estimating internal wave spectra using constrained models of the dynamic ocean multi channel seismic method mcs with its ability to image events down to a lateral resolution of 10 m has been successfully applied to address questions in physical oceanography however to date these analyses have overlooked an important detail the imaged boundaries are dynamic and move on a timescale that can be resolved by the mcs method an important step in understanding the effect of the movement is calibration against constrained models we demonstrate in this paper that it is possible using careful interpolation to take high resolution models of dynamic water 160 m x 2 m spatial resolution and 15 min temporal resolution and generate models for synthetic seismic simulations 20 m x 4 m spatial resolution and 20 sec temporal resolution we show that moving water when ignored will distort analyses of wavenumber spectra estimated from seismic data since the relative movement of water masses and the seismic acquisition vessel will change the apparent slope of spectra citation vsemirnova e r hobbs n serra d klaeschen and e quentel 2009 estimating internal wave spectra using constrained models of the dynamic ocean geophys res lett 36 l00d07 doi 10 1029 2009gl039598

t max of asphaltenes a parameter for oil maturity assessment abstract a new maturity parameter determined on both oil and bitumen samples the asphaltene tmax is proposed and discussed this parameter could be very useful to address the maturity of the source rock the asphaltene tmax is measured by programmed rock eval pyrolysis using a modified temperature program some phases of the experimental procedure such as the asphaltene preparation and the rock eval measurement substratum choice are crucial in order to achieve reliable data laboratory simulations were carried out in order to assess the possible effects of both primary and secondary migration on asphaltene tmax in the expelled oil the original value of the asphaltene tmax in the bitumen is not substantially modified and it is very close to that measured on kerogen examples of the determination of asphaltene tmax on many samples collected from different areas and with different organic matter composition are given results show that tmax values from oil asphaltenes are reasonable indicators of source rock maturity

long period lunar tides at the south pole vertical gravity data from 6 3 years of observations at the geographic south pole have been analyzed to determine the gravimetric factor and phase angle of the long period tides annual and semiannual tides are obscured by the combination of signals arising from instrumental drift and the large annual component of barometric pressure changes at pole gravimetric factors for the three major long period tides are m 1 1589 0 0017 mm 1 1406 0 0085 and mtm 1 1692 0 0068 the only statistically significant phase shift is for the fortnightly component 0 0151 0 0032 days a phase lead our data analysis for the gravitational factor for m at the south pole indicates that the calculation of the influence of the long period ocean tides on the earth tides at the south pole should be reconsidered

influence of water column anoxia and sediment supply on the burial and preservation of organic carbon in marine shales abstract previous work has suggested that the laminated organic rich and bioturbated organic poor shales of the camp run member of the late devonian early mississippian new albany shale formed under anoxic and oxygenated bottomwater conditions respectively and that the interbedding of the two facies was due to the vertical oscillation of a water column anoxic oxic boundary where it impinged on the basin margin we have extended this analysis by examining the chemical and mineralogical differences between the two shale facies in a single borehole core by seeking evidence for deposition of the laminated shales under bottom water oxia or anoxia and by determining whether the laminated shales formed when the carbon supply to the sea floor was higher the results of this study show that the laminated and bioturbated shales are mineralogically and chemically distinct relative to al an index of the aluminosilicate content si ti fe p na ba co cr cu mo ni v zn and zr are all higher whereas mn ca mg and sr are lower in the laminated compared with the bioturbated shales the differences are due to a higher quartz feldspar titanite ilmenite and zircon content in the laminated shales probably indicating a coarser grain size and the greater abundance of manganoan calcite in the bioturbated shales dissolved oxygen was present in bottom waters during the deposition of some of the laminated shale intervals because of the presence of manganoan calcite a phase that can only form in sediments with an oxic surface in addition the organic matter preserved in the two shale types is isotopically different 13corganic values are 1 9z permil lighter on average in the laminated compared with bioturbated intervals possibly indicating a larger fraction of terrestrial organic matter in the latter 15n values are 1 9z permil lighter on average in laminated compared with bioturbated intervals possibly indicating a larger fraction of terrestrial organic matter in the latter 15n values are 1 9z permil lighter on average in laminated compared with bioturbated intervals suggesting that nutrient drawdown was less during the deposition of the organic rich laminated shales the chemical mineralogical and isotopic contrasts between the two shale facies of the camp run member indicate that the conditions of sedimentation were different during their deposition the difference was possibly related to variations in sea level which would have caused the camp run shoreline to move closer to and farther from the core site causing in turn the deposition of coarser and finer grained sediments that contained different mixtures of marine and terrestrial organic matter bottomwater conditions were anoxic during deposition of most laminated intervals bottom water anoxia or dysoxia led to decreased burial and preservation of the essential nutrient phosphorus in the laminated organic rich shales relative to the rocks deposited beneath better oxygenated bottomwaters increased availability of phosphorus in the water column on long timescales leads to increased productivity and a higher settling flux of organic matter causing bottom water oxygen levels to fall this is consistent with the nitrogen isotope evidence suggesting that production was probably higher during the deposition of the organic rich shales thus production variations coupled with enhanced sedimentary regeneration of phosphorus from sediments related to low oxygen bottom water concentrations provide a general mechanism for the formation of the alternating facies of this member of the new albany shale

biomarkers of oligocene lacustrine source rocks beibuwan song hong basin junction offshore northern vietnam abstract highly oil prone source rocks containing sapropelic type i and mixed types i and iii kerogen are found in 233 m of the 500 m deep fully cored enreca 3 well drilled on bach long vi island located at the junction between the beibuwan and the song hong basins offshore northern vietnam the cored succession is made up entirely by oligocene deep lacustrine deposits the origin of the organic matter om in 62 samples is evaluated on the basis of gas chromatography mass spectrometry gc ms and gc ms ms om in 55 samples is sourced primarily from lacustrine organisms and contains abundant 4 methylsteranes tetracyclic polyprenoids tpp and lycopane and no markers for marine organic matter the proportion of triterpanes derived from angiosperms is low in most saturated fractions and only traces of gymnosperm diterpanes are detected in contrast all aromatic fractions have a high proportion of compounds having an origin from both gymnosperms and angiosperms very high concentrations of hopanoids in both fractions suggest significant bacterial alteration of the original om most samples have a high concentration of rare c31 diaromatic 8 14 secohopanes with a fluorene moiety low pristane phytane pr ph ratios indicate that anoxic suboxic bottom water conditions existed during om accumulation the presence of carotane gammacerane and traces of arylisoprenoids could indicate a stratified water column om in a few samples with lower than average hydrogen index hi is mainly of terrestrial origin with a higher proportion of c29 steranes diterpanes and oleanoids and lower concentrations of both saturated and aromatic hopanes higher pr ph a higher c34 isohopane ratio ihr34 and a lower homohopane index hhi indicate that this low hi om was originally deposited under more oxic conditions and subsequently transported to deeper water low sterane and hopane isomerization ratios show that no samples have reached the oil window some novel maturity parameters for immature lacustrine samples are proposed

petrology mineralogy and geochemistry of the lower cretaceous oil prone coal and host rocks from the laoheishan basin northeast china abstract the coal and host rocks mainly oil shale partings in the laoheishan basin ne china are oil prone this study uses petrological mineralogical and geochemical analyses to determine the reasons of high oil yield in the coal and the origin and modes of occurrence of the minerals and elements in the coal and oil shale partings the obtained data show that this sub bituminous b coal has higher oil yield av 10 than oil shale partings av 5 7 consistent with a higher hydrogen content in the coal this oil prone coal has potential for comprehensive utilization due to the relatively high gross calorific value av 17 23 mj kg in the semi coke the maceral composition suggests that the relatively high hydrogen content in the coal is mainly caused by higher resinite content palynological analysis of coal and oil shale partings mainly proved the presence of gymnosperms and ferns revealing that the paleovegetation is dominated by lygodiacean osmundacean ground ferns and cupressaceaen taxodiaceaen canopy trees these canopy trees would have provided abundant hydrogen rich components e g resin to the paleomire all the identified sporopollen suggests a warm humid subtropical paleoclimate minerals in the coal include kaolinite quartz illite and or illite smectite chlorite feldspar calcite and traces of pyrite rutile and zircon similar to the oil shale partings most of the minerals quartz feldspar clay minerals rutile and zircon occur in layers within detrovitrinite and probably are of detrital origin pyrite and calcite are of epigenetic origin and probably derived from hydrothermal fluids compared with average chinese coal the laoheishan coal is enriched in zr nb in and sb zirconium and nb mainly occur in zircon indium is both organically and inorganically associated whereas antimony largely occurs in pyrite rey rare earth elements and yttrium distribution patterns of coals and oil shale partings are dominated by heavy rey enrichment whereas roof and floor samples are medium rey enriched the m hrey enrichment is probably caused by low temperature hydrothermal fluids the sedimentary input is the major controlling factor of geochemical patterns in coal and host rocks the source rocks are probably felsic intermediate igneous rocks from the surrounding basement as indicated by relatively high al2o3 tio2 ratios 7 38 cross plot between zr ti and nb y negative eu anomalies 0 28 0 96 the presence of k feldspar and plagioclase and lithic fragment types such as granite and andesite in the samples in addition source rocks of sediments have caused high zr and nb concentrations in the coal

oil shale and coal in intermontane basins of thailand the mae tip intermontane basin contains cenozoic oil shales in beds up to 1 m 3 3 ft thick interbedded with coal and mudstone the oil shales contain lamosite type alginite and give a maximum oil yield of 122 l mt 29 3 gal ton the beds are laterally continuous for at least 1 5 km 1 0 mi but pass into mudstones toward the basin margin the oil shales originated when peat swamps close to a steep basin margin were flooded by shallow lakes allowing algae to replace rooted vegetation this distinctive oil shale coal assemblage is known from many small intermontane basins in thailand where locally high geothermal gradients suggest potential for hydrocarbons

recovery of temperature salinity and potential density from ocean reflectivity this work explores a method to recover temperature salinity and potential density of the ocean using acoustic reflectivity data and time and space coincident expendable bathythermographs xbt the acoustically derived vertical frequency 10 hz and the xbt derived vertical frequency 10 hz impedances are summed in the time domain to form impedance profiles temperature t and salinity s are then calculated from impedance using the international thermodynamics equations of seawater gsw teos 10 and an empirical t s relation derived with neural networks and finally potential density is calculated from t and s the main difference between this method and previous inversion works done from real multichannel seismic reflection mcs data recorded in the ocean is that it inverts density and it does not consider this magnitude constant along the profile either in vertical or lateral dimension we successfully test this method on mcs data collected in the gulf of cadiz ne atlantic ocean t s and are inverted with accuracies of tsd 0 1 c ssd 0 09 and sd 0 02kg m 3 inverted temperature anomalies reveal baroclinic thermohaline fronts with intrusions the observations support a mix of thermohaline features created by both double diffusive and isopycnal stirring mechanisms our results show that reflectivity is primarily caused by thermal gradients but acoustic reflectors are not isopycnal in all domains

observations of internal solitary waves near the oregon coast with an inverted echo sounder observations of internal solitary waves isws were made near the oregon coast with a moored 200 khz inverted echo sounder ies and a 12 element vertical array of thermistors over a 14 day period during september 1995 downward pycnocline displacements conforming to the classical kortweg devries hyperbolic secant squared profile with typical amplitudes of 5 to 14 m propagation speeds of 0 4 to 0 6 m s 1 and duration of 100 to 200 s were observed with both the ies and thermistor array pycnocline displacements from 5 to 22 m depth were observed acoustically exploiting the backscatter from zooplankton layers which acted as tracers of water motions the typical volumetric scattering strength of these zooplankton layers was near 75 db referenced to 1 m 1 within the top 10 m plumes of microscopic air bubbles injected by breaking surface waves were advected downward by the isws with volumetric scattering strengths in excess of 36 db finally near surface acoustic scattering zones suspected to exhibit backscatter from turbulent microstructure were observed with typical volumetric scattering strength near 68 db these near surface zones were coincident with model predictions of large shear instabilities and local gradient richardson numbers below the critical value for generation of turbulence

observation and analysis of the tidal gravity variations at asuka station located on the antarctic ice sheet tidal gravity observations were made at asuka station 71 5 s 24 1 e antarctica the lacoste romberg model g 805 gravity meter was altered to integrate an electrostatic feedback amplifier and was installed in a snow pit records for tidal analysis were obtained from june 26 to november 13 1987 at a sampling interval of 30 min from the estimated tidal amplitudes corrections for the oceanic effects were made using schwiderski s cotidal maps the ocean tide corrected factors which define the response of the deformable earth to lunar solar tidal forces were found to be 1 169 0 008 o1 1 127 0 017 p1 1 135 0 006 k1 1 261 0 033 m2 and 1 302 0 039 s2 the diurnal factors agree with those obtained from statistically derived formulas by melchior and de becker however the semidiurnal factors m2 and s2 are 10 larger than the theoretical values predicted by wahr this is much larger than the typical 1 2 discrepancy between the statistical model and theory similar tidal gravity observations made at syowa station 69 0 s 39 6 yielded consistent results with those monitored at asuka station the observed m2 factors have a tendency to increase from the equator toward the southern high latitudes the increasing effect of inaccurate ocean load tidal corrections may be due to schwiderski s cotidal chart tidal analysis resulted in a gravity admittance of 0 24 0 04 gal mbar for the air pressure change at asuka station the smaller magnitude compared with the typical value of 0 35 gal mbar for a normal crust may be explained by the loading deformation of the ice sheet under the air mass covering an extent of 30 km over the site

markov chain monte carlo inversion of temperature and salinity structure of an internal solitary wave packet from marine seismic data marine seismic reflection technique is used to observe the strong ocean dynamic process of nonlinear internal solitary waves isws or solitons in the near surface water analysis of isws is problematical because of their transient nature and limitations of classical physical oceanography methods this work explores a markov chain monte carlo mcmc approach to recover the temperature and salinity of isw field using the seismic reflectivity data and in situ hydrographic data the mcmc approach is designed to directly sample the posterior probability distributions of temperature and salinity which are the solutions of the system under investigation the principle improvement is the capability of incorporating uncertainties in observations and prior models which then provide quantified uncertainties in the output model parameters we tested the mcmc approach on two acoustic reflectivity data sets one synthesized from a ctd cast and the other derived from multichannel seismic reflections this method finds the solutions faithfully within the significantly narrowed confidence intervals from the provided priors combined with a low frequency initial model interpreted from seismic horizons of isws the mcmc method is used to compute the finescale temperature salinity acoustic velocity and density of isw field the statistically derived results are equivalent to the conventional linearized inversion method however the former provides us the quantified uncertainties of the temperature and salinity along the whole section whilst the latter does not these results are the first time isws have been mapped with sufficient detail for further analysis of their dynamic properties

depositional environment of oil shale within the second member of permian lucaogou formation in the santanghu basin northwest china abstract the non marine santanghu basin in northwest china hosts one of the richest and thickest permian lacustrine source rock intervals in the world conventional oil in jurassic sandstone reservoirs and tight oil in the tuffaceous permian tiaohu formation were sourced from mudrocks in the underlying second member of lucaogou formation which also have tight oil potential proved by recent commercial discoveries based on inorganic and organic geochemistry organic petrography and stable isotope geochemistry the depositional environment and the tight oil potential of the second member of permian lucaogou formation were investigated the data imply a gradual evolution of the depositional environment from a stratified saline to a freshwater lake the succession can be subdivided into a lower middle and an upper unit each characterized by decreasing water salinity high bioproductivity has been caused by the bloom of algae and photosynthetic cyanobacteria water column stratification accelerated the activity of methanothrophs as indicated by low 13c values of hopanes biomarker composition provides evidence for decreasing contributions of cyanobacteria to the biomass and increasing abundance of prasinophytae compared to other algae with decreasing salinity enhanced terrigenous organic matter input appeared during periods of high freshwater inflow low total organic carbon toc contents in the lower unit are most likely caused by rapid sedimentation rate high bioproductivity and excellent preservation conditions resulted in high toc contents in the middle unit terrigenous organic matter input increased together with fresh water inflow in the upper unit resulting in high toc values during periods of possibly low sedimentation rates in a deep water column the samples of the second member exhibit a good to very good potential to generate conventional oil high toc and extractable organic matter yields together with the thickness of the fine grained sediments show that the middle and upper units of the second member of lucaogou formation hold significant tight oil potential mineralogical composition of this dolomite rich shale with respect to abundance of brittle minerals including quartz and carbonates and rare clay testifies a good tight oil potential

tidal parameters for an inelastic earth abstract the gravimetric factors for an elliptical uniformly rotating earth are computed according to a new definition with respect to wahr s results and considering the mantle inelasticity the love numbers h and k are defined in the elliptical earth case to correspond to the love spherical definition they become latitude dependent the tidal parameters discussed in this paper are computed for an inelastic earth s mantle the numerical results show an increase of 0 4 of the gravimetric factors with respect to the wahr s values the love numbers h and k increase by 1 4 to 3 with respect to the elastic case

intensive shipboard observations of the flow through the strait of gibraltar during the european project canary island azores gibraltar experiment canigo intensive shipboard observations were carried out in april 1996 and october 1997 in order to observe the spatial and temporal variability of the flow and of the water mass structure in the strait of gibraltar at the sill and the eastern and western entrances to the strait repeated cross strait sections and station time series of the flow and of t s profiles were measured using vessel mounted and lowered acoustic doppler current profilers adcp and conductivity temperature depth probes ctd expendable bathythermographs xbt yielding new views of the rapid changes over tidal cycles and of approximate tidal means it is argued that transport observations might be easier to carry out away from the sill in the eastern part of the strait even though maximum resolved shears were comparable in both places 0 03 0 04 s 1 in the vertical and 0 001 0 016 s 1 in the horizontal in the east coordinated changes in the stratification and the flow field are documented via four time series over m 2 tidal cycles showing a sharpening diffusing of the vertical gradients in the water masses and the flow maximum shear and maximum water mass gradients do not always coincide there and both are much shallower 50 80 m than the delimiter between inflow and outflow 120 150 m the mean salinity of the outflow core decreases from 38 43 in the east to 38 17 west of the sills as a result of the mixing processes the internal bore was followed and directly observed with rapid ctd yoyo stations and with xbt vessel mounted adcp measurements it generates extreme changes in currents and shears on timescales of minutes with directly measured vertical velocities reaching 50 cm s 1 patches of density inversions were observed as the bore passed by consistent with active turbulent mixing along the interface the time series of flow and ctd measurements allow the direct calculation of froude numbers at various locations and over tidal cycles these and along strait sections suggest that the exchange through the strait is maximal in april 1996 and submaximal in october 1997 supporting the expectations of garrett et al 1990

seismic observations from a yakutat eddy in the northern gulf of alaska recent works show that the seismic oceanography technique allows us to relate water column seismic reflections to oceanic finescale structures in this study finescale structures of a surface anticyclonic eddy have been unveiled by reprocessing two seismic transects acquired in the northern gulf of alaska using an 8 km hydrophone streamer and 6600 cu in linear airgun array in september 2008 the eddy was a typical bowl like structure with around 55 km width and 700 m depth it has two fringes around the eddy base and a spiral arm at the ne edge the in situ sea surface temperature and salinity data from a shipboard thermosalinograph help to confirm our interpretations of a spiral arm shed from the warm eddy and the entrained cold water from elsewhere nearby the eddy and offshore the shelf break there is a strong frontal feature probably the alaska current the eddy likely formed offshore yakutat shelf and transported along the offshore shelf break by tracking the sea level anomalies its equivalent diameter of 65 km was measured using the along track altimeter and the seismic constraints it was comparable with results from the representative conventional algorithms of eddy detection geostrophic velocities of the eddy were estimated from the dipping seismic reflections under the assumptions of approximate isopycnals and geostrophic balance measured water properties including sea surface temperature salinity and chlorophyll revealed that eddy translation transports coastal water to the pelagic regions structures synthesized from ctd profiles that sampled an earlier eddy suggest that thin striae around the base might be a common feature in gulf of alaska eddies

nonlinear internal waves in the south china sea observation of the conversion of depression internal waves to elevation internal waves 1 the conversion of depression nonlinear internal solitons to elevation internal waves has been observed twice at the south china sea continental shelf break shipboard x band radar tow yo ctd adcp and high frequency acoustic flow visualization of the process are presented the data focuses on up slope propagation of depression internal solitons from a water depth of 264 m to a water depth of 110 m dissipation by large amplitude shear instabilities was observed the kinetic energy density was found to be a decreasing monotonic function of range with an energy dissipation rate coefficient of 0 063 km 1 the rate of energy dissipation over the 16 5 km soliton propagation path was 0 17 w m m simple numerical models of the waveform evolution are qualitatively compared to the observations the observations extracted scale parameters and dissipation rates should be useful for testing a variety of evolution equation representations of internal soliton propagation

bacterial and algal hydrocarbons in sediments from a saline antarctic lake ace lake capillary gas chromatography mass spectrometry c gc ms and iatroscan thin layer chromatography flame ionisation detection tlc fid were used to study hydrocarbon distributions in a sediment core from ace lake a saline meromictic lake in the vestfold hills of antarctica hydrocarbons were abundant in most core sections up to 125 g g dry wt particularly in near surface samples and the distributions were very complex major constituents were identified as phytane 2 6 10 15 19 pentamethyleicosane tetrahydrosqualene a mixture of phytenes cholesta 3 5 diene and fern 7 ene smaller amounts of sterenes and hopenes were also present the predominance of the first 3 acyclic isoprenoids in sediments buried less than 30 cm is consistent with high populations of methanogenic bacteria known to be present phytenes were abundant in all core sections and there was no relationship between their abundance and that of phytane which suggests that they were not derived from methanogenic bacteria phytadienes were minor constituents at all depths studied an unusual feature of some distributions was the high concentrations of fern 7 ene which was the major hydrocarbon in the 20 25 cm core section this alkene was only abundant in sediments which contained high concentrations of methanogen markers suggesting that it may also be indicative of anoxic depositional environments a possible source might be from purple non sulphur bacteria high concentrations of straight chain c29 and c34 alkenes were also found in these sediments but their origin has not been determined major changes in the hydrocarbon distributions with depth indicate that the depositional environment in the lake has altered dramatically since the lake was formed less than 8000 years ago the present condition of permanent anoxic bottom waters probably developed only in the last 1000 years

submesoscale features and turbulent mixing of an oblique anticyclonic eddy in the gulf of alaska investigated by marine seismic survey data

structure and significance of c30 4 methyl steranes in lacustrine shales and oils abstract the structure of the abundant c 30 4 methyl steranes of ancient freshwater lacustrine sediments and derived oils is of interest as their precursors the 4 methyl and in particular 4 23 24 trimethyl sterols dinosterols are reported to be specific to dinoflagellates this study employs a novel liquid crystal gc phase combined with gc ms and gc ms ms to separate and characterise mixtures of c 30 4 methyl sterane standards not resolvable on non polar phases this technique is then applied to identify the c 30 4 methyl steranes in an ancient freshwater sediment a freshwater lacustrine and a marine derived oil a comparison is also made with the 4 methyl steranes in marine sediments containing varying amounts of dinoflagellate cysts the c 30 4 methyl steranes of the freshwater lacustrine samples have been shown to possess a 4 methyl 24 ethylcholestane structure while both 4 methyl 24 ethylcholestanes and 4 23 24 trimethyl 5 h cholestanes dinosteranes were found in the marine dinoflagellate rich sediments while still indicative of dinoflagellates 4 methyl 24 ethyl sterols are generally not the major dinoflagellate sterol and alternative explanations for the abundance of 4 methyl 24 ethylcholestanes in ancient lacustrine sediments should be considered possibly ancient freshwater dinoflagellates synthesised principally the 4 methyl 24 ethyl form alternatively a source from an unrecognized algal class is possible while a source from bacteria which are known to synthesise certain 4 methylsterols is discussed

direct temperature and salinity acoustic full waveform inversion 1 recent work has shown that full waveform inversion could be suitable to extract physical properties such as sound speed c density temperature t and salinity s from the weak impedance contrasts associated with the ocean s thermohaline fine structure the seismic inversion approaches proposed so far are based on the iterative inversion of c from multichannel seismic data while the rest of parameters t s and are determined in a second step using two equations of state and a local t s empirical relationship in this work we present an alternative to this approach using 1 d synthetic seismic data we demonstrate that the direct full waveform inversion of t and s using adjoint methods is feasible without the use of any local t s relationship and that the models of physical properties obtained with this approach are far more accurate than those inferred from c

elasto gravitational deformation relative gravity changes and earth dynamics summary we consider the elasto gravitational deformation of an earth model with fluid parts core ocean atmosphere a love number formalism is used in order to express the global deformation induced by volume potentials tides variations in the earth s rotation or boundary conditions in pressure transverse stress load at the interfaces between the fluid layers and the solid mantle the induced disturbances in gravity are expressed with the help of generalized gravimetric factors and special attention is paid to resonance processes various applications related to global earth dynamics are developed and numerically quantified the surface gravity changes caused either by a variation in the direction of the earth s rotational axis polar motion or in the rotation rate length of the day are compared with the lunisolar gravimetric tides the loading effect due to the oceans is found to increase the oceanless gravimetric factor by about 2 5 per cent two simplified approaches are proposed to model the gravity perturbations originating in the fluid core e g due to buoyancy core modes it is shown that a degree 2 planetary scale pressure field acting at the core mantle boundary of about 80 pa is able to induce a 10 ngal surface signal similarly gravity contributions from the atmosphere or oceans are derived using outer pressure load or spheroidal shear stress gravimetric factors a degree 2 surface pressure and transverse traction of 100 pa causes a gravity change of 0 27 and 0 14 pgal respectively finally we point out that in addition to the solar gravitational tide there are several other contributions rotational meteorological appearing in the annual gravity signal by different gravimetric factors we therefore conclude that high precision relative gravimetry can provide useful information not only about the earth s physical properties but also about its dynamical behaviour

sedimentology and geochemistry of cretaceous source rocks from the tiancao sag yin e basin north china implications for the enrichment mechanism of organic matters in small lacustrine rift basins abstract petrography and compositions of organic matters of cretaceous source rocks from the tiancao sag the yin e basin northern china have been presented in order to determine the cretaceous sedimentary environment and processes that enriched organic matters the mudstones of the bayangobi formation have medium high total organic carbon toc 0 27 2 59 and s1 s2 0 30 12 23 mg hc g rock values vertically three sedimentary units 2460 2600 m 2640 2860 m and 3020 3050 m present good hydrocarbon potentials the macerals the c27 c29 regular sterane distribution and the isotopic and element geochemistry of the kerogen prove that the organic matter has a mixed origin of plankton algae and terrestrial plants the vitrinite reflectance tmax and biomarker parameters collectively suggest that the source rocks have reached the mature stage the mudstones were deposited in a reducing brackish saline environment and the salinity sensitive proxies indicate a gradual evolution of the sedimentary conditions from low to high salinity the positive correlation between the hydrogen index value and toc content and the negative correlation between pr ph ratio and toc content suggest that the primary productivity and preservation in reducing water collectively contributed to organic matter enrichment of the bayangobi formation the relationship between sedimentation rate and toc content suggests that a sedimentation rate of 60 70 m myr is conducive to the formation of effective source rocks therefore the organic matter enrichment of bayangobi formation was controlled by moderate high paleoproductivity reducing conditions and an appropriate sedimentation rate this paper proposes a supply preservation dilution model for the source rocks in the tiaocao sag yin e basin

the marine permian of east and northeast asia an overview of biostratigraphy palaeobiogeography and palaeogeographical implications abstract the permian marine biostratigraphy faunal successions and mutual correlations where possible throughout east and northeast asia are synthesized region by region based on both published literature and the author s field observations in certain parts of the region the correlation of the permian marine successions of ne asia with the permian international timescale and in particular with gondwanan permian marine sequences remains a major challenge due to profound marine provincialism during the permian however by employing biogeographically mixed faunas from east asia se mongolia ne china south primorye of far east russia and the south kitakami terrane of japan as biostratigraphic gateways coupled with some bipolarly and bi temperately shared permian marine taxa and faunas it has been possible to correlate with reasonable confidence some of the high palaeolatitude permian marine rock units and faunas of ne asia with those of the tethyan region and gondwana palaeobiogeographically the permian marine faunas of east and ne asia are assigned to four major provinces verkolyman sino mongolian japanese cathaysian and panthalassan provinces on the basis of their palaeogeographical distribution patterns and characteristics of faunal assemblages of these the sino mongolian japanese province has considerable significance for regional palaeogeographical plate tectonic and palaeoceanographical reconstructions during the middle permian because of its conspicuously mixed cool and warm water marine biota the origin of this biogeographically mixed marine biota is interpreted to have resulted from a combination of some key factors including the increased tectonic convergence between the bureya jiamusi terrane and the sino korean platform during the permian and the intermingling of both warm and cold water ocean currents off the eastern coastal areas of the bureya jiamusi terrane and the sino korean platform during the middle permian

paleoenvironment of the eocene coal seam in the fushun basin ne china implications from petrography and organic geochemistry abstract the fushun basin in northeast china is a strike slip basin filled with coal bearing eocene sediments the basin fill includes from base to top volcaniclastic rocks a 20 to 145 m thick coal seam lower eocene guchengzi formation and lacustrine oil shale up to 300 m thick jijuntun formation the sub bituminous coal of the guchengzi formation famous for the amber inclusions is exploited in the largest opencast coal and oil shale mine in asia in the present contribution the depositional environment and the thermal history of the guchengzi formation are investigated based on macro and micropetrographic data bulk geochemical parameters biomarker analysis stable isotope geochemistry and vitrinite reflectance measurements according to our interpretation accumulation of the low sulfur coal commenced in a low lying mire near a shallow lake subsequently low ash coal was deposited either in a low lying mire protected from clastic influx or in a raised mire finally high subsidence rates typical for strike slip basins caused the flooding of the mire and terminated peat accumulation pristane phytane ratios suggest a gradual change from oxic to less oxic conditions during the drowning phase of the seam organic rich shales accumulated in the newly formed freshwater lake and resulted in the deposition of the overlying oil shale bearing jijuntun formation the coal is rich in liptinite macerals especially sporinite gymnosperms dominated the paleovegetation of the mire something that is also reflected by the frequent occurrence of resinite and amber and their biomarker composition the coal reached the sub bituminous or even the high volatile bituminous stage despite the limited burial depth simple 1d models suggest that this is a result of high heat flow rather than of deep burial and erosion the hydrogen rich coal is oil prone

observations of load tides at the south pole abstract the use of tidal observations to study the nearly diurnal free wobble mode of the earth is possible if oceanic effects in the tidal record are accurately removed we have analyzed vertical gravity data from the south pole to determine the amplitude and phase of the small daily and semidaily tides observed at the pole since these signals at the pole are most probably caused by oceanic tides our observations provide an excellent target for the oceanic models a comparison with the best models of the oceans now available indicates the need for improvement in measuring and modeling the southern oceans

review of the earth tidal models and contribution of earth tides in geodynamics the attraction of the moon and the sun on the earth induces deformations of the earth body at the surface of the earth these effects are described using tidal parameters which are observed by tidal instruments and estimated using an earth model these tidal parameters are indeed computed from a linear combination of the displacement field the stress field and the potential due to the mass readjustment associated with the tides the theoretical tidal parameter values depend crucially on the model used for the interior of the earth the system of equations used in the computation contains a stress strain relationship this equation is the only one which changes when considering mantle inelasticity instead of elasticity for an inelastic mantle the stress strain relationship is a hooke law with complex and frequency dependent rheological parameters the numerical values of these rheological parameters depend on the hypotheses formulated on the earth body even after the introduction of mantle inelasticity in the equations there are still some differences between the theory and the observations by increasing the complexity of the model scientists want to decrease the difference between the theory and the observations this comparison brings answers to very important points in geophysics in particular the resonances at the free core nutation frequency and at the free inner core nutation frequency in the tidal response give the values of these earth normal mode periods and the comparison between the observed and the computed period constrains the core flattening and the jump in the density at the inner core outer core boundary respectively

a discussion of world wide measurements of tidal gravity with respect to oceanic interactions lithosphere heterogeneities earth s flattening and inertial forces abstract by the end of 1981 the international center of earth tides icet had collected and evaluated a considerable amount of data from 180 stations including those of the trans world profile which ensure for the first time a world wide distribution including the tropical areas and the southern hemisphere in 1979 80 new oceanic cotidal maps of high quality established by schwiderski became available these maps fit on land tidal gravity measurements quite successfully a new theoretical approach developed by wahr in 1981 has resulted in a set of theoretical formulae establishing the latitude dependence of the classical elastic amplitude factors for tidal deformations we calculate here for six tidal waves the correlations between the observed gravity variations and those resulting from a calculation based upon the schwiderski maps these correlations are highly significant after subtraction of these oceanic effects we calculate the latitude dependences of the experimentally determined amplitude factors which are found to fit wahr s theoretical formulae there remains however a serious discrepancy in the constant terms of the various formulae the effects of heterogeneities in the lithosphere on tidal deformations are also clearly identified

ocean temperature and salinity inverted from combined hydrographic and seismic data recently seismic reflection methods have been successfully applied to oceanographic issues here we present a new approach combining xbt and ctd surveys with seismic observations to visualize long sections with a resolution down to a few meters the challenge to a full investigation of mixing processes has been the tremendous span of spatial scales ranging from hundreds of kilometers to centimeters traditional hydrographic observations could only resolve the large scale effects by measuring temperature and salinity profiles at discrete locations typically several kilometers apart whereas dedicated localized measurements allowed investigation of the ocean fine structure at the other end of the spatial spectrum the intermediate scales have in contrast been difficult to observe systematically here we present temperature and salinity data inverted from seismic observations that cover the intermediate scales and provide a new approach to image mesoscale processes and allow the investigation of their dynamics at unprecedented resolution

fernenes and other triterpenoid hydrocarbons in dicroidium bearing triassic mudstones and coals from south australia tandem sector mass spectrometry of the aliphatic hydrocarbon fraction of selected late triassic sub bituminous coals mudstones and plant fossils from the leigh creek coalfield telford basin south australia has revealed three pseudohomologous series of triterpenoid hydrocarbons two of these series have been identified as fern 8 enes c29 c31 and fern 9 11 enes c29 c30 the third series c29 c31 comprises saturated hydrocarbons tentatively identified as fernanes these hydrocar bons appear to be related to pteridosperms seed ferns of the genus dicroidium fronds of which are preserved throughout the sedimentary sequence 1998 elsevier science ltd all rights reserved

cyclic terpenoids of contemporary resinous plant detritus and of fossil woods ambers and coals abstract cyclic terpenoids present in the solvent extractable material of fossil woods ambers and brown coals have been analyzed the sample series chosen consisted of wood remains preserved in holocene to jurassic sediments and a set of of ambers from the philippines copalite israel canada and dominican republic the brown coals selected were from the fortuna garsdorf mine and miocene formations on fiji the fossil wood extracts contained dominant diterpenoid or sesquiterpenoid skeletons and aromatized species were present at high concentrations with a major amount of two ring aromatic compounds tricyclic diterpenoids were the predominant compounds in the ambers aromatized derivatives were the major components consisting of one or two aromatic ring species with the abietane and occasionally pimarane skeletons the saturated structures were comprised primarily of the abietane and pimarane skeletons having from three to five carbon c1 c2 etc substituents kaurane and phyllocladane isomers were present in only minor amounts bicyclic sesquiterpenoids as saturated and partial or fully aromatized forms were also common in these samples but only traces of sesterterpenoids and triterpenoid derivatives were found the brown coal extracts were composed of major amounts of one and two ring aromatized terpenoids with a greater proportion of triterpenoid derivatives than in the case of the woods and ambers this was especially noticeable for the german coal where the triterpenoids were predominant open c ring aromatized structures were also present in this coal steroid compounds were not detectable but some hopanes were found as minor components in the german brown coal an overview of the skeletal structure classes identified in each sample as well as the general mass spectrometric characteristics of the unknown compounds are included in the present paper it can be concluded from these structural distributions that aromatization is the main process for the transformation of terrestrial cyclic terpenoids during diagenesis constituting a general pathway for all terpenoids

anomalous ocean load tide signal observed in lake level variations in tierra del fuego 1 we demonstrate the application of a 100 km long lake as a sensor for studying the tidal effects on tierra del fuego main island the lake level variations observed in lago fagnano reflect both the direct response to the tidal potential and the indirect effect of the ocean tidal loading modeling both contributions explains the observed tidal signal in the lake to about 70 underestimated model load tide amplitudes are found to be probably responsible for the remaining difference we interpret this discrepancy as a hint for regional elastic lithosphere properties differing substantially from those represented by currently available global models

internal solitary waves in the warm pool of the western equatorial pacific abstract during the spring tides of late november 1992 early january and early february 1993 solitary internal wave packets were observed at 2 s 156 15 e in the western equatorial pacific apparently generated in the nuguria island group 3 s 153 e the waves propagate northeastward at 2 4 2 8 m s 1 appearing in fixed phase with the underlying semidiurnal baroclinic tide the initial solitary wave crests have downward displacements in excess of 60 m and peak velocities greater than 80 cm s 1 groups of 1 3 crests are observed with vertical structure resembling a first mode internal wave and horizontal variability consistent with third order comb kdv solitons many of the packets exhibit an overall organization reminiscent of undular bores this borelike behavior is confined primarily to the upper 70 m not sharing the mode one dependency of the crests the solitons displace the ambient equatorial currents including the equatorial undercurrent both vertically 80 m and laterally 1 2 km with l

a new data bank for tidal gravity measurements db 92 abstract tidal gravity parameters are now available in 352 permanent or temporary stations all over the world previous tentative interpretations of these data were made on the basis of a data bank created in 1980 1982 which contained all available results without any discrimination which could have appeared as arbitrary these interpretations were criticized on the basis of the different qualities of instruments null instruments or not data calibration and necessary corrections for ocean continent interactions as we agree that a careful re examination of the basic data is needed before any geophysical discussion we have built this new data bank which contains only those 211 stations where rigid control of every step in the observations calibrations and reduction could be made either because the original data are stored in the world data center c or because the published results give enough information to permit checks and revisions as a result the scattering in the tidal parameters is reduced by a factor of 2 with respect to the previous data while the mean values of the amplitude factors of the two main waves o 1 diurnal m 2 semi diurnal calculated continent by continent agree with the best available earth model it is expected that this new data bank will be used for renewed discussions of the results

maceral and geochemical characteristics of coal seam 1 and oil shale 1 in fault controlled huangxian basin china abstract seven samples of coal seam 1 and oil shale 1 from the fault controlled hangxiang basin have been analysed by coal petrographic and geochemical methods high huminite ratios and high contents of sesquiterpenoids and diterpenoids indicate that coal seam 1 and oil shale 1 are predominantly composed of terrestrial higher plant material two ternary diagrams of facies diagnostic macerals and biomarkers were used to interpret the depositional environments of organic matter in coal seam 1 and oil shale 1 in both diagrams coal seam 1 is plotted in the forest moor zone but the top sample of coal seam 1 shows an influence of transgressed sea water oil shale 1 is plotted in a transition zone from forest moor to open moor this indicates an increased abundance of lower plants and algal derived organic matter in oil shale 1 relative to coal seam 1 the boundary faults controlled the sedimentation in huangxian basin when the faults ceased to move the peat of coal seam 1 was formed when the faults became active again and the basin began to sink sea water flowed into the swamps at which time oil shale 1 was deposited

organic matter accumulation in the oil shale and coal bearing huadian basin eocene ne china abstract the huadian basin located in northeastern china is a fault controlled basin filled by eocene non marine sediments assigned to the huadian formation the formation is subdivided from bottom to top into three members pyrite member oil shale member and carbonaceous shale member using bulk geochemical data from borehole hd3 and core descriptions from a high number of wells the factors controlling organic matter accumulation have been evaluated the organic matter content of the pyrite member is relatively low average toc 0 9 wt mudstones deposited in shallow lacustrine environments contain between 1 and 2 wt toc max 6 wt and a kerogen type ii hi 400 600 mg hc g toc an arid climate prevented the accumulation of thick coal the overlying oil shale member contains 13 oil shale layers which are mined underground the oil shale member has been interpreted as a 3rd order sequence significant differences exist between oil shales deposited in different systems tracts 2 m thick coaly oil shale of low quality oil yield 3 5 wt developed in the lowstand systems tract oil shale up to 7 m thick of moderate quality oil yield 4 1 8 0 wt was deposited during the transgressive systems tract tst thinner the carbonaceous shale member representing the balanced fill to overfilled stage of basin evolution hosts economic coal seams which are occasionally accompanied by shallow lacustrine shales with abundant hydrogen rich organic matter otherwise non coal layers are typically low in organic matter average toc 0 9 wt in contrast to the huadian basin a very thick coal seam overlain by a single oil shale layer more than 100 m thick developed in the eocene fushun basin this indicates major differences in the evolution of basins with similar tectonic setting and age

guidelines for evaluating petroleum source rock using programmed pyrolysis rock eval pyrolysis is used to rapidly evaluate the petroleum generative potential and thermal maturity of rocks accurate conclusions require programs every 30 60 ft 9 18 m understanding of interpretive pitfalls and supporting data such as visual kerogen vitrinite reflectance and elemental analyses the generative potential of coals is commonly overestimated by pyrolysis and is best determined by elemental analysis and organic petrography most coals show high s2 s3 5 and low hi values 300 mg hc g toc migrated oil and mud additives which alter rock eval data can sometimes be removed by special processing for immature rocks bimodal s2 peaks and pi values over 0 2 indicate contamination pyrolysis downgrades organic poor clay rich rocks which show lower hi and higher tmax values than isolated kerogen because of adsorption of pyrolyzate on the clays tmax values for small s2 peaks 0 2 mg hc g toc are unreliable tmax is affected by maturation organic matter type contamination and the mineral matrix s3 is sensitive to inorganic and adsorbed carbon dioxide and to instrumentation problems acidification of carbonate rich samples and proper maintenance improves s3 measurement constant sample weights 100 mg are recommended below a threshold weight tmax increases by up to 10 c and other parameters decrease organic rich samples which overload the detector can be diluted with carbonate detector linearity is determined by pyrolyzing various weights of an organic rich rock

observations and linear analysis of sill generated internal tides and estuarine flow in haro strait 1 current meter records from two sets of observations 20 years apart in haro strait british columbia canada are analyzed haro strait is a deep channel separated from larger bodies of water on either side by relatively shallow sills the estuarine flow in this region is in approximate geostrophic balance and is apparently unaffected by the tidally driven spring neap cycle in vertical stratification strong baroclinic variability with an amplitude 1 m s 1 close to the amplitude of the barotropic tide is present a linear theory for internal tides in silled basins is developed using no bottom flow boundary conditions to represent sill effects by comparison with observations it is concluded that an internal tide is generated at the seaward sill and propagates inshore although local damping appears to be weak no return signal is found from the inshore sill suggesting that either dissipation is strong in that area or that the internal tide is transmitted across that sill

remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern south china sea 1 evidence for baroclinic tide origin of internal solitary waves isws in the northeastern south china sea is presented based on 116 internal wave packets observed in satellite images from 1995 to 2001 these wave packets can be divided into two types a single wave isw packet containing only one isw with without an oscillating tail and a multiple wave isw packet composed of a group of rank ordered isws all of the 22 single wave isw packets occur in the deep water zone it is suggested that the isws instead of being generated by the lee wave mechanism are developed by nonlinear steepening of the baroclinic tides which are produced by the strong tidal currents flowing over a ridge in luzon strait this suggestion is verified by an ers 2 sar image which records such an evolution process from a baroclinic tide to a single isw in its spatial domain

novel triterpene derived hydrocarbons of the arborane fernane series in sediments part ii two ring b aromatized triterpenes related to the arborane fernane series were isolated from an italian triassic black shale 4 and 7 and a french jurassic laminated bituminous limestone 7 they were identified by ms and nmr spectroscopy these compounds 25 norferna 5 7 9 triene 7 c29 and 22 25 29 30 tetranor 18 ferna 5 7 9 triene 4 c26 in the case of the italian sediment belong to a family which extends to at least c32 as shown by gc ms the presence of higher homologs and ring a methylated structures in the italian triassic shale is analogous with the hopane series which together with carbon isotopic data obtained by gas chromatography isotope ratio mass spectrometry gc irms strongly support a bacterial origin for most of these compounds this suggests that 4 and 7 may result from a yet unrecognized rearrangement of sedimentary hopenes which have subsequently undergone ring b aromatization as an alternative the c29 compound 7 could arise from c30 precursors not necessarily of bacterial origin fernenes this hypothesis would apply particularly to the case of the jurassic limestone which does not show any trace of 4 nor of compounds with an extended side chain or a methyl group on ring a related structures also bearing an isopropyl group could derive by microbiological transformations from the corresponding fernen 3 ols or isoarborinol as can be deduced from the occurrence of ring a degraded monoaromatic hydrocarbons 3 and 5

coal deposition in the noric depression eastern alps raised and low lying mires in miocene pull apart basins abstract pull apart basins often form during the late stage of continental collision provided appropriate climatic conditions these basins may contain thick coal seams two such examples are the leoben and fohnsdorf basins in austria which formed in miocene times during the post collisional stage of the alpine orogene both basins contain more than 10 m of sub bituminous coal despite similar ages tectonic settings and similar stratigraphic position of the seams within the sedimentary sequence the properties of the coals differ significantly the leoben coal is quite clean whereas fohnsdorf coal is rich in ash and sulfur petrographical and geochemical methods were applied to reconstruct the environmental factors that controlled coal properties in these basins coal formation in the leoben basin commenced in an eutrophic low lying mire this was followed by deposition of the main body of coal which formed in an ombrotrophic raised mire coal deposition was only shortly interrupted by deposition of volcanic ashes due to an acid paleo environment the volcanic material within the raised mire was altered to kaolinite thick vitrain bands representing large trees are found in the lower part of the seam only siderite is the main inorganic constituent in the main coal body lakes within the raised mire were present during late stages of peat accumulation and were filled with sapropelic coal the high ash yields of this facies are due to abundant siliceous sponges siliceous crusts and tuffogenic minerals finally high subsidence rates caused the flooding of the raised mire and sapropelic shales were deposited in the newly formed lake the iron which formed siderite in the raised mire and biogenic and abiogenic silica present in the lakes within the raised mire are derived from volcanic ashes the high ash fohnsdorf coal was formed in a low lying mire close to a brackish lake the seam geometry is controlled by the progradation of a fluvio deltaic system into the brackish lake and its subsequent drowning the roof of the seam is formed by coquinoidal limestones and sapropelic shales the brackish influence reduced the acidity of the mire which resulted in the transformation of volcanic glass into montmorillonite the low acidity also promoted high bacterial activity which together with the high sulfate content of brackish waters explains the high sulfur and pyrite content of the coal its high content of biogenic methane is probably another effect of bacterial activity low ash low sulfur coal is restricted to thin layers these might represent local raised mires which formed after the withdrawal of a fluvial system

application of acoustic full waveform inversion to retrieve high resolution temperature and salinity profiles from synthetic seismic data 1 recent works show that multichannel seismic mcs systems are able to provide detailed information on the oceans fine structure the aim of this paper is to analyze whether 1 d full waveform inversion algorithms are suitable to recover the extremely weak acoustic impedance contrasts associated to the oceans fine structure as well as their potential to image meso scale objects such as meddies we limited our analysis to synthetic noise free data in order to identify some methodological issues related to this approach under idealistic conditions e g 1 d wave propagation noise free data known source wavelet we first discuss the influence of the starting model in the context of the multi scale strategy that we have implemented then we show that it is possible to retrieve not only sound speed but also salinity and temperature contrasts within reasonable bounds from the seismic data using neural network relationships trained with regional oceanographic data sets potentially the vertical resolution of the obtained models which depends on the maximum frequency inverted is of the order of 5 10 m whereas the root mean square error of the inverted properties is shown to be 0 5 m s for sound speed 0 1 c for temperature and 0 06 for salinity to conclude this study we have inverted synthetic data simulated along an oceanographic transect acquired during the eu funded geophysical oceanography go project the results demonstrate the applicability of the method for synthetic data as well as its potential to define oceanographic features along 2 d transects at full ocean depth with excellent lateral resolution

evolution of lacustrine systems along the miocene mur murz fault system eastern alps austria and implications on source rocks in pull apart basins tectonically controlled lakes developed during miocene lateral extrusion of the eastern alps mineralogy and the inorganic and organic geochemistry of rocks from three boreholes were investigated to reconstruct the evolution of lake ingering and lake groisenbach and to study the distribution of source rocks in pull apart basins gas prone coal and oil prone sapropelic shale accumulated during the initial shallow stages of lake ingering thereafter the lake deepened rapidly 125 m thick prodelta shale containing a type ii kerogen was deposited in the brackish several hundred meter deep hydrologically closed lake afterwards decreasing subsidence allowed the filling of the lake by prograding deltas during the advance of the deltaic systems the lake became shallower hydrologically open and the brackish influence terminated source rock quality decreased significantly during the filling stage of the lake a consequence of dilution of autochthonous organic matter and of enhanced input of land plants despite its considerable dimensions formation and filling of lake ingering lasted only two million years lake groisenbach was considerably smaller and more susceptible to high frequency changes in lake chemistry although the water body was temporarily oligosaline brackish conditions did not occur high sulphur contents were due to anoxic events and the inflow of ca rich waters abundant dissolved silica favoured diatoms blooms

a locally generated high mode nonlinear internal wave detected on the shelf of the northern south china sea from marine seismic observations in this work a secondary nonlinear internal wave niw on the continental shelf of the northern south china sea is investigated using high resolution seismic imaging and joint inversion of water structure properties combined with in situ hydrographic observations it is an extraordinary wave combination with two mode 2 niws and one elevated niw occurring within a short distance of 2 km the most energetic part of the niw could be regarded as a mode 2 niw in the upper layer between 40 and 120 m depth the vertical particle velocity of approximate to 41 cm s may exceed the critical value of wave breaking and thus collapse the strong stratification followed by a series of processes including internal wave breaking overturning kelvin helmholtz instability stratification splitting and eventual restratification among these processes the shear induced kelvin helmholtz instability is directly imaged using the seismic method for the first time the stratification splitting and restratification show that the unstable stage lasts only for a few hours and spans several kilometers it is a new observation that the elevated niw could be generated in a deepwater region as deep as approximate to 370 m different from the periodical niws originating from the luzon strait this secondary niw is most likely generated locally at the continental shelf break during ebb tide

deposition of coal and oil shale in ne china the eocene huadian basin compared to the coeval fushun basin abstract the huadian and fushun basins located along the dunmi fault zone ne china are filled with non marine coal and oil shale bearing sediments of eocene age despite similar tectonic setting the habitat of coal and oil shale differs significantly during this study the depositional environment of organic rich sediments in the huadian basin and factors controlling differences between both basins were investigated early in the history of the huadian basin thin coaly and bituminous mudstones accumulated in shallow lake environments pyrite member water depth increased during deposition of the oil shale member but did not exceed a few tens of meters preventing stable water column stratification moreover deposition of fan delta sediments interrupted accumulation of fine grained rocks nevertheless algal blooms and oxygen depleted conditions resulted in accumulation of 13 thin high subsidence rates in the fushun basin favored deposition of thick coal during the transgressive stage and of oil shale in a deep lake in contrast minor subsidence in the huadian basin resulted in a lake with moderate water depth and deposition of several oil shale layers with varying quality in this basin economic coal developed only during the regressive stage

polar aromatic biomarkers in the miocene maritza east lignite bulgaria aromatic and polar compounds of lignite lithotype bitumens maritza east were analyzed diterpenoid phenols and ketophenols i e mainly ferruginol sugiol hinokione and products of their diagenetic transformations were identified as the dominant biomarkers a variety of sesquiterpenoids was present as well these compounds provided evidence for the assumption that members of the cupressaceae s 1 are the coal precursors polar triterpenoids i e lupeol lupenone adiantone and hopanones were present in subordinate quantities in the humoclarain sample these biomarkers support an input of deciduous angiosperm vegetation to the peat swamp source matter three diagenetic transformation schemes for the diterpenoid phenols ketophenols are proposed 1 ferruginol and or sugiol alteration through dehydrogenation demethylation and ring b cleavage 2 hinokione aromatization to simonellite and 3 7 ketototarol change through 7 ketototar 5 enol to 20 nor 3 oxo totara 5 10 6 dienol the identified diterpenoids demonstrated the presence of gymnospermae in the coal forming community furthermore the phenolic diterpenoids indicated a specific input of organic matter from conifers of the cupressaceae taxodiaceae or podocarpaceae as the most abundant trees in the coal forming swamp

european tidal gravity an improved agreement between observations and models tidal gravity observations were made at 5 sites in europe using improved lacoste and romberg et gravimeters special attention was paid to improving the accuracy of determining both the amplitude and phase in tidal gravity measurements the measuring screws of the gravimeters were calibrated on the well established short range vertical gravity calibration lines at hannover frg for m sub 2 and o sub 1 it is shown that there is a very significant improvement in the agreement between observations and models compared to previous european tidal gravity measurements for o sub 1 the ocean tide loading and attraction is very small in europe and these observations verify that the dehant wahr anelastic body tide gravimetric factor is accurate to within 0 2 there is no dependence upon lateral changes of earth structure at least within the accuracy of these measurements

marine seismic observation of internal solitary wave packets in the northeast south china sea recently the novel seismic oceanography method has been reported to be an effective way to study the energetic internal solitary waves isws in the northern south china sea an optimized seismic oceanographic cruise was carried out to observe such near surface isws on dongsha plateau in july 2014 several soliton trains rather than single solitons were captured using the seismic technique after seismic data processing one prototypical rank ordered isw packet on northeast side of dongsha island was clearly identified for further analysis this included waveforms propagation velocities and vertical velocities for individual solitons in this study an improved scheme was applied to derive the transient phase velocities from the seismic data which is verified from independent satellite and hydrographic data analytical predictions from korteweg de vries equation fit better than the extended korteweg de vries equation ignoring background currents our results show that the seismic method can be successfully used to image targets in shallow water below 40 m and that seismic oceanography is a promising technique for studying near surface phenomena with high spatial resolution

the effect of sea tides on gravity tidal observations on the antarctic ekstrom ice shelf summary simultaneous time series of gravity variations on an ice shelf and sea level fluctuations in the antarctic have been analysed the gravity data was recorded in the observatory of the georg von neumayer gvn station on the ekstrom ice shelf in the antarctic by an askania gs 15 earth tide gravity meter an aanderaa pressure recorder was used on a mooring 10 km north of the ice shelf edge in a water depth of 468 m to measure the sea level fluctuations both time series are approximately one year in length amplitudes and phases for the tidal waves and residual spectra with minimum leakage effects were obtained using the least squares method of the hycon program the gravity variations on the ice shelf are primarily caused by the local sea tides the amplitude of the main tidal wave m2 is 80 3 gal 1 gal 10 8 ms 2 after removing the effect of the body and load tide the residual signal of 89 7 gal amplitude corresponds to a tidal height of 33 cm while the tidal acceleration is only 8 3 gal the vertical movement of the ice shelf is modelled by a simple elastic model the ice shelf is taken as a uniform elastic beam floating on the sea and clamped on one side this model constrains the location of the hinge zone of the ekstrom ice shelf to be about 55 km south of the gvn station and verifies the observed vertical displacements at this station

on the generation and evolution of nonlinear internal waves in the south china sea the nonhydrostatic regional ocean modeling system is applied to the nonlinear internal waves or solitons that are generated at the luzon ridge in the south china sea the luzon ridge near the batan islands is represented by an idealized ridge with a height of 2 6 km on a flat bottom model runs are performed for various ridge shapes and a symmetric tidal forcings the model is in the mixed tidal lee wave regime the barotropic tide over the ridge generates first mode waves through the internal tide release mechanism westward traveling solitons emerge from these first mode waves through nonlinear steepening in the internal tide release mechanism asymmetric tides with strong eastward currents can generate strong westward solitons the eastward current creates an elevation wave with a higher energy density west of the ridge and as soon as the current slackens the wave is released westward on its backslope strong solitons develop the energy density is further enhanced by nonlinearities such as differences in phase speeds and energy fluxes related to lee waves a modal and harmonic decomposition shows the generation of vertical modes and higher temporal harmonics and indicates significant wave wave interaction e g triads in the mixed tidal lee wave regime more energy is contained in the first mode compared to the higher modes hence linear internal tide beams are less well defined and strong solitons develop

tidal loading along a profile europe east africa south asia australia and the pacific ocean abstract a knowledge of the vertical component of the oceanic tidal load to a precision of at least one microgal is essential for the geophysical exploitation of the high precision absolute and differential gravity measurements which are being made at ground level and in deep boreholes on the other hand the ocean load and attraction signal contained in earth tide gravity measurements can be extracted with a precision which is sufficient to characterize the behaviour of the oceanic tides in different basins and this provides a check of the validity of the presently proposed cotidal maps the tidal gravity profiles made since 1971 from europe to polynesia through east africa asia and australia with correctly intercalibrated gravimeters comprise information from 91 tidal gravity stations which is used in this paper with this goal in mind a discussion of all possible sources of error is presented which shows that at the level of 0 5 gal the observed effects cannot be ascribed to computational or instrumental errors cotidal maps which generate computed loads in agreement with the earth tide gravity measurements over a sufficiently broad area can be used with confidence as a working standard to apply tidal corrections to high precision measurements made by using new techniques in geodesy geophysics and geodynamics satellite altimetry very long baseline interferometry moon and satellite laser ranging and absolute gravity the recent cotidal maps calculated by schwiderski for satellite altimetry reductions agree very well with land based gravimeter observations of the diurnal components of the tides o1 k1 and p1 waves but his semi diurnal component maps m2 s2 and n2 waves strangely appear less satisfactory in some large areas the maps of hendershott and parke give good results in several large areas but not everywhere more detailed investigations are needed not only for several coastal stations but mainly in the himalayas

thermohaline fine structure in an oceanographic front from seismic reflection profiling we present acoustic images of oceanic thermohaline structure created from marine seismic reflection profiles across the major oceanographic front between the labrador current and the north atlantic current the images show that distinct water masses can be mapped and their internal structure imaged using low frequency acoustic reflections from sound speed contrasts at interfaces across which temperature changes the warm cold front is characterized by east dipping reflections generated by thermohaline intrusions in the uppermost 1000 meters of the ocean our results imply that marine seismic reflection techniques can provide excellent spatial resolution of important oceanic phenomena including thermohaline intrusions internal waves and eddies

relations of petrographical and geochemical parameters in the middle miocene lavanttal lignite austria abstract samples from two lignite seams lower seam upper seam of the lavanttal basin austria and additional xylite were investigated for variations in maceral composition petrography based facies indicators bulk geochemical parameters and molecular composition of hydrocarbons both seams originated in a topogenous mire and evolved within a transgressive setting the final drowning of the mire is indicated by sapropelic shales whereas the sapropelic shale overlying the lower seam was deposited in a freshwater lake the sapropelic shale above the upper seam represents a brackish lake numerous relationships are found between petrography based facies indicators and the geochemical composition of organic matter the contents of macerals of the liptinite group are positively correlated with soluble organic matter som yields and hydrogen index hi consistent with maceral composition and high hi values enhanced proportions of short chain n alkanes which are predominantly found in algae and microorganisms are obtained from samples of the sapropelic shales the final drowning of the mire is reflected by decreasing pristane phytane ratios due to the rise in ground water table and the establishment of anaerobic conditions as well as by decreasing ratios of diasterenes sterenes indicating increasing ph values in the mire the degree of gelification of plant tissue gelification index is governed by the microbial activity in the mire as indicated by the hopanes concentration the differences in floral assemblage during the formation of the lavanttal lignite seams are reflected by major differences in tissue preservation preservation of plant tissue tpi in the lavanttal lignite is obviously controlled by the presence absence of decay resistant gymnosperms in the peat forming vegetation and additionally influenced by the relative contribution of wood to coal formation the results provide evidence that valuable information for coal facies characterization could be obtained by petrography based and geochemical facies indicators an influence of the floral assemblage gymnosperms angiosperms ratio and of the contribution of algal biomass on carbon isotopic composition of the organic matter 13c 24 2 to 28 6 is proposed carbon cycling during biogeochemical decomposition of plant tissue by bacteria is suggested to affect the 13c values of the coal the chemotaxonomical classification of the xylites as gymnosperm remnants based on the molecular composition of terpenoid biomarkers is corroborated by the carbon isotopic composition of the xylites mean 13c 24 1 and the extracted cellulose mean 13c 20 2 the higher isotopic difference of about 3 9 between cellulose and total organic carbon of the xylites compared to the difference between cellulose and wood found in modern trees is explained by the smaller effect of decomposition on 13c of cellulose

depositional environment of oil shale within the eocene jijuntun formation in the fushun basin ne china abstract the non marine fushun basin in ne china is a fault controlled basin filled with eocene sediments it hosts the largest opencast coal and oil shale mine in asia a single thick oil shale layer overlying sub bituminous coal occurs within the middle eocene jijuntun formation based on mineralogy inorganic and organic geochemistry organic petrography stable isotope geochemistry and vitrinite reflectance measurements the depositional environment and the oil shale potential of the oil shale bearing succession were investigated the jijuntun formation is subdivided into a lower and an upper unit characterized by a low and high quality oil shale respectively the thick oil shale layer of the jijuntun formation developed under long lasting stable conditions in a deep freshwater lake after drowning of a swamp the organic matter in the lower unit is characterized by landplant derived macerals the sediments containing a type ii kerogen hi 400 mghc gtoc were deposited during warm and humid conditions lacustrine organisms predominant in the upper unit are forming kerogen type i hi 700 mghc gtoc high bioproductivity and excellent preservation conditions resulted in high toc contents up to 23 6 wt in the upper unit the organic matter preservation was controlled by photic zone anoxia originating in a temperature stratified water column in the deep lake without significant changes in bottom water salinity mid eocene cooling during deposition of the upper unit of the jijuntun formation is reflected by clay mineral composition a hot and arid climate favoring brackish conditions in a shallow lake prevailed during accumulation of the overlying carbonate rich xilutian formation individual geochemical parameters in the fushun basin have to be used with caution e g the maturity proxy tmax is affected by kerogen type the redox proxy pr ph ratio is probably biased by different sources of isoprenoids this demonstrates the importance of multi proxy studies

estimating movement of reflectors in the water column using seismic oceanography the observation of spatial and temporal dynamics of the ocean is fundamental to understand global and regional aspects of water mixing physical oceanography has traditionally observed ocean structures with in situ measurements often limited in temporal and or spatial resolution in exploration seismology a set of techniques has been developed over the last decades to image and characterize the physical properties of sub seafloor structures by inversion methods at high horizontal resolution the two different fields have made contact in seismic oceanography where the well developed methods of marine reflection seismology have been applied to the dynamic ocean however one aspect so far ignored in seismic oceanography is the dynamical temporally varying nature of water structures here we show that it is possible to estimate temporal variations of reflectors in water structures as an inversion parameter the new dynamic property reflector movement velocity gives an additional parameter to characterize ocean water dynamics

inversion of density in the ocean from seismic reflection data vertical stability of the fluid particles mixing and mesoscale motions in the ocean interior occur mostly along isopycnals surfaces therefore potential density profiles with high lateral resolution would provide important information about the fluid dynamic and the general circulation in the ocean could we observe density changes from seismic data is seismic oceanography able to measure density with enough accuracy how is the relation between seismic reflectors and isopycnals surfaces we have inverted oceanic impedance from seismic data and then derived density and potential density surfaces from the oceanic impedance results of the inverted potential density have been compared with digitized seismic reflectors to show the relation between isopycnals and reflectors we have also compare the seismic profiles of the go survey with the space coincident ctds and space and time coincident xbts to understand the nature of the reflectivity and its relation with the physical parameters of the ocean

biomarker evidence for botryococcus and a methane cycle in the eocene huadian oil shale ne china the saturated and unsaturated hydrocarbons of two samples hd 19 and hd 21 from the same section of the middle eocene lacustrine huadian oil shale in ne china were identified and shown to be mainly from algal and bacterial sources comparison of the two samples provided an opportunity to explore the contribution from telalginite to the hydrocarbon profiles cells identified from microscopy as botryococcus in the telalginite of hd 21 were confirmed as belonging to the l race of b braunii from the presence of monoaromatic lycopane derivatives and small amounts of several lycopadienes lycopane was abundant and was probably derived from biohydrogenation of lycopadienes and related lipids on the basis of d 13 c values hopane distributions showed a dominance of those with the biological 17b 21b stereochemistry as expected for an immature shale with low amounts of 17b 21a hopanes moretanes and 17a 21bhopanes two hopenes were also abundant and assigned as c29 and c30 neohop 13 18 enes which occurred together with the c29 and c30 hop 17 21 enes these had depleted carbon isotope values 43 7 to 50 8 indicative of production by methane oxidizing bacteria methanotrophs the high proportion of hopanoids with carbon numbers c32 indicates extensive post depositional diagenetic alteration of bacteriohopanepolyols as well as a direct input of c30 hopanoids the data clearly indicate that there was active utilization of methane in this lacustrine depositional setting but isoprenoid hydrocarbon biomarkers for methanogens such as pentamethylicosane pmi and squalane were in surprisingly low abundance it is possible that these bacterial contributions were present as polar lipids the origins of an unusual c38 isoprenoid alkane assigned as bipristane are uncertain but may be from methanogens steranes and sterenes were relatively minor components but abundant diasterenes and 4 methyldiasterenes were present reflecting significant conversion of the original lipid composition by way of clay catalysed diagenesis the biomarker data suggest that the bottom waters in the original depositional environment had low o2 content but the sediments were probably neither sulfidic nor strongly reducing the high content of organic matter in the shale likely reflects both high but fluctuating productivity due to eutrophic conditions in the overlying water and good preservation in the sediments

some results of heterogeneous data inversions for oceanic tides many different instruments directly or indirectly observe the oceanic tidal movements among them we consider here the coastal tide gauge and deep sea pressure recorder which provide at least the principal spectral constituents of the tidal height the gravimeter which indirectly observes the oceanic tides through the gravitational effect generated by the deformation of the solid earth under the ocean tidal mass load and the satellite altimeter which samples the tides in the time domain and over the nearly whole ocean our present paper deals with an empirical method for the recovery of the oceanic tides by inversion of heterogeneous data sets the aim is to take advantage of the different kinds of information coming from the measurement instruments in order to complete more accurate empirical solutions first tide gauge and gravity loading data are separately and jointly inverted to provide global charts of the major semidiurnal m2 wave the results prove that the tide gauge data have a major contribution in the tidal mapping but also suggest that the gravity loading data distort the information this is certainly due to unmodelled geophysical phenomena and instrumental errors second tide gauge and satellite altimeter data are considered in a separate and a joint inversion computation to provide tidal estimations along a predefined geographical line in the north atlantic the results are accurate enough to make provision for the boundary conditions of an hydrodynamical tidal model as an intrinsic advantage of the inversion method a posteriori standard deviations and error covariances for all the solutions displayed are provided and analyzed

evidence for tides in the subglacial lake vostok antarctica the phenomenon of lake tides is investigated for the subglacial lake vostok east antarctica a model computation of equilibrium lake tides leads to a maximum lake level variation of about 18mm to verify the hypothesis of really existing lake tides data from two different observational techniques are analysed the re evaluation of old tidal gravity data from vostok station as well as satellite synthetic aperture radar interferometry insar reveal specific signals which are explained as lake tides the results of gravimetric tidal observations at vostok station from 1969 schneider 1971 schneider and simon 1974 show systematic deviations from the expected solid earth tide signal which correspond to a vertical tidal displacement of 12 and 2 mm amplitude for the waves k1 and m2 respectively the insar data show the areal pattern of a vertical motion at the southern lake tip which is analogous to the grounding zone of ice shelves

statistical and dynamical analyses of generation mechanisms of solitary internal waves in the northern south china sea 1 this study analyzes the effects of thermocline shoaling on the ocean internal wave iw generation in the north south china sea nscs seven years of satellite synthetic aperture radar sar images from 1995 to 2001 are used for the statistical analysis of iw occurrence and field measurements of sea surface wind sea state and vertical temperature profiles are used for analyzing iw generation and sar imaging conditions latitudinal distribution of iw packets shows that 22 of iw packets distributed in the east of 118e obviously originate from the luzon strait and 78 of iw packets west of 118e may propagate from the east or evolve into the solitons originating from the east boundary owing to the fission effect of shoaling thermocline the yearly distribution of iw occurrence frequencies reveals an interannual variability implying that there are long term and large scale processes modifying the sar observed iw occurrence the monthly sar observed iwoccurrence frequencies show that the high frequencies are distributed from april to july and reach a peak in june with a maximum frequency of 20 the low occurrence frequencies are distributed in winter from december to february of next year with a minimum frequency of 1 5 in february this study proposes that the iw generation needs the necessary and sufficient conditions initial disturbance formation and wave amplitude growth owing to the dissipation effect on the initial disturbance only fully grown waves have a chance to radiate out of the source region a physical model and pkdvequation are adopted for analyzing the sufficient conditions for solitary iw amplitude growth the results indicate that the thermocline shoaling provides the forcing to soliton amplitude growth so that the soliton amplitude growth ratio sagr serves as a decisive factor for the iw occurrence frequency theoretical analysis predicts a linear relation between the two application of theoretical models to field measurements in the luzon strait gives a correlation coefficient as high as 0 845 with a confidence level of 99 for months from march to november the linear regression gives a correlation coefficient r 2 of 0 6519 and a sagr threshold minimum value of

depositional environment of the lower cretaceous muling formation of the laoheishan basin ne china implications from geochemical and petrological analyses abstract the laoheishan basin located in northeastern china is filled with non marine coal and oil shale oil prone mudstone sediments of the lower cretaceous muling formation based on petrological mineralogical and geochemical methods the depositional environment during organic matter om accumulation is investigated for the first time the coal is subbituminous in rank petrological and bulk geochemical data indicate sapropelic coal deposited in low lying mire under freshwater conditions high pristane phytane ratios provide evidence for a land plant origin of om and oxic conditions during deposition a neutral to slightly alkaline ph is reflected by the presence of carbonate high liptinite contents and terpenoid biomarker composition indicate high amounts of resinous om during oil shale deposition a raised water table was favorable for om preservation under oxic to dysoxic conditions the oil shales in the lower unit of the succession not associated with coal are characterized by high hydrogen index and resinite contents interpreted to reflect deposition at elevated water depths in contrast to the findings of previous studies on oil shales in china indicating its origin from algal om a predominance of terrigenous om rich in waxy and resinous lipids is implied from biomarker and maceral composition the lower cretaceous oil shale and coal in the laoheishan basin contain high amounts of land plant derived terpenoid biomarkers derived from coniferales e g pinaceae cupressaceae taxodiaceae araucariaceae podocarpaceae and ferns the results are in agreement with palynological data the data highlight the potential of resinous and waxy om to form excellent hydrocarbon source rocks

relative contribution of temperature and salinity to ocean acoustic reflectivity 1 marine seismic data display laterally coherent reflectivity from the water column that is attributed to fine scale oceanic layering the amplitude of the different reflections is the expression of acoustic impedance contrasts between neighbouring water masses and therefore water reflectivity maps the ocean s vertical sound speed and density i e temperature and salinity variations here we determine the relative contribution of each parameter by computing the temperature and salinity partial derivatives of sound speed and density and using them to estimate reflection coefficients from a real oceanographic dataset the results show that the mean contribution of density variations is 5 10 while 90 95 is due to sound speed variations on average 80 of reflectivity comes from temperature contrasts salinity contribution averages 20 but it is highly variable and reaches up to 40 in regions prone to diffusive convection such as the top of the mediterranean undercurrent in the gulf of cadiz

observation of 18 6 year modulation tide at the south pole we have observed long period variations in the amplitudes of the diurnal and semidiurnal gravity tides at the south pole which we attribute to the tidal effects of the 18 6 year regression of the nodes of the lunar orbit the observations are in agreement with theoretical values of the 18 6 year amplitude modulation of these tides

full waveform inversion of reflection seismic data for ocean temperature profiles 1 we show that ocean temperature profiles can be accurately recovered using only acoustic methods employed at the sea surface using a towed air gun array and a hydrophone streamer thermohaline boundaries are ensonified at a suite of frequencies and angles yielding travel time trajectories and reflectivities these data are inverted via full waveform inversion to estimate sound speed and subsequently a temperature profile the high lateral data density of the seismic technique offers the potential of acoustically derived temperature profiles to be used to constrain models of ocean mixing and internal waves results on realistic synthetic data show that sound speed can be recovered with arbitrary accuracy when using broadband data with known source function and recording geometry application to field seismic data corroborated by expendable bathythermograph shows that even with a seismic acquisition system not specifically calibrated for seismic oceanography temperature contrasts within the ocean can be recovered to within one degree celsius

the phase lag of earth tides and the braking of the earth s rotation abstract a discussion of tidal gravity measurements performed at 292 points world wide gives after correction for oceanic effects a solid earth tide phase lag of 0 38 in fair agreement with the phase lag 0 44 estimated by schwiderski on the basis of the deceleration of the moon along its orbit this phase lag is attributed not to viscous properties of the earth but to the pressure of oceanic tides on the tidally deformed bottom of the ocean

the effects of mantle anelasticity on nutations earth tides and tidal variations in rotation rate summary we model the effects of mantle anelasticity on luni solar nutations on tidal deformation on tidal variations in rotation rate and on the eigenfrequency of the free core nutation our results can be used to invert observations to solve for the anelastic contributions to the shear and bulk moduli of the upper and lower mantle we use specific anelastic models to numerically estimate the effects of anelasticity on these geodetic observables we compare our nutation estimates with observational results among our conclusions 1 mantle anelasticity is likely to be the most important source of damping for the free core nutation 2 present vlbi nutation results are in principle accurate enough to usefully bound anelasticity at diurnal periods but the discrepancy between the vlbi observed nutations and the 1984 iau nutation model cannot be explained by anelasticity and is not yet well enough understood to allow anelasticity to be determined from the data

sesqui and diterpenoid biomarkers preserved in taxodium rich oligocene oxbow lake clays weisselster basin germany several diterpenoids of the abietane pimarane and phyllocladane type and three cadalanetype sesquiterpenoids have been identified in the organic solvent extracts of lower oligocene clay sediments haselbach strata saxony germany the sediment contains needles and cone scales of a fossil taxodium species which represents the only conifer in the samples a clear correlation between the observed conifer biomarkers and taxodium is evident apart from diterpenoids detected previously in other sediments a new diaromatic totarane diterpenoid is reported in isolated fossil and recent taxodium needles and cone scales as well as in the haselbach clays a phenolic diterpenoid of the abietane type ferruginol has been identified the results indicate that the taxodium rich clay samples contain several diterpenoids which so far have been used as biomarkers for other conifer families and thus the chemotaxonomical use of diterpenoid biomarkers for the differentiation of fossil conifer families has to be revised

the hulan group its role in the evolution of the central asian orogenic belt of ne china the hulan group of central jilin province northeastern ne china consists of felsic volcanic and sedimentary rocks that underwent sub greenschist to amphibolite facies metamorphism and multiple phases of deformation during formation of the central asian orogenic belt young nd model ages of 1100 ma obtained in this study do not support earlier models that the hulan group was either rifted from the north china craton to the south or from the jiamusi block to the north since both these blocks have much older nd model ages detrital zircon u pb ages from a meta sedimentary rock of the hulan group define a maximum age of deposition of 287 6 ma not early palaeozoic as previously believed rb sr mineral isochron data indicate that metamorphism of the hulan group occurred at 250 ma this conclusion is further supported by an age of 248 4 ma for the dayushan granite which intruded the hulan group these new isotopic data together with evaluation of the regional geology indicate that final oceanic closure in the chinese segment of the central asian orogenic belt took place in the late permian the hulan area is located along the solonker xra moronchangchun suture that extends from inner mongolia across to central jilin province it is this zone that marks the final ocean closure resulting in the amalgamation of the north china and siberian cratons 2007 elsevier ltd all rights reserved

calibrated seismic imaging of eddy dominated warm water transport across the bellingshausen sea southern ocean seismic reflection images of thermohaline circulation from the bellingshausen sea adjacent to the west antarctica peninsula were acquired during february 2015 this survey shows that bright reflectivity occurs throughout the upper 300 m by calibrating these seismic images with coeval hydrographic measurements intrusion of warm water features onto the continental shelf at marguerite and belgica troughs is identified and characterized these features have distinctive lens shaped patterns of reflectivity with lengths of 0 75 11 00 km and thicknesses of 100 150 m suggesting that they are small mesoscale to submesoscale eddies abundant eddies are observed along a transect that crosses belgica trough near alexander island drift a large of order urn x wiley 21699275 media jgrc22803 jgrc22803 math 0001 km3 bowl like feature that may represent an anticyclonic taylor column is imaged on a pair of orthogonal images a modified iterative procedure is used to convert seismic imagery into maps of temperature that enable the number and size of eddies being transported onto the shelf to be quantified finally analysis of prestack shot records suggests that these eddies are advecting southward at speeds of urn x wiley 21699275 media jgrc22803 jgrc22803 math 0002 m s 1 consistent with limited legacy hydrographic measurements concentration of observed eddies south of the southern antarctic circumpolar current front implies they represent both a dominant and a long lived mechanism of warm water transport especially across belgica trough our observations suggest that previous estimates of eddy frequency may have been underestimated by up to 1 order of magnitude which has significant implications for calculations of ice mass loss on the shelf of the west antarctic peninsula

isomerisation rearrangement and aromatisation of steroids in distinguishing early stages of diagenesis abstract the distributions of proposed reactants and products of stages of early diagenesis of steroid hydrocarbons have been studied by gc and gc ms in a variety of downhole sequences of dsdp cores of various ages which include the san miguel gap walvis ridge gulf of california and falkland plateau the compounds comprise aliphatic and aromatic hydrocarbons such as diasterenes monoaromatic anthrasteroids and spirosterenes from the study of the progress of proposed reactions and of presumed product reactant relationships a pattern emerges that extractable lipid distributions can provide a means of distinguishing levels of early diagenesis which cannot be recognised readily from other methods a number of diagentic trends are evident such as progressive isomerisation at c 20 in diasterenes which occurs at different relative rates and temperature ranges in sediment sequences with different heat fluxes such studies allow investigation of the changes in biological marker compounds in the part of the continuum between changes during sediment deposition and the advent of catagenesis

absolute reflection coefficients from deep seismic reflections abstract many deep seismic reflection profiles show bright sub horizontal layered reflections in the lower continental crust accurate estimates are obtained for normal incidence reflection coefficients for the brightest of these reflections by using a marine seismic acquisition system that has been calibrated using deep water sea bottom multiples minimum bounds are placed upon these reflection coefficients by assuming minimum losses due to scattering anelastic attenuation and geometric spreading reflection coefficients of around 0 1 are obtained from the layered lower crust and around 0 15 from the moho it is argued that constructive interference between successive reflections from a layered sequence of reflectors is often unimportant consequently these coefficients can be used to place useful limits on the absolute acoustic impedance contrasts present at depth

large amplitude internal solitary waves observed in the northern south china sea properties and energetics abstractfive large amplitude internal solitary waves isws propagating westward on the upper continental slope in the northern south china sea were observed in may june 2011 with nearly full depth measurements of velocity temperature salinity and density as they shoaled at least three waves reached the convective breaking limit along wave current velocity exceeded the wave propagation speed c vertical overturns of 100 m were observed within the wave cores estimated turbulent kinetic energy was up to 1 5 10 4 w kg 1 in the cores and at the pycnocline the gradient richardson number was mostly 0 25 the maximum isw vertical displacement was 173 m 38 of the water depth the normalized maximum vertical displacement was 0 4 for three convective breaking isws in agreement with laboratory results for shoaling isws observed isws had greater available potential energy ape than kinetic energy ke for one of the largest observed isws the total wave energy per unit meter along the wave crest e