development and demise of a fringing coral reef during holocene environmental change eastern ningaloo reef western australia abstract reefs lining the western exmouth gulf located at the northern limit of the 300 km long ningaloo reef in western australia represent modern incipient coral reefs and veneers of non reef building coral algal communities on exposed pleistocene or give up holocene reef surfaces acquisition of sixteen cores alongside u series tims dates were used to confirm the nature of the pleistocene foundation and characterise holocene reef development three calcretised pleistocene units were identified as 1 the last interglacial mis 5e reef directly underlying holocene units 2 a mid pleistocene mis 7 bioclastic conglomerate unit and 3 a pleistocene alluvial fanglomerate eight holocene reef facies total thickness of 1 8 5 3 m included coral framework facies domal arborescent mixed tabulate and encrusting and detrital facies carbonate sand skeletal rubble and alluvial fan deposits holocene ages range from 7 93 to 5 8 ka bp with vertical accretion ranging from 1 46 to 9 88 mm year avg 4 11 mm year highest rates of accretion and thickest accumulation occurred in the most seaward and deepest cores composed of massive coral framestone and coralline algal crusts a six stage holocene chronology is proposed including 1 coastal inundation from 8 to 8 5 ka bp 2 initiation start up from 8 to 7 5 ka bp 3 rapid growth catch up and back step from 7 5 to 7 ka bp 4 rapid aggradational growth catch up from 7 to 6 5 ka bp 5 reef decline give up and detrital buildup from 6 5 to 5 8 ka bp and 6 detrital buildup and progradation from 5 8 ka bp to present changes in reef facies and the ultimate demise of the holocene reef probably involved a combination of increased sea level coastal flooding and erosion during the mid holocene highstand with associated increase in sedimentation turbidity and decline in water quality burial by sediment buildup during the mid holocene highstand and detrital progradation during the mid to late holocene regression and the introduction of alluvial sediment during cyclones and other severe storms to an already stressed community modern communities have thus shifted from coral dominated to bored macroalgal pavements this study shows that integration of reef development processes with response to environmental change can be used to assess future pressures on coral reef ecosystems globally

facies outcrop gamma ray and c o isotopic signature of exposed miocene subtropical continental shelf carbonates north west cape western australia abstract exposed uplifted miocene carbonate sequences of the cape range north west cape western australia provide outcrop analogues of seismic sequences from offshore parts of the shelf facies include deep shelf marls very fine and fine packstone larger foram wackestone floatstone and muddy rudstone foram coralline algal skeletal fragment packstone wackestone shallow seagrass facies lagoonal wackestone mudstone with scattered corals and tidal flat laminites the exposed early miocene units include the mandu highstand a sequence in the tulki and one in the middle miocene trealla limestone sequences contain decameter scale 5 20 m thick 4th order parasequences evident on gamma ray logs and by facies stacking that shallow and coarsen up they appear to be due to eccentricity driven sea level changes which may have been up to 50 m higher frequency meter scale parasequences of deep water marl up into larger foram rudstone floatstone perhaps precession obliquity are evident at the base of the exposed mandu section these parasequences are not merely random storm deposits this is indicated by the covariance of c and o isotopes with the lighter values associated with deepening and deposition of deep shelf marls and the heavier values being associated with shallowing and deposition of larger foram facies the uplifted miocene continental shelf sediments of the north west cape preserve a record of eustasy paleoclimate and paleoceanography and thus provide a window into factors affecting the shelf that can be compared with coeval better studied deep sea cores

how many oceans meliata vardar and pindos oceans in mesozoic alpine paleogeography the timing of rifting and subduction in the meliata vardar and pindos zones of the hellenic dinaric carpathian region indicates that they cannot be considered remnants of a single ocean basin in contrast to several recently published mesozoic paleogeographies sea floor spreading in the meliata zone culminated in middle triassic ladinian time and ceased in the late triassic and subduction occurred from this time until late jurassic closure in contrast sea floor spreading in the vardar zone began in early jurassic time and culminated in the middle jurassic and subduction occurred from latest jurassic time in the pindos zone sea floor spreading was initiated in the early triassic with late jurassic and early tertiary subduction

evidence for ocean acidification in the great barrier reef of australia geochemical records preserved in the long lived carbonate skeleton of corals provide one of the few means to reconstruct changes in seawater ph since the commencement of the industrial era this information is important in not only determining the response of the surface oceans to ocean acidification from enhanced uptake of co2 but also to better understand the effects of ocean acidification on carbonate secreting organisms such as corals whose ability to calcify is highly ph dependent here we report an 200 year d 11 b isotopic record extracted from a long lived porites coral from the central great barrier reef of australia this record covering the period from 1800 to 2004 was sampled at yearly increments from 1940 to the present and 5 year increments prior to 1940 the d 11 b isotopic compositions reflect variations in seawater ph and the d 13 c changes in the carbon composition of surface water due to fossil fuel burning over this period in addition complementary ba ca d 18 o and mg ca data was obtained providing proxies for terrestrial runoff salinity and temperature changes over the past 200 years in this region positive thermal ionization mass spectrometry ptims method was utilized in order to enable the highest precision and most accurate measurements of d 11 b values the internal precision and reproducibility for d 11 b of our measurements are better than 0 2 2r which translates to a precision of better than 0 02 ph units our results indicate that the long term pre industrial variation of seawater ph in this region is partially related to the decadal interdecadal variability of atmospheric and oceanic anomalies in the pacific in the periods around 1940 and 1998 there are also rapid oscillations in d 11 b compositions equivalent changes in ph of almost 0 5 u the 1998 oscillation is co incident with a major coral bleaching event indicating the sensitivity of skeletal d 11 b compositions to loss of zooxanthellate symbionts importantly from the 1940s to the present day there is a general overall trend of ocean acidification with ph decreasing by about 0 2 0 3 u the range being dependent on the value assumed for the fractionation factor a b3 b4 of the boric acid and borate species in seawater correlations of d 11 b with d 13 c during this interval indicate that the increasing trend towards ocean acidification over the past 60 years in this region is the result of enhanced dissolution of co2 in surface waters from the rapidly increasing levels of atmospheric co2 mainly from fossil fuel burning this suggests that the increased levels of anthropogenic co2 in atmosphere has already caused a significant trend towards acidification in the oceans during the past decades observations of surprisingly large decreases in ph across important carbonate producing regions such as the great barrier reef of australia raise serious concerns about the impact of greenhouse gas emissions on coral calcification 2009 elsevier ltd all rights reserved

three dimensional modeling of tsunami forces on coastal communities abstract recent research on tsunami inundation of coastal communities has largely focused on numerical modeling of tsunami runup on two dimensional 2d slopes or three dimensional 3d topographies with more complex shorelines the coastal bathymetry that are generally applied are based on bare earth topography few studies have simulated overland flow around existing macro roughness features such as nearshore buildings and bridges this is often due to both lack of available data and the fact that it can be computationally demanding to incorporate these additional features a consequence of omitting the built infrastructure from models is that to predict tsunami forces and corresponding structural demand extrapolations from overland flow data is necessary and for densely populated communities these flow predictions may not be appropriate in this work a high resolution 3d computational fluid dynamics approach is used to model tsunami inundation of a 1 50 model scale idealized community representative of the town of seaside or usa for which existing experimental data is available several buildings were selected and flow characteristics water level velocity and momentum flux in the vicinity of these buildings were validated against experimental data several computational domains were analyzed and it is shown that local flow characteristics can be captured using subdomains of the community reducing computational demand force predictions using direct integration of predicted pressure were compared with bare earth momentum flux calculations and the importance of incorporating the constructed environment in force prediction models is discussed finally comparisons with seismic load predictions for a selected building are presented for comparison

holocene and pleistocene fringing reef growth and the role of accommodation space and exposure to waves and currents bora bora society islands french polynesia holocene fringing reef development around bora bora is controlled by variations in accommodation space as a function of sea level and antecedent topography and exposure to waves and currents subsidence ranged from 0 to 0 11 m kyr 1 and did not create significant accommodation space a windward fringing reef started to grow 8 7 kyr bp retrograded towards the coast over a pleistocene fringing reef until ca 6 0 kyr bp and then prograded towards the lagoon after sea level had reached its present level the retrograding portion of the reef is dominated by corals calcareous algae and microbialite frameworks the prograding portion is largely detrital the reef is up to 13 5 m thick and accreted vertically with an average rate of 3 12 m kyr 1 lateral growth amounts to 13 3 m kyr 1 reef corals are dominated by an inner pocillopora assemblage and an outer acropora assemblage both assemblages comprise thick crusts of coralline algae palaeobathymetry suggests deposition in 0 to 10 m depth an underlying pleistocene fringing reef formed during the sea level highstand of marine isotope stage 5e and is also characterized by the occurrence of corals coralline algal crusts and microbialites a previously investigated leeward fringing reef started to form contemporaneously 8 78 kyr bp but is thicker up to 20 m and solely prograded throughout the holocene a shallow pocillopora assemblage and a deeper water montipora assemblage were identified but detrital facies dominate at the holocene reef base only basalt was recovered the holocene windward leeward differences are a consequence of less accommodation space on the eastern island side that eventually led to a more complex reef architecture as a result of higher rates of exposure and flushing the reef framework on the windward island side is more abundant and experienced stronger cementation in the pleistocene the environmental conditions on the leeward island side were presumably unfavourable for fringing reef growth

tsunami inundation modeling in constructed environments a physical and numerical comparison of free surface elevation velocity and momentum flux abstract a laboratory benchmark test for tsunami inundation through an urban waterfront including free surface elevation velocity and specific momentum flux is presented and compared with a numerical model coulwave the physical model was a 1 50 scale idealization of the town seaside oregon designed to observe the complex tsunami flow around the macro roughness such as buildings idealized as impermeable rectangular blocks free surface elevation and velocity time series were measured and analyzed at 31 points along 4 transects optical measurements of the leading bore front were used in conjunction with the in situ velocity and free surface measurements to estimate the time dependent specific momentum flux at each location the maximum free surface elevation and specific momentum flux sharply decreased from the shoreline to the landward measurement locations while the cross shore velocity slowly decreased linearly the experimental results show that the maximum specific momentum flux is overestimated by 60 to 260 if it is calculated using the each maximum values of the free surface elevation and cross shore velocity comparisons show that the numerical model is in good agreement with the physical model at most locations when tuned to a friction factor of 0 005 when the friction factor decreased by a factor of 10 from 0 01 to 0 001 the average maximum free surface elevation increased 15 and the average cross shore velocity and specific momentum flux increased 95 and 208 respectively this highlights the importance of comparing velocity in the validation and verification process of numerical models of tsunami inundation

sedimentary evolution of the holocene subaqueous clinoform off the shandong peninsula in the yellow sea abstract a subaqueous clinoform wraps around the end of the shandong peninsula in the yellow sea the clinoform previously called the shandong mud wedge is up to 40 m thick nearshore and thins seaward its origin has been controversial since it was first noted in the 1980s for our recent investigation offshore of the northeastern shandong peninsula high resolution shallow seismic profiles covering about 1700 km were obtained and two drilling cores penetrating the clinoform were recovered we described the lithofacies characteristics identified benthic foraminifera and ostracoda measured grain size analyzed the mineral components of the cores and obtained ams 14 c dates on 28 samples to decipher the sedimentary evolution of the clinoform in response to postglacial sea level changes the shallow seismic profiles show that the clinoform comprises three units a lowermost seismic unit su 3 less than 2 3 m thick showing a retrogradational aggradational stacking pattern with subhorizontal internal reflectors a middle seismic unit su 2 up to 35 m thick showing a prograding reflection pattern with mostly seaward stepping reflectors separated by several erosive surfaces and an uppermost seismic unit su 1 maximum thickness 18 m exhibiting an aggradational reflection pattern with subparallel reflectors the three seismic units are bounded on the bottom by distinct erosion surfaces analyses of the two cores indicate that the clinoform comprises three depositional units du 1 du 2 and du 3 in descending order corresponding respectively to su 1 su 2 and su 3 the depositional units are distinguished by lithofacies characteristics and the downcore distributions of benthic foraminiferal and ostracod assemblages mineral components of the cores suggest that the clinoform s provenance is predominantly yellow river derived sediments ams 14 c dates suggest that du 3 was formed from about 11 6 to 9 6 cal kyr bp du 2 from 9 6 to 6 5 cal kyr bp and du 1 after ca 6 5 cal kyr bp some major meltwater pulse mwp events during the deglacial transgression were registered in the clinoform stratigraphy with the basal surfaces sediments of du 3 and du 2 corresponding respectively to mwp 1b ca 11 6 11 3 cal kyr bp and mwp 1c ca 9 6 9 2 cal kyr bp events and with du 2 being largely formed after the 8 4 8 2 cal kyr meltwater event rapid centennial to multidecadal scale flooding events were presumably responsible for the erosive surfaces separating the downlapping internal reflectors in su 2 the change of depositional pattern from progradational in su 2 to aggradational in su 1 is attributed to a change from strong dominantly to and fro tidal currents to the modern circulation in the bohai sea as well as to the weakening of the tidal current field during the highstand after about 6500 cal yr bp as a product of complex interactions among sediment supply sea level changes and hydrodynamic regimes the clinoform can be regarded as the distal part of the tidal depositional system in the eastern bohai sea which was largely derived from the yellow river

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

modern coral reefs of western atlantic new geological perspective contrary to popular belief of the late 1960s western atlantic holocene reefs have a long history and are not feeble novice nearshore veneers that barely survived postglacial temperatures rather the growth of these reefs kept pace with the rising seas of the holocene transgression and their development was for the most part controlled by offshore wave energy conditions and the relationship between changing sea levels and local shelf topography thus the outer shelves of the eastern caribbean in areas of high energy have relict reefs consisting predominantly of acropora palmata a robust shallow water coral the flooding of adjacent shelves during the postglacial transgression introduced stress conditions that terminated the growth of these reefs when about 7 000 r ago shelf water conditions improved scattered deeper water coral communities reestablished themselves on these stranded shelf edge reefs and fringing and bank barrier reefs began to flourish in shallow coastal areas at the same time the fragile and rapidly growing acropora cervicornis and other corals flourished at greater depths on the more protected shelves of the western caribbean and the gulf of mexico as a result late holocene buildups more than 30 m thick developed in those areas

mechanisms of spur and groove development and implications for reef platform evolution contemporary understanding of holocene coral reef development is based primarily on sub surface investigations of reef flat back reef and lagoon zones few studies of holocene fore reef development exist constituting a significant gap in our understanding of reef evolution the spur and groove sag zone is a distinct understudied feature of fore reefs worldwide we review sag development from previous studies and present 29 new sag short cores with 52 14c and u th ages from six fore reef regions of heron and one tree reefs the first such data from the great barrier reef remarkably we found that sags do not necessarily accrete in the same direction as their adjacent reef flat we identified three modes of reef flat and sag lateral accretion mode 1 lagoonward accretion of both the reef flat and sags mode 2 lagoonward accretion of the reef flat but seaward accretion of the sags mode 3 seaward accretion of both the reef flat and sags most sag zones five of the six studied accreted in a seaward direction modes 2 or 3 hydrodynamic conditions and local topography appear to be the dominant factors determining which mode occurs episodic high energy events are also likely to play an important role in sag formation our findings suggest that traditionally held models of reef evolution whereby lagoonal mature reefs fill developing into senile platform reefs may not hold rather reef flats may continue to expand seaward on their leeward and semi exposed fronts to increase in size while maintaining their lagoons

back to the future the history of acroporid corals at the flower garden banks gulf of mexico usa fossil elkhorn corals acropora palmata were discovered at the flower garden banks fgb on the shelf margin off the texas coast in 2006 radiocarbon dating revealed an a palmata dominated community aged 10 157 6838 cal bp the acropora reefs correspond in time to an interval of warmer than present sea surface temperatures ssts during the holocene thermal maximum htm the subsequent demise of a palmata in the middle holocene was a consequence of the inability of the shallowest reef facies to keep pace with rising sea level following complete submergence of the banks possibly coupled with decreasing ssts following the htm in 2007 the first fossil staghorn corals acropora cervicornis were discovered at the fgb based on radiocar bon dating of these corals to 1027 211 cal bp it appears that populations of a cervicornis flourished in deeper waters 25 32 m depth on the edges of the banks until the peak of the little ice age lia when they died pre sumably from cold water exposure the recent return of a palmata to reefs of the fgb associated with increasing sea temperatures appears to be both an echo of the past and a harbinger of the future 2013 published by elsevier b v

global change and modern coral reefs new opportunities to understand shallow water carbonate depositional processes human activities are impacting coral reefs physically biologically and chemically nutrification sedimentation chemical pollution and overfishing are significant local threats that are occurring worldwide ozone depletion and global warming are triggering mass coral bleaching events corals under temperature stress lose the ability to synthesize protective sunscreens and become more sensitive to sunlight photo oxidative stress also reduces fitness rendering reef building organisms more susceptible to emerging diseases increasing concentration of atmospheric co2 has already reduced caco3 saturation in surface waters by more than 10 doubling of atmospheric co2 concentration over pre industrial concentration in the 21st century may reduce carbonate production in tropical shallow marine environments by as much as 80 as shallow water reefs decline worldwide opportunities abound for researchers to expand understanding of carbonate depositional systems coordinated studies of carbonate geochemistry with photozoan physiology and calcification particularly in cool subtropical transition zones between photozoan reef and heterotrophic carbonate ramp communities will contribute to understanding of carbonate sedimentation under environmental change both in the future and in the geologic record cyanobacteria are becoming increasingly prominent on declining reefs as these microbes can tolerate strong solar radiation higher temperatures and abundant nutrients the responses of reef dwelling cyanobacteria to environmental parameters associated with global change are prime topics for further research with both ecological and geological implications

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

a new model of holocene reef initiation and growth in response to sea level rise on the southern great barrier reef the fossil record provides valuable data for improving our understanding of both past and future reef resilience and vulnerability to environmental change the spatial and temporal pattern of the initiation of the holocene great barrier reef presents a case study of reef response to rapid sea level rise past studies have been limited by the lack of well dated and closely spaced reef core transects and have not closely examined the composition of the reef building communities through time this study presents 80 new high precision u sbnd th and 5 radiocarbon ages from twelve new cores located along three transects across different geomorphic and hydrodynamic settings of one tree reef southern great barrier reef to document three distinct stages of holocene reef development in unprecedented detail temporal constraints on changing paleoecological assemblages of coral coralline algae and associated biota revealed three distinct phases of reef development consisting of 1 a fast shallow and clear water reef initiation from 8 2 until 8 ka 2 a shift to slower deeper and more turbid water reef growth from 8 to 7 ka and 3 a return to shallow and rapid branching coral growth in clear water conditions as the reef catches up to sea level a minimum lag prior to reef initiation of 700 years was identified which differs in length depending on reef environment and pleistocene substrate height in this new model reef growth initiated on the topographically lower leeward margin and patch reef prior to the start of windward margin development contrary to the traditional reef growth model while there was a shift to conditions less favorable for reef growth at 8 ka this did not prevent the slow accretion of more sediment tolerant coral communities the majority of the reef reached sea level by 6 ka this new conceptual model of holocene reef growth provides new constraints on changes in paleoenvironment that controlled reef community composition and growth trajectories through sea level rise following inundation

holocene development of the yellow river s subaqueous delta north yellow sea high resolution seismic profiles from the north yellow sea reveal a 20 40 m thick subaqueous clinoform delta that wraps around the eastern end of the shandong peninsula extending into the south yellow sea this complex sigmoidal oblique clinoform containing an estimated 400 km 3 of sediment overlies prominent relict transgressive surfaces the nearshore topset of the clinoform 50 m contain less than 1 m of holocene sediment with low sedimentation rates 1 mm year in contrast to other clinoforms the shandong clinoform appears to be a compound subaqueous deltaic system with what we interpret to be proximal and distal phases of clinoform development the underlying proximal sequence formed proximally between f11 and 9 2 ka in response to a temporary pause in the rapid postglacial sea level rise after the meltwater pulse 1b mwp 1b and increased discharge from the yellow river to the north yellow sea due to intensification of the summer monsoon a flooding surface appears to separate the proximal and distal phases corresponding to the next rapid sea level rise 9 5 9 2 ka bp mwp 1c since 9 2 ka bp an overlying distal sedimentary sequence has accumulated reflecting the backstepping and shifting river mouth westward to the gulf of bohai some inputs from coastal erosion and nearby small streams may be locally important along shore transport cross shelf advection and upwelling in the north yellow sea have reworked post lgm sediment and have helped maintain the morphology of the clinoform in the shandong mud wedge d 2004 elsevier b v all rights reserved

the future of coral reefs in an age of global change coral reefs are the only ecosystem that is strongly defined by a geological component most definitions require that the biological community produces its own build up of calcium carbonate in terms of reef building the geological record reveals that coral reefs have flourished over the past few million years particularly during interglacial periods based on our observations of modern day reefs which are limited to the past few centuries we tend to link coral reef health to carbonate production however reef ecosystems face future global scale environmental changes that may decrease their reef building capacity in contrast to past discussions of the factors which determine reef building potential by a coral reef community the essential question that arises from this review is how important is reef building to a coral reef community

new evidence for drowned shelf edge reefs in the great barrier reef australia we present four new high resolution multibeam bathymetry datasets from the shelf edge of the northern great barrier reef gbr analysis of these data combined with chirp sub bottom profiles and existing submersible observation data provides a fresh insight into the detailed morphology and spatial distribution of submerged reefs and terraces at the shelf edge an extensive and persistent line of drowned shelf edge reefs exist on the gbr margin in about 40 to 70 m they appear as barrier reefs up to 200 m wide and comprising twin parallel ridges of rounded pinnacles subtle yet consistent terrace and step features lie between 78 and 114 m seaward of the shelf edge reefs in the southern study area submersible observations confirm that the drowned reefs now provide a favorable hard substrate for live soft corals and algae they form a consistent and extensive seabed habitat that extends for possibly 900 km along the gbr shelf edge the submerged reef and terraces features may reflect a complex history of growth and erosion during lower sea levels and are now capped by last deglaciation reef material

stratigraphic architecture and evolution of a barrier seagrass bank in the mid late holocene shark bay australia abstract within the faure sill complex shark bay western australia a combination of remote sensing analysis seismic stratigraphy and cores to ground truth together with radiocarbon dating demonstrate the interconnection between sediment body morphologies seagrass related substrates and pre existing topography and reveal the system as a channel bank complex sea level fluctuations appear to have largely controlled the hydrodynamic conditions of the bank contributing to each stage of its evolution 1 not earlier than 8 5 8 0 ka bp in a lowstand period after an erosive event of underlying palaeosurfaces seagrass establishment progressively contributed to initiating bank growth 2 around 6800 years bp bank accumulation reached its apex in conjunction with a rapid sea transgression 3 during the late holocene succeeding a slow decline to present sea level bank growth continued to fill available accommodation space and a number of hiatuses indicating temporal and spatial discontinuities within the process of bank building are recognised average depositional rates of bank building 1 3 m ka conform to previous estimates derived for seagrass banks but rates are strongly facies dependent attesting to the dynamic nature of this channel bank complex the extensive seagrass meadows are essential for a wide range of aspects of the environment of the shark bay area not only are they particularly important for the entire shallow benthic ecosystem but they also had a major role in the partial closure of the southern basins and hence determining the development of hypersaline conditions and associated oolitic microbial and evaporitic facies in hamelin pool and l haridon bight moreover this system has a critical role in producing sequestering and storing organic carbon

late glacial to post glacial sea levels in the western indian ocean late glacial to post glacial sea level changes provide direct evidence of the progress of melting of large ice sheets during the last deglaciation but although the correlation between ice and ocean volumes is incontrovertible the causal link is commonly obscured local effects including tectonics isostatic and hydroisostatic responses and equatorial ocean syphoning impose additional signals that hide the true picture a detailed regional study of the western indian ocean based on the analysis of drill cores carried out through modern reefs in combination with observations and sampling of reef foreslopes and investigations of outcrops provides a comprehensive data base sites from a range of tectonic settings include the microcontinental margins of madagascar the granitic seychelles and the isolated volcanic islands of reunion mauritius and the comoros in which the effects of subsidence can be shown to be small these cover a range of latitudes and comparisons with adjacent sites on continental margins allow the construction of sea level curves that closely reflect the eustatic response and disengage this from the effects of other mechanisms the mayotte foreslope in the comoro islands provides the first coral reef record of sea level change during the early deglaciation in the indian ocean 110 115 m below present sea level between 18 000 and 17 000 yr bp two distinctive reef terraces at 90 and 60 m water depth are dated at 13 600 yr bp and partly attributed to the younger dryas period 12 700 11 600 cal yr bp reef drowning at around 13 500 yr bp may correspond to meltwater pulse 1a and although there were surges in the rate of sea level rise most notably between 11 950 and 11 350 yr bp there is little evidence to support a well defined meltwater pulse 1b reconstructed holocene sea level curves are in good agreement and reflect a rapid sea level rise of about 6 mm yr 1 between 10 000 and 7500 yr bp followed by a clear inflection around 7500 yr bp when the rate fell to 1 1 mm yr 1 modern reefs started to grow 8000 9000 years ago in the post glacial period the rate of sea level rise was 1 1 5 mm yr 1 before stabilization at its present level 3000 2500 years ago curves for the 10 000 6000 yr 1 bp interval correspond closely with those predicted by theoretical models but lie below these in the subsequent period in particular and with the exception of the margins of the madagascar microcontinent influenced by hydroisostatic processes they do not reflect predicted higher sea level stands during the late holocene

geomorphic evidence of major sea level fluctuations during marine isotope substage 5e cape cuvier western australia abstract a detailed geomorphologic and morphostratigraphic investigation of raised marine terraces at cape cuvier western australia reveals two morphologically distinct units a lower well developed accretional reef terrace between 3 and 5 5 m above mlws mean low water springs hereafter denoted as represents an extended interval of stable sea level an upper erosional terrace and incipient coralgal rim between 8 5 to 10 5 m represents a brief sea level stillstand at this higher elevation these features suggest the lower and upper terraces developed during discrete sea level events in an attempt to better define the timing of emplacement of each marine unit 20 coral samples collected along vertical and lateral reef growth axis from both terraces were analysed with u series dating unfortunately all coral samples exhibited elevated 234 u initial values suggesting that pervasive uptake of 234 u enriched uranium and 230 th thorium had occurred despite the shortcomings of absolute dating a succession of events can be resolved though morphostratigraphic relationships comparison of the facies relationships coral growth and morphostratigraphic features between the lower and upper terraces indicates that an early to mid mis 5e stillstand at 3 to 5 m was followed by a late rise to 8 5 to 10 5 m this agrees with an emerging global view of mis 5e sea level history derived from stable carbonate platforms rejecting the hypothesis that these higher sea level benchmarks are an artefact of localized tectonic processes

holocene climatic instability a prominent widespread event 8200 yr ago the most prominent holocene climatic event in greenland ice core proxies with approximately half the amplitude of the younger dryas occurred 8000 to 8400 yr ago this holocene event affected regions well beyond the north atlantic basin as shown by synchronous increases in windblown chemical indicators together with a significant decrease in methane widespread proxy records from the tropics to the north polar regions show a short lived cool dry or windy event of similar age the spatial pattern of terrestrial and marine changes is similar to that of the younger dryas event suggesting a role for north atlantic thermohaline circulation possible forcings identified thus far for this holocene event are small consistent with recent model results indicating high sensitivity and strong linkages in the climatic system

a new coral reef province in the gulf of carpentaria australia colonisation growth and submergence during the early holocene abstract multibeam sonar mapping drill cores and underwater video data have confirmed the existence of a previously unknown coral reef province in the gulf of carpentaria australia seven reefs comprised of coral limestone that support living corals have been mapped so far and as many as 50 other reefs may exist in the region u th ages show that reef growth commenced shortly after limestone pedestals were submerged by rising sea level around 10 5 kyr bp making them the oldest holocene reefs known in australia reef growth persisted for 2 0 kyr but it had ceased at most locations by 7 0 kyr bp measurements of reef growth rates 0 95 to 4 m kyr 1 indicate that the reefs were unable to keep pace with contemporaneous rapid sea level rise 10 m kyr 1 which is consistent with a give up reef growth history core samples from reef platforms demonstrate that pleistocene limestone is exposed at depths of 27 and 30 m below present mean sea level these depths represent regionally significant phases of reef growth during a prolonged sea level still stand we conclude that the reefs are therefore mostly relict features whose major phase of growth and development relates to an earlier pre holocene sea level still stand

an open system model for u series age determinations of fossil corals the source of excess 234u in fossil corals and its relationship to u series age determinations has been an outstanding problem in geochronology for more than 20 years with increasing numbers of u series isotope measurements in corals and significant improvements in analytical precision through mass spectrometry it is increasingly apparent that a substantial fraction of observed isotope ratios cannot be reasonably explained by closed system decay moreover observations of a positive correlation between 234u 238u and 230th 238u ratios in corals from the same terrace are difficult to explain however the decay of dissolved uranium and recoil mobilization of uranium daughters produce particle reactive 234th and 230th and the coupled addition of these th isotopes could simultaneously increase coral 234u 238u and 230th 238u here we present a quantitative model based on decay dependent redistribution of 234th and 230th permitting calculation of open system coral ages these equations provide a general solution to the recoil redistribution problem applicable to any alpha decay series while measured isotope ratios of corals from the three youngest stratigraphically defined barbados terraces are inconsistent with closed system decay they fall in broadly linear arrays agreeing with model predictions isotopic arrays of older barbados corals and corals from terraces around the world are also consistent with model predictions suggesting the open system model is generally applicable corals with extreme isotopic compositions that are impossible to produce by closed system decay are consistent with the limited range of isotopic compositions predicted by the model at ages older than 600 ka for corals from a single terrace 234th and 230th redistribution appears to be a source of systematic conventional age error even for corals with slightly elevated 234u however open system ages are consistent even for corals with extremely elevated 234u for the youngest three barbados terraces mean open system terrace ages are consistent with mean conventional terrace ages calculated from pristine samples if the most accurate conventional ages are from corals with an initial 234u 238u identical to modern seawater then the open system model will improve the accuracy of coral u series age determinations and dramatically increase the number of reliable ages

hydraulics of embankment weirs embankment weirs often found in engineering applications with a side slope 1v 2h are considered in this paper for free overflow the discharge coefficient is determined in terms of relative crest length for long broad crested broad crested short crested and thin crested weirs a considerable increase of capacity is noted when compared to broad crested weirs with vertical face for submerged overflow four regimes are identified 1 a jump 2 plunging jet 3 surface wave and 4 surface jet particular attention is focused on plunging jets and surface waves the flow regimes are discussed in terms of submergence crest length and modular limit a description is given of the forward and backward recirculation zones with indications of typical lengths also the entire velocity field is described including the maximum forward and backward velocities and the velocity distribution in arbitrary sections of the tailwater region it is found that plunging jets and surface jets are hydraulically similar and that the profile of one regime can be transformed into the other profile by inversion about the median all results are generalized and can be directly applied

reef drowning during the last deglaciation evidence for catastrophic sea level rise and ice sheet collapse elevations and ages of drowned acropora palmata reefs from the caribbean atlantic region document three catastrophic metre scale sea level rise events during the last deglaciation these catastrophic rises were synchronous with 1 collapse of the laurentide and antarctic ice sheets 2 dramatic reorganization of ocean atmosphere circulation and 3 releases of huge volumes of subglacial and proglacial meltwater this correlation suggests that release of stored meltwater periodically destabilized ice sheets causing them to collapse and send huge fleets of icebergs into the atlantic massive inputs of ice not only produced catastrophic sea level rise drowning reefs and destabilizing other ice sheets but also rapidly reduced the elevation of the laurentide ice sheet flipping atmospheric circulation patterns and forcing warm equatorial waters into the frigid north atlantic such dramatic evidence of catastrophic climate and sea level change during deglaciation has potentially disastrous implications for the future especially as the stability of remaining ice sheets such as in west antarctica is in question

tsunami hazard assessment in the hudson river estuary based on dynamic tsunami tide simulations this work is part of a tsunami inundation mapping activity carried out along the us east coast since 2010 under the auspice of the national tsunami hazard mitigation program nthmp the us east coast features two main estuaries with significant tidal forcing which are bordered by numerous critical facilities power plants major harbors as well as densely built low level areas chesapeake bay and the hudson river estuary hre hre is the object of this work with specific focus on assessing tsunami hazard in manhattan the hudson and east river areas in the nthmp work inundation maps are computed as envelopes of maximum surface elevation along the coast and inland by simulating the impact of selected probable maximum tsunamis pmt in the atlantic ocean margin and basin at present such simulations assume a static reference level near shore equal to the local mean high water mhw level here instead we simulate maximum inundation in the hre resulting from dynamic interactions between the incident pmts and a tide which is calibrated to achieve mhw at its maximum level to identify conditions leading to maximum tsunami inundation each pmt is simulated for four different phases of the tide and results are compared to those obtained for a static reference level we first separately simulate the tide and the three pmts that were found to be most significant for the hre these are caused by 1 a flank collapse of the cumbre vieja volcano cvv in the canary islands with a 80 km3 volume representing the most likely extreme scenario 2 an m9 coseismic source in the puerto rico trench prt and 3 a large submarine mass failure smf in the hudson river canyon of parameters similar to the 165 km3 historical currituck slide which is used as a local proxy for the maximum possible smf simulations are performed with the nonlinear and dispersive long wave model funwave tvd in a series of nested grids of increasing resolution towards the coast by one way coupling four levels of nested grids are used from a 1 arc min spherical coordinate grid in the deep ocean down to a 39 m cartesian grid in the hre bottom friction coefficients in the finer grids are calibrated for the tide to achieve the local spatially averaged mhw level at high tide in the hre combined tsunami tide simulations are then performed for four phases of the tide corresponding to each tsunami arriving at sandy hook nj 1 5 h ahead concurrent with 1 5 h after and 3 h after the local high tide these simulations are forced along the offshore boundary of the third level grid by linearly superposing time series of surface elevation and horizontal currents of the calibrated tide and each tsunami wave train this is done in deep enough water for a linear superposition to be accurate combined tsunami tide simulations are then performed with funwave tvd in this and the finest nested grids results show that for the 3 pmts depending on the tide phase the dynamic simulations lead to no or to a slightly increased inundation in the hre by up to 0 15 m depending on location and to larger currents than for the simulations over a static level the crt smf proxy tsunami is the pmt leading to maximum inundation in the hre for all tide phases nonlinear interactions between tide and tsunami currents modify the elevation current and celerity of tsunami wave trains mostly in the shallower water areas of the hre where bottom friction dominates as compared to a linear superposition of wave elevations and currents we note that while dynamic simulations predict a slight increase in inundation this increase may be on the same order as or even less than sources of uncertainty in the modeling of tsunami sources such as their initial water elevation and in bottom friction and bathymetry used in tsunami grids nevertheless results in this paper provide insight into the magnitude and spatial variability of tsunami propagation and impact in the complex inland waterways surrounding new york city and of their modification by dynamic tidal effects we conclude that changes in inundation resulting from the inclusion of a dynamic tide in the specific case of the hre although of scientific interest are not significant for tsunami hazard assessment and that the standard approach of specifying a static reference level equal to mhw is conservative however in other estuaries with similarly complex bathymetry topography and stronger tidal currents a simplified static approach might not be appropriate

reworking processes and deposits in coral reefs during very high energy events example from a pleistocene coral formation 125 ka la desirade island lesser antilles abstract abundant literature has documented the ecological impact of very high energy hurricane type events and high energy storm type events on modern coral reefs and sediment transport in previous studies sedimentary processes are often deduced from geophysical image analysis and scuba diving observations few field based studies have been devoted to the impact of very high energy disturbance on the structure and ecology of holocene and pleistocene coral reefs and very few to the sedimentary processes acting around these reefs this research examines the structure of the late pleistocene end of mis5e stage reefs of la desirade island guadeloupe archipelago lesser antilles and focuses on the poorly known reworking processes and related coral breccia sedimentation surrounding these reefs fieldwork was performed to document two coral fragment rich breccia interbedded with coral patches the breccia predominantly show the same petrography but differ in their internal structure showing a massive breccia type and a stratified breccia type this work infers that these breccia are the result of gravity induced high density mass flows triggered by high to very high energy events such as storms and hurricanes damage and reworking vary according to the type of very high energy event prior to transport storms are thought to have broken the heads of branching and columnar coral colonies and broken and overturn isolated lamellar and massive colonies hurricanes particularly their eye walls may have reworked much more sediment than storms and may have also destabilised entire several metre sized columnar colonies from the flank of coral patch reefs we propose the name coral debrite for these coral breccia deposits caused by gravity induced debris flows the reworked deposits are interbedded between two coral reef levels of which the main coral species vertical succession should record the end of marine isotope stage 5e sea level rise thus reworking is believed to occur during the transitional stage between a glacial and an interglacial period

chronostratigraphy and geomorphology of washover fans in the exmouth gulf nw australia a record of tropical cyclone activity during the late holocene abstract washover fans typically form due to barrier overwash or breaching and coastal inundation and generally represent geomorphological and depositional evidence of intense storms few studies have investigated the chronostratigraphy of washover fans in order to infer magnitude frequency patterns of extreme wave events over longer time scales here we present new data on the chronostratigraphy of late holocene washover fans in the exmouth gulf western australia by using ground penetrating radar and unmanned aerial vehicle uav survey techniques as well as geomorphological sedimentological and chronological investigations this study aims to i provide a detailed characterization of the washover fans geomorphology and stratigraphical architecture ii document depositional processes involved in their formation iii establish a chronostratigraphy based on optically stimulated luminescence osl and iv understand the significance of the washover fans for recording past tropical cyclone tc activity the fans consist of multiple sequences of sand shell debris and coral rubble comprising depositional units related to tc induced inundation the units are separated by palaeosurfaces with incipient soil formation formed during periods of reduced depositional activity in combination with the interpretation of a uav based high resolution digital surface model multiple phases of reactivation are inferred osl results allow the establishment of a local long term tc record and suggest storm induced deposition at 170 360 850 and 1300 years ago further units were dated to 1950 2300 and 2850 years ago the chronology of tc events is consistent with other work relating tc activity with el nino southern oscillation enso and sea surface temperature sst patterns corroborating the regional palaeotempestological relevance of this unique geomorphological record

fringing reef growth and morphology a review abstract fringing reefs are generally not simple veneers of coral growth along tropical shorelines extensive research over the past few decades based on radiocarbon dating of holocene reef deposits has indicated that they can develop in a complex variety of ways even though the surface morphology may appear relatively simple the principal factor that appears to determine the growth and morphology of fringing reefs is the available accommodation space sea level fluctuations are important primarily because the sea surface determines the absolute accommodation space for a given reef this means that a reef established during a period of sea level rise will be able to accrete vertically as space is created above it if however the reef establishes at or grows to the sea surface thereby occupying all the available accommodation space it can no longer accrete vertically and begins to build laterally the morphology and chronostratigraphy of a range of holocene fringing reefs are described on the basis of which six fringing reef growth models are identified in model a the fringing reef is established at depth and primarily accretes vertically towards the sea surface reef growth in model b initiates at sea level and due to the lack of vertical accommodation space grows laterally model c has a similar morphology to model b however the reef progrades over a non reefal sediment wedge episodic lateral and vertical growth occurs in model d with a stepwise progradation of the reef front the remaining models are characterised by seaward reef framework behind which unconsolidated sediments accumulate in model e reef crest growth forms a barrier leading to the development of a backreef lagoon model f has a similar morphology to model e except that the reef crest is formed by hurricane rubble accumulation rather than framework accretion and is periodically reworked

freshwater outbursts to the oceans from glacial lake agassiz and their role in climate change during the last deglaciation abstract lake agassiz was the largest lake in north america during the last deglaciation as the laurentide ice sheet lis retreated large volumes of water stored in this proglacial lake were episodically released into the oceans these waters were variably routed to the gulf of mexico arctic ocean north atlantic ocean and hudson bay during this period the three largest cooling events in the northern hemisphere closely followed 4 of the 5 largest outbursts from lake agassiz 1 the younger dryas which was preceded by a release of 9500 km 3 2 the preboreal oscillation preceded by releases of 9300 km 3 and 5900 km 3 and 3 the 8 2 ka cold event preceded by a 163 000 km 3 outburst these are respectively fluxes of 0 30 sv 0 29 sv 0 19 sv and 5 2 sv if released in 1 year because the influx of freshwater reaching the north atlantic ocean can inhibit thermohaline circulation partly depending on whether the ocean was in a glacial interglacial or transitional mode of circulation we believe that at least these large outbursts from lake agassiz may have provided the triggers for changes in ocean circulation and in turn for widespread climate change

experimental investigation of tsunami bore impact force and pressure on a square prism abstract the 2004 indian ocean tsunami and the recent 2011 japan tsunami have highlighted the need to investigate the interaction between tsunamis and coastal structures although some efforts have been made to determine tsunami loads on structures there are discrepancies between the limited number of published design guidelines this study comprises an experimental investigation of a tsunami bore interaction with an inland structure physical modelling of the tsunami bore in the laboratory allowed study of the impact of tsunami bores on a square prism model having different orientations to the flow direction the use of common geometrical shapes simplifies experiments and increases the reliability of results the experiments were conducted in a 14 m long 1 2 m wide and 0 8 m deep wave flume equipped with an automatic gate designed to generate a tsunami bore measurements were made of the forces and pressures exerted on the model structure and of the bore heights and velocities the vertical pressure distribution was measured on what was initially the structure s front wall with the front wall at 0 30 45 60 90 and 135 to its original alignment a relation between bore velocity and bore height is presented the measured maximum forces in the stream wise and upward directions were numerically modelled successfully and relevant drag coefficients were determined for the structure at different orientations

fault parameters of the 1896 sanriku tsunami earthquake estimated from tsunami numerical modeling the june 15 1896 sanriku earthquake generated devastating tsunamis with the maximum run up of 25 m and caused the worst tsunami disaster in the history of japan despite its moderate surface wave magnitude ms 7 2 and weak seismic intensity this is a typical tsunami earthquake which generates anomalously larger tsunamis than expected from its seismic waves previously proposed mechanisms of tsunami earthquakes include submarine slumping and slow rupture in the accretionary wedge or in the subducted sediments in this paper we estimate the fault parameters of the 1896 tsunami earthquake by numerically computing the tsunami and comparing the waveforms with those recorded at three tide gauge stations in japan the result indicates that the tsunami source is very close to the japan trench and the fault strike is parallel to the trench axis the fault width is about 50 km suggesting that the tsunami earthquake is a slow rupture in the subducted sediments beneath the accretionary wedge

the evolution of the meliata hallstatt ocean and its significance for the early evolution of the eastern alps and western carpathians abstract the evolution of the meliata hallstatt ocean and of its southern and northern margin in the inner western carpathians are described the main rifting began during the pelsonian and the sea floor spreading ended at the beginning of the middle carnian contemporaneously with the raibl event the subduction began in the latest triassic and the final closing of the ocean accompanied by uplift of the adjacent marginal areas was dated as basal oxfordian remnants of the oceanic suboceanic sequence occur in two tectonic positions 1 obducted nappes that contain mostly as tectonic melanges the whole middle triassic to middle jurassic sequence including large bodies of dismembered ophiolites of ladinian to early carnian age 2 evaporite melanges at the base of nappes that are derived from the northern margin of the ocean these evaporite melanges consist of late permian evaporitic matrix and blocks of a dismembered ladinian to lower carnian ophiolitic sequence in the inner western carpathians both the northern and southern marginal sequences of the meliata hallstatt ocean and the transitions into the carbonate platforms are present in different nappes the southern marginal development is characterized by middle carnian distal clastic raibl beds and by middle jurassic rhyolithic volcanism both missing in the northern marginal development because the subduction related middle jurassic volcanism contemporaneous with the turbidites in the southern meliaticum is restricted to the marginal area south of the meliata hallstatt ocean southward directed subduction is indicated to the south on the adjacent carbonate platform a jurassic basin with aalenian to bajocian ophiolites opened this may be a back arc basin in the eastern alps only the northern marginal zone and the adjacent carbonate platform are preserved but parts of the dismembered ophiolites in the haselgebirge may be of ladinian to late carnian age like in evaporitic melanges in the same tectonic position in the inner western carpathians the final closing of the meliata hallstatt ocean is indicated by the abrupt end of the turbiditic sedimentntation in the oceanic suboceanic domain and by uplift in the marginal areas where lower oxfordian radiolarites are overlain by shallow water upper oxfordian to tithonian or neocomian limestones silica nappe hallstatt nappes with the evidence of the final closing of the meliata hallstatt ocean near the middle late jurassic boundary the cimmerian orogenesis in the genetic sense of engor 1984 1985 is now also proven in the inner western carpathians and in the eastern alps a continuation of the meliata hallstatt ocean into the pontide paleotethys cimmerian ocean sensu kozur 1990 through the transylbanian oceanic domain and the strandzha unit is assumed a connecction with the vardar ocean is impossible because in the vardar zone no triassic ophiolites or basic volcanics are present and the ophiolites have jurassic age

comparison of inundation depth and momentum flux based fragilities for probabilistic tsunami damage assessment and uncertainty analysis abstract annual exceedance probabilities of the maximum tsunami inundation depth hmax and momentum flux mmax conditional on a full rupture event of the cascadia subduction zone csz were used to estimate the probability of building damage using a fragility analysis at seaside oregon tax lot data google street view and field reconnaissance surveys were used to classify the buildings in seaside and to correlate building typologies with existing fragility curves according to the construction material number of stories and building seismic design level based on the date of construction a fragility analysis was used to estimate the damage probability of buildings for 500 1000 and 2500 year exceedance probabilities conditioned on a full rupture csz event finally the sensitivity of building damage was estimated for both the aleatory and epistemic uncertainties involved in the process of damage estimation probable damage estimates from the fragility curves based on hmax and on mmax both generally show higher damage probability for structures that are wooden and closer to the shoreline than those that are reinforced concrete rc and further landward of the shoreline however a relatively high and somewhat unrealistic damage probability was found at the river and creek region from the fragility curve analysis using hmax within 500 m from the shoreline wood structure damage shows significant sensitivity to the aleatory uncertainty of the tsunami generation from the csz event on the other hand rc structure damage showed equal sensitivity to the aleatory uncertainty of the tsunami generation as well as the epistemic uncertainties due to the numerical modeling of the tsunami inundation friction the building classification material and date of construction and the type of fragility curves depth or momentum flux type curves further from the shoreline the wood structures showed similar aleatory and epistemic uncertainties qualitatively similar to the rc structure sensitivity closer to the shoreline

holocene sea level determination relative to the australian continent u th tims and 14c ams dating of coral cores from the abrolhos islands u th tims and 14 c ams measurements are presented from two coral cores from the easter group of the houtman abrolhos islands between 28 s and 29 s on the western continental margin of australia the u th measurements on the morley core from morley island cover a depth interval from 0 2 m above present sea level to 24 4 m below present sea level and comprise eleven samples the ages vary between 6320 50 a at 0 2 m above sea level and 9809 95 a at 24 4 m below sea level all errors are 2 the mean growth rate is 7 1 0 9 m ka the 14 c dates of selected morley core corals show that the 14 c ages are 1000 a younger than their corresponding u th ages which agrees with previous results the main purpose of our 14 c measurements is to be able to compare them precisely with other coral cores where no u th measurements are available the u th measurements of the suomi core from suomi island cover a depth interval from 0 05 m to 14 2 m below present sea level and consist of four samples the ages vary between 4671 40 a at 0 05 m below sea level and 7102 82 a at 14 2 m below sea level with a mean growth rate of 5 8 0 2 m ka the growth history of both cores is explained by a simple model in which the growth rates of the morley core can be interpreted as reflecting local rates of sea level rise whereas the suomi core is interpreted as reflecting lateral growth during the past 6000 a our results indicate that sea level relative to the western margins of the australian continent was about 24 m lower than present at about 9800 a b p 14 c gives a date of 8500 a b p sea level then rose and reached a highstand slightly higher than the present position at about 6300 a b p 14c date 5500 a this highstand declined but was still higher than present at 4600 a b p this is in agreement with previous observations along the australian coastal margins and with observations from the huon peninsula papua new guinea our results are very similar to theoretical numerical models which take into consideration water loading and isostatic compensation and viscous mantle flow in contrast coral cores from barbados show that corals with a 14 c age of 5500 a b p are some 10 m b p s l we interpret the difference between the barbados core and the morley core as resulting from additional flooding of barbados by water redistribution due to changes in the earth s geoid but not reflecting global sea level rise or major addition of melt waters over the past 6000 a the difference in the geoid at barbados between 6000 a b p and the present will require a refinement in the geophysical models precise 230 th tims measurements on continental coasts will be required to provide an adequate data base for modelling deformation flow of mantle material and sea level height

traces of historical tropical cyclones and tsunamis in the ashburton delta north west australia although the north western coast of western australia is highly vulnerable to tropical cyclones and tsunamis little is known about the geological imprint of historic and prehistoric extreme wave events in this particular area despite a number of site specific difficulties such as post depositional changes and the preservation potential of event deposits both tropical cyclones and tsunamis may be inferred from the geomorphology and the stratigraphy of beach ridge sequences washover fans and coastal lagoons or marshes a further challenge is the differentiation between tsunami and storm deposits in the geological record particularly where modern deposits and or historical reports on the event are not available this study presents a high resolution sedimentary record of washover events from the ashburton river delta western australia spanning approximately the last 150 years a detailed characterization of event deposits is provided and a robust chronostratigraphy for the investigated washover sequence is established based on multi proxy sediment analyses and optically stimulated luminescence dating combining sedimentological geochemical and high resolution optically stimulated luminescence data event layers are assigned to known historical events and tropical cyclone deposits are separated from tsunami deposits for the first time the 1883 krakatoa and 1977 sumba tsunamis are inferred from sedimentary records of the north western part of western australia it is demonstrated that optically stimulated luminescence applied in coastal sedimentary archives with favourable luminescence characteristics can provide accurate chronostratigraphies even on a decadal timescale the results contribute to the data pool of tropical cyclone and tsunami deposits in holocene stratigraphies however they also demonstrate how short lived sediment archives may be in dynamic sedimentary environments

the 2011 japan tsunami current velocity measurements from survivor videos at kesennuma bay using lidar 1 on march 11 2011 a magnitude mw 9 0 earthquake occurred off the coast of japan s tohoku region causing catastrophic damage and loss of life the tsunami flow velocity analysis focused on two survivor videos recorded from building rooftops at kesennuma bay along japan s sanriku coast a terrestrial laser scanner was deployed at the locations of the tsunami eyewitness video recordings the tsunami current velocities through the kesennuma bay are determined in a four step process the lidar point clouds are used to calibrate the camera fields of view in real world coordinates the motion of the camera during recordings was determined the video images were rectified with direct linear transformation finally a cross correlation based particle image velocimetry analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields the measured maximum tsunami height of 9 m in the kesennuma bay narrows were followed by maximum tsunami outflow currents of 11 m s less than 10 minutes later

propagation and amplification of tsunamis at coastal boundaries when tsunamis hit a coastal area they often cause substantial damage and loss of life at locations otherwise well protected from normal even severe wind generated waves an example of such a catastrophe took place on 12 december 1992 when an earthquake of magnitude ms 7 5 occurred in the eastern region of flores island indonesia1 2 one of the areas hardest hit by the resulting tsunamis was babi a small coastal island two villages on the island were completely destroyed even though both were located in sheltered areas where wave conditions are normally calm here we describe the results of numerical and laboratory experiments that show how unlike wind generated waves tsunamis are capable of penetrating into sheltered coastal areas without significantly losing their energy for the case of babi island the original tsunami wave was split into two with one wave propagating around each side of the island the two waves met in the sheltered region and the subsequent amplification of wave amplitude resulted in the destructive flow onto the beach

empirical building fragilities from observed damage in the 2009 south pacific tsunami abstract this manuscript presents empirical building fragility functions that were developed based on data obtained from the 29th september 2009 south pacific tsunami a multi disciplinary reconnaissance team involving topographic surveyors tsunami hydrology modellers structural engineers and risk analysts collected observational and quantitative data on building damage and the tsunami demand a diverse range of collected data which included a topographic survey observed water depths predominant flow directions inundation limits building damage and eyewitness reports were used to recreate the peak tsunami induced demands on structures at each of the survey locations using the interpreted data fragility functions were developed for a variety of building classes using logistic regression it was observed that residential timber structures were more fragile i e have a higher likelihood of damage for a given water depth than masonry residential structures for severe and collapse damage states conversely residential reinforced concrete structures were observed to be less fragile than residential masonry structures for severe and collapse damage states the influence of shielding and entrained debris effects on fragility functions were also quantified using the empirical data other parameters such as velocity or impact duration were not considered due to the paucity of data the results of this study contribute to the ongoing development of robust methods for explicitly estimating tsunami induced risk to coastal communities

significance of shallow core transects for reef models and sea level curves heron reef great barrier reef a sequence of shallow reef cores from heron reef great barrier reef provides new insights into holocene reef growth models isochron analysis of a leeward core transect suggests that the north western end of heron reef reached current sea level by ca 6 5 kyr bp and then prograded leeward at a rate of ca 19 6 m kyr between 5 1 kyr and 4 1 kyr bp pre 1950 to the present reef margin a single short core on the opposing margin of the reef is consistent with greater and more recent progradation there further to the east one windward core reached modern sea level by ca 6 3 kyr bp suggesting near keep up behaviour at that location but the opposing leeward margin behind the lagoon reached sea level much more recently hence heron reef exhibited significantly different reef growth behaviour on different parts of the same margin mean reef accretion rates calculated from within 20 m of one another in the leeward core transect varied between ca 2 9 m and 4 7 m kyr depending on relative position in the prograding wedge these cores serve as a warning regarding the use of isolated cores to inform reef growth rates because apparent aggradation at any given location on a reef varies depending on its location relative to a prograding margin only transects of closely spaced cores can document reef behaviour adequately so as to inform reef growth models and sea level curves the cores also emphasize potential problems in u series dates for corals within a shallow ca 1 5 m zone beneath the reef flat apparent age inversions restricted to that active diagenetic zone may reflect remobilization and concentration of th in irregularly distributed microbialites or biofilms that were missed during sample vetting importantly the th containing contaminant causes ages to appear too old rather than too young as would be expected from younger cement

quantification of swash flows using video based particle image velocimetry understanding of fluid flows and sediment transport in the foreshore has been severely hampered by the difficulty of obtaining swash flow velocity measurements in this dynamic and extremely shallow region we present a digital imaging method known as particle image velocimetry piv to quantify the horizontal flow structure of swash this technique exploits similar patterns of image intensity in multiple images sampled sequentially to identify spatial offsets corresponding with maximum correlations between image subregions these offsets are used in conjunction with the sampling interval to derive velocity vectors describing the horizontal flow structure pre processing methods to geo rectify oblique imagery to a planar surface and post processing methods of correcting spurious vectors are described the piv method overcomes many of the limitations of in situ sampling of swash flows and is shown consistent with results from a previously tested remote sensing technique for measuring swash edge velocities in general this technique provides a unique capability for spatially extensive and well resolved quantification of swash flows

postglacial sea level changes in the northern south china sea continental shelf evidence for a post 8200 calendar yr bp meltwater pulse abstract a postglacial sea level record reconstructed through the study of 25 cores and 10 grab samples obtained from the siliciclastic dominated northern south china sea continental shelf between hong kong and dongsha is presented the seven sedimentary facies recognized are 1 pleistocene overconsolidated mud facies affected by palaeosol development due to sub aerial exposure during the last glacial maximum lgm 2 bioclastic sandy gravel facies occurring at a present day seabed depth exceeding 120 m 3 lgm bioclastic beach dune sand facies at a present day seabed depth between 110 and 120 m 4 postglacial siliciclastic beach dune sand facies formed during at least two episodes of sea level stillstands at present day seabed depths between 80 and 90 m and 30 and 50 m respectively 5 postglacial transgressive sand facies of late pleistocene to early holocene age radiocarbon dating shows that this facies was deposited in two stages before and after the 8200 calendar yr bp cold event 6 postglacial sand and gravel dominated facies with acoustic turbidity at a present day seabed depth of about 50 m 7 postglacial mud facies based on the radiocarbon ages obtained from samples located above and below the holocene pleistocene hiatus in the two innermost shelf cores and large variations of atmospheric radiocarbon concentration found during the last glacial period in a submerged stalagmite from the bahamas beck et al 2001 science 292 2453 2458 ages exceeding 8200 calendar yr bp are likely to represent minimum values ages postdating this limit which are less affected by variations of atmospheric radiocarbon concentration indicate the presence of a post 8200 calendar yr bp cold event meltwater pulse caused by eustatic sea level rise from approximately 40 m below present to the present level by about 6000 calendar yr bp inaccuracies of the pre 8200 calendar yr bp radiocarbon ages may be attributed to large variations of atmospheric 14 c during the postglacial period with greenhouse gases released from the sub aerially exposed continental shelf probably accounting for a significant proportion

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

are catch up reefs an artefact of coring drill cores through modern coral reefs commonly show a time lag in reef initiation followed by a phase of rapid accretion to sea level from submerged foundations the so called catch up response but because of the difficulty of drilling in these environments core distribution is usually restricted to accessible areas that may not fully represent reef history especially if the reef initiated in patches or developed with a prograde or retrograde geometry as a consequence core data have the potential to give a misleading impression of reef development particularly with respect to the timing of initiation and response to sea level rise here we use computer models to simulate keep up reef development and from them quantify variations in the timing of reef initiation and accretion rate using mock cores taken through the completed simulations the results demonstrate that cores consistently underestimate the timing of reef initiation and overestimate the reef accretion rate so that statistically a core through a keep up reef will most likely produce a catch up pattern an initiation lag followed by a phase of rapid accretion to sea level this implies that catch up signatures may be an artefact of coring and that keep up reefs are significantly more common than previous core studies claim

2004 indian ocean tsunami flow velocity measurements from survivor videos 1 the tsunami of 26th december 2004 severely affected banda aceh along the north tip of sumatra indonesia at a distance of 250 km from the epicenter of the magnitude 9 0 earthquake this tsunami flow velocity analysis focused on two survivor videos recorded within banda aceh more than 3 km from the open ocean the exact locations of the tsunami eyewitness video recordings were revisited by the survey team between february 22 and 25 2005 to record camera calibration ground control points the motion of the camera during the recordings was determined the individual video images were rectified with a direct linear transformation dlt assuming a planar water surface at the level finally a cross correlation based particle image velocimetry piv analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields the measured tsunami flow velocities were within the range of 2 to 5 m s

growth history of shallow water carbonates control of accommodation on ecological and depositional processes we explore the role played on the growth of shallow water carbonates by changes in accommodation using case studies from late quaternary to modern carbonate environments i e coral reefs and carbonate platforms and ramps accommodation appears not to influence either primary productivity or community structure k versus r strategists as these are directly governed by nutrient supply but it does control submarine depositional profiles and their stratigraphic expression i e volumetric sedimentary partitioning the growth of communities from incipient to senescent stages is dictated by relative rates of sea level variations although ambient temperatures and trophic conditions may modify the community response a decrease or stabilization of accommodation favours lateral migration thus generating ecological and sedimentary innovations organic carbon production tends to be positively correlated to that of carbonate both declining as accommodation decreases shallow water carbonates develop as a result of the interplay of factors including the types and rates of biological and physical processes applying depositional models of recent shallow water carbonates to the interpretation of ancient carbonate platforms first needs to acknowledge the respective role of the two contrasting phases that operated during the post glacial sea level rise an earlier fast rising phase versus a later slowly rising to stabilizing phase the period of relative sea level stabilization i e the past 6 000 years appears a relevant reference for still stand related carbonate systems furthermore the oligotrophic nutrient model a dominant feature of the modern shallow water tropics can be used as an analogue in reconstructing carbonate growth histories during greenhouse episodes of earth history

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

survey of 2011 tohoku earthquake tsunami inundation and run up 1 at 14 46 local time on march 11 2011 a magnitude 9 0 earthquake occurred off the coast of northeast japan this earthquake generated a tsunami that struck japan as well as various locations around the pacific ocean with the participation of researchers from throughout japan joint research groups conducted a tsunami survey along a 2000 km stretch of the japanese coast more than 5300 locations have been surveyed to date generating the largest tsunami survey dataset in the world on the sendai plain the maximum inundation height was 19 5 m and the tsunami bore propagated more than 5 km inland along the ria coast from about 50 to 200 km north of sendai the narrow bays focused the tsunami waves generating the largest inundation heights and run ups the survey data clearly show a regional dependence of tsunami characteristics

significance of late permian triassic facies zones in terrane reconstructions in the alpine north pannonian domain abstract the present day setting of the tectonic units terranes making up the pre neogene basement of the pannonian basin and the west carpathians is the result of large scale displacements during the alpine collisional phases to explain this setting based on various concepts a number of models have been proposed in the last decade most of them agree in an eastward escape of the north pannonian terrane from the alpine domain towards the pannonian during the palaeogene early miocene period in the present paper a reconstruction of the pre escape setting of the displaced terranes is presented based on facies zones in selected time slices from the late permian to the late triassic according to our reconstruction the inner west carpathian units were located east of the austroalpine units forming the northern shelf of the euhallstatt meliatic basin of the vardar oceanic branch the drauzug should have been located in a position much more external than its present day setting the transdanubian range was situated in the northern neighbourhood of the southern alps whereas the bukk may have been located adjacent to the nw dinarides the mid transdanubian zone is a major shear zone containing elements of the julian alps and sava folds nappe system and the inner dinaric ophiolitic melange although the nappe tectonism may have played an important role in the structural evolution of the north pannonian terrane this mechanism alone can hardly produce hundreds of kilometres of facies offset on the opposite sides of strike slip zones

experimental study of uplift loads due to tsunami bore impact on a wharf model abstract tsunamis are unpredictable disasters that have occurred frequently in recent years an experimental study was conducted to quantify the tsunami bore uplift loads on a deck mounted on a slope representing a typical wharf structure tsunami bores were generated as dam break waves in a flume and the bore froude number was approximately 1 6 on the dry bed fifty five tests 11 bore cases 5 runs each cases were conducted for detailed measurements of bore height and bore velocity and 504 tests 7 bore cases 3 deck heights 8 wharf slope angles 3 runs each combination were conducted for measurements of time histories of pressure on the soffit of the deck the effects of bore height deck height and slope angle on uplift loads were studied results show that bore height correlates with bore velocity the flow motion of the tsunami bore impacting the deck is divided into five stages front climbing front hitting run up quasi steady and recession the uplift pressure decreases from the deck slope connection to the deck front edge and the total uplift load increases with increasing bore height or decreasing deck height for the front hitting stage the maximum pressure the uplift load increases as the wharf slope angle decreases however for the quasi steady stage the longest time period the uplift load is consistent for different wharf slope angles based on the experimental data the equations for predicting the front hitting and quasi steady pressures are proposed as functions of bore height deck height and wharf slope angle and the predicted values are within 20 error

quantitative tsunami risk assessment in terms of building replacement cost based on tsunami modelling and gis methods the case of crete isl hellenic arc tsunami risk assessment is an important component of the planning for risk reduction we considered tsunami risk as a convolution of tsunami hazard vulnerability of the assets at risk e g buildings and the economic value exposed for testing the model a coastal segment at the west of heraklion capital city of crete isl greece was selected heraklion was hit in the past by strong tectonic and volcanic tsunamis generated along the hellenic arc in the mediterranean region the minoan tsunami produced by pyroclastic flows during the lba 17th century bc great eruption of thera santorini was selected as an extreme tsunami scenario for the hazard inundation zone determination through numerical simulation based on boussinesq equations for fully non linear waves it was found that the wave penetrates inland up to 1 2 km while the maximum water depth is 14 m the building stock was obtained from the 2011 national census data and validated with the use of orthophotomaps field inspection and google maps building vulnerability was determined with the use of the empirical gis tool damasche which is based on 2004 indian ocean tsunami building damage data and produces damage level by combining water depth and building construction types the damage level was translated to absolute monetary loss on the basis of cost flat rates determined officially for building replacement i e either reparation or reconstruction after the destructive earthquakes in greece during 2014 the method is applicable in other parts of the mediterranean and beyond provided that appropriate data are available

lituya bay landslide impact generated mega tsunami 50th anniversary on july 10 1958 an earthquake mw 8 3 along the fairweather fault triggered a major subaerial landslide into gilbert inlet at the head of lituya bay on the southern coast of alaska the landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history the mega tsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis a cross section of gilbert inlet was rebuilt at 1 675 scale in a two dimensional physical laboratory model based on the generalized froude similarity a pneumatic landslide tsunami generator was used to generate a high speed granular slide with controlled impact characteristics state of the art laser measurement techniques such as particle image velocimetry piv and laser distance sensors lds were applied to the decisive initial phase with landslide impact and wave generation as well as the runup on the headland piv provided instantaneous velocity vector fields in a large area of interest and gave insight into kinematics of wave generation and runup the entire process of a high speed granular landslide impact may be subdivided into two main stages a landslide impact and penetration with flow separation cavity formation and wave generation and b air cavity collapse with landslide run out and debris detrainment causing massive phase mixing formation of a large air cavity similar to an asteroid impact in the back of the landslide is highlighted a three dimenional pneumatic landslide tsunami generator was designed constructed and successfully deployed in the tsunami wave basin at osu the lituya bay landslide was reproduced in a three dimensional physical model at 1 400 scale the landslide surface velocities distribution was measured with piv the measured tsunami amplitude and runup heights serve as benchmark for analytical and numerical models

discovery of a submerged relic reef and shoreline off grand cayman further support for an early holocene jump in sea level abstract drilling close to the base of a submerged sea cliff on the terraced eastern shelf of grand cayman has revealed a relic acropora palmata reef at a depth of 21 m below msl ten cores from its crest are principally composed of cobble sized clasts of a palmata set in a matrix of cemented skeletal grainstone the clasts have a distinctive succession of encrusters that indicate rapid burial a photophilic association of crustose coralline algae foraminifera and vermetid gastropods superimposed by a cryptic association of sclerosponges foraminifera and serpulids in addition to rapid burial u th thermal ionization mass spectrometer tims dating of coral clasts within 1 m of the relic reef surface indicates minor temporal mixing with ages between 8 9 and 8 1 ka such mixing and rapid burial is consistent with a hurricane deposit and is identical to deposits found on the crests of modern reefs in relation to its age the preservation of a 18 5 m intertidal notch cut into the submerged sea cliff on the western shelf of grand cayman implies that the crest of the relic reef has been lowered 1 5 2 m by marine abrasion bioerosion at a rate of 0 25 mm yr 1 reconstructing this eroded section using average holocene accretion rates indicates that the reef likely ceased accreting at 7 6 ka at a depth of 19 m comparing these data with other relic reefs in the caribbean indicates that the relic reef on grand cayman died within 160 years of relic reefs on barbados st croix st thomas and north florida this narrow interval of reef demise also coincides with the time when modern reefs were establishing themselves some 4 9 m higher upslope a fact that can only be resolved by invoking a rapid 6 m jump in sea level 7 5 ka ago such a jump would also account for two unexplained events around this time the restricted interval of global delta initiation and the catastrophic flooding of the glacially lowered black sea

an inflection in the rate of early mid holocene eustatic sea level rise a new sea level curve from singapore this study presents a sea level curve from 9500 to 6500 cal bp for the farfield location of singapore on the sunda shelf in southeast asia the curve is based on more than 50 radiocarbon dates from elevations of 1 43 m to 15 09 m representing sea level index points in intertidal mangrove and shallow marine sediments deposited by sea level rise accompanying deglaciation the results indicate that mean sea level rose rapidly from around 17 m at 9500 cal bp to around 3 m by 8000 cal bp after this time the data suggest but do not unequivocally prove that the rate of sea rise slowed for a period of 300 500 years centred on 7700 cal bp shortly after the cessation of meltwater input to the oceans from the northern hemisphere renewed sea level rise amounting to 3 5 m began around 7400 cal bp and was complete by 7000 cal bp the existence of an inflection in the rate of sea level rise with a slow down centred on 7700 cal bp is broadly consistent with other available sea level curves over this interval and is supported by evidence of stable shorelines and delta initiation elsewhere at this time as well as evidence of comparatively rapid retreat of the west antarctic ice sheet beginning around 7500 cal bp stepped sea level rise occurring shortly after 7500 cal bp and also earlier during deglaciation may have served to focus significant post glacial episodes of human maritime coastal dispersal into comparatively narrow time intervals

thermal ionization mass spectrometry u series dating of a hominid site near nanjing china mass spectrometric u series dating of speleothems from tangshan cave combined with ecological and paleoclimatic evidence indicates that nanjing man a typical homo erectus morphologically correlated with peking man at zhoukoudian should be at least 580 k y old or more likely lived during the glacial oxygen isotope stage 16 similar to 620 ka such an age estimate which is similar to 270 ka older than previous electron spin resonance and alpha counting u series dates has significant implications for the evolution of asian h erectus dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages that of the enamel sample being only less than one fourth of the minimum age of nanjing man this suggests that u uptake history is far more complex than existing models can handle as a result great care must be taken in the interpretation of electron spin resonance and u series dates of fossil teeth

late quaternary structure and development of the northern ningaloo reef australia ningaloo reef situated on the central west coast is australia s largest fringing reef system extending southward from 22 s for over 200 km its narrow lagoon is backed by a coastal plain which is largely composed of an emergent last interglacial reef on the flank of folded tertiary limestones the west facing reef is exposed to strong oceanic swells across a narrow 8 km continental shelf climatic aridity cyclones tsunamis and the poleward flowing leeuwin current all influence the reef system seismic profiling and a coring and dating program along a transect through a reef pass indicate two periods of reef development in the northern part of the reef holocene and last interglacial seaward of the crest the holocene reef forms either a prominent 500 m wide bulge with 10 m of relief and an abrupt seaward slope or a series of discrete patch reefs holocene reef development is limited to depths of less than 30 m and reaches a maximum thickness of ca 10 15 m below the reef crest u th tims dates from distal parts of the last interglacial section between 18 and 36 m give ages toward the end of the high stand 120 115 ka last interglacial reef growth was more extensive of the two filling much of the available accommodation space perhaps as a result of a stronger leeuwin current this substrate subsequently provided an antecedent foundation for holocene reef development

a high precision record of mid late holocene sea level events from emergent coral pavements in the houtman abrolhos islands southwest australia early work on sea levels in southwest australia claimed to recognise a holocene sea level highstand which was not seen in better known sea level records elsewhere at the time more recent work has confirmed that a mid holocene highstand occurred about 6 kyr ago as new data on oscillating sea levels from the region have recently been published a high continuity precisely dated and accurately surveyed record was obtained from emergent coral pavements in the leeward houtman abrolhos islands serventy island a tectonically stable region from where good quality holocene sea level data have been previously obtained from corals from the mid holocene highstand ca 7 u th kyr ago sea level declined linearly during the remainder of the holocene as the carbonate platform prograded leewards hydro isostatic controls are probably significant in the record c 2005 elsevier ltd and inqua all rights reserved

late quaternary evolution of coral reefs on a cool water carbonate margin the abrolhos carbonate platforms southwest australia late quaternary coral reefs have developed on the southwestern australian margin which has otherwise been characterised by cool water carbonates since the eocene the houtman abrolhos coral reefs are at the limits of existence extending with the assistance of the leeuwin current a poleward flowing warm water stream into a region dominated by more temperate communities coring in the easter group reefs supported by high precision dating by both view the mathml source tims and 14 c methods has shown vigorous coral growth with reefs over 26 m thick in the holocene and over 15 m thick in the last interglacial each of the three abrolhos platforms consists of a central platform composed of last interglacial reefs about which windward and leeward holocene reefs developed asymmetrically reef peritidal and eolian facies comprise the emergent last interglacial limestones which are extensively calcretized with reef facies up to 5 m above msl the last interglacial high stand lasted for at least 10 ka from 130 to 120 ka and possibly 15 ka from 132 to 117 ka holocene reef facies are also emergent by 0 5 m and are overlain by peritidal and storm ridge facies in an upward shallowing sequence windward 10 m thick and leeward 26 m thick holocene reefs in the easter group show contrasting lithofacies the wave exposed windward reefs consist of a slow growing association of coralline algal bindstones and coral framestones whereas fast growing coral framestones dominate the more protected leeward reefs the leeward reefs commenced growth 10 000 years ago and grew to the present sea level by 6500 years ago generating holocene constructional topography consisting of blue hole terrain in the leeward parts of the platforms

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

freshwater forcing of abrupt climate change during the last glaciation large millennial scale fluctuations of the southern margin of the north american laurentide ice sheet occurred during the last deglaciation when the margin was located between about 43 and 49 n fluctuations of the ice margin triggered episodic increases in the flux of freshwater to the north atlantic by rerouting continental runoff from the mississippi river drainage to the hudson or st lawrence rivers we found that periods of increased freshwater flow to the north atlantic occurred at the same time as reductions in the formation of north atlantic deep water thus providing a mechanism for observed climate variability that may be generally characteristic of times of intermediate global ice volume