changing influence of antarctic and greenlandic temperature records on sea level over the last glacial cycle we use a simple model to analyse the relationship between ice core temperature proxy data and global ice volume eustatic sea level data over the last glacial cycle lgc by allowing the temperature forcing to be a mix of greenlandic and antarctic signals we optimise the proportion of this mixing to fit sea level data we find that sea level forcing is best represented by a mix of antarctic and greenlandic temperature signals through the whole glacial cycle we suggest that a distinct bipolar switch occurs which links eustatic sea level more closely with the antarctic like variability during the glacial period mis 4 3 and 2 and more closely to the greenland like variability during the last termination ti and the interglacial periods holocene and mis 5 this switch may be caused by the spatio temporal distribution of ice sheet collapse perhaps linked to glacial to interglacial changes in deep water distribution in the ocean which in turn drive changes in pole ward heat and moisture transport

late pleistocene landscape response to climate change eolian and alluvial fan deposition cape liptrap southeastern australia abstract sea cliffs along the western coast of cape liptrap at arch rock provide nearly continuous exposure of calcareous eolianites dated at 68 112 ka five optically stimulated luminescence osl ages calcareous eolian deposition began immediately after the last interglacial marine highstand oxygen isotope stage ois 5e and continued during sea level fall until the beginning of ois 4 west southwesterly winds transported calcareous sand across 12 km of exposed continental shelf by the beginning of ois 4 a brief period of cold arid windy continental climate with ephemeral but intense surface runoff immediately preceded the last glacial maximum lgm this resulted in fluvial reworking of the calcarenites into an alluvial fan dated at 23 25 ka four osl ages the fan overlies peat dated at 25 279 yr cal bp and is capped by a paleosol dated at 6010 yr cal bp concurrent eolian reworking by northwesterly winds of siliceous sediments on marine terraces along the eastern and central portion of cape liptrap formed siliceous longitudinal dunes with ages ranging from 19 to 24 ka five osl ages the phase of maximum landscape instability at cape liptrap coincides with solar insolation and air temperature minima and preceded the lgm by several thousand years

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

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

morphology of fore reef slopes and terraces takapoto atoll tuamotu archipelago french polynesia central pacific the tectonic sea level and coral growth control abstract a dataset of 41 bathymetric profiles detected by satelline imagery and echo sounding to a maximum depth of 38 m along the fore reef slopes of takapoto atoll tuamotu plateau french polynesia central pacific were qualitatively and quantitatively analyzed in order to identify the main geomorphological features in addition scuba diving investigations from a selected site resulted in defining coral composition and cover rate six distinct fore reef sectors were morphologically differentiated on the basis of seaward extension and slope gradient only the north end and a restricted area of the mid south east side extend seawards over an average distance of 150 m with a relatively low gradient 23 38 most of the outer slope areas are narrow 10 m high outer reef crest like reliefs 0 5 m 1 5 m high pinnacles 2 m 17 m high coral heads

chironomids record terrestrial temperature changes throughout arctic interglacials of the past 200 000 yr quaternary interglacial periods provide glimpses of a warmer arctic and useful perspectives on possible future conditions but records of arctic terrestrial conditions over multiple interglacial periods are rare here we take advantage of a site in the canadian arctic where lacustrine sediments representing the past three interglacial periods are preserved in an extant lake we use subfossil insects chironomids preserved in this exceptional sedimentary archive to derive temperature reconstructions through the holocene up to a d 2005 through the last interglacial sensu stricto marine isotope stage or mis 5e and a portion of the penultimate interglacial mis 7 chironomid inferred temperatures are warmest for the early holocene and mis 5e two periods with enhanced northern hemisphere insolation forcing relative to today twentieth century warming at this site apparently caused the recent extirpation of cold stenothermous chironomid taxa assemblages from mis 5e have close analogs in modern training set data as determined by squared chord distance and mis 5e species assemblages are very similar to holocene assemblages at this site mis 7 sediments record summer temperatures similar to those of the mid to late holocene followed by a descent into glacial conditions even mis 7 chironomid assemblages dating back 200 000 yr have close modern analogs these lake sediments also provide direct evidence for a period of regional deglaciation between mis 5e and the holocene most likely mis 5a to our knowledge the data presented here represent the longest paleotemperature record thus far generated using chironomids the existence of close modern analogs for ancient chironomid assemblages at lake cf8 suggests that this method can provide useful paleotemperature estimates extending back hundreds of millennia

last interglacial climates the last interglacial commonly understood as an interval with climate as warm or warmer than today is represented by marine isotope stage mis 5e which is a proxy record of low global ice volume and high sea level it is arbitrarily dated to begin at approximately 130 000 yr b p and end at 116 000 yr b p with the onset of the early glacial unit mis 5d the age of the stage is determined by correlation to uranium thorium dates of raised coral reefs the most detailed proxy record of interglacial climate is found in the vostok ice core where the temperature reached current levels 132 000 yr ago and continued rising for another two millennia approximately 127 000 yr ago the eemian mixed forests were established in europe they developed through a characteristic succession of tree species probably surviving well into the early glacial stage in southern parts of europe after ca 115 000 yr ago open vegetation replaced forests in northwestern europe and the proportion of conifers increased significantly farther south air temperature at vostok dropped sharply pulses of cold water affected the northern north atlantic already in late mis 5e but the central north atlantic remained warm throughout most of mis 5d model results show that the sea surface in the eastern tropical pacific warmed when the ice grew and sea level dropped the essentially interglacial conditions in southwestern europe remained unaffected by ice buildup until late mis 5d when the forests disappeared abruptly and cold water invaded the central north atlantic ca 107 000 yr ago

geochemical evidence for airborne dust additions to soils in channel islands national park california there is an increasing awareness that dust plays important roles in climate change biogeochemical cycles nutrient supply to ecosystems and soil formation in channel islands national park california soils are clay rich vertisols or alfi sols and mollisols with vertic properties the soils are overlain by silt rich mantles that contrast sharply with the underlying clay rich horizons silt mantles contain minerals that are rare or absent in the volcanic rocks that dominate these islands immobile trace elements sc th la and ta nd cr and rare earth elements show that the basalt and andesite on the islands have a composition intermediate between upper continental crust and oceanic crust in contrast the silt fractions and to a lesser extent clay fractions of the silt mantle have compositions closer to average upper continental crust and very similar to mojave desert dust island shelves exposed during the last glacial period could have provided a source of eolian sediment for the silt mantles but this is not supported by mineralogical data we hypothesize that a more likely source for the silt rich mantles is airborne dust from mainland california and baja california either from the mojave desert or from the continental shelf during glacial low stands of sea although average winds are from the northwest in coastal california easterly winds occur numerous times of the year when santa ana conditions prevail caused by a high pressure cell centered over the great basin the eolian silt mantles constitute an important medium of plant growth and provide evidence that abundant eolian silt and clay may be delivered to the eastern pacifi c ocean from inland desert sources

coastal quaternary morphologies on the northern coast of the south china sea china and their implications for current tectonic models a review and preliminary study marine terraces tidal notches and sediments along a 1200 km long stretch of the northern coast of the south china sea passive margin were studied and divided into five areas with varying tectonic characters up to three marine terraces occur that have elevations reaching up to 60 m above mean sea level amsl and two marine notches occur up to 11 m amsl chronology of the morphologies and deposits was obtained mainly by comparison with quaternary sea levels derived from the oxygen isotope curve however prior to the last interglacial highstand mis 5e c 125 ka evidence of history of events is less well constrained leading to less precision on sea level positions prior to mis 5e using the morphological features of mis 5e as a marker mean coastal uplift rates in the last c 125 ka range from 0 07 mm yr to 0 18 mm yr the pattern of deformations is slightly higher than those observed on passive margin coasts in other parts of the world the cause of uplift of the south china coastline is not clear but may relate to the himalayan collision zone or any other large scale phenomena

did glacials start with global warming abstract correlation of paleoclimatic evidence with orbital changes shows that the build up of polar ice accelerated when low obliquity coincided with perihelion in northern hemisphere winter under low obliquity the insolation was channeled to the tropics at the expense of both polar caps as perihelion moved from winter solstice toward spring equinox the solar beam in astronomic winter and spring became stronger than in summer and autumn this orbital configuration under climate conditions like today would lead to warming of tropical oceans but cooling of the polar regions the areally weighted global mean surface temperature which is dominated by the low latitudes would increase consequently during the first millennia the early glacial ice build up was most likely accompanied by global warming it was the associated increase of meridional insolation and temperature gradients which were instrumental in the transition to a glacial a significant part of the current global warming is due to the gradual temperature increase of the tropical oceans as the changing orbital configuration today resembles that of the last interglacial glacial transition the warming is likely to have a natural component

high precision u series dating of corals from western australia and implications for the timing and duration of the last interglacial abstract u series ages using methods of thermal ionisation mass spectrometry tims are reported for last interglacial fossil reefs along the stable coastal margin of western australia thorium isotope ratios were measured with superior precision using methods of charge collection high levels of precision in the measurement of both uranium and thorium isotopes has reduced the age uncertainty due to analytical errors excluding the uncertainty in the decay constants by a factor of four over the precisions reported by many earlier tims workers uncertainties in 234u t determined from both 230th 238u and 234u 238u are also significantly smaller than previously reported allowing samples which have undergone diagenetic exchange of uranium and thorium to be more easily identified strict criteria were adopted to screen the new western australian data reliable ages range from 127 to 122 ka published tims observations from other localities have been assessed using the same strict criteria when these are combined with glacio hydro isostatic sea level models they indicate that the last interglacial period occurred from at least 130 to 117 ka however these age constraints are largely determined from single data points and need to be verified with additional ages before considering them to be robust estimates for the timing of onset and termination of the last interglacial globally the main episode of reef growth appears to be confined to a narrow interval occurring from 127 to 122 ka in direct agreement with the narrow range in ages obtained from the western australian sites this may indicate that the last interglacial was of short duration extending from 127 to 122 ka only alternatively this interval may reflect a major reef building event in the middle of a longer duration 130 117 ka interglacial interval

episodic intraplate deformation of stable continental margins evidence from late neogene and quaternary marine terraces cape liptrap southeastern australia the waratah fault is a northeast trending high angle reverse fault in the late paleozoic lachlan fold belt at cape liptrap on the southeastern australian coast it is susceptible to reactivation in the modern intraplate stress field in southeast australia and exhibits late pliocene to late pleistocene reactivation radiocarbon optically stimulated luminescence osl and cosmogenic radionuclide crn dating of marine terraces on cape liptrap are used to constrain rates of displacement across the reactivated waratah fault six marine terraces numbered qt6 tt1 youngest to oldest are well developed at cape liptrap with altitudes ranging from 1 5 m to 170 m amsl respectively on the lowest terrace qt6 barnacles in wave cut notches 1 5 m amsl yielded a radiocarbon age of 6090 5880 cal bp and reflect the local mid holocene sea level highstand qt5 yielded four osl ages from scattered locations around the cape ranging from 80 ka to 130 ka it formed during the last interglacial sea level highstand mis 5e at 125 ka inner edge elevations approximate paleo high tide line for qt5 occur at distinctly different elevations on opposite sides of the waratah fault offsets of the inner edges across the fault range from 1 3 m to 5 1 m with displacement rates ranging from 0 01 mm a to 0 04 mm a the most extensive terrace tt4 yielded four early pleistocene cosmogenic radionuclide crn ages two apparent burial ages of 0 858 ma 0 16 ma and 1 25 ma 0 265 ma and two apparent exposure ages of 1 071 ma 0 071 ma 10be and 0 798 ma 0 066 ma 26al allowing for muonic production effects from insufficient burial depths the depth corrected crn burial ages are 1 8 ma 0 56 ma and 2 52 ma 0 88 ma or late pliocene a late pliocene age is our preferred age offsets of tt4 across the waratah fault range from a minimum of 20 m for terrace surface treads to a maximum of 70 m for terrace bedrock straths calculated displacement rates for tt4 range from 0 01 mm a to 0 04 mm a using a late pliocene age 2 ma identical to the rates calculated for the last interglacial terrace qt5 this indicates that deformation at cape liptrap has been ongoing at similar time averaged rates at least since the late pliocene the upper terraces in the sequence tt3 110 m amsl tt2 140 m and tt1 180 m are undated but most likely correlate to sea level highstands in the neogene terraces tt1 tt4 show an increasing northward tilt with age the waratah fault forms a prominent structural boundary in the lachlan fold belt discernible from airborne magnetic and bouger gravity anomalies seismicity and deformation are episodic episodic movement on the waratah fault may be coincident with sea level highstands since the late pliocene possibly from increased loading and elevated pore pressure within the fault zone this suggests that intervals between major seismic events could be on the order of 100 ka

does kamchatka belong to north america an extruding okhotsk block suggested by coastal neotectonics of the ozernoi peninsula kamchatka russia this paper addresses one part of an outstanding tectonic problem regarding the nature of the plate boundary between eurasia and north america in northeastern russia in this region the northwestern corner of the pacific plate interacts either simply with the north american plate or more complexly with one or more blocks independent of north america north of this corner evidence of uplift tilting and convergence contradicts the prevailing simpler model on the ozernoi peninsula similar to 150 km north of the subducting pacific plate marine terraces indicate uplift rates of 0 1 to 0 3 mm yr with faster rates to the east historic and paleoseismic records provide evidence for recurring tsunamigenic thrust earthquakes offshore of the ozernoi peninsula the most recent a mw 7 7 earthquake in 1969 a multiplate model where an eastward moving okhotsk block including most of kamchatka is converging with a clockwise rotating bering block better explains these observations than does the unbroken north american plate model

segmentation of the 2010 maule chile earthquake rupture from a joint analysis of uplifted marine terraces and seismic cycle deformation patterns abstract the segmentation of major fault systems in subduction zones controls earthquake magnitude and location but the causes for the existence of segment boundaries and the relationships between long term deformation and the extent of earthquake rupture are poorly understood we compare permanent and seismic cycle deformation patterns along the rupture zone of the 2010 maule earthquake m8 8 which ruptured 500 km of the chile subduction margin we analyzed the morphology of mis 5 marine terraces using lidar topography and established their chronology and coeval origin with twelve luminescence ages stratigraphy and geomorphic correlation obtaining a virtually continuous distribution of uplift rates along the entire rupture zone the mean uplift rate for these terraces is 0 5 m ka this value is exceeded in three areas which have experienced rapid emergence of up to 1 6 m ka they are located at the northern central and southern sectors of the rupture zone referred to as topocalma carranza and arauco respectively the three sectors correlate with boundaries of eight great earthquakes dating back to 1730 the topocalma and arauco sectors located at the boundaries of the 2010 rupture consist of broad zones of crustal warping with wavelengths of 60 and 90 km respectively these two regions coincide with the axes of oroclinal bending of the entire andean margin and correlate with changes in curvature of the plate interface rapid uplift at carranza in turn is of shorter wavelength and associated with footwall flexure of three crustal scale normal faults the uplift rate at carranza is inversely correlated with plate coupling as well as with coseismic slip suggesting permanent deformation may accumulate interseismically we propose that the zones of upwarping at arauco and topocalma reflect changes in frictional properties of the megathrust resulting in barriers to the propagation of great earthquakes slip during the 1960 m9 5 and 2010 events overlapped with the 90 km long zone of rapid uplift at arauco similarly slip in 2010 and 1906 extended across the 60 km long section of the megathrust at topocalma but this area was completely breached by the 1730 m 9 event which propagated southward until carranza both arauco and topocalma show evidence of sustained rapid uplift since at least the middle pleistocene these two sectors might thus constitute discrete seismotectonic boundaries restraining most but not all great earthquake ruptures based on our observations such barriers might be breached during multi segment super cycle events

melting ice sheets 400 000 yr ago raised sea level by 13 m past analogue for future trends abstract marine isotope stage mis 11 was possibly the longest 423 000 362 000 yr ago and warmest interglacial of the entire quaternary period this resulted from a special arrangement of earth s orbital parameters similar to the present interglacial mis 1 suggesting that mis 11 provides an analogue for future natural climate forcing and sea levels although precise documentation of mis 11 sea level history is therefore crucial especially considering additional impetus from anthropogenic warming the maximum mis 11 sea level remains highly contentious estimates from onshore indicators have ranged from below present sea level to about 20 m resulting from uncertainties in reliability of sea level indicators estimates of their subsequent displacement by vertical crustal motion and in dating we used a clear and unambiguous sea level indicator interface between subtidal and intertidal deposits in well exposed regressive raised shoreline deposits along south africa s southern coast the coast is stable in terms of tectonic setting and falls within a zone of low predicted glacio isostatic adjustment gia and low sensitivity for plausible model parameters the sea level indicators were directly dated using thermally transferred optically stimulated luminescence tt osl which gave a mean age of 390 ka corresponding with mis 11 we determined a precise maximum elevation of 14 m for the mis 11 sea level indicator which corrected for minor crustal uplift and gia yielded a eustatic sea level of 13 m 2 m the complete mis 11 transgressive regressive shoreline succession is preserved and the wave cut platform extends 950 m inland from the present shoreline indicating a prolonged highstand we have also documented sea level fluctuations during mis 11 including an earlier lower highstand close to present sea level which may explain the lower elevation range of some previous estimates at one locality mis 11 deposits form a sea cliff against which mis 5e sediments at an elevation of 6 2 m abut the 13 m mis 11 sea level tallies with total melting of the greenland and west antarctica ice sheets regarded as most susceptible to melting our data predict notably higher sea levels in the future regardless of anthropogenic influence on climate

the last interglacial sea level high stand on the southern cape coastline of south africa abstract the continental margin of southern south africa exhibits an array of emergent marginal marine sediments permitting the reconstruction of long term eustatic sea level changes we report a suite of optical luminescence ages and supplementary amino acid racemization data which provide paleosea level index points for three sites on this coastline deposits in the swartvlei and groot brak estuaries display tidal inlet facies overlain by shoreface or eolian facies contemporary facies relations suggest a probable high stand 6 0 8 5 m above modern sea level amsl at cape agulhas evidence of a past sea level high stand comprises a gravel beach ca 3 8 m amsl and an overlying sandy shoreface facies up to 7 5 m amsl osl ages between 138 7 ka and 118 7 ka confirm a last interglacial age for all marginal marine facies the high stand was followed by a sea level regression that was associated with the accumulation of eolian dunes dating to between 122 7 ka and 113 6 ka these data provide the first rigorous numerical age constraints for last interglacial sea level fluctuations in this region revealing the timing and elevation of the last interglacial high stand to broadly mirror a number of other far field locations

sea level rise due to polar ice sheet mass loss during past warm periods background although thermal expansion of seawater and melting of mountain glaciers have dominated global mean sea level gmsl rise over the last century mass loss from the greenland and antarctic ice sheets is expected to exceed other contributions to gmsl rise under future warming to better constrain polarice sheetresponse to warmer temperatures we draw on evidence from in terglacial periods in the geologic record that ex perienced warmer polar temperatures and higher gmsls than present coastal records of sea level from these previous warm periods dem onstrate geographic variability because of the influence of several geophysical processes that operate across a range of magnitudes and time scales inferring gmsl and ice volume changes from these reconstructions is nontrivial and generally requires the use of geophysical models advances interdisciplinary studies of geo logic archives have ushered in a new era of deciphering magnitudes rates and sources of sea level rise advances in our understanding of polar ice sheet response to warmer climates have been made through an increase in the number and geographic distribution of sea level reconstructions better ice sheet constraints and the recognition that several geophysical processes cause spatially complex patterns in sea level in particular accounting for glacial isostatic processes helps to decipher spatial variability in coastal sea level records and has reconciled a number of site specific sea level reconstructions for warm periods that have oc curred within the past several hundred thou sand years this enables us to infer that during recent interglacial periods small increases in

geomorphological evidence for late quaternary tectonic deformation of the cape region coastal west central australia abstract a late pleistocene marine isotope stage 5e emergent marine sequence fringes the coastline of the cape region of coastal west central australia and provides elevation and age control to characterize the locations and rates of crustal deformation there is a systematic measurable change in relative paleo sea level elevations across the cape region high precision leveling of modern and pleistocene shoreline features indicates the minimum elevation range of mis 5e shoreline features along the coast is 10 4 m this compares with the 2 5 m elevation range for observed modern shoreline analogs the lack of continuity of mis 5e shoreline elevations along 300 km of coastline demonstrates continuing tectonic deformation along coastal anticlines in the cape region topographic expression of mis 5e features indicates tectonic uplift consistent with late neogene to quaternary deformation on the cape cuvier and cape range anticlines post mis 5e tectonic uplift rates are up to 0 054 0 035 mm yr at fold axial locations estimated subsidence rates are 0 013 0 034 mm yr on fold limbs while the estimated vertical tectonic deformation is small and the rates are low the geomorphological data also demonstrate tectonic activity not stability

new uranium series ages of the waimanalo limestone oahu hawaii implications for sea level during the last interglacial period abstract the waimanalo formation limestone of oahu has been correlated with the last interglacial period based on u series dating of corals by t l ku and colleagues the limestone consists of growth position corals and overlying coral conglomerate an apparent bimodal distribution of ages for the growth position corals mean age 133 ka and the overlying coral conglomerate mean age 119 ka has been interpreted to represent two distinct high stands of sea that occurred within the last interglacial period both growth position corals and overlying conglomerate coral occur in an outcrop east of kaena point and consist mainly of pocillopora and porites u series ages of growth position corals that show closed system conditions are 120 3 ka and 127 4 ka overlying conglomerate corals have u series ages that range from 120 3 ka to 138 4 ka at kahe point conglomerate corals have ages of 120 3 ka and 134 4 ka these data show that the growth position corals are not systematically older than the conglomerate corals thus there is no evidence for two distinct high stands of sea waimanalo deposits at kahe point and mokapu point new u series ages of 134 4 ka and 127 3 ka have beach deposits as high as 12 5 m and at mokapu point growth position corals as high as 8 5 m a last interglacial sea level stand of 8 5 to 12 5 m conflicts with estimates of 6 m from a number of tectonically stable coastlines and islands in the western atlantic ocean we infer therefore that oahu may be undergoing uplift at a low rate this uplift may be due to compensatory lithospheric flexure because the island of hawaii has been subsiding throughout much of the quaternary from volcanic loading because of this possible uplift oahu and islands like it elsewhere in the pacific cannot be used as reference points for sea level during the last interglacial period

process like modeling of flank margin caves from genesis to burial evolution abstract a major challenge in groundwater and petroleum modeling is how to represent the diagenesis effect sensu lato and its associated features e g karst cavities porosity and permeability characteristics both geometrical descriptions and genesis are necessary for modeling diagenetic features because they allow the restitution of phenomenon in subsurface settings where they cannot be fully observed this study focuses on flank margin caves developed on carbonate islands as in the case of the bahamian islands over the last twenty years numerous measurements and observations have been carried out on quaternary carbonate islands these together with reasonable hypotheses of genesis fresh water lens dissolution make island karst an appropriate subject for developing concepts and modeling methods which can be then applied to other diagenetic features such as reflux dolomitization and hydrothermal fluid effects the speleogenesis of flank margin caves was modeled following deterministic and stochastic methods to achieve a description of dissolution genesis a fresh water lens surface was built based on the topography of long island bahamas and was then used to simulate virtual development of flank margin caves at several formation phases including uncertainty coefficients applied to both fresh water lens location and stability time by using 3d probability cubes the cave simulations were compared with over sixty bahamian cave surveys in order to substantiate our modeling processes and results finally the model was exposed to a cave collapse situation the likelihood of preservation and the extent of the area affected were measured to provide an evaluation of the spatial distribution of associated petrophysical characteristics e g porosity and permeability the results reveal close resemblance and coherence between modeled and field data including collapse features therefore the optimum method for restituting diagenetic features is by stochastic modeling actively driven by process concepts and most up to date methods

protactinium 231 dating of carbonates by thermal ionization mass spectrometry implications for quaternary climate change measurement of protactinium 231 231pa in carbonates by thermal ionization mass spectroscopy yields 231pa ages that are more than 10 times more precise than those determined by decay counting carbonates between 10 and 250 000 years old can now be dated with 231pa methods barbados corals that have identical 231pa and thorium 230 230th ages indicate that the timing of sea level change over parts of the last glacial cycle is consistent with the predictions of the astronomical theory two devils hole calcite subsamples record identical 231pa and 230th ages suggesting that the chronology of this climate record is accurate

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

the last interglacial climate during the last 10 000 years the holocene has been relatively mild and stable in contrast the climate during the last interglacial is often portrayed as more variable but as kukla discusses in this perspective evidence for a more stable last interglacial is emerging furthermore the transition to the next glacial proceeded in stages and was not uniform across europe

high precision u series dating of last interglacial events by mass spectrometry houtman abrolhos islands western australia the houtman abrolhos islands situated at the western passive margin of the australian continent consist of a series of shelf edge coral reefs the central platforms of the reefs are late pleistocene in age and are generally some 3 5 m above present sea level the uppermost part of the last interglacial reefs normally has an upward shallowing sequence consisting of coral framestone coralline algal bindstone and skeletal grainstone to rudstone this sequence represents deposition in water depths of less than 2 m and provides a good indicator of sea level high precision mass spectrometric dates of corals from the abrolhos reefs including dates obtained from drill cores arological isotopic and stratigraphic criteria are established for the selection of suitable samples for dating and for assessing the reliability of dates using the screened dates and the stratigraphic evidence the timing and character of the sea level variations of the last interglacial in the abrolhos region are examined the data show that sea level of the last interglacial in the abrolhos was 4 m below its present height by ca 134 ka bp and probably reached about 2 m above present height at ca 133 ka bp the exact time at which sea level reached its peak 6 m above present sea level cannot be determined from our data but it is clear that the sea level high stand of the last interglacial lasted until ca 116 ka bp and that for much of the last interglacial sea level at the abrolhos was at a height of about 4 m above its present level

orbital forcing of the marine isotope stage 9 interglacial milankovitch orbital forcing theory has been used to assign time scales to many paleoclimate records however the validity of this theory remains uncertain and independent sea level chronologies used to test its applicability have been restricted largely to the past approximately 135 000 years here we report u series ages for coral reefs formed on henderson island during sea level high stands occurring at approximately 630 000 and approximately 330 000 years ago these data are consistent with the hypothesis that interglacial climates are forced by northern hemisphere summer solar insolation centered at 65 degrees n latitude as predicted by milankovitch theory

timing and duration of last interglacial conditions in europe a chronicle of a changing chronology abstract estimates of the length of the last interglacial in europe conventionally defined by the presence of forest as inferred from pollen diagrams have varied considerably here an account of recent developments largely instigated by a paper by kukla et al 1997 is presented these include the emergence of new records with improved chronologies and a re evaluation of previous assumptions of synchroneity between marine and terrestrial stage boundaries and also between northern and southern european changes the current scheme proposes that the onset of the last interglacial in europe started well into mis 5e after deglaciation was complete and was coincident with a rise to peak sea surface temperatures however the timing of the end of the last interglacial between northern and southern europe appears to have diverged considerably in the north the elimination of forest occurred ca 115 ka near the time of the mis 5e 5d transition while in the south tree populations persisted into the interval of global ice growth until the onset of significant ice rafting ca 110 ka this significant n s diachroneity may be a reflection of the effects of different bioclimatic parameters limiting tree growth in the two areas these developments highlight the problems of correlating records of different proxies and from different geographical regions

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

impacts of eustasy and hydro isostasy on the evolution and landforms of pacific atolls consideration of eustatic and hydro isostatic effects on late quaternary sea levels in the tropical pacific ocean indicates that the configuration of modern atolls with emergent annular reef flats is a transient morphology not developed until post mid holocene time annular atoll reefs perched atop carbonate platforms which cap buried volcanic edifices are underlain by 8 28 m of holocene limestone disconformably overlying a substratum of last interglacial or older limestone comparable thicknesses 9 23 m of holocene sediment are present beneath atoll lagoons that are uniformly 85 m deep during glacio eustatic drawdowns in global sea level by 120 125 m carbonate platforms of modern atoll provinces rose abruptly from the sea as clusters of subaerial limestone plateaus flanked by steep cliffs modern analogues are provided by emergent atolls uplifted on the flexural arches of trench forebulges slow subsidence coupled with karstic erosion of emergent atolls during the last glaciation lowered the surfaces of last interglacial reef edifices by the amounts needed to provide accommodation space for holocene reef growth during the postglacial eustatic rise in sea level modern atoll reef caps began to grow after 9 ka when rising holocene sea level overtopped degraded remnants of interglacial reefs but remained submerged until carbonate buildups approached sea level in mid holocene time 6 4 ka classic atoll morphology with circlets of multiple islets dotting annular reefs formed in combination with late holocene hydro isostatic drawdown in tropical pacific sea level in response to equatorial ocean siphoning a facet of global isostatic adjustment gia to deglaciation early holocene eustatic rise in sea level and late holocene hydro isostatic decline in sea level combined to produce a regionally variable mid holocene highstand in tropical pacific sea level that stood 1 0 2 6 m above modern sea level cemented mid holocene paleoreef flats now stranded well above sea level serve as resistant foundations for non migratory pinned islets that were not present along atoll rims until after the local crossover date when ambient high tide level first fell below mid holocene low tide level existing atoll landforms have a time depth generally 1 2 ka

a cool eastern pacific ocean at the close of the last interglacial complex abstract new high precision thermal ionization mass spectrometric tims u series ages of solitary corals balanophyllia elegans from several marine terrace localities along the california and southern oregon coasts date to the 80 000 yr bp high stand of sea correlative with marine isotope substage 5a late in the last interglacial complex ages of multiple corals from localities north of point ano nuevo central california and san nicolas island southern california suggest that this high sea stand could have lasted at least 8000 yr from 84 000 to 76 000 yr bp these ages overlap with those from marine deposits on tectonically stable bermuda and tectonically emergent barbados higher elevation terraces at two california localities in the palos verdes hills and on san nicolas island have corals with ages that range mostly from 121 000 to 116 000 yr bp correlative with marine isotope substage 5e these ages are similar to those reported for other terraces in southern california but are younger than some ages reported from hawaii barbados and the bahamas marine terrace faunas are excellent proxies for nearshore marine paleotemperatures during past high sea stands terraces on the palos verdes hills and san nicolas island dated to the 120 000 yr bp high sea stand have dominantly zoogeographically neutral species in exposed coastal localities indicating nearshore waters similar to those of today in contrast 80 000 yr bp exposed coastal localities typically have molluscan faunas characterized by numerous extralimital northern species and a lack of extralimital southern species these fossil assemblages are indicative of nearshore water temperatures that were cooler than modern temperatures at 80 000 yr bp waters at least as warm as today s at 120 000 yr bp and cooler than present at 80 000 yr bp are in excellent agreement with marine alkenone records and coastal vegetation records derived from pollen data from both southern and northern california decreased insolation or increased upwelling seem inadequate to explain the cool waters off the pacific coast from southern oregon to southern california at 80 000 yr bp we propose that a stronger california current or at least one with a greater component of subarctic waters may explain cooler than modern coastal waters during the 80 000 yr bp high sea stand

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

late quaternary beach deposits and archaeological relicts on the coasts of cyprus and the possible implications of sea level changes and tectonics on the early populations

support for the giant wave hypothesis evidence from submerged terraces off lanai hawaii the origin of subaerial coral conglomerate deposits on the hawaiian islands of lanai and molokai is controversial primarily because these deposits are difficult to interpret and the vertical motion of these islands is poorly constrained based on bathymetry dive observations sedimentary and radiocarbon data from coralline algal dominated deposits from two submerged terraces at 150 and 230 m off lanai lanai has experienced relatively little vertical movement over the last 30 ka using internally consistent age versus depth relationships paleowater depths and published sea level data we estimate that lanai has experienced maximum rates of uplift of 0 1 m kyr or subsidence of 0 4 m kyr over this period our analysis of possible uplift mechanisms published geophysical numerical modelling and recent tide data suggests that this is also the maximum uplift rate for the last several hundred thousand years taken together these data support the interpretation that coral conglomerates at elevations higher than 35 m on lanai are tsunami deposits with a minimum wave run up 170 m rather than shoreline deposits formed during the last two interglacials then uplifted to their present elevations

control of paleoshorelines by trench forebulge uplift loyalty islands abstract unlike most tropical pacific islands which lie along island arcs or hotspot chains the loyalty islands between new caledonia and vanuatu owe their existence and morphology to the uplift of pre existing atolls on the flexural forebulge of the new hebrides trench the configuration and topography of each island is a function of distance from the crest of the uplifted forebulge both mare and lifou are fully emergent paleoatolls upon which ancient barrier reefs form highstanding annular ridges that enclose interior plateaus representing paleolagoon floors whereas the partially emergent ouvea paleoatoll rim flanks a drowned remnant lagoon emergent paleoshoreline features exposed by island uplift include paleoreef flats constructed as ancient fringing reefs built to past low tide levels and emergent tidal notches incised at past high tide levels present paleoshoreline elevations record uplift rates of the islands since last interglacial and mid holocene highstands in global and regional sea levels respectively and paleoreef stratigraphy reflects net quaternary island emergence the empirical uplift rates vary in harmony with theoretical uplift rates inferred from the different positions of the islands in transit across the trench forebulge at the trench subduction rate the loyalty islands provide a case study of island environments controlled primarily by neotectonics

timing and duration of the last interglacial evidence for a restricted interval of widespread coral reef growth abstract we report new mass spectrometric u series ages for eight last interglacial fossil reefs along the continental margin of western australia corals were selected in growth position from localities that are characterized by apparently low levels of diagenesis and relative tectonic stability so that the fossil reefs provide critical information on last interglacial sea levels without requiring corrections for tectonic movements in addition we have improved the constraint on the timing of onset of reef growth by recovering drill core coral from the base of the reefs uranium and thorium isotopes were measured with high levels of precision leading to improvements in age resolution and allowing samples which have undergone diagenetic exchange of uranium and thorium to be more easily identified and discarded these data supplement our previous results for rottnest island and leander point leading to more than seventy mass spectrometric u series ages from which constraints can be placed on the timing duration and character of the last interglacial sea level highstand reliable ages show that reef growth started contemporaneously at 128 1 ka along the entire western australian coastline while relative sea levels were at least 3 m above the present level because western australia is located far from the former penultimate glacial maximum ice sheets and are not significantly effected by glacial unloading these data constrain the timing of onset of the last interglacial period to 128 1 ka assuming reef growth started soon after sea level approached interglacial levels a unique regressive reef sequence at mangrove bay constrains the timing of termination of the last interglacial period to 116 1 ka the major episode of reef building however both globally and locally along the western australian coast is restricted to a very narrow interval occurring from 128 ka and 121 ka suggesting that global ocean surface temperatures were warm and or sea levels were stable enough to allow prolific reef growth only during the earlier part of the last interglacial

sea level changes since the last glacial maximum an appraisal of the ipcc fourth assessment report the ipcc fourth assessment report ar4 stated that global sea level rose by about 120 m between the last glacial maximum lgm and 3 2 ka and did not rise again until the late 19th century a review of relevant literature demonstrates that the rise may have been larger by 10 15 m that the timing of stabilisation is poorly constrained within the last 7 ka bp and that the onset of modern rates of sea level rise is not synchronous and uniform across the globe the lgm lowstand as defined in the ar4 is based on the classic barbados sea level history but the sea level curve from this island may not be an accurate eustatic approximation if glacial isostatic adjustment gia processes were significant as suggested by various authors the barbados sea level curve revealed the existence of meltwater pulse mwp 1a at around 14 000 cal a bp questions about the source and causal mechanism of mwp 1a are still being explored by field scientists and gia modellers these problems have direct relevance for contemporary measurements of ice mass changes because space geodetic measurements rely on information provided by gia models to separate land motion from ice mass changes global patterns of holocene sea level change are controlled by regional sea level variability not only through isostatic and tectonic processes but also through steric effects longer wavelength gravitational changes produced by changing ice ocean mass flux and hemispheric scale perturbations in the earth s rotation eustasy is therefore merely a concept not a measurable quantity constraining the late holocene ice melt contribution to global sea level rise and determining regional sea level rise patterns in the 18th and 19th centuries are important future tasks for sea level scientists these will establish the baseline contributions to 20th and 21st century sea level rise and will help to determine the causes of modern rates of sea level rise constraining historical sea level accelerations and short term ice mass flux will aid models of ice sheet dynamics and help to reduce current uncertainties in future sea level predictions the ar4 shows that regional sea level variability is clearly present in sea level change patterns for the past 50 a and an important challenge for the next ipcc assessment is to incorporate this variability into regional future sea level rise scenarios copyright 2009 john wiley sons ltd

coseismic vs climatic factors in the record of relative sea level changes an example from the last interglacials in se spain abstract trying to decipher how paleoseismic activity has influenced the altitudinal disposition of interglacial deposits is one of the main challenges to be confronted before quantifying relative sea level changes between consecutive highstands at the same time identifying paleoseismic features in an area with low instrumental seismic activity can complement the seismic record thereby contributing to better seismic hazard knowledge in this regard cope basin se spain meets all the requirements necessary for these kinds of analysis firstly on account of its excellent outcrop conditions and secondly because its sea level record is undoubtedly conditioned by both factors climatically driven changes and local and regional seismotectonics the morpho sedimentary sequence presented in this paper provides evidence from three different highstands two littoral sedimentary units separated by terrestrial deposits and affected by liquefaction paleoseismic activity and a younger paleo cliff and its associated wave cut platform carved into those sedimentary units this wave cut platform now tilted and folded reaches heights ranging from 0 to 8 m which has been interpreted as a consequence of cosesimic effect the age of this wave cut platform last interglacial or holocene supports uplift rate estimations of from 0 016 to 0 15 mm yr since the last interglacial holocene active deformation observed on pleistocene holocene sea level geomarkers can not only furnish useful information about seismic activity within the major structure of the aguilas arc but also offer new insight into the cope basin s geodynamic model

monitoring an oil sands reservoir in northwest alberta using time lapse 3d seismic and 3d p sv converted wave data time lapse 3d seismic monitoring was conducted in the japan canada oil sands limited jacos hangingstone steam assisted gravity drainage sagd operation area in alberta canada to delineate steam affected areas the time lapse surveys acquired in february 2002 and march 2006 show distinct response changes around the sagd well pairs in addition 3d p sv converted wave processing and analysis were applied on the second 3d data set recorded with three component digital sensors for a reservoir characterization study

hauts niveaux marins pleistocenes du littoral bresilien abstract the high sea level corresponding to the last pleistocene interglacial stade left the most important records represented by extensive beach ridge plains along the central and southern coasts of brazil during the maximum level which was dated at 123 000 yr b p by coral samples the relative sea level was situated 8 2 m above present level four generations of quaternary marine sandy deposits have been described in southern brazil state of rio grande do sul where they are known as barrier i ii iii and iv the barrier iv about 4 m high corresponds to the last great transgressive regressive phase whose maximum occurred about 5100 yr b p the barrier iii with a height of about 8 10 m corresponds to the penultimate transgressive regressive period whose maximum was produced about 123 000 yr b p the barrier ii about 13 15 m high and the barrier i about 20 25 m high situated at inner positions in relation to the previous ones have been formed during high sea levels older than 123 000 years along the coastal plains of the states of sergipe and bahia the high sea level older than 123 000 years is represented only by one phase through cliffs carved within the barreiras formation on the other side along the coastalp plains of sao paulo parana and santa catarina there are marine terraces with a minimum height of 13 m above present sea level which are certainly older than the barrier iii and are probably recording the transgressive regressive period of the barrier ii middle pleistocene

history of the greenland ice sheet paleoclimatic insights abstract paleoclimatic records show that the greenland ice sheet consistently has lost mass in response to warming and grown in response to cooling such changes have occurred even at times of slow or zero sea level change so changing sea level cannot have been the cause of at least some of the ice sheet changes in contrast there are no documented major ice sheet changes that occurred independent of temperature changes moreover snowfall has increased when the climate warmed but the ice sheet lost mass nonetheless increased accumulation in the ice sheet s center has not been sufficient to counteract increased melting and flow near the edges most documented forcings and ice sheet responses spanned periods of several thousand years but limited data also show rapid response to rapid forcings in particular regions near the ice margin have responded within decades however major changes of central regions of the ice sheet are thought to require centuries to millennia the paleoclimatic record does not yet strongly constrain how rapidly a major shrinkage or nearly complete loss of the ice sheet could occur the evidence suggests nearly total ice sheet loss may result from warming of more than a few degrees above mean 20th century values but this threshold is poorly defined perhaps as little as 2 c or more than 7 c paleoclimatic records are sufficiently sketchy that the ice sheet may have grown temporarily in response to warming or changes may have been induced by factors other than temperature without having been recorded

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

fluvial architecture of the upper permian raniganj coal measure in the damodar basin eastern india abstract the upper permian raniganj formation of the damodar basin consists of an interbedded assemblage of sandstone shale carbonaceous shale and coal facies the trough cross bedded sandstone bodies st facies formed by migration of dunes in sand bar point bars are widely developed in the lower part of raniganj formation the planar cross bedded facies sp of transverse and diagonal bars and massive sandstone of longitudinal bars abound in the upper part of the eastern raniganj and jharia coalfields the succeeding ripple cross laminated sr facies with or without reactivation surface alternating with thick beds of fine clastics suggestive of flood deposits is widespread in the western bokaro and north karanpura coalfields markov chain statistics reveals a fining upward cyclical order of superposition throughout the raniganj sequence the integrated results of paleocurrent channel morphology texture and petrography suggest that the raniganj sedimentation was brought about in an extensive unified alluvial plain drained by a system of west northwest flowing streams whose channel sinuosity increased and depth decreased progressively in a downcurrent direction from east to west post gondwana faulting and subsequent erosion account for the disconnected disposition of the coalfields

the timing of high sea levels over the past 200 000 years the 230 th ages and 234 u 238 u ratios were determined for barbados corals that grew during periods of high sea level within the last 200 000 years the similarity of the initial 234 u 238 u ratios of some of the corals to the modern marine value suggests that these samples are pristine and that the marine 234 u 238 u ratio 83 000 and 200 000 years ago was within 2 per mil of the modern value the accuracies of the 230 th ages are evaluated on the basis of the 234 u 238 u values and a model of the behavior of uranium and thorium isotopes during diagenesis for the last three interglacial and two intervening interstadial periods sea level peaked at or after peaks in summer insolation in the northern hemisphere this overall pattern supports the idea that glacial interglacial cycles are caused by changes in earth9s orbital geometry the sea level drop at the end of the penultimate interglacial the last interglacial and a subsequent interstadial period lagged behind the decrease in insolation by 5 000 to 10 000 years

eemian sea level highstand in the eastern baltic sea linked to long duration white sea connection abstract revised diatom and new dinoflagellate cyst and benthic foraminiferal data from the eastern baltic sea have refined our understanding of eemian last interglacial 131 119 5 ka sea level change on the russian karelia a former seaway linking the baltic to the white sea results from peski eastern baltic show the initiation of marine conditions just before 131 ka in the latest saalian after the opening of a connection to the north sea following the onset of the eemian marine highstand and the opening of the white sea connection at around 130 25 ka near fully marine conditions persisted in the eastern baltic area for ca 6 kyr until ca 124 ka for most of the eemian a strong thermal stratification in the eastern baltic resulted from an arctic and possible north atlantic water component from the white sea merging with warmer waters from the north sea from ca 124 ka decreasing salinity indicates the end of the marine highstand and a simultaneous closure of the baltic sea white sea connection i e a duration of ca 6 kyr for this seaway the main influence of white sea inflow appears to be restricted to the eastern baltic area although a large submerged area in the russian karelia associated with temperate atlantic waters could have assisted in creating a more oceanic climate for central europe

evidence for the timing and duration of the last interglacial period from high precision uranium series ages of corals on tectonically stable coastlines the last interglacial period has a timing and duration that can be estimated from u series dating of emergent coral bearing deposits on tectonically stable coastlines high precision dating from bermuda the bahamas hawaii and australia suggests that the last interglacial period had a sea level at least as high as present from 128 000 to 116 000 yr b p sea level reached a near present level more quickly after the close of the penultimate glacial period than at the close of the last glacial period and the duration of high sea level is longer than that implied by the deep sea record c 2002 university of washington

unraveling the tilting history of the submerged reefs surrounding oahu and the maui nui complex hawaii there is considerable uncertainty concerning the history of lithospheric flexure of oahu and the maui nui complex associated with the hawaiian hot spot previous reconstructions based on models and sparse observational data place the zone of maximum uplift forebulge either under oahu or between oahu and molokai to address this issue we have compiled and analyzed all existing and new high resolution multibeam bathymetry dive observations and chronologic data from submerged terraces in the region we have identified 89 separate submarine terraces and mapped their distribution across the volcanic flanks of oahu and the maui nui complex these data are used to systematically measure the direction and amplitude of terrace tilting within the maui nui complex and to provide new constraints on lithospheric flexure associated with volcanic loading at the hot spot the terraces are divided into six separate geographic regions oahu molokai penguin bank lanai maui and east maui defined by significant discontinuities in either terrace morphology or depth following the sequential development of new substrate as the new volcanoes formed throughout the development of the mnc 18 new and 51 published 87sr 86sr isotopic ages show that the terraces in these regions were also initiated at different times and the tilting data show that they also responded to lithospheric flexure independently the general pattern of terrace tilting records the plate s response to lithospheric flexure with each region continually tilting toward the zone of maximum subsidence since their formation our individual tilt calculations are based on the most complete and highest resolution bathymetric data available and they show that plate response to volcanic loading is a gradual process finally we demonstrate that the shallowest terraces we identified in the oahu and molokai regions tilt toward the north away from the current zone of maximum subsidence indicating that these regions have recently passed the zone of maximum uplift we compare our results with two separate published numerical models and differentiate between these resolving a long standing uncertainty in the position of the forebulge

segmentation of megathrust rupture zones from fore arc deformation patterns over hundreds to millions of years arauco peninsula chile 1 this work explores the control of fore arc structure on segmentation of megathrust earthquake ruptures using coastal geomorphic markers the arauco nahuelbuta region at the south central chile margin constitutes an anomalous fore arc sector in terms of topography geology and exhumation located within the overlap between the concepcion and valdivia megathrust segments this boundary however is only based on 500 years of historical records we integrate deformed marine terraces dated by cosmogenic nuclides syntectonic sediments published fission track data seismic reflection profiles and microseismicity to analyze this earthquake boundary over 10 2 10 6 years rapid exhumation of nahuelbuta s dome like core started at 4 1 2 ma coeval with inversion of the adjacent arauco basin resulting in emergence of the arauco peninsula here similarities between topography spatiotemporal trends in fission track ages pliocene pleistocene growth strata and folded marine terraces suggest that margin parallel shortening has dominated since pliocene time this shortening likely results from translation of a fore arc sliver or microplate decoupled from south america by an intra arc strike slip fault microplate collision against a buttress leads to localized uplift at arauco accrued by deep seated reverse faults as well as incipient oroclinal bending the extent of the valdivia segment which ruptured last in 1960 with an mw 9 5 event equals the inferred microplate we propose that mechanical homogeneity of the fore arc microplate delimits the valdivia segment and that a marked discontinuity in the continental basement at arauco acts as an inhomogeneous barrier controlling nucleation and propagation of 1960 type ruptures as microplate related deformation occurs since the pliocene we propose that this earthquake boundary and the extent of the valdivia segment are spatially stable seismotectonic features at million year scale

extralimital senegalese species during marine isotope stages 5 5 and 11 in the canary islands 29 n sea surface temperature estimates abstract the presence of harpa doris roding 1798 in marine deposits of the last interglacial period 130 120 ka marine isotope stage or mis 5 5 in the canary islands gran canaria lanzarote and fuerteventura enabled us to compare this occurrence with its present habitat in the gulf of guinea and the cape verde islands well to the south this comparison leads to the conclusion that sea surface temperatures ssts in the waters around the canary islands during the last interglacial period were at least 3 3 c higher than today h doris is found in association with the large gastropod persististrombus latus gmelin 1791 as well as the coral siderastrea radians pallas 1766 the presence of these extralimital southern warm water species in the canary islands during the last interglacial period also implies a northward expansion of plankton feeding larvae in seawater with a high chlorophyll a content such conditions would require a shortening of the southern arm of the cool canary current that dominates the waters around the canary islands at present marine deposits dating to 400 ka mis 11 are also found on the canary islands in these deposits the presence of saccostrea cucullata born 1778 allows a comparison with its present habitat in the gulf of guinea in this analysis we conclude that ssts in waters around the canary islands during this major interglacial period were at least 4 2 c higher than today middle pleistocene fossils of s cucullata have also been found in the western mediterranean sea and morocco as well as the cape verde islands if these deposits also date to mis 11 sst warming could have been a regional phenomenon including much of the eastern atlantic ocean and mediterranean sea

similarities and dissimilarities between the last two deglaciations and interglaciations in the north atlantic region abstract sea surface temperatures ssts recorded by alkenones and oxygen isotopes in the alboran basin are used here to describe at an unprecedented fine temporal resolution the present interglaciation pig initiated at 11 7 ka bp the last interglaciation lig onset approximately at 129 ka and respective deglaciations similarities and dissimilarities in the progression of these periods are reviewed in comparison with ice cores and stalagmites cold spells coeval with the heinrich events h described in the north atlantic include multi decadal scale oscillations not previously obvious up to 4 c in less than eight centuries within the stadials associated with h1 and h11 ca 133 ka and 17 ka respectively these abrupt oscillations precede the accumulation of organic rich layers deposited when perihelion moves from alignment with nh spring equinox to the summer solstice a reference for deglaciations events observed during the last deglaciation at 17 ka 14 8 ka and 11 7 ka are reminiscent of events occurred during the penultimate deglaciation at ca 136 ka 132 ka and 129 ka respectively the sst trend during the pig is no more than 2 c from 20 c to 18 c up to 0 2 c ka the trend is steeper during the lig i e up to a 5 c change from the early interglaciation to immediately before the glacial inception from 23 c to 18 c up to 0 4 c ka events are superimposed upon a long term trend towards colder ssts beginning with sst maxima followed by temperate periods until perihelion aligned with the nh autumn equinox before ca 5 3 ka for the pig and 121 ka for the lig a cold spell of around eight centuries at 2 8 ka during the pig was possibly mimicked during the lig at ca 118 ka by a sst fall of around 1 c in a millennium these events led interglacial sst to stabilise at around 18 c the glacial inception barely evident at the beginning ca 115 ka north atlantic event c25 after perihelion passage in the nh winter solstice culminated with a sst drop of at least 2 c in two millennia event c24 ca 111 ka the little ice age 0 7 ka also occurred after the latest perihelion passage in the nh winter solstice and could be an example of how a glacial pre inception event following an interglaciation might be

the last interglacial stage definitions and marine highstand north america and eurasia abstract delineation of the boundary between the last interglacial lig and the last wisconsinan glacial stage in north america represents a critical yet unresolved issue subdivisions of the late pleistocene are based on oxygen isotope ice cover and pollen stratigraphic data boundaries defined by isotope chronology hinge on complex interrelationships between 18o in foraminifer tests ice volumes stored on land and coeval sea level position in the absence of adequate pollen stratigraphic documentation pleistocene subdivision boundaries were harder to establish in north america than in europe time transgressive pollen zones revealed increased lengths of the climatically floristically defined lig from the european subarctic to the mediterranean conflicting definitions of sangamon as representing only the last interglacial of minimum ice cover and higher temperatures or broadly defined sensu lato also incorporating early part of the last wisconsinan glacial stage persist in the north american literature the exclusively interglacial age of the sangamon geosol originally used in dating the sangamonian stage proved untenable designation of an eowisconsinan interval corresponding to susbtages mis 5d a also lacks merit despite climate and vegetation related discrepancies pollen and coastal deposit based comparisons between europe and north america during mis 5 and the holocene are useful in establishing the climate history of the north american sangamonian and subsequent early wisconsinan substages an overarching mis 5 cooling trend represented by scattered subarctic and high mountain ice accumulation events followed the mis 5e eemian sangamonian temperature peak adoption of the general european practice that asymmetrically splits mis 5 into a short mis 5e interglacial and a long early wisconsinan glacial mis 5d a interval is preferred in north america as well subdivisions in the normalized 18o curve that serve as the chronological framework and the wealth of european pollen data support this approach while multiple pre sangamon pleistocene marine paralic intervals do occur on the nw gulf coast all pre sangamon pleistocene marine and brackish inshore deposits had been removed by erosion in the ne coastal plain a single inshore nearshore marine sediment and highstand interval is well documented in this region the lig highstand sequence correlates with varied eemian marine and paralic mis 5e deposits encountered along northern and western european siberian and additional shores apart from reliably dated sangamonian s florida coral reefs identification and dating of lig highstand deposits remain highly problematical in se atlantic shore terraces

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

geochemical evidence for african dust and volcanic ash inputs to terra rossa soils on carbonate reef terraces northern jamaica west indies abstract the origin of red or reddish brown clay rich terra rossa soils on limestone has been debated for decades a traditional qualitative explanation for their formation has been the accumulation of insoluble residues as the limestone is progressively dissolved over time however this mode of formation often requires unrealistic or impossible amounts of carbonate dissolution therefore where this mechanism is not viable and where local fluvial or colluvial inputs can be ruled out an external source or sources must be involved in soil formation on the north coast of the caribbean island of jamaica we studied a sequence of terra rossa soils developed on emergent limestones thought to be of quaternary age the soils become progressively thicker redder more fe and al rich and si poor with elevation furthermore although kaolinite is found in all the soils the highest and oldest soils also contain boehmite major and trace element geochemistry shows that the host limestones and local igneous rocks are not likely source materials for the soils other trace elements including the rare earth elements ree show that tephra from central american volcanoes is not a likely source either however trace element geochemistry shows that airborne dust from africa plus tephra from the lesser antilles island arc are possible source materials for the clay rich soils a third as yet unidentified source may also contribute to the soils we hypothesize that older more chemically mature jamaican bauxites may have had a similar origin the results add to the growing body of evidence of the importance of multiple parent materials including far traveled dust to soil genesis

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

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