comparison of geodetic and glaciological mass balance techniques gulkana glacier alaska u s a the net mass balance on gulkana glacier alaska u s a has been measured since 1966 by the glaciological method in which seasonal balances are measured at three index sites and extrapolated over large areas of the glacier systematic errors can accumulate linearly with time in this method therefore the geodetic balance in which errors are less time dependent was calculated for comparison with the glaciological method digital elevation models of the glacier in 1974 1993 and 1999 were prepared using aerial photographs and geodetic balances were computed giving 6 0 0 7 m w e from 1974 to 1993 and 11 8 0 7 m w e from 1974 to 1999 these balances are compared with the glaciological balances over the same intervals which were 5 8 0 9 and 11 2 1 0 m w e respectively both balances show that the thinning rate tripled in the 1990s these cumulative balances differ by 6 for this close agreement the glaciologically measured mass balance of gulkana glacier must be largely free of systematic errors and be based on a time variable area altitude distribution and the photography used in the geodetic method must have enough contrast to enable accurate photogrammetry

the susceptibility of uk groundwaters to acidic deposition the weathering of minerals at shallow depths provides much of the sink for acidic atmospheric deposition the geology of the uk has been divided into four classes according to the extent to which the bedrock is likely to provide buffering and possibly give rise to acidic surface or groundwaters other modifying factors including soils superficial deposits and land use are also considered the likely sources and sinks of h in shallow groundwater systems are also reviewed most available groundwater data are derived from major aquifers often in carbonate bearing lithologies which afford excellent buffering and which are unlikely ever to be adversely affected by acidic deposition relatively few data exist for shallow groundwaters widely used for domestic supplies in rural areas especially in western and northern britain where groundwaters might be most affected acidic groundwaters and or surface waters are defined on the basis of their alkalinity and calcite saturation index si c acidic groundwaters are most likely to occur where 1 acid soils are found and glacial drift is thin or absent 2 the source of acidic inputs is high 3 carbonate minerals are absent 4 the residence time of water is short low alkalinity groundwater is found in many sandstone lithologies including the sherwood sandstone a major uk aquifer many lower palaeozoic strata and granites however existing data for susceptible areas are insufficient to show whether or not there have been significant long term changes in groundwater acidity or alkalinity

groundwater chemistry of al under dutch sandy soils effects of land use and depth aluminium has received great attention in the second half of the 20th century mainly in the context of the acid rain problem mostly in forest soils in this research the effect of land use and depth of the groundwater on al ph and doc concentration in groundwater under dutch sandy soils has been studied both ph and doc concentration play a major role in the speciation of al in solution furthermore the equilibrium with mineral phases like gibbsite amorphous al oh 3 and imogolite has been considered agricultural and natural land use were expected to have different effects on the ph and doc concentration which in turn could influence the total al concentration and the speciation of al in groundwater at different depths phreatic shallow and deep an extensive dataset n 2181 from the national and some provincial monitoring networks on soil and groundwater quality was used land use type and groundwater depth did influence the ph and al and doc concentrations in groundwater samples the al concentration ranged from 7 to 1941 mol l 1 at ph 4 highest al concentrations were found for natural phreatic groundwater the doc concentration decreased and the median ph increased with depth of the groundwater natural phreatic groundwater showed lower ph than the agricultural phreatic groundwater highest doc concentrations were found for the agricultural phreatic groundwater induced by the application of organic fertilizers besides inorganic complexation the nica donnan model was used to calculate al3 concentrations for complexation with doc below ph 4 5 groundwater samples were mainly in disequilibrium with a mineral phase this disequilibrium is considered to be the result of kinetic constraints or equilibrium with organic matter log k values were derived by linear regression and were close to theoretical values for al oh 3 minerals e g gibbsite or amorphous al oh 3 except for natural phreatic groundwater for which lower log k values were found complexation of al with doc is shown to be an important factor for the al concentrations especially at high doc concentrations as was found for agricultural phreatic groundwater 2007 elsevier ltd all rights reserved

the mass balance of circum arctic glaciers and recent climate change the sum of winter accumulation and summer losses of mass from glaciers and ice sheets net surface mass balance varies with changing climate in the arctic glaciers and ice caps excluding the greenland ice sheet cover about 275 000 km2of both the widely glacierized archipelagos of the canadian norwegian and russian high arctic and the area north of about 60 n in alaska iceland and scandinavia since the 1940s surface mass balance time series of varying length have been acquired from more than 40 arctic ice caps and glaciers most arctic glaciers have experienced predominantly negative net surface mass balance over the past few decades there is no uniform recent trend in mass balance for the entire arctic although some regional trends occur examples are the increasingly negative mass balances for northern alaska due to higher summer temperatures and increasingly positive mass balances for maritime scandinavia and iceland due to increased winter precipitation the negative mass balance of most arctic glaciers may be a response to a step like warming in the early twentieth century at the termination of the cold little ice age arctic ice masses outside greenland are at present contributing about 0 13 mm yr 1to global sea level rise

slight mass loss revealed by reanalyzing glacier mass balance observations on glaciar antisana 15α inner tropics during the 1995 2012 period in this paper we reanalyze the glacier mass balance on glaciar antisana 15 over the 1995 2012 period annual glacier mass balances were quantified on the basis of monthly glaciological measurements using an adaptation of lliboutry s statistical approach the geodetic mass balance was computed between 1997 and 2009 giving a cumulative balance of 1 39 1 97 m w e and a slightly negative adjusted annual glaciological mass balance 0 12 0 16 m w e a 1 despite a careful analysis of uncertainties we found a large discrepancy between the cumulative glaciological and the geo detic mass balances over the common period of 4 66 m w e this discrepancy can mainly be explained by underestimated net accumulation in the glacier upper reaches which could be due to the peculiar climate conditions of the equatorial zone with year round accumulation thereby preventing clear identification of annual layers an increase of 70 in measured rates of net accumulation would be needed to balance the glaciological and geodetic mass balances a hypothesis confirmed by estimated ice flux in the vicinity of the ela consequently the vertical gradient of precipitation may be higher than previously estimated and the accumulation processes including the role of frost deposition need to be carefully analyzed

geochemical and sr isotopic characteristics of stream and spring waters from small forested catchments at seto central japan hydrogeochemical processes controlling surface water chemistry were examined in five small 90 wt suggest slow chemical weathering the dissolved solute concentrations are generally of similar magnitude in stream waters within the catchments of similar bedrock lithology the high inverse correlation r2 0 72 between ph and so4 concentrations and the high positive correlation r2 0 90 between ba and so4 concentrations in waters draining tokai conglomerate suggest that barite baso4 is being dissolved in an acidic environment the three catchments were identified as being sensitive to acidic deposition because the bedrock conglomerate provided little capacity to buffer acidic inputs the soils from the granite area have a high cation exchange capacity cec an average of 868 mol kg and are nearly ten times greater than the soils from the conglomerate area because ion exchange besides weathering is the main source that counteracts soil acidification the sensitivity to further acidification may increase

spatial variability in the flow of a valley glacier deformation of a large array of boreholes measurements of the deformation of a dense array of boreholes in worthington glacier alaska show that the glacier moves with generally bed parallel motion strain in the 200 m deep valley glacier is constant near the surface but follows a nonlinear vertical profile below a depth of about 120 m by a depth of 180 m the octahedral strain rate reaches 0 35 yr 1 the three dimensional velocity field shows spatial complexity with significant deviations from plane strain despite relatively simple valley geometry in the vicinity of the 6 10 6 m 3 study volume no evidence was found for time varying deformation or movement along localized shear planes observations were made by repeatedly measuring the long axis geometry of 31 closely spaced boreholes over a 70 day period and three additional holes after 1 full year of deformation the holes were spaced 15 to 30 m apart installation and measurement of such a large number of boreholes required the development of a semiautomated hot water drilling system that creates straight and vertical boreholes with uniform walls the equipment and procedures enables borehole profiles to be measured without the use of hole casing inclinometry measurements collected in the holes were processed analyzed for error and visualized as a fully three dimensional data set the new methods offer unique insight into small scale spatial and temporal variations in the pattern of flow in a valley glacier

spatial patterns of glaciers in response to spatial patterns in regional climate abstract glaciers are direct recorders of climate history and have come to be regarded as emblematic of climate change they respond to variations in both accumulation and ablation which can have separate atmospheric controls leading to some ambiguity in interpreting the causes of glacier changes both climate change and climate variability have characteristic spatial patterns and time scales the focus of this study is the regional scale response of glaciers to natural patterns of climate variability using the pacific northwest of north america as the setting the authors employ a simple linear glacier model to study how the combination of patterns of melt season temperature and patterns of annual accumulation produce patterns of glacier length variations regional scale spatial correlations in glacier length variations reflect three factors the spatial correlations in precipitation and melt season temperature the geometry of a glacier and how it determines the relative importance of temperature and

acidification of shallow groundwater in the unconfined sandy aquifer of the city of douala cameroon western africa implications for groundwater quality and use the alluvial aquifer underlying the city of douala comprises shallow quaternary deposits where groundwater is the main source for domestic and drinking purposes shallow groundwater in the area show signs of acidification with average ph range of 3 8 6 8 long term groundwater chemistry data 1998 2013 hydrogeochemical and r mode factor analysis were used to establish the acidification process of shallow groundwater and also determine possible origin and implications for water quality and use in the area twenty six groundwater sample points three streams and three rain sample points were studied seasonally in the 2006 2008 and the 2010 2013 study periods the data were compared with result of a study 7 years earlier 1998 1999 the results show evidence of acidification manifested by depletion of hco3 a decrease in the ph and increase in so4 and no3 concentrations of shallow groundwater average groundwater ph range is 3 94 7 70 1998 1999 3 8 6 91 2006 2008 and 3 7 6 8 2010 2013 only approximately 16 1998 1999 14 2006 2008 and 11 11 2010 2013 of water samples fall within the range of ph 6 5 8 5 for potable water according to who 1993 the alkalinity acid neutralizing capacity of the shallow groundwater has decreased significantly coupled with increase in the number of zero alkalinities recorded in the 2010 2013 the shallow groundwater is generally undersaturated with common carbonate minerals calcite dolomite therefore providing insufficient acid buffer principal component analysis in combination with hydrogeochemical studies revealed that four main factors are responsible for the groundwater chemistry and acidity 1 acid atmospheric deposition 2 anthropogenic activities industrial effluent discharges and acid spill 3 chemical weathering and 4 coastal atmospheric deposition cation exchange in general the shallow groundwater is not suitable for drinking and domestic purposes with respect to the low ph and elevated nitrate concentration in view of the implications such as increase in corrosion and increased mobilization of toxic elements e g al pb cu zn mn as well as their possible harmful effect on health it is recommended that the causes rate of acidification and the mobility of trace elements be investigated with more details

the distribution and origins of extremely acidic saline groundwaters in the south of western australia groundwater and digital mapping datasets provide new insights abstract some of the largest extents of naturally occurring acidic waters are found across southern australia the origins of these systems remain poorly understood with many hypotheses for their genesis australian government agency groundwater datasets and mapping data vegetation geology regolith and soils for south western australia unavailable to previous researchers were statistically analysed to better understand the origins of acidic groundwater and guide additional fieldwork to study the origins of acidic saline groundwater the groundwater data showed a distinct bimodal distribution in ph the acid population had a median ph of 3 5 and the larger non acid population had a median ph of 6 6 acidic groundwater became progressively more common further from the coast towards the drier internally drained regions acidic groundwater was mostly confined to the lower slopes and valley floors with localised controls on distribution paradoxically subsoil alkalinity within the internally drained inland regions had the strongest correlation with acidic groundwater r2 0 85 vegetation was also a strong predictor of acidic groundwater acidic groundwater had the highest occurrence under eucalyptus woodlands and shrublands that grew on alkaline calcareous soils pre clearing soil data in areas with acidic saline groundwater showed that the upper 1 m of the unsaturated zone had a ph around 8 while the ph at depths greater than 5 m decreased to 1 5 m there the iron is reduced around roots and the alkalinity generated by microbial iron reduction is removed by biogenic calcification processes the iron moves in solution further down the profile following roots where it comes in contact with the oxygenated unsaturated zone matrix and is oxidised generating acid the resulting acidic recharging solution acidifies the unsaturated zone matrix saline groundwater moving through the matrix becomes acidified due to ion exchange or direct recharge the main chemical processes were modelled in phreeqc to test the plausibility of the hypothesis and acidic solutions with a ph of 3 8 or lower were obtained

acidification buffering and salt effects in the unsaturated zone of a sandy aquifer klosterhede denmark acidification of groundwater in a noncalcareous sandy aquifer at klosterhede denmark is the result of acid rain deposition in the 4 to 5 m thick unsaturated zone the ph ranges from 4 2 to 4 9 with al concentrations of up to 0 8 mmol l sup minus 1 the groundwater at the top of the saturated zone still has a ph below 5 deposition of sea salt affects the solute profiles and its importance varies both spatially from the forest margin to the inner part of the forest and temporally through seasonal variations in infiltration and dry deposition as a result pulses of high solute concentrations travel downward through the unsaturated zone the cation exchange capacity cec of the sediments ranges between 0 2 and 1 meq 100 g sup minus 1 and in the acidified zone base saturation is around 17 the pore waters are close to equilibrium with gibbsite supersaturated for kaolinite and strongly undersaturated for other silicate minerals mass balance calculations on increases in dissolved silica over depth suggest that the buffering effect of silicate weathering is small buffering processes and solute transport were modeled with the code phreeqm simulation of pre acid rain weathering indicates that this process operates on a timescale of thousands of years more yielding minimum ph values near 5 2 and a base saturation of greater than 70 the present leaching of al sup 3 rich acid water from the soil yields acidification rates of 7 and 10 cm yr sup minus 1 for weathering of a naturally weathered and a pristine profile respectively simulation of infiltration of sea salt pulses indicates that the cation distribution quickly becomes attenuated by the exchanger composition however due to coupling of gibbsite equilibrium with ion exchange processes downward traveling pulses with high solute concentrations will cause ph variations throughout the unsaturated zone by precipitation and dissolution of gibbsite 67 refs 16 figs 3 tabs less

structure morphology and water flux of a subglacial drainage system midtdalsbreen norway digital elevation models of the surface and bed of midtdalsbreen norway are used to calculate subglacial hydraulic potential and infer drainage system structure for a series of subglacial water pressure assumptions ranging from atmospheric to ice overburden a distributed degree day model is used to calculate the spatial distribution of melt on the glacier surface throughout a typical summer which is accumulated along the various drainage system structures to calculate water fluxes beneath the glacier and exiting the portals for the different water pressure assumptions in addition 78 dye tracing tests were performed from 33 injection sites and numerous measurements of water discharge were made on the main proglacial streams over several summer melt seasons comparison of the calculated drainage system structures and water fluxes with dye tracing results and measured proglacial stream discharges suggests that the temporally and spatially averaged steady state water pressures beneath the glacier are 70 of ice overburden analysis of the dye return curves together with the calculated subglacial water fluxes shows that the main drainage network on the eastern half of the glacier consists of a hydraulically efficient system of broad low channels average width height ratio 75 the smaller drainage network on the west consists of a hydraulically inefficient distributed system dominated by channels that are exceptionally broad and very low average width height ratio 350 the even smaller central drainage network also consists of a hydraulically inefficient distributed system dominated by channels that are very broad and exceptionally low average width height ratio 450 the channels beneath the western and central glacier must be so broad and low that they can essentially be thought of as a linked cavity system

acid groundwater in an anoxic aquifer reactive transport modelling of buffering processes abstract the acidification of groundwater due to acid rain was investigated in a quaternary sandy aquifer in the fuhrberger feld near hannover germany the groundwater recharged through an area covered by a coniferous forest had a ph in the range 4 5 down to a depth of 5 m the evolution in groundwater chemistry along the flow path was investigated in a transect of multisamplers a 2d groundwater flow model was established delineating the groundwater flow field and a groundwater flow velocity of around 80 m a along the flow path was derived speciation calculations showed the groundwater to be close to equilibrium with the mineral jurbanite alohso4 over the ph range 4 0 6 5 this suggests an accumulation of acid rain derived so 4 2 in the aquifer sediment during the decades with high atmospheric s deposition the groundwater has a ph of around 4 5 in the upstream part of the flow path increasing to near 6 further downstream 1d reactive transport modelling using phreeqc was used to analyze different combinations of buffering processes the first model contains ion exchange in combination with jurbanite dissolution at the ion exchange front al3 is adsorbed leading to the dissolution of jurbanite and an increase in ph comparison with field data showed that the simulated increases in ph and alkalinity are much lower than observed in the field the second model includes organic matter degradation in addition to ion exchange and jurbanite dissolution the model included the reduction of so 4 2 and fe oxides as well as the precipitation of fe sulfide this model matches the field data well and illustrates the importance of redox processes for ph buffering in the fuhrberg aquifer the current progress of the acidification front is about 4 m a this corresponds to an average value of 150 a of acid input which covers large historical variations remediation is expected to take the same time span because it requires desorption and neutralization of adsorbed al3 from the aquifer sediment

processes controlling acid attenuation in the unsaturated zone of a triassic sandstone aquifer u k in the absence of carbonate minerals abstract continuous core samples were taken through the unsaturated zone at three sites on the outcrop of permo triassic sandstone in the british west midlands sample sites were chosen for lack of recent direct anthropogenic disturbance and for differing vegetation heathland birch woodland and conifer forest interstitial water was extracted and analyzed for 32 major and trace elements solid phases were analyzed for exchangeable cations and mineralogy the rate of recharge calculated using a cl mass balance method was three times greater below heathland than below afforested sites owing to higher evapotranspiration rates in the woodlands carbonate minerals were absent from the unsaturated zone at each site soil solutions were acidic and soils at the woodland sites were more acidic ph 4 0 than those at the heathland site ph 4 5 acidic interstitial water solutions were found to up to 5 0 m depth in the unsaturated zone and are partially neutralized by two aluminosilicate mineral reactions in the unsaturated zone cation exchange and k feldspar dissolution the rate at which these acid neutralizing reactions act to neutralize acidity is revealed by the rate of depletion of base cations from the unsaturated zone in recharge solutions k dissolution ca 2 mg 2 cation exchange the total base cation depletion rate was greatest below heathland this can be attributed mainly to the greater rate of so 4 assimilation by the woodland biome

changes in area and geodetic mass balance of small glaciers polar urals russia 1950 2008 changes in area of 30 small glaciers mostly 1 km2 in the northern polar urals 67 5 68 25 n between 1953 and 2000 were assessed using historic aerial photography from 1953 and 1960 aster and panchromatic landsat etm imagery from 2000 and data from 1981 and 2008 terrestrial surveys changes in volume and geodetic mass balance of igan and obruchev glaciers were calculated using data from terrestrial surveys in 1963 and 2008 in total glacier area declined by 22 3 3 9 in the 1953 60 2000 period the areas of individual glaciers decreased by 4 46 surfaces of obruchev and igan glaciers lowered by 22 5 1 7 m and 14 9 2 1 m over 45 years geodetic mass balances of obruchev and igan glaciers were 20 66 2 91 and 13 54 2 57 m w e respectively glacier shrinkage in the polar urals is related to a summer warming of 1 c between 1953 81 and 1981 2008 and its rates are consistent with other regions of northern asia but are higher than in scandinavia while glacier shrinkage intensified in the 1981 2000 period relative to 1953 81 increasing winter precipitation and shading effects slowed glacier wastage in 2000 08

climate at the equilibrium line of glaciers the relationships between temperature precipitation and radiation on glacier equilibrium lines are investigated using 70 glaciers for which the mass balance and meteorological observations have been carried out for sufficiently long periods it is found that the characteristic climate at glacier equilibrium lines can be described using the summer 3 months temperature in a free atmosphere annual total precipitation and the sum of global and long wave net radiation all of these are measured at or very near the equilibrium line altitudes then it is shown how the shift of the equilibriumline will occur as a result of a climatic change finally the effect of the shift of the equilibrium line on the annualmean specific mass balance is analytically derived and compared with observations the present results make it possible to identify the altitudes in climate models where glacierization should begin and to evaluate the mass balance changes as a result of possible future changes in the climate

the influence of parent material on small scale spatial changes in streamwater chemistry in scottish upland catchments abstract spatial changes in streamwater chemistry in seven upland catchments in ne scotland have been studied using samples collected at 250 m intervals from the stream source to the catchment outlet the catchments contain a number of different parent materials including granites and diorite from the lochnagar complex and metasediments and metabasites from the argyll and appin groups of the dalradian supergroup samples were collected under low flow conditions between june 1989 and january 1990 and ten component ions were determined this paper concentrates on ph ca mg na and k all seven catchments show major changes in stream solute concentrations along their length samples collected immediately downstream of the source typically show a rapid increase in ph with distance reflecting degassing in the stream of co 2 from the soil solution further down the catchment small scale spatial changes in streamwater chemistry appear to be strongly influenced by the underlying geology as the stream flows over parent materials with distinctly different geochemical characteristics the ph and ca and mg concentrations in the stream show rapid changes reflecting changes in the underlying lithology in a number of the catchments k also exhibits significant spatial variability along the length of the stream the underlying geology appears to have little effect on na concentrations which typically increase from the source to the bottom of the catchment these data suggest that small scale spatial changes in streamwater chemistry may provide a useful tool for identifying changes in the underlying geology in poorly exposed areas in addition they also have implications for regional critical load mapping and prediction of streamwater sensitivity to acidification

high resolution regional hydrogeochemical baseline mapping of stream water of wales the welsh borders and west midlands region abstract the stream water hydrogeochemical database produced by the geochemical baseline survey gbase of the british geological survey has recently been enhanced in the light of experimental pilot studies in north wales to meet a wider range of economic and environmental objectives which require modern integrated and strategic geochemical surveys for their implementation hydrogeochemical data are therefore now collected in conjunction with geochemical data for stream sediments soil samples and mineral concentrates the density of sampling based on the collection of stream water at near baseflow conditions during the late summer period each year has been increased to one site per 1 75 km 2 and a broader spectrum of geochemical determinants introduced provisional regional datasets are being prepared for an extensive region covering wales the welsh borders and part of the west midlands representing over 17 000 sample sites bedrock geology and base metal sulphide mineralisation are particularly well reflected in the stream water chemistry at the regional scale the influence of secondary factors such as geomorphology atmospheric controls and anthropogenic contamination due to agriculture urban industrial and military developments can also be readily distinguished the data obtained by systematic high resolution sampling of first and second order streams vary in concentration over three or four orders of magnitude for many of the analytes studied here this compares with a range of only one or two orders of magnitude for many of the analytes in stream sediment samples the extended range in values for stream water is an important factor in the gridding plotting and production of relatively stable maps they are relatively unaffected either by short temporal changes in stream water flow which are attributable either to storm events noted during the sampling campaign or by annual differences between wet and dry summers in different years this has enabled a series of robust surface hydrogeochemical maps to be prepared for analytical data collected during the summer sampling campaigns conducted annually from 1989 to 1994 these maps provide a unique source of synoptic baseline information for a wide range of economic and environmental applications especially when combined with other geoscience datasets in a gis environment

elevation volume and terminus changes of nine glaciers in north america nine glaciers in alaska and washington u s a originally mapped as part of the international geophysical year igy in 1957 58 were re mapped between 1993 and 1996 eight using airborne surface elevation profiling and the ninth using ground based kinematic global positioning system methods elevation volume and terminus changes were determined for the approximately 38 year period between the igy mapping and the profiling all nine glaciers showed substantial thinning at lower elevations seven of the nine thickened at higher elevations none of the glaciers had a significant net volume increase two had close to zero change and the others had a decrease for the eight glaciers for which we could obtain quantitative information the mean thickness change was 10 m with a large scatter 8 m standard deviation the volume and terminus changes had no clear geographic pattern and no simple relationship between volume change and terminus advance or retreat was identified the largest error in the estimated volume changes is due to map errors

towards more detailed methods for quantifying the acid susceptibility of rocks and soils the sensitivity of rocks and soils to acidification is best described by their acid base titration curves these curves tend to be relatively featureless but can be usefully summarized in terms of their initial ph the buffer capacity at this ph and the total acidity to ph 8 3 unfortunately the shapes of soil titration curves depend on the type and concentration of background electrolyte and the rate of titration therefore while a set of standard titration conditions can be defined the resulting titration curves will not simulate those applicable to in situ field conditions as required for modelling purposes to progress it is necessary to gain a better understanding of the sources of and sinks for acidity in rocks and soils for soils partitioning of the acidity into soil solution neutral salt extractable and solid phase but not neutral salt extractable components provides a promising approach this is demonstrated using a series of soil samples derived from an extremely acid humus iron podzol overlying eocene sand near wokingham berks

hydrogeochemistry as an aid to geological interpretation the glen roy area scotland the hydrochemistry of first and second order streams sampled at a density of 1 km 2 has been used to investigate ways of enhancing information obtained during regional geological mapping the glen roy area of scotland is a pristine area with large variations in bedrock geology ranging from dalradian metasediments including carbonates to granite granodiorite and appinite rocks coarse grained lamprophyre but with relatively minor drift alkalinity hco 3 is used to determine the extent of water rock interaction with both silicate and carbonate rocks the ratio na cl is also used to measure the extent of silicate reaction dolomitic facies are picked out in areas with carbonate by mg mn fe and y are useful indicators of the weathering of biotite and garnet a strong and well defined hydrogeochemical anomaly of ba sr and k outline the outcrops of the appinites together with hco 3 these three elements define an extended nw se lineament strath ossian lineament which includes possible concealed areas of appinite the bicarbonate probably reflecting the presence of a carbonate aureole derived from mantle co 2 in particular the bedrock characteristics in poorly exposed ground can be inferred and information obtained on the volume of bedrock through which the water has passed

updated estimates of glacier volume changes in the western chugach mountains alaska and a comparison of regional extrapolation methods and 2001 2004 average net balance rates ranged between 3 1 to 0 16 m yr 1 for the tidewater and 1 5 to 0 02 m yr 1 for the nontidewater glaciers we tested several methods for extrapolating these measurements to all the glaciers of the western chugach mountains using a process similar to cross validation predictions of individual glacier changes appear to be difficult probably because of the effects of glacier dynamics which on long multidecadal timescales complicates the response of glaciers to climate in contrast estimates of regional contributions to rising sea level were similar for different methods mainly because the large glaciers whose changes dominated the regional total were among those measured for instance the above sea level net balance rate of columbia glacier 3 1 0 08 km 3 yr 1 water equivalent weq or an equivalent rise in sea level sle of 0 0090 0 0002 mm yr 1 was nearly half of the total regional net balance rate of the western chugach mountain glaciers 7 4 1 1 km 3 yr 1 weq or 0 020 0 003 mm yr 1 sle between 1950 1957 and 2001 2004 columbia glacier is a rapidly retreating tidewater glacier that has lost mass through processes largely independent of climate tidewater glaciers should therefore be treated separately when performing regional extrapolations

hydrochemical evolution of the east midlands triassic sandstone aquifer england a detailed hydrogeochemical interpretation has been made of the red bed sherwood sandstone triassic aquifer of the east midlands of england on which a radiocarbon model has been used to establish a chronology of groundwaters along the flow line groundwater evolution is dominated by carbonate and sulphate mineral solution and precipitation and by redox reactions cation exchange reactions are negligible and the hydrogeochemistry has evolved in the absence of residual saline water three distinct zones are recognised 1 i recent groundwater mainly 100 y oxidising dominated by congruent dissolution of dolomite and by inputs from atmospheric and anthropogenic sources 2 ii groundwater age 103 104 y predominantly reducing dominated by incongruent dissolution of dolomite 3 iii groundwater age 104 y reducing conditions approach to isotopic and chemical equilibrium in the carbonate system dominance of gypsum dissolution the minor and trace element variation can be interpreted in relation to the principal geochemical reactions and recharge history na cl f and b are controlled by atmospheric inputs sr2 and mn2 trends can be explained by carbonate and sulphate mineral dissolution ba2 is derived from carbonates but controlled by barite equilibrium fe so42 no3 and u are strongly influenced by redox reactions the concentrations of transition metals and other elements remain very low only li and k are considered to represent additions by reaction of silicate minerals the extent of direct anthropogenic influence is probably limited to enhanced so4 no32 and possibly cu zn and pb in zone i

beryllium in river baseflow shallow groundwaters and major aquifers of the u k abstract beryllium is potentially a highly toxic element which may be mobilised especially under acidic conditions in natural waters results from major aquifers the unsaturated zone from shallow groundwaters and river baseflow were used to establish the naturally occurring baseline concentrations in u k waters out of 924 samples from 13 aquifer units be was detected in only 12 samples in carbonate aquifers no be was found above the detection limit of 0 05 g l the occurrence of be 0 05 g l was restricted to arenaceous aquifers where concentrations up to 1 g l be were found mainly in the carboniferous millstone grit and lower cretaceous lower greensand aquifers interstitial water profiles from the unsaturated zones of the lower greensand surrey and triassic sandstone west midlands contain be concentrations in excess of 10 g l within the top 10 m which may persist to the water table at concentrations near to 1 g l be the only major anomaly to be found in river baseflow was from the mourne mountains of northern ireland where be concentrations of up to 4 7 g l were found associated with the outcrop of the tertiary granite intrusion elsewhere be 0 22 g l was found in neutral groundwaters derived from granite feeding the acid loch fleet southern scotland in which concentrations of 0 09 g l were maintained beryllium occurrence therefore depends strongly on geology the predominant aqueous species below ph 5 5 is be 2 and above this be oh dominates the presence of high al in most waters sampled greatly suppresses the formation of bef complex ions beryllium shows close geochemical behaviour with mg across a range of ph which may have environmental consequences if be substitution for mg takes place

an optimized method to calculate the geodetic mass balance of mountain glaciers understanding the effects of climate on glaciers requires precise estimates of ice volume change over several decades this is achieved by the geodetic mass balance computed by two means 1 the digital elevation model dem comparison seqdem allows measurements over the entire glacier however the low contrast over glacierized areas is an issue for the dem generation through the photogrammetric techniques and 2 the profiling method sepm is a faster alternative but fails to capture the spatial variability of elevation changes we present a new framework ssd that relies upon the spatial variability of the elevation change to densify a sampling network to optimize the surface elevation change quantification our method was tested in two small glaciers over different periods we conclude that the sepm overestimates the elevation change by 20 with a mean difference of 1 00 m root mean square error rmse 3 00 m compared with results from the seqdem method a variogram analysis of the elevation changes showed a mean difference of

major minor and trace element mobility in the acidic upland forested catchment of the upper river severn mid wales variations in the major minor and trace element concentrations in two streams within a coniferous forest are described and are related to hydrological and hydrogeochemical factors the rainfall chemistry reflects a maritime influence although there are occasional pollutant inputs ph 4 5 streamwater chemistry variations are strongly dependent upon flow baseflow chemistry determined by reactions in the inorganic soils and bedrock is of a mg ca hco 3 type ph 6 7 5 mineralization yields up to a four fold increase in ca hco 3 zn and so 4 concentrations ph 0 5 units higher stormflow chemistry reflects hydrogeochemical processes in the organic soil horizons the stormflow waters are acidic ph 4 5 and are enriched by an order of magnitude in h ai y co and mn mineral equilibrium calculations have been applied to aluminium hydroxides crystalline and amorphous aluminosilicates and hydroxy aluminium sulphates to determine the degrees of mineral saturation in the streamwaters ion exchange reactions have been evaluated to describe the consequences of natural variations in atmospheric salt loadings and evapotranspiration on the stream water chemistry and to explain low na cl ratios in storm waters

time scale for adjustment of glaciers to changes in mass balance the length of time tm over which a glacier responds to a prior change in climate is investigated with reference to the linearized theory of kinematic waves and to results from numerical models we show the following tm may in general be estimated by a volume time scale describing the time required for a step change in mass balance to supply the volume difference between the initial and final steady states the factor f in the classical estimate of m l u where i is glacier length and u is terminus velocity has a simple geometrical interpretation ft is the ratio of thickness change averaged over the full length i to the change at the terminus although both u and f relate to dynamic processes local to the terminus zone the ratio f u and therefore tm are insensitive to details of the terminus dynamics in contrast to conclusions derived from some simplified kinematic wave models a more robust estimate of tm independent of terminus dynamics is given by tm h b where h is a thickness scale for the glacier and b is the mass balance rate negative at the terminus we suggest that tm for mountain glaciers can be substantially less than the 1o2 103 years commonly considered to be theoretically expected