moisture and temperature changes associated with the mid holocene tsuga decline in the northeastern united states abstract a decline of hemlock tsuga populations at ca 5 5 ka thousands of calibrated radiocarbon years before 1950 ad stands out as the most abrupt vegetation change of the holocene in north america but remains poorly understood after decades of study recent analyses of fossil pollen have revealed a concurrent abrupt oak quercus decline and increases in the abundance of beech fagus and pine pinus on cape cod in eastern massachusetts but the replacement of drought tolerant oaks by moisture sensitive beeches appears inconsistent with low lake levels in the region at the same time the oak and beech changes are also limited to coastal areas and the coastal inland differences require an explanation here we develop a new lake level reconstruction from deep pond cape cod by using a transect of sediment cores and ground penetrating radar gpr profiles to constrain the past elevations of the sandy littoral zone of the pond the reconstruction shows that a series of multi century episodes of low water coincide with the abrupt hemlock and oak declines and interrupt subsequent phases of hemlock recovery the lake level variations equal precipitation deficits of 100 mm superimposed on a holocene long moisture increase of 400 mm however because moisture deficits do not easily explain the oak and beech changes we also evaluate how the climate preferences of the regional vegetation changed over time by matching the fossil pollen assemblages from deep pond with their modern equivalents reconstructions of the precipitation requirements of the vegetation correlate well even in detail with the lake level record r 0 88 at deep pond and indicate close tracking of effective moisture precipitation minus evapotranspiration by the vegetation despite the abrupt species declines which could have decoupled climate and vegetation trends reconstructions of the temperature preferences of the vegetation indicate that coastal sites may have cooled by 0 5 2 5 c after ca 5 5 ka while inland sites warmed by 0 5 1 c the change in coastal temperature preferences agrees with sea surface cooling in the western atlantic ocean of 1 c consequently the persistence of low hemlock abundance after 5 5 ka in the northeast u s may have resulted from oceanic changes that produced multi century droughts and thus delayed the post decline recovery of hemlock populations

palynological evidence for the latest oligocene early miocene paleoelevation estimate in the lunpola basin central tibet uplift of the tibetan plateau is ultimately driven by the cenozoic collision between the indian and eurasian plates and their continued convergence one approach for studying the tibetan plateau uplift is to verify the paleoelevation changes from collision to present day this is important for understanding both the tectonics and the climatic effects the new high resolution palynological record of the uppermost oligocene to the lowest miocene strata from the lunpola basin indicates that the vegetation types during the latest oligocene earliest miocene were dominated by mixed coniferous broadleaved forests being different from the modern steppe vegetation by using the coexistence approach to the fossil pollen records after calibration the effects of temperature difference and the lapse rate a maximum paleoelevation of 3190 100 m asl was estimated in the lunpola basin in the latest oligocene earliest miocene being 1500 to 2000 m lower compared with the previous oxygen isotope paleoelevation in the same region

pollen quantitative distribution in marine and fluvial surface sediments from the northern south china sea new insights into pollen transportation and deposition mechanisms in order to improve the understanding of pollen transportation and deposition mechanisms in northern south china sea scs 45 seafloor surface sediment samples from the scs and nine surface sediment samples from the pearl river mouth were analyzed palynologically the spatial distributions of pollen and spore taxa suggest that various transport mechanisms and the production at the source the dominant pollen pinus poaceae cyperaceae and fern spores are most abundant in the river mouth and decrease with increasing distance from the land suggesting they are mainly derived from the pearl river drainage basin and strongly dispersed by river plume and ocean currents which reflects a dominant pollen transportation pattern in the northern scs podoconpus and temperate broad leaved components pollen such as evergreen quercus and castanopsis pollen is common in marine samples and is scattered in the pearl river samples reflecting their extensive source areas and dispersal in more than one route however some pollen types of conifers are mostly deposited close to the shore such as dacrydium picea and abies which are restricted near hainan island and taiwan island excluding evergreen quercus and castanopsis pollen the total tropical and subtropical components poorly reflect their parent plants and fewer such pollen are transported over long distances however the source areas of some other pollen taxa e g phyllociadus artemisia and chenopodiaceae are unclear spatially varying ratios of spores to pollen indicate that spores are relatively easily transported by water over longer distances than are pollen grains this study provides a sound basis for interpreting quaternary pollen deposits from the northern scs and for further evaluation of pollen dispersal and deposition in marine and fluvial deposits c 2013 elsevier ltd and inqua all rights reserved

pollen and radiolarian records from deep sea core rc14 103 climatic reconstructions of northeast japan and northwest pacific for the last 90 000 years using modern pollen and radiolarian distributions in sediments from the northwest pacific and seas adjacent to japan to interpret floral and faunal changes in core rc14 103 44 02 n 152 56 e we recognize two major responses of the biota of eastern hokkaido and the northwest pacific to climatic changes since the last interglaciation relatively stable glacial environments 80 000 20 000 yr b p were basically cold and wet 8 c and 1200 mm mean annual temperature and precipitation respectively supporting climax broadleaf deciduous forest with quercus and ulmus zelkova with surface waters in the northwest pacific characterized by warm 1 5 c winter and cold 10 4 14 3 c summer temperatures climatic evidence from rc14 103 shows a high degree of local and regional variation within the context of global climatic change correlative ocean and land records provide the detailed input necessary to assess local regional responses to variations in other key elements i e solar radiation monsoonal variations of the northeast asian climate system

mantle dynamics postglacial rebound and the radial viscosity profile abstract we infer the radial viscosity structure of the earth s mantle from observations of long wavelength geoid glacially induced sea level changes and changes in the earth s rotation and gravitational field we employ a combination of forward and formal inverse modeling of long term mantle circulation driven by large scale density differences deduced from seismic tomography based on the resulting unscaled mantle viscosity profiles we model the time dependent glacial isostatic adjustment of the earth related to past and present changes in the ice ocean mass imbalance and we deduce scaled mantle viscosity profiles which simultaneously fit the long wavelength geoid constraint and glacially induced changes of the earth s shape three mantle viscosity profiles are fitting the observational data equally well all profiles are characterized by a two order of magnitude variation of viscosity within the earth s mantle variations of viscosity in the upper mantle are less than one order of magnitude in the lower mantle the viscosity differs significantly with depth for all models average viscosities in the upper and lower mantle are around 2 5 1020 and 1 3 1022 pa s respectively

characteristics of modern pollen distribution in surface sediment samples for the northern south china sea from three transects the present study is an analysis of the distribution of pollen in surface sediments of the northern south china sea scs as recorded in 74 samples from the area 12 00 23 72 degrees n 108 57 120 00 degrees e at water depths of 14 4410 m the characteristics of the pollen distribution along north south northeast southwest and northwest southeast directions in the northern south china sea are described below 1 based on pca analysis samples in the present study are mainly dominated by river transport component 1 pollen area i has samples with component 1 0 located in the east and south part of the study area with the dominant species of poaceae pinus water transported monolete spores podocarpus macrophyllus fungi rhizophoraceae artemisia and castanopsis transported by pearl river rivers from taiwan island mekong river pollen area ii has samples with component 1 0 they are located in the east and south around hainan island with dominant trilete spores transported by rivers from hainan island and summer monsoon forced marine current 2 the characteristics of the percentages of pollen grains were influenced mainly by the geomorphology of the seafloor pollen percentages from sample sites on the continental shelf or near islands are different from those in the sea basin the percentages of trilete spores at continental shelf or island sites are higher than those at sea basin sites 3 the pollen percentages and concentrations indicate that castanopsis and evergreen quercus pollen are most abundant in the southwest these pollen could be transported from indochina by the mekong river the percentage of castanopsis pollen decreased from north to south and from northwest to southeast indicating that the guangdong coast is a secondary source area monolete spores cyperaceae and poaceae abundances decreased from northwest to southeast related to input from the pearl river or proximity to the guangdong coast in the north south direction monolete spores and poaceae decreased from the north and from the south to the middle of the basin which can be attributed to inputs from the pearl river or guangdong coast in the north and indochina in the south c 2012 elsevier ltd and inqua all rights reserved

marine geology in the arc continent collision zone off southeastern taiwan implications for late neogene evolution of the coastal range abstract marine geology in the region between taiwan and luzon is characterized by a convergent tectonics in the south and an oblique arc continent collision in the north in the collision zone six geologic provinces are recognized they are the manila trench the accretionary prism of the hengchun ridge the sutural basin of the southern longitudinal trough the subduction melange of the huatung ridge the forearc basins of the taitung and the north luzon troughs and the volcanic arc of the north luzon ridge the oceanic crust of the south china sea is subducting eastward beneath the philippine sea plate along the manila trench south of 20 n further to the north the trench has changed progressively its axis toward the west from the subduction melanges off southeastern taiwan at 3 ma to the hengchun peninsula of southern taiwan at 2 1 ma and then to the present day location off southwestern taiwan because of the continuing collision and the westward shifting of the manila trench sediments deposited in the region are passively incorporated into the accretionary prism and deformed to the hengchun ridge after the collision the southern longitudinal trough consisting of a 2 km thick of orogenic sediments represents a sutural basin superposed on the plate boundary between the accretionary prism of the hengchun ridge asian continent and the subduction melange of the huatung ridge philippine sea plate the huatung ridge is a bathymetric high connected to the southern coastal range and is characteristic of low negative free air gravity and magnetic anomalies the ridge contains deeply weathered sedimentary blocks with abraded deep water late pliocene foraminifera and identical clay mineral compositions as those in the onshore lichi melange this implies that at least a portion of the huatung ridge is composed of melange materials and represents a former subduction zone extending from the lichi melange of the southern coastal range the north luzon trough and the taitung trough are the constructed foreac basins with 2 km of orogenic sediments unconformably overlying the volcanic islands and the subduction melange the taitung trough is southward connected to the north luzon trough through a bathymetric passage which was formed by narrowing the north luzon trough as a consequence of clockwise rotation of the lutao volcanic island during the late pleistocene a detailed study of the four neogene tectonostratigraphic units in the coastal range shows that the overall history of the formation of the range can be related to the present day geologic provinces and the on going collision processes in the region off southeastern taiwan the range had evolved from a southward accretion of the shuilien loho remnant forearc basin and the chimei volcanic pair at 2 ma followed by the chengkung taiyuan remnant forearc basin and the chengkuangao volcanic island pair at 1 ma and the taitung trough and the lutao volcanic island pair presently in process by analogy the northern part of the north luzon trough and the lanhsu volcanic island will be accreted to the coastal range in the next million years the paired forearc basin volcanic island accretion model proposed in this study may thus have implications for mountain ranges that evolved from similar tectonics of oblique arc continent collision

reply to comment by w fjeldskaar what about the asthenosphere viscosity sea level change glacial rebound and mantle viscosity for northern europe viscosity profiles that best match the observational database include a low viscosity channel in the upper mantle fjeldskaar neither point to a well developed low viscosity channel in the 2000 in our paper we clearly noted that we examined only a upper mantle and the second model compares well with the part of the possible earth model space and that we restricted results from the sea level analysis only ourselves to a three mantle layer model comprising a lithothe second reason for not pursuing the more detailed sphere an upper mantle extending from the base of the solutions for the scandinavian region is that a major limitation lithosphere down to the 670 km seismic discontinuity and a in the modelling is the inadequate knowledge of the temporal lower mantle a broad range of parameters defining these three and spatial distribution of the ice cover over the region and layers was explored and no a priori values were attached to based on tests with different ice models we concluded that this any one layer this is important in that considerable trade off was more important than differences in predictions between between parameters can result we were careful to note that the threeand five layer mantle models unless some modification analysis yielded only first order results and that the resulting of the ice sheet was permitted in the inversion this would earth model parameters are effective values that while they result in a very considerable dependence of earth model results appear to give an adequate description of the rebound evidence on the adopted ice model for example compare figs 16 a the relative sea level change and shoreline migration may and b and fig 33 b in lsj we concluded that further not be a true reflection of the actual physical layering within the improvements in the knowledge of the spatial and temporal earth we also noted that further work is required to examine distribution of the ice are required before it becomes worthwhile whether a higher degree of mantle layering is appropriate to explore the earth structure in greater detail subsequent e g p 135 inversions in lsj therefore placed greater emphasis on the ice the reason we did not conduct a more exhaustive search of model than on the detailed earth structure although care was the model space was two fold the first was that our earlier taken at all times to ensure that an adequate separation of the experience with the british rebound modelling lambeck et al earthand ice model parameters occurred 1996 led to the conclusion that five layer mantle models three inversions of independent sea level data for ice sheet including the low viscosity asthenosphere option yielded only parameters and three layered mantle parameters led to a marginal improvement in the overall comparison of preconsistent conclusions about likely ice thicknesses during latedictions of sea level change with observations fig 1 illustrates glacial times these data sets are the lateand postglacial the two sets of effective earth model parameters that were geological evidence for sea level change across the region found to be optimal for the threeand five layer models the lsj the tide gauge data for the region lambeck et al five layer model is physically more intuitive but in the british 1998b and the timing and elevation data of various baltic lake isles case it does not lead to a significant improvement in the stages lambeck 1999 in all cases thick quasi parabolic ice ability to predict lateand postglacial sea levels and shoreline models in which ice thickness increases rapidly with distance locations compared to the three layer model in this particular from the ice margin yield predictions that are inconsistent case the observational database has only limited resolving with the sea level and shoreline observations for the southern power for isolating the higher resolution structure in the mantle and southeastern scandinavia and baltic regions see also and for all predictive purposes of sea level change and shoretushingham peltier 1991 and lambeck et al 1990 with line evolution three layer or five layer models are essentially the exception of some of the norwegian coastal zones the

tests of glacial rebound models for fennoscandinavia based on instrumented sea and lake level records summary evidence for changing sea levels in northwestern europe related to glacial rebound is found in both the geological record of the past millennia and in the instrumental records of the past two centuries the latter records are of two types records of sealevel change primarily from the baltic and the gulfs of finland and bothnia and records of the tilting of some of the larger lakes in both finland and sweden the sealevel records are particularly important because of their long duration and high quality their large number and good spatial distribution and the spatially coherent background noise the two instrumental data types are complementary and provide constraints on the upper mantle rheology and on the distribution of ice during the late glacial stage comparisons of the observed rates of change of the water levels with models for glacial rebound yield earth models with a lithospheric thickness of 80 100 km and an uppermantle viscosity of 4 5 1020 pa s evective parameters that are consistent with those obtained from the analysis of the geological evidence for the same region the mareograph results support ice sheet models in which the late weichselian ice thickness over the eastern and southern parts of fennoscandia is relatively thinner than that for the western region also consistent with the interpretation of the geological evidence for sea level change in addition the instrumental records provide constraints on the eustatic sea level change for about the past 100 years a satisfactory separation of the earth rheology parameters from this rate of change can be achieved by estimating the latter only from those records for which the predicted isostatic evects are small a check on these results is possible by using the lake level records to establish constraints on the earth model parameters and the sea level records to constrain also the eustatic change all approaches lead to an average eustatic sea level rise for the past century of about 1 1 0 2 mm yr 1

palynology of eastern indonesian marine piston cores a late quaternary vegetational and climatic record for australasia abstract pollen analyses of late quaternary sediments from nine marine piston cores reveal a continuous vegetation and environmental record for eastern indonesia and northern australia on the island of halmahera a montane oak forest largely replaced the tropical lowland vegetation during the last glacial period while fern cover was strongly reduced during its maximum 18 000 yr b p climate was cooler and slightly drier than today around 10 000 yr b p mangrove vegetation expanded following the rising sea level in our western new guinea record at 14 000 yr b p climate grew warmer and slightly wetter until it stabilised around 10 000 yr b p at that time the mid to upper montane forests expanded to their full altitudinal range and fern cover increased while montane oak forest grassland and woodland areas had contracted in our marine pollen records during the last glacial the climate of northern australia was distinctly drier than today grassland vegetation with sedges increased considerably at 38 000 and 24 000 yr b p replacing eucalypt forest and culminating in a maximum grassland cover at the height of the last glaciation 18 000 yr b p the rapid sea level rise allowed the expansion of mangrove forests and salt bush marshes which had become established on the large tidal flats of the drowning sahul shelf around 12 000 yr b p one piston core g6 4 extends to 300 000 yr b p and shows that glacial periods are characterized by high pollen concentrations in marine sediments recording expanding grassland vegetation during interglacial woodland and fern cover increased while pollen concentrations in the sediments were low after 190 000 yr b p a more open vegetation suggests that conditions were in general much more arid than before repeated mangrove vegetation expansions suggest major rises in sea level at around 244 000 220 000 and 130 000 yr b p

pollen distribution in marine sediments from the south eastern indonesian waters abstract pollen analysis on box core sediments from the south eastern indonesian waters provide information on trends in pollen transport and on pollen distribution in the marine surface sediments pollen and at a lower rate pteridophyta spore concentration values tend to decrease with increasing distance from the shoreline as a result pteridophyta percentages tend to increase with increasing distance from the shoreline mangrove pollen shows very little export from its distribution area while pollen from the mid upper montane group shows a substantial export from its onshore distribution area in general despite the complex nature of vegetation patterns and pollen transport in this region the onshore distribution of individual taxa and major vegetation types is well reflected in the pollen distribution in the marine sediments

reconstructing pathways of aeolian pollen transport to the marine sediments along the coastline of sw africa the distribution of pollen in marine sediments is used to reconstruct pathways of terrigenous input to the oceans and provides a record of vegetation change on adjacent continents the wind transport routes of aeolian pollen is comprehensively illustrated by clusters of trajectories isobaric 4 day backward trajectories are calculated using the modelled wind field of echam3 and are clustered on a seasonal basis to estimate the main pathways of aeolian particles to sites of marine cores in the south eastern atlantic trajectories and clusters based on the modelled wind field of the last glacial maximum hardly differ from those of the present day trajectory clusters show three regional and two seasonal patterns determining the pathways of aeolian pollen transport into the south eastern atlantic ocean mainly transport out of the continent occurs during austral fall and winter when easterly and south easterly winds prevail south of 25 s winds blow mostly from the west and southwest and aeolian terrestrial input is very low generally a good latitudinal correspondence exists between the distribution patterns of pollen in marine surface sediments and the occurrence of the source plants on the adjacent continent the northern angola basin receives pollen and spores from the congolian and zambezian forests mainly through river discharge the zambezian vegetation zone is the main source area for wind blown pollen in sediments of the angola basin while the semi desert and desert areas are the main sources for pollen in sediments of the walvis basin and on the walvis ridge a transect of six marine pollen records along the south western african coast indicates considerable changes in the vegetation of southern africa between glacial and interglacial periods important changes in the vegetation are the decline of forests in equatorial africa and the north of southern africa and a northward shift of winter rain vegetation along the western escarpment

global miocene tectonics and the modern world abstract an amazing congruence of seemingly unrelated diverse global events began in the middle and upper miocene and established our modern world two global orogenic belts were active mostly in the middle and upper miocene while backarc basins formed along the eastern margin of asia coincident with these events global temperatures cooled in both the ocean and atmosphere desertification occurred from central asia into and across most of northern africa and also in australia and in southern south america coincident with the expansion of the antarctic ice cap at 14 ma there was initial widespread deep sea erosion and changes in patterns of deep sea sedimentation muddy pelagic sedimentation increased six fold in the north and central atlantic and pacific oceans and global changes in circulation lead to more diatomites in the pacific and fewer in the atlantic by the end of the miocene most of the mediterranean sea had evaporated broadly coincident with these events many old large river systems were destroyed and new ones formed as much of the world s landscape changed collectively these global on shore tectonic and ocean atmospheric events provide the foundation for our modern world a mixture of new and rejuvenated orogenic belts and their far field effects distant epiorogenic uplift rain shadow deserts large alluvial aprons and distant deltas as inherited gondwanan landscapes persisted remote from plate boundaries thus at the end of the miocene much of the world s landscape except for that changed by pleistocene continental glaciation would be recognizable to us today we argue that all of these events had the same ultimate common cause an internal earth engine that drove plate motions in two broad ways first the opening and closing of seven key gateways to deep water oceanic currents radically altered global heat transfer and changed a lingering greenhouse to an icehouse world secondly these events were in part coincident with renewed heat flow in the african and pacific superplumes that energized global plate motions in the middle and upper miocene we hope this global synthesis will stimulate more research on the many global events of the miocene to understand better both our modern world and earlier global orogenies

sea level change glacial rebound and mantle viscosity fornorthern europe northwestern europe remains a key region for testing models of glacial isostasy because of the good geological record of crustal response to the glacial unloading since the time of the last glacial maximum models for this rebound and associated sea level change require a detailed knowledge of the ice sheet geometry including the ice thickness through time existing ice sheet reconstructions are strongly model dependent and inversions of sea level data for the mantle response may be a function of the model assumptions thus inverse solutions for the sea level data are sought that include both ice and earth model parameters as unknowns sea level data from fennoscandia the north sea the british isles and the atlantic and english channel coasts have been evaluated and incorporated into the solutions the starting ice sheet for fennoscandia is based on a reconstruction of a model by denton hughes 1981 that is characterized by quasi parabolic cross sections and symmetry about the load centre both global northwestern europe as a whole and regional subsets of the data solutions have been made for earth model parameters and ice height scaling parameters the key results are as follows 1 the response of the upper mantle to the changing ice and water loads is spatially relatively homogenous across scandinavia the north sea and the british isles 2 this response can be adequately modelled by an effective elastic lithosphere of thickness 65 85 km and by an effective upper mantle viscosity from the base of the lithosphere to the 670 km depth seismic discontinuity of about 3 4 1020 pa s the effective lower mantle viscosity is at least an order of magnitude greater 3 the ice thickness over scandinavia at the time of maximum glaciation was only about 2000 m much less than the 3400 m assumed in the denton hughes model 4 the ice profiles are asymmetric about the centre of the ice sheet with those over the western part being consistent with quasi parabolic functions whereas the ice heights over the eastern and southern regions increase much more slowly with distance inwards from the ice margin

temporal density of pollen sampling affects age determination of the mid holocene hemlock tsuga decline abstract in establishing the age of a past event emphasis has been placed on dating accuracy precision calibration and age model development while the importance of adequate sampling and accurate reconstruction of the event itself is often neglected here we evaluate effects of temporal sampling density on stratigraphic and hence chronological placement of an event horizon using the mid holocene hemlock decline as an example results from simulations on theoretical and actual high resolution pollen sequences suggest that the pollen sampling density has a critical impact on the stratigraphic placement of the hemlock decline horizon and in turn on age estimation of the event also decline age frequency distributions from multiple sites were affected by sampling density therefore the hemlock decline should be used with caution as a precise chronostratigraphic marker and the current dataset of hemlock decline records may not be sufficient to analyze the spatiotemporal pattern of the hemlock decline finally we propose criteria for obtaining adequately sampled records in studying an event and estimated the adequate sampling density for age estimation of the mid holocene hemlock decline

miocene climate evolution of northern europe a palynological investigation from denmark a palynological investigation has been conducted on lower upper miocene sediments from jylland denmark corresponding to the time interval of about 19 to 8 ma the sediments derived from the sdr vium drill core were deposited in marine to marginal marine environments as shown by the relatively high abundance of dinoflagellate cysts in all samples nevertheless rich and diverse pollen assemblages occur throughout the succession and the palynological analysis reveals that coastal areas of the study area were during the miocene dominated by taxodium swamp forests that also hosted terrestrial angiosperms such as nyssa betula alms and elements of the myricaceae further inland a mixed deciduous evergreen forest prevailed in areas with better drained soils or on elevated areas gymnospermous conifer forests prevailed including taxa such as pinus sequoia and sciadopitys overall the climate in the study area was warm temperate during major parts of the miocene with mean annual temperatures between 15 5 and 20 degrees c by employing the coexistence approach combined with the method of allocating taxa into standardized climatic groups four different climatic miocene events are detected within the studied succession correlated to the coeval climate record of northwestern europe the oldest event is a cooling during the earlier burdigalian at approximately 19 ma coinciding with the mbi 1 oxygen isotope excursion at ca 18 5 ma in mid burdigalian a warming phase is reconstructed characterized by the highest precipitation rates observed in the sedimentary succession a warming trend starting in the latest burdigalian corresponds to the globally recognized middle miocene climatic optimum mmco while a longer term late neogene cooling was initiated in the mid serravallian about 13 ma c 2011 elsevier b v all rights reserved less

deep sea pollen from the south china sea pleistocene indicators of east asian monsoon abstract a high resolution pollen record sampling interval averages 820 years has been obtained from odp site 1144 water depth 2037 m northern south china sea the 504 m sequence in composition length covers the last 1 03 million years according to micropaleontological and isotopic stratigraphy the pollen assemblages are characterized by high proportions of pinus and herb pollen and by their frequent alternations based on these alternations 29 pollen zones have been recognized that are closely correlated to the marine oxygen isotope stages mis 1 29 pinus dominant pollen zones correspond to interglacial periods with lighter 18o values while herb marked ones relate to the heavier 18o stages assigned to glacials judging from the pollen data the exposed northern continental shelf of the south china sea during the glacials was covered by grassland and the extensive northern shelf has formed only since mis 6 ca 150 ka probably as a result of tectonic subsidence tree pollen influx values are indicative of winter monsoon which began to intensify 600 ka ago the summer monsoon variations can be approximated by the fern percentage within the total pollen and spore abundance and the result shows high values in general occurring at interglacials with the maxima at mis 15 5e and 1 the relatively high fern percentage with smaller amplitude in variations before 600 ka might suggest more stable humid conditions before the intensification of winter monsoon

changes in terrestrial ecosystem since 30 ma in east asia stable isotope evidence from black carbon in the south china sea a 30 m y stable isotopic record of marine deposited black carbon from regional ter restrial biomass burning from the northern south china sea reveals photosynthetic path way evolution for terrestrial ecosystems in the late cenozoic this record indicates that c3 plants negatively adjusted their isotopic discrimination and c 4 plants appeared grad ually as a component of land vegetation in east asia since the early miocene a long time before sudden c4 expansion occurred during the late miocene to the pliocene the changes in terrestrial ecosystems with time can be reasonably related to the evolution of east asian monsoons which are thought to have been induced by several intricate mechanisms during the late cenozoic and could contribute significantly to the post miocene marine carbonate isotope decline

ice 3g a new global model of late pleistocene deglaciation based upon geophysical predictions of post glacial relative sea level change a new high resolution global model of late pleistocene deglaciation is inferred on the basis of geophysical predictions of postglacial relative sea level variations in which the ice ocean solid earth interaction is treated in a gravitationally self consistent fashion for the purpose of these analyses the radial viscoelastic structure of the planet is assumed known on the basis of previously published sensitivity tests on solutions of the forward problem only radiocarbon controlled relative sea level histories from sites that were actually ice covered with one or two additions are employed to constrain the model leaving relative sea level rsl data from sites that were not ice covered to be employed to confirm its consistency results for these confirmatory analyses are reported elsewhere here the new deglaciation model referred to as ice 3g is compared to previous models derived by several independent means and tested against a number of additional observations other than sea level histories including geologically controlled retreat isochrones oxygen isotope data from deep sea sedimentary cores and coral terrace elevations the latter two observations strongly constrain the net sea level rise that has occurred since the onset of deglaciation and therefore the mass of ice that melted during the last glacial interglacial transition

pollen evidence of the palaeoenvironments of lufengpithecus lufengensis in the zhaotong basin southeastern margin of the tibetan plateau evolutionary processes in hominoid primates were closely related to global and or regional environmental changes and therefore palaeoenvironmental reconstruction is fundamental for understanding how environmental changes shaped their evolution here we present pollen data from the 16 m thick shuitangba stb section yunnan province southwestern china bearing remains of the hominoid lufengpithecus lufengensis of the terminal miocene and use principal component analysis to reconstruct the palaeovegetation and palaeodimate during the key period when the hominoid lived our results show that before the stb hominoid appeared zone a the vegetation was dominated by subtropical evergreen broad leaved taxa with a few temperate deciduous taxa e g quercus castanea castanopsis alnus the development of aquatic plants commencing at the similar to 12 m depth is a prominent feature indicating a warm and humid climate during the time when the hominoid lived zone b evergreen broad leaved forests with evergreen quercus were predominant while grasses including poaceae began to expand and simultaneously conifers decreased indicating a warm climate the significant presence of aquatic pollen taxa in subzone a 2 and zone b suggests the occurrence of lacustrine or swampy environments in contrast in zone c the vegetation changed to coniferous forest indicating cooler and drier conditions these results provide substantive evidence of the vegetation conditions when the hominoid lived suggesting that the greater diversity of vegetation and the warm humid climate compared to the present day would have favoured its survival c 2015 elsevier b v all rights reserved

glacial rebound of the british isles iii constraints on mantle viscosity summary observations of sea level change since the time of the last glacial maximum provide important constraints on the response of the earth to changes in surface loading on time scales of 103 104 years this response is conveniently described by an effective elastic lithospheric thickness and effective viscosities for one or more mantle layers considerable trade off between the parameters describing these layers can occur and different combinations can give rise to comparable predictions of sea level change in particular the trade off between lithospheric thickness and upper mantle viscosity can be important and for any reasonable value for the lithospheric thickness a corresponding mantle viscosity structure can be found that gives a plausible comparison of sealevel predictions with observations in particular thin lithosphere models will lead to low estimates for the upper mantle viscosity while thick lithosphere models lead to high viscosity values however either solution may represent only a local minimum in the model parameter space and may not correspond to the optimum solution it becomes important therefore that in the inversion of observational data a comprehensive search is conducted throughout the entire model parameter space to ensure that the solution identified does indeed correspond to the optimum solution the sea level data for the british isles lend themselves well to such an inversion because of the relatively high quality of the data the good geographic distribution of the data relative to the former ice sheet and reasonable observational constraints on the dimensions of the former ice sheet and on its retreat furthermore because of the contribution to the sea level signal from the distant ice sheets as well as from the melt water load the observational data base for the region also has some resolving power for the viscosity of the deeper mantle the parameter space explored is defined by up to five mantle layers the lithosphere of effective elastic thickness d and a series of upper mantle layers i 2 4 extending down to depths of 200 400 and 670 km respectively each of viscosity qi and a lower mantle layer of viscosity qlm extending down to the coremantle boundary the range of parameters explored is 30 d i 120 km 3 x loi9 iqi

shoreline displacements in southern central sweden and the evolution of the baltic sea since the last maximum glaciation during late and post glacial times the baltic basin has been periodically isolated from the atlantic and freshwater and saline conditions have alternated this is a consequence of the interactions between the spatially variable glacial rebound of the region and the simultaneous eustatic sea level rise in the adjacent atlantic observations of the timing of these isolations and of the location of the barriers therefore provide constraints on the rebound models high resolution numerical models of rebound of southern sweden the danish straits and the baltic have been developed and tested against observations of lake level change as well as against the observed elevations of the last baltic ice lake shoreline which formed before about 10 3 ka bp predictions of sea and lake levels are used to test two alternative hypotheses about the ice thickness over scandinavia and to estimate parameters that describe the earth s response optimum values for the latter are lithospheric thickness of 60 20 km upper mantle viscosity of 3 3 10 20 pa s and lower mantle viscosity of 10 22 pa s the rapid lake level fall at the end of the baltic ice lake stage is estimated to be 30 5 m the optimum ice model for scandinavia is one in which the ice thickness over southeastern and southern scandinavia was relatively thin compared with the ice thickness over sweden and norway the ice thickness in the southeast and south changes slowly with distance inwards of the ice margin whereas over sweden and norway the ice thickness profiles are considerably steeper the earth and ice models have been combined with high resolution digital terrain data to develop a comprehensive model for the evolution of the baltic basin since the time the area last became ice free the reconstructions predict the occurrence of barriers at certain times which impede free flow between the atlantic and baltic and confirm that the baltic lake levels are controlled by rebound at four localities degerfors in the narke region of southern central sweden the vanern outlet through the gota alv oresund and the darss langelands store baelts in denmark

middle pleistocene seismically induced clay diapirism in an intraplate zone western brittany france the brittany region of france is located in a low seismicity intraplate zone most of the instrumented earthquakes are limited to a shallow crustal depth without surface rupture a paleoseismological analysis was performed on deposits on the crozon peninsula and in the elorn estuary we highlight hydroplastic deformations induced by liquefaction leading to clay diapirism which were likely triggered by past earthquakes this diapirism seems to be frequent in continental nonconsolidated sediments and to develop on the inherited tectonic structures when a shallow water table and confining layers exist timing of deformation is dated using paleoenvironmental data and electron spin resonance and infrared stimulated luminescence dating methods two seismic periods were identified in western europe during early marine oxygen isotope stage mis 10 380 ka and early mis 8 280 265 ka the lack of similar deformations affecting the holocene tidal deposits in the bay of brest suggests that the magnitude of the triggering paleoearthquakes is probably higher m w 6 than the recent events m w 5 4 these unusual intraplate major paleoearthquakes need specific factors affecting the far field crustal stress loading to be triggered such as a brief acceleration of the africa eurasia lithospheric plate convergence glacio isostatic stress perturbations associated with the onset of major glaciations in northern europe or other processes induced by orbital forcing

mid late miocene vegetation and environments in southeast china insights from a marine palynological record in northwestern taiwan abstract taiwan island represents the exposed accretionary prism developed by eastward subduction of south china sea scs oceanic lithosphere beneath the philippine sea plate since the middle miocene there are many well documented data about the biostratigraphic correlation except for palynological studies here we present a new palynological record of mid late miocene deposits from the chuhuangkeng section miaoli northwestern taiwan which reveals a vegetation and paleoelevation reconstruction in southeast china during the middle to late miocene corresponding to the time interval of about 14 5 5 5 ma most samples yielded well preserved palynomorphs and the palynological results suggest that the dominant vegetation was the mixed coniferous broadleaved forests in the coastal mountains of southeast china cmsc during the mid late miocene moreover based on large amounts of tsuga and picea pollen we hypothesized that a subalpine conifer forest then flourished in the cmsc and the estimated maximum paleoelevation might be up to 3000 m above sea level a s l during the mid late miocene being 1000 1500 m higher than today these findings offer a new perspective to comprehend the paleotopographic evolution of china and the source area of taiwan s spruce forests additionally the high abundance of pinus tsuga picea pollen and fern spores also suggests an enhancement of the easm during the mid late miocene

analysis of microgrowth patterns of the american oyster crassostrea virginica in the middle atlantic region of eastern north america archaeological applications abstract analysis of modern control samples of the american oyster crassostrea virginica from the chesapeake bay shows that reliable estimates of season of death can be derived from analyses of shell microgrowth structures on the anterior nympha of the hinge area application of the technique to prehistoric delmarva peninsula oyster shell midden samples shows considerable temporal and spatial variation in the seasonal utilization of oysters

planktic foraminiferal biostratigraphy and datum planes in the neogene sedimentary sequence in taiwan abstract the neogene sequences are well developed in western taiwan and they form paleontologically the best known interval of the sedimentary column of the island the succession of planktic foraminifera datums and epoch boundaries in the taiwan neogene are discussed with reference to a generalized range chart and the lithostratigraphic units biostratigraphic ranges of these species in the neogene sections of western taiwan allow establisment of eighteen foraminiferal datum planes useful for intraregional as well as international stratigraphic correlations

what about the asthenosphere viscosity comment on sea level change glacial rebound and mantle viscosity for northern europe by k lambeck c smither and p johnston lambeck et al 1998a hereafter lsj present a thorough in my own studies fjeldskaar 1994 1997 i have shown that the best fitting models have a low viscosity asthenosphere study of the sea level change connected to the deglaciation of fennoscandia they establish a comprehensive observational based on fjeldskaar 1994 the thickness and viscosity of the asthenosphere are not precisely determined but are within database on crustal rebound for the whole of northern europe this database is used in a high resolution modelling of the the range shown in fig 1 it is clearly demonstrated that the asthenosphere has a thickness of less than 150 km a thicker rebound based on the observed deglaciation pattern a key result is an estimate of the effective elastic thickness of the asthenosphere shows significant discrepancies from the observed uplift data lithosphere and the viscosity structure of the mantle lsj give a brief overview of previous results on the mantle models similar to the one favoured by lsj were tested in fjeldskaar 1994 model no 14 it was pointed out that models rheology models established by a similar approach lsj s comment to models with a low viscosity asthenosphere and with a lower mantle viscosity of 2 0 1021 pa s or higher without a low viscosity asthenosphere are not viable options the various other previously published viscosity models is that the differences are attributable to a number of factors these reason is that the short wavelength components decay too slowly giving significant deviations in central parts of the uplift dome factors include the fact that the other studies used only a subset of the data and that some of them assumed the ice sheet to be this is clearly demonstrated in the theoretical present uplift pattern calculated with the rheology parameters of lsj given perfectly known a third factor is that none of the studies has examined the entire range of possible earth model parameters in lambeck et al 1998b the predicted present day uplift centre lies further to the west than the observed centre this would this immediately gives the reader the impression that lsj do not have similar shortcomings and that the final resulting not be the case if a low viscosity asthenosphere was used fjeldskaar 1994 fig 6 furthermore the rheology model of earth rheology model is better constrained than the previous studies however this is not the case lsj have ignored models lsj cannot produce the observed shoreline tilts fjeldskaar 1994 this is also demonstrated in lsj figs 28 and 29 with a low viscosity asthenosphere on this basis it is rather peculiar that they 1 criticize others for not having used the in conclusion lsj have not been able to come up with a model for the earth rheology that gives optimum fit to entire range of possible earth models and 2 give the reader the impression that models with a low viscosity asthenosphere the observed rebound because models with a low viscosity asthenosphere have not been considered the lsj rheology is are unrealistic

holocene glacial rebound and sea level change in nw europe summary observations of late pleistocene and holocene sea level change relative to the crust exhibit very considerable variations across nw europe in consequence of the response of the earth s crust to the deglaciation of fennoscandia and of the water added to the oceans from the melting of all late pleistocene ice sheets inversion of sea level observations from a site near the centre of the fennoscandian ice sheet and from three sites located beyond the margin of the ice sheet at the time of maximum glaciation yield a range of plausible models for the earth s response and for the ice models further constraints on this range of models is placed by a comparison of observed sea levels with predicted values at other sites near the former ice sheet margins the resulting mantle parameters are upper mantle viscosity 3 5 x 10 pa s lower mantle viscosity 2 7 x loz1 pa s lithospheric thickness 100150 km these values represent effective parameters that describe the response of the earth to surface loading of short to intermediate wavelengths on a time scale of 104yr the lower mantle viscosity is poorly constrained but the marked increase from upper to lower mantle is a characteristic of all plausible solutions the inversion places a constraint on the total volume of ice in the fennoscandian ice sheet such that the equivalent sea level rise from this contribution is about 13 14 m a less well determined constraint of about 10 m equivalent sea level rise is suggested for the barents kara ice sheet the inversion also indicates that a small amount of melt water from ice sheets far away from europe continued to be added into the oceans during late holocene time so as to raise the equivalent sea level by about 3 m during the past 6000 yr consistent with similar inversions of data from sites in the australian and pacific regions

vegetation and climatic changes of sw china in response to the uplift of tibetan plateau abstract to understand the vegetation succession and climatic changes at the southeastern margin of the tibetan plateau in the neogene we reconstructed the middle miocene vegetation and climate based on palynological data from four localities which are at different latitudes along the ailao mountains in yunnan southwest china the palynological assemblages suggest that the vegetation there was composed of mixed evergreen and deciduous broad leaved forests growing under subtropical conditions based on the palynological data the palaeoclimatic parameters from the four localities are established the new parameters were compared with those of the late miocene of the late pliocene and of today the comparison revealed that the temperatures were obviously lower in the middle miocene than they are today this suggested that the ailao mountains were not high enough to block the asian winter monsoon in the middle miocene the middle miocene vegetation at the southeastern edge of the tibetan plateau was also compared to that of central tibet it would appear that the palaeoclimate at the southeastern edge of the tibetan plateau was warmer and wetter than in central tibet in contrast to the neogene cooling in central europe the climate at the southeastern edge of the tibetan plateau has gradually warmed since the middle miocene this phenomenon was most likely caused by the uplift of the tibetan plateau which has succeeded in blocking the asian winter monsoon since the middle miocene