landslides and climate change in the italian dolomites since the late glacial abstract the paper deals with the relationship between the temporal occurrence of landslides and climatic changes in the italian dolomites since the late glacial after an introduction on the state of the art with particular reference to the alpine region the results of recent investigations in the two study sites are illustrated at cortina d ampezzo several landslides were dated mainly by the radiocarbon method the most ancient landslide event there involved large rock slides which affected the dolomitic slopes following the withdrawal of glaciers after the last glacial maximum lgm and also slides and flows mainly occurring in pelitic materials of the valley floors from 13 000 to 10 000 cal bp a later series of flows occurred between 5500 and 2500 cal bp in the upper badia valley alta badia the most ancient events go back to 10 000 and 9000 cal bp and correspond with earth flows that followed vast rotational slides affecting the bedrock up to a depth of about 50 m more recent earth flows involving more modest amounts of material took place between 6500 and 2300 cal bp by analysing the dates from the two study areas it was possible to correlate the recorded increase of landslide activity with the climatic changes occurring at the boundary between the late glacial and the holocene and between the atlantic and the subboreal and to compare the results with those derived from other european regions the types and causes of landslides taking place in these two periods were substantially different reflecting the different morphoclimatic conditions that existed in the two areas when these mass movements were triggered finally notwithstanding the importance of non climatic causes such as geological structural factors and possible human influences it is concluded that many of the dated landslides can be considered as indicators of climatic change

aeolian dust in europe african sources and european deposits abstract a conceptual model is presented for the provenance and dispersal patterns of small dust that falls on europe generally its sources are in north africa and it is distributed across all europe several key sources can be distinguished sahelian dust comes largely from the old lake chad region this is a clay rich unimodal material saharan dust comes from the great sand sheets it contains small monomineralic particles and may have a bimodal size range three simple deposition zones can be recognised a d1a zone where sufficient dust is deposited to form a discrete soil layer not well classified as a rendoll in the extreme south of europe a d1b zone where the airborne dust simply provided a silty admixture to soil systems across middle europe and a northern zone d1c where the dust is a fugitive cloud but very occasionally forms noticeable deposits two particle formation methods can be noted particle control in sahelian dust is via the sedimentation in the original lake this gives an open structure which can be modelled using a simple monte carlo approach the open structure ensures that only small particles are produced size control is via particle packing a chipping mechanism can produce fine quartz particles from sandy deserts the aeolian energy is by and large not sufficient to cause major impact fracturing but small mineral chips can be produced in the small dust size fine and very fine silt which go into high level suspension and travel to europe and beyond the saharan material can have a wider more variable size distribution than the sahelian material the canary islands loess is largely sahelian material the cape verde islands deposits from the nearby sandy regions are saharan deposits large dust has fallen on europe and produced widespread loess deposits large dust is essentially an in continent deposit small dust comes from outside from africa

tracking long term human impacts on landscape vegetal biodiversity and water quality in the lake aydat catchment auvergne france using pollen non pollen palynomorphs and diatom assemblages palaeoenvironmental studies allow the assessment of long term human climate environmental interactions and furnish valuable tools for the sustainable management of lacustrine ecosystems a good example is the multi proxy study of lake aydat s 19 m sedimentary core previous research revealed the role of climate and human activities on lake sedimentation and identified two sedimentary units 6700 200 to 3180 90 and 1770 60 cal yr bp to present separated by an erosive mass wasting deposit lavrieux et al 2013a pollen non pollen palynomorphs e g fungal and algal spores rotifer resting eggs and diatom based trophic reconstructions have been used to track the impacts of past land use on landscape evolution vegetal biodiversity and water quality palaeoenvironmental data were also compared with local archaeo historical datasets which allowed refined landscape reconstructions especially for late antiquity the results obtained demonstrate that even neolithic and bronze age human activities between ca 4600 and 4300 cal yr bp and between ca 3900 and 3500 cal yr bp had a discernible influence on catchment vegetation and lacustrine trophic dynamics of lake aydat underlining the vulnerability of the ecosystem recurrent and complex models of past vegetation changes phases of water nutrient over enrichment and lake resilience were identified and related to grazing activities but also to land use practises which have been overlooked in auvergne such as mountain agriculture and hemp retting

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

characterization and quantification of holocene colluvial and alluvial sediments in the valdaine region southern france this study presents a holocene sediment budget for the valdaine region located at the edge of the southern french pre alps holocene colluvial and alluvial deposition are quantified based on existing and new field data average sediment thickness values were calculated for different landscape units and available chronological data were used to make a time differentiated sediment budget total holocene colluvial deposition in the valdaine 334 km2 amounts 167 106 m3 while alluvial deposition in the roubion and jabron catchments in total 610 km2 including their catchment upstream the valdaine amounts 177 106 m3 especially colluvial deposition is high 0 75 106 g m2 compared with other catchments three major deposition periods 8500 2000 bc 700 bc ad 800 and ad 1200 2000 and two periods of relative hillslope stability with local fluvial incision 2000 700 bc and ad 800 1200 set the framework for a time differentiated sediment budget results show that depositional phases relate to intense

holocene optimum events inferred from subglacial sediments at tschierva glacier eastern swiss alps abstract this study investigates the subglacial sedimentary archive at tschierva glacier eastern swiss alps subfossil wood remains found at the retreating glacier tongue indicate that their emergence results from recent transport from an upvalley basin a confluence basin like structure was found to exist by georadar measurements underneath the present glacier in combination with high resolution age determinations based on dendrochronology and radiocarbon dating it is implied that a retreated tschierva glacier allowed vegetation growth and sediment accumulation in that basin three periods of glacier recession were detected which occurred around 9200 cal yr bp from 7450 to 6650 cal yr bp and from 6200 to 5650 cal yr bp these periods are called holocene optimum events hoe accordingly an equilibrium line rise 220 m compared to the reference period from 1960 to 1985 was inferred from digital elevation models of former glacier extents since glacier mass balance depends on summer june july august temperature and precipitation an equilibrium line altitude ela rise of 220 m implies a summer temperature increase of about 1 8 c assuming unchanged precipitation during the dated hoe alternative calculations point to probable temperature increase in a broad interval between 1 0 c taking into account a precipitation change of 250 mm a to 2 5 c with 250 mm a precipitation change supporting earlier paleotemperature estimates it is proposed that higher mean summer insolation caused a stronger seasonality during the mid holocene as compared to late holocene conditions

are mid latitude slopes sensitive to climatic oscillations implications from an early holocene sequence of slope deposits and buried soils from eastern germany abstract on a straight slope within the lake catchment of kleiner tornowsee brandenburg germany a sequence of slope sediments has been deposited during the late glacial the early holocene and around cal 4 2 ka before today 800 500 and 300 years ago the chronology is based on 21 radiocarbon dates and 11 osl dates and a deposition model including the numerical data as well as stratigraphic information has been calculated with oxcal 4 1 a comparison of the woody taxa of charcoal particles n 566 embedded within the sediments with the known regional vegetation history confirmed the reliability of the dates according to the age volume and distribution the deposition of the early holocene sediments at ca 10 3 kyrs ca 9 5 kyrs and ca 8 2 to 7 7 kyrs before today strongly suggests an influence of known climatic deteriorations phases on geomorphologic processes cold and dry climatic conditions probably promoted wildfires in pinus dominated forests and therefore triggered the observed repeated slope instability in consequence mid latitude slope deposits provide a potential to reconstruct the geomorphological response to climatic events at a high spatial resolution in contrast the recorded mid to late holocene soil erosion phases on the slope have been triggered by land use activities apart from traditional environmental archives slope deposits provide valuable information about the vegetation and climate history

tripartite climate reversal in central europe 5600 5300 years ago abstract the history of variations in water level of lake constance as reconstructed from sediment and pollen analysis of a sediment sequence from the archaeological site of arbon bleiche 3 shows an abrupt rise in lake level dendrochronologically dated to 5375 yr ago 5320 yr relative to ad 1950 this event paralleled by the destruction of the neolithic village by fire provoked the abandonment of this prehistoric lake shore location established in the former shallow bay of arbon bleiche and was the last of a series of three episodes of successively higher lake level the first occurring at 5600 5500 cal yr b p the dendrochronologically dated rise event was synchronous with an abrupt increase in atmospheric 14 c this supports the hypothesis of an abrupt climate change forced by varying solar activity moreover the three successive episodes of higher lake level between 5600 and 5300 cal yr b p at arbon bleiche 3 coincided with climatic cooling and or changes in moisture conditions in various regions of both hemispheres this period corresponds to the mid holocene climate transition onset of the neoglaciation and suggests inter hemispheric linkages for the climate variations recorded at arbon bleiche 3 this mid holocene climate reversal may have resulted from complex interactions between changes in orbital forcing ocean circulation and solar activity finally despite different seasonal hydrological regimes the similarities between lake level records from lake constance and from jurassian lakes over the mid holocene period point to time scale as a crucial factor in considering the possible impact of climate change on environments

holocene climatic instability a prominent widespread event 8200 yr ago the most prominent holocene climatic event in greenland ice core proxies with approximately half the amplitude of the younger dryas occurred 8000 to 8400 yr ago this holocene event affected regions well beyond the north atlantic basin as shown by synchronous increases in windblown chemical indicators together with a significant decrease in methane widespread proxy records from the tropics to the north polar regions show a short lived cool dry or windy event of similar age the spatial pattern of terrestrial and marine changes is similar to that of the younger dryas event suggesting a role for north atlantic thermohaline circulation possible forcings identified thus far for this holocene event are small consistent with recent model results indicating high sensitivity and strong linkages in the climatic system

river response to rapid holocene environmental change evidence and explanation in british catchments macklin m g jones a f lewin j 2010 river response to rapid holocene environmental change evidence and explanation in british catchments quaternary science reviews 29 13 14 1555 1576 sponsorship welsh assembly government and the higher education funding council for wales for funding this study through its support of the centre for catchment and coastal research at aberystwyth university

tephrostratigraphy of the last 160 ka in western limagne france the geocler 1 core extracted from the clermont crater lake sediments and surface studies made at several localities north of clermont provided numerous stratigraphic environmental and chronological data tl and radiocarbon which allow us to present a chronostratigraphy of the limagne for the past 160 ka 118 ash falls have been recorded in the crater lake sediments of the clermont maar they demonstrate that a basaltic phreatic activity developed along the western fault scarp of the limagne between 160 and 70 ka after which began the chaine des puys activity moreover several acid eruptions occured between 160 and 40 ka from older dryas to atlantic between 15 and 7 ka fourteen ash falls occured and in some cases the source volcanoes have been identified these include puy de la nugere puy de dome puy chopine kilian crater and puy de pariou which contribute mainly to the local tephra succession prospects for further prehistoric research in volcanic areas are outlined

natural oil slicks in the gulf of mexico visible from space natural oil seepage in the gulf of mexico causes persistent surface slicks that are visible from space in predictable locations a photograph of the sun glint pattern offshore from louisiana taken from the space shuttle atlantis on may 5 1989 shows at least 124 slicks in an area of about 15 000 km2 a thematic mapper tm image collected by the landsat orbiter on july 31 1991 shows at least 66 slicks in a cloud free area of 8200 km2 that overlaps the area of the photograph samples and descriptions made from a surface ship from aircraft and from a submarine confirmed the presence of crude oil in floating slicks the imagery data show surface slicks near eight locations where chemosynthetic communities dependent upon seeping hydrocarbons are known to occur on the seafloor additionally a large surface slick above the location of an active mud volcano was evident in the tm image in one location the combined set of observations confirmed the presence of a flourishing chemosynthetic community active seafloor oil and gas seepage crude oil on the sea surface and slick features that were visible in both images we derived an analytical expression for the formation of floating slicks based on a parameterization of seafloor flow rate downstream movement on the surface half life of floating oil and threshold thickness for detection applying this equation to the lengths of observed slicks suggested that the slicks in the atlantis photograph and in the tm image represent seepage rates of 2 2 30 m3 1000 km 2 d 1 and 1 4 18 m3 1000 km 2 d 1 respectively generalizing to an annual rate suggests that total natural seepage in this region is of the order of at least 20 000 m3 yr 1 120 000 barrels yr 1

variations in trace metal and halogen ratios in magmatic gases through an eruptive cycle of the pu u o o vent kilauea hawaii july august 1985 particle and gas samples were obtained before and after eruptive episode 35 in july and august 1985 at the fuming pu u o o vent kilauea volcano hawaii the sampling system employed consisted of a particle filter followed by four sup 7 lioh treated filters to collect acidic gases the filters were analyzed using instrumental neutron activation analysis inaa the results indicate that br cl and re cl ratios do not fluctuate through an eruption cycle but the f cl f br and metal cl ratios in and cd do change through the cycle an inverse relationship between f cl and metal cl was observed the changes are probably due to influxes of relatively undegassed magma during the repose period releasing fume with lower f cl f br and higher metal cl ratios as the magma in the pu u o o conduit gradually degasses either before or several days after an eruptive episode f cl and f br ratios increase and the metal cl ratios decrease one sample collected on july 24 two days before eruptive episode 35 did not follow this general trend this can be explained by a gas pulse from a deeper less degassed portion of magma making its way to the top of the conduit

sensitivity of west and central european river systems to environmental changes during the holocene a review abstract sediment deposition in floodplains is an essential part of the sediment dynamics of a catchment these sediment dynamics can vary largely on a holocene time scale under the influence of driving forces such as land use and climatic variations in this paper we review the holocene floodplain sediment deposition history of rivers in west and central europe with special attention to the influence of climate and land use variability during the early holocene preboreal to atlantic period most floodplains were rather stable with limited floodplain aggradation after this initial phase of relative stability sedimentation rates increase during the middle and late holocene with often the most important deposition phase during the last 1000 to 2000 a the start of the increase in sedimentation varies spatially with an earlier start in the west france germany then in the east poland belarus ukraine while there are also local differences between regions which are settled early e g loess regions compared to later settled regions the sedimentation history of most floodplains can be linked to the local land use history while influence of climatic variations on floodplain aggradation is often reported to be of minor importance processes related to bedload are often reported to be more influenced by climatic events relationships between the driving forces and the sediment history are mainly based on synchronicity and there is seldom proof for a direct causal relationship future research should focus on a system based approach integrating the floodplain deposition in the entire sediment dynamics which includes also erosion colluvial deposition and export main research questions that need further attention include integration of system based concepts like landscape connectivity and buffering effects and also the assessment of the individual contribution of land use changes and climatologic variations on the sediment dynamics detailed sediment budget studies combined with modeling studies can make an important contribution to the understanding of floodplain sediment dynamics

multicentury glacier fluctuations in the swiss alps during the holocene subfossil remains of wood and peat from six swiss glaciers found in proglacial fluvial sediments indicate that glaciers were smaller than the 1985 reference level and climatic conditions allowed vegetation growth in now glaciated basins an extended data set of swiss glacier recessions consisting of 143 radiocarbon dates is presented to improve the chronology of glacier fluctuations a comparison with other archives and dated glacier advances suggests 12 major recession periods occurring at 9850 9600 93008650 85508050 77007550 74506550 61505950 57005500 52004400 43003400 28002700 21501850 14001200 cal yr bp it is proposed that major glacier fluctuations occurred on a multicentennial scale with a changing pattern during the course of the holocene after the younger dryas glaciers receded to a smaller extent and prolonged recessions occurred repeatedly culminating around 7 cal kyr bp after a transition around 6 cal kyr bp weak fluctuations around the present level dominated after 3 6 cal kyr bp less frequent recessions interrupted the trend to advanced glaciers peaking with the prominent little ice age this trend is in line with a continuous decrease of summer insolation during the holocene

fluvial system evolution and environmental changes during the holocene in the mue valley western france geomorphological and palaeoenvironmental research on holocene sedimentation in the mue valley provides evidence for fluvial system changes related to climate and human activities in normandy a poorly studied area of the paris basin the 24 km long valley bottom has been investigated through a systematic survey it shows an original longitudinal sedimentary pattern in relation with valley morphology and local geological controls minerogenic tufaceous and peaty deposits provide opportunities for multi proxy analyses and radiocarbon dating control sedimentation began around 9500 14c bp with silt deposition in a meandering system the boreal and the lower atlantic periods 8500 6000 14c bp were mainly characterized by unlithified calcareous tufa locally these deposits are very thick 7 to 13 m the tufa formed barrages across the valley bottom providing an autogenic control on upstream sedimentation during the upper atlantic period 6000 4700 14c bp the valley experienced a decrease in calcareous sedimentation and the development of organic deposits at the beginning of the subboreal 4700 3500 14c bp peat deposits expanded especially behind the tufa barrages the valley bottom was characterized by large marshy areas whereas the regional vegetation was progressively modified by human activities at the end of the subboreal 3300 3000 14c bp the infilling of the valley by calcareous silt was caused by an increase of river activity related to climatic and land use changes from the iron age and gallo roman periods 2800 1700 14c bp the valley bottom was filled by silty overbank deposits related to an increase of soil erosion the slopes and river system were once again coupled and the fluvial system functioned as a continuum from upstream to downstream the alluvial record of the mue valley reflects a broad regional pattern of environmental changes but presents particular features which highlight the need of longitudinal studies to take into account spatial and temporal discontinuities of holocene hydro sedimentary systems even in small order valleys

climate change versus land management in the po plain northern italy during the bronze age new insights from the vp vg sequence of the terramara santa rosa di poviglio abstract the sedimentary infilling of the moat surrounding the villaggio piccolo of the terramara santa rosa di poviglio was analysed in order to obtain palaeoenvironmental inferences from sediments and pollen assemblage the high resolution stratigraphic sequence preserves evidence of the environmental changes that occurred in the po plain in northern italy during the late holocene our interdisciplinary approach permitted to study climatic and anthropic contributions to the environmental changes in this region the relationships between these changes and land use changes were investigated focussing on adaptive strategies of the terramare people during the middle and recent bronze ages 1550 1170 yr bc the terramare are archaeological remains of banked and moated villages located in the central alluvial plain of the po river the terramara of santa rosa consists of two adjoining settlements villaggio grande and villaggio piccolo the moat that separates the two parts of the site is c 23 m large and reaches a maximum depth of 4 m from the extant ground level the stratigraphic sequence vp vg exposed by archaeological excavation inside the moat was sampled for pedosedimentary thin section and pollen analyses chronology is based on archaeological evidence stratigraphic correlations and radiocarbon dating pedosedimentary features and biological records pollen of aquatics and algal remains demonstrate that shallow water probably subjected to seasonal water level oscillations has always been present in the moat in the lower units of the sequence the laminations indicate standing water while occurrence of reworked pollen testified the supply of sediments to the plain from catchment zones located in the apennine open vegetation was widespread economy was based on wood management fruit collection on the wild or from cultivated woody plants crop fields with a fairly diversified set of cereals especially increasing in variety during dryness or phases of water crisis probably grapevines were cultivated near the moat where the wet habitat was favourable to the growing of wild plants the extraordinary high resolution of this sequence makes visible the management of woods including coppicing at the middle bronze and early recent bronze ages the economy of santa rosa di poviglio should have been probably less based on animal breeding than it was in the other terramare villages already studied for pollen this research also confirms the chronological correspondence between an environment stressed by dry conditions and the collapse of the terramare civilization

visualization of lidar derived relief models for detection of archaeological features abstract this paper presents visualisation techniques of high resolution digital elevation models dems for visual detection of archaeological features the methods commonly used in archaeology are reviewed and improvements are suggested one straightforward technique that has so far not been used in archaeology the shift method is presented the main purpose of this article is to compare and evaluate different visualisation methods two conclusions have been reached where a single method must be chosen for printing or producing digital images for non professionals the use of sky view factor or slope gradient is endorsed both presented in greyscale otherwise interpreters should choose different techniques on different terrain types shift on flat terrain sky view factor on mixed terrain slope gradient on sloped terrain and sky view factor preferably as a composite image with slope gradient on rugged terrain

6700 yr sedimentary record of climatic and anthropogenic signals in lake aydat french massif central a 19 meters long sedimentary record that was retrieved in lake aydat french massif central covers the last 6700 yrs at a high resolution a multi proxy approach density magnetic susceptibility xrf rock eval analyses pollen and non pollen palynomorphs analyses and historical archives study was used to characterise and tentatively propose a model of the sedimentation the important deposition rate results from the narrow and incised fluvial valley dammed by a lava flow ca 8550 years ago two contrasted periods of sedimentation 6700 200 3180 90 cal bp and 1770 60 cal bp now are characterized the lower unit mid holocene displays a fine and regular lamination and holds a single major flood deposit this unit is capped by an erosive mass wasting deposit triggered ca 1770 60 cal bp the upper unit late holocene is made of organic rich and fine grained faintly laminated sediment with numerous interbedded flood deposits 56 events and layers resulting from blooms of diatoms the sedimentation was principally controlled by climatic forcings solar activity until ca 1100 cal bp accompanied by detritic events linked to human activities around the lake then a more detrital input attested by numerous and recurrent flood deposits can be linked to the intensification of a persistent anthropogenic impact on the catchment two phases of lake eutrophication are highlighted a first phase between 1200 1130 cal bp as a result of increased anthropogenic pressure and the current phase that could have started ca 150 cal bp

circum mediterranean fire activity and climate changes during the mid holocene environmental transition 8500 2500 cal bp a mid to late holocene synthesis of fire activity from the mediterranean basin explores the linkages among fire climate variability and seasonality through several climatic and ecological transitions regional fire histories were created from 36 radiocarbon dated sedimentary charcoal records available from the global charcoal database during the mid holocene thermal maximum around 7500 4500 cal bp charcoal records from the northern mediterranean suggest an increase in fire while records from the southern mediterranean indicate a decrease associated with wetter than present summers a north south partition between 40 and 43 n latitude is apparent in the central and western mediterranean relatively abrupt changes in fire activity are observed c 5500 5000 cal bp records of holocene fire activity appear sensitive to both orbitally forced climate changes and shorter lived excursions which may be related to north atlantic cold events possibly modulated by an nao like climate mechanism in cases wh

high resolution topography for understanding earth surface processes opportunities and challenges abstract in the last decade a range of new remote sensing techniques has led to a dramatic increase in terrain information providing new opportunities for a better understanding of earth surface processes based on geomorphic signatures technologies such as airborne and terrestrial lidar light detection and ranging to obtain high resolution topography have opened avenues for the analysis of landslides hillslope and channellization processes river morphology active tectonics volcanic landforms and anthropogenic signatures on topography this review provides an overview of the recent flourishing literature on high resolution topographic analyses underlining their opportunities and critical issues such as their limitations the goal is to provide answers to questions such as what kind of processes can be analyzed through high resolution topographic data and how to do it the review focuses on two different environments natural and engineered landscapes in both contexts high resolution topography offers opportunities to better understand geomorphic processes from topographic signatures particular attention is given to engineered landscapes in which the direct anthropic alteration of processes is significant the last part of the review discusses future challenges

the history of human induced soil erosion geomorphic legacies early descriptions and research and the development of soil conservation a global synopsis abstract this paper presents a global synopsis about the geomorphic evidence of soil erosion in humid and semihumid areas since the beginning of agriculture historical documents starting from ancient records to data from the mid twentieth century and numerous literature reviews form an extensive assortment of examples that show how soil erosion has been perceived previously by scholars land surveyors farmers land owners researchers and policy makers examples have been selected from ancient greek and roman times and from central europe southern africa north america the chinese loess plateau australia new zealand and easter island furthermore a comprehensive collection on the development of soil erosion research and soil conservation has been provided with a particular focus on germany and the usa geomorphic evidence shows that most of the agriculturally used slopes in the old and new worlds had already been affected by soil erosion in earlier prehistoric times early descriptions of soil erosion are often very vague with regard to the roman times geomorphic evidence shows seemingly opposing results ranging from massive devastation to landscapes remaining stable for centuries unfortunately historical documentation is lacking in the following centuries historical records become more frequent and more precise and observations on extreme soil erosion events are prominent sometimes they can be clearly linked to geomorphic evidence in the field the advent of professional soil conservation took place in the late eighteenth century the first extensive essay on soil conservation known to the western world was published in germany in 1815 the rise of professional soil conservation occurred in the late nineteenth and early twentieth centuries soil remediation and flood prevention programs were initiated but the long term success of these actions remains controversial in recent years increasing interest is to recover any traditional knowledge of soil management in order to incorporate it into modern soil conservation strategies the study shows that local and regional variations in natural settings cultural traditions and socioeconomic conditions played a major role for the dynamics and the rates of soil erosion on a long term perspective geomorphic evidence and historical sources can often complement each other but there should be also an awareness of new pitfalls when using them together

structure and origin of holocene cold events abstract the present interglacial the holocene spans the period of the last 11 700 years it has sustained the growth and development of modern society the millennial scale decreasing solar insolation in the northern hemisphere summer lead to northern hemisphere cooling a southern shift of the intertropical convergence zone itcz and a weakening of the northern hemisphere summer monsoon systems on the multidecadal to multicentury scale periods of more stable and warmer climate were interrupted by several cold relapses at least in the northern hemisphere extra tropical area based on carefully selected 10 000 year long time series of temperature and humidity precipitation as well as reconstructions of glacier advances the spatiotemporal pattern of six cold relapses during the last 10 000 years was analysed and presented in form of a holocene climate atlas hoclat see http www oeschger unibe ch research projects holocene atlas a clear cyclicity was not found and the spatiotemporal variability of temperature and humidity precipitation during the six specific cold events 8200 6300 4700 2700 1550 and 550 years bp was very high different dynamical processes such as meltwater flux into the north atlantic low solar activity explosive volcanic eruptions and fluctuations of the thermohaline circulation likely played a major role in addition internal dynamics in the north atlantic and pacific area including their complex interaction were likely involved

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

landslides as a geomorphological proxy for climate change a record from the dolomites northern italy abstract this study investigates the relationships between climate changes and hillslope evolution in the dolomites eastern alps italy during the late quaternary with particular attention paid to landslide processes the basic premise is that modifications in landslide frequency may be interpreted as changes in the hydrological conditions of slopes which are in turn controlled by climate after the statistical analysis of a data set composed of 73 conventional radiocarbon ages obtained from 24 landslides four periods of enhanced landsliding have been identified i from 10 700 to 8400 cal bp between younger dryas and the preboreal ii from 8200 to 6900 cal bp during the older atlantic iii from 5800 to 4500 cal bp between atlantic and subboreal and iv from 4000 to 2100 cal bp between subboreal and subatlantic these periods have been compared with different lateglacial and holocene paleoclimatic records to check the correspondence between periods of enhanced landslide activity and cold and humid spells recognized at different spatial scales as the records show in the study areas slope instability processes can be considered geomorphological indicators of climatic changes and to a certain extent reliable proxies of environmental evolution

mid holocene emergence of a low frequency millennial oscillation in western mediterranean climate implications for past dynamics of the north atlantic atmospheric westerlies the nature and tempo of holocene climate variability is examined in the record of forest vegetation from western mediterranean marine core md95 2043 episodes of forest decline occurred at 10 1 9 2 8 3 7 4 5 4 4 5 and 3 7 2 9 cal ka bp and between 1 9 cal ka bp and the top of the record 1 3 cal ka bp wavelet analysis confirms a 900 yr periodicity prior to and during the early holocene and the dominance of a 1750 yr periodicity after 6 cal ka bp the 900 yr periodicity has counterparts in numerous north atlantic and northern hemisphere palaeoclimate records and in solar irradiance proxies 14c and 10be and may relate to a sun climate connection during the early holocene comparisons between the md95 2043 forest record and strategically located records from morocco iceland norway and israel suggest that the 1750 yr mid to late holocene oscillation reflects shifts between a prevailing strong and weak state of the zonal flow with impacts similar to the positive and negative modes of th

fragility of western mediterranean landscapes during holocene rapid climate changes abstract in this paper we explore the evidence for holocene rapid climate changes rccs in western mediterranean records examining similarities and differences in the timing and nature of impacts on different components of the natural environment vegetation fluvial and coastal sedimentation fire activity soil formation marine lacustrine and fluvial archives of the western mediterranean iberian peninsula and northwest africa provide evidence for both pervasive millennial scale climatic variability and abrupt decadal to centennial scale transitions we focus in particular on three rccs characterised by high latitude cooling glacier advances and north atlantic ice rafting events the mid holocene rcc interval 6 5 cal ka bp the late holocene rcc interval 3 5 2 5 cal ka bp and the historical rcc interval known as the little ice age lia 1300 1950 ad evidence from multiple records indicates wide ranging impacts of rccs in the western mediterranean region the three rcc intervals were characterised however by contrasting hydrological situations in the western mediterranean with prevailing dry conditions including marked aridification events during the rcc intervals 6 5 and 3 5 2 5 cal ka bp and prevailing or recurrent wet conditions during the lia we examine issues of proxy sensitivity in palaeoecological and geomorphological records and evaluate examples of contrasting geomorphological responses to regional climatic triggers between humid and semi arid sectors of the western mediterranean finally we consider the long term sensitivity of the region to rapid climate change the role of threshold changes and the extent to which this region represents a fragile landscape

quantitative analysis of climate versus human impact on sediment yield since the lateglacial the sarlieve palaeolake catchment france minimum rates of solid ssy and dissolved dsy sediment yield sy were evaluated in t km2 per yr from sediments stored in the sarlieve palaeolake french massif central for seven phases of the lateglacial and holocene up to the seventeenth century the catchment 29 km2 mainly formed of limestones and marls is located in an area rich in archaeological sites in the massif central the respective impacts of human activities and climate on sy were compared by quantification of human settlements through archaeological survey and palynological data during the lateglacial and early holocene up to about 7500 yr cal bp variations in ssy and dsy rates were mainly related to climate change with higher rates during colder periods younger dryas and preboreal and lower rates during warmer periods bolling allerod and boreal however cf1 tephra fallout induced a sharp increase in sy during the allerod during the middle and late holocene after 7500 yr cal bp ssy and dsy greatly increased by factors of 6 5 and 2 8 respectively particularly during the final neolithic at about 5300 yr cal bp when the climate became cooler and more humid after this date at least 75 of the ssy increase and more than 90 of the dsy increase resulted from human activities but ssy rates showed little variation during protohistoric and historic times up to the seventeenth century ssy and dsy rates and dsy ssy ratio indicate that catchment soils began to form during the lateglacial and preboreal thickened considerably during the boreal and atlantic finally thinning rejuvenation mainly as the result of human induced erosion during the sub boreal and sub atlantic increased mechanical erosion during the late holocene also induced an increase in chemical erosion

the history of soil erosion and fluvial deposits in small catchments of central europe deciphering the long term interaction between humans and the environment a review abstract during the last few decades many case studies focused on the dynamics of fluvial systems in response to hillslope erosion land use impact and climate changes this paper will review the current state of knowledge of the dynamics of past soil erosion and gullying in small catchments

origin and holocene geomorphological evolution of the landslide dammed basin of la narse de la sauvetat massif central france this work is the first geomorphological analysis of la narse de la sauvetat a hydromorphic basin located in the southern limagne plain french massif central which had never been studied despite its great palaeoenvironmental interest we explore the potential of its sedimentary archives to provide valuable data on holocene geomorphic dynamics and their sensitivity to local and regional hydro climatic changes in order to characterize the nature and the morphostratigraphic and pedosedimentary evolution of the basin we used an integrative approach involving geomorphological mapping hand auger stratigraphic cross sections topographic analysis based on lidar data and stereophotogrammetric reconstruction geophysical prospection and radiocarbon dating results revealed a palaeotopography fossilized under 6 m of sedimentary infilling with a clear shift from fluvial to hydromorphic conditions circa 2800 cal bce separated by a level with colluvial and lacustrine features a detailed analysis of the eastern border of the basin also suggests the existence of a former open valley in place of the current closed depression now locked in by a topographic threshold forming a dam the sedimentary aggradation of the basin started with an alluvial phase during the upper pleistocene and probably continued into the middle and late holocene consistently with regional alluvial dynamics in the early subboreal a massive landslide occurred on the western slopes of the puy de corent volcanic plateau thereby damming the valley and forming a closed depression this episode coincided with the mid holocene climatic shift and an associated phase of slope instability and increased landslides in western europe due to changing climatic conditions this depression evolved into a hydromorphic basin with several high energy hydro sedimentary episodes after 2800 cal bce however hydro sedimentary conditions gradually became more stable towards the late holocene around 500 cal ce the drainage deteriorated towards palustrine conditions and caused the formation of a marsh and its consequent evolution into a shallow lake throughout the middle ages this lake was drained in the late xviiith century the long term sedimentary record of la narse de la sauvetat sensitive to climatic instability periods of the middle holocene makes this landslide dammed basin a valuable site with an important potential to further development of palaeoenvironmental and geoarchaeological studies

mid holocene cluster of large scale landslides revealed in the southwestern alps by 36cl dating insight on an alpine scale landslide activity abstract although it is generally assumed that the internal structure of a slope e g lithology and rock mass properties inherited faults and heterogeneities etc is preponderant for the progressive development of large scale landslides the ability to identify triggering factors responsible for final slope failures such as glacial debuttressing seismic activities or climatic changes especially when considering landslide cluster at an orogen scale is still debated highlighting in this study the spatial and temporal concordant clustering of deep seated slope failures in the external southwestern alps we discuss and review the possible causes for such wide spread slope instabilities at both local and larger alpine scale high resolution field mapping coupled with electrical resistivity tomography first allows establishing an inventory of large landslides in the southwestern alps determining their structural model precising their depth limit 100 200 m as well as the involved rock volumes 10 7 m 3 we show that they developed in the same geostructural context of thick mudstone layers overlain by faulted limestone and followed a block spread model of deformation that could evolve in rock collapse events cosmic ray exposure dating cre using both 36 cl and 10 be in coexisting limestone and chert respectively has been carried out from the main scarps of six deep seated landslides dsl and leads to landslide failure cre ages ranging from 3 7 to 4 7 ka they highlighted i mainly single and fast ruptures and ii a possible concomitant initiation with a main peak of activity between 3 3 and 5 1 ka centered at ca 4 2 ka because this region was not affected by historical glaciations events landslide triggering by glacial unloading can be excluded the presented data combined with field observations preferentially suggest that these failures were climatically driven and were most likely controlled by high pressure changes in the karstic medium in effect the chronicle of failure ages is concomitant to a well known climatic pulse the 4 2 ka climate event characterized by intense hydrological perturbations associated to the heaviest rainfall period of the entire holocene despite requiring further investigations and discussions the dating of numerous events across the entire alps during the middle holocene period suggests a potential synchronous triggering of several large scale gravitational failures induced by the mid holocene climatic transition

detection of subtle tectonic geomorphic features in densely forested mountains by very high resolution airborne lidar survey abstract despite successes elsewhere in the world 2 m resolution dems from a standard airborne lidar survey failed to detect small tectonic geomorphic features in densely forested high relief mountains of central japan our new 0 5 m dems from an unprecedentedly high resolution lidar survey along the neodani fault now reveal a number of previously unknown fault scarps as well as other hidden geomorphic features the survey achieves a ground return density of 6 2 m 2 out of a total shot density of as much as 12 7 m 2 the main factor to gain sufficient ground returns in unfavorable conditions is a large side lap of 70 between flight swaths which means that any specific area in the target zone is scanned three or more times from different angles evaluation of dems with resolution from 0 25 to 10 m assures that a 0 5m resolution lidar dem is necessary for the detection of subtle tectonic breaks another key factor for complete detection of small tectonic geomorphic features is the application of a recently developed dem visualization red relief image map rrim which allows mapping of all the small features with various sizes orientations and morphology overcoming major drawbacks of classic dem visualizations a very high resolution lidar survey aided with rrim visualization as used in this study provides a more reliable approach for the detailed mapping of slight active fault traces hidden under dense vegetation