new evidence for two highstands of the sea during the last interglacial oxygen isotope substage 5e sedimentologic stratigraphic and geochronologic analyses of a previously undescribed carbonate section on oahu hawaii provide new evidence for two distinct sea level highstands on oahu during the last interglacial period oxygen isotope substage 5e whereas electron spin resonance and uranium series ages 122 8 ka to 152 25 ka and 115 10 ka to 160 15 ka respectively of in situ corals place the age of the deposits within substage 5e it is the unique sequence of strata found in these exposures that reveals the two transgressions a highstand lagoonal deposit of coral algal bafflestone is overlain by large seaward dipping slabs of beach rock the beachrock deposited during a mid 5e regression is in turn overlain by a second highstand lagoonal deposit this sequence was deposited in a broad shallow back reef embayment that was very sensitive to fluctuations in sea level elsewhere along much of the shoreline of oahu an in situ coral algal framestone waimanalo formation representing the initial 5e highstand is erosionally truncated on its upper surface this erosional unconformity represents the mid 5e lowstand and separates the framestone from overlying seaward dipping planar bedded grainstone and rudstone leahi formation that accumulated during the second 5e highstand

the port morant formation upper pleistocene jamaica high resolution sedimentology and paleoenvironmental analysis of a mixed carbonate clastic lagoonal succession abstract the port morant formation consists of a mixed clastic carbonate sedimentary sequence that was deposited as a lagoon fill during the sangamonian interglacial ten sedimentary facies are recognised and sequence stratigraphic analysis indicates the presence of transgressive and highstand systems tracts the transgressive systems tract consists of a basal transgressive conglomerate facies i crustose coralline algal bindstones boundstones ii and 2 m high solenastrea coral heads iii the highstand systems tract is represented by sediments of a braid delta fan delta prograding into the lagoon iv and v marine pebbly sandstones deposited adjacent to mangrove swamps vii more distal algal mudstones viii and sheet like vi and channelized ix conglomerates filling delta top distributary channels a barrier and or fringing reef is present x but its relationship with the lagoon fill sediments is obscure due to poor exposure carbonates are restricted to the transgressive systems tract and the barrier fringing reef transgressive and or highstand systems tract two transgressive events are recognized the transgressive systems tract facies i to iii and facies vii the latter either a second sea level rise or due to delta abandonment a single coral date from facies vii gave an age of 132 7 kyr this indicates that the upper transgressive event facies vii belongs to the early highstand that has been recognized in isotope substage 5e the lower transgressive event facies i to iii in the port morant formation is therefore either also of this age or older

sea level change and superstorms geologic evidence from the last interglacial mis 5e in the bahamas and bermuda offers ominous prospects for a warming earth abstract geological observations from last interglacial lig mis 5e eemian carbonate landscapes in the bahamas and bermuda reveal a turbulent climate transition at the close of the peak interglacial the interval is associated with rapid multi meter shifts in sea level as major ice sheets melted and or collapsed sedimentary evidence from the eastern bahamas includes wave transported megaboulders lowland chevron storm ridges and hillside runup deposits this trilogy collectively provides direct geological evidence of frequent intense storms generating sustained long period waves from the northeast atlantic ocean penecontemporaneous with wave deposits is the subtidal production and flux of a massive volume of ooid sediments associated with amplified winds and storminess during the latter half of mis 5e that resulted in exponential island growth steeper temperature and pressure gradients were evident in the north atlantic ocean while the southern ocean appears to have had a major role in affecting atmospheric co2 as warming of the southern ocean drives ventilation of the deep ocean co2 in turn acts as a tight control knob on global climate the dramatic oceanographic and island building events of late mis 5e are unique among other interglacial periods of the past half million years the lig record reveals that strong climate forcing is not required to yield major impacts on the ocean and ice caps antarctic ice cores document that lig atmospheric co2 was 275 ppm while global temperature was in terms of lyellian uniformitarian principles the trilogy of coeval deposits of mis 5e described herein do not translate to our modern climate parameters and further cannot be explained by coincidental megatsunami in our industrial world rapidly increasing atmospheric co2 rates 2 ppm yr have surpassed 408 ppm levels not achieved since the pliocene 3 ma ago while global temperature increased 1 c since the 1870s with greatly increased co2 forcing at unmatched rates except perhaps during global extinction events dramatic change is certain in the interest of our future world we must seek to understand the complex set of linked natural events and field observations that are revealed in the geology of past warmer climates

evidence for sea level oscillations by the characteristic thickness of marine deposits from raised terraces of southern calabria italy abstract clastic deposits associated with marine terraces can provide evidence for detecting eustatic oscillations the method is based on the characteristic thickness ct of beach formations which are generally deposited on a wave cut platform between the breakpoint and the swash upper limit on any present day coast ct reflects equilibrium related to current shore processes with a constant sea level it represents a local threshold t cr as when sea level rises ct increases by a value equal to the rise amplitude this amount is reduced in uplifted areas by the magnitude of coeval uplifting the amplitude of sea level variations detected by ct can be calculated knowing ct t cr uplift rate and the duration of an oscillation the method is applied to the clastic deposits of 23 marine terraces stepped between 52 and 172 m and shaped over the mis 5 mis 4 period along the calabria coast of the messina strait not only the great orbital oscillations mis 5 5 mis 5 3 mis 5 1 and mis 3 are recorded but also several rapid and low amplitude events are detected into each substage the most surprising result is the ten small oscillations during mis 5 5 the duration of which ranges between 2 ka and less than 1 ka while sea level oscillates from 0 5 to 12 m in amplitude by calculating initial relative sea level highstands and also lowstands preceding them detailed eustatic oscillations of the curve are drawn

influence of geology in the geochemistry signature of itacolomi state park waters minas gerais brazil in all geological scenarios mineral water reactions will affect the water chemistry as such water resources in different rocks commonly involve different hydrogeological compartments the aim of this work is to evaluate the influence of geology in the geochemistry signature of itacolomi state park waters to do so a survey of the geological units in the area was carried out a geological stratigraphic division was made and its correlation with the main geological events was determined using the advantages of gis all the catchments were delimited based on this division near 30 stream and lake segments were chosen for analyses in each point all physiochemical properties of the water were measured and samples were collected to determine the concentrations of major and trace elements by icp oes the dynamics of the itacolomi state park rock soil and stream water solutions suggest that mixing of drainage waters from different bedrock and soil sources regulates stream water physical chemical parameters and solute concentrations the analytical data showed a clear correlation between the chemical compositions of the solute and the geological characteristics of the catchment units that are covered by iron oxide hardpan manso unit and iron banded formations custodio unit show a large amount of soluble elements including high values of fe and mn on the other hand the presence of high values of al and k itacolomi unit are a direct consequence of the presence of quartzite associated with low ph values

spore diversity trends in the middle devonian of the chaco salteno plain northwestern argentina abstract devonian deposits in northwestern argentina were historically studied with stratigraphical purposes since these layers conform the source rocks of the producing basins of the region a fairly well preserved palynomorph assemblage from the tonono formation provides an opportunity to perform the first quantitative analysis to study the evolution of diversity in the succession two associations are here defined by both stratigraphic distribution of species and cluster analysis ranging from the lower eifelian to the lower givetian rarefaction analysis reveals the existence of a relatively rich miospore population species richness increases while there is a drop in diversity and evenness towards the top of the column the increment of the marine components towards the latter section indicates shifts in the shoreline the influx of warmer water into higher latitudes as highlighted by the arrival of the brachiopod tropidoleptus could have favored the inception of new spore species in the settled community these results add to evidence that some groups build up the number of species in disturbed settings and evenness is reduced with each new species introduced

a depositional model for organic rich duvernay formation mudstones abstract the upper devonian duvernay formation of western canada is an organic rich shale formation now targeted as a hydrocarbon reservoir we present a detailed sedimentological analysis of the duvernay formation in order to better understand organic rich mudstone depositional processes and conditions and to characterize the vertical and lateral heterogeneity of mudstone lithofacies that affect petrophysical and geomechanical rock properties organic rich mudstone facies of the duvernay formation were deposited in a dynamic depositional environment by a variety of sediment transport mechanisms including suspension settling turbidity currents and bottom water currents in variably oxygenated bottom waters suspension settling dominated in distal relatively deep areas of the basin but evidence for weak turbidity currents and bottom water currents was observed in the form of graded beds and thin grain supported siltstone laminae organic enrichment primarily occurred in distal areas as a result of bottom water anoxia and low depositional rates of inorganic sediment in deep water locations near platform margins alternating silty sandy contourite beds and organic rich mudstone beds are present the former interpreted to have been deposited and reworked by bottom water currents flowing parallel to slope in shallower more oxygenated settings mudstone lithologies vary from calcareous to argillaceous these sediments were deposited from suspension settling turbidity currents and bottom water currents although primary sedimentary structures are often obscured by extensive bioturbation locally organic enrichment in dysoxic rather than anoxic bottom waters was driven by a slightly increased sedimentation rate and possibly also by aggregation of sedimentary particles in the water column due to interaction between organic matter and clay minerals large variations observed in sediment composition from siliceous to calcareous to argillaceous reflect multiple biogenic carbonate and clastic sediment sources sediment composition is influenced by basin morphology circulation patterns sea level variation and proximity to sediment sources

multi stage reef development on barbados during the last interglaciation by mapping the vertical and lateral distribution of reefal facies on the west and south coast of barbados we have produced a revised model of reef development for the last interglaciation we find that reef architecture around barbados has significant complexity including evidence for wave exposure related variations in reef geometry and at least 3 stages of reef development that were controlled by variations in sea level during the main stage of development an acropora palmata dominated reef crest aggraded 22 m in response to a minimum sea level rise of 20 m during stage 2 a sea cave was cut 3 4 m above the fossil reef crest possibly indicating that reef growth was terminated before sea level reached the highstand similar sequences elsewhere in the caribbean indicate that this early reef demise may not be a local phenomenon several reefs apparently stopped growing between 2 and 4 m and only in sheltered areas did they reach the highstand at 6 m as recorded by intertidal notches this pattern of reef demise has previously been related to rapid sea level rise at the end of the interglacial but stratigraphic data are equivocal the final stage of reef development on barbados occurred when sea level began to fall this fall was rapid leaving a thin but widespread veneer of reef crest deposits over the proximal reef front and discontinuous intertidal and shallow subtidal deposits capping the distal reef front although further dating is required to differentiate these three stages our only reliable u th tims date indicates that almost 50 of the exposed reef had accreted by 129 ka giving an estimate of 15 ka for the main aggradational stage furthermore reports of relict reef crests buried beneath these exposed deposits indicate that our revised model is incomplete and that earlier stages of reef growth occurred during the last interglaciation these earlier stages imply that sea level was at an interglacial level for as long as 20 ka supporting the devils hole record of interglacial duration unfortunately these estimates could not be verified directly because most of our u th data show major stratigraphic age reversals attributed to diagenesis this pattern is also evident in all other well dated reefal units in the caribbean and leads us to conclude that only diagenetically screened precise stratigraphically consistent coral dates can be used to directly estimate the duration of the last interglaciation

devonian sea level change in bolivia a high palaeolatitude biostratigraphical calibration of the global sea level curve article i nfo available online xxxx during the devonian period the cool water malvinokaffric realm was located at high palaeolatitudes in the southern hemisphere the realm is defined by its highly endemic marine benthic fauna which makes extra malvinokaffric correlations problematic investigation of the devonian palynomorphs from an extensive regional sub surface dataset 24 wells in the chaco basin bolivia reveals the presence of a number of stratigraphically restricted and regionally correlative epiboles peak abundances of the distinctive palynomorphs bimerga bensonii crucidia camirense evittia sommeri petrovina connata and ramochitina magnifica these palynomorph epiboles were then located at outcrop by a high resolution palynological investigation 225 samples of two bolivian outcrop localities in the chaco basin bermejo santa cruz department and campo redondo chiquisaca department the important evittia sommeri epibole in the basal los monos formation is related to a marine transgression that is present in both these outcrop sections additional chronostratigraphic control on this marine transgression comes from the occurrence of rare goniatites in the base of the huamampampa formation at campo redondo which are at least early eifelian in age post chot c event based on the goniatite together with spore data the marine transgression with evittia sommeri in the basal los monos formation can be tentatively assigned to the mid devonian mid late eifelian kacak event the presence of a datable malvinokaffric goniatite has shown that key spore taxa which are used zonally in both laurussia and gondwana do not all have coincident first occurrences in both areas furthermore despite the appearance of some cosmopolitan elements in the microflora mid and late devonian spore assemblages in bolivia are distinct from other regions in being relatively impoverished in both progymnosperm and lycopod spores this floral difference is attributable to the malvinokaffric realm continuing to retain a distinctive cool climatic signature throughout this interval however the sporadic occurrences of extra malvinokaffric macrofauna in restricted stratigraphic intervals of the middle devonian in south america and south africa are significant the oldest known occurrence of the extra malvinokaffric brachiopod tropidoleptus in bolivia is coincident with the late eifelian basal los monos formation transgression hence there was a relationship between influxes of this fauna and marine transgressions i e temporary periods of reduced climatic gradient the migration of devonian spores and particularly heterosporous spores between gondwana and laurussia clearly occurs during the mid and late devonian this is at variance with models claiming a wide rheic ocean during much of the devonian

recognising the taghanic crisis in the devonian terrestrial environment and its implications for understanding land sea interactions the late mid devonian eday marl formation from the orcadian basin scotland is a terrestrial equivalent of the marine devonian taghanic crisis the eday marl from orkney contains a high resolution archive of climatic change controlled by the relative strength of the seasonal insolation this includes several distinct and discrete episodes of basin flooding as demonstrated by the deposition of lacustrine laminites bedded evaporites marginal sheet flood sands and marine influenced bioturbated sheet sands these flooding events are intercalated with intense and sustained episodes of aridity indicating that insolation was relatively weak and the monsoon climate was ineffective at drawing in seasonal rainfall recognition of these basin flooding events has enabled the definition of three new units the wha taing roeberry and berstane members the eday marl formation can be correlated offshore and also recognised within marginal facies as an aeolian intercalation an environmental hydrological and climatic interpretation is given for the different events recognised in the eday marl this sequence of events when combined with the palynological age dates enables a detailed correlation to be made with the marine tully formation of new york state this suggests that regressions forced by climatic aridity are significant for understanding the deposition of the shallow water carbonates of the tully formation in what is otherwise a clastic depositional system comparison with the pelagic marine record shows that the latter as yet gives only limited resolution of the taghanic crisis recognising the taghanic as a rapid alternation of cool arid and relatively hotter pluvial events provides a unifying explanation for the associated collapse in the terrestrial vegetation and the parallel faunal changes in the marine realm

quaternary stratigraphy of bermuda a high resolution pre sangamonian rock record abstract carbonate islands such as bermuda are created by climatic change warm climates and high sea levels stimulate carbonate sediment production that may ultimately result in island growth while cold glacials expose the platforms to weathering dissolution and soil formation of great importance in quaternary studies is the ability to decipher this climatic history mapping and geochronologic studies have established that bermuda may have one of the most continuous and detailed quaternary interglacial depositional records on a carbonate platform advances in racemization dating aar have offered a means of deciphering this climatic history and generating a high resolution stratigraphic and age framework for the quaternary bermudian interglacial units consist predominantly of eolianites with less voluminous occurrences of beach deposits and calcarenite protosols entisols glacial or stadial age terra rossa aluminous laterite paleosols whose degree of development is a function of time of exposure form boundaries between interglacial units d alloiso leucine l isoleucine a i ratios have been determined on marine pelecypods land snails and whole rock samples from mapped sections aminozones have been defined for two sangamonian and at least five pre sangamonian depositional intervals from kinetic models based on calibration with previously published u series coral dates estimated ages of middle pleistocene and older aminozones are f 190 000 265 000 years g 300 000 400 000 years h 400 000 500 000 years j 700 000 years and k 900 000 years aminozone g which is correlated with the upper town hill formation and isotope stage 9 is volumetrically the most important depositional event of the middle pleistocene the great mass of sediment deposited during this period suggests an interglacial of significant duration and prolonged shelf submergence during which the island grew to over half its present size only the sangamonian sensu lato rivals stage 9 in volume of eolianite deposited on the island sea level amplitude as determined from dated outcrops appears to correlate well with amplitudinal variations in the oxygen isotope record

devonian climate sea level and evolutionary events an introduction the face of planet earth has changed significantly through geological time dynamic processes active today such as plate tectonics and climate change have shaped the earth s surface and impacted biodiversity patterns from the beginning organisms on the other hand have the capacity to significantly alter earth s hydrological and geochemical cycles its atmosphere and climate sediments and even hard rocks deep down under the surface abiotic biotic interactions characterize earth s system history and together with biotic competition and food webs were the main trigger of evolutionary change innovations and biodiversity fluctuations within the palaeozoic the devonian was an especially interesting time interval as it was characterized by the mid paleozoic predator revolution signor brett 1984 brett 2003 and the related nekton revolution klug et al 2010 characterized by the blooms of free swimming cephalopods including the oldest ammonoids and fish groups e g toothed sharks and giant placoderms the rise of more advanced vertebrates including the oldest tetrapods e g blieck et al 2007 2010 niedzwiedzki et al 2010 the most extensive reef complexes of the phanerozoic e g kiessling 2008 and the greening of land by the diversification and spread of land plants including the oldest forests e g stein et al 2012 giesen berry 2013 which resulted in new soil types and changing weathering these major evolutionary trends did not unfold in a long interval of environmental stability but in times of numerous and repeated geologically brief global events that punctuated prolonged periods up to several million years in duration of relative stability termed ecological evolutionary subunits ee subunits boucot 1990 brett baird 1995 brett et al 2009 the bounding events even those of lesser intensity produced major re structuring in local to global ecosystems and are seen as critical drivers of long term evolutionary patterns brett 2012 these linked abiotic and biotic events and extinctions of different magnitude have been summarized by house 1983 1985 2002 walliser 1984 1996 and more recently by becker et al 2012 the devonian event succession is summarized in figure 1 two first order mass extinctions at the frasnian famennian boundary kellwasser crisis and at the end of the devonian hangenberg crisis characterized by the loss of major fossil groups classes and orders and complete ecosystems e g metazoan reefs early forests have to be viewed in the context of a complex global event sequence there are important similarities between discrete pulses phases of the major biotic crises and individual smaller scale events in our understanding second order global events are characterized by sudden extinctions in many groups and ecosystems including the complete disappearance of several widespread and diverse organism groups orders and families examples are the basal emsian atopus event where the planktonic graptolites finally died out the taghanic crisis frasnes events and lower kellwasser event third order global events show globally elevated extinction rates often at lower taxonomic level genera and species but within many clades and in several ecosystems examples are the silurian devonian boundary klonk event and the daleje chot c kacak condroz and annulata events fourth order global extinctions refer to the sudden disappearance of relatively fewer but widespread groups which implies a global not regional trigger this category may include the lochkovian pragian boundary

tyrrhenian coastal deposits from sardinia italy a petrographic record of high sea levels and shifting climate belts during the last interglacial isotopic substage 5e abstract detailed petrographic and sedimentological analysis of tyrrhenian coastal deposits from four sites in sardinia provides new data about climate and sea level changes during the early part of the last interglacial isotopic substage 5e and shows that facies analysis is not only useful for the identification of ancient depositional environments but also represents a powerful tool for evaluating past climatic conditions and sea level forcing mechanisms two shallowing upward sequences sensu ward w c brady m j 1979 strandline sedimentation of carbonate grainstones upper pleistocene yucatan peninsula mexico am assoc pet geol bull 63 362 369 commonly separated by an erosion surface and displaying complex geometric relationships occur above modern sea level at several locations along the shorelines of sardinia these sequences include upper shoreface to backshore deposits and were formed during separate sea level highstands attributed to isotopic substage 5e our recent revision of these deposits indicates that each sequence presents distinctive petrographic characteristics the older succession essentially contains mixed calcarenites rich in quartz grains and lithic fragments whereas the younger sediments are dominated by carbonate bioclasts such as red algae coral and mollusk fragments both units apparently accumulated in a similar depositional setting but during different climatic regimes the petrography of the lower unit reflects a temperate humid period characterized by increased weathering and continental erosion whereas the composition of the upper one suggests a dryer and possibly warmer climate favoring active carbonate production the disparity in petrographic composition between sequences probably records the migration of atmospheric circulation cells i e a shift of climate belts before and after the 128 ka insolation maximum our climatic data are coherent with the calculated insolation curves for isotopic substage 5e and thus support the milankovitch hypothesis for the origin of pleistocene climates in contrast our sedimentological data clearly show the occurrence of two distinctive highstands of sea level during this time period which does not agree with the hypothesis it follows that the relation between orbitally induced insolation variations climate and sea level is not necessarily straightforward

pleistocene collapse of the west antarctic ice sheet some glacial sediment samples recovered from beneath the west antarctic ice sheet at ice stream b contain quaternary diatoms and up to 108 atoms of beryllium 10 per gram other samples contain no quaternary diatoms and only background levels of beryllium 10 less than 10 6 atoms per gram the occurrence of young diatoms and high concentrations of beryllium 10 beneath grounded ice indicates that the ross embayment was an open marine environment after a late pleistocene collapse of the marine ice sheet

palynological calibration of devonian events at near polar palaeolatitudes in the falkland islands south atlantic in the devonian the falkland islands were part of the high latitude cape basin west falkland palynological assemblages are at a low thermal maturity level but also very low in diversity and dominated by simple spores with rare chitinozoans and acritarchs the south harbour member contains rare verrucate and sculptured trilete spores and is early lochkovian the fish creek member palynofloras are late lochkovian the best correlative datum is the transgressive fox bay formation where the palynological assemblage includes ramochitina magnifica and is equivalent to the sequence b transgression in brazil dated as late pragian earliest emsian the early eifelian upper fox bay formation spore assemblage is comparable to the sequence c transgression in brazil and the chote event the facies and position of the base port philomel formation prasinophyte rich black shale suggests the late eifelian transgression ka ak event above this level is the inception of geminospora lemurata base givetian the upper port stanley formation contains a late but not latest famennian assemblage comparisons with both south africa and south america indicate a number of correlative transgressive and regressive events that match to euramerica these correlations are at a continental scale and confirm eustatic control of these devonian events

evolution of marine terraces and sea level in the last interglacial cave hill barbados the uplifted marine terrace of last interglacial stage 5e age at cave hill barbados has been investigated with views toward terrace architecture developmental processes and sea level history methods include stratigraphic analysis of new deep exposures precise 230th geochronology and geomorphic mapping cave hill was central to earlier studies that led to important ideas on reef and terrace evolution but with which we find significant disagreement we present a new model of terrace evolution that emphasizes the role of marine erosion deposition of carbonate cover during the full eustatic cycle rather than only at highstand and principal reef development during transgression rather than at highstand by keep up rather than catch up growth the new model and geochronology contribute to an improved understanding of surficial processes during emergence of uplifting coral coasts and of global sea level changes in the last interglacial transgression in stage 5e at cave hill was accompanied by progressive marine erosion of a terrace floor and receding seacliff and deposition of a seaward thickening reefal wedge on the floor and above limestones of stage 6 and 7 ages the wedge contains a diachronous basal acropora palmata fringe reef this is overlain by an in place a cervicornis reef that aggraded progressively during sea level rise the transgressive phase took place between 136 ka or earlier and ca 128 ka during highstand between ca 127 and 120 ka the floor and seacliff continued to recede landward re gression began at or after ca 120 ka and sea level fell 37 m below the highstand level by ca 115 ka in stage 5c the seaward front of the last interglacial terrace was eroded landward an uncertain distance the sea level record at cave hill has implications for timing and constituent events of the penultimate glacial the last interglacial highstand and the fall in sea level at the transition from stage 5e to stage 5d shoreline angles which are isochronous linear geomorphic features are the most accurate markers of sustained highstand levels highstand levels and uplift rates interpreted from a palmata in barbados are less accurate and lower because the coral grew mainly in transgression the coral derived data therefore include uncertainties of depths of growth and collapse

uniformitarianism as a guide to rocky shore ecosystems in the geological record literature on pleistocene and neogene rocky shores is reviewed from a uniformitarian perspective to assess the fidelity of physical and biological information entrained in the geological record through present day processes coverage by latitude spans tropical to subarctic shores variations in paleotopography are illustrated by unconformities between sedimentary accumulations and rocks of igneous or non igneous origin former rocky shores occur across a range of geographic scales that include i spot localities ii embayments with continuous transition from exposed outer to protected inner shores and iii entire islands with windward and leeward shores differences in rate and mag nitude of sea level change affect rocky shore physiography terrace deposits characterize the pleistocene but ramp de posits typify older neogene shores on average species with hard parts account for about 50 of the modern rocky intertidal fauna on a regional basis regardless of latitude biodiversity is highest in mid latitudes fixed organisms with encrusting wedging or boring habits corals barnacles oysters other bivalves and vermetid gastropods show high potential for fossilization in growth position mobile organisms that cling to rocks gastropods crabs and echinoids suffer post mortem transport but may be immured within neptunian dikes or interstices among cobbles and boulders at best localized fossil deposits from the pleistocene reflect 30 of the biodiversity of skeletonized organisms tabulated from modern rocky shores on a regional basis uniformitarianism provides little insight into the diversity of soft bodied organisms excluding stromatolites that joined the ecosystem in precambrian times and the extent to which soft bodied organisms dominated shore life through later times

coral reef response to quaternary sea level and environmental changes state of the science there is considerable uncertainty about future sea level projections due to the current poor understanding of the vulnerability and sensitivity of ice sheets to global warming fossil coral reefs represent a unique archive of sea level and associated environmental changes that extend far beyond instrumental records here recent advances in this field are summarized focusing on periods of earth history typified by rapid sea level rise and short term climate excursions sea level and reef response records from the last deglaciation and periods characterized by higher sea level stands and short term and low magnitude sea level oscillations such as the mid to late holocene and the last interglacial are synthesised special emphasis is given to understanding how coral reefs have responded to these changes in terms of reef development architecture and composition finally seven major challenges and future research directions are identified

u series evidence for two high last interglacial sea levels in southeastern tunisia abstract pleistocene raised marine deposits in southeastern tunisia consist of a siliciclastic unit that culminates at 3 m asl overlain by a carbonate rich unit with strombus bubonius that culminates at 5 m asl 234 u 238 u ratios on fossil ostraea shells from both units are compatible with a marine origin from the uranium incorporated into the shells and show narrowly clustered 230 th ages respectively between 147 and 110 ka and 141 and 100 ka the two units were therefore developed during marine isotopic substage 5e miss 5e last interglacial their heights are comparable to those of contemporaneous marine deposits found in many tectonically stable areas of the world such as in the bahamas and in bermuda and can therefore be used as indicators of eustatic changes during the last interglacial it is argued that on the basis of this evidence the last interglacial was characterised by two eustatic maxima

reconstructing the terrestrial flora and marine plankton of the middle devonian of spain implications for biotic interchange and palaeogeography a rich and well preserved palynomorph assemblage from the middle devonian of northern spain is analysed with regard to palaeobiogeography and palaeocontinental reconstruction the communities of terrestrial plants dispersed spores marine zooplankton chitinozoans and marine phytoplankton acritarchs and prasinophytes all show significant endemism they are depauperate in some respects missing common species found elsewhere but also containing many endemic taxa measures of similarity and cluster analysis reveal little relatedness to other contemporary assemblages with both the spore and phytoplankton communities being sister groups to all other communities except one attempted correlation with local regional and global sea level and transgression regression schemes is complicated by the absence of key index palynomorphs in this unusual assemblage the distinctive sedimentary sequence of northern spain may reflect an increased clastic input to the marine shelf resulting from an increasingly monsoonal climate possibly connected to the kacak extinction event the assemblage9s unusual endemic character requires restrictions on dispersal the terrestrial spore assemblage suggests that large tracts of ocean existed without appreciable land bridges between the armorican terrane assemblage and laurussia to the north and gondwana to the south the phytoplankton communities support existing evidence for significant east to west ocean currents through the rheic ocean supplementary material supplementary tables 1 3 contain presence absence data for spores chitinozoans and phytoplankton respectively in various assemblages used to construct the dendrograms in figures 4 6 the tables are available at https doi org 10 6084 m9 figshare c 4726862

middle to upper pleistocene morphostructural evolution of the nw coast of sicily thermoluminescence dating and palaeontological stratigraphical evaluations of littoral deposits abstract infralittoral and terrigenous middle to upper pleistocene deposits outcropping at the nw coast of sicily gulf of castellammare and peninsula of capo san vito were investigated in order to recognise glacio eustatically caused sea level highstands and the interference between tectonics eustasy and local conditions of the coast the results originating from a stratigraphically important area were obtained by palaeontological stratigraphical analyses physical age determination with the thermoluminescence method and by detailed morphostructural studies the marine deposits situated at 3 40 m a s l mainly provide an oligotypic molluscan fauna referable to modern sgcf sfhn and sfbc biocoenoses of the infralittoral zone which live on various substrates in water of moderate to strong energy the senegalese molluscan forms providing the palaeocommunity of tyrrhenian age oxygen isotope substage 5e is comparable with the modern ap biocoenose which live on hard substrates in water of moderate energy the age determinations and estimates of the terraces indicate at most four glacio eustatic sea level highstands one perhaps two highstands between 800 ka and 250 ka isotope stages 24 8 a further event between 250 ka and 190 ka stage 7 and the youngest highstand event between 140 ka and 75 ka stage 5 the last glaciation stage 4 2 is represented by a terrigenous sequence which suggests rapid alternation of morphodynamically stable and unstable intervals as well as changes in moisture and seasonality of climate the terraces are affected by ne sw orientated faults causing brittle deformation and uplifting in rates of approximately 0 14 0 25 m ka with increasing intensity towards the east the oxygen isotope stratigraphy indicates 7 warming events during the past 800 ka the morphostructural pattern of the nw coast of sicily gives evidence for the sensible interference between local coastal conditions like sediment drift sea water currents and sediment supply on the one hand the absolute rise of eustatic sea level and the absolute uplift rate on the other hand it is obvious that eustatic oscillations deduced from deep sea sediment values does not automatically coincide with those recorded in the inner shelf area

erosion and deposition from bottom currents during the givetian and frasnian response to intensified oceanic circulation between gondwana and laurussia abstract calcareous bottom current deposits in otherwise pelagic and hemipelagic successions of the harz mountains in germany herzyn limestone formation the eastern moroccan central massif ziar mrirt nappe and the carnic alps in austria italy valentin and pal limestone formation show strong evidence of bottom current reworking of carbonate ooze during givetian and early frasnian associated phosphates confirm that higher hydraulic energy temporarily prevailed the bottom current deposited facies builds up strongly condensed and reduced successions with stratigraphic gaps which also occur with similar features in other areas of central europe and northwest africa at the same stratigraphic interval the widespread current induced reworking of calcareous sediments and phosphate formation during the givetian and early frasnian as well as the associated erosional processes marked by pronounced hiatuses all signal a major circulation event the temporal and spatial positions of these fossil calcareous contourites in the devonian are discussed research concluded that thermohaline currents were intensified by the acceleration of flows constricted in the narrow oceanic passages between the approaching continental plates laurussia and gondwana areas affected were the southeastern rhenish sea shelf the disintegrated northern continental margin of gondwana and deep marginal plateaus of the noric terrane in the western part of the prototethys the disposition of the fossil calcareous contourites and faunal data corroborate palaeogeographic reconstructions that show an advanced convergence between gondwana and laurussia and the smaller continental plates such as the armorican and noric terranes during givetian and frasnian times

holocene reef development where wave energy reduces accommodaton space kailua bay windward oahu hawaii u s a abstract analyses of 32 drill cores obtained from the windward reef of kailua bay oahu hawaii indicate that high wave energy significantly reduced accommodation space for reef development in the holocene and produced variable architecture because of the combined influence of sea level history and wave exposure over a complex antecedent topography a paleostream valley within the late pleistocene insular limestone shelf provided accommodation space for more than 11 m of vertical accretion since sea level flooded the bay 8000 yr bp virtually no net accretion 6 m coral framestone accreted at rates of 2 5 6 0 mm yr in water depths 11 m during the early holocene it abruptly terminated at 4500 yr bp because of wave scour as sea level stabilized more than 4 m of rudstone derived from the upper fore reef accreted at depths of 6 to 13 m below sea level between 4000 and 1500 yr bp coincident with late holocene relative sea level fall variations in the thickness composition and age of these reef facies across spatial scales of 10 1000 m within kailua bay illustrate the importance of antecedent topography and wave related stress in reducing accommodation space for reef development set by sea level although accommodation space of 6 to 17 m has existed through most of the holocene the kailua reef has been unable to catch up to sea level because of persistent high wave stress

sedimentary evolution of a late pleistocene temperate red algal reef coralligene on rhodes greece correlation with global sea level fluctuations autochthonous red algal structures known as coralligene de plateau occur in the modern warm temperate mediterranean sea at water depths from 20 to 120 m but fossil counterparts are not so well known this study describes from an uplifted coastal section at plimiri on the island of rhodes a 450 m long by 10 m thick late pleistocene red algal reef coralligene facies interpreted as being a coralligene de plateau and its associated deposits the coralligene facies constructed mainly by lithophyllum and titanoderma sits unconformably upon the plio pleistocene rhodes formation and is overlain by a maerl facies 2 m a mixed siliciclastic carbonate facies 0 2 m and an aeolian sand facies 2 5 m the three calcareous facies of heterozoan character are correlated with established members in the lindos acropolis formation in the north of the island while the aeolian facies is assigned to the new plimiri aeolianite formation the palaeoenvironmental and genetic stratigraphic interpretations of these mixed siliciclastic carbonate temperate water deposits involved consideration of certain characteristics associated with siliciclastic shelf and tropical carbonate shelf models such as vertical grain size trends and the stratigraphic position of zooxanthellate coral growths integration of these results with electron spin resonance dates of bivalve shells indicates that the coralligene facies was deposited during marine isotope stage 6 to 5e transgressive event ca 135 to 120 ka in water depths of 20 to 50 m and the overlying maerl facies was deposited during regression from marine isotope stage 5e to 5d ca 120 to 110 ka at water depths of 25 to 40 m the capping aeolian sand facies involving dual terrestrial subunits is interpreted as having formed during each of the glacial intervals marine isotope stages 4 71 to 59 ka and 2 24 to 12 ka with soil formation during the subsequent interglacial periods of marine isotope stages 3 and 1 respectively accumulation rates of about 0 7 mm year 1 are estimated for the coralligene facies and minimum accumulation rates of 0 2 mm year 1 are estimated for the maerl facies the existence of older red algal reefs in the plimiri region during at least marine isotope stages 7 245 to 186 ka and 9 339 to 303 ka is inferred from the occurrence of reworked coralligene type lithoclasts in the basal part of the section and from the electron spin resonance ages of transported bivalve shells

raised coral terraces at malakula vanuatu southwest pacific indicate high sea level during marine isotope stage 3 the occurrence of a series of raised coral reefs from the uplifted island of malakula vanuatu sw pacific provide an opportunity to examine sea level fluctuations over at least the past 120 000 years thirteen fossil coral samples from malakula were analyzed by the thermal ionization mass spectrometry tims u th dating technique yielding information on sea levels during late marine isotope stage 3 and early stage 4 our findings are in good agreement with sea level estimates from raised coral terraces in papua new guinea and the recent sea level reconstruction from the deep sea sedimentary 18o records in particular our coral data appear to confirm that sea levels at about 45 000 50 000 yr b p were only 30 to 60 m below the present level combined with other evidence of sea level change our data provide a strong case for much higher sea levels and therefore markedly reduced continental ice volume at 47 000 to 49 000 years ago

late quaternary reorientation of stress field and extension direction in the southern gulf of suez egypt evidence from uplifted coral terraces mesoscopic fault arrays and borehole breakouts uplifted pleistocene coral terraces and modern earthquakes show that several large normal faults are presently active in the southern gulf of suez rift basin the footwall of one of these faults is exposed at gebel el zeit where terraces at elevations of 10 18 and 42 m have been radiometrically dated as 125 ka and 426 ka respectively after correcting for eustatic sea level changes this results in net tectonic uplift rates of about 0 1 m kyr published interpretations and our own observations indicate that the average extension direction during the miocene to pliocene synrift history was 055 analysis of borehole breakouts and published earthquake fault plane solutions however suggests that the present day stress field in the southern gulf has a 010 020 shmin orientation detailed structural observations show that a change in extension direction occurred in the late pleistocene with rotation of the stress field beginning prior to formation of the 125 ka terraces but after formation of older pleistocene terraces whose ages are less tightly constrained using a horizontal slip direction of 015 and our observed net footwall uplift rate we calculate a separation velocity between sinai and africa of 0 8 1 2 m kyr the proposed pleistocene change in extension direction in the gulf of suez corresponds closely with the post 500 ka change in extension direction documented in the kenyan rift system and a similar change in extension direction recorded in the central red sea these regional similarities in tectonic history suggest that the underlying causes of these events may be a plate scale phenomenon affecting the entire afro arabian rift system rather than local changes in the quaternary stress field

sequence stratigraphy and a revised sea level curve for the middle devonian of eastern north america abstract the well exposed middle devonian rocks of the appalachian foreland basin onondaga formation hamilton group tully formation and the genesee group of new york state preserve one of the most detailed records of high order sea level oscillation cycles for this time period in the world detailed examination of coeval units in distal areas of the appalachian basin as well as portions of the michigan and illinois basins has revealed that the pattern of high order sea level oscillations documented in the new york pennsylvania section can be positively identified in all areas of eastern north america where coeval units are preserved the persistence of the pattern of high order sea level cycles across such a wide geographic area suggests that these cycles are allocyclic in nature with primary control on deposition being eustatic sea level oscillation as opposed to autocylic controls such as sediment supply which would be more local in their manifestation there is strong evidence from studies of cyclicity and spectral analysis that these cycles are also related to milankovitch orbital variations with the short and long term eccentricity cycles 100 kyr and 405 kyr being the dominant oscillations in many settings relative sea level oscillations of tens of meters are likely and raise considerable issues about the driving mechanism given that the middle devonian appears to record a greenhouse phase of phanerozoic history these new correlations lend strong support to a revised high resolution sea level oscillation curve for the middle devonian for the eastern portion of north america recognized third order sequences are eif 1 lower onondaga formation eif 2 upper onondaga and union springs formations eif giv oatka creek formation giv 1 skaneateles giv 2 ludlowville giv 3 lower moscow giv 4 upper moscow lower tully and giv 5 middle tully geneseo formations thus in contrast with the widely cited eustatic curve of johnson et al 1985 which recognizes just one major transgressive regressive t r cycle in the early mid givetian if prior to the major late givetian taghanic unconformity iia upper tully geneseo shale we recognize four t r cycles if restricted ig ih and ii we surmise that third order sequences record eustatic sea level fluctuations of tens of meters with periodicities of 0 8 2 myr while their medial scale fourth order subdivisions record lesser variations primarily of 405 kyr duration long term eccentricity this high resolution record of sea level change provides strong evidence for high order eustatic cycles with probable milankovitch periodicities despite the fact that no direct evidence for middle devonian glacial sediments has been found to date

the analysis of last interglacial mis 5e relative sea level indicators reconstructing sea level in a warmer world the last interglacial mis 5e 128 116 ka is among the most studied past periods in earth s history the climate at that time was warmer than today primarily due to different orbital conditions with smaller ice sheets and higher sea level field evidence for mis 5e sea level was reported from thousands of sites but often paleo shorelines were measured with low accuracy techniques and in some cases there are contrasting interpretations about paleo sea level reconstructions for this reason large uncertainties still surround both the maximum sea level attained as well as the pattern of sea level change throughout mis 5e such uncertainties are exacerbated by the lack of a uniform approach to measuring and interpreting the geological evidence of paleo sea levels in this review we discuss the characteristics of mis 5e field observations and we set the basis for a standardized approach to mis 5e paleo sea level reconstructions that is already successfully applied in holocene sea level research application of the standard definitions and methodologies described in this paper will enhance our ability to compare data from different research groups and different areas in order to gain deeper insights into mis 5e sea level changes improving estimates of last interglacial sea level is in turn a key to understanding the behavior of ice sheets in a warmer world

stratigraphy palaeoenvironments and model for the deposition of the abdur reef limestone context for an important archaeological site from the last interglacial on the red sea coast of eritrea stone tools discovered within uplifted marine terraces along the red sea coast of eritrea at the abdur archaeological site dated to 125 7 ka the last interglacial marine isotope stage 5e show that early humans occupied coastal areas by this time walter et al 2000 nature 405 65 69 in the present paper the stratigraphy facies types and faunal composition from 25 measured sections of the tool bearing abdur reef limestone arl are documented in detail and interpreted to provide a palaeoenvironmental context for the stone artefacts and a model for the deposition of the arl the arl represents a complex marine terrace sequence erosional surfaces indicative of interrupted sedimentation are locally observed at two levels within the arl they subdivide the complex into three subunits named 5e1 5e2 and 5e3 representing different stages of the marine isotope stage 5e sea level highstand comprising six depositional phases i vi of the arl subunit 5e1 begins with the initial transgression of the 5e sea level highstand leading to the deposition of widespread lag gravels on which rich oyster beds developed in shallow water phase i it further records rapid deepening accompanied by the deposition of low energy carbonates with scarce corals phase ii and later shoaling characterised by local development of a fringing reef tract in a sedimented environment phase iii subunit 5e1 is capped locally by a burrowed hardground that is laterally equivalent to depositional discontinuities interpreted as caused by a globally recognised mid 5e sea level low stand phase iv extensive reef build up in response to sea level rise and improved conditions for coral growth characterises subunit 5e2 phase v a possible second sea level drop during the 5e highstand is inferred from the oyster encrusted upper surface of subunit 5e2 subunit 5e3 encompasses restricted coral patches that developed on the upper surface of the underlying subunit during the last stage of the 5e marine high stand phase vi two different toolkits are found in the arl one consists of bifacial hand axes and cores of the acheulian industry typically associated with the oyster beds encrusted on the transgressive lag deposits the other consists of middle stone age msa type obsidian flakes and blades mainly found in the nearshore and beach environments alongside debris from marine invertebrates and large land mammals the distribution of these tools suggests that foraging activities of early humans varied with environmental setting the abdur archaeological site represents a late example of the acheulian msa transition seen as a benchmark for early modern human behaviour and is to date the earliest well dated example of early human adaptation to marine food resources

last interglacial sea stands on barbados and an early anomalous deglaciation timed by differential uplift three major sea level maxima between 137 and 120 kyr b p are documented by surveys of pairs of wave cut notches and other features associated with the broadly defined last interglacial coral terrace on barbados regression analysis of elevation differences between notch pair members as a function of their uplift rates at seven sites yields the age difference between first and third sea stands and their eustatic sea level difference these results when combined with stratigraphic data from the bahamas bermuda and western australia and a chronology based on age limits of corals from the bahamas and western australia yield an endpoint age and eustatic low tide elevation of 136 7 kyr b p and 7 4 m respectively for the first sea stand 126 kyr b p and 5 6 m for the second and 120 5 kyr b p and 3 0 m for the third the first sea stand is the result of an anomalous deglaciation that was completed during low northern summer milankovitch insolation this is contrary to the milankovitch hypothesis that orbitally controlled insolation largely determines the variations of glacial ice volume it implies that internal factors within the earth s climate system can be much stronger than the effects of insolation variations

timing and warmth of the last interglacial period new u series evidence from hawaii and bermuda and a new fossil compilation for north america abstract the timing and duration of the last interglacial period have been controversial with some studies suggesting a relatively short duration that is orbitally forced and others suggesting a long duration that is at most only partly related to orbital forcing new high precison thermal ionization mass spectrometric tims u series ages of last interglacial corals from hawaii and bermuda test these competing hypotheses waimanalo formation corals from slowly uplifting oahu hawaii range in age from 134 to 113 ka with most ages between 125 and 115 ka combined with published u series ages from nearby lanai the data suggest a long last interglacial period that may have occurred from 136 to at least 115 ka the results indicate that orbital forcing may not have been the only control on ice sheet growth and decay because sea level would have been high at times of relatively low northern hemisphere summer insolation on tectonically stable bermuda deposits from the 200 ka penultimate interglacial period 120 ka peak last interglacial period and 80 ka late last interglacial period high sea stands have been newly dated fossil corals on bermuda are derived from patch reefs that likely were catch up responses to sea level rise it is expected that u series ages of last interglacial corals on bermuda should overlap with but not be as old as the range of corals on oahu last interglacial corals on bermuda give a range of 125 113 ka which supports this hypothesis a large number of emergent marine deposits on hawaii bermuda and along coastal north america have now been dated to the last interglacial period both oahu and bermuda have marine invertebrate faunas with a number of extralimital southern species of mollusks suggesting warmer than present waters during the last interglacial period warmer waters are also suggested for last interglacial localities around most of north america from florida to canada and greenland and baja california to alaska these observations are consistent with similar warm water faunas of last interglacial age reported from japan the mediterranean basin and western australia it is likely that significant changes in ocean currents took place during the last interglacial period with a movement of relatively warm waters to higher latitudes than is the case today

coral reefs and sea level change abstract coral reefs provide significant evidence for former sea level positions because of their geological preservation and suitability for dating interpretation of this evidence presumes an understanding of reef geomorphology modern reef organism distributions and environmental factors influencing them fossil reef terraces formed during the last interglacial marine oxygen isotope mis substage 5e 128 116 ka are prevalent on many tropical shorelines and there has been ongoing debate as to the height reached by sea level during that highstand observations from numerous last interglacial sites suggest that sea level was at least 3 m above present sea level implying less extensive icesheets than at present an elevation of 6 m has commonly been adopted when correcting tectonically active sites for uplift recent compilations suggest elevations up to 8 9 m but incorporate few observations from reefs where the last interglacial is found below sea level oscillation of sea level during mis 5e has been interpreted from several sites with recent studies inferring rapid rise of several metres at the end of the interglacial these interpretations are at the limits to the precision with which corals can currently be dated and their palaeo water depths inferred it is not surprising that constraining last interglacial sea level changes within uncertainties of less than 1 2 m remains controversial considering sea level variations recognised between reef sites in the holocene and observed geographical variation in isostatic or flexural adjustments fossil coral reefs on uplifting margins also provide clear evidence for mis substages 5c and 5a and those on huon peninsula indicate fluctuations related to heinrich events mis 3 interpretations show considerable variability between sites with still greater uncertainties about sea level timing and elevation during previous interglacials future study of extensive sequences of fossil reefs preserved on rapidly subsiding margins could address these uncertainties submerged reefs have already yielded important information about sea level rise during the last deglaciation coring around barbados and tahiti as well as on the huon peninsula has produced a broadly consistent picture of ice melt reflecting eustatic change since the last glacial maximum these studies have shown the sensitivity of reefs to rapid sea level rise associated with meltwater pulses with some reefs drowning while others back stepped integrated ocean drilling program iodp expeditions to tahiti and recently the great barrier reef extended these records but details of timing nature and impact of deglacial meltwater pulses remain elusive studies of holocene reefs have indicated different growth strategies some kept up with sea level while others caught up when sea level decelerated holocene sea level appears to have experienced a gradual rise up to present across the caribbean providing accommodation space for reefs to accrete vertically whereas in the indo pacific sea level has been near its present level since 7 ka with many reef flats emergent following a slight fall of sea level caused by ocean siphoning microatolls on reef flats provide perhaps the clearest evidence of past sea level position but in their absence novel biological or other sea level indicators are required to better constrain palaeo water depths there is an urgent need for further research from additional key reef locations not only to decipher processes driving past sea level change and its geographical variability but also to better understand how coral reefs will respond in the context of future sea level rise

global sea level fluctuations during the last interglaciation mis 5e the geomorphology and morphostratigraphy of numerous worldwide sites reveal the relative movements of sea level during the peak of the last interglaciation marine isotope stage mis 5e assumed average duration between 13072 and 11972 ka because sea level was higher than present deposits are emergent exposed and widespread on many stable coastlines correlation with mis 5e is facilitated by similar morphostratigraphic relationships a low degree of diagenesis uranium thorium u th ages and a global set of amino acid racemization aar data this study integrates information from a large number of sites from tectonically stable areas including bermuda bahamas and western australia and some that have experienced minor uplift 2 5 m 100 ka including selected sites from the mediterranean and hawaii significant fluctuations during the highstand are evident at many mis 5e sites revealed from morphological stratigraphic and sedimentological evidence rounded and flat topped curves derived only from reef tracts are incomplete and not representative of the entire interglacial story despite predictions of much different sea level histories in bermuda the bahamas and western australia due to glacio and hydro isostatic effects the rocks from these sites reveal a nearly identical record during the last interglaciation the last interglacial highstand is characterized by several defined sea level intervals slis that include sli 1 post glacial mis 6 5e termination ii rise to above present before 130 ka sli 2 stability at 2 to 3 m for the initial several thousand years 130 to 125 ka during which fringing reefs were established and terrace morphology was imprinted along the coastlines sli 3 a brief fall to near or below present around 125 ka sli 4 a secondary rise to and through 3 4 m 124 to 122 ka followed by sli 5 a brief period of instability 120 ka characterized by a rapid rise to between 6 to 9 m during which multiple notches and benches were developed and sli 6 an apparently rapid descent of sea level into mis 5d after 119 ka u th ages are used to confirm the last interglacial age of the deposits but unfortunately in only two cases was it possible to corroborate the highstand subdivisions using radiometric ages sea levels above or at present were relatively stable during much of early mis 5e and the last 6 7 ka of mis 1 encouraging a comparison between them the geological evidence suggests that significant oceanographic and climatic changes occurred thereafter midway through and continuing through the end of mis 5e fluctuating sea levels and a catastrophic termination of mis 5e are linked to the instability of grounded and marine based ice sheets with the greenland gis and west antarctic wais ice sheets being the most likely contributors late mis 5e ice volume changes were accompanied by oceanographic reorganization and global ecological shifts and provide one ominous scenario for a greenhouse world r 2007 elsevier ltd all rights reserved