deposits in marine and lacustrine environments were previously attributed to historic earthquakes the lack of detailed three dimensional stratigraphic correlation in combination with accurate dating hampered the use of multiple slump deposits as paleoseismic indicators this study investigated the fingerprint of the well described a d 1601 earthquake i vii viii mw 6 2 in the sediments of lake lucerne the earthquake triggered numerous synchronous slumps and megaturbidites within different subbasins of the lake producing a characteristic pattern that can be used to assign a seismic triggering mechanism to prehistoric slump events for each seismic event horizon the slump synchronicity was established by seismic stratigraphic correlation between individual slump deposits through a quasi three dimensional high resolution seismic survey grid four prehistoric events dated by accelerator mass spectrometry 14c measurements and tephrochronology on a series of long gravity cores occurred at 2420 9770 13 910 and 14 560 calendar yr ago these recurrence times are essential factors for assessing seismic hazard in the area the seismic hazard for lakeshore communities is additionally amplified by slump induced tsunami and seiche waves numerical modeling of such tsunami waves revealed wave heights to 3 m indicating tsunami risk in lacustrine environments

erratum to impact of volcanism on the evolution of lake van ii temporal evolution of explosive volcanism of nemrut volcano eastern anatolia during the past ca 0 4 ma j volcanol geotherm res 253 2013 15 34

rapid environmental changes in southern europe during the last glacial period oxygen isotope records from greenland ice cores1 2 indicate numerous rapid climate fluctuations during the last glacial period north atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of ice rafted debris3 4 5 in contrast very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents here we present high resolution geochemical physical and pollen data from lake sediments in italy and from a mediterranean sediment core linked by a common tephrochronology our lacustrine sequence extends to the past 102 000 years many of its features correlate well with the greenland ice core records demonstrating that the closely coupled ocean atmosphere system of the northern hemisphere during the last glacial4 extended its influence at least as far as the central mediterranean region numerous vegetation changes were rapid frequently occurring in less than 200 years showing that the terrestrial biosphere participated fully in last glacial climate variability earlier than 65 000 years ago our record shows more climate fluctuations than are apparent in the greenland ice cores together the multi proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials and provide a step towards determining the underlying mechanisms of the centennial millennial scale variability

refining the interpretation of lacustrine carbonate isotope records implications of a mineralogy specific lake van case study abstract oxygen and carbon isotope 18o and 13c data from bulk carbonates are widely applied proxies for temperature the precipitation evaporation ratio and productivity in lacustrine palaeohydrology and palaeoclimatology in case of the terminal and alkaline lake van however previous studies have shown that bulk oxygen isotope compositions are in disagreement with other proxies when interpreted in a conventional manner similarly the reports on the nature and the timing and site of carbonate precipitation in lake van are inconsistent this study provides evidence on the mineralogy x ray powder diffraction analysis scanning electron microscope imaging confocal raman microscopy electron microprobe analysis and isotope composition 18o and 13c of non skeletal carbonate minerals in a lake van sedimentary profile spanning the last ca 150 kyr carbonate phases present in the sediment include aragonite low mg calcite and calcian dolomite dolomite forms as an early diagenetic phase and occurs episodically in high concentrations driving the bulk isotope record towards the higher dolomite 18o and varying 13c values aragonite and low mg calcite precipitate in the surface water and are present in the sediments in varying amounts relative aragonite to calcite content for dolomite poor samples ar ar cc of 93 to 41 wt in an attempt to explain this variation we revised a precipitation model based on annually laminated sediments containing both aragonite and calcite spatially separated in light and dark coloured laminae respectively according to our model spring calcite precipitation under close to freshwater conditions is followed by evapoconcentration driven aragonite precipitation in late summer the precipitation of these carbonate polymorphs from chemically differing surface waters i e freshwater influenced and evapoconcentrated leads to distinctly different oxygen and carbon isotope signatures between sedimentary penecontemporaneous aragonite and calcite the 18o and 13c values of aragonite relative to calcite are significantly higher by several per mille than inferred from aragonite calcite fractionation factors alone suggesting that the generalised assumption of sedimentary coeval calcite and aragonite precipitating from water with the same isotopic composition is flawed the here proposed revised hydrologically separated carbonate precipitation model is not only taking i differences in the isotopic fractionation between carbonate minerals into account but also ii considering the hydrological conditions and the processes favouring the precipitation of a given mineral and ultimately controlling its isotopic composition if mixed mineralogies are present this mineralogy specific approach has the potential of refining environmental reconstructions and reconciling apparently equivocal interpretations of different proxy records

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

biomarker seasonality study in lake van turkey the endorheic lake van in eastern anatolia turkey is the world s largest soda lake and it is an important site in paleoclimate studies to understand past continental conditions in western asia in order to gain further insights into the biomarker signatures in lake van s sediments we have analyzed particulate material in sediment traps deployed between august 2006 and july 2007 the biomarkers used were long chain alkenones lcas c37 c39 haptophyte lipids isoprenoid glycerol dialkyl glycerol tetraethers gdgts archaea membrane lipids and pigments chlorins and fucoxanthin the biomarker fluxes indicate a strong seasonality in export primary productivity and the phytoplankton community structure the highest total mass and organic carbon fluxes were found in summer coupled to strong stratification while the lowest mass fluxes occurred in winter at the time of water column mixing with increasing temperatures in early spring phytoplankton export productivity grew coupled with an increase of total mass flux and organic carbon which might be associated to enhanced nutrient input from snowmelt runoff the percentage of c37 4 shows some correspondence with observed seasonal changes in lake van s stratification structure we also evaluated the potential applicability of molecular temperature proxies derived from archaea and haptophyte lipids the use of the tex86 proxy was precluded by low gdgt abundances estimated lca temperatures were consistent with temperatures in the photic zone but no seasonality changes were observed despite the wide annual temperature range measured at lake van 2011 elsevier ltd all rights reserved

orbital and millennial antarctic climate variability over the past 800 000 years a high resolution deuterium profile is now available along the entire european project for ice coring in antarctica dome c ice core extending this climate record back to marine isotope stage 20 2 800 000 years ago experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation we assessed the general correspondence between dansgaard oeschger events and their smoothed antarctic counterparts for this dome c record which reveals the presence of such features with similar amplitudes during previous glacial periods we suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records

millennial to orbital scale variations of drought intensity in the eastern mediterranean abstract millennial to orbital scale rainfall changes in the mediterranean region and corresponding variations in vegetation patterns were the result of large scale atmospheric reorganizations in spite of recent efforts to reconstruct this variability using a range of proxy archives the underlying physical mechanisms have remained elusive through the analysis of a new high resolution sedimentary section from lake van turkey along with climate modeling experiments we identify massive droughts in the eastern mediterranean for the past four glacial cycles which have a pervasive link with known intervals of enhanced north atlantic glacial iceberg calving weaker atlantic meridional overturning circulation and dansgaard oeschger cold conditions on orbital timescales the topographic effect of large northern hemisphere ice sheets and periods with minimum insolation seasonality further exacerbated drought intensities by suppressing both summer and winter precipitation

the annual particle cycle in lake van turkey abstract the varved sediments of lake van provide a high quality continental archive of seasonal to decadal scale climate variability in order to read the natural record modern varve formation was studied on the basis of 1 remotely sensed total suspended matter tsm rs concentrations 2 time series of particle flux and water temperatures and 3 turbidity temperature and oxygen profiles tsm rs validated by contemporaneous water column sampling shows great temporal and lateral variations whitings and turbidity plumes from 2006 to 2009 sequential sediment traps recorded high particle fluxes during spring and fall medium fluxes during summer and almost zero flux during winter the mean total mass flux of 403 mg m 2 day 1 comprised 33 seasonally up to 67 calcium carbonate 7 aquatic organic matter 6 biogenic opal and 54 detrital minerals the caco 3 fluxes are controlled by river discharge precipitation and snowmelt during spring by high productivity during summer and by river discharge precipitation before snowfall starts and mixing during fall in november 2007 an anomalously high caco 3 flux occurred as a result of a warm water surface supersaturated with calcite coinciding with an anomalous runoff event the results demonstrate that the couplets of light and dark laminae in the short sediment cores are true varves representing spring summer fall and winter conditions respectively consequently varve formation can be linked to the seasonal climate pattern providing a calibration that can be used to interpret the partially varved paleo record of lake van and related environmental processes

impact of volcanism on the evolution of lake van i evolution of explosive volcanism of nemrut volcano eastern anatolia during the past 400 000 years the historically active nemrut volcano 2 948 m asl eastern anatolia rising close to the western shore of huge alkaline lake van has been the source of intense plinian eruptions for 530 000 years drilled lake sediments about 40 widespread newly recognized trachytic and less common rhyolitic fallout tephras and ca 12 interbedded ignimbrites sourced in nemrut volcano are documented in stratigraphic traverses throughout an area of 6 000 km2 mostly west of lake van phenocrysts in the moderately peralkaline trachytes and rarer large volume comenditic rhyolites comprise anorthoclase hedenbergite augite fayalite and especially in trachytic units augite minor aenigmatite apatite and quartz and rare chevkinite and zircon dacitic to rhyolitic tephras from nearby calcalkalic suphan volcano 4 058 m asl locally interbedded with nemrut tephras are characterized by disequilibrium phenocryst assemblages biotite augitic clinopyroxene and hypersthene minor olivine common crystal clots and or in some deposits amphibole the magma volume dre of the largest nemrut tephra sheet ap 1 described in detail may exceed 30 km3 extreme facies and systematic compositional changes are documented in the ca 30 ka nemrut formation nf deposits formed from one large and complex eruption thick rhyolitic fallout overlain by ignimbrite welded agglutinate overbank surge deposits and final more mafic fallout deposits common evidence of magma mixing in nemrut ignimbrites reflects eruption from compositionally zoned magma reservoirs several young cekmece formation trachytes overlying ca 30 ka old nf deposits and the late trachytes of the nf deposits show compositional affinities to tephra from suphan volcano possibly due to temporary influx of suphan magmas into the nemrut system following the evacuation of 10 km3 magma dre during the caldera forming nf eruption axes of large fallout fans are dominantly sw ne but w e in the younger sheets resembling the direction of the present dominant wind field growth of nemrut volcanic edifice and its peripheral domes since before 0 5 ma in the hinge area between the van and mus tectonic basins is likely to have been the major factor in isolating lake van basin thus initiating the origin and subsequent alkaline evolution of the lake this alkalinity was later significantly controlled by climate forcing internal forcing mechanisms volcanic and geodynamic may also have contributed to major lake level changes in addition to climate forcing

ice age terminations 230th dated oxygen isotope records of stalagmites from sanbao cave china characterize asian monsoon am precipitation through the ends of the third and fourthmost recent ice ages as a result am records for the past four glacial terminations can now be precisely correlated with those from ice cores and marine sediments establishing the timing and sequence of major events in all four cases observations are consistent with a classic northern hemisphere summer insolation intensity trigger for an initial retreat of northern ice sheets meltwater and icebergs entering the north atlantic alter oceanic and atmospheric circulation and associated fluxes of heat and carbon causing increases in atmospheric co2 and antarctic temperatures that drive the termination in the southern hemisphere increasing co2 and summer insolation drive recession of northern ice sheets with probable positive feedbacks between sea level and co2

paleoenvironmental and paleoclimatic variations around lake van eastern turkey recorded by sedimentary source specific biomarkers 250 130 ka mis7 and mis6 abstract paleoclimatic changes during mis7 and mis6 remain poorly described in the near east we quantified source specific biomarkers in lake van sediments during the interglacial glacial cycle mis7 mis6 long chain n alkanes produced by land derived vegetation as well as long chain alkenones and sterols namely brassicasterol and dinosterol produced by aquatic algae were investigated stable hydrogen isotopic measurements 2h on n c29 alkanes were used as a proxy for aridity and revealed three wetter periods interrupted by two drier intervals during mis7 in contrast during the mis6 glaciation a generally drier climate was predominant during the warmer and wetter periods of mis7 a higher input of aquatic organic matter to lake van sediments was recorded by higher concentrations of long chain alkenones dinosterol and brassicasterol long chain alkane abundances do not show a pattern related to aridity and were observed in higher concentrations in wetter as well as drier periods generally in the eastern mediterranean a wetter interglacial interrupted by drier episodes followed by a dry glacial period was the common feature observed during the mis7 mis6 interglacial glacial cycle however in comparison to the last interglacial glacial cycle the extreme dry glacial period registered around lake van from mis5d to mis2 was apparently unique and not equaled by a similar event within the last 250 ka

tsunami induced sediment transport in the abyssal mediterranean sea an unusual stratigraphic unit nicknamed homogenite fills topographic lows in the complex ridge and trough bathymetry at two survey sites on the western mediterranean ridge and the calabrian ridge on near bottom 4 khz seismic reflection profiles this unit us an acoustically transparent near surface flat lying layer whereas in cores it is a homogeneous gray marl as much as 7 m thick grain size decreases upcore within the unit implying that it was deposited in a single event controlled by gravitational settling the stratigraphic position of the homogenite relative to a firmly dated sapropel bed suggests emplacement between 4400 and 3100 yr b p the source of the homogenite is inferred to be the nearby basin walls farther east two other sites with similar rugged topography lack homogenite entirely a triggering mechanism is required which is capable of initiating massive sediment transport simultaneously in many separate basins at the western two survey sites but which is not effective at the eastern sites a large archeologically recorded earthquake of the correct age is considered and rejected because its epicenter is closer to the nonhomogenite bearing sites than to the sites where this sediment type was observed and because several other earthquakes of comparable magnitude have since been recorded in the area whereas the homogenite is unique the 3 500 yr b p collapse of the caldera of the volcano of santorini caused a huge tsunami which is recorded archeologically and geologically around the eastern mediterranean because of refraction of the tsunami by the bathymetry and because the caldera collapsed in its southwest corner a disproportionate amount of tsunami energy was directed toward the western area where homogenite is observed in contrast the homogenite free sites were relatively sheltered an order of magnitude calculation shows that the near bottom oscillating currents accompanying the santorini tsunami were at or above the threshold erosion velocity at the homogenite bearing sites in addition the near bottom pressure pulse under the tsunami at the homogenite bearing sites was sufficient to cause liquefaction of sediments neither mechanism was adequate to cause sediment transport or slope failure at the homogenite free sites

dynamics of the last four glacial terminations recorded in lake van turkey abstract a well dated suite of lake van climate proxy data covering the last 360 ka documents environmental changes over 4 glacial interglacial cycles in eastern anatolia turkey the picture of cold and dry glacials and warm and wet interglacials emerging from pollen organic carbon authigenic carbonate content elemental profiling by xrf and lithological analyses is inconsistent with classical interpretation of oxygen isotopic composition of carbonates pointing to a more complex pattern in lake van region detailed analysis of glacial terminations allows for the constraining of a depositional model explaining different patterns observed in all the proxies we hypothesize that variations in relative contribution of rainfall snowmelt and glacier meltwater recharging the basin have a very important role for all sedimentary processes in lake van lake level of glacial lake van predominantly fed by snowmelt was low the water column was oxic and carbonates precipitating in the epilimnion recorded the light isotopic signature of inflow during terminations increasing rainfall and significant supply of mountain glaciers meltwater contributed to lake level rise increased rainfall enhanced density gradients in the water column and hindered mixing leading to development of bottom water anoxia carbonates precipitating during terminations show large fluctuations in their isotopic composition full interglacial conditions in lake van are characterized by high or slowly falling lake level rainfall and snowmelt feed the lake but due to re established mixing the isotopic composition of authigenic carbonates is heavier and closer to that of evaporation influenced lake water than that of runoff representing snowmelt and atmospheric precipitation

timing and climatic impact of greenland interstadials recorded in stalagmites from northern turkey a 50 kyr long exceptionally well dated and highly resolved stalagmite oxygen 18o and carbon 13c isotope record from sofular cave in northwestern turkey helps to further improve the dating of greenland interstadials gi 1 and 3 12 timing of most gi in the sofular record is consistent within 10 to 300 years with the iconic hulu cave record larger divergences 500 years between sofular and hulu are only observed for gi 4 and 7 the sofular record differs from the most recent ngrip chronology by up to several centuries whereas age offsets do not increase systematically with depth the sofular record also reveals a rapid and sensitive climate and ecosystem response in the eastern mediterranean to gi whereas a phase lag of 100 years between climate and full ecosystem response is evident finally results of spectral analyses of the sofular isotope records do not support a 1 470 year pacing of gi

high resolution record of northern hemisphere climate extending into the last interglacial period high resolution record of northern hemisphere climate extending into the last interglacial period

lithostratigraphy physical properties and organic matter variability in lake malawi drillcore sediments over the past 145 000years abstract scientific drill cores recovered from lake malawi exhibit a remarkable down core lithologic variability and are indicative of radically changing environmental conditions forced by large amplitude lake level shifts over the past 150 kyr here we present detailed lithologic and sedimentary fabric descriptions of the key sedimentary units along with down core physical properties data down core organic matter geochemistry toc c n and 13c data sets and images and descriptions from core sections and from sediment smear slide microscopy these data reveal a fundamental change in lake malawi s limnology and regional climate at ca 60 70 ka prior to this time the lake was characterized by large amplitude variations in lake level and water chemistry but after 60 ka the lake remained comparatively high and the central basin drill site accumulated mainly organic rich laminated sediments organic matter sources changed dramatically during the different lake stages during major lake high stands a mixed assemblage of algal diatom dominated woodland and aquatic macrophyte c4 pathway and grassland c3 pathway organic matter was deposited whereas during extreme low lake stages water depths

feldspar 40 ar 39 ar dating of icdp paleovan cores abstract volcaniclastic fall deposits in icdp drilling cores from lake van turkey contain sodium rich sanidine and calcium rich anorthoclase which both comprise a variety of textural zoning and inclusions an age model records the lake s history and is based on climate stratigraphic correlations tephrostratigraphy paleomagnetics and earlier 40 ar 39 ar analyses stockhecke et al 2014b results from total fusion and stepwise heating 40 ar 39 ar analyses presented in this study allow for the comparison of radiometric constraints from texturally diversified feldspar and the multi proxy lacustrine age model and vice versa this study has investigated several grain size fractions of feldspar from 13 volcaniclastic units the feldspars show textural features that are visible in cathodoluminescence cl or back scattered electron bse images and can be subdivided into three dominant zoning types 1 compositional zoning 2 round pseudo oscillatory zoning and 3 resorbed and patchy zoning ginibre et al 2004 round pseudo oscillatory zoning records a sensitive alternation of fe and ca that also reflects resorption processes this is only visible in cl images compositional zoning reflects anticorrelated anorthite and orthoclase contents and is visible in bse eleven inverse isochron ages from total fusion and three from stepwise heating analyses fit the age model four experiments resulted in older inverse isochron ages that do not concur with the model within 2 uncertainties and that deviate from 1 ka to 17 ka minimum c and r type zoning are interpreted as representing growth in magma chamber cupolas as wall mushes or in narrow conduits persistent compositions of po type crystals and abundant surfaces recording dissolution features correspond to formation within a magma chamber c type zoning and r type zoning have revealed an irregular incorporation of melt and fluid inclusions these two types of zoning in feldspar are interpreted as preferentially contributing either heterogeneously distributed excess 40 ar or inherited 40 ar to the deviating 40 ar 39 ar ages that are discussed in this study

noble gases in the sediments of lake van solute transport and palaeoenvironmental reconstruction abstract sediment samples acquired in 2010 from the long cores of the international continental scientific drilling program icdp paleovan drilling project on lake van for noble gas analysis in the pore water allow determination of the local terrestrial he gradient as a function of depth within a sediment column of more than 200 m these measurements yield first insights into the physical transport mechanisms of terrigenic he through the uppermost part of unconsolidated lacustrine sediments overlying the continental crust in line with our previous work on the spatial distribution of the terrigenic he release into lake van we identify a high he concentration gradient in the uppermost 10 m of the sediment column the he concentration gradient decreases below this depth down to approx 160 m following in general the expectations of the modelling of radiogenic he production and transport in a sediment column with homogeneous fluid transport properties overall the in situ radiogenic he production due to the decay of u and th in the mineral phases of the sediments accounts for about 80 of the he accumulation at approx 190 m we observe a very high he concentration immediately below a large lithological unit characterised by strong deformations we speculate that this local enrichment is the result of the lower effective diffusivities in the pore space that relate to the abrupt depositional history of this deformed unit this particular lithological unit seems to act as a barrier that limits the transport of solutes in the pore space and hence might trap information on the past geochemical conditions in the pore water of lake van the dissolved concentrations of atmospheric noble gases in the pore waters of the icdp paleovan cores are used to geochemically reconstruct salinity on the time scale of 0 55 ka bp higher salinities in the pore water at a depth of about 20 m suggest a significantly lower lake level of lake van in the past

speleothem isotopic evidence of winter rainfall variability in northeast turkey between 77 and 6 ka an oxygen isotope record from a stalagmite that grew between 77 ka and 6 ka in northeast turkey contains both a strong precessional signal and sub orbital oscillations similar to those in greenland ice cores and chinese speleothem records of monsoon intensity fluid inclusion evidence of a negative shift in the isotopic composition of dripwater during the lateglacial supports interpretation of the isotope curve as an insolation forced record of changes in rainfall seasonality the high amplitude millennial scale fluctuations are caused by rapid changes in rainfall seasonality and or switching of moisture source areas both of which are associated with the stadial interstadial climatic oscillations linked to the changing modes of the north atlantic meridional overturning circulation moc winter rainfall maxima in northeast turkey coincide with interstadial conditions in greenland and with periods of intensified asian monsoon activity the isotopic shifts in the record are in antiphase with and are generally much larger in amplitude than published data from stalagmites in northwest turkey most likely because of differing moisture source areas carbon isotope ratios are probably kinetically enriched by partial degassing of seepage water in the epikarst but although often difficult to decypher particularly during marine isotope stage mis 2 broadly support the interpretations of the oxygen data

high resolution greenland ice core data show abrupt climate change happens in few years the last two abrupt warmings at the onset of our present warm interglacial period interrupted by the younger dryas cooling event were investigated at high temporal resolution from the north greenland ice core project ice core the deuterium excess a proxy of greenland precipitation moisture source switched mode within 1 to 3 years over these transitions and initiated a more gradual change over 50 years of the greenland air temperature as recorded by stable water isotopes the onsets of both abrupt greenland warmings were slightly preceded by decreasing greenland dust deposition reflecting the wetting of asian deserts a northern shift of the intertropical convergence zone could be the trigger of these abrupt shifts of northern hemisphere atmospheric circulation resulting in changes of 2 to 4 kelvin in greenland moisture source temperature from one year to the next

source mechanism of the 2000 november 15 lake van earthquake mw 5 6 in eastern turkey and its seismotectonic implications summary detailed source process of the 2000 november 15 lake van eastern turkey earthquake mw 5 6 was retrieved using the method of kikuchi kanamori for source inversion of complex body waveforms the event has been reported by usgs as a deep 67 km subcrustal earthquake resulting from a rupture on a normal fault beneath the bitlis suture zone where continental collision is in action between the arabian and eurasian plates however our source model based on the analysis of complex body waveforms suggests that the earthquake is a shallow crustal event comprised of two subevents on a predominantly reverse fault at depths of 12 5 and 15 km with a time interval of about 18 s the seismic moment of the second subevent mo 1 6 1017 nm strike 76 dip 55 and rake 120 is larger than the first subevent mo 1 0 1017 nm strike 87 dip 62 and rake 110 visual inspection of the strong ground motion records and waveform inversion analysis of the near field records from four broad band stations confirm the occurrence of the two subevents at shallow depths we examined whether or not the observed complex waveforms of the main shock can be modelled in terms of a single point source embedded at an intermediate depth and the result turned out to be further evidence for the multiple rupture the plausibility of the focal depths and mechanisms of the two subevents was also examined by retrieving the source parameters of 14 aftershocks from near field waveform data most of the aftershocks were relocated at depths around 15 km which agrees with the shallow main shock in addition the analysis of near field waveform data indicates subcrustal earthquake activity neither in the source region of the lake van earthquake nor in the turkey iran border region in the turkey iran border region an event on 1999 february 19 was reported to have taken place at a depth of 66 km usgs and 77 km isc which also conflicts with our focal depth 18 km determined through cmt inversion analysis of the broad band records at the station gni

climatically induced lake level changes at lake van turkey during the pleistocene holocene transition sediment core k10 from lake van eastern turkey provides a continuous varve record back to 14 570 calendar years b p before present 1950 the longest unbroken and non floating lake varve sequence yet described the underlying sediment is unvarved and hard changes in the aragonite calcite ratio the presence of protodolomite and magnesite in certain profile sections the annual record of the sedimentation rate the water content of the sediment the concentrations of organic carbon and opal and the texture of the sediments from this core provide a record of the lake level history the new chronology enabled us to redate the old pollen profile van zeist and woldring 1978a b and to establish an accurate timescale for the reconstructed lake level change carbon 14 dates show that the highest lake terrace corresponds to high lake level at around 19 000 years b p during the last glacial 70 m above its present level before 15 000 years b p the lake must have been completely dry marking a reduction of lake level by 500 m in maximum 4000 years beginning at 14 600 years b p and ending at 12 040 years b p the lake level recovered by 250 m to fall again during the next 1400 years by 10 600 years b p the lake began to rise and reached following another regression between 9000 and 8100 years b p the holocene highstand by about 7500 years b p dropping to today s level at about 3000 years b p

climatic conditions during marine oxygen isotope stage 6 in the eastern mediterranean region from the isotopic composition of speleothems of soreq cave israel at several times during marine oxygen isotope stage 6 the eastern mediterranean region was influenced by two extreme climatic systems the large ice sheet over northern europe and the wet tropics associated with african monsoons during this interval two major climatic events occurred in the region the sapropel s6 layer formed ca 176 ka in the eastern mediterranean basin owing to the increase in the african monsoon and another event although not large enough to form sapropel occurred ca 151 ka the isotopic composition of soreq cave speleothems seems to record these events as very low 18 o 13 c values dated as ca 178 and 152 ka the very low 18 o 13 c values of 6 and 11 to 12 respectively are typical of interglacial intervals but here they were recorded during a glacial interval such low peaks indicate that in this part of the eastern mediterranean region i e israel the rainfall amount increased dramatically moreover the isotopic record of the speleothems also shows that during the entire stage 6 although the climate was as cold as much of the last glacial the conditions were never as dry

the record of historic earthquakes in lake sediments of central switzerland deformation structures in lake sediments in central switzerland can be attributed to strong historic earthquakes the type and spatial distribution of the deformation structures reflect the historically documented macroseismic intensities thus providing a useful calibration tool for paleoseismic investigations in prehistoric lake sediments the swiss historical earthquake catalogue shows four moderate to strong earthquakes with moment magnitudes of mw 5 7 to mw 6 9 and epicentral intensities of i0 vii to i0 ix that affected the area of central switzerland during the last 1000 years these are the 1964 alpnach 1774 altdorf 1601 unterwalden and 1356 basel earthquakes in order to understand the effect of these earthquakes on lacustrine sediments four lakes in central switzerland sarner see lungerer see baldegger see and seelisberg seeli were investigated using high resolution seismic data and sediment cores the sediments consist of organicand carbonate rich clayey to sandy silts that display fine bedding on the centimeter to millimeter scale the sediments are dated by historic climate and environmental records 137 cs activity and radiocarbon ages deformation structures occur within distinct zones and include large scale slumps and rockfalls as well as small scale features like disturbed and contorted lamination and liquefaction structures these deformations are attributed to three of the abovementioned earthquakes the spatial distribution of deformation structures in the different lakes clearly reflects the historical macroseismic dataset lake sediments are only affected if they are situated within an area that underwent groundshaking not smaller than intensity vi to vii we estimate earthquake size by relating the epicentral distance of the farthest liquefaction structure to earthquake magnitude this relationship is in agreement with earthquake size estimations based on the historical dataset d 2004 elsevier b v all rights reserved

on the structure and origin of major glaciation cycles 2 the 100 000 year cycle climate over the past million years has been dominated by glaciation cycles with periods near 23 000 41 000 and 100 000 years in a linear version of the milankovitch theory the two shorter cycles can be explained as responses to insolation cycles driven by precession and obliquity but the 100 000 year radiation cycle arising from eccentricity variation is much too small in amplitude and too late in phase to produce the corresponding climate cycle by direct forcing we present phase observations showing that the geographic progression of local responses over the 100 000 year cycle is similar to the progression in the other two cycles implying that a similar set of internal climatic mechanisms operates in all three but the phase sequence in the 100 000 year cycle requires a source of climatic inertia having a time constant similar to 15 000 years much larger than the other cycles similar to 5 000 years our conceptual model identifies massive northern hemisphere ice sheets as this larger inertial source when these ice sheets forced by precession and obliquity exceed a critical size they cease responding as linear milankovitch slaves and drive atmospheric and oceanic responses that mimic the externally forced responses in our model the coupled system acts as a nonlinear amplifier that is particularly sensitive to eccentricity driven modulations in the 23 000 year sea level cycle during an interval when sea level is forced upward from a major low stand by a milankovitch response acting either alone or in combination with an internally driven higher frequency process ice sheets grounded on continental shelves become unstable mass wasting accelerates and the resulting deglaciation sets the phase of one wave in the train of 100 000 year oscillations whether a glacier or ice sheet influences the climate depends very much on the scale the interesting aspect is that an effect on the local climate can still make an ice mass grow larger and larger thereby gradually increasing its radius of influence

late holocene climates of the near east deduced from dead sea level variations and modern regional winter rainfall the dead sea is a terminal lake of one of the largest hydrological systems in the levant and may thus be viewed as a large rain gauge for the region variations of its level are indicative of the climate variations in the region here we present the decadal to centennialresolution holocene lake level curve of the dead sea then we determine the regional hydroclimatology that affected level variations to achieve this goal we compare modern natural lake level variations and instrumental rainfall records and quantify the hydrology relative to lake level rise fall or stability to quantify that relationship under natural conditions rainfall data pre dating the artificial dead sea level drop since the 1960s are used in this respect jerusalem station offers the longest uninterrupted pre 1960s rainfall record and jerusalem rains serve as an adequate proxy for the dead sea headwaters rainfall principal component analysis indicates that temporal variations of annual precipitation in all stations in israel north of the current 200 mm yr 1 average isohyet during 1940 1990 are largely synchronous and in phase 70 of the total variance explained by pc1 this station also represents well northern jordan and the area all the way to beirut lebanon especially during extreme drought and wet spells we a determine the modern and propose the past regional hydrology and eastern mediterranean em climatology that affected the severity and length of droughts wet spells associated with multiyear episodes of dead sea level falls rises and b determine that em cyclone tracks were different in average number and latitude in wet and dry years in jerusalem the mean composite sea level pressure and 500 mb height anomalies indicate that the potential causes for wet and dry episodes span the entire em and are rooted in the larger scale northern hemisphere atmospheric circulation we also identified remarkably close association within radiocarbon resolution between climatic changes in the levant reflected by level changes and culture shifts in this region

modern and holocene sublittoral ostracod assemblages crustacea from the caspian sea a unique brackish deep water environment abstract we present a reconnaissance study of sublittoral ostracods from a number of caspian sea core tops collected during a joint french russian scientific cruise in 1994 cores from between 13 and 875 m water depth the modern ostracods show little depth restriction and this reflects the hydrography of the caspian sea which maintains relatively constant conditions 5 c 13 salinity below 50 m throughout the year we also present the ostracod faunal record from a 10 m core of laminated sediments recovered from the central caspian basin at a water depth of 475 m which we believe shows repetitive quasi cyclic changes in bottom water conditions over approximately the last 14 15 000 years with a major change at about the late glacial to holocene transition the faunal record from this core illustrates the potential of these sediments for reconstructing environmental changes in the caspian region during the late quaternary to holocene the continuous occurrence of in situ benthic meiofauna throughout the core also indicates that the bottom water must have remained ventilated throughout this period although variability in the faunal assemblages may reflect long and short term changes in the strength of ventilation

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

muted climate variations in continental siberia during the mid pleistocene epoch the large difference in carbon and oxygen isotope data from the marine record between marine oxygen isotope stage 12 mis 12 and mis 11 spanning the interval between about 480 and 380 kyr ago has been interpreted as a transition between an extremely cold glacial period and an unusually warm interglacial period with consequences for global ice volume sea level and the global carbon cycle1 2 3 4 the extent of the change is intriguing because orbital forcing is predicted to have been relatively weak at that time5 here we analyse a continuous sediment record from lake baikal siberia which reveals a virtually continuous interglacial diatom assemblage a stable littoral benthic diatom assemblage and lithogenic sediments with interglacial characteristics for the period from mis 15a to mis 11 from about 580 to 380 kyr ago from these data we infer significantly weaker climate contrasts between mis 12 and 11 than during more recent glacial interglacial transitions in the late pleistocene epoch about 130 to 10 kyr ago for the period from mis 15a to mis 11 we also infer an apparent lack of extensive mountain glaciation

biochemical and ultrastructural evidence for the origin of whitings a biologically induced calcium carbonate precipitation mechanism we propose that bahamian whitings floating patches of lime mud are in part the result of biological precipitation of calcium carbonate induced by picoplankton and cellular components the cells may act as nucleation sites for crystallization from seawater supersaturated with caco3 our model represents a new hypothesis concerning bahamian whiting formation and is based on several lines of evidence biochemical data suggest that the macromolecules from carbonate suspended in bahama banks whitings are distinct from those found in the lime mud sediment producer penicillus and from bottom sediment direct ultrastructural evidence indicates that mineralization occurs on the surfaces of picoplankton cells and degrading organic cellular components the organic constituents include but are not restricted to whole and fragmented algal cells and composite structures 20 30 m in diameter the observed calcium carbonate crystals are distinct from skeletal debris because of the magnitude of the whiting phenomenon calculations of carbonate sediment production budgets should include the potential contribution of calcium carbonate produced by epicefular precipitation knowledge of carbonate mud genesis is critical to interpretation of ancient occurrences of lime mud as well as to understanding ancient and global carbon cycles

sedimentary evolution and environmental history of lake van turkey over the past 600 000 years the lithostratigraphic framework of lake van eastern turkey has been systematically analysed to document the sedimentary evolution and the environmental history of the lake during the past ca 600 000 years the lithostratigraphy and chemostratigraphy of a 219 m long drill core from lake van serve to separate global climate oscillations from local factors caused by tectonic and volcanic activity an age model was established based on the climatostratigraphic alignment of chemical and lithological signatures validated by 40ar 39ar ages the drilled sequence consists of ca 76 lacustrine carbonaceous clayey silt ca 2 fluvial deposits ca 17 volcaniclastic deposits and 5 gaps six lacustrine lithotypes were separated from the fluvial and event deposits such as volcaniclastics ca 300 layers and graded beds ca 375 layers and their depositional environments are documented these lithotypes are i graded beds frequently intercalated with varved clayey silts reflecting rising lake levels during the terminations ii varved clayey silts reflecting strong seasonality and an intralake oxic anoxic boundary for example lake level highstands during interglacials interstadials iii caco3 rich banded sediments which are representative of a lowering of the oxic anoxic boundary for example lake level decreases during glacial inceptions iv caco3 poor banded and mottled clayey silts reflecting an oxic anoxic boundary close to the sediment water interface for example lake level lowstands during glacials stadials v diatomaceous muds were deposited during the early beginning of the lake as a fresh water system and vi fluvial sands and gravels indicating the initial flooding of the lake basin the recurrence of lithologies i to iv follows the past five glacial interglacial cycles a 20 m thick disturbed unit reflects an interval of major tectonic activity in lake van at ca 414 ka bp although local environmental processes such as tectonic and volcanic activity influenced sedimentation the lithostratigraphic pattern and organic matter content clearly reflect past global climate changes making lake van an outstanding terrestrial archive of unprecedented sensitivity for the reconstruction of the regional climate over the last 600 000 years

a geological study of lake van eastern turkey lake van is a lake with a volume of 607 km3 and a maximum depth of 451 m in a tectonically active zone in eastern anatolia it may be divided into three physiographic provinces lacustrine shelf sublacustrine slope and lake basin the shelf is largely made up of submerged fluvial valleys and alluvial plains as evidenced by the local occurrence of karst like topography buried leveed river valleys and sediment wedges interpretable as relict deltas the shelf and basinal deposits are characterized by an alternating succession of well stratified and chaotically reflecting layers consisting of turbidites and slump deposits respectively this thick sequence of unconsolidated to consolidated sediments is underlain by a paleozoic metamorphic or upper cretaceous limestone basement

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

gradual onset of anoxia across the permian triassic boundary in svalbard norway the permian triassic extinction event is considered to be the most devastating environmental crisis of the phanerozoic with many coinciding factors involved the role of marine anoxia during the extinction is still poorly understood in this study a boreal permian triassic boundary ptb section from svalbard norway has been investigated with the aim of better understanding the timing and nature of local marine anoxia onset and extinction events across the ptb the section comprises the kapp starostin and vikinghogda formations 13corg values indicate the ptb is located within the lower part of the vikinghogda formation lag deposits at the top of the kapp starostin formation indicate a marine hiatus and ensuing transgression during the late permian shortly before the extinction event implying concurrence of major ecological changes and sea level rise pyrite framboid size distributions and total organic carbon toc were used to evaluate bottom water oxygen conditions and show that changes in bottom water redox conditions and extinction are clearly linked oxic to dysoxic bottom water conditions prevailed during deposition of kapp starostin formation sediments and changed to anoxic to euxinic conditions above the formation boundary the onset of anoxia is not abrupt but rather shows a gradual increase within the kapp starostin formation during the late permian the tipping point where bottom waters reach a long term state of anoxia to euxinia coincides with the final extinction event though changes in biotic assemblages at the top of the kapp starostin formation indicate a marine ecosystem crisis prior to this oxygen depletion in the boreal region as seen in our study section and correlating to greenland and arctic canada seems to be consistently more severe than in lower latitude settings

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

a 250 ka sedimentary record from a small karstic lake in the northern levant yammouneh lebanon paleoclimatic implications the levant influenced by both the mediterranean sea and the saharan arabian deserts is a key region for understanding climatic changes in response to glacial interglacial boundary conditions that have greatly affected regional hydrology here we present the first long term paleoenvironmental record from the northern levant presently much wetter than the southern levant our record derives from the multi proxy study of a sediment core 36 m long retrieved from the small intra mountainous tectonic basin of yammouneh lebanon which is mainly supplied by karstic springs sediments consist of a thick accumulation of brownish to greenish clayey silts interrupted by intervals of whitish marls composed of caco3 rich material the core chronology is based on radiometric dating 14c and u th and paleomagnetic techniques the sedimentary sequence spans approximately the last two glacial interglacial cycles 250 ka carbonate content is relatively high throughout the profile due to a perennial input of detrital calcite from the watershed but varies significantly the marls are mostly composed of authigenic and biogenic calcite and reflect lacustrine environments with high carbonate productivity during peaks of interglacial periods their occurrence suggests low physical erosion of the basin slopes which were covered by arboreal vegetation and intense karstic water circulation under warm and relatively wet conditions in agreement with pollen data the clayey silts are dominated by quartz and clay minerals and a few amounts of k feldspars and dolomite they are characterized by high concentration in magnetic particles and high relative concentrations of si al k and fe considered as strictly of detrital origin due to the carbonated nature of the watershed quartz and k feldspars are attributed to eolian origin from a distal source the clayey silt intervals generally suggest palustrine conditions with abrupt flows responsible for runoff derived material or subaerial environments and low local water availability in particular during the last glacial maximum high si al and k al ratios during interglacials are attributed to relatively high eolian dust contribution due to the decrease of local detrital inputs our study reveals significant differences between yammouneh and lake records from the dead sea basin southern levant the latter showing high low levels during glacial interglacial periods these hydrological differences might reflect either changes in the north south ns rainfall gradient in response to the development of the northern ice sheet and the southward migration of the westerly belt or local factors i e a decrease in efficient precipitation and water availability at yammouneh during the coldest glacial periods e g the last glacial maximum due to water storage by ice caps on the mount lebanon range and frozen soils in the yammouneh basin

impact of lake level change on deep water renewal and oxic conditions in deep saline lake van turkey 1 changes in the hydrological regime of the saline closed basin lake van a large deep lake in eastern turkey resulted in a lake level increase by about 2 m between 1988 and 1995 followed by a 1 5 m decrease until 2003 and a relatively constant lake level thereafter based on measurements of transient tracers sulfur hexafluoride cfc 12 3h 3he 4he ne dissolved oxygen light transmission conductivity temperature depth profiles and thermistor data we investigate the implications associated with lake level fluctuations for deep water renewal and oxygenation our data suggest that deep water renewal was significantly reduced in lake van between 1990 and 2005 this change in mixing conditions resulted in the formation of a more than 100 m thick anoxic deep water body below 325 m depth apparently the freshwater inflows responsible for the lake level rise between 1988 and 1995 decreased the salinity of the surface water sufficiently that the generation of density plumes during winter cooling was substantially reduced compared to that in the years before the lake level rise significant renewal and oxygenation of the deep water did not occur until at least 2005 although by 2003 the lake level was back to almost the same level as in 1988 this study suggests that short term changes in the hydrological regime resulting in lake level changes of a couple of meters can lead to significant and long lasting changes in deep water renewal and oxic conditions in deep saline lakes

evolution of colpan barrier and lagoon complex lake van turkey sedimentological and hydrological approach abstract the northeastern coast of the lake van eastern anatolia turkey is exposed to energetic waves inducing large sediment transport rates intense wave activity on coastal environment shows the shaping impact on the shoreline either erosional or depositional processes sedimentation is characterized by gravelly beaches spit formation and barrier lagoon complex colpan barrier and lagoon complex forming the subject of this study occurred in these swashed environmental conditions this study aims to introduce formation and evolution of the colpan barrier and lagoon complex and to assess the future development of the coastal area around the lake van characteristics of barrier sediments as shape size provenance sedimentary structures and palaeocurrent directions are determined with field investigations smooth flattened and rounded polygenetic sediments compose the barrier drifted to the shoreline with coastal processes as wave and longshore currents colpan barrier was created a lagoon completely isolated from lake van this wetland constitutes a habitat for some animals and plants with relatively dilute water than sodic lake van s water level fluctuation is an important element for the constructive and destructive processes for the barrier and lagoon complex

millennial scale variability during the last glacial the ice core record the oxygen isotope records from greenland ice cores show a very strong reproducible pattern of alternation between warm greenland interstadials gi and cold greenland stadials gs at millennial scale during the last glacial period here we summarise what is known about this variability from ice core records the typical cycle has a sawtooth pattern with a very rapid warming event occurring in a few decades a slow cooling trend and then a final fast cooling 25 such events have been numbered in the last glacial the recent gicc05 age scale provides the best available age scale that can be directly applied to this stratigraphy and we summarise the timing of the warming events and the length and strength of each event the greenland stratigraphy can be transferred to other records if we make assumptions about the contemporaneous nature of rapid events in different archives other parameters such as the snow accumulation rate and the concentration of terrestrial dust and sea salt recorded in the greenland cores also show a strong contrasting pattern between gi and gs methane concentrations are generally high during gi and lower during gs with the increase from gs to gi occurring within a century antarctic ice cores show a different pattern each gi has an antarctic counterpart but antarctica appears to warm while greenland is in a gs and cool during gi these changes are consistent with a mechanism involving ocean heat transport but the rapid nature of warmings poses a challenge for modellers while the rapid methane changes pose questions about the pattern of land biosphere emissions during the glacial that are also relevant for understanding glacial interglacial methane variability

injection of mantle type helium into lake van turkey the clue for quantifying deep water renewal helium neon and tritium concentrations have been measured to study long term vertical mixing and deep water renewal in lake van eastern turkey the largest soda lake on earth helium excesses were found in the water column of lake van although neon concentrations were close to air saturation the excesses of both isotopes are strictly correlated and increase with depth in the bottom water 4he supersaturation is about 20 and the corresponding 3he concentration is 2 5 times the air saturation value the mean excess 3he 4he ratio of 1 1 2 10 5 is slightly higher than the morb ratio found in lake nemrut a neighbouring volcanic crater lake in which a large input of mantle helium was detected mantle helium accounts for the majority of the helium excesses in lake van although part of the 3he excess is attributed to the presence of tritium a one dimensional lake model was used which describes tritium input vertical mixing and gas exchange to reconstruct the evolution of the helium isotopes and the tritium as a conclusion the model based on the measured 3he and 4he profiles shows that 1 the vertical exchange of deep water occurs within 1 2 yr 2 the flux of mantle helium into the lake averaged over the total cross section of lake van is 0 23 0 35 cm3 stp m 2 yr 1 2 3 1011 atoms m 2 s 1 the present estimate of the global mantle helium flux averaged over the total surface area of the earth is 3 9 109 atoms m 2 s 1 the flux into lake van would account for at least 0 04 0 06 of this

beach deposits of mis 5e high sea stand as indicators for tectonic stability of the carmel coastal plain israel abstract ten beach deposits mainly beachrock on the carmel coastal plain northern israel are discussed six are reported for the first time the deposits are situated within or close to the following seasonal stream locally termed nahal channels nahal ahuza amiram ovadia galim megadim bir ibdawiya me arot and kebara the morphology and lithology of most of the deposits are similar their uppermost altitude varies from 0 to 9 m above the present sea level most of the deposits are composed mainly of fine quartz sand and marine mollusk shells carbonate cemented the dominant mollusk families are glycymerididae cardiidae and donacidae most of the beach deposits are situated between cemented aeolian sandstones locally termed kurkar layers on the carmel coast ridge in the nahal ahuza deposit a marine gastropod lentigo latus an index fossil for the mis 5e high sea stand in the mediterranean area was discovered according to lithology and chronostratigraphy the presence of lentigo latus th u aar and rtl dating and flint artifacts the beach deposits were related to the last interglacial maximum about 125 ka bp i e the mis 5e high sea stand these beach deposits are used to identify the palaeo sea levels and coastlines and to study the tectonics along the carmel coastal plain by comparing the elevations and characteristics of the beach deposits to known mis 5e deposits elsewhere and by analyzing archaeological data it is concluded that during the last 125 ka the maximum possible vertical displacement was less than 48 mm ka and the carmel coastal plain was relatively tectonically stable

the last 1 35 million years at tenaghi philippon revised chronostratigraphy and long term vegetation trends abstract in addition to being of interest to ancient greek and roman historians the site of philippi ne greece has long been noted in quaternary circles for providing the longest continuous european pollen record spanning the last one million years here the original age model is re evaluated and a new marine terrestrial correlation is proposed an astronomical calibration procedure based on a correspondence between changes in certain vegetation elements and march and june perihelion configurations suggests that the base of the sequence extends back to 1 35 million years ago the revised chronological framework for the tenaghi philippon sequence provides an opportunity to examine the long term behaviour of individual taxa and vegetation trends within the context of global climate changes comparisons reveal a close correspondence between the terrestrial and marine records in terms of orbital and suborbital variability however joint time frequency analysis of the arboreal pollen record shows that the obliquity and eccentricity precession signals persist into the 100 kyr and 41 kyr worlds respectively suggesting the operation of additional climate mechanisms that are independent of high latitude glacial interglacial effects unlike ice core and marine sequences no change in the magnitude of interglacial tree population expansions is observed after the mid brunhes event instead the tenaghi philippon record suggests a major shift in the vegetational composition of interglacials after mis 16 with the establishment of forests of reduced diversity and a modern appearance

soft sediment deformation structures interpreted as seismites in lacustrine sediments of the prebetic zone se spain and their potential use as indicators of earthquake magnitudes during the late miocene lacustrine formations of late miocene age in the prebetic area se spain show several types of deformational structures that are interpreted as seismites they are present in both marginal and deep lacustrine facies seismites formed in marginal lake environments comprise sand dikes pillows and intruded and fractured gravels in deep lacustrine facies the seismites are represented by pseudonodules mushroom like silts protruding into laminites mixed layers disturbed varved lamination and loop bedding the measured orientations of these structures are consistent with the orientations of the main faults limiting the basins showing that their origin is clearly related to the tectonic stress field that prevailed in the region during the late miocene the magnitudes of the earthquakes that deformed the sediments have been estimated after published data from both ancient and recent lake deposits accumulated in tectonic active regions elsewhere a rank of earthquake magnitudes with two end members i e the lowest magnitudes recorded by loop bedding in laminites and the highest magnitudes represented by intruded and fractured gravels is proposed

unusual distributions of long chain alkenones and tetrahymanol from the highly alkaline lake van turkey long chain c37 to c40 alkenones with di tri and tetra unsaturation are very abundant in sediment trap material and holocene to late pleistocene core samples from the earth s largest soda lake lake van turkey thus the known distribution range of these typical biomarkers for haptophyte microalgae is extended to highly alkaline environments the observed unsaturation patterns differ strikingly from those found in open marine haptophytes and sediments by an enhanced relative abundance of the tetra unsaturated compounds especially the c37 4 methyl ketone their preponderance is suggested to be a facies marker pattern for lacustrine and marginal marine areas of sedimentation using published u37k calibrations no reliable absolute temperatures were obtained for the lake van samples accordingly marine sea surface temperature determinations based on long chain alkenones should be applied with caution when a contribution of these compounds from coastal or nonmarine sources can not be excluded the presence of tetrahymanol and gammacer 3 one in the lake van materials is attributed to organic matter contributions of ciliates the relative abundance of long chain alkenones and of tetrahymanol gammacer 3 one is considered to reflect changes in the environmental conditions in particular in the hydrological setting we suggest that times of pronounced stagnation are recognised by very high tetrahymanol gammacer 3 one concentrations together with drastically increased stanol stenol ratios and intervals of enhanced convection or of high freshwater input are characterised by high alkenone contributions

mineral magnetic study of late quaternary south caspian sea sediments palaeoenvironmental implications summary magnetic properties of sediments from a core 10 m long in the southern basin of the caspian sea have been investigated varying concentrations of greigite fe 3 s 4 dominate the magnetic fraction in late pleistocene sediments the synsedimentary formation of greigite indicates that the late pleistocene caspian sea was a brackish or fresh water poorly ventilated basin and suggests a water level higher than at the present the variation in magnetic parameters with the detrital magnetite bearing fraction remaining constant is interpreted in terms of greigite grain size variation and related to the slight variation in water salinity the holocene sediments are characterized by detrital magnetite this indicates better ventilation of the basin and suggests lower water levels than in the late pleistocene the gradual change in magnetic properties of the sediments between 90 and 60 cm depth with decreasing quantities of greigite indicates stepwise establishment of oxic conditions in the holocene

paleovan international continental scientific drilling program icdp site survey results and perspectives lake van is the fourth largest terminal lake in the world volume 607 km 3 area 3570 km 2 maximum depth 460 m extending for 130 km wsw ene on the eastern anatolian high plateau turkey the sedimentary record of lake van partly laminated has the potential to obtain a long and continuous continental sequence that covers several glacial interglacial cycles ca 500 kyr therefore lake van is a key site within the international continental scientific drilling program icdp for the investigation of the quaternary climate evolution in the near east paleovan as preparation for an icdp drilling campaign a site survey was carried out during the past years we collected 50 seismic profiles with a total length of similar to 850 km to identify continuous undisturbed sedimentary sequences for potential icdp locations based on the seismic results we cored 10 different locations to water depths of up to 420 m multidisciplinary scientific work at positions of a proposed icdp drill site included measurements of magnetic susceptibility physical properties stable isotopes xrf scans and pollen and spores this core extends back to the last glacial maximum lgm a more extended record than all the other lake van cores obtained to date both coring and seismic data do not show any indication that the deepest part of the lake tatvan basin ahlat ridge was dry or almost dry during past times these results show potential for obtaining a continuous undisturbed long continental palaeoclimate record in addition this paper discusses the potential of paleovan to establish new results on the dynamics of lake level fluctuations noble gas concentration in pore water of the lake sediment history of volcanism and volcanic activities based on tephrostratigraphy and paleoseismic and earthquake activities c 2009 elsevier ltd all rights reserved