records of post cretaceous tertiary boundary millennial scale cooling from the western tethys a smoking gun for the impact winter hypothesis the record of both dinoflagellate cysts and benthic foraminifera across the cretaceous tertiary boundary at el kef tunisia reveals a brief expansion of the boreal bioprovince into the western tethys suggesting that an 2 k y cooling occurred during the earliest danian we show that this prolonged cooling phase is consistent with the oceanographic response to an impact winter

specific surface area and pore size distribution in clays and shales one of the biggest challenges in estimating the elastic transport and storage properties of shales has been a lack of understanding of their complete pore structure the shale matrix is predominantly composed of micropores pores less than 2 nm diameter and mesopores pores with 2 50 nm diameter these small pores in the shale matrix are mainly associated with clay minerals and organic matter and comprehending the controls of these clays and organic matter on the pore size distribution is critical to understand the shale pore network historically mercury intrusion techniques are used for pore size analysis of conventional reservoirs however for unconventional shale reservoirs very high pressures 414 mpa 60 000 psi would be required for mercury to access the full pore structure which has potential pitfalls current instrumental limitations do not allow reliable measurement of significant portions of the total pore volume in shales nitrogen gas adsorption techniques can be used to characterize materials dominated by micro and mesopores 2 50 nm a limitation of this technique is that it fails to measure large pores diameter 200 nm we use a nitrogen gas adsorption technique to study the micro and mesopores in shales and clays and compare the results from conventional mercury porosimetry techniques our results on pure clay minerals and natural shales show that i they have a multiscale pore structure at different dimensions ii fine mesopores with a characteristic 3 nm pore size obtained with n2 gas adsorption are associated with an illite smectite group of clays but not with kaolinite iii compaction results in a decrease of pore volume and a reduction of pore size in the inter aggregate macropores of the illitesmectite clays while the fine intra tachoid mesopores are shielded from compaction iv for natural shales mineralogy controls the pore size distributions for shales and the presence of micropores and fine mesopores in natural shales can be correlated with the dominance of the illite smectite type of clays in the rock our assessment of incompressible 3 nm sized pores associated with illite smectite clays provides an important building block for their mineral modulus

robust multi proxy data integration using late cretaceous paleotemperature records as a case study abstract in paleoclimate studies multiple temperature records are often compared and combined to evaluate temperature trends yet no standardized approach for integrating proxy derived paleotemperature records exists in addition paleotemperature data are often reported without uncertainty estimates prediction errors and raw data are not always available this complicates the quantification of for example temperature trends and the magnitude of warming events here we propose a robust quantitative approach for multi proxy analysis in paleoclimate studies to demonstrate this we study the latest maastrichtian warming event lmwe in the odp 174ax bass river core new jersey and integrate five independent paleotemperature proxies covering the last million years of the cretaceous our integrated temperature reconstruction suggests that after a climatically stable period a latest cretaceous warming of 3 9 1 1 c occurred between 450 and 100 kyr before the k pg boundary the error on this reconstructed temperature should be considered the absolute minimum error as poorly constrained or unknown uncertainties cannot be fully propagated the warming event was followed by a gradual cooling to pre warming conditions towards the end of the cretaceous furthermore the record suggests multiple warming pulses during the lmwe the results of this integrated approach are consistent with other latest cretaceous temperature records suggesting that the trend described here represents a global signal

intermittent euxinia in the high latitude james ross basin during the latest cretaceous and earliest paleocene abstract seymour island in the james ross basin antarctica contains a continuous succession of latest cretaceous sediments deposited in a shallow marine environment at high latitude making it an ideal place to study environmental changes prior to the k pg mass extinction we measured major and trace elements and conducted petrographic analysis of two sections from the maastrichtian danian lopez de bertodano formation of seymour island several lines of evidence point to intermittently anoxic to euxinic conditions during deposition including the presence of pyrite framboids with a size distribution suggesting syngenetic formation in the water column and enrichments in several trace elements including molybdenum arsenic copper zinc and chromium molybdenum enrichments are clearly associated with enrichments in manganese and authigenic iron suggesting shuttling of redox sensitive trace elements across a chemocline that fluctuated across the sediment water interface comparisons with modern systems suggest relatively high frequency redox variability possibly over approximately annual timescales which may be related to the annual cycle of polar sunlight and associated seasonal changes in primary productivity glauconitic horizons are associated with more reducing conditions including at the k pg boundary though this does not appear to be a uniquely euxinic interval similar degrees of trace element enrichment are seen in other highly glauconitic intervals while euxinia may have contributed to low diversity in the lowermost rotularia units redox conditions do not seem to have been the primary control on the transition to a mollusc dominated fauna in the latest maastrichtian redox conditions show little to no response to the eruption of the deccan traps or maastrichtian climatic changes instead intermittent euxinia appears to have been a characteristic feature of this high latitude environment during the cretaceous paleogene transition

impure co2 reaction of feldspar clay and organic matter rich cap rocks decreases in the fraction of accessible mesopores measured by sans abstract during co2 geological storage low porosity and permeability cap rock can act as a structural trap preventing co2 vertical migration to overlying fresh water aquifers or the surface clay and organic matter rich shales fine grained sandstones and mudstones often act as cap rocks and may contain substantial sub micron porosity co2 brine rock interactions can open or close pore throats through dissolution precipitation or migration of clay fines or grains this could affect co2 migration if the porosity is accessible with unchanging or decreasing accessible porosity favourable for trapping and integrity two cap rock core samples a clay and organic rich mudstone and a more organic lean feldspar rich fine grained sandstone from a well drilled for a co2 storage feasibility study in australia were experimentally reacted with impure co2 so2 o2 and low salinity brine at reservoir conditions mercury injection capillary pressure indicated that the majority of pores in both cores had pore throat radii 5 150 nm with porosities of 5 5 8 4 after reaction with impure co2 brine the measured pore throats decreased in the clay rich mudstone core dissolution and precipitation of carbonate and silicate minerals were observed during impure co2 reaction of both cores via changes in water chemistry scanning electron microscopy identified macroporosity in clays mica and amorphous silica cements after impure co2 brine reaction precipitation of barite fe oxides clays and gypsum was observed ion leaching from fe rich chlorite was also apparent with clay structural collapse and fines migration small angle neutron scattering measured the fraction of total and non accessible pores 10 150 nm radii pores before and after reaction the fraction of pores that was accessible in both virgin cap rocks had a decreasing trend to smaller pore size the clay rich cap rock had a higher fraction of accessible pores 0 9 at the smallest sans measured pore size than the feldspar rich fine grained sandstone 0 75 both core samples showed a decrease in sans accessible pores after impure co2 water reaction at co2 storage conditions the clay rich cap rock showed a more pronounced decrease after impure co2 brine reaction the fraction of accessible pores at the smallest pore size was 0 85 in the clay rich cap rock and 0 75 in the feldspar rich fine grained sandstone reactions during impure co2 brine rock reaction have the potential to close cap rock pores which is favourable for co2 storage integrity

on the causes of mass extinctions the temporal link between large igneous province lip eruptions and at least half of the major extinctions of the phanerozoic implies that large scale volcanism is the main driver of mass extinction here we review almost twenty biotic crises between the early cambrian and end cretaceous and explore potential causal mechanisms most extinctions are associated with global warming and proximal killers such as marine anoxia including the early middle cambrian the late ordovician the intra silurian intra devonian end permian and early jurassic crises many but not all of these are accompanied by large negative carbon isotope excursions supporting a volcanogenic origin most post silurian biocrises affected both terrestrial and marine biospheres suggesting that atmospheric processes were crucial in driving global extinctions volcanogenic atmospheric kill mechanisms include ocean acidification toxic metal poisoning acid rain and ozone damage and consequent increased uv b radiation volcanic darkness cooling and photosynthetic shutdown each of which has been implicated in numerous events intriguingly some of the most voluminous lips such as the oceanic plateaus of the cretaceous were emplaced with minimal faunal losses and so volume of magma is not the only factor governing lip lethality the missing link might be continental configuration because the best examples of the lip extinction relationship occurred during the time of pangaea many of the proximal kill mechanisms in lip extinction scenarios are also potential effects of bolide impact including cooling warming acidification and ozone destruction however the absence of convincing temporal links between impacts and extinctions other than the chicxulub cretaceous example suggests that impacts are not the main driver of extinctions with numerous competing extinction scenarios and the realisation that some of the purported environmental stresses may once again be driving mass extinction we explore how experimental biology might inform our understanding of ancient extinctions as well as future crises

the importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs abstract the effect of shale composition and fabric upon pore structure and ch 4 sorption is investigated for potential shale gas reservoirs in the western canadian sedimentary basin wcsb devonian mississippian d m and jurassic shales have complex heterogeneous pore volume distributions as identified by low pressure co 2 and n 2 sorption and high pressure hg porosimetry thermally mature d m shales 1 6 2 5 vro have dubinin radushkevich d r co 2 micropore volumes ranging between 0 3 and 1 2 cc 100 g and n 2 bet surface areas of 5 31 m 2 g jurassic shales which are invariably of lower thermal maturity ranging from 0 9 to 1 3 vro than d m shales have smaller d r co 2 micropore volumes and n 2 bet surface areas typically in the range of 0 23 0 63 cc 100 g co 2 and 1 9 m 2 g n 2 high pressure ch 4 isotherms on dried and moisture equilibrated shales show a general increase of gas sorption with total organic carbon toc content methane sorption in d m shales increases with increasing toc and micropore volume indicating that microporosity associated with the organic fraction is a primary control upon ch 4 sorption sorption capacities for jurassic shales however can be in part unrelated to micropore volume the large sorbed gas capacities of organic rich jurassic shales independent of surface area imply a portion of ch 4 is stored by solution in matrix bituminite solute ch 4 is not an important contributor to gas storage in d m shales structural transformation of d m organic matter has occurred during thermal diagenesis creating and or opening up microporosity onto which gas can sorb as such d m shales sorb more ch 4 per weight percent wt toc than jurassic shales inorganic material influences modal pore size total porosity and sorption characteristics of shales clay minerals are capable of sorbing gas to their internal structure the amount of which is dependent on clay type illite and montmorillonite have co 2 micropore volumes of 0 78 and 0 79 cc 100 g n 2 bet surface areas of 25 and 30 m 2 g and sorb 2 9 and 2 1 cc g of ch 4 respectively dry basis a reflection of microporosity between irregular surfaces of clay platelets and possibly related to the size of the clay crystals themselves mercury porosimetry analyses show that total porosities are larger in clay rich shales compared to silica rich shales due to open porosity associated with the aluminosilicate fraction clay rich sediments low si al ratios have unimodal pore size distributions

timing and climate forcing of volcanic eruptions for the past 2 500 years volcanic eruptions contribute to climate variability but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual to decadal temperature variability in the northern hemisphere during the past 2 500 years our results are based on new records of atmospheric aerosol loading developed from high resolution multi parameter measurements from an array of greenland and antarctic ice cores as well as distinctive age markers to constrain chronologies overall cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth century pandemics famines and socioeconomic disruptions in eurasia and mesoamerica while allowing multi millennium quantification of climate response to volcanic forcing

relationship between mass extinction and iridium across the cretaceous paleogene boundary in new jersey we directly link iridium ir anomalies in new jersey to the mass extinction of marine plankton marking the cretaceous paleogene k pg boundary we confirm previous reports of an ir anomaly 20 cm below the extinction of cretaceous macrofauna the pinna bed with new results from a muddy sand section from tighe park freehold new jersey united states but we also show that ir anomalies correlate with marine mass extinctions at three other clay rich new jersey sections thus we attribute the anomaly at freehold to the downward movement of ir and reaffirm the link between impact and mass extinction

characterizing long term co2 water rock reaction pathways to identify tracers of co2 migration during geological storage in a low salinity siliciclastic reservoir system abstract given the prevailing use of saline reservoirs for geological co 2 storage projects limited data are available on the geochemical evolution of formation water chemistry during geological co 2 storage in low salinity formations the low salinity total dissolved solids 2 storage comprising three major siliciclastic formations with distinctly different mineral compositions contrasts in the geochemical responses of jurassic sequence core samples have been identified during short term co 2 water rock experiments conducted under co 2 storage conditions farquhar et al in this issue if persistent such contrasts may serve as geochemical tracers of co 2 migration within the surat basin here we use a combined batch experiment and numerical modeling approach to characterize the long term response of the jurassic succession to storage and migration of co 2 and to assess reaction pathway sensitivity to co 2 partial pressure reservoir system mineralogy was characterized for 66 core samples from geological survey of queensland stratigraphic well chinchilla 4 and six representative samples were powdered and reacted with synthetic formation water and high purity co 2 for up to 27 days at a range of pressures formation water alkalinity offers limited buffering at elevated co 2 pressures and ph rapidly declines resulting in sustained enhancement of mineral dissolution rates batch reactor results exhibit regional groundwater like 87 sr 86 sr values 0 7048 0 7066 less radiogenic than whole rock results 0 7085 indicating incongruent dissolution of the reservoir matrix carbonate and authigenic clay dissolution are expected to be the primary reaction pathways regulating long term formation water composition during geological co 2 storage in the surat basin with lesser contributions from dissolution of the clastic matrix

six decades of glacier mass balance observations a review of the worldwide monitoring network glacier mass balance is the direct and undelayed response to atmospheric conditions and hence is among the essential variables required for climate system monitoring it has been recognized as the largest non steric contributor to the present rise in sea level six decades of annual mass balance data have been compiled and made easily available by the world glacier monitoring service and its predecessor organizations in total there have been 3480 annual mass balance measurements reported from 228 glaciers around the globe however the present dataset is strongly biased towards the northern hemisphere and europe and there are only 30 reference glaciers that have uninterrupted series going back to 1976 the available data from the six decades indicate a strong ice loss as early as the 1940s and 1950s followed by a moderate mass loss until the end of the 1970s and a subsequent acceleration that has lasted until now culminating in a mean overall ice loss of over 20 m w e for the period 1946 2006 in view of the discrepancy between the relevance of glacier mass balance data and the shortcomings of the available dataset it is strongly recommended to 1 continue the long term measurements 2 resume interrupted long term data series 3 replace vanishing glaciers by early starting replacement observations 4 extend the monitoring network to strategically important regions 5 validate calibrate and accordingly flag field measurements with geodetic methods and 6 make systematic use of remote sensing and geo informatics for assessment of the representativeness of the available data series for their entire mountain range and for the extrapolation to regions without in situ observations and 7 make all these data and related meta information available

automated mapping of earth s annual minimum exposed snow and ice with modis global snow and ice have been diminishing during theanthropocenebutwestilllackacompletemappingofannualminimumexposedsnowandicewithaconsistent repeatablealgorithm the global land ice measurements from space glims project has compiled digital glacier outlines andrelated metadata for the majority of the world s glaciers butinconsistency among product algorithms and time periodsrepresented precludes the production of a consistentlyderived global data set here we present the modis persis tent ice modice algorithm that leverages the time seriesof fractional snow and ice cover from the modis snowcovered area and grain size modscag algorithm theend product of modice is a consistently derived map ofannual minimum exposed snow and ice comparisons ofmodice with glims glacier outlines derived from spot aster and landsat thematic mapper show strong agree ment with the higher resolution outlines subject to uncer tainties with spatial resolution deep mountain shadows andglims interpretation errors

rapid short term cooling following the chicxulub impact at the cretaceous paleogene boundary the mass extinction at the cretaceous paleogene boundary 66 ma is thought to be caused by the impact of an asteroid at chicxulub present day mexico although the precise mechanisms that led to this mass extinction remain enigmatic most postulated scenarios involve a short lived global cooling a so called impact winter phase here we document a major decline in sea surface temperature during the first months to decades following the impact event using tex86 paleothermometry of sediments from the brazos river section texas we interpret this cold spell to reflect to our knowledge the first direct evidence for the effects of the formation of dust and aerosols by the impact and their injection in the stratosphere blocking incoming solar radiation this impact winter was likely a major driver of mass extinction because of the resulting global decimation of marine and continental photosynthesis

experimental evaluation of mixed fluid reactions between supercritical carbon dioxide and nacl brine relevance to the integrity of a geologic carbon repository abstract the reactive behavior of a mixed fluid supercritical co2 and brine under physical chemical conditions relevant to geologic storage and sequestration in a carbon repository is largely unknown experiments were conducted in a flexible cell hydrothermal apparatus to evaluate fluid rock aquifer plus aquitard reactions that may adversely impact the integrity of the repository a 5 5 molal nacl brine rock system was held at 200 c and 200 bars 20 mpa for 32 days 772 h to approach steady state then injected with co2 and allowed to react for an additional 45 days 1079 h in a separate experiment at 200 c and 200 bars the system was allowed to react for 77 days 1845 h without injection of co2 corroded magnesite and euhedral siderite crystallized in a paragenetic sequence after co2 injection nucleation and growth of siderite on shale suggests the aquitard is a reactive component in the system changes in elemental abundances in the brine following addition of co2 include ph decrease and depletion of sodium due to accelerated growth of analcime a ph increase follows pressure and temperature decrease and loss of saturated co2 from acidic brine silica concentrations and dissolution rates are enhanced and silica precipitation inhibited in the acidic brine geochemical reactions in a carbon repository extend beyond ph decrease and carbonate mineral precipitation rock dominated reaction systems yield to acid dominated and related reactions controlled by mixed fluid equilibria i e a fluid dominated system escape of co2 or migration of brine from the repository into overlying aquifers may cause silica super saturation and increased alkalinity due to mixed fluid phase equilibria these geochemical changes could be monitored in aquifers as indicators of repository integrity return of silica super saturated brine to a rock dominated reaction system buffered to neutral ph conditions may enhance precipitation of quartz chalcedony or amorphous silica in addition to the potential effects beneficial or deleterious that silica super saturation and precipitation may hold for repository performance an understanding of the effects of multi phase equilibrium relationships between supercritical co2 and dissolved silica in aquifer brine systems also raises new questions for a variety of geologic systems multi phase fluid equilibria may for example account for quartz cements in some sedimentary basin sandstones and quartz vein mineralization in some ore districts

a 220 year continuous record of volcanic h2so4 in the antarctic ice sheet continuous h2so4 profiles observed in snow from several antarctic locations reveal four major volcanic events of the past two centuries agung krakatoa tambora and another large scale event not recorded historically acid deposition and interhemispheric distribution mechanisms are quantified and then used to obtain an order of magnitude estimate for the h2so4 emissions from these eruptions

the chicxulub asteroid impact and mass extinction at the cretaceous paleogene boundary the cretaceous paleogene boundary similar to 65 5 million years ago marks one of the three largest mass extinctions in the past 500 million years the extinction event coincided with a large asteroid impact at chicxulub mexico and occurred within the time of deccan flood basalt volcanism in india here we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction notably a single ejecta rich deposit compositionally linked to the chicxulub impact is globally distributed at the cretaceous paleogene boundary the temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations for example darkness and cooling lead us to conclude that the chicxulub impact triggered the mass extinction

metal release from limestones at high partial pressures of co2 abstract co 2 leakage from underground co 2 sequestration and storage poses potential risks to degradation of water quality in shallow aquifers increased co 2 concentrations can result in decreased ph and lead to subsequent metal release from mineral dissolution or desorption from mineral surfaces dissolution of carbonate minerals present in aquifer sediments or rocks will buffer ph and is generally thought to reduce the potential risk of metal release in the event of a co 2 leak as a result much of the research on geochemical impacts of co 2 leakage has focused on siliciclastic aquifers with little to no carbonate minerals present however carbonate minerals contain trace amounts of metals in their crystal structure that will be released into solution with dissolution and may pose a risk to drinking water quality here we perform laboratory water rock experiments to analyze the potential for metal release due to carbonate mineral dissolution in limestone aquifers rock samples from three limestone aquifers were dissolved in batch reactors with varying partial pressures of co 2 from 0 01 to 1 bar in the headspace as co 2 dissolved into the fluid and decreased the ph the carbonate minerals dissolved and released metals into solution the concentrations of calcium magnesium strontium barium thallium uranium and cobalt increased but remained below any regulatory limits the concentrations of arsenic and nickel increased and exceeded primary drinking water standards set by the usepa and the state of california respectively potential sources of metals in the rocks were determined through detailed sample characterization using sequential extractions laser ablation inductively coupled mass spectrometry and high resolution mineralogical mapping with qemscan we found that calcite dissolution released more metals to solution than pyrite dissolution or metal desorption from mineral surfaces in these experiments geochemical models based on the experimental data were used to evaluate the relative importance of calcite dissolution versus pyrite dissolution over a 30 year time frame under both oxic and sub oxic conditions calcite dissolution is the dominant source of metals to solution immediately after exposure to co 2 pyrite dissolution becomes the dominant source at later times as the fluid reaches equilibrium with respect to calcite for all model scenarios the cumulative contribution of metals to solution was dominated by calcite dissolution results from this study suggest that the ph buffering benefit of carbonate mineral dissolution in the event of a co 2 leak may be offset by the potentially negative effect of trace metal release from the crystal structure this study highlights the need for detailed sample characterization at individual sites to identify sources of metals when assessing the potential risk of co 2 leakage into shallow aquifers

geochemical and geomechanical effects of scco2 and associated impurities on physical and petrophysical properties of permotriassic sandstones germany an experimental approach effects of impurities sox nox and o2 from the extraction processes of the power plants in the scco2 fluids are studied with an experimental approach combining geochemical alteration in high p medium t autoclaves compressional tests in a heated triaxial testing device as well as geochemical and mineralogical analyses before and after the influences of distinct scco2 fluids on 140 70 mm sized samples of reservoir sandstones from the north german basin with carbonate cementation silicate cementation and a combined silicate carbonate cementation on the background of variable lithological compositions the attempt was made to normalize the scattering geomechanical data by the pure co2 behavior measurement data to achieve a direct impression of any differences due to the impurities changes in the chemical composition of the saline fluids were systematically measured during the scco2 alteration experiments in the autoclave systems at distinct pt conditions the development of the silica concentrations and of the ph value in the fluid solution during alteration showed a clear dependency on the fluid composition through systematical analysis of changes on the mineral surfaces using sem microscopy images before and after scco2 impurities alteration experiments or triaxial compression tests corrosion effects were detected but no differences which could be directly related to differences in the fluid composition could be identified in all the types of sandstones visible or measurable changes on mineral surfaces and pore fluid composition respectively take place as an interaction of rock with fluids of scco2 with and without impurities changing deformability and compressive strength of the rocks are the most apparent consequences due to these compositional changes it is supposed that the chemical fluid differences are responsible for these changes also a specific distribution of the different fluids in the ambient pore space is indicated with even undetected consequences for the fluid influence on stress transmission and distribution within the grain structure all work was performed within the project co2 purity for capture and storage cooral supported by the german federal ministry for economic affairs and energy

iridium profiles and delivery across the cretaceous paleogene boundary we examined iridium ir anomalies at the cretaceous paleogene k pg boundary in siliciclastic shallow marine cores of the new jersey coastal plain usa that were deposited at an intermediate distance 2500 km from the chicxulub mexico crater although closely spaced and generally biostratigraphically complete the cores show heterogeneity in terms of preservation of the ejecta layers maximum concentration of ir measured 0 1 2 4 ppb and total thickness of the ir enriched interval 11 119 cm we analyzed the shape of the ir profiles with a lagrangian particle tracking model of sediment mixing fits between the mixing model and measured ir profiles as well as visible burrows in the cores show that the shape of the ir profiles was determined primarily by sediment mixing via bioturbation in contrast tighe park 1 and bass river cores show post depositional remobilization of ir by geochemical processes there is a strong inverse relationship between the maximum concentration of ir measured and the thickness of the sediments over which ir is spread we show that the depth integrated ir inventory is similar in the majority of the cores indicating that the total ir delivery at time of the k pg event was spatially homogeneous over this region though delivered through a near instantaneous source stratospheric dispersal and settling our study shows that non uniform ir profiles develop due to changes in the regional delivery and post depositional modification by bioturbation and geochemical processes

stable climate in india during deccan volcanism suggests limited influence on k pg extinction abstract large igneous provinces lips have been temporally correlated to mass extinctions throughout the phanerozoic including the emplacement of the deccan volcanic province dvp 66 3 65 6 ma in western and central india which has been invoked as either a cause or exacerbating factor in the cretaceous paleogene k pg extinction however relatively little is known about local paleoclimatic and paleoenvironmental responses to volcanism to investigate the dvp s role as a driver of local environmental change and to provide climatic background for known ecological shifts new inter basaltic paleosol profiles at the eastern edge of the dvp are used in conjunction with profiles from the literature to reconstruct paleoclimate and terrestrial environments before and after the k pg these profiles provide a novel opportunity to study the sediments within basalt flows before during and after a mass extinction event and in the midst of a lip emplacement event paleoclimate proxies and the floral humidity province proxy reflect little long term change in either climate or environment across the k pg with stable precipitation values and temperatures accompanied by a constant forest signal these interpretations are corroborated by macrofloral records and sedimentology from india which suggest some environmental turnover but generally support a forested fluvio lacustrine environment throughout the duration of volcanism our results support the possibility of rapid recovery times for terrestrial ecosystems during volcanism and suggest that while dvp eruptions may have exacerbated long term environmental perturbation the emplacement of the dvp is not likely to have caused the terrestrial mass extinction at the k pg boundary

determination of changes in the reservoir and cap rocks of the chabowo anticline caused by co2 brine rock interactions abstract the article describes the changes taking place in the rock matrix reservoir and cap rock due to the effect of carbon dioxide in the presence of brine the experiment was carried out on samples of lower jurassic sandstones reservoir rocks and claystones cap rocks from chabowo 1 and chabowo 3 boreholes chabowo anticline nw poland a potential structure for underground storage of carbon dioxide rock samples were placed for a period of 18 months in a designed apparatus system and the experiment was performed under the conditions of t 25 c and p 6 mpa by soaking the rock samples in a brine of simplified chemical composition similar to the brine present in the rock formation analysed mineral composition was determine by observation in transmitted light xrd and sem eds in order to perform the changes in the individual mineral phases using the sem eds method the results of mineralogical and petrographic observations of the same rock samples before and after the experiment are presented dissolution and precipitation processes of minerals were observed as the result of the experiment corrosion prone minerals were feldspars etchings were observed on pyrite and mica grains the dominant mineral phase formed after the experiment was halite which caused the precipitation of this mineral after the evaporation of brine precipitation of poorly developed kaolinite crystals was also observed the long term experiment conducted at low temperature and pressure showed similar changes that are obtained in the experiments carried out for the actual reservoir conditions but on a smaller scale

application of laser ablation icp ms to determine high resolution elemental profiles across the cretaceous paleogene boundary at agost spain abstract a high resolution analysis of the distribution of major and trace elements across a cretaceous paleogene boundary kpgb was done using laser ablation inductivity coupled plasma mass spectrometry la icp ms and was compared with traditional distinct sampling and analysis at the agost site se spain a 22 cm long core containing the kpgb was recovered using a rolatec rl 48l drill within this interval the lowermost 5 cm correspond to the maastrichtian and the uppermost 17 cm to the danian the core section was resin embedded under o2 free conditions cut and polished for la icp ms continuous measurements with 10 m increments and a laser beam of 80 m elemental concentrations in discrete samples taken prior to embedding from the same core interval were determined by inductivity coupled plasma optical emission spectroscopy icp oes the la icp ms analyses in continuous mode considerably improve the resolution of geochemical profiles allowing the compositional variability at a micrometer scale within the ejecta layer to be detected in this study we obtained profiles with 255 data points for the ejecta layer interval compared to 3 data points obtained by traditional manual sampling and icp oes analyses yet our recovered core section showed a rather limited preservation of the ejecta layer this paper focuses on the presentation of la icp ms analysis as a particularly useful tool to investigate paleoenvironmental changes associated with bio events additionally the high resolution of major and trace elemental distribution made it possible to study remobilization across thin but distinct boundaries such as the kpgb

palynological evidence for prolonged cooling along the tunisian continental shelf following the k pg boundary impact abstract the cretaceous palaeogene k pg boundary mass extinction event is related to major global environmental changes resulting from a large extraterrestrial impact organic walled cyst producing marine dinoflagellates dinocysts survived the k pg mass extinction relatively unscathed making them ideally suited for reconstructing these environmental changes so far one of the best dinocyst records available is from the k pg boundary global stratotype section and point gssp at el kef nw tunisia there the dinocyst record shows major fluctuations across the boundary likely reflecting strong responses to environmental changes these fluctuations have so far not been confirmed by other studies therefore in this study we performed a high resolution marine palynological study on a closely spaced sample set from the elles section some 75 km south of el kef in order to generate a palaeoenvironmental and palaeoclimatic record across the k pg boundary to allow verification and refinement of earlier reported environmental changes to better constrain the reconstructions based on qualitative biotic proxies we employed the quantitative sea surface temperature proxy tex86 unfortunately the tex86 proxy record of the studied section is compromised because of post depositional oxidation however the diverse dinocyst assemblages at elles show strong fluctuations similar to the el kef record therefore confirming the earlier recorded signals showing rapid regionally consistent changes these records imply that the latest cretaceous was characterized by a gradual cooling trend and the onset of relative sea level fall within the immediate post extinction interval in the first thousands of years after the impact dinocyst assemblages reveal multiple incursions of higher latitude dinocyst species implying repeated pulses of cooling these results signify that the earliest danian climatic and environmental conditions were relatively unstable across the tunisian shelf

the manumiella seelandica global spike cooling during regression at the close of the maastrichtian abstract manumiella seelandica lange 1969 bujak and davies 1983 emend firth 1987 occurs in great abundance together with a closely related and possibly conspecific form isabelidinium sp virtually at the end of the maastrichtian the abundance of m seelandica immediately adjacent the cretaceous paleogene kpg boundary and its global distribution serve as an excellent biostratigraphic marker for dating it the abundance spike is widely distributed in both northern and southern hemispheres and ranges from locations as far south as seymour island antarctica to as far north as west greenland the global distribution of the m seelandica spike in such widely separated areas and the ease with which it is recognized in closely sampled sections underscores its value in dating until recently this short lived event was correlated within an interval of global sea level fall and regression which extended from the latest maastrichtian into the earliest danian that is that the species became numerically abundant as the shoreline approached however based on our study of the boundary interval at bass river in southern new jersey usa we propose that an additional factor may have contributed to its origin our investigation of this section shows that there is a prominent abundance spike in the 20 cm 7 8 in interval immediately beneath the boundary and that this interval correlates precisely with the 18o isotope evidence of cooling at bass river the last 500 ky of the maastrichtian was a period of global warmth as revealed by geochemical evidence however based on the geochemical evidence a mild cooling period began within tens of thousands of years of the close of the cretaceous period based on this correlation we present the hypothesis that the cooling event played an important role in producing this global assemblage of dinoflagellates study of a large number of fossils in the sample situated 15 cm 5 85 in beneath the boundary shows that there is considerable variation in overall form and archeopyle excystment in manumiella seelandica the same degree of variation was not observed in the samples with fewer specimens

mineralogical controls on porosity and water chemistry during o2 so2 co2 reaction of co2 storage reservoir and cap rock core reservoir and cap rock core samples with variable lithology s representative of siliciclastic reservoirs used for co2 storage have been characterized and reacted at reservoir conditions with an impure co2 stream and low salinity brine cores from a target co2 storage site in queensland australia were tested mineralogical controls on the resulting changes to porosity and water chemistry have been identified the tested siliciclastic reservoir core samples can be grouped generally into three responses to impure co2 brine reaction dependent on mineralogy the mineralogically clean quartzose reservoir cores had high porosities with negligible change after reaction in resolvable porosity or mineralogy calculated using x ray micro computed tomography and qemscan however strong brine acidification and a high concentration of dissolved sulphate were generated in experiments owing to minimal mineral buffering also the movement of kaolin has the potential to block pore throats and reduce permeability the reaction of the impure co2 brine with calcite cemented cap rock core samples caused the largest porosity changes after reaction through calcite dissolution to the extent that one sample developed a connection of open pores that extended into the core sub plug this has the potential to both favor injectivity but also affect co2 migration the dissolution of calcite caused the buffering of acidity resulting in no significant observable silicate dissolution clay rich cap rock core samples with minor amounts of carbonate minerals had only small changes after reaction created porosity appeared mainly disconnected changes were instead associated with decreases in density from fe leaching of chlorite or dissolution of minor amounts of carbonates and plagioclase the interbedded sandstone and shale core also developed increased porosity parallel to bedding through dissolution of carbonates and reactive silicates in the sandy layers tight interbedded cap rocks could be expected to act as baffles to fluids preventing vertical fluid migration concentrations of dissolved elements including ca fe mn and ni increased during reactions of several core samples with mn mg co and zn correlated with ca from cap rock cores precipitation of gypsum fe oxides and clays on seal core samples sequestered dissolved elements including fe through co precipitation or adsorption a conceptual model of impure co2 water rock interactions for a siliciclastic reservoir is discussed

modeling the distribution of the volcanic aerosol cloud from the 1783 1784 laki eruption 1 we conducted simulations of the atmospheric transformation and transport of the emissions of the 1783 1784 laki basaltic flood lava eruption 64 10 n 17 15 w using the nasa goddard institute for space studies modele climate model coupled to a sulfur cycle chemistry model the model simulations successfully reproduced the aerosol clouds of the 1912 katmai and 1991 mount pinatubo eruptions giving us confidence in the laki simulations simulations of the laki eruption produce peak zonal mean sulfate so4 concentrations of over 70 ppbv during august and into september 1783 in the upper troposphere and lower stratosphere at high latitudes while the majority of the sulfate aerosol was removed during the fall and early winter a significant aerosol perturbation remained into 1784 the peak so2 gas loading was just over 37 megatons mt in late june with the sulfate loading peaking in late august 1783 at 60 mt over the average of 3 runs this yielded a peak sulfate aerosol 75 h2so4 25 h2o loading of over 80 mt with the total aerosol produced during the entire eruption being about 165 mt the resulting sulfate deposition compares well with ice cores taken across greenland the top of atmosphere net radiative forcing peaks at 27 w m2 over the high latitudes during late summer 1783 and produces a global mean forcing of 4 w m2 the model results confirm that northern hemisphere high latitude volcanic eruptions produce aerosols that remain mostly confined north of 30 n latitude

evaluation of the impact of co2 co contaminant gas aqueous fluid and reservoir rock interactions on the geologic sequestration of co2 lowering the costs of front end processes e g separation in the geologic sequestration of co2 can dramatically lower the overall costs one possible approach is to sequester less pure co2 waste streams that are less expensive or require less energy to separate from flue gas or a coal gasification process etc the objective of this research is to evaluate the impacts of co2 itself as well as an impure co2 waste stream on geologic sequestration using reaction progress models reactive transport simulators and analogous reactive transport experiments run in a plug flow reactor specifically we are investigating the potential for co injecting the sox nox and h2s present in coal fired waste streams along with the co2 we present here the results of reactive transport simulations made to investigate the long term impact of dissolved co2 h2s and so2 on carbon sequestration in the frio fm tx the results suggest that addition of relatively large amounts of h2s to a co2 injection should not adversely impact injectivity or sequestration compared to the injection of co2 alone the co injection of so2 however could produce significantly different results if conditions are such that so2 can oxidize to sulfate in the long term the simulations suggest that carbonate mineral formation can sequester a significant fraction of the injected carbon through the formation of calcite magnesite and dawsonite

experimental mineral dissolution in berea sandstone reacted with co2 or so2 co2 in nacl brine under co2 sequestration conditions a comparison of the geochemical changes induced in sandstone by either pure or impure co2 at geological co2 storage conditions was investigated samples of berea sandstone were batch reacted in 1 w v nacl brine saturated with pure co2 or mixed so2 co2 gas for 360 h at 50 degrees c and 10 mpa geochemical analysis of incremental water samples showed increases in the concentrations of elements such as calcium magnesium iron manganese and silicon throughout experiments likely being the products of carbonate and reactive silicate dissolution scanning electron microscope images taken of specific points of interest before and after batch reactions confirmed dissolution of carbonates but showed no reaction for minerals such as k feldspar the magnitude of apparent mineral reaction was higher for the mixed gas so2 co2 brine experiment with geochemical modelling also indicating greater dissolution of reactive silicates such as chlorite and potential precipitation of amorphous silica c 2014 elsevier b v all rights reserved

south pacific evidence for the long term climate impact of the cretaceous paleogene boundary event abstract the cretaceous paleogene k pg boundary is well represented across a range of depositional settings in new zealand trends in fossil assemblages and marine lithofacies indicate that the k pg event was followed by a pronounced and long term 1 myr perturbation in climate and ocean conditions these findings are supported by a tex86 derived sea surface temperature sst reconstruction across the k pg boundary at mid waipara river north canterbury the bayspar calibration indicates that sst was very stable in the uppermost cretaceous 20 c but abruptly warmed by 4 c in a 25 cm thick lowermost paleocene interval this interval is overlain by a 2 m thick interval in which sst abruptly cooled by 10 c and then progressively returned to 20 c the basal paleocene warm interval is associated with an acme in the dinoflagellate species trithyrodinium evittii and the succeeding cool interval is associated with an acme in palaeoperidinium pyrophorum biostratigraphic correlation of the shelfal mid waipara section to the pelagic k pg sections in marlborough reveals that a significant unconformity separates these two acme events with the t acme event occurring in the earliest paleocene and the p pyrophorum acme occurring 1 myr later and lasting 200 kyr a succession of dinoflagellate acme events within the intervening interval in the marlborough sections implies unstable climatic and environmental conditions in the lead up to the p pyrophorum acme and cooling event at 65 ma this event also coincides with a peak in biogenic silica accumulation in the marlborough sections we suggest that disruption to biogeochemical pathways at the k pg boundary caused long term climatic cooling in the southern pacific region

cretaceous sea surface temperature evolution constraints from tex86 and planktonic foraminiferal oxygen isotopes it is well established that greenhouse conditions prevailed during the cretaceous period 145 66 ma determining the exact nature of the greenhouse gas forcing climatic warming and climate sensitivity remains however an active topic of research quantitative and qualitative geochemical and palaeontological proxies provide valuable observational constraints on cretaceous climate in particular reconstructions of cretaceous sea surface temperatures ssts have been revolutionised firstly by the recognition that clay rich sequences can host exceptionally preserved planktonic foraminifera allowing for reliable oxygen isotope analyses and secondly by the development of the organic palaeothermometer tex86 based on the distribution of marine archaeal membrane lipids here we provide a new compilation and synthesis of available planktonic foraminiferal 18o 18opl and tex86 sst proxy data for almost the entire cretaceous period the compilation uses ssts recalculated from published raw data allowing examination of the sensitivity of each proxy to the calculation method e g choice of calibration and places all data on a common timescale overall the compilation shows many similarities with trends present in individual records of cretaceous climate change for example both sst proxies and benthic foraminiferal 18o records indicate maximum warmth in the cenomanian turonian interval our reconstruction of the evolution of latitudinal temperature gradients low 48 palaeolatitudes reveals temporal changes in the valanginian aptian the low to higher mid latitudinal temperature gradient was weak decreasing from 10 17 c in the valanginian to 3 5 c in the aptian based on tex86 ssts in the cenomanian santonian reconstructed latitudinal temperature contrasts are also small relative to modern 14 c based on low latitude tex86 and 18opl ssts minus higher latitude 18opl ssts compared with 20 c for the modern in the mid campanian to end maastrichtian latitudinal temperature gradients strengthened 19 21 c based on low latitude tex86 and 18opl ssts minus higher latitude 18opl ssts with cooling occurring at low middle and higher palaeolatitude sites implying global surface ocean cooling and or changes in ocean heat transport in the late cretaceous these reconstructed long term trends are resilient regardless of the choice of proxy tex86 or 18opl or calibration this new cretaceous sst synthesis provides an up to date target for modelling studies investigating the mechanics of extreme climates

a new glacier inventory for the svartisen region norway from landsat etm data challenges and change assessment glaciers are widely recognized as key indicators of climate change and their meltwater plays an important role in hydropower production in norway since the last glacier inventory was compiled in northern norway in the 1970s marked fluctuations in glacier length and mass balance have been reported for individual glaciers and the current overall glacier state is thus not well known within the framework of the global land ice measurements from space glims initiative we have created a new inventory for 489 glaciers in the svartisen region northern norway using a landsat enhanced thematic mapper plus etm satellite scene from 7 september 1999 and automated multispectral glacier mapping thresholded band ratios in addition visual inspection and correction of the generated glacier outlines has been applied adverse snow conditions and uncertain drainage divides made glacier mapping challenging in some regions of the study site glacier outlines from 1968 as digitized from a topographic map were used for a quantitative change assessment for a selection of 300 glaciers the overall area change of this sample from 1968 to 1999 was close to zero but with a strongly increasing scatter towards smaller glaciers large area gains 50 for small glaciers 1 km 2 and an unexpected stronger relative area loss towards the wetter coast the overall size changes are small 1 for the three largest ice masses in the study region vestisen ostisen and blamannsisen

changes in reservoir heterogeneity and quality as a response to high partial pressures of co2 in a gas reservoir new zealand abstract the kapuni field is the largest onshore petroleum field in new zealand and produces co2 rich gas c 40 45 mol co2 diagenesis within the reservoir is dominated by co2 related reactions that have resulted in localised precipitation of kaolin abundant quartz calcite dolomite and siderite along with localised generation of secondary porosity most of the co2 in the reservoir is thought to have been sourced from intraformational coals with subsequent up dip migration to the crest of the kapuni structure during migration co2 will have dissolved into undersaturated pore fluids and the resulting acidic pore fluids catalysed feldspar and minor carbonate dissolution thereby providing ions for precipitation of authigenic minerals timing of the diagenetic reactions as determined by paragenetic observations and fluid inclusion analysis suggests that both quartz and carbonate formed at a very late stage 100 c corresponding to 0 4 ma which is consistent with modelled maturation and expulsion of co2 from intraformational source rocks 5 ma to present the carbon isotope composition of carbonate cements median 13cpdb 12 4 is similar to that of the reservoired co2 13cpdb 14 5 and this is supportive of late stage cement formation with carbon sourced primarily from thermal maturation reactions the degree of co2 related reactions observed within the kapuni field appears dependent upon grain size lithofacies and stratigraphic position in the reservoir coarse grained high energy facies have undergone the most feldspar dissolution coupled with formation and local preservation of secondary porosity this is interpreted to be due to preferential migration of large volumes of co2 rich fluids through permeable beds thereby further enhancing reservoir quality by comparison much less feldspar reaction but locally significant authigenic mineral precipitation occurs within finer grained lower energy sandstone facies this is considered to be due to relatively low permeability prior to co2 circulation restricting the degree of fluid circulation and resulting in net mineral precipitation authigenic kaolin has precipitated close to the mineral source whilst ions required to precipitate calcite dolomite cements are likely to have migrated further resulting in a complex distribution of carbonate cements with pervasive cements observed at gas water contacts results from this study demonstrate how co2 related reactions are dependent on grain size and mineralogy we show that these reactions can affect vertical heterogeneity of a reservoir by increasing the degree of compartmentalisation through development of sweet spots due to mineral dissolution and tight beds due to mineral cementation

evidence for reduced export productivity following the cretaceous paleogene mass extinction the cretaceous paleogene k pg mass extinction was associated with a collapse in the carbon isotopic 13c gradient between planktonic and benthic foraminifera and a decrease in bulk carbonate 13c values these perturbations have been explained by several hypotheses global collapse of primary productivity strangelove ocean greatly reduced export but not primary productivity living ocean little or no reduction in export productivity resilient ocean and geographic heterogeneity in the change of export productivity heterogeneous ocean we tested primary versus export productivity changes in the paleoshelf of new jersey where 13c values and organic carbon accumulation rates can distinguish among different ocean responses on the shelf the k pg boundary is associated with a 2 5 13c decrease in bulk carbonate a 0 8 13c decrease in organic carbon a collapse of the surface to bottom 13c gradient and a drop in organic carbon accumulation rates we interpret an early danian 1 0 planktonic foraminiferal 13c gradient a 0 75 cross shelf benthic foraminiferal 13c gradient and a drop in carbon accumulation rates to reflect the presence of active primary but limited export productivity consistent with the living ocean hypothesis we evaluated interbasinal deep sea benthic foraminiferal 13c gradients between the pacific site 1210 and atlantic site 1262 oceans as a proxy for changes in export productivity the interbasinal 13c gradient was reduced after the mass extinction suggesting a reduction in global export productivity although our data support the living ocean hypothesis evidence from paleoupwelling zones shows significant export productivity indicating spatial heterogeneity in the wake of the k pg mass extinction heterogeneous ocean

stable isotope records across the cretaceous paleogene transition stevns klint denmark new insights from the chromium isotope system abstract late cretaceous to early paleogene time represents a critical transitional period in earth history global events include short term instability in climate and ocean circulation large igneous province emplacement and catastrophic extinction of marine and terrestrial fauna due at least in part to a bolide impact event the response of the ocean system to cretaceous paleogene k pg global events has been the subject of much research yet fundamental questions remain regarding carbon cycling climate ocean mixing and redox conditions to help elucidate paleoceanographic changes across the k pg transition we revisit the classic maastrichtian to danian chalk limestone succession at stevns klint denmark with a suite of new geochemical data including insights from the redox sensitive chromium isotope system we use carbon and oxygen isotope trends to form a well constrained framework for the succession before presenting strontium isotope chromium isotope and rare earth element data for the units deposited both before and after the k pg event carbon isotopes show only minor perturbation across the k pg boundary and oxygen isotopes record a prominent positive excursion with both of these trends standing in contrast to many k pg boundary sections worldwide strontium isotopes record a spike towards more radiogenic values which is consistent with a globally observed short term weathering pulse the chromium isotope profile of maastrichtian chalk begins with strongly positive values followed by a sharp negative excursion associated with a facies shift and initiation of bottom currents in the chalk sea 53 cr values then recover before falling steadily across the k pg boundary and into the danian limestone chromium isotope trends do not correspond to changes in hydrothermal input or basin redox conditions instead we propose that mixing of water masses with distinct chromium isotope signatures controlled temporal chromium isotope variability the local mixing event inferred from our maastrichtian chromium isotope data could be related to a temporary inflow of tethyan bottom waters or the shift from end maastrichtian greenhouse warming associated with deccan volcanism to the worldwide cooling phase that immediately preceded the k pg boundary no immediate change in chromium isotopes is recorded across the k pg boundary indicating that the bolide impactor did not substantially perturb the marine chromium cycle at least at the scale resolvable by our data instead chromium isotope trends continued to be controlled by local oceanographic processes highlighting the potential of the chromium isotope system to record isotopic heterogeneity and mixing events in ancient oceans

evidence for cretaceous paleogene boundary bolide impact winter conditions from new jersey usa abrupt and short lived impact winter conditions have commonly been implicated as the main mechanism leading to the mass extinction at the cretaceous paleogene k pg boundary ca 66 ma marking the end of the reign of the non avian dinosaurs however so far only limited evidence has been available for such a climatic perturbation here we perform high resolution tex86 organic paleothermometry on three shallow cores from the new jersey paleoshelf northeastern usa to assess the impact provoked climatic perturbations immediately following the k pg impact and to place these short term events in the context of long term climate evolution we provide evidence of impact provoked severe climatic cooling immediately following the k pg impact this so called impact winter occurred superimposed on a long term cooling trend that followed a warm phase in the latest cretaceous

a high resolution record of environmental changes from a cretaceous paleogene section of seymour island antarctica a high resolution sedimentological and palynological study was performed in combination with biomarker based organic geochemical temperature proxies tex86 and mbt cbt on a 7 4 m thick continuous section straddling the cretaceous paleogene k pg boundary at seymour island at the northern tip of the antarctic peninsula the k pg interval of the seymour island section was deposited in a deltaic estuarine system with considerable sedimentary input from the erosion of a distant volcanic arc at the antarctic peninsula combined with ash fallouts from explosive volcanic eruptions the maastrichtian interval represents the prodelta of a delta prograding in a marginal marine setting whereas the paleocene interval was deposited in more open shallow marine conditions following sea level rise and shoal submergence above the k pg boundary dinocyst biostratigraphy indicates that in the studied section the k pg boundary is represented by a gentle erosive surface 30 cm below a partially indurated marker sandstone bed the dinoflagellate assemblages show quantitative changes across the boundary representatives of manumiella group together with abundant palambages dominate the assemblages in the lower part of the section i e below the k pg boundary there is an evident peak of fibrocysta ifecysta cordosphaeridium just above the boundary in the upper part of the section senegalinium reaches relatively high abundance together with impletosphaeridium clavus while relatively high concentrations of soil derived organic matter inhibit the use of the tex86 paleothermometer to reconstruct sea surface temperatures the mbt cbt paleothermometer indicates warm mean annual air temperatures for the latest cretaceous 16 0 16 5 c these high temperatures coinciding with the lowest abundance of the high latitude pollen taxon nothofagidites may reflect the terminal cretaceous deccan traps warming pulse fluctuating temperatures followed in the early paleocene characterized by 2 degrees drop in air temperatures coincident with the maximum percentage of the high latitude angiosperm nothofagidites spp and the cold water dinocyst taxon impletosphaeridium clavus the recognition of ecological signals of disturbances and their relationship with short term climatic and environmental changes provides new insights related to the effect of the impact at the high latitude k pg boundary of antarctica

impact winter and the cretaceous tertiary extinctions results of a chicxulub asteroid impact model abstract the chicxulub impact crater in mexico is the site of the impact purported to have caused mass extinctions at the cretaceous tertiary k t boundary 2 d hydrocode modeling of the impact coupled with studies of the impact site geology indicate that between 0 4 and 7 0 1017 g of sulfur were vaporized by the impact into anhydrite target rocks a small portion of the sulfur was released as so3 or so4 which converted rapidly into h2so4 aerosol and fell as acid rain a radiative transfer model coupled with a model of coagulation indicates that the aerosol prolonged the initial blackout period caused by impact dust only if the aerosol contained impurities a larger portion of sulfur was released as so2 which converted to aerosol slowly due to the rate limiting oxidation of so2 our radiative transfer calculations combined with rates of acid production coagulation and diffusion indicate that solar transmission was reduced to 10 20 of normal for a period of 8 13 yr this reduction produced a climate forcing cooling of 300 wm 2 which far exceeded the 8 wm 2 greenhouse warming caused by the co2 released through the vaporization of carbonates and therefore produced a decade of freezing and near freezing temperatures several decades of moderate warming followed the decade of severe cooling due to the long residence time of co2 the prolonged impact winter may have been a major cause of the k t extinctions

baby it s cold outside climate model simulations of the effects of the asteroid impact at the end of the cretaceous sixty six million years ago the end cretaceous mass extinction ended the reign of the dinosaurs flood basalt eruptions and an asteroid impact are widely discussed causes yet their contributions remain debated modeling the environmental changes after the chicxulub impact can shed light on this question existing studies however focused on the effect of dust or used one dimensional noncoupled atmosphere models here we explore the longer lasting cooling due to sulfate aerosols using a coupled climate model depending on aerosol stratospheric residence time global annual mean surface air temperature decreased by at least 26 c with 3 to 16 years subfreezing temperatures and a recovery time larger than 30 years the surface cooling triggered vigorous ocean mixing which could have resulted in a plankton bloom due to upwelling of nutrients these dramatic environmental changes suggest a pivotal role of the impact in the end cretaceous extinction

3d porosity and mineralogy characterization in tight gas sandstones tight gas reservoirs exhibit storage and flow characteristics that are intimately tied to depositional and diagenetic processes as a result exploitation of these resources requires a comprehensive reservoir description and characterization program to identify properties which control production in particular tight gas reservoirs have significant primary and secondary porosity and pore connectivity dominated by clays and slot like pores this makes them particularly susceptible to the effects of overburden stress and variable water saturation this paper describes an integrated approach to describe a tight gas sandstone at the pore scale in 3d in particular the primary and secondary porosity of a tight gas sandstone are identified and quantified in three dimensions using 3d x ray micro ct imaging and visualization of core material at the pore scale 3d images allow one to map in detail the pore and grain structure and interconnectivity of primary and secondary porosity once the tomographic images ar

supercritical carbon dioxide brine rock reactions in the madison limestone of southwest wyoming an experimental investigation of a sulfur rich natural carbon dioxide reservoir abstract the madison limestone on the moxa arch southwest wyoming usa is a sulfur rich natural co 2 reservoir a series of hydrothermal experiments was performed to evaluate multi phase co 2 h 2 o brine rock reactions and processes in this reservoir and to test the hypothesis that this reservoir is a natural analog for geologic carbon sulfur co sequestration idealized madison limestone dolomite calcite anhydrite pyrite and na cl so 4 2 brine i 0 5 molal reacted at 110 c and 25 mpa for approximately 81 days 1940 h supercritical co 2 was then injected and the experiment continued for approximately 46 days 1100 h a parallel experiment was performed without supercritical co 2 to provide a basis of understanding for the interaction of supercritical co 2 with the brine rock system two additional experiments were conducted in the same manner but without anhydrite in the starting mineral assemblage to examine supercritical co 2 sulfur reactivity injection of supercritical co 2 decreases ph by 2 5 to 3 3 units increases eh by 0 19 to 0 23 v and drives reaction pathways along the pyrite anhydrite saturation boundary of an eh ph diagram the dolomite calcite anhydrite mineral assemblage and reaction textures that are produced are consistent with those observed in the natural co 2 reservoir the mineral assemblage does not change following emplacement of supercritical co 2 instead minerals dissolve mobilize and re precipitate anhydrite precipitates in the dolomite calcite pyrite experiment following injection of supercritical co 2 and provides a mineral trap for sulfur anhydrite precipitation decreases so 4 2 activity ultimately leading to mineralization of co 2 experimental results support the hypothesis that the madison limestone on the moxa arch is a natural analog for geologic carbon sulfur co sequestration

shock induced vaporization of anhydrite and global cooling from the k t impact discovery of abundant anhydrite caso 4 and gypsum caso 4 2h 2o in the otherwise carbonate sediment comprising the upper 3 km thick layer of the target rock at the k t impact site has prompted research on these minerals evaluation of the severity of the proposed extinction mechanism involving injection of impact generated so 2 and so 3 into the stratosphere entails determination of criteria for shock induced vaporization of these minerals in the present work we present new data on the vaporization criteria of anhydrite these are based on the reanalysis of the shock wave experiments of yang and ahrens earth planet sci lett 156 1998 125 140 conducted on material with 30 porosity in which the shock fully or partially vaporized sample interacts with an overlying lif window the velocity histories monitored using a velocity interferometer are compared with numerical simulations employing an improved equation of state for porous anhydrite and its vaporization products we also employ the entropy criterion for vaporization of material under shock compression the values of the entropies of incipient and complete vaporization for anhydrite are determined to be 1 65 0 12 and 3 17 0 12 kj kg k 1 respectively and the corresponding pressures for incipient and the complete vaporization along the hugoniot for the solid material are 32 5 2 5 and 122 13 gpa respectively as compared with 81 7 and 155 13 gpa previously reported by yang and ahrens along with these criteria the use of the recent estimate of diameter 100 km for the chicxulub transient crater o keefe and ahrens j geophys res 104 e11 1999 27091 27104 morgan et al nature 390 1997 472 476 that is smaller than previously assumed along with ivanov et al s geol soc am spec pap 307 1996 125 142 2 d hydrodynamic simulation to determine the shock attenuation and pope et al s j geophys res 102 e9 1997 21645 21664 radiative transfer model yields the maximum decrease in the average global surface temperature of 12 19 k for 9 0 9 5 years at the k t boundary thus the global cooling is inferred to have been less severe than that indicated by the upper limit of the range of 5 31 k decrease lasting for 12 years calculated by pope et al because ambient global surface temperatures at k t time were 18 20 c warmer than present values this cooling event produced cold but not freezing conditions at the earth s surface

isotopic analysis of sulfur cycling and gypsum vein formation in a natural co2 reservoir abstract in order to assess the long term security of geologic carbon storage it is crucial to study the geochemical behavior of sulfur in reservoirs that store co2 fossil fuel combustion may produce mixtures of carbon dioxide and sulfur gases and the geochemical effects of sulfur co2 cosequestration are poorly understood this study examines sulfur mineralization from a core drilled in a stacked sequence of natural co2 reservoirs near the town of green river utah these reservoirs include the entrada and navajo sandstone which are separated by the carmel formation caprock and transected by a system of co2 degassing normal faults through which saline co2 charged brines discharge our objective in this study is to evaluate the mechanisms and timing of secondary mineral formation particularly gypsum formation in the co2 reservoirs and intervening caprock the carmel formation contains beds of gypsum within a fault zone secondary veins of gypsum exist throughout the entrada sandstone and carmel formation we report sulfur and oxygen isotope data 34sso4 and 18oso4 respectively measured in gypsum and 34s measured in pyrite and the oxygen and hydrogen isotope composition 18o and d respectively of gypsum hydration water the multiple isotope approach allows us to trace the sources of sulfur in the reservoirs and when combined with structural and petrological evidence the progress of fluid rock reactions and relative timing of vein mineralization the secondary gypsum veins in the carmel formation derive from mixing of fluids with two isotopically distinct sulfate sources sulfate from the gypsum beds within the carmel formation and sulfate rich brines that originate from evaporites in the underlying carboniferous paradox formation the gypsum veins in the entrada sandstone have a relatively wide range of 18oso4 both isotopically more enriched in 18o and more depleted in 18o than the primary gypsum sources we suggest that some aqueous sulfate in the entrada sandstone may cycle through multiple valence states as it undergoes reduction and reoxidation resulting in the replacement of its oxygen atoms and allowing the occasional formation of gypsum with anomalous low 18oso4 our data from gypsum hydration water indicates that groups of gypsum veins formed at two different times gypsum veins in the entrada sandstone and some veins in the carmel formation likely formed during quaternary co2 charged brine discharge events while other veins located close to the gypsum beds in the carmel formation formed earlier likely during cycles of dehydration and rehydration associated with the laramide age 40 mya faulting we conclude that calcium sulfate mineral formation in brine filled fractures may play an important role in inhibiting fluid migration in geologic reservoirs that contain co2

the el chichon stratospheric cloud solid particulates and settling rates sampling of the el chichon stratospheric cloud in early may and in late july 1982 showed that a significant proportion of the cloud consisted of solid particles between 2 m and 40 m size in addition many particles may have been part of larger aggregates or clusters that ranged in size from 50 m the majority of individual grains were angular aluminosilicate glass shards with various amounts of smaller adhering particles surface features on individual grains include sulfuric acid droplets and larger 0 5 m to 1 m sulfate gel droplets with various amounts of na mg ca and fe the sulfate gels probably formed by the interaction of sulfur rich gases and solid particles within the cloud soon after eruption ca sulfate laths may have formed by condensation within the plume during eruption or alternatively at a later stage by the reaction of sulfuric acid aerosols with ash fragments within the stratospheric cloud a wilson huang formulation for the settling rate of individual particles qualitatively agrees with the observed particle size distribution for a period at least four months after injection of material into the stratosphere this result emphasizes the importance of particle shape in controlling the settling rate of volcanic ash from the stratosphere

shelf hypoxia in response to global warming after the cretaceous paleogene boundary impact the chicxulub asteroid impact at the cretaceous paleogene k pg boundary resulted in one of the most abrupt global warming events in the past 100 m y presenting an analogue to current global warming here we present high resolution geochemical micropaleontological and palynological records of the brazos 1 texas usa stevns klint denmark and caravaca spain k pg boundary sections to assess the rapid environmental changes during the global warming following the brief k pg boundary impact winter warming during the first millennia after the impact is associated with hypoxic bottom waters at the studied shelf sites as indicated by molybdenum enrichments causing major stress for benthic communities we attribute this decline in dissolved oxygen to a combination of decreased gas solubility and ocean ventilation resulting from the warming of the sea water and increased oxygen demand in shelf bottom waters due to increased nutrient inputs and associated high productivity

fluid mineral reactions and trace metal mobilization in an exhumed natural co2 reservoir green river utah red sandstones near green river utah united states have been bleached by diagenetic fluids field relationships modeling fluid inclusion and isotopic data suggest that the causal fluid was a co2 charged brine distinguishing this site from hydrocarbon related bleaching elsewhere on the colorado plateau mineralogical and chemical profiles from unbleached to bleached sandstone show that bleaching is related to hematite dissolution and precipitation of a 1 2 cm band of secondary oxide and carbonate at the reaction front trace metals are mobilized by the fluid and concentrated near the reaction front high flux fluid pathways are more heavily altered with large scale secondary calcite and iron oxide precipitation changes may be modeled by a reaction with stoichiometry 20fe2o3 5ch4 64co2 19h2o 11h 30fe2 10fehco3 59hco3 the fe rich reduced fluid precipitates iron oxides and carbonate at the reaction front between bleached and unbleached sandstone these findings make the site an analogue for processes occurring over long time scales in geological carbon storage projects trace metals moblized by co2 charged brines are likely to be rapidly re precipitated at reaction fronts

reactivity of micas and cap rock in wet supercritical co2 with so2 and o2 at co2 storage conditions abstract seal or cap rock integrity is a safety issue during geological carbon dioxide capture and storage ccs industrial impurities such as so2 o2 and nox may be present in co2 streams from coal combustion sources so2 and o2 have been shown recently to influence rock reactivity when dissolved in formation water buoyant water saturated supercritical co2 fluid may also come into contact with the base of cap rock after co2 injection supercritical fluid rock reactions have the potential to result in corrosion of reactive minerals in rock with impurity gases additionally present there is the potential for enhanced reactivity but also favourable mineral precipitation the first observation of mineral dissolution and precipitation on phyllosilicates and co2 storage cap rock siliciclastic reservoir core during water saturated supercritical co2 reactions with industrial impurities so2 and o2 at simulated reservoir conditions is presented phyllosilicates biotite phlogopite and muscovite were reacted in contact with a water saturated supercritical co2 containing so2 or so2 and o2 and were also immersed in the gas saturated bulk water secondary precipitated sulfate minerals were formed on mineral surfaces concentrated at sheet edges so2 dissolution and oxidation resulted in solution ph decreasing to 0 74 through sulfuric acid formation phyllosilicate dissolution released elements to solution with 50 fe mobilized geochemical modelling was in good agreement with experimental water chemistry new minerals nontronite smectite hematite jarosite and goethite were saturated in models a cap rock core siltstone sample from the surat basin australia was also reacted in water saturated supercritical co2 containing so2 or in pure supercritical co2 in the presence of so2 siderite and ankerite were corroded and fe chlorite altered by the leaching of mainly fe and al corrosion of micas in the cap rock was however not observed as the ph was buffered by carbonate dissolution ca sulfate and fe bearing precipitates were observed post so2 co2 reaction mainly centered on surface cracks and an illite rich illite smectite precipitate quantified water saturated impure supercritical co2 was observed to have reactivity to rock forming biotite muscovite and phlogopite mineral separates in the cap rock core however carbonates and chlorite were the main reacting minerals showing the importance of assessing actual whole core

latest cretaceous climatic and environmental change in the south atlantic region latest maastrichtian climate change caused by deccan volcanism has been invoked as a cause of mass extinction at the cretaceous paleogene k pg boundary 66 0 ma yet late maastrichtian climate and ecological changes are poorly documented in particular on the southern hemisphere here we present upper maastrichtian lower danian climate and biotic records from the bajada del jaguel bj shelf site neuquen basin argentina employing the tex86 paleothermometer marine palynology dinoflagellate cysts and micropaleontology foraminifera these records are correlated to the astronomically tuned ocean drilling program site 1262 walvis ridge collectively we use these records to assess climatic and ecological effects of deccan volcanism in the southern atlantic region both the tex86 based sea surface temperature sst record at bj and the bulk carbonate 18o based sst record of site 1262 show a latest maastrichtian warming of 2 5 4 c at 450 to 150 kyr before the k pg boundary coinciding with the a large deccan outpouring phase benthic foraminiferal and dinocyst assemblage changes indicate that this warming resulted in enhanced runoff and stratification of the water column likely resulting from more humid climate conditions in the neuquen basin these climate conditions could have been caused by an expanding and strengthening thermal low over the south american continent biotic changes in response to late maastrichtian environmental changes are rather limited when compared to the major turnovers observed at many k pg boundary sites worldwide this suggests that environmental perturbations during the latest maastrichtian warming event were less severe than those following the k pg boundary impact

the pretty hill formation as a natural analogue for co2 storage an investigation of mineralogical and isotopic changes associated with sandstones exposed to low intermediate and high co2 concentrations over geological time abstract the pretty hill formation of the otway basin australia has been studied as a natural analogue for geological storage of anthropogenic co2 in order to examine the effects that co2 concentration and reservoir heterogeneity have on co2 related reactions new petrographic data are presented which validate the use of hylogger as a tool to investigate high resolution vertical changes in reservoir mineralogy the integrated data set confirms earlier interpretations showing that chlorite has been altered to kaolinite and siderite ankerite in reservoir facies exposed to moderate and high co2 concentrations while chlorite remains the dominant clay mineral in all parts of the formation where co2 content is low differences have been observed in the degree of co2 related reaction relative to co2 concentration and reservoir heterogeneity where co2 content is very high c 98 mol and associated with high water saturations both chlorite and detrital feldspars have undergone complete reaction in the reservoir facies resulting in quartzose sandstones with a kaolinite matrix and with siderite as the dominant carbonate precipitate conversely where co2 content is moderate c 29 57 mol and within the gas leg of the reservoir chlorite has undergone significant reaction but much of the original feldspar is preserved suggesting relatively minor reaction carbonate cements from the moderate co2 gas leg comprise calcite siderite and ankerite occurring as cemented zones associated with rock heterogeneities and the present day gas water contact heterogeneities within the gas leg are likely to have associated pore fluid contacts whereby relatively high water saturations will be present in the fine grained baffles and seals the most advanced feldspar reaction occurs locally at the contact between baffles and reservoir rock while reactions have been significantly impeded in the finer grained units due to their low permeabilities stable isotope data presented for carbonate cements analysed from wells with low and moderate co2 levels show no clear distinction relatively early formed calcite has 13c values that require an organic carbon source suggesting precipitation unrelated to the reservoir co2 in the otway basin in contrast diagenetically late calcite and siderite samples display two distinct 13c groups dependent on carbonate type where the calculated fluid carbon isotope compositions are similar to documented magmatic co2 reservoired in the nearby caroline field this suggests that magma derived co2 may have been more prevalent through the pretty hill formation than previously thought although the co2 has not been contained over the long term in the low co2 sites it may have caused the local dissolution of carbonate and laumontite cement and also contributed a source of carbon for late stage calcite cements these studies illustrate the importance of understanding both the reservoir composition and vertical heterogeneity of potential storage systems fluid mineral reactions are likely to be advanced within stacked reservoir facies and impeded within siltstone layers while the distribution of carbonate cement may increase the reservoir heterogeneity by the formation of cemented siltstone sandstone layers thereby creating impermeable barriers or baffles to co2

long term reactivity of co2 in a low salinity reservoir seal complex abstract an understanding of the long term reactivity of different rock types to injected co2 is needed for sequestration site assessment relative to saline aquifer studies the long term reactivity of co2 in low salinity aquifers has received little attention currently in australia the surat basin is being appraised for its large scale co2 storage potential within low salinity aquifers sixteen core samples from the precipice sandstone and evergreen formation the notional target reservoir and seal complex were characterized for mineral content helium mercury injection and micro ct porosities air permeability and imaged with sem eds samples consisted of quartz rich reservoir sandstones feldspar and clay rich or calcite cemented sandstones secondary reservoir mudstones sealing complex and oolitic ironstones sealing complex derived from braided river fluvial deltaic and restricted marine shoal depositional environments respectively the reservoir sandstone samples characterized here had measured total porosity that ranged from 11 to 23 with pore throats mainly between 90 and 100 m and core air permeability from 558 to 3397 md in the precipice sandstone reservoir sample ct plugs 98 of the pore space was connected with calculated vertical permeability 145 4611 md and horizontal 4291 8200 md feldspar and clay rich sandstone and mudstone samples from the overlying evergreen formation had porosity that ranged between 0 2 and 22 9 with a wide range of pore throat sizes from 0 005 to 30 m and permeability from 0 2 to 28 1 md respectively ironstone and mudstone samples from the westgrove ironstone member evergreen formation had porosity from 0 7 to 9 7 and a low permeability of 0 04 md kinetic geochemical co2 reactivity models made predictions over two time scales 30 or 1000 years selected models also accounted for the potential presence of 10 ppm so2 gas the precipice sandstone quartz rich reservoir sandstones had consistently small amounts of reactive minerals and mineral trapping or scaling of the reservoir was not predicted over 30 years with the ph approximately 4 5 after 30 years samples from the evergreen formation included feldspar and clay rich sandstones and mudstones several contained variable amounts of carbonate cement their response to co2 was more influenced by mineral content than rock type plagioclase feldspars and fe rich chlorite were the main silicate minerals that reacted to produce siderite and ankerite mineral trapping up to 2 57 kg m3 co2 in the very unlikely event that co2 rich fluids migrated upwards as far as the westgrove ironstone member chlorite is predicted to alter to siderite this study indicates that the precipice sandstone reservoir in the study region has a low likelihood of mineral scaling which is favorable to avoid co2 injectivity issues mineral trapping as ankerite and siderite could be expected to trap co2 in the chlorite and plagioclase rich evergreen formation seal lithologies further work is suggested on validating long term predictions with observation data from natural analogue studies

postimpact earliest paleogene warming shown by fish debris oxygen isotopes el kef tunisia greenhouse warming is a predicted consequence of the chicxulub impact but supporting data are sparse this shortcoming compromises understanding of the impact s effects and it has persisted due to an absence of sections that both contain suitable material for traditional carbonate or organic based paleothermometry and are complete and expanded enough to resolve changes on short time scales we address the problem by analyzing the oxygen isotopic composition of fish debris phosphatic microfossils that are relatively resistant to diagenetic alteration from the global stratotype section and point for the cretaceous paleogene boundary at el kef tunisia we report an 1 per mil decrease in oxygen isotopic values 5 c warming beginning at the boundary and spanning 300 centimeters of section 100 000 years the pattern found matches expectations for impact initiated greenhouse warming

the chemical dissolution and physical migration of minerals induced during co2 laboratory experiments their relevance for reservoir quality the characterization of the quality and storage capacity of geological underground reservoirs is one of the most important and challenging tasks for the realization of carbon capture and storage ccs projects one approach for such an evaluation is the upscaling of data sets achieved by laboratory co2 batch experiments to field scale sub microscopic petrophysical tomographic and chemical analytical methods were applied to reservoir sandstone samples from the altmark gas field before and after static autoclave batch experiments at reservoir specific conditions to study the relevance of injected co2 on reservoir quality these investigations confirmed that the chemical dissolution of pore filling mineral phases carbonate anhydrite associated with an increased exposure of clay mineral surfaces and the physical detachment and mobilization of such clay fines illite chlorite are most appropriate to modify the quality of storage sites thereby the complex interplay of both processes will affect the porosity and permeability in opposite ways mineral dissolution will enhance the rock porosity and permeability but fine migration can deteriorate the permeability these reactions are realized down to m scale and will affect the fluid rock reactivity of the reservoirs their injectivity and recovery rates during co2 storage operations

deccan volcanism caused coupled pco2 and terrestrial temperature rises and pre impact extinctions in northern china evaluating the terrestrial climate record provides a critical test of the roles of chicxulub impact and deccan traps volcanism during the cretaceous paleogene k pg mass extinction most evidence came from marine records but our new clumped isotopes data from paleosol carbonates in the songliao basin provide a terrestrial climate history from northern china this reveals there was a pre impact warming caused by the onset of deccan traps volcanism whereas the following short term cooling then another warming episode were likely caused by chicxulub impact and post boundary volcanism our study suggests that the pco levels were probably the main control on the latest cretaceous cooling and the climatic fluctuations across the k pg boundary interval in northern china in the songliao basin the pre impact deccan traps volcanism links to losses of half of the lacustrine algae species charophytes and almost all of the lacustrine ostracodes this suggests that the deccan traps volcanism had already destabilized the ecosystem and caused extinctions prior to the chicxulub impact

the impact of composition on pore throat size and permeability in high maturity shales middle and upper devonian horn river group northeastern british columbia canada abstract shale reservoirs of the middle and upper devonian horn river group provide an opportunity to study the influence of rock composition on permeability and pore throat size distribution in high maturity formations sedimentological geochemical and petrophysical analyses reveal relationships between rock composition pore throat size and matrix permeability in our sample set measured matrix permeability ranges between 1 69 and 42 81 nanodarcies and increases with increasing porosity total organic carbon toc content positively correlates to permeability and exerts a stronger control on permeability than inorganic composition a positive correlation between silica content and permeability and abundant interparticle pores between quartz crystals suggests that quartz may be another factor enhancing the permeability pore throat size distributions are strongly related to toc content in organic rich samples the dominant pore throat size is less than 10 nm whereas in organic lean samples pore throat size distribution is dominantly greater than 20 nm sem images suggest that in organic rich samples organic matter pores are the dominant pore type whereas in quartz rich samples the dominant type is interparticle pores between quartz grains in clay rich and carbonate rich samples the dominant pore type is intraparticle pores which are fewer and smaller in size high permeability shales are associated with specific depositional facies massive and pyritic mudstones rich in toc and quartz have comparatively high permeability laminated mudstone bioturbated mudstone and carbonate facies which are relatively enriched in clay or carbonate have fairly low permeability

geochemical effects of an oxycombustion stream containing so2 and o2 on carbonate rocks in the context of co2 storage this paper describes the effects of the injection of a co2 dominated gas mixture into a geologic reservoir rock through experimental work in the context of limiting greenhouse gas emissions into the atmosphere the injected gas mixture consists of the exhaust fumes from an oxyboiler without desulphurisation with the following mole fraction composition co2 0 82 so2 0 04 o 2 0 04 n 2 0 04 and ar 0 06 corresponding experiments using pure co2 and n 2 were performed as a benchmark the rock sample was obtained by drilling to a depth of 4600 m into a low porosity dolostone reservoir containing micrometric to centimetric fractures in the south west of france northern pyrenees the fracture network represents the primary volume available for co2 storage and is partly filled with dolomite separated from the rock matrix by a thin layer of calcite covering the wall rocks experimental reactivity of the rock was tested in 2 cm 3 batch reactors in the presence of saline water 25 g l nacl and a gas phase pure n 2 pure co2 and gas mixture chemical analyses of the reacting solutions indicated that the mineralogic assemblage during exposure to pure co2 was in equilibrium with the aqueous solution raman analyses of the gas phase revealed only the presence of co2 optical and electronic microscopy of the resultant solid phases indicated partial dissolution of carbonates and oxidation of the pyrite surfaces in the presence of the gas mixture important mineralogic alteration occurred together with the consumption of half of the o 2 and total consumption of the so2 this high reactivity with the gas mixture leads to the complete dissolution of calcite and partial dissolution of dolomite and the precipitation of anhydrite and barite particularly in the zones where the calcite was initially present similarly pyrite was completely oxidised to hematite analyses of the rock samples indicated partial alteration of the clay minerals in the matrix to potassic beidellite in the experiment involving pure co2 and solely to vermiculites in the gas mixture experiment in conclusion the presence of so2 in the injection stream associated with the presence of o 2 results in an early strong acidification of the water which was buffered by the significant reactivity of the carbonates dissolution of all of the calcite and 6 of the dolomite and partial alteration of the clay minerals 87 of illite and 100 of smectite to vermiculites pyrite and aqueous fe from clays were completely oxidised by o 2 resulting in hematite and fe3 the mineralogic alteration and consequent volume changes under experimental conditions led to a slight increase in the porosity of the dolomite matrix and an average pore volume loss of 11 in the fractures caused by the replacement of calcite with anhydrite due to its high reactivity with carbonate so2 can react early during the injection phase the spatial distribution of calcite in the fractures of the reservoir has to be considered as one of the primary parameters controlling the evolution of the reservoir in terms of injectivity and petrophysical properties particularly in the zone near the injection wellbores the integrity of the calcite rich caprock is however ensured due to its thickness more than 1000 m and its calcite content which leads to ph buffering and anhydrite precipitation which in turn induces a porosity reduction and a possible coating of the rock formation

gas water rock interactions in frio formation following co2 injection implications for the storage of greenhouse gases in sedimentary basins to investigate the potential for the geologic storage of co2 in saline sedimentary aquifers 1600 t of co2 were injected at 1500 m depth into a 24 m thick sandstone section of the frio formation a regional brine and oil reservoir in the u s gulf coast fluid samples obtained from the injection and observation wells before co2 injection showed a na cacl type brine with 93 000 mg l total dissolved solids tds at near saturation with ch4 at reservoir conditions following co2 breakthrough samples showed sharp drops in ph 6 5 5 7 pronounced increases in alkalinity 100 3000 mg l as hco3 and fe 30 1100 mg l and significant shifts in the isotopic compositions of h2o dissolved inorganic carbon dic and ch4 geochemical modeling indicates that brine ph would have dropped lower but for the buffering by dissolution of carbonate and iron oxyhydroxides this rapid dissolution of carbonate and other minerals could ultimately create pathways in the rock seals or well cements for co2 and brine leakage dissolution of minerals especially iron oxyhydroxides could mobilize toxic trace metals and where residual oil or suitable organics are present the injected co2 could also mobilize toxic organic compounds environmental impacts could be major if large brine volumes with mobilized toxic metals and organics migrated into potable groundwater the d 18 o values for brine and co2 samples indicate that supercritical co2 comprises 50 of pore fluid volume 6 mo after the end of injection postinjection sampling coupled with geochemical modeling indicates that the brine gradually will return to its preinjection composition

a high resolution marine 187os 188os record for the late maastrichtian distinguishing the chemical fingerprints of deccan volcanism and the kp impact event abstract a composite late maastrichtian 65 5 to 68 5 ma marine osmium os isotope record based on samples from the southern ocean odp site 690 the tropical pacific ocean dsdp site 577 the south atlantic dsdp site 525 and the paleo tethys ocean demonstrates that subaerially exposed pelagic carbonates can record seawater os isotope variations with a fidelity comparable to sediments recovered from the seafloor new results provide robust evidence of a 20 decline in seawater 187os 188os over a period of about 200 kyr early in magnetochron c29r well below the cretaceous paleogene boundary kpb confirming previously reported low resolution data from the south atlantic ocean new results also confirm a second more rapid decline in 187os 188os associated with the kpb that is accompanied by a significant increase in os concentrations complementary platinum pt and iridium ir concentration data indicate that the length scale of diagenetic remobilization of platinum group elements from the kpb is less than 1 m and does not obscure the pre kpb decline in 187os 188os increases in bulk sediment ir concentrations and decreases in bulk carbonate content that coincide with the os isotope shift suggest that carbonate burial flux may have been lower during the initial decline in 187os 188os we speculate that diminished carbonate burial rate may have been the result of ocean acidification caused by deccan volcanism

distributional variations in marine crenarchaeotal membrane lipids a new tool for reconstructing ancient sea water temperatures it has recently been shown that membrane lipids of marine crenarchaeota a ubiquitous and abundant component of plankton occur in relatively high concentrations in recent and ancient sediments in this study we investigated the environmental controls on the relative distribution of these lipids in surface sediments we especially focussed on temperature as it is known from the thermophilic genetic relatives of marine crenarchaetoa that the composition of their membrane strongly depends on growth temperature indeed a significant linear correlation r2 0 92 is found between the number of cyclopentane rings in sedimentary membrane lipids derived from marine crenarchaeota and the annual mean sea surface temperatures this suggests that the mechanism of physical adaptation of their membrane compositions to temperature is identical to that of their thermophilic relatives in turn archaeal lipid distributions in sediments may thus allow the reconstruction of sea water temperatures of ancient marine environments

on the interaction of pure and impure supercritical co2 with rock forming minerals in saline aquifers an experimental geochemical approach abstract the aim of this experimental study was to evaluate and compare the geochemical impact of pure and impure co2 on rock forming minerals of possible co2 storage reservoirs this geochemical approach takes into account the incomplete purification of industrial captured co2 and the related effects during injection and provides relevant data for long term storage simulations of this specific greenhouse gas batch experiments were conducted to investigate the interactions of supercritical co2 brine and rock forming mineral concentrates albite microcline kaolinite biotite muscovite calcite dolomite and anhydrite using a newly developed experimental setup after up to 42 day 1000 h experiments using pure and impure supercritical co2 the dissolution and solution characteristics were examined by xrd xrf sem and eds for the solid and icp ms and ic for the fluid reactants respectively experiments with mixtures of supercritical co2 99 5 vol and so2 or no2 impurities 0 5 vol suggest the formation of h2so4 and hno3 reflected in ph values between 1 and 4 for experiments with silicates and anhydrite and between 5 and 6 for experiments with carbonates these acids should be responsible for the general larger amount of cations dissolved from the mineral phases compared to experiments using pure co2 for pure co2 a ph of around 4 was obtained using silicates and anhydrite and 7 8 for carbonates dissolution of carbonates was observed after both pure and impure co2 experiments anhydrite was corroded by approximately 50 wt and gypsum precipitated during experiments with supercritical co2 no2 silicates do not exhibit visible alterations during all experiments but released an increasing amount of cations in the reaction fluid during experiments with impure co2 nonetheless precipitated secondary carbonates could not be identified

planimetric and volumetric glacier changes in the khumbu himal nepal since 1962 using corona landsat tm and aster data multitemporal space imagery from 1962 corona kh 4 1992 landsat tm 2001 and 2005 terra aster was used to investigate the glacier changes in the khumbu himal nepal the ice coverage in the investigation area decreased by about 5 between 1962 and 2005 with the highest retreat rates occurring between 1992 and 2001 the debris coverage increased concomitantly with the decrease in total glacier area the clean ice area decreased by 10 digital terrain model dtm generation from the early corona kh 4 stereo data in this high relief terrain is time consuming and the results still contain some elevation errors however these are minor in the snow free areas with gentle slopes thus comparison of the surfaces of the debris covered glacier tongues based on the corona dtm and an aster dtm is feasible and shows the downwasting of the debris covered glaciers the highest downwasting rates more than 20 m 0 5 m a 1 can be found near the transition zone between the active and the stagnant glacier parts of the debris covered glacier tongues the downwasting is lower but still evident in the active ice areas and at the snout with thick debris cover all investigated debris covered glaciers in the study area show similar behaviour the estimated volume loss for the investigated debris covered glacier tongues is 0 19 km 3

limited global change due to the largest known quaternary eruption toba 74 kyr bp abstract the 74 kyr bp super eruption of toba volcano in sumatra is the largest known quaternary eruption on the basis of preserved deposits the eruption magnitude has been estimated at 7 10 15 kg 2800 km 3 of dense magma the largest sulphate anomaly in the greenland ice sheet project 2 core has been identified as fallout from toba s stratospheric aerosol veil correlation of the sulphate and oxygen isotope stratigraphy of the ice core suggests that the toba eruption might have played a role in triggering a millennium of cool climate prior to dansgaard oeschger event 19 although a comparable stadial preceded event 20 a possible 6 yr duration volcanic winter immediately following the eruption has also been proposed as the cause of a putative bottleneck in human population supporting in a general way the garden of eden model for the origin of modern humans however along with counter arguments regarding the timing of any demographic crash there remain major gaps in our understanding of the 74 kyr bp toba eruption that hinder attempts to model its global atmospheric and climatic and hence human consequences the tephra record reveals basic aspects of the eruption style but calculations of the duration and hence intensity and plume height of the event are poorly constrained furthermore estimates of the sulphur yield of the erupting magma central to predictions of its atmospheric and climatic impacts vary by two orders of magnitude 3 5 330 10 10 kg previous estimates of globally averaged surface cooling of 3 5 c after the eruption are probably too high a figure closer to 1 c appears more realistic the volcanological uncertainties need to be appreciated before accepting arguments for catastrophic consequences of the toba super eruption

energy volatile production and climatic effects of the chicxulub cretaceous tertiary impact a comprehensive analysis of volatiles in the chicxulub impact strongly supports the hypothesis that impact generated sulfate aerosols caused over a decade of global cooling acid rain and disruption of ocean circulation which contributed to the mass extinction at the cretaceous tertiary k t boundary the crater size meteoritic content of the k t boundary clay and impact models indicate that the chicxulub crater was formed by a short period comet or an asteroid impact that released 0 7 3 4 x 10 31 ergs of energy impact models and experiments combined with estimates of volatiles in the projectile and target rocks predict that over 200 gigatons gt each of so2 and water vapor and over 500 gt of co2 were globally distributed in the stratosphere by the impact additional volatiles may have been produced on a global or regional scale that formed sulfate aerosols rapidly in cooler parts of the vapor plume causing an early intense pulse of sulfuric acid rain estimates of the conversion rate of stratospheric so2 and water vapor to sulfate aerosol based on volcanic production of sulfate aerosols coupled with calculations of diffusion coagulation and sedimentation demonstrate that the 200 gt stratospheric so2 and water vapor reservoir would produce sulfate aerosols for 12 years these sulfate aerosols caused a second pulse of acid rain that was global radiative transfer modeling of the aerosol clouds demonstrates 1 that if the initial rapid pulse of sulfate aerosols was global photosynthesis may have been shut down for 6 months and 2 that for the second prolonged aerosol cloud solar transmission dropped 80 by the end of first year and remained 50 below normal for 9 years as a result global average surface temperatures probably dropped between 5 degrees and 31 degrees k suggesting that global near freezing conditions may have been reached impact generated co2 caused less than 1 degree k greenhouse warming and therefore was insignificant compare to the sulfate cooling the magnitude of sulfate cooling depends largely upon the rate of ocean mixing as surface waters cool sink and are replaced by upwelling of deep ocean water this upwelling apparently drastically altered ocean stratification and circulation which may explain the global collapse of the delta 13c gradient between surface and deep ocean waters at the k t boundary

recent contributions of glaciers and ice caps to sea level rise satellite measurements of earth s gravity field show that the mass loss of glaciers and ice caps contributed to sea level rise by approximately 0 4 millimetres per year between 2003 and 2010 the extent to which mass loss from ice covered land areas contributes to sea level rise is not known accurately in part because previous global estimates use different techniques for glaciers ice caps and ice sheets the gravity recovery and climate experiment grace satellite has provided monthly measurements of the global gravity field since 2002 using grace data jacob et al assess regional mass loss between 2003 and 2010 and conclude that mass loss from ice covered land areas contributed almost 1 5 mm per year to the sea level rise estimated mass loss from the high mountains of asia was negligible in contrast to some other reports glaciers and ice caps gics are important contributors to present day global mean sea level rise1 2 3 4 most previous global mass balance estimates for gics rely on extrapolation of sparse mass balance measurements1 2 4 representing only a small fraction of the gic area leaving their overall contribution to sea level rise unclear here we show that gics excluding the greenland and antarctic peripheral gics lost mass at a rate of 148 30 gt yr 1 from january 2003 to december 2010 contributing 0 41 0 08 mm yr 1 to sea level rise our results are based on a global simultaneous inversion of monthly grace derived satellite gravity fields from which we calculate the mass change over all ice covered regions greater in area than 100 km2 the gic rate for 2003 2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2 the high mountains of asia in particular show a mass loss of only 4 20 gt yr 1 for 2003 2010 compared with 47 55 gt yr 1 in previously published estimates2 5 for completeness we also estimate that the greenland and antarctic ice sheets including their peripheral gics contributed 1 06 0 19 mm yr 1 to sea level rise over the same time period the total contribution to sea level rise from all ice covered regions is thus 1 48 0 26 mm 1 which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6

supercritical carbon dioxide and sulfur in the madison limestone a natural analog in southwest wyoming for geologic carbon sulfur co sequestration article i nfo the madison limestone on the moxa arch southwest wyoming usa contains large volumes 65 95 of supercritical co2 that it has stored naturally for 50 million years this reservoir also contains supercritical h2s aqueous sulfur complexes so4 2 and hs and sulfur bearing minerals anhydrite and pyrite although so2 is not present these sulfur bearing phases are known products of so2 disproportionation in other water rock systems the natural co occurrence of so4 2 s 2 supercritical co2 and brine affords the opportunity to evaluate the fate of a carbon sulfur co sequestration scenario mineralogic data was obtained from drill core and aqueous geochemical data from wells outside and within the current supercritical co2 sulfur brine rock system in addition to dolomite calcite and accessory sulfur bearing minerals the madison limestone contains accessory quartz and the aluminum bearing minerals feldspar illite and analcime dawsonite naalco3 oh 2 predicted as an important carbon sink in sequestration modeling studies is not present after confirming equilibrium conditions for the madison limestone system reaction path models were constructed with initial conditions based on data from outside the reservoir addition of supercritical co2 to the madison limestone was simulated and the results compared to data from inside the reservoir the model accurately predicts the observed mineralogy and captures the fundamental changes expected in a madison limestone brine system into which co2 is added ph decreases from 5 7 to 4 5 at 90 c and to 4 0 at 110 c as expected from dissolution of supercritical co2 creation of carbonic acid and buffering by the carbonate rock the calculated redox potential increases by 0 1 v at 90 c and 0 15 v at 110 c due to equilibrium among co2 anhydrite and pyrite final calculated eh and ph match conditions for the co existing sulfur phases present in produced waters and core from within the reservoir total dissolved solids increase with reaction progress mostly due to dissolution of calcite with an accompanying increase in dissolved bicarbonate the madison limestone is a natural example of the thermodynamic end point that similar fluid rock systems will develop following emplacement of a supercritical co2 sulfur mixture and is a natural analog for geologic carbon sulfur co sequestration

chemical effects of sulfur dioxide co injection with carbon dioxide on the reservoir and caprock mineralogy and permeability in depleted gas fields the most suitable candidates for subsurface storage of co2 are depleted gas fields their ability to retain co2 can however be influenced by the effect which impurities in the co2 stream e g h2s and so2 have on the mineralogy of reservoir and seal in order to investigate the effects of so2 we carried out laboratory experiments on reservoir and cap rock core samples from gas fields in the northeast of the netherlands the rock samples were contained in reactor vessels for 30 days in contact with co2 and 100 ppm so2 under in situ conditions 300 bar 100 degrees c the vessels also contained brine with the same composition as in the actual reservoir furthermore equilibrium modeling was carried out using phreeqc software in order to model the experiments on caprock samples after the experiments the permeability of the reservoir samples had increased by a factor of 1 2 2 2 as a result of dissolution of primary reservoir minerals analysis of the associated brine samples before and after the experiments showed that concentrations of k si and al had increased indicative of silicate mineral dissolution in the caprock samples composed of carbonate and anhydrite minerals permeability changed by a factor of 0 79 23 the increase in permeability is proportional to the amount of carbonate in the caprock with higher carbonate content in comparison with anhydrite the permeability increase is higher due to the additional carbonate dissolution this dependency of permeability variations was verified by the modeling study hence caprock with a higher anhydrite content in comparison with carbonate minerals has a lower risk of leakage after co injection of 100 ppmv so2 with co2 c 2015 elsevier ltd all rights reserved

a fresh approach to investigating co2 storage experimental co2 water rock interactions in a low salinity reservoir system the interactions between co2 water and rock in low salinity host formations remain largely unexplored for conditions relevant to co2 injection and storage core samples and sub plugs from five jurassic aged surat basin sandstones and siltstones of varying mineralogy have been experimentally reacted in low salinity water with supercritical co2 at simulated in situ reservoir conditions p 12mpa and t 60 c for 16days 384h with a view to characterising potential co2 water rock interactions in fresh or low salinity potential siliclastic co2 storage targets located in queensland australia co2 water rock reactions were coupled with detailed mineral and porosity characterisation obtained prior to and following reaction to identify changes in the mineralogy and porosity of selected reservoir and seal rocks during simulated co2 injection aqueous element concentrations were measured from fluid extracts obtained periodically throughout the experiments to infer fluid rock reactions over time fluid analyses show an evolution of dissolved concentration over time with most major e g ca fe si mg mn and minor e g s sr ba zn components increasing in concentration during reaction with co2 similar trends between elements reflect shared sources and or similar release mechanisms such as dissolution and desorption with decreasing ph small decreases in concentration of selected elements were observed towards the end of some experiments however no precipitation of minerals was directly observed in petrography sample characterisation on a fine scale allowed direct scrutiny of mineralogical and porosity changes by comparing pre and post reaction observations scanning electron microscopy and registered 3d images from micro computed tomography micro ct indicate dissolution of minerals including carbonates chlorite biotite members and to a lesser extent feldspars quantitative mineral mapping of sub plugs identified dissolution of calcite from carbonate cemented core with a decrease in calcite content from 17vol to 15vol following reaction and a subsequent increase in porosity of 1 1vol kinetic geochemical modelling of the co2 water rock experiments successfully reproduced the general trends observed in aqueous geochemistry for the investigated major elements after coupling experimental geochemistry with detailed sample characterisation and numerical modelling expected initial reactions in the near well region include partial dissolution and desorption of calcite mixed carbonates chloritic clays and annite due to ph decrease followed in the longer term by dissolution of additional silicates such as feldspars dissolution of carbonates is predicted to improve injectivity in the near well environment and contribute to the eventual re precipitation of carbonates in the far field

the chicxulub impact event and its environmental consequences at the cretaceous tertiary boundary abstract an impact mass extinction hypothesis for the cretaceous tertiary k t boundary transition has been confirmed with multiple lines of evidence beginning with the discovery of impact derived ir in k t boundary sediments and culminating in the discovery of the chicxulub impact crater likewise a link between the chicxulub impact crater and k t boundary sediments has been confirmed with multiple lines of evidence including stratigraphic petrological geochemical and isotopic data the environmental effects of the chicxulub impact event were global in their extent largely because of the interaction of ejected impact debris with the atmosphere the environmental consequences of the chicxulub impact event and their association with the k t boundary mass extinction event indicate that impact cratering processes can affect both the geologic and biologic evolution of our planet