the background of transitions in microblade industries in hokkaido northern japan abstract the purpose of this paper is to discuss the archaeological transitions among microblade industries in hokkaido and to propose some possible relations between human activities and natural environment hokkaido is situated in the north of the japanese archipelago and the microblade industries in this region lasted approximately from 24 000 to 13 000 cal bp corresponding to the climatic changes of the mis2 last glacial maximum lgm cold2 and mis2 late glacial warm lg warm the primary purpose of this paper is to describe the whole picture of transitions observed in microblade industries through a series of examinations on the size of microblades maintenance of burins and the stone tool classes results suggest that the following changes in hunting related stone tools were occurred during the lg warm 1 miniaturization in the part of spears microblades 2 high frequency in burin maintenance and 3 appearance of the new hunting weapon i e projectile points and axes then a preliminary discussion on the possible relations between human activities and the natural environment including some significant climate changes is made referring to the recent studies on the analyses of charred deposits on pottery from the taisho 3 site which belongs to lg warm given the fact that the alterations in the environment and human activities were coincident i propose the hypothesis that the transitions in microblade industries in hokkaido was an outcome of human adaptation to the fluctuation in accessible natural resources caused by the globally occurred warming trend

quantifying climatic change through the last glacial interglacial transition based on lake isotope palaeohydrology from central turkey questions remain as to the nature of climatic change through the last glacial interglacial transition in the eastern mediterranean region particularly the relative contribution of evaporation and precipitation to regional water balance here changes in oxygen isotope values through this time period from eski acigol a crater lake in central turkey are investigated using hydrological and isotope mass balance models these allow changes in evaporation and precipitation to be quantified and their relative importance evaluated we show that it is the volumetric flux rate of water passing through the lake system and not the precipitation to evaporation ratio per se which controlled the stable isotope record in eski acigol early holocene precipitation is shown to be much greater than that during both the latter part of the last glaciation and the present day we test these calculated values against other records in the same region firstly with other lake records in anatolia the konya basin and lake van and secondly with isotope inferred palaeo precipitation data from soreq cave in israel this reveals a contrast between pre and post lgm precipitation values in turkey wetter and drier respectively and also suggests that during the last glacial interglacial transition there was a more marked precipitation gradient than at present between northern interior and southern coastal parts of the eastern mediterranean region

a study of oxygen isotopic fractionation during bio induced calcite precipitation in eutrophic baldeggersee switzerland in order to better understand environmental factors controlling oxygen isotope shifts in autochthonous lacustrine carbonate sequences we undertook an extensive one year study march 1995 to february 1996 of water column chemistry and daily sediment trap material from a small lake in central switzerland comparisons between calculated equilibrium isotope values using the fractionation equation of friedman and o neil 1977 and measured oxygen isotope ratios of calcite in the sediment traps reveal that oxygen isotopic values of autochthonous calcite 18o are in isotopic equilibrium with ambient water during most of the spring and summer when the majority of the calcite precipitates in contrast small amounts of calcite precipitated in early spring and again in late autumn are isotopically depleted in 18o relative to the calculated equilibrium values by as much as 0 8 this seasonally occurring apparent isotopic nonequilibrium is associated with times of high phosphorous concentrations elevated ph 8 6 and increased co32 50 mol l in the surface waters the resulting weighted average 18o value for the studied period is 9 6 compared with a calculated equilibrium 18o value of 9 4 these data convincingly demonstrate that 18o of calcite are for the most part a very reliable proxy for temperature and 18o of the water

fractal density modeling of crustal heterogeneity from the ktb deep hole fractal or multifractal concepts have significantly enlightened our understanding of crustal heterogeneity much attention has focused on 1 f scaling natures of physico chemical heterogeneity of earth crust from fractal increment perspective in this study fractal density model from fractal clustering point of view is used to characterize the scaling behaviors of heterogeneous sources recorded at german ktb main hole and of special contribution is the local and global multifractal analysis revisited by using haar wavelet transform hwt fractal density modeling of mass accumulation generalizes the unit of rock density from integer e g g cm3 to real numbers e g g cm so that crustal heterogeneities with respect to source accumulation are quantified by singularity strength of fractal density in dimensional space from that perspective we found that the bulk densities of metamorphic rocks exhibit fractal properties but have a weak multifractality decreasing with the depth the multiscaling natures of chemical logs also have been evidenced and the observed distinct fractal laws for mineral contents are related to their different geochemical behaviors within complex lithological context accordingly scaling distributions of mineral contents have been recognized as a main contributor to the multifractal natures of heterogeneous density for low porosity crystalline rocks this finally allows us to use de wijs cascade process to explain the mechanism of fractal density in practice the proposed local singularity analysis based on hwt is suggested as an attractive high pass filtering to amplify weak signatures of well logs as well as to delineate micro lithological changes

heterogeneity spectrum and scale anisotropy in the upper crust revealed by the german continental deep drilling ktb holes crustal heterogeneities and their statistical characteristics bear important information about the dynamic processes and evolution of the crust the velocity well log data from the german continental deep drilling project ktb offer a rare opportunity to measure directly the properties of crustal heterogeneities in this study we first estimated the power spectrum of crustal heterogeneities from the p velocity well logs of the two holes for the first time a power law spectrum of crustal heterogeneities was directly observed in the spatial wavelength range from a few meters to a few kilometers the slope of the vertical 1d power spectrum of the random velocity perturbations is about 1 1 corresponding to a flicker noise random medium the scale anisotropy ratio aspect ratio and the horizontal spectral slope of crustal heterogeneities were also estimated by cross correlation analysis between these two holes to be about 1 8 and 2 0 respectively

multiscaling nature of sonic velocities and lithology in the upper crystalline crust evidence from the ktb main borehole the observed scaling of sonic logs is generally described using a monofractal model fractional brownian motion with hurst exponent typically between 0 1 and 0 2 or fractional levy motion even though such a description recognizes the existence of the self similarity of the logs it offers only a limited account of the actual symmetry as it misses the displayed heterogeneous fractality intermittency of the velocity increments is here observed and calls for the use of a multifractal description we quantify such a multifractality in the case of the p wave sonic log recorded at the ktb main borehole we also show that the associated lithology inferred from the gamma log has a multifractal distribution as well though characterized by a stronger intermittency it can be expected that the multifractality of the sonic log is partially induced by the lithology though the observed discrepancy in the degree of intermittency between the two logs indicates that the scaling symmetry of the seismic velocity is probably due to many different contributions such statistics for both sonic and gamma logs have important implications on our understanding of wave propagation and rock strength and permeability in the crystalline crust as they show the crust to be more heterogeneous than is usually modeled

abiotically formed primary dolomite in the mid eocene lacustrine succession at gebel el goza el hamra ne egypt an approach to the role of smectitic clays abstract this study discusses the role of smectitic clays in the formation of an abiotic physio chemical primary dolomite within an evaporative alkaline saline marginal lake system in the absence of carbonate precursor and microbes the present work has been achieved in terms of textural mineralogical and geochemical characteristics of dolostones in the mid eocene bartonian lacustrine succession cropping out at gebel el goza el hamra shabrawet area ne egypt this lacustrine succession is 15 16 m thick and made up of alternating horizontal beds of dolostone marlstone and mudrock that show some pedogenic and subaerial exposure features the dolostones are composed mainly of dolomite 60 90 smectite 20 30 and quartz grains 5 10 the dolomite comprises fine crystalline rhombs to micro spherical crystals with no obvious relics of microbial activity and or carbonate precursor it is ordered nearly stoichiometric with 46 50 mole of mgco 3 and has 18 o and 13 c values ranging from 0 44 to 2 96 vpdb and 0 93 to 8 95 vpdb respectively the smectite occurs as thin mats that are commonly intergrown and associated with dolomite mineralogical textural and stable isotopic results of the dolomite indicated that the dolomite was formed as an abiotic primary precipitate in alkaline saline lacustrine systems in this respect the gel like highly viscous smectitic medium plus progressive co 2 degassing elevated evaporation low sedimentation rate low sulphates level and alkaline soil solution lowered the kinetic barriers of dolomite precipitation from solution and promoted the incorporation of mg 2 in the structure of dolomite consequently the presence of smectitic clays in evaporative saline lakes is significant for dolomite formation because they can generate a gel like highly viscous medium and provide mg 2 that can facilitate the physcio chemical precipitation of primary dolomite from solution at ambient temperatures however more work is needed to better characterize the role of clays during dolomite formation in alkaline lacustrine environments at ambient temperatures

deep structure of the crust along the fennoscandia sarmatia junction zone central belarus results of a geophysical geological integration abstract the eurobridge 96 seismic refraction and wide angle reflection profile in belarus crosses the 2 0 1 9 ga palaeoproterozoic central belarus belt cb subdivided by ne trending minsk fault into the northwestern nwcb and southeastern secb sub terranes differing in their styles of tectonothermal evolution the first interpretation of the eurobridge 96 profile however did not indicate any difference between the nwcb and secb and revealed a high velocity zone beneath the secb with a p wave velocity of 6 6 km s at a depth of 6 km which does not correlate with any pronounced positive bouguer anomaly we present a detailed analysis of the seismic and gravity data obtained along the eurobridge 96 profile complemented with petrological and petrophysical observations on the main rock types of the cb our integrated interpretation shows that the dip orientation of the main reflectors and the p wave velocity and density are different in the nwcb and secb the minsk fault zone is distinguished as an area of relatively high velocities 6 2 km s in the upper crust increased reflectivity in the middle crust se of the minsk fault may be explained by a laminated structure composed of alternating tectonically deformed amphibolite facies and granulite facies rocks that produce a certain seismic anisotropy this seismic anisotropy is proposed as an alternative explanation for the high p wave velocity in the middle crust beneath the secb that does not result in any corresponding positive gravity anomaly the laminated structure beneath the secb might be formed during the uplift of the nwcb and juxtaposition of the nwcb and secb

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

compositional and metamorphic controls on velocity and reflectivity in the continental crust an example from the grenville province of eastern quebec we present velocity and density data for a suite of gabbros and metagabbros over a range of metamorphic grades from subgreenschist to the eclogite facies most of these rocks have a mesocratic protolith with overlapping bulk chemistry ranges providing an opportunity to investigate the systematics of mineralogy and physical properties across a wide range of metamorphic grades with minimal compositional variation in addition more mafic gabbros in the eclogite facies were also investigated in order to take into account variations in the extent of transformation of gabbro to eclogite controlled by bulk chemistry the physical properties data are used as the basis for a first order crustal model composed of granitic anorthositic and gabbroic components the objective of constructing the crustal model is to evaluate the relative contribution of compositional variation and metamorphism to the velocity density and reflectivity structure of the continental crust the model suggests that in the upper crust if fracture porosity is neglected composition dominates the velocity and density structure while in the middle and lower crust composition and metamorphism play equally important roles simulations designed to predict potential reflection coefficient size distributions for the various bulk chemistries and mineralogies in the crustal model indicate step increases in the potential for large reflection coefficients that are dominantly controlled by metamorphic grade step increases in reflectivity are predicted between the lower and upper amphibolite facies and between incompletely and completely eclogitized metagabbros in the eclogite facies we also consider several alternative mixing models which account for the effects of one of the three lithologic components occurring as isolated bodies rather than perfectly mixed with the other two components these models indicate a reduction of the potential for large reflection coefficients by as much as 50 emphasizing the importance of the degree of mixing for crustal reflectivity

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

widespread submarine tephras around japan petrographic and chemical properties abstract in deep sea sediments around the japanese islands tephra layers are frequently recognized and some tephras can be identified by petrographic and chemical features and correlated to source volcanoes of both japan and korea most tephras distributed over more than several hundred kilometers from the source volcanoes were presumably carried away by the dominant westerly wind six characteristic marker tephras in deep sea sediments can be identified and correlated according to their distribution and grain size petrography and chemistry they play an important role in compiling the late quaternary chronology of the deep sea sediments distributed around the japanese islands petrographic and geochemical studies reveal that the refractive index of volcanic glass shards in tephras is controlled by the amount of total transition metal oxides rather than the amount of sio 2 we propose a new equation relating refractive index to glass shard chemistry

late quaternary paleoclimate in the eastern mediterranean region from stable isotope analysis of speleothems at soreq cave israel abstract the eastern mediterranean continental paleoclimate during the past 25 000 years was determined by a high resolution petrographic stable isotopic and age study of speleothems from soreq cave israel 18o 13c trends indicate that all speleothems older than 7000 yr formed under conditions that differ from those of today the period from 25 000 to 17 000 yr b p was characterized by the highest 18o and 13c values which indicate deposition at temperatures of 12 16 c annual rainfall of 300 450 mm and vegetation typical of a mixed c3 c4type from 17 000 to 10 000 yr b p deglaciation in northern europe 18o values dropped progressively correlative with warming 2 3 c and a gradual increase in precipitation a simultaneous decrease in 13c gives a range expected for c3 type vegetation this period also shows significant 18o and 13c spikes which are correlatable with global events e g heinrich events and the younger dryas stade the speleothems that grew between 10 000 and 7000 yr b p have a unique petrography showing irregular thin laminae of various colors and much detritus they have the lowest 18o corresponding to 1000 mm rain coupled with the highest 13c caused by flooding events which stripped the soil cover from 7000 to 1000 yr b p conditions became closer to those of today this study demonstrates that global events which were recognized in northern europe and north africa are also evident in the eastern mediterranean and are reflected principally by large changes in the rainfall rate

modern and early middle holocene shells of the freshwater mollusc unio from catalhoyuk in the konya basin turkey preliminary palaeoclimatic implications from molluscan isotope data carbon and oxygen isotope ratios in the shells of the freshwater unio mollusc yield information on the isotopic composition of the water in which the shell was formed which in turn relates to climatic conditions prevailing during the bivalves life span here we analysed shells from one modern unio from a modern lake shore in anatolia and 4 subfossil unio shells from catalhoyuk dated between 7200 bc and 5000 bc neolithic and chalcolithic periods sequential carbon and oxygen isotope analysis along the surface of the shells provides information on seasonal or shorter term variability of lake waters during the lifetime of the organisms 18o values of the modern shell are consistent with it being collected from a dammed portion of the seyhan river that does not undergo intensive summer evaporation this is in contrast to many of the surface water bodies in anatolia which suffer extensive evaporation in the arid summers 18o values of the subfossil shells from the catalhoyuk middens indicate that the bivalves came from lakes which evaporated extensively during the summer months but were replenished by high winter rainfall suggesting that the subfossil shells lived in relatively small lakes or ponds stable isotope analysis along the growth of freshwater bivalves is one of the few methods for investigating seasonal water fluctuations in the past these results may alter current interpretations on the environment of catalhoyuk during the neolithic although more work is needed to confirm these initial findings

the climate in europe during the eemian a multi method approach using pollen data the last interglacial period the eemian offers a testbed for comparing climate evolution throughout an interglacial with the current warm period we present here results from climatic reconstructions from 17 sites distributed across the european continent allowing an assessment of trends and regional averages of climate changes during this period we use a multi method approach to allow for an improved assessment of the uncertainties involved in the reconstruction in addition the method takes into account the errors associated with the age model the resulting uncertainties are large but allow a more robust assessment of the reconstructed climatic variations than in previous studies the results show a traditional three part eemian with an early optimum followed by slight cooling and eventually a sharp drop in both temperatures and precipitation this sequence is however restricted to the north as this latter change is not observed in the south where temperatures remain stable for longer these variations led to marked variation in the latitudinal temperature gradient during the eemian the difference between the two regions is also noticeable in the magnitude of changes with greater variations in the north than the south some evidence is found for changes in lapse rates however a greater number of sites is needed to confirm this

climate and vegetation in hokkaido northern japan since the lgm pollen records from core gh02 1030 off tokachi in the northwestern pacific abstract vegetation and climate since the lgm in eastern hokkaido were investigated based on a pollen record from marine core gh02 1030 from off tokachi in the northwestern pacific we also examined pollen spectra in surface samples from sakhalin to compare and understand the climatic conditions of hokkaido during the last glacial period vegetation in the tokachi region in the lgm 22 17 ka was an open boreal forest dominated by picea and larix during the last deglaciation 17 10 ka vegetation was characterized by abundant betula in the kenbuchi basin central hokkaido a remarkable increase of larix and pinus occurred in the lgm and the last deglaciation which was assigned as the kenbuchi stadial comparison of climatic data between the core gh02 1030 and that of kenbuchi basin demonstrates that variations in temperature and precipitation were larger in inland hokkaido than in the maritime area of the pacific coast during the lgm in the tokachi region the august mean temperature was about 5 c lower and annual precipitation was about 40 lower than today in the kenbuchi basin central hokkaido the august mean temperature was about 8 c lower and annual precipitation was half that of today during the last deglaciation august mean temperatures were about 3 c lower and annual precipitation was about 30 lower than today in the tokachi region in the kenbuchi basin august mean temperatures were about 5 8 c lower and annual precipitation was about 40 60 lower than today cold ocean water and a strengthened summer monsoon after 15 ka may have resulted in the formation of advection fogs reduced summer temperatures and a decrease in the seasonal temperature difference in the tokachi district which established favorable maritime conditions for betula forests

multifractal characteristics of natural fracture apertures using information acquired from microscanner logs in horizontal boreholes fracture apertures are shown to be characterized by multifractal scaling a representative f spectrum can be modeled using a multiplicative cascade based on a two scale cantor set the resulting cascade can be used to simulate fracture aperture distributions at any scale when compared to well data the simulations show good agreement with aperture sizes and reproduce the clustering commonly recognized in fracture networks

production and cycling of natural microbial exopolymers eps within a marine stromatolite extracellular polymeric secretions eps that are produced by cyanobacteria represent potential structuring agents in the formation of marine stromatolites the abundance production and degradation of eps in the upper layers of a microbial mat forming shallow subtidal stromatolites at highborne cay bahamas were determined using 14 c tracer experiments and were integrated with measurements of other microbial community parameters the upper regions of a type 2 reid r p visscher p t decho a w stolz j bebout b macintyre i g dupraz c pinckney j paerl h prufert bebout l steppe t des marais d 2000 the role of microbes in accretion lamination and early lithification of modern marine stromatolites nature london 406 989 992 stromatolite mat exhibited a distinct layering of alternating bgreenq cyanobacteria rich layers layers 1 and 3 and bwhiteq layers layers 2 and 4 and the natural abundance of eps varied significantly depending on the mat layer the highest eps abundance occurred in layer 2 the production of new eps as estimated by the incorporation of 14 c bicarbonate into eps occurred in all layers examined with the highest production in layer 1 and during periods of photosynthesis i e daylight hours a large pool i e up to 49 of the total 14 cbicarbonate uptake was released as low molecular weight mw dissolved organic carbon doc this doc was rapidly mineralized to co2 by heterotrophic bacteria eps degradation as determined by the conversion of 14 c eps to 14 co2 was slowest in layer 2 results of slurry experiments examining o2 uptake following additions of organic substrates including eps supported this degradation trend and further demonstrated selective utilization by heterotrophs of specific monomers such as acetate ethanol and uronic acids results indicated that natural eps may be rapidly transformed post secretion by heterotrophic degradation specifically by sulfate reducing bacteria to a more refractory remnant polymer that is relatively slow to accumulate a mass balance analysis suggested that a layer specific pattern in eps and low mw doc turnover may contribute to major carbonate precipitation events within stromatolites our findings represent the first estimate of eps

micrometer scale porosity as a biosignature in carbonate crusts we formed calcite crusts in the presence and absence of the heterotrophic bacterium desulfovibrio desulfuricans strain g20 to investigate microbial morphological signatures in fast accreting carbonate precipitates submicrometer to micrometer sized pores micropores were present and ubiquitous in the g20 crusts but absent in abiotically precipitated crusts bacterial micropores resemble inclusions under transmitted light but have distinct size biological shapes and patterns swirling or dendritic and are distributed differently from common fluid inclusions we observed similar porosity in both modern and ancient carbonate crusts of putative biotic origin our experiments support the microbial origin of micropores and help define specific criteria whereby to recognize these features as biosignatures in the rock record

lacustrine stromatolites as multi scale recorders of climate change insights from the miocene ebro basin sedimentological 13c and 18o data from stromatolites in a lower and middle miocene sequence from the ebro basin n spain are used to assess the potential of ancient lacustrine stromatolite lamination as an archive of palaeoenvironmental and palaeoclimatic change the isotopic evolution through the studied sequence supports a general trend toward less saline conditions with time stromatolites and muddy grainy laminated limestones developed in lake water that underwent little renewal compared with other carbonate facies the palaeoclimatic value of the stable isotope changes and concurrent textural variations in calcite stromatolite lamination is studied at different orders of cyclicity stromatolite lamination consists of simple laminae dark dense light dense and light porous grouped into alternating composite light and dark laminae 13c and 18o analyses in consecutive composite laminae bulk sampling yielded a cyclic pattern that mimics textural variations light laminae with lower 13c and 18o values reflect higher precipitation evaporation ratio p e and more influence of biogenic 12c dark laminae with higher 13c and 18o values reflect drier conditions more complete atmospheric co2 exchange with water and photosynthetic 12co2 uptake textural features of laminae support these results the dark laminae are related to higher calcite saturation in lake water during drier periods isotopic values from high resolution sampling through a 2 1 cm thick stromatolite reveal palaeoclimate variations at different temporal scales isotopic variation in 3rd order cyclicity of alternating light dark simple laminae is recording seasonal p e variations light and dark composite laminae 2nd order cyclicity correspond to pluriannual dominantly humid or dry conditions respectively a gradual succession from light to dark composite laminae forms the 1st order cycles driven by decreasing p e through longer pluriannual periods resulting in lake level lowering the stromatolites are thus recording lake level changes of centennial to millennial scale

stromatolites in walker lake nevada great basin usa record climate and lake level changes 35 000 years ago abstract walker lake is a closed basin remnant of the large pleistocene glacial lake lahontan system that has experienced multiple high amplitude 100 200 m changes in water level over the past 40 000 years in response to changes in climate a laminated carbonate stromatolite composed of varying proportions of calcite fans and micrite was collected from a paleoshoreline located at approximately 58 m above present lake level radiocarbon dating revealed that the stromatolite spans approximately 2000 years of growth from 35 227 to 33 727 calibrated years before present ybp a time period during which paleolake level is not well constrained distinct laminae were drilled along the growth axis and the resulting powders were collected for clumped isotope analyses to generate formation temperatures lake water temperatures during stromatolite formation from which 18 o water was calculated results indicate that the stromatolite experienced an initial increase in temperature and water 18 o values followed by a decrease in both during the course of accretion the resulting temperature and isotopic data were input into a rayleigh distillation model for lakewater evaporation in order to estimate the magnitude of lake level and volume fluctuations over the course of accretion modeling results reveal a lake level decrease between 8 1 and 15 6 m followed by an increase of between 4 3 and 8 8 m during the course of stromatolite growth the results of this study indicate that walker lake experienced significant lake volume change over the course of 2000 years perhaps as a response to precipitation changes driven by fluctuations in the polar jet stream and accompanying changes in regional climate and or evaporation induced changes in lake level these results add to a growing body of research indicating that stromatolites and other lacustrine tufas represent a detailed and extensive terrestrial archive that can potentially be used to reconstruct the timing and magnitude of climate change

epipalaeolithic settlement dynamics in southwest asia new radiocarbon evidence from the azraq basin a series of radiocarbon dates from two epipalaeolithic sites kharaneh iv and ayn qasiyya in the azraq basin of eastern jordan provide a new perspective on the chronology and settlement patterns of this part of southwest asia during the late pleistocene we discuss the implications to our understanding of the chronology of late pleistocene lithic industries particularly in regard to current hypotheses for the abandonment of eastern jordan s mega sites kharaneh iv and jilat 6 modelling a series of accelerator mass spectrometry dates from kharaneh iv indicates a much shorter span of occupation for the site than previously assumed by the size and density of its deposits given the high density of material accumulated over a relatively short time span we show that kharaneh iv was an aggregation site occupied intensively by a significant number of people providing new perspectives on the east jordanian phenomenon of epipalaeolithic mega sites copyright 2013 john wiley sons ltd

triggering of seismicity at short timescales following californian earthquakes 1 a method for measuring seismicity rate changes caused by the occurrence of major earthquakes in the surrounding crust is proposed it is based on a nonstationary poisson modeling of earthquake activity an estimate of the seismicity rate change and a probability measure of seismicity triggering following a large shock are derived and the removal of the influence of independent aftershock sequences of other nearby previous earthquakes is attempted without using more traditional declustering techniques the seismicity rate change estimator is corrected for its natural bias in favor of positive changes at short timescales that has so far strongly hindered measures of seismicity quiescences three californian earthquakes are examined using this method the 1989 m7 1 loma prieta the 1992 m7 3 landers and the 1994 m6 7 northridge earthquakes positive triggering is very commonly observed as expected but quiescence is however more seldomly obtained for timescales up to 100 days after the main shock this relative absence of quiescence as compared to typical predictions of coulomb modeling for example is also independently observed through direct correlation analyses of californian seismicity the possibility that the stresses caused by the main shock are spatially highly variable may explain these observations

nature and origin of upper crustal seismic velocity fluctuations and associated scaling properties combined stochastic analyses of ktb velocity and lithology logs the main borehole of the german continental deep drilling program ktb extends over 9000 m into a crystalline upper crust consisting primarily of interlayered gneiss and metabasite we present a joint analysis of the velocity and lithology logs in an effort to extract the lithology component of the velocity log covariance analysis of lithology log approximated as a binary series indicates that it may originate from the superposition of two brownian stochastic processes fractal dimension 1 5 with characteristic scales of 2800 m and 150 m respectively covariance analysis of the velocity fluctuations provides evidence for the superposition of four stochastic process with distinct characteristic scales the largest two scales are identical to those derived from the lithology confirming that these scales of velocity heterogeneity are caused by lithology variations the third characteristic scale 20 m also a brownian process is probably related to fracturing based on correlation with the resistivity log the superposition of these three brownian processes closely mimics the commonly observed 1 k decay fractal dimension 2 0 of the velocity power spectrum the smallest scale process characteristic scale 1 7 m requires a low fractal dimension 1 0 and accounts for 60 of the total rms velocity variation a comparison of successive logs from 6900 7140 m depth indicates that such variations are not repeatable and thus probably do not represent true velocity variations in the crust the results of this study resolve disparity between the differing published estimates of seismic heterogeneity based on the ktb sonic logs and bridge the gap between estimates of crustal heterogeneity from geologic maps and borehole logs

palaeoclimate interpretation of stable isotope data from lake sediment archives the isotope composition of authigenic and biogenic carbonates and diatom silica are commonly used as palaeoclimate proxies from lake sediments this article reviews the controls on the isotope composition of lacustrine skeletal and non skeletal deposits and illustrates how stable isotope studies contribute to an understanding of changes in temperature precipitation patterns evaporation and the carbon cycle it highlights the differences in the palaeoclimate potential of a wide range of lakes ranging from open to closed lake basins a large number of the case histories but not all are drawn from studies of temperate lakes from europe large closed lake systems in the tropics and elsewhere lose water predominantly through evaporation and contain sediments with variable and generally high 18o values fluctuations in the isotope composition of authigenic or biogenic minerals are mainly a function of long term changes in the precipitation evaporation ratio in contrast small open lakes which have a degree of through flow typically contain sediments with 18o values that vary by no more than a few these variations are generally ascribed to variations in temperature or the isotope composition of precipitation p from which either an annual or seasonally specific signal can be gained these types of lakes are common in northern europe and at high altitudes the interpretation of isotope data from a lacustrine succession requires a knowledge of the local processes that might control and modify the signal their effects need to be quantified and a robust calibration using the modern lake system is necessary to establish the relationship between the measured signal the isotopic composition of the host waters and climate

late holocene hydrological history of lake tanganyika east africa from isotopic data on fossil stromatolites abstract lake tanganyika situated in the western branch of the east african rift system shows a slightly positive water budget and generates a small outflow through the lukuga river dependent mainly on the ruzizi river inflow from lake kivu in the northern part of the basin conditions more arid than those presently observed closed the kivu basin from 3800 to 1300 yr b p previous studies esimated that the closure of the corresponding tanganyika basin lowered the lake level by 75 150 m in this paper we present the results of isotopic and morphologic analyses of fossil stromatolites the stromatolites formed as thick incrustations on hard substrates and are found at depths between 6 and 60 m below the modern lake level their isotopic composition 18o 13c 14c very precisely document late holocene water levels and hydrologic fluctuations in the lake tanganyika basin with reference to the actual situation a major low stand at 10 m below present level is identified from 3400 to 1900 yr b p with a rapid recession and gradual rise to modern levels maximum 18o values vs pdb in the stromatolites rose from ca 3 5 at 3400 yr b p to 6 at 2500 yr b p then decreased progressively to 1 6 at 1300 yr b p these values are interpreted as a maximum aridity episode culminating at ca 2500 yr b p at which time a negative precipitation evaporation p e ratio resulted in a much higher residence time of paleolake waters and thus a noticeable enrichment in 18o the observed decoupling of the isotopic ratio 18o 16o and water volume responses is thought to be linked to the inertia of the large rift aquifers which controlled the paleolake level

a review of palaeoclimates and palaeoenvironments in the levant and eastern mediterranean from 25 000 to 5000 years bp setting the environmental background for the evolution of human civilisation abstract the southern levant has a long history of human habitation and it has been previously suggested that climatic changes during the late pleistocene holocene stimulated changes in human behaviour and society in order to evaluate such linkages it is necessary to have a detailed understanding of the climate record we have conducted an extensive and up to date review of terrestrial and marine climatic conditions in the levant and eastern mediterranean during the last 25 000 years we firstly present data from general circulation models gcms simulating the climate for the last glacial maximum lgm and evaluate the output of the model by reference to geological climate proxy data we consider the types of climate data available from different environments and proxies and then present the spatial climatic picture for key climatic events this exercise suggests that the major northern hemisphere climatic fluctuations of the last 25 000 years are recorded in the eastern mediterranean and levantine region however this review also highlights problems and inadequacies with the existing data

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

was the climate of the eemian stable a quantitative climate reconstruction from seven european pollen records the aim of the present study is to estimate the range of the climatic variability during the eemian interglacial which lasted about 10 000 years marine isotopic stage 5e the modem pollen analogue technique is applied to seven high resolution pollen records from france and poland to infer the annual precipitation and the mean temperature of the coldest month the succession of pollen taxa and the reconstructed climate can be interpreted coherently the warmest winter temperatures are centred in the first three millennia of the eemian interglacial during the mixed oak forest phase with quercus and corylus as dominant trees a rapid shift to cooler winter temperatures of about 6 degrees to 10 degrees c occurred between 4000 and 5000 years after the beginning of the eemian related to the spread of the carpinus forest this shift is more obvious for the reconstructed temperatures than for precipitation and is unique and irreversible for the whole eemian period following this climatic shift of the eemian variations of temperature and precipitation during the fast 5000 years were only slight with an amplitude of about 2 degrees to 4 degrees c and 200 to 400 mm yr the estimated temperature changes were certainly not as strong as those reconstructed for the stage 6 5e termination or the transition 5e 5d this is consistent with the constantly high ratio of tree pollen throughout the eemian indicative of a succession of temperate forest types this gradual transition between different forest landscapes can be related to intrinsic competition between the species rather than to a drastic climatic change c 1998 elsevier science b v all rights reserved

defining biominerals and organominerals direct and indirect indicators of life abstract by introducing the new term organomineral to apply to minerals that are affected by organics mostly life related but not directly produced by living cells we hope to increase the accuracy of the terminology in present usage we believe that the term biomineral does not describe all mineral deposits precisely enough and offer case studies to support instances where the use of the new term organomineral is more appropriate we provide examples of some materials that are biominerals such as those in diatoms and human bones and which perform a functional purpose we then attempt to show that terminology can sometimes mislead investigators drive the direction and prejudice interpretations of scientific investigation this is achieved by presenting case studies of minerals that have been investigated as biominerals although they may not actually be directly controlled by biology for this reason we pay special attention to desert varnish hot spring siliceous deposits stromatolites and bacterial encrustations we go on to explain why we regard biominerals as direct indictors of life whereas organominerals should be treated as indirect indicators of life that require careful characterization to establish the origin of contained organics and whether these are biotic in origin how organic compounds are preserved and transformed in sedimentary environments and in the mineral matrix is as highly relevant to the study of modern earth environments as it is in the search for the oldest evidence of life in the terrestrial rock record it is also important to many disciplines such as microbiology and archaeology and especially to scientists planning missions to look for evidence of life on other planetary surfaces

vegetation and climate during the lgm and the last deglaciation on hokkaido and sakhalin islands in the northwest pacific abstract in the process of reviewing pollen data from hokkaido and sakhalin three facts were confirmed 1 the climate was revised to one colder than the last glacial maximum lgm during the last deglaciation in the last glacial period called the kenbuchi stadial which was related to the southward shift of the summer position of the kuroshio oyashio sea current boundary which affected not only northern hokkaido but also eastern hokkaido and northwestern sakhalin 2 from marine isotope stage 3 8000 cal yr bp grassland and mire that developed in hokkaido were characterized by expanded spikemoss which grows in snowpatch grassland and mire in the alpine zone of hokkaido and northern honshu today 3 during the lgm thermokarst depressions so called alas likely formed in eastern hokkaido along the sea of okhotsk based on the yield of the aquatic plants menyanthes and botryococcus in lgm sediments

late holocene climate variability on the eastern flank of the patagonian andes chile a δ18o record from mollusks in lago cisnes 47 s stable isotopes in mollusk shells have been widely used for hydrological balance reconstructions however their use is restricted to lakes that preserve the calcareous material of the shells lago

glacial mediterranean sea surface temperatures based on planktonic foraminiferal assemblages we present a new reconstruction of mediterranean sea surface temperatures sst during the last glacial maximum lgm a calibration data set based on census counts of 23 species of planktonic foraminifera in 129 north atlantic and 145 mediterranean core top samples was used to develop summer winter and annual average sst reconstructions using artificial neural networks anns and the revised analogue method ram prediction errors determined by cross validation of the calibration data set ranged between 0 5 and 1 1 c with both techniques being most successful in predicting winter ssts glacial reconstructions are based on a new expanded data set of 273 samples in 37 cores with consistent minimum level of age control the new lgm reconstructions suggest that the east west temperature gradient during the glacial summer was 9 c whereas during the glacial winter the gradient was 6 c both some 4 c higher than that existing today in contrast to earlier studies our results tend to suggest much cooler sst estimates throughout the glacial mediterranean particularly in the eastern basin where previous sst reconstructions indicated a decrease of only 1 c our new sst reconstructions will provide the modelling community with a detailed and updated portrayal of the mediterranean sea during the lgm setting new targets on which glacial simulations can be tested

北部北海道の剣淵盆地におけるmis7以降の植生と気候の変遷史 特にmis 6 5eとmis 2 1について

fractional levy motion as a model for spatial variability in sedimentary rock a new approach to the modeling of spatial variability in sedimentary formations is introduced this approach avoids the assumption of gaussian behavior specifically borehole measurements of physical properties of sedimentary rock from contrasting geological settings are shown to have a statistical character consistent with fractional levy motion successive increments in the measurement sequences are accurately modeled as having levy stable distributions the levy parameters are similar for boreholes in the same sedimentary basin but vary from basin to basin thinly bedded formations have smaller values for the levy index suggesting that the levy index may be a useful measure of heterogeneity the measurement sequences are also statistically self similar and have long range negative dependence among the increments antipersistence in addition to reproducing the statistical properties of well logs the new model also mimics the most striking visual features of sedimentary formations

lithologic characterization of a reservoir using continuous wavelet transforms we consider the problem of characterizing the lithology of a reservoir using gamma ray logs as well as seismic traces around the well we first calculate the continuous wavelet transform of the the data and then use the fact that the energy of such transformation is proportional to a power of its scale the technique consists in estimating the power transformation obtaining a set of values of the same size as the original data and then modeling the distribution of these values using a double exponential we find that wells that are predominantly sand correspond to distributions that are significantly different from those that correspond to wells that are predominantly gravel this happens in both cases gamma rays and seismic traces we use this characterization to classify other points in the reservoir

climate change in the turkana basin as deduced from a 4000 year long δo18 record abstract a model of the oxygen isotopic composition of lake turkana waters sheds insight into the paleoclimatic interpretation of a 18 o profile of inorganic calcite from a core taken from the lake the model indicates that high frequency fluctuations seen in the isotopic record are probably due to shifts in lake level while the long term increase of 1 4 seen from 4 to 2 kyr bp cannot be due solely to lake level change it must be due to changes in other climatic parameters such as the isotopic composition of the inflow these findings suggests that the abrupt change observed in lake turkana and many other african lakes at 4 ka was the precursor to a 2000 year long adjustment in the climate over the ethiopian plateau the isotopic record from lake turkana agrees with other paleoclimate records from the basin including the diatom stratigraphy and radiocarbon dates on exposed shoreline deposits

age palaeoenvironments and climatic significance of late pleistocene konya lake turkey abstract the konya basin a closed depression at the southern margin of the anatolian plateau contained a shallow but extensive lake during the late quaternary nearshore sands and gravels containing dreissena shells form prominent depositional terraces around the basin edges at elevations between 1005 and 1020 m and the highest has been dated at more than 30 000 yr b p the last major phase of limnic sedimentation occurred between 23 000 and 17 000 yr b p after which the lake fragmented into a number of subbasins or secondary depressions which evolved to become either marshes or playas a final expansion of these residual lakes has been dated to ca 11 000 yr b p in one secondary depression archaeological and other evidence indicate that only minor lake level fluctuations occurred during the holocene the dominant sedimentary process over the last 10 000 years has been alluviation at the basin margin the konya sequence confirms that the most recent period of high lake levels in the northern near east was of the last glacial age the palaeolakes of anatolia and iran were however more a product of reduced evaporation brought about by temperature depression than of changes in precipitation and thus belie their often used description as an indicator of pluvial climatic conditions

the tempo of holocene climatic change in the eastern mediterranean region new high resolution crater lake sediment data from central turkey this study presents results from a multi proxy analysis of cores taken in a crater lake sequence from eski acigol in central turkey which cover the period from pre c 16000 cal yr bp to the present the sediments comprise an upper unit of generally non laminated banded to massive silts and peats of mid to late holocene age overlying a laminated unit of late pleistocene to early mid holocene age the laminae comprising mainly aragonite amorphous silica diatom frustules and organic matter were formed in a relatively deep dilute meromictic lake pollen data indicate an abrupt replacement of artemisia chenopod steppe by grass oak terebinth parkland during the period of laminae deposition marking the start of the holocene a gradual increase in tree pollen during the early holocene came to an end c 6500 cal yr bp u series and adjusted c 14 timescale when mesic deciduous taxa declined at the same time as lake levels fell human impact on regional vegetation is inferred from a sharp decline in oak around 4500 4000 cal yr bp diatom isotopic and mineralogical data indicate that during the second half of the holocene the lake became relatively shallow and oscillated between fresh and brackish evaporated water conditions the contrast between wetter early and drier late holocene climatic conditions is matched by other eastern and central mediterranean proxy climate data while the eski acigol sequence resembles holocene hydroclimatic changes in the saharo arabian zone and was also apparently linked to orbital forcing it is unlikely to have had the same direct cause i e an expansion and subsequent retreat of monsoon rainfall

stable isotopic compositions of recent freshwater cyanobacterial carbonates from the british isles local and regional environmental controls recent 50 years old freshwater cyanobacterial carbonates from diverse environments streams lakes waterfalls throughout britain and ireland were analysed for their stable carbon and oxygen isotope compositions the mean 18o value of 5 9 pdb for river and stream data represents calcite precipitation in equilibrium with the mean oxygen isotopic composition of precipitation in central britain 7 5 smow assuming a mean water temperature of 9 c the mean 18o of lake data 4 5 pdb is statistically different reflecting the effects of residence time and or variations in the oxygen isotopic composition of rainfall carbon isotopes have wide variations in both fluviatile and lake data sets 3 to 12 pdb these variations are principally controlled in the fluviatile samples by contribution of isotopically light soil zone carbon relative to isotopically heavier carbon from limestone aquifer rock dissolution lake samples have the heaviest carbon isotope values reflecting a trend toward isotopic equilibrium between atmospheric co2 and aqueous hco 3 we infer that isotopic compositions of ancient cyanobacterial carbonates should also record environmental information although the effects of stabilization and diagenesis on primary 18o values will need careful consideration primary carbon isotope compositions should be well preserved although in marine samples values will be buffered by the isotopic composition of aqueous marine bicarbonate

fluctuations in the east asian monsoon over the last 144ka in the northwest pacific based on a high resolution pollen analysis of images core md01 2421 abstract a high resolution pollen analysis of images core md01 2421 45 83 m from the northwest pacific off central japan was used to clarify the vegetation history of central japan over the past 144 ka an age model was constructed using the oxygen isotope stratigraphy of benthic foraminifera 12 accelerator mass spectrometry ams 14c datings and two tephra layers with known eruption ages the pollen temperature index t p 1 0 0 t w t c t w where tw is the sum of temperate taxa and tc the sum of subalpine taxa values were high during 129 119 115 100 82 76 53 49 and 15 0 ka cool temperate broad leaved forests developed during the high tp periods and subalpine conifer forests grew during the low tp periods the tp fluctuated synchronously with summer insolation at 36 n where the core was collected during periods with abundant cryptomeria or sciadopitys 120 118 115 89 78 70 and 4 0 3 ka the east asian summer monsoon was stronger and the annual precipitation was greater in central japan than at present 2000 vs 1500 mm fluctuations in the sea surface temperature sst calculated from the oxygen isotopes of foraminifera in core md01 2421 and changes in the strength of the summer monsoon were synchronous the sst was determined by the currents passing over the core site rather than by the strength of summer insolation northward movement high sst of the kuroshio current which is under the influence of the summer okhotsk high pressure was strong near the summer insolation minima when precipitation was high particularly around 116 94 and 71 ka thus the strengths of both summer insolation and the east asian summer monsoon have determined the vegetation history of central japan for the last 144 ka

multi proxy paleoenvironmental reconstruction of saline lake carbonates paleoclimatic and paleogeographic implications priabonian rupelian issirac basin se france abstract a 200 m thick carbonate succession has been deposited in shallow water saline lake environments during the priabonian rupelian in the issirac basin south east france the palaeoenvironmental and palaeogeographic significance of such saline lake carbonates has been characterized on the basis of a multi proxy analysis including 1 depositional and diagenetic features 2 biological components molluscs ostracods benthic foraminifers characean and 3 carbon oxygen and strontium stable isotopes biological associations are indicative of dominantly shallow

stable isotopes of oxygen and hydrogen in the truckee river pyramid lake surface water system 3 source of water vapor overlying pyramid lake during 1988 and 1989 a series of water vapor extractions were conducted in the pyramid lake basin to determine the source of moisture that overlies the lake calculations of the isotopic and water vapor balances were made from isotopic and meteorological data from the pyramid lake and reno nevada areas the results indicate that in the warm season most of the moisture that overlies the lake is derived from evaporation as opposed to advected moisture isotopic fluxes at the lake surface can be approximated by climatic data from the lake site which simplifies the calculation of this input in numerical simulations of the isotopic evolution of the lake the stable isotopic composition of a lake is a function of the volume weighted isotopic values of each component of the lake s hydrologic balance researchers have used the stable isotope history of a lake together with the volume weighted isotopic composition of easily measured components of the hydrologic balance to estimate the stable isotope values or amounts of less easily measured components of the hydrologic balance see iaea 1970 1979 it is usually relatively simple to quantify the amounts and isotopic compositions of components of the surface water system and the isotopic composition of groundwater it is often more difficult to quantify the amount and direction of groundwater transport across the sediment water interface and the amount and isotopic composition of lake surface evaporation the isotopic value of water evaporated from a lake is highly dependent on the isotopic value acknowledgments we express our appreciation to those who assisted in sampling including jim davis dan mosley and nancy vucinich special thanks to irving friedman who loaned us the copper traps used for water vapor extraction to carol kendall and tyler coplen who oversaw the isotopic analyses to james ashby who maintained the weather stations and to steve hostetler who extracted the meteorological data from the weather station database and stratified the wind data for the sutcliffc and northshore sites we also thank zell peterman steve hostetler and pieter tans for reviews of earlier versions of this manuscript

contribution of allochthonous organic carbon across the serrano river basin and the adjacent fjord system in southern chilean patagonia insights from the combined use of stable isotope and fatty acid biomarkers abstract chilean patagonia is characterized by an irregular geography involving many islands peninsulas channels sounds and fjords that prevent direct interaction between oceanic water masses and freshwater river discharges at the head of the continental fjords in this paper we evaluate the potential sources and composition of organic matter along the serrano river basin and the adjacent channels and fjords in southern chilean patagonia 51 52 s as well as their importance for marine planktonic organisms in spring of 2009 evidence of c n ratio 13 c 15 n and fatty acids composition in particulate organic carbon poc surface sediment soil plankton and vegetal tissue as well some physical and chemical characteristics i e salinity dissolved oxygen no 3 nh 4 po 4 3 si oh 4 were measured in samples collected during the cimar 14 fiordos oceanographic cruise significant differences in 13 c poc were found between the terrestrial and marine environments but not within fjord stations along the fjord region the high c n ratio and depleted 13 c values in poc samples suggest that particulate organic matter pom in the upper level of the water column 0 10 m depth is supported by different sources terrestrial organic carbon exported by rivers may constitute a significant subsidy up to 70 based on two end member mixing model to the fjord ecosystem furthermore terrestrial carbon might account for a significant percentage of the zooplankton body carbon estimated both by using isotopic 24 61 and fatty acid analysis 14 61 isotopic analyses in marine sediment samples suggest that poc seems to be decoupled from terrestrial influenced surface sources at the fjord stations and the contribution of surrounding vegetation seemingly unimportant for carbon export to the benthos local hydrographic and geomorphological characteristics might determine the presence of oceanographic frontal zones which in turn might explain differences in carbon sources found between pom and the surface sediments

paleoclimatic significance of lacustrine microbialites a stable isotope case study of two lakes at torres del paine southern chile article two patagonian lakes studied here lago sarmiento and laguna amarga are located within the orographic rain shadow formed to the east of the southern patagonian ice field in the andes range major thrombolite colonies are present in lago sarmiento whereas widespread stromatolites occur in laguna amarga based on the characterization of the hydrologic system of these two lakes together with an estimation of the isotopic balance and an analysis of the equilibrium conditions between the water and biologically induced carbonates it is concluded that the microbialites of lago sarmiento are better suited as paleotemperature indicators than those of laguna amarga lago sarmiento thrombolites contain unique carbonate mineral species in which carbonate precipitation occurs close to isotopic equilibrium and where the variation in water temperature controls fractionation of the stable oxygen isotope the results indicate that at 1215 cal yr bp the level of the lake was at 85 m a s l with a temperature close to 9 3 c was at 82 m a s l at 600 cal yr bp with a temperature close to 8 5 c this coincides with the timing of the northern hemisphere medieval warming period at 183 cal yr bp the level of the lake was at 80 m a s l with a cooler temperature close to 7 7 c representing a colder period coinciding with the timing of the little ice age lia an interesting outcome of this study is that it reinforces the idea that the 13 c signal in carbonate deposits can be an effective tool in distinguishing between inorganic and biologically induced precipitation

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

seismic facies characterization by monoscale analysis relating sedimentary records to seismic data is a major challenge by shifting focus to a scale invariant sharpness characterization for the reflectors we develop an attribute that can capture and categorize the main reflector features without being sensitive to amplitudes sharpness is defined by a scale exponent which expresses singularity order and determines the reflection signature waveform local scale exponent estimates are obtained with a new monoscale method compared to multiscale wavelet analysis our method has the advantage of measuring transition exponents at a single fixed scale using a simple on off criterion the exponents contain amplitude variation information and describe lithological onsets we create an image of the earth s local singularity structure by applying our method to seismic traces and well log data the singularity map facilitates interpretation facies characterization and integration of well and seismic data

great salt lake utah microbialite δ13c δ18o and δ15n record fluctuations in lake biogeochemistry since the late pleistocene extensive lacustrine microbialite deposits exposed along the shores of great salt lake gsl utah preserve a rich continental paleoenvironmental record newly reported microbialite carbon and oxygen stable isotope ratios in carbonate nitrogen isotope ratios in organic matter and organic matter radiocarbon ages archive paleolake hydrological and biogeochemical changes from the late pleistocene through the holocene positive correlations between 18o and 13c in 15 7 6 cal ka microbialite carbonate are consistent with a hydrologically closed basin lake with fluctuations in volume chemistry and associated changes in lake primary production the 15n of microbialite bulk organic matter 5 18 versus air shows that the balance between nitrogen fixation and assimilation of dissolved inorganic nitrogen has varied significantly inverse 18o and 13c correlations in combination with high 15n in some carbonate deposits may imply periods of higher salinity and stable lake stratification similar to modern gsl conditions we compare our c and o data sets with pleistocene lake bonneville carbonate stable isotope records and demonstrate progressive development of spatially isolated hydrological basins during the shift to warmer and drier conditions in the holocene

deep borehole log evidence for fractal distribution of fractures in crystalline rock summary sonic velocity and electrical resistivity logs run to a depth of 3 5 km in crystalline rock near the san andreas fault at cajon pass in southern california correlate over scale lengths both small sub metre and large tens to hundreds of metres no such correlations are seen with the more lithologically sensitive natural gamma intensity log the correlation between the sonic velocity and electrical resistivity logs suggests that a non lithologic property of the crystalline rock controls fluctuations in situ fracture intensity is a logical candidate for the controlling rock property the fluctuations of the individual sonic velocity and electrical resistivity logs are examined with the hurst rescaled range parameter over borehole log intervals 1 5 m l 1500 m for log fluctuations arising from a scale invariant physical process the hurst rescaled range scales with data interval as lh 0 h 1 a purely random sequence of in situ fractures produces a scaling exponent h 0 50 fluctuations in the cajon pass sonic velocity and electrical resistivity logs yield h 0 70 evidence that in situ fracture sets tend to occur in clusters rather than at purely random intervals the tendency for fracture clustering over log intervals 1 5 m l 1500 m suggests that fracture formation is a fractal process independent of length scale in which larger fracture intervals form from clustering of numerous smaller fracture intervals seismic reflectivity derived from the borehole sonic velocity log is also scale independent over the range of data intervals 1 5m l 1500 m with a hurst exponent h 0 21 if we associate fracture clustering with crustal fault formation the cajon pass borehole sonic velocity and electrical resistivity logs predict that crustal faults scale fractally with fractal dimension d 2 30 the equivalent b value for earthquake size distribution is b d 2 1 15 on this hypothesis observed b values 1 15 indicate a tendency for earthquakes to cluster on existing weak faults a scale independent mechanics for crystalline rock fracture formation in which larger scale fractures form as clusters of smaller scale fractures provides a mechanical link between the small pervasive stress aligned flaws cracks and microfractures which can impart anisotropy to crystalline rock and the larger scale fractures associated with finite strain and faulting thus in crustal regions of active but low strain fracture anisotropy is observed to be aligned with the inferred maximum principal stress while in actively faulted crust fracture anisotropy is observed to be more nearly fault parallel as if the fractures are aligned by the finite strain faulting process

oxygen isotopes in meteoric calcite cements as indicators of continental paleoclimate because meteoric water 18 o values decrease with decreasing ambient temperature and increasing latitude 18 o values of meteoric calcite cement should exhibit a similar relation with paleolatitude and be an indicator of continental paleotemperatures to test this we compiled isotopic and paleolatitude data for 20 meteoric cements and nine speleothems ranging in age from devonian to modern and in paleolatitude from 3 5 to 83 mean 18 o values for meteoric cements and speleothems both show the same negative correlation with paleolatitude the 18 o vs latitude trend for these carbonates is almost identical to that predicted for modern inland environments but differs from the trend for coastal environments this suggests that the ground water controlling the ultimate composition of meteoric cement is derived predominantly from inland recharge if it is assumed that the modern meteoric water 18 o vs temperature relation is valid for the past and that insignificant evaporation occurred prior to carbonate precipitation then coastal and inland paleotemperatures can be calculated from the 18 o values of meteoric calcite 18 o mcl and seawater 18 o sw by using the equations t coastal 13 3 32 6 0 231 0 0613 18 o mcl 18 o sw and t inland 17 8 16 2 0 572 0 1233 18 o mcl 18 o sw where t is temperature in c calcite precipitated from coastal meteoric water at temperatures between 0 and 25 c will exhibit a narrow range in 18 o 6 to 4 where 18 o sw 0 the 18 o of calcite precipitated from inland meteoric water will be sensitive to paleotemperature ranging from 14 to 5 where 18 o sw 0 for temperatures of 0 to 25 c

fracture network characterization using 1d and 2d data of the moragy granite body southern hungary abstract a disposal system for low and medium level nuclear waste in hungary is being constructed inside the fractured rock body of the lower carboniferous moragy granite previous studies proved that the granitoid massif is rather heterogeneous in terms of lithological composition brittle structure and hydrodynamic behaviour a significant part of the body consists of monzogranite while other portions are more mafic in composition and are monzonites as a result of at least three significant brittle deformation events the area is at present crosscut by wide shear zones that separate intensively fractured zones and poorly deformed domains among them due to late mineralization processes some of these fractured zones are totally sealed and cannot conduct fluids while others are excellent migration pathways the spatial distribution of these two types nevertheless does not show any systematics hydrodynamic behaviour clearly reflects this heterogeneous picture in some places hydraulic jumps as great as 25 m at compartment boundaries can be detected in this study the fracture network of the moragy granite body is evaluated from a geometric aspect using datasets measured at a wide range of scales 2d digitized images of a hand specimen one large 20 60 m and 12 smaller subvertical wall rocks outcrops and 120 images from tunnel faces representing the ground level of the underground repository site were analysed moreover 1d data from 13 wells that all penetrate the granitoid massif were studied based on measured geometric data spatial position length orientation and aperture fracture networks are simulated to study connectivity relations and for computing the fractured porosity and permeability at different scales the results prove the scale invariant geometry of the fracture system geostatistical calculations indicate that measurable fracture geometry parameters behave as regionalized variables and so can be extended spatially estimated localities of connected subsystems fit very well with fault zones mapped previously moreover the spatial position of regimes of different hydrodynamic behaviours can be explained by connectivity relations both regionally and within wells

renewed glacial activity during the antarctic cold reversal and persistence of cold conditions until 11 5 ka in southwestern patagonia resolving the timing direction and magnitude of paleoclimate changes in the southern midlatitudes is a prerequisite for determining the mechanisms underlying abrupt and widespread climate changes between the hemispheres during the last glacial interglacial transition lgit this issue is still debated with previous studies producing apparently discordant fi ndings here we show evidence for a glacial readvance and a cold episode between ca 14 8 and 12 6 ka in southwestern patagonia 50 s contemporaneous with the antarctic cold reversal this was followed by ice recession under cold but relatively milder conditions until ca 11 5 ka when paleovegetation records indicate the onset of warm interglacial conditions these fi ndings differ from those reported in northern patagonia 40 s where deteriorating conditions before 13 5 ka were followed by the coldest part of the lgit that lasted until ca 11 5 ka we interpret the apparent blend of greenlandic and antarctic cold phases as evidence for their co occurrence in the southern middle latitudes in patagonia and hypothesize that the position of the antarctic polar front modulated the strength of these cold events in regions to the north or south of it

a high resolution late holocene lake isotope record from turkey and links to north atlantic and monsoon climate a high resolution proxy record of precipitation and evaporation variability through the past 1700 yr from 18o analysis of a varved lake sequence from central turkey shows rapid shifts between dry periods ad 300 500 and ad 1400 1950 and wetter intervals ad 560 750 and ad 1000 1350 changes are consistent with changes in instrumental and proxy records of the indian monsoon dry summers in the eastern mediterranean being associated with periods of enhanced monsoon rainfall in addition major shifts in the record are coherent with changes in north atlantic winter climate with cold wet periods in the alps occurring at times of dry turkish climate

some remarks on the estimation of fractal scaling parameters from borehole wire line logs well logging provides a direct means of assessing fluctuations in petrophysical properties with depth and thus allows for the statistical characterisation of crustal heterogeneity using records from three super deep boreholes ktb and cajon pass and synthetic data we assess three different techniques for estimating fractal dimension and correlation length inaccurate correlation lengths may result from the way in which the autocorrelation is calculated for well logs leading to an incorrect application of the von karman function analysis of the rescaled range power spectra and autocorrelation allow us to model the data as k where k wavenumber and exponent 5 2d for fractal dimension d process with values of fractal dimension displaying anti persistence

fault scaling and 1 f noise scaling of seismic velocity fluctuations in the upper crystalline crust sonic logs are detailed measurements of the in situ seismic velocity along borehole walls power spectra of sonic logs typically decay approximately as the reciprocal of spatial frequency f regardless of the chemical composition geologic age and tectonic history of the probed lithologies data sequences of this type are fractal or scale invariant the origins of this uniform 1 f scaling of seismic structure are not clear particularly in low porosity crystalline rocks but faults fractures and cracks are considered to be important fault structures also follow fractal scaling laws and have significant effects on seismic velocity this paper presents a quantitative model that evaluates the role played by faults in determining the scaling laws of seismic velocity fluctuations the model is based on current knowledge of the structure and scaling properties of brittle faults and of associated regions of microcracking by approximating the relationship between crack density and velocity variation as linear this model yields a brownian power spectrum 1 f 2 for velocity perturbations across a single fault zone in a medium of otherwise constant velocity the power spectrum of velocity fluctuations induced by a population of faults is then obtained by superposing the corresponding brownian power spectra weighted according to the observed frequency size scaling relationship of brittle faults the results of this study indicate that the uniform 1 f scaling of velocity fluctuations in crystalline rocks seems to be linked to the correspondingly uniform scaling properties of fault structures

spectral analyses of the ktb sonic and density logs using robust nonparametric methods we use robust techniques to estimate power spectra coherences and transfer functions of the german continental deep drilling program ktb sonic and density logs and lithologically defined subsets thereof our results confirm the overall 1 wavelength decay of the power spectra inferred by parametric analyses but provide superior resolution and nonparametric estimates of errors and statistical significance we demonstrate the absence of any statistically meaningful coherence between the velocity logs from the main and pilot holes suggesting a spatially quasi isotropic upper crustal velocity structure also there is little coherence between the physical and caliper logs indicating that disturbances introduced by breakouts and uneven relief of the borehole wall mostly contribute to the uncorrelated portions of the velocity logs coherence between the gamma and physical logs is weak to absent indicating that the observed velocity and density fluctuations are dominated by the physical state of the rocks rather than by their petrological composition attempts to derive poisson s ratio and its variation with wavelength from the relationship between the shear and compressional velocity logs met with limited success but imply that caution should be exercised when comparing poisson s ratio derived from laboratory studies on samples representative of a region to crustal scale seismic determinations our preferred interpretation is that fluctuations in the physical logs in the intermediate wavelength range 10 150 m are dominated by cracks and their level of fluid saturation at larger wavelengths 50 150 m the effects of the petrology becomes more significant as shown by changes in slope of the power spectra and the emerging coherence between the vp and the gamma logs

palaeoecology of lake zeribar iran in the pleniglacial lateglacial and holocene reconstructed from plant macrofossils changes inaquatic andmarshvegetation atlakezeribar inthezagros mountains iran during thelast 40000years werereconstructed onthebasis ofplant macrofossils several episodes oflowwater level andincreased salinity wereevidenced bypeaks ofchenopodium rubrum seeds andtheoccurrence of obligate salicornia sp ruppia maritima andsuaeda sp andfacultative zannichellia palustris halophytic macrophytes aswell asbrackish water andmarine diatoms someofthese events canbecorrelated withan increase indiatoms indicative ofhigher conductivity andwithchanges inoxygen isotope data theyare interpreted astheexpression ofgeneral climatic dryness although water level changes might alsohave resulted fromepisodes ofdeposition onthealluvial fans that damthelake a fewsuchwater level changes occurred inthepleniglacial themostpronounced lowering corresponds totheyounger dryas interval of high climatic aridity macrofossil indicators ofwater level changes appeared also intheholocene section oftheprofiles atthesametime asquercus expanded onthesurrounding uplands culminating about 6000 500014cyrbp giving support tothehypothesis that thedelay offorest expansion inthis partofthezagros mountains wascaused byclimatic dryness

fluctuations of the south patagonian ice field during the last glaciation and the holocene mapping along a transect from the southeastern margin of the south patagonian ice field in torres del paine national park chile to the limits of fresh moraines of the last glacial cycle indentified eight glacier advances the four younger ones have been dated by dendrochronology tephrochronology and radiocarbon dating although the bases of 10 m deep bogs were sampled close limiting radiocarbon dates were not obtained because bog formation in this rain shadow area appears not to have commenced until ca 12000 yr ago the outermost little ice age moraine formed during the seventeenth century and three inner ones were deposited around ad 1805 1845 and after 1890 densely vegetated older moraines contiguous with little ice age deposits are possibly of late holocene age tephra from the eruption of reclus volcano at ca 11 880 yr bp was incorporated by a readvance that deposited large multiple moraines 10 16 km from the modern ice front the oldest basal peat found inside the moraine has been dated to ca 9200 yr bp these bracketing dates indicate that some eastern outlet glaciers of the ice field advanced at a time when some western tidewater outlet glaciers terminated inside their modern limits this questions the view of j h mercer and other that patagonian glaciers did not readvance during the late glacial interval a stadial event also occurred when the glaciers were some 18 20 km from their modern positions and is closely dated to ca 11880 yr bp because reclus pumice flushed down glacier forms thick upper beds in outwash deltas deposited in proglacial lakes the four older moraines pre date the late glacial eruption of reclus but are not dated closely comparison of their spatial extent with well dated moraines in the chilean lakes region suggests that they may mark advances culminating at ca 14000 yr bp ca 20000 yr bp and earlier

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

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

the dune systems of the konya plain turkey their relation to environmental changes in central anatolia during the late pleistocene and holocene abstract several sand flats located on the northern shores of the late pleistocene palaeolake of the konya plain inner anatolia turkey are related to changes in lake levels in this paper the two main dune systems are mapped according to their geomorphological sedimentological and dynamic characteristics and their significance is discussed with regard to the environmental changes since the late pleistocene both at time of the former lake and during the drier periods of the holocene cross sections show the relationship of the dunes to the topography of the basement analyses of the sand fraction show distinct characteristics in size distribution quartz and shell contents wind erosion effects on the quartz grains and petrographic composition interpretation of the results coupled with information provided by the geomorphology of the dune systems studied in the field and from aerial photographs and satellite images highlights the importance and variations in time of local factors such as prevailing winds sand sources changes in lake levels and vegetation a chronology of the main sand fields is proposed based on the evidence of three main droughts during the upper pleistocene the older one much eroded maximum height 3 m covers a limestone surface at 50 m above the bottom of the dried lake an optical scanning luminescence osl date shows a last period of accumulation at 14 328 3220 years the younger one maximum height 12 m has moved over the emerged late pleistocene lacustrine marls an osl date gives an age of 5674 988 years for the last accumulation period evidence of very recent activation of this younger dune system is apparent as a result of overgrazing and excessive land reclamation a third period of dominant wind action and dune construction is responsible for the installation of a younger and thin dune field over the mid holocene lacustrine deposits of the karapinar lake the success of the stabilization programme of the dunes over the last 30 years shows that the last period of dune movement is not related to climate change but to overpressure on the land due to the needs and activities of an increasing population

rapid late miocene surface uplift of the central anatolian plateau margin abstract the central anatolian plateau cap turkey is bordered to its south by a steep mountain belt that emerged 8 7 ma ago from the mediterranean sea knowledge of the onset duration and rate of surface uplift and orographic barrier formation along the plateau margin is crucial for understanding the geodynamic drivers of plateau uplift we present a new comprehensive data set that includes 12 40ar 39ar ages and lacustrine carbonate 18 o data n 637 from 13 sections in upper oligocene to pliocene continental basins of the cap interior we aim at documenting the development of a rain shadow and therefore the surface uplift history of the cap and its southern margin tauride mts in the rain shadow of the tauride mts we observe a gradual 3 9 decrease of 18 o values of lacustrine carbonate between 11 and 5 ma that we interpret to originate from a similar change in 18 o values of precipitation owing to the late miocene development of an orographic barrier our stable isotope paleoaltimetry data show that by 5 ma the southern cap margin had reached similar to present elevations of 2 km surface uplift was coeval with ignimbritic magmatism forearc shortening and distributed compression we suggest that the removal of lithospheric mantle below anatolia led to surface uplift of the cap interior which was followed by surface uplift of the southern cap margin due to crustal thickening as a result of northward subduction of the african plate below central anatolia

mediterranean vegetation lake levels and palaeoclimate at the last glacial maximum the apparent conflict between pollen evidence for widespread artemisia steppe1 6 implying semi arid conditions and geomorphological evidence for high lake levels4 7 11 has produced controversy about the ice age palaeoclimate of the mediterranean region here we use a water balance model12 to predict catchment runoff and a biome model13 to predict vegetation type to reconstruct the palaeoenvironment around lake loannina a type locality for the northern mediterranean region we show that both sets of evidence are compatible with a summer dry winter wet regime with seasonal temperature anomalies similar to those predicted by atmospheric model simulations of the last glacial maximum14 18 the drying effect of the cold north atlantic ocean may have been counteracted in winter by increased storm frequency under a southward shifted jet stream as shown by several atmospheric models16 18

comparison of eastern atlantic atmospheric trajectories for present day and last glacial maximum abstract for three deep sea core positions in the eastern atlantic ocean off africa gik 15669 34 53 n 7 49 w gik 16415 9 34 n 19 06 w and geob 1016 11 46 s 11 41 e 4 day isobaric back trajectories calculated on the 850 hpa level are presented the trajectories were computed for present day pd and for the last glacial maximum lgm cluster analysis was used for a concise assessment of trajectories the trajectories are clustered by year to investigate the interannual variability of the flow patterns and also by month for investigating the seasonal cycle the results indicate that for gik 15669 and geob 1016 the flow patterns are the same for both time slices but the wind speed was higher during the lgm for gik 16415 the flow pattern changed significantly from the lgm to pd and the wind speed was lower during the lgm

from pleniglacial to holocene a 14c chronostratigraphy of environmental changes in the konya plain turkey abstract in the endoreic semi arid konya basin on the central anatolian plateaux long term hydrological evolution has left various landforms and lacustrine deposits reflecting the regional climatic evolution as well as human influence on the local environments this paper presents results from a cooperative programme grouping several institutes from turkey and france on lacustrine marshy and aeolian sediment sequences of upper pleistocene and holocene age the detailed study of environmental evolution is based on the reconstruction as well as on the characterization of the extension and contraction phases of wetlands occupying the lowest parts of the konya plain a soil and a marsh layer are 14c dated ca 28 000 25 000 yr bp three phases of pleniglacial from ca 22 000 to 17 000 yr bp high lake levels are distinguished complementary osl dates on aeolian dunes confirm the occurrence of two drought periods the first occurs around the start of the late glacial the second after the mid holocene climatic optimum the latter being in phase with a similar drought in other eastern mediterranean regions after 17 000 yr bp no lacustrine phase reached as high a level as the pleniglacial lake during the late glacial a shallow freshwater lacustrine phase is identified from 12 500 to 11 000 yr bp the late glacial to holocene transition corresponds to a general absence of deposits and dateable material thus suggesting a period of drought to which no aeolian features have so far been related the holocene environmental evolution shows a period of marsh and shallow lake extansion from 6000 to 5500 yr bp this wetter period is interrupted by the second drought ca 5500 yrs bp as indicated by aeolian dune activity during the late holocene a renewal of marshes as well as soil development on slopes can be interpreted either as climatic changes or as impacts of human use of water and soil resources during prehistoric and historic times

a lateglacial climatic reversion in hokkaido northeast asia inferred from the larix pollen record abstract at present larix gmelini is a main component of taiga developed in north sakhalin northeast china and east siberia during the interval from 11 8 to 12 4 ka bp pollen assemblages from north hokkaido japan are dominated by larix pollen assemblages of this lateglacial climatic reversal known as the kenbuchi stadial are similar to pollen assemblages from the last glacial maximum in north hokkaido vegetation of hokkaido inferred from these pollen assemblages open taiga composed of larix gmelini pinus pumila and picea jezoensis and or picea glehnii may have been like that of north sakhalin today comparison of these fossil pollen assemblages from hokkaido with pollen assemblages from modern surface samples in sakhalin suggests that 11 8 to 12 4 ka bp temperatures relative to today were at least 9 c lower in january and 7 c lower in august and that annual precipitation was at least 735 mm lower than present

on the cause of 1 f power spectral scaling in borehole sonic logs borehole logs provide in situ information about the scaling of fluctuations in the elastic properties of rock a surprising finding has been the widespread 1 f type 0 5 1 5 scaling of borehole sonic log power spectra yielding no clear correlation with geological age type or history raising questions about the reliability and origin of these findings ubiquitous fractures for example have been evoked as the most likely explanation of these results firstly we show that the smoothing effects of the logging tool must be taken into account in order to obtain reliable values of we then investigate the scaling properties of lithology only in perfectly exposed metamorphic rock by explicitly excluding fractures we find clear 1 f scaling for reconstructed velocity data based solely on lithological variations although fractures are certainly important in contributing to 1 f fluctuations in borehole logs intrinsic geology may also play a significant role

constraints on hydrological and paleotemperature variations in the eastern mediterranean region in the last 140 ka given by the δd values of speleothem fluid inclusions abstract speleothem fluid inclusions potentially provide vital data on the paleohydrological conditions in glacial and interglacial periods we show here that d analyses of fluid inclusions from speleothems in three caves in the eastern mediterranean region israel provide a basis for understanding hydrological and temperature variations in the last 140 ka using measured d fluid inclusion values and temperature ranges constrained by the present day mediterranean meteoric water line mmwl and the global mwl we show a strong compatibility between the land and marine temperature records with the highest land temperatures occurring at 120 130 ka 17 22 c and the present 18 c and the lowest temperatures during the lgm about 10 c lower than present interglacial waters are constrained to follow the mmwl and most glacial waters also plot close to the mmwl with a slight shift towards the mwl however during two remarkable brief periods at the termination of the lgm the waters plot on the mwl suggesting that both sharp cooling and an increase in relative humidity above the em sea reduced d excess values to those of the global system

temperature and salinity variations of mediterranean sea surface waters over the last 16 000 years from records of planktonic stable oxygen isotopes and alkenone unsaturation ratios alkenone unsaturation ratios and planktonic d18o records from sediment cores of the alboran ionian and levantine basins in the mediterranean sea show pronounced variations in paleo temperatures and salinities of surface waters over the last 16 000 years average sea surface temperatures ssts are low during the last glacial averages prior to 13 000 years 11 15 c vary rapidly at the beginning of the holocene and increase to 17 18 ca t all sites during s1 formation dated between 9500 and 6600 calendar years the modern temperature gradient 2 3 c between the mediterranean sub basins is maintained during formation of sapropel s1 in the eastern mediterranean sea after s1 ssts have remained uniform in the alboran sea at 18 c and have fluctuated around 20 c in the ionian and levantine basin sites the d18o of planktonic foraminifer calcite decreases by 2 from the late glacial to s1 sediments in the ionian basin and by 2 8 in the levantine basin in the alboran sea the decrease is 1 7 of the 2 8 decrease in the levantine basin the evect of global ice volume accounts for a maximum of 1 05 and the temperature increase explains only a maximum of 1 3 the remainder is attributed to salinity changes we use the temperature and salinity estimates to calculate seawater density changes they indicate that a reversal of water mass circulation is not a likely explanation for increased carbon burial during s1 time instead it appears that intermediate and deep water formation may have shifted to the ionian sea approximately 2000 years before onset of s1 deposition because surface waters were as cold but saltier than surface water in the levantine basin during the younger dryas sapropel s1 began to form at the same time when a significant density decrease also occurred in the ionian sea 2000 elsevier science b v all rights reserved

palaeoclimate and the formation of sapropel s1 inferences from late quaternary lacustrine and marine sequences in the central mediterranean region abstract synchronous responses to climatic changes during the late pleistocene holocene transition are inferred from marine and lacustrine stratigraphic records in the central mediterranean region new stratigraphic data are presented from well dated sequences in the meso adriatic depression mad two crater lakes in the lazio region and in the tyrrhenian sea the sequences all span the last termination and the holocene but we focus here on the evidence in each record for the time period during which sapropel s1 formed in the mediterranean ca 9 0 to 6 8 cal kyr b p the new records provide evidence of palaeoenvironmental changes on land and sea that can be reconstructed at a high temporal resolution and which throw some light on the processes which led to the formation of s1 the collective evidence indicates that i organic rich sediments occurred in both the marine and the crater lake sites during the time of formation of the s1 sapropel ii there is evidence of increased stratification and anoxia in the sea water column during the period of s1 formation iii the s1 period in the study area is divisible into two sub phases s1a and s1b which reflect short term variations in oceanographic conditions stratification and anoxia iv changes in stratification in the marine column were contemporaneous with regional climate variations that are inferred from the terrestrial records we conclude that the key factor that initiated the formation of s1 was increased discharge of freshwater into the mediterranean following a change post 9 0 cal kyr b p to a warmer and wetter climate furthermore the period of s1 formation was interrupted by a short lived episode ca 500 years of comparatively cooler and drier conditions during the early middle holocene transition emht

european lakes as palaeohydrological and palaeoclimatic indicators abstract lakes in temperate regions have fluctuated in size on annual to millenial time scales changes in water level or depth can be reconstructed by applying geomorphic sedimentological and biostratigraphic methods to transects of sediment cores this systematic field based approach has been used at a number of sites in europe it is illustrated by reconstructions of water level changes in lakes from southern sweden these lakes have shown broadly synchronous changes during the holocene such synchronous changes in water levels at several sites in a region reflect climatic changes inferences about the mechanism of the climatic change depend on identifying both synchronous changes within a region and differences in the direction magnitude and timing of lake level changes between regions continental compilations of lake level data are therefore necessary detailed studies are not available from enough sites but the interpretation of already existing stratigraphic and biostratigraphic data in terms of lake level changes has greatly increased the number of sites available for a continental scale synthesis in europe this eclectic literature based approach is illustrated with examples from southern europe lakes in the mediterranean region were high around the glacial maximum and again somtime during the first half of the holocene in the western mediterranean the peak of late glacial aridity occurred at 15 000 16 000 bp and the lakes were already high again by 12 000 bp in the east maximum late glacial aridity occurred between 13 000 and 11 000 bp and there was a gradual return to wetter climates during the early holocene such that 9000 bp was more arid than 6000 bp most lakes in the mediterranean region were high at 6000 bp the transition to arid conditions after 5000 bp occurred abruptly in the west and more gradually in the east the lakes of southern sweden indicate drier climates in the early holocene ca 9000 bp more effective moisture between 8000 and 6000 bp increased aridity between 5500 and 3500 bp and increased effective moisture again during the last 3000 years the history of lake level changes in southern sweden and the mediterranean region can be partially explained in terms of changes in the direct effects of insolation and in the strength and position of the westerlies and of the subtropical high pressure cell during the late quaternary