holocene paleoenvironmental changes inferred from diatom assemblages in sediments of kusawa lake yukon territory canada abstract the southwest yukon territory canada is an important region for recovering sensitive records of holocene paleoclimatic change more information is needed however to constrain the timing of the major holocene climatic transitions and to understand associated impacts on different ecosystems for example paleolimnological studies have focused on small lakes and ponds but the history of large lakes has received little study we analyzed diatom assemblages species richness valve concentrations and biogenic silica in the sediments of kusawa lake 60 16 5 n 136 10 9 w 671 m a s l to reconstruct the responses of this large surface area 142 km 2 deep z max 135 m freshwater ecosystem to holocene climatic transitions diatoms colonized the lake soon after ice retreat around 11 000 cal yr bp assemblages throughout the record were dominated by planktonic types diatom concentrations and biogenic silica were high during the holocene thermal maximum between 10 700 and 7300 cal yr bp then began to decrease in response to cooling associated with orbitally driven reductions in insolation diatom assemblages shifted towards taxa with lower surface water temperature optima after 8300 cal yr bp perhaps in response to abrupt and progressive cooling our study confirms that diatom assemblages in large lakes are sensitive to regional scale paleoclimatic changes

fossil charcoal in cretaceous tertiary boundary strata evidence for catastrophic firestorm and megawave abstract organic matter separated from calcareous sandstone from the upper portion of a deep water tsunami deposit at arroyo el mimbral taumalipas mexico which marks the biostratigraphically defined cretaceous tertiary boundary consists primarily of fossil charcoal including semifusinite and pyrofusinite analytical pyrolysis gas chromatography mass spectrometry revealed the highly aromatic and polyaromatic character of the organic matter assemblage typical of the products of partial combustion the organic matter probably originated as terrestrial vegetation that was caught in a firestorm and subsequently transported far offshore in the backwash of a megawave these data are consistent with the hypothesis of combustion of large masses of vegetation triggered by a giant extraterrestrial impact in the gulf caribbean region probably forming the chicxulub crater in yucatan at the very end of the cretaceous period

chemistry of rainwater in the massif central france a strontium isotope and major element study atmospheric aerosols sea salt crustal dust and biogenic aerosols are the primary source of dissolved species in rainwater as well as one of the sources of dissolved species in river water chemical weathering studies require quantification of this atmospheric input the crustal component of atmospheric input can have various origins both distant and local the proportions of the various inputs marine distant or local are determined in this study strontium isotope ratios and ca na k mg al cl so4 no3 and sr concentrations were measured in rainwater samples collected in the massif central france over a period of one year each sample collected automatically represents a monthly series of rain events chemical composition of the rainwater samples varied considerably and the 87sr 86sr ratios ranged between 0 709198 and 0 713143 using na as an indicator of marine origin and al for the crustal input in rain samples the proportion of marine and crustal elements was estimated from elemental ratios a marine origin of 4 to 100 of cl of 0 6 to 20 of the so4 of 1 to 10 of ca 1 to 40 of k 4 to 100 of mg and 1 to 44 of sr was determined strontium isotopes were used to characterize the crustal sources the 87sr 86sr ratios of the crustal sources varied considerably from 0 7092 to 0 71625 and indicate the occurrence of multiple sources for the crustal component in the analysed rainwaters

identification of some bicyclic alkanes in petroleum abstract bicyclic alkanes containing the drimane skeleton have been identified in crude oils and sediments by synthesis of model compounds two other bicyclic alkanes whose skeletons do not conform to the isoprene rule have also been identified from mass spectral data a correlation between the relative concentration of c 29 steranes and diasteranes and drimane and two c 15 bicyclanes in an extensive sample suite suggests a similar mechanism is involved in the formation of diasteranes and the two c 15 bicyclanes in the subsurface the widespread occurrence of drimanes and drimane related compounds in crude oils and sediments indicates that these compounds are derived from a ubiquitous source the presence of methyldrimanes in a sample rich in methylhopanes suggests that drimanes and hopanes may be derived from similar precursors

quaternary pollen taphonomy examples of differential redeposition and differential preservation pollen assemblages are affected by a variety of processes between dehiscence and recovery here two examples from western canada illustrate two of the most important biases affecting pollen assemblages after production and initial dispersal a site in canada s yukon territory provides evidence of selective redeposition of penecontemporaneous pollen grains which is detectable only through paired coring a deposit on the floor of a kettle depression shows trends in the ratios of extra local pollen types which are opposed to the trends shown in a core taken from the slope of the same depression this is explained as a trend to reduced mobility of saccate grains with time due to increased permeability of the substrate on the kettle slope a study of the differential degradation of populus pollen illustrates the complexities of pollen preservation populus pollen is generally recognized as more susceptible to corrosion than are most other pollen types the poor preservation of this pollen type is attributed largely to its lack of harmomegathic adaptation and low sporopollenin content this real susceptibility is compounded by the pollen grain s lack of distinctive surface ornamentation inhibiting recognition of damaged grains at least part of the general impression of poor preservation of populus pollen may be due to a recent increase in the abundance of populus on the landscape in western canada early studies in this region may have sampled sediments from before the increase in populus and compared their pollen spectra with post populus increase vegetation

the geology and palynology of lower and middle pennsylvanian strata in the western kentucky coal field abstract the western kentucky coal field is the southern tip of the eastern interior or illinois basin pennsylvanian rocks in this area which include conglomerate sandstone siltstone shale limestone and coal were deposited primarily in coastal deltaic settings at a time when western kentucky was located close to the equator this paper discusses temporal changes in regional sedimentation patterns and coal forming floras of lower and middle pennsylvanian strata in the western kentucky coal field lower pennsylvanian strata of the caseyville formation are characterized by paleovalley filling sedimentation patterns and extabasinal quartz pebbles caseyville formation coals are characteristically thin and discontinuous and were strongly influenced by subsidence within underlying paleovalleys and the dissected lower pennsylvanian paleotopography caseyville coals are commonly dominated by lycospora but can also have variable palynofloras which probably reflects variable edaphic conditions and edge effects within small patchy paleomires tradewater formation strata show increased marine influences and tidal estuarine sedimentation especially in the middle and upper parts coal beds in the lower part of the tradewater typically are thin and discontinuous although some economically important beds are present coals become thicker more abundant and more laterally persistent towards the top of the formation palynologically lower and middle tradewater formation coals are dominated by lycospora but begin to show increased amounts of tree fern spores middle and upper tradewater coals are thicker and more continuous and contain high percentages of tree fern spores in addition cordaite pollen is locally abundant in this interval carbondale and shelburn desmoinesian strata are much more laterally continuous and occur within classic cyclothems that can be traced across the coal field cyclothems have long been interpreted as being eustatically driven and glacio eustacy controlled not only sedimentation but also the formation of desmoinesian paleomires palynologically carbondale and shelburn coals are either dominated by lycospora or have heterogeneous palynofloras palynologic and coal quality data suggest that hydrologic base level may have been the primary control on desmoinesian paleomires rather than paleoclimate as the coals display rheotrophic rather than ombrotrophic characteristics

pollen analysis of postglacial sediments from eildun lake district of mackenzie n w t canada sediment from eildun lake located at 63 8 6 n 122 46 5 w in the northern boreal forest was cored to a depth of 268 cm and analyzed for pollen content pollen percentages and 14c dates suggest a

patterns of water 87sr 86sr variations in oil gas and water saturated rocks implications for fluid communication processes distances and timescales abstract this study reviews 87sr 86sr depth profiles of formation waters sampled by sr residual salt analysis sr rsa from 100 oil gas wells and research sites including reservoirs with clastic and carbonate host rocks and with gas oil and water as the continuous fluid phase globally the water data form a smooth trend between low seawater like 87sr 86sr ratios 0 706 at shallow depths and high 0 724 ratios in deeply buried rocks where water rock interaction dominates we test the hypothesis that 87sr 86sr depth profiles in individual wells could be influenced by diffusional mixing processes by developing 1d diffusion mixing equations to simulate compositional patterns through time and comparing them with observed profiles different combinations of boundary and initial conditions generate various patterns characteristic of diffusion including non steady state curves relating to incomplete mixing and steady state patterns such as vertical or inclined straight lines where initial heterogeneities have fully mixed the dataset yielded 193 occurrences of these patterns steady state patterns are more common and longer in water zones while non steady state patterns are more common and longer in oil and gas zones the detection of diffusional mixing patterns in hydrocarbon saturated rocks suggests that diffusion is active although on average a factor of 13 18 slower than in comparable water saturated rocks pattern generation and equilibration times were modelled for each non steady state pattern and compared with the time since reservoir filling with oil gas revealing that 90 of them could have been generated since filling but 60 of them would already have mixed to steady state had the initial compositional heterogeneities arisen during or before reservoir filling this is critical evidence that at least some of the initial heterogeneities must have arisen and subsequently partially mixed after filling these patterns tend to be short the evidence for post fill water rock interaction and diffusive transport has important implications for porosity permeability prediction indicating that key diagenetic processes like quartz cementation may be inhibited by hydrocarbon filling but not stopped altogether compositional differences of water within oil gas zones reveal the folly of using one aquifer water sample as the basis for interpreting water saturations from well resistivity logs for in place resource estimation sr rsa studies may thus be useful in designing water sampling strategies

palynologie et morphogenese recente dans le bassin du grizzly creek territoire du yukon pollen analysis of three sections from the grizzly creek basin yukon territory was undertaken in order to reconstruct the paleoecology of the region over the last two millennia diagrams for two sites show three well defined pollen zones whose boundaries are based on fluctuation of pollen spectra the oldest zone corresponds to vegetation comparable to that of the present and a climate similar to or a little colder than the present climate in zone 2 the strong decline of picea is interpreted as a break in pollen production caused by a decrease in precipitation and a warming of the climate the forest survived for several centuries in a state of degeneration which favoured the development of a stratum of shrubs and herbaceous plants zone 3 reflects a return to vegetation and to climatic conditions similar to those of zone 1 the positions of two layers of volcanic ash dated at approximately 1230 and 1890 years bp and corresponding to two lobes of white river ash indicate the rhythm of sedimentation

organic geochemical study of sequences overlying coal seams example from the mansfield formation lower pennsylvanian indiana abstract roof successions above two coal seams from the mansfield formation lower pennsylvanian in the indiana portion of the illinois basin have been studied with regard to sedimentary structures organic petrology and organic geochemistry the succession above the blue creek member of the mansfield formation is typical of the lithologies covering low sulphur coals 2 the transgressive regressive packages above both seams reflect the periodic inundation of coastal mires by tidal flats and creeks as inferred from bioturbation and sedimentary structures such as tidal rhythmites and clay draped ripple bedforms geochemistry and petrology of organic facies above the blue creek coal suggest that tidal flats formed inland in fresh water environments these overlying fresh water sediments prevented saline waters from invading the peat contributing to low sulphur content in the coal above the unnamed coal trace fossils and geochemical and petrological characteristics of organic facies suggest more unrestricted seaward depositional environment the absence of saline or typically marine biomarkers above this coal is interpreted as evidence of very short periods of marine transgression as there was not enough time for establishment of the precursor organisms for marine biomarkers however sufficient time passed to raise so42 concentration in pore waters resulting in the formation of authigenic pyrite and sulphur incorparation into organic matter

variations in the sterane carbon number distributions of marine source rock derived crude oils through geological time abstract the analysis of the sterane data of a large set of crude oils 414 derivedfrom marine carbonate 27 and siliciclastic source rocks 14 where influences of terrestrial or lacustrine derived organic matter can reasonably be excluded shows that there are increases in the relative content of c28 steranes and decreases in the relative content of c29 steranes through geological time there are no consistent variations in the relative content of c27 steranes through time with one major exception a proterozoic oil from oman palaeozolic and older crude oils are thus generally characterised by strong predominances of c29 steranes and low relative concentrations of c28 steranes significantly higher proportions of c28 steranes and lower proportions of c29 steranes occur in oils derived from jurassic and upper cretaceous source rocks these changes through time do not appear to reflect the chemical evolution of the sterols of one particular variety of marine organism the increase in c28 steranes may be related to the increased diversification of phytoplantonic assemblages in the jurassic and cretaceous possible sources of the c28 sterols necessary for the observed changes in crude oil steranes includes diatoms coccolithophores and dinoflagellates although the technique does not give an accurate means of determining the age of the source rock of a crude oil it is possible to distinguish younger crudes derived from the upper cretaceous and tertiary from palaeozoic and older crudes

geochemical and petrographical characteristics of low rank balingian coal from sarawak malaysia its implications on depositional conditions and thermal maturity abstract geochemical and coal petrographical analyses were undertaken on low rank upper pliocene balingian coal from sarawak malaysia in an attempt to reconstruct the conditions during peat accumulation and the subsequent coalification processes chemically the coal in this study is characterised by high moisture low ash yield and low sulphur content the low ash yield and low sulphur content together with the lack of epiclastic partings clearly indicate that it was deposited in ombrotrophic raised bogs the coal was plotted in the type iii terrigenous kerogen zone of the van krevelen diagram with h c value below 0 9 this shows that the coal was derived from plant materials of terrigenous origin and is still immature for petroleum generation the petrographical study reveals nonetheless the expulsion of early generated hydrocarbons from the disintegration of suberinite and also from phlobaphinite and cutinite petrographically the coal is dominated by huminite with low to moderate amounts of liptinite and low amounts of inertinite pointing to predominantly anaerobic deposition conditions in the paleomires with limited thermal and oxidative tissue destruction most of the studied samples are characterised by low tpi and high gi values and are plotted on the marsh field of the diessel s diagram or it could also originate from decomposed wood in forested swamps nevertheless coals originating from both these sources usually generate high ash yield which is not the case for the studied coal this shows that the interpretation as suggested by the diessel s diagram is not valid for the studied coal the coal has a mean random huminite reflectance between 0 26 and 0 35 suggesting a lignite coal rank for the coal nevertheless geochemical classification based on total moisture and calorific value suggests a subbituminous c rank

holocene vegetation and climatic change in the peace river district canada a sediment core from a pond on the alberta plateau in the peace river district of british columbia was studied using pollen analysis and radiocarbon dating percentage and influx diagrams were produced and radiocarbon dates were corrected to calendar years to calculate the sedimentation rate the 231 cm core terminated in clay and a basal date of 7250 120 years bp was obtained several thousand years after the recession of glacial lake peace the formation of the pond is interpreted as resulting from a climatic change probably a transition from the peak of the hypsithermal zone 1 from 7250 to 5500 years bp is interpreted as representing a seasonal slough with upland vegetation percentages consistent with a boreal forest at about 5500 years bp a permanent pond with surrounding sedge wetlands was formed vegetation has been essentially modern during the last 3100 years measurements of spruce grains suggest the presence of black and white spruce throughout the pollen record the formation of perma

significance of organic matter in recording paleoenvironmental conditions of the safa formation coal sequence maghara area north sinai egypt abstract five coal and shale core samples of the middle jurassic safa formation were taken from a newly drilled water well at the depth interval from 191 to 208 m and have been investigated in this study detailed organic and inorganic geochemical analyses of the safa formation reveal no significant differences between the upper seams and the main seam the extracts of the coal samples have an unusual n alkane distribution the gc traces are dominated by unusual compounds eluting between n c19 and n c21 these compounds are thought to be diterpanes which suggest significant conifer contributions to the coals higher amounts of hopanes and higher carbon preference index cpi values n c22 to n c30 show significant bacterial contributions in samples characterized by high values of tissue preservation index tpi the c31 22s 22s 22r hopane and c29 20s 20s 20r sterane ratios show least variation through the shale coal sequence shale and coal samples from the upper and main seams are characterized by high relative abundance of 17 h hopanes which could be derived from non microbial organisms such as ferns the petrographic and geochemical evidences suggest that the maghara coal was formed in a wet forest swamp environment situated in a marine influenced lower delta plain

relationship between petroleum composition and depositional environment of petroleum source rocks crude oils of nonmarine source can be distinguished from those of marine shale source and from oils originating in marine carbonate sequences by using a battery of geochemical parameters as demonstrated with a sample suite of nearly 40 oils a novel parameter based on the presence of c30 steranes in the oil was found to be a definitive indication of a contribution to the source from marine derived organic matter a second novel parameter based on monoaromatized steroid distributions was effective in helping to distinguish nonmarine from marine crudes and can be used to gauge relative amounts of higher plant input to oils within a given basin sterane distributions were similarly useful for detecting higher plant input but were less effective than monoaromatize steroid distributions for making marine versus nonmarine distinctions concentrations of high molecular weight paraffin can also be effective nonmarine indicators but are influenced by maturation and biodegradation processes certain algal derived nonmarine oils may show little high molecular weight paraffin response oils from carbonate sources with a few exceptions can be distinguished by having low pristane phytane ratios low carbon preference indexes and high sulfur contents gammacerane indexes and carbon isotope ratios of the whole crude are not effective in distinguishing these types of environmental differences on a global basis

chemical characteristics of liptinite macerals in humic and sapropelic coals abstract according to previous studies alginite does not occur in humic coals however in coals from the saar district f r germany alginite was identified by fluorescencemicroscopy in addition high amounts of an undeterminable liptinite maceral were found and tentatively explained as an alteration product of alginite therefore organic geochemical methods were used to characterize and identify this unknown liptinite maceral organic geochemical parameters such as cpi pristane phytane ratio and methylphenanthrene index show not only a dependence from coal rank but also yield additional information about the type of organic matter input and the depositional environment of the coals a series of coals of different origins around 0 8 vitrinite reflectance were investigated to determine how far the geochemical parameters reflect change in facies the samples included cannel boghead and resinite rich coals as well as isolated durain bands with increasing amounts of alginite in the coal the cpi pristane phytane and c 4 naphthalene phenanthrene ratios of the extracts decrease as illustrated by two representatives samples some resinite and sporinite rich coals show a primarily naphthalene derived aromatic composition whereas some alginite rich coals of the same rank show phenanthrene and its derivatives to be dominant with respect to technological properties most coals from the saar district correspond with a higher rank than indicated by reflectance measurements those coals in general show lower values of the aforementioned ratios in comparison with ruhr coals of similar vitrinite reflectance values

strontium isotope geochemistry of groundwater affected by human activities in nandong underground river system china abstract the nandong underground river system nurs is located in a typical karst area dominated by agriculture in se yunnan province china groundwater plays an important role in the social and economical development in the area the effects of human activities agriculture and sewage effluents on the sr isotope geochemistry were investigated in the nurs seventy two representative groundwater samples which were collected from different aquifers calcite and dolomite under varying land use types both in summer and winter showed significant spatial differences and slight seasonal variations in sr concentrations and 87sr 86sr ratios agricultural fertilizers and sewage effluents significantly modified the natural 87sr 86sr ratios signature of groundwater that was otherwise dominated by water rock interaction three major sources of sr could be distinguished by 87sr 86sr ratios and sr concentrations in karst groundwater two sources of sr are the triassic calcite and dolomite aquifers where waters have low sr concentrations 0 1 0 2 mg l and low 87sr 86sr ratios 0 7075 0 7080 and 0 7080 0 7100 respectively the third source is anthropogenic sr from agricultural fertilizers and sewage effluents with waters affected having radiogenic 87sr 86sr ratios 0 7080 0 8352 for agricultural fertilizers and 0 7080 0 7200 for sewage effluents respectively with higher sr concentrations 0 24 0 51 mg l due to the overlapping 87sr 86sr ratios it is difficult to distinguish the sources of sr in groundwater samples contaminated by agricultural fertilizers or sewage effluents based only on their 87sr 86sr ratios however 87sr 86sr ratios do provide key information for natural and anthropogenic sources in karst groundwater

the link between surface water and groundwater based drinking water strontium isotope spatial distribution patterns and their relationships to danish sediments abstract the hydrological relationship between surface waters and groundwaters in many regions of the world is well known and the effects of their mutual interaction and interaction with the soils and bedrocks with respect to resulting changes in their chemical composition are well studied in this study we add to this knowledge by comparing the distributional patterns of strontium sr isotopes in previously published 192 surface water samples with those of newly acquainted sr isotope data from groundwater based drinking water samples extracted from 163 of the major waterworks in denmark the aim is to investigate potential compositional changes that might derive from the interaction with the aquifer lithology or overlying sediments and soils the average sr isotope signatures of surface and groundwater based drinking waters define 87sr 86sr values of 0 7096 0 0015 2 and 0 7088 0 0013 2 respectively the skewed distribution of sr isotope compositions in groundwaters towards lower 87sr 86sr values indicates enhanced contribution of natural carbonate derived strontium with depth while slightly elevated 87sr 86sr signatures in surface waters may reflect the diminished contribution of sr from carbonates in the glaciogenic sediments due to their progressive acid dissolution strontium concentrations sr in groundwater based drinking water from the participating major waterworks define a country wide average of 1 17 mg l and the distributional pattern shows an east west decreasing trend lowest concentrations are found in the west jutland glaciogenic province wjgp average sr 0 36 mg l and in the northernmost tip of jutland a corresponding pattern although less pronounced is also depicted by the 87sr 86sr signatures of groundwater based drinking water whereby increasing 87sr 86sr values from zealand through funen into the jutland peninsula correspond with increasing thickness of glaciogenic overburden providing though mass balance wise subordinate radiogenic sr to the natural carbonate dominated groundwaters the highest 87sr 86sr values are recorded in waters from northern jutland possibly reflecting the admixture of radiogenic strontium from late glacial and post glacial glacio isostatic adjustment related marine aquifers generally the surprisingly rather homogeneous and similar distributional patterns of 87sr 86sr signatures of danish aquifers and surface waters implies a strong and dominant control of sr by natural clastic reworked carbonate components in the quaternary miocene and holocene sediments and to lesser degree with the exception of northern central jutland and eastern zealand from the pre quaternary limestone dominated basement directly our results are consistent with a tight hydrological and geochemical interrelationship between surface waters and groundwaters in denmark there is a need for further investigations of the effects of advanced treatment of soft acidic groundwater based drinking water on the concentrations and isotopic signatures of trace elements such as sr however our study lends support for the adequate use of sr isotope signatures of either of these waters to characterize the isotope compositional range of bioavailable fractions relevant for authenticity identification forensic studies and for prehistoric and modern human and animal proveniencing

geogenic and anthropogenic lead isotope signatures in the urban environment of natal ne brazil in this study the effect of anthropogenic emissions on the lead isotopic composition of sediments from the potengi jundiai river system near the fast growing city of natal ne brazil is investigated the lead isotope signatures of sediments from the region of natal were measured by icp qms and can be discussed in terms of three different end members of lead two geogenic lead endmembers can be distinguished and also be spatially separated as higher lead isotope ratios occur in the vicinity of the town of macaiba while the lead isotope ratios decrease towards the city of natal and the mouth of the estuary proterozoic rocks of different age are potential lead sources as paleoproterozoic rocks occur in the catchment of jundiai river and younger neoproterozoic rocks predominate towards the mouth of the river the lead isotope signatures of the anthropogenically affected samples deviate from the signatures of the unaffected samples indicating the existence of a third anthropogenic source of lead this source represents the lead isotope signature of anthropogenic emitters like waste and coal combustion which is also revealed by other geochemical studies conducted in brazil

holocene migration of lodgepole pine pinus contorta var latifolia in southern yukon canada a palynological reconstruction n 25 profiles suggests that the northern extent of lodgepole pine pinus contorta var latifolia engelmann ex s watson occurred between 59 and 60 n latitude in

palaoecologic trends and petroleum potential of upper carboniferous coal seams of western germany as revealed by their petrographic and organic geochemical characteristics abstract petrographic compositions of microscopically homogeneous vertical sections in coal profiles from the ruhr basin northwestern germany are reported the studied coal seams of late westphalian age are between 0 4 and 2 4 m thick mean vitrinite reflectivities in the range of 0 1 0 thus indicating high volatile a bituminous coal changes in the organic facies within the coal profiles are common and can be linked to changes of plant communities and preservation conditions in the depositional environments also associated variations in mineral content are usually found although patterns of changes in maceral and mineral contents are complex some general trends have been observed continuous development from seat earth to coal with vitrinitic roots and detritic liptinites and inertinites representing the initial stage of peat and coal evolution just above the base thick vitrinite rich sections with abundant mudstone layers are overlain by inertinite rich sections with low mineral and high sporinite contents the latter may represent highly degraded oxidized peats that accumulated at morphologically elevated areas deposition of clastic roof strata had only a minor influence on organic facies coals and dispersed organic matter in these clastic rocks are in the main similar in maceral group composition organic geochemical characterization of selected lithotypes revealed significant differences between coals and dispersed organic matter this can be explained by trapping of generated hydrocarbons in the coals differences in elemental compositions of coals of the same organic facies at different ranks vitrinite reflectance of 0 70 and 0 92 respectively reflect a loss of about 20 wt co 2 bitumen water during this maturation stage gas chromatographic mass spectrometric analyses of the saturated hydrocarbon fraction in solvent extracts separated from selected samples reveal that all samples contain the same classes of compounds namely straight chain alkanes hopanoids and isoprenoids but that there is a significant difference in the relative abundance of these classes of compounds in the different coals

organic geochemistry of dsdp site 467 offshore california middle miocene to lower pliocene strata abstract results of the analyses of twenty three samples from the middle miocene to lower pliocene strata from dsdp site 467 offshore california are presented the analyses were performed with the aim of determining the origin of the organic matter the stratigraphic section s hydrocarbon generation potential and extent of organic diagenesis organic carbon contents are an order of magnitude greater than those typically found in deep sea sediments suggesting an anoxic depositional environment and elevated levels of primary productivity hydrocarbon generation potentials are above average for most samples the results of elemental analyses indicate that the kerogens are primarily composed of type ii organic matter and are thermally immature analysis of the bitumen fractions confirms that the samples are immature in cores from 541 to 614 meters the gas chromatograms of the c 15 non aromatic hydrocarbon fractions are dominated by a single peak which was identified as 17 h 18 h 21 h 28 30 bisnorhopane this interval is the same area in which the highest degrees of anoxia are observed as reflected by the lowest pristane phytane ratios this correlation may have some implications with regard to the origin of the bisnorhopane and its possible use as an indicator of anoxic depositional conditions within thermally immature sediments

montane climate and vegetation dynamics in easternmost beringia during the late quaternary abstract new and published palynological data are used to investigate the quaternary vegetation history of high elevation sites in the mackenzie mountains of easternmost beringia northwest territories canada during some previous interglacials sites that are presently treeless supported spruce forest indicating conditions were warmer than present and possibly warmer than at any time in the holocene no information is available on vegetation in unglaciated portions of the mountains during the last glacial maximum but in the lateglacial ca 12 000 10 000 14 c yr bp a shrub and herb dominated vegetation characterized in the pollen record by artemisia betula salix gramnoids and herbs grew at all elevations and extended in a continuous corridor southwards to alberta populus balsamifera probably grew up to and above present treeline between about 11 000 and 9000 yr bp the late pleistocene vegetation of the mackenzie mountains contrasts with the rest of eastern and central beringia which supported a betula dominated shrub tundra by 12 000 yr bp betula shrub tundra expanded at all elevations in the mountains by 10 000 yr bp followed by the expansion of picea glauca and picea mariana forest at ca 8000 yr bp there is evidence for limited elevational shifts in treeline during the holocene picea population densities in the forest tundra were probably greater than at present in the early and mid holocene vegetation changes in the mackenzie mountains during this time are consistent with increased summer insolation and temperatures during the early to mid holocene higher resolution analysis decadal to century scale of small lake basins at treeline in this region also provide evidence for a late holocene increase in forest tundra density and or a treeline rise centered on 3000 yr bp slight warming at this time has been noted at sites in the southern rocky mountains and provides evidence for century scale climatic fluctuations superimposed on the longer term changes resulting from variations in insolation

strontium isotopes as tracers of groundwater induced floods the somme case study france major ions trace elements and o h and sr isotopes have been determined for surface water and groundwater in the somme catchment northern france the present study using a coupled hydrological and geochemical stable and sr isotopes approach focuses on the interactions between ground and surface water stable water isotopes 18o 2h show that all waters have a purely local origin from precipitation without significant evaporation or water rock interaction as all points plot close to the general meteoric water line water chemistry in the different catchments shows large variations in major element contents plotting na vs cl contents and mg2 no3 k so42 sr2 concentrations reveals a slight variations in groundwater composition b agricultural input into surface waters and c some similarities between ground and surface waters suggesting the former to be responsible for the chemical signature of the dissolved river load strontium isotope ratios measured in groundwater range from 0 70769 to 0 70808 clearly higher than that of chalk matrix water 0 707337 variations of sr isotope signatures in groundwater from the chalk aquifer are significant and help identifying different groundwater bodies the different signatures in groundwater are better explained by matrix heterogeneity which can present lateral facies variations than by a strong anthropogenic influence the sr isotope compositional range in surface waters is very wide varying from 0 70775 to 0 70816 and defining a trend towards a more radiogenic sr isotope signature with high sr contents and high mg sr ratios the relationship between 87sr 86sr and the mg sr ratios allows different end members to be defined the rivers are influenced by anthropogenic disturbance even during flood periods and river water has geochemical characteristics very similar to those of groundwater indicating a strong influence from groundwater feeding the rivers

hydrogeological assessment of a deep seated coastal landslide based on a multi disciplinary approach abstract this study focuses on the understanding of the hydrogeological functioning of a complex landslide affecting the coastal municipality of villerville normandy france we wish to provide a conceptual model of functioning using a multi disciplinary approach a set of geomorphological geological and hydrological data as well as in situ observations were first used to understand the main landslides processes new acquisitions were then carried out to strengthen our hypotheses thanks to passive geophysics sp and the characterization of physicochemical parameters of surface waters the joint analysis of former ert surveys and sp results is of significant interest for correlating hydrokinetic information measured at the surface with resistivity tomograms which provide internal information this study highlights 1 a division of the behaviour into three parts from east to west 2 variable internal dynamics highlighted by geology and electric fields 3 a preferential discharge of the continental water table upstream of the central area of the landslide this work tends to demonstrate that on the basis of initial in situ knowledge available on many study areas the understanding of the hydrogeological functioning can be substantially improved by implementing light and inexpensive surveys also suitable for large and complex landslides

unraveling petroleum mixtures from the south viking graben north sea a study based on δ13c of individual hydrocarbons and molecular data abstract mixtures of compositionally different petroleum occur in the norwegian north sea one of the world s major oil producing regions the objective of the present contribution was to appraise the source maturity in reservoir mixing and alteration processes in a set of condensate and oil samples covering the main producing areas in the south viking graben svg furthermore this study focused on unraveling complex mixtures of petroleum and quantifying mixing ratios of hydrocarbons generated from jurassic source rocks the present research was based on a multiparameter approach that comprised the molecular composition of light hydrocarbons and heterocyclic and polycyclic aromatic compounds as well as the 13c of individual hydrocarbons in oils condensates and upper and middle jurassic source rock extracts from the svg according to the relative contribution of oils from type iii kerogen rich source rocks seven populations a g of mixed petroleum were identified by combining source related ratios of heterocyclic and non heterocyclic aromatic hydrocarbons and 13c values of n alkanes pristane pr and phytane ph the heterocyclic and polycyclic aromatic hydrocarbons provided a useful means to discriminate mixed hydrocarbons from source rocks of distinct organic matter type depositional environment and lithology in the svg the 13c enrichments of c10 c14 n alkanes and pr and ph were good indicators of the scale of the terrigenous source contribution and allowed quantitative determination of the proportions of jurassic source contributions enriched in type ii and type iii kerogens in complex petroleum mixtures from the southern part of the svg

geological controls on the sulphur content of coal seams in the northumberland coalfield northeast england the sulphur content of coal is an important consideration when developing reserves for exploitation driven by emission limits from power stations becoming more stringent variations in the sulphur content of westphalian a and b coals from the predominantly freshwater northumberland coalfield northeast england were studied according to their regional stratigraphic and in seam location the observed variation in sulphur content spatially increases towards the source area away from more marine influenced areas with increased sulphur content through time linked to changes in the general depositional environment as conditions became more marine influenced a model of basinal surface water and groundwater flow driven by post depositional source area tectonism is thought to have played only a minor role in contributing secondary sulphur to the coal however the isotopic composition of coal pyrite shows a similar range in composition to that of pyrite and other sulphides from the north pennine orefield along the southern margin of the coalfield suggesting an additional potential source of secondary sulphur as sulphur rich fluids were expelled northwards through the coal measures during early permian variscan transpression from the south the westphalian a and b are interpreted as third order depositional sequences defined by third order maximum flooding surfaces each sequence is made up of several coal bearing fourth order parasequences which tend to be more brackish to marine in character on either side of the third order maximum flooding surfaces when base level was relatively high the lowest sulphur coals are confined to the lower to middle relative low stand part of the westphalian a third order base level curve and the lowest part of the westphalian b third order base level curve this difference is attributed to a more rapid rise of base level in the westphalian b the stratigraphic and spatial distribution of coal sulphur has been used as a guide to prediction of reserve identification for surface mining operations

tracking multiple sr sources through variations in 87sr 86sr ratios of surface waters from the aljustrel massive sulphide mining area geological versus anthropogenic inputs abstract this study presents major and trace element data and 87sr 86sr ratios for surface waters from a small watershed draining the aljustrel sulphide mining area south portugal the watershed is located in a geologically complex area comprising two main compartments the northern compartment is dominated by cenozoic formations and does not bear any mining activity whilst the southern compartment is underlain by rocks from both the cenozoic sedimentary cover and the mineralized sequences of the variscan paleozoic basement of the south portuguese zone based on the available geochemical and isotopic data the analysed water samples can be roughly divided into five main groups a group 1 corresponds to amd contaminated water drainages from the southern part of the catchment showing ph 8 marked depletions in so4 and heavy metals and displaying sr isotopic compositions similar to rainwater 87sr 86sr 0 7097 0 7098 c group 3 includes mixed type stream waters with ph and elemental isotopic signatures intermediate between those of groups 1 and 2 d group 4 comprises the samples collected at two lime treated water dams from the mining area that are clearly distinguished from the impacted waters of group 1 by their elevated ca mg and sr concentrations and low 87sr 86sr ratios 87sr 86sr 0 7085 0 7091 e group 5 includes clean waters from two dams located upstream of the ore processing site which are dominantly supplied by direct precipitation and surface runoff and have ph 6 very low so4 and metal concentrations and 87sr 86sr ratios varying between 0 7094 and 0 7108 variations in the 87sr 86sr ratios and sr concentrations of the analysed waters are attributed to mixing of two main end members atmospheric meteoric waters local rainfall runoff with low sr contents and 87sr 86sr ratios 0 7095 and more radiogenic waters derived from the aljustrel mining area the highly radiogenic signatures of the southern tributaries appear to have been controlled by weathering of plagioclase from the acid volcanic rocks of the paleozoic basement enhanced by mining activities pyrite oxidation although released strontium from gangue carbonates could have locally contributed to the fluctuations of sr contents and 87sr 86sr ratios observed in some of these water samples by contrast the low 87sr 86sr ratios and relatively high sr cl and na concentrations shown by the surface waters draining the northern compartment suggest that these tributaries correspond to meteoric waters that have gained cl na and sr through wash out of cenozoic deposits containing finely disseminated halite layers finally the decrease in the 87sr 86sr ratios and elevation of sr contents observed in the samples from the lime treated water dams support the involvement of an anthropogenic source of sr with 87sr 86sr ratios lower than that of rainfall

postglacial climates inferred from a lake at treeline southwest yukon territory canada abstract pollen chironomid and ostracode records from a lake located at alpine treeline provide regional paleoclimate reconstructions from the southwest yukon territory canada the pollen spectra indicate herbaceous tundra existed on the landscape from 13 6 11 ka followed by birch shrub tundra until 10 ka although picea pollen dominated the assemblages after 10 ka low pollen accumulation rates and picea percentages indicate minimal treeline movement through the holocene chironomid accumulation rates provide evidence of millennial scale climate variability and the chironomid community responded to rapid climate changes ostracodes were found in the late glacial and early holocene but disappeared due to chemical changes of the lake associated with changes in vegetation on the landscape inferred mean july air temperature total annual precipitation and water depth indicate a long term cooling with increasing moisture from the late glacial through the holocene during the younger dryas 12 9 11 2 ka cold and dry conditions prevailed the early and mid holocene were warm and dry with cool wet conditions after 4 ka and warm dry conditions since the end of the little ice age

organic geochemistry in pennsylvanian tidally influenced sediments from sw indiana abstract tidal rhythmites are vertically stacked small scale sedimentary structures that record daily variations in tidal current energy and are known to overlie some low sulfur coals in the illinois basin tidal rhythmites from the pennsylvanian brazil formation in indiana have been analyzed sedimentologically petrographically and geochemically in order to understand the character and distribution of organic matter om preserved in an environment of daily interactions between marine and fresh waters the concentration of organic matter toc ranges from traces to 6 9 and sulfur rarely exceeds 0 1 in individual laminae angular vitrinite is the major organic matter type accounting for 50 90 of total om the c s ratio decreases as the vertical distance from the underlying coal increases a decreasing c s ratio coupled with decreases in pr ph pr n c17 ph n c18 ratios and a shift of carbon isotopic composition towards less negative values suggest an increase in salinity from freshwater in the mudflat tidal rhythmite facies close to the coal to brackish marine in the sandflat tidal rhythmite facies further above from the coal within an interval spanning one year of deposition toc and s values show monthly variability on a daily scale toc and s oscillations are still detectable but they are of lower magnitude than on a monthly scale these small scale variations are believed to reflect oscillations in water salinity related to tidal cycles

a revised late quaternary vegetation history of the unglaciated southwestern yukon territory canada from antifreeze and eikland ponds antifreeze pond was thought to contain the oldest record of continuous environmental change in the southwestern yukon we have revised the original interpretation of the vegetation history of antifreeze pond and this region based on new pollen stomate and macrofossil analysis along with 38 new accelerator mass spectrometry ams 14c dates from antifreeze pond and nearby eikland pond although the overall pattern of vegetation change is similar to the previously published antifreeze pond record our new analysis indicates that the timing of the major vegetation shifts is substantially different particularly during the late glacial and early holocene periods from 17 000 9000 cal years bp the original antifreeze pond record was thought to span a mid wisconsinan interstadial 30 000 cal years bp and the full glacial period our results however indicate that the material of mid wisconsinan age was likely deposited by slumping around the pond making interpretation of the paleoenvironment difficult

tracing the sources of strontium in karst groundwater in chongqing china a combined hydrogeochemical approach and strontium isotope groundwater quality in karst regions is largely controlled by natural processes and anthropogenic activities over the past 10 years dissolved sr and its radiogenic isotope 87sr 86sr were widely used to trace the sources of solutes in groundwater however there is little research about hydrogeochemistry and sr isotopic compositions of the karst groundwater in chongqing karst area in this paper thirty five representative karst groundwater samples were collected from different aquifers limestone and dolomite and various land use types hydrochemical types of karst groundwater in chongqing were mainly of the ca hco3 type or ca mg hco3 type the dissolved sr concentrations of the studied groundwater ranged from 0 57 to 15 06 mmol l and the 87sr 86sr varied from 0 70751 to 0 71627 the groundwater samples from different aquifers and land use types showed distinctive dissolved sr concentrations and 87sr 86sr the very positive relationship between ca sr and mg sr in dolomite and limestone aquifers suggests that ca mg and sr element come mainly from the release of carbonate rock under the groundwater rock co2 gas interaction according to the 87sr 86sr ratio the sr element in karst groundwater in chongqing was controlled by the weathering of limestone dolomite and silicate rock allogenic water in a non karst area the relationship 87sr 86sr versus sr2 k na shows that the anthropogenic inputs also obviously contribute to the sr contents the research results show that the karst groundwater in chongqing is facing serious crisis of water quality and needs to be protected further

the impact of water washing biodegradation and self heating processes on coal waste dumps in the rybnik industrial region poland abstract water washing biodegradation and self heating impacts on coal waste features were investigated on four sample sets fresh coal wastes sampled less than one week after dumping samples from gullies in coal waste dumps self heated material and bierawka river sediment mixed with coal coal waste particles rock eval pyrolysis petrography and gas chromatography mass spectrometry gc ms were applied to assess degree of organic matter alteration it was found that water washing and self heating did not influence the vitrinite reflectance rock eval pyrolysis results better reflected the secondary changes in organic matter namely s 2 toc and hi t max allowed their extent to be defined changes were noted in other geochemical e g n alkane parameters 2 1 increased and n c 23 n c 31 decreased whereas pr ph pr n c 17 and ph n c 18 ratios increased slightly compared to fresh coal waste the hunt diagram allows discrimination between water washed and biodegraded samples from unaltered fresh coal waste similarly changes in distributions of phenols alkyl aromatic hydrocarbons and polycyclic aromatic hydrocarbons pahs reflect degree of water washing self heating strongly affects distributions of some biomarkers such as n alkanes pr and ph whereas pentacyclic triterpane distributions were generally well preserved phenols occur in greatest amount in self heated wastes probably released from heated vitrinite domination of 2 3 ring pah rings indicated the bitumen precipitation zone and well differentiated burnt out wastes recent organic matter input is seen in increased cpi carbon preference index values

carbon isotopic compositions of 28 30 bisnorhopanes and other biological markers in a monterey crude oil abstract an immature tar like oil api 3 13 c 23 6 vs pdb from the miocene monterey formation offshore california was selected for a study of carbon isotopic signatures of individual biomarkers the three principal stereoisomers of 28 30 bisnorhopane c 28 have within analytical precision identical carbon isotopic compositions average 13 c 32 3 0 4 and are considerably depleted in 13 c compared to the whole oil these 28 30 bisnorhopanes bnh differ isotopically from c 29 and c 30 17 h hopanes 25 8 and 26 1 and c 31 c 35 extended hopanes 13 c 27 7 and suggest different precursors for the c 28 hopanes than for c 29 c 35 hopanes the relative depletion of bnh of almost 9 compared to the isotopic composition of the whole oil suggests that these hopanes derive from chemoautotrophic bacteria possibly not yet identified h 2 s oxidizers which utilize 13 c depleted substrates the c 29 and c 30 hopanes are within analytical precision isotopically identical 26 and similar to algal derived compounds e g c 27 steranes 25 9 which is consistent with a cyanobacterial source for these hopanes an archaebacterial biomarker 1 1 biphytane 13 c 25 5 likely derived from methanogens is also isotopically similar to c 27 sterane norpristane pristane and phytane liberated by desulfurization of the aromatic and polar maltene fractions show isotopic compositions similar to the same isoprenoids in the free lipids of the bitumen total range from 24 5 to 27 5 this isotopic similarity supports a common origin for the free and sulfur bound forms of these isoprenoids this origin could be algal and or archaebacterial lipids which both show isotopic compositions within the range of the c 18 c 20 isoprenoids like other marine derived organic matter this monterey oil does not show the strong 13 c depletion typical for methylotroph derived compounds characteristically found in organic matter of lacustrine origin this may indicate fundamental differences of methane recycling processes in marine sulfate dominated as compared to lacustrine environments

geochemical characterisation and genetic origin of oils and condensates in the south viking graben norway abstract geochemical analysis of oil and condensate samples from all major fields and discoveries in the norwegian south viking graben as well as source rock extracts of upper and middle jurassic source horizons was carried out to characterise reservoired hydrocarbons and establish genetic relationships the south viking graben is in a mature phase of exploration and this study aims at unravelling regional trends to improve predictions in exploration and will show the significance of the play models in the area seven hydrocarbon families have been identified based on interpretation of molecular and isotopic characteristics and multivariate analysis of biomarker data these families can be linked to three source horizons three families originate from different facies of the draupne formation and are characterised by pr ph ratios below 2 dominance of c 27 regular steranes over the c 29 homologues and carbon isotopic values for saturate and aromatic fraction lighter than 28 and 27 respectively the upper jurassic heather formation and the middle jurassic vestland group each source one group of hydrocarbons typical for heather sourced hydrocarbons are elevated pr ph ratios between 2 35 and 3 08 low ratios of c 27 c 29 regular steranes and average isotopic values of 28 4 13 c sat and 26 8 13 c aro hydrocarbons from a middle jurassic source are characterised by very heavy isotopic composition highest pr ph ratios of the data set and dominance of c 29 regular steranes over the c 27 homologues among other factors the two remaining families represent mixtures from upper and middle jurassic sources and are mainly encountered in the greater sleipner area the available data in this study allowed characterisation of 84 of the recoverable oil resources which proved that the main source rock in the area is the upper jurassic draupne formation the play concept including a draupne source and tertiary reservoir proves to be most prolific with 239 10 6 s m 3 of recoverable oil equalling 88 of the total characterised oil resources oils in these tertiary reservoirs are however likely to be affected by biodegradation based on the available data the zone of biodegradation in the south viking graben appears to be limited to depths above 2140 m and temperatures below 70 c

geochemistry of dissolved and suspended loads of the seine river france anthropogenic impact carbonate and silicate weathering this study focuses on the chemistry of the seine river system one of the major rivers in europe and constitutes the first geochemical investigation of both suspended and dissolved loads of this river the seine river drains a typical mesozoic cenozoic sedimentary basin the paris basin constituted of limestones mixed or interbedded with terrigenous sediments derived from the paleoreliefs bordering the mesozoic and cenozoic seas in the context of quantifying the global influence of carbonate and silicate weathering on atmospheric co2 consumption the seine river offers the possibility of examining weathering rates in a flat sedimentary environment under temperate climatic conditions one of the major problems associated with the seine river as with many temperate rivers is pollution we propose in this paper 2 approaches in order to correct the dissolved load of the seine river for anthropogenic inputs and to calculate weathering rates of carbonates and silicates the first uses the dissolved load of rivers and tries to allocate the different solutes to different sources a mixing model based on elemental ratios is established and solved by an inversion technique the second approach consists in using the suspended load geochemistry under steady state conditions we show that the geochemistry of suspended sediments makes it possible to estimate the amount of solutes released during the chemical weathering of silicates and thus to calculate weathering rates of silicates the total dissolved load of the seine river at paris can be decomposed into 2 of solutes derived from natural atmospheric sources 7 derived from anthropogenic atmospheric sources 6 derived from agriculture 3 derived from communal inputs and 82 of solutes derived from rock weathering during high floods the contribution of atmospheric and agriculture inputs predominates the weathering rate of carbonates is estimated to be 48 t km2 yr 25 mm 1000 yr only 10 of carbonates are transported in a solid form the rest being transported in solution co2 consumption by carbonate weathering approaches 400 103 mol km2 yr in the seine river at paris about 2 3 mg l of dissolved cations are found to originate from the chemical weathering of silicates by taking dissolved silica into accounts the total dissolved load derived from silicate weathering is about 6 7 mg l this value is minimal because biological uptake of silica probably occur in the seine river the chemical weathering rate of aluminosilicates is estimated to be 2 t km2 yr the ratio of physical over chemical weathering of silicates range between 1 and 3 and the total chemical and physical erosion rates of sedimentary silicates are about 2 3 mm kyr the co2 consumption by silicate weathering 15 24 103 mol km2 yr and is independent of dissolved silica concentration silicate consumption is thus 20 times less than carbonate consumption in the paris basin compared to the neighboring granitic areas the sedimentary region drained by the seine river has 2 to 3 times lower co2 consumption rates we attribute this difference to the cation depleted nature of the seine basin aluminosilicates which are of sedimentary origin at a world scale the chemical denudation rates found for the seine basin are very low and comparable to those given for tropical lowland rivers draining silicates such as the rivers of the congo and amazon basins in spite of huge climatic differences we attribute this similarity to the low mechanical denudation that characterizes these two types of regions

strontium isotope geochemistry of groundwaters and streams affected by agriculture locust grove md the effects of agriculture on the isotope geochemistry of sr were investigated in two small watersheds in the atlantic coastal plain of maryland stratified shallow oxic groundwaters in both watersheds contained a retrievable record of increasing recharge rates of chemicals including no3 cl mg ca and sr that were correlated with increasing fertilizer use between about 1940 and 1990 the component of sr associated with recent agricultural recharge was relatively radiogenic 87sr 86sr 0 715 and it was overwhelming with respect to sr acquired naturally by water rock interactions in the oxidized non calcareous portion of the saturated zone agricultural groundwaters that penetrated relatively unoxidized calcareous glauconitic sediments at depth acquired an additional component of sr from dissolution of early tertiary marine caco3 87sr 86sr 0 708 while undergoing o2 reduction and denitrification ground water discharge contained mixtures of waters of various ages and redox states two streams draining the area are considered to have higher 87sr 86sr ratios and no3 concentrations than they would in the absence of agriculture however the streams have consistently different 87sr 86sr ratios and no3 concentrations because the average depth to calcareous reducing denitrifying sediments in the local groundwater flow system was different in the two watersheds the results of this study indicate that agriculture can alter significantly the isotope geochemistry of sr in aquifers and streams and that the effects could vary depending on the types sources and amounts of fertilizers added the history of fertilizer use and groundwater residence times

occurrence and distribution of sulfur in peat forming environments of southern florida abstract cores and surface samples of peats from the everglades mangrove region of southern florida were analyzed for total sulfur and pyritic sulfur these values were compared with the petrographic botanical components of the peats as determined from point counts of oriented microtome sections pyrite occurs as individual euhedral crystals loosely packed framboids and lenses or crusts of minute crystals framboids and minute crystals are often associated with organic matter and sometimes with bacteria and fungi pyrite tends to selectively occur in void spaces in or between peat tissues in samples containing very small amounts of pyrite framboidal pyrite is the prevalent form marine to brackish peats contain the highest pyrite and total sulfur contents with brackish peats generally containing more pyrite than marine peats pyrite tends to be lower in all peats within 30 cm of the surface whether marine or brackish burial of freshwater peats beneath marine or brackish peats tends to increase the total sulfur and pyritic sulfur in the underlying peats burial beneath brackish water clay rich deposits such as splays tends to increase total sulfur and pyritic sulfur in the underlying deposits more than burial beneath less clay rich deposits

examining suspended sediment sources and dynamics during flood events in a drained catchment using radiogenic strontium isotope ratios 87sr 86sr soil erosion is recognized as one of the main processes of land degradation in agricultural areas high suspended sediment loads often generated from eroding agricultural landscapes are known to degrade downstream environments accordingly there is a need to identify suspended sediment sources and to investigate their dynamics here soil and sediment strontium isotopic ratios were used to examine suspended sediment sources and dynamics in a lowland drained catchment in france suspended sediment n 14 was collected in stream and at tile drain n 4 outlets during three flood events between december 2013 and february 2014 potential source soils n 28 representative of the carbonate and silicate substrates found in the catchment were sampled and analyzed strontium isotopic ratios 87sr 86sr were measured in different particle size fractions 2 m 63 m and 2 mm soil 87sr 86sr ratios significantly discriminated between source samples classified as carbonate 0 712625 to 0 717815 and silicate 0 719287 to 0 724631 soils 87sr 86sr ratios measured in suspended sediment 0 713660 to 0 720571 reflect variations in source contributions during different hydrological conditions the 87sr 86sr ratios varied in the different fractions of soil samples i e 2 m 63 m and 2 mm and in suspended sediment samples suspended sediment was interpreted as a mixture of two end members with the dominant contribution of the 2 m fraction of soil samples occurring during small scale flood events and the 2 mm fraction during more intense flood events modelling results indicate that carbonate source soil contributions are variable with their highest contributions occurring during the two first flood events compared to the last flood event the results also show that the tile drainage system enhances the connectivity between cultivated hillslopes and the river network providing a preferential pathway for fine 2 m particles this study demonstrates the potential of using strontium isotopic ratios to examine the variations of suspended sediment sources in drained catchments with contrasting carbonate and silicate sources more importantly the results highlight the need to improve the management of sediment exported from tile drains in similar agricultural environments as they were demonstrated to transfer very fine material to the riverine environment

endostromatolites from permafrost karst yukon canada paleoclimatic proxies for the holocene hypsithermal a remarkable biogenic calcite precipitate forms carpets of finely laminated 1 mm diameter columns lining fissures within limestone bedrock in the permafrost regions of the northern yukon this material endostromatolite for its laminated morphology and growth hidden within the carbonate rock is ubiquitous within limestone terrains of the arctic and grew during the early holocene hypsithermal dissolution on the interior fissure faces is accompanied by biomineralization of the opposing faces a previously unrecognized weathering process in permafrost regions occurrence is restricted to outcrops with a southern orientation in permafrost regions in this case from the ogilvie mountains northern yukon growth occurs in water saturated talik during periods of permafrost degradation during insolation maxima their enriched 13c values 1 7 to 11 4 are generated in a methanogenic environment during anaerobic degradation of soil derived organic carbon a paleotemperature signal extracted from the 18o

hydrochemistry and isotope geochemistry of the upper danube river abstract the upper danube river and 19 of its major tributaries were monitored for 1046 km downriver and seasonally for ca mg sr na k hco3 co2 cl po4 sio2 no3 no2 nh4 so4 13cdic 18oh2o dh2o 34sso4 18oso4 and 87sr 86sr hydrological considerations and 18o d data show that the water balance in the river particularly after its confluence with the inn is controlled by the southern tributaries draining the mesozoic carbonate complexes of the alps as a result chemical balance at bratislava is mostly a conservative product of its tributaries the concentrations of ca mg and sr in the danube are 6 to 9 times higher than in pristine rivers although all these cations are derived from dissolution of mesozoic carbonates the ultimate cause is likely the enhanced generation of soil co2 due to agricultural and forestry practices dissolution of triassic sulfates is an additional factor for ca enrichment in the headwater section of the river dissolved sulfate with a comparable enrichment factor to that of alkaline earths appears to be derived mostly from atmospheric deposition a proposition based on consideration of its sulfur and oxygen isotopic compositions na k and cl are enriched by a factor of 2 5 to 4 times mostly as a result of industrial and municipal pollution sources in contrast to the above components which behave mostly conservatively during the downriver flow of the danube biogenic elements such as nutrients and si are influenced by in river processes the photosynthesis respiration balance that impacts the carbon cycle and the oxygen balance has been discussed elsewhere pawellek and veizer 1994 no3 no2 and nh4 are enriched by a factor of 10 to 16 times from point and diffuse sources along the watercourses generating at times downflow nitrification plumes from nh4 to no3 po4 varies seasonally chiefly as a result of biologic demand during the warm periods for sio2 the biological uptake mostly for secretion of diatom frustules combined with the deficiency of this compound that results from the predominantly carbonate lithology of the catchment results in concentrations that are below those of pristine rivers overall the present day salted characteristics of the river are chiefly a consequence of the long habitation history of the upper danube watershed

sedimentology of the changuinola peat deposit organic and clastic sedimentary response to punctuated coastal subsidence an extensive peat deposit on the caribbean coast near changuinola panama has developed in an area subject to periodic earthquake driven coseismic subsidence thick low ash low sulfur peat is accumulating immediately behind an aggrading and prograding barrier system and adjacent to a flood prone sediment laden river measurements of changes in local sea level as a result of a recent april 1991 earthquake reveal 30 50 cm of subsidence greatest at the southeastern extent of the study area where the peat surface is submerged to a depth of 3 m beneath the shallow waters of almirante bay transgression is proceeding from southeast to northwest parallel to the trend of the coast and the long axes of both the peat deposit and the major sand bodies in the eastern part of the deposit the effects of sea level rise are evident in the degree of humification mineral matter and sulfur content of mangrove and back mangove peats offshore and immediately adjacent to the marine margin and in peats associated with brackish tidal channels that drain the deposit however most of the deposit shows no indications of marine influence even though 40 of the peat is below present sea level the western section of the deposit has evolved from low lying palm swamps which originated in swales on the barrier bar into an oligotrophic bog plain with a water table elevated 6 75 m above sea level as the mire evolved transitions in vegetation resulted in transitions in peat types highly humified forest swamp and palm swamp peats underlie and surround well preserved fibric sedge peats and create a partial hydrological bounding surface that restricts subsurface drainage from the central bog the high water table and elevated topography of the mire and the low permeability and erosion resistance of the dense woody peat effectively insulate most of the deposit from both clastic influx and the extensive intrusion of rising marine waters it is evident that thick peat and hence coal deposits can accumulate due to tectonically driven punctuated subsidence without leaving a record of high clastic input within the peat even immediately adjacent to environments of active clastic deposition

insights from the salinity origins and interconnections of aquifers in a regional scale sedimentary aquifer system adour garonne district sw france contributions of δ34s and δ18o from dissolved sulfates and the 87sr 86sr ratio abstract the multi layered eocene aquifer is a regional scale sedimentary aquifer system occupying 120 000 km 2 within the adour garonne district france local authorities have recently identified the aquifer as being at risk from extensive irrigation abstractions threatening the sustainability of this key resource because large water abstractions for human activities can significantly influence the natural functioning of such aquifer systems e g with leakage between aquifer layers which can lead to water quality degradation the characterization of such large systems constitutes a key point to protect and prevent further deterioration of aquatic ecosystems this study provides further insight on this large aquifer through a geochemical approach which addresses the limited number of groundwater wells where sampling is possible for that purpose a geochemical analysis combining two isotope systems 34 s so4 18 o so4 and 87 sr 86 sr has been applied the eocene sedimentary aquifer system detrital to carbonate deposits is made up of four aquifer layers eocene infra molassic sand early eocene middle eocene and late eocene and has a mineralized area north of the aquitaine basin where groundwater shows strong mineralization and anomalous levels of critical substances so 4 f etc increasing the difficulty of resource exploitation the extreme heterogeneity of the geochemical composition of the groundwater between the aquifers and within a single aquifer is discussed in terms of the lithological control induced by the lateral variation of facies and interconnections between aquifer layers geochemical tools especially the 34 s and 18 o from dissolved sulfates and the 87 sr 86 sr ratio suggest that evaporite dissolution both sulfate and halite is the main process controlling the high salinity levels observed in the groundwater explaining the spatial variations observed at the aquifer system scale isotopic tools also provide new information regarding the interconnections between aquifer layers supporting the hypothesis that the eocene aquifer system integrates groundwater from the oligocene miocene aquifer through leakage effects these new insights will likely help decision makers adjust their choices when managing quality problems in particular in the mineralized area of the entre deux mers where targeted groundwater wells used for drinking water display anomalous levels of critical substances

regional atmospheric circulation change in the north pacific during the holocene inferred from lacustrine carbonate oxygen isotopes yukon territory canada analyses of sediment cores from jellybean lake a small evaporation insensitive groundwater fed lake provide a record of changes in north pacific atmospheric circulation for the last 7500 yr at 5 to 30 yr resolution isotope hydrology data from the southern yukon indicate that the oxygen isotope composition of water from jellybean lake reflects the composition of mean annual precipitation 18op recent changes in the 18o of jellybean sedimentary calcite 18oca correspond to changes in the north pacific index npi a measure of the intensity and position of the aleutian low al pressure system this suggests that 18op variability was related to the degree of fractionation during moisture transport from the gulf of alaska across the st elias mountains and that holocene shifts were controlled by the intensity and position of the al following this model between 7500 and 4500 cal yr b p long term trends suggest a predominantly weaker and or westward al between 4500 and 3000 cal yr b p the al shifted eastward or intensified before shifting westward or weakening between 3000 and 2000 cal yr b p rapid shifts eastward and or intensification occurred 1200 and 300 cal yr b p holocene changes in north pacific atmospheric circulation inferred from jellybean lake oxygen isotopes correspond with late holocene glacial advances in the st elias mountains changes in north pacific salmon abundance and shifts in atmospheric circulation over the beaufort sea

residence time of chalk groundwaters in the paris basin and the north german basin a geochemical approach the comparative geochemical and isotopic study of confined and unconfined chalk groundwaters of the paris basin and the n german basin proves a significant chemical evolution during groundwater flow from the recharge zones to the deep confined aquifer different time dependent geochemical parameters have been tested as dating tools cation ratios sr2 ca2 mg2 ca2 n no 3 noble gas contents as paleotemperature indicators ne ar kr xe radiogenic he 13c 14c 18o 2h 3h cation ratios and 13c show the importance of incongruent dissolution processes in the chalk aquifer water rock interactions were taken into account in a multi step dissolution model to determine radiocarbon groundwater ages the oldest waters in the confined part of the paris basin chalk with maximum 14c ages of 14 000 a b p contain pleistocene recharge components as can be shown by a stable isotope depletion and noble gas temperatures significantly lower than in recent groundwaters chalk waters at the lagerdorf site in northern germany show a distinct stratification with respect to residence times and hydrochemistry

a stable carbon isotope and biological marker study of polish bituminous coals and carbonaceous shales abstract biological marker and carbon isotopic compositions of coals and carbonaceous shales from the upper carboniferous strata of the upper silesian uscb lower silesian lscb and lublin lcb coal basins were determined to assess depositional conditions and sources of the organic matter n alkane sterane and isoprenoid distribution and carbon isotope ratios are consistent with an origin from higher plants in some cases pristane phytane pr ph ratios of carbonaceous shales roof and floor shales are 29 stereoisomers typical but not conclusive of higher plant origin carbonaceous shales exhibit a wider range of sterane composition suggesting local significant input of algal organic matter significant amounts of benzohopanes and gammacerane are present in some coals although benzohopanes are present at least in small amounts in samples from many different environments they have been reported to occur most commonly in marine environments the present study seems to provide the first example where benzohopanes have been reported in significant amounts in terrestrial organic matter gammacerane is abundant in rocks or sediments deposited in carbonate or highly saline marine environments the finding of high gammacerane concentrations in the coals expands the depositional settings in which it has been observed and questions its utility as an independent indicator of hypersaline carbonate environments stable carbon isotope composition of coals and type iii kerogen in carbonaceous shales as well as correlation of stable carbon isotope composition of saturated and aromatic hydrocarbons in carbonaceous shales from both the uscb and the lscb indicate terrigenous origin bitumens are always co genetic with associated coals and kerogens isotopic data reveal that sofer s genetic classification of oils is not applicable to organic matter in coals

geochemical study on a well in the western canada basin relation of the aromatic distribution pattern to maturity of organic matter abstract thirty one rock samples from a western canada basin well have been analysed for aromatics using glass capillary gas chromatography with simultaneous flame ionization and sulfur selective flame photometric detection a uniform aromatic distribution pattern with a marked predominance of di and tricyclic aromatic hydrocarbons was observed throughout a depth interval of 3000 meters comprising cretaceous and jurassic sediments the very high relative abundance of sulfur aromatics at two narrow intervals in the triassic and mississippian is attributed to a major change in facies gradual changes with increasing depth have been observed for a series of compound ratios which had been calculated from the isomers of methyl and dimethylphenanthrene and their parent compounds these changes reflect the increasing thermal maturation of the sedimentary organic matter a methylphenanthrene index mpi has been introduced which exhibited a very good correlation with vitrinite reflectance data the mpi is the first maturity parameter which is based on a series of aromatic hydrocarbons this hydrocarbon internal maturity parameter permits the recognition and definition of maturity levels in extracts which can be compared to the maturity e g vitrinite reflectance of source rocks

evidence for slowly changing 87sr86sr in runoff from freshwater limestones of southern france abstract 87 sr 86 sr ratios have been determined in modern rivers and freshwater limestones dating from 65 ma to the present over an area extending from the pyrenees to the massif central southern france about 40 ma ago the alpine mountain range of the pyrenees was strongly uplifted by the alpine orogenic activity and its pre hercynian basement dominated by schists gneisses and granites was rapidly exposed from beneath its blanket of mesozoic marine limestones meanwhile the 87 sr 86 sr ratio of the rivers has remained remarkably constant in both space with the exception of the very few northernmost samples and time in this area extreme variations through the orogenic period are small with 87 sr 86 sr lying between 0 7073 and 0 7084 at 55 65 ma and 0 7077 0 7096 for the last 30 ma river sr is controlled by a nearly binary mixing of silicate 3 4 and 1 4 end members with negligible influence of evaporites it is inferred that the silicate sediment contribution ratio of the world average rivers to seawater sr changes at a very slow rate even taking major basaltic events into account does not alter this conclusion as their contribution to the river sr is very subordinated to other components it is inferred that the seawater 87 sr 86 sr secular main trend over the phanerozoic is controlled by hydrothermal alteration of oceanic basalts and slow variation of the limestone silicate contribution ratio to the riverine sr oceanic events changes in organic productivity and carbonate compensation depth ccd may produce intense short term variations but recovery of steady state seawater 87 sr 86 sr is delayed by 40 80 ma through diagenetic sr remobilization in carbonate sediments

pollen representation source area and basin size toward a unified theory of pollen analysis abstract the concepts of pollen source area and of production and dispersal biases in pollen representation are quantified by means of a simple theoretical model source areas and relative pollen representation are shown to depend on basin size according to functions that describe the amount of pollen remaining airborne at increasing distances from single pollen sources the form of these functions is determined by physical processes standard formulas for elevated sources do not apply but the integrated form of sutton s equation for particle dispersal from a ground level source gives useful approximations applicable to pollen transport over a forest canopy simulations using this equation yielded source areas that increased realistically with basin size showed substantial differences between source areas for pollen grains with different deposition velocities and predicted that lighter pollen grains should become better represented with increasing basin size all of these predictions are qualitatively consistent with present knowledge of the characteristics of pollen assemblages in different depositional environments the model further allows parameters that can be estimated by statistical calibration methods to be predicted from underlying physical quantities this extension suggests procedures for testing the theory with quantitative data on surface pollen and forest composition preliminary results showed reasonable agreement between estimated and predicted values of dispersal indices for the most abundant taxa in pollen spectra from the northern midwestern united states

response of the porcupine and old crow rivers in northern yukon canada to holocene climatic change a major aggradation took place from 8000 bp to 4000 bp in the porcupine and old crow rivers northern yukon the aggradation was a consequence of an increase in flow and the result of a perturbation of the permafrost active layer following the early holocene climatic warming of northwestern canada these findings are useful for improving our understanding of how natural landscapes and river systems evolved in regions that experienced a permafrost history and more particurlarly an increase in climatic warming this article also contributes to an improved understanding of natural landscape evolution along the porcupine and old crow rivers in eastern beringia where there has been much interest in questions related to animal and human migration and adaptation

holocene environmental history of the aishihik region yukon canada a 2 7 m sediment core from wa01 a small pond in southwest yukon canada unofficial name 61 14 41 n 136 55 35 w 1000 m above sea level documents the postglacial vegetation and climate history of the aishihik basin open birch shrub tundra established at the site ca 10 900 cal years bp immediately after deglaciation picea glauca established ca 10 200 cal years bp and an open spruce forest ecosystem has since remained dominant on the landscape a gradual increase in alnus crispa starting ca 6600 cal years bp has also been noted in other studies from central yukon suggesting a significant climate transition in yukon at this time an alternating pattern in sediment loss on ignition also beginning ca 6600 cal years bp may be broadly related to trends in 18o values from the mount logan and jellybean lake oxygen isotope records and is most likely reflective of periodic changes in available moisture in the region resulting from alterations in the strength and position of the aleutian low press

drowning of a nearshore peat forming environment atane formation cretaceous at asuk west greenland sedimentology organic petrography and geochemistry abstract the cretaceous atane formation nuussuaq basin west greenland is dominated by non marine sandstones shales coals and delta front deposits marine incursions are frequent however and near asuk disko a coal seam is encased in shallow marine deposits notable changes in both petrography and geochemistry occur through the seam at the base and top of the seam the proportions of inertinite and liptinite increase at the expense of the huminite maceral group and within all maceral groups proportions of detrital macerals increase geochemical changes include systematic variations in toc ts n alkane acyclic isoprenoid aromatic hydrocarbon and di and triterpenoid biomarkers which include a number of rearranged hopanes and hopenes and six isomers of 28 30 bisnorhopane the variations reflect diagenetic changes related to the availability of clay as well as changes in depositional environment going from shallow marine conditions through fresh water mire back to open water conditions and to the eventual return of shallow marine conditions shown by the occurrence of delta front deposits containing ophiomorpha nodosa trace fossils c 50 cm above the top of the coal seam

a late quaternary paleotemperature record from hanging lake northern yukon territory eastern beringia abstract the late quaternary paleoclimate of eastern beringia has primarily been studied by drawing qualitative inferences from vegetation shifts to quantitatively reconstruct summer temperatures we analyzed lake sediments for fossil chironomids and additionally we analyzed the sediments for fossil pollen and organic carbon content a comparison with the 18 o record from greenland indicates that the general climatic development of the region throughout the last glaciation holocene transition differed from that of the north atlantic region between 17 and 15 ka mean july air temperature was on average 5 c colder than modern albeit a period of near modern temperature at 16 5 ka total pollen accumulation rates ranged between 180 and 1200 grains cm 2 yr 1 at 15 ka approximately coeval with the bolling interstadial temperatures again reached modern values at 14 ka nearly 1000 yr after warming began betula pollen percentages increased substantially and mark the transition to shrub dominated pollen contributors chironomid based inferences suggest no evidence of the younger dryas stade and only subtle evidence of an early holocene thermal maximum as temperatures from 15 ka to the late holocene were relatively stable the most recognizable climatic oscillation of the holocene occurred from 4 5 to 2 ka

tertiary deltaic and lacustrine organic facies comparison of biomarker and kerogen distributions abstract biological marker and kerogen compositional data in tertiary deltaic and lacustrine settings were compared and contrasted the two settings are represented by a coals and organic carbon rich shales in a ick deltaic sequence from the far east constituting three distinct organic facies and b humic coals and spropelic oil shales in a restricted intermontane freshwater lacustrine sequence from western montana u s a constituting two distinct organic facies wedistinguish the organic facies in each depositional setting by systematic differences in gross compound class distributions kerogen and infrared spectral characteristics molecular character of pyrolyzates sterane carbon number distribution and sterane hopane ratios the kerogens of the three deltaic organic facies are characterized by varying quantities of vitrinite resinite sporinite cutinite and fluorescent amorphinite triterpane distributions reveal numerous terrigenous compounds including oleanane oleanenes and unidentified c 30 presumably resin derived components the two organic facies of the freshwater lacustrine setting are distinguishedased upon either a vitrinite or an alganite fluorescent amorphinite predominance in the kerogen numerous characteristics facies related markers are also present including dehydroabietane land plant resins and 4 methylsteranes perhaps from freshwater dinoflagellate input the available molecular and petrographic data are evaluated and characteristics are proposed for distinguishing five organic facies of these two depositional settings the successful simultaneous use of molecular geochemistry and organic petrography in this study provides a format for refining the organic facies concept

hydrocarbon potential of middle and upper devonian coals from melville island arctic canada abstract some of the oldest coals in the world are found within the middle to upper devonian clastic wedge of the canadian arctic archipelago the coals investigated here occur in the weatherall hecla bay and beverly inlet formations on western melville island and range in age from late givetian to middle frasnian many of these coals are rich in liptinite macerals particularly sporinite and hence can be termed canned coals both elemental and rock eval analysis indicate these coals have the potential to generate liquid hydrocarbons a good correlation between liptinite with both h c or hydrogen index is observed up to about 50 liptinite after which the latter two parameters level off the coals range in maturity from 0 61 to 0 87 r o and hence should be in the oil window the amounts of hydrocarbons that can be extracted from the coals when expressed in mg g organic carbon are very low suggesting that they are poor source rocks for oil all the extracts except for the most mature and vitrinite rich sample show high pr ph ratios and biomodal n alkane distributions a cannel coal from the beverley inlet formation has a very unusual triterpane distribution that includes regular ab ring desmethyl and ab ring methyl hopanes steranes are in very low concentrations compared to hopanes in all samples the relative abundance of c 28 and c 29 steranes appears to be influenced by maceral composition hydrous pyrolysis at 330 c for 72 h generated greater amounts of hydrocarbons from the coals suggesting they could be the source of liquid hydrocarbons at greater maturities the hydrous pyrolysis experiments also indicate that thin walled spores are more reactive than thick walled spores at lower temperatures the coals on melville island are not thought to be significant source rocks for the oil and gas occurrences in this area of the canadian arctic because they make up only a very small fraction of the total sedimentary package

distribution of forms of sulfur in peats from saline environments in the florida everglades abstract although there is published information on the mechanism of sedimentary pyrite formation resulting from bacterial reduction of sulfate little is known about the distribution of forms of sulfur including organic in peats in order to increase understanding of the geochemistry of sulfur in coals we have determined distributions of forms of sulfur in five cores of saline peat and one of brackish peat all from areas near the shark river and whitewater bay in the coastal swamps of south florida all concentrations vary widely with depth total sulfur concentrations range up to 6 of dry solids minor amounts of sulfur are present as h2s s0 so42 and acid soluble sulfide but the principal forms are usually pyritic and organic the ratio organic pyritic is highly variable but at a majority of levels in a profile is considerably greater than unity it is inferred that topochemical factors are important in determining the distribution of sulfur forms in any element of volume

holocene debris flows and environmental history hazelton area british columbia debris flow deposits of chicago creek and the sediment pollen and macrofossil records of seeley lake were studied to elucidate the holocene history of the northwest flank of the rocher dcboulc range near hazelton british columbia the chicago creek drainage has experienced numerous rockfalls debris slides and debris flows a large debris flow covering approximately 300 ha occurred about 3580 2 150 bp this flow was two to three orders of magnitude larger than historic debris flows in this drainage it traveled about 3 km down chicago creek and dammed the outlet stream of seeley lake a debris deposit along lower chicago creek is interpreted as the product of debris torrents that formed during or soon after the damming of seeley lake its surface exhibits soil development rubification and profile development comparable to that on the large debris flow suggesting equivalent age pollen and plant macrofossils are described from a core taken in seeley lake this core spans the period from ca 9200 bp to the present a disturbance event in 3380 2 110 bp correlative with the large chicago creek debris flow is recorded by a clastic sediment layer and changes in the microfossil and rnacrofossil assemblages the chicago creek debris flow and debris torrent ca 3500 bp may be the catastrophic event recorded in the story of the medeek an oral history or ada ok of the gitksan people of hazelton

interaction between different water bodies in a small catchment in the paris basin brevilles france tracing of multiple sr sources through sr isotopes coupled with mg sr and ca sr ratios abstract intensive monitoring of the cuise sands aquifer in a small agricultural catchment 3 km2 where agricultural practices are well documented over nearly 5 a showed significant disparities for major element concentrations sr concentrations isotopic compositions and 3h values depending on the groundwater sampling locations lower 87sr 86sr values 0 7079 0 7085 associated with low no 3 concentrations low mg sr molar ratios 0 7085 and higher mg sr molar ratios 250 suggest a contribution of sr from anthropogenic sources strontium isotopes coupled with mg sr and ca sr ratios of groundwater in this catchment successfully demonstrated the capacity to trace fertilizer contributions which significantly modify the natural sr isotopic signature of groundwater the specific geochemical signature of groundwater revealed by sr isotopes in addition to major and trace element concentrations in particular mg sr and ca sr molar ratios demonstrated the partial isolation of groundwater bodies in this catchment compartmentalisation of the aquifer is compatible with fault distribution as defined by geological and geophysical investigations thus the sr isotopic tool coupled with mg sr and ca sr ratios has been applied with success to trace water pathways and recharge and to provide scenarios for the hydrological functioning of the system

discrimination between different water bodies from a multilayered aquifer kaluvelly watershed india trace element signature in the multilayered aquifer of kaluvelly india comprising various sedimentary layers overlying a charnockitic basement concentrations of trace elements were measured in aquifer formations and in groundwaters to identify geochemical tracers for water bodies the two main sandstones cuddalore and vanur originate from the charnockites and the cuddalore sandstone has experienced lateritization in the studied area two charnockite end members were identified a dioritic and a granitic one mineralogical composition and whole rock ti concentrations confirmed the charnockite which displayed the granitic composition as the parent rock of the two sandstones titanium distribution indicates that the cuddalore sandstone originates from a more intense weathering of the parent material than the vanur sandstone despite extensive differences in trace element contents recorded in aquifer formations only a few trace elements were suitable to distinguish the water bodies among soluble elements li in the vanur aquifer and ba in the charnockite and carbonaceous aquifers can be used as tracers as the input of these elements in solution is mainly regulated by the available stock for a given mineralogical origin there is a direct link between the aquifer formation composition and water signature with the exception of as concentrations of redox sensitive elements were not preserved during pumping because of oxidation preventing their use as tracers low mobility elements such as la ce th zr nb hf or ta were too insoluble to be detected in waters and or to record the aquifer formation signature their input in solution was not regulated by the available stock but by the dissolution rate of rock forming minerals only ti can be used to distinguish between two out of the three aquifers charnockite and vanur the specific behavior of ti recorded in these waters may be linked to rutile inclusions within plagioclases and to the influence of climate on ti solubility

tracking selenium in the chalk aquifer of northern france sr isotope constraints groundwater at the southern and eastern edges of france s paris basin has a selenium content that at times exceeds the european framework directive s drinking water limit value of 10 g l to better understand the dynamics of the chalk groundwater being tapped to supply the city of lille and the se origins we used a combination of geochemical and isotopic tools strontium isotopes coupled with ca sr mg sr and se sr ratios were used to identify the main groundwater bodies and their mixings with the mg sr ratio constraining a ternary system groundwater in the agricultural aquifer recharge zone represents a first end member and displays the youngest water ages of the catchment along with the highest strontium isotopic signature 0 7084 and low se contents anaerobic groundwater constitutes a second major end member affected by water rock interactions over a long residence time with the lowest strontium isotopic signature 0 7079 and the lowest se content its low sf6 content confirming the contribution of old water se rich groundwater containing up to 30 g l of se represents a third major end member with an intermediate sr isotopic ratio and is mainly constrained by the clayey se rich formation overlying the chalk aquifer the spatial and temporal se variability in the groundwater is clearly linked to the presence of this formation identified as tertiary and also to the hydrological conditions saturation of the se rich clays by oxygenated groundwater enhances se mobility and also sr adsorption onto the clays this multi tool study including sr isotopes successfully identified the se origins in the aquifer and has led to a better understanding of the regional mixing and processes affecting the chalk groundwater

dendroclimatic reconstruction of summer temperatures in northwestern canada since a d 1638 based on age dependent modeling abstract ring widths from five picea glauca stands at the alpine treeline in northwestern canada are used to investigate climate growth responses and to develop a long reconstruction of summer temperatures response function and linear regression analyses indicate that the radial growth response of these trees to climate varies with age and site at most sites the period of significant positive response to growing season temperatures declines with tree age age dependent and standard age independent models are then used to develop two reconstructions of june july temperatures for northwestern canada extending back to a d 1638 calibration statistics were similar for both models but the standard model performed poorly during verification the reconstruction produced using age dependent modeling suggests june july temperatures were cooler than present throughout most of the past 350 years with the exception of the late 18th century particularly cool periods occurred at 1700 and in the mid 19th century in constast the standard model suggests that temperatures were similar to or warmer than present during the last 350 years the age dependent reconstruction compares favorably with other proxy climate records from northern north america age dependent dendroclimatic modeling can provide a sensitive record of recent climatic change that allows the inclusion of previously rejected sites into dendroclimatic analyses

improved age estimates for the white river and bridge river tephras western canada new 14c ages date the eruptions that produced the white river and bridge river tephras two important holocene marker beds in western canada the 14c ages were obtained on trees in growth position buried in coarse tephra and a pyroclastic flow near the source vents the mean calendric age of the white river eruption based on four 14c ages is 1147 cal years bp calibrated years approximately equivalent to calendric years or ad 803 the 2 age range obtained from the two most precise 14c ages is 1014 1256 cal years bp or ad 694 936 the mean age of the bridge river eruption determined both from i the single most precise outer ring 14c age and ii the weighted mean of six outer ring 14c ages is 2360 cal years bp or 411 bc 2 age range 2349 2704 cal years bp or 755 400 bc