the guadalupian permian kamura event in european tethys article i nfo in order to document paleoenvironmental conditions of the equatorial western paleo tethys during the late middle permian prior to the end guadalupian mass extinction chemostratigraphic analysis using stable carbon isotopes was conducted for the guadalupian rocks at brusane in the velebit mtn central croatia by analyzing 72 carbonate samples of the capitanian upper guadalupian velebit formation we found an interval with unusually high 13 ccarb values 4 to 6 in the ca 150 m thick yabeina fusuline zone the present find clarifies that the primary productivity and burial rate into the sediments were considerably high during the capitanian in westernmost paleo tethys this chemostratigraphic signal is properly correlated with the kamura event detected in a mid panthalassan paleo atoll limestone in japan the present results identify the capitanian kamura event for the first time in european paleo tethys on the opposite side of the globe from the mid panthalassan paleo seamount and prove the global context of the event as well as its utility in chemostratigraphic correlation in order to enhance bioproductivity on a global scale the increase in nutrient supply is inevitable in addition to riverine run off from pangea active oceanic circulation in particular upwelling of deep sea water enriched in nutrients was likely vital both in panthalassa and paleo tethys the extinction of some guadalupian fauna in particular photosymbiotic community large tested fusulines large bivalves rugose corals was likely related to a temporary cooling coupled with eutrophication in low latitude shallow marine environments of paleo tethys and panthalassa

early eocene carbon isotope excursions evidence from the terrestrial coal seam in the fushun basin northeast china a series of transient global warming events between 56 and 50 ma are characterized by a pronounced negative carbon isotope excursion cie however the documents of these hyperthermals such as eocene thermal maximum 2 and h2 events have come chiefly from marine sediments and their expression in terrestrial organic carbon is still poorly constrained here we yield a high resolution carbon isotope record of terrestrial organic material from the fushun basin which displays four prominent cies with magnitudes larger than 2 5 based on age constraint and comparisons with deep sea records our data provide the first evidence of the four hyperthermals in coal seams and suggest a global significance of these events moreover the difference of cie magnitudes between marine and terrestrial records shows a significant linear correlation with the marine carbonate cie implying that these events are likely attributable to recurring injections of 13c depleted carbon from submarine methane hydrates and or permafrost

westerly wind events in the tropical pacific 1986 95 abstract based on examination of 10 yr of 10 m winds and wind anomalies from european centre for medium range weather forecasts ecwmf analysis definitions for westerly wind events wwes of eight different types are proposed the authors construct a composite for each type of event show that a simple propagating gaussian model satisfactorily describes the evolution of zonal wind anomaly for each type of event and determine the scales of each composite event by fitting the model to each composite the authors discuss the wwes that occurred during the tropical oceans global atmosphere coupled ocean atmosphere response experiment toga coare intensive observing period iop and show the extent to which these composite events are able to reproduce the major westerly wind features of the iop the frequency of occurrence of each type of wwe for each year of this record and by calendar month are described the authors find several types of events are negatively correlated with the annual mean troup souther

decoupling δ13c response to palaeoflora cycles and climatic variation in coal a case study from the late permian bowen basin queensland australia abstract the late permian coal measures of the bowen basin australia express both environmental and climatic changes that occurred prior to the permian triassic p t boundary in order to decouple the influence of environmental factors salinity ph base level and temperature from depositional and climatic factors atmospheric co2 in organic 13c a high resolution study was performed on 24 coal seams total 24 6 m in the late permian stratigraphy in the northern bowen basin the late permian stratigraphy of the bowen basin records a transition from deltaic and lacustrine conditions within the tinowan formation and black alley shale formation to fluvial deposition in the kaloola and bandanna formations intermittent volcanism is recorded by tuff layers during periods of peat accumulation variations of coal lithotypes were recorded and formed the basis of sampling for petrography and isotope analysis coal samples were etched to expose cellular anatomy and systematically identified to recognise palaeoflora assemblages when observed within seam 13c of the coal varied cyclically 13c enriched depleted enriched as a response to environmental changes expressed in palaeoflora communities the total range of 13c was 26 6 to 21 9 the overall trend of 13c progresses to increasing 13c enrichment corresponding with dull lithotypes rich in inertinite which indicate fluctuations in base level the 13c enrichment peaks at 22 5 within the kaloola member and shifting rapidly toward a depletion maximum 26 6 of 13c in the upper bandanna formation prior to the p t boundary these changes are expressed in palaeoflora communities where ecosystems shifted from dominant glossopteris flora to climax community flora including palaeosmunda cycadales and ginkgo suited to temperate early mesozoic climates the results of this study represent an insight into the effects of environmental variables on 13c uptake of plants the identification of flora within coal gives an insight into palaeowetland evolution and can be partnered with classic petrographical techniques for integrated analysis in coals both the geochemistry and the anatomical aspects of coal represent an important tool for future palaeowetland research

seasonal fluctuations of the surface north equatorial countercurrent necc across the pacific basin 1 based on multisatellite derived sea surface current sea surface height anomaly and geostrophic current data the annual variability of the surface necc across the pacific basin is investigated inferred from the surface current data the necc axis east and west of the dateline moves northward along its pathway in the latter half of a year and the first half of a year respectively the sea surface height anomaly in the necc region and the meridional movement of necc are well reproduced by a linear wind driven first mode baroclinic rossby wave model model experiments by setting the phase speed of baroclinic rossby wave or the ekman pumping to zero in different regions are carried out to clarify the influence of rossby wave and local ekman pumping on the movement of necc east of the dateline both ekman pumping and rossby wave are important in determining the northward movement of the necc axis however the necc axis west of the dateline moves northward primarily due to the westward transmission of positive sea surface height anomalies or downwelling rossby waves that originate in the east of the dateline the local ekman pumping plays a minor role in controlling the migration of the necc axis west of the dateline

sst anomalies of enso and the madden julian oscillation in the equatorial pacific this study explores whether anomalies of sea surface temperature sst in the equatorial pacific during warm events of el nino southern oscillation enso are related to the madden julian oscillation mjo an index is derived from surface wind data of a global model reanalysis to measure forcing of oceanic kelvin waves by wind stress associated with the mjo this kelvin wave forcing index of the mjo is used to relate interannual anomalies in seasonal activity of the mjo to interannual anomalies in equatorial sst for the 1980 99 time period evidence is found showing that during enso warm events stronger kelvin wave forcing in the western pacific precedes greater sst anomalies in the eastern pacific by 6 12 months no such evidence however can be found for the period of 1950 79 the result suggests that during enso warm events amplitudes of sst anomalies in the eastern pacific can be affected by the mjo at least for the 1980 99 period through its seasonal activity of kelvin wave forcing a possible mechanism for such an mjo enso relationship is described how enso prediction can be benefited from the precursory signals of the mjo is discussed

sediment deformation and hydrogeology of the nankai trough accretionary prism synthesis of shipboard results of odp leg 131 the main objective of leg 131 was to provide data on the deformational processes and associated hydrogeology of the nankai prism toe drilling succeeded for the first time in the history of ocean drilling in penetrating the complete sedimentary sequence to basaltic basement reaching 1327 mbsf metres below seafloor with good core recovery 55 excellent correlation of the lithology and structure including the frontal thrust and the decollement with seismic reflection images was also determined bedding dips faults and shear bands analyzed in the cores confirm the pattern of deformation to be mainly due to nw se shortening as expected from the plate tectonic convergence vector below the decollement no significant deformation features were observed indicating that the decollement is a sharp discontinuity in stress transmission physical properties data show major discontinuities at the decollement notably an increase in porosity below the later this may indicate excess pore pressure in the subducted section and decollement zone a less marked increase in porosity below the frontal thrust may reflect the youthfulness of this feature attempts to make downhole measurements were severely hampered by unstable hole conditions but useful constraints have been placed on the thermal regime and some calibration of laboratory physical properties toin situ conditions has been provided andin situ stress and pore pressure were measured in the uppermost sediments evidence of channelized fluid flows is inconclusive no sharp geochemical signatures or unequivocal geochemical anomalies indicative of channelized fluid flow were found thermal measurements are not significantly different from those predicted by a purely conductive heat flow model a signature of low chloride pore water near the decollement may partly be related to smectite diagenesis but may also be due to episodic fluid flow events we conclude that dewatering probably occurred dominantly through diffuse flow throughout the accreted sediments at this site

the middle miocene yallourn coal seam the last coal in australia abstract the 100 m thick middle miocene yallourn brown coal seam was the last of the major latrobe valley group seams to form in the gippsland basin southeastern australia and the final major coal to form in australia coal deposition coincided with the middle miocene climatic optimum during this warm period of relatively high sea levels high water tables and relatively high subsidence rates a 565 km 2 area of alternating eutrophic and ombrogenous peat swamp developed at the western end of the latrobe valley to form the yallourn seam stratigraphic units of the seam contain a high sclerophyll plant component and abundant charcoal suggesting seasonal dry periods alternated with wet warm conditions characterised by abundant rushes and dense kauri forests iron content in parts of the yallourn seam is relatively high and a strong correlation exists between the iron distribution and the abundance of proteoid roots mainly proteaceae an indicator of seasonal dry periods the contemporaneous carbonates of the wuk wuk marl were deposited in a high productivity upwelling warmer water subtropical environment a new carbon isotope profile at 1 m intervals through the yallourn seam shows a poor relationship between 13 c isotopes and coal colour but some correlation with gymnosperm abundance the 13 c record also correlates well with long term secular changes in climate the presence of global carbon maxima cm2 cm4 and with the deep sea 13 c marine organic record thick coal seam development ended near the end of the middle miocene climatic optimum the termination of coal seam deposition in latrobe valley was primarily the result of tectonic compression uplift and development of adjacent highland relief and erosion at the end of the miocene

on the high heat flow in the nankai trough area a simulation study on a heat rebound process abstract a concentration of high heat flow as high as 120 160 mw m2 has been observed in the nankai trough off southwest japan where the philippine sea plate shikoku basin is subducting beneath the japanese landmass we interpret this high heat flow in the subduction zone as being caused by the recovery of conductive heat flow to the theoretically expected value for the young shikoku basin lithosphere after cessation of hydrothermal heat exchange through sediment the thickening sedimentary cover suppresses the rapid heat exchange between basement and sea water whereas the topmost part of the basement allows a hydrothermal circulation within it to pump up heat from the hot plate to the sediment cover we propose to call this process heat rebound numerical simulation shows that significant heat flow recovery can occur and is largely influenced by the sedimentation rate we believe that the high heat flow in the nankai trough is one of the heat rebound cases however rapid sedimentation in the trough also indicates that heat flow recovery expected by the simulation is not large enough to explain the trough high heat flow by the heat rebound process only

propagation mechanisms for the madden julian oscillation the madden julian oscillation mjo is examined using 20 years of outgoing long wave radiation and national centers for environmental prediction national center for atmospheric research re analysis data two mechanisms for the eastward propagation and regeneration of the convective anomalies are suggested the first is a local mechanism operating over the warm pool region at the phase of the mjo with a dipole structure to the convection anomalies there is enhanced tropical convection over the eastern indian ocean and reduced convection over the western pacific over the equatorial western indian ocean the equatorial rossby wave response to the west of the enhanced convection includes a region of anomalous surface divergence associated with the anomalous surface westerlies and pressure ridge this lends to suppress ascent in the boundary layer and shuts off the deep convection eventually leading to a convective anomaly of the opposite sign over the indonesian sector the equatorial kelvin wave response to the east of the enhanced convection includes a region of anomalous surface convergence into the anomalous equatorial surface easterlies and pressure trough which will tend to favour convection in this region the indonesian sector is also influenced by an equatorial rossby wave response of opposite sign to the west of die reduced convection over the western pacific which also has a region of anomalous surface convergence associated with its anomalous equatorial surface easterlies and pressure trough hence convective anomalies of either sign tend to erode themselves from the west and initiate a convective anomaly of opposite sign via their equatorial rossby wave response and expand to the east via their equatorial kelvin wave response the second mechanism is global involving an anomaly completing a circuit of the equator enhanced convection over the tropical western pacific excites a negative mean sea level pressure m s l p anomaly which radiates rapidly eastward as a dry equatorial kelvin wave at approximately 35 m s 1 over the eastern pacific it is blocked by the orographic barrier of the andes and central america for several days before propagating through the gap at panama after rapidly propagating as a dry equatorial kelvin wave over the atlantic the m s l p anomaly is delayed further by the east african highlands before it reaches the indian ocean and coincides with the development of enhanced convection at the start of the next mjo cycle

geostrophic circulation in the tropical north pacific ocean based on argo profiles absolute geostrophic currents in the north pacific ocean are calculated from the newly gridded argo profiling float data using the p vector method for the period of 2004 11 the zonal geostrophic currents based on the argo profile data are found to be stronger than those based on the traditional world ocean atlas 2009 woa09 data a westward mean geostrophic flow underneath the north equatorial countercurrent is identified using the argo data which is evidenced by sporadic direct current measurements and geostrophic calculations in history this current originates east of the date line and transports more than 4 x 10 6 m 3 s 1 of water westward in the subsurface northwestern tropical pacific ocean the authors name this current the north equatorial subsurface current the transport in the geostrophic currents is compared with the sverdrup theory and found to differ significantly in several locations analyses have shown that errors of wind stress estimation cannot account for all of the differences the largest differences are found in the area immediately north and south of the bifurcation latitude of the north equatorial current west of the date line and in the recirculation area of the kuroshio and its extension where nonlinear activities are vigorous it is therefore suggested that the linear dynamics of the sverdrup theory is deficient in explaining the geostrophic transport of the tropical northwestern pacific ocean

response of carbon isotopic compositions of early middle permian coals in north china to palaeo climate change abstract to investigate the magnitude to which the carbon isotopic ratio 13c varies in coals in response to their contemporary terrestrial environment the early middle permian huainan coals including coals from the shanxi formation lower shihezi formation and upper shihezi formation in north china were systematically sampled a 2 5 variation range of 13c values 25 15 to 22 65 was observed in huainan coals with an average value of 24 06 as coal diagenesis exerts little influence on carbon isotope fractionation 13c values in coals were mainly imparted by those of coal forming flora assemblages which were linked to the contemporary climate the 13c values in coals from the shanxi and lower shihezi formations are variable reflecting unstable climatic oscillations heavy carbon isotope is enriched in coals of the capitanian upper shihezi formation implying a shift to high positive 13c values of coeval atmospheric co2 notably our study provides evidence of the kamura event in the terrestrial environment for the first time

westward migration of the izu bonin trench northward motion of the philippine sea plate and their relationships to the cenozoic tectonics of japanese island arcs abstract the essential elements in the understanding of the cenozoic island arc tectonics of the japanese islands came from reconstructing the paleo position of the plate boundaries and estimating the change in the philippine sea plate motion by using the 2nd law of the convergence rate of plates it was estimated that the izu bonin trench wandered around 400 km east from its present position during the paleogene and migrated westward thereafter island arc tectonism is related to the convergence rate of plates 1st law of the convergence rate of plates hence the changes in the philippine sea plate motion was examined by compiling paleomagnetic data as a result the main events of the cenozoic tectonics of japan were well explained by the change in the position of the plate boundaries and the change in motion of the philippine sea plate

a mesoscale eddy pair southwest of taiwan and its influence on deep circulation 1 a pair of mesoscale eddies namely an anticyclonic eddy ae and a cyclonic eddy ce generated southwest of taiwan was investigated using long term moored observations augmented with satellite and reanalysis data ae ce increased the upper ocean current to 100 cm s 50 cm s and generated temperature anomaly t up to 7 5 c 3 0 c the vertical structure of ae presented a phase difference between t and velocity with the core of t located south of the zero velocity line this phase difference induced a 28 5 12 0 tw 1 tw 1012 w westward eddy heat transport southwest of taiwan ae also presented strong nonlinearity in the upper ocean and yielded an annual mean volume transport of 0 86 0 15 sv energy analysis showed that both baroclinic and barotropic instabilities were important for the generation and growth of the eddy pair and contribution from wind work was relative small in the deep sea ae ce intensified the deep currents and generated large positive negative t the deep and surface currents flowed in opposite directions during the eddy events which is consistent with the interpretation that the eddy pair is dominated by the first baroclinic mode the observed deep penetrating eddy pair could greatly influence the deep circulation of the northeastern south china sea

thermal effects of hydrothermal circulation and seamount subduction temperatures in the nankai trough seismogenic zone experiment transect japan 1 we examine the thermal effects of seamount subduction seamount subduction may cause transient changes in oceanic crust hydrogeology and plate boundary fault position prior to subduction seamounts provide high permeability pathways between the basaltic crustal aquifer and overlying ocean that can focus fluid flow and efficiently cool the oceanic crust as the seamount is subducted the high permeability pathway is closed shutting down the advective transfer of heat if significant fluid flow occurs it would be restricted after seamount subduction and would result in a redistribution of heat warming the trench and cooling landward parts of the system additionally subducting seamounts can influence the position of the plate boundary fault that has thermal consequences by locally controlling the proportions of incoming sediment that subduct and accrete shifting the decollement to the seafloor at the trench in the wake of seamount subduction causes limited cooling focused at the toe of the margin wedge we apply these features of seamount subduction to a thermal model for the nankai trough seismogenic zone experiment transect on the margin of japan models with hydrothermal circulation provide an explanation for anomalously high surface heat flux observations near the trench they yield temperatures of 100 c 295 c for the rupture area of the 1944 tonankai earthquake temperatures in the region of episodic tremor and slip are estimated at 290 c 325 c 70 c cooler than a model with no fluid circulation

modeling thermal history of subducting crust in nankai trough constraints from in situ sediment temperature and diagenetic reaction progress 1 values of borehole temperature and smectite in illite smectite mixed layer clay provide important information about the basal heat flux history of the nankai trough subduction zone numerical simulations of sediment accumulation heat conduction and illite smectite diagenesis permit comparisons of various thermal history scenarios for odp site 1173 in our preferred models basal heat flux during the first 10 ma of sedimentation was near typical values for conductively cooling crust during the last 5 ma basal heat flux was higher than expected the anomalous heat flux was likely influenced by both off axis volcanism and hydrothermal circulation

petrologic and stable isotopic study of the walloon coal measures surat basin queensland peat accumulation under changing climate and base level abstract the late jurassic walloon subgroup recently dated as oxfordian is a productive subbituminous coal seam gas source in the surat basin and can be subdivided from bottom to top into the taroom coal measures the tangalooma sandstone the lower and upper juandah coal measures which have different coal character the lower taroom coals are commonly thick associated with sandstones and interpreted to form as base level is rising creating sodden anoxic conditions for peat accumulation the middle tangalooma to lower juandah contains fewer and thinner coals and transitions upwards from a sandstone to siltstone dominated sequence responding to inundation with the development of floodplain lakes the strata then coarsen upward in both grain size and coal thickness in the upper juandah coal measures which may be eroded by an overlying unit the springbok sandstone this unconformable surface is basin wide and depending on age can be tied into global changes in climate and base level existing models for peat growth under changing base level and the variability in terms of the conditions of peat formation through time as well as throughout the basin are tested environment of peat deposition and changes therein are investigated by petrographic analysis of the walloon coals coupled with high resolution lithotype logging of core and organic stable carbon isotope analysis fine microlayering and abundance of root suberinite telo and detrovitrinite indicate precursory peat formation in a mostly herbaceous marsh to fen environment in which bigger trees are either infrequent or absent except for the lower seams of the taroom coal measures and the upper seams of the lower juandah coal measures where bright bands are thicker 10 mm and more frequent no extended periods of dehydration oxidation stable carbon isotopes of coal show a distinct positive shift in the lower juandah coal measures that sets in well before the increased inertinite content in the upper juandah coal measures the enrichment in 13 c could be linked to a change in climate during the high stand depositional cycle marking the onset of late stage falling where base level begins to drop later creating exposures and water stress a shift to a less humid climate in the upper juandah coal measures could have favoured the conditions for desiccation mouldering and bush fires which is reflected in the coal s maceral composition the surat basin 13 c isotope trend follows the global trend found in marine carbonate samples from the same age interval that corroborates increasing enrichment towards the top of the coal measures approximately middle oxfordian followed by a shift to more negative compositions which corresponds to the onset of the springbok sandstone deposition on an unconformable surface

late paleozoic macrofloral assemblages from weibei coalfield with reference to vegetational change through the late paleozoic ice age in the north china block abstract based on investigations of seven stratigraphic sections in the weibei coalfield a typical coal basin in the north china block the succession of late paleozoic plant macrofossil assemblages from the benxi or penchi in old spelling taiyuan shanxi lower shihhotse and upper shihhotse formations were redefined these zones are the paripteris spp linopteris spp conchophyllum richthofenii assemblage benxi fm neuropteris pseudovata lepidodendron posthumii assemblage taiyuan and lower shanxi fms emplectopteridium alatum emplectopteris triangularis cathaysiopteris whitei assemblage upper shanxi and lower shihhotse fms gigantonoclea lagrelii fascipteris hallei lobatannularia heianensis assemblage upper shihhotse fm as a result of this biostratigraphic reanalysis it has become clear that biostratigraphic boundaries do not exactly correlate to lithostratigraphic boundaries as has been thought the biostratigraphy of the terrestrial deposits in the north china block were correlated to the iugs global chronostratigraphy the more precise chronostratigraphic constraints that were obtained as a result of this study make it possible to more precisely correlate the vegetational successions to the concurrent waxing and waning of the late paleozoic ice sheets

carbon isotope behaviour in wood and cellulose during artificial aging abstract modern wood was subjected to an artificial decay process to investigate its behaviour with respect to the stable carbon isotope composition of wood and the corresponding cellulose four different woods were used namely oak quercus robur beech fagus sylvatica pine pinus sylvestris sequoia sequoiadendron giganteum and pure spruce cellulose the process of decay was simulated by heating samples in water at 180 c from minutes to months during the decay period the carbon content of wood increased to almost 70 while the cellulose content decreased gradually to zero the degradation proceeds according to a two stage process an initial very fast break down is followed by a rather slow degradation after a strong discrimination against 13 c during the initial phase the 13c 12c ratio increases again mostly up to its initial value the carbon isotope trend for cellulose shows a similar pattern though it is less pronounced maximum discrimination was 1 relative to the untreated wood 13c values of cellulose decreased by up to 0 3 the 13 c depletion is presumably a consequence of the preferential decomposition of cellulose as compared to lignin data on fossil trees are compared with the results obtained from this treatment of aging the 13 c decrease is in line with observations from these fossil woods but the ensuing 13 c enrichment is at most weakly to be seen

mooring observations of equatorial currents in the upper 1000 m of the western pacific ocean during 2014 time depth variations of the equatorial currents over the upper 1000 m depth in the western pacific ocean were directly measured by acoustic doppler current profiler moorings at 2 degrees n 140 degrees e and 4 7 degrees n 140 degrees e during january august 2014 intraseasonal variations of the equatorial currents with periods of 37 73 days were observed encompassing the north equatorial countercurrent necc northern branch of the south equatorial current sec equatorial undercurrent euc equatorial intermediate current eic north intermediate countercurrent nicc and north equatorial subsurface current nesc compared with previous studies based mainly on shipboard synoptic surveys the 8 month time series of velocity profiles provided direct evidence for the existence of nesc captured reversals of the eic in may and the nesc in june from westward to eastward direction and revealed larger vertical extensions of the sec and nesc and greater depths of the eic and nicc than previously thought according to a global analysis product of ocean surface current during january april 2014 the necc was located around its southernmost position and with its the weakest intensity over the past 20 years some of the anomalous characteristics of these flows may be related to the fickle el nino of 2014

paleogeography and paleoecology of the upper miocene zillingdorf lignite deposit austria abstract the zillingdorf deposit formed during the late miocene filling of lake pannon and contains austria s largest lignite reserves two lignite seams are present and developed within frequently flooded low lying mires in near shore environments high sulphur contents are due to the influence of the brackish water body of lake pannon during peat accumulation a transgression forced the nw se trending shoreline northeastwards differences in soluble organic matter som yield and hydrocarbon content of borehole samples and woody macrofossils are related to differences in the content and composition of free lipids of microbial origin and or hydrocarbons derived from the biogeochemical degradation of plant tissue variations of pristane phytane ratios are interpreted to reflect differences in the redox conditions of the mire peatification in an acidic and aerobic environment is further reflected by the predominance of aromatic over saturated hydrocarbons the presence of an intense complex mixture in the gc traces due to biodegradation processes high ratios for diasterenes relative to sterenes and high concentration ratios of hopanes to hop 17 21 ene of the respective samples gelification of plant tissue is governed by microbial activity as indicated by the positive relationship between gelification index and hopanoids concentration the composition of terpenoid biomarkers indicates the predominance of gymnosperms over angiosperms and increasing proportions of angiosperms in the peat forming vegetation with decreasing depth in the upper seam from the sesqui and diterpenoids present in the lignite and fossil wood remnants a predominant role of species of the coniferales families cupressaceae taxodiaceae are concluded the preservation of plant tissue is governed by the presence absence of decay resistant gymnosperms a general influence of the floral assemblage on the isotopic composition of organic carbon of the lignite 13c 27 2 to 24 6 is proposed decomposition of plant tissue and biogeochemical carbon cycling is assumed to further affect the 13c values of the lignite carbon isotope data of fossil wood remnants are consistent with their chemotaxonomical classification as gymnosperms 13c between 22 5 and 24 9 and angiosperms 13c between 25 5 and 26 6 respectively the 13c data of the extracted cellulose reveal clear differences between fossil wood from gymnosperms average 13c 20 3 and angiosperms mean 13c 22 9 the higher isotopic difference of about 3 5 between cellulose and fossil wood compared to that found in modern trees is explained by the smaller effect of 13c discrimination for cellulose when compared with wood during decomposition

thermal regime of the southwest japan subduction zone effects of age history of the subducting plate abstract during a mid miocene at about 15 ma tectonic reorganization an ocean spreading ridge perpendicular to the strike of the nankai trough subduction zone stopped spreading since that time there has been subduction of the cooling fossil spreading ridge in the present study we have developed a time dependent thermal subduction model for this region using the finite element method there are good seismological and geological constraints for the plate geometry and for the subduction history of the past 15 ma boundary conditions are specified so that the oceanic plate subducting at the nankai trough becomes cooler as it gets older the model results agree with the present heat flow trend that decreases landward and explain the paleothermal regime of high mid miocene temperatures inferred from land geological studies the tectonics of the region prior to 15 ma has some uncertainties assuming subduction of an active spreading ridge or an 80 ma old lithosphere prior to 15 ma give the same results for the present thermal regime of the seaward portion of the forearc but different results for the most landward region 250 km the thermal history of the forearc since 15 ma can be summarized as a rapid warming period as a consequence of ridge subduction followed by a cooling trend to the present as a result of the aging of the subducting plate the results illustrate the thermal consequences of one type of ridge subduction they also demonstrate that the thermal regime of a subduction zone depends critically on the age history of the subducting oceanic lithosphere especially if it is young as well as such parameters as the subducting plate dip angle and thickness of insulating sediments on the incoming oceanic crust this dependence is especially important when the thermal regime is used to constrain the seismogenic behaviour of the subduction thrust fault

thermal constraints on the seismogenic portion of the southwestern japan subduction thrust for coastal cities an important factor in earthquake hazard from subduction zone earthquakes is the landward extent of the seismogenic portion of the subduction thrust fault in this study we test the hypothesis that the maximum downdip extent is defined by a critical temperature we have developed a transient thermal model for the nankai subduction zone of southwest japan to allow comparison of the thermally estimated downdip extent of the seismogenic zone with that from 1 seismicity and tsunami data for two great subduction earthquakes 2 the coseismic faulting extent of these events estimated from geodetic deformation data and 3 the interseismic locked zone determined from interseismic geodetic data the nankai margin has extensive heat flow and heat production data to control thermal models and thus crustal temperatures it has earthquake tsunami and geodetic data that constrain the coseismic rupture portion of the subduction thrust fault for past great earthquakes and the portion of the thrust fault that is locked and storing interseismic elastic strain on the nankaido margin off shikoku island the thermal model indicates that a temperature of 350 c taken to be the limit for seismic initiation from laboratory and field data is reached on the subduction thrust fault 150 km from the trench a transition zone into which rupture may extend with decreasing offset taken to be 450 c extends an additional 45 km downdip the thermal model results are in excellent agreement with the maximum downdip extent of coseismic displacement for the 1946 nankaido ms 8 2 earthquake off shikoku island and with the downdip extent of the present locked zone in the region of the 1944 tonankai ms 8 2 earthquake to the northeast the subduction angle is much steeper and the thermal models indicate a narrower downdip seismogenic extent the seismogenic locked zone from earthquake and geodetic data is also narrower thus our analysis of the southwest japan margin indicates that all three constraints on the downdip extent of the seismogenic zone thermal coseismic and interseismic geodetic data are in general agreement the study also supports the hypothesis that the seismogenic portion of subduction thrust faults is limited primarily by temperature the thermal control implies that subduction thrust faults with shallow dip have wider seismogenic zones compared to those with steep dip the subducting plate age and thus heat flow and the thickness of the insulating sediments on the incoming plate are also very important to the thermal regime and thus to the seismogenic width the relation of the maximum seismic rupture area to the interseismic locked zone is particularly important for earthquake hazard estimation on subduction margins such as cascadia where there have been no great historical events

porosity corrections for smectite rich sediments impact on studies of compaction fluid generation and tectonic history porosity is a fundamental parameter that must be correctly determined in order to relate physical property hydrologic and chemical flux studies to natural systems traditional porosity determinations generated from physical property or seismic data can greatly overestimate the true porosity of sediments in which hydrated minerals such as smectite are abundant to produce a true porosity distribution such data must be corrected to account for the h 2 o residing in smectite interlayers which can make up to 25 of the total hydrated mineral mass such h 2 o is easily removed from the mineral by oven drying and or exposure to low humidities standard physical property measurements can be corrected provided the weight percent smectite in the sediment is known and the interlayer h 2 o content of the mineral can be estimated we illustrate the significant consequences of this correction by comparing profiles of reported and corrected porosities for smectite rich barbados abyssal plain and accretionary wedge sediments from ocean drilling program leg 110 sites 671 and 672

stable isotope geochemistry of coals humic kerogens and related natural gases isotope systematics are well defined for conventional sapropelic type i ii kerogens and their associated bacterial and thermogenic natural gas products these geochemical tools are used to estimate source type maturity and depositional environment and as a correlation technique in many cases the natural gas signatures in near surface samples and drill cuttings can be used to classify or predict a deeper lying source rock or reservoir corresponding interpretative schemes for coals type iii kerogens and their associated hydrocarbons are progressing quickly the shift in attention to humic sources is driven primarily by depletion of conventional oil and gas resources and the economic and societal requirements of coal and coal bed methane carbon hydrogen and nitrogen stable isotope variations can be large between different coals and humic kerogens these differences can often be recognized in their bulk 13corg dorg and 15norg values isotope signatures of coals can be diagnostic of several factors including deposit age type geographic location maturity and generation history however these characteristic isotopic variations are substantially better defined by the c h and n isotope ratios of the separate maceral groups such as vitrinite exinite and inertinite this new application of stable isotopes at the maceral and compound levels have great potential to improve the interpretative precision over conventional whole coal or bulk techniques hydrocarbon gases including coal gases derived from coals and humic kerogens can be distinguished from type i ii sources based on their molecular rations i e c1 c2 c3 and by comparing their stable isotope compositions especially 13cch4 and dch4 the 13cc2h6 can also be valuable but ethane is generally present in small amount 1 vol and requires

the effects of early diagenesis on the chemical and stable carbon isotopic composition of wood abstract studies of modern and ancient buried wood show that there is a linear correlation between carbohydrate content and the stable carbon isotope composition as carbohydrates are preferentially degraded during early diagenesis as the carbohydrate content decreases the 13 c value of the degraded wood decreases 1 to 2 per mil approaching the value of the residual lignin these results indicate that carbohydrate degradation products are lost and not incorporated into the aromatic structure as lignin is selectively preserved during early diagenesis of wood these results also indicate that attempts to quantify terrestrial inputs to modern sedimentary organic matter based on 13 c values should consider the possibility of a 1 to 2 per mil decrease in the 13 c value of degraded wood

late permian global coal hiatus linked to 13c depleted co2 flux into the atmosphere during the final consolidation of pangea at a time when all continents were finally arrayed in their pangea supercontinental configuration 250 50 ma earth9s stratigraphy records a global and very abrupt coal discontinuity from the tartarian stage of the late permian to the middle triassic reduced coal productivity and or preservation overlaps with a period of anomalous oceanic and atmospheric decrease in 13 c as recorded in marine carbonates and organic matter and terrestrial plant and animal fossils from the northern and southern hemispheres during the same short period the peripheral margin of the entire supercontinent pangea except for the southern shores of tethys was effectively under compressive stress this unique tectonic state caused deformation and uplift of coal bearing foreland basins and oxidation of pangea9s vast peat deposits the latter resulted in a rapid massive 13 c depleted co 2 flux into the atmosphere which in turn may have forced global warming

δ18o and δ13c of permian brachiopods a record of seawater evolution and continental glaciation abstract two hundred sixty four 18 o and 13 c values of permian articulate brachiopod shells were analyzed and 81 of these values were characterized as well preserved and biostratigraphically well defined these were then utilized for construction of baseline oxygen and carbon isotope curves for the permian interval in addition 21 13 c whole rock values are reported for the wordian and capitanian the early permian asselian to artinskian times are characterized by 2 5 decrease in oxygen isotope values from 0 7 to 3 3 v pdb this is attributed to a 4 7 c increase in temperature in the southern urals concomitant with the retreat of the permo carboniferous ice sheets and return of the 18 o depleted melt water into the oceans the late permian samples from iran jolfa at kuh e ali bashi and china meishan yield 18 o values and presumably temperatures similar to those that followed the termination of the large scale glaciation in the lower permian in between the upper kungurian to capitanian samples from the delaware basin guadalupe mountains are enriched in 18 o at 1 5 to 3 we have no definitive explanation for these data but tentatively suggest that the anomaly can potentially be a result of evaporative enrichment of seawater in 18 o due to intracratonic arid setting of the basin the 18 o enriched nature of the zechstein samples 1 2 to 2 5 on the other hand is in all probability a reflection of the high evaporation rates in the zechstein sea the permian interval is characterized by a relatively constant 13 c at about 4 the exceptions are again the brachiopods from the delaware basin guadalupe mountains which show 1 6 increase in the guadalupian to values of up to 5 9 in the wordian a tentative explanation as in the case of oxygen is based on the proposition that the semi enclosed delaware basin was likely stratified with sequestration of the 13 c depleted carbon to the deeper water layers and a complementary 13 c enrichment in the upper oxygenated layer the coeval open ocean water dic may have been similar to that of the remainder of the permian interval at 4 as indicated by whole rock carbonate samples from oman sicily and iran in the latest permian the trend mimics the well known 13 c drop at the permian triassic boundary

temperatures in zones of steady state underthrusting of young oceanic lithosphere abstract rapid conduction of heat through the top surface of young oceanic lithosphere can contribute at least some of the heat necessary for high temperature low pressure metamorphism of rock buried in subduction zones and perhaps for melting in such environments we show that the steady state temperature on a major underthrust fault underlain by a slab of downgoing lithosphere equals the quotient of the temperature that would exist due to the cooling of a slab below the wedge in the absence of advection of heat by the downgoing slab divided by a dimensionless divisor this divisor depends only on the speed and dip of subduction the depth of the fault the coefficient of thermal diffusivity and the ratio of coefficients of thermal conductivity in the downgoing slab and in the overlying wedge this result extends an earlier analysis that did not take into account either the cooling of lithosphere as it is subducted or different coefficients of thermal conductivity in the slab and overlying wedge for a wide range of geologically common parameters numerically calculated steady state temperature fields for two dimensional heat transfer differ by less than a few percent and by at most 10 from those given by this simple analytical approximation this approximation also concurs with numerical calculations of james et al 1 that show that temperatures as high as 400 c at a depth of only 10 km in a subduction zone would require the subducted lithosphere to be younger than roughly 1 ma if no other source of heat were available in addition the formalism presented here permits a simple assessment of the relative importance of the youth of the subducted lithosphere and dissipative heating in the enhancement of temperatures near the fault surface for example modest shear stresses of about 50 mpa on faults with high slip rates of 100 mm yr or more at depths as small as 10 km can contribute as much as 200 c to temperatures on the fault making temperatures of 400 c at 10 km possible even when lithosphere as old as 20 30 ma is subducted

geochemistry of environmentally sensitive trace elements in permian coals from the huainan coalfield anhui china abstract to study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the permian period from the huainan coalfield anhui province china borehole samples of 336 coals two partings and four roof and floor mudstones were collected from mineable coal seams major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry icp oes inductively coupled plasma mass spectrometry icp ms and hydride generation atomic absorption spectrometry haas the depositional environment abundances distribution and modes of occurrence of trace elements were investigated results show that clay and carbonate minerals are the principal inorganic constituents in the coals a lower deltaic plain where fluvial channel systems developed successively was the likely depositional environment of the permian coals in the huainan coalfield all major elements have wider variation ranges than those of chinese coals except for mg and fe the contents of cr co ni and se are higher than their averages for chinese coals and world coals vertical variations of trace elements in different formations are not significant except for b and ba certain roof and partings are distinctly higher in trace elements than underlying coal bench samples the modes of occurrence of trace elements vary in different coal seams as a result of different coal forming environments vanadium cr and th are associated with aluminosilicate minerals ba with carbonate minerals and cu zn as se and pb mainly with sulfide minerals

three dimensional seismic structure beneath southwest japan the subducting philippine sea plate abstract a three dimensional seismic structure beneath southwest japan has been investigated in detail by applying an inversion method this analysis clearly reveals the present and possibly the past subduction of the philippine sea plate beneath southwest japan beneath the izu peninsula the philippine sea plate does not appear to subduct but collides against the continental asian plate here and its thickness appears thinnest at most about 30 km from the tokai to the shikoku regions the high velocity zone corresponds well to the zone of subcrustal earthquakes down to a depth of about 60 70 km indicating that the subduction of the present philippine sea plate does not reach below this depth here however a small high velocity portion appears at depths between 100 km and 150 km beneath a part of the kinki region and probably extends to the chugoku region where no corresponding seismic activities exist these high velocities might be an indication of the remnants of the past subduction of the philippine sea plate in the kyushu region the high velocity zone continues down to a depth of about 150 km or even to 200 km in the southern part corresponding to a steeply inclined seismic zone the philippine sea plate in this region appears to be thicker than in regions east of the kyushu palau ridge it was also found that there exist narrow low velocity zones intervening within the philippine sea plate where two aseismic ridges the kyushu palau and shichito iwojima ridges extend northwards and the nankai trough shows warping these low velocity zones give support to the buoyant subduction hypothesis it also appears that lateral heterogeneities existing within and around the subducting plate are closely related to the mode of rupture of large earthquakes occurring around there

america eurasia plate boundary in eastern asia and the opening of marginal basins abstract the opening of the arctic ocean during the past 55 ma resulted in relative rotation of america with respect to eurasia about a pole located in eastern siberia near the plate boundary the extensional plate boundary enters deep inside the eurasian continent up to the rotation pole on the opposite side of the pole on the pacific side of the plate boundary compressive tectonics are recorded along sakhalin and hokkaido from the oligocene to middle miocene the relative movement was accommodated by strike slip motion along sakhalin and hokkaido although the rotation pole was not located at a significatively different position from now in this paper we explain this by independent motion of the southernmost tip of the american plate towards the pacific margin which behaves as a free boundary this oceanward motion resulted in an extension of the american plate giving rise to the wedge structure of the okhotsk sea the japan sea opened as a pull apart basin along the strike slip boundary finally the increasing extension in the okhotsk sea led to the opening of the oceanic kuril basin

13c 12c ratio double cyclicity in a miocene browncoal isotopic signals and orbital forcing a detailed stable carbon isotopic profile of a late miocene browncoal seam from the lower rhine embayment germany reveals two clear separate cycles of different frequency this is the first instance of this type of isotopic signature being recognized within coals the ratio of the two frequencies suggests this isotopic signal possibly resulted from climatic or vegetational responses to orbital forcing the cyclicity has been enhanced by the application of conventional filtering methods on the data set an analysis of the seam s palynology indicates a correlation between heavier isotopic compositions and the presence of sequoiapollenites polyformosus whose parent plant is believed to have favoured moist climates and higher groundwater tables

petrographic characteristics and carbon isotopic composition of permian coal implications on depositional environment of sattupalli coalfield godavari valley india abstract the present paper entails a study carried out on selected samples of coal and carbonaceous shales of permian age from the sattupalli open cast coal mine of godavari valley andhra pradesh to know their petrographic and chemical characteristics based on these characteristics the depositional environment has also been discussed the study reveals that these coals are sub bituminous in rank and are chemically characterized by low to medium moisture 4 3 to 8 6 wt and volatile matter 24 5 to 32 6 wt while the ash yield varies between 16 4 and 35 3 wt petrographically these coals are rich in inertinite liptinites occur in very small concentration collotelinite collodetrinite and vitrodetrinite are the main vitrinite macerals whereas fusinite inertodetrinite and semi fusinite constitute the major proportion of inertinites mean 13c value measured for coal is 22 58 0 20 and for carbonaceous shale it is 23 64 0 57 while in the organic matter of barakar sandstones the 13c is 25 2 2 1 dry periods are reflected by the abundance of inertinite in some samples while more anoxic conditions are indicated by high concentration of vitrinite in some samples seam ii of sattupalli coalfield initially formed in dry condition and gradually flooding took place due to rise in the water table during the formation of the upper part of the seam again a relatively dry phase prevailed moreover a positive correlation of 13corg with toc and a negative one with tic indicate that 13corg is being modified by 13cdic

direct measurements of upper ocean currents and water properties across the tropical pacific during the 1990s abstract meridional sections of upper ocean zonal currents potential temperature and salinity are estimated at ten longitudes from 143 e to 95 w using conductivity temperature depth and acoustic doppler current profiler data from 172 synoptic sections taken in the tropical pacific between 138 e and 86 w mostly in the 1990s data reduction is carried out in a potential isopycnal and mixed layer framework to preserve a sharp pycnocline a mixed layer water property extrema and velocity extrema mean zonal currents potential temperatures and salinities are produced at each longitude the seasonal cycles of these fields are also estimated as well as a simple el nino southern oscillation enso cycle zonal sections along the equator are also presented properties of the near equatorial zonal currents including transports temperatures and salinities are estimated separately from the synoptic sections the seasonal cycles of these quantities and their correlations with the southern oscillation index are investigated the work is distinguished from most existing literature in that direct estimates of zonal velocity are combined with contemporaneous temperature and salinity data allowing trans pacific estimates of near equatorial current transports and properties including those of the northern branch of the south equatorial current the new guinea coastal undercurrent and the equatorial undercurrent

fluid generation and distribution in the highest sediment input accretionary margin the makran fluids in subduction zones can influence seismogenic behaviour and prism morphology the eastern makran subduction zone offshore pakistan has a very thick incoming sediment section of up to 7 5 km providing a large potential fluid source to the accretionary prism a hydrate related bottom simulating reflector bsr zones of high amplitude reflectivity seafloor seep sites and reflective thrust faults are present across the accretionary prism indicating the presence of fluids and suggesting active fluid migration high amplitude free gas zones and seep sites are primarily associated with anticlinal hinge traps and fluids here appear to be sourced from shallow biogenic sources and migrate to the seafloor along minor normal faults there are no observed seep sites associated with the surface expression of the wedge thrust faults potentially due to burial of the surface trace by failure of the steep thrust ridge slopes thrust fault reflectivity is restricted to the upper 3 km of sediment and the deeper decollement is non reflective we interpret that fluids and overpressure are not common in the deeper stratigraphic section thermal modelling of sediments at the deformation front suggests that the deeper sediment section is relatively dewatered and not currently contributing to fluid expulsion in the makran accretionary prism

on the role of anomalous ocean surface temperatures for promoting the record madden julian oscillation in march 2015 a madden julian oscillation mjo event dramatically amplified at the beginning of march 2015 as the convective phase traversed an unusually warm central pacific ocean this record amplification also resulted in record amplitude of the mjo based on index measurements since 1974 we explore the possible role of the anomalously high ocean surface temperatures in the equatorial central pacific for promoting the extraordinary amplification of this mjo event forecast sensitivity experiments with the predictive ocean atmosphere model for australia show that the enhanced growth of the mjo resulted from amplification of the convective anomaly as it encountered the unusually warm central pacific our results indicate that anomalous sea surface temperature sst at the onset of el nino 2015 promoted the intensification of the mjo we suggest a two way interaction whereby initial sst anomalies promoted enhanced mjo activity which then possibly led to enhanced el nino development

structure of the nankai trough accretionary zone from multichannel seismic reflection data new multichannel seismic reflection data collected over the nankai trough image the accretionary complex in two areas the international program of ocean drilling leg 87 transect area western area and the region of upcoming ocean drilling program leg 131 eastern area the incoming shikoku basin sedimentary section consists of hemipelagic clays and thin terrigenous turbidites the basin section is overlain by a trench wedge that is 12 16 km wide and 350 750 m thick at the thrust front accretionary deformation begins in a protothrust zone that is characterized by thickening and seaward tilting of the trench wedge the zone in the western area is 4 5 km wide and is characterized by kink folds the zone in the eastern area is only 2 5 km wide and does not exhibit such folds the frontal thrusts in each area are imaged as fault plane reflections and ramp upward from within the basin hemipelagic section the overthrusting sediments form fault bend folds over these ramps thrust spacing at the toe of the slope is 1 5 2 5 km the second thrust cuts up from an inferred decollement within the shikoku basin sedimentary section in the eastern area a reflection marking the top of the basin pelagic sediment section changes from normal to reversed polarity about 6 3 km seaward of the thrust front and underlies the entire protothrust zone this reflector continues with reversed polarity under the accretionary complex and is at the level of the basal decollement the underlying basin pelagic section is apparently thrust undisturbed beneath the accretionary prism the reversal of polarity indicates a change in reflection coefficient that is due to a combination of decreasing seismic velocity and density across the interface this decrease in velocity and density may indicate that the decollement is a zone of high porosity due to fluid expulsion from deeper within the accretionary prism the reflections from the first and second thrusts are also reversed polarity possibly indicating that they also are pathways of fluid expulsion the critical wedge taper of the western area is greater than that of the eastern area an observation that is consistent with the existence of an overpressured decollement in the eastern area

combining 2d basin and structural modelling to constrain heat transport along the muroto transect nankai trough japan abstract the nankai trough located southeast of shikoku island japan exhibits a zone of exceptionally high heat flow in the central part of the nankai trough the fossil spreading centre of the shikoku basin is subducted beneath the southwest japan arc we have modelled the temperature and maturation history along the muroto transect reaching from the tip of the thrust zone out into nearly undeformed quaternary and tertiary sediments seawards of nankai trough we used two balanced cross sections defining the sections before and after overthrusting as input for 2d basin modelling we can show that rapid burial and overthrusting during the quaternary in combination with a heat flow history following the cooling curve of a 15 ma old oceanic plate is not sufficient to explain the measured maturity of organic material in the sediments several heat flow scenarios derived from theoretical concepts yamano m kinoshita m goto s matsubayashi o 2003 extremely high heat flow anomaly in the middle part of the nankai trough physics and chemistry of the earth parts a b c 28 487 497 and previous modelling approaches e g brown k m saffer d m bekins b a 2001 smectite diagenesis pore water freshening and fluid flow at the toe of the nankai wedge earth and planetary science letters 194 97 109 spinelli g a underwood m b 2005 modeling thermal history of subducting crust in nankai trough constraints from in situ sediment temperature and diagenetic reaction progress geophysical research letters 32 l09301 doi 10 1029 2005gl022793 steurer j underwood m b 2003 clay mineralogy of mudstones from the nankai trough reference sites 1173 and 1177 and frontal accretionary prism site 1174 in h mikada et al eds pp 1 37 available from were tested the best match between observed maturity levels temperature and heat flow measurements is reached for a heat flow history which initially assumes the cooling of a 15 ma old oceanic lithosphere but is reheated to 170 180 mw m 2 during the phase of rapid burial in the quaternary this can be achieved either by assuming the onset of hydrothermal circulation in the cooling crust or by reheating caused by off axis volcanism at about 6 ma yamano m kinoshita m goto s matsubayashi o 2003 extremely high heat flow anomaly in the middle part of the nankai trough physics and chemistry of the earth parts a b c 28 487 497

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

deep ocean impact of a madden julian oscillation observed by argo floats using the new argo array of profiling floats that gives unprecedented space time coverage of the upper 2000 meters of the global ocean we present definitive evidence of a deep tropical ocean component of the madden julian oscillation mjo the surface wind stress anomalies associated with the mjo force eastward propagating oceanic equatorial kelvin waves that extend downward to 1500 meters the amplitude of the deep ocean anomalies is up to six times the amplitude of the observed annual cycle this deep ocean sink of energy input from the wind is potentially important for understanding phenomena such as el nino southern oscillation and for interpreting deep ocean measurements made from ships

intraseasonal variability of the surface zonal currents in the western tropical pacific ocean characteristics and mechanisms abstractthe surface circulation of the tropical pacific ocean is characterized by alternating zonal currents such as the north equatorial current nec north equatorial countercurrent necc south equatorial current sec and south equatorial countercurrent secc in situ measurements of subsurface moorings and satellite observations reveal pronounced intraseasonal variability isv 20 90 days of these zonal currents in the western tropical pacific ocean wtpo the amplitude of isv is the largest within the equatorial band exceeding 20 cm s 1 and decreases to 10 cm s 1 in the necc band and further to 4 8 cm s 1 in the nec and secc the isv power generally increases from high frequencies to low frequencies and exhibits a peak at 50 60 days in the necc sec and secc these variations are faithfully reproduced by an ocean general circulation model ogcm forced by satellite winds and parallel model experiments are performed to gain insights into the underlying mechanisms it is found that large sca

the interplate coupling and stress accumulation process of large earthquakes along the nankai trough southwest japan derived from geodetic and seismic data abstract the interplate coupling and stress accumulation process associated with the subduction of the philippine sea plate beneath the eurasian plate along the nankai trough where large earthquakes have occurred periodically have been investigated in detail taking into account the three dimensional complicated structure of the philippine sea plate and its motion relative to the eurasian plate for this purpose we mainly used extensive geodetic data in southwest japan such as levelling tide gauge and trilateration which presumably are effective means of revealing coupling properties and applied a three dimensional finite element method here two seismic periods associated with the 1944 tonankai and 1946 nankaido earthquakes were considered interseismic and pre seismic stages comparing the coupled regions obtained for the two cases a possible explanation of its temporal change was proposed it might gradually spread from a shallower to deeper portion with transition from the interseismic to pre seismic stage a comparison of the coupling properties between southwest japan and northeast japan reveals the following properties in southwest japan the coupling is generally strong and its region is limited in a relatively shallow portion the pre seismic coupled regions coincide with the co seismic and post seismic fault zone suggesting that the accumulated stress is released at the time of a large earthquake in northeast japan on the other hand the coupling is weak and its extent appears to reach a depth of about 100 km and the co seismic and post seismic regions are limited to the upper half of the coupled region the weakly coupled region in southwest japan seems to correspond well to the region with high seismic activity a high dip angle subducting slab and the possible existence of seamounts in contrast to the strongly coupled region correlated with low seismicity low dip angle subduction and no seamounts on the western coupled region off shikoku an anomalously strongly coupled region corresponding to a convergence rate of 7 8 cm year 1 was identified this may be caused by geomorphological properties such as the low dip angle of the subducting plate and smooth plate boundary resulting in a large amount of stress concentration there the stress field associated with the interplate coupling was also calculated there is fair agreement between the observations and calculations near the plate boundary beneath the southern kii peninsula and shikoku although the effects of the interplate coupling may have some influence on strike slip faulting with the n s compressive axes beneath shikoku other earthquake generating stress such as a two layered double buckling would be dominant there

depositional environment of the late miocene hausruck lignite alpine foreland basin insights from petrography organic geochemistry and stable carbon isotopes abstract lignites and fossil wood from two boreholes in the late miocene hausruck district alpine foreland basin austria were investigated with respect to organic carbon and total sulfur contents ash yields maceral composition organic geochemistry and stable carbon isotope ratios the lignites from the two sampled profiles differ in sulfur contents and petrography based facies indicators gelification index gi tissue preservation index tpi the results point to drier and more acidic conditions in the part of the mire sampled at drill site lukasberg whereas the lignites from kalletsberg formed under near neutral conditions due to a raised ground water table the different depositional environments are supported by the paleogeographic positions of the boreholes borehole lukasberg is located within a paleo valley whereas borehole kalletsberg is located at the deeper part of a basin situated south and southwest of the hausruck area environmental changes with time within the mire are confirmed by the molecular composition of the soluble organic matter som differences in pristane phytane ratio isomerisation of hopanes at position 17 concentrations of hopanes and in the ratio of hopanes to hop 17 21 enes are related to the extent of gelification of plant tissue sulfur content and ph values caused by differences in ground water table the variable contents of individual terpenoid hydrocarbons derived from land plants indicate that angiosperms and conifers contribute to peat formation in the hausruck district in variable proportions overall angiosperm biomarkers slightly predominate the tissue preservation index tpi within the kalletsberg profile is probably governed by the proportion of decay resistant conifers as indicated by the correlation between tpi and biomarker composition of the coals correlations between 13 c values of the lignites between 24 9 and 27 4 and their non hopanoid terpenoid composition indicate the major influence of changes in peat forming vegetation on the carbon isotopic composition of the coals in the hausruck district carbon isotope data of macrofossils are consistent with their taxonomical classification as conifers 13 c between 22 7 and 25 1 and angiosperms 13 c between 25 5 and 26 6 respectively the 13 c data of the extracted cellulose reveal clear differences between fossil wood from gymnosperms average 13 c 21 0 and angiosperms mean 13 c 23 4

temperatures heat flux and frictional stress near major thrust faults we examine the two dimensional advective and conductive transport of heat in a region of thrust faulting both simple theoretical considerations and numerical experiments show that the steady state temperatures near the fault are reduced by a divisor s 1 b z vsin below what they would be with the same heat sources but in the absence of advection in this expression z is the depth to the fault v is the slip rate is the component of the dip of the fault in the direction of underthrusting is thermal diffusivity and b is a dimensionless factor that is essentially equal to one for most forms of heating initial changes in temperatures near the fault are given by t z t t z 0 12vsin t z 0 z these simple formulae are successful because of the neglible influence of lateral conduction of heat at least for slip rates of a few mm yr or more two time constants govern the transition from the initial change in temperature to steady state t1 u v where u is the distance along the fault in the direction of underthrusting from the surface to the depth in question and t2 z 2 2 where z is the depth to the fault when elapsed times exceed the sum of these two time constants temperatures differ from their steady state values by only about 10 percent the numerical experiments indicate that the simple formulae are sufficiently accurate that sophisticiated numerical modeling of temperatures in specific regions is unwarranted putain an application of these simple formulae to measurements of conductive heat flow at island arcs implies that shear stresses at island arcs approach 100 mpa and are greater than 30 mpa calculations of temperatures appropriate for the himalaya suggest that shear stresses of 100 mpa on the main central thrust probably are required to account for the tertiary granites of the region if melting took place after slip began on the thrust similarly the cut off in seismicity at a depth of about 15 km in the himalaya if due to temperatures exceeding 350 to 450 c implies a deviatoric stress close to 100 mpa

semiannually alternating exchange of intermediate waters east of the philippines intermediate water exchange in the northwest tropical pacific is explored with the temperature salinity and current measurements of a mooring system deployed at 8 degrees n 127 05 degrees e during 2010 2014 for the first time prominent semiannual variability sav with the maximum power at similar to 187days of subthermocline meridional flow along the mindanao coast is revealed a significant correlation between meridional flow and salinity is found at intermediate depths this provides direct evidence for the alternating transports of south pacific and north pacific intermediate waters by northward and southward undercurrents respectively further analysis with an eddy resolving ocean general circulation model demonstrates that the sav is generated locally near the western boundary manifesting as large scale subthermocline recirculation and leading to alternating northward and southward flows near the mindanao coast which plays an efficient role in the intermediate water exchange of the northwest tropical pacific mechanisms underlying the observed sav are discussed

the effects of sedimentation and compaction on oceanic heat flow summary the estimation of environmental effects forms an important part of the interpretation of oceanic heat flow measurements in particular the perturbations associated with sedimentation and surface temperature changes must be taken into account analytical solutions can be obtained only for individual simplified versions of these problems whereas any real example is complicated by the process of sediment compaction which changes the bulk thermal properties with depth a physical model is developed which uses sediment porosity trends to predict the thermal parameters and material advection rates for an evolving sediment basement system these values are then used in a numerical solution to the heat flow equation to give estimates of the perturbed surface heat flux through time in addition to variations in sedimentation rate sediment type radioactive heat production and surface temperature changes are considered heat flow corrections may vary by up to a factor of 2 according to sediment type while radioactive heat production can offset the effects of sedimentation by as much as 40 per cent the results also indicate that alterations determined from simple analytical models tend to over estimate the true perturbation to the flux

estimation of oceanic hydrothermal heat flux from heat flow and depths of midocean ridge seismicity and magma chambers the difference between the heat flow predicted by thermal models of the lithosphere and that measured at the seafloor can be used to estimate the cooling by hydrothermal circulation however this approach may yield an overestimate because measurements in thinly sedimented young crust are typically made at topographic lows where hydrothermal circulation may systematically lower heat flow to circumvent this bias we estimate the cooling using the depths of midocean ridge earthquakes and magma chambers in addition to heat flow data the results indicate deeper hydrothermal circulation at slow spreading ridges and higher near axial hydrothermal heat loss at fast spreading ridges the predicted global hydrothermal heat flux is 80 of that for models constrained only by heat flow

mesoscale eddies in the south china sea mean properties spatiotemporal variability and impact on thermohaline structure we investigated mean properties and the spatiotemporal variability of eddies in the south china sea scs by analyzing more than 7000 eddies corresponding to 827 eddy tracks identified using the winding angle method and 17 years of satellite altimetry data eddies are mainly generated in a northeast southwest direction and southwest of luzon strait there is no significant difference between the numbers of two types of eddies anticyclonic and cyclonic in most regions the mean radius and lifetime of eddies are 132 km and 8 8 weeks respectively both depending on where the eddies are formed anticyclonic and cyclonic eddies tend to deform during their lifetimes in different ways furthermore eddy propagation and evolution characteristics are examined in the northern scs eddies mainly propagate southwestward along the continental slope with velocities of 5 0 9 0 cm s 1 while in the central scs eddies tend to move with slight divergence but still in a quasi westward direction with velocities of 2 0 6 4 cm s 1 eddy propagation in the western basin to the east of vietnam is quite random with no uniform propagate direction investigation of 38 long lived eddies shows that eddies have a swift growing phase during the first 12 weeks and then a slow decaying phase that affects the eddy radii and eddy energy densities nevertheless vorticity has less variability in addition the effect of eddies on the thermocline and halocline is analyzed using 763 argo temperature profile data cyclonic eddies drive the thermocline shallower and thinner and significantly strengthen the thermocline intensity whereas anticyclonic eddies cause the thermocline to deepen and thicken and weaken the thermocline intensity to a certain degree the halocline impacted by cyclonic eddies is also shallower and thinner than that impacted by anticyclonic eddies finally eddy temporal variations are examined at seasonal and interannual scales eddy activity is sensitive to the wind stress curl and in the northern scs it is also related with the strength of the background flows

environmental history of the german lower rhine embayment during the middle miocene as reflected by carbon isotopes in brown coal stable carbon isotope investigations have been carried out on miocene brown coal from the garzweiler seam of the german lower rhine embayment material studied included fossil wood from seven different taxa and brown coal matrix isotope results from macrofossil analysis show variations of more than 6 within individual samples and reveal a general isotopic difference between angiosperm and gymnosperm wood specimens according to mean carbon isotope values found for gymnosperms angiosperms and brown coal matrix 23 3 26 0 and 25 8 the peat forming vegetation of the garzweiler seam was dominated by angiosperm taxa results from brown coal matrix establish a continuous high resolution depth profile of carbon isotope variations during the late middle miocene they show a significant and characteristic isotope pattern with distinct medium and short term cycles high frequency variations in the two main units of garzweiler seam locally split into three units the medium term 13c variations are most likely caused by varying proportions of gymnosperms within the peat forming vegetation while high frequency oscillations seem to be a direct signal of environmental changes a long term decline of carbon isotope values observed within the complete garzweiler seam from base to top is presumably due to a cooling trend in the miocene

contrasting intraseasonal variations of the equatorial pacific ocean between the 1997 1998 and 2015 2016 el nino events oceanic intraseasonal variability isv plays a vital role in the initiation and development of el nino events mooring observations reveal contrasting characteristics of upper ocean zonal current isv during different el nino events compared to the 1997 1998 event isv of the 2015 2016 event was significantly weaker by around 30 50 over the equatorial pacific basin and the variability maximum was shifted to the east similar to 160 degrees e these differences can be largely explained by wind forcing features isv of surface winds in 2015 is overall weaker than in 1997 intraseasonal westerly wind bursts in 1997 occurred near the western boundary and originated from the indian ocean whereas in 2015 perturbations were mainly propagated from the northeast pacific and achieved the peak power at similar to 160 degrees e of the equator these changes are likely associated with the decadal warming of the northeast subtropical pacific and weakening of the indian ocean intraseasonal oscillation plain language summary sea surface warmings of strong el nino events are usually triggered by intraseasonal oscillations prior to the events particularly intraseasonal eastward ocean currents generated by westerly wind bursts carry the warm water of the western pacific warm pool to the central pacific and contribute to the surface warming in this paper we compare the intraseasonal zonal current variations during two strong el nino events namely the 1997 1998 and 2015 2016 events although the two el nino events were of comparable strengths intraseasonal variations in 1997 were stronger than those in 2015 by 3050 these differences can be largely explained by the contrasting features of wind forcing intraseasonal oscillations were originated from the indian ocean in 1997 whereas those in 2015 were mainly from the northeast subtropical pacific the varying origin is likely associated with the warming of the northeast subtropical pacific and weakened indian ocean intraseasonal oscillation during recent years

living microbial ecosystems within the active zone of catagenesis implications for feeding the deep biosphere earth s largest reactive carbon pool marine sedimentary organic matter becomes increasingly recalcitrant during burial making it almost inaccessible as a substrate for microorganisms and thereby limiting metabolic activity in the deep biosphere because elevated temperature acting over geological time leads to the massive thermal breakdown of the organic matter into volatiles including petroleum the question arises whether microorganisms can directly utilize these maturation products as a substrate while migrated thermogenic fluids are known to sustain microbial consortia in shallow sediments an in situ coupling of abiotic generation and microbial utilization has not been demonstrated here we show using a combination of basin modelling kinetic modelling geomicrobiology and biogeochemistry that microorganisms inhabit the active generation zone in the nankai trough offshore japan three sites from odp leg 190 have been evaluated namely 1173 1174 and 1177 drilled in nearly undeformed quaternary and tertiary sedimentary sequences seaward of the nankai trough itself paleotemperatures were reconstructed based on subsidence profiles compaction modelling present day heat flow downhole temperature measurements and organic maturity parameters today s heat flow distribution can be considered mainly conductive and is extremely high in places reaching 180 mw m2 the kinetic parameters describing total hydrocarbon generation determined by laboratory pyrolysis experiments were utilized by the model in order to predict the timing of generation in time and space the model predicts that the onset of present day generation lies between 300 and 500mbelow sea floor 5100 5300mbelow mean sea level depending on well location in the case of site 1174 5 10 conversion has taken place by a present day temperature of ca 85 c predictions were largely validated by on site hydrocarbon gas measurements viable organisms in the same depth range have been proven using 14c radiolabelled substrates for methanogenesis bacterial cell counts and intact phospholipids altogether these results point to an overlap of abiotic thermal degradation reactions going on in the same part of the sedimentary column as where a deep biosphere exists the organic matter preserved in nankai trough sediments is of the type that generates putative feedstocks for microbial activity namely oxygenated compounds and hydrocarbons furthermore the rates of thermal degradation calculated from the kinetic model closely resemble ratesof respiration and electron donor consumption independently measured in other deep biosphere environments we deduce that abiotically driven degradation reactions have provided substrates for microbial activity in deep sediments at this convergent continental margin

interaction between the chile ridge and chile trench geophysical and geothermal evidence geophysical and geothermal data are examined from the three southernmost sections of the chile ridge starting at 44 s and continuing south to the triple junction of the nazca antarctic and south america plates at 47 s these sections represent three progressively younger stages in a ridge trench collision event corresponding to 3 m y before the collision 1 m y before the collision and culminating in an ongoing collision at the triple junction magnetic and bathymetric data across the chile rise indicate that there is little change in the configuration of the spreading center as the ridge approaches and then collides with the trench in the collision zone a normal looking rift valley can be traced for 40 km before it disappears beneath the toe of the landward trench slope there is no evidence for the complex pattern of ridge jumps and spreading center rotations that occurred when the pacific farallon spreading center collided with north america in contrast the overriding plate is greatly affected by the ridge collision the landward trench slope steepens and narrows as the collision zone is approached at the southern end of the collision zone a ridge associated with the taitao fracture zone is colliding with the trench and may be in the process of being obducted onto the landward trench slope geothermal measurements were made along three transects of the margin corresponding to the time 3 m y before the collision during the collision and 6 m y after the collision the heat flow measurements in the collision zone document a large pulse of heat associated with the subduction of the ridge values as high as 345 mw m2 were recorded on the lower trench slope a prominent bottom simulating reflector bsr observed over a wide area of the landward trench slope north of the triple junction and more locally south of the triple junction is used to expand the grid of heat flow observations excellent agreement is found between measured heat flow and estimates of heat flow based on the depth to the bsr the heat flow measurements compare favorably with a theoretical model assuming conductive heat flow we estimate that the accretionary prism has been substantially removed in the collision zone and conclude that the landward trench slope is undergoing an episode of rapid tectonic erosion periodic ridge collisions in the past may account for the apparent truncation of the andean forearc region

an exceptional anticyclonic eddy in the south china sea in 2010 the highest sea level near the xisha islands in recent 20 years occurred during august 2010 satellite altimeter data indicated that the extreme event was largely due to an anticyclonic eddy whose amplitude exceeded 20 cm and size exceeded 400 km on 11 august 2010 cruise observations showed the eddy raised the center temperature by 7 7 degrees c at 75 m and vertically extended to 500 m eddy tracking showed it had a life span of more than 8 months and propagated far from the south of xisha islands such strong and long lasting eddy that moved northward for such a long distance was observed for the first time in the south china sea scs observational data from ctd xbt and the reconstructed three dimensional temperature and salinity were used to explore the eddy s features and vertical structure our analyses show the 2010 summer monsoon and current in the western boundary of the scs were largely altered after the 09 10 el nino event from may onward the wind blew northward and strengthened over the northwestern scs such wind drove a strong northward current along the western boundary which carried the eddy northward by advection from may to july energy budget showed during the eddy northward propagation the boundary current passed energy to the eddy which led to the continuing growth of the eddy in both strength and size