coal depositional models for deltaic and alluvial plain sequences coal depositional models attempt to predict the distribution and geometry of coal beds within given sequences or provinces to date models proposed for coals of alluvial and deltaic origin have emphasized depositional environment as the controlling variable in this article i propose that subsidence regime and to a lesser extent sediment supply are the dominant controls upon coal distribution rather than environment of accumulation for this reason most existing coal depositional models are likely to have limited predictive capability

reference gravity stations on the igsn71 standard in britain and greece summary the international gravity standardisation net 1971 morelli et al 1974 includes no reference sites in greece we describe composite observations with lacoste and romberg lcr gravity meters which tie a newly established site at athens airport to igsn71 sites in rome and edinburgh as well as determining the absolute scale of the greek national calibration line on mount parnis as a by product the manufacturers scale of the lcr meter g 275 is found to require correction by the factor 1 000 622 f 0 000 027 against igsn71 using this factor we confirm the igsn71 scale in britain by deducing a gravity difference of 387 185 f 0 018 mgal between edinburgh a and teddington a compared with the igsn71 value of 387 19 f 0 030 mgal the same interval for the national gravity reference net 1973 masson smith et al 1974 is 397 128 f 0 023 mgal so that our observations confirm turnbull s 1986 conclusion that the ngrn73 connection to edinburgh turnhouse airport was faulty there are now no significant differences in either overall scale or individual station values between our observations on a selection of ngrn73 sites and those obtained under a program of re observation by the british geological survey however we found an error exceeding 0 2 mgal in one of the original ngrn73 values

decadal variability in the north pacific the eastern north pacific mode abstract decadal variability in the north pacific is studied in a series of coupled global ocean atmosphere simulations using coupled modeling surgery a set of modeling approaches that can be used to identify the origins and causes of a specific variability mode in the coupled climate system both modeling and observational studies suggest two distinctive internal modes in the north pacific the north pacific mode npm and the eastern north pacific mode enpm the enpm originates from atmospheric stochastic forcing through spatial resonance both local ocean atmosphere coupling and remote tropical teleconnective forcing can enhance the enpm but none of them is a necessary precondition the influence of the tropical forcing in the midlatitudes is dominated by atmospheric teleconnection while the oceanic teleconnection is negligible the upper ocean heat budget reveals that sst anomalies in the central north pacific and the eastern north pacific are generated by anomalous ekman advection and surface hea

basin modes in a tropical extratropical basin abstract the full spectrum of basin modes in a tropical extratropical basin is studied comprehensively in a linear shallow water system two sets of least damped basin modes are identified at the low frequency end is the planetary wave basin mode whose period is determined by the cross basin time of the planetary wave on the poleward boundary of the basin consistent with recent theories at the higher frequency end is the kelvin wave basin mode whose period is determined by the around basin traveling time of the kelvin wave sensitivity experiments are also performed on the eigenvalue problem to study the dynamics of these basin modes it is found that the period of the planetary wave basin mode is determined by an effective basin boundary that is always at a latitude no higher than the geometric basin boundary the effective poleward boundary is located at the most poleward latitude where the planetary wave can cross the entire basin it is also found that the kelvin wave basin modes are vulnerable t

how long is the memory of tropical ocean dynamics combining classic equatorial wave dynamics and midlatitude wave dynamics a unified view is proposed to account for the memory of tropical ocean dynamics in terms of oceanic basin modes it is shown that the dynamic memory of the ocean is bounded by the cross basin time of planetary waves along the poleward basin boundary for realistic ocean basins this memory originates from the mid and high latitude processes and is usually at interdecadal timescales

observations on the nature and origin of fusain abstract evidence for a wildfire origin of fusain is examined charcoal produced by natural fires and artificial charring resembles fossil fusain both in physical size and shape and in optical reflectance artificially charred leaves and naturally burnt wood are illustrated using the sem reflectance studies on modern charcoals suggest that much semifusinite may be produced by pyrolysis the ecological implications of a wildfire origin of fusain are discussed and it is concluded that fires have been a feature of terrestrial ecosystems from at least the late devonian

newly compiled gravity and topographic data banks of greece summary a brief description of the gravity and topographic data banks of greece is given about 22 000 gravity stations are included in the newly compiled gravity data bank from an initially available data set of 33 000 stations after the application of specific rejection criteria and classified in squares of 100 km x 100 km the data cover an area between 18 and 27 e and 33 and 42 n fig 1 a matrix of 2 km x 2 km mean elevation values was also estimated for the same area these data constitute the topographic data bank the preparation and structure of both data banks are also briefly discussed here key words gravity gravity anomalies greece topography introduction the immense increase during the last few decades in the amount of all kinds of collected data has led to the need for a more systematic treatment concerning their storage and handling compilation of data banks has proven to be a useful method in this respect the university of athens was provided with a catalogue

models of the geomorphology hydrology and development of domed peat bodies because peat accumulates only beneath the water table the shape of a peat body should reflect the shape of its water table and thus the hydrology of the peat body three different models successfully reproduce the observed peat dome morphology including a central bog plain in the first model the bog plain develops because peat accumulation is limited by anaerobic decay of peat beneath the water table with certain simplifying assumptions an analytic solution for this model can be obtained the other two models are more easily investigated numerically in the first model the initial peat accumulation rate is limited only by plant growth and decay and is the maximum rate observed during peat dome development as a peat dome expands laterally peat accumulation slows because the water table ceases to rise fast enough to preserve all the available plant material eventually anaerobic decay beneath the water table matches the rate of peat addition to the top of the peat body and net peat accumulation ceases 17 refs 2 tabs

sequence stratigraphy of paralic coal bearing strata an overview abstract sequence stratigraphy arose in the late 1980s to fundamentally change the science of stratigraphy former practice of labeling formations and erecting stratigraphic columns gave place to a dynamic genetic stratigraphic analysis where the main concern is about understanding the history of sedimentation and to establish models able to predict facies born and mainly applied to an environment of petroleum prospecting and exploration sequence stratigraphy has gained entrance to other branches of sedimentary geology the present paper gives a short introduction to sequence stratigraphic concepts and shows an overview of its application on coal bearing strata two case studies one from the early permian coals of the parana basin brazil and one from the lower cretaceous coals of the western canada sedimentary basin illustrate the concepts

stratigraphic and micropetrographic occurrences of pyrite in sediments at the confluence of carbonate and peat forming depositional systems southern florida u s a abstract this study was undertaken to investigate peat carbonate relationships in a modern coal forming setting with initial research on pyrite and sulfur contents relative to stratigraphic and petrographic conditions over 40 closely spaced cores were taken from transects from florida bay inland through mangrove swamps and freshwater everglades core stratigraphy confirms on overall transgressive sequence but new evidence supports a small regression within the overall transgression on average both total s and pyrite are lowest at inland sites highest near the coastline and intermediate in florida bay sediments total s is higher in marine than freshwater peats but freshwater peats overlain by marine peats are enriched in s in cores that start with peat at the top pyrite is generally absent or very low in the top 20 cm higher percentages of pyrite occur in carbonate rather than peat facies pyrite exists in three forms framboidal aggregates minute crystals and large solitary crystals most of the pyrite occurs as minute crystals m and framboidal aggregates the occurrence of large crystals 2 m is less common and generally restricted to the cavities of larger cells or cavities within other organics e g formminifera pollen grains fungal sclerotia a general relationship seem to exist in certain cases between the occurrence of spherical organic cell fillings and the occurrence of the framboidal form of pyrite

comparisons of central appalachian carboniferous coal beds by benches and a raised holocene peat deposit abstract three carboniferous age coals from southern west virginia u s a were examined at bench level and compared to a holocene peat deposit the snuggedy swamp south carolina u s a data for all deposits consisted of coal or peat thickness ash content and petrographic composition as well as parting or overlying clastic sediment thickness comparison of coal and parting thickness showed an inverse relationship in all cases bimodal distribution patterns for coal peat thickness versus area indicate that the transition between areas of extensive thick coal peat and extensive thin coal peat was rapid in the coal deposits at bench level both ash and organic inert content increased toward the transition to thin coal the areas of thick coal contained the highest vitrinite reactive contents and lowest ash values volumetrically this is similar to the distribution of low ash well preserved thick peat occurring in the central raised areas of the snuggedy swamp surrounded by areas of high ash decomposed peat subject to flooding although the depositional environments interpreted for each of the three coal beds and the snuggedy peat deposit differ widely the deposits themselves show similar distribution trends in thickness ash content and petrographic composition

precessional forced zonal triple pole anomalies in the tropical pacific annual cycle abstractbased on a transient simulation of the community earth system model we identified two anomalous zonal triple pole type annual cycles in the equatorial pacific sea surface temperature ss

sequence stratigraphic distribution of coaly rocks fundamental controls and paralic examples significant volumes of terrigenous organic matter can be preserved to form coals only when and where the overall increase in accommodation approximately equals the production rate of peat accommodation is a function of subsidence and base level for mires base level is very specifically the groundwater table in paralic settings the groundwater table is strongly controlled by sea level and the precipitation evaporation ratio peat accumulates over a range of rates but always with a definite maximum rate set by original organic productivity and space available below depositional base level groundwater table below a threshold accommodation rate nonzero no continuous peats accumulate due to falling or low groundwater table sedimentary bypass and extensive erosion by fluvial channels this is typical of upper highstand lowstand fan and basal lowstand wedge systems tracts higher accommodation rates provide relatively stable conditions with rising groundwater tables mires initiate and copyright 1997 the american association of petroleum geologists all rights reserved 1manuscript received september 7 1995 revised manuscript received november 25 1996 final acceptance may 5 1997 2exxon production research company 3120 buffalo speedway houston texas 77096 3exxon production research company 3120 buffalo speedway houston texas 77096 present address conoco inc p o box 2197 houston texas 77252 we benefited from the input and assistance of many people of special assistance were the teams involved in collaborative studies with esso australia and esso malaysia p moore m sloan j emmett b burns a partridge s creaney hanif hussein r hill r lovell and m feeley we also thank the rock springs team r beauboeuf p mclaughlin w devlin a carroll y y chen g grabowski jr k miskell gerhardt m farley r webster and j schwalbach group members d curry and j yeakel were always helpful we also enjoyed and profited from many discussions of these concepts with our colleagues outside exxon c diessel r boyd k shanley b zaitlin p mccabe m hendricks a cohen and m kirschbaum we thank the reviewers of company reports whose careful comments on several generations of this work improved it s creaney m feeley j van wagoner f wehr j yeakel and a young f weber and j zullig provided extensive management support k linke translated our sketches into the fine figures herein we value all the help

isometamorphic variations in the reflectance and fluorescence of vitrinite a key to depositional environment abstract petrographic investigations of serial ply samples from five high to medium volatile bituminous coal seams from australia 4 and canada 1 reveal substantial in seam variations in the reflectance and monochromatic microfluorescence intensities of the maceral subgroup telovitrinite the variations consist of one case of reflectance enhancement and fluorescence suppression and four cases of reflectance suppression and fluorescence enhancement the single case of reflectance enhancement and fluorescence suppression is due to the oxidation of the vitrinite nuclei at the sequence boundary between the bayswater and upper wynn seams in new south wales the four cases of reflectance suppression and fluorescence enhancement result from the syn and epigenetic absorption by the vitrinite nuclei of hydrogen donated by presumably anaerobic bacteria generated lipids two of the coals are marine influenced the liskeard seam from the bowen basin by combined syngenetic and epigenetic effects and the greta seam from the sydney basin mainly by epigenetic contact with sea water for both coals the results are strong vitrinite reflectance suppression and fluorescence enhancement the remaining two coals the bulli seam from the sydney basin and a coal seam from the gates formation in british columbia show moderate epigenetic effects on the optical properties of telovitrinite by fresh water in the bulli seam which was studied in two adjacent localities the reflectance suppression and fluorescence enhancement of telovitrinite are stronger under sandstone roof than under shale roof in some cases the epigenetic effects are superimposed on syngenetic telovitrinite reflectance and fluorescence variations resulting from the cogeneration and mixing of different telovitrinite precursors for example autochthonous roots and hypautochthonous or allochthonous shoots a measure of the degree of dispersal and mixing is the coefficient of variation of telovitrinite reflectance and or fluorescence this coefficient correlates well with detrital minerals and dispersed macerals e g inertodetrinite and to a lesser extent sporinite some comments are made on slitted so called pseudovitrinite which is regarded as a telovitrinite that was subjected to very weak post coalification desiccation and possibly oxidation without losing much of its thermoplastic properties

low frequency modes of tropical ocean dynamics abstract basinwide very low frequency vlf modes with zonal uniformly deepening and shoaling of the equatorial thermocline are found as solutions of linear shallow water equations with the meridional basin boundaries under an equatorial plane they can be understood as the free heat content recharge oscillations the interannual vlf modes had been recognized as the essential part of the coupled recharge oscillator theory for the el nino southern oscillation it is suggested that the decadal vlf modes may also be transformed into coupled modes relevant to the pacific decadal climate variability through the ocean atmosphere interaction in the tropics

relative sea level changes recorded by paralic liptinite enriched coal facies cycles middle jurassic muslingebjerg formation hochstetter forland northeast greenland abstract the middle jurassic muslingebjerg formation of hochstetter forland northeast greenland consists of a succession of shallow marine sandstones encasing four coal seams formed in low lying coastal mires the seams are up to 3 45 m thick and contain coal facies cycles with high liptinite contents up to 70 vol the cycles generally start with huminite rich bright or banded coal and end with dull coal or clayey coal coaly claystone the dull coals are characterized by a high proportion of liptinite commonly resinite and often mineral matter liptodetrinite resinite and cutinite dominate the liptinite maceral group similarity in the relative proportions of the liptinite macerals in the bright and dull coals and the general association of bright coal and dull coal with a high resinite concentration suggest that the dull coals represent a residue after selective removal of ligno cellulosic tissues in the precursor peat of primarily the bright lithotype the clayey coal coaly claystone lithotypes have high contents of mineral matter and commonly contain alginite and pyrite occurrence of pyrite in levels with high diasterane c 27 c 29 ratios and sometimes also alginite in the clayey coal coaly claystone lithotypes indicates a marine influence during flooding of the mires this suggests a causal link between base level rise in the coastal mires and relative sea level rise accommodation space available for thick peat accumulations was governed by overall relative sea level rise and the dulling upward cycles record outpacing of peat accumulation due to accelerated rise in base level relative sea level the muslingebjerg formation consists of four depositional sequences beginning with a thick coal seam resting on a sequence boundary peat accumulation reflects onset of base level rise in the coastal area and the coals represent the lower part of the transgressive systems tract the overlying shoreface sandstones form the upper part of the transgressive systems tract and a progradational highstand systems tract alternatively the two lower seams in the succession may form a transgressive regressive couplet separated by a lagoonal sandstone split in this case a sequence boundary occurs at the top of the upper regressive seam the dulling upward cycles within the coal seams represent parasequences or possibly higher order sequences minimum age estimates suggest that they accumulated over 4000 11000 yr

tropical ocean decadal variability and resonance of planetary wave basin modes part ii numerical study abstract oceanic response to stochastic wind forcing is studied in a tropical extratropical basin using two shallow water models a periodically forced model and a time forward model consistent with theory extratropical stochastic wind forces a decadal spectral peak in the tropical and eastern boundary ocean as a resonant response of the planetary wave basin mode this resonant response is characterized by a rather uniform amplitude and phase in the equatorial and eastern boundary region in comparison away from the eastern boundary the extratropical ocean is affected significantly by the local ekman pumping forcing with spectral peaks varying with location a complex eof ceof analysis of the time forward model simulation further suggests that these resonant responses are robust and can be extracted as the leading ceof modes thus the resonance of the planetary wave basin mode gives a physically based guideline for the interpretation of decadal oceanic variability in the tropical extratropical ocean

on balanced and unbalanced accommodation peat accumulation ratios in the cretaceous coals from gates formation western canada and their sequence stratigraphic significance coal composition was investigated by means of photometric and maceral analyses on closely spaced lithotype based strip samples over the full thickness of several paralic coal seams from the cretaceous gates formation of the western canadian sedimentary basin the aim of this investigation was to test various methods of identifying accommodation trends in coal and use them to refine sequence stratigraphic interpretation of continental sediments conventional sequence stratigraphy derives its subdivisions and significant surfaces from the records left by relative sea level oscillations these records either do not project into the continental realm or are difficult to recognise in clastic non marine sediments paralic coal seams have been selected to study this problem because they are not entirely removed from marine influence and compared with most inorganic deposits coal has stored a greater wealth of information that can be analysed at a higher level of resolution the study has led to the identification of five new surfaces with chronostratigraphic potential in the sequence stratigraphic analysis of non marine sediments two of these surfaces called paludification surface pas and terrestrialisation surface tes occur at the bases of the investigated coal seams while two other surfaces referred to as non marine flooding surface nfs and give up transgressive surface guts form the tops of the coal the fifth and probably most important new surface called the accommodation reversal surface ars is independent of any particular facies and may either coincide with some of the other surfaces or occur separately the proportion of detrital minerals has been used as the chief discriminator between different mire types and accommodation trends other useful indicators of mire type and peat dispersal have been the proportions of sporinite and inertodetrinite as well as some derived maceral and or mineral ratios e g the groundwater influence index and the tissue preservation index isometamorphic variations of telovitrinite reflectance and fluorescence as well as their coefficients of variation were also found to contribute to the identification of cyclic shifts between balanced and unbalanced accommodation peat accumulation ratios some of these cycles which are backed up by clastic stratigraphy appear to correspond to the development of shallowing upward and deepening upward parasequences superimposed high frequency low amplitude perturbations in the coal cycles relate to smaller scale accommodation cycles of sub parasequence level not always recognised in non marine strata these sub parasequence coal cycles do not always continue the shallowing upward trend typical of conventional parasequences several coals were found to contain stacks of small scale cycles with upward increasing accommodation signatures either in their lower or upper halves or over the whole seam section

coal seam splits and transgressive regressive coal couplets a key to stratigraphy of high frequency sequences a model of the stratigraphy of sequences in coal based on a subsurface case study of the coal bearing lower cretaceous mannville group of canada posits basinward progressive splitting patterns of thick regionally extensive paralic coal seams successive splits bounded by transgressive regressive coal seam couplets are interpreted to be fourth order sequences produced in single base level cycles stacked in a progradational pattern these fourth order sequences in turn form third order sequences thick regional seams form on top of a prograding platform by amalgamation of several fourth order sequences vertical profiles of coal properties geochemistry petrology and palynology in the lower and upper leaves of a split seam which constitute a transgressive regressive couplet would yield characteristic signatures revealing their transgressive and regressive nature respectively

tropical ocean decadal variability and resonance of planetary wave basin modes part i theory abstract oceanic response to decadal wind forcing is studied in a tropical extratropical basin using two classical theoretical shallow water wave models the equatorial wave model and the planetary wave model extratropical winds are found to generate significant thermocline variability in the tropical ocean with a spectral peak at decadal timescale the preferred decadal time of the response is due to the resonance of the gravest planetary wave basin modes the resonant response however is unimportant in the interior extratropical ocean where it is distorted by the forced response to local ekman pumping it is proposed that the resonance of planetary wave basin modes may provide a mechanism for the generation of decadal variability in the tropical ocean and potentially in the coupled ocean atmosphere system

rossby wave coastal kelvin wave interaction in the extratropics part i low frequency adjustment in a closed basin abstract the interaction of open and coastal oceans in a midlatitude ocean basin is investigated in light of rossby and coastal kelvin waves the basinwide pressure adjustment to an initial rossby wave packet is studied both analytically and numerically with the focus on the low frequency modulation of the resulting coastal kelvin wave it is shown that the incoming mass is redistributed by coastal kelvin waves as well as eastern boundary planetary waves while the incoming energy is lost mostly to short rossby waves at the western boundary the amplitude of the kelvin wave is determined by two mass redistribution processes a fast process due to the coastal kelvin wave along the ocean boundary and a slow process due to the eastern boundary planetary wave in the interior ocean the amplitude of the kelvin wave is smaller than that of the incident planetary wave because the initial mass of the rossby wave is spread to the entire basin in a midlatitude ocean basin the slow eastern boundary planetary wave

modeling evidence for enhanced el nino southern oscillation amplitude during the last glacial maximum we present a numerical eigenmode analysis of an intermediate el nin o southern oscillation enso model which is driven by present day observed background conditions as well as by simulated background conditions for the last glacial maximum lgm about 21 000 years ago the background conditions are obtained from two lgm simulations which were performed with the national center for atmospheric research climate system model csm1 4 and an earth system model of intermediate complexity ecbilt clio our analysis clearly shows that the leading present day unstable recharge discharge mode changes its stability as well as its frequency during lgm conditions simulated lgm background conditions were favorable to support large amplitude self sustained interannual enso variations in the tropical pacific our analysis indicates that off equatorial climate conditions as well as a shoaling of the thermocline play a crucial role in amplifying the lgm enso mode

1985 1999 gravity field variations across the asal rift insights on vertical movements and mass transfer repeated gravity measurements across the asal rift zone reveal that the central part of the northern rift might be subject to mass input in addition to vertical movements precise relative gravity measurements were made in 1985 1988 and 1999 temporal variations in the gravity field over the 11 and 14 yr periods reveal a probable relative gravity increase on the order of 30 gal 300 nm s2 in the central zone of the rift active zone since the ardoukoba rifting episode with respect to both sides of the rift the gravity data are compared with vertical deformation data collected by the french national geographical institute ign in 1984 and 2000 along 50 km of the across axis leveling profile the comparison shows that vertical movements alone cannot explain the observed gravity variations and that unlike in many other volcano studies our gravity and elevation changes cannot be modeled by a single process such as subsidence inflation or localized mass injection

global teleconnections of meridional overturning circulation anomalies there is a wide range of evidence from both models and palaeoclimatic data that indicates the possibility of abrupt changes in the oceanic meridional overturning circulation moc however much of our dynamical understanding of the moc comes from steady state models that rely upon the assumption of thermodynamic equilibrium and are therefore only valid on millennial time scales here a dynamical model for the global teleconnections of moc anomalies on annual to multidecadal time scales is developed it is based on a linear theory for the propagation of zonally integrated meridional transport anomalies in a reduced gravity ocean and allows for multiple ocean basins connected by a circumpolar channel to the south the theory demonstrates that the equator acts as a low pass filter to moc anomalies as a consequence moc anomalies on decadal and shorter time scales are confined to the hemispheric basin in which they are generated and have little impact on the remainder of the global ocean the linear theory is compared with the results of a global nonlinear numerical integration which it reproduces to a good approximation

the nature and influence of fire in carboniferous ecosystems fusain occurs widely in carboniferous coals and sediments it is now recognised to represent charcoal and be the product of wildfire the occurrence of fire is partly constrained by atmospheric oxygen levels availability and nature of fuel and by aspects of climate rainfall and seasonability in particular the majority of fires in the carboniferous were probably started by lightning strikes or by volcanic activity experiments on the charring of modern plants has shown that the reflectance of charcoal and hence fusain is directly related to temperature of formation different fire types may yield fusain assemblages of differing reflectance spectrums but it may be significant that many modern charcoal assemblages yield only semifusinites as seen by reflectance microscopy the significance of these findings is assessed in relation to the use of fusinites and semifusinites as depositional indicators as interpreted from coal petrology fires may have a dramatic effect on ecosystems not only causing changes in vegetational succession but also severe erosion can occur following a major fire which can be traced in depositional systems in this paper we document three major carboniferous sedimentary systems affected by fire clastic sedimentary systems using extensive fusain deposits in mid lower carboniferous near shore sediments in donegal ireland volcanic systems using late early carboniferous volcaniclastic sequences in the midland valley of scotland and coal and coal bearing sequences in the upper carboniferous westphalian b of the pennine basin england in the later settings the influence of fire in peat formation and succession is assessed in addition data on the vegetational composition of charcoal assemblages is considered it is concluded that fire plays a major role in many carboniferous ecosystems

multiple bench architecture and interpretations of original mire phases examples from the middle pennsylvanian of the central appalachian basin usa abstract coal seams often exhibit lateral and vertical variability in composition when sampled as a whole seam this variability is masked but if a seam is subdivided into correlateable components this variability can be tested and better understood herein an architectural approach is used to divide seams into intra seam components clastic splits and mineral partings as well as persistent fusain and durain layers can be used as intra seam bounding units to subdivide a seam into subdivisions called benches regional examination of lower and middle pennsylvanian age coal seams shows that many contain laterally persistent bounding surfaces that can be used to define multiple benches of coal within each seam inter bench analyses from some of the most extensively mined seams in the central appalachian basin show that individual benches often have different spatial and quality trends hence some component of whole seam variability is a function of changes in the relative contribution of these different benches to the seam as a whole many coal benches also exhibit intra bench variation in coal parameters intra bench variation can be analyzed in terms of parameters such as sulfur content and ash yield in order to address changes in coal quality for regional resource evaluation intra bench variation can also be analyzed in terms of a combination of palynologic petrographic and geochemical parameters termed compositional groups in order to better understand the development of the original mire systems compositional groups are defined by ranges of multiple criteria which are inferred to owe their origin to the mire type in which they formed vertical changes in compositional groups within coal benches can be used to infer paleo edaphic conditions during peat accumulation if seam thickness is a product of bench configuration and trends in compositional groups occur in benches then trends in quality can be marginally predicted based upon seam thickness and inferred bench architecture additionally changes in inter bench and intra bench thickness and compositional profiles can be used to infer original depositional controls such as paleotopography syndepositional structural movement and syndepositional clastic influx for more accurate reserve estimates

sequence stratigraphy and marine to nonmarine facies architecture of foreland basin strata book cliffs utah u s a the desert member of the blackhawk formation and the castlegate sandstone in the book cliffs of utah and colorado were analyzed to develop a model of sequence stratigraphy and facies architecture in foreland basins stratal architecture of these rocks is controlled by two regionally extensive surfaces of incision and subaerial exposure interpreted as major sequence boundaries and at least six surfaces of incision and subaerial exposure with more limited lateral extent interpreted as minor sequence boundaries each sequence boundary is a regionally correlatable single surface major sequence boundaries can be traced from marine into proximal alluvial plain environments sequence boundaries have different physical expressions depending upon where in the basin they are observed strata beneath sequence boundaries are unrelated to strata above and time lines cannot be carried across these boundaries flooding surfaces called parasequence or parasequence set boundaries also exert an important control on facies architecture based on parasequence stacking patterns position of sequence boundaries and facies associations the desert member and castlegate sandstone have been divided into sequences with durations of 200 000 to 300 000 yr there are an order of magnitude more sequences in this interval than are predicted by the global sea level chart of haq et al 1988 the major sequences have been divided into the following systems tracts or sequence sets 1 grassy highstand sequence set below the desert sequence boundary named for the grassy member of the blackhawk formation 2 desert lowstand transgressive and highstand systems tracts between the desert and castlegate sequence boundaries 3 castlegate lowstand sequence set resting on the castlegate sequence boundary and 4 castlegate transgressive systems tract parasequence stacking patterns suggest that the grassy highstand sequence set and the desert highstand systems tract were deposited during a relative rise in baselevel the grassy highstand sequence set is punctuated by minor relative falls in baselevel both of these stratal units contain thick

enso suppression due to weakening of the north atlantic thermohaline circulation changes of the north atlantic thermohaline circulation thc excite wave patterns that readjust the thermocline globally this paper examines the impact of a freshwater induced thc shutdown on the depth of the pacific thermocline and its subsequent modification of the el nino southern oscillation enso variability using an intermediate complexity global coupled atmosphere ocean sea ice model and an intermediate enso model respectively it is shown by performing a numerical eigenanalysis and transient simulations that a thc shutdown in the north atlantic goes along with reduced enso variability because of a deepening of the zonal mean tropical pacific thermocline a transient simulation also exhibits abrupt changes of enso behavior depending on the rate of thc change the global oceanic wave adjustment mechanism is shown to play a key role also on multidecadal time scales simulated multidecadal global sea surface temperature sst patterns show a large degree of similarity with previous climate reconstructions suggesting that the observed pan oceanic variability on these time scales is brought about by oceanic waves and by atmospheric teleconnections

a microgravimetric network in east central greece an area of potential seismic hazard summary the eastern mediterranean is a region of complex tectonic processes and associated horizontal and vertical displacements a high precision gravity network has been established in the atalanti area of central greece to monitor temporal gravity changes on an annual or more frequent basis a total of 68 sites have been measured in 1981 and 1982 with a maximum single instrument standard deviation of 0 08 gravity units after a least squares network adjustment analysis of the gravity differences between the two measuring epochs exhibits no change of gravity over the network with a precision of 0 1 1 gravity units it is proposed that the gravity values given form a stable base for continued observations which will enable the authors to resurvey the region in the event of precursory foreshocks observation of the atlantic network will continue on an annual basis preserving the same observation sequence for reasons of symmetry

vertical and lateral variation in the petrography of the upper cretaceous sunnyside coal of eastern utah usa implications for the recognition of high resolution accommodation changes in paralic coal seams the sunnyside member of the upper cretaceous blackhawk formation in the book cliffs of eastern utah is composed of coal bearing coastal plain strata and wave dominated shoreface deposits the member includes a thick up to 6 m laterally extensive coal seam which formed in a large ombrotrophic raised mire parallel to the shoreline of the western interior seaway the petrographic composition of the sunnyside coal was investigated by means of maceral analysis and telovitrinite reflectance determinations of closely spaced samples taken from seven vertical sections through the seam sampling was carried out in a combination of outcrop and underground mine sites using lithotype logging to determine sample spacing the excellent exposure in the study area enables accurate stratigraphic correlation between sampling localities which are spread over more than 30 km of depositional dip and 50 km of depositional strike the correlation of petrographic trends between the seven sampled sections demonstrates the reproducibility of the results and suggests that they represent regional scale accommodation changes as opposed to localised variation in the mire on this basis we are able to identify a high resolution record of accommodation change throughout the deposition of the sunnyside coal spanning two cycles of increasing and decreasing accommodation we are also able to identify a marine flooding surface within the coal which can be traced down depositional dip into the time equivalent shallow marine strata where it represents a parasequence boundary the proportion of detrital minerals is used as the main discriminator of accommodation trends within the coal other useful indicators of conditions in the mire include semifusinite pyrite and isometamorphic variations in telovitrinite reflectance

pacific decadal variability the tropical pacific mode and the north pacific mode pacific decadal variability is studied in a series of coupled global ocean atmosphere simulations aided by two modeling surgery strategies partial coupling pc and partial blocking pb the pc experiments retain full ocean atmosphere coupling in selected regions but constrain ocean atmosphere coupling elsewhere by prescribing the model climatological sst to force the atmospheric component of the coupled system in pb experiments sponge walls are inserted into the ocean component of the coupled model at specified latitudinal bands to block the extratropical tropical oceanic teleconnection both modeling and observational studies suggest that pacific decadal variability is composed of two distinct modes a decadal to bidecadal tropical pacific mode tpm and a multidecadal north pacific mode npm the pc and pb experiments showed that the tropical pacific mode originates predominantly from local coupled ocean atmosphere interaction within the tropical pacific extratropical tropical teleconnections although not a necessary precondition for the genesis of the tropical decadal variability can enhance sst variations in the tropics the decadal memory in the tropics seems to be associated with tropical higher baroclinic modes the north pacific mode originates from local atmospheric stochastic processes and coupled ocean atmosphere interaction atmospheric stochastic forcing can generate a weaker npm like pattern in both the atmosphere and ocean but with no preferred timescales in contrast coupled ocean atmosphere feedback can enhance the variability substantially and generate a basin scale multidecadal mode in the north pacific the multidecadal memory in the midlatitudes seems to be associated with the delayed response of the subtropical subpolar gyre to wind stress variation in the central north pacific and the slow growing decaying of sst anomalies that propagate eastward in the kuroshio extension region oceanic dynamics particularly the advection of the mean temperature by anomalous meridional surface ekman flow and western boundary currents plays an important role in generating the north pacific mode

organic facies development within middle jurassic coal seams danish central graben and evidence for relative sea level control on peat accumulation in a coastal plain environment abstract during middle jurassic times peat accumulated in coastal plain environments in an overall transgressive setting in the sogne basin danish central graben in the north sea the coal seams occur in nonmarine to marginal marine deposits coal petrographic analyses of the seams in the west lulu 2 well supplemented with a sequence stratigraphic analysis suggest that peat accumulation was controlled by relative sea level changes in west lulu 2 the coal bearing upper part of the middle jurassic is divided into sequences a and b the sediments of sequence a are part of a transgressive systems tract whereas the overlying sequence b contains lowstand and transgressive systems tract deposits the coals are situated in the transgressive systems tracts the coal seams formed during a rapid relative sea level rise are generally characterized by petrographic features related to a permanently high groundwater table coals formed during a slow rise typically are drier in their petrographic composition the highest pyrite contents are observed in the wet coals the coal seams represent terrestrial equivalents to marine flooding surfaces or to transgressive surfaces if they are situated at the base of a transgressive systems tract a thick coal seam zone is associated with the stratigraphic level of the maximum flooding surface which correlates with the time of formation of the highest accommodation space