airborne dust and its significance to soils abstract movement of mineral dust by the atmosphere has been underway for ages but efforts to assess its magnitude and significance have come largely in the last century attempts to identify and understand effects of the dust on soils are even more recent mostly in the last 30 years airborne movements have several forms dust is transported by large storms that can be spectacular dust is also moved by smaller pulses and in a rather continuous flux most movement is within continents or from continents to nearby oceans but fine dust fine silt and clay is carried from one continent to another prime sources of the dust are the deserts and semi arid regions of the world for example large quantities of dust are carried out of the sahara every year quantities of dust carried by individual pulses from the small ones to the massive storms extend from a few thousand to 150 million metric tons during the course of a year the total quantities can be large one example is an estimate that on the average 770 million metric tons originating in the western united states are carried 2300 km each year that amount would add roughly 3000 kg ha 1 yr 1 to soils between the rocky mountains and the mississippi river small pulses and the near continuous flux add between 100 and 200 kg ha 1 yr 1 to soils of the eastern united states on the average comparable quantities are being added to soils in other parts of the world as well airborne accessions of dust have a variety of effects in soil development and on soils after they have been formed dust dominates processes of genesis in a few soils affects horizon differentiation appreciably in many more is a primary source of constituents essential to some horizons and layers in a number of soils provides the bulk of the material for silty surface horizons in many soils and can contribute supplies of nutrient elements for plants examples of all such effects are covered in this review first among these effects to be recognized even though not understood were the silty surface layers that failed to match underlying horizons later recognized was airborne dust as a source of calcium carbonate for calcic horizons that the dust could add significant quantities of nutrient elements as for example south of the sahara came into the picture even later the beneficial effects of airborne dust to many soils raises an interesting question is the dust more or less useful in its new location than it was in its source area an adequate answer to that question would provide an improved basis for assessing the effects of wind erosion

a revised model for the pleistocene development of the river avon warwickshire a re examination of the pleistocene river deposits in the valley of the midland avon indicates that the conventional post hoxnian model for their development has to be revised reinvestigation of two key localities cropthorne in the lower avon valley and ailstone on the warwickshire stour a left bank tributary of the avon shows that the deposits of at least two separate temperate episodes are represented within the sequence amino acid ratios on non marine mollusca from the temperate deposits allow these episodes to be correlated with oxygen isotope stages 5 and 7 since the stage 7 temperate deposit lies within sediments which post date the wolston glacial sequence an older age is indicated for that sequence than is proposed in the conventional stratigraphic succession of the british pleistocene

tree ring evidence of the widespread effects of explosive volcanic eruptions tree ring evidence from 97 sites over north america and europe are used to develop a chronology of widespread cool summers since 1600 averaging annual maximum density information from the chronologies provides an index that correlates with northern hemisphere summer temperatures to 0 44 over 1851 1975 a number of the extreme low density years occur in both north america and europe suggesting a common response to high frequency forcing the analysis was repeated with ring width information but the results are markedly less coherent of the five common extreme low density years 1601 1641 1669 1699 and 1912 four are known to be coincident with the year or year following major volcanic eruptions other extreme low density indices in the continental series are also clear coincident with known volcanoes the density indices clearly demonstrate great potential for quantifying the climate effectiveness and perhaps establishing precise calendar dates of large explosive volcanoes 30 refs

robotic micromilling of tree rings a new tool for obtaining subseasonal environmental isotope records high resolution intra ring 18 o d and 13 c values of modern tree species picea glauca larix laricina and populus grandidentata were obtained using a robotic micromill the micromilling apparatus permits accurate mapping and sampling of growth bands at a resolution of a few m producing a fine homogenous powder that facilitates chemical processing and analyses of very small aliquots of cellulose and cellulose nitrate 100 g considerable intra ring isotope variability observed in tree samples in this study correlates with temperature and precipitation data indicating that intra ring variability in 18 o 13 c and d has great potential for reconstructing high resolution variation in meteorological

spatial expression of enso drought and summer monsoon in seasonal δ13c of ponderosa pine tree rings in southern arizona and new mexico 1 major climatic impacts from enso and the north american monsoon in the u s southwest provide fortuitous circumstances for exploring the suitability of stable carbon isotope 13c composition of tree rings to represent and reconstruct interannual climate variability we sampled ponderosa pine tree rings at eight sites in seven mountain ranges over a 500 km transect in southern arizona and new mexico we developed 13c chronologies for 1985 1995 by subdividing rings into pre and post monsoon onset segments based on the presence of a false latewood band in each ring induced by the arid period immediately preceding the summer monsoon pooling these segments from multiple trees at each site and analyzing the cellulose component chronologies from two subsets of trees from the same site and separate chronologies from two different sites in the same mountain range indicate strong coherence and signal reproducibility additionally the seasonal 13c patterns showed remarkable coherence across the transect with the spatially disjunct easternmost chronology tending to be most frequently dissimilar the 13c values of ring subdivisions before the false latewood band are generally positively correlated with winter southern oscillation indices soi resulting from the enso teleconnection with southwestern winter early spring precipitation the 13c from these sites correlates with monthly palmer drought severity indices pdsi with the strongest correlations occurring in progressively later months from first formed to last formed subdivisions the post false latewood subdivision 13c was particularly strongly correlated with summer precipitation amount these results confirm the strong influence of moisture on tree ring 13c and support their use in both temporal and spatial modes to infer past climate variability

reconstructed summer degree days in central alaska and northwestern canada since 1524 abstract three time series based on precisely dated annual tree ring widths have been used to reconstruct june plus july degree days for the central alaska and northwestern canada region the time series are the longest recently developed chronologies for the area and represent 57 core samples from 27 trees the degree day reconstruction extending back to a d 1524 exhibits much year to year variation and extended warming and cooling trends including a general warming trend from about 1840 to 1960 the reconstruction is in agreement with some subaretic glacial information and with data of percentage melting from arctic ice cores this and similar reconstructions can provide quantitative information to compare with general circulation and energy budget models for longer time periods than are available in recorded meteorological data

oxygen isotopes in tree rings of abies alba the climatic significance of interdecadal variations we determined the 18o variations in the latewood of tree rings from four silver firs abies alba mill for the period 1840 1997 at a mountain site in switzerland establishing the longest available tree ring record for 18o in central europe the isotope ratios were determined on whole wood with a rapid continuous flow pyrolysis technique thus avoiding cellulose extraction we found significant correlations with 18o tree ring records from the same region although these involved different materials cellulose extracted from whole rings rather than latewood and different species this indicates that physical factors are more important than biological influences as a determinant of 18o in tree rings the isotope tree ring chronology was highly correlated with the oxygen isotope variations in the june july precipitation for the period 1972 1992 r 0 72 and 18o in whole wood of tree rings is therefore well suited for the reconstruction of 18o in precipitation we found a slow quasi periodic variation of the 18o series with a periodicity of 24 years which is correlated to variations in the july temperature this could be caused by fluctuations in the large scale atmospheric circulation over europe and the north atlantic which may result in a change in source and flow path of atmospheric moisture affecting the isotope ratio of precipitation in switzerland although a significant correlation with summer temperature was found p 0 01 the low correlation coefficient r 0 31 indicates that the 18o variations cannot be explained by temperature variations alone however even when considering that the factors influencing 18o in precipitation are not yet fully understood our study shows the potential of tree rings to provide long records of 18o in precipitation for continental areas which will improve our understanding of the causes of natural perturbations of the climate system

a latest cretaceous hotspot and the southeasterly tilt of britain the southeasterly regional dip of england and wales is usually ascribed to miocene movements loss of up to 2 km of cover from northern england shown by apatite fission track analysis has been related to uplift and erosion induced by a mantle hotspot but its effects were far more widespread than considered hitherto outcrop patterns throughout much of england wales and eastern ireland can be related to a hotspot beneath the irish sea uplift occurred within the late maastrichtian and erosion continued into the late palaeogene after post oligocene down faulting of the irish sea the modern drainage was initiated on the eroded surface unconformities provide the best means of dating orogenic movements in some localities the time interval between the youngest rocks preserved beneath the unconformity and the oldest preserved above may be small enough to enable the dating of fold movements to be determined with some precision thus in southeastern britain the major e w structures of the hampshire basin the weald and the london basin can be dated as miocene as rocks of oligocene age are involved in the folding in the hampshire basin and pliocene sands rest in erosional pockets of the chalk of se england because fold movements tend to affect large areas of the crust at discrete intervals of time the southeasterly tilt of britain evident from the fact that a nw se transect from anglesey to london crosses outcrops of rocks getting progressively younger from the precambrian of anglesey to the tertiary of the london basin has

climate signals in δ 13 c of wood lignin methoxyl groups from high elevation larch trees abstract in this study a barely used method to measure 13c values from lignin methoxyl groups 13cmethoxyl of tree rings is applied to high alpine larch trees to test their potential as a climate proxy thirty seven larch trees larix decidua mill were sampled at a tree line site near simplon village in the valais switzerland samples were used to measure tree ring width and from five individuals 13cmethoxyl was determined at annual resolution from 1971 to 2009 and at pentadal resolution from 1747 to 2009 the physiological tree responses to increasing atmospheric co2 concentration since 1850 and the corresponding decrease in 13c suess effect were corrected using a range of published discrimination factors and approaches one of these approaches considers a flexible correction factor which minimizes the residuals with target climate data testing the response of the new 13cmethoxyl proxy to climate revealed significant correlations with june to august temperatures ranging from r 0 56 to 0 75 for annually and from r 0 41 to 0 87 for pentadally resolved data depending on the correction methods tree ring width also shows significant correlations with june to august temperature these results demonstrate the potential of 13cmethoxyl to serve as a summer temperature proxy in high elevation alpine environments

thames river sediments of the british early and middle pleistocene abstract the thames drainage system contains the most complete record of fluvial sediments in the british quaternary the kesgrave sands and gravels form the main body of this sediment having been deposited over an interval that spans the later part of the early pleistocene and most of the middle pleistocene conventional stages pre pastonian a through to early anglian ca 1 2 ma this deposit provides a stratigraphic context for related bio morpho and pedostratigraphic evidence and for the recognition of pre anglian pre oi stage 12 upland glaciation in the welsh mountains and intense periglaciation in lowland england it also facilitates correlation with the stratigraphy of northern europe and the global pattern of orbitally forced climatic change this paper describes the first catchment wide correlation of thames river sediments and proposes a formal redefinition of the lithostratigraphic units concerned the scheme outlined here is based on two lithologically distinctive formations defined at type areas reflecting significant changes in catchment dimensions the earlier sudbury formation was formed when the thames catchment extended into wales and drained northwards across east anglia the later colchester formation was formed after the upper catchment had been reduced in extent to that of the present river but continued to flow across east anglia the whole sediment body is now named the kesgrave group

stability of climate signal in carbon and oxygen isotope records and ring width from scots pine pinus sylvestris l in finland four hundred year long records of carbon and oxygen stable isotope ratios and ring width were measured from scots pine pinus sylvestris l from sites in northern and eastern finland responses of isotope ratios to temperature and precipitation were analysed for the 20th century carbon isotope ratios responded strongly to summer temperature at both sites whereas an influence of precipitation on the record was observed only at the site in eastern finland oxygen isotope ratios were less responsive to climatic variation than carbon at the high frequency level to shed light on the role of the possible divergence problem during last decades the climate responses were studied separately in the first and in the second half of the 20th century the responses to temperature were stable in the north but in eastern finland the significant period of summer occurred earlier during the later half of the century relationships between records were studied during the 400 a period all proxies correlated positively with each other although temporal changes occurred common forcing discovered in northern finland between carbon isotope and ring width records was weaker in the earlier period studied three climate reconstructions were created temperature reconstruction for northern finland and temperature and precipitation reconstructions for eastern finland copyright 2009 john wiley sons ltd

comparison of stable carbon and oxygen isotopes in picea glauca tree rings and sphagnum fuscum moss remains from subarctic canada stable isotope ratios from tree rings and peatland mosses have become important proxies of past climate variations we here compare recent stable carbon and oxygen isotope ratios in cellulose of tr

δ13c δ15n n concentration and ca to al ratios of forest samples from pinus densiflora stands in rural and industrial areas abstract in an effort to evaluate the potential adequacy of carbon isotope ratio 13 c 12 c expressed as 13 c nitrogen isotope ratio 15 n 14 n expressed as 15 n n concentration and ca to al ratio of forest samples as proxies for atmospheric pollution samples of needle bark litter organic soil and inorganic soil were collected from red pine pinus densiflora stands located in industrial polluted and rural background and regarded as relatively unpolluted areas and their chemical and isotopic compositions were compared the 13 c of needles and bark samples from the industrial area were significantly p 13 c depleted co 2 emissions from fossil fuel combustion in industrial areas the 15 n of all the samples from the industrial area were significantly p 15 n depleted atmospheric n in the industrial areas however no significant differences were noted with regard to the total n concentrations of the samples from different areas this was probably due to different indigenous soil n availability with regard to ca to al ratios the needle samples had a significantly lower ca to al ratio in the industrial samples by approximately 17 to 43 probably as the result of enhanced soil acidification by acid deposition as compared with rural areas combining all the samples and isotopic and chemical variables the 13 c 15 n and ca to al ratios of the needle samples were identified as the most reliable proxies for atmospheric pollution in the study areas further study will be necessary to develop quantitative criteria for the practical use of each indicator in identifying forest ecosystems that are susceptible to atmospheric pollution

tortoises and hares dissolution erosion and isostasy in landscape evolution denudation mechanisms differ fundamentally between limestone and silicate rock types which are subject to very different rate thresholds and enhancers inhibitors silicates are removed largely by erosion the mechanical entrainment and transport of particles this is a relatively high energy and highly episodic process which occurs only when a minimum threshold flow velocity is exceeded it is inhibited by vegetation cover and favoured by strongly seasonal runoff limestone is removed largely by chemical dissolution at a rate directly proportional to runoff dissolution is a relatively low energy process that can occur at any flow velocity or in static water in general it is enhanced by vegetation cover and non seasonality of runoff these contrasting factors in the denudation of silicates versus limestone can produce strikingly uneven rates of surface lowering across a landscape sometimes akin to the well known tortoise and hare race where the slow and steady denudation of limestones may in the long term exceed the sometimes rapid but often localized and episodic erosion of silicates prolonged exposure of limestone to a humid temperate climate in a tectonically stable environment produces lowrelief corrosion plains in which limestone uplands are anomalous and in most instances due to recent unroofing from beneath a siliciclastic cover in a highly seasonal or semi arid climate almost the exact inverse may develop with flashy runoff and sparse vegetation favouring erosion rather than dissolution even under a constant humid climate progressive unroofing of a thick limestone unit within folded siliciclastics may lead to a topographic inversion over time with the limestone outcrop always forming a topographic low flanked by siliciclastic uplands valleys will be initiated on anticlinal crests where the limestone is first unroofed but progressive lowering of the limestone causes these valleys to migrate to their final position in the synclinal troughs in humid climates isostatic compensation in response to slow but continuous denudation of extensive limestone outcrops may be a significant factor in the development of relief on adjacent more slowly eroding silicate outcrops copyright 2004 john wiley sons ltd

evaluating the integrity of c and o isotopes in sub fossil wood from boreal lakes abstract extending climatic series back to the first millennium using isotopic tree ring chronologies in northern regions represents a challenge because trees seldom reach the adequate age fossil trees deposited in boreal lakes could serve such an endeavor provided that dating the tree ring series is possible and that the isotopic ratios of sub fossil wood are preserved from two boreal lakes in north eastern canada we collected segments of picea mariana black spruce stems with different degrees of wood textural preservation and covering the last millennium our main objectives are to assess the selection criteria for wood textures suitable for isotopic reconstruction and verify the reliability of sub fossil cellulose carbon and oxygen isotopic series for climatic reconstruction in boreal regions the isotopic differences between cellulose and lignin obtained for 48 ring pairs of a living tree 13cc l 3 7 0 3 18oc l 13 1 and 46 contemporaneous pairs from a sub fossil stem 3 5 0 3 and 12 9 0 9 in the same order are systematic and matching for the selection of all sub fossil samples we have visually identified three main classes of wood textures for which the degree of alteration is confirmed by secondary electron microscopy well preserved slightly altered and highly altered slightly altered stem segments have cellulose proportion showing a relative decrease reaching 35 but 13cc l and 18oc l values within the range of living trees non altered sub fossil stems covering the 14th and 11th centuries show systematic and coherent 13cc l 3 5 0 2 3 8 0 4 and 18oc l results 13 9 0 7 13 5 0 5 highly altered wood shows a decrease in both cellulose proportion and 18ocellulose values but apparently preserved 13c ratios this research shows that it is possible to visually identify the degree of wood preservation and preselect sub fossil segments holding reliable isotope ratios and to use sub fossil stems collected from boreal lake floors to reconstruct climate over the last millennia

tree rings δ13c and climate in picea glauca growing near churchill subarctic manitoba canada abstract white spruce picea glauca moench voss trees were sampled to investigate the relationship between ring width and 13c as well as between these descriptors and climate cross sections from eight white spruce trees growing in the hudson bay lowlands subartic manitoba with an establishment date prior to 1775 were selected from our archive for each cross section two radii were measured to produce ring width chronologies for stable carbon isotope measurements every fifth ring 2000 1995 1750 was analyzed separately from each tree whereas approximately equal masses from the eight trees were pooled into composite samples for each of the intermediate years mixing masses from each tree equal to that from the tree with the least amount alpha cellulose was extracted and 13c was determined using continuous flow mass spectrometry the ring width residual chronology derived from eight trees was highly correlated to that previously developed for the area a small but significant correlation was also found between the ring width and the 13c residual chronologies the climate signal contained in both ring width and the 13c residual chronologies suggests that warm early summers were conducive to larger rings whereas the 13c best reflects the overall growing season temperature precipitation relative humidity and or drought index have little to no association with either chronology significant correlations were observed between 13c and the historical ice records from the hudson bay co archive data suggesting that during long warm growing season the 13c content of alpha cellulose increases our results indicate that both ring width and 13c provide complementary information future work will involve looking at long term trends in carbon isotope ratios and the potential use of 13c for dendroclimatic reconstruction

lithospheric flexure uplift and landscape evolution in south central england the high level river gravels in oxfordshire the northern drift group which range in age from early pleistocene to around 450 ka contain pebbles that were derived from a source area to the north near birmingham the pebbles could not have been transported across the upper triassic and lower jurassic clay outcrops of the midlands unless the region was at or close to sea level the present day cotswold escarpment ranges from 70 to 215 m this uplift must therefore have occurred after deposition of the northern drift group when the drainage of the midlands appears to have shifted from towards the thames basin to the bristol channel area it is concluded that lithospheric flexure due to the removal of 500 km 3 of soft late triassic and early jurassic clays and marls from large areas of the midlands and their re deposition in the celtic deep might account for this late pleistocene uplift uplift in the midlands is the likely explanation for both the tilted approximately 0 3 plateau surface in north oxfordshire and the change in strike of the jurassic beds sw of northamptonshire although some uplift occurred in se england during the early cenozoic and miocene we demonstrate here that there has been significant uplift of the region in the late pleistocene the tilted plateau surface in north oxfordshire may therefore be a relatively young i e post 450 ka feature related to tectonic uplift in the midlands

impact of recent north atlantic anomalies on surrounding land areas based on dendroclimatic evidence tree rings are useful indicators of interannual to decadal scale climate variability in this paper we show that tree ring data from the northwestern atlantic sector may reflect the great negative salinity gsa and related positive sea ice anomalies of the 1960 s 70 s along with cold surface air temperatures at coastal land stations there were declines in ring widths in the 1970 s in temperature sensitive birch trees in southern greenland white spruce in labrador and white spruce and white pine from newfoundland tree ring and other data from both sides of the north atlantic also indicate a decadal scale warm event with subsequent cooling around the 1820 s 1830 s

assessing tree ring carbon and oxygen stable isotopes for climate reconstruction in the canadian northeastern boreal forest abstract in this study we analyzed stable isotopes of oxygen 18o and carbon 13c of five black spruce picea mariana mill bsp trees growing in the quebec boreal forest we then produced the first dendroisotopic series covering the last two centuries 1800 2003 for this region where climatic records are particularly scarce and of short duration our aim was to evaluate the isotope sensitivity to climate and their potential as proxies for past climate conditions the 18o results show a strong coherence between all trees indicating that these values express a homogenous response at the site scale for the 13c series slight inter tree differences suggest the influence of micro site conditions isotopic values were compared to climatic data for the period 1944 2003 these statistical analyses indicate that the 13c and 18o ratios are directly influenced by summer maximum temperatures but also correlate with parameters that integrate temperatures and moisture status in all cases the climate effects on 13c values are weaker than the ones recorded by the 18o series moreover because the 18o and 13c values are sensitive to climatic variables that are linked and commonly associated in typical subarctic climate ambiances warm dry cold wet the patterns of their joint response show stronger correlations with climatic parameters then a temperature reconstruction was developed based on a regression model that calibrates the combined 13c and 18o series against summer maximum temperature tmaxjja the reconstructed summer temperatures indicates that the first half of the 19th century was the coldest period in the past 200 years and that a steadily change throughout milder conditions started in the early 1940 s these trends are consistent with other reconstructed values from independent proxies available for the same region this research confirms that c and o dendroisotopic series of black spruce trees in high latitudes can document adequately past climatic conditions

reducing uncertainties in δ13c analysis of tree rings pooling milling and cellulose extraction recent developments of on line methods have provided another boost to the determination of stable isotope ratios in organic material along with a significant increase in sample throughput the sample sizes decrease both of which are necessary conditions to acquire long time series from limited wood amounts in view of this new technique we reconsidered the most important factors influencing the measured isotopic signature which are 1 pooling 2 homogeneity and 3 cellulose extraction in most cases pooling i e mixing wood of the same year from different trees can be made in a simple way by mixing the whole wood available because mass weighted and unweighted isotope measurements were the same within the error more attention must be paid in homogenizing the sample theoretical considerations underpinned by experimental results suggest a fineness of 0 15 mm 115 mesh if cellulose is extracted and 0 1 mm 165 mesh for direct wood analysis many of previous studies did not achieve this fineness we find that wood is as good a climate proxy as cellulose this is shown by comparing correlations of wood and corresponding cellulose isotope values with meteorological data which are identical within the uncertainty

transformations of 2 1 phyllosilicates in 41 year old soils under oak and pine abstract the large unconfined lysimeters at the san dimas experimental forest in southern california provide a unique setting in which to study decade scale vegetation effects on mineral weathering we investigated the 2 1 phyllosilicate mineralogy of lysimeter soils under 41 year old monocultures of scrub oak quercus dumosa nutt and coulter pine pinus coulteri b don and compared the results to archived original fill material x ray diffraction showed that mica increased relative to vermiculite in the clay and medium silt fractions of a horizons under both oak and pine compared to the archived original fill material the increase however was far greater under oak than under pine no mineralogical differences were observed in the subsurface horizons of either oak or pine compared to archived material nonexchangeable k increased by 23 in the clay fraction of the oak a horizon and increased by 5 in the clay fraction of the a horizons under pine relative to archived parent material strong evidence supports biocycling as the basis for observed decade scale mineral transformations we conclude that the return of k to the soil surface through litter decomposition and subsequent fixation by vermiculite resulted in increased mica contents in a horizons more k may have been fixed by vermiculite in the oak a horizon compared to pine due to greater k concentration in the oak litter pool earthworm mediated mineralization of k from organic matter under oak and presence of fewer roots at the surface under oak and consequently less plant removal of k from the a horizon

incipient weathering by stereocaulon vulcani at reunion volcanic island abstract the impact of early land plants and fungi in increasing global weathering is still debated particularly before the advent of vascular plants during the devonian here we present a study of the incipient weathering of basalt by stereocaulon vulcani a native colonizing lichen on reunion island indian ocean we analyzed the chemistry and mineralogy of a 24 year old flow located at low altitude that was mostly covered by s vulcani with aboveground biomass of 6249 kg ha 1 the chemical composition of s vulcani showed that besides c and n si and fe were the dominant elements the si stored in the aboveground pioneer vegetation gives 27 kg ha 1 comparable to the si stored in the old growth at the marelongue reserve meunier et al 2010 on thin sections the inner part of s vulcani was mostly composed of si while fe coatings observed at the base of the thallus may be the result of wind blow dust interception as suggested by cochran and berner 1992 using bse images on sem we showed evidence of dissolution of the glass matrix at the basalt thallus contact the quantification of porosity by digital imagery showed a variation between 7 in the unweathered zone to near to 40 at the surface a maximum denudation rate of 6 7 m year 1 is estimated to fall within the range of the values reported in the literature using our data for analog to the past we suggest that early land plants would have been capable to mobilize si in a similar proportion as vascular plants and should have significantly affected the weathering of land before the advent of vascular plants

long term climate variability in continental subarctic canada a 6200 year record derived from stable isotopes in peat the rapid warming of arctic regions during recent decades has been recorded by instrumental monitoring but the natural climate variability in the past is still sparsely reconstructed across many a

temperature and air pollution affected tree ring δ13c and water use efficiency of pine and oak trees under rising co2 in a humid temperate forest abstract to better predict forest productivity under rising atmospheric co 2 concentration co 2 it is critical to understand how intrinsic water use efficiency wue i and its relationship with tree growth are affected by the concomitant changes in environmental conditions such as precipitation temperature and air pollution that either enhance or undermine any potential co 2 fertilization effect we investigated changes in 13 c and wue i in annual rings and basal area increment bai of pinus densiflora from 1968 to 2007 and quercus variabilis from 1970 to 2007 trees in relation to precipitation temperature and air pollution in a humid temperate forest the wue i of p densiflora increased by 39 9 whereas that of q variabilis did not change over time in the study period the wue i was not affected by precipitation for both species but increased p p densiflora and with so 2 emissions for both species multiple regression models suggested that the effect of co 2 on tree growth was much higher than temperature however for the period 1998 to 2007 when so 2 emissions data were available so 2 emission was the driver of changes in bai and wue i and temperature effects became stronger than co 2 overall bai and wue i were positively p p densiflora but not for q variabilis we conclude that temperature and air pollution rather than precipitation were key determinants of wue i at the study site and that the two species had contrasting responses to environmental changes

stable carbon isotopes from tornetrask northern sweden provide a millennial length reconstruction of summer sunshine and its relationship to arctic circulation this paper presents results from the first 1100 years of a long stable carbon isotope chronology currently in development from scots pine pinus sylvestris l trees growing in the tornetrask region of northern sweden the isotope record currently comprises a total of 74 trees with a mean annual replication of 12 thereby enabling it to be compared directly with other tree ring based palaeoclimate reconstructions from this region in developing the reconstruction several key topics in isotope dendroclimatology chronology construction replication co2 adjustment and age trends were addressed the resulting carbon isotope series is calibrated against instrumental data from the closest meteorological station at abisko ad1913 2008 to provide a record of june august sunshine for northern fennoscandia this parameter is closely linked to the direct control of assimilation rate photosynthetically active radiation par and the indirect measures mean july august temperature and percent cloud cover the coupled response of summer sunshine and temperature in this region permits a multiparameter comparison with a local reconstruction of past temperature variability based upon tree growth proxies to explore the stability of this coupling through time several periods are identified where the temperature x ray density and sunshine stable carbon isotope ratio records diverge the most significant and sustained of these occur between c ad1200 1380 and c ad1550 1780 providing evidence for a cool sunny two phase little ice age whilst summer sunshine reconstructed for the 20th century is significantly different from the mean of the last 1100 years p 0 01 so it is the 17th 18th and to a lesser extent the 13th centuries rather than the early medival period that appear anomalous when viewed within the context of the last 1100 years the observed departures between temperature and sunshine are interpreted as indicating a change in large scale circulation associated with a southward migration of the polar front such a change affecting the northern annular mode arctic oscillation would result in more stable anticyclonic conditions cool bright summers over northern fennoscandia thus providing a testable mechanism for the development of a multi phase time transgressive little ice age across europe

discussion on lithospheric flexure uplift and landscape evolution in south central england journal vol 157 2000 1169 1177 scientific editing by alex maltman j c w cope writes the paper by watts et al contains interesting ideas on landscape evolution but by concentrating their observations locally and by overestimating post anglian erosion they may have lost sight of more widespread effects that could have been major contributors to the features they describe and thus their causative mechanisms may need re examination cope 1994 suggested that uplift centred in the irish sea explained the loss of 2 km of mesozoic cover there explaining apatite fission track analyses from the eastern irish sea and northwestern england the southeasterly regional dip of the mesozoic outcrop of the english midlands could be attributed to this uplift although a mantle plume was suggested as the cause the same effect could be attributed to mantle underplating substantial igneous activity is known around the irish sea region before the earliest antrim basalts the fleetwood dyke in the eastern irish sea is dated at 65 5 ma arter fagin 1993 and similar ages are known from dykes in north wales evans et al 1973 pre basalt dykes exist in northern ireland whence simms 2000 records dykes cutting chalk and truncated by the basal palaeogene lavas cope s 1994 reconstruction of the missing mesozoic cover of the area from the cheshire basin southwards led him to suggest that the resultant average gradient imparted over the midlands from the cheshire basin to the chiltern scarp was 1 87 5 what was incorrectly calculated from this figure by cope 1994 was the angle of dip represented by that figure which is 0 7 and not 2 the former is close to that recorded by watts et al for the area of oxfordshire they considered and this suggests that they may have overestimated the uplift caused by lithospheric flexuring there may be

localized quaternary uplift of south central england the early quaternary of south central england is characterized by uplift as is indicated by the river gravels that extend intermittently from oxfordshire through northamptonshire to lincolnshire the earliest of these gravels contain abundant quartz and quartzite clasts derived from lower triassic conglomerates in the west midlands but later deposits contain progressively larger amounts of locally derived jurassic sediments this compositional change is associated with the incision of the rivers that flowed eastwards from the west midlands subsequently the headwaters of some of these rivers were diverted towards the bristol channel and their suspended material was deposited on the outer parts of the uk continental shelf and slope the area of incised drainage gloucestershire to lincolnshire did not extend to east anglia in the east or to somerset in the west both these coastal regions contain several marine horizons showing that the area of uplift did not include the whole of southern england the uplift cannot therefore be attributed to eustatic changes in sea level the area of uplift is centred on the broad topographic depression of the english midlands and corresponds approximately to the outcrop of thick c 1 km upper triassic and lower jurassic mudrocks we have used an ordnance survey 50 m 50 m topographic grid to estimate the amount of mudrocks that has been removed from the depression and 2d flexural unloading models to calculate the tectonic uplift that resulted for various assumptions of the effective elastic thickness which is determined by the flexural rigidity of the lithosphere the amount of material removed is in accord with what is known of the volume of quaternary deposits offshore and the uplift accounts for the incised plateau surfaces of the flanking cotswold hills and the high ground of northamptonshire to the east and the forest of dean and the hills of herefordshire to the west

reconstruction of past ice conditions in a hudson bay estuary using tree rings descriptions of ice conditions ranging from lake and sea ice to glacial advances and retreats form an important portion of the climatic record ice formation deterioration and changing areal extent are of increasing interest in climatology sea transportation petroleum exploration and the fishing industry with few exceptions quantitative information on ice conditions is generally brief with many records in the us and canada beginning only in the 1950s1 tree ring data from long lived trees can be used as quantitative proxy data for past climatically related parameters the record of first complete freezing of the churchill river estuary on hudson bay is reconstructed here for 298 yr 1680 1977 by means of tree ring analysis

discussion on lithospheric flexure uplift and landscape evolution in south central england scientific editing by alex maltman j c w cope writes the paper by watts et al contains interesting ideas on landscape evolution but by concentrating their observations locally and by overestimating post anglian erosion they may have lost sight of more widespread effects that could have been major contributors to the features they describe and thus their causative mechanisms may need re examination cope 1994 suggested that uplift centred in the irish sea explained the loss of 2 km of mesozoic cover there explaining apatite fission track analyses from the eastern irish sea and northwestern england the southeasterly regional dip of the mesozoic outcrop of the english midlands could be attributed to this uplift although a mantle plume was suggested as the cause the same effect could be attributed to mantle underplating substantial igneous activity is known around the irish sea region before the earliest antrim basalts the fleetwood dyke in the eastern irish sea is dated at 65 5 ma arter fagin 1993 and similar ages are known from dykes in north wales evans et al 1973 pre basalt dykes exist in northern ireland whence simms 2000 records dykes cutting chalk and truncated by the basal palaeogene lavas cope s 1994 reconstruction of the missing mesozoic cover of the area from the cheshire basin southwards led him to suggest that the resultant average gradient imparted over the midlands from the cheshire basin to the chiltern scarp was 1 87 5 what was incorrectly calculated from this figure by cope 1994 was the angle of dip represented by that figure which is 0 7 and not 2 the former is close to that recorded by watts et al for the area of oxfordshire they considered and this suggests that they may have overestimated the uplift caused by lithospheric flexuring there may be

stable carbon and hydrogen isotope ratios of subfossil oaks in southern germany methodology and application to a composite record for the holocene the d ad values exist for the time interval 6470 bc to ad 905 not all records have the same time resolution and not all of them were prepared in the same way for isotope analysis however investigations on the influence of the preparation technique on the isotope values and on the isotope composition of different wood compartments latewood and earlywood respectively allowed us to homogenize the records the comparison of d values of wood with different cambial ages showed that hydrogen isotoperatios were affected by growth tre

the effect of site fertility and climate on current weathering in finnish forest soils results of a 10 16 year study using buried crushed test rock material abstract knowledge of the weathering rates in forest soils is needed when nutrient balances and the sustainability of silvicultural practices are estimated the effects of site fertility and climate on weathering rates were studied in boreal coniferous forest soils in finland by following transformations in crushed rock spectrolite a dark anorthosite feldspar dominated gabbro confined in porous bags inserted into e b and c horizons along fertility and climate gradients and left to weather for 10 11 or 16 years organic carbon oc was accumulated in e horizon incubated crushed test rock material and it was more acidified and weathered than that deeper in the soil there was a tendency for faster weathering of the c horizon bags in the fertile sites than in the poor sites multivariate analyses indicated that more oc was accumulated in the bags in fertile sites than in poor sites and that the crushed rock was more weathered in north than in south finland although temperature sum and precipitation decreased northwards the results suggest that humidity is an important climatic factor determining weathering rates and that fertile sites have greater potential to release base cations through weathering and sequester c to mineral surfaces than do poor sites

progress in isotope dendroclimatology numerous studies have demonstrated the potential of stableisotopes in tree rings for quantitative terrestrial palaeoclimaticreconstruction ramesh et al 1986 heaton 1999 switsur andwaterhouse 1998 mccarroll and loader 2004 2005 but the earlywidespread application of isotope dendroclimatology has been hin dered by laborious technical procedures that have until recently prevented wider application of this technique and severely con strained progress developments in mass spectrometry preston andowens 1985 barrie et al 1995 filot et al 2006 leuenberger andfilot 2007 and sample preparation techniques leavitt and danzer 1993 loader et al 1997 brendel et al 2000 schulze et al 2004 rinneet al 2005 gaudinskiet al 2005 haverevolutionisedthe eldand enabled development of stable isotope chronologies with aheightened degree of replication gagen et al 2007 and temporalrange treydteetal 2006 thatwaspreviouslynotpracticalandrarelyobserved in any other proxy record outside of dendroclimatology these and associated advances are re ected in the dramatic increasein the number and diversity of isotope tree ring papers presented atrecent international conferences the thirty isotope tree ring paperspresented at the recent 7th international conference on dendrochro nology beijing 11 17june2006 aretrulyinstarkcontrasttothetwodelivered at the 2nd international workshop on global dendroclima tology 1980 long 1982 wigley 1982 in this volume the progressand advances in isotope dendroclimatology are critically reviewed inthe context of the initial work and aspirations of the early pioneers inthis eld and new directions and methodologies are explored dendroclimatology is an established eld of palaeoclimatologyused in its scienti c form since the early 20th century however theapplication of stable isotope techniques to dendroclimatology is morerecent conceptually the seed was planted when urey 1947 statedthat it seems probable that plant carbon compounds synthesised atdifferent temperatures may contain varying amounts of c

uplift driven valley incision and river terrace formation in southern england outside the limits of middle pleistocene glaciation the river basins of southern england contain long cenozoic terrestrial sedimentary records of greatest importance are the river terrace sequences which contain biostratigraphical and sedimentary evidence that testifies to the high amplitude climatic changes of the quaternary however trends in valley development cannot easily be accommodated within the framework of quaternary climatic change it is argued in this paper that episodic incision and terrace development result from uplift a consequence of the interplay between continuing alpine orogenic movements and erosion driven isostasy using a simple linear model height age an uplift rate of ca 7 cm ka 1 is estimated for the terrace sequence in the upper thames valley this preliminary model is evaluated using the records of adjacent basins 1997 john wiley sons ltd

climate signals in tree ring width density and δ13c from larches in eastern siberia russia abstract we present the first and longest 413 years dataset on stable carbon isotope ratios in tree ring cellulose 13c tree ring width trw and maximum latewood density mxd obtained from larch trees growing on permafrost under continental climate in the suntar khayata mountain ridge in eastern siberia russia with this first study we calibrate tree ring parameters against climate quantities and based on these results assess the potential added value of mxd and especially of 13c complementing trw analysis for future climate reconstruction purposes 13c chronologies were corrected for human induced changes in atmospheric co2 since ad 1800 two different approaches were compared i a correction referring merely to the decline in atmospheric 13c 13catm and ii a correction additionally accounting for the increase in atmospheric partial pressure of co2 13c chronologies are characterized by strong signal strength with only 4 trees representing the population signal at the site mean inter series correlation 0 71 and eps 0 90 13c variation shows low similarity to trw and mxd while correlation between trw and mxd is highly significant correlation analysis of tree ring parameters with gridded instrumental data climate research unit cru ts 2 1 over the ad 1929 2000 calibration period demonstrates that trw and mxd react as reported from other sites at cold and humid northern latitudes precipitation plays no significant role but strong dependencies on monthly mean maximum and minimum temperatures particularly of the current summer june to august are found up to r 0 60 p

later pleistocene evolution of the exe valley a chronstratigraphic model of terrace formation and its implications for palaeolithic archaeology this paper presents the first systematic chronostratigraphic study of the river terraces of the exe catchment in south west england and a new conceptual model for terrace formation in unglaciated basins with applicability to terrace staircase sequences elsewhere the exe catchment lay beyond the maximum extent of pleistocene ice sheets and the drainage pattern evolved from the tertiary to the middle pleistocene by which time the major valley systems were in place and downcutting began to create a staircase of strath terraces the higher terraces 8 6 typically exhibit altitudinal overlap or appear to be draped over the landscape whilst the middle terraces show greater altitudinal separation and the lowest terraces are of a cut and fill form the terrace deposits investigated in this study were deposited in cold phases of the glacial interglacial milankovitch climatic cycles with the lowest four being deposited in the devensian marine isotope stages mis 4 2 a new cascade process response model is proposed of basin terrace evolution in the exe valley which emphasises the role of lateral erosion in the creation of strath terraces and the reworking of inherited resistant lithological components down through the staircase the resultant emergent valley topography and the reworking of artefacts along with gravel clasts have important implications for the dating of hominin presence and the local landscapes they inhabited whilst the terrace chronology suggested here is still not as detailed as that for the thames or the solent system it does indicate a middle palaeolithic hominin presence in the region probably prior to the late wolstonian complex or mis 6 this supports existing data from cave sites in south west england

a 500 year record of summer near ground solar radiation from tree ring stable carbon isotopes tree ring stable carbon isotope ratios d13c in environments of low moisture stress are likely to be controlled primarily by photosynthetic rate therefore sunshine rather than temperature represents the more direct controlling factor temperature reconstructions based on tree ring d13c results thus rest on the assumption that temperature and sunshine are strongly coupled this assumption is tested using a d13c series from pine trees in nw norway where there are long 100 yr records of both summer temperature and cloud cover it is demonstrated that when summer temperature and d13c diverge summer temperature and cloud cover also diverge and that cloud cover sunshine may provide a stronger and more consistent parameter with which to calibrate tree ring d13c series in this area when a 500 year reconstruction of summer cloudiness is compared with a published reconstruction of summer temperatures in northern sweden based on tree ring maximum densities the two time series are largely parallel with

pleistocene geology of the lower severn valley u k abstract the lower severn valley contains a sequence of fluvial glaciofluvial and glaciogenic deposits of pleistocene age which is divided into two formations glaciogenic sediments are correlated with members of the wolston formation anglian a new formation the severn valley formation which consists of fluvial deposits is defined it is sub divided into six members the four oldest of which are considered in this paper the oldest deposits in the lower severn basin are the till and glaciofluvial outwash gravels of the woolridge member the till is correlated with the thrussington member of the wolston formation which is correlated with the lowestoft formation of the anglian stage oxygen isotope stage 12 the oldest member of the severn valley formation the spring hill member is provisionally correlated with oi stage 10 the bushley green member represents deposition during oi stages 9 and 8 the basal fossiliferous sediments bushley green fossil bed are correlated with oi stage 9 by amino acid geochronology the kidderminster station member records a significant input of lithologies not seen in quantity in the higher members and evidence is presented which suggests that this is a response to renewed glaciation in the upper basin this glaciation was responsible for the deposition of the ridgacre formation of the birmingham area amino acid geochronology and chlorine 36 ages from erratic boulders show that the kidderminster station member and ridgacre formation are of oi stage 6 warthe age the basal deposits of the holt heath member include the stourbridge fossil bed with a temperate fauna believed to be ipswichian last interglacial oi substage 5e and the upton warren fossil bed oi substage 5a most of the holt heath member consists of outwash from an irish sea ice sheet which entered the severn basin during the late devensian oi stage 2

a 263 year record of summer temperature for northern quebec reconstructed from tree ring data and evidence of a major climatic shift in the early 1800 s abstract tree ring data are used to reconstruct 263 years of summer temperatures at a site located near the northern tree line in central western quebec a chronology comprising 20 ring density time series is used in conjunction with a chronology comprising 20 ring width time series in the regression analyses the increased precision of the temperature estimates obtained by using density data as an additional proxy time series places the reconstruction and its interpretation on a firmer basis than it is when only ring width data are used the results are considerably improved over the use of either tree ring parameter alone the temperature reconstruction reflects a major cooling event in the early nineteenth century comparisons with other temperature and proxy data series support the idea of a global cooling event with a persistence of the cool period of about three decades in high latitude north america and of much shorter duration in other regions of the world volcanic activity in the early 1800 s is suggested as partially responsible for the cooling event but is considered inadequate as cause for the extended period of low temperatures in the locale of this reconstruction

stable carbon isotope ratios of pinus sylvestris from northern finland and the potential for extracting a climate signal from long fennoscandian chronologies stable carbon isotope ratios were measured on the latewood cellulose of 36 scots pine trees from four sites in northern finland 13c values were corrected for changes in the 13c of air and de trended to remove the effect of tree age simple linear and multivariate correlations were used to determine the nature and strength of any climate signal at three sites the dominant controls are in descending order summer sunshine temperature and antecedent precipitation at the fourth site the dominant controls are antecedent precipitation and air relative humidity while summer sunshine and temperature appear unimportant 13c values record changes in the concentration of co2 in the stomatal chambers which reflects the balance between stomatal conductance and photosynthetic rate photosynthetic rate is controlled primarily by photon flux sunshine and temperature suggesting that this dominates at three of the sites whereas stomatal conductance is controlled by air humidity and soil moisture status ant

is cellulose extraction necessary for developing stable carbon and oxygen isotopes chronologies from callitris glaucophylla abstract we examined the necessity of extracting cellulose for the development of stable carbon and oxygen isotope chronologies from callitris glaucophylla j thompson and l a s johnson cupressaceae we compared relationships among isotopes of whole wood cellulose and climate for the period 1979 1999 and using a moving interval technique with a 10 year window isotopes of whole wood and cellulose were significantly correlated and had similar relationships with climate when considered over the entire period in general variation in 13 c and 18 o was related to summer temperature relative humidity and rainfall however 13 c and 18 o of whole wood generally exhibited weaker and more variable correlations with climate through time than cellulose in addition isotopes of whole wood did not deviate from 1979 to 1999 mean values in the same way as isotopes of cellulose the instability of whole wood climate relationships may be due to the inclusion in whole wood of a climate signal from lignin that is more variable between tree rings than cellulose overall it appears that c glaucophylla at least whole wood does not record climate in the same way as cellulose and stable isotopes of cellulose provide a more temporally stable proxy of past climate we suggest that when developing isotope chronologies for other species the suitability of whole wood vs cellulose as a proxy for climate should be assessed with consideration of the temporal stability of their relationship with climate

base cation and silicon biogeochemistry under pine and scrub oak monocultures implications for weathering rates abstract vegetation type has a profound influence over biogeochemical processes including canopy leaching stemflow litterfall and nutrient uptake understanding the relationship between plants and soil processes such as mineral weathering is a difficult task considering the interactions among biotic and abiotic soil forming factors in this study soils planted with pure stands of scrub oak quercus dumosa nutt and coulter pine pinus coulteri b don were used to identify key biogeochemical processes in each soil plant system the experimental design a true biosequence allowed an opportunity to link biogeochemical processes to mineral weathering precipitation throughfall litter leachate and soil solutions were collected following rain events from november of 1996 to april of 1998 relatively high na and ca concentrations in pine throughfall suggest that atmospheric deposition is a more important process within the pine canopy than is canopy leaching in contrast to pine throughfall mean k concentrations were higher than ca in oak throughfall reflecting the importance of canopy leaching nutrient cycling was more rapid within the scrub oak soil plant system as evidenced by significantly reduced levels of cations in soil solution at the 7 5 cm depth compared to litter leachate mean si concentrations at the 65 cm depth were 334 mol l 1 under oak and 431 mol l 1 under pine silicon and base cation fluxes indicate higher weathering rates under pine solution chemistry shows that canopy and nutrient cycling processes are different between the two species and are impacting the cation loss rates

effects of vegetation type on the biogeochemistry of small catchments mont lozere france abstract input output budgets are presented for three granitic catchments with contrasting vegetation types spruce beech and grassland for the mont lozere region of france budget results are compared with information for analogous catchments with varying atmospheric pollution loading comparisons show relatively small losses of cations and marked sulphate retention in the soils particularly for the beech and grassland sites of the mont lozere catchments retention of sulphate may be underestimated particularly for the spruce site owing to occult and dry deposition inputs which have not been measured specific effects of the vegetation type upon the soil dynamics and the biological functioning of the ecosystem are described losses of the base cations are least significant for the beech forest and this is linked to low bicarbonate production coupled with high sulphate retention in the soil the spruce afforestation programme has led to a marked cation loss increase although the streams have yet to acidify deforestation leads to further cation losses in relation to increased nitrate leaching the biogeochemical functioning of the mont lozere ecosystems although slightly disturbed is not in steady state sulphate is still accumulating and the effects of afforestation and harvesting are marked

microclimate of arctic tree line 2 soil microclimate of tundra and forest forest and tundra soils display distinctive microclimates for a climatically normal year at churchill forest soils are substantially warmer in the active layer than those of the tundra but the tundra active layer is deeper forest soils are much wetter than those of the tundra this results from the deep winter snow pack which provides abundant meltwater to already thawed soils the soils remain wet throughout the year and the large latent heat release delays the freezing of forest soils until a snow pack is established as a result soils stay relatively warm throughout winter and thaw rapidly and deeply before snow pack melting in the spring the thaw period in the tree rooting zone is about 6 months compared to 4 months at the same depth in tundra the magnitude of soil heat storage is large comprising 18 and 16 of net radiation in tundra and forest respectively during the thaw season during freeze back it is the dominant heat exchange process between 80 and 90 of the total soil heat storage is involved in the latent heat exchange accompanying thawing and freezing soil heat flux plates strongly underestimate the ground heat exchange and are unreliable in permafrost terrain