mid cretaceous oceanic red beds in the umbria marche basin central italy constraints on paleoceanography and paleoclimate abstract detailed studies of the mid cretaceous sedimentary strata in the umbria marche basin in italy revealed that aside from several well known organic rich black shale horizons that record oaes several varicolored mainly reddish horizons indicate oxic conditions at the ocean bottom eight such horizons have been identified in aptian cenomanian sequences in the umbria marche basin the dysoxic oxic beds alternate regularly but not cyclically and seem to be the result of non random processes their occurrence is not a completely random process the duration of deposition of these oceanic red beds orbs varies from 0 13 my orb4 recorded in the ticinella primula zone to 4 54 my for orb1 which spans the globigerinelloides ferreolensis zone to the ticinella bejaouaensis zone in the piobbico core mid cretaceous orbs are not a local phenomenon because they occur in the tethyan deposits in the southern and austrian alps the carpathians the northern caucasus the central north atlantic in northeastern england and in the western himalayas they provide evidence for periodic changes in redox conditions at the ocean bottom such changes could have been caused by changes in bioproductivity basin geometry sedimentation rates paleocirculation and or production of bottom waters with higher content of dissolved oxygen in response to changes in paleoclimate we suggest that the periodic inflow of colder more oxygenated bottom waters was the probable cause of orbs development either as a result of changes in the ocean bottom topography or as a result of brief cool climate periods however reliable proxies for changes in deep ocean circulation are still lacking if orbs were the result of the paleoclimate and therefore indirectly caused by changes in co2 in atmosphere they document the increased sensitivity and instability of the mid cretaceous climate thus changes in ocean dynamics were on a scale of several hundred thousand years to several million years which has not been considered by most theories of co2 cycling mid cretaceous greenhouse paleoclimate and paleocean dynamics

assessing the greenhouse impact of natural gas 1 the global warming impact of substituting natural gas for coal and oil is currently in debate we address this question here by comparing the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction which could be achieved by instead substituting zero carbon energy sources we show that substitution of natural gas reduces global warming by 40 of that which could be attained by the substitution of zero carbon energy sources at methane leakage rates that are 1 of production which is similar to today s probable leakage rate of 1 5 of production the 40 benefit is realized as gas substitution occurs for short transitions the leakage rate must be more than 10 to 15 of production for gas substitution not to reduce warming and for longer transitions the leakage must be much greater but even if the leakage was so high that the substitution was not of immediate benefit the 40 of zero carbon benefit would be realized shortly after methane emissions ceased because methane is removed quickly from the atmosphere whereas co2 is not the benefits of substitution are unaffected by heat exchange to the ocean co2 emissions are the key to anthropogenic climate change and substituting gas reduces them by 40 of that possible by conversion to zero carbon energy sources gas substitution also reduces the rate at which zero carbon energy sources must eventually be introduced

global vegetation dynamics and latitudinal temperature gradients during the mid to late miocene 15 97 5 33 ma a 617 site palaeobotanical dataset for the mid to late miocene is presented this dataset is internally consistent and provides a comprehensive overview of vegetational change from 15 97 to 5 33 ma the palaeobotanical dataset has been translated into the biome4 classification scheme to enable direct comparison with climate model outputs the vegetation change throughout the langhian seravallian tortonian and messinian is discussed the data shows that the langhian which includes the end of the mid miocene climatic optimum represents a world significantly warmer than today the high northern latitudes were characterised by cool temperate forests the mid latitudes by warm temperate mixed forests the tropics by tropical evergreen broadleaf forests and antarctica by tundra shrub vegetation cool temperate mixed forest existed during the seravallian in the high northern latitudes a reduction in warm temperate mixed forests in the mid latitudes and a loss of tundra on antarctica was noted tortonian vegetation distribution indicates that further cooling had occurred since the seravallian the major changes in vegetation include the first evidence for cold taiga forest in the high northern latitudes and a further reduction of warm temperate mixed forests by the messinian this cooling trend had eliminated warm temperate mixed forests from the western usa and australia and had formed mid latitude deserts despite the cooling trend throughout the mid to late miocene the vegetation distribution of all four reconstructed stages reflect the vegetation of a world warmer than the pre industrial conditions the latitudinal distribution of bioclimatic zones suggests that the latitudinal temperature gradient for the langhian would have been significantly shallower than at present and has gradually but asymmetrically become more modern towards the end of the miocene first the southern hemisphere distribution of bioclimatic zones became more modern probably due to the climatic effects of a fully glaciated antarctica the northern hemisphere bioclimatic zone gradient continued to be shallower than modern throughout the miocene and slowly became more modern by the messinian

foliar physiognomic record of climatic conditions during dormancy climate leaf analysis multivariate program clamp and the cold month mean temperature abstract the extent to which the leaves of woody dicots encode in their physiognomy the climatic conditions that exist during dormancy was tested by sampling 20 sites along an approximately west east transect across european russia the crimean peninsula western siberia and central eastern siberia this transect encompassed the most extreme mean annual temperature range recorded in the modern world where vegetation exists climate leaf analysis multivariate program clamp revealed little change in calibration of the warm month mean temperature compared with the physg3ar data set derived from less extreme sites primarily in north america and japan but significant change with respect to the cold month mean temperature cmmt calibration although clamp underestimated the cmmt by up to 9 c in the coldest sites the addition of the transect sites improved clamp s performance at low temperatures this suggests that winter cold is encoded in foliar physiognomy even though the leaves are functional only duri

epiphyllous fungi and leaf physiognomy indicate an ever wet humid mesothermal subtropical climate in the late eocene of southern new zealand abstract a diverse group of epiphyllous fungi from at least 10 genera as well as numerous germlings were isolated from late eocene leaf litter preserved as carbonaceous material associated with the pikopiko fossil forest near tuatapere southland new zealand these fungi are associated with a variety of angiosperm leaves and together with clamp analyses of the fossil leaf assemblages at the site suggest that climatic conditions in the southern south island of new zealand at a palaeolatitude of 54 s during the late eocene ca 35 ma were mesothermal subtropical and had near permanent high vapour pressure the mesothermal conditions at mid latitudes in new zealand are concurrent with reduced latitudinal temperature gradients during the eocene high precipitation rates and humidity are suggestive of high moisture transport from lower latitudes

middle miocene climate and vegetation models and their validation with proxy data abstract the miocene is a relatively recent epoch of the earth s history with warmer climate than today particularly during the middle miocene climatic optimum mmco approximately 17 15 ma although the cause of the warming is probably not only attributable to co2 but also to changes in orography and configuration of ocean gateways this time interval represents an ideal case study to test the ability of climate models to simulate warm climates comparable to those that the earth may experience in the near future however even with higher than present day co2 concentrations the mmco warming inferred from terrestrial proxy data has been difficult to reproduce in climate models since fossil flora do not provide direct information on climate but on flora and vegetation climate model results are generally compared to climate reconstructions obtained from the fossil flora in this study we apply an alternative method by simulating palaeovegetation from the outputs of the climate model using a dynamic vegetation model model vegetation reconstruction can then be compared to the vegetation cover indicated by the fossil flora record at the various localities provided that a common classification of plant functional types pfts is used for the data and the model here we reconstruct the vegetation of the middle miocene with the global dynamic vegetation model caraib using the climatologies derived from five atmospheric general circulation models the reliability of the simulations is examined on a presence absence basis of pfts by comparison of vegetation reconstructions to palaeoflora data recorded in the northern hemisphere and the tropics this comparison provides an overall agreement around 60 between model and data when all sites and tree types are considered three model simulations out of five show to be better at predicting the absence than the presence the presence of warm temperate mixed forests in the middle latitudes dominated by broadleaved deciduous warm temperate and subtropical trees is generally well reproduced in caraib simulations however poor agreement is obtained for the presence of tropical pfts out of the tropics and for warm pfts at latitudes northward of 50 n where climate models remain too cold to produce assemblages of trees consistent with the data nevertheless the model data comparison performed here highlights several mismatches that could result not only from missing feedbacks in the climate simulations but also from the data the results of the likelihood analysis on presence absence of pfts illustrate the uncertainties in the pft classification of the neogene floral records the coexistence of some pfts in the palaeovegetation data is impossible to reproduce in the vegetation model simulations because of the climatic definition of the modern pfts this result indicates either a bias in the identification of modern analogues for fossil plant taxa or a possible evolution of environmental requirements of certain plants

paleoclimate estimates and fire ecology immediately prior to the end cretaceous mass extinction in the frenchman formation 66ma saskatchewan canada abstract the fossil rich deposits of the uppermost maastrichtian 66 ma frenchman formation of southern saskatchewan canada provide a detailed continuous record of terrestrial ecosystem dynamics during the last half million years leading up to the end cretaceous mass extinction paleoenvironmental interpretations for the frenchman formation are here refined by the first absolute paleoclimate estimates for the late cretaceous of saskatchewan and by the placement of these climate estimates within a north american context climate estimates were calculated using leaf margin analysis and the climate leaf analysis multivariate program clamp derived from two independent plant macrofossil assemblages collected from the frenchman formation climate parameter estimates indicate that the maastrichtian climate of southern saskatchewan was subtropical to warm temperate with mean annual temperatures between 12 c and 14 c and with marked seasonality these results are comparable with estimates derived from other late campanian and maastrichtian paleofloras in the western interior basin although small variations among coeval localities were noted or determined overall the plant fossil assemblages from the two study localities support the paleoenvironmental interpretation of the frenchman formation as a swampy to lowland forest system with canopy forming deciduous conifers and a diverse angiosperm dominated mid canopy and understory an unexpected marked disparity in plant diversity was found between the two paleofloras despite the plant assemblages returning similar paleoclimate parameter estimates abundant in situ inertinite fossil charcoal deposits were found in association with the less diverse paleofloral site which contained only angiosperm fossils inertinite was absent from the deposits containing the more diverse paleoflora which contained a different composition of angiosperm and gymnosperm fossils fire is known to be a prevalent feature of late cretaceous deposits worldwide and modern angiosperm plants typically are the first to recover following fire disturbances we suggest that the two frenchman formation paleofloras represent different stages of secondary ecological succession following a disturbance by fire the identification of fire ecology in the fossil record may have important implications for understanding biodiversity patterns on small spatial and temporal scales immediately prior to the cretaceous mass extinction

artificial neural networks reveal a high resolution climatic signal in leaf physiognomy the relationship linking leaf physiognomy and climate has long been used in paleoclimatic reconstructions but current models lose precision when worldwide data sets are considered because of the broader range of physiognomies that occur under the wider range of climate types represented our aim is to improve the predictive power of leaf physiognomy to yield climate signals and here we explore the use of an algorithm based on the general regression neural network grnn which we refer to as climate leaf analysis with neural networks clann we then test our algorithm on climate leaf analysis multivariate program clamp data sets and digital leaf physiognomy dlp data sets and compare our results with those obtained from other computation methods we explore the contribution of different physiognomic characters and test fossil sites from north america the clann algorithm introduced here gives high predictive precision for all tested climatic parameters in both data sets for the clamp data set neural network analysis improves the predictive capability as measured by r 2 to 0 86 for mat on a worldwide basis compared to 0 71 using the vector based approach used in the standard analysis such a high resolution is attained due to the nonlinearity of the method but at the cost of being susceptible to 39 noise 39 in the calibration data tests show that the predictions are repeatable and robust to information loss and applicable to fossil leaf data the clann neural network algorithm used here confirms and better resolves the global leaf form climate relationship opening new approaches to paleoclimatic reconstruction and understanding the evolution of complex leaf function

monsoon variability over peninsular india during late pleistocene signatures of vegetation shift recorded in terrestrial archive from the corridors of western ghats abstract the fossil flora recovered from the kangvai well ratnagiri district maharashtra 17 53 41 n 73 12 23 e has been used to reconstruct the monsoon variations and seasonal rainfall pattern during the late pleistocene 44 020 390 years bp by using the coexistence approach the reconstruction suggests that the southwest sw and northeast monsoons ne contributed 64 and 18 of the total rainfall respectively moreover the pre monsoon showers were responsible for about 15 of the annual rainfall as both sw and ne monsoons were very active along with the pre monsoonal rainfall the length of rainy season increased and extended up to 9 months in a year favouring the evergreen continuum and prevalence of wet evergreen forests until the late glacial maximum or slightly prior to it however due to the weakening of ne and pre monsoon rainfall later in the late pleistocene and early holocene the area experiences only four months of rainy season now on account of the present day sw monsoon these changes resulted in the extinction of wet evergreen taxa which are now endemic to the wetter parts of western ghats from the fossil locality our reconstruction agrees with the previous studies from the western ghats suggesting that the wet evergreen taxa require

mid cretaceous floras and climate of the russian high arctic novosibirsk islands northern yakutiya abstract two mid cretaceous floras collected in terrigenous and volcaniclastic deposits of the novosibirsk islands in the russian high arctic were studied these floras are the most poleward mid cretaceous floras known and existed at palaeolatitudes up to 82 85 n these represent our best insight into polar conditions at one of the warmest intervals in earth history an albian flora from the balyktakh formation of the kotel nyi island comprises 40 species of ferns bennettites cycadophytes ginkgoaleans czekanowskialeans conifers and gymnosperms incertae sedis this flora is most similar to the albian buor kemuss flora widespread in the arctic siberia and alaska and to a lesser extent to the aptian silyap flora of siberia a turonian flora from the derevyannye gory formation on the novaya sibir island includes approximately 50 taxa of ferns ginkgoaleans conifers and angiosperms this flora exhibits plants common for the early cretaceous as well as taxa typical for cenomanian senonian which implies that the age of the plant bearing deposits is likely to be turonian the cretaceous climate has often been described as warm with a higher degree of equability than today with the near polar regions in particular being much warmer than today our estimates using clamp and a new global gridded climate calibration demonstrate that for the turonian novaya sibir flora plant physiognomy reflects a humid climate with warm summers and mild frost free winters the mean annual temperature is estimated to have been 9 2 2 2 c the warm month mean temperature 17 2 2 8 c the cold month mean temperature 1 1 3 8 c and the mean growing season precipitation 537 392 mm these temperature parameters indicate that within 900 km of the turonian north pole the climate was similar to that of modern temperate or even warm temperate zones but must have differed considerably in having pronounced high latitude sunlight seasonality the ecology of the late cretaceous arctic plants reflects their adaptation to this climate synchronous shedding of foliage deciduousness was by far the most common strategy and retention of leaves year round evergreenness was also viable for a small number of taxa large deciduous leaves typical for the cretaceous arctic dicots probably reflect the combination of a warm and humid climate with high latitude light regime long days in summer and predominance of relatively weak and mostly diffuse sunlight the large range of leaf size in a given plant species of arctic angiosperms was most probably linked to the seasonal character of annual shoot development

the coexistence approach theoretical background and practical considerations of using plant fossils for climate quantification the coexistence approach was established by mosbrugger and utescher 1997 as a plant based method to reconstruct palaeoclimate by considering recent climatic distribution ranges of the nearest living relatives of each fossil taxon during its existence for over more than 15 years its basics have been tested and reviewed in comparison with other terrestrial and marine climate reconstruction techniques and climate modelling data however some controversies remain about its underlying data or its applicability in general in view of these controversies this paper discusses the power and limitations of the coexistence approach by summarising past results and new developments we give insights into the details and problems of each step of the application from the assignment of the fossil plant to the most suitable nearest living relative the crucial consideration of the usefulness of specific taxa towards their climatic values and the correct interpretation of the software based suggested palaeoclimatic intervals furthermore we reflect on the fundamental data integrated in the coexistence approach by explaining different concepts and usages of plant distribution information and the advantages and disadvantages of modern climatic maps additionally we elaborate on the importance of continually updating the information incorporated in the database due to new findings in e g palaeo botany meteorology and computer technology finally for a transparent and appropriate use we give certain guidelines for future applications and emphasize to users how to carefully consider and discuss their results we show the coexistence approach to be an adaptive method capable of yielding palaeoclimatic and palaeoenvironmental information through rime and space c 2014 elsevier b v all rights reserved

palaeoclimatic estimates for a latest miocene pliocene flora from the siwalik group of bhutan evidence for the development of the south asian monsoon in the eastern himalaya fossil leaf floras from the latest miocene pliocene siwalik group exposed in bhutan sub himalaya are subjected to a clamp climate leaf analysis multivariate program analysis using a high resolution gridded climate calibration the clamp analysis of 27 different morphotypes of fossil leaves indicates a mean annual temperature mat of 24 1 c 2 8 c a cold month mean temperature cmmt of 18 9 c 4 c and a warm month mean temperature wmmt of 27 8 c 3 3 c the analysis also suggests a weak monsoonal climate the monsoon index msi 46 7 present msi 52 with growing season precipitation gsp of 1819 916 mm present gsp 2490 mm here we also compare palaeoclimate estimates of the latest miocene pliocene siwalik group flora from bhutan c 6 to 3 8 ma with those of previously investigated siwalik group floras from the miocene pleistocene of arunachal india and miocene siwalik floras of darjeeling india which characterise the monsoon signature at the time of deposition since all the siwalik floras of the eastern himalaya darjeeling and arunachal pradesh spanning the mid miocene to pleistocene yield almost the same values we suggest that overall the eastern himalayan siwalik climate appears to have been remarkably uniform over the past 15 million years the mat result of the bhutan siwalik flora differs by just 0 6 c from arunachal and 1 2 c from darjeeling siwalik floras for all siwalik fossil assemblages wmmts cmmts and lgss length of the growing season are similar and consistent wmmts around 28 c cmmts around 18 c and lgss around 12 months similarly the mean annual relative humidity rh and specific humidity sh appear to have been uniformly around 80 and 14 g kg respectively throughout the neogene of the eastern himalayan siwaliks changes in the monsoon index suggest that in both bhutan and arunachal sub himalaya there has been little change in the intensity of the monsoon since mid miocene time while further west in the darjeeling area precipitation seasonality has increased since the mid miocene

contrasting palaeoenvironments of the mid late miocene dunedin volcano southern new zealand climate or topography abstract at the mid late miocene boundary a northward shift occurred in the subtropical front neighbouring the new zealand continental landmass the terrestrial palaeoenvironment of new zealand concurrently underwent a period of cooling the dunedin volcanic group in southern new zealand spans the mid late miocene boundary and the sedimentary deposits from kaikorai valley and double hill within this group contain diverse and well preserved floral assemblages we used terrestrial palaeoclimate proxies clamp climate leaf analysis multivariate program and ba bioclimatic analysis to determine the paleoenvironment at southern mid latitudes during the mid late miocene transition our results indicate that the mid late miocene climate of the dunedin volcano was warm temperate to subtropical mean annual temperature mat 17 19 c at double hill similar to modern coastal queensland and cool to warm temperate mat 12 14 c at kaikorai valley similar to modern northern new zealand winter temperatures at kaikorai valley were distinctly cooler 6 8 c differing aspect i e north vs south facing may have played a part in determining solar radiation particularly in an area of high relief such as the dunedin volcano because kaikorai valley was situated facing south and double hill facing north the two sites would have received differing radiative fluxes particularly in winter thereby possibly influencing the local environment biota and potentially also the palaeoclimate signal produced by floral proxies this study provides evidence for the temperature decline in terrestrial palaeoenvironments at mid latitudes caused by the northward movement of the subtropical front and strengthening of the antarctic circumpolar current during the mid late miocene

environmental analysis of the mid latitudinal european eocene sites of plant macrofossils and their possible analogues in east asia article i nfo previously known eocene floras of mid latitudinal europe are analysed using statistical methodologies in order to obtain more reliable palaeoclimatological signals to detect possible climatic fluctuations during this time interval only macrofossil assemblages have been taken into account and subjected to the statistical evaluation called the integrated plant record ipr vegetation analysis which is based mostly on percentages of various components additional palaeoclimatic approaches were employed namely the coexistence approach based on autecology of the nearest living relatives and the physiognomic methods of the leaf margin analysis and climate leaf analysis multivariate program clamp the same statistical approaches have been applied to analogous living vegetation of china and japan for comparative purposes additionally an update of objective statistical tools for the selection of the best suited modern vegetation clamp dataset from 144 site physg3br gridmet3br 173 physg3ar gridmet3ar and 189 physgasia1 gridmetasia1 extant biotopes is proposed including its copy paste excel application

why do foliar physiognomic climate estimates sometimes differ from those observed insights from taphonomic information loss and a clamp case study from the ganges delta abstract palaeoclimate estimates derived from plant based proxies are potentially subject to uncertainties arising from taphonomic filtering in any given fossil assemblage it is possible to identify the kinds of likely taphonomic influences but virtually impossible to quantify the uncertainties they introduce because filtering removes information because that information is missing it cannot be measured an alternative approach is to measure the maximum uncertainty possible due to specific information loss within recognised analytical protocols in respect of the multivariate foliar physiognomic technique known as clamp climate leaf analysis multivariate program we have attempted to do this by experimentally degrading both the character state scores and the number and composition of taxa as subsets of the full range of character states and taxonomic diversity in the source vegetation in this study a stand of protected vegetation on green island 23 08 58 n 88 26 59 19 e within the ganges delta was sampled following standard clamp protocols the island is subject to annual flooding during the monsoon season and is typical of the kinds of naturally disturbed vegetation likely to be represented in ancient delta floodplain assemblages a total of 56 woody dicot taxa were scored in the living vegetation from this complete sample leaf character states for lobing margin size apex base length to width ratio and shape were removed in turn from all 56 taxa to give 7 analyses simulating worst case taphonomic loss of physiognomic data ten subsets of 20 randomly selected taxa were also analysed to simulate taphonomic diversity loss of almost two thirds of the potentially available taxa in the source vegetation in all cases the completeness statistic remained above the clamp recommended minimum of 0 66 the results show that in all cases the uncertainties arising from taphonomic processes either through taphonomic diversity or character state filtering were not significantly different from the statistical clamp uncertainties associated with the most commonly used calibration dataset physg3brc and gave similar climatic estimates as the source vegetation in its entirety this suggests that stratigraphically well constrained museum collections lacking detailed sedimentary or taphonomic context can still be used with confidence for clamp analyses leaf margin analysis displayed a greater sensitivity to diversity loss the green island estimates suggested a cooler moister climate than that indicated by the observed regional climate as derived from a 0 5 0 5 gridded data set used in climate modelling evaluation the likely cause for this disparity is the prevalence of a sub canopy microclimate signal developed by the vegetation itself and this is strongly dependant on the temperature and humidity characteristics of the regional climate as well as the proximity to water bodies within the sample size limitations of this study this disparity is larger than that introduced by taphonomic processes but potentially can be corrected for

quantitative palaeoclimate estimates for early miocene southern new zealand evidence from foulden maar abstract a rich and diverse plant macrofossil assemblage from an earliest miocene diatomite deposit in southern new zealand provides a detailed record of mid latitude southern hemisphere terrestrial climate in an oceanic setting quantitative palaeoclimate estimates for temperature and precipitation variables were obtained using the climate leaf analysis multivariate program clamp and the bioclimatic analysis approach in addition the surface area of fossil podocarpus travisiae leaves preserved at the site was used as a proxy for mean annual temperature clamp and bioclimatic analysis both estimated mean annual temperatures at 18 5 19 5 c with a moderate seasonal temperature range between summer and winter of 10 c and leaf size in podocarpus suggested a mat of about 21 c precipitation rates were high at around 1700 2000 mm per year clamp analysis suggested a 600 mm difference between the dry and wet season whereas bioclimatic analysis indicated a 200 250 mm difference between summer and winter when compared to clamp analysis on modern vegetation on subtropical oceanic islands it would seem that clamp overestimates seasonal precipitation differences

refining clamp investigations towards improving the climate leaf analysis multivariate program clamp climate leaf analysis multivariate program has been used for the past 17 years to estimate palaeoclimatic conditions the reliability and applicability of this method based on leaf physiognomic characters of fossil woody dicots has been widely discussed over the same period the present study focuses on some technical aspects of clamp mainly on its robustness in the context of the theoretical unimodal requirements of canonical correspondence analysis and introduces correction coefficients for these aspects of the statistical approach as a new way of interpreting and improving on clamp estimates this tool was tested on datasets derived from 17 european fossil floras ranging in age from the late oligocene to the pliocene additionally an objective statistical method for the selection of the best suited modern vegetation dataset from 144 site physg3br or 173 physg3ar extant biotopes is proposed

asian eocene monsoons as revealed by leaf architectural signatures abstract the onset and development of the asian monsoon systems is a topic that has attracted considerable research effort but proxy data limitations coupled with a diversity of definitions and metrics characterizing monsoon phenomena have generated much debate failure of geological proxies to yield metrics capable of distinguishing between rainfall seasonality induced by migrations of the inter tropical convergence zone itcz from that attributable to topographically modified seasonal pressure reversals has frustrated attempts to understand mechanisms underpinning monsoon development and dynamics here we circumvent the use of such single climate parameter metrics in favor of detecting directly the distinctive attributes of different monsoon regimes encoded in leaf fossils leaf form adapts to the prevailing climate particularly under the extreme seasonal stresses imposed by monsoons so it is likely that fossil leaves carry a unique signature of past monsoon regimes leaf form trait spectra obtained from fossils from eocene basins in southern china were compared with those seen in modern leaves growing under known climate regimes the fossil leaf trait spectra including those derived from previously published fossil floras from northwestern india were most similar to those found in vegetation exposed to the modern indonesia australia monsoon i am which is largely a product of seasonal migrations of the itcz the presence of this distinctive leaf physiognomic signature suggests that although a monsoon climate existed in eocene time across southern asia the characteristics of the modern topographically enhanced south asia monsoon had yet to develop by the eocene leaves in south asia had become well adapted to an i am type regime across many taxa and points to the existence of a pervasive monsoon climate prior to the eocene no fossil trait spectra typical of exposure to the modern east asia monsoon were seen suggesting the effects of this system in southern china were a much later development

deriving temperature estimates from southern hemisphere leaves abstract the percentage of woody dicots with entire margined leaves in a flora is known to be positively correlated with mean annual temperature leaf margin analysis lma but this relationship is not globally uniform in particular the floras of australia and new zealand have been regarded as displaying a different physiognomic relationship to climate than floras seen in the northern hemisphere this difference is more marked in new zealand where the lma relationship appears entirely absent here we amass data for both northern and southern hemispheres using standard protocols and show that regional variations in the leaf margin mean annual temperature relationship are real but become less significant when other characters are included even new zealand falls into line and most of the mean annual temperature signal in new zealand floras is encoded in non margin features we introduce a new clamp climate leaf analysis multivariate program calibration dataset for the southern hemisphere comprising leaf physiognomic data from argentina bolivia south africa australia new zealand and other pacific islands that offers comparable precision for climate prediction to similar datasets derived from the northern hemisphere

the kanaka creek fossil flora huntingdon formation british columbia canada paleoenvironment and evidence for paleocene age using palynology and macroflora paleogene sediments of the huntingdon formation a correlative to the chuckanut formation of neighbouring washington state usa are exposed in the greater vancouver area british columbia canada

latest neogene monsoon of the chotanagpur plateau eastern india as revealed by fossil leaf architectural signatures abstract a fossil leaf assemblage from latest neogene pliocene sediments exposed in jharkhand of chotonagpur plateau eastern india is subjected to a clamp climate leaf analysis multivariate program analysis using a new high spatial resolution 1 km2 worldclim2 gridded climate data and physgasia2 calibration the clamp analysis of 80 different morphotypes of fossil leaves indicates a mean annual temperature mat of 21 9 c 2 3 c a cold month mean temperature cmmt of 16 7 c 3 5 c and a warm month mean temperature wmmt of 26 9 c 2 9 c precipitation estimates have high uncertainties but suggest a weak monsoon with a growing season 11 7 1 months precipitation gsp of 201 2 64 3 cm the new calibration also provides for the first time in india more detailed insights into the hydrological regime through the return of annual and seasonal vapour pressure deficit vpd and potential evapotranspiration pet estimates as well as new thermal overviews through measures of thermicity and growing degree days the new results confirm the overall warmth of the region although rainfall estimates have large uncertainties due to year round wet soils measures of vpd and pet show persistent high humidity but with higher evaporative stress in the summer during late neogene times than now

new developments in clamp calibration using global gridded meteorological data abstract climate leaf analysis multivariate program clamp is a versatile technique for obtaining quantitative estimates for multiple terrestrial palaeoclimate variables from woody dicot leaf assemblages to date it has been most widely applied to the late cretaceous and tertiary of the mid to high latitudes because of concerns over the relative dearth of calibration sites in modern low latitude warm climates and the loss of information associated with the lack of marginal teeth on leaves in paratropical to tropical vegetation this limits clamp s ability to quantify reliably climates at low latitudes in greenhouse worlds of the past one of the reasons for the lack of clamp calibration samples from warm environments is the paucity of climate stations close to potential calibration vegetation sites at low latitudes agriculture and urban development have destroyed most lowland sites and natural vegetation is now largely confined to mountainous areas where climate stations are few and climatic spatial variation is high due to topographic complexity to attempt to overcome this we have utilised a 0 5 0 5 grid of global interpolated climate data based on the data set of new et al 1999 supplemented by the era40 re analysis data for atmospheric temperature at upper levels for each location the 3 d climatology of temperature from the ecmwf re analysis project was used to calculate the mean lower tropospheric lapse rate for each month of the year the gridded data were then corrected to the altitude of the plant site using the monthly lapse rates corrections for humidity were also made from this the commonly returned clamp climate variables were calculated a bilinear interpolation scheme was then used to calculate the climate parameters at the exact lat long of the site when clamp analyses using the physg3br physiognomic data calibrated with the climate station based met3br were compared to analyses using the gridded data at the same locations gridmet3br the results were indistinguishable in that they fell within the range of statistical uncertainty determined for each analysis this opens the way to including natural vegetation anywhere in the world irrespective of the proximity of a meteorological station

paleoclimate and paleoecology of the latest eocene florissant flora of central colorado u s a abstract the uppermost eocene florissant formation of central colorado u s a contains a diverse flora and fauna preserved in lacustrine facies and represents a key episode in earth history immediately preceding the eocene oligocene boundary laminated shales contain impressions of non monocot angiosperm leaves that were used to estimate paleoecological and paleoclimatic parameters using leaf physiognomic methods including leaf mass per area ma digital leaf physiognomy dilp leaf margin analysis lma and leaf area analysis laa the majority 58 of the morphotypes analyzed for ma suggested a semi evergreen leaf lifespan whereas another 27 indicated a deciduous habit and 15 an evergreen habit there was no significant relationship between ma and insect damage based on a small subset of florissant s leaves higher ma values 73 of leaves one year lifespan coupled with a tendency toward long and narrow leaf shapes and small leaf areas indicate the existence of sclerophyllous vegetation using the global regression for mean annual temperature mat the dilp estimate of mat was anomalously cold 5 5 4 c however using a northern hemisphere regression the dilp mat estimate of 11 6 3 3 c was more plausible using dilp mean annual precipitation map was estimated at 740 608 334 mm yr 1 which supports dry conditions estimates for mat and map using the univariate lma and laa methods overlapped within uncertainty of the dilp results in addition those taxa classified as growing in wet areas riparian had significantly more teeth than non riparian taxa these paleoclimatic and paleoecological results suggest that outside the riparian forest the florissant flora sampled a seasonally dry temperate sclerophyllous shrubland to woodland perhaps similar to modern chaparral forests in the western interior of the u s a just before the transition into the cooler oligocene