late pleistocene sea level change in the bahamas from mass spectrometric u series dating of submerged speleothem abstract the dating of sea level events by a method independent of orbital tuning techniques and the marine foraminiferal isotopic record provides a test of both the dating of the marine record and the strength and nature of the relationship between climatic change sea level change and milankovitch cycles dating of fossil corals and submerged speleothem provides such independent information results of thermal ionization mass spectrometric u series dating on layers of flowstone speleothem from lucayan caverns grand bahama island indicate that multiple sea level events have passed through a depth of 10 to 15 m below modern sea level during the last 300 000 years these data are used to constrain the magnitude and timing of sea level fluctuations during the late pleistocene the new sea level curve constructed from these data correlates closely with the marine isotopic record sea level peaks occurred at around 233 215 125 and 100 ka bp there is no evidence at the depth from which this speleothem was retrieved of any high sea stands at 195 or 80 ka corresponding to the foraminiferal 7a and 5a oxygen isotope peaks there is also no evidence of a double rise around the 125 ka 5e peak although such an oscillation could have occurred above 10 m leaving no record in the lucayan caverns speleothem

sea level records at 80 ka from tectonically stable platforms florida and bermuda studies from tectonically active coasts on new guinea and barbados have suggested that sea level at 80 ka was significantly lower than present whereas data from the atlantic and pacific coasts of north america indicate an 80 ka sea level close to that of the present we determined ages of corals from a shallow submerged reef off the florida keys and an emergent marine deposit on bermuda both localities are on tectonically stable platforms distant from plate boundaries uranium series ages show that corals at both localities grew during the 80 ka sea level highstand and geologic data show that sea level at that time was no lower than 7 9 m below present florida and may have been 1 2 m above present bermuda the ice volume discrepancy of the 80 ka sea level estimates is greater than the volume of the greenland or west antarctic ice sheets comparison of our ages with high latitude insolation values indicates that the sea level stand near the present at 80 ka could have been orbitally forced

post glacial sea level rise from a coral record at huon peninsula papua new guinea dating of coral reef terraces can provide a record of changes in sea level which should be pronounced during the transition between glacial and interglacial periods cores drilled from coral reefs at barbados in the equatorial west atlantic1have revealed the sea level changes that occurred during the younger dry as event at the end of the last glacial maximum 11 000 yr bp it has not been known however whether pacific coral reefs can grow at a rate sufficient to keep up with the rise in sea level during such a transition here we report results obtained from a 52 m drill core from the post glacial reef at huon peninsula papua new guinea spanning the interval from 7 000 to 11 000 14c yr bp which show that coral growth kept pace while the relative sea level rose by 50m although the tectonic environment is very different from that at barbados the two records compare well when corrections are made for local tectonic uplift showing that sea level rise was similar at both locations the rate of rise was greatest between 9 000 and 10 00014c yr bp corresponding to the time of the younger dryas

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

record of mis 5 sea level highstands based on u th dated coral terraces of haiti abstract new geomorphologic investigations and new u th series dates from haiti northwestern peninsula confirm the age of coral reef terraces assigned to mis 5 5 130 ka mis 5 3 107 ka and mis 5 1 83 ka sea level peaks they also provide evidence for a second high sea level occurring some thousand years before 118 ka and indicate a second mis 5 1 sea level stand at about 76 ka these results are in agreement with the raised terraces of barbados although the staircase of haiti consists of four steps compared to eight the haitian sequence can be compared with the maximal number of distinct mis 5 sea level highstands recorded in the world from coral reef tracts and their relative height above or below present sea level three mis 5 5 sea level changes have been recognized with sea level oscillating above or near the present level until 122 ka only dropping then rising to 11 m below present sea level at 120 ka three high frequency sea level oscillations occurred during mis 5 3 and a fourth during mis 5 3 5 2 two or three events may have occurred during mis 5 l according to whether the 73 ka event is considered to belong to mis 5 1

predicted bounds on peak global mean sea level during marine isotope stages 5a and 5c abstract estimates of marine isotope stage mis 5c and 5a global mean sea level gmsl based on marine terraces and coastal indicators range from 15 37 m and 9 30 m below present respectively tectonic displacement and glacial isostatic adjustment gia complicate efforts to refine this range we revisit this issue using numerical predictions of post glacial sea level change and updated estimates of site specific tectonic signals based upon these predictions laurentide and cordilleran peripheral bulge dynamics and variations in the gravitational effect of these ice masses dominate the gia signal along the east and west coasts of north america published compilations suggest that mis 5 sea level indicators extending from virginia to the caribbean lie on the outer flank of the peripheral bulge while those along a transect from oregon to baja california sit on the inner flank of the bulge our gia modeling reconciles these data by adopting a significantly weaker i e lower viscosity upper mantle in analyzing data on the pacific coast relative to the atlantic an inference supported by seismic tomography we present a sensitivity analysis that compares the observed elevation of globally distributed high stand markers to a suite of gia simulations that vary the earth model and gmsl from the last interglaciation mis 5e 130 115 ka to 70 ka we conclude that gmsl peaked at 8 5 4 6 m 1 during mis 5a and 9 4 5 3 m during mis 5c a more restrictive analysis yields slightly wider bounds corresponding to 10 5 5 5 m and 11 1 6 6 m respectively

a glacial isostatic adjustment origin for double mis 5 5 and holocene marine notches in the coastline of italy abstract modern tidal notches on rocky coastlines are well developed in the mediterranean sea because of its microtidal regime and occur around much of the coast of italy uplifted fossil notch couplets here called double notches are well developed in some sites the two notches within a couplet have an average vertical separation of 2 4 m and are systematically observed at an elevation of a few metres above present sea level on tectonically stable coastal sites of western italy the upper notch has a morphology similar to that of the notch developed at present day mean sea level in the modern tidal regime however the lower notch has a smoother morphology and larger vertical dimension than the upper one and is pervasively bored by lithophaga activity although the upper notch is attributed to the mis 5 5 stage last interglacial 125 ka the origin of the lower one has so far remained enigmatic based on a quantitative assessment of the glacial isostatic adjustment gia expected at each single site from updated models we argue that both notches within a couplet were formed during a single highstand of the mis 5 5 substage and the superposed morphology resulted from isostatic motion and tidal erosion the lower notch of the couplet is argued to be formed during the earlier part of the highstand and its smooth vertically extended morphology is attributed to glacio hydro isostatic vertical movements crustal subsidence that extended tidal erosion over a large vertical distance as the crust slowly subsided in contrast the upper notch of the couplet is considered to develop in the later part of the highstand due to tidal action at times when eustatic and isostatic movements almost ceased the ridge between the two notches in a couplet was the site of organic encrustation protecting the rock there but subsequently removed by subaerial erosion when the notch couplet was uplifted observations of double notches formed on the present coastline show that a similar process has been active also during the late holocene transgression

elevation of the last interglacial highstand in sicily italy a benchmark of coastal tectonics well preserved mis 5 5 terraces in sicily are identified primarily by the index fossil strombus bubonius and dated by amino acid racemization aar electron spin resonance esr uranium thorium u th and thermo luminescence tl methods this review of published data and new results for the island of sicily and neighbouring small islands of egadi ustica and lampedusa identifies areas of rapid uplift in the east up to 175 m elevation above sea level slower uplift in the north 29 m and relative stability in the northwest 2 18 m in contrast about 250 km of the southern coastline of sicily does not appear to contain mis 5 5 outcrops in eastern sicily correlation of mis 5 5 highstands is based on strombus bubonius discovered at 86 m and correlated with the inner margin terrace at 110 m in the taormina area a fossiliferous marine conglomerate on a terrace with an inner margin at 115 m occurs in an area with undated terrace morphology and elevation data based on esr methodology applied to fossils sampled at 105 m in taormina we attribute this terrace to mis 5 probably 5 5 this age allows us to constrain the date of one point along a very long coastline that is otherwise undated a newly discovered fossil beach between 7 and 9 m at cefalu north central sicily attributed to mis 5 1 5 3 using aar analysis permits correlation of mis 5 5 to a 29 m high tidal notch geomorphologically related to a terrace at the same elevation cefalu lies in an important position between the uplifted coastline of northeastern sicily and the more stable coastline of western sicily this compilation of mis 5 5 data for all of sicily reflects the active tectonics of eastern sicily in contrast to the rest of the island

last glacial sea level change deduced from uplifted coral terraces of huon peninsula papua new guinea we have dated corals sampled from the uplifted terraces of huon peninsula papua new guinea that grew during the marine isotope stage 3 to reconstruct sea levels of the last glacial period from 30 to 55 ka kiloannum mass spectrometric u series dating methods resulted in high precision dates and could also be used to recognize diagenetically altered samples the only quantitative test of open systembehaviour of both uraniumand thoriumisotopes involves the com parison of 234 u 238 u ratios at the time of coral growth with present sea water values additional tests included checks for systematic variations in stable isotopes x ray diffraction to detect calcification and petrographic examination sea levels were corrected for glacio hydro isostatic variations and also for the depth range of coral growth habitat sea levels from30 to 55 ka were approxim ately 80 mlower than present superimposed on this general trend four periodic sea level high stands were found at 6 8 ka intervals approximately at 30 38 44 and 52 ka that appear to be synchronous with rapid climate variations previously observed in ice cores and in deep sea sediments r 2001 elsevier science ltd and inqua all rights reserved

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

reconciliation of sea level observations in the western north atlantic during the last glacial cycle abstract a south to north gradient of increasing marine isotope substage mis 5a 80 ka bp sea level has been recorded across the caribbean and surrounding region relative to present mis 5a sea levels range from 19 m to more than 3 m between barbados haiti the bahamas florida bermuda and the us atlantic coast in contrast no gradient in sea level is observed for the last interglacial period mis 5e 128 118 ka bp at tectonically stable localities in the same region with deposits generally lying several metres above present we demonstrate here that these controversial observations are reconciled by taking into account the isostatic response of the earth to glacial loading and unloading a fundamental effect that is commonly overlooked in the interpretation of sea level observations from different locations to define a global sea level curve furthermore the observed gradient can be used to place constraints on earth rheology and is an important indicator of the behaviour of the north american ice sheets during the last glacial cycle

late quaternary development of the croatan beach ridge complex bogue sound bogue banks nc usa and implications for coastal evolution abstract foraminiferal sedimentological geophysical and geochronologic data were utilized to elucidate the late quaternary geologic development of the croatan beach ridge complex cbrc bogue sound and bogue banks north carolina usa the cbrc is a relict beach ridge feature located on the mainland it is separated from the modern barrier island bogue banks by bogue sound seventeen cores along shore normal and shore parallel transects provided material for sedimentologic and foraminiferal analysis and resulted in the recognition of seven depositional facies representing a variety of coastal depositional environments chronologic and depositional facies data suggest the cbrc was initiated during mis 5a and rapid southward progradation produced a cape structure eolian reactivation of the upper sand of the cbrc occurred during the last glacial maximum 18 ka the age of flood tide delta deposits in bogue sound suggests that the holocene barrier island bogue banks had formed by 6 ka shoreface ravinement resulted in a shoreface landward of the present shoreline by 3 5 ka seaward and westward spit progradation of bogue banks began 1 7 ka and continued to 1 3 ka normal marine salinity conditions were present in bogue sound 1 1 ka suggesting removal of at least the narrowest parts of the barrier island coeval with a previously documented segmentation of the southern outer banks barrier islands previous work has linked this segmentation to climate warming and increased tropical storm activity during the medieval climate anomaly this study illustrates the complex response of this coastal system to pleistocene and holocene sea level and climate change over two major sea level cycles in particular the regional geomorphology during mis5a and the holocene sea level highstand differ significantly and this in large part was controlled by the antecedent geologic framework resulted in the contrasting more localized coastal geomorphic response

mantle dynamics postglacial rebound and the radial viscosity profile abstract we infer the radial viscosity structure of the earth s mantle from observations of long wavelength geoid glacially induced sea level changes and changes in the earth s rotation and gravitational field we employ a combination of forward and formal inverse modeling of long term mantle circulation driven by large scale density differences deduced from seismic tomography based on the resulting unscaled mantle viscosity profiles we model the time dependent glacial isostatic adjustment of the earth related to past and present changes in the ice ocean mass imbalance and we deduce scaled mantle viscosity profiles which simultaneously fit the long wavelength geoid constraint and glacially induced changes of the earth s shape three mantle viscosity profiles are fitting the observational data equally well all profiles are characterized by a two order of magnitude variation of viscosity within the earth s mantle variations of viscosity in the upper mantle are less than one order of magnitude in the lower mantle the viscosity differs significantly with depth for all models average viscosities in the upper and lower mantle are around 2 5 1020 and 1 3 1022 pa s respectively

deglaciation of a soft bedded laurentide ice sheet we present a series of numerical reconstructions of the laurentide ice sheet during the last deglaciation 18 7 14c ka that evaluates the sensitivity of ice sheet geometry to subglacial sediment deformation these reconstructions assume that the laurentide ice sheet flowed over extensive areas of water saturated deforming sediment soft beds corresponding to the st lawrence lowland the great lakes region the western prairies of the u s and canada and the hudson bay and hudson strait regions sediment rheology is based on a constitutive law that incorporates experimental results from late wisconsin till deposited by the laurentide ice sheet which suggest only mildly nonlinear viscoplastic behavior by varying the effective viscosity of till we produced four reconstructions for the ice sheet during the last glacial maximum 18 14c ka and two reconstructions each of the ice sheet at 14 13 12 11 and 10 14c ka we also produced one reconstruction for 9 8 4 8 and 7 14c ka reconstructions that assume a low effective viscosity for all areas of deforming sediment show a multidomed ice sheet with a large bowl shaped depression over hudson bay and thin ice 1000 m above modern sea level over the western and southern margins those reconstructions that assume a higher effective viscosity of till in the hudson bay region than for the western and southern margins also show a multidomed ice sheet but with considerably thicker ice over hudson bay and a more northerly position of the central ice divide these two different geometries may represent ice sheet orographic changes associated with a heinrich event further increases in effective viscosity of till approaching the effective viscosity of ice would result in a high monolithic ice dome centered over hudson bay reinforcing the notion that a multidomed ice sheet reflects the distribution of substrate geology modeled ice surface geometry at the last glacial maximum shows many of the same general features as previous reconstructions that incorporate deformable beds our reconstructions with higher effective till viscosities in hudson bay also agree with the ice 4g reconstructions peltier 1994 which are based on inversion of relative sea level data for the early part of the last deglaciation 18 13 14c ka but then depart significantly from ice 4g beginning at about 12 14c ka due to differing assumptions of the history of deglaciation modeled ice volume for the last glacial maximum suggests a glacioeustatic change of 50 55 m by a soft bedded laurentide ice sheet this would increase as the effective viscosity of till increases subsequent ice volume changes through the last deglaciation generally parallel the trend of eustatic rise recorded at barbados new guinea and tahiti but suggest that the laurentide ice sheet was not the source of meltwater pulse 1a

late quaternary marine isotope stages 6 1 seismic sequence stratigraphic evolution of the otago continental shelf new zealand abstract a proposed chronostratigraphic model for the late quaternary evolution of the otago continental shelf new zealand includes fluvially incised sequence boundaries eroded during marine isotope stages 2 4 and 6 bounding three sequences subdivided into lowstand transgressive and highstand regressive systems tracts datable material is limited to the uppermost 1 m of the sequence and consequently the model is based on correlation of new high resolution seismic reflection data geopulse to a compilation of independent global sea level curves a second chronostratigraphic model that lacks a stage 4 sequence boundary and distinct stage 3 highstand forced regressive deposit is discounted because its subsidence corrected paleoshoreline depths do not match lowstands in the eustatic curves or temporally constrained sequences at other far field locations in the preferred chronostratigraphic model sea level lowstands during stages 2 4 and 6 reached maximum depths of 126 131 m 101 111 m and 116 135 m respectively producing sequence boundaries landward pinching deltaic wedges on the outer otago shelf and submarine canyon incision lowstand paleoshoreline depths have been corrected for subsidence from thermal cooling sediment compaction and loading but may be erroneously deep owing to erosion of paleoshoreline indicators clastic shallow marine wedges and back barrier valley fill deposits accumulated during the stage 6 5 4 3 and 2 1 marine transgressions contrary to the traditional sequence stratigraphic model deltaic and strandline units deposited during highstand through falling sea level stages 5 4 3 2 1 volumetrically dominate otago late quaternary sequences discrete units and minor marine erosion surfaces within the transgressive and regressive systems tract deposits are interpreted as strong evidence for seventh 20 ka or higher order sea level fluctuations influencing sedimentation on the otago shelf

speleothem constraints on marine isotope stage mis 5 relative sea levels yucatan peninsula mexico rates of sea level fall at the termination of the last interglacial are poorly defined and archives from which sea level elevations are constrained during marine isotope stage mis 5 in the western north atlantic caribbean region are restricted spatially to a few key sites here growth periods of presently submerged but subaerially deposited speleothems from the yucatan peninsula south east mexico are dated using the 230 th 234 u multi collector inductively coupled plasma mass spectrometric method the growth periods used to constrain maximum elevations of relative sea level are in agreement with glacio isostatic adjustment models for the near to intermediate region of the former north american ice sheets furthermore our data provide additional constraints on the timing of peak relative sea levels during mis 5a and 5c and the timing of the regression following the last interglacial highstand combining our data with coral archives of minimum relative sea level from the same region provides a novel approach to calculating the rate of relative sea level fall although initial estimates are poorly constrained because of the wide range in ages observed for the most suitable corals copyright 2013 john wiley sons ltd

identification of a 15 m wisconsin shoreline on the texas inner continental shelf abstract the maximum sea level position during the middle wisconsin oxygen isotope stage 3 is controversial it being interpreted as anywhere from at or above present day levels to 85 m high resolution seismic lithologic paleontologic and radiocarbon data from the east texas continental shelf were used to map a stage 3 shoreline the shoreline was placed in a regional context with a study of the texas shelf based on seismic profiles core and platform boring descriptions that identifies the stage 3 maximum flooding surface and the stage 2 sequence boundary these surfaces were then traced up dip on the east texas shelf where a shore parallel escarpment was recognized landward of the escarpment the stage 3 maximum flooding surface is amalgamated with the stage 2 sequence boundary therefore the location of the escarpment marks the up dip limit of stage 3 deposits and a stage 3 shoreline lagoonal sediments with in situ brackish water fossils on lap the escarpment seaward of the escarpment remnants of barrier island facies have been preserved as a bank freeport rocks bathymetric high located in 18 m of water the shoreline adjusted for subsidence is located at 15 2 m which is shallower than what oxygen isotope and coral records indicate

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

quaternary fluvial history of the delaware river new jersey and pennsylvania usa the effects of glaciation glacioisostasy and eustasy on a proglacial river system abstract fluvial glacial and estuarine deposits in the delaware valley record the response of the delaware river to glaciation sea level change and glacioisostasy during the quaternary incision following an early pleistocene glaciation created the present valley which is inset into a pliocene strath and fluvial plain middle and upper pleistocene and holocene deposits were laid down in this inset valley estuarine terraces in the lower valley and bayshore at 20 m probably marine isotope stage mis 11 8 m mis 5e and 3 m mis 5a or c and a fluvial deposit that correlates to offshore mis 3 marine deposits at 20 m are at elevations consistent with glacioisostatic models successive incisions during lowstands in the middle and late pleistocene lengthened deepened and narrowed the channel in the lower valley and shifted the channel westward in delaware bay during mis 2 glaciation from 25 to 18 ka the delaware was diverted to the hudson shelf valley by glacioisostatic tilting most glacial sediment was trapped in fluvial lacustrine valley fills north of the terminal moraine incision of the valley fill was accomplished during the early stage of rebound between 17 and 12 ka drainage to the delaware shelf was restored between 15 and 13 ka as the forebulge collapsed during incision multiple postglacial terraces formed where the valley was perpendicular to rebound contours and so was steepened and elevated northward and a single terrace formed where the valley paralleled the contours and there was no differential elevation or steepening about 65 of the original volume of mis 2 glacial sediment remains in the main valley and most of the eroded volume is in the channel in the lower valley beneath holocene estuarine fill little glacial sediment reached the delaware or hudson shelf overbank deposition on the lower postglacial terrace and modern floodplain spans the holocene the volume of holocene sediment in the estuary and bay yields a basinwide denudation rate of about 20 m my

coastal tectonics on the eastern margin of the pacific rim late quaternary sea level history and uplift rates channel islands national park california usa abstract the pacific rim is a region where tectonic processes play a significant role in coastal landscape evolution coastal california on the eastern margin of the pacific rim is very active tectonically and geomorphic expressions of this include uplifted marine terraces there have been however conflicting estimates of the rate of late quaternary uplift of marine terraces in coastal california particularly for the northern channel islands in the present study the terraces on san miguel island and santa rosa island were mapped and new age estimates were generated using uranium series dating of fossil corals and amino acid geochronology of fossil mollusks results indicate that the 2nd terrace on both islands is 120 ka and the 1st terrace on santa rosa island is 80 ka these ages correspond to two global high sea stands of the last interglacial complex marine isotope stages mis 5 5 and 5 1 respectively the age estimates indicate that san miguel island and santa rosa island have been tectonically uplifted at rates of 0 12 0 20 m ka in the late quaternary similar to uplift rates inferred from previous studies on neighboring santa cruz island the newly estimated uplift rates for the northern channel islands are however an order of magnitude lower than a recent study that generated uplift rates from an offshore terrace dating to the last glacial period the differences between the estimated uplift rates in the present study and the offshore study are explained by the magnitude of glacial isostatic adjustment gia effects that were not known at the time of the earlier study set in the larger context of northeastern pacific rim tectonics channel islands uplift rates are higher than those coastal localities on the margin of the east pacific rise spreading center but slightly lower than those of most localities adjacent to the cascadia subduction zone the uplift rates reported here for the northern channel islands are similar to those reported for most other localities where strike slip tectonics are dominant but lower than localities where restraining bends such as the big bend of the san andreas fault result in crustal shortening

marine terraces and rates of vertical tectonic motion the importance of glacio isostatic adjustment along the pacific coast of central north america differences in marine terrace elevations across the pacific coast of north america have long been assumed to be a result of differences in the rates of tectonic motion however other processes particularly glacio isostatic adjustment lead to regional variations in sea levels in this study we compiled the elevations of marine isotope stage mis 5e ca 119 129 ka 5c ca 106 ka and 5a ca 84 ka terraces across the pacific coast of central north america and compared these regional variations in elevation with model predictions of glacio isostatic adjustment after correcting for tectonics these predictions are generally consistent with the observed trends in the elevations of the terraces and show that this process created up to 20 m of coeval variation in local sea levels along the pacific coast of central north america between 20 n and 45 n during mis 5c and mis 5a but less 4 m during mis 5e accounting for glacio isostatic adjustment reduces the variability in uplift rates calculated at individual locations using different aged terraces as datums ignoring glacio isostatic adjustment leads to overestimated uplift rates by an average of 40 but up to 72 across the pacific coast of central north america an understanding of regional variations in glacio isostatic adjustment corrected sea levels also contributes to the correct identification of marine terraces with mistaken ages

anomolous multi origin marine notch sites three case studies in the central mediterranean sea abstract we present and discuss the genesis age and evolution of indented landforms carved at sea level in correspondence of carbonatic headlands in three sites of the central mediterranean coasts between marseille france and balzi rossi italy the island of tavolara sardinia italy and the promontory of tindari sicily italy the shape of these anomalous notches landforms can be referred to is very similar to tidal notches despite their genesis and morphometric parameters are different from those suggested by other authors for the central mediterranean area two of these sites are located in tectonically stable areas while the third falls is located in an uplifting area those the notches we investigated along the coast of southern france are submerged notch type landforms located in the vicinities surroundings of current modern tidal notches at tavolara island these anomalous notches are placed at about 25 m b s l these landforms and have the shape of mushroom like notches finally those investigated along the metamorphic carbonatic promontory of tindari are marine and abrasional notches that have been uplifted likely during the holocene

late quaternary uplift along the north america caribbean plate boundary evidence from the sea level record of guantanamo bay cuba abstract the tectonic setting of the north america caribbean plate boundary has been studied intensively but some aspects are still poorly understood particularly along the oriente fault zone guantanamo bay southern cuba is considered to be on a coastline that is under a transpressive tectonic regime along this zone and is hypothesized to have a low uplift rate we tested this by studying emergent reef terrace deposits around the bay reef elevations in the protected inner part of the bay are 11 12 m and outer coast wave cut benches are as high as 14 m uranium series analyses of corals yield ages ranging from 133 ka to 119 ka correlating this reef to the peak of the last interglacial period marine isotope stage mis 5 5 assuming a span of possible paleo sea levels at the time of the last interglacial period yields long term tectonic uplift rates of 0 02 0 11 m ka supporting the hypothesis that the tectonic uplift rate is low nevertheless on the eastern and southern coasts of cuba east and west of guantanamo bay there are flights of multiple marine terraces at higher elevations that could record a higher rate of uplift implying that guantanamo bay may be anomalous southern cuba is considered to have experienced a measurable but modest effect from glacial isostatic adjustment gia processes thus with a low uplift rate guantanamo bay should show no evidence of emergent marine terraces dating to the 100 ka mis 5 3 or 80 ka mis 5 1 sea stands and results of the present study support this

submerged late pleistocene reefs on the tectonically stable s e florida margin high precision geochronology stratigraphy resolution of substage 5a sea level elevation and orbital forcing abstract a well preserved submerged in situ fossil reef tract lies offshore of the southeast florida carbonate margin in the florida keys cores in two transects enabled reconstruction of reef stratigraphy and paleoenvironments paleo water depths and paleo sea levels because florida is tectonically stable the elevation data required correction only for the known minor subsidence rate twenty eight pristine aragonitic corals were dated via high precision tims u series methods to produce a comprehensive late pleistocene and early holocene geochronology the pleistocene section of the fossil reef includes a thick section of substage 5a reef growth recorded from 15 to 11 m msl spanning an age range of 86 2 80 9 ka paleoenvironmental reconstruction local water quality constraints and elevations of concurrent bahamian speleothem growth combine to limit sea level to 9 0 m msl at 83 ka this coincides unlagged with the 82 ka 65 n july insolation peak the absence of any lag suggests that the earlier peak in obliquity at 92 ka also controls paleoclimate and sea level a below present sea level estimate for substage 5a from the florida fossil reef data coincides more closely with uplift corrected reef data estimates of 15 to 13 m msl from tectonic margins such as barbados and haiti than with higher than present sea levels derived from detrital corals from bermuda and the u s atlantic coastal plain the best tims dates on corals and speleothem constraining sea level combine to produce a new regional sea level curve for the atlantic caribbean region for late isotope stage 5 and early stage 4

sea level at the last glacial maximum evidence from northwestern australia to constrain ice volumes for oxygen isotope stage 2 new sea level information from the bonaparte gulf in northwestern australia is used to constrain the magnitude and rates of change of ice volumes during the last glacial maximum lgm the region is tectonically stable and far from the former ice covered regions the glacio hydro isostatic adjustment of the coast is therefore relatively small and the corrections for this evect are not sensitive to details of the rebound model microfossil analysis and ams radiocarbon dating of 11 gravity cores taken across the shelf and bonaparte gulf demonstrate that 1 the lgm sea levels were locally at 125 4 m 2 the lgm terminated abruptly at 19 000 cal yr bp with a rapid rise in sea level of about 15 m over the next 500 years and 3 the onset of the minimum sea levels occurred before 22 000 cal yr bp when corrected for the glacio hydro isostatic evects the increase of lgm ice volumes over the present day ice volume is 52 5 106 km3 the termination of the lgm is marked by a rapid ice discharge of 5 2 106 km3 2001 elsevier science b v all rights reserved

sea level change glacial rebound and mantle viscosity fornorthern europe northwestern europe remains a key region for testing models of glacial isostasy because of the good geological record of crustal response to the glacial unloading since the time of the last glacial maximum models for this rebound and associated sea level change require a detailed knowledge of the ice sheet geometry including the ice thickness through time existing ice sheet reconstructions are strongly model dependent and inversions of sea level data for the mantle response may be a function of the model assumptions thus inverse solutions for the sea level data are sought that include both ice and earth model parameters as unknowns sea level data from fennoscandia the north sea the british isles and the atlantic and english channel coasts have been evaluated and incorporated into the solutions the starting ice sheet for fennoscandia is based on a reconstruction of a model by denton hughes 1981 that is characterized by quasi parabolic cross sections and symmetry about the load centre both global northwestern europe as a whole and regional subsets of the data solutions have been made for earth model parameters and ice height scaling parameters the key results are as follows 1 the response of the upper mantle to the changing ice and water loads is spatially relatively homogenous across scandinavia the north sea and the british isles 2 this response can be adequately modelled by an effective elastic lithosphere of thickness 65 85 km and by an effective upper mantle viscosity from the base of the lithosphere to the 670 km depth seismic discontinuity of about 3 4 1020 pa s the effective lower mantle viscosity is at least an order of magnitude greater 3 the ice thickness over scandinavia at the time of maximum glaciation was only about 2000 m much less than the 3400 m assumed in the denton hughes model 4 the ice profiles are asymmetric about the centre of the ice sheet with those over the western part being consistent with quasi parabolic functions whereas the ice heights over the eastern and southern regions increase much more slowly with distance inwards from the ice margin

luminescence dating of interglacial coastal depositional systems recent developments and future avenues of research abstract luminescence dating offers new opportunities to explore the evolution of quaternary marine coastal facies and landforms this review highlights the main advances in luminescence geochronology of interglacial coastal sediments through the analysis of 547 luminescence ages most of which were published during the last decade the majority of these reported luminescence investigations have been carried out along passive margin coasts since the turn of the century the discovery of a normalization procedure known as single aliquot regeneration sar has drastically reduced data scatter and improved precision with the consequence that quartz sar optically stimulated luminescence osl has become the dating protocol of choice for the last interglacial lig period a more complex technique known as thermally transferred osl tt osl is presumably proposed for dating older interglacials of the mid pleistocene and beyond feldspar luminescence is increasingly being applied to dating pleistocene sea level high stands due to a much higher dose saturation level than quartz osl the use of feldspar irsl infrared stimulated luminescence is limited by the occurrence of variable but ubiquitous anomalous fading af following the advent of af correction methods several middle pleistocene sites have been amenable to dating albeit with significant related uncertainties recently new protocols involving the measurement of post ir irsl at elevated temperatures have yielded relatively coherent ages for interglacial sediments up to ca 300 ka quartz osl tt osl af corrected irsl and post ir irsl ages are generally correlated with periods of sea level high stands a few ages are reported from the early and middle part of the middle pleistocene as mis11 9 and more commonly mis7 high stands are documented in strongly uplifting active margin coasts however by far the most obvious age peak corresponds to the end of the lig the mis5e shoreline is probably the most studied and luminescence dated coastal feature of all as the chronology of the sea level markers is crucial to assess global eustatic sea level variations through the course of the last interglacial nevertheless the observed abundance of young 100 120 ka luminescence ages for presumed mis5e sediments may underline methodological issues and or reflect the higher preservation potential of late regressive sequences on the other hand the occurrence of geographically distant reports of mis5a high stand might reflect a true eustatic origin for this event age analysis supports the impression of general reliability of luminescence for the timing of former sea level high stands there is a clear need to address issues in dose rate variability in the phenomenology of fading in feldspar and in the behaviour of luminescence growth with dose both in laboratory and natural conditions these could be addressed and properly evaluated by dating different minerals as multiple or single grains with consequent variable internal dose rates more robust practices in the application of luminescence dating techniques could eventually constrain the age uncertainties to no better than 2 3 therefore the strength of luminescence as a dating tool is more in terms of its extended age range and the ubiquity of datable material

pleistocene sea levels from raised coral reefs of haiti the elevations and ages of a sequence of three uplifted pleistocene coral reefs on the northwest peninsula of haiti have been determined with the assignment of a sea level of 6 meters relative to the present day at 130 000 years before present and constant uplift of the reefs the data indicate that sea level stood 10 and 13 meters at 108 000 and 81 000 years before present respectively these results are in substantial agreement with those reported for barbados and new guinea and support the hypothesis of constant uplift for each area sea level data from raised reefs indicate that the interglacial marine oxygen isotope oscillations during oxygen isotope stage 5 are a result of 30 percent ice volume effects and 70 percent temperature effects

k ar evidence from illitic clays of a late devonian age for the 120 km diameter woodleigh impact structure southern carnarvon basin western australia abstract woodleigh is a recently discovered impact structure with a diameter of 120 km and thereby represents the third largest proven phanerozoic impact structure known after morocweng and chicxulub k ar isotopic studies of fine grained authigenic illitic clay minerals

variability in the uranium isotopic composition of the oceans over glacial interglacial timescales uranium series mass spectrometric analyses of corals from the uplifted last glacial terraces at huon peninsula papua new guinea that grew from 50 000 years ago to 30 000 years ago show systematically low values of 234u 238u at the time of coral growth compared with modern corals when combined with coral data from other studies a systematic trend emerges indicating shifts in the 234u 238u ratio at times of major glacial interglacial transitions that involve large variations in sea levels from last glacial to holocene the rate of change in 234u is approximately 1 per thousand years the variations in the u budget of the oceans appear to be due to accumulation of excess 234u in near shore areas in anoxic and suboxic sediments in salt marshes and mangroves in estuaries and in continental margins during periods of warm climate and high sea levels these near shore areas are exposed during periods of low sea level resulting in rapid oxidation of u into highly soluble phases the subsequent release of 234u enriched uranium into the oceans occurs over a sustained period in step with rising sea levels

a global compilation of coral sea level benchmarks implications and new challenges i present a quality controlled compilation of sea level data from u th dated corals encompassing 30 studies of 13 locations around the world the compilation contains relative sea level rsl data from each location based on both conventional and open system u th ages i have applied a commonly used age quality control criterion based on the initial 234u 238u activity ratios of corals in order to select reliable ages and to reconstruct sea level histories for the last 150 000 yr this analysis reveals scatter of rsl estimates among coeval coral benchmarks both within individual locations and between locations particularly during marine isotope stage mis 5a and the glacial inception following the last interglacial the character of data scatter during these time intervals imply that uncertainties still exist regarding tectonics glacio isostacy u series dating and or coral position to elucidate robust underlying patterns with confidence limits i performed a monte carlo style statistical analysis of the compiled coral data considering appropriate age and sea level uncertainties by its nature such an analysis has the tendency to smooth obscure millennial scale and finer details that may be important in individual datasets and favour the major underlying patterns that are supported by all datasets this statistical analysis is thus functional to illustrate major trends that are statistically robust what we know trends that are suggested but still are supported by few data what we might know subject to addition of more supporting data and improved corrections and which patterns data are clear outliers unlikely to be realistic given the rest of the global data and possibly needing further adjustments prior to the last glacial maximum and with the possible exception of the 130 120 ka period available coral data generally have insufficient temporal resolution and unexplained scatter which hinders identification of a well defined pattern with usefully narrow confidence limits this analysis thus provides a framework that objectively identifies critical targets for new data collection improved corrections and integration of coral data with independent stratigraphically continuous methods of sea level reconstruction

estimating the sea level highstand during the last interglacial a probabilistic massive ensemble approach essential to understanding sea level change and its causes during the last interglacial is the quantification of uncertainties in order to estimate the uncertainties we develop a statistical framework for the comparison of paleao climatic sea level index points and gia model predictions for the investigation of uncertainties as well as to generate better model predictions we implement a massive ensemble approach by applying a data assimilation scheme based on particle filter methods the different runs are distinguished through varying ice sheet reconstructions based on oxygen isotope curves and different parameter selections within the gia model this framework has several advantages over earlier work such as the ability to examine either the contribution of individual observations to the results or the probability of specific input parameters this exploration of input parameters and data leads to a larger range of estimates than previously published work we illustrate how the assumptions that enter into the statistical analysis such as the existence of outliers in the observational database or the initial ice volume history can introduce large variations to the estimate of the maximum highstand thus caution is required to avoid over interpreting results we conclude that there are reasonable doubts whether the datasets previously used in statistical analyses are able to tightly constrain the value of maximum highstand during the last interglacial lig

geologically and geomorphologically constrained numerical model of laurentide ice sheet inception and build up abstract the locations shapes and masses of evolving ice sheets during interglacial to glacial transitions remain elusive but need to be clarified for identification of the climatic feedbacks that amplified low amplitude insolation changes to become the major global climatic shift of the last glacial maximum the best way to explore probable spatial patterns of ice sheet inception and build up is through ice sheet modelling and validating model output against geomorphological and geological data we have modelled the 120 55 kyr bp evolution of the laurentide ice sheet focusing on the locations outline flow patterns and basal thermal regimes of its precursor ice centres for this we employed a time dependent mass balance driven finite element model forced with grip ice core oxygen isotope values calibrated to temperature the model achieves a good fit to relict ice flow systems in keewatin the interior plains and the hudson bay lowland thus our model indicates that the first coherent ice centre in north america was situated over baffin island and the melville and boothia peninsulas and expanded onto mainland canada at 90 75 kyr bp a previously unknown 200 km long moraine zone near the thlewiaza river keewatin may demarcate the marginal position of this early central arctic ice sheet cordilleran and keewatin ice merged and the hudson bay lowland was inundated from the east from quebec by 65 kyr bp

whole rock aminostratigraphy and quaternary sea level history of the bahamas abstract the surficial geology of the tectonically stable bahamian archipelago preserves one of the most complete records of middle to late quaternary sea level highstand cycles in the world however with the exception of deposits from marine isotope substage mis 5e fossil corals for radiometric dating of this rich stratigraphic sequence are rare this study utilizes the previously published independent lithostratigraphic framework as a testing ground for amino acid racemization in whole rock limestone samples at least six limestone soil couplets provide a relative age sequence of events that encompass as many interglacial glacial cycles d alloisoleucine l isoleucine data fall into six clusters or aminozones on the basis of independent dating and the inferred correlation with global mis the ages of several aminozones are known while the ages of others are calculated from calibrated amino acid geochronology this study demonstrates the utility of the whole rock aminostratigraphy method for dating and correlating widespread emergent marine deposits constitutes the first regional geochronological framework for the bahamas and highlights major sea level events over the past half million years

precise chronology of the last interglacial period 234u 230th data from fossil coral reefs in the bahamas a detailed study of 238 u 234 u 230 th ages was made for different coral species from two bahamian reefs to determine the time scale of the sea level high during the last interglacial period using recently developed mass spectrometric techniques for the measurement of u and th isotopes thirty seven coral samples were analyzed in replicate typical errors at 125 ky are 1 5 ky 2 and 3 ky time intervals appear to be well resolved this high precision permits detailed chronologic study with time resolution adequate to define stages of the reef s history these data demonstrate that the time between transgression and regression of the ocean in the last interglacial was about 12 ky after which sea level fell rapidly at more than 2 m ky the high sea level stand began possibly by 132 ky and certainly by 129 ky ago when sea level reached 6 m above present mean low sea level high sea level was sustained until 120 ky and then fell rapidly this time period covers the milankovitch insolation peak at 65 n but is not sharply defined and the sea level high lasted from about 4 ky before the insolation peak to 8 ky after it we find no evidence for a double peak of sea level rise in the last interglacial episode that is high stands at both 125 and 142 ky there appears to be some discrepancy between this precise chronology for a coral reef on a tectonically stable platform and the chronology assigned to deep sea sediments the present results show that the duration of the last interglacial led to a 12 ky period of high sea level stand which is much longer than the insolation peak the study area consists of two sizeable bank barrier coral reefs of sangamon age that crop out along the coast northwest of cockburn town on san salvador island and at devil s point on great inagua island the initial stage of reef development is not revealed at either site but the main parts of both reefs are well preserved at cockburn town the beginning of the reef was marked by colonization of acropora palmata on hardground areas and possibly other corals at 132 ky ago patch reefs at the southeastern flank of the developing reef were growing by 129 to 126 ky ago by 126 to 123 ky ago the crest of the reef was formed by the frame building coral a palmata and associated patch reefs flourished along its flanks a palmata coral heads grew upward to a mean low sea level 6 m above the present one the reef began to decline as sea level dropped at about 123 to 120 ky ago near two measured profiles at devil s point the top of a rubblestone dominated by a cervicornis and patch reef corals preserved in growth position have been beveled off and represent an ancient wave cut surface 230 th ages on corals below and above this surface indicate that it was cut at about 125 1 ky ago

late quaternary deformation history of the volcanic edifice of panarea aeolian arc italy a series of raised palaeoshorelines is documented along the emergent coastal slopes of panarea and surrounding islets at elevations of 115 palaeoshoreline ia and 100 m a s l ib 62 5 m ii 35 m iii 12 m iv 10 12 va and 5 m vb according to stratigraphic constraints and cross cutting relationships these palaeoshorelines are correlated with discrete high sea level stillstands during marine oxygen isotope stages mis 5e 5c 5a and 3 coastal elevation changes suggest the occurrence of a long term sustained uplift trend of the volcanic edifice since the last interglacial last 124 ka the uplift rates are not constant but display a progressive deceleration from maximum values of 1 5 1 58 m ka in the period between 124 and 100 ka down to the lowest values of 0 66 0 69 m ka which tend to be constant starting from 81 ka bp the long term deformation pattern of panarea suggests that a transitory volcano related component of uplift interplayed with the regional tectonic component affecting the sub volcanic basement which has undergone a persistent and widespread uplift since the mid pleistocene the volcano related component of uplift prevailing between 124 and 100 81 ka is interpreted as the result of visco elastic deformation mechanisms which characterize the progressive re equilibration of the shallow magmatic system following the incoming quiescence of the volcanic edifice the long term uplift values at panarea are higher than in the main portion of the western central aeolian arc where a mean uplift rate of 0 34 m ka was estimated since the last interglacial last 124 ka such a pattern of deformation on a regional scale may be a response to active deformation processes connected with the southeastward rollback of the subducting ionian slab which is still active only in correspondence with the eastern sector of the aeolian arc including panarea in the short term a localized submergence trend has been documented at the nearby islet of basiluzzo for the last 2 000 years likely connected to neo tectonic movements along main ne sw trending faults

a revised morpho and chronostratigraphy of the late and middle pleistocene coral reef terraces on southern barbados west indies the barbados coral reef terraces are one of the few type localities worldwide that provide insights into interglacial sea level change during the late and middle pleistocene several sea level estimates have been established since the late 1960s and each has contributed to the barbados model of sea level change this paper presents new morpho and chonostratigraphic data from the barbados coral reef terraces developed over the last 12 years the work is based on significant advances in electron spin resonance esr dating of fossil coral air photo interpretation and a greatly improved geomorphic map of preserved fossil beach formations and reef terraces above present sea level the need for a revision of past published morpho and chronostratigraphies is best demonstrated on the southern part of the island the morpho and chronostratigraphic sequence in this region is both more complex and diverse than has been assumed so far the revised morphostratigraphy presented here includes a differentiation of coral reef terraces wave cut platforms and other erosive features such as notches and cliffs our study of these geomorphic features combined with new numeric dating results esr u th enable a revised estimate of the spatial and temporal variation in tectonic uplift rate within south barbados these new rates are an essential requirement for more precise glacio eustatic sea level reconstructions during the late and middle pleistocene from this region

initiation and development of the laurentide and cordilleran ice sheets following the last interglaciation abstract fossil records from sites overridden by or adjacent to the laurentide ice sheet indicate that the climate of the last interglaciation oxygen isotope substage 5e ca 130 116 ka was warmer than today following the last interglaciation the laurentide ice sheet first developed during stage 5 over keewatin quebec and baffin island along its northern margin the ice sheet reached its maximum extent of the last glaciation during stage 5 the ice sheet advanced across baffin island onto the continental shelf early during stage 5 5d whereas the advance into the western canadian arctic occurred late during stage 5 5b the ice sheet also may have advanced into the st lawrence lowland during substage 5b although this event may be younger stage 4 the hudson bay lowland became ice free during substage 5a retreat of the ice sheet on baffin island occurred during late stage 5 probably substage 5a the exact timing of retreat from the western canadian arctic is unknown but it occurred before 48 ka the southern sector including the st lawrence lowland was ice free during late stage 5 the hudson bay lowland may have remained ice free through stage 4 and much of stage 3 because of conflicting chronologies however it is more likely that this area was glaciated throughout stage 3 and perhaps stage 4 nevertheless the data demonstrate that the lowland was ice free during part of the last glaciation an independent ice cap developed over the appalachian uplands and advanced across nova scotia during stage 4 perhaps as far as the edge of the continental shelf the ice cap remained active over nova scotia as a setellite to the laurentide ice sheet throughout the remainder of the last glaciation the ice sheet advanced into the st lawrence lowland during stage 4 and subsequently overwhelmed the local ice cap in the appalachian uplands advancing perhaps into northern new england but not farther south the lowland remained covered by the ice sheet until late stage 2 the ice sheet may also have advanced into the lake ontario basin during stage 4 the position of the northern margin of the laurentide ice sheet during stage 4 is not known but it remained an unknown distance behind its maximum position reached during stage 5 cores from baffin bay indicate a substantial decrease in high latitude glaciation during stage 4 following retreat the keewatin sector of the ice sheet may have remained over much of northwestern canada as a quasi stable ice mass until it readvanced during stage 2 similarly the baffin island sector of the ice sheet may have remained largely intact the southern margin of the ice sheet may have advanced into the lake ontario basin and upper mississippi valley during the middle of stage 3 ca 50 ka reaching its maximum extent of the last glaciation during stage 2 ca 18 21 ka advance of the northern margin was younger ca 8 13 ka than that of the southern margin this advance was less extensive than the penultimate advance stage 5 paleoenvironmental records indicate that the last interglaciation in areas covered by and near the cordilleran ice sheet was as warm as or warmer than present the cordilleran ice sheet appears to have developed during stage 5 or 4 at that time it advanced over southern british columbia and into the northern puget lowland there is no record of this event in northern areas that were later covered by the ice sheet the ice sheet disappeared before 59 ka at the beginning of a lengthy nonglacial interval paleoenvironmental records indicate that climate was similar to the present during part of this interval the ice sheet was absent and glaciers probably were confined to mountain areas throughout stage 3 climatic deterioration marking the end of this nonglacial interval may have begun as early as 29 ka by 14 15 ka the ice sheet had achieved its maximum extent of the last glaciation because there are few suitable dating methods capable of resolving events beyond the radiocarbon limit and because sites that preserve a record of events from the last glaciation are spatially restricted we consider this synthesis as tentative and subject to significant revision as dating methods improve nevertheless this perspective of the north american ice sheets through the last glaciation demonstrates their complex and dynamic behavior and attendant rapid fluctuations in ice volume

glacial isostatic adjustment and the radial viscosity profile from inverse modeling 1 a formal inverse procedure is used to infer radial mantle viscosity profiles from several observations related to the glacial isostatic adjustment process the data sets consist of late pleistocene and holocene sea level data from scandinavia the barents sea central europe canada and the far field as well as observations of changes in the earth s rotation and gravitational field and present day uplift and gravity changes in scandinavia inferences of mantle viscosity are robust against assumptions such as the a priori viscosity model and model discretization however the quality of ice sheet reconstruction remains crucial for the inverse inference the importance to discuss regional mantle viscosity models in view of the lateral variability in mantle properties has been evident our inference suggests a two order of magnitude increase of mantle viscosity with depth and volume averaged upper and lower mantle viscosities around 7 1020 and 2 1022 pa s respectively mantle viscosity does not need to increase sharply across the 660 km seismic discontinuity the viscosity profiles suggested are also able to reconcile the large scale geoid anomaly related to mantle convection

sea level history of the past two interglacial periods new evidence from u series dating of reef corals from south florida abstract as a future warm climate analog much attention has been directed to studies of the last interglacial period or marine isotope substage mis 5 5 which occurred 120 000 years ago nevertheless there are still uncertainties with respect to its duration warmth and magnitude of sea level rise here we present new data from tectonically stable peninsular florida and the florida keys that provide estimates of the timing and magnitude of sea level rise during the last interglacial period the last interglacial high sea stand in south florida is recorded by the key largo limestone a fossil reef complex and the miami limestone an oolitic marine sediment thirty five new high precision uranium series ages of fossil corals from the key largo limestone indicate that sea level was significantly above present for at least 9000 years during the last interglacial period and possibly longer ooids from the miami limestone show open system histories with respect to u series dating but show a clear linear trend toward an age of 120 ka correlating this unit with the last interglacial corals of the key largo limestone older fossil reefs at three localities in the florida keys have ages of 200 ka and probably correlate to mis 7 these reefs imply sea level near or slightly above present during the penultimate interglacial period elevation measurements of both the key largo limestone and the miami limestone indicate that local relative sea level was at least 6 6 m and possibly as much as 8 3 m higher than present during the last interglacial period

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

coupled uranium isotope and sea level variations in the oceans abstract globally rivers supply uranium to the oceans with excess 234 u relative to secular equilibrium and 234 u taken up by corals can be used for dating in addition the 234 u abundance in sea water at the time the coral was growing can be measured independently the veracity of u series ages used in determining past sea level variations is dependent on selecting pristine corals free from diagenetic alteration a quantitative test for alteration assumes invariant 234 u abundances in the oceans for at least the past half a million years and results from samples outside of a narrow range in modern ocean 234 u abundance are excluded from data sets here we have used previously published data to show that 234 u in the oceans appears to be variable and directly related to changes in sea level not only over long glacial interglacial timescales but also at very short centennial timescales most of the previously discarded data can be used to provide valuable additional sea level information the process permits a unique insight into the interplay between sources and sinks of uranium in the oceans mediated by sea level changes at rates far faster than previously thought possible similar rapid sea level forcing of other trace element abundances in the oceans is likely

mass spectrometric 234u 230th ages from the key largo formation florida keys united states constraints on diagenetic age disturbance new mass spectrometric 234 u 230 th ages for the key largo formation confirm earlier less precise alpha counting measurements that place the unit within marine oxygen isotope stage 5 ages derived from the petrographically freshest samples 99 aragonite of this study range from 125 to 138 ka despite careful sample selection and preparation the initial 234 u 238 u activity ratios denoted 234 u 238 u t range from 1 163 to 1 176 and so are all significantly higher than modern day or inferred last interglacial seawater this result indicates open system behavior of u series nuclides as has been observed in many other pleistocene coral samples and casts doubt on the accuracy of our age determinations we have used our samples to investigate the processes and magnitudes of age perturbations repeats of the same sample dissolution analytical reproducibility are within measured uncertainties which are generally less than 1 k y in contrast different parts of the same coral similarly screened for alteration can show age differences of as much as 3 k y evidence from this study and others suggests that alteration generally increases 234 u 230 th ages we were able to determine by using field relationships that the differences in 234 u 230 th ages of samples lying on either side of an erosion feature are at least 5 k y in error the stratigraphically younger corals above the erosion surface have 234 u 230 th ages that are at least 5 k y too old notably these apparently more perturbed samples have lower 234 u 238 u t ratios than the underlying corals this observation emphasizes that although 234 u 238 u t is a sensitive indicator of open system behavior the 234 u 238 u t ratio does not provide a simple index of the magnitude of age disturbance diagenetic additions of both 234 u and 230 th to corals seem necessary to explain both elevated ages and 234 u 238 u t ratios we argue that these additions result from redistribution of nuclides during meteoric alteration of the reef in the first 40 k y after formation variations in the amount of 230 th added relative to 234 u can be used to model the spread of ages at similar 234 u 238 u ratios although variable amounts of recent u loss may also have been important the youngest age of this study 125 ka just below an erosion surface is compatible with the ages of similar features in the southern bahamas we suggest that 125 ka is the maximum age of a short lived sea level lowstand within the last interglacial 5e highstand

rapid and widespread response of the lower mississippi river to eustatic forcing during the last glacial interglacial cycle discussion shen et al 2012 1 address critical issues related to fluctuating late pleistocene sea levels associated climate phases and their likely impact during erosion and aggradation episodes in the lower and middle mississippi river valley nineteen new pleistocene optically stimulated luminescence

differences between the last two glacial maxima and implications for ice sheet δ18o and sea level reconstructions studies of past glacial cycles yield critical information about climate and sea level ice volume variability including the sensitivity of climate to radiative change and impacts of crustal rebound on sea level reconstructions for past interglacials here we identify significant differences between the last and penultimate glacial maxima lgm and pgm in terms of global volume and distribution of land ice despite similar temperatures and radiative forcing our analysis challenges conventional views of relationships between global ice volume sea level seawater oxygen isotope values and deep sea temperature and supports the potential presence of large floating arctic ice shelves during the pgm the existence of different glacial modes calls for focussed research on the complex processes behind ice age development we present a glacioisostatic assessment to demonstrate how a different pgm ice sheet configuration might affect sea level estimates for the last interglacial results suggest that this may alter existing last interglacial sea level estimates which often use an lgm like ice configuration by several metres likely upward

uranium series coral ages from the us atlantic coastal plain the 80 ka problem revisited abstract uranium series coral ages for emergent units from the passive continental margin us atlantic coastal plain acp suggest sea level above present levels at the end of marine oxygen isotope stage mis 5 contradicting age elevation relations based on marine isotopic or coral reef models of ice equivalent sea level we have reexamined this problem by obtaining high precision 230th 238u and 231pa 235u thermal ionization mass spectrometric ages for recently collected and carefully cleaned acp corals many in situ we recognize samples that show no evidence for diagenesis on the basis of uranium isotopic composition and age concordance combining new and earlier data among those ages close to or within the age range of mis 5 over 85 cluster between 65 and 85 ka bp of the corals that we have analyzed those that show the least evidence for diagenesis on the basis of uranium isotopic composition and age concordance have ages between 80 and 85 ka bp consistent with a mis 5a correlation the units from which these samples have been collected are all emergent and have elevations within 3 5 m of those few units where early stage 5 125 000 ka bp coral ages have been obtained the acp appears to record an unusual history of relative sea level throughout mis 5 a history that is also apparent in the dated coral record for bermuda we speculate that this history is related to the regional near to intermediate field effects of ancestral laurentide ice sheets on last interglacial shorelines of the western north atlantic

seismic stratigraphic evidence for a submerged middle wisconsin barrier implications for sea level history high resolution seismic reflection data from the inner shelf and coastal zones of central new jersey document the presence of two depositional sequences seismic facies analysis of the lower sequence indicates the presence of a submerged barrier island complex 20 m below present sea level and 0 2 to 1 7 km seaward of the modern coastline vibracore data from within the study area and correlation to an extensive seismic data set that extends farther offshore identify this submerged barrier as the maximum highstand shoreface associated with the middle wisconsin oxygen isotope stage 3 interstade the results indicate that sea level was well below its present day level during the middle wisconsin and not at or above the present level as has been frequently proposed

uplift rates of marine terraces as a constraint on fault propagation fold kinematics examples from the hawkswood and kate anticlines north canterbury new zealand abstract marine terraces on growing fault propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates providing a means to distinguish among otherwise non unique kinematic model solutions here we investigate this relationship at two locations in north canterbury new zealand the kate anticline and haumuri bluff at the northern end of the hawkswood anticline at both locations we calculate uplift rates of previously dated marine terraces using dgps surveys to estimate terrace inner edge elevations we then use markov chain monte carlo methods to fit fault propagation fold kinematic models to structural geologic data and we incorporate marine terrace uplift into the models as an additional constraint at haumuri bluff we find that marine terraces when restored to originally horizontal surfaces can help to eliminate certain trishear models that would fit the geologic data alone at kate anticline we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel fault propagation fold kink band model finally we use our model results to compute new estimates for fault slip rates 1 2 m ka at kate anticline and 1 4 m ka at haumuri bluff and ages of the folds 1 ma which are consistent with previous estimates for the onset of folding in this region these results are consistent with previous work on the age of onset of folding in this region provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non unique solutions

the influence of sediment isostatic adjustment on sea level change and land motion along the u s gulf coast sea level rise presents a hazard for coastal populations and the mississippi delta md is a region particularly at risk due to the high rates of land subsidence we apply a gravitationally self consistent model of glacial and sediment isostatic adjustment sia along with a realistic sediment load reconstruction in this region for the first time to determine isostatic contributions to relative sea level rsl and land motion we determine optimal model parameters earth rheology and ice history using a new high quality compaction free sea level indicator database using the optimal model parameters we show that sia can lower predicted rsl in the md area by several meters over the holocene and so should be taken into account when modeling these data we compare modeled contemporary rates of vertical land motion with those inferred using gps this comparison indicates that isostatic processes can explain the majority of the observed vertical land motion north of latitude 30 7 n where subsidence rates average about 1 mm yr however subsidence south of this latitude shows large data model discrepancies of greater than 3 mm yr indicating the importance of nonisostatic processes this discrepancy extends to contemporary rsl change where we find that the sia contribution in the delta is on the order of 10 1 mm yr we provide estimates of the isostatic contributions to 20th and 21st century sea level rates at gulf coast permanent service for mean sea level tide gauge locations as well as vertical and horizontal land motion at gps station locations near the md

u series and amino acid racemization geochronology of bermuda implications for eustatic sea level fluctuation over the past 250 000 years abstract bermuda is a stable mid oceanic carbonate platform for which a particularly complete record of late pleistocene eustatic sea level fluctuation has been reconstructed from a detailed study of geological field relationships combined with an extensive programme of u series and amino acid racemization geochronology only twice in the past 250 000 yr has sea level in bermuda been above its present level once at approximately 200 k y when it stood at about 2 m and most recently at 125 4 k y when it stood at 5 1 m these times of interglacial high sea level are characterized by the development of patch reefs and marine calcarenites at elevations above present sea level episodes of lower sea stand onto the bermuda platform at elevations higher than 20 m are observed within the two interglacial periods and are characterized by the deposition of eolianites by contrast glacial periods are times of residual soil formation and deposition of speleothems in caves at elevations below present sea level excellent correlation is observed between the bermuda glacio eustatic sea level record and other marine and terrestrial paleoclimate records

uranium series dating of fossil corals from marine sediments of southeastern united states atlantic coastal plain extensive low lying marine deposits border the southeastern united states atlantic coastal plain some units are fossiliferous and contain corals as isolated fragments in sediments of a detrital character these corals are subject to alteration processes such that suites of related samples must be examined to determine the suitability of these coral samples for reliable uranium series dating with the exception of those from one location most samples appear to have remained closed systems with respect to the isotopes of uranium and thorium throughout their geologic history extraneous 230th has been detected in some of the corals due to incorporation of some detrital materials into their skeletons for these samples different methods are applied to correct for the initial 230th contamination continued sampling and analyses have resulted in 55 individual uranium thorium determinations the average 230th ages of samples from the norfolk formation and from later and earlier deposited sediments of the wando formation are 71 000 87 000 and 129 000 yr and they appear to correlate with oxygen isotope substages 5a 5c and 5e respectively the average 230th age of samples from beds of the rappahannock river ponzer and ten mile hill localities is 212 000 yr and they correlate with oxygen isotope stage 7 the sediment of the canepatch formation is 460 000 yr old and it is tentatively correlated with oxygen isotope stage 11 there is general agreement between uranium series and uranium trend dates and between the quantitative trends of the amino acid data and uranium series dates the amino acid values however ure unacceptably high in at least two groups of samples those from localities near charleston south carolina and from central virginia

ice volume and sea level during the last interglacial during the last interglacial period 125 000 years ago sea level was at least several meters higher than at present with substantial variability observed for peak sea level at geographically diverse sites speculation that the west antarctic ice sheet collapsed during the last interglacial period has drawn particular interest to understanding climate and ice sheet dynamics during this time interval we provide an internally consistent database of coral u th ages to assess last interglacial sea level observations in the context of isostatic modeling and stratigraphic evidence these data indicate that global eustatic sea level peaked 5 5 to 9 meters above present sea level requiring smaller ice sheets in both greenland and antarctica relative to today and indicating strong sea level sensitivity to small changes in radiative forcing

quaternary climates and sea levels of the u s atlantic coastal plain uranium series dating of corals from marine deposits of the u s atlantic coastal plain coupled with paleoclimatic reconstructions based on ostracode marine and pollen continent data document at least five relatively warm intervals during the last 500 000 years on the basis of multiple paleoenvironmental criteria we determined relative sea level positions during the warm intervals relative to present mean sea level were 7 5 meters at 188 000 years ago 7 5 1 5 meters at 120 000 years ago 6 5 3 5 meters at 94 000 years ago and 7 3 meters at 72 000 years ago the composite sea level chronology for the atlantic coastal plain is inconsistent with independent estimates of eustatic sea level positions during interglacial intervals of the last 200 000 years hydroisostatic adjustment from glacial interglacial sea level fluctuations lithospheric flexure and isostatic uplift from sediment unloading due to erosion provide possible mechanisms to account for the discrepancies alternatively current eustatic sea level estimates for the middle and late quaternary may require revision

reconstructed topography of southern new england prior to isostatic rebound with implications of total isostatic depression and relative sea level abstract topographic models of the late quaternary landscape prior to isostatic rebound aid interpretation of glacial lake water levels and geomorphic features as well as ice thickness mantle viscosity and lithospheric strength the well established limit of glacial marine inundation in central and northern new england provides a test of total isostatic depression relative sea levels reflecting differing magnitudes of isostatic rebound show that published values of isostatic depression in southern new england would inundate the landscape in southern new england with marine water south of the limit of late pleistocene marine inundation this suggests that isostatic depression at the terminal margin of the laurentide ice sheet lis was 50 m a first order estimate of ice thickness based on total isostatic depression and the observed uplift profile in southern new england supports the thin ice models in new england ice thickness ranged from 100 m at the southeastern margin of the lis to 1000 m at a point 300 km north of the terminal margin this regional model places constraints on continental ice sheet and geophysical models that should be considered in the future

cold climate slope deposits and landscape modifications of the mid atlantic coastal plain eastern usa abstract the effects of pleistocene cold climate geomorphology are distributed across the weathered and eroded mid atlantic coastal plain uplands from the wisconsinan terminal moraine south to tidewater virginia cold climate deposits and landscape modifications are superimposed on antecedent landscapes of old weathered neogene upland gravels and pleistocene marine terraces that had been built during warm periods and sea level highstands in new jersey sequences of surficial deposits define a long history of repeating climate change events to the south across the delmarva peninsula and southern maryland most antecedent topography has been obscured by late pleistocene surficial deposits these are spatially variable and are collectively described as a cold climate alloformation the cold climate alloformation includes time transgressive details of climate deterioration from at least marine isotope stage mis 4 through the end of mis 2 some deposits and landforms within the alloformation may be as young as the younger dryas southwards along the trend of the potomac river these deposits and their climatic affinities become diffused in virginia a continuum of erosion and surficial deposits appears to be the product of normal temperate climate forced processes the cold climate alloformation and more temperate deposits in virginia are being partly covered by holocene alluvium and bay mud

sea surface correction of high spatial resolution ikonos images to improve bottom mapping in near shore environments a significant number of high spatial resolution 4 m ikonos images acquired over shallow coastal environments present quasi stochastic sea surface effects that seriously compromise reconnaissance of bottom features this problem is common in wide field of view images where there is limited control on acquisition conditions other than cloud cover to eliminate most of these wave and glint patterns we use the near infrared band which exhibits maximum absorption and minimal water leaving radiance over clear waters to characterize the spatial distribution of relative glint intensity which is then scaled by absolute glint intensities in each of the visible bands the result is subtracted from the visible bands thus filtering out glint effects corrected visible bands clearly reveal seabed structural features obscured in the original data before and after correction classifications of an ikonos image of lee stocking island bahamas reveal an improvement of user s accuracies for critical benthic habitat classes such as coral dominated habitat 46 8 versus 60 5 or dense seagrass beds 31 7 versus 52 1 this technique offers potential to use previously discarded sections of high spatial resolution airborne or satellite images of optically shallow water for mapping substrate features

sea level history of past interglacial periods from uranium series dating of corals curacao leeward antilles islands curacao has reef terraces with the potential to provide sea level histories of interglacial periods ages of the hato upper unit of the lower terrace indicate that this reef dates to the last interglacial period marine isotope stage mis 5 5 on curacao this high sea stand lasted at least 8000 yr 126 to 118 ka elevations and age of this reef show that late quaternary uplift rates on curacao are low 0 026 0 054 m ka consistent with its tectonic setting ages of 200 ka for corals from the older cortalein unit of the lower terrace correlate this reef to mis 7 with paleo sea level estimates ranging from 3 3 m to 2 3 m the estimates are in agreement with those for mis 7 made from other localities and indicate that the penultimate interglacial period was a time of significant warmth on a par with the present interglacial period the 400 ka mis 11 middle terrace i on curacao dated by others may have formed from a paleo sea level of 8 3 to 10 0 m or less likely 17 m to 20 m the lower estimates are conservative compared to previous studies but still require major ice sheet loss from greenland and antarctica

ups and downs of the mississippi delta during the last glacial period when sea level was low meltwater discharge drove incision of the lower mississippi valley with valley filling and delta construction during holocene sea level rise isostatic modeling shows that sediment volumes removed and replaced were sufficient to induce uplift of 9 m along valley margins followed by subsidence of the same magnitude with effects dissipating only over distances of 100 150 km along the gulf of mexico coast recognition of cyclical uplift and subsidence refutes recent interpretations of delta stability and suggests that late holocene relative sea level curves from the delta region are instead a record of subsidence of the pre holocene depocenter more broadly incised valley cutting and filling is a common fluvial response to glacioeustasy and cyclical uplift and subsidence should be common to large alluvial deltaic systems elsewhere

sea level reversal during termination ii the termination of the penultimate glacial period tii shows both similarities and differences to the last termination ti both terminations show significant cold reversals in the postglacial warming trend ti consists of a continuously increasing sea level trend whereas tii may demonstrate a sea level reduction midway through the termination we present a new continuous sea level record for tii derived from red sea 18 o records that supports the existence of the tii sea level reversal the record gives an unprecedented look at the structure of the tii sea level reversal which consists of an early highstand lasting several millennia in duration followed by a 30 12 m to 40 12 m reduction in sea level and a stillstand of several millennia before the final sea level rise to the marine oxygen isotope stage mis 5e interglacial we suggest that there is a link between the sea level reversal and internal millennial scale variability in the climate system

quaternary depositional patterns and sea level fluctuations northeastern north carolina abstract a detailed record of late quaternary sea level oscillations is preserved within the upper 45 m of deposits along an eight km transect across croatan sound a drowned tributary of the roanoke albemarle drainage system northeastern north carolina drill hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early pleistocene deposits on interfluves lithologically similar marine deposits of different sequences occur stacked in vertical succession and separated by ravinement surfaces within the paleo drainage marine deposits are separated by fluvial and or estuarine sediments deposited during periods of lowered sea level foraminiferal and molluscan fossil assemblages indicate that marine facies were deposited in a shallow marine embayment with open connection to shelf waters each sequence modifies or truncates portions of the preceding sequence or sequences sequence boundaries are the product of a combination of fluvial estuarine and marine erosional processes stratigraphic and age analyses constrain the ages of sequences to late marine isotope stage mis 6 and younger 140 ka to present indicating multiple sea level oscillations during this interval elevations of highstand deposits associated with late mis 5 and mis 3 imply that sea level was either similar to present during those times or that the region may have been influenced by glacio isostatic uplift and subsidence

testing glacial isostatic adjustment models of last interglacial sea level history in the bahamas and bermuda abstract part of the spatial variation in the apparent sea level record of the last interglacial lig period is due to the diverse response of coastlines to glacial isostatic adjustment gia processes particularly where coastlines were close to the laurentide ice sheet during the past two glacial periods we tested modeled lig paleo sea levels on new providence island npi bahamas and bermuda by investigating emergent coral patch reefs and oolitic peloidal beach deposits corals with closed system histories collected from patch reefs on npi have ages of 128 118 ka and ooids peloids from beach ridges have closed system ages of 128 116 ka elevations of patch reefs indicate a lig paleo sea level of at least 7 m to 9 m above present beach ridge sediments indicate paleo sea levels of 5 m to 14 m assuming subsidence 7 m to 16 m above present during the lig some though not all of these measurements are in good agreement with gia models of paleo sea level that have been simulated for the bahamas on bermuda corals with closed system histories collected from marine deposits have ages of 126 114 ka although coral bearing marine deposits on bermuda lack the precise indication of paleo sea level provided by patch reefs and oolitic beach ridges these sediments nevertheless provide at least a first order estimate of paleo sea level paleo sea level records on bermuda are consistently lower 2 m to 7 m than what gia models simulate for the lig the reason for the reasonable agreement with models for the bahamas and poor agreement for bermuda is not understood but needs further investigation in light of the probability of a higher sea level in the near future

tectonic constraints on the late pleistocene holocene relative sea level change along the north eastern adriatic coast croatia abstract in spite of very favourable coastal features late pleistocene holocene relative sea level changes along the eastern adriatic coast are still not completely resolved mostly due to the intensive and complicated regional and local neotectonics we gathered current knowledge that generally presents the north adriatic area as subsiding one and proposed a reconstruction in new light of possible very slow local uplift average rate of 0 1 0 25 mm a for last 80 ka which is supported by well dated submerged speleothems and tectonic reconstruction in addition such a scenario supports also the formation of tidal notches that are common in the north adriatic region but not yet entirely understood however according to the latest mediterranean data on sea level during the marine isotope stage mis 5 1 being at 1 m 80 ka ago we do not dismiss the possibility of subsidence which would have been 0 18 0 23 mm a on average for the last 80 ka but notch formation under such condition would not have been realistic apparently the position of the north eastern adriatic coast on a convergence area requires extensive palaeoenvironmental studies including structural lithostratigraphical palaeontological archaeological and radiometric data and application of isostatic modelling

influence of glacial isostatic adjustment on river evolution along the u s mid atlantic coast abstract long term river evolution depends partly on crustal deformation which shapes the topography crossed by rivers on glacial timescales ice sheet growth and decay can produce crustal vertical motion of 10 mm yr resulting from the solid earth s adjustment to variations in ice and water loads comparable to tectonically driven rates in the most rapidly uplifting mountains on earth this process of glacial isostatic adjustment gia can influence river courses and drainage basins substantially particularly near former ice margins we explore the extent to which gia influenced the evolution of rivers along the united states east coast during the last glacial cycle we compute gravitationally self consistent gia responses that incorporate recent constraints on the laurentide ice sheet history through the last glacial build up phase and we connect the predicted variations in topography to abrupt changes in river dynamics recorded in the hudson delaware susquehanna and potomac rivers from 40 ka to present to the extent that increases in sediment transport capacity imply increases in river incision rate the gia driven changes in slope and drainage area are consistent with episodes of erosion and sedimentation observed in the hudson delaware and potomac rivers but inconsistent with the observed accelerated river incision in the susquehanna river at 30 14 ka these analyses add to a growing body of evidence showing that gia strongly influences river evolution over millennial timescales

paleotempestology evidence recorded by eolian deposition in the bohai sea coastal zone during the last interglacial period abstract reconstruction of the generation development and evolution of modern storms through paleotempestology is used to understand the regularity of storm activity and the relationship between storm activity and global climate change existing paleotempestology research in china is concentrated mainly on the low latitude sediments deposited since the holocene about 7000 a in this study we examine the storm deposits in the eolian sediments of the bohai sea coastal zone at middle latitudes choosing the miaodao stratigraphic section mds as the target area this area is located in the bohai sea strait and shows evidence of storms since the last interglacial period using an analysis of the grain size parameter element ratios and marine micropaleontology foraminifera fossils in the sediment during the last 130 ka that can be used in our paleotempestology research the results include three main findings 1 the marine micropaleontology foraminifer fossils appear in the eolian sediment of the mds and in combination with grain size parameter and element ratios of the sediments serve as evidence of the paleotempestology record on the bohai sea coastal zone 2 planktonic foraminifera fossils appear in the mds indicating that the yellow sea warm current affected the bohai sea during the last interglacial period and 3 storm activity in the marine isotope stage mis 5a has been recorded in the mds 15 times the findings of this study expand the paleotempestology record from 7000 a to 90 ka and serve as a reference for research for middle latitude storm activity

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

uranium series chronology and environmental applications of speleothems an increasing number of scientists recognize the value of speleothems1 as often extremely well preserved archives of information about past climate vegetation hydrology sea level nuclide migration water rock interaction landscape evolution tectonics and human action well constrained data are required to document past changes reconstruct past patterns and predict future responses of the earth system at a wide range of spatial and temporal scales speleothems are particularly useful in this regard because they can be found in many locations of the globe sampled at high resolution and reliably dated using high precision uranium series techniques speleothems are bodies of mineral material formed in caves as the result of chemical precipitation from groundwater flowing or dripping in a cave most speleothems are composed of calcite formed by slow degassing of co2 from supersaturated groundwater but aragonite and gypsum forms are also common particularly near cave entrances where evaporative effects are important a host of different speleothem types decorate the walls ceilings and floors of caves and their mineralogy and morphology is a function of fluid flow and chemistry of waters feeding a particular location as well as the ambient conditions temperature chemistry light in the air or water filled void subaerial forms include the familiar stalagmites stalactites draperies flowstones subaqueous forms include rimstone pools rafts mammillary calcite wall coatings and dog tooth spar for an extensive review of the types of speleothem that have been observed see hill and forti 1997 speleothems are used in a multitude of ways to explore past environmental conditions perhaps the most fundamental of which is their very presence or absence deposition of speleothems relies on sufficient water supply and soil co2 to enable dissolution and transport of reactants in the vadose zone to underlying caves in arid or glacial times conditions may not have been favorable for speleothem formation

maximum sea levels for the last glacial period from u series ages of submerged speleothems pleistocene sea levels reflect changes in the surface distribution of land sea and ice which in turn significantly influence the earth s climate1 the most complete record of sea levels for the last glacial cycle has come from raised coral reef terraces of the huon peninsula papua new guinea2 4 but interpretation of this record is hampered by relatively large age uncertainties and the possibility of variation in the rate of tectonic uplift subaerial speleothems stalagmites stalactites and flowstones from submerged caves in tetonically stable areas provide an alternative source of data5 8 as their growth stops when rising sea levels flood the caves previous studies of speleothems have been limited by dating precision5 6 and sample availability5 7 here we present high precision thermal ionization mass spectrometric 230th ages9 11 for a comprehensive suite of speleothem samples from the bahamas our results provide a record of maximum elevation of sea levels for the period from 80 to 10 kyr before the present for much of which sea levels are poorly known we also find that regional palaeoclimatic change can be an important factor in the termination of speleothem growth

speleothem evidence for mis 5c and 5a sea level above modern level at bermuda the history of sea level in regions impacted by glacio isostasy provides constraints on past ice sheet distribution and on the characteristics of deformation of the planet in response to loading the western north atlantic caribbean region and bermuda in particular is strongly affected by the glacial forebulge that forms as a result of the laurentide ice sheet present during glacial periods the timing of growth of speleothems at elevations close to sea level can provide records of minimum relative sea level rsl in this study we used u th dating to precisely date growth periods of speleothems from bermuda which were found close to modern day sea level results suggest that rsl at this location was above modern during mis5e mis5c and mis5a these data support controversial previous indications that bermudian rsl was significantly higher than rsl at other locations during mis 5c and mis 5a we confirm that it is possible to explain a wide range of mis5c a relative sea levels observed across the western north atlantic caribbean in glacial isostatic adjustment models but only with a limited range of mantle deformation constants this study demonstrates the particular power of bermuda as a gauge for response of the forebulge to glacial loading and demonstrates the potential for highstands at this location to be significantly higher than in other regions helping to explain the high sea levels observed for bermuda from earlier highstands

sea level change during mis 5a based on submerged speleothems from the eastern adriatic sea croatia abstract two stalagmites were collected from below sea level in u vode pit on the krk island eastern adriatic sea at elevations of 14 5 and 18 8 m they exhibit a growth history indicating a double high sea level stand during marine isotope stage mis 5a 87 77 ka thin layers of halite and gypsum were found to be associated with hiatuses in speleothem growth probably caused by seawater inundation during sea level highstands these mineral deposits are likely to have been precipitated during marine regression phases under evaporitic conditions we constrain the age of the speleothem growth below and above growth hiatuses and hence timing of possible marine incursions using multi collector inductively coupled plasma mass spectrometry mc icpms u th techniques age estimates indicate that during mis 5a relative sea level elevations were greater than 14 5 m from 87 to 82 ka and 18 8 m from 77 to 64 ka and constrained to be lower than 18 8 m from 93 to 90 ka 82 to 77 ka and 64 to 54 ka assuming no tectonic adjustment however present speleothem depths could indicate long term regional tectonics

rapid sea level fall and deep ocean temperature change since the last interglacial period we have dated huon peninsula papua new guinea and barbados corals that formed at times since the last interglacial period applying both 230 th and 231 pa dating techniques as a test of age accuracy we show that marine isotope stage mis 5e ended prior to 113 1 8 0 7 kyr when sea level was 319 m during mis 5b sea level was 357 m at 92 6 8 0 5 kyr having dropped about 40 m in approximately 10 kyr during the mis 5c 5b transition sea level then rose more than 40 m during the mis 5b 5a transition also in about 10 kyr mis 5a lasted until at least 76 2 8 0 4 kyr at a level of 324 m at that time combined with earlier data that places mis 4 sea level at 381 m at 70 8 kyr our late mis 5a data indicate that sea level fell almost 60 m in less than 6 kyr 10 6 m kyr during the mis 5 4 transition the magnitude of the drop is half that of the glacial interglacial amplitude and approximatelyequivalent to the volume of the present dayantarctic ice sheet during this interval the minimum average rate of net continental ice accumulation was 18 cm yr likely facilitated by efficient moisture transport from lower latitudes at three specific times 60 6 8 0 3 50 8 8 0 3 and 36 8 0 2 kyr during mis 3 sea level was between 385 and 374 m sea level then dropped to 3107 m at 23 7 8 0 1 kyr early in mis 2 before dropping further to last glacial maximum lgm values and then rising to present values during the last deglaciation times of rapid sea level drop correspond to times of high winter insolation at low northern latitudes and high winter latitudinal gradients in northern hemisphere insolation supporting the idea that these factors mayhave resulted in high water vapor pressure in moisture sources and efficient moisture transport to high latitude glaciers therebycontributing to glacial buildup we combined our sea level results with deep sea n 18 o records as a means of estimating the temperature and ice volume components in the marine n 18 o record this analysis confirms large deep ocean temperature shifts following mis 5e and during termination i deep ocean temperatures changed bymuch smaller amounts between mis 5c and 2 maximum temperature shift in the deep pacific is about 2 whereas the shift at a site in the atlantic is 4 under glacial conditions temperatures at both sites are near the freezing point the shift in the atlantic is likelycaused bya combination of changing proportions of northern and southern source waters as well as changing temperature at the sites where these deep waters form

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

links between climate and sea levels for the past three million years the oscillations between glacial and interglacial climate conditions over the past three million years have been characterized by a transfer of immense amounts of water between two of its largest reservoirs on earth the ice sheets and the oceans since the latest of these oscillations the last glacial maximum between about 30 000 and 19 000 years ago approximately 50 million cubic kilometres of ice has melted from the land based ice sheets raising global sea level by approximately 130 metres such rapid changes in sea level are part of a complex pattern of interactions between the atmosphere oceans ice sheets and solid earth all of which have different response timescales the trigger for the sea level fluctuations most probably lies with changes in insolation caused by astronomical forcing but internal feedback cycles complicate the simple model of causes and effects