late miocene to pliocene palaeogeography of the paratethys and its relation to the mediterranean abstract the palaeogeographic evolution of the paratethyan and mediterranean realms are reconstructed with three maps ranging from the late miocene to the middle late pliocene the maps are based on the facial analysis of selected deposits clastic input slope slide process analyses as well as biogeographic data of the planktic benthic and terrestrial biota characteristic fossil assemblages are used for palaeobathymetric and palaeohydrologic interpretations restoration of palaeogeographic connections the palaeogeographic reconstructions are palinspastically restored after dercourt j ricou l e vrielynck b eds 1993 atlas tethys palaeoenvironmental maps gauthier villars paris pp 1 307 14 maps the paleogeographic atlas of northern eurasia 1997 inst tectonics lithospheric plates moscow 26 maps with modifications maps have been prepared for the terminal tortonian early messinian late pannonian early maeotian late messinian pontian salinity crisis time and piacenzian gelasian akchagilian they illustrate the neogene palaeogeographic evolution during and after the attic orogenesis though the emerging mountain system of the alpine foldbelt increasingly separated the paratethys from the mediterranean tethys paratethys connections remained extant and sufficiently effective for limited communication between both basins they governed many features of the cyclic depositional history and biogeographic evolution of the eastern paratethys

mediterranean sea surface radiocarbon reservoir age changes since the last glacial maximum sea surface reservoir ages must be known to establish a common chronological framework for marine continental and cryospheric paleoproxies and are crucial for understanding ocean continent climatic relationships and the paleoventilation of the ocean radiocarbon dates of planktonic foraminifera and tephra contemporaneously deposited over mediterranean marine and terrestrial regions reveal that the reservoir ages were similar to the modern one 400 years during most of the past 18 000 carbon 14 years however reservoir ages increased by a factor of 2 at the beginning of the last deglaciation this is attributed to changes of the north atlantic thermohaline circulation during the massive ice discharge event heinrich 1

geoarchaeological evidence for dredging in tyre s ancient harbour levant abstract chrono stratigraphic data from tyre s ancient northern harbour delineate extensive dredging practices during the greco roman and byzantine periods radiocarbon dates from four cores consistently cluster between ca 500 b c and 1000 a d and indicate rapid rates of sedimentation in the basin namely 10 mm yr during the greco roman and byzantine periods compared to 0 5 1 mm yr for the period 6000 4000 b c absence of strata between 4000 b c and 500 b c is not consistent with a natural base level sediment sink and cannot be interpreted as a depositional hiatus in the high stand systems tract ancient dredging is further corroborated by persistent age depth inversions within the fine grained harbour facies these data support removal of middle bronze age to persian period sediment strata with deliberate overdeepening of the harbour bottom by greco roman and byzantine societies

geoarchaeology of tyre s ancient northern harbour phoenicia tyre s ancient northern harbour has been a source of scientific intrigue and debate for many centuries today an insignificant fishing harbour looking north and sheltered from the dominant winds by a sandstone reef system is all that remains of the famous bronze age phoenician hellenistic roman and byzantine anchorage havens in light of this many scholars have long questioned whether the modern port corresponds to its counterpart in antiquity here we provide litho and biostratigraphical evidence for an ancient harbour approximately twice as large as the present comprising the modern day harbour and city centre four distinct sedimentary units have been identified translating the different holocene palaeoenvironments 1 the holocene transgressive contact is dated ca 7800 bp and lies at the base of a silty clay lithodependant unit our proxies are consistent with a low energy lagoonal type environment protected by an extensive reef system 2 transition to a coarse sand fraction after ca 5500 bp is concomitant with the accretion of a semi protected pocket beach this environment served as a proto harbour during the middle bronze age mba 3 after the mba artificial harbour sedimentation is represented by a fine grained silty sand unit with stress on the natural biosystem this unit attests to a closed marine lagoonal type environment which existed until around 1500 bp dredging activity during the roman and byzantine periods explains the absence of 1st millennium bc strata 4 the economic decline of the ancient city after the byzantine period is marked by the opening of the basin to greater marine influence with a progradation of the harbour coastline natural sediment infilling diminished the size of the harbour to its present dimensions lost until now beneath the medieval and modern centres

northern westerlies during the last glacial maximum results from cmip5 simulations abstractbased upon simulations from phase 5 of the coupled model intercomparison project cmip5 the vertical and regional characteristics of the northern westerlies during the last glacial maximum lgm are investigated in this study at the northern hemispheric scale all nine available models simulate a poleward shift of the 200 hpa jet and eight models simulate an equatorward shift of the 850 hpa jet compared to the preindustrial period these shifts are of approximately 2 3 latitude for the arithmetic multimodel mean the upper tropospheric cooling in the tropics possibly due to reduced latent heat release is expected to account for the poleward shift of the 200 hpa jet through the thermal wind relationship changes in the midlatitude baroclinic instability in response to the amplified polar cooling are associated with the jet stream in the lower troposphere through anomalous eddy activity in particular the types of predominant baroclinic eddies are regionally dependent the behavior of the 8

directional wave measurement at haifa israel and sediment transport along the nile littoral cell abstract results of three years of directional wave measurement at the eastern mediterranean coast of haifa israel are presented the wave height and energy flux distributions reveal a moderately high energy coast with a bimodal annual cycle the rate of wave induced longshore sediment transport is estimated from the directional energy flux distributions it describes an annual cycle with a maximum northward transport of 75 14 10 3 m 3 month in midwinter and a southward transport of 26 5 10 3 m 3 month in summer the net annual transport is northward and computed at 110 100 10 3 m 3 yr we show that a wave induced transport is sufficient in explaining the apparent transport of sediments in the nile littoral cell from the nile delta source to the haifa bay sink

stratigraphy of late holocene deposits of the ancient harbour of marseilles southern france the late holocene stratigraphy of marseilles harbour is presented together with archaeological evi dence and radiocarbon data an anthropogenic oyster midden dated between c 4260 and 3400 14 c yr bp is followed by a period of siltation that ended the accretionary growth of an algal marl deposit this event was caused by early human settlement subsequently the coastline was subject to progradation it is argued here that the development of the e rst town of marseilles c 2600 years ago accelerated soil erosion and sediment deposition in the harbour area

geoscience of ancient mediterranean harbours abstract although much has been written on the subject of ancient mediterranean harbours the relatively new area of harbour geoarchaeology remains dispersed in the geoscience and archaeological literature over a decade of research has amassed rich and varied datasets of anthropogenically forced coastal evolution with a remarkable number of between site analogies this new research field also shows the rich potential of geoscience to reconcile important archaeological questions no single publication however has yet drawn on these geological patterns to yield a detailed overview suitable for geoscientists and environmental archaeologists the aim of this review article is to 1 discuss how ancient harbours have come to be preserved in the geological record 2 expound the basic principles and palaeoenvironmental tools underpinning ancient harbour geoarchaeology 3 outline some of the most significant research advances made and 4 discuss a new chrono stratigraphic model applicable to harbour sequences

sedimentological evidence of an assumed ancient anchorage in the hinterland of a phoenician settlement guadiana estuary sw spain abstract as bays lagoons and estuaries ensure protection from wind and a hinterland rich in natural resources is most enticing during the early iron age the seafaring phoenician settlers chose such locations all over the mediterranean for their seaports establishing pan mediterranean trade from the late 9th century bce onwards despite the difficult nautical conditions phoenician sailors had conquered the strait of gibraltar by the end of the 9th century bce today many of these sites along the mediterranean and atlantic coasts are located several kilometers inland due to coastal progradation this paper investigates whether the wetlands of the estero de la nao a tidal channel and small tributary within the lower guadiana estuary gulf of cadiz sw iberia were able to serve as a potential natural harbor location and port of trade for the seafaring phoenician population the focus of this study is set on a systematic analysis of sedimentological data the lithostratigraphy of three sediment cores shows that at least 8000 years ago open water conditions existed within a marine embayment characterized by sedimentation under estuarine conditions this situation prevailed for several millennia from the early bronze age silting up processes of the former navigable areas occurred additionally a distinct stratigraphic gap within the sedimentary sequence of one particular sediment core provides strong evidence of ancient dredging activities that attempted to cope with the local siltation processes in the most recent strata badly sorted sediments intercalated with brick and shell fragments provide evidence of a high energy event probably triggered by the great lisbon earthquake in 1755

paleometeorology high resolution northern hemisphere wintertime mid latitude dynamics during the last glacial maximum 1 hourly winter weather of the last glacial maximum lgm is simulated using the community climate model version 3 ccm3 on a globally resolved t170 75 km grid results are compared to a longer lgm climatological run with the same boundary conditions and monthly saves hourly scale animations are used to enhance interpretations the purpose of the study is to explore whether additional insights into ice age conditions can be gleaned by going beyond the standard employment of monthly average model statistics to infer ice age weather and climate results for both lgm runs indicate a decrease in north atlantic and increase in north pacific cyclogenesis storm trajectories react to the mechanical forcing of the laurentide ice sheet with pacific storms tracking over middle alaska and northern canada terminating in the labrador sea this result is coincident with other model results in also showing a significant reduction in greenland wintertime precipitation a response supported by ice core evidence higher temporal resolution puts in sharper focus the close tracking of pacific storms along the west coast of north america this response is consistent with increased poleward heat transport in the lgm climatological run and could help explain early glacial warming inferred in this region from proxy climate records additional analyses shows a large increase in central asian surface gustiness that support observational inferences that upper level winds associated with asian pacific storms transported asian dust to greenland during the lgm

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

montane bias in lowland amazonian peatlands plant assembly on heterogeneous landscapes and potential significance to palynological inference abstract past temperature changes in tropical mountain regions are commonly inferred from vertical elevational shifts of montane indicator taxa in the palynological record however temperature is one of several abiotic factors driving the low elevational limits of species and many montane taxa can occur in warmer lowlands by tracking appropriate habitat types especially highly flooded wetlands in this paper we explore ways in which lowland habitat heterogeneity might introduce error into paleo temperature reconstructions based on field data of seven modern peatland vegetation communities in the southern peruvian amazon 200 masl peat rich substrates are common edaphic transitions in pollen cores and provide detailed records of past vegetation change the data show that indicators of modern peatlands include genera with montane as well as lowland distributions while indicators of surrounding forests on mineral substrates have predominantly lowland distributions based on family level analyses we find that modern peatland vegetation communities have taxonomic compositions appearing to be 389 m to 1557 m mean 1050 391 m above their actual elevations due to a high abundance and number of families with high elevation optima we interpret the relatively higher prevalence of montane elements in modern peatlands as habitat tracking of a conserved montane niche on heterogeneous lowland landscapes we suggest that both high moisture availability and stressful edaphic conditions of peatland habitat may explain the montane bias observed to the extent that fossilization provides a better record of past vegetation that occurred proximate to the site of deposition we suggest that habitat tracking of montane elements may introduce a cool bias in lowland paleo temperature reconstructions based on pollen proxies

linkages between climate fire and vegetation in southwest china during the last 18 5ka based on a sedimentary record of black carbon and its isotopic composition abstract fires are sensitive to climate changes and in addition they have a major influence on the global carbon cycle land surface properties and chemical composition of the atmosphere which in turn can affect the climate system projecting the impacts of future climate changes on fire mediated biogeochemical processes requires understanding of how various climatic factors influence regional fire regimes however long term variations in fire activity and their controls are poorly known in this study we report the concentration of black carbon bc and its isotopic composition 13cbc in an upland lake sediment core from southwest china in order to elucidate linkages between changes in fire regime climate and vegetation over the past 18 5 ka the results show that the sedimentary bc content recorded variations in fire activity and exhibits a close negative correlation with the amount of precipitation delivered by the indian summer monsoon ism during heinrich event 1 18 5 15 0 cal ka bp the younger dryas 12 8 11 1 cal ka bp and the mid to late holocene the weakening of the ism led to greatly increased fire activity in southwest china in the last 1 0 ka the bc record may have been affected by human activity in the catchment which may have caused an increased influx of minerogenic material to the lake thereby diluting the sedimentary bc concentration the general trend of changing vegetation compositions inferred from the 13cbc values also tracks the variations of the ism suggesting a change from mixed c3 c4 plant ecosystems during the last glacial maximum to c3 plant dominated forest during the holocene however the abundance of c4 plants may be overestimated during the bolling allerod warm interval and the early holocene due to the fact that fires were probably limited to the savanna ecosystem in the valleys and low lying basins

coastal reconstruction of vista alegre an ancient maritime maya settlement abstract past coastal reconstruction is useful for understanding archaeological coastal settlements and predicting how coastal change might affect modern populations the ancient maritime maya inhabitants of vista alegre in the northeastern yucatan were active seafaring peoples however the past coastal landscape environmental history is unknown previous research concentrated on the fully terrestrial component of the site and did not approach the issue from an earth sciences sedimentological perspective in this study a sediment core campaign in the shallow offshore of vista alegre aimed to reconstruct the coastal and environmental changes that occurred over the past 3000 years and specifically identify the changes in sea level nine cores were analyzed using a multi proxy approach including a range of sedimentological parameters such as granulometry micropaleontology foraminifera radiocarbon dating and loss on ignition the sediment cores provided an archive of environmental changes related to sea level change anthropogenic influence and shifting microenvironments which can be associated with cultural time periods the environmental phases and shifts show some linkage to the archaeological chronology suggesting an association between the environmental conditions and human activities sea level changes and shifting shorelines have always been and still are a challenge for coastal settlements and ancient sites can be a harbinger of what to anticipate in the future in addition to this current natural and anthropogenic pressures on coastlines are placing archaeological sites at increasing risk and thereby threatening this important scientific and cultural archive therefore efforts to identify characterize and record natural and anthropogenic pressures prior to destruction are increasingly important

reconstruction of the landscape history around the remnant arch of the klidhi roman bridge thessaloniki plain north central greece abstract this paper deals with the palaeoenvironmental reconstruction of the area surrounding the remnant arch of the ancient bridge of klidhi thessaloniki plain greece 19th century travellers and 20th century historians discussed the age of the monument and concluded that it was built during late roman times 3rd cent ad and supported a branch of the via egnatia road however few studies have considered the environmental context of the construction of the bridge and until now only two hypotheses have been presented the bridge was built on or over a junction of the aliakmon and loudias rivers or on a coastal barrier within the framework of a geoarchaeological project developed in april 2008 five boreholes were drilled and the sediment cores analysed for microfauna and sedimentology seven 14 c ams dates provided a chronostratigraphic sequence and helped to define the geomorphological evolution of the area spatial interpretation of the results was possible using a landsat tm image false colour composite fcc our data indicate the gradual transition of the site from a marine to a terrestrial environment during ancient times lagoonal conditions dominated during the construction of the bridge and the presence of a palaeochannel of the aliakmon river was later revealed transition from byzantine and ottoman periods overlying sediments of a coastal barrier

the ancient harbour parasequence anthropogenic forcing of the stratigraphic highstand record abstract unique chronostratigraphic similarities are observed in recent geoscience literature on ancient mediterranean harbours from these empirical port data a clear pattern of millennial anthropogenic forcing marked by a fining up sequence can be discerned in coastal stratigraphy the stratigraphic peculiarity of this artificial or human modified parasequence leads us to define a new working model the ancient harbour parasequence

the palaeozoogeography of oligocene to recent marine ostracoda from the neotropics mid and south america and antarctica abstract classic biogeographical research has shown that the continent of south america supports a diverse and priceless biota of which ostracods are an important component the distribution patterns of oligocene to recent shelf ostracods from the neotropics to antarctica are explained in terms of dispersal and vicariant events the quantitative examination of a newly constructed database containing over 140 genera has allowed the measurement of generic similarity and endemicity between biotas of different geographical regions the measurement of these parameters has aided the construction of a series of palaeoendemicity and communality maps these maps emphasise changes in the spatio temporal distribution of mid to late tertiary ostracods and can aid in the recognition of abiotic mechanisms that modify genera distribution it has been demonstrated that changes in the oceanic currents and water mass temperature are significant in the formation and maintenance of zoogeographical domains in the oligocene recent of the neotropics and antarctica south america was an important centre of origin for ostracods during the oligocene however few genera appear able to disperse northwards towards the caribbean the migratory success or failure of benthonic ostracods is closely linked to oceanographical and climatic conditions and their physiology within the meso american region filter and corridor pathways have allowed rapid dispersal of shallow water ostracods which has lead to decreased endemism although a distinctive ostracod assemblage was established in the oligocene of antarctica the expansion of the drake passage permitted a new suite of cryophilic genera to emerge on the continent during the mio pliocene within the meso american region the alteration of oceanic circulation patterns subsequent to the closure of the panamanian portal may have initiated the development of a proto panamanian province in the early pliocene

the upper tortonian lower messinian at monte dei corvi northern apennines italy completing a mediterranean reference section for the tortonian stage abstract a high resolution integrated stratigraphy including biostratigraphy magnetostratigraphy tephrostratigraphy and cyclostratigraphy is presented for the upper tortonian and lower messinian upper miocene at monte dei corvi numerical age control comes from a combination of magnetobiostratigrapic dating and astronomical tuning while radioisotope dating of ash layers produced less reliable ages the deep marine succession is characterized by large scale non repetitive stratigraphic changes allowing the discrimination between a lower brownish rossini and euxinic shale interval the sedimentary cycles which occur superimposed on these large scale changes are related to astronomical climate forcing astronomical tuning of the sedimentary cycles provides not only absolute ages for biostratigraphic events reversal boundaries and volcanic ash layers but also for the observed non cyclic changes these can be linked to environmental and geodynamic changes in the mediterranean region preceding the messinian salinity crisis the beginning of the brownish interval marked by tripartite cycles at 8 017 ma coincides with tectonic re arrangements in the mediterranean such as compression in the betics and opening of the rifian corridor at 7 616 ma the change to the calcareous rossini interval can be linked to tectonic uplift in the northern apennines and the deepening of the rifian corridor while the betic corridor became restricted coinciding with the end of evaporite deposition in the eastern betics the change to euxinic shales at 7 168 ma reflects basin wide restriction marked by diatomite and sapropel formation in the mediterranean basin related to the severely constricted betic and rifian corridors the occurrence of a tripartite construction of cycles in the euxinic shales at 6 719 ma coincides with diatomite formation in the eastern mediterranean uplift and shallowing in the northern apennines and further constriction of the atlantic gateways we conclude that late tortonian early messinian tectonic and environmental events occur remarkably synchronously in the mediterranean basin and most likely result from a combination of geodynamic processes and eccentricity controlled climatic changes in combination with the upper serravallian and lower tortonian interval which includes the formal tortonian global stratotype section and point gssp the monte dei corvi is the only complete section in the mediterranean covering the entire tortonian stage we therefore propose the monte dei corvi section as tortonian reference section particularly for the mediterranean region in addition it may serve as a unit stratotype for the tortonian

foraminiferal faunal estimates of paleotemperature circumventing the no analog problem yields cool ice age tropics the sensitivity of the tropics to climate change particularly the amplitude of glacial to interglacial changes in sea surface temperature sst is one of the great controversies in paleoclimatology here we reassess faunal estimates of ice age ssts focusing on the problem of no analog planktonic foraminiferal assemblages in the equatorial oceans that confounds both classical transfer function and modern analog methods a new calibration strategy developed here which uses past variability of species to define robust faunal assemblages solves the no analog problem and reveals ice age cooling of 5 o to 6oc in the equatorial current systems of the atlantic and eastern pacific oceans classical transfer functions underestimated temperature changes in some areas of the tropical oceans because core top assemblages misrepresented the ice age faunal assemblages our finding is consistent with some geochemical estimates and model predictions of greater ice age cooling in the tropics than was inferred by climate long range investigation mapping and prediction climap 1981 and thus may help to resolve a long standing controversy our new foraminiferal transfer function suggests that such cooling was limited to the equatorial current systems however and supports climap s inference of stability of the subtropical gyre centers

variability in north pacific intermediate and deep water ventilation during heinrich events in two coupled climate models the responses of north pacific intermediate and deep water ventilation and ocean biogeochemical properties to northern north atlantic glacial freshwater perturbations are evaluated with a coupled atmosphere ocean general circulation model miroc and an earth system model of intermediate complexity loveclim when the atlantic meridional overturning circulation amoc is weakened as a result of the north atlantic freshwater discharge both models simulate subthermocline and intermediate water warming in the pacific ocean the sensitivities of the pacific meridional overturning circulation pmoc to amoc weakening differ significantly between the two models miroc simulates a small enhancement of the deep sinking branch of the pmoc in the north pacific on the contrary the loveclim freshwater experiment exhibits intensified deep water formation in the north pacific associated with a maximum transport change of 19 sv despite the significant differences in ocean circulation response both models successfully reproduce high oxygen and low nutrient conditions of intermediate and deep waters in accordance with sediment core based paleoproxy reconstructions from the north pacific and bering sea during heinrich event 1 emergence of younger intermediate and deep water in the north pacific can be partly attributed to an overall enhanced mixing as well as intensified overturning circulation of the subpolar north pacific our models simulate broad features observed in several paleoproxy data of the pacific ocean biological production decrease in northern japan cooling in the western north pacific ocean and the southward shift of the pacific intertropical convergence zone

abrupt changes in early holocene tropical sea surface temperature derived from coral records for many high latitude regions of the globe it is now clear that the transition to modern climate following the last glacial maximum was punctuated by a number of rapid and substantial climate oscillations1 2 in contrast relatively little is known about how the tropics responded to the deglaciation because few high resolution records are available from lower latitudes corals have recently been shown to provide an important source of tropical climate records because they can be easily and accurately dated using either 14c or 230th and because past sea surface temperatures can be recovered from the sr ca ratios in coral skeletons here we use this technique to derive several early holocene sea surface temperature records from a coral drill core recovered from espiritu santo vanuatu in the tropical southwest pacific ocean these records indicate that sea surface temperatures in this region were depressed by as much as 6 5 c below modern values at 10 350 calendar years bp but rose very abruptly during the following 1 500 years this temperature increase lags the post younger dryas increase observed in a coral record from the tropical atlantic ocean3by about 3 000 years an unexpected phase shift that may ultimately shed light on the mechanisms of deglacial climate change

the last glacial maximum stability and change in a western amazonian cloud forest the climatic and vegetation history of a western amazonian cloud forest is documen ted in a continuous pollen record spanning the full last glacial period between 43 5 and 22k cal yr bp the chronology for this record is based on eight radiocarbon dates yielding a low resolu tion pollen analysis for the region a bioclimatic envelope model was generated on the basis of mod ern altitudinal distributions and the pollen data which produced a glacial palaeotemperature estimate of ca 5 c relative to present palaeoecological evidence of continuous moist cloud forest cover in the basin indicates that western amazonian forests were not fragmented during the lgm this evidence supports wet conditions in western amazonia at the lgm and further refutes hypotheses of amazonian aridity during the last ca 44k cal yr bp copyright 2005 john wiley sons ltd

late quaternary carbon cycling responses to environmental change revealed by multi proxy analyses of a sediment core from an upland lake in southwest china stable carbon isotope 13c values of organic matter in lacustrine sediments are commonly used to trace past changes in terrestrial and aquatic carbon cycles here we use a high resolution well dated 13c record from lake tengchongqinghai tcqh in southwestern china together with other proxy indices to reconstruct the paleolimnological history over the past 18 5 ka organic matter in the sediments of lake tcqh is derived predominately from aquatic macrophytes the lacustrine primary productivity is closely linked with lake level changes affected by variations in the strength of the asian summer monsoon and modified by evapotranspiration similar to lake sediments world wide a ca 3 shift occurred in the 13c values of lake tcqh in response to the significant increase in atmospheric co2 concentration during the last deglaciation in the holocene the availability of dissolved co2 in the lake water of lake tcqh was determined by variations in hydraulic energy low water turbulence creates a thick stagnant boundary layer around aquatic plants which will restrict the rate of co2 diffusion and result in more positive 13c values of aquatic plants in contrast significant water turbulence dramatically reduces the boundary layer thickness leading to more negative 13c values of aquatic plants

geoarchaeology of beirut s ancient harbour phoenicia abstract this paper presents geoarchaeological results from the ancient harbour of beirut lebanon as at sidon knowledge of beirut s ancient tell has advanced significantly over the past decade thanks namely to redevelopment of the city centre and excavations centred on the modern port in spite of this research understanding of the city s coastal palaeoenvironments during antiquity is poor buried iron age harbourworks presently 300 m from the sea attest to pronounced coastal changes during the past 3000 years these processes have been significantly accentuated during the last two centuries by redevelopment of the port which remains in use some 5000 years after its foundation here we elucidate the coastal stratigraphy east and west of the bronze age tell to yield new insights into the evolution of the beirut seaboard in addition to the complex history of human environment interactions these chronostratigraphic data are subsequently used to 1 precisely locate the main anchorage haven during antiquity and 2 propose a chronology for its evolution

high resolution climate simulation of the last glacial maximum the climate of the last glacial maximum lgm is simulated with a high resolution atmospheric general circulation model the ncar ccm3 at spectral truncation of t170 corresponding to a grid cell size of roughly 75 km the purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography the lgm simulations were forced with modified climap sea ice distribution and sea surface temperatures sst reduced by 1 c ice sheet topography reduced co2 and 21 000 bp orbital parameters the high resolution model captures modern climate reasonably well in particular the distribution of heavy precipitation in the tropical pacific for the ice age case surface temperature simulated by the high resolution model agrees better with those of proxy estimates than does the low resolution model despite the fact that tropical ssts were only 2 1 c less than the control run there are many lowland tropical land areas 4 6 c colder than present comparison of t170 model results with the best constrained proxy temperature estimates noble gas concentrations in groundwater now yield no significant differences between model and observations there are also significant upland temperature changes in the best resolved tropical mountain belt the andes we provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells a longstanding model data discrepancy therefore appears to be resolved without invoking any unusual model physics the response of the asian summer monsoon can also be more clearly linked to local geography in the high resolution model than in the low resolution model this distinction should enable more confident validation of climate proxy data with the high resolution model elsewhere an inferred salinity increase in the subtropical north atlantic may have significant implications for ocean circulation changes during the lgm a large part of the amazon and congo basins are simulated to be substantially drier in the ice age consistent with many but not all paleo data these results suggest that there are considerable benefits derived from high resolution model regarding regional climate responses and that observationalists can now compare their results with models that resolve geography at a resolution comparable to that which the proxy data represent

core top calibration of mg ca in tropical foraminifera refining paleotemperature estimation 1 optimal use of mg ca as a paleotemperature proxy requires establishing calibrations for different species of foraminifera and quantifying the influence of dissolution to achieve this goal we have measured mg ca and 18o in a series of tropical and subtropical core tops including four depth transects the ceara rise the sierra leone rise and the rio grande plateau in the atlantic and the ontong java plateau in the pacific focusing on spinose mixed layer dwelling species globigerinoides ruber and globigerinoides sacculifer and nonspinose thermocline dwelling neogloboquadrina dutertrei shell mg ca in g sacculifer is 5 15 lower than in g ruber while n dutertrei mg ca is 49 55 lower than in g ruber this statistically significant offset has allowed us to establish different calibrations for each species multilinear regression analysis was used to develop calibration equations that include a correction term for the dissolution effect on mg ca in foraminiferal calcite presented in this paper are two sets of calibrations one set using core depth as a dissolution correction and another using co32 as a dissolution parameter the calibrations suggest that g ruber is the most accurate recorder of surface temperature while g sacculifer records temperatures below the surface at 20 30 m the depth habitat of n dutertrei is more uncertain owing to the wide range in habitat depths depending on hydrographic conditions but on average mg ca and 18o data suggest it is at 50 m of the three species n dutertrei is the most sensitive to dissolution up to 23 decrease in shell mg ca per km while g sacculifer is the most resistant

new evidence of the age of the lower maeotian substage of the eastern paratethys based on astronomical cycles abstract the lower maeotian sedimentary rocks of the popov kamen section russia taman region eastern paratethys were investigated by cyclostratigraphy methods based on magnetic susceptibility measurements time series analysis lomb scargle and redfit periodograms wavelets gaussian filters revealed statistically significant signals with 5 2 6 0 m wavelength corresponding most likely to the 41 000 year obliquity cycle these new data imply a duration of the early maeotian regional substage of 0 9 myr and this sets the age of the sarmatian maeotian boundary to about 7 6 ma these astronomically tuned lower maeotian sediments of the popov kamen section result in an average sedimentation rate of about 11 12 cm kyr 90 9 83 3 yr cm for the whole section in the relatively deep water setting of the lower maeotian popov kamen section no major hiatuses were detected with the exception of an insignificant gap in the upper part of the successions the marine transgression in the eastern paratethys at the beginning of maeotian was probably caused by the opening and consequent deepening of rifian corridor at the end of the tortonian 7 6 ma this tectonic event terminated the restricted conditions in the mediterranean and re established the connection between the mediterranean sea and paratethys therefore the tortonian messinian transition in the mediterranean probably corresponds to the clays of the lower part of the lower maeotian record in paratethys which is located above the first bryozoan build ups and below the 1 8 m thick diatomite bed in the popov kamen section our astronomically calculated age for the beginning of the maeotian at 7 6 ma strengthens the connection between these two transgressive events

vegetation history climatic changes and indian summer monsoon evolution during the last glaciation 36 400 13 400 cal yr bp documented by sediments from xingyun lake yunnan china abstract we obtained a 9 74 m long sediment core xy08a from xingyun lake in central yunnan province southwest china and used ams radiocarbon dating of terrestrial plant macrofossils to provide a chronology here we present the results of pollen and grain size analyses of the interval 36 400 13 400 cal yr bp and discuss the vegetation history and record of climate change associated with the evolution of the indian summer monsoon ism three stages of regional vegetation change are documented i during the late marine isotope stage 3 36 400 29 200 cal yr bp the study region was occupied by mixed coniferous and evergreen broad leaved forest dominated by pinus and evergreen quercus with tsuga abies picea growing on the surrounding mountains ii during the last glacial maximum lgm 29 200 17 600 cal yr bp cold temperate coniferous forest dominated by species of abies picea expanded and reached a maximum extent and at the same time the extent of evergreen broadleaved forest increased iii from 17 600 to 13 400 cal yr bp the hemlock forest and abies picea forest began to decline until they disappeared completely in the early phase of the last deglaciation while pine forest and evergreen broadleaved forest dominated the surrounding areas the vegetation history indicates a generally drying climate from 36 400 to 13 400 cal yr bp suggesting a gradual weakening of the ism with the weakest ism influence occurring during the early part of the last deglaciation when the climate was the driest the regional temperature first decreased intermittently and then increased gradually being mild and wet during the late mis3 stage followed by the coldest but not the driest climate during the lgm when the temperature was at least 3 c lower than at present

pliocene arctic temperature constraints from the growth rings and isotopic composition of fossil larch instrumental records reveal that the current rate of arctic warming greatly exceeds mean global warming however arctic temperatures during the pliocene were considerably warmer than present making it an excellent time period for investigating potential consequences of current warming trends here we focus on an early pliocene 4 to 5 ma peat deposit from ellesmere island characterized by a remarkable fossil assemblage representative of a modern boreal forest among the fossils are wellpreserved samples of an extinct larch larix groenlandii which were exploited as an archive of paleoclimatic information we reconstruct pliocene terrestrial temperatures in the high arctic using a novel approach that combines measurements of ring width and oxygen isotopes this technique was calibrated by analyzing modern analog larch growing at the northern extent of their range and accounting for biotic fractionation of oxygen isotopes using a global database of modern trees based on this approach we estimated mean annual temperature in the arctic during the pliocene to be 5 5 1 9 c indicating that arctic temperatures were 14 2 c warmer than today this more precise multi proxy estimate is slightly warmer than previous estimates derived from empirical evidence and general circulation models our results also demonstrate that the biotic fractionation of oxygen isotopes in cellulose is non linear and dependent upon regional factors affecting aridity such as latitude and elevation therefore the simultaneous measurement of oxygen isotopes and morphological characteristics in paleovegetation can be useful in constraining climatic variables of earth s past

characteristics of storm waves off the mediterranean coast of israel abstract a two year series of directional wave measurement off the eastern mediterranean coast of israel reveals an abundance of high storm waves some of these waves have significant height in excess of 5 meters and periods as long as 15 sec the evolution of the storm waves is described and related to the growth and paths of the storm fronts in mid mediterranean shorter period waves are found to always lead the arrival of longer period swell this characteristic is explained by a short decay distance and or a high migration velocity of the storm front the scatter plot of significant wave height vs period for the recorded events of each storm describes an open loop time sequence the difference in period between that of the peak height event and the period of a fully arisen sea of the same height is found to be indicative of the true decay distance the waves have travelled

composition of clays along the continental shelf off israel contribution of the nile versus local sources the eastern mediterranean sedimentary regime is dominated by sediment transport from the nile river and its delta but recent studies have also suggested a certain contribution of clay fraction from streams to the continental shelf and slope off israel in the present study we focused on clay fraction deposition along the inner 40 1000 m water depth shelf of israel in order to substantiate and quantify its different sources for this purpose detailed xrd mineralogical determinations as well as chemical compositions of the clay 2 m fraction of marine and continental sediments were used the clay mineral composition of israeli stream sediments is variable with no distinct spatial or temporal trend but within a limited assemblage this clay assemblage is made up of illite smectite is phases 70 90 kaolinite 5 25 and illite 10 and is similar to that of the nile however it is clearly distinguished by the type of the is phases which are derived mainly from mesozoic outcrops and recent sediments soils and are less expandable than those of the nile which are derived mainly from weathered basalt the nile derived component is depleted in the marine clay fraction along the israel coast evidenced by a decrease of is expandability and the fe2o3 al2o3 ratio and an increase in the k2o al2o3 mgo al2o3 and cao al2o3 ratios the depletion is well pronounced north of tel aviv where the largest coastal plain stream flows to the sea a northward increase of carbonates in the clay fraction and particularly of the bioskeletal component is indicated by the ratios of mgo and sr to cao the contribution of the local streams to the shallow shelf marine clay fraction is estimated to be about 50 a minor contribution of desert dust is identified by the relative increase in kaolinite in the marine sediments south of tel aviv

the messinian event in the paratethys astronomical tuning of the black sea pontian abstract this study presents new data on the orbitally calibrated maeotian pontian and pontian record of the black sea basin paratethys obtained by time series analysis of magnetic susceptibility ms data from relatively deep water upper miocene sediments exposed in the zheleznyi rog section taman peninsula russia in the studied interval a 145 m long sedimentary sequence spectral analysis revealed statistically significant signals with 6 1 8 2 m and 3 0 4 0 m wavelength these signals correspond to the obliquity and precession cycles respectively this study correlates the main steps of messinian salinity crisis msc of the mediterranean to the black sea pontian record based on astronomical tuning of the study sequence and evaluation of integrated biostratigraphic paleomagnetic and sedimentological data based on cyclostratigraphic results maeotian pontian beds with actinocyclus octonarius accumulated from 6 3 to 6 1 ma most of the novorossian sediments correspond to the first msc step the tg 22 5 79 ma and tg 20 5 75 ma glacial events occur in the uppermost novorossian record and are marked by extraordinary high values of ms the portaferian dated at the base as 5 65 ma and the top as 5 45 ma corresponds to the second msc step the novorossian portaferian transition is marked by the hiatus of approximately 150 160 kyr which agrees well with the concept of the intra pontian unconformity in the black sea basin and a sea level drop in the mediterranean from 5 6 to 5 46 ma the ages for the base and the top of the bosphorian were estimated as 5 45 ma and 5 27 ma respectively the base of the bosphorian corresponds to the third lago mare episode caused by the high sea level connection between the mediterranean and eastern paratethys

some outstanding issues in the geology of lebanon and their importance in the tectonic evolution of the levantine region abstract the concept of pervasive and disruptive late neogene quaternary strike slip tectonics in lebanon has made establishing a satisfactory pre neogene palaeogeographic and palaeotectonic history for the area difficult research has allowed clarification of three fundamental issues that permit the setting of lebanon against its adjacent regions to be more firmly assigned the first issue is the identification of the significance of the 100 km long nne ssw trending monocline of the western lebanon flexure this feature is interpreted as a modified and rejuvenated early mesozoic hinge line that is presumed to be the northern continuation of the carmel sinai hinge line to the south the second issue is the correlation of the mount lebanon bekaa and anti lebanon complex with the adjacent intracontinental palmyride fold belt of syria through recognition in each of common divisions in structural style between a higher northern zone dominated by broadly spaced box folds and a lower southern zone with more numerous closely spaced and more internally complex folds the third issue involves the identification of major two stage late cretaceous to palaeogene syrian arc tectonism within lebanon resolution of these issues suggests a tectonic model for the region whereby the levantine region formed in two main phases the first of these was the multiphase late palaeozoic early mesozoic rifting of the area which imposed a fundamental extensional fabric over much of the region the second tectonic phase was the subsequent inversion of these extensional structures in the two stage syrian arc deformation of senonian and late palaeogene age which gave rise to the main lebanon structures it is this syrian arc tectonism rather than the late cenozoic strike slip that was probably the main structuring agent which affected the lebanon area the transpression from the braided dead sea fault motion although locally complex is an essentially neotectonic overprint on an already existing fabric offset of syrian arc structures in lebanon suggests that the total sinistral motion of the yammouneh fault segment of the dead sea fault is around 47 km

anthropogenic accumulation of metals and metalloids in carbonate rich sediments insights from the ancient harbor setting of tyre lebanon the antique and byzantine sediments of the northern harbor of tyre lebanon store high amounts of metals and metalloids as the result of a millennial anthropogenic contamination as well as of efficient trapping and immobilization processes geochemical and mineralogical analyses reveal the contrasted patterns for the accumulation of trace metal loid s in the sedimentary sequence recovered by coring the inner part now emerged of the ancient harbor lead sn cu and ag concentrations can be as high as 3000 150 1000 and 1 2 g g respectively enrichment factors were calculated with respect to 1 th and 2 the chemistry of the substratum and appear to be driven by anthropogenic inputs indeed a drastic change in both excess concentrations and concentration ratios is observed through roman and byzantine times pointing to major intensification of the trade and use of metals in tyre coherent with historical data good preservation of the archeological signal despite 1 sediment disturbances that have caused age depth inversions and 2 the large time lapse since the time of deposition of anthropogenic trace metal loid s is probably due to the reducing character of the sediments tyre s sedimentary sequence provides an interesting analog for modern carbonate rich harbor environments in which a millenary accumulation of trace metal loid s has been overall well preserved and suggests a restricted mobility of anthropogenic contamination for a period of time in excess of 1500 years

the myth of the messinian dardanelles late miocene stratigraphy and palaeogeography of the ancient aegean black sea gateway abstract the dardanelles region has formed a key gateway connecting the eastern paratethys and the aegean mediterranean since the late miocene its sedimentary sequences contain crucial information about connectivity and tectonics but so far lack unambiguous age constraints only a few miocene marine episodes have been documented and fossil assemblages are predominantly composed of paratethyan fauna mollusks and ostracods here we apply an integrated stratigraphic approach and use the recently established chronostratigraphy for the eastern paratethys to re evaluate the faunal assemblages and palaeoenvironments of the seddulbahir and intepe sections that allegedly played a crucial role in the geodynamic evolution of the dardanelles during the messinian zanclean the paratethyan ostracods and mollusks however clearly indicate that these sections correspond to the middle tortonian 9 ma bessarabian khersonian in eastern paratethys terminology nannofossil assemblages are dominated by a mixing of reworked taxa from the late eocene and oligocene and no age diagnostic taxa have been observed dinoflagellate analyses are also hampered by reworking and mainly reveal non marine fresh to oligohaline aquatic conditions fossil mammal remains in the seddulbahir section and other localities in the region confirm the late miocene age strontium 87sr 86sr isotope ratios of the anomalohaline brackish ostracods are significantly below open ocean values and similar to values obtained from khersonian ostracods of bulgaria fresh water assemblages reveal much higher 87sr 86sr values which are interpreted to reflect the composition of local rivers we conclude that in late miocene times the dardanelles region was a fresh to anomalohaline embayment ephemerally connected to the eastern paratethys we found no evidence for a major messinian erosional surface nor for marine mediterranean fossils indicative of the early zanclean our results furthermore indicate that the proposed messinian age for the propagation of the north anatolian fault into the dardanelles region must be revised

effects of quaternary sea level cycles on strontium in seawater abstract the effects of quaternary sea level changes on the sr budget of the ocean are investigated using coupled numerical models of the seawater sr and ca budgets glacial interglacial sea level cycles influence the sr concentration of seawater directly through the periodic exposure and weathering of aragonite on continental shelves and indirectly by modulating the location and extent of carbonate deposition in the ocean as sea level recedes brief pulses of sr are added to the ocean from recrystallization of shelf aragonite this flux at its maximum is nearly ten times larger than the combined riverine and hydrothermal influx the large shelf recrystallization fluxes during glacial maxima produce rapid increases in the sr ca ratio of seawater despite the long residence time of sr in the ocean variations in the ratio of aragonitic vs calcitic sedimentation also influence on the sr content of seawater because the sr partitioning coefficient is higher in aragonite however this effect is minor compared to shelf aragonite recrystallization based on a variety of sensitivity tests the amplitude of sr ca variations ranges from 1 to 3 and is maximized by constant rates of total carbonate deposition extensive aragonite recrystallization and carbonate budgets which include dissolution of shelf carbonates such variation is sufficient to produce up to 1 5 c errors in paleotemperatures calculated from coral sr ca ratios since the last glacial maximum

an assessment of the sr ca ratio in shallow water hermatypic corals as a proxy for sea surface temperature the high precision measurement of the sr ca ratio in corals has the potential for measuring past sea surface temperatures at very high accuracy however the veracity of the technique has been questioned on the basis that there is both a spatial and temporal variation in the sr ca ratio of seawater and that kinetic effects such as the calcification rate can affect the sr ca ratio of corals and produce inaccuracies of the order of 2 4 c in the present study a number of cores of the massive hermatypic scleractinian coral porites from the central great barrier reef have been analyzed for sr ca at weekly to monthly resolution results from a 24 year record from myrmidon reef show an overall variation from 22 7 c to 30 4 c the record shows a warming cooling trend with maximum warming centred on the 1986 1987 summer while some bleaching was reported to have occurred at myrmidon reef in 1982 the sr ca record indicates that subsequent summer temperatures were much higher the 4 5 year record from stanley reef shows a maximum sst of 30 c during the 1997 1998 el nino event the calibrations from myrmidon and stanley reefs are in excellent agreement with previously published calibrations from nearby reefs while corals do not calcify in equilibrium with seawater due to physiological control on the uptake of sr and ca into the lattice of coralline aragonite it can be argued that provided only a single genus such as porites sp is used and that the coral is sampled along a major vertical growth axis then the sr ca ratio should vary uniformly with temperature similarly objections based on the spatial and temporal variability of the sr ca activity ratio of seawater can be countered on the basis that in most areas where coral reefs grow there is a uniformity in the sr ca activity ratio and there does not appear to be a change in this ratio over the growth period of the coral evidence from several corals in this study suggest that stress can be a major cause of the breakdown in the sr ca sst relationship thermal stress resulting from either extremely warm or cool temperatures can produce anomalously low sr ca derived ssts as a result of the breakdown of the biological control on sr ca fractionation it is considered that other stresses such as increased nutrients and changes in light intensity can also lead to a breakdown in the sr ca sst relationship two of the main issues affecting the reliability of the sr ca method are the calibration of the sr ca ratio with measured sst and the estimation of tropical last glacial maximum lgm palaeotemperatures instead of producing a constant calibration just about every one published so far is different from the others what is obvious is that for most calibrations while the slope of the calibration equation is similar the intercepts are not while the cause for this variation is still unknown it would appear that corals from different localities around the world are responding to their own particular environment or that certain types of environments exert a control on the corals physiology sr ca derived sst estimates for the lgm and deglaciation of 5 c 6 c cooler than present are at odds with estimates of 2 c 3 c cooling by other climate proxies the apparent lack of reef growth during the lgm suggests that ssts were too cold in many parts of the tropics for reefs to develop this would lend support to the idea that tropical ssts were much cooler than what the climap data suggests

a 370 000 year record of vegetation and fire history around lake titicaca bolivia peru fossil pollen and charcoal analyses of sediments from lake titicaca peru bolivia provide a record of palaeoclimatic variation spanning four full glacial cycles pollen aquatic microfossils and charcoal as well as previously published data including diatom assemblages carbonate content and stable carbon isotopic ratios of organic carbon indicate that interglacials were warm and dry whereas the peaks of glacials were cold and wet each of the interglacials documented in the record are somewhat different with those of mis 5e and mis 9 inducing lower lake levels and a drier vegetation signature than those of mis 7 and 1 the presence of charcoal particles in sediments deposited during previous interglacials provides evidence of the long term role of fire in shaping andean ecosystems

rise and fall of the paratethys sea during the messinian salinity crisis abstract extremely thick evaporite units were deposited during the so called messinian salinity crisis msc 5 96 5 33 ma in a deep mediterranean basin that was progressively disconnected from the atlantic ocean a crucial but still poorly understood component in messinian evaporite models is the connectivity between mediterranean and paratethys i e the former black sea domain inadequate stratigraphic correlations and insufficient age control for paratethys sediments have so far hampered a thorough understanding of hydrological fluxes and paleoenvironmental changes here we present a new chronology for the eastern paratethys by integrating biostratigraphic and paleomagnetic data from mio pliocene sedimentary successions of romania and russia we show that a major flooding event from the mediterranean surged the paratethys basins at the maeotian pontian boundary 6 04 million years ago this indicates that sea level in both mediterranean and paratethys was high at the beginning of the msc we argue in favor of changes in paratethys mediterranean connectivity to initiate the msc in combination with elusive tectonic processes in the gibraltar arc a subsequent fall of paratethyan water level closely coincides to the mediterranean isolation event corresponding in age to the glacial cycles tg12 14 5 60 5 50 myr in the latest messinian a major climate change towards more humid conditions produced a positive hydrological balance and likely a transgression in the paratethys although our stratigraphic resolution cannot exclude a possible relation to the pliocene flooding of the mediterranean here

late quaternary glaciation and equilibrium line altitudes of the mayan ice cap guatemala central america abstract the sierra los cuchumatanes 3837 m guatemala supported a plateau ice cap and valley glaciers around montana san juan 3784 m that totaled 43 km 2 in area during the last local glacial maximum former ice limits are defined by sharp crested lateral and terminal moraines that extend to elevations of 3450 m along the ice cap margin and to ca 3000 3300 m for the valley glaciers equilibrium line altitudes elas estimated using the area altitude balance ratio method for the maximum late quaternary glaciation reached as low as 3470 m for the valley glaciers and 3670 m for the mayan ice cap relative to the modern altitude of the 0 c isotherm of 4840 m we determined ela depressions of 1110 1436 m if interpreted in terms of a depression of the freezing level during maximal glaciation along the modern lapse rate of 5 3 c km 1 this ela indicates tropical highland cooling of 5 9 to 7 6 1 2 c our data support greater glacial highland cooling than at sea level implying a high tropical sensitivity to global climate changes the large magnitude of ela depression in guatemala may have been partially forced by enhanced wetness associated with southward excursions of the boreal winter polar air mass

late quaternary sea level changes along the tyrrhenian coast near orbetello tuscany central italy palaeoenvironmental reconstruction using ostracods abstract a multidisciplinary study has been carried out on a 51 m long core drilled on coastal lowlands near the albegna river tuscany central italy both sedimentological and faunal analyses ostracods and molluscs indicate a coastal lagoon environment repeatedly influenced both by the rising holocene sea and the albegna river alluvial inflow 13c 18o mg ca sr ca and 87sr 86sr analyses were performed on cyprideis torosa shells in order to detail the influence of albegna river freshwater on the coastal lagoon water the analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings four radiocarbon dates provide a chronostratigraphy for the early holocene part of the core the data are used to reconstruct late pleistocene to early holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial holocene rapid rise in relative sea level an attempt is made to relate sediments and age data from the core to the relative sea level curve for the tyrrhenian sea

refining the eustatic sea level curve since the last glacial maximum using far and intermediate field sites the eustatic component of relative sea level change provides a measure of the amount of ice transferred between the continents and oceans during glacial cycles this has been quantified for the period since the last glacial maximum by correcting observed sea level change for the glacio hydro isostatic contributions using realistic ice distribution and earth models during the last glacial maximum lgm the eustatic sea level was 125 5 m lower than the present day equivalent to a land based ice volume of 4 6 4 9 107 km3 evidence for a non uniform rise in eustatic sea level from the lgm to the end of the deglaciation is examined the initial rate of rise from ca 21 to 17 ka was relatively slow with an average rate of ca 6 m ka 1 followed by an average rate of ca 10 m ka 1 for the next 10 ka significant departures from these average rates may have occurred at the time of the younger dryas and possibly also around 14 ka most of the decay of the large ice sheets was completed by 7 ka but 3 5 m of water has been added to the oceans since that time

holocene coastal change in the ancient harbor of yenikapi istanbul and its impact on cultural history an extensive rescue excavation has been conducted in the ancient harbor of istanbul yenikapi by the sea of marmara revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the holocene the basal layer of this sequence lies at 6 m below the present sea level and contains remains of a neolithic settlement known to have been present in the area indicating that the sea level at 8 9 cal ka bp was lower than 6 m below present sea level advanced to its maximum at 6 8 7 cal ka bp drowning lykos stream and forming an inlet at its mouth after 3 cal ka bp coastal progradation became evident subsequent construction of the byzantine harbor theodosius 4th century ad created a restricted small basin and accumulation of fine grained sediments the sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse grained sediments at the upper parts of the sequence 7th 9th centuries ad the harbor was probably abandoned after the 11th century ad by filling up with lykos stream detritus and continued seaward migration of the coastline

holocene evolution of the haifa bay area israel and its influence on ancient tell settlements the geographical evolution of haifa bay and zevulun plain israel from the late pleistocene to the holocene is based on detailed analysis of drilled cores at the beginning of the holocene the bay area was still under terrestrial conditions only about 9500 to 9000 cal yr bp when sea level rose to about 35 30 m below present sea level b s l did nile derived sand start to bypass the carmel headland and haifa bay come into existence as a morphological feature between 8000 and 7150 cal yr bp when sea level was 14 10 m b s l the invading sea crossed the present day coastline at about 6800 to 6600 cal yr bp sea level rose to about 5 m b s l and flooded the zevulun plain up to 2 km inland and the river qishon estuary up to 4 km inland it is still unknown exactly when the sea reached its maximum penetration inland but later about 4000 years ago the coastline in the research area was still east of the present day coast up to 3 km in the zevulun plain and 4 8 km in the river qishon estuary when the coastline started to retreat westward the reclamation was followed by intensive deposition of shallow marine sand and aeolian dunes while to the east different wetland conditions developed the archaeological data indicate that during the early bronze age i and early bronze age ii dated to between 5600 and 4700 cal yr bp and even later during the middle bronze age ii period about 4600 to 3500 cal yr bp the coastline was still east of the present day coast but it never actually reached the bases of most of the tells as has been suggested except for tel akko and tel abu hawam

how cold were the early permian glacial tropics testing sea surface temperature using the oxygen isotope composition of rigorously screened brachiopod shells abstract brachiopod carbonate from early permian brachiopod shells from low palaeolatitude north iran and higher palaeolatitude pakistan karakorum were screened for diagenesis and analysed for oxygen isotope ratios to derive seawater palaeotemperatures screening techniques employed included sem ultrastructural analysis cathodoluminescence cl image analysis of cl images trace element sr mn fe determinations and carbon and oxygen stable isotope determinations the karakorum shells were found to be diagenetically altered but those from north iran were judged to be pristine using data from pristine material two distinct time slices were analysed the early and middle asselian two contrasting 18 o values for seawater 0 and 1 0 v smow were used to account for different extensions of the gondwanan ice caps the 18 o data from north iran indicate a range of seawater temperatures from 24 3 to 30 3 c for 18 o seawater 0 v smow or from 30 3 to 35 4 c for 18 o seawater 1 0 v smow for the early asselian results for 18 o from the middle asselian indicate seawater temperatures of 24 4 to 28 0 c for 18 o seawater 0 or 29 2 to 32 8 c for 18 o seawater 1 0 the maximum calculated temperatures in the middle asselian are about 2 c lower than those for the early asselian the average temperature for both time slices is similar to modern tropical sea surface temperatures indicating that low latitude early permian ocean waters in iran did not undergo significant cooling during the final glacial iii episode of gondwanan glaciation this confirms other evidence based on biotic provinces which suggests that during the permo carboniferous glaciation the low latitude warm belt became narrower and confined to the western tethys and cathaysian provinces and was not subject to a reduction in temperature but rather a reduction in size

meta analysis of tropical surface temperatures during the last glacial maximum 1 the magnitude of tropical cooling during the last glacial maximum lgm has been the subject of uncertainty for over 25 years we use principles of metaanalysis as an objective approach to reconcile estimates from different proxies this approach treats each observation as a random estimate of the true mean and weights estimates by their reported precision we assigned global uncertainties to proxies and derived a new regional standard deviation for temperatures calculated from the sr ca ratio in tropical corals s 1 4 c using a bayesian spatial interpolation scheme we estimate a mean cooling of lgm tropical sea surface temperatures of 2 7 0 5c s and surface air temperatures of 5 4 0 3c s citation ballantyne a p m lavine t j crowley j liu and p b baker 2005 meta analysis of tropical surface temperatures during the last glacial maximum geophys res lett 32 l05712 doi 10 1029 2004gl021217

identification and environmental interpretation of diagenetic and biogenic greigite in sediments a lesson from the messinian black sea greigite fe3s4 is a widespread authigenic magnetic mineral in anoxic sediments and is also commonly biosynthesized by magnetotactic bacteria in aqueous environments while the presence of fossilized bacterial magnetite fe3o4 has now been widely demonstrated the preservation of greigite magnetofossils in the geological record is only poorly constrained here we investigate mio pliocene sediments of the former black sea to test whether we can detect greigite magnetofossils and to unravel potential environmental controls on greigite formation our magnetic analyses and transmission electron microscope tem observations indicate the presence of both diagenetic and bacterial greigite and suggest a potentially widespread preservation of greigite magnetofossils in ancient sediments which has important implications for assessing the reliability of paleomagnetic records carried by greigite tem based chemical and structural analyses also indicate the common presence of nickel substituted diagenetic iron sulfide crystals with a ferrimagnetic greigite structure in addition our cyclostratigraphic framework allows correlation of magnetic properties of messinian black sea sediments taman peninsula russia to global climate records diagenetic greigite enhancements appear to be climatically controlled with greigite mainly occurring in warm wet periods diagenetic greigite formation can be explained by variations in terrigenous inputs and dissolved pore water sulfate concentrations in different sedimentary environments our analysis demonstrates the usefulness of greigite for studying long term climate variability in anoxic environments key points we provide evidence for the presence of biogenic greigite in ancient sediments diagenetic greigite enhancements are climatically controlled greigite is a paleoenvironmental indicator in anoxic environments

quantitative estimates of orbital and millennial scale climatic variability in central mexico during the last 40 000 years abstract diatom based transfer functions for salinity precipitation and temperature were developed using a training set that included data from 40 sites along central mexico these transfer functions showed good performance parameters and were subsequently applied to the previously published diatom record from lake chalco southern basin of mexico heinrich stadials hs 3 to hs 0 were reconstructed as cold and dry events with hs 2 representing the coldest and driest conditions while hs 1 shows a complex bimodal cooling pattern orbital scale variability is also recorded high and variable lake salinities from 34 to 29 ka bp marine isotope stage 3 mis 3 corresponded with times of maximum summer insolation and evidences of frequent fires mis 2 was identified as a cold period with low lake salinity associated with low evaporation with two cold intervals during the minima in spring 25 5 ka bp and summer 20 ka bp insolation the 20 ka bp cold event together with hs 2 24 23 ka bp defined a bimodal maximum cooling during the last glacial maximum lgm 24 5 19 5 ka bp within the range of pollen based estimates further supporting a maximum tropical cooling of 4 5 c for the lgm the deglacial 19 5 11 5 ka bp showed the highest precipitation anomalies with three peaks that closely correlated with glacier advances in the nearby mountains iztaccihuatl the early holocene marked a change towards high lake salinities and the highest positive temperature anomalies 3 5 c during a peak in summer insolation even though at orbital scale chalco showed a nearly opposite trend to the record from the more southerly lake peten itza guatemala at millennial scale it showed a common pattern of cold and dry conditions during hss comparable to other tropical latitude sites in the northern hemisphere and further supporting the idea that there is a strong coupling between tropical and higher latitudes climates in particular with the north atlantic

magnetostratigraphy and radio isotope dating of upper miocene lower pliocene sedimentary successions of the black sea basin taman peninsula russia abstract we present a new chronology for the upper miocene to pliocene deposits of the black sea basin based on high resolution magnetostratigraphic data coupled with 40 ar 39 ar dating from the 475 m long zheleznyi rog section on the taman peninsula russia this section comprises the stratigraphic interval of the khersonian to kimmerian regional stages of the eastern paratethys our magnetostratigraphic record is based on biogenic and early diagenetic greigite components and yields a magnetostratigraphic sequence of 8 polarity zones a volcaniclastic ash layer at the upper part of the khersonian is radio isotopically dated at 8 69 0 18 ma the age of the khersonian meotian transition arrives at 8 6 or 8 2 ma which is significantly younger than earlier estimates the new age has important consequences for the hipparion datum in the eastern paratethys and implies that all vallesian fossil sites are younger than 11 2 ma the meotian stage has a total duration of 2 2 to maximum 2 6 myr and is marked by multiple erosional events the end of the paratethys sea is dated at 5 5 ma when the black sea becomes isolated from the caspian sea the dacian basin and the mediterranean

harbor areas at ancient troy sedimentology and geomorphology complement homer s iliad for at least two thousand years scholars have debated the location of troy and the events and geographic features described in homer s iliad geologic evidence is used to present a series of maps of the trojan plain that show the geomorphic changes over the past six millennia the geologic evidence correlates very well with the relevant homeric geography

destruction of herod the great s harbor at caesarea maritima israel geoarchaeological evidence geoarchaeological analysis of ancient harbor deposits has answered questions regarding the timing and extent of the destruction of the harbor at caesarea maritima built by herod the great on israel s mediterranean coast by using stratigraphic micropaleontological foraminifera and geochemical sr isotopes analyses of the ancient harbor deposits we can establish a late first to early second century a d date for the destruction of the harbor this destruction occurred earlier was more rapid and widespread than previously proposed and was probably caused by seismic activity the new excavations also indicate that during the fourth to early sixth centuries a d geomorphological processes and siltation within the inner harbor allowed this area to be used in a limited capacity as a harbor

late holocene relative sea level changes in lebanon eastern mediterranean twenty nine 14 c dates of precise biological sea level indicators from the lebanese coast show evidence for two significant regional crustal uplift episodes during the past 6000 years we elucidate 1 an upper shoreline at ca 120 to 140 cm which lasted from ca 6000 to 3000 bp and 2 a lower shoreline at 80 40 cm developed between the fifth century bc and the sixth century ad these movements are associated with 1 two major seismic crises along the yammuneh fault and the roum tripoli thrust rtt and 2 subsequent seismic events on a series of second order ene trending dextral transpressive faults vertical movements affected north lebanon whilst the coasts of south lebanon generally underwent crustal downlift this is in contrast with relative stability in northern israel suggesting an area of stationary tectonic conditions west of the dead sea rosh hanikra ras nakoura fault the main 14 c age cluster corresponding to the second uplift event may have resulted from fault movements during the early byzantine tectonic paroxysm ebtp between ca 1750 and 2000 bp relative sea level stabilised to present level around 1000 bp 2006 elsevier b v all rights reserved

a comparison of pmip2 model simulations and the margo proxy reconstruction for tropical sea surface temperatures at last glacial maximum results from multiple model simulations are used to understand the tropical sea surface temperature sst response to the reduced greenhouse gas concentrations and large continental ice sheets of the last glacial maximum lgm we present lgm simulations from the paleoclimate modelling intercomparison project phase 2 pmip2 and compare these simulations to proxy data collated and harmonized within the multiproxy approach for the reconstruction of the glacial ocean surface project margo five atmosphere ocean coupled climate models aogcms and one coupled model of intermediate complexity have pmip2 ocean results available for lgm the models give a range of tropical defined for this paper as 15 s 15 n sst cooling of 1 0 2 4 c comparable to the margo estimate of annual cooling of 1 7 1 c the models simulate greater sst cooling in the tropical atlantic than tropical pacific but interbasin and intrabasin variations of cooling are much smaller than those found in the margo reconstruction the simulated tropical coolings are relatively insensitive to season a feature also present in the margo transferred based estimates calculated from planktonic foraminiferal assemblages for the indian and pacific oceans these assemblages indicate seasonality in cooling in the atlantic basin with greater cooling in northern summer than northern winter not captured by the model simulations biases in the simulations of the tropical upwelling and thermocline found in the preindustrial control simulations remain for the lgm simulations and are partly responsible for the more homogeneous spatial and temporal lgm tropical cooling simulated by the models the pmip2 lgm simulations give estimates for the climate sensitivity parameter of 0 67 0 83 c per wm 2 which translates to equilibrium climate sensitivity for doubling of atmospheric co2 of 2 6 3 1 c

simulated influence of carbon dioxide orbital forcing and ice sheets on the climate of the last glacial maximum a coupled atmosphere ocean sea ice model is used to investigate the climate of the last glacial maximum 21 000 years ago and the relative climate forcing effects of atmosphere co2 the earth s orbital parameters and ice sheet albedo tropical temperatures are found to be 2 2 c less than today s slightly colder than indicated by the climap palaeoclimate reconstruction this result is consistent with a low to medium climate sensitivity to radiative perturbations temperatures are colder still in the northern north atlantic region owing to a weakening and shallowing of the thermohaline circulation a sensitivity analysis suggests that changes in ocean circulation since the last glacial maximum have not contributed directly to the global mean temperature change since that time

late neogene evolution of the taza guercif basin rifian corridor morocco and implications for the messinian salinity crisis abstract magnetostratigraphic and biostratigraphic results are presented from neogene deposits in the taza guercif basin located at the southern margin of the rifian corridor in morocco this corridor was the main marine passageway which connected the mediterranean with the atlantic during messinian times correlation of the biostratigraphy and polarity sequence of the taza guercif composite section to the astronomical time scale allows an accurate dating of three subsequent events in the rifian corridor 1 the oldest marine sediments marking the opening of the rifian corridor were deposited at 8 ma at this age a deep 600 m marine basin developed in the taza guercif area marked by deposition of precession controlled turbidite marl cycles 2 paleodepth reconstructions indicate that a rapid 5 m ka shallowing of the marine corridor took place at the tortonian messinian boundary at an age of 7 2 ma this shallowing phase is primarily related to active tectonics although a small glacio eustatic sea level lowering also took place 3 the taza guercif basin was emergent at an age of 6 0 ma and subsequently continental sedimentation continued well into the early pliocene we suggest that shallowing and restricting the marine passageway through the rifian corridor actually initiated the messinian salinity crisis well before the deposition of the messinian evaporites in the mediterranean

holocene palaeogeographies of the astakos coastal plain akarnania nw greece abstract this paper deals with holocene coastal changes of the astakos plain in akarnania nw greece palaeoenvironmental scenarios are based on the analysis of the lateral and vertical distribution patterns of sedimentary facies sediments from vibracorings were studied using geomorphological sedimentological microfaunal palaeobotanical and geochemical methods a geochronostratigraphy was achieved by 14c ams dating of organic matter we present palaeogeographical maps for different points in time since the mid holocene the evolution of the coastal area was generally controlled by the migration of a complex system of a shallow marine embayment an adjacent lagoonal environment and an adjoining coastal lake forced by the interaction of sea level rise tectonic movements and sediment supply from the hinterland the maximum transgression of the ionian sea took place at circa 5500 cal bc reaching approx 1 1 km inland the lagoon as well as the coastal lake had their largest dimensions around 4500 cal bc indicating a more humid climatic period in the course of a long lasting regression an asymmetric sedimentation pattern developed around 2500 cal bc it was characterized by strong fluvial deposition of the xeropotamos in the western plain and a small and narrow marine embayment with associated lagoonal to limnic coastal water bodies in the eastern plain the latter were related to karstic springs draining the adjacent rigani ridge around 500 cal bc the coastline lay about 200 m landward of its present position possible harbour sites for the ancient polis of astakos are a the area of modern astakos where a mole in a position seawards of the present coast would have guaranteed deep water conditions for anchoring or b the southeastern fringe of the plain where deep water prevailed and the nearby freshwater outlet protected the site from rapid siltation we found increased torrential activity i for the 6th 5th millennium bc ii for the 2nd half of the 1st millennium bc until roman times and iii at the end of the 19th century ad at least the two younger phases are mostly due to anthropogenic soil erosion between the 4th and the 2nd millennium bc a period of ecological stability existed relative changes in sea level for the bay of astakos were reconstructed for the first time since the mid holocene the relative sea level has never reached a higher position than today it rose from 12 50 m b s l at 6200 cal bc via 2 20 m b s l at 500 cal bc to its present level besides eustatic reasons tectonic subsidence due to the half graben structure of the area is the main trigger of the relative rise in sea level

deformation along the yammuneh the restraining bend of the dead sea transform paleomagnetic data and kinematic implications a simple geometrical model shows that the plate margin along the restraining bend segment of the transform plate boundary be deformed in order to accommodate overlap of the crust this model predicts both the maximum width of the deformed zone and the magnitude of deformation when the general geometry of the plate margin is known as well as the plate slip vector and the amount of cumulative displacement this idea has been tested along the plate margin of the yammuneh restraining bend of the dead sea transform the plate margin has been deformed by nne folding parallel to the restraining bend and by east west trending right lateral strike slip faults paleomagnetic measurements yield counterclockwise rotation of r r 61 0 9 6 and f f 23 4 17 2 the paleomagnetic rotational data and fault kinematic suggest that the mechanism which accommodates regional left lateral shear is simultaneous right lateral strike slip faulting on secondary faults and block rotation the magnitude of deformation is the same as that predicted by the model which is 100 shortening in a direction parallel to the plate slip vector and negligible deformation in a direction parallel to the transform the large amount of rotation implies that probably more than one fault set is involved and present day seismic activity is the current manifestation of this crustal deformation process if this prediction is correct then the current deformation of the plate margin is accommodated by more favorable newly formed nnw right lateral strike slip faults

oxygen and carbon stable isotope records of the lochkovian pragian boundary interval from the prague basin lower devonian czech republic abstract climate changes close to the lochkovian pragian event are still widely discussed carbonate 18o and 13c and conodont apatite 18o from medial to distal carbonate ramp sediments were analysed to provide further stable isotope data from the stratotype area in the prague basin the uppermost silurian to lower emsian 18o trends are put into an updated conodont biostratigraphy framework carbonate 18o and 13c are discussed in the context of facies dependent diagenesis the 13c pattern measured from different sections enables the correlation of intervals with development of different facies inside the prague basin positive 13c shifts are often coupled with trends of decreasing computed gamma ray cgr values interpreted as regressions whereas negative 13c shifts commonly coincide with opposite trends in cgr the lochkovian pragian boundary interval coincided with an increase in carbonate 13c and an increase in the 18o of conodont apatite and carbonate which we interpret as consequence of climate cooling generally the lochkovian was warmer than the pragian and earliest emsian