reconstructing high resolution climate using ct scanning of unsectioned stalagmites a case study identifying the mid holocene onset of the mediterranean climate in southern iberia the forcing mechanisms responsible for the mid holocene onset of the mediterranean type climate in south western europe are currently unclear but understanding these is critical for accurate climate projections under future greenhouse gas warming additionally regional studies that present conflicting patterns for the onset and advancement of mediterranean climatic conditions complicate definitively ascribing causality here we use a new high resolution stalagmite density record obtained non destructively using computed tomography ct scanning to reconstruct southern iberian climate between 9 3 and 2 9 ka bp we suggest that stalagmite density can be used as a water excess proxy with lower densities associated with more variable drip rates possibly reflecting increased seasonality consistent with expectations from previous studies of speleothem textures and crystal fabrics our results reveal an early holocene humid interval and mid holocene year round aridity that preceded the onset of mediterranean climate at 5 3 ka bp in southern iberia using this new dataset combined with previously published results we link the gradual advancement of the mediterranean climate to the southward migration of the north atlantic subtropical high induced by an orbitally driven decrease in northern hemisphere insolation future anthropogenic warming could result in a reversal of this trend a northward migration of the north atlantic subtropical high and a return to year round aridity in south western europe

the vegetation and climate history of the last glacial cycle in a new pollen record from lake fimon southern alpine foreland n italy abstract the sediments of lake fimon n italy contain the first continuous archive of the late pleistocene environmental and climate history of the southern alpine foreland we present here the detailed palynological record of the interval between termination ii and the last glacial maximum the age depth model is obtained by radiocarbon dating in the uppermost part of the record downward we correlated major forest expansion and contraction events to isotopic events in the greenland ice core records via a stepping stone approach involving intermediate correlation to isotopic events dated by tims u th in alpine and apennine stalagmites and to pollen records from marine cores of the iberian margin modelled ages obtained by bayesian analysis of deposition are thoroughly consistent with actual ages with maximum offset of 1700 years sharp expansion of broad leaved temperate forest and of sudden water table rise mark the onset of the last interglacial after a treeless steppe phase at the end of penultimate glaciation this event is actually a two step process which matches the two step rise observed in the isotopic record of the nearby antro del corchia stalagmite respectively dated to 132 5 2 5 and 129 1 5 ka at the interglacial decline mixed oak forests were replaced by oceanic mixed forests the latter persisting further for 7 ka till the end of the eemian succession warm temperate woody species are still abundant at the eemian end corroborating a steep gradient between central europe and the alpine divide at the inception of the last glacial after a stadial phase marked by moderate forest decline a new expansion of warm broad leaved forests interrupted by minor events and followed by mixed oceanic forests can be identified with the north alpine saint germain i the spread of beech during the oceanic phase is a valuable circumalpine marker the subsequent stadial interstadial succession lacking the telocratic oceanic phase is also consistent with the evidence at the north alpine foreland the middle wurmian full glacial is marked by persistence of mixed forests dominated by conifers but with significant lime and other broad leaved species a major arboreal pollen decrease is observed at modelled age of 38 7 0 5 ka larch expansion and last occurrence of lime which has been related to heinrich event 4 the evidence of afforestation persisting south of the alps throughout most of mis 3 contrasts with a boreal and continental landscape known for the northern alpine foreland pointing to a sharp rainfall boundary at the alpine divide and to southern air circulation this is in agreement with the alpine paleoglaciological record and is supported by the pressure and rainfall patterns designed by mesoscale paleoclimate simulations strenghtening the continental high pressure during the full glacial triggered cyclogenesis in the middle latitude eastern europe and orographic rainfall in the eastern alps and the balkanic mountains thus allowing forests development at current sea level altitudes

tentative correlation of pollen records of the last interglacial at grande pile and ribains with marine isotope stages eemian lake deposits in grande pile and ribains france correlate with marine isotope substages mis 5e and 5d as delimited in two pollen bearing deep sea cores off portugal the eemian forests in france lasted for approximately 20 millennia from at least 126 000 to ca 107 000 yr b p oscillatory climate deteriorations began about 115 000 yr ago an intense cold spell affected the region approximately 110 000 yr ago

modelling the mid late holocene evolution of the huelva estuary and its human colonization south western spain abstract the major changes that occurred in the southwestern estuaries of the spanish atlantic coast during the last 6500 yr bp were simultaneous to human settlement and therefore the understanding of their coastal evolution will help interpreting human patterns in these areas the study of the morpho sedimentary features of new outcrops appearing in the middle sector of saltes island huelva estuary spain has been used to develop a model to understand the complex evolution of sand barriers than can be applied to similar inlets along the atlantic iberian coast the first human settlements 6000 4000 yr bp in the early huelva estuary tinto and odiel rivers were located in the ancient coastal banks or in the nearby hills from 4000 yr bp onwards the estuarine sediments started to emerge as sand barriers and chenier plains prograding towards the mouth as the littoral strands stabilized morphologically they were colonized by human settlements in successive periods the oldest inland almendral and more recent outward cascajera the study of the upper sedimentary layers of la cascajera barrier display a tempestitic sequence of landward progradational washover fans the calibrated and modelled ams dates in marine shells provide a storminess time range between the second half of first century bce and the entire first century ce sedimentary records are useful to evaluate environmental changes either from natural or anthropogenic causes such as global and climate change the interrelationship between the archaeological findings mainly salting fish factories and old ports and the morpho sedimentary evolution at the mouth of the tinto and odiel rivers allows us to highlight not only the huelva estuary s dynamics evolution but also the possible regional patterns of human habitation from the beginning of the present sea level highstand middle holocene

the spatial distribution and source of arsenic copper tin and zinc within the surface sediments of the fal estuary cornwall uk abstract estuarine sediments commonly form major sinks for contaminants released during industrial activity many industrial processes lead to the release of metals initially in solution which can then be adsorbed on to for example fe hydroxides or clay minerals however in the mining industry there are two major contaminant waste streams 1 metals discharged in solution via mine drainage and 2 particulate grains of the ore forming or related minerals released after ore processing the release of particulate waste can have a major long term impact on environmental geochemistry in this study we have mapped the distribution of arsenic copper tin and zinc within the surficial sediments of the fal estuary cornwall uk an area that drains a historically important polymetallic mining district there are clear spatial variations in the contaminants with the highest levels 2800 p p m as 5000 p p m cu 3000 p p m sn and 6000 p p m zn within restronguet creek on the western side of the estuary mineralogical studies show that small 20 m grains of detrital arsenopyrite chalcopyrite cassiterite and sphalerite are very abundant within the surface sediments most of the sulphide grains are fractured but mineralogically unaltered although some grains show alteration rims caused by oxidation of the sulphides the geochemistry and mineralogy are indicative of sediment supply from the discharge of particulate waste into the estuary during historical mining activity subsequently this particulate waste has been largely physically and biologically reworked within the surface sediments although considerable effort has been made to minimize contaminants released via mine drainage into the estuary the potential flux of contaminants present within the intertidal and subtidal sediments has not been addressed benthic invertebrates living within the area have adapted to be metal tolerant and it is likely that the dominant source of bioavailable metals is a result of alteration of the particulate mine waste present within the intertidal and subtidal sediments

dancing to the rhythms of the pleistocene early middle paleolithic population dynamics in nw iberia duero basin and cantabrian region the northwest of iberia has yielded one of the most complete european middle paleolithic records despite this wealth of information very little is known about population dynamics during this period for that reason the main concern of this paper is to provide socio environmental models that may help explain early middle paleolithic emp population dynamics in nw iberia assessing to what extent they were shaped by climate forces the archaeological record is analyzed on the basis of the heuristics of ecological models already employed in the european pleistocene record but never at a regional scale in order to detect long term changes in the composition of emp populations and the environmental biological and sociocultural process influencing those changes according to the models proposed we have detected a long term population dynamic between mis 11 and mis 6 characterized by low environmental stress high biological productivity interaction among populations and sociocultural complexity eventually this population dynamic was broken due to an extreme climate phase in late mis 6 that had a profound impact on populations and sociocultural structures as a result the upper pleistocene population of nw iberia was concentrated in the cantabrian region this area became an isolated neanderthal glacial refugium that hosted a population with different origins and fragile long term demographic stability

appearance of an enigmatic pb source in south america around 2000 bp anthropogenic vs natural origin abstract neotropical wetlands in the paramo a unique alpine tundra ecosystem region of south america have the potential to be natural archives for metal pollution by modern and past populations an organic rich sediment core from the el triunfo mire located in the paramo region provides a record of natural and anthropogenic metal sources in the northern andes during the last four millennia the triunfo record is complex as the mire is located in the northern volcanic zone nvz and receives direct input of volcanic material regardless of the volcanic input calculated metal enrichment factors normalized to sc show metal enrichment in the northern andes around 2000 years ago and again in recent industrial times a number of samples show a shift to lower pb isotope ratios indicating the appearance of a new enigmatic pb source around 2000 years ago the topmost layer of the core shows the lowest pb isotope ratios reflecting input of modern anthropogenic pb in contrast to pb nd isotopes do not show significant variations along the entire core indicating mostly volcanic material input to the mire the decoupling between nd and pb isotopes indicates that the enigmatic pb source must be anthropogenic in origin based on the dominant atmospheric currents in the region the el triunfo mire can receive input from long distance and local sources dispersion simulations validate the possibility of pollutant particle transport from europe to the northern hemisphere neotropics as the first metal enrichment coincides with the roman empire times the el triunfo pb isotopes are compared to contemporary peat records from europe all records show similar decrease in the pb isotope ratios due to anthropogenic pb input small pb isotope differences between a record from spain and el triunfo indicate that the enigmatic pb that appeared around 2000 years ago in the mire is unlikely to have originated from long distance roman empire pollution instead a group of deposits namely san lucas san martin de loba and el bagre located in north central colombia show low pb isotope ratios that can potentially explain the observed pb signal in the el triunfo sediments the deposits are located up wind along the predominant atmospheric currents in the region therefore it is plausible that mining activities in the area of san lucas san martin and or el bagre released pb in the atmosphere that was transported and deposited in the el triunfo mire these deposits are not associated with the known regions of influence of any of the early pre hispanic cultures in colombia and there is no evidence for mining in this region around 2000 years ago however given that all other possibilities are unlikely the appearance of lower pb isotope ratios in the mire suggests the onset of mining in the region at least 400 years earlier than the available archaeological evidence at present the el triunfo mire record can be used as indirect evidence for significant metal exploitation by early pre hispanic cultures in the northern andes as early as 2000 years ago

joining up land and marine seismic data case study from procida and ventotene islands tyrrhenian sea italy abstractthe seismic refraction survey routinely used to obtain information on subsurface geology has a limited use in the foreshore zone we have evaluated a nonstandard approach to acquire seismic data in the backshore foreshore area joining up land and marine seismic data the innovative part was the acquisition of a continuous seismic profile that allowed the recording of high resolution data in a transition zone tz to establish an integrated approach for improving the land marine seismic model in areas characterized by a complex near surface geology to achieve this objective two seismic tests were carried out along the beaches of the tyrrhenian islands of procida and ventotene we defined the p wave vp and s wave velocities vs with depth by integrating the tomography of the refracted first arrivals vp velocities versus depth with the inversion of the phase velocities dispersion curves extracted from the surface waves 1d vs velocities models working with both seismic methods allowed us to o

a case study of the internal structures of gossans and weathering processes in the iberian pyrite belt using magnetic fabrics and paleomagnetic dating in the rio tinto district of the iberian pryrite belt of south spain the weathering of massive sulfide bodies form iron caps i e true gossans and their subsequent alteration and re sedimentation has resulted in iron terraces i e displaced gossans to study the stucture and evolution of both types of gossans magnetic investigations have been carried out with two foci 1 the characterisation and spatial distribution of magnetic fabrics in different mineralised settings including massive sulfides gossans and terraces and 2 paleomagnetic dating hematite has been identified as the suceptibility carrier in all sites and magnetic fabric investigation of four gossans reveals a vertical variation from top to bottom with 1 a horizontal foliation refered to as mature fabric in the uppermost part of the primary gossans 2 highly inclined or vertical foliation interpreted as immature fabric between the uppermost and lowermost parts and 3 a vertical foliation interpreted to be inherited from hercynian deformation in the lowermost part of the profiles in terraces a horizontal foliation dominates and is interpreted to be a sedimentary fabric rock magnetic studies of gossan samples have identified goethite as the magnetic remanence carrier for the low temperature component showing either a single direction close to the present earth field pef direction or random directions maghemite hematite and occasionally magnetite are the remanence carriers for the stable high temperature component that is characterized by non pef directions with both normal and reversed magnetic polarities no reliable conclusion can be yet be drawn on the timing of terrace magnetization due to the small number of samples in gossans the polarity is reversed in the upper part and normal in the lower part this vertical distribution with a negative reversal test suggests remanence formation during two distinct periods remanence in the upper parts of the gossans is older than in the lower parts indicating that the alteration proceeded from top to bottom of the profiles in the upper part the older age and the horizontal mature fabric is interpreted to be a high maturation stage of massive sulfides alteration in the lower part the age is younger and the inherited imature vertical hercynian fabric indicates a weak maturation stage these two distinct periods may reflect changes of paleoclimate erosion and or tectonic motion

petrographic and isotopic evidence for holocene long term climate change and shorter term environmental shifts from a stalagmite from the serra do courel of northwestern spain and implications for climatic history across europe and the mediterranean abstract a small stalagmite from cova da arcoia in the serra do courel of northwestern spain provides a record both of general climate change across the holocene and of shorter term shifts between wetter and drier conditions nineteen u series dates from 9 3 ka to the present provide a chronology of the stalagmite with uncertainties of commonly only decades and at the most only 200 years these dates constrain the age of 18 petrographic surfaces that are of two types one type e inferred to result from dissolution during enhanced flow of water and the other type l inferred to result from lesser flow aragonite is more abundant in the earlier parts of the stalagmite and calcite is more abundant in the later part values of 13 c range from 5 6 to 1 3 relative to vpdb but are greatest beneath type l surfaces values of 18 o range from 5 4 to 4 4 relative to vpdb and have a weak but statistically significant correlation with 13 c greater abundance of aragonite greater values of 13 c and lesser frequency of type e surfaces early in the stalagmite suggest a drier and perhaps warmer early to middle holocene whereas greater abundance of calcite and frequent type e surfaces higher in the stalagmite suggest wetter conditions later in the holocene 18 o data are most compatible with this general conclusion however a prominent type e surface records the 8 2 ka event as an isolated wetter episode in the otherwise dry early holocene much of the stalagmite s aragonite and calcite suggests normal stalagmite growth in moderate climatic conditions however the near or complete cessation of growth at type l surfaces and greater 13 c greater 18 o and lesser fluorescence of aragonite beneath those surfaces combine to suggest at least six century scale episodes of strikingly dry conditions on the other hand evidence of dissolutional erosion at type e surfaces suggests at least ten distinct episodes of much wetter conditions these combine to suggest highly variable climate across the holocene at the scale of decades to a few centuries the record from this stalagmite is similar to records from greenland ice cores and from pollen and or stalagmite records from france northernmost spain and more broadly from northern or atlantic facing europe in contrast it suggests trends nearly opposite those in records from eastern and southern spain suggesting that the serra do courel is north of but perhaps not far from the boundary between atlantic and mediterranean regions of holocene climate trends in the iberian peninsula that general antiphasal relationship between northwestern spain and regions to the south and east extends to the specific observation that four of the most pronounced wetter events in the stalagmite s record coincide with periods of widespread drought and or cultural collapse in the mediterranean and middle east

growing global copper resources reserves and production discovery is not the only control on supply copper is vital to modem life and has an often irreplaceable role in everyday infrastructure and technology i however while the planet s cu endowment is finite global cu production continued to increase over the past century a growth that has been matched by significant growth in estimated cu mineral reserves and mineral resources here we present a study of 2015 global cu resources and reserves updated from a previous paper mudd et al 2013a that outlined global cu resources for 2010 the 2015 global cu resource database consists of 2 301 deposits of which 1 284 have code based resources and 1 017 have noncode based resources with a further 403 of these projects having code based reserves and a further four having noncode based reserves all mineral deposit types within the database have recorded an increase in cu resources between 2010 and 2015 except one although grades are often similar or slightly lower by similar to 5 or are significantly lower depending on the mineral deposit type considered porphyry deposits still dominate global cu resources and reserves containing similar to 75 of the contained cu in our database equally unsurprisingly chile dominates global cu resources and reserves followed by the united states and peru the resources within the database contain some 3 034 7 million tonnes k m 0 of cu up from the 1 861 3 mt reported in our 2010 study plus we report 640 9 m t of cu contained in reserves included in resources this is a significant increase even if all noncode based resources were removed i e 2 489 4 mt cu in code based projects there are three main reasons for this increase first this study is more comprehensive with an increase in deposit numbers 730 vs 2 301 second there have been new discoveries made or rather resources outlined between 2010 and 2015 third a significant proportion of resources within the 2010 study have grown in size by a mean value of 13 often coincident with significan

an optimized scheme of lettered marine isotope substages for the last 1 0 million years and the climatostratigraphic nature of isotope stages and substages a complete and optimized scheme of lettered marine isotope substages spanning the last 1 0 million years is proposed lettered substages for marine isotope stage mis 5 were explicitly defined by shackleton 1969 but analogous substages before or after mis 5 have not been coherently defined short term discrete events in the isotopic record were defined in the 1980s and given decimal style numbers rather than letters but unlike substages they were neither intended nor suited to identify contiguous intervals of time substages for time outside mis 5 have been lettered or in some cases numbered piecemeal and with conflicting designations we therefore propose a system of lettered substages that is complete without missing substages and optimized to match previous published usage to the maximum extent possible our goal is to provide order and unity to a taxonomy and nomenclature that has developed ad hoc and somewhat chaotically over the decades our system is defined relative to the lr04 stack of marine benthic oxygen isotope records and thus it is grounded in a continuous record responsive largely to changes in ice volume that are inherently global this system is intended specifically for marine oxygen isotope stages but it has relevance also for oxygen isotope stages recognized in time series of non marine oxygen isotope data and more generally for climatic stages which are recognized in time series of non isotopic as well as isotopic data the terms stage and substage in this context are best considered to represent climatostratigraphic units and thus climatic stages and climatic substages because they are recognized from geochemical and sedimentary responses to climate change that may not have been synchronous at global scale

climate and vegetation changes 180 000 to 345 000 years ago recorded in a deep sea core off portugal a new high resolution combined marine proxy pollen sequence from the portuguese margin md01 2443 enables direct comparison of ocean and ice volume changes with vegetation development in south west iberia during marine isotope stages mis 7 8 and 9 changes in sea surface conditions on both orbital and millennial time scales are closely mirrored by forest extent indicating a coherence of climate variability between the north atlantic and south west iberia deglacial warming at the start of mis 7 and 9 was interrupted by incursions of subpolar water masses at the site accompanied by reversals in tree population expansion during mis 7e and 9e the close relationship in timing and amplitude between vegetation and offshore conditions broke down early forest collapse points to pronounced cooling and aridification on land which although not accompanied by a change in water masses at the portuguese margin appears to have coincided with abrupt decreases in atmospheric methane concentration recorded in antarctic ice cores the most extreme glacial conditions of mis 8 occurred during the early part followed by an interval of warmer conditions and tree population expansion similar to 263 ka this has sometimes been considered as indicating an early deglaciation but the data presented here show that it was distinct from termination iii which occurred later in line with milankovitch forcing a sub orbital oscillation in both isotopic and pollen records is observed at the end of mis 7 ca 184 ka which appears to be coeval with a recently identified sea level high stand c 2006 elsevier b v all rights reserved

trace elements in holocene sediments of the southern donana national park sw spain historical pollution and applications the multidisciplinary analysis of core sediments from donana national park south spain permits to delimitate both the paleoenvironmental changes and the geochemical evolution of this area during the holocene in a first phase 10 6 5 kyr cal this area was occupied by freshwater brackish marshes with periodical alternation of dry periods and humid intervals in a second phase these marshes were inundated during the flandrian transgression 6 5 kyr cal with the deposition of bioclastic sands the third phase 6 5 3 6 kyr cal is characterized by the transition to an old lagoon with unpolluted bottom sediments the geochemical concentrations of these clayey sediments can be used as a geochemical background for present day and future environmental evaluations of this area in the following 600 years approximately two tsunamis caused the partial infilling of this area with bioclastic marine sediments in the interval comprised between these two tsunamis this lagoon was polluted with heavy metals derived from historical mining activities this environmental contamination represents one of the oldest evidences of mining pollution in the world 3 kyr cal bp

last interglacial climates the last interglacial commonly understood as an interval with climate as warm or warmer than today is represented by marine isotope stage mis 5e which is a proxy record of low global ice volume and high sea level it is arbitrarily dated to begin at approximately 130 000 yr b p and end at 116 000 yr b p with the onset of the early glacial unit mis 5d the age of the stage is determined by correlation to uranium thorium dates of raised coral reefs the most detailed proxy record of interglacial climate is found in the vostok ice core where the temperature reached current levels 132 000 yr ago and continued rising for another two millennia approximately 127 000 yr ago the eemian mixed forests were established in europe they developed through a characteristic succession of tree species probably surviving well into the early glacial stage in southern parts of europe after ca 115 000 yr ago open vegetation replaced forests in northwestern europe and the proportion of conifers increased significantly farther south air temperature at vostok dropped sharply pulses of cold water affected the northern north atlantic already in late mis 5e but the central north atlantic remained warm throughout most of mis 5d model results show that the sea surface in the eastern tropical pacific warmed when the ice grew and sea level dropped the essentially interglacial conditions in southwestern europe remained unaffected by ice buildup until late mis 5d when the forests disappeared abruptly and cold water invaded the central north atlantic ca 107 000 yr ago

a 120 yr record of widespread contamination from mining of the iberian pyrite belt a metal enriched seawater plume entering the western mediterranean sea through the strait of gibraltar originates 300 km to the west in the rio tinto estuary of southwestern spain mining of rio tinto ore one of the largest metal rich sulfide deposits in the world started well before roman times contemporary rio tinto waters draining the region are highly acidic ph 2 5 with dissolved cadmium zinc and copper concentrations 10 5 10 6 times higher than in uncontaminated surface water of the gulf of cadiz two dated sediment cores from the spanish continental shelf show that metal inputs to the region increased with the onset of intensive mining activities during the second half of the 19th century although the impact of mining may have decreased over the past few decades the tinto river and estuary remain highly contaminated

ice sheet collapse following a prolonged period of stable sea level during the last interglacial sea level during the last interglacial period reached a peak of between 5 and 9 m above the present day level a detailed reconstruction of sea level and isostatic rebound from western australia indicates a prolonged period of sea level stability at 3 4 m above present followed by an abrupt sea level rise of 5 6 m

eemian interglacial reconstructed from a greenland folded ice core efforts to extract a greenland ice core with a complete record of the eemian interglacial 130 000 to 115 000 years ago have until now been unsuccessful the response of the greenland ice sheet to the warmer than present climate of the eemian has thus remained unclear here we present the new north greenland eemian ice drilling neem ice core and show only a modest ice sheet response to the strong warming in the early eemian we reconstructed the eemian record from folded ice using globally homogeneous parameters known from dated greenland and antarctic ice core records on the basis of water stable isotopes neem surface temperatures after the onset of the eemian 126 000 years ago peaked at 8 4 degrees celsius above the mean of the past millennium followed by a gradual cooling that was probably driven by the decreasing summer insolation between 128 000 and 122 000 years ago the thickness of the northwest greenland ice sheet decreased by 400 250 metres reaching surface elevations 122 000 years ago of 130 300 metres lower than the present extensive surface melt occurred at the neem site during the eemian a phenomenon witnessed when melt layers formed again at neem during the exceptional heat of july 2012 with additional warming surface melt might become more common in the future

abrupt onset and termination of the african humid period rapid climate responses to gradual insolation forcing a detailed ca 100 yr resolution and well dated 18 ams 14 c dates to 23 cal ka bp record of latest pleistocene holocene variations in terrigenous eolian sediment deposition at odp site 658c off cap blanc mauritania documents very abrupt large scale changes in subtropical north african climate the terrigenous record exhibits a well defined period of low influx between 14 8 and 5 5 cal ka bp associated with the african humid period when the sahara was nearly completely vegetated and supported numerous perennial lakes an arid interval corresponding to the younger dryas chronozone punctuates this humid period the african humid period has been attributed to a strengthening of the african monsoon due to gradual orbital increases in summer season insolation however the onset and termination of this humid period were very abrupt occurring within decades to centuries both transitions occurred when summer season insolation crossed a nearly identical threshold value which was 4 2 greater than present these abrupt climate responses to gradual insolation forcing require strongly non linear feedback processes and current coupled climate model studies invoke vegetation and ocean temperature feedbacks as candidate mechanisms for the non linear climate sensitivity the african monsoon climate system is thus a low latitude corollary to the bi stable behavior of high latitude deep ocean thermohaline circulation which is similarly capable of rapid and large amplitude climate transitions

exploring holocene continentality changes in fennoscandia using present and past tree distributions with global warming the distribution of warmth through the year is likely to change in the future and comparable changes may have occurred over the course of the holocene its effect on vegetation composition and species distribution can be compared to that of a continental versus an oceanic climate the distribution of five major tree species along a continentality gradient was studied in fennoscandia based on distribution maps and on their proportions of pollen in surface sediment samples both analyses indicate that the five arboreal species show similar patterns of response to a continentality index in the order ulmus glabra corylus avellana quercus robur tilia cordata and picea abies from the most oceanic to most continental continentality growing degree days above 5 degrees c and january temperature were reconstructed quantitatively from four pollen diagrams using transfer functions based on a combined fennoscandian pollen surface sample data set quantitative reconstructions indicate that the climate in fennoscandia has become increasingly more continental over the last 7000 years and this is largely an effect of winter cooling early holocene vegetation composition has poor analogues to the present vegetation in fennoscandia which hampers quantitative reconstructions qualitative reconstructions suggest that the early holocene in fennoscandia was the most oceanic period but probably with a high variability in temperature c 2008 elsevier ltd all rights reserved

characterization of acid mine drainage sources in the iberian pyrite belt base methodology for quantifying affected areas and for environmental management the present work aims to propose a methodology for quantifying the sources of acid mine drainage amd and to characterize the magnitude of the affected areas in the iberian pyrite belt sw spain such an approach allows the creation of a support tool for managing land and natural resources valorization which may be easily applied in similar mining regions the motivation and usefulness of this work can be realized by focusing on two main emerging strategic issues 1 water resources management with the example of alcolea dam that will receive water from affected areas in the iberian pyrite belt and 2 mineral resources valorization especially regarding copper exploration due to increasing market prices the used methodology included the following general steps it started with an inventory of the mines in the iberian pyrite belt followed by field cartography campaigns and finally the quantification of affected areas and contaminant discharges the results of the present work serve to confirm and quantify the magnitude of the amd pollution in the pyrite belt a total affected area of about 4 847 ha was estimated taking into account this figure and combining it with the annual average precipitation 650 l m2 results in an estimation of 31 503 680 m3 year of discharging water affected by the presence of sulphides in this scenario a total annual contribution of 260 056 tonnes year was obtained for sulphates which means more than 712 tonnes a day in the case of arsenic a toxic element the total annual contribution is more than 20 tonnes or close to 55 kg day regarding copper this economically interesting metal translates into total contributions of 10 364 tonnes year in the generating medium this gave more than 28 tonnes day which today sits at 8 200 dollars tonne this result suggests that solutions aimed at recovering this resource should be searched it may represent a financial return at the same time that it would mean overcome environmental liabilities

evolution of the pollution in the piedras river natural site gulf of cadiz southern spain during the holocene the piedras river marshland and el rompido spit bar is a natural site in close proximity to two of the most polluted rivers in the world the tinto and odiel rivers the aim of this study is to determine the degree of contamination of this natural site using a variety of pollution indices at this site the holocene infilling sequence is recorded and applied to a study of the pollution history and the possible impacts of human activity the depositional history of the piedras river estuary during the holocene recorded open marine conditions at ca 6500 calbp when sea level was at its holocene maximum to study the pollution of the estuary during the holocene catchment background geochemistry was established using samples that pre date human activity agriculture and mining additionally the sedimentary environment was reconstructed throughout the holocene comparison of pollution levels is interpreted to be more reliable if the sedimentary environment has remained similar throughout the depositional record results show that despite being located nearby very polluted estuaries the piedras river marshland contains unpolluted sediments mainly because of the small catchment area relative to that of neighbouring more polluted rivers and thus has not been affected by human activity such as mining

high precision and high resolution carbonate 230th dating by mc icp ms with sem protocols abstract to facilitate the measurement of u th isotopic compositions suitable for high precision and high resolution 230th dating of coral and speleothem carbonates secondary electron multiplier sem protocol techniques for multicollector inductively coupled plasma mass spectrometry mc icp ms have been developed the instrumental sensitivities are 1 2 with a precision of 1 2 2 for abundance determination of 50 200 fg 234u 1 4 ng 238u or 230th this method features chemistry refinements improvements to procedural and instrumental blanks spectral inference reductions and careful consideration of non linear sem behavior measurement consistency of this mc icp ms combined with previous mass spectrometric results on u th standards and a variety of carbonates demonstrates the validity of the sem protocol method for fossil corals a routine u th isotopic determination at permil level precision requires only 10 50 mg of carbonate as little as 200 mg of young coral with an age of less than 20 yr can be dated with a precision of 0 3 0 8 yr about 20 200 mg speleothem samples with sub ppm to ppm u are required to earn a 5 precision on ages from 5 to 100 kyr requirement of small sample size 10 100s mg carbonate can permit high temporal resolution to date speleothems with slow growth rates i e 1 10 mm kyr this high precision 230th chronology is critical to accurately establish age models date events and splice geochemical proxy time series records from multiple samples in the fields of paleoclimatology and paleoceanography the u th isotopic determination techniques described here can also be applied to different environmental samples such as waters rocks and sediments

the las cruces deposit iberian pyrite belt spain abstract the las cruces deposit is located at the eastern margin of the iberian pyrite belt ipb beneath the neogene quaternary deposits of the guadalquivir basin these sediments covered and preserved the supergene profile somewhat after its generation until its recent discovering for this reason the las cruces ore deposits together with lagoa salgada in portugal are the only known deposits in the ipb that preserve the entire weathering profile including both the gossan and the enrichment zone in that sense the present study provides new data on the ipb ore deposits and their post palaeozoic evolution the primary mineralization consists of massive and semi massive polymetallic sulfides overlaying a cupriferous and pyritic stockwork the supergene enrichment extends from the primary zone to gossan and consists of a thick cementation zone characterized by intense replacement of part of the primary sulfides by cu rich supergene sulfides at present the only economic resource of las cruces is the cementation zone with initial reserves of 17 6 mt 6 2 cu but the orebody also includes significant contents of cu and zn within the primary mineralization and au ag and pb in the gossan mineralogical and geochemical data confirm that the primary mineralization at las cruces resembles other ipb deposits in terms of distribution and evolution however the gossan and cementation zone show an uncommon evolution for this kind of supergene profile the major singularity that makes the las cruces supergene mineralisation noticeably different from others in the ipb or elsewhere resides in its unusual mineralogical composition mostly comprised of newly formed siderite calcite fe sulfides and galena the genetic model proposed for the las cruces deposit includes three main stages 1 ore genesis and evolution of primary mineralization which seems to be comparable to other ipb deposits 2 genesis of cu rich secondary mineralization and gossan by weathering after miocene exhumation of the upper part of the massive sulfide deposit under oxidizing and acidic conditions and 3 late evolution of supergene profile below the carbonated rich sediments of the guadalquivir basin with the subsequent change in the redox conditions due to water rock interaction between the supergene profile and basinal fluids

sea level history during the last interglacial complex on san nicolas island california implications for glacial isostatic adjustment processes paleozoogeography and tectonics abstract san nicolas island california has one of the best records of fossiliferous quaternary marine terraces in north america with at least fourteen terraces rising to an elevation of 270 m above present day sea level in our studies of the lowest terraces we identified platforms at 38 36 m terrace 2a 33 28 m terrace 2b and 13 8 m terrace 1 uranium series dating of solitary corals from these terraces yields three clusters of ages 120 ka on terrace 2a marine isotope stage mis 5 5 120 and 100 ka on terrace 2b mis 5 5 and 5 3 and 80 ka mis 5 1 on terrace 1 we conclude that corals on terrace 2b that date to 120 ka were reworked from a formerly broader terrace 2a during the 100 ka sea stand fossil faunas differ on the three terraces isolated fragments of terrace 2a have a fauna similar to that of modern waters surrounding san nicolas island a mix of extralimital southern and extralimital northern species is found on terrace 2b and extralimital northern species are on terrace 1 on terrace 2b with its mixed faunas extralimital southern species indicating warmer than present waters are interpreted to be from the 120 ka high sea stand reworked from terrace 2a the extralimital northern species on terrace 2b indicating cooler than present waters are interpreted to be from the 100 ka sea stand the abundant extralimital northern species on terrace 1 indicate cooler than present waters at 80 ka using the highest elevations of the 120 ka platform of terrace 2a and assuming a paleo sea level of 6 m based on previous studies san nicolas island has experienced late quaternary uplift rates of 0 25 0 27 m ka these uplift rates along with shoreline angle elevations and ages of terrace 2b 100 ka and terrace 1 80 ka yield relative local paleo sea level elevations of 2 to 6 m for the 100 ka sea stand and 11 to 12 m for the 80 ka sea stand these estimates are significantly higher than those reported for the 100 ka and 80 ka sea stands on new guinea and barbados numerical models of the glacial isostatic adjustment gia process presented here demonstrate that these differences in the high stands are expected given the variable geographic distances between the sites and the former laurentide and cordilleran ice sheets moreover the numerical results show that the absolute and differential elevations of the observed high stands provide a potentially important constraint on ice volumes during this time interval and on earth structure

a petrographic and geochemical record of climate change over the last 4600years from a northern namibia stalagmite with evidence of abruptly wetter climate at the beginning of southern africa s iron age abstract stalagmite dp1 a speleothem 1 6 m in length from dante cave in northeastern namibia provides a paleoclimate record of a gradual transition from wetter to drier conditions from 4 6 to 3 3 ka bp a variable but pronounced dry period from 3 3 to 1 8 ka and a wetter but variable period from 1 8 ka to the present this record is based on 30 u th radiometric dates and their resulting calculated growth rates and on c and o stable isotope data relative proportions of aragonite and calcite in layers measurements of stalagmite width along layers and observation of petrographic surfaces suggestive of changes from drier to wetter conditions and vice versa the stalagmite s first deposition which seemingly followed conditions too wet for deposition coincided with desiccation in the sahara and the end of the african humid period there gradual drying continued and led to a sustained very dry period from 3322 11 to 1786 10 bp a 2 3 ka bp dry period that dry period began and ended abruptly the abrupt transition from drier to wetter conditions at 1 8 ka coincides with the beginning of the iron age in southern africa suggesting that wetter conditions facilitated migrations and or changes in food production that may have contributed to a transition in human technologies and lifestyles this transition is coeval with transitions to colder conditions in ice core records from greenland and antarctica the dp1 record suggests considerable change over the past 1800 years with at least three wet dry cycles the wettest conditions may have occurred relatively recently between 230 and 100 bp a d 1720 and 1850 so that early european explorers may have seen and or heard reports of conditions among the wettest during the later holocene in southern africa

holocene vegetation zonation in the eastern sahara recent discoveries of fossil bearing holocene lake sediments from the eastern sahara have brought further confirmation and detail to earlier indirect evidence that a major pluvial episode occurred between 9 500 and 4 500 yr bp1 3 the botanical results mainly palynological show that savanna and desert grassland occupied regions that today are plantless hyperarid deserts we present here the first evidence from the entire saharan region of a latitudinal zonation of holocene vegetation extending across a 500 km wide belt in north west sudan we have completed detailed pollen analyses of three of the several sites discovered so far and the salient features from two the northernmost and the southernmost are presented here to demonstrate a steep gradient of past vegetative cover

acid mine drainage and acid rock drainage processes in the environment of herrerias mine iberian pyrite belt huelva spain and impact on the andevalo dam the present work describes the process of acid water discharge into the andevalo dam iberian pyrite belt huelva spain starting from the interpretation of rainfall data and chemical analyses regarding ph conductivity metal and sulphate content in water from a time series corresponding to the sampling of two confluent channels that discharge water into the referred dam statistical data treatment allows us to conclude the existence of acid mine drainage processes in the chorrito stream which are translated into very low ph values and high sulphate and metal concentrations in the water coming from herrerias mine on the other hand the higuereta stream shows for the same parameters much lower values that can be interpreted as the channel response to acid rock drainage processes in its drainage basin induced by the rocky outcrops of the iberian pyrite belt

lead pollution resulting from roman gold extraction in northwestern spain roman mining and metallurgy left a detectable signal of lead pollution throughout europe northern africa and the middle east las medulas in northwestern iberia was the largest roman gold mine

peat formation concentrates arsenic within sediment deposits of the mekong delta abstract mekong river delta sediment bears arsenic that has been released to groundwater under anaerobic conditions over the past several thousand years the oxidation state speciation and distribution of arsenic and the associated iron bearing phases are crucial determinants of as reactivity in sediments peat from buried mangrove swamps in particular may be an important host source or sink of arsenic in the mekong delta the total concentration speciation and reactivity of arsenic and iron were examined in sediments in a mekong delta wetland by x ray fluorescence spectrometry xrf x ray absorption spectroscopy xas and selective chemical extractions total solid phase arsenic concentrations in a peat layer at a depth of 6 m below ground increased 10 fold relative to the overlying sediment extended x ray absorption fine structure exafs spectroscopy revealed that arsenic in the peat was predominantly in the form of arsenian pyrite arsenic speciation in the peat was examined further at the micron scale using xrf and x ray absorption near edge structure xanes spectroscopy coupled with principal component analysis the multiple energy xrf mapping and xanes routine was repeated for both iron and sulfur phase analyses our xrf xanes analyses confirm arsenic association with pyrite a less reactive host phase than iron hydr oxides under anaerobic conditions the arsenian pyrite likely formed upon deposition formation of the peat in a past estuarine environment 5 5 ka bp a process that is not expected under current geochemical conditions presently arsenian pyrite is neither a detectable source nor a sink for aqueous arsenic in our sediment profile and under present geochemical conditions represents a stable host of as under the reducing aquifer conditions of the mekong delta furthermore organic carbon within the peat is unable to fuel fe iii reduction as noted by the persistence of goethite which can be reduced microbially with the addition of glucose

unravelling the holocene environmental history of south western iberia through a palynological study of lake medina sediments lake medina is a small shallow and endorheic salt lake sensitive to climate variation in south western spain close to cadiz in western andalusia it is located in an evaporitic and karstic enviro

4 500 year old mining pollution in southwestern spain long term implications for modern mining pollution the tinto river drains the rio tinto mining district which comprises the world s largest known massive sulfide deposits these orebodies have been mined from the third millenium bc to the present the tinto river is strongly acidic ph 1 5 2 5 during flood events it transports a sandy material including abundant detrital pyrite grains a core drilled in the holocene sediments of the tinto estuary allows for investigation of recent and historical mining pollution two anomalous horizons have been recognized 0 1 3 m 3 4 m both are characterized by very high metal content 100 times over the background and by the presence of abundant clastic pyrite grains the metal association pb ba as cu zn sn tl cd ag hg au is typical of that of the rio tinto pyritic ore the upper horizon corresponds to the modern mining activity the lower horizon has been dated at 2530 bc 14c ams calibrated age we show here that active mining occurred early copper age in the rio tinto area resulting in a watershed scale metal contamination we also show that anthropogenic input of metals may be accumulated and immobilized during thousands of years in estuarine sediments

contrasting intrainterstadial climatic evolution between high and middle north atlantic latitudes a close up of greenland interstadials 8 and 12 1 three highly resolved pollen and sea surface temperature records from the iberian margin 36 42 n reveal the local evolution of vegetation and climate associated with the rapid climatic variability of marine isotope stage 3 the comparison of the climate at these midlatitudes with d and d excess from greenland ice cores shows that the north south climatic gradient underwent strong variations during the long greenland interstadials gis 8 and 12 after the northern hemispheric rapid warming at the greenland stadial gs gi transition the trend during the first part of the gi is a greenland cooling and an iberian warming this increase of the north atlantic climatic gradient led to moisture transportation to greenland from midlatitudes lightest d excess and to a drying episode in iberia the subsequent temperature decrease in greenland and iberia associated with the precipitation increase in the latter region occurred when the major source of greenland precipitation shifted to lower latitudes d excess increase

geological record of an acidic environment driven by iron hydrochemistry the tinto river system 1 the existence of possible hematitic strata on the surface of mars demands a search for terrestrial analogues formed in unusual environments this will help us to recognize and interpret environmental and perhaps biological signatures preserved in mars hematites such an analogue would allow us to establish valid reference systems based on geomicrobial and biogeochemical signatures two different aspects place the tinto river inside the boundaries of a natural extreme system its high level of biological diversity and the presence of fluvial rocks formed in the same acidic conditions as in the modern system which could predate the tertiary study of both the modern system and the ancient system is necessary to understand the formation of biosignatures a chemolithotrophic community that biooxidizes the iberian pyritic belt acidifying water ph between 0 9 and 3 0 and favoring high concentrations of ferric iron in solution up to 20 g l 1 maintains this iron driven system in spite of these extreme conditions high microbial diversity was found its acidic bacteria archaea and eukarya constitute a complex community supported by algal biomass in highly stable hydrochemical conditions which are achieved through iron buffering the ph is maintained at constant low levels even at very high water dilution in these conditions iron minerals as oxyhydroxides hydroxides and sulfates are formed the modern and recent parageneses contrast with the ancient tinto river terrace mineral associations which show dehydrated and desulfated iron oxides if this dehydration process is considered these tinto river ironstones may be a key for knowing some aquatic habitats which may have hosted a part of the early mars biosphere

the impact of tailings dam spills and clean up operations on sediment and water quality in river systems the rios agrio guadiamar aznalcollar spain the aznalcollar tailings dam at boliden apirsa s aznalcollar los frailes ag cu pb zn mine 45 km west of seville spain was breached on 25 april 1998 flooding approximately 4600 hectares of land along the rios agrio and guadiamar with approximately 5 5 million m3 of acidic water and 1 3 106 m3 of heavy metal bearing tailings most of the deposited tailings and approximately 4 7 106 m3 of contaminated soils were removed to the aznalcollar open pit during clean up work undertaken immediately after the spill until january 1999 detailed geomorphological and geochemical surveys of the post clean up channel floodplain and valley floor and sediment and water sampling were carried out in january and may 1999 at 6 reaches representative of the types of river channel and floodplain environments in the rio guadiamar catchment affected by the spill the collected data show that the clean up operations removed enough spill deposited sediment to achieve pre spill metal ag as cd cu pb sb tl zn concentrations in surface sediment these concentrations however are still elevated above pre mining concentrations and emphasise that mining continues to contaminate the agrio guadiamar river system dilution by relatively uncontaminated sediment appears to reduce metal concentrations downstream but increases in metal and as concentrations occur downstream presumably as a result of factors such as sewage and agriculture river water samples collected in may 1999 have significantly greater dissolved concentrations of metals and as than those from january 1999 probably due to greater sulphide oxidation from residual tailings with concomitant release of metals in the warmer early summer months these concentrations are reduced downstream probably by a combination of dilution and removal of metals by mineral precipitation single chemical extractions de ionised water cacl2 0 01 mol l 1 ch3coonh4 1 m ch3coona 1 m and ammonium oxalate 0 2 m on alluvial samples from reaches 1 and 6 the tailings pre spill alluvium and marl have shown that the order of sediment borne contaminant mobility is generally zn cd cu pb as pb and as are relatively immobile except possibly under reducing conditions much of the highly contaminated sediment remaining in the floodplain and channel still contains a large proportion of tailings related sulphide minerals which are potentially reactive and may continue to release contaminants to the agrio guadiamar river system our work emphasises the need for pre mining geomorphological and geochemical data and an assessment of potential contributions of contaminants to river systems from other non mining sources

the δ18o record along the greenland ice core project deep ice core and the problem of possible eemian climatic instability over 70 000 samples from the 3029 m long greenland ice core project grip ice core drilled on the top of the greenland ice sheet summit have been analyzed for 8o a highly detailed and continuous 8o profile has thus been obtained and is discussed in terms of past temperatures in greenland we also discuss a three core stacked annual 8o profile for the past 917 years the short term 50 years variability of the annual 8o signal is found to be 1 in the holocene and estimates for the coldest parts of the last glacial are 3 or higher these data also provide insights into possible disturbances of the stratigraphic layering in the core which seems to be sound down to the onset of the eemian spectral analysis of highly detailed sequences of the profile helps determine the smoothing of the 8o signal which for the holocene ice is found to be considerably stronger than expected we suggest this is due to a process involving diffusion of water molecules along crystal boundaries in the recrystallizing ice matrix deconvolution techniques were employed for restoring with great confidence the highly attenuated annual 8o signal in the holocene we confirm earlier findings of dramatic temperature changes in greenland during the last glacial cycle abrupt and strong climatic shifts are also found within the eem sangamon interglaciation which is normally recorded as a period of warm and stable climate in lower latitudes the stratigraphic continuity of the eemian layers is consequently discussed in section 3 of this paper in terms of all pertinent data which we are not able to reconcile

recent developments in the study of the upper paleolithic of vasco cantabrian spain abstract this is an updated review of recent post 2004 developments in the study of the rich upper paleolithic 40 10 uncal ka record from the spanish wing of the classic franco cantabrian culture area composed of the provinces of asturias cantabria vizcaya guipuzcoa and northern navarra numerous new ongoing excavations radiometric dating assays paleoenvironmental artifact and faunal analyses are summarized here and their implications for understanding the middle upper paleolithic transition and the succession of anatomically modern human adaptations in this narrow mid latitude strip bounded to the north by the gulf of gascony and to the south by the cantabrian cordillera constants in this record are the balance between regionally distinctive characteristics in terms of ecology faunas artifacts subsistence and art and the reality of connections to the upper paleolithic cultures of france and the rest of iberia the role of the region as a glacial age refugium the fundamental continuity of human settlement with movements between the coastal lowlands and the adjacent montane interior the intensification of subsistence through situational specialization and overall diversification with periods of intensive demographic and environmental stress underlying facts of lithology and the differential availability and utilization of flints and non flint raw materials for different types of tools the demographically critical role of intra and extra regional social networks within the context of valley defined local band territories the review proceeds along the lines of traditionally defined cultural traditions aurignacian sensu lato gravettian solultrean magdalenian and azilian although it is recognized that these are archeological constructs and that there is both considerable variability within each of these concepts and a considerable degree of similarity cross cutting all of them

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

historical signature of roman mining activities in the bidasoa estuary basque country northern spain an integrated micropalaeontological geochemical and archaeological approach abstract this work presents an integrated micropalaeontological foraminiferal content geochemical pb zn cu ni cr and al pb isotope ratios radiocarbon dating and archaeological approach to the environmental impact caused by roman mining in the bidasoa estuary northern spain sediments collected in the ancient roman port of irun represent a typical infilling sequence reflecting a progressive isolation from the estuarine environment they exhibit elevated contents of pb clearly higher than those recommended nowadays for acceptable sediment quality isotope composition confirms exploitation of local galenas as the main source for this metal results from a borehole 25 m long reveal that pb pollution extended also to the adjacent estuarine area the beginning of roman mining activities is recorded by a marked increase in pb concentrations however the maximum value appears later in time after 660 cal ad although this enrichment could be related to the reworking upstreams of previously polluted materials recently obtained archaeological data suggest that episodes of historically non documented mining activities could have taken place in the surrounding area after roman times

temperature trends during the present and last interglacial periods a multi model data comparison though primarily driven by insolation changes associated with well known variations in earth s astronomical parameters the response of the climate system during interglacials includes a diversity of feedbacks involving the atmosphere ocean sea ice vegetation and land ice a thorough multi model data comparison is essential to assess the ability of climate models to resolve interglacial temperature trends and to help in understanding the recorded climatic signal and the underlying climate dynamics we present the first multi model data comparison of transient millennial scale temperature changes through two intervals of the present interglacial pig 8 1 2 ka and the last interglacial lig 123 116 2 ka periods we include temperature trends simulated by 9 different climate models alkenone based temperature reconstructions from 117 globally distributed locations about 45 of them within the lig and 12 ice core based temperature trends from greenland and antarctica 50 of them within the lig the definitions of these specific interglacial intervals enable a consistent inter comparison of the two intervals because both are characterised by minor changes in atmospheric greenhouse gas concentrations and more importantly by insolation trends that show clear similarities our analysis shows that in general the reconstructed pig and lig northern hemisphere mid to high latitude cooling compares well with multi model mean temperature trends for the warmest months and that these cooling trends reflect a linear response to the warmest month insolation decrease over the interglacial intervals the most notable exception is the strong lig cooling trend reconstructed from greenland ice cores that is not simulated by any of the models a striking model data mismatch is found for both the pig and the lig over large parts of the mid to high latitudes of the southern hemisphere where the data depicts negative temperature trends that are not in agreement with near zero trends in the simulations in this area the positive local summer insolation trend is counteracted in climate models by an enhancement of the southern ocean summer sea ice cover and or an increase in southern ocean upwelling if the general picture emerging from reconstructions is realistic then the model data mismatch in mid and high southern hemisphere latitudes implies that none of the models is able to resolve the correct balance of these feedbacks or alternatively that interglacial southern hemisphere temperature trends are driven by mechanisms which are not included in the transient simulations such as changes in the antarctic ice sheet or meltwater induced changes in the overturning circulation

sea level rise and anthropogenic activities recorded in the late pleistocene holocene sedimentary infill of the guadiana estuary sw iberia abstract this study reviews data on sea level rise during the last 13000 yr cal bp 13 kyr as recorded in the estuarine sediments of the guadiana river se portugal sw spain we combined new data from a 63 m long borehole drilled through the entire postglacial sedimentary sequence with information on five previously studied cores by integrating sedimentological geochemical and palaeontological proxies we were able to make a palaeoenvironmental reconstruction of the guadiana terminal palaeovalley during the last 13 kyr and propose a curve of sea level rise for the sw iberian atlantic margin our foraminifera based palaeoecological reconstruction anchored to a 14 c age model reveals rapid sea level rise from 13 kyr interrupted during the younger dryas and resuming ca 11 5 kyr the pace of marine transgression slackened ca 7 5 kyr and since then has progressed upwards at a rate of 1 2 mm yr 1 holocene anthropocene sediments from two boreholes were also analysed to assess the timing levels and sources of trace metals produced by acid mine drainage from the iberian pyrite belt study of metal aluminium ratios through the profiles allowed background metal concentrations to be estimated from lithostratigraphic units older than ca 5 kyr i e unaffected by anthropogenic activities human activities are especially evident from 4 5 kyr the beginning of the copper age with anthropogenic sources of metal fluxes prevailing over natural sources especially pb co ni and mn and to a lesser extent zn cu and ni mining activities became particularly intensive between the late bronze age and the roman period 3 1 5 kyr when the highest metal enrichment factors were recorded ef pb 2 ef cd 10 ef cr 2 ef cu 3 ef zn 1 4 this study reveals the utility of postglacial sedimentary records for reconstructing historical changes in regional water sediment quality and separating natural and anthropogenic sources of geochemical contaminants

hydrochemical variations and contaminant load in the rio tinto spain during flood events summary the aim of this work is to study the hydrochemical variations during flood events in the rio tinto sw spain three separate rainfall flood events were monitored in october 2004 following the dry season in general concentrations markedly increased following the first event fe from 99 to 1130 mg l q max 0 78 m 3 s while dissolved loads peaked in the second event fe 7 5 kg s cu 0 83 kg s zn 0 82 kg s q max 77 m 3 s and discharge in the third event q max 127 m 3 s this pattern reflects a progressive depletion of metals and sulphate stored in the dry summer as soluble evaporitic salt minerals and concentrated pore fluids with dilution by freshwater becoming increasingly dominant as the month progressed variations in relative concentrations were attributed to oxyhydroxysulphate fe precipitation to relative changes in the sources of acid mine drainage e g salt minerals mine tunnels spoil heaps etc and to differences in the rainfall distributions along the catchment the contaminant load carried by the river during october 2004 was enormous totalling some 770 t of fe 420 t of al 100 t of cu 100 t of zn and 71 t of mn this represents the largest recorded example of this flush out process in an acid mine drainage setting approximately 1000 times more water and 140 8200 times more dissolved elements were carried by the river during october 2004 than during the dry low flow conditions of september 2004 highlighting the key role of flood events in the annual pollutant transport budget of semi arid and arid systems and the need to monitor these events in detail in order to accurately quantify pollutant transport

influence of eolian deposition and rainfall amounts on the u isotopic composition of soil water and soil minerals 230th u dating of secondary deposits such as speleothems and pedogenic carbonate and opal provides information about the original 234u 238u composition of the waters the minerals precipitated from as a result these types of deposits often display temporal variations in initial 234u 238u that could reflect environmental variability past variations in soil water 234u 238u may reflect changes in the flux of water through the soil weathering rates or dust inputs in order to evaluate these potential influences we analyzed modern soil water chemistry and u isotopic compositions of fluids and solids from three soil sequences in nevada modern soil pore waters from diamond valley newark valley and fish lake valley nevada show significant 234u 238u differences between sites as a result of differing soil parent material newark valley pore waters are more heavily influenced by carbonate weathering and display much more enriched 234u 238u values than diamond and fish lake valley pore waters which are dominated by silicate weathering newark valley and diamond valley although located very near to each other have significantly different pore water 234u 238u values suggesting that deposition of distantly sourced dust does not exert a dominant influence on pore water 234u 238u at these sites pore water 234u 238u values also vary systematically along a rainfall gradient at fish lake valley where sites with lower rainfall display higher soil water 234u 238u values the results of this modern soil water chemistry study were used to parameterize two models that investigate the relative influence of dust content recoil and weathering on pore water 234u 238u in the upper layer of the soil and at depth under changing infiltration rates these models suggest that while the composition of soluble dust entering a soil profile is an important consideration the pore water 234u 238u at depth and thus the initial 234u 238u of minerals that precipitate from pore waters should be highly sensitive to changes in the infiltration flux through the soils as infiltration flux is closely tied to rainfall the initial 234u 238u of soil minerals at these sites should provide information about past rainfall variability

palaeo climate reconstruction from stable isotope variations in speleothems a review abstract speleothems are now regarded as valuable archives of climatic conditions on the continents offering a number of advantages relative to other continental climate proxy recorders such as lake sediments and peat cores they are ideal materials for precise u series dating yielding ages in calendar years thereby circumventing the radiocarbon calibration problems associated with most other continental records stable isotope studies in speleothems have shifted away from attempting to provide palaeo temperature reconstructions to the attainable goal of providing precise estimates for the timing and duration of major o isotope defined climatic events characterised by high signal to noise ratios e g glacial interglacial transitions dansgaard oeschger oscillations the 8200 year event unlike the marine records speleothem data sets are not tuned and their independent chronology offers opportunities to critically assess leads and lags in the climate system that in turn can provide important insights into forcing and feedback mechanisms improved procedures for the extraction and measurement of stable isotope ratios in fluid inclusions trapped in speleothems are likely to provide in the near future a much enhanced basis for the quantitative interpretation of o isotope ratios in speleothem calcite the latter developments open up once again the tantalising prospect of palaeo temperature estimates but more importantly perhaps provide a direct test for a new generation of general circulation models whose hydrological cycles will incorporate the water isotopes the literature is reviewed briefly to provide for the reader a sense of the current state of the art and to provide some pointers for future research directions

paleoclimate variability during the blake geomagnetic excursion mis 5d deduced from a speleothem record abstract to evaluate possible connections between climate and the earth s magnetic field we examine paleoclimate proxies in a stalagmite pa 8 recording the blake excursion 112 116 4 ka from cobre cave n spain trace element 13 c 18 o 234 u fluorescent lamination growth rate and paleomagnetic records were synchronized using a floating lamina counted chronology constrained by u th dates providing a high resolution multi proxy paleoclimate record for mis 5d the alpine cave setting and the combination of proxies contributed to improve the confidence of the paleoclimatic interpretation periods of relatively warm and humid climate likely favored forest development and resulted in high speleothem growth rates arguably annual fluorescent laminae low 13 c and mg and increased sr and ba colder periods limited soil activity and drip water availability leading to reduced speleothem growth poor development of fluorescent lamination enhanced water rock interaction leading to increased mg 13 c and 234 u and episodic flooding in the coldest and driest period recorded evaporation caused simultaneous 18 o and 13 c enrichments and perturbed the trace element patterns the blake took place in a relatively warm interestadial at the inception of the last glacial period but during a global cooling trend recorded in pa 8 by an overall decrease of 18 o and growth rate and increasing mg that trend culminated in the cessation of growth between 112 and 101 ka likely due to the onset of local glaciation correlated with greenland stadial 25 that trend is consistent with a link between low geomagnetic intensity and climate cooling but it does not prove it shorter term changes in relative paleointensity rpi relate to climate changes recorded in pa 8 particularly a prominent rpi low from 114 5 to 113 ka coincident with a significant cooling indicated by all proxy records suggesting a link between geomagnetic intensity and climate at millennial time scales although the reliability of such inference is limited by the inferior resolution of the paleomagnetic data and a possible contamination of the rpi data by unaccounted changes in magnetite concentration the agreement of those data with the marine record of cosmogenic be suggests that the rpi record of pa 8 may reflect truly geomagnetic intensity variations

interaction between sedimentary processes historical pollution and microfauna in the tinto estuary sw spain the analysis of a short core collected in the tinto estuary sw spain permits to delimitate the influence of historical mining activities on sediments and microfauna foraminifera and ostracoda in very shallow palaeochannels of the middle estuary a first mining period 3 600 cal years bp caused high sediment pollution by cu with a significant diminution of the palaeontological record due to continuous acid mining drainage processes in this core the polluted levels derived from both roman extractions 2 000 1 900 years bp and the extensive mining activities between 1870 and 1935 have been eroded the 1 800 200 years bp period is characterized by a limited mining activity and an important improvement of this ecosystem in addition the effects of recent industrial wastes have been limited in this area

spatial distribution of major and trace elements in a mining dam sources and relationships among elements of environmental concern the concentration of major and trace elements have been determined in sediments samples taken from a mining dam located in the upper area of the tinto river basin sw spain this dam built to fulfil water needs for mining operations is now completed clogged by accumulation of fine sediments the results obtained for vertical and horizontal distribution of chemical elements showed highest average concentrations of fe and al both with 10 and s about 4 toxic elements such as as and pb occur also with high concentrations 2515 and 5172 mg kg respectively determination of enrichment factors ef showed that sediments are enriched in elements related with the massive sulphide ore bodies and subsequent acid mine drainage processes the elements pb and as are that of major environmental concern with enrichment factors higher than 10 application of cluster analysis put in evidence the main sources of elements allowing for the modelling of the origin of the accumulated matter therefore in addition to contributions from sulphide fe s and gangue al mg there are grouping of elements mobilized from phyllosilicates and feldspars e g ca and k as well as a specific group that reflects the geochemical affinity of rare earth elements in such acidic environment moreover the way how elements are grouped testify the heterogeneity of geological contributions as well as the mining cycles over 4000 years of mining history in this worldwide known river basin

geochemical signature as paleoenvironmental markers in holocene sediments of the tinto river estuary southwestern spain high absolute concentrations of metals associated to sulfide deposits located at the river source fe cu zn pb cd and as have been determined from the study of major and trace element concentrations in sediment samples obtained in two vibracores in the tinto river estuary in most cases the enrichment factor ef for these metals is over 2 cu zn and as have much higher ef over 10 in surficial samples fe oxy hydroxide precipitation in high chlorinity zones and its scavenging effect on metals is the main control process on the chemical composition of sediment vertical evolution of the sedimentary and geochemical characteristics of the cores show that the estuary has undergone a process of progressive shallowness and a relative increase in acidic river water volume with respect to seawater this effect has originated a downstream displacement of acid mixing processes affecting the estuary which is reflected in higher metal concentrations in sediments of the outer zones of the system

exploring the structure of the mid pleistocene revolution with advanced methods of time series analysis the mid pleistocene climate transition is a complex global change leading to late pleistocene ice ages with increased mean ice volume and dominant 100 ka cycle a thorough understanding of this transition demands quantitative investigations in the time and frequency domains and in the stochastic domain three methods of time series analysis are presented which have been adapted for this purpose they are tested by means of predefined artificial time series and applied to benthic oxygen isotope d18o records which serve as ice volume indicator results are as follows a the time dependent mean shows an increase of 0 35 vs pdb from 942 to 892 ka b evolutionary spectral analysis reveals an abrupt in crease of 100 ka cycle amplitude at approximately 650 ka c probability density function exhibits a bifur cation behavior at approximately 725 ka these find ings point to a multiple transition from a more linear climate system to a strong nonlinear system the signif icant lead of the transition in mean in relation to the 100 ka amplitude change and bifurcation is left open for explanation

five thousand years of atmospheric ni zn as and cd deposition recorded in bogs from nw iberia prehistoric and historic anthropogenic contributions abstract the analysis of environmental archives from across the world has demonstrated that human perturbation of the geochemical cycles of trace metals and the resultant atmospheric metal contamination date back at least several millennia however an understanding of the local processes and timing of changes in trace metal deposition is also essential for a proper global interpretation the iberian peninsula was a major mining area since prehistoric times and the analysis of environmental archives provides a good opportunity to improve our understanding of the history of mining and metallurgy in europe we present the results from three 14 c dated peat cores from the xistral mountains nw iberia these records are used to reconstruct past atmospheric deposition of ni zn as and cd the chronology of the changes in concentrations and metal accumulation rates was found to be concordant in the three bogs and showed great similarity to total pb hg and pb isotope ratios as determined in previous investigations they present a consistent view of changes in atmospheric pollution and the importance of metals in the development of human societies especially i the first evidence of atmospheric metal pollution 3400 years ago which is simultaneous with the expansion of the atlantic bronze koine ii a pollution event between 2350 and 2150 years ago associated to the development of so called celtic culture local late iron age iii a dramatic increase of metal fluxes in roman times iv a severe and rapid increase in the last 250 years corresponding to the beginning of the industrial revolution in europe reflecting the emergence of the new dominant sources of pollution and v the increase of long range atmospheric transport of pollutants our data suggest that all detected ancient until ca 1450 cal bp periods of enhanced ni zn as and cd accumulation may have had an anthropogenic origin related to the onset and development of mining and metallurgy

biomass effects on stalagmite growth and isotope ratios a 20th century analogue from wiltshire england increases in calcite deposition rates combined with decreases in 13c and 18o in three modern stalagmites from brown s folly mine wiltshire england are correlative with a well documented re vegetation above the mine increased soil pco2 resulted in greater amounts of dissolved caco3 in the drip waters which consequently increased annual calcite deposition rates the absence of deposition prior to 1916 28 years after the mine was closed indicates that vegetation had not yet sufficiently developed to allow higher pco2 values to form in the soil lower 13c values through time may reflect the increased input of isotopically light biogenic carbon to the total dissolved inorganic carbon dic 18o decreased synchronously with 13c reflecting the increased importance of isotopically light winter recharge due to greater biomass induced summer evapotranspiration this is the first empirical demonstration that vegetation density can control stalagmite growth rates 13c and 18o contributing critical insights into the interpretation of these climate proxies in ancient stalagmites

the temperature of europe during the holocene reconstructed from pollen data we present the first area average time series reconstructions of warmest month coldest month and mean annual surface air temperatures across europe during the last 12 000 years these series are based on quantitative pollen climate reconstructions from over 500 pollen sites assimilated using an innovative four dimensional gridding procedure this approach combines three dimensional spatial gridding with a fourth dimension represented by time allowing data from irregular time series to be focussed onto a regular time step we provide six regional reconstructed temperature time series as well as summary time series for the whole of europe the results suggest major spatial and seasonal differences in holocene temperature trends within a remarkably balanced regional and annual energy budget the traditional mid holocene thermal maximum is observed only over northern europe and principally during the summer this warming was balanced by a mid holocene cooling over southern europe whilst central europe occupied an intermediary position changes in annual mean temperatures for europe as a whole suggest an almost linear increase in thermal budget up to 7800 bp followed by stable conditions for the remainder of the holocene this early holocene warming and later equilibrium has been mainly modulated by increasing winter temperatures in the west which have continued to rise at a progressively decreasing rate up to the present day

hyperspectral remote sensing monitoring of pyrite mine wastes a record of climate variability pyrite belt spain monitoring of mine waste on sulphide deposits through hyperspectral remote sensing data contributes to predicting surface water quality quantitatively estimating acid drainage and metal contamination on a yearly basis the mineralogy of surface crusts loaded with highly soluble salts is a record of available humidity and temperature along the year a temporal monitoring of salt efflorescence on mine wastes at a mine site in the iberian pyrite belt spain has been mapped in this work using hyperspectral airborne hymap data climate change estimations are made based on oxidation stages derived from well known sequences of minerals tracing sulphides oxidation intensity using archive spectral libraries therefore mine waste weathering products of sulphide mapped from airborne hyperspectral remote sensing data can be used as a short term record of climate change providing a useful tool for assessing environmental geoindicators in semi arid areas

the climate of europe during the holocene a gridded pollen based reconstruction and its multi proxy evaluation we present a new gridded climate reconstruction for europe for the last 12 000 years based on pollen data the reconstruction is an update of davis et al 2003 using the same methodology but with a greatly expanded fossil and surface sample dataset and more rigorous quality control the modern pollen dataset has been increased by more than 80 and the fossil pollen dataset by more than 50 representing almost 60 000 individual pollen samples the climate parameters reconstructed include summer winter and annual temperatures and precipitation as well as a measure of moisture balance and growing degree days above 5 degrees c confidence limits were established for the reconstruction based on transfer function and interpolation uncertainties the reconstruction takes account of post glacial isostatic readjustment which resulted in a potential warming bias of up to 1 2 degrees c for parts of fennoscandia in the early holocene as well as changes in palaeogeography resulting from decaying ice sheets and rising post glacial sea levels this new dataset has been evaluated against previously published independent quantitative climate reconstructions from a variety of archives on a site by site basis across europe the results of this comparison are generally very good only chironomid based reconstructions showed substantial differences with our values our reconstruction is available for download as gridded maps throughout the holocene on a 1000 year time step the gridded format makes our reconstructions suitable for comparison with climate model output and for other applications such as vegetation and land use modelling our new climate reconstruction suggests that warming in europe during the mid holocene was greater in winter than in summer an apparent paradox that is not consistent with current climate model simulations and traditional interpretations of milankovitch theory c 2015 elsevier ltd all rights reserved

sediment and pollen evidence for an early to mid holocene humid period in the eastern sahara a major problem in the study of holocene palaeoenvironments of the arid and wind deflated sahara is the low preservation potential of sediments from which a record of past climatic change can be established several indirect and imprecisely dated pieces of evidence have suggested humid episodes in the holocene that may have supported more productive ecosystems and denser human populations than today searches for reliable proxy data on past climates however have failed to yield satisfactory results we report here the discovery of buried lake muds in north west sudan in the hyperarid core of the eastern sahara which yield sedimentological and palynological data clearly interpretable as recording an early to mid holocene humid episode that supported a relatively deep stratified lake surrounded by tropical savanna woodland vegetation

report of 1st discussion group the last interglacial in high latitudes of the northern hemisphere terrestrial and marine evidence abstract the paleoclimatic informations preserved at some selected sites from high northern latitudes correlative with the last interglacial maximum of isotopic substage 5e have been compiled on a hemisphere scale the mapped compilation reveals much warmer climate conditions on average than present in both terrestrial and marine environments and indicates a northward shift of subpolar and boreal bioclimatic zones the data also suggest that temperature and precipitation gradients were significantly different than those of the holocene with particularly efficient latitudinal and eastward transport of warm air masses the paleoenvironmental and paleoclimate trends through the last interglacial sensu lato isotopic stage 5 are more difficult to assess because the chronostratigraphical framework is poorly constrained nevertheless the data suggest important regionalism in the climatostratigraphical trends in particular the large amplitude climatic cyclicity that characterizes the last interglacial of europe is barely observed elsewhere moreover by the end of the last interglacial isotopic substage 5a conditions slightly cooler than present are recorded in western europe while relatively warm conditions similar to today apparently prevailed in circumpolar regions adjacent to the north atlantic despite the onset of ice growth the last interglacial provides paleosynoptic situations unlike those of the present that may contribute to understanding interactions within the environmental system on a hemispheric scale there is however an imperative need for uniformization of data sets and for more accurate chronological control on regional scales

geochemical variations in estuarine sediments provenance and environmental changes southern spain abstract the geochemical characteristics of the sedimentary infilling in the central basin of the odiel river estuary have allowed the determination of the sediment provenance and the environmental conditions during the last 10 000 years thus sediment provenance can be divided into three stages 1 9060 6500 years bp the estuarine valley materials became the main sediment source because of intense erosion and sedimentation under transgressive conditions 2 6500 3200 years bp the stabilization of the sea level and the current dynamic conditions involved an erosion of the neogene and quaternary formations that acted as sediment sources at approximately 5705 cal year bp a high energy marine event took place suggesting that a tsunami could have affected this area 3 3200 years bp to present the high sedimentation rate of the previous stage and the partial closure of the estuary allowing the acid fluvial discharges from the tinto and odiel to reach the estuary and become the present main source of sediments

climatic and environmental controls on speleothem oxygen isotope values variations in speleothem oxygen isotope values d 18 o result from a complicated interplay of environmental controls and processes in the ocean atmosphere soil zone epikarst and cave system as such the controls on speleothem d 18 o values are extremely complex an understanding of the processes that control equilibrium and kinetic fractionation of oxygen isotopes in water and carbonate species is essential for the proper interpretation of speleothem d 18 o as paleoclimate and paleoenvironmental proxies and is best complemented by study of site specific cave processes such as infiltration flow routing drip seasonality and saturation state and cave microclimate among others this review is a process based summary of the multiple controls on d 18 o in the atmosphere soil epikarst and speleothem calcite illustrated with case studies primary controls of d 18 o in the atmosphere include temperature and relative humidity through their role in the multiple isotope effects variability and modifications of water d 18 o values in the soil and epikarst zones are dominated by evaporation mixing and infiltration of source waters the isotopically effective recharge into a cave system consists of those waters that participate in precipitation of caco3 resulting in calcite deposition rates which may be biased to time periods with optimal dripwater saturation state recent modeling experimental and observational data yield insight into the significance of kinetic fractionation between dissolved carbonate phases and solid caco3 and have implications for the hendy test to assist interpretation of speleothem d 18 o time series quantitative and semi quantitative d 18 o climate calibrations are discussed with an emphasis on some of the difficulties inherent in using modern spatial and temporal isotope gradients to interpret speleothems as paleoclimate proxy records finally several case studies of globally significant speleothem paleoclimate records are discussed that show the utility of d 18 o to reconstruct past climate

iron isotopes in acid mine waters and iron rich solids from the tinto odiel basin iberian pyrite belt southwest spain the isotopic composition of fe was determined in water fe oxides and sulfides from the tinto and odiel basins south west spain as a consequence of sulfide oxidation in mine tailings both rivers are acidic 1 45 ph 3 85 and display high concentrations of dissolved fe up to 420 mmol l 1 and sulphates up to 1190 mmol l 1 the 56fe of pyrite rich samples from the rio tinto and from the tharsis mine ranged from 0 56 0 08 to 0 25 0 1 56fe values for fe oxides precipitates that currently form in the riverbed varied from 1 98 0 10 to 1 57 0 08 comparatively narrower ranges of values 0 18 0 08 and 0 21 0 14 were observed in their fossil analogues from the pliocene pleistocene and in samples from the gossan the oxidized layer that formed through exposure to oxygen of the massive sulfide deposits 0 36 0 12 to 0 82 0 07 in water 56fe values ranged from 1 76 0 10 to 0 43 0 05 at the source of the tinto river fractionation between aqueous fe iii and pyrite from the tailings was less than would be expected from a simple pyrite oxidation process similarly the isotopic composition of gossan oxides and that of pyrite was different from what would be expected from pyrite oxidation in rivers the precipitation of fe oxides mainly jarosite and schwertmannite and lesser amounts of goethite from water containing mainly more than 99 fe iii with concentrations up to 372 mmol l 1 causes variable fractionation between the solid and the aqueous phase 0 98 56fesolid water 2 25 the significant magnitude of the positive fractionation factor observed in several fe iii dominated water may be related to the precipitation of fe iii sulphates containing phases

refining the estimation of metal loads dissolved in acid mine drainage by continuous monitoring of specific conductivity and water level the accurate estimation of metal loads transported by streams is necessary to calculate reliable mass transfers of metals between compartments both at local and global scales this estimation is particularly relevant in the case of the tinto and odiel rivers sw spain due to their significant contribution to the total metal transfer from continents to the ocean at a local scale the metal load transported by streams plays a key role in predicting the biogeochemical evolution of water reservoirs affected by acid mine drainage amd this work uses the relationships between specific conductivity sc and dissolved elements to calculate the metal load of the river meca a tributary of the odiel the sc and the water level were continuously monitored from april 2009 to june 2010 water samples were also collected and measurements of the discharge were carried out manually once a month the relationships between the sc and the concentration of dissolved elements are in general very good r 2

radiometric isotopic and petrographic evidence of changing interglacials over the past 550 000 years from six stalagmites from the serra do courel in the cordillera cantabrica of northwestern spain abstract seventy u th ages from six stalagmites from the cordillera cantabrica in northwestern spain indicate deposition during interglacial but not glacial stages over the last 550 kyr stable isotope data and petrographic observations suggest that within each interglacial conditions typically progressed from drier to wetter consideration of the most precise u th ages suggests that stalagmite deposition occurred in times more predictable from european pollen records than from the global marine isotope record for example during the last interglacial ages suggest deposition in an interval better characterized as the eemian as opposed to mis 5e and during the st germain i or mis 5c interval the same holds for mis 7 where ages suggest deposition during mis 7a and mis 7c but not mis 7e these age ranges for interglacials consistently later than those suggested by the benthic marine record are compatible with warm conditions maintained by thermohaline circulation that simultaneously supplied the moisture for growing ice sheets of the subsequent glaciation trends both within and across these six stalagmites suggest that cooler temperatures were associated with wetter conditions both during interglacials and in conditions intermediate between interglacials and glacials in northern spain in contrast other researchers results from a stalagmite from the last glacial maximum and subsequent deglaciation suggest colder temperatures were associated with drier conditions the two trends combine to suggest wettest conditions in times intermediate between interglacials and glacials compatible with a model in which modern climatic belts from dry arctic to wet european to dry marginal saharan have moved over northern spain in the cycle from glacial to interglacial times extrapolation to a warmer future would suggest drier conditions in the northern iberian peninsula than those of today

geochemistry of acidic rio tinto headwaters and role of bacteria in solid phase metal partitioning abstract mining operations in the rio tinto area southwest spain have created a historical pollution problem in the river and estuary the fate of metals along the rio tinto river and estuary has been previously characterized but little is known about transport and behaviour of metals and other elements in the headwaters of the river the headwaters are situated approximately 100 km north east from huelva at the mediterranean sea with three investigated sites in this area distributed over 100 m inductively coupled plasma atomic emission spectroscopy icp aes of aqueous and solid samples revealed ca fe mg na s si and al concentrations above 0 5 mm in the stream surface waters at all sites trace elements included k cu li mn and zn concentrations of particulate elements generally accounted for less than 10 of the total load in deeper pools along the stream brine water was found with notably higher levels of fe mg s si and al compared to the stream water the brine had a ph of 1 9 while the surface stream waters had ph values of about 2 7 groundwater from the seep on the bank of the stream was found to be chemically distinct from both surface stream water and the brine fe s and al were in the solid samples at 100 mmol kg or more k na p si as ba cu li and mn were characterized by intermediate concentrations 1 0 100 mmol kg a progressive downstream increase in particulate elemental concentrations was observed for p ba mn pb sr v and zn scanning electron microscopy sem showed a variety of bacterial like forms among the suspended particulates in some instances the bacteria appeared to be closely associated with or mineralized by inorganic precipitates transmission electron microscopy tem revealed extensively mineralized bacterial cells in the solid sediment samples the chemical composition of the investigated stream is attributed to inputs from groundwater and brines that likely evolve in response to evaporation during prolonged periods of moisture deficit in the summer planktonic bacteria were prominent components of the suspended particulate fraction in the stream however ph sorption edges for dissolved metals on bacteria are generally above ph 4 0 and therefore it is unlikely that bacterial cells are an important component for transport of dissolved metals in the stream bottom sediments contain abundant highly mineralized bacteria with coatings of poorly crystalline iron oxyhydroxides and hydroxysulfate precipitates such bacterial mineral composites likely contribute to increased solid phase partitioning of dissolved metals in the tinto river system

direct land sea correlations in the last interglacial complex isotopic and pollen analyses of an eastern atlantic core permit the first direct correlation of substages 5e and 5c of the marine climatostratigraphical system with the eemian and st germain i respectively of the classical grande pile pollen sequence north east france the vegetational sequences during the warm intervals of the last interglacial complex 125 000 75 000 yr bp indicate that climatic deterioration occurred late on the mid european continent after the initiation of glaciation over continental masses in high latitudes

geochemistry of quaternary sediments in terraces of the tinto river sw spain paleoenvironmental implications abstract the tinto river shows very high concentrations of toxic elements and acidity from its source in the mining area to its mouth in this paper we studied the evolution of the levels of toxic elements during part of the quaternary from the analysis of fluvial deposits that forming terraces were originated by the dynamics of the tinto river using a detailed geomorphological cartography up to nine terrace levels were differentiated in the lower sector of the basin whose ages range from the pleistocene to the holocene sampling and geochemical analyses major elements and trace were carried out in six of these levels in addition to sediments of the current flood plain the results of these analyses do not show any bias from the mid pleistocene t8 terrace 8 to the early holocene t1 moreover these geochemical contents are similar to the average values obtained by other authors for the entire south portuguese zone of the iberian massif however the current sediments of the tinto river t0 show a sharp increase in the levels of as cu pb and zn compared to the rest which indicates a serious increment of contamination by toxic elements although there are evidences on the existence of a natural process of oxidation of sulfides since the miocene the amounts of toxic elements released should be very small compared to those generated since the beginning of the mining activities in the iberian pyrite belt