multi proxy holocene palaeoclimate records from walton moss northern england and dosenmoor northern germany assessed using three statistical approaches abstract plant macrofossil analysis is a robust and established method for estimating palaeoclimatic changes from raised peat bogs there remains uncertainty however over the best statistical method to use for converting the palaeoecological data to an index of bog surface wetness bsw to test this a 9 m core wlm22 from walton moss northern england was analysed for changes in plant macrofossils testate amoebae and humification the plant macrofossil data were then converted to a single curve of bog surface wetness bsw using three different techniques weighted averaging by the dupont hydroclimatic index dhi and ordination by detrended correspondence analysis dca and by non metric multidimensional scaling nmds through comparison with testate amoebae and humification data from the same core it was observed that a statistically better fit was found with the wetness curve from dhi than that from either ordination it is suggested that the weighted averaging method of dhi can provide a good indicator of bsw variation in long peat records where the profile incorporates data from both sphagnum dominated and eriophorum ericaceous dominated bog deposits which is common to nw european bogs the data also imply that with sufficient diversity of taxa there is potential for the further development of plant macrofossil transfer functions application of dhi to an additional data set from dosenmoor northern germany and comparison with published records from nw europe revealed coherent regional climatic variations

testing the timing of radiocarbon dated events between proxy archives for interpreting past changes on a regional or global scale the timings of proxy inferred events are usually aligned with data from other locations however too often chronological uncertainties are ignored in proxy diagrams and multisite comparisons making it possible for researchers to fall into the trap of sucking separate events into one illusionary event or vice versa here we largely solve this suck in and smear syndrome for radiocarbon 14 c dated sequences in a bayesian framework millions of plausible age models are constructed to quantify the chronological uncertainties within and between proxy archives we test the technique on replicated high resolution 14 c dated peat cores deposited during the little ice age c ad 14001900 a period characterized by abrupt climate changes and severe 14 c calibration problems owing to internal variability in proxy data and uncertainties in age models these and possibly many more archives are not consistent in recording decadal climate change through explicit statistical tests of palaeoenvironmental hypotheses we can move forward to systematic interpretations of proxy data however chronological uncertainties of non annually resolved palaeoclimate records are too large for answering decadal timescale questions

holocene carbon accumulation rates from three ombrotrophic peatlands in boreal quebec canada impact of climate driven ecohydrological change understanding the processes controlling peatland carbon c sequestration is critical to anticipate potential changes in the global c cycle in response to climate change although identification of these factors may be relatively straightforward on seasonal timescales at centennial to millennial timescales complexities arise because of interactions between climate vegetation hydrology and long term ecological processes to better understand the factors controlling long term c accumulation holocene rates of c sequestration were quantified from three pristine ombrotrophic peatlands in boreal quebec northeastern canada 52 n 75 76 w bulk density and loss on ignition analyses combined with radiocarbon dating and age depth modelling were used to estimate long term apparent rates of carbon accumulation past changes in vegetation and water table depth were obtained from plant macrofossil and testate amoeba analysis earliest regional peat accumulation started 7520 cal bp with long term rates of c s

palaeohydrology fires and vegetation succession in the southern baltic during the last 7500 years reconstructed from a raised bog based on multi proxy data we present the first 7500 yr long multi proxy record from a raised bog located at the southern baltic coast poland testate amoebae plant macrofossils pollen and microscopic charcoal were used to reconstruct environmental changes in pomerania northern poland kaszuby lakeland from a 7 m thick peat archive of st zki bog dated 5500 bc ad 1250 we obtained a record of proxies representing different spatial scales regional vegetation changed simultaneously with local vegetation and testate amoebae showed a pattern of change similar to that of pollen and plant macrofossils on the basis of the combined proxies we distinguished three hydroclimatic stages moist conditions 5500 3450 bc drier conditions with regionally increased fires up to 600 bc and again moist conditions from 600 bc onward during the drier interval a first climatic shift to wetter conditions at 1700 bc is indicated by regional pollen as the replacement of corylus by carpinus and locally by e g the increase of hyalosphenia elegans and mire plants such as sphagnum sec cuspidata furthermore we observed a correlation since 600 bc among the re expansion of carpinus after a sudden decline ca 950 bc increased peat accumulation increase of hyalosphenia species and fewer fires suggesting lower evapotranspiration and a stable high water table in the bog fagus started to expand after ad 810 gradually replacing carpinus which was possibly due to a gradually more oceanic climate though we cannot exclude human impact on the forests peat accumulation determined by radiocarbon dating varied with bog surface wetness the hydroclimatic phases found in st zki peatland are similar to moisture changes recorded in other sites from poland and europe this is the first detailed record of hydroclimatic change during the holocene in the southern baltic region so it forms a reference site for further studies on other southern baltic bogs that are in progress

controls on pit lake water quality at sixteen open pit mines in nevada thirty five mines in nevada currently have or will likely have a pit lake the large bulk mineable deposits in nevada mined below the water table are of several types including carlin type au quartz adularia precious metal quartz alunite precious metal and porphyry cu mo deposits of the 16 past or existing pit lakes at 12 different nevada mines most had near neutral ph and low metal concentrations yet most had at least one constituent e g so4 which exceeded drinking water standards for at least one sampling event water quality data indicate that in general poor water quality will not develop in carlin type au deposits wall rocks in the geologic environment typical of these deposits and in the specific pits sampled contain substantial amounts of carbonate which buffers the ph at slightly basic conditions and thereby limits the solubility of most metals similarly the quartz adularia precious metal deposits generally have geologic conditions that buffer ph and naturally prevent the development of poor water quality in both of these deposit types certain elements such as as and se that are mobile in neutral to basic waters may accumulate to levels near or exceeding drinking water standards pit lakes forming in quartz alunite precious metal deposits hosted in volcanic rocks or in porphyry cu mo deposits in plutonic rocks are of greatest environmental concern in nevada as both deposit types have relatively high acid generating potential and low buffering capacity however the sampled nevada pits in these deposit types indicate that the water may not be of poor quality in addition water quality in some pits may actually improve with time due to the increased water rock ratio as the pit fills with water as suggested by pit waters at one mine in a carlin type deposit getchell that improved between 1968 and 1982 although water quality in pits in each deposit type is generally good local site specific conditions e g surface water inflow and variations e g evaporation rates result in some pit lakes e g boss in the quartz adularia deposit type being of substantially poorer water quality than other lakes e g tuscarora in the same deposit type despite underlying geologic controls based on deposit type site specific variations in hydrogeologic conditions and surface geologic features can result in differing water quality in pit lakes in the same deposit types and these factors may in some cases provide an overriding control on the geochemical evolution of specific pit lakes

mobilization and speciation of arsenic from hydrothermally altered rock containing calcite and pyrite under anoxic conditions abstract the effects of water residence time and anoxic conditions on the mobilization and speciation of as in a calcite and pyrite bearing altered rock excavated during a road tunnel project has been evaluated using batch and column laboratory experiments higher infiltration rates i e shorter water residence times enhanced the leaching of as due to the higher ph values of the effluents and more rapid transport of dissolved as through the columns the concentration of as in the effluent also increased under anoxic conditions regardless of the water residence time this enhanced leaching of as under anoxic conditions could be attributed to a significant ph increase and decreased fe oxyhydroxide oxide precipitation compared to similar experiments done under ambient conditions processes that controlled the evolution of ph and the temporal release mechanisms of as under anoxic conditions were identical to those previously observed under ambient conditions the dissolution of soluble phases pyrite oxidation co precipitation and or adsorption desorption reactions speciation of as in the column experiments could partly be attributed to the ph dependent adsorption of as species onto fe oxyhydroxide oxide precipitates moreover apparent equilibrium of the total as and as iii concentrations was delayed under anoxic conditions in both batch and column experiments

a meta database of peatland palaeoecology in great britain we present and appraise a large compilation of peatland palaeoecological research in great britain and discuss the value of these data for secondary analysis we identify 475 radiocarbon dated palaeoecological records from british peatlands published since 1970 peatland palaeoecological research has been widespread but with some clear spatial biases reflecting factors such as accessibility and the location and interests of active researchers we show that basic details such as stratigraphic descriptions site coordinates and full details of radiocarbon dates are omitted from publications with surprising frequency and note the large quantity of data that only ever appears in phd theses to allow papers to remain concise while presenting essential background information we propose a system of standardised meta data in online supplementary material the extensive body of palaeoecological data for british peatlands has been relatively unexploited the compilation we present will be a valuable aid in making better use of this data resource

multiproxy evidence of little ice age palaeoenvironmental changes in a peat bog from northern poland little ice age lia climatic deteriorations have been abundantly documented in various archives such as ice lake sediments and peat bog deposits palaeoecological analyses of peat samples have identified these climatic deteriorations using a range of techniques for example palynology plant macrofossils testate amoebae or carbon isotopic analyses the use of inorganic geochemistry and the reconstruction of dust fluxes has remained a challenge in tracing the nature of lia climatic changes although the idea of enhanced erosion conditions and storminess is commonly discussed the conditions for dust deposition in peatlands over europe during the lia are rarely favourable because the natural forest cover over europe was much more important than nowadays preventing dust deposition this intense forest canopy masks the deposition of dust in peatlands in northern poland near the baltic shore the slowin skie blota area was deforested around ad 1100 ie just before the lia and therefore constitutes a key area for the reconstruction of lia climatic change with the support of a well constrained chronology climatic fluctuations are recorded in an ombrotrophic bog using inorganic geochemistry plant macrofossils and carbon isotopic analyses the reconstruction of lia climatic changes is in good agreement with other records from poland and ne europe however a c 50 year discrepancy can be observed between various records this discrepancy is possibly due to progressive time dependent cooling gradient from north to south europe

stability and meromixis in a water filled mine pit a field experiment examined stability and stratification in a disused mine fit filled with 1 75 x lo7 m3 of water vertical profiles of conductivity and temperature indicated that due to substantial chemical stratification spring and autumn overturn did not penetrate to the base of the pit although parameterization indicated that double diffusion should be expected we found only circumstantial evidence of associated step structure the available data suggest that groundwater inflow created a warm salty pool of water at the base of the water column giving the appearance of a meromictic structure with a monimolimnion however this pool was noi a consistent feature suggesting both a variable inflow and significant diffusion rates from the temperature data estimates indicated that hypolimnetic vertical eddy diffusivity varied between 1 x 10e7 and 5 x lo m s l the observations identify short term relatively energetic internal wave events that may have a significant impact on this value the present study is useful in two ways first it shows how pit lakes form a natural laboratory fcr a range of processes and second it illustrates how these processes relate to diffusion paranieterization it is clear that reliable parameterization is vital for long term modeling required for prediction of water quality over decadal timescales with the closure of an open cut mining operation come the dual problems of rehabilitation of the mine pit and containment of deleterious material generated by the mine during its life in many cases the pit fills with water either naturally or through mine activities thus an artificial lake of moderate volume is created davis and ashenberg 1989 characterization of the transport processes within the water column is important for two reasons first the pit is likely to contain hazardous levels of dissolved metals and second if vertical transport rates are low then the pit may prove suitable as a storage location for hazardous material water filled mine pit lakes pit lakes have received consideration in the literature but with a biological or geochemical emphasis e g klapper and schultz 1995 crater lakes are the natural system most similar to these artificial water bodies martin 1985 macintyre and melack 1985 pit lakes are unique for several reasons they are often deep relative to natural lakes of similar surface area they have high surrounding walls that often generate a microclimate different to that outside the pit they typically have very thin sediment layers they may undergo substantial and rapid changes in water level and they are likely to contain significant concentrations of dissolved material the final point is important if the dissolved material is environmentally harmful or if it leads to meromixis with these departures from what might be associated with typical natural lakes

climate change records between the mid and late holocene in a peat bog from serra do xistral sw europe using plant macrofossils and peat humification analyses abstract to implement models of global change information from peripheral regions and concerning the distinction between global and local events is needed in this context we studied the occurrence of hydrological changes over the last 5300 years in the southern most european area of active blanket bogs the reconstruction of the bog surface wetness was performed on the basis of the analysis of plant macrofossils and peat humification to interpret these proxies the current botanical composition of the bog and the ecological behavior of the different plant species were used from its present ecological behavior we have established the main indicator species for different bog surface wetness the seeds of juncus bulbosus and drosera rotundifolia which were significantly correlated with the humification index as well as the seeds and rhizomes of eriophorum angustifolium were the primary indicators for wetness the sphagnum species are not abundant and most are restricted to wet and damp periods the concordance between both proxies in spite of certain discrepancies allowed us to estimate the chronological sequence of hydrological changes along the bog profile we have differentiated 10 wet periods during which the bog surface could be flooded or wet 5300 4850 4350 3900 3550 3350 3150 3050 2700 2450 2250 2150 1950 1300 1150 1050 900 800 and 700 20 cal yr bp these identified wet periods are in agreement with previous paleoclimate studies with different spatial scales and proxies

radiocarbon dating of a recent high latitude peat profile stor amyrân northern sweden the value of both high precision hp and ams 14c determinations in the fine resolution dating of recent peat at stor amyr n near umea northern sweden has been explored a detailed chronology of accumu lation based on 14c an occurrence of the askja ad 1875 tephra and 241am measurements has been derived for the last 700 years this shows significant changes in the mass balance of the peat profile with minimum rates of net carbon sequestration overlapping with the period of minimum spring and summer temperature documented by published tree ring evidence the paper presents a methodology for calculating empirically past changes in the rate of net carbon sequestration in boreal peatlands and for exploring the effects of climatic variations and possible future global warming on these rates

decline and localized extinction of a major raised bog species across the british isles evidence for associated land use intensification the decline of s austinii sull ex aust formerly s imbricatum hornsch ex russ ssp austinii sull abstract the decline of s austinii sull represents one of the most striking vegetation russ ssp on the raised ex aust in most cases to local extinction represents one of the most striking vegetation changes on the raised bogs of britain and northwest europe during the last 2000 years this study uses plant macrofossil pollen and geochemical analyses to explore the record of human impact and land use intensification at the s austinii decline there is a clear temporal association between anthropogenic woodland clearance cereal cultivation soil erosion and contemporary climatic change with the decline of s austinii these findings suggest that s austinii is sensitive not only to rapid climate changes but also to the aerial deposition of soil dust and or accompanying pollutants a modern comparison of atmospherically derived nitrogen n loadings with the present presence absence of s austinii on 16 raised bogs shows that the species is only present where the loading lies below a critical threshold for n of 10 kg ha per yr the palaeoecological record also shows that s austinii has re established itself during phases of reduced human activity but in contemporary europe it is difficult to see this happening in the near future

the aqueous geochemistry of the berkeley pit butte montana u s a water levels in the berkeley pit butte montana are currently rising approximately 22m per year following the cessation of pumping in 1982 projections suggest that the pit may be filled to capacity at the 5520 ft 1682 m elevation by the year 2009 if remedial action is not implemented in addition as the water level in the pit continues to rise there is the potential for encroachment of contaminated water into the alluvial aquifer and subsequent transport of metals downgradient to silver bow creek geochemical measurements and aqueous samples collected during october 1987 indicate that water in the berkeley pit is moderately oxidizing eh 460mv below 30 m acidic ph 3 0 cafe sulfate solution the principal ions are al as ca cd cu fe k mg na so4 and zn which typically increase in concentration from the surface to the bottom of the pit arsenic occurs mainly as as v in total metal concentrations up to 1 mg l fe as fe iii in the top 3 m and as fe ii below this depth in concentrations up to 1000 mg l sulfate was measured in concentrations up to 6780 mg l from the deepest 130 m sample copper and zn were found in total metal concentrations of 202 and 512 mg l respectively at the 130 m sampling depth to verify the field eh measurements minteq was used to calculate a theoretical eh based on the fe ii fe iii couples the results suggest that the ratio fe ii fe iii is representative of the system eh when both species occur in measurable quantities 0 25mg l and when the minor species constitutes at least 5 of the total concentration data from this study were used in the geochemical computer code phreeqe to evaluate potential remediation of the water body through the addition of alkaline tailings fluid produced at the current milling operation on site five cases were evaluated two representative of conditions under ice cover pco2 not fixed and three open system simulations pco2 10 3 5 mineral controls included fe oh 3 gypsum caso4 2h2o jurbanite alohso4 and jarosite kfe3 so4 2 oh 6 the addition of three volumes of alkaline slurry to the existing volume of acidic fluid would raise the ph to 5 0 this option would take approximately 7 a at the current rate of production 11 6 million gallons per day 43 9 ml d at this time the fluid level would be approximately 20 m above the alluvial bedrock contact

solar forcing of climatic change during the mid holocene indications from raised bogs in the netherlands two cores of mid holocene raised bog deposits from the netherlands were 14 c wiggle match dated 14 c as a proxy for changes in solar activity is validated this paper adds to the increasing body of evidence that solar variability forced climatic changes during the holocene 14 c wiggle match dating mid holocene wet shifts

the acidic mine pit lakes of the iberian pyrite belt an approach to their physical limnology and hydrogeochemistry abstract this study examines some relevant limnological and hydrogeochemical characteristics of 22 mine pit lakes of the iberian pyrite belt ipb the studied pit lakes include some of the largest and historically most important mines of the ipb including corta atalaya and cerro colorado in riotinto filon norte filon centro and filon sur in tharsis aznalcollar or san telmo and many other of minor size as a whole these lakes constitute at present a large volume of highly acidic and metal polluted water some of these pit lakes are very recent e g corta atalaya 2 5 a los frailes 6 a and present a continuous hydrological and geochemical evolution although many others were abandoned decades ago and show nearly constant water volume depth profiles obtained in several pit lakes e g san telmo confesionarios cueva de la mora concepcion indicate that many of them have developed meromixis and show at present a permanent thermal and chemical stratification with a well defined chemocline separating an anoxic fe ii rich monimolimnion and a well mixed oxygenated and fe iii rich mixolimnion in the upper layer the bacterial oxidation of fe ii competes with photoreductive processes which take place in the surface water thus provoking diel cycles of fe ii concentration the observed water chemistry reflects the oxidation and dissolution of pyrite and other sulphides and gangue aluminosilicates from the country rock the pit lakes of the ipb cover a wide range of water compositions from circumneutral and relatively low metal e g los frailes ph 7 2 0 07 mg l fe 3 8 mg l mn 30 mg l zn to extremely acidic and metal loid rich e g corta atalaya ph 1 2 36 7 g l fe 6 7 g l zn 1 3 g l cu 159 mg l as most pit lakes however are comprised within the ph range of 2 2 3 6 and appear to be strongly buffered by the hydrolysis and precipitation of fe iii in the form of schwertmannite which forms colloids that can sorb trace elements from the aqueous phase

last millennium palaeoenvironmental changes from a baltic bog poland inferred from stable isotopes pollen plant macrofossils and testate amoebae the baltic coast of northern poland is a region of considerable potential interest for paleoclimatic studies because this region is under the influence of both oceanic and continental climates and that these two influences have likely changed through time also unlike many more intensively studied regions of europe human impact was more limited until the 19th century we present a multiproxy high resolution record from st zki mire an ombrotrophic mire located in northern poland 35 km from the baltic sea coast we combined four proxies from the peat testate amoebae stable isotopes 13c of sphagnum stems pollen and plant macrofossils supported by dendroecological data to assess the palaeoenvironmental changes that took place during the last millennium the general aim of this study was to test if a range of proxies testate amoebae pollen plant macrofossils and tree rings could allow inferring a climatic signal from a peat monolith despite the considerable anthropogenic impact on the pomerania landscape since the early medieval period combining internal e g macrofossils and testate amoebae and external pollen signals is key to distinguishing human from climatic signals in palaeoenvironmental studies of peatlands our more specific aims were to a reconstruct the last millennium palaeoenvironment in a baltic raised bog and its surroundings b identify the major wet dry shifts and correlate those events with climate change and human impact c assess the resilience of the baltic bog ecosystem following human impact we noted two disturbance periods in the history of the mire the two major disturbances in the history of the mire were dry periods i 1100 1500 ad and ii 1650 1900 2005 ad these are reflected in all indicators and can be interpreted as the mixture of climate impact and human activities however the pollen record shows little evidence of human indicators during the first dry shift the second disturbance can be related to local peat exploitation of the mire and then in the 20th century with limited artificial drainage from 1500 ad all proxies show that the water table abruptly rose in the mire the beginning of this shift occurred during the little ice age and therefore it is likely a climatic signal alternatively this wet shift could have been interpreted as a re wetting mire surface after peat burning but this interpretation is rejected because there is no evidence of major local fire in the macrofossil record the macrofossil data shows that sphagnum fuscum dominated the pristine mire vegetation but then declined and finally disappeared this pattern is comparable with the timing of extinction of sphagnum austinii in western europe this study illustrated the value of palynological analysis of peat archives especially for last millennium to assess the magnitude of anthropogenic land use changes for example the comparison of fagus beech and carpinus hornbeam history with the palaeohydrological record allowed us to exclude climate change as the most important factor for the decline and expansion of these tree species this study is the first direct comparison of testate amoeba and stable isotope data

forest dynamics and tip up pools drive pulses of high carbon accumulation rates in a tropical peat dome in borneo southeast asia singapore national research foundation singapore mit alliance for research and technology

a numerical approach to 14c wiggle match dating of organic deposits best fits and confidence intervals c 14 wiggle match dating wmd of peat deposits uses the non linear relationship between c 14 age and calendar age to match the shape of a sequence of closely spaced peat c 14 dates with the c 14 calibration curve a numerical approach to wmd enables the quantitative assessment of various possible wiggle match solutions and of calendar year confidence intervals for sequences of c 14 dates we assess the assumptions advantages and limitations of the method several case studies show that wmd results in more precise chronologies than when individual c 14 dates are calibrated wmd is most successful during periods with major excursions in the c 14 calibration curve e g in one case wmd could narrow down confidence intervals from 230 to 36 yr c 2003 elsevier science ltd all rights reserved

deciphering human climate interactions in an ombrotrophic peat record ree nd and pb isotope signatures of dust supplies over the last 2500 years misten bog belgium abstract a high resolution peat record from eastern belgium reveals the chronology of dust deposition for the last 2500 years ree and lithogenic elements in addition to nd and pb isotopes were measured in a 173 cm age dated peat profile and provide a continuous chronology of dust source and intensity calculated dust flux show pronounced increases c 300 bc 600 ad 1000 ad 1200 ad and from 1700 ad corresponding to local and regional human activities combined with climate change the industrial revolution samples 1700 1950 ad are characterised by a significant enrichment in sc normalised ree abundance sum ree sc 25 due to intensive coal combustion for the pre industrial revolution samples the sc normalised ree abundance 10

dating raised bogs new aspects of ams 14c wiggle matching a reservoir effect and climatic change abstract high resolution ams dating of holocene raised bog deposits engbertsdijksvenen the netherlands shows natural 14c variations wiggles which can be matched with the dendrochronological calibration curve comparison of our results with other conventionally dated peat cores and the 14c record shows an unexpected and as yet unreported reservoir effect and a marked and sudden wetting of the bog surfaces coinciding with the advent of a sporer type solar minimum the homeric minimum the potential of ams dating to vastly improve the accuracy of holocene chronologies is demonstrated

geochemical evolution of a high arsenic alkaline pit lake in the mother lode gold district california the harvard orebody at the jamestown gold mine located along the melones fault zone in the southern mother lode gold district california was mined in an open pit operation from 1987 to 1994 dewatering during mining produced a hydrologic cone of depression recovery toward the premining ground water configuration produced a monomictic pit lake with alkaline ca mg hco3 so4 type pit water concentrations of as up to 1 200 g l and total dissolved solids tds up to 2 000 mg l in this study pit wall rocks were mapped and chemically analyzed to provide a context for evaluating observed variability in the composition of the pit lake waters in relationship to seasonal weather patterns an integrated hydrogeochemical model of pit lake evolution based on observations of pit lake volume water composition samples collected between 1998 2000 2004 and processes occurring on pit walls was developed in three stages using the computer code phreeqc stage 1 takes account of seasonally variable water fluxes from precipitation evaporation springs and ground water as well as lake stratification and mixing processes stage 2 adds co2 fluxes and wall rock interactions and stage 3 assesses the predictive capability of the model two major geologic units in fault contact comprise the pit walls the hanging wall is composed of interlayered slate metavolcanic and metavolcaniclastic rocks and schists the footwall rocks are chlorite actinolite and talc tremolite schists generated by metasomatism of greenschist facies mafic and ultramafic igneous rocks alteration in the ore zone provides evidence for mineralizing fluids that introduced co2 s and k2o and redistributed sio2 arsenian pyrite associated with the alteration weathers to produce goethite and jarosite on pit walls and in joints as well as copiapite and hexahydrite efflorescences that accumulate on wall rock faces during dry california summers all of these pyrite weathering products incorporate arsenic at concentrations from 100 up to 1 200 ppm in the pit lake ph and tds reach seasonal highs in the summer epilimnion ph is lowest in the summer hypolimnion arsenic and bicarbonate covary in the hypolimnion rising as stratification proceeds and declining during winter rains the computational model suggests that water fluxes alone do not account for this seasonal variability loss of co2 to the atmosphere interaction with pit walls including washoff of efflorescent salts during the first flush and seasonal rainfall and arsenic sorption appear to contribute to the observed pit lake characteristics

fennoscandian summers from ad 500 temperature changes on short and long timescales quantitative estimates of 1480 years of summer temperatures in northern fennoscandia have previously been derived from continuous treering records from northern sweden here we show the results of spectral analyses of these data only a few peaks in the spectra are consistently significant when the data are analyzed over a number of sub periods relatively timestable peaks are apparent at periods of 2 1 2 5 3 1 3 6 4 8 32 33 and for a range between 55 100 years these results offer no strong evidence for solar related forcing of summer temperatures in these regions our previously published reconstruction was limited in its ability to represent long timescale temperature change because of the method used to standardize the original tree ring data here we employ an alternative standardization technique which enables us to capture temperature change on longer timescales considerable variance is now reconstructed on timescales of several centuries in comparison with modern normals 1951 70 generally extended periods when cool conditions prevailed prior to the start of the instrumental record include 500 700 790 870 1110 1150 1190 1360 1570 1750 a d with the most significant cold troughs centred on about 660 800 1140 1580 1620 and 1640 predominantly warm conditions occurred in 720 790 870 1110 and 1360 1570 with peaks of warmth around 750 930 990 1060 1090 1160 1410 1430 1760 and 1820

geochemistry and stable isotope investigation of acid mine drainage associated with abandoned coal mines in central montana usa the great falls lewistown coal field gflcf in central montana contains over 400 abandoned underground coal mines many of which are discharging acidic water with serious environmental consequences areas of the mines that are completely submerged by groundwater have circum neutral ph and relatively low concentrations of metals whereas areas that are only partially flooded or freely draining have acidic ph 3 and high concentrations of metals the ph of the mine drains either decreases or increases after discharging to the surface depending on the initial ratio of acidity mainly al and fe2 to alkalinity mainly hco3 in acidic fe rich waters oxidation of fe2 after exposure to air is microbially catalyzed and follows zero order kinetics with computed rate constants falling in the range of 0 97 to 1 25 mmol l 1 h 1 in contrast fe2 oxidation in near neutral ph waters appears to be first order with respect to fe2 concentration although insufficient data were collected to constrain the rate law expression rates of fe2 oxidation in the field are dependent on temperature such that lower fe2 concentrations were measured in down gradient waters during the day and higher concentrations at night diel cycles in dissolved concentrations of zn and other trace metals mn ni were also noted for down gradient waters that were net alkaline but not in the acidic drains the coal seams of the gflcf and overlying cretaceous sandstones form a perched aquifer that lies 50 m above the regional water table situated in the underlying madison limestone the d and 18o values of flooded mine waters suggest local derivation from meteoric water that has been partially evaporated in agricultural soils overlying the coal mines the s and o isotopic composition of dissolved sulfate in the low ph mine drains is consistent with oxidation of biogenic pyrite in coal under aerated conditions a clear distinction exists between the isotopic composition of sulfate in the acid mine waters and sulfate in the adjacent sedimentary aquifers making it theoretically possible to determine if acid drainage from the coal mines has leaked into the underlying madison aquifer

late holocene paleoecohydrology and carbon accumulation estimates from two boreal peat bogs in eastern canada potential and limits of multi proxy archives abstract the stratigraphy of four peat sequences collected in two peat bogs located in the eastmain river watershed 52 n 76 w james bay lowlands quebec canada was investigated to reconstruct past hydroclimatic conditions of peat accumulation and associated carbon dynamics during the late holocene analyses of macrofossils testate amoebae peat humification c n ratio and bulk density were performed at high resolution along each peat core allowing the potential of each proxy indicator under varying nutrient status and hydroclimatic conditions to be evaluated some synchronous changes were recorded both within and between peatlands suggesting the influence of allogenic factors in the development of these peatlands other reconstructed changes have highlighted autogenic succession processes related to the local geomorphic and hydrologic context highest peat carbon accumulation rates lorca were correlated with either wet conditions or high woody debris percentages suggesting that residence time of the biomass in the acrotelm and the nature of plant material can both influence carbon accumulation rates in peat bogs this study provides the first high resolution paleoecohydrological reconstructions from the mid boreal ecoregion of eastern canada a region in which peatlands occupy 30 to 60 of the land surface

mobilization and speciation of arsenic from hydrothermally altered rock in laboratory column experiments under ambient conditions abstract this paper describes the mobilization and speciation of as found in hydrothermally altered rock under oxic column conditions the altered rock sample was obtained from a tunnel project located in the nakakoshi area of hokkaido japan whose geology is represented by slate shale and sandstone this area has undergone silicification pyritization and argillic alteration resulting in as enrichment of the rock results of the column experiments show that the infiltration rate bulk density and rock bed thickness affected the duration of water residence which in turn influenced the ph of the rock water system coexisting ions most notably ca2 at amounts greater than ca 50 mg l retarded the mobilization of as mobilization of as from the rock with time occurred in two stages stage 1 weeks 1 20 with higher as leaching and stage 2 weeks 20 76 characterized by nearly constant as release in addition pore water as concentrations revealed that the columns developed into two regions the top half where most of the leaching occurred and the bottom part dominated by adsorption thus the mechanism controlling the mobilization of as from the rock is a combination of one or more of the following processes dissolution of soluble as bearing fractions pyrite oxidation and adsorption reactions arsenite as iii was the dominant species in the effluent at the start of the experiment in columns with shorter water residence time and lower ph conditions

evidence from northwest european bogs shows little ice age climatic changes driven by variations in solar activity fluctuations in holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity analyses of both 10 be and 14 c nuclides cone rm that production ratechanges during

changes in solar activity and holocene climatic shifts derived from 14c wiggle match dated peat deposits closely spaced sequences of accelerator mass spectrometer ams 14 c dates of peat deposits display century scale wiggles which can be e tted to the radiocarbon calibration curve by wiggle matching such sequences high precision calendar age chronologiescan be generated which show that changes in mire surface wetness during the bronze age iron age transition c 850 cal bc and the little ice age wolf sporer maunder and dalton minima occurred during periods of suddenly increasing atmospheric concentration of 14 c replicate evidence from peat based proxy climate indicators in northwest europe suggest these changes in climate may have been driven by temporary declines of solar activity carbon accumulation rates of two raised peat bogs in the uk and denmark record low values during the little ice age which ree ects reduced primary productivity of the peat forming vegetation during these periods of climatic deterioration

geochemistry of the rare earth elements and uranium in the acidic berkeley pit lake butte montana abstract filtered 0 45 m and nonfiltered concentrations of rare earth elements ree u zr th ba sc and y were measured as a function of depth in the berkeley pit lake a large acidic mining lake in butte mt the ree show very little variation with depth apart from a slight concentration near the surface presumably due to evaporation the ree profiles of the pit waters show a depletion in light ree when normalized against nasc and the host butte quartz monzonite bqm and a possible enrichment in middle ree vs heavy ree when normalized against bqm all of the ree partitioned weakly into secondary ferric precipitates formed by aging of deep berkeley pit water the measured distribution coefficients increased across the lanthanide series from la kd 7 7 to nd kd 10 3 and then decreased steadily to lu kd 1 4 under the conditions of the berkeley pit lake the aqueous speciation of ree and u is dominated by sulfate complexes because the stability constants of ree sulfate complexes show very little variation across the lanthanide series the observed trends in kd cannot be explained by aqueous complexation despite high concentrations of dissolved ree e g 1 1 mg l ce and u 0 85 mg l saturation indices for all solid phases were strongly negative due to the low ph of the berkeley pit lake 2 3 2 6 the mobility of ree and u is more likely constrained by adsorption or co precipitation with strengite jarosite schwertmannite or other secondary minerals forming in the lake

abrupt holocene indian summer monsoon failures a primary response to solar activity knowledge of the millennial abrupt monsoon failures is critical to understanding the related causes here we extracted proxy indices of indian summer monsoon ism intensity during the early to mid holocene from peat deposits at lake xihu in southwestern china there are a series of abrupt millennial scale episodes of ism weakening inferred from the lake xihu records which are generally synchronous with those inferred from other archives over ism areas an important feature is that the ism failures inferred from the lake xihu proxy indices synchronize well with abrupt changes in solar activity we argue that changes in solar activity play a primary role in producing most of these millennial ism failures while some other causes including freshwater outbursts into the north atlantic ocean and changes in sea surface temperatures of the eastern tropical pacific ocean may have also exerted influences on parts of the millennial ism failures

a 2800 year palaeoclimatic record from tore hill moss strathspey scotland the need for a multi proxy approach to peat based climate reconstructions analyses of plant macrofossils testate amoebae and humification have been carried out on a 2800 year core from tore hill moss a raised bog in the strathspey region of scotland all three analyses were carried out at the same 4 cm intervals allowing exact correlation and the core was dated by nine accelerator mass spectrometry radiocarbon dates and the glen garry tephra layer the results have been combined and compared to present a bog surface wetness bsw record within which the limitations of each proxy method can be assessed and this has highlighted the advantages of a combined rather than a single proxy approach significant wet shifts are recorded at ca cal 560 bc 60 bc ad 430 ad 570 ad 700 ad 1090 and ad 1640 significant shifts to drier periods are also suggested ca cal ad 220 ad 500 and ad 820 some of the recorded shifts and phases are related to phases of wetter and drier climate such as the sub boreal sub atlantic transition the dark age deterioration and the romano british warm period the dark ages are notable as a period of rapid peat accumulation and frequent water table fluctuations time series analysis revealed a significant wet shift cycle of 560 years from the testate amoebae data

holocene hydro climatic change and effects on carbon accumulation inferred from a peat bog in the attawapiskat river watershed hudson bay lowlands canada abstract multiple proxies from a 319 cm peat core collected from the hudson bay lowlands northern ontario canada were analyzed to determine how carbon accumulation has varied as a function of paleohydrology and paleoclimate testate amoeba assemblages analysis of peat composition and humification and a pollen record from a nearby lake suggest that isostatic rebound and climate may have influenced peatland growth and carbon dynamics over the past 6700 cal yr bp long term apparent rates of carbon accumulation ranged between 8 1 and 36 7 g c m 2 yr 1 average 18 9 g c m 2 yr 1 the highest carbon accumulation estimates were recorded prior to 5400 cal yr bp when a fen existed at this site however following the fen to bog transition carbon accumulation stabilized carbon accumulation remained relatively constant through the neoglacial period after 2400 cal yr bp when pollen based paleoclimate reconstructions from a nearby lake mcandrews et al 1982 and reconstructions of the depth to the water table derived from testate amoeba data suggest a wetter climate more carbon accumulated per unit time between 1000 and 600 cal yr bp coinciding in part with the medieval climate anomaly

the nexus between groundwater modeling pit lake chemogenesis and ecological risk from arsenic in the getchell main pit nevada u s a abstract the proliferation of mine pits that intersect the groundwater table has engendered interest in the environmental consequences of the lakes that form after cessation of dewatering the getchell main pit gmp in nevada hosts arsenic sulfide asxsy mineralization e g orpiment and realgar and ambient groundwater as up to 1 8 mg l 1 making groundwater inflow a potentially significant as source to the future pit lake predictive simulations using modflow surfact show that the gmp lake water level will recover to within 99 of the pseudo equilibrium stage within 100 years after the end of dewatering resulting in a 75 m deep terminal pit lake the juvenile gmp lake after 5 years will be a calcium sulfate ph 7 8 water body containing 920 mg l 1 tds and 0 6 mg l 1 as evolving towards a ph 7 9 1580 mg l 1 tds and 0 9 mg l 1 as water body after 100 years the predicted pit lake chemistry is consistent with earlier pit lake water quality after 16 years when the south and center pits precursors to the main pit were allowed to fill during a mining hiatus 1968 1984 the gmp mature pit lake chemistry was used to assess ecological risk to potential local receptors i e mallard duck cliff swallow golden eagle little brown bat spotted sandpiper deer mouse mule deer and cattle arsenic does not strongly bioaccumulate through the food chain at getchell hence pit lake as will not pose an unacceptable risk

high resolution records of late holocene climate change and carbon accumulation in two north west european ombrotrophic peat bogs the peat stratigraphy plant macrofossils colorimetric humification pollen non pollen microfossils carbon nitrogen ratios of three replicate cores from a raised peat bog in the uk walton moss and a single core from a raised peat bog in denmark lille vildmose were examined in an attempt to investigate the relation between long term climate change and changes in species composition of the peat forming vegetation nine wet shifts identified in the monoliths from walton moss and lille vildmose mainly occurred during periods of increasing atmospheric c 14 content because fluctuations in holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity the little ice age lia climatic deteriorations registered in both peat bogs were probably driven by changes in solar activity climatic deteriorations in the three replicate cores from walton moss are not all consistently registered and may reflect the internal variability in the extent of hollow lawn hummock microforms within raised peat bog ecosystems the lowest carbon accumulation values for the walton moss monoliths between ca cal ad 1300 and 1800 and between ca cal ad 1490 and 1580 for lille vildmose occurred during the course of lia climatic deteriorations peat bog primary productivity may have been reduced during the lia owing to lower spring summer temperatures and shorter growing seasons for the peat forming plants species specific higher decomposition rates may have also caused the lower carbon accumulation rates in the peat bogs during the lia c 2002 elsevier science b v all rights reserved

natural and anthropogenic changes in atmospheric co2 over the last 1000 years from air in antarctic ice and firn a record of atmospheric co2 mixing ratios from 1006 a d to 1978 a d has been produced by analysing the air enclosed in three ice cores from law dome antarctica the enclosed air has unparalleled age resolution and extends into recent decades because of the high rate of snow accumulation at the ice core sites the co2 data overlap with the record from direct atmospheric measurements for up to 20 years the effects of diffusion in the firn on the co2 mixing ratio and age of the ice core air were determined by analyzing air sampled from the surface down to the bubble close off depth the uncertainty of the ice core co2 mixing ratios is 1 2 ppm 1 preindustrial co2 mixing ratios were in the range 275 284 ppm with the lower levels during 1550 1800 a d probably as a result of colder global climate natural co2 variations of this magnitude make it inappropriate to refer to a single preindustrial co2 level major co2 growth occurred over the industrial period except during 1935 1945 a d when co2 mixing ratios stabilized or decreased slightly probably as a result of natural variations of the carbon cycle on a decadal timescale

record of volcanism since 7000 b c from the gisp2 greenland ice core and implications for the volcano climate system sulfate concentrations from continuous biyearly sampling of the gisp2 greenland ice core provide a record of potential climate forcing volcanism since 7000 b c although 85 percent of the events recorded over the last 2000 years were matched to documented volcanic eruptions only about 30 percent of the events from 1 to 7000 b c were matched to such events several historic eruptions may have been greater sulfur producers than previously thought there are three times as many events from 5000 to 7000 b c as over the last two millennia with sulfate deposition equal to or up to five times that of the largest known historical eruptions this increased volcanism in the early holocene may have contributed to climatic cooling

interrelated continental sedimentary environments in the central iberian range spain facies characterization and main palaeoenvironmental changes during the holocene a complex holocene system in the central iberian range ne spain has been reconstructed on the basis of sediments recovered from cores and in situ observations small alluvial fans graded into a wide shallow lacustrine area anavieja lake that connected downstream with a carbonate fluvial system with associated vegetated zones the fluvial system was mainly characterized by the development of tufa barriers especially during the first part of the holocene that separated pools or small lakes oncolites detrital tufas calcarenites and marls were deposited in these pools adjacent vegetated areas were covered by macrophytes and were episodically reached by detrital tufa supplies indicating high flood stages high sedimentary rates existed in both the fluvial including the pools and vegetated areas suggesting that despite the common erosion of tufas a clear aggradating evolution existed by contrast very low sedimentary rates were registered in the anavieja lake all the environments but especially the vegetated areas registered the climate evolution during the holocene although the onset of the holocene was characterized by wide climate variability warm and humid conditions dominated during the first part and drier conditions during the second part a water level recovery seems to have been existed during the last millennium this is a good example of the potential of continental systems other than lakes to be useful for palaeoenvironmental and palaeoclimatic studies

a sensitive high resolution record of late holocene climatic change from a raised bog in northern england proxy climatic data in the form of plant macrofossils have been analysed from a 5 m core from bolton fell moss cumbria uk detailed analysis of peat from the upper 50 cm of this core is used to demonstrate a strong correlation between changes in the relative proportion of taxa and known climatic changes over the last 1000 years the record of changes in bog vegetation contained within the peat profile is used to reconstruct changes in bog surface wetness for the latter half of the holocene as bog surface wetness is directly controlled by the prevailing climatic conditions this reconstruction can be viewed as a proxy climate record twelve radiocarbon age estimates on the 5m core suggest that between 50 and 500 cm peat accumulated at a relatively constant rate of 12 4 yr cm 1 the regular sampling intervals thus provide a time series of past bog surface wetness spectral analyses of this series indicates that wetness changes are cyclic with a ca 800 year periodicity

replicability and variability of the recent macrofossil and proxy climate record from raised bogs field stratigraphy and macrofossil data from bolton fell moss and walton moss cumbria england replication of results is a basic tenet of science but in palaeoecology this is very time consuming and the signal is subject to noise the derivation of proxy climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes which are also similar to previous profiles from the same sites it is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed 1998 john wiley sons ltd

the hydrogen and oxygen isotopic composition of precipitation evaporated mine water and river water in montana usa summary the isotopic composition of 42 samples of rain and snow collected in 2004 were used to construct a local meteoric water line lmwl for butte montana the derived equation d 7 31 18 o 7 5 r 2 0 987 represents one of the first published lmwls based on direct precipitation for any location in the northern rocky mountains samples of underground and surface mine waters in butte including the berkeley pit lake and a nearby tailings pond define a linear trend with a much lower slope and intercept than the lmwl d 5 00 18 o 49 5 r 2 0 991 consistent with non equilibrium evaporation at an average relative humidity of roughly 65 detailed evaporation calculations are presented which indicate that the shallow berkeley pit lake was approximately 25 evaporated in october 2003 whereas the surface of the tailings pond was at least 50 evaporated the intersection of the lmwl and mine water evaporation trend was used to calculate the average composition of recharge water to the flooded mine complex d 139 18 o 18 0 these values are considerably lighter than the weighted total of precipitation for the 2004 calendar year d 118 18 o 15 3 which is partly explained by the unusually low snowfall that montana experienced in 2004 based on this study the lmwl recently proposed by kendall and coplen 2001 kendall c coplen t b 2001 distribution of oxygen 18 and deuterium in river waters across the united states hydrological processes 15 1363 1393 from regression of isotopic data from a number of montana rivers is more accurately interpreted as an evaporation line isotopic trends based on river data should be treated with caution particularly in a semi arid region such as montana where rivers are often influenced by dams and irrigation withdrawals

holocene palaeoecological reconstruction of three boreal peatlands in the la grande riviere region quebec canada pollen and macrofossil analyses from central peat cores along with 23 radiocarbon dates were used in palaeoecological reconstructions for three peatlands lg1 lg2 and lg3 within the lower la grande riviere watershed in northern boreal quebec basal ages from lg3 and lg2 indicate up to an 1100 years later and possibly more abrupt tyrrell sea retreat in the lg3 area compared with the timeline for the region both autogenic and allogenic factors were found to have influenced local vegetation succession and rates of peat accumulation internal autogenic factors such as peat accumulation were key elements for the general peatland developmental pathway that followed the classic hydrosere sequence pond fen bog regional climate and hydrography are the main external factors associated with changes in vegetation assemblages surface wetness and consequently rates of peat accumulation the lg2 and lg3 peatlands began developing shortly after 7000 cal bp as shallow ponds with herbaceous freshwater aquatic and e

relative importance of climatic and autogenic controls on holocene carbon accumulation in a temperate bog in southern ontario canada peat cores from wylde lake bog in temperate southern ontario canada were examined to determine factors affecting holocene ecological change and long term rate of carbon accumulation lorca by 1

determining the sun s influence on lateglacial and holocene climates a focus on climate response to centennial scale solar forcing at 2800 cal bp abstract the influence of solar variability on the climate of the lateglacial and holocene periods has been the subject of increasing discussion during the last decade in the mid holocene several studies have identified cold wet events that occur at ca 2800 cal bp and a link with a reduction in solar activity inferred from the 14c record has been postulated we present results from a multi proxy study of peat humification plant macrofossils and testate amoebae from a raised bog at glen west northwest ireland that indicate that dry bog surface conditions were experienced in the north of ireland at the time of the solar anomaly starting at 2800 cal bp with the aid of 14c wiggle matching and tephrochronology an abrupt shift to wetter conditions is dated to ca 2700 cal bp coinciding with a 14c maximum but clearly post dating the 2800 cal bp event identified elsewhere in europe we explore the significance of this apparent lag in the irish record considering the possible role of the ocean in generating spatial and temporal complexities in the climate patterns of the north atlantic region we conclude that these complexities are likely to give rise to time transgressive climate responses around the north atlantic that will only be recognised by more critical chronological approaches

multiproxy late holocene peat records from ireland towards a regional palaeoclimate curve two new peat based climate records from ireland covering the late holocene are presented the sequences are dated by a strong chronological framework formed by ams radiocarbon dates and scps three proxy indicators testate amoebae macrofossils and humification have been determined allowing the limitations and strengths of each to be identified and utilised to provide a bog surface wetness bsw record for both sites age depth models take into account the potential for accumulation rates to vary with bog vegetation the records from each site have been used to derive a combined bsw record that displays changes to a wetter cooler climate from ca ad 30 1920 bp ca ad 310 1640 bp ca ad 805 1145 bp ca ad 1040 910 bp and ca ad 1300 650 bp changes follow closely those identified in a northern britain composite bsw record and largely correspond with lake level data in central france suggesting the main changes in water balance were coherent over a large region correspondence with increases in ird and slower iceland scotland overflow water isow suggests that these changes were related to oceanic forcing influencing the track of dominant westerly air flow over ireland copyright 2007 john wiley sons ltd

14c ams wiggle matching of raised bog deposits and models of peat accumulation abstract high resolution accelerator mass spectrometer ams 14 c dates of selected plant macrofossils from the raised bog engbertsdijksvenen eastern netherlands show century scale wiggles analogous to the radiocarbon calibration curve we used three relative time scales viz based on depth mass and pollen concentration respectively to match the peat ams dates to the calibration curve this procedure is repeated for one conventionally dated core for each relative time scale realistic confidence intervals are calculated depth appears to be the best time scale for certain stratigraphical units of a core this justifies using depth for wiggle matching conventionally dated mire cores published by others even when 14 c errors are larger our evidence shows four major sources of 14 c variation for mire deposits compared to treerings 1 dating error due to sample composition this includes a reservoir effect demonstrated for many bulk peat samples 2 hiatuses causing a sudden leap of peat 14 c age 3 changing accumulation rates apparent from a break in the slope of the peat 14 c ages 4 sampling error these results shed doubt on the assumed continuities in theoretical peat accumulation models both mire stratigraphy and changing accumulation rates can be explained in qualitative hydrological terms more evidence for a previously discovered reservoir effect in bog deposits is presented though the physical biological mechanisms remain uncertain

holocene carbon cycle dynamics based on co2 trapped in ice at taylor dome antarctica a high resolution ice core record of atmospheric co2 concentration over the holocene epoch shows that the global carbon cycle has not been in steady state during the past 11 000 years analysis of the co2 concentration and carbon stable isotope records using a one dimensional carbon cycle model uggests that changes in terrestrial biomass and sea surface temperature were largely responsible for the observed millennial scale changes of atmospheric co2 concentrations

high resolution reconstruction of wetness dynamics in a southern boreal raised bog finland during the late holocene a quantitative approach a high resolution plant macrofossil analysis was applied to investigate wetness dynamics in a southern finnish boreal bog kontolanrahka during the last 5000 years the chronological control and the age depth model were based on 40 ams radiocarbon dates pollen analysis provided information on regional scale vegetation changes macrofossil analysis revealed prominent changes in vegetation assemblages during the late holocene indicating fluctuations in water table the reconstruction suggests that at the coring point which nowadays is a relatively wet lawn habitat type has repeatedly varied between transient communities similar to those currently represented in dry hummocks very wet lawns and even hollows in order to quantify historical changes in water table generalized additive models gam were used to investigate the current relationships between surface plant species and water table depth modern water table measurements and a survey of associated plant communities along moisture gradients prov

holocene climate variability and periodicities in south central sweden as interpreted from peat humification analysis analysis of the decomposition of peat has been used to identify climatic shifts over the last 10 000 years in two raised bogs stomyren and kortlandamossen south central sweden age depth curves have been constructed using radiocarbon dates and tephra layers peat humification data have been subjected to spectral analyses using the lomb scargle fourier method and reveal a periodicity of c 250 years in both records cycles of c 200 yr and c 400 yr were found at stomyren and at kortlandamossen respectively these periodicities could correspond to changes in solar activity levels a test estimating the possible level of noise has been applied to the spectral analyses the humification indices indicate prominent shifts to wetter conditions at c 7500 4300 4200 3700 3500 and 2800 2400 cal yr bp the most distinct drier phases start at c 4500 and 3250 cal yr bp

the disappearance of sphagnum imbricatum from butterburn flow uk the disappearance of the previously abundant moss species sphagnum imbricatum has been investigated at butterburn flow northern england using organic geochemical elemental macrofossil pollen and testate amoebae analyses variations in the assemblage of peat forming plants were tracked using the macrofossil distributions as well as the relative chain lengths of n alkanes and concentrations of 5 n alkylresorcinols and triterpenols no significant changes to the vegetation assemblage could be detected prior to the loss of s imbricatum variations in water depth were reconstructed using a testate amoebae transfer function and inferred qualitatively using bulk elemental composition and biomarkers for changing redox conditions in the bog subsurface the degree of isomerization in the c31 hopanes and the concentrations of bishomohopanol and archaeol pollen analysis reconstructed the landscape surrounding the mire and revealed evidence for human disturbance the results suggest that bog surface wetness increased with the transition from sphagnum imbricatum to sphagnum magellanicum but the increase was not large and s imbricatum had previously survived similar periods of wetness however the loss of s imbricatum coincides with increasing human disturbance surrounding the bog which may have altered nutrient inputs to the bog surface from agriculturally derived dust to the detriment of s imbricatum but to the benefit of s magellanicum and eriophorum vaginatum it is proposed here that the stresses imposed by the combination of changing nutrient inputs and a rapidly rising water table drove the disappearance of s imbricatum from butterburn flow at c cal ad 1300

distributions of bomb 14 c biogeochemistry and elemental concentration in hani mire peat profiles ne china implications of environmental change abstract two 50 cm long peat cores from the hani mire on the western slope of the changbai mountains northeastern china were collected for investigating physical biological and geochemical processes of the peatland in response to recent climate change the 14c dating using accelerator mass spectrometry ams on the peat cores provides a nuclear bomb carbon curve which is used for peat chronological construction the sedimentation rate sr of core s1 from a sphagnum magenllanicum hummock in the hani mire was about 0 98 cm y and deposited from 1957 2008 ce whereas the sr of core s2 from s palustre hummock 1 km apart from s1 was 1 59 cm y and accumulated during 1976 2008 the discrepancy of the srs may mainly be attributed to the different inorganic material supplies from surface runoff which affected growth of sphagnum spp at different sites with lower rate corresponding to higher inorganic contents higher ti ca and mg contents thus lower values of loss on ignition loi on the other hand the two cores had similar values and variation trends in the ph c n n and p contents and dry bulk density dbd implying that the organic source and decomposition were similar under the same climatic conditions the variations of toc c n and pb content in the peat cores matched well with the 5 y running average of local annual precipitation record with higher toc and c n but lower pb content corresponding to higher rainfall and vice versa these properties in the meso oligotrophic peat sequences can reflect climatic changes the recent rates of carbon accumulation rerca for s1 and s2 calculated from the toc dbd and sr were averaged 121 6 24 3 and 175 5 35 1 g m2 y respectively

geochemistry water balance and stable isotopes of a clean pit lake at an abandoned tungsten mine montana usa abstract the calvert mine is a small tungsten rich scheelite skarn deposit in a remote mountainous region of southwest montana usa the open pit mine closed in the 1970s and subsequently flooded to form a pit lake that is roughly conical in shape 30 m deep and 120 m in diameter with no surface inlet or outlet the lake is holomictic with a groundwater flow through hydrology and an estimated residence time of 2 5 5 y water isotopes show that the lake is at an approximate steady state with respect to water balance and has experienced 30 evaporation the lake has a near neutral ph exceptional clarity and extremely low concentrations of nutrients sulfate and most metals including tungsten manganese concentrations are slightly elevated and increase with depth towards the sediment water interface despite seasonally anoxic conditions in the deep water dissolved fe concentrations are orders of magnitude lower than mn suggesting that insufficient organic carbon is present in the sediment of this oligotrophic lake to drive bacterial fe reduction based on stable isotope fingerprinting diffuse seepage that enters a nearby headwater stream at the base of a large waste rock pile can be directly linked to the partially evaporated pit lake however this seepage has neutral ph and low metal concentrations and poses no threats to the environment stable isotopes of dissolved inorganic carbon dic and dissolved oxygen do are used to track the relative importance of photosynthesis and respiration with depth in summer a zone of high productivity exists near the base of the chemocline releasing do that is isotopically light respiration exceeds photosynthesis below the secchi depth which causes do concentrations to approach zero towards the bottom of the lake in winter thick ice and snow cover prohibits photosynthesis however because of the low nutrient content most of the volume of the lake remains oxic through the winter overall the calvert lake is a good example of a pit lake formed from metal mining that has excellent water quality which is a result of its favorable geology paucity of sulfide minerals and hydrology flow through lake with short residence time in a temperate climate

improving the time control of the subboreal subatlantic transition in a czech peat sequence by 14c wiggle matching to achieve an optimal time control for a late subboreal to early subatlantic peat sequence from pancavska louka in the czech republic different strategies are applied to convert a series of radiocarbon dates into a calendar time scale the methods of selection and preparation of the samples for ams 14c dating are presented the results of calibrating single radiocarbon dates are compared with a 14c wiggle match strategy as the accumulation rate of the peat was not constant the concentrations of arboreal pollen are used to estimate the accumulation rate changes and to correct for these changes the resulting time control represents the best solution for this peat sequence with the methods currently available

use of paleo records in determining variability within the volcanism climate system abstract volcanic eruptions that inject large quantities of sulfur rich gases into the stratosphere have the capability of cooling global climate by 0 2 0 3 c for several years after the eruption equatorial eruptions will impact global climate whereas mid latitude eruptions can cool climate in the hemisphere of origin magnitude of cooling varies by latitude and it is possible for warming to occur in certain regions primarily during the winter although instrumental records have been used to quantify the volcanic impact on climate they are limited in their temporal and spatial coverage and the style and magnitude of eruptions occurring over the two centuries of instrumental records is limited a thorough evaluation of the range of variability in the volcanism climate system requires a multidisciplinary approach that includes the analysis of ice core records geological data atmospheric measurements and visual phenomena tree ring records and other proxy data evaluation of these longer time series indicates that multiple volcanic eruptions have the potential to force climate over decadal to multi decadal time frames especially when these eruptions enhance or extend pre existing cool conditions on the other hand a lack of climatically significant eruptions may result in warmer average temperatures over decadal time frames because the volcanic cooling component within the climate system is absent mega eruptions like the toba eruption of 71 000 73 000 yr ago may impact climate on centennial time frames through positive feedback mechanisms evidence exists which indicates that environmental changes associated with rapid climatic fluctuations such as crustal loading unloading with glaciation deglaciation and variability in glacial meltwater loading on ocean basins may cause an increase in volcanic activity

solar modulation of cosmogenic nuclide production over the last millennium comparison between 14c and 10be records for about the last 30 years it has been recognized that the high frequency component of the tree rings 14c 12c record is dominated by the modulation of the cosmic ray flux by the solar wind in particular it has been demonstrated that the three most recent periods of low sunspot occurrence were characterized by high values of atmospheric 14c 12c during the last millennium other periods of high 14c 12c values were observed but their solar origin is still debatable in the present work we compare these fluctuations with an independent record of cosmogenic 10be measured in ice from the south pole to check the solar origin of the observed 14c 12c variations in order to compare quantitatively the results obtained on 10be and 14c it is necessary to take into account the different behaviour of these two cosmogenic isotopes and especially the damping effect of the carbon cycle in the case of 14c as an input to a 12 box numerical model we used the relative fluctuations of the 10be concentrations record measured in south pole ice and converted it into a synthetic 14c record we took into account the fact that 10be modulation is enhanced in polar regions due to the orientation of the geomagnetic field as expected the fluctuations of the modelled 14c record are much smaller a factor of 20 than those observed for the raw 10be record in addition the variations are smoother and shifted in time by a few decades the 10be based 14c variations closely resemble the 14c measurements obtained on tree rings r 0 81 in particular it is easy to identify periods of maximal 14c 12c which correspond to solar activity minima centred at about 1060 1320 wolf 1500 sporer 1690 maunder and 1820 dalton yr a d cross correlation calculations suggest that there is no significant lag between the 10be based 14c and the tree ring 14c records our study strongly suggests the dominance of the solar modulation on the cosmonuclide production variations during the last millennium

a holocene co2 record from the stomatal index of subfossil salix herbacea l leaves from northern sweden a stomatal based method of palaeo co2 estimation has been applied to a temporally detailed sequence of leaves from a high latitude lake 68 n in northern sweden spanning the last 9000 years the resulting atmospheric co2 reconstruction documents the onset of a gradual increase c 5000 years before present indicating that the carbon cycle has not been in steady state over this time stable carbon isotope 13c measurements of the subfossil leaves constrain the interpretation of the inferred changes in the operation of the global carbon cycle the 13c data reveal no marked or systematic shifts towards more negative values indicating that the co2 addition to the atmosphere 5000 1000 yr bp may have been predominantly of oceanic origin

late holocene climatic changes in tierra del fuego based on multiproxy analyses of peat deposits a ca 1400 yr record from a raised bog in isla grande tierra del fuego argentina registers climate fluctuations including a medieval warm period although evidence for the little ice age is less clear changes in temperature and or precipitation were inferred from plant macrofossils pollen fungal spores testate amebae and peat humification the chronology was established using a 14c wiggle matching technique that provides improved age control for at least part of the record compared to other sites these new data are presented and compared with other lines of evidence from the southern and northern hemispheres a period of low local water tables occurred in the bog between a d 960 1020 which may correspond to the medieval warm period date range of a d 950 1045 generated from northern hemisphere tree ring data a period of cooler and or wetter conditions was detected between ca a d 1030 and 1100 and a later period of cooler wetter conditions estimated at ca cal a d 1800 1930 which may correspond to a cooling episode inferred from law dome antarctica

variation in the composition of apatite through the merensky cyclic unit in the western bushveld complex microprobe analysis of interstitial apatite from a 100 m section through the merensky reef of the bushveld complex reveals that this stratigraphic section marks a transition from cl rich to more f rich compositions in the critical and main zones respectively apatite compositions across the section vary by more than 80 mole percent in the chlorapatite component the trend of decreasing cl concentration with stratigraphic height is not regular and cl contents in apatites from some samples may vary as much as 50 mole percent la 2 o 3 and ce 2 o 3 tend to be enriched in the more melanocratic orthocumulate parts of the section sro concentrations of apatite show an increase with stratigraphic position a trend which is opposite that observed in coexisting cumulus plagioclase the data are consistent with mineralogic and textural evidence for an influx of cl rich vapor into the cumulus section which has affected the cl f variations through the lower portion of the bastard unit this influx occurred above the crystallization temperature of apatite 1 000 degrees 1 050 degrees c it is suggested that much of the modal variation seen in the section may be the result of shifts in liquidus field boundaries caused by gain or loss of volatile components from the melt

solar influences on holocene climatic changes illustrated by correlations between past lake level fluctuations and the atmospheric 14c record chronological correlations established at different time scales among the lake level fluctuations in the jura and french subalpine ranges glacier movements in the swiss and austrian alps and the atmospheric 14c record during the last 7 millennia show coincidences between lake level rises glacier advances and high 14c production and vice versa these correspondences suggest that the short term 14c variations may be an empirical indicator of holocene palaeoclimates and argue for possible origins of holocene climatic oscillations 1 the varying solar activity refers to secular climatic oscillations and to major climatic deteriorations showing a ca 2300 yr periodicity 2 a question is raised about a relationship between the earth s magnetic field and climate first the weak strength periods of the earth s dipole magnetic field between 3800 and ca 2500 b c coincide with higher climate variability and vice versa second the ca 2300 yr periods revealed by the 14c record and also by the major climatic deteriorations re corded in jurassian lakes ca 1500 a d ca 800 b c and ca 3500 b c coincide with the ca 2300 yr periods revealed by the earth s nondipole geomagnetic field the present warming induced by anthropogenic factors should be intensified during the next few centuries by natural factors of climate evolution

sphagnum δ13c values as indicators of palaeohydrological changes in a peat bog late holocene peat stratigraphy of a canadian boreal peat bog was examined to evaluate the poten tial of sphagnum 13 c values as surface moisture proxy indicators isotopic measurements were compared to tes tate amoebae inferred water table depth reconstructions plant macrofossil assemblages and past decompo sition levels inferred by colorimetric humification ams radiocarbon dates were coupled with 210 pb dates to establish peat chronology although the mechanisms underlying carbon fractionation processes in peatlands are not well understood we demonstrate that sphagnum 13 c values have potential for palaeohydrological recon structions since variations presented by the isotopic values can generally be correlated with the other proxy records especially during drier episodes

late holocene climate change and human impact recorded in a south swedish ombrotrophic peat bog abstract a peat core from a raised bog in southern sweden was examined plant macrofossils pollen non pollen microfossils colorimetric humification carbon nitrogen ratios bulk densities loss on ignition to investigate the effects of climate change and human impact on the plant species composition and carbon accumulation of the peat forming vegetation 14c wiggle match dating was applied for fine resolution dating cooling at the start of the little ice age was reflected by a decline of thermophilous trees from the pollen record between ca cal ad 1275 1590 coinciding with increases in atmospheric 14c pointing to decreases of solar activity wolf and sporer minimum human impact also decreased later the effect of human impact was clearly visible in the form of a black brown decomposed peat layer the top of which marks a gap of more than 300 years artificial drainage probably caused secondary decomposition and oxidation of the peat from ca cal ad 1960 the water table of the peat bog was restored following construction of a road and raised bog vegetation regenerated

quantifying spatial and temporal holocene carbon accumulation in ombrotrophic peatlands of the eastmain region quebec canada 1 northern peatlands represent important stocks of organic carbon c peatland c dynamics have the potential to influence atmospheric greenhouse gas concentrations and are therefore of interest concerning future climate change quantification of holocene variations in peat c accumulation rates is often based on a single deep core however deep cores may overestimate accumulation rates when extrapolated to the ecosystem scale we propose a reconstruction of c sequestration patterns based on multiple cores from three ombrotrophic peatlands in boreal quebec canada both total c accumulation and temporal variations herein were quantified radiocarbon dated stratigraphies from different sections resulted in peatland specific age depth models peatland initiation started rapidly after deglaciation around 7500 cal bp vertical accumulation slowed down in the course of the holocene whereas lateral expansion was rapid in the early stages but slowed down near mid holocene total c accumulation showed maximum rates between 5250 and 3500 cal bp with a regional mean holocene apparent rate of 16 2 g m 2 yr 1 the eastmain peatlands have been modest sinks of organic c compared to those of alaska western canada and western siberia although differences in calculation methods hamper direct comparisons considering within peatland dynamics maximum total c sequestration coincided with a period of slowing down in both lateral expansion and vertical accumulation late holocene diminishing peatland c sink functions have been attributed to autogenic as well as allogenic factors height induced surface drying and or neoglacial cooling effects may have forced the slowing down of c sequestration in the studied bogs results further show that in order to obtain an accurate quantification of past c sequestration reconstructions of peatland expansion are essential

a mineral quantification method for wall rocks at open pit mines and application to the martha au ag mine waihi new zealand abstract pit lakes that result from open pit mining are potential water resources or potential environmental problems depending on lake water quality wall rock mineralogy can affect lake chemistry if surface water inputs and or groundwater inputs and or lake water in contact with submerged wall rocks react with the wall rock minerals this study presents a mineral quantification method to measure the distribution and concentration of wall rock minerals in open pit mines and applies the method to the martha epithermal au ag mine waihi new zealand heterogeneous ore deposits like martha require a large number of wall rock samples to accurately define mineral distributions x ray diffraction analyses of 125 wall rock samples identified the most abundant minerals in the wall rocks as quartz adularia albite illite chlorite kaolinite pyrite and calcite distribution maps of these minerals defined 8 relatively homogenous areas of wall rock referred to as mineral associations weakly altered propylitic fresh argillic weathered argillic oxidized potassic quartz veins and post mineralization deposits x ray fluorescence leco furnace and neutron activation analyses of 46 representative samples produced the geochemical dataset used to assign quantities of elements to observed minerals and to calculate average mineral concentrations in each association thin section petrography and calcite concentrations from sobek acid digestions confirm the calculated mineralogy providing validation for the method calcite and pyrite concentrations allowed advanced acid base accounting for each mineral association identifying 3 potential acid producing associations and one potential acid neutralizing association the results target areas where detailed hydrologic and kinetic tests would be valuable in the next stage of pit lake evaluation detailed understanding of wall rock mineralogy will help strengthen predictions of pit lake water quality

late holocene human impact and climate change recorded in a north swedish peat deposit abstract a peat core from a mire with poor fen lawns and ombrotrophic hummock strings in northern sweden was examined plant macrofossils pollen non pollen microfossils testate amoebae colorimetric humification carbon nitrogen ratios bulk densities loss on ignition to investigate the effects of climate change and human impact on the plant species composition and peat accumulation of the peat forming vegetation during the last 1700 yr 14 c wiggle match dating was applied for high precision dating the lappmyran region was dominated by pinus and picea forest changes in land use patterns and population density were visible in the pollen record of the regional vegetation juniperus and rumex acetosa type pollen indicated the presence of grazed land in the area between ad 1500 and 1950 the vegetation at the coring spot gradually became ombrotrophic the local plant and testate amoebae compositions reflect changes in surface wetness caused by changes in precipitation and the internal dynamics of the bog a wet interval was observed during the maunder minimum of solar activity the presence of drepanocladus fluitans indicates less ombrotrophic conditions during this period probably caused by the inflow of minerogenic water from upslope owing to increased precipitation the reconstructed water table shows agreement with precipitation measurements which were available since ad 1860

evidence for climatic deteriorations associated with the decline of sphagnum imbricatum hornsch ex russ in six ombrotrophic mires from northern england and the scottish borders the decline of sphagnum imbricatum from the peat stratigraphy of six ombrotrophic mires bolton fell moss and walton moss raeburn flow and bell s flow and coom rigg moss and felecia moss has been investigated using colorimetric humification quantitative plant macrofossil and testate amoebae analyses the chronology of each peat profile was determined by radiocarbon assay and pollen land use correlations palaeoclimate reconstructions have been made by linking known documentary historical changes in climate and other proxy climate records to those inferred from the sites investigated in the study region in two of the ombrotrophic mires examined there are wet shifts associated with the decline and local extinction of s imbricatum which are dated to cal ad 1160 1400 raeburn flow and bell s flow in coom rigg moss and felecia moss wet shifts are also associated with the decline and local extinction of s imbricatum between cal ad 1395 1485 the decline of s imbricatum from two other ombrotro

influence of climate change and human activities on the organic and inorganic composition of peat during the little ice age el payo mire w spain the study of environmental change during the little ice age lia offers a great potential to improve our current understanding of the climate system and human environment interactions here a

a multiproxy climate record from a raised bog in county fermanagh northern ireland a critical examination of the link between bog surface wetness and solar variability a proxy climate record from a raised bog in county fermanagh northern ireland is presented the record spans the interval between 2850 cal yr bc and cal yr ad 1000 and chronological control is achieved through the use of tephrochronology and 14c dating including a wiggle match on one section of the record palaeoclimatic inferences are based on a combination of a testate amoebae derived water table reconstruction peat humification and plant macrofossil analyses this multiproxy approach enables proxy specific effects to be identified major wet shifts are registered in the proxies at ca 1510 cal yr bc 750 cal yr bc and cal yr ad 470 smaller magnitude shifts to wetter conditions are also recorded at ca 380 cal yr bc 150 cal yr bc cal yr ad 180 and cal yr ad 690 it is hypothesised that the wet shifts are not merely local events as they appear to be linked to wider climate deteriorations in northwest europe harmonic analysis of the proxies illustrates statistically significant periodicities of 580 423 373 307 and 265 years that may be related to wider holocene climate cycles this paper illustrates how the timing of climate changes registered in peat profiles records can be precisely constrained using tephrochronology to examine possible climatic responses to solar forcing relying on interpolated chronologies with considerable dating uncertainty must be avoided if the climatic responses to forcing mechanisms are to be fully understood copyright 2007 john wiley sons ltd

information on past solar activity and geomagnetism from 10 be in the camp century ice core a nearly continuous record of the concentration of 10be from ice core data is compared with the tree ring derived record for 14c over the same period and it is found that short term trends in these data sets provide a record of solar activity no definitive relationship between the long term trends and the geomagnetic dipole moment is found

forest history peatland development and mid to late holocene environmental change in the southern taiga forest of central european russia understanding the long term ecological dynamics of boreal forests is essential for assessment of the possible responses and feedbacks of forest ecosystems to climate change new data on past forest dynamics and peatland development were obtained from a peat sequence in the southern valdai hills european russia based on pollen plant macrofossil micro charcoal peat humification and testate amoeba analyses in terms of vegetation history the results demonstrate a dominance of broadleaved forests in the study area from 7000 4000 cal yr bp picea was initially a minor component of this forest but increased in cover rapidly with climatic cooling beginning at 4000 cal yr bp becoming the dominant species broadleaved species persisted until 900 cal yr with evidence for intensified felling and forest management over recent centuries over the last four hundred years there is evidence for widespread paludification and the establishment of picea sphagnum forests these data demonstrate how modern wet woodlands have been shaped by a combination of climatic and anthropogenic factors over several millennia the results also demonstrate the value of a multiproxy approach in understanding long term forest ecology

dating of recent lake sediments in the united kingdom and ireland using spheroidal carbonaceous particle scp concentration profiles spheroidal carbonaceous particles scps produced from fossil fuel combustion are found in lake sediments and provide a historical record of atmospheric pollutant deposition the sediment record of these particles is remarkably consistent and the main features are now seen throughout europe and beyond once the scp record from a region has been established using accurately dated cores scp profiles can be used to determine dates at other sites in the region this technique was developed in sweden brit until recently has had limited use in the uk and ireland as the most useful dating feature the subsurface peak was not present in all cores in recent cores this can now almost always be observed dating features for uk and irish cores are found to differ slightly between regions the potential exists for extra dates to be allocated to a profile by using characterisation of scp surfaces to determine changes in fuel type use dates could then be allocated to these changes using documentary sources to derive combustion histories in future years scp dating will become increasingly valuable especially for mid to late nineteenth century sediments as continual decay renders 210 pb progressively less useful for this time interval

effects of human impact and climate change during the last 350 years recorded in a swedish raised bog deposit a peat core from an ombrotrophic mire in central sweden was analysed for multi proxy indicators plant macrofossils pollen non pollen microfossils testate amoebae colorimetric humification carbon nitrogen ratios bulk densities loss on ignition to evaluate the relative contributions of climate change and human impact on vegetation and peat accumulation during the last c 350 years 14c wiggle match dating was applied for high precision dating testate amoebae assemblages were used to reconstruct past water table depths and compared with other proxies and instrumental climate data from the mid 18th century onwards changes in mire surface wetness were mainly caused by climate change precipitation and evaporation but the internal dynamics of the local bog vegetation may also have played a role in the recorded water table changes the human impact signal in the pollen data was compared with swedish population and land use data a link between climate change human impact openness of the vegetation and demographic change was found cold and wet periods show a decrease in human impact and open land indicators in the pollen data followed by an increase in death rate and or an increase in emigration