chemistry and origin of minor and trace elements in vitrinite concentrates from a rank series from the eastern united states england and australia abstract a rank series consisting of twelve vitrinite concentrates and companion whole coal samples from mined coal beds in the eastern united states england and australia were analyzed for c h n o ash and 47 trace and minor elements by standard elemental instrumental neutron activation analysis inaa and direct current arc spectrographic dcas techniques the reflectance of vitrinite atomic h c and o c and ash free carbon data were used to determine ranks that range from high volatile c bituminous coal to meta anthracite a van krevelen atomic h c vs o c diagram of the vitrinite concentrates shows a smooth curve having its lowest point at h c 0 18 and o c 0 01 this improves the van krevelen diagram by the addition of our vitrinite concentrate from meta anthracite from the narragansett basin of new england boron content 400 450 ppm in two illinois basin vitrinite concentrates was about an order of magnitude higher than b contents in other concentrates analyzed we attribute this to marine origin or hydrothermal activity the alkaline earth elements ca mg and ba dcas have higher concentrations in our vitrinite concentrates from bituminous coals of the appalachian basin than they do in vitrinite concentrates from the marine roofed bituminous coals of the illinois basin therefore a nonmarine origin for these alkaline earth elements is postulated for the appalachian basin coals an ion exchange mechanism due to high concentrations of these elements as ions in diagenetic water but probably not recent ground water may be responsible for the relatively high values of these elements in appalachian concentrates higher concentrations of ni and cr in one of the english vitrinite concentrates and of zr in the australian concentrate probably indicate organic association and detrital influence respectively

sea level estimates during the last deglaciation based on δ18o and accelerator mass spectrometry 14c ages measured in globigerina bulloides coupled measurements of 18o and accelerator mass spectrometry ams 14c in a particular species of planktonic foraminifera may be used to calculate sea level estimates for the last deglaciation of critical importance for this type of study is a knowledge of the seasonality of foraminiferal growth which can be provided by 18o measurements of modern shells core tops plankton tows isotopic 18o ams 14c dating and faunal records transfer function sea surface temperature were obtained from two cores in the north atlantic at about 37 n the locations were chosen to obtain high sedimentation rate records removed from the major ice melt discharge areas of the last deglaciation based upon globigerina bulloides data four 18o based sea level estimates were calculated 67 7 m at 12 200 yr b p and 24 8 m at about 8200 yr b p for core su 81 18 83 10 m at 12 200 yr b p and 13 11 m at about 8500 yr b p for core su 81 14 using a second working hypothesis concerning the seasonability of g bulloides growth it is suggested that the sea level rose by about 40 m during the millennium which followed 14 500 yr b p

thorium 230 profiling in deep sea sediments high resolution records of flux and dissolution of carbonate in the equatorial atlantic during the last 24 000 years variations in carbonate flux and dissolution which occurred in the equatorial atlantic during the last 24 000 years have been estimated by a new approach that allows the point by point determination of paleofluxes to the seafloor an unprecedented time resolution can thus be obtained which allows sequencing of the relatively rapid events occurring during deglaciation the method is based on observations that the flux of unsupported 230th into deep sea sediments is nearly independent of the total mass flux and is close to the production rate thus excess 230th activity in sediments can be used as a reference against which fluxes of other sedimentary components can be estimated the study was conducted at two sites ceara rise western equatorial atlantic and sierra leone rise eastern equatorial atlantic in cores raised from three different depths at each site from measurements of 230th and caco3 changes in carbonate flux with time and depth were obtained a rapid increase in carbonate production starting at the onset of deglaciation was found in both areas this event may have important implications for the postglacial increase in atmospheric co2 by increasing the global carbonate carbon to organic carbon rain ratio and decreasing the alkalinity of surface waters and possibly the north atlantic deep water increased carbonate dissolution occurred in the two regions during deglaciation followed by a minimum during mid holocene and renewed intensification of dissolution in late holocene during the last 16 000 years carbonate dissolution was consistently more pronounced in the western than in the eastern basin reflecting the influence of antarctic bottom water in the west this trend was reversed during stage 2 possibly due to the accumulation of metabolic co2 below the level of the romanche fracture zone in the eastern basin

unchanged nitrogen isotopic composition of organic matter in the south china sea during the last climatic cycle global implications the 15n of surface and down core sediments spanning the last 20 200 kyr from the entire south china sea scs ranges only from 3 0 to 6 5 with no correlation with discernible paleoclimatic oceanographic changes detailed profiles of the uppermost sediment column including fluff samples indicate a minor diagenetic overprint of 0 3 1 2 at the sediment water interface the absence of any correlation with reconstructed glacial interglacial changes in primary production terrigenous input and or sea level related basin configuration is attributed to a complete consumption of nitrate during primary production in this marginal basin during at least the last 140 000 years this in turn implies that the 15n of the nitrate used during primary production remained approximately constant during the last climatic cycle the proposed scenario infers an unchanged nitrogen isotopic composition of the western pacific subsurface nitrate between glacial and interglacial stages as well as during terminations and thus constrains proposed changes in the oceanic n inventory

200 000 yr diatom records from atlantic upwelling sites reveal maximum productivity during lgm and a shift in phytoplankton community structure at 185 000 yr abstract time series of diatom accumulation rates dar and assemblage composition for the last 200 000 yr from the atlantic major coastal upwelling loci of the eastern boundary currents and eastern equator are compared together with independent proxies of export production to upper ocean productivity and to nutrient concentration and utilization fluctuations in dar are concomitant at all sites and in good correspondence to the other independent productivity proxies indicating glacial periods as the most productive times of the past 200 000 yr in both hemispheres of the eastern atlantic maximum productivity about one order of magnitude higher than at present occurred at the last glacial maximum lgm despite the atlantic similarities in both coastal and equatorial upwelling types important regional and site specific variations emerge in the southern hemisphere site a contradiction of proxies diatoms and corg is noted at the base of stage 6 185 000 yr the good correlation found between the corg and the benthic foraminifera fluxes is interpreted as a reflection of a shift in the phytoplankton community structure related to either a change in the n p si ratio or similar nutrient conditions associated with increased water column stratification

trace elements in the lower pliocene fossiliferous kangal lignites sivas turkey abstract the kangal lignite basin which is one of the most productive lignite basins in eastern anatolia turkey includes two lignite seams containing abundant gastropoda shells in the lower pliocene kalburcayiri formation the seams are currently exploited in an open cast mine in the kalburcayiri field and supply feed coal to a power plant with 300 mw capacity the average thickness of each of the two seams in this mine is about 10 m and they are separated by about 20 m of tuffaceous sedimentary rocks a 15 20 cm thick tuff bed occurs within the upper seam the purpose of the study was to understand mineralogy and trace element concentrations of the two lignite seams in the kalburcayiri formation which were affected by volcanic ashes fifty nine core samples of the lignites from seven boreholes across the basin and eight channel samples from the working lignite seams were collected and analysed by proximate analysis x ray powder diffraction xrd inductively coupled plasma mass spectrometry icp ms and scanning electron microscopy sem with energy dispersive x ray microanalysis techniques the samples show that the worked lignite seams on an as received basis contain high moisture contents 43 4 57 8 all the samples on an air dried basis have high ash yields from 19 5 to 81 7 and a broad range of total sulfur contents from 1 16 to 7 04 and calorific values 684 to 4621 kcal kg except for two samples with no temperature rise due to high ash yield the mineral matter of the studied samples is made up of calcite quartz feldspar pyrite opal ct clay minerals gypsum and traces of aragonite the trace element analyses on a whole coal dry basis indicate that most of the borehole samples showed enrichment in specific elements including zn 15 1394 g g mo 13 368 g g and u 5 5 131 g g when compared to the range of these elements for most coals in the world the contents of zn mo and u for the samples from the worked lignite seams are respectively 38 187 54 161 and 28 55 g g the sem studies show that zn is hosted mainly in micron sized zn bearing mineral sphalerite but no mo and u bearing minerals have been detected during these studies except for monazites containing th and u traces the mo and u concentrations are negatively correlated with the ash yields and these elements are contained mainly within organic matter

surface sediment distribution along the chilean continental slope related to upwelling and productivity abstract the coastal upwelling system of the peru chile current belongs to the most productive regions in the world oceans in spite of this remarkable fact only very little is known about the sediment distribution in its southern part off the coast of chile to increase the knowledge about this region a multiparameter study of the surface sediment distribution along the chilean continental slope between 27 and 42 s has been carried out detailed analyses of sedimentary data toc and carbonate contents 13corg 15n of the species composition of planktic foraminifera and of the stable isotope composition of the two planktic foraminifera species neogloboquadrina pachyderma dex and globigerina bulloides reveal a close relation to environmental conditions in the region the pattern of a southward increase of surface water productivity known from satellite data is closely reflected in the organic carbon and 15n data information about the water mass distribution especially about varying influences of upwelling waters and warmer subtropical surface waters can be derived from the species composition of the planktic foraminifera while the stable isotope data provide additional clues about water mass characteristics high productivity along the chilean margin north of 40 s is sustained by coastal upwelling while further to the south advection of nutrients with the antarctic circumpolar current and a significant riverine input fuel the highest productivity found in the study area this data set will provide the base for future paleoclimatic and paleoceanographic reconstructions of the southeast pacific region

influence of lateral particle advection and organic matter degradation on sediment accumulation and stable nitrogen isotope ratios along a productivity gradient in the canary islands region abstract we compare total and biogenic particle fluxes and stable nitrogen isotope ratios 15n at three mooring sites along a productivity gradient in the canary islands region with surface sediment accumulation rates and sedimentary 15n higher particle fluxes and sediment accumulation rates and lower 15n were observed in the upwelling influenced eastern boundary region ebc compared to the oligotrophic sites north of gran canaria european station for time series in the ocean canary islands estoc and north of la palma lp the impact of organic matter degradation and lateral particle advection on sediment accumulation was quantified with respect to the multi year flux record at the estoc remineralisation of organic matter in the water column and at the sediment surface resulted in an organic carbon preservation of about 0 8 and total nitrogen preservation of about 0 4 of the estimated export production higher total and carbonate fluxes and accumulation rates in the lower traps and surface sediment compared to the upper traps indicated that at least 50 of the particulate matter at the estoc was derived from allochthonous sources low 15n values in the lower traps of the estoc and lp point to a source region influenced by coastal upwelling we conclude from this study that the reconstruction of export production or nutrient regimes from sedimentary records in regions with strong productivity gradients might be biased due to the mixture of particles originating from autochthonous and allochthonous sources this could result in an imprint of high productivity signatures on sedimentation processes in oligotrophic regions

organic matter preservation on continental slopes importance of mineralogy and surface area abstract theoretical considerations calculations and data reported by keil et al 1994a were used to assess the recent hypotheses that mineral surface roughness controls the specific surface area of continental margin sediments and that the matrix linked organic carbon content of continental margin sediments occurs as a monolayer or monolayer equivalent coating of organic compounds on the surfaces of detrital minerals and other detrital nonorganic grains mayer 1994 results of our analysis indicate that it is not the surface roughness of the terrigenous detrital framework grains that controls the specific surface area of most continental margin sediments even in the sand and silt fractions but rather the presence of nonspherical high surface area to volume particles primarily clays but also oxy hydroxides and ultra structured nonorganic bioclasts such as diatom frustules analysis of the mineralogy organic carbon content surface area and in situ microfabric of continental margin sediments off california in the mendocino and san luis obispo areas and off the state of washington indicate a strong correlation between the amount of matrix linked organic matter present and the suite of clay minerals data indicate that organic carbon appears to be preferentially sequestered in smectite rich sediments compared to those whose clay fractions are dominated by chlorite we suggest that this association is a function of differences in the site density and chemistry of the clays and differences in their flocculation behavior our data also indicate that organic carbon preservation on the three california transects all of which have a suboxic oxygen minimum zone that impinges on the sea floor is not significantly influenced by differences in bottom water oxygen concentration and carbon stable isotope data suggest no preferential preservation of continental organic matter over that of marine origin

carbonates and cementation of glacially derived cohesive soils in new york state and southern ontario cet article presente des resultats se rapportant a la teneur en carbonate de silts et d argiles naturels en fonction de la profondeur de l emplacement geographique et de l origine geologique on etudie aussi l influence de cette teneur en carbonate sur le comportement geotechnique l effet sur la pression de preconsolidation apparente est illustre en detail pour l un des sites etudies la repartition des carbonates a l interieur des varves d un depot glacio lacustre est egalement presentee pour demontrer la variabilite potentielle de la cimentation naturelle des sols les donnees en provenance de quinze sites etayent les relations proposees entre teneur en carbonate et pression de preconsolidation apparente

mid depth oxygen drawdown during heinrich events evidence from benthic foraminiferal community structure trace fossil tiering and benthic δ13c at the portuguese margin abstract the distribution of trace fossils and benthic foraminiferal assemblages in two sediment cores from 2160 m water depth at the northern and 1100 m at the southern portuguese continental margin was used to reconstruct the bottom water oxygenation during the last 40 ka emphasis was given to the heinrich events during which enhanced meltwater flux associated with the iceberg surges reduced or even halted deep water formation in the north atlantic condensed trace fossil tiering structures and high proportions of low oxygen tolerant benthic foraminifera suggest a major drawdown of bottom water oxygenation during heinrich events using the benthic foraminiferal oxygenation index bfoi of kaiho 1991 1994 that links benthic foraminiferal communities to ambient bottom water oxygenation we extracted apparent oxygen concentrations from benthic assemblages bfoi values suggest low oxic conditions during heinrich events 1 and 4 with mean oxygen levels of 2 6 to 2 8 ml l 1 and high oxic conditions with 4 1 ml l 1 during heinrich event 2 at the shallower site high proportions of low oxygen tolerant foraminiferal species and bfoi minima are recorded a few centimetres below the maximum concentrations of ice rafted debris indicating that the original microhabitat depth of dysoxic species is preserved beneath the heinrich layers even though bioturbation continued during the events trace fossil tiering calibrated with the redox boundary in low oxic environments and dysoxic ichnotaxa commonly associated with black shales indicate oxygen levels lower than those implied by the bfoi oxygenation estimates derived from trace fossil tiering denote low oxic conditions during h1 13 3 ka with oxygen concentrations slightly above 1 ml l 1 and dysoxic conditions during h2 20 6 ka h3 27 ka and h4 33 5 ka with oxygen concentrations between 0 1 and 1 ml l 1 during the younger dryas bottom waters likely were low oxic negative excursions of benthic carbon isotope values provide independent control on the oxygen drawdown during heinrich events considering a bottom water oxygenation of 6 1 to 6 5 ml l 1 during the last glacial the benthic 13 c minima reveal an oxygen depletion to values between 3 4 and 5 0 ml l 1 during h1 through h4 at the shallower core site differences between estimates from benthic 13 c bfoi and trace fossil tiering suggest that benthic foraminiferal communities are rather robust to oxygen depletion if the level does not fall below 3 ml l 1 whereas burrowing organisms react sensitively to depth variations of the redox boundary in near surface sediments due to even small changes of bottom water oxygenation

last glacial maximum paleoproductivity and water masses off nw africa evidence from benthic foraminifera and stable isotopes abstract last glacial maximum lgm paleoproductivity organic carbon c org fluxes and seasonality was reconstructed from benthic foraminiferal faunas and the stable carbon and oxygen isotopes of foraminiferal calcite sediments of the lgm between 23 000 to 19 000 cal yr bp of sixteen cores from the upwelling region off morocco between cape ghir 31 n and cape yubi 27 5 n were investigated four regions with distinct paleo c org fluxes and seasonality were reconstructed based on faunal assemblages and 13 c values of hoeglundina elegans 1 the cape yubi upwelling region with high paleoproductivity high paleo c org fluxes and very low seasonality as indicated by the bolivina albatrossi uvigerina mediterranea assemblage and lowest mean 13 c h elegans 2 the cape ghir upwelling region with moderate to high paleoproductivity and paleo c org fluxes and low seasonality as indicated by the bulimina mexicana gavelinopsis translucens assemblage and low mean 13 c h elegans 3 the cape yubi filament region with moderate to high paleoproductivity high paleo c org fluxes and high seasonality as indicated by the cassidulina laevigata nonionella iridea assemblage and 13 c h elegans as low as those from the cape ghir upwelling region 4 the cape ghir filament region with highest paleoproductivity high paleo c org fluxes and seasonality as indicated by the epistominella exigua assemblage and highest 13 c h elegans productivities during the lgm and today were compared based on faunal assemblages and 13 c values 13 c 13 c lgm 13 c present of three infaunal species generally during the lgm the upwelling region was characterized by higher paleo c org fluxes particularly in the area between the capes similar seasonality along the coast and higher seasonality further offshore than at present day for the reconstruction of lgm water mass stratification we used the 13 c of cibicidoides wuellerstorfi and equilibrium adjusted 18 o of several species deep water mass stratification is characterized by glacial north atlantic central water above 800 m by glacial mediterranean outflow water between 800 and 1900 m and glacial north atlantic deep water below 1900 m and a southern source deep water mass this means considering the lowered glacial sea level water mass stratification during the lgm was similar to present day conditions

trace element geochemistry of altered volcanic ash layers tonsteins in late permian coal bearing formations of eastern yunnan and western guizhou provinces china trace element compositions were determined by instrumental neutron activation analysis inaa in 30 samples of synsedimentary volcanic ash derived tonsteins and detrital claystones from coal seams within the late permian coal bearing formation of eastern yunnan and western guizhou provinces china the characteristics of trace element geochemistry in the tonsteins can be distinguished from those of detrital claystones because of the former s unique volcanic ash origin the detrital claystones are characterized by their relatively high content of v ti sc cr co and ni relatively low content of th and u th u ratio and small negative eu anomaly eu eu 0 63 0 93 overall these trace element characteristics are consistent with a mafic source similar to the composition of basalt rocks in the erosional region on the western edge of the study area in contrast the tonsteins are low in v ti sc cr co and ni contents and have a high th u ratio with a distinct negative eu anomaly eu eu normally in the range of 0 2 0 4 consistent with a silicic magmatic source within the group of tonsteins those from the lower section p2 1 of the coal bearing formation are relatively high in ti zr hf nb ta and rare earth elements ree as compared to those from the middle and upper sections p2 2 3 in trace element discrimination diagrams scatter plots of hf ta ti ta ti v hf sc lu hf and lu th tonsteins from the p2 1 horizon always fall in isolated distribution areas separate from the tonsteins of the p2 2 3 horizon these results suggest that the source materials of tonsteins from the two separate horizons were probably derived from volcanic ash falls of two distinctly different natures based on a comparison of the concentrations and assemblages of trace elements between various magmatic rocks the source materials of tonsteins from p2 1 horizon were mostly composed of calc alkalic silica poor volcanic ash similar to rhyodacitic magma whereas those from p2 2 3 were apparently more siliceous and k rich rhyolitic magma thus tonsteins from the two different horizons are characterized by unique geochemical properties which remain constant over a wide lateral extent integration of trace elemental compositions with mineralogical and textural observations makes possible the establishment of tonstein stratigraphy thus facilitating more precise and reliable coal seam correlations

geological controls on the mineralogy and geochemistry of the beypazari lignite central anatolia turkey abstract the raw coal from the cayirhan mine beypazari basin turkey contains an average of 28 5 mineral matter consisting up to 80 zeolites the coal seam is split by a 1 m thick tuffaceous siltstone into the upper first tv and lower second tb seams which contain essentially different zeolites the first seam contains ca rich zeolites clinoptilolite heulandite whilst the second seam contains na rich zeolites analcime experimental work has shown that a na rich activation solution will produce na rich zeolites when the original volcanic glass is na rich but will produce ca rich zeolites when the volcanic material is ca rich it is thought that a na rich activation solution derived from contemporaneous volcanics in the beypazari basin reacted with volcanic tuffs of different chemical composition to produce the vertical variability in the mineral matter of the two seams trace element analyses of the raw coal showed that they are enriched in as b cr ni and zr when compared to world wide averages of coal they are also enriched in the major elements na and k these elements are probably also derived from a volcanic source barium and sr show a clear affinity for analcime whilst li cr ni cu zn co and ga show a clear affinity for clinoptilolite heulandite trace elements showing a positive correlation with the organic matter are mn b be ge y zr nb hf w and u manganese u th sc ge and hree heavy rare earth elements show correlations with phosphate trace elements showing correlation with both fe and s contents are co mo ta pb and iree intermediate rare earth elements arsenic and v seem to have mixed affinities with sulphides and zeolites and organic matter and zeolites respectively although a proportion of the as b and s are retained in the ash during coal combustion due to the sorption mechanism of cao derived from the clinoptilolite heulandite decomposition significant emissions of these elements may arise from the cayirhan thermal power station due to the anomalously high concentrations of these elements in the beypazari coal the high total alkali metal content of these coals exceeds the recommended maximum for steam coal but it is believed that sodium occurring in a mineralogical form such as analcime is not as likely to contribute to boiler fouling as organically associated sodium

mid holocene regional reorganization of climate variability analyses of proxy data in the frequency domain abstract recurrent shifts in holocene climate define the range of natural variability to which the signatures of human interference with the earth system should be compared characterization of holocene climate variability at the global scale becomes increasingly accessible due to a growing amount of paleoclimate records for the last 9000 11 000 yr here we integrate 124 proxy time series of different types e g 18o lithic composition and apply a modified lomb scargle spectral analysis after bootstrapping the data in moving time windows we observe an increased probability for generation or loss of periodic modes at the mid holocene spatial autocorrelation of spectral changes robustly reveals that this in activation of modes was organized in regional clusters of sub continental size within these clusters changes in spectral properties are unexpectedly homogeneous despite different underlying climatological variables oscillations in the climate system were amplified especially at the upwelling areas and dampened in the north atlantic we cross checked the spectral analysis by counting events in the time series and tested against possible dating errors in individual records or against an overestimation of singular events a combination of different mechanisms may have affected the coupling intensity between climate subsystems turning these more or less prone to oscillations

productivity response in the north canary basin to climate changes during the last 250 000 yr a multi proxy approach we present results from the investigation of the primary productivity record over the last 250 kyr in the north canary basin 30 n off northwest africa two distinct productive systems interfere in this area the oligotrophic open ocean and the upwelling filament off cape ghir that occasionally carries offshore cool nutrient rich waters the following geochemical and micropaleontological paleoproductivity proxies have been used in our study calcium carbonate barium excess baexcess total organic carbon toc and diatoms time series analysis of these proxies indicates that paleoproductivity in the north canary basin underwent important changes following precession and eccentricity cycles while the precessional signal appears to be mainly related to trade wind strength superimposed peaks in baexcess toc and diatom records point to large productivity events at terminations i ii and iii lowering of the north atlantic sea surface temperatures by melt water discharges which in turn strengthened the azores high pressure center and increased trade wind velocities is postulated as the mechanism to explain the enhancement of the coastal upwelling and associated filaments at terminations additionally the canary current may play a role in transmitting cold melt waters and nutrients from higher latitudes to the north canary basin

the effects of volcanic ash on the maceral and chemical composition of the c coal bed emery coal field utah abstract volcanic ash which fell in the peat swamp that formed the upper cretaceous c coal bed ferron sandstone member of the mancos shale utah produced semi impermeable layers that caused the ponding of surface waters coal samples from directly above tonsteins altered volcanic ash partings are enriched in desmocollinite telinite and detrocollinite as a result of poorly drained swamp conditions coal samples from directly below tonsteins are enriched in semifusinite inertodetrinite and fusinite as a result of well drained conditions leaching of the volcanic ash or the incorporation of volcanic ash in peat provided a source for many elements including zr nb th and ce that are enriched in coal samples taken from directly above and below tonsteins

quick clay a case study of chemical perspective in southwest sweden quick clay a soil that changes from normal firm ground to a liquid mass when it is disturbed has been involved in most of the large and serious clay slides in sweden norway and canada the location time of occurrence and size of quick clay slides are difficult to predict and large slides may cause great devastation some geochemical studies of swedish quick clay were done in the 1960s and early 1970s but no systematic studies of the interrelationships of pore water chemistry mineralogy geotechnical properties and other parameters on quick clays in sweden have been published such studies are of national and general interest because of the many combinations of rock flour source areas and sedimentation conditions that occurred across central sweden and into the baltic sea area during deglaciation in this study geotechnical properties related to the in situ chemistry at one quick clay site were extensively studied and spot sampling was conducted at two other locations in southwest sweden in this area the clay minerals mainly are non expanding phyllosilicate minerals illite and primary minerals quartz feldspar which is consistent with previous studies of quick clay mineralogy extensive leaching has occurred at all three locations at the extensively studied site surte the lowest salinity was found at the greatest depth inferring that the leaching by fresh water was accomplished by water movement upward and laterally through the sediment from the underlying bedrock this is consistent with the local setting where bedrock hills rise sharply to over 100 m above the marine sediment surface an artesian pressure would also be anticipated at this location there is a correlation negative between sensitivity and salinity but there is an indication that the maximum salinity or electrical conductivity consistent with the quick clay behaviour is higher than reported elsewhere however for high sensitivities the salinity is about the same as reported elsewhere in the deepest part of the borehole there is a higher content of fe and al in the pore water indicating reduced state further work is needed to confirm the difference in salinity and to investigate the possible interplay of salinity and potential dispersing agents such as the role of anoxic conditions in this region further work is especially needed in the locations where the sediment accumulation occurred under lower salinity conditions at all three locations high remoulded shear strength and low sensitivity have been seen near the surface together with a decrease in pore water cation concentrations

soil moisture fluctuations recorded in saharan dust deposits on lanzarote canary islands over the last 180 ka abstract aeolian sediments trapped in volcanically dammed valleys on lanzarote canary islands were investigated in order to reveal environmental changes over the last 180 ka clay content and frequency dependent magnetic susceptibility were used as proxies for pedogenesis and palaeo soil moisture during the last 180 ka these proxies showed a general pattern of enhanced soil moisture during glacials and stadials and more arid conditions during interglacials and interstadials comparisons of these results with proxies from regional palaeoclimate studies identified a positive correlation with proxies of trade wind strength off northwest africa and inverse correlations with both sea surface temperatures in the northeast atlantic and the extent of mediterranean vegetation possible causes for the observed pattern include a glacial enhancement of precipitation from westerly cyclones a change in relative humidity due to fluctuating air temperatures and an occasional influence of the african summer monsoon although it is not yet possible to clearly differentiate among these factors it is clear that the first two factors must have been primarily dominant these results represent the first quasi continuous terrestrial data testifying to environmental changes in the northwest african coastal area for the last 180 ka and complement the abundant data derived from marine cores of the region high latitude dynamics had a major influence in this area and were intermediated by north atlantic sea surface temperatures a possible negative correlation can also be observed with the orbital obliquity cycle with a 10 ka time lag which is similar to the lag recorded from north atlantic sea surface temperatures

geochemistry of trace elements in coals from the zhuji mine huainan coalfield anhui china the abundances of nine major elements and thirty eight trace elements in 520 samples of low sulfur coals from the zhuji mine huainan coalfield anhui china were determined samples were mainly collected from 10 minable coal seams of 29 boreholes during exploration the b content in coals shows that the influence of brackish water decreased toward the top of coal seams marine transgression and regression occurred frequently in the lower shihezi formation a wide range of elemental abundances is found weighted means of na k fe p be b co ni cr se sb ba and bi abundances in zhuji coals are higher and the remainder elements are either lower or equal to the average values of elements in coals of northern china compared to the chinese coals the zhuji coals are higher in na k be b cr co se sn sb and bi but lower in ti p li v and zn the zhuji coals are lower only in s p v and zn than average u s and world coals potassium mg ca mn sr as se sb and light rare earth elements lree had a tendency to be enriched in thicker coal seams whereas fe ti p v co ni y mo pb and heavy rare earth elements hree were inclined to concentrate in thinner coal seams the enrichment of some elements in the shanxi or upper shihezi formations is related to their depositional environments the elements are classified into three groups based on their stratigraphic distributions from coal seams 3 to 11 2 and the characteristics of each group are discussed lateral distributions of selected elements are also investigated the correlation coefficients of elemental abundances with ash content show that the elements may be classified into four groups related to modes of occurrence of these elements

glacial interglacial modulation of the marine nitrogen cycle by high latitude o2 supply to the global thermocline 1 an analysis of sedimentary nitrogen isotope records compiled from widely distributed marine environments emphasizes the global synchrony of denitrification changes and provides evidence for a strong temporal coupling of these variations to changes in nitrogen fixation as previously inferred we explain the global coherence of these records by a simple physical control on the flux of dissolved oxygen to suboxic zones and the coupling to fixation via the supply of phosphorus to diazotrophs in suitable environments according to our hypothesis lower glacial stage sea surface temperature increased oxygen solubility while stronger winds in high latitude regions enhanced the rate of thermocline ventilation the resultant colder rapidly flushed thermocline lessened the spatial extent of denitrification and consequently n fixation during warm periods sluggish circulation of warmer less oxygen rich thermocline waters caused expansion of denitrification zones and a concomitant increase in n fixation local fluctuations in export productivity would have modulated this global signal

the influence of organic matter diagenesis on caco3 dissolution at the deep sea floor abstract in situ benthic flux chamber measurements were performed at seafloor locations in the atlantic and pacific oceans where the bottomwaters were supersaturated approximately saturated and undersaturated with respect to calcite there was no evidence of significant dissolution at or above the saturation horizon below the saturation horizon however significant benthic fluxes of titration alkalinity and calcium out of the sediments were observed indicating appreciable dissolution where observed the rate of dissolution is consistent with a rate expression of reaction order 4 5 and a rate constant in the range of 0 05 to 0 5 per day a numerical simulation was constructed to represent organic matter and caco3 diagenesis at the seafloor at the supersaturated and near saturation sites the model over predicts the influence of metabolically produced co2 on the extent of caco3 dissolution it is possible that these results can be reconciled by a better understanding and parameterization of organic matter mineralization and porewater transport processes in surface sediments the primary factors to be considered include 1 the oxidation state of the carbon being oxidized 2 the vertical distribution of oxidation rates including the role of doc in sediment remineralization 3 the influence of nondiffusive transport of near surface porewaters and 4 the influence of episodic depositional events on organic and inorganic carbon cycling

geochemistry of the late permian no 30 coal seam zhijin coalfield of southwest china influence of a siliceous low temperature hydrothermal fluid this paper describes the influence of siliceous low temperature hydrothermal fluid on the elemental concentrations and mineralogical characteristics of the late permian anthracitic ro max 3 58 coal seam no 30 from the zhijin coalfield in western guizhou province sw china coal samples were examined using instrumental neutron activation analysis inductively coupled plasma mass spectroscopy inductively coupled plasma atomic emission spectrometry x ray fluorescence powder x ray diffraction scanning electron microscopy equipped with energy dispersive x ray and isotope analysis the modes of occurrence of elements were determined using a sequential chemical extraction procedure the studies indicate that the no 30 coal seam has a very high content of veined quartz vol 9 4 whose isotope values of 30si and 18o are 0 6 and 15 4 respectively indicating that the quartz originated from siliceous low temperature hydrothermal fluid formation temperature 160 220 c rather than detrital material of terrigenous origin or magmatic hydrothermal inputs results of scanning electron microscopy equipped with energy dispersive x ray and sequential chemical extraction procedure show that the veined quartz is the dominant source of fe cu u pd pt and ir which are as high as 2 31 356 8 2 1 2 43 and 0 006 g g in this coal seam respectively the studies have also found that elements such as fe and cu are mainly in the veined quartz and they do not occur as sulfides in this coal seam in sharp contrast to many other coal seams in china the geochemical and mineralogical anomalies of the coal are attributed to the siliceous low temperature hydrothermal fluid

testing models of past ocean chemistry using foraminifera 15n 14n previous models have attempted to explain glacial to interglacial changes in atmospheric pco2 by invoking changes in the ocean s nutrient concentration or regional changes in nutrient utilization nitrogen is limiting to primary production and has a residence time in the ocean compatible with glacial to interglacial variations but up to now there has been no geological indicator for glacial to interglacial changes in the ocean s nitrogen cycle we propose that 15n 14n ratios for the organic matrix of preserved foraminifera yield an interpretable 15n record we have developed models to study the relationship between plausible changes in the ocean s nitrogen cycle and resulting changes in the 15n 14n ratio of dissolved no3 our model results demonstrate that 15n 14n ratios exhibit excursions during periods in which the oceans are accumulating or losing nitrogen regardless of the means by which these changes occur foraminifera 15n 14n results for a pacific and an atlantic core provide evidence against wide spread glacial anoxia a consequence of many models of ocean chemistry we suggest that increasing shelf sediment denitrification upon deglaciation reduced nitrogen concentrations in the modern ocean ambiguities between the two foraminifera 15n 14n records indicate that local effects associated with changes in hydrography or ecology need to be studied further

mineralogical and compositional characteristics of late permian coals from an area of high lung cancer rate in xuan wei yunnan china occurrence and origin of quartz and chamosite abstract some townships in xuan wei county yunnan province have one of the highest lung cancer mortality rates in china and the epidemic disease in the area has generally been attributed to the polycyclic aromatic hydrocarbons pahs released from domestic coal burning however the cancer causing culprit is not settled as tian tian l 2005 coal combustion emissions and lung cancer in xuan wei china ph d thesis university of california berkeley found nanometer quartz in these coals soot emissions and lung cancer tissues we have conducted mineralogical and geochemical studies of the coals from xuan wei for the purpose of shedding light on the minerals which may be related to the epidemic lung cancer in this paper abundances modes of occurrence and origins of minerals and elements in the coals from two mines in xuan wei have been studied using optical microscope low temperature ashing x ray diffraction analysis scanning electron microscope equipped with energy dispersive x ray spectrometer and inductively coupled plasma mass spectrometry the minerals in the coals are mainly composed of quartz chamosite kaolinite and calcite the particle size of quartz is rather small mostly less than 20 m and it is of authigenic origin chamosite occurs mainly as cell fillings the occurrence of quartz and chamosite indicates that they were derived from the hydrothermal fluids epigenetic calcite is derived from calcic fluids kaolinite is derived mainly from sediment source region of kangdian oldland to the west of coal basin the composition of xuan wei coal is high in sio2 fe2o3 tio2 cao mno v co ni cu and zn the high sio2 content is attributed to quartz and the fe2o3 content to chamosite the high mn and low mg contents in the coal indicate the inputs of hydrothermal fluids cao occurs mainly in epigenetic calcite elements ti co ni cu zn and rare earth elements were derived from the basaltic rocks at sediment source region

geologic control on soil composition and properties lake ojibway clay plain matagami quebec varved clays deposited in proglacial lake ojibway at matagami quebec were derived from two source areas carbonate deficient precambrian crystalline igneous rocks from new quebec to the east and

surface ocean density gradients during the last glacial maximum we have compiled published planktonic foraminiferal oxygen isotope values from the tropical to subtropical atlantic and pacific for the late holocene and last glacial maximum lgm we interpret the spatial distribution of 18o values in terms of meridional density gradients in the lgm surface ocean and discuss implications on tropical ocean thermocline structure in both oceans glacial 18o values display a pattern of interhemispheric asymmetry evidenced by increasingly higher glacial 18o values toward northern latitudes the 18o derived density estimates suggest that the northern subtropical surface ocean density was higher during the lgm than today which has significant implications on lgm thermocline ventilation in the atlantic steeper density gradients in the northern subtropics during the lgm are consistent with a more compressed subtropical gyre and thermocline water formation farther south than today in the pacific the steeper density gradients suggest a significant reduction in freshwater fluxes to the northern tropical and subtropical regions which raises the possibility of a more significant component of northern hemisphere source waters to the tropical pacific thermocline these predictions could be tested with numerical ocean models that assess the structure of the tropical thermocline in the glacial ocean

upwelling intensity and filament activity off morocco during the last 250 000 years abstract the high productive upwelling area off morocco is part of one of the four major trade wind driven continental margin upwelling zones in the world oceans while coastal upwelling occurs mostly on the shelf biogenic particles derived from upwelling are deposited mostly at the upper continental slope nutrient rich coastal water is transported within the cape ghir filament region at 30 n up to several hundreds of kilometers offshore both upwelling intensity and filament activity are dependent on the strength of the summer trades this study is aimed to reconstruct changes in trade wind intensity over the last 250 000 years by the analysis of the productivity signal contained in the sedimentary biogenic particles of the continental slope and beneath the cape ghir filament detailed geochemical and geophysical analyses toc carbonate c n 13corg 15n 13c of benthic foraminifera 18o of benthic and planktic foraminifera magnetic susceptibility have been carried out at two sites on the upper continental slope and one site located further offshore influenced by the cape ghir filament a second offshore site south of the filament was analyzed toc magnetic susceptibility to distinguish the productivity signal related to the filament signal from the general offshore variability higher productivity during glacial times was observed at all four sites however the variability of productivity during glacial times was remarkably different at the filament influenced site compared to the upwelling influenced continental slope sites in addition to climate related changes in upwelling intensity zonal shifts of the upwelling area due to sea level changes have impacted the sedimentary productivity record especially at the continental slope sites by comparison with other proxies related to the strength and direction of the prevailing winds si al ratio as grain size indicator pollen the productivity record at the filament influenced site reflects mainly changes in trade wind intensity our reconstruction reveals that especially during glacial times trade wind intensity was increased and showed a strong variability with frequencies related to precession

contrasting paleoceanographic conditions off morocco during heinrich events 1 and 2 and the last glacial maximum abstract past hydrological and primary productivity regimes on the basis of dinocyst and foraminiferal fossil assemblages as well as on stable isotopes o c and alkenones were investigated over the last 30 ka at upwelling site md04 2805 cq off morocco the results show highest upwelling intensity during heinrich event he 1 time coeval with a distinct plateau of heavy planktonic 13 c values high concentrations of pinus pollen and heterotrophic dinocysts caused by an increased northern wind regime in addition we also present regional reconstructions of paleo sea surface temperatures ssts using three different proxy tools dinocyst and foraminiferal transfer functions as well as alkenones u k 37 sst the reconstructed ssts depict coherent scenarios as modulated by the typical northern hemisphere climatic fluctuations furthermore specific occurrences of the dinocyst spiniferites lazus and of the foraminifer turborotalita quinqueloba are noted for he 2 he 1 and the younger dryas whereas in the alboran sea and in peri iberian waters these cold events were accompanied by the dinocyst bitectatodinium tepikiense and the subpolar foraminifer neogloboquadrina pachyderma s both implying a marked southward shift in the planktonic population in response to the migration of polar water masses this very pronounced demarcation between the planktonic communities better seems to attest the presence of a distinct hydrological structure in proximity of the strait of gibraltar which separated at that time african north of morocco from european southern iberia water masses

minerals and potentially hazardous trace elements in the late triassic coals from the qiangtang basin china abstract the tumen coal mine has the largest coal resources in tibet which have been developed and utilized as an important energy source in the last decades it has raised some health problems during the coal exploration and utilization in tibet fifty late triassic coal or coaly samples were picked up from the qiangtang basin tumen mine woruoshan and hongshuihe areas to determine the minerals potentially hazardous elements and their mode of occurrence and possible sources coal samples from the qiangtang basin have medium and high ash yields 15 20 47 88 with low or medium high total sulfur content 0 04 4 86 minerals in qiangtang basin coal include clay minerals dolomite quartz pyrite siderite and hematite and trace amounts of halite feldspar anhydrite barite chromite and galena potentially hazardous trace elements in coal samples include as hg pb and se arsenic is controlled mainly by aluminosilicate minerals mercury occurs mainly as an organic bound form the organically bound pb is dominant selenium is controlled mainly by fe bearing probably pyrite a proportion of the elevated concentrations of as hg pb and se in qiangtang basin coal may be related to underlying shale bed these elements might have been eroded or leached from the shale bed which were subsequently transported and accumulated syngenetically in the coal forming peat swamps the enrichment of as hg pb and se in qiangtang basin coal however is also partly to be related to magmatic hydrothermal fluids

changes in east atlantic deepwater circulation over the last 30 000 years eight time slice reconstructions using 95 epibenthic 13c records eight time slices were reconstructed to trace the distribution of east atlantic deepwater and intermediate water masses over the last 30 000 years our results show that there have been three distinct modes of deepwater circulation near the stage 3 2 boundary the origin of north atlantic deep water nadw was similar to today mode 1 however after late stage 3 the source region of the nadw end member shifted from the norwegian greenland sea to areas south of iceland mode 2 a reduced nadw flow persisted during the last glacial maximum with constant preformed 13c values the nutrient content of nadw increased markedly near the azores fracture zone from north to south probably because of the mixing of upwelled antarctic bottom water aabw from below which then advected with much higher flux rates into the northeast atlantic later the spread of glacial meltwater over the north atlantic led to a marked short term ventilation minimum below 1800 m about 13 500 14c years ago mode 3 the formation of nadw recommenced abruptly north of iceland 12 800 12 500 years ago and reached a volume approaching that of the holocene in the younger dryas 10 800 10 350 years b p another short term shutdown of deepwater formation followed between 10 200 and 9 600 years b p linked to a further major meltwater pulse into the atlantic each renewal of deepwater formation led to a marked release of fossil co2 from the ocean the likely cause of the contemporaneous 14c plateaus over the last 9000 years deepwater circulation varied little from today apart from a slight increase in aabw about 7000 14c years ago it is also shown that the oxygenated mediterranean outflow varied largely independent of the variations in deepwater circulation over the last 30 000 years

minerals and potentially hazardous trace elements in marine oil shale new insights from the shengli river north surface mine northern tibet china the shengli river changshe mountain oil shale zone including the changliang mountain shengli river oil shale the shengli river north oil shale and the changshe mountain oil shale represents potentially the largest marine oil shale resource in china new geochemical data from the shengli river north oil shale are presented to evaluate potentially hazardous trace elements in oil shale and to discuss possible factors controlling the geochemical anomalies oil shale samples from the shengli river north area are characterized by high ash yield 59 25 66 27 and toc content 4 77 9 35 with low total sulfur content 0 1 1 56 and intermediate shale oil content 3 60 16 30 minerals in the shengli river north oil shale include calcite clay minerals quartz dolomite and fe bearing minerals e g pyrite limonite and hematite and trace amounts of zeolite apatite and barite potentially hazardous trace elements in oil shale samples include as se mo f ni cd and hg arsenic is present probably in both organic and inorganic matter selenium is controlled mainly by fe bearing probably pyrite while f and cd occur mainly as apatite the organically bound mo and ni are dominant and hg probably occurs as a substitution in the structure of pyrite apatite and calcite the elevated concentrations of f and cd in the shengli river north oil shale may be related to sediment source water chemistry may have played an important role for ni and mo enrichments while the enrichment of se in the oil shale samples is possibly related to hydrothermal fluids other elements including hg and as are probably related to several factors

records of terrestrial sulfur deposition from the latest permian coals in sw china abstract different sulfur fractions of low sulfur average 0 11 coals from the latest permian in southwestern china were analyzed isotopically at a high vertical resolution to examine the ramifications for potential terrestrial extinction mechanisms at the permo triassic boundary s org organic sulfur accounts for 87 of the total sulfur content on average while s py pyritic sulfur is very low 13 of the total sulfur content and ca 0 01 of the whole sample weight and relatively constant throughout the profile except for some insignificant additions in clay rich layers these indicate the possible differential contribution of local diagenesis during the early stages of peat accumulation the 34 s org values have a relatively narrow range from 1 5 to 7 6 while the 34 s py values have a wider range from 0 8 to 34 1 suggesting that pyrite was possibly formed in different stages and that there was negligible bacterial contribution to the primary organic sulfur fraction thus the organic sulfur signal in the coal is largely sourced from the original plant material and records temporal variations in the isotopic composition of the sulfur input to the coal forming environment the stratigraphically lower coal b3 has 34 s org values around 4 while the stratigraphically higher coal b2 which is closer to the permian triassic boundary has clearly higher 34 s org values ranging from 5 3 to 7 6 this change is most likely due to increased marine sulfate aerosol inputs into the coal forming peatland caused by coastline retreat during late permian transgression importantly there is no evidence in these discrete intervals of coal formation to indicate a dominant role of atmospheric inputs of isotopically lighter sulfur from either h 2 s released from euxinic oceans or volcanic so 2 this militates against theories that implicate such sources of sulfur in terrestrial extinction mechanisms at the end permian

concentration and distribution of elements in late permian coals from western guizhou province china abstract with the aim of better understanding geochemistry of coal 71 late permian whole seam coal channel samples from western guizhou province southwest china were studied and 57 elements in them were determined the contents of al ca co cr cu fe ga hf k li mn mo nb ni sn ta ti th u v zr and rees in the late permian coals from western guizhou province are higher than the arithmetic means for the corresponding elements in the us coals whereas as ba br f hg p se and tl are lower compared to common chinese coals the contents of co cr cu ga hf li mn mo ni sc sn ti u v zn and zr in western guizhou coals are higher and as f hg rb sb tl and w are lower five groups of elements may be classified according to their mode of occurrence in coal the first two group a tm yb lu y er ho dy tb ce la nd pr gd sm and group b as sr k rb ba f ash si sn ga hf al ta zr be th na have high positive correlation coefficients with ash yield and they show mainly inorganic affinity some elements from group b such as ba be ga hf and th are also characterized by significant aluminosilicate affinity in addition arsenic also exhibits high sulfide affinity r s fe 0 5 the elements which have negative or lower positive correlation coefficients with ash yield with exceptions of bi cs nb mn se and ti are grouped in other four associations group c cr v mo u cd tl group d hg li sc ti eu nb cs w group e bi sb and group f co ni cu pb zn mg se ca mn s fe the correlation coefficients of some elements including co cr cu fe hg li mo ni p s sc u v and zn with ash yield are below the statistically significant value only cr and cu are negatively correlated to ash yield 0 07 and 0 01 respectively showing intermediate organic and inorganic affinity manganese and fe are characterized by carbonate affinity probably due to high content of epigenetic veined ankerite in some coals phosphorus has low correlation coefficients with any other elements and is not included in these six associations there are five possible genetic types of enrichment of elements in coal from western guizhou province source rock volcanic ash low temperature hydrothermal fluid groundwater and magmatic hydrothermal inputs

a 300 kyr high resolution aridity record of the north african continent new oxygen isotope data and a high resolution carbonate record of a core from the northwest african margin are presented in combination with geochemical zr rb ratio al ba organic carbon and biogenic opal fluxes and sedimentological median grain size parameters to show variations in african continental aridity wind strength and upwelling productivity the carbonate record is diluted by the supply of aeolian dust from the arid saharan region of north africa and is seen to vary with a characteristic sawtooth pattern indicating rapid increases in dust flux followed by gradual declines spectral analysis of the carbonate profile and comparison with specmap stacked oxygen isotope and etp solar radiation profiles shows that the precessional 23 kyr insolation induced african climate system is decoupled from global ice volume climate changes operating on a 100 kyr frequency detailed studies of glacial terminations i ii and iii confirm the presence of rapid short timescale climatic variations in aridity

geochemical and mineralogical characteristics of a power station feed coal eggborough england abstract chemical and mineralogical analyses are presented for a power station feed coal in the yorkshire coalfield u k the mineralogy of the whole coal consists of quartz kaolinite illite mixed layer clay chlorite pyrite and carbonates pyrite carbonates and some of the kaolinite are diagenetic in separated low density fractions of the coal both pyrite and kaolinite are concentrated relative to the detrital minerals compared with the high density fractions the detrital clay mineralogy of these low density fractions contains less chlorite and the mixed layer clay to illite ratio is higher which is consistent with a grain size control during sedimentation the major element analyses are comparable with mudrocks in the stratigraphic sequence but there is evidence of na 2 o enrichment related to connate brinnes and the fe 2 o 3 content shows significant enrichment particularly in the ashes of the low density fractions the dissolution of oxhydroxide grain coatings associated with detrital sediment in the coal and also in the adjacent strata are probable sources of the iron in the diagenetic pyrite there is evidence of iron mobility in the sedimentary sequence and introduction into the coal itself during diagenesis within the coal trace elements are also enriched on an ash basis relative to the mudrocks and their origin is also probably very similar to that of iron a noteworthy feature of the trace element enrichment is that the enrichment factors for a number of elements are comparable with those determined for marine black shales in the sequence this suggests a common origin for the elements during the diagenetic processes analysis of the coal density fractions after correcting for detrital mineralogy suggests pb cu ni zn and possibly mn are associated with pyrite and v sr ba zr and nb are either directly or indirectly associated with organic components possibly zr and nb originate from dispersed volcanic ash

sedimentary nitrogen isotopic ratio as a recorder for surface ocean nitrate utilization in two contrasting regions of the ocean the equatorial pacific and the southern ocean the 15n of core top sediments were strongly related to no3 in surface waters with distance from the equator in the equatorial pacific 15n increased from 7 to 16 as no3 decreased from 8 m to 0 1 m going from 60 to 30 s in the se indian ocean core top 15n increased from 5 to 11 as surface no3 decreased from 25 m to 0 1 m these results are strong evidence that sedimentary 15n in these regions is recording the increasing isotopic enrichment of near surface no3 with its depletion by phytoplankton in the case of the equatorial pacific 15n values for sinking particles collected at 150 m matched well the core top sediment values demonstrating little diagenetic alteration of the near surface generated isotopic signal these equatorial pacific data sets have variations with near surface no3 consistent with rayleigh fractionation kinetics for a fractionation factor u of 2 5 this value is substantially lower than previously found for temperate or polar regions perhaps as a result of differences in phytoplankton species assemblage or growth condition in the southern ocean south of the polar front comparison of 15n values for opal rich sediments south and sinking particles indicates an apparent 5 diagenetic enrichment relative to the surface generated signal that requires further investigation this exception aside our observations show that the surface water relationship of increasing 15n with increasing no3 depletion is generally transmitted to and preserved in the sediments an important requirement for further development and application of this important paleoceanographic tool

orbital forcing of dust supply to the north canary basin over the last 250kyr abstract the canary basin lies in a region of strong interaction between the atmospheric and ocean circulation systems trade winds drive seasonal coastal upwelling and dust storm outbreaks from the neighbouring sahara desert are the major source of terrigenous sediment to investigate the forcing mechanisms for dust input and wind strength in the north canary basin the temporal pattern of variability of sedimentological and geochemical proxy records has been analysed in two sediment cores between latitudes 30 30 n and 31 40 n spectral analysis of the dust proxy records indicates that insolation changes related to eccentricity and precession are the main periods of temporal variation in the record si al and grain size of the terrigenous fraction show an increase in glacial interglacial transitions while al concentration and fe al ratio are both in phase with minima in the precessional index hence the results obtained show that the wind strength was intensified at terminations at times of maxima of northern hemisphere seasonal insolation when the african monsoon was enhanced the north canary basin also received higher dust input this result suggests that the moisture brought by the monsoon may have increased the availability of dust in the source region

last interglacial sea surface warming during the sea level highstand in the canary islands implications for the canary current and the upwelling off african coast abstract the canary islands east of the north atlantic ocean 27 n 29 n are under the influence of the canary current the descending branch of the north atlantic gyre which is modulated by coastal upwelling off north west africa they constitute strategic sites for palaeoclimatic reconstructions especially for the last interglacial lig 129 to 116 ky bp estimated to be warmer than present seventy four carbon and oxygen isotope bulk analyses and time series measurements were performed on 32 aragonitic mollusc shells from the lig marine deposits on lanzarote and fuerteventura islands during a period of sea level highstand that we estimated to occur between 125 and 119 116 ky bp our sst calculations inferred from shell 18o values using available isotopic fractionation equations provide a seasonal sst amplitude ranging from 3 5 c to 6 0 c in agreement with the modern seasonal amplitude along with a mean sst comprised between 20 4 1 3 c and 22 2 1 2 c with respect to the pre industrial times we deduce a positive sst anomaly in the range of 1 0 1 4 c to 2 8 1 3 c consistent with the presence of the species persististrombus latus typical of warm ssts although this finding does not match with the zonal negative anomaly of a reconstructed sst at low latitudes of the north atlantic it is nevertheless corroborated by other climate reconstructions in the northeastern tropical atlantic region we attribute this trend to an excess of summer insolation during the lig which warmed the canary current enhanced by a weakening of the north african upwelling the entire north atlantic gyre was probably warmer during the lig

deep dwelling foraminifera as thermocline temperature recorders we measured the oxygen isotopic composition of the deep dwelling foraminiferal species g inflata g truncatulinoides dextral and sinistral and p obliquiloculata in 29 modern core tops raised from the north atlantic ocean we compared calculated isotopic temperatures with atlas temperatures and defined ecological models for each species g inflata and g truncatulinoides live preferentially at the base of the seasonal thermocline under temperature stress i e when the base of the seasonal thermocline is warmer than 16 c g inflata and g truncatulinoides live deeper in the main thermocline p obliquiloculata inhabits the seasonal thermocline in warm regions we tested our model using 10 cores along the mauritanian upwelling and show that the comparison of o variations registered by the surficial species g ruber and g bulloides and the deep dwelling species g inflata evidences significant glacial interglacial shifts of the mauritanian upwelling cells

rare earth minerals in a no tonstein section of the dean fire clay coal knox county kentucky abstract the dean fire clay coal in knox county kentucky does not contain the megascopically visible ash fall tonstein present in most other sections of the coal bed like the fire clay tonstein a low ash portion of the coal is enriched in rare earth elements 2400 ppm on ash basis in addition to kaolinite produced in the diagenesis of volcanic glass transmission electron microscopy studies indicate the coal contains primary kaolinite la ce nd th monazite barium niobate native gold and fe ni cr spinels the mineral assemblages particularly the kaolinite monazite association and its similarity to the tonsteins in coal to the east demonstrate the coal was subject to the ree enriched volcanic ash fall apparently just at a more dilute level than at locations where the tonstein is present

siliceous sedimentary record of the last 280 kyr in the canary basin nw africa abstract siliceous microfossils were quantified in four sedimentary sequences off northwest africa in order to disclose the productivity story of the last 280 kyr three sediment cores retrieved along an e w profile at about 29 n geob4240 geob4241 and geob4242 and one core geob4216 from the highly productive area off cape ghir in the canary island region at 29 n along all but the most offshore sequences geob4242 coincidence of high diatom accumulation rates dar and high abundances of chaetoceros spores the upwelling related species indicate glacial stages isotope stages is 4 and 2 as more productive than the interglacial intervals is5 and holocene the dar in the coastal area of the canary basin during is2 is of the same order of magnitude 10 8 valves cm 2 kyr 1 reported for cape blanc and one order of magnitude higher than reported for the iberian margin the deviation observed between the offshore higher dar at is3 and 6 and the coastal diatom records higher dar at is2 and 4 may be a reflection of local productivity generated by wind input of nutrients and advection from coastal sources the occurrence of dar spikes at the timing of some heinrich events seems to support the hypothesis of productivity maxima associated with the presence of meltwater off nw africa as previously proposed by other authors

characteristics of zircons from volcanic ash derived tonsteins in late permian coal fields of eastern yunnan china abstract kaolinitic tonsteins of altered synsedimentary volcanic ash fall origin are well developed in the late permian coal bearing formations of eastern yunnan province because of their unique origin wide lateral extent relatively constant thickness and sharp contacts with enclosing strata great importance has been attached to these isochronous petrographic markers in order to compare tonsteins with co existing non cineritic claystones and characterize the individuality of tonsteins from different horizons for coal bed correlation a semi quantitative method was developed that is based on statistical analyses of the concentration and morphology of zircons and their spatial distribution patterns this zircon based analytical method also serves as a means for reconstructing volcanic ash fall dispersal patterns the results demonstrate that zircons from claystones of two different origins i e tonstein and non cineritic claystone differ greatly in their relative abundances crystal morphologies and spatial distribution patterns tonsteins from the same area but from different horizons are characterized by their own unique statistical patterns in terms of zircon concentration values and morphologic parameters crystal length width and the ratio of these values thus facilitating stratigraphic correlation zircons from the same tonstein horizon also show continuous variation in these statistical patterns as a function of areal distribution making it possible to identify the main path and direction in which the volcanic source materials were transported by prevailing winds

regional and global benthic δ18o stacks for the last glacial cycle although detailed age models exist for some marine sediment records of the last glacial cycle 0 150 ka age models for many cores rely on the stratigraphic correlation of benthic 18o which measures ice volume and deep ocean temperature change the large amount of data available for the last glacial cycle offers the opportunity to improve upon previous benthic 18o compilations such as the lr04 global stack not only are the age constraints for the lr04 stack now outdated but a single global alignment target neglects regional differences of several thousand years in the timing of benthic 18o change during glacial terminations here we present regional stacks that characterize mean benthic 18o change for 8 ocean regions and a volume weighted global stack of data from 263 cores age models for these stacks are based on radiocarbon data from 0 to 40 ka correlation to a layer counted greenland ice core from 40 to 56 ka and correlation to radiometrically dated speleothems from 56 to 150 ka the regional 18o stacks offer better stratigraphic alignment targets than the lr04 global stack and furthermore suggest that the lr04 stack is biased 1 2 kyr too young throughout the pleistocene finally we compare global and regional benthic 18o responses with sea level estimates for the last glacial cycle

organic content and preservational controls in surficial shelf and slope sediments from the arabian sea pakistan margin abstract in the arabian sea organic rich deposits occur on the continental slope at depths roughly coincident with the impingement of an intense water column oxygen minimum zone omz this relationship has often been taken as causal and such deposits are often proposed as modern analogues of organic rich facies from the palaeorecord however there are numerous other potential preservational controls on continental margins and their relative importance remains unclear and much debated we report the results of organic inorganic and stable c isotope analyses on surficial sediments from three transects of the pakistan margin ranging in depth from well above to well below the omz organic carbon c org and total nitrogen n total contents show expected mid slope maxima although these do not mirror bottom water dissolved o 2 profiles maximal values are observed near the lower boundary of the omz or even in homogenous sediments below it together lignin yields and 13 c org values indicate a general paucity of terrigenous organic matter om this information combined with c org n total relationships suggests that the om contents of all sediments are dictated by differing accumulation of a predominant marine fraction while there are no obvious redox related differences in c org n total or om hydrogen richness across the margin there are clear minima in 13 c org within the omz in apparent contradiction with maximal accumulation of marine om the latter phenomenon is ascribed either to local source effects such as variable algal isotopic signatures or to differences in om preservation state possibly linked to bottom water redox conditions this remains to be clarified but along with the rough correspondence between mid slope sedimentary c org maxima and bottom water o 2 minima may indicate that o 2 availability is an important factor in determining sedimentary om content on this margin however evidence from redox sensitive indicators i c org mn al for persistent accumulation of om rich deposits under oxidizing conditions in homogeneous sediments below the omz clearly indicates that o 2 availability is not the sole or over riding control on om distributions

geochemistry of trace elements in chinese coals a review of abundances genetic types impacts on human health and industrial utilization abstract china will continue to be one of the largest coal producers and users in the world the high volume of coal use in china has focused attention on the amounts of toxic trace elements released from coal combustions and also the valuable trace elements extracted or potentially utilized from coal ash compared to world coals chinese coals have normal background values for most trace elements with the exception of higher li 31 8 g g zr 89 5 g g nb 9 44 g g ta 0 62 g g hf 3 71 g g th 5 84 g g and rare earth elements la lu y 136 g g this is not only due to the higher ash yields of chinese coals but also to alkali volcanic ashes found in some southwestern coals the background values of toxic elements of hg 0 163 g g as 3 79 g g and f 130 g g in chinese coals are comparable to coals from most other countries the genetic types for trace element enrichment of chinese coals include source rock controlled marine environment controlled hydrothermal fluid controlled including magmatic low temperature hydrothermal fluid and submarine exhalation controlled subtypes groundwater controlled and volcanic ash controlled the background values of trace elements were dominated by sediment source regions low temperature hydrothermal fluid was one of the major factors for the local enrichment of trace elements in southwestern china serious human health problems caused by indoor combustion of coal in china include endemic fluorosis arsenosis selenosis and lung cancer endemic fluorosis mainly occurring in western guizhou was mostly attributed to the high fluorine in clay that was used as a briquette binder for fine coals in addition to a small quantity of fluorine from coal fluorine in the coal from endemic fluorosis areas of western guizhou is within the usual range found in china and the world endemic arsenosis in southwestern guizhou is attributed to indoor combustion of high as coal endemic selenosis in enshi of hubei was due to high se in carbonaceous siliceous rocks and carbonaceous shales fine particles of quartz released into air during coal combustion are hypothesized as a possible cause for the lung cancer epidemic in xuanwei yunnan china valuable elements including ge ga u ree rare earth element nb zr and re are concentrated to levels comparable to conventional economic deposits in several coals or coal bearing strata in china the ge deposits at lincang yunnan province and wulantuga inner mongolia have been exploited and industrially utilized the enrichment of ge in the two deposits was caused by hydrothermal fluids associated with adjacent granitoids the ga al ore deposit in the jungar coalfield inner mongolia was derived from the neighboring weathered and oxidized bauxite of the benxi formation pennsylvanian the nb ta zr hf ree ga deposits in the late permian coal bearing strata of eastern yunnan and chongqing of southwestern china were attributed to ashes of the alkali volcanic eruptions

an integrated view of inorganic and organic biogeochemical indicators of palaeoproductivity changes in a coastal upwelling area in order to evaluate the role of the continental margin areas in the changes of atmospheric co2 during past climatic cycles it is crucial to reconstruct reliably export palaeoproductivity changes in such areas this paper examines and discusses the specific relationships between various productivity dependent geochemical signals recorded in a single sediment core from the northwestern africa continental slope including both major and trace parameters of inorganic and organic origin this paper clearly shows that the export productivity flux as well as its composition e g the relative contribution of calcareous siliceous and mineral free producers have changed these changes have subsequently modified benthic conditions which can have had in turn a retroaction on major biogenic element contents this effect seems however to be only minor compared to that one directly induced by changes in biogenic fluxes these results indicate that direct palaeoproductivity transfer functions which are based on present day statistical calibrations of one single parameter and which are valid to some extent for sediments from abyssal open ocean cannot be properly applied in marginal areas which are much more complex and in particular highly affected by sea level changes in such areas quantitative palaeoproductivity reconstructions should be only considered at a regional scale including off shoreward on shoreward and latitudinal migration or extension of the productive areas as well as the palaeoproductivity intensity and composition

spatiotemporal evolution of upwelling regime along the western coast of the iberian peninsula 1 the spatial and temporal variability of upwelling regime along the western coast of the iberian peninsula ip has been analyzed by means of two different but complementary databases quikscat satellite database which is available from mid 1999 with a high spatial resolution 0 25 0 25 and pacific fisheries environmental laboratory pfel database with a coarser spatial resolution 1 1 but extending back to 1967 the combined use of both databases allows determination of the spatial variability of ekman transport and pumping and identification of temporal trends in upwelling signal upwelling favorable conditions are observed during spring and summer apart from this well known seasonality on upwelling regime along the western coast of the ip some other features have been identified 1 upwelling occurs simultaneously along the entire western coast of the ip but is undoubtedly more complex closer to particular features of the shoreline 2 positive ekman pumping is more intense near capes sao vicente and rocha during spring summer and near cape finisterre all over the year 3 more favorable upwelling conditions have been observed in february and november during the last decade this result is corroborated by sea level pressure composites which show the existence of abnormally high pressures close to the ip during the last decade compared to the historical records 1948 2006 4 the decadal variability of ui is higher in autumn winter than in spring summer 5 monthly upwelling trends indicate a weakening in upwelling intensity during most of the year with the exception of february june and july

petrography and geochemistry of tonsteins from the 4th member of the upper triassic xujiahe formation in southern sichuan province china petrographic and geochemical studies on five layers of tonsteins from the 4th member of the upper triassic xujiahe formation t3xj4 in the southern sichuan province of china are presented in this paper the results suggest that these tonsteins were derived from synsedimentary acid volcanic ash fallout which was subsequently altered into relatively pure kaolinitic rocks through hydrolysis and diagenesis in a peat bog environment for definition of tonsteins refer to geol soc am spec pap 285 1993 the petrographic texture is mainly of dense and granular types with a subordinate crystalline type each tonstein layer is characterized by its unique petrographic texture mineral content and assemblage of lithophile elements which is related to the composition of its parent magma the trace element geochemistry of these tonsteins is elaborated in this paper which also suggests an origin as silicic volcanic ash fallout typically these features are relatively consistent within the same tonstein layer over a broad lateral extent and are characteristic of each specific tonstein layer therefore some tonsteins in this region serve as distinct marker beds for correlation of coal seams within the framework of regional chronostratigraphy

the gephyrocapsa sea surface palaeothermometer put to the test comparison with alkenone and foraminifera proxies off nw africa abstract recently a new palaeotemperature proxy was developed based on the morphology of the coccolithophore genus gephyrocapsa here we apply and validate this new methodology by comparing gephyrocapsa derived palaeotemperature estimates with temperature estimates obtained from alkenone ratios mg ca ratios in foraminiferal calcite and planktic foraminifera assemblages we investigated a downcore record off cape blanc geob 1048 20 55 n 19 43 w spanning the last 28 000 years in the vicinity of bofs core 31k 19 00 n 20 10 w for which a detailed multiproxy palaeotemperature record has already been established our data show an especially good correspondence between the gephyrocapsa and alkenone derived palaeotemperatures and thus validate the great potential of the new gephyrocapsa proxy to reconstruct sea surface water temperatures ssts both indicate a glacial drop in sst of 3 c compared to holocene values similar to the mg ca palaeotemperature record although the latter is consistently 2 5 c cooler largest discrepancies both in terms of downcore amplitude changes and same age sample estimates are found with available planktic foraminifera transfer function data this can be due to fundamental differences in the season of production ecologic preferences and habitats and or preservation on the other hand it may be a result of differences inherent to the transfer functions used and their original calibration i e regional vs global approach or different temperature ranges covered in addition to the downcore record off cape blanc sediment samples corresponding to the last glacial maximum lgm were selected from a dispersed set of eighteen well dated gravity cores in order to derive palaeo sst maps off northwest africa during this time slice by applying a regional gephyrocapsa transfer function for the first time we show that mean ssts in the canary islands region during the lgm were 4 6 c colder than today we found lowest glacial temperatures 14 15 5 c offshore morocco and south of the volcanic canary islands likely due to intensified upwelling related to stronger trade winds consistent with estimates from climap and other palaeotemperature reconstructions for the same region in contrast for offshore cape blanc today s centre of perennial upwelling our temperature estimates for the lgm are significantly warmer t today lgm 2 5 4 c than proposed by climap t today lgm 6 10 c however our results consistently support temperature reconstructions based on alkenones that also indicate rather small temperature changes t today lgm 2 4 c in this area we show that gephyrocapsa morphotypes may also provide useful qualitative information about relative changes in primary productivity although no linear relationship is apparent in summary our palaeotemperature and palaeoproductivity data support the observation that enhanced glacial productivity appears geographically limited to the northernmost latitudes of the nw african upwelling system whilst upwelling intensity off cape blanc was reduced despite overall enhanced trade wind intensity

partitioning of elements and macerals during preparation of antaibao coal abstract analyses of the macerals ash sulfur and 43 major and trace elements were performed on samples of feed coal cleaned coal middlings and slime collected from the antaibao coal preparation plant china and also on samples from coal preparation experiments this study is focused on the partitioning of elements and macerals during coal preparation and potential environment aspects of the elements the conclusions are as follows 1 in comparison with the feed coal the cleaned coal has a higher vitrinite content and relatively lower inertinite and exinite contents whereas the middlings and slime have lower vitrinite and exinite contents and relatively higher inertinite contents the vitrinite contents in the size segregated cleaned coals were observed to show a slightly increasing tendency with increasing particle size while the inertinite contents decreased 2 physical coal cleaning is not only effective for removal of ash and sulfur but also in reducing the concentration of most elements as cd co cs hg fe k mg nb and ni are observed to show a high degree of removal while br be cu u mn zn and organic sulfur are enriched in the cleaned coal and show a lower degree of removal the large sized cleaned coal is cleaner than the smaller sized fractions 3 the middlings especially the slime are enriched in s hg cr v zn etc so that these fractions should not be directly used as fuel in addition the concentration of pb and v in the process water exceeds the limit of relevant environmental water quality standard consequently it is necessary to develop new processes to remove ash sulfur and hazardous trace elements to the maximum extent further studies on deep processing of the middlings and slime and cleaning of the process water should also be performed

interpretation of the paleo primary production record in the nw african coastal upwelling system as potentially biased by sea level change 1 using a regional circulation ecosystem model subject to a set of boundary conditions that reflect present day pd and last glacial maximum lgm conditions we investigate how changes in preformed subsurface nutrient concentrations as opposed to a local drop in sea level or increase in wind stress influence the biological productivity off the northwest african coastal upwelling area a reduction of subsurface nutrient concentration at lgm reduced the zonally averaged primary production pp the sea level change modifies the shelf morphology the upwelling circulation and the productivity and displaces the high productivity zone according to our model results the sedimentary record of pp is best explained by a simulation considering a doubled wind stress over nw africa we conclude that production regionally along the coast of nw africa during the lgm may have been lower than today despite the fact that most of the sediment cores north of 22 n show local increases in pp during the last glacial period this paradox may be due to the sea level change and the associated eastward shift of the coastline and upwelling system

factors affecting the geochemistry of a thick subbituminous coal bed in the powder river basin volcanic detrital and peat forming processes abstract the inorganic geochemistry and mineralogy of three cores from the anderson dietz 1 coal bed a 15 2 m thick subbituminous coal bed in the tongue river member paleocene of the fort union formation were examined 1 to determine if the cores could be correlated by geochemical composition alone over a total distance of 2 km and 2 to identify the major factors that influenced the geochemistry of the coal bed chemical data 46 elements on a coal ash basis for 81 coal samples and 4 carbonaceous rock samples with most samples representing a 0 6 m thick 2 ft interval of core were grouped into compositional clusters by means of cluster analysis seven major clusters were produced two of these clusters can be used to correlate the coal bed throughout the study area data from scanning electron and optical microscope analyses indicate that several factors influenced the geochemistry of the anderson dietz 1 coal bed the majority of mineral grains in the coal bed are interpreted to be detrital water borne evidence includes the presence of rounded to subrounded quartz grains having two phase aqueous fluid inclusions characteristic of hydrothermal or low to moderate grade metamorphic quartz these quartz grains are found throughout the coal bed but are most abundant in samples from the midpart of the bed which was influenced by detrital input associated with the deposition of the clastic rocks that form the split between the anderson and dietz 1 coal beds 900 m to the east of the study area in addition to the detrital minerals mentioned above volcanic ash that was fluvially transported to the sites of peat deposition or possibly deposited as air fall volcanic ash also affected the geochemistry of the coal bed for example crandallite a mineral reported to form as an alteration product of volcanic ash is found in seven samples from the coal bed the presence of quartz grains containing silicate melt inclusions in eight samples from the coal bed provides further support for a volcanic ash component other factors that probably affected the geochemistry of the coal bed include 1 detrital input associated with the deposition of the roof rocks of the coal bed 2 peat forming processes and plant material and 3 epigenetic ground water flow

seawater ph pco2 and co2 3 variations in the caribbean sea over the last 130 kyr a boron isotope and b ca study of planktic foraminifera abstract here a new analytical methodology is described for measuring the isotopic composition of boron in foraminifera using multicollector inductively coupled plasma mass spectrometry mc icpms this new approach is fast 10 samples analysed in duplicate per analytical session and accurate to better than 0 25 at 95 confidence with acceptable sample size requirements 1 3 mg of carbonate a core top calibration of several common planktic and two benthic species from geographically widespread localities shows a very close agreement between the isotopic composition measured by mc icpms and the isotopic composition of b oh 4 in seawater as predicted using the recently measured isotopic equilibrium factor of 1 0272 at the depth of habitat a down core and core top investigation of boron concentration b ca ratio shows that the partition coefficient is influenced by co2 3 complicating the application of this proxy nevertheless it is demonstrated that these two proxies can be used to fully constrain the carbonate system of surface water in the caribbean sea odp site 999a over the last 130 kyr this reconstruction shows that during much of the holocene and the last interglacial period surface water at site 999a was in equilibrium with the atmosphere with respect to co2 during the intervening colder periods although the surface water pco2 was lower than the holocene it was a minor to significant source of co2 to the atmosphere possibly due to either an expansion of the eastern equatorial atlantic upwelling zone or a more local expansion of coastal upwelling in the southern caribbean such reorganisation of the oceanic carbonate system in favour of a larger source of co2 to the atmosphere from the equatorial ocean may require mechanisms responsible for lowering atmospheric co2 during glacial periods to be more efficient than previously supposed

geochemistry of radioactive elements u th in coal and peat of northern asia siberia russian far east kazakhstan and mongolia abstract geochemistry of radioactive elements in more than 5000 coal and peat samples of northern asia has been investigated by quantitative methods such as the instrumental neutron activation analysis the method of delayed neutrons and the x ray fluorescence analysis the average u content in the coals of deposits and basins of the region ranges from 0 6 to 32 8 ppm and for th from 0 8 to 9 2 ppm within the boundaries of basins deposits and some coal beds lateral and vertical changes of the distribution of radioactive elements have been studied the high concentrations of u and th in coal deposits are spatially related to rock blocks within the basin frames which are enriched in elements or are connected with a volcanism of a period of coal formation a consistent changing of the role of pyroclastic material in the radioactive elements accumulation was determined in the direction from the west to the east

changes in biological productivity along the northwest african margin over the past 20 000 years the intertropical convergence zone and the african monsoon system are highly sensitive to climate forcing at orbital and millennial timescales both systems influence the strength and direction of the trade winds along northwest africa and thus directly impact coastal upwelling sediment cores from the northwest african margin record upwelling related changes in biological productivity connected to changes in regional and hemispheric climate we present records of 230th normalized biogenic opal and corg fluxes using a meridional transect of four cores from 19 n 31 n along the northwest african margin to examine changes in paleoproductivity since the last glacial maximum we find large changes in biogenic fluxes synchronous with changes in eolian fluxes calculated using end member modeling suggesting that paleoproductivity and dust fluxes were strongly coupled likely linked by changes in wind strength opal and corg fluxes increase at all sites during heinrich stadial 1 and the younger dryas consistent with an overall intensification of the trade winds and changes in the meridional flux gradient indicate a southward wind shift at these times biogenic fluxes were lowest and the meridional flux gradients were weakest during the african humid period when the monsoon was invigorated due to precessional changes with greater rainfall and weaker trade winds over northwest africa these results expand the spatial coverage of previous paleoproxy studies showing similar changes and they provide support for modeling studies showing changes in wind strength and direction consistent with increased upwelling during abrupt coolings and decreased upwelling during the african humid period

uranium series ages of corals sea level history and palaeozoogeography canary islands spain an exploratory study for two quaternary interglacial periods abstract we present the first u series ages of corals from emergent marine deposits on the canary islands deposits at 20 m are 481 39 ka possibly correlative to marine isotope stage or mis 11 while those at 12 and 8 m are 120 5 0 8 ka and 130 2 0 8 ka respectively correlative to mis 5 5 the age elevations and uplift rates derived from mis 5 5 deposits on the canary islands allow calculations of hypothetical palaeo sea levels during the mis 11 high sea stand estimates indicate that the mis 11 high sea stand likely was at least 9 m relative to present sea level and could have been as high as 24 m the most conservative estimates of palaeo sea level during mis 11 would require an ice mass loss equivalent to all of the modern greenland and west antarctic ice sheets the more extreme estimates would require additional ice mass loss from the east antarctic ice sheet extralimital southern species of mollusks found in both mis 11 and mis 5 5 deposits on the canary islands imply warmer than modern sea surface temperatures during at least a part of mis 11 and much warmer sea surface temperatures during at least a part of mis 5 5 both mis 11 and mis 5 5 marine deposits on the canary islands contain extralimital northern species of mollusks as well indicating cooler than present waters at times during these interglacial periods we hypothesize that the co occurrence of extralimital southern and northern species of marine invertebrates in the fossil record of the canary islands reflects its geographic location with respect to major synoptic scale controls on climate and ocean currents previous interglacials may have been characterized by early insolation forced warming along with northward migration of the intertropical convergence zone itcz accompanied by weakened trade winds and diminished upwelling this allowed the arrival of extralimital southern taxa from the tropical senegalese faunal province during later parts of the mis 11 and 5 5 interglacials decreased insolation may have resulted in southward migration of the itcz strengthened trade winds and re establishment of upwelling such conditions may have brought about not only local extinction of the senegalese fauna but allowed southward migration of the cooler water mediterranean fauna to the canary islands in the later parts of interglacials a complex palaeoclimate record that is mirrored in the deep sea core record

petrology mineralogy and geochemistry of the lower cretaceous oil prone coal and host rocks from the laoheishan basin northeast china abstract the coal and host rocks mainly oil shale partings in the laoheishan basin ne china are oil prone this study uses petrological mineralogical and geochemical analyses to determine the reasons of high oil yield in the coal and the origin and modes of occurrence of the minerals and elements in the coal and oil shale partings the obtained data show that this sub bituminous b coal has higher oil yield av 10 than oil shale partings av 5 7 consistent with a higher hydrogen content in the coal this oil prone coal has potential for comprehensive utilization due to the relatively high gross calorific value av 17 23 mj kg in the semi coke the maceral composition suggests that the relatively high hydrogen content in the coal is mainly caused by higher resinite content palynological analysis of coal and oil shale partings mainly proved the presence of gymnosperms and ferns revealing that the paleovegetation is dominated by lygodiacean osmundacean ground ferns and cupressaceaen taxodiaceaen canopy trees these canopy trees would have provided abundant hydrogen rich components e g resin to the paleomire all the identified sporopollen suggests a warm humid subtropical paleoclimate minerals in the coal include kaolinite quartz illite and or illite smectite chlorite feldspar calcite and traces of pyrite rutile and zircon similar to the oil shale partings most of the minerals quartz feldspar clay minerals rutile and zircon occur in layers within detrovitrinite and probably are of detrital origin pyrite and calcite are of epigenetic origin and probably derived from hydrothermal fluids compared with average chinese coal the laoheishan coal is enriched in zr nb in and sb zirconium and nb mainly occur in zircon indium is both organically and inorganically associated whereas antimony largely occurs in pyrite rey rare earth elements and yttrium distribution patterns of coals and oil shale partings are dominated by heavy rey enrichment whereas roof and floor samples are medium rey enriched the m hrey enrichment is probably caused by low temperature hydrothermal fluids the sedimentary input is the major controlling factor of geochemical patterns in coal and host rocks the source rocks are probably felsic intermediate igneous rocks from the surrounding basement as indicated by relatively high al2o3 tio2 ratios 7 38 cross plot between zr ti and nb y negative eu anomalies 0 28 0 96 the presence of k feldspar and plagioclase and lithic fragment types such as granite and andesite in the samples in addition source rocks of sediments have caused high zr and nb concentrations in the coal

younger dryas style cooling events at glacial terminations i vi at odp site 658 associated benthic δ13c anomalies constrain meltwater hypothesis high resolution planktonic and epibenthic stable isotope records from ocean drilling program site 658 off northwest africa provide a basis for a detailed study of glacial terminations i vi during the last 650 000 years the duration of the terminations was about one half to one quarter of an orbital precession cycle 5800 10 700 years when its amplitude was high at low amplitudes the terminations lasted longer than half an obliquity cycle 29 000 years marked climatic rebounds similar to the younger dryas each with a duration of 1000 2500 years subdivided all six terminations into distinct steps a b and c important parts of the deglacial steps were as brief as 700 1000 years the speed of climatic change suggests that special associations existed between orbital forcing and inherent instability of the ice sheets in harmony with published models the more rapid pulses of glacial meltwater incursions to the northern north atlantic led to one or more brief short term shut downs of north atlantic deep water formation this process is reflected by pronounced benthic 13c minima that precisely coincide in most cases with the end of the 18o deglaciation steps and immediately terminate with succeeding younger dryas style cooling events thus we conclude that the rebounds resulted from a short term antecedent estuarine circulation regime in the north atlantic except for the younger dryas itself which succeeded the allerod with its well ventilated atlantic deepwater circulation and hence continues to be an enigma

assessment of geochemical and micropaleontological sedimentary parameters as proxies of surface water properties in the canary islands region abstract the canary islands region occupies a key position with respect to biogeochemical cycles with the zonal transition from oligotrophic to nutrient rich waters and the contribution of saharan dust to the particle flux we present the distribution of geochemical proxies toc carbonate 15n 13corg c n ratio and micropaleontological parameters diatoms dinoflagellates foraminifera pteropods in 80 surface sediment samples in order to characterise the influence of coastally upwelled water on the domain of the subtropical gyre results of the surface sediment analyses confirmed the high biomass gradient from the coast to the open ocean inferred from satellite data of surface chlorophyll or sst the distribution of total dinoflagellate cysts the planktic foraminifera species globigerina bulloides the diatom resting spore chaetoceros spp and toc concentration coincided well with the areas of strong filament production off cape ghir and cape yubi the warm water planktic foraminifera globigerinoides ruber white the diatom nitzschia spp and the 15n values showed the opposite trend with high values in the open ocean factor analyses on the planktic foraminifera species distribution indicated three major assemblages in the canary islands region that represent the present surface water conditions from the upwelling influenced region via a mixing area towards the subtropical gyre

arsenic and lead concentrations in the pond creek and fire clay coal beds eastern kentucky coal field abstract the middle pennsylvanian breathitt formation westphalian b pond creek and fire clay coal beds are the 2 largest producing coal beds in eastern kentucky single channel samples from 22 localities in the pond creek coal bed were obtained from active coal mines in pike and martin countries kentucky and a total of 18 fire clay coal bed channel samples were collected from localities in the central portion of the coal field the overall objective of this study was to investigate the concentration and distribution of potentially hazardous elements in the fire clay and pond creek coal beds with particular emphasis on as and pb 2 elements that are included in the 1990 clean air act amendments as potential air toxics the 2 coals are discussed individually as the depositional histories are distinct the fire clay coal bed having more sites where relatively high s lithologies are encountered in an effort to characterize these coals 40 whole channel samples excluding 1 cm partings were analyzed for major minor and trace elements by x ray fluorescence and proton induced x ray emission spectroscopy previously analyzed samples were added to provide additional geographic coverage and lithotype samples from one site were analyzed in order to provide detail of vertical elemental trends the as and pb levels in the fire clay coal bed tend to be higher than in the pond creek coal bed one whole channel sample of the fire clay coal bed contains 1156 ppm as ash basis with a single lithotype containing 4000 ppm as ash basis most of the as and pb appears to be associated with pyrite which potentially can be removed in beneficiation particularly coarser pyrite disseminated finer pyrite may not be completely removable by cleaning in the examination of pyrite conducted in this study it does not appear that significant concentration of as or pb occurs in the finer pyrite forms the biggest potential problem of as or pb enriched pyrite is therefore one of refuse disposal

glacial to interglacial changes in carbonate and clay sedimentation in the atlantic ocean estimated from 230th measurements abstract the cause of the climatically controlled fluctuations in the carbonate content of deep sea sediments remains the subject of uncertainty and debate three variables are involved supply of biogenic carbonate loss by dissolution and dilution by non carbonate phases it is suggested that 230 th which is produced in the ocean at a constant rate provides a reliable reference for measuring variations in rate of sedimentation on a regional scale results of a preliminary analysis based on published data indicate that for depths at and above the lysocline the carbonate fluctuations observed in cores from the north atlantic ocean are due primarily to variations in the terrigenous clay input which was 2 5 times higher during glacials than during interglacials carbonate deposition appears to have been somewhat reduced during glacials but probably not by more than a factor of 2 from published 230 th 232 th profiles it appears that the south atlantic ocean also received increased inputs of terrigenous clay during glacial periods

the record of triassic charcoal and other evidence for palaeo wildfires signal for atmospheric oxygen levels taphonomic biases or lack of fuel abstract as wildfires are today important sources of disturbance in many terrestrial ecosystems it is of great interest to understand how different environmental parameters and fire activity interacted during past periods of the earth history fossil charcoal inertinites and pyrogenic polycyclic aromatic hydrocarbons pahs represent the only direct evidence for the occurrence of such palaeo wildfires in the present study a review of published data together with new data on the occurrence of fossil charcoal for the permian and the triassic is presented for a long time it has been speculated that an assumed lack of evidence for palaeo wildfires during the triassic should be explained by a large drop in atmospheric oxygen concentration following or during the end permian mass extinction event preventing the occurrence of wildfires however evidence for palaeo wildfires is relatively common in many middle and late triassic strata whereas such evidence is almost totally lacking from early triassic sediments the interpretation of this charcoal gap or depression is difficult as many factors e g atmospheric oxygen concentration taphonomical biases lack of sediments suitable for the preservation of macroscopic charcoal lack of fuel and ignorance of scientists may have influenced not only the production but also the preservation and recovery of evidence for palaeo wildfires during this period thus it is not clear whether this early triassic charcoal gap can also be seen as evidence for an assumed wildfire gap or not without any doubt further investigations on the early triassic record of charcoal and other evidence for palaeo wildfires will be necessary before this problem can be solved in fact it can be expected that the number of published records of early triassic evidence for palaeo wildfires will increase in the future as more and more scientist working on sediments of this age may become aware of the interest in fires from this time this will certainly make it possible to give a much better picture of the temporal and regional distribution of wildfires during this period in the future

frequency and timing of landslide triggered turbidity currents within the agadir basin offshore nw africa are there associations with climate change sea level change and slope sedimentation rates abstract older sequence stratigraphic models suggested that submarine landslide and turbidite activities are greatest during sea level lowstands however growing evidence indicates that many turbidite systems are also active during sea level transgressions and highstands the moroccan turbidite system comprises three depocentres of which agadir basin is closest to the moroccan slope and canary archipelago the very large volumes of sediment transported by individual sediment flows in this system suggest that they are triggered by landslides extensive core coverage and dating control for the agadir basin deposits have provided an excellent opportunity to derive accurate records of turbidite and associated landslide frequency for the last 600 ka previous studies in the more distal madeira abyssal plain depocentre have indicated that large volume 50 km 3 turbidites occurred at oxygen isotope stage ois boundaries this study of agadir basin confirms that two major turbidites beds a5 and a12 occurred during glacial interglacial transitions associated with ois4 and ois6 however this association is based on just two examples and two other large volume turbidites beds a7 and a11 did not occur at a stage boundary the main conclusion of this study is that 90 of turbidites and landslides occurred during rising and high sea level which represents 40 of the total time during the last 600 ka only 10 of the turbidites and landslides occurred during glacials 40 of the time with a paucity of turbidites and landslides at peak glacial lowstands a comparison to sediment accumulation rates in the source area of the turbidite suggests that landslides did not occur preferentially during periods of more rapid sedimentation rate although sedimentation rates in this area only varied from 4 to 6 g cm 2 ka 1

nw african climate variations during the last 47 000years evidence from organic walled dinoflagellate cysts nw african climate shows orbital and millennial scale variations which are tightly connected to changes in marine productivity we present an organic walled dinoflagellate cyst dinocyst record from a sediment core off cape yubi at about 27 n in the canary basin covering the time period from 47 to 3 ka before present bp the dinocyst record reflects differences in upwelling intensity and seasonality as well as the influence of fluvial input sea level changes play an important role for the upwelling pattern and productivity signals at the core site within the studied time interval four main phases were distinguished 1 from 45 to 24 ka bp when sea level was mostly about 75 m lower than today high relative abundances of cysts of heterotrophic taxa point to enhanced upwelling activity especially during heinrich events while relatively low dinocyst accumulation rates indicate that filament activity at the core location was strongly reduced 2 at sea level lowstand during the lgm to h1 dinocyst accumulation rates suggest that local filament formation was even more inhibited 3 from the early holocene to about 8 ka bp extraordinary high accumulation rates of most dinocyst species especially of lingulodinium machaerophorum suggest that nutrient supply via fluvial input increased and rising sea level promoted filament formation at the same time the upwelling season prolongated 4 a relative increase in cysts of photoautotrophic taxa from about 8 ka bp onwards indicates more stratified conditions while fluvial input decreased our study shows that productivity records can be very sensitive to regional features from the dinocyst data we infer that marine surface productivity off cape yubi during glacial times was within the scale of modern times but extremely enhanced during deglaciation

barium peaks at glacial terminations in sediments of the equatorial atlantic ocean relicts of deglacial productivity pulses in sediment cores recovered from oligotrophic settings of the western and eastern north equatorial atlantic ocean ceara rise and sierra leone rise distinct peaks of excess barium were detected at glacial interglacial transitions these ba maxima are unrelated to any other potential productivity proxy e g organic carbon carbonate or opal moreover they coincide with minima in organic carbon contents despite the lack of correlation between excess barium and organic carbon we ascribe these ba spikes to pulses of productivity that occurred during glacial interglacial transitions the discrepancy between barium and organic carbon in these transitional sediment intervals is attributed to the action of downward progressing oxidation fronts during deglacial nonsteady state depositional conditions the oxidation fronts were initiated due to the overall low sedimentation rates prevailing in the study areas and an increase in bottom water oxygen concentrations at the onset of enhanced nadw production during interglacial periods the fronts led to a very efficient oxidation of the organic carbon initially present leaving peaks in solid phase barium as relicts of these short time productivity events this assumption is supported by the depth arrangement of the solid phase peaks of ba fe and mn along the 6 5 oxygen isotope stage boundary in sediments of the ceara rise which show striking similarities to the distribution of these elements in oxidized sapropel intervals in eastern mediterranean sediments it remains unclear whether productivity was proportional to the magnitude of the baexcess maxima possibly higher dissolved ba concentrations in intermediate and deep waters during glacial interglacial transitions caused the precipitation of barite to increase out of proportion of the postulated deglacial productivity pulses

the eastern boundary current system between the canary islands and the african coast to study the easternboundarycurrentsystem off northwest africa in detail several ctd adcp sections and long term mooring work were carried out in the channel between lanzarote and africa the observations are compared with a fine resolution model which was developed in the framework of the canigo project the water masses which are observed in this area are characterised and classified in density ranges the current field shows a high spatial and temporal variability with maximum velocities of about 35 cm s seasonal means as well as currents averaged across the channel are only a few cm s in the surface water a steady southward flow in the middle of the channel indicates the canarycurrent in this area during fall a strong northward current is observed close to the african shelf though the canarycurrent strengthens during summer and fall due to an increase of the trade winds the transport in the channel decreases or turns northward during that time due to the enhanced poleward current at the eastern side a northward undercurrent with a mean velocity of 2 3 cm s is observed at the african slope in 950 m depth the poleward transport of aaiw increases during fall and a strong influence of relatively fresh aaiw is observed during that time most of the observations fit well to the results of the canigo model but the occurrence of mw at the bottom of the channel and the corresponding southward flow cannot be resolved by the model

reconstruction of paleoceanography off nw africa during the last 40 000 years influence of local and regional factors on sediment accumulation abstract a set of 43 sediment cores from around the canary islands is used to characterise this region which intersects meridional climatic regimes and zonal productivity gradients in a high spatial resolution using rapid and nondestructive core logging techniques we carried out fe intensity and magnetic susceptibility ms measurements and created a stack on the basis of five stratigraphic reference cores for which a stratigraphic age model was available from 18 o and 14 c analyses on planktonic foraminifera by correlation of the stack with the fe and ms records of the other cores we were able to develop age depth models at all investigated sites of the region we present the bulk sediment accumulation rates ar of the canary islands region as an indicator of shifts in the upwelling influenced areas for the holocene 0 12 ky the deglaciation 12 18 ky and the last glacial 18 40 ky general observations are an enhanced productivity during glacial times with highest values during the deglaciation the main differences between the analysed time intervals we interpret as result of the sea level effects changes in the extent of high productivity areas and current intensity

paleohydrology and paleoclimatology off northwest africa during the last glacial interglacial transition and the holocene palynological evidences abstract pollen and dinoflagellate cyst analyses of deep sea core located off morocco provide a continuous record of paleoclimatic and paleohydrological change off northwestern africa since the last glacial episode the stratigraphy is given by isotopic analysis 18 o of planktonic foraminifera which shows a two step deglaciation xeric conditions on the adjacent land marked by the increase of steppe taxa artemisia chenopodiaceae amaranthaceae ephedra and the development of the montane taxon cedrus atlantica are observed before termination ia and during the younger dryas these intervals are also marked by a high abundance of pinus pollen grains which indicates a strengthening of the northeastern ne trade winds variations of the surface water temperatures are shown by the fluctuations of dinoflagellate cyst assemblages which reflect a cooling of the surface waters during termination ia and the younger dryas episode intensification of the upwelling system off morocco resulting from enhanced trade winds occurred during these two key periods quercus forests which are an important part of the present day vegetation of the maghreb region developed around 8500 yr b p dinoflagellate cyst assemblages suggest that present day oceanic conditions were established during this period

upwelling intensity and ocean productivity changes off cape blanc northwest africa during the last 70 000 years geochemical and micropalaeontological evidence abstract the accumulation of biogeochemical organic carbon calcium carbonates molybdenum and iodine micropalaeontological benthic foraminifera and terrigenous markers grain size si al zr al k al over the last 70 000 years in one core sedorqua 11k on the northwest african margin off cap blanc has been used to reconstruct past variations of local upwelling intensity and oceanic productivity the study demonstrates that productivity in this area increased during stage 3 particularly between 40 000 and 50 000 yr b p and during the last deglaciation between 6000 and 15 000 yr b p during most of isotopic stage 2 and particularly during the last glacial maximum productivity was much lower these variations can be attributed to changes in local wind stress and seasonality that are related to variability in monsoon pressure intensity because of the establishment of upwelling cells over the shelf due to high sea level the conditions of sedimentation during the last 5 6 thousend years on the upper slope site 11k are largely dominated by advection from the shelf leading to strong sorting prior to deposition advection seems to have been minor during the other periods of enhanced productivity a conceptual model is proposed to link the productivity variations to atmospheric circulation in particular to the wind stress direction and seasonality

geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the antaibao mining district shanxi china twenty six samples including roof bottom and coal plies of a marine influenced coal bed were collected from the antaibao mining district shanxi china the rare earth elements rees were determined in solids and organic solvent extracts the distribution pattern showed three distinct patterns shale like lree rich and hree rich this is attributed to the variable microenvironment of peat forming swamp the degree of marine influences and different ree sources rees in the coal are mainly controlled by detrital minerals but also affected by seawater the chondrite normalized ree patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples which show a negative eu anomaly a depletion of middle rees and an enrichment of hrees the lrees in coal extracts are likely adsorbed by hydrogen containing functional groups and hrees are likely bonded to carbon atoms

coal petrography mineralogy elemental compositions and palaeoenvironmental interpretation of late carboniferous coal seams in three wells from the kozlu coalfield zonguldak basin nw turkey abstract a number of coal seams of late carboniferous age in the coal bearing karadon kozlu and alacaagzi formations have been mined in several deep underground mines in the zonguldak basin nw turkey for this study a total of 154 coal core samples were collected from three research wells that were drilled in the tectonically complex settings of the kozlu coalfield all the coal samples were studied by means of coal petrography mineralogy and geochemistry special attention was given to the compositions and origins of fracture cleat filling minerals that were identified by sem edx on polished blocks the coal seams investigated are of bituminous rank they are characterized by low total sulphur contents 1 0 on dry basis and high gross calorific values 22 5 40 2 mj kg on dry ash free basis whereas ash yields and volatile matter contents are variable x ray powder diffraction data indicate that the mineralogical compositions of the studied coal seams are rather similar and clay minerals along with quartz and carbonate minerals were identified in almost all seams the statistical evaluations and sem data show that some elements such as mg ti zr nb and th are generally affiliated with silicate minerals whereas elements like cu zn mo and pb are mainly associated with sulphide minerals the silicate minerals are generally detrital and the majority of carbonate minerals are of epigenetic origin the epigenetic carbonate and sulphide minerals suggest that circulated solutions within coal seams were mainly derived from ca2 rich solutions leached from overlying formations such as cretaceous aged zonguldak formations and from hydrothermal solutions that likely were derived from andesitic dykes within the basin the regional tectonic activities during coalification seem to have deformed coal bearing formations and therefore intra basinal solutions could have penetrated into the studied coal seams the epigenetic mineralisation also resulted in elemental enrichments and elevated ash yields total sulphur and volatile matter contents in some coal seams thus deformation during coalification controlled some coal quality parameters in the studied wells the coal facies diagrams suggest that palaeomires mostly accumulated under limno telmatic conditions whereas a telmatic environment was more common in palaeomires of the kozlu formation coal petrography suggests that peat forming vegetation and water tables in palaeomires were changeable during the late carboniferous

temperature and productivity changes off the western iberian margin during the last 150 ky abstract present day hydrographic conditions along the western iberian margin are characterized by seasonal upwelling with filaments that can penetrate more than 200 km into the open ocean and constitute areas of cold and highly productive waters in order to investigate spatial and temporal gradients in temperature and productivity conditions during the last 150 ky high resolution proxy records were generated in 3 cores su92 03 md95 2040 md95 2042 located along the iberian coast between 43 12 n and 37 48 n and forming a n s profile in all cores planktonic foraminifera census counts are used to reconstruct summer sea surface temperature sstsu and export productivity pexpsu using the modern analog technique simmax 28 sstsu and pexpsu values similar to the present are observed throughout the holocene and mis 5e periods for each site respectively indicating fairly stable conditions equivalent to the modern ones on glacial interglacial timescales sstsu increases by 2 3 c from the northern to southernmost site pexpsu on the other hand shows a decrease of 30 40 gc m2 yr from north to south at present time and during interglacial periods and no significant variation 90 100 gc m2 yr during glacial periods the northernmost core su92 03 reveals the coldest conditions with records more similar to md95 2040 than to md95 2042 the later of which is as at present more affected by subtropical waters core su92 03 shows higher interglacial productivity similar to open ocean mid to high latitude sites while the other two cores monitor higher glacial productivity conform with other upwelling sites off nw africa a boundary between differences in glacial interglacial productivity appears to be present in our study between 43 12 n and 40 35 n especially north of 40 n coldest sstsu and lowest pexpsu are found during heinrich events h 1 h8 and h10 h11 in contrast lowest pexpsu do not coincide with these events at site md95 2042 but appear to be related to the presence of relatively warm and nutrient poor subtropical eastern north atlantic central water advected with the azores current

mineralogy and geochemistry of a late permian coal in the dafang coalfield guizhou china influence from siliceous and iron rich calcic hydrothermal fluids abstract this paper describes the influence of siliceous and iron rich calcic low temperature hydrothermal fluids lthf on the mineralogy and geochemistry of the late permian no 11 coal anthracitic r r 2 85 in the dafang coalfield in northwestern guizhou province china the no 11 coal has high contents of vein ankerite 10 2 vol and vein quartz 11 4 vol with formation temperatures of 85 and 180 c respectively indicating that vein ankerite and vein quartz were derived from low temperature calcic and siliceous hydrothermal fluids in two epigenetic episodes the vein quartz appears to have formed earlier than vein ankerite did and at least three distinct stages of ankerite formation with different ca sr and fe mn ratios were observed the two types of mineral veins are sources of different suites of major and trace metals scanning electron microscope and sequential extraction studies show that in addition to fe mg and ca vein ankerite is the dominant source of mn cu ni pb and zn in the coal and the contents of these five elements are as high as 0 09 and 74 0 33 6 185 and 289 g g respectively in contrast vein quartz is the main carrier mineral for platinum group elements pges pd pt and ir in the coal and the contents of pd pt and ir are 1 57 0 15 and 0 007 g g respectively sequential extraction showed a high pge content in the silicate fraction up to 10 4 g g pd 1 23 g g pt and 0 05 g g ir respectively it is concluded that the formation of ankerite and quartz and the anomalous enrichment of trace elements in the no 11 coal in the dafang coalfield guizhou result from the influx of calcic and siliceous low temperature hydrothermal fluids

lanthanide yttrium and zirconium anomalies in the fire clay coal bed eastern kentucky abstract the fire clay coal bed in the central appalachian basin region contains a laterally persistent tonstein that is found in the coal throughout most of its areal extent the tonstein contains an array of minerals including sanidine quartz anatase and euhedral zircon that constitutes strong evidence for a volcanic origin of the parting for this study five samples of the tonstein and four sets of coal samples underlying the tonstein were collected from five sites in eastern kentucky inductively coupled plasma mass spectroscopy icp ms analysis of the tonstein and underlying coal collected from four sites in eastern kentucky show that although zr concentrations are high in the tonstein 570 1820 ppm on a coal ash basis cab they are highest in the coal directly underlying the tonstein 2870 4540 ppm cab a similar enrichment pattern is observed in the concentration of y plus the sum of the rare earth elements y ree total y ree concentrations in the five tonstein samples range from 511 to 565 ppm cab however y ree contents are highest in the coals directly underlying the tonsteins values range from 1965 to 4198 ppm cab scanning electron microscopy of samples from coal which directly underlies two of the tonstein samples show that ree rich phosphate tentatively identified as monazite commonly infills cracks in clays and cells in clarain and vitrain zircon is rare and commonly subhedral on the basis of coal chemistry and grain morphology we suggest that volcanic components in the tonstein were leached by ground water the leachate rich in y and ree precipitated as authigenic mineral phases in the underlying coal

geochemical and mineralogical anomalies of the late permian coal in the zhijin coalfield of southwest china and their volcanic origin abstract this paper describes the influence of volcanic ash on the concentrations and occurrences of associated elements in coal in the zhijin coalfield in western guizhou province china our studies reveal that the no 9 coal seam in the zhijin coalfield has very high content of fe 4 34 cu 369 90 g g u 49 6 g g mo 63 10 g g zn 33 97 g g and zr 841 80 g g the studies have also found that elements such as fe and cu do not occur as sulfides in this coal seam in sharp contrast to many other coal seams in china the geochemical and mineralogical anomalies of the coal seam are attributed to synsedimentary volcanic ash in addition to normal macerals and minerals in coal a volcanic influenced material vim derived from volcanic ash detrital material of terrigenous origin and organic matter was identified under polarized light reflectance microscopy and scanning electron microscopy equipped with energy dispersive x ray edx analyzer the volcanic influenced material is the main carrier of the above elements in this coal six types of the volcanic influenced material vim 1 vim 2 vim 3 vim 4 vim 5 and vim 6 are further distinguished on the basis of their structures and compositions to the best of our knowledge this is the first report that presents a detailed classification of coal components with a high content of volcanic ash

glacial interglacial variability of particle accumulation in the canary basin a time slice approach abstract particle supply and sediment accumulation in the canary basin are strongly modified by seasonal coastal upwelling and dust input from the sahara along an e w depth profile and fertility gradient north of the canary islands we demonstrate an increase in total mass accumulation rates from a low of 1 2 g cm 2 ka 1 in the outer oceanic domain to 6 12 g cm 2 ka 1 closer to the moroccan shelf in holocene sediments during the last glacial maximum lgm oxygen isotopic event 2 2 a steeper gradient was found with two to four times higher mass accumulation rates at the near shore sites total mass accumulation rates during the last interglacial climax lic isotopic event 5 5 and end of the penultimate glaciation epg isotopic event 6 2 resemble holocene values with lowered near shore maxima of 3 and 4 g cm 2 ka 1 respectively analyses of separate sediment components show that total organic carbon total carbonate lithogenic and diatom accumulation rates were generally enhanced during glacial times especially during the lgm in contrast glacial accumulation rates of biogenic carbonate particles coccoliths and planktic foraminifera shells remained constant or were lowered with respect to interglacial time periods at the site closest to the moroccan shelf despite a doubling of bulk carbonate accumulation this could indicate lowered supply from the productive euphotic zone or a latitudinal offshore shift of the main sedimentary depocentre however enhanced carbonate dissolution could by itself account for this decrease in biogenic carbonate accumulation increased glacial input of detrital carbonate derived from the exposed moroccan shelf appears to be responsible for the overall enhanced carbonate accumulation at the same sites east of lanzarote