the salinity temperature and δ18o of the glacial deep ocean we use pore fluid measurements of the chloride concentration and the oxygen isotopic composition from ocean drilling program cores to reconstruct salinity and temperature of the deep ocean during the last glacial maximum lgm our data show that the temperatures of the deep pacific southern and atlantic oceans during the lgm were relatively homogeneous and within error of the freezing point of seawater at the ocean s surface our chloride data show that the glacial stratification was dominated by salinity variations in contrast with the modern ocean for which temperature plays a primary role during the lgm the southern ocean contained the saltiest water in the deep ocean this reversal of the modern salinity contrast between the north and south atlantic implies that the freshwater budget at the poles must have been quite different a strict conversion of mean salinity at the lgm to equivalent sea level change yields a value in excess of 140 meters however the storage of fresh water in ice shelves and or groundwater reserves implies that glacial salinity is a poor predictor of mean sea level

bioassay for estimating the biogenic methane generating potential of coal samples abstract generation of secondary biogenic methane in coal beds is likely controlled by a combination of factors such as the bioavailability of coal carbon the presence of a microbial community to convert coal carbon to methane and an environment supporting microbial growth and methanogenesis a set of treatments and controls was developed to bioassay the bioavailability of coal for conversion to methane under defined laboratory conditions treatments included adding a well characterized consortium of bacteria and methanogens enriched from modern wetland sediments and providing conditions to support endemic microbial activity the contribution of desorbed methane in the bioassays was determined in treatments with bromoethane sulfonic acid an inhibitor of microbial methanogenesis the bioassay compared 16 subbituminous coal samples collected from beds in texas tx wyoming wy and alaska ak and two bituminous coal samples from pennsylvania pa new biogenic methane was observed in several samples of subbituminous coal with the microbial consortium added but endemic activity was less commonly observed the highest methane generation 80 mol methane g coal 56 scf ton or 1 75 cm 3 g was from a south tx coal sample that was collected from a non gas producing well subbituminous coals from the powder river basin wy and north slope borough ak contained more sorbed original methane than the tx coal sample and generated 0 23 mol g up to 16 scf ton or 0 5 cm 3 g new biogenic methane in the bioassay standard indicators of thermal maturity such as burial depth nitrogen content and calorific value did not explain differences in biogenic methane among subbituminous coal samples no original methane was observed in two bituminous samples from pa nor was any new methane generated in bioassays of these samples the bioassay offers a new tool for assessing the potential of coal for biogenic methane generation and provides a platform for studying the mechanisms involved in this economically important activity

chemistry isotopic composition and origin of a methane hydrogen sulfide hydrate at the cascadia subduction zone abstract although the presence of extensive gas hydrate on the cascadia margin offshore from the western u s and canada has been inferred from marine seismic records and pore water chemistry solid gas hydrate has only been found at one location at ocean drilling program odp site 892 offshore from central oregon gas hydrate was recovered close to the sediment water interface at 2 19 m below the seafloor mbsf at 670 m water depth the gas hydrate occurs as elongated platy crystals or crystal aggregates mostly disseminated irregularly with higher concentrations occurring in discrete zones thin layers and or veinlets parallel or oblique to the bedding a 2 to 3 cm thick massive gas hydrate layer parallel to bedding was recovered at 17 mbsf gas from a sample of this layer was composed of both ch4 and h2s this sample is the first mixed gas hydrate of ch4 h2s documented in odp it also contains ethane and minor amounts of co2 measured temperatures of the recovered core ranged from 2 to 1 8 c and are 6 to 8 degrees lower than in situ temperatures these temperature anomalies were caused by the partial dissociation of the ch4 h2s hydrate during recovery without a pressure core sampler during this dissociation toxic levels of h2s 34s 27 4 were released the 13c values of the ch4 in the gas hydrate 64 5 to 67 5 pdb together with d values of 197 to 199 smow indicate a primarily microbial source for the ch4 the 18o value of the hydrate h2o is 2 9 smow comparable with the experimental fractionation factor for sea ice the unusual composition ch4 h2s and depth distribution 2 19 mbsf of this gas hydrate indicate mixing between a methane rich fluid with a pore fluid enriched in sulfide at this site the former is advecting along an inclined fault into the active sulfate reduction zone the facts that the ch4 h2s hydrate is primarily confined to the present day active sulfate reduction zone 2 19 mbsf and that from here down to the bsr depth 19 68 mbsf the gas hydrate inferred to exist is a 99 ch4 hydrate suggest that the mixing of ch4 and h2s is a geologically young process because the existence of a mixed ch4 h2s hydrate is indicative of moderate to intense advection of a methane rich fluid into a near surface active sulfate reduction zone tectonically active faulted margins with organic rich sediments and moderate to high sedimentation rates are the most likely regions of occurrence the extension of such a mixed hydrate below the sulfate reduction zone should reflect the time span of methane advection into the sulfate reduction zone

new data on the stratigraphy and pedology of the clovis and plainview sites southern high plains abstract the well known clovis and plainview archaeological sites of new mexico and texas have yielded new data on regional late quaternary geologic paleoclimatic and pedologic histories eolian sedimentation at the clovis site from about 10 000 to less than 8500 yr b p was followed by the formation of a cumulic soil between 8500 and 5000 yr b p episodic eolian and slope wash deposition then culminated in massive eolian sedimentation about 5000 yr b p after which a haplustalf formed then was subsequently buried by part of a dune system within the last 1000 yr at the plainview site a basal stream gravel contains plainview cultural material ca 10 000 yr b p which is followed by a localized early holocene lacustrine deposit two eolian deposits the younger dating to about 5000 yr b p and a marsh deposit which slowly accreted as an argiustoll formed in the younger eolian unit the data indicate that on the southern high plains 1 between 12 000 and 8500 yr b p sedimentation varied from site to site 2 there was a regional climate change toward warming and drying in the early holocene 3 two episodes of severe drought apparently occurred in the middle holocene 6500 to 4500 yr b p 4 between 4500 yr b p and the present an essentially modern climate existed but with several shifts toward aridity within the last 1000 yr 5 argillic horizons have developed in late holocene soils 6 clay illuviation can occur in calcareous soils and 7 long distance correlation of holocene stratigraphy in the region is possible particularly with the aid of soil morphology

permeability evolution during the formation of gas hydrates in marine sediments 1 fluxes of gas energy and fluid water with dissolved gas are known to control the distribution of gas hydrate and free gas in gas hydrate reservoirs but theoretical studies have so far not focused on the effect of sediment properties e g permeability on these fluxes during the formation of gas hydrate deposits using a transient one dimensional two phase gas hydrate and fluid numerical model based on a coupled conservation approach we examine permeability clogging during gas hydrate formation in end member porous media and fractures initially lacking hydrate and determine the resulting changes in fluid and advective energy flux gas hydrate accumulates most rapidly at depth in both systems a result consistent with borehole logging and seismic studies on the blake ridge consideration of the ratio of surface area to fluid volume explains model results that imply more rapid permeability reduction in the porous media system and more uniform hydrate formation as a function of depth in the fracture system depending on fluid flux fracture aperture or pore sizes and other factors the timescale for permeability clogging due to the accumulation of gas hydrate ranges from thousands to millions of years regenerating gas hydrate to a concentration of 10 15 of pore space in marine settings with fluid fluxes characteristic of hydrate ridge or blake ridge requires 103 105 years meaning that hydrate deposits in these settings cannot be viewed as a naturally renewable resource these results also imply that significant time is required to reestablish gas hydrate deposits after large scale dissociation events associated with global scale climate change

methane contents and coal rank variability in the upper silesian coal basin poland abstract the process of coalification results in changes in both the chemical composition and physical properties of the coal one of the most important stages in the development of bituminous coal is the so called second coalification jump corresponding to medium volatile coals characterized by a significant decrease of volatile matter from 33 to 20 and the release of methane carbon dioxide and water in the upper silesian coal basin uscb the highest values of methane content 12 14 m 3 t coal daf range from 35 22 v daf and vitrinite reflectance r r values from 0 84 1 50 range in approximate accord with values defining the second coalification jump v daf 29 r r 1 3 i e coking coals in the basin the distribution of the top of high methane zone 4 5 m 3 t coal daf is similar to that of the coking coals that is why increasing methane contents towards the southern and western parts of the basin can be explained by the increasing proportion of coking coals there however on a basin scale correlations between present methane contents and individual parameters of coal rank are weak due most likely to late gas migration due in turn to factors unrelated to earlier coalification including inter alia tectonic disturbance and hydrodynamic processes

micromorphological investigations of the late quaternary loess paleosol sequences of the kashmir valley india abstract the loess paleosol sequences of the karewa group preserve a valuable repository of the late quaternary climatic changes and the landscape evolution history of the karewa basin of kashmir valley in their lithological and pedogenic records three representative loess paleosol sections at shankerpora sp khan sahib ks and pattan pt localities were chosen for detailed lithostratigraphic fieldwork and micromorphological observations of thin sections lithostratigraphic analysis revealed lateral and vertical variation in thickness and number of paleosol profiles from south west to north west of the karewa basin suggesting the availability of land surface for periodic loess deposition the sp section is marked by 6 sp s6 s7 s8 s9 s10 s12 ks section by 3 ks s2 s4 s5 and pt section by 2 pt s1 s3 thick mature paleosol profiles theses paleosols have well developed ah and btk horizons representing prolonged land surface stability when pedogenic processes outpace loess deposition on the other hand comparatively thin to thick paleosol profiles represent weak to moderate pedogenic maturity indicating short stratigraphic breaks with rapid loess deposition micromorphological observations of thin sections suggested that clay illuviation and caco3 accumulation have operated within the paleosol profiles caco3 features are often associated with clay coatings suggesting decalcification of carbonates followed by clay illuviation pedogenic caco3 probably resulted from the precipitation of the soil solution near the average depth of wetting front the pedogenic caco3 illuvial clay mottles iron manganese features pedal microstructure and blocky aggregates reveal variation in the pedogenic maturity among and within the loess paleosol sections the morphological both micro and macro morphological attributes of loess paleosols suggest variation of climatic conditions during the late quaternary period in the karewa basin of kashmir valley india

massive vein filling gas hydrate relation to ongoing gas migration from the deep subsurface in the gulf of mexico abstract a gas hydrate mound that contains massive vein filling structure ii gas hydrate occurs on the upper continental slope 540 m water depth of the gulf of mexico southwest of the mississippi delta the mound is located in the green canyon gc block 185 adjacent to jolliet field in gc 184 jolliet field contains oil and gas that filled fault traps caused by salt deformation during late pleistocene holocene time in contrast to reservoir oil in jolliet field which shows bacterial oxidation effects the c 1 c 5 reservoir gas is unaltered by bacterial oxidation disassociated gas is assumed to have recently entered from the subsurface hydrocarbon system vertical migration of gas along faults is ongoing manifested on the sea floor by gas vents gas hydrate complex chemosynthetic communities and by a large gas plume that extends from the vents to the sea surface the isotopic properties of c 1 c 5 hydrocarbons from reservoirs gas vents and gas hydrate correlate closely although outcropping gas hydrate is transiently stable because of variations in seawater temperature the bulk of buried gas hydrate at gc 185 is stable and perhaps increasing in volume because of the copious gas flux the massive accumulation of gas hydrate at the gc 185 site is attributed to the gas that has recently entered the vents largely from jolliet field and to the synchronous activation of fault conduits allowing gas migration to the sea floor synchronous late gas charge and faulting could also explain the wide distribution of gas hydrate across the upper gulf slope

methanotrophic activity in carboniferous coalbed rocks abstract carboniferous coalbed rocks originating from the lublin coal basin south east poland were investigated for the presence and activity of aerobic methanotrophic bacteria laboratory studies of samples collected from 914 to 1004 m below earth s surface and performed at 30 c 100 water capacity whc and 10 v v headspace ch 4 revealed microbial methane oxidation which ranged from 0 13 to 0 75 m ch 4 g 1 day 1 methanotrophic activity ma was also investigated as a function of temperature 5 30 c moisture content 25 200 whc and substrate concentration 1 30 v v ch 4 the highest ma was recorded at 30 c 100 whc and 20 ch 4 v v indicating the mesophilic and microaerophilic character of methanotrophic bacteria mb present in the coalbed lack of detectable ma at 5 and 10 c shows narrow temperature tolerance of mb which may result from a long term isolation of the bacterial habitat and stability of thermal conditions in the coalbed cryo sem revealed presence in the investigated rocks of bacteria c a 2 2 5 m long and 0 5 1 m wide and spore like structures 0 5 1 m in diameter these observations were confirmed by fluorescence in situ hybridization with probes mg705 5 fluoresceine mg84 5 cy3 and ma450 5 cy5 which showed that enrichments in nms medium contain types i and ii mb of similar size identification performed with the use of dna amplification of 16s rrna targeted group specific primers confirmed the presence of bacteria belonging to methylosinus methylomicrobium methylocystis and methylocaldum here we show that coalbed rocks constitute a habitat for diverse mb

geopressured shale and sealing effect of smectite to illite transition ten shale samples of frio and vicksburg tertiary overpressured shales from brazoria and hidalgo counties texas were examined by transmission electron microscopy tem techniques initially illite and smectite with some mixed layer component are present in subparallel domains with smectite packets dominating and providing abundant dislocations for ion transport supplying avenues that contribute to local permeability as the transition proceeds illite packets grow within a shrinking matrix of smectite dislocations decrease and pathways for ion transport are restricted we suggest this development of illite packets and diminished ion transport causes loss of local permeability and a rise in the fluid pressure gradient as illite packets coalesce local permeabil ty is increasingly lost hydraulic continuity with the surface is further restricted and a more efficient geopressure seal is formed in both hidalgo and brazoria counties the base of normal hydropressure 0 465 psi ft or 10 5 kpa m coincides with the depth of onset of the smectite to illite transition geopressure greater than 0 7 psi ft 15 8 kpa m occurs at depths corresponding to 50 illite packets in brazoria county and 70 in hidalgo county in both cases 0 7 psi ft 15 8 kpa m geopressure occurs prior to the depth at which the transition ceases these relationships suggest that if the smectite to illite transition begins and proceeds to completion the development of coalescing illite packets during diagenesis will lead to increasing geopressure with the actual values of illite proportion and corresponding fluid pressure gradient determined by the local geologic setting

changes in the vertical structure of the north atlantic ocean between glacial and modern times the distribution of planktic foraminiferal 18o over the north atlantic ocean has been interpreted by duplessy et al 1991 1992 in terms of the distribution of surface water salinity during the last glacial maximum lgm and the younger dryas yd we present here the implications of this surface salinity distribution for changes in deep convection during these periods temperature salinity density diagrams of the water column have been constructed using the plancktic and benthic foraminifera 18o values together with sea surface temperature estimates obtained by using micropaleontological transfer functions the precision of these reconstructions is limited by the remaining uncertainties in the two basic assumptions upon which the methods are based the sea surface temperature reconstruction by climap are valid within the statistical uncertainties the water salinity 18o relationship is well constrained for surface and intermediate ocean waters a significant difference between the modern and the reconstructed glacial water structure is observed during the lgm the modern relatively warm and salty norwegian sea surface water and the north atlantic deep water nadw were replaced by low salinity surface water in the northern atlantic ocean and the norwegian sea and cold deep water 0 1 c however surface water salinity in the central north atlantic ocean 52 54 n 25 40 w was sufficiently high to permit deep water convection as a source of north atlantic intermediate and deep waters open ocean convection at the northern limit of the subtropical surface waters around 40 n may have contributed to the ventilation of the intermediate waters the waters deeper than 2000 m were the result of mixing between poorly oxygenated southern waters and well ventilated north atlantic deep waters a similar reconstruction for the cold yd period indicates that the modern type of circulation with warm and ventilated nadw was largely in operation and that the hydrologic pattern was different from that prevailing during the lgm

stratigraphy and geochronology of upper quaternary eolian sand on the southern high plains of texas and new mexico united states eolian sand in dune fields and sand sheets cover 10 000 km 2 10 of the southern high plains of northwestern texas and eastern new mexico these deposits are concentrated in three west east trending belts of dunes the muleshoe lea yoakum and andrews dune fields from north to south that appear to be eastern extensions of the mescalero monahans dune system in the pecos river valley and in the seminole sand sheet a discontinuous accumulation of sheet sands between the lea yoakum and monahans andrews dunes the most common landforms are parabolic dunes associated with blowouts coppice dunes and sand sheets all typical of sandy vegetated semiarid landscapes barchan dunes in keeping with a relatively limited sand supply and an underlying surface that is relatively hard blackwater draw formation pleistocene and fence row dunes historic dunes formed along field boundaries these eolian deposits accumulated episodically in the late pleistocene and holocene and provide clues to the history of regional drought and aridity the earliest phase of sedimentation occurred when sheet sands were deposited between 11 000 and 8000 14 c yr b p probably in several phases based on archaeological data as a result of episodic drought beginning between 11 000 and 10 000 yr b p eolian deposits dating between 8000 and 3000 yr b p are rare although eolian sediment 8000 4500 14 c yr b p is ubiquitous in the draws that cross the region and paleoenvironmental indicators show that the region was subjected to aridity throughout middle holocene time the middle holocene deposits most likely were remobilized in late holocene time most of the deposits and landforms of the dune fields and sand sheets are late holocene dating before 4000 14 c yr b p and mostly before 1500 14 c yr b p the muleshoe and lea yoakum dunes and the seminole sand sheet underwent substantial eastward expansion in late holocene time buried soils and radiocarbon ages show that the eolian sand accumulated in several stages probably in response to cyclic drought the muleshoe dunes accumulated after ca 1300 cal yr b p ca 1400 14 c yr b p after ca 750 670 cal yr b p ca 850 750 14 c yr b p just after ca 500 cal yr b p ca 450 14 c yr b p and during the nineteenth and twentieth centuries the lea yoakum dunes were active after ca 3400 cal yr b p ca 3200 14 c yr b p and historically the seminole sand sheet was active ca 430 330 cal yr b p ca 360 14 c yr b p and in the twentieth century the andrews dunes were subjected to at least two phases of eolian sedimentation after ca 2320 cal yr b p ca 2320 14 c yr b p comparisons with eolian chronologies from other regions on the great plains suggest that dune mobilization was a regional phenomenon after ca 2300 cal yr b p ca 2300 14 c yr b p after ca 1500 1400 cal yr b p ca 1650 1550 14 c yr b p after ca 700 cal yr b p ca 800 14 c yr b p between 500 and 300 cal yr b p ca 450 300 14 c yr b p and in the nineteenth century the climatic fluctuations responsible for mobilizing the dunes probably were relatively minor yet the landscape impacts were substantial resulting in widespread wind erosion and dune construction

origin of natural waters and gases within the upper carboniferous coal bearing and autochthonous miocene strata in south western part of the upper silesian coal basin poland abstract the molecular and stable isotope compositions of coalbed gases from the upper carboniferous strata and natural gases accumulated within the autochthonous upper miocene skawina formation of the debowiec simoradz gas deposit were determined as well as the chemical and stable isotope compositions of waters from the skawina formation and waters at the top of the upper carboniferous strata of the kaczyce ridge the abandoned morcinek coal mine in the south western part of the upper silesian coal basin two genetic types of natural gases within the upper carboniferous coal bearing strata were identified thermogenic ch4 small amounts of higher gaseous hydrocarbons and co2 and microbial ch4 very small amounts of ethane and co2 thermogenic gases were generated during the bituminous stage of coalification and completed at the end of the variscan orogeny degassing desorption of thermogenic gases began at the end of late carboniferous until the late miocene time period and extended to the present day this process took place in the upper carboniferous strata up to a depth of about 550 m under the sealing upper miocene cover a primary accumulation zone of indigenous thermogenic gases is present below the degassing zone up to 200 m depth from the top of the upper carboniferous strata within the weathered complex an accumulation zone of secondary microbial gas occurs waters within these strata are mainly of meteoric origin of the infiltration period just before the last sea transgression in the late miocene and partly of marine origin having migrated from the upper miocene strata then both methanogenic archaebacteria and their nutrients were transported by meteoric water into the near surface carboniferous strata where the generated microbial ch4 saturated coal seams waters within the miocene strata of the debowiec simoradz and zablocie are of marine origin and natural gases accumulated within autochthonous miocene strata of the debowiec simoradz gas deposit were most probably generated by microbial processes of on organic matter dispersed within the strata though some contribution of gases migrating from the carboniferous coal bearing strata cannot be excluded

the micromorphology of younger dryas aged black mats from nevada arizona texas and new mexico abstract black mats are organic rich sediments and soils that form in wet environments associated with spring discharge micromorphological and geochemical analyses of 25 black mats dating to the younger dryas chronozone 12 9 11 7 ka and early holocene were conducted to determine their composition and depositional environment samples were collected from arizona new mexico texas and nevada micromorphological analyses were conducted on thin sections using polarized and blue fluorescent light these analyses determined that black mats contain humic acids fine 5 20 m plant fragments diatoms phytoliths and gastropods the dominant type of organic matter in black mats is derived from herbaceous plants contradicting previous studies that supported algal or charcoal sources differences in the micromorphological characteristics of the samples revealed that black mats formed as three different types organic horizons moist soils and ponded sediments depending on their topographic position in relation to the water table the microscopic evidence found in black mats supports the presence of widespread wet environments in nevada and arizona during the younger dryas chronozone clearly indicating a sustained period of greater effective moisture optimal for spring discharge and black mat formation

origin of bottom simulating reflectors geophysical evidence from the cascadia accretionary prism vertical seismic profile vsp data from two drill sites on the cascadia margin show low velocity zones indicative of free gas be neath a bottom simulating reflector bsr offshore oregon at ocean drilling program odp site 892 velocities drop from an average of 1750 m s above the bsr to less than 1250 m s below it sonic logs confirm that seismic velocity in the sediments adjacent to the borehole is less than that of water for at least 50 m beneath the depth of the bsr at this site similarly at odp site 889 offshore vancouver velocities range from 1700 to 1900 m s in the 100 m above the bsr and drop abruptly to 1520 m s in the 15 m just beneath it the low velocities observed beneath the bsr are strong evidence for the presence of 1 5 free gas by volume the bsr at these two sites results from the contact between gas free sediments containing a small quantity of hydrate above the bsr and a low velocity free gas zone beneath it although the bsr is associated with the base of the hydrate stability field hydrate appears to account for relatively little of the velocity contrast that produces the bsr velocity above the bsr at site 889 is only about 100 m s greater than that expected for sediments of similar porosity sediments above the bsr at site 892 appear to have normal velocity for their porosity and may contain little hydrate

lubbock lake late quaternary cultural and environmental change on the southern high plains usa lubbock lake southern high plains of texas contains a cultural faunal and floral record within a virtually complete geological record spanning the past 11 100 years more than 88 archaeological occurrences have been excavated from five major stratigraphic units the paleoindian record 11 500 6500yr bp begins with clovis age occupation ca 11 100yr bp found within fluvial deposits stratum 1 subsequent paleoindian occupations are found in lake and marsh sediments stratum 2 archaic occupations 8500 2000yr bp are contained within aeolian and marsh deposits strata 3 and 4 ceramic occupations 2000 500yr bp are found on a soil developed in stratum 4 in marsh sediments strata 4 and 5 and in slopewash and aeolian sediments stratum 5 the protohistoric 500 300yr bp and historic 300 100yr bp remains are in slopewash aeolian and marsh sediments stratum 5 and associated soils the southern high plains remained a grasslands throughout the last 11 500 years and neither man nor bison abandoned the region the successive local faunas reflect changing ecosystems under pluvial to arid to more mesic to semiarid conditions the occupation of lubbock lake through time appears to have been by small groups of people for both economic and short term residential uses these hunter gatherer peoples underwent adaptive change brought about by climatic stress and alterations to food resources

the occurrence of a secondary zone of coal bed methane in the southern part of the upper silesian coal basin southern poland potential for methane exploitation abstract coal bed methane cbm exploitation in the upper silesian coal basin has in spite of earlier failures again aroused investor interest carboniferous coal seams at depths of 200 500 m are characterized by coal permeability values estimated at 27 230 md and degrees of methane saturation almost 100 that suggest future successful exploitation based on the results of geological surveys archived in the polish geological institute the shallow cbm zone is defined as a gas horizon distinct from a deep cbm zone the disposition of the shallow zone follows the topography of the upper carboniferous paleorelief and is deemed the most important factor controlling methane distribution within this zone the most favorable places for cbm accumulation within the shallow coal seams are erosional highs and the slopes of upper carboniferous ridges associated with fault zones the thickness of the zone 200 m and methane contents 8 m 3 t coal daf are highest in these places the nearly full saturation of the coal seams with methane reflects the involvement of two genetic types of gas indigenous late stage microbial methane and thermogenic methane derived from the deeper coals the favorable geological characteristic of this shallow cbm zone is a potential source of energy for upper silesia

gas hydrate systems at hydrate ridge offshore oregon inferred from molecular and isotopic properties of hydrate bound and void gases abstract we report and discuss molecular and isotopic properties of hydrate bound gases from 55 samples and void gases from 494 samples collected during ocean drilling program odp leg 204 at hydrate ridge offshore oregon gas hydrates appear to crystallize in sediments from two end member gas sources deep allochthonous and in situ as mixtures of different proportions in an area of high gas flux at the southern summit of the ridge sites 1248 1250 shallow 0 40 m below the seafloor mbsf gas hydrates are composed of mainly allochthonous mixed microbial and thermogenic methane and a small portion of thermogenic c2 gases which migrated vertically and laterally from as deep as 2 to 2 5 km depths in contrast deep 50 105 mbsf gas hydrates at the southern summit sites 1248 and 1250 and on the flanks of the ridge sites 1244 1247 crystallize mainly from microbial methane and ethane generated dominantly in situ a small contribution of allochthonous gas may also be present at sites where geologic and tectonic settings favor focused vertical gas migration from greater depth e g sites 1244 and 1245 non hydrocarbon gases such as co2 and h2s are not abundant in sampled hydrates the new gas geochemical data are inconsistent with earlier models suggesting that seafloor gas hydrates at hydrate ridge formed from gas derived from decomposition of deeper and older gas hydrates gas hydrate formation at the southern summit is explained by a model in which gas migrated from deep sediments and perhaps was trapped by a gas hydrate seal at the base of the gas hydrate stability zone ghsz free gas migrated into the ghsz when the overpressure in gas column exceeded sealing capacity of overlaying sediments and precipitated as gas hydrate mainly within shallow sediments the mushroom like 3d shape of gas hydrate accumulation at the summit is possibly defined by the gas diffusion aureole surrounding the main migration conduit the decrease of gas solubility in shallow sediment and refocusing of gas by carbonate and gas hydrate seals near the seafloor to the crest of the local anticline structure

clay illuviation in calcareous soils of the semiarid part of the indo gangetic plains india abstract in view of diverse understanding on the movement and accumulation of clay particles in calcareous parent material a micromorphological study on 28 alfisols of the semiarid part of the indo gangetic plains igp was undertaken the study indicates that the identified clay pedofeatures are typically of the type impure clay pedofeatures which have resulted from the impairment of the parallel orientation of the clay platelets induced by dispersion of both clay and silt size layer silicates in slightly to highly sodic environment the study also indicates that the illuviation of clay particles and their subsequent accumulation in the bt horizons have occurred in sodic environment caused by the precipitation of soluble ca 2 ions as calcium carbonate caco 3 thus discounting any role of soluble ca 2 ions and the presence of caco 3 in preventing the movement and accumulation of clay particles the study thus suggests that the formation of impure clay pedofeatures and pedogenic caco 3 are two pedogenic processes occurring simultaneously in soils of the igp as contemporary pedogenic events in the semiarid climate since the last 4000 years b p

middle holocene drought on the southern high plains abstract the climate of the southern high plains during the middle holocene is indicated by data from a variety of sources stratigraphic geomorphic and pedologic research at six localities in draws several dune sites and one playa lake basin show that widespread eolian erosion and sedimentation began in some areas by 9000 yr b p and culminated 6000 4500 yr b p probably because of warmer drier conditions that reduced the vegetative cover archaeological investigations at three sites provide evidence for the excavation of wells at this time apparently because of a declining water table studies of a few vertebrate and invertebrate faunas also indicate warming and drying in the middle holocene climate models and very limited isotopic data from bison bone suggest that summers in the middle holocene were warmer than present with reduced effective precipitation all lines of evidence indicate that the southern high plains was subjected to prolonged drought in the middle holocene with a maximum between 6500 and 4500 yr b p conforming climatically and chronologically to the altithermal

microbial carbon cycling in oligotrophic regional aquifers near the tono uranium mine japan as inferred from δ13c and δ14c values of in situ phospholipid fatty acids and carbon sources abstract microorganisms are ubiquitous in deep subsurface environments but their role in the global carbon cycle is not well understood the natural abundance 13c and 14c values of microbial membrane phospholipid fatty acids plfas were measured and used to assess the carbon sources of bacteria in sedimentary and granitic groundwaters sampled from three boreholes in the vicinity of the tono uranium mine gifu japan sample storage experiments were performed and drill waters analyzed to characterize potential sources of microbial contamination the most abundant plfa structures in all waters sampled were 16 0 16 1 7c cy17 0 and 18 1 7c a plfa biomarker for type ii methanotrophs 18 1 8c comprised 3 and 18 of total plfas in anoxic sedimentary and granitic waters respectively sampled from the kna 6 borehole the presence of this biomarker was unexpected given that type ii methanotrophs are considered obligate aerobes however a bacterium that grows aerobically with ch4 as the sole energy source and which also produces 56 of its total plfas as 18 1 8c was isolated from both waters providing additional evidence for the presence of type ii methanotrophs the 14c values determined for type ii methanotroph plfas in the sedimentary 861 and granite 867 waters were very similar to the 14c values of dissolved inorganic carbon dic in each water 850 this suggests that type ii methanotrophs ultimately derive all their carbon from inorganic sources whether directly from dic and or from ch4 produced by the reduction of dic in contrast 13c values of type ii plfas in the sedimentary 93 and granite 60 waters indicate that these organisms use different carbon assimilation schemes in each environment despite very similar 13 c ch 4 values 95 for each water the 13cplfa values 28 to 45 of non methanotrophic bacteria in the kna 6 ltl water do not clearly distinguish between heterotrophic and autotrophic metabolisms but 14cplfa values indicate that 65 of total bacteria filtered from the kna 6 ltl water are heterotrophs ancient 14c values 1000 of some plfas suggest that many heterotrophs utilize ancient organic matter perhaps from lignite seams within the sedimentary rocks the more negative range of 13cplfa values determined for the kna 6 granitic water 42 to 66 are likely the result of a microbial ecosystem dominated by chemolithoautotrophy perhaps fuelled by abiogenic h2 results of sample storage experiments showed substantial shifts in microbial community composition and 13cplfa values as much as 5 during 2 4 days of dark refrigerated aseptic storage however water samples collected and immediately filtered back in the lab from freshly drilled msb 2 borehole appeared to maintain the same relative relationships between 13cplfa values for sedimentary and granitic host rocks as observed for samples directly filtered under artesian flow from the kna 6 borehole of the tono uranium mine

composition and origin of coalbed gases in the upper silesian and lublin basins poland abstract coalbed gases in the upper silesian coal basin uscb are highly variable in molecular and stable isotope composition geochemical indices and stable isotope ratios for coalbed gases from uscb vary within the following ranges ch4 c2h6 c3h8 hydrocarbon index from 122 to more than 10 000 cdmi carbon dioxide methane index cdmi co2 co2 ch4 100 from 0 0 to 21 0 13c ch4 from 79 9 to 44 5 d ch4 from 202 to 153 13c c2h6 from 24 6 to 22 3 13c c3h8 24 7 one sample and 13c co2 from 27 2 to 2 8 only two coalbed gases were collected from the lublin coal basin lcb geochemical indices and stable isotope ratios for these samples show the following values hydrocarbon index more than 10 000 cdmi 4 3 and 34 6 13c ch4 67 3 and 52 5 d ch4 201 one sample and 13c co2 13 7 and 11 9 methane higher gaseous hydrocarbons c2 to c5 and carbon dioxide occurring in the coalbed gases in both the uscb and the lcb were generated during the bituminous stage of the coalification process and probably during microbial reduction of carbon dioxide however depth related isotopic fractionation which has resulted from physical e g diffusion and adsorption desorption processes during gas migration cannot be neglected in both basins the coalification process lasted no longer than several ma and was completed at the end of the variscan orogeny at the turn of carboniferous and permian

seismic character of bottom simulating reflectors examples from the mid norwegian margin three classes of bottom simulating reflectors bsr cross cut the post breakup sediments of the mid norwegian margin the first class is caused by free gas at the base of the pressure and temperature dependent gas hydrate stability zone the second class of bsr is caused by the diagenetic transition from opal a to opal ct the third class of bsr is always observed underneath the opal a opal ct transition but heat flow data and the amplitude characteristics of this arrival exclude one of the known silicate diagenetic transitions or gas hydrates as the explanation for this reflector odp site 643 drilling results from the voring plateau suggest two possible processes as the reason for this third bsr a smectite illite conversion or b a sudden increase in the abundance of authigenic carbonates the genesis of both is pressure and temperature dependent and could potentially result in a cross cutting seismic reflector the data are not conclusive as to which process is causing the third class of observed bsr

a review of the geochemistry of methane in natural gas hydrate the largest accumulations on earth of natural gas are in the form of gas hydrate found mainly offshore in outer continental margin sediment and to a lesser extent in polar regions commonly associated with permafrost measurements of hydrocarbon gas compositions and of carbon isotopic compositions of methane from natural gas hydrate samples collected in subaquatic settings from around the world suggest that methane guest molecules in the water clathrate structures are mainly derived by the microbial reduction of co2 from sedimentary organic matter typically these hydrocarbon gases are composed of 99 methane with carbon isotopic compositions 13cpdb ranging from 57 to 73 in only two regions the gulf of mexico and the caspian sea has mainly thermogenic methane been found in gas hydrate there hydrocarbon gases have methane contents ranging from 21 to 97 with 13c values ranging from 29 to 57 at a few locations where the gas hydrate contains a mixture of microbial and thermal methane microbial methane is always dominant continental gas hydrate identified in alaska and russia also has hydrocarbon gases composed of 99 methane with carbon isotopic compositions ranging from 41 to 49 these gas hydrate deposits also contain a mixture of microbial and thermal methane with thermal methane likely to be dominant published by elsevier science ltd

accumulation of coal bed methane in the south west part of the upper silesian coal basin southern poland abstract the archives of the polish geological institute house a wealth of coal bed methane cbm data from surface boreholes and excavations in coal from the deposits of the upper silesian coal basin uscb these data support a model for the origin of substantial methane accumulations in the south west part of the basin that reflects the interplay of the factors controlling methane sorption capacity and those controlling methane content the factors controlling the sorption capacity of coal include coal rank temperature pressure moisture content and maceral composition methane content controls include lithology stratigraphy tectonics hydrogeology and mining activity the nature of the coal bearing carboniferous horizons the sorption desorption properties of the coals the disposition of faults and folds the topography of the carboniferous palaeosurface and the presence of an impermeable miocene cover were key controls the methane accumulated in coal seams and in their host rocks in settings comparable with those in which petroleum and gas deposits are trapped

climatic implications of alternating clay and carbonate formation in semiarid soils of south central montana abstract evidence for climatic change is found in petrographic thin sections from soils formed on glaciofluvial deposits of rock creek and the lower clarks fork montana these soils presently in a semiarid climate range from late pliocene to holocene in age and have undergone periodic fluctuations in soil moisture caused by climatic changes in the lower parts of soil b horizons accretion of illuvial layers of clay argillans occurs mainly during wet glacial climatic periods whereas carbonate precipitates mainly during dry interglacial climatic periods thin section studies of the argillan and carbonate layers show that 1 post pinedale soils that have formed only in the present interglacial climate contain areas of secondary carbonate unrelated to argillans 2 soils formed on outwash of successively older glaciations contain proportionately more alternating layers of argillans and carbonate and 3 the maximum number and sequence of layers in a soil correspond to the number of local cycles of glacial outwash deposition and subsequent stream incision that followed the beginning of soil formation these cycles are inferred to correspond to local glacial interglacial fluctuations the correspondence between the microscopic record and the glacial outwash record for rock creek suggests that some of the climatic changes seen in the marine oxygen isotope record did not strongly affect the study area

ammonium concentration and nitrogen isotope composition in metasedimentary rocks from different tectonometamorphic units of the european variscan belt the content and isotopic composition of ammonium nh4 were measured by using kjeldahl distillation for 63 samples of predominantly metasedimentary rocks from two different geological settings of the european variscides i e the erzgebirge and the zone of erbendorf vohenstrauss in germany the studied erzgebirge schists represent an early paleozoic passive margin sequence that reappears in different deep subducted metamorphic units this allows an efficient examination of nitrogen loss and isotope fractionation during prograde metamorphism ammonium is found to be progressively depleted accompanied by a shift in 15n from the low grade units 2 kbar 300 c with 638 124 ppm and 15n 2 2 0 6 to the garnet phyllite unit 9 kbar 470 c with 621 190 ppm and 15n 3 5 0 9 the mica schist eclogite unit 12 kbar 550 c with 394 113 ppm and 15n 3 9 0 8 and to the gneiss eclogite unit 12 kbar 730 c with 99 32 ppm and 15n 7 7 2 0 using equilibrium models for rayleigh distillation and batch volatilization suggest that the nitrogen depletion took place by ammonia release only for the mica schists this isotope fractionation can be explained by the loss of molecular nitrogen in comparison with the early paleozoic schists the proterozoic ortho and paragneisses of the erzgebirge gneiss unit 6 8 kbar 650 c contain significantly lower amounts of ammonium 70 ppm and reach relatively low 15n values 2 5 to 3 6 the paragneisses from the zone of erbendorf vohenstrauss zev sampled from the ktb pilot hole represents a separate tectonometamorphic unit that has undergone polyphase metamorphic conditions with the major imprint being amphibolite facies 7 kbar 650 700 c the metagraywackes have nh4 contents of 80 ppm and 15n of approximately 6 gneisses in the vicinity of a late cataclastic shear zone at 2000 m depth are characterized by a shift in nh4 250 ppm and 15n up to 12 which suggest late fluid rock interactions with a nitrogen and 15n enriched fluid

soils and landscape evolution of eolian plains the southern high plains of texas and new mexico holliday v t 1990 soils and landscape evolution of eolian plains the southern high plains of texas and new mexico in p l k knuepfer and l d mcfadden editors soils and landscape evolution geomorphology 3 489 515 sheets of eolian sediment cover many areas of the earth s surface sand seas dune fields and loess sheets being the best known examples of such features less well known are deposits of sandy eolian sediment forming extensive plains an excellent example of such a region is the semi arid southern high plains northwest texas and eastern new mexico the level landscape of the area was created by depositon of multiple extensive 80 000 km 2 sheets of eolian sediment biackwater draw formation over the past 1 4 ma this deposit grades from sandy southwest to silty and clayey northeast and is up to 27 m thick surface soils at least 30 000 and possibly 120 000 years old are well developed 5yr hues agrillic horizons 1 2 m thick with prismatic structure stage ii iii calcic horizons and are generally paleustolls and paleustalfs with some paleargids and haplargids morphologic variation is due mainly to textural variation of the eolian parent material although locally thickness of the parent material and wind erosion and cumulization are important factors and locally slight variation in effective precipitation may be significant the blackwater draw formation contains as many as six well developed buried soils each formed in individual layers of eolian sediment similar to or more strongly expressed 2 syr hues higher illuvial clay content than the regional surface soils the presence of the buried soils indicates that sedimentation was episodic and separated by long periods of relative landscape stability eolian processes also appear to have been important during the periods of stability and pedogenesis by providing clayey calcareous dust that was added to the soil promoting formation of the argillic and calcic horizons the sedimentologic and pedologic uniformity of the deposit suggests that the regional environment has not varied significantly during the quaternary except for periods of increased sedimentation or wind deflation underlying the blackwater draw formation is an upper tertiary deposit up to 36 m thick of eolian sand silt and clay ogallala formation this deposit contains buried soils very similar to those in the blackwater draw formation suggesting that the geomorphic processes that created the quaternary landscape of the southern high plains began to operate in the late tertiary perhaps as much as 11 million years ago

multiple bottom simulating reflections in the black sea potential proxies of past climate conditions abstract a previously unknown pattern of multiple bottom simulating reflections bsrs occurs on high resolution reflection seismic data in the danube deep sea fan associated with acoustic features indicating free gas our study provides evidence that this pattern is developed in relation with the architecture of distinct channel levee systems of the danube fan channel levee systems hosting multiple bsrs act as relatively sealed gas bearing systems whose top is situated above the base of the gas hydrate stability zone bghsz inside these systems free gas accumulates below the bghsz under a combined lithological structural and stratigraphical control the uppermost bsr marks the current equilibrium bghsz for a gas composition of more than 99 methane model derived depths of the bghsz for different gas compositions and pressure temperature conditions show that multiple bsrs would correspond to the bghsz either for 1 layers of gas hydrates with high contents of heavy hydrocarbons or hydrogen sulphide or 2 stable climatic episodes with temperatures between glacial values and the present day conditions as the gas hydrate compositions required by hypothesis 1 are in sharp contradiction with the general background of the gas composition in the study area we suggest that multiple bsrs are most probably relics of former positions of the bghsz corresponding to successive steps of climate warming in this case they can provide sea bottom paleotemperature values for these episodes and hence they are potential new proxies for deciphering past climate conditions

morphology and post chaudian late pleistocene evolution of the submarine danube fan complex the danube deep sea fan in the northwestem black sea has a lateral dimension of over 150 km and stretches from several hundred metres water depth down to the abyssal plain eight seismic sequences have been recognized in the fan complex each sequence consists of channel levee and overbank deposits as well as mass transport units the danube and the ukrainian rivers have aggraded two surficial channel levee systems which diverge and decrease in volume downfan the channels of these systems have a low sinuosity implying young age steep gradients and or limited sediment supply significant channel migration occurred in the course of fan development which could be largely controlled by relative sea level changes the six youngest sequences mapped have been correlated to sea level fluctuations from the post chaudian regression to the present day

upward shifts in the southern hydrate ridge gas hydrate stability zone following postglacial warming offshore oregon 1 high resolution three dimensional 3 d seismic reflection data acquired on the r v thomas g thompson in 2000 reveal a pair of bottom simulating reflections bsrs across a broad region of southern hydrate ridge offshore oregon the primary bsr bsrp is a regionally extensive reflection that lies 120 150 m below seafloor and exhibits typical characteristics of a gas hydrate bsr we also imaged a second weaker bsr bsrs 20 40 m below bsrp with similar characteristics bsrs is interpreted as a remnant of a bsr that probably formed during the last glacial maximum 18 000 years ago when the base of the gas hydrate stability zone ghsz was deeper an increase in bottom water temperatures of 1 75 2 25 and a corresponding sea level rise of 120 m could have produced the bsr shift the preservation of bsrs for at least 5000 years which is the time since subseafloor temperatures stabilized following ocean warming after the last glacial maximum implies very slow upward advective and diffusive flow of methane 1 m 1000 years in the vicinity of bsrs bsrs appears where there are no resolvable steeply dipping faults and fractures consistent with very low advective flow rates and has dispersed where vertical fractures are visible free gas released by the shift in the bsr either migrates so slowly that it remains stable beneath the ghsz or is directed upward along fractures to reform as hydrate in the ghsz there is no evidence for release of this free gas into the ocean or atmosphere

distribution of the methanotrophic bacteria in the western part of the upper silesian coal basin borynia zofiowka and budryk coal mines abstract in the past decade several research projects were undertaken to examine the relationship between qualitative and quantitative parameters of the coal bed gas and microbial inhabitants of the subsurface environment majority of the studies focused on methanogens due to their potential to improve the yields of methane extracted for industrial use but recently it was found that the coal bearing sediments are also a habitat of the methane oxidizing bacteria these microbiota comprise an important element of the carbon cycle however so far distribution and geochemical controls of their activity were poorly recognized the current study addresses this dearth of knowledge and provide data about distribution of aerobic methane oxidizers in the western part of the upper silesian coal basin one of the most important and prospective mining regions in europe the coal seams investigated nos 358 364 401 405 406 410 413 and 502 were of bashkirian age and located at depths from c a 700 to 1000 m below surface methanotrophic bacteria were ubiquitous with activity ranging from 0 191 to 2 513 m ch 4 g 1 day 1 in the laboratory conditions 30 c 100 water capacity whc and 10 v v ch 4 16s rrna sequences retrieved from the coal bed rocks revealed the presence of a variable methanotrophic community comprising of type i ii and x methanotrophs with the latter being assumed to play a dominant role in subsurface methane oxidation it was assumed that the methanotrophic bacteria present in the carboniferous coal deposits should be further investigated to assess their contribution to the safety of mining operations and due to their potential to be used as a biofilter for methane

trapping and migration of methane associated with the gas hydrate stability zone at the blake ridge diapir new insights from seismic data abstract the blake ridge diapir is the southernmost of a line of salt diapirs along the carolina trough diapirs cause faulting of the superjacent sediments creating pathways for migration of fluids and gas to the seafloor we analyzed reflection seismic data from the blake ridge diapir which is located in a region with known abundant gas hydrate occurrence a striking feature in these data is a significant shallowing of the base of gas hydrate stability bghs over the center of the diapir the seafloor is warped up by about 100 m above the diapir from about 2300 m to about 2200 m the bghs as indicated by a bottom simulating reflection bsr is about 4 5 s off the flanks of the diapir rising to about 4 15 s at the center above the diapir a fault system appears to rise vertically from the bghs to about 0 05 s below the seafloor 40 50 m it then diverges into several steeply dipping faults that breach the seafloor and cover an area 700 m in diameter other secondary faults diverge from the main fault or emerge directly from the bghs near the crest of the diapir gas and other fluids may migrate upward through the faults we performed complex trace analysis to compare the reflection strength and instantaneous frequency along individual reflections a low frequency anomaly over the center of the diapir indicates high seismic attenuation this is interpreted to be caused by migration of fluids probably methane along fault pathways the migration of gas i e probably mainly methane through the gas hydrate stability zone is not yet understood we speculate that pore fluids in the faults may be too warm and too salty to form gas hydrate even at depths where gas hydrate is stable away from the diapir alternatively gas hydrates may seal the fault walls such that water supply is too low to transform all the gas into gas hydrates the shallowing of the bsr may reflect increased heatflow above the diapir either caused by the high thermal conductivity of the underlying salt or by advective heat transport along with fluids high pore water salinity shifts the gas hydrate stability to lower temperatures and may also play a significant role in bsr shallowing we therefore investigated the possible effect of pore water salinity on shallowing of the bsr we found that bsr shallowing may theoretically be entirely caused by increased salinity over the diapir although geologically this would not be reasonable this observation demonstrates the potential importance of pore water salinity for lateral variations of bsr depths in particular above salt structures

isotopically heavy oxygen containing siderite derived from the decomposition of methane hydrate authigenic siderite from the miocene and pliocene sediments of the blake outer ridge formed in a methane fermentation zone in equilibrium with anomalously heavy oxygen water as evidenced by its heavy carbon 1 6 to 12 5 13c and heavy oxygen 0 1 to 7 9 18o values blake outer ridge sediments are impregnated with methane hydrate which is generally enriched in 18o relative to ambient water this suggests that decomposition of methane hydrate and subsequent release of large amounts of methane and heavy oxygen water affected the formation of the 18o enriched siderite gas hydrate reaction in sediments is an important process for causing a dramatic variation of oxygen isotopic composition of the interstitial water and of authigenic carbonates formed during burial diagenesis

soil formation in loess derived soils along a subhumid to humid climate gradient northeastern iran abstract in order to contribute to the understanding of carbonate enrichment and clay illuviation in loess derived soils of subhumid to humid regions the development of soils was studied along a climate gradient with xeric and udic soil moisture regimes smr and thermic and mesic soil temperature regimes str respectively in the golestan province northeastern iran six representative pedons along a climate gradient were investigated soils were classified mainly as hapludalfs and haploxeralfs stability of the geomorphic surface under forest vegetation associated with high leaching conditions has provided appropriate conditions for decalcification followed by clay migration through the profile and formation of argillic horizons in all the studied soils clay content of the bt horizons soil organic carbon concentration of the a horizons and depth of the bk horizons increased significantly with increasing precipitation and decreasing temperature there was a considerable decrease in silt content with soil development the main pedofeatures observed in the bt horizons were clay coatings and decalcified zones nodules coatings and hypocoatings were the main calcitic pedofeatures observed in the bk horizons occurrence and preservation of clay coatings were more pronounced in the udic regions with illite and vermiculite as the dominant clay minerals type of clay minerals shrink swell properties and precipitation rate are factors affecting the abundance and preservation of clay coatings in the strongly developed horizons of the udic smr the occurrence of vermiculite clay minerals could reduce the shrink swell potential and increase the amount of clay coatings the presence of crystallitic b fabrics and the high carbonate contents caco 3 in the lower horizons bk were mainly related to decalcification processes under descending water flow in the overlying horizons

numerical studies of improved methane drainage technologies by stimulating coal seams in multi seam mining layouts abstract this paper presents procedures and results of the numerical modelling of different stimulation methods as applied to the specific conditions of a multi seam mining layout at the zofiowka coal mine operated by jastrzebska spolka weglowa jsw poland studies reported in this paper include constructions of three types of numerical models 1 a geological model of the zofiowka coal mine area based on large set of available data structure maps cross sections well logs lithological profiles laboratory measurements 2 both large and small scale geomechanical models including the multi seam mining layout and details of local geomechanical conditions resulting from the application of different stimulation technologies 3 dynamic flow models including transport properties modified by the geomechanical state of the analysed seam and its surroundings resulting drainage process simulations were performed for three different technologies hydraulic fracturing high pressure jet slotting and the use of explosives detailed analyses of the technologies pointed out the hydrofracturing and jet slotting as the stimulating methods that can potentially enhance methane drainage from the analysed seam quantitative results of the simulations estimate the dependence of the drainage process characteristics upon the basic technological parameters of the stimulation methods

early and middle holocene soils at the lubbock lake archeological site texas summary two buried soils have been identified in early and middle holocene sediments at the lubbock lake site a well stratified archeological locality in yellowhouse draw lubbock county texas the firstview soil formed in organic rich lacustrine and sandy eolian sediments deposited from 11 000 to 8 500 yr b p the soil developed from 8 500 to about 6 300 yr b p and exhibits o a c and a c profiles the lacustrine facies found along the valley axis has a relatively high organic matter content contains abundant silicified root remains and commonly exhibits a gley horizon immediately below the a horizon indicating that the soil formed in a marsh with the water table at or just below the surface the soil becomes coarser grained better drained and weakly calcareous toward the valley margin reflecting the facies change in parent material the overlying yellowhouse soil formed in highly calcareous lacustrine sediments along the valley axis and sandy eolian material along the valley margin with deposition and pedogenesis occurring between 6 300 and 5 000 yr b p the soil exhibits a c and sometimes a b c profiles the relatively high organic matter content of the a horizon and minimal leaching of carbonate in the c horizon of the valley axis facies suggest that the water table was high during pedogenesis the valley margin facies of the soil exhibits some evidence of clay illuviation the contrasting field and chemical characteristics of the valley axis facies of the two soils and the sedimentological data indicate a sudden change in the water geochemistry and local environmental change soils with morphologies parent material and age similar to that of the firstview soil are not common in valley fills on the southern high plains whereas soils similar to the yellowhouse soil are widespread these data indicate a regional climatic change toward conditions of increased eolian activity reduced effective moisture and possibly warmer temperatures

eileen johnson s legacy of research the discussion begins where her career on a national and international basis began at lubbock lake that starting point lead to significant broadening of her research both intellectually and geographically and was reflected in the work of her collaborators and students in paleoindian archaeology in all other archaeological time periods and traditions on the southern plains in the method and theory of zooarchaeology and quaternary vertebrate paleontology work beyond the high plains and sustained long term research programs both on and beyond the southern plains