prompt penetration electric fields ppefs and their ionospheric effects during the great magnetic storm of 30 31 october 2003 1 we explore the ionospheric effects of prompt penetration electric fields ppefs for a variety of interplanetary magnetic field directions we use the great magnetic storm of 30 31 october as an example of ppef effects for intense southward interplanetary magnetic fields imfs inward plasma sheet convection occurs with the result of magnetospheric ring current formation and an intense magnetic storm concurrent with the above positive phase ionospheric storms occur in the dayside and negative phase ionospheric storms occur on the nightside the topics of this paper the dayside ionospheric storms due to ppefs are characterized by transport of near equatorial plasma to higher altitudes and latitudes forming a giant plasma fountain these features are part of what is called the dayside ionospheric superfountain dis for these southward imfs dusk and dawn plasma are predicted to be transported toward the dayside for northward imfs negative phase ionospheric storms are expected on the dayside if the ppefs indeed reach that region of space imf by components are expected to have weak or neglible ionospheric effects on the basis of ppef arguments intervals of imf by should not be related to geomagnetic storms they are not imf by intervals should however cause a shearing of the magnetotail a feature that has been previously reported in the literature

a calculation of ionospheric currents due to semidiurnal antisymmetric tides the fully developed equivalent circuit method is used to calculate the ionospheric electric current flow due to the 2 3 and 2 5 tidal modes the 2 5 mode currents are of negligibly small amplitude the 2 3 current pattern has meridional currents in the same direction at a given local time in both north and south hemispheres there is also sometimes a minimum in the zonal current around 10 degree dip latitude and the equatorial electrojet pattern may be different in different longitude zones these features may be possible explanations of 1 the meridional current pattern observed at saint santin 2 current flows on abnormal quiet days aqds 3 the reverse equatorial electrojet 4 the seasonal phase anomaly in the lunar geomagnetic tide and 5 the invasion of one hemisphere s current pattern by that from the opposite hemisphere the recent detection of antisymmetric semidiurnal winds just below the dynamo region further demonstrates the importance of these modes

midnight temperature maximum mtm in whole atmosphere model wam simulations 1 discovered almost four decades ago the midnight temperature maximum mtm with typical magnitudes of 50 100 k has been regularly observed by satellite and ground based instruments in the tropical upper thermosphere although several mechanisms have been suggested to explain the phenomenon previous attempts to reproduce it with comprehensive thermosphere ionosphere models have been unsuccessful first long term simulations with the whole atmosphere model wam reveal the presence of a realistically prominent mtm and reproduce the salient features of its daily seasonal and latitudinal variability preliminary analysis indicates that the feature may be traced down to the lower thermosphere where it is manifested primarily in the form of an upward propagating terdiurnal tidal wave its spectrum expands to higher order zonal wavenumbers and frequencies and its phase advances to near midnight higher up in the thermosphere possible mechanisms generating this wave may involve nonlinear interactions between other tidal harmonics originating in the middle and lower atmosphere our results thus suggest that the mtm is yet another phenomenon driven by dynamical links between the lower and upper atmosphere and ionosphere

xenon isotopes in archean and proterozoic insoluble organic matter a robust indicator of syngenecity abstract insoluble organic materials kerogens isolated from ancient sedimentary rocks provide unique insights into the evolution of early life however establishing whether these kerogens are indeed syngenetic with the deposition of associated sedimentary host rocks or contain contribution from episodes of secondary deposition is not straightforward novel geochemical criterions are therefore required to test the syngenetic origin of archean organic materials on the one hand the occurrence of mass independent fractionation of sulphur isotopes mif s provides a tool to test the archean origin of ancient sedimentary rocks determining the isotope composition of sulphur within kerogens whilst limiting the contribution from associated minerals e g nano pyrites is however challenging on the other hand the xe isotope composition of the archean atmosphere has been shown to present enrichments in the light isotopes relative to its modern composition together with a mono isotopic deficit in 129xe given that the isotopic composition of atmospheric xe evolved through time by mass dependent fractionation mdf until 2 5 to 2 0 ga the degree of mdf of xe isotopes trapped in kerogens could provide a time stamp for the last chemical equilibration between organic matter and the atmosphere however the extent to which geological processes could affect the signature of xe trapped in ancient kerogen remains unclear in this contribution we present new ar kr and xe isotopic data for four kerogens isolated from 3 4 to 1 8 gy old cherts and confirm that xe isotopes from the archean atmosphere can be retained within kerogens however new xe derived model ages are lower than expected from the ages of host rocks indicating that initially trapped xe components were at least partially lost and or mixed together with some xe carried out by younger generations of organic materials therefore complicating the xe based dating method whilst non null 33s values and 129xe deficits relative to modern atmosphere constitute reliable imprints from the archean atmosphere using xe isotopes to provide information on the syngenetic origin of ancient organic matter appears to be a promising but not unequivocal tool that calls for further analytical development

diffusive separation of noble gases and noble gas abundance patterns in sedimentary rocks the mechanisms responsible for noble gas concentrations abundance patterns and strong retentivity in sedimentary lithologies remain poorly explained diffusion controlled fractionation of noble gases is modeled and examined as an explanation for the absolute and relative abundances of noble gases observed in sediments since the physical properties of the noble gases are strong functions of atomic mass the individual diffusion coefficients adsorption coefficients and atomic radii combine to impede heavy noble gas xe diffusion relative to light noble gas ne diffusion filling of lithic grains half spaces by diffusive processes thus produces ne enrichments in the early and middle stages of the filling process with f ne values similar to that observed in volcanic glasses emptying lithic grains half spaces produces a xe enriched residual in the late but not final stages of the process producing f xe values similar to that observed in shales exotic but unexceptional shales that exhibit both f ne and f xe enrichments can be produced by incomplete emptying followed by incomplete filling this mechanism is consistent with literature reported noble gas abundance patterns but may still require a separate mechanism for strong retention a system of labyrinths with constrictions and or c si nanotubes when combined with simple adsorption can result in stronger diffusive separation and non steady state enrichments that persist for longer times enhanced adsorption to multiple c atoms inside c nanotubes as well as dangling functional groups closing the ends of nanotubes can provide potential mechanisms for strong retention we need new methods of examining noble gases in rocks to determine the role and function of angstrom scale structures in both the diffusive enrichment process and the strong retention process for noble gas abundances in terrestrial rocks

determination of crustal fluid residence times using nucleogenic 39ar abstract argon 39 is a radioactive isotope of ar with a half life of 269 years there are two natural sources of 39 ar on earth cosmogenic production in the upper atmosphere and nucleogenic production in rocks cosmogenic 39 ar has been recognized as an ideal tracer for groundwater residence times and oceanic circulation nucleogenic 39 ar has generally been considered problematic for groundwater studies in this work we developed simple models for the evolution of 39 ar 40 ar ratios where 40 ar denotes radiogenic 40 ar produced in the model system in rocks and fluids in rocks both 39 ar and 40 ar are produced and a fraction of the 39 ar and 40 ar is released into the mobile fluid phase in both reservoirs 39 ar reaches production or supply decay equilibrium whereas 40 ar accumulates with time thereby the 39 ar 40 ar ratio in rocks and fluids generally decreases with time our models suggest that the co evolution of these two isotopes in rocks and fluids provides a new chronometer of fluid migration and reaction in the crust this chronometer is relevant to a much wider time range than that limited by radioactive decay of cosmogenic 39 ar i e 1400 years at the current detection limit of 3 modern atmospheric value the 39 ar 40 ar chronometer is applicable to estimating residence times of very old groundwater as well as for studying fluid rock interactions and fluid migration rates such as those occurring during co 2 sequestration and the formation of hydrocarbon reservoirs

tidal variability in the lower thermosphere comparison of whole atmosphere model wam simulations with observations from timed 1 the upper atmosphere and ionosphere exhibit variability on spatial and temporal scales characteristic of tides and planetary waves originating in the lower atmosphere to study their generation vertical propagation possible nonlinear interactions and effects a new whole atmosphere model wam has been developed as part of the integrated dynamics through earth s atmosphere idea project wam is a 150 layer general circulation model based on the us national weather service s operational global forecast system gfs model extended upward to cover the atmosphere from the ground to about 600 km first simulations reveal the presence of migrating and nonmigrating tides modulated at planetary wave periods in the upper atmosphere comparisons with observations from the timed satellite in the lower thermosphere show that wam reproduces the seasonal variability of tides remarkably well including the diurnal eastward harmonic with zonal wavenumber 3 de3 recently implicated in the observed spatial morphology of the ionosphere

ionospheric current system during sudden stratospheric warming events 1 this paper describes ionospheric current systems associated with the counter electrojet during sudden stratospheric warming ssw events in the northern winter months of 2001 2002 and 2002 2003 magnetic data from 20 stations in the east asian region covering both the northern hemisphere and the southern hemisphere are analyzed additional current systems that are superposed on the normal sq current system and related to the counter electrojet during the ssw events show a global semidiurnal current pattern which shifts to later local times approximately by 0 8 hour day the results indicate that abnormally large lunar tidal winds played a main role to produce the additional current system and counter electrojet during the ssw events

the atmospheric inventory of xenon and noble gases in shales the plastic bag experiment noble gases in five shales have been examined in the traditional protocol for trapped gas analysis and also in a new protocol in which the shales are sealed in air prior to analysis the second protocol eliminates the possibility of gas loss in the preanalysis laboratory vacuum exposure characteristic of the traditional protocol this experiment is designed to further test the shale hypothesis which stipulates that atmospheric noble gases occur in the same proportions as planetary gases in meteorites and that the factor of approximately 23 deficiency of air xe relative to planetary xe is made up by xe stored in shales or other sedimentary rocks previously available data do not support this hypothesis but could be criticized as possibly seriously underestimating shale xe contents because of experimental limitations the procedure used in this study circumvents these limitations and the results still do not support the shale hypothesis from these results it appears quite unlikely that sedimentary rocks can account for the hypothesized missing xe and unless some other atmospheric reservoir can be found to contain it it correspondingly appears that the best working hypothesis is that atmospheric noble gases are simply not planetary if so either the chemical history of the earth must account for preferential storage of xe in the earth s interior or solar nebula process responsible for noble gas incorporation in solids were significantly different for meteorites and the earth

tracer applications of noble gas radionuclides in the geosciences noble gas radionuclides including 81kr t1 2 229 000 years 85kr t1 2 10 8 years and 39ar t1 2 269 years possess nearly ideal chemical and physical properties for studies of earth and environmental processes recent advances in atom trap trace analysis atta a laser based atom counting method have enabled routine measurements of the radiokrypton isotopes as well as the demonstration of the ability to measure 39ar in environmental samples here we provide an overview of the atta technique and a survey of recent progress made in several laboratories worldwide we review the application of noble gas radionuclides in the geosciences and discuss how atta can help advance these fields specifically determination of groundwater residence times using 81kr 85kr and 39ar dating old glacial ice using 81kr and an 39ar survey of the main water masses of the oceans to study circulation pathways and estimate mean residence times other scientific questions involving a deeper circulation of fluids in the earth s crust and mantle are also within the scope of future applications we conclude that the geoscience community would greatly benefit from an atta facility dedicated to this field with instrumentation for routine measurements as well as for research on further development of atta methods

noble gases in crude oils from the paris basin france implications for the origin of fluids and constraints on oil water gas interactions in order to investigate the potential of noble gases to trace the dynamics of oil reservoirs we have analysed the abundance and isotopic composition of all noble gases he ne ar kr and xe in crude oils from the paris basin france using a new extraction and purification procedure the main oil reservoirs are presently located in the jurassic dogger limestone and in the triassic keuper sandstone but hydrocarbons originated from a common source rock formation located in the interbedded liassic sequence despite this common origin the abundance and isotopic ratios of the noble gases differ between the dogger and the keuper the isotopic compositions of kr and xe are indistinguishable from that of air 3he 4he ratios higher than those predicted from radiogenic production in the sediments or in the crust are attributed to the occurrence of mantle derived 3he in the basin each sedimentary sequence is characterised by well defined and homogeneous 21ne 22ne and 40ar 36ar ratios which average 0 0306 0 0008 and 312 10 for the dogger and 0 0367 0 0012 and 664 30 for the keuper respectively the main source of radiogenic noble gases appears to be the continental crust underlying the basin with possible regional contributions of noble gas isotopes produced in the sediments the helium and argon isotopic ratios of the dogger oils are very similar to those observed in geothermal waters flowing in the dogger aquifer throughout the basin demonstrating that noble gases in oils derive from associated groundwaters oil reservoirs in the paris basin therefore accumulate noble gases from wide regions of the continental crust through cross formational flow of groundwaters and subsequent partitioning into oil this observation implies that noble gases cannot be directly used to date oils but can provide time constraints if 1 water oil interactions are quantified and 2 the residence time as well as the noble gas characteristics of associated groundwaters are known oil water gas partitioning processes are well recorded in the fractionation of noble gas elemental abundance two distinct processes have been identified 1 accumulation of atmosphere derived ang and radiogenic noble gases both initially dissolved in groundwaters resulting in a positive correlation between absolute amount of ang and the extent of heavy noble gas fractionation and 2 subsequent fractional degassing resulting in a negative correlation between ang abundance and heavy noble gas fractionation degassing is particularly evident for the keuper oils and might have occurred in the reservoirs following hydrodynamic gas stripping the ang abundance in the dogger reservoirs requires that about one order of magnitude more water than presently observed has interacted with the oil given current estimates of the residence time for groundwaters in the dogger aquifer the duration of oil water interaction is in qualitative agreement with a palaeocene oligocene age for the major episode of secondary oil migration in the paris basin high xenon contents in keuper reservoirs suggest that they have experienced hydrodynamic interactions between flowing waters and oils for long time and that the trias might have reached hydrostatic condition only recently

long duration penetration of the interplanetary electric field to the low latitude ionosphere during the main phase of magnetic storms 1 it is well known that the interplanetary electric field can penetrate to the low latitude ionosphere it is generally believed that the penetration of electric fields can last only for 30 min because of the shielding effect in the ring current in this paper we present the observations of the dayside ionospheric electric field enhancements at middle and low latitudes in association with reorientations of the interplanetary magnetic field imf in six cases the eastward electric field in the dayside equatorial ionosphere measured by the jicamarca incoherent scatter radar was enhanced for 2 3 hours after the imf turned southward and remained continuously southward in one case the eastward electric field in the dayside midlatitude ionosphere measured by the millstone hill incoherent scatter radar was continuously enhanced for 10 hours during southward imf since millstone hill is close to the equatorward boundary of the auroral zone during magnetic storms the penetration electric field there may be different from that at the equatorial ionosphere the most striking feature of the measurements is that the enhancements of the ionospheric electric field can last for many hours without significant decay the electric field enhancements in the middle and low latitude ionosphere are closely related to magnetic activity and occur during the main phase of magnetic storms the observations show that the interplanetary electric field can continuously penetrate to the low latitude ionosphere without shielding for many hours as long as the strengthening of the magnetic activity is going on under storm conditions

degassing of mantle derived co2 and he from springs in the southern colorado plateau region neotectonic connections and implications for groundwater systems groundwaters of the southern colorado plateau arizona transition zone region are a heterogeneous mixture of chemically diverse waters including meteoric epigenic fluids karst aquifer waters and deeply sourced endogenic fluids we investigate the composition of travertine depositing co 2 rich springs to determine the origin transport and mixing of these various components the san francisco mountain recharge area has little surface flow instead waters discharge through major springs hundreds of kilometers away about 70 9340 l s of the total recharge 13 500 l s discharges 100 km to the north in the incised aquifer system at grand canyon most of this water 85 8070 l s emerges through two travertine depositing karst spring systems blue springs 6230 l s and havasu springs 1840 l s about 30 of recharge 4150 l s flows to the south and discharges along nw striking faults in the arizona transition zone forming the base flow for the verde river geochemical data define regional mixing trends between meteoric recharge and different endogenic end members that range from bicarbonate waters to sulfate waters water quality in the region is dictated by the percentage and character of the endogenic inputs that cause a measurable degradation of groundwater quality for water supply sources for the high co 2 include dissolution of limestone and dolostone c carb and external carbon c external c external is computed as the bicarbonate alkalinity dissolved inorganic carbon dic minus the c carb c external dic c carb c external is deconvolved using carbon isotopes into biogenically derived sedimentary carbon c organic and deep co 2 inputs c endogenic measured 13 c values are 17 to 3 versus pee dee belemnite pdb assuming 13 c carb 2 13 c organic 28 and 13 c endogenic 5 water chemistry mixing models indicate that an average of 42 of the total dic comes from dissolution of carbonate rocks 25 from organic carbon including soil respired co 2 and 33 from deep endogenic sources helium isotope values 3 he 4 he in gases dissolved in spring waters in the southern colorado plateau region range from 0 10 to 1 16 r a relative to air indicating that a significant component of the deeply derived fluid is from the mantle mean of 5 asthenospheric or 10 subcontinental lithospheric mantle source measured co 2 3 he ratios of 2 10 9 to 1 4 10 13 are adjusted by removing the proportion of co 2 from c carb and c organic to give values 10 for all but four samples various mixing models using co 2 3 he suggest that the mantle derived components of the co 2 load are highly variable from spring to spring and may make up an average of 10 of the total co 2 load of the regional springs fluid rock interactions involving endogenic fluids are suggested by 87 sr 86 sr 18 o and other tracers the endogenic co 2 component multiplied by discharge for each spring yields an integrated annual flux of deeply derived co 2 to the groundwater system of 1 4 10 9 mol yr this co 2 emission from the colorado plateau region reflects a complex tectonic evolution involving laramide hydration of the lithosphere above the farallon slab addition of fluids from mid tertiary mantle tectonism during slab removal and ongoing fluid movement induced by neotectonic small scale asthenospheric convection

dating ultra deep mine waters with noble gases and 36cl witwatersrand basin south africa abstract concentrations and isotopic ratios of dissolved noble gases 36cl d and 18o in water samples from the ultra deep gold mines 0 718 to 3 3 km below the surface in the witwatersrand basin south africa were investigated to quantify the dynamics of these ultra deep crustal fluids the mining activity has a significant impact on the concentrations of dissolved gases as the associated pressure release causes the degassing of the fissure water the observed under saturation of the atmospheric noble gases in the fissure water samples 70 98 normalized to asw at 20 c and 1013 mbar is reproduced by a model that considers diffusive degassing and solubility equilibration with a gas phase at sampling temperature corrections for degassing result in 4he concentrations as high as 1 55 10 1cm3stp4he g 1 40ar 36ar ranging between 806 and 10331 and 134xe 132xe and 136xe 132xe ratios above 0 46 and 0 44 respectively corrected 134 136 xe 132xe and 134 136 xe 4he ratios are consistent with their production ratios whereas the nucleogenic 4he 40ar and 134 136 xe 40ar ratios generally indicate that these gases are produced in an environment with an average u th k content 2 3 times above that of crustal average in two scenarios one considering only accumulation of in situ produced noble gases the other additionally crustal flux components the model ages for 14 individual water samples range from 13 to 168 ma and from 1 to 23 ma respectively the low 36cl ratios of 4 37 10 15 and comparatively high 36cl concentrations of 8 350 10 15 atoms 36cl l 1 reflect subsurface production in secular equilibrium indicating an age in excess of 1 5 ma or 5 times the half life of 36cl in combination the results suggest residence times of the fluids in fissures in this region up to 3 3 km depth are of the order of 1 100 ma we cannot exclude the possibility of mixing and that small quantities of younger water have been mixed with the very old bulk

fingerprinting coal derived gases from the uk abstract the large scale extraction of unconventional hydrocarbons in the united states has led to fears of methane contamination of shallow groundwaters differentiating between the deep gas released during extraction shale gas coal bed methane and underground coal gasification and natural shallow sourced methane is imperative for the monitoring and managing of environmental risks related to the extraction process here for the first time we present measurements of the major gas and stable and noble gas isotope composition of coal bed methane cbm from central scotland and coal mine methane cmm from central england uk the molecular c1 c2 c3 21 to 121 and stable isotope compositions 13cch4 39 5 to 51 1 dch4 163 to 238 indicate a thermogenic origin for the methane they are distinct from the majority of shallow sourced gases in uk both sample suites exhibit high he concentrations 338 to 2980 ppmv that are considerably above atmospheric and groundwater levels simple modelling shows that these high 4he concentrations cannot be solely derived from in situ production since coal deposition and hence the majority is derived from the surrounding crust the scottish cbm contains a resolvable mantle he ne and ar contribution that may originate from melts in the deep crust demonstrating the uk coals have acted as a store for deep volatiles for 10s of millions of years the high 4he in the coal derived gases has the potential to be used as a novel diagnostic fingerprint to track fugitive release of deep methane from future unconventional gas extraction operations in the uk

multiple atmospheric noble gas components in hydrocarbon reservoirs a study of the northwest shelf delaware basin se new mexico the northwest shelf of the delaware basin se new mexico is the site of several large and productive oil and gas fields the most productive reservoirs are located in the late pennsylvanian morrow and early permian abo formations production from the latter more important play is predominately from fluvial abo red beds of the pecos slope field the oxidizing conditions implied by the reddish color of the formation require an external hydrocarbon source to test the existing migration model for the region and constrain the location of potential hydrocarbon sources we measured the elemental and isotopic composition of noble gases produced along with the hydrocarbons we found the hydrocarbons to be highly enriched in radiogenic 4he 40 ar and nucleogenic 21 ne f 4he 44 000 250 000 40ar 36ar 400 3145 21ne 22ne 0 044 0 071 the greatest enrichments occur in the pecos slope gas fields the hydrocarbons also contain three independent nonradiogenic noble gas components each with an atmospheric isotopic composition one component is most likely air saturated water asw the second component is enriched in the heavy noble gases f 130xe 8 5 and is derived from the hydrocarbon sources the third component is enriched in ne f 20ne 0 8 that we believe is degassed from sources within the reservoirs this component is correlated with but decoupled from the dominant source of radiogenic 4he and 40 ar very high concentrations of 4he up to 1 by volume in the pecos slope reservoirs require a source external to the reservoirs such as the underlying precambrian basement granites and sedimentary equivalents structural buckles cutting through the pecos field may act as high flux vertical pathways for the radiogenic 4he if the hydrocarbons in the pecos slope fields have migrated northward from the deeper delaware basin as suggested by compositional trends then perhaps the buckles also play an important role in the distribution and filling of the pecos slope reservoirs

129i and 36cl in dilute hydrocarbon waters marine cosmogenic in situ and anthropogenic sources abstract the long lived halogen radioisotopes 129 i and 36 cl provide valuable information regarding the source of fluids in hydrocarbon systems and in localized areas where infiltration of younger meteoric water has occurred despite the utility of these two isotopes in providing time signatures for fluid end members considerable uncertainty remains regarding the interpretation of intermediate age waters in hydrologic systems these waters are likely the result of the combination of two or more halogen sources at some time in the past each with its own characteristic concentration and isotopic composition in order to unravel the evolution of these intermediate age waters the effect that infiltration of meteoric water has on the isotopic composition of older formation waters is modeled also evaluated is the effect that the timing of dilution has on 129 i and 36 cl signatures observed in the present specifically the hypothesis that halogen isotopic signatures imparted by the mixing of brine and meteoric waters early in the development of a sedimentary basin are quantitatively different from those imparted by the mixing of old brines with recent meteoric waters the modeled results are compared to previously published isotopic data from production wells in the fruitland formation coalbed methane system portions of the basin preserve enough of the original brine source to retain 129 i i ratios roughly recording the age of deposition of organic matter 73 76 ma even where some degree of dilution by meteoric water has occurred however the 129 i signatures of waters that presently contain less than 10 of the original formation water component indicate that mixing has occurred within the past 10 ma consistent with recently published 4 he data both 36 cl concentrations and 36 cl cl ratios show that waters containing more than 10 formation water are all in secular equilibrium with the host formation coals in contrast waters with less than 1 of the original formation water s cl content all have 36 cl cl ratios which are greater than secular equilibrium values indicating the migration of meteoric water into the coal formation more recently than 2 ma although 36 cl signatures in the fruitland formation are not significantly affected by anthropogenic input 129 i i ratios in a subset of samples that retain less than 1 of the initial formation water component suggest input of anthropogenic 129 i during the past 50 a

producing characteristics and depositional environments of lower pennsylvanian reservoirs parkway empire south area eddy county new mexico the parkway empire area on the northwest shelf of the permian basin about 15 mi 24 km northeast of carlsbad new mexico produces gas from stratigraphic traps within four lower pennsylvanian zones lower and middle morrow sandstones atoka sandstones and strawn limestones the lower morrow sandstones which occur at about 11 400 ft 3 470 m are interpreted to be a prograding fluvial deltaic sequence of channels and point bars with a northwest source they trend toward the southeast generally normal to the morrowan paleoslope the lower morrow sands are separated from the middle morrow sandstones by a widespread dark gray organic lagoonal shale in southeastern new mexico middle morrow sandstones are a transgressive series of marine beaches and bars deposited along the northeast trending ancient shoreline stratigraphic traps are created in the lower and middle morrow sandstones by variations in cementation and depositional patterns productive atoka sandstones occur at approximately 10 700 ft 3 260 m and appear to be a series of prograding barri r bars deposited along the northeast trending shoreline strawn limestones produce from a series of small low relief algal banks developed along northeast depositional strike the strawn limestones occur between 10 250 and 10 500 ft 3 120 and 3 200 m the area is economically attractive payout of a typical well occurs in 1 2 years with a rate of return of 78 1 pennsylvanian completions in this area have typical ultimate recoveries of approximately 1 5 bcf 42 106 m3 of gas and 22 000 bbl 3 5 106 l of condensate the stacked nature of the reservoirs causes a success rate of 85 2 for this area the high success rate good production and attractive economics make this area of the morrow trend an important exploration target

helium accumulation in groundwater ii a model for the accumulation of the crustal 4he degassing flux abstract a model of 4 he accumulation in a confined aquifer is presented which includes in situ production and a crustal degassing flux of 4 he into the bottom of a confined aquifer the model is consistent with the measurements of 4 he concentration in the great artesian basin australia torgersen and clarke 1985 and also with the measurements of 4 he concentration in the auob sandstone of namibia heaton 1981 the measured value of the crustal degassing flux of 4 he from these two areas is comparable with the 4 he degassing flux calculated from the atmospheric budget of 4 he wasserburg et al 1963 ozima and podosek 1983 a literature review suggests that a crustal degassing 4 he source may account for the 4 he accumulation in many other groundwater systems it is concluded from the literature review the detailed modelling of 4 he accumulation in gab and the auob sandstone and the atmospheric budget that crustal degassing of 4 he may be a common and widespread phenomena

leakage of magmatic hydrothermal volatiles from a crater bottom formed by a submarine eruption in 1989 at teishi knoll japan abstract a submarine eruption occurred off the izu peninsula of japan on 13 july 1989 forming teishi knoll which has a diameter of 450 m and a height of ca 10 m above the surrounding 90 100 m deep seafloor immediately after the eruption intense gas release was observed from two vents in the crater the gas bubbling gradually decreased and apparently ceased in 1990 given that no survey has been undertaken to examine volatile release from the crater of teishi knoll we collected seawater samples at three different sites from just above the crater bottom on 17 july 2012 in order to detect signs of magmatic volatile release seawater samples from the crater bottom have dissolved ch 4 contents and 13 c values higher than those of shallower 50 100 m deep seawater samples total inorganic carbon contents from the bottom seawater samples are also higher and 13 c and 14 c values lower than those of shallower seawater samples these data indicate the addition of minor ch 4 and co 2 of hydrothermal or magmatic origin to the bottom seawater from the crater 3 he 4 he ratios and total organic carbon data are also consistent with the leakage of magmatic fluids the most prominent ch 4 and co 2 anomalies were observed at the site located closest to one of the bubbling gas sites of the 1989 eruption as such volcanic gas emissions still continue today at extremely low levels 23 years after eruption of this monogenetic volcano the monitoring of ultra trace amounts of chemical components in seawater is a prospective method to monitor temporal changes in magmatic activity at such submarine volcanoes

natural gas association with water and oil as depicted by atmospheric noble gases case studies from the southeastern mediterranean coastal plain a model for the equilibrium distribution of atmospheric noble gases ang between natural gas and water phases was extended to include the gas oil relationship the basic assumption is that the ang are introduced into hydrocarbon systems via recharge or seawater theoretical ang patterns of natural gas at equilibrium with water fall between the air pattern and that of air saturated water theoretical ang patterns of natural gas degassed from oil which had previously equilibrated with a water phase cover a wide range including the range calculated for gas water equilibration ang patterns in natural gas which fall outside the overlapping range may thus indicate association of the gas with oil the model was tested in the case of hydrocarbon systems of the southeastern mediterranean coastal plain other geochemical evidence indicates that the ashdod sadot shallow gas wells are not related to oil the relative ang abundances in gas samples from these wells lie within the range predicted for gas water association the relative ang abundances in samples degassed from oils of the helez kokhav oilfield are similar to specific patterns predicted for the degassing of oil which was previously associated with water published and new analyses of methane dominated natural gas samples from california japan and northern israel also reveal ang patterns of the type predicted by the model the results of the case studies support our hypothesis that water is responsible for transport of atmospheric noble gases into subsurface hydrocarbon systems this forms the basis for identification of oil associated natural gases via ang study

connections between deep tropical clouds and the earth s ionosphere 1 we report on a series of simulations with the national center for atmospheric research ncar thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm which were designed to replicate and facilitate the interpretation of the longitudinal structure discovered in image satellite airglow observations of the equatorial ionization anomaly eia at the far ultraviolet fuv 135 6 nm wavelength during march april 2002 equinox our time gcm results indicate that the four peaked longitudinal variation in the eia observed by image fuv near 20 00 local solar time can be explained by the effects of an eastward propagating zonal wavenumber 3 diurnal tide de3 that is excited by latent heat release associated with raindrop formation in the tropical troposphere

xe in amorphous silica a new thermometer in geothermal systems we measured noble gases in amorphous silica of geothermal origin these samples were formed by precipitation from geothermal water in neutral ph and by the leaching of rocks in acid hot springs the concentration of 132xe has a negative correlation with the temperature of geothermal water although 36ar and 84kr show no such correlation the relationship between 132xe content a 10 8cm stp g and temperature t c is approximated by the equation a 4 5 10 3 t 0 50 the obtained equation should be useful for estimating the silica forming temperature that cannot be easily measured by other methods

identifying and quantifying natural co2 sequestration processes over geological timescales the jackson dome co2 deposit usa co2 sources sinks and migration mechanisms in natural co2 gas fields provide critical analogues for developing the safe application of anthropogenic co2 sequestration technologies here we use noble gas and carbon isotopes together with other gases to identify and quantify the origin transport and trapping mechanisms of co2 in the late cretaceous jackson dome co2 gas deposit 98 75 to 99 38 co2 located in central mississippi usa and producing from 5000 m it is one of the deepest commercial co2 gas fields in the world 10 gas samples from producing wells were determined for their noble gas chemical and stable carbon isotope composition he 3 he 4 ratios range between 4 27r a and 5 01r a where r a is the atmospheric value of 1 4 x 10 6 indicating a strong mantle signature similar to co2 deposits worldwide co2 he 3 decreases with increasing groundwater derived ne 20 and he 4 we model several different processes that could account for the jackson dome data and conclude that similar to other co2 dominated deposits a groundwater gas stripping and re dissolution ggs r process best accounts for observed ne 20 ar 36 kr 84 ar 36 co2 he 3 delta c 13 co2 he 4 ne 20 and ar 36 in this context crustal and magmatic co2 components contribute 57 and 43 respectively changes in co2 he 3 across the field show that groundwater contact is responsible for up to 75 loss of original emplaced co2 delta c 13 co2 variance limits the degree of precipitation to be less than 27 with the remaining co2 loss being accounted for by dissolution only a higher degree of dissolution gas loss and evidence for water contact at the reservoir crest compared to the reservoir flanks is used to argue that co2 in this system has not undergone subsequent loss to either dissolution or precipitation since shortly after reservoir filling at over 60 ma c 2012 elsevier ltd all rights reserved

external sq currents in the india siberia region the sq current systems for quiet days of 1976 and 1977 were studied for observatories established near 76 degrees e longitude in the northern hemisphere a special sperical harmonic analysis technique was used to separate the internal and external contributions of the quiet field variations and to determine the equivalent external current contours responsible for the sq field variations on the sixth and twenty first of each month the average ratio of the external to internal spectral power was 6 7 in 1976 and 7 4 in 1977 focus positions for the india siberia region external sq current vortex near 22 degrees to 29 degrees were found to be at lower geomagnetic latitudes than for europe and north america the usual mid latitude vortex current reaching 11 0 to 13 2 times 10 sup 4 a in summertime disappeared completely during winter months in both the years the sq current position was affected clearly by the off spin axis position of the north geomagnetic pole throughout the 2 years the authors also found small current vorticies near 70 degrees to 80 degrees geomagnetic latitude which have been ascribed to auroral region activity on quiet days 19 refs 11 figs 1 tab

neon excess in pumice volcanological implications abstract we measured the noble gas abundance and ne and ar isotopic compositions in pumice samples from japan and the eolian islands italy the goal was to give clues on the mechanism of air incorporation into pumice and its relationship with eruption processes the samples contain large excesses of atmospheric ne over ar with 20 ne 36 ar ratios up to 600 times the atmospheric ratio this excess is produced by the preferential diffusion of ne over ar in pumice vesicles during volcanic eruptions the 20 ne 36 ar ratios measured in pumice reflect the initial quenching temperature the cooling rate of the eruption column and the bubble s wall thickness the final ne amount is likely to be proportional to the volume of preserved vesicles in pumice calculations indicate that the fraction of isolated vesicles are less than 10 of the total suggesting that a few amount of gas is preserved in pumice after deposition

quiet variability of equatorial e b drifts during a sudden stratospheric warming event 1 we present strong evidence that during the january 2008 minor sudden stratospheric warming ssw event the equatorial vertical e b drifts exhibit a unique and distinctive daytime pattern we do not think one event causes the other however both events might be related through the global effects of planetary waves the drifts were measured by the jicamarca incoherent scatter radar located under the magnetic equator we have observed an anomalous temporal variation of the vertical e b drifts during the minor ssw event showing a semidiurnal variation with very large amplitudes lasting for several days large differences in the e b drifts were observed during a period of large increase of temperature and a large decrease of mean zonal wind in the high latitude stratosphere 60 90 n this high correlation is an unexpected finding which might shed new light on sources and mechanisms of quiet time ionospheric variability

fossil brines preserved in the st lawrence lowlands quebec canada as revealed by their chemistry and noble gas isotopes abstract brines in cambrian sandstones and ordovician dolostones of the st lawrence lowlands at becancour quebec canada were sampled for analysis of all stable noble gases in order to trace their origin and migration path in addition to quantifying their residence time major ion chemistry indicates that the brines are of na ca cl type possibly derived from halite dissolution 87 sr 86 sr ratios and ca excess indicate prolonged interactions with silicate rocks of the proterozoic grenville basement or the cambrian potsdam sandstone the brines constrain a 2 3 contribution of mantle 3 he and large amounts of nucleogenic 21 ne and 38 ar and radiogenic 4 he and 40 ar 4 he 40 ar and 21 ne 40 ar ratios corrected for mass fractionation during incomplete brine degassing are identical to their production ratios in rocks the source of salinity halite dissolution plus the occurrence of large amounts of 40 ar in brines constrain the residence time of becancour brines as being older than the cretaceous evaporites in the st lawrence lowlands likely existed only during devonian silurian time brines might result from infiltration of devonian water leaching halite penetrating into or below the deeper cambrian ordovician aquifers during the devonian the basin reached temperatures higher than 250 c allowing for thermal maturation of local gas prone source rocks utica shales and possibly facilitating the release of radiogenic 40 ar into the brines the last thermal event that could have facilitated the liberation of 40 ar into fluids and contributed to mantle 3 he is the cretaceous monteregian hills magmatic episode for residence times younger than the cretaceous it is difficult to find an appropriate source of salinity and of nucleogenic radiogenic gases to the becancour brines

numerical study of nucleation and growth of bubbles in viscous magmas the nucleation and growth processes of bubbles in viscous magmas with a constant decompression rate have been numerically investigated based on a formation which accounts for effects of viscosity as well as diffusivity interfacial tension and decompression rate the numerical solutions show two regimes in the nucleation and growth process a diffusion controlled regime and a viscosity controlled regime mainly depending on the decompression rate initial saturation pressure and viscosity the basic mechanism common to both regimes is that growth governs nucleation through depletion of degassing components in basaltic eruptions the vesiculation is essentially controlled by diffusion and the viscosity controlled regime is limited to very high decompression rate and very small water content when andesitic magma saturated by water at 10 mpa is decompressed through the propagation of rarefraction wave induced by a landslide as took place in the mount st helens 1980 eruption the vesiculation is controlled by the viscosity up to 100 m depth on the other hand in a rhyolitic magma for the same situation vesiculation is controlled by the viscosity over the whole depth of the magma column in the viscosity controlled regime the vesicularity may be 90 or less as seen in silicic pumice whereas in the diffusion controlledmore regime the vesicularity equals or exceeds 98 such as in reticulite in hawaiian basalt an observed variation of the number density of bubbles by several orders of magnitude in plinian eruptions and the correlation with the sio2 content can be attributed approximately to the dependence of diffusivity of viscosity on sio2 content and temperature assuming the apparent correlation between sio2 content and temperature of magma less

air xe enrichments in elk hills oil field gases role of water in migration and storage hydrocarbons from the elk hills naval petroleum reserve npr 1 bakersfield ca are enriched in heavy noble gases the 132xe 36ar ratios are as high as 576 times the ratio in air and represent the largest relative xe enrichments ever observed in terrestrial fluids the xe isotopic composition is indistinguishable from air we show that these samples cannot be explained by equilibration of oil with air saturated water and secondary enrichment via a rayleigh distillation gas stripping process based on laboratory studies of others with potential petroleum source rocks we believe the source of this enriched heavy noble gas component was adsorbed air initially trapped in on the source rocks that was expelled and mixed with the hydrocarbons during expulsion and primary migration kr and xe enrichments decrease with increasing 36ar concentration we propose a model in which an initial kr xe enriched hydrocarbon becomes diluted with noble gases extracted from air saturated groundwater during expulsion migration and storage the model generates an integrated water hydrocarbon ratio for the production fluid which indicates a minimal role for water in hydrocarbon expulsion and migration the results are interpreted to provide time geometrical constraints on the mechanisms by which hydrocarbons can migrate as a separate phase

basin scale natural gas source migration and trapping traced by noble gases and major elements the pakistan indus basin he ne and ar concentrations he and ar isotopic ratios carbon isotopic ratios and chemical compositions of hydrocarbon gases were measured in natural gas samples from gas producing wells in the indus basin pakistan where no oil has ever been found 3he 4he ratios are in the range 0 01 0 06 ra ra is the atmospheric value of 1 38 10 6 indicating the absence of mantle derived helium despite the trias extension 40ar 36ar ratios range from 296 to 800 consistent with variable additions of radiogenic argon to atmospheric groundwater derived argon rare gas concentrations show large variations from 6 10 5 to 1 10 3 mol mol for 4he and from 3 10 7 to 3 10 5 mol mol for 36ar in general 36ar concentrations are high compared to literature data for natural gas co2 and n2 concentrations are variable ranging up to 70 and 20 respectively mantle derived he is not observed therefore co2 and n2 are not mantle derived either hydrocarbon gas maturity is high but accumulation efficiency is small suggesting that early produced hydrocarbons including oil were lost as well as mantle helium this is consistent with the generally late pliocene trap formation and explains the high n2 concentrations since n2 is the final species generated at the end of organic matter maturation based on 13c data co2 originates from carbonate decomposition very elevated 20ne 36ar ratios are found reaching a maximum of 1 3 compared to 0 1 0 2 for air saturated water and 0 5 for air and these high values are related to the lowest rare gas concentrations we suggest that this highly fractionated signature is the trace of the past presence of oil in the basin and appeared in groundwater we propose a model where oil water contact is followed by gas water contact both with rayleigh distillation for rare gas abundance ratios thereby generating the fractionated 20ne 36ar signature in groundwater first and transferring it to gas later assuming the gas water contact occurred shallower than present reservoir depths this model explains the generally high 36ar concentrations and low ch4 36ar ratios compared to other studies on younger basins it thus provides a historical perspective on fluid transfer in a sedimentary basin where a gas accumulation may have been buried to greater depth since formation rare gas and major element data point to mixing between two gas pulses produced successively the very co2 n2 rich gases are terminal products of organic matter maturation which have been trapped after important migration this gas was followed by a more typical thermogenic gas which mixed with it

assessing compositional variability and migration of natural gas in the antrim shale in the michigan basin using noble gas geochemistry abstract this study uses stable noble gases he ne ar kr xe volume fractions and isotopic ratios from antrim shale natural gas to assess compositional variability and vertical fluid migration within this reservoir in addition to distinguishing between the presence of thermogenic versus biogenic methane r ra values where r is the measured 3he 4he ratio and ra is the atmospheric value of 1 384 0 013 10 6 vary from 0 01 to 0 34 suggesting a largely dominant crustal 4he component with minor atmospheric and mantle contributions crustal 21ne 40ar and 136xe contributions are also present but the atmospheric component is largely dominant for these gases crustal contributions for 21ne 40ar and 136xe vary between 1 1 and 12 5 between 0 7 and 19 and between 0 1 and 2 7 respectively a few samples present higher than atmospheric 20ne 22ne ratios pointing to the presence of a small mantle ne component high horizontal and vertical variability of noble gas signatures in the antrim shale are observed these are mainly due to variable noble gas input from deep brines and to a smaller extent variable in situ production within different layers of the antrim shale in particular the lachine and norwood members estimated 4he ages considering external 4he input for antrim shale water vary between 0 9 ka and 238 2 ka and match well for most samples with the timing of the major wisconsin glaciation suggesting that antrim shale water was influenced by glaciation induced recharge consistency between measured and predicted 40ar 36ar ratios assuming ar release temperatures 250 c supports a thermogenic origin for most of the methane in these samples this thermogenic methane is likely to originate at greater depths either from the deeper portion of the antrim shale in the central portion of the michigan basin or from deeper formations given that the thermal maturity of the antrim shale in the study area is rather low

noble gas tracing of groundwater coalbed methane interaction in the san juan basin usa the san juan basin natural gas field located in northwestern new mexico and southwestern colorado in the usa is a case type coalbed methane system groundwater is thought to play a key role in both biogenic methane generation and the co2 sequestration potential of coalbed systems we show here how noble gases can be used to construct a physical model that describes the interaction between the groundwater system and the produced gas we collected 28 gas samples from producing wells in the artesian overpressured high production region of the basin together with 8 gas samples from the underpressured low production zone as a control stable isotope and major species determination clearly characterize the gas in the high production region as dominantly biogenic in origin and the underpressured low producing region as having a significant admix of thermogenic coal gas 3he 4he ratios increase from 0 0836ra at the basin margin to 0 318ra towards the center indicating a clear but small mantle he signature in all gases coherent fractionation of water derived 20ne 36ar and crustal 4he 40ar are explained by a simple rayleigh fractionation model of open system groundwater degassing low 20ne concentrations compared to the model predicted values are accounted for by dilution of the groundwater associated gas by desorbed coalbed methane this rayleigh fractionation and dilution model together with the gas production history allows us to quantify the amount of water involved in gas production at each well the quantified water volumes in both underpressured and overpressured zones range from 1 7 103 m3 to 4 2 105 m3 with no clear distinction between over and underpressured production zones these results conclusively show that the volume of groundwater seen by coal does not play a role in determining the volume of methane produced by secondary biodegradation of these coalbeds there is no requirement of continuous groundwater flow for renewing the microbes or nutrient components we furthermore observe strong mass related isotopic fractionation of 20ne 22ne and 38ar 36ar isotopic ratios this can be explained by a noble gas concentration gradient in the groundwater during gas production which causes diffusive partial re equilibration of the noble gas isotopes it is important for the study of other systems in which extensive groundwater degassing may have occurred to recognize that severe isotopic fractionation of air derived noble gases can occur when such concentration gradients are established during gas production excess air derived xe and kr in our samples are shown to be related to the diluting coalbed methane and can only be accounted for if xe and kr are preferentially and volumetrically trapped within the coal matrix and released during biodegradation to form ch4

a magnus opus helium neon and argon isotopes in a north sea oilfield this study of the magnus oilfield located in the east shetland basin northern north sea represents the most detailed investigation of noble gas isotope systematics in a liquid hydrocarbon reservoir yet undertaken samples from nine producing wells across this middle jurassic field were taken and the helium neon and argon isotopic ratios and abundances in the oil were determined both the helium and the neon isotope systematics require a contribution from a mantle source if the mantle endmember is modeled using mid ocean ridge mor values 2 3 4 5 of the 4he and 4 3 6 2 of the 21ne is mantle derived the remainder of the 4he and 9 0 12 0 of the 21ne is crustal radiogenic and the remaining 21ne is atmosphere derived the resolved mantle derived he ne ratio is quite distinct from upper mantle values estimated from mor samples but indistinguishable from values resolved in other regions of continental extension this result provides strong evidence that the subcontinental lithospheric mantle not only has a different noble gas inventory to the convecting mantle under mors but also has a near uniform composition the quantity of radiogenic noble gas associated with the magnus oil groundwater system can only be accounted for by production predominantly from outside the volume of the magnus sandstone aquifer reservoir drainage area and the associated kimmeridge clay source rock formation and together with the mantle derived noble gases provides strong evidence for cross formational communication with deeper regions of the crust the 20ne and 36ar must have been input into the oil phase by interaction with an air equilibrated groundwater noble gas partitioning between a seawater derived groundwater and the oil phase at the average magnus sandstone aquifer temperature requires a subsurface seawater oil volume ratio of 110 40 to account for both the 20ne and 36ar concentrations in the central and southern magnus samples the volume of groundwater which has equilibrated with the magnus oil is indistinguishable from the static volume of water estimated to be in the down dip magnus aquifer reservoir drainage volume this suggests that the magnus oil has obtained complete equilibrium with the groundwater in the reservoir drainage volume probably during secondary migration and further suggests that concurrent cementation of the magnus sandstone aquifer has occurred with little or no large scale movement of air equilibrated groundwater through the aquifer system higher concentrations of 20ne and 36ar in the n magnus oil cannot be accounted for by equilibration with a seawater derived groundwater this is qualitatively consistent with the earlier and more mature oil in this section equilibrating with freshwater which is known to have been trapped in the crest of the reservoir structure

noble gas and methane partitioning from ground water an aid to natural gas exploration and reservoir evaluation the partitioning of noble gases and methane from oil field brines can provide valuable information about the redistribution of gas phase constituents the alterations in fluid compositions produced by closed system phase changes are predictable with pronounced differences from original compositions if these alterations commonly occur in sedimentary basins then a new aid for natural gas exploration and reservoir evaluation can be developed

halogens and noble gases in sedimentary formation waters and zn pb deposits a case study from the lennard shelf australia abstract halogen ratios br cl and i cl and concentrations provide important information about how sedimentary formation waters acquire their salinity but the possible influence of organic br derived from sedimentary wall rocks is rarely quantified here it is demonstrated that br cl versus i cl mixing diagrams can be used to deconvolve organic br contributions that organic matter has a limited range of br i ratios and that organic br is a more significant component in zn pb deposit ore fluids than previously recognised the significance of these findings is illustrated for the lennard shelf zn pb deposits of western australia fluid inclusions related to lennard shelf zn pb mineralisation have variable salinity and hydrocarbon contents the halogen data from these fluid inclusions require mixing of three fluid end members 1 an evaporated seawater bittern brine 30 wt nacl equiv with greater than seawater br cl ratio 2 a lower salinity pore fluid 5 wt nacl equiv with moderately elevated br cl and i cl and 3 fluids with br cl ratios of 5 times seawater and extremely elevated i cl ratios of 11 500 times seawater the first two fluids have 40 ar 36 ar of 300 400 and greater than air saturated water 36 ar concentrations that are typical of fluid inclusions related to zn pb mineralisation the third organic rich fluid has the highest 40 ar 36 ar ratio of up to 1500 and a depleted 36 ar concentration mineralisation is interpreted to have resulted from mixing of zn rich evaporitic brines and h 2 s present in hydrocarbons it is suggested that aqueous fluids acquired organic br and i from hydrocarbons and that hydrocarbons exsolving from the aqueous fluid removed noble gases from solution interaction of variably saline brines and hydrocarbons could account for the variable br cl and i cl composition and 36 ar concentrations recorded by lennard shelf fluid inclusions the distinct 40 ar 36 ar signature of the fluid with the highest i cl ratio suggests the hydrocarbons and brines were sourced independently from different parts of the sedimentary basin these data indicate the complementary nature of halogen and noble gas analysis and provide new constraints on important mixing processes during sediment hosted zn pb mineralisation

helium isotopes in the izu peninsula japan relation of magma and crustal activity abstract the relation of magma and crustal activity has been studied from spatial distribution of 3he 4he ratios of gas and or water samples over the izu peninsula where significant crustal deformation associated with seismic swarm activities has been observed since 1970s the air corrected values of 3he 4he ratios ranged from 3 5 to 8 2 ra where ra is the atmospheric 3he 4he ratio 1 4 10 6 indicating that helium is mostly of magmatic origin among the three pressure sources proposed to explain the crustal deformation two inflation sources beneath the inland of northeast and the mid east coast of the izu peninsula locate in the broad distribution of high 3he 4he ratios which supports relation of magma to the crustal uplift in contrast the distribution of 3he 4he ratios around the tensile fault assumed in the area of seismic swarms appears not to indicate existence of significant amount of magma below the tensile fault alternatively the results suggest magma below a point several kilometers south of the tensile fault the seismic swarms are explained either by fluid pressurization of thermal water heated by this magma or by intrusion of magma to the tensile fault moved obliquely from the deep magma reservoir

magma degassing process during plinian eruptions abstract to assess magma degassing processes during plinian eruption noble gas abundances and isotopic ratios have been determined in pumices by crushing under vacuum samples come from plinian eruptions which occur along different subduction zones in addition two pumice samples come from the azores hotspot all samples are characterized by a systematic enrichment in neon over argon a depletion of krypton relative to argon and an isotopically fractioned 38 ar 36 ar ratio these features do not depend on geological setting or on pumice age or eruption intensity however they are similar for pumices from the same eruption a correlation is observed between 84 kr 36 ar and the 38 ar 36 ar ratio this illustrates that only one physical process is at the origin of the fractionation we propose here a model of kinetic magma degassing before fragmentation to explain the elemental and isotopic fractionation noble gases diffuse in a magma shell surrounding a preexisting bubble the model put forward an alternative to the model of pinti et al 1999 in which diffusion occurs after pumice quenching in plinian plume the model explains measurements and shows the rapidity of the magma degassing process in the conduit few hundreds of seconds

longitudinal variation of ionospheric vertical drifts during the 2009 sudden stratospheric warming 1 the whole atmospheric model wam initialized with a data assimilation scheme is capable of simulating real sudden stratospheric warming ssw events the electrodynamics in the coupled thermosphere ionosphere and plasmasphere with electrodynamics model ctipe was driven by the wam thermospheric winds in january 2009 to study the response of ionospheric drifts during the ssw simulation results are compared with observations of the vertical drift at jicamarca and the equatorial electrojet eej in the asian sectors early morning upward drift and afternoon downward drift are reproduced in all longitudes in the simulations and are consistent with the available observations results also show that the occurrence time of the early morning upward drift and afternoon downward drift have significant phase differences between different longitudes simulations suggest that during the ssw the longitude dependence of the amplitude and phase of the equatorial vertical plasma drift is caused by the changing magnitudes of the migrating tides modulated by the geometry of the geomagnetic field some additional day to day variability and modulation of the phase structures at different longitudes in ionospheric vertical drifts during the ssw are possibly produced by the short term changes in the non migrating tides and by planetary waves

origin of hydrocarbon and noble gases carbon dioxide and molecular nitrogen in the miocene strata of the eastern part of the polish carpathian foredeep isotopic and geological approach abstract fifteen natural gas samples were collected from the autochthonous miocene strata between debica and przemy l towns in the eastern sector of the polish carpathian foredeep the samples were analysed for the molecular and stable isotope compositions of carbon 13c in ch4 c2h6 c3h8 i c4h10 n c4h10 and co2 hydrogen 2h in ch4 c2h6 and c3h8 nitrogen 15n in n2 and all stable isotopes of noble gases he ne ar kr and xe in order to reveal the origin and migration pathway of these gases methane concentrations usually exceeded 90 vol methane was mainly generated by microbial carbon dioxide reduction the rhythmic and cyclic deposition of clays muds and sands in the miocene marine basin facilitated and intensified microbial processes microbial ethane can be produced by methanogenic archaea from acetate via reduction ethane partly contains a minor component generated from early mature thermogenic process propane and butanes were also generated thermogenically the hydrocarbon gases in the miocene horizons iia and iiia of the gora ropczycka field were generated at higher maturity thermogenic process than the rest of the analysed miocene gases probably from the middle jurassic type iii kerogen they migrated to the miocene horizons from the underlying upper jurassic horizon iv of the same field along a fault carbon dioxide of the analysed miocene gases was mainly generated by primary microbial processes moreover the total carbon constrained in the analysed miocene gases from 0 1 to 6 wt contained mantle derived carbon and thus carbon dioxide mantle component molecular nitrogen was mainly generated during low temperature thermal transformation of organic matter it might also involve a relatively insignificant component released from nh4 rich illites of the clayey facies of miocene strata and an atmospheric component delivered by recharge of air saturated seawater to the reservoir inorganic fluid supply from greater lithospheric depth would not be responsible for the promotion of thermal transformation of organic matter molecular nitrogen from miocene horizons in the gora ropczycka field was generated during the thermal transformation of organic matter of higher maturity than the rest of miocene gases and migrated from the upper jurassic horizon along a fault helium is dominated by its radiogenic component with a minor contribution from the mantle the almost constant mixing ratios of the two helium components in the natural gases from miocene horizons of various depths suggest that he migrated from a common inorganic deep seated source in the lithosphere the other noble gases are dominated by atmospheric components delivered to the hydrocarbon reservoirs by recharge of air saturated seawater with minor nucleogenic 21ne radiogenic 40ar and sedimentary kr and xe contributions the atmospheric component is isotopically fractionated for ne and elementally fractionated with various degrees the ratios of radiogenic 4he to nucleogenic 21ne or radiogenic 40ar are higher than the crustal production ratios suggesting fractionation during thermal release from their host minerals and or phase related fractionation during their transport to the gas reservoirs the striking similarity in noble gas isotopic elemental ratios of the gora ropczycka gas from the miocene horizon iiia to the nearby reservoir in mesozoic strata is consistent with gas migration along a fault system

radar and satellite global equatorial f region vertical drift model we present the first global empirical model for the quiet time f region equatorial vertical drifts based on combined incoherent scatter radar observations at jicamarca and ion drift meter observations on board the atmospheric explorer e satellite this analytical model based on products of cubic b splines and with nearly conservative electric fields describes the diurnal and seasonal variations of the equatorial vertical drifts for a continuous range of all longitudes and solar flux values our results indicate that during solar minimum the evening prereversal velocity enhancement exhibits only small longitudinal variations during equinox with amplitudes of about 15 20 m s is observed only in the american sector during december solstice with amplitudes of about 5 10 m s and is absent at all longitudes during june solstice the solar minimum evening reversal times are fairly independent of longitude except during december solstice during solar maximum the evening upward vertical drifts and reversal times exhibit large longitudinal variations particularly during the solstices in this case for a solar flux index of 180 the june solstice evening peak drifts maximize in the pacific region with drift amplitudes of up to 35 m s whereas the december solstice velocities maximize in the american sector with comparable magnitudes the equinoctial peak velocities vary between about 35 and 45 m s the morning reversal times and the daytime drifts exhibit only small variations with the phase of the solar cycle the daytime drifts have largest amplitudes between about 0900 and 1100 lt with typical values of 25 30 m s we also show that our model results are in good agreement with other equatorial ground based observations over india brazil and kwajalein

mantle helium in sacramento basin natural gas wells abstract helium isotope ratios in sacramento basin natural gas wells show a strong mantle signal the3he 4he ratios range from 0 11 times the atmospheric ratio 0 11 ra in the rio vista field to 2 75 ra in the moon bend field indicating that 1 to 34 of the helium is mantle derived 3he 4he versus ch4 4he ratios provide evidence of two component mixing between crustal and magmatic end members extrapolation of the linear regression line to ch4 4he 0 gives a hypothetical magmatic end member 3he 4he ratio of 3 84 ra half the typical mantle ratio this indicates that the magmatic end member may actually represent a mixture of mantle and crustal helium gases which deviate from the simple two component mixture can be explained by addition of pure methane radiogenic 4he or a high n2 he component with 3he 4he 0 6 ra to 1 0 ra the ch4 3he ratio of the magmatic end member remains poorly constrained 0 to 3 109 and one cannot rule out the possibility that a significant proportion of the methane in some fields may be of deep earth origin however fields with the highest 3he 4he ratios are associated with buried plio pleistocene intrusives which have up arched sediments to form hydrocarbon traps the methane in these fields may have been produced by rapid thermal alteration of the intruded sediment elsewhere the methane appears either to have migrated from deeply buried sediments in the western basin or to have been produced by local microbial activity

vesicle connectivity in pyroclasts and implications for the fluidisation of fountain collapse pyroclastic flows montserrat west indies abstract pyroclastic flows are noted for their highly mobile behaviour being able to flow on slopes as low as a few degrees and this has been attributed to fluidisation or partial fluidisation by escaping gases the three types of pyroclastic flows generated during the eruption of soufriere hills volcano on montserrat dome collapse fountain collapse and surge derived differ in their apparent mobility suggesting different degrees of fluidisation and friction reduction in the flowing granular materials several possible sources of fluidising gas operate in pyroclastic flows the purpose of this paper is to assess the feasibility of one mechanism the release during flow of pressurised gases trapped in the vesicles of juvenile clasts measurements with a helium pycnometer show that all vesicles in dense lava blocks from dome collapse pyroclastic flows are connected so that the mechanism is probably not viable for such flows on the other hand pumices from fountain collapse pyroclastic flows from soufriere hills and other volcanoes contain up to 10 vol of isolated vesicles this is confirmed by sem imagery which shows that soufriere hills pumices contain two vesicle populations with a bimodal size distribution the large vesicles are mostly interconnected whereas about two thirds of the smaller population

noble gases solubility models of hydrocarbon charge mechanism in the sleipner vest gas field abstract noble gases are chemically inert and variably soluble in crustal fluids they are primarily introduced into hydrocarbon reservoirs through exchange with formation waters and can be used to assess migration pathways and mechanisms as well as reservoir storage conditions of particular interest is the role groundwater plays in hydrocarbon transport which is reflected in hydrocarbon water volume ratios here we present compositional stable isotope and noble gas isotope and abundance data from the sleipner vest field in the norwegian north sea sleipner vest gases are generated from primary cracking of kerogen and the thermal cracking of oil gas was emplaced into the sleipner vest from the south and subsequently migrated to the east filling and spilling into the sleipner ost fields gases principally consist of hydrocarbons 83 93 co2 5 4 15 3 and n2 0 6 0 9 as well as trace concentrations of noble gases helium isotopes 3he 4he are predominantly radiogenic and range from 0 065 to 0 116 ra reported relative to air ra 1 4 10 6 clarke et al 1976 sano et al 1988 showing predominantly 98 crustal contributions consistent with ne 20ne 22ne from 9 70 to 9 91 21ne 22ne from 0 0290 to 0 0344 and ar isotopes 40ar 36ar from 315 to 489 air derived noble gas isotopes 20ne 36ar 84kr 132xe are introduced into the hydrocarbon system by direct exchange with air saturated water asw the distribution of air derived noble gas species are controlled by phase partitioning processes in that they preferentially partition into the gas i e methane phase due to their low solubilities in fluids therefore the extent of exchange between hydrocarbon phases and formation waters that have previously equilibrated with the atmosphere can be determined by investigating air derived noble gas species we utilize both elemental ratios to address process i e open vs closed system and concentrations to quantify the extent of hydrocarbon water exchange i e volumetric gas water ratios these data are discussed within the framework of several conceptual models i total gas stripping model which assumes all noble gases have been stripped from the water phase thus defining the minimum volume of water to have interacted with the hydrocarbon phase ii equilibrium model which assumes equilibration between groundwater and hydrocarbon phase at reservoir p t and salinity and iii open and closed system gas stripping models using concentrations and elemental ratios by applying these models to ne ar data from sleipner we estimate volumetric gas water ratios v g v w between 0 02 and 0 07 which are lower than standard geologic gas water estimates of 0 24 estimated by combining gas in place estimates with groundwater porosity estimates sleipner vest data can be best approximated by an open system model which predicts more than an order of magnitude more groundwater interaction during migration than geologic estimates indicating a dynamic aquifer system and or a hydrous migration pathway in an open system the extent of gas loss can be estimated to be between 8 and 10 reservoir volumes which have passed through the system and been lost i e filled and spilled

the noble gas geochemistry of natural co2 gas reservoirs from the colorado plateau and rocky mountain provinces usa identification of the source of co2 in natural reservoirs and development of physical models to account for the migration and interaction of this co2 with the groundwater is essential for developing a quantitative understanding of the long term storage potential of co2 in the subsurface we present the results of 57 noble gas determinations in co2 rich fields 82 from three natural reservoirs to the east of the colorado plateau uplift province usa bravo dome nm sheep mountain co and mccallum dome co and from two reservoirs from within the uplift area st john s dome az and mcelmo dome co we demonstrate that all fields have co2 3he ratios consistent with a dominantly magmatic source the most recent volcanics in the province date from 8 to 10 ka and are associated with the bravo dome field the oldest magmatic activity dates from 42 to 70 ma and is associated with the mcelmo dome field located in the tectonically stable centre of the colorado plateau co2 can be stored within the subsurface on a millennia timescale the manner and extent of contact of the co2 phase with the groundwater system is a critical parameter in using these systems as natural analogues for geological storage of anthropogenic co2 we show that coherent fractionation of groundwater 20ne 36ar with crustal radiogenic noble gases 4he 21ne 40ar is explained by a two stage re dissolution model stage 1 magmatic co2 injection into the groundwater system strips dissolved air derived noble gases asw and accumulated crustal radiogenic noble gas by co2 water phase partitioning the co2 containing the groundwater stripped gases provides the first reservoir fluid charge subsequent charges of co2 provide no more asw or crustal noble gases and serve only to dilute the original asw and crustal noble gas rich co2 reservoir scale preservation of concentration gradients in asw derived noble gases thus provide co2 filling direction this is seen in the bravo dome and st john s dome fields stage 2 the noble gases re dissolve into any available gas stripped groundwater this is modeled as a rayleigh distillation process and enables us to quantify for each sample 1 the volume of groundwater originally stripped on reservoir filling and 2 the volume of groundwater involved in subsequent interaction the original water volume that is gas stripped varies from as low as 0 0005 cm3 groundwater cm3 gas stp in one bravo dome sample to 2 56 cm3 groundwater cm3 gas stp in a st john s dome sample subsequent gas groundwater equilibration varies within all fields each showing a similar range from zero to 100 cm3 water cm3 gas at reservoir pressure and temperature

hydrogeochemistry of the middle rio grande aquifer system fluid mixing and salinization of the rio grande due to fault inputs abstract deeply derived fluids influence river and groundwater hydrochemistry at the socorro constriction in the central new mexico rio grande rift new hydrochemical transects in the rio grande rift provide three dimensional perspectives on sources contributing to surface and groundwaters in addition to abrupt salinity increases in the rio grande major and trace ion chemistry 18o d 13c 87sr 86sr 3h and 3he 4he variations in springs and wells across the rift are best explained by mixing of deeply derived endogenic fluids containing both mantle and crustal inputs with shallow groundwater endogenic fluids ascend along rift bounding and intra rift faults and can cause increased salinity accompanied by an increase in metals and overall degradation of water quality our data reinforce models that attribute a downstream increase in salinity to geological not agricultural influences hydrochemical mixing of endogenic waters along faults in shallow aquifers has a major influence on groundwater and surface water quality and variability in arid tectonically active regions with important ramifications for water management

origin of hydrocarbon and noble gases carbon dioxide and molecular nitrogen in devonian pennsylvanian and miocene strata of the polish lublin and ukrainian lviv basins southern part of the upper silesian coal basin and western part of the carpathian foredeep poland abstract sixteen natural gas samples were collected from devonian pennsylvanian and miocene strata of the polish lublin and ukrainian lviv basins from the southern area of the upper silesian coal basin uscb and western part of the carpathian foredeep cf in poland the samples were analysed for the molecular composition and stable isotope compositions of gaseous hydrocarbons ch4 c2h6 and c3h8 and co2 n2 and noble gases he ne ar kr and xe in order to reveal the origin and migration pathways of these gases hydrocarbon gases and the majority of the of co2 were generated during two stages of thermogenic processes from type ii and ii iii kerogens in the lublin basin and during both thermogenic and microbial processes in the lviv basin the thermogenic component was generated from type ii kerogen coal bed hydrocarbon gases accumulated in the pennsylvanian strata of the southern part of the uscb originated from both thermogenic and microbial processes isotopically light microbial methane may have migrated from miocene upper badenian skawina formation of the cf to carboniferous coal bearing strata and or might result from diffusion and adsorption desorption processes during the migration of thermogenic gases from deeper lying coal seams through the microporous coal structure hydrocarbon gases and carbon dioxide which accumulated in the sandstone reservoirs of upper badenian skawina formation of the western part of the cf most probably were generated from dispersed organic matter within the claystones and mudstones of these strata and at least partly migrated from the carboniferous coal bearing strata of the uscb n2 could have been produced as a result of various biogenic and abiogenic processes and contributed to the atmospheric component characteristic radiogenic 4he composition of the analysed gases suggest the accumulation of particles formed from u and th radioactive decay in the crustal gas reservoirs radiogenic 40ar and nucleogenic 21ne with abundance ratios characteristic of crustal reservoirs were also observed addition of mantle derived he to the gases from miocene strata is evident from elevated 3he 4he ratios ranging between 0 2 and 1 6 10 6 a small contribution of ne from the mantle along with he is also suggested by the slightly elevated 20ne 22ne ratios relative to atmosphere the mantle component is most likely to have migrated from the upper mantle to the gas reservoirs through the deep seated bzie czechowice fault zone

the noble gas isotope record of hydrocarbon field formation time scales abstract noble gases may be considered as the most prominent tracers of natural fluids including hydrocarbons the atmosphere is the only source of 20ne 36ar 84kr 130xe in subsurface environments and their concentrations in pore waters after recharge are known from the solubility data this allows modelling of noble gas partitioning between coexisting gas oil and water phases in the course of hydrocarbon formation migration and storage radiogenic isotopes 4he 21ne 40ar 136xe after being released from source rocks are mixed with air derived noble gases already present in the pore space concentrations of radiogenic species in the pore space of typical hydrocarbon fields are generally so high that they can hardly be accumulated in situ and thus indicate noble gas transfer from ground waters the time bearing ratios 4he 20ne 21ne 20ne 4he 40arair 40ar 40arair in hydrocarbon fields are thus proportional to the time interval between the ground water recharge and noble gases partitioning into the hydrocarbon phase s the recharge partition interval the largest available data set allows the recharge partition intervals to be constrained for a large number of hydrocarbon fields situated in different tectonic settings ancient plates young plates mobile belts these intervals increase systematically with the ages of hydrocarbon source and trap lithologies and are comparable with these ages this important feature valid in general for different hydrocarbon fields implies i local sources of radiogenic noble gas isotopes in ground waters ii relatively recent formation of hydrocarbon fields and iii their short formation time scales in some cases the duration of formation of a hydrocarbon field can be constrained for example nearly constant 21ne 20ne 40ar 40arair ratios measured in samples from the magnus oil field north sea give an accumulation time scale 10 ma it should be emphasized that the above noble gas isotope ratios give the time estimates which are independent of geological reconstructions sometimes the noble gas inventory in a hydrocarbon field and ground waters allows characterization of the source rock volume involved in formation of the field generally this volume exceeds that of the hydrocarbon field rocks by orders of magnitude

noble gases fingerprint a metasedimentary fluid source in the macraes orogenic gold deposit new zealand the world class macraes orogenic gold deposit 10 moz resource formed during the late metamorphic uplift of a metasedimentary schist belt in southern new zealand mineralising fluids metals and metalloids were derived from within the metasedimentary host helium and argon extracted from fluid inclusions in sulphide mineral grains three crush extractions from one sample have crustal signatures with no evidence for mantle input r ra 0 03 xenon extracted from mineralised quartz samples provides evidence for extensive interaction between fluid and maturing organic material within the metasedimentary host rocks with 132xe 36ar ratios up to 200 times greater than air similarly i cl ratios for fluids extracted from mineralised quartz are similar to those of brines from marine sediments that have interacted with organic matter and are ten times higher than typical magmatic mantle fluids the macraes mineralising fluids were compositionally variable reflecting either mixing of two different crustal fluids in the metasedimentary pile or a single fluid type that has had varying degrees of interaction with the host metasediments evidence for additional input of meteoric water is equivocal but minor meteoric incursion cannot be discounted the macraes deposit formed in a metasedimentary belt without associated coeval magmatism and therefore represents a purely crustal metamorphogenic end member in a spectrum of orogenic hydrothermal processes that can include magmatic and or mantle fluid input elsewhere in the world there is no evidence for involvement of minor intercalated metabasic rocks in the macraes mineralising system hydrothermal fluids that formed other smaller orogenic deposits in the same metamorphic belt have less pronounced noble gas and halogen evidence for crustal fluid rock interaction than at macraes but these deposits also formed from broadly similar metamorphogenic processes

behavior of the quiet day ionospheric current system in the european region the ionospheric current system for magnetic quiet days deduced from geomagnetic field daily variations taken throughout europe at sunspot minimum has been studied special attention was paid to the selection of the representative quiet days showing the inadequacy of relying on the mean of the five international quiet days per month we used the technique of spherical cap harmonic analysis to separate the external and internal parts of the field variation from which the derivation of the equivalent current functions is straightforward this method provides a motion picture representation of the sq system through the screen formed by the spherical cap allowing the study of continuous variations with universal time detailed features of the current contours can be represented with such a regional analysis we found a strong day to day variability of the focus position along with some complexities that differ from the standard sq current behavior the average monthly or seasonal patterns are therefore averages of heterogeneous behaviors in many occasions possible explanations to these complex structures are considered

ionospheric current system associated with the equatorial counterelectrojet the phenomenon of the equatorial counterelectrojet current cej is studied utilizing the d h and z components of the magnetic field at a chain of geomagnetic observatories in the indo russian zone extending from 0 to 75 n magnetic dip very significant changes in both h and d components are shown to occur on cej days at all stations even north of sq focus the current system associated with cej consists of two vortices one counterclockwise in the morning and another clockwise in the evening hours the counterelectrojet events during december solstices seem to be associated with the disappearance of the sq current loop in the indo russian sector and on a number of consecutive days the cause of the counterelectrojet is suggested to be the changes in various modes of the tidal movements in the upper atmosphere