temperatures at the base of the laurentide ice sheet inferred from borehole temperature data 1 we use temperature profiles from 4 deep 1600 m boreholes across canada to determine ground surface temperature histories gsth s through and after the last glacial maximum lgm inversion yields the temperature history at the base of the glacier and the surface temperature evolution after the glacial retreat the results indicate geographic differences in basal temperature history across the ice sheet during the last glacial maximum temperatures at the base of the ice sheet were lower in eastern canada at the southeastern edge of the glacier than in central canada southwest of the glacier center at all sites basal temperatures were above the melting point of ice during and after the lgm which may explain the highly unstable character of the ice sheet the gsth s are consistent with information on the history of the laurentide ice sheet and provide quantitative constraints on glacier flow dynamics

sediment delivery after a wildfire we use a record of sedimentation in a small reservoir within the cerro grande burn area new mexico to document postfire delivery of ash other fine grained sediment carried in suspension within floods and coarse grained sediment transported as bedload over a five year period ash content of sediment layers is estimated using fallout 137 cs as a tracer and ash concentrations are shown to rapidly decrease through a series of moderate intensity convective storms in the first rainy season after the fire over 90 of the ash was delivered to the reservoir in the first year and ash concentrations in suspended sediment were negligible after the second year delivery of the remainder of the fine sediment also declined rapidly after the first year despite the occurrence of higher intensity storms in the second year fine sediment loads after five years remained significantly above prefire averages deposition of coarse grained sediment was irregular in time and was associated with transport by snowmelt runoff of sediment stored along the upstream channel during short duration summer floods coarse sediment delivery in the first four years was strongly correlated with snowmelt volume suggesting a transport limited system with abundant available sediment transport rates of coarse sediment declined in the fifth year consistent with a transition to a more stable channel as the accessible sediment supply was depleted and the channel bed coarsened maximum impacts from ash and other fine grained sediment therefore occurred soon after the fire whereas the downstream impacts from coarse grained sediment were attenuated by the more gradual process of bedload sediment transport

insolation values for the climate of the last 10 million years new values for the astronomical parameters of the earth s orbit and rotation eccentricity obliquity and precession are proposed for paleoclimatic research related to the late miocene the pliocene and the quaternary they have been obtained from a numerical solution of the lagrangian system of the planetary point masses and from an analytical solution of the poisson equations of the earth moon system the analytical expansion allows the direct determination of the main frequencies with their phase and amplitude numerical and analytical comparisons with the former astronomical solution ber78 are performed so that the accuracy and the interval of time over which the new solution is valid can be estimated the corresponding insolation values have also been computed this analysis leads to the conclusion that the new values are expected to be reliable over the last 5 ma in the time domain and at least over the last 10 ma in the frequency domain

ground surface temperature history in poland in the 16th 20th centuries derived from the inversion of geothermal profiles ground surface temperature gst history in poland was derived from the inversion of temperature depth profiles in over 20 wells temperature histories for the period 1500 a d through 1977 a d agree well with the instrumental record of the surface air temperature available for the last two centuries a statistical correlation of the reconstructed histories from the well temperature data with the instrumental record air temperature from the homogeneous warsaw series is high 0 8 functional space inversion fsi of the temperature data with depth shows that beginning in the early 19th century temperatures warmed by 0 9 0 1 c following a long period of colder climate before the last number could be a minimal as higher warming was calculated using a simple model based on surface temperature for the observational period homogenized warsaw surface temperature series lorenc 2000 and pom pre observational mean harris and chapman 1998 of 1 53oc below the 1951 1980 mean temperature level

the last glaciation of earth size and volume of ice sheets abstract the volume and size of the late glacial ice sheets in the northern hemisphere has been estimated based on geomorphic and chronostratigraphic data limited glacial extents during the late glacial maximum characterized both arctic canada and northern eurasia in contrast to the presence of the large laurentide scandinavian and devensian ice sheets to the south glacial maxima were not synchronous throughout the northern hemisphere for example the novaya zemlya ice sheet reached its maximum extent ca 39 000 bp approximately 20 000 years earlier than the maximum extent of the contiguous scandinavian ice sheet western and central siberia and the chukhui peninsula were marked by limited glaciation during the last glacial maximum although pre sartanian events were more extensive mountain glaciation in northeast asia was similarly restricted during the last glacial maximum spatial and dynamic characteristics of the last glaciation developed in response to climatic factors the establishment and strength of high pressure systems over siberia limited precipitation and glacier formation throughout northeastern eurasia

runoff and soil moisture as driving factors in suspended sediment transport of a small mid mountain mediterranean catchment abstract soil moisture conditions play a key role in runoff and sediment load dynamics in river catchments of contrasting ecosystems however the highly marked seasonality of mediterranean climate affects hydrological processes and sediment transport strongly as evapotranspiration determines a succession of wet transition and dry periods throughout a hydrological year this study examines results of soil moisture water and sediment fluxes during five hydrological years in a representative small mid mountain mediterranean catchment it aims to assess the sediment load contribution and its variability at different temporal scales precipitation runoff and suspended sediment load were calculated at annual seasonal and event scales to assess inter and intra annual variability a database with 45 events was used to identify the main controlling factors over sediment load thought bivariate relationships and an analysis of soil moisture discharge and discharge suspended sediment concentration hysteresis at the annual scale lithology land use and soil conservation structures characteristic of the catchment caused low values of sediment yield although inter annual rates varied by up to three orders of magnitude 0 08 to 11 86 t km 2 y 1 seasonal analysis of accumulated sediment load showed that 80 was generated during the autumn and winter seasons at the event scale streamflow and soil moisture were the controlling factors for the largest sediment load contributions the highest frequency of clockwise discharge suspended sediment concentration hysteresis revealed that most of the sediment was generated from nearby sources although the largest sediment loads were contributed under wet antecedent conditions as depicted by the soil moisture discharge hysteresis assessment

thermal effects of zechstein salt and the early to middle jurassic hydrothermal event in the central polish basin deep gas potential in the polish basin may factor significantly in european geopolitics and thermal effects can influence that outcome there and elsewhere deep 3 km 9843 ft well data from the kujawy area of the central polish basin reveal average geothermal gradient 36c km thermal conductivity of mesozoic strata k 2 29 w m k and present day heat flow q 82 4 mw m2 that is 3 less than that obtained using the entire borehole the extrapolated surface temperature 6 2c is in good agreement with temperatures during the weichselian glaciation the thermal conductivity of the upper permian zechstein 4 89 w m k is in good agreement with values from the north sea and northern germany steady state heat flow theory one dimensional 1 d predicts present day temperature 199c at the base of zechstein cap rock at 6 km 19 685 ft depth in kujawy this is reduced just more than 10c by low zechstein thermal gradients 16 8c km because of thermal refraction two dimensional and three dimensional models of zechstein salt pillows can significantly negate this cooling effect however such effects appear absent in the kujawy wells studied a widespread early to middle jurassic 195 175 ma hydrothermal event appears to have reached maximum in the kujawy area a 455c paleotemperature at 7 km 22 966 ft depth carboniferous is predicted by 1 d conductive heat transfer however geologic evidence does not support this result the discrepancy is reconciled by convective heat transfer with upward fluid flow 3 3 10 10 m s 10 8 10 10 ft s resulting in a maximum paleotemperature of 273c at 7 km 22 966 ft depth despite a paleoheat flow of 142 mw m2 the trend of intensity of the hydrothermal event correlates with the present day heat flow trend hydrothermal event sites are subparallel to the major northwest southeast structural and regional heat flow trend whereas other sites as close as 14 km 45 932 ft and without hydrothermal event are not the decay of the hydrothermal event is consistent with localized cylindrical plumes 10 km 32 808 ft radius that cool by conduction results suggest a long term 185 m y structural control on heat flow linear regression to vitrinite paleotemperatures yields a 185 ma jurassic surface temperature of approximately 21 3c that is approximately 13c higher than the present day temperature for warsaw poland the duration of maximum reservoir and source rock paleotemperature 50 m y is contrary to the kinetics of nitrogen and co2 producing wells equilibrium thermodynamics predicts approximately 60 methane for present day kujawy reservoirs with considerable uncertainty that should be removed by anticipated new deep drilling

palaeoclimate and structure the most important factors controlling subsurface temperatures in crystalline rocks a case history from outokumpu eastern finland summary the present work contributes to the study of heat transfer mechanisms in crystalline bedrock we present evidence from a thoroughly investigated case history in outokumpu eastern finland in the fennoscandian or baltic shield which shows that the subsurface temperature field is controlled by the thermal conductivity structure and downward diffusion of palaeoclimatic ground temperature variations the subsurface temperature profiles from three continuously cored boreholes 790 1 100 m deep were used for a detailed 2 d modelling of structural hydrogeological and palaeoclimatic effects on the subsurface temperature field the boreholes are situated in a subdued topography and they intersect early precambrian folded lithologies such as mica gneisses black schists skarn rocks quartzites and serpentinite talc rocks finitedifference techniques were used in the numerical solution of the heat and masstransport equations the 2 d models of thermal conductivity and hydraulic permeability that were compiled were based on an extensive set of data relating to geological structure in situ hydraulic permeability groundwater composition and thermal conductivity of drill core samples down to about 1 km depth it was found that the thermal effect of topographically driven groundwater convection is very small with peclet numbers typically of the order of 10 4 10 5 the effect of anisotropy of thermal conductivity was found to be one order of magnitude smaller than the effects of heatflow refraction in the inclined rock layers which produce horizontal components of heat flow density ranging from 15 to 5 mw m basal heat flow 35 mw m since the advective heat transfer could be neglected we tried to find a palaeoclimatic groundtemperature history that would explain the measured data first an inversion algorithm based on heat conduction in laterally homogeneous media was used for the reconstruction of palaeoclimatic ground temperature history but it yielded spurious results because of the strong 2 d conductivity effects the only means to reconstruct the past ground temperature changes was forward modelling using a conductive transient 2 d model with time dependent surface temperature variations the surface temperatures at different times between 100000 yr bp and the present and the basal heat flow density were varied in order to reach a reasonable fit between the modelled and measured borehole temperatures to reach this goal the ground temperature history must include the main climatic events during the last 100000 yr such as the last glacial epoch and the little ice age from about 1300 ad to 1700 ad followed by warmer temperatures in more recent times our results suggests that subsurface temperatures in conditions similar to those of the outokumpu case can yield a wealth of palaeoclimatic information when an appropriate approach for modelling heat transfer in the bedrock is chosen

geomorphological evolution of abandoned fields a case study in the central pyrenees abstract by means of geomorphological transects the evolution undergone by cultivated land after abandonment has been studied during the first years diffuse overland flow processes predominate while older fields seem more highly deteriorated incisions stone flows stone pavement the results confirm the important protection role of vegetable covering particularly scrub and the negative influence of soil uses grazing leads to periodic scrub burnings increasing surface stoniness and concentrated overland flow

human impacts on fluvial systems in the mediterranean region the long history of substantial human impacts on the landscape of the mediterranean region and their effects on fluvial systems is documented these effects have included impacts of deforestation and other land use changes agricultural terracing on a wide scale water transfers and irrigation schemes during the 20th century major changes were made directly to channels through channelisation construction of dams of various sizes and extraction of gravel and indirectly by reforestation these changes have caused a major phase of incision on some rivers runoff and soil erosion have been affected by types of crops and agricultural practices as well as by the varying extent of cultivation and grazing some recent agricultural practices involve wholescale relandscaping of the topography and alteration of surface properties of material the importance of analysing the connectivity within different land units and of the spatial position of human activity within a catchment is illustrated the analysis of connectivity is the key to understanding the variability of impact and the extent of propagation of effects

temperature trends over the past five centuries reconstructed from borehole temperatures for an accurate assessment of the relative roles of natural variability and anthropogenic influence in the earth s climate reconstructions of past temperatures from the pre industrial as well as the industrial period are essential but instrumental records are typically available for no more than the past 150 years therefore reconstructions of pre industrial climate rely principally on traditional climate proxy records each with particular strengths and limitations in representing climatic variability subsurface temperatures comprise an independent archive of past surface temperature changes that is complementary to both the instrumental record and the climate proxies here we use present day temperatures in 616 boreholes from all continents except antarctica to reconstruct century long trends in temperatures over the past 500 years at global hemispheric and continental scales the results confirm the unusual warming of the twentieth century revealed by the instrumental record but suggest that the cumulative change over the past five centuries amounts to about 1 k exceeding recent estimates from conventional climate proxies the strength of temperature reconstructions from boreholes lies in the detection of long term trends complementary to conventional climate proxies but to obtain a complete picture of past warming the differences between the approaches need to be investigated in detail

analysis of soil surface component patterns affecting runoff generation an example of methods applied to mediterranean hillslopes in alicante spain abstract spatial patterns of soil surface components vegetation rock fragments crusts bedrock outcrops etc are a key factor determining hydrological functioning of hillslopes a methodological approach to analyse the patterns of soil surface components at a detailed scale is proposed in this paper the methods proposed are applied to two contrasting semi arid mediterranean hillslopes and the influence of soil surface component patterns on the runoff response of the slopes was analysed a soil surface components map was derived from a high resolution photo mosaic obtained in the field by means of a digital camera rainfall simulation experimental data were used to characterise the hydrological behaviour of areas with a specific pattern of soil surface components by means of the parameters of the horton equation plot runoff data were extrapolated at the hillslope scale based on the soil surface component maps and their hydrological characterisation the results show that in both slopes runoff generation is concentrated up and downslope with a water accepting area in the centre of both slopes disrupting the hydrological connectivity at the slope scale this reinfiltration patch at the centre of the slope is related to the type of soil surface component and its spatial pattern herbaceous vegetation and on top rock fragments increase the infiltration capacity of soils at the centre of the slope in contrast embedded rock fragments rock outcrops as well as crusted surfaces located in the upper and lower slopes favour runoff generation in these areas in addition a general pattern of water contribution areas downslope is apparent on both slopes the south facing slope shows a higher hydrological connectivity and more runoff 55 of the surface of the south facing slope produces runoff at the end of a 1 hour rainfall event and 17 3 of the surface is covered by a runoff depth between 0 5 and 1 mm while on the north facing slope only 38 of the surface produces runoff under the same conditions longitudinal connectivity of runoff is higher at the south facing slope where more runoff generating surfaces appear and where the vegetation pattern favours the connectivity of bare areas

temporal distribution of suspended sediment transport in a mediterranean basin the lower tordera ne spain abstract suspended sediment dynamics are still imperfectly understood especially in areas of mediterranean climate with strong seasonal contrasts where few studies have been conducted the aim of this study is to analyze the variability in the suspended sediment load at different temporal scales within flood variability monthly seasonal and annual in the tordera river 894 km 2 located in northeastern spain suspended sediment samples were obtained during base flows q 3 5 m 3 s 1 and flood events q 3 5 m 3 s 1 the analysis of the variability in the suspended sediment is structured in two consecutive steps i the construction of statistical relations between suspended sediment concentrations c and discharge q and ii the application of those relations to assess the suspended sediment yield the results show that in a single event the sediment peak generally precedes the peak discharge following a clockwise hysteretic loop furthermore it was observed that the reduction in the suspended sediment concentrations in a sequence of events can be mainly associated with a phenomenon of sediment exhaustion the total amount of suspended sediment transported during a single flood is thus related to its duration and time during the year as well as to its magnitude at a seasonal scale the export of suspended sediment takes place in two phases i sediment preparation and ii sediment transfer and exhaustion during the latter phase the exhaustion of the sediment load is primarily related to the sequence of flood events at the annual scale the results show high inter annual variability according to the number of floods recorded yearly since almost all the suspended load is transported during those events

geothermal evidence of very low glacial temperatures on a rim of the fennoscandian ice sheet 1 the mean ground temperature as low as 10 c and the existence of more than 500 m thick permafrost during the last glacial are apparent from the analysis of deep borehole temperature profiles in north eastern poland the largest thickness of the permafrost and its survival deep into the holocene was restricted to a region known for its low terrestrial heat flow where the negative temperature gradient is observed in the uppermost 400 m we have shown that the profiles are consistent with warming from the glacial mean of 10 c to the holocene mean of 7 c 14 ka ago and to 8 c in the last 150 years

deglaciation of a soft bedded laurentide ice sheet we present a series of numerical reconstructions of the laurentide ice sheet during the last deglaciation 18 7 14c ka that evaluates the sensitivity of ice sheet geometry to subglacial sediment deformation these reconstructions assume that the laurentide ice sheet flowed over extensive areas of water saturated deforming sediment soft beds corresponding to the st lawrence lowland the great lakes region the western prairies of the u s and canada and the hudson bay and hudson strait regions sediment rheology is based on a constitutive law that incorporates experimental results from late wisconsin till deposited by the laurentide ice sheet which suggest only mildly nonlinear viscoplastic behavior by varying the effective viscosity of till we produced four reconstructions for the ice sheet during the last glacial maximum 18 14c ka and two reconstructions each of the ice sheet at 14 13 12 11 and 10 14c ka we also produced one reconstruction for 9 8 4 8 and 7 14c ka reconstructions that assume a low effective viscosity for all areas of deforming sediment show a multidomed ice sheet with a large bowl shaped depression over hudson bay and thin ice 1000 m above modern sea level over the western and southern margins those reconstructions that assume a higher effective viscosity of till in the hudson bay region than for the western and southern margins also show a multidomed ice sheet but with considerably thicker ice over hudson bay and a more northerly position of the central ice divide these two different geometries may represent ice sheet orographic changes associated with a heinrich event further increases in effective viscosity of till approaching the effective viscosity of ice would result in a high monolithic ice dome centered over hudson bay reinforcing the notion that a multidomed ice sheet reflects the distribution of substrate geology modeled ice surface geometry at the last glacial maximum shows many of the same general features as previous reconstructions that incorporate deformable beds our reconstructions with higher effective till viscosities in hudson bay also agree with the ice 4g reconstructions peltier 1994 which are based on inversion of relative sea level data for the early part of the last deglaciation 18 13 14c ka but then depart significantly from ice 4g beginning at about 12 14c ka due to differing assumptions of the history of deglaciation modeled ice volume for the last glacial maximum suggests a glacioeustatic change of 50 55 m by a soft bedded laurentide ice sheet this would increase as the effective viscosity of till increases subsequent ice volume changes through the last deglaciation generally parallel the trend of eustatic rise recorded at barbados new guinea and tahiti but suggest that the laurentide ice sheet was not the source of meltwater pulse 1a

climate change record in subsurface temperatures a global perspective analyses of underground temperature measurements from 358 boreholes in eastern north america central europe southern africa and australia indicate that in the 20th century the average surface temperature of earth has increased by about 0 5 degreesc and that the 20th century has been the warmest of the past five centuries the subsurface temperatures also indicate that earth s mean surface temperature has increased by about 1 0 degreesc over the past five centuries the geothermal data offer an independent confirmation of the unusual character of 20th century climate that has emerged from recent multiproxy studies

reconstructing millennial scale regional paleoclimates of boreal canada during the holocene abstract regional paleoclimate reconstructions for northern canada quantify holocene climate variability on orbital and millennial time scales and provide a context to better understand the current global warming the reconstructions are based on available pollen diagrams from the boreal and low arctic zones of canada and use the modern analog technique mat four regional reconstructions document the space time evolution of the climate during the holocene highest summer and winter temperatures anomalies are found in central canada during the early holocene eastern canada was relatively cool in the early holocene whereas central canada was warmest at that time labrador was relatively dry in the early to mid holocene during which time western canada was relatively moist millennial scale temperature variations especially the medieval warm period and little ice age are seen across the continent with some suggestion of time transgressive changes from west to east at the millennial scale precipitatio

sediment yield in europe spatial patterns and scale dependency abstract our understanding about the regional variation of sediment yield sy in europe and its scale dependency currently relies on a limited number of data for mainly larger river systems sy is the integrated result of all erosion and sediment transporting processes operating in a catchment and is therefore of high value for environmental studies and monitoring purposes most global assessments of sy consider catchment area a climate and topography as the main explanatory variables however it is still unclear if these factors also control regional variations of sy within europe this paper aims at bridging this gap therefore we i present a large database of sy values which was constructed through an extensive literature review ii describe the spatial patterns of sy across europe and iii explore its relation with a climate and topography in total sediment yield data from 1794 different locations throughout europe were collected 507 reservoirs and 1287 gauging stations representing a minimum of 29 203 catchment year data only sy data measured at gauging stations or derived from reservoir siltation rates over a period of a minimum of one year were included in the database this database comprises a large range of catchment areas a i e from small upland catchments 0 01 km to major european river basins 1 360 000 km an overview of the collected sy data is provided and sources of uncertainty on the available data are discussed despite potentially large uncertainties on several of the individual sy values analysis of this database indicates clear spatial patterns of sy in europe the temperate and relatively flat regions of western northern and central europe generally have relatively low sy values with ca 50 of the sy 40 t km 2 yr 1 and ca 80 of the data 2 yr 1 while mediterranean and mountainous regions generally have higher sy values with around 85 of the sy data 40 t km 2 yr 1 and more than 50 of the data 200 t km 2 yr 1 these differences are attributed to a combination of factors such as differences in climate topography lithology and land use although larger differences in sy were found between the climatic regions than between topographic zones it is currently difficult to identify the individual importance of the various controlling factors of sy sy a relationships were calculated for the entire dataset and for subgroups stratified according to the measurement method gauging stations or reservoir surveys range of the catchment area climatic region topographic zone of the river outlet and major european river system although typically a negative relationship between sy and a is expected due to a decrease in topsoil erosion rates on more gentle slopes and an increase in sediment deposition with an increase in catchment size this relationship was found to be generally very weak and subject to a lot of scatter furthermore results illustrate important differences in scale dependency whereas a weak but significant negative trend is generally observed for the temperate and relatively flat regions no significant or even positive trends were observed in mountain regions and mediterranean europe when only larger river catchments i e 100 km and especially 10 000 km are considered catchment area exerted a larger control on sy these findings confirm previous studies and indicate that the relationship between sy spatial scale and other controlling factors is often complex and non linear

late quaternary ice sheet history of northern eurasia the maximum limits of the eurasian ice sheets during four glaciations have been reconstructed 1 the late saalian 140 ka 2 the early weichselian 100 80 ka 3 the middle weichselian 60 50 ka and 4 the late weichselian 25 15 ka the reconstructed ice limits are based on satellite data and aerial photographs combined with geological field investigations in russia and siberia and with marine seismic and sediment core data the barents kara ice sheet got progressively smaller during each glaciation whereas the dimensions of the scandinavian ice sheet increased during the last ice age the barents kara ice sheet attained its maximum size as early as 90 80 000 years ago when the ice front reached far onto the continent a regrowth of the ice sheets occurred during the early middle weichselian culminating about 60 50 000 years ago during the late weichselian the barents kara ice sheet did not reach the mainland east of the kanin peninsula with the exception of the nw fringe of taimyr a numerical ice sheet model forced by global sea level and solar changes was run through the full weichselian glacial cycle the modeling results are roughly compatible with the geological record of ice growth but the model underpredicts the glaciations in the eurasian arctic during the early and middle weichselian one reason for this is that the climate in the eurasian arctic was not as dry then as during the late weichselian glacial maximum

post fire hydrological response and suspended sediment transport of a terraced mediterranean catchment in july 2013 a wildfire severely affected the western part of the island of mallorca spain during the first three post fire hydrological years when the window of disturbance tends to be more open the hydrological and sediment delivery processes and dynamics were assessed in a representative catchment intensively shaped by terracing that covered 37 of its surface area a nested approach was applied with two gauging stations covering 1 2 km2 and 4 8 km2 built in september 2013 that took continuous measurements of rainfall water and sediment yield average suspended sediment concentration 1 503 mg l 1 and the maximum peak 33 618 mg l 1 were two orders of magnitude higher than those obtained in non burned terraced catchments of mallorca this factor may be related to changes in soils and the massive incorporation of ash into the suspended sediment flux during the most extreme post fire event 50 mm of rainfall in 15 minutes reaching an erosivity of 2 886 mj mm ha 1 h 1 moreover hysteretic counter clockwise loops were predominant 60 probably related to the increased sensitivity of the landscape after wildfire perturbation though the study period was average in terms of total annual precipitation even higher in intensities minimal runoff 2 and low sediment yield 6 3 t km 2 y 1 illustrated how the intrinsic characteristics of the catchment i e calcareous soils terraces and the application of post fire measures limited the hydrosedimentary response despite the wildfire impact

runoff and erosion processes after a forest fire in mount carmel a mediterranean area in the mediterranean forest area of israel fires increase runoff and sediment yield rates relative to undisturbed forested land the september 1989 fire covered an area of 4 km2 in the main recreation area of mount carmel a typical mediterranean forest area the lithology is chalk and limestone and about 40 of the burnt area has steep slopes exceeding 30 three study plots were established in burnt and unburnt areas plots were located on 100 300 m2 areas with different slope exposures runoff and sediments were collected after each storm by a collector system a hydrometric station was established draining an area of 1 km2 in the burnt zone rainfall was measured by two recorders and several rain gauges at the experimental sites in the first rainfall season after the fire runoff and sediment yield were 500 and 100 000 times higher respectively in the burnt areas rainfall intensity is a dominant factor in runoff and sediment yield rates in the measured basin total runoff in the first year was 1 6 revegetation recovery of the area was rapid as shown by the results from the second season runoff decreased by one order of magnitude from an average of 10 mm to 1 5 mm sediment yield decreased by two orders of magnitude from 1200 g m 2 to 10 g m 2 the third season 1991 1992 was an exceptionally rainy year and therefore runoff and sediment yield increased but to less than in the first year runoff and sediment yield are related to vegetation cover rainfall intensity soil properties slope steepness and exposure and fire intensity logging activities after fire increase sediment yields through its effects on vegetation cover and soil fire severity increases the potential for erosion

the effects of wildfire on the sediment yield of a coastal california watershed the occurrence of two wildfi res separated by 31 yr in the chaparral dominated arroyo seco watershed 293 km 2 of california provides a unique opportunity to evaluate the effects of wildfi re on suspended sediment yield here we compile discharge and suspended sediment sampling data from before and after the fi res and show that the effects of the postfi re responses differed markedly the 1977 marble cone wildfi re was followed by an exceptionally wet winter which resulted in concentrations and fl uxes of both fi ne and coarse suspended sediment that were 35 times greater than average sediment yield during the 1978 water year was 11 000 t km 2 yr we suggest that the combined 1977 1978 fi re and fl ood had a recurrence interval of greater than 1000 yr in contrast the 2008 basin complex wildfi re was followed by a drier than normal year and although suspended sediment fl uxes and concentrations were signifi cantly elevated compared to those expected for unburned conditions the sediment yield during the 2009 water year was less than 1 of the post marble cone wildfi re yield after the fi rst postfi re winters sediment concentrations and yield decreased with time toward prefi re relationships and continued to have signifi cant rainfall dependence we hypothesize that the differences in sediment yield were related to precipitationenhanced hillslope erosion processes such as rilling and mass movements the millennialscale effects of wildfi re on sediment yield were explored further using monte carlo simulations and these analyses suggest that infrequent wildfi res followed by flincrease long term suspended sediment fl markedly thus we suggest that the current approach of estimating sediment yield from sediment rating curves and discharge data without including periodic perturbations from wildfi res may grossly underestimate actual sediment yields

fire storms and erosional events in the idaho batholith in late december 1996 the south fork payette river basin in west central idaho experienced a prolonged storm that culminated on january 1 1997 with intense rain on melting snow that triggered slide failures producing debris flows and sediment charged floods failures occurred in saturated cohesionless grussy colluvium derived from weathered idaho batholith granitic rocks many failures along the south fork payette river originated in ponderosa pine forests burned in the 1989 stand replacing lowman fire an example is the 0 49 km 2 jughead creek basin where a single large colluvial failure produced almost 40 of the total volume eroded from the basin and generated a massive and rapid debris flow failures also occurred in steep unburned and unforested drainages such as hopkins creek in this south facing 0 58 km 2 basin 15 colluvial hollows failed but no single failure produced more than 10 of the total eroded volume sediment transport in hopkins creek occurred by prolonged sediment charged sheetflooding despite vegetation differences sediment yields from the geomorphically similar hopkins creek 42 000 mg km 2 and jughead creek 44 000 mg km 2 basins were quite similar these 1997 erosion events are equivalent to several thousand years of sediment yield at low rates 2 7 30 mg km 2 year 1 measured by short term sediment trapping and gauging in idaho batholith watersheds if similar large events were solely responsible for sediment export recurrence intervals ris of several hundred years would account for higher sediment yields averaged over 10 4 year from idaho batholith watersheds dating of small fire induced sheetflooding events in an early holocene tributary junction fan of jughead creek indicates that frequent small sedimentation events ri 33 80 year occurred between 7400 and 6600 cal year bp with an average yield not greatly exceeding 16 mg km 2 year 1 compared with the holocene average erosion rates during that 800 year period were unusually low suggesting that sediment yields have not been constant over time and that climatic variations and related fire regime changes may exert a strong influence on the probability of major erosional events copyright 2001 john wiley sons ltd

runoff generation sediment movement and soil water behaviour on calcareous limestone slopes of some mediterranean environments in southeast spain abstract an interpretation of soil hydrology and erosion data obtained from limestone areas in southeast spain is presented in the framework of recent hypotheses on runoff generation mechanisms in mediterranean environments the main objective is to synthesise and harmonise the data in theoretical concepts or behavioural models of hydrological functioning of mediterranean limestone slopes for this purpose data were collected in a typical limestone area with climatic characteristics ranging from subhumid to semiarid several sites were chosen with comparable slopes vegetation and soils along a transect of 20 km to carry out several research projects the data discussed in this paper consist of information on water redistribution within the soil profiles obtained from long duration up to 5 h rainfall simulation experiments with continuous monitoring of soil moisture at different depths runoff and sediment concentration data were obtained i from rainfall simulation experiments with different antecedent soil moisture conditions and ii as natural results from open gerlach plots on runoff and sediment movement over 4 years three conceptual models of water redistribution during the infiltration process could be observed two of them imply nonuniform water redistribution within the soil profile due mainly to macropore flow caused by specific soil surface characteristics at the plot scale runoff generated in bare patches is mainly hortonian in plots with previously wetted soils or soils with high infiltration capacities the generated runoff implies the saturation of the upper soil both types of runoff are discontinuous through time and space the runoff generation mechanisms at the slope scale have been synthesised into two conceptual models a hortonian discontinuous runoff model that takes place in the most degraded slopes or during high intensity rain events and a mixed runoff generation model in less degraded slopes or in previously wet soils where infiltration excess runoff as well as saturation excess runoff can happen on the same slope in both cases slopes behave as a patchwork of runoff and runon areas the size of the runoff or runon patches is dependent on the climatological conditions these control the hydrological disconnection between different parts of the slopes hortonian and saturation runoff can both be generated and infiltrated downslope

erosion in mediterranean landscapes changes and future challenges abstract intense erosion processes are widespread in the mediterranean region and include sheet wash erosion rilling gullying shallow landsliding and the development of large and active badlands in both subhumid and semi arid areas this review analyses the main environmental and human features related to soil erosion processes and the main factors that explain the extreme variability of factors influencing soil erosion particularly recent land use changes the importance of erosion in the mediterranean is related to the long history of human activity in a region characterized by low levels of annual precipitation the occurrence of intense rainstorms and long lasting droughts high evapotranspiration the presence of steep slopes and the occurrence of recent tectonic activity together with the recurrent use of fire overgrazing and farming these factors have resulted in a complex landscape in which intensification and abandonment wealth and poverty can co exist the changing conditions of national and international markets and the evolution of population pressure are now the main drivers explaining land use changes including farmland abandonment in mountain areas the expansion of some subsidized crops to marginal lands and the development of new terraces affected by landslides and intense soil erosion during extreme rainstorm events the occurrence of human related forest fires affecting thousands of hectares each year is a significant problem in both the northern and southern areas of the mediterranean basin here we highlight the rise of new scientific challenges in controlling the negative consequences of soil erosion in the mediterranean region 1 to reduce the effects and extent of forest fires and restructure the spatial organization of abandoned landscapes 2 to provide guidance for making the eu agricultural policy more adapted to the complexity and fragility of mediterranean environments 3 to develop field methods and models to improve the identification of runoff and sediment contributing areas 4 to contribute to the conservation of landscapes i e bench terraced fields having high cultural and productivity values 5 to improve knowledge of the hydrological and geomorphological functioning of badlands with the aim of reducing sediment yield and accessibility 6 to better understand the effect of climate change on soil erosion in the mediterranean region and 7 to improve quantitative information on long term soil erosion

routing of meltwater from the laurentide ice sheet during the younger dryas cold episode rooth1 proposed that the younger dryas cold episode which chilled the north atlantic region from 11 000 to 10 000 yr bp was initiated by a diversion of meltwater from the mississippi drainage to the st lawrence drainage system the link between these events is postulated to be a turnoff during the younger dryas cold episode of the north atlantic s conveyor belt circulation system which currently supplies an enormous amount of heat to the atmosphere over the north atlantic region2 this turnoff is attributed to a reduction in surface water salinity and hence also in density of the waters in the region where north atlantic deep water nadw now forms here we present oxygen isotope and accelerator radiocarbon measurements on planktonic foraminifera from orca basin core en32 pc4 which reveal a significant reduction in meltwater flow through the mississippi river to the gulf of mexico from about 11 200 to 10 000 radiocarbon years ago this finding is consistent with the record for lake agassiz which indicates that the meltwater from the southwestern margin of the laurentide ice sheet was diverted to the northern atlantic ocean through the st lawrence valley during the interval from 11 000 to 10 000 years before present yr bp

sediment concentration versus water discharge during single hydrologic events in rivers relations between sediment concentration c and water discharge q for a hydrologic event such as a flood are studied qualitatively by analyzing smoothed temporal graphs discharge and concentration vs time in terms of mode spread and skewness comparing cq ratios at a given discharge on the rising and falling limbs of the discharge hydrograph provides a consistent reliable method for categorizing c q relations five common classes of such relations are single valued straight or curved clockwise loop counterclockwise loop single valued plus a loop and figure eight temporal graph mode and skewness influence the type of relation whereas temporal graph spread affects the details of the particular c q relation its graphical breadth shape orientation and plotted location field examples of the various types of relations are given including varieties that heretofore have received little attention such as the figure eight explanations for each type of c q relation are discussed

deep 3d thermal modelling for the city of berlin germany this study predicts the subsurface temperature distribution of germany s capital berlin for this purpose a data based lithosphere scale 3d structural model is developed incorporating 21 individual geological units this model shows a horizontal grid resolution of 500 500 m and provides the geometric base for two different approaches of 3d thermal simulations 1 calculations of the steady state purely conductive thermal field and 2 simulations of coupled fluid flow and heat transport the results point out fundamentally different structural and thermal configurations for potential geothermal target units the top of the triassic middle buntsandstein strongly varies in depth 159 2 470 m below sea level and predicted temperatures 15 95 c mostly because of the complex geometry of the underlying permian zechstein salt the top of the sub salt sedimentary rotliegend is rather flat 2 890 3 785 m below sea level and reveals temperatures of 85 139 c the predicted 70 c isotherm is located at depths of about 1 500 2 200 m cutting the middle buntsandstein over large parts of berlin the 110 c isotherm at 2 900 3 700 m depth widely crosscuts the sedimentary rotliegend groundwater flow results in subsurface cooling the extent of which is strongly controlled by the geometry and the distribution of the tertiary rupelian clay the cooling effect is strongest where this clay rich aquitard is thinnest or missing thus facilitating deep reaching forced convective flow the differences between the purely conductive and coupled models highlight the need for investigations of the complex interrelation of flow and thermal fields to properly predict temperatures in sedimentary systems

effects of agricultural drainage systems on sediment connectivity in a small mediterranean lowland catchment abstract traditional drainage systems combining man made channels and subsurface tile drains have been used since roman times to control water excess in mediterranean lowland regions favouring adequate soil water regime for agriculture purposes however mechanization of agriculture abandonment or land use changes lead to a progressive deterioration of these drains in the last decades the effects of these structures on hydrological and sediment dynamics have been previously analyzed in a small mediterranean lowland catchment can revull mallorca spain 1 4 km2 by establishing an integrated sediment budget with a multi technique approach moreover the recent advances in morphometric techniques enable the completion of this analysis by the accurate identification of active areas i e sources pathway links and sinks and improve the understanding of de coupling mechanisms of water and sediment linkages in this study the borselli s index of connectivity ic cavalli et al 2013 s version derived from a lidar based high resolution dem 1 pt m 2 rmse

heat flow variations in a deep borehole near sept iles quebec canada paleoclimatic interpretation and implications for regional heat flow estimates a deep 2000m borehole in the sept iles intrusion on the north shore of the saint lawrence river in quebec canada was repeatedly logged for temperature systematic variations of the temperature gradient with depth are not correlated with the thermal conductivity we interpreted the temperature profile as follows 1 during the last glacial maximum the temperature at the base of the ice sheet was cold 5 c 2 when the region was below sea level between 10 and 5ky b p the ground surface temperature was warm 6 c 3 the average ground surface temperature dropped to 2 c at 5ky b p when the region rebounded above sea level 4 the long time averaged ground surface temperature before the last glacial maximum was 0 1 c 5 the reference heat flow 36 37mw m 2 is 4 5mw m 2 higher than estimated from the upper 1000m of the heat flow profile this interpretation can not be extrapolated to the entire region covered by the laurentide ice sheet except for extremely deep 1500m boreholes the small uncertainty 15 affecting heat flow estimates can not be eliminated

catchment controls and human disturbances on the geomorphology of small mediterranean estuarine systems abstract geographic signatures are physical and human induced characteristics or processes that identify comparable or unique features of estuaries along latitudinal gradients in mediterranean areas the microtidal regime and the strong seasonal and inter annual contrasts cause an alternation between relatively high runoff and arid conditions furthermore the long history of human settlement also increases the complexity in the study of these estuarine systems this study investigates these signatures of the estuaries located within the mallorcan eastern coast which are geomorphologically homogeneous because of a similar bedrock geology and holocene history a multi method approach focused on the integration of geomorphometry hydraulics historical sources and statistics was used we explore the role played by catchment morphometric parameters severe flash flood events and human disturbances in controlling the geomorphology of 10 beach barrier enclosed fluvial incised lagoons most of the lagoons discharge into calas ranging in size from 1345 to 17 537 m 2 and their related catchments are representative of the mediterranean hydrological systems multiple regression models illustrate that the size slope and drainage network development of the catchments explain the variance in length r 2 0 67 volume r 2 0 49 area r 2 0 64 circularity r 2 0 72 and average width r 2 0 81 of the lagoons depending on these catchment morphometric variables the shape of the lagoons is also determined by the occurrence of catastrophic flash floods which cause scouring and dredging whereas the ordinary flood events and sea storms promote refilling and sedimentation a historical analysis since 1850 documented 18 flood events 5 of which were catastrophic with destructive effects along the catchments and large morphological changes in coastal lagoons high intensity rainfall up to 200 mm in 2 h the geomorphometry of the catchments and the massive construction of terraces and transverse walls are involved in the generation of catastrophic flood events additionally the lagoons were altered considerably by human intervention for flood control and to allow for an increased amount of human activities within the surrounding areas although the high recurrence of catastrophic flood events causes a persistent difficulty in the human battle to dominate these ecosystems therefore the area occupied by lagoons increased between 1956 and the present time from 31 981 m 2 to 63 802 m 2 because of the high recurrence of catastrophic flood events furthermore tourism demand and a social conservation consciousness have promoted restoration and preservation since the 1990s this study has improved the geomorphological knowledge of small mediterranean estuaries affected by human disturbances in the high energy environment found in mallorca

deep dissolved iron profiles in the eastern north atlantic in relation to water masses concentrations of dissolved iron dfe 0 2 m were determined at two stations in the biscay abyssal plain north east atlantic in march 2002 dfe concentrations in the surface layer 0 23 0 34 nm were typical of winter conditions in this area at 1000 m dfe concentrations increased to 0 62 0 86 nm this feature is consistent with the production of dfe by remineralization of the biogenic material however at this depth mediterranean outflow water mow could be an additional source of dfe below 2500 m dfe concentrations were constant 0 75 0 04 nm an interesting feature of the profiles was the intermediate maximum of dfe 1 19 1 12 nm around 2000 m associated with the labrador sea water lsw we suggest that the iron enrichment of lsw occurred when this water mass reached the continental margin likely in the vicinity of the goban plateau vertical distributions were highly dependent on water masses encountered

ground surface temperature history in southern canada temperatures at the base of the laurentide ice sheet and during the holocene abstract we use temperature profiles from 7 deep 2000 m boreholes located in southern canada to infer ground surface temperature histories gsth during the last glacial maximum lgm and the holocene visual inspection of the heat flow and of the reduced temperature depth profiles reveals significant regional differences with some sites showing conspicuous signs of post glacial warming and other indicating only very small changes in ground surface temperature these differences are confirmed by the inversions of the temperature profiles the most prominent variations in gst are found at the sudbury ontario sites where the present ground surface temperature is high with the exception of sept iles quebec the other sites only show moderate or no variation in gst for all the sites except possibly sept iles temperatures at the base of the ice sheet during the lgm were at or slightly below the melting point of ice temperatures might have been lower a few degrees below 0 c at sept iles these results are consistent with field observations and model predictions suggesting high velocity basal flows in the ice sheet above the studied regions these new data on basal temperatures will provide better quantitative constraints on glacier flow dynamics the inversions give a chronology for the retreat of the ice sheet comparable to other proxies inversion and direct modeling show that following the ice retreat there was a warm period between 2 and 5 ka with temperatures 1 2 k higher than present the inversion yields a time for this episode 1 2 kyr more recent than that inferred by other proxies for the holocene climate optimum hco

numerical simulation of permafrost evolution as a part of sedimentary basin modeling permafrost in the pliocene holocene climate history of the urengoy field in the west siberian basin present day temperature profile may be used as an important constraint for reconstruction of the thermal regime in sedimentary basin modeling this type of profile is significantly non steady state especially for basins located at high and middle latitudes however estimations of past thermal regimes are indefinite and often limited by knowledge of past glaciations and by the simple two layer model usually employed in this paper permafrost modeling was carried out as a continuation of basin modeling of the sedimentary section of urengoy field of the west siberian basin 66 n 77 e consideration of surface temperatures beginning with the triassic a refined initial temperature distribution permafrost modeling for the past 3 4 ma and use of a real lithological cross section distinguish this approach from previous studies depth and time variations in thermophysical parameters of rocks heat conductivity heat capacity unfrozen water content salt content and porosity had a considerable influence

anti clockwise hysteresis in suspended sediment concentration during individual storms holbeck catchment yorkshire england abstract analysis of the flow sediment hysteresis shape may assist in determining the sediment source area in a small basin a clockwise hysteresis occurs when sediment is derived from the bed and banks of the channel or areas adjacent to the channel whereas an anti clockwise hysteresis occurs when the upper part of the slopes is the sediment source area

a generalized framework for modeling the hydrologic and biogeochemical response of a mediterranean temporary river basin summary a generalized framework for the integrated observational and modeling study of a typical greek temporary river is presented a karstic spring flow model was developed for the estimation of daily spring flows into the watershed from its extended karst area the karstic model assumes the existence of an upper faster and a lower slower reservoir that represent the two different karstic formations of the region the karstic spring flow model was coupled with a watershed model the hydrological simulation program fortran hspf in order to simulate the hydrology sediment transport and nutrient loads of krathis river basin forty two percent of krathis river flow was estimated to be from the contribution of the karstic springs the combined models simulated the time response of the watershed based on geochemical and hydrologic mass balances the seasonal variability of flow and the concentrations of suspended solids and nutrients was captured by the simulations the karstic model was shown to be a useful tool for analyzing karstic systems by estimating the contributing area of the karst and its response to precipitation events this framework can be used to simulate watersheds where karstic geologic formations predominate

muted responses of streamflow and suspended sediment flux in a wildfire affected watershed abstract in august 2003 a severe wildfire burnt 62 of fishtrap creek a 158 km 2 watershed in central british columbia canada streamflows were obtained for the period 1980 2010 and suspended sediment fluxes were determined for the period 2004 2010 for fishtrap creek and these were compared to data for nearby jamieson creek which was not affected by the wildfire peak streamflows in fishtrap creek after the wildfire were not significantly higher than before the wildfire although total annual runoff had increased perhaps the most important change in streamflows following the wildfire was that peak flows associated with the annual freshet occurred earlier in the year by ca 2 weeks following the wildfire monthly total suspended sediment fluxes peaked in april in fishtrap creek and may in jamieson creek which reflects the change in timing of peak streamflows in fishtrap specific suspended sediment yields were low in the first year following the wildfire 2004 and peak values for the 2004 2010 monitoring period occurred in 2006 average specific suspended sediment yields over the monitoring period were similar for both watersheds at 2 8 and 2 9 t km 2 year 1 for fishtrap and jamieson watersheds respectively the muted responses of streamflows and suspended sediment fluxes following this severe wildfire are due to the lack of winter precipitation and the low intensities of summer rainfall events in the first year following the wildfire greater winter precipitation and associated snowmelt in subsequent years coincided with vegetation recovery the major changes in the wildfire affected watershed were increased bank erosion and channel migration due to a loss of root strength and cohesion which occurred 3 5 years after the fire this work demonstrates that the hydrological and geomorphological responses of watersheds to wildfires are a function of the severity of the wildfire and the timing and nature of driving forces i e rainfall intensity winter precipitation and snowmelt during the progression of vegetation recovery

temporal distribution of suspended sediment transport in a humid mediterranean badland area the araguas catchment central pyrenees abstract this paper analyses the temporal patterns of suspended sediment yield in the araguas catchment central spanish pyrenees a small experimental catchment with extensive badlands the catchment has been monitored since 2004 to study weathering erosion and hydrological and sediment responses to understand the superficial dynamics of a badland area in a relatively humid environment the development of badlands in the central spanish pyrenees is favoured by the presence of marls and a markedly seasonal climate the continuous observation of selected physical parameters and environmental variables enables us to establish seasonal patterns of weathering processes and identify those factors that control regolith development freeze thaw cycles in winter and wetting drying in spring summer are the main processes involved in regolith weathering thereby controlling slope development in combination with rainfall related erosion processes the 64 floods recorded during the study period december 2005 to january 2007 were used for a hydrosedimentological analysis the main observed features indicate that the araguas catchment reacts to all rainfall events resulting in steep rising and recession limbs on the hydrograph and a very short time lag floods show high suspended sediment concentrations and a heterogeneous temporal distribution related to seasonal variations in surface runoff production these differences increase the degree of complexity involved in studying sediment response suspended sediment concentration and transport mainly depend on rainfall volume maximum rainfall intensity peak flow and runoff occurrence finally the similarities among the obtained hydrographs sedigraphs and hyetographs in combination with the rapid response of most of the floods suggest a large contribution of overland flow derived mainly from infiltration excess runoff upon badland areas accordingly the significant correlations obtained between rainfall intensity and sediment concentration mainly during the dry season which suggest a single source area for both runoff and sediment also support the hypothesis of hortonian hydrological response within badland areas

surface heat flux histories from inversion of geothermal data energy balance at the earth s surface past changes in the earth s surface energy balance propagate into the subsurface and appear as perturbations of the subsurface thermal regime this paper presents a singular value decomposition inversion method used to reconstruct surface heat flux histories shfh from the heat flux anomalies detected in the shallow subsurface synthetic tests were used to assess the robustness of the inversion procedure it was found that data noise can have a significant effect on the stability of the shfh inferred from inversion this translates in shfhs having lower temporal resolution than ground surface temperature histories gsths obtained from the same data but the long term trends are robust results are encouraging for temperature data noise levels typically encountered in field measurements synthetic data tests yield results in agreement with analytical expressions derived from gsths for the same parameterization temperature depth profiles from canada s geothermal database were used to illustrate the inversion procedure individual temperature profile inversions are shown as examples all 112 temperature logs in the database were used to obtain a mean heat flux history for the region results indicate that the ground heat flux has increased an average of 24 mw m 2 over the last 200 years in canada application of this method to the existing global geothermal data base should allow for a quantification of the global energy balance at the earth s surface for the past few centuries and may be useful for land surface models

new terrestrial heat flow map of europe after regional paleoclimatic correction application heat flow variations with depth in europe can be explained by a model of surface temperature changes 10 c new heat flow map of europe is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continent correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing of which glacial interglacial history has the largest impact it is obvious that large part of the uncorrected heat flow values in the existing heat flow databases from wells as shallow as few hundreds of meters is underestimated this explains some very low uncorrected heat flow values 20 30 mw m2 in the shields and shallow basin areas of the craton also heat flow values in other areas including orogenic belts are likely underestimated based on the uncorrected and corrected heat flow maps using 5 km 5 km grid we have calculated average heat flow values uncorrected heat flow 56 0 mw m2 sd 20 3 mw m2 vs corrected heat flow 63 2 mw m2 sd 19 6 m wm2 and heat loss for the continental part total heat loss is 928 e09 w for the uncorrected values versus corrected 1050 e09 w

climate change on the colorado plateau of eastern utah inferred from borehole temperatures temperature profiles from boreholes on the colorado plateau of southeastern utah have been examined for evidence of climate change because these boreholes penetrate layered sedimentary rocks with different thermal conductivities bullard plots temperature versus integrated thermal resistance are used to estimate background heat flow and surface temperature intercepts reduced temperatures which represent departures from a constant heat flow condition are inverted for a surface ground temperature history at each borehole site using a singular value decomposition algorithm singular value cutoffs are selected by analyzing the spectral energy and the standard deviation of the model fit to the data as a function of the number of eigenvalues solutions are constructed from areas of large spectral energy and a cutoff where additional eigenvalues fail to improve the solution significantly the solution is parameterized in terms of 13 time steps increasing in duration and going back 400 years eight of nine borehole sites indicate between 0 4 and 0 8 c 0 2 c warming over the past 200 years with some evidence for accelerated warming in this century one borehole indicates local cooling over the same time period the amplitude of the warming inferred from borehole temperatures is less than that deduced from analysis of 100 year surface air temperature records at four of the five weather stations surrounding the borehole sites

the climate record inverted from borehole temperatures in slovenia abstract temperature profiles from nine boreholes in slovenia located mostly in the northeastern part of the country have been studied for evidence of past climatic changes the reconstruction of the ground surface temperature gst history based on 1 d theory of heat conduction was accomplished using the functional space inversion fsi method because of the paucity of quality thermal conductivity data and because the nature of heat conduction is such that information about gst changes decay with the passage of time the a priori standard deviations of the thermal conductivity model 1 w m 1 k 1 and measured temperature 0 2 k were chosen large enough so that the gst histories older than 200 years are considerably smoothed and essentially merge with the long term mean the average gst history based on consistent results from seven boreholes starts to rise at the end of the last century the amplitude of the warming is about 0 6 to 0 7 k in the past 100 years two boreholes were rejected the long term mean gsts lie between 9 4 and 11 1 c the mean annual air temperatures from the ljubljana meteorological station are in good agreement with the average gst solution the gst history of the past 20 30 thousand years ka was reconstructed from the almost 2 km deep ljutomer temperature profile the history evidences climate variations during the wurm weichselian ice age it places the glacial minimum of about 3 c at 13 14 ka ago and the postglacial maximum of 10 5 c roughly at 2 3 ka ago

chronological and behavioral contexts of the earliest middle stone age in the gademotta formation main ethiopian rift there is a general consensus that our species emerged first in africa currently the best known skeletal evidence for the earliest anatomically modern homo sapiens amhs derives from sites in the rift valley in ethiopia however archaeological evidence from cave sites in southern and northern africa largely dominates discussions on behaviors that characterize the dawn of modern humans later middle pleistocene open air sites in east africa present unparalleled geochronological control and thus a better chance to study hominin behavior here we present results of a multidisciplinary investigation of the archaeology and geochronology of one of the oldest known middle stone age msa occupations from the gademotta formation fm in the main ethiopian rift renewed excavation lithic analysis fracture mechanics and tephrochronological investigations at gademotta provide a better understanding of the chronological and behavioral contexts during the critical period immediately preceding the origin of our species

dynamics of the north american ice sheet complex during its inception and build up to the last glacial maximum the north american ice sheet complex played a major role in global sea level fluctuations during the late quaternary but our knowledge of its dynamics is based mostly on its demise from the last glacial maximum lgm a period characterised by non linear behaviour in the form of punctuated ice margin recession episodic ice streaming and major shifts in the location of ice divides in comparison knowledge of the pre lgm ice complex is poorly constrained largely because of the fragmentary nature of the evidence relating to ice sheet build up in this paper we explore the inception and growth of ice 120 20 ka using a glacial systems model which has been calibrated against a large and diverse set of data relating to the deglacial interval we make use of calibration data prior to the lgm but its scarcity introduces greater uncertainty which is partly alleviated by our large ensemble analysis results suggest that following the last interglaciation oxygen isotope stage ois 5e the ice complex initiated over the north eastern canadian arctic and in the cordillera within a few thousand years it then underwent rapid growth to an ois 5 maximum at 110 ka 5d and covered 70 of the area occupied by the lgm ice cover although only 30 by volume an ois 5 minimum is modelled at 80 ka 5a before a second phase of rapid growth at the start of ois 4 which culminated in a large ice complex at 65 ka almost as large as at the lgm subsequent deglaciation was rapid maximum modelled sea level contribution of 16 cm per century and resulted in an ois 3 minimum between ca 55 60 ka thereafter the ice complex grew towards its lgm configuration interrupted by several phases of successively less significant mass loss our results support and extend previous inferences based on geological evidence and reinforce the notion of a highly dynamic pre lgm ice complex e g with episodes of 10 s m of eustatic sea level equivalent in 50 but even the thin ois 5 ice sheets exhibit fast flow features several 1000 m a 1 in major topographic troughs notwithstanding the severe limitations imposed by the use of the shallow ice approximation we note that most fast flow features generated prior to the lgm correspond to the location of known ice streams during deglaciation i e in major topographic troughs and over soft sediments at the southern and western margins moreover the modelled flux of these ice streams sensu lato appears to be non linearly scaled to ice sheet volume i e there is no evidence that decay phases were associated with significantly increased ice stream activity this hypothesis requires testing using a model with higher order physics and future modelling would also benefit from additional pre lgm constraints e g dated ice free margin positions to help reduce and quantify uncertainties

deglaciation ages and meltwater routing in the fort mcmurray region northeastern alberta and northwestern saskatchewan canada a field based reconstruction of the deglacial paleogeography in the fort mcmurray area permits 1 constraining the timing of meltwater routing to the arctic from the present hudson bay drainage basin and 2 minimum age estimates for ice margin positions that can be used to constrain ice sheet modeling results a downslope recession of the laurentide ice sheet resulted in a series of proglacial lakes forming between the ice margin and higher land to the southwest the paleogeography of these lakes is poorly constrained in part from the masking effect of boreal forest vegetation and map scale issues however recent space shuttle based dems increase the number and spatial extent of moraines identified within the study area resulting in a coherent pattern of ice margin retreat focused on the athabasca river valley an intensive lake coring program resulted in a minimum ten fold increase in the radiocarbon database used to limit moraine ages results indicate that deglaciation in this region was younger than previously reported and it is likely that the meltwater could not drain northward to the arctic ocean from any source southeast of the fort mcmurray area until approximately 9850 9660 14 cbp

interpretation and mathematical modeling of temporal changes of temperature observed in borehole yaxcopoil 1 within the chicxulub impact structure mexico summary geothermal research of the chicxulub impact structure on the yucatan peninsula mexico included repeated temperature logs following 0 3 0 8 15 24 34 and 50 months after shut in of drilling operations at the 1 5 km deep yaxcopoil 1 borehole a gradual distortion of the linear temperature profile by a cold wave propagating downward from 145 m to 317 m was detected within the observational period of 49 months march 2002 april 2006 the amplitude of the cold wave was increasing with depth and time in the range of 0 8 1 6 c as an explanation of this unusual phenomenon the hypothesis of downward migration of a large volume of drilling mud reported lost during drilling within the overlying and cooler highly porous and permeable karstic rocks has been proposed the thermal effects of the migrating fluid have been evaluated by solving numerically the heat conduction convection equation in appropriate geothermal models the best coincidence between the observed data and the simulations was yielded by the model of the drilling mud migrating as a large body parameters of this model are constrained by the measured temperature logs relatively tightly i the vertical extent of the downward migrating fluid body is about 5 10 m possibly increasing within the observational period of 49 months by a factor of 2 ii the horizontal extent of the body must be at least 15 20 m i e by order s of magnitude larger than the diameter of the borehole iii the average speed of the migration is about 5 metres per month and iv the fluid must migrate through a highly porous rock 80 porosity or more this high porosity which is necessary for the model to fit the observed data and the observed relatively stable velocity of the migration indicate the existence of a well developed system of interconnected cavities down to more than 300 m about 150 m more than the deepest cave system known in yucatan yet

holocene thermal maximum in the western arctic 0 180 w the spatio temporal pattern of peak holocene warmth holocene thermal maximum htm is traced over 140 sites across the western hemisphere of the arctic 0 180 w north of 60 n paleoclimate inferences based on a wide variety of proxy indicators provide clear evidence for warmer than present conditions at 120 of these sites at the 16 terrestrial sites where quantitative estimates have been obtained local htm temperatures primarily summer estimates were on average 1 6 0 8 c higher than present approximate average of the 20th century but the warming was time transgressive across the western arctic as the precession driven summer insolation anomaly peaked 12 10 ka thousands of calendar years ago warming was concentrated in northwest north america while cool conditions lingered in the northeast alaska and northwest canada experienced the htm between ca 11 and 9 ka about 4000 yr prior to the htm in northeast canada the delayed warming in quebec and labrador was linked to the residual laurentide ice sheet which chilled the region through its impact on surface energy balance and ocean circulation the lingering ice also attests to the inherent asymmetry of atmospheric and oceanic circulation that predisposes the region to glaciation and modulates the pattern of climatic change the spatial asymmetry of warming during the htm resembles the pattern of warming observed in the arctic over the last several decades although the two warmings are described at different temporal scales and the htm was additionally affected by the residual laurentide ice the similarities suggest there might be a preferred mode of variability in the atmospheric circulation that generates a recurrent pattern of warming under positive radiative forcing unlike the htm however future warming will not be counterbalanced by the cooling effect of a residual north american ice sheet

discriminating fine sediment sources and the application of sediment tracers in burned catchments a review wildfire can cause substantial changes to runoff erosion and downstream sediment delivery processes in response to these disturbance effects the main sources of sediment transported within burned catchments may also change sediment tracing offers an approach to determine the proportional contributions of fine sediment typically 63 m from burned catchment sources in this paper we review the application of various sediment tracers to discriminate fine sediment sources following wildfire fallout radionuclides provide the most effective tracers for discriminating hillslope surface and sub surface usually channel bank sources previous tracer studies quantifying contributions from these sources after wildfire are based exclusively on radionuclides the potential for fallout radionuclides to discriminate spatial sources defined according to burned and unburned areas depends on burn related changes in surface soil concentrations tracing of burned and unburned source areas will be problematic where most radionuclides in surface material are bound to ash rather than soil geochemical properties of surface soils are probably too susceptible to natural and burn related variability to consistently discriminate burn defined spatial sources mineral magnetic properties have shown potential for discriminating soil burned at different severities as well as unburned areas more research is needed to assess the use of soil organic compounds as tracers of burned source areas linking fallout radionuclide based hillslope and channel source discrimination with process measurements and monitoring after fire can provide enhanced insight into fine sediment transfer and related water quality impacts adopting such integrated and multi scale approaches would contribute to improved understanding of hydrological and geomorphological responses to wildfire copyright 2012 john wiley sons ltd

thermal simulation of subsea saline permafrost thermal analyses of the response of offshore permafrost to emergence and submergence have traditionally employed simple closed form solutions where phase change is confined to a discrete freezing temperature these have led to rather rapid rates of return to thermal equilibrium which have proved difficult to explain in the light of recent deep temperature measurements in offshore permafrost profiles this paper reviews the need for an appropriate unfrozen water content relationship for a saline frozen soil and describes some simulations of long term thermal response in offshore permafrost using the author s geothermal simulator simulations of submergence assumed an initial permafrost thickness of 600 m and a mean soil surface temperature of 9 0 c the salinity was assumed constant at 30 the initial temperature profile was linear varying between 9 0 c and a freezing point of 1 8 c at the bottom of ice bonded permafrost the temperature of the ground surface was assumed to have changed to 0 8

fallout radionuclide tracers identify a switch in sediment sources and transport limited sediment yield following wildfire in a eucalypt forest abstract fire can alter sediment sources and transport rates in river basins changing landforms and aquatic habitats and degrading downstream water quality variability in the response between environments between fires and with time since fire makes predicting the catchment scale effect of individual fires difficult this study applies the fallout radionuclides 137cs and 210pbxs to trace the sources and transport of fine sediment through a river network following a wildfire of moderate to extreme severity in the 629 km2 eucalypt forested nattai river water supply catchment near sydney australia the tracer analysis showed that post fire erosion caused a switch in fine

temperature and heat flux changes at the base of laurentide ice sheet inferred from geothermal data evidence from province of alberta canada using a previously published temperature log of the 2363 m deep borehole hunt well alberta canada and the results of its previous interpretation the new reconstructions of ground surface temperature and surface heat flux histories for the last 30 ka have been obtained two ways to adjust the timescale of geothermal reconstructions are discussed namely the traditional method based on the a priori data on thermal diffusivity value and the alternative one including the orbital tuning of the surface heat flux and the earth s insolation changes it is shown that the second approach provides better agreement between geothermal reconstructions and proxy evidences of deglaciation chronology in the studied region

measuring use related fracture velocity in lithic armatures to identify spears javelins darts and arrows this study employs a brittle fracture mechanics based approach to explore the relationship between lithic fracture velocity and precursory loading rate in fine grained lithic armatures the data demonstrate that only high speed dart and arrow armatures are subject to dynamic loading events whereas spear and javelin armatures are limited to rapid and quasi static loading the data presented were derived from controlled experiments employing spears javelins spearthrower darts and arrows armatures associated with both bow and spearthrower technologies are reliably identified and distinguished from those of low speed technologies such as spears and javelins javelin armatures may also sustain higher velocity fractures than spear armatures thus permitting the further differentiation of these technologies the methodology offers a quantitative non subjective means to identify the delivery technology associated with a lithic armature

finding the paleoindian spearthrower quantitative evidence for mechanically assisted propulsion of lithic armatures during the north american paleoindian period abstract archaeologists have long assumed that fluted points were used by north american paleoindians as spearthrower dart armatures despite a lack of empirical evidence of the spearthrower from the paleoindian period employing non subjective quantitative data derived from velocity dependent micro fracture features observed on damaged fluted and un fluted paleoindian lithic points this research presents empirical evidence for the existence of the paleoindian spearthrower in addition the research serves as proof of concept for a novel quantitative method of lithic analysis that has far reaching potential to contribute significantly to our understanding of the human past

varves and mass movement deposits record distinctly different sedimentation dynamics since the late glacial lake szurpily northeastern poland the sedimentological and geochemical characteristics of sediments from lake szurpily northeastern poland can be used as a record of mass movement and climate dynamics since the allerod late glacial sediments suggest enhanced runoff conditions in the catchment after the retreat of the scandinavian ice sheet while holocene varved sediments are interrupted by mass movement deposits mmds we identified 85 thin 1 m thick mmd type 2 consists of auto and allochthonous material and represents multistage processes including erosion and deformation of underlying varved sediments rapid deposition of clastic material and redeposition of previously eroded varved sediments seismic activity or permafrost degradation was responsible for the deposition of mmd type 2 furthermore varve thickness variability suggests gleissberg and suess solar cycles before 850 bc when human impact was limited additionally 22 and 11 yr sunspot cycles are recognized in light dark laminae thickness ratios and reflect influences of solar irradiance on lacustrine productivity

the fennoscandian ice sheet during the late weichselian geothermal evidence geothermal estimates of the ground surface temperatures for the last glacial cycle in northern europe have been analysed during the middle and late weichselian 55 12 kyr bp a substantial part of this area was covered by the fennoscandian ice sheet the analysis of geothermal data allows reconstructing the limits of ice sheet extent and its basal thermal state in the late weichselian ground surface temperatures outside the ice sheet were extremely low from 7 to 17 c within the ice sheet there were both thawed and frozen zones the revealed temperature pattern is generally consistent with the modern one for ground surface temperatures in greenland which makes it possible to consider these ice sheets as analogues the anomalous climatically induced surface heat flux and orbital insolation of the earth varied consistently outside the glaciation and independently within the limits of the ice sheet

groundwater control on the suspended sediment load in the na borges river mallorca spain abstract groundwater dominance has important effects on the hydrological and geomorphological characteristics of river systems low suspended sediment concentrations and high water clarity are expected because significant inputs of sediment free spring water dilute the suspended sediment generated by storms however in many mediterranean rivers groundwater dominance is characterised by seasonal alternations of influent and effluent discharge involving significant variability on the sediment transport regimes such areas are often subject to soil and water conservation practices over the centuries that have reduced the sediment contribution from agricultural fields and favour subsurface flow to rivers moreover urbanisation during the twentieth century has changed the catchment hydrology and altered basic river processes due to its flashy regime in this context we monitored suspended sediment fluxes during a two year period in the na borges river a lowland agricultural catchment 319 km 2 on the island of mallorca balearic islands the suspended sediment concentration ssc was lower when the base flow index i e relative proportion of baseflow compared to stormflow bfi was higher therefore strong seasonal contrasts explain the high ssc coefficient of variation which is clearly related to dilution effects associated with different groundwater and surface water seasonal interactions a lack of correlation in the q ssc rating curves shows that factors other than discharge control sediment transport as a result at the event scale multiple regressions illustrate that groundwater and surface water interactions are involved in the sedimentary response of flood events in the winter the stability of baseflow driven by groundwater contributions and agricultural and urban spills causes hydraulic variables i e maximum discharge to exert the most important control on events whereas in the summer it is necessary to accumulate important volumes of rainfall creating a minimum of wet conditions in the catchment to activate hydrological pathways and deliver sediment to the drainage network the bfi is also related to sediment delivery processes as the loads are higher with lower bfi corroborating the fact that most sediment movement is caused by stormflow and its related factors overall suspended sediment yields were very low i e 2 yr 1 at all measuring sites such values are the consequence of the limited sediment delivery attributable to soil conservation practices low surface runoff coefficients and specific geomorphic features of groundwater dominated rivers such as low drainage density low gradient steep valley walls and flat valley floors

heat flow variation with depth in poland evidence from equilibrium temperature logs in 2 9 km deep well torun 1 high precision temperature measurements were carried out up to a depth of 2 930 m in the 5 5 km deep well torun 1 26 years after completion of drilling the temperature log provides equilibrium thermal state information for the polish lowland at the western margin of the precambrian craton geothermal gradient calculated from the equilibrium temperature log together with estimates of thermal conductivity from net rock geophysical well logging analysis and available core measurements yields heat flow in the range 50 60 mw m2 below 2 km depth heat flow of 50 mw m2 plus 10 mw m2 generated within thick sediments and highly metamorphosed sedimentary wedge is typical for the western margin of the precambrian east european craton heat flow variations with depth can be explained by a model of surface temperature changes 10 c glaciation to holocene

global glacial isostasy and the surface of the ice age earth the ice 5g vm2 model and grace abstract the 100 kyr quasiperiodic variation of continental ice cover which has been a persistent feature of climate system evolution throughout the most recent 900 kyr of earth history has occurred as a consequence of changes in the seasonal insolation regime forced by the influence of gravitational n body effects in the solar system on the geometry of earth s orbit around the sun the impacts of the changing surface ice load upon both earth s shape and gravitational field as well as upon sea level history have come to be measurable using a variety of geological and geophysical techniques these observations are invertible to obtain useful information on both the internal viscoelastic structure of the solid earth and on the detailed spatiotemporal characteristics of glaciation history this review focuses upon the most recent advances that have been achieved in each of these areas advances that have proven to be central to the construction of the refined model of the global process of glacial isos

short and long term studies of sediment dynamics in a small humid mountain mediterranean basin with badlands abstract badland landscapes are the main sediment sources in the vallcebre area eastern pyrenees catalonia spain short term studies up to 3 years long carried out between 1980 and 1994 were used to estimate the rates of both denudation on bare surfaces and sediment production at the plot scale to analyse the seasonal dynamics of bedrock weathering and regolith behaviour and to study the relationships between geomorphic activity and herbaceous plant colonisation since 1990 stream flow and suspended sediment loads have been monitored using three gauging stations equipped with infrared backscattering turbidimeters ultra sonic beam attenuation solids sensors and automatic water samplers the combination of the two different approaches has been useful for a better perception of the dynamics of the badland systems and to assess the long term contribution of these areas to the basin sediment loads badland erosion at the event scale for a period of 15 years was simulated with the kineros2 model and allowed the long term comparison between badland erosion and sediment yield at the small basin scale badlands are the main source of sediment in the basin for most of the events but infrequent runoff events cause the removal of sediment stores and the activation of other sediment sources the analysis of the uncertainty of sediment yield measurements for a range of record durations demonstrated that long records are needed for obtaining acceptable results due to the high interannual variability relatively low cost short term geomorphic observations may provide information useful for assessing the long term sediment production in these basins with badland areas only if the observations are used to implement a model able to simulate long term observations

effect of postglacial warming seen in high precision temperature log deep into the granites in ne alberta the method how to reconstruct surface temperature history from inversions of precise temperature logs done in wells was pioneered earlier by cermak 1971 and by lachenbruch and marshall 1986 see bodri and cermak 2007 for review and list of references on the subject the method is based on the inversion of stabilized high precision deep borehole temperature logs which are in thermal equilibrium with surrounding rock deep down to some 2 km depth perturbation of the heat flow could be caused by warming since recent glaciations ending some 12 13 kyr ago in canada ritchie 1983 surface temperatures peaked in the holocene optimum 6 7 kyr ago known to be some 1 2 c warmer than recent centuries temperature level kerwin et al 1999 perturbations observed down to 0 1 0 3 km are mainly related to the climate changes of the last 1 2 centuries pollack et al 1998 bodri and cermak 2007 rath et al 2012 on large regional and continental scale all these surface temperature changes influence the subsurface heat flow the method has been applied to reconstruct timing and amplitude of surface temperature change from latest glacial to postglacial climatic history through many areas in eurasia and north america hotchkiss and ingersoll 1934 cermak 1971 kukkonen 1993 kukkonen and safanda 1996 kukkonen et al 1998 mareschal et al 1999 rolandon et al 2003 kukkonen and joeleht 2003 demezhko et al 2007 demezhko and golovanova 2007 majorowicz

quantification of fracture propagation velocity employing a sample of clovis channel flakes velocity dependant lithic fracture surface features are employed to determine precursory loading rate the methodology is applied to a sample of clovis channel flake scars revealing that some clovis points were fluted using pressure flaking techniques

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr