reconstructing biomes from palaeoecological data a general method and its application to european pollen data at 0 and 6 ka biome models allow the results of experiments with atmospheric general circulation models to be translated into global maps of potential natural vegetation the use of biome models as a diagnostic tool for palaeoclimate simulations can yield maps that are directly comparable with palaeoecological pollen and plant macrofossil records provided these records are biomized i e assigned to biomes in a consistent way this article describes a method for the objective biomization of pollen samples based on fuzzy logic pollen types taxa are assigned to one or more plant functional types pfts then affinity scores are calculated for each biome in turn based on its list of characteristic pfts the pollen sample is assigned to the biome to which it has the highest affinity subject to a tie breaking rule modern pollen data from surface samples reflecting present vegetation across europe are used to validate the method pollen data from dated sediment cores are then used to reconstruct european vegetation patterns for 6 ka the reconstruction shows systematic differences from present that are consistent with previous interpretations the method has proved robust with respect to human impacts on vegetation and provides a rational way to interpret combinations of pollen types that do not have present day analogs the method demands minimal prior information and is therefore equally suitable for use in other regions with richer floras and or lower densities of available modern and fossil pollen samples than europe

methodology of the last climatic cycle reconstruction in france from pollen data abstract a numerical method has been devised to reconstruct the climate of the last climatic cycle from pollen data reliable annual reconstructions have been published recently for the two french long sequences of la grande pile and les echets covering the last 140 millennia this paper gives more details on the method used it proposes new reconstructions based on an extended modern pollen data base these reconstructions are consistent with the previous ones especially detailed information is obtained on the seasonal characteristics of climate computations of gcm on the climate variations from 125 kyr to 115 kyr b p are confirmed for western europe the insolation variations have induced at that time a decrease of seasonality accompanied by an increased cyclonic activity in winter this has been the beginning of the first ice growth after the last interglacial other glacier growth phases are detected at the end of substage 5c and particularly at the end of substage 5a

theory of quantitative reconstruction of vegetation i pollen from large sites reveals regional vegetation composition quantitative reconstruction of past vegetation is one of the primary goals in quaternary palynology and palaeoecology but still remains difficult this paper proposes a model reveals that estimates regional vegetation composition using pollen from large lakes that have small site to site variations of pollen assemblages even if vegetation is highly heterogeneous once these data have been used to quantify regional vegetation composition within 104 105 km2 background pollen one of the parameters crucial for vegetation reconstruction can be estimated for smaller sized sites and incorporated into the landscape reconstruction algorithm lra a multistep framework for quantitative reconstruction of vegetation in smaller areas 104 ha simulations using the pollscape modelling show that reveals can provide accurate estimates of regional vegetation composition in various landscapes and under different atmospheric conditions if pollen assemblages from lakes that are much smaller than large lakes a

cyclone and bioturbation effects on sediments from coral reef lagoons abstract despite the severity of tropical cyclone winifred which crossed the great barrier reef on 1 february 1986 there were little long term effects on lagoon surface sediments from reefs in its path short term effects were apparent only at one particularly exposed area these were an increase in proportion of the coarse fraction the establishment of sand ripples and the destruction of the mounds produced by callianassid shrimps normally the dominant topographic feature within six weeks this area was indistinguishable from a typical reef lagoon this is probably the result of sediment reworking by callianassid shrimp involving selective burial of the coarse fragments and transport to the surface of finer particles sediment turnover rates by callianassids are commensurate with change to the sediment within the relatively short period observed the sediment fauna responded quickly to the changes in sediment type immediately after the cyclone the disturbed area supported a fauna typical of the coarse sediments on the shallow reef flat as the sediment reverted to a more normal type so the fauna changed back to that typical of a reef lagoon

late quaternary variations in tree cover at the northern forest tundra ecotone 1 accurate land cover reconstructions are essential to understanding the past and present biogeochemical and biogeophysical interactions between the land surface and atmosphere and the impacts of these interactions on climate here we quantitatively reconstruct late quaternary shifts in woody cover across the northern hemisphere forest tundra ecotone based on a synthesis of northern hemisphere pollen records and contemporary observations of woody cover from the advanced very high resolution radiometer sensor our reconstructions document the expansion of northern hemisphere forests following deglaciation and reveal significant hemispheric asymmetries in the holocene position steepness and history of the forest tundra ecotone in western canada for example forest expansion and infilling continued through the holocene while in much of northern asia forests reached their maximal expansion during the early holocene then retreated the woody cover reconstructions are generally consistent with macrofossil based reconstructions of northern tree line dynamics and complement them by extending study of the northern forest tundra ecotone from the tree line limit well mapped by macrofossils to the entire ecotone using the lund potsdam jena dynamic vegetation model we estimate that changes in northern forest density resulted in at least a 47 7 gt c increase in aboveground carbon sequestration between 21 and 9 ka a 13 9 gt c increase between 9 and 6 ka and a 3 5 gt c loss of aboveground carbon from northern forests after 6 ka this trajectory is consistent with atmospheric carbon isotopic measurements for the holocene which suggest carbon uptake by the terrestrial biosphere until 6 ka and small carbon releases from the terrestrial biosphere afterward

holocene vegetation and climate of the alashan plateau nw china reconstructed from pollen data a set of 55 recent pollen spectra from the alashan plateau and the qilian mountains qilianshan northwestern china has been analyzed the established relationships between the pollen spectra and modern vegetation and precipitation patterns of the studied area have been applied to 65 fossil pollen spectra from a 825 cm long sediment record collected in the topographic depression formerly occupied by eastern juyan palaeolake 41 89 n 101 85 e 892 m a s l several qualitative approaches e g indicator plant species artemisia chenopodiaceae and ephedra fragilis type s l ephedra distachya type pollen ratios and quantitative methods of vegetation and climate reconstruction have been tested with the surface pollen and then applied to the eastern juyan pollen record fossil pollen data reveal pronounced environmental changes in the studied area of the alashan plateau between ca 10 700 and 1700 cal yr b p desert taxa as chenopodiaceae nitraria calligonum reaumuria were abundant in the vegetation cover around the study site through the whole record pollen spectra dated to ca 10 700 5400 cal yr b p are characterised by highest values of chenopodiaceae e fragilis type and other desert indicating taxa suggesting rather dry climate most favourable conditions are reconstructed between 5400 and 3900 cal year b p on the basis of relative increase in abundance of artemisia pollen a return to dry conditions occurred at about 3900 cal yr b p the lake finally desiccated after 1700 cal yr b p reconstructed dry climate oscillations between 5900 and 5400 and 3100 cal yr b p correlate well with similar events found in the published records from northern and western china and central mongolia however eastern juyan record does not show the early holocene humidity maximum as suggested by the sedimentary data from monsoon influenced areas of china

mechanical behavior of groundwater seepage in karst collapse pillars abstract groundwater inrush has an impartible relationship with geological structures such as karst collapse pillars kcps which are widely distributed in north china in order to study the mechanism of groundwater inrush from coal seam floor the variable mass dynamics and nonlinear dynamics were introduced a mechanical model plug model is established to describe the behavior of water seepage flow in coal seam floor containing kcp the study shows that 1 if the mass of the kcp keeps steady the water seepage velocity in the kcp and the surrounding rocks will reach a constant value soon 2 if the mass of the kcp and the surrounding rocks increases by grouting etc the seepage velocity in the kcp and the surrounding rocks will reach its minimum value gradually and 3 if the mass of the kcp and the surrounding rocks decreases by scouring the flow velocity in the kcp and the surrounding rocks shows a monotone increase the water flow may change into pipe flow especially when a large number of the mass of the kcp and the surrounding rocks enters into goaf road which may lead to instable flow and cause groundwater inrush

insolation values for the climate of the last 10 million years new values for the astronomical parameters of the earth s orbit and rotation eccentricity obliquity and precession are proposed for paleoclimatic research related to the late miocene the pliocene and the quaternary they have been obtained from a numerical solution of the lagrangian system of the planetary point masses and from an analytical solution of the poisson equations of the earth moon system the analytical expansion allows the direct determination of the main frequencies with their phase and amplitude numerical and analytical comparisons with the former astronomical solution ber78 are performed so that the accuracy and the interval of time over which the new solution is valid can be estimated the corresponding insolation values have also been computed this analysis leads to the conclusion that the new values are expected to be reliable over the last 5 ma in the time domain and at least over the last 10 ma in the frequency domain

the distribution of late quaternary woody taxa in northern eurasia evidence from a new macrofossil database we present a database of late quaternary plant macrofossil records for northern eurasia from 23 to 180 e and 46 to 76 n comprising 281 localities over 2300 samples and over 13 000 individual records samples are individually radiocarbon dated or are assigned ages via age models fitted to sequences of calibrated radiocarbon dates within a section tree species characteristic of modern northern forests e g picea larix tree betula are recorded at least intermittently from prior to the last glacial maximum lgm through the lgm and lateglacial to the holocene and some records locate trees close to the limits of the scandinavian ice sheet supporting the hypothesis that some taxa persisted in northern refugia during the last glacial cycle northern trees show differing spatio temporal patterns across siberia deciduous trees were widespread in the lateglacial with individuals occurring across much of their contemporary ranges while evergreen conifers expanded northwards to their range limits in the holocene

epiphyte communities on thalassia testudinum from grand cayman british west indies their composition structure and contribution to lagoonal sediments abstract thalassia testudinum the most common seagrass found in lagoons around grand cayman influences sedimentation by baffling currents binding sediment on the seafloor and providing substrates for a diverse epiphytic biota about 85 of the epiphytic biota is formed of at least 3 species of coralline algae 72 species of foraminifera and 61 species of diatoms the rest of the biota is formed of sponges gastropods ostracods coccoliths dinoflagellates brown algae and worms the epiphytes are organized in three communities that are part of an organized tripartite community succession the basal diatom community is overlain by the coralline algae community which is then overlain by a community composed of a variety of taxa the coralline algae community which is the most extensive typically covers 75 of the leaf s surface potentially the skeletons of these epiphytes can make a significant contribution to the fine grained sediment budget of these lagoons surprisingly only a few of the epiphytes were found in the lagoonal sediment it appears therefore that the epiphytes are lost through skeletal dissolution or transported out of the lagoon following storms irrespective of the cause the epiphytes do not form a significant part of the lagoon sediment in grand cayman

holocene vegetation change at treeline north of yellowknife northwest territories canada abstract two radiocarbon dated cores from small lakes located approximately 25 km north of the mapped boundary between forest tundra and tundra provide records of postglacial vegetation change at the treeline near yellowknife nwt canada basal radiocarbon dates of 6180 and 7470 yr b p were obtained from the cores the fossil pollen evidence suggests that the initial vegetation was betula tundra with a peatland component alnus became an important constituent of the pollen assemblages between 6900 and 5500 yr b p both lakes record sharp increases in picea cf mariana pollen at approximately 5000 yr b p suggesting the establishment of forest tundra by 3500 yr b p picea mariana forest tundra had withdrawn the proportion of organic to inorganic sediment in the cores was at a maximum between 5000 and 3500 yr b p tundra has dominated the region since 3500 yr b p in northwestern canada the maximum northward advance of treeline occurred between 9000 and 5000 yr b p the asynchrony in treeline advance in central and northwestern canada may reflect that glacial ice persisted in the interior nwt longer than previously believed alternatively the asynchronous history of the treeline may be a result of the geometric properties of the long wave westerly disturbance that is manifest in the median summer position of the arctic front and ultimately controls the geographic location of the treeline

satellite and pollen based quantitative woody cover reconstructions for northern asia verification and application to late quaternary pollen data abstract accurate reconstruction of late quaternary vegetation cover is necessary for better understanding of past vegetation dynamics the role of vegetation feedbacks in glacial interglacial climate variations and for validating vegetation and climate models in this paper over 1700 surface pollen spectra from the former soviet union mongolia northern china and northern japan together with data from the advanced very high resolution radiometer avhrr were used to calibrate modern analogue method for quantitatively reconstructing past woody cover from fossil pollen data the avhrr based estimates of woody cover percentages within a 21 21 km window around pollen sampling sites were attributed to the respective modern pollen spectra reconstructions of modern woody cover using the pollen data and best modern analogues bma method matched well to the original avhrr based estimates for both total woody cover r 2 0 77 and its fractions including broad leaved r 2 0 66 needle leaved r 2 0 79 deciduous r 2 0 60 and evergreen r 2 0 76 woody cover discrepancies in the pollen avhrr cross validation may be caused by long distance transport of arboreal pollen patchy forest distributions underrepresentation of larix and populus in pollen records and errors in the avhrr classification the generally strong correlations encourage application of the modern analogue approach for reconstructing late quaternary variations in vegetation cover from northern asian fossil pollen records at the last glacial maximum lgm 21 000 cal yr bp areas presently occupied by boreal forest were much more open suggesting a reduction in total woody cover to below 20 at most modern forest sites pollen records from northern and central siberia suggest a rather quick spread of tree and shrub vegetation after 15 000 cal yr bp presumably in response to increased summer insolation woody cover histories are spatially variable in the modern forest steppe where tree growth is largely controlled by the ratio of annual actual over potential evapotranspiration which serves as an index of moisture availability in northwestern mongolia woody cover percentages decreased between 9000 and 5000 cal yr bp and again between 2000 and 1000 cal yr bp and may be linked to shifts in intensity of the pacific monsoon in contrast pollen data from the kazakhstan forest steppe where atmospheric precipitation is associated with the atlantic westerly flow suggest that woody cover density reached modern levels only during the last millennium

the importance of symbiont bearing benthic foraminifera for west pacific carbonate beach environments abstract in the tropical central and west pacific as well as in the east indian ocean symbiont bearing benthic foraminifera often are the main producers of calcium carbonate grains deposited at beaches the proportion of foraminiferal tests in medium sized to coarse sand grains may range from 20 to 95 this depends on two factors productivity and transport because foraminifers do not live on or in the sandy bottom near the beaches but prefer firm substrate in high energy environments close to the front of coral reefs foraminiferal tests are produced in extreme numbers on the reef crest of sesoko island okinawa japan 0 6 kg m 2 year 1 which is covered by macroalgae or in the transition zone between the crest and the reef moat 1 3 kg m 2 year 1 empty tests released by reproduction or death are entrained at the reef crest by waves and transported by currents this transport depends on the direction and intensity of currents connecting the habitat reef crest and transition to moat with the deposition area central moat lagoon beach habitat destruction and or the interruption or diversion of water flow hinders the accumulation of foraminiferal tests at the beach where deepening the moat intensifies beach parallel currents supply to and deposition at the beach are reduced while the remaining sand is eroded by tropical cyclones understanding the ecology especially population dynamics of larger foraminifera in combination with factors influencing the transport of empty tests is essential to preserve the balance between deposition and removal of sand at carbonate beaches in the west pacific and east indian ocean

estimating carbon accumulation rates of undrained mires in finland application to boreal and subarctic regions equations based on empirical relationships of peat physical properties were used to estimate the average long term apparent rate of carbon accumulation lorca in finnish mire vegetation regions the results were generalized to the boreal and subarctic regions analyses of 1302 dated peat cores were used to infer carbon accumulation for each mire vegetation region of finland the area weighted lorca for finnish undrained mire areas was 18 5 g m 2 yr 1 and the total carbon sink 0 79 tg yr 1 1 tg 1012g the total carbon pool of finnish undrained mires was estimated as 2257 tg the aapa mire region included 80 of the total net accumulation rate of carbon and 85 of the total carbon reservoirs of finnish undrained mires lorca was signi cantly higher in the raised bog region 26 1 g m 2 yr 1 compared with the aapa mire region 17 3 g m 2 yr 1 and bogs generally had a higher lorca 20 8 g m 2 yr 1 than fens 16 9 g m 2 yr 1 the total c sink for boreal and subarctic mires was estimated at 66 tg yr 1 whi

mg ca and sr ca as novel geochemical proxies for understanding sediment transport processes within coral reefs sediment transport is a key driver of reef zonation and biodiversity where an understanding of sediment dynamics gives insights into past reef processes and allows the prediction of geomorphic responses to changing environmental conditions however modal conditions within the back reef seldom promote sediment transport hence direct observation is inherently difficult large benthic foraminifera lbf have previously been employed as tracers to infer sediment transport pathways on coral reefs as their habitat is largely restricted to the algal flat and post mortem their calcium carbonate test is susceptible to sediment transport forces into the back reef foraminiferal test abundance and post depositional test alteration have been used as proxies for sediment transport although the resolution of these measures becomes limited by low test abundance and the lack of variation within test alteration here we propose the novel use of elemental ratios as a proxy for sediment transport two species baculogypsina sphaerulata and calcarina capricornia were analysed using a taphonomic index within one tree and lady musgrave reefs great barrier reef australia inductively coupled plasma atomic emission spectrometry icp aes was used to determine mg ca and sr ca and these ratios were compared with taphonomic data decreases in test mg ca accompany increases in sr ca in specimens from algal flat to lagoonal samples in both species mirroring trends indicated by taphonomic values therefore indicating a relationship with test alteration to delineate mechanisms driving changes in elemental ratios back scattered electron bse images elemental mapping and in situ quantitative spot analyses by electron microprobe microanalysis epma using wavelength dispersive x ray spectrometers wds were performed on un altered algal flat and heavily abraded tests for both species epma analyses reveal heterogeneity in mg ca between spines and the test wall implying the loss of appendages results in a decrease in mg ca bse imaging and wds elemental mapping provided evidence for cementation facilitated by microbial boring as the primary cause of increasing sr ca these novel proxies hold advantages over taphonomic measures and further provide a rapid method to infer sediment transport pathways within back reef environments

micropaleontology of the 2013 typhoon haiyan overwash sediments from the leyte gulf philippines abstract coastal geologic records allow for the assessment of long term patterns of tropical cyclone variability however the accuracy of geologic reconstructions of tropical cyclones is limited by the lack of modern analogues we describe the microfossil foraminifera and testate amoebae assemblages contained within overwash sediments deposited by typhoon haiyan when it made landfall on the islands of leyte and samar in the philippines on 7 november 2013 as a category 5 super typhoon the overwash sediments were transported up to 1 7 km inland at four study sites the sediments consisted of light brown medium sand in a layer

studies on settling traction and entrainment of larger benthic foraminiferal tests implications for accumulation in shallow marine sediments settling and traction velocities were measured on optimally preserved tests of larger foraminifera using a settling tube and flume tank within larger foraminifera with porcelaneous tests the peneroplids peneroplis antillarum p planatus p pertusus and dendritina cf d zhengae are distinguished by low test densities ca 1 2 that do not change with growth buoyancy is high because of low reynolds numbers and increases in large individuals because of the allometric change of test shape the fusiform alveolinella quoyi with test densities ca 1 6 is characterized by high reynolds numbers inducing the weakest buoyancy within porcelaneous larger foraminifera the highest buoyancy was recorded for the three soritids parasorites orbitolitoides sorites orbiculus and amphisorus hemprichii because of their low test densities ca 1 25 and the extremely flat biconcave plate like shape flat tests however reduce traction and entrainment from smooth surfaces within hyaline larger foraminiferat the amphisteginids show thick lenticular amphistegina lobifera a radiata to thin lenticular tests a bicirculata a papillosa influencing buoyancy here high test densities ca 1 8 decrease with growth in a lobifera a lessonii and a bicirculata and remain constant in a radiata and a papillosa minimum velocities required for entrainment are lower for thick lenticular tests and higher for thin lenticular tests test densities remain constant with growth in the calcarinid baculogypsina sphaerulata 1 78 and decrease slightly in calcarina gaudichaudii and neorotalia calcar starting at 1 85 all living under extreme hydrodynamic conditions density decreases the most in baculogypsinoides spinosus starting at 1 8 resulting in higher buoyancy through low reynolds numbers traction is promoted in spherical tests of baculogypsina and baculogypsinoides within nummulitids the thick lenticular palaeonummulites venosus test density decreasing with size starting at 1 78 is less buoyant expressed in high reynolds numbers but easily entrained thick lenticular juveniles and extremely flat adults distinguish operculinella cumingii heterostegina depressa and the giant cycloclypeus carpenteri test densities increase during growth starting from ca 1 6 and attaining a maximum of 1 8 buoyancy is low in small tests and high in large tests while entrainment velocities are reduced as the tests flatten high buoyancy is also a characteristic of the entirely flat tests in operculina ammonoides from deeper regions and planostegina operculinoides which is expressed in the lowest reynolds numbers within larger foraminifera

soil feedback drives the mid holocene north african monsoon northward in fully coupled ccsm2 simulations with a dynamic vegetation model we explore climate vegetation interactions in mid holocene north africa with a suite of community climate system model ccsm2 simulations the ccsm includes synchronously coupled atmosphere ocean sea ice land and vegetation models the ccsm s present day precipitation for north africa compares well with simulations of other models and observations mid holocene data reveal a wetter and greener sahara compared to the present the ccsm exhibits a greater closer to the expected precipitation increase than other models and in response grasses advance from 18 75 to 22 5 n in much of north africa precipitation is enhanced locally by the northward advance of grasses but suppressed regionally mainly due to an insufficient albedo decrease with the expansion of vegetation prior studies have always lowered the surface albedo with the expansion of vegetation in north africa in the ccsm s mid holocene simulations the albedo decreases more because wetter soils are simulated darker than drier soils than due to expanding vegetation these results isolate albedo as the key ingredient in obtaining a positive precipitation vegetation feedback in north africa two additional simulations support this conclusion in the first simulation the desert s sandy soil textures are changed to loam to represent increased organic matter soil water retention and grass cover increase albedo decreases somewhat precipitation responds with a small yet widespread increase in the second simulation a darker soil color is prescribed for this region now the monsoon advances north about 4 these results illustrate a north african monsoon highly sensitive to changes in surface albedo and less sensitive to changes in evapotranspiration

depth transport functions and erosion deposition diagrams as indicators of slope inclination and time averaged traction forces applications in tropical reef environments abstract the trigonometric relationship between slope inclination the horizontallyacting time averaged traction force and the vertical depth of transport allowsthe estimation of one factor when both others are known depth transportfunctions can be deduced by comparing the depth distributions of livingorganisms and their skeletal remains and this paper simpli es this comparisonusing foraminifera in which a single test represents an individual differencesin distribution parameters between living individuals and empty tests allowdepth transport functions to be determined these functions differ betweenspecies at a single transect according to the varying buoyancies of the tests within a single species differences in depth transport functions betweenlocations are based on either slope inclination or traction intensities afterestablishing a mean depth transport function by averaging species characteristic functions the time averaged traction force acting on thestudied transect can be calculated transport intensities are also estimatedusing an erosion deposition diagram that combines the relative frequencydistributions of living individuals and empty tests the proportion of eroded parautochthonous and allochthonous tests mirrors the in uence of bothslope inclination and traction force for the deposition of empty tests to test themodel six species of symbiont bearing benthic foraminifers were investigatedat two transects in front of a nw paci c coral reef one transect is distinguishedby a strong slope attening below the steep reef slope 30 m whereas furthersteepening characterizes the equivalent part in the other transect thesedifferences are mirrored in the depth transport functions as well as in theerosion deposition diagrams of all species the time averaged traction forcesdiffer in intensities between transects because of the position of the reef frontwith respect to the predominant wind direction however the form of thefunctions is identical and distinguished by an increase from the surface to 35 mdepth followed by a decrease down to 105 m this can be explained bysuccessive onshore and offshore forces acting on the shallow slope such as thetropical cyclones that cross the region every summer keywords carbonate sands coral reef slopes foraminifera sediment trans port traction force tropical cyclones introductionsediment transport on the slopes and forereefareas greatly in uences the topography of coralreefs as carbonate produced by reef buildingorganisms is rapidly reduced to sediment especially at the reef front e g hubbard et al 1990 the overwhelming of reef growth bysedimentology 2001 48 1025 1046

palynological and avhrr observations of modern vegetational gradients in eastern north america both fossil pollen records and satellite based instruments are remote sensors of earth s vegetation with complementary properties satellites supply spatially continuous and highly resolved images for the past several decades whereas pollen records include local and regional signals of vegetation composition spanning millennia together pollen and satellite based observations measure vegetation change across a broad range of temporal scales here we compare pollen percentages of needleleaved and broadleaved plant taxa to avhrr estimates of percent tree cover for two regions in eastern north america with well defined physiognomic gradients the linear fit between the pollen percentages and percent tree cover is strongest for search window half widths of 25 75 km and unweighted or inverse distance weightings consistent with previous taxon based studies of regional pollen source area and transport variance not explained by the linear model arises primarily from differential properties of the avhrr and

she analysis for biozone identification among foraminiferal sediment assemblages on reefs and in associated sediment around st kitts eastern caribbean sea and its environmental significance abstract sixteen nearshore 1 m water depth sediment samples termed sample set 1 were collected from the eastern and south western coasts of the south east peninsula sep of st kitts twelve samples termed sample set 2 were taken from nearby fringing 6 17 m and offshore 18 25 m reefs the sample sets were analysed separately using she analysis for biozone identification shebi and diversities and complementarity shebi is a statistical technique that determines abundance biozones abs using the entire vector of species abundances in samples species richness s the information function h and the equitability index e alpha diversity expresses the diversity within an ab while diversity quantifies diversity changes between adjacent abs complementarity assesses the permeability of ab boundaries shebi divided sample set 1 into five abs but did not distinguish separate bays beta diversities reflected the highest and lowest diversities at mosquito bay and south friar s beach frigate bay respectively complementarity was highest between two abs in south friar s bay indicating a close relationship between shoreline sediment and material marginally farther offshore it was lowest between whitehouse and south friar s bays the assemblages along this transect were rich in discorbis rosea for sample set 2 samples were accumulated for shebi by depth shebi distinguished four abs three on the fringing reefs characterised by differing percentages of asterigerina carinata archaias angulatus and amphistegina gibbosa comparison between sample sets 1 and 2 indicates that during storms sediment moves shoreward from the fringing reefs foraminifera show that there is less movement of sediment 63 m from the shoreline sample set 1 to the fringing and deeper reefs

carbonate sediment transport pathways based on foraminifera case study from frank sound grand cayman british west indies foraminifera can be used to determine the source s of carbonate sediment and the directions of sediment transport in shallow coastal lagoons such as frank sound on the south central coast of grand cayman these determinations based on the distribution of foraminiferal assemblages and tracer species numerically abundant species that live in known physiographic units and or ecological conditions show that the lagoonal sediments are a mixture of grains that originated in the lagoon and forereef the variable proportions of these foraminifera throughout the lagoon reflects the dynamic processes that control lagoonal sedimentation amphistegina gibbosa discorbis rosea and asterigerina carinata lived in the forereef environment the fact that these tracer species are found throughout frank sound and in the beach sands shows that they were transported across the reef crest and the lagoon abrasion resistant archaias angulatus a tracer species indicative of a lagoonal setting forms up to 50 of foraminiferal assemblages found in the lagoonal sediments preferential winnowing of small tests from these populations indicates sorting under high energy conditions the vertical distribution of the forereef and lagoonal foraminifera in the sediment blanket that covers the floor of frank sound indicates that these processes are temporally persistent transportation of forereef foraminifera into and around the lagoon and sorting of the lagoonal foraminifera cannot take place under normal conditions when the tranquil lagoon is characterized by weak currents storms and or hurricanes however generate short lived high energy events that can move and sort the sediment and foraminifera at the height of a storm water and sediment are moved over the reef and then piled and held onshore by the onshore winds and the constant flow of water over the reef and across the lagoon these currents can mix some of the lagoonal and forereef sediments as a storm wanes however the piled water flows offshore via strong rip currents that pass into the ocean through the channels which transect the reef these currents winnow and or strip sediment from the lagoon and may transport lagoonal sediments into the forereef area as a result residual lagoonal sediment is commonly characterized by larger and abrasion resistant foraminifera

sediment production and dispersal on foraminifera dominated early tertiary ramps the eocene el garia formation tunisia larger benthic foraminifera nummulites are common within eocene circumtethyan limestones despite their importance as sediment producers contradictions in the literature constrain current understanding about the location of the nummulites factory the el garia fm was deposited on a ramp with localized palaeohighs and whilst some authors suggested that the locus of nummulites production was in shallow water across the palaeohighs others concluded that production was significantly reduced over these palaeohighs and concentrated in the surrounding deeper 30 60 m water there are also marked dissimilarities between recent models in terms of the continuity correlation and resolution of depositional sequences to assess these models we integrate studies of the architecture and geometry of the el garia fm with detailed taphonomic biometric biofabric and palaeoecological characterization of nummulites tests we conclude that the highest rates of sediment production occurred in euphotic water over the palaeohighs and in nearshore environments nummulites on the palaeohighs were transported into the surrounding deeper water by oceanic and storm currents that swept the platform top producing a nummulitic sediment package that thickened and became increasingly fine grained and fragmented into outer ramp environments this transport exerted a major control on development of the ramp like geometries often seen at outcrop our findings question the validity of a recent sequence stratigraphic model that identifies decimetre scale milankovitch cycles even in largely allochthonous bio retextured mid outer ramp sediments our findings also suggest that the thin packages of el garia fm on the palaeohighs which have previously been interpreted as condensed sections that can be correlated with thicker more distal accumulations actually represent remnants of the sediment that was produced on the highs and exported into the basin

mapped plant macrofossil and pollen records of late quaternary vegetation change in eastern north america abstract macrofossil presence absence maps and isopoll maps in 3000 year intervals show how ranges and abundance maxima for 12 eastern north american tree and shrub taxa picea p glauca p mariana larix laricina abies balsamea tsuga canadensis pinus strobus p resinosa p banksiana betula papyrifera b alleghaniensis b series humiles have changed from the last glacial maximum to the present the macrofossil maps corroborate patterns shown by the isopoll maps and provide spatial detail and taxonomic resolution the macrofossils confirm the inference from pollen data that unglaciated southeastern north america was cooler during the last glacial maximum 18 and 15 ka than simulated by the cohmap experiments with the ncar ccm0 general circulation model the geographic distribution of macrofossil occurrences during the late glacial 12 and 9 ka indicate that migration lag of boreal species did not occur at regional to subcontinental scales and that pollen assemblages lacking modern analogs resulted from climate gradients lacking modern analogs early holocene 9 and 6 ka macrofossil maps show rapid northward expansion of tree species ranges into deglaciated regions the data also show modest contractions of northern range limits of temperate species and expansions of southern range limits of boreal species in response to cooling trends during the late holocene 3 and 0 ka comparison of modern macrofossil maps of nine of these taxa with corresponding range maps confirm that the macrofossils record the geographic ranges accurately comparison of the modern macrofossil maps with maps of tree growing stock volume shows that for some taxa abies tsuga macrofossil occurrences were most frequent in regions of maximum tree abundance comparison of modern isopoll maps with the modern range and growing stock volume maps indicate that in contrast to the macrofossil data the pollen data provide poorer resolution of range limits for most taxa but better indications of abundance maxima and minima within the ranges

sediment transport trends from a tropical pacific lagoon as indicated by homotrema rubra taphonomy wallis island polynesia the assessment of sediment transport pathways in carbonate settings is complicated by ecologically sourced sediment tracers such as foraminifera have previously been used in these settings to describe the movement of coastal sediments on spatial and temporal scales where traditional grain size methods have limited use the present study builds on the foraminifera based tracer method by using homotrema rubra a foraminifer with an attached life habit i e defined provenance in the reef to document modern sediment transport trends at wallis island a tropical pacific lagoon at wallis island homotrema taphonomic results discriminated amongst modern reef lagoon and island beach samples reef samples contained high concentrations of fragments that were large 250 m and exceptionally to well preserved e g intact chambers red color angularity in general concentrations and degree of taphonomic alteration decreased with distance landward from the reef lagoon samples were characterized by lower concentrations of homotrema that were smaller in size and less preserved e g pink in color no chamber structure rounding of edges at the greatest distance from the reef island beach samples contained the lowest concentrations of homotrema fragments that were small well rounded and bleached in this regard homotrema taphonomy is a useful indicator of the direction and forcing of sediment transport and will therefore be useful in detecting overwash deposits in tropical settings where distinguishing event deposits from surrounding sediment is problematic

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

a detrital sediment budget of a maldivian reef platform abstract sediment dynamics are an important control on the morphology and development of reef systems by actively removing and redistributing excess detrital sediment this study presents quantitative data from direct point measurements of sediment transport on the platform surface and fore reef slope of vabbinfaru reef north male atoll maldives a suite of sediment traps were used to construct actual rates of platform sediment fluxes and off reef export over different spatial and temporal seasonal scales to establish key sediment transport pathways findings showed that high sediment fluxes occur on vabbinfaru platform in the absence of major storm activity up to 1905 g m 1 d 1 with 95 of annual transport occurring during the southwest monsoon as a result of increased wave energy climate driven changes in the platform process regime caused a reversal of net sediment transport pathways between each monsoon season off reef export rates were high reaching a maximum of 12 58 kg m 1 y 1 for gravel and 407 g m 1 d 1 for sand sized sediment an estimated 127 120 kg is exported from the platform annually equating to a significant loss from the reef sediment budget and contributing to the long term geomorphic development of the fore reef slope and atoll basin detrital sediment reservoirs on vabbinfaru are not purely depositional carbonate sinks but rather temporary stores that are important in the transfer of sediment between reef zones

lagoon shelf sediment exchange by storms evidence from foraminiferal assemblages east coast of grand cayman british west indies abstract the abundance and size distribution of ecologically diagnostic foraminiferal species are ideal tracers of sediment transportation and storm processes on the windward shelf of grand cayman during storm peak sediment in the lagoon and fore reef is suspended by large storm waves sediments of sand size and finer including forereef foraminifera species are moved shoreward by wind driven currents and deposited in a blanket behind the reef the fore reef foraminiferal assemblage is winnowed and the mean and median sizes of amphistegina gibbosa progressively decrease from the shelf edge into the inner lagoon as the storm wanes water piled in the lagoon drains via channels and sediment is transported offshore consequently lagoonal sediment that includes lagoonal foraminiferal t sts is carried out of the lagoon and deposited on the fore reef terrace and down the shelf escarpment this process produces winnowed lagoonal sediments because suspended fine sediments are preferentially transported during the long inter storm periods tranquil conditions are once again established and sediment exchange between the lagoon and on the fore reef terrace ceases during this time lagoonal organisms once again colonize the lagoon and bioturbation causes mixing of surface and subsurface sediments

sedimentology and budget of a recent carbonate mound florida keys the sedimentology of a recent carbonate mound is investigated to further our understanding of mound building communities surface and subsurface mound sediments and the overall sediment budget of mounds nine sedimentary facies of the surface of tavernier mound florida keys are described these sediments are composed of neogoniolithon halimeda porites mollusc and foraminiferal grains and lime mud muds rich in aragonite and high magnesian calcite show little mineralogical variation over the mound surface geochemical evidence suggests that the mud is mainly formed from breakdown of codiacean algae and thalassia blade epibionts production rates of the facies are established from in situ growth rate experiments and standing crop surveys annual calcium carbonate production is c 500gm 2 intermediate between reef and other bay and lagoonal environment production rates in the caribbean the internal structure of the mound studied from piston cores and sediment probes indicates that seven facies can be identified five of these can be related to the present day facies and occur in the upper part of the mound gravel mound stage the remaining two facies characterized by molluscs and aragonite rich muds occur in the lower part of the mound mud mound stage and are most similar to facies from typical florida bay mud mounds mangrove peats within the mound indicate former intertidal areas and c14 dates from these peats provide a time framework for mound sedimentation the mound appears to have formed because of an initial valley in the pleistocene surface which accumulated mud in a shallow embayment during the holocene transgression a sediment budget for the mound is presented which compares production rates from present day facies with subsurface sediment masses during the mud mound stage production rates were similar to accumulation rates and the mound was similar to the present day mounds of florida bay during the gravel mound stage 3400 yr bp present day conditions were more normal marine and the establishment of porites and neogoniolithon on the mound increased production rates 10 over accumulation rates this excess sediment is thought to be transported off the mound to the surrounding seabed models are proposed which divide carbonate mounds on the basis of internal versus external sediment supply comparisons are made with other recent and ancient mounds similarities exist between the roles of the biotic components of late palaeozoic mounds but major differences are found when structures and early diagenesis are compared

sphagnum peatland distribution in north america and eurasia during the past 21 000 years the distribution and abundance of sphagnum spores in north america and eurasia are mapped for the past 21 ka the present day distribution of abundant sphagnum spores corresponds closely to areas with peatland development with maximum sphagnum abundance between 630 and 1300 mm annual precipitation and between 2 and 6 c mean annual air temperature during the wisconsin glaciation there were apparently not large areas of peatland in north america except in alaska high sphagnum spore percentages were found in eastern north america during deglaciation major peatland development occurred in boreal north america after 9 ka and there was a southward movement of high sphagnum spore abundance after 5 ka in the western great lakes region major peatland development began after 9 ka in europe and asia on the basis of maps of the area supporting peatlands carbon accumulation in peatlands is estimated to be low prior to 11 ka increased slightly between 11 and 5 ka and greatly increased during the past 5 ka

ovummuridae calcareous microfossils from a late devonian ramp their distribution preservation potential and paleoecological significance enigmatic calcareous microfossils that belong to the ovummuridae munnecke servais and vachard 2000 are present in ten cores through the upper part of the escarpment formation and alexandra formation in the hay river area of the northwest territories canada these late devonian frasnian siliciclastic mixed carbonate siliciclastic and carbonate ramp deposits accumulated on the western margin of laurussia finding ovummurids in these deposits is significant because it provides the first formal documentation that these microorganisms existed in the devonian and confirms that the stratigraphic range of the family extends from the lower silurian to upper permian the microfossils which are of unknown biological affinity include minourella gotlandica previously known only from silurian strata ovummurus duoportius and minourella cameroni sp nov the preservation potential of these microfossils was markedly enhanced by thick cement overgrowths akin to the syntaxial overgrowths that are common on pal

middle eocene nummulites and their offshore re deposition a case study from the middle eocene of the venetian area northeastern italy abstract the middle eocene calcari nummulitici formation from northeastern italy venetian area represents a shallow marine carbonate ramp developed on the northern tethyan margin in the monti berici area its main components are larger foraminifera and coralline red algal communities that constitute thick carbonate sedimentary successions middle ramp and proximal outer ramp environments are recognized using component relationships biofacies and sedimentary features the middle ramp is characterized by larger flattened lenticular nummulites on palaeohighs between which rhodoliths formed larger nummulites palaeohighs containing nummulites millecaput nummulites crassus nummulites discorbinus and nummulites cf gizehensis developed more basin wards the following relatively quiet environments of basin wards of the palaeohighs represent areas of maximum carbonate production the transition between the distal middle and the proximal outer ramp settings is marked in the study area by a large erosional surface which is interpreted to have been formed as a result of an erosive channel body filled in by deposits re sedimented from shallower depths these off shore re sedimented channelized deposits ascribed to the shallow benthic zone sbz 15 lying on hemipelagic marls planktonic foraminiferal zone e9 p11 allow for a biostratigraphic correlation to the late lutetian the studied deposits represented by packstone to rudstones were displaced whilst still unlithified the lutetian bartonian regression along with the local tectonic activity promoted the production of a high amount of biogenic shallow water carbonates mainly produced in the mossano middle ramp settings these prograded towards the basinal areas with high sedimentation rate of carbonate deposits characterized by the larger nummulites rudstones such high amounts of sediment led to sediment instability which potentially could be mobilized either by return currents due to occasional major storms or by earthquakes induced by tectonic activity these will have led to the offshore re deposition of the nummulites sediments into deeper water setting via the observed channels since potential migration pathways are short such distal re sedimented channel filled material surrounded by hemipelagic marls is optimally placed for the formation of potential subsurface oil reservoirs

holocene lagoonal sedimentation at the latitudinal limits of reef growth lord howe island tasman sea abstract the southernmost limit to coral reef growth occurs on lord howe island 33 30 s 159 05 e where a discontinuous fringing reef flanks the western side of the island coring and radiocarbon dating indicate that carbonate sediments were first deposited within the lagoon around 6500 radiocarbon years bp coincident with sea level reaching close to its modern level high energy conditions dominated the reef with robust branching corals dominating the developing reef growth of the reef crest between 6000 and 5000 yr bp is inferred to have caused a reduction in the energy conditions within the lagoon resulting in mud deposition during this period sedimentation occurred at average rates of around 5 mm yr though locally up to 10 mm yr which infilled almost all the available accommodation space in the lagoon by 4000 yr bp most of the lagoon had accreted to a level very close to the modern lagoon floor having accumulated over 11 m of sediment in the northern part of the lagoon and possibly up to 30 m in the south sediments younger than 3000 yr bp form a thin veneer over these older units with the main deposition being confined to embayments the coastal plain and the infilling of blue hole depressions the reef and lagoon fringing lord howe island appear to have developed their present form primarily during a phase of luxuriant growth in the mid holocene

the temperature of europe during the holocene reconstructed from pollen data we present the first area average time series reconstructions of warmest month coldest month and mean annual surface air temperatures across europe during the last 12 000 years these series are based on quantitative pollen climate reconstructions from over 500 pollen sites assimilated using an innovative four dimensional gridding procedure this approach combines three dimensional spatial gridding with a fourth dimension represented by time allowing data from irregular time series to be focussed onto a regular time step we provide six regional reconstructed temperature time series as well as summary time series for the whole of europe the results suggest major spatial and seasonal differences in holocene temperature trends within a remarkably balanced regional and annual energy budget the traditional mid holocene thermal maximum is observed only over northern europe and principally during the summer this warming was balanced by a mid holocene cooling over southern europe whilst central europe occupied an intermediary position changes in annual mean temperatures for europe as a whole suggest an almost linear increase in thermal budget up to 7800 bp followed by stable conditions for the remainder of the holocene this early holocene warming and later equilibrium has been mainly modulated by increasing winter temperatures in the west which have continued to rise at a progressively decreasing rate up to the present day

nepartak typhoon influenced bottom sediments from the yangtze river estuary and adjacent east china sea foraminiferal evidence foraminiferal taphocoenose characteristics notably allochthonous tests in surface sediment samples from the yangtze river estuary and adjacent areas in the east china sea were examined during july 2016 and after typhoon nepartak february 2017 crossed this region a comparison of transport indices from five sample stations reveals that this typhoon significantly strengthened sediment transport although the transport in predominate direction twcnorth branch occurs all year moreover findings from a comprehensive impact of currents topography test size and shape as well as other abiotic factors show that transport occurs in the order from stronger to weaker south north path southeast northwest path nearshore northeast path along the south north path the twcnorth branch transports larger tests of taxa ammonia compressiuscula and cavarotalia annectens as bed load along the gentle seabed in a rolling or saltating process results from the southeast northwest path show smaller and bulging tests of the dominant species epistominella naraensis and bolivina robusta may be transported as suspension load along the steep submarine valley by the twcnorthwest branch on the nearshore northeast path only part of allochthonous tests ammonia beccarii vars was transported probably due to distance travelled and weakening of the typhoon furthermore we also infer the northeastern area as a sink zone that accumulates grains of allochthonous tests predominantly from the southern source zone and a selection of tests from littoral species originating from the nearshore source zone it is important to identify and independently count allochthonous test samples if a large number of these tests are recorded findings from this study provide a reference to identify and investigate typhoon modern effects in areas with complex currents and frequent strong physical dynamic events as well as their geological records

holocene carbon cycle dynamics 1 we are investigating the late holocene rise in co2 by performing four experiments with the climate carbon cycle model climber2 lpj apart from the deep sea sediments important carbon cycle processes considered are carbon uptake or release by the vegetation carbon uptake by peatlands and co2 release due to shallow water sedimentation of caco3 ice core data of atmospheric co2 between 8 ka bp and preindustrial climate can only be reproduced if co2 outgassing due to shallow water sedimentation of caco3 is considered in this case the model displays an increase of nearly 20 ppmv co2 between 8 ka bp and present day model configurations that do not contain this forcing show a slight decrease in atmospheric co2 we can therefore explain the late holocene rise in co2 by invoking natural forcing factors only and anthropogenic forcing is not required to understand preindustrial co2 dynamics