calcretes at sequence boundaries in upper carboniferous cyclothems of the sydney basin atlantic canada abstract nodular and associated groundwater calcretes in coal bearing cyclothems of the sydney basin mark the boundary between underlying marginal marine and overlying alluvial deposits they are inferred to represent lowstand surfaces sequence boundaries the host sediments include both sand siltstones and palustrine limestones microfabrics of calcretes with detrital hosts show evidence of replacement displacement and shrinkage alpha fabrics suggesting that the calcretes formed under relatively arid conditions in contrast microfabrics of nodular calcretes with limestone hosts exhibit predominantly beta fabrics with root induced brecciation and subordinate shrinkage fabrics the calcretes and host limestones are inferred to have formed in topographic lows thick alluvial sediments with red calcic vertisols overlie the calcretes and formed within the transgressive systems tract under conditions of abundant sediment supply coals and associated hydromorphic palaeosols lie near the transgressive maximum and in the highstand systems tract the presence of calcareous palaeosols on lowstand surfaces suggests that the lowstands were times of relative climatic aridity

use of ground probing radar and resistivity surveys for archaeological investigations in japan geophysical methods are normally used to estimate the distribution of cultural relics before digging objects of archaeological interest are usually located within a few meters of the surface therefore geophysical methods suitable for archaeological exploration are those which provide high resolution at shallow depths the most commonly used geophysical methods are ground probing radar resistivity and magnetometry of these methods we used mainly ground probing radar and resistivity surveys in archaeological investigations at four sites three of the sites were in gumma prefecture japan they were covered with volcanic deposits loam or pumice using ground probing radar we were able to locate ancient dwellings burial mounds and a distribution of archaeologically significant culture layers at the other site in nara prefecture we located part of the remains of an ancient city in this investigation the resistivity method and ground probing radar were combined to determine the loc

fast monostatic gpr modeling we propose the exploding reflector method to simulate a monostatic survey with a single simulation the exploding reflector used in seismic modeling is adapted for ground penetrating radar gpr modeling by using the analogy between acoustic and electromagnetic waves the method can be used with ray tracing to obtain the location of the interfaces and estimate the properties of the medium on the basis of the traveltimes and reflection amplitudes in particular these can provide a better estimation of the conductivity and geometrical details the modeling methodology is complemented with the use of the plane wave method the technique is illustrated with gpr data from an excavated tomb of the nineteenth century

vegetation zones and diagnostic pollen profiles of a coastal peat swamp bocas del toro panama abstract a survey of the dominant vegetative cover of a large domed coastal swamp near changuinola in the province of bocas del toro panama has been undertaken as an initial step in reconstructing the holocene history of peat accumulation on this coast seven phasic communities of peat forming vegetation are defined and mapped 1 rhizophora mangle mangrove swamp 2 mixed back mangrove swamp 3 raphia taedigera palm swamp 4 mixed forest swamp 5 campnosperma panamensis forest swamp 6 sawgrass stunted forest swamp 7 myrica cyrilla bog plain pollen extracted from surface peat samples and collected from dominant vegetation at representative sites is used to prepare a pollen profile of each phasic community these profiles are then compared to pollen distribution in 2 peat cores one from the deep central part of the deposit and the second from a site near the marine margin in order to construct a history by floral succession of the 4000 year evolution of the deposit the changuinola mire originated as freshwater palm and hardwood forest swamps that developed in close proximity to both the changuinola river mouth probably behind a barrier bar and freshwater lagoon system adjacent to a low energy mangrove dominated bay the early swamp was likely drained to the southeast by brackish blackwater creeks much as it is today and formerly extended considerably farther in the direction of almirante bay the palm swamp was succeeded by hardwood forest swamp dominated by a very limited number of specialized species only one of which campnosperma panamensis is prone to forming monospecific stands increasing accumulation of woody peat promoted by the everwet climate impeded drainage of the mire leading to doming increased oligotrophy and establishment of bog plain conditions in a manner similar to that described by the anderson model of succession in the coastal swamps of malaysia and indonesia development of the changuinola mire did not require the initial mangrove phase which is common to the peat swamps of southeast asia as the palm raphia taedigera is able to colonise and institute peat accumulation in a variety of freshwater and brackish environments

cyclothem digital correlation and biostratigraphy across the global moscovian kasimovian gzhelian stage boundary interval middle upper pennsylvanian in north america and eastern europe the long standing difficulty of correlating pennsylvanian strata among provincial faunal regions is resolved by effecting digital correlation of major glacial eustatic cyclothems that represent high stands when certain species achieved more global distribution than usual in the late moscovian early gzhelian late desmoinesian early virgilian succession in the midcontinent united states several major cyclothems are correlated by both conodont species in common and cyclothem scale with cyclothems in russia moscow basin and ukraine donets basin and the remaining cyclothems fit into the framework by position and scale in this way the suggested event marker for the global kasimovian gzhelian stage boundary first appearance of idiognathodus simulator is supported while possible event markers for the moscovian kasimovian boundary await further evaluation

stratigraphic model for glacial eustatic pennsylvanian cyclothems in highstand nearshore detrital regimes lower distal positions on gently sloping shelves ramps affected by pennsylvanian glacial eustatic sea level fluctuation display classic marine transgressive regressive cyclothems which are separated by exposure surfaces or by shallow marine to thin terrestrial beds deposited at lowstand in contrast higher shelf proximal positions display marginal marine units and coastal plain coal beds deposited at marine highstand and separated by thicker terrestrial units both marine and terrestrial strata deposited in high shelf positions underwent significant fluvial incision and valley formation during long stands of lower sea level resulting in discontinuous erosional remnants and subsequent localized terrestrial deposition on irregular leached and eroded surfaces examples from the appalachian illinois and sydney basins display features such as erosional disconformities with rotated slumps buried hilltops preserving erosional remnants of marine units colluvially reduced landscape relief and buried

early mississippian sandy siltstones preserve rare vertebrate fossils in seasonal flooding episodes this study is a contribution to the tw eed project tetrapod world early evolution and diversification a major research programme investigating the rebuilding of carboniferous ecosystems following a mass extinction at the end of the devonian smithson et al 2012 this study was funded by nerc consortium grant the mid palaeozoic biotic crisis setting the trajectory of tetrapod evolution led by professor jenny clack university museum of zoology cambridge and involving the universities of cambridge ne j022713 1 leicester ne j020729 1 southampton ne j021091 1 the british geological survey ne j021067 1 and the national museum of scotland

a depositional model for the taylor coal bed martin and johnson counties eastern kentucky abstract this study investigated the taylor coal bed in johnson and martin counties eastern kentucky using field and petrographic techniques to develop a depositional model of the coal bed petrography and chemistry of the coal bed were examined multiple benches of the taylor coal bed were correlated over a 10 km distance three sites were studied in detail the coal at the western and eastern sites were relatively thin and split by thick clastic partings the coal at the central site was the thickest and unsplit two major clastic partings are included in the coal bed each represents a separate and distinct fluvial splay the taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby structurally controlled fluvial systems doming is unlikely due to the petrographic and chemical trends which are inconsistent with modern indonesian models the depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the taylor coal bed in this area

intensive surveys of the azores front 2 inferring the geostrophic and vertical velocity fields the geostrophic and vertical velocity fields are inferred using density and horizontal velocity data from three seasoar acoustic doppler current profiler surveys of the azores front the analysis is a two step procedure consisting of 1 objective analyses to reflect the observed length scales and 2 dynamical adjustments so that the density field is statically stable and the velocity field is in geostrophic balance the vertical velocity is inferred using a version of the quasi geostrophic omega equation in which the stratification is allowed to vary in the horizontal the resulting vertical velocity peaks at 2 10 4 m s 1 at 200 300 m there is a tendency for the denser water to the north of the front to be downwelled while the warmer water to the south is upwelled the implied heat flux exceeds 10 w m 2 near 100 m depth so the upper 100 m is warmed while the lower water column is cooled tending to stratify the upper ocean ageostrophic horizontal flow is toward the dense side of the front at the surface the dominant terms in the density balance are time rate of change and horizontal advection the inferred circulation cells may be an important mechanism of subduction in the upper ocean

the pedogenic formation of coal balls by co2 degassing through the rootlets of arborescent lycopsids coal balls are calcium carbonate accumulations that permineralized peat in paleotropical permo carboniferous 320 250 ma mires the formation of coal balls has been debated for over a century yet a widely applicable model is lacking two observations have been particularly challenging to explain 1 the narrow temporal occurrence of coal balls and 2 their typical elemental high mg and isotopic low 18o composition that paradoxically indicate marine and freshwater origins respectively we evaluate a new model in which coal balls formed as co2 escaped from the peat by diffusion through unusual air filled spaces in the rootlets of lycopsid trees critically these trees were very common in paleotropical mires and their evolutionary range matches the temporal range of coal balls the episodic delivery of seawater and marine carbonate sediment to coastal mires is the first step in our model although other pathways for the delivery of divalent cations are permissible subsequent dilution by freshwater and dissolution of these carbonates at the elevated co2 of the mire subsurface is followed by the transport of co2 through the rootlet airspaces and into the overlying water and atmosphere which drives carbonate mineral precipitation in the sediment we show that dilution by freshwater because it minimally affects mg ca ratios can result in relatively low pore water 18o values while allowing high mg calcite formation this model thus explains the restriction of coal balls to the permo carboniferous and resolves the discrepancy between elemental and isotopic compositions of coal ball carbonate minerals furthermore we show with a 3d reactive transport model that co2 could escape rapidly enough through the rootlets to fill 25 percent of the peat pore spaces with calcite before substantial burial top decimeter of peat explaining the exceptional preservation of coal swamp flora therefore we suggest that coal balls are pedogenic in origin and that the disappearance of these pedogenically permineralized histosols represents the first documented decrease in soil diversity on a vegetated planet the rock record may thus provide important context for the modern loss and degradation of soils

sulfur in the changuinola peat deposit panama as an indicator of d the environments of deposition of peat and coal abstract the sulfur s content of coal is often used to infer aspects of paleoclimate trophic state and proximity to marine influence of the mire in which it was deposited in this study the s content of peat in a large back barrier mire complex on the caribbean coast of panama is related to climatic biological and tectonic factors of the depositional environment earthquake generated subsidence is greatest to the southeast leading to drowning of the deposit beneath almirante bay and 40 of the peat is now below sea level coastal mangrove peats with moderately high s content 1 5 wt s and high salinity 1 0 wt dominate the eastern margin and extend beneath the salt water and shallow marine sediments of the adjoining bay marine influence extends only a short distance onsho e except in the vicinity of brackish blackwater creeks that drain the swamp peats associated with these tidal channels are low in salinity 1 0 wt and very high in s 5 to 14 wt s apparently the result of a biogeochemical chain of s reactions leading to the concentration of c s sulfides the western part of the deposit is domed and the vegetation and the peat are concentrically zoned stunted sawgrass dominated vegetation that produces fibric very low s 0 25 wt s peat occupies the central bog plain around the bog plain mixed forest and palm forest swamps produce dense hemic and fine heroic peat with higher s content 0 250 5 wt s the s content is in proportion to the degree of humification of the peat and both are independent of the ph of the groundwater the distribution of forms of organic and inorganic sulfur in the tropical peats are found to be comparable to published values for temperate and subtropical peats despite differences in vegetation and climate the distribution of high sulfur peats in the eastern part of the deposit and low sulfur peats in the western part and the se nw transgression parallel to the trend of the coastline reflects the regional structural trend of coseismic subsidence greatest to the southeast

ground penetrating radar surveys used in archaeological investigations during 1982 and 1983 two ground penetrating radar surveys were carried out in conjunction with archaeological investigations in canada the first survey was a detailed high resolution radar survey at the site of a sixteenth century basque whaling station on the labrador coast designed to locate the graves of the basques the second was a rapid low resolution reconnaissance survey as part of a prehistory impact assessment program at the site of the new national museum of man in hull quebec both surveys were experimental and were designed to see whether ground penetrating radar would be useful for identifying and locating anomalies of archeological significance radar was successful in detecting archeological anomalies several meters in size at both locations and the high resolution survey was moderately successful in identifying basque graves ongoing work involves comparing radar results with the archaeological investigations to increase the understanding of how radar can be applied to archaeology a

on the fundamental difference between coal rank and coal type abstract this article addresses the fundamental difference between coal rank and coal type while theoretically settled long ago as being different aspects of coal systems science the two concepts are still often confounded in recent years this has resulted in the publication of several works stating that coal type changes with coal rank coal type refers solely to coals depositional origin and the maceral mineral admixture resulting from that origin coal types typically fall in to two categories humic coals developed from peat and sapropelic coals developed from organic mud either type may be allocthonous or autochthonous and within types further refinement of depositional environment can be made coal rank refers to the changes in geochemistry and resultant changes in reflectance caused by increasing thermal maturity of the coal thus it provides an overprint of maturity on existing coal types with proper techniques such as use of crossed polars and etching maceral forms can be differentiated even at high ranks and the original coal type determined

the pennsylvanian tropical biome reconstructed from the joggins formation of nova scotia canada the pennsylvanian langsettian joggins formation contains a diverse fossil assemblage first made famous by lyell and dawson in the mid 19th century collector curves based on c 150 years of observation suggest that the joggins fossil record is relatively complete a key feature of the site is that fossils occur in par autochthonous assemblages within a narrow time interval

paleoclimate controls on late paleozoic sedimentation and peat formation in the central appalachian basin u s a abstract in the central appalachian basin at least two major climate changes affected sedimentation during the late paleozoic stratigraphically these two changes are indicated by the distribution of coal beds the variation in coal quality and the variation in rock lithologies in latest mississippian or earliest pennsylvanian time the climate changed from dry seasonal tropical to ever wet equable tropical the equable climate prevailed into the middle pennsylvanian influencing the morphology and geochemistry in peat forming environments many of the peat deposits which formed under the equable climate were probably domed raised bogs low concentrations of dissolved solids in peat formation water resulted in low buffering capacity organic acids caused acidic ph another climate change occurred in late middle pennsylvanian time when evapopation periodically exceeded rainfall resulting in an increase of both dissolved solids and ph 4 to 7 in surface and near surface water throughout the remainder of the pennsylvanian the surfaces of peat deposits were probably planar not domed water in peat forming and other depositional environments became more nearly neutral the coal beds derived from these peats are highly variable in both ash and sulfur contents drier or more seasonal climates are also indicated by sequences of 1 calcareous sandstone and shale 2 nonmarine limestone that shows shallow water and subaerial exposure features and 3 calcareous paleosols that have caliche characteristics our data and observations indicate that physical depositional environment models for the origin of coal do not adequately explain variations in mineral matter content and composition in commercial quality coal beds in the central appalachian basin stratigraphic variation in mineral matter in coal beds and in syngenetic and early diagenetic minerals in rocks associated with the coal beds appears to be better explained by changes in geochemical conditions of nonmarine sedimentation paleoclimate was a principle control on these geochemical conditions

sea level curve for pennsylvanian eustatic marine transgressive regressive depositional cycles along midcontinent outcrop belt north america at least 55 cycles of marine inundation and withdrawal are recognized in the mid desmoinesian to mid virgilian midcontinent outcrop sequence in north america they range from widespread major cycles classic cyclothems with deep water facies extending across the northern shelf through intermediate cycles persisting as marine horizons across the shelf to minor cycles developed on the lower shelf or as parts of major cycles biostratigraphic differentiation of the cycles should establish interbasinal correlation on a scale fine enough to allow evaluation of differential tectonics and sedimentation sequential groupings of cycles are more irregular than proposed megacyclothems or mesothems but they may be obscured by the distinctness of the major cyclothems estimates of cycle periods range from about 40 to 120 x 10 sup 3 yr for the minor cycles up to about 235 to 400 x 10 sup 3 yr for the major cyclothems the range for all cycles corresponds well to the range of periods of earth s orbital parameters that constitute the milankovitch insolation theory for the pleistocene ice ages and it further supports gondwanan glacial control for the pennsylvanian cycles even though the dominant period of the major pennsylvanian cyclothems is up to four times longer than the dominant 100 000 yr period inmore the pleistocene the shapes of both curves display rapid marine transgression rapid melting of ice caps and slow interrupted regression slow buildup of ice caps which suggest similar linkages between the climatic effects of the orbital parameters and ice cap formation and melting at the two different scales widely separated in time 28 references 3 figures less

separation of tidal and subtidal currents in ship mounted acoustic doppler current profiler observations a simple method is developed to analyze current measurements obtained from a moving platform the need for this is motivated by the now common use of the ship mounted acoustic doppler current profiler adcp to acquire absolute velocity data during an oceanographic survey of a given region the full potential of this new measurement technique is severely hindered when the presence of high frequency phenomena e g tidal or inertial motions prevents a clear visualization of the lower frequency current structure of interest our analysis method is based on a spatial interpolation scheme using arbitrary functions that allows for the tidal current time variability which then permits the tide induced motions to be subtracted from the adcp data to yield the subtidal current field the method also allows nearby moored and drifter current measurements if available to be combined with the shipboard adcp observations in a single analysis to obtain the best description of the tidal and subtidal currents to illustrate this method we present results from the analysis of adcp data taken during oceanographic surveys in two different continental shelf regions the east china sea and the amazon shelf a 5 day conductivity temperature depth ctd and adcp survey was made in the east china sea near the mouth of the yellow sea during january 1986 there the currents were essentially barotropic and dominated by the semidiurnal tide the adcp derived cotidal chart for the m2 12 42 hours component agrees well with existing charts derived empirically from sea level observations or from regional numerical models the adcp derived steady flow is also consistent with the observed density field and indicates little flow in or out of the yellow sea and a transport of about 1 sv toward the tsushima strait two ctd adcp surveys lasting 21 and 23 days were conducted over the amazon shelf during march and may 1990 simultaneously moored current observations were also obtained at three locations along a cross shelf array 200 km north of the amazon river mouth for a common period of at least 2 months february 12 to april 13 over the shelf tidal and subtidal currents were comparable in magnitude our analysis indicates that the tidal currents were essentially barotropic semidiurnal and polarized in the cross shelf direction increasing in magnitude toward the inner shelf where current values of more than 2 m s are common the adcp derived steady currents were aligned in the along shelf direction and strongly influenced by the north brazil current nbc during both adcp surveys the northwestward flowing nbc was transporting more than 2 sv over the shelf at depths shallower than 100 m

from cyclothems to sequences the record of eustasy and climate on an icehouse epeiric platform pennsylvanian permian north american midcontinent the stratigraphic succession of the north american midcontinent contains a high resolution 100 000 year record of sea level and climate change spanning the pennsylvanian permian boundary outcrop based sequence stratigraphic analysis on the upper wabaunsee admire and lower council grove groups in kansas and nebraska reveals a hierarchy of fifty one fifth order meter scale cycles grouped into five fourth order composite sequences fifth order cycles are bounded by subaerial unconformities in nearshore settings and correlative conformities in offshore settings and are therefore very thin depositional sequences lowstand systems tracts observed only in nearshore deposits are expressed as sandy incised valley fills in these meter scale cycles transgressive systems tracts which are dominated by carbonate deposition include coastal evaporites indicating arid climatic conditions highstand systems tracts which are dominated by siliciclastic deposition include thin but persistent coals in muddy coastal successions indicating humid climatic conditions paleosols at sequence boundaries evolve from vertic to calcic indicating climate change from relatively humid to relatively arid conditions during subaerial exposure this indicates that relatively arid climate coincided with eustatic lows while relatively humid climate coincided with eustatic highs on this low latitude platform composite sequences are bounded by subaerial angular unconformities and display a transgressive regressive stacking pattern of meter scale cycles the high resolution stratigraphic record of the midcontinent helps constrain the rate and magnitude of environmental change in ancient icehouse conditions and can serve as a baseline of environmental change for comparison with other coeval successions

paleoecological interpretation of a middle pennsylvanian coal bed in the central appalachian basin u s a abstract at least 180 small spore species assignable to 62 miospore genera have been identified from the middle pennsylvanian hernshaw coal bed in southern west virginia and its stratigraphic equivalent the fire clay coal bed in eastern kentucky the established natural affinities of a majority of these miospore taxa indicate that the hernshaw fire clay peat swamp supported a diverse flora consisting of arborescent and herbaceous lycopods ferns tree like and small varities calamities and cordaites four floral groupings are recognized in the hernshaw fire clay coal bed the inferred paleoecology and vertical stratification of each of these four floral groupings is similar in structure to the phasic floral communities found in modern domed peat systems suggesting that the ancient hernshaw fire clay peat swamp was a domed deposit compositional characteristics petrographic make up ash yield and sulfur content associated with the four groupings are consistent with and support this interpretation where uninterrupted by inorganic partings the hernshaw fire clay coal bed commonly contains basal coal layers dominated by lycospora bearing arborescent lycopods with successive increments showing a progression to a more fern and herbaceous lycopod dominant flora in younger layers these observations are corroborated by petrographic analyses which show the bed to be compositionally stratified increments dominated by lycospora have high vitrinite contents in contrast to increments containing increased percentages of fern and herbaceous lycopod affiliated taxa that are enriched in inertinite macerals the volcanic ash fall preserved as the flint clay parting in the hernshaw fire clay coal bed had a considerable effect on the development of the ancient hernshaw fire clay peat swamp besides interrupting peat formation the presence of an inorganic substrate represent a major change in edaphic conditions within the swamp this disruption is demonstrated by a change in palynflora and by the establishment and proliferation of some plant groups notably cordaites and calamites that may have been better adapted to growth on mineral soils these palynologic and petrographic relationships thought to be indicative of a domed peat swamp origin are not confined to the hernshaw fire clay coal bed but appear to be characteristic of many coal beds in the appalachian basin and also of coal beds in other basins

the so called paleophytic mesophytic transition in equatorial pangea multiple biomes and vegetational tracking of climate change through geological time abstract the paleophytic mesophytic and cenophytic were originally conceptualized as chronostratigraphic intervals not specific floras and were used principally in that way for about 100 years they supposedly reflected massive irreversible biotic changes on land that were thought to have happened about half a geological period prior to the changes in marine faunas that mark the more traditional geological era boundaries the terms were applied initially only to terrestrial rocks from the euramerican portions of equatorial pangea especially parts of central europe where the boundary between the paleophytic and mesophytic the eras of interest here was placed at the top of the german rotliegends more recently the terms have been coopted to describe vegetation types not chronostratigraphic units even to the point where specific linnean ordinal or class level clades evolutionary lineages of plants have been attributed solely to one vegetation type or the other at a global level furthermore the paleophytic mesophytic transition has been recognized in the largely taxonomically distinct vegetation types of temperate as well as the equatorial paleolatitudes the result of this conceptual coopting of terms that already were of questionable value is a blurring of the concepts almost to the point of meaninglessness a reading of the literature indicates confusion in terms of what represents the paleophytic flora vs the mesophytic flora the botanical basis for the floras and the taxonomic scale at which they can be recognized the geographic pattern and temporal correlation of the supposed transition and the evolutionary and ecological significance of the vegetational changes these terms supposedly capture we propose that these terms be completely and utterly abandoned as confusing and worse yet misleading evidence suggests that paleozoic vegetation tracked climate which should not come as a surprise in light of what is known of plant dynamics in the holocene and recent furthermore the evidence for a global paleophytic vs mesophytic vegetation is simply unsubstantiated by the fossil record rather there appears to have been a complex of global species pools reflecting climate at many spatio temporal scales the vegetational changes occurring in the late paleozoic thus can be understood best when examined as spatial temporal changes in biome scale species pools responding to major global climate changes locally and regionally manifested

spatial variability in modern tropical peat deposits from sarawak malaysia and sumatra indonesia analogues for coal petrographic and chemical variability in two tropical low ash domed peat deposits of similar age and physiographic setting but different external morphology were examined as modern analogues for coal both occur in microtidal alluvial to deltaic plain settings support similar arborescent vegetation and have accumulated in the past 5 000 years one deposit is an extremely convex mature done with a surface that rises 10 m above river level the other is a low gradient dome rising only 3 m above river level but with a concave base up to 6 m below both deposits have been eroded by adjacent rivers yet peat in the mature dome has accumulated remote from persistent flooding and exhibits distinctive internal stratigraphy decomposed sapric peat floors the deposits and is overlain by increasingly better preserved woody hemic and a cap of coarse fibrous peat derived from less arborescent vegetation consistent flooding in the low gradient dome has maintained conditions for the accumulation of predominantly woody hemic peat which interfingers with and is overlain by oxidised sapric peat and levee derived clastic sediments peat types in both deposits exhibit distinctive polymodal textures and organo chemical signatures that correspond to botanical input and degree of decay due to the abundance of pre huminite vitrinite macerals in all peat types from these deposits megascopic and microscopic texture is a better discriminator for comparison to ancient coal types it is suggested that the upward vertical sequence of decreasing woodiness and increasing lightness in colour observed in the mature dome might best be compared to sequences observed in tertiary brown coals this typical sequence can be modified or overprinted due to flooding in the burial process

petrographic changes induced by artificial coalification of peat comparison of two planar facies rhizophora and cladium from the everglades mangrove complex of florida and a domed facies cyrilla from the okefenokee swamp of georgia abstract petrographic changes during coalification of three peat samples were investigated by artificial coalification experiments using a semi open reactor system compressions of from 83 to 88 produced dark brown to black shiny flattened pellets exhibiting microscopic banding overall amounts of compression inversely correlated with the framework to matrix ratios f m although certain tissue fragments remained relatively uncompressed due to the presence of tanniniferous cell fillings and also hypothetically to the presence of colorless plant secretions or gelified wall materials that were present in the cells but only recognizable after a change in color during coalification the most distinct microscopic banding longest and widest bands developed in samples of the dome formed peat facies which had the highest framework to matrix ratios of any type and the greatest contents of surface litter composing the framework i e highest s n ratio the planar root dominated rhizophora facies showed the greatest change in microbanding character during coalification in that the numerous lens like bands produced by the compressed roots were very distinct at the 60 2100 psi 121 4 kg cm 2 stage but nearly disappeared at the 175 5000 psi 289 1 kg cm 2 stage this is explained as a result of differences in rates of coalification of the different telinitic precursors in the roots multilinear vitrinization and could explain why roots are significant components of many modern peats and ancient coal ball concretions but are difficult to recognize in bituminous coals similarly separation of cuticles from leaves in modern peat forming environments due to irreversible shriveling and subsequent enhanced microbiological decay partially explains why leaf remains are also difficult to recognize in most coals even those with abundant cutinites microcracks developed in all pellets with dominant orientations of cracks being either perpendicular to induced banding or horizontal to it minute vertical microcracks interpreted as dewatering features were observed primarily in gelinitic bands especially in the most fire prone cladium coal facies but these rarely extended into juxtaposed microlithotypes as did most of the larger vertical cracks horizontal cracks tended to form at microband boundaries almost all humotelinitic and humocollinitic precursors showed some changes in color during artificial coalification with humotelinites exhibiting less or slower changes than humocolinites or humodetrinites finer grained matrix material additionally nearly all dark brown degraded tissues in the peats became dark orange or red during coalification but many of these tissue masses were observed to contain significant amounts of minute inertinite derived from microorganisms pseudomicrinite that only became prominent after coalification and subsequent change in color of surrounding macerals fusinite precursors were only found in the fire prone cladium facies and although the coalified doming generated cyrilla facies exhibited evidence of significant drying events i e occasional bands or parts of bands containing significant pseudomicrinites macrinites and sclerotinites it was dominated by huminitic vitrinitic components liptinites were most common in the coalified dome formed cyrilla facies and displayed a slight qualitative increase in red green fluorescence during coalification and some possible flow of components into nearby cracks changes in mean random reflectance of huminitic macerals although still requiring more data and only measured to the 60 c 2100 psi 121 4 kg cm 2 level indicated increasing directions of change during artificial coalification with humocollinitic macerals progressing from an average of about 0 21 to 0 32 and humotelinitic macerals which consistently had lower inherent reflectances in the peats progressing from 0 15 to 0 25 the above petrographic results along with previously reported chemical results all suggest that the methods that we have used in these experiments have produced changes that might reasonably be expected to occur during natural coalification despite the fact that we have speeded up the process although more work needs to be done to verify and refine these results and to establish a correlation between these artificial coalification steps and true coalification the new observations and conclusions from these studies might still be helpful in constructing models to predict or interpret coal seam characteristics and to establish the timing and release potential of gaseous or liquid hydrocarbons from coals

peat accumulating depositional systems of sarawak east malaysia many coal deposits originate in deltaic estuarine and coastal plain settings and a knowledge of interrelationships between the tectonic and depositional elements active at the time of sediment deposition is necessary to formulate basin scale models the prograding coastal depositional systems of sarawak all contain domed peat accumulating environments in which low ash low sulfur peats are being deposited in areas of active clastic siliciclastic sedimentation these depositional systems are as large as 11 400 km2 and individual peat deposits within systems are in excess of 20 m thick and 1000 km2 in area the geographic positions and drainage basin areas of each depositional system are controlled by fault and fold systems although prograding into the same receiving basin individual system geomorphology is variable and ranges from a wave dominated microtidal delta to a wave dominated meso to macro tidal delta coastal plain system to a tide dominated macrotidal estuarine embayment along a 450 km stretch of coastline system variation is a function of sediment supply shelf and embayment geometry wave climate and tidal range these factors which control depositional system geomorphology also control the resulting long axis orientation of the thick domed peat deposits the surface vegetation and internal characteristics of most domed peat deposits however are similar internal characteristics consist of basal high ash high sulfur degraded peats overlain by low ash low sulfur well preserved peats in vertical profile these systems demonstrate variable responses to late pleistocene holocene sea level rise and in these instances the variation is most attributable to local differences in siliciclastic sediment supply which is a function of the drainage basin area

response of late carboniferous tropical vegetation to transgressive regressive rhythms at joggins nova scotia fossil plant assemblages are described in their sequence stratigraphic context from the upper carboniferous langsettian joggins formation of nova scotia to elucidate ecosystem response to transgressive regressive rhythms results show that rising base level resulted in retrograding submerged coastal mires co dominated by lepidodendron and lepidophloios which were replaced by short lived paralycopodites communities immediately following mire drowning extensive brackish bays existed during early highstand distally fringed by gymnospermous and putative progymnospermous coastal and or upland vegetation late highstand bay filling generated prograding distributary wetlands dominated by flood disturbed lycopsid pteridosperm sphenopsid communities and locally by cordaite mangroves as base level fell well drained alluvial plains were dominated by fire prone cordaite and or sigillaria communities which persisted until the next phase of base level rise this rhythmic ecosystem succession repeatedly occurred on a c 50 200 ka time scale and was probably driven by glacial interglacial climate rhythms

late permian coal bearing carbonate successions in southern china coal accumulation on carbonate platforms abstract late permian coal bearing carbonate successions are extensively developed in southern china microfacies analyses show that these coal bearing carbonate successions were deposited in shallow water carbonate settings comprising restricted platform tidal flat restricted platform subtidal open platform marginal shoal marginal organic reef and basin facies belts coal seams are directly intercalated with carbonate or silicified carbonate rocks in these successions the microfacies of the roof and floor of coal seams are typically tidal flat facies laminated clayey algal clast packstones which suggest that the coal forming peat swamps were developed on or adjacent to tidal flats three settings for coal accumulation can be recognised including shallow flat platform platform interior bank and platform marginal shoal the coal forming materials were most likely derived from mangrove like plants which tolerated variable mixtures of alkaline brackish and fully marine seawater in tide influenced swamps which were similar to modern intertidal mangrove swamps this interpretation is further supported by high organic sulphur contents 6 9 together with elevated concentrations of na 2 o up to 4 36 mgo up to 1 6 to 2 6 and cao up to 2 to 4 the occurrence of dolomite calcite and marine fossils within the coals and their partings demonstrates a close marine association

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

reverse time migration migration of stacked or zero offset sections is based on deriving the wave amplitude in space from wave field observations at the surface conventionally this calculation has been carried out through a depth extrapolation we examine the alternative of carrying out the migration through a reverse time extrapolation this approach may offer improvements over existing migration methods especially in cases of steeply dipping structures with strong velocity contrasts this migration method is tested using appropriate synthetic data sets

pennsylvanian tropical rain forests responded to glacial interglacial rhythms pennsylvanian tropical rain forests flourished during an icehouse climate mode although it is well established that milankovitch band glacial interglacial rhythms caused marked synchronous changes in pennsylvanian tropical climate and sea level little is known of vegetation response to orbital forcing this knowledge gap has now been addressed through sequence stratigraphic analysis of megafloral and palynofloral assemblages within the westphalian d cantabrian sydney mines formation of eastern canada this succession was deposited in a low accommodation setting where sequences can be attributed confidently to glacio eustasy results show that long lived low diversity peat mires dominated by lycopsids were initiated during deglaciation events but were mostly drowned by rising sea level at maximum interglacial conditions only upland coniferopsid forests survived flooding without significant disturbance mid to late interglacial phases witnessed delta plain progradation and establishment of high diversity mineral substrate rain forests containing lycopsids sphenopsids pteridosperms cordaites and tree ferns renewed glaciation resulted in sea level fall paleovalley incision and the onset of climatic aridity glacial vegetation was dominated by cordaites pteridosperms and tree ferns hydrophilic lycopsids and sphenopsids survived in paleovalley refugia findings clearly demonstrate the dynamic nature of pennsylvanian tropical ecosystems and are timely given current debates about the impact of quaternary glacial interglacial rhythms on the biogeography of tropical rain forest

changing patterns of pennsylvanian coal swamp vegetation and implications of climatic control on coal occurrence abstract improved regional and interregional stratigraphic correlations of pennsylvanian strata permit comparisons of vegetational changes in euramerican coal swamps the coal swamp vegetation is known directly from in situ coal ball peat deposits from more than 65 coals in the united states and europe interpretations of coal swamp floras on the basis of coal ball peat studies are extended to broader regional and stratigraphic patterns by use of coal palynology objectives of the quantitative analyses of the vegetation in relation to coal are to determine the botanical constituents at the peat stage and their environmental implications for plant growth and peat accumulation morphological and paleoecological analyses provide a basis for deducing freshwater regimes of coal swamps changes in composition of pennsylvanian coal swamp vegetation are quire similar from one paralic coal region to another and show synchrony that is attributable to climate paleobotany and paleogeography of the euramerican province indicate a moist tropical paleoclimate rainfall runoff and evapotranspiration were the variable climatic controls in the distribution of coal swamp vegetation peat accumulation and coal resources in relative terms of climatic wetness the pennsylvanian period is divisible into five intervals which include two relatively drier intervals that developed during the lower middle and middle upper pennsylvanian transitions the climate during early pennsylvanian time was moderately wet and the median in moisture availability early middle pennsylvanian was drier probably seasonally dry wet late middle pennsylvanian was the wettest in the midcontinent early late pennsylvanian was the driest and late late pennsylvanian was probably the wettest in the dunkard basin the five climatic intervals represent a general means of dividing coal resources within each region into groups with similar botanical constituents and environments of peat accumulation regional differences in basinal geology and climate were significant variables but the synchronous control of paleoclimate was of primary importance

distribution of vertical velocity inferred from secondary flow in a curved tidal channel high resolution observations from the curved tidal channel of the otago harbour shows secondary flows up to 20 of the primary flow and vertical velocity inferred from secondary flow up to 1 of the primary flow this vertical velocity is inferred on a much finer scale than previous works the spatial pattern of this vertical velocity is upward on the inside and downward on the outside of the bend consistent with previous laboratory flume measurements linear regression rp 0 95 shows the cross channel distribution of the observed secondary flow can be resolved from the horizontal adcp measurements well enough to be consistent with the cross channel distribution of secondary flow derived from the observed primary flow using the model of kalkwijk and booij 1986 linear regression rp 0 80 shows the vertical velocity inferred from observed secondary flow is consistent with vertical velocity derived from the observed primary flow using the model of kalkwijk and booij 1986 this also shows the cross channel distribution of the observed secondary flow is resolved well enough from the horizontal adcp measurements to be able to infer the vertical velocity from mass continuity the required horizontal resolution is made possible by radial basis function rbf smoothing and spatial interpolation that allows for continuity of the spatial derivatives modeling trajectories using channel dimensions and velocity field values equivalent to the observations show that 3 dimensional secondary circulation forms a loose helical flow pattern

paleopedologic and paleohydrologic records of precipitation seasonality from early pennsylvanian underclay paleosols u s a underclays in the crooked fork group lower pennsylvanian atokan langsettian in eastern tennessee u s a are paleosols associated with fourth order depositional sequences that record changing paleohydrologic conditions during their formation climate changes possibly milankovitch driven resulted in evolution of soil landscapes from well drained seasonally wet floodplains and delta plains dominated by vertic vertisol like paleosols to very poorly drained everwet swamps dominated by sideritic gley paleosols coals paleohistosols cap most underclays and record peat swamp development during everwet conditions followed by marine submergence pedogenic slickensides and angular blocky ped structures in conjunction with illuviated clay pore fillings and sepic plasmic microfabric indicate an initial better drained phase of paleosol development stage i gley overprinting characterized by drab low chroma paleosol colors fe reduction in upper portions of paleosols sideritic rhizocretions sphaerosiderite and pyrite nodules extensive leaching and translocation of alkali and alkaline earth elements and kaolinitization of smectites and hydroxy interlayer vermiculite hiv indicate a later poorly drained stage of paleosol development characterized by saturated conditions moderate to low eh and low ph stage ii as well as peat swamp development lastly burial and juxtaposition of marine facies on top of terrestrial deposits terminated paleosol and peat development stage iii paleosols likely formed under conditions of marked seasonality of rainfall judging from both modern analog systems in sumatra and pennsylvanian paleoclimate models the chemical index of alteration without potash cia k was used as a proxy for atokan paleoprecipitation estimated as 1300 mm yr this estimate is comparable with mean annual precipitation map in modern tropical to subtropical rainy environments

glacial eustatic sea level curve for early late pennsylvanian sequence in north central texas and biostratigraphic correlation with curve for midcontinent north america at least 30 transgressive regressive cycles of deposition are recognized from the upper desmoinesian east mountain shale to the mid virgilian wayland shale in north central texas maximum regressive deposits are typically paleosol mudstones and fluvial sand stones maximum transgressive deposits are typically widespread ammonoid bearing conodont rich dark phosphatic shales in more major cycles and persistent fossiliferous shales or limestones overlying terrestrial deposits in more minor cycles delta complexes dominate the regressive sequences of many cycles using biostratigraphic criteria of first last sole or acme occurrence of ammonoid conodont and fusulinid taxa we correlate 17 cycles in the texas sequence directly with 17 glacial eustatic cycles of similar magnitude in the northern midcontinent this correlation suggests that glacial eustacy was the basic control over the cyclic sequence in texas that tectonic masking of the eustatic signal by nearby orogenic movement in texas was negligible and that delta shifting though conspicuous was only a secondary control over the cyclicity there minor cycles recognized between the correlated cycles also match well enough between texas and the midcontinent to further discount potential tectonic or deltaic masking of glacial eustatic cyclicity this strengthens the likelihood of correlating glacial eustatic events across larger parts of north america and perhaps with other parts of the world

comparison of drier to wetter interval estuarine roof facies in the eastern and western interior coal basins usa abstract many of the carboniferous coals in the eastern interior of the us are associated with siliciclastic roof facies that were deposited within a fluvio estuarine transition these facies include a variety of rhythmites some of which exhibit tidal cycles drier interval coals westphalian b c stephanian tend to be more laterally restricted and more commonly are associated with paleovalleys conversely wetter interval coals westphalian d are very widespread and are not restricted to paleovalleys throughout the lake carboniferous wet paleoclimates associated with these coals lead to valley incision during sea level lowstand when large tropical rivers downcut older sediments deposited during previous sea level highstands during subsequent rise of sea level these fluvial valleys were flooded and converted to estuaries where tidal ranges and sedimentation rates were significantly amplified based on modern analogs and interpretation of many examples of carboniferous tidal rhythmites the localized depositional rates in these settings are exceptionally high the estuaries became sediment sinks trapping sediment that is pumped in from both fluvial and marine sources as a result sedimentation readily keeps pace with rising baselevel extensive intertidal flats and shallow subtidal flats are created and prograde over the valley confined mires thick tidal cycles and upright trees some with attached foliage record rapid burial of mires this model is supported with examples of roof facies from the westphalian b c of the eastern interior basin and the stephanian of the western interior basin in these areas facies within each cycle range from well developed extensive paleosols and coals to widespread marine shales or limestones variations in both sea level and climate resulted in a complex history of valley fill during which coals could be developed at any time except during widespread flooding minable low sulfur and low ash coals occur but the coals are relatively thin and discontinuous conversely the westphalian d coals are very widespread and significant peat accumulations were not confined to paleovalleys nonetheless the lowest sulfur coals are related to rapid deposition of roof facies that occurred within the paleovalley whereas high sulfur coals were formed in areas of lower sedimentation rate of roof facies that occurred beyond the confines of the paleovalley

palaeoenvironments and palaeoecology of the early pennsylvanian lancaster formation fern ledges of saint john new brunswick canada the pennsylvanian lancaster formation fern ledges of saint john new brunswick canada contains a world famous fossil biota largely unstudied since the works of hartt dawson matthew and stopes in the mid nineteenth to early twentieth century we present new data concerning biostratigraphy taxonomy palaeoenvironments and palaeoecology megafloral assemblages suggest a mid to late langsettian age for the succession making it approximately coeval with the classic joggins formation of nearby nova scotia facies analysis suggests deposition on a tectonically influenced coastal plain whose braided channels drained into a shallow brackish gulf most of the historical fossil collections are derived from flooding surfaces formed by abrupt subsidence events along the coastline three communities are recognized phoronids crustaceans and xiphosurans lived in brackish coastal waters a lowland community of gastropods insects arachnids and myriapods inhabited coastal forests coastal vegetation was dominated by shrubby cordaitaleans and pteridosperms whereas ferns sphenopsids and lycopsids were rare an upland or dryland community discernible from allochthonous assemblages comprised forests of giant cordaitaleans archaic pteridosperms and plants of uncertain affinity

relationship between petrographic and chemical properties and coal seam geometry hance seam breathitt formation southeastern kentucky the upper hance coal seam in southeastern kentucy was used as a template to examine the spatial distribution of ash yield sulfur content and petrographic constituents relative to the geometry of the deposit geometric characteristics include thinning and splitting of the two main benches leaders and riders analytical data showed the thick non split portions of the coal body to be low in ash and sulfur as well as vitrinite content whereas the thinned and split margins were higher in ash sulfur and vitrinite content these relationships suggest that thick non split portions of the upper hance peat accumulated in areas isolated from detrital influx while thinner marginal peat was subject to intermittent flooding from adjacent channels marginal peat was derived from larger trees which flourished at the mire s edge in the presence of adequate nutrients whereas only stunted vegetation subsisting in the nutrient depleted center contributed to interior peat accumulation ponds formed on the sparsely vegetated mature surface of the bog s interior the petrographic and chemical character of the hance coal body is analogous to ombrogenous domed peats which characteristically contain higher concentrations of inorganics at the periphery of the deposit

paleobotanical and paleoecological constraints on models of peat formation in the late carboniferous of euramerica abstract the dominant plants of the late carboniferous lowland tropics were taxonomically and structurally distinct from those of any later time periods dominance was distributed among lycopsids ferns sphenopsids pteridosperms and cordaites and each of these groups had distinctive and different ecological preferences and amplitudes peat forming habitats were dominated by lycopsids throughout the westphalian with a significant cordaitean element in the middle westphalian during the stephanian tree ferns were dominant following major extinctions near the westphalian stephanian transition each of the major plant groups had distinctive architectures and tissue composition trees contributed up to 95 of the peat biomass and tree forms of lycopsids psaronius and medullosa lack good modern analogues the cordaites were the only woody plant group to contribute significantly to peat and then only during the mid westphalian structurally wood like lycopsid bark is the major woody tissue encountered in most westphalian coals tree ferns and pteridosperms were largely parenchymatous in construction the stigmarian root systems of lycopsids also were largely parenchymatous the tissue structure of these dominant plant suggests the need for extreme caution in the inference of mire ecological conditions or vegetational structure from coal petrographic data peat formed under arborescent ferns or pteridosperms or peat repeatedly exposed to decay and rerooting by stigmarian root systems of lycopsids would have a distinctly non woody signature and yet would have formed in a forested environment a summary is presented of the autecology and synecology of mire plants emphazing the structural framework provided by lycopsids during the westphalian certain constraints in the links between peat biomass and miospore palynology are discussed in terms of over representation under representation and non representation the formulation of smith s four phase hydroseral model is discussed and compared with more recent data available from plant paleoecology the current debate over an ombrotrophic vs rheotrophic origin of late carboniferous peats relies in large part on paleobotanical data almost entirely palynological in combination with petrographic analyses ecological studies of miospores and of coal ball and compression macrofossils and the linkage of miospores to source plants permit the re evaluation of mire successional models evidence for tree lycopsids sphenopsids pteridosperms and cordaites suggests growth mainly in rheotrophic mires tree ferns are likely candidates for growth in domed mires although evidence is ambiguous and some tree ferns clearly grew under rheotrophic conditions densospores produced by at least sporangiostrobus lycopsid subtrees have been considered diagnostic of ombrotrophic conditions abundant evidence refutes this simplistic interpretation and suggests broad ecological amplitudes for densospore producers including growth under rheotrophic conditions although plant fossils alone can not resolve most of the major debates in modern coal geology paleobotany does contribute significantly to our understanding of ancient mires an approach combining paleobotanical data with petrography sedimentology and geochemistry on a case by case basis is most likely to produce a clear picture

impact of longer term modest climate shifts on architecture of high frequency sequences cyclothems pennsylvanian of midcontinent u s a abstract pennsylvanian glacioeustatic cyclothems exposed in kansas and adjacent areas provide a unique opportunity to test models of the impact of relative sea level and climate on stratal architecture a succession of eight of these high frequency sequences traced along dip for 500 km reveal that modest climate shifts from relatively dry seasonal to relatively wet seasonal with a duration of several sequences 600 000 to 1 million years had a dominant impact on facies sediment dispersal patterns and sequence architecture the climate shifts documented herein are intermediate both in magnitude and duration between previously documented longer term climate shifts throughout much of the pennsylvanian and shorter term shifts described within individual sequences climate indicators are best preserved at sequence boundaries and in incised valley fills of the lowstand systems tracts lst relatively drier climate indicators include high chroma paleosols typically with pedogenic carbonates and plant assemblages that are dominated by gymnosperms mostly xerophytic walchian conifers the associated valleys are small 4 km wide and 20 m deep and dominated by quartz sandstones derived from distant source areas reflecting large drainage networks transgressive systems tracts tst in all eight sequences generally are characterized by thin extensive limestones and thin marine shales suggesting that the dominant control on tst facies distribution was the sequestration of siliciclastic sediment in updip positions highstand systems tracts hst were significantly impacted by the intermediate scale climate cycle in that hsts from relatively drier climates consist of thin marine shales overlain by extensive thick regressive limestones whereas hsts from relatively wetter climates are dominated by thick marine shales previously documented relative sea level changes do not track the climate cycles indicating that climate played a role distinct from that of relative sea level change these intermediate scale modest climate shifts had a dominant impact on sequence architecture this independent measure of climate and relative sea level may allow the testing of models of climate and sediment supply based on modern systems

sedimentology of the changuinola peat deposit organic and clastic sedimentary response to punctuated coastal subsidence an extensive peat deposit on the caribbean coast near changuinola panama has developed in an area subject to periodic earthquake driven coseismic subsidence thick low ash low sulfur peat is accumulating immediately behind an aggrading and prograding barrier system and adjacent to a flood prone sediment laden river measurements of changes in local sea level as a result of a recent april 1991 earthquake reveal 30 50 cm of subsidence greatest at the southeastern extent of the study area where the peat surface is submerged to a depth of 3 m beneath the shallow waters of almirante bay transgression is proceeding from southeast to northwest parallel to the trend of the coast and the long axes of both the peat deposit and the major sand bodies in the eastern part of the deposit the effects of sea level rise are evident in the degree of humification mineral matter and sulfur content of mangrove and back mangove peats offshore and immediately adjacent to the marine margin and in peats associated with brackish tidal channels that drain the deposit however most of the deposit shows no indications of marine influence even though 40 of the peat is below present sea level the western section of the deposit has evolved from low lying palm swamps which originated in swales on the barrier bar into an oligotrophic bog plain with a water table elevated 6 75 m above sea level as the mire evolved transitions in vegetation resulted in transitions in peat types highly humified forest swamp and palm swamp peats underlie and surround well preserved fibric sedge peats and create a partial hydrological bounding surface that restricts subsurface drainage from the central bog the high water table and elevated topography of the mire and the low permeability and erosion resistance of the dense woody peat effectively insulate most of the deposit from both clastic influx and the extensive intrusion of rising marine waters it is evident that thick peat and hence coal deposits can accumulate due to tectonically driven punctuated subsidence without leaving a record of high clastic input within the peat even immediately adjacent to environments of active clastic deposition

a late paleozoic fossil forest from the southern andes argentina abstract an anatomical and ecological study of a late pennsylvanian early permian assemblage of silicified trunks from the san ignacio formation of southern andean cordillera is detailed this stratigraphic unit has been divided in three facies associations the silicified trunks are abundant in the middle part of the facies association c limestones shales and volcanics forming a persistent forested stratigraphic level anatomical information integrated with sedimentological data has allowed reconstruction of a plant community that grew on the westernmost margin of gondwana the paleoforest grew in wetland environments where a taphocoenosis of only permineralized trunks and stumps has been preserved based on characters of the stem and roots the trees are cordaitaleans though distinct from other members of this group vascular traces exhibit tracheids arranged in circular patterns indicating auxin regulation of axial growth and probably the presence of epicormic shoots these fossil trees also preserve anatomical evidence of plant arthropod interactions and rootlets invading the decaying wood indistinct growth rings as well as additional indirect evidence indicate that this ecosystem experienced an overall humid warm climatic regime

three dimensional tidal flow around headlands field measurements of tidal flow around a headland indicate secondary circulation induced by flow curvature the secondary flow defined to be the flow in the plane normal to the direction of the vertically averaged current is directed toward the headland near the bottom and seaward near the surface consistent with theoretical predictions the strength of the secondary flow varies from 5 to 15 of the streamwise flow it is strongest when the water column is stratified because of both the enhanced shear of the streamwise flow and the reduced frictional damping of the secondary flow the transverse exchange accomplished by the secondary flow significantly influences the structure of the streamwise flow causing a broadening of the transverse shear and changing the horizontal and vertical distributions of momentum it may also have a significant influence on horizontal dispersion in the vicinity of headlands

uplands lowlands and climate taphonomic megabiases and the apparent rise of a xeromorphic drought tolerant flora during the pennsylvanian permian transition abstract the late mississippian and pennsylvanian have been referred to as the coal age due to enormous paleotropical peat accumulations coal beds numerous fossil floras have been collected from these coals and their associated seat earth paleosols and roof shales over more than two centuries leading to the inference of vast swampy wetlands covering the pangean tropics during the pennsylvanian in contrast the permian tropics are characterized as more arid with sparser and more heterogeneous vegetation than inferred for the pennsylvanian in the tropics the pennsylvanian to permian transition has been described as a changeover from a pteridophyte dominated paleophytic flora to a seed plant dominated mesophytic flora this view notwithstanding floras dominated by xeromorphic seed plants also are well known from the pennsylvanian tropics some authors have characterized these plants as being occupants of uplands subsequently transported into basinal lowland preservational environments in this model uplands are well drained causing areas of drought under otherwise everwet climates in this paper we present an alternative interpretation that the apparent transition in pennsylvanian permian tropical vegetation reflects two types of taphonomic megabias first is a preservational megabias strongly favoring the vegetation of humid climates over that of seasonally dry climates accordingly tropical plant preservational potential fluctuated in concert with late paleozoic ice age glacial interglacial oscillations and contemporaneous sea level and climatic changes second is an analytical megabias strongly favoring the discovery and collection of the wetland biome from pennsylvanian strata overlooking the less frequently and more poorly preserved drought tolerant biome by permian times vast wetlands and their fossil record had largely disappeared from central pangea although continuing in cathaysia making drought tolerant vegetation more visible to searchers without changing its preservational circumstances we demonstrate that the upland model is untenable being inconsistent with the principles of plant biogeography and with geological aspects of the fossil record

are coal balls rare a cyclostratigraphic analysis of coal ball occurrence in north america abstract from the perspective of phanerozoic time coal balls are rare apparently limited to a 24 m y interval 323 299 ma in the pennsylvanian and earliest permian yet within this interval coal balls occur in many coals approximately 82 transgressive regressive sedimentary cycles have been described for the midcontinent illinois and appalachian basins of north america during the mid to late pennsylvanian one third 27 82 have coal balls including 57 of major cycles 36 of intermediate cycles and 16 of minor cycles coal ball occurrence in the donets basin is similar over an interval of about 4 m y 315 311 ma latest bashkirian to mid moscovian 39 11 28 of transgressive regressive cycles have coal balls as north american paleoclimate became drier tree ferns replaced lycopsids as the dominant plant in peat swamps at the desmoinesian missourian boundary and coal ball occurrence declined overall 47 of cycles 19 40 with lycopsid or cordaitean dominance have coal balls whereas 19 8 42 of cycles with tree fern dominance have coal balls p this pattern may reflect the relative abundance of coal in the late pennsylvanian with drier paleotropical climates in the missourian virgilian leading to less paleotropical coal fewer mines and a lower probability of discovering missourian and virgilian coal balls however average cycle duration decreased from 150 kyr in the desmoinesian to 100 kyr in the missourian and virgilian and faster rates of relative sea level rise could have affected coal ball abundance particularly if coal balls formed in marine swamps with more rapid transgression leading to thinner coals or to freshwater coals directly overlain by marine sediments rygel et al 2008 suggested that missourian virgilian cycles recorded more erosional relief than desmoinesian cycles consistent with increased amplitude and rates of sea level rise during each glacial eustatic cycle changes in missourian virgilian cycles may have been augmented by stratigraphic attenuation as sediment filled the antecedent topography

geochemistry of autochthonous and hypautochthonous siderite dolomite coal balls foord seam bolsovian upper carboniferous nova scotia canada abstract the 11 13 m thick foord seam in the fault bounded stellarton basin nova scotia is the thickest seam from the euramerican floral province known to contain coal balls in addition to the first discovery of autochthonous coal balls in the foord seam nova scotia its shale parting also contains hypautochthonous coal balls with histologically preserved plant structures the coal ball discovery helps fill a stratigraphic gap in coal ball occurrences in the upper carboniferous bolsovian of euramerica the autochthonous and hypautochthonous coal balls have a similar mineralogical composition and are composed of siderite 81 100 dolomite ankerite 0 19 minor quartz and illite and trace amounts of calcite similar is also their permineralizing mineralogy which consists of dolomite ankerite and siderite their low pyrite content and carbonate mineralogy and nonmarine origin differentiates the foord seam coal balls from other euramerican coal ball occurrences a preliminary geochemical model which is based on oxygen and carbon isotopic data indicates that siderite in both the autochthonous and hypautochthonous coal balls is of very early diagenetic nonmarine origin from 13 c enriched bicarbonate derived from bacterial methanogenesis of organic matter

carbonate petrology and geochemistry of pennsylvanian coal balls from the kalo formation of iowa abstract coal balls are carbonate and pyrite concretions enclosing uncompressed peat primarily found in pennsylvanian and earliest permian paleotropical coals petrographic and microprobe analysis of coal balls from the mid moscovian latest atokan or earliest desmoinesian williamson no 3 mine kalo formation from lucas county iowa indicates that pyrite was the earliest mineral to form followed by high mg calcite average 13 9 mol mgco 3 which is also high in sr 700 1500 ppm suggesting that the kalo formation coal balls formed in response to the incursion of marine water into the mire the high mg calcite has an unusual growth habit radiating arrays of bladed polycrystals which look like distorted triangles with elongated apices when cut parallel to the basal plane these high mg calcite polycrystals have low mg non ferroan calcite rims consistent with diagenesis in meteoric water the presence of early high mg and low mg non ferroan calcite in the williamson no 3 coal balls suggests that these coal balls formed in a hydrologically dynamic environment most of the remaining cements in the kalo formation coal balls are low mg ferroan calcite consistent with burial diagenesis these cements retain regions of low mg and high mg calcite suggesting that they are neomorphs of the early high mg calcite cement fibers in the vascular bundle supports of cordaites principalis leaves have narrow rims of dolomite that appear unique to this species the presence of high mg calcite in the williamson no 3 coal balls supports the stopes and watson phil trans roy soc london b 1909 200 167 218 model of coal ball formation as a result of incursions of marine water into coastal mires it conflicts with stable isotopic data which suggests that most coal ball cements formed in meteoric water however in our samples the most common cement is diagenetically altered low mg ferroan calcite which might yield meteoric oxygen isotopic values excellent preservation of plant fossils in coal balls is not necessarily correlated with the presence of original cement

palynological correlation of major pennsylvanian middle and upper carboniferous chronostratigraphic boundaries in the illinois and other coal basins

cordaiteans in paleotropical wetlands an ecological re evaluation abstract cordaiteans in cordaite dominated permineralized peat from pennsylvanian coals in iowa have been reconstructed as mangroves using root anatomy peat taphonomy and geochemical data macrofloral palynofloral and conodont biostratigraphy indicate that these peats come from the latest atokan blackoak coal and earliest desmoinesian cliffland coal mid moscovian both in the kalo formation thus their depositional setting can be used to evaluate the mangrove hypothesis in recent mires thick mangrove peats have accumulated in tropical to subtropical carbonate systems in contrast thick tropical freshwater peats have accumulated in siliclastic systems kalo formation coals which we interpret as freshwater deposits formed in siliciclastic depositional settings similar to those of modern tropical freshwater peat and to other pennsylvanian coals in north america interpreted as freshwater deposits in the late atokan and earliest desmoinesian mid moscovian cordaiteans and tree ferns predominated in the western interior and illinois basins lycopsids and cordaiteans predominated in the appalachian and donets basins the scarcity of lycopsid only mires in north america during the late atokan earliest desmoinesian mid moscovian suggests drier climates than during the mid to late desmoinesian late moscovian rather than indicating mangrove swamps cordaite dominated peat may indicate climates with a low rain season although most plants in cordaite dominated peat probably grew in freshwater coastal mires in climate zones with seasons of low rain may harbor mangrove taxa the changuinola swamp of panama a modern peat accumulating wetland that has a low rain season is a possible analog of ancient cordaite dominated mires in changuinola most plants require freshwater however mangroves sustained by salt water influx into the swamp grow along the seaward edge and along blackwater creeks the low rain season hypothesis has implications for understanding rainfall amount and continuity during pennsylvanian cyclothem deposition the floral succession in diverse cordaite coals from cordaiteans to tree ferns to lycopsids suggests increasingly wet climate during coal accumulation the position of these coals immediately above the sequence boundary suggests humid climate during early glacial melting for these cyclothems

magnitude of climate variability during middle pliocene warmth a palaeoclimate modelling study abstract the nature and magnitude of climatic variability during the period of middle pliocene warmth ca 3 29 2 97 ma is poorly understood we present a suite of palaeoclimate modelling experiments incorporating an advanced atmospheric general circulation model gcm coupled to a q flux ocean model for 3 29 3 12 and 2 97 ma bp astronomical solutions for the periods in question were derived from the berger and loutre bl2 astronomical solution boundary conditions excluding sea surface temperatures ssts which were predicted by the slab ocean model were provided from the usgs prism2 2 2 digital data set the model results indicate that little annual variation 0 5 c in ssts relative to a control experiment occurred during the middle pliocene in response to the altered orbital configurations annual surface air temperatures also displayed little variation seasonally surface air temperatures displayed a trend of cooler temperatures during december january and february and warmer temperatures during june july and august this pattern is consistent with altered seasonality resulting from the prescribed orbital configurations precipitation changes follow the seasonal trend observed for surface air temperature compared to present day surface wind strength and wind stress over the north atlantic north pacific and southern ocean remained greater in each of the pliocene experiments this suggests that wind driven gyral circulation may have been consistently greater during the middle pliocene the trend of climatic variability predicted by the gcm for the middle pliocene accords with geological data however it is unclear if the model correctly simulates the magnitude of the variation this uncertainty is derived from a the relative insensitivity of the gcm to perturbation in the imposed boundary conditions b a lack of detailed time series data concerning changes to terrestrial ice cover and greenhouse gas concentrations for the middle pliocene and c difficulties in representing the effects of climatic history in snap shot gcm experiments

stratigraphic and interregional changes in pennsylvanian coal swamp vegetation environmental inferences abstract quantitative analysis of pennsylvanian coal swamp vegetation provides a means of inferring organization and structure of communities distribution of these communities further provides inferences about environmental factors including paleoclimate our observations are based on in situ structurally preserved peat deposits in coal ball concretions from 32 coal seams in the eastern one half of the united states and from several seams in western europe and on spore assemblages from more than 150 seams there were three times of particularly significant and nearly synchronous vegetational changes in the midcontinent and appalachian coal regions during the pennsylvanian period each was different in kind and magnitude the first marked changes occurred during the early part of the middle pennsylvanian with the fluctuating decline in the high level of lycopod dominance the abundance of cordaites increased there was a rise in the occurrences of the lycopod herbs to form intercalated marshlands and an overall increase in floral diversity changes ensuing from this time also include shifts in dominant species of lycopod trees and a sustained rise in abundance and diversity of tree fern spores the next significant time of change was during the middle part of the middle pennsylvanian representing both a culmination of earlier trends and expansions of cordaites in the midcontinent where there was a maximum change in species without net loss of diversity tree ferns and medullosan pteridosperms attained subdominant levels of abundance and diverse lycopod species dominated except in the atokan desmoinesian transition of the midcontinent the third and sharpest break occurred near the middle late pennsylvanian boundary when extinctionsof the dominant coal swamp lycopods allowed development of tree fern dominance the late pennsylvanian coal swamps apparently were colonized or recolonized mainly by species from outside coal swamps rather than by the survivor populations of the middle pennsylvanian swamps paralleling the changes in floras through the pennsylvanian are changes in preservational aspects of the peat these include a decline in shoot root ratios from approximately 1 to

the changuinola peat deposit of northwestern panama a tropical back barrier peat coal forming environment abstract a large 82 km 2 thick 8 m low ash low sulfur peat deposit has formed on the northwestern coast of panama its low ash and low sulfur contents can be attributed partly to 1 doming 2 the occurrence of a relatively continuous marine blocking beach barrier shoreline feature and 3 leaching of the mineral matter this deposit is roughly rectangular in shape and oriented with its longest axis parallel to the beach barrier shoreline it would produce an economic coal bed that is bright and finely banded in its thickest central region and more coarsely banded at its margins its northwestern margin would be characterized by interfingering of coal with sandstone and siltstone of the changuinola river flood plain whereas its southeastern boundary would be characterized by truncation of the upper part of the seam by marine to brackish shales siltstones and carbonates that were derived from almirante bay total sulfur was found to be very low less than 0 2 dry wt except in a few places in these rare cases nearly all of the sulfur was pyritic and the total sulfur content was anomalously high 14 although the general tendency was for total sulfur to increase wherever the deposit was influenced by marine conditions one case was found where sulfur was high at the base of an inland freshwater peat core which suggests either a hidden marine influence or the need for some new mechanism to explain sulfur enrichment in such an anomalous case differences in inherent fixed carbon contents and calorific values due to changes in peat type and analytical uncertainties tended to mask seamwide trends in these parameters however fixed carbon contents and calorific values showed a slight tendency to increase with depth especially if plotted for single peat types vitrinite reflectance within the hypothetical changuinola coal bed would be expected to increase as follows 1 toward the margins of the deposit 2 toward the bottom and top of the bed and 3 toward stream channels or tidal inlets

the terrestrial landscapes of tetrapod evolution in earliest carboniferous seasonal wetlands of se scotland abstract the lower mississippian tournaisian ballagan formation in se scotland yields tetrapod fossils that provide fresh insights into the critical period when these animals first moved onto land the key to understanding the palaeoenvironments where they lived is a detailed analysis of the sedimentary architecture of this formation one of the thickest and most completely documented examples of a coastal floodplain and marginal marine succession from this important transitional time anywhere in the world palaeosols are abundant providing a unique insight into the early carboniferous habitats and climate more than 200 separate palaeosols are described from three sections through the formation the palaeosols range in thickness from 0 02 to 1 85 m and are diverse most are entisols and inceptisols 63 indicating relatively brief periods of soil development gleyed inseptisols and vertisols are less common 37 vertisols are the thickest palaeosols up to 185 cm in the ballagan formation and have common vertic cracks roots are abundant through all the palaeosols from shallow mats and thin hair like traces to sporadic thicker root traces typical of arborescent lycopods geochemical isotope and clay mineralogical analyses of the palaeosols indicate a range in soil alkalinity and amount of water logging estimates of mean annual rainfall from palaeosol compositions are 1000 1500 mm per year the high mean annual rainfall and variable soil alkalinities contrast markedly with dry periods that developed deep penetrating cracks and evaporite deposits it is concluded that during the early carboniferous this region experienced a sharply contrasting seasonal climate and that the floodplain hosted a mosaic of closely juxtaposed but distinct habitats in which the tetrapods lived the diversification of coastal floodplain environments identified here may link to the evolution and movement of tetrapods into the terrestrial realm

the search for graves over the decades grave markers in old cemeteries have been lost geophysical exploration can sometimes locate the unmarked burials the two techniques which may be best for this search are a ground penetrating radar survey and a soil conductivity survey a ground penetrating radar survey with its capability for estimating the depth and shape of buried objects is particularly suitable with an electromagnetic induction survey the disturbed soil in the grave shaft can sometimes be detected as a change in electrical conductivity both of these surveys also can locate large metal objects these surveys have limitations at some sites the radar cannot profile deeply enough at others the soil strata are so complex that graves cannot be distinguished a conductivity survey can be degraded by metallic trash and other small objects in the topsoil it can give the best results where the earth is distinctly stratified results from nine surveys are illustrated here the sites are all in the u s a and the gra

the sedimentary record of palaeoenvironments and sea level change in the gulf of carpentaria australia through the last glacial cycle abstract environmental evolution of the gulf of carpentaria region the world s largest tropical epicontinental seaway through the last glacial cycle has been determined from a series of six sediment cores these cores form the focus of a multi disciplinary study to elucidate sea level climate and environmental change in the region the sedimentary record reveals a series of facies including open shallow marine marginal marine estuarine lacustrine and subaerial exposure throughout the extent of the basin during this period the partial or complete closure of the central basin from marine waters results from sea level falling below the height of one or both of the sills that border the gulf the arafura sill to the west 53 m below present sea level bpsl and torres strait to the east 12 m bpsl the extent and timing of these closures and restriction of the shallow waterbody within are intrinsic to local ocean circulation available latent heat transport and the movement of people and animals between australia and new guinea whilst the occurrence of the palaeo lake carpentaria has previously been identified this study expands on the hydrological conditions of the lacustrine phases and extends the record through the last interglacial detailing the previous sea level highstand mis 5 5 and subsequent retreat when sea levels were low during the mis 6 glacial period the gulf was largely subaerially exposed and traversed by meandering rivers the mis 5 transgression 130 ka bp led to marine then alternating marine estuarine conditions through to mis 4 70 ka bp when a protracted lacustrine phase of varying salinity and depth area and including periods of near desiccation persisted until about 12 2 cal ka bp the lake expanded to near maximum size 190 000 km 2 following the intensification restoration of the australian monsoon at 14 ka bp this lake full phase was short lived as by 12 2 cal ka bp marine waters were entering the basin coincident with the progressive sea level rise fully marine conditions were restored by about 10 5 cal ka bp by westward connection to the arafura sea indian ocean whereas connections to the pacific ocean coral sea did not occur until about 8 cal ka bp

full wave calibration of time and frequency domain ground penetrating radar in far field conditions full wave modeling of ground penetrating radar gpr data using green s functions for wave propagation in planar layered media and antenna characteristic global reflection and transmission functions for describing far field antenna effects including antenna medium interactions has shown a great potential for nondestructive characterization of soils and materials the accuracy of the retrieved parameters in the gpr data inversion depends on the accuracy of the gpr external calibration in this research we studied the stability and the repeatability of two different gpr systems namely frequency and time domain systems a combination of a vector network analyzer and 800 5200 mhz horn antenna was used as a frequency domain gpr fd gpr whereas a gssi gpr system using a 900 mhz bowtie antenna was used as a time domain gpr td gpr both gpr systems including their antennas were calibrated several times using measurements with the antennas at different heights over a perfect electric conductor pec in the laboratory as well as over a water layer in addition measurements were performed over a thin water layer and a relatively thick sandy soil layer as validating medium the results showed that the fd gpr is relatively stable while the td gpr presents a significant drift which can be accounted for using corrections based on the air direct coupling waves free space measurements water and pec based calibrations provided very similar results for the gpr calibration functions inversions for the water layer and the sandy soil layer provided reliable results and showed a high degree of the repeatability for both radar systems the error on the calibration based on inaccurate antenna heights over pec showed the significant errors on the inversion results for the directive antenna horn antenna but less error for the bowtie antenna this analysis demonstrated the general validity of the proposed far field radar modeling approach not only with respect to frequency and time domain radars but as well with respect to the calibrating medium

world peat occurrence and the seasonality of climate and vegetation abstract the climatic controls on present day peat formation are examined in order to develop a uniformitarian tool for refining paleoclimate studies and to create a retrodictive model for the coals of the geologic record a peat database has been compiled for the world and the resulting patterns are compared with aspects of precipitation and temperature drawn from a gridded data set precipitation continuity through the annual cycle is important for biologic productivity in the terrestrial realm it is expressed in terms of the number of months with average precipitation above 40 mm temperature is limiting at higher latitudes where the potential growing season may be defined by the number of months with mean temperature exceeding 10 c a map predicting the growing season has been constructed from these rainfall and temperature statistics which compares very well with actual vegetation persistence through the year as measured directly from satellite instruments however biologic production will not result in peat accumulation unless groundwater levels are maintained through the growing season our peat prediction map therefore shows the percentage of time that precipitation occurs during the potential growing season present day peat accumulations are well predicted by this map

an abandoned channel fill with exquisitely preserved plants in redbeds of the clear fork formation texas usa an early permian water dependent habitat on the arid plains of pangea abstract a well preserved plant assemblage at the colwell creek pond locality of leonardian kungurian age provides an opportunity to evaluate taphonomic conditions in a dryland alluvial setting a narrow channel body incised to 5 m depth through red paleo vertisols contains 2 m of varicolored laminated mudstone with graded layers and plant material x ray diffraction analysis of individual laminae indicates the presence of chlorite illite kaolinite and mixed layer clay with hematite in red and gray layers and goethite in yellow brown laminae no carbonate was identified and the total organic carbon content is minimal the fine sediment accumulated in a shallow abandoned channel from suspension and gentle underflows probably linked to seasonal inflow and analysis of lamina thickness suggests that standing water may have persisted for up to a few millennia the preservation of lamination is attributed to a lack of bioturbation possibly linked to a paucity of subsurface oxygen low productivity elevated salinity rapid deposition or a combination of these factors minimal bioturbation may also reflect the limited use of freshwater ecospace during the early permian clay rich paleo vertisols complete the fill with drab root traces that indicate growth of vegetation in a strongly seasonal setting abundant plant material in the laminated beds includes branches of walchian conifers the possible cycadophyte taeniopteris spp and the comioid possible peltasperm auritifolia waggoneri they were derived from an adjacent riparian zone and preserved as 3d goethite petrifactions much of the foliage shows evidence of arthropod herbivory although a humid climatic episode cannot be ruled out the exceptional abundance and preservation of the plants probably reflects the persistence of an oxbow lake on a relatively arid alluvial plain where riparian plants experienced periodic moisture stress but had access to groundwater nearly year round rapid burial in standing water the lack of bioturbation in the laminated sediments and early biomineralization probably explain the exceptional preservation of the plant remains

the role of climate in stratigraphic patterns exhibited by late palaeozoic rocks exposed in kansas abstract late palaeozoic cyclothems of the midcontinental u s cannot be represented by a single ideal facies sequence rather they encompass a wide range of cycle types depending on their stratigraphic position the exposed late palaeozoic pennsylvanian and permian rocks of kansas as compiled by zeller 1968 can be divided into nine major lithofacies these lithofacies were ordered based on their times of greatest abundance through the section from oldest to youngest they attain their peak abundance in the following order 1 coal 2 gray mudrocks and sandstones 3 black mudrocks 4 limestones 5 cherty limestones 6 fossiliferous mudrocks 7 variegated mudrocks 8 evaporites and 9 variegated dolomitic siliciclastics climatically these nine lithofacies suggest a change from generally wetter at the base to generally drier at the top of the section this climatic trend was probably generated by a complex interaction of factors primarily driven by global tectonics climatic changes can be used to explain the five generally recognized types of lithofacies cyclothems in kansas and thus are a potential explanation for the changing stratigraphic patterns of the entire late palaeozoic time interval of kansas and perhaps elsewhere

formation and distribution of coal balls in the herrin coal pennsylvanian franklin county illinois basin usa large areas of concentrated coal balls permineralized peat up to 4 m thick obstructed longwall mining in the herrin coal at the old ben no 24 mine the largest coal ball area mapped contained 1500 m 3 several areas contained 400 m 3 of coal balls in mine mapping established that there were two types of roof freshwater and marine and that the coal balls were spatially correlated with the marine roof units regional studies and local data revealed that the younger freshwater energy shale mud originally covered all of the peat deposited at the mine but the mud was locally removed during a period of erosion the great majority of coal balls are found within the coal seam where they were permineralized in situ by carbonates some coal balls are found exposed on the eroded coal surface and others are within the channel fill associated with the erosion which predates any marine sedimentation thus the mineralization of the coal balls was synchronous with the erosion of the energy shale mud data from c and o isotope geochemical and mineralogical analyses of coal balls and associated materials were used to refine a depositional model of coal ball formation the concentrated coal ball areas were created by the triggered degassing of co 2 from partially decomposed peat in the presence of cations from fresh waters 13 c 12 c ratios in these coal balls average 23 9 13 c 12 c ratios as low as 34 occurring in the most concentrated coal balls are consistent with co 2 produced by anaerobic oxidation of methane top of seam coal balls were formed later and show slight to strong marine influence their 13 c 12 c ratios average 10 8

salinity contrast in the us midcontinent sea during pennsylvanian glacio eustatic highstands evidence from conodont apatite δ18o abstract pennsylvanian phosphatic black shales are widely interpreted to have been deposited in waters deep enough to produce a pycnocline that would have developed as a consequence of increased riverine runoff into the largely landlocked north american midcontinent sea during the more humid interglacial intervals of the late palaeozoic ice age we tested whether a gradient in surface water salinity existed in the north american midcontinent sea during times of maximum flooding by analyzing oxygen isotopes of conodont apatite from correlative pennsylvanian black shales of the midland midcontinent illinois and appalachian basins in the midland and midcontinent basins average 18 o values for conodonts from the oakley middle desmoinesian upper moscovian hushpuckney lower missourian lower kasimovian and heebner black shales lower virgilian lower gzehlian are 18 8 0 3 19 1 0 2 and 18 9 0 1 respectively oxygen isotope ratios of conodonts from the nuyaka creek black shale uppermost desmoinesian upper moscovian of the midcontinent basin are 19 8 0 3 and thus significantly higher in comparison to the other black shales these higher values support previous interpretations that the lost branch is a minor cyclothem with south polar regions having been less deglaciated than during the interglacial phases of the more widespread major cyclothems conodonts from oakley shale equivalents from ohio and pennsylvania are depleted in 18 o on average by 2 5 in comparison to conodonts from the midcontinent basin this pattern is also evident for conodonts from the heebner and hushpuckney shales although conodonts from the appalachian basin show only a 0 4 0 7 depletion in 18 o compared to conodonts from the midcontinent basin the differences in 18 o are interpreted as reflecting primarily salinity assuming that temperature was relatively constant across the palaeotropical midcontinent sea lower salinities in the appalachian basin and a significant salinity gradient in the midcontinent sea were reconstructed for the desmoinesian oakley shale supporting the idea that freshwater discharge resulted in a salinity stratified water column during times of everwet tropical palaeoclimate at least in the eastern part of the epeiric sea however the salinity gradient is considerably reduced during the subsequent missourian and virgilian periodically dry interglacial periods hushpuckney and heebner shales this suggests that surface waters in the midcontinent sea were not significantly influenced by continental runoff and calls into question whether a halocline was necessary for the formation of phosphatic core shales

sea level and environmental changes since the last interglacial in the gulf of carpentaria australia an overview abstract the gulf of carpentaria is an epicontinental sea maximum depth 70 m between australia and new guinea bordered to the east by torres strait currently 12 m deep and to the west by the arafura sill 53 m below present sea level throughout the quaternary during times of low sea level the gulf was separated from the open waters of the indian and pacific oceans forming lake carpentaria an isolation basin perched above contemporaneous sea level with outlet channels to the arafura sea a preliminary interpretation is presented of the palaeoenvironments recorded in six sediment cores collected by the images program in the gulf of carpentaria the longest core approx 15 m spans the past 130 ka and includes a record of sea level lake level changes with particular complexity between 80 and 40 ka when sea level repeatedly breached and withdrew from gulf lake carpentaria evidence from biotic remains foraminifers ostracods pollen sedimentology and geochemistry clearly identifies a final marine transgression at about 9 7 ka radiocarbon years before this transgression lake carpentaria was surrounded by grassland was near full and may have had a surface area approaching 600 km 300 km and a depth of about 15 m the earlier rise in sea level which accompanied the marine isotopic stage 6 5 transgression at about 130 ka is constrained by sedimentological and biotic evidence and dated by optical and thermoluminescence and amino acid racemisation methods

high resolution geochemistry and sequence stratigraphy of the hushpuckney shale swope formation eastern kansas implications for climato environmental dynamics of the late pennsylvanian midcontinent seaway abstract the hushpuckney shale member of the swope formation missourian stage eastern kansas is the core shale of a kansas type cyclothem formed during the late transgressive to early regressive phases of a late pennsylvanian glacio eustatic cycle coeval high frequency climato environmental dynamics of the midcontinent seaway are preserved in the kgs orville edmonds no 1a study core as centimeter scale variation in major components organic carbon authigenic sulfides and phosphate detrital siliciclastics organic macerals trace element redox proxies mo u v zn and ichnofabric features benthic o 2 levels declined sharply from the base of the black shale 0 cm went sulfidic at 4 cm and reached a redox minimum at 21 cm above this level redox potential gradually rose fluctuating between sulfidic and nonsulfidic conditions from 35 cm to the black shale gray shale contact at 52 cm onset of dysoxic conditions at that contact allowed establishment of a benthic community of soft bodied organisms comprised of deep tiered tracemakers tolerant of low o 2 conditions trichichnus and shallow tiered tracemakers favoring soupground helminthopsis or firmground substrates the zoophycos phycosiphon schaubcylindrichnus planolites association most geochemical records exhibit a low order cycle spanning the full 52 cm thickness of the black shale submember reflecting a dominant glacio eustatic control the base and top of the black shale submember record lateral migration of the pycnocline across the midcontinent shelf during the transgressive and regressive phases respectively the maximum flooding surface mfs is at 17 23 cm an interval containing the euxinic peak and characterized by high concentrations of illite representing a cratonic siliciclastic flux and terrestrial organic macerals the product of transient increases in humidity weathering rates and the export of coal swamp vegetation associated with the interglacial highstand of the swope cyclothem although a transgressive surface of maximum starvation sms cannot be confidently identified a phosphate rich regressive condensation surface at 28 34 cm records pycnoclinal weakening due to increased aridity associated with renewed southern hemisphere icesheet growth a correlative shift in dominance from terrestrial to marine derived organic macerals reflects increased upwelling of nutrient rich deepwaters and enhanced primary productivity penecontemporaneous paleogeographic and climatic factors e g semirestricted circulation monsoonal precipitation predisposed the midcontinent seaway toward sensitivity to high frequency climato environmental fluctuations which are preserved as 2 to 7 cm thick cycles in the study core the 52 cm thick black shale submember contains 12 such high order cycles which have an estimated average duration of 2 to 9 kyr implying a sub milankovitch band i e millennial scale climatic control the results of this study are relevant to the sequence stratigraphic interpretation of kansas type cyclothems the dynamics of gondwanan ice age glacio eustatic cycles and the development of boundary conditions for late pennsylvanian paleoclimate models

paleoclimate controls on stratigraphic repetition of chemical and siliciclastic rocks climate is a primary control on sediment flux from continental sources into sedimentary systems in warm climates siliciclastic input is greatest under highly seasonal rainfall nonseasonal conditions favor formation of end member chemical rocks perennially wet climates are conducive to coal formation whereas dry climates produce carbonates and or evaporites stratigraphic repetition of siliciclastic and chemical rocks therefore appears to be related to paleoclimate cycles as well as to transgressive regressive events and tectonics

palynologic petrographic and geochemical characteristics of the manchester coal bed in eastern kentucky the manchester coal bed in eastern kentucky is the stratigraphically lowest coal in kentucky that is both laterally continuous and of consistent mineable thickness the manchester coal bed occurs in the lower part of the breathitt formation in an interval between the underlying corbin sandstone and the overlying betsie shale both of which are also aerially widespread units the manchester is early middle pennsylvanian in age and is equivalent with the middle morrowan of the eastern interior basin and the late westphalian a of western europe increment samples were collected from the western and eastern outcrop and mining areas of the eastern kentucky coal field and were analyzed palynologically petrographically and geochemically to compare and contrast the two areas in the western part of the eastern kentucky coal field the manchester coal bed is uniform in occurrence and composition the bed is consistently 0 61 0 92 m 2 3 ft thick and generally is devoid of inorganic partings palynologically the coal in this area is largely dominated by lycospora the dispersed spore of many of the large lycopsid trees e g lepidodendron and lepidophloios and to a lesser extent granasporites medius representing diaphorodendron and synchysidendron petrographically the coal contains high percentages of vitrinite macerals and correspondingly low percentages of liptinite and inertinite macerals most of the increments from this area studied are generally low in ash yield 5 and sulfur content 10 and occasionally sulfur 1 in the eastern part of the coal field the manchester coal bed is typically thicker 3 ft 1 m but usually occurs as a coal zone with intercalated coal beds and clastic units palynologically the coal in this area contains increased percentages of small lycopsid small seed ferns calamites and cordaites petrographically the coal is higher overall in liptinite and inertinite macerals ash yields in the eastern sample area are generally low 10 an exception being some high ash durain bands overall sulfur contents also are low typically 1 the western samples are interpreted as having formed in a well protected generally flooded mire a consistent water cover would provide a favorable environment for arboreous lycopsid growth and proliferation and also inhibit oxidation of the peat surface thus promoting the formation of a high vitrinite content coal the eastern samples are also interpreted as having formed in a mire that was well protected most of the time giving rise to thick sequences of low ash low sulfur coal intermittent inundation by extra swamp waters carrying sediment in this area resulted in the development of a multiple coal zone i e several peat forming events with intervening clastic deposition in contrast to a single peat forming event in the western area surficial peat exposure was more frequent in the eastern area which allowed for increased microbial degradation of the peat and subsequent formation of inertinite macerals upon conversion to bituminous coal this condition might also accelerate charring of the peat surface by wildfire