observations on the role of the bernice coal field sullivan county pennsylvania anthracites in the development of coalification theories in the appalachians abstract the bernice coal field sullivan county pennsylvania contains anthracite rank coal in relatively unfolded strata that setting along with a misinterpretation of the significance of apparent rank anomalies led to examples from the bernice coal field being used in the development of coalification theories in the late 1800 s and early 1900 s the evidence available was used to justify both theories of thrust pressure coalification and rank variation due to original differences in the peat or peat accumulation processes as opposed to thermal metamorphism

a geochemical study of oil migration at source rock reservoir contacts stable isotopes abstract whereas organic geochemical analyses of oils and potential source rocks have enabled correlations to be drawn and have been utilized to suggest modes of migration only limited data has been published relating a known source rock in contact with an oil filled reservoir this paper presents initial results from the examination of an approximately 100 m continuous core through the kimmeridge shale of the north sea the variability in extractable source rock hydrocarbon contents kerogen toc asphaltene and their carbon isotopic contents are documented nitrogen isotopic content of kerogens and asphaltenes as well as kerogen and asphaltene ton are relatively constant carbon isotopic compositions of kerogen extractable hydrocarbons and asphaltenes covaried significantly as did nitrogen isotopic compositions of kerogen and asphaltenes average isotopic compositions of the asphaltene free extracts and asphaltenes were nearly identical to the oil in the primary reservoir small chemical differences are noted among extracts

onset conditions for equatorial spread f the problem of day to day variability in the occurrence of equatorial spread f esf is addressed using multidiagnostic observations and semiempirical modeling the observational results are derived from a two night case study of esf onset conditions observed at kwajalein atoll marshall islands using the altair incoherent scatter radar and all sky optical imaging techniques the major difference between nights when esf instabilities did not occur august 14 1988 and did occur august 15 1988 in the kwajalein sector was that the northern meridional gradient of 6300 a airglow was reduced on the night of limited esf activity modeling results suggest that this unusual airglow pattern is due to equatorward neutral winds previous researchers have shown that transequatorial thermospheric winds can exert a control over esf seasonal and longitudinal occurrence patterns by inhibiting rayleigh taylor instability growth rates we present evidence to suggest that this picture can be extended to far shorter time scales namely that surges in transequatorial winds acting over characteristic times of a few hours to a day can result in a stabilizing influence upon irregularity growth rates the seemingly capricious nature of esf onset may thus be controlled in part by the inherent variability of low latitude thermospheric winds

geologic controls on thermal maturity patterns in pennsylvanian coal bearing rocks in the appalachian basin thermal maturation patterns of pennsylvanian strata in the appalachian basin were determined by compiling and contouring published and unpublished vitrinite reflectance vr measurements vr isograd values range from 0 6 in eastern ohio and eastern kentucky western side of the east kentucky coal field to greater than 5 5 in eastern pennsylvania southern anthracite field schuylkill county corresponding to astm coal rank classes of high volatile c bituminous to meta anthracite vr isograds show that thermal maturity of pennsylvanian coals generally increases from west to east across the basin the isograds patterns which are indicative of maximum temperatures during burial can be explained by variations in paleodepth of burial paleogeothermal gradient or a combination of both however there are at least four areas of unusually high rank coal in the appalachian basin that depart from the regional trends and are difficult to explain by depth of burial alone 1 a west northwestward salient centered in southwestern pennsylvania 2 an elliptically shaped northeast trending area centered in southern west virginia and western virginia 3 the eastern part of black warrior coal field alabama and 4 the pennsylvania anthracite region in eastern pennsylvania high rank excursions in southwest pennsylvania the black warrior coal field and the pennsylvania anthracite region are interpreted here to represent areas of higher paleo heat flow related to syntectonic movement of hot fluids towards the foreland associated with alleghanian deformation in addition to higher heat flow from fluids the pennsylvania anthracite region also experienced greater depth of burial the high rank excursion in southwest virginia was probably primarily controlled by overburden thickness but may also have been influenced by higher geothermal gradients

late permian age of nh4 bearing illite in anthracite from eastern pennsylvania temporal limits on coalification in the central appalachians authigenic nh 4 bearing illites in coal fractures from the anthracite region of eastern pennsylvania yield individual k ar dates of 236 253 ma 8 m y and a composite isochron of 253 ma 8 m y rb sr data for the same samples indicate an isochron of 260 ma 44 m y consistent with the more precise k ar data the age of nh 4 bearing illite authigenesis should reflect the time at which coal attained anthracite rank because mineralogical and geochemicai evidence indicates that nh 4 bearing illite formed exclusively during anthracite formation t 200 275 c from organically derived nitrogen and a kaolinite precursor similar late permian k ar dates for both nh 4 rich illite and k illite in anthracite fractures and lack of correlation between percent nh 4 substitution in illite and the k ar date suggest that nh 4 does not influence significantly the closure temperature of illite and thus that nh 4 rich illite can be used for dating the time of authigenesis given the uncertainties in closure temperatures for illite as well as the maximum temperatures for anthracite formation we consider the oldest k ar date of 253 ma 8 m y to be a minimum age for nh 4 illite authigenesis and anthracite formation based on the retention of a detrital age signature in the re examination of syn and post folding secondary chemical remanent magnetizations in rocks from the central appalachians indicates a late early to late permian age 260 250 ma for alleghanian deformation in the vicinity of the anthracite region the age of folding is similar to the 265 255 ma age range for anthracite formation interpreted from illite dates and is consistent with previous studies of vitrinite reflectance fabrics in coal which indicate that anthracite formation occurred prior to and during folding thus age data in conjunction with paleomagnetic and vitrinite reflectance data allow a time period of 25 35 m y for anthracite formation and alleghanian deformation beginning after deposition of the coal in late pennsylvanian or early permian time ca 290 280 ma and concluding by the late permian time ca 260 250 ma significantly longer than previous estimates of less than 15 m y for this thermal tectonic event

gaseous emissions and sublimates from the truman shepherd coal fire floyd county kentucky a re investigation following attempted mitigation of the fire abstract the truman shepherd coal mine fire floyd and knott counties kentucky has been the subject of several field investigations over the last four years during july and november 2011 and january 2012 field investigations we measured gas emissions collected minerals and characterized the nature of the fire new vents opened over the course of the study and have continued to open since january 2012 coincident with the eastward advance of the fire this is the first study of kentucky coal fires where the original vents were able to be studied in addition to new vents on each subsequent trip neoformed minerals associated with the vents are primarily ammonium sulfates and ammonium chlorides with minor zeolites btex emissions especially benzene vary considerably ranging from relatively low to comparable to those from very large fires such as the ankney coal fire in wyoming vent emission data collected displays a general trend of decreasing carbon dioxide and carbon monoxide emissions from july through january the projected annual greenhouse gas and mercury emissions from the fire are 65 69 t of co 2 4 51 t of co 5 73 t of ch 4 and 1 667 kg hg the november 2011 co co 2 ratios are indicative of more complete combustion than at any other time during the study possibly indicative of decreased moisture in the system

stratigraphic control of hot fluids on anthracitization lackawanna synclinorium pennsylvania abstract the lackawanna synclinorium of pennsylvania contains abundant coal that was altered to anthracite rank during the late paleozoic alleghanian orogeny why did the coal in the synclinorium undergo anthracitization two alternatives have been suggested 1 the region was buried deeply during and or after the alleghanian orogeny and thus became hot in response to earth s geothermal gradient and 2 hot fluids migrating from the orogen toward the foreland carried heat into the coal and caused anthracitization if the second hypothesis is correct the region should contain evidence that hot fluids passed through the coal field observations illite crystallinity studies and fluid inclusion analyses indicate that the coal bearing pottsville and llewellyn formations and an underlying detachment fault called the pottchunk fault at or slightly below the base of the pottsville formation acted as a regional aquifer for the migration of hot fluids during the alleghanian orogeny the presence of quartz veins and the hydrothermal minerals tosudite and pyrophyllite in strata above the pottchunk fault and the apparent absence of an illite crystallinity burial gradient in the underlying strata suggest that fluids migrated through large pores in coarse grained sandstones through abundant fractures that developed in response to alleghanian deformation and along the pottchunk fault the quartz veins tosudite and pyrophyllite mineralization do not occur below the pottchunk fault except at one locality suggesting that fluid flow was greater above the fault perhaps because fracturing accompanying deformation increased permeability of the fault s hanging wall fluid inclusions in the pottsville and llewellyn formations indicate fluids achieved a minimum temperature of 270 c at a depth of 3 1 8 5 km heat flow calculations constrained by fluid inclusion data show the heat carried by the migrating fluids through the coal bearing strata was sufficient to elevate the rock temperature to anthracite grade conditions 250 c assuming that the fluid event lasted about 1 year thus deep burial 6 9 km of the coal bearing strata in the lackawanna synclinorium was not required for anthracitization anthracitization was likely the result of stratigraphically controlled hot fluid migration through the coal bearing strata at shallow depths 5 km

no evidence for thermogenic methane release in coal from the karoo ferrar large igneous province abstract the early jurassic toarcian oceanic anoxic event t oae and concurrent negative carbon isotope 13 c excursion have recently been attributed to either the release of methane ch 4 clathrates or thermogenic ch 4 gas associated with the karoo ferrar large igneous province lip into coals and organic rich shales 12 c enriched thermogenic ch 4 production associated with the karoo ferrar would result in residual material being 12 c depleted nearer the intrusions in this study geochemical analyses carbon isotopes volatile matter vm vitrinite reflectance r o are reported for two coal transects associated with dykes intruding the no 4l coal in the highveld coalfield karoo basin south africa vm decreases from over 35 to around 15 in one transect and the second transect shows a less pronounced decrease from 25 to 16 accompanying the decrease in vm content is an increase in r o from background levels of around 0 7 to over 4 adjacent to the dyke used as a palaeo geothermometer r o values indicate background temperatures of 100 c increasing to 300 c close to the contact despite changes in vm and r o there are no significant changes in 13 c certainly not of the magnitude that would be expected associated with large scale thermogenic ch 4 generation these and other gondwanan coals have low vitrinite and liptinite contents components more prone to ch 4 generation in part explaining the modest decreases in vm adjacent to the dykes this combined with the relatively narrow metamorphic aureole surrounding the intrusions and the likelihood that at least some of the volatiles generated by the intrusion were trapped as coalbed ch 4 or condensed as pyrolytic carbon suggests only limited ch 4 release in addition based on original estimates of moisture contents in these coals and the depth at time of intrusion 1 000 2 000 m the dykes would have lost most of their energy heating and evaporating water thus having very little remaining energy to generate thermogenic ch 4

julia radar studies of equatorial spread f this paper presents coherent scatter radar observations of plasma irregularities in the equatorial f region ionosphere made with the julia jicamarca unattended long term studies of the ionosphere and atmosphere radar and discusses model equations and simulations pertinent to their interpretation the data set shows that bottom type and bottomside scattering layers are prevalent throughout solar minimum equinox bottom type layers are undifferentiated and relatively weak layers confined to a narrow range of altitudes falling within regions of the ionosphere driven by the e region dynamo these layers are often precursors to large scale radar plumes as well as to bottomside layers which are broader more structured and more intense layers than the bottom type variety bottomside layers are the source of intermediate scale plasma depletions that can ascend and penetrate through to the topside fluid simulations of the collisional interchange instability suggest that dynamo theory explains why one kind of layer emerges at a given time and altitude

vitrinite reflectance anisotropy as a tectonic fabric element the anisotropy of the coal maceral vitrinite was analyzed in relation to the tectonic setting of a coal from the southern anthracite field in pennsylvania for the coal studied the maximum intermediate reflectance plane essentially paralleled the axial plane of the synclinorium n66 e strike 64 se dip

history of applied coal petrology in the united states iv reflections on the centennial of the introduction of coal petrology to north america abstract reinhardt thiessen introduced a thin section based botanically oriented method of coal petrology to north america in 1920 the nomenclature derived from this system although eventually reconciled with and largely superseded by the european reflected light techniques and nomenclature persisted for decades after thiessen s death in 1938 the research by thiessen and his colleagues at the u s bureau of mines was the foundation of applied coal petrology in the united states with research on the preparation coking and hydrogenation properties of coals thiessen s botanical training enabled him to recognize distinct spores in coals although he did not macerate the samples and he did not provide genus and species names the demonstration that he could use spores to correlate coals through the northern appalachian coal basin provided a foundation for regional stratigraphic palynology homer turner an american geologist and fuel scientist was a pioneer in the petrographic study of anthracite using a method of etching polished blocks of anthracite he developed a parallel approach to reinhardt thiessen s studies of thin sections of bituminous and lower rank coals describing well preserved botanical structures this in turn supported the view that anthracite just had a higher degree of metamorphism than bituminous coals opposed to the older view that anthracite had a different botanical origin in a joint study with the u s bureau of mines turner produced a map of equal volatile matter contours isovol across the pennsylvania anthracite fields he was also a collaborator in a study on the x ray diffraction structure of anthracite presaging better known studies by rosalind franklin and others

the relationship of coal optical fabrics to alleghanian tectonic deformation in the central appalachian fold and thrust belt pennsylvania vitrinite in coal is optically anisotropic in reflected light owing to a preferred orientation of its component molecular structure such reflectance fabrics can under some circumstances provide a record of stress and strain events occurring during coal metamorphism based upon observed differences in the orientation and shape of vitrinite reflectance indicatrices vris differing tectonic histories are suggested for three regions within the bituminous and anthracite coal fields of the northern appalachian coal basin pennsylvania vris of coals from the north central fields on the allegheny plateau have oblate geometries similar to those of most coals worldwide indicative of only mild tectonic deformation maximum reflectance orientations for north central field coals are polymodal and aligned with polymodal alleghanian fold axes low volatile bituminous coals from the broad top field south central pennsylvania exhibit much stronger tectonic reflectance fabrics and bear evidence that low volatile bituminous rank was attained only after folding was completed in this part of the fold and thrust belt vris of coals from the western middle anthracite field reflect a more complex tectonic history and indicate that most coalification here preceded the final phase of alleghanian folding vrls of coals from an underground mine in the western middle anthracite field provide additional details on strain directions and timing of coalification coal rank increases very slightly down section but r min decreases down section opposite to the expected trend these coals probably attained anthracite rank prior to the principal phase of alleghanian folding but at least some coalification continued after folding as suggested by reconstructed coalification pathways on the axial ratio diagram during this final coalification phase the stratigraphically upper beds caught up in rank with the stratigraphically lower beds through elongation of r max parallel to the fold axes and elongation of r min in a subvertical direction vris of the stratigraphically upper beds were transformed to a prolate geometry whereas those of the lower beds retained their original oblate form

co2 storage potential of south african coals and gas entrapment enhancement due to igneous intrusions abstract methane outburst events have occurred in some underground coal mines of south africa such as those in twistdraai mine in the highveld coalfield in the early 1990s occurrences of methane outbursts suggest that high gas content in adsorbed and free phase might be present in some sections of the coal seams coal seams might also be friable in those sections allowing pulverisation during outburst the survey of gas outburst events indicates that the locations of high gas emissions were mainly in the vicinity of the igneous intrusions mainly dolerite intrusions these intrusions are a result of post depositional volcanism into coal seams in some major coalfields of south africa such as the highveld coalfield this study was undertaken firstly to investigate potential locations for the occurrence of coal seam gas in south african coal seams with respect to the igneous intrusions and their enhancement effect on gas release and storage of these coals secondly it was thought that as the metamorphosed coals with high ash content were not economically viable for mining they might be potentially suitable for co 2 disposal measurements on 14 coal samples taken in an underground coal mine at various distances from a dolerite dyke show that the adsorption and porosity properties of metamorphosed coals have been enhanced thus increasing their gas storage capacity diffusivity results show that dolerite intrusions would act as enclosures and gas traps for storage of gas gas diffusivity was greater in coals near the dyke by a factor of two in general it is expected that the co 2 storage and gas flow properties of such coals be enhanced due to the heating effect of intrusions making the coals more appealing for possible future sequestration of co 2 from anthropogenic sources

clay mineral authigenesis in coal and shale from the anthracite region pennsylvania textural chemical and mineralogical analyses of authigenic clays in anthracite rank coal and associated shale from eastern pennsylvania have allowed a better understanding of the parameters controlling diagenesis and perhaps coalification in this region minerals in anthracite occur in distinct assemblages associated with the following microenvironments coal matrix two orthogonal joint sets termed systematic and nonsystematic cleat and a third joint set mineralogical differences among microenvironments allow inferences about clay mineral origins and the parameters that controlled mineral authigenesis kaolinite occurs in the shale and all microenvironments within the coal seam authigenic minerals that replaced preexisting kaolinite during the latest stage ofcoalification anthracitization at t 200 c include nhu rich illite pyrophyllite and the following minerals which are primarily restricted to the systematic cleat set tosudite rl ordered dioctahedral mixed layer chlorite smectite sudoite di trioctahedral chlorite and rectorite rlordered mixedjayer paragonite smectite alteration of smectite to illite may be responsible for formation of authigenic illite and na bearing illite which are present only in the shale and coal matrix and fe al rich chlorite and quartz in the third joint set the chemical components for authigenesis appear to have multiple sources ai and si from preexisting kaolinite and quartz n from local organic matter mg and na for tosudite sudoite and rectorite largely from metasomatic hydrothermal fluids fe and mg for fe al rich chlorite from smectite illitization minerals in the shale the coal matrix and the nonsystematic cleat set are interpreted to represent authigenesis in a low permeability environment closed system alteration however the assemblage sudoite tosudite rectorite in the systematic cleat set is interpreted to be the result ofone or two stages ofhydrothermal alteration open system alteration we suggest hat differences in minerals between the two nearly perpendicular cleat sets are the result of permeability differences which were maintained by an anisotropic lateral stress field created by plate convergence during the alleghanian orogeny hydrothermal alteration may be related to large scale basinal flow induced by alleghanianage uplift such migrating fluids could also have transported heat from depth and thereby significantly increased the rate and rank ofcoalification in this region

reflectance anisotropy of upper carboniferous coals in the appalachian foreland basin pennsylvania u s a abstract patterns of vitrinite reflectance anisotropy in coal are represented by a three dimensional graphical form resembling an ellipsoid termed the vitrinite reflectance indicating surface vri naturally occurring vris from the northern appalachian basin pennsylvania range in shape from biaxial negative to biaxial positive depending on their coalification history and tectonic setting vri shapes are measured by estimating the magnitudes of the three principal reflectances rmax rint and rmin either on oriented blocks or non oriented grain mounts spatial orientations of the principal axes are determined by reflectance measurements on oriented polished cores the various vri shapes are portrayed on axial ratio diagrams i e plots of r max r int on the vertical axis and r int r min on the horizontal axis axial ratio diagrams are also used to depict the progressive change in vri shape with coalification standard deviations of the principal reflectance axes as measured on oriented cores average around 0 09 in magnitude and 5 in orientation measurements are highly reproducible between pairs of oriented cores estimates of the principal reflectance magnitudes as measured on oriented vs non oriented samples agree on average to within 0 04 for rmax 0 08 for rint and 0 20 for rint coal bearing strata in the north central coal fields medium volatile bituminous coal to semianthracite in northern pennsylvania were diagenetically altered in a predominantly burial strain environment and exhibit structural evidence of only mild tectonic deformation vris from this suite of coals are biaxial negative with rmin axes roughly perpendicular to bedding with increasing rank toward the southeast these vris plot along a straight line pathway on the axial ratio diagram emanating from near the origin and extending through the biaxial negative deformation field vris of coals from the western middle anthracite field exhibit a wide range of shapes and orientations which is indicative of a more complex tectonic history in their present day orientation rmin axes are scattered about a great circle distribution the pole to which is precisely coincident with regional fold axes when beds are unfolded to a flat lying orientation they become significantly less scattered indicating that most coalification here preceded the final phase of alleghanian folding rmax axes of sporinite grains are alwayas aligned parallel to bedding which suggests that the strata were still flat lying and not subject to tectonic forces when the coals passed through the 1st and 2nd coalification jumps

anatomy of an intruded coal i effect of contact metamorphism on whole coal geochemistry springfield no 5 pennsylvanian coal illinois basin abstract if time and heating rate are important agents in coal maturation one might expect to see differences in chemical changes in response to maturation depending on the means of increased rank using a suite of samples obtained from an intruded pennsylvanian age coal in southern illinois we present whole coal chemical data comparing these data to extant geochemical data for coals that have undergone normal burial maturation we evaluated the hypothesis that if coal alteration occurs rapidly due to intrusion rather than gradually burial maturation then different relationships are seen in chemical composition proximate and ultimate analyses and vitrinite reflectance the pennsylvanian age asturian westphalian d springfield no 5 coal is mined at the big ridge mine near eldorado southern illinois this high volatile b bituminous coal was intruded by an ultramafic igneous intrusion during the early permian alteration occurs out to 1 2 dike thickness and includes an increase in random vitrinite reflectance rm from levels 0 7 to over 5 3 loss of liptinites and formation of devolatilization vacuoles and fine mosaic texture decreases in volatile matter vm and increases in fixed carbon fc appear to be less than would be expected for the level of reflectance seen within the alteration halo carbonate minerals have a major influence on proximate analyses but even following the removal of carbonates the decrease in vm is still less than would be seen in coals of similar vitrinite reflectance that were altered by normal burial maturation carbonate mineralization also contributes to variability in ultimate analysis values approaching the intrusion particularly for c and o after carbonate removal data for these coals do not appear to follow the normal burial coalification tracks when plotted on a van krevelen diagram and on a seyler chart these differences suggest that a slightly different maturation pathway may have been followed by these coals and by others that were altered rapidly by intrusion

variation in elemental composition of macerals an example of the application of electron microprobe to coal studies abstract elemental composition of macerals in lignite sub bituminous high volatile bituminous medium volatile bituminous and anthracitic rank coals have been investigated using the electron microprobe technique the concentration of c o n s fe si and al have been measured directly and hydrogen was calculated by difference the chemical composition was compared to reflectance values and whole coal chemistry in lignite the sequence ulminite 66 27 c porigelinite 67 32 c micrinite 67 92 c corpocollinite 68 21 c macrinite 70 24 c and fusinite 73 03 c represents a series with increasing carbon content sulphur concentration is the highest in porigelinite 2 95 and the lowest in fusinite 0 21 whereas nitrogen is the highest in corpocollinite 3 12 and the lowest in micrinite and porigelinite in sub bituminous coal the sequence of decreasing carbon content is as follows macrinite 80 01 c sporinite 73 00 c semifusinite 72 76 c and telocollinite 67 49 c sulphur content is the highest in telocollinite 3 29 in high volatile bituminous coal carbon content is highest in fusinite 93 68 and lowest in cutinite 82 82 vitrinite macerals have the highest sulphur content and fusinite has the lowest in medium volatile bituminous coal a sequence of decreasing carbon and increasing oxygen content fusinite 90 02 c semifusinite 89 73 c and vitrinite 88 56 c is detectable but differences in carbon and oxygen content between macerals are small in anthracite no statistical differences in carbon and oxygen content between vitrinite and inertinite macerals exist about 94 c and 1 o for both macerals comparison of reflectance values to carbon and oxygen contents for individual macerals demonstrates that vitrinite and sporinite enter a common coalification path at 88 5 c and a reflectance of 1 25 semifusinite joins the path at about 89 c and a reflectance of 1 8 2 0 more data are needed to determine the relationship between reflectance and elemental composition for other macerals

deep burial of coal bearing strata anthracite region pennsylvania sedimentation or tectonics recent studies of vitrinite reflectance sedimentary compaction and fluid inclusions indicate that coal bearing strata of the pennsylvania anthacite region were once buried at depths ranging from 6 to as much as 9 km vitrinite reflectance anisotropy suggests that anthracite rank was attained by normal geothermal heating largely prior to and during alleghanian folding paleomagnetic ages for the folding and paleobotanical ages of the youngest extant sediments delimit the maximum burial and deformation to a relatively short interval 285 to 270 ma in comparison with typical molasse sequences the implied thicknesses and rates of deposition are excessive suggesting that much of the former overburden was emplaced tectonically or by extremely rapid sedimentation the total implied thickness about 20 km of paleozoic strata in the region is abnormally large for an epicontinental basin an inferred body of mafic rock embedded in the precambrian basement evidenced by the scranton gravity high sgh may have influenced crustal subsidence especially during the allegheny orogeny and produced a large downwarp accounting for the high coal rank the fact that isorank contours paleozoic sediment isopach contours and a large structural sag all lie roughly parallel to the boundaries of the sgh oblique to the principal alleghanian fold trend lends support to this idea

pyrolysis gas chromatography of asphaltenes and kerogens from source rocks and coals a comparative structural study abstract pyrolysis gas chromatography of asphaltenes isolated from source rock and coal extracts and the corresponding kerogens show the same general pyrolysis characteristics while the pyrograms of asphaltenes associated with type i and ii kerogens are dominated by an aliphatic n alkene n alkane homology the pyrolysates of coal asphaltenes show a high abundance of aromatics the asphaltene pyrolysates differ from those of the related kerogens principally in that the relative abundance of isoprenoids and long chain hydrocarbons is higher in the asphaltene pyrograms these differences were minimized with increasing maturity suggesting comparable structures for mature asphaltenes and kerogens and that pyrolysis of asphaltenes should be integrated with other methods which are used in source rock geochemistry

an occurrence of coked bitumen raton formation purgatoire river valley colorado u s a abstract numerous examples of coke produced by igneous intrusion into coal have been reported in the spanish peaks region of south central colorado however in a recent study of an intruded section of the raton formation upper cretaceous paleocene along the purgatoire river near medina plaza co coked bitumen has been observed this material occurs in fingers hexagonally jointed bodies in a shaley xenolith within a lamprophyre sill and in carbonaceous type iii shale directly below the sill the coke fingers are characterized by a remarkable flow mosaic texture high vitrinite coke reflectance average random reflectance between 8 and 9 but with maximum readings around 14 15 high anisotropy abundant devolatilization vacuoles and an absence of inertinite inclusions within the underlying shales the coked bitumen occurs as pore void and fracture linings and fillings geochemically the coke in the fingers has low s1 and s2 values these observations suggest that the coke found in this study was not formed by the direct coking of coal but from a mobile phase bitumen or pitch that was subsequently coked by the intrusion this bitumen was either derived from the abundant coal within the section above the sill or from the organic matter contained within the type iii carbonaceous shales or both unaltered type iii shale sampled at this site has a hi of 350 mg hc g toc suggesting some albeit limited capacity to generate petroleum we suggest that bitumen was generated prior to or during the time of intrusion and was subsequently coked by the high temperatures of the emplaced sill as the bitumen pooled adjacent to the sill rapid heating led to the development of mesophase resulting in a highly anisotropic ribbon mosaic texture on cooling and vaporization of gases that subsequently condensed along pores vacuoles and fractures as pyrolytic carbon and spherulitic pyrolytic carbon bitumen within the underlying silty shales was also coked but to a lesser degree the texture of this coked bitumen looks very much like commercially produced petroleum coke this coked bitumen differs from other reports of coked bitumen in its mode of occurrence coke fingers in a xenolith ribbon mosaic structure and extremely high anisotropy and reflectance

a geologic history of the north central appalachians part 3 the alleghany orogeny the north central appalachians occupy a critical position within the 3000 km long appalachian orogen lying southwest of the boundary between the central and northern appalachians cnab the one billion year long history of tectonic activity in eastern laurentia includes the creation and evolution of the appalachian orogen during the paleozoic and the mesozoic transformation of the orogen into a passive margin during pangea9s disassembly a most important ingredient in the evolution of the orogen was the alleghany orogeny which was driven by the convergence and collision between laurentia laurussia and west gondwana africa the alleghany orogeny in the central and southern appalachians was a decollement tectonism that involved a larger part of eastern laurentia than had the previous three orogenies the fundamental element was a very low angle thrust decollement that originated in mid crustal levels east of the presently exposed appalachians and rose westwardly to progressively higher levels in the upper crust and the supra crustal paleozoic section alleghany deformation was widely developed in the hanging wall block allochthon primarily in the form of thrust faults and fold and thrust structures both of which splayed upward from the basal decollement the youngest manifestations of the alleghany orogeny were northeast trending strike slip faults and dextral shear zones in the piedmont in the north central appalachians the exposed allochthon consists of two parts the sedimentary externides appalachian plateau and valley and ridge provinces and the crystalline externides reading prong blue ridge belt and piedmont province long thrust cored anticlines predominate in the sedimentary externides a widespread layer parallel shortening preceded the folding it is largely coaxial with the folding but extends considerably farther to the northwest toward the craton it is hypothesized that the folding developed in reverse order sequentially from the northwest to the southeast the crystalline externides are dominated by low angle thrust faults and upright folds trending east northeast the first order valley and ridge folds on the northwest side acted as a buttress and diverted the crystalline externides rocks north northwestwardly onto the topographic low area over the anthracite region this thrusting of the crystalline externides caused anthracitization of the coals within the pennsylvanian rocks there metamorphism and magmatism were significant events during the earlier phase of the alleghany orogeny in the southern appalachians whatever magmatism and medium to high grade metamorphism developed in the north central appalachians are in the covered internides to the southeast the alleghany orogeny of the north central appalachians occurred during the early permian erosion of anticlinal crests probably began as the folds grew with accumulation of this locally derived sediment in the intervening synclines a regional alluvial plain coalesced above the partially eroded externides structures as erosion of the pre alleghany highland and the alleghany hinterland mountains continued to the southeast spreading sediment to the northwest this erosion and northwest transport probably persisted with diminishing intensity throughout the remainder of the permian and into the mesozoic and changed only with the beginning of crustal extension during the late triassic

digital ionosonde observations during equatorial spread f in this paper we present and discuss equatorial spread f data taken with a digital ionosonde hf radar located at huancayo peru a modified phenomenology is developed which uses the system s ability to do echo location the onset of irregularities is seen to occur in the east and to move westward while inside this large scale structure the plasma is found to drift eastward a very curious difference has been identified between spread f observations with the ionosonde and with the vhf radar at jicamarca at vhf spread f onset often occurs when the ionosphere is rising whereas in all five examples presented here the digital ionosonde detected onset when the apparent ionosphere motion was downward the result even held on the one night of common data taking the effect could be instrumental but may be related to the considerable orographic differences in the two sites isolated scattering patches are observed and are tentatively identified as detached or fossil plumes at frequencies above the nominal f0f2 the system and other ionosondes may in fact function as a coherent radar during one night data were obtained simultaneously with the hf radar a rocket and the jicamarca vhf radar comparisons of these data are discussed in detail finally additional evidence is presented that acoustic gravity waves play a role in the development of equatorial spread f and in the formation of detached plumes to be self consistent the gravity waves must come from nearby sources such as the tropical rain forest to the east of jicamarca

igneous activity and organic maturation in the midland valley of scotland abstract the general relationship of erich stach s research work to the effects of igneous activity on organic maturation is briefly considered the geological history of the midland valley of scotland is then reviewed as a graben which developed in devonian old red sandstone times and continued to do so as lithospheric tensional stretching was maintained throughout the carboniferous a significant factor in relation to the development of organic maturation was the widespread igneous activity that persisted throughout much of upper palaeozoic times calc alkaline volcanic rocks are a major feature within the molasse type deposits of the old red sandstone after a period of quiescence in later old red sandstone times the continuing tensional stretching initiated or rejuvenated major crustal fractures extensive volcanic sill and dyke activity exercised an important influence on the predominantly shallow water deltaic deposits of the carboniferous alkaline olivine basalts were erupted in the early carboniferous while volcanic activity in the later carboniferous was essentially phreatic two major intrusive episodes occurred the first of alkaline sills in early to mid carboniferous times which were closely related to volcanic plugs and eruptive centres the second in post westphalian times when tholeiitic sills and dykes with no known relationships with any extrusive rocks were injected the effects of this igneous activity on organic maturation can be considered under four headings 1 1 although the general development of maturation of carboniferous organic matter which includes many coal seams and oil shales was controlled to some degree by burial history the regional pattern of igneous activity was also influential thus there is a gradual increase of coalification from east to west in the midland valley which corresponds with an increasing thickness of volcanic pile in the central and westerly parts of the graben suggesting that there may have been a greater regional heat sink in the west during the carboniferous the level of coalification is nowhere particularly high except where affected by intrusions and regional reflectance gradients generally vary between r oil vitrinite 0 2 km to 0 4 km without displaying any consistent pattern 2 2 the post westphalian tholeiitic quartz dolerite midland valley sill which underlies most of the central and eastern parts of the graben has produced extensive reflectance thermal aureoles in the organic matter above and below the intrusion the olivine dolerite and teschenite sills of namurian early westphalian times many of similar thickness to the quartz dolerite intrusions fail to produce significant reflectance thermal aureoles this major difference in organic matter response to the intrusions can only be explained in terms of the initial rank level of the organic matter differences in degree of compaction of the sediments and particularly in the amount of water the sediments contained at the time of intrusion 3 3 maturation of organic matter closely associated with extensive surtseyan type volcanic activity in the eastern part of the graben displays no relationship to the regionally developed coalification in associated sediments although some vitrinite clasts in the pyroclastic deposits have had their reflectances raised to meta anthracitic rank reflectance levels of clasts in tuffs and agglomerates are generally not much raised above the regional reflectance level suggesting incorporation of organic matter in ash streams in which water was an important cooling and protective component 4 4 the close relationship of organic matter of all kinds with volcanic and intrusive igneous rocks has led to a marked increase of parent polycyclic aromatic hydrocarbons pah in the aromatic fractions of organic extracts the source of these hydrocarbons is the combustion and or pyrolysis of organic matter caused by the high temperatures of the igneous materials whether volcanic or intrusive these pah may be directly generated or absorbed from the surrounding environment

variations in elemental and mineralogical compositions of late oligocene early and middle miocene coal seams in the kale tavas molasse sub basin sw turkey abstract the kale tavas sub basin which is the south western part of the lycian molasse basin sw turkey hosts several coal seams of late oligocene early and middle miocene age within respectively the mortuma yenidere and sekkoy formations this study aims to determine coal rank mineralogical and geochemical features of the coal seams and to ascertain factors controlling the mineralogical distribution and elemental enrichment the distinct differences among the studied coal seams refer to mean random huminite vitrinite reflectance rr the highest rr values 0 63 0 69 are measured on the late oligocene tavas coal whereas the lowest rr values 0 26 0 27 were recorded in the middle miocene narli coal similar mineralogical assemblages were found in all the studied coal seams however aluminosilicate minerals are dominant to abundant phases in the coal from the mortuma and yenidere formations while carbonate minerals are the dominant phases in the coal from the sekkoy formation accordingly aluminosilicate related elements e g al k ti and li display relatively higher concentrations in the studied coal seams from the mortuma and yenidere formations whereas relatively high ca concentrations and depletion of aluminosilicate affiliated elements were recorded in the coal of the sekkoy formation furthermore ni mo and u are relatively enriched in all the studied seams while relative b enrichment is identified in the coal seams of the mortuma and yenidere formations and these seem to be related to possible marine influence of the palaeomires during late oligocene and early miocene and or the occurrence of specific b bearing aluminosilicate minerals also u and mo enrichments in the narli coal may be related with the development of anoxic conditions within the palaeomires during the middle miocene other indicators for anoxic conditions are framboidal pyrite grains and accessory ni bearing iron sulphides in all the studied samples although coal bearing formations in the kale tavas sub basin deposited under different sedimentary environment as the source areas for sediment supply of the coal seams remained the same during the late oligocene to early miocene the mineralogical composition and elemental enrichment of the coal were mainly controlled by clastic inputs and redox conditions within the palaeomires to a lesser extent a possible marine influence might have contributed to elemental enrichment

geochemistry of asphaltenes abstract asphaltenes derived from both oil and source rocks have been studied by pyrolysis gas chromatography the pyrograms obtained at 450 and 550 c show that asphaltene structure is very close to the structure of the kerogen of the same sample they can be interpreted as kerogen moieties resulting from its early evolution therefore they can be used as substitutes of kerogen in genetic studies consequently asphaltenes pyrolysis appear to be a tool in correlation studies for oil oil correlation it can supplement and even replace in the case of degraded oils the information given by hydrocarbon distributions for oil source rock correlations the match between pyrograms of asphaltenes from both oil and source rocks offers more direct possibilities than usual techniques

a study of the effect of igneous intrusions on the structure of an australian high voltage bituminous coal abstract samples of heat affected coal taken near two igneous intrusions dykes in the victoria tunnel seam of the newcastle coalfield have been investigated by chemical analysis petrography fourier transform infrared spectroscopy and solid state 13 c nmr spectroscopy visual inspection of the seam near the intrusion showed four distinct zones these have been called in order of increasing distance from the dyke the massive cinder the banded cinder heat affected coal and apparently unaffected coal the samples show an increase in structural change as the distance from the dyke decreases with the samples taken from the massive cinder nearest the dyke being classified as semicokes ftir and 13 c nmr results together with the results of dipolar dephasing nmr experiments suggest that the predominant structural change in the heat affected zone is replacement of aromatic ethers and or phenols with hydrogen leading to an increase in proton aromaticity closer to the intrusion bond rupture leads to a marked loss of aliphatic groups while in the most affected region adjacent to the dyke aromatic crosslinking has also occurred to form coke like material

effects of rapid thermal alteration on coal geochemical and petrographic signatures in the springfield no 5 coal illinois basin abstract igneous intrusion into a coal bed can change the geochemical and petrographic properties of the coal including vitrinite reflectance maceral petrographic composition optical texture mineralogy stable isotope composition trace element composition and bulk geochemistry the intent of this study was to evaluate petrographic and geochemical changes in an intruded coal and compare them to trends seen in coals altered by normal burial maturation thereby evaluating whether or not the intruded coals followed a different maturation pathway the current study reports petrographic bulk geochemical proximate ultimate leco total organic carbon toc and rock eval pyrolysis data for a suite of samples from the springfield no 5 coal pennsylvanian desmoinesian in the southern part of the illinois basin where the coal had been intruded by a permian age peridotite dike petrographic analysis shows an increase in vitrinite reflectance rm from background levels of 0 55 0 63 up to 4 80 a loss in ability to differentiate liptinite macerals formation of isotropic coke and at the dike coal contact development of fine grained mosaic anisotropic coke texture volatile matter vm content decreases and fixed carbon fc content ash and mineral matter parr formula increase approaching the intrusion contact carbon increases whereas nitrogen hydrogen and oxygen decrease approaching the intrusion the presence of carbonate minerals confirmed by x ray diffraction and petrographic analysis has a significant impact on proximate and ultimate data however even after removal of carbonates trends for vm vs rm c vs rm and h vs c do not follow typical trends associated with normal burial coalification approaching the contact leco toc rock eval free oil content s1 remaining hydrocarbon potential s2 co2 from pyrolysis of the organic matter s3 and hydrogen hi and oxygen oi indices decrease whereas thermal maturity tmax c increases s2 vs rm and tmax vs rm diverge from the pathways seen in previous studies of coals that have undergone normal burial maturation geochemical data from this study suggest that the intruded springfield no 5 coal may have followed a maturation track that differed from that seen under normal burial maturation perhaps due to the geologically rapid high heating event associated with the emplacement of the intrusion it is also suggested here that the natural coke textures produced by this rapid geological heating may differ from those observed for metallurgical cokes produced under standard industrial coking conditions typically in an industrial coke oven a coal of this initial rank ro 0 6 would produce an isotropic coke rather than the fine grained circular anisotropic coke seen here however as variations in heating rate duration of heating maximum temperatures attained hydrothermal conditions and pressure are mostly unknown for the intrusive event it is not unreasonable to suggest that differences in these variables contributed to the higher anisotropy of the coke alternatively the development of this texture may reflect pre heating of the coal during the intrusion event

on the generation and growth of equatorial backscatter plumes 1 wave structure in the bottomside f layer we examine the initial conditions that lead to backscatter plume development in the equatorial f region ionosphere by analyzing altair radar data we obtained the following principal results 1 prior to plume development an altitude modulation of electron density contours exists in the bottomside f layer these quasi periodic variations were mapped spatially over a 1200 km east west distance by using incoherent scatter measurements and found to consist of three cycles with an average spatial wavelength of 400 km 2 the wave structure observed in the bottomside electron density contours grew in amplitude at a rate consistent with that predicted by the generalized gradient drift instability 3 bottomside backscatter developed on the west walls of all three altitude modulated regions followed by plume development from near the crests of these regions

aberrations in the coalification patterns of the offshore coalfields of northumberland and durham united kingdom abstract the offshore extensions of the northumberland and durham westphalian coalfields are formed of continuous and linked sequences of sediments which lie in contrasting structural regimes respectively basin and block the coalfields have suffered different geothermal histories offshore northumberland basin sediments endured low heating rates and low maximum temperatures to give seams which even at the base of the succession hardly reached vitrinite reflectances of roil 0 60 apart from raised values due to igneous activity the offshore durham block succession was exposed to higher temperatures and heating rates due to the proximity of the lower devonian weardale granite underlying the block which was re activated during carboniferous times these geothermal conditions not only led to higher levels of reflectance and steeper maturation gradients offshore in the block succession than offshore in coals of the basin but also produced contrasting relationships between correlations of vitrinite oil reflectance and volatile matter yield of coals for the two structural zones and probably also for other property relationships as well reflectance profiles have been modified due to three circumstances first considerable variation locally in the raising of reflectance levels caused by igneous activity second lowering of vitrinite reflectance values due to arenaceous sediments being deposited immediately on top of vitrinite precursors within the coal forming organic matter and third possible interference from liptinite rich accumulations within coal seams or near to them in the succession which exuded aliphatic materials relatively early in coalification which were then absorbed by vitrinites or more likely deposition of the vitrinite precursors in a marine near marine and calcium rich environment so reducing reflectance values on coalification similar contrasting property relationships to those described here may have been produced by lower devonian granitoid bodies which have been identified on the north sea high if they also were re activated during the carboniferous

mechanisms of coal metamorphism case studies from paleozoic coalfields controls on coal metamorphism can be complex in this paper we examine four paleozoic coalfields the western kentucky portion of the illinois basin the pennsylvania anthracite fields the south wales coalfield and the bowen basin an increase in temperature with depth of burial is certainly a factor in coal metamorphism in many coalfields however including the coalfields reviewed here it has become apparent that such a simple mechanism does not explain the coal rank patterns observed the flow of hydrothermal fluids through the coals has been proposed as a cause of coal metamorphism evidence includes inverted rank gradients elevated cfl as an indicator of brine fluids isotopic evidence for hydrothermal fluids and vein and cleat mineral assemblages in any case multiple hypotheses must often be evaluated in the examination of any coalfield since the simple paradigm of coal rank increases with a simple increase in temperature with increasing depth does not fit the evidence observed in many cases

mineralogical and geochemical responses of coal to igneous intrusion in the pansan coal mine of the huainan coalfield anhui china the huainan coalfield where magma is commonly intruded into the coal measures in the northern section e g the zhuji dingji pansan and panbei mines is the largest energy base in eastern china to investigate the mineralogical and geochemical responses of coal to igneous intrusion minerals major and trace elements in sandstone thermally altered coal igneous rock sandy mudstone and unaltered coal samples were collected from a representative profile of the no 1 coal of the pansan coal mine the samples were analyzed using an optical microscope powder x ray diffraction scanning electron microscopy in conjunction with x ray energy dispersive spectroscopy x ray fluorescence inductively coupled plasma atomic emission spectrometry and mass spectrometry the results indicated that the thick sill transformed from mafic rocks at the bottom via intermediate rocks in the middle to felsic rocks at the top of the profile the moisture total sulfur and carbon contents of the coal increased whereas volatile matter hydrogen and nitrogen decreased during contact metamorphism caused by igneous intrusion epigenetic minerals i e dolomite quartz and pyrite occurred in the thermally altered coals three stages of hydrothermal fluids i e ca mg and fe rich si rich and fe and or h2s rich solutions were identified iron ca s si mg zn cd and pb were transported into the thermally altered coal by hydrothermal fluids the concentrations of co and ni in the thermally altered coal increased in relation to the increase of ash yields that were caused by contact metamorphism whereas the b in the coal was volatilized manganese is directly related to the intrusive magma phosphorus ge and sr might be introduced into the coal by groundwater however k na ga and ba were leached out titanium sc cr v cu zr nb and rare earth elements and yttrium rey in the coals originated from terrigenous input and were not influenced by igneous intrusion

use of clay mineral alteration patterns to define syntectonic permeability of joints cleat in pennsylvania anthracite coal abstract joints cleat in pennsylvania anthracite contain two distinct clay mineral assemblages both of which formed by alteration of preexisting kaolinite at peak metamorphic conditions during the alleghanian orogeny the first assemblage nh4 illite or pyrophyllite quartz formed by reaction of kaolinite with methane rich fluids derived from within the coal the second assemblage sudoite tosudite rectorite berthierine formed by the reaction of kaolinite with ferromagnesian bearing hydrothermal fluids which must have come from outside the coal in an earlier paper we suggested that the first assemblage indicated clay diagenesis in low permeability environments and that the second assemblage indicated clay diagenesis in high permeability environments if this premise is correct then the distribution of clay mineral alteration assemblages serves to define syntectonic permeability variations in coal cleat the first assemblage dominates in the coal matrix itself in isolated cleat in cleat that parallel the regional trend of alleghanian folds and in the mirror portions of cleat oriented perpendicular to the fold trends suggesting that these regions are low permeability environments the second assemblage dominates in the hackle fringe of interconnected cleat that trend perpendicular to the strike of the appalachian orogen suggesting that these regions are high permeability environments our results emphasize that syntectonic cleat permeability is a function of cleat orientation macroscopic cleat interconnectivity and orientation as well as microscopic cleat surface morphology

influence of a basic intrusion on the vitrinite reflectance and chemistry of the springfield no 5 coal harrisburg illinois abstract the springfield no 5 coal a pennsylvanian age high volatile b bituminous rank coal in the carbondale formation is mined in the southeastern section of the illinois basin intruded into this coal is a 10 1 m wide basic dike that is near vertical through the extent of the mined coal bed and strikes n 22 w the intrusion and the effects it had on the coal were studied petrographically and geochemically using a published heat flow model by carslaw and jaeger 1959 carslaw h s jaeger j c 1959 conduction of heats in solids oxford university press in conjunction with thin section microscope analysis a contact temperature of 600 c was determined vitrinite reflectance was measured for a suite of coal samples collected distal to the intrusion vitrinite reflectance values rose uniformly from the ambient reflectance values of 0 69 at just greater than one dike thickness away to 5 at the dike coal contact the increase in reflectance values for samples within 1 2 times dike thickness is concordant with data published by bostick and pawlewicz 1984 bostick n h pawlewicz m j 1984 paleotemperatures based on vitrinite reflectance of shales and limestones in igneous dike aureoles in the upper cretaceous pierre shale walsenburg colorado in woodward j g meissner f f clayton j l eds hydrocarbon source rocks of the greater rocky mountain region rocky mountain association of geologists pp 387 392 on the effects of mafic intrusions into cretaceous age shales in walsenburg colorado comparison of colorado data with data from these sites indicates that despite differences in intrusion temperature timing or coal rank at time of the intrusion ambient mean vitrinite reflectance values remain unchanged at just greater than one dike width from an intrusion

the prereversal enhancement of the zonal electric field in the equatorial ionosphere the electric fields in the ionospheric e and f regions near the magnetic equator often show a strong eastward enhancement shortly after sunset and before the eastward normally daytime field reverses to westward several theoretical models of the low latitude fields suggest that this enhancement is caused mainly or entirely by f region winds the f region dynamo but some authors have suggested that it could be produced solely by e region tidal winds we give here additional calculations and arguments in support of the f region source the enhancement of the eastward field for an eastward f region wind turns out to be a simple direct consequence of the fact that after sunset the ionospheric conductivity decreases far more rapidly in the e region than in the f region

effects of igneous intrusions on coalbed methane potential gunnedah basin australia abstract the gunnedah basin nsw australia contains more than 500 gt of coal and has been the subject of recent coalbed methane exploration large areas of the basin contain igneous intrusions and large areas of coal have been heat affected as a consequence a detailed study has been undertaken of coal seams intersected in a cored coalbed methane exploration drillhole in which two sill form igneous intrusions are present comparisons are made between coals that are unaltered and coals that have been heat affected using petrographic and chemical data coal seam gas desorption data and gas chemical analysis data results demonstrate that the two igneous intrusions have had a very positive effect on coalbed methane development the gas content in a number of heat affected coal seams within thermal aureoles above and below the sills is substantially higher than in adjacent unaffected coal seams in addition the intrusions have had little effect on gas quality the coals in the heat affected zone were found to contain gas with approximately 95 methane the coals in the thermal aureoles were found under the microscope to contain characteristic micropores and slits which collectively may serve to enhance gas adsorption capacity permeability and gas desorption gas contents below each of the sills is substantially higher than above the sill confirming earlier results that the sills appear to have acted as a reservoir seal during and for some time after intrusion the background coal rank in acm yannergee ddh 1 is in the high volatile bituminous range the igneous intrusions have resulted in an increase in rank such that large areas of coal have moved into the optimal thermogenic gas generation window this rank increase has affected a major part of the coal bearing sequence

the coalification of south african coal abstract it has been generally accepted that the variation in rank of south african coal is essentially due to the metamorphic effect of dolerite dykes and sills however no satisfactory explanation could be given for the fact that true anthracite has not been formed adjacent to dykes and transgressive sills in those south african coal fields where the rank of the coal is normally low in these areas the coal close to the intrusives is often referred to as burnt a detailed examination of the contact metamorphism of south african coal by dolerite intrusives shows that a dyke or sill affects the coal to variable distances generally from 0 6 to 2 times the thickness of the intrusive and that this distance is independent of the rank of the coal outside the contact aureole this is explained by an initial episode of contact metamorphism while the coal was still in the lignite stage of coalification followed by burial metamorphism during which the paleogeothermal gradient increased in an easterly direction this regional increase in paleogeothermal gradient is probably related to the large scale magmatic activity that culminated in the extrusion of the drakensberg basalts and the break up of gondwanaland

global distribution of density irregularities in the equatorial ionosphere we analyzed measurements of ion number density made by the retarding potential analyzer aboard the atmosphere explorer e ae e satellite which was in an approximately circular orbit at an altitude near 300 km in 1977 and later at an altitude near 400 km large scale 60 km density measurements in the high altitude regions show large depletions of bubble like structures which are confined to narrow local time longitude and magnetic latitude ranges while those in the low altitude regions show relatively small depletions which are broadly distributed in space for this reason we considered the altitude regions below 300 km and above 350 km and investigated the global distribution of irregularities using the rms deviation n n over a path length of 18 km as an indicator of overall irregularity intensity seasonal variations of irregularity occurrence probability are significant in the pacific regions while the occurrence probability is always high in the atlantic african regions and is always low in the indian regions we find that the high occurrence probability in the pacific regions is associated with isolated bubble structures while that near 0 longitude is produced by large depletions with bubble structures which are superimposed on a large scale wave like background considerations of longitude variations due to seeding mechanisms and due to f region winds and drifts are necessary to adequately explain the observations at low and high altitudes seeding effects are most obvious near 0 longitude while the most easily observed effect of the f region is the suppression of irregularity growth by interhemispheric neutral winds

mapping a bubble at dip equator and anomaly with oblique ionospheric soundings of range spread f multiple ionospheric sounders are employed in the first attempt to detect and map remotely an equatorial bubble near the dip equator and simultaneously near the appleton anomaly crest the sounders also provide latitudinal profiles of electron density through 30 degrees dip latitude diplat conditions are solar maximum and low kp using oblique range spread f rsf echoes from the bubble boundaries four sounders located near the dip equator detect a single isolated bubble at ranges as great as a 1020 km and track it for 2 25 hours at 5 min intervals as it drifts eastward through 15 degrees geomagnetic longitude mlong maximum velocity is 185 m s and width is 375 km near the northern anomaly crest a sounder at 20 3 degrees diplat observes the western boundary for a duration of 1 hour concurrently with and magnetically conjugate to the equatorial observations the boundary here has nearly the same drift velocity and mlong as at the equator implying that the boundary location and velocity are nearly independent of altitude above the dip equator subsequently in the south a sounder at 19 9 degrees diplat observes the bubble to have a velocity approximately half that seen by other stations and a mlong that is at least 3 degrees more west of the others this difference may be related to the north south asymmetry of the anomaly crest which is at the location of the northern sounder but equatorward of the southern sounder although the two are at the same diplat the onset of the bubble is recorded in the first appearance of rsf at 1915 local mean time 20 min later the bubble boundary appears and begins accelerating eastward the movement occurring within about 5 min of electric field reversal as inferred from f layer vertical motion 30 refs 8 figs less

stable carbon isotope compositions of crude oils application to source depositional environments and petroleum alteration the carbon isotopic composition of the c15 saturate and aromatic hydrocarbon fractions and the gas chromatographs of the c15 saturate fraction of 339 oils were geochemically and statistically evaluated results of this study show that the average isotopic compositions of the c15 aromatic hydrocarbon fractions of oils sourced from terrigenous or marine organic matter are identical the average isotopic composition of the c15 saturate fraction of oils derived from terrigenous organic sources is slightly more negative 0 9 pmil than the average for marine oils but this difference is insufficient to be used as a reliable source indicator reports in the literature stating that marine oils are isotopically more positive than te rigenous oils and that the difference can be utilized to distinguish between the two are therefore not supported by this study the isotopic differences between oils sourced from terrigenous and marine organic matter do not manifest themselves in the range of absolute values of one oil fraction but rather in the isotopic relationship between the saturate and aromatic hydrocarbon fractions the isotopic relationship is the following oils of terrigenous organic source dgr13caro 1 12 dgr13csat 5 45 oils of marine organic source dgr13caro 1 10 dgr13csat 3 75 the difference between the two equations was evaluated statistically and a statistical parameter cv the canonical variable cv 2 53 dgr13csat 2 22 dgr13caro 11 65 was used to distinguish between marine and terrigenous oils cv values larger than 0 47 indicate predominantly a terrigenous organic source for the oil whereas cv values smaller than 0 47 indicate mostly a marine organic source thermal maturity differences in oils and isotopic variations in the source beds can cause as much as 2 pmil variations in the isotopic composition of one family of oils finally stable carbon isotopes can in some situations help correlate biodegraded oils to their nondegraded counterparts

a comparative study of the stable carbon isotopic composition of crude oil alkanes and associated crude oil asphaltene pyrolysate alkanes abstract normal alkanes and isoprenoid alkanes in crude oils and micro sealed vessel pyrolysates of related asphaltenes sourced from different source rock types have been analysed by gas chromatography isotope ratio mass spectrometry gc irms seven sample sets each consisting of the oil and the related asphaltene from marine non clastic sources marine clastic source a lacustrine clastic source and two from sources from land plant dominated deltaic facies source rocks angiosperm and gymnosperm dominated plant inputs respectively were studied the utility and precision of the gc irms technique are assessed by analysing a a standard n alkane mixture of known isotopic values and a blend of this standard mixture with b a biodegraded oil and c a branched cyclic saturated hydrocarbon fraction the precision of the technique is better than ca 0 25 in four sample sets the individual n alkanes of the asphaltene pyrolysates are enriched in 13c up to 4 compared to the n alkanes in the corresponding oils and follow broadly the same trend with increasing carbon number in the remaining three sample sets marine clastic lacustrine and deltaic gymnosperm derived samples the opposite trend is observed i e here the n alkanes from the asphaltene pyrolysate are isotopically lighter thus perhaps indicating different sources for the n alkanes in the oil and n alkyl moieties in the asphaltenes

hydrothermal alteration in anthracite from eastern pennsylvania implications for mechanisms of anthracite formation orthogonal joint sets cleat in anthracite rank coal beds from eastern pennsylvania contain two mineralogically and chemically different authigenic clay mineral assemblages in localities from all four anthracite fields the systematic cleat contains significant quantities 20 to 95 wt of authigenic rectorite sudoite or tosudite which are clay minerals primarily associated with hydrothermal veins and ore deposits the strike of systematic cleat in this region roughly parallels the inferred direction of lateral compressive stress during the alleghany orogeny the opposing nonsystematic cleat contains mostly authigenic nh 4 illite a clay that also occurs in the coal matrix all of these authigenic clay minerals formed during anthracitization t 200 c by replacement of kaolinite and quartz both of which formed during an earlier stage of coalification and are present in the joints and matrix of nearly all coal samples these distinct mineralogical structural relations are observed throughout the anthracite region and suggest that 1 mineralogical variations in the coal joints are related primarily to permeability variations that were controlled by the orientation of alleghanian stress fields 2 hydrothermal fluids passed through the systematic cleat during anthracitization and 3 hydrothermal alteration influenced diagenesis in this region hydrothermal alteration may be related to basin wide fluid migrations that were driven by alleghanian age uplift basinal fluid flow concentrated along permeable joints and detachment zones could have efficiently transported heat from depth and thereby increased the rate of coalification and decreased the postulated minimum depths at which anthracitization occurred perhaps 5km vs 6 10 km

the distribution of layer parallel shortening fabrics in the appalachian foreland of new york and pennsylvania evidence for two non coaxial phases of the alleghanian orogeny

geochemical and petrographic alteration of rapidly heated coals from the herrin no 6 coal seam illinois basin abstract coals altered by rapid heating events i e those intruded by dikes and sills are thought to follow a different geochemical maturation pathway than coals altered through diagenesis if an igneous intrusion alters the petrographic and geochemical properties of a coal the effect should also be observable in the coal s molecular structure in this study we evaluate whether coals altered by rapid heating follow distinct maturation trends from coals that were altered by slower heating burial maturation petrographic geochemical and micro ftir analyses were performed on a series of pennsylvanian illinois basin coal samples collected at various distances from a permian igneous dike standard coal characterization techniques including vitrinite reflectance and proximate and ultimate analyses provide valuable insights on the maturation pathways experienced by rapidly heated coals these techniques were coupled with reflectance micro ftir to provide a better understanding of the molecular changes that occur in the coal structure during relatively short lived intensive heating events with decreasing distance to the intrusion coals have higher mean random vitrinite reflectance values rr within the dike alteration zone coking textures similar to those observed in industrial cokes are observed within 2 m of the intrusion geochemical data for hcl treated coals indicate an overall loss of h o and n and an increase in c approaching the dike intruded coals have higher volatile matter vm yields at high rank than coals of similar rank that result from normal burial maturation when plotted on a van krevelen diagram or seyler chart intruded coals follow different coalification trends than coals matured through normal burial diagenesis reflectance micro ftir analysis of collotelinite shows increased aromaticity with rank both the ratio of the aromatic ch stretching band at 3100 3000 cm 1 versus the aliphatic chx stretching bands between 3000 and 2800 cm 1 ar1 and the ratio of the aromatic out of plane deformation bands between 900 700 cm 1 versus the aliphatic chx band ar2 increase with increasing rr within the 3000 2800 cm 1 region there is an increase in the area under the asymmetric ch3 peak at 2960 cm 1 relative to the asymmetric ch2 peak at 2920 cm 1 with increased rank within the 900 700 cm 1 region the overall intensity of the 750 cm 1 peak aromatic rings with four adjacent h atoms relative to the 870 cm 1 peak aromatic rings with one isolated h atom increases up to 2 5 rr likely reflecting a lower degree of substitution dos of alkyl groups on aromatic ring sites the prevalence of the 750 cm 1 peak at high rank may represent a lower degree of condensation of aromatic rings in the structure of intruded coals compared to normally matured coals

complex trichomes associated with foliar odontopteris schlotheimii brongniart manebach type locality germany implication for taxonomy abstract reported for the first time is a physical association of complex structured trichomes with foliar odontopteris schlotheimii brongniart 1831 from the type manebach formation germany this is based on examining rock matrices dissolved by hydrofluoric acid of bipinnate and pinnate material these trichomes and their inferred dense distribution most significantly are directly comparable with those of specimens of odontopteris cantabrica wagner 1969 from the canadian sydney coalfield used as index fossil to establish the cantabrian substage this result is one strong argument that invites comparison with o schlotheimii in addition to the acknowledged common pinnule morphologies of o cantabrica and o schlotheimii additionally trichomes are not observed in samples of the rock matrix of a fragmentary axis associated with lesquereux specimen of o schlotheimii southern anthracite field eastern pennsylvania usa results of the trichomic comparison and taxonomic implication thereof will be discussed in a future paper

an equatorial bubble its evolution observed in relation to bottomside spread f and to the appleton anomaly this is a case study that undertakes the first comprehensive description of the concurrent evolutions of an isolated equatorial bubble bottomside spread f bssf and the enhanced appleton anomaly a principal focus is the dynamics of the intersection of the bubble with the anomaly crest which is the source of maximum scintillation on transionospheric rf propagation conditions are equinox at solar maximum measurements were by an array of eight ionospheric sounders in the western hemisphere with a collective field of view extending along the dip equator for about 1600 km and to 40 north dip latitude that resolved rapid changes in the phenomena yet encompassed their extent and duration viewed locally the bubble was triggered by an upwelling of the bottomside f layer during e b upward drift that accelerated upward for 15 20 min before the onset of irregularities seen as range spread f rsf viewed macroscopically this onset was part of continuous front of rsf onset that coincided with e b reversal and moved westward at the velocity of the terminator so as to remain at 1920 lt to the east of the bubble as bssf within the bubble during the upwelling of the bottomside crest at the west wall of the bubble at the onset of its eastward drift and west of the bubble as bssf the bubble drifted eastward at 185 m s and rose upward at 190 m s intersecting the maximum of the anomaly crest at 2100 lt 95 min after bubble onset during this entire period the bubble was in continuous contact with the anomaly profile which was simultaneously increasing but as a function of lt thus the intersection was a function of the upward and eastward velocities of the bubble and the westward motion of the anomaly at the velocity of the terminator the time and place of the intersection is thus dependent on the entire sequence of events and on the differing dependences on ut and lt and since each can vary the time and place of maximum scintillation is highly variable in light of this variability observations at least as comprehensive as those reported here appear to be necessary to describe the region adequately and therefore to study it further

notes on the mechanisms of coal metamorphism in the pennsylvania anthracite fields abstract charred devolatilized megasporinite and featureless vitrinite with devolatilization pores filled with pyrolytic carbon suggest that eastern pennsylvania anthracites may have been altered by to localized episodes of metamorphism from superheated steam co2 co hydrocarbons in addition to the pervasive regional metamorphism based on the extant vitrinite textures the lack of mesophase anisotropic textures and on comparisons to laboratory studies of the thermoplasticity of bituminous coals the rank at the time of metamorphism would have been high volatile c or lowermost high volatile b bituminous the temperature of alteration would have been in the 350 400 c range corresponding to the critical point of steam 374 15 c and 22 1 mpa about 1 km depth it is speculated that while increased pressure would have prolonged the duration of fluid properties fluidity is still a transient property and the vitrinite would have returned to a solid state after a few hours the heat would have persisted dissipating over the course of days to months to years depending upon the depth and ambient pre heating geothermal gradient but contributing to the coal metamorphism long after the vitroplast solidified

incoherent scatter radar ionosonde and satellite measurements of equatorial f region vertical plasma drifts in the evening sector studies of equatorial f region evening vertical plasma drifts using different measurement techniques have produced conflicting results we examine the relationship of incoherent scatter radar and ionosonde drift observations over the peruvian equatorial region and ae e satellite drifts for different geophysical conditions our data show that there is large day to day variability on the ratios of radar and ionosonde drifts but on the average the measurements from these two techniques are in fair agreement during low and moderate solar flux conditions for high solar activity however the jicamarca evening drifts during equinox and december solstice are significantly larger than the ionosonde drifts these results can be explained by the different height ranges of the radar and ionosonde measurements and the increase of the upward drift velocity with height below the f region peak this altitudinal variation is related to the longitudinal gradient of the zonal plasma drifts as a result of the curl free electric field condition our results also indicate that during equinox the increase of the vertical prereversal velocity enhancement with solar activity is largely longitude independent

variations in geochemical character of asphaltenes from a source rock in contact with an oil reservoir abstract asphaltenes are suspected to be essentially small solubilized less condensed kerogen moities these materials should then be excellent for use in evaluation of source environments and as source rock oil correlation parameters this study compares chemical and isotopic compositions of asphaltenes extracted from a 100 m continuous core through the kimmeridge shale of the north sea with associated resins nos as well as with both resins and asphaltenes from the oil of the adjacent sandstone reservoir which is in contact with the shale through gel permeation chromatography two distinct classifications of molecular weight mw distributions for the asphaltenes of the source rock extracts are observed 1 a high mw range 5000 30000 daltons which is associated with enriched carbon isotopic signatures 25 to 26 and 2 a lower mw range 1500 5000 daltons which correlates with more common samples having depleted isotopic compositions 28 to 30 in similar fashion the high mw asphaltenes show increased concentrations of longer chain length alkyl groups nc22 and greater which are released through pyrolysis gas chromatography resins associated with the high mw asphaltenes have a greater high mw content than resins from the more common kerogens coincidences of high carbonate are also noted in most isotopically anomolous samples these data indicate a changing depositional environment probably associated with an increasing bacterial component and recycling an increase in mw of asphaltenes in the reservoir oil was observed and suggests further condensation of these structures may occur in the reservoir following migration or increased level of maturity carbon isotopic compositions of specific mw fractions of resins and asphaltenese support the hypothesis that high mw asphaltenes and resins are precursors in low mw asphaltene and resin generation