multidisciplinary approach to reconstructing local pastoral activities an example from the pyrenean mountains pays basque in this study archaeology history and palaeoecology modern and fossil data sets of pollen and non pollen palynomorphs were used to reconstruct small scale pastoral activities in the pyrenees mountain during the last two millennia modern pollen assemblages from the major vegetation units both natural and anthropogenic are studied on one restricted watershed area a correlative model rda of 61 modern pollen spectra and 35 external variables distinguishes two groups of taxa providing information on the nature and spatial extent of human impact on the landscape the first pool indicates local pastoral activities and the second one implies regional input from outside the studied watershed and is not characteristic of a specific land use these pools are described as local pastoral pollen indicators lppi for this particular mountain region on crystalline bedrock and regional human activities pollen indicators rhapi the modern data set is used to aid interpretation of the local pollen sequence of sourzay that covers the last 2000 calendar years bp using rda reconstructions and best modern analogues as a means of comparing modern and fossil spectra the study also demonstrates agreement between the independent interpretations of two fossil proxies lppi and corophilous fungi

a review of glacial geomorphology and chronology in northern spain timing and regional variability during the last glacial cycle abstract in this paper we synthesize the research in glacial geomorphology and geochronology in northern spain with special attention to the evidence of local glacier maximum extent earlier than the global lgm of mis 2 18 21 ka bp more accurate models of glacier evolution have been defined based on limnogeological geochronological and geomorphological data in the pyrenees osl optically stimulated luminescence surface exposure and radiocarbon dating techniques have identified end moraines and fluvial terraces corresponding to mis 6 about 170 ka and even to mis 8 about 260 ka and also established the timing of the last local glacial maxima as prior to global lgm mis 4 ca 50 70 ka during the global lgm a smaller re advance occurred but glaciers reached different extents in the central and the eastern pyrenees in nw iberia radiocarbon and osl techniques point to local glacial maximum prior to ca 26 ka 38 ka and probably synchronous with 45 ka although some bias might have been introduced by the dating procedures this review demonstrates that in both regions the local maximum extent occurred prior to the global lgm the asynchronies between the glacial maxima chronologies in the different mountain ranges of northern spain suggest that local climate factors exert a strong control on mountain glacier dynamics

cosmic ray labeling of erosion surfaces in situ nuclide production rates and erosion models a number of in situ cosmogenic radionuclides and stable nuclides have been measured in natural exposed rock surfaces with a view to study their in situ production and rock erosion rates 1 the in situ radionuclides can be used for a high resolution tomography of the erosional history of an exposed surface two stable nuclides 3he 21ne and five radionuclides 10be 26al 36cl 14c 39ar having half lives in the range of 300 1 5 106 yr half life are measurable in many rock types a prerequisite for the application of the in situ nuclides for the study of erosional histories of surfaces is a knowledge of their production rates under different irradiation conditions altitude latitude irradiation geometry and shielding relative nuclide production rates can be determined fairly accurately using the extensive available data on cosmic ray neutrons 2 absolute nuclide production rates cannot generally be predicted with any accuracy because of lack of data on excitation functions of nuclides unless some normalization is possible as was done in the case of several cosmic ray produced isotopes in the atmosphere 3 based on a recent natural calibration experiment in which erosion free surfaces exposed to cosmic radiation for 11 000 yrs were sampled the absolute production rates of 10be and 26al in quartz have been accurately estimated for mountain altitudes in sierra nevada 4 the absolute production rates of 10be and 26al in quartz can therefore be estimated fairly accurately for any given latitude and altitude some measurements of 14c in rocks of low erosion rate 5 similarly allow an estimate of its production rate attempts made to measure the in situ production rates of 3he in rocks have not yet led to a convergent production rate in view of the importance of knowing the production rates of isotopes of he ne and ar i present here theoretical estimates of their production rates based on available cross section data i discuss the information that can be extracted from the study of the in situ nuclides in rocks useful parameters characterizing the exposure history of a rock surface are 1 the effective surface exposure age and 2 the time averaged erosion rate the implications of these parameters for single and multiple nuclide studies are discussed in terms of the erosion models considered

sporormiella fungal spores a palynological means of detecting herbivore density during the historic period spores of the dung fungus sporormiella are abundant in lake and cave sediment where livestock are plentiful in the western united states sporormiella spores occasionally exceed 50 of the upland pollen sum in samples from corral ponds and bed grounds and routinely reach 4 in lake and marsh samples in pastoral areas sporormiella spores are comparatively rare in mid holocene sedimentary records but they reach values of 2 4 in pleistocene samples from lake sediments sporormiella spores are directly linked to extinct megaherbivores by their presence in mammoth dung from bechan cave utah in several sites in the western united states a precipitous decline of sporormiella percentages after ca 10 800 radiocarbon yr b p 12 900 years ago marks a decline of herbivore density probably associated with the north american megaherbivore extinction

2000 year environmental history of a karstic lake in the mediterranean pre pyrenees the estanya lakes spain abstract the sediment record of the estanya lakes pre pyrenees spain indicates that this region was intensely affected by land use during the middle and modern ages which contrasts with the present day poor socioeconomic development of the region the correlation between sediment and biotic data and well known historical events suggests a reliable history of environmental changes in this area during the last 2000 years changes in lake level were mainly controlled by climatic factors whereas properties such as lithology organic carbon ostracods and pollen content are mainly associated with lake management and land use major sedimentological changes resulted from the use of the lake for hemp retting at the start of the xivth century subsequent depopulation of the area in the xxth century led to the progressive recovery of the lacustrine ecosystem

tracing the history of highland human management in the eastern pre pyrenees an interdisciplinary palaeoenvironmental study at the pradell fen spain although high mountain areas have traditionally been viewed as predominantly grazing areas with low population and a high degree of land use stasis recent research suggest that land use complexity and change over time has been underestimated this interdisciplinary palaeoenvironmental analysis has been carried out on the pradell calcareous fen located in the eastern pre pyrenees spain at 1975 m a s l and it comprises different environmental indicators pollen stomata non pollen palynomorphs macrocharcoal particles lithostratigraphy sedimentology and geochemistry the results of this high temporal resolution study are integrated with archaeological data and together provide strong evidence for the complexity of the high mountain land use system over the last 1500 years archaeological fieldwork has shown the rise of highland mining activities during the roman period later frequent fires resulted from the farming and settlement that followed the christian conquest geochemical analysis of sediment cores records late mediaeval metal production while the expansion of feudal cropping and the advent of several mediaeval crises are clearly recorded in both the pollen and the historical data finally the rise of a mixed economy system based on transhumance farming metallurgy and woodland exploitation was established during modern and contemporary times the high correlation between the palaeoenvironmental archaeological and historical data at the pradell fen stresses the value of calcareous fens for palaeoenvironmental reconstructions of historical landscapes results obtained also depict high mountain landscapes as the result of the long term interaction of many human practices including mining and smelting grazing cropping and tree exploitation for the production of wood charcoal and resin

degradation of unconsolidated quaternary landforms in the western north america abstract one of the major goals of geomorphology is to understand the rate of landscape evolution and the constraints that erosion sets on the longevity of land surfaces the latter has also turned out to be vital in modern applications of cosmogenic exposure dating and interpretation of lichenometric data from unconsolidated landforms because the effects of landform degradation have not been well documented disagreements exist among researchers regarding the importance of degradation processes in the dating techniques applied to exposures here we show that all existing qualitative data and quantitative markers of landform degradation collectively suggest considerable lowering of the surface of unconsolidated landforms over the typical life span of quaternary moraines or fault scarps degradation is ubiquitous and considerable even on short time scales of hundreds of years on steeply sloping landforms these conservative analyses are based entirely on field observations of decreasing slope angles of landforms over the typical range of ages in western north america and widely accepted modeling of landscape degradation we found that the maximum depth of erosion on fault scarps and moraines is on average 34 of the initial height of the scarp and 25 of the final height of the moraine although our observations are limited to fault scarps and moraines the results apply to any sloping unconsolidated landform in the western north america these results invalidate the prevailing assumption of no or little surface lowering on sloping unconsolidated landforms over the quaternary period and affirm that accurate interpretations of lichen ages and cosmogenically dated boulder ages require keen understanding of the ever present erosion in our view the most important results are twofold 1 to show with a large data set that degradation affects universally all sloping unconsolidated landforms and 2 to unambiguously show that even conservative estimates of the total lowering of the surface operate at time and depth scales that significantly interfere with cosmogenic exposure and lichen dating

a re evaluation of the vegetation history of the eastern pyrenees france from the end of the last glacial to the present abstract fourteen pollen records obtained from 10 sites in the eastern pyrenees are presented along with the results of 40 new radiocarbon dates of samples obtained from these sites the data 784 pollen spectra provide a more comprehensive evaluation of the vegetation history of the region than has hitherto been possible the salient elements of the regional plant succession are described in the light of a study of regional pollen rain vegetation relationships vegetational developments during the last glacial interglacial transition and the holocene are compared with those of other regions in france and the western mediterranean this approach therefore provides a new synthesis of published and unpublished information over a large area a consistent and coherent pattern emerges and the new evidence indicates a number of previously held views on the vegetation history of the pyrenees to be erroneous

holocene high altitude vegetation dynamics in the pyrenees a pedoanthracology contribution to an interdisciplinary approach abstract using an interdisciplinary methodology based on pedoanthracology palynology and sedimentary charcoals landscape transformation in the pyrenees mountains during the holocene is analyzed with special attention to altitudinal variation in the treeline the data sources were eight soil profiles on a transect at 2000 2600 m a s l and a sedimentary record extracted from a very nearby peat bog at 2247 m a s l the combination of three different proxies permits a more viable and qualitatively complementary data set making it possible to better interpret the vegetation dynamic in this space through the holocene analysis of the data showed that the pyrenees landscape has undergone important changes during this period the changing treeline is a good example there is evidence of the decisive role of fire in the configuration of this landscape finally this study shows that herding and agricultural uses over thousands of years in the study area have had a determining influence on the current configuration of the territory equal to or more important than climatic factors

cosmic ray produced 10be and 26al in antarctic rocks exposure and erosion history we have measured cosmic ray produced t1 2 1 5 million years 10be and t1 2 0 705 million years 26al in purified quartz fractions of selected rock samples from antarctic mountains from these data we calculate 1 mean erosion rates for the limiting case of steady state surface exposure to cosmic rays and 2 minimum exposure ages for the limiting case of no erosion calculated mean erosion rates are very low on the order of a few times 10 5 cm yr we believe the sampling to be sufficient to generalize this result to exposed bedrock in antarctica in favorable cases it is possible to distinguish between the limiting cases steady state erosion seems a better description in such cases most samples including some taken a few meters above the present ice level seem to have been exposed for millions of years without major episodes of burial or abrasion by ice

u series isochron dating a generalized method employing total sample dissolution the age of a sedimentary deposit can be determined by measuring 238u 234u 232th and 230th in two or more samples of the deposit with the requirement that these samples have different u th ratios but an identical 230th232th ratio when deposited this paper presents the theoretical and experimental aspects of the dating method the latter involves techniques for securing samples of varied u th ratios from the same deposit plotting isochrons of the radiochemical data obtained on totally dissolved samples for age analysis and estimating the errors involved although applications to impure carbonates and lacustrine evaporite sediments are given as examples in this paper the method potentially can be generalized for dating a variety of authigenic deposits such as rock varnish peat opal sulfate minerals and marine phosphorites

climate variability in the spanish pyrenees during the last 30 000 yr revealed by the el portalet sequence abstract palynological sedimentological and stable isotopic analyses of carbonates and organic matter performed on the el portalet sequence 1802 m a s l 42 48 00 n 0 23 52 w reflect the paleoclimatic evolution and vegetation history in the central western spanish pyrenees over the last 30 000 yr and provide a high resolution record for the late glacial period our results confirm previous observations that deglaciation occurred earlier in the pyrenees than in northern european and alpine sites and point to a glacial readvance from 22 500 to 18 000 cal yr bp coinciding with the global last glacial maximum the patterns shown by the new high resolution pollen data from this continental sequence chronologically constrained by 13 ams 14c dates seem to correlate with the rapid climate changes recorded in greenland ice cores during the last glacial interglacial transition abrupt events observed in northern latitudes heinrich events 3 to 1 oldest and older dryas stades intra allerod cold period and 8200 cal yr bp event were also identified for the first time in a lacustrine sequence from the central western pyrenees as cold and arid periods the coherent response of the vegetation and the lake system to abrupt climate changes implies an efficient translation of climate variability from the north atlantic to mid latitudes

accuracy of cosmogenic ages for moraines analyses of all published cosmogenic exposure ages for moraine boulders show an average age range of 38 between the oldest and youngest boulders from each moraine this range conflicts with the common assumption that ages of surface boulders are the same as the age of the landform the wide spread in boulder ages is caused by erosion of the moraine surface and consequent exhumation of fresh boulders a diffusion model of surface degradation explains the age range and shows that a randomly sampled small set of boulders n 3 7 will always yield a lower age limit for the moraine the model indicates that for identical dating accuracy six to seven boulders are needed from old and tall moraines 40 000 100 000 yr 50 100 m initial height but only one to four boulders from small moraines 20 000 100 000 yr 10 20 m by following these guidelines the oldest obtained boulder age will be 90 of the moraine age 95 probability this result is only weakly sensitive to a broad range of soil erosion rates our analysis of published boulder ages indicates that 3 of all moraine boulders have prior exposure and 85 of these boulders predate the dated moraine

reconstructing holocene water tables in new zealand using testate amoebae differential preservation of tests and implications for the use of transfer functions testate amoebae analysis is used to provide the e rst quantitative reconstruction of holocene surface wetness changes from a southern hemisphere ombrogenous bog water table depth and surface moisture are the dominant environmental factors ine uencing testate amoebae species composition in a modern training set of 62 surface samples from 19 bogs in new zealand a transfer function based on partial least squares pls performed well in cross validation of modern samples but produced unrealistic predictions of water table depth and moisture for fossil samples this resulted from poor overlap of species composition between modern and fossil samples peat humie cation data is used to examine decay related species diversity trends and ordination is used to explore the differences between modern and fossil assemblages poor overlap can be explained by differential preservation in the fossil assemblages of those taxa with more robust tests this enhances their abundance and reduces the overall diversity of the fossil assemblages human activities over the last 150 years have also ine uenced the surface environments and hydrology of the sampled bogs in this situation weighted average wa and tolerance downweighted weighted average wa tol models were more robust than pls and were applied along with semi quantitative scoring to reconstruct more realistic holocene surface wetness changes selection of the best model for reconstruction of surface wetness changes should be based on the characteristics of the fossil data rather than the predictive power of the model in cross validation of the modern data alone

climatic and topographic controls on the style and timing of late quaternary glaciation throughout tibet and the himalaya defined by 10be cosmogenic radionuclide surface exposure dating abstract temporal and spatial changes in glacier cover throughout the late quaternary in tibet and the bordering mountains are poorly defined because of the inaccessibility and vastness of the region and the lack of numerical dating to help reconstruct the timing and extent of glaciation throughout tibet and the bordering mountains we use geomorphic mapping and 10 be cosmogenic radionuclide crn surface dating in study areas in southeastern gonga shan southern karola pass and central western nyainqentanggulha shan and tanggula shan tibet and we compare these with recently determined numerical chronologies in other parts of the plateau and its borderlands each of the study regions receives its precipitation mainly during the south asian summer monsoon when it falls as snow at high altitudes gonga shan receives the most precipitation 2000 mm a 1 while near the margins of monsoon influence the karola pass receives moderate amounts of precipitation 500 600 mm a 1 and in the interior of the plateau little precipitation falls on the western nyainqentanggulha shan 300 mm a 1 and the tanggula shan 400 700 mm a 1 the higher precipitation values for the tanggula shan are due to strong orographic effects in each region at least three sets of moraines and associated landforms are preserved providing evidence for multiple glaciations the 10 be crn surface exposure dating shows that the formation of moraines in gonga shan occurred during the early mid holocene neoglacial and little ice age on the karola pass during the lateglacial early holocene and neoglacial in the nyainqentanggulha shan date during the early part of the last glacial cycle global last glacial maximum and lateglacial and on the tanggula shan during the penultimate glacial cycle and the early part of the last glacial cycle the oldest moraine succession in each of these regions varies from the early holocene gonga shan lateglacial karola pass early last glacial western nyainqentanggulha shan and penultimate glacial cycle tanggula shan we believe that the regional patterns and timing of glaciation reflect temporal and spatial variability in the south asian monsoon and in particular in regional precipitation gradients in zones of greater aridity the extent of glaciation has become increasingly restricted throughout the late quaternary leading to the preservation of old 100 ka glacial landforms in contrast in regions that are very strongly influenced by the monsoon 1600 mm a 1 the preservation potential of pre lateglacial moraine successions is generally extremely poor this is possibly because lateglacial and holocene glacial advances may have been more extensive than early glaciations and hence may have destroyed any landform or sedimentary evidence of earlier glaciations furthermore the intense denudation mainly by fluvial and mass movement processes which characterize these wetter environments results in rapid erosion and re sedimentation of glacial and associated landforms which also contributes to their poor preservation potential

lower mediterranean plain accelerated evolution during the little ice age geoarchaeological insight in the tech basin roussillon gulf of lion western mediterranean abstract this paper discusses the evolution of the tech river lower plain western mediterranean from the late middle ages using geomorphological archaeological and historical data geoarchaeological data was obtained from coring and trenching near a buried village and chapel radiocarbon and archaeological dating are used to reconstitute sedimentation rates and major flood event chronology additional data about channel avulsion are provided by historical data increases in sedimentation rate flooding plain enlargement and repeated avulsion are identified between the last 13th to 15th century ad this attests to a shift from low water level regime lwr to flood dominated regime fdr climatic or anthropogenic causes of this change are discussed on the basis of regional synthesis on the western mediterranean scale 1250 1350 ad seems to be a wetter phase associated with the progressive onset of the early little ice age phase from 1330 to 1450 ad

glacial to interglacial vegetation changes in the northern and southern pyrenees deglaciation vegetation cover and chronology abstract new palynological investigations have been carried out in the southern northern and mediterranean part of the pyrenean chain pollen percentage and concentration diagrams are compared for a period including the end of the glacial period the late glacial and postglacial periods from the new results and from comparisons with previous published data the steppe and semi desert vegetation of the end of the last glacial period are described as well as the plant communities of the period 15 13 ka a dry climate was responsible for the early glacial retreat before 30 ka deglaciation was continuous up to about 15 14 ka without any readvance around 20 18 ka different aspects of the late glacial vegetation are studied and the first stages of the postglacial are described the younger dryas event is found everywhere but particularly clearly in the mediterranean area the most important 14 c dates are discussed and a plateau of 14 c ages is clearly visible around 10 000 bp

himalayan glacial sedimentary environments a framework for reconstructing and dating the former extent of glaciers in high mountains abstract reconstructing paleoenvironmental change from glacial geologic evidence in the himalayas has been difficult because of the lack of organic material for radiocarbon dating and the problems of correctly identifying the origin of highly dissected landforms studies of the contemporary glacial depositional environments and ancient landforms and sediments in the hunza valley karakoram mountains the lahul and garhwal himalaya and the khumbu himalaya illustrate the variability in processes landforms and sediment types these studies can be used to interpret ancient landforms and sediments for paleoenvironmental reconstructions and aid in forming strategies for sampling sediments and rocks for the developing techniques of cosmogenic radionuclide crn surface exposure and optically stimulated luminescence osl dating many himalayan glaciers have thick covers of supraglacial debris derived from valley sides and such debris mantled glaciers exhibit important differences from clean glaciers both in terms of debris transport processes and the depositional landforms that they produce analysis of sediment landform associations can be used to reconstruct processes of sediment transport and deposition and the relationship between moraines and other landforms and climatic forcing cycles such analysis is of fundamental importance in guiding sampling and interpretation in crn and osl dating work

terrestrial cosmogenic surface exposure dating of glacial and associated landforms in the ruby mountains east humboldt range of central nevada and along the northeastern flank of the sierra nevada abstract deposits near lamoille in the ruby mountains east humboldt range of central nevada and at woodfords on the eastern edge of the sierra nevada each record two distinct glacial advances we compare independent assessments of terrestrial cosmogenic nuclide tcn surface exposure ages for glacial deposits that we have determined to those obtained by others at the two sites at each site tcn ages of boulders on moraines of the younger advance are between 15 and 30 ka and may be associated with marine oxygen isotope stage mis 2 at woodfords tcn ages of boulders on the moraine of the older advance are younger than 60 ka and possibly formed during mis 4 whereas boulders on the correlative outwash surface show ages approaching 140 ka mis 6 the tcn ages of boulders on older glacial moraine at woodfords thus appear to severely underestimate the true age of the glacial advance responsible for the deposit the same is possibly true at lamoille where clasts sampled from the moraine of the oldest advance have ages ranging between 20 and 40 ka with a single outlier age of 80 ka the underestimations are attributed to the degradation and denudation of older moraine crests noting that boulder ages on the older advances at each site overlap significantly with mis 2 we speculate that erosion of the older moraines has been episodic with a pulse of denudation accompanying the inception of mis 2 glaciation

7000 years of vegetation history and land use changes in the morvan mountains france a regional synthesis this paper aims to reconstruct the vegetation history of a middle mountain the morvan burgundy france since the neolithic i e 7000 years the results of palynological and non pollen palynomorphs npps analysis performed on 10 peat cores document the main phases of human agro pastoral practices and natural resources management which drove the formation of the cultural landscape of the morvan massif over time to document the history of human activities at a regional scale particular attention was given to the determination the characterization and the graphical depiction of phrases of human impact both the quantification of the impact of human pressure and the chronological uncertainty of the different phases identified by pollen and npp analysis were taken into account this study reveals a clear human presence during periods that were formerly poorly documented such as the onset of the neolithic period the bronze age the early iron age and the early middle ages it also sheds new light over periods for which there is better archaeological and historical knowledge such as the widespread occupation of the massif in the late iron age the cultivation of chestnut from the 11th to the 16th century and the impact of modern firewood exploitation on the forest

denudation rates for the southern drakensberg escarpment se africa derived from in situ produced cosmogenic 36c1 initial results cosmogenic 36 c1 concentrations in basalt samples from the drakensberg escarpment on the se african passive margin give quantitative estimates of denudation and scarp retreat rates over the 10 4 10 6 year timespan addressed by these data the calculated escarpment retreat rate has been 50 95 m ma 1 and the average summit denudation rate 6 m ma 1 the scarp retreat rate is an order of magnitude less than previously suggested the rate of summit lowering is sufficient to prevent the long term intact survival of erosion cycle surfaces formed in the mesozoic that were previously inferred for this region

rates of basin wide rockwall retreat in the k2 region of the central karakoram defined by terrestrial cosmogenic nuclide 10be abstract basin wide rockwall retreat rates are estimated using cosmogenic 10 be concentrations in supraglacial debris from the baltoro glacier basin in k2 region of the central karakoram pakistan total cosmogenic 10 be concentrations of the supraglacial debris were measured using accelerator mass spectrometry to determine 10 be concentrations inherited from the rockwalls within the glaciated basin given that rockfall induced by periglacial weathering and snow and ice avalanches is the most important source of supraglacial debris production in the high mountain glaciated basin the erosion rate of the bare bedrock can be considered to be the rate of rockwall retreat the rate of the rockwall erosion converted from the calculated inheritance of 10 be concentrations using the maximum velocity of the active glacier places an upper limit ranging from 0 65 mm year to 2 48 mm year this rate of rockwall retreat is in the same order of magnitude reported in other high himalayan mountains the rate however is an order of magnitude higher than erosion rates inferred from sediment budget studies and half that of the fluvial incision rate and exhumation rate for the same region the difference between rates of basin wide rockwall retreat and fluvial incision rates over the late quaternary suggests that in this glaciated basin fluvial incision is likely enhanced by localized differential tectonism and or isostatic uplift

landscape human shaping and spatial mobility of agropastoral practices in the chaine des puys during historical times massif central france abstract the chaine des puys is a great collection of extinct volcanoes that cover the hercynian basement and belongs to the auvergne volcanoes natural regional park both the sedimentary record and the historical archives of this area are numerous however the cores studied hitherto do not offer a good knowledge of the historical dynamics because most of the wetlands have dried out during historical times causing gaps in the sedimentary record and pollen oxidization moreover all the studied cores are located on the crystalline basement or on an old volcanic one predating the chaine des puys thus they do not directly provide information about the volcanoes this article presents the only core obtained from a site a small maar located on a volcano the sequence is short but does not have the same sedimentary gaps as the others owing to physical grain size chemical c n p k ca mg n no 3 n nh 4 palaeoecological pollen and non pollen palynomorphs and historical analyses this study gives a more precise recording of the landscape changes during the last 500 years in the volcanic area and contributes to the knowledge of the chaine des puys landscape it illustrates the mobility of the historical landscape in particular the progression and regression of the forest and the erosive crises related to more intensive grazing activity the observations are linked with the social and economical changes especially with the consequences of the french revolution and the rural depopulation this landscape history gives data about the direction of changes to the landscape preservationists they demonstrate that even if the chaine des puys landscape looks natural it has been shaped by a very specific socio economical system inherited from the middle ages these aspects could be integrated in a management plan

spatial temporal distribution and geographic context of neolithic cultural sites in the hanjiang river basin southern shaanxi china abstract understanding how to live successfully within our environment is among the most pressing challenges facing contemporary society this paper probes the problem based on comparative analysis and discusses the relationship between the spatial temporal distribution of the neolithic cultural sites and the geographic context in the hanjiang river basin in the south of shaanxi province china archaeological studies have identified 175 neolithic cultural sites in the study area with a sequence of laoguantai 14 c age 8 7 ka bp yangshao 14 c age 7 5 ka bp and the late period of the neolithic age 14 c age 5 4 ka bp the total number of archaeological sites the distribution area and the density all showed an early ascending and later descending trend but the proportion of the number of archaeological sites in the study area to the corresponding value of the entire shaanxi province declined sharply spatially these sites were concentrated on the terraces of the hanjiang river and its main tributaries with an altitude of 400 800 m multiple data were integrated to clarify the critical effects of tectonic and geomorphologic conditions on the distribution of the neolithic sites further comparisons revealed the correlation of holocene climate change and environmental evolution with the neolithic cultural succession in the study area that ameliorated conditions to generally promote the development of the primitive culture while degeneration coincided with the culture s transition or interruption the discussion on the origin of the primitive culture and the temporal spatial distribution corresponding to the regional culture differentiation sheds light on the complex and dynamic human nature interaction system during the neolithic age thus emphasising the wider field based investigation and high resolution reconstruction works of the palaeoclimate and palaeoenvironment in the future

chrysophyte cysts from lake sediments reveal the submillennial winter spring climate variability in the northwestern mediterranean region throughout the holocene in the last decade much effort was dedicated to the reconstruction of past climate at high temporal resolution here we show the suitability of chrysophyte cysts from lake sediments for revealing continental climate variability when used in sensitive sites such as those in high mountains we demonstrate that altitude is a main factor influencing the present distribution of chrysophytes and develop a transfer function to evaluate the local altitude anomaly on a lake site throughout time based on our knowledge of chrysophyte ecology the altitude anomalies are interpreted as winter spring climate signatures the method was applied to a holocene record from a lake in the pyrenees showing submillennial climatic variability in this northwestern mediterranean zone a warming trend was present from the early holocene to 4 kyear bp comparison with pollen based reconstructions of summer temperatures denoted a contrasting decrease in continentality between the two parts of the holocene oscillations of 1 cycle per ca 2 000 years appeared throughout the record the warmest holocene winters were recorded during the medieval warm period at ca ad 900 and 450 and the roman warm period 2 7 2 4 kyear bp winters in the period ad 1 050 1 175 were inferred to be as cold as in the little ice age the period between 3 and 7 kyear bp showed lower intensity in the fluctuations than in early and late holocene the cold event 8 200 years ago appeared embedded in a warm fluctuation another cold fluctuation was recorded around 9 kyear bp which is in agreement with irish and greenland records

tracing the land use history and vegetation dynamics in the mont lozere massif central france during the last 2000 years the interdisciplinary study case of countrasts peat bog the countrasts bog 1400 m a s l located in the western part of the mont lozere medium mountain has been the object of an interdisciplinary study combining multiproxy analyses which includes pollen non pollen palynomorphs npp macrocharcoal particles sedimentology and geochemistry with archaeological and archaeobotanical data the high temporal resolution of the palaeoenvironmental study with an average resolution of 40 years between samples allows us to trace the landscape dynamics for the last 2000 years at a micro regional scale during the roman imperial period ca 1st 3rd centuries ad local agropastoral activities were moderate whereas metallurgical activities developed in the region as attested by geochemical records later during late antiquity and early medieval periods ca 3rd 10th centuries ad agropastoral activities increased and human impact produced major changes in local mire dynamics with the replacement of birch wooded bogs by sedge communities during the high middle ages ca 10th 13th centuries ad a complex system of land uses was established based on different activities including ore smelting forestry and agropastoralism attested by pollen npp and geochemistry data as well as by archaeological archaeobotanical and historical evidence since the late middle ages ca 14th century ad local metallurgical activities and forestry management decline have coincided with the expansion of grazing in uplands this new land use favored the expansion of upland grasslands and heathlands and triggered the establishment of an open landscape during the early modern period ca 15th 18th centuries ad at the end of the 19th century and the 20th century agropastoral activities declined while reforestation was carried out

rupture properties of the giant sumatra earthquake imaged by empirical green s function analysis empirical green s function egf analysis has remained little used to image the rupture properties of the giant 26 december 2004 sumatra earthquake the 2 november 2002 foreshock m w 7 2 close to the mainshock epicenter gives us the opportunity to use its waveforms to empirically simulate the rayleigh wave propagation of the sumatra earthquake we first show that the exceptional size of the sumatra earthquake does not prevent use of the egf technique four aftershocks m w 5 9 6 1 distributed along the sumatra andaman trench are shown to have consistent rayleigh waves for periods between 100 and 200 sec at a lower frequency we present two large earthquakes of the mexican subduction zone m w 7 2 7 3 close to the selected egf magnitude for which long period green s functions 100 2000 sec remain very similar even if event epicenters are separated by about 650 km this justifies the possibility of using the 2002 foreshock as an egf for the whole rupture process of the sumatra earthquake and shows more generally the very broad range of application of egf technique then a specific analysis reveals that seismic moment magnitude is close to 9 1 seismic moment equal to 5 6 10 22 n m moment release analysis along the sumatra andaman trench shows two main slip episodes one next to the northern extremity of sumatra 20 m slip and the other one along the nicobar islands 10 m slip with a global extent of 1150 1200 km rupture velocity varies between values around 2 5 km sec in the first half of the rupture and values closer to 2 km sec in the second half total duration imaged by rayleigh waves is 580 sec 20 sec and no activity of the fault is found in the time scale between 600 and 2000 sec in the hypothesis of even longer timescale slip this phenomenon would be of the order of 10 20 of the global moment and likely restricted to the andaman islands

natural controls of fluvial denudation rates in major world drainage basins we present a new compilation of estimates of modern rates of mechanical and chemical denudation for externally drained basins exceeding 5 105 km2 in area these estimates are based on sediment and solute load data selected in order to represent natural rates as far as possible chemical denudation rates have been calculated by deducting the nondenudational component of solute load mechanical denudation rates range from 1 mm kyr 1 for the st lawrence and dnepr basins to 670 mm kyr 1 for the brahmaputra basin chemical denudation rates vary from 1 mm kyr 1 kolyma niger nile and rio grande basins to 27 mm kyr 1 chiang jiang basin the kolyma basin has the lowest 4 mm kyr 1 and the brahmaputra basin the highest overall rate of denudation 688 mm kyr 1 relationships between denudation rates and a range of morphometric hydrologic and climatic variables are investigated through correlation and regression analysis morphometric variables such as mean local relief are accurately calculated for large basins for the first time by using the national geophysical data center 10 minute topographic database variables expressing basin relief characteristics and runoff are found to be most strongly associated with both mechanical and chemical denudation rates with more than 60 of the variance in total denudation being accounted for by basin relief ratio and runoff basin area runoff variability and mean temperature however are only weakly associated with rates of denudation although direct comparisons cannot be made it appears that rates of basin denudation derived from present day mass flux estimates are not overall significantly different from estimates of long term rates based on sediment volume and thermochronologic data it therefore appears that the key factors identified as controlling denudation rates here are also applicable to the geological time spans relevant to the interaction between tectonic and denudational processes

holocene paleoecological changes and agro pastoral impact on the la narce du beage mire massif central france a paleoecological study macrofossils pollen cryptogam spores non pollen palynomorphs was performed to investigate environmental changes recorded on the peat deposits of the la narce du beage m