lower and lower middle pennsylvanian fluvial to estuarine deposition central appalachian basin effects of eustasy tectonics and climate interpretations of pennsylvanian sedimentation and peat accumulation commonly use examples from the appalachian basin because of the excellent outcrops and large reserve of coal 100 billion metric tons in the region particularly controversial is the origin of lower and lower middle pennsylvanian quartzose sandstones beach barrier marine bar tidal strait and fluvial models all have been applied to a series of sand bodies along the western outcrop margin of the basin interpretations of these sandstones and their inferred lateral relationships are critical for understanding the relative degree of eustatic tectonic and climatic controls on early pennsylvanian sedimentation cross sections utilizing 1000 subsurface records and detailed sedimentological analysis of the livingston conglomerate rockcastle sandstone corbin sandstone and pine creek sandstone an informal member of the breathitt group were used to show that each of the principal quartzose sandstones on the margin of the central appalachian basin contains both fluvial and marginal marine facies the four sandstones are fluvially dominated and are inferred to represent successive bed load trunk systems of the appalachian foreland base level rise and an associated decrease in extra basinal sediment at the end of each fluvial episode led to the development of local estuaries and marine reworking of the tops of the sand belts each of the sand belts is capped locally by a coal regardless of whether the upper surfaces of the sand belts are of fluvial or estuarine origin suggesting allocyclic controls on deposition peats were controlled by a tropical ever wet climate which also influenced sandstone composition through weathering of stored sands in slowly aggrading braidplains recurrent stacking of thick coarse grained fluvial deposits with extra basinal quartz pebbles dominance of bed load fluvial lowstand deposits over mixed load estuarine transgressive deposits thinning of sand belts around tectonic highs and along faults cratonward shift and amalgamation of successive sand belts on the margin of the basin and truncation of successive sand belts toward the fault bound margin of the basin are interpreted as regional responses to alleghenian tectonism inferred to have been the dominant control on accommodation space and sediment flux in the early pennsylvanian basin

response of late carboniferous and early permian plant communities to climate change abstract late carboniferous and early permian strata record the transition from a cold interval in earth history characterized by the repeated periods of glaciation and deglaciation of the south

marine flooding events and coal bed sequence architecture in southern west virginia abstract eight regional lower to middle pennsylvanian coal beds namurian b c to westphalian c in southern west virginia were examined beds were divided into their component sedimentary parts or benches by identifying bounding surfaces and associated siliciclastic partings within beds bounding surfaces represent the cessation of peat accumulation paleo peat mire morphology at the bench level was determined using shape analysis petrographic indices and coal chemistry data planar and raised paleo peat mire benches were identified all gas coal and some splint coal benches were derived from raised mires heterolithic coal and the remaining splint coal benches were derived from planar mires most bounding surfaces are thin composed of oxidized and degraded organic materials high in ash and sulfur content and contain clay minerals and silt sized quartz vitrinite reflectance is suppressed in the upper part of some benches the associated siliciclastic parting materials when thick show evidence of tidal influence and contain brackish water to marine trace fossil assemblages bounding surfaces and the associated sediments represent a sudden increase in water depth and the lateral continuity of these surfaces indicates regional to basinal extent bounding surfaces are the up paleoslope expression of rapid

threshold of motion of coarse grained sediment under waves in shallow water this paper considers the threshold of motion of sediment in shallow coastal waters under breaking and non breaking waves a simple model representing conditions at the fluid sediment interface is developed the representation of a breaking wave is based on bore theory and the shear stress at the bed is based on the friction formula of o connor and yoo a threshold formula is presented based on the use of energy dissipation the threshold data is also related to the shields threshold criterion

climatic dependence of the organic matter contributions in the north eastern norwegian sea over the last 15 000 years abstract lipids are used for the evaluation of the different organic matter contributions in the north eastern norwegian sea m23258 site 75 n 14 e over the last 15 000 years development of a mass balance model based on the down core quantification of the c 37 alkenones the odd carbon numbered n alkanes a odd and the unresolved complex mixture of hydrocarbons ucm has allowed three main organic matter inputs involving marine continental and ancient reworked organic matter to be recognized the model shows good agreement between measured and reconstructed toc values similarly a strong parallelism is observed between predicted components such as marine toc and carbonate content which was determined independently representation of the model results within a time scale based on 15 ams 14 c measurements shows that the main changes in organic matter constituents are coincident with the major climatic events of the last 15 000 years thus the predominance of reworked organic matter is characteristic of termination ia up to 70 continental organic matter was dominant during the bolling allerod b a and younger dryas yd periods about 85 and a strong increase of marine organic matter occurred in the holocene between 50 and 75 this agreement reflects the main hydrographic changes that determined the deposition of sedimentary materials between 0 and 15 cal ka ice rafted detritus from the barents continental platform ice melting waters from the arctic fluvial system discharging into the barents sea and dominance of north atlantic currents respectively in this respect the high resolution down core record resulting from the mass balance and lipid measurements allows for the identification of millennial scale events such as the increase of reworked organic matter at the final retreat of the barents ice sheet at the end of the deglaciation period termination ib

a 20 ma pollen record of east asian summer monsoon evolution from guyuan ningxia china abstract pollen analysis was conducted on the fluviolacustrine sediments from the east side of the liupan mountains a relatively monsoon sensitive region and provided for the first time a continuous evolutionary history of vegetation and climate in east china during the neogene the pollen record spanning the last 20 ma indicates that the vegetation and thus east asian summer monsoon evolution can be divided into three stages 20 13 14 25 ma 14 25 11 35 ma and 11 35 0 08 ma in spite of general dominance of steppe throughout the neogene during the period 20 13 14 25 ma the pollen assemblage was characterized by high abundance of artemisia and small amounts of temperate to subtropical deciduous broad leafed trees such as juglans carya quercus and betula suggesting that the east asian summer monsoon was generally strong the interval from 14 25 to 11 35 ma was marked by a significant decline in the east asian summer monsoon as indicated by artemisia gradually replaced by humulus and halophytic chenopodiaceae nitraria and ephedra also reached high values in this period since 11 35 ma ago percentages of halophytes dominated by chenopodiaceae and tamaricaceae maintained a high mean value of about 40 revealing a weak intensity of east asian summer monsoon the general weakening of the monsoon circulation during the neogene and the significant monsoon decline during the late middle miocene in particular might link with the global cooling trend probably through two mechanisms cooling and ice sheet expansion over the polar region caused an increase in meridional temperature gradients leading to the southward retreat of the monsoon circulation the global cooling may have also reduced the amount of water vapor held in the atmosphere and led to both additional cooling and further weakening of the east asian summer monsoon the cause for a short lived resumption during the period 1 0 0 8 ma is under investigation

semi empirical treatment of wave transformation outside and inside the breaker line a semi empirical method is developed which predicts the wave height shoaling up to the break point on laboratory and natural beaches linear shoaling is enhanced with empirical curves for the wave shape obtained from field measurements of wave height through the break point and the surf zone made on an ocean beach in southern australia from 1987 to 1989 wave height shoaling breaking and attenuation are unified in a mixed lagrangian eulerian numerical model of random wave height transformation which with the semi analytical enhancements provides improved predictions of the height transformation of individual waves through the surf zone this is demonstrated for a wide variety of cases from the field and laboratory

paleopedology and geochemistry of late mississippian chesterian pennington formation paleosols at pound gap kentucky usa implications for high frequency climate variations abstract climate during the late mississippian late chesterian in the southern appalachian basin was characterized by alternating periods of aridity and humidity pennington formation paleosols at pound gap record climate and ecological changes for latest chesterian time ending at the mississippian pennsylvanian systemic boundary forty paleosols were identified described and assigned to seven pedotypes inferred soil orders considered as analogs include histosols entisols inceptisols alfisols and oxisols but are dominated by vertisols classification of an oxisol was determined by field and geochemical evidence of intense leaching and kaolinite dominated clay mineralogy field and micromorphologicial evidence suggests a polygenetic character of the vertisols resulting from changing soil drainage through time variations in soil drainage are quantified using proxy estimates of inferred soil processes such as base loss leaching lessivage and oxidation using the cia k proxy mean annual precipitation map estimates range from 519 to 1361 mm yr changes in map correspond with variation in inferred soil processes the flora of this time period in response to variations in precipitation and soil drainage also changes through time as evidenced by changes in abundance and depth of root traces reconstructed ecosystems range from sparse vegetative cover with shallow tabular root systems in early pennington soil development to dense deeply penetrating root systems suggestive of arborescent floral associations at the top of the succession approaching the mississippian pennsylvanian boundary this study provides greater resolution of changing climate and pedogenic processes than what is provided in previous studies of late mississippian climate and suggests that the documented variability in paleosol types and soil drainage might represent the record of high frequency climate changes likely associated with expansion and contraction of the paleo intertropical convergence zone itcz

comparison of the eastern and western kentucky coal fields pennsylvanian usa why are coal distribution patterns and sulfur contents so different in these coal fields abstract more than 130 mt of pennsylvanian coal is produced annually from two coal fields in kentucky the western kentucky coal field occurs in part of the illinois basin an intercratonic basin and the eastern kentucky coal field occurs in the central appalachian basin a foreland basin the basins are only separated by 140 km but mined western kentucky coal beds exhibit significantly higher sulfur values than eastern kentucky coals higher sulfur coal beds in western kentucky have generally been inferred to be caused by more marine influences than for eastern kentucky coals comparison of strata in the two coal fields shows that more strata and more coal beds accumulated in the eastern than western kentucky coal field in the early and middle pennsylvanian inferred to represent greater generation of tectonic accommodation in the foreland basin eastern kentucky coal beds exhibit a greater tendency toward splitting and occurring in zones than time equivalent western kentucky coal beds which is also inferred to represent foreland accommodation influences overprinted by autogenic sedimentation effects western kentucky coal beds exhibit higher sulfur values than their eastern counterparts but western kentucky coals occurring in langsettian through bolsovian strata can be low in sulfur content eastern kentucky coal beds may increase in sulfur content beneath marine zones but generally are still lower in sulfur than mined western kentucky coal beds indicating that controls other than purely marine influences must have influenced coal quality the bulk of production in the eastern kentucky coal field is from duckmantian and bolsovian coal beds whereas production in the western kentucky coal field is from westphalian d coals langsettian through bolsovian paleoclimates in eastern kentucky were favorable for peat doming so numerous low sulfur coals accumulated these coals tend to occur in zones and are prone to lateral splitting because of foreland tectonic and sedimentation influences in contrast westphalian d coal beds of western kentucky accumulated during low differential tectonic accommodation and therefore tend to be widespread and uniform in characteristics but exhibit higher sulfur values because they accumulated in seasonally drier paleoclimates that were unfavorable for peat doming hence basin analyses indicate that many differences between the mined coals of kentucky s two coal fields are related to temporal changes in paleoclimate and tectonic accommodation rather than solely being a function of marine influences

evaluating trace elements as paleoclimate indicators multivariate statistical analysis of late mississippian pennington formation paleosols kentucky u s a abstract the temporal and spatial distributions of trace elements in paleosols in relation to soil forming processes and climate have received little attention primarily due to their generally low concentrations 100 ppm and a fundamental lack of knowledge of their behavior in soil systems trace element concentrations of pennington formation paleosols spanning an 8 ma interval in the late mississippian chesterian were analyzed using linear and multivariate statistics of whole rock elemental data linear statistics of the elemental data set show that ti zr nb cs la hf ta w ce and th have the highest correlation through time with r values 0 75 nb served as the proxy trace element for comparison temporal trends in nb closely match trends in lessivage clay formation and accumulation by feldspar weathering mean annual precipitation map and chemical weathering map effectively controls soil hydrology and the accumulation of organic matter and clay map in conjunction with chemical we

organic carbon distribution in the north atlantic ocean during the last glacial maximum abstract the organic carbon content of eighty two last glacial maximum lgm sediment samples from the north atlantic ocean was determined with a coulometer organic carbon in these sediments averaged about 0 5 by weight slightly higher than in modern sediments factors that control organic carbon distribution were examined in two ways by mapping the spatial distribution of organic carbon during the lgm and by comparing organic carbon content to sediment characteristics in general sediment organic content increases with increasing sedimentation rate increasing clay content and decreasing carbonate content the spatial distribution of lgm organic content is similar in most respects to the mapped modern distribution the primary exception being areas of high organic content one area of high organic content off nortwest africa is situated in the same area geographically but is larger than its modern counterpart perhaps indicating that wind driven upwelling was more intense and or widespread during the lgm the two other areas of high organic carbon content the north american margin and west of the mid atlantic ridge mar at about 40 n have no modern counterpart on the north american margin south of cape cod organic carbon content is generally 0 6 and in several samples is 0 9 the increased organic carbon content of sediment in this area appears to be related to an increase in sedimentation rate and the concomitant increase in inorganic nutrients the area west of the mar is more perplexing and appears to be related to changes in lgm surface circulation

burial rates of organic matter along the eastern canadian margin and stable isotope constraints on its origin and diagenetic evolution abstract organic carbon oc and nitrogen n contents and 13 c and 15 n values in total organic matter om were measured in sub surface sediments 0 30 cm sub bottom from 21 cores raised from the laurentian channel of the gulf of st lawrence and the labrador sea to document om fluxes and storage along the eastern canadian margin storage rates as high as 2 5 g m 2 yr 1 for oc and 0 2 g m 2 yr 1 for n are observed in the laurentian channel suggesting that the shelf plays a significant role in terms of om storage from 1 to 2 of the primary production based on the isotopic composition of the essentially marine om of the labrador sea 13 c v pdb 21 9 0 4 15 n air 7 6 0 6 n 12 there is no isotopic evidence for a significant relative input of terrestrial om along the laurentian channel 13 c v pdb 21 9 0 4 15 n air 8 0 0 9 n 10 either due to high relative fluxes of marine om and or to the trapping of continental om in the estuary and upstream high storage rates of om are also observed on the continental rise of the labrador sea as high as 1 1 g c m 2 yr 1 and 0 09 g n m 2 yr 1 they contrast with one order of magnitude lower rates on the slope due to low sedimentation rates sr and sediment winnowing by the western boundary undercurrent wbuc reduced early diagenetic alteration of om is observed particularly in the laurentian channel it results in discrete i losses of oc and n ii shifts in c n ratios suggesting preferential removal of n bearing om also highlighted by losses in total hydrolysable amino acids haa in the labrador sea slope records due to low sr om concentration changes linked to long term temporal variations may superimpose on these diagenetic trends and some influence of the wbuc is noticeable

the ichnogenus rhizocorallium classification trace makers palaeoenvironments and evolution rhizocorallium is one of the oldest known trace fossils with wide distribution through the phanerozoic and all over the world originally introduced from the epicontinental triassic of central germany its high morphological lability gave reason for the subsequent erection of about twenty ichnospecies the study of newly collected material from the type area and many specimens from various collections permits the conclusion that rhizocorallium jenense and rhizocorallium commune are the only valid ichnospecies of rhizocorallium the type ichnospecies r jenense is a comparatively small inclined and heavily scratched firmground burrow with passive fill while r commune consists of extensive more or less horizontal burrows with occasionally scratched marginal tubes and an actively filled spreite between the tubes the faecal pellets coprulus oblongus are typically associated with r commune morphological variations of r commune are captured in ichnosubspecies and varieties of this ichnospecies and can aid a refined reconstruction of palaeoenvironments a review of more than 180 records from the literature reveals the common confusion of both ichnospecies which has consequences for the application of rhizocorallium in facies interpretations the end members of both ichnospecies may be linked by transitional forms which suggests the same kind of trace maker polychaetes are the most likely producers of marine rhizocorallium based on their long ranging occurrence morphological features appearance of faecal pellets associated soft body remains and modern analogues r commune occurs from early cambrian to holocene while r jenense just appears after the end permian mass extinction probably as a consequence of an adapted firmground burrowing lifestyle of its producer fluvial r jenense are probably produced by mayfly larvae in homology to marine polychaete burrows a consequent application of the newly established classification scheme allows for a more rigorous application of rhizocorallium in the reconstruction of palaeoenvironments thus palaeozoic and mesozoic r commune are restricted to the cruziana ichnofacies of shallow marine environments while in cenozoic time similar forms are also found in deep marine deposits r jenense on the other hand is a constituent of the widespread glossifungites ichnofacies and aside from continental environments occurs in peritidal to deep marine deposits several studies have demonstrated the value of rhizocorallium for interpreting sequence stratigraphical surfaces current directions and fluctuations in salinity and oxygen

depositional environment and source rock potential of miocene strata from the central fram strait introduction of a new computing tool for simulating organic facies variations abstract organic rich sediments were recognized in early miocene strata from the norwegian greenland sea during odp leg 151 three organic geochemical subunits were distinguished in hole 909c using detailed organic geochemical and microscopic analyses toc up to 3 wt hi up to 200 mg hc g toc and 13corg values 24 26 indicate the predominance of terrestrial type iii organic matter in subunit 3 18 16 2 ma biomarker and vitrinite reflectance values r0 0 5 point to rather fresh immature terrestrial organic matter supplied by river discharge from adjacent vegetated coastal areas although the sediments of subunit 3 have a fair to good source rock potential they are insufficiently mature to generate significant amounts of oil or gas to test if the moderate generation potential and source rock quality of subunit 3 are applicable to the entire area the computer software of mod was applied several modelling runs testing the most probable depositional scenarios result even under conservative assumptions in the formation of good to excellent source rocks towards the basin margins

pennsylvanian continental cyclothem development no evidence of direct climatic control in the upper freeport formation allegheny group of pennsylvania northern appalachian basin abstract the occurrence of lacustrine carbonates in the allegheny group upper middle pennsylvanian continental cyclothems of the northern appalachian basin has been attributed to climatic alternation of wet coal deposition and dry carbonate deposition periods however we present evidence from facies associations coal and carbonate petrography and carbonate stable isotope geochemistry for a uniformly wet climate throughout deposition of one of the earliest continental cyclothems the upper freeport formation uff we propose a depositional model comprising a large wetland complex drained by an anastomosed fluvial system containing a mosaic of channels freshwater siliciclastic and carbonate lakes and peat bogs swamps on a siliciclastic floodplain carbonate phases represent bio induced precipitates modified by lake dynamics and not evaporative deposits absence of covariant isotopic trends between 18o and 13c and a relatively small range of 18o values 1 9 to 6 4 pdb that are close to or lighter than predicted paleoprecipitation for the pennsylvanian equatorial regions indicate hydrologically open short residence time lake systems in support of our sedimentary model combined sedimentologic and isotopic data do not indicate reduced effective moisture precipitation evaporation during intervals of limestone deposition the uff lakes developed in a relatively wet climate zone without significant episodic closure due to climatically induced water deficit lithologic patterns within the uff cyclothem are primarily attributed to the evolution of anastomosed fluvial systems controlled by subsidence in an active foreland basin rather than to short term climatic change or eustacy

climatic depositional and burial controls on diagenesis of appalachian carboniferous sandstones qualitative and quantitative methods abstract carboniferous quartz lithic and feldspar rich sandstones from different stratigraphic intervals within the central appalachian basin contain evidence for eogenetic and mesogenetic diagenesis important eogenetic products include fe oxide oxyhydroxide siderite kaolinite chlorite and calcite whereas quartz albite illite sericite fe carbonate and secondary porosity are the most important mesogenetic components correspondence and detrended correspondence analysis of the framework grain and diagenetic mineral data set has guided diagenetic interpretations and leads to two major conclusions first minerals that formed early appear to have been influenced by stratigraphic position the distribution of siderite and iron oxide oxyhydroxide is considered to reflect a second order paleoclimatic signature recognized throughout the carboniferous where siderite formed during everwet periods and iron oxide oxyhydroxide during semi arid conditions reflecting differences in redox second framework grain composition controlled the distribution of diagenetic products in the burial environment lithic arenites are deficient in authigenic quartz yet have undergone various degrees of illitization quartz deficiency is attributed to compaction related loss of primary porosity relatively early which inhibited sufficient fluid flow to account for much higher concentrations of quartz cement in the more competent quartz rich sandstones

mean bed friction of combined wave current flow abstract bijker s model for evaluating the wave period mean bed friction of combined wave current flow has been modified to account for the current velocity reduction as well as the wave boundary layer near the sea bed a method of estimating the bed frictional dissipation rate of the combined flow is also presented the results obtained by the present approach are compared with several sets of experimental data and confirm its accuracy and usefulness

sequence stratigraphic expression of greenhouse transitional and icehouse conditions in siliciclastic successions paleozoic examples from the central appalachian basin usa abstract climates during the paleozoic varied from greenhouse to transitional to icehouse and siliciclastic successions deposited during those times have stratigraphic architectures consistent with magnitudes and frequencies of sea level fluctuations at the time of deposition three central appalachian basin paleozoic successions the early cambrian chilhowee group the late devonian foreknobs formation and the early pennsylvanian breathitt group are compared and contrasted to develop models that relate stratigraphic architectures to greenhouse transitional and icehouse conditions existing on earth within the upper portion of the early cambrian chilhowee group the hampton and erwin formations represent a succession of 2 myr 3rd order sequences consisting of stacked 40 80 kyr 5th order marine parasequences that record low magnitude high frequency sea level changes consistent with greenhouse conditions the late devonian foreknobs formation consists of a series of 0 8 1 0 myr 3rd order composite sequences comprised of stacked unconformity bounded 225 to 450 kyr 4th order sequences each containing 40 to 65 kyr 5th order marine parasequences the bases of the unconformity bounded sequences are marked by erosional surfaces regressive surfaces of marine erosion fluvial deposits or paleosols indicative of sea level drops of 10 to 45 m consistent with a transitional greenhouse to icehouse climate the early pennsylvanian breathitt group consists of stacked unconformity bounded 100 kyr 4th order sequences that lack parasequences unconformity bounded sequences are comprised of from bottom to top lowstand incised valley braided alluvial deposits transgressive tidal estuarine deposits and progradational highstand deltaic deposits depths of incised valleys and vertical transition into estuarine facies imply sea level changes of 50 m consistent with icehouse conditions this study demonstrates that siliciclastic successions preserve a record of sea level changes consistent with greenhouse transitional and icehouse conditions on the paleozoic earth

a virtual power function for estimating the alongshore transport of sediment by waves abstract a transport formula is presented which is based upon the rate of energy dissipation in breaking waves it incorporates a dimensionless grain size parameter and has been calibrated against field and laboratory data

the use of field analogues in the correlation and static reservoir methodology used in the tern field northern north sea uk three dimensional modelling of reservoirs deposited in different depositional environments suggests that they require different correlation methodologies an example drawn from the tern field located in the brent province in the northern north sea offshore uk shows that the rannoch formation interpreted from core as a shoreface deposit can successfully be correlated using a sequence stratigraphic framework constrained by flooding surfaces in contrast the younger lower ness formation interpreted as dominantly coastal plain in character also required a sequence stratigraphic approach but one based upon broader depositional cycles in the latter correlation it was important not to correlate isolated sandbodies within the channel belts which would have led to an overestimation of reservoir volumes field analogues from the book cliffs of utah and breathitt group of kentucky support the concepts behind the contrasting approaches to correlation while not necessarily providing precise depositional analogues the interpolation of reservoir properties in the tern field reservoir model demonstrates that the correlation strategy is robust and provides evidence of a northwesterly progradation direction within the rannoch formation of the tern field

coalescent valley fills from the late quaternary record of tuscany italy abstract three prominent incised valley fills of post last glacial maximum age are described from the northern tuscan coast of italy stratigraphic correlation of core data along a cross section transversal to the present fluvial channel axes enables identification of a suite of genetically related valley bodies that fill the incisions made up by arno serchio and camaiore stiava rivers during the last glacial interglacial cycle the valley fills display different shapes and size but remarkably similar facies architecture valley bodies range between 5 and 10 km in width and between 30 and 45 m in thickness with width thickness ratios of about 100 300 above a lowstand and early transgressive gravel fluvial deposit the three incised valley fills display a distinctive succession of coastal plain to estuarine facies dated to about 13 8 cal ka bp radiocarbon dates document that the three valleys were active simultaneously accommodation space was rapidly created during transgression and then filled under conditions of very high sediment accumulation about 1 cm y in contrast to the more common deepening upward trend recorded by the latest pleistocene early holocene valley fill successions worldwide sedimentation in the tuscan valleys equalled or even exceeded the rate at which accommodation was created thus leading to an aggradational rather than backstepping stacking pattern of high frequency millennial scale parasequences above the valley fills and on the interfluves a thin deepening upward succession of nearshore deposits marks the rapid change from aggradational to retrogradational depositional style this is invariably overlain by a characteristic shallowing upward motif of prograding deltaic and coastal facies the maximum flooding surface which can be tracked across the whole study area on the basis of subtle palaeontologic indicators is shown to represent an almost isochronous surface dated to about 7 8 cal ka bp through examination of large scale geometry and facies attributes of the valley fills including the relationships between valley bodies and interfluves this study represents an example of how adjacent river systems with significantly different characteristics may respond simultaneously in a consistent manner to rapid changes in sea level and climate conditions

upstream controls on incised valley dimensions and fill examples from the upper mississippian mauch chunk group central appalachian basin usa abstract subsurface mapping and facies and architectural element analysis on outcrop combined with published detrital zircon geochronology and sandstone petrography are used to reconstruct a source to sink system for two incised valley fills in the upper mississippian mauch chunk group the lower stony gap incised valley is relatively broad and filled with quartzarenite fluvial facies consisting of downstream accreting elements with minimum thicknesses of 6 m cross sets within elements average 62 5 cm thick the lower princeton incised valley is relatively narrow and filled with sublitharenite fluvial facies consisting of channel elements that range in thickness from 0 25 to 3 6 m cross sets within elements average 35 cm thick quantitative estimates of drainage areas using regional hydraulic geometry curves for comparable climatic settings are consistent with order of magnitude differences for the lower stony gap sandstone 700 000 km2 and the lower princeton formation

radiometric dating of marine influenced coal using re os geochronology abstract coal deposits are integral to understanding the structural evolution and thermal history of sedimentary basins and correlating contemporeous estuarine and fluvial delatic strata with marine sections while marine shales may readily lend themselves to re os dating due to the dominance of hydrogenous re and os the lack of a chronometer for near shore sedimentary environments hampers basinwide correlations in absolute time here we employ the re os geochronometer along with total organic carbon toc and rock eval data to determine the timing and conditions of a marine incursion at the top of the matewan coal bed kanawha formation pottsville group west virginia usa the observed range for hydrogen index hi 267 290 mg hydrocarbon gram total organic carbon for these coal samples suggests dominance of aliphatic hydrocarbons with low carbon 107 6 16 4 ng g and os 0 52 0 09 ng g concentrations of the marine influenced matewan coal are higher by few orders of magnitude than published data for terrestrial coal a re os isochron for the matewan coal provides an age of 325 14 ma model 3 mswd 12 n 19 2 this is the first re os age derived from coal samples the age overlaps a new composite re os age of 317 2 ma for the immediately overlying betsie shale member external precision for replicate os analyses carried out for several matewan coal samples shows a positive correlation with their hi the hi which is low in terrestrial organic matter reflects the degree of marine influence thus samples with the most profound marine influence also have the best analytical reproducibility equilibration of os isotopes with seawater under marine conditions overwhelms variability inherited from terrestrial plant debris decreasing scatter on the isochron the 187re 188os ratios of the matewan coal 3300 5135 are higher than most of those previously published for phanerozoic black shale mostly

why terrestrial coals cannot be dated using the re os geochronometer evidence from the finnmark platform southern barents sea and the fire clay coal horizon central appalachian basin abstract coal horizons in terrestrial sedimentary sections are key to understanding the structural and thermal evolution of sedimentary basins precise and accurate age information for coal horizons can define correlations and the temporal evolution of sedimentary successions while the biostratigraphy for coal horizons yields relative ages tied to radiometric ages through the continuously refined geological time scale direct radiometric ages of coal horizons have been derived only from tonsteins lithified ash beds the re os geochronometer has been proven to record accurate and precise depositional ages for sedimentary rocks rich in organic matter however the reliability of the re os geochronometer has not yet been assessed for coals deposited in strictly terrestrial environments here in order to test the re os geochronometer we measure the re os concentrations and isotopic composition of terrestrial coals from two distinct environments the finnmark platform southern barents sea and the central appalachian basin cab samples from the finnmark platform soldogg formation also include an adjacent organic rich shale horizon the shale and two coal horizons were also analysed for total organic carbon toc and rock eval data results show that the soldogg coals and shale reached the oil generation widow tmax 448 2 c with type iii or mixed type ii iii organic matter supporting the model for deposition in overbank deposits in a fluvial setting in contrast the fire clay coals in the cab were deposited in a broad expanse of mires average re 0 5 0 4 ng g and os 23 26 pg g concentrations of terrestrial soldogg and fire clay coals are similar to those of terrestrial maghara coal and a few orders of magnitude lower than the marine influenced matewan coal elevated re os ratio os common os os corrected for ingrowth of 187os since deposition of the sample for the fire clay coals suggests highly reducing and or euxinic conditions prevailing in the water column of the extensive carboniferous peat forming mire in which these coals were deposited in contrast lower re os for soldogg coals highlight less reducing conditions likely in a short lived mire in a dynamic braided stream system re and os concentrations of terrestrial coals are on the order of re and os of plant materials and river sediments suggesting that debris from plant materials and weathered continental crust are significant contributors of re and os to terrestrial coals with some contribution from water column of the coal mire this study is the first attempt to apply the re os geochronometer on terrestrial coals in case of the soldogg coals and shale the 187re 188os vs 187os 188os relationship displays scatter with no discernible linear trend the scatter is ascribed to heterogeneity in the initial 187os 188os ratios osi and lack of post depositional isotopic equilibration during subsequent diagenesis for the fire clay coals 187os 188os and 187re 188os are well correlated linear regression of the data however does not yield a geologically reasonable age rather the linear relationship results from binary mixing between two end members the fire clay coal and tonstein suggesting that re os systematics of terrestrial coals depositing very close to tonstein beds can be significantly disturbed we conclude that the post depositional equilibration with a large re os reservoir as with a marine incursion is necessary to record a meaningful re os radiometric age for the coals

the sedimentary record of carboniferous rivers continuing influence of land plant evolution on alluvial processes and palaeozoic ecosystems abstract evidence from modern rivers and the deep time geological record attests to the fundamental importance of plant life for the construction of physical habitats within fluvial environments data from an extensive literature review and original fieldwork demonstrates that many landforms and geomorphic features of modern river systems appear in the palaeozoic stratigraphic record once terrestrial vegetation had adopted certain evolutionary advances for example stable point bars are associated with the onset of rooted plants in the siluro devonian and avulsive and anabranching fluvial systems become common at the same time as extensive arborescent vegetation in the carboniferous in this paper we demonstrate a correlation between the diversification of physical fluvial environments and the expansion of terrestrial fauna and flora with an emphasis on the culmination of these trends within carboniferous alluvial systems many extrinsic factors have been considered as possible controls on the evolutionary timelines of terrestrialization for organisms however a fundamental prerequisite for achieving terrestrial biodiversity was the variety of physical habitats especially riparian systems available for newly evolved organisms in association with abundant lowland meandering systems the widespread appearance across carboniferous alluvial plains of fixed channel and anabranching reaches created further physical landforms for colonization and would have promoted increasingly complex hyporheic flow regimes furthermore the associated increase in arborescent vegetation and supply of large woody debris to inland and coastal rivers would have created a wealth of microhabitats for continental organisms we argue that the expanding extent and diversity of physical alluvial niches during the palaeozoic is an underappreciated driver of the terrestrialization of early continental life the study of the deep time fossil and stratigraphic record also illustrates that vegetation is a fundamental prerequisite for the creation of biogeomorphic alluvial landforms and physical habitats and microhabitats

geomorphic and sedimentary response of rivers to tectonic deformation a brief review and critique of a tool for recognizing subtle epeirogenic deformation in modern and ancient settings abstract rivers are extremely sensitive to subtle changes in their grade caused by tectonic tilting as such recognition of tectonic tilting effects on rivers and their resultant sediments can be a useful tool for identifying the often cryptic warping associated with incipient and smaller scale epeirogenic deformation in both modern and ancient settings tectonic warping may result in either longitudinal parallel to floodplain orientation or lateral normal to floodplain orientation tilting of alluvial river profiles alluvial rivers may respond to deformation of longitudinal profile by 1 deflection around zones of uplift and into zones of subsidence 2 aggradation in backtilted and degradation in foretilted reaches 3 compensation of slope alteration by shifts in channel pattern 4 increase in frequency of overbank flooding for foretilted and decrease for backtilted reaches and 5 increased bedload grain size in foretilted reaches and decreased bedload grain size in backtilted reaches lateral tilting causes down tilt avulsion of streams where tilt rates are high and steady down tilt migration combing where tilt rates are lower each of the above effects may have profound impacts on lithofacies geometry and distribution that may potentially be preserved in the rock record fluvial sedimentary evidence for past tilting is traditionally based on the assumption that depositional features reminiscent of modern fluvial tectonic effects are evidence for past tectonic effects where it is closely associated with historically active structures or where non tectonic causes cannot be invoked however caution must be exercised when using these effects as criteria for past or current tectonic warping as these effects may be caused by non tectonic factors these non tectonic causes must be eliminated before tectonic interpretations are made

chemical diagenetic constraints on the timing of cataclasis in deformed sandstone along the pine mountain overthrust eastern kentucky abstract cathodoluminescence imaging reveals that sandstones of the middle pennsylvanian lee formation and breathitt group along the pine mountain overthrust pmo contain inter and intra granular authigenic quartz in proportions that differ markedly between samples of contrasting deformational state fracture surfaces generated during fault movement provided nucleation substrates favorable for the emplacement of substantial amounts of intragranular quartz up to 11 volume percent in the lee formation relatively undeformed sandstones contain cement that is dominantly intergranular whereas sandstones from highly deformed cataclasites along the trace of the pmo contain cement that is dominantly localized within intragranular fractures therefore the chemical diagenetic histories of different samples of breathitt and lee sandstones diverged markedly as a consequence of differing deformational histories and the cementation history thus constitutes a record that is relevant to deciphering the timing of deformation the small quantities of early formed intergranular cement within the cataclasites average 3 7 volume percent show evidence of breakage and accordingly must have largely pre dated the deformation quartz cementation modeling touchstone suggests that emplacement of this pre deformational intergranular cement within these deformed rocks can be bracketed within a period from approximately 280 to 260 ma an interpretation of fault movement that shortly post dates this initial period of quartz cementation is consistent with other estimates for the timing of the alleghanian orogeny because of their protracted period of burial rocks in the vicinity of the pmo remained at temperatures amenable to continued quartz cementation until the middle cenozoic and thus most of the quartz cementation in the cataclasites and also in the surrounding undeformed sandstones post dates movement on the fault

peat accumulation on a drowned coastal braidplain the mullins coal upper carboniferous sydney basin nova scotia abstract the mullins coal lies within the braided fluvial south bar formation the lateral extent 15 km and thickness 2 m of the coal suggest that controls for peat accumulation were allogenic marine inundation of the distal braidplain as indicated by the high sulphur content of the coal and the occurrence of agglutinated foraminifera in associated shales caused ponding of freshwater near maximum marine transgression with accumulation of thick paralic peat across a stable platform of sandy fluvial sediments highstand parasequences with thin capping coals were subsequently incised beneath a sequence boundary as the braidplain readvanced the mullins coal thins and splits in association with muddy bayfill deposits eastward towards the glace bay syncline a long lived palaeotopographic element related to fault bounded basement blocks although relative sea level change controlled the stratigraphic position of the precursor peats differential tectonic subsidence and or compaction modified their extent thickness and quality

compound paleovalley fills in the lower pennsylvanian new river formation west virginia usa abstract ancient paleovalley fills are typically interpreted in the rock record using over generalized models without carefully considering modern analogs especially in light of recent discoveries it is now known that many quaternary paleovalleys are compound in origin exhibit considerable stratigraphic complexity contain multiple incisions and can be orders of magnitude larger than their putative ancient counterparts compound paleovalley fills in the lower pennsylvanian new river formation nrf are directly comparable to these quaternary analogs stimulating a paradigm shift in the interpretation of ancient paleovalleys in the nrf multiple laterally and vertically juxtaposed fill successions separated by incision surfaces record high frequency fluvial responses to external controls within lower order sequences lowstand incision and sediment bypass as predicted in sequence stratigraphy is largely discounted by the available evidence and the definition of regional sequence boundaries is not straightforward the identification of genetic sequences may be the most effective approach to understanding the nrf and by inference many other ancient paleovalleys results from this study of the nrf promote a revised model for ancient paleovalleys that incorporates 1 the pre eminence of compound architecture 2 periodic episodes of incision and subaerial exposure occurring in response to high frequency changes in climate or relative sea level 3 fluvial downcutting as the primary cause of paleovalley incision although some sediments are still preserved in a net erosional regime and 4 composite time transgressive sequence boundaries that may be difficult or impossible to correlate regionally

the magnitude of late paleozoic glacioeustatic fluctuations a synthesis a comprehensive literature review shows that the magnitude of eustatic fluctuations varied throughout the carboniferous and permian and that at least eight distinct phases can be recognized facies juxtapositions in carbonate successions and erosional relief in clastic successions indicate that glacioeustatic fluctuations of 20 25 m and occasionally as much as 60 m took place throughout the early mississippian tournaisian a widely recognized glacial period middle mississippian mid chadian through holkerian shallow marine carbonate and clastic successions indicate that eustatic fluctuations were 10 25 m a decrease that matches well with the paucity of coeval glacial deposits late visean asbian through mid brigantian glacioeustatic fluctuations of 10 50 m record the initial phases of ice accumulation in advance of the widespread mid carboniferous glacial event the latest mississippian earliest pennsylvanian mid brigantian through langsettian was a time of widespread glaciation and strata of this age commonly exhibit evidence of glacioeustatic fluctuations of as much as 40 100 m although middle pennsylvanian duckmantian through asturian glacial deposits are present in eastern australia paleovalley depths suggest that coeval glacioeustatic fluctuations were less than 40 m glacioeustatic fluctuations of as much as 100 120 m have been widely reported from late pennsylvanian earliest permian stephanian through mid sakmarian successions in north america an increase that corresponds to the growth of large ice sheets across much of gondwana and the accumulation of ice in the northern hemisphere incision and facies juxtaposition in early middle permian mid sakmarian through kungurian successions in eastern australia indicate that glacioeustatic fluctuations of 30 70 m occurred during the waning stages of major glaciation erosional relief in paleoequatorial carbonates and the presence of coeval glacial deposits in australia suggests that eustatic fluctuations of 10 60 m occurred during the final stages of glaciation in the middle to late permian roadian through capitanian but the modest size of most of these fluctuations makes it difficult to isolate the glacioeustatic signature this review demonstrates that far field cyclic successions record changing glacial conditions in gondwana that the magnitude of glacioeustatic fluctuations was directly related to the volume of glacial ice that carboniferous permian glacioeustasy was more variable than previously recognized and that generalizations from short temporal intervals are probably not representative of the late paleozoic ice age as a whole although any attempt to quantify the magnitude of ancient eustatic changes is based on caveats and assumptions this review incorporates the results of over 100 published papers on the topic in an attempt to minimize the errors inherent in any one study

sequence stratigraphic hierarchy of the upper devonian foreknobs formation central appalachian basin usa evidence for transitional greenhouse to icehouse conditions abstract the foreknobs formation upper devonian upper frasnian to basal famennian comprises the uppermost marine strata of the progradational catskill clastic wedge of the south central appalachian mountains virginia west virginia usa the foreknobs formation consists of 14 lithofacies arranged in four facies associations which record the following depositional settings 1 storm dominated distal to proximal offshore to shoreface facies association a 2 sharp based conglomeratic shoreface facies association b 3 fluvial redbed facies association c and 4 incised valley fill ivf facies association d vertical juxtaposition and stacking patterns of lithofacies and facies associations permit recognition of a hierarchy of three scales of cyclicity up to 70 short term 5th order cycles each averaging 65 kyr consist of coarsening upward parasequences of storm dominated offshore marine facies in the distal setting which correspond to high frequency unconformity bound sequences hfs of fluvial redbed strata overlain by offshore marine strata in the proximal setting these facies relationships are a consequence of 10 15 m of sea level fluctuations up to 12 intermediate term 4th order cycles each averaging 375 kyr consist of stacked 5th order cycles the 4th order cycles are bounded by regressive surfaces of marine erosion rsme at the base of sharp based conglomeratic shoreface sandstones in the distal setting that correspond with paleosols in the proximal setting in some cases the 5th order cycles within each 4th order cycle exhibit stacking patterns indicative of increasing or decreasing accommodation space these facies relationships are a consequence of 25 35 m of sea level fluctuations three complete and portions of two additional 3rd order cycles each averaging 1 12 myr consist of stacked 4th order cycles the 3rd order sea level trends reflected in the foreknobs formation are nearly identical to published eustatic sea level curves incised valley fills are present at one of the 3rd order cycle boundaries and are a consequence of a 35 45 m sea level fluctuation the amplitudes of the inferred sea level fluctuations are comparable to the expansion and contraction of ice volumes within the current greenland and antarctic ice sheets which suggests glacioeustasy was the primary control on sea level fluctuations and cyclicity within the foreknobs formation such an interpretation is consistent with knowledge of devonian climate transitioning from middle devonian greenhouse to late devonian icehouse as indicated by evidence of glaciation during parts of the late devonian in south america and the appalachians

organic carbon accumulation in baffin bay and paleoenvironment in high northern latitudes during the past 20 m y the results of the investigation of organic carbon deposition in baffin bay provide important information about paleoenvironmental evolution in high northern latitudes during cenozoic time during miocene to quaternary time organic carbon enrichment of up to 3 insediments sampled at ocean drilling program site 645 was controlled mainly by increased supply of terrigenous organic matter two distinct maxima were identified 1 a middle miocene maximum possibly reflecting a dense vegetation cover and fluvial sediment supply from adjacent islands which decreased during late miocene and early pliocene time because of expansion of tundra vegetation due to global climatic deterioration 2 a late pliocene pleistocene maximum probably caused by glacial erosion and meltwater outwash significant amounts of marine organic carbon were deposited in baffin bay during middle miocene time suggesting higher surface water productivity triggered by the inflow of cold and nutrient rich arctic water masses the decrease in average surface water productivity to values similar to those of modern baffin bay occurred during the late miocene and were probably caused by development of a seasonal sea ice cover reaching maximum expansion during the past 3 4 m y

mining geology of the pond creek seam pikeville formation middle pennsylvanian in part of the eastern kentucky coal field usa abstract the pond creek seam is one of the leading producers of coal in the eastern kentucky coal field the geologic factors that affect mining were investigated in several underground mines and categorized in terms of coal thickness coal quality and roof control the limits of mining and thick coal are defined by splitting along the margin of the coal body within the coal body local thickness variation occurs because of 1 leader coal benches filling narrow elongated depressions 2 rider coal benches coming near to or merging with the main bench 3 overthrust coal benches being included along paleochannel margins 4 cutouts occurring beneath paleochannels and 5 very hard and unusual rock partings occurring along narrow elongated trends in the study area the coal is mostly mined as a compliance product sulfur contents are less than 1 and ash yields are less than 10 local increases in sulfur occur beneath sandstones and are inferred to represent post depositional migration of fluids through porous sands into the coal run of mine quality is also affected by several mine roof conditions and trends of densely concentrated rock partings which lead to increased in and out of seam dilution and overall ash content of the mined coal roof control is largely a function of a heterolithic facies mosaic of coastal estuarine origin regional fracture trends and unloading stress related to varying mine depth beneath the surface lateral variability of roof facies is the rule in most mines the largest falls occur beneath modern valleys and parallel fractures along paleochannel margins within tidally affected stackrock and beneath rider coals shale spalling kettlebottoms and falls within other more isolated facies also occur many of the lithofacies and falls related to bedding weaknesses within or between lithofacies occur along northeast southwest trends which can be projected in advance of mining fracture related falls occur independently of lithofacies trends along northwest southeast trends especially beneath modern valleys where overburden thickness decreases sharply differentiating roof falls related to these trends can aid in predicting roof quality in advance of mining

response of marine palynomorphs to neogene climate cooling in the iceland sea odp hole 907a abstract the present study on odp leg 151 hole 907a combines a detailed analysis of marine palynomorphs dinoflagellate cysts prasinophytes and acritarchs and a low resolution alkenone based sea surface temperature sst record for the interval between 14 5 and 2 5 ma and allows to investigate the relationship between palynomorph assemblages and the paleoenvironmental evolution of the iceland sea a high marine productivity is indicated in the middle miocene and palynomorphs and ssts both mirror the subsequent long term neogene climate deterioration the diverse middle miocene palynomorph assemblages clearly diminish towards the impoverished assemblages of the late pliocene parallel with a somewhat gradual decrease of ssts being as high as 20 c at 13 5 ma to around 8 c at 3 ma superimposed palynomorph assemblages not only reflect middle to late miocene climate variability partly coinciding with the short lived global miocene isotope events mi events but also the initiation of a proto thermohaline circulation across the middle miocene climate transition which led to increased meridionality in the nordic seas last occurrences of species cluster during three events in the late miocene to early pliocene and are ascribed to the progressive strengthening and freshening of the proto east greenland current towards modern conditions a significant high latitude cooling between 6 5 and 6 ma is depicted by the supraregional decahedrella event coeval with lowest miocene productivity and a sst decline in the early pliocene a transient warming is accompanied by surface water stratification and increased productivity that likely reflects a high latitude response to the global biogenic bloom the succeeding crash in palynomorph accumulation and a subsequent interval virtually barren of marine palynomorphs may be attributed to enhanced bottom water oxygenation and substantial sea ice cover and indicates that conditions seriously affecting marine productivity in the iceland sea were already established well before the marked expansion of the greenland ice sheet at 3 3 ma