variability of the north atlantic thermohaline circulation during the last interglacial period studies of natural climate variability are essential for evaluating its future evolution greenland ice cores suggest that the modern warm period the holocene has been relatively stable for the past 9 000 years much less is known about other warm interglacial periods which comprise less than 10 of the climate record during the past 2 5 million years here we present high resolution ocean sediment records of surface and deep water variables from the bermuda rise spanning the last interglacial period about 118 000 127 000 years ago in general deep water chemical changes are coincident with transitions in surface climate at this site the records do not show any substantial fluctuations relative to the much higher variability observed during the preceding and subsequent cool climates the relatively stable interglacial period begins and ends with abrupt changes in deep water flow we estimate using 230 th measurements to constrain the chronology that transitions occur in less than 400 years

experimental modeling of horizontal and vertical wave forces on an elevated coastal structure abstract a large scale physical model was created in oregon state university s large wave flume to collect an extensive dataset measuring wave induced horizontal and vertical forces on an idealized coastal structure water depth was held constant while wave conditions included regular irregular and transient tsunami like waves with different significant wave heights and peak periods for each test the elevation of the base of the test specimen with respect to the stillwater depth air gap was also varied from at grade to 0 28 m above the stillwater level to better understand the effects of raising or lowering a nearshore structure on increasing or decreasing the horizontal and vertical wave forces results indicate that while both horizontal and vertical forces tend to increase with increasing significant wave height the maximum and top 0 4 of forces increased disproportionally to other characteristic values such as the mean or top 10 as expected the horizontal force increased as the test specimen was more deeply submerged and decreased as the structure was elevated to larger air gaps above the stillwater level however this trend was not true for the vertical force which was maximized when the elevation of the base of the structure was equal to the elevation of the stillwater depth small wave heights were characterized by low horizontal to vertical force ratios highlighting the importance of considering vertical wave forces in addition to horizontal wave forces in the design of coastal structures the findings and data presented here may be used by city planners engineers and numerical modelers for future analyses informed coastal design and numerical benchmarking to work toward enabling more resilient nearcoast structures

deep sea biostratigraphy of prograding platform margins neogene bahamas key evidence linked to depositional rhythm abstract new foraminiferal evidence from two boreholes on the paleoshelf and slope of western great bahama bank has wide ranging implications for understanding formation and evolution of carbonate platform margins the new data abundant well preserved planktic foraminifera were obtained by disaggregating samples from intercalated pelagic layers and selected parts of thick hemipelagic limestone earlier efforts to obtain biostratigraphic ages identified six biostratigraphic units in each borehole provided biozonal age alternatives for both holes and resulted in different pliocene biozones between them the new data define six units in one hole and seven in the other bracket the biozones present and their ages indicate different sedimentation rates and show that within the limits of biostratigraphic resolution the biozones are correlative between the holes most importantly the revised ages show that the paleoshelf borehole probably penetrated the late miocene rather than middle miocene the oldest unit is on the paleoshelf and the youngest uppermost pliocene is on the slope between the holes the stratigraphic interval spans the temporal interval from an inferred maximum of 10 2 ma to a minimum of 1 6 ma although the biozones range sequentially from the neogloboquadrina acostaensis n16 zone to the basal part of the globorotalia truncatulinoides truncatulinoides n22 zone globorotalia crassaformis viola subzone absence of key species indicates that deposition was discontinuous numerous periods of erosion and or nondeposition are inferred the largest of which is a condensed section hiatus 1 2 myr above the paleoslope miocene pliocene boundary in addition the late pliocene globorotalia tosaensis tosaensis n21 zone is not recognized on the slope its absence is consistent with a widespread regional unconformity sedimentation rates and depths of series boundaries vary widely in both holes the paleoslope miocene pliocene boundary lies at 540 m below top of the hole the lower upper pliocene boundary is placed at or near 444 m position of the pliocene pleistocene boundary is less certain but is within the top 382 m of the hole its placement anywhere within this interval is a reasonable assessment considering an exceptionally high rate of sedimentation 562 m myr 168 6 m interval based on topmost foraminiferal sample 1 9 1 6 ma as expected the lowest sedimentation rate occurs in the condensed section overlying the miocene pliocene boundary 5 m myr 9 5 m 5 3 4 1 ma the paleoshelf miocene pliocene boundary lies below a hiatal condensed section 295 278 m below top of the hole that has a greater sedimentation rate 89 m myr 17 7 m 5 5 5 3 ma than that at the slope the lower upper pliocene boundary is placed at or near a depth of 236 m and the pliocene pleistocene boundary lies within the top 113 m of the hole sedimentation rates on the shelf range from 15 m myr above the condensed section 22 9 m 5 3 3 8 ma to a late pliocene high of 183 m myr 54 9 m interval based on the point at which the age depth line crosses the 1 9 myr mark between the topmost two fossiliferous samples 2 2 1 9 ma

insolation values for the climate of the last 10 million years new values for the astronomical parameters of the earth s orbit and rotation eccentricity obliquity and precession are proposed for paleoclimatic research related to the late miocene the pliocene and the quaternary they have been obtained from a numerical solution of the lagrangian system of the planetary point masses and from an analytical solution of the poisson equations of the earth moon system the analytical expansion allows the direct determination of the main frequencies with their phase and amplitude numerical and analytical comparisons with the former astronomical solution ber78 are performed so that the accuracy and the interval of time over which the new solution is valid can be estimated the corresponding insolation values have also been computed this analysis leads to the conclusion that the new values are expected to be reliable over the last 5 ma in the time domain and at least over the last 10 ma in the frequency domain

tsunami evolution and run up in a large scale experimental facility abstract in this paper we study the propagation and run up of long tsunami like waves in the 300 m long large wave flume gwk hannover germany and analyze the feasibility of experiments on tsunami run up in large facilities this paper is the continuation of our previous paper schimmels et al 2015 companion paper the propagation of long period waves over large distances for different shapes is studied experimentally and numerically fully nonlinear potential flow theory has been used to model these cases numerically along with korteweg de vries simulations the theoretical explanation of the observed effects has been discussed the run up characteristics of the studied waves with respect to their shape and beach slope were also investigated further a downscaled real tsunami time series is also reproduced experimentally and studied with regard to its possible run up

the 11 march 2011 east japan earthquake and tsunami tsunami effects on coastal infrastructure and buildings the 11 march 2011 east japan earthquake and tsunami caused unprecedented damage to well engineered buildings and coastal structures this report presents some notable field observations of structural damage based on our surveys conducted along the sanriku coast in april and june 2011 engineered reinforced concrete buildings failed by rotation due to the high velocity and deep tsunami inundation entrapped air in the buildings and soil liquefaction by ground shaking could have contributed to the failure the spatial distribution pattern of destroyed and survived buildings indicates that the strength of tsunami was affected significantly by the locations of well engineered sturdy buildings weaker buildings in the shadow zone tended to survive while jet and wake formations behind the sturdy buildings enhanced the tsunami forces we also found that buildings with breakaway walls or breakaway windows doors remained standing even if the surrounding buildings were washed away or destroyed several failure patterns of coastal structures seawalls were observed flow induced suction pressure near the seawall crown could have caused the failure of concrete panels that covered the infill remarkable destruction of upright solid concrete type seawalls was closely related with the tsunami induced scour and soil instability the rapid decrease in inundation depth during the return flow phase caused soil fluidization down to a substantial depth this mechanism explains severely undermined roads and foundations observed in the area of low flow velocities

what is what in the ice and the ocean recently released data from the north greenland ice core project ngrip document several rapid abrupt climate changes affecting the northern hemisphere in the last 110 000 years in particular the new core shows high resolution succession of expressed warm and cold episodes which occurred during substages of marine isotope stage mis 5 some of these variations were reported earlier from the gisp2 and grip ice cores in the ngrip core following the intimate group recommendations the oscillations were given labels which are in part the same as in the isotope system of deep sea sediments although to some extent they are not coeval here we recommend honoring the originally published marine designations wherever possible but distinguishing them by a prefix referring to their recognition in the ice

linking the vicissitude of neolithic cities with mid holocene environment and climate changes in the middle yangtze river china abstract this study investigated fifteen neolithic cities distributed in a crescent shaped belt along the middle yangtze river from the period between 4750 and 3050 bc 6 7 5 0 cal ka bp the belt consists of a low lying medial alluvial plain surrounded by hills more than 50 m a s l above sea level the neolithic cities within this belt occupied three distinct topographies the highlands of alluvial plains the lower foothills and the surrounding hills all the cities were situated adjacent to the lowest level tributaries or smallest lakes and had complex trench defense systems with rivers and lakes interlinking the trenches and most of the cities had defensive moats construction peaks of defensive fortifications occurred during the daxi 4550 3050 bc and qujialing cultures 3050 2650 bc while most neolithic cities were abandoned in the late shijiahe period 2250 bc based on assessments on the locality age construction and the detailed information on the geographical characteristics of the neolithic cities the sites of neolithic cities were tightly associated with the development history of east civilization and the rise of the cities is well correlated with the warm and humid climate in mid holocene 5 2 cal ka bp or 3250 bc while the decline of the ancient cities is related with the dry and cold climate in mid late holocene 4 2 cal ka bp or 2250 bc the development and decline of these cities were also well linked with water accessibility topography and the occurrence of droughts floods and other extreme events during the mid holocene such environment conditions and climate changes played significant roles for the ancient people to determine the location structure and morphology of the cities although the military considerations were also important we cannot simply consider the prehistoric city construction in the middle yangtze river was a passive defense against foreign invasion

reconstruction of the grande pile eemian using inverse modeling of biomes and δ13c abstract a new method to reconstruct past climatic conditions between 130 and 100 ka bp from pollen and isotopic data is applied to a previously unanalyzed grande pile core gpxxi we applied the inverse mode to the biome4 vegetation model the method utilizes 13 c measured in parallel to the pollen samples as a constraint for the model first the biomes and the 13 c simulated by the model are compared with the biome allocation of the pollen data the 13 c to be simulated takes into account the degradation effect on the preserved organic matter this procedure allows the reconstruction of the mean annual temperature and precipitation as well as the mean temperatures of the warmest and coldest months we show that during the eemian sensu stricto the reconstructed precipitation is similar to modern values with low variability the cold stadials and the penultimate glaciation are characterized by very low precipitation amounts the temperature estimates however indicate differences with several oscillations identified the peak values are reached at about 124 125 ka bp but two other warm intervals are also identified the variations in temperature appear to be related to sea surface temperature oscillations in the north atlantic region and are also in agreement with the timing of ice sheet build up in the northern hemisphere seasonal variations are also identified in the estimated temperatures of the warmest and coldest months

sea level and climate changes during ois 5e in the western mediterranean palaeontological geomorphological and sedimentological data supported by isotopic dating on oxygen isotopic stage ois 5e deposits from the spanish mediterranean coast are interpreted with the aim of reconstructing climatic instability in the northern hemisphere data point to marked climatic instability during the last interglacial ois 5e with a change in meteorological conditions and consequently in the sedimentary environment the oolitic facies generated during the first part of ois 5e ca 135 kyr shift into reddish conglomeratic facies during the second part ca 117 kyr sea surface temperature sst and salinity are interpreted mainly on the basis of warm senegalese fauna which show chronological and spatial differential distribution throughout the western mediterranean present hydrological and meteorological conditions are used also as modern analogues to reconstruct climatic variability throughout the last interglacial and this variability is interpreted within the wider framework of the north atlantic record all the available data indicate an increase in storminess induced by an increase in the influence of northwesterlies a slight drop of sst in the northern western mediterranean and an important change in meteorological conditions at the end of ois 5e 117 kyr these changes correlate well with the decrease in summer insolation and with the climatic instability recorded in north atlantic high latitudes

microfossil biostratigraphy of prograding neogene platform margin carbonates bahamas age constraints and alternatives abstract benthic and planktic foraminifera and calcareous nannofossils were recovered in shallow water carbonate rock cores from two continuous boreholes drilled 7 5 km apart on the west platform margin of the great bahama bank the microfossils define six biostratigraphic units in each hole one unit in each hole represents a correlative condensed section seven foraminiferal biozones are recognized in 11 of the units between the holes middle miocene globorotalia fohsi robusta zone n12 late miocene g acostaensis zone n16 and g humerosa zone n17 early pliocene g margaritae evoluta subzone n19 late pliocene g exilis subzone n21 and tentatively g tosaensis tosaensis zone n21 and early pleistocene g crassaformis viola subzone n22 the twelfth unit is inferred to be of g crassaformis viola subzone n22 age the oldest unit is onshore the youngest is offshore as presently interpreted the nannofossil and foraminiferal zonations are partially correlative although the microfossils unequivocally constrain the series ages of the sediments the incompleteness of the fossil record allows for alternative biozonal age models within the series the miocene and pliocene biozones are common to both holes but the greatest similarities between the holes are the significant mixing of middle and late miocene and late miocene early pliocene faunas the greatly condensed intervals at the miocene pliocene boundary and the early pliocene influx of deep water benthic and pelagic foraminifera of particular importance is the tentative recognition of late pliocene g tosaensis tosaensis zone n21 in one borehole subsequent data not available to this phase of the study indicate that much of the zone is likely missing its absence will lend support to speculations of a regional unconformity in the bahamas the microfossils indicate that 1 several transgressions occurred from the middle miocene to at least the earliest pleistocene 11 5 0 46 ma during which banktop derived sediments accumulating at the margin prograded the platform seaward 2 a condensed interval on the bank top may represent a late miocene lowstand a period of sediment bypassing or a lack of accommodation space 3 the slope received thin layers of pelagic sediments in a condensed interval during the late miocene and early pliocene while the bank top accommodated early pliocene 4 2 3 4 ma deep water indicators prior to a likely period of exposure 2 35 1 89 ma 4 two cycles of banktop sediment production and starvation occurred during the pliocene 5 the pliocene transgression was punctuated by stillstands or low amplitude reversals during which parts of biozones did not accumulate and 6 the sediments containing the most complete microfossil datum record are the thin pelagic strata that mark interruptions in the regular shedding of transgressive deposits from the platform sedimentation rate patterns varied but were generally higher offshore than onshore

high resolution climate records from the north atlantic during the last interglacial the two deep ice cores recovered by the grip1 and gisp22 projects at summit greenland agree in detail over the past 100 000 years3 and demonstrate dramatic climate variability in the north atlantic region during the last glacial before the current period of holocene stability this glacial climate instability has subsequently been documented in the marine sedimentary record of surface ocean conditions in the north atlantic4 before 100 kyr ago the two ice core records are discrepant however casting doubt on whether the oxygen isotope fluctuations during the last interglacial eemian seen in the grip core1 5 represent a true climate signal here we present high resolution records of foraminiferal assemblages and ice rafted detritus from two north atlantic cores for the interval 65 kyr to 135 kyr ago extending the surface ocean record back to the eemian the correlation between our records and the greenland ice core records is good throughout the period in which the two ice cores agree suggesting a regionally coherent climate response during the eemian our marine records show a more stable climate than that implied by the grip ice core suggesting that localized phenomena may be responsible for the variability in the latter record during the eemian

insights into north atlantic deep water formation during the peak interglacial interval of marine isotope stage 9 mis 9 foraminifera abundance and stable isotope records from odp site 984 61 25 n 24 04 w 1648 m in the north atlantic are used to reconstruct surface circulation variations and the relative strength of the north atlantic deep water nadw formation over the period spanning the peak warmth of marine interglacial stage mis 9e 324 336 ka this interval includes the preceding deglaciation termination 4 t4 and the subsequent glacial inception of mis 9d the records indicate a greatly reduced contribution of nadw during t4 as observed in more recent deglaciations in contrast with the most recent deglaciation the lack of a significant nadw signal extended from t4 well into the peak interglacial mis 9e and persisted nearly until the transition to the subsequent glacial stage mis 9d although nadw formation resumed during mis 9e only depths greater than 2000 m appear to have been ventilated the poorly ventilated intermediate depth of site 984 2000 m may have resulted on one hand from a general reduction of deep water ventilation by nadw during the study interval or on the other hand from different pathways of the spread of newly formed nadw that bypassed the study location the intermediate depths may have also been invaded by southern sourced waters as the formation of intermediate depth nadw weakened the absence of any significant nadw signal at the water depth of site 984 during the climatic optimum contrasts sharply with subsequent interglacial peaks mis 5e and the holocene despite the perturbed intermediate depth circulation oceanic heat transport northeastward was not interrupted and may have contributed to the relatively mild interglacial conditions of mis 9e

interglacials of the last 800 000 years interglacials including the present holocene period are warm low land ice extent high sea level end members of glacial cycles based on a sea level definition we identify eleven interglacials in the last 800 000 years a result that is robust to alternative definitions data compilations suggest that despite spatial heterogeneity marine isotope stages mis 5e last interglacial and 11c 400 ka ago were globally strong warm while mis 13a 500 ka ago was cool at many locations a step change in strength of interglacials at 450 ka is apparent only in atmospheric co2 and in antarctic and deep ocean temperature the onset of an interglacial glacial termination seems to require a reducing precession parameter increasing northern hemisphere summer insolation but this condition alone is insufficient terminations involve rapid nonlinear reactions of ice volume co2 and temperature to external astronomical forcing the precise timing of events may be modulated by millennial scale climate change that can lead to a contrasting timing of maximum interglacial intensity in each hemisphere a variety of temporal trends is observed such that maxima in the main records are observed either early or late in different interglacials the end of an interglacial glacial inception is a slower process involving a global sequence of changes interglacials have been typically 10 30 ka long the combination of minimal reduction in northern summer insolation over the next few orbital cycles owing to low eccentricity and high atmospheric greenhouse gas concentrations implies that the next glacial inception is many tens of millennia in the future

late neogene planktonic foraminiferal biostratigraphy and climatostratigraphy of the solo river section java indonesia abstract paleoclimate changes are reconstructed from late miocene earliest pleistocene deep water sediments of the solo river section using fluctuations in planktonic foraminiferal faunas water depth and clastic influx intervals with common cold water planktonics globigerina bulloides neogloboquadrina cf pachyderma are thought to reflect periods of increased upwelling triggered by antarctic glaciations correlations with well bodjonegoro 1 java dsdp site 62 1 and lamont core rc 12 66 equatorial pacific using planktonic foraminiferal datum levels and paleoclimate trends suggest non synchroneity of several commonly used datums probably due to differences in species concepts it also allowed dating of the climate changes with regard to the magnetostratigraphic and numerical time scales for correlations between different faunal provinces global climate changes are an extremely useful tool probably superior to any single faunal datum using this with other evidence the following correlations could be obtained between the five climatostratigraphic zones in the solo river section and the mediterranean and new zealand stages from bottom to top 1 zone i samples sr 63 sr 53 cool older than 6 0 m y 5 8 m y magnetostratigraphic epoch 6 and older basal epoch 5 planktonic zone upper n16 n17 mediterranean stages upper tortonian early messinian new zealand stages tongaporutuan early kapitean late miocene 2 zone ii sr 52 sr 35 moderately warm with fluctuations 5 8 m y 5 0 m y epoch lowermost gilbert upper n17 n18 late messinian evaporite phase late kapitean late miocene 3 zone iii sr 34 sr 33 cool 5 0 4 8 m y within lower gilbert n18 basal n19 latest messinian lago mare phase latest kapitean or earliest opoitian latest miocene 4 zone iv sr32 sr 18 warm to very warm 4 8 2 7 m y within lower gilbert within upperg gauss n19 within n21 zanclean piacenzian opoitian pliocene 5 zone v sr17 sr 12 cool 2 7 m y age of top unknown upper gauss lower matuyama within n21 n22 santernian or basal calabrian s l waipipian basal pleistocene late pliocene of workers with different pliocene pleistocene boundary concepts

phase relationships between millennial scale events 64 000 24 000 years ago a core recovered on the iberian margin off southern portugal can be correlated with greenland ice cores using oxygen isotope variability in planktonic foraminifera which closely matches the ice core records of temperature over greenland our age model identifies the base of every interstadial between 64 000 and 24 000 years ago and uses the greenland ice core project grip timescale the oxygen isotope signal in benthic foraminifera on this grip based timescale is quite different from the planktonic record and resembles the temperature record over antarctica when this is synchronized with greenland using the record of methane in the atmospheric air in the polar ice cores we interpret the benthic record as indicating significant fluctuations in ice volume during millennial events and we suggest that antarctic temperature changed as a function of ice volume

quantitative analysis of quaternary nannoplankton in the subtropical northwestern pacific ocean abstract time progressive changes of nannoflora and biometry of coccoliths for the last 1 3 m y were investigated for a piston core recovered from the west mariana ridge the species compositions were quantitatively investigated under an electron microscope and six assemblages assemblages a through f were identified significant changes in relative abundances of various types of genus gephyrocapsa are the main cause for the stratigraphic change of the flora a dominant occurrence of gephyrocapsa protohuxleyi var a which can be identified only under an electron microscope was observed for the first time in a thin sequence which corresponds to the lowest part of the brunhes epoch 0 75 0 62 ma because of this characteristic occurrence assemblage d was further subdivided into three subassemblages the dominant occurrence of small gephyrocapsa which is well known in the small gephyrocapsa zone of the equatorial pacific ocean was not observed but the almost complete absence of medium to large gephyrocapsa during approximately 200k years of the middle pleistocene was confirmed a stratigraphically restricted occurrence of a large form of reticulogenestra was also confirmed by the biostratigraphic study under a light microscope and the last and first occurrences of the largest form reticulofenestra sp a 6 5 m were identified at 0 81 and 0 98 ma respectively in addition to these four events precise ages for another five well known evolutionary events were also calibrated these ages are generally in good agreement with previously reported ages from other world oceans and diachronism was not evident for most of these evolutionary events

a north atlantic tephrostratigraphical framework for 130 60 ka b2k new tephra discoveries marine based correlations and future challenges abstract building chronological frameworks for proxy sequences spanning 130 60 ka b2k is plagued by difficulties and uncertainties recent developments in the north atlantic region however affirm the potential offered by tephrochronology and specifically the search for cryptotephra here we review the potential offered by tephrostratigraphy for sequences spanning 130 60 ka b2k we combine newly identified cryptotephra deposits from the ngrip ice core and a marine core from the iceland basin with previously published data from the ice and marine realms to construct the first tephrostratigraphical framework for this time interval forty three tephra or cryptotephra deposits are incorporated into this framework twenty three tephra deposits are found in the greenland ice cores including nine new ngrip tephras and twenty separate deposits are preserved in various north atlantic marine sequences major minor and trace element results are presented for the new ngrip horizons together with age estimates based on their position within the ice core record basaltic tephras of icelandic origin dominate the framework with only eight tephras of rhyolitic composition found new results from marine core md99 2253 also illustrate some of the complexities and challenges of assessing the depositional integrity of marine cryptotephra deposits tephra based correlations in the marine environment provide independent tie points for this time interval and highlight the potential of widening the application of tephrochronology further investigations however are required that combine robust geochemical fingerprinting and a rigorous assessment of tephra depositional processes in order to trace coeval events between the two depositional realms

reworked paleogene to early neogene planktic foraminifera implications of an intriguing distribution at a late neogene prograding margin bahamas abstract a rich uniquely distributed assemblage 80 species of reworked paleogene to early neogene 66 15 ma planktic foraminifera is documented within 470 m of late neogene 5 7 1 6 ma borehole limestone from the great bahama bank west margin tests vary in size from 0 13 to 1 0 mm and are unusually well preserved where obtainable from the rock the relict species constitute an estimated 20 to 50 of all taxa paleocene faunas occur in upper miocene host rocks eocene species occur in upper miocene and basal upper pliocene rocks and mixed oligocene and early miocene taxa occur throughout the section including the uppermost pliocene i e the oldest groups disappear successively uphole each host rock interval is separated by major disconformities this record provides a substantial proxy for 1 a probable source feature an epipelagic marine tectonic wall escarpment or outcrop composed of pelagic and hemipelagic sediments 2 a probable tectonically active source area northern cuba or southern bahamas and 3 a variety of events that span 60 myr and have wide ranging implications from local progressive isolation of the oldest faunas to regional changes in water depth indicated by the faunas to global hiatuses that correlate with one or more major sequence boundaries in the atlantic bahamas and gulf of mexico as well as proposed eustatic lowstands seven unidentified foraminiferal biozones correspond to a proposed early eocene composite condensed section on the eustatic curve and may have regional implications the relict faunas also have significant implications for the timing and types of paleogene and early neogene sedimentation or nondeposition sea level fluctuations slumping or changing depth of effective marine erosion and regional late neogene events that occurred over 4 myr age of host rocks the direction of the source area from the secondary emplacement site and the estimated percentages of relict faunas indicate that not all the microfossils in the late neogene borehole sediments and by extrapolation therefore along the entire west margin of the platform were locally derived the amount of a possible attendant sedimentary component is not known

duration of last interglacial conditions in northwestern greece a new astronomical calibration method for long pollen records from southern europe is applied to the last interglacial interval of the ioannina sequence northwest greece this shows that the last interglacial in this region as defined by the presence of forest communities lasted c 15 500 years from 127 300 to 111 800 yr b p interglacial conditions developed within marine isotope sub stage mis 5e and persisted into mis 5d lagging changes in global ice volume

a late quaternary marine palynological record oxygen isotope stages 1 to 7 for the humid tropics of northeastern australia based on odp site 820 a late quaternary marine palynological record from the ocean drilling program odp site 820 adjacent to the humid tropics region of northeastern australia has demonstrated marked variation in orbital scale cyclicity and also trends associated with both climate and human impact however some uncertainties in interpretation have resulted from concerns about the records chronology and continuity here we present for the first time the complete palynological data from detailed analysis of the top 67 m of sediment and examine it in relation to the marine isotope sequence from the core it is proposed that the record is relatively continuous through the last 250 000 years although the latter part of oxygen isotope stage ois 5 as well ois 4 may be missing despite the variation on orbital scales most palynological changes are not in phase with those from the marine isotope record suggesting a lack of direct milankovitch forcing on vegetation this lack of correspondence combined with major trends towards more open and sclerophyllous vegetation in association with increased burning supports a previous proposal that major control is being exercised by el nino southern oscillation variability whose influence may have been initiated by changes in oceanic circulation in the region within the mid pleistocene the lack of impact on the distribution of complex rainforest suggests that increased climate variability did not involve an overall decrease in total precipitation c 2007 elsevier b v all rights reserved

the demise of the last interglacial recorded in isotopically dated speleothems from the alps abstract the transition from interglacial to glacial climate has attracted much attention in paleoclimatic research partly because orbital forcing dictates that such a return to a new ice age is inescapable albeit in the distant future only the detailed series of steps that leads to glacial inceptions remains poorly understood however and studies of past glacial inceptions are often compromised by incomplete records imprecise chronological control and or uncertainties associated with proxy transfer functions here we present results from u th dated speleothems from a cave in the austrian alps entrische kirche cave which grew continuously between ca 127 and 114 ka and intermittently also during subsequent stadials and interstadials the alpine setting of this cave is prone to periglacial and glacial processes as well as temperature and precipitation changes which are recorded in these cave deposits we use high resolution stable isotope data to constrain paleoenvironmental changes associated with the demise of the last interglacial unprecedented in detail for central europe peak interglacial conditions are characterized by high 18 o values and high growth rates from ca 127 to 124 ka a major drop in 18 o by 3 occurred at ca 118 ka which coincided with cold event c26 in the north atlantic this isotopic shift which occurred at or close to isotopic equilibrium cannot be explained by simple uniform cooling modelling suggests that enhanced seasonality dominated by significant changes in winter precipitation are required to reconcile the isotope data with the fact that calcite deposition continued across the mis 5e d transition i e no cave freezing this period of enhanced seasonality lasted for several millennia during which the catchment area of the cave remained geomorphologically stable and ice free eventually speleothem growth terminated at ca 114 ka which is in line with widespread ice rafting in the north atlantic cold event c24 and the onset of fully stadial conditions during mis 5d

global ice volume fluctuations north atlantic ice rafting events and deep ocean circulation changes between 130 and 70 ka multiproxy data from north atlantic deep sea sediment core neap18k provide a detailed record of climate through oxygen isotope stage ois 5 seven distinct large scale episodes of ice rafting c25 c19 were identified between 126 and 70 ka global ice volume reconstructions based on high resolution benthic 18 o records indicate that major ice rafting events were not confined to ice volume maxima at ois 5d and 5b but also occurred during periods of ice sheet growth and disintegration however iceberg discharges were restricted to times when sea levels were 40 65 m below present values ice rafting episode c25 the first large scale cooling of mid atlantic surface waters after the last interglacial occurred during the gradual buildup of continental ice sheets at the ois 5e 5d transition major ice sheet collapses allied to ice rafting events c24 and c21 were associated with rapid sea level increases of 20 and 40 m respectively suborbital climatic fluctuations in the neap18k sedimentary record denoted by prominent 7 5 4 5 and 3 k y cyclicities appear to correlate with both greenland atmospheric temperatures and changes in thermohaline circulation patterns inferred from benthic 13 c values and hence provide clear evidence of a highly interconnected north atlantic climatic regime during ois 5

mis 5a and mis 3 relatively high sea level stands on the hatay samandag coast eastern mediterranean turkey abstract the coastal belt of hatay samandag in the east mediterranean is marked by the intersection of the african arabian and eurasian anatolian platelet plates where several quaternary shorelines related to relative sea level changes can be seen above the current sea level in this study the most common and best preserved high sea level markers of the marine isotope stage mis 5 and mis 3 shorelines were dated for the first time using the mollusc based electron spin resonance esr method as a result of this research the age of the late mis 5 and mis 3 sea level highstands in the eastern mediterranean the elevation of the corresponding shoreline at samandag coast and the vertical component of the late quaternary tectonic movements which has an impact on shoreline were determined the shorelines at 48 43 m elevations between cevlik and samandag at 58 6 m in tekebasi and at 21 m at keldag have been dated to approximately 72 ka and therefore are correlated with mis 5a the shoreline at 40 39 m elevations between cevlik and samandag has been dated to approximately 53 ka and therefore is correlated with mis 3 according to the position of the mis 5a shorelines the uplift rate over the last 72 ka was 0 88 mm y between cevlik and samandag 1 08 mm y in tekebasi and 0 56 mm y in keldag yielding a 0 84 mm y average this rather fast uplift appears to be related to the vertical component of the strike slip active faults in the samandag antakya fault zone

the classic marine isotope substage 5e since its identi cation nearly fty years ago marine iso tope stage 5 mis 5 has been placed onto absolute time scaleson the basis of three independent approaches cesare emiliani who set up the isotope stages emiliani 1955 depended onuranium series dating of the sediments a method that today isregarded as not generally capable of yielding useful precisionor accuracy broecker and van donk 1970 pioneered the ap proach of correlating to radiometrically dated marine coral ter races thishasbeenmuchaidedinrecentyearsbyimprovementsin the precision and accuracy of these age determinations thathave owed from the development of thermal ionization massspectrometry tims for uranium series dating edwards

changes in the thermocline structure of the indonesian outflow during terminations i and ii we present centennial records of sea surface and upper thermocline temperatures in core md01 2378 from the timor sea which provide new insights into the variability of the indonesian outflow across the last two glacial terminations mg ca in globigerinoides ruber white s s indicates an overall increase of 3 2 degrees c in sea surface temperature sst over termination i following an early holocene plateau at 11 3 6 4 ka ssts cooled by 0 6 degrees c during the middle to late holocene 6 4 0 7 ka the early holocene warming occurred in phase with increasing northern hemisphere summer insolation coinciding with northward displacement of the intertropical convergence zone enhanced boreal summer monsoon and expansion of the indo pacific warm pool thermocline temperatures pulleniatina obliquiloculata mg ca gradually decreased from 24 5 to 21 5 degrees c since 10 3 ka reflecting intensification of a cool thermocline throughflow the vertical structure of the upper ocean in the timor sea evolved in similar fashion during the holocene and mis5e although the duration of sst plateaux differed 11 3 to 6 4 ka in termination i and from 129 to 119 ka in termination 11 which was probably due to the more intense northern hemisphere summer insolation during mis 5e during both terminations sst increased simultaneously in the southern high latitudes and the tropical eastern indian ocean suggesting virtually instantaneous atmospheric climate feedbacks between the high and low latitudes c 2008 elsevier b v all rights reserved

late cretaceous eocene nannofossil and magnetostratigraphic correlations near gubbio italy abstract using a modified sample preparation technique we have been able to establish a detailed lower campanian to upper eocene nannofossil stratigraphy in the bottaccione and contessa highway sections near gubbio appearance and extinction levels of virtually all the commonly used calcareous nannofossil zonal markers have been recognized and can now be closely correlated with the planktonic foraminifera zonation and the magnetic reversal stratigraphy previously established in these sections comparisons with the nannofossil calibrations of the oceanic magnetic anomaly sequence in deep sea drilling project dsdp sites suggest that magmetic subchrons c17n and c25n are missing in the bottaccione section the observed variability of the relative stratigraphic position of most plankton events is confirmed to less than one magnetic subchron absolute abundance paleobiogeographic restriction and differential preservation render some of the traditionally used biostratigraphic events less reliable than others

chronology of the last glacial cycle in the european alps chronological data for glacier advances in the european alps between the last interglacial eemian and the holocene are summarised 115 to 11 ka during this time glaciers were most extensive extending tens of kilometres out onto the forelands between 30 and 18 ka that is synchronous with the global ice volume maximum of marine isotope stage mis 2 evidence for ice expanding to just past the mountain front for an earlier major glacier advance comes from swiss sites where advances have been luminescence dated to mis 5d 100 ka and mis 4 70 ka up to now no such evidence has been found in the eastern alps by 18 ka more than 80 of the late wurmian ice volume had gone subsequently glaciers readvanced reaching into the upper reaches of the main valleys during the lateglacial gschnitz stadial which likely occurred around 17 ka with final moraine stabilisation no later than 15 4 ka the link of the egesen stadial with the younger dryas climate deterioration is supported by exposure ages from four sites as well as minimum limiting radiocarbon dates from bogs within former glacier tongue areas key questions on the spatial and temporal variability of ice extents throughout the last glacial cycle have yet to be answered copyright 2008 john wiley sons ltd

increasing vegetation and climate gradient in western europe over the last glacial inception 122 110 ka data model comparison high resolution terrestrial pollen and marine planktic and benthic isotopes coarse fraction and n pachyderma s analyses have been performed in the marine isotope stage mis 5 interval of images core md99 2331 retrieved in the northwestern iberian margin this study shows the occurrence of a zeifen interstadial stadial succession on land and in the ocean during the first part of mis 5e in northwestern iberia the eemian is marked from 126 to 122 ka by the development of deciduous quercus forest at the same time as mediterranean forest colonised southern iberia and deciduous quercus corylus forest occupied northernmost european regions from 121 to 115 ka carpinus betulus forest developed in nw iberia indicating a winter cooling by 2degreesc on land and an increase in annual precipitation by 100 200 min along with a sea surface temperature sst decreasing trend off iberia a similar cooling has been documented at the same time in northern germany 52degreesn by the replacement of deciduous forest by coniferous abies picea formations implying a southward displacement of the deciduous tree line between similar to60degreesn and 50degreesn as early as 120 ka the southward migration of the tree line between 72degreesn and 58degreesn simulated by the earth model of intermediate complexity mobidic from 122 and 120 ka and considered as a major process to initiate the last glaciation is therefore compatible with data between 115 and 110 ka the substantial ice accumulation in northern high latitudes mis 5e 5d transition was synchronous with successive drops c26 and c25 in northeastern atlantic sst in northwestern iberia abies pinus trees developed at the expense of quercus carpinus forest a tundra like environment occupied northern germany marking the end of the interglacial in northwestern europe at 115 ka and boreal forest likely colonised northeastern france the first displacement of the vegetation belts at 121 ka was enhanced at 115 ka indicating an amplification of the vegetation and climate gradients in northeastern atlantic and european borderlands probably related with the well developed ice caps at that time the comparison between the general trend in the estimated and simulated mobidic winter and summer temperatures for latitudes between 35 and 45degreesn shows that both follow quite straightforwardly the precession signal although the simulated and reconstructed temperatures agree better in the south than north of 40degreesn annual precipitation is exhibiting opposite trend in the data and in the model this contradiction is likely the fact that the zonal climate simulated by the model may not accurately represent the regional climate features as reconstructed from the pollen c 2004 elsevier b v all rights reserved

speleothem record of the last 180 ka in villars cave sw france investigation of a large δ18o shift between mis6 and mis5 the vil car 1 flowstone core from villars cave sw france provides one of the first european speleothem records extending back to 180 ka based on ueth tims and mc icp ms measurements the core offers a continuous record of termination ii and the last interglacial the penultimate deglaciation is characterized by a prominent 5 depletion in calcite d 18 o determining which specific environmental factors

accumulation of bank top sediment on the western slope of great bahama bank rapid progradation of a carbonate megabank high resolution seismic profiles and submersible observations along the leeward slope of western great bahama bank show large scale export of bank top sediment and rapid progradation of the slope during the holocene a wedge shaped sequence up to 90 m thick is present along most of the slope and consists of predominantly aragonite mud derived from the bank since flooding of the platform 6 8 ka total sediment volume of the slope sequence is 40 80 that of holocene sediment currently retained on the bank maximum rates of vertical accumulation and lateral progradation are 11 15 m ka and 80 110 m ka respectively 10 to 100 times greater than previously known for periplatform muds slope deposition of exported mud during sea level highs appears to have been a major mechanism for the westward progradation of great bahama bank throughout the quaternary this may provide a critical modern analogue for ancient progradational margins

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

the impact of tsunami wave force on elevated coastal structures abstract we examined a potential strategy for mitigating injury and death during tsunamis by conducting numerical simulations for a vertical evacuation structure with a breakaway ground floor the simulation produced the uplifting load on the bottom slab the frontal impact force and the overturning moment depending on the structure s size and bottom slab elevation and the wave s froude number with a proper normalization the force and moment coefficients were generalized to become not explicitly dependent on the height of the bottom slab the exposure of the bottom slab to wave impact has increased the probability of the structure to overturn based on our findings we propose a maximum moment coefficient of 0 84 to decide on the overturning stability of the structure

tracing time in the ocean a brief review of chronological constraints 60 8 kyr on north atlantic marine event based stratigraphies abstract well resolved event based stratigraphies in marine sediments spanning a significant portion of the last glacial period 60 8 kyr provide a unique opportunity for time stratigraphic correlation in the north atlantic region here we review the current methods available to chronologically constrain these event based stratigraphies highlighting in particular the value of tephrochronology as an independent tool to validate correlations between records while the intimate protocols lowe et al 2008 blockley et al 2011 are equally applicable to marine and terrestrial records spatially and temporally variable marine radiocarbon reservoir age effects mres provide a challenge to using marine radiocarbon in the former as an independent chronostratigraphic tool despite the inherent uncertainties associated with tuning we conclude that the mid points of the common abrupt warming transitions associated with the well defined millennial scale climate oscillations the dansgaard oeschger d o cycles observed in the oxygen isotopes of the greenland ice cores and north atlantic sea surface temperature sst records currently provide the most robust correlation tie points from which to derive age control in this invited intimate special issue article we propose a new protocol for establishing marine event based chronostratigraphies in the north atlantic region and focus on areas of chronological potential in palaeoceanographic research

experiments and computations of solitary wave forces on a coastal bridge deck part i flat plate abstract horizontal and vertical forces acting on a two dimensional horizontal plate due to solitary waves are investigated by conducting a series of laboratory experiments as well as cfd calculations a total of 133 cases were tested including four water depths four submergence depths and three elevations above the swl and five wave amplitudes following the experiments computational results obtained by the cfd package openfoam are presented for both vertical and horizontal forces the comparisons made with the calculations show that openfoam s interfoam solver that we specialized to euler s equations here can successfully simulate the data in many cases with the wave force data presented here it will now be possible to compare numerical predictions of various shallow water wave equations with the experiments the data will also be useful to estimate the tsunami loads on submerged structures such as breakwaters and elevated structures such as coastal bridge decks the case of the flat plate either submerged or elevated is considered in this paper part i while the case of a plate with girders will be discussed in a companion paper under the same title part ii

timing and progression of the last interglacial derived from a high alpine stalagmite 1 u th dating and oxygen isotope analysis of a stalagmite from spannagel cave in the austrian alps provides information about the timing and progression of the last interglacial climate we determined two distinct growth intervals warm climate from 130 7 thousand years ka before the present to 130 0 ka and from 125 7 ka to 118 2 ka the latter containing two periods of ceased stalagmite growth colder climate at around 123 8 ka and 120 5 ka high resolution 18o analysis of stalagmite spa 50 reveals a clear regular cyclic pattern with periods of 197 109 and 21 years which are likely to be related to the suess gleissberg and hale cycles respectively indicating that eemian climate in the alps was forced by the sun

the chronostratigraphic significance of seismic reflections along the bahamas transect abstract continuous cores drilled during the bahamas drilling project bdp and the ocean drilling program odp leg 166 along a transect from the top of great bahama bank to the basin in the straits of florida provide a unique data set to test the assumption in seismic stratigraphy that seismic reflections are time lines and thus have a chronostratigraphic significance seismic reflections that are identified as seismic sequence boundaries ssbs were dated by means of biostratigraphy in the five odp sites and by a combination of biostratigraphy magnetostratigraphy and sr isotope stratigraphy in the two bdp sites the seismic reflection horizons are carried across a variety of facies belts from shallow water carbonates over slope carbonates to drift deposits in the straits of florida within this system 17 ssbs were identified and dated despite the fact that the seismic reflections cross several facies belts their ages remain remarkably constant the average offset in all sites is 0 38 myr in no cases do the seismic reflections cut across time lines the age differences are the combined result of the biostratigraphic sampling frequency the spacing of marker species that required extrapolation of ages and the resolution of the seismic data in addition uncertainties of age determination in the proximal sites where age diagnostic fauna are rare add to the age differences between sites therefore it can be concluded that the seismic reflections which mark the ssbs along the bahamas transect are time lines and can be used as stratigraphic markers this finding implies that depositional surfaces are preferentially imaged by reflected seismic waves and that an impedance contrast exists across these surfaces facies successions across the sequence boundaries indicate that the sequence boundaries coincide with the change of deposition from times of high to low sea level in the carbonate setting of great bahama bank sea level changes produce changes in sediment composition sedimentation rate and diagenesis from the platform top to the basin the combination of these factors generates differences in sonic velocity and thus in impedance that cause the seismic reflection the impedance contrasts decrease from the proximal to the distal sites which is reflected in the seismic data by a decrease of the seismic amplitude in the basinal area

interglacial variability mis 5 and mis 7 and dinoflagellate cyst assemblages in the bay of biscay north atlantic the interglacial periods of the late quaternary are frequently investigated as they constitute potential analogues for our modem climate and may shed light on the key questions of natural climate variability and future developments the aim of this work is to reconstruct the paleoenvironmental history of marine isotope stages mis 5 and 7 in deep sea sediments of the northern bay of biscay north east atlantic ocean on the basis of a multiproxy compilation including analysis of dinoflagellate cyst assemblages we discuss the nature of the paleoenvironmental and paleoclimate changes that took place in this region recurrent successions of species marking the beginning and the termination of the interglacial complexes mis 5 and mis 7 revealed a coherent scheme of water mass migration during these key transitional periods moreover our data extend knowledge about the ecology of several dinoflagellate taxa in particular we discuss the ecology of spiniferites septentrionalis and note that this species can be used as a biostratigraphical tracer in north atlantic quaternary sediments until a major event of iceberg calving occurred during mis 6 dated to around 150 ka bp the dinocyst spinferites mirabilis appears to be an important proxy for recognizing warm intervals within interglacial complexes during mis 5e the last interglacial this species is represented by the highest percentages ever recorded in sediments from the north atlantic region peak occurrence of this species during mis 7 indicates that substage mis 7c the second warm interval of the penultimate interglacial represents the climatic optimum during the mis 7 interglacial complex

magnetostratigraphic dating of shallow water carbonates from san salvador bahamas magnetostratigraphic results are reported here from a sequence of late neogene quaternary shallow water carbonate sediments from a continuous core drilled on the island of san salvador bahamas on the basis of the remanent magnetism of 136 samples from a 91 m measured section of core the polarity sequence can be correlated with the magnetic polarity time scale from the gilbert chron early pliocene through the late brunhes chron late pleistocene holocene magnetic polarities were determined on the basis of relative up down direction in the unoriented core extraction studies of the magnetic particles reveal the presence of single domain crystals of magnetite resembling those produced by the magnetotactic bacteria and algae the sequence of reversals provides a minimum of six new major chronostratigraphic markers for the pliocene pleistocene of the bahamas it confirms and refines the local timing of both the lithologic change from skeletal to nonskeletal sediments and the disappearance of coral and molluscan species from the bahamas as upper late pliocene between 2 6 and 2 7 ma that the primary magnetic remanence is preserved in shallow water carbonates including replacement dolomites suggests that this technique could be used to date similar tertiary and possibly even older carbonate sequences the establishment of a reliable magnetostratigraphy provides refined dating of shallow water carbonates and regional faunal appearances or disappearances sediment accumulation rates subsidence and depositional events

insolation and glacial interglacial control on southwestern african hydroclimate over the past 140 000 years available online xxxx editor g m henderson keywords leaf wax n alkane hydrogen and carbon isotopes african palaeoclimate monsoonal precipitation namibia the past climate evolution of southwestern africa is poorly understood and interpretations of past hydrological changes are sometimes contradictory here we present a record of leaf wax d and 13 c taken from a marine sediment core at 23 s off the coast of namibia to reconstruct the hydrology and c 3 versus c 4 vegetation of southwestern africa over the last 140 000 years 140 ka we find lower leaf wax d and higher 13 c more c 4 grasses which we interpret to indicate wetter southern hemisphere sh summer conditions and increased seasonality during sh insolation maxima relative to minima and during the last glacial period relative to the holocene and the last interglacial period nonetheless the dominance of c 4 grasses throughout the record indicates that the wet season remained brief and that this region has remained semi arid our data suggest that past precipitation increases were derived from the tropics rather than from the winter westerlies comparison with a record from the congo basin indicates that hydroclimate in southwestern africa has evolved in antiphase with that of central africa over the last 140 ka

wave loads on rubble mound breakwater crown walls abstract crown walls are primarily built to reduce wave overtopping of mound breakwaters several methods have been proposed to calculate wave loads on the crown wall e g iribarren and nogales iribarren r nogales c 1964 obras maritimas dossat ed madrid 376 pp jensen jensen o j 1984 a monograph on rubble mound breakwaters danish hydraulic institute and gunbak and gokce gunbak a r gokce t 1984 wave screen stability of rubble mound breakwaters international symposium of maritime structures in the mediterranean sea athens greece pp 2 99 2 112 in this paper a new method based on those previous results and on further experimental work using monochromatic waves is presented the application of the new method requires waves breaking on the armour layer i e only broken waves will reach the crown wall the method is extended to irregular waves via the hypothesis of equivalence introduced by saville saville t 1962 an approximation of the wave run up frequency distribution proc 8th international conference on coastal engineering mexico city and is applied to the crown walls of gijon and bilbao breakwaters in spain the comparison of the probability force distributions obtained by the present method to that measured by burcharth et al burcharth h f frigaard p berenguer j m gonzalez b uzcanga j villanueva j 1995 design of the ciervana breakwater bilbao in t telford ed proc 4th coastal structures and breakwaters chap 3 institution of civil engineers and jensen 1984 is relatively good

sea level events in the south pacific linked with the messinian salinity crisis cores drilled through the carbonate cap of niue a mid oceanic carbonate platform in the south pacific contain an unusually well resolved stratigraphic section of the latest miocene at 35 to 140 m depth below sea level intensely leached and chalky intervals associated with pronounced 18 o and 13 c depletions mark the position of dissolution unconformities representing eight episodes of eustatic falls that outstripped the local rate of subsidence we demonstrate on the basis of sr isotope chronostratigraphy that these eustatic changes are correlative with the messinian salinity crisis events in the mediterranean sea level changes of about 10 m amplitude commenced at 6 14 ma and culminated in a large sea level fall that reached at least 30 m at 5 26 ma corresponding to the miocene pliocene boundary evaluation of the sea level history reported here and the contemporaneous mediterranean events supports the model of coupling between tectonic and eustatic factors that caused the onset and demise of the salinity crisis the available evidence suggests that during messinian time glacio eustatic falls and rises are likely to have modulated the connection between the atlantic and the mediterranean and influenced the evaporite deposition and may have contributed significantly to the final phase of isolation and desiccation of the mediterranean and its subsequent refilling during the zan clean deluge

tsunami generation in a large scale experimental facility abstract experimental studies on tsunami are carried out since many years most of them by generating solitary waves with a piston type wave maker however today it is more and more appreciated that these kinds of waves actually do not represent a real tsunami very well as particularly for the shallow waters at the coast the wave length becomes comparably far too short recently new generation methods for scaled down real tsunami experiments were suggested as it was doubted that sufficiently long waves could be generated with a classical wave maker the present paper shall disprove these arguments by providing results of a study carried out in the large wave flume groser wellenkanal gwk where waves of periods between 30 s and more than 100 s at 1 m water depth were successfully generated with a piston type wave maker results for elongated solitary waves trough led n waves and real tsunami records as a combination of a different number of general solitons sech2 waves are presented finally the requirements and limitations to bring a real tsunami into the laboratory are discussed

north atlantic current and european environments during the declining stage of the last interglacial this paper provides a tentative reconstruction of environmental shifts in europe associated with changes of the north atlantic current and related meridional sea surface temperature sst gradients during most of the eemian interglacial ca 126 115 ka the north atlantic current extended far north into the nordic seas and european environments were comparable to those of the holocene however ca 115 ka an sst drop in the nordic seas marked a southward displacement of the north atlantic current this hydrographic shift was associated with substantial cooling in northern europe and drier conditions in the mediterranean region the polar timberline retreated southward from 69 n in northernmost scandinavia to 52 n in central europe and thermophilous deciduous trees became extinct north of the 48th parallel woodlands persisted in southern europe for another 5 k y well into marine isotope substage 5d these conditions indicate steep vegetation and climate gradients at the inception of the last glacial

sr isotopic variation in shallow water carbonate sequences stratigraphic chronostratigraphic and eustatic implications of the record at enewetak atoll sr isotope data from two boreholes within the lagoon at enewetak atoll have been used to evaluate the use of such data to correlate date and monitor sea level change in shallow water carbonate sequences correlative stratigraphic intervals of relatively invariant 87sr separated by abrupt transitions to lower 87sr with increasing depth are recognized in both boreholes conversion of 87sr values to age via calibration with the seawater 87sr trend with age indicates that correlative and synchronous deposition of atoll sediments occurred at 0 4 1 2 and 2 1 ma in contrast a 5 m y hiatus is recognized in one borehole but not the other sr isotope stratigraphy sis is a powerful stratigraphic and chronostratigraphic tool in shallow water carbonate sequences only when significant secular variation of 87sr occurs and retention of depositional 87sr values is demonstrated the latter is best demonstrated when 87sr data are integrated with 18o 13c sr content data and petrographic observations several diagenetically altered intervals have greater 87sr values low 13c values and low sr ca ratios relative to adjacent intervals a combination that is consistent with open system meteoric diagenesis calcite cements from these intervals have early pleistocene 1 2 ma 87sr values despite their occurrence well within the late pliocene 2 1 ma sequence thus local sedimentological and diagenetic processes have produced intralagoon variability in the sis of the two boreholes complicating subsurface stratigraphic correlations the occurrence of anomalously young calcite cement relative to adjacent limestone is a direct response of the interaction of sea level change and meteoric phreatic diagenesis whereby overlying metastable carbonates with greater 87sr values are dissolved during periods of atoll emergence and sea level lowstand liberating sr and soil gas co2 to the pore fluid which is then incorporated into downflow meteoric phreatic diagenetic calcite the stratigraphic relation between the sites of carbonate dissolution and diagenetic calcite precipitation suggest an early pleistocene 1 2 ma sea level fall of between 34 and 64 m moreover the stratigraphic position and inferred age of paleophreatic lens calcite when backtracked for subsidence suggest that early pleistocene 1 2 ma sea level was 72 81 m range of 60 100 m below present sea level the enewetak record of early pleistocene sea level lowstand elevation agrees reasonably well with proxy sea level records inferred from sequence stratigraphy and deep sea foraminiferal 18o data however the enewetak record of the amplitude of early pleistocene sea level change is more consistent with the deep sea foraminiferal 18o proxy than the sequence stratigraphy proxy

imprints of high salinity water plumes originating from the red sea during termination ii abstract the investigation of a core collected in the socotran area western indian ocean provides new insights into water mass exchanges between the red sea and the gulf of aden through the strait of bab el mandeb during the penultimate deglaciation the benthic oxygen isotope record documents the occurrence of stillstands and possibly reversals within the general trend of sea level rise plumes of warm and salty waters are recorded at the surface of the arabian sea and as far as the socotran coast for each increase in sea level these plumes disappeared whenever global sea level stopped rising or showed a brief lowering according to their high salinities these plumes can only originate in the red sea the sill of bab el mandeb becoming deeper and wider during the deglaciation allowed greater exchange between both seas and stronger flow out of the red sea at each episode of sea level rise isotopic and faunal evidence suggest a strengthening of coastal upwelling in the arabian sea during these periods this increase in upwelling activity may explain how plumes of highly saline waters were maintained at the surface moreover the high salinity surface plumes may have facilitated upwelling activity through the destabilisation of density stratification in the upper water column the occurrence of at least high salinity salty water outflows during termination ii confirms the step wise non linear structure of the penultimate deglaciation providing a perfect example of the threshold concept in rapid climate changes

astronomically forced variations in western african rainfall 21 n 20 s during the last interglacial period this study documents the long term evolution of western african precipitation during the last interglacial lig we compare geochemical records obtained on nine sediment cores from the western african margin to a transient simulation 130 115 ka performed with an ocean atmosphere general circulation model and insolation as sole forcing good agreement between proxy records and model outputs indicates that long term changes in western african precipitation largely responded to insolation variations during most of the lig after an early lig dry phase related to high latitude iceberg melting or dating uncertainties boreal summer insolation controlled the intensification of the north african monsoon between 127 and 122 ka perhaps facilitating human migrations out of africa equatorial african rainfall slightly increased throughout the lig in response to increasing annual insolation east west contrasting rainfall evolutions at 10 20 s illustrate the complex southern african response in contrast to more direct responses of north and equatorial western africa to insolation forcing

radiometric isotopic and petrographic evidence of changing interglacials over the past 550 000 years from six stalagmites from the serra do courel in the cordillera cantabrica of northwestern spain abstract seventy u th ages from six stalagmites from the cordillera cantabrica in northwestern spain indicate deposition during interglacial but not glacial stages over the last 550 kyr stable isotope data and petrographic observations suggest that within each interglacial conditions typically progressed from drier to wetter consideration of the most precise u th ages suggests that stalagmite deposition occurred in times more predictable from european pollen records than from the global marine isotope record for example during the last interglacial ages suggest deposition in an interval better characterized as the eemian as opposed to mis 5e and during the st germain i or mis 5c interval the same holds for mis 7 where ages suggest deposition during mis 7a and mis 7c but not mis 7e these age ranges for interglacials consistently later than those suggested by the benthic marine record are compatible with warm conditions maintained by thermohaline circulation that simultaneously supplied the moisture for growing ice sheets of the subsequent glaciation trends both within and across these six stalagmites suggest that cooler temperatures were associated with wetter conditions both during interglacials and in conditions intermediate between interglacials and glacials in northern spain in contrast other researchers results from a stalagmite from the last glacial maximum and subsequent deglaciation suggest colder temperatures were associated with drier conditions the two trends combine to suggest wettest conditions in times intermediate between interglacials and glacials compatible with a model in which modern climatic belts from dry arctic to wet european to dry marginal saharan have moved over northern spain in the cycle from glacial to interglacial times extrapolation to a warmer future would suggest drier conditions in the northern iberian peninsula than those of today

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr