biaxial vitrinite reflectance in coals of the elk valley coalfield southeastern british columbia canada ninety nine grab coal samples collected from ten different diamond drill cores from the jurassic cretaceous mist mountain formation in the elk valley coalfield in southeastern british columbia were analyzed petrographically for mean maximum vitrinite reflectance rmax mean random vitrinite reflectance rm and the lengths of the maximum intermediate and minimum axes of the reflectance indicating surface or ris of vitrinite rmaxrint andrmin coal rank in the coalfield ranges from high volatile a to low volatile bituminous values of rmax in the core samples range from 0 95 to 1 50 rmax rm rmax rint and rmin are all strongly intercorrelated r 0 89 in all combinations the vitrinite in all samples is biaxial in most cases biaxial negative as a consequence rmax is always less than rmax the relationship being rmax 1 044 rmax there is no relationship between degree of vitrinite reflectance anisotropy as represented by the ris shape and rank the results indicate that a secondary stress field not perpendicular to bedding existed during coalification

paleodrainage on the chukchi shelf reveals sea level history and meltwater discharge abstract chirp subbottom data collected across the chukchi shelf offshore nw alaska imaged numerous paleochannels and valleys that appear to have been downcut and incised during sea level falls associated with glacial intervals in contrast the two most recent incisions appear to have been formed during the period of sea level rise following the last glacial maximum lgm the architecture and infill associated with these two incisions suggests that they were formed by an increase in discharge these events appear to be unrelated to sea level fluctuations but rather triggered by climatic variations during the most recent deglaciation i e meltwater discharge radiocarbon dates from sediment cores within the southern incised valley suggest that the two episodes of meltwater discharge may correlate with meltwater pulse 1 a 14 000 cal yr bp and evidence of iceberg scouring on outer chukchi shelf 12 000 to 13 000 cal yr bp respectively regional transgression across the interfluves on the middle chukchi shelf appears to postdate the second meltwater discharge and may correlate with meltwater pulse 1 b 11 500 cal yr bp this evidence suggests that in glacially dominated landscapes episodes of large discharge to the shelf might be out of phase with the sea level cycle in addition the presence of glacial meltwater drainage on the shelf implies a greater volume of continental glaciation during the lgm than previously recognized

functional groups and elemental analyses of cuticular morphotypes of cordaites principalis germar geinitz carboniferous maritimes basin canada well preserved cuticles were isolated from cordaites principalis germar geinitz leaf compressions i e foliage from extinct gymnosperm trees coniferophyta order cordaitales the specimens were collected from the sydney stellarton and bay st george subbasins of the once extensive carboniferous maritimes basin of atlantic canada fourier transformation of infrared spectra ftir and elemental analyses indicate that the ca 300 306 million year old fossil cuticles share many of the functional groups observed in modern cuticles the similarities of the functional groups in each of the three cuticular morphotypes studied support the inclusion into a single cordaite leaf taxon i e c principalis germar confirming previous morphological investigations vitrinite reflectance measurements on coal seams in close proximity to the fossil bearing sediments reveal that the bay st george sample site has the lowest thermal maturity whereas the sites in sydney and stellarton are more mature ir absorption and elemental analyses of the cordaite compressions corroborate this trend which suggests that the coalified mesophyll in the leaves follows a maturation path similar to that of vitrinite comparison of functional groups of the cordaite cuticles with those from certain pteridosperms previously studied from the y1 sydney subbasin shows that in the cordaite cuticles highly conjugated c o 1632 cm bands dominate over carbonyl stretch that characterizes the pteridosperm cuticles the differences demonstrate the potential of chemotaxonomy as a valuable tool to assist distinguishing between carboniferous plant fossil groups published by elsevier science b v

palaeontology and taphonomy of late quaternary fossil assemblages at somersham cambridgeshire england and the problem of reworking assemblages of foraminifers ostracods and molluscs from temperate ipswichian stage last temperate stage sediments and overlying cold devensian stage last cold stage sediments at somersham in the southern fenland of cambridgeshire have been analysed the ipswichian sediments contain faunas consistent with temperate brackish water conditions under tidal influence the devensian assemblages were recovered from a series of sands and gravels laterally accreting in a channel cutting into ipswichian sediments in contrast to the ipswichian faunas the faunas of particular devensian samples show a complex mixture of temperate freshwater brackish and marine taxa the molluscs are mainly freshwater with few land snails they occur together with foraminifers and ostracods freshwater brackish water and marine ostracods are present with foraminifers a sample of devensian fine laminated sediment in the channel was analysed for pollen only abundant pre quaternary spores were present with abundant foraminifers in the same sample the taphonomy of the assemblages and the difficulties of their interpretation in environmental terms are discussed the importance of taphonomy in assessing environments climate range of taxa and dating is stressed

subsidence in late paleozoic basins in the northern appalachians during the interval between continental collision in the devonian and continental breakup in the triassic the northern appalachians became the site of a wide plate boundary zone of dominantly right lateral strike slip as is typical of intracontinental transforms tectonism was both diachronous and rapidly variable along strike through regimes of pure strike slip transpressional deformation and rapid subsidence of extensional basins up to 9 km of mainly nonmarine clastic sediments accumulated in these local depocenters which subsided episodically in two stages 1 an initial phase of stretching and thinning of the lithosphere when subsidence was rapid fault controlled and often accompanied by volcanism and 2 a subsequent phase of gradual thermal subsidence during which the depositional basins expanded to bury the earlier border faults and progressively younger sedimentary units onlapped basement the largest depocenter the magdalen basin opened as a pull apart between strike slip faults in newfoundland and new brunswick from late devonian to early carboniferous subsequent thermal subsidence affected a large area during medial and late carboniferous a phenomenon that is well recorded to the north and west where no later tectonism occurred in areas to the south and east of the basin strike slip on other faults continued into the time of thermal subsidence introducing complications such as localized transpressional deformation and rapid subsidence in smaller pull aparts

synthesis and model of formation water flow alberta basin canada based on a large amount of publicly available data several studies have previously examined the flow of formation waters in different parts of the alberta basin offering various interpretations as to the causes of the observed pressure regime and flow pattern however there has been no synthesis of these diverse studies on a basin wide basis accordingly these studies are critically reviewed in this paper and synthesized in a new basin scale model of the flow of formation waters in the alberta basin the proposed regional scale model has significant implications for understanding hydrocarbon migration pathways ore genesis the geothermal regime and deep waste disposal in the alberta basin several flow systems each one driven by a different mechanism are identified together with the main processes leading to the nonhydrostatic pressures observed in the basin two megahydrostratigraphic successions and associated flow systems are recognized the first succession corresponds to the pre cretaceous passive margin stage of basin development and consists of thick carbonate dominated aquifer systems separated by shaly aquitards and evaporitic aquicludes a northeastward basin scale flow system is driven by basin topography with recharge in montana and discharge in northeastern alberta southwest to northeast regional scale flow adjacent to the fold and thrust belt is probably the result of past tectonic processes the salinity of formation water in pre cretaceous aquifers is high and generally increases both northward and with depth this variability is the result of increased water rock reactions mineral solubility with increased temperatu e and of incomplete flushing by meteoric water as a result of salinity variations flow retarding buoyancy effects can be important the second megahydrostratigraphic succession corresponds to the post jurassic foreland stage of basin evolution and consists of thick shaly aquitard systems and relatively thin sandstone aquifers in the southwestern part of the basin flow in isolated aquifers is driven southwestward by erosional rebound in the thick intervening shales downdip toward the fold and thrust belt the salinity of formation waters in the post jurassic aquifers is low mixing of waters and interference between the major flow systems takes place along the pre cretaceous unconformity where successively older pre cretaceous aquifers subcrop from west to east flow in shallow lo al systems at the top of the sedimentary succession is driven by local topography

coal rank and burial history of cretaceous tertiary strata in the grande cache and hinton areas alberta canada implications for fossil fuel exploration the present study discusses coal rank and burial histories for cretaceous tertiary coal measures and thermal maturity of associated source rocks coal rank ranges from subbituminous to semianthracite coalification maps for selected coal zones indicate a broad coalification maximum east of the deformed belt in the pocahontas brule and hinton areas rank levels appear to be elevated locally due to geothermal anomalies thermal modelling indicates that the westward decrease of coal rank in lower cretaceous strata is related to a westward decrease in the duration of burial beneath maastrichtian eocene foreland basin deposits upper cretaceous tertiary strata were subjected to relatively low geothermal gradients 20 c km whereas lower cretaceous strata were exposed to much higher gradients up to 46 c km tectonic loading in the foothills had only a minor impact on coalification at obed marsh alberta syncline thermal modelling suggests that deformation in the thrust belt continued for at least

the dynamic arctic research campaigns over the last decade have yielded a growing stream of data that highlight the dynamic nature of arctic cryosphere and climate change over a range of time scales as a consequence rather than seeing the arctic as a near static environment in which large scale changes occur slowly we now view the arctic as a system that is typified by frequent large and abrupt changes the traditional focus on end members in the system glacial versus interglacial periods has been replaced by a new interest in understanding the patterns and causes of such dynamic change instead of interpreting changes almost exclusively as near linear responses to external forcing e g orbitally forced climate change research is now concentrated on the importance of strong feedback mechanisms that in our palaeo archives often border on chaotic behaviour the last decade of research has revealed the importance of on off switching of ice streams strong feedbacks between sea level and ice sheets spatial and temporal changes in ice shelves and perennial sea ice as well as alterations in ice sheet dynamics caused by shifting centres of mass in multi dome ice sheets recent advances in dating techniques and modelling have improved our understanding of leads and lags that exist in different arctic systems on their interactions and the driving mechanisms of change future arctic research challenges include further emphases on rapid transitions and untangling the feedback mechanisms as well as the time scales they operate on

mid to late pleistocene ice drift in the western arctic ocean evidence for a different circulation in the past the provenance of ice rafted debris ird in four arctic sediment cores implies that icebergs from the northwestern laurentide ice sheets drifted across the western arctic ocean along the 180 0 meridian toward fram strait during mid to late pleistocene deglaciations within the last 700 000 years this iceberg drift was different from the present day beaufort gyre circulation and resembled a dislocated transpolar drift tpd sea ice mainly followed the iceberg trajectories but also frequently drifted from the russian shelves eastward into the amerasian basin

paragenetic relationship of thermal maturation coalification and tectonic framework of some canadian rocky mountain coals abstract use of the attitude of the optical axis of vitrinite as an indicator of paragenetic relationship of thermal maturation coalification and tectonics is discussed a constant angular relationship between the optical axis and bedding plane of coals is observed in seven coal mines in the canadian rocky mountain coal fields this constant relationship suggests that thermal maturation predated tectonic structures

coals of canada distribution and compositional characteristics abstract canada s coal resources occur in 16 sedimentary basins or groups of basins and range in age from devonian to tertiary the western canada sedimentary basin wcsb which contains the vast majority about 90 of the nation s coal resources of immediate interest underlies a large area in the provinces of british columbia alberta saskatchewan and manitoba extending northward to about the 62nd parallel in yukon and northwest territories coal deposits in the wcsb range in age from early carboniferous mississippian to paleocene rank ranges from lignite to semianthracite about 36 of the total estimated 71 000 megatonnes of resources of immediate interest in the wcsb is bituminous coal including a high proportion in the medium to low volatile range their low sulphur contents and acceptable ash levels make these medium and low volatile bituminous coals attractive 3s coking feedstocks and large quantities are mined for that purpose the lower rank western canadian coals are used mainly for electricity generation significant resources of bituminous coal occur in the coalfields of atlantic canada where they have been mined since 1720 most of these coals are classed as high volatile a bituminous and most are used for power generation large resources of coal lignite to anthracite also occur in more remote regions of canada such as the bowser basin in northwestern british columbia and sverdrup basin franklinian geosyncline in the arctic islands information on distribution and compositional attributes of these frontier region coals is commonly scarce

the cretaceous tertiary boundary in the central alberta foothills i stratigraphy the cretaceous tertiary boundary in the rocky mountain foothills occurs within a continental sequence carrying economic coal deposits and known as the coalspur formation this formation occurs between the fluvial brazeau below and paskapoo formations the exact position of the boundary is located at the base of the lowest coal mynheer within the coalspur formation the initiation of coal deposition in the coalspur formation is not a unique event as it is consistent with the cyclic pattern established within the underlying brazeau formation however the magnitude and lateral continuity of coal zone development far exceed those found in the underlying formation the classic shift from a diverse late maastrichtian flora within which angiosperm and especially aquiloid pollen are prominent to a low diversity early paleocene flora dominated by gymnosperm pollen and miospores is documented deviations from most previously recognized floral events at the cretaceous tertiary boundary include 1 san angio

the timing of coalification in relation to structural events in the grande cache area alberta canada lower cretaceous coals from the inner foothills of the rocky mountains were sampled for a study of the relationships between coal rank and folding and faulting the coals were collected from laterally continuous seams in a highly folded and faulted area near grande cache alberta rank of the coals as determined by measuring mean maximum vitrinite reflectances ranges from medium to low volatile bituminous the results indicate that the degree of coalification was established during burial from albian to late paleocene times before folding and faulting started isoreflectance lines run parallel to the bedding of the folded strata and there are no significant changes in reflectances in the same seam from one thrust sheet to the other however in the footwall of the mason thrust the mean maximum reflectances and bireflectances are locally increased above regional values regionally there appears to be a trend to slightly lower reflectances in the southeast of the study area it is suggested that the low

organic petrography and geochemical characterization of the upper cretaceous second white specks and upper belle fourche alloformations west central alberta analysis of local maturity anomalies abstract the second white specks is an enigmatic unconventional shale play in the western canada foreland basin wcfb this play has an inconsistent production performance that has impacted exploration and production risk preventing extensive development in this contribution geochemical properties are studied with the purpose to identify possible geochemical factors that could contribute to the production variability of this unconventional petroleum system the studied succession consists of the second white specks sws and upper belle fourche ubf alloformations which are part of the sws shale play organic petrology and rock eval pyrolysis were combined to characterize the organic matter om and assess om richness thermal maturity and hydrocarbon generation potential in the foredeep section of the basin the results show that the om richness and hydrocarbon generation potential in this area is good and comparison with other studies show that they do not exhibit major lateral variations the kerogen is marine type ii and is dominated by liptinite vitrinite inertinite macerals and solid bitumen alginite and bituminite are the most abundant macerals altered bituminite provides evidence of anaerobic bacteria degradation there is a modest contribution of inertinite that may be responsible for a dilution effect of the pyrolyzable carbon the thermal maturity indicators in this study such as vitrinite reflectance tmax and alginite uv fluorescence color indicate that the controls on thermal maturity and hydrocarbon generation are not well understood there are lateral short scale variations or maturity anomalies that require further investigation to reduce the exploration risk

late glacial drainage systems along the northwestern margin of the laurentide ice sheet abstract the evolution of drainage systems along the retreating northwestern laurentide ice sheet was complex the interaction of ice margin configuration topography and glacioisostasy resulted in a network of meltwater rivers that variably overflowed to the arctic and pacific oceans and to the gulf of mexico glacial lakes also changed dramatically in size and location during the period of deglaciation at the last and all time glacial maximum the ice sheet extended into the eastern cordillera blocking northward and eastward drainage to the arctic ocean some meltwater and most non glacial runoff were diverted through the mountains to the yukon river basin into alaska and the pacific ocean retreat from the glacial maximum prior to 21 ka bp allowed proglacial drainage from the western margin of the ice sheet to flow into the beaufort sea arctic ocean deglaciation was rapid after about 13 ka bp with the present route of the lower mackenzie river established between 13 and 11 5 ka bp continued ice retreat led to significant southward expansion of the mackenzie beaufort drainage basin at about 11 5 ka bp through drainage capture of glacial lake peace which previously had drained southeastward into the missouri river and to the gulf of mexico very rapid ice retreat between 10 5 and 10 ka bp allowed glacial lake mcconnell to expand down slope in contact with the ice margin numerous glacial lakes occurred along the northwestern margin of the ice sheet during the maximum and retreat phases these include ice dammed glacial lake old crow which occupied unglaciated terrain of the northern yukon and glacial lake peace which utilized a number of outlets as it migrated eastward with the ice front along the peace valley the largest glacial lakes in the region were the result of glacioisostatic depression reversing the regional drainage the mackenzie phase of glacial lake mcconnell was the second largest pleistocene lake in north america 215 000 km 2 late glacial and post glacial changes in drainage systems were largely in response to isostatic rebound

organic petrology and rockeval analysis of the lower carboniferous emma fiord formation in sverdrup basin canadian arctic archipelago abstract samples of the lower carboniferous emma fiord formation from two localities in the sverdrup basin of arctic canada were examined using reflected white and fluorescent light the samples from kleybolte peninsula on ellesmere island show a relatively high level of thermal maturity in contrast those from grinnell peninsula on devon island are immature to marginally mature and include subbituminous coals and oil shales two types of oil shales are distinguished on the basis of liptinite content mineral matrix rockeval pyrolysis analysis and concentration of boron one is characterized by a liptinite rich clay carbonate matrix with a relatively high hydrogen index and boron content and the other by a liptinite poor carbonate matrix with a relatively low hydrogen index and boron content hydrogen rich components of these shales consist of alginite matrix bituminite and minor amounts of exsudatinite and sporinite kerogen types iii and iv comprise only minor components of the organic matter thermal maturity of the grinnell peninsula oil shales increases with depth matrix bituminite in these oil shales has seeped into cavities and microfractures in the kerogen types iii and iv forming exsudatinite the distribution and character of the organic constituents and also the concentration of boron in these samples indicate a fresh to brackish water environment

the sporormiella proxy and end pleistocene megafaunal extinction a perspective counts of dispersed spores of the pyrenomycete dung fungus sporormiella have recently gained prominence as a technique to examine the end pleistocene mass extinction early investigations were able to identify sporormiella occurrence on the dung of extinct species including squirrel and mammoth these early studies also noted an important trend in sporormiella abundance over time in north america such that spore abundances were high during the late pleistocene low for most of the holocene and again prominent with the introduction of large grazing animals by early explorers in more recent studies changes in the abundance of spores of this fungus in sediments have been used as a proxy to define megafaunal population presence decline and extinction during the late pleistocene and a number of sites in the northeastern usa show a similar pattern of sporormiella abundance over time it is our opinion that some critical taxonomic and taphonomic investigations have not been completed for sporormiella and because of this there are complications in interpreting the sporormiella spore abundance data we constructively evaluate this analytical technique and propose supporting studies that could enhance its potential as an indicator of megaherbivore extinction and its use as a proxy for the end pleistocene extinction

organic maturity in the western canada sedimentary basin abstract organic maturity of strata in the western canada sedimentary basin has been investigated in numerous studies using petrological chemical and physical methods compilation of these data has facilitated a regional analysis of the maturity patterns and maturation history variation in maturity patterns can be divided into three levels basin wide 1st order regional 2nd order and local 3rd order first order variations are manifested by an overall increase in maturity of strata of the same age from east to west from the plains to the rocky mountain foothills and front ranges in response to progressively deeper burial and higher paleo geothermal gradients superimposed on this first order basinal scale variation in maturity are second and third order variations which reflect local differences in depth of burial conductive and advective heat transport or effects of thrust faulting maturity gradients in the axis of the basin are low averaging 0 10 log r omax km whereas in the front ranges and foothills the gradients are substantially greater average 0 25 log r omax km variations in maturity gradients reflect lower paleo geothermal gradients resulting from rapid sediment loading and subsequent unloading in the plains and higher conductive heat transport in the deformed belt the main component of maturity of most phanerozoic strata occurred during deep burial under upper cretaceous and or paleogene molasse in foredeeps developed in response to crustal loading during the easterly migration of the foreland fold and thrust belt as a result of the west to east propagation of deformation during the laramide orogeny deep burial maturation hydrocarbon generation and uplift occurred earlier in the foreland belt late cretaceous than in the plains to the east where the main component of maturity and hydrocarbon generation occurred as late as eocene in the plains because of the low maturity gradients a thick succession of strata currently is within the oil window in the deformed belt however higher maturity gradients have resulted in a thinner succession of strata within the oil window in response to higher paleo geothermal gradients strata in the deformed belt matured more quickly leading to more rapid hydrocarbon generation and migration than areas to the east in the southern part of the cordillera a significant component of maturation post dates structural deformation of the strata whereas in northeastern british columbia and adjacent parts of alberta maturity primarily pre dates structural deformation data from some deep bore holes and surface samples in the southern part of the cordillera provide evidence for maturity post dating or accompanying emplacement of major overthrust sheets tectonic burial in most areas however there is no clear evidence for the timing of maturity relative to faulting or evidence of frictional heating the maturity gradients and levels of maturity of surface and near surface strata in the western plains and rocky mountain foothills indicate that a succession several kilometres of paleogene strata were deposited in these regions foredeep and subsequently eroded in response to post laramide uplift

raman spectroscopy an effective thermal marker in low temperature carbonaceous fold thrust belts special publication title fold and thrust belts structural style evolution and exploration acknowledgments z crawford and a marpino were funded through the university of aberdeen school of geosciences for mgeol and msc project work bond butler and watkins were supported through the fold thrust research group sponsored by oil search santos and interoil

a new technique for obtaining high resolution pore pressure records in thick claystone aquitards and its use to determine in situ compressibility 1 laboratory tests are commonly used to determine properties vertical compressibility specific storage ss and vertical hydraulic conductivity kv of claystone aquitards however whether data representative of in situ conditions can be obtained from disturbed samples is questionable here we present a method to determine the in situ and ss of a thick sequence of cretaceous aged claystone by estimating the loading efficiency of a formation from pore pressure responses to barometric pressure fluctuations we installed 10 vibrating wire pressure transducers at different depths 25 325 m below ground in a thick claystone aquitard by placing them directly within the cement bentonite grout two years of continuous transducer records using this method appeared to provide pore pressure data with a resolution of better than one part in 105 equivalent to millimeter of hydraulic head change pore pressure responses to barometric pressure changes earth tides and precipitation events can be clearly identified and the barometric responses can be easily analyzed the resulting values of 0 6 0 93 2 5 10 7 to 2 2 10 6 kpa 1 and ss 2 6 10 5 to 4 5 10 6 m 1 all decrease with depth the results are comparable with the limited existing data for in situ estimates of ss and are as much as an order of magnitude smaller than laboratory estimates of ss for similar aquitard deposits our findings suggest that the fully grouted transducer method can provide an accurate and reliable means to monitor pore pressure changes and to determine in situ parameters for bedrock aquitard systems

pore water evolution in sandstones of the groundhog coalfield northern bowser basin british columbia abstract the succession of sandstone cements in chert and volcanic lithic arenites and wackes from the northern bowser basin of british columbia comprises a record of diagenesis in shallow marine deltaic and coastal plain siliciclastic sediments that pass through the oil window and reach temperatures near the onset of metamorphism the succession of cements is consistent with seawater in the sandstones mixing with acid waters derived from dewatering of interbedded organic rich muds sandstone cement paragenesis includes seven discrete cement stages from earliest to latest the cement stages are 1 pore lining chlorite 2 pore lining to pore filling illite 3 pore filling kaolinite 4 oil migration through some of the remaining connected pores 5 chlorite dissolution 6 quartz cement and 7 calcite cement these seven cement stages are interpreted as a record of the evolution of pore waters circulating through the sandstones after burial the earliest cement stages as well as the depositional environments are compatible with seawater as the initial pore fluid seawater composition changed during transport through the sandstones first by loss of mg2 and fe2 during chlorite precipitation stage 1 dewatering of interbedded organic rich mudstones probably added mg2 and fe2 to partially buffer the loss of these cations to chlorite acids produced during breakdown of organic matter are presumed to have mixed into sandstone pore fluids due to further compaction of the muds leading to reduction of initial alkalinity reduction in alkalinity in turn favours change from chlorite to illite precipitation stage 2 and finally to kaolinite stage 3 pore waters likely reached their peak acidity at the time of oil migration stage 4 chlorite dissolution stage 5 and quartz precipitation stage 6 occurred when pores were filled by these hydrocarbon bearing and presumably acidic fluids fluid inclusions in fracture filling quartz cements contain petroleum high pressure methane and methane rich aqueous solutions homogenization temperatures from primary two phase inclusions are consistent with quartz cementation during progressive heating between approximately 100 and 200 c following quartz precipitation alkaline pore waters were re established as evidenced by late stage calcite cement stage 7

fluid flow mixing and the origin of co2 and h2s by bacterial sulphate reduction in the mannville group southern alberta canada abstract sandstone reservoirs of the mannville group in southern alberta host petroleum and natural gas deposits with abnormally high amounts of co2 and h2s produced water and gas chemistry and isotopic composition suggests that bacterial sulphate reduction has taken place limited isotopic data for gas samples indicate that co2 is organic with calcite dissolution accounting for intermediate 13c values for bicarbonate co2 and h2s are thought to be formed by bacterial sulphate reduction bsr the rate of which is dependent on the rate of supply of sulphate h2s has been precipitated as pyrite and removed from the system co2 from both bacterial sulphate reduction and resulting water rock reactions has accumulated in quartz rich sandstone reservoir rocks causing the amount of co2 in the gas to be much higher than h2s anomalously high co2 and h2s concentrations are coincident with the jurassic subcrop edge and are related to cross formational fluid flow sulphate rich waters from mississippian aquifer units that underlie the jurassic aquitard mix with waters in mannville sandstone at the subcrop edge organic acids ratios in mannville waters suggest that coaly material not petroleum hydrocarbons may provide the organic food source required for sulphate reducing bacteria

isomerization and aromatization of hydrocarbons and the paleothermometry and burial history of alberta foreland basin the hydrocarbon fractions extracted from 34 cretaceous shales from a cross section of the alberta basin have been analyzed using gas chromatography mass spectrometry particular attention has been paid to the extents to which three temperature dependent geochemical reactions have occurred isomerization of steranes at c 20 isomerization of hopanes at c 22 and aromatization of c ring monoaromatic steroid hydrocarbons estimates of the kinetic constants of these reactions have been published previously therefore constraints may be put on the maximum temperature experienced by the sediments and the time for which this temperature existed the subsidence history of the alberta basin is simulated using a lithospheric flexural model in which the lithosphere is downwarped by the loading of overthrusts in the adjacent cordilleran orogene when overthrusting ceases erosion of the overthrusted region lightens the load and the lithosphere rebounds causing uplift and erosion of the foreland basin major overthrusting and therefore deep burial occurred during the laramide orogeny of late cretaceous to mid tertiary time the extent of chemical reactions suggests that the present maturity of the cretaceous shales is almost entirely a reflection of burial and heating during the laramide orogeny in a manner that is consistent with the lithospheric flexural model for the basin the chemical reactions suggest that the paleogeothermal gradient increased systematically away from the foothills of the rocky mountains along the profile studied that a similar trend exists today suggests this situation has persisted at least since the early stages of the laramide orogeny this variation is best explained by advective heat transfer water entering the basin in the faulted and topographically higher foothills is heated at depth thereby depressing the geothermal gradient this hot water then migrates updip and away from the foothills to enhance the geothermal gradients in the edmonton area and beyond the route of the migrating hot water is similar to that taken by hydrocarbons from devonian and cretaceous source rocks in the deep basin updip to the oil and tar sand accumulations of alberta

freshwater outbursts to the oceans from glacial lake agassiz and their role in climate change during the last deglaciation abstract lake agassiz was the largest lake in north america during the last deglaciation as the laurentide ice sheet lis retreated large volumes of water stored in this proglacial lake were episodically released into the oceans these waters were variably routed to the gulf of mexico arctic ocean north atlantic ocean and hudson bay during this period the three largest cooling events in the northern hemisphere closely followed 4 of the 5 largest outbursts from lake agassiz 1 the younger dryas which was preceded by a release of 9500 km 3 2 the preboreal oscillation preceded by releases of 9300 km 3 and 5900 km 3 and 3 the 8 2 ka cold event preceded by a 163 000 km 3 outburst these are respectively fluxes of 0 30 sv 0 29 sv 0 19 sv and 5 2 sv if released in 1 year because the influx of freshwater reaching the north atlantic ocean can inhibit thermohaline circulation partly depending on whether the ocean was in a glacial interglacial or transitional mode of circulation we believe that at least these large outbursts from lake agassiz may have provided the triggers for changes in ocean circulation and in turn for widespread climate change

coal quality coal rank variation and its relation to reconstructed overburden upper cretaceous and tertiary plains coals alberta canada near surface coals in the alberta plains occur in upper cretaceous and tertiary sediments the former represented by the belly river group horseshoe canyon formation and wapiti formation and the latter by the scollard member of the paskapoo formation statistical techniques were used to document both the distribution of and the interrelationships among the components of proximate and ultimate analysis and calorific value determinations the coals discussed range in rank from subbituminous c to high volatile bituminous c these coals are variable in ash content and low in sulfur content the relationships among calorific value dry basis in kj kg and ash dry basis in and calorific value moist mineral matter free basis in kj kg and equilibrium moisture meq in were determined to be cvd 29 677 315 17 ashd and cvmmmf 31 816 442 05 meq respectively the maximum depth of coal seam burial dob in m was reconstructed on the basis of previously published graphs relating the equilibrium moisture loss to depth of coal seam burial using the relationship log10meq 1 865 0 000416 dob a least squares regression analysis of calorific value mmmf basis in k kg on the calculated depth of burial dob in m yielded the equation cvmmmf 14 748 6 25 dob indicating a coalification gradient determined on the reconstructed overburden of 6 25 kj kg m 0 82 btu lb ft of depth or overburden near surface coals in the alberta plains increase in rank toward the west southwest toward the foothills and mountains region because of progressively greater amounts of overburden that existed in that direction during the tertiary erosion has since removed between 900 and 1 900 m 3 000 and 6 200 ft of sediment with the greatest amount of removal occurring in a west southwest direction

total gas in place gas composition and reservoir properties of coal of the mannville coal measures central alberta abstract the lower cretaceous mannville coal measures in south central alberta host one of the most successful horizontal coal methane developments yet the contribution of thin coal seams and other organic rich strata to total gas in place and producible gas remains unaccounted in this study well log core fluid and gas analyses in the mannville coal measures are evaluated in order to quantify and characterise the total gas in place resource that may be accessed by a horizontal well completed in the main coal seam which is the usual practise regionally the estimated gas capacity and content of the coals increases from northeast to southwest in parallel with the depth of burial and the level of organic maturation rank although local variations exist the isotopic composition of the methane of coals currently at depths greater than 1500 m have a strong thermogenic signature shallower coals have a mixed biogenic thermogenic signature and the shallowest coals have a strong biogenic signature the trend in gas composition is less well defined with the highest carbon dioxide contents occurring in the area of the lowest and highest ranks generally the percentage of heavier gases c 2 c 5 increases with maturity depth of burial but some low rank coals ro 0 30 in eastern alberta and saskatchewan contain significant c 2 c 5 hydrocarbons the origin of the heavier gases in the low rank coals is unclear migration from a deeper source is the most likely explanation the gas adsorption capacity of the coals varies regionally with depth of burial pressure coal rank and ash content the highest adsorption capacity at reservoir pressure and temperature approaches 400 1 scf t but most coals have values between 260 and 320 scf t the gas content of the coals as measured by desorption ranges from 230 to 350 scf t and averages 310 scf t most of the coals are saturated with gas within the accuracy of the analyses notable exceptions occur adjacent to the saskatchewan border where the lower rank coals may be markedly under saturated the amount of methane in solution calculated at a reservoir pressure of 1000 psig 6 9 mpa is calculated to be between 7 and 10 scf t 3 of total gas currently mannville coal gas production is limited to an area in central alberta of about 2200 km 2 850 miles 2 outside the producing fairway sustained commercial production has not been achieved due to low permeability in the producing and prospective fairway the net thickness of the coal within 20 m of the main coal seam varies from 0 to 10 8 m and averages 5 1 m here the thickest coal seam ranges up to 4 7 m thick and averages 1 9 m due to limited gas content data from core for all seams and wells a protocol was developed to extrapolate existing core data to non cored seams and wells through petrophysical logs the protocol takes into consideration the correlation between gas and ash content and the maturity of the coals the total coal gas resource density in the current area of production and prospective areas determined by applying this protocol for the average well has a low estimate of 5 4 bcf mi 2 2 m 3 km 2 a median estimate of 5 9 bcf mi 2 and a high estimate of 6 1 bcf mi 2

heating during thrust faulting in the rocky mountains friction or fiction abstract measurement of the levels of organic maturation below and within shear zones of thrust faults in the rocky mountains has revealed no general thermal metamorphism that can be attributed to faulting with the exception of very localized areas with few exceptions the vitrinite reflectance values obtained are in the range expected if the maximum level of organic maturation was produced as a result of increasing temperature during progressive burial accompanying sedimentation only at marias pass evidence has been found to suggest additional maturation as a result of post orogenic burial below the thrust sheets anomalously high vitrinite reflectances obtained from the lewis thrust mcconnell thrust coleman thrust and two unnamed thrusts are restricted to very narrow films immediatly adjacent to or within the shear zone which considering any reasonable thermal conductivity indicates elevated temperatures were very short lived the anomalously high vitrinite reflectances within these films when compared to laboratory heated coals suggest temperatures in the order of 350 650 c were locally generated during faulting such high temperatures are considered to have been generated during stick slip faulting at macro asperities or at ramps on the fault plane where local and possibly transient high frictional stresses existed the absence of evidence for extensive frictional heating supports previous arguments that stable sliding and or low frictional stress must exist during thrusting

thermal history of alberta deep basin comparative study of fluid inclusion and vitrinite reflectance data the thermal history of the alberta deep basin the gas saturated westernmost part of the western canadian sedimentary basin has been studied by analyzing aqueous and hydrocarbon fluid inclusions in diagenetic cements and comparing the results with coal maturity data results indicate that most of the diagenetic quartz druse precipitated from low salinity fluids 2 3 wt at a temperature of 170 195 c calcite cement precipitated after quartz druse during uplift and cooling at temperatures of 108 169 c inclusions rich in larger hydrocarbon molecules occur in cements that precipitated at 150 c whereas methane rich inclusions occur in cements that precipitated at 165 c or at lower temperatures after significant uplift and cooling of the b sin maximum burial temperatures tmb calculated from vitrinite reflectance data using the lopatin waples tti ro calibration are significantly lower 150 c than the temperature at which quartz druse precipitated in the same area 190 c an equation directly relating tmb and ro proposed by barker and pawlewicz in 1986 yields maximum burial temperatures 200 210 c only slightly higher than the fluid temperatures the results from this study suggest that hot fluids migrated updip along permeable conglomerates and bedding plane fractures to produce unexpectedly high geothermal gradients 38 c km in the western part of the study area the apparent restriction of hot fluids to the western part of the study area sugge ts that convective heat transfer by fluids may have operated on a scale of only tens of kilometers in lower cretaceous rocks of the alberta deep basin

recognition of vitrinite with non uniaxial negative reflectance characteristics non uniaxial negative reflectance characteristics are being reported for coals from around the world with increasing frequency these data have traditionally been collected from oriented sections cut from a block of coal to determine the magnitudes of the principal reflectance axes to make data collection less time consuming a method of determining the principal reflectance axes from a standard crushed coal sample has been developed the method requires measurement of the maximum and minimum apparent reflectances from a series of randomly oriented vitrinite particles the reflectance crossplot displays these two reflectance values against their difference or bireflectance the paper describes the method of interpreting the resultant pattern to determine the values of the three principal reflectance axes analysis of coals from the british columbia rocky mountains and foothills revealed biaxial and uniaxial positive as well as uniaxial negative reflectance characteristics a new measure of maturation rev is proposed which is based purely on the lengths of the three principal reflectance axes rm approximates this value but is influence by any eccentricity of the reflectance indicating surface ris vitrinite with a non uniaxial reflectance characteristics cannot be adequately described by a single measure such as rmaxorrm but requires reference to both the size and shape of the ris a reflectance determination such as rev or rm provides rank astm information whereas the new measures rst and ram describe a reflectance indicating surface shape which is the result of maturation and tectonic histories vitrinites with non uniaxial negative reflectance characteristics are abundant in the coalfields of the rocky mountains and foothills of british columbia rmax does not fully describe the reflectance character of these coals and does not describe the potentially useful ris shape

regional coalification pattern of lower cretaceous coal bearing strata rocky mountain foothills and foreland canada implications for future exploration abstract the regional coalification pattern of lower cretaceous strata in parts of the canadian foothills belt and adjacent foreland has been determined by vitrinite reflectance measurements the present study focusses on two coal bearing sequences bluesky gething and gates formation both of which contain coal resources of economic interest the vitrinite reflectances r max in the bluesky gething formation range from 0 76 high volatile a bituminous to 2 55 semianthracite rank changes from top to the base of bluesky gething formation follow 1st order regression lines factors influencing the rate of increase of r max per depth interval coalification gradient include paleogeothermal gradients the rank level under investigation conductivities of host rocks and thicknesses of coal seams time depth burial curves for the lower cretaceous bluesky gething formation suggest that the regional coalification pattern for the top of the formation results largerly from variations in the depth and or duration of burial beneath maastrichtian tertiary foredeep deposits coalification largerly predates deformation the coalification pattern is more complicated for the base of the bluesky gething formation because thickness changes in the lower cretaceous bluesky gething interval locally have a greater effect on the rank than does the regional change in the thickness of maastrichtian tertiary sedimentary wedge detailed rank studies on laterally continuous coal seams of the gates formation showed that coalification levels were largerly established before folding and thrusting started isoreflectance lines of the beds run parallel to the bedding of the folded strata seams collected from various thrust sheets exposed at surface do not in general show significant changes in vitrinite reflectances from one thrust sheet to another many of the coals of the gates formation were found to have biaxial negative reflectance in dicatrices orientation of r max is in all cases parallel of subparallel to the mactroscopic fold axes indicating preferential orientation of the aromatic lamellae in the coals in the direction of minimum compressive stress it is suggested that the occurrence of biaxial negative coals is related to a tectonic stress field that existed during the later stages of burial and subsequent deformation

deformation of upper carboniferous coal measures in the sydney basin evidence for late alleghanian tectonism in atlantic canada upper carboniferous stephanian coal measures of the sydney basin are deformed by reverse faults and folds with dips of up to 50 on the limbs these structures represent compressional or transpressional events donkin episode of unknown sequence and timing offshore swath bathymetry data indicate that northwest striking reverse faults are folded by prominent northeast trending folds vitrinite reflectance patterns of oriented coal samples from the fold limbs are uniaxial negative with minimum reflectance axes rmin near normal to bedding and fanning across fold axes this pattern implies that the bulk of coalification took place through burial compaction without directed horizontal stress prior to the deformation that produced the folds slight divergence between rmin axes and poles to bedding may reflect slight tilting associated with differential subsidence or early reverse faulting before or during coalification or may lie within analytical error one moderately biaxial sample suggests that some deformation accompanied coalification locally available apatite fission track data for the sydney basin indicate that cooling of the coal measures to below 100 20 c was underway by the middle to late triassic or earlier because cooling implies that coalification was largely complete the fission track results are compatible with latest paleozoic or early mesozoic deformation we infer that the donkin episode represents late alleghanian permian compression within the appalachian orogen if so the sydney structures are manifestations of a little known tectonic episode in atlantic canada however mesozoic cenozoic deformation cannot be ruled out resume les series houilleres du bassin de sydney carbonifere superieur stephanien sont deformees par des failles inverses et des plis deverses dont les flancs atteignent des pendages de 50o ces structures representent des evenements de compression ou de transpression episode donkin dont la sequence et la synchronisation sont inconnues les donnees de bathymetrie par secteurs au large indiquent que les failles inverses a direction nord ouest sont pliees par des plis proeminents a tendance nord est les patrons du facteur de reflexion de la vitrinite provenant d echantillons de charbon orientes preleves sur les flancs des plis sont uniaxes negatifs avec des axes de reflectance minimum rmin presque perpendiculaires au litage et se dispersant en travers des axes de plis ce patron implique que la plus grande part de la carbonisation a eu lieu par compaction d enfouissement sans contrainte horizontale directe avant la deformation qui a produit les plis la legere divergence entre les axes rmin et les poles du litage pourrait refleter un leger basculement associe a une subsidence differentielle ou a des failles inverses precoces avant ou durant la carbonisation ou encore cette divergence pourrait etre a l interieur de la fourchette de l erreur analytique notre echantillon moderement biaxe suggere qu une certaine deformation ait localement accompagne la carbonisation pour le bassin de sydney les donnees disponibles de datation par traces de fission sur l apatite indiquent que le refroidissement des series houilleres a des temperatures inferieures a 100 20 oc etait deja en cours au trias moyen a tardif ou plus tot puisque le refroidissement implique que la carbonisation etait presque terminee les resultats de datation par traces de fission concordent avec la deformation au paleozoique terminal ou au mesozoique precoce nous concluons que l episode donkin represente une compression a l alleghanien tardif permien a l interieur de l orogene des appalaches si tel est le cas les structures de sydney sont des evidences d un episode tectonique peu connu au canada atlantique cependant une deformation au mesozoique cenozoique ne peut etre rejetee d emblee

nonassociation of paleoindians with ams dated late pleistocene mammals from the dutchess quarry caves new york abstract ams 14 c ages of 10 bones of the caribou rangifer tarandus flat headed peccary platygonus compressus and giant beaver castoroides ohioensis from the dutchess quarry caves new york range from 13 840 80 to 11 670 70 yr b p no bones from any of these species are demonstrably associated with paleoindian artifacts fluted points or other cultural materials from the sites because the bones lack unequivocal stratigraphic association with artifacts as well as physical taphonomic evidence for human association e g burning cut marks distinctive breakage together with the holocene conventional 14 c dates of charcoal and the varied stratigraphic proveniences of the fluted points and the dated bones the new ams 14 c dates argue that most strata at the dutchess quarry caves contain a mixture of late pleistocene and holocene materials this mixing probably resulted from post depositional bioturbation by humans rodents carnivores and scavengers and cryoturbation annual freeze thaw cycles rather than being of cultural origin the bones of caribou flat headed peccary and giant beaver likely were deposited in the dutchess quarry caves by nonhuman predators or scavengers such as ursids canids felids condors or eagles

burial history and thermal maturity rocky mountain front ranges foothills and foreland east central british columbia and adjacent alberta canada the regional pattern of maturation of cretaceous strata in the study area was determined from vitrinite reflectance measurements maturation increases from west to east across the foothills to a maximum near the eastern limit of foothills deformation and decreases farther east maturation along the eastern limit of deformation also decreases northward significantly reflectance measurements from carboniferous strata exposed in the front ranges are much lower than values from the lower cretaceous near the eastern limit of deformation modeling using burial history curves indicates the regional maturation pattern largely reflects variations in the depth and or duration of burial beneath maastrichtian eocene foredeep deposits however differential vertical movements associa ed with the peace river arch embayment in the carboniferous triassic early cretaceous and maastrichtian eocene had an important effect on the maturation pattern determined and estimated maturation levels for reservoir strata are consistent with the known occurrences of gas fields and oil pools except along the relatively unexplored western margin of the study area there moderate maturation levels indicate a potential for wet gas or oil preservation in shallow structures containing triassic and lower carboniferous carbonates in the south in the north structures in the western foothills deforming triassic strata with lower levels of maturation are breached

gas maturity and alteration systematics across the western canada sedimentary basin from four mud gas isotope depth profiles abstract carbon isotope and molecular compositions of mississippian to upper cretaceous mud gases have been examined from four depth profiles across the western canada sedimentary basin wcsb the profiles range from the shallow oil sands in the east r 0 0 25 to the very mature sediments in the overthrust zone to the west r 0 2 5 in the undisturbed wcsb 13 c 1 13 c 2 and 13 c 2 13 c 3 cross plots show three maturity and alteration trends 1 pre cretaceous gas sourced from type ii kerogen 2 cretaceous colorado group gas and 3 lower cretaceous mannville group biodegraded gas a fourth set of distinctly different maturity trends is recognized for lower cretaceous gas sourced from type iii kerogen in the disturbed belt of the wcsb displacement of these latter maturity trends to high 13 c 2 values suggests that the sampled gas was trapped after earlier formed gas escaped probably as a result of overthrusting unusually 13 c enriched gas 13 c 1 34 13 c 2 13 and 13 c 3 0 from the gething formation in the disturbed belt is the result of late stage gas cracking in a closed system in general gas maturity is consistent with the maturity of the host sediments in the wcsb suggesting that migration and mixing of gases was not pervasive on a broad regional and stratigraphic scale the deep basin portion of the wcsb is an exception here extensive cross formational homogenization of gases has occurred in addition to updip migration along the most permeable stratigraphic units

continental scale landscape evolution a history of north american topography the generation and evolution of continental topography are fundamental geologic and geomorphic concerns in particular the history of landscape development might contain useful information about the spatiotemporal evolution of deep earth processes such as mantle convection a significant challenge is to generate observations and theoretical predictions of sufficient fidelity to enable landscape evolution to be constrained at scales of interest here we combine substantial inventories of stratigraphic and geomorphic observations with inverse and forward modeling approaches to determine how the north american landscape evolved first stratigraphic markers are used to estimate postdepositional regional uplift present day elevations of these deposits demonstrate that 2 km of long wavelength surface uplift centered on the colorado rocky mountain plateaus occurred in cenozoic times second to bridge the gaps between these measurements an inverse modeling scheme is used to calculate the smoothest spatiotemporal pattern of rock uplift rate that yields the smallest misfit between 4 161 observed and calculated longitudinal river profiles our results suggest that cenozoic regional uplift occurred in a series of stages in agreement with independent stratigraphic observations finally a landscape evolution model driven by this calculated rock uplift history is used to determine drainage patterns denudation and sedimentary flux from late cretaceous times until the present day these patterns are broadly consistent with stratigraphic and thermochronologic observations we conclude that a calibrated inverse modeling strategy can be used to reliably extract the temporal and spatial evolution of the north american landscape at geodynamically useful scales

early to mid holocene atlantic water influx and deglacial meltwater events beaufort sea slope arctic ocean abstract holocene high resolution cores from the margin of the arctic ocean are rare core p189ar p45 collected in 405 m water depth on the beaufort sea slope west of the mackenzie river delta 70 33 03 n and 141 52 08 w is in close vertical proximity to the present day upper limit of modified atlantic water the 5 11 m core spans the interval between 6800 and 10 400 14 c yr b p with an 800 yr ocean reservoir correction the sediment is primarily silty clay with an average grain size of 9 the chronology is constrained by seven radiocarbon dates the rate of sediment accumulation averaged 1 35 mm yr stable isotopic data 18 o and 13 c were obtained on the polar planktonic foraminifera neogloboquadrina pachyderma s and the benthic infaunal species cassidulina neoteretis a distinct low 18 o event is captured in both the benthic and planktonic data at 10 000 14 c yr b p probably recording the glacial lake agassiz outburst flood associated with the north atlantic preboreal cold event the benthic foraminifera are dominated in the earliest holocene by c neoteretis a species associated with modified atlantic water masses this species decreases toward the core top with a marked environmental reversal occurring 7800 14 c yr b p possibly coincident with the northern hemisphere 8200 cal yr b p cold event

origin chemistry and flow of formation waters in the mississippian jurassic sedimentary succession in the west central part of the alberta basin canada abstract the flow and chemistry of formation waters was analyzed in the mississippian jurassic succession in the west central part of the alberta basin using publicly available standard chemical analyses of formation waters and drillstem test data collected by the petroleum industry in alberta the interpretation of the thoroughly culled hydrogeological data show that a transition between a southern and a northern basin scale flow system takes place in the study area in the southeastern half of the study area the mississippian jurassic hydrostratigraphic group represents a single continuous carbonate sandstone aquifer system consisting of the lower jurassic nordegg member the triassic montney formation the permian belloy formation and the mississippian stoddart and rundle groups the confining units are the competent fernie and exshaw banff aquitards at the top and base respectively the salinity of formation waters increases northwestwards from 50 to 150 g l while the bicarbonate content decreases in similar fashion from 3 to 0 5 g l the flow pattern based on hydraulic heads and chemical composition of formation waters indicate decreasing mixing of meteoric water carried northward in the southern basin scale long range system with heavier connate water present in the northern part of the study area in the center and in the northeast the permian and mississippian carbonates and the triassic montney and charlie lake halfway sandstones form individual aquifers separated by the intervening doig montney aquitard the flow in the charlie lake halfway and the permo mississippian aquifers is directed east northeastward from the deformation front into the overlying aquitards or discharging into the southern basin scale flow system respectively only in the montney aquifer the flow is directed inward south southwestward drawn into a local hydrocarbon saturated sink which is created by a higher rate of gas escape than of gas generation through a low permeability and capillary seal region the high salinity in the 130 150 g l range and low bicarbonate content 0 5 g l of formation waters in the northern part of the study area indicate a connate origin the relation of na ca cl br concentrations in the formation waters suggest that these waters initially originated as seawater that was altered to some degree by subaerial evaporation and dolomitization but halite dissolution probably is the main source of salinity the driving mechanism for the flow of these waters could be either tectonic expulsion from deep strata in the deformed part of the basin as suggested by the high salinity of these waters or topography driven meteoric recharge in the rocky mountains through a tortuous path unidentified as yet the integrated interpretation of flow and chemistry of formation water shows that mississippian jurassic formation waters in the deep west central parts of the alberta basin have been influenced less by mixing with meteoric water than was identified previously in the central southern and northern parts of the basin the main reasons for the isolation of relict mississippian jurassic formation waters in the deep alberta basin are effective confining aquitards and the fact that this area is influenced only marginally by mixing with meteoric water carried by a gravity driven flow system

geoarchaeological and paleohydrological evidence for a clovis age drought in north america and its bearing on extinction abstract at the murray springs clovis site in southeastern arizona stratigraphic and geomorphic evidence indicates that an abnormally low water table 10 900 yr b p was followed soon thereafter by a water table rise accompanied by the deposition of an algal mat the black mat that buried mammoth tracks clovis artifacts and a well this water table fluctuation correlates with pluvial lake fluctuations in the great basin during and immediately following clovis occupation of that region many elements of pleistocene megafauna in north america became extinct during the dry period oxygen isotope records show a marked decrease in 18o correlated with the younger dryas cold dry event of northern europe which ended 10 750 yr b p essentially the same time as the water table began to rise in southeastern arizona clovis hunters may have found large game animals easier prey when concentrated at water holes and under stress if so both climate and human predation contributed to pleistocene extinction in america

organic matter characterization in mixed hydrocarbon producing areas within the duvernay formation western canada sedimentary basin alberta this paper characterizes organic matter in the mixed hydrocarbon oil dry gas oil condensate producing areas of the late devonian duvernay formation in alberta canada by high resolution rockeval data n 246 and petrography n 35 at three drillhole locations locations a and c distal location b proximal to leduc reef respectively total organic carbon toc ranges from 0 15 622 wt at location a 0 43 820 wt at location b and 1 84 5 23 wt at location c with an overall median value of 3 42 wt s2 values range from 0 20 7 42 mg hc g of rock at location a 022 4 23 mg hc g of rock at location b and 1 68 5 04 mg hc g of rock at location c these results for samples from locations a b and c indicate that kerogen is type i to type ii the hydrogen index hi of these rocks is significantly lower 160 mg hc g toc than that of traditional oil producing source rocks of this age similar to 400 700 mg hc g toc at locations a and c t max lies within the oil window with a mean value of 459 degrees c at location b t max varies greatly between 434 and 488 degrees c between the oil and gas window with no observable association with sample depth vitrinite reflectance of samples ranges from 0 99 1 32 t max values do not correlate with vitrinite reflectance of the samples r 2 0 04 nor with depth r 2 0 4 suggesting that t max is not a reliable indicator of thermal maturity in this system low toc s2 high mineral carbon is associated with intervals of intergrown sparry calcite and pyrite in petrographic samples at location b organic matter within the duvernay formation was characterized as almost entirely solid bitumens with very minor inertinite 1 by volume the rockeval and petrographic observations suggest that secondary diagenetic effects are the cause for the mixed hydrocarbon signature rather than any spatial variation in depositional environment or thermal maturation regimes c 2016 elsevier b v all rights reserved

coal deposits in the front ranges and foothills of the canadian rocky mountains southern canadian cordillera abstract canada has the fifth largest inventory of coal resources in the world more than one third of canada s resources currently favourable for exploitation occur in the southern canadian rocky mountains with major deposits in the front ranges inner foothills and outer foothills physiographic provinces in the front ranges major deposits of metallurgical and thermal high volatile bituminous to semi anthracite coal occur in the late jurassic early cretaceous mist mountain formation in the inner foothills of northeastern british columbia and west central alberta significant resources of metallurgical and thermal medium and low volatile bituminous coal occur in early cretaceous strata of the gething aptian and gates albian formations in the outer foothills resources of thermal high volatile bituminous coal occur in late cretaceous and paleocene strata of the belly river campanian coalspur maastrichtian paleocene and paskapoo paleocene formations the major coal deposits of the front ranges and inner foothills accumulated within the coastal plains of the fernie and moosebar clearwater seas respectively shorelines prograded to the north and northeast into a foreland basin that evolved in advance of and in response to the evolving columbian orogen in the outer foothills coal deposits of the belly river formation originated within prograding coastal plains during the withdrawal of the pakowki sea the major coal deposits of the coalspur and paskapoo formations accumulated in the alluvial plain environments of the foreland basin during the laramide orogeny coal measures of the southern canadian rocky mountains were variably folded and faulted during the laramide orogeny late cretaceous eocene structural deformation has significantly affected the mineability and quality of the coals many of the coal seams are sheared structurally thickened or thinned and repeated by thrust faults or truncated by normal faults shearing of the seams in adjacent hanging and footwall strata has led locally to pronounced oxidation resulting in weak coal pillars and roofs in underground mines faulting and folding has partitioned many coal deposits into discrete structural domains of varying style and complexity each of which can present a unique challenge in designing optimum coal extraction methods the variation in coal rank in the southern canadian rocky mountains mainly reflects the preorogenic pre laramide depth of burial in some areas however there is evidence for syn and post orogenic coalification resulting from the emplacement of thick overthrust sheets and or deposition of thick tertiary molasse most of which has been subsequently eroded with few exceptions coals of the southern canadian rocky mountains are characterized by low sulphur contents

timing of organic maturation coalification relative to thrust faulting in the southeastern canadian cordillera abstract in order to access the effects if any of overthrusting tectonic burial on levels of organic maturation coalification detailed vitrinite reflectance profiles were constructed for 11 deep boreholes that penetrated stacked thrust sheets of mesozoic and paleozoic strata in the southeastern canadian cordillera recognition of the timing and degree of maturation resulting from emplacement of thrust sheets is largely dependent on the accuracy with which the preorogenic level of maturation of the strata is known the vitrinite reflectance profiles of several boreholes suggest that a significant component of organic maturation coalification postdates emplacement of overthrust sheets and have resulted from tectonic burial for other boreholes however the maturation profiles are ambiguous and suggest that postorogenic maturation if any was insufficient to overprint preorogenic levels of maturity maturity levels and reflectance gradients of mesozoic strata in general are lower in the southern part of the southeastern cordillera than in the northern part which imply higher paleoheat flow in the north

geothermal gradients hydrodynamics and hydrocarbon occurrences alberta canada using coal rank data and the demonstrated genetic link between the present hydrodynamic regime and geothermal gradient pattern it is possible to reconstruct the geothermal history of alberta over the past 60 m y palinspastic adjustment for tectonic compression caused by the major laramide thrusting shows that the predeformation isoreflectance lines increased logarithmically with depth in the late paleocene the geothermal gradient was about 23 c km 1 25 f 100 ft in the eastern alberta plains compared to about 30 c km 1 65 f 100 ft in the western alberta plains a regional trend opposite to the post laramide trends reconstruction of the early eocene surface indicates western uplands with geothermal gradients as low as 21 c km 1 15 f 00 ft and eastern lowlands with geothermal gradients of 27 c km 1 5 f 100 ft compared to the present situation this represents an enhanced topographic surface and a subdued geothermal gradient pattern the genetic relations of topography water table elevation hydrodynamic regime and geothermal gradient pattern in both the early eocene and the present conform to a model developed for any compacted sedimentary basin with subaerial relief in this model on a regional scale high topographic areas have high water table elevations with correspondingly high potentiometric surfaces these areas control the regional recharge of cold meteoric water and hence have low geothermal gradients areas of medium elevation exhibit regional lateral flow and intermediate geothermal gradients regional topographic lows correspond with low potentiometric surfaces and the regional discharge of warm formation waters from deep in the basin results in high geothermal gradients local topographic featur s cause perturbations in this picture study of both the regional pattern and fine detail of the early eocene and present topographic surfaces and geothermal gradient patterns shows the validity of the model the result of the second laramide orogenic pulse was therefore to reverse the geothermal gradient pattern resulting mainly from compaction flow and to impose a topographically controlled hydrodynamic regime with flow in the same direction but with a 9 c km 0 5 f 100 ft decreased geothermal gradient in western alberta and a 4 c km 0 2 f 100 ft increased geothermal gradient in eastern alberta as erosion proceeded during the tertiary the entire alberta basin warmed up until the present temperature regime was attained study of some major hydrocarbon occurrences shows a genetic link between the hydrocarbon occurrence and the present fluid regime which itself is controlled by the present topography for at least the significant upper cretaceous shallow gas reserves in southeastern alberta however their position may already have been determined as early as the beginning of the eocene by the topographic surface at that time therefore the extent to which the present topographic surface is responsible for hydrocarbon accumulation through gravity induced cross formational flow remains unknown because this process was operative as long ago as the early eocene what does not ap ear to be in doubt is the fact that gravity induced cross formational flow does control the hydrodynamic regime which in turn influences the geothermal gradient pattern and the accumulation of hydrocarbons

an analysis of the molluscs from an ipswichian interglacial river channel deposit at maxey cambridgeshire england a freshwater and land molluscan assemblage from an ipswichian stream channel at maxey cambridgeshire is discussed the presence of belgrandia marginata and vallonia enniensis suggests that summer temperatures may have been somewhat warmer in the ipswichian period the assemblage represents the silting processes under relatively quiet water conditions possibly in a side channel or backwater of a meandering river system

evidence of widespread wildfires in coal seams from the middle jurassic of northwest china and its impact on paleoclimate abstract today wildfire is an important disturbance in many continental ecosystems and it is assumed that with ongoing climate changes the frequencies and impacts of wildfires will increase in many regions one way to obtain information about the potential long term influences of wildfires on ecosystems and the climate system itself is to study palaeo wildfires a total of 140 jurassic samples including 122 coal samples and 18 rock samples from roof and floor of coal seams were collected from 4 coalfields in northwestern china the samples were analyzed by macropetrography microscopy scanning electron microscopy gas chromatography and gas chromatography mass spectrometry to study the evidences of wildfires and their impact on the paleoclimate high contents of pyrogenic inertinites charcoal natural char and natural coke particles observed in the samples which indicate that widespread wildfire events occurred in the early middle jurassic in all over northwestern china additionally high molecular weight polycyclic aromatic hydrocarbons were detected in the coal samples these aromatic compounds were formed under high temperature and provide further evidence of wildfires according to a carbon emission model for modern forest fires the total carbon and gas emissions from wildfires in peat swamps of the middle jurassic in northwest china were calculated by the data from 21 575 coal samples of number of 1567 drill core samples the total carbon released from peat swamp forest wildfires was at least 1207 gt corresponding to emissions of co2 co and ch4 of 1926 gt 163 gt and 8 8 gt respectively the huge amount of co2 released by forest fires in the peat swamp systems of the middle jurassic in northwestern china alone was equivalent to 64 20 of the total co2 in the atmosphere at present 3000gt the large amounts of greenhouse gases released by wildfires must have led to long term changes in the atmospheric composition and have caused global warming which could have the reason of affected the paleoclimate

the detection of weathering in coal by petrographic rheologic and chemical methods abstract this study examines petrographic rheologic proximate and ultimate analyses techniques to investigate the effects of natural weathering on coal the applicability of such tests to both the detection of weathering and to the prediction of the properties of a fresh coal based upon analyses of a weathered sample is discussed rheologic parameters and a petrographic staining technique showed the most sensitive response to weathering the latter test is considered the most suitable of these for the detection of weathering as it is independent of prior knowledge of the properties of the fresh coal and of the petrographic composition a petrographic approach is also considered most suitable for estimation of fresh coal characteristics from weathered samples rank may be closely approximated and petrographic type determined microscopically even on highly weathered samples and these two parameters may be used to estimate properties such as volatile matter calorific value and dilatation minor modification should be made to vitrinite reflectance measurements according to the degree of weathering as revealed by selective staining

colliery and surface hazards through coal pyrite oxidation pennsylvanian sydney coalfield nova scotia canada pennsylvanian sydney coalfield nova scotia canada is submarine as coal mining took place beneath the north atlantic ocean all collieries were shut down in 2001 the coal was on average sulfurous pyrite rich ca 5 total sulfur which on exposure to the atmosphere oxidized rapidly to form definite sequences of secondary hydrated sulfate minerals thus the collieries were veritable laboratories for studying in situ hydrated sulfate paragenesis in roof rocks coal floor rocks based on these studies and on direct observations over several years a conceptual model of roof rock instability is proposed this model explains rock falls in tunnels slopes during once operating coal mines short term hazard as well as surface subsidence in land areas undermined long ago by room and pillar methods in the sydney coalfield long term hazard the model invites testing in other pennsylvanian coalfields that have similar geochemical conditions and employ similar mining methods

possible controls of hydrogeological and stress regimes on the producibility of coalbed methane in upper cretaceous tertiary strata of the alberta basin canada the coalbed methane potential and producibility of any coal bearing strata are strongly affected by the hydrogeological regime of formation waters and by coal permeability which in turn depends on the effective stress regime of the coals peat that accumulated in the alberta basin during the late cretaceous and early tertiary led to the formation of coal deposits that may contain significant coalbed methane resources the flow of formation waters plays an important role in the maintenance and producibility of this resource the present day flow is driven by gravity topography and erosional rebound and is controlled by rock permeability and the presence of gas saturated sandstones the estimated gas in place in the tertiary upper cretaceous coals decreases significantly with stratigraphic age ranging between less than 2 bcf mi2 in the lower coal zones and 12 bcf mi2 in the uppermost coals the gas content especially of the deeper coals is lower than would be expected for the corresponding coal rank and burial depth most likely because the underpressuring has caused the release of gas from the coals and accumulation in adjacent sands the shallow coals although of low rank may contain important amounts of late stage biogenic methane the salinity of formation water in shallow coal seams where the flow is driven by topography is low generally less than 1500 mg l although in places it reaches 3000 5000 mg l the salinity of formation water in the deeper underpressured strata in the west central part of the basin is significantly higher reaching 18 000 mg l this affects treatment and or disposal strategies with regard to the water produced concurrent to coalbed methane the producibility of this resource depends on coal permeability which decreases west southwestward with increasing burial depth from the order of several darcys in the shallow zones to millidarcys in the deep zones the minimum effective stress which affects coal permeability by closing fractures increases west southwestward from zero at the erosional edge of these strata to approximately 20 mpa near the rocky mountain deformation front fractures including those in coal seams will generally be vertical and will propagate on a southwest northeast axis along the direction of the maximum horizontal stress in a direction generally perpendicular to the rocky mountain deformation front considering the hydrogeological and stress regimes in conjunction with estimations of the gas content in coals the region with probably good coalbed methane potential and producibility are the ardley coal zone in the scollard formation and maybe to a lesser extent the coal zones of the stratigraphically deeper edmonton and belly river groups along their respective subcrop in central and southern alberta the deep edmonton and belly river strata in western and central alberta have most likely a reduced coalbed methane potential as a result of lower gas content and of low permeability these regional considerations need to be applied against local studies of coal thickness rank permeability and gas content to identify the best targets for coalbed methane exploration and production

source rock potential and thermal maturity of lower cretaceous strata monkman pass area british columbia shale and coals from 1 2 km of core through most of the preserved lower cretaceous in western canada were analyzed for source rock potential and maturation level although much of the core lies within the oil window none of the formations are notably oil prone oxidizing bottom conditions and the large predominance of terrestrial organic matter om in the relatively nearshore depositional setting of the marine sediments have led to the dominance of terrestrial om throughout this sequence of rocks including the marine shales as such mostly gas will be or has been generated the nonmarine minnes group and gething and gates formations average 2 7 6 3 and 5 2 total organic carbon toc respectively with fair to very good gas source potential the nonmarine boulder creek formation contains 1 1 toc and has poor source rock potential due to the presence of several thick paleosols the marine moosebar hulcross and basal shaftesbury formations contain 1 5 1 7 and 1 5 average toc contents respectively and have poor to fair source rock potential these marine sediments which may have generated limited amounts of oil show a progressive decrease of hydrogen index hi with depth due to thermal degradation with increased burial hi for nonmarine sediments remains constant with depth the marine sediments contain mostly type iii kerogen with lesser amounts of thermally degraded type ii kerogen vitrinite reflectance increases systematically with depth from 0 94 to 1 5 romax tmax values correspond well with vitr nite reflectance although tmax values for marine sediments increase more slowly with increasing maturation than nonmarine sediments

late pleistocene and holocene meltwater events in the western arctic ocean accelerator mass spectrometer 14 c dated stable isotope data from neogloboquadrina pachyerma in cores raised from the mendeleyev ridge and slope provide evidence for significant influx of meltwater to the western arctic ocean during the early part of marine oxygen isotope stage 1 ois 1 and during several intervals within ois 3 the strongest ois 3 meltwater event occurred before ca 45 ka conventional radiocarbon age and was probably related to the deglaciation at the beginning of ois 3 major meltwater input to the western arctic ocean during the last deglaciation coincides closely with the maximum rate of global sea level rise as determined from the barbados sea level record demonstrating a strong link between the global record and changes in the central arctic ocean ois 2 which includes the last glacial maximum is very condensed or absent in the cores abundance and 13 c values for n pachyderma in the middle part of ois 3 are similar to modern values indicating high productivity and seasonal ice free areas along the arctic margin at that time these records indicate that the arctic ocean was a source of heat and moisture to the northern polar atmosphere during parts of ois 3

data for enhanced deposition of coal fragments at the chukchi margin western arctic ocean implications for deglacial drainage history from the laurentide ice sheet abstract distribution and composition of coarse particles 250 m were investigated in 13 sediment cores from the chukchi margin western arctic ocean petrographic clast identification is supplemented by xrf core scanning eds analysis of coal fragments and ams 14c dating of planktic foraminifera for age control coal debris distribution is also investigated in surface sediments of the study region for provenance interpretation the sediment core study focuses on the interval between the last glacial maximum and the holocene for constraining provenance and timing of the deglacial discharge we find that this interval is characterized by a distinct enrichment in sedimentary rock fragments including coal comparison with longer stratigraphic records indicates that this composition is unique for the time interval since at least maine isotope stage 5 based on the timing interpreted provenance and geographic distribution of the coal enrichment we conclude that the most likely primary source was the deglacial discharge from the mackenzie drainage basin of the laurentide ice sheet lis the identified coal bearing layer also expressed in the xrf sulfur record can be thus used as a stratigraphic marker for the lis discharge to the arctic ocean during the last deglaciation

compression cuticle relationship of seed ferns insights from liquid solid states ftir late palaeozoic early mesozoic canada spain argentina abstract cuticles have been macerated from suitably preserved compressed fossil foliage by schulze s process for the past 150 years whereas the physical biochemical relationship between the coalified layer with preserved cuticle as a unit has hardly been investigated although they provide complementary information this relationship is conceptualized by an analogue model of the anatomy of an extant leaf vitrinite mesophyll cuticle biomacropolymer compression alkaline solutions from schulze s process as a proxy for the vitrinite are studied by means of liquid solid states fourier transform infrared spectroscopy ftir in addition cuticle free coalified layers and fossilized cuticles of seed ferns mainly from canada spain and argentina of late pennsylvanian late triassic age are included in the study sample infrared data of cuticle and alkaline solutions differ which is primarily contingent on the mesophyll biomacropolymer characteristics the compression records two pathways of organic matter transformation one is the vitrinized component that reflects the diagenetic post diagenetic coalification history parallel with the evolution of the associated coal seam the other is the cuticle that reflects the sum total of evolutionary pathway of the biomacropolymer its monomeric or polymeric fragmentation though factors promoting preservation include entombing clay minerals and lower ph conditions caution is advised when interpreting liquid state based ftir data as some ir signals may have resulted from the interaction of schulze s process with the cuticular biochemistry a biochemical study course for taphonomy is suggested as fossilized cuticles cuticle free coalified layers and compressions are responses to shared physicogeochemical factors

freshwater input and abrupt deglacial climate change in the north atlantic greenland ice core records indicate that the last deglaciation 7 21 ka was punctuated by numerous abrupt climate reversals involving temperature changes of up to 5 10oc within decades however the cause behind many of these events is uncertain a likely candidate may have been the input of deglacial meltwater from the laurentide ice sheet lis to the high latitude north atlantic which disrupted ocean circulation and triggered cooling yet the direct evidence of meltwater input for many of these event has so far remained undetected in this study we use the geochemistry paired mg ca 18 o of planktonic foraminifera from a sediment core south of iceland to reconstruct the input of freshwater to the northern north atlantic during abrupt deglacial climate change our record can be placed on the same timescale as ice cores and therefore provides a direct comparison between the timing of freshwater input and climate variability meltwater events coincide with the onset of numerous cold intervals including the older dryas 14 0 ka two events during the allerod at 13 1 and 13 6 ka the younger dryas 12 9 ka and the 8 2 ka event supporting a causal link between these abrupt climate changes and meltwater input during the bolling allerod warm interval we find that periods of warming are associated with an increased meltwater flux to the northern north atlantic which in turn induces abrupt cooling a cessation in meltwater input and eventual climate recovery this implies that feedback between climate and meltwater input produced a highly variable climate a comparison to published data sets suggests that this feedback likely included fluctuations in the southern margin of the lis causing rerouting of lis meltwater between southern and eastern drainage outlets as proposed by clark et al science 2001 v293 283 287

the use of ostracods from marginal marine brackish waters as bioindicators of modern and quaternary environmental change abstract ostracoda microscopic aquatic crustacea from brackish waters have a great potential for ecological monitoring and palaeoenvironmental analyses in highly variable environments this has been proven in many articles during recent decades but their potential has yet to be fully developed or utilised the analysis of ostracod assemblage composition species distributions eco phenotypic variability and the analysis of stable isotopes and trace elements in ostracod shells provide valuable information on present and past water salinity temperature and chemistry hydrodynamic conditions substrate characteristics climate sea level variations oxygen and nutrient availability this article provides an overview on the application of ostracods from brackish waters for palaeoenvironmental reconstruction in the quaternary and for environmental studies in present day environments

a paleoclimatic and paleoatmospheric record from peatlands accumulating during the cretaceous paleogene boundary event western interior basin canada petrological and 13 c analyses were undertaken on contiguous specimens of coal and intercalated minor organic rich clastic sediments collected from coal seams spanning the cretaceous paleogene boundary in the alberta and saskatchewan portions of the western interior basin the generally high smectite content of the coal suggests that the original mires were largely small disconnected and rheotrophic readily receiving abundant waterborne detrital clastic material of largely volcanic origin nevertheless using the distinctive claystone that marks the cretaceous paleogene boundary as a regional datum it is possible to correlate cycles in the vitrinite and inertinite composition of the coals over 500 km estimates of peat accumulation rates suggest that the cycles in vitrinite and inertinite composition represent regional cyclic fluctuations in wildfire and oxidation of the peatlands and overlying canopy at a frequency of hundreds to thousands of years the likely causes of these fluctuations were cyclic regional scale changes in temperature the cretaceous paleogene boundary event occurred early during a phase of gradually increasing temperature and or decreasing rainfall but peak wildfire and desiccation of peat occurred up to 14 000 yr later than the cretaceous paleogene boundary and the mires did not experience significant water stress in the immediate aftermath of the extinction event a persistent 1 5 3 0 negative 13 c excursion occurs across the cretaceous paleogene boundary but it cannot be readily separated from four further negative excursions later in the earliest danian the negative carbon isotope excursion linked to the cretaceous paleogene boundary began a few hundred years before the event itself and recovery occurred within 21 k y and possibly in as little as just a few thousand years consistent with recently calibrated shallow marine 13 c records hence the atmospheric and surface ocean carbon pools were coupled at this time the absence of evidence for catastrophic change in the climatic regime at the time of the cretaceous paleogene extinction in these mires supports the notion that the negative shift in atmospheric 13 c was brought about by changes in the 13 c composition of the surface ocean this is consistent with the greater magnitude of extinction experienced by marine fauna relative to the terrestrial realm

thermal maturity of the upper triassic middle jurassic shemshak group alborz range northern iran based on organic petrography geochemistry and basin modelling implications for source rock evaluation and petroleum exploration organic petrography and geochemical analyses have been carried out on shales carbonaceous shales and coals of the shemshak group upper triassic middle jurassic from 15 localities along the alborz range of northern iran thermal maturity of organic matter om has been investigated using vitrinite reflectance rock eval pyrolysis and elemental analysis of kerogen reflectance of autochthonous vitrinite varies from 0 6 to 2 2 indicating thermally early mature to over mature om in the shemshak group in agreement with other maturity parameters used the shales of the shemshak group are characterized by poor to high residual organic carbon contents 0 13 to 5 84 and the presence of hydrogen depleted om predominantly as a consequence of oxidation of om at the time of deposition and the hydrogen loss during petroleum generation according to light reflected microscopy results vitrinite vitrinite like macerals are dominant in the kerogen concentrates from the shaly facies the coals and carbonaceous shales of the shemshak group show a wide range in organic carbon concentration 3 5 to 88 6 and composition inertinite and vitrinite rich types and thereby different petroleum potentials thermal modelling results suggest that low to moderate palaeo heat flow ranging from 47 to 79 mw m 2 57 mw m 2 on average affected the central eastern alborz basin during tertiary time the time of maximum burial of the shemshak group the maximum temperature that induced om maturation of the shemshak group seems to be related to its deep burial rather than to a very strong heat flow related to an uppermost triassic liassic rifting the interval of petroleum generation in the most deeply buried part of the shemshak group i e tazareh section corresponds to middle jurassic early cretaceous times exhumation of the alborz range during late neogene time especially along the axis of the central eastern alborz where maximum vitrinite reflectance values are recorded probably destroyed possible petroleum accumulations however on the northern flank of the central eastern alborz preservation of petroleum accumulations may be expected the northern part of the basin therefore seems the best target for petroleum exploration

transport and concentration of detrital gold in foreland basins abstract economic concentrations of detrital gold are rare in young foreland basins due to paucity of significant gold sources and a paucity of sediment recycling processes during filling of the foreland basin gold shed into the foreland basins is typically widely dispersed in an overwhelming volume of immature basin fill detritus of no economic significance in the actively forming canterbury basin of new zealand minor gold concentration occurs at the mountain front in the bed of the rakaia river and 60 km downstream on beaches and the crest of foredunes at the river mouth the cretaceous tertiary denver and western canada basins in north america also have minor gold concentrations at the mountain front and minor gold dispersal into the basin tectonic quiescence in the middle tertiary in the denver basin kept gold within 20 km of the mountain front where renewed uplift in late tertiary caused minor economic concentrations to form in modern streams gold has been transported ca 200 km across the western canada basin by progressive recycling of gravel during slow ca 10 to 50 m ma middle tertiary recent regional uplift and tilting but little concentration has occurred development of significant placers in a foreland basin the generally accepted setting for the witwatersrand au u palaeoplacers appears to require specific tectonic conditions during and or after basin evolution to drive the sedimentary recycling necessary for significant placer development such tectonic conditions have not occurred in an any of the three young foreland basins examined in this study

coupled fluid flow heat and mass transport and erosion in the alberta basin implications for the origin of the athabasca oil sands regional topography driven flow systems related to laramide tectonic rebound were simulated using two dimensional coupled fluid flow heat transport and solute transport numerical models to replicate present formation water salinity and temperature distributions and investigate the accumulation of the athabasca oil sands previous modelling of this system was replicated and it predicted repeated replacement of all basin formation water with freshwater during deposition of the oil sands due to high permeabilities to match present alberta basin temperature and salinity distributions model hydrostratigraphy permeabilities and heat fluxes were adjusted this revised model conducts fluids along the mannville aquifer rather than the upper devonian aquifer and replicates present salinity distributions assuming instantaneous uplift around 60 ma fluid fluxes in principal aquifers decrease by two orders of magnitude using new permeabilities resulting in primarily conductive heat transport thus genesis

stable isotope geochemistry of syntectonic veins in paleozoic carbonate rocks in the livingstone range anticlinorium and their significance to the thermal and fluid evolution of the southern canadian foreland thrust and fold belt the livingstone range anticlinorium lra marks a major hanging wall ramp where the livingstone thrust cuts approximately 1000 m 3281 ft between regional decollement in the upper part of the devonian palliser formation and the jurassic fernie formation prethrusting and folding jasper fluorite sphalerite veins with halos of altered dolomitic host rock with high 87sr 86sr ratios 0 7094 0 7101 relative to most paleozoic carbonate rocks 0 7081 0 7091 record percolation of fluids along basement faults that may also have contributed anomalously radiogenic strontium to diagenetically altered paleozoic carbonate rocks throughout the western canada sedimentary basin fluid flow that occurred during thrust propagation folding is recorded by dolomite calcite veins with 18o values that are similar to those of host rocks 7 92 to 1 08 peedee belemnite anomalously high equilibrium temperatures 250 50c as determined by oxygen isotope thermometry and slightly higher 87sr 86sr ratios relative to adjacent host rocks indicate that they formed from formation fluids and hot basement fluids in a rock dominated system calcite veins with very low 18o values 18 to 9 precipitated along faults that were active while the lra was transported eastward by underlying thrust faults uplifted and rapidly cooled by infiltrating meteoric water thrusting created heating in the foreland basin ahead of the deformation because of the influx of thick insulating foreland basin sediments causing thermal maturation of hydrocarbons as thrusting deformation advanced through the rocks infiltrating meteoric waters cooled the rocks and hydrocarbon maturation stopped structural traps accumulated hydrocarbons only if they were juxtaposed over both thermally favorable and hydrocarbon favorable source rocks

arctic ocean glacial history while there are numerous hypotheses concerning glacial interglacial environmental and climatic regime shifts in the arctic ocean a holistic view on the northern hemisphere s late quaternary ice sh

rhenium osmium geochronology and oil source correlation of the duvernay petroleum system western canada sedimentary basin implications for the application of the rhenium osmium geochronometer to petroleum systems the re os geochronometer has been applied to many petroleum systems worldwide however it is debated if the re os systematics in petroleum actually record the timing of oil generation here we investigate the re os isotope systematics of the duvernay petroleum system in the western canada sedimentary basin which has been shown to be a relatively simple petroleum system that is associated with oil generated during the late cretaceous early eocene laramide orogeny from a single source the organic geochemistry of the duvernay oils pristane phytane ratios of 1 5 smooth homohopane profile c29 c27 c28 regular sterane distribution and predominance of diasteranes over regular steranes strongly suggests the oil source to be that of type i ii marine organic matter of the upper devonian duvernay formation the asphaltene fraction re os isotope data of the duvernay oil yield an age of 66 31 ma which is in excellent agreement with the timing of the main stage hydrocarbon generation of the duvernay formation based on basin models further the similarity between the 187os 188os compositions of the duvernay formation source rock 0 46 1 48 and the oil 0 55 1 06 at the time of oil generation supports the hypothesis that the 187os 188os composition of an oil is inherited from the source unit at the time of oil generation and therefore shows no or limited influence from interaction with basin fluids this study supports that the re os isotope systematics of an oil can yield the timing of oil generation and be used to trace its source

functional groups in a single pteridosperm species variability and circumscription pennsylvanian nova scotia canada abstract multiple foliar specimens of the late pennsylvanian fossil pteridosperm gymnosperm alethopteris zeilleri ragot wagner were collected from one restricted stratigraphical horizon in the canadian sydney coalfield variability of functional group distribution using ftir technique was studied in compressions adaxial versus abaxial cuticles and in unseparated cuticles as a function of maceration time from 48 to 168 h the results obtained document spectral variability that could be expected within specimens of one species for example ch 2 ch 3 and al ox ratios can differ by as much as 20 of the values moreover the experiments performed confirm that by using a previously established maceration protocol long maceration periods do not bias ftir spectra in terms of oxygenation overprinting the inference that this cuticle is robust under the given diagenetic level probably reflects a reassuring degree of chemical fidelity of the pennsylvanian plant to support carboniferous chemotaxonomic observations

widespread multi source glacial erosion on the chukchi margin arctic ocean abstract multibeam bathymetry and sub bottom profiler data acquired in 2011 from r v marcus langseth in a broad grid over the chukchi sea margin reveal multiple glacigenic features on the top and slopes of the outer chukchi shelf rise and adjacent borderland glacial lineations record a complex pattern of erosion likely formed by both local glaciation and far traveled ice shelves streams sourced from the laurentide and possibly east siberian ice sheets multiple till units and stacked debris flows indicate recurrent glacial grounding events composite till wedges of several hundred meters thick extend the shelf edge by 10 20 km in places distribution of ice marginal features on the chukchi rise suggests stepwise deglacial retreat towards the shelf backing up the broad bathymetric trough at the eastern side of the rise glacigenic features other than extensive iceberg scouring cannot be identified above 350 m depth and no glacigenic bedforms are present on the current swept shallow shelf despite the resulting uncertainty with the southern extent of the glaciation the data suggest a widespread grounded ice presence on the northern chukchi shelf which makes it an important previously underestimated component of the arctic paleo glacial system

land sea correlations in the pleistocene based on isoleucine epimerization in non marine molluscs the correlation between the oxygen isotope stratigraphy of the oceans and continental stratigraphic records is one of the main challenges for quaternary research most continental classifications however are based on techniques and hypotheses that predate recent advances nevertheless the deep sea oxygen isotope global stratigraphic framework has been extended to the continents by means of some long sequences1 but these are exceptional and regional geology is unsatisfactorily classified for correlation with the oxygen isotope signal because successive geological events produced similar evidence homotaxis geochronometric dating is essential for correlation but available methods are highly site regional or sample specific fortunately non marine molluscs are ubiquitous in time and space and here we use the time dependent epimerization of l isoleucine in these fossils to subdivide the pleistocene of the british isles and to identify more events than recognized by the existing classification2 by calibrating the relative aminostratigraphic scale with independent dating methods we have set up a geochronology which is the basis for land sea correlations back to oxygen isotope stage 15

climatic control on quaternary fluvial sedimentology of a fenland basin river england understanding and interpreting climate response from ancient fluvial deposits requires a combined approach of detailed sedimentological description and interpretation local climate proxies and the accurate comparison of these sequences with further independent climate records application of these multiple lines of evidence is particularly effective in the quaternary period where higher resolution and more detailed palaeoenvironmental reconstruction are possible this paper presents results from a devensian weichselian age sequence in northern fenland england that integrates these approaches detailed sedimentological description has identified three fluvial facies associations overlain by a period of ice wedge cast formation fossil plant and coleopteran material within these sediments have been studied to provide palaeoenvironmental reconstructions for the local landscape including quantitative temperature estimates using the mutual climatic range method on fossil coleoptera in addition joint application of radiocarbon and optically stimulated luminescence osl dating allows this sequence to be compared with the stacked marine isotope record although dates do not agree well at the limit of the radiocarbon technique sedimentological interpretations palaeoenvironments and global ice volume variations a proxy for climatic severity are all in agreement and show clearly how the river nene responded to subtle changes in climate and vegetation cover during the devensian weichselian stage the level of detail possible in this reconstruction shows the importance of this approach in understanding fluvial response to past climate changes

isotopic fingerprints of shallow gases in the western canadian sedimentary basin tools for remediation of leaking heavy oil wells abstract thousands of wells have been drilled in northeastern alberta and adjacent saskatchewan in order to develop the heavy oil reservoirs of the lower cretaceous mannville group in a large number of these wells vertical migration of gas from unknown sources to the surface via well casings and surrounding soils represents a serious environmental problem mud samples from new wells drilled in the area were collected at approximately 50 m intervals from the surface to the completion depth and the gases contained within the muds mud gases were analyzed for 13c 12c composition gases from the various mannville group sands do not show unique isotopic signatures they comprise bacterial methane 13cc1 70 to 60 pdb with trace c2 components that are residues from biodegradation processes gases from each of the overlying upper cretaceous colorado group shale units are however isotopically distinct the 13c of methanes in the shales have values equivalent to those within the mannville sands but the 13c of the c2 components are unambiguously different c2 gases from the shallower colorado shales are incipient thermal gases and fit the isotopic maturity diagram of james a t 1983 aapg bull 67 1176 1191 and also of chung h m gormly j r squires r m 1988 chem geol 71 97 103 we believe these gases may include the most immature suite of thermogenic gases reported 13cc2 63 to 32 13cc3 42 to 22 13cnc4 37 to 23 carbon isotope fingerprints from mud gases are used to identify specific source depths of migrated gases comparisons between the isotopic characteristics of the shallow gases and the migrated gases collected near surface infer that most of the migrated gases are actually generated in the colorado group shales and not the mannville sands in which the wells were completed the ability to estimate the source depth of the migrated gases greatly aids remediation of leaking wells within the western canadian sedimentary basin wcsb

heinrich events massive late pleistocene detritus layers of the north atlantic and their global climate imprint 1 millennial climate oscillations of the glacial interval are interrupted by extreme events the so called heinrich events of the north atlantic their near global footprint is a testament to coherent interactions among earth s atmosphere oceans and cryosphere on millennial timescales heinrich detritus appears to have been derived from the region around hudson strait it was deposited over approximately 500 250 years several mechanisms have been proposed for the origin of the layers binge purge cycle of the laurentide ice sheet jokulhlaup activity from a hudson bay lake and an ice shelf buildup collapse fed by hudson strait to determine the origin of the heinrich events i recommend 1 further studies of the timing and duration of the events 2 further sedimentology study near the hudson strait and 3 greater spatial and temporal resolution studies of the layers as well as their precursory intervals studies of previous glacial intervals may also provide important constraints

glacial shortcut of arctic sea ice transport due to the lack of data the extent thickness and drift patterns of sea ice and icebergs in the glacial arctic remains poorly constrained earlier studies are contradictory proposing either a cessation of the marine cryosphere or an ice drift system operating like present day here we examine the marine arctic cryosphere during the last glacial maximum lgm using a high resolution regional ocean sea ice model whereas modern sea ice in the western arctic basin can circulate in the beaufort gyre for decades our model studies present an extreme shortcut of glacial ice drift in more detail our results show a clockwise sea ice drift in the western arctic basin that merges into a direct trans arctic path towards fram strait this is consistent with dated ice plow marks on the seafloor which show the orientation of iceberg drift in this direction also ice transported iron oxide grains deposited in fram strait can be matched by their chemical composition to similar grains found in potential sources from the entire circum arctic the model results indicate that the pattern of arctic sea ice drift during the lgm is established by wind fields and seems to be a general feature of the glacial ocean our model results do not indicate a cessation in ice drift during the lgm