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

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

atmosphere driven ice sheet mass loss paced by topography insights from modelling the south western scandinavian ice sheet abstract marine terminating glaciers and ice streams are important controls of ice sheet mass balance however understanding of their long term response to external forcing is limited by relatively short observational records of present day glaciers and sparse geologic evidence for paleo glaciers here we use a high resolution ice sheet model with an accurate representation of grounding line dynamics to study the deglaciation of the marine based south western norwegian sector of the scandinavian ice sheet and its sensitivity to ocean and atmosphere forcing we find that the regional response to a uniform climate change is highly dependent on the local bedrock topography consistent with ice sheet reconstructions our simulations suggest that ocean warming is able to trigger initial retreat in several fjords but is not sufficient to explain retreat everywhere widespread retreat requires additional ice thinning driven by surface melt once retreat is triggered the underlying bedrock topography and fjord width control the rate and extent of retreat while multi millennial changes over the course of deglaciation are modulated by surface melt we suggest that fjord geometry ice ocean interactions and grounding line dynamics are vital controls of decadal to centennial scale ice sheet mass loss however we postulate that atmospheric changes are the most important drivers of widespread ice sheet demise and will likely trump oceanic influence on future ice sheet mass loss and resulting sea level rise over centennial and longer time scales

a 10be production rate calibration for the arctic we present a baffin bay 10 be production rate calibration derived from glacial deposits in western greenland and baffin island and test our results against published 10 be calibration datasets to develop an arctic 10 be production rate our calibration comprises i 10 be measurements from moraine boulders linked to a 14 c dated moraine at jakobshavn isfjord in western greenland ii an independent and previously published 10 be production rate at jakobshavn isfjord and iii re measured 10 be concentrations from a baffin island calibration site that is included in the north eastern north america dataset combined we calculate a sea level high latitude 10 be production rate for the baffin bay region of 3 96 0 07 atoms g 1 a 1 lal stone scaling model after testing the baffin bay rate against calibration sites in norway and north eastern north america we calculate a more conservative arctic production rate of 3 96 0 15 atoms g 1 a 1 the baffin bay and arctic 10 be production rates are indistinguishable from the north eastern north america 10 be production rate 3 91 0 19 atoms g 1 a 1 and yield overall uncertainties of 2 3 7 1s these production rates reduce systematic uncertainties in 10 be based chronologies of ice margin change and allow 10 be based chronologies to be more confidently compared with high resolution climate records such as those from greenland ice cores copyright 2013 john wiley sons ltd

late glacial and holocene 10be production rates for western norway we present a new regional calibration of the 10be production rate from two well dated surfaces insouthern norway a rock avalanche with 14c dated wood and a precisely dated younger dryas moraine c

a knowledge based reactive transport approach for the simulation of biogeochemical dynamics in earth systems 1 a knowledge based reactive transport model kb rtm for simulation of coupled transport and biogeochemical transformations in surface and subsurface flow environments is presented http www geo uu nl kbrtm the scalable web distributed knowledge base kb which combines information technology it an automatic code generator and database management facilitates the automated construction of complex reaction networks from comprehensive information stored at the level of biogeochemical processes the reaction centric approach of the kb rtm system offers full flexibility in the choice of model components and biogeochemical reactions the procedure coupling the reaction networks to a generalized transport module into rtms is also presented the workings of our kb rtm simulation environment are illustrated by means of two examples of redox and acid base chemistry in a typical shelf sediment and an aquifer contaminated by landfill plumes

reactive transport modeling of the interaction between a high ph plume and a fractured marl the case of wellenberg abstract in the context of the proposed low and intermediate level radioactive waste repository at wellenberg switzerland calculations simulating the interaction between hyperalkaline solutions and a fractured marl at 25 c have been performed the aim of these calculations is to evaluate the possible effects of mineral dissolution and precipitation on porosity and permeability changes in such a fractured marl and their impact on repository performance solute transport and chemical reaction are considered in both a high permeability zone fracture where advection is important and the wall rock where diffusion is the dominant transport mechanism the mineral reactions are promoted by the interaction between hyperalkaline solutions derived from the degradation of cement a major component of the engineered barrier system in the repository and the host rock both diffusive dispersive and advective solute transport are taken into account in the calculations mineral reactions are described by kinetic rate laws the fluid flow system under consideration is a two dimensional porous medium marl 1 porosity with a high permeability zone simulating a fracture 10 porosity crossing the domain the dimensions of the domain are 6 m per 1 m and the fracture width is 10 cm the fluid flow field is updated during the course of the simulations permeabilities are updated according to kozeny s equation the composition of the solutions entering the domain is derived from modeling studies of the degradation of cement under the conditions at the proposed underground repository at wellenberg two different cases have been considered in the calculations these 2 cases are representative of 2 different stages in the process of degradation of cement ph 13 5 and ph 12 5 in both cases the flow velocity in the fracture diminishes with time due to a decrease in porosity this decrease in porosity is caused by the precipitation of calcite replacement of dolomite by calcite and other secondary minerals brucite sepiolite analcime natrolite tobermorite however the decrease in porosity and flow velocity is much more pronounced in the lower ph case the extent of the zone of mineral alteration along the fracture is also much more limited in the lower ph case the reduction of porosity in the fractures would be highly beneficial for repository performance since it would mean that the solutions coming from the repository and potentially carrying radionuclides in solution would have to flow through low conductive rock before they would be able to get to higher conductive features the biggest uncertainty in the reaction rates used in the calculations arises from the surface areas of the primary minerals additional calculations making use of smaller surface areas have also been performed the results show that the smaller surface areas and therefore smaller reaction rates result in a smaller reactivity of the system and smaller porosity changes

the laurentide and innuitian ice sheets during the last glacial maximum the late wisconsinan advance of the laurentide ice sheet started from a middle wisconsinan interstadial minimum 27 30 14 c ka bp when the ice margin approximately followed the boundary of the canadian shield ice extent in the cordillera and in the high arctic at that time was probably similar to present ice advanced to its late wisconsinan stage 2 limit in the northwest south and northeast about 23 24 14 c ka bp and in the southwest and far north about 20 21 14 c ka bp in comparison to some previous reconstructions of ice extent our current reconstruction has substantially more late wisconsinan ice in the high arctic where an innuitian ice sheet is generally acknowledged to have existed in the atlantic provinces where ice is now thought to have extended to the continental shelf edge in most places and on eastern baffin island where ice probably extended to the fiord mouths rather than to the fiord heads around most of the ice margin the late wisconsinan maximum ice extent either exceeded the extent of earlier wisconsinan advances or it was similar to the early wisconsinan advance ice marginal recession prior to 14 14 ck a bp occurred mainly in deep water and along the southern terrestrial fringe however heinrich event 1 probably drew down the entire central ice surface at 14 5 14 c ka bp sufficiently to displace the labrador sector outflow centre 900 km eastward from the coast of hudson bay the onset of substantial ice marginal recession occurred about 14 14 c ka bp in the northwest southwest and south but not until about 10 11 14 c ka bp in the northeast and in the high arctic thus the period of maximum ice extent in north america generally encompasses the interval from b24 21 to 14 14 c ka bp or considerably longer than the duration of the lgm defined as occurring during a period of low global sea level as well as during a time of relative climate stability b18 14 c ka bp the interval of advance of much of the laurentide ice sheet to its maximum extent between b27 14 c ka bp and b24 14 c ka bp coincides with a suggested interval of rapid fall in global sea level to near lgmlevels r 2001 elsevier science ltd all rights reserved

the deep accumulation of 10be at utsira southwestern norway implications for cosmogenic nuclide exposure dating in peripheral ice sheet landscapes cosmogenic nuclide exposure dating is a widely used method for constraining past ice sheet histories we scrutinize a recently published data set of cosmogenic 10be data from erratic boulders in norway used to constrain the deglaciation of the western scandinavian ice sheet to 20 ka our model of the 10be inventory in glacial surfaces leads us to conclude that the chronology may be afflicted by the deep subsurface accumulation of 10be during long lasting ice free periods that resulted in 10be ages 10 too old we suggest that the majority of the dated erratic boulders contain a uniform level of inherited muon produced 10be and were derived from bedrock depths 2 5 m and most likely 4 m the implication of our finding is that for landscapes that experience long ice free periods between brief maximum glacial phases glacial erosion of 5 m is required to remove detectable traces of inherited 10be

fjord insertion into continental margins driven by topographic steering of ice fjords line mountainous continental margins where icesheets and glaciers once stood a two dimensional model simulation suggests that fjords can be eroded within one million years primarily in response to topographic ice steering and erosion from ice discharge subsequent glaciers that form on these landscapes are smaller and exhibit greater responses to climate change

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

cementation of kerogen rich marls by alkaline fluids released during weathering of thermally metamorphosed marly sediments part i isotopic c o study of the khushaym matruk natural analogue central jordan abstract the khushaym matruk site in central jordan may represent a natural analogue depicting the interaction of alkaline solutions with a clayey sedimentary formation or with clay rich confining barriers at the interface with concrete structures in waste disposal sites in this locality past spontaneous combustion of organic matter in a clayey biomicritic formation produced a ca 60 m thick layer of cement marble containing some of the high temperature phases usually found in industrial cements e g spurrite brucite and ca aluminate a vertical cross section of the underlying sediments was used in order to study the interaction between cement marbles and neighbouring clayey limestones under weathering conditions a thermodynamic approach of the alteration parageneses calcite jennite afwillite brucite and csh phases in the cement marbles constrains the interacting solutions to have had ph values between 10 5 and 12 over 3 m the sediments located beneath the metamorphic unit were compacted and underwent carbonation they display large c and o isotopic variations with respect to pristine sediments from the bottom of the section low 13c values down to 31 4 pdb show the contribution of co2 derived from the oxidization of organic matter and from the atmosphere to the intense carbonation process affecting that particular sedimentary level the size of the c isotopic anomalies their geometrical extent and their coincidence with the variations of other markers like the zn content the structure of organic matter the mineralogical composition all argue that the carbonation process was induced by the percolation of high ph solutions which derived from the alteration of cement marbles the temperature of the carbonation process remains conjectural and some post formation o isotopic reequilibration likely affected the newly formed carbonate carbonation induced a considerable porosity reduction both in fractures and matrixes the khushaym matruk site may have some bearing to the early life of a repository site when water saturation of the geological formations hosting the concrete structures is incomplete enabling simultaneous diffusion of alkaline waters and gaseous co2 in the near field

marine 14c reservoir ages for 19th century whales and molluscs from the north atlantic abstract in order to compare radiocarbon dates on marine and terrestrial samples the former have to be corrected for a reservoir age we present reservoir ages from dating 21 whales collected 1860 1901 and recalculating dates of 23 molluscs collected 1857 1926 most of the whales were caught along the coast of norway but one is from france and one from iceland we assume the former mainly lived in the north and equatorial atlantic and in the norwegian sea whales feed only on pelagic organisms and will provide the reservoir age for the open ocean surface water however they travel long distances and will integrate the reservoir ages of the different water masses along their way molluscs dated from norway spitsbergen and arctic canada are stationary and monitor the sea water passing their dwelling site but some also take up carbon from particulate food or sediment pore water coastal water also often contains some continental carbon we present two different views on how to analyze and interpret the data mangerud recommends to use reservoir ages based on a combination of the whale and mollusc dates i e 380 30 and 360 30 yr relative to intcal04 and british oak respectively and a r value of 20 30 for the surface water in the n atlantic and norwegian sea bondevik and gulliksen maintain that the reservoir age and r along the norwegian coast is latitude dependant with r values increasing from 3 22 in the south to 105 24 at spitsbergen whales reflecting north atlantic open ocean surface water have lower r 7 11 than most molluscs

asynchronous response of marine terminating outlet glaciers during deglaciation of the fennoscandian ice sheet this is the accepted manuscript version published version is available at http dx doi org 10 1130 g35299 1

the deglaciation of the americas during the last glacial termination this paper reviews current understanding of deglaciation in north central and south america from the last glacial maximum to the beginning of the holocene together with paleoclimatic and paleoceanographic data we compare and contrast the pace of deglaciation and the response of glaciers to major climate events during the global last glacial maximum glgm 26 5 19 ka average temperatures decreased 4 to 8 c in the americas but precipitation varied strongly throughout this large region many glaciers in north and central america achieved their maximum extent during the glgm whereas others advanced even farther during the subsequent heinrich stadial 1 hs 1 glaciers in the andes also expanded during the glgm but that advance was not the largest except on tierra del fuego hs 1 17 5 14 6 ka was a time of general glacier thickening and advance throughout most of north and central america and in the tropical andes however glaciers in the temperate and subpolar andes thinned and retreated during this period during the bolling allerod interstadial b a 14 6 12 9 ka glaciers retreated throughout north and central america and in some cases completely disappeared many glaciers advanced during the antarctic cold reversal acr 14 6 12 9 ka in the tropical andes and patagonia there were small advances of glaciers in north america central america and in northern

mineralogical alteration and associated permeability changes induced by a high ph plume modeling of a granite core infiltration experiment abstract within the framework of the hpf project hyperalkaline plume in fractured rock at the grimsel test site switzerland a small scale core infiltration experiment was performed at the university of bern a high ph solution was continuously injected under a constant pressure gradient into a cylindrical core of granite containing a fracture this high ph solution was a synthetic version of solutions characteristic of early stages in the degradation of cement the interaction between the rock and the solutions was reflected by significant changes in the composition of the injected solution and a decrease in the permeability of the rock changes in the mineralogy and porosity of the fault gouge filling the fracture were only minor one dimensional reactive transport modeling using a modified version of the gimrt code was used to interpret the results of the experiment dispersive and advective solute transport mineral reaction kinetics and a coupling between porosity and permeability changes were taken into account in order to obtain a reasonable agreement between models and experimental results reactive surface areas of the order of 10 5 m 2 m 3 rock had to be used these values are much smaller than the values measured for the fault gouge filling the fracture which are in the order of 10 6 10 7 m 2 m 3 rock however the results could be improved by adding a small fraction of fine grained mineral which could explain the high initial peaks in al and si concentration with the inclusion of this fine grained fraction the initial surface areas in the model were within the range of the measured specific surface areas of the fault gouge the fact that the decrease in permeability was significant despite the minor changes in mineralogy suggests that permeability may be controlled by changes in the structure of the rock pore geometries rather than by only the bulk volumetric porosity changes

two terrestrial records of rapid climatic change during the glacial holocene transition 14 000 9 000 calendar years b p from europe two independent multidisciplinary studies of climatic change during the glacial holocene transition ca 14 000 9 000 calendar yr b p from norway and switzerland have assessed organism responses to the rapid climatic changes and made quantitative temperature reconstructions with modern calibration data sets transfer functions chronology at krakenes western norway was derived from calibration of a high resolution series of 14c dates chronologies at gerzensee and leysin switzerland were derived by comparison of 18o in lake carbonates with the 18o record from the greenland ice core project both studies demonstrate the sensitivity of terrestrial and aquatic organisms to rapid temperature changes and their value for quantitative reconstruction of the magnitudes and rates of the climatic changes the rates in these two terrestrial records are comparable to those in greenland ice cores but the actual temperatures inferred apply to the terrestrial environments of the two regions

changes in north atlantic radiocarbon reservoir ages during the allerod and younger dryas estimates of the radiocarbon age of seawater are required in correlations between marine and terrestrial records of the late quaternary climate we radiocarbon dated marine shells and terrestrial plant remains deposited in two bays on norway s west coast between 11 000 and 14 000 years ago a time of large and abrupt climatic changes that included the younger dryas yd cold episode the radiocarbon age difference between the shells and the plants showed that sea surface reservoir ages increased from 400 to 600 years in the early yd stabilized for 900 years and dropped by 300 years within a century across the yd holocene transition

quaternary glaciations in southern fennoscandia evidence from southwestern norway and the northern north sea region abstract based on records from the northern north sea and southern norway quaternary fennoscandian glaciations are described and discussed maximum glaciation defined as the presence of shelf edge glaciation an ice stream flowing out of the norwegian channel and most likely an ice divide over the central part of fennoscandia sweden gulf of bothnia occurred for the first time in the late cenozoic at ca 1 1 myr the fedje glaciation this glaciation was followed by a ca 600 kyr period with at least two glaciations with ice extension somewhat larger than the younger dryas event in the region the first maximum glaciation of the bruhnes chron was during isotope stage 12 and was followed by repeated maximum glaciations within each of the light isotopic stages until stage 2 during the weichselian the southwestern part of the fennoscandian ice sheet reached maximum position three times sometime between 22 and 28 37 and 50 and 60 and 80 ka limited glaciations probably occurred during stadials between the early and middle weichselian interstadials between 500 ka and 1 1 myr and most likely also prior to 1 1 myr deep norwegian sea ice rafted detritus ird records reflecting contributions from several different ice sheets fennoscandian barents sea iceland and greenland each with large variations in history of ice extent to their respective margins yet to some degree they reflect the glaciation of the northern north sea region with an increasing ird input around 1 1 myr and a relatively low input of north sea components during some cycles around the b m boundary maximum glaciations occurred during insolation minima in the earlier part of the middle pleistocene however not all such minima are reflected by maximum glaciation in southern parts of fennoscandia the relatively poor chronological control and non continuous character of the data on weichselian interstadials stadials precludes a clear relationship to atmospheric changes recorded in greenland ice cores as well as to precession and or obliquity cycles in insolation

late weichselian vegetation climate and floral migration at liastemmen north rogaland south western norway palynological results from liastemmen indicate a tripartite division of the late weichselian in the pleniglacial period from deglaciation ca 14000 bp to ca 13000 bp artemisia dominated pioneer vegetation on disturbed mineral soil was strongly influenced by cold winters and katabatic winds the late weichselian interstadial ca 13000 bp ca 11000 bp comprises a salix shrub consolidation phase and from ca 12700 bp a tree birch phase in the last 500 years of this period july and january means are estimated to about 16 c and between 2 c and 6 c respectively in the younger dryas stadial ca 11000 bp ca 10200 bp artemisia dominated vegetation returns three brief climatic deteriorations ca 12 250 bp 11 700 bp and 11 300 bp unfavourable to woody vegetation on humus soils are demonstrated within the interstadial critical climatic factors include cool winters and strong winds exposing vegetation and soil to frost drought and erosion the oldest and strongest oscillation probably involving local deforestation is correlated with the older dryas deterioration boreal circumpolar eurasiatic and arctic alpine plants dominated the late glacial flora for the majority of the late glacial taxa a northward migration is demonstrated this may also apply for papaver radicatum pinguicula alpina and primula scandinavica all with bicentric distributions in norway today

analysis of the degree of contamination and evolution in the last 100 years of the composition of the bed sediments of the anllons basin in this study five cores of the anllons river bed sediments were analyzed in order to evaluate the downcore and downstream variations in their chemical composition the first step was the evaluation of the metal distribution in the bulk 2 mm and fine fractions 63 m the analysis revealed that most of the metals followed the same trend in both fractions although the fine fraction presented usually higher concentrations however the concentration of both fractions tended to equalize with increasing contamination no general increase was observed in the metal concentrations toward the surface which could be attributed to recent anthropogenic contributions instead the distributions were homogeneous or peaked at various depths downcore the most important historical feature was observed at the mouth of the river at 96 cm depth corresponding to the end of the eighteenth century upcore increased metal concentrations in parallel with increased fine fraction occurred from this depth which were attributed to a bridge construction and consequent changes in sediment dynamics as the metal concentrations can be influenced by variations in texture or other sediment characteristics the second step was to evaluate the efficiency of several normalized indexes in the assessment of the degree of contamination by calculating the enrichment factor ef the geoaccumulation index igeo and the pollution load index pli the efs obtained were 10 thus revealing little anthropogenic inputs to the basin the igeo produced higher values when compared with the efs instead of absolute ef or igeo absolute values the use of cumulative probability plots allowed identifying more accurately potential outliers indicating contamination only one population was identified for zn and pb with a reduced number of outliers at the highest concentrations for pb as shown a more complex plot with the outliers identified at c4 and c5 finally the pli allowed determining the absence of a significant contamination in the bed sediments the bioavailable and non geogenic fractions contribute up to a 90 of the total concentrations in the case of as and cu and showed similar dissimilar profiles in comparison with total metals also the quality guidelines were surpassed so the high solubility of as zn pb and ni in the sediments revealed the need to monitor the bed sediment quality of the anllons river

geothermal spring causes arsenic contamination in river waters of the southern tibetan plateau china large numbers of as enriched geothermal springs are distributed at the southern tibetan plateau and their influence on river water is still not clear lhasa river and its tributary duilong qu located at downstream of the largest geothermal spring of the tibetan plateau were selected for sampling during monsoon and non monsoon seasons dissolved trace elements b cr ni cu zn as cs ba and u were measured in river water samples by icp ms the results show that due to contribution of geothermal spring as levels of duilong qu 205 6 g l and lhasa river 12 7 g l were higher during non monsoon season than that of who guideline for drinking water 10 g l accordingly as level of river water was lower during the monsoon season than that of the non monsoon season due mainly to dilution process therefore although tibetan rivers are generally considered as free of contamination geothermal springs cause as contamination of river water at some local regions and may harm the local residents further research is needed in other parts of the plateau to determine whether as level of groundwater of the related region is high

landform assemblages and sedimentary processes along the norwegian channel ice stream abstract several regional and detailed bathymetric datasets together with 2d and 3d seismic data are compiled to investigate the landform assemblages and sedimentary processes along the former path of the norwegian channel ice stream ncis at the broad scale the glacial geomorphology and sedimentary architecture reveals three different zones along the ice stream path characterized by 1 glacial erosion in the onset zone and inner shelf area 2 sediment transport through the main trunk of the ice stream across the mid shelf and 3 a zone of deposition towards the outer continental shelf edge along the first 400 km of the ice stream bed outer oslofjord skagerrak stavanger a major overdeepening is associated with suites of crag and tail features at the transition from the crystalline bedrock to the sedimentary bedrock together with evidence of glaciotectonic thrusting in the form of hill hole pairs here we interpret extensive erosion of both sedimentary rocks and quaternary sediments this zone is succeeded by an approximately 400 km long zone through which most of the sediments eroded from the inner shelf were transported rather than being deposited we infer that sediment was transported subglacially and is likely to have been advected downstream by soft sediment deformation the thickness of till of inferred weichselian age generally varies from 0 and 50 m and this zone is characterized by mega scale glacial lineations msgls which we interpret to be formed in a dynamic sedimentary system dominated by high sediment fluxes but with some localized sediment accretion associated with lineations towards the shelf break the north sea fan extends to the deep norwegian sea and reflects massive sedimentation of glacigenic debris onto the continental slope numerous glacigenic debris flows accumulated and constructed a unit up to 400 m thick during the last glacial maximum the presence of these three zones erosion transport deposition is consistent with observations from other palaeo ice streams and their significance arises from their potential to feedback and impact on ice stream dynamics

too young or too old evaluating cosmogenic exposure dating based on an analysis of compiled boulder exposure ages cosmogenic exposure dating has greatly enhanced our ability to define glacial chronologies spanning several global cold periods and glacial boulder exposure ages are now routinely used to constrai

high resolution record of northern hemisphere climate extending into the last interglacial period high resolution record of northern hemisphere climate extending into the last interglacial period

dansgaard oeschger cycles interactions between ocean and sea ice intrinsic to the nordic seas dansgaard oeschger d o cycles are the most dramatic frequent and wide reaching abrupt climate changes in the geologic record on greenland d o cycles are characterized by an abrupt warming of 10 5 c from a cold stadial to a warm interstadial phase followed by gradual cooling before a rapid return to stadial conditions the mechanisms responsible for these millennial cycles are not fully understood but are widely thought to involve abrupt changes in atlantic meridional overturning circulation due to freshwater perturbations here we present a new high resolution multiproxy marine sediment core monitoring changes in the warm atlantic inflow to the nordic seas as well as in local sea ice cover and influx of ice rafted debris in contrast to previous studies the freshwater input is found to be coincident with warm interstadials on greenland and has a fennoscandian rather than laurentide source furthermore the data suggest a different thermohaline structure for the nordic seas during cold stadials in which relatively warm atlantic water circulates beneath a fresh surface layer and the presence of sea ice is inferred from benthic oxygen isotopes this implies a delicate balance between the warm subsurface atlantic water and fresh surface layer with the possibility of abrupt changes in sea ice cover and suggests a novel mechanism for the abrupt d o events observed in greenland ice cores

a calendar age estimate of a very late younger dryas ice sheet maximum in western norway abstract we have established an accurate chronology in calendar years for the maximum phase of the younger dryas yd scandinavian ice sheet in western norway glaciomarine silt confidentially identified in shallow marine basins located was 1 2 km distal to a yd ice marginal delta due to the topography of this area the silt monitors faithfully the period when the ice sheet reached and remained at its maximum position in these basins the deposition of silt commenced 6 10 cm above the vedde ash bed ca 10 300 14 c yr bp or ca 12 000 cal yr bp according to calculated sedimentation rates of the deposits the deposition of silt started and thus the ice sheet reached its maximum 300 400 years after the vedde ash fall around 11 600 11 700 cal yr bp the ice sheet receded from its maximum position simultaneously with the increase of betula birch pollen at the yd holocene boundary ca 11 500 cal yr bp the duration of the yd glacial maximum of the scandinavian ice sheet in western norway was only about 100 200 years and is constrained within the 14 c plateau at 10 000 14 c yr bp the yd glacial maximum occurred extremely late in western norway later than elsewhere in scandinavia the result also demonstrates different response times for different glaciers small cirque glaciers farther north in western norway expanded to their maximum position very early in the yd whereas the ice cap at alfotbreen reached its maximum later but still before the vedde ash fall the ice sheet reached its maximum well after the vedde ash fall and only 100 200 years before the yd holocene boundary

the jaeren area a border zone of the norwegian channel ice stream abstract the coastal lowlands of jaeren southwestern norway have an extensive cover of quaternary sediments lithological biostratigraphical and geochronological investigations of a series of boreholes across jaeren have allowed us to combine earlier and new information on these deposits into a temporal model of quaternary sedimentation the cores show evidence of at least four ice free episodes with marine deposition during mainly arctic conditions the oldest of these is considered to be ca 200 ka old and the youngest one is the sandnes interstadial which is 14 c ams dated to 32 ka bp interbedded between these units are 10 40 m thick units of till with components of marine material these findings together with a re evaluation of distinct morphological features on jaeren as well as earlier provenance studies strongly suggest that jaeren has been a boundary zone between an ice stream following the norwegian channel draining a substantial part of the southern region of the fennoscandian ice sheet and local ice from south western norway through multiple periods of glaciation starting ca 1 1 myr million years ago the norwegian channel ice stream has been the main conduit of erosion products from southern scandinavia to the deep norwegian sea comparison with ice stream profiles from antarctica suggests that the deposition of relatively young marine sediments as high as ca 200 m a s l on jaeren is a result of glacial isostasy rather than regional tectonic movements

a 10be chronology of south western scandinavian ice sheet history during the lateglacial period we present 34 new cosmogenic 10be exposure ages that constrain the lateglacial bolling preboreal history of the scandinavian ice sheet in the lysefjorden region south western norway we find that the classical lysefjorden moraines earlier thought to be entirely of younger dryas age encompass three adjacent moraines attributed to at least two ice sheet advances of distinctly different ages the 10be age of the outermost moraine 14 0 0 6 ka n 4 suggests that the first advance is of older dryas age the innermost moraine is at least 2000 years younger and was deposited near the end of the younger dryas 11 4 0 4 ka n 7 after abandonment of the innermost lysefjorden moraine the ice front receded quickly towards the head of the fjord where recession was interrupted by an advance that deposited the trollgaren moraine at 11 3 0 9 ka n 5 10be ages from the inboard side of the trollgaren moraine suggest final retreat by 10 7 0 3 ka n 7 the late culmination of the younger dryas advance contrasts with other sectors of the scandinavian ice sheet where the margin appears to have culminated earlier during the younger dryas stadial followed by retreat during the middle and late part of the younger dryas

precise 14c ages of the vedde and saksunarvatn ashes and the younger dryas boundaries from western norway and their comparison with the greenland ice core gicc05 chronology the greenland ice cores with the gicc05 chronology represent a standard for late quaternary climate events and their ages whereas many other palaeoclimatic archives are dependent on 14 c dates it is therefore critical to know if the ice core and the calibrated 14 c chronologies are identical and if not to quantify the offset between them we present bayesian age depth modelling of 118 accelerator mass spectrometry 14 c dates from kraukenes lake calibrated using intcal09 that provide high precision ages of 12 066 42 and 10 210 35 cal a bp for the vedde and saksunarvatn ashes respectively the lower and upper younger dryas boundaries have ages of 12 710 52 and 11 546 59 cal a bp respectively the four dated levels coincide with correlative levels in gicc05 within the dating uncertainties but are all consistently younger at kraukenes the ages of the tephra chronostratigraphic markers suggest a mean offset of 70 years to older ages in the gicc05 compared with the intcal09 time scale responses to small climate changes 30 years before the younger dryas boundaries at kraukenes are suggested to correspond to the defined greenland stadial 1 boundaries this suggested difference in timing 30 years and time scale offset 70 years mean that the greenland stadial 1 boundaries appear 100 years older than the younger dryas boundaries copyright 2013 john wiley sons ltd

erratum late glacial and holocene 10be production rates for western norway 1 calculation of the sea level high latitude production rate based on the samples from the herdla halsnoy younger dryas end moraine required accounting for the isostatic rebound of the site following deglaciation lohne et al 2007 in the process of calculating exposure ages of samples from nearby sites it was realized that the original calibration of the production rates from halsnoy were calculated using a correction based on the relative sea level history 70m maximum plus the eustatic sea level history 50m at maximum i e that the amount of isostatic depression had been over corrected sea level high latitude be production rates based on the correct relative sea level history are presented below in a corrected version of table 2 2 in the original publication the combined production rates were determined using a chi squared minimization based on the data from both calibration sites however because the two studied sites have significantly different ages halsnoy 11650 100 and oldedalen 6070 111 and therefore integrate production over different lengths of time it is inappropriate to determine a sea level high latitude production rate for the entire data set using the chi squared minimization instead the arithmetic mean of the production rates from the two sites is the more appropriate average production rate we present in the corrected table 2 below both the updated production rate values for the samples from halsnoy and average production rates using the arithmetic mean and standard deviation of the production rates from the two sites we apologize for any inconvenience caused references

deglaciation of fennoscandia abstract to provide a new reconstruction of the deglaciation of the fennoscandian ice sheet in the form of calendar year time slices which are particularly useful for ice sheet modelling we have compiled and synthesized published geomorphological data for eskers ice marginal formations lineations marginal meltwater channels striae ice dammed lakes and geochronological data from radiocarbon varve optically stimulated luminescence and cosmogenic nuclide dating this is summarized as a deglaciation map of the fennoscandian ice sheet with isochrons marking every 1000 years between 22 and 13 cal kyr bp and every hundred years between 11 6 and final ice decay after 9 7 cal kyr bp deglaciation patterns vary across the fennoscandian ice sheet domain reflecting differences in climatic and geomorphic settings as well as ice sheet basal thermal conditions and terrestrial versus marine margins for example the ice sheet margin in the high precipitation coastal setting of the western sector responded sensitively to climatic variations leaving a detailed record of prominent moraines and other ice marginal deposits in many fjords and coastal valleys retreat rates across the southern sector differed between slow retreat of the terrestrial margin in western and southern sweden and rapid retreat of the calving ice margin in the baltic basin our reconstruction is consistent with much of the published research however the synthesis of a large amount of existing and new data support refined reconstructions in some areas for example the lgm extent of the ice sheet in northwestern russia was located far east and it occurred at a later time than the rest of the ice sheet at around 17 15 cal kyr bp we also propose a slightly different chronology of moraine formation over southern sweden based on improved correlations of moraine segments using new lidar data and tying the timing of moraine formation to greenland ice core cold stages retreat rates vary by as much as an order of magnitude in different sectors of the ice sheet with the lowest rates on the high elevation and maritime norwegian margin retreat rates compared to the climatic information provided by the greenland ice core record show a general correspondence between retreat rate and climatic forcing although a close match between retreat rate and climate is unlikely because of other controls such as topography and marine versus terrestrial margins overall the time slice reconstructions of fennoscandian ice sheet deglaciation from 22 to 9 7 cal kyr bp provide an important dataset for understanding the contexts that underpin spatial and temporal patterns in retreat of the fennoscandian ice sheet and are an important resource for testing and refining ice sheet models

evidence of early deglaciation 18 000 cal a bp and a postglacial relative sea level curve from southern karmoy south west norway

age of the fjord stade moraines in the disko bugt region western greenland and the 9 3 and 8 2 ka cooling events abstract retreat of the western greenland ice sheet during the early holocene was interrupted by deposition of the fjord stade moraine system the fjord stade moraine system spans several hundred kilometers of western greenland s ice free fringe and represents an important period in the western greenland ice sheet s deglaciation history but the origin and timing of moraine deposition remain uncertain here we combine new and previously published 10 be and 14 c ages from disko bugt western greenland to constrain the timing of fjord stade moraine deposition at two locations 60 km apart at jakobshavn isfjord the northern of two study sites we show that jakobshavn isbrae advanced to deposit moraines ca 9 2 and 8 2 8 0 ka in southeastern disko bugt the ice sheet deposited moraines ca 9 4 9 0 and 8 5 8 1 ka our ice margin chronology indicates that the greenland ice sheet in two distant regions responded in unison to early holocene abrupt cooling 9 3 and 8 2 ka as recorded in central greenland ice cores although the timing of fjord stade moraine deposition was synchronous in jakobshavn isfjord and southeastern disko bugt within uncertainties we suggest that jakobshavn isbrae advanced while the southeastern disko bugt ice margin experienced stillstands during the 9 3 and 8 2 ka events based on regional geomorphology and the distribution of 10 be ages at each location the contrasting style of ice margin response was likely regulated by site specific ice flow characteristics jakobshavn isbrae s high ice flux results in an amplified ice margin response to a climate perturbation both warming and cooling whereas the comparatively low flux sector of the ice sheet in southeastern disko bugt experiences a more subdued response to climate perturbations our chronology indicates that the western greenland ice sheet advanced and retreated in concert with early holocene temperature variations and the 9 3 and 8 2 ka events although brief were of sufficient duration to elicit a significant response of the western greenland ice sheet

collapse of marine based outlet glaciers from the scandinavian ice sheet abstract we present a reconstruction of the timing and retreat rates of more than 2000 m thick younger dryas yd fjord glaciers in western norway using a detailed chronology of 10 be exposure ages from lateral moraines and 14 c dated end moraines a primary conclusion is that ice margins retreated up the 120 170 km long fjords at mean rates of 240 340 m yr 1 during the early holocene we further show that part of the south western sector of the scandinavian ice sheet collapsed in two distinct steps the first step occurred between 19 5 and 18 5 ka bp as break up of the norwegian channel ice stream which drained the ice sheet during the last glacial maximum lgm the second step was the rapid retreat up the fjords mentioned above dated to 11 6 11 1 ka bp during the intervening 7000 years no net retreat occurred despite oscillations of the ice margin this stepwise ice margin retreat strongly contrasts with the more monotonic decay of the ice sheet as a whole indicating that water depths set the pace for climate triggered ice margin retreat in this part of the ice sheet calving and melting of marine margins has dominated mass loss from modern ice sheets in recent decades however the mechanisms and long term 100 1000 yr rate of ice front retreat is less certain and empirical examples such as those given here may help in developing better numerical models

evaluation of elemental enrichments in surface sediments off southwestern taiwan surface slices of 20 sediment cores off south western taiwan and bed sediment of river kaoping were measured for major and trace elements al as ca cd cl cr cu fe k mg mn na ni p pb s si ti v and zn to evaluate the geochemical processes responsible for their distribution including elemental contamination major element al ratio and mean grain size indicate quartz dominated coarse grained sediments that likely derived from sedimentary rocks of taiwan and upper crust of yangtze craton bi plot of sio2 versus fe2o3 suggests the possible iron enrichment in sediments of slag dumping sites highest concentrations of cr mn p s and zn found in sediments of dumping sites support this correlation analysis shows dual associations detrital and organic car bon for cr p s and v with the latter association typical for sediments in dumping sites normalization of trace elements to al indicates high enrichment factors 2 for as cd pb and zn revealing contamination factor analysis extracted four geochemical associations with the principal factor accounted for 25 1 of the total variance and identifies the combined effects of dumped iron and steel slag induced c s fe relationship owing to authigenic precipitation of fe mn oxyhydroxides and or metal sul fides and organic matter complexation of fe mn ca cr p and v factors 2 3 and 4 reveal detrital association ti al ni pb cu and v effect of sea salt cl mg na and k and anthropogenic component as and zn carbonate link respectively in the investigated sediments

lateglacial retreat chronology of the scandinavian ice sheet in finnmark northern norway reconstructed from surface exposure dating of major end moraines abstract we report results from a comprehensive surface exposure dating campaign in eastern finnmark located in the northernmost part of norway and close to the norwegian russian border this is a palaeo glaciologically important region as it sits near the proposed border zone between the former scandinavian and barents sea ice sheets however until now the deglaciation history has few direct dates onshore and the chronology of ice front retreat is instead found by correlating ice marginal deposits with isostatically raised shorelines and marine sediment cores we measured the content of 10 be n 22 and 36 cl n 17 from boulders located at the crest of major moraine ridges at four localities kjaes kongsfjorden vardo and kirkenes these are key localities of existing regional reconstructions of ice recession in this area despite some spread in age results from each locality due to methodological challenges associated with surface exposure dating the large numbers of samples from each site except kjaes still allow for obtaining clusters of similar ages which are used for arriving at a likely chronology of ice front retreat our results show that the kongsfjorden and vardo moraines were deposited 14 3 1 7 ka and 13 6 1 4 ka respectively and thus point to a older dryas age of the proposed outer porsanger deglaciation sub stage moraine ridges belonging to the main sub stage near kirkenes were dated to 11 9 1 2 ka corresponding well with the ice retreat chronology farther west in northern norway and suggesting that the maximum younger dryas ice sheet extent was attained in the late younger dryas along a more than 500 km long stretch in northernmost scandinavia

a geochemical assessment of the middle and lower mvoti river system kwazulu natal south africa this paper presents one of the first investigations into the geochemical enrichment of the middle and lower mvoti river system chemical elements are naturally present in aquatic sediments but their concentrations tend to rise to potentially toxic levels via both natural and anthropogenic processes this study evaluated the concentrations of aluminum arsenic boron barium cadmium calcium cobalt chromium copper iron lead magnesium manganese molybdenum nickel phosphorous selenium silicon strontium titanium vanadium and zinc using inductively coupled plasma optical emission spectroscopy the levels of elements present were used to assess their spatial distribution within the river and to determine the contamination factors and enrichment factors for each element the pollution load index pli is another contributing parameter that was calculated to determine the degree of pollution at each site the results indicate that the sediments of the mvoti are low to moderately polluted and deteriorating with time average pli value of 5 19 and that a major contributing factor to this contamination is natural sources

two dimensional reactive transport modeling of the alteration of a fractured limestone by hyperalkaline solutions at maqarin jordan abstract two dimensional reactive transport modeling of the maqarin eastern springs site a natural analogue for the alteration of a fractured limestone by high ph portland cement waters has been performed using the crunchflow code these 2d calculations included transport by advection dispersion diffusion along a single fracture and diffusion in the wall rock solute transport was coupled to mineral dissolution and precipitation a limited sensitivity analysis evaluated the effect of different values of primary mineral surface areas flow velocity and sulfate concentration of the inflowing high ph solution major secondary minerals include ettringite thaumasite c s h c a s h and calcite c s h c a s h precipitation is controlled by the dissolution of primary silicates ettringite precipitation is controlled by diffusion of sulfate and aluminum from the wall rock to the fracture with aluminum provided by the dissolution of albite calcite precipitation is controlled by diffusion of carbonate from the wall rock extents of porosity sealing along the fracture and in the fracture wall rock interface depend on assumptions regarding flow velocity and composition of the high ph solution the multiple episodes of fracture sealing and reactivation evidenced in the fracture infills were not included in the simulations results can qualitatively reproduce the reported decrease in porosity in the fractures and in the wall rock next to the fractures instances of porosity increase next to fractures caused by carbonate dissolution were not reproduced by the calculations

submarine landforms and the reconstruction of fast flowing ice streams within a large quaternary ice sheet the 2500 km long norwegian svalbard margin 57 80 n morphological interpretation of regional and detailed bathymetric data sets on the 2500 km long norwegian shelf from the north sea 57 n to svalbard 80 n has revealed a dynamic ice flow pattern along the western marginof the scandinavian and barents svalbard ice sheets about 20 cross shelf troughs with megascale glacial lineations msgl elongate ridges and grooves oriented parallel to trough long axes are interpreted as former pathways for fast flowing ice streams studies of large scale margin morphology and seismic profiles have identified large submarine fans at the mouths of several major cross shelf troughs less dynamic ice probably existed on shallower banks the two largest paleo ice streams were the norwegian channel ice stream and bear island trough ice stream each 150 200 km wide at the mouth the lengths of individual msgl vary from hundreds of meters to several tens of kilometers and the distance between ridges varies from 0 1 to 3 km msgl amplitudes reach 15 m but are commonly 10 m the onset of msgl and hence fast ice flow is generally close to the outer coast at the border zone between crystalline rocks and softer sedimentary rocks transverse submarine ridges on various scales commonly parallel to the shelf edge reflect either the maximum ice sheet position or the recessional pattern of the ice sheet lateral ice stream moraines several tens of kilometers long have also been mapped along the sides of several cross shelf troughs identifying the border zone between fast ice flow and stagnant or slow flowing ice on intervening banks

submarine slide scars and mass movements in karmsundet and skudenesfjorden southwestern norway morphology and evolution abstract shallow seismic sections multibeam bathymetric images and geotechnical investigations of the seafloor in karmsundet and skudenesfjorden sw norway have revealed the occurrence of large slide scars and associated mass movement deposits the slide escarpments are up to 30 40 m high and 8 km long with up to 20 10 6 m 3 of sediment released during a single event of retrogressive sliding the slide scars show a range of associated seafloor topography reflecting various modes of sediment displacement the variation in the escarpment morphology and sediment deformation style can be attributed to the varied intensity of liquefaction sliding involved mud deposits of allerod younger dryas to early holocene age but partly also deposits older than ca 12 000 14 c years bp the sediment failures were probably triggered by seismic reactivation of a local fault by postglacial regional isostatic rebound prior to failure the seafloor deposits were undercompacted and metastable due to high pore pressure the presence of shallow gas and the relatively steep local slope created by the formation of a major scour trough by sea currents minor gravitational sliding may still occur along some of the escarpments although engineering slope stability analysis indicates that the deposits can be regarded as stable in the present day conditions of static load and the anticipated weak sporadic earthquakes with an occurrence likelihood of 10 4 year and a peak acceleration of 0 25 g

elevation changes of the fennoscandian ice sheet interior during the last deglaciation the dynamics of ice sheet interiors during the last deglaciation are poorly constrained hindering evaluation of ice sheet models we provide direct evidence of fennoscandian ice sheet fis interior behaviour during deglaciation through surface exposure dating our results demonstrate early thinning of the fis prior to the younger dryas yd 12 8 11 7 ka interior thinning in central norway was concurrent with retreat along the coastline exposing ice free mountainous tracts potentially as early as 20 15 ka the fis then formed moraines in these ice free tracts during the yd this is contrary to current hypotheses advocating a landscape fully covered by cold inactive ice during this period present empirical and model reconstructions fail to capture rapid interior down wastage increasing uncertainties in ice sheet volume estimates and sea level contributions

influence of reaction kinetics and mesh refinement on the numerical modelling of concrete clay interactions large quantities of cements and concretes need to be incorporated in geological disposal facilities for long lived radwaste an alkaline plume diffusing from an aged concrete ph 12 5 through argillite type rocks has been modelled considering feedback of porosity value variations on transport properties using the reactive transport code toughreact the mineralogical composition of the argillite is modified at the interface with the concrete diffusion of cementitious elements leads to rapid and strong porosity occlusion in the argillite numerical results show that both reaction rates and spatial refinement affect mineralogical transformation pathways the variations in porosity and the extension of the zone affected by the alkaline perturbation are compared at different times the major effects of mineral precipitation under kinetic constraints rather than local equilibrium are a delay in the porosity clogging and an increase in the extension of the alkaline perturbation in the clay formation the same time delay rise for the porosity occlusion also appears for the roughest spatial resolutions a simulation as representative as possible of temporal and spatial scales of cementation processes must then be supported by more comparative data such as long term experimental investigations or natural analogues

timing of the younger dryas glacial maximum in western norway this study precisely constrains the timing of the younger dryas yd glacial maximum in south western norway by utilizing sediment records from lake basins two of the basins located on the distal side of the mapped herdla halsnoy moraine received meltwater directly from the ice sheet only when the ice margin reached its maximum extent during the yd in the cores the ice maximum is represented by well defined units with meltwater deposits dominantly laminated silt plant macrofossils in the sediment sequences are common and we obtained 18 radiocarbon ages from one of the cores by applying bayesian age depth modelling we obtained a precise date for this meltwater event and thereby also for the timing of the yd glacial maximum we conclude that the ice sheet advance culminated at the halsnoy moraine at 11 760 120 cal a bp and that the ice margin stayed in this position for 170 120 years the subsequent retreat started at 11 590 100 cal a bp i e close to the yd holocene boundary withdrawal was probably triggered by abrupt climatic warming at this time copyright 2011 john wiley sons ltd

heavy metal mobility assessment in sediments from the odiel river iberian pyritic belt using sequential extraction the tessier sequential extraction scheme ses was applied to sediments from the odiel river catchment iberian pyritic belt sw of spain one of the most acid rivers on earth to assess the chemical association exchangeable carbonatic bound to manganese and iron oxides bound to organic matter and residual mineral of heavy metals zn cd pb cu cr mn ni fe and hg sediments are very heterogeneous in their textural characteristics showing different grain size twenty seven samples were studied from from areas along the odiel river from the source to the mouth with special interest in the odiel marshes natural park due to its ecological significance samples were classified as sandy especially at the river mouth with low iron oxide and organic matter content and clay silty in the middle of the river catchment with high iron oxide content the numerous sandy samples with low ph values explain the low levels of metals upstream although potential metals contributions arise from mining and ore however the presence of sulfate in the mining area and carbonate at the mouth may explain the high presence of lead and iron in these sandy zones some percentage of mobile ni cu and zn were detected in the mining area but the elevated relative percentage of exchangeable cd in the estuary is even more remarkable the percentage of zn bound to carbonate is considerable in the catchment but especially in the estuary however cu is only detected in the carbonate phase downstream in spite of the low concentration of carbonate which represents a drawback in the application of the tessier ses to these types of samples finally relatively high percentages of residual non mobile hg and pb were observed in the estuarine and mining areas respectively sand lime and clay fractions of representative samples from areas i ii and iii were used in a metal speciation study mainly the elements analyzed had accumulated in the non residual fractions in the mining area of the pyrite belt the elements analyzed are mainly bound to fe mn oxides fe mn cu cr pb mn zn and the organic matter sulfide fraction ni zn hg cd independent of sediment grain size in conclusion we show that the results of the study of chemical speciation in sediments from acid rivers are independent of the sediment grain size considered

atmospheric scaling of cosmogenic nuclide production climate effect 1 absorption of cosmic rays by atmospheric mass varies temporally due to a redistribution of atmospheric pressure by ice sheets during glaciations the compression and expansion of the atmosphere due to cooling and warming and changes in katabatic winds near large ice masses these atmospheric processes can result in changes in production rates of cosmogenic nuclides which when integrated over long exposure durations may result in 0 to 5 adjustments in site production rates depending on location combining a ccm3 model with imbedded ice sheets for 20 ka we show that production rates changes relative to today are greatest at high elevations 6 7 at 5 km altitude due to atmospheric compression from decreased temperature production rates at specific times for sites near ice sheet margins can be reduced more than 10 due to a combination of katabatic winds draining off the ice sheet margins and atmospheric cooling nunatak settings may be significantly affected by the climate effect due to persistent glacial atmospheric conditions atmospheric variability may explain some of the disparities among cosmogenic nuclide production rate calibrations

high ph plume from low alkali cement fracture grouting reactive transport modeling and comparison with ph monitoring at onkalo finland grouting of water conducting fractures with low alkali cement is foreseen for the potential future repository for spent nuclear fuel in finland onkalo site a possible consequence is the formation of high ph solutions which will be able to react with the host rock calculations have been performed including the hydration and simultaneous leaching of the grout the effect of different possible groundwater compositions has been studied the results show that after grouting the duration of the initial high ph peak is short 0 5 a which compares well with observations at a test borehole magnesium in the groundwater induces the precipitation of brucite at the grout fracture interface which consumes oh in the longer term the results show a gradually decaying ph tail ph 9 controlled by the precipitation of calcite at the grout fracture interface the duration of this tail correlates inversely with the carbonate content of the inflowing groundwater a major finding of this study is that mineral precipitation controls the formation of a potential high ph plume by consuming alkalinity and limiting diffusive solute exchange between the grout and the circulating groundwater as a consequence assumption of long term interaction between rocks or engineering barrier materials with flowing high ph 12 solutions may not be very realistic

early break up of the norwegian channel ice stream during the last glacial maximum 10be dating last glacial maximum abstract we present 18 new cosmogenic 10 be exposure ages that constrain the breakup time of the norwegian channel ice stream ncis and the initial retreat of the scandinavian ice sheet from the southwest coast of norway following the last glacial maximum lgm seven samples from glacially transported erratics on the island utsira located in the path of the ncis about 400 km up flow from the lgm ice front position yielded an average 10 be age of 22 0 2 0 ka the distribution of the ages is skewed with the 4 youngest all within the range 20 2e20 8 ka we place most confidence on this cluster of ages to constrain the timing of ice sheet retreat as we suspect the 3 oldest ages have some inheritance from a previous ice free period three additional ages from the adjacent island karmoy provided an average age of 20 9 0 7 ka further supporting the new timing of retreat for the ncis the 10 be ages from utsira and karmoy suggest that the ice stream broke up about 2000 years earlier than the age assignment based on 14 c ages on foraminifera and molluscs from marine sediment cores we postulate that the scandinavian ice sheet flowed across the norwegian channel to denmark and onto the north sea plateau during early phases of the lgm when the ncis started to operate this ice supply to the north sea was cut off and the fast flow of the ncis also led to a lowering of the ice surface along the norwegian channel and thereby drawdown of the entire ice sheet this facilitated rapid calving of the ice front in the north sea and we reconstruct a large open bay across the entire northern north sea by 20 ka based on our 10 be ages in the