changes of the lignite seam architecture a case study from polish lignite deposits abstract the architecture of a lignite seam is not only of great cognitive importance but it is also important for the planning and exploitation of lignite therefore this paper presents the factors that had or could have an impact on the deformation of lignite seams all the currently extracted lignite seams in poland of the early and middle miocene age have been considered their development as indicated by the thickness from a few to nearly 250 m was controlled by intensive subsidence during deposition of the peat reaching a maximum of more than 700 m most cases that are theoretically possible were supported by data from boreholes and observations in existing opencast mines both surfaces bounding the lignite seam that is bottom and roof were taken into account the following factors could impact on the formation of the bottom of the lignite seam the paleotopography before the development of peat mires and syn and post depositional tectonics on the other hand the roof of the lignite seam could be deformed by such geological processes as the post depositional tectonics post depositional erosion and compaction the causes of changes in the bottom of the lignite seam deformations are relatively easy to explain in contrast the causes of the roof of the lignite seam irregularities are still poorly understood in the latter case often overlooked or underestimated is the impact of compaction with maximum sizes ranging up to 450 m in fact the compaction of peat lignite often plays a major role in the folding of the roof of the lignite seam

strontium isotopes as indicators of mineral weathering in catchments determination of the 87sr 86sr ratio in rain water stream water soils and rocks in two scottish catchments has provided useful information on mineral weathering over a period of 26 months the 87sr 86sr ratio in rain water had mean values of 0 7095 and 0 7098 n 12 whereas stream water had mean values of 0 7080 n 16 in catchment in devonian andesites with strontium isotope ratios of 0 7117 0 7232 in the rocks and soils and 0 7184 n 16 in catchment of cambrian metamorphic rocks with strontium isotope ratios of 0 7360 0 8218 in the rocks and soils respectively the mineralogy consists predominantly of varying proportions of quartz plagioclase feldspar and k feldspar with some mica and chlorite the fact that the 87sr 86sr ratios in the stream in the andesitic catchment are lower than for the rain water probably indicates preferential weathering of plagioclase feldspar releasing 86sr rather than k feldspar and mica which contain greater amounts of 87sr the 87sr 86sr ratio acts as a tracer for the origin of the solutes in the stream water long term monitoring of the strontium isotope ratio in stream water could be a potential means of detecting relative changes in soil weathering rates due to environmental change

the strontium isotopic evolution of marcellus formation produced waters southwestern pennsylvania abstract the production of natural gas and natural gas liquids from unconventional tight shale formations involves hydraulic fracturing and subsequent removal of fluids co produced with the gas the chemistry of the returning fluid reflects the original composition of the injection water mobilized constituents in the shale formation and co mingled formation waters liberated by hydraulic fracturing produced water from unconventional gas wells tapping the middle devonian marcellus formation is characterized by high total dissolved solids tds including very high strontium concentrations in this study the strontium isotope composition 87 sr 86 sr was measured in produced waters from four horizontally drilled hydraulically fractured marcellus shale gas wells in southwestern pennsylvania sampled from the first day after commencement of flowback to as much as 27 months later the 87 sr 86 sr of the waters tended to change rapidly over the first few days of water return and then approached but did not reach a constant range of values from 0 7113 to 0 7114 which appears to be characteristic of this part of the marcellus play in contrast the concentration of sr rose more slowly and appeared to hit a steady state value up to 3000 mg l by the end of the first year taken together with results from earlier work these data suggest mixing between injected frac fluid and high tds formation water highly enriched in sr and isotopically relatively uniform throughout the marcellus shale gas play this brine could exist within porous lenses of organic matter in the shale in pre existing fractures within the shale and or originate from fluids that migrated from adjacent formations at some point during the post depositional history of the basin

carbonate versus silicate weathering in the raikhot watershed within the high himalayan crystalline series the major element and sr isotope geochemistry of surface waters bedrock and river sands was investigated in the raikhot watershed within the high himalayan crystalline series hhcs in northern pakistan mass balance calculations of mineral weathering contributions to the dissolved flux of ions from the watershed indicate that 82 of the hco 3 flux is derived from the weathering of carbonate minerals and only 18 is derived from silicate weathering even though the bedrock is predominantly quartzofeldspathic gneiss and granite with only 1 carbonate in the watershed this study demonstrates the importance of trace amounts of bedrock carbonate in controlling the water chemistry of glacial watersheds we suggest that the flux of sr with a high 87 sr 86 sr ratio in the major himalayan rivers may be derived in large part from weathering of trace amounts of calcite within the largely silicate hhcs models that use the flux of radiogenic sr from the himalayas as a proxy for silicate weathering rates may therefore overestimate the amount of co 2 consumption due to silicate weathering in the himalaya

strontium isotope record of paleohydrology and continental weathering eocene green river formation wyoming sr isotope ratios in carbonate rich lacustrine strata provide highly resolved and geo graphically specific records of past changes in weathering and regional drainage patterns the eocene green river formation is perhaps the best documented pre quaternary la custrine unit in the world therefore these strata are ideally suited for studying the be havior of sr the 87 sr 86 sr ratios measured for primary carbonate in lake expansion contraction cycles of the laney member are directly linked to changing lake facies four distinct cycles are preserved in a 6 4 m interval of the arco washakie basin no 1 core each represented by a vertical succession of transgressive stromatolite facies containing dolomicritic intraclasts laminated micrite facies deposited during lake highstands and lake marginal dolomicrite facies which represent subsequent lowstands initial 87 sr 86 sr ratios range from 0 711 99 to 0 713 31 the least radiogenic isotope compositions are as sociated with laminated micrite that records increased regional runoff from phanerozoic marine carbonate and tertiary volcanic rocks during lacustrine highstands the most radiogenic isotope compositions are associated with dolomicrite recording a higher pro portion of runoff from basin bounding precambrian uplifts and the exposed lake plain during lacustrine lowstand the observed 87 sr 86 sr variations may also be due in part to changes in differential weathering of the surrounding landscape where drier climates are associated with decreased differential weathering and therefore higher 87 sr 86 sr in runoff

the strontium isotope budget of the warta river poland between silicate and carbonate weathering and anthropogenic pressure abstract the sr isotope composition 87 sr 86 sr and sr content of waters of the warta river central western poland and its tributaries were used to fingerprint water sources and their interactions in space and time dissolved sr in river water of the warta is characterized by a relatively narrow range of the 87 sr 86 sr values from 0 7090 to 0 7105 which contrasts with a strong variation in isotopic signatures of the tributaries from 0 7080 to 0 7121 with the exception of three streams which include inputs of mine waters the waters of tributaries are more enriched in 87 sr than the master stream the overall sr budget of the warta watershed is determined by the relative contributions of carbonate dissolution and silicate weathering it can be accounted for by mixing between waters from three reservoirs 1 groundwater charged with sr through interaction with sr bearing clay minerals 2 groundwater related to weathering dissolution of carbonate rocks and 3 atmospheric waters charged with sr from the near surface weathering and wash out of quaternary glaciogenic deposits superimposed on the natural sr isotope systematics is impact of mine waters and fertilizers the former providing non radiogenic sr from the permian mesozoic aquifers constitutes an important anthropogenic element of the sr budget whereas the impact of the latter is presumably common but of minor importance the present day sr isotope systematics of the warta is temporary and different from that of the pre industrial times

strontium isotopes and rubidium in the ganga brahmaputra river system weathering in the himalaya fluxes to the bay of bengal and contributions to the evolution of oceanic87sr 86sr the concentrations of rb and sr and87sr 86sr isotopic ratios have been measured in the dissolved load of the ganga brahmaputra g b river system the ganga was sampled extensively from its source at gangotri in the higher himalaya to patna on the alluvial plains the brahmaputra was sampled in its stretch in assam in india the average sr concentration in the ganga at patna is 1 2 mol l and that in the brahmaputra at goalpara is 0 73 mol l the mean87sr 86sr ratios are 0 7239 and 0 7192 respectively the87sr 86sr in the ganga source waters the alaknanda the bhagirathi and their tributaries range between 0 7300 and 0 7986 considerably higher than the global average runoff value of 0 7119 the high87sr 86sr in the ganga source waters result from the intense weathering of precambrian granites and gneisses enriched in radiogenic sr the sr isotope systematics of the ganga waters is dominated by silicate weathering whereas carbonate weathering plays a significant role in their major ion chemistry the g b system transports about 910 million moles of dissolved sr annually to the bay of bengal with an average87sr 86sr of 0 7213 the sr transported by the g b system is about 2 7 of the global dissolved sr flux to the oceans via rivers model calculations reveal that the g b system has contributed significantly to the sr isotope evolution of seawater during the past 20 ma the flux of rb through the g b system is 24 million moles per year this is about 5 of the global river supply of rb to the oceans nearly twice the contribution of water via the g b system to the oceans our study suggests that the marine geochemistries of sr and rb and possibly u may have been influenced considerably by the himalayan orogeny

soil organic carbon pools in the northern circumpolar permafrost region of all soils in the northern permafrost region is approximately 18 782 10 3 km 2 o r approximately 16 of the global soil area in the northern permafrost region organic soils peatlands and cryoturbated permafrost affected mineral soils have the highest mean soil organic carbon contents 32 2 69 6 kg m 2 here we report a new estimate of the carbon pools in soils of the northern permafrost region including deeper layers and pools not accounted for in previous analyses carbon pools were estimated to be 191 29 pg for the 0 30 cm depth 495 80 pg for the 0 100 cm depth and 1024 00 pg for the 0 300 cm depth our estimate for the first meter of soil alone is about double that reported for this region in previous analyses carbon pools in layers deeper than 300 cm were estimated to be 407 pg in yedoma deposits and 241 pg in deltaic deposits in total the northern permafrost region contains approximately 1672 pg of organic carbon of which approximately 1466 pg or 88 occurs in perennially frozen soils and deposits this 1672 pg of organic carbon would account for approximately 50 of the estimated global belowground organic carbon pool

strontium isotope compositions of river waters as records of lithology dependent mass transfers the garonne river and its tributaries sw france the relation of lithology in the drainage basin to the dissolved load of the garonne river and its main tributaries in southwestern france was evaluated by determining 87sr 86sr ratios and concentrations of major and trace elements during a 2 year long survey in the upper drainage basin the garonne river waters were isotopically varied at two observation points 0 71131 0 00030 2 for 84 18 ppb 2 and 0 71272 0 00044 for 86 10 ppb respectively in the lower drainage basin the garonne river waters were isotopically identical at three observation points at 0 71020 0 00024 for 125 22 ppb by contrast the tributaries lot truyere aveyron arriege gers and salat are widely varied in their 87sr 86sr ratios and sr concentrations from 0 70836 0 00049 to 0 71058 0 00057 and from 18 8 to 280 116 ppb the sr isotope ratios and concentrations suggest a dominant supply of two reservoirs of sr one of which is with low 87sr 86sr ratios and high sr contents that is typically characteristic of carbonate rocks and the other with high 87sr 86sr ratios and low sr concentrations that is characteristic of felsic rocks locally as in the lot waters draining the massif central and within the pyrenees mountains a third source of sr from mafic rocks may be involved mass balance calculations based on the mean 87sr 86sr ratios and contents of the dissolved sr and on the mean discharges integrating the 2 year survey suggest that contribution of the silicate reservoir amounts 3 8 of the total dissolved sr flux mass balance calculations also suggest that variation in the supply of sr from either of the two major reservoirs does not exceed the analytical uncertainty at about 5 the 87sr 86sr ratios of hcl and nh4cl leachates of suspended loads of the garonne river are different from that of the associated dissolved sr this leaching related supplementary sr represents less than 10 of the total amount of sr transported by the garonne waters the sr isotope characteristics of the leachates are probably records of an intermediate pedogenic episode in the weathering erosion process occurring in the garonne drainage basin

sr isotopes in natural waters applications to source characterisation and water rock interaction in contrasting landscapes strontium isotopes 87sr 86sr are routinely measured in hydrochemical studies to determine sources and mixing relationships they have proved particularly useful in determining weathering processes and quantifying end member mixing processes a number of routine case studies are presented which highlight that sr isotopes represent a powerful tool in the geochemists toolbox helping to constrain weathering reactions weathering rates flow pathways and mixing scenarios differences in methodologies for determining the weathering component in natural environments inherent differences in weathering rates of different minerals and mineral heterogeneity often cause difficulties in defining the weathering component of different catchments or aquifer systems nevertheless sr isotopes are useful when combined with other hydrochemical data to constrain models of water rock interaction and mixing as well as geochemical processes such as ion exchange this paper presents a summary of recent work by the authors in constraining the sources of waters and weathering processes in surface catchments and aquifers and indicates cases where sr isotopes alone are insufficient to solve hydrological problems

soil geomorphology and frozen ground conditions at a subalpine talus slope having permafrost in the eastern swiss alps at a subalpine site with permafrost below the timberline in the eastern swiss alps the complex interrelationship between different environmental factors was investigated by applying an integrated approach that combines soil mapping 3d near surface geophysics and surface and subsurface temperature monitoring the objectives of this approach were to explore the 3d extension of isolated permafrost bodies and to relate this to surface parameters such as soils and humus forms and other extrinsic factors using this procedure interdependencies between surface soil properties and humus forms and subsurface factors ground thermal regime and frozen ground conditions could be independently analysed although time consuming 3d eri electrical resistivity imaging demonstrated its ability for precise permafrost mapping despite climate warming super cooling in winter along the investigated scree slopes is still efficient enough for establishing permafrost conditions by comparing the spatial dimensions of the permafrost bodies with surface conditions we found that thick moss or organic litter layers had an insulating effect and prevented the permafrost from melting however the comparison of soil units and soil thickness with the permafrost distribution did not always show an obvious relationship this indicates that there is a complex evolution and behaviour of soils and permafrost at such sites

controls over the strontium isotope composition of river water abstract strontium concentrations and isotope ratios have been measured in river and ground waters from the ganges orinoco and amazon river basins when compared with major element concentrations the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments 1 1 typical drainage basins containing limestones evaporites shales and alumino silicate metamorphic and igneous rocks 2 2 shield terrains containing no chemical or biogenic sediments and 3 3 the floodplains that constitute the largest areas of many large rivers the strontium concentration and isotope composition of river waters are largely defined by mixing of strontium derived from limestones and evaporites with strontium derived from silicate rocks the strontium isotope composition of the limestone endmember generally lies within the phanerozoic seawater range which buffers the 87 sr 86 sr ratios of major rivers a major exception is provided by the rivers draining the himalayas where widescale regional metamorphism appears to have led to an enrichment in limestones of radiogenic strontium derived from coexisting silicate rocks the strontium isotope systematics of rivers draining shield areas are controlled by the intense transportlimited nature of the weathering reactions and thereby limits variations in the strontium flux from these terrains floodplains are only a minor source of dissolved strontium to river waters and precipitation of soil salts in some floodplains can reduce the riverine flux of dissolved strontium to the oceans the most effective mechanisms for altering the isotope ratio and flux of riverine strontium to the oceans are increased glaciation and large scale regional metamorphism of the type produced during continental collision both mechanisms provide a means for increasing the 87 sr 86 sr ratio of the global riverine flux

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

strontium isotopic composition of the po river dissolved load insights into rock weathering in northern italy abstract strontium isotopic composition 87sr 86sr of river water provides insight on the nature of rocks involved in the weathering processes and important constraints for reconstructing silicate versus carbonate weathering in large scale basins new data presented in the context of a geochemical map of the po river basin highlight that the po river water evolves from the upper part of the catchment where 87sr 86sr approaching 0 7097 relates to the weathering of igneous and metamorphic silicate rocks to the middle part where less radiogenic compositions 87sr 86sr 0 7089 are driven by the confluence of the tributaries draining mesozoic carbonate rocks of the south alpine domain and from inflow of apennine streams characterized by less radiogenic sr signatures due to weathering of marly sediments and mafic magmatic rocks down flow the sr isotopic compositions of po river water rises at 0 7091 either by the confluence of the last apennine tributary panaro 87sr 86sr 0 7095 and or by the possible contribution from hyporheic exchanges po river isotopic signatures reveal slightly more radiogenic 87sr 86sr in comparison to other important alpine river systems e g danube rhine and rhone likely suggesting that silicate rocks are comparatively contributing more weathering byproducts in the po basin

temporal variations in sr and 87sr 86sr of the ganga headwaters estimates of dissolved sr flux to the mainstream the headwaters of the ganga the alaknanda bhagirathi and the ganga were analysed for their dissolved major ions sr and 87sr 86sr on a biweekly to monthly basis over a period of one year to determine their temporal variations and the factors contributing to them the concentrations of major ions and sr show significant seasonal variation with lower values during monsoon period in all the three rivers a similar trend is also observed for 87sr 86sr and na ca na narclr suggesting relatively lower contribution of sr and na from silicates which are more radiogenic in sr during monsoon budget calculations show that silicate derived dissolved sr srs in the river ganga alaknanda and the bhagirathi varied from 10 4 to 27 11 7 3 to 30 12 16 6 to 57 23 of measured sr respectively with lower values during monsoon the relative decrease in silicate erosion compared to carbonate during monsoon can result from several factors these include higher dissolution kinetics of the carbonates lower water rock interaction time and availability of larger area for weathering the annual discharge weighted sr flux derived from the time series data is higher by 20 from that based on peak flow sr and lower by 40 compared to that derived from lean flow sr concentration the area normalized annual flux of dissolved sr from the ganga at rishikesh is about five times its flux at rajshahi bangladesh and a few other major global rivers such as the amazon indicating higher erosion rate over the himalaya copyright 2010 john wiley sons ltd

changes of groundwater chemistry caused by the flooding of iron mines czestochowa region southern poland abstract underground mining always causes disturbances of the hydrogeological environment primarily due to the dewatering of mine workings the flooding of abandoned mines contributes to the rebound of the cone of depression developed previously but it also leads to significant pollution of groundwater in the mined areas the middle jurassic aquifer in the czestochowa region of the flooded iron mines has been investigated with respect to patterns of water movement and groundwater chemistry basing on eight years of studies including field measurements data collection and physicochemical analyses of groundwaters two models has been developed a hydrological model of water flow and a hydrochemical speciation model additionally in order to validate the results stable isotopes of hydrogen and oxygen together with tritium and radiocarbon have been analysed four distinct hydrochemical zones has been identified within this aquifer based on the results of these studies zones i and ii where the groundwater is influenced by iron mining and zones iii and iv where the groundwater in the middle jurassic aquifer is uncontaminated the results indicate that the changes in groundwater chemistry within the flooded iron mines area are significant maximum so 4 2 contents reach 1103 0 mg l 1 and are 6 times higher than the acceptable levels for human consumption of water polish drinking water limits mn 2 contents reach 6 61 mg l 1 and are 70 times higher and fe tot reach 271 4 mg l 1 and are 500 times higher water flow modelling and hydrogeochemical interpretations suggest that waters in the zone iii in spite of their occurrence within the area of the cone of depression caused by the iron mining are not influenced by the polluted mine waters this is corroborated by the isotopic investigations the age of waters from this zone has been determined as early holocene which strongly suggests that these waters had recharged before the dewatering began the results of the hydrochemical studies suggest that fifteen years after the flooding waters stored in the mine workings may be defined as quasi stagnant middle jurassic aquifer water supplies located in czestochowa are not polluted by mine waters today but the predicted contamination of waters will occur in the first supplies at the end of the 21st century however it may last for 300 500 years the general conclusion is that if the formation of the polluted acid and neutral waters in such mined sedimentary ores as in the czestochowa region is not prevented the residual pollution of groundwaters in the flooded mines may persist for several centuries

the use of strontium and lead isotopes to identify sources of water beneath the fresh kills landfill staten island new york usa abstract a study was undertaken to explore whether the isotopic compositions of pb and sr are useful to distinguish mixtures of uncontaminated groundwater seawater and landfill leachate at the fresh kills landfill staten island new york ratios of 87sr 86sr ranged from 0 7088 to 0 7137 and could be used to distinguish sr that was derived from seawater from that in uncontaminated groundwater lead isotopic abundances did not vary systematically among the different water sources plots of 87sr 86sr versus dissolved organic c b and nh4 defined perpendicular trends documenting where leachate or sea water mixed with uncontaminated groundwater and demonstrating that leachate has not contaminated groundwater in aquifers beneath the landfill

chemical dynamics of the st lawrence riverine system δdh2o δ18oh2o δ13cdic δ34ssulfate and dissolved 87sr 86sr chemical and stable isotope analyses of the st clair detroit niagara and st lawrence rivers st lawrence system and their tributaries show that the chemical and isotopic compositions of the waters are strongly controlled by the geology of their drainage basins tributaries draining the canadian shield have very low tds hco3 so42 ca2 mg2 no3 sr2 higher si and fetotal and high 87sr 86sr ratios 0 710 0 713 the grand and thames rivers that drain paleozoic limestones dolostones and evaporites are characterized by opposite attributes the st lawrence and the tributaries draining the canadian appalachians fall between these two endmembers the st clair detroit and niagara rivers do not show any pronounced seasonal variations in major component chemistry due to buffering by the great lakes in contrast pronounced seasonal variations characterize the lower st lawrence mainly because of significant tributary inputs into the overall water budget the d and 18o in the st lawrence range from 60 9 to 44 5 and from 8 5 to 6 1 smow respectively much heavier than the comparative values measured for the tributaries 92 8 to 58 3 and 13 1 to 8 5 this is a consequence of evaporative loss that over the residence time of water of 102 years equals about 7 of the water volume in the great lakes the strontium and sulfur isotopic values for the st lawrence system are relatively uniform with measured values from 0 70927 to 0 71112 for 87sr 86sr and from 4 3 to 5 6 for sulfate 34s their seasonal variations are also minor the strontium and sulfur fluxes of the st lawrence river are calculated to be 7 84 108 and 1 09 1011 mol a respectively the relative contributions of the great lakes tributaries and other sources to these fluxes are 73 16 11 for strontium and 64 13 23 for sulfur isotopic composition of dissolved inorganic carbon 13cdic in the st lawrence system ranges from 4 7 to 0 7 considerably heavier than the values for the tributaries 16 5 to 6 7 the light 13cdic values for the tributaries suggest that co2 from bacterial respiration plays an important role in the isotopic composition of riverine dic however in the main stem river s this bacterial signal is masked by isotopic equilibration with atmospheric co2 due to the long residence time of water in the great lakes seasonally the main stem river s have heavier 13c values in the fall than in the spring a consequence of preferential 12c consumption by photosynthetic plants in the epilimnion of the great lakes during the growth season in the down stream portion of the st lawrence river influx of isotopically light tributary waters causes progressive 13c depletion from 1 3 to 2 0 and 1 4 to 3 0 in the fall and spring respectively the total dic carbon flux of the st lawrence river is calculated to be 3 9 1011 mol a mass balance calculations show that the relative contributions of the great lakes tributaries decay of organic matter exchange with the atmosphere and dissolution of carbonates to this total dic flux are 81 13 2 6 10 in the spring and 83 15 2 4 0 in the fall respectively

tectonic evolution of the mid polish trough modelling implications and significance for central european geology abstract the polish basin forms the easternmost part of the permian mesozoic northwest european basin the depocentral axis of the polish basin the mid polish trough mpt is superimposed on the boundary between the west european phanerozoic and east european proterozoic crustal domains within the trans european suture zone the presence of this fundamental crustal boundary may be paramount in structurally controlling the position of the mpt concentrating stresses during post variscan wrench and extensional tectonics in central europe tectonic subsidence analysis of the preserved and reconstructed stratigraphic record of the polish basin indicates the occurrence of an initial late permian early triassic 255 241 ma rifting phase that was followed by subsequent episodes of increased tectonic subsidence during the oxfordian kimmeridgian 157 152 ma and beginning in the cenomanian 97 ma the oxfordian kimmeridgian episode is interpreted as corresponding to a second extensional event which correlated with intersified rifting and wrench activity within the arctic north atlantic rift system and along the northern tethyan margin while the cenomanian may be considered a precursor of compressional deformations in the basin which culminated in basin inversion in the latest cretaceous and paleocene forward modelling results in view of existing geophysical interpretations which show the presence of a deep moho and a very velocity lower crustal layer beneath thempt suggest that permo mesozoic basic development may be related at least in part to the intrusion of mantle material into and densification of the lower crust rather than exclusively to crustal extension and thinning

a strontium isotopic study of mineral and surface waters from the cezallier massif central france implications for mixing processes in areas of disseminated emergences of mineral waters abstract surface and mineral waters from a geothermal area cezallier in the centre of the massif central france were analysed for sr isotopes sr and major elements in order to use sr isotopes to investigate the discharge of a mineralised water area especially in the case of disseminate mineralised water emergences the 87 sr 86 sr ratios of mineralised waters ranged from 0 715541 to 0 716773 the variation in 87 sr 86 sr values was small for the 5 mineral springs sampled over two periods 5 10 6 14 10 6 regarding the reproductivity of the 87 sr 86 sr ratio measurements no differences can be seen and the 87 sr 86 sr ratio of mineral waters can be considered to be constant with time the 87 sr 86 sr ratios of surface waters collected along the zagat river ranged from 0 705303 to 0 715091 the lowest values were always observed in the headwaters the difference in the 87 sr 86 sr ratios between the two sampling periods was 22 10 4 and can be related to the hydrological situation low or high flow the 87 sr 86 sr ratios of surface waters collected in the drain ranged from 0 715072 to 0 716585 the difference in the 87 sr 86 sr ratios between the two sampling periods is 11 10 4 for the drain headwaters and 13 10 5 at the outlet of this area likewise these variations can also be related to the hydrological situation plots of 87 sr 86 sr vs 1 sr ratios show two distinct binary mixing trends and the existence of at least four end members a mixing parameter f giving the proportions of the two components can be estimated for assumed 87 sr 86 sr ratio and sr content values of the pure end members an estimate of the mineral water discharge can be calculated using the results of the mixing model and the measured flow in the drain area the mixing model gives an estimate 0 5 1 l s 1 or 10 13 of mineral water in the total flow a similar calculation was done for the river where the mineral water flow was 0 96 l s 1 3 5 m3 h 1 100 m downstream from the bridge in april 1994 and 6 m3 h 1 20 m downstream from the bridge in september 1994

the sources and transport of sr and nd isotopes in the baltic sea we have determined the concentration and isotopic composition of sr and nd in waters from the baltic sea the baltic sea is an intracontinental stratified brackish water estuarine like system and the rivers emptying into it drain a suite of terranes ranging from proterozoic archean in the north to phanerozoic in the south the sampled brackish waters range in salinity from seawater sw at 35 289 to a minimum of 2 460 at the surface in the innermost part of the gulf of bothnia the sr concentrations show generally conservative behavior indicating a simple two component mixing however small deviations 3 70 from a perfect mixing line reveal that the imprints from rivers with different sr concentrations are preserved in the blending strontium concentrations from a depth profile across the redoxcline in the baltic proper indicate that vertical particle transport alters the sr concentration in the water our estimated concentration of sr in the average freshwater input to the baltic is 0 03 ppm which is only about 0 4 of the sw concentration the sr isotopic data range from e sr sw 0 in seawater to e sr bw sw 7 8 in the least saline baltic water bw sample in the gulf of bothnia the isotopic composition of sr versus 1 sr in the baltic sea follows an almost perfect mixing line which shows that seawater sr is mixed with much more radiogenic components calculated end member values of e sr sw for each sample show that the riverine input into the gulf of bothnia has e sr sw 120 200 and 10 50 e units in the baltic proper these values are in general agreement with direct measurements of river waters in each region however the calculated values in the gulf of bothnia are lower than the measured river water input in this region which indicates the presence of less radiogenic sr presumably originating from the river waters draining the southern part of the basin which are partially transported northward and mixed with sr from the gulf of bothnia rivers the nd concentration in the baltic sea is not conservative varying between 5 and 45 ppt with the highest concentrations in the bottom waters due to vertical particulate transport a plot of e nd o in baltic water yields a good correlation with the calculated freshwater end member e sr sw the data show that it is possible to unravel the different freshwater sources into the baltic and to identify the zones of particulate removal of both non conservative species such as the ree and of quasi conservative species such as sr the use of isotopic tracers in this estuarine environment may provide a much better insight into mixing and element transport it should also be possible to trace lateral movements of freshwater inputs

ca sr and sr isotope systematics of a himalayan glacial chronosequence carbonate versus silicate weathering rates as a function of landscape surface age we explored changes in the relative importance of carbonate vs silicate weathering as a function of landscape surface age by examining the ca sr and sr isotope systematics of a glacial soil chronosequence located in the raikhot watershed within the himalaya of northern pakistan bedrock in the raikhot watershed primarily consists of silicate rock ca sr 0 20 mol nmol 87 sr 86 sr 0 77 to 1 2 with minor amounts of disseminated calcite ca sr 0 98 to 5 3 mol nmol 87 sr 86 sr 0 79 to 0 93 and metasedimentary carbonate ca sr 1 0 to 2 8 mol nmol 87 sr 86 sr 0 72 to 0 82 analysis of the exchangeable carbonate and silicate fractions of seven soil profiles ranging in age from 0 5 to 55 kyr revealed that carbonate dissolution provides more than 90 of the weathering derived ca and sr for at least 55 kyr after the exposure of rock surfaces even though carbonate represents only 1 0 wt of fresh glacial till the accumulation of carbonate bearing dust deposited on the surfaces of older landforms partly sustains the longevity of the carbonate weathering flux as the average landscape surface age in the raikhot watershed increases the ca sr and 87 sr 86 sr ratios released by carbonate weathering decrease from 3 6 to 0 20 mol nmol and 0 84 to 0 72 respectively the transition from high to low ca sr ratios during weathering appears to reflect the greater solubility of high ca sr ratio carbonate relative to low ca sr ratio carbonate these findings suggest that carbonate weathering controls the dissolved flux of sr emanating from stable himalayan landforms comprising mixed silicate and carbonate rock for tens of thousands of years after the mechanical exposure of rock surfaces to the weathering environment copyright 2002 elsevier science ltd

geochemistry of the maroni river french guiana during the low water stage implications for water rock interaction and groundwater characteristics abstract the maroni river draining a basin of 60 000 km 2 and flowing down to the atlantic ocean between french guiana and surinam was studied during a low flow period using the chemical and isotopic composition of its dissolved load the dissolved concentrations of major ions cl so 4 no 3 hco 3 ca na mg k trace elements rb and sr stable isotopes o and d and strontium isotopes 87 sr 86 sr were determined on samples from the main stream of the river and its tributaries and from groundwaters collected in wells and two boreholes the total dissolved solid tds and the sum of cations agree with those summarised for the major guyanan rivers the orinoco and amazon on a tds vs na na ca diagram all the data from the maroni catchment plot in the precipitation dominance field close to the plots of the tefe and negro rivers the groundwaters collected from wells largely mimic the surface waters and may represent alluvial groundwater along the maroni terraces whereas the groundwaters collected from the boreholes show clearly higher values and reflect an increase in water rock interaction the river and groundwaters of the maroni catchment have been isotopically enriched 18 o vs 2 h through evaporation and the 18 o and 2 h can be used as mixing tracers of river waters within the catchment after corrections for rainwater addition were computed for selected elements and for 87 sr 86 sr ratios using chloride as an atmospheric input reference the water rock interaction along the maroni catchment was investigated for cations and sr isotopes

strontium isotope ratios in streams and the effect of flow rate in relation to weathering in catchments abstract in calculating catchment weathering rates using strontium isotope ratios one of the parameters required is the 87 sr 86 sr ratio of the streamwater the effect of flow rate on this ratio is not well understood with conflicting reports in the literature to provide more detailed information on the effect of flow rate on strontium isotope ratios the 87 sr 86 sr ratio was measured in streamwater samples taken at low and high flow rates and also in samples taken at four and eight hourly intervals during two rain events in a small catchment area 90 ha in andesitic lavas the 87 sr 86 sr ratio varied over a narrow range of 0 70797 to 0 70852 for a flow rate range of 6 1 to 41 51 s 1 and showed no relationship to flow rate weathering of non radiogenic plagioclase feldspar in the soils controls the isotope signature of the streamwater and the constancy of the ratio with flow rate indicates that 1 more radiogenic minerals such as k feldspar and mica do not contribute any more significantly during high flow than during low flow and 2 from the available information it is not necessary to take flow rate into account when using 87 sr 86 sr ratios in weathering studies in this particular catchment although it must be emphasized that this conclusion may not apply to other catchments the concentration of strontium in the streamwater was inversely proportional to the flowrate

internal structure and conditions of permafrost mounds at umiujaq in nunavik canada inferred from field investigation and electrical resistivity tomography a systematic approach was used for the interpretation of the electrical resistivity tomography carried out on two permafrost mounds at umiujaq in nunavik canada to assess their internal structure and conditions prior information under the form of a geocryologic model of the permafrost mounds was integrated in the inversion of the pseudo section of apparent electrical resistivity the geocryologic model was developed from the synthesis of previous field investigations including shallow and deep sampling temperature and electrical resistivity logging and cone penetration tests performed in the permafrost mounds values of electrical resistivity were ascribed to the different layers making of the geocryologic model to define a synthetic resistivity model of the permafrost mounds used as a reference model to constrain the inversion the constrained resistivity model clearly show the presence of ice rich cores in the permafrost mounds underscored by high resistivity values in excess of 30 000 m while t

strontium isotope variations in middle jurassic late bajocian callovian seawater implications for earth s tectonic activity and marine environments abstract strontium isotope ratios of well preserved belemnite rostra and ammonite shells are presented from stratigraphically well dated upper bajocian callovian sediments of the polish jura chain in central poland nekto benthic belemnites show a narrow trend of changes of 87 sr 86 sr ratio that are interpreted to record secular variations in the strontium isotope composition of seawater a new fit of the seawater strontium isotope curve for the late bajocian callovian is presented based on current and literature data the data show a gradual decrease of seawater 87 sr 86 sr ratio throughout the late bajocian earliest middle callovian lowest 87 sr 86 sr ratios 0 706850 and the flat minimum of the curve were reached in the latest middle and the late callovian the middle jurassic decrease in seawater 87 sr 86 sr ratio is interpreted to have been a result of the increased volcanic activity of the seafloor studied nektonic ammonites are considered to have lived in surface or shallow near coastal waters of the polish jura chain basin and been affected by the freshwater influx a slight enrichment of ammonite shells in 87 sr isotope is linked to a change in strontium isotope composition of the surface or near coastal waters due to the riverine strontium input