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

history of stage 5 sea level in bermuda review with new evidence of a brief rise to present sea level during substage 5a abstract oxygen isotope substage 5e is represented by the devonshire formation in bermuda the occurrence of these coastal marine deposits to about 5 m indicates pleistocene sea level data in bermuda do not need tectonic corrections a few published u series coral dates suggest that a conglomerate spencer s point formation may have formed during substage 5c geologic mapping however indicates that the eolianite beneath the conglomerate is pre rather than post devonshire formation in age as was previously thought and the aminostratigraphy of marine sheels also confirms the correlation of the spencer s point and devonshire formations substages 5c and 5a are represented by the southampton formation large eolianites comprise the bulk of this formation they are onlapped by a few small younger marine 1 m and eolian deposits aminostratigraphy confirms that these late southampton age deposits are significantly younger than the devonshire formation and u series dates indicate a substage 5a age the setting of some of these deposits along a protected shoreline precludes discounting their position as anomalous due to large storms this evidence that sea level in bermuda was at about present datum late in substage 5a agrees with interpretations of neotyrrhenian deposits of mediterranean shorelines but not with inferences from the deep sea oxygen isotope record or with data from uplifted coral reefs

a uranium thorium dated late eemian or early midlandian organic deposit from near kilfenora between spa and fenit co kerry ireland this paper discusses the dating of stratigraphically important quaternary sequences from a site near fenit co kerry which have been the subject of debate since they were first described by mitchell in 1970 the overall stratigraphy of the quaternary deposits have been investigated and detailed analyses of the organic material carried out pollen from biogenic sediments have been analysed and samples of peat dated using the uranium thorium disequilibrium method the pollen assemblages match no others previously recorded in ireland and appear to represent a cool temperate phase following the last interglacial the uranium thorium dates of between 114000 and 123000 yr bp indicate that the deposit dates from oxygen isotope stage 5 possibly post dating the last temperate stage the eemian stage interglacial oxygen isotope substage 5e the dating of this deposit and the realisation that it is not penultimate temperate stage gortian in age invalidates much recent speculation on the age of the gortian interglacial

aminostratigraphy of quaternary shorelines in the mediterranean basin the age and correlation of shorelines around the mediterranean basin have been addressed by analyzing the extent of isoleucine epimerization aile ile ratio in protein preserved in molluscan fossils collected from raised marine deposits the taxodont genera glycymeris and arca were selected as the primary taxa for this study because of their simple shell structure reproducible aile ile ratios and ubiquitous occurrence direct comparison of aile ile ratios in associated mollusks allows correlation of disjunct marine deposits and relative dating of sequential marine units in nearby areas that have similar thermal histories the thermal gradient across the mediterranean basin is however sufficiently high that shells from isochronous shorelines have significantly higher ratios at warmer than at cooler localities absolute dating primarily u series dates on corals directly associated with molluscan samples provides an independent calibration of the amino acid data and compensates for dissimilar thermal histories aile ile ratios in shells from 46 marine units cluster into 5 discrete groups c e f g and k that are related to positive sea level events interglacials interstadials associated with odd numbered deep sea isotopic stages the most complete sequences are in southern italy where group c ratios in glycymeris that average 0 30 are associated with the neotyrrhenian a post last interglacial late stage 5 high sea level event group e ratios 0 38 are associated with classical eutyrrhenian deposits from which four u series coral dates 126 7 ka substantiate the correlation to isotope substage 5e group f ratios 0 50 are associated with u series coral and mollusk dates between 200 and 300 ka the deposits are tentatively correlated with stage 7 deposits that have group g ratios 0 58 are correlated with stage 9 shells from lower pleistocene marine deposits that have ratios between 1 0 and 1 2 group k constrain the ages of the younger groups an exponential decrease in the epimerization rate inhibits resolution of the older events aile ile ratios in last interglacial deposits are similar in the northern and central region of the study area but increase sharply in southern sicily north africa and crete similar to the modern thermal gradient a lacuna between group g and group k is similar to gaps identified in california and alaska suggesting generally lower interglacial sea levels between stage 11 and sometime before the brunhes matuyama boundary

regional uplift and local tectonic deformation recorded by the quaternary marine terraces on the ionian coast of northern calabria southern italy abstract the setting of a flight of marine terraces along a 65 km long section of the ionian coast of northern calabria is the result of the interaction between interglacial sea levels regional uplift and local fault related elevation changes seven terraces with corresponding palaeoshoreline angles at elevations ranging from 12 m to 420 m were recognised by aerial photo interpretation and field surveying the terraces were correlated to the oxygen isotope stages 1 5a 5c 5e 7 9 15 which correspond to the 7 81 102 124 215 330 and 600 ka highstands of the palaeosea level curve the 600 ka long regional ascent of the terraces took place at an average uplift rate of 0 67 mm yr this value slightly but progressively increases southward along the coastline the elevation of the strandlines is related to the activity of tectonic structures three cases were analysed allowing us 1 to recognise the height anomalies of the terraces on the sibari plain as the result of cumulated coseismic deformation caused by the normal castrovillari fault and on this basis calculate a minimum slip rate and a mean recurrence time for a single event of deformation 2 to exclude the presence of significant vertical deformations and consequently activity on the easternmost section of the normal pollino fault and 3 to hypothesise the presence of an hitherto unknown active fault responsible for the strong vertical displacements of the flight of terraces near the river avena finally we find the ratio of the rate of regional uplift to the average rates of local tectonic deformation to be 2 to 3 1

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

evaluation of tsunami risk from regional earthquakes at pisco peru we evaluate tsunami risk for the port city of pisco peru where major liquefied natural gas facilities are planned we use a compilation of instrumental and historical seismicity data to quantify the sources of six earthquakes that generated tsunamis resulting in minor inundation 1974 to catastrophic destruction 1687 1746 1868 in pisco for each of these case scenarios the seismic models are validated through hydrodynamic simulations using the most code which compute both flow depth on virtual offshore gauges located in pisco harbor and the distribution of runup in the port and along the nearby beach space time histories of major earthquakes along central and southern peru are used to estimate recurrence times of tsunamigenic earthquakes we conclude that pisco can expect a metric tsunami capable of inflicting substantial damage every 53 years and a dekametric tsunami resulting in catastrophic destruction of infrastructures every 140 years the last such event occurred 138 years ago an important result of our study is that total destruction of the city of pisco during the famous 1868 arica tsunami requires an earthquake rupture straddling the nazca ridge which thus constitutes at best an imperfect barrier for the propagation of rupture during megathrust events this gives a truly gigantic size to the 1868 arica earthquake with a probable seismic moment reaching 1030 dyne cm

south carolina interglacial sites and stage 5 sea levels abstract amino acid and other studies have been made on the 30 km pleistocene sections of the intracoastal waterway between myrtle beach and little river south carolina our ratios differentiate the long established waccamaw oldest canepatch and socastee formations the ratios from the four laboratories that have worked in this area agree very well and apparent conflicts with u series dates may merely reflect an abundance of reworked corals our amino acid correlations with u series coral dates in south carolina bermuda and the mediterranean all argue that the classical canepatch and its horry clay date from isotope stage 5e and not as has been implied from stage 7 9 11 or 13 excavations and erosion have increased position fixing problems along the waterway and canepatch amino acid ratios and u series dates 460 000 100 000 yr b p at icw5 may be from an older unit the canepatch shows the double marine transgression visible in many stage 5e deposits pollen shows that the second transgression occurred late in the interglaciation and stratigraphic studies show that it reached 14 m it therefore fits very well antarctic ice surge models of stage 5 sea level and climate the socastee adds to the evidence for one or more sea levels above 0 m late in stage 5

revision of the late pleistocene stratigraphy of bermuda the quaternary stratigraphy of bermuda is one of the world s most complete sedimentary records of interglacial highstands representing at least the past million years yet in terms of the last interglacial rocky bay formation marine isotope substage mis 5e only scanty deposits are preserved in contrast mis 7 generally regarded as a diminutive interglaciation exposes widespread emergent subtidal deposits of the belmont formation indicating a prolonged sea level highstand at ca 2 5 0 3 m this belmont paradox has prompted a reexamination of the geology of key sites along the south shore of bermuda this revision of the late quaternary stratigraphy of bermuda is based on geological field observations primarily the questionable origin of red soil like deposits it is concluded here that there is no physical evidence of the exposure of the upper belmont surface for a full glacial cycle 70 100 ka and that interbedded reddish soil like lenticular deposits are the result of colluvial activity during mid mis 5e reexamination of previously published uranium series u th ages indicates that several 3 m notches contain a mix of ca 125 ka and older coral ages contrary to previous works this study favors an early mis 5e interpretation of the coral ages from the 2 5 m belmont shoreline which is further supported by amino acid racemization aar ratios on whole rock poecilozonites glycymeris and brachiodontes samples from shore and notch deposits an updated aar kinetic model demonstrates that the bulk of epimerization occurred during warm interglacial intervals between 130 and 80 ka and the last 10 ka of the holocene this revised stratigraphy of bermuda now falls into accordance with a more general view of middle and late pleistocene sea level history

boulder deposits from large waves during the last interglaciation on north eleuthera island bahamas abstract seven boulders measuring 100 to 1000 m 3 are scattered along the coastal ridge of north eleuthera some are situated on ridge crests up to 20 m above present sea level the boulders were probably deposited during oxygen isotope substage 5e or 5d as shown by their stratigraphic setting and by amino acid racemization ratios d alloisoleucine l isoleucine ratios were determined for land snails and oolite of both marine and eolian origin was associated with the boulders like the boulders the probable source rocks exposed in the adjacent cliffs are composed of marine and eolian limestone of oolitic and peloidal composition the source beds are correlated with stage 9 or 11 the largest boulder is about 10 times the size of the largest holocene ones moved by waves in the area tsunamis are a reasonable possibility as a transporting mechanism of the pleistocene boulders however if deposited instead by storms during the last interglaciation the storms were of much greater intensity than those occurring in the region during the late holocene

low uplift rates and terrace reoccupation inferred from mollusk aminostratigraphy coquimbo bay area chile abstract mollusk aminostratigraphy of quaternary marine terrace sediments at coquimbo bay chile combined with recently available electron spin resonance esr ages necessitates revision of the northern chilean relative sea level and terrace chronology protothaca and mulinia d alloisoleucine l isoleucine values define four aminozones which are consistent with available esr ages terrace reoccupation during successive high sea level stands is inferred on the basis of litho and aminostratigraphically defined unconformities in terrace sediments esr data and a nonlinear kinetic racemization model give approximate numerical ages for the aminozones and thus yield estimates of net uplift rates these rates averaged over intervals of one to several hundred thousand years have ranged from less than 0 1 m 1000 yr to no more than 0 2 m 1000 yr such slow uplift is the cause of terrace reoccupation as the amount of uplift between successive glacioeustatic high sea level stands is frequently not sufficient to isolate an earlier formed abrasion platform from rising sea level during a subsequent high stand

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

late quaternary uplift rates of marine terraces on the pacific coast of north america southern oregon to baja california sur abstract marine terraces are common landforms along the pacific coast of north america from southern oregon to southern baja california we report 60 new uranium series ages of marine terrace corals hydrocorals and other fossils terraces representing the ca 80 ka and ca 125 ka high stands of sea are the most common along the pacific coast and we have used these ages along with terrace shoreline angle elevations and paleo sea level estimates to calculate late quaternary uplift rates uplift rates in the forearc region of the cascadia subduction zone range from 0 45 1 08 m kyr farther south along most of the coast west of the san andreas fault zone uplift rates range from 0 15 0 35 m kyr but some areas have significantly higher rates of uplift and others have apparently experienced little or no uplift in the last 125 ka in baja california sur west of the east pacific rise little or no uplift has occurred during the late quaternary on average the magnitude of rates of uplift for the tectonic regimes is as follows cascadia subduction zone san andreas fault zone region east pacific rise region

origin of bermuda s clay rich quaternary paleosols and their paleoclimatic significance red clayey paleosols that are chiefly the product of aerosolic dust deposition are interbedded in the quaternary carbonate formations of the bermuda oceanic island system these paleosols provide a basis for reconstructing quaternary atmospheric circulation patterns in the northwestern atlantic geochemical analyses were performed on representative paleosol samples to identify their parent dust source fine grained fractions were analyzed by energy dispersive x ray fluorescence to determine trace element zr y la ti and nb concentrations and to derive geochemical signatures based on immobile element ratios these ratios were compared with geochemical signatures determined for three possible sources of airborne dust 1 great plains loess 2 mississippi river valley loess and 3 saharan dust the zr y and zr la ratios provided the clearest distinction between the hypothesized dust sources the low ratios in the paleosol b horizons most closely resemble saharan dust in the 2 m size class fraction contributions from the two north american loessial source areas could not be clearly detected thus bermuda paleosols have a predominantly saharan aerosolic dust signature saharan dust deposition on bermuda during successive quaternary glacial periods is consistent with patterns of general circulation models which indicate that during glacial maxima the northeast summer trade winds were stronger than at present and reached latitudes higher than 30on despite lower than present sea surface temperatures in the north atlantic

oxygen isotopes and sea level from the time that detailed oxygen isotope records derived from foraminifera living in the constant temperature environment of the abyssal ocean became available there has been a discrepancy between the ice volume record that these records imply and that derived from the altitude of dated coral terraces around the world here we re examine the data and conclude that the temperature of the abyssal ocean has been an actively varying component of the climate system

sequential evolution and diagenesis of pleistocene coral reefs south sinai egypt abstract the uplifted pleistocene coral reefs in south sinai represent two major depositional sequences they generally form two morphological terraces which locally are tilted and offset by still active faulting the major reef sequences are composed of several small scale sequences corals grew rapidly when accommodation space was created by eustatic sea level rise or fault block subsidence as the accommodation decreased coral rubble and siliciclastic sands prograded over reefal and lagoonal sediments thus creating a shallowing upward sequence terrigenous input was further stimulated by a more humid climate during interglacial times 230 th 234 u dating places the older reef cycle between 350 000 and 270 000 years b p which corresponds to the interglacial period of isotope stage 9 the younger reef cycle has been dated between 140 000 and 60 000 years b p isotope stage 5 an intermediate relic sequence found in only one outcrop can be attributed to isotope stage 7 correlation of the small scale sequences is difficult age dating is not precise enough and local tectonic activity in many cases overruled the smaller eustatic fluctuations the younger reef sequence commonly exhibits marine cements whereas the older sequence was exposed to freshwater dissolution and cementation an important feature is the locally pervasive dolomitization especially of the older reef oxygen and carbon isotope values suggest that the dolomite formed in a seawater dominated mixing zone multiple phases of dissolution cementation and dolomitization point to a very complex diagenetic history

pliocene pleistocene coastal events and history along the western margin of australia coastal deposits along the western coastal margin of australia a region of relative tectonic stability record plio pleistocene events and processes affecting the inner shelf and adjacent hinterland tectonic deformation of these deposits is more apparent in the carnarvon basin and rather less so in the perth basin the most complete record comes from the perth basin where units of pliocene and pleistocene ages are well represented in the perth basin the predominantly siliciclastic yoganup formation ascot formation and bassendean sand represent a complex of shoreline inner shelf and regressive dune facies equivalents the deposition of which began at an undetermined stage of the pliocene through to the early pleistocene the deposition of this sequence closed with a major regression and significant faunal extinction bioclastic carbonates characterize the middle and late pleistocene of the perth and carnarvon basins fossil assemblages include a distinct subtropical element unknown from the ascot formation and suggesting a strengthening of the leeuwin current the estuarine arcoid bivalve anadara trapezia characterizes assemblages of oxygen isotope stages 5 and 7 in the perth and carnarvon basins where it is now extinct deposits of substage 5e perth basin also record a southerly expansion of warm water corals and other fauna consistent with shelf temperatures warmer than present new uranium series ages on corals from marine sequences of the tantabiddi member of the bundera calcarenite of the western cape range are consistent with the double peak hypothesis for levels of substage 5e but the evidence remains less than conclusive initial uranium series dates from the bibra and dampier formations of shark bay indicate that both derive from the late pleistocene these numerical ages contradict previous interpretations of relative ages obtained from field studies the age relationship of the units requires further investigation

sea level controls on carbonate beaches and coastal dunes eolianite lessons from pleistocene bermuda 2015 geological society of america coastal dune accumulations at locations around the world have formed during sea level highstands rising sea levels falling sea levels and fluctuating sea levels initially episodes of maximum pleistocene dune activity in bermuda which is the type location for eolianite were correlated with glacio eustatic regressions this model had been abandoned by the 1970s in favor of a rising sea level model for bermuda s north shore and autogenic sediment supply model for the south shore we report the results of a detailed investigation of the intercalated mid late pleistocene beach and coastal dune deposits on the islands of bermuda and we test the existing models for these deposits we contend that the north shore model is invalidated by past misidentification of eoliandeposits as transgressive beach deposits on the south shore facies analysis of the marine isotope stage 7 mis 7 belmont formation reveals that coastal deposition was divided into two phases s1 which includes foreshore and shoreface progradation is predominantly marine and coincided with rising relative sea level s2 which commenced with protosol development on top of the marine section prior to burial by advancing dunes is nonmarine we conclude that the two successions s1 and s2 resulted from forcing by glacio hydro isostatic relative sea level change spanning a highstand rising and then falling rather than from transgressive or autogenic processes the finding that in bermuda the construction of protective coastal dunes depends on a falling relative sea level has potential implications for many vulnerable shorelines that face rising relative sea levels associated with climate change

integrated late quaternary chronostratigraphy for san salvador island bahamas patterns and trends of morphological change in the land snail cerion abstract reconstructing the phylogeny and biogeography of the caribbean land snail cerion requires a robust stratigraphic and chronological framework to this end we have determined the stratigraphic succession on san salvador a bahamian island with a rich fossil and modern cerion fauna a primary purpose of this paper is to independently verify this succession through whole rock and cerion aminostratigraphies and ams 14c based age models over 150 individual cerion shells were age ranked from 140 ka to modern using stratigraphic position and reverse phase hplc rpc amino acid racemization which was sufficiently sensitive to resolve stratigraphic subunits within the holocene and late pleistocene a secondary purpose of this paper is to assess broad changes in the gross morphology height width of supersets of cerion from age ranked lots spanning this 140 kyr chronostratigraphy through each of the three interglacial sequences i e marine isotope stages 5e 5a and 1 between sample trends in mean gross morphology often greatly exceed within sample variances 1 live collected cerion exhibit a range in gross morphology that nearly encompasses that of the entire fossil sequence a trend of increasing gross shell size characterizes each of the interglacial phases with a major step decrease between marine isotope stages 5a and 1 while between unit variation is often great in cerion from ssi within unit variation appears unimodal through the record

revealing the deep structure and rupture plane of the 2010 maule chile earthquake mw 8 8 using wide angle seismic data the 27 february 2010 maule earthquake mw 8 8 ruptured 400 km of the nazca south america plate boundary and caused hundreds of fatalities and billions of dollars in material losses here we present constraints on the fore arc structure and subduction zone of the rupture area derived from seismic refraction and wide angle data the results show a wedge shaped body 40 km wide with typical sedimentary velocities interpreted as a frontal accretionary prism fap landward of the imaged fap the velocity model shows an abrupt velocity contrast suggesting a lithological change which is interpreted as the contact between the fap and the paleo accretionary prism backstop the backstop location is coincident with the seaward limit of the aftershocks defining the updip limit of the co seismic rupture and seismogenic zone furthermore the seaward limit of the aftershocks coincides with the location of the shelf break in the entire earthquake rupture area 33 s 38 5 s which is interpreted as the location of the backstop along the margin published seismic profiles at the northern and southern limit of the rupture area also show the presence of a strong horizontal velocity gradient seismic backstop at a distance of 30 km from the deformation front the seismic wide angle reflections from the top of the subducting oceanic crust constrain the location of the plate boundary offshore dipping at 10 the projection of the epicenter of the maule earthquake onto our derived interplate boundary yielded a hypocenter around 20 km depth this implies that this earthquake nucleated somewhere in the middle of the seismogenic zone neither at its updip nor at its downdip limit

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

global sea level stratigraphy an appraisal abstract although pleistocene sea level concepts were first developed in the mediterranean basin research has been revolutionized during the past 15 years by massive dating programs applied in other world areas reappraisal of four key sequences nonetheless shows that the chronometric framework is imperfect as a result available paleosea level traces continue to depend on deep sea stratigraphy for confirmation rather than the reverse they do not provide independent support for the milankovitch radiation cycles nor do they invite deductive hypothetical dating by means of such astronomical reconstructions inferred initial sea levels based on uplift assumptions or 18 o determinations on coral and mollusca show considerable divergence but broadly agree that sea levels assigned to isotope stages 5a and 5c were lower than today systematic studies should be expanded in environments that allow lithostratigraphic resolution of interdigitated marine and continental sediments meticulously complemented by biostratigraphic work direct information on the complexity and significance of regressional hemicycles helps place sea level stages recorded by transgressive facies into a multidimensional context essential for comprehensive interpretation

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

shelf resonance and impact of near field tsunami generated by the 2010 chile earthquake 1 the 2010 chile earthquake of mw 8 8 generated a destructive tsunami in the near field that resulted in warnings across the pacific numerical modeling shows trapping and amplification of the energy over the continental shelf and slope a spectral analysis of the computed surface elevation reveals resonance oscillations with periods up to 129 min along the central chile coast the temporal and spectral data provides an explanation for the long period waves recorded by dart buoys and the prolonged wave activities and belated impacts reported by residents and survey teams the present study of the 2010 chile tsunami together with those of the 2006 kuril and 2009 samoa tsunamis has directly associated shelf resonance with impacts on insular and continental coasts and provided a tool to identify at risk localities in tsunami hazard assessment

mineralogical evidence for a local volcanic origin of the parent material of bermuda quaternary paleosols the alternation of carbonate deposits and paleosols compose the emerged part of the bermuda archipelago the pedological units present a complex and diversified mineralogy former studies demonstrated that the paleosols are not primarily a product of the unique dissolution of the surrounding carbonates but contain a massive input of allochthonous non carbonate detrital material researchers during more than the past three decades have attributed this flux of insoluble residues ir to saharan dusts we carried out systematic field and mineralogical analyses on the quaternary paleosols from the bermuda archipelago their mineralogical assemblage predominantly includes carbonates clay minerals kaolinite chlorite and chlorite vermiculite phosphates and aluminium and iron oxides hydroxides this assemblage is strikingly close to the mineralogy of the weathered volcanic substrate of bermuda but noticeably different from the mineralogy of saharan dust moreover we found volcanic lithoclasts in numerous paleosol profiles all over the archipelago and in all the recorded time intervals we thus consider the volcanic seamount underlying bermuda as the main source of non carbonate minerals detected in the paleosols this hypothesis further resolves the anomalous maturity of bermudan paleosols compared to their southern counterparts in the bahamas and barbados

source discriminants for near field tsunamis summary we present numerical simulations of tsunami run up in the near field for a data set of 72 models of sources involving both seismic dislocations and landslides by varying one by one the parameters describing the source and the receiving beach we are able to separate their individual influence on the amplitude and distribution of run up which we characterize by forming several dimensionless parameters principally the ratio i 2 of its maximum amplitude to its lateral extent along the beach we find that i 2 remains less than 10 4 for seismic dislocation sources but is greater than this threshold for all physically realistic models of underwater landslides thus it can be used as a discriminant for the nature of the source of a near field tsunami for seismic dislocations we also consider the ratio i 1 of maximum run up to seismic slip on the fault plane and validate numerically the previously suggested rule of thumb that this ratio cannot be much greater than 1 in the case of underwater landslides we show that the distribution of near field run up is primarily controlled by the 2 d wall of water displaced on the ocean surface as an initial condition to the simulation and is practically independent of its extension in the third dimension perpendicular to the beach we apply this approach to nine profiles of tsunami run up obtained experimentally during recent field surveys and show that our method successfully identifies the 1998 papua new guinea tsunami as having been generated by an underwater landslide thus confirming the results of shipboard and hydroacoustic investigations it also strongly suggests a similar mechanism for the generation of the near field aleutian tsunami of 1946 april 1

historical sea level changes and effects on the coasts of sorrento peninsula gulf of naples new constrains from recent geoarchaeological investigations abstract this paper describes the results of a multidisciplinary study of four geoarchaeological sites on the sorrento peninsula coast italy where the submerged ruins of roman buildings have enabled the ancient position of both the sea level and the coastline to be reconstructed the results highlight that the sea level in roman times deduced from the submersion measurement of archaeological markers did not exceed 1 2 m 0 30 m except for seiano whose submerged remains and surrounding area were heavily damaged by extreme events following the 79 ce vesuvius eruption the comparison of these results with the eustatic sea level curve in roman times together with the submersion of the tectonically stable site on the tyrrhenian coast of italy torre astura with a well preserved roman fishpond demonstrate that the sorrento peninsula has been tectonically stable over the last two millennia this behaviour started many thousands of years ago not later than the last interglacial while the nearby plain of pompeii and probably the bottom of the adjacent gulf of naples have been subsiding at rates of 1 or more mm per year in the same time span two of the investigated coastal sectors capo di sorrento and punta campanella have not suffered any significant changes because their sea cliffs are cut in hard limestone the tufa sea cliff of the sorrento plain on the other hand has been retreating by several metres on the marina di equa seiano alluvial coastal plain which suffered the effects of the 79 ce eruption the debris and hyperconcentrated flow produced a progradation of 200 m which has been totally dismantled over three centuries

late stage 5 glacio isostatic sea in the st lawrence valley canada and united states abstract although post glacial marine sediments of late wisconsinan and early holocene age are common in eastern canada and the northeastern united states remnants of older pleistocene marine sediments are scarce a fossiliferous marine clay that predates the classical wisconsinan was recently discovered in the st lawrence valley a dominantly estuarine environment is inferred from the geochemistry of the shells 18 o 7 1 and from benthic foraminifer and ostracode assemblages the clay indicates a marine invasion cartier sea shallower and probably shorter than that during the upper late wisconsinan champlain sea episode 12 000 9 500 yr b p the pollen content shows that regional vegetation during the marine episode began as open tundra then became a betula and alnus crispa forest reached a climatic optimum with quercus corylus and abies and concluded as a pinus picea boreal forest a corrected infrared stimulated luminescence age of 98 000 9000 yr is compatible with the epimerization ratio of shells the cartier sea resulted from a post glacial glacio isostatic marine invasion in the st lawrence lowlands it probably occurred during late stage 5 and is tentatively assigned to the transition of oxygen isotope substages 5b 5a this marine episode dates to stage 5 of the preceding continental glacier which extended to middle latitudes in ne america

glacial terminations in the oxygen isotope record of deep sea cores hypothesis of massive antarctic ice shelf destruction abstract glacial terminations i and ii in the deep sea core foraminiferal oxygen isotope ratios though not similar in form are each characterized by a short interval of about 3 ka during which a large negative change occurred in the ratios after correcting for temperature effects we estimate that each change was equivalent to a glacial disintegration capable of causing a 50 60 m eustatic sea level rise in the termination i interval 16 13 ka b p the estimated equivalent sea level rise is much larger than that suggested by the best evidence of deglacial ice loss from the laurentide ice sheet which is thought to dominate pleistocene glacial ice volume changes moreover in termination ii about 125 ka b p the estimated equivalent sea level rise is much larger than that inferred from the stratigraphy of coral reefs and beaches on new guinea and other locations which suggests quite high sea levels for 10 ka prior to this termination to reconcile these severely conflicting lines of evidence we propose that the rapid negative isotope ratio changes were largely caused by the disintegration of massive floating antarctic ice shelves which masqueraded as land ice in the oceanic isotope ratios but which contributed no sea level change we propose that such shelves were formed when oceanic circulation changes in the north atlantic under glacial conditions greatly reduced the formation of relatively warmer north atlantic deep water and its injection into circumpolar antarctic regions and that the shelves disintegrated rapidly with the resumption of large scale formation of this deep water and its input into the antarctic we find that high sea levels in the 125 135 ka b p interval prior to termination ii which imply very little northern ice then are well supported by dated coral reef stratigraphy although these ages were not accepted by the climap study of the last interglacial ocean minimal northern ice volumes at that time imply that strong milankovitch summer insolation is not always required for northern deglaciation a promising additional deglacial mechanism is the prolonged viscous depression of the crust beneath the laurentide ice sheet combined with atmospheric oceanic circulation factors

teleseismic inversion for rupture process of the 27 february 2010 chile mw 8 8 earthquake the 27 february 2010 chile m w 8 8 earthquake is the fifth largest earthquake to strike during the age of seismological instrumentation the faulting geometry slip distribution seismic moment and moment rate function are estimated from broadband teleseismic p sh and rayleigh wave signals we explore some of the trade offs in the rupture process estimation due to model parameterizations limited teleseismic sampling of seismic phase velocities and uncertainty in fault geometry the average slip over the 81 500 km 2 rupture area is about 5 m with slip concentrations down dip up dip and southwest and up dip and north of the hypocenter relatively little slip occurred up dip offshore of the hypocenter the average rupture velocity is 2 0 2 5 km s

controls on interior west antarctic ice sheet elevations inferences from geologic constraints and ice sheet modeling abstract knowledge of the west antarctic ice sheet wais response to past sea level and climate forcing is necessary to predict its response to warmer temperatures in the future the timing and extent of past interior wais elevation changes provides insight to wais behavior and constraints for ice sheet models constraints prior to the last glacial maximum lgm however are rare surface exposure ages of glacial erratics near the wais divide at mt waesche in marie byrd land and at the ohio range in the transantarctic mountains range from 10 ka to 500 ka without a dependence on elevation the probability distribution functions pdf of the exposure ages at both locations are remarkably similar during the last glaciation maximum interior ice elevations as recorded by moraines and erratics were reached between 10 ka and 12 ka however most exposure ages are older than the lgm and cluster around 40 ka and 80 ka the peak in the exposure age distributions at 40 ka includes ages of alpine moraine boulders at mercer ridge in the ohio range comparison of the pdf of exposures ages from the ohio range and mt waesche with the temperature record from the fuji dome ice core indicates that the youngest peak in the exposure age distributions corresponds to the abrupt warming during the last glacial termination a prominent peak in the ohio range pdf corresponds to the penultimate termination stage 5e during the intervening glacial period there is not a consistent relationship between the peaks in the pdf at each location and temperature a combined ice sheet ice shelf model with forcing scaled to marine 18 o predicts that interior wais elevations near the ice divide have varied 300 m over the last glacial cycle peaks in the pdf correspond to model highstands over the last 200 ka in the simulated elevation history maximum ice elevations at ohio range 100 m and mt waesche 60 m occur at 10 ka in agreement with observations from these sites during collapse of the marine portion of the wais ice elevations at ohio range and mt waesche are drawn down at least 200 m below the present ice elevation the good correspondence between the model results and observations at both the ohio range and mt waesche supports the conclusion that interior wais highstands do not occur during glacial maximums rather the highstands are controlled primarily by increased accumulation during temperature maximums that occur early in the interglacials interior down draw events follow highstands resulting from the arrival of a wave of thinning triggered by retreat of the wais grounding line coupled with decreasing accumulation rates

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

anomalous mis 7 sea level recorded on bermuda three new u series ages from coral fragments found in the belmont formation of bermuda fall in a range of 198 ka to 196 ka these late mis 7 ages are consistent with those of 201 ka and 199 ka measured in a previous study the disputed interpretation of the belmont formation as a unit that is allostratigraphically distinct from subsequent mis 5e deposits of the rocky bay formation is vindicated by a minimum age of 196 3 ka for the total of 6 coral fragments it has yielded emergent marine deposits of the belmont formation include sedimentary lithofacies that are considered to be reliable relative sea level indicators prominent among these is a facies representing the beach step a feature that develops sub tidally directly at the base of the swash zone from this facies and others preserved along 6 km of belmont formation coastal exposure it is concluded that mis 7 relative mean sea level reached 4 5 m and likely peaked at or above 6 0 m relative to present sea level at bermuda lower mis 7 sea level positions that are evidenced and that have been quoted in the past are considered transitory positions not maxima the mis 7 sea level elevations on bermuda reconstructed in this study are above the majority of those reported from elsewhere in the world this challenges the long standing notion of bermuda as a vertically stable tide gauge but is consistent with glacio hydroisostatic models which predict land mass subsidence at intermediate field sites such as bermuda at the end of long interglacials however because of evidence of instability at bermuda in the form of seismic activity and faulting which require further investigation judgement is reserved on the global implications of this palaeo sea level anomaly

oxygen isotopes sea level changes and the temperature history of a coral reef environment in new guinea over the last 105 years abstract coral reef terraces consisting of an upward succession of fringing and barrier reef types are preserved on land along the raising coast of huon peninsula new guinea seven coral reef units i vii from the coast landwards spaced at about 20 kyr interval provide a rather complete record of sea levels oxygen isotopes and temperature of teh surface tropical ocean over the duration of the high sea level events of the last glacial cycle the systematic sampling of the coral reefs was restricted to the massive tridacna gigas species the giant clam which are about 0 7 0 enriched in 18o relative to calcite equilibrium value and the presence of symbionts seems to have no effect on the 18o of their aragonitic skeleton sea levels rose rapidly to 5 6 5 m above present during the last interglacial which on stratigraphic grounds and 18o compositions can be separated into an early phase whose 18o is similar to modern reef viia dated at 138 kyr and a late phase that is 0 6 0 heavier reef viib dated at 118 kyr fringing reefs vi v iv iii and ii record short lived high sea levels stands at 107 85 60 45 to 40 and 31 kyr respectively that stopped short of the present sea level 12 19 28 32 to 42 m the general decline of the high sea level stands corresponds to an average 18o enrichment of 1 7 0 measured between the early interstadials of isotope stage 5 vi and v and the late interstadials of isotope stage 3 iv iiia iiib and ii the maximum 18o enrichment of 1 7 0 relative to present was registered during a regressive phase of reef iiia stratigraphic evidence indicates that sea level lows in the range of 37 to 55 m below present have occurred in between the high sea level stands but those are unlikely to represent the lowest sea levels of the last glacial cycle sea levels and 18o ddta pair offer important clues regarding the partitioning of ice volume and temperature in 18o records the results suggest that the ice volume effect accounts for the observed 18o changes during the early interstadial culminations but only for 29 46 during the late interstadial culminations sea water cooling beyond the threshold limit of coral reef growth 18 c did not occur during the last glacial cycle the temperature of the surface tropical ocean was similar to present during the early interstadials of isotope stage 5 and cooler by 3 c below present during the later interstadials of isotope stage 3

climate change dynamics in northern eurasia over the last 200 ka evidence from mollusc based esr chronostratigraphy and vegetation successions of the loess palaeosol records abstract the time span of the past 200 ka has been marked by many large scale global and regional climate changes between warmer and cooler conditions as is usually the case when studying the past palaeoenvironmental data become scarcer with increasing age therefore every detailed palaeoenvironmental record may be of special interest to quaternary geologists in terms of palaeoenvironmental reconstructions correlations and general stratigraphy of the quaternary in this paper we present a long palynological record of terrestrial flora and an esr dated marine record of global scale climatic variation obtained from a loess palaeosol sequence in the east european plain and continental margin of northern eurasia for the time span starting from the penultimate glacial period correlating with marine isotope stage mis 6 these records show that in combination they have a potential of assigning warm cold climate related deposits to the chronostratigraphically organised sequence of the late pleistocene palaeoenvironmental events

a rapid estimation of near field tsunami runup many efforts have been made to quickly estimate the maximum runup height of tsunamis associated with large earthquakes this is a difficult task because of the time it takes to construct an accurate tsunami model using real time data from the source it is possible to construct a database of potential seismic sources and their corresponding tsunami a priori however such models are generally based on uniform slip distributions and thus oversimplify the knowledge of the earthquake source here we show how to predict tsunami runup from any seismic source model using an analytic solution that is specifically designed for subduction zones with a well defined geometry i e chile japan nicaragua and alaska the main idea of this work is to provide a tool for emergency response trading off accuracy for speed the solutions we present for large earthquakes appear promising here runup models are computed for the following the 1992 mw 7 7 nicaragua earthquake the 2001 mw 8 4 peru earthquake the 2003 mw 8 3 hokkaido earthquake the 2007 mw 8 1 peru earthquake the 2010 mw 8 8 maule earthquake the 2011 mw 9 0 tohoku earthquake and the recent 2014 mw 8 2 iquique earthquake the maximum runup estimations are consistent with measurements made inland after each event with a peak of 9 m for nicaragua 8 m for peru 2001 32 m for maule 41 m for tohoku and 4 1 m for iquique considering recent advances made in the analysis of real time gps data and the ability to rapidly resolve the finiteness of a large earthquake close to existing gps networks it will be possible in the near future to perform these calculations within the first minutes after the occurrence of similar events thus such calculations will provide faster runup information than is available from existing uniform slip seismic source databases or past events of premodeled seismic sources

pre sangamonian eolianites in the bahamas new evidence from eleuthera island abstract the present study provides new insight into the quaternary stratigraphy of the bahamas refining the stratigraphic record of tectonically stable carbonate islands such as the bahamas is important for improving our perception of eustatic and climatic variations during this time interval two key sections located 15 km apart in the northern portion of eleuthera display three vertically stacked rock units 1 a basal unit consisting of up to four eolianites separated by paleosols 2 intermediate oolitic deposits showing beach facies at 6 m and 3 an upper bioclastic eolianite overlain by a thick calcrete the occurrence of beach facies at an elevation of 6 m above msl suggests an early sangamonian age isotopic substage 5e for the intermediate oolitic deposits because of its position below a thick calcrete the upper unit was more likely formed during a later highstand of the sangamonian substage 5c or 5a rather than during the holocene it follows that the basal unit clearly predates the last interglacial this new evidence from eleuthera shows that pre sangamonian rocks may be more extensive in the bahamas archipelago than previously thought it also emphasizes the widespread occurrence of bioclastic limestones in an area often considered as being entirely composed of oolites

eustatic sea level and climate changes over the last 600 ka as derived from mollusc based esr chronostratigraphy and pollen evidence in northern eurasia we reconstruct and correlate palaeoclimatic events and deposits from shelf glacial periglacial and extraglacial zones of northern eurasia over the last 600 000 years the chronostratigraphical correlation of identified palaeoenvironmental and sealevel events and corresponding horizons is based on electron spin resonance esr analysis of subfossil mollusc skeletal remains from marine freshwater and acheulian bearing cave site deposits over 230 shell samples from more than 40 sites along the continental margin of eurasian north in the black and caspian sea basins and terrestrial shells from a lower palaeolithic cavesite in the northern caucasus were dated via esr to produce a late quaternary geochronology the pleistocene composite section of the loess palaeosoil formation includes two reference sections likhvin and arapovichi from the centre of the easteuropean plain the palyno chronostratigraphic record is interpreted as the product of six warm climate high sea level events including the current interglacial and six glacial events they are presented either as complete climatic rhythms of glacial and interglacial rank or by considerable portions of climatic phytocoenotic phases constituents of the rhythm the full interglacial conditions are centred at about 580 400 310 220 and between 145 70 calendar ka a broad correspondence between long palynological sequence directly esr dated warm climate related events and other palaeoenvironmental records described in the literature has been noted for 11 upper oxygen isotope stages 11 to 1 the results obtained in this study exemplify the potential of integrated chrono climatostratigraphic sequences in linking marine and terrestrial palaeoclimate records that may eventually span the whole brunhes chron d 2002 elsevier science b v all rights reserved

aminostratigraphy of european marine interglacial deposits molluscan fossils collected from shallow water marine sediment across nw europe and nearby arctic regions have been analysed for the extent of isoleucine epimerization dl ratio in indigenous protein residues the dl ratios confirm that essentially all classical eemian sites from nw europe are of the same age and are correlative with the type locality near amersfoort in the netherlands shells from interglacial marine sediment beneath the type weichselian till in poland also correlate with the type eemian site dl ratios in holsteinian marine shells 0 29 are substantially higher than in their eemian counterparts 0 17 late cromerian shells yield even higher ratios 0 46 dl ratios in late glacial shells 0 06 and middle weichselian shells 0 09 permit differentiation from modern 0 01 and last interglacial material based on the position of the matuyama brunhes boundary and the differences in dl ratios the eemian must correlate with isotope substage 5e whereas the holsteinian is most likely substage 7c possibly stage 9 but certainly younger than stage 11 intra saalian warm periods may be terrestrial equivalents of the younger substages of stage 7 extensive pre eemian marine sediments along the sw coast of denmark previously correlated with the holsteinian are shown to be of late cromerian age the underlying till there is the first widespread evidence of a pre elsterian till in nw europe dl ratios in molluscs from last interglacial sites along the arctic coast of the ussr the arctic islands and eastern greenland are substantially lower than in their european counterparts due to their low thermal histories the combined mid and high latitude data are used to develop a predictive model for the expected dl ratio in any of several moderate epimerization rate taxa for last interglacial sites with mean temperatures between 20 and 15 c not all sites could be unambiguously assigned to an established interglacial the fjosanger norway and margareteberg sweden sites previously thought to be eemian yield dl ratios higher than in secure nearby eemian material it is yet unresolved whether these are aberrant sites or if they predate the last interglacial in situ shoreline deposits encountered in borings in sw belgium and in exposures on the belgium coastal plain contain molluscs that yield dl ratios intermediate between secure eemian and late weichselian ratios raising the possibility that a late stage 5 high sea level event attained near modern levels in the southern north sea basin resolution of these uncertainties is the focus of future work

dating quaternary raised coral terraces along the saudi arabian red sea coast abstract late pleistocene raised coral reef terraces form extensive outcrops up to 5 km wide along the saudi coast porites coral were dated using u th while clastic sediment from jeddah was dated using thermoluminescence the pooled mean age for the coral samples is 121 5 0 2 ka suggesting mis 5e even for the uplifted 16 20 m high terrace in the north at haql in jeddah the mis 5e back reef succession is overlain by fluvial sediment that gave a tl age of 66 13 ka the structure and faunal composition of the coral terraces suggests that they accumulated in broad shallow embayments following the last interglacial transgression the consistent elevation of these terraces suggests that the central and southern saudi coast has been tectonically stable for at least the past 125 000 years and the coral reef terraces at 3 5 5 5 m elevation are consistent with the mis 5e sea level high stand that peaked at 6 9 m above present sea level the saudi coastal coral terrace north of duba shows progressive uplift to 16 20 m near haql since 108 120 ka as a result of ongoing transform faulting in the gulf of aqaba

a theoretical model of tsunami runup in chile based on a simple bathymetry mauricio a fuentes 1 2 javier a ruiz1 and armando cisternas1 3 1department of geophysics faculty of physical and mathematical sciences university of chile santiago chile e mail mfuentes dim uchile cl 2department of mathematical engineering faculty of physical and mathematical sciences university of chile santiago chile 3institut de physique du globe university of strasbourg strasbourg france

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

stratigraphy and geochronology of pitfall accumulations in caves and fissures bermuda abstract deep fractures fissures and avens skylights in limestone cave roofs create natural traps for sediments and biota fissures fill quickly with surface sediment and organisms soon after opening debris cones are formed as materials fall wash or drift on air through openings in cave skylights such deposits in admiral s and grand canyon cave bermuda contain distinct beds and are composed of mixtures of sediment and charcoal together with fossils of land snails crabs birds reptiles and bats the pitfall accumulations were periodically sealed over by calcite flowstone a stratigraphic record of surface activity and fauna through both glacial and interglacial periods has been preserved the succession also provides an ideal setting in which to compare several geochronological methods calibrated 14 c ages on charcoal and shells provide dated horizons at 1600 12 800 and about 35 000 14 c yr bp thermal ionization mass spectrometric tims ages on several flowstone layers constrain the entire sequence in the admiral s cave sequence between 126 300 900 yr termination ii and historical times a continuous relative age record generated by amino acid epimerization aae geochronology d alloisoleucine l isoleucine or aile ile on the pulmonate land gastropod poecilozonites verifies the biostratigraphy reveals a minimal degree of mixing between stratigraphic units and establishes an independent temporal link between the subterranean and subaerial deposits of bermuda this convergence between stratigraphy and geochronology yields a precisely dated succession from the oceanic island of bermuda and thus presents a unique opportunity to assess the rates and processes of evolutionary and climate change during that interval

precise timing of the last interglacial period from mass spectrometric determination of thorium 230 in corals the development of mass spectrometric techniques for determination of 230 th abundance has made it possible to reduce analytical errors in 238 u 234 u 230 th dating of corals even with very small samples samples of 6 x 10 8 atoms of 230 th can be measured to an accuracy of 3 percent 2 and 3 x 10 10 atoms of 230 th can be measured to an accuracy of 0 2 percent the time range over which useful age data on corals can be obtained now ranges from about 50 to about 500 000 years for young corals this approach may be preferable to 14 c dating the precision with which the age of a coral can now be determined should make it possible to critically test the milankovitch hypothesis concerning pleistocene climate fluctuations analyses of a number of corals that grew during the last interglacial period yield ages of 122 000 to 130 000 years the ages coincide with or slightly postdate the summer solar insolation high at 65 n latitude which occurred 128 000 years ago this supports the idea that changes in pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth s orbit and rotation axis

bermuda sea level during the last interglacial bermuda is a stable mid oceanic carbonate platform for which a particularly complete record of sea level fluctuation during the period 135 70 kyr has been reconstructed from 230th 234u dating of corals and speleothems amino acid racemization dating of molluscs and a reinterpretation of geological field relations during the past 5 yr bermuda has been the focus of an extensive geochronological programme which has included a detailed re examination of the geology to be reported elsewhere1 3 here we focus only on the latest interglacial sequence we use the stratigraphie nomenclature of land et al 4 but will present new age data and interpretations of geological relationships this information as it relates to the last interglacial period is given in tables 1 and 2 and summarized in fig 1 we show that during the last interglacial period sea level was only above its present level for a few thousand years at about 125 kyr when it stood at 4 to 6m at 105 and 85 kyr sea level rose to between 15 and 20 m as constrained by ages for submerged speleothems and eolianites at 95 kyr sea level in bermuda was at least 15 m below present level

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

stemflow influences on the formation of solution pipes in bermuda eolianite abstract soil filled pipes consisting of calcite casings were found in all of the eolianite formations of bermuda except the rocky bay formation the pipes are cylindrical in shape taper vertically downwards and occur in aggregated clusters they are most commonly exposed in areas of shoreline erosion in the form of soil filled cylindrical rims of calcite projecting up from the surrounding host eolianite in the early literature on the geology of bermuda it was suggested that these features were fossilized stumps of the bermuda palmetto tree sabal bermudiana in the study presented here this hypothesis is rejected on the basis of the morphology and stratigraphic position of these geomorphic features and their basal area and areal density compared with existing natural stands of s bermudiana the soil filled pipes of bermuda however cannot be simply explained as random solutional features that correspond to points where percolating soil water happened to converge and cause localized subsurface dissolution in situ measurements of stemflow from indigenous tree species suggest that the soil filled solution pipes of bermuda may be the product of stemflow drainage from particular tree species stemflow from s bermudiana was the most acidic with ph values as low as 4 29 compared to the gross rainfall in the open which had a ph of 5 58 the crowns of the bermuda cedar juniperus bermudiana and the subtropical tree species eugenia axillaris had the most significant funnelling effect stemflow volumes from individual trees representing these two species were 20 times greater than the volume of water that would have been collected in rain gauges with orifice areas equivalent to the trees trunk basal areas tree species capable of acidifying intercepted rainwater and funnelling large quantities down their trunks as stemflow may be the cause of subsurface dissolution loci extending vertically downward through bermuda s soluble eolianite formations stemflow from long lived trees representing these species could account for the diameters the cyclindrical shape the vertical orientation and the soil filled interiors of the pipes successive generations of these trees in preferred habitats could explain their clustered distribution and high areal densities 103 pipes ha

carbonate petrography as an indicator of climate and sea level changes new data from bahamian quaternary units coeval stratigraphic units of similar petrology occur throughout the northern bahamas islands the petrographic composition of these limestones provides clues about regional sea level and climate changes during the late quaternary at least eight fossil shoreline units which are linked to transgressive episodes between the middle pleistocene and the late holocene are recognized in the bahamas the petrographic composition of these units is either dominated by ooids and peloids or by bioclasts sedimentological observations demonstrate that oolitic peloidal units were formed when sea level was higher than today whereas skeletal units were deposited at or below modern ordnance datum skeletal units may reflect times of partial or modest platform flooding when the bulk of sediments brought to islands originates from bank margin reefs in contrast oolitic peloidal units correspond to major flooding events and active water circulation on the bank top cement fabrics further show that the early diagenesis of oolitic units took place during warm and humid climatic conditions whereas skeletal rock bodies underwent subaerial diagenesis during drier climatic conditions characterized by marked seasonal changes this example from the bahamas suggests that compositional analysis of limestone from fossil carbonate platforms could be used for resolving ancient climate and sea level changes

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

sea level and diagenesis a case study on pleistocene beaches whalebone bay bermuda pleistocene fluctuations of sea level have left marine and aeolian limestones intercalated with glacial red soils on the bermuda carbonate platform atlantic 64 50 w 32 20 n successive eustatic highstands of similar amplitude drowned the tectonically stable platform and piled up similar sets of sediments up to three pleistocene beaches are stacked in shorelines sections post depositional diagenetic histories of these beaches can be linked to repeated changes in sea level and pore waters

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

coastal morphology and late quaternary history cayman islands west indies abstract instrumental surveys of coastal profiles in the cayman islands western caribbean reveal the presence of a horizontal erosional bench at 1 9 m on grand cayman and a deep horizontal notch at 6 4 m on cayman brac but no raised erosional features on little cayman each island is surrounded by a horizontal constructional raised reef usually below 2 m here dated by u series methods as 124 000 8000 yr old and hence broadly contemporary with other western atlantic raised reefs of similar elevations the different raised erosional features indicate independent vertical tectonic movement of the three islands predating the formation of the raised reef the accordance and horizontality of the raised reef indicates stability of the islands since the last interglacial times an erosional notch at present sea level has formed since the sea reached its present level less than 2100 b p and algal benches on exposed coasts are also in equilibrium with present conditions

rapid sea level and climate change at the close of the last interglaciation mis 5e evidence from the bahama islands the geology of the last interglaciation sensu stricto marine isotope substage mis 5e in the bahamas records the nature of sea level and climate change after a period of quasi stability for most of the interglaciation during which reefs grew to 2 5 m sea level rose rapidly at the end of the period incising notches in older limestone after brief stillstands at 6 and perhaps 8 5 m sea level fell with apparent speed to the mis 5d lowstand and much cooler climatic conditions it was during this regression from the mis 5e highstand that the north atlantic suffered an oceanographic reorganization about 118 3 ka ago during this same interval massive dune building greatly enlarged the bahama islands giant waves reshaped exposed lowlands into chevron shaped beach ridges ran up on older coastal ridges and also broke off and threw megaboulders onto and over 20 m high cliffs the oolitic rocks recording these features yield concordant whole rock amino acid ratios across the archipelago whether or not the last interglaciation serves as an appropriate analog for our greenhouse world it nonetheless reveals the intricate details of climatic transitions between warm interglaciations and near glacial conditions

low frequency storminess signal at bermuda linked to cooling events in the north atlantic region north atlantic climate archives provide evidence for increased storm activity during the little ice age 150 to 600 calibrated years cal years b p and centered at 1700 and 3000 cal years b p typically in centennial scale sedimentary records meteorological tropical versus extratropical storms and climate forcings of this signal remain poorly understood although variability in the north atlantic oscillation nao or atlantic meridional overturning circulation amoc are frequently hypothesized to be involved here we present records of late holocene storminess and coastal temperature change from a bermudian submarine cave that is hydrographically circulated with the coastal ocean thermal variability in the cave is documented by stable oxygen isotope values of cave benthic foraminifera which document a close linkage between regional temperature change and nao phasing during the late holocene however erosion of terrestrial sediment into the submarine cave provides a storminess signal that correlates with higher latitude storminess archives and broader north atlantic cooling events understanding the driver of this storminess signal will require higher resolution storm records to disentangle the contribution of tropical versus extratropical cyclones and a better understanding of cyclone activity during hemispheric cooling periods most importantly however the signal in bermuda appears more closely correlated with proxy based evidence for subtle amoc reductions than nao phasing

meltwater pulse recorded in last interglacial mollusk shells from bermuda the warm climate of bermuda today is modulated by the nearby presence of the gulf stream current however iceberg scours in the florida strait and the presence of ice rafted debris in bermuda rise sediments indicate that during the last deglaciation icebergs discharged from the laurentide ice sheet traveled as far south as subtropical latitudes we present evidence that an event of similar magnitude affected the subtropics during the last interglacial potentially due to melting of the greenland ice sheet using the clumped isotope paleothermometer we found temperatures 10 c colder and seawater 18o values 2 lower than modern in last interglacial cittarium pica shells from grape bay bermuda in contrast last interglacial shells from rocky bay bermuda record temperatures only slightly colder and seawater 18o values similar to modern likely representing more typical last interglacial conditions in bermuda outside of a meltwater event the significantly colder ocean temperatures observed in grape bay samples illustrate the extreme sensitivity of bermudian climate to broad scale ocean circulation changes they indicate routine meltwater transport in the north atlantic to near equatorial latitudes which would likely have resulted in disruption of the atlantic meridional overturning circulation these data demonstrate that future melting of the greenland ice sheet a potential source of the last interglacial meltwater event could have dramatic climate effects outside of the high latitudes

comparison of amino acid racemization geochronometry with lithostratigraphy biostratigraphy uranium series coral dating and magnetostratigraphy in the atlantic coastal plain of the southeastern united states the results of an integrated study comprising litho and biostratigraphic investigations uranium series coral dating amino acid racemization in molluscs and paleomagnetic measurements are compared to ascertain relative and absolute ages of pleistocene deposits of the atlantic coastal plain in north and south carolina four depositional events are inferred for south carolina and two for north carolina by all methods the data suggest that there are four pleistocene units containing corals that have been dated at about 100 000 yr 200 000 yr 450 000 yr and over 1 000 000 yr some conflicts exist between the different methods regarding the correlation of the younger of these depositional events between charleston and myrtle beach lack of good uranium series dates for the younger material at myrtle beach makes the correlation with the deposits at charleston more difficult

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

the runup of solitary waves this is a study of the runup of solitary waves on plane beaches an approximate theory is presented for non breaking waves and an asymptotic result is derived for the maximum runup of solitary waves a series of laboratory experiments is described to support the theory it is shown that the linear theory predicts the maximum runup satisfactorily and that the nonlinear theory describes the climb of solitary waves equally well different runup regimes are found to exist for the runup of breaking and non breaking waves a breaking criterion is derived for determining whether a solitary wave will break as it climbs up a sloping beach and a different criterion is shown to apply for determining whether a wave will break during rundown these results are used to explain some of the existing empirical runup relationships

the 1960 chilean earthquakes an unusual foreshock sequence that began with an earthquake of moment 2 0 1021 n m and rupture length of about 150 km preceded the great 1960 chilean earthquake earthquake relocations of the sequence show a progression of seismic activity toward the initiation of the main shock the rupture length of the great 1960 chilean earthquake is estimated from the distribution of aftershocks and crustal deformation to be 920 100 km the source mechanisms of a foreshock and two aftershocks are determined and used to constrain the source mechanism of the main shock the first event in the sequence ruptured the segment of the peru chile trench between 37 03 s and 38 74 s whereas the great 1960 chilean main shock ruptured the adjoining segment to the south the great 1960 chilean main shock initiated within the rupture area of the first event and terminated near the intersection of the chile ridge with the peru chile trench 46 5 s

coral indicators of past sea level change a global repository of u series dated benchmarks fossil corals provide valuable data for reconstructing past sea levels as they are often well preserved in the fossil record and can be dated with u series methods here we present a global and internally consistent database of usingle bondth dated fossil coral sea level indicators including full consideration of all known associated uncertainties both vertical and chronological we include carefully determined taxon specific depth distributions rather than blanket depth uncertainty terms as used in most previous work this is based on a synthesis of extensive modern ecological information on depth ranges these ranges are found to be spatially variable between ocean basins between regions and on sub regional scales because depth itself is not limiting instead depth distributions arise from complex physical chemical and biological interactions with coral reef growth distribution and composition one of the main causes for recognition of the greater depth variability of coral taxa has been the routine inclusion of deep diving and rov surveys in coral ecological studies over the past few decades which has broken through the shallow water bias of early surveys by adding frequent observations on deeper occurrences although more are needed it is also clear from our assessment that coral habitat depth distributions must be determined on the species level to reduce uncertainties in reconstructions of past sea levels and that application to sea level studies then requires these studies also to identify fossil corals to the species level samples identified only to the genus level give rise to wide uncertainties in habitat depth and hence sea level our database contains extensive metadata to assist evaluations of dating quality as well as geomorphic and stratigraphic metadata we demonstrate with examples how such metadata can help to evaluate sea level reconstructions for example by identifying outlier points one example discusses the last interglacial lig where we use the available data with their uncertainties to assess probabilistically the time at which local sea levels exceed that of the present which yields a mean age of 124 6 ka with 95 probability bounds at 118 5 and 129 5 ka we conclude with identification of key outstanding issues relating to i current incomplete understanding of tectonic setting including the current lack of independent verification of uplift subsidence rates and reliance of somewhat unsatisfactory and circular use of the elevation of last interglacial deposits ii the depth distributions of coral taxa and iii the complete documentation of stratigraphic geomorphological and other contextual information with suggestions for strategies to address these issues

approximation of surface wave mode conversion at a passive continental margin by a mode matching technique summary at a continental margin sharp structural changes cause strong lateral heterogeneity in s wave velocity p wave velocity and density therefore mode conversion of surface wave modes is expected passive continental margins may be modelled by vertical discontinuities mode conversion is then expressed in terms of re ection and transmission coe cients long period seismograms are calculated by mode summation over incident re ected and transmitted modes re ection and transmission coe cients for surface waves are approximated by a mode matching technique that is adapted to a spherical earth model an orthogonality relation for surface wave eigenfunctions on a spherical earth is given that allows one to simplify the linear system of equations for the determination of re ection and transmission coe cients transmission of fundamental love and rayleigh modes is strongly in uenced by upper crustal heterogeneity for frequencies larger than 40 hz for fundamental love modes and larger than 60 hz for fundamental rayleigh modes mode conversion to neighbouring modes can be strong but mode conversion is not necessarily con ned to neighbouring modes fundamental modes in particular can couple with more distant higher modes in synthetic seismograms calculated for epicentral distances up to 40 0 mode conversion between higher modes and fundamental modes results in shear coupled rayleigh waves

quaternary isotope stratigraphy and paleoclimate of coral reef terraces gulf of aqaba south sinai egypt five quaternary coral reef terraces have been recognized along sharm elsheikh ras mohammed coast of which terraces v to ii form a well developed staircase at um seed while recognized separately at ras mohammed terrace i was only observed as a reef pathches at sharm elsheikh ras mohammed road terraces v to i exist at elevations of 1 b s 1 to 0 m 3 6 m 10 12 m 15 20 m and 25 35 m a s 1 respectively uranium series dates of samples representing terraces v iv iii ii and i show ages grouped as ka 118 125ka 200ka 280 300ka and older 300ka which are related to isotope stages 1 5e 7 9 and 11 respectively the variation of 18o for samples from these terraces show evidence of at least four major warm wet climatic periods in relationship to high sea level and contemporaneous with the formation of the reef terraces faulting affects only the older terraces i and ii and along with the occurrence of terrace iv of last interglacial age at elevation of 3 6 m suggest that the coastal area has not been subjected to major tectonic activities at least with the last 125 ka

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

quaternary stratigraphy and sea level history of the u s middle atlantic coastal plain abstract middle atlantic inner continental shelf stratigraphic studies document a regional late pleistocene fossiliferous mud deposit from northern new jersey to cape lookout north carolina seismic reconnaissance and detailed stratigraphic analyses reveal the nature of the mud termed unit q2 on the maryland inner continental shelf extensive amino acid relative age determinations from the single genus mulinia combined with additional amino acid analyses from onshore deposits having radiometric dates for calibration indicate an age range for unit q2 corresponding to oxygen isotope stage 5 ostracode assemblages delineate four distinct climatic episodes in unit q2 enabling correlation of the zones in q2 to the deep sea isotopic record of climatic fluctuations substages in stage 5 late stage 5 is represented on the maryland shelf by the 6 meter thick mud of unit q2 deposited in an open shelf environment at slightly depressed sea levels relative to substage 5e late stage 5 sea levels including sea level minima can be estimated for the mid atlantic coastal plain by direct measurement of the altitudes of ostracode zone boundaries offshore and from peak transgressive facies in correlative deposits onshore late stage 5 sea levels determined from the inner shelf and adjacent nearshore facies on the atlantic coast comprise the most complete sea level history for stage 5 yet proposed some recent revisions of glacioeustatic sea level models advocate slightly higher sea levels during late stage 5 substage 5c in particular than originally estimated from uplifting reef tracts and support sea levels higher than estimates from deep sea isotopic records the sea level record from the maryland inner continental shelf confirms these recent estimates in an area of minimal tectonism and adds sea level minima estimates for substages 5d and 5b offshore a more complete record of stage 5 is preserved than in onshore deposits which are limited to peak transgressive facies discrepancies in correlation among emerged coastal plain facies therefore become resolvable within the context provided by the shelf stratigraphy

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

a study of the 2015 mw 8 3 illapel earthquake and tsunami numerical and analytical approaches the september 16 2015 illapel chile earthquake triggered a large tsunami causing both economic losses and fatalities to study the coastal effects of this earthquake and to understand how such hazards might be accurately modeled in the future different finite fault models of the illapel rupture are used to define the initial condition for tsunami simulation the numerical code non hydrostatic evolution of ocean waves neowave is employed to model the tsunami evolution through the pacific ocean because only a short time is available for emergency response and since the earthquake and tsunami sources are close to the coast gaining a rapid understanding of the near field run up behavior is highly relevant to chile therefore an analytical solution of the 2 1 d shallow water wave equations is considered with this solution we show that we can quickly estimate the run up distribution along the coastline to first order after the earthquake and tsunami field observations were measured in the surrounded coastal region where the tsunami resulted in significant run up first we compare the analytical and numerical solutions to test the accuracy of the analytical approach and the field observations implying the analytic approach can accurately model tsunami run up after an earthquake without sacrificing the time necessary for a full numerical inversion then we compare both with field run up measurements we observe the consistency between the two approaches to complete the analysis a tsunami source inversion is performed using run up field measurements only these inversion results are compared with seismic models and are shown to capture the broad scale details of those models without the necessity of the detailed data sets they invert

rapid sea level changes at the close of the last interglacial substage 5e recorded in bahamian island geology rapid and abrupt relative sea level changes within the last interglacial substage 5e are recorded in the island geology of the tectonically stable bahamas from 132 to 118 ka reef growth reached a maximum elevation near 2 m as indicated by fossil reef elevation across the platform whereas bioeroded notches are incised in coastal cliffs as high as 6 m the end of the interval is characterized by voluminous eolianites exhibiting palm tree and frond impressions it is inferred that sea level for most of the interval remained near 2 m restraining reef growth and that the notch at 6 m represents a rapid and brief excursion just before the close of the substage the subsequent fall must have been rapid in order to leave the notch profile intact and mobilize windward lagoon ooids into dunes before cementation could anchor them in order to explain the rapid rise to 6 m glacial surging is invoked the subsequent fall also rapid may be a consequence of the surge flooding high latitudes and providing enough moisture to initiate reglaciation and drawdown

geochronology biostratigraphy and changing shell morphology in the land snail subgenus poecilozonites during the quaternary of bermuda shells from over 280 collections representing all known forms of subgenus poecilozonites zonitidae from bermuda have been ranked in stratigraphic order and relative age aminostratigraphy the samples were first grouped by their source lithostratigraphic unit with additional refinements being made based on the epimerization ratio d alloisoleucine l isoleucine or a i from nearly 400 representative individual shells of each of the forms a plot of a i frequency defines several modes or aminozones the aminozones correlate strongly with defined lithostratigraphy with some minor variation resulting from less optimally preserved shells the succession of land snails is ranked over chronological range from the middle and early pleistocene with greatest resolution since 500 ka this 500 ka age range and density of sampling is among the most extensive for any organism on an oceanic island morphological analysis of poecilozonites demonstrates oscillation and repetition of morphotypes over multiple sea level cycles shells from the small island s that formed during interglacial times are generally small and show little variation in form during glacial periods when bermuda reached maximal size shells are much larger extreme variation in shell size and shape occurs at interglacial glacial transitions in as little as 2 4 ka because the subgenus has been endemic to bermuda for at least ca 1000 ka such dramatic and rapid shifts in shell morphology cannot be the result of recolonization from outside sources an intact and undisturbed 130 ka long biostratigraphic record of poecilozonites is contained in a single vertical 2 m thick talus accumulation in admirals cave that has been dated at high resolution by three independent techniques the bio and chronostratigraphy show that snails were very large at the close of glacial stage marine isotope stage mis 6 small during interglacial mis 5 re evolved identical large size during the last glaciation mis 4 2 and changed abruptly to the small paedomorphic modern form at the onset of the holocene mis 2 1 about 10 12 ka ago when assessed with care shells of poecilozonites may be used as guide fossils for rapid field identification of lithostratigraphic units in surface deposits and as chronological indicators in cave and fissure fills when used in combination with vertebrate remains

last interglacial stratigraphy in the burg el arab region of the northwestern coast of egypt abstract the northwestern coast of egypt a stable carbonate platform is characterized by the presence of successive coastal ridges that extend parallel to the present shoreline study of marine deposits at the bottom of gebel maryut ridge from the drain cut of bahig together with analyses of core samples raised from four boreholes drilled in the el dekheilla depression to the depths of 10 15 m reveal the presence of two phases of beach boulders the lower older phase b b 1 wedge eolianites e 1 at an elevation of 3 4 m and show an average 18o of 0 82 the upper younger phase b b ii wedge eolianites e 2 at 6 7 m a s l with an average 18o of 1 5 these beach boulders are overlained by thick fossiliferous limestones and geosoils they record the last interglacial high sea level isotope substage 5e and aminozone e with an interpolated age of 125 ka which was globally 6 8 m higher than present sea level with characteristic warm wet tropical climatic conditions a bed composed of marine molluscs and foraminifera shells with ooids and pellets below the loamy calcareous and evaporites of the el dekheilla depression was also examined this bed is located 1 4 m b s l with an average 18o of 0 25 it is related to aminozone c isotope substage 5c 5a with an interpolated age of 110 ka and related to a transgressive sea with a mean sea level possibly equal to or slightly lower than the present one with evidence for less warm climatic conditions

sea level controls sedimentation and environments in coastal caves and sinkholes abstract quaternary climate and sea level research in coastal karst basins caves cenotes sinkholes blueholes etc generally focuses on analyzing isotopes in speleothems or associating cave elevations prior sea level highstands the sediments in coastal karst basins represent an overlooked source of climate and sea level information in the coastal zone but to accurately interpret these sediments first requires an understanding of the forcing mechanisms that emplace them in this study we hypothesize that coastal karst basins transition through vadose littoral anchialine and finally into submarine environments during sea level rise because groundwater and sea level oscillate in near synchrony in the coastal zone causing each environment to deposit a unique sedimentary facies to test this hypothesis the stratigraphy in twelve sediment cores from a bermudian underwater cave green bay cave was investigated and temporally constrained with twenty radiocarbon dates the results indicate that we recovered the first succession spanning the entire holocene from an underwater cave 13 ka to present the sediments were characterized with x radiography fossil remains bulk organic matter organic geochemistry 13corg c n and grain size analysis four distinct facies represent the four depositional environments i vadose facies 7 7 ka calcite rafts lithofacies ii littoral facies 7 7 to 7 3 ka calcite rafts and mud lithofacies iii anchialine facies 7 3 to 1 6 ka slackwater and diamict lithofacies and iv submarine facies

morphometric analysis and amino acid geochronology of uplifted shorelines in a tectonic region near reggio calambria south italy the tectonic coastline of the calabrian peninsula provides an opportunity to study the morphology and history of elevated marine shorelines near capo dell armi eleven shorelines are preserved between sea level and 256 m with some correlation difficulties posed by the dissection of the area by intermittent streams we are able to correlate several of the shorelines across the entire study area with the support of correlations provided by amino acid geochronology we have identified four shorelines dating from the last interglacial period isotope stage 5 the oldest two both contain the strombus bubonius fauna and are of indistinguishable early last interglacial ages stage 5e aminozone e ca 125 ka the highest terrace vii is associated with a shoreline at 157 m and the lower with a shoreline around 125 105 m a s l of the two younger stage 5 without strombus bubonius the higher v lies at about 90 100 m and produces amino acid ratios slightly younger than but statistically indistinguishable from those of aminozone e however the youngest last interglacial shoreline deposits iv have produced amino acid ratios correlated to late stage 5 5a elsewhere in the mediterranean basin amino acid and geomorphic data have shown that uplift varies the study area from 0 85 to 1 03 m ka and suggeststhat constant uplift along any one traverse is unlikely

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