a palynofacies study of past fluvio deltaic and shelf environments the oligocene miocene succession north sea basin a reference data set for similar cenozoic systems abstract correct interpretations of depositional environments are fundamental for evaluating the geological history of a sedimentary basin palynofacies analyses are a valuable supplement to sedimentological and seismic studies in order to develop a palynofacies reference dataset for fluvio deltaic and shelfal successions a study of the assemblages of sedimentary organic particles from seven different well defined depositional environments within the uppermost oligocene lower miocene succession onshore denmark eastern north sea basin has been performed the study deals with the following environments floodplain lagoon washover fan flat prodelta shoreface offshore transition and shelf the sedimentary organic particles were grouped into four major categories 1 structured wood particles 2 amorphous organic matter aom in the present study mainly consisting of partly degraded vitrinite 3 cuticle and membranes and 4 palynomorphs the palynomorphs were grouped into eight subcategories 1 microspores 2 non saccate pollen 3 bisaccate pollen 4 botryococcus 5 other freshwater algae 6 fungal hyphae and spores 7 acritarchs and 8 organic walled dinoflagellate cysts a combination of a univariate box plots and a multivariate principal component analysis pca of the palynofacies data clear revealed the quantitative characteristics and variations within each discrete environment as well as their principal similarities and differences in spite of some natural overlaps for example between the lagoon and offshore transition environments the data revealed distinct characteristics e g a strong dominance of wood particles in the shoreface environment a strong dominance of bisaccate pollen in the washover fan flat environment and a near absence of dinocysts in the floodplain environment an overall increase in relative abundances of dinocysts and a decrease in abundances of non saccate pollen in the proximal distal trend were also outlined this study outlines a palynofacies reference dataset that can be used as a tool for interpreting depositional environments in equivalent settings preferentially combined with other information such as seismic data well logs and or lithology

pleistocene pollen stratigraphy from borehole 81 34 devil s hole area central north sea abstract twelve pollen assemblage zones are identified in a 229 m deep borehole bh 81 34 from the devil s hole area in the central north sea british sector the sediment from this borehole is early to late pleistocene in age and the observation of massulae from azolla filiculoides in sediment with reversed polarity indicates an age younger than the olduvai geomagnetic event for the entire sequence the early pleistocene sediments were at least partly deposited in the vicinity of a river outlet and can be correlated either with the eburonian or the menapian cold stage and with the bavel interglacial and the linge glacial within the bavelian stage in the dutch stratigraphy the middle pleistocene sequence contains an interval rich in abies picea and pinus probably deposited during the end of either cromerian complex interglacial iv noordbergum or possibly the holsteinian the uppermost 80 m of the core contains high frequencies of pre quaternary and deteriorated palynomorphs indicating extensive glacial or glaciofluvially reworked sediment

regional scale distributions of pollen and spore assemblages in alluvium around the bohai sea an essential step toward understanding marine palynological sources in china abstract to better understand the provenance and transport paths of modern pollen and spores in the bohai sea we analyzed 104 surface alluvial samples from its sixteen inflowing rivers and 56 modern surface pollen samples from around bohai sea in the east asia surface pollen database our results revealed that the pollen assemblages of the inflowing rivers were dominated by non arboreal pollen types which accounted for an average of 60 of the pollen and were represented primarily by chenopodiaceae the percentages of arboreal pollen reached an average of 23 fern spores accounted for the lowest percentage of the spores and pollen the characteristics of the pollen assemblages in the alluvium of the inflowing rivers especially large rivers reflected the vegetation of upstream sampling points rather than the characteristics of the vegetation around the sampling points the vegetation types represented by the pollen and spores in the short source rivers or seasonal rivers were beyond the range of the drainage basin especially the trees and ferns and differences of the watershed vegetation of the inflowing rivers led to different pollen assemblages in the alluvium in the study area the yellow river is the main source of modern surface pollen in the bohai sea unlike the pollen of the inflowing rivers the pollen assemblages in the bohai sea were dominated by arboreal pollen especially pinus the fern spores were dominated by selaginella but non arboreal pollen accounted for relatively low percentages of the pollen

a weathering intensity index for the australian continent using airborne gamma ray spectrometry and digital terrain analysis abstract weathering intensity largely controls the degree to which primary minerals are altered to secondary components including clay minerals and oxides as weathering intensity increases there are changes in the hydrological geochemical and geophysical characteristics of the regolith thus once calibrated weathering intensity can be used to predict a range of regolith properties a weathering intensity index wii over the australian continent has been developed at a 100 m resolution using regression models based on airborne gamma ray spectrometry imagery and the shuttle radar topography mission srtm elevation data airborne gamma ray spectrometry measures the concentration of three radioelements potassium k thorium th and uranium u at the earth s surface the total gamma ray flux dose is also calculated based on the weighted additions of the three radioelements regolith accounts for over 85 of the australian land area and has a major influence in determining the composition of surface materials and in controlling hydrological and geomorphological processes the weathering intensity prediction is based on the integration of two regression models the first uses relief over landscapes with low gamma ray emissions and the second incorporates radioelement distributions and relief the application of a stepwise forward multiple regression for the second model generated a weathering intensity index equation of wii 6 751 0 851 k 1 319 relief 2 682 th k 2 590 dose the wii has been developed for erosional landscapes but also has the potential to inform on deposition processes and materials the wii correlates well with site based geochemical indices and existing regolith mapping interpretation of the wii from regional to local scales and its application in providing more reliable and spatially explicit information on regolith properties are described

land use change and erosional history in a lake catchment system on the canadian prairies abstract the introduction of agriculture in the late 1800s and early 1900s brought about many changes in the natural prairie landscape of western canada the objective of this research project is to evaluate landscape response to land use change by relating observed changes in the sedimentary record of a lake drainage basin to documented land use change that has occurred since the onset of settlement a 52 cm lake sediment core was sectioned into 1 cm layers the sediment was separated into allogenic and authigenic fractions using a wet chemical extraction technique close interval 210pb dating enabled the calculation of sediment and elemental influx rates prior to european settlement erosion rates were low

late glacial holocene paleoclimatic and paleoceanographic evolution of the aegean sea micropaleontological and stable isotopic evidence abstract late glacial to holocene paleoclimatic and paleoceanographic changes are examined using records of calcareous and organic walled marine microfossils pollen and terrestrial spores and oxygen isotope data in cores from the aegean sea basins planktic foraminiferal coccolith and dinoflagellate data show that the late glacial holocene transition in the region was associated with a large warming of surface water mediterranean based paleotransfer functions for planktic foraminifera show a 5 10 c increase in surface water temperature from 14 000 to 9600 yr b p estimates of surface water oxygen isotopic composition 18 o w derived from planktic foraminiferal oxygen isotopic and transfer function data indicate that this warming was associated with a 2 0 to 2 5 reduction in 18 o w transfer function results indicate corresponding 1 0 to 1 5 salinity reductions for this tim ca 6400 9600 yr b p throughout the aegean sea pollen dinoflagellate and isotopic data show that the early holocene excess fresh water originated from rapid melting of the northern european and siberian ice sheets supplied primarily from the black sea by the opening of bosphorus and dardanelles channels during the post glacial sea level rise and supplemented by major rivers entering the aegean sea continuous outflow of fresh water into the aegean sea provided a low salinity surface lid preventing the ventilation of the deep water benthic foraminifera shows a major turn over that indicates low dissolved oxygen however bottom waters were not anoxic sapropel level s1 resulted from a combination of stagnant deep water in isolated depressions increased terrigenous organic matter and periods of high primary productivity as indicated by pollen and dinocysts respectively the surface water temperature and salinity reached present day values at 6400 yr b p with little subsequent change despite the major deforestation onshore

palynological evidence of climatic and oceanographic changes in the north sea during the last deglaciation abstract palynological analyses performed on cores from the norwegian channel troll 8903 led to reconstruction of the late glacial variations in sea surface conditions using dinoflagellate cyst data and permitted direct correlation with the vegetation history of northwestern europe derived from pollen assemblages by 15 000 yr b p ice rapidly receded from the norwegian shelf and relatively warm summer conditions prevailed in surface waters a first late glacial cooling marked by extensive seasonal sea ice cover is dated at ca 13 600 13 00014c yr b p which coincides with the oldest dryas interval during the bolling allerod interval a rise in sea surface temperature both in february up to 3 c and august up to 15 c led to the establishment of ice free conditions in the northern north sea while pollen data reveal a densification of the vegetation cover the beginning of the younger dryas interval is marked by an increase in nonarboreal pollen input indicative of the opening of the forest vegetation cover concomitant with a cooling of surface waters during winter and development of sea ice cover however sea surface conditions remained relatively warm in summer until about 10 300 yr b p when extremely cold conditions and extensive sea ice cover developed up to 7 months yr improving conditions are recorded in surface waters by 10 100 yr b p a few hundred years before the development of forest cover onshore as shown by the pollen record such a discrepancy between marine and terrestrial indicators at the end of younger dryas time suggests a delayed response of the vegetation to regional climate warming

micropaleontology and palynology of core par87a 10 a 23 000 year record of paleoenvironmental changes in the gulf of alaska northeast north pacific micropaleontological data of core par87a 10 reveal that the last glacial interval prior to 13 ka was marked by low biogenic fluxes and poor caco3 preservation quantitative estimates of sea surface conditions based on dinocyst assemblages suggest that cold temperatures and freezing winter conditions existed during this period the glacial to interglacial transition i e the 13 8 ka interval was characterized by an increase in fluxes of microfossils indicating enhanced productivity in surface waters a higher biogenic carbonate production probably resulted in better preservation of caco3 this interval was marked by relatively low salinity and by sea surface temperatures increasing toward modern values relatively high pollen flux during the transition suggests nutrient inputs through atmospheric and or fluvial transport from the adjacent north american continent after 8 ka diminished fluxes of plankton concomitant with a decline in pollen input are associated with decreasing nutrient supply as predominantly eastward winds became established over the north pacific

a sea level curve for the canadian beaufort shelf radiocarbon dated peat and peaty clay samples from geotechnical boreholes in the canadian beaufort continental shelf have been used to reconstruct a late quaternary relative sea level rsl curve the samples were carefully selected and evaluated using palynological techniques to ensure that reasonable age error limits could be given to each sample the dated samples were then related to the local geological setting using seismic profiles to determine the environment of deposition the resulting data show a rise of 140 m in rsl since 27 000 years bp a minor lowering of rsl at some time between 20 000 and 10 000 years bp is inferred from acoustic data contributions from basin subsidence sediment loading and consolidation account for 35 m of the total rsl rise the rsl curve is interpreted in the light of recent models of the isostatic and eustatic responses of the earth s crust at the laurentide ice sheet margin ice may have been more extensive during the middle wisconsinan than previously thought a

late quaternary glacial and sedimentary history of bonavista bay northeast newfoundland high resolution seismic profiles and core data from bonavista bay northeast newfoundland show that the sedimentary package above acoustic basement was deposited during the deglaciation of the late wisconsinan ice sheet during the late wisconsinan maximum 20 000 bp bonavista bay was occupied by a grounded ice sheet that extended farther offshore deglaciation of the bay was rapid and occurred prior to 13 500 bp during a time of rising sea level a basal till was deposited beneath the grounded ice and after lift off an ice shelf developed over the outer basins where diamicton was deposited the inner bay gradually deglaciated as the ice margin retreated to the present day shoreline by 13 000 bp and fine grained outwash sediments transported by interflows were rapidly deposited the inner bay remained under the influence of one or more remnant ice centres until 10 000 bp with ice positioned on the bonavista and gander peninsulas normal marine conditions were established in the outer bay by

pollen distribution in recent marine sediments eastern canada analysis of 90 samples from coastal and continental shelf areas off eastern canada between 42 and 69 n shows that quaternary pollen and spores are present in recent marine muds throughout this region pollen and spore concentrations range from 50 000 to 100 grains per cm3 and they decrease both offshore as a function of distance from vegetation sources and northwards as a function of lower vegetation density north of the summer arctic frontal zone isopercentage contours show that maximum relative abundances of most palynomorphs occur in marine sediments adjacent to their regions of highest vegetation representation onshore however pinus and picea pollen tend to increase in percentage abundance with distance offshore presence of these tree pollen in marine sediments off baffin island implies that wind transport is an important pathway by which bisaccate pollen types enter the ocean in addition to fluvial transport q mode factor analysis shows that four major factors account for 89 of the variance amo

late holocene environmental conditions in coronation gulf southwestern canadian arctic archipelago evidence from dinoflagellate cysts other non pollen palynomorphs and pollen boxcore 99lssl 001 68 0958 n 114 1868 w 211 m water depth from coronation gulf represents the first decadal scale marine palynology and late holocene sediment record for the southwestern part of the northwest passage the record was studied for organic walled microfossils dinoflagellate cysts non pollen palynomorphs pollen terrestrial spores and sediment characteristics 210 pb 137 cs and three accelerator mass spectrometry 14 c dates constrain the chronology three prominent palaeoenvironmental zones were identified during the interval ad 1470 1680 zone i the climate was warmer and wetter than at present and environmental conditions were more favourable to biological activity and northward boreal forest migration with reduced sea ice and a longer open water growing season the interval ad 1680 1940 zone ii records sea ice increase and generally cool polar conditions during the little ice age during ad 1940 2000 zone iii organic microfossils indicate an extended open water season and decreased sea ice with suggested amelioration surpassing that of zone i although more marine studies are needed to place this record into an appropriate context the succession from ameliorated zone i to cooler sea ice influenced conditions zone ii and finally to 20th century warming zone iii corresponds well with several terrestrial climatic records from the neighbouring mainland and victoria island and with lower resolution marine records to the west copyright 2011 john wiley sons ltd

late quaternary vegetation and climate change in southeastern australia palynological evidence from marine core e55 6 abstract palynological analysis of core e55 6 obtained from off shore western victoria provides a record of vegetation and climate change in the southeastern south australian and western victorian region spanning much of the last 125 000 yr an accompanying oxygen isotope record provides a chronology for the sequence the pollen record suggests that maximum effective precipitation occurred during the height of the last interglacial oxygen isotope substage 5e with wet sclerophyll forest and rainforest widespread in the region effective precipitation appears to have decreased during substage 5d promoting the expansion of dry sclerophyll communities then increased slightly during substage 5c with the limited re occurrence of wetter forest types climatic conditions gradually became drier from substage 5b with the replacement of eucalypt dominated forest by more open heath and mallee type communities in the arid glacial conditions of isotopic stage 4 a brief phase of increased effective precipitation occurred during the interstadial stage 3 with limited expansion of eucalyptus followed by a steady decline in effective precipitation and the expansion of open heath and grass communities pollen is very sparse in the top section of the core making environmental interpretation difficult nevertheless it appears that grass and heath communities dominated the region during stage 2 there is no clear record of the holocene due to the presence of mudflow sediments in the top of the core the pollen evidence also suggests that continental shelf exposed as sea levels fell was colonised by a mosaic of coastal vegetation including myrtaceae dominated scrub eucalypt and casuarina woodland asteraceae and chenopodiaceae dominated heath and grassland the charcoal record expressed as a ratio to pollen concentration gives evidence of increased burning during the height of the last interglacial period most likely in response to increased fuel loads with the expansion of eucalypt dominated forest this record also indicates a second phase of increased burning commencing in stage 2 which gives possible evidence for increased anthropogenic activity in the region

natural radionuclides in the soils of a small agricultural basin in the canadian prairies and their association with topography soil properties and erosion summary samples taken from the a and b horizons of the soil at 160 sites in a small 178 ha cultivated drainage basin in central saskatchewan were analysed by gamma spectroscopy to determine the concentration of a number of natural radionuclides in the soil the concentration of 40k the 238u daughters 226ra 214pb and 214bi and the 232th daughters228ac 212bi and 208tl was determined a variety of soil properties and topographic variables were measured at each sampling site earlier studies in the basin provided net soil erosion estimates i e net loss or gain for each site the association of isotope activities with topography soil properties and net erosion was evaluated mean isotope activities for the basin were very close to mean values reported earlier for native soils in southern saskatchewan differences in isotope concentrations between the a and b horizons of the soils were related to differences in the degree to which the different isotopes are taken up by plants isotope concentrations in the surface soil were inversely correlated with soil particle size variation in isotope activities within the basin appeared to be linked to soil redistribution by erosion but in a complex manner which reflects size sorting of soil particles by erosion processes erosion processes seem to be at least as important as leaching processes in determining the spatial distribution of natural radionuclides in the surface soils of the study area

magnetostratigraphy and palynology demonstrate at least 4 million years of arctic ocean sedimentation it has long been recognized1 2 that the arctic ocean has a major role in regulating the timing of northern hemisphere glaciations global heat exchange and ocean circulation several recent studies3 7 have attempted to interpret the palaeoclimatic record in sediment cores from the arctic ocean but conflicting ages have been reported for palaeoclimatic events dated by different methods3 6 to establish a consistent chronology for cores from the central arctic ocean we performed detailed palaeomagnetic and palynological studies of three cores collected7 near the crest of the alpha ridge and obtained radiocarbon dates from planktonic foraminifers isolated from 1 cm thick intervals magnetic inclination values for these cores clearly record normal and reversed polarity intervals that apparently correspond to the brunnes and matuyama magnetochrons the longest core also includes polarity intervals typical of the gauss and gilbert magnetochrons this chronology is confirmed by the first and last occurrences of pollen and dinoflagellate species that can be correlated with european8 9 and dsdp10 12 chronostratigraphies dated by standard biochronological methods micromass radiocarbon dates for foraminifers indicate a sedimentation rate of 1 mm per 1 000 yr we believe that these data confirm a long 4 myr chronology for the alpha ridge cores the lithostratigraphy of which can be correlated over extensive areas of the western arctic ocean2 7 and more important provide dinoflagellate and palynomorph data that indicate the validity of early chronology

isopollen maps for 18 000 years b p of the atlantic offshore of northwest africa evidence for paleowind circulation distribution patterns of the most important pollen types from southern european and northwest african source areas for the 18 000 years b p time slice are reconstructed from pollen records of 14 well dated deep sea cores located between 37 and 9 n and compared with the modern pollen distribution in this area it is concluded that the belt with maximum african easterly jet transport did not shift latitudinally during the last glacial interglacial transition but remained at about 20 n furthermore it is substantiated that the trade winds did not shift latitudinally during the last glacial interglacial transition this evidence is not compatible with an atmospheric circulation model that assumes a zone of surface westerlies in the northern part of northwest africa trade winds during glacial episodes did however intensify especially from about 36 to 24 n

paleoclimatic and paleoceanographic conditions leading to development of sapropel layer s1 in the aegean sea abstract sapropel s1 occurs as 25 35 cm thick black weakly laminated muds in aegean sea cores s1 was deposited between 9600 and 6400 yr b p during a period of isotopically depleted and relatively cool surface waters micro faunal and floral data indicate a major reduction in surface waters salinity during the deposition of s1 and oxygen isotopic data show a northerly fresh water source relatively light 13 c org and high pollen spore concentrations in s1 suggest increased influx of terrestrial organic carbon probably supplied by major rivers draining into the northern aegean sea benthic foraminifera indicate high nutrient low oxygen bottom waters for s1 and together with silt sized hematite and manganese coatings suggest that during the deposition of s1 surface sediments were oxic visual and xrd evidence of pyrite in s1 together with enrichments in s cu zn as ni cr and fe suggest that subsurface conditions were sufficiently reducing for so 4 2 reduction to occur probably by diffusion from surface oxic into subsurface anoxic sediments palynomorphs in s1 show large increases in terrestrial pollen and spores with the floral assemblage indicating significant influx from northern european rivers and minor african components associated with increased summer monsoonal rain abundance of dinoflagellates and amorphogen suggests some increase in primary productivity in response to increased influx of humic compounds however there is no evidence of upwelling the clay fraction in s1 shows notable decreases in smectite and kaolinite and reciprocal increases in illite and chlorite the combined data suggested that the evolution of s1 in the aegean sea largely resulted from stagnation of the surface waters during the final disintegration of the continental ice sheets rather than an increase in primary productivity and higher preservation of organic carbon on the sea floor

quantitative topographic analysis of gilgai soil morphology abstract for a gilgai soil complex we estimated the effect of overland and intrasoil substance flows on vertisol development using concepts of topographic control of lateral substance movement by gravity rather than direct observations and measurements of these processes first we studied relationships between gilgai microtopographic characteristics and some vertisol morphological properties namely depth to parent material c and calcium carbonate enriched bca horizons secondly we checked if microtopographic characteristics of the c horizon surface influence some vertisol properties by examining the bca horizon depth we used digital models of quantitative topographic variables we concluded that the dominant mechanism controlling the c horizon depth is pedoturbation also pedoturbation can be important in the development of the bca horizons however variations in the c and the bca horizon depths are not dictated by pedoturbation only our analysis showed that key factors influencing the c and the bca horizon depths are overland and intrasoil lateral migration and accumulation of water solution and solid substances the c horizon depth depends on the landsurface topographic characteristics namely horizontal vertical and mean curvatures specific catchment area topographic and stream power indices the bca horizon depth is significantly affected by the same set of topographic attributes of both the landsurface and the c horizon surface the bca and the c horizon depths as a rule depend more on specific catchment area topographic and stream power indices than on horizontal vertical and mean curvatures of the landsurface and the c horizon surface this is because specific catchment area topographic and stream power indices take into account a relative location of a point in a microcatena utilization of quantitative topographic variables allows us to explain 82 of variation in the bca horizon depth and to suggest that topography is the main factor in the bca horizon formation

pollen stratigraphy of late quaternary cores from marmara sea land sea correlation and paleoclimatic history marine pollen analysis is an important tool for paleoclimatic reconstruction of regions like the eastern mediterranean and near east where few onshore sites provide long pollen records first a compilation was made of core top data from the eastern mediterranean to blackseas to map regional variations in modern marine pollenspore concentrations these data show a strong linkbetween pollen spore concentrations and sea surface salinity with minima of 5 grains g in the southern mediterranean and maxima of 160 000 grains g in the blacksea despite under representation of some forest and herbaceous vegetation indicators e g fagus and pistacia variations in species composition of the marine assemblages correspond closely with the distribution of regional vegetation zones and can be used as proxies for spatial differences in seasonal and total temperature and rainfall pollen spore assemblages in five cores from the marmara sea with multiple ages ranging from 33 550 to 1990 yr bp and one holocene core from southeastern blacksea were used to compile a late quaternary marine pollen stratigraphy these data were then compared with eastern mediterranean onshore reference sites in order to reconstruct a vegetation and paleoclimate history for the blacksea aegean corridor from the pleniglacial interval to present five marine pollen zones are recognized pz 5 v33 6 24 ka corresponds to the late wu rm pleniglacial pz 4 v24 13 ka spans the late glacial maximum lgm pz 3 v13 10 2 ka includes the allero d younger dryas glacial interglacial transition pz 2 10 2 4 ka marks the early holocene interglacial warm wet interval and pz 1 covers the latest holocene colonization phase which may also have been cooler and drier using the steppe forest index of traverse 1975 it is shown that the only intervals of severely dry conditions occurred briefly during the lgm and its transition during most of the pleniglacial and all of the postglacial time precipitation versus evaporation rates were sufficiently high to permit persistence of oro mediterranean forest vegetation furthermore there is no evidence for environmental conditions in the blacksea marmara region that would have encouraged pastoral or agricultural settlement in the littoral region prior to the bronze age commencing 4600 years ago crown copyright a 2002 elsevier science b v all rights reserved

selective transport of palynomorphs in marine turbiditic deposits an example from the ascension monterey canyon system offshore central california abstract the pollen assemblage of a deep sea core 15g collected at lower bathyal depths 3491 m on a levee of monterey canyon off central california was investigated to gain insights into the delivery processes of terrigenous material to submarine fans and the effect this transport has on the palynological record thirty two samples were obtained down the length of the core 19 from hemipelagic and mixed mud deposits considered to be the background record and 13 others from displaced flow deposits the pollen record obtained from the background samples documents variations in the terrestrial flora as it adapted to changing climatic conditions over the last 19 000 cal yrs bp a q mode cluster analysis defined three pollen zones a glacial pollen zone ca 20 000 17 000 cal yr bp an overlying transitional pollen zone ca 17 000 11 500 cal yr bp and an interglacial pollen zone ca 11 500 cal yr bp to present another q mode cluster analysis of both the background mud and flow deposits also defined these three pollen zones but four of the 13 turbiditic deposits were assigned to pollen zones older than expected by their stratigraphic position this was due to these samples containing statistically significant fewer palynomorphs than the background muds as well as being enriched 10 35 in some cases in hydraulically efficient pinus pollen a selective bias in the pollen assemblage such as demonstrated here may result in incorrect interpretations e g climatic shifts or environmental perturbations based on the floral record indicating turbiditic deposits should be avoided in marine palynological studies particularly in the case of fine grained flow deposits that may not be visually distinct granulometry and grain size frequency distribution curves may not be enough to identify these biased deposits determining the relative abundance and source of displaced shallow water benthic foraminifera entrained in these sediments serves as an excellent additional tool to do so

latest pleistocene holocene paleoceanographic trends on the continental margin of eastern canada foraminiferal dinoflagellate and pollen evidence micropaleontological studies were made of cores from four shelf basins on the eastern canadian margin emerald and canso basins on the scotian shelf 44 46 n notre dame channel newfoundland shelf 50 n and cartwright saddle labrador shelf 55 events were correlated using a combination of14c dates and pollen stratigraphies surface and bottom water changes were compared on the basis of dinoflagellates and benthic foraminifera respectively the results indicate significant paleoceanographic shifts along a north south gradient both prior to and during the holocene distinct late pleistocene holocene paleoceanographic events were distinguished in the emerald canso and notre dame basins these events are less obvious in cartwright saddle which is in deeper water and further off shore pleistocene glaciomarine sediments in all basins contain a fauna dominated byelphidium excavatum f clavata dinoflagellates and pollen are rare or absent the widespreadelphidium fauna probably reflects turbid glacial meltwater and or a permanent ice shelf cover from 20 000 10 000 yrs bp the notre dame core also penetrates older sediment with an outer labrador current fauna which may represent a late wisconsinian interstade at about 23 000 yrs bp from 7 000 10 000 yrs bp a cold water fauna occurred which is similar to modern outer labrador current faunas from about 5000 7000 yrs bp a warm interval is indicated by a relatively warm water calcareous benthonic foraminiferal fauna and increased representation of typical gulf stream dinoflagellates the most recent change occurred in the last 2000 years with an abrupt cooling associated with stronger flow of the arctic inner labrador current this cooling event is marked by an increase in arctic dinoflagellates and by an exclusively agglutinated benthonic foraminiferal fauna at two sites canso and notre dame these holocene paleoceanographic changes are not clearly seen in the benthic fauna of the deep northern basin cartwright saddle although dinoflagellate data at this site indicate that surface water changes have occurred that are similar to those found in shallower basins shifts in the zonal position of the gulf stream and changes in the relative mass transports of the west greenland and labrador currents are mechanisms which may account for the paleoceanographic events the glacial interstadial glacial sequence recorded in the notre dame channel in conjunction with other theories on glacial triggering mechanisms provides biostratigraphic evidence which suggests the onset of a glacial stage in the near future

elements d une climatostratigraphie du pleistocene moyen et tardif dans l est du canada par l analyse palynologique et isotopique du forage 84 030 003 mer du labrador the piston and gravity cores 84 030 003 collected in the southern labrador sea have been sampled for detailed palynological and isotopic analyses the 18o record on foraminifera neogloboquadrina pachyderma left coiling indicates a stratigraphy spanning isotopic stages 8 to 1 i e over ca 300 000 years the isotopic record allows the calculation of a mean sedimentation rate of approximately 5 cm ka the pollen and spore contents of the sediments are low the low pollen influxes generally less than 1 grain cm2 per year and the dominance of pinus suggest aeolian transport over long distances with southwest northeast to south southwest north northeast trends dinoflagellate cyst concentrations are relatively low indicating a low regional phytoplanktonic productivity the assemblages are however diversified they reflect influences from the north atlantic drift and from the labrador current the occurrence of warm temperate to tropical impagidinium species in deposits suggests an almost permanent

terrestrial palynology from marine cores as an indicator of environmental change for the waipaoa sedimentary system and north eastern new zealand diverse terrestrial palynomorph assemblages of pleistocene to recent age have been recovered from mainly marine sediment cores along the eastern new zealand margin these assemblages record a range of environmental changes including climate deforestation reforestation rates of erosion sediment provenance and age volcanic activity polynesian and european settlement strength and direction of ocean currents astronomical cyclicity and other major events many of which can be correlated with shorter onshore terrestrial sequences as such pollen yields valuable information on the dynamic new zealand landscape which is of particular relevance to a source to sink approach this paper provides an integrated summary of published and unpublished late pleistocene palynological studies off eastern north island new zealand that gives context for an analysis of cores within and marginal to the waipaoa sedimentary system pollen assemblages faithfully reflect the last glacial vegetation dominated by grass and shrub land species together with elevated tertiary pollen from enhanced erosion of the regolith the glacial termination and holocene were marked by establishment of podocarp forest a mid holocene disappearance of sediment trapping mangroves and introduction of distal pollen with establishment of coastal current systems under rising sea level these natural signals are overprinted by abrupt changes in pollen species caused by volcanic eruptions finally endemic forest and shrub pollen were markedly reduced with human colonisation associated land use changes and introduction of exotic species

early devonian lochkovian early emsian bioevents and conodont response in the prague synform czech republic abstract the devonian succession of the prague synform is characterized by two major lithofacies shallow water biodetrital mostly crinoidal limestones that also include a reefal skeletal accumulation of pragian age and a more pelagic facies that is represented mostly by calcisiltites among the several devonian prominent sea level fluctuations some can be traced globally e g the basal pragian and kacak events in recent years conodont biostratigraphy of the early devonian lochkovian pragian and early emsian of the prague synform has been refined the regional subdivision of the lower devonian in its type area has been greatly improved by the integration of new biostratigraphic chemostratigraphic sedimentological and petrophysical data that has in turn strengthened global correlations for this interval in earth s history the complete conodont biozonation of the early devonian interval basal lochkovian earliest emsian in the prague synform includes 17 biozones which can be applied to sections representing various depositional environments and have more global applicability than previously proposed global conodont biozonations the zonal scale enables a precise biostratigraphic delimitation of the major early devonian biotic events silurian devonian boundary event lochkovian pragian event and basal zlichovian event there were major changes in the conodont fauna in response to the silurian devonian boundary and lochkovian pragian events however the basal zlichovian event was only characterized by a very gradual transition in the conodont fauna in parallel to the traditional events defined for the prague synform seven other significant conodont events have been documented these events represent major turnovers in the conodont fauna that have a direct impact on conodont biostratigraphy specifically at a global scale the icriodus and irregularis events are congruent with the lower boundaries of the lochkovian and pragian stages respectively the conodont events established in the prague synform largely reflect variations in the seawater depth but are generally independent of lithological changes within sections of the prague synform

palynomorphs in surface sediments of the north western black sea as indicators of environmental conditions abstract most previous black sea palynology studies have used pollen spore assemblages as proxies for climate and landscape changes and dinocyst assemblages as proxies for surface water salinity however there are few data on within region variations in these assemblages using large sets of surface samples and a full suite of palynomorphs including terrigenous pollen spores freshwater algal spores and organic remains of marine microplankton micro and meiobenthos here we fill this knowledge gap using results from a palynological study of 43 surface samples from water depths of 71 905 mbsl on the ukrainian shelf and adjoining continental slope nw black sea the palynology samples were collected in conjunction with water and sediment chemistry data grain size micropaleontological and meiobenthos data from the eu fp6 project hermes hotspot ecosystems research on the margins of european seas this dataset uniquely covers shelf and upper slope areas east and west of the odessa sinop fault zone osfz that delimits areas of lower and higher hydrocarbon gas contents respectively the new data show that on the wide shelf with a shallow ca 80 m oxycline pollen assemblages differ from classical models for marine pollen transport on the ukrainian shelf pollen concentrations are extraordinarily high far offshore and the grains are often pyrite infilled these features apparently reflect high pollen preservation potential in low oxygen sediments probably enhanced by cross shelf transport of land derived particulate organic matter the new data have important consequences for accurate modelling of carbon burial and storage in epicontinental seas and they provide a baseline for evaluating marine pollen concentrations expected to reflect the early neolithic farming on the ukrainian shelf furthermore although large concentrations of dinocysts comprise more than half of the total non pollen palynomorphs npp the high pollen concentrations skew the p d index pollen dinocyst ratio commonly used to evaluate changes in paleo shoreline proxy sea level positions despite the discharge of several large rivers to the ukrainian shelf there are negligible traces of freshwater algae in the hermes samples except at sta 15 where pediastrum is abundant overall palynomorphs of terrestrial origin make up about half 52 of the acid resistant organic walled particles on the outer nw black sea shelf and adjacent slope the abundances of the major micro and meiobenthic palynomorph groups show the same trends east and west of the osfz as the micropaleontological data reported for the hermes samples taken at the same sites the combined microzooplankton and zoobenthos surface assemblage data provide an important new baseline for evaluating historical and past changes in biodiversity and aquatic foodweb structure in the now polluted nw black sea comparison can also be made with foodweb reconstructions for permian black shales

pollen transport through distributaries and depositional patterns in coastal waters abstract in this study we compare seasonal pollen and spore assemblages in river waters from the mississippi river at vicksburg mississippi to those downstream at belle chasse louisiana and in a distributary the atchafalaya river at morgan city louisiana assemblages of pollen in waters at vicksburg and belle chasse are similar to each other but distinctively different from those in the atchafalaya river local pollen inputs are more important in the anastomosing atchafalaya river channel as compared to the meandering main stem mississippi channel which discharges through the bird foot delta riverine pollen and spore assemblages are also compared to those of surface sediments from the louisiana continental shelf in the vicinity of the mississippi river plume in this area the primary source of marine pollen and spore assemblages appears to be the discharge from the main stem mississippi with limited input from the atchafalaya thus pollen deposited in these coastal waters provides a record of vegetation in the mississippi drainage basin rather than local coastal areas pollen assemblages on the continental shelf vary with distance from the river source but not in a systematic manner the pattern is explained by biological controls on fine particle deposition in marine waters i e deposition of pollen in copepod fecal pellets as copepod grazing is dependent upon phytoplankton production pollen deposition from the river plume will be limited by high turbidities proximal to the river mouth we hypothesize that in neritic environments pollen is preferentially deposited in areas corresponding to high phytoplankton production which are characterized by reduced turbidity and high nutrient availability

upper cenozoic history of the labrador sea baffin bay and the arctic ocean a paleoclimatic and paleoceanographic summary foraminifera palynomorphs and stable isotopes in planktonic foraminifera have been studied in piston cores from the northern labrador sea southern baffin bay and the alpha ridge region of the central arctic ocean foraminifera in cores from the labrador sea and southern baffin bay show glacial interglacial 18o values similar to those reported from the norwegian and greenland seas in contrast to the eastern north atlantic ocean however peaks of subarctic foraminifera and dinoflagellates in the western north atlantic cores show that relatively warm atlantic surface water continued to flow into the northern labrador sea during the early glaciation growth phases of isotopic stages 2 4 6 and 8 boreal and subarctic pollen suggest that warm atlantic air flowed into the northern labrador sea and baffin bay during the ice sheet growth phases the advection of warm air masses and the presence of open waters during the summer probably provided moisture for the growth of the laurentide innuitian and greenland ice sheets isotopic and microfossil records in arctic cores can also be tentatively correlated with major high latitude north atlantic glacial interglacial events magnetostratigraphic palynological and amino acid dating however shows that sedimentation on the alpha ridge has been very slow during the past 0 73 m y therefore events of less than 20 000 years duration cannot be clearly discerned interpretation of pre pleistocene paleoenvironments is further limited by the sparseness of calcareous and siliceous microfossils

a mediterranean perspective on 10be sedimentation and climate around the matuyama brunhes boundary les liaisons dangereuses abstract the 10be 9be ratio is commonly employed as a tool for establishing the stratigraphic position of paleomagnetic excursions and reversals whenever the traditional paleomagnetic approach fails to provide conclusive results in particular it is held that 10be production rates in the atmosphere depend on the strength of the earth s magnetic field and the fallout and deposition of cosmogenic beryllium at the surface happen on a very short time scale however investigations performed on terrestrial and marine successions demonstrate that the 10be record and the paleomagnetic signal are often asynchronous mechanisms that control the conveyance and deposition of cosmogenic 10be to the seafloor are still ambiguous and poorly documented here we discuss the dynamics of 10be in a central mediterranean marginal marine depositional scenario characterized by a pervasive terrigenous influx our data show that a very close correlation exists between 10be concentrations and the local proxy of rainfall rates and regimes pollen indicating that a considerable 10be transport from the mainland may occur in response to the remobilization of terrestrial reservoirs during periods of increased runoff superimposed is a dynamic oceanographic setting that further controls the preservation potential of 10be at the bottom in terms of changing water chemistry and or composition of the sedimentary flux to the seafloor results of our investigation suggest that in particular environmental and depositional settings the interplay between climate terrigenous yield and oceanography may jeopardize the sedimentary depiction of the meteoric 10be contribution thus challenging the use of 10be for tracking the stratigraphic position of geomagnetic reversals

modern and late quaternary pollen spectra of fiord sediments eastern baffin island arctic canada abstract pollen spectra of thirty surface samples from baffin island fiords are dominated by abetula filicales cyperaceae gramineae association that is somewhat representative of local or regional vegetation however betula and filicales are over represented andsalix cyperaceae and ericales are under represented compared to their importance in the present vegetation two possible causes for this disparity related to the fluvial processes that furnish most pollen to fiords are 1 fluvial reworking of older sediment that contains abundantbetula and filicales and 2 greater resistance of these taxa to corrosion and degradation during fluvial transport the pollen stratigraphy of five piston cores from fiords contains two types of pollen assemblages in the lower portions of the cores exotic pollen types and pre quaternary palynomorphs are abundant the upper portions of the cores contain an assemblage roughly representative of the present vegetation in which cyperaceae and gramineae are abundant and exotic and pre quaternary types are reduced or absent the lower assemblage was deposited during the late glacial deglacial transition and deglaciation ca 12 000 to 6000 b p when eastern baffin island had little vegetation cover and long distance transport and reworking were virtually the only pollen sources a feature of several cores is a major peak in dinoflagellates about 5000 b p this event may be related to the postglacial marine climatic optimum in the eastern canadian arctic between 5000 and 3000 b p

exotic pollen as an indicator of variable atmospheric circulation over the labrador sea region during the mid to late holocene variability in the abundance of exotic non native pollen in sediment cores has long been considered as a potential proxy for changing atmospheric circulation but the difficulty of gaining sufficient total exotic pollen and the incomplete under standing of atmospheric pollen transport patterns has hindered its application in light of recent advances in the study of pollen transport we present an exotic pollen record from two fjord sediment cores taken from the west placentia bay newfoundland and east narsaq sund greenland labrador sea as a basis for studying variations in regional atmospheric circulation the two cores cover the last ca 5500 years and indicate a shift in dominant spring summer air masses at ca 2000 southern greenland and 3000 cal a bp newfoundland transporting reduced concentrations of pollen from southerly and south westerly vegetation zones this may suggest a shift away from more dominantly zonal atmospheric circulation a feature of positive north atlantic oscillation years to more frequent meridional circulation these results support sea ice sea surface temperature proxy reconstructions from newfoundland investigated as part of the same project which also suggest increased winter atmospheric circulation during the early part of the time period studied in this region more positive north atlantic oscillation years and therefore more zonal atmospheric circulation are associated with increased atmospheric circulation in both the winter and the summer seasons copyright 2011 john wiley sons ltd