developing a framework of quaternary dune accumulation in the northern rub al khali arabia located at the crossroads between africa and eurasia arabia occupies a pivotal position for human migration and dispersal during the late pleistocene deducing the timing of humid and arid phases is critical to understanding when the rub al khali desert acted as a barrier to human movement and settlement recent geological mapping in the northern part of the rub al khali has enabled the quaternary history of the region to be put into a regional stratigraphical framework in addition to the active dunes two significant palaeodune sequences have been identified dating of key sections has enabled a chronology of dune accretion and stabilisation to be determined in addition previously published optically stimulated luminescence osl dates have been put in their proper stratigraphical context from which a record of late pleistocene dune activity can be constructed the results indicate the record of dune activity in the northern rub al khali is preservation limited and is synchronous with humid events driven by the incursion of the indian ocean monsoon

strontium in coral aragonite 3 sr coordination and geochemistry in relation to skeletal architecture abstract use of the coral sr palaeothermometer assumes that the sr in coral skeletons is substituted randomly for ca in the aragonite structure the presence of sr in additional phases e g strontianite or the non random distribution of sr across metal sites in aragonite would complicate the sr ca sea surface temperature relationship we have used sr k edge microexafs extended x ray absorption fine structure to determine the structural state of sr across selected microvolumes of four coral skeletons porites lobata acropora palmata pavona clavus and montastrea annularis we used a 5 3 m beam to analyse specific areas of the coral skeletal architecture i e centres of calcification fasciculi and dissepiments all exafs analyses refine within error to an ideally substituted sr in aragonite and we found no evidence of strontianite or partly ordered structural states anisotropy in the first shell responses results from the fact that the analysed microvolumes are not necessarily averaged for the responses of all crystal orientations in the aragonite although secondary ion mass spectrometry confirmed that sr ca composition can vary substantially between skeletal components we find no evidence for any contrast in sr structural state sr heterogeneity may result from kinetic effects reflecting complex disequilibrium processes during crystal precipitation or biological effects resulting from variations in the composition of the calcifying fluid which are biologically mediated

wind sedimentation in the jafurah sand sea saudi arabia the jafurah sand sea of the eastern province of saudi arabia extends along the arabian gulf coastline from kuwait in the north to the rub al khali in the south a distance of about 800 km sand drifts southward to south eastward from regions of high wind energy in the north to low wind energy in the south the aeolian landscape is zoned with areas of deflation transport and deposition from north to south drift rates in the zone of transport near abqaiq range from 2 m3 m w 1 yr 1 on sabkhas to 29 m3 m w 1 yr 1 on the crests of dunes average drift rates of approximately 18 m3 m w 1 yr 1 observed during the study can cause about 1 m of accumulation per 5500 yr in a 100 km zone of deposition downwind not including the bulk transport represented by the forward advance of dunes dune advance ranged from 23 m 2 9 m high dune to 3 m 23 m high dune during april october 1980 the study area consists of dune interdune sand sheet and siliciclastic sabkha terrains each of which is characterized by differing drift rates and differing rates of erosion or deposition sedimentation occurs by lateral movement of dunes and interdunes and vertical accretion by sand sheets and sabkhas

a study of cleaning procedures used for foraminiferal mg ca paleothermometry the various cleaning steps required for preparation of foraminiferal samples for mg ca and sr ca analysis are evaluated for their relative importance and effects on measured elemental ratios it is shown that the removal of silicate contamination is the most important step for the measurement of mg ca ratios in an example bulk sample mg ca decreases from 10 5 to 2 5 mmol mol 1 during clay removal oxidation of organic material causes a lowering of sample mg ca in the order of 10 or approximately 1 c when converted to temperature use of dilute acid leaching to remove adsorbed contaminants causes partial dissolution of the sample carbonate and a corresponding decrease in mg ca reductive treatment also causes dissolution of the sample and a decrease in the mg ca ratio of up to 10 15 sample preparation for sr ca analysis does not require the same degree of rigor as is necessary for mg ca work the within run reproducibility of the method described here for g ruber in a core top sample from the arabian sea was 1 8 mean sample ratio was 4 72 mmol mol 1 when converted to temperature this becomes 28 0 2 c the equivalent result for sr ca was 0 5 mean ratio 1 44 mmol mol 1

tropical sea surface temperatures for the past four centuries reconstructed from coral archives most annually resolved climate reconstructions of the common era are based on terrestrial data making it a challenge to independently assess how recent climate changes have affected the oceans here as part of the past global changes ocean2k project we present four regionally calibrated and validated reconstructions of sea surface temperatures in the tropics based on 57 published and publicly archived marine paleoclimate data sets derived exclusively from tropical coral archives validation exercises suggest that our reconstructions are interpretable for much of the past 400 years depending on the availability of paleoclimate data within and the reconstruction validation statistics for each target region analysis of the trends in the data suggests that the indian western pacific and western atlantic ocean regions were cooling until modern warming began around the 1830s the early 1800s were an exceptionally cool period in the indo pacific region likely due to multiple large tropical volcanic eruptions occurring in the early nineteenth century decadal scale variability is a quasi persistent feature of all basins twentieth century warming associated with greenhouse gas emissions is apparent in the indian west pacific and western atlantic oceans but we find no evidence that either natural or anthropogenic forcings have altered el nino southern oscillation related variance in tropical sea surface temperatures our marine based regional paleoclimate reconstructions serve as benchmarks against which terrestrial reconstructions as well as climate model simulations can be compared and as a basis for studying the processes by which the tropical oceans mediate climate variability and change

holocene shorelines and tectonic movements in eastern saudi arabia abstract although quaternary marine terraces have been reported from eastern saudi arabia at heights of up to 150 m unambiguous shoreline deposits could be identified only within 3 m of present day high water and close to the modern shoreline unaltered aragonitic mollusc shells from five such deposits yielded 14 c ages of 3700 6000 yr b p comparison of their elevations with those of coeval deposits on the zagros coast of iran demonstrates the relative stability of the saudi shore of the gulf during the late holocene

relative sea level fall since the last interglacial stage are coasts uplifting worldwide the growing interest in quantification of vertical ground motion stems from the need to understand in detail how the earth s crust behaves for both scientific and social reasons however only recently has the refinement of dating techniques made possible the use of paleoshorelines as reliable tools for tectonic studies although there are many local studies of quaternary vertical motions of coastlines we know of no comprehensive worldwide synthesis here we provide a compilation of 890 records of paleoshoreline sequences with particular emphasis on the last interglacial stage marine isotopic stage mis 5e 122 ka the quality of dating mis 5e makes it a reliable marker to evaluate vertical ground motion rates during the late quaternary on a global scale the results show that most coastal segments have risen relative to sea level with a mean uplift rate higher than 0 2 mm yr i e more than four times faster than the estimated eustatic drop in sea level the results also reveal that the uplift rate is faster on average for active margins than for passive margins neither dynamic topography nor glacio hydro isostasy may explain sustained uplift of all continental margins as revealed by the wide distribution of uplifted sequences of paleoshorelines instead we suggest that only plate tectonic processes reconcile all observations of quaternary coastal uplift we propose that long term continental accretion has led to compression of continental plates and uplift of their margins therefore this study concludes that plate tectonics processes impact all margins and emphasizes the fact that the notion of a stable platform is unrealistic these results therefore seriously challenge the evaluation of past sea levels from the fossil shoreline record

geomorphological and palaeoenvironmental investigations in the southeastern arabian gulf region and the implication for the archaeology of the region abstract during the late quaternary the climate of arabia has fluctuated between periods of higher rainfall and fluvial activity dominated by the influence of the indian ocean monsoon iom and drier arid conditions under the influence of the westerlies this has left a rich legacy of landforms from which temporal and spatial patterns of environmental change are reconstructed the coastal desert region of the southeastern arabian gulf has been a focal point for human settlement since 8000 cal yr bp the region is strategically located on an important trade route between two cradles of civilization namely mesopotamia and the indus changes in the evolution and modification of this landscape under varying climatic conditions have influenced humans living in and exploiting this landscape for food and water raw materials and trade routes in this study geomorphological and palaeoenvironmental investigations are integrated to provide a framework of environmental change for the late glacial and early mid holocene periods against which the archaeology of the area can be set the late glacial and earliest holocene was characterised by intense aridity and accumulation of mega linear dunes driven by the shamal winds in the arabian gulf region this continued into the earliest part of the holocene whilst southern arabia was under the influence of the iom the monsoon rains migrated into the gulf region between 8500 6000 cal bp during this time semi nomadic herders occupied this region and grazing their animals in a landscape covered with c3 savanna grassland the neolithic peoples also practised hunting and fishing and the collection of shellfish was an important activity pottery shows links with mesopotamia at this time from 6000 cal bp the iom retreated south and rainfall was derived from winterly westerly sources under drier conditions a switch occurred to a sparser cover of c4 grasses from 4500 cal bp the climate became much drier with the development of stronger westerly summer shamal winds and the reactivation of dunes across the region an intense arid period occurred at 4100 bp which corresponds with major drought conditions in mesopotamia and the indus region which led to major changes in society this event occurs at a major transition in the arabian gulf bronze age archaeological record with a decline in population and trade the last 4000 yr has largely been characterised by arid conditions similar to those found in the region today

eustatic control of late quaternary sea level change in the arabian persian gulf accurate sea level reconstruction is critical in understanding the drivers of coastal evolution inliers of shallow marine limestone and aeolianite are exposed as zeugen carbonate capped erosional remnants on the southern coast of the arabian persian gulf these have generally been accepted as evidence of a eustatically driven last interglacial relative sea level highstand preceded by a penultimate glacial age lowstand instead recent optically stimulated luminescence osl dating suggests a last glacial age for these deposits requiring 100 m of uplift since the last glacial maximum in order to keep pace with eustatic sea level rise and implying the need for a wholesale revision of tectonic stratigraphic and sea level histories of the gulf these two hypotheses have radically different implications for regional neotectonics and land sea distribution histories here we test these hypotheses using osl dating of the zeugen formations these new ages are remarkably consistent with earlier interpretations of the formations being last interglacial or older in age showing that tectonic movements are negligible and eustatic sea level variations are responsible for local sea level changes in the gulf the cause of the large age differences between recent studies is unclear although it appears related to large differences in the measured accumulated dose in different osl samples

palaeoenvironmental and sea level changes during the holocene in eastern saudi arabia and their implications for neolithic populations abstract this paper presents the key findings of a multidisciplinary study investigating the nature and timing of coastal landscape evolution in eastern saudi arabia during the holocene to date most sea level reconstructions for the arabo persian gulf are based on uncalibrated 14c ages without correction for marine reservoir effects or lack precision with regard to the effects of neotectonic changes indicators of sea level used errors in elevation of sedimentary units used and the relationship with actual tides as a consequence the nature and timing of relative sea level rsl changes during the late pleistocene and holocene remain poorly understood to help address this we use sea level index points slips based on calibrated 14c ages to present a rsl curve for the central southern gulf of saudi arabia from coastal sabkha deposits near the archaeological site of dosariyah the sediments record rapid transgression during the early holocene with a mid holocene high stand immediately prior to 6880 6560 cal bp when the upper limit for the palaeo mean highest high tide water mhhw was 2 8 3 10 m above present day mean sea level transgression continued until shortly after 5575 5310 cal bp with an upper limit to the palaeo mhhw of 3 75 m above present sea levels thereafter a fall in rsl was recorded with the regression leading to the progradation of the coastal system and the development of coastal sabkhas nonetheless later transgressions are recorded in the region between 4848 4536 and 4335 3949 cal bp radiometric dating results from archaeological excavations at dosariyah one of the most important neolithic coastal sites in the gulf suggest that occupation of the site during the neolithic coincides with the mid holocene marine transgression ca 7200 6500 cal bp whilst the close proximity of the site to the sea may have facilitated maritime exchange activities occupation of the site was short lived and the phase of abandonment occurred during a period of rapid rsl rise which would have transformed the area around dosariyah into an island or certainly cut it off tidally from the mainland

gas venting and late quaternary sedimentation in the persian arabian gulf abstract high resolution 3 5 khz echo sounding profiles and piston cores were used to reconstruct the microtopography and late quaternary depositional history of the persian gulf perversive throughout the seafloor of the gulf is an extensive network of pockmarks formed by seepages of thermogenic gas these gas seeps and bottom water exiting the gulf via the strait of hormuz are the most significant processes controlling present day sedimentation in the region erosion by these seeps has been so intense in the baiban shelf in the strait of hormuz as to create a hoodoo like terrain on the outer shelf the surfical geology of the gulf documents a short lived transgression 29 400 to 22 800 years ago during the wisconsin regression which began 125 000 years ago the wisconsin regressive maxima when sea level dropped to 120 130 m about 21 000 20 000 years ago and the climate was dry and eolian and paralic sedimentation characterized the gulf the holocene transgression 18 000 to 12 000 years ago when the climate was more humid than during the climax of the wisconsin regression a dry phase 12 000 to 9000 years ago when the persian gulf was a site of eolian and carbonate deposition and the present sediment cycle during the last 9000 years under a more humid regime it was during the present cycle that southeast trending marl lobes were deposited off iran arabia acquired its hyper arid climate about 3000 years ago and the gulf attained its present configuration about 1000 years ago as a result of the construction of the tigris euphrates delta at its head and tectonism and aggradation along its arabian and iranian flanks

prograded foredunes of western australia s macro tidal coast implications for holocene sea level change and high energy wave impacts the holocene evolution of the canning coast of western australia has largely been overlooked so far mainly due to its remoteness and low population density we report on new data from a sequence of foredunes inside the macro tidal admiral bay 110 km southwest of broome based on sediment cores differential global positioning system dgps based elevation transects and stratigraphical analyses on outcrops of the relict foredunes we aim at reconstructing holocene coastal changes and relative sea levels rsls as well as identifying and dating imprints of extreme wave events sedimentary analyses comprise the documentation of bedding structures foraminiferal content and macrofaunal remains grain size distribution and organic matter the chronological framework is based on 26 carbon 14 accelerator mass spectrometry 14c ams datings marine flooding of the pre holocene surface landward of the 2 5 km wide foredune barriers occurred 7400 7200 cal bp when mangroves colonized the area after only 200 400 years a high energy inter tidal environment established and prevailed until c 4000 cal bp before turning into the present supralittoral mudflat during that time coastal regression led to beach progradation and the formation of aligned foredunes drivers of progradation were a stable rsl or gradual rsl fall after the mid holocene and a positive sand budget the foredunes overlie upper beach deposits located up to 2 m above the present upper beach level and provide evidence for a higher mid holocene rsl discontinuous layers of coarse shells and sand are intercalated in the foredunes indicating massive coastal flooding events one such layer was traced over three dune ridges and dated to c 1700 1550 cal bp however it seems that most tropical cyclones induce net erosion rather than deposition at aligned foredunes and thus they are only suitable for reconstructing temporal variability if erosional features or sedimentation reliably tied to these events can be identified and dated accurately copyright 2014 john wiley sons ltd

a multi proxy analysis of the holocene humid phase from the united arab emirates and its implications for southeast arabia s neolithic populations an early to mid holocene humid phase has been identified in various arabian geo archives although significant regional heterogeneity has been reported in the onset duration and stability of this period a multi proxy lake and dune record from wahalah in the united arab emirates uae documents significant variations in hydrology biological productivity and landscape stability during the first half of the holocene these data reveal that post last glacial maximum dune emplacement continued into the earliest part of the holocene with the onset of permanent lacustrine sedimentation at the site commencing 8 5 ka cal bp a long term shift towards more arid conditions is inferred between 7 8 and 5 9 ka cal bp with intermittent flooding of the basin and distinct phases of instability throughout the catchment area this transition is linked to the southwards migration of the intertropical convergence zone itcz and associated weakening of monsoon rains a peak in landscape instability is recorded between 5 9 and 5 3 ka cal bp and is marked by a pronounced increase in regional dune emplacement these variations are considered alongside the record of human settlement raising important questions about the interactions between population demographics climate and environment in southeast arabia during the neolithic

ams dated mollusks in beach ridges and berms document holocene sea level and coastal changes in northeastern kuwait bay abstract in northeastern kuwait ancient beach ridges and associated berms are separated from the present shoreline by a 4 6 km wide sabkha a diverse mollusk fauna in the beach ridges attests to a former open marine environment a total of 21 ams dates were obtained in this study thirteen mollusk samples from beach ridges yielded ams dates ranging from 6990 cal yr bp in the southeast to 3370 cal yr bp in the northwest suggesting a southeast to northwest age progression during the holocene transgression in contrast four samples from berms throughout the study area yielded ams dates of 5195 3350 cal yr bp showing no age progression these berms consist largely of conomurex persicus gastropods that aggregated by storms during a highstand at 5000 3500 cal yr bp the berms are presently at 6 m above sea level 2 3 m above the beach ridges human settlements were common on the ridge crests before and after the highstand regression to present day sea level commenced after the highstand which is when the sabkha began forming a landward marine built terrace which yielded ams dates 43 500 14 c yr bp probably formed during marine oxygen isotope stage 5e and hence is not genetically related to the beach ridges

global warming in an independent record of the past 130 years 1 the thermometer based global surface temperature time series gst commands a prominent role in the evidence for global warming yet this record has considerable uncertainty an independent record with better geographic coverage would be valuable in understanding recent change in the context of natural variability we compiled the paleo index pi from 173 temperature sensitive proxy time series corals ice cores speleothems lake and ocean sediments historical documents each series was normalized to produce index values of change relative to a 1901 2000 base period the index values were then averaged from 1880 to 1995 the index trends significantly upward similar to the gst smaller scale aspects of the gst including two warming trends and a warm interval during the 1940s are also observed in the pi the pi extends to 1730 with 67 records the upward trend appears to begin in the early 19th century but the year to year variability is large and the 1730 1929 trend is small

quantification of carbonate ramp sedimentation and progradation rates for the late holocene abu dhabi shoreline abstract we utilize new radiocarbon dates and detailed sedimentological logging of the abu dhabi sabkha to produce the first well constrained internally consistent rates for late holocene carbonate ramp sediment accumulation and progradation for the southern shore of the persian gulf these data are applied to test the hypothesis that in low angle carbonate ramp systems ramp geometry is the primary control on sedimentation and progradation rates and therefore estimates acquired from other depositional environments cannot be applied to low angle carbonate ramp systems average calculated progradation rates of 0 75 m yr are higher than progradation rates proposed for other late holocene and recent carbonate settings a relationship that is explained by the lack of accommodation space in the low angle laterally extensive ramp system in the sedimentary record such relatively high progradation rates would produce laterally extensive lithologically uniform units with little or no evidence of progradational features and would appear to be largely contemporaneous across their extent the total average sediment accumulation rate of 0 029 cm yr is lower than those proposed from most other late holocene to recent shallow water carbonate depositional environments again a relationship interpreted to result from the limited accommodation space of low angle carbonate ramp systems calculated sediment accumulation rates show little variation over the past 1 400 years yet the calculated progradation rates exhibit a sharp decline from a maximum of 1 03 m yr before 677 946 cal bp to 0 70 m yr afterwards this is interpreted to reflect a rise in relative sea level or distal steepening of the ramp system applying the progradation rates proposed in this paper the lagoon system in the study area would be completely infilled in less than 4 000 years calculated sediment accumulation rates for syndepositional and early postdepositional interstitial displacive evaporite formation are higher than those for carbonate and microbial mat intervals continued precipitation of evaporite minerals during burial would result in a further increase in their relative contribution to the sediment pile conversely compaction particularly of microbial mat intervals will result in a decrease in apparent sediment accumulation rates for non evaporite intervals these processes need to be considered when modeling the basin evolution of mixed evaporite carbonate sequences in the stratigraphic record during calculation of sedimentation rates it is important to consider both a correction for compaction and a correction for evaporite formation

a core top assessment of proxies for the ocean carbonate system in surface dwelling foraminifers we have assessed the reliability of several foraminifer hosted proxies of the ocean carbonate system 11b b ca and u ca using holocene samples from the atlantic and pacific oceans we examined chemical variability over a range of test sizes for two surface dwelling foraminifers globigerinoides sacculifer and globigerinoides ruber measurements of 11b in g ruber show no significant relationship with test size in either atlantic or pacific sites and appear to provide a robust proxy of surface seawater ph likewise there is no significant variability in the 11b of our atlantic core top g sacculifer but we find that 11b increases with increasing test size for g sacculifer in the pacific these systematic differences in 11b are inferred to be a consequence of isotopically light gametogenic calcite in g sacculifer and its preferential preservation during postdepositional dissolution the trace element ratio proxies of ocean carbonate equilibria u ca and b ca show systematic increases in both g ruber and g sacculifer with increasing test size possibly as a result of changing growth rates this behavior complicates their use in paleoceanographic reconstructions in keeping with several previous studies we find that mg ca ratios increase with increasing size fraction in our well preserved atlantic g sacculifer but not in g ruber in contrast to previous interpretations we suggest that these observations reflect a proportionally larger influence of compositionally distinct gametogenic calcite in small individuals compared to larger ones as with 11b this influences g sacculifer but not g ruber which has negligible gametogenic calcite

global to local scale parameters determining relative sea level changes and the post glacial isostatic adjustment of great britain abstract observations of relative sea level rsl change in great britain since 16 kyr bp and models of post glacial isostatic adjustment provide constraints on reconstructions of the british and antarctic ice sheets from the last glacial maximum to the present we use the global model from an earlier investigation modified ice 4g vm2 with lithospheric thickness 90 km which gives good rsl fits globally as well as for much of the british data a revised ice model for great britain that fits with recently published observations on ice limits and heights fails to explain all the misfits between rsl observations and predictions much more significant improvements result from models that incorporate a different chronology for the partial deglaciation of antarctica while keeping the total ice melt 17 m the same as in ice 4g vm2 the results suggest antarctic melting of 3 m ice equivalent sea level by 15 kyr bp only 1 m contribution to the 24 m rise of mwp1a with the major melting 12 5 kyr bp and a small amount of melting 1 0 0 3 m between then and 3 or 2 kyr bp these modifications produce rsl predictions for barbados that show the major changes in rate of sea level rise but with an offset up to 1 kyr compared to the observations possible explanations that remain to be investigated further are a delay in the melting of ice from some other region a reduction in the total melt derived from antarctica and a refinement of the 1 kyr temporal resolution assumed in the construction of the theoretical solution

sea surface temperature and salinity reconstruction from coral geochemical tracers massive scleractinian corals secrete an aragonitic skeleton which incorporates a large array of chemical tracers corals present several advantages for palaeoclimate research they grow continuously and can live up to 1000 years they are easy to date and they can be sampled at high resolution weekly to monthly resolution both live and fossil corals can be collected in the field in the past two decades significant efforts have been made to identify robust tracers of sea surface temperature sst and salinity sss in corals to date sr ca and 18o are considered to be the most reliable sst tracers although changes in seawater 18o can significantly alter sst reconstructed from coralline 18o because these variations in seawater 18o can be linked to sss changes this initial problem can in fact be turned into an advantage and provide us with an sss tracer the sst component in the coral 18o signal can either be evaluated through sr ca measurements or in some case simply filtered out however there is still much uncertainty concerning the exact mode of incorporation of trace elements and stable isotopes into the coral skeleton the effects of growth rate light intensity feeding habits ph and water chemistry are still poorly documented a review of the strength and weaknesses of sr ca and 18o is presented together with some examples of sst and sss reconstructions other potential sst tracers are also reviewed it is expected that the ability to grow corals in aquarium under controlled conditions and that the development of sophisticated analytical techniques at the micrometric level should help us understand better the robustness of each tracers and the factors controlling their incorporation in coral aragonite

late quaternary sea level changes of the persian gulf abstract late quaternary reflooding of the persian gulf climaxed with the mid holocene highstand previously variously dated between 6 and 3 4 ka examination of the stratigraphic and paleoenvironmental context of a mid holocene whale beaching allows us to accurately constrain the timing of the transgressive highstand and regressive phases of the mid to late holocene sea level highstand in the persian gulf mid holocene transgression of the gulf surpassed today s sea level by 7100 6890 cal yr bp attaining a highstand of 1 m above current sea level shortly after 5290 4570 cal yr bp before falling back to current levels by 1440 1170 cal yr bp the cetacean beached into an intertidal hardground pond during the transgressive phase 5300 4960 cal yr bp with continued transgression interring the skeleton in shallow subtidal sediments subsequent relative sea level fall produced a forced regression with consequent progradation of the coastal system these new ages refine previously reported timings for the mid to late holocene sea level highstand published for other regions by so doing they allow us to constrain the timing of this correlatable global eustatic event more accurately

a high resolution calibration of sr ca thermometry using the caribbean coral montastraea annularis 1 a relationship has been established between the sr ca ratio in the skeleton of the scleractinian coral montastraea annularis and sea surface water temperature in south florida in order to obtain this correlation specimens of montastraea annularis were transplanted to a site at a local reef where every two to three months throughout a 2 year period the corals were stained with alizarin red s and where water temperature which annually ranges between 20 and 30 c was continually monitored at the end of the experimental period the coral skeleton was sampled at a rate of 50 samples per year each sample corresponding to only around 20 g of calcium carbonate for the 2 5 year period the sr ca ratio exhibited excellent correlation in the first year r2 0 83 sr ca mmol mol 10 11 0 0452 sst c but a rather poorer correlation in the second year r2 0 68 sr ca mmol mol 10 09 0 0406 sst c averaging the data into monthly values for year 1 we determined a relationship of sr ca mmol mol 10 165 0 0471 sst c on the basis of the excellent correlation between temperature and sr ca we feel that this relationship is the most accurate discrepancies in the second year are suggested to arise from slight sampling errors relative to the stain lines

calibration of mg ca thermometry in planktonic foraminifera from a sediment trap time series 1 paired mg ca and 18o measurements on planktonic foraminiferal species g ruber white g ruber pink g sacculifer g conglobatus g aequilateralis o universa n dutertrei p obliquiloculata g inflata g truncatulinoides g hirsuta and g crassaformis from a 6 year sediment trap time series in the sargasso sea were used to define the sensitivity of foraminiferal mg ca to calcification temperature habitat depths and calcification temperatures were estimated from comparison of 18o of foraminifera with equilibrium calcite based on historical temperature and salinity data when considered together mg ca mmol mol of all species except two show a significant r 0 93 relationship with temperature t c of the form mg ca 0 38 0 02 exp 0 090 0 003 t equivalent to a 9 0 0 3 change in mg ca for a 1 c change in temperature small differences exist in calibrations between species and between different size fractions of the same species o universa and g aequilateralis have higher mg ca than other species and in general data can be best described with the same temperature sensitivity for all species and pre exponential constants in the sequence o universa g aequilateralis g bulloides g ruber g sacculifer other species this approach gives an accuracy of 1 2 c in the estimation of calcification temperature the 9 sensitivity to temperature is similar to published studies from culture and core top calibrations but differences exist from some literature values of pre exponential constants different cleaning methodologies and artefacts of core top dissolution are probably implicated and perhaps environmental factors yet understood planktonic foraminiferal mg ca temperature estimates can be used for reconstructing surface temperatures and mixed and thermocline temperatures using g ruber pink g ruber white g sacculifer n dutertrei p obliquiloculata etc the existence of a single mg thermometry equation is valuable for extinct species although use of species specific equations will where statistically significant provide more accurate evaluation of mg ca paleotemperature

interpreting sea surface temperature from strontium calcium ratios in montastrea corals link with growth rate and implications for proxy reconstructions 1 we analyzed strontium calcium ratios sr ca in four colonies of the atlantic coral genus montastrea with growth rates ranging from 2 3 to 12 6 mm a 1 derived sr ca sea surface temperature sst calibrations exhibit significant differences among the four colonies that cannot be explained by variations in sst or seawater sr ca for a single coral sr ca ratio of 8 8 mmol mol 1 the four calibrations predict ssts ranging from 24 0 to 30 9 c we find that differences in the sr ca sst relationships are correlated systematically with the average annual extension rate ext of each colony such that sr ca mmol mol 1 11 82 0 13 0 058 0 004 ext mm a 1 0 092 0 005 sst c this observation is consistent with previous reports of a link between coral sr ca and growth rate verification of our growth dependent sr ca sst calibration using a coral excluded from the calibration reconstructs the mean and seasonal amplitude of the actual recorded sst to within 0 3 c applying a traditional nongrowth dependent sr ca sst calibration derived from a modern montastrea to the sr ca ratios of a conspecific coral that grew during the early little ice age lia 400 years b p suggests that caribbean ssts were 5 c cooler than today conversely application of our growth dependent sr ca sst calibration to sr ca ratios derived from the lia coral indicates that ssts during the 5 year period analyzed were within error 1 4 c of modern values

extracting a climate signal from the skeletal geochemistry of the caribbean coral siderastrea siderea 1 the first bimonthly time series of paired 18o and sr ca from the slow growing coral siderastrea siderea from the dry tortugas florida has been generated that documents that robust proxy climate records of the tropical atlantic and intraamerican seas can be produced from this massive coral the time series contain a 20 year long calibration window 1973 1992 for both 18o and sr ca and a 73 year long verification window 1900 1972 for sr ca these time series permit the quantification of the relationship between coral 18o sst and sr ca sst and the assessment of the stability of the proxy relationships over time both coral geochemical records are highly correlated with the augmented instrumental sst record through the calibration period and sr ca remains highly correlated through the verification period both at the bimonthly r 0 97 and annual average resolution r 0 72 coral 18o and sr ca are highly reproducible within the same core and sr ca exhibits no extension related vital effects this study sets the stage for generating multicentury scale climate records from the tropical atlantic ocean using the skeletal geochemistry of this massive but slow growing coral

an apparent vital effect of calcification rate on the sr ca temperature proxy in the reef coral montipora capitata 1 measuring the strontium to calcium ratio in coral skeletons reveals information on seawater temperatures during skeletal deposition but studies have shown additional variables may affect the ratio here we measured sr ca in the reef coral montipora capitata grown in six mesocosms continuously supplied with seawater from the adjacent reef flat three mesocosms were ambient controls and three had seawater chemistry simulating ocean acidification oa we found that sr ca was not affected by the oa treatment and neither was coral calcification for these small colonies larger colonies did show an oa effect the lack of oa effects allowed us to test the hypothesis that coral growth rate can affect sr ca using the natural range in calcification rates of the corals grown at the same temperature we found that sr ca was inversely related to calcification rate sr ca 9 385 0 0040 calcification rate using a previously published calibration curve for this species a 22 mg d 1 colony 1increase in calcification rate introduced a 1 c warmer temperature estimate with the 27 corals reporting temperatures ranging from 24 9 to 28 9 c with mean 26 6 0 9 c standard deviation our results lend support to hypotheses invoking kinetic processes and growth rate to explain vital effects on sr ca however uncertainty in the slope of the regression of sr ca on calcification and a low r squared value lead us to conclude that sr ca could still be a useful proxy in this species given sufficient replication or by including growth rate in the calibration

intrareef variations in li mg and sr ca sea surface temperature proxies in the caribbean reef building coral siderastrea siderea caribbean sea surface temperatures ssts have increased at a rate of 0 2 c per decade since 1971 a rate double that of the mean global change recent investigations of the coral siderastrea siderea on the belize mesoamerican barrier reef system mbrs have demonstrated that warming over the last 30 years has had a detrimental impact on calcification instrumental temperature records in this region are sparse making it necessary to reconstruct longer sst records indirectly through geochemical temperature proxies here we investigate the skeletal sr ca and li mg ratios of s siderea from two distinct reef zones forereef and backreef of the mbrs our field calibrations of s siderea show that li mg and sr ca ratios are well correlated with temperature although both ratios are 3 times more sensitive to temperature change in the forereef than in the backreef these differences suggest that a secondary parameter also influences these sst proxies highlighting the importance for site and species specific sst calibrations application of these paleothermometers to downcore samples reveals highly uncertain reconstructed temperatures in backreef coral but well matched reconstructed temperatures in forereef coral both between sr ca ssts and li mg ssts and in comparison to the hadley centre sea ice and sea surface temperature record reconstructions generated from a combined sr ca and li mg multiproxy calibration improve the precision of these sst reconstructions this result confirms that there are circumstances in which both li mg and sr ca are reliable as stand alone and combined proxies of sea surface temperature however the results also highlight that high precision site specific calibrations remain critical for reconstructing accurate ssts from coral based elemental proxies

low latitude holocene hydroclimate derived from lake sediment flux and geochemistry this study investigates hydrological responses to climatic shifts using sediment flux data derived from two dated palaeolake records in south east arabia flux values are generally low during the early holocene humid period ehhp 9 0 6 4k cal a bp although several short lived pulses of increased detrital input are recorded the most prominent of which is dated between 8 3 and 7 9k cal a bp the ehhp is separated from the mid holocene humid period mhhp 5 0 4 3k cal a bp by a phase of increased sediment flux and aridity which began between 6 4 and 5 9k cal a bp and peaked between 5 2 and 5 0k cal a bp the termination of the mhhp is marked by a phase of high detrital sediment flux between 4 3 and 3 9k cal a bp while long term shifts in climate are most likely linked to changes in the summer position of the intertropical convergence zone and associated indian and african monsoon systems it is noted that the abrupt short term phases of aridity observed in both records are coeval with intervals of rapid climate change globally which triggered non linear widespread landscape reconfigurations throughout south east arabia

holocene shoreline variations in the persian gulf example of the umm al qowayn lagoon uae abstract the united arab emirate lagoons display several generations of successively settled coastal spits the study of which allows reconstruction of the holocene shoreline changes from the end of the last marine transgression the very variable volume of sediment migrating along the coast attests climatic changes on the other hand vertical shoreline variations are documented by high sea level evidence around 6000 4500 3500 and 2500 bp when compared with other areas on the persian gulf southern coast kuwait and bahrain such holocene oscillations might be interpreted as tectonic in origin

a high resolution sr ca and δ18o coral record from the great barrier reef australia and the 1982 1983 el nino abstract a high resolution near weekly sr ca and oxygen isotopic record is presented for a coral from the pandora reef in the great barrier reef gbr of australia during the period 1978 to 1984 the records are well correlated except for periods of high rainfall when river runoff has significantly modified the 18o value of seawater using the sr ca temperature calibration of de villiers et al 1994 the sr ca records exhibit seasonally controlled cyclical sst sea surface temperature variations of from 21 to 28 c during the very strong el nino of 1982 1983 the sr ca systematics indicate a sharp drop in the winter sst to 18 5 c this represents a temperature anomaly of 3 c which is approximately twice that given by the 18o variations suggesting an 2 amplification of the anomaly by the sr ca system possibly due to the increasing dominance of inorganically controlled aragoniteseawater fractionation the oxygen isotopic systematics show the combined effects of both temperature and changing seawater 18o values the latter reflecting the influx of 18o depleted runoff during periods of high rainfall due to the extremely low 10 3 sr and ca contents of river run off relative to seawater it is possible to use the sr ca thermometer to calculate temperatures independent of major floods and hence deconvolve the combined effects in the oxygen isotopic record of variable temperature and the 18o value of seawater using this approach it is possible to quantitatively reproduce the volume of runoff from the burdekin river during the periods of major flooding that occurred in early 1979 and 1981 the results of this study demonstrate that the combined use of high resolution sr ca and 18o systematics in scleractinian corals is a powerful tool for providing quantitative constraints on past climate

optically stimulated luminescence dating of the city wall system of ancient tayma nw saudi arabia abstract in addition to a series of chronological markers artefacts pottery in the archaeological contexts of ancient tayma nw saudi arabia optically stimulated luminescence osl and radiocarbon dating techniques were applied to generate reliable ages for the city wall system of the oasis a massive aeolian sand deposit burying the oldest part of the outer wall of tayma was sampled to obtain a minimum age for the construction of this wall the sequence of osl ages from the inactive dune id 4900 300 a 5100 400 a 4400 300 a 3900 200 a 4000 200 a is in full accordance with 14 c ams ages of charcoal embedded into the same dune 4190 4420 cal bp 3870 4080 cal bp underlying alluvial samples from the inactive gravel sheet igs in contrast give maximum ages for the construction which scatter between 6600 300 a and 4900 400 a the new dating sequence provides evidence that the oldest part of the ancient city wall system already existed in the 2nd half of the 3rd mill bc which is earlier than expected thus far from archaeological and architectural interpretation

high magnesium primary magmas from haleakala volcano east maui hawaii petrography nickel and major element constraints abstract for any given volcanic field the compositions of primary melts provide important constraints on models of magmatic processes and volcanic eruptions in this paper based on petrography olivine and bulk rock compositions two tholeiitic picrites samples c122 and c123 from haleakala volcano east maui are evaluated as possible primary melts sample c122 bulk rock mgo 16 6 has a high apparent mg fe exchange coefficient kd between olivine phenocrysts and bulk rock 0 6 however major elements and ni mass balance calculations show that the olivines in c122 are in equilibrium with the residual melt matrix after closed system equilibrium fractionation of 25 wt olivine therefore the mg fe ratio ca content and ni content of c122 are consistent with the hypothesis that the bulk composition of c122 is close to a primary melt formed by partial melting of a mantle containing olivine with composition around fo89 to fo91 the uniform composition and small size mostly 0 2 0 3 mm of the olivine and the glass patches in the matrix suggest fast ascent and rapid cooling at shallow depth for c122 on the contrary sample c123 which has an apparent kd between the most mafic olivine megacrysts and the bulk rock close to the equilibrium value 0 27 the multiple planar subgrain boundaries in most of the olivine crystals indicate that it may not be a primary melt unless the deformed olivines are generated at magmatic condition as phenocrysts if the deformed subgrain boundary texture in olivine could indeed be generated at magmatic condition then the wide compositional range of olivine crystals in c123 fo74 to fo91 suggests multi stage crystallization over a wide range of cooling temperatures the compositions of the two picrites and a differentiated basalt which does not contain xenocrysts suggest that the haleakala tholeiites are derived from primary melts with at least 16 17 wt mgo lavas with such high mgo content are rare in haleakala and other hawaiian volcanoes therefore most hawaiian tholeiites must have undergone extensive fractionation histories

shoreline reconstructions for the persian gulf since the last glacial maximum abstract sea level change in the persian gulf since the time of the last maximum glaciation at about 18 000 yr bp is predicted to exhibit considerable spatial variability because of the response of the earth to glacial unloading of the distant ice sheets and to the meltwater loading of the gulf itself and the adjacent ocean models for these glacio hydro isostatic effects have been compared with observations of sea level change and palaeoshoreline reconstructions of the gulf have been made from the peak of the glaciation until about 14 000 yr bp the gulf is free of marine influence out to the edge of the biaban shelf by 14 000 yr bp the strait of hormuz had opened up as a narrow waterway and by about 12 500 years ago the marine incursion into the central basin had started the western basin flooded about 1000 years later momentary stillstands may have occurred during the gulf flooding phase at about 11 300 and 10 500 yr bp the present shorelines was reached shortly before 6000 yr ago and exceeded as relative sea level rose 1 2 m above its present level inundating the low lying areas of lower mesopotamia these reconstructions have implications for models of the evolution of the euphrates tigris karun delta as well as for the movements of people and the timing of the earliest settlements in lower mesopotamia for example the early gulf floor would have provided a natural route for people moving westwards from regions to the east of iran from the late palaeolithic to early neolithic

compositional variability in a cold water scleractinian lophelia pertusa new insights into vital effects we analyzed sr ca and mg ca ratios in the thecal wall of lophelia pertusa a cold water coral using sims ion microprobe techniques the wall grows by simultaneous upward extension and outward thickening compositional variability displays similar trends along the upward and outward growth axes sr ca and mg ca ratios oscillate systematically and inversely the sensitivity of lophelia sr ca ratios to the annual temperature cycle 0 18 mmol mol 1 c is twice as strong as that exhibited by tropical reef corals and four times as strong as the temperature dependence of sr ca ratios of abiogenic aragonites precipitated experimentally from seawater a comparison of the skeletal composition of lophelia with results from precipitation calculations carried out using experimentally determined partition coefficients suggests that both temperature dependent element partitioning and seasonal changes in the mass fraction of aragonite precipitated from the calcifying fluid influence the composition of lophelia skeleton results from calculations that combine these effects reproduce both the exaggerated amplitude of the sr ca and mg ca oscillations and the inverse relationship between sr ca and mg ca ratios

the effect of skeletal mass accumulation in porites on coral sr ca and δ18o paleothermometry 1 paleotemperature estimates based on coral sr ca have not been widely accepted because the reconstructed glacial holocene shift in tropical sea surface temperature 4 6 c is larger than that indicated by foraminiferal mg ca 2 4 c we show that corals over estimate changes in sea surface temperature sst because their records are attenuated during skeletogenesis within the living tissue layer to quantify this process we microprofiled skeletal mass accumulation within the tissue layer of porites from australasian coral reefs and laboratory culturing experiments the results show that the sensitivity of the sr ca and 18o thermometers in porites will be suppressed variable and dependent on the relationship between skeletal growth rate and mass accumulation within the tissue layer our findings help explain why 18o sst sensitivities for porites range from 0 08 c to 0 22 c and are always less than the value of 0 23 c established for biogenic aragonite based on this observation we recalibrated the coral sr ca thermometer to determine a revised sensitivity of 0 084 mmol mol c after rescaling most of the published sr ca sst estimates for the indo pacific region for the last 14 000 years 7 c to 2 c relative to modern fall within the 95 confidence envelope of the foraminiferal mg ca sst records we conclude that two types of calibration scales are required for coral paleothermometry an attenuated porites specific thermometer sensitivity for studies of seasonal to interannual change in sst and importantly the rescaled 0 084 mmol mol c sr ca sensitivity for studies of 20th century trends and millennial scale changes in mean sst the calibration scaling concept will apply to the development of transfer functions for all geochemical tracers in corals

calcareous dunes of the united arab emirates and noah s flood the postglacial reflooding of the persian arabian gulf abstract aeolian dunes cover most of the united arab emirates and a large part of the eastern arabian peninsula although these sands as well as older aeolianites are largely composed of quartz there is a high percentage of detrital carbonate in them south of the persian arabian gulf for more than 40 km this percentage decreases inland these carbonate grains consist mainly of marine bioclastic fragments and calcareous ooids and were derived from the floor of the persian gulf which was exposed during low sea level of the last glacial period the postglacial rise in sea level rapidly reflooded the floor of the persian gulf cutting off the source for these aeolian sediments between 12 and 6 ka the sea transgressed more than 1000 km inundating the extended route of the tigris euphrates river and forcing people living on the exposed floor of the gulf to abandon their settlements because of the varying rate of eustatic sea level rise these waters at times flooded across the flat floor of the persian gulf at more than a kilometer per year we proposed that the stories of a great flood recorded in the bible as noah s flood and in babylonian history on clay tablets excavated in the tigris euphrates delta as the epic of gilgamesh are a record of this rapid postglacial flooding of the floor of the persian gulf

the environmental context of paleolithic settlement at jebel faya emirate sharjah uae abstract key to the understanding of pleistocene human dispersals and settlement dynamics is knowledge about the distribution of human habitats in space and time to add information about the characteristics of inhabited environments along the south arabian dispersal route this paper presents paleo environmental data from deposits excavated at jebel faya fay ne1 in the emirate of sharjah uae the sedimentary sequence at fay ne1 spans a period of about 125 000 years including the last interglacial and the holocene particle size and phytolith content of samples from two sediment columns were analyzed including both archaeology bearing layers and archaeologically sterile layers the results demonstrate that human occupation of the site is related to pluvial periods assemblage c dated to about 127 123 ka was deposited during a wet phase with an environment characterized by an increased proportion of c 3 grasses grassland with sedges but lacking tree cover characterize ecological conditions during the youngest of the paleolithic occupation periods assemblage a dated to about 45 40 ka environmental conditions during periods lacking archaeological remains are characterized by the absence of vegetation cover during phases of desiccation there is no evidence for human presence at the site between 38 and 11 ka

relative sea level changes glacial isostatic modelling and ice sheet reconstructions from the british isles since the last glacial maximum while contributing 1 m equivalent eustatic sea level rise the british isles ice sheet produced glacio isostatic rebound in northern britain of similar magnitude to eustatic sea level change or global meltwater influx over the last 18 000 years the resulting spatially variable relative sea level changes combine with observations from far field locations to produce a rigorous test for quantitative models of glacial isostatic adjustment local ice sheet history and global meltwater influx after a review of the attributes of relative sea level observations significant for constraining large scale models of the isostatic adjustment process we summarise long records of relative sea level change from the british isles and far field locations we give an overview of different global theoretical models of the isostatic adjustment process before presenting intercomparisons of observed and predicted relative sea levels at sites in the british isles and far field for a range of earth and ice model parameters in order to demonstrate model sensitivity and the resolving power available from using evidence from the british isles for the first time we show a good degree of fit between relative sea level observations and predictions that are based upon global earth and ice model parameters independently derived from analysis of far field data with a terrain corrected model of the british isles ice sheet that includes extensive glaciation of the north sea and western continental shelf that does not assume isostatic equilibrium at the last glacial maximum and keeps to trimline constraints of ice surface elevation we do not attempt to identify a unique solution for the model lithosphere thickness parameter or the local scale detail of the ice model in order to provide a fit for all sites but argue that the next stage should be to incorporate an ice sheet model that is based on quantitative glaciological model simulations we hope that this paper will stimulate this debate and help to integrate research in glacial geomorphology glaciology sea level change earth rheology and quantitative modelling copyright 2006 john wiley sons ltd

a geochemical study on the bitumen from dosariyah saudi arabia tracking neolithic period bitumen in the persian gulf this paper presents the results of a series of geochemical analysis conducted on 20 bitumen samples from the neolithic site of dosariyah eastern province saudi arabia the aim of this study was to establish the geological origin of this bitumen in order to identify the bitumen seepage they were extracted from the majority of the samples could be successfully related to bitumen seepages of northern iraq two samples didn t match the bulk of the samples and probably came from the burgan hill seepage kuwait three samples were too badly degraded in order to deliver reliable data and were removed from the dataset these conclusions stand in contrast with h3 as sabiyah a site culturally and geographically linked with dosariyah which bitumen came exclusively from the burgan hill in this paper we argue that this difference may be explained by the difference in dating between the two sites as h3 as sabiyah slightly predates dosariyah