persistent solar influence on north atlantic climate during the holocene surface winds and surface ocean hydrography in the subpolar north atlantic appear to have been influenced by variations in solar output through the entire holocene the evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon 14 and beryllium 10 and centennial to millennial time scale changes in proxies of drift ice measured in deep sea sediment cores a solar forcing mechanism therefore may underlie at least the holocene segment of the north atlantic9s 1500 year cycle the surface hydrographic changes may have affected production of north atlantic deep water potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally

late holocene variability in pelagic fish scales and dinoflagellate cysts along the west coast of vancouver island ne pacific ocean fish stocks and dinoflagellates are essential components of the marine food chain sediment cores from a predominantly anoxic basin in effingham inlet vancouver island british columbia archive a late holocene 500 5300 years bp record of paleoproductivity in the north american coastal upwelling domain cud we present evidence that late holocene changes in the dinoflagellate cyst assemblages sedimentary record and fish stocks in the northeastern pacific ocean fluctuated at least partially in accordance with regional and global climate cycles principal components analysis pca and trend wavelet and spectral analyses were used to identify relationships cycles and trends in sediment grey scale values and the abundances of fish scales and dinoflagellate cysts on centennial to millennial time scales most observed cycles fluctuated in intensity over time particularly following transition of the regional climate to a higher rainfall phase that impacted coastal oceanic dynamics 3400f150 years ago correlation of the marine paleoproductivity records observed in effingham inlet with solar influenced climate proxy cycles observed in the north atlantic region indicates that solar forcing at different scales might have influenced the climate in the northeast pacific as well in particular an 1100 to 1400 year cycle in regional climate is well represented in the fish productivity proxy and sedimentological record it was also observed that colder water high productivity selenopemphix nephroides and anchovydominated banchovy regimeq ecosystems alternate with warmer water herring dominated bherring regimeq ecosystems at millennial time scales the fish scale record preserved in effingham inlet indicates that the ne pacific is now in transition from an danchovy t to a dherringt dominated regime d 2005 elsevier b v all rights reserved

periodicity of climate conditions and solar variability derived from dendrochronological and other palaeoclimatic data in high latitudes abstract the periodicity of climatic processes in the barents sea region and along the arctic ocean coast during several hundred years has been studied by analyzing the tree ring chronologies for the regions close to the northern timberline in the barents sea region cyclicities of climatic processes with periods of around 90 30 35 22 23 18 and 11 12 years have been established by spectral analysis of the data for the kola peninsula wavelet analysis of annual series of conifer tree rings generalized for 10 regions along the northern timberline from the kola peninsula to chukotka for the period 1458 1975 has revealed the same periodicities for the vast areas of northern russia climatic cyclicity with a period of about 35 years is known as the bruckner cycle climatic cycles with periods of around 90 22 23 and 11 12 years correlate well with the corresponding solar activity cycles a possible solar forcing of periodic climatic processes and its nonlinear influence on the atmosphere ocean continental system are discussed

high resolution holocene vegetation history and climate from hole 1034b odp leg 169s saanich inlet canada abstract high resolution pollen analysis of laminated marine sediments from odp hole 1034b in saanich inlet british columbia reveals changes in vegetation and inferred climate during the holocene four main pollen zones are discerned using constrained cluster analysis although the timing of major vegetation changes at the saanich inlet is similar to other study sites in the pacific northwest the composition of pollen assemblage zones is different from the mainland sites vegetation assemblages reconstructed from the pollen and spore record include a douglas fir pseudotsuga menziesii parkland with abundant grass poaceae and bracken pteridium between 11 450 and 8300 bp all ages are calibrated calendar years oak quercus savanna or parkland with high grass and bracken 8300 7040 bp a mixed deciduous coniferous forest with oak western hemlock tsuga heterophylla and douglas fir 7040 5750 bp and the development of modern coastal temperate forest with the marked expansion of cedar cupressaceae western hemlock spruce picea and douglas fir 5750 1050 bp climatic periods inferred from the cores include an early holocene warm dry interval 11 450 8300 bp a warm period with mild winters 8300 7040 bp a period of transitional mid holocene climate 7040 5750 bp and the advent of a relatively cool wet neoglacial climate after 5750 bp modern conifer forests and oak savannas became established by about 3800 bp the saanich inlet pollen record indicates that vegetation and inferred climate change was particularly rapid between 8700 and 8300 bp when grass and bracken abruptly decrease and oak becomes a significant component of the paleovegetation because neoglacial conditions have prevailed from 3800 years to present in the pacific northwest factors other than climate such as anthropogenic modification of the landscape may be responsible for the persistence of oak savannas

interannual to multidecadal timescale climate variations in the northeast pacific abstract analysis of five long term coastal air temperature records reconstructed from tree ring growth patterns indicate that the climate of the northeast pacific ocean has oscillated at three dominant timescales over the last 400 years the well known 2 8 yr el nino southern oscillation enso timescale a 20 40 yr interdecadal timescale and a 60 80 yr multidecadal timescale the latter oscillation has been the dominant mode of air temperature variability along the west coast of north america over the last 400 years during this period there have been conspicuous temporal modulations of the enso and the interdecadal signals low frequency temperature oscillations at periods greater than 10 years in the northeast pacific have been significantly coherent and in phase from southern california to british columbia however with the exception of the enso signal higher frequency variability has been weakly coherent along the west coast recent work suggests that the interdecadal oscillation is a worldwi

north atlantic oscillation dynamics recorded in greenland ice cores carefully selected ice core data from greenland can be used to reconstruct an annual proxy north atlantic oscillation nao index this index for the past 350 years indicates that the nao is an intermittent climate oscillation with temporally active coherent and passive incoherent phases no indication for a single persistent multiannual nao frequency is found in active phases most of the energy is located in the frequency band with periods less than about 15 years in addition variability on time scales of 80 to 90 years has been observed since the mid 19th century

scaling in turbidite deposition abstract we propose that the distribution of layer thicknesses of turbidite deposits that show minimal erosional truncation and amalgamation should obey the power law n h h b where n h is the number of layers of thickness greater than h and b 1 we support this proposal with two sets of observations one from formation microscanner images obtained in offshore wells that penetrate tertiary fore arc turbidites hiscott et al 1992 and the other from our own field measurements of turbidites in the neoproterozoic kingston peak formation deposited in a glacially influenced rift basin both sets of observations show roughly the same power law distribution above a small h cutoff otivated by the possible generality of these results and given strong geological and sedimentological contrasts between the two data sets we consider the available theoretical and experimental evidence that could support or deny these observations we tentatively conclude that the power law is generic in data sets characterized by minimal erosional truncation and amalgamation but emphasize that further study is required for a definitive statement proceeding from the assumption that the scaling law is valid for arbitrarily thin layers we derive an upper bound for b we then detail simple and plausible assumptions that provide a theoretical estimate of b we discuss possible ramifications of this analysis for the interpretation of further data

the role of global and local factors in determining the middle to late holocene environmental history of the south kurile and komandar islands northwestern pacific abstract the study of holocene deposits from northwestern pacific islands is very important for understanding the natural development of the area in the context of oceanic climate strong microclimate variability and the influence of contrasting marine currents holocene sections from bering island record the following events cooling at about 4600 4500 yr bp warming at about 3500 3400 yr bp cooling at about 3000 yr bp sea level rise up to 1 5 m at about 2700 bp cooling at about 1800 1400 yr bp and sea level rise at about 1000 yr bp on the south kuriles a dry and cool climate changed to warm and moist about 7000 6500 yr bp later than on hokkaido island at this time the kuroshio current system became more active and birch assemblages were replaced by cool temperate broadleaf forests and mixed coniferous broadleaf forests at the holocene optimum about 6000 yr bp temperate broadleaf forest occupied almost all of kunashir and the okhotsk side of iturup and the climate was warmer than present the highest sea level position reached was 2 5 3 m above present level about 6500 6300 yr bp during the cooling about 4700 4500 yr bp island vegetation changed slightly due to the influence of warm currents major sea level regression during this period led to the formation of extensive coastal dune fields the warming at the beginning of the late holocene was almost as great as that of the holocene optimum two minor transgressions are recorded the vegetation changes and climatic deterioration that took place in the second half of the late holocene resulted in either a disappearance of thermophylous taxa or in a southward shift of their natural habitats during the cooling from 1700 to 1300 yr bp the isthmus area increased coastal wetlands with lakes and coastal dunes with paleosols were formed and grassland and swamp landscapes developed late holocene warming was not intensive volcanic impact on environments led to changes in vegetation assemblage swamping of the area and thick soil profile formation

a fast and easy method to derive highest resolution time series datasets from drillcores and rock samples abstract we present a fast method to obtain highest resolution greyvalue datasets from digital core images these datasets are processed using a software package developed by us artificially introduced trends in the datasets are corrected disturbances i e cracks voids are eliminated to reduce the high level noise in data we have developed a vector filter that effectively removes such noise application of the method to odp drillcores from the santa barbara basin allowed exact correlation of two drillcores from the same basin the influence of the termination of the last glacial cold period on the flux rates in the basin are reflected in the greyvalue datasets we found a transitional period of about 3000 yr between the end of the last glacial cold period and the onset of post glacial climatic oscillation in the basin fourier analyses show that the high resolution greyvalue time series record climatic cycles with frequencies as high as 1 cycle yr varves

possible solar forcing of century scale drought frequency in the northern great plains a 2100 yr decadal resolution salinity and aridity proxy record of lacustrine ostracode shell mg ca ratios from a closed basin lake in the northern great plains shows statistically significant periodicities of 400 200 130 and 100 yr these periodicities are similar to the three principal solar oscillation periods 420 218 143 yr as inferred from the atmospheric radiocarbon record suggesting strong solar forcing of century scale drought frequency with a fundamental 400 yr period and its 2nd 3rd and 4th harmonics our proxy record correlates visually and statistically cross spectral analysis with the atmospheric 14 c record solar proxy and the gisp2 greenland ice sheet project two 18 o record climate proxy showing that solar minima are in phase with drought periods in the northern great plains and cold periods in greenland this spectral similarity together with phase correlation indicates a possible teleconnection of century scale global climate fluctuations through common solar forcing

climate cyclicity in late holocene anoxic marine sediments from the seymour belize inlet complex british columbia abstract an 8 72 m late holocene sediment core vec02a07 obtained from alison sound in the belize seymour inlet complex of central british columbia canada was deposited between 3500 1000 yr bp under primarily anoxic marine conditions this core contains a detailed cyclic record of land sea interactions as evidenced by significant fluctuations in marine primary productivity and changes in the supply of terrigenous material that can be related to long term variation in the relative influence of the aleutian low al and north pacific high nph sedimentologically the core is characterized by alternating intervals of fine grained massive intervals 70 laminated intervals 23 turbidites 5 and graded silt clay layers 2 the laminated intervals are comprised of couplets that vary between light coloured diatom rich layers deposited primarily during the summer months and dark coloured mineral rich layers deposited during winter laminated couplets are most common in portions of the core deposited between 3150 and 2700 yr bp which corresponds to an episode of regional neoglaciation time series analysis was carried out on high resolution particle size measurements obtained from core sub samples and on sediment grey scale colour variability derived from x ray scans of the core non linear time series analyses revealed that the succession of massive and laminated sedimentation displayed characteristics of self organization following a power law relationship for core length segments of 13 cm 50 years of deposition contained evidence of sedimentary depositional cycles of 70 96 135 155 and 250 330 years that reflect changes in al and nph mediated regional precipitation patterns that can in turn be related to larger scale climate drivers such as the pacific decadal oscillation pdo or solar irradiance cyclicity

symmetries in geology and geophysics symmetries have played an important role in a variety of problems in geology and geophysics a large fraction of studies in mineralogy are devoted to the symmetry properties of crystals in this paper however the emphasis will be on scale invariant fractal symmetries the earth s topography is an example of both statistically self similar and self affine fractals landforms are also associated with drainage networks which are statistical fractal trees a universal feature of drainage networks and other growth networks is side branching deterministic space filling networks with side branching symmetries are illustrated it is shown that naturally occurring drainage networks have symmetries similar to diffusion limited aggregation clusters

climate shift at 4400 years bp evidence from high resolution diatom stratigraphy effingham inlet british columbia canada abstract diatom paleoecology and climatic interpretations were assessed from a 15 cm long laminated sediment slab extracted from an anoxic fjord in southwest british columbia the slab spans at least 62 years of deposition determined from counting varves and is dated at approximately 4400 years bp the slab shows a sedimentation pattern where thick diatom rich varves at the bottom become thinner and more silty toward the top thin section analysis reveals that the thicker varves contain a distinct succession of diatoms representing seasonal deposition throughout each year annual scale subsampling shows that the abundance of coastal marine diatoms namely a weakly silicified form of skeletonema costatum decreased over the 62 year period while benthic and brackish water diatoms such as planothidium delicatulum and achnanthes minutissima increased with the concomitant increase in silt the increase in such benthic species and silt along with the presence of 1 cm thick nonlaminated intervals is interpreted to represent deposition during progressively increasing precipitation over time these sedimentation patterns and changes in diatom assemblages may signify a change in the relative intensities of the aleutian low al and north pacific high nph atmospheric pressure systems thicker diatomaceous varves at the bottom of the slab reflect a stronger nph system with associated coastal upwelling and enhanced diatom production the thinner silty varves at the top of the slab suggest that the al system was prevalent resulting in greater amounts of precipitation and reduced upwelling the findings of this study show that significant natural environmental change can occur within a twenty year time frame and can provide a basis for the study of modern change in the ocean atmosphere system over the northeast pacific ocean

late holocene sedimentary response to solar and cosmic ray activity influenced climate variability in the ne pacific marine laminated sediments along the ne pacific coast effingham inlet vancouver island provide an archive of climate variability at annual to millennial scales a 7 75 m portion of piston core tul99b 03 was deposited during a 3045 year interval 1440 4485 years before present ybp under primarily anoxic conditions darker clay laminae were deposited under higher precipitation conditions in winter and diatom dominated laminae were laid down when marine productivity was higher in the spring through autumn wavelet transform and other time series analysis methods were applied to sediment color i e gray scale values line scans obtained from x ray images and compared with global records of cosmogenic nuclides 14 c and 10 be as well as the ice drift index hematite stained grains record to detect cycles trends and nonstationarities in the climate and sedimentary pattern our results show that the marine sedimentary record in the ne pacific responded to abrupt changes and long term variability in climate that can be linked to external forcing e g solar and cosmic irradiance specifically a strong cooling in the ne pacific at 3550f160 ybp can be correlated to a weakening of high frequency 50 150 years pulses in sun activity at the gleissberg cycle band similar to what occurred at the onset of the dlittle ice aget at 1630 ad three intervals of unusually low sun activity at 2350 2750 and 3350 ybp are characterized by thick clay rich annual sedimentation that we interpret as representative of unusually wet conditions these intervals of higher precipitation conditions may have been related to a regional intensification of the aleutian low al caused by an eastward migration of the center of action coa of the al which occurs during intervals of solar minima dryer conditions in the region occur when the coa of al migrates westward and the coa of the north pacific high nph migrates northward during intervals of solar maxima a cyclicity of 50 85 33 36 and 22 29 years in the sediment color record lamination thickness and 14 c cosmogenic nuclide characterized the relatively warm interval from 3550 to 4485 ybp this record is similar to that of present day low and highfrequency variants of the pacific decadal oscillation and aleutian low d 2004 elsevier b v all rights reserved

cyclic variation and solar forcing of holocene climate in the alaskan subarctic high resolution analyses of lake sediment from southwestern alaska reveal cyclic variations in climate and ecosystems during the holocene these variations occurred with periodicities similar to those of solar activity and appear to be coherent with time series of the cosmogenic nuclides 14c and 10be as well as north atlantic drift ice our results imply that small variations in solar irradiance induced pronounced cyclic changes in northern high latitude environments they also provide evidence that centennial scale shifts in the holocene climate were similar between the subpolar regions of the north atlantic and north pacific possibly because of sun ocean climate linkages

forecasting the path of a laterally propagating dike an important aspect of eruption forecasting is predicting the path of propagating dikes we show how lateral dike propagation can be forecast using the minimum potential energy principle we compare theory to observed propagation paths of dikes originating at the bar arbunga volcano iceland in 2014 and 1996 by developing a probability distribution for the most likely propagation path the observed propagation paths agree well with the model prediction we nd that topography is very important for the model and our preferred forecasting model considers its in uence on the potential energy change of the crust and magma we tested the in uence of topography by running the model assuming no topography and found that the path of the 2014 dike could not be hindcasted the results suggest that lateral dike propagation is governed not only by deviatoric stresses but also by pressure gradients and gravitational potential energy furthermore the model predicts the formation of curved dikes around cone shaped structures without the assumption of a local deviatoric stress eld we suggest that a likely eruption site for a laterally propagating dike is in topographic lows the method presented here is simple and computationally feasible our results indicate that this kind of a model can be applied to mitigate volcanic hazards in regions where the tectonic setting promotes formation of laterally propagating vertical intrusive sheets

all age depth models are wrong but how badly the uncertainty and error associated with fitted age depth models were investigated by fitting a range of models to sets of simulated radiocarbon dates based on varved sediments and comparing the modelled relationship with the varve timescale with large numbers of dates cubic smooth splines out perform other models with few dates no model reliably provides a good fit to reality and calculated confidence intervals are over optimistic c 2003 elsevier ltd all rights reserved

a 6000 yr varve record of holocene climate in saanich inlet british columbia from digital sediment colour analysis of odp leg 169s cores abstract high resolution grey value time series were extracted from digital images of varved sediments in saanich inlet british columbia odp sites 1033 and 1034 results allowed reconstruction of a 6000 yr long record with annual resolution composite records were compiled for sites 1033 and 1034 by correlation of massive beds which represent gravity flows and of characteristic features in the varve patterns the varve count age scale was calibrated with published radiocarbon ages results demonstrate that the odp leg 169s record is virtually complete saanich inlet varve record has the potential to provide a high resolution climate record temporal variation in varve thickness is interpreted to reflect regional precipitation history with thick varves representing wet conditions long term changes in varve thickness during the past 6000 yr coincide with known changes in global climate but without an obvious one to one correlation between wet dry in saanich inlet and warm cold periods elsewhere varve thickness indicates that the climate around saanich inlet was wet from the start of the varved sequence at 6000 to 3250 yr bp between 2100 and 1750 yr bp roman warm period and from 500 yr bp onward including during little ice age

holocene environmental and climatic change in the northern great plains as recorded in the geochemistry of sediments in pickerel lake south dakota the sediments in pickerel lake northeastern south dakota provide a continuous record of climatic and environmental change for the last 12000 yr sediments deposited between 12 and 6 ka radiocarbon show extreme variations in composition oxygen and carbon isotopic composition of bulk carbonate carbon isotopic composition of organic matter and magnetic susceptibility these variations re ect changes in sources of moisture regional vegetation types precipitation evaporation balance ground and surface water in ux water residence time erosion lake productivity water level and water temperature the total carbonate content of late pleistocene sediments steadily increased from 20 at the base of the core to as much as 80 in sediments deposited between 11 and 9 ka by about 8 ka the total carbonate content of the sediments had declined to about 40 where it remained with little variation for the past 8 kyr suggesting relatively stable conditions there are marked increases in values of d13c and d18 oi n bulk carbonate and d13c of organic matter in sediments deposited between 10 and 6 ka as evaporation increased and the vegetation in the watershed changed from forest to prairie this shift toward more 18o enriched carbonate may also re ect a change in source or seasonality of precipitation during this early holocene interval the organic carbon oc content of the sediments remained relatively low 2 3 but then increased rapidly to 4 5 between 7 and 6 ka re ecting the rapid transition to a prairie lake the oc content uctuates slightly between 4 and 6 in sediments deposited over the past 6 kyr like oc and total carbonate most variables measured show little variation in the 13 m of sediment deposited over the past 6 kyr particularly when compared with early holocene variations although the magnetic susceptibility of this upper 13 m of sediment is generally low 10 si units the upper six meters of the section is marked by striking 1 m cycles ca 400 500 yr periodicity in susceptibility these cycles are interpreted as being due to variations in the in ux of eolian detrital clastic material century scale cyclic variations in di erent proxy variables for aridity and eolian activity from sediments deposited over the past 2000 yr in other lakes in the northern great plains as well as in sand dune activity suggest that aridity cycles were the dominant feature of late holocene climate of the northern great plains 2000 elsevier

southward migration of the intertropical convergence zone through the holocene titanium and iron concentration data from the anoxic cariaco basin off the venezuelan coast can be used to infer variations in the hydrological cycle over northern south america during the past 14 000 years with subdecadal resolution following a dry younger dryas a period of increased precipitation and riverine discharge occurred during the holocene thermal maximum since approximately 5400 years ago a trend toward drier conditions is evident from the data with high amplitude fluctuations and precipitation minima during the time interval 3800 to 2800 years ago and during the little ice age these regional changes in precipitation are best explained by shifts in the mean latitude of the atlantic intertropical convergence zone itcz potentially driven by pacific based climate variability the cariaco basin record exhibits strong correlations with climate records from distant regions including the high latitude northern hemisphere providing evidence for global teleconnections among regional climates

chronology of the palmer deep site antarctic peninsula a holocene palaeoenvironmental reference for the circum antarctic palmer deep sediment cores are used to produce the first high resolution continuous late pleistocene to holocene time series from the antarctic marine system the sedimentary record is dated using accelerator mass spectrometer radiocarbon methods on acid insoluble organic matter and foraminiferal calcite fifty four radiocarbon analyses are utilized in the dating which provides a calibrated timescale back to 13 ka bp reliability of resultant ages on organic matter is assured because duplicates produce a standard deviation from the surface age of less than laboratory error i e 50 years in addition surface organic matter ages at the site are in excellent agreement with living calcite ages at the accepted reservoir age of 1260 years for the antarctic peninsula spectral analyses of the magnetic susceptibility record against the age model reveal unusually strong periodicity in the 400 200 and 50 70 year frequency bands similar to other high resolution records from the holocene but so far unique f

using pca to characterize and differentiate loess deposits in wisconsin and upper michigan usa abstract data on loess thickness as well as a variety of particle size fractions were determined for 875 samples taken from several loess sheets across wisconsin and upper michigan because the particle size characteristics of these samples varied widely within and between the loess sheets we used principal components analysis pca as a way of isolating the major textural components or signals that exist across the various loess sheets the purpose of this research was to examine and interpret these principal components or particle size signatures common to the different loesses in order to better understand the loess sheets character formation mechanisms and likely sources our initial assumption that many of these loesses varied markedly from the classical silty loess was supported by the particle size data and the pca although component 1 was interpreted as thick silty loess dominated by medium silts component 2 was mainly composed of very fine sand and coarse silt and is better viewed as coarse loess components 3 and 4 were less texturally homogeneous and may reflect mixing between the loess and the underlying sediment especially where the loess is

holocene tree line and climate change on the queen charlotte islands canada palynological study of two subalpine ponds on the queen charlotte islands reveals changes in tree line and climate during the holocene the findings agree with previous reconstructions from nearby louise pond on the queen charlotte islands that suggest a warmer than present climate and higher than present tree lines in the early holocene ca 9600 660014c yr b p basal ages at sc1 pond and shangri la bog indicate that the basins did not hold permanent water before 720014c yr b p consistent with a warmer and drier early holocene previously inferred from louise pond pollen and plant macrofossils indicate the initial establishment of subalpine conditions by 6090 9014c yr b p similar to the 5790 13014c yr b p age for cooling inferred from louise pond conditions similar to present were established at sc1 pond by 3460 10014c yr b p confirming the previous estimate of 340014c yr b p at louise pond this 340014c yr b p vegetation shift on the queen charlotte islands corresponds with the beginning of the tiedemann glacial advance in the south coastal mountains of british columbia ca 330014c yr b p the peyto and robson glacial advances between 3300 and 280014c yr b p in the rocky mountains and climatic cooling inferred from palynological studies throughout southern british columbia northern washington and southeast alaska these findings confirm that changes in regional climate influenced changes in vegetation in coastal british columbia

the impact of air mass circulation dynamics on late holocene paleoclimate in northwestern north america paleoclimate records from northern british columbia southwestern yukon and adjacent alaska suggest that late holocene climate may have been influenced by specific air mass circulation dynamics the aleutian lowpressure index alpi is a measure of sea level pressure fluctuations in the pacific northwest associated with the aleutian low al pressure system in this study we show that the al has a strong influence on historical climate change in the study area and explore the relationships between alpi polarity and changes in late holocene paleoclimate records analyses of weather station data in the study area indicate positive correlations r 0 63 between mean wintertime december march temperature and alpi values total wintertime snowfall accumulation and total precipitation show moderate and weak negative correlations respectively a late holocene increase in exotic western hemlock tsuga heterophylla pollen has been observed in regional paleoclimate studies a sustained positive alpi phase during the late holocene is considered as a causative mechanism under such conditions warm maritime air masses would more frequently penetrate inland potentially resulting in eastward pollen transfer enhanced growing conditions at coastal sites and an increase eastwards in the range limit of these species this study indicates that apparent conflicts in the timing and magnitude of late holocene climate change may be the result of a strong regional climate forcing mechanism that exhibits both temporal and geographical variation r 2002 elsevier science ltd and inqua all rights reserved