short paper the palynology and correlation of the walton crag read crag formation pliocene the basal sands of the red crag formation at walton on the naze essex contain a pollen assemblage dominated by pinus and with pollen of taxodiaceae and thermophilous trees this is comparable with assemblages from the dutch reuverian c late pliocene it is not closely comparable with spectra from other sections previously correlated with the red crag formation at walton which arguably have praetiglian affinities dinoflagellate cysts typical of warm temperate water are also present and compare well with assemblages from the red crag formation in the southern north sea the pre ludhamian and waltonian are therefore separate stages assignable to the pleistocene and pliocene respectively the base of the walton crag the lowest division of the red crag formation at walton on the naze was long considered to be the local base for the pleistocene in the british isles largely because of the presence of supposedly characteristic pleistocene mammal fossils such as mammuthus meridionalis equus sp and hipparion sp boswell 1952 mitchell et al 1973 funnell west 1977 harland et al 1982 other opinion zagwijn 1974 funnell in curry et al 1978 cameron et al 1984 would attribute the red crag formation to the late pliocene on the grounds of mollusc and foraminifer correlation with belgian and dutch pliocene sequences the foraminifers from the red crag formation at walton on the naze are closely comparable with those from the crag in the lower part of the stradbroke borehole beck et al 1972 funnell west 1977 pollen assemblages from the same unit in the stradbroke borehole were dominated by

the structure and evolution of the wessex basin southern england an example of inversion tectonics abstract the wessex basin of southern england consists of four main sub basins each sub basin is thought to be fundamentally controlled by the normal reactivation of hercynian basement thrust and wrench or transfer faults post hercynian polyphase reactivation of both east west thrust and northwest southeast transfer faults tended to compartmentalise the basement thereby leading to the initiation of discrete permian cretaceous depocentres while rifting was confined to the western portions of the area during the permo triassic easterly migration in the mesozoic allowed the initiation of the weald and channel basins the sub basins represent therefore simple sinistral pull apart basins opening along northwest southeast faults this same fault direction is postulated to have also played a major role in controlling and or modifying the development of european basins in general major pre aptian uplift and erosion is largely attributed to the thermal effects and hence the isostatic uplift of the basin associated with continental rifting of the bay of biscay and the north atlantic margins major inversion and hence basin destruction began in the late cretaceous early tertiary with the uplift of the channel weald and vale of pewsey basins and culminated in the oligocene miocene synchronous with the helvetic phase of alpine deformation wessex basin inversion was facilitated by the thrust reactivation of variscan faults above an intracrustal detachment surface the same surface which allowed upper crustal extension and hence basin initiation in the permo triassic the structural development of the wessex basin both during extension basin formation phase and compression inversion phase was ultimately controlled by the plate motion of africa relative to europe such plate motions successfully predict the observed nw se sinistral motion from the stephanian to the aptian e w sinistral motion during the aptian cenomanian and largely nw se dextral motion from the cenomanian to the present day

pliocene shallow water paleoceanography of the north atlantic ocean based on marine ostracodes abstract middle pliocene marine ostracodes from coastal and shelf deposits of north and central america and iceland were studied to reconstruct paleotemperatures of shelf waters bordering portions of the western boundary current system including the gulf loop current florida current gulf stream and north atlantic drift factor analytic transfer functions provided pliocene august and february bottom water temperatures of eight regions from the tropics to the subfrigid the results indicate 1 meridional temperature gradients in the western north atlantic were less steep during the pliocene than either today or during late pleistocene isotope stage 5e 2 tropical and subtropical shelf waters during the middle pliocene were as warm as or slightly cooler than today 3 slightly cooler water was on the outer shelf off the southeastern and mid atlantic coast of the u s possibly due to summer upwelling of gulf stream water 4 the shelf north of cape hatteras north carolina may have been influenced by warm water incursions from the western edge of the gulf stream especially in summer 5 the northeast branch of the north atlantic drift brought warm water to northern iceland between 4 and 3 ma evidence from the iceland record indicates that cold east greenland current water did not affect coastal iceland between 4 and 3 ma 6 middle pliocene north atlantic circulation may have been intensified transporting more heat from the tropics to the arctic than it does today

neogene evolution of the himalayan tibetan region constraints from odp site 758 northern ninetyeast ridge bearing on climatic change abstract magnetic susceptibility remanence and lithostratigraphic profiles for the neogene quaternary sequence at site 758 odp leg 121 on the northern ninetyeast ridge show distinct changes dated from biostratigraphy and detailed magnetostratigraphy at 17 5 10 4 10 0 8 8 6 5 5 4 5 1 2 7 2 5 1 9 and 1 2 1 1 ma these magnetic and lithologic changes appear to reflect changes in the supply and character of terrigenous material from the himalayan tibetan region resulting from changes in gradient of the ganges brahmaputra and probably the ancient indus drainage systems the sedimentary changes can be correlated with changes in uplift sensitive markers such as the oceanic 87 sr 86 sr ratio and monsoonal induced upwelling but not clearly so with sealevel variations we interpret these sedimentary changes therefore to primarily reflect changes in the tectonic evolution of the himalayan tibetan region the changes in the distal marine sedimentary record of the northern ninetyeast ridge are compared with isotopic control on the timing of himalayan tibetan tectonic phases and magnetostratigraphic control on their reflection in the proximal siwalik molasse record this comparison indicates that the distal ninetyeast ridge record can be used to detail and to place minimal age constraints on tectonic phases in the wider himalayan region and on evolution of the proximal molasse sequence with a time lag determined for the four earliest changes at less than 1 m y the changes at 17 5 ma and 5 4 5 1 ma can be interpreted in terms of the causative chain enhanced plate motion uplift and sedimentation change climatic change supporting arguments that the late cainozoic global climatic deterioration is driven by uplift of large plateaus such as the himalayan tibetan region and the western cordillera

mapping eastern north american vegetation change of the past 18 ka no analogs and the future the method of modern analogs and an extensive data base of modern and fossil pollen data were used to generate a new series of paleovegetation maps for eastern north america spanning the past 18 ka the maps illustrate the continuous nature of climate induced vegetation change and the development after about 10 ka of modern regional vegetation patterns before the holocene vegetation biomes without modern analogs were widespread in response to climate conditions without modern analogs and to a lesser extent to the rapidity of climate change over the last glacial interglacial transition this geological perspective suggests that possible future climate changes could force similarly complex changes in natural vegetation including the development of biomes without modern analogs

the prism pliocene palaeoclimate reconstruction time for a paradigm shift global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change but single temperature representations of the oceanic mixed layer for dat

stratigraphy and paleoceanography of pliocene deposits of karaginsky island eastern kamchatka u s s r abstract the lithology and paleontology of pliocene deposits from karaginsky island off eastern kamchatka peninsula u s s r are described in order to provide a paleoceanographic reconstruction of this region of the eastern north pacific ocean the stratigraphic sequence is divided into three suites the limimtevayamian the ust limimtevayamian and the tusatuvayamian which correspond to three standard pacific diatom zones the thalassiosira oestrupii neodenticula koizumi n kamtschatica and n koizumi the entire sequence is further subdivided into six members and 18 distinct beds on the basis of molluscan assemblages and three members and seven beds on the basis of benthic foraminiferal assemblages marine ostracodes are described from the limimtevayamian suite the marine invertebrate assemblages from karaginsky island provide evidence that 1 ocean water temperatures were warmer than today about 4 ma and again about 3 5 3 0 ma 2 several arctic atlantic species of molluscs and ostracodes migrated to the eastern north pacific between 4 2 3 0 ma presumably through the proto bering strait 3 many species found in the karaginsky island pliocene represent pacific taxa which migrated through the arctic into the north atlantic during the late pliocene

lower pleistocene dinoflagellate cyst foraminiferal and pollen assemblages in four boreholes in the southern north sea neogene and lower pleistocene stratigraphy in the southern north sea has been investigated in four i g s boreholes between east anglia and the netherlands the foraminifera of the red crag formation in borehole 81 51 are closely similar to upper pliocene assemblages in holland the overlying succession is clearly punctuated by unconformities in seismic profiles separating four early pleistocene formations in the boreholes and indicating intervals of significant stratigraphic hiatus offshore the westkapelle ground and smith s knoll formations correlate with thurnian and antian stage deposits in east anglia pollen spectra in the winterton shoal and yarmouth roads formations are similar to baventian and bramertonian assemblages in britain the autochthonous marine and allochthonous terrestrial microfauna and flora provide conflicting evidence of early pleistocene palaeoclimate the dinoflagellate cysts and foraminifera indicate that each formation was deposited in a warm temperate neritic environment the pollen record containing evidence of fluctuation between boreal and mixed coniferous deciduous regional forest cover suggests alternation between cool and warm temperate palaeoclimate

synthetic data on the paleogeographic history of northeastern atlantic and betic rifian basin during the neogene from brittany france to morocco abstract this paper presents the results of a synthetic compilation of the studies of neogene marine deposits recognized on the northeastern atlantic coast from morocco to northern france the shoreline fluctuations as well as the tectonic and climatic events are discussed regarding the following time intervals and eustatic cycles late oligocene tb1 4 cycle ca 25 22 7 ma aquitanian tb1 5 cycle 22 7 20 7 ma burdigalian tb2 1 2 cycles 20 6 16 5 ma langhian serravallian tb2 3 6 cycles 16 5 10 4 ma tortonian tb3 1 2 cycles 10 4 6 4 ma messinian tb3 3 4 pars cycles 6 4 5 3 ma and pliocene 5 3 1 8 ma marine upper chattian is well represented in the acquitaine basin france with various facies formed in a tropical climate during the acquitanian and the burdigalian the transgressions extended in wide neritic gulfs in france portugal spain and north of morocco the middle miocene transgression is well pronounced in the different areas in the betico rifian realm overthrusts are established and the flysch resorption is concluded at the end of that time during the upper miocene the marine realm is locally back from the preceding one outstanding events occured in the tectonic betico rifian basin the eastern part of which was affected by the mediterranean salinity crisis during the messinian finally in the pliocene most of the features of the modern palaeogeography are evidenced even when the coastal frontage of several areas is still affected by little transgressions

a quantitative micropaleontologic method for shallow marine peleoclimatology application to pliocene deposits of the western north atlantic ocean abstract a transfer function was developed to estimate summer and winter paleotemperatures for arctic to tropical regions of the western north atlantic ocean using fossil ostracode assemblages q mode factor analysis was run on ostracode assemblages from 100 modern bottom sediment samples from continental shelves of north america greenland and the caribbean using 59 ostracode taxa seven factors accounting for 80 of the variance define assemblages that correspond to frigid subfrigid cold temperate mild temperate warm temperate subtropical and tropical climatic zones multiple regression of the factor matrix against observed february and august bottom temperatures yielded an astracode transfer function with an accuracy of about 2 c the transfer function was used to reconstruct middle pliocene 3 5 3 0 ma shallow marine climates of the western north atlantic during the marine transgression that deposited the yorktown formation virginia and north carolina the duplin formation south and north carolina and the pinecrest beds florida middle pliocene paleowater temperatures in virginia averaged 19 c in august and 13 5 c in february about 5 c to 8 c warmer than at comparable depths off virginia today august and february water temperatures in north carolina were 23 c and 13 4 c in south carolina about 23 c and 13 5 c and in southern florida about 24 6 c and 15 4 c marine climates north of 35 n were warmer than today south of 35 n they were about the same or slightly cooler thermal gradients along the coast were generally not as steep as they are today the north atlantic transfer function can be applied to other shallow marine pliocene and pleistocene deposits of eastern north america

trace element mobility during spheroidal weathering of basalts and andesites in hawaii and guatemala abstract trace element mobility has been studied in spheroidally weathered corestone shell complexes developed on late tertiary and quaternary volcanic rocks the parent materials are basalts and andesites related to 1 a subduction zone tecuamburro and moyuta volcanoes guatemala and 2 a hot spot hawaiian islands of oahu maui and hawai i the initial major element compositions are largely preserved in the corestones each corestone sample shows major element abundances characteristic of the different magmatic processes through which the lavas were generated however the changes in trace element compositions due to weathering show similar patterns in the corestone shell complexes independent of the tectonic setting and age element mobility within the different corestone shell complex was determined using an isovolumetric reference frame in this method bulk density is chosen as an independent measure of the extent of weathering based on volumetric concentrations the notion of element immobility cannot be applied to all the corestone shell complexes elements commonly assumed to be immobile e g zr ti and al vary in volumetric concentration for some corestone shell complex despite petrographic evidence of only minor weathering two corestones oahu and tecuamburro have become enriched in ree 3 relative to other lava flows from the same volcanoes and display negative ce anomalies the exfoliated shells from these complexes tend to have lower concentrations of ree 3 and have positive ce anomalies the fractionation of ce from the other rare earth elements ree is inferred to be a manifestation of changes in the valence state of ce from trivalent to tetravalent under oxidizing conditions in settings where the development of corestone shell complex is advanced an acidic solution can mobilize trivalent ree leach them out of more extensively weathered materials and transport them to less acidic portions of the regolith undergoing incipient weathering the precipitation of the ree 3 in the rinds and centers of the corestones are likely due to increases of the ph of the weathering solution systematic weathering induced ree behavior enrichment of most ree with lesser ce enrichment resulting in a negative ce anomaly can be discerned even in corestone samples that exhibit major element abundances and petrographic features otherwise similar to unweathered basalts and andesites

micropaleontological evidence for increased meridional heat transport in the north atlantic ocean during the pliocene the middle pliocene approximately 3 million years ago has been identified as the last time the earth was significantly warmer than it was during the last interglacial and holocene a quantitative micropaleontological paleotemperature transect from equator to high latitudes in the north atlantic indicates that middle pliocene warmth involved increased meridional oceanic heat transport

quantitative interpretation of fossil pollen spectra dissimilarity coefficients and the method of modern analogs abstract dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples how eight coefficients responded to differences among modern pollen samples from eastern north america was tested these coefficients represent three different classes 1 unweighted coefficients that are most strongly influenced by large valued pollen types 2 equal weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types and 3 signal0to noise coefficients that are intermediate in their weighting of pollen types the studies with modern pollen allowed definition of critical values for each coefficient which when not exceeded indicate that two pollen samples originate from the same vegetation region dissimilarity coefficients were used to compare modern and fossil pollen samples and modern samples so similar to fossil samples were found that most of three late quaternary pollen diagrams could be reconstructed by substituting modern samples for fossil samples when the coefficients indicated that the fossil spectra had no modern analogs then the reconstructed diagrams did not match all aspects of the originals no modern analogs existed for samples from before 9300 yr b p at kirchner marsh minnesota and from before 11 000 yr b p at wintergreen lake michigan but modern analogs existed for almost all holocene samples from these two sites and brandreth bog new york

covariance patterns of foraminiferal dgr18o an evaluation of pliocene ice volume changes near 3 2 million years ago oxygen isotope data for a pliocene interval from 3 6 to 2 8 million years ago show a mean increase 0 5 per mil of benthic delta 18 o at about 3 2 million years ago whereas planktic delta 18 o does not increase this lack of covariance indicates that the event at 3 2 million years did not result in a permanent increase in the ice budget of either the northern or the southern hemisphere

the beginning of the ice age in europe and its major subdivisions abstract the time range of the quaternary is discussed in terms of the view that this period is essentially the one in the earth s history in which during certain intervals inland ice developed in the northern hemisphere this process first became evident about 2 3 ma bp since then the quaternary thus defined has witnessed many climatic variations although for practical reasons it is not feasible to assign the status of stage to each distinclty warm or cold phase climatic change is nevertheless the most appropriate basis for world wide correlation it seems possible to use both climatic change and other correlation parameters to arrive at a practicable subdivision of the quaternary period into stages before about 1 ma vegetational succession during interglacials in western europe differed from that seen in later times a possible cause for this divergence is discussed in the later part of the quaternary after about 1 ma two distinct types of warm temperate intervals occurred one associated with high sea levels and an oceanic climate the other showing lower sea levels and a cooler and more continental climate the difference between these two types is shown by comparison of the distribution of abies during these time intervals

the molluscan fauna of the coralline crag pliocene zanclean at raydon hall suffolk uk palaeoecological significance reassessed abstract this study assesses the environmental implications of a quantitative study of the unusually well preserved molluscan fauna of over 200 species about 47 extinct from six samples from both the ramsholt and sudbourne members of the coralline crag formation at a british geological survey borehole at raydon hall near orford suffolk uk it reveals a shallow shelf fauna locally transported from a variety of habitats dominated by infaunal species spisula turritella abra amyclina from relatively fine sediments plus epifauna especially heteranomia possibly in part originating from nearby bryozoan communities as well as dead bivalve shells there was a small but consistent component of deeper water elements such as limopsis and a lack of strictly littoral species overall a water depth of about 50 m is suggested with bottom temperatures at times perhaps warmer than the present southern north sea but not as high as the modern mediterranean and a more oceanic setting this is in contrast to inferences from previous nineteenth century studies of coralline crag molluscs which viewed it as largely mediterranean in character but understated the regular presence of boreal forms such as arctica current interpretations still have to account for the coexistence of some lusitanian or mediterranean molluscan taxa alongside the cooler water elements

vertical seismic wave gradiometry application at the san andreas fault observatory at depth abstractwe have developed vertical seismic wave gradiometry vswg to estimate velocity impedance and attenuation structure in the vicinity of boreholes using borehole array waveforms of check shot explosions near the borehole head we have extended wave gradiometry wg theory from a purely local relation of the wavefield and wavefield spatial gradient to one that incorporated the ray ansatz over the length of the borehole for a traveling wave in a vertically inhomogeneous medium we checked the ray assumption against acoustic full wave synthetic seismograms and it was found to yield robust measures of the medium velocity anelastic attenuation and impedance structure trade off but in cases of high anelastic attenuation realistic bounds can be placed on the seismic impedance that effectively constrains the average attenuation we have applied these methods to data collected at the san andreas fault observatory at depth borehole in central california in 2005 and we found that the wg velocity estimat

northeastern atlantic and arctic faunal provinces based on the distribution of recent ostracod genera the benthonic ostracod communities of 93 recent northeast atlantic shallow marine sites have been studied the ostracod assemblages from 76 of these sites were previously undescribed while an additional 17 sites predominantly from british stations were assessed from the available literature excluding mesohaline genera a total of 102 podocopid ostracod genera were recognized on the northeast atlantic shelf between the niger delta and the barents sea using both semi quantitative most northerly and southerly occurrences of genera and quantitative q mode analysis site site methods it becomes apparent that ocean currents and water mass temperature exact a considerable control on the spatial latitudinal distribution of benthonic ostracoda at the generic level it has been demonstrated that the majority of northeast atlantic shelf ostracoda are restricted to one or several zoogeographical regions or provinces nigerian most southerly liberian sierra leonian guinean mauritanian moroccan lusita

high resolution late pliocene sea surface temperature record from the northeast atlantic ocean abstract application of quantitative micropaleontologic methods of sea surface temperature sst estimation to the planktic foraminiferal faunas at hole 548 in the northeast atlantic between 3 5 and 2 0 ma provide a detailed record of pliocene surface temperature changes during the onset of major northern hemisphere glaciation sst estimates indicate a relatively warm interval of enhanced interglacials warm peaks between 3 2 and 2 8 ma followed by steady cooling with a significant step like change toward colder temperatures occurring about 2 4 ma this record compares well with faunal and sst records from other north atlantic sites

quaternary paleoceanography of the deep arctic ocean based on quantitative analysis of ostracoda abstract ostracodes were studied from deep arctic ocean cores obtained during the arctic 91 expedition of the polarstern to the nansen amundsen and makarov basins the lomonosov ridge morris jesup rise and yermak plateau in order to investigate their distribution in arctic ocean deep water aodw and apply these data to paleoceanographic reconstruction of bottom water masses during the quaternary analyses of coretop assemblages from arctic 91 boxcores indicate the following ostracodes are common at all depths between 1000 and 4500 m and species distribution is strongly influenced by water mass characteristics and bathymetry quantitative analyses comparing eurasian and canada basin assemblages indicate that distinct assemblages inhabit regions east and west of the lomonosov ridge a barrier especially important to species living in lower aodw deep eurasian basin assemblages are more similar to those living in greenland sea deep water gsdw than those in canada basin deep water two upper aodw assemblages were recognized throughout the arctic ocean one living between 1000 and 1500 m and the other having high species diversity at 1500 3000 m downcore quantitative analyses of species abundances and the squared chord distance coefficient of similarity reveals a distinct series of abundance peaks in key indicator taxa interpreted to signify the following late quaternary deep water history of the eurasian basin during the last glacial maximum lgm a gsdw aodw assemblage characteristic of cold well oxygenated deep water 3000 m today inhabited the lomonosov ridge to depths as shallow as 1000 m perhaps indicating the influence of gsdw at mid depths in the central arctic ocean during termination 1 a period of high organic productivity associated with a strong inflowing warm north atlantic layer occurred during the mid holocene several key faunal events indicate a period of warming and or enhanced flow between the canada and eurasian basins a long term record of ostracode assemblages from kastenlot core ps2200 5 1073 m water depth from the morris jesup rise indicates a quasi cyclic pattern of water mass changes during the last 300 kyr interglacial ostracode assemblages corresponding to oxygen isotope stages 1 5 and 7 indicate rapid changes in dissolved oxygen and productivity during glacial interglacial transitions

a chronology of pliocene sea level fluctuations the u s middle atlantic coastal plain record abstract the sequence of marine and marginal marine silts and sands of the u s middle atlantic coastal plain preserves a relatively complete record of pliocene sea level highstands a general chronology for the deposition of these units has been developed previously from studies of the microfossil biostratigraphy complemented by a limited number of paleomagnetic and radiometric dates within this broad temporal framework it is currently difficult to assign ages to individual transgressive events with a resolution much better than 0 5 ma the age model proposed here attempts to refine the depositional history of the atlantic coastal plain by correlation with the more continuous deep ocean record the model assigns probable ages to the pliocene transgressions onto the atlantic coastal plain based on evidence for sea level highstands inferred from high resolution deep ocean 18 o records at least five major transgressive regressive events can be correlated with presumed eustatic fluctuations the temporal resolution for the timing of the transgressive events is greatly improved over that of the biostratigraphy alone many aspects of the proposed chronology require verification by more detailed field study but it is offered as a testable working hypothesis

pliocene palaeotemperature reconstruction for the southern north sea based on ostracoda abstract the development of a large northeastern atlantic shelf ostracod database has confirmed that an intrinsic relationship exists between watermass temperature and the spatial latitudinal distribution of benthonic shelf ostracoda a second pliocene ostracod database using assemblages from four boreholes in the netherlands and a number of localities from the east anglian neogene succession has also been constructed a quantitative method of modern analogues and the squared chord distance dissimilarity coefficient has been employed as a means of calculating the level of similarity between recent and neogene assemblages and therefore to aid in the reconstruction of palaeotemperatures in the southern north sea basin during the pliocene the results in the form of contoured dissimilarity values indicate the presence of at least seven palaeoceanographical climatic phases between ca 5 2 and 1 6 ma bp an early pliocene cooling phase ecozone a in which the fauna is dominated by the cryophilic species palmenella limicola norman elofsonella concinna jones robertsonites tuberculatus sars neomonoceratina tsurugasakensis tabuki and acanthocythereis dunelmensis norman supervenes a period of stable subtropical conditions in the miocene a mid pliocene warming phase ecozone b which has been documented throughout the north atlantic can be recognized in the faunal composition of the sublittoral ostracod assemblages of both the netherlands and east anglia a hiatus between the coralline and waltonian crags is thought to be associated with a deterioration in climatic conditions recent analogues to the netherlands faunas of ecozone c first phase late pliocene cooling ca 2 9 ma bp indicate a decrease of approximately 5 6 c in mean summer surface temperatures a return to elevated temperatures of a mauritanian aspect can be seen in the fauna of the fa2 zone and waltonian crag this amelioration of climate occurred prior to the praetiglian cold phase second phase late pliocene cooling ca 2 4 ma bp which again saw the reintroduction of cryophilic species including baffinicythere howei hazel fimarchinella logani brady crosskey and robertson and hemicythere emarginata sars into the southern north sea during the newbournian and butleyan stages the final phase of the latest pliocene third phase late pliocene cooling is only documented in the ostracod fauna of the norwich crag evidence in the covariance of loxoconchidae and norwegian provincial cryophilic species indicates that the polar front may have been as much as 2000 km further south during the deposition of the chillesford sand member norwich crag fm ca 2 0 1 6 ma bp