recent current observations in the eastern yellow sea observations of current velocity pressure and temperature in the eastern yellow sea from january 10 through april 12 1986 together with geostrophic winds calculated from surface atmospheric pressure distributions are analyzed for a study of the synoptic band response of the yellow sea to the wintertime winds north wind pulses in the winter monsoon are found to give rise to northward flow bursts in the yellow sea trough which appear to peak just as the wind relaxes and to be driven by a synoptic band north to south rise in bottom pressure synchronous with the north wind pulses the existence of a similar rise in coastal sea level indicates that the observed southward pressure rise is but an offshore extension of a setup along the west coast of south korea forced by the north wind pulses the advection by northward flow bursts of warm water from the south apparently causes the measured temperature to be substantially higher in the trough than in coastal waters at the same latitude and the observed rate of cooling in the trough to be less than half of that in coastal waters to the east a winter to spring transition is also found in the bottom pressure records obtained in the trough in which the mean north to south gradient in winter reverses suddenly in early march a similar reversal also appears in sea level records along the west coast of south korea the reversal appears to be triggered by the weakening of the north winds at the arrival of spring

a diagnostic model of summer circulation on the northwest shelf of the east china sea abstract hydrographic data and moored current meter records collected during a cruise of the china u s joint study in august 1981 were used to compute the circulation in the east china sea a steady state linear diagnostic model with a constant vertical eddy viscosity was developed lateral friction was ignored the taiwan warm current plays a dominant role in the survey area both the huanghai warm current and the cyclonic cold water gyre southwest of cheju island are closely related to the taiwan warm current

wave dispersion study for tsunami propagation in the sea of marmara in this paper the aim is to investigate whether there are differences between the dispersion and non dispersion solutions on tsunami propagation for this purpose two numerical models of tsunami propagation are compared one of these numerical models is a nondispersive model that uses saint venant equations and the other is a dispersive model that uses boussinesq equations the tsunamis resulting from a submarine mass failure smf which is settled at the bottom of the north eastern sea of marmara are examined an analytical solution considering wave dispersion is developed for obtaining near field tsunami amplitudes above the submarine mass failure numerical modeling is used at the sea surface from the common boundary called as liquid boundary with incident waves up to the coastal regions to get the tsunami amplitudes the output of the analytical model is taken as the disturbances for the numerical method in the numerical solutions telemac 2d software system is used for both dispersive and nondispersive modeling the results of the dispersive and nondispersive models are compared to each other both temporal and spatial differences in the amplitudes and wave shapes are examined the obtained results demonstrate that there are no noticeable differences between the dispersion and non dispersion solutions except some special cases and some special landslide velocities

wind driven effects on the yellow sea warm current the yellow sea is a shallow basin writh an average depth of 44 m located between china and the korean peninsula one of the dominant ocean circulation features of the yellow sea is a warm wrater intrusion known as the yellow sea warm current this feature is present throughout the year but reaches its farthest northward extension in winter the circulation of the yellow east china and bohai seas was modeled using the princeton ocean model to better understand the dynamics of the yellow sea warm current the horizontal resolution of the model varies from 8 km in the yellow sea to 25 km in the east china sea twenty four sigma levels are used to define the vertical structure the model uses daily atmospheric forcing from the navy operational global atmospheric prediction system for 1993 open boundary conditions are applied at the taiwan strait the tsushima korea strait an area south of taiwan and the tokara strait with a closed boundary south of the ryukyu islands the model results are examined to determine the effect of the wind on the northward extension of the warm water intrusion using both water mass characteristics and northward velocity components sensitivity tests and spectrum analyses performed to study the influence of the wind on the yellow sea warm current show that winds modify the pathway and extent of the yellow sea warm current the current s origin however appears to be due to external forcing from the current systems developed in the east china sea

an asymmetric upwind flow yellow sea warm current 2 arrested topographic waves in response to the northwesterly wind 1 a warm and salty water mass exists along the yellow sea trough yst in winter this oceanic water mass is distinct from the ambient shelf water and is distributed on the western side of the yst it has long been reasoned that a yellow sea warm current yswc must exist a recent observational study indeed supports the existence of the yswc and shows that its position moved progressively westward as the warm water intrudes further shoreward toward the northwest in this paper we explain mechanisms for sustaining the yswc and for its westward displacement the northwesterly monsoonal wind prevails in the winter and is directed against the yswc the cross trough scale is small compared with the spatial scale of monsoonal variation so one can assume to the first order that the wind stress is uniform across the trough the curl of depth averaged wind stress has opposite signs on the two sides of the trough consequently two oppositely rotating gyres develop initially and they converge along the trough giving rise to a barotropic upwind flow but this upwind flow lasts only for a few days as the two gyres evolve and propagate as topographic waves for a northerly wind both gyres move westward since the positive negative potential vorticity flux on the western eastern side of the trough pushes the water toward shore trough if the bottom friction is negligible the steady response becomes a large anticyclonic gyre over the trough and the upwind current is squeezed toward the shore line in this case no yswc is sustained along or near the trough this runaway warm current can be arrested by a moderate bottom friction we therefore propose that the yswc is actually arrested topographic waves in response to local wind stress forcing

study of the dynamics of wind driven transports into the yellow sea during winter synoptic wind stresses and surface heat flux force a three dimensional numerical ocean model of the yellow sea east china sea dynamics the basin response to winter winds is examined through the model output fields northerly wind bursts are a frequent winter occurrence in this region the wind bursts develop a southward flowing current along the chinese coast as the wind stress forces fluid out of the bohai sea a north south pressure gradient develops as surface water travels from the bohai sea southward decreasing the elevation in the north relative to the elevation in the south also a westward pressure gradient across the yellow sea basin develops in response to the wind forcing the southward pressure gradient forces a bottom flow in the direction opposite to the wind stress this return flow is concentrated in a deep trough located on the eastern side of the basin after the northerly wind ceases the northward transport increases pressure in the north with the result of slowing or stopping the flow northward at times pressure increases in the north sufficiently to force a southward flow in the trough following strong northerly wind events northward transport into the yellow sea occupies the entire trough and may extend into the northern yellow sea bohai sea during periods of calm winds northward flow usually does not penetrate beyond 34 n in the yellow sea this flow is northward on the western side of the island of cheju the flow turns eastward north of cheju and then southward passing through the cheju korea strait the wind stress along the korean coast often deviates from the northerly wind stress over the rest of the yellow sea thus the flow along the korean coast is not as closely related to the northerly wind bursts as the flow along the chinese coast the winter circulation in the yellow sea is predominately a barotropic response to winds with fluctuations due to ekman flow

the calculation of kuroshio current structure in the east china sea early summer 1986 abstract on the basis of hydrographic data and moored current meter records obtained during an early summer cruise may 20 june 23 of 1986 a three dimensional diagnostic calculation of the circulation is performed in the survey area which covers the east china sea continental shelf okinawa trough and an area east of the ryukyu island the kuroshio current condition and structure in the east china sea its branches and their interrelationship as well as the eddies around the kuroshio are discussed when the kuroshio entered the area northeast of taiwan there were two branches the main branch flowed northeastward along the continental slope and the other branch was at the eastern part of the okinawa trough the main axis of the kuroshio followed the continental slope above the 300 m level but moved gradually eastward to the okinawa trough below the 300 m level

modeling study of variable upwelling circulation in the east china sea response to a coastal promontory abstracta three dimensional high resolution numerical model is used to investigate processes and dynamics of an intensified upwelling that is induced by a coastal promontory over the east china sea ecs shelf the center of the intensified upwelling around the promontory has been constantly observed but so far it has been dynamically unexplained forced by an idealized southeasterly wind stress the model results well capture the observed upwelling at the lee of the coastal promontory the intensified upwelling is formed by a strengthened shoreward transport downstream of the promontory as the upwelling jet veers shoreward the jet is mainly controlled by a cross shore geostrophic balance and is largely modulated by both centrifugal acceleration associated with nonlinear advection and by bottom stress the strengthened shoreward transport is mainly attributed to the cross shore geostrophic current that is induced by a countercurrent negative pressure gradient force pgf and partly attributed to th

on the branching of the kuroshio west of kyushu trajectories of satellite tracked surface drifters released in the continental margin area west of kyushu indicate a separation of the inshore side of the kuroshio that appears to form the beginning of the tsushima current the trajectories also indicate an anticyclonic sense of circulation in the area between the separated branch and the eastward directed kuroshio main stream consistent with long term geomagnetic electrokinetograph measurements of surface currents which show a broad southward flow along the west kyushu coast a theory is put forth that ties together these observed flow features in the theory the incidence is considered of an inertial current upon a step rise in topography characterized by a step depth of h0 to simulate the west kyushu coastal bathymetry in an f plane two layered inviscid ocean with a quiescent lower layer the inertial current is of a constant potential vorticity f h where h h0 is the undisturbed upper layer depth and is bounded inshore by a free streamline along which the upper layer depth is a constant hc h the steady state downstream configuration of a separation branch and a deflected main stream along the step is connected to the upstream approach current through the consideration of the constancy of the bernoulli function and the conservation of potential vorticity and mass in the immediate neighborhood of the incidence a complicated flow region is anticipated in which recirculation is featured and an anticyclonic gyre is expected further onto the step the volume integrated balance of along step momentum of the constant potential vorticity flow allows the determination of the angle the branch current makes with the step as a function of the angle of incidence and two depth ratios hc h and h0 h the bifurcation quotient defined as the ratio of the branch current transport to that of the approach current is found to be also such a function except it is independent of the incidence angle these functions yield results that are qualitatively in agreement with the observed bifurcation of the kuroshio west of kyushu that gives rise to the tsushima current

global correlation of the early cambrian of south australia shelly fauna of the dailyatia odyssei zone a lack of well resolved biostratigraphic data has prevented robust regional and global correlation of lower cambrian successions from south australia a new early cambrian biostratigraphy based on data derived from 21 measured stratigraphic sections and drill cores 11 described herein reveals the abundance and diversity of shelly fauna from the arrowie basin and the value of early cambrian small shelly fossils ssf for biostratigraphic studies here we examine shelly fauna associated with the youngest of three recently established biozones the dailyatia odyssei taxon range zone hereafter d odyssei zone and their correlative potential the d odyssei zone features a diverse suite of tommotiids organophosphatic brachiopods bradoriid arthropods molluscs and phosphatic problematica this fauna permits strong correlation often at species level with other major early cambrian terranes particularly antarctica south china and laurentia and suggest a cambrian series 2 stages 3 4 age for the d odyssei zone bradoriids have proven to be useful biostratigraphic tools four new species and three new genera are described herein acutobalteus sinuosus gen et sp nov eozhexiella adnyamathanha gen et sp nov manawarra jonesi gen et sp nov and mongolitubulus descensus sp nov the description of eohadrotreta sp cf zhenbaensis represents the first occurrence of the acrotretoid brachiopod eohadrotreta from australia

provenance discrimination of last deglacial and holocene sediments in the southwest of cheju island east china sea abstract the ultimate provenance of muddy sediment in the southwest of cheju island east china sea remains enigmatic thus far in this study rare earth elements rees were used to investigate sediment provenances of cores e03 6 e03 10 and e03 11 taken from the mud patch discrimination plots based on ree fractionation parameters and trace elements suggest that the sediments deposited during the last deglacial period 15 ka were derived predominantly from the paleo huanghe yellow river which might have delivered sediments directly into the northeastern east china sea during the lowstand of sea level the coarse grained sediments deposited at transgressive stage 15 6 ka were primarily sourced from the changjiang yangtze river and partly from the korean peninsula probably transported by tidal currents in comparison the clayey sediments deposited at highstand stage

the earliest occurrence of trilobites and brachiopods in the cambrian of laurentia abstract the first trilobite to appear in laurentia is a new form resembling the siberian trilobite repinaella the lack of favorable lithologic environment for some distance below suggests that this occurrence is likely to be the oldest in western nevada the trilobites occur on siltstone surfaces and as rare molds in small leached carbonate nodules at parasequence flooding surfaces associated brachiopods are locally abundant these parasequences occur in the lower part of a 50 5 m siliciclastic unit near the top of the andrews mountain member of the campito formation that contains considerable light colored quartzite trace fossils are common and diverse in this interval which is interpreted as a lowstand systems tract below this interval the quartzite is dark gray to dark greenish gray with limited bioturbation of siltstone interbeds suggesting deposition in a dysoxic environment above the trilobite brachiopod bearing interval the siliciclastics are greenish gray also relatively dysoxic and barren of body fossils trilobites reappear suddenly in relative abundance 57 m above first as an eofallotaspis like form marking the base of the montezuman stage then as several species of fallotaspis the occurrence of cf repinaella is approximately correlative with the earliest trilobites in siberia and western gondwana

tsunamis in the sea of marmara historical documents for the past models for the future abstract more than 30 tsunami events have impacted the coasts of the sea of marmara in the past two millennium clustering in izmit bay the shores of istanbul gemlik bay the shores of the kapidag and gelibolu peninsulas with respect to the last well known tsunami the izmit tsunami of 17 august 1999 available field survey run up data and marine surveys provide an opportunity to evaluate how these events were triggered the main purpose of this study is to determine the slope failure potential as a possible tsunamigenic source in the sea of marmara by utilising multi beam bathymetry shallow and deep seismic reflection data on the basis of the landslide geomorphology the generation propagation and coastal amplifications of tsunamis related to earthquake and slope failure scenarios were tested by using tsunami simulation model two layer the maximum water surface elevations near the shores along the north and south coasts are obtained according to the selected scenarios of tsunami generation by using available data

evolutionary paleoecology of the earliest echinoderms helicoplacoids and the cambrian substrate revolution bioturbation in neritic siliciclastic settings during the proterozoic phanerozoic transition increased in depth and intensity causing a change in substrates from the matgrounds characteristic of the proterozoic to the mixgrounds characteristic of the phanerozoic this change in bioturbation increased the water content of surficial layers of sediment and blurred the sediment water interface leading to the first appearance of a mixed layer development of a mixed layer throughout neritic environments would have had a strong impact on any benthic metazoans particularly sessile suspension feeders that were well adapted for survival on relatively unbioturbated proterozoic substrates the impact of this substrate transition on benthic metazoans has been termed the cambrian substrate revolution the unusual early cambrian helicoplacoid echinoderms were well adapted for survival on typical proterozoic style substrates the examination of new helicoplacoid specimens collected during this study combined with extensive study of the rocks in which they are preserved indicate that helicoplacoids lived as sediment stickers on a muddy substrate that underwent only low to moderate levels of strictly horizontal bioturbation and did not have a mixed layer the significant increase of bioturbation through the cambrian in neritic siliciclastic settings is likely to have led to the extinction of the helicoplacoids other similarly adapted sessile suspension feeding echinoderms may have also been driven to extinction by the effects of the cambrian substrate revolution the co existence during the cambrian of organisms adapted to the variety of substrates characteristic of this transitional period may also have contributed to the high degree of perceived morphological disparity during the cambrian explosion

fossilization modes in the chengjiang lagerstatte cambrian of china testing the roles of organic preservation and diagenetic alteration in exceptional preservation abstract one important and poorly understood issue concerning the taphonomy of nonmineralizing organisms in cambrian burgess shale type deposits is the diagenetic pathways by which organisms have become exceptionally preserved scanning electron microscopy sem analyses of exceptionally preserved fossils from the lower cambrian chengjiang deposit of china demonstrate that nonmineralized tissue is preserved in a variety of ways and further suggest that there was some taxonomic control over the precipitation of authigenic minerals during early diagenesis organic preservation is limited to certain decay resistant structures such as heavily sclerotized spines on the claws of anomalocaridids labile organic tissues of nearly all nonmineralizing animals however are preserved by thin films of diagenetic minerals microstructural studies energy dispersive x ray edx analyses and elemental mapping of these minerals indicate that mineral films include apatite pyrite and fe rich aluminosilicates the results support the assumption that early diagenetic mineralization such as phosphatization and pyritization played a key role in the preservation of nonmineralized organisms pyritization seems to be the most important process by which nonmineralizing chengjiang organisms are preserved in exceptional condition precipitation of fe rich aluminosilicates which occurred following pyritization also played a role in the preservation of some chengjiang fossils phosphatization in the chengjiang lagerstatte was evidently rare and limited taxonomically or to animals having large masses of organic material

numerical simulation of the december 1997 debris avalanche in montserrat lesser antilles emplacement of a debris avalanche in the white river valley of southern montserrat lesser antilles on 26 december 1997 was caused by sector failure of the south flank of the active soufriere hills volcano pre and post emplacement surveys of the region indicate a debris avalanche deposit volume of about 40 50 106 m this avalanche is modeled as the gravitational flow of a homogeneous continuum governed by a basal friction law mass and momentum equations are depth averaged over the slide thickness numerical results show that the observed distribution of debris and duration of emplacement is simulated well for a coulomb type friction law with a dynamic friction coefficient dependent upon the thickness and the velocity of the flowing mass

census of the indian springs lagerstatte poleta formation cambrian western nevada usa abstract intervals of exceptional fossil preservation collectively termed the indian springs lagerstatte occur in the middle member of the poleta formation cambrian series 2 stage 3 in esmeralda county nevada usa the preserved macrofauna and taphonomic modes are similar to those of the spence shale lagerstatte of utah cambrian series 3 the indian springs macrofauna mostly consists of biomineralizing organisms such as trilobites helicoplacoids hyolithids and inarticulate brachiopods multi element taxa such as helicoplacoids and chancelloriids are commonly articulated examples of preserved nonbiomineralized anatomy include mantle setae of brachiopods demosponge skeletons hyolithid gut tracts trilobite appendages algae cyanobacteria and body parts of nonbiomineralizing arthropods the indian springs lagerstatte is dominated by fine siliciclastics and was deposited in an offshore shelf setting subjected to storm initiated sediment pulses exceptional preservation was facilitated by obrution type deposition presumably in dysoxic or anoxic muds and in environments where organismic remains were removed from durophagous carnivores and scavengers including bioturbators

a fault controlled trough through a carbonate platform the middle cambrian house range embayment during the cambrian part of western north america was a rapidly subsiding passive continental margin a belt of carbonate deposition dominated the central shelf during middle cambrian time the belt was bounded by fine grained terrigenous sediments that accumulated in deeper water to the west and in a coastal setting to the east rapid and possibly repeated movement along a northeast southwest oriented fault produced a conspicuous eastward re entrant into the carbonate belt the house range embayment in nevada and utah during the middle middle cambrian the embayment was an asymmetrical trough that deepened and widened as it extended 400 km westward across the shelf toward the edge of the continent the trough axis lay near its abrupt southern margin which was a normal fault separating an area of continuous shallow water accumulation to the south from deep water deposition the northern flank of the embayment was initially a drowned platform that formed a southward sloping ramp facies within the embayment represent deposition in an anoxic basin on a deep ramp that was locally steepened and on a shallow low energy ramp the facies rapidly prograded basinward across the northern flank and through vertical accretion a broad carbonate platform was re established there in contrast to the northern flank a continuous sequence of deep water lithofacies accumulated throughout the late middle cambrian in the trough axis of the embayment this region seemingly subsided more rapidly than did that of the northern flank and it may have functioned as a sediment bypass zone although a source of periplatformal carbonates was nearby sedimentation rates in the trough were thus inadequate to re establish a shallow water depositional setting

a numerical study of currents heat advection and sea level fluctuations in the yellow sea in winter 1986 abstract a vertically integrated model that incorporates horizontal temperature variations is used to study the circulation of the yellow sea in a wintertime period for which velocity and temperature measurements are available at several moorings locations along a central trough the model features realistic bottom topography and is forced with wind stress and heat flux fields from 13 january to 22 february 1986 the model also incorporates as a boundary condition sea level fluctuations derived from coastal and insular tide gauge stations along model boundaries in open waters the model reproduces well sea level fluctuations along the coasts of both china and korea the hindcast velocity time series particularly for the north south component track those obtained from direct measurements at the moorings the model momentum balance indicates that the northward flow in the trough is driven by a sea level setup to the south in response to northerly wind bursts in the winter monsoon the sea level fluctuat

numerical modeling of an underwater bingham plastic mudslide and the waves which it generates underwater landslides are a common source of tsunamis in coastal areas theoretical and experimental studies on this problem however are scarce because of the difficulties in modeling and observing a submarine slide and the associated tsunami to study this problem we present a numerical model that simulates the coupling of a bingham plastic mudslide on a gentle uniform slope with the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as an incompressible bingham plastic flow and the water motion is assumed irrotational the long wave approximation is adopted for both water waves and the mudslide dispersion of waves and potential turbulent mixing are not considered the resulting differential equations are solved by a finite difference method we present the numerical results for successive profiles of the mud surface the horizontal velocity distributions of the slide the evolution of the surface elevations and the distributions of the particle velocity of the water motion three major parameters dominate the magnitude of the waves if the volume of the mud is fixed the density of mud the yield stress of the mud and the depth of water at the mudslide site because of the yield stress the slides stop on the slope when the shear stress exerted on the bottom become smaller than the yield stress the bingham plastic behavior of the mud significantly reduces the extent and the speed of the mudslide and also the magnitude of the surface waves generated comparison of the solution of the bingham plastic mudslide model with a snow flow test is presented the solution of a viscous fluid model has been derived as a special case of the present solution

exceptional fossil record distribution of soft tissue preservation through the phanerozoic preservation of soft bodied fossil biotas konservat lagerstaten that preserve traces of volatile nonmineralized tissues readily degraded by bacteria are not evenly spaced through geologic time when compared to outcrop area exceptional faunas appear to be over represented in the cambrian and jurassic these concentrations in time correspond to particular environments indicating that controls on the distribution of exceptional faunas may have operated on a global scale the reduction in the number of exceptional faunas after the cambrian may reflect the evolution and diversification of deep bio turbators specific conditions favoring stagnation and episodic burial were required to ensure preservation in younger rocks

holocene changes in detrital sediment supply to the eastern part of the central yellow sea and their forcing mechanisms in this study holocene changes in the riverine eolian and erosional supplies to the eastern part of the central yellow sea ys and their forcing mechanisms were determined on the basis of multiple mineralogical and geochemical indices of three age dated piston cores from the central yellow sea mud cysm deposition the core records of the indices including clay minerals rare earth element fractionation parameters and conservative trace elements revealed abrupt changes in the sediment sources especially similar to 9 0 and 4 8 ka the late last deglaciation and early holocene sediments units 3 and 4 similar to 14 1 to similar to 9 0 ka most likely originated from the paleo huanghe and the sea bed erosion together with some contribution from the paleo changjiang shoal sediments that extended northeastward into the ys after that period the dominant sediment source gradually changed to the changjiang during the middle holocene similar to 9 0 4 8 ka unit 2 while the supplies from huanghe and sea bed erosion to the south ys decreased in the last 4 8 ka unit 1 the cysm largely received changjiang derived sediments besides some clay sized particulates from the huanghe sea bed erosion and korea rivers might be transported to the cysm during unit 1 possible mechanisms behind such changes in the riverine and erosional sediment sources and contributions include position shifts of river mouths tidal stress evolutions shelf sea level fluctuations east asian monsoon climate changes and the development of the yswc and coastal circulation systems c 2015 elsevier ltd all rights reserved

characteristic features of the north anatolian fault in the eastern marmara region and its tectonic evolution shallow seismic profiles are used to image the tectonic and stratigraphic setting in izmit bay eastern marmara sea four seismic units were detected in the sediments of izmit bay which carry the effects of the tectonic uplift and global sea level variations the area appears to be a negative flower structure controlled by the northern branch of the north anatolian fault in the late pliocene the north anatolian fault reached marmara sea as a master fault smallscale faults were evolved around the master fault under a regime of dextral shear the northward bending of the master fault gave rise to en echelon faults opening the sub basins in izmit bay as releasing bends the secondary faults which developed as low angle oblique to the master fault are also the products of dextral shear to the south short dextral ene wsw trending faults are interpreted as p shears while to the north dextral wnw ese trending faults represents r shears these faults absorbed the deformation at the western end of the ruptured zone during the

interpretation of biological and environmental changes across the neoproterozoic cambrian boundary developing a refined understanding of the radiation and preservational record of early multicellular organisms

the importance of planolites in the cambrian substrate revolution abstract early cambrian subtidal shelf substrates were characterized by low water content and steep chemical gradients conditions likely facilitated by the presence of microbial mats as reflected by an abundance of microbially mediated sedimentary structures in lower cambrian strata such substrate conditions would have been unfavourable for burrowing by benthic metazoans a combination of environmental restrictions and a lack of adaptations to vertical burrowing likely prevented most benthic metazoans from burrowing infaunally in early cambrian subtidal shelf substrates the eventual acquisition of burrowing adaptations by benthic metazoans later in the cambrian promoted an increase in the depth and intensity of bioturbation and initiated a transition toward well hydrated substrates in which extensive infaunal activity was possible siliciclastic units of the lower cambrian succession in the white inyo mountains eastern california contain abundant horizontal bioturbation on bedding planes as documented by bedding plane bioturbation indices but little vertical bioturbation as shown by ichnofabric indices and x radiography planolites a simple horizontal trace fossil represents the dominant type of bioturbation in these units planolites is found in a range of diameters indicating that more than one species of tracemaker likely produced this type of trace although these planolites do not have a vertical component their abundance on bedding planes indicates that the activities of planolites tracemakers had a significant impact on subtidal shelf substrates represented by lower cambrian units in the white inyo mountains early in the cambrian substrate revolution

sar imaging and hydrodynamic analysis of ocean bottom topographic waves 1 the satellite synthetic aperture radar sar images display wave like patterns of the ocean bottom topographic features at the south outlet of taiwan strait ts field measurements indicate that the most ts water body is vertically stratified however sar imaging models available were developed for homogeneous waters hence explaining sar imaging mechanisms of bottom features in a stratified ocean is beyond the scope of those models in order to explore these mechanisms and to determine the quantitative relations between the sar imagery and the bottom features a two dimensional three layer ocean model with sinusoidal bottom topographic features is developed analytical solutions and inferences of the momentum equations of the ocean model lead to the following conditions 1 in the lower layer the topography induced waves topographic waves hereafter exist in the form of stationary waves which satisfy a lower boundary resonance condition kc0 here is an angular frequency of the stationary waves k is a wavenumber of bottom topographic corrugation and c0 is a background current speed 2 as internal waves the topographic waves may propagate vertically to the upper layer with an unchanged wavenumber k if a frequency relation n3 n2 is satisfied here n2 and n3 are the brunt waisala frequencies of middle layer and upper layer respectively 3 the topographic waves are extremely amplified if an upper layer resonance condition is satisfied the sar image of topographic waves is derived on the basis of current modulated small wave spectra the results indicate that the topographic waves on sar images have the same wavelength of bottom topographic corrugation and the imagery brightness peaks are either inphase or antiphase with respect to the topographic corrugation depending on a sign of a coupling factor these theoretical predictions are verified by field observations the results of this study provide a physical basis for quantitative interpretation of sar images of bottom topographic waves in the stratified ocean

sea surface temperature fronts in the yellow and east china seas from trmm microwave imager data abstract swath data from the tropical rainfall measuring mission microwave imager of sea surface temperatures sst from 1998 to 2005 have been used to analyze the climatology and seasonal variability of the sst fronts in the yellow and east china seas yes seven fronts have been identified and placed into three categories namely 1 the shelf break front kuroshio front 2 the coastal fronts zhe min jiangsu shangdong peninsula western korean and western chejudo fronts and 3 the shelf front western yellow sea shelf front the kuroshio front exists from december through may with the maximum sst gradient and highest frontal probability in april the five coastal fronts exist year round all with their maximum sst gradient and highest frontal probability in february the shelf front in the western yellow sea exists only from january to march frontogenesis in winter is due to effects of both air sea heat exchange and advection by currents the coastal fronts in the stratified months are expressed as tidal fronts the coastal frontal zones coincide with the major spawning grounds of fish in the yes the overwintering fishery ground in the yellow sea overlaps with the narrow band of favorable water temperature in the frontal zone the overwintering grounds in the east china sea are broad and bounded by fronts

evidence for three north sea tsunamis at the shetland islands between 8000 and 1500 years ago abstract coastal fen and lake deposits enclose sand layers that record at least three holocene tsunamis at the shetland islands the oldest is the well known storegga tsunami ca 8100 cal yr bp which at the shetlands invaded coastal lakes and ran up peaty hillsides where it deposited sand layers up to 9 2 m above present high tide level because sea level at ca 8100 cal yr bp was at least 10 15 m below present day sea level the runup exceeded 20 m in two lakes we also found deposits from a younger tsunami dated to ca 5500 cal yr bp the sediment facies are similar to those of the storegga tsunami rip up clasts sand layers re deposited material and marine diatoms runup was probably more than 10 m yet another sand layer in peat outcrops dates to ca 1500 cal yr bp this sand layer thins and fines inland and was found at two sites 40 km apart and traced to ca 5 6 m above present high tide the oldest tsunami was generated by the storegga slide on the norwegian continental slope we do not know what triggered the two younger events

a new hypothesis for organic preservation of burgess shale taxa in the middle cambrian wheeler formation house range utah cambrian konservat lagerstatten are the most significant fossil deposits for our understanding of the initiation of phanerozoic life although many modes of preservation may occur these deposits most frequently contain nonmineralized fossils preserved in the form of kerogenized carbon films a rare yet important taphonomic pathway that has not previously been explained for any unit by a comprehensive model the middle cambrian wheeler formation of utah one of these lagerstatten contains abundant kerogenized preservation of nonmineralized tissues which occurs within a distinctive taphofacies that accumulated under the following conditions 1 domination of the siliciclastic fraction by clay sized particles 2 close proximity to a carbonate platform which resulted in mixed carbonate clay sediments 3 a well developed oxygen minimum precluding benthic colonization and burrowing and 4 relative proximity to oxic bottom waters facilitating transport of organisms from a habitable environment to one that favored their preservation we propose that preservation of nonmineralized tissues in the wheeler formation may have resulted from a combination of influences that reduced permeability and thus lowered oxidant flux which in turn may have restricted microbial decomposition of some nonmineralized tissues those influences include near bottom anoxia preventing sediment irrigation by restriction of bioturbation reducing conditions near the sediment water interface that may have acted to deflocculate aggregations of clay minerals resulting in low permeability face to face contacts early diagenetic pore occluding carbonate cements and an absence of coarse grains such as silt skeletonized microfossils fecal pellets or bioclasts this model may be applicable to kerogenized preservation of macrofossils in other fossil lagerstatten

numerical investigation of the generation of continental shelf waves and their role in the westward shift of the yellow sea warm current abstract the yellow sea warm current yswc which carries warm saline water into the yellow sea ys exhibits a typical northward upwind flow during winter observations have shown that the path of the yswc has shifted to the west from the deep trough and it has been suggested that continental shelf waves csws may play an important role in this westward shift however the source of southward propagating csws that drive the westward shift of the yswc remains unclear the objective of this study is to reveal the generative mechanism of csws and their role in driving the westward shift of the yswc numerical models with an idealised topography show that the westward shift of the northward flow propagates southward along the western slope offshore of china with a typical speed of 2 99 m s 1 comparable to the theoretical phase speed of a first mode csw csws driving the westward shift are generated on the northern slope primarily by the scattering of kelvin waves that develop due to northerly winds and propagate northward into the ys along the eastern boundary of the korean peninsula model experiments with a realistic topography consistently support the idea that kelvin wave scattering is a primary source of the southward propagation of the csws that drive the westward shift of the yswc

quantitative reconstruction of holocene sediment source variations in the yellow and northern east china seas and their forcings abstract sediment provenance in the yellow sea and northern east china seas yecss has long been a subject of interest but its quantification is still inconclusive here we present an improved al mg regression analysis by refining its methodological approach to strengthen quantification of sediment source to sink transports in the yecss with focus on its forcing mechanisms during the holocene our quantitative source estimates clearly depict a considerable supply of the chinese river cr sediments 50 to the southwestern korean coastal region and the korean river kr sediments 30 40 to the central yellow sea mud deposit which accounts for a good balance between the sediment supply and budget of the shelf deposit of particular note is an abrupt decline in the cr contributions around 124 e which indicates that the cr sediments do not directly reach the eastern part of the yellow sea blocked by a strong physical boundary further the observed variations in proportions between huanghe changjiang and korean river derived sediments over the last 15 kyr notably an abrupt increase of cr contribution since 7 ka followed by a sudden drop at 3 4 ka exhibit a good correspondence with other mineralogical proxy records these temporal provenance changes witnessed robust palaeoenvironmental signals which fit to major climatic and oceanographic events linked with sea level intensity of the kuroshio current inflow and the east asian monsoon this study improves understanding of what pathways and sinks exist within the yecs basin and how rates of sediment supply from adjacent rivers have changed over time

modeling temperature inversion in southeastern yellow sea during winter 2016 a significant temperature inversion with temperature differences larger than 3 c was observed in the southeastern yellow sea ys during february 2016 by analyzing in situ hydrographic profiles and results from a regional ocean model for the ys this study examines the spatiotemporal evolution of the temperature inversion and its connection with wind induced currents in winter observations reveal that in winter when the northwesterly wind prevails over the ys the temperature inversion occurs largely at the frontal zone southwest of korea where warm saline water of a kuroshio origin meets cold fresh coastal water our model successfully captures the temperature inversion observed in the winter of 2016 and suggests a close relation between northwesterly wind bursts and the occurrence of the large inversion in this respect the strong northwesterly wind drove cold coastal water southward in the upper layer via ekman transport which pushed the water mass southward and increased the sea level slope in the frontal zone in southeastern ys the intensified sea level slope propagated northward away from the frontal zone as a shelf wave causing a northward upwind flow response along the ys trough in the lower layer thereby resulting in the large temperature inversion diagnostic analysis of the momentum balance shows that the westward pressure gradient which developed with shelf wave propagation along the ys trough was balanced with the coriolis force in accordance with the northward upwind current in and around the inversion area

seasonal circulation patterns of the yellow and east china seas derived from satellite tracked drifter trajectories and hydrographic observations abstract we investigated seasonal circulation patterns of the yellow and east china seas yecs by reviewing previous works on the circulation and its dominant currents and taking into account newly compiled trajectories of satellite tracked drifters collected between the 1980s and 2000s the circulation patterns suggested before the 1990s can be categorized into two groups depending on the identified origin of the tsushima warm current in the korea tsushima straits i branching from the kuroshio southwest of kyushu or ii northeastward continuation of the taiwan strait throughflow the branching of the kuroshio southwest of kyushu and northeast of taiwan was clearly evidenced by current measurements and concurrent hydrographic surveys however there is still no clear evidence for the northeastward pathway of taiwan strait throughflow across the mid shelf area of the east china sea target oriented surveys in the 1990s and 2000s employing advanced instruments such as drifter tracking and acoustic doppler current profiler measurements now provide decisive proof of the clockwise rounding of the cheju warm current around jeju do throughout the year of the northeastward extension of changjiang discharge in summer and of the presence of the yellow sea warm current only in winter thus both coastal currents in shallow water and secondary branch currents of the kuroshio such as the yellow sea warm current are found to significantly change from winter to summer to better present the basic pattern of yecs circulation and its seasonality we have constructed seasonal circulations patterns based on review results on the newly compiled drifter trajectories and on hydrographic observations further investigations should be carried out in future with support of comprehensive current measurements on shelf areas and through elaborate numerical modeling

analysis of flow at the gate of taiwan strait 1 a field survey with ship borne acoustic doppler current profiler was carried out across the penghu channel the gate of taiwan strait from 17 to 20 of may 1999 a new method of least squares interpolation is used to separate the mean flow from tidal currents the technique uses gaussian interpolation functions with local support which also take into consideration the anisotropic nature of the flow structure optimal solution is obtained by determining the tradeoff between the misfit and the model order the analysis indicates that the currents in the penghu channel are essentially barotropic and characterized by strong semidiurnal tides and mean flow the along channel averaged tidal velocity amplitudes are 1 2 m s 1 and 0 32 m s 1 for semidiurnal and diurnal tides respectively the mean current is uniform with an average northward velocity of 0 73 m s 1 the total transport is about 1 6 sv which represents a significant mass and material flux into the east china sea

an asymmetric upwind flow yellow sea warm current 1 new observations in the western yellow sea 1 the winter water mass along the yellow sea trough yst especially on the western side of the trough is considerably warmer and saltier than the ambient shelf water mass this observed tongue shape hydrographic feature implies the existence of a winter along trough and onshore current often referred to as the yellow sea warm current yswc however the yswc has not been confirmed by direct current measurements and therefore skepticism remains regarding its existence some studies suggest that the presence of the warm water could be due to frontal instability eddies or synoptic scale wind bursts it is noted that in situ observations used in most previous studies were from the central and eastern sides of the yst even though it is known that the warm water core is more pronounced along the western side data from the western side have been scarce here we present a set of newly available chinese observations including some from a coordinated effort involving three chinese vessels in the western yst during the 2006 2007 winter the data show unambiguously the existence of the warm current on the western side of yst both the current and hydrography observations indicate a dominant barotropic structure of yswc the westward deviation of yswc axis is particularly obvious to the south of 35 n and is clearly associated with an onshore movement of warm water to the north of 35 n the yswc flows along the bathymetry with slightly downslope movement we conclude that the barotropic current is mainly responsible for the warm water intrusion while the ekman and baroclinic currents play an important but secondary role these observations help fill an observational gap and establish a more complete view of the yswc

model simulations of tsunamis generated by the storegga slides abstract a mathematical model based on the hydrodynamic shallow water equations is developed for numerical simulation of water waves generated by the submarine storegga slides on the norwegian continental slope the equations are solved numerically by a finite difference technique computations of wave amplification effects reveal run up heights for the second storegga slide between 3 and 5 m in exposed areas along the eastern coast of greenland iceland and scotland and the western coast of norway the calculated run up heights agree remarkably well with possible tsunami wave heights deduced from geological evidences along the eastern coast of scotland the generated wave heights are strongly dependent on the acceleration of the slide the effects of shear stress at the interface between the water and the slide body has turned out to be important

elongated thoracic spines as potential predatory deterrents in olenelline trilobites from the lower cambrian of nevada abstract repaired injuries offer the opportunity to study predation in the fossil record and test hypotheses concerning predation intensity anti predatory characters and predator selectivity many studies have used the late palaeozoic and mesozoic records but quantitative explorations of early palaeozoic predation especially during the cambrian are lacking trilobites a group of biomineralised arthropods with a high early palaeozoic disparity and diversity are an ideal study system for exploring repaired injury frequencies the ruin wash lagerstatte nevada usa stage 4 cambrian series 2 provides a bulk sample of closely related but morphologically distinct taxa the five most abundant taxa olenellus chiefensis o fowleri o gilberti o terminatus and nephrolenellus geniculatus differ in the spinosity of the cephalon axial lobe of the thorax and thoracic pleural lobes a total of 26 repaired injuries on 330 articulated trilobite cephalothoraces reveal that o terminatus has the highest incidence of repaired injuries repair frequency 0 18 and n geniculatus has the lowest repair frequency 0 043 the role of enlarged spines on the third thoracic segment which are most elongate in n geniculatus are suggested as predation deterrents predator selection for prey of a larger size may have played a minor role though we did not find statistical support for this idea three cephala with repaired injuries were noted in a sample of 685 specimens a much lower repair frequency compared to thoraces this indicates that cephalic attacks were more often fatal when compared to thoracic attacks our study provides the first quantitative support for species specific predation on cambrian trilobites

determination of winter temperature patterns fronts and surface currents in the yellow sea and east china sea from satellite imagery abstract a detailed winter sea surface temperature sst pattern in the yellow sea and east china sea is derived from meteorological satellite thermal infrared images the isotherms in the pattern are calibrated by temperature measurements in situ the features of sst patterns are analyzed using images taken from a variety of satellites dmsp noaa 5 6 gms 1 and tiros n over the last 10 years the winter sst pattern has a sandwich structure which implies that two warm tongues sandwich one cold tongue this pattern starts forming at the end of november has formed by the end of january begins to decline at the end of february and disappears at the end of april in the sst patterns strong coastal fronts can be discerned they are the shandong peninsula coastal front the zhejiang fujian coastal front and the south korean coastal front based on the features of sst patterns and these fronts the winter surface currents are discussed

frontal circulation and westward transversal current at the yellow sea entrance in winter 1 during the wintertime monsoon a tongue shaped thermohaline front is established at the yellow sea ys entrance where the cheju warm current cwc water originating in the kuroshio and the ys cold water meet the frontal circulation as well as the frontal structure has been investigated by analyzing comprehensive conductivity temperature density data float tracks current data and wind data the front develops by the westward advance of the cwc water but it is bounded by the shallow changjiang banks cb that acts like a stopper in the deep part of the ys entrance the northern part of the tongue shaped front displays a wave like motion of 20 km in amplitude and 80 km in wavelength and isotherms isohalines and isopycnals are declined downward toward the north the geostrophic current field indicates formation of a cyclonic circulation along the front which consists of a westward transversal current tc along 34 n and a southeastward outflow along the 50 m isobath of the cb the westward trajectories of floats along the northern front support existence of the tc and a superposition of float tracks evidences cyclonic frontal circulation the new observational findings of the tc and the cyclonic circulation do not match the classical paradigm of a northerly wind driven circulation which consists of the northward inflow through the central trough and the southward outflow on the coastal sides the cyclonic turning of the cold water around the warm tongue stands in contrast with the anticyclonic rounding of the warm cwc water around jeju do

cambrian burgess shale animals replicated in clay minerals although the evolutionary importance of the burgess shale is universally acknowledged there is disagreement on the mode of preservation of the fossils after burial elemental mapping demonstrates that the relative abundance of elements varies between different anatomical features of the specimens these differences reflect the compositions of the minerals that replicated the decaying organism which were controlled by contrasts in tissue chemistry delicate morphological details are replicated in the elemental maps showing that authigenic mineralization was fundamental to preserving these fossils even though some organic remains are also present

summer kuroshio intrusion through the luzon strait confirmed from observations and a diagnostic model in summer 2009 abstract based on current measurements recorded at mooring station n2 20 40 441 n 120 38 324 e hydrographic data and argo observations in the period starting from july 2009 a diagnostic model with a modified inverse method is used to study the circulation in the luzon strait ls a number of new circulation features in the ls are found as follows 1 both observed and modeled currents show that the intruded kuroshio flow northwestward through the ls into the south china sea scs in the upper 400 m during july 2009 2 the diagnostic model confirms that the kuroshio is located in the area east of 121 20 e and west of 122 20 e at 20 00 n there is a meso scale cyclonic eddy at both the surface and 1000 m depth in the area west of the kuroshio near 20 00 n the meso scale cyclonic eddy forced the argo float 1 to make the cyclonic trajectory then the argo float 1 went into the area of the western kuroshio the argo float 1 was tracked as the flow moved northwestward into the scs across the ls in july and august 2009 reflecting the northwestward flow at both the surface and 1000 m depth which coincided with modeled currents these results confirm the northwestward kuroshio intrusion into the scs across the ls in summer 2009 for the first time 3 from the dimensional analysis for the equation of stream function it is seen that the joint effect of the baroclinity and relief jebar and the effect are two important mechanisms on the kuroshio intrusion into the scs in this period this summer kuroshio intrusion results from the weaker upstream kuroshio transport in summer 2009 el nino initiating period due to inertia effects and is associated with a weak volume transport across the ls 2 15 106 m3 s 1 westward 4 after comparison of the dynamics of the kuroshio intrusion during october 2008 and summer 2009 it is clear that these were influenced by the seasonal variability due to the monsoon winds and the interannual variation resulting from the weak upstream kuroshio transport affected by the enso due to inertia effects

the coupling of a submarine slide and the surface waves which it generates underwater landslides are a common source of small scale tsunamis in coastal areas they have been the object of only a few theoretical and experimental studies a numerical model is developed to study the coupling of a submarine landslide and the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as the laminar flow of an incompressible viscous fluid and the water motion is assumed irrotational long wave approximation is adopted for both water waves and the mudslide the resulting differential equations are solved by a finite difference method we present the numerical results which contrast the behavior of the mud flow under a fixed surface in the presence of one way coupling bottom deformations affect the free surface and with full coupling surface pressure gradients react on the mud flow it is found that three main waves are generated by a landslide starting from rest on a gentle uniform slope the first wave is a crest which propagates away from the mudslide site into deeper water this crest is followed by a trough in the form of a forced wave which propagates with the speed of the mudslide front the third wave is a relatively small trough which propagates shoreward two major parameters dominate the interaction between the slide and the waves it produces the density of sliding material and the depth of water at the mudslide site the two way interactions are significant for the cases of a smaller mud density and shallower waters for the cases of larger mud density and shallower waters the two way interactions are small but the waves generated are very large for larger initiation depth of the mudslide the interactions are weak and the waves generated are small we also examined the possibility of a resonance between the slide and the waves our numerical results indicate that a resonance is not expected in many practical cases

scenarios of tsunami amplitudes in the north eastern coast of sea of marmara generated by submarine mass failure in this paper the tsunamis resulting from a submarine mass failure such as slides and slumps triggered by earthquakes or other environmental effects which is settled at the bottom of the north eastern sea of marmara are examined in one sample region as the solution method one hybrid method is developed the main objective of this method is to combine an analytical solution presenting near field tsunami amplitudes above the submarine mass failure with a numerical solution indicating the tsunami amplitudes in the coastal regions for this purpose one common linear boundary between analytical and numerical solution domains is defined movements of submarine mass failures smf are modeled using one simple kinematics source model and the amplitudes of the tsunamis at the region that are closer to the landslide are computed by using the analytical method smf is modeled approximately from the bottom geometry and an average depth is used scenarios of smf are established depending on the velocities and thicknesses of the failure and near field tsunami amplitudes are obtained in the open sea during the source time after the source times the solutions are found in the numerical region using telemac 2d software system with the mentioned boundary above in this boundary the output of the analytical solutions is taken as the boundary conditions or the disturbances for the numerical method with these disturbances the numerical method is performed and the amplitudes are calculated in the coastal area the generation propagation and coastal amplifications of the tsunamis are illustrated at some certain points and regions both in the open sea and near the coast line the results have been visualized and discussed

water characteristics and movements of the yellow sea warm current in summer water characteristics of the yellow sea warm current and its movement in summer are examined from the analysis of the recent hydrographic data collected in adjacent seas of cheju island it is suggested that the yellow sea warm current water in the northeastern china sea is a mixture of western north pacific central water and the yellow sea bottom cold water in the ratio of 7 to 3 it is characterized by salinities of 34 2 s 34 5 and temperatures of 13 t 15 c at depths below 50 m the yellow sea warm current does not seem to extend into the yellow sea as previously believed at least in summer but instead it turns eastward around cheju

does the yellow sea warm current really exist as a persistent mean flow does saline water of kuroshio origin intrude into the yellow sea interior by a persistent mean current through the yellow sea warm current or by an intermittently generated wind driven current this very fundamental question is discussed by analyzing comprehensive conductivity temperature depth data collected over the entire southern yellow sea basin and by analyzing satellite tracked drifter trajectories collected in 1996 and 1997 in the southwestern yellow sea relatively saline water 33 0 34 0 psu persists year round implying a northwestward intrusion of cheju warm current water cwcw this water is a mixture of saline cwcw with salinity higher than 34 0 psu and fresh yellow sea waters with salinity 33 0 psu during the winter monsoon the mixed water distribution is tongue shaped apparently intruding from the cwcw area at the same time a strong thermohaline front with a horizontal form similar to the greek letter forms across the southern entrance of the central yellow sea trough and separates the mixed water area from the cwcw during the summer monsoon the cwcw intrusion is weak and the mixed water that intruded in the previous winter monsoon remains inside the trough as its salinity decreases in winter occasional collapses of part of the front on the western side of the trough are observed presumably in response to an imbalance between northwest currents generated by strong northerly wind bursts and southeast tide induced residual currents saline water in the frontal zone may then flush into the southwestern yellow sea through the collapsed area of the front we conclude that the yswc is not a persistent mean current we also conclude that cwcw may be transported to the southwestern yellow sea in winter by the intermittently generated northwest currents on the western slope of the trough which override the tide induced residual currents that flow to the southeast in this part of the basin

an open ocean forcing in the east china and yellow seas 1 recent studies have demonstrated that the annual mean barotropic currents over the east china and yellow seas ecys are forced primarily by the oceanic circulation in the open ocean basin through the kuroshio current kc the western boundary current of the subtropical gyre in the north pacific ocean the local wind stress forcing plays an important but secondary role those previous results were mainly qualitative and from a simple barotropic model forced by a steady wind stress field they remain to be tested in a more complete 3 d model with both wind stress and buoyancy fluxes in addition the seasonal variability of major ecys currents may involve different forcing mechanisms than their annually averaged fields do and this can only be addressed when a seasonally varying forcing is used in the model in this paper we will address these issues by using a 3 d baroclinic model our results confirm the finding from the previous studies that the kc is the primary forcing mechanism for major annually mean currents in the ecys which include the taiwan strait current the tsushima warm current and the yellow sea warm current yswc etc however the local monsoonal forcing plays a prominent role in modulating the seasonal variability of all major currents in the region a deep northwestward intrusion of the yswc in winter for instance is mainly due to a robustly developed china coastal current and korea coastal current which draw water along the yellow sea trough to feed the southward flows along the west and east coasts of the yellow sea

hydrodynamic processes and their impacts on the mud deposit in the southern yellow sea abstract the sedimentation processes of mud deposits on the continental shelves of the yellow sea ys are investigated using a combined data analysis and hydrodynamic modeling approach in order to identify the dominant factors that contribute significantly to the formation of these deposits the data analysis makes extensive use of existing data especially recently collected deep core data while the hydrodynamic and sediment transport processes are studied using a 3d hydrodynamics model that incorporates the effects of tides waves and wind the average deposit rate of the central yellow sea mud cs is estimated to be 3 6 107 t a 1 based on high resolution chirp sonar profiles combined with core data available sedimentological mineralogical geochemical and fluid flow data all indicate that the fine sediments discharged from huanghe river and changjiang river as well as the resuspended sediments from the old huanghe delta are the main sources for the mud deposits in the southern yellow sea sys this study confirms that tidal current flow is indeed the main agent for transporting the fine sediment to the mud patch in the central sys but wave effect is also significant as it is responsible for maintaining suspension concentration and causing sediment resuspension the wave influence is particularly notable around the old huanghe delta in winter storms as during these storm periods current circulation mainly caused by the asian monsoon can transport a large quantity of fine sediments from the old huanghe delta to the central sys under the present hydrodynamic conditions the modeling results showed that approximately 16 1 33 108 t a 1 of the huanghe river derived sediment is transported out of bohai strait of which around 44 5 72 107 t a 1 will finally be transported to the south yellow sea the corresponding values without accounting for the wave effects are 9 8 and 2 6 respectively it is noted that the deposition rate in the cs mud area over the past 12 kyr is virtually constant despite the significant rise in sea level and associated changes in the tidal current fields and wave distributions in the yellow sea the reason for this is believed to be that the weaker currents and waves during a lower water period is compensated by the shorter distance the suspended sediments have to travel from the paleo huanghe river to the cs mud area thus maintaining a nearly constant deposition rate in the cs mud area

the circulation in the upper and middle layers of the luzon strait during spring 2002 1 on the basis of current measurements at the mooring station and hydrographic and wind data obtained in the luzon strait during spring 2002 the numerical calculation and comparison of circulation were implemented by the aid of a diagnostic model with a modified inverse method during the observation period the directions of subtidal current at the mooring station are mostly northwestward or northward at depths of 200 and 500 m different from those at a depth of 800 m at depths above 400 m most of the kuroshio bypasses the south china sea scs near the luzon strait however both the observed and modeled results show part of the kuroshio flows westward to intrude into the area around the continental slope south of china and the net westward volume transport across the longitudinal section of 120 33 e is about 0 82 106 m3 s 1 in the upper layers from the sea surface to 400 m level at depths below 400 m the directions of flow east of 120 57 e are mostly eastward and the net eastward volume transport across the longitudinal sections of 121 09 e and 121 15 e both are about 2 4 106 m3 s 1 in the middle layers between 500 m and 1200 m this indicates the scs water with a higher oxygen concentration flows eastward into the eastern side of the luzon strait in the middle layer comparison between the observed and modeled results shows they agree basically with each other

taphonomy and depositional circumstances of exceptionally preserved fossils from the kinzers formation cambrian southeastern pennsylvania abstract the emigsville member of the kinzers formation cambrian southeastern pennsylvania is a deposit of exceptional preservation containing three main lithofacies that were part of a mixed siliciclastic carbonate debris fan developed seaward of a carbonate shelf along the appalachian margin of laurentia fossils were exceptionally preserved in a shelf environment subject to tempestite deposition most remains are fragmentary which emphasizes the importance of predation as a taphonomic process where emigsville sediments were deposited remains are preserved mostly as organic carbon films pyrite crusts and aluminosilicate films these preservation styles apparently depended upon the development of microbial consortia in isolated microenvironments and some of the microbes were autolithified sedimentary and biological evidence suggests that anoxia salinity fluctuations and sedimentary obrution played relatively minor roles in the emigsville member of the kinzers formation the abundance of exceptionally preserved remains suggests that exceptional sedimentary conditions were not necessary in the cambrian in order for exceptional preservation to occur the abundance of predation evidence in a deposit of exceptional preservation reinforces the concept that predation was the primary taphonomic filter during cambrian time

generation and propagation of nonlinear internal waves in massachusetts bay 1 during the summer nonlinear internal waves nliws are commonly observed propagating in massachusetts bay the topography of the area is unique in the sense that the generation area over stellwagen bank is only 25 km away from the shoaling area and thus it represents an excellent natural laboratory to study the life cycle of nliws to assist in the interpretation of the data collected during the 1998 massachusetts bay internal wave experiment mbiwe98 a fully nonlinear and nonhydrostatic model covering the generation shoaling region was developed to investigate the response of the system to the range of background and driving conditions observed simplified models were also used to elucidate the role of nonlinearity and dispersion in shaping the nliw field this paper concentrates on the generation process and the subsequent evolution inthe basin themodel was foundtoreproducewell the range of propagation characteristics observed arrival time propagation speed amplitude and provided a coherent framework to interpret the observations comparison with a fully nonlinear hydrostatic model shows that during the generation and initial evolution of the waves as they move away from stellwagen bank dispersive effects play a negligible role thus the problem can be well understood considering the geometry of the characteristics along which the riemann invariants of the hydrostatic problem propagate dispersion plays a role only during the evolution of the undular bore in the middle of stellwagen basin the consequences for modeling nliws within hydrostatic models are briefly discussed at the end

summertime hydrographic features in the southeastern hwanghae abstract ctd casts in the southeastern hwanghae yellow sea were made in august 1983 and 1984 to describe the spatial structure of the summertime hydrographic features cold coastal water appeared around the southwestern coast of korea which was formed by strong tidal stirring tidal mixing in the study area seems to have been enhanced by the presence of many small islands in the deeper region beyond the tidal front stratification became much stronger and the bottom layer below seasonal thermocline was occupied mostly by the hwanghae cold water characterized by a temperature lower than 10 c and salinity of 32 5 33 0 the northeastward extension of the changjiang diluted water was shown by a tongue like plume of relatively warm fresh water confined to the thin surface layer 10 m thick there was no evidence for the hwanghae warm current carrying high salinity water into the eastern hwanghae along the korean coast the warm current was found to flow in a narrow band close to the west and north coast of chejudo cheju island and then to pass eastward through the cheju strait thus the eastern part of the cyclonic circulation in the surface layer cannot be considered to be a northward continuation of the hwanghae warm current the local salinity maximum in the lower layer off kunsan and the higher salinity on the west side of the central trough than on the east side would imply a northward flow on the west flank of the trough to compensate for the southward intrusion of the hwanghae cold water from which an anticyclonic circulation could be expected in the lower layer

tongue shaped frontal structure and warm water intrusion in the southern yellow sea in winter 1 in winter a thermohaline front forms at the yellow sea ys entrance where the warm and saline cheju warm current cwc water meets cold coastal water the frontal structure as well as the northwestward intrusion of the warm water was investigated by analyzing conductivity temperature depth ctd data tracks of drifting floats moored current data and satellite images the cwc water advances westward as a tongue with its tip heading westward across the ys entrance not intruding northward along the deepest part of the ys trough whereas a secondary warm water band is developed northwestward along the western flank of the trough floats in the warm tongue moved northwestward across the western frontal zone where the frontal structure was weak reflecting the northwestward intrusion along the 50 70 m isobaths through the frontal zone currents in the trough do not always meet the upwind flow theory that in an elongated basin the wind driven flow is upwind in the deep channel but rather show the predominance of the southward downwind flow model experiments show that on the western flank of the trough both the southeastward tide induced residual flow and the southeastward flow due to the nonlinear effect between tide and wind are generated at the same time thus the intermittent intrusion of the cwc across the western frontal zone may be closely associated with the predominance of the upwind flow over the southeastward nonlinear interacted flow

effects of the yellow sea warm current on the winter temperature distribution in a numerical model 1 the temperature distribution and circulation patterns in the yellow sea ys are examined by using a wave tide circulation coupled numerical model this model sufficiently reproduces the variation of the warm tongue structure of the yellow sea warm current yswc from the double branches flowing along the ys trough and the western 60 m isobath in january to the single stream along the western temperature front in march this is observed in both the long term monthly climatology and the satellite based sea surface temperature images in recent years examining the local heat balance in the numerical model during the entire cooling period it is found that the yswc has a very important influence on the ys warm tongue structure compared with the surface cooling the influence of the advection is small in the coastal shallow area but large in the deep warm tongue area up to 50 of the magnitude of heat flux although bathymetry is the essential factor which causes the temperature front the yswc is the key factor which positions shapes and maintains the warm tongue structure this helps to affirm the existence of the yswc at least as a monthly mean flow however more high resolution current observations in deeper layers west of cheju island and the western fork of the ys trough are needed to confirm the existence of the yswc and its characteristic timescale in the real ys

temperature inversion in china seas temperature inversion was reported as a common phenomenon in the areas near the southeastern chinese coast region a west and south of the korean peninsula region b and north and east of the shandong peninsula region c during october may in the present study based on hydrographic data archived from 1930 through 2001 319 029 profiles the inversion was found to be remarkable with obvious temporal and spatial variabilities in both magnitude and coverage with higher probabilities in region a up to about 60 and region c 40 50 than in region b 15 20 the analysis shows that seasonal variation of the net air sea heat flux is closely related to the occurrence time of the inversion in the three areas while the yangtze and yellow river freshwater plumes in the surface layer and ocean origin saline water in the subsurface layer maintain stable stratification it seems that the evaporation excessive precipitation flux makes little contribution to maintaining the stable inversion advection of surface fresh water by the wind driven coastal currents results in the expansion of inversion in regions a and c the inversion lasts for the longest period in region a october may sustained by the taiwan warm current carrying the subsurface saline water while evolution of the inversion in region b is mainly controlled by the yellow sea warm current

significance of molluscan shell beds in sequence stratigraphy an example from the lower cretaceous mannville group of canada1 detailed study of marine shales the ostracod zone within a cretaceous third order transgressive regressive sequence in the alberta foreland basin reveals a systematic association between shell beds and parasequence scale flooding surfaces including surfaces of maximum flooding the ostracod zone a subsurface lithostratigraphic unit known as the calcareous member in outcrop consists of 10 20 m of black shale and bioturbated sandstones with many thin fossiliferous limestones parasequences shallowing up cycles 2 3 m thick were delineated within this transgressive unit based on lithology sedimentary structures degree of bioturbation dinoflagellate diversity total organic carbon and carbon sulphur ratios many flooding surfaces are firmgrounds or hardgrounds shell rich limestones occur in three different positions relative to these flooding surfaces and each has a distinctive bioclastic fabric and origin i base of parasequence shell beds bops lie on or just above flooding surfaces in the deepest water part of a parasequence they are thin up to a few centimetres graded or amalgamated skeletal packstones wackestones composed of well sorted granular shell and are interpreted as hydraulic event concentrations of exotic shell debris ii top of parasequence shell beds tops are capped by flooding surfaces at the top shallowest water part of a parasequence they typically are several decimetres thick are physically amalgamated packstones grainstones or bioturbated wackestones and contain abundant whole as well as comminuted shells these are composite multiple event concentrations of local shells iii mid sequence shell beds rest on as well as are capped by firmgrounds or hardgrounds and are intercalated between parasequences in the deepest water part of the larger sequence they are laterally extensive lime mudstones a few decimetres thick with sparse shells in various states of dissolution recrystallization and replacement these beds are terrigenous starved hiatal concentrations and record maximum flooding within the ostracod zone offshore sections of the ostracod zone typically contain several starved mid sequence shell beds underscoring the difficulty of identifying a single maximum flooding surface within a third order sequence