the petřkovice member ostrava formation mississippian of the upper silesian basin czech republic and poland abstract the pet kovice member carboniferous mississippian early namurian is in many ways the most interesting lithostratigraphic unit of the paralic part of the carboniferous coal bearing upper silesian basin described as the ostrava formation in the czech part or as the paralic series in the polish part pet kovice member represents a transition between the non coal bearing carboniferous flysch sedimentation of the moravian silesian basin and the coal bearing sedimentation of the upper silesian basin the paper includes maps of the basic sedimentological parameters of this unit thickness sand content and coal bearing capacity the thickness of the pet kovice member ranges from approximately 50 m in the east of the basin to around 770 m in the west and has a clear polarity in the nnw sse direction sand content ranges from 23 in the west of the basin to more than 90 in the east its polarity is approximately the same as its thickness the greatest coal bearing capacity expressed as total thickness of the coal layers with a thickness greater than 10 cm is known from the czech part of the basin where it exceeds 25 m in places in the majority of the polish part of the basin the pet kovice member s total coal content is less than 5 m at times up to 7 m however in this part of the basin their level of recognition is very low on the basis of the above parameters 3 assumed zones of differing mobility in the basin s bedrock are defined in the pet kovice member s area

thermotectonic evolution of the ukrainian donbas foldbelt evidence from zircon and apatite fission track data abstract the donbas foldbelt forms part of a large devonian rift cross cutting the southern part of the eastern european craton it comprises a 20 km thick devonian and carboniferous sedimentary succession maximum burial occurred during early permian time and was followed by a major exhumation phase in this study we use zircon and apatite fission track dating to reconstruct the post depositional thermal evolution of the inverted basin modelling of the fission track data combined with modelling of vitrinite reflectance data reveals that large parts of the basin were affected by a permo triassic 250 ma heat flow event which was presumably related to permo triassic andesitic magmatism this permo triassic thermal event was predicted by previous modelling of vitrinite reflectance data but only the fission track data indicates its wide areal distribution probably large parts of the southern margin of the eastern european craton were affected by this event whereas rocks west of the city of donetsk krasnoarmeisk monocline experienced permo triassic temperatures in the range of 90 105 c rocks northwest of donetsk were heated to up to more than 240 c jurassic temperatures northeast of donetsk were in the order of 90 100 c these relatively high temperatures imply that a significant part of the carboniferous sequence became eroded only during early cretaceous times and or that the jurassic heat flow was significantly increased 90 mw m2 elevated heat flows may be related to jurassic magmatic activity sediments in the southern donbas foldbelt yuzhno donbassky region and the westernmost krasnoarmeisk monocline record cooling below 60 c during jurassic times whereas samples northeast of donetsk cooled below 60 c during cretaceous times a correlation between this last cooling and the present day depths of the samples suggests that the main episode of folding along the south syncline and the south anticline pre dates cretaceous cooling

germanium silicon fractionation in the weathering environment abstract we present a detailed study of germanium behavior in the soil weathering environment as an important step toward using the ge si system as a tracer of silicate weathering processes in both modern and ancient environments intensely weathered soils developed on hawaiian basalts have bulk soil ge si ratios 2 to 10 times higher than fresh basalt e g 10 to 25 mol mol vs 2 5 mol mol soil ge concentrations increase with si and decrease with fe suggesting that ge sequestration is related to accumulation of secondary soil silicates rather than retention in soil fe oxy hydroxides sequential extractions of these soils suggest that ge si fractionation takes place by ge sequestration during the initial precipitation of secondary soil aluminosilicates principally allophane further si loss and changes in mineralogy as these soils age result in little additional ge si fractionation ge si ratios in granitic soils and saprolites are strongly influenced by relative weathering rates of primary minerals kaolinite has a ge si ratio 5 9 mol mol higher than the plagioclase from which it forms 3 1 mol mol whereas accumulation of primary quartz ge si 0 5 mol mol prevents granitic soils from attaining high ge si ratios laboratory synthesis of allophane confirms that ge is preferentially partitioned into the solid phase upon precipitation of secondary aluminosilicates from solution

the donets basin ukraine russia coalification and thermal history the donets basin donbas is one of the major late paleozoic coal basins in the world the donbas foldbelt is an inverted part of the donets basin characterized by wnw ese trending folds and faults the age of basin inversion is under discussion large parts of the donets basin host anthracite and meta anthracite low rank coals are restricted to the western and northern basin margins vitrinite reflectance patterns along the gorlovka anticline indicate syn deformational coalification vitrinite reflectance isolines are displaced along thrusts clear evidence that main coalification predates late faulting 1 d and 2 d numerical models were applied to elucidate the factors that control coalification in the western donets basin krasnoarmeisk monocline kalmius torets depression south syncline the models indicate that the depth of the seams and the heat flow during maximum permian burial are the most important parameters the thickness of late carboniferous and permian rocks increased from the southwestern basin margin towards the basin center permian erosion along the krasnoarmeisk monocline and in the kalmius torets depression was on the order of 2 3 km more rocks were eroded southeast of the donetsk kadievka fault zone 4 5 km heat flow during maximum burial was in the range of 40 75 mw m2 heat flow in the krasnoarmeisk monocline and the kalmius torets depression increased in a northeastward direction from 40 to 55 mw m2 heat flow at the eastern edge of the kalmius torets depression and in the south syncline was in the range of 60 75 mw m2 and increased towards the southeast the resulting coalification pattern in this area was overprinted by thermal events in the northern krasnoarmeisk monocline and the south syncline these are probably related to permian magmatic intrusions coked coal occurs at the contact to presumed permian sills and dikes southwest of donetsk

stratigraphy and sequence stratigraphy of the moscovian in the donets basin new results are presented on the stratigraphy based on fusulinids and palynomorphs and the sequence stratigraphy of the moscovian in the donets basin they have been developed by comparison of our observations on cross sections near artemovsk and the published coal mine logs of artemovsk geological survey the moscovian of the donets basin is equivalent to the uppermost westphalian b and the westphalian c and d of western europe in the donets basin the moscovian forms a second order sequence as in the moscow basin that can be subdivided into four third order sequences subdivided into fourth order sequences the upper bashkirian shows two fourth order sequences the vereian exhibits two fourth order sequences the kashirian shows four fourth order sequences the podolskian offers eight fourth order sequences the myatchkovian presents four fourth order sequences these sequences begin with an erosive base and show a succession of elementary sequences with fluvial sandstone coal seam limestone and deltaic facies the fluvial sandstone corresponds with an aggradation period the coal and the limestone with a transgressive period and the deltaic facies with a progradation period a decrease of the sandstone thickness and an increase of the marine deposits that are transgressive and regressive upwards are observed from the base to the top of sequences these fourth order sequences present a higher spatial amplitude than the third order sequence and obscure these sequences the second order sequence equivalent to the moscovian shows a lowstand system tract with more fluvial sandstone in the lower part of the vereian a transgressive system tract in the upper part of the vereian tsinskaya and kashirian a maximum flooding period during the podolskian and lower part of the myatchkovian with more marine facies and a highstand system tract in the upper part of the myatchkovian with more lagoonal and swampy palaeoenvironments the sequences are controlled by the regional tectonic subsidence in the graben and the uplift of the horsts and or by eustasy with either a plate tectonic or a glacial origin other investigations particularly radiometric dating will be useful for solving this problem

shale gas shale oil potential of upper visean black shales in the dniepr donets basin ukraine abstract upper visean rudov beds v 23 are considered as one of the main source rocks within the northwestern dniepr donets basin ddb average toc values within the srebnen bay northwestern ddb exceed 4 thickness up to 100 m average toc contents north and northwest of the srebnen bay up to 60 m are significantly lower 2 4 but still sufficient for unconventional hydrocarbon production whereas wells along the northeastern basin margin do not hold a shale oil gas potential 5 5 km although hydrogen index hi values of the most immature samples are 300 mghc gtoc basinal rudov beds host a potential to generate paraffinic naphthenic aromatic p n a low wax oil according to pyrolysis experiments a basinward maturity trend is visible but the maturity cut offs for shale oil gas production 0 8 rr 1 2 rr are reached at great depths 4 5 km 5 5 km only furthermore results of kinetic experiments do not argue for presence of type iis kerogen potentially triggering earlier hydrocarbon generation the mineralogy of rudov beds varies strongly in lateral and vertical directions limiting the predictability of mechanical behaviour samples from the siliceous basinal facies partly contain more than 60 of brittle minerals quartz feldspar carbonates etc suggesting a good fraccability this value is rarely reached by samples from the transitional and lagoonal calcareous and clayey facies the clay mineral fraction within many investigated rudov samples is dominated by kaolinite which is suggested to diminish the fraccability of shales apart from that expandable clay minerals ecm are present in samples from more than 5 km depth a result of low mesozoic heat flow

instantaneous outbursts in underground coal mines an overview and association with coal type instantaneous outbursts in underground coal mines have occurred in at least 16 countries involving both methane ch4 and carbon dioxide co2 the precise mechanisms of an instantaneous outburst are still unresolved but must consider the effects of stress gas content and physico mechanical properties of the coal other factors such as mining methods e g development heading into the coal seam and geological features e g coal seam disruptions from faulting can combine to exacerbate the problem prediction techniques continue to be unreliable and unexpected outburst incidents resulting in fatalities are a major concern for underground coal operations gas content thresholds of 9 m 3 t for ch4 and 6 m 3 t for co2 are used in the sydney basin to indicate outburst prone conditions but are reviewed on an individual mine basis and in mixed as situations data on the sorption behaviour of bowen basin coals from australia have provided an explanation for the conflicting results obtained by coal face desorption indices used for outburst proneness assessment a key factor appears to be different desorption rates displayed by banded coals which is supported by both laboratory and mine site investigations dull coal bands with high fusinite and semifusinite contents tend to display rapid desorption from solid coal for a given pressure drop the opposite is true for bright coal bands with high vitrinite contents and dull coal bands with high inertodetrinite contents consequently when face samples of dull fusinite or semifusinite rich coal of small particle size are taken for desorption testing much gas has already escaped and low readings result the converse applies for samples taken from coal bands with high vitrinite and or inertodetrinite contents in terms of outburst potential it is the bright vitrinite rich and the dull inertodetrinite rich sections of a coal seam that appear to be more outburst prone this is due to the ability of the solid coal to retain gas even after pressure reduction creating a gas content gradient across the coal face sufficient to initiate an outburst once the particle size of the coal is reduced rapid gas desorption can then take place c 1998 elsevier science

comment on sequence stratigraphy and onlap history of the donets basin ukraine insight into carboniferous icehouse dynamics by j m eros i p montanez d a osleger v i davydov t i nemyrovska v i poletaev and m v zhykalyak palaeogeography palaeoclimatology palaeoecology 313 314 2012 1 25 abstract each high quality regional study of relative sea level changes may contribute to the understanding of global eustatic mechanisms in particular it is intriguing to compare the carboniferous sea level changes established in the donbass a large domain in the southwest of russia and the east of ukraine by eros et al 2012 with the available global eustatic curve at least two significant discrepancies between these reconstructions are found the long term early moscovian lowstand that is reported from the donbass coincides with the global eustatic rise in contrast the early bashkirian global sea level lowstand occurred when the relative sea level did not experience any extraordinary fall in the donbass sea level fluctuations across the mississippian pennsylvanian boundary also differed slightly at other time intervals the regional and global curves are comparable it is possible to hypothesize that either the regional signatures of the global eustatic fluctuations were altered by tectonic activity e g in the form of dynamic topography or that the available eustatic curve is incorrect in some places only further broad inter regional correlations of carboniferous sequences will permit choosing between these hypotheses and it is not excluded that some different conclusions would be drawn if the observed stratigraphy of the donbass is instead caused by regional vertical tectonic motions

the 40ar 39ar dating of magmatic activity in the donbas fold belt and the scythian platform eastern european craton 1 the donbas fold belt is the compressionally deformed southeasternmost part of the intracratonic late paleozoic dniepr donets rift basin it is situated in an intracratonic setting but close to the southern margin of the east european craton south of which lies the scythian platform a range of igneous rocks from the donbas fold belt and the scythian platform were dated by the 40ar 39ar method in order to constrain the ages of magmatic activity in these areas and compare them the plateau ages from the south margin of the donbas fold belt vary from 151 4 4 7 ma to 278 1 5 3 ma and define three main age groups middle late jurassic middle late triassic and early permian the age spectra obtained from the scythian platform samples are often disturbed as a result of limited alteration the proposed ages plateau and pseudoplateau vary from 174 4 2 1 ma to 243 7 1 4 ma and two major age groups are defined in early carboniferous and triassic jurassic times the early permian 285 270 ma and early triassic 245 250 ma ages of magmatic activity are the same in both areas in the late triassic the ages of magmatic activity are slightly different 220 and 205 ma and they are entirely different thereafter these data can be interpreted as indicating a mantle plume as common deep magmatic source

crustal scale pop up structure in cratonic lithosphere dobre deep seismic reflection study of the donbas fold belt ukraine the dobre project investigated the interplay of geologic and geodynamic processes that controlled the evolution of the donbas fold belt ukraine as an example of an inverted intracratonic rift basin a deep seismic reflection profile provides an excellent image of the structure of the donbas fold belt which is the uplifted and compressionally deformed part of the late paleozoic pripyat dniepr donets basin both the effects of rifting and those of later structural inversion are recognized in the seismic and geologic data the interpretation of the reflection data shows that the inversion of the donbas fold belt occurred at the crustal scale as a mega pop up which involved a major detachment fault through the entire crust and an associated back thrust the dobreflection image provides a simple concept of intracratortic basin inversion the crustal pop up being uplifted and internally deformed the association of such a structure with inverted intracratonic basins such as the donbas fold belt implies brittle deformation of relatively cold crust

light and trace element composition of carboniferous coals from the donets basin ukraine an electron microprobe study abstract the ukrainian donets basin donbas is one of the major coal mining provinces worldwide while the depositional setting of donbas coals is well studied information on modes of trace element occurrence and changes in element composition with increasing maturation is lacking within the frame of the present study both major light elements c o s and trace elements e g as cu hg mo pb were investigated using the electron microprobe epma which allows in situ determination of the chemical composition of a maceral or mineral phase deviating maturity trends in c o and s contents were found for different maceral groups in relatively immature samples 0 9 rr s contents of vitrinites and liptinites are comparable but lower in inertinite macerals vitrinites in a marine influenced coal host a higher amount of organic s whereas the trace element concentrations are lower than in the investigated non marine coals as expected a trend of increasing c and decreasing o contents was observed for vitrinite macerals within a maturity range from 0 5 to 1 4 rr referred to a decrease in volatile compounds during thermal maturation the light element composition generally tends to higher homogenity with increasing coal rank highly variable trace element concentrations of ash residues were determined for donbas coals with measured as contents up to several thousand ppm despite enrichment in epigenetic pyrite a clearly isolated inorganic source could not be identified suggesting that trace element storage in macerals is an important factor epma measurements revealed an organic matter affinity for at least part of the investigated elements e g hg mo pb

the donbas foldbelt its relationships with the uninverted donets segment of the dniepr donets basin ukraine abstract the donbas foldbelt df is a thrust faulted and folded inverted segment of the dniepr donets basin ddb it lies between the scythian and east european platforms north of the black sea and is conventionally thought to have formed in the early permian as part of the late palaeozoic hercynian uralian orogenic frame of cratonic europe the ddb itself formed as a result of late devonian intracratonic rifting and contains a thick up to 22 km late palaeozoic and mesozoic sedimentary succession the deformed strata preserved at the erosional surface of the df are mainly carboniferous the donets segment of the ddb displays mild inversion structures that are transitional to those in the df recently acquired regional seismic reflection data in the donets part of the ddb allow these structures to be imaged in the subsurface for the first time a widespread early permian unconformity occurring throughout the ddb is much more pronounced on its southern margin than on its northern one and appears to be related to profound uplift of the southern flank of the basin and the neighbouring ukrainian shield rather than to crustal shortening faults associated with the early permian unconformity are extensional in style gentle folds and other local structures in the southern flank and axis of the donets segment are mainly located in areas associated with early permian salt movements no significant development of compressional structures of early permian age can be seen in the seismic data where it is available in contrast there is ample evidence of latest cretaceous earliest tertiary compressional deformation in the ddb including the subsurface expression of structures along strike of the main folds of the df a review of geological evidence in the df also indicates that the main period of shortening that can be definitely constrained in time is latest cretaceous earliest tertiary the eastern part of the df records intense late triassic aged cimmerian deformation but none of clearly permian age it is tentatively concluded that the main phases of trans compressional tectonics forming the df were cimmerian and especially alpine rather than hercynian uralian

sequence stratigraphy and onlap history of the donets basin ukraine insight into carboniferous icehouse dynamics abstract the degree to which permo carboniferous cyclothemic successions archive evidence for long term variations in ice volume during the late paleozoic ice age is insufficiently resolved here we develop the sequence stratigraphy and onlap offlap history for a 33 my interval of the carboniferous using the u pb calibrated succession of the donets basin ukraine in order to assess the relationship between sea level high latitude changes in glacial extent and climate integrated subsurface and outcrop data permit meter scale correlation of 242 biostratigraphically constrained limestones and coals and in turn individual cyclothems across 250 km of the donets basin rapid uniform subsidence and basinwide continuity of marker beds indicate pennsylvanian deposition under relatively stable tectonic conditions three scales of sequences avg durations of 140 ky 480 ky and 1 6 my are recognized on the basis of stratigraphic stacking patterns and basinwide architecture of marine to terrestrial facies assemblages the hierarchy of sequences and the geographic and stratigraphic positions of shifts in base level sensitive facies across the donets ramp permit the construction of an onlap offlap history at a sub 400 ky scale major sea level lowstands occur across the mid carboniferous boundary and during the early moscovian these lowstands coincide with glacial maxima inferred from high latitude glacigenic deposits the middle to late pennsylvanian is characterized by a stepwise onlap culminating in an earliest gzhelian highstand suggesting contraction of carboniferous ice sheets prior to the initiation of early permian glaciation the stratigraphic position of climate sensitive facies within individual donets cyclothems indicates a turnover from seasonal sub humid or semi arid climate to everwet conditions during the late lowstand and maximum ice sheet accumulation comparison of the stratigraphic and aerial distribution of coals and evaporites in the donets basin with the onlap offlap history further indicates everwet conditions during lowstands and inferred glacial maxima and drier climate during onlap and inferred ice sheet contraction at the intermediate 0 8 to 1 6 my and long 106 yr time scales taken together the relationship between inferred climate and glacioeustasy suggests a likely teleconnection between high latitude ice sheet behavior and low latitude atmospheric dynamics

style and timing of salt tectonics in the dniepr donets basin ukraine implications for triggering and driving mechanisms of salt movement in sedimentary basins abstract the ukrainian dniepr donets basin ddb is a late palaeozoic intracratonic rift basin with sedimentary thicknesses up to 19 km displaying the effects of salt tectonics during its entire history of formation from late devonian rifting to the tertiary hundreds of concordant and discordant salt structures formed during this time it is demonstrated in this paper that the variety of styles of salt structure formation in the ddb provide important constraints on understanding the triggering and driving mechanisms of salt kinematics in sedimentary basins in general salt movement in the ddb began during the devonian syn rift phase of basin development and exerted controls on the later distribution of salt structures though the geometry of basement faults is not directly responsible for the regular spacing of salt structures post rift salt movements in the ddb occurred episodically episodes of salt movement were triggered by tectonic events specifically two extensional events during the carboniferous an extensional reactivation at the end of carboniferous earliest permian and a compressional event at the end of the cretaceous extensional events that induced salt movement were thick skinned i e basement involved in deformation rather than thin skinned most overburden deformation related to salt movements is ductile regardless of sedimentary bulk lithology and degree of diagenesis while the deformation of sedimentary cover in areas where salt is absent is mainly brittle this implies that the presence of salt changes the predominant mode of deformation of overlying sedimentary rocks episodes of salt movement lasted longer than the periods of active tectonics that initiated them buoyancy erosion and differential loading all played a role in driving halokinesis once tectonic forces had pushed the salt overburden system into disequilibrium among these factors erosion of overburden above growing salt structures acted as a key self renewing force for development of salt diapirs very high sedimentation rates related to high post rift tectonic subsidence rates particularly during the carboniferous were able to bury diapirs and to load salt bodies such that buoyancy erosion and differential loading forces eventually became insufficient to continue driving diapirism until the system was perturbed by an ensuing tectonic event in contrast some salt anticlines and diapirs developed continuously during the entire mesozoic because of much reduced tectonic subsidence rates and sedimentation supply during this time however a lower permian salt series and overhangs of buried diapirs played an important role in preventing overburden piercing and fracturing during the mesozoic and specifically during the late cretaceous salt diapirism phase

mercury and trace element contents of donbas coals and associated mine water in the vicinity of donetsk ukraine abstract mercury rich coals in the donets basin donbas region of ukraine were sampled in active underground mines to assess the levels of potentially harmful elements and the potential for dispersion of metals through use of this coal for 29 samples representing c 11 to m 3 carboniferous coals mercury contents range from 0 02 to 3 5 ppm whole coal dry basis mercury is well correlated with pyritic sulfur 0 01 to 3 2 wt with an r 2 of 0 614 one outlier excluded sulfides in these samples show enrichment of minor constituents in late stage pyrite formed as a result of interaction of coal with hydrothermal fluids mine water sampled at depth and at surface collection points does not show enrichment of trace metals at harmful levels indicating pyrite stability at subsurface conditions four samples of coal exposed in the defunct open cast nikitovka mercury mines in gorlovka have extreme mercury contents of 12 8 to 25 5 ppm this coal was formerly produced as a byproduct of extracting sandstone hosted cinnabar ore access to these workings is unrestricted and small amounts of extreme mercury rich coal are collected for domestic use posing a limited human health hazard more widespread hazards are posed by the abandoned nikitovka mercury processing plant the extensive mercury mine tailings and mercury enrichment of soils extending into residential areas of gorlovka

pangea b and the late paleozoic ice age abstract the late paleozoic ice age lpia was the penultimate major glaciation of the phanerozoic published compilations indicate it occurred in two main phases one centered in the late carboniferous 315 ma and the other in the early permian 295 ma before waning over the rest of the early permian and into the middle permian 290 ma to 275 ma and culminating with the final demise of alpine style ice sheets in eastern australia in the late permian 260 to 255 ma recent global climate modeling has drawn attention to silicate weathering co2 consumption of an initially high greater variscan edifice residing within a static pangea a configuration as the leading cause of reduction of atmospheric co2 concentrations below glaciation thresholds here we show that the best available and least biased paleomagnetic reference poles place the collision between laurasia and gondwana that produced the greater variscan orogen in a more dynamic position within a pangea b configuration that had about 30 more continental area in the prime equatorial humid belt for weathering and which drifted northward into the tropical arid belt as it transformed to pangea a by the late permian the presence of widespread equatorial coal basins with euramerica flora in the footprint of the greater variscan orogen during the late carboniferous is more compatible with a heterogeneous horst and graben morphology characterized by uplifted crystalline massifs acting as loci of intense silicate weathering co2 consumption and supplying sediment for proximal basins as venues of organic carbon burial than a contiguous high mountain plateau as assumed in recent climate modeling of the lpia and its demise the culminating phase of the lpia occurred at about 275 ma with the transformation from pangea b to pangea a and the attendant reduction of continental area in the equatorial humid belt as well as with continued northward drift that placed what remained of the greater variscan orogen into the zechstein arid belt in the late permian by which time the geologic landscape was largely blanketed with siliciclastics the resulting warming from reduced silicate weathering and thus increasing pco2 was interrupted at 260 ma with a cooling trend that coincided with emplacement of the emeishan large igneous province on the equatorial south china craton as well as the drift of the cimmerian continental blocks through the equatorial humid belt due to opening of the neo tethys a return to ice age conditions from the increase in silicate weathering uptake of co2 was avoided by drift of the emeishan large igneous province out of the equatorial belt that in conjunction with massive outgassing from emplacement of the siberian traps in high latitudes at the end of the permian 252 ma helped steer the climate system to sustained non glacial conditions

predicting methane accumulations generated from humic carboniferous coals in the donbas fold belt ukraine the numerical modeling of the ukrainian part of the donbas fold belt indicates that the coalification pattern was controlled mainly by the maximum burial depth of coal seams and the heat flow hf 40 75 mw m2 during the permian the coalification pattern was overprinted by magmatic events during the late permian in the south syncline 150 mw m2 and during the permian triassic in the north of the krasnoarmeisk region 120 mw m2 the coalification pattern shows a strong increase in vitrinite reflectance values toward the east and southeastern parts of the study area likely caused by 1 an eastward increase in burial depth 2 a probable eastward increase in hf and 3 probable magmatic activity an increase in total erosion toward the eastern and southeastern parts was also observed with a maximum erosional amount of approximately 8 km 5 mi in the southeastern part of the study area the basin modeling of this area predicts that the main phase of hydrocarbon generation occurred during the carboniferous early permian subsidence the magmatic events that occurred during the permian triassic caused renewed pulses of hydrocarbon generation a large amount of the generated hydrocarbons was lost to the surface because of a lack of seals however the numerical simulation predicts accumulations of about 2 tcf 57 billion m3 of methane generated from carboniferous coals in the south and main synclines where lower permian seal rocks are preserved finally this study provides data on methane resources along the northern flank of the basin which remains a significant frontier for natural gas exploration

germanium silicon ratios in the copper river basin alaska weathering and partitioning in periglacial versus glacial environments 1 glacial to interglacial variation in the germanium to silicon ratio ge si of biogenic opal in oceanic sediment cores has been proposed to record terrestrial silicate weathering intensity however data connecting ge si ratios to weathering are sparse especially for cold regions to characterize ge si of the dissolved loads of rivers draining modern glacial and periglacial regions we measured ge and major element chemistry of more than 30 streams in the copper river basin of south alaska we measured significantly higher ge si in rivers with greater than 15 glacial cover in their basins than in rivers draining areas with less glacial cover which we attribute to preferencial subglacial weathering of biotite we also ran laboratory experiments to investigate the role of differential sorption of ge and si on hydrous iron oxides in moderating the ge si ratio of rivers in recently deglaciated basins these experiments indicate that ge is preferentially adsorbed over si by hydrous iron oxides over a wide range of ph values and support differential sorption as a potentially significant fractionation process our measured high ge si in glaciated basins is in striking contrast to the low ge si in the oceanic record during glacial periods the glacial to interglacial changes in marine ge si cannot simply reflect changes in glacier cover on land as the mineralogy of silicates weathered and processes partitioning ge in soils must also strongly influence the fluvial ge and si inputs to the ocean

basin evolution and coal geology of the donets basin ukraine russia an overview abstract the donets basin is a major coal mining district in eastern ukraine and adjacent portions of russia it comprises the donbas foldbelt which is the uplifted and compressionally deformed part of the pripyat dniepr donets pdd basin and the significantly less deformed western donbas region the pdd basin is a late devonian rift structure located within the east european craton thick coal measures formed during the post rift stage of the basin in serpukhovian to moscovian times when about 130 seams each with a thickness over 0 45 m have been deposited early serpukhovian coal accumulated in a relatively narrow shore zone it is rich in inertinite and liptinite and very low in ash bashkirian and moscovian coal have a significantly wider lateral extension and are generally rich in vitrinite bashkirian and moscovian coal seams usually have high ash yields 12 18 and high sulfur contents 2 5 3 5 but these data vary significantly depending on peat facies coal rank ranges from subbituminous to anthracite and is mainly controlled by the depth of the seams and the heat flow during maximum permian burial permo triassic thermal events locally overprinted the resulting coalification pattern coked coal occurs at the contact to presumed permian sills and dikes southwest of donetsk deep permian burial was followed by major permian and mesozoic uplift events the donets basin hosts proven reserves in the order of 60 gt at the exploitable depth the thickness of coal seams currently mined is in the range of 0 6 to 2 5 m production during 2009 was 68 7 mt in the ukrainian and 4 9 mt in the russian part of the basin coal mines in the donets basin are among the gassiest in the world the average methane content of coal is 14 7 m t but numerous seams have significantly higher gas content the high methane content presents a severe mine safety problem on the other hand it represents also a high potential for coal mine bed methane projects emissions of coal gas released by mining and related structurally induced underground hazards coal and gas outbursts are a major problem for safe and efficient coal exploitation in the basin

petrography and geochemistry of carboniferous coal seams in the donets basin ukraine implications for paleoecology abstract the carboniferous succession in the donets basin hosts about 130 seams each with a thickness over 0 45 m nine economically important seams from the south western donets basin are studied using organic petrographical inorganic geochemical and organic geochemical techniques the main aim of the study is the reconstruction of peat facies of serpukhovian mississippian and moscovian middle pennsylvanian coals formation of major coal seams commenced during serpukhovian times early serpukhovian coal accumulated in a relatively narrow shore zone and is rich in inertinite and liptinite very low ash yields low to moderate sulphur contents and upward increasing inertinite contents suggest coal deposition in raised mires moscovian coal has a significantly wider lateral extension and is generally rich in vitrinite coal properties vary widely in response to different peat facies low sulphur low ash k 7 coal was formed in a raised mire or in a low lying mire without detrital input l 1 and l 3 seams containing several fluvial partings were formed in low lying mires both seams are more than 2 m thick seams m 2 and m 3 contain high sulphur coal a consequence of deposition in a peat with marine influence in contrast syngenetic sulphur content is low in the m 5 1 upper seam which was formed in a lacustrine setting the late moscovian n 1 seam up to 2 4 m thick accumulated in a swamp with a vegetation rich in bryophytes and pteridophytes the properties of the n 1 seam are transitional between those of serpukhovian and other moscovian seams differences in maceral composition between serpukhovian and moscovian coals probably reflect changes in climate and vegetation type tuff layers are observed in the l 1 l 3 and m 3 seams the l 3 and m 3 seams contain abundant authigenic quartz trace element contents are high in many seams as contents are especially high in seams c 10 2 k 7 l 3 and m 3 ash in the l 3 seam contains up to 8000 ppm as co is enriched near the base of several seams maxima up to 2400 ppm occur in the ash of the k 7 and l 3 seams cd contents in ash are frequently as high as 30 or 40 ppm

early diagenesis of germanium in sediments of the antarctic south atlantic in search of the missing ge sink pore water and solid phase geochemistry profiles were obtained from several cores between 41 degree s and 53 degree s in the atlantic sector of the southern ocean pore water nitrate manganese and iron profiles delineate standard redox zones in these sediments and help characterize those with classic vs burn down behaviors pore water si and ge profiles demonstrate that ge released during opal dissolution is removed pervasively throughout the uppermost interval of silicate release and also downwards into the suboxic zone by as yet unidentified precipitation mechanisms these results indicate that early diagenesis of ge is uncoupled from that of opal solid phase extractions fe mn u mo ge cu ni co v and cd in a few cores suggest that anthigenic ge removal in the suboxic zone is not associated with peaks in authigenic mn cycling mno sub 2 and related metals but rather with processes deeper in the sediments perhaps fe or u diagenesis below the interval of ge removal pre water ge increases linearly with depth by over two orders of magnitude indicating a deep below recovery source of large magnitude the fraction of opal derived ge precipitated authigenically in these sediments ranges from approximately 1 to 96 and correlates strongly with the detrital fraction asmore well as the detrital to opal ratio both of which generally decrease from north to south the ge sink observed in these sediments would need to be globally representative to account for the entire missing ge sink in today s oceanic ge balance which seems unlikely benthic fluxes of ge and si estimated from these pore water profiles and from measurements in three benthic flux chamber experiments at high carbon rain continental margin sites demonstrate that the ge si rate released from the seafloor in locations with high benthic silicate and carbon fluxes is congruent with holocene opal dissolution ge si approximately 0 7 x 10 sup minus 6 in contrast ge si flux ratios in areas with low silicate fluxes are ge depleted ge si 0 5 x 10 sup minus 6 the authors speculate that glacial interglacial changes in oceanic ge si as recorded in diatoms may be due in part to variations in this authigenic ge sink perhaps related to shifts in siliceous productivity from open ocean antarctic siliceous oozes during interglacials to areas of higher detrital input sub antarctic continental margins and possibly also to generally more reducing conditions in sediments during glacials less

the geochemistry of inorganic germanium in natural waters we present the initial results from a survey of the distribution of dissolved inorganic germanium in rivers in the oceans and in hydrothermal vents and plumes in the ocean germanium cycling mimics that of silica since siliceous organisms incorporate ge as a trace constituent in biogenic opal the vertical and horizontal distributions of ge concentrations in seawater are thus identical to those of silica ge si 0 7 10 6 and reflect uptake into and dissolution from the frustules of siliceous organisms germanium enters the ocean via dissolution of continental and seafloor silicates the naturally weathered flux from continents to oceans carries a dissolved ge si atom ratio in rivers of about 0 7 10 6 which reflects the ratio in average continental granites rivers draining industrial regions with significant coal combustion are contaminated with ge leached from fly ash particles resulting in ge si ratios up to tenfold above the naturally weathered background the flux to the oceans via high temperature alteration of seafloor basalts hot springs produces a ge anomaly in hydrothermal plumes over the east pacific rise crest 20 s combining the observed ge and 3he anomalies in plumes with 3he si observations in hot springs suggests that the ge si hydrothermal flux to the oceans is about 4 10 6 near the ratio for average oceanic basalts 2 6 10 6 vent effluents from the galapagos hot springs measured directly display ge si ratios of 16 10 6 suggesting that the ratio is variable between vent fields metalliferous sediments accumulating on the epr crest 17 s are enriched in germanium suggesting that a fraction of the hydrothermal germanium source on the rise crest is scavenged into these rapidly accumulating iron and manganese hydroxyoxide phases

a study of hydrogeology and its effect on coalbed methane enrichment in the southern junggar basin china this paper analyzes regional hydrogeological conditions and divides the study area into three hydrogeological types and seven hydrogeological units to investigate hydrogeology and its effect on coalbed methane cbm enrichment in the southern junggar basin china from this work it is found that the groundwater flow paths in the study area are the joint effects of south to north and west to east flows this study also shows that microbial gases are widely developed although the depth limit of microbial gas occurrence is still unclear in the study area microbial co2 reduction is the leading formation path in the study area except for the houxia region where fermentation is the formation mechanism the abnormally high co2 in stagnant zones i e water flow is slow and stagnant is mainly associated with methanogenesis whereas relatively low co2 microbial or thermogenic is present where water flow is active the average cbm content within the xishanyao formation changes within various hydrogeological units moreover the average cbm content within the badaowan formation of the same hydrogeological unit e g fukang suggests that the hydrogeological and cbm enrichment conditions are different within various structural types overall the hydrogeological conditions exert control on the gas content in the study area that is the gas content is high in stagnant zones finally influenced by supplemental microbial gases changes in the cbm oxidation zone are relatively complex in the study area the depth of which has no obvious correlation with hydrogeological conditions and changes significantly from west to east

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

oil gas source rock correlations in the dniepr donets basin ukraine new insights into the petroleum system abstract the dniepr donets basin ddb hosts a multi source petroleum system with more than 200 oil and gas fields mainly in carboniferous clastic rocks main aim of the present study was to correlate accumulated hydrocarbons with the most important source rocks and to verify their potential to generate oil and gas therefore molecular and isotopic composition as well as biomarker data obtained from 12 oil and condensate samples and 48 source rock extracts was used together with usgs data for a geological interpretation of hydrocarbon charging history within the central ddb results point to a significant contribution from upper visean black shales highly oil prone as well as mixed oil and gas prone serpukhovian rocks and minor contribution from an additional tournaisian source devonian rocks an important hydrocarbon source within the pripyat trough have not been identified as a major source within the central ddb additional input from bashkirian to moscovian shebelinka field as well as tournaisian to lower visean rocks e g dovgal field with higher contents of terrestrial organic matter is indicated in the se and nw part respectively whereas oil source correlation contradicts major hydrocarbon migration in many cases for tournaisian to middle carboniferous reservoir horizons accumulations within upper carboniferous to permian reservoirs require vertical migration up to 4000 m along faults related to devonian salt domes 1 d thermal models indicate hydrocarbon generation during permo carboniferous time however generation in coal bearing middle carboniferous horizons in the se part of the basin may have occurred during the mesozoic

terrestrial paleorecords of ge si cycling derived from lake diatoms abstract modern river studies support the generalization that surface waters in regions undergoing extensive chemical weathering have elevated dissolved germanium silicon ge si ratios compared to regions with less extensive chemical weathering thought to be the result of ge fractionation in 2 1 clays temporal variations in ge si observed in marine diatoms have thus been linked to past global trends in terrestrial weathering however this relationship has not been adequately ground truthed by a terrestrial based paleoclimate study utilizing ge si ratios in lake diatoms to this end a sediment core was extracted from dry lake el 2763 m in the headwaters of the santa ana river of southern california in july 1996 the dry lake drainage basin is comprised of biotite muscovite gneiss and granite with sparse pine forests and relatively high relief the core had a basal ams 14c age of 8 350 60 ybp we successfully separated diatom samples large enough for cleaning dissolution and chemical analysis without contamination by detrital materials confirmed by trace metal analyses two dissolved opal samples were analyzed for ge and si concentrations along with modern water samples collected from waters within the drainage basin diatoms obtained from 8000 year old sediments near the bottom of the core had an opal ge si of 0 79 10 6 mol mol a composite sample of diatoms deposited within the past 100 years yielded a significantly lower ge si of 0 34 10 6 analysis of ge si was also performed from a variety of other materials in the dry lake basin including stream and lake water unweathered bedrock soils and mineral separates together with sedimentologic records from the lake sediments and ge si recorded in other basin materials it appears that the high ge si values recorded in the 8000 year opal sample were the result of preferential early weathering of high ge si biotite and muscovite minerals from the slopes thus the detailed examination of ge si cycling in this isolated basin indicates that factors other than clay mineral transformations may drive ge si paleorecords in some settings

stratigraphic distribution of macerals and biomarkers in the donets basin implications for paleoecology paleoclimatology and eustacy abstract more than one hundred and thirty coal seams and coaly layers occur in the donets basin donbas twenty eight 52 samples of them ranging in age from serpukhovian late mississipian to gzhelian late pennsylvanian 33 clastics and three limestones were studied in terms of maceral composition sulphur contents and biomarker distribution diterpanes are used to estimate the contribution of different groups of plants and the height of the water table in the swamp hopanes are a measure of bacterial activity in the peat and steranes indicate the relative input of wood and algae stratigraphic trends in these parameters are discussed in relation to paleoenvironment climatic changes and eustacy a tropical climate prevailed in the donbas from serpukhovian to kasimovian times nevertheless periods with drier and wetter conditions can be distinguished based on maceral and biomarker data relatively dry conditions are observed during serpukhovian and vereian times whereas wetter climates with a maximum of coal deposition occurred during the late bashkirian most of the moscovian and the earliest kasimovian no economic coal seams are hosted in upper kasimovian and gzhelian deposits a result of a change to an arid climate our data also suggest climatic changes during sequences of different order for the second order third order and fourth order sequences relatively dry or wet conditions occurred during coal deposition in the lowstand systems tract an intermediate climate during the transgressive systems tract and the maximum flooding and a wet climate during the highstand systems tract the results for high frequency sequences support the cecil s paleoclimatic model an intermediate paleoclimate during lst sandstone and levee siltstone a wet climate during early tst coal and a dry climate during late tst limestone mfs claystone and hst deltaic siltstone coals deposited during maximum flooding periods are more enriched in c27 steranes derived from algae and contain lower proportions of c29 steranes derived from the wood of higher plants

dnieper donets palaeorift abstract the devono carboniferous intra cratonic dnieper donets palaeorift transects the southwestern part of the east european platform in a nw se direction it is characterized by linear bounding faults penetrating much of the crust substantial crustal thinning and syn rift volcanic activity the dnieper donets rift developed on cold precambrian shield type continental crust its rifting stage spans early frasnian to late visean times during its post rift evolution an elongate saucer shaped basin subsided the axis of which coincides with the trace of the underlying rift the palaeozoic donets rift is superimposed on a late proterozoic rift a thermal perturbance of the asthenosphere is thought to have provided the driving mechanism for the development of the palaeozoic dnieper donets rift rapid thinning of the subcrustal lithosphere in response to advecting asthenospheric melt was coupled with tensional fracturing of the crust and melting of its lower part this caused an upward displacement of the moho discontinuity post rift subsidence of the dnieper donets graben was governed by lithospheric cooling the southeastern parts of this rift system were inverted during the uralian orogeny

comparison of generative capacities for bitumen and gas between carboniferous coals from donets basin ukraine and a cretaceous coal from sabinas piedras negras basin mexico during artificial maturation in confined pyrolysis system abstract the goal of this work is to study the ability of two immature carboniferous coals from donets basin ukraine to act as source for oil heating experiments in confined medium were performed to compare the thermal behavior of these coals 1l1 dim r r 0 55 h c at 0 79 and 2c10yd r r 0 65 h c at 0 80 relative to a mature cretaceous coal from sabinas basin olmos r r 0 92 h c at 0 77 macerals analysis carried out on starting materials showed that olmos is exhausted in liptinite contrary to 2c10yd 20 vol and 1l1dim 6 vol the vitrinite content is lower for 2c10yd 59 vol than for olmos 84 vol and 1l1dim 80 vol solid bitumen occurs often dispersed in the raw coals both petrographic and geochemical analyses on starting materials revealed that the selected carboniferous donets coals have better potentialities for bitumen generation than the cretaceous sabinas coal the presence of long chain n alkanes n c 8 in the pyrolysis gc chromatograms indicates that the two raw carboniferous coals from donets basin can yield non volatile hydrocarbons under further thermal maturation it is speculated that some vitrinite macerals present in hydrogen rich carboniferous coals from donets basin can act as source rocks for oil as a matter of fact results showed that the oil window occurs between 1 0 r r and 2 0 r r for both cretaceous sabinas and carboniferous donets coals during confined pyrolysis as expected from geochemical and petrographic analyses of starting samples the carboniferous donets coals yielded more bitumen and hydrocarbons than cretaceous sabinas coal during artificial maturation low proportions of solid bitumen r r and 1 5 r r during confined pyrolysis of coals two solid bitumen groups have been identified which correspond to distinct phases of neo formation the drop in the solid bitumen content at higher ranks indicates that it contributes to generation of gas during experimental simulation moreover their morphology and porosity change with the level of maturity the porosity of the vitrinite matrix increases as well as the pore size with increasing maturity a relationship has been observed between the porosity and the weight loss the higher pore content of carboniferous donets coals is correlated with a higher generation of gas compared to cretaceous sabinas coal

germanium geochemistry and mineralogy abstract germanium is enriched in the following geologic environments 1 1 iron meteorites and terrestrial iron nickel 2 2 sulfide ore deposits particularly those hosted by sedimentary rocks 3 3 iron oxide deposits 4 4 oxidized zones of ge bearing sulfide deposits 5 5 pegmatites greisens and skarns and 6 6 coal and lignitized wood in silicate melts ge is highly siderophile in the presence of native iron nickel otherwise it is highly lithophile among silicate minerals ge is concentrated in those having less polymerized silicate tetrahedra such as olivine and topaz in deposits formed from hydrothermal solutions ge tends to be enriched mostly in either sulfides or in fluorine bearing phases it is thus concentrated both in some hydrothermal sulfide deposits and in pegmatites greisens and skarns in sulfide deposits that formed from solutions having low to moderate sulfur activity ge is concentrated in sphalerite in amounts up to 3000 ppm sulfide deposits that formed from solutions having higher sulfur activity allowed ge to either form its own sulfides particularly with cu or to substitute for as sn or other metals in sulfosalts the ge in hydrothermal fluids probably derives from enrichment during the fractional crystallization of igneous fluids or is due to the incorporation of ge from the country rocks particularly from those containing organic material germanium bonds to lignin derivative organic compounds that are found in peat and lignite accounting for its common concentration in coals and related organic material germanium is precipitated from water together with iron hydroxide accounting for its concentration in some sedimentary and supergene iron oxide deposits it also is able to substitute for fe in magnetite in a variety of geologic environments in the oxidized zone of ge bearing sulfide deposits ge is concentrated in oxides hydroxides and hydroxy sulfates sometimes forming its own minerals it is particularly enriched in some iron and manganese bearing oxides and hydroxides including goethite up to 5300 ppm and hematite up to 7000 ppm

pedogenic zonation in the well drained soils of the arctic regions abstract pedogenic zonation in the soils of the polar regions is a result of gradients in environmental factors and attendant chemical processes along a latitudinal transect it is best manifested at well drained sites and by soils developed on predominantly silicate rocks selected sites in arctic alaska in the canadian arctic greenland and svalbard adequately fulfill these prerequisites the processes of podzolization decarbonization carbonization pervection and salinization as models of arctic pedogenesis demonstrate that processes occurring in the temperate region also operate in the far north brunification melanization and oxidation are recognized for the first time as current geochemical and pedogenic mechanisms of the arctic region traditional genetic soil names have been retained because they represent a closer relationship to pedogenic processes than the more modern nomenclature the identification the chemical behavior the strength abundance and mobility of the proton donors and conjugate bases are keys to the genesis of soils and the distinction of contrasting soil processes this new approach to the understanding of arctic pedogenesis can be better fulfilled by collecting analyzing and interpreting soil solution obtained in situ

crustal architecture of the donets basin tectonic implications for diamond and mercury antimony mineralization abstract kimberlite like rocks and minor diamond finds are reported in the precambrian ukrainian shield south of the donets basin prolific mercury antimony mineralization occurs in carboniferous quartz arenites within the basin the tectonic setting is examined on the basis of recent data compilations and ongoing research in the ukraine and voronezh shield areas and the pripyat dnieper donets palaeorift in the donets region a straightforward analogy of any diamond district with the archangelsk province is not likely in the absence of a proterozoic shear comparable with the white sea belomorian mobile belt a deep reaching nnw striking lithosphere lineament is identified here as the kharkov donetsk lineament it transects the rift between the donets and dnieper basins the structures involved in this lineament have controlled palaeozoic sedimentation and the extent of late permian inversion of the donets basin during the inversion the lineament and associated deep reaching longitudinal structures provided pathways for the migration of mineralizing fluids from deep levels in the lower crust and upper mantle the intersection in the kharkov area of this lineament with a northeasterly striking lithosphere root should focus diamond exploration towards the northern shoulders of the rift the extreme attenuation of the crust beneath the donets basin relative to the western basins of the rift is associated with crustal detachment and subsidence during and possibly after inversion concomitant with emplacement of asthenospheric materials at higher levels together with the continued subsidence in the western donets basin during the late permian inversion this invokes a tectonic setting for the hg sb mineralization not unlike the orogenic collapse associated settings of hg sb deposits in western europe further investigation of the geodynamics of the donets basin would benefit from deep reflection seismics petrogenetic studies of magmatic products and their xenoliths and satellite remote sensing analysis

bituminous coal seams from underground mines in the zonguldak basin nw turkey insights from mineralogy coal petrography rock eval pyrolysis and meso and microporosity abstract the zonguldak basin contains the main bituminous coal reserves of turkey ca 1 4 gt and several coal seams are mined in underground coal mines within the basin this study focuses on coal petrography mineralogy rock eval pyrolysis and the meso and microporosity characteristics of the coal samples collected from several late carboniferous pennsylvanian bituminous coal seams in the basin forty channel samples were collected from various coal seams in underground mines at the armutcuk zonguldak and amasra coalfields in the zonguldak basin the studied coal samples have low total moisture contents avg 2 3 on as received basis low total s contents avg 0 5 on dry basis and relatively high ash yields avg 21 2 on dry basis the random vitrinite reflectance values 0 69 1 21 and gross calorific values avg 33 0 mj kg on dry ash free basis indicate that the coal samples are of high volatile c bituminous to medium volatile bituminous coal minerals identified by xrd in bulk coal samples are clay minerals mainly kaolinite and rarely illite and chlorite quartz and carbonates calcite dolomite and siderite in a few samples pyrite and feldspar were also identified the sem edx analyses performed on the carbon coated polished blocks imply that the carbonate minerals are mainly epigenetic whereas the silicate minerals are generally syngenetic in origin the results of low pressure n2 adsorption analysis indicate that the bet surface areas 1 1 5 5 m2 g and mesopore volumes 0 003 0 011 cm3 g vary within a wide range the results of the low pressure co2 adsorption analyses show that micropores are abundant in the coal samples however the bet surface areas 10 41 78 11 m2 g and micropore volumes 0 010 0 049 cm3 g vary widely among the three coal mines and different coal seams our results suggest that variations in the mesopore characteristics are mainly controlled by mineral matter while microporosity is controlled by a combination of organic matter maceral compositions and coal rank of the studied coal seams

variable gas content saturation and accumulation characteristics of weibei coalbed methane pilot production field in the southeastern ordos basin china using diverse geologic and geophysical data from recent exploration and development and experimental results of analysis of gas content gas capacity and gas composition this article discusses how geologic structural and hydrological factors determine the heterogeneous distribution of gas in the weibei coalbed methane cbm field the coal rank of the pennsylvanian no 5 coal seam is mainly low volatile bituminous and semianthracite the total gas content is 2 69 to 16 15 m3 t 95 00 570 33 scf t and gas saturation is 26 0 to 93 2 burial coalification followed by tectonically driven hydrothermal activity controls not only thermal maturity but also the quality and quantity of thermogenic gas generated from the coal gas composition indicates that the cbm is dry and of dominantly thermogenic origin the thermogenic gases have been altered by fractionation that may be related to subsurface water movement in the southern part of the study area three gas accumulation models are identified 1 gas diffusion and long distance migration of thermogenic gases to no flow boundaries for sorption and minor conventional trapping 2 hydrodynamic trapping of gas in structural lows and 3 gas loss by hydrodynamic flushing the first two models are applicable for the formation of two cbm enrichment areas in blocks b3 and b4 whereas the last model explains extremely low gas content and gas saturation in block b5 the variable gas content saturation and accumulation characteristics are mainly controlled by these gas accumulation models

on pollution of the biosphere in industrial areas the example of the donets coal basin abstract the distribution of heavy metals nitrates and other elements and compounds was studied in the donets basin biosphere the neomineralization processes in burning coal waste heaps were investigated more than 10 minerals were found for the first time in the donets basin the most frequently occurring are native sulphur and ammonium chloride in the process of geochemical mapping 30 000 soil samples were collected and analyzed the soil content of hg as pb zn cd and other elements was determined these concentrations often exceed the permissible level of concentration plc the soil mercury content is high in 90 of the donetsk city territory in some places it is 7 5 9 0 mg kg several times higher than the plc a high mercury concentration up to 19 mg kg was found in the soils of the central donbas area where the large coke chemical mercury and metallurgical plants are situated the air mercury content is about 25 30 pg l 1 pg 10 12 g in donetsk city and it is 300 1000 pg l or more near the nikitovsky mercury plant the background level is 1 6 1 8 pg l geochemical anomalies of arsenic mercury nitrates and other toxic elements and compounds were detected in 6000 donbas subsurface water samples near donetsk the arsenic content is up to 24 times and the mercury content is up to 3 10 times higher than the plc nitrate pollution of the donbas subsurface water covers 80 of the territory the nitrate content is as high as 500 1000 mg l and more plc is 45 mg l the sources of biosphere pollution by heavy metals and nitrates are coal waste heaps coal mines coke chemical plants metallurgical plants and other enterprises toxic pollution of the donbas biosphere negatively influences human health further systematic investigations of the donbas biosphere need to be conducted involving cooperation between scientists of different countries under joint programs

coal petrography mineralogy elemental compositions and palaeoenvironmental interpretation of late carboniferous coal seams in three wells from the kozlu coalfield zonguldak basin nw turkey abstract a number of coal seams of late carboniferous age in the coal bearing karadon kozlu and alacaagzi formations have been mined in several deep underground mines in the zonguldak basin nw turkey for this study a total of 154 coal core samples were collected from three research wells that were drilled in the tectonically complex settings of the kozlu coalfield all the coal samples were studied by means of coal petrography mineralogy and geochemistry special attention was given to the compositions and origins of fracture cleat filling minerals that were identified by sem edx on polished blocks the coal seams investigated are of bituminous rank they are characterized by low total sulphur contents 1 0 on dry basis and high gross calorific values 22 5 40 2 mj kg on dry ash free basis whereas ash yields and volatile matter contents are variable x ray powder diffraction data indicate that the mineralogical compositions of the studied coal seams are rather similar and clay minerals along with quartz and carbonate minerals were identified in almost all seams the statistical evaluations and sem data show that some elements such as mg ti zr nb and th are generally affiliated with silicate minerals whereas elements like cu zn mo and pb are mainly associated with sulphide minerals the silicate minerals are generally detrital and the majority of carbonate minerals are of epigenetic origin the epigenetic carbonate and sulphide minerals suggest that circulated solutions within coal seams were mainly derived from ca2 rich solutions leached from overlying formations such as cretaceous aged zonguldak formations and from hydrothermal solutions that likely were derived from andesitic dykes within the basin the regional tectonic activities during coalification seem to have deformed coal bearing formations and therefore intra basinal solutions could have penetrated into the studied coal seams the epigenetic mineralisation also resulted in elemental enrichments and elevated ash yields total sulphur and volatile matter contents in some coal seams thus deformation during coalification controlled some coal quality parameters in the studied wells the coal facies diagrams suggest that palaeomires mostly accumulated under limno telmatic conditions whereas a telmatic environment was more common in palaeomires of the kozlu formation coal petrography suggests that peat forming vegetation and water tables in palaeomires were changeable during the late carboniferous

sequence stratigraphy and correlation of late carboniferous and permian in the cis europe tethyan area north africa arabia china gondwanaland and the usa abstract sequence stratigraphy was used to correlate the depositional chronology during permo carboniferous time in various sedimentary basins of gondwanaland western europe eastern europe tethyan area north africa arabia china and north america during late carboniferous and permian eleven second order sequences sos were recognised throughout the whole area the sequence si is serpukhovian pp namurian a pp and chesterian the sequence sii is serpukhovian pp bashkirian pp namurian a pp b c westphalian a b pp and morrowan the sequence siii is late bashkirian moscovian westphalian b pp c d and atokan desmoinesian the sequence siv is kasimovian early stephanian and missourian the sequence sv is gzhelian orenburgian late stephanian and virgilian the sequence svi is asselian autunian and nealian the sequences svii ix are saxonian sakmarian artinskian kungurian and leonardian hessian cathedralian the sequences sx xi are guadalupian and lopingian depending on the regional setting different relationships exist between marine transgression and the respective effects of tectonics and of sea level changes in western europe effects of the glacial processes in gondwanaland are partly balanced by the late compression in the hercynian belt during moscovian eastern europe tethyan area north africa china and north america show a good correlation between glacial ice melting processes in gondwanaland and the intensity of the transgression which is increased by the westward progradation of the orogeny in urals and appalachians in arabia tunisia and tethyan area the impact of the neotethys opening is obvious from the artinskian and mainly during the late permian

the effects of magma intrusion on localized stress distribution and its implications for coal mine outburst hazards abstract magma intrusions into coal seams are common throughout the world the high temperatures and pressures induced by magma intrusion can alter the properties of coal including its rank mechanical properties cleat and pore structures and adsorption desorption behaviors because the thermal properties of magma intrusions also affect localized in situ stress distributions both the alteration of coal properties and changes in stress distribution can directly influence coal seam gas outburst disasters this phenomenon was recently observed and confirmed by several outbursts in the haizi coal mines of huaibei china in this paper the processes and mechanisms of this magma intrusion are comprehensively analyzed based on an integrated data set including previously published geological data in house laboratory tests and field observations the results demonstrate that there is an intrinsic relationship between the intrusive sill and the subsequent in situ stress distribution these data suggest that the magma intrusion in the haizi coalfield originated as a crust mantle type controlled by magmatic underplating later transported mantle derived magma successively along the tanlu fracture belt the subei fault and the daliujia fault and finally intruded into the coalfield as a thick sill by comparing the lithologies of the coal seam roof and floor as well as the distances between key coal seams no 3 and no 7 it was discovered that the magma intrusion that entered the no 5 coal seam was also associated with erosional effects the squeezing that occurred during this intrusion changed the in situ stress distribution within the region which increased along with the increasing thickness of the overlying sill therefore the increased in situ stress also caused an increase in the outburst risk of the underlying coal seam a conclusion that was verified by measuring the quantity of drilling cuttings on working faces as well as onsite outburst events

variscan cycling of gold into a global coal reservoir this project is in support of the nerc sos security of supply of critical elements programme under grant ne m010953 1 j johnston and j bowie provided skilled technical help the manuscript benefitted from incisive reviews by n moles y wu carmine and an anonymous reviewer whose advice is much appreciated

paleostress field reconstruction and revised tectonic history of the donbas fold and thrust belt ukraine and russia 1 in the wnw ese donbas fold belt df inversion of 3500 microtectonic data collected at 135 sites in proterozoic devonian carboniferous and cretaceous competent rocks allowed reconstruction of 123 local stress states accordingly four successive paleostress fields reveal the tectonic evolution of the df at the numerous sites that have been affected by polyphase tectonics the chronology between local paleostress states also paleostress fields was established using classical criteria crosscutting striae pre or post folding stress states stratigraphic control the oldest event is an extensional stress field with nne ssw 3 it corresponds to the rifting phases that generated the basin in devonian times and its early visean reactivation later the df was affected by a transtension with nw se 3 characterizing early permian tectonism including the development of the main anticline of the df and the pronounced uplift of its southern margin and ukrainian shield two paleostress fields characterize the cretaceous paleocene inversion of the df which was accompanied by folding and thrusting both are compressional in type but differ by the trend of 1 which was first nw se and subsequently n s the discrete paleostress history of the df allows a revised interpretation of its tectonic evolution with significant implications for understanding the geodynamic evolution of the southern margin of the east european craton

chemical weathering in the foreland of a retreating glacier chemical denudation rates and strontium isotope ratios in streams vary substantially and systematically in the foreland of the retreating bench glacier in south central alaska to study weathering of young glacier sediments we sampled 12 streams draining a chronosequence of till and moraine soils derived from cretaceous metagraywacke metapelite bedrock both sediment age and vegetation cover increase with distance from the glacier cation denudation rates decline with increasing distance from the glacier whereas silica denudation rates increase carbonate dissolution and sulfide oxidation account for roughly 90 of the solute flux from the youngest sediments biotite alteration accounts for 5 11 of the solute flux its peak contribution is found in the glacier outlet stream silicate weathering is the dominant reaction only in the oldest sediments in a laboratory dissolution experiment using fresh glacial sediment carbonate dissolution dominated the solute flux during the first 700 hours paralleling the behavior of young sediments in the field in contrast to trends in the field the silica flux did not increase after the carbonate was exhausted from the reactor a possible reason for this difference is that establishment of vegetation causes an increase in silicate weathering the 87sr 86sr ratio in the glacier outlet stream is greater than that in proglacial streams and in bulk rock due to a greater contribution of biotite weathering in the outlet than in proglacial streams strontium isotope ratios decline with sediment exposure age in the proglacial streams and are consistent with a carbonate source because the dominant weathering reactions in the young sediments are of carbonate and sulfide rather than silicate minerals weathering at the glacier margin is not an important long term sink for atmospheric co2

petrographic and geochemical effects of sill intrusions on coal and their implications for gas outbursts in the wolonghu mine huaibei coalfield china abstract since the early 1980s fifteen outbursts have occurred in the huaibei coalfield of china these outbursts were reported to be associated with sills to study the effect of sill intrusions on coal seam and their relationship to methane outbursts eleven samples from the no 10 coal seam were taken from the wolonghu mine at various distances from a diorite sill comparisons were made between unaltered and heat affected coals using petrographic and chemical data micropore characteristics adsorption properties of coal and gas outburst indexes from field approaching the intrusion vitrinite reflectance levels increased from 2 74 to 5 03 and the thermal aureole of the sill 60 m from the sill boundary to sample 9 three zones along this gradient were identified as corresponding to 1 thermal evolution zone no 1 0 5 m from sill 2 thermal evolution zone no 2 5 60 m from sill and 3 unaltered zone the methane adsorption capacity of coal samples in the thermal evolution zone no 2 was generally higher than in the two other zones and the unaltered zone higher than the thermal evolution zone no 1 it is concluded that the contact metamorphism decreased the adsorption capacity of coal and the thermal evolution of sill increased it the trap effect of sill combined with the mudstone and siltstone roof and floor of the no 10 coal seam provided a seal for the formation of a gas pocket abnormally high formation pressures at the no 10 coal seam led to two outbursts

glacial interglacial variability of atmospheric co2 due to changing continental silicate rock weathering a model study an 11 box model of the oceanic carbon cycle including sedimentary processes is used to explore the role chemical weathering of continental silicate rocks might play in driving atmospheric co2 levels on glacial interglacial timescales histories for the consumption of co2 by silicate rock weathering processes are derived from the marine ge si record taking the major uncertainties in the knowledge of the ge and si cycles into account several histories for the evolution of the riverine dissolved silica fluxes are calculated from this record the investigation of the systematics between riverine dissolved silica and bicarbonate fluxes under different weathering regimes leads us to the tentative conclusion that although there is no correlation between dissolved silica and total bicarbonate concentrations in the major rivers there may exist a negative correlation between weathering intensity and the ratio of dissolved silica to bicarbonate derived from silicate weathering alone with this correlation as a working hypothesis it is possible to interpret the dissolved silica fluxes in terms of equivalent co2 consumption rates the calculated histories indicate that glacial rates of co2 consumption by chemical silicate rock weathering could have been twice and possibly up to 3 5 times as high as they are today when used to force the carbon cycle model they are responsible for glacial interglacial pco2 variations in the atmosphere of typically 50 60 ppm and up to 95 110 ppm these variations are superimposed to a basic oscillation of 60 ppm generated by the model mainly in response to coral reef buildup and erosion processes the total pco2 signal has an amplitude of about 80 90 ppm and up to 125 135 ppm although these large amplitudes indicate that silicate weathering processes should be taken into account when studying glacial interglacial changes of co2 in the atmosphere it also raises new problems such as too high co2 levels during the period from 110 70 kyr b p requiring further study

river fluxes of dissolved silica to the ocean were higher during glacials ge si in diatoms rivers and oceans two centric marine diatom species thalassiosira oceanica and thalassiosira antarctica were grown in batch cultures to determine the incorporation of germanium ge and silicon si into siliceous shells opal the results were modeled as ge si isotope fractionation during exponential growth diatoms take up and incorporate ge si from solution without major discrimination against ge during stationary phase growth near silica limitation the antarctic species t antarctica discriminates slightly against ge but integrated ge si opal produced over the latter portion of the growth cycle is indistinguishable from the initial solution ratio these results confirm experiments using radioactive 68ge that showed absence of fractionation during diatom silica uptake azam and volcani 1981 in contrast to two box ocean models that invoke 50 ge discrimination by diatoms to explain the observed excess surface ocean germanium concentration murnane and stallard 1988 froelich et al 1989 and late pleistocene ocean sediment ge si opal records mortlock et al 1991 runs of a 10 box ocean ge and si model pandora with 50 discrimination reproduce the excess surface ocean ge but introduces curvature into the deep ocean ge versus si relationship that is not observed in the oceans thus 50 fractionation is not supported by either cultures or models if diatoms do not fractionate ge si then late pleistocene ge si opal variations in piston cores are caused not by changes in local biosiliceous production and silica utilization mortlock et al 1991 but rather by whole ocean changes in ge si seawater the marine ge si opal record of the last 450 kyr can be modeled as transient oceanic responses to instantaneous continental climate transitions consistent with the chemical weathering model of murnane and stallard 1990 glacial periods are characterized by lower continental weathering intensity lower ge si riv and two fold higher dissolved silica river fluxes marine ge si opal records thus contain a history of ocean silica chemistry that reflect rapid global changes in continental weathering

chemical weathering in glacial environments do glaciers enhance or inhibit chemical weathering rates relative to other environments the importance of glaciers in the global carbon cycle and climate change hinges on the answer we show that catchments occupied by active alpine glaciers yield cation denudation rates greater than the global mean rate but do not exceed rates in nonglacial catchments with similar water discharge silica denudation rates are distinctly lower in glacier covered catchments than in their nonglacial counterparts because sediment yields are high from glaciers this suggests that water flux rather than physical erosion exerts the primary control on chemical erosion by glaciers potassium and calcium concentrations are high relative to other cations in glacial water probably due to dissolution of soluble trace phases such as carbonates exposed by comminution and cation leaching from biotite preferential weathering of biotite may result in higher 87 sr 86 sr in glacial runoff than expected from whole rock compositions thus although glaciers do not influence total chemical denudation rates at a given runoff they may yield compositionally distinctive chemical fluxes to the oceans disruption of mineral lattices by grinding increases dissolution rates this and high surface area should make glacial sediments exceptionally weatherable weathering of glacial erosion products in environments beyond the glacier margin deserves attention because it may figure prominently in global chemical cycles

low temperature thermal evolution of the azov massif ukrainian shield ukraine implications for interpreting u th he and fission track ages from cratons abstract the low temperature thermal evolution of the azov massif eastern part of the ukrainian shield ukraine is investigated by combined zircon fission track zft apatite fission track aft and apatite u th he ahe thermochronology the data help to better understand the geodynamic evolution of the azov massif and the adjacent intra cratonic rift basin dniepr donets basin as follows zft data reveal that the precambrian crystalline basement of the azov massif was heated to temperatures close to 240 c during the late palaeozoic the heating event is interpreted in terms of burial of the basement beneath a several kilometres thick pile of devonian and carboniferous sedimentary deposits of the adjacent dniepr donets basin during permo triassic times large parts of the basement were affected by a thermal event related to mantle upwelling associated magmatic activity and increased heat flow in the adjacent rift the major part of the basement cooled to near surface conditions in the early to middle triassic and since then was thermally stable as suggested by aft and ahe data further aft data confirm late triassic magmatic activity in the azov massif which however did not influence regional thermal pattern the northern part of the basement and its sedimentary cover record a cooling event in the jurassic which was probably related to erosion however although ar ar data of jurassic magmatic activity in the donbas foldbelt are about 20 my younger than the aft data thermal relaxation after elevated heat flow associated with this magmatic event cannot be completely ruled out our results reveal apparent inconsistencies between aft and ahe data the ahe ages corrected for alpha ejection according to the standard procedure farley k a wolf r a silver l t 1996 the effect of long alpha stopping distances on u th he ages geochim cosmochim acta 60 21 4223 4229 farley k a 2002 u th he dating techniques calibrations and applications mineral soc am rev mineral geochem 47 819 844 are older than corresponding aft ages in order to test the relevance of alpha ejection correction mechanical abrasion of several apatite grains was applied we found that in case of relatively slow cooling alpha ejection correction of raw u th he ages leads to erroneously high ages this shows that alpha ejection correction should be used with caution we propose that this correction should only be applied to samples with a fast cooling history whereas it should not be applied to slowly cooled samples and to samples whose thermal history is not constrained by other means

origin and significance of isotope shifts in pennsylvanian carbonates asturias nw spain abstract the primary variability of the composition and properties of seawater is much greater in the shallow coastal zones than in the main body of ocean water an inadequate understanding of this variability as well as different diagenetic environments severely limit the interpretation of the stable isotope record of shoalwater carbonates in order to investigate this primary and diagenetic variability along a bashkirian moscovian platform to basin transect 13c and 18o analyses have been performed on more than 1000 matrix micrite carbonate cement and brachiopod shell samples in isotope analysis these different carbonate materials tend to complement each other inasmuch as they have different advantages and shortcomings the resulting data reveal spatial trends in 13c and 18o signatures from platform top lower values to basin higher values in the case of 13c from pristine brachiopods this trend can be explained by the long residence time aging of platform top water masses in the case of brachiopod 18o this variance is interpreted to reflect temperature differences between warm surface and colder bottom water separated by a permanent thermocline at about 150 to 200 m beneath the shelf break micrite and marine cement isotopic values from the platform interior were reset lowered during pervasive early meteoric diagenesis in contrast micrite and marine cement isotopic values from the outer platform slope and basin show higher values close to the assumed pennsylvanian seawater isotopic composition this implies that isotopic data from shoalwater carbonates including pristine brachiopod shells might not necessarily reflect paleoceanographic trends of the open ocean water masses because of changes in coastal water mass isotope signature and interaction with early meteoric fluids

evolution of the southern margin of the donbas ukraine from devonian to early carboniferous times a devonian early carboniferous succession comprising thick clastic and carbonate sediments with interbedded volcanics was examined along the southern margin of the donbas fold belt ukraine following initial rifting and subsidence a continental fluvial lacustrine succession was established this first phase of synrift activity eifelian was accompanied by the extrusion of basalts in late givetian early famennian times half graben development was pronounced and a series of e w trending half grabens were formed along with coeval volcanic activity subsequent basin subsidence led to the establishment of a broad marine carbonate platform across the region late famennian tournaisian early visean renewed uplift led to partial exposure and karstification of the platform this was accompanied by trachyte intrusion and extrusion the overlying chert rich unit was probably deposited under lacustrine conditions although a shelf environment has also been suggested renewed tectonic activity along the main basin bounding fault resulted in the synsedimentary deformation of this unit

black shales in ukraine a review abstract as a result of a long lasting and complex geological history organic matter rich fine grained rocks black shales with widely varying ages can be found on ukrainian territory several of them are proven hydrocarbon source rocks and may hold a significant shale gas potential thick silurian black shales accumulated along the western margin of the east european craton in a foreland type basin by analogy with coeval organic matter rich rocks in poland high toc contents and gas window maturity can be expected however to date information on organic richness is largely missing and maturity patterns remain to be refined visean black shales with toc contents as high as 8 and a type iii ii kerogen accumulated along the axis of the dniepr donets rift basin ddb they are the likely source for conventional oil and gas oil prone serpukhovian black shales accumulated in the shallow northwestern part of the ddb similar black shales probably may be present in the lviv volyn basin western ukraine middle jurassic black shales up to 500 m thick occur beneath the carpathian foredeep they are the likely source for some heavy oil deposits toc contents up to 12 type ii have been recorded but additional investigations are needed to study the vertical and lateral variability of organic matter richness and maturity lower cretaceous black shales with a type iii ii kerogen toc 2 are widespread at the base of the carpathian flysch nappes but oligocene black shales menilite fm rich in organic matter 4 8 toc and containing a type ii kerogen are the main source rock for oil in the carpathians their thermal maturity increases from the external to the internal nappes oligocene black shales are also present in crimea maykop fm these rocks typically contain high toc contents but data from ukraine are missing

factors controlling shale microstructure and porosity a case study on upper visean rudov beds from the ukrainian dneiper donets basin the present contribution aims for a characterization of microstructure and pore space distribution of upper visean rudov beds considered the main source rock for conventional oil deposits in the ukrainian dneiper donets basin and a prospect for unconventional hydrocarbon production in recent years broad ion beam scanning electron microscopy sem mapping revealed a remarkably heterogeneous microstructure controlled by diagenetic precipitates fe mg carbonates albite formation of these precipitates is likely triggered by organic matter decomposition and represents an important influencing factor for overall porosity and permeability furthermore shale diagenesis also influences mechanical properties as suggested by nanoindentation tests the sem visible organic matter porosity is restricted to solid bitumen although pores less than 2 3 nm in vitrinites of overmature samples are indicated by focused ion beam sem results they cannot be resolved clearly by this method pore generation in solid bitumen that likely formed in situ in primary amorphous organic matter already starts at the early oil window in samples from the basinal oil prone organofacies whereas most porous solid bitumen at peak oil maturity was interpreted as relicts of primary oil migration representing an earlier oil phase that predominantly accumulated in quartz rich layers and became nanoporous during secondary cracking in the terrestrially dominated transitional to marginal organofacies pore generation in pyrobitumen resulting from gas generation occurs significantly later and is less intense formation of authigenic clay and carbonate minerals within pyrobitumen is likely related to organic acids formed during bitumen decomposition and implies the presence of an aqueous phase even in pores that are apparently filled exclusively with solid bitumen