stress magnitude and orientation in the potiguar basin brazil implications on faulting style and reactivation 1 we analyzed borehole breakout data and drilling induced tensile fractures derived from resistivity image logs run at 10 oil wells to derive the orientation of the maximum horizontal stress shmax from the potiguar basin in the continental margin of brazil stress magnitudes are derived from density logs for the vertical stress mini frac tests for the minimum horizontal stress shmin and rock strength laboratory analysis to estimate the shmax magnitudes we compared these results with the stress regime and shmax orientation derived from nine earthquake series located in the crystalline basement where seismicity is concentrated and previous breakout data from the basin in the basin the shmax gradient is 20 0 mpa km and the shmax shmin ratio is 1 154 indicating a normal tectonic stress regime from 0 5 to 2 0 km whereas the shmax gradient of 24 5 mpa km and shmax shmin ratio of 1 396 indicate a transition from a normal to strike slip stress regime at 2 5 to 4 0 km the deeper stress regime in the basin is similar to that in the basement at 1 12 km depth this transition of the tectonic stress regime is consistent with an incipient tectonic inversion in the basin we note that the shmax orientation rotates from nw se in the western part of the potiguar basin to e w in its central and eastern parts roughly following the shoreline geometry indicating that local features such as flexural stresses influence the local scale 100 km stress pattern we also conclude that the basement is critically stressed but not the basin

concentration and character of pahs and other hydrocarbons in coals of varying rank implications for environmental studies of soils and sediments containing particulate coal abstract particulate coal can occur in soils and sediments from both natural and anthropogenic sources its presence can influence the concentrations of regulated and more bioavailable pollutants through its geosorbent qualities and its own contribution of total extractable hydrocarbons teh including polycyclic aromatic hydrocarbons pahs and biomarkers extractable pahs in coal also can potentially affect pah based source and maturity ratios of soil or sediment extracts which can be used to assess the source s of pahs this study reports on the absolute concentrations of teh the 16 priority pollutant pahs 27 alkylated pahs and sulfur containing aromatics and selected biomarkers in 15 coals ranging in rank from lignite to anthracite unlike most previous studies in the fuel science or geochemical literature the coals herein were extracted using dichloromethane at room temperature an epa method 3500 type method common in environmental laboratories thereby allowing comparison of these results to environmental studies the concentrations of teh ranged from 8 2 to 2500 g g coal dry wt with a maximum yield among high volatile bituminous coals the teh fingerprints were variable and some of these resembled those of other forms of contamination the concentrations of priority pollutant pahs ranged from 35 to 11 000 ng g coal dry wt or 38 to 12 000 ng g carbon and varied with coal rank reaching a maximum within the high volatile bituminous rank the distributions of extractable pahs and numerous pah ratios conventionally used as source and or maturity parameters also varied with coal rank emphasizing that particulate coal in soils and sediments cannot be universally represented by a single set of diagnostic parameters hopanoid and sterane biomarker yields also varied with rank reaching a maximum in high volatile bituminous coals and were low relative to pahs because particulate coal often co occurs with other sources of hydrocarbons in soils and sediments the data presented herein may prove useful in allocating coal versus non coal sources on a mass balance basis

petrological and geochemical composition of lignite from the d field kolubara basin serbia abstract the upper miocene lignite from the main coal seam in the d field kolubara basin is a typical humic coal with huminite liptinite and inertinite concentrations of up to 83 7 vol 17 2 vol and 15 5 vol respectively in the huminite group textinite and ulminite are the most abundant macerals with variable amounts of densinite and attrinite liptodetrinite and sporinite are the most common macerals of the liptinite group while inertodetrinite is the most abundant maceral of the inertinite group the mineral matter consists mostly of clay minerals the main sources of organic matter were gymnosperms conifers and microbial biomass followed by angiosperms based on composition of saturated and aromatic diterpenoids it has been established that coal forming plants belonged to the gymnosperm families taxodiaceae podocarpaceae cupressaceae araucariaceae phyllocladaceae and pinaceae peatification occurred in neutral to slightly acidic fresh water environment composition and distribution of biomarkers show that diagenetic changes of the organic matter were mainly governed by bacterial activity in a suboxic to oxic environment based on distribution of aromatic diterpenoids a novel diagenetic pathway for transformation of abietane type precursors under suboxic to oxic conditions is proposed variations in compositions of macerals and biomarkers are in concordance with pronounced seasonality during pontian which caused changes in the water level redox conditions during peatification and to some extent vegetation differences in the paleo plant communities

poleward stationary eddy heat transport by the tibetan plateau and equatorward shift of westerlies during northern winter the orographic effect of the tibetan plateau on atmospheric poleward heat transport is investigated using an atmospheric general circulation model the linear interference between the tibetan plateau induced winds and the eddy temperature field associated with the land sea thermal contrast is a key factor for enhancing the poleward stationary eddy heat transport specifically tibetan plateau induced stationary waves producenortherliesoverthecoldeasterneurasiancontinent leadingtoapolewardheattransport inanother hot spot of stationary eddy heat transport over the eastern north pacific tibetan plateau induced stationary waves transport relatively warm marine air northward in an experiment where the tibetan plateau is removed the poleward heat transport is mostly accomplished by transient eddies similar to the southern hemisphere in the presence of the tibetan plateau the enhanced stationary eddy heat transport is offset by a comparable reduction in transient eddy heat transport this compensation between stationary and transient eddy heat transport is seen in observed interannual variability both the model and observations indicate that an enhanced poleward heat transport by stationary waves weakens transienteddiesbydecreasingthemeridionaltemperaturegradientandtheassociatedwesterliesinmidlatitudes

brazilian structural provinces an introduction abstract the territory of brazil coincides almost entirely with the south american platform the crystalline core of the continent its basement is composed of ancient metamorphic and igneous rocks and it has not suffered any tectonic regeneration since the beginning of the phanerozoic sedimentary rocks with almost horizontal bedding cover this crystalline basement this latter shows ages as old as early precambrian although ages between 500 and 1000 m y are conspicuously frequent the cratonic areas became consolidated more than 1700 m y ago whereas the fold belts formed essentially between 500 and 1700 m y ago the sedimentary cover accumulated from the early silurian in three large intracratonic basins until the platform became completely stabilized a late jurassic to early cretaceous reactivation caused by the break up of the ancient gondwana continent created another basin sequence chiefly along the atlantic continental margin based on the nature of the crystalline basement rocks and the sedimentary cover ten structural provinces can be distinguished 1 rio branco province in the north of the country occupied by the guyana shield and still only poorly known with an important fold belt developed during the so called transamazonian cycle 2000 200m y with high grade metamorphic rocks and only slight influence of later events 2 tapajos province in central brazil corresponding to the amazonas or guaporecraton showing chiefly precambrian crystalline rocks and behaving as an cratonic area during the phanerozoic 3 sa o francisco province located on the atlantic shield with its basement covered by rocks of different ages chiefly affected by the brasiliano cycle between 1000 and 500 m y and constituting another cratonic area 4 tocantins province between the amazonas and sa o francisco cratons with the oldest rocks in its centre ages over 2600 m y and at the eastern and western borders metamorphic sequences of various fold belts and almost no phanerozoic deposits 5 mantiqueira province located along the southern part of the atlantic coast affected chiefly by the brasiliano folding cycle 6 borborema province in the northeast brazilian fold belt affected by the brasiliano cycle in a very complex way and with important faulted zones it was reactivated in phanerozoic times when also sedimentary covers accumulated 7 amazonas province represented by the amazonas sedimentary basin syneclise and subdivided into four parts by three important arcs 8 parnaiba province coinciding with the piauf maranha o syneclise and filled with a rather thick sedimentary sequence 9 paranaprovince the sedimentary basin of southern brazil in which the well known late paleozoic glaciation features are found and which possesses an extensive cover of basaltic rocks of late jurassic to early cretaceous age 10 coastal province and continental margin the youngest structural unit developed during the separation of the continent and represented by rift valleys and coastal basins filled with mesozoic cenozoic deposits of various kinds

hadley circulation response to orbital precession part ii subtropical continent the responseof the monsoonaland annual meanhadley circulation to orbital precession is examined in an idealized atmospheric general circulation model with a simplified representation of land surface processes in subtropical latitudes when perihelion occurs in the summer of a hemisphere with a subtropical continent changesin the top of atmosphereenergy balance togetherwith a polewardshift ofthe monsoonalcirculation boundary lead to a strengthening of the monsoonal circulation spatial variations in surface heat capacity determine whether radiative perturbations are balanced by energy storage or by atmospheric energy fluxes althoughorbitalprecessiondoesnotaffectannual meaninsolation theannual meanhadleycirculationdoes respond to orbital precession because its sensitivity to radiative changes varies over the course of the year the monsoonal circulation in summer is near the angular momentum conserving limit and responds directly to radiative changes whereas in winter the circulation is affected by the momentum fluxes of extratropical eddies and is less sensitive to radiative changes

stationary eddy response to surface boundary forcing idealized gcm experiments abstract a set of atmospheric general circulation model agcm experiments under idealized conditions is performed to investigate atmospheric response to surface boundary forcing by extratropical land sea contrast large scale orography and tropical sea surface temperature sst distribution stationary eddies forced by the extratropical land sea distribution are strongest in high latitudes but their amplitudes are modest and comparable to internal chaotic variability by contrast the stationary eddy response to zonal variations in tropical sst is strong and robust in both the subtropics and midlatitudes while these sst forced stationary waves are trapped within the troposphere those induced by orography show a strong vertical propagation into the stratosphere analysis of transient eddies indicates that orography is effective in generating a zonally localized storm track while extratropical land sea contrast has little effect on the zonal variation of upper level storm activity a vorticity budget a

source apportionment of the hydrocarbon background in sediment cores from hecate strait a pristine sea on the west coast of british columbia canada abstract significant reserves of oil and gas have been predicted for hecate strait a pristine semi enclosed sea on the continental shelf adjacent to british columbia on the west coast of canada to establish a baseline for the natural background of hydrocarbons in sediment prior to any further offshore oil and gas development or increase in oil tanker traffic in the hecate strait region three sediment box cores were collected along a west to east transect across southern hecate strait in september 2003 210 pb measurements established that the bottom sections date to 1920 pre 1800 and 1870 respectively which predate any significant industrial development on the coast alkane and polycyclic aromatic hydrocarbon pah concentrations are low in most sediment samples and both the concentrations and fluxes differ little between surface and bottom core sections pah profiles exhibit a dominance of alkyl pahs for each alkyl pah homologous series with varying amounts of parent unsubstituted pahs while alkane chromatograms show no unresolved complex mixture ucm and there is little change in composition between present day and pre 1800 sediments for most parameters principal components analysis pca models and pah and biomarker ratios indicate that composition patterns are consistent with low and varying natural petrogenic and pyrogenic inputs with little or no anthropogenic input the most likely primary source of petrogenic pahs to the sediments is cenozoic lignites from the skonun formation which outcrops on haida gwai and underlies most of hecate strait two subsurface sections deposited in 1990 and 1930 in the core from milbanke sound on the east side of the transect have elevated concentrations for the alkyl phenanthrene anthracenes and dibenzothiophenes with no ucm and most likely also have a source in immature coal this study suggests that the hecate strait environment has low hydrocarbon concentrations with an apparent minor role for oil seeps and a likelihood that most of the petrogenic pah sources are shales or immature coals with limited pah bioavailability if these characteristics are representative of hecate strait sediments overlying the queen charlotte basin it may mean that biota are likely unadapted to the presence of oil and thus would be more sensitive to exposure to oil from an oil spill than those in a more impacted environment

earthquake sequences in the southern block of the pernambuco lineament ne brazil stress field and seismotectonic implications abstract the pernambuco lineament pel is an e w striking 700 km long shear belt located in the central part of the borborema province brazil seismic sequences have been monitored in the region since 1991 and they are clearly correlated with the main shear belt and its ne trending branches a new sequence of small earthquakes occurred in april 2010 away from the main belt in the southern block of the lineament we monitored this seismicity using a ten station network for 154 days and used the observations to determine the nature of the seismicity and the stress patterns in addition we used data from five previous local seismograph networks to determine the stress tensor the results indicate that the seismicity is concentrated in three clusters two of which are associated with normal faults the first strikes 96 dips 51 and has a rake of 65 and the second strikes 253 dips 64 and has a rake of 120 these faults are 2 2 km and 1 5 km long and 2 0 3 0 km and 3 0 3 5 km deep respectively and are not correlated with the pernambuco lineament or its ne trending branches the inversion of focal mechanisms from our investigation and previous studies indicates e w trending compression and n s trending extension that affects both the northern and southern blocks of the pel the new data indicate that the fault behavior in the shear zone area is more complex than has previously been observed along reactivated mylonitic belts

the middle eocene markushegy subbituminous coal hungary paleoenvironmental implications from petrographical and geochemical studies abstract samples from two coal seams of the markushegy underground mine hungary were investigated for variations in maceral composition petrography based facies indicators and various geochemical parameters using three seam profiles both seams originate from a topogenous mire and evolved within a peneplaned coastal area covered with eutrophic swamps the presence of foraminifera and marine algae in the marly layers is indicative of marine ingressions coal facies characterisation from these parameters is combined with the results from biomarker analyses of soluble organic matter in order to reconstruct the depositional environment and to relate petrography based indicators to the molecular composition the contents of macerals of the liptinite group are positively correlated with soluble organic matter som yields and hydrogen index hi consistent with maceral composition and high hi values enhanced proportions of n alkanes of intermediate molecular weight n c21 25 which are predominantly found in macrophytes are obtained from samples of the marly shales the final drowning of the mire is reflected by decreasing pristane phytane ratios due to the rise of the ground water table and the establishment of anaerobic conditions the observed positive correlation between pristane phytane ratios and inertinite percentages suggests that at least in the markushegy deposit both parameters reflect variations in redox conditions of the mire the predominance of angiosperms in the peat forming vegetation of the markushegy coal is evidenced by the high relative proportions of angiosperm derived triterpenoids the influence of the relative proportion of fossil wood on tissue preservation tpi is indicated by the positive relationship of the concentration of land plant derived terpenoid hydrocarbons and tpi the degree of gelification of plant tissue gi is governed by the microbial activity in the mire as indicated by a negative relationship between gi and the steroids hopanoids concentration ratios the variation of the 13c values of coal is obviously governed by the relative contribution of plant lipids to the biomass the obtained negative relationship between 13c of the coal and gi is explained by the effect of cellulose decomposition and microbial activity on the isotopic composition of the organic matter

storm track dynamics this paper reviews the current state of observational theoretical and modeling knowledge of the midlatitude storm tracks of the northern hemisphere cool season observed storm track structures and variations form the first part of the review the climatological storm track structure is described and the seasonal interannual and interdecadal storm track variations are discussed in particular the observation that the pacific storm track exhibits a marked minimum during midwinter when the background baroclinicity is strongest and a new finding that storm tracks exhibit notable variations in their intensity on decadal timescales are highlighted as challenges that any comprehensive storm track theory or model has to be able to address physical processes important to storm track dynamics make up the second part of the review the roles played by baroclinic processes linear instability downstream development barotropic modulation and diabatic heating are discussed understanding of these processes forms the core of our current theoretical knowledge of storm track dynamics and provides a context within which both observational and modeling results can be interpreted the eddy energy budget is presented to show that all of these processes are important in the maintenance of the storm tracks the final part of the review deals with the ability to model storm tracks the success as well as remaining problems in idealized storm track modeling which is based on a linearized dynamical system are discussed perhaps on a more pragmatic side it is pointed out that while the current generation of atmospheric general circulation models faithfully reproduce the climatological storm track structure and to a certain extent the seasonal and enso related interannual variations of storm tracks in depth comparisons between observed and modeled storm track variations are still lacking

hypocentral relocation using clustering along planes constraints implications for fault geometry summary hypocentre location is an ill posed inverse problem even assuming that the velocity model is known because different sets of hypocentre locations may satisfy the fitting criterion we present a regularized hypocentre inversion in which the constraints of spatial proximity of the hypocentres to target planes are used this constraint introduces the geological bias that earthquakes might occur along fault planes here the target planes may be either 1 planes specified by the interpreter or 2 planes fitting groups of events we assume also that initial estimates of hypocentres and origin times are available then the initial hypocentre estimates origin times and target planes are used as input to an inversion problem to relocate the hypocentres so that the maximum possible clustering of events along the given planes is attained matching the observed traveltimes we use l1 norm for data fitting l2 norm for the plane proximity criterion and a polytope algorithm to minimize the functional results from synthetic and real data indicate that the plane proximity constraint allows for hypocentre relocation presenting a high degree of clustering along planes the real data example is an intraplate earthquake sequence in ne brazil our methodology defined the geometry and strike of fault segments close to known geology and focal mechanism data in addition the new method indicates that the fault is characterized by a splay geometry in its southern end and that more than three fault segments are necessary to explain the hypocentre distribution

petrographical and organic geochemical study of the kovin lignite deposit serbia abstract the origin of the organic matter om and the characteristics of the depositional environment of lignites from the upper miocene kovin deposit hosting three coal seams of serbia were evaluated based on petrographic data bulk organic geochemical parameters biomarker analysis and stable isotope geochemistry 13c of individual biomarkers samples were collected from four boreholes gd 601 and gd 603 the a field and kb 79 and kb 91 the b field representing different parts of coal seams i ii and iii investigated lignites are typical humic coals the om of lignites is derived from woody vegetation and herbaceous peat forming plants with prevalence of the former in most samples peat forming vegetation is characterized by abundant decay resistant gymnosperm coniferous plants followed by a low amount of angiosperms lignite forming plants mostly belonged to the gymnosperm families cupressaceae taxodiaceae phyllocladaceae and pinaceae slight input of ferns fungi and aquatic macrophyta to lignite om is also evident distributions of hopanoids and isotopic compositions of these biomarkers reflect the activity of various microbial populations represented by methanotrophic chemoautotrophic and heterotrophic bacteria during diagenesis prominent c28 28 30 bisnorneohop 13 18 ene was observed for the first time in the lignite extracts according to the 13c value it was probably derived from chemoautotrophic bacteria c28 28 30 bisnorneohop 13 18 ene could be one of the possible precursors of a series of orphan aromatic hopanoids bearing an ethyl group at c 21 via progressive aromatization peatification proceeded in a fresh water environment under variable redox conditions from anoxic to slightly oxic all three coal seams are heterogeneous the lower parts of the coal seams represent a topogenous fresh water peat mire with open water areas which was subjected to inundations the upper parts of coal seams represent a wet forest swamp with relatively stable conditions despite the observed variations in all three coal seams the mean values of petrographic and organic geochemical parameters suggest general increasing of wetness and establishment of more stable conditions from seam iii to seam i maceral and biomarker data indicate that rapid flooding of the bogs stopped peat growth in all three coal seams relatively frequent variations in all three coal seams followed by repetition of lignite characteristics depict well the pronounced seasonality e g short term cycles of the climate during late miocene in investigated area

further investigation of the impact of idealized continents and sst distributions on the northern hemisphere storm tracks abstractbuilding on previous studies of the basic ingredients of the north atlantic storm track examining land sea contrast orography and sst this article investigates the impact of eurasian topography and pacific sst anomalies on north pacific and atlantic storm tracks through a hierarchy of atmospheric gcm simulations using idealized boundary conditions in the hadley centre hadgam1 atmospheric circulation model the himalaya tibet mountain complex is found to play a crucial role in shaping the north pacific storm track the northward deflection of the westerly flow around northern tibet generates an extensive pool of very cold air in the northeastern tip of the asian continent which strengthens the meridional temperature gradient and favors baroclinic growth in the western pacific the kuroshio sst front is also instrumental in strengthening the pacific storm track through its impact on near surface baroclinicity while the warm waters around indonesia tend to weaken it through the impact on barocl

upper crustal earthquake swarms in sao caetano reactivation of the pernambuco shear zone and trending branches in intraplate brazil abstract seismogenic fault reactivation of continental scale structures has been observed in a few intraplate areas but its cause is still a matter of debate the objective of the present study is to analyze two seismic swarms that occurred along the ew trending pernambuco ductile shear zone and in a ne trending branch in 2007 and 2010 in sao caetano county northeastern brazil we studied both epicentral areas using a nine and a seven station network during 180 and 54 days respectively the results indicate that the 2007 swarm correspond to a right lateral strike slip fault with a normal component of slip strike 74 dip 60 and rake 145 and the 2010 swarm corresponds to a normal fault strike 265 dip 79 and rake 91 the former reactivated a ne trending branch whereas the latter reactivated the main e w trending mylonitic belt of the pernambuco shear zone these results are consistent with seismogenic reactivation of this major structure generated by the present day ew trending compression and ns trending extension as observed by previous studies this shear zone was reactivated as rift faults in the cretaceous during the south america africa breakup however our study confirms that the basement fabric such as continental scale ductile shear zones show evidence of crustal weakness outside areas of previous rifting and it reveals the potential for large earthquakes along dormant rift segments associated with major basement shear belts

observation based estimates of global and basin ocean meridional heat transport time series abstractocean meridional heat transports mhts are deduced as a residual using energy budgets to produce latitude versus time series for the globe indo pacific and atlantic the top of atmospher

mineralogy petrography and organic geochemistry of miocene coal seams in the kinik coalfield soma basin western turkey insights into depositional environment and palaeovegetation abstract the kinik coalfield is located in the south westernmost part of the soma basin in western turkey and hosts all three miocene coal seams from bottom to top km2 km3 and kp1 this study presents the coal petrographical mineralogical and organic geochemical features of samples collected from two deep cores samples from seam km2 generally display low ash yields and high toc content whereas the km3 and kp1 seams are characterized by relatively high ash yields and low toc values furthermore total s content of the kp1 is very high up to 7 0 on dry basis the maceral composition the coal facies diagrams and the distributions of n alkanes and diterpenoids indicate changes of depositional conditions and vegetation in the palaeomires of the km2 seam during early miocene the precursor peat of km2 seam started accumulating under limnotelmatic conditions followed by pure telmatic ones consequently initial mixed vegetation was replaced by a conifer dominant assemblage in the palaeomires in the upper parts of the km2 seam the coal facies indices and high concentrations of n alkanes along with the relatively low di di tri terpenoid ratios are indicators of the higher contribution of herbaceous species and minor abundance of conifers in the palaeomires of km3 and kp1 seams nevertheless the mineralogical composition of the km3 and kp1 seams indicate increased clastic input and alkalinity in the palaeomires that could reduce preservation of organic matter thus high ash yields and low toc were obtained from these seams in addition sulphate rich water supply along with synchronous pyroclastic air borne input into the palaeomires caused elevated total s content of the kp1 seam

the effects of orography on midlatitude northern hemisphere dry climates abstract the role of mountains in maintaining extensive midlatitude arid regions in the northern hemisphere was investigated using simulations from the gfdl global climate model with and without orography in the integration with mountains dry climates were simulated over central asia and the interior of north america in good agreement with the observed climate in contrast moist climates were simulated in the same regions in the integration without mountains during all season but summer large amplitude stationary waves occur in response to the tibetan plateau and rocky mountains the midlatitude dry regions are located upstream of the troughs of these waves where general subsidence and relatively infrequent storm development occur and precipitation is thus inhibited in summer this mechanism contributes to the dryness of interior north america as a stationary wave trough remains east of the rockies but is not effective in eurasia due to seasonal changes in the atmospheric circulation the dryness

investigating the local atmospheric response to a realistic shift in the oyashio sea surface temperature front abstractthe local atmospheric response to a realistic shift of the oyashio extension sst front in the western north pacific is analyzed using a high resolution hr 0 25 version of the global community atmosphere model version 5 cam5 a northward shift in the sst front causes an atmospheric response consisting of a weak surface wind anomaly but a strong vertical circulation extending throughout the troposphere in the lower troposphere most of the sst anomaly induced diabatic heating is balanced by poleward transient eddy heat and moisture fluxes collectively this response differs from the circulation suggested by linear dynamics where extratropical sst forcing produces shallow anomalous heating balanced by strong equatorward cold air advection driven by an anomalous stationary surface low to the east this latter response however is obtained by repeating the same experiment except using a relatively low resolution lr 1 version of cam5 comparison to observations suggests that the hr respo

the basic ingredients of the north atlantic storm track part ii sea surface temperatures abstractthe impact of north atlantic sst patterns on the storm track is investigated using a hierarchy of gcm simulations using idealized aquaplanet and semirealistic boundary conditions in the atmospheric component hadam3 of the third climate configuration of the met office unified model hadcm3 this framework enables the mechanisms determining the tropospheric response to north atlantic sst patterns to be examined both in isolation and in combination with continental scale landmasses and orography in isolation a gulf stream sst pattern acts to strengthen the downstream storm track while a north atlantic drift sst pattern weakens it these changes are consistent with changes in the extratropical sst gradient and near surface baroclinicity and each storm track response is associated with a consistent change in the tropospheric jet structure locally enhanced near surface horizontal wind convergence is found over the warm side of strengthened sst gradients associated with ascending air and i

the petrology organic geochemistry and palynology of tertiary age eureka sound group coals arctic canada abstract tertiary age lignites from arctic canada were analysed by petrographical palynological and organic geochemical methods results from petrographic analyses indicate the predominance of wood derived macerals humotelinite group in seams from the strathcona and stenkul fiord areas whereas in the bache peninsula area many seams are characterized by the predominance of detrital macerals humodetrinite and have also higher inertinite contents palynological assemblages are dominated by taxodiaceae pollen whereas pinaceae pollen and pteridophyte spores are less common angiosperm derived pollen contents are quite variable organic geochemical results indicate that norisopimarane and pimarane are the most abundant diterpenoids cadalene was present in the aromatic fractions of all samples with other components such as simonellite and retene in variable abundance rock eval data obtained from stenkul fiord area samples indicate low petroleum generation potential for this predominantly woody material the depositional environment at strathcona and stenkul fiords was that of a forested swamp which formed in a lagoonal alluvial plain setting palynomorph assemblages petrographic indices and the abundance of diterpenoids suggest that the mire flora was dominated by gymnosperms although locally angiosperms may also have been abundant as indicated by the occurrence of tetra and pentacyclic aromatic hydrocarbons at bache peninsula the mire was less forested as indicated by palynological assemblages typical for a marsh environment and petrographic characteristics such as low tissue preservation and the abundance of detrial macerals

organic geochemical characterization of a miocene core sample from haughton impact structure devon island nunavut canadian high arctic extremely well preserved sedimentary deposits in the haughton impact structure his provide a unique record of the post impact miocene lacustrine depositional environment detailed organic geochemical characterization of a hydrocarbon impregnated band found in a core from the crater lake sedimentary infill reveals a complex source history for the hydrocarbons these include contributions from eroded pre and post impact formations together with inputs from contemporaneous flora and fauna a deep possibly lower paleozoic petroleum as well as a contribution from hydrothermally altered organic biopolymers geochemical data coupled with paleolimnology and geology proves to be a valuable tool for studying the provenance of hydrocarbons associated with the his and can give insights not only into the post impact geology but also into processes that may contribute to the generation of petroleum fluids at other impact sites

organic geochemistry of the lower miocene oberdorf lignite styrian basin austria its relation to petrography palynology and the palaeoenvironment abstract in the oberdorf trough at the northwestern margin of the styrian basin austria an up to 36 m thick lower miocene ottnangian lignite seam occurs within the fluvial koflach voitsberg formation previous results indicate that the lignite originated in a topogenous mire within a wet forest swamp palaeoenvironment differences in soluble organic matter som yield of borehole samples from the lignite seam are related to free lipids present in plant waxes or resins and the presence of thermally labile polymers indicated by the contents of liptinite macerals i e resinite suberinite and liptodetrinite the n alkane distribution patterns are dominated by high molecular weight lipids with marked odd over even predominance originating from plant waxes a contribution of algae to the even numbered short chain lipids observed in considerable amounts in the footwall sediments is proposed terpenoid biomarkers characteristic for conifers and angiosperms were detected consistent with palynomorphic spectra which are dominated by forest swamp pollen taxodiaceae cupressaceae and pollen from plants living in a mixed mesophytic forest excellent relationships between higher plant biomarker composition and palynologic data indicate that the organic geochemical results reflect the varying inputs of coniferales vs angiosperms the data further imply that cuparene may be used for taxonomical differentiation of coniferales families organic geochemical data provide evidence that the content of land plant derived biomarkers is controlled by the input of resin rich conifers concentrations of hopanoids dominated by hop 17 21 ene generally increase towards the top of the lignite a section characterised by high extents of aromatisation of triterpenoid biomarkers the results suggest that the aromatisation of angiosperm derived biomarkers may be governed by the activity of anaerobic rather than by aerobic bacteria however changes in the depositional environment and palynologic facies during peat formation probably influenced the origin and fate of angiosperm derived triterpenoids the results indicate how biomarker composition may contribute to the evaluation of environmental changes cross correlations of organic geochemical parameters with palynological data and petrography based facies indicators will provide further insights in the peat forming vegetation and biogeochemical activities in the mire

biomarker and micropetrographic investigations of coal from the krepoljin brown coal basin serbia abstract we investigated early diagenetic processes of the extractable organic matter from the miocene freshwater sequence which consists of coal fragments in clays sandstones and shales alternating with continuous brown coal layers we examined eight coals thirteen sediments and three non coaly underground layers the molecular assemblages of the identified aliphatic hydrocarbons in the krepoljin basin reflect the abundance of plant taxa as precursors or participants in the early diagenetic stage the data provide insight into the conditions prevailing in the lakes and bogs during early diagenesis the dominance of diterpanes indicates that the prevalent of the organic matter was of gymnosperous origin the hopanoid contents are considered to reflect microbial activity that the organic matter in the miocene krepoljin coal basin is immature was confirmed by the presence of biolipids such as hopanes c 27 17 h trisnorhopan saturated and aromatized abietanes pimaranes and phyllocladanes the most abundant compounds in all samples indicate a predominantly higher plant input related to the coniferous group but identification of the individual plant families was not possible amyrin and other triterpenoid derived triaromatic and triaromatic c ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms unsaturated compounds 2 triterpanes early intermediaries in the diagenetic transformation of angiosperms also indicate a low degree of sediment maturity

tropospheric precursors of anomalous northern hemisphere stratospheric polar vortices regional extratropical tropospheric variability in the north pacific and eastern europe is well correlated with variability in the northern hemisphere wintertime stratospheric polar vortex in both the ecmwf reanalysis record and in the whole atmosphere community climate model to explain this correlation the link between stratospheric vertical eliassen palm flux variability and tropospheric variability is analyzed simple reasoning shows that variability in the north pacific and eastern europe can deepen or flatten the wintertime tropospheric stationary waves and in particular its wavenumber 1 and 2 components thus providing a physical explanation for the correlation between these regions and vortex weakening these two pathways begin to weaken the upper stratospheric vortex nearly immediately with a peak influence apparent after a lag of some 20 days the influence then appears to propagate downward in time as expected from wave mean flow interaction theory these patterns are influenced by enso and october eurasian snow cover perturbations in the vortex induced by the two regions add linearly these two patterns and the quasi biennial oscillation qbo are linearly related to 40 of polar vortex variability during winter in the reanalysis record

mountain uplift and surface temperature changes mountain uplift significantly affects both sea surface temperature sst and land surface temperature this was studied using a coupled atmosphere mixed layer ocean model with and without mountains the global mean sst dropped 1 4 c with mountain uplift mainly due to increased lower tropospheric clouds in the subtropical eastern pacific increased clouds hinder solar radiation into the ocean and lower sst the increased frequency of stratus incidence is related to subtropical anticyclones intensified by a strong temperature contrast between the continent and ocean in mountainous regions land surface temperature drops due to the lapse rate effect when this effect is eliminated the continental interior does not become as cool with mountain uplift because clouds become fewer and the surface drier due to decreased moisture transport southern asia becomes cooler because monsoon induced precipitation wets the ground and increases clouds our result showed greater northern high latitude temperature changes than the previous study indicating the importance of cloud related feedback in paleoclimate modeling

the role of stationary eddies in shaping midlatitude storm tracks transient and stationary eddies shape the extratropical climate through their transport of heat moisture and momentum in the zonal mean the transports by transient eddies dominate over those by stationary eddies but this is not necessarily the case locally in particular in storm track entrance and exit regions during winter stationary eddies and their interactions with the mean flow dominate the atmospheric energy transport here it is shown that stationary eddies can shape storm tracks and control where they terminate by modifying local baroclinicity simulations with an idealized aquaplanet gcm show that zonally localized surface heating alone e g ocean heat flux convergence gives rise to storm tracks which have a well defined length scale that is similar to that of earth s storm tracks the storm tracks terminate downstream of the surface heating even in the absence of continents at a distance controlled by the stationary rossby wavelength scale stationary eddies play a dual role within about half a rossby wavelength downstream of the heating region stationary eddy energy fluxes increase the baroclinicity and therefore contribute to energizing the storm track farther downstream enhanced poleward and upward energy transport by stationary eddies reduces the baroclinicity by reducing the meridional temperature gradients and enhancing the static stability transports both of sensible and latent heat water vapor play important roles in determining where storm tracks terminate

alkane and pah biomarkers as tracers of terrigenous organic carbon in arctic ocean sediments abstract we present the first sedimentary biomarker study encompassing the entire arctic ocean a large data set of organic markers for terrigenous petroleum and combustion inputs alkanes hopanes and steranes parent and alkyl polycyclic aromatic hydrocarbons pahs is examined for patterns in space and time using principal components analysis pca and partial least squares pls biomarker patterns reveal the central arctic ocean basin sediments to be compositionally distinct from those of the mackenzie river beaufort sea and barents sea but similar to those of the laptev sea pah distributions reflected in pah ratios and pca projections demonstrate that arctic ocean sediment is dominated by natural inputs to the extent that anthropogenic combustion pahs are not significant we find only modest changes between the glacial and post glacial sediments for atmospherically transported hydrocarbon biomarkers while particle associated biomarkers were captured strongly at basin edges during the glacial period and much more evenly transported across basins during the post glacial period the orders of magnitude decreases in particle associated petrogenic alkanes and pahs in central basins during glacial times coupled with the uniformity of most petrogenic biomarker parameters for most basin and shelf locations reflect a massive reduction in ice transport that makes the margins the most likely source of petrogenic material for the pleistocene holocene central arctic basins the proximity of large coal deposits of various maturity levels along the lena river the overlap in pah and biomarker composition of the laptev sea and surficial sediments from the central arctic ocean and the location of the laptev sea at the origin of the main transpolar drift all point to eroded coals from the lena river laptev sea as the likely source of petrogenic hydrocarbons to the central arctic ocean the ubiquitous presence of allochthonous coal in arctic ocean surface sediments provides a major constraint on the use of petrogenic biomarkers to infer the presence of subsurface petroleum reserves

alkane and polycyclic aromatic hydrocarbons in sediments and benthic invertebrates of the northern chukchi sea abstract the hanna shoal region represents an important northern gateway for transport and deposition in the chukchi sea this study determined the concentration and distribution of organic contaminants aliphatic hydrocarbon and polycyclic aromatic hydrocarbons pahs in surface sediments from 34 sites across hanna shoal up to 31 total pahs including parent and alkyl homologues were detected with total concentrations ranging from a low of 168 ng g 1 the western flank of hanna shoal station h34 to 1147 ng g 1 at station in barrow canyon station barc5 alkyl pahs were more abundant than parent structures and accounted for 53 64 of the summed concentrations suggesting overall at background levels

is the gulf stream responsible for europe s mild winters is the transport of heat northward by the gulf stream and north atlantic drift and its subsequent release into the midlatitude westerlies the reason why europe s winters are so much milder than those of eastern north america and other places at the same latitude here it is shown that the principal cause of this temperature difference is advection by the mean winds south westerlies bring warm maritime air into europe and north westerlies bring frigid continental air into north eastern north america further analysis of the ocean surface heat budget shows that the majority of the heat released during winter from the ocean to the atmosphere is accounted for by the seasonal release of heat previously absorbed and not by ocean heat flux convergence therefore the existence of the winter temperature contrast between western europe and eastern north america does not require a dynamical ocean two experiments with an atmospheric general circulation model coupled to an ocean mixed layer confirm this conclusion the difference in winter temperatures across the north atlantic and the difference between western europe and western north america is essentially the same in these models whether or not the movement of heat by the ocean is accounted for in an additional experiment with no mountains the flow across the ocean is more zonal western europe is cooled the trough east of the rockies is weakened and the cold of north eastern north america is ameliorated in all experiments the west coast of europe is warmer than the west coast of north america at the same latitude whether or not ocean heat transport is accounted for in summary the deviations from zonal symmetry of winter temperatures in the northern hemisphere are fundamentally caused by the atmospheric circulation interacting with the oceanic mixed layer copyright 2002 royal meteorological society

local shear wave observations in joao câmara northeast brazil 1 we present shear wave splitting data from a 10 km aperture eight station digital three component seismograph network which operated from december 1992 to august 1994 near joao c mara 5 33 s 35 51 w to record shear waves from continuing microearthquake activity persisting 6 years after a main shock in november 1986 previous aftershock recording had shown remarkably impulsive simple seismograms and hypocentral errors of typically 200 m in a structure of near uniform wave speed but only one station was three component the pattern of polarization directions shown is consistent with the trend of precambrian foliation observed in the field it is therefore concluded that these shear wave observations are controlled by the seismic anisotropy associated with the precambrian foliation and hence bear the signature of the paleo stress field i e the precambrian deformation regime this conclusion has important implications for the interpretation of shear wave splitting observations made in crustal crystalline rock because other authors have asserted that shear wave splitting normally results from the effect of stress aligned fluid filled cracks extensive dilatancy anisotropy or eda eda is by contrast a signature of the present day stress field in this region there is firm evidence that the present day maximum compressive stress is e w this evidence comes from earthquake focal mechanisms and borehole breakout data and is summarized in the world stress map we therefore conclude that our present data are in maximum conflict with an interpretation in terms of eda our interpretation is supported by the observation that delay times are consistent with those expected from modeling of elastic waves in the crust

the basic ingredients of the north atlantic storm track part i land sea contrast and orography understanding and predicting changes in storm tracks over longer time scales is a challenging problem particularly in the north atlantic this is due in part to the complex range of forcings land sea contrast orography sea surface temperatures etc that combine to produce the structure of the storm track the impact of land sea contrast and midlatitude orography on the north atlantic storm track is investigated through a hierarchy of gcm simulations using idealized and semirealistic boundary conditions in a highresolution version of the hadley centre atmosphere model hadam3 this framework captures the largescale essence of features such as the north and south american continents eurasia and the rocky mountains enabling the results to be applied more directly to realistic modeling situations than was possible with previous idealized studies the physical processes by which the forcing mechanisms impact the large scale flow and the midlatitude storm tracks are discussed the characteristics of the north american continent are found to be very important in generating the structure of the north atlantic storm track in particular the southwest northeast tilt in the upper tropospheric jet produced by southward deflection of the westerly flow incident on the rocky mountains leads to enhanced storm development along an axis close to that of the continent s eastern coastline the approximately triangular shape of north america also enables a cold pool of air to develop in the northeast intensifying the surface temperature contrast across the eastern coastline consistent with further enhancements of baroclinicity and storm growth along the same axis

the role of precambrian mylonitic belts and present day stress field in the coseismic reactivation of the pernambuco lineament brazil abstract the pernambuco lineament is a steeply dipping continental scale ductile shear zone rooted within the precambrian lithosphere of intraplate northeastern brazil it was formed during the brasiliano orogeny 600 ma and reactivated during the pangea breakup in the cretaceous when it controlled fault propagation and sediment accumulation in several rift basins the region is now under an e w trending horizontal compression and n s trending extension and faulting occurs predominantly in a strike slip regime we investigated two aftershock sequences and the preexisting tectonic fabrics along the pernambuco lineament in order to evaluate the role of these fabrics in the coseismic reactivation of continental scale structures the lineaments consist of a main ene wsw trending mylonitic belt about 2 3 km wide and two secondary ne trending mylonitic belts about 100 m wide they both present steeply dipping mylonitic foliations and shallowing plunging stretching lineations the mylonites present granitoid protoliths and mineral parageneses that range from amphibolite to greenschist facies brittle deformation overprints the ductile fabric in all mylonitic belts in 1991 coseismic reactivation nucleated along the ene wsw striking 3 3 5 6 km deep normal fault of less than 1 km in length in the main mylonitic belt in 2002 seismicity migrated to a ne trending secondary mylonitic branch and moved as a right lateral strike slip 1 2 km long 3 8 4 9 km deep fault plane both fault segments reactivated the mylonitic foliation and form part of a major system we conclude that the interplay between the present day stress field and preexisting fabrics controls seismogenic fault location attitude and kinematics the pernambuco lineament is an example of a long lived continental scale structure where selective reactivation has occurred other shear zones in the region also show a long history of brittle reactivation and present similar orientation in relation to the present day stress axes they might be dormant structures prone for reactivation under the present day stress field

aliphatic and aromatic terpenoid biomarkers in cretaceous and paleogene angiosperm fossils from japan abstract the distributions of aliphatic and aromatic terpenoids in cretaceous and paleogene angiosperm fossils from japan were investigated aliphatic a ring degraded oleanane ursane and lupane were found in all samples in addition aliphatic gymnosperm derived diterpenoids were detected in significant quantities aromatic oleanane type triterpenoids were the major components with ursane and lupane type triterpenoids being minor compounds in all angiosperm fossils in a cretaceous gymnosperm fossil major components included aliphatic labdane isopimarane and abietane type diterpenoids aromatic abietane type diterpenoids and chrysene and picene type polyaromatic hydrocarbons pahs trace amounts of oleanane ursane and lupane type triterpenoids were also identified it is likely that the aromatic triterpenoids were introduced to the gymnosperm fossil from the angiosperm derived material in the sediments we defined an angiosperm gymnosperm index al agi as an alternative to the aliphatic triterpenoid diterpenoid ratio proposed in the literature the al agi index may underestimate the angiosperm contribution because the aliphatic angiosperm derived triterpenoids are more readily converted to aromatic counterparts than the diterpenoids during diagenesis an aromatic angiosperm gymnosperm index ar agi can be calculated using aromatic diterpenoids and triterpenoids we suggest that ar agi is best calculated using only the oleanane ursane and lupane type aromatic triterpenoids and that the chrysene and picene type pahs be excluded

relationships between coal quality and organic geochemical parameters a case study of the hafik coal deposits sivas basin turkey abstract this study provides coal quality organic petrographic and organic geochemical data on tertiary subbituminous coal of the hafik area northwestern part of the sivas basin turkey coal petrological studies along with proximate and ultimate analyses were undertaken to determine the organic petrographic characteristics of the hafik coals huminite reflectances were found to be between 0 38 and 0 48 corresponding to an organic material rich and coal layers values characteristic of low maturity this parameter shows a good correlation with calorific values average 21 060 kj kg and average t max 422 c mineral matter diagenesis indicating immaturity the studied coals and organic material underwent only low grade transformation a consequence of low lithostatic pressure therefore the hafik coals are actually subbituminous in rank rock eval analysis results show types ii iii and iii kerogens the organic fraction of the coals is mostly comprised of humic group macerals gelinites with small percentages derived from the inertinite and liptinite groups in this study organic petrographic organic geochemical and coal quality data were compared the hafik deposit is a high ash high sulfur coal the mineral matter of the coals is comprised mainly of calcite and clay minerals

understanding the seasonality of orographically forced stationary waves interaction between mechanical and thermal forcing abstract idealized simulations of the atmosphere s stationary response to the rockies tibetan plateau and the greenland ice sheet are made using a nonlinear quasigeostrophic model and are compared to observations observational data indicate low level heating cooling occurs above the rockies and tibet in the summer winter low level cooling is found above greenland in both seasons the atmosphere responds to both diabatic heating termed thermal forcing and low level flow being obstructed by the mountain s presence termed mechanical forcing the response to thermal and mechanical forcing together can be very different from the response to either forcing individually the presence of modest low level heating or cooling 1 5 k day 1 causes significant changes to the mechanical forcing and thereby to the stationary wave response for example while the nonlinear response to mechanical forcing and low level heating is characterized by a cyclone over the orography the response to mechanical forc

the building blocks of northern hemisphere wintertime stationary waves abstractan intermediate complexity moist general circulation model is used to investigate the forcing of stationary waves in the northern hemisphere boreal winter by land sea contrast horizontal h

the petroleum potential of some tertiary lignites from northern greece as determined using pyrolysis and organic petrological techniques abstract oil condensate and gas have recently been discovered in the thermaikos gulf area of northern greece the source of these hydrocarbons is not known although there is a possibility that more mature equivalents of certain tertiary brown coals and lignites may be responsible a contribution from tertiary terrestrial organic matter to the epanomi oil is supported by its biomarker distributions especially the predominance of triterpenoid compounds other than hopanes in the m z 191 mass fragmentogram in this study the hydrocarbon potential of a suite of greek tertiary lignites is first examined using rock eval analysis three samples are then further investigated using organic petrography and gas chromatography gc and gas chromatography mass spectrometry gc ms of the extracted hydrocarbon fractions as well as by hydrous pyrolysis an intermontane lignite 6og 5 contains fluorescing huminite together with resinite on extraction this resinite is found to be of predominantly diterpenoid origin rock eval and hydrous pyrolysis support previous proposals that diterpenoid resinite needs a lower activation energy to generate hydrocarbons than most other types of organic matter a sample of a lignite deposited in a deltaic environment mm 3 contains a more diverse collection of liptinite macerals with resinite again predominating the resinite appears to be mostly of triterpenoid and sesterterpenoid origin the best hydrocarbon potential is shown by a sample deposited in a lagoonal environment kas 3 little discrete resinite is observed in this sample but it does contain abundant fluorescing huminite although it has a low s 1 s 1 s 2 ratio it gives a high yield on solvent extraction during which a significant fraction of the s2 is removed the fluorescence of the huminite after extraction is greatly reduced the hydrocarbons of the extract are believed to be predominantly derived from triterpenoid resinite unlike the pyrolysates of the other two lignites but in common with the epanomi oil the triterpenoids in the kas 3 pyrolysate are dominated by resin derived compounds rather than hopanes this and other similarities between the composition of the pyrolysates of kas 3 and the oil support the possibility that a more mature equivalent of this lignite could be the source of the epanomi oil

petrological organic geochemical and geochemical characteristics of coal from the soko mine serbia abstract a petrological organic geochemical and geochemical study was performed on coal samples from the soko mine soko banja basin serbia ten coal and two carbonaceous clay samples were collected from fresh working faces in the underground brown coal mine from different parts of the main coal seam the lower miocene low rank coal of the soko mine is a typical humic coal with huminite concentrations of up to 76 2 vol liptinite less than 14 vol and inertinite less than 11 vol ulminite is the most abundant maceral with variable amounts of densinite and clay minerals sporinite and resinite are the most common macerals of the liptinite group inertodetrinite is the most abundant maceral of the inertinite group the mineral bituminous groundmass identified in some coal samples and carbonaceous marly clay indicate sub aquatic origin and strong bacterial decomposition the mean random huminite reflectance ulminite b for the main coal seam is 0 40 0 05 rr which is typical for an immature to early mature stage of organic matter the extract yields from the coal of the soko banja basin ranges from 9413 to 14 096 ppm in which alkanes constituted 1 0 20 1 aromatics 1 3 14 7 asphaltenes 28 1 76 2 and resins 20 2 43 5 the saturated hydrocarbon fractions included n c15 to n c32 with an odd carbon number that predominate in almost all the samples the contents of n c27 and n c29 alkanes are extremely high in some samples as a contribution of epicuticular waxes from higher plants acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction and the pristane phytane pr ph ratio varies between 0 56 and 3 13 which implies anaerobic to oxic conditions during sedimentation the most abundant diterpanes were abietane dehydroabietane and 16 h phyllocladane in samples from the upper part of the coal seam diterpanes are the dominant constituents of the alkane fraction polycyclic alkanes of the triterpane type are important constituents of alkane fractions the occurrence of and type hopanes from c27 to c31 but without c28 is typical for the soko banja coals the major and trace elements in the coal were analysed using x ray fluorescence xrf and inductively coupled plasma mass spectrometry icp ms in comparison with world lignites using the geometric mean value the coal from the soko banja basin has a high content of strontium 306 953 mg kg higher values than the world lignites were obtained for mo 3 614 mg kg ni 8 119 mg kg se 0 884 mg kg u 2 642 mg kg and w 0 148 mg kg correlation analysis shows inorganic affinity for almost all the major and trace elements except for s which has an organic affinity

the geology petrography and palynology of tertiary coals from the eureka sound group at strathcona fiord and bache peninsula ellesmere island arctic canada abstract coal seams of substantial thicknesses and lateral continuity are developed in the expedition and iceberg bay formations at strathcona fiord and in the expedition formation at bache peninsula the coals are lignite subbituminous in rank and have low to moderate sulphur and variable ash contents at strathcona fiord resources have been estimated to be in the order of 1 billion tonnes whereas at bache peninsula estimated resources are 100 million tonnes the coals at strathcona fiord are characterized by the dominance of wood derived macerals of the humotelinite group whereas at bache peninsula the coals have high amounts of detrital macerals humodetrinite and also have significant amounts of inertinite macerals pollen and spore assemblages in coals from the iceberg bay formation at strathcona fiord are dominated by taxodiaceace pollen with less and variable amounts of pinaceae pollen pteridophyte spores and angiosperm pollen the pollen and spore assemblages indicate a late paleocene early eocene age of the iceberg bay formation coals the expedition formation coals at bache peninsula have in general a somewhat less diverse pollen and spore assemblage and show a larger input of fern and sphagnum spores the pollen and spore assemblages in expedition formation coals at bache peninsula are indicative of early paleocene age the depositional environment for iceberg bay formation coals at strathcona fiord is that of a forested swamp which formed on a broad coastal plain at bache peninsula peats formed in broad valleys in which a fluviatile lacustrine environment of deposition prevailed the mires were likely less forested than at strathcona fiord as indicated by the abundance of ferns and sphagnum spores and the very low content of wood derived macerals of the humotelinite group the pollen assemblages in both expidition and iceberg bay formation coals indicate a temperate climate and moderate precipitation during peat accumulation

northern winter stationary waves theory and modeling a review is provided of stationary wave theory the theory for the deviations from zonal symmetry of the climate to help focus the discussion the authors concentrate exclusively on northern winter several theoretical issues including the external rossby wave dispersion relation and vertical structure critical latitude absorption the nonlinear response to orography and the interaction of forced wave trains with preexisting zonal asymmetries are chosen for discussion while simultaneously presenting a decomposition of the wintertime stationary wave field using a nonlinear steady state model

molecular composition of a leaf and root bearing oligocene oxbow lake clay in the weisselster basin germany abstract a plant fossil bearing clay profile from the upper oligocene thierbach strata weisselster basin germany has been sectioned into horizons and the plant macrofossils of each section surface have been identified by morphological and anatomical studies in the upper half of the profile leaves from populus germanica and carpinus grandis and branchlets from the conifer taxodium balticum vel t dubium dominate the horizons while the lower part contains only root remains of unknown higher plants in the soxhlet extracted samples from each section n alkanes n alkanols n carboxylic acids and several terpenoids amyrin 24 25 dinoreleana 1 3 5 10 12 tetraene olean 12 en 3 one simonellite and hop 17 21 ene were identified by combined gas chromatography mass spectrometry the comparison of the extracted chemical compounds and the macrofossil record of the profile shows that simonellite occurs preferentially in the taxodium bearing horizons n alkanes n alkanols n carboxylic acids and amyrin were found in all sections but are enriched in the root containing part of the profile the distribution of hop 17 21 ene is independent of the input of higher plant remains

some seismological and geometric features of intraplate earthquakes to understand the nature and cause of intraplate earthquakes we carried out a systematic search for common features associated with them various geological geophysical and seismic data were analyzed and geometric and seismic parameters were compared for 29 intraplate events m 4 5 occurring worldwide the results suggest that intraplate earthquakes occur by the reactivation of pre existing zones of weakness in a compressional stress regime which is generally oriented parallel to the absolute direction of plate motion two styles of faulting were observed for type a earthquakes observed in the eastern united states eastern china western europe and west africa deformation occurs by strike slip motion on steeply dipping faults type b events are usually associated with thrust or normal faulting and were observed in eastern canada fennoscandia australia and peninsular india focal depths did not explain the differences between type a and type b earthquakes rather the differences are due to the perturbation of a regional stress field by a local stress field the regional stress field for type a events is primarily due to ridge push forces the method of stress perturbation varied from region to region the earthquakes in the type b category were further divided into three subcategories type b1 occurring in eastern canada and fennoscandia type b2 occurring in australia peninsular india and central brazil and type b3 occurring in the gulf coast of the u s the inferred causes of the perturbing stresses are deglaciation intracontinental resistive forces resulting from the collision of plates and the deposition of a large thickness of sediments respectively type a events were found to be associated with intersecting faults and generally supported the intersection model of talwani 1988 and had analogs in plate boundary events

on the three dimensional propagation of stationary waves abstract a locally applicable nonzonally averaged conservation relation is derived for quasi geostrophic stationary waves on a zonal flow a generalization of the eliassen palm relation the flux which appears in this relation constitutes it is argued a useful diagnostic of the three dimensional propagation of stationary wave activity this is illustrated by application to a simple theoretical model of a forced rossby wave train and to a northern hemisphere winter climatology results of the latter procedure suggest that the major forcing of the stationary wave field derives from the orographic effects of the tibetan plateau and from nonorographic effects diabatic heating and or interaction with transient eddies in the western north atlantic and north pacific oceans and siberia no evidence is found in the data for wave trains of tropical origin forcing by the orographic effects of the rocky mountains seems to be of secondary importance

was the arctic eocene rainforest monsoonal estimates of seasonal precipitation from early eocene megafloras from ellesmere island nunavut abstract the early eocene was the warmest interval of the cenozoic and included within it were several hyperthermal events with the paleocene eocene thermal maximum petm the most pronounced of these these globally warm climates extended into the arctic and substantive paleobotanical evidence for high arctic precipitation map 150 cm yr is indicative of an arctic rainforest which contradicts some climate models that show low arctic precipitation prior studies of arctic early eocene wood stable isotope chemistry however have shown a summer peak in precipitation which suggests modern analogs are best sought on the summer wet east coast of the asia e g china japan south korea not the winter wet west coasts of the pacific northwest of north america furthermore some prior modeling data suggest that highly seasonal monsoon type summer wet precipitation regimes i e summer map 55 characterized certain mid and lower latitude regions in the early to mid eocene presented here is a new analysis using leaf physiognomy of 3 leaf megafloras split lake stenkul fiord and strathcona fiord and palynofloral bioclimatic analysis from the margaret formation from ellesmere island placed stratigraphically as early eocene possibly occurring during or following one of the early eocene hyperthermals these new data indicate high summer precipitation in the arctic during the early eocene which in part corroborates the results from eocene wood chemistry nevertheless in contradiction to the wood analysis monsoonal conditions are not indicated by our analysis consistent with current modeling studies high summer light season and winter dark season precipitation in the eocene arctic during hyperthermals would have contributed to regional warmth

investigation on the lignite deposits of surkha mine saurashtra basin gujarat western india their depositional history and hydrocarbon generation potential abstract an integrated approach is adopted to study the lignite deposits of surkha mine associated with the khadsaliya clays formation eocene of saurashtra basin western india the compilation of detailed investigation includes organic petrographical palynofacies and geochemical analyses the type and amount of organic matter and its relation to palaeoenvironmental conditions have been determined and discussed along with its significance as hydrocarbon source the macerals of huminite group show dominance av 61 over the liptinite and inertinite groups the petrographical indices gi tpi gwi vi indicate wood dominated precursors of peat were deposited in limno telmatic to telmatic regime under mesotrophic hydrological conditions in palynofacies analysis it is observed that the particulate organic matter is dominated by the phytoclasts group av 69 followed by the amorphous organic matter aom and palynomorphs the biomarker signatures show angiosperm and gymnosperm source vegetation the presence of sesquiterpenoids indicate the occurrence of dipterocarpaceae flora suggesting the existence of rain forest vegetation in the vicinity of depositional site the kaurane type of diterpenoids suggest the presence of conifers among the source flora the extrapolation of organic matter data on tyson s app diagram along with the pr n c 17 vs ph n c 18 plot indicate that the deposition took place in dysoxic suboxic conditions with intermittent shifting of the environment in proximal settings the huminite reflectance values av 0 31 r r show a good correlation with gross calorific values av 3917 cal g and average t max value 416 c of the lignites furthermore the abundance of thermally unstable hop 17 21 ene and hopane indicate immature stage of lignites these lignites contain high toc av 35 wt and low ash yields the volatile matter carbon and oxygen contents are relatively high whereas sulphur content is moderate and hydrogen and nitrogen contents are comparatively low in all the lignite samples the hydrogen index values vary between 53 and 538 mg hc g toc the atomic values of h c range from 0 47 to 1 04 and of o c from 0 20 to 0 29 overall the lignite bearing sequence is characterized by type ii iii admixed kerogens organic matters and has potential to generate hydrocarbons upon maturation

linear simulation of the stationary eddies in a gcm part ii the mountain model abstract the validity of linear stationary wave theory in accounting for the zonal asymmetries of the winter averaged tropospheric circulation obtained in a general circulation model gcm is ascertained the steady linear primitive equation model used towards this end has the same vertical and zonal resolution as the spectral gcm but is finite differenced in the meridional direction it is linearized about a zonally symmetric basic state and forced by topography and 3 dimensional diabatic heating and transient flux convergence fields all of which are taken from the gcm as in part i in which we studied a gcm with a flat lower boundary we obtained the best correspondence between the gcm and the linear solutions when strong rayleigh friction is included in the linear model not only near the surface but in the interior of the tropical troposphere as well there is sufficient quantitative correspondence between the gcm and the linear solution to justify decomposing the linear simulation into parts for

representation of topography in spectral climate models and its effect on simulated precipitation abstract spectral climate models are distinguished by their representation of variables as finite sums of spherical harmonics with coefficients computed by an orthogonal projection of the variables onto the spherical harmonics representing the surface elevation in this manner results in its contamination by gibbs like truncation artifacts which appear as spurious valleys and mountain chains in the topography these gibbs ripples are present in the surface topographies of spectral climate models from a number of research institutions integrations of the geophysical fluid dynamics laboratory gfdl climate model over a range of horizontal resolutions indicate that the gibbs ripples lead to spurious small scale extrema in the spatial distribution of precipitation this cellular precipitation pathology becomes more pronounced with increasing horizontal resolution causing a deterioration in the fidelity of simulated precipitation in higher resolution models a method is described for reducing the gib

glacial to postglacial transformation of organic input pathways in arctic ocean basins 1 the arctic ocean is undergoing rapid loss in ice cover with yet unknown consequences for the cycling of organic material here we examine persistent terrigenous land based alkane and polycyclic aromatic hydrocarbons with vascular plant combustion and petrogenic sources in seven cores collected from all major basins of the arctic ocean for insight as to how organic cycling at the last glacial maximum compares to the present day we find only modest changes between the glacial and postglacial sediments for atmospherically transported hydrocarbon biomarkers demonstrating that glacial sea ice was not a barrier to atmospheric inputs in stark contrast particle associated biomarkers were captured strongly at basin edges during the glacial period and much more evenly transported across basins during the postglacial period evidently the capture of organic matter shifted from the slopes to the shelves as the latter flooded during the holocene and the transpolar drift and beaufort gyre evolved from minor carriers of plant detritus from the glacial ocean margins to major modern transporters of shelf sediment to the basins this suggests that changes in organic transport currently accompanying the loss of sea ice are likely to be very different from those that occurred at the end of the last glacial period

paleoenvironmental implications from biomarker and stable isotope investigations on the pliocene velenje lignite seam slovenia a pliocene lignite seam up to 160 m thick occurs in the velenje basin slovenia the seam originated in a topogenous mire and evolved within a non marine transgressive setting differences in soluble organic matter yield and hydrocarbon content of borehole samples from the lignite are related to differences in the composition of free lipids of microbial origin and or hydrocarbons derived from the biogeochemical degradation of plant tissue variations of the redox conditions within the mire are reflected by pristane phytane ratios the abundance of terpenoid biomarkers indicates the predominance of gymnosperms over angiosperms which is consistent with palynomorphic spectra dominated by pollen of the sequoia taxodium metasequoia plant community rather than by angiosperms evidence is also provided that the content of land plant derived biomarkers and the preservation of plant tissue is controlled by the input of resin rich decay resistant conifers sections of the seam characterized by a high degree of gelification of humotelinite gelification index show high contents of hop 17 21 ene but low hopane concentrations the results suggest that the gelification of plant tissue may be governed by the activity of anaerobic rather than aerobic bacteria despite the minor variation in the proportions of gymnosperms versus angiosperms in the peat forming vegetation a general influence of the floral assemblage on carbon isotopic composition of the coals 13c 25 3 to 27 0 is proposed carbon cycling during biogeochemical decomposition of plant tissue by bacteria is assumed to affect the 13c value of the lignite petrographic and geochemical data of gelified and ungelified fossil wood provide evidence that gelification may be governed by microorganisms e g anaerobic bacteria different from those responsible for decreasing cellulose contents during early diagenetic aerobic degradation of wood based on the molecular composition of terpenoid biomarkers the wood fragments are identified as derived from gymnosperms the relative proportions of saturated versus aromatic hydrocarbon fractions of fossil gymnosperms display a general tendency towards lower values in gelified wood remains this indicates that bacteria involved in gelification of plant tissue may also be involved in aromatisation of diterpenoid hydrocarbons the chemotaxonomical classification of the macrofossils as gymnosperms is corroborated by the mean carbon isotopic compositions of the macrofossils 13c 24 5 and the extracted cellulose 13c 22 0 the higher isotopic difference of about 2 5 between cellulose and fossil wood compared to that found in modern trees can most probably be explained by the smaller effect of 13c discrimination for cellulose when compared with wood during decomposition chem geol 158 1999 121 compared with the coals the 13c values of wood and extracted cellulose are affected to a minor extent by microbial activity

mechanisms setting the strength of orographic rossby waves across a wide range of climates in a moist idealized gcm abstractorographic stationary rossby waves are an important influence on the large scale circulation of the atmosphere especially in northern hemisphere winter changes in stationary waves with gl

comparative study of serbian miocene coals insights from biomarker composition abstract the origin of the organic matter om and the characteristics of the paleoenvironment of serbian brown coals covering a time span from the lower to the upper miocene were evaluated and compared based on comprehensive petrological and biomarker analyses investigated coals are typical humic coals peat forming vegetation is characterized by abundant decay resistant gymnosperm coniferous plants followed by variable amount of angiosperms coal forming plants belonged to the gymnosperm families taxodiaceae podocarpaceae cupressaceae araucariaceae phyllocladaceae and pinaceae peatification proceeded in fresh water environment under variable eh settings from anoxic to slightly oxic condition upper miocene lignites were formed in neutral to slightly acidic environment whereas lower and middle miocene coals were deposited under neutral to slightly alkaline and more reductive conditions which is the result of calcium rich surface waters derived from the surrounding jurassic to cretaceous calcareous country rock and higher water column level diagenetic changes of the om were governed by bacterial activity rather than thermal alteration biomarker pattern does not significantly differ in serbian coals of different ages the main differences between upper middle and lower miocene coals are expressed by higher gelification index gi proxy ratio p aq n c 23 n c 27 n c 31 and pimarane 16 h phyllocladane ratio as well as lower relative abundance of c 31 r hopane of the latter one om of lower miocene coals is more mature corresponding to immature early mature stage huminite vitrinite reflectance 0 45 whereas om of upper miocene lignites is in immature diagenetic phase huminite reflectance 0 3 consequently higher gelification of lower miocene coals is probably an effect of higher rank however high humidity wet climate and low acidity within the mire could not be excluded a good correlation between biomarker parameters and paleoclimate data is observed indicating that biomarker patterns represent a valuable tool that reflect even slight paleoclimate changes in serbia during miocene

petrological and organic geochemical properties of lignite from the kolubara and kostolac basins serbia implication on grindability index abstract the influence of different coal lithotypes on grindability has been investigated using lignite from two of the most important upper miocene lignite basins in serbia kolubara and kostolac yellow xylite rich types demonstrated the most negative impact on hardgrove grindability index hgi all different types of xylite rich coal as well as total xylite rich coal from the kolubara basin have a negative influence on the grindability properties while only the yellow type of xylite rich coal from the kostolac showed a negative impact on hgi matrix coal does not show a clear effect on hgi a negative correlation between textinite content and hgi is observed in both basins whereas contents of other macerals do not show influence on grindability properties content of total organic carbon demonstrated the negative impact on hgi correlation analysis indicates that the negative impact of the yellow type of xylite rich coal and the sum of total xylite rich coal on the grindability properties partly can be related to content of total organic carbon and high amount of soluble organic matter matrix lithotype does not show any significant correlation with bulk geochemical parameters in both basins the peat forming vegetation of all samples from both basins were dominated by decay resistant gymnosperm coniferous plants belonging to one or several of the families taxodiaceae podocarpaceae cupressaceae araucariaceae phyllocladaceae and pinaceae lignite from the kolubara basin is characterized by a higher contribution of angiosperm vegetation than coal from the kostolac basin peatification of the kolubara coal occurred under more oxic conditions than the kostolac one analysis of biomarkers indicated that the negative impact of all types of xylite rich coal from the kolubara on hgi can be related to the higher proportion of angiosperms abundance of mid chain n alkanes and sesquiterpenoids aromatization of non hopanoid triterpenoids and hopanoids and intense degradation of wood tissues in a more oxic environment the positive impact of matrix coal on hgi in the kolubara samples can be attributed to elevated content of non aromatic hopanoids and low amounts of aromatic non hopanoid triterpenoids and sesquiterpenoids which seems to hinder the grindability properties

average seismic source parameter relations for mid plate earthquakes mid plate earthquakes which are defined as having their epicenters at least 500 km from plate margins represent a small portion of the total global seismicity however because those occurring within continental interiors are characterized by anomalously large damage areas they are of particular interest empirical mb ms and m o data are used to develop scaling relations for mid plate earthquakes from them it is found that the corner period t o2 of their far field displacement spectra varies as the one fourth power of the seismic moment which indicates that average stress drop increases as seismic moment increases by use of savage s 1972 rectangular bilateral dislocation model the derived spectra of mid plate earthquakes yield estimates of fault rupture length and width average fault displacement and source rise time as a function of seismic moment these relations show that large mid plate earthquakes such as the 1886 south carolina and 1811 and 1812 new madrid events do not require large fault rupture length

drowning of a nearshore peat forming environment atane formation cretaceous at asuk west greenland sedimentology organic petrography and geochemistry abstract the cretaceous atane formation nuussuaq basin west greenland is dominated by non marine sandstones shales coals and delta front deposits marine incursions are frequent however and near asuk disko a coal seam is encased in shallow marine deposits notable changes in both petrography and geochemistry occur through the seam at the base and top of the seam the proportions of inertinite and liptinite increase at the expense of the huminite maceral group and within all maceral groups proportions of detrital macerals increase geochemical changes include systematic variations in toc ts n alkane acyclic isoprenoid aromatic hydrocarbon and di and triterpenoid biomarkers which include a number of rearranged hopanes and hopenes and six isomers of 28 30 bisnorhopane the variations reflect diagenetic changes related to the availability of clay as well as changes in depositional environment going from shallow marine conditions through fresh water mire back to open water conditions and to the eventual return of shallow marine conditions shown by the occurrence of delta front deposits containing ophiomorpha nodosa trace fossils c 50 cm above the top of the coal seam

the araripe basin in ne brazil an intracontinental graben inverted to a high standing horst abstract the mesozoic sediments of the araripe basin peak at ca 1000 m more than 500 m above the host precambrian basement this means that an intracontinental graben has been inverted to a topographically high standing horst which raises four fundamental questions 1 where are the inversion structures 2 what is the age of the inversion 3 how can inversion occur in a thick lithosphere 4 what forces are responsible for the inversion here we show that displacement on inverted normal faults increases towards the core of the horst and new reverse faults thrust basement over basin field observations indicate that inversion has occurred on faults striking between nne ssw and e w following the structure of the host basement inversion is reverse dextral in the nne ssw system and reverse sinistral in the ene wsw system this is consistent with the mid atlantic ridge and andean pushes from the tectonic analysis of topography and gravity anomaly the nw se faults seem critical to the inversion although not clearly recognized in the field the inversion of high angle normal faults occurred by oblique slip and injection of clay rich breccias which apparently reduced friction sufficiently to allow for major inversion fault scarps with a prominent topographic expression and faults cutting through colluvium indicate that the latest stage of inversion is quaternary although older inversion episodes are likely the new tectonic data the timing and the stress field altogether indicate that inversion was due to plate wide compression which preferentially concentrated along inherited shear zones and reactivated them to form the main inversion faults of the araripe basin the high degree of inversion in the araripe basin is most likely due to its position at a bend in the major patos shear zone which worked as a restraining bend under the maximum compressive stress acting in ne brazil

a continuing intraplate earthquake sequence near joao câmara northeastern brazil preliminary results shallow seismicity along a well defined section of reactivated precambrian basement near joao c mara brazil 5 5 s 33 7 w has continued since august 1986 a magnitude 4 3 event on 21st august with a decaying aftershock sequence and another main shock aftershock sequence which started in september were followed by a magnitude 5 1 event on 30th november and 11 events of magnitude 4 or above up to february 1987 a network of up to four vertical component short period seismometers with smoked paper recorders has been deployed since late august 1986 several thousand events have been recorded above magnitude 0 and activity was still being recorded about 10 events per day in may 1987 simple velocity structure good transmission and impulsive s arrivals on almost all seismograms combine to facilitate reliable hypocentral locations even for this sparse network and epicenters define a 25 km linear pattern of seismicity with northeasterly strike approximately coincident with a precambrian structural trend a composite fault plane solution shows dextral shear along this strike with a small normal component fault plane solutions and epicenter distribution in northeastern brazil suggest an overall picture of e w regional compression

a petrological and organic geochemical study of permian coal seams east of maracaja south santa catarina parana basin brazil abstract coal samples from the permian rio bonito formation collected from borehole mml 09 east of maracaja south santa catarina parana basin brazil were characterized by petrological vitrinite reflectance measurements maceral analyses and geochemical rock eval total organic carbon toc and gc ms methods the mean vitrinite reflectance values range from 0 73 to 0 87 rrandom indicating a rank level of high volatile b a bituminous the maceral composition showed predominance of vitrinite 49 4 to 61 2 vol and inertinite 9 to 24 5 vol the rock eval analysis presented the following values s1 and s2 ranging from 0 74 to 2 51 mg hc g coal and 34 1 to 108 87 mg hc g coal respectively hydrogen indices between 158 and 240 mg hc g toc and tmax c between 440 and 448 c the toc contents of the coal samples present values ranging from 18 85 to 45 31 wt vitrinite reflectance and rock eval tmax values indicate that the coals are in the beginning of the oil generation window the potential for the formation of liquid hydrocarbons is rather low due to the nature of the humic coal whereas the rank level indicates that generation of gas from the coal has occurred the biomarker analysis using gc ms and gc ms ms allowed the interpretation of the depositional environment and provided another way of determining the degree of maturity of the coals besides vitrinite reflectance and tmax the pristane phytane pr ph ratio is 1 mainly controlled by organic matter type implied suboxic conditions during sedimentation the vitrinite reflectance measurements tmax values and 20s 20s 20r and ratios for c29 regular steranes revealed the marginally mature stage of the organic matter although the distribution of hopanes indicated a mature stage of the organic matter due to the absence of hopanes and predominance of the 22s epimer over the 22r epimer for the hopanes from c 31 to c 35

seismicity and stresses in the brazilian passive margin abstract seismicity and stresses along the brazilian continental margin show different patterns between the northeastern and southeastern regions in the northeastern margin earthquakes tend to occur onshore under a strike slip regime with horizontal compression parallel to the northern coast line in the southeastern margin higher seismicity is observed offshore in areas where the continental crust was highly extended during the south atlantic rifting in the mesozoic three new events in the southeast continental shelf are shown to have reverse faulting mechanisms from waveform modeling of short period teleseismic p waves multiple depth phases reflections from the top and bottom of the water layer and double reflections in the water layer could be identified and better constrained the hypocenters to middle and upper crustal depths in south america models of intraplate stresses caused by plate boundary forces and spreading effects due to the continental oceanic crustal transition indicate higher compressional stresses in the se offshore area as compared with the continental area in agreement with the observed higher seismicity and reverse faulting mechanisms the combination of regional stresses local flexural effects from thick sedimentary loads and a presumably weaker crust from mesozoic thinning explains the main patterns of seismicity in the northeastern and southeastern brazilian margins

the generation of global rotational flow by steady idealized tropical divergence abstract tropical convective heating is balanced on the large scale by the adiabatic cooling of ascent the horizontal divergence of the wind above this heating may be viewed as driving the upper tropospheric rotational wind field a vorticity equation model is used to diagnose this relationship it is shown that because of the advection of vorticity by the divergent component of the flow the rossby wave source can be very different from the simple fd source often used in particular an equatorial region of divergence situated in easterly winds can lead to a rossby wave source in the subtropical westerlies where it is extremely effective this part of the source can be relatively insensitive to the longitudinal position of the equatorial divergence a divergence field which is asymmetric about the equator can lead to a quite symmetric rossby wave source for a steady frictionless flow the rossby wave source averaged over regions within closed streamfunction or absolute vorticity contours is under cert

linear simulation of the stationary eddies in a general circulation model part i the no mountain model abstract the quantitative validity of linear stationary wave theory is examined by comparing the results from a linear primitive equation model on the sphere with the stationary eddies produced by a general circulation model gcm the gcm simulated has a flat lower boundary so that the stationary eddies can be thought of as forced by heating sensible latent and radiative and time averaged transient eddy flux convergences orographic forcing is examined in the second part of this study the distribution of the diabatic heating and transient eddy flux convergences and the zonally symmetric basic state are taken directly from the gcm s climatology for northern winter djf strong rayleigh friction is included in the linear model wherever the zonal mean wind is small as well as near the surface the linear model is found to simulate the stationary eddy pattern of the gcm with considerable skin in both midlatitudes and the tropics some deficiencies include the inaccurate simulation of the upper troposp

diabatic and orographic forcing of northern winter stationary waves and storm tracks abstract in this study a dry global circulation model is used to examine the contributions made by orographic and diabatic forcings in shaping the zonal asymmetries in the earth s northern hemisphere nh winter climate by design the model mean flow is forced to bear a close resemblance to the observed zonal mean and stationary waves the model also provides a decent simulation of the storm tracks in particular the maxima over the pacific and atlantic and minima over asia and north america are fairly well simulated the model also successfully simulates the observation that the atlantic storm track is stronger than the pacific storm track despite stronger baroclinicity over the pacific sensitivity experiments are performed by imposing and removing various parts of the total forcings in terms of the nh winter stationary waves in the upper troposphere results of this study are largely consistent with previous studies diabatic forcings explain most of the modeled stationary waves with orographic

reconstruction of floral changes during deposition of the miocene embalut coal from kutai basin mahakam delta east kalimantan indonesia by use of aromatic hydrocarbon composition and stable carbon isotope ratios of organic matter the distribution of aromatic hydrocarbons and stable carbon isotope ratios of organic matter in a series of nine miocene embalut coal samples obtained from nine coal seams of kutai basin east kalimantan indonesia were studied the rank of the embalut coals ranged from lignites to low rank sub bituminous coals 0 36 0 50 rr based on measurements of huminite reflectance the aromatic hydrocarbon fractions of all coal samples were dominated by cadalene in the lower boiling point range and picene derivatives in the higher boiling point range of the gas chromatograms cadalene can be attributed to the contribution of dipterocarpaceae and various hydrated picenes to the contribution of additional angiosperms to the coal forming vegetation the picenes originate from alpha and beta amyrin however in some coal samples minor amounts of simonellite and retene were also detected which argues for an additional contribution of gymnosperms conifers to coal forming vegetation preferentially in the middle miocene and at the beginning of the late miocene the results of stable carbon isotope ratios d 13

intraplate earthquake swarm in belo jardim ne brazil reactivation of a major neoproterozoic shear zone pernambuco lineament summary intraplate earthquakes in stable continental areas have been explained basically by reactivation of pre existing zones of weakness stress concentration or both zones of weakness are usually identified as sites of the last major orogeny provinces of recent alkaline intrusions or stretched crust in ancient rifts however it is difficult to identify specific zones of weakness and intraplate fault zones are not always easily correlated with known geological features although northeastern brazil is one of the most seismically active areas in the country magnitudes 5 roughly every 5 yr with hypocentral depths shallower than 10 km and seismic zones as long as 30 40 km no clear relationship with the known surface geology can be usually established with confidence and a clear identification of zones of weakness has not yet been possible here we present the first clear case of seismic activity occurring as reactivation of an old structure in brazil the pernambuco lineament a major neoproterozoic shear zone the 2004 earthquake swarm of belo jardim magnitudes up to 3 1 and the recurrent activities in the nearby towns of sao caetano and caruaru magnitudes up to 4 0 and 3 8 show that the pernambuco lineament is a weak zone a local seismic network showed that the belo jardim swarm of 2004 november occurred by normal faulting on a north dipping e w oriented fault plane in close agreement with the e w trending structures within the pernambuco lineament the belo jardim activity was concentrated in a 1 5 km e w by 2 km downdip fault area and average depth of 4 5 km the nearby caruaru activity occurs as both strike slip and normal faulting also consistent with local structures of the pernambuco lineament the focal mechanisms of belo jardim caruaru and s caetano indicate e w compressional and n s extensional principal stresses the ns extension of this stress field is larger than that predicted by numerical models such as those of coblentz richardson and we propose that additional factors such as flexural stresses from the nearby sergipe alagoas marginal basin could also affect the current stress field in the pernambuco lineament

the intraplate porto dos gauchos seismic zone in the amazon craton brazil abstract the largest earthquake observed in the stable continental interior of the south american plate occurred in serra do tombador mato grosso state brazil on january 31 1955 with a magnitude of 6 2 mb since then no other earthquake has been located near the 1955 epicentre however in porto dos gauchos 100 km northeast of serra do tombador a recurrent seismicity has been observed since 1959 both serra do tombador and porto dos gauchos are located in the phanerozoic parecis basin two magnitude 5 earthquakes occurred in porto dos gauchos in 1998 and 2005 with intensities up to vi and v respectively these two main shocks were followed by aftershock sequences lasting more than three years each local seismic stations have been deployed by the seismological observatory of the university of brasilia since 1998 to study the porto dos gauchos seismic zone pgsz a local seismic refraction survey was carried out with two explosions to help define the seismic velocity model both the 1998 and 2005 earthquake sequences occurred in the same wsw ene oriented fault zone with right lateral strike slip mechanisms the epicentral zone is in the parecis basin near its northern border where there are buried grabens generally trending wnw ese such as the deep mesoproterozoic caiabis graben which lies partly beneath the parecis basin however the epicentral distribution indicates that the 1998 and 2005 sequences are related to a n60 e fault which probably crosses the entire caiabis graben the 1955 earthquake despite the uncertainty in its epicentre does not seem to be directly related to any buried graben either the seismicity in the porto dos gauchos seismic zone therefore is not directly related to rifted crust the probable direction of the maximum horizontal stress near porto dos gauchos is roughly e w consistent with other focal mechanisms further south in the pantanal basin and paraguay but seems to be different from the nw se direction observed further north in the amazon basin the recurrent seismicity observed in porto dos gauchos and the large 1955 earthquake nearby make this area of the parecis basin one of the most important seismic zones of brazil

the regional intraplate stress field in south america a compilation of lithospheric stress directions for continental south america and the inferred major patterns of the regional intraplate stress field are presented stress orientations are based primarily on earthquake focal mechanisms and quaternary fault slip inversion published in the literature four new focal mechanisms based on short period p wave modeling and selected centroid moment tensor solutions published by u s geological survey consistent with p wave first motions at south american and other world wide standard seismograph network stations are also included in the data base the observed patterns of intraplate stresses may be useful in constraining numerical models of the plate driving forces in the south american plate in the andean plateau altitudes greater than 3000 m n s extensional stresses predominate e w compressional stresses are observed in the sub andean and platform regions extending up to about 1000 km east of the andes the maximum horizontal stress shmax is uniformly oriented in the e w direction throughout western south america averages of the shmax direction at grid points spaced 2 5 o were taken as representing the regional field the e w direction of this regional field is not affected by the change of strike of the andean chain nor by the contact of a flat subducted slab underneath the regional shmax direction is oriented 15 o more clockwise than the direction of the nazca plate convergence the difference between the regional shmax orientations and the absolute plate motion may be only about 6 o this may indicate that contact forces with the nazca plate may not be the only major contributor to the intraplate stresses in western south america the eastern limit of this andean stress province seems to coincide with aseismic regions in the upper amazon basin and in the paraml basin in the central amazonian region seismicity and stress data suggest a seismic province with n s compressional stresses the origin of these stresses is not yet clearly understood but could possibly be related to lower crustal loading along the middle amazon basin in northeastern brazil seismicity is characterized by upper crustal strike slip earthquakes bordering the potiguar marginal basin a model is proposed for this region in which the stress field is the result of a superposition of regional e w compressional stresses and local extensional stresses oriented perpendicular to the continental margin possibly related to density contrasts and sediment loading in the continental shelf

seismicity in north eastern brazil fractal clustering and the evolution of the b value summary we analyse a catalogue of earthquakes recorded near joao camara brazil an intraplate area with a simple velocity structure and low attenuation the evolution of seismicity is characterized by the seismic b value and the fractal dimension of earthquake epicentre locations measured from sliding 100 event windows the events are divided into a number of spatial clusters using a nearest centroid sorting technique and two of these clusters are examined in detail one cluster characterized by intense activity shows a clear negative correlation between b value and fractal dimension of epicentre locations as has been predicted from simple mechanical models a second cluster shows a weak positive correlation and it is suggested that this might be explained in terms of fluid flow in the fault zone

parameters determining the carbon isotopic composition of coal and fossil wood in the early miocene oberdorf lignite seam styrian basin austria abstract petrographical and geochemical data of gelified and ungelified fossil wood from the early miocene oberdorf lignite seam styrian basin austria provide evidence that the early diagenetic aerobic degradation of wood by fungi may be followed by further decomposition under reducing conditions by the activity of anaerobic bacteria based on the molecular compositions of terpenoid hydrocarbons the wood fragments in the lignite are identified as gymnosperms this result is corroborated by the mean isotopic composition 13c 24 2 of the macrofossils the isotopic difference between fossil wood and extracted cellulose of most samples 3 9 2 5 is higher than in modern trees which can be explained by the smaller effect of 13c discrimination during decomposition of cellulose when compared with wood the mean carbon isotope values found for gymnosperms and coals 24 2 and 24 7 respectively confirm the results from biomarker analyses indicating that the peat forming vegetation of the oberdorf seam was dominated by gymnosperm taxa minor variation in the relative contributions of gymnosperms and angiosperms to coal deposition is of negligible influence on the isotopic composition of the coals cross correlations between 13c of the coals soluble organic matter yield and the proportions of liptinite macerals of higher plant origin imply that the carbon isotopic composition may be affected by the contents of plant lipids because of their 13c values ranging from 5 to 10 less than whole plant tissue values an isotopic shift of the coals towards more negative values due to the activity of prokaryotes i e anaerobic bacteria in organic matter degradation is proposed the results obtained from the early miocene oberdorf lignite indicate that the carbon isotope ratios of the coals are primarily affected by varying contributions of different parts of whole plant tissue due to their different isotopic and molecular compositions e g epicuticular leaf waxes resins wood and their different decay resistance against the early diagenetic changes involved in organic matter decomposition carbon cycling during anoxic decomposition of plant derived organic matter is assumed to affect the 13c values of coal 13c values of wood and extracted cellulose are affected only to a minor extent

influence of floral assemblage facies and diagenesis on petrography and organic geochemistry of the eocene bourgas coal and the miocene maritza east lignite bulgaria abstract numerous differences in the petrography and organic geochemistry of two tertiary low rank coal deposits of bulgaria formed within comparable depositional environments are outlined different floral assemblages are indicated as the main sources of organic matter for the eocene bourgas sub bituminous coals a warm climate plant community dominated by angiosperms is reflected in the biomarker composition whereas a coniferous flora was the main source of the resinous organic matter of the miocene maritza east lignite the results are in agreement with palaeobotanical data these differences in the peat forming vegetation of the paleogene compared to the neogene of bulgaria are attributed to decreasing temperature during the tertiary the abundance of resinous compounds relative to lipids from plant waxes long chain n alkanes as well as the preservation of plant tissue are mainly controlled by gymnosperm angiosperm ratios pristane phytane and diasterenes sterenes ratios reflect variations in redox conditions and the ph of the depositional environments caused by eustatic sea level changes freshwater inflow or varying ground water table changing eh and ph values are associated with differences in microbial activity controlling the extent of gelification of plant tissue bacteria most probably contributed to the aromatisation of triterpenoids in the mire enhanced thermal maturation of organic matter during diagenesis is reflected in higher contents of n alkanes and the presence of alkyl naphthalenes in the bourgas coals alkyl naphthalenes are thought to have been formed from pentacyclic triterpenoids rather than from resinous compounds

fault plane solutions of intraplate earthquakes in brazil some constraints on the regional stress field abstract determination of intraplate stress fields is fundamental for a better understanding of the forces driving the plates in the south american plate few earthquakes away from the plate boundaries have been recorded by enough stations to have the nodal planes well determined the fault plane solutions of four recent events in central and northern brazil were determined these solutions were compared with previously determined solutions of other events in central and southeast brazil a statistically reliable estimation of the stress field for all of brazil is not yet possible on the basis of these data near the atlantic coast however the data are compatible with a regional stress field with the maximum compressive stress oriented parallel to the expected direction of ridge push or of south america s absolute plate motion mendiguren and richter 1978 farther to the west the stress field changes the direction of the maximum compressive stress seems to be aligned n s rather than e w almost all earthquakes analysed show reverse or strike slip focal mechanisms one event in central brazil however shows normal faulting thus the stress field in brazil is certainly not uniform and in some areas local sources of stress may predominate over regional fields

an analysis of equatorial pacific sea surface temperature anomaly experiments in general circulation models with and without mountains abstract perpetual january experiments have been performed using versions of the ncar community climate model ccm with and without mountains features of the mean simulations of the no mountains experiment are compared with those of the standard ccm the mountains experiment the stationary waves in the no mountains experiment have smaller amplitudes than those in the mountains case especially for zonal wavenumbers 2 and 3 the mean zonal wind in the no mountains case also has weaker horizontal gradients than in the mountains case the response of these two versions of the ccm to equatorial pacific sea surface temperature sst anomalies is investigated two anomalies are considered for each model configuration differences in the responses of the two models to the same anomalous forcing are discussed the northern hemisphere midlatitude response of the no mountains model has nearly the same spatial scale as that of the mountains model but details of the shape of the response pattern a

the 1986 1988 intraplate earthquake sequence near joao câmara northeast brazil evolution of seismicity abstract the 1986 1988 intraplate earthquake sequence near joao c mara 5 5 s 35 7 w has been among the most significant in northeast brazil this century some 14 000 events were recorded in the 18 months from august 1986 including fifteen above magnitude 4 0 and one of 5 1 4000 buildings were damaged a local network of four portable seismographs was operated during most of the period augmented by a nine station telemetric network between may 1987 and april 1988 the temporal and spatial distribution of this seismicity is examined and determination of unusually good hypocentres is made possible by the simple velocity structure good signal transmission and impulsive p and s arrivals on most seismograms activity has been closely confined to a 28 km linear zone with a strike of 040 except for some small events along a parallel zone displaced laterally by 12 km neither zone has been related to any surface feature some unusual characteristics have raised concern about possible future seismicity the largest event occurred four months after the onset of activity and after several weeks of relative quiescence a 5 km intermediate section of the inferred fault has so far experienced only a few very small events

organization of storm track anomalies by recurring low frequency circulation anomalies abstract from previous studies it is known that anomalous momentum fluxes by bandpass eddies are important in maintaining long lasting tropospheric flow anomalies evidence is presented that suggests that these anomalous fluxes do not occur at random but happen because the structure of storm track activity is modified by the presence of prominent low frequency large scale circulation anomalies this behavior is noted in an extended integration of a perpetual january simulation with a general circulation model gcm because nonlinear feedbacks between low and high frequency variability make it difficult to establish causal relationships between these two ranges of variability a model is constructed that approximates the storm track activity that would be expected to accompany a given low frequency without including the feedback of the high frequencies onto the low frequency state this model is based on the linearized primitive equations and uses a series of short integrations from random initial condi

petrological palynological and geochemical characteristics of eureka sound group coals stenkul fiord southern ellesmere island arctic canada abstract late paleocene early eocene coal bearing strata are widespread across the canadian arctic archipelago laterally continuous seams of substantial thickness are present in the iceberg bay formation eureka sound group at stenkul fiord ellesmere island sixty four coal seams with a cumulative thickness of 53 m of coal occur in a 450 m sequence the investigation of the composite section is based on examination of 19 samples from seams thicker than 1 m and 7 samples from marker seams used for correlation purposes the coals consist predominantly of wood derived huminite macerals 79 98 vol structured huminite macerals are dominant in the top part of the section whereas detrital components are abundant in the lower part the liptinite fraction is dominated by sporinite and cutinite 1 9 vol inertinite content is very low except at the base of the section 0 14 vol reflectances determined on eu ulminite 0 36 0 43 r o geochemical parameters and thermal alteration indices indicate that the coals are of lignite to subbituminous rank the dominance of diterpanes and the abundance of taxodiaceae and pinaceae pollen suggest that most of the organic matter is of gymnospermous origin pinaceae pollen is abundant in the lower part of the section and taxodiaceae is abundant in the upper part the abundance of angiosperm pollen in most of the section suggests however that angiospermous plants were significant members of the flora the depositional environment for the iceberg bay formation coals at stenkul fiord is that of forested swamps on an alluvial plain pollen assemblages indicate a late paleocene early eocene age for the section and a temperate moist climate