evidence for multiple sources for inorganic components in the tucheng coal deposit western guizhou china and the lack of critical elements abstract terrigenous materials from sediment source regions are important controls on the types and concentrations of inorganic components in coal the kangdian upland dominated by the emeishan basalts is the dominant terrigenous supplier for most of the late permian coals as well as for their associated host rocks roof and floor strata in southwestern china the high volatile bituminous coals nos 3 and 6 coals are the two major minable coal seams in the tucheng coal deposit in southwestern china unlike most late permian coals in this region that are characterized by elevated concentrations of the element assemblage sc v cr co ni cu zn se these two coals are not enriched in this assemblage although se is slightly concentrated the mineralogical e g relatively abundant quartz and mixed layer illite smectite and elemental distribution patterns e g spider diagrams of rare earth elements discrimination diagrams of al2o3 tio2 and zr tio2 nb y and elemental assemblages indicate that the inorganic components in the two coal seams were mainly derived from unidentified volcanic arc and or distal orogens while the clastic components in the roof and floor strata of the two coal seams were mainly supplied by the high ti emeishan basalts the two partings in the two coal seams identified as tonsteins were probably derived from the final rejuvenated activity of the emeishan plume critical elements in the two coals and associated non coal horizons partings roof and floor strata are economically unpromising indicating that prospecting for late permian coal hosted critical metal ore deposits in the vicinity of the emeishan plume in southwestern china should not be focused on coals with inorganic components derived mostly from distal volcanic arcs and orogens and high ti emeishan basalts and a minor contribution of volcanic ashes resulting from the final rejuvenated activity of the emeishan plume

marine oxygenation lithistid sponges and the early history of paleozoic skeletal reefs abstract microbial carbonates were major components of early paleozoic reefs until coral stromatoporoid bryozoan reefs appeared in the mid ordovician microbial reefs were augmented by archaeocyath sponges for 15 myr in the early cambrian by lithistid sponges for the remaining 25 myr of the cambrian and then by lithistid calathiid and pulchrilaminid sponges for the first 25 myr of the ordovician the factors responsible for mid late cambrian microbial lithistid sponge reef dominance remain unclear although oxygen increase appears to have significantly contributed to the early cambrian explosion of marine animal life it was followed by a prolonged period dominated by greenhouse conditions as sea level rose and co2 increased the mid late cambrian was unusually warm and these elevated temperatures can be expected to have lowered oxygen solubility and to have promoted widespread thermal stratification resulting in marine dysoxia and hypoxia greenhouse conditions would also have stimulated carbonate platform development locally further limiting shallow water circulation low marine oxygenation has been linked to episodic extinctions of phytoplankton trilobites and other metazoans during the mid late cambrian we propose that this tendency to dysoxia hypoxia in shallow marine environments also limited many metazoan reef builders in contrast during the mid late cambrian the ability of lithistid sponges to withstand low oxygen levels allowed them to create a benthic association with microbial carbonates that dominated global reefs these conditions ameliorated during the ordovician as temperature decline promoted ocean ventilation the prolonged time gap occupied by low diversity reefs between the cambrian explosion and the great ordovician biodiversification event reflects elevated temperatures and reduced marine oxygenation that limited metazoan diversification in shallow marine environments

characterisation of ottnangian middle burdigalian palaeoenvironments in the north alpine foreland basin using benthic foraminifera a review of the upper marine molasse of southern germany abstract considerable facies changes and varying foraminiferal assemblages have been described from the lower miocene sediments of the upper marine molasse in the north alpine foreland basin of southern germany and have resulted in the distinction of a western molasse and eastern molasse however the causes and processes leading to these local differences have largely remained unexplored to date the aim of this study is to explore possible explanations in order to better understand the palaeogeographic stratigraphic and environmental setting the study focuses on the ottnangian middle burdigalian segment of the upper marine molasse in southern germany and includes a review of previously published data together with new data from the borehole stockhausen which is located between the areas of the eastern and western molasse methods include quantitative analysis of benthic foraminiferal assemblages qualitative studies of planktonic foraminifera and calcareous nannoplankton as well as palaeoenvironmental considerations based on the actualistic approach the results of these studies demonstrate that the lower and middle ottnangian upper marine molasse include a single transgressive regressive sedimentary cycle with gradual changes of foraminiferal assemblages in the eastern molasse on the other hand two sedimentation cycles are recognizable in the western molasse and in the borehole stockhausen where the lower and middle ottnangian sediments are separated from one another by an unconformity and display an abrupt change in lithofacies and foraminiferal content the benthic foraminiferal assemblages from the area of the western molasse are indicative of a rather shallow sea but indicative of a much deeper facies in the basin area of the eastern molasse it can therefore be concluded that the shallow sea to the west was more sensitive to minor changes in sea level than the area of the eastern molasse either because of global sea level variation or as a result of regional tectonics this means that the occurrence of two sedimentary cycles in the western molasse and absence of the second cycle in the eastern molasse may be the result of shallower water depths and a lower subsidence rate in the area of the western molasse another interesting result from our studies relates to the sea level highstand and maximum extension of the upper marine molasse sea that based on our studies has occurred during the early ottnangian rather than during the middle ottnangian as suggested previously during this highstand the area of the eastern molasse displays a differentiation into a deep neritic basin facies characterised by high organic flux and moderate oxygen depletion at times and a marginal marine facies with well oxygenated environments the latter facies remained poorly understood until recently the entire region of the south german molasse basin was affected by a regression during the middle ottnangian this phase is characterised by unstable environmental conditions in the eastern molasse i e salinity fluctuations and temporarily strong oxygen depletion of bottom waters in the western molasse life conditions became even worse and as a result a drastic decline in marine life is observable

petrology mineralogy and geochemistry of the permian and triassic coals in the leping area jiangxi province southeast china abstract permian and triassic coals from a series of mines in jiangxi province china exhibit a number of unusual geochemical mineralogical and petrographic characteristics the high volatile bituminous permian coals have high concentrations of the suberinite like maceral barkinite the origin and even the distinct character of barkinite are in dispute and consequently it has not been recognized as a distinct maceral by the international committee for coal and organic petrology iccp the permian bituminous coals have relatively high concentrations of pyrite and marcasite otherwise detrital minerals dominate their geochemistry the triassic coals all from one mine complex have higher rank a permian coal is also mined most samples straddle the low volatile bituminous semi anthracite boundary the one semi anthracite rank permian coal shows signs of incipient coking a triassic coal in the same fault block is coked by an igneous intrusions found in the mine the coals have in general been dolomitized aside from the geochemical imprint of the dolomitization trace element associations suggesting a contribution from a detrital mineral assemblage dominate the coals

the last reconnection of the marmara sea turkey to the world ocean a paleoceanographic and paleoclimatic perspective during the late glacial marine isotope stage 2 the marmara sea transformed into a brackish lake as global sea level fell below the sill in the dardanelles strait a record of the basin s reconnection to the global ocean is preserved in its sediments permitting the extraction of the paleoceanographic and paleoclimatic history of the region the goal of this study is to develop a high resolution record of the lacustrine to marine transition of marmara sea in order to reconstruct regional and global climatic events at a millennial scale for this purpose we mapped the paleoshorelines of marmara sea along the northern eastern and southern shelves at cekmece prince islands and imrali using data from multibeam bathymetry high resolution subbottom profiling chirp and ten sediment cores detailed sedimentologic biostratigraphic foraminifers mollusk diatoms x ray fluorescence geochemical scanning and oxygen and carbon stable isotope analyses correlated to a calibrated radiocarbon chronology provided evidence for cold and dry conditions prior to 15 ka bp warm conditions of the bolling allerod from 15 to 13 ka bp a rapid marine incursion at 12 ka bp still stand of marmara sea and sediment reworking of the paleoshorelines during the younger dryas at 11 5 to 10 5 ka bp and development of strong stratification and influx of nutrients as black sea waters spilled into marmara sea at 9 2 ka bp stable environmental conditions developed in marmara sea after 6 0 ka bp as sea level reached its present shoreline and the basin floors filled with sediments achieving their present configuration

comparative studies of the kinetic parameters of various algaenans and kerogens via open system pyrolyses abstract kinetic parameters were determined for the first time via open system pyrolyses on algaenans highly resistant biomacromolecules that are selectively preserved during kerogen formation isolated from extant microalgae parallel studies were also carried out on 10 kerogens exhibiting with one exception a low level of maturity these kerogens included samples chiefly derived from the selective preservation of the above algaenans and samples mainly or almost exclusively derived from the natural vulcanization pathway important differences in activation energy e a distributions were observed between the four algaenans investigated and correlated with their chemical structures the kerogens predominantly derived from algaenan selective preservation pula alginite ne 70 and bj 248 torbanites rundle oil shale also exhibited pronounced differences in e a distributions these distributions provided i information on the diversity of the source materials and ii reflected the occurrence of important differences in chemical structures and thermal behaviour between three of the tested kerogens even though they are all classified as low maturity type i the kimmeridge clay samples and the lorca oil shale showed broad e a distributions shifted to low energies when compared with the above algaenans and kerogens such shifts reflect an important or even almost exclusive for some of these kerogens contribution of materials originating from sulphur incorporation into various lipids during early diagenesis finally the kinetic data derived for the nine low maturity fossil samples were extrapolated to a very low geological heating rate of 3 c ma 1 and the generation rate curves and cumulative yield curves thus obtained were compared

environmental changes of the last three centuries indicated by siliceous microfossil records from the southwestern baltic sea four short sediment cores from the southwestern baltic sea were analysed with respect to their content of siliceous microfossils the aim was to detect and date changes in the composition of the di

the last 1000 years of natural and anthropogenic low oxygen bottom water on the louisiana shelf gulf of mexico abstract the relative abundance of three species of low oxygen tolerant benthic foraminifers the peb index in foraminiferal assemblages from sediment cores is used to trace the history of low oxygen bottom water conditions on the louisiana shelf analyses of a network of box cores indicate that the modern zone of chronic seasonal hypoxia off the mississippi delta began to develop around 1920 and was well established by 1960 the pattern of development over the last century is consistent with the interpretation that the formation of modern chronic hypoxia is related to anthropogenic activities resulting in increased transport of nutrients to the louisiana shelf the peb index in two gravity and box core pairs mrd05 4 and 05 6 indicates that low oxygen bottom water events have occurred periodically on the louisiana shelf for at least the last 1000 14 c years the pre 1900 low oxygen bottom water events are likely caused by intervals of increased mississippi river discharge and widespread wetland export the peb record in gravity cores indicates that the pre 1900 low oxygen bottom water events were not as well developed or as geographically extensive as the modern hypoxia zone we conclude that the development of low oxygen bottom water on the louisiana shelf is a natural process that has been negatively modified by human activities in the last 100 years

earliest triassic claystone breccias and soil erosion crisis abstract chemostratigraphic methods 13corg for pinpointing the permian triassic boundary in nonmarine rocks of antarctica australia and south africa have drawn attention to unusual claystone breccias at this horizon of the greatest extinction in the history of life on earth these rocks differ from other breccias in having a high proportion of clasts with birefringence microfabrics sepic plasmic fabrics characteristic of soils and can be called sepic pedoliths in the terminology of soil science at many localities earliest triassic sepic pedoliths are thin 5 15 cm beds but some fill shallow paleochannels and pinch out laterally other non marine breccias at the permian triassic boundary are dominated by fragments of coal pedogenic carbonate nodules and deeply weathered volcanic rock fragments earliest triassic sepic pedoliths record an unusually severe and widespread episode of soil erosion associated with forest dieback at the permian triassic boundary comparable sepic pedoliths are found in debris flows after clear cutting of forests in western oregon today studies of these modern deposits show that sepic soil peds do not withstand weathering for more than a few months such clayey clasts are held together mainly by roots and fungi which decay rapidly in soils and streams these modern analogs demonstrate that terminal permian soil erosion was rapid and profound sepic pedoliths are also known at other times of mass extinction such as the triassic jurassic boundary but are not yet known before the devonian advent of trees and forested clayey soils

the northern coast of the ottnangian middle burdigalian early miocene molasse sea in germany sediments foraminiferal assemblages and biostratigraphy this study provides new data on the litho and biostratigraphy of the middle burdigalian ottnangian marine sediments at or close to the former northern coastline of the german molasse basin based on cores from three boreholes burgau hamlar 2 and lutzingen and two outcrops haunsheim and dattenhausen methods include quantitative analysis of benthic foraminiferal assemblages 90 samples studies of planktonic foraminifers and ostracods and investigations of lithofacies the data indicate that the transgressive regressive marine sediments of the upper marine molasse omm at burgau and hamlar 2 can be subdivided into the well known lower and middle ottnangian sedimentation cycles with the first cycle being represented by the omm basisschichten and kalkofen formation and the second by the baltringen and steinhofe formations we show for the first time that also the northernmost marginal marine omm facies lutzingen haunsheim and dattenhausen can be correlated with the lower and middle ottnangian sedimentation cycles consequently our results do not support the presence of a previously suggested third sedimentation cycle within the omm sediments our micropaleontological data reveal regionally diverse depositional environments reflecting different water depths and co varying environmental variables significant differences in abundance diversity and species composition of the benthic foraminiferal assemblages demonstrate marginal marine facies for lutzingen haunsheim and dattenhausen nearshore facies for hamlar 2 and shallow marine basin facies for burgau the characteristic lower ottnangian benthic foraminiferal species exhibit restricted ecological tolerances hence the absence or scarcity of these species in nearshore to marginal marine deposits has no stratigraphic significance the presence of two sedimentation cycles in the western german molasse basin alone may have resulted from the interplay of regional tectonics and basin development that have led to different rates of subsidence and sedimentation in the western and eastern sectors of the german molasse basin

seasonal oxygen depletion in continental shelf waters of louisiana historical record of benthic foraminifers a strong spring and summer oxygen depletion is induced in nearshore bottom waters of the louisiana continental shelf by density stratification and by the carbon flux from phytoplankton production which in turn is related to the nutrient load of the mississippi and atchafalaya rivers in an attempt to read the historical record of this shelf hypoxia during the past two centuries we compared the stratigraphic signals of benthic foraminifera as reflected in a relative dominance index for two common species of ammonia and elphidium in 210 pb dated cores and we found evidence of an overall rise in oxygen stress in intensity or duration especially in the past 100 yr this implies a progressive increase in the influence of river borne nutrients particularly anthropogenically influenced nitrates judging by our results foraminiferal indices based on appropriate species ratios should prove useful in testing hypotheses about long term environmental stresses including eutrophication and paleohypoxia on other marine shelves

the neogene genus streptochilus bronnimann and resig 1971 from the gulf of california abstract four species of the planktonic foraminiferal genus streptochilus from key neogene marine localities are documented in relation to the evolution of the gulf of california s globigerus s latus s macdougallae sp nov and s inglei sp nov planktonic foraminiferal bioevents and strontium isotopes in the bouse tirabuzon carmen and ojo de buey lithostratigraphic units constrain the local distribution range between 6 and 5 3 ma for the last three species whereas s globigerus appears locally at 5 5 ma and disappears between 3 79 and 3 46 ma in the imperial and trinidad formations the last occurrence of streptochilus latus and the first and last occurrences of s globigerus in the ancient gulf of california are correlated with bioevents calibrated in the equatorial pacific therefore they can be used as reliable local biostratigraphic markers the presence of streptochilus in the ancient gulf of california seems to correlate with upwelling in a pattern similar to that observed in the modern oceans

lateglacial and holocene environmental changes in portuguese coastal lagoons 2 microfossil multiproxy reconstruction of the santo andre coastal area benthic foraminiferal ostracod calcareous nannoplankton and diatom assemblages have been analysed from the 25 45 sedimentary succession of a borehole drilled in the santo andre lagoon southwestern portugal the zones and subzones recognized according to their microfossil content have been used to define six palaeoenvironmental stages extending from the lateglacial to the present stage a and the lower part of stage b 14 2 to 10 0 ka represent a postglacial terrestrial environment when sea level was below present following eustatic sea level rise a normal marine open bay environment established during the upper part of stage b 10 0 to 5 4 ka before 5 4 ka a coastal lagoon developed as a consequence of a sandy barrier formation since then natural variation in the permeability of the detrital barrier through time has been the primary control of the physical chemical and biological features of the lagoonal environment during stage c 5 4 to 3 6 ka as a freshwater dominated lagoon stage d 3

historical changes in terrestrially derived organic carbon inputs to louisiana continental margin sediments over the past 150 years 1 major rivers and associated deltaic environments provide the dominant pathway for the input of terrestrial derived organic carbon in sediments toct to the ocean natural watershed processes and land use changes are important in dictating the amount and character of carbon being buried on continental margins seven core sites were occupied on the louisiana continental margin aboard the r v pelican in july 2003 along two major sediment transport pathways south and west of the mississippi river mouth lignin profiles in these age dated cores 210pb geochronology indicate artificial reservoir retention as a primary control on organic carbon quantity and quality reaching the margin post 1950 whereas pre 1950 sediments may reflect soil erosion due to land clearing and farming practices lignin 8 concentrations range 0 2 to 1 7 also indicate that toct delivery rates decay processes have probably remained relatively consistent from proximal to distal stations along transects the down core profile at the canyon station seems to be temporally linked and connected to inner shelf deposition suggestive of rapid cross shelf transport sources of terrestrially derived organic carbon were reflective of mixed angiosperms over the last 150 years in cores west and south of the mississippi river delta the lignin phenol vegetation index lpvi range 130 0 to 510 proved to be a sensitive indicator of source changes in these sediments and eliminated some of the variability compared to c v range 0 01 to 0 4 and s v range 0 9 to 2 1 ratios stochastic events such as hurricanes and large river floods have a measurable albeit ephemeral effect on the shelf toct record burial of toct on the river dominated louisiana continental margin is largely driven by anthropogenic land use alterations in the last 150 years land use changes in the mississippi river basin and river damming have likely affected carbon cycling and toct burial on the louisiana continental margin over a large spatial extent as observed by similar trends in cores from across and along the margin

mineralization of ree y nb ta zr hf in wuchiapingian coals from the liupanshui coalfield guizhou southwestern china geochemical evidence for terrigenous input abstract abundances modes of occurrence enrichment and origin of critical elements in coal and coal bearing sequences have attracted much attention in recent years previous investigations have attributed ree y nb ta zr hf mineralization in coals and in intra and inter seam tuffs in coal bearing sequences to alkali volcanic ash eruptions and subsequent hydrothermal alteration in this study two major minable coal seams d101 and w407 that are located in the lowermost and uppermost wuchiapingian longtan formation in the liupanshui coalfield guizhou southwestern china were investigated in order to better understand the mechanism of ree y nb ta zr hf enrichment in these coals elevated concentrations of ree y nb ta zr hf in the d101 coal are dominantly due to the alkaline volcanic material forming the top of the emeishan large igneous province elip which served as a terrigenous source region for the coal basin and to airborne volcanic ash which occurs as an intra seam tonstein within the coal seam both of the two source materials were subsequently subjected to groundwater leaching resulting in redistribution of the rare earth elements and y rey leading to an uneven distribution of rey and zr along the studied coal seam sections the average rey oxides in the d101 and w407 coals are 2682 and 1260 ppm both on ash basis respectively and the outlook coefficients are 0 79 and 1 15 respectively indicating that both ashes from the two coals are potential raw sources for rey

the response of benthic foraminifera and ostracoda to heavy metal pollution in gulf of izmir eastern aegean sea benthic foraminifera can be used as environmental bioindicators especially in polluted environments where their sensitivity to pollutants may be expressed by a modification in the assemblage nineteen sediment samples were collected in november 2002 from surficial sediments of the gulf of izmir turkey the gulf of izmir is located in western turkey and surrounded by a densely populated community the gulf has been contaminated by numerous heavy metals but geochemical analyses have shown that metals are significant pollutants only in the inner part of the gulf outer and middle sections showed low levels of heavy metals except the estuary of gediz river eight heavy metals have been analyzed in all the sampling points sixty seven foraminifer and 22 ostracod species were identified in 16 sediment samples statistical analysis shows that there is a significant correlation between foraminifera species and heavy metals the most polluted inner sections are dominated by the tolerant species ammonia tepida that may be used as pollution indicator the gradient observed in heavy metal concentrations between the outer and inner sections has a prevalent influence on the foraminiferal distribution there is a gradient of the number of species increasing from the inner section toward the outer section the occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long term environmental impacts in a coastal region

foraminiferal records of bottom water oxygenation and surface water productivity in the southern japan sea during 160 15ka associations with insolation changes abstract analyses of the benthic and planktonic foraminiferal record were conducted to understand temporal variations in sea floor oxygenation and surface productivity during periods of dark layer deposition between 160 and 15 ka based on data from sediment core images md01 2407 water depth 932 m from the southern japan sea the dark layers in the core were classified into six types on the basis of benthic foraminiferal assemblages which reflect the nature and amount of organic material on the sea floor as well as the degree of oxygenation of bottom waters three of the dark layer types were deposited in conditions strongly associated with increased surface productivity which correlates with positive or negative peaks of summer insolation in the northern hemisphere during periods of insolation maxima summertime surface productivity was enhanced because of the inflow of nutrient rich surface waters associated with high precipitation in eastern asia caused by intensification of the east asian summer monsoon in contrast relatively sustained organic matter fluxes to the sea floor occurred during insolation minima possibly affected by active vertical mixing when the east asian summer and winter monsoons were both intensified in a given period well oxygenated bottom water environments combined with high surface productivity may have resulted in dark layer deposition because of a combination of strong wintertime water convection and increased summertime surface productivity it is likely that the organic carbon content of sediments underestimates surface productivity during depositional conditions favoring the sedimentary decomposition of organic matter

benthic foraminifers from the continental shelf and slope of the gulf of mexico an indicator of shelf hypoxia benthic foraminifers from 74 core top sediment samples collected primarily from the continental shelf of the gulf of mexico were analyzed to determine a microfaunal indicator for shelf hypoxia to be used in future paleoenvironmental studies principal component analysis pca and cluster analysis ca of 93 species recognized factors clusters that were similar to previous investigations of the benthic foraminifers except that both analyses also identified pca6 ca6 in the area where hypoxic conditions have been observed three low oxygen tolerant species pseudononion atlanticum epistominella vitrea and buliminella morgani have high factor loadings in pca6 the cumulative percentage of three species is defined as the peb peb pseudononion epistominella buliminella index the highest peb values observed in the 74 surface sediment samples occur in the zone of recognized hypoxia on the louisiana shelf values of the peb index are also elevated along the southern texas coastline suggesting that this area may experience periodic hypoxia as well

effects of surface orography and land sea contrast on the madden julian oscillation in the maritime continent a numerical study using echam5 sit abstractthis study uses the atmospheric general circulation model agcm echam5 coupled with the newly developed snow ice thermocline model echam5 sit to examine the effects of orography and land sea contrast on the madden julian oscillation mjo in the maritime continent mc during boreal winter the echam5 sit is one of the few agcms that realistically simulate the major characteristics of the mjo three experiments are conducted with realistic topography without orography and with oceans only in the mc region to evaluate the relative effects of orography and land sea contrast orography and land sea contrast have the following effects on the mjo in the mc 1 a larger amplitude 2 a smaller zonal scale 3 more realistic periodicity and stronger eastward propagating signals 4 a stronger southward detour during the eastward propagation 5 a distorted coupled kelvin rossby wave structure and 6 larger low level moisture convergence the existence of mountainous islands also enhances the mean w

the triassic timescale based on nonmarine tetrapod biostratigraphy and biochronology abstract the triassic timescale based on nonmarine tetrapod biostratigraphy and biochronology divides triassic time into eight land vertebrate faunachrons lvfs with boundaries defined by the first appearance datums fads of tetrapod genera or in two cases the fads of a tetrapod species definition and characterization of these lvfs is updated here as follows the beginning of the lootsbergian lvf fad of lystrosaurus the beginning of the nonesian fad cynognathus the beginning of the perovkan lvf fad eocyclotosaurus the beginning of the berdyankian lvf fad mastodonsaurus giganteus the beginning of the otischalkian lvf fad parasuchus the beginning of the adamanian lvf fad rutiodon the beginning of the revueltian lvf fad typothorax coccinarum and the beginning of the apachean lvf fad redondasaurus the end of the apachean beginning of the wasonian lvf near the beginning of the jurassic is the fad of the crocodylomorph protosuchus the early triassic tetrapod lvfs lootsbergian and nonesian have characteristic tetrapod assemblages in the karoo basin of south africa the lystrosaurus assemblage zone and the lower two thirds of the cynognathus assemblage zone respectively the middle triassic lvfs perovkan and berdyankian have characteristic assemblages from the russian ural foreland basin the tetrapod assemblages of the donguz and the bukobay svitas respectively the late triassic lvfs otischalkian adamanian revueltian and apachean have characteristic assemblages in the chinle basin of the western usa the tetrapod assemblages of the colorado city formation of texas blue mesa member of the petrified forest formation in arizona and bull canyon and redonda formations in new mexico since the triassic lvfs were introduced several subdivisions have been proposed lootsbergian can be divided into three sub lvfs nonesian into two adamanian into two and revueltian into three however successful inter regional correlation of most of these sub lvfs remains to be demonstrated occasional records of nonmarine triassic tetrapods in marine strata palynostratigraphy conchostracan biostratigraphy magnetostratigraphy and radioisotopic ages provide some basis for correlation of the lvfs to the standard global chronostratigraphic scale these data indicate that lootsbergian uppermost changshingian induan and possibly earliest olenekian nonesian much of the olenekian perovkan most of the anisian berdyankian latest anisian and ladinian otischalkian early to late carnian adamanian most of the late carnian revueltian early middle norian and apachean late norian rhaetian the triassic timescale based on tetrapod biostratigraphy and biochronology remains a robust tool for the correlation of nonmarine triassic tetrapod assemblages independent of the marine timescale

role of maritime continent land convection on the mean state and mjo propagation abstractthe maritime continent mc region is known as a barrier in the life cycle of the madden julian oscillation mjo during boreal winter the mjo detours the equatorial mc land region sout

propagating and nonpropagating mjo events over maritime continent abstractthe observed outgoing longwave radiation olr and era interim data during 1979 2008 from november to april were analyzed to reveal fundamental differences between eastward propagating ep and nonpropagating np mjo events across the maritime continent mc it was found that when the maximum mjo convection arrives near 120 e a positive moisture tendency lies in a longitudinal zone 10 s 10 n 130 170 e for the ep cases whereas a negative tendency appears in the same region for the np cases in the latter cases there are clearly detectable westward propagating rossby wave type dry signals over the equatorial central western pacific the dry rossby wave signal may hinder the development of new convection to the east of the mjo convective center preventing the eastward propagation of the mjo a moisture budget analysis shows that the positive tendency of specific humidity in the ep composite is mainly attributed to the advection of the mean moisture by an intraseasonal ascending motion ano

eastward propagating intraseasonal oscillation represented by chikira sugiyama cumulus parameterization part ii understanding moisture variation under weak temperature gradient balance abstractthe eastward propagating intraseasonal oscillation represented by the chikira sugiyama cumulus scheme in a general circulation model was investigated focusing on the variation of the free tropospheric humidity the net effect of the vertical advection and cloud process amplifies the positive moisture anomaly in the mature phase supporting the moisture mode theory the horizontal advection causes the eastward propagation of the field the variation of the moisture profile is accurately understood by using environmental vertical velocity outside cumuli the velocity is regulated by a thermodynamic balance under a weak temperature gradient a nondimensional parameter plays an important role in the moisture variation which characterizes the efficiency of moistening drying induced by external heating cooling in the middle and lower troposphere the major moistening factor is the radiative warming anomaly which induces the upward environmental vertical velocity anomaly the reevaporation of th

seasonality of the structure and propagation characteristics of the mjo the seasonality of the madden julian oscillation mjo is documented in observational data and a nonlinear shallow water model is used to help interpret some of the contrasts in mjo structure between the boreal winter season november march ndjfm and the asian summer monsoon period june september jjas at upper tropospheric levels the flanking rossby waves remain centered around 28 degrees n s year round but they tend to be stronger in the winter hemisphere where the climatological mean jet stream is stronger rendering the subtropical circulation more sensitive to forcing by a near equatorial heat source amplitudes of the mjo related deep convection and lower tropospheric zonal wind are stronger in the summer hemisphere where the column integrated water vapor is larger during ndjfm the equatorial asymmetry is subtle as in the annual mean moisture convergence into swallowtail shaped regions of enhanced deep convection is an integral part of the equatorial rossby wave signature and the eastward propagation is due to moistening of the air to the east of the enhanced convection by poleward moisture advection during the asian summer monsoon in jjas the convection assumes the form of northward propagating west northwest east southeast oriented rainbands embedded within cyclonic shear lines these features are maintained by frictional convergence of moisture and their northward propagation is mainly due to the presence of features in the climatological mean fields that is the west east moisture gradient over india and the arabian sea and the southwesterly low level monsoon flow over the northwest pacific

holocene geologic history of the golden horn istanbul nw turkey based on foraminiferal data abstract we evaluated foraminiferal data from holocene borehole samples of the golden horn istanbul nw turkey and the extrinsic factors controlling the distribution of microfaunas of the seaway system connecting the golden horn to the black and aegean seas samples were collected along two different transects one transect to the west between unkapani and azapkapi and a second transect to the east between eminonu and karakoy foraminiferal species distribution abundance and diversity exhibit a range of conditions from brackish to shallow water marine paleoenvironments during the last 7400 years the lithologic composition sedimentologic features and palynologic data indicate that freshwater paleoenvironments existed before the present marine conditions haurinid species are more abundant than rotaliids to the west unkapani azapkapi transect where gypsum crystals are also present rotaliids dominate to the east while textulariids are rare some typical foraminifera such as laevipeneroplis peneroplis sorites and amphistegina are of mediterranean origin observations on middle and upper holocene sediments prior to the last century were related to non polluted sediments including foraminifera and other fauna however anthropogenic effects during the last century caused the fauna to disappear from the polluted area foraminifera are now being found again in the golden horn embayment after the institution of anti pollution measures

mjo propagation across the maritime continent in the ecmwf ensemble prediction system abstractthe characteristics of the mjo propagation across the maritime continent are investigated using a 20 yr reforecast dataset from the ecmwf ensemble prediction system analysis of the mjo events initialized over the indian ocean phase 2 shows that the initial mjo amplitude and prediction skill relationship is not linear particularly when the predictions start in moderate between strong and weak mjo amplitude category to examine the key factors that determine the prediction skill reforecasts in the moderate category are grouped into high and low skill events and the differences in their ocean atmospheric conditions as well as the physical processes during reforecast period are examined the initial distribution of olr anomalies in high skill events shows a clear dipole pattern of convection with an enhanced convective anomalies over the indian ocean and strongly suppressed convective anomalies in the western pacific ocean this dipole mode may support the mjo propagation across the maritime

an idealized semi empirical framework for modeling the madden julian oscillation abstractthe authors present a simple semi empirical model to explore the hypothesis that the madden julian oscillation can be represented as a moisture mode destabilized by surface flux and cloud radiative feedbacks the model is one dimensional in longitude the vertical and meridional structure is entirely implicit the only prognostic variable is column water vapor w the zonal wind field is an instantaneous diagnostic function of the precipitation field the linearized version of the model has only westward propagating relative to the mean flow unstable modes because wind induced surface latent heat flux anomalies occur to the west of precipitation anomalies the maximum growth rate occurs at the wavelength at which the correlation between precipitation and surface latent heat flux is maximized this wavelength lies in the synoptic to planetary scale range and is proportional to the horizontal scale associated with the assumed diagnostic wind response to precipitation anomalies the nonlinear version

episodes of low dissolved oxygen indicated by ostracodes and sediment geochemistry at crystal lake illinois usa low dissolved oxygen during the summer and early fall controls profundal continental ostracode distribution in crystal lake mchenry county illinois favoring cypria ophthalmica and physocypria globula at water depths from 6 to 13 m these species also thrived in the lake s profundal zone from 14 165 to 9600 calendar year before present cal yr b p during the late bolling allerod and younger dryas chronozones and early holocene characterized by sand cemented tubules large aquatic gastropod shells and littoral ostracode valves thin 1 6 cm tempestite deposits punctuate thicker deposits of organic gyttja from 16 080 to 11 900 cal yr b p the succeeding 2300 yr 11 900 9600 cal yr b p lack tempestites and reconstructed water depths were at their maximum deposition of marl under relatively well oxygenated conditions occurred during the remainder of the holocene until the arrival of europeans when the lake returned to a pattern of seasonally low dissolved oxygen such conditions are also indicated in the lake sediment by the speciation of phosphorus high concentrations of organic carbon and abundant iron and manganese occluded to mineral grains initial low dissolved oxygen was probably caused by the delivery of dissolved p and fe in shallow groundwater the chemistry of which was influenced by spodosol pedogenesis under a spruce forest the triggering may have been regionally warm and wet conditions associated with retreat of the lake michigan lobe south central laurentide ice sheet

organic carbon production and preservation in response to sea level changes in the turonian carlile formation u s western interior basin abstract a primary sea level control over the distribution of total organic and carbonate carbon and organic matter type can be inferred in the early to middle turonian carlile formation fm western interior basin united states the conceptual model relies on chemo and lithostratigraphic correlations of lower to mid turonian strata in the central kwis supported by ammonite biostratigraphy and is based primarily on lithologic gamma ray spectrometric and geochemical facies analysis of the usgs portland no 1 core from central colorado the amoco rebecca bounds no 1 core from western kansas and the hawarden core from northwestern iowa sedimentation in the central marine axial basin of the cretaceous western interior seaway kwis during the turonian mostly reflects deposition by pelagic settling and from nepheloid layers with winnowing by bottom currents relatively high total organic carbon toc carbonate caco3 and rock eval pyrolysis hydrogen index hi values correspond to transgressive or highstand episodes within the overall regressive sequence whereas low values of these parameters characterize regressive intervals the lower fairport shale member of the carlile fm and coeval strata in iowa were deposited during a second order sea level highstand the waning stages of the greenhorn cyclothem an overall shallowing and coarsening upward sequence characterizes the overlying majority of the carlile fm this trend is punctuated by a short term transgressive episode with associated retrograde facies and a disconformity earlier studies document relatively high productivity during the turonian nutrient input to the seaway required to sustain water column productivity is difficult to account for solely by riverine inputs thus a model of transgressive flooding of preconditioned oxygen deficient nutrient rich water from the global ocean into the kwis is invoked this advection of nutrients and low oxygen water also helped to create broadly distributed dysoxic to anoxic conditions in the seaway which would otherwise have been difficult to maintain in a relatively well mixed shallow sea as the seaway regressed river supplied sea surface nepheloid layers provided sufficient nutrient inputs and occasionally established temporary stratification of the water column and thus contributed to maintaining an environment poised to produce and preserve organic matter

a unified moisture mode framework for seasonality of the madden julian oscillation abstractthe madden julian oscillation mjo exhibits pronounced seasonality while it is largely characterized by equatorially eastward propagation during the boreal winter mjo convection undergoes marked poleward movement over the asian monsoon region during summer producing a significant modulation of monsoon rainfall in classical mjo theories that seek to interpret the distinct seasonality in mjo propagation features the role of equatorial wave dynamics has been emphasized for its eastward propagation whereas coupling between mjo convection and the mean monsoon flow is considered essential for its northward propagation in this study a unified physical framework based on the moisture mode theory is offered to explain the seasonality in mjo propagation moistening and drying caused by horizontal advection of the lower tropospheric mean moisture by mjo winds which was recently found to be critical for the eastward propagation of the winter mjo is also shown to play a dominant role in operating t

a study of the kinetic parameters of individual macerals from upper permian coals in south china via open system pyrolysis abstract a unique upper permian coal leping coal is widely distributed in south china the coal samples studied in the paper were collected from two mines in the shuicheng coalfield of guizhou province southwest china the geochemical works including coal petrography maceral content rock eval pyrolysis and kinetic modelling of hydrocarbon generating have been carried out on whole coal and individual macerals the higher contents of volatile matter elemental hydrogen and tar yield and the high hydrocarbon generation potential of the leping coals are attributed to their high content of barkinite a special liptinite maceral the hydrocarbon generation potential of barkinite s2 287 mg g hydrogen index hi 491 mg g toc is greater than that of vitrinite s2 180 mg g hi 249 mg g toc and much higher than that of fusinite s2 24 mg g hi 35 mg g toc at the same experimental conditions barkinite has a higher threshold and a narrower oil window than those of vitrinite and fusinite and consequently can generate more hydrocarbons in higher coalification temperature and shorter geological duration data from the activation energy distributions indicate that barkinite has a more homogenous chemical structure than that of vitrinite and fusinite the above mentioned characteristics are extremely important for exploring hydrocarbon derived from the leping coals in south china

inner shelf paleoenvironmental evolution as a function of land ocean interactions in the vicinity of the guadiana river sw iberia this study investigates the land ocean interactions along the northern margin of the gulf of cadiz in the vicinity of the guadiana river benthic foraminifera and sedimentological characteristics were analysed in a sedimentary sequence spanning ca 5000 years core 8 22 m water depth retrieved from the inner shelf prodeltaic wedge the analyses were integrated in a temporal framework based on accelerated mass spectrometry radiocarbon dating paleoenvironmental changes and sediment transfer mechanisms from the continent to the shelf were investigated and related to climatic oscillations and anthropogenic impact in the region the results allowed the identification of two main periods of deposition the first period from ca 5150 cal bp core base to 1500 1200 cal bp is characterised by a mix of fine and coarse sediments relatively constant percentages of terrigenous and bioclasts and benthic foraminifera species characteristic of coastal environments these features indicate an environment strongly influenced by discharge from the guadiana river the second period from ca 1500 1200 cal bp to ca 200 cal bp core top is characterised by silt clay fraction dominated sediments an increase in terrigenous sediment towards the top and benthic foraminifera species characteristic of environments with low levels of energy an increase in the level of human occupation associated with changes in climate led to widespread erosion and soil loss to the continental shelf during this period with possible silting up of the guadiana eastern distributary allowing the transport of high amounts of sediment to the shelf by the western distributary that led to the enhancement of fine sedimentation and the formation of the prodeltaic wedge in the area of the studied core

propagation of the madden julian oscillation through the maritime continent and scale interaction with the diurnal cycle of precipitation the convectively active part of the madden julian oscillation mjo propagates eastward through the warm pool from the indian ocean through the maritime continent the indonesian archipelago to the western pacific the maritime continent s complex topography means the exact nature of the mjo propagation through this region is unclear model simulations of the mjo are often poor over the region leading to local errors in latent heat release and global errors in medium range weather prediction and climate simulation using 14 northern winters of trmm satellite data it is shown that where the mean diurnal cycle of precipitation is strong 80 of the mjo precipitation signal in the maritime continent is accounted for by changes in the amplitude of the diurnal cycle additionally the relationship between outgoing long wave radiation olr and precipitation is weakened here such that olr is no longer a reliable proxy for precipitation the canonical view of the mjo as the smooth eastward propagation of a large scale precipitation envelope also breaks down over the islands of the maritime continent instead a vanguard of precipitation anomalies of 2 5 mm day 1 over 10 6 km 2 jumps ahead of the main body by approximately 6 days or 2000 km hence there can be enhanced precipitation over sumatra borneo or new guinea when the large scale mjo envelope over the surrounding ocean is one of suppressed precipitation this behaviour can be accommodated into existing mjo theories frictional and topographic moisture convergence and relatively clear skies ahead of the main convective envelope combine with the low thermal inertia of the islands to allow a rapid response in the diurnal cycle which rectifies onto the lower frequency mjo hence accurate representations of the diurnal cycle and its scale interaction appear to be necessary for models to simulate the mjo successfully

prediction of the madden julian oscillation a review abstractthere has been an accelerating interest in forecasting the weather and climate within the subseasonal time range the madden julian oscillation mjo an organized envelope of tropical conv

reef shallowing is a critical control on benthic foraminiferal assemblage composition on nearshore turbid coral reefs abstract declining water quality represents a major threat to the coral reefs of australia s great barrier reef gbr due to their close proximity to river point sources reefs situated on the inner shelf of the gbr are widely perceived to be most susceptible to the increased discharge of nutrients and sediments from coastal catchments many of which have been modified since european settlement however the impact and magnitude of water quality change on the gbr s inner shelf reefs remains unclear much of the uncertainty can be attributed to a paucity of long term records with which to assess ecological and environmental change over appropriate reef building timescales here we present benthic foraminiferal palaeo records from three proximal nearshore turbid zone reefs located within the central region of the gbr bayesian age depth modelling was used to identify the core intervals corresponding to the timing of european settlement in the region c 1850 ce enabling the investigation of 1 the composition and variability of benthic foraminiferal assemblages during reef shallowing towards sea level and 2 whether any signal of increased nutrient and sediment inputs as the result of historical land use change can be discerned on the most nearshore reefs of the central gbr multivariate analyses identified two assemblage groups delineated by a significant increase in the relative abundance of pararotalia spp up core our results suggest that post european settlement associated increases in nutrient and sediment inputs are unlikely to have driven the observed shifts in benthic foraminiferal assemblage composition rather we interpret changes in the composition of benthic foraminiferal assemblages as being linked to changes in hydrodynamic energy light availability and the carbonate content of reef matrix sediments during reef shallowing towards sea level our findings support the hypothesis that nearshore turbid zone reefs have a higher resistance to increased nutrient and sediment inputs than those located further offshore towards the inner mid shelf boundary of the gbr

propagating versus nonpropagating madden julian oscillation events abstractbasinwide convective anomalies over the indian ocean io associated with the madden julian oscillation mjo sometimes propagate eastward and reach the west pacific wp but sometimes do not long term observations and reanalysis products are used to investigate the difference between the propagating and nonpropagating mjo events io convection onset events associated with the mjo are grouped into three categories based on the strengths of the simultaneous dry anomalies over the eastern maritime continent and wp the io convection anomaly preferentially makes eastward propagation and reaches the wp when the dry anomaly is stronger analysis of the column integrated moist static energy mse budget shows that horizontal advection moistens the atmosphere to the east of the positive mse anomaly associated with the active convection over the io and is of sufficient magnitude to explain the eastward propagation of the positive mse anomaly interpretation is complicated however by lack of closure in

ftir microspectroscopy of particular liptinite lopinite rich late permian coals from southern china abstract the late permian coals from southern china are unique in their high content of lopinite liptinite and elemental hydrogen and typically produce high yields of tar typical of the late permian coals of southern china the coals used in this study show special petrographic and chemical characteristics as well as significant oil producing potential studies of these coals and of their content of the lopinite maceral will help to explain the genesis of both the lopinite maceral and of the oil producing potential of the coals in this study an ftir spectrometer was used in the standard transmission mode to generate the ir spectra of the whole coal an ftir spectrometer equipped with a microscope in the reflectance mode was used to analyze the chemical structure of individual coal macerals including lopinite vitrinite semifusinite and inertinite the chemical structure of lopinite is characterized by its higher content of longer and less branched aliphatic side chains and distinct c 0 groups the oil producing potential of the coals is attributed to their higher content of lopinite

stratigraphic expressions of the holocene anthropocene transition revealed in sediments from remote lakes stratigraphic boundaries are ideally defined by distinct lithological geochemical and palaeobiological signatures to which a chronological framework can be applied we present a range of observations that illustrate how the holocene anthropocene transition meets these criteria in its expression in sediments from remote arctic and alpine lakes removed from direct catchment scale anthropogenic influences in glaciated lake basins the retreat of glaciers commonly leads to lithological successions from proglacial clastic sedimentation to non glacial organic deposition sediments from the majority of lakes record marked depletions in the nitrogen stable isotopic composition of sediment organic matter reflecting anthropogenic influences on the global nitrogen cycle in all cases siliceous microfossil assemblages diatoms and chrysophytes change markedly and directionally with regional nuances these stratigraphic fingerprints begin to appear in the sediment record after ad 1850 but accelerate in pulses between ad 1950 and 1970 and again after ad 1980 our review indicates that recent environmental changes associated with humankind s dominance of key global biogeochemical cycles are sufficiently pervasive to be imprinted on the sediment record of remote lakes moreover these changes are of sufficient magnitude to conclude that the holocene has effectively ended and that the concept of anthropocene more aptly describes current planetary dynamics the synthesis of these observations pertains directly to ongoing discussions concerning the eventual formalization of a new stratigraphic boundary

late quaternary micropalaeontological record of a semi enclosed marine basin north evoikos central aegean sea abstract north evoikos gulf constitutes a deep 450 m semi enclosed basin in east central greece connected to the aegean sea via a 42 m sill to the north and a 40 m wide 8 m deep channel to the south six gravity cores retrieved from different physiographic settings of the gulf were analyzed for their benthic foraminiferal content in order to reconstruct the local and regional palaeoenvironmental changes species correspondence analysis separates the foraminifera into 4 clusters cluster 1 is composed of agglutinated species elphidium spp and ammonia beccarii cluster 2 is exclusively composed of bulimina marginata cluster 3 consists of bolivina spathulata and bulimina costata and finally cluster 4 comprises the 10 remaining species cibicides lobatulus cibicidoides pachyderma bulimina aculeata cancris oblonga melonis barleeanum chilostomella oolina cassidulina laevigata hyalinea balthica and miliolidae these clusters represent four distinct foraminiferal biofacies and are interpreted as reflecting different ecological conditions biofacies p h corresponds to the proximal part of the shelf and it is characterised by the absence of foraminifera skeletal debris and abundant peloids its topmost part shows an erosional surface aged 32 4 ka characterised by shell debris and the appearance of few shallow marine benthic foraminifera biofacies ia and ib consist of a low diversity holocene assemblage which is mainly dominated by textularia spp and elphidium spp reflecting a low energy restricted lagoon and the deeper water assemblage of b marginata and h balthica biofacies ib as well as by a mollusc assemblage dominated by corbula gibba these biofacies are only present in the mid shelf setting biofacies ii cluster 3 b spathulata b costata shows a possible positive correlation with nutrient contents and it exhibits a complementary pattern of distribution with biofacies iii cluster 4 b marginata two main palaeoenvironmental settings were recognized a in the first setting dominated by biofacies ia and ib the succession of the benthic faunas is mainly controlled by the ongoing sea level rise b in the second setting the species typical of shelf environment c laevigata h balthica give way to opportunistic species b spathulata and species that are more resistant to bottom water changes b marginata this pattern is attributed to variations in the food chain and oxygenation north evoikos gulf during the uppermost quaternary reflects a passive response to a globally fluctuating sea level that was not significantly modified by dramatic tectonic processes therefore its palaeoceanographic evolution is primarily driven by climatic eustatic processes and accurately depicts local conditions

paleoceanographic changes on the farallon escarpment off central california during the last 16 000 years abstract new benthic and planktic foraminiferal assemblage census data and benthic foraminiferal oxygen index bfoi values previously published marine climate proxy data stable isotopes and ca cd and unpublished results of total carbon organic carbon and calcium carbonate analyses of sediments recovered off central california on the farallon escarpment 1605 m water depth 37 13 4 n 123 14 6 w core f 8 90 g21 document paleoceanographic changes during the latest quaternary which reflect the intensity and source of north pacific intermediate water npiw and surface productivity accelerator mass spectrometry radiocarbon dates of both benthic and planktic species provide an excellent age depth model for the last 16 000 years covering the latest glacial bolling allerod younger dryas and early middle and late holocene intervals a q mode cluster analysis separated the benthic fauna into three clusters one pleistocene and two holocene whereas the planktic fauna was divided only into pleistocene and holocene clusters stable oxygen isotope values show an increase in water temperature of 1 c from the late glacial to late holocene and a change in faunal composition of the planktic assemblage implies surface waters warmed as well a general trend of decreasing dissolved oxygen concentration from the pleistocene high oxic 3 0 6 0 ml l o2 to the holocene low oxic 1 5 3 0 ml l o2 suggested by the bfoi and cd ca data reflect decreased ventilation as the source of the npiw shifted from the sea of okhotsk to the tropical east pacific at 11 000 cal bp the middle holocene cooling reported in other central and northern california margin studies is not apparent in f 8 90 g21 which compares more favorably with studies from southern california and british columbia total carbon and organic carbon values are highest in the bolling allerod early holocene and late holocene similarly calcium carbonate values are high in the bolling allerod and peak in the early holocene but decrease significantly in the latest middle and late holocene which coincides with a depauparate planktic foraminiferal fauna in the upper 60 cm 70000 0 cal bp of the core and poor preservation of the benthic foraminiferal fauna at 40 cm 3000 cal bp decoupling is evident between the planktic and benthic faunal response to changing climatic conditions with the surface dwelling assemblage often leading the bottom dwelling assemblage by several millennia

a major change in the dinoflagellate cyst flora of gullmar fjord sweden at around 1969 1970 and its possible explanation

extrapolation of the kinetics of oil and gas formation from laboratory experiments to sedimentary basins it is generally accepted that the formation of oil and gas from sedimentary organic matter or kerogen is adequately described by kinetic models based on first order kinetics with rate constants obeying an arrhenius equation these models which are extensively used in oil exploration to assess the petroleum potential of sedimentary basins are based on geological observations1 2 3 4 5 6 but are formally quite similar to models designed to simulate oil shale pyrolysis7 8 9 or coal processing10 11 12 the idea of blending these two approaches is not new see for example ref 2 but until now the most sophisticated attempts reproduced only the gross features of kerogen cracking on a geological timescale5 or were uncontrolled by geochemical measurements13 14 here we show that the kinetic parameters determined from the laboratory pyrolysis of an immature kerogen sample apply to the conditions of sedimentary basins altough the time and temperature scale are completely different

coal petrology and the origin of coal macerals a way ahead the development of coal petrology and the establishment of a nomenclatural system have proved of major use both for the industrial utilization of coal and for the development of a broad understanding of coal formation and diagenesis the development over the past 30 years however of nomenclature that includes aspects of plant origin and process is a retrograde step e g pyrofusinite degradofusinite and funginite equally problematic is the use of prescriptive formulae to indicate coal origins this paper reviews some of the problems involved with coal petrology as it is usually practiced in addition new advances in organic geochemical techniques have led to a fuller understanding of the relationship of plants and coal macerals recent research on the origin of coal macerals is presented and there is a discussion of the problems and challenges facing coal petrologists a holistic approach to studies of the origin of coal and coal macerals which includes not only petrographic but also chemical and biological studies is advocated d 2002 elsevier science b v all rights reserved

striking liptinitic bark remains peculiar to some late permian chinese coals abstract an unusual liptinite coal component has been reported in the chinese literature over the past sixty years it has been described as a maceral in the chinese national standard 1991 but it has not been named internationally in chinese literature it is called barkinite on the basis of its morphological features and because it is believed to have originated as bark tissue barkinite occurs in late permian marine influenced coals and is best represented in the changguang leping and shuicheng basins of southern china the material originates from plant periderm or the bark of higher plants however bark contains a variety of substances including resin and suberin which are recognised as the precursors of the resinite and suberinite macerals barkinite is distinguished by i its thickness individual pieces can be more than ten cells thick and several centimetres long and ii it fluoresces strongly at 0 6 vitrinite reflectance and loses its fluorescence at about 1 1 vitrinite reflectance the reporting of barkinite from only chinese coals may be due to its origin from lepidodendron and psaronius flora which was common in the northern hemisphere during the carboniferous but which was isolated to china by the late permian it is proposed that the remnant flora evolved into unique forms in china by the late permian lepidodendron and psaronius remains coupled with a strongly marine influenced peat forming environment have given rise to barkinite and to its restricted distribution

foraminifera of petroleum platforms louisiana shelf gulf of mexico abstract species of benthic foraminifera presumably colonized the bacteria and diatom rich biofilms on the metallic surfaces of louisiana shelf petroleum platforms soon after their emplacement at present however most underwater platform legs are covered by a thick growth of macrofoulers predominantly barnacles and bivalves scraped samples from five such platforms water depth 16 61 m yielded 104 species of benthic foraminifera 44 of them with attached individuals among the obligate sessile species dyocibicides biserialis and planorbulina mediterranensis were especially widespread this group of epibionts also includes calcituba polymorpha carpenteria candei cornuspiramia antillarum lepidodeuterammina ochracea nubeculinita inhaerens planorbulina acervalis planorbulinoides retinaculatus sagenina divaricans webbina bonairensis and webbina rugosa the platforms are habitat islands the surrounding soft clastic substrate does not support the growth of most sessile species the putative source areas of these colonists of louisiana platforms are carbonate hardgrounds to the west banks or reefs formed over salt diapirs and other platforms the foraminiferal species diversity on the platforms is most likely controlled by their distances from these sources and the dimensions of the settlement surfaces the eastward transport of propagules in summer by the louisiana texas coastal current facilitates the species migration

comparison of kinetic analysis of source rocks and kerogen concentrates abstract shales and kerogen concentrates from the green river rundel ohio draupne and phosphoria formations were examined by pyromat ii micropyrolysis and kinetic parameters were determined by the shift in t max discrete distribution modified friedman and modified coats redfern methods overall the shales and corresponding kerogens exhibited very similar kinetic parameters green river rundel and ohio shales and kerogens exhibited principal discrete activation energies of 54 57 kcal mol narrow distributions and t max at 25 c min heating rate around 480 c draupne and phosphoria shales and kerogens exhibited kinetic parameters typical of type ii source rocks principal discrete activation energies of 54 57 kcal mol broad distributions and t max at 25 c min around 459 c the discrete distribution kinetic parameters were used to calculate oil generation at laboratory and geological heating rates each shale and corresponding kerogen exhibited generation curves and 50 generation temperatures that were very similar the principal difference was that the kerogens exhibited slightly more oil generation at low temperatures compared to the corresponding shales some kerogens exhibited curves which were also shifted to slightly lower temperatures than those of the corresponding shales for these specific shales and kerogens the results indicate that kerogen isolation does little to affect the pyrolysis kinetic parameters although from a limited number of samples these results suggest kerogen isolation may not be necessary to derive valid kinetic parameters

timing and magnitude of tetrapod extinctions across the permo triassic boundary a review of the tetrapod amphibian and amniote record across the permo triassic boundary ptb indicates a global evolutionary turnover of tetrapods close to the ptb there is also a within guadalupian tetrapod extinction here called the dinocephalian extinction event probably of global extent the dinocephalian extinction event is a late wordian or early capitanian extinction based on biostratigraphic data and magnetostratigraphy the extinction precedes the illawara reversal so it is not synchronous with the end guadalupian marine extinction the russian ptb section documents two tetrapod extinction events one just before the dinocephalian extinction event and the other at the base of the lystrosaurus assemblage however generic diversity across the latter extinction remains essentially the same despite a total evolutionary turnover of tetrapod genera the chinese and south african sections document the stratigraphic overlap of dicynodon and lystrosaurus in the karoo basin the lowest occurrence of lystrosaurus is in a stratigraphic interval of reversed magnetic polarity which indicates it predates the marine defined ptb so as previously suggested by some workers the lowest occurrence of lystrosaurus cannot be used to identify the ptb in nonmarine strata correlation of the marine ptb section at meishan southern china to the karoo basin based primarily on magnetostratigraphy indicates that the main marine extinction preceded the ptb tetrapod extinction event the ecological severity of the ptb tetrapod extinction event has generally been overstated and the major change in tetrapod assemblages that took place across the ptb was the prolonged and complex replacement of therapsids by archosaurs that began before the end of the permian and was not complete until well into the triassic the tetrapod extinctions are not synchronous with the major marine extinctions at the end of the guadalupian and just before the end of the permian so the idea of catastrophic causes of synchronous ptb extinctions on land and sea should be reconsidered

fundamental causes of propagating and nonpropagating mjos in mjotf gass models abstractthis study investigates the fundamental causes of differences in the madden julian oscillation mjo eastward propagation among models that participated in a recent model intercomparison project these models are categorized into good and poor groups characterized by prominent eastward propagation and nonpropagation respectively column integrated moist static energy mse budgets are diagnosed for the good and the poor models it is found that a zonal asymmetry in the mse tendency characteristic of eastward mjo propagation occurs in the good group whereas such an asymmetry does not exist in the poor group the difference arises mainly from anomalous vertical and horizontal mse advection the former is attributed to the zonal asymmetry of upper midtropospheric vertical velocity anomalies acting on background mse vertical gradient the latter is mainly attributed to the asymmetric zonal distribution of low tropospheric meridional wind anomalies advecting background mse and moisture fields base

topographic effects on the eastward propagation and initiation of the madden julian oscillation abstract this study investigates the relationship between deep convection and heating anomaly in the madden julian oscillation mjo and the tropical topography the eastward propagation of the deep heating anomalies is confined to two regions the indian ocean and the western pacific warm pool superimposed on the eastward propagation is a series of quasi stationary deep heating anomalies that occur sequentially and discretely downstream in a leapfrog manner in the central indian ocean the maritime continent tropical south america and tropical africa the deep heating anomaly usually preceded by near surface moisture convergence and shallow heating anomalies tends to occur on the windward side of the tropical topography in these regions except the central indian ocean under the prevailing surface easterly anomaly of the mjo it is suggested that the lifting and frictional effects of the tropical topography and landmass induce the near surface moisture convergence anomaly which in turn triggers

palaeoenvironmental indicators from late holocene and contemporary ostracoda of the aral sea abstract the aral sea is a large terminal lake i e having no outflow in south western asia it is diminishing in size and the salinity of the water is increasing due to excessive withdrawal of water for irrigation from the two main rivers flowing into it the biota of the lake has been decimated and the chemical composition changed dramatically since 1960 three short sediment profiles two cores and one section are examined with a view to reconstructing the most recent history of the sea from microfossil assemblages historical and geological records indicate that since its formation aral sea levels have changed such variation may have been accompanied by changes in the chemistry of the sea through increased evaporation or precipitation in the present work analyses of the mg ca and sr ca molar ratios particularly the latter of benthonic ostracoda from the aforementioned cores indicate that although present salinity levels were never attained during the period of deposition of the sections studied past saalinity variation can be inferred oxygen and carbon isotope analyses of ostracoda and mollusca from one of the sections however indicates two possible periods of relative salinity increase

effects of enhanced front walker cell on the eastward propagation of the mjo abstractwell organized eastward propagation of the madden julian oscillation mjo is found to be accompanied by the leading suppressed convection lsc over the maritime continent mc and the wes

barrier effect of the indo pacific maritime continent on the mjo perspectives from tracking mjo precipitation abstractexplanations for the barrier effect of the indo pacific maritime continent mc on the mjo should satisfy two criteria first they should include specific features of the mc namely its intricate land sea distributions and elevated terrains second they should include mechanisms for both the barrier effect and its overcoming by some mjo events guided by these two criteria a precipitation tracking method is applied to identify mjo events that propagate across the mc mjo c and those that are blocked by the mc mjo b about a half of mjo events that form over the indian ocean propagate through the mc most of them 75 become weakened over the mc the barrier effect cannot be explained in terms of the strength horizontal scale or spatial distribution of mjo convection when it approaches the mc from the west a distinction between mjo b and mjo c is their precipitation over the sea versus land in the mc region mjo c events rain much more over the sea than over land whereas rainfall over

eutrophication history of lake arendsee germany abstract at the maximum depth of lake arendsee 49 5 m only a thanatocenosis could be found in a freeze core with a length of 52 cm according to varve counting the fauna changed between 1960 and 1972 characteristic of mesotrophic to eutrophic state the cause for eutrophication could be correlated with the sewage loading of the town of arendsee and the drainage of lake fauler see into lake arendsee lake arendsee did not yet recover from the loading because of the long retention time of 114 years the investigation of the living meio and macrobenthos of lake arendsee shows that the lower profundal is not colonized

dinoflagellate cysts as indicators of pollution and past climate in a norwegian fjord two sediment cores from a semi enclosed eutrophic fjord and one from the open adjoining fjord revealed a sequence of dinoflagellate cyst assemblage changes during the past 1000 years higher percentages of the warmer water cyst lingulodinium machaerophorum deflandre and cookson wall 1967 10 41 within the restricted fjord correspond with the medieval warm period and is succeeded by decreased percent ages 5 from about ad 1380 corresponding with the onset of the more adverse climate of the little ice age two peaks of operculodinium centrocarpum deflandre and cookson wall 1967 at about ad 1700 followed by decreased total cyst concentrations in the enclosed fjord and increased total cyst concentrations in the open fjord is used to correlate cores from the two fjords and suggests climatic change increased pollution from sewage discharge as the human population of the city of bergen expanded is suggested by decreased total cyst concentrations cyst g dry sediment accompanied by peak concentrat

recent eutrophication and consequent hypoxia in the bottom waters of the lower st lawrence estuary micropaleontological and geochemical evidence micropaleontological and geochemical analyses were carried out on two sediment box cores ah00 2220 and cr02 23 recovered in the lower st lawrence estuary lsle in order to document recent temporal variations of primary productivity and carbon fluxes to the bottom waters these reveal a ten fold increase in the accumulation rate of dinoflagellate cysts and benthic foraminifera in the sediment over the last four decades which can be interpreted as a recent increase in pelagic and benthic production furthermore the appearance of the benthic foraminiferal species brizalina subaenariensis and bulimina exilis which are tolerant of low oxygen concentrations and high organic fluxes in the upper 20 cm of the cores may reflect significant changes in bottom water conditions over the last 40 yrs variations in the microfossil abundances in core ah00 2220 are strongly correlated with an increase in organic carbon oc content from 1 1 to 1 6 and to a shift in the isotopic signature of the latter 13 corg from 24 8 to 24 0 similarly a concomitant decrease in the corg n ratio from 15 to 12 an increase in organic carbon content from 1 3 to 1 9 and an increase in 13 corg from 24 5 to 23 5 were observed in core cr02 23 all of which suggest an enhanced accumulation of marine over terrestrial oc in the lsle our results imply that a significant increase in marine productivity in the lsle occurred since the 1960 s 2006 elsevier b v all rights reserved

abrupt and gradual extinction among late permian land vertebrates in the karoo basin south africa the karoo basin of south africa exposes a succession of upper permian to lower triassic terrestrial strata containing abundant terrestrial vertebrate fossils paleomagnetic magnetostratigraphic and carbon isotope data allow sections to be correlated across the basin with this stratigraphy the vertebrate fossil data show a gradual extinction in the upper permian punctuated by an enhanced extinction pulse at the permian triassic boundary interval particularly among the dicynodont therapsids coinciding with negative carbon isotope anomalies

geology of mankind for the past three centuries the effects of humans on the global environment have escalated because of these anthro pogenic emissions of carbon dioxide global climate may depart significantly from natural behaviour for many millennia to come it seems appropriate to assign the term anthropocene to the present in many ways human dominated geological epoch supplementing the holocene the warm period of the past 10 12 millennia

petrologic and geochemical characteristics of barkinite from the dahe mine guizhou province china abstract although barkinite has long been studied by many geologists its geochemical characteristics and environment of deposition are still not known in detail in order to study the petrography and geochemical characteristics of barkinite coal samples from two permian coal seams were taken from the dahe mine guizhou province the samples were separated into maceral fractions and then analyzed by microscopical isotopic rock eval and geochemical methods the microscopical results indicate that barkinite occurs as four main types according to their relationship to other maceral groups barkinite is ostensibly formed under variably dry wet or oxidizing reducing conditions the extract yield isotope data and rock eval values of barkinite are different from other macerals microscopical and geochemical results indicate that barkinite forms part of the liptinite group

topographic influence on the mjo in the maritime continent abstract this study demonstrates that during the passage of the mjo through the maritime continent in the boreal winter the corresponding deep convection and near surface wind anomalies tend to skirt around mountainous islands flow bifurcation around elongated mountainous islands such as new guinea is clearly seen topographic blocking generates distinctive vorticity and convergence distributions in this specific domain mountain wave like structures are also observed throughout the maritime continent with a clear spatial relationship with the high terrains in sumatra sulawesi and new guinea the existence of topography seems to create extra lifting and sinking within the large scale circulation and thus the convective system exhibits quasi stationary features near the major topography during the mjo passage through the maritime continent it is suggested that resolving the detailed topographic effects may play a key role in simulating realistic characteristics of the mjo in the maritime continent

why does the mjo detour the maritime continent during austral summer eastward propagation of the madden julian oscillation mjo detours the maritime continent mc region southward during austral summer exhibiting enhanced convective activity preferentially in the southern part of the mc area with much weaker anomalies in the central mc area column integrated moist static energy budget of the mjo is analyzed to understand the processes responsible for the mjo detouring results show that zonal and meridional moisture advection is the essential process to the mjo detouring causing the difference between the southern and central mc regions in the moisture recharge before and during the mjo onset further analysis reveals that moisture advection by mjo perturbation winds acting upon the background moisture gradient has the dominant contribution to the regional contrast between the central and southern mc areas the zonal moisture advection is greater in the southern mc region because the zonal gradient of the background moisture field is much steeper in the southern mc area than in the central mc area the onset of the australian monsoon in austral summer contributes to the establishment of the sharp zonal moisture gradient in the southern mc region the meridional moisture advection is weaker in the central mc area because meridional wind anomalies associated with the mjo vary regionally presumably through interactions with the topography and land sea contrast

a unified convection scheme unicon part i formulation abstractthe author develops a unified convection scheme unicon that parameterizes relative i e with respect to the grid mean vertical flow subgrid vertical transport by nonlocal asymmetric turbulent eddies unicon is a process based model of subgrid convective plumes and mesoscale organized flow without relying on any quasi equilibrium assumptions such as convective available potential energy cape or convective inhibition cin closures in combination with a relative subgrid vertical transport scheme by local symmetric turbulent eddies and a grid scale advection scheme unicon simulates vertical transport of water species and conservative scalars without double counting at any horizontal resolution unicon simulates all dry moist forced free and shallow deep convection within a single framework in a seamless consistent and unified way it diagnoses the vertical profiles of the macrophysics fractional area plume radius and number density as well as the microphysics production and evaporati

impact of rossby and kelvin wave components on mjo eastward propagation abstractthere are contrasting views concerning the impact of rossby wave component of mjo flow on its eastward propagation one view called drag effect argues that because rossby waves propagat

microbiotic signatures of the anthropocene in marginal marine and freshwater palaeoenvironments the term anthropocene has been proposed to indicate a geological interval character ized by global anthropogenic environmental change this paper attempts to recognize a method by which the anthropocene can be defined micropalaeontologically in order to do this microfloras and microfaunas diatoms macrophytes dinoflagellate cysts foraminifera and ostracods from nearshore waters through to paralic and freshwater aquatic milieux are considered and biotic varia bility with an anthropogenic causation identified microbiotic change can be related to anthropo genically induced extinctions pollution related mutation environmentally influenced assemblage variability geochemistry of carapaces tests floral change related to lacustrine acidification faunal and floral correlation to industrial and agricultural signatures and introduction of exotic species via shipping the influence of humanity on a local scale can be recognized in assemblages as far back as 5000 years bp however widespread anthropogenic change took place in europe and america particularly in the nineteenth and twentieth centuries although in asia e g japan it cannot be observed prior to the twentieth century profound and global biotic change began in the mid twentieth century and if the anthropocene is to be defined in this way then the period 1940 1945 might encompass the biotic base of the interval

interaction between sedimentary processes historical pollution and microfauna in the tinto estuary sw spain the analysis of a short core collected in the tinto estuary sw spain permits to delimitate the influence of historical mining activities on sediments and microfauna foraminifera and ostracoda in very shallow palaeochannels of the middle estuary a first mining period 3 600 cal years bp caused high sediment pollution by cu with a significant diminution of the palaeontological record due to continuous acid mining drainage processes in this core the polluted levels derived from both roman extractions 2 000 1 900 years bp and the extensive mining activities between 1870 and 1935 have been eroded the 1 800 200 years bp period is characterized by a limited mining activity and an important improvement of this ecosystem in addition the effects of recent industrial wastes have been limited in this area

key processes for the eastward propagation of the madden julian oscillation based on multimodel simulations as a prominent climate variability mode with widespread influences on global weather extremes the madden julian oscillation mjo remains poorly represented in the latest generation of general circulation models gcms with a particular challenge in simulating its eastward propagating convective signals in this study by analyzing multi model simulations from a recent global mjo model evaluation project an effort is made to identify key processes for the eastward propagation of the mjo through analyses of moisture entropy me processes under a moisture mode framework for the mjo the column integrated horizontal me advection is found to play a critical role for the eastward propagation of the mjo in both observations and good mjo models with a primary contribution through advection of the lower tropospheric seasonal mean me by the mjo anomalous circulations by contrast the horizontal me advection effect for the eastward propagation is greatly underestimated in poor mjo gcms due to model deficiencies in simulating both the seasonal mean me pattern and mjo circulations leading to a largely stationary mjo mode in these gcms these results thus pinpoint an important guidance towards improved representation of the mjo in climate and weather forecast models while this study mainly focuses on fundamental physics for the mjo propagation over the indian ocean complex influences by the maritime continent on the mjo and also me processes associated with the mjo over the western pacific warrant further investigations

150 years of eutrophication in the northern adriatic sea evidence from a benthic foraminiferal record the vertical distribution of benthic foraminifera in a sediment core in front of the po delta has been studied in detail according to our age model based on 210pb and 137cs analyses of another core from exactly the same locality the studied core spans the past 160 years the radio isotope profiles further show that sediment mixing is largely restricted to the top centimeter suggesting that the core should provide an extremely detailed record of the youngest history of the northern adriatic sea benthic foraminiferal patterns and grain size analyses indicate a number of substantial changes in sedimentation rate and food oxygen availability in the benthic ecosystem changes occurring at about 1840 and 1880 can be attributed to man induced changes in the main outflow canals of the po river the first one led to an important reduction of the marine vegetation cover which probably was present up to that date the second change resulted in the present day situation in which the po outflow is passing the studied core locality close by the local benthic foraminiferal associations indicate a steadily increasing nutrient load from 1900 ad onwards this trend is interpreted as the effect of anthropogenic eutrophication due to agriculture and waste water disposal although the faunal record as discussed here only gives a limited impression of the basin wide development a marked faunal transition around 1930 indicates intensification of the eutrophication around 1960 the first signs of an increasing importance of anoxic events can be recognized the faunal changes in the last decade which are ascribed to changes in preservation potential indicate that more intense or more prolonged anoxia started about 10 years ago and that the ecological health of this part of the northern adriatic probably is still in decline

vertebrate extinction across permian triassic boundary in karoo basin south africa distinct assemblages of paleosols above and below the permian triassic boundary in the karoo basin of south africa are evidence for reorganization of ecosystems following this greatest of all mass extinctions the permian triassic boundary is recognized from the last appearance of dicynodon and from a series of negative excursions in the isotopic composition of carbon within therapsid tusks pedogenic carbonate nodules and organic matter the boundary is also marked by laminated beds with very weakly developed paleosols a change from purple 10r to brownish red 2 5yr paleosols and a thin 10 cm claystone breccia of reworked soil clasts paleoclimatic changes include a shift from arid and highly seasonal paleoclimate inferred from diffuse and shallow calcareous nodules in permian paleosols to semiarid and less seasonal paleoclimate inferred from deep and well focused calcic horizons in triassic paleosols an earliest triassic shift to warmer and wetter paleoclimate is also indicated by increased chemical weathering abundance of lycopsids and diversity of labyrinthodonts permian paleosols have root traces comparable to those of open shrubland and riparian woodland whereas triassic paleosols have root traces and profile forms like soils of open woodland this is a significant paleoenvironmental change but not as dramatic a change as would be expected from the devastating extinctions of 88 of fossil vertebrate genera latest permian therapsid reptiles were diverse and ecologically specialized in contrast the principal earliest triassic therapsid lystrosaurus was a burrower with no specific habitat preference its short internal nares barrel chest and high neural spines would have given it greater aerobic scope than preexisting therapsids and may have been an advantage under conditions of hypercapnia and hypoxia these adaptations and associated ecosystem changes are compatible with widespread vertebrate mortality by acidosis and pulmonary edema in a post apocalyptic greenhouse created by the voluminous release of methane from shallow marine and permafrost clathrates

state of the art of research in kinetic modelling of oil formation and expulsion abstract the last ten years have seen a rapid development in the understanding of petroleum generation and expulsion by a combined use of natural series and experimental simulation this knowledge is now used to develop mathematical models which reproduce the kinetics of petroleum generation and migration in the purpose of basin evaluation by a combination of observation of homogeneous geochemical series experimental simulation and mathematical modelling it has been now established that parameters governing the quantity and composition of petroleum are temperature type of organic matter time or heating rate catalysis by clay minerals which would produce important amounts of isoalkanes is not necessary to produce petroleum the role of minerals although still controversial is rather to retain the heavy fraction of petroleum pressure seems to have a limited influence within the range for effective source rocks kerogen is a tremendously complex macromolecule which is now insufficiently characterized to develop fundamental predictive models of thermal cracking i e involving intermediates such as radicals and olefins such models presently apply only to the cracking of simple molecules hexane hexadecane at limited degrees of cracking for this reason kinetic models are still empirically calibrated on pyrolysis experiments and or on natural maturation trends the most popular models involve a series or a continuous distribution of parallel reactions to describe primary cracking i e direct formation of mobile compounds from kerogen these are generally calibrated against open system pyrolysis with various temperature programs consideration of natural maturation trends i e decrease in petroleum potential may be used also for calibration but discrepancies of organic matter properties availability of deep samples and uncertainties on thermal history limit the effectiveness of such methods whatever the method main activation energies are found in the range 45 60 kcal mol secondary cracking which refers generally to cracking of mobile compounds cannot be modelled from open system pyrolysis nor from natural series unknown residence times but only from closed system pyrolysis although models of primary and secondary cracking still need experimental improvements and more realistic kinetic schemes their ability to predict quantities and composition of petroleum depends primarily on migration which is poorly known indeed migration controls the residence time of petroleum in hot zones of sedimentary basins and thus determines the extent of oil conversion into gas as reproduced by recent numerical models preliminary studies documenting the interactions between thermal cracking and expulsion are shown from haltenbanken area and paris basin in the last few years a kind of agreement has been reached that primary migration was most likely occuring in a separate phase from water and that a sufficient concentration of petroleum must be generated for expulsion to start indeed high expulsion efficiencies over 50 are systematically found for rich and mature source rocks a further understanding of primary migration requires observations of natural series petrophysical studies of source rocks porosities under 10 permeabilities in the nanodardy range thermodynamic investigation of unconventional multiphase organic systems kerogen liquid s gas and experimental simulation under stress this on going research should enable models to track correctly migration paths and thermal history of petroleum fluids as necessary to model their composition

the evolution of hypoxia off the changjiang estuary in the last 3000 years evidence from benthic foraminifera and elemental geochemistry abstract estuarine hypoxia has exerted great influence on the ecological system and fishery production in the past decades consequently attracting intensive concern in this study the upper 18 0 m of core yd0902 retrieved from the hypoxic area off the changjiang estuary was dated by ams 14c method and analyzed with lithology grain size benthic foraminifera and geochemical elements to decipher the paleoenvironmental change and hypoxic history in the last 3000 years the core location was in the neritic to prodelta transitional environment during 3000 2160 cal yr bp and the delta front environment after 2160 cal yr bp no hypoxia occurred during 3000 2600 cal yr bp potentially related to the contemporary occurrence of a rapid cold climate event in the northern hemisphere hypoxia has likely existed persistently since 2600 cal yr bp the period 2600 600 cal yr bp characterizes persistently severe hypoxia mainly linked with the warm climate strong east asian summer monsoon easm and rainfall intensified taiwan warm current intrusion and upwelling and high primary production lessened hypoxia followed in the period 600 260 cal yr bp because of the cold climate weak easm and minor precipitation the recent period post 260 cal yr bp was not disclosed by the core due to lost sediments in the top 4 5 m and could only be surmised to have severe hypoxia because of climate factors similar to the period 2600 600 cal yr bp our findings shed new light on long term hypoxic evolution and controlling factors in mega river estuaries

bottom water oxygenation and environmental change in santa monica basin southern california during the last 23 kyr abstract the southern california borderland is a region that experiences strong natural variations in bottom water oxygen and ph we use marine sediments from santa monica basin to reconstruct environmental conditions in the basin s bottom water from the last glacial maximum lgm to present we then compare the records to the adjacent santa barbara basin and santa lucia slope high resolution records of benthic foraminiferal oxygen and carbon isotopes 18o and 13c benthic foraminiferal assemblages and bulk sedimentary organic matter geochemistry records exhibit major changes associated with late quaternary millennial scale global climate oscillations our data show the dominance of low oxygen benthic foraminiferal assemblages during warm intervals and assemblages representing higher dissolved oxygen during cooler intervals as also seen in santa barbara basin and santa lucia slope however our record shows a stronger and longer lasting oxygen minimum zone omz between the mid younger dryas yd and the early holocene than at neighboring sites indicated by dominance of bolivina tumida characteristic of major hypoxia in the assemblage the middle to late holocene from 9 to 0 kyr had weaker hypoxia than the early holocene with assemblages mainly composed of bolivina argentea and uvigerina peregrina santa monica basin remained slightly hypoxic throughout the past 23 kyr however differences in the degree of hypoxia from santa barbara basin and santa lucia slope especially from the b a to the early holocene are seen the santa monica basin bottom water is affected by regional processes such as changes in the source of intermediate water and or changing ventilation oxygenation of the intermediate water source this is due to the greater depth and the more southern geographic position of the basin which reduces exposure to the oxygenated north pacific intermediate water current additional local processes also affect the basin such as the effects of sediment influx from submarine canyons this analysis utilizing parallel geochemical and micropaleontological records brings new insights into bottom water and climate conditions in santa monica basin indicating regional similarities and differences from adjacent basins and provides insight into the causes for changes in bottom water oxygenation

changes in the composition of the diatom flora during the last century indicate increased eutrophication of the oder estuary south western baltic sea four short sediment cores from the oder estuary south western baltic sea were studied with respect to their siliceous microfossil and organic carbon content the sediments were dated by pb 210 t

reconstructing a 180 yr record of natural and anthropogenic induced low oxygen conditions from louisiana continental shelf sediments hypoxia on the louisiana continental shelf is tied to nutrient loading and freshwater stratification from the mississippi river variations in the relative abundance of low oxygen tolerant benthic foraminifers in four sediment cores from the louisiana shelf provide a proxy record of low oxygen events core chronologies are obtained using 2 1 0 pb dating techniques the foraminiferal data are consistent with previous studies indicating that the intensity of hypoxic events oxygen 2 mg l has increased over the past 50 yr owing to the higher nutrient loading associated with the use of commercial fertilizer and also reveal several low oxygen events between a d 1817 and 1910 prior to the widespread use of fertilizer the pre 1910 low oxygen events are associated with high mississippi river discharge rates indicating that these low oxygen episodes are related to natural variations in river drainage that enhance transport of nutrients and freshwater to the continental shelf our data show that the low oxygen events of the past few decades were more extreme than any that occurred in the previous 180 yr and support the interpretation that the increased use of fertilizer has amplified an otherwise naturally occurring process