monitoring gas and heat emissions at norris geyser basin yellowstone national park usa based on a combined eddy covariance and multi gas approach abstract we quantified gas and heat emissions in an acid sulfate vapor dominated area 0 04 km2 of norris geyser basin located just north of the 0 63 ma yellowstone caldera and near an area of anomalous uplift from 14 may to 3 october 2016 an eddy covariance system measured half hourly co2 h2o and sensible h and latent le heat fluxes and a multi gas instrument measured 1 hz frequency atmospheric h2o co2 and h2s volumetric mixing ratios we also measured soil co2 fluxes using the accumulation chamber method and temperature profiles on a grid and collected fumarole gas samples for geochemical analysis eddy covariance co2 fluxes ranged from 56 to 885 g m 2 d 1 using wavelet analysis average daily eddy covariance co2 fluxes were locally correlated with average daily environmental parameters on several day to monthly time scales estimates of co2 emission rate from the study area ranged from 8 6 t d 1 based on eddy covariance measurements to 9 8 t d 1 based on accumulation chamber measurements eddy covariance water vapor fluxes ranged from 1178 to 24 600 g m 2 d 1 nighttime h and le were considered representative of hydrothermal heat fluxes and ranged from 4 to 183 and 38 to 504 w m 2 respectively the total hydrothermal heat emission rate h le radiant estimated for the study area was 11 6 mw and le contributed 69 of the output the mean standard deviation of h2o co2 and h2s mixing ratios measured by the multi gas system were 9 3 3 1 parts per thousand 467 61 ppmv and 0 5 0 6 ppmv respectively and variations in the gas compositions were strongly correlated with diurnal variations in environmental parameters wind speed and direction atmospheric temperature after removing ambient h2o and co2 the observed variations in the multi gas data could be explained by the mixing of relatively h2o co2 h2s rich fumarole gases with co2 rich and h2o h2s poor soil gases the fumarole h2o co2 and co2 h2s end member ratios 101 7 and 27 1 respectively on average were invariant during the measurement period and fell within the range of values measured in direct fumarole gas samples the soil gas h2o co2 end member ratios 15 30 were variable and low relative to the fumarole end member likely resulting from water vapor loss during cooling and condensation in the shallow subsurface whereas the co2 h2s end member ratio was high 160 presumably related to transport of co2 dominated soil gas emissions mixed with trace fumarolic emissions to the multi gas station nighttime eddy covariance ratios of h2o to co2 flux were typically between the soil gas and fumarole end member h2o co2 ratios defined by multi gas measurements overall the combined eddy covariance and multi gas approach provides a powerful tool for quasi continuous measurements of gas and heat emissions for improved volcano hydrothermal monitoring

solute and geothermal flux monitoring using electrical conductivity in the madison firehole and gibbon rivers yellowstone national park abstract the thermal output from the yellowstone magma chamber can be estimated from the cl flux in the major rivers in yellowstone national park and by utilizing continuous discharge and electrical conductivity measurements the cl flux can be calculated the relationship between electrical conductivity and concentrations of cl and other geothermal solutes na so 4 f hco 3 sio 2 k li b and as was quantified at monitoring sites along the madison gibbon and firehole rivers which receive discharge from some of the largest and most active geothermal areas in yellowstone except for some trace elements most solutes behave conservatively and the ratios between geothermal solute concentrations are constant in the madison gibbon and firehole rivers hence dissolved concentrations of cl na so 4 f hco 3 sio 2 k li ca b and as correlate well with conductivity r 2 0 9 for most solutes and most exhibit linear trends the 2011 flux for cl so 4 f and hco 3 determined using automated conductivity sensors and discharge data from nearby usgs gaging stations is in good agreement with those of previous years 1983 1994 and 1997 2008 at each of the monitoring sites continuous conductivity monitoring provides a cost and labor effective alternative to existing protocols whereby flux is estimated through manual collection of numerous water samples and subsequent chemical analysis electrical conductivity data also yield insights into a variety of topics of research interest at yellowstone and elsewhere 1 geyser eruptions are easily identified and the solute flux quantified with conductivity data 2 short term heavy rain events can produce conductivity anomalies due to dissolution of efflorescent salts that are temporarily trapped in and around geyser basins during low flow periods during a major rain event in october 2010 180 000 kg of additional solute was measured in the madison river 3 the output of thermal water from the gibbon river appears to have increased by about 0 2 a in recent years while the output of thermal water for the firehole river shows a decrease of about 10 from 1983 to 2011 confirmation of these trends will require continuing cl flux monitoring over the coming decades

naturally acidic surface and ground waters draining porphyry related mineralized areas of the southern rocky mountains colorado and new mexico abstract acidic metal rich waters produced by the oxidative weathering and resulting leaching of major and trace elements from pyritic rocks can adversely affect water quality in receiving streams and riparian ecosystems five study areas in the southern rocky mountains with naturally acidic waters associated with porphyry mineralization were studied to document variations in water chemistry and processes that control the chemical variations study areas include the upper animas river watershed east alpine gulch mount emmons and handcart gulch in colorado and the red river in new mexico although host rock lithologies in all these areas range from precambrian gneisses to cretaceous sedimentary units to tertiary volcanic complexes the mineralization is tertiary in age and associated with intermediate to felsic composition porphyritic plutons pyrite is ubiquitous ranging from 1 to 5 vol springs and headwater streams have ph values as low as 2 6 so4 up to 3700 mg l and high dissolved metal concentrations for example fe up to 400 mg l cu up to 3 5 mg l and zn up to 14 4 mg l intensity of hydrothermal alteration and presence of sulfides are the primary controls of water chemistry of these naturally acidic waters subbasins underlain by intensely hydrothermally altered lithologies are poorly vegetated and quite susceptible to storm induced surface runoff within the red river study area results from a storm runoff study documented downstream changes in river chemistry ph decreased from 7 80 to 4 83 alkalinity decreased from 49 4 to

evidence for a new shallow magma intrusion at la soufriere of guadeloupe lesser antilles insights from long term geochemical monitoring of halogen rich hydrothermal fluids more than three decades of geochemical monitoring of hot springs and fumaroles of la soufriere of guadeloupe allows the construction of a working model of the shallow hydrothermal system this system is delimited by the nested caldera structures inherited from the repeated flank collapse events and the present dome built during the last magmatic eruption 1530 ad and which has been highly fractured by the subsequent phreatic or phreatomagmatic eruptions because it is confined into the low volume highly compartmented and partially sealed upper edifice structure the hydrothermal system is highly reactive to perturbations in the volcanic activity input of deep magmatic fluids the edifice structure sealing and fracturing and meteorology wet tropical regime the current unrest which began with a mild reactivation of fumarolic activity in 1990 increased markedly in 1992 with seismic swarms and an increase of degassing from the summit of the dome in 1997 seismic activity increased further and was accompanied by a sudden high flux hcl rich gas from summit fumaroles we focus on the interpretation of the time series of the chemistry and temperature of fumarolic gases and hot springs as well as the relative behaviours of halogens f cl br and i this extensive geochemical time series shows that the deep magmatic fluids have undergone large changes in composition due to condensation and chemical interaction with shallow groundwater scrubbing it is possible to trace back these processes and the potential contribution of a deep magmatic source using a limited set of geochemical time series t co2 and total s content in fumaroles t and cl in hot springs and the relative fractionations between f cl br and i in both fluids coupling 35 years of geochemical data with meteorological rainfall data and models of ion transport in the hydrothermal aquifers has allowed us to identify a series of magmatic gas pulses into the hydrothermal system since the 1976 1977 crisis the contrasting behaviours of s and cl bearing species in fumarolic gas and in thermal springs suggests that the current activity is the result of a new magma intrusion which was progressively emplaced at shallow depth since 1992 although it might still be evolving the characteristics of this new intrusion indicate that it hasalready reached a magnitude similar to the intrusion that was emplaced during the 1976 1977 eruptive crisis the assessment of potential hazards associated with evolution of the current unrest must consider the implications of recurrent intrusion and further pressurization of the hydrothermal system on the likelihood of renewed phreatic explosive activity moreover the role of hydrothermal pressurization on the basal friction along low strength layers within the upper part of the edifice must be evaluated with regards to partial flank collapse at this stage enhanced monitoring research and data analysis is required to quantify the uncertainties related to future scenarios of renewed eruptive activity and magmatic evolution

diel behavior of rare earth elements in a mountain stream with acidic to neutral ph abstract diel 24 h changes in concentrations of rare earth elements ree were investigated in fisher creek a mountain stream in montana that receives acid mine drainage in its headwaters three simultaneous 24 h samplings were conducted at an upstream station ph 3 3 an intermediate station ph 5 5 and a downstream station ph 6 8 the ree were found to behave conservatively at the two upstream stations at the downstream station ree partitioned into suspended particles to a degree that varied with the time of day and concentrations of dissolved ree were 2 9 to 9 4 fold 190 to 830 higher in the early morning vs the late afternoon the decrease in dissolved ree concentrations during the day coincided with a corresponding increase in the concentration of ree in suspended particles such that diel changes in the total ree concentrations were relatively minor 27 to 55 increase at night across the lanthanide series the heavy ree partitioned into the suspended solid phase to a greater extent than the light ree filtered samples from the downstream station showed a decrease in shale normalized ree concentration across the lanthanide series with positive anomalies at la and gd and a negative eu anomaly as the temperature of the creek increased in the afternoon the slope of the ree profile steepened and the magnitude of the anomalies increased the above observations are explained by cyclic adsorption of ree onto suspended particles of hydrous ferric and aluminum oxides hfo hao conditional partition coefficients for each ree between the suspended solids and the aqueous phase reached a maximum at 1700 hours and a minimum at 0700 hours this pattern is attributed to diel variations in stream temperature possibly reinforced by kinetic factors i e slower rates of reaction at night than during the day estimates of the enthalpy of adsorption of each ree onto suspended particles based on the field results averaged 82 kj mol and are similar in magnitude to estimates in the literature for adsorption of divalent metal cations onto clays and hydrous metal oxides the results of this study have important implications to the use of ree as hydrogeochemical tracers in streams

solidification history of the kitdlit lens immiscible metal and sulphide liquids from a basaltic dyke on disko central west greenland

organic matter size fraction relationships for recent sediments from the orinoco delta venezuela abstract fifteen recent sediment samples from the offshore orinoco delta venezuela were separated by sieving and pipette analysis into seven size fractions ranging from 4o to 10o in 1 o units total organic carbon was determined for each size fraction and the organic matter characterized by pyrolysis and pyrolysis gas chromatography the sediments average 0 98 organic matter with somewhat higher values nearshore nearshore sediments also had higher organic contents in the coarsest fractions and a decrease in organic matter from coarse to fine sediment fractions sediments from further offshore generally show the highest organic contents in the finer fractions pyrolysis showed a low bitumen content and confirmed that the kerogen was dominantly terrestrial and gas prone the observed trends were attributed to sorting of organic matter by its physical characteristics with the denser coarse grained material settling out nearshore and the finer grained material being carried further from shore and settling out with finer grained sediments

eruptions at lone star geyser yellowstone national park usa 1 energetics and eruption dynamics 1 geysers provide a natural laboratory to study multiphase eruptive processes we present results from a 4 day experiment at lone star geyser in yellowstone national park usa we simultaneously measured water discharge acoustic emissions infrared intensity and visible and infrared video to quantify the energetics and dynamics of eruptions occurring approximately every 3 h we define four phases in the eruption cycle 1 a 28 3 min phase with liquid and steam fountaining with maximum jet velocities of 16 28 m s 1 steam mass fraction of less than 0 01 intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction 2 a 26 8 min posteruption relaxation phase with no discharge from the vent infrared ir and acoustic power oscillations gliding between 30 and 40 s 3 a 59 13 min recharge period during which the geyser is quiescent and progressively refills and 4 a 69 14 min preplay period characterized by a series of 5 10 min long pulses of steam small volumes of liquid water discharge and 50

methane rich fluids in the oceanic crust analyses of fluid inclusions in plutonic rocks recovered from the slow spreading southwest indian ridge swir record ch4 concentrations of 15 40 times those of hydrothermal vent fluids and of basalt hosted volcanic gases and provide the first direct sampling of co2 ch4 h2o h2 c bearing fluids in the oceanic crust compositional thermal and spatial analyses of these fluids are used to model the evolution of volatiles during the crystallization and cooling of mid ocean ridge magma chambers and to assess the potential importance of carbon bearing fluids in geochemical processes in the lower crustal component of hydrothermal systems results from these analyses show that the earliest fluids to be exsolved from the melts are dominated by co2 rich vapors which with progressive fractionation evolved to more h2o rich compositions these later fluids were most likely exsolved under immiscible conditions and involved the development of co2 h2o rich vapors and co2 h2o nacl brines that were trapped during mineral growth as well as during later high temperature fracturing events co2 ch4 h2o rich fluids in olivine and plagioclase minerals that contain up to 30 50 mol co2 and 33 mol ch4 may reflect respeciation of magmatic co2 during cooling and attendant graphite precipitation phase equilibria suggest that these fluids reequilibrated at 500 600 c and at fo2 s 3 log units below to close to qfm conditions alternatively the inclusions may record respeciation of magmatic fluids attendant with the inward diffusion of h2 into the inclusions and reduction of entrapped co2 during degassing and cooling of the gabbros throughout the subsolidus regime subsequent seawater reaction at minimum temperatures of 400 c with mafic rich layers within the gabbroic rocks or with ultramafic material that underlies the plutonic sequence resulted in the formation of ch4 h2o fluids that contain up to 40 mol ch4 molecular h2 and graphite daughter minerals these data provide strong evidence that the ch4 h2o rich fluids produced during serpentinization reactions were trapped under equilibrium conditions in the presence of graphite at very near to qfm conditions the ubiquitous occurrence of ch4 rich fluids in oceanic crustal layer 3 rocks from the swir indicates that these fluids may be a significant and previously unrecognized source for these volatile species in some hydrothermal systems venting on the seafloor and that the deep seated fluids most likely play an important role in the transfer of carbon from the lithosphere to the hydrosphere

anomalous chloride flux discharges from yellowstone national park abstract the chloride concentration of some thermal springs in and adjacent to yellowstone national park is constant through time although their discharge varies seasonally as a result the chloride flux from these springs increases during periods of increased discharge we believe that this is caused by changes in the height of the local groundwater table which affects the discharge of the springs but not their chloride concentration the discharge from mammoth hot springs varies seasonally but its chloride concentration remains constant we take this as evidence that this major thermal feature is derived from orifices that are tapping the local water table close to its surface three of the four major rivers yellowstone snake and falls exiting the park also show an increased chloride flux during the spring runoff that cannot be explained solely by the contribution of snowmelt nor by release of hot spring derived chloride stored in the soil during the winter and released in the spring the increased chloride flux in these rivers is attributed to their draining shallow hot springs similar to those mentioned above in contrast to the yellowstone snake and falls rivers the firehole and gibbon rivers which unite to form the madison river and which collectively drain several major geyser basins display a poor correlation between chloride flux and discharge the cause we believe is that a large part of the thermal water input to these two rivers originated at great depths where the seasonal variation in the height of the water table had a negligible effect on hot spring discharge monitoring of seasonal discharge and chloride concentration of thermal features yields information on the depths at which these thermal features tap the local water table

gas geochemistry of the valles caldera region new mexico and comparisons with gases at yellowstone long valley and other geothermal systems abstract noncondensible gases from hot springs fumaroles and deep wells within the valles caldera geothermal system 210 300 c consist of roughly 98 5 mol co 2 0 5 mol h 2 s and 1 mol other components 3 he 4 he ratios indicate a deep magmatic source r r a up to 6 whereas 13 c co 2 values 3 to 5 do not discriminate between a mantle magmatic source and a source from subjacent hydrothermally altered paleozoic carbonate rocks regional gases from sites within a 50 km radius beyond valles caldera are relatively enriched in co 2 and he but depleted in h 2 s compared to valles gases regional gases have r r a values 1 2 due to more interaction with the crust and or less contribution from the mantle carbon sources for regional co 2 are varied during 1982 1998 repeat analyses of gases from intracaldera sites at sulphur springs showed relatively constant ch 4 h 2 and h 2 s contents the only exception was gas from footbath spring 1987 1993 which experienced increases in these three components during drilling and testing of scientific wells vc 2a and vc 2b present day valles gases contain substantially less n 2 than fluid inclusion gases trapped in deep early stage post caldera vein minerals this suggests that the long lived valles hydrothermal system ca 1 myr has depleted subsurface paleozoic sedimentary rocks of nitrogen when compared with gases from many other geothermal systems valles caldera gases are relatively enriched in he but depleted in ch 4 n 2 and ar in this respect valles gases resemble end member hydrothermal and magmatic gases discharged at hot spots galapagos kilauea and yellowstone

combined raman microprobe spectrometry and microthermometry of fluid inclusions in minerals from igneous rocks of the gardar province south greenland abstract raman microprobe spectrometry has been applied to analysis of the gaseous phase in individual fluid inclusions in minerals from alkalic igneous rock types and associated hydrothermal veins from the gardar province south greenland quantitative analyses are given for co2 ch4 c2h6 h2 and h2s traces of co were observed in one co2 inclusion in conjunction with data from microthermometry the results permit calculation of the bulk chemical composition of entrapped fluids and evaluation of the possible pressure temperature oxygen fugacity and sulphur fugacity during entrapment of the individual fluid inclusions calculated oxygen fugacity values correspond to those of the nno and qfm buffer reactions at temperatures of 300 400 c and pressures of 0 5 1 0 kbar calculated sulphur fugacity values are within the range of normal ore forming solutions log fs2 6 to 10

geothermal solute flux monitoring and the source and fate of solutes in the snake river yellowstone national park wy abstract the combined geothermal discharge from over 10 000 features in yellowstone national park ynp can be can be estimated from the cl flux in the madison yellowstone falls and snake rivers over the last 30 years the cl flux in ynp rivers has been calculated using discharge measurements and cl concentrations determined in discrete water samples and it has been determined that approximately 12 of the cl flux exiting ynp is from the snake river the relationship between electrical conductivity and concentrations of cl and other geothermal solutes was quantified at a monitoring site located downstream from the thermal inputs in the snake river beginning in 2012 continuous 15 min electrical conductivity measurements have been made at the monitoring site combining continuous electrical conductivity and discharge data the cl and other geothermal solute fluxes were determined the 2013 2015 cl fluxes 5 3 5 8 kt yr determined using electrical conductivity are comparable to historical data in addition synoptic water samples and discharge data were obtained from sites along the snake river under low flow conditions of september 2014 the synoptic water study extended 17 km upstream from the monitoring site surface inflows were sampled to identify sources and to quantify solute loading the lewis river was the primary source of cl na k cl sio2 rb and as loads 50 80 in the snake river the largest source of so4 was from the upper snake river 50 most of the ca and mg 50 55 originate from the snake hot springs chloride ca mg na k sio2 f hco3 so4 b li rb and as behave conservatively in the snake river and therefore correlate well with conductivity r2 0 97

analysis of hot springs and associated deposits in yellowstone national park using aster and aviris remote sensing the advanced spaceborne thermal emission and reflection radiometer aster and the airborne visible ir image spectrometer aviris data were used to characterize hot spring deposits in the lower midway and upper geyser basins of yellowstone national park from the visible near infrared vnir to thermal infrared tir wavelengths field observations of these basins provided the critical ground truth for comparison with the remote sensing results fourteen study sites were selected based on diversity in size deposit type and thermal activity field work included detailed site surveys such as land cover analysis photography global positioning system gps data collection radiometric analysis and vnir spectroscopy samples of hot spring deposits geyser deposits and soil were also collected analysis of aster data provided broad scale characteristics of the hot springs and their deposits including the identification of thermal anomalies aviris high spectral resolution short wave infrared swir spectroscopy provided the ability to detect hydrothermally altered minerals as well as a calibration for the multispectral swir aster data from the image analysis differences in these basins were identified including the extent of thermal alteration the location and abundance of alteration minerals and a comparison of active near extinct and extinct geysers we determined the activity level of each region using a combination of the vnir swir tir spectral differences as well as the presence of elevated temperatures detected by the tir subsystem of aster the results of this study are applicable to the exploration of extinct mineralized hydrothermal deposits on both earth and mars

source and fate of inorganic solutes in the gibbon river yellowstone national park wyoming usa ii trace element chemistry the gibbon river in yellowstone national park receives inflows from several geothermal areas and consequently the concentrations of many trace elements are elevated compared to rivers in non geothermal watersheds water samples and discharge measurements were obtained from the gibbon river and its major tributaries near norris geyser basin under the low flow conditions of september 2006 allowing for the identification of solute sources and their downstream fate norris geyser basin and in particular tantalus creek is the largest source of many trace elements al as b ba br cs hg li sb tl w and rees to the gibbon river the chocolate pots area is a major source of fe and mn and the lower gibbon river near terrace spring is the major source of be and mo some of the elevated trace elements are aquatic health concerns as sb and hg and knowing their fate is important most solutes in the gibbon river including as and sb behave conservatively or are minimally attenuated over 29 km of fluvial transport some small attenuation of al fe hg and rees occurs but primarily there is a transformation from the dissolved state to suspended particles with most of these elements still being transported to the madison river dissolved hg and rees loads decrease where the particulate fe increases suggesting sorption onto suspended particulate material attenuation from the water column is substantial for mn with little formation of mn as suspended particulates

hydrogeochemical processes governing the origin transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters abstract the formation of acid mine drainage from metals extraction or natural acid rock drainage and its mixing with surface waters is a complex process that depends on petrology and mineralogy structural geology geomorphology surface water hydrology hydrogeology climatology microbiology chemistry and mining and mineral processing history the concentrations of metals metalloids acidity alkalinity cl f and so 4 2 found in receiving streams rivers and lakes are affected by all of these factors and their interactions remediation of mine sites is an engineering concern but to design a remediation plan without understanding the hydrogeochemical processes of contaminant mobilization can lead to ineffective and excessively costly remediation furthermore remediation needs a goal commensurate with natural background conditions rather than water quality standards that might bear little relation to conditions of a highly mineralized terrain this paper reviews hydrogeochemical generalizations primarily from us geological survey research that enhance our understanding of the origin transport and fate of contaminants released from mined and mineralized areas mobility of potential or actual contaminants from mining and mineral processing activities depends on 1 occurrence is the mineral source of the contaminant actually present 2 abundance is the mineral present in sufficient quantity to make a difference 3 reactivity what are the energetics rates and mechanisms of sorption and mineral dissolution and precipitation relative to the flow rate of the water and 4 hydrology what are the main flow paths for contaminated water estimates of relative proportions of minerals dissolved and precipitated can be made with mass balance calculations if minerals and water compositions along a flow path are known combined with discharge these mass balance estimates quantify the actual weathering rate of pyrite mineralization in the environment and compare reasonably well with laboratory rates of pyrite oxidation except when large quantities of soluble salts and evaporated mine waters have accumulated underground quantitative mineralogy with trace element compositions can substantially improve the identification of source minerals for specific trace elements through mass balances post dissolution sorption and precipitation attenuation reactions depend on the chemical behavior of each element solution composition and ph aqueous speciation temperature and contact time with mineral surfaces for example little metal attenuation occurs in waters of low ph

chloride flux out of yellowstone national park abstract monitoring of the chloride concentration electrical conductivity and discharge was carried out for the four major rivers of yellowstone national park from september 1982 to january 1984 chloride flux out of the park was determined from the measured values of chloride concentration and discharge the annual chloride flux from the park was 5 86 1010 g of this amount 45 was from the madison river drainage basin 32 from the yellowstone river basin 12 from the snake river basin and 11 from the falls river basin of the annual chloride flux from the yellowstone river drainage basin 36 was attributed to the yellowstone lake drainage basin the geothermal contribution to the chloride flux was determined by subtracting the chloride contribution from rock weathering and atmospheric precipitation and is 94 of the total chloride flux calculations of the geothermal chloride flux for each river are given and the implications of an additional chloride flux out of the western park boundary discussed an anomalous increase in chloride flux out of the park was observed for several weeks prior to the mt borah earthquake in central idaho on october 28 1983 reaching a peak value shortly thereafter it is suggested that the rise in flux was a precursor of the earthquake the information in this paper provides baseline data against which future changes in the hydrothermal systems can be measured it also provides measurements related to the thermal contributions from the different drainage basins of the park

tree ring 14c links seismic swarm to co2 spike at yellowstone usa mechanisms to explain swarms of shallow seismicity and inflation deflation cycles at yellowstone caldera western united states commonly invoke episodic escape of magma derived brines or gases from the ductile zone but no correlative changes in the surface efflux of magmatic constituents have ever been documented our analysis of individual growth rings in a tree core from the mud volcano thermal area within the caldera links a sharp 25 drop in 14 c to a local seismic swarm in 1978 the implied fivefold increase in co 2 emissions clearly associates swarm seismicity with upflow of magma derived fluid and shows that pulses of magmatic co 2 can rapidly traverse the 5 km thick brittle zone even through yellowstone9s enormous hydrothermal reservoir the 1978 event predates annual deformation surveys but recognized connections between subsequent seismic swarms and changes in deformation suggest that co 2 might drive both processes

palynofacies investigation of callovian middle jurassic sediments from dsdp site 534 blake bahama basin western central atlantic abstract during the extension of deep sea drilling project dsdp leg 76 a new and previously unpenetrated lithological unit composed mainly of claystones was cored above basalt basement at site 534 in the blake bahama basin the callovian part of the new unit contains interbedded black shales which were hitherto unexpected in this part of the section this paper presents a brief palynological examination of lithofacies kerogen relationships in these sediments and shows that their organic content is almost entirely a function of the re deposition of terrestial and marine organic matter versus the ambient redox conditions of the depositional environment allochthonous organic matter inputs are highest in the interbedded turbidites and decline progressively toward the pelagic black shales in which marine organic matter is comparatively well preserved the significance of various kerogen and palynomorph indices are discussed the study emphasizes the absolute necessity for sedimentologically aware sampling in all palynological and geochemical work on lithologically heterogeneous sequences

temporal variations of geyser water chemistry in the upper geyser basin yellowstone national park usa 1 geysers are rare features that reflect a delicate balance between an abundant supply of water and heat and a unique geometry of fractures and porous rocks between april 2007 and september 2008 we sampled old faithful daisy grand oblong and aurum geysers in yellowstone national park s upper geyser basin and characterized temporal variations in major element chemistry and water isotopes 18o d 3h we compare these temporal variations with temporal trends of geyser eruption intervals gei sio2 concentrations and geothermometry indicate that the geysers are fed by waters ascending from a reservoir with temperatures of 190 to 210 c the studied geysers display small and complex chemical and isotopic seasonal variations and geysers with smaller volume display larger seasonal variations than geysers with larger volumes aurum and oblong geysers contain detectable tritium concentrations suggesting that erupted water contains some modern meteoric water we propose that seasonal gei variations result from varying degrees of evaporation meteoric water recharge water table fluctuations and possible hydraulic interaction with the adjacent firehole river we demonstrate that the concentrations of major dissolved species in old faithful geyser have remained nearly constant since 1884 despite large changes in old faithful s eruption intervals suggesting that no major changes have occurred in the hydrothermal system of the upper geyser basin for 120 years our data set provides a baseline for monitoring future changes in geyser activity that might result from varying climate earthquakes and changes in heat flow from the underlying magmatic system

volatile emissions and gas geochemistry of hot spring basin yellowstone national park usa abstract we characterize and quantify volatile emissions at hot spring basin hsb a large acid sulfate region that lies just outside the northeastern edge of the 640 ka yellowstone caldera relative to other thermal areas in yellowstone hsb gases are rich in he and h2 and mildly enriched in ch4 and h2s gas compositions are consistent with boiling directly off a deep geothermal liquid at depth as it migrates toward the surface this fluid and the gases evolved from it carries geochemical signatures of magmatic volatiles and water rock reactions with multiple crustal sources including limestones or quartz rich sediments with low k u or 40 ar 4 he variations in gas chemistry across the region reflect reservoir heterogeneity and variable degrees of boiling gas geothermometer temperatures approach 300 c and suggest that the reservoir feeding hsb is one of the hottest at yellowstone diffuse co2 flux in the western basin of hsb as measured by accumulation chamber methods is similar in magnitude to other acid sulfate areas of yellowstone and is well correlated to shallow soil temperatures the extrapolation of diffuse co2 fluxes across all the thermal altered area suggests that 410 140 t d 1 co2 are emitted at hsb vent emissions not included diffuse fluxes of h2s were measured in yellowstone for the first time and likely exceed 2 4 t d 1 at hsb comparing estimates of the total estimated diffuse h2s emission to the amount of sulfur as so42 in streams indicates 50 of the original h2s in the gas emission is lost into shallow groundwater precipitated as native sulfur or vented through fumaroles we estimate the heat output of hsb as 140 370 mw using co2 as a tracer for steam condensate but not including the contribution from fumaroles and hydrothermal vents overall the diffuse heat and volatile fluxes of hsb are as great as some active volcanoes but they are a small fraction 1 3 for co2 2 8 for heat of that estimated for the entire yellowstone system

volatiles associated with alkaline igneous rift activity fluid inclusions in the ilimaussaq intrusion and the gardar granitic complexes south greenland abstract fluid inclusions in minerals from si oversaturated and si undersaturated alkalic igneous complexes belonging to the precambrian gardar rift province in south greenland contain distinctly different carbon bearing gases granites and quartz syenites are characterized by co2 and only minor ch4 whereas agpaitic nepheline syenites are dominated by hydrocarbons essentially ch4 and contain only insignificant amounts of co2 and or co in the alkaline ilimaussaq intrusion the hydrocarbon rich gases may well reflect equilibration with graphite at magmatic temperatures and at oxygen fugacities approaching those defined by the synthetic mw buffer reaction in general formation of hydrocarbon gases in agpaitic nepheline syenites is considered to reflect the fulfillment of three basic conditions 1 low oxygen fugacities 2 a wide temperature range of crystallization and a low temperature solidus and 3 retention of volatiles during crystallization the characteristic carbon bearing vapour associated with continental alkaline igneous activity is however considered to be co2

variations in kerogen densities of sediments from the orinoco delta venezuela abstract a method employing the coulter counter technique was used in determining kerogen density for recent sediments of the orinoco delta these sediments contain essentially terrestrial humic organic matter and have kerogen densities ranging from 1 32 to 1 72 g ml 1 with an average of 1 48 g ml 1 a strong correlation was found to exist between kerogen density and offshore distance and depth in the orinoco delta kerogen density varies with offshore distance and depth decreasing consistently at the rates of 0 015 and 4 g ml 1 km 1 respectively the heavy kerogens are associated with shallow near shore areas while lighter kerogens are found in the deep offshore hence offshore distance and depth could be said to be a function of kerogen density

source and fate of inorganic solutes in the gibbon river yellowstone national park wyoming usa i low flow discharge and major solute chemistry abstract the gibbon river in yellowstone national park ynp is an important natural resource and habitat for fisheries and wildlife however the gibbon river differs from most other mountain rivers because its chemistry is affected by several geothermal sources including norris geyser basin chocolate pots gibbon geyser basin beryl spring and terrace spring norris geyser basin is one of the most dynamic geothermal areas in ynp and the water discharging from norris is much more acidic ph 3 than other geothermal basins in the upper madison drainage gibbon and firehole rivers water samples and discharge data were obtained from the gibbon river and its major tributaries near norris geyser basin under the low flow conditions of september 2006 surface inflows from norris geyser basin were sampled to identify point sources and to quantify solute loading to the gibbon river the source and fate of the major solutes ca mg na k sio 2 cl f hco 3 so 4 no 3 and nh 4 in the gibbon river were determined in this study and these results may provide an important link in understanding the health of the ecosystem and the behavior of many trace solutes norris geyser basin is the primary source of na k cl so 4 and n loads 35 58 in the gibbon river the largest source of hco 3 and f is in the lower gibbon river reach most of the ca and mg originate in the gibbon river upstream from norris geyser basin all the major solutes behave conservatively except for nh 4 which decreased substantially downstream from gibbon geyser basin and sio 2 small amounts of which precipitated on mixing of thermal drainage with the river as much as 9 14 of the river discharge at the gage is from thermal flows during this period

extremely reducing conditions reached during basaltic intrusion in organic matter bearing sediments redox conditions in magma are widely interpreted as internally buffered and closely related to that of their mantle source regions we use thermodynamic calculations to show that high temperature interaction between magma and organic matter can lead to a dramatic reduction of the magma redox state and significant departure from that of the original source field studies provide direct evidence of the process that we describe with reported occurrences of graphite and native iron in igneous mafic rocks implying very reducing conditions that are almost unknown in average terrestrial magmas we calculate that the addition of 0 6 wt organic matter in the form of ch or ch2 to a standard basalt triggers graphite and native iron crystallization at depths of few hundred meters interaction with organic matter also profoundly affects the abundance and the redox state of the gases in equilibrium with the magma which are co dominated with h2 as the second most abundant species on a molar basis h2o and co2 being minor constituents the assimilation of only 0 1 wt organic matter by a basalt causes a decrease in its oxygen fugacity of 2 orders of magnitude the assimilation of 0 6 wt organic matter at depths 500 m implies minimum co content in the magma of 1 wt other gas components being less than 0 1 wt in the light of our calculations we suggest that the production of native iron bearing lava flows and associated intrusions was most likely accompanied by degassing of co rich gases whose fluxes depended on the magma production rates

p and s velocity structure of the yellowstone volcanic field from local earthquake and controlled source tomography the three dimensional p and s velocity from vp vs ratios distribution and improved hypocenters for the yellowstone volcanic field have been determined from inversion of first arrival times from 7942 local earthquakes and 16 controlled source explosions the p velocity model has an rms residual of 0 09 s whereas the vp vs ratio model calculated from 511 earthquakes has an rms residual of 0 29 s high p and s velocities outside the yellowstone caldera represent thermally undisturbed basement and sedimentary rocks a caldera wide 15 decrease from regional p velocities at depths of 6 to 12 km is coincident with a 60 mgal gravity anomaly and is interpreted as a hot subsolidus granitic batholith with a quasi plastic rheology localized 30 reductions from regional seismic velocities and higher vp vs ratios 8 km beneath yellowstone s resurgent domes are interpreted as partial melts and vestigial magma systems associated with youthful less than 2 ma silicic volcanism additional low seismic velocities and vp vs ratios and a 20 mgal gravity low less than 4 km beneath the northeast caldera rim are interpreted as a hydrothermal fracture zone thermally driven by underlying partial melt hypocenters relocated with the three dimensional p velocity model show subparallel alignment with nw se trending postcaldera volcanic vents and normal faults northwest of the caldera focal depths of relocated earthquakes decrease from more than 11 km outside the caldera to less than 6 km within the caldera reflecting thinning and heating of the seismogenic crust

the ilugissoq graphite andesite volcano nuussuaq central west greenland abstract the ilugissoq graphite andesite volcano on nuussuaq belongs to the asuk member of the paleocene vaigat formation it is the largest eruption site within the vaigat formation and is recognized as the source of the majority of the graphite andesite tuffs found in marine sediments in central nuussuaq the volcano consists exclusively of pyroclastic rocks containing a diverse lithic assemblage including sediment xenoliths the primary pyroclastic fragments consist of magnesian andesite with several weight percent of graphite which formed when mafic magma established a shallow level magma reservoir beneath the eruption site and within older clastic sediments from the nuussuaq basin magma modified mudstone is completely dominant in the xenolith assemblage and attests that the graphite andesite originated through prolonged high temperature assimilation of mudstone the eruptions took place on a marine shelf consisting of picritic hyaloclastites and subaqueous crater mounds the volcano consists of four overlapping crater cones aligned along a more than 4 km long nnw sse oriented fissure system two cones barely reached sea level whereas the other two reached up to 200 m above the sea the morphology of the pyroclastic rocks demonstrates that the volcano evolved through phreatomagmatic activity which diminished with time the magma never degassed sufficiently to reach a subaerial lava stage a moderate primary gas pressure well in excess of 100 bars in the graphite andesite magma facilitated the phreatomagmatic explosions which created the ilugissoq volcano the rocks of the volcano are rich in graphite and contain little or no native iron in comparison the contemporaneous and chemically similar subaerial lavas and breccias from disko and nuussuaq contain less graphite and more iron the differences are considered to be due to the extremely pressure dependent redox sensitivity of carbon oxygen equilibria in the range 1 bar the lavas to 500 bars the ilugissoq volcano eruptions in the ilugissoq volcano must have been accompanied by intense co and co2 emanations which would have represented a lethal hazard for all animal life in the volcano s surroundings

reduced magmatic fluids in basalt from the island of disko central west greenland abstract fluid and melt inclusions in minerals of two native iron bearing dyke rocks from disko greenland were investigated using heating and cooling microscopic techniques the melt inclusions in olivine are homogenized at temperatures of 1170 1200 c the melts are characterized by high sio 2 k 2 o and tio 2 and low mgo contents the co existence of combined melt fluid gas inclusions in olivine implies that the olivine phenocrysts crystallized from a heterogeneous magma at low pressure gas bubbles were investigated in the glass of the rock water and four crystalline phases were observed at room and low temperatures on the walls of the bubbles serpentine naphthalene clathrate and an unknown phase the complex composition of trapped volatiles is reflected in considerable ranges of clathrate melting and solidus temperatures 20 to 7 5 c and 82 6 to 73 c respectively melt equilibrium with metallic iron at t 1450 k suggests that log f o 2 13 95 the calculated composition of c o h fluid in equilibrium with fe fe 3 c and fes is characterized by high ch 4 and h 2 contents during cooling at the postmagmatic stage polymerization proceeds and heavy hydrocarbons are formed inside vesicles the presence of organic compounds in inclusions trapped at a magmatic stage is a natural consequence of unusual reducing condition during crystallization

monitoring super volcanoes geophysical and geochemical signals at yellowstone and other large caldera systems earth s largest calderas form as the ground collapses during immense volcanic eruptions when hundreds to thousands of cubic kilometres of magma are explosively withdrawn from the earth s crust over a period of days to weeks continuing long after such great eruptions the resulting calderas often exhibit pronounced unrest with frequent earthquakes alternating uplift and subsidence of the ground and considerable heat and mass flux because many active and extinct calderas show evidence for repetition of large eruptions such systems demand detailed scientific study and monitoring two calderas in north america yellowstone wyoming and long valley california are in areas of youthful tectonic complexity scientists strive to understand the signals generated when tectonic volcanic and hydrothermal hot ground water processes intersect one obstacle to accurate forecasting of large volcanic events is humanity s lack of familiarity with the signals leading up to the largest class of volcanic eruptions accordingly it may be difficult to recognize the difference between smaller and larger eruptions to prepare ourselves and society scientists must scrutinize a spectrum of volcanic signals and assess the many factors contributing to unrest and toward diverse modes of eruption

heat flow in vapor dominated areas of the yellowstone plateau volcanic field implications for the thermal budget of the yellowstone caldera the yellowstone caldera the 0 11 km 2 obsidian pool thermal area opta and the 0 25 km 2 solfatara plateau thermal area spta conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at 600 locations and from laboratory measurements of soil properties the conductive heat output is 3 6 0 4 mw and 7 5 0 4 mw from the opta and the spta respectively the advective heat output from soils is 1 3 0 3 mw and 1 2 0 3 mw from the opta and the spta respectively and the heat output from thermal pools in the opta is 6 8 1 4 mw these estimates result in a total heat output of 11 8 1 4 mw and 8 8 0 4 mw from opta and spta respectively focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor

limitations of use of organic petrographic techniques for identification of petroleum source rocks organic petrographic and organic geochemical studies have been conducted on 58 sediment samples of differing ages and depositional environments in this study interpretations of petroleum source rock potential based on data from transmitted light microscopy show a poor correlation with those derived from chemical data this lack of correlation arises from the failure to distinguish consistently between hydrogen poor and hydrogen rich amorphous organic matter and inability to detect hydrogen rich components exinite and resinite in coal fragments interpretations based on data from reflected light microscopy show a better correlation with those derived from chemical studies but difficulties still remain these difficulties arise from inability except on the basis of luorescence intensity to distinguish hydrogen rich from hydrogen poor organic matter in a finely dispersed state

radiocarbon dating of silica sinter deposits in shallow drill cores from the upper geyser basin yellowstone national park abstract to explore the timing of hydrothermal activity at the upper geyser basin ugb in yellowstone national park we obtained seven new accelerator mass spectrometry ams radiocarbon 14 c ages of carbonaceous material trapped within siliceous sinter five samples came from depths of 15 152 cm within the y 1 well and two samples were from well y 7 depths of 24 cm and 122 cm these two wells at black sand and biscuit basins respectively were drilled in 1967 as part of a scientific drilling program by the u s geological survey white et al 1975 even with samples as small as 15 g we obtained sufficient carbonaceous material a mixture of thermophilic mats pollen and charcoal for the 14 c analyses apparent time of deposition ranged from 3775 25 and 2910 30 14 c years bp at the top of the cores to about 8000 years bp at the bottom the dates are consistent with variable rates of sinter formation at individual sites within the ugb over the holocene on a basin wide scale though these and other existing 14 c dates hint that hydrothermal activity at the ugb may have been continuous throughout the holocene

generation and evolution of hydrothermal fluids at yellowstone insights from the heart lake geyser basin 1 we sampled fumaroles and hot springs from the heart lake geyser basin hlgb measured water and gas discharge and estimated heat and mass flux from this geothermal area in 2009 the combined data set reveals that diverse fluids share an origin by mixing of deep solute rich parent water with dilute heated meteoric water accompanied by subsequent boiling a variety of chemical and isotopic geothermometers are consistent with a parent water that equilibrates with rocks at 205 c 10 c and then undergoes 21 2 adiabatic boiling measured diffuse co2 flux and fumarole compositions are consistent with an initial dissolved co2 concentration of 21 7 mmol upon arrival at the caldera boundary and prior to southeast flow boiling and discharge along the witch creek drainage the calculated advective flow from the basin is 78 16 l s 1of parent thermal water corresponding to 68 14 mw or 1 of the estimated thermal flux from yellowstone helium and carbon isotopes reveal minor addition of locally derived crustal biogenic and meteoric gases as this fluid boils and degasses reducing the he isotope ratio rc ra from 2 91 to 1 09 the hlgb is one of the few thermal areas at yellowstone that approaches a closed system where a series of progressively boiled waters can be sampled along with related steam and noncondensable gas at other yellowstone locations steam and gas are found without associated neutral cl waters e g hot spring basin or cl rich waters emerge without significant associated steam and gas upper geyser basin

the effects of large igneous provinces on the global carbon and sulphur cycles abstract the correlation between large igneous provinces lips extinction events and rapid climate change suggests that volcanism can have a detrimental impact on earth surface conditions changes in atmospheric and ocean chemistry particularly the climate sensitive carbon and sulphur cycles are among the most probable processes for inducing global environmental stress however the interactions and feedbacks between volcanism and these cycles are numerous and complex making the characterisation of the response to a lip challenging here we summarise the sources and sinks of carbon and sulphur from large scale volcanism and magmatism using information from modern and ancient systems for the sources we review the current understanding of volcanic emissions and explore the relative contributions and importance of magma derived degassing versus volatile release from sediments affected by igneous intrusions and lava in addition we explore the various ways in which lips can reduce atmospheric concentrations of these same elements the relative influences of each source and sink are in part determined by the mode of lip emplacement and eruption style along with the subsequent timescales of such effects we focus on a few key examples including the siberian traps the parana etendeka and the central atlantic magmatic province camp to demonstrate how the environmental impact can vary considerably with differing modes of emplacement lip duration and eruption styles in particular we show that the host rocks can have a dominant role as a source or sink of emissions depending on the lithologies affected by the lip emplacement

sulfur geochemistry of hydrothermal waters in yellowstone national park i the origin of thiosulfate in hot spring waters thiosulfate s sub 2 o sub 3 sup 2 minus polythionate s sub x o sub 6 sup 2 minus dissolved sulfide h sub 2 s and sulfate so sub 4 sup 2 minus concentrations in thirty nine alkaline and acidic springs in yellowstone national park ynp were determined the analyses were conducted on site using ion chromatography for thiosulfate polythionate and sulfate and using colorimetry for dissolved sulfide thiosulfate was detected at concentrations typically less than 2 micro mol l in neutral and alkaline chloride springs with low sulfate concentrations cl sup minus so sub 4 sup 2 minus 25 the thiosulfate concentration levels are about one to two orders of magnitude lower than the concentration of dissolved sulfide in these springs in most acid sulfate and acid sulfate chloride springs cl sup minus so sub 4 sup 2 minus 10 thiosulfate concentrations were also typically lower than 2 micro mol l however in some chloride springs enriched with sulfate cl sup minus so sub 4 sup 2 minus between 10 and 25 thiosulfate was found at concentrations ranging from 9 to 95 micro mol l higher than the concentrations of dissolved sulfide in these waters polythionate was detected only in cinder pool norris geyser basin at concentrations up to 8 micro mol l with an average s chain length from 4 1 to 4 9 sulfur atoms the results indicate that no thiosulfate occurs in the deeper parts of themore hydrothermal system thiosulfate may form however from 1 hydrolysis of native sulfur by hydrothermal solutions in the shallower parts 50 m of the system 2 oxidation of dissolved sulfide upon mixing of a deep hydrothermal water with aerated shallow groundwater and 3 the oxidation of dissolved sulfide by dissolved oxygen upon discharge of the hot spring upon discharge of a sulfide containing hydrothermal water oxidation proceeds rapidly as atmospheric oxygen enters the water the transfer of oxygen is particularly effective if the hydrothermal discharge is turbulent and has a large surface area less

sources fate and flux of riverine solutes in the southwest yellowstone plateau volcanic field usa abstract since the 1970s temporal variations of hydrothermal discharge and thermal output from the numerous hydrothermal features in the yellowstone plateau volcanic field ypvf have been studied by measuring the chloride flux in the major rivers in this study the sources fate and flux of solutes in the fall river and its major tributaries in southwest yellowstone national park were determined the considerable precipitation in southwest ypvf and high groundwater flow through quaternary rhyolites results in river solute fluxes that originate from shallow non thermal groundwater and deep thermal water specific conductance serves as a surrogate measure for thirteen riverine solute concentrations combining continuous 15 minute specific conductance and discharge data the annual chloride arsenic fluoride and silica fluxes from the fall river were determined to be 11 5 25 and 19 of the total flux exiting ypvf approximately 11 of the fall river chloride flux is from non thermal waters which is larger than the previous estimate of 4 to 6 furthermore a large proportion of fluoride and silica in the fall river are derived from water rock interaction in the shallow non thermal groundwater system and the non thermal weathering rate 30 2 t yr km2 is higher than other rivers draining the yellowstone caldera consequently 73 3 of the annual total dissolved solid flux in the fall river is from thermal sources synoptic sampling of river water and discharge measurements was performed during low flow conditions that allowed for the determination of solute sources and their downstream fate it was determined that chloride sodium arsenic rubidium lithium and boron are primarily 89 associated with thermal waters and the bechler river is the primary source of most hydrothermal solutes in the fall river but the major source of arsenic is boundary creek using the chloride inventory method the thermal water discharge from several thermal areas was also determined

tracking crystallinity in siliceous hot spring deposits siliceous hot spring deposits sinters entrap paleoenvironmentally significant components and are used as extreme environment analogs in the search for early earth and extraterrestrial life however sinters undergo a series of textural and mineralogical changes during diagenesis that can modify and overprint original environmental signals for ancient hydrothermal settings including those close to the dawn of life these transformations have long since occurred so that study of diagenetic processes and effects is best undertaken in much younger deposits still undergoing change three young sinters preserve the entire diagenetic sequence of silica phases from opal a to quartz the 6000 to 11 500 years bp 70 years sinter at steamboat springs nevada the 1600 1900 160 years bp opal mound sinter at roosevelt hot springs utah and the 456 35 years bp deposit at sinter island taupo volcanic zone new zealand provide an opportunity to track crystallographic mineralogic and morphologic transitions of sinter diagenesis using standard and new analytical approaches worldwide sinter forms from cooling alkali chloride waters as noncrystalline opal a transforming first into noncrystalline opal a ct then paracrystalline opal ct moganite paracrystalline opal c and eventually to microcrystalline quartz in this study these changes were identified by the novel and combined application of electron backscatter diffraction x ray powder diffraction and scanning electron and optical microscopy techniques we show that mineralogical changes precede morphological and accompanied crystallographic transformations during this modification silica particles grow and shrink several times from the micron to nano meter scales via dissolution reprecipitation and recrystallization and diagenesis follows the ostwald step rule all deposits followed nearly identical diagenetic pathways with time as the only variable in the march toward physicochemically stable quartz crystals diagenesis alters original environmental signatures trapped within sinters after five silica phase changes filamentous microfossils are modified but still remain recognizable within sinter from the opal mound and steamboat springs deposits and during the opal a to opal ct silica phase transformations at sinter island therefore delineating diagenetic components and how they affect sinters is necessary to accurately identify biosignals from ancient hot spring deposits

hydrothermal petroleums from yellowstone national park wyoming u s a abstract in yellowstone national park oil is actively discharging with thermal waters at several widely separated thermal areas samples from two locations were studied petroleum from calcite springs occurs as vapor condensates in steam vents detailed geochemical analyses show a complex origin for the petroleum fluid deeply buried hydrothermally altered sedimentary rocks are believed to have contributed a high temperature pyrolysate consisting largely of polynuclear aromatic hydrocarbons and heterocyclic compounds shallow sedimentary rocks which are also hydrothermally altered have contributed large amounts of aromatic and polar compounds as well as minor amounts of hydrocarbons the permian phosphoria formation is suggested as a likely source rock for the bulk of the oils autochthonous pyrolysates and lipids from thermally altered surface and near surface bacterial and land plant debris have also been introduced to the vents the latter may have been introduced by downward percolating meteoric water the oil from rainbow springs is a highly paraffinic low s crude oil depleted in light hydrocarbons unlike the calcite springs samples the oil from rainbow springs is believed to have originated from a single sedimentary source rock with little or no hydrocarbon contributions from surface biota the oil contains a unique molecular marker assemblage that suggests both gymnosperm and angiosperm input and places the age of the source unit in the tertiary consideration of the local stratigraphy and water temperatures limits the probable source zone to the eocene aycross formation an intra volcanic lacustrine mudstone calculation of deep water temperatures indicates that this unit is exposed to thermal waters in an extensive near surface aquifer such conditions are consistent with the widespread surface manifestations and biomarker kinetic models consideration of the petroleum chemistry and regional hydrodynamics indicates that the yellowstone park oils did not migrate into the park from distant sources the chemical data are also inconsistent with the oils being generated and trapped prior to tertiary volcanism at both calcite springs and rainbow springs oil generation appears to be contemporaneous and is attributed to thermal alteration of relatively shallow sedimentary rocks by hydrothermal fluids

remotely triggered seismicity in the yellowstone national park region by the 2002 mw 7 9 denali fault earthquake alaska coincident with the arrival of low frequency large amplitude surface waves of the mw 7 9 denali fault earthquake dfe an abrupt increase in seismicity was observed in the yellowstone national park region despite the large epicentral distance of 3100 km within the first 24 hr following the dfe mainshock we located more than 250 earthquakes which occurred throughout the entire yellowstone na tional park region the elevated seismicity rate continued for about 30 days and followed a modified omori law decay with a p value of 1 02 0 07 for a declus tered earthquake catalog the seismicity following the 2002 dfe uniquely stands out with a significance of 30r the increase in seismicity occurred over all magnitude bands in general we observed that seismicity following the dfe outlined the spatial pattern of past seismicity routinely observed in the yellowstone national parkregion however we found significant differences in triggered seismicity inside and outside the caldera earthquakes inside the yellowstone caldera occurred preferentially as clusters close to major hydrothermal systems were of larger magnitude and seis micity decayed more rapidly this suggests that either different trigger mechanisms were operating inside and outside the caldera or that the crust responded differently to the same trigger mechanism depending on its different mechanicalstate compared with other sites that experienced remote earthquake triggering following the 2002 dfe yellowstone showed the most vigorous earthquake activity we attribute this to strong directivity effects of the dfe which caused relatively large peak dynamic stresses 0 16 0 22 mpa in yellowstone and to the volcanic nature of yellowstone

spatial and temporal geochemical trends in the hydrothermal system of yellowstone national park inferences from river solute fluxes we present and analyze a chemical dataset that includes the concentrations and fluxes of hco3 s o4 c l and f in the major rivers draining yellowstone national park ynp for the 2002 2004 water years 1 october 2001 30 september 2004 the total molar flux in all rivers decreases in the following order hco3 ncl nso4 nf but each river is characterized by a distinct chemical composition implying large scale spatial heterogeneity in the inputs of the various solutes the data also display nonuniform temporal trends whereas solute concentrations and fluxes are nearly constant during base flow conditions concentrations decrease solute fluxes increase and hco3 cl and so4 cl increase during the late spring high flow period hco3 so4 decreases with increasing discharge in the madison and falls rivers but increases with discharge in the yellowstone and snake rivers the non linear relations between solute concentrations and river discharge and the change in anion ratios associated with spring runoff are explained by mixing between two components 1 a component that is discharged during base flow conditions and 2 a component associated with snow melt runoff characterized by higher hco3 cl and so4 cl the fraction of the second component is greater in the yellowstone and snake rivers which host lakes in their drainage basins and where a large fraction of the solute flux follows thaw of ice cover in the spring months although the total river hco3 flux is larger than the flux of other solutes hco3 cl 3 the co2 equivalent flux is only 1 of the estimated emission of magmatic co2 soil emissions from yellowstone no anomalous solute flux in response to perturbations in the hydrothermal system was observed possibly because gage locations are too distant from areas of disturbance or because of the relatively low sampling frequency in order to detect changes in river hydrothermal solute fluxes sampling at higher frequencies with better spatial coverage would be required our analysis also suggests that it might be more feasible to detect large scale heating or cooling of the hydrothermal system by tracking changes in gas and steam flux than by tracking changes in river solute flux published by elsevier b v

aspects of depositional processes of organic matter in sedimentary basins abstract quantitative evaluation of source rocks is a prerequisite for assessing realistic petroleum potential in target basins such an evaluation includes information about the actual occurrence of organic rich beds their stratigraphic placement specific locations in sedimentary sequences lateral extension geometry at the scale of the basin and their organic facies variations richness and quality to achieve this evaluation current methods rely on analytical data alone for several years an attempt has been made to elaborate a predictive approach based on the integration of the various factors controlling the accumulation and distribution of organic matter in sedimentary basins in order to try to model the process the main effort has been devoted to the control of the production of biomass according to paleogeography and paleoclimatology and to the control of the degradation of organic matter according to the development of oxygen starved water bodies depositional processes which are certainly a key factor to understand the internal variations and the distribution of organic bearing sediments have been largely overlooked examples of modern environments e g black sea caspian sea lake bogoria show that the distribution of the organic matter in anoxic basins is generally organized in a concentric pattern with a centripetal increase of organic content towards the depocenters where the sediment thickness is the greatest such a feature which can be related to the hydrodynamic properties of the organic particles is of paramount importance as far as the distribution of petroleum potential is concerned this centripetal concept with its implications for source rocks evaluation is well exemplified in the lower jurassic of the north sea and in the lias of the paris basin however this pattern can be strongly affected in anoxic basins when extensive gravity transport mechanisms cause redeposition of sediments in such a situation sediments including their specific organic contents are redistributed along transit pathways in lake tanganyika these modes of transport drive a significant amount of altered organic matter towards the deepest parts of the basin resulting in a marked lateral heterogeneity of the organic facies in the bottom sediments similar processes might contribute to the complex pattern of the distribution of organic facies seen in the upper jurassic of the north sea on the other hand gravity flows can introduce organic rich sediments into basins where environmental conditions would otherwise have been unfavorable for organic accumulation a dramatic example of such a situation is provided by the several hundred metres thick sequence of organic rich turbidites and debris flows deposited since the late miocene at the base of the continental slope off south west africa

hydrothermal changes related to earthquake activity at mud volcano yellowstone national park wyoming the mud volcano hydrothermal area in yellowstone national park is near the intersection of a 20 km long zone of northeast trending normal faults with the eastern resurgent dome within the 600 000 year old yellowstone caldera recent crustal uplift along the northeast trending axis of the caldera is at a maximum 700 mm since 1923 near the mud volcano area from 1973 through april 1978 less than 10 earthquakes largest m 2 4 were located within 3 km of the mud volcano area in may 1978 earthquakes began occurring beneath the hydrothermal area at depths of 1 to 5 km the seismic activity continued until the end of november with intense swarms 100 events per hour occurring on october 23 and november 7 the largest event m 3 1 occurred on november 14 and at least 8 events were m 2 5 or larger in december 1978 heat flux in the mud volcano hydrothermal features began increasing along a 2 km long northeast trending zone existing mud cauldrons became more active new mud cauldrons and fumeroles were formed and vegetation primarily lodgepole pine was killed by increased soil temperature the increase in heat flux continued through july 1979 then gradually declined reaching the early 1978 level by june 1980 the spatial and temporal association of earthquakes and increased hydrothermal activity at mud volcano suggests that the seismic activity expanded preexisting fracture systems premitting increased fluid flow from depths of several kilometers

early diagenesis of marine organic matter alteration of the carbon isotopic composition in two distal carbonate turbidites labelled a and e from the madeira abyssal plain oxidation of organic matter om has been accompanied by a reduction in hydrogen index hi and change in the isotopic composition of carbon since the emplacement of turbidite 0 5 ka ago 35 of the om in the upper part has been oxidised by oxygen and nitrate diffusing from sea water into the sediment there is an accompanying decrease of 0 3 in 13c om and a decrease of 25 in hi turbidite e was emplaced about 73 ka and was exposed to bottom water for 12 3 ka before being buried beneath later turbidites during exposure oxygen and nitrate diffused into its upper part and oxidised 50 of the toc without an accompanying change in isotopic composition further oxidation of the more refactory organic components decreased toc by a further 25 and decreased 13c by 2 5 oxidation also reduced hi by 50 from originally low values unless corrected for the isotopic changes accompanying extended oxic and suboxic degradation of organic matter in sediments will give rise to erroneous estimates of marine terrestrial om ratios