modification of a linear bar trough system by a standing edge wave abstract detailed fluid motions and bathymetric changes in the lacustrine nearshore zone at wymbolwood beach georgian bay canada were monitored during storms to test theoretical postulates about the importance of low frequency wave motions to nearshore circulation of water and sediments eighteen continuous resistance wave staffs and two electromagnetic current meters were deployed along one shore normal and two shore parallel instrument arrays over a period of two months during one intense storm a mode 3 standing edge wave at 0 035 hz was the predominant low frequency motion prior to the storm the bathymetry was characterized by linear bar trough systems and during the storm these features migrated onshore and became rhythmic in response to the length scales and relatively fixed locations of nodal and antinodal lines of the standing edge wave however a well defined crescentic bar as predicted by the model under the condition of zero net sediment flux divergence did not evolve because the hydrodynamic forcing ceased before an equilibrium condition could be attained nevertheless the location of scour and accretion features demonstrated the tendency towards such a crescentic form the offshore and alongshore irregularities of the post storm bathymetry are not readily explained by alternative hydrodynamic interactions

changes in coral reef structure through the miocene in the mediterranean province adaptive versus environmental influence well documented mediterranean examples of miocene carbonate platforms with complete exposures from shallow water to basinal facies provide evidence for temporal changes in reef building capacity of zooxanthellate corals in pre late tortonian platforms small coralgal patches and mounds occur from platform top to the toe of slope but they did not build to sea level in contrast barrier reefs with unequivocal reef crest structures that reached sea level are documented in late tortonian early messinian platforms we suggest that a change in both calcification rates and bathymetric zonation was the result of coevolution of corals and symbiodinium zooxanthellae coeval to global cooling and at least at a regional scale a geochemical change that supported widespread aragonite precipitation through the late miocene

the miocene pakhna formation southern cyprus and its relationship to the neogene tectonic evolution of the eastern mediterranean abstract the miocene pakhna formation is interpreted as relating to onset of the present northward subduction of the african plate beneath cyprus and is thus critical to understanding of the neogene evolution of the eastern mediterranean basin following a perios of deep water pelagic chalk deposition in the late eocene and oligocene upper lefkara fm the pakhna formation records heterogeneous mainly carbonate sedimentation the pakhna formation is bounded by the limassol forest block an uplifted ophiolitic terrain to the north and by the akrotiri high a ridge of exotic mesozoic lithologies to the south two sub basins maroni in the e and khalassa in the w within the pakhna formation were separated by the wnw ese trending yerasa lineament located near the s margin of the ophiolite in most areas the pakhna formation overlies the lefkara formation disconformably the succession begins with deep water pelagic carbonates and shows increased input of shallow water bioclastic and terrigenous sediment upward during the early to mid miocene the ophiolitic terrain to the n was uplifted deformed and eroded followed by marine transgression and patch reef development in the tortonian late miocene ophiolite derived clastics were mixed with shallow water bioclastic sediment reworked in a high energy coastal setting and transported downslope within channels into the basin accumulating as massive sands debris flows and calciturbidites in the maroni sub basin localised debris aprons prograded into a pelagic carbonate environment to the se further west in the khalassa sub basin little uplift occurred along the basin margins and redeposited sediment was mainly bioclastic contrasting sediment including chert was derived from the allochthonous mamonia complex exposed on the akrotiri high to the s and its possible offshore extension bioclastic sediment including reef talus was also derived from an intrabasinal high in the khalassa sub basin eventually normal marine deposition was ended by the messinian salinity crisis

infragravity wave dynamics in a barred coastal region a numerical study this paper presents a comprehensive numerical study into the infragravity wave dynamics at a field site characterized by a gently sloping barred beach the nonhydrostatic wave flow model swash was used to simulate the local wavefield for a range of wave conditions including mild and storm conditions the extensive spatial coverage of the model allowed us to analyze the infragravity wave dynamics at spatial scales not often covered before overall the model predicted a wavefield that was representative of the natural conditions supporting the model application to analyze the wave dynamics the infragravity wave field was typically dominated by leaky waves except near the outer bar where bar trapped edge waves were observed relative contributions of bar trapped waves peaked during mild conditions when they explained up to 50 of the infragravity variance near the outer bar the infragravity wave growth was partly explained by nonlinear energy transfers from short waves this growth was strongest for mild conditions and decreased for more energetic conditions when short waves were breaking at the outer bar further shoreward infragravity waves lost most of their energy due to a combination of nonlinear transfers bottom friction and infragravity wave breaking nonlinear transfers were only effective near the inner bar whereas near the shoreline where losses were strongest the dissipation was caused by the combined effect of bottom friction and breaking this study demonstrated the model s potential to study wave dynamics at field scales not easily covered by in situ observations

edge waves on nonplanar bathymetry and alongshore currents a model and data comparison the numerical solutions for the dispersion of linear shallow water edge waves are compared with observed alongshore wavenumber frequency spectra of edge wave variance to examine their prediction of the effects of nonplanar bathymetry and moderate mean alongshore currents field observations were made at the two southern california nearshore sediment transport study field sites torrey pines 1978 and leadbetter 1980 beaches on torrey pines beach where the bathymetry is very planar except for a concave steepening landward beach face observed departures from the analytical plane beach dispersion solution attributed to the concave face are predicted by numerical dispersion solutions using the measured cross shore depth profile on both beaches asymmetry in observed dispersion curves of upstream and downstream progressing edge waves are well predicted by numerical dispersion solutions using the cross shore profile of measured mean alongshore current spectra of the alongshore velocity component from both beaches show changes in edge wave mode dominance with increased frequency oltman shay and guza 1987 demonstrated that mode dominance transition with frequency as observed from a fixed offshore location is associated with the seaward decay of edge waves and that the approximate frequency of mode transition is predicted by the profile solutions for edge wave variance and the assumption of equal shoreline elevation variance amongst modes a submerged concave beach face at torrey pines beach is shown to alter the predicted cross shore scaling of the edge wave profiles from that predicted when mean water is below the concave beach face and therefore to alter the mode transition frequency predictions different mode transition frequencies are observed in spectra from data runs with mean water levels both above and below the concave beach face and the differences are shown to be reasonably predicted using edge wave profile solutions for the measured beach profile for these data observed and predicted mode transition frequencies did not change appreciably in the presence of mean alongshore current implying that large changes in cross shore scaling of the edge wave profiles did not occur however as has been previously shown by howd et al 1992 there are also local edge wave profile shape changes because of the cross shore shear of the mean alongshore current verification of these predicted local shape changes can not be made with these data confidence in cross shore profile solutions is of practical importance for estimates of shoreline variances from offshore measurements on these two beaches estimates using both numerical solutions for the measured depth and current profiles and analytical solutions for plane beach approximations typically differ by only 10 to 40

exploration plays in the mersin basin turkish mediterranean sea there are a number of large neogene basins in the ne mediterranean region including the antalya mut mersin adana iskenderun and northern part of latakia basins figure 1 the broader area is subdivided by major structural features such as the aksu missis andirin kyrenia zone ecemis fault goksu fault and dead sea east anatolian faults figure 2 there are some locally important smaller fault systems as well that trend approximately parallel to the major structures e g kozan aslantas and yumurtalik faults

the influence of long waves on macrotidal beach morphology the aim of the following paper is to demonstrate that standing long waves can generate intertidal morphological features in a dissipative macrotidal setting in this environment the tidal excursion can exceed the length scales associated with long waves this extends the work of simmonds et al 1995 in which it was shown that monochromatic long waves could generate sediment convergence patterns that bore a good similarity to observed topographic features namely ridges and runnels from a field site on the belgian coast the simulation is modified to include a band of long waves and it is found that a good correspondence with real topography can still be achieved on a tidally averaged basis by allowing for a degree of uncertainty in the breaking criterion it is also argued why the observed scales are more likely to correspond with the shorter end of the long wave spectrum the simulation helps to shed light on the conditions in which such features are known to form

impact of carbonate producing biota on platform architecture insights from miocene examples of the mediterranean region abstract different types of carbonate platforms formed in the mediterranean during the miocene low angle homoclinal types of ramp distally steepened ramps flat topped platforms and reef rimmed shelves the critical differences between these platforms result from differences in the capacities of the carbonate systems to accumulate sediments above hydrodynamic base level ecologically controlled accommodation the various depositional profiles and facies belt distributions resulted from the interplay between different sediment production and redistribution processes and the internal architectures resulted from the response of each type of platform to changes in accommodation heterogeneities driven by high frequency sea level cycles are maximized in platforms ruled by shallow water euphotic framework dominated production and minimized in low angle ramps where sediment resulted from aphotic and oligophotic carbonate production in the mediterranean region there is no direct relationship between type of platform and global temperature as shown by the coeval occurrence of different platforms in similar latitudinal settings although temperature is a key limiting factor other paleoceanographic factors such as trophic resources may have also been along with biological evolution important factors influencing different types of carbonate producing biotas

the dagpazari carbonate platform mut basin southern turkey facies and environmental reconstruction of a coral reef system during the middle miocene climatic optimum abstract plate tectonics and climate change have deeply influenced the evolution of coral reef systems of the mediterranean during the miocene most of this information is based on studies of coral reefs from the western and central sectors of the mediterranean this study reports facies analyses sr isotope stratigraphy and environmental reconstructions of the dagpazari coral reef system located within the mut basin in southern turkey stratigraphic correlations and sr isotope ratios on several oyster shells date the dagpazari reef to the early langhian ten different facies have been recognized and their arrangement has led to the identification of two main depositional units interpretation of the biotic associations indicates that the dagpazari depositional system developed constantly within the euphotic zone the reef framework was mainly built by massive faviid and poritid zooxanthellate corals whereas loose grain sediments were essentially produced by halimeda coralline red algae or influenced by the presence of seagrass colonizations this study highlights for the first time the great importance of halimeda as sediment producer in the eastern mediterranean coral reef systems this role is related to the common occurrence of halimeda plates within almost all the reef facies but especially to the presence of large in situ bioherms dominated by the algal segments dagpazari langhian halimeda bioherms also represent the oldest of these structures so far recorded in the fossil record the development of the dagpazari platform was mainly controlled by eustatic fluctuations of the sea level and by the morphology of the antecedent substrate in particular the occurrence of a pre existent topographic high promoted the constant presence of shallow water environments throughout the depositional history of the reef system with the production of euphotic carbonates both landward and basinward and the consequent formation of a small elliptical platform 87sr 86sr ages place the dagpazari reef system exactly within the middle miocene climatic optimum phase the most recent warm phase of the earth this suggests that zooxanthellate corals were able to exert their reef building capacity in shallow water settings even during periods of global warming thus being not exclusively an adaptation to cooling climates as proposed in the recent debates

pinning points a method providing quantitative constraints on relative sea level history abstract quantitative constraints on the history of relative sea level allow for a better understanding of the controls on depositional sequence development the constraints are provided by pinning point curves plots of ancient relative sea level elevations pinning points versus time constructing a pinning point curve requires identification of ancient stratigraphic positions of sea level through interpretation of facies and surfaces formed at sea level then their ancient relative elevations are determined through reconstructing aspects of ancient paleotopography upper miocene strata from las negras southeastern spain preserve paleotopography contain ancient surfaces of subaerial exposure and contain facies deposited near sea level the pinning point curve illustrates a complex relative sea level history with large and small scale relative sea level fluctuations defined by 31 pinning points

seagrass related carbonate ramp development at the front of a fan delta burdigalian new caledonia insights into mixed carbonate siliciclastic environments abstract past shallow water carbonate environments of the main island of new caledonia nc have been subject to high terrigenous influx derived from the erosion of ultramafic obducted nappes and are therefore a relevant case study for characterizing neritic carbonate production in mixed carbonate siliciclastic systems under a tropical climate more particularly we focused on burdigalian carbonate sedimentary records cropping out on the western coast of nc in the nepoui area based on a comprehensive sedimentological study of cores and outcrops we established a new depositional model of an alluvial fan to carbonate ramp transition shallow water euphotic carbonate production was dominated by seagrass related biota and corals derived from small sized bioconstructions extensional tectonics and associated normal faulting driven by post obduction isostatic rebound favored carbonate ramp aggradation and preservation the carbonate ramp was incised by conglomerate filled terminal distributary channels which indicate that terrigenous inputs remained significant during marine transgression and did not inhibit the development of seagrass and scleractinian carbonate factories phytal substrates induced by seagrass and or macro algae seafloor colonization strongly controlled the nature of carbonate production and promoted the accumulation of foraminiferal coralline algal sediments seagrass development at the front of the fan delta is interpreted to have controlled the preservation of a diverse and significant carbonate production by reducing water turbidity and by limiting the risk of suffocation for filter feeding biota in such a high terrigenous influx setting

field observations of beach cusps and swash motions abstract we tested the hypothesis of cusp formation by the longshore structure of synchronous or subharmonic mode zero edge waves using detailed field measurements of foreshore topography incident waves and swash motions two distinct intervals of cusp formation were observed alongshore separated swash measurements were analyzed to detect structures at wavelengths and frequencies consistent with the measured cusp spacings for both events no statistical support for cusp generation by the traditional subharmonic or synchronous edge wave mechanisms was found however once cusps became well developed there was evidence of interaction between fluids and topography at a wavelength equal to the cusp spacing but at the period of the incident swash we propose that this interaction could have been responsible for the generation of the second set of cusps with a spacing of half the pre existing cusp wavelength

coastal geomorphology through the looking glass abstract coastal geomorphology will gain future prominence as environmentally sound coastal zone management strategies requiring scientific information begin to supplant engineered shoreline stabilization schemes for amelioration of coastal hazards we anticipate substantial change and progress over the next two decades but we do not predict revolutionary advances in theoretical understanding of coastal geomorphic systems paradigm shifts will not occur knowledge will advance incrementally we offer predictions for specific coastal systems delineated according to scale for the surf zone we predict advances in wave shoaling theory but not for wave breaking we also predict greater understanding of turbulent processes and substantive improvements in surf zone circulation and radiation stress models very few of these improvements are expected to be incorporated in geomorphic models of coastal processes we do not envision improvements in the theory of sediment transport although some new and exciting empirical observations are probable at the beach and nearshore scale we predict the development of theoretically based two and three dimensional morphodynamical models that account for non linear time dependent feedback processes using empirically calibrated modules most of the geomorphic research effort however will be concentrated at the scale of littoral cells this scale is appropriate for coastal zone management because processes at this scale are manageable using traditional geomorphic techniques at the largest scale little advance will occur in our understanding of how coastlines evolve any empirical knowledge that is gained will accrue indirectly finally we contend that anthropogenic influences directly and indirectly will be powerful forces in steering the future of coastal geomorphology if you should suddenly feel the need for a lesson in humility try forecasting the future kleppner 1991 p 10

miocene recent evolution of the western antalya basin and its linkage with the isparta angle eastern mediterranean abstract interpretation of 9500 km of multichannel seismic reflection profiles showed the presence of two major tectonic histories in western antalya basin spanning from the miocene or older to the pliocene quaternary a prominent fold thrust belt affects the miocene succession in the offshore the thrusts swing from a nw se strike with sw vergence in the northeast of the mapped area to a more northerly strike with westerly vergence at the western shelf edge of the deep basin the miocene deformation appears to continue offshore from the westerly directed thrusting seen onshore that characterizes the eastern edge of the isparta angle the contraction is consistent with the counterclockwise miocene rotation of the western side of the isparta angle determined from paleomagnetic studies the thrust belt forms the western extremity of the wider regional aksu kyrenia misis oroclinal culmination the tectonic activity experienced a period of relative quiescence across the western antalya basin during the messinian a major kinematic change occurred in the pliocene when the regional strain was partitioned into three spatially localized tectonic domains an extensional domain confined to the pliocene quaternary unit 1 occupied the northeastern portion of the study area a predominantly extensional domain with a few re activated pre existing miocene contractional structures occupied the southern and central portion of the study area and an extensional and or transtensional domain occupied the continental shelf and slope in the westernmost antalya basin these complexities relate to strike slip motions as the crustal block within the isparta angle moved northwards relative to the blocks to the north

infragravity waves over a natural barred profile measurements of cross shore flow were made across the surf zone during a storm as a nearshore bar became better developed and migrated offshore measured infragravity band spectra were compared to synthetic spectra calculated numerically over the natural barred profile assuming a white run up spectrum of leaky mode or high mode edge waves as in earlier studies the spectra compared closely however for some frequencies the energy of the measured spectrum exceeded the energy of the synthetic spectrum suggesting that the run up spectrum was not white but had dominating frequencies utilizing cross shore flow data and synthetic spectra from a number of cross shore locations an equivalent run up spectrum was calculated for each day on the first day of the storm the equivalent run up spectrum indicated a dominant wave that had a node in velocity reasonably close to the bar crest later during the storm when the bar had migrated farther offshore there was no evidence for a dominant motion having a velocity node at the bar crest the structure of the equivalent run up spectrum compared well with spectra of direct measurements of run up obtained several hundred meters away we have no clear evidence in support of the theory that infragravity waves might form or force the offshore migration of a bar to confirm this finding longer records obtained synoptically over a developing bar are required the dominant wave observed early in the storm was consistent with symond and bowen s 1984 theoretical prediction of resonant amplification of discrete frequencies over a barred profile

on vertical motion divergence and the thermal wind balance in cold dome meanders a diagnostic study wavelike meanders are observed along the length of the florida current from the florida keys to cape hatteras these propagating meanders are three dimensional each has a cold dome and the meandering flow that overtakes the dome in a cyclonic turn is characteristically stronger when flowing offshore than when flowing onshore we focus on vertical motion as a key to understanding the interdependence of the downstream propagation the upwelling in the cold dome and the skewness in the strength of the meandering flow inferred from a composite of drogue and temperature observations the pattern of vertical motion is one of upwelling that extends throughout the water column formed by the forepart of the translating dome and its overlying on shore flow and a downwelling that similarly extends vertically through the rear part of the dome and its overlying offshore flow it is shown that the vertical motion and the translation of the meander are interrelated and both enter importantly in the acceleration of the water columns and hence in the skewness in the strength of the meandering flow component as the thermal wind changes with the divergence accompanying the vertical motion it also provides a twisting mechanism to help restore the thermal wind balance

observations of swash under highly dissipative conditions video measurements of swash were made at the low sloping beach of the multiple bar system at terschelling netherlands the majority of the measurements were conducted under highly dissipative conditions with iribarren numbers 0 the ratio of beach slope to the square root of offshore wave steepness less than 0 2 infragravity 0 004 0 05 hz waves dominated the swash with an average ratio of infragravity and total swash height rig r of 0 85 using linear regression we investigated the dependence of swash parameters on environmental conditions such as short wave height period and local beach slope on average rig was about 30 of the offshore wave height h0 the slope in the linear h0 dependence of rig amounted to only 0 18 considerably smaller than that observed on steeper beaches the data set shows evidence for saturation of the higher infragravity frequencies for 0 less than roughly 0 27 in our opinion this saturation caused the constant of proportionality in the linear relationship between rig h0 and 0 to be significantly larger than that observed under higher iribarren number regimes the saturated tails of the swash spectra had an approximate f 3 roll off where f is frequency whereas in general the nonsaturated parts were white this lack of significant peaks casts doubt on the causality between infragravity waves and nearshore bars

near bottom cross shelf heat flux along central florida s atlantic shelf break winter months near bottom current and temperature data from a 154 day period in winter 1984 1985 are combined to investigate cross shelf heat fluxes along central florida s atlantic coast between 27 and 30 n temperature and current time series recorded at the shelf break exhibit considerable variability over time scales of the order of 1 2 weeks low frequency temperature fluctuations superimposed onto a seasonal cooling of approximately 0 4 c week decrease from south to north cross shelf motion results in little net displacement at latitudes 27 and 30 n but results in considerable net shoreward displacement at latitude 28 n cross shelf heat flux is shoreward at all study sites but values decrease approximately linearly from south to north the study shows that a shoreward flux of relatively cool water can continue through winter months in the vicinity of cape canaveral compared with summer up welling in the same area the characteristic time scale is considerably shorter because the heat flux appears to be related to frontal eddies embedded in the cyclonic shear zone of the florida current rather than to seasonal variations in volume transport combined with a westward shift of the axis of the florida current

a revised stratigraphic framework for later cenozoic sequences in the northeastern mediterranean region this study describes the lithostratigraphic character of mid cenozoic oligocene pliocene sequences in different parts of the northeastern mediterranean area and offers a detailed stratigraphic correlation for this region the sequences concerned are drawn from the camardi area south central anatolia the adana basin the misis mountains and the kyrenia range northern cyprus and the submerged florence rise west of cyprus the stratigraphic relationships identified here indicate the following a following the middle eocene lutetian regression there was uplift throughout the entire region b episodes of fluvial and lacustrine deposition in intramontane settings ensued in most of this region during the late eocene early miocene interval c following a regionally extensive phase of tectonic compression major marine transgression commenced in the late oligocene in northern cyprus and in the early miocene in adjacent southern turkey with the exception of the ecemi fault zone where continental deposition continued d these oligo miocene transgressive sequences comprise a broadly diachronous complex of both shallow and deeper marine facies including reefal carbonates littoral clastics basinal shales and fan turbidites e deeper marine miocene facies persisted longer in the misis area and in northern cyprus f a regional regression occurred throughout most of the area during the late serravallian to tortonian interval and is marked by the abrupt locally discordant appearance of extensive shallow marine deltaic and fluvial deposits g continued regression in the messinian led to the formation of significant evaporite deposits in the western and southern parts of the region but localized uplift of the misis area is attested by the initial deformation of the neogene rocks there and the absence of messinian sediments from this area h in the pliocene there was extensive emergence of the northern parts of the region interrupted by brief marine incursions the present day drainage pattern was established at this time i marine conditions persisted longer in northern cyprus where emergence occurred only in the latest pliocene

edge wave trapping and amplification on barred beaches theoretical predictions show that edge waves may be trapped on bars providing a possible mechanism for bar growth simple solutions to the linear shallow water equations reveal that bar trapping is controlled by the depth of the water over the bar hbar and the geometry of the inshore trough relative to the bar for specific geometries amplification over the bar approaches an order of magnitude or more as the phase speed approaches where amplification is defined as the surface displacement over the bar relative to the surface displacement at the shoreline the amplification increases with the cross shore length scales of the profiles the amplification is somewhat frequency dependent generating stronger currents at the location of the bar in specific frequency ranges previous work showed that particular edge wave modes have the correct length scales to generate beach features such as bars and beach cusps but field observations notably shoreline run up data frequently show no evidence of edge wave energy being concentrated at the appropriate frequencies however for bar trapped modes edge wave energy is concentrated at the location of the bar therefore this edge wave energy will not necessarily be evident in shoreline measurements strong correlation exists between the energy distribution of the longshore component of the orbital velocity observed in data collected at superduck october 11 1986 and the distribution expected for a white edge wave spectrum at the shoreline this suggests that bar trapped edge waves exist in particular at incident wave frequencies

bimodality of the kuroshio abstract a barotropic ocean model is used to study the bimodal behavior of the kuroshio to the south of japan by considering the combined effects of the beta plane the kyushu coastal perturbation the izu ridge and the sw ne tilted coastline the two frequently observed meander patterns have been numerically verified as the two quasi steady solutions contained n the model the small meander state is identified as an upstream disturbance largely forced by the izu ridge its width decreases as the strength of the current increases the large meander state is forced by the presence of both the kyushu wedge and the izu ridge topography for small volume transports the large meander state behaves like the small meander state in that the meander width decreases as the current speed increases for large volume transports it behaves like a lee rossby wave in that the width of the meander increases as the current speed increases the birth of the large meander state occurs as a consequence of the ocean spin do

the mid cenozoic succession and evolution of the mut basin southern turkey and its regional significance abstract the hitherto poorly known mut basin occupies a position that is critical to our understanding of the later cenozoic history of south central turkey the biostratigraphic and sedimentological study reported here reveals an extended and complex pattern of basin evolution and enables the history of this basin to be compared in detail with that of adjacent south turkish basins the oldest basin fill deposits are demonstrated to be oligocene to earliest miocene in age and comprise alluvial redbeds thick lacustrine deposits and thin lagoonal sediments mainly supplied from northern tauride sources this mainly terrestrial megasequence resulted from an early oligocene phase of crustal extension leading to rapid trap door subsidence and the formation of narrow e w trending troughs this phase was terminated by a minor marine incursion and through reactivation of basement faults during renewed extension in the earliest miocene the overlying miocene succession thus rests with local angular discordance upon tilted and gently deformed oligocene and older rocks subsequent subaerial erosion created an irregular pre burdigalian palaeotopography that strongly influenced the nature thickness and distribution of the early miocene basin fill in palaeotopographic depressions the miocene sequence commences with alluvial fan braidplain and meander belt redbeds formed in river systems that flowed mainly south and southeast these pass up and laterally into more extensive lagoonal and shallow marine mixed clastic carbonate units yielding late burdigalian to early langhian microfaunas marking the inception of the main miocene marine transgression in this area episodic northwards marine advance led to isolation of the northerly source of siliciclastic detritus and resulted in periodic onlap of mid to inner shelf fine grained carbonates with thin clastic intercalations that include isolated coralgal build ups calcarenite mounds and sand waves at the peak of miocene transgression mid serravallian thick reefal limestones were deposited far to the north and also formed on top of basement highs forming the southern and eastern flanks of the basin significant influxes of coarse and fine siliciclastics from the north attest to periodic progradational events that are more conspicuous and protracted in the late serravallian and tortonian however muddy deeper shelf conditions prevailed throughout the middle miocene in the central part of the basin while stronger currents and unstable slopes characterise the constricted marine strait in the southeast of the basin near silifke in terms of their sequential arrangement palaeoenvironmental and tectonic evolution the oligo miocene sediments of the mut basin closely resemble coeval sequences in the adjacent ecemis aktoprak and karsanti northern adana basins and share a similar history involving complex interplay between regional tectonics and eustasism deeper water oligo miocene sequences in the outboard troughs such as the southern adana basin and the kyrenia misis andirin complex yield more subtle signatures of these tectonic and eustatic events the differences between these basins are attributable to the influence of regional kinematic elements generated during the reorganisation of plate boundaries in the northeast mediterranean that followed final suturing of the arabian and anatolide plates in the mid cenozoic

evidence for 1 5 km of uplift of the central anatolian plateau s southern margin in the last 450 kyr and implications for its multiphased uplift history

late palaeogene neogene evolution of the triple junction region near maras south central turkey the marao region of turkey includes the anatolian arabian african triple junction the african arabian margin is marked by left lateral transtension along the dead sea kara su rift motion on the anatolian arabian boundary is partitioned between the left lateral east anatolian fault and a fold thrust belt termed the engizek zone equivalent to the bitlis suture further east the african anatolian boundary lies along the cyprus misis andirin trend and is expressed near the triple junction as the aslantao iskenderun zone now undergoing slow left lateral transtension the neogene evolution of these boundaries is largely recorded in the stratigraphy and structure of the basins that lie along the anatolian arabian lice basin and anatolian african aslantao iskenderun basin boundaries these basins appear to have developed in the early miocene along major strike slip zones large half graben in the pre neogene 9basement9 of the western misis andirin block developed contemporaneously with motion on the anatolian african boundary these extensional features evolved subsequent to the intense shattering of the mesozoic carbonate sequence in the misis andirin block and its mixing with panels of deep water palaeogene strata to form an extensionally disrupted assemblage transpression and conversion of both anatolian african and anatolian arabian boundaries to fold thrust belts occurred in the late miocene transpression continues along the anatolian arabian boundary but transtension has recurred along the anatolian african boundary since the pliocene

the behaviour of a multiple bar system in the nearshore zone of terschelling the netherlands 1965 1993 abstract the behaviour of a multiple bar system in the nearshore zone of the island of terschelling the netherlands is investigated on the time scale of years using a data set of soundings the data set covers the period from 1965 to 1993 the behaviour is analysed in terms of bar crest position and in terms of morphometric parameters such as bar crest depth height width and volume two or three breaker bars are permanently present in the study area each individual bar passes through three stages during its existence 1 generation close to the shore 2 seaward migration and 3 degeneration at the outer margin of the nearshore bar zone the key factor controlling the behaviour of the inner bars is the crest depth of the outer bar three different couplings between the behaviour of the individual bars have been observed 1 bar stage changes due to the degeneration of the outer bar 2 prevention of the transition of an inner bar from the first to the second stage caused by the appearance from alongshore of a new outer bar having a small crest depth and 3 difference in mean annual seaward migration rate caused by the possible presence of a more seaward positioned bar it is hypothesized that the crest depth of the outer bar governs the relative importance of processes inducing shoreward and seaward migration in the inner nearshore bar zone and therefore controls the behaviour of the nearshore bar zone on the time scale of years

mut basin turkey miocene carbonate depositional styles and mixed systems in an icehouse setting the mut basin in southcentral turkey contains a rich variety of cenozoic carbonate deposits that developed on a complex pre miocene topography and can be studied in seismic scale three dimensional outcrops these include open and rimmed carbonate shelves with steep slopes small isolated platforms and mixed carbonate siliciclastic systems showing reciprocal sedimentation the exceptional preservations of the stratal geometries make it possible to easily link large scale depositional geometry to depositional facies in a variety of platform types and depositional environments the mut basin provides a better understanding of 1 the control of antecedent topography on carbonate platform development 2 the influence of icehouse conditions e g high amplitude high frequency sea level fluctuations on the carbonate system 3 the link between faunal evolution and the style of carbonate platforms and stratigraphic architecture 4 lateral and reciprocal carbonate and siliciclastic sedimentation 5 platform asymmetry and local controls on stratal geometries and 6 the architecture of steep carbonate margin and associated gravitational collapse deposits these concepts are directly applicable to time equivalent cenozoic carbonate reservoir systems in southeast asia the southern caribbean and the eastern mediterranean

glacial eustasy during the cenozoic sequence stratigraphic implications a newly constructed composite oxygen isotope record is a proxy for eustasy that extends back to the cretaceous tertiary boundary and provides an independent test of sequence stratigraphic based eustatic curves the isotope record shows several eustatic episodes that are consistent with the geological record of ice sheet evolution the first evidence for the existence of an ice sheet in east antarctica occurs near the lower middle eocene boundary base of the lutetian stage there is no evidence for a large ice sheet on antarctica prior to this time however strata of this age are lacking over most of the continent the isotope curve also indicates that the ice sheet experienced phases of growth during the late eocene and middle oligocene followed by a decrease in volume in the early miocene the ross sea stratigraphic record indicates initial evolution of the west antarctica ice sheet during the early miocene by the middle miocene the ice sheet spread across the ross sea weddell sea and antarctic peninsula continental shelves the pliocene pleistocene record of glaciation in antarctica includes numerous glacial erosion surfaces on the continental shelf indicating repeated advance and retreat of both east and west antarctica ice sheets these volume changes in the antarctica ice sheet were in response to the rise and fall of sea level caused by expanding and contracting northern hemisphere ice sheets there is a reasonable correlation between eustatic curves derived from sequence stratigraphic studies and the composite oxygen isotope record since the middle eocene this correlation indicates that glacial eustasy has been the principal factor regulating stratal stacking patterns on a global scale since the middle eocene

tectonic controls on stratigraphic evolution of the adana basin turkey the neogene adana basin of se turkey was initiated after thrust emplacement of the tauride belt to the north of the basin seismic reflection profiles across the southern part of the adana basin provide information on structural and stratigraphic evolution of the basin based on seismic character and the identification of unconformities three megasequences and two mega sequence boundaries are identified the first megasequence is partly coincident with an early miocene rifting event and it comprises reefs that have grown on fault footwall crests with fore and back reef sediments in intervening lows subsequent rapid flexurally induced subsidence generated an underfilled basin which was then passively filled by turbiditic sediments megasequence 2 showing aggradational character on seismic profiles further extensional faulting and coupled sinistral wrench faulting took place after the deposition of megasequence 2 erosional truncation of its upper part is followed by the deposition of continental and shallow marine sediments of megasequence 3 which shows localized progradational sequences characteristic of shallow water deposition further minor extensional faulting took place after the deposition of megasequence 3

effects of antecedent topography on reefal carbonate deposition early middle miocene of the adana basin s turkey abstract early middle miocene reefal limestones and other shallow marine sedimentary sequences were important components of neogene basins especially the adana basin in southern turkey the most important controlling factors of sedimentation were antecedent topography and substratum type clastic input and sea level changes of different scales the effects of these factors can be observed on the southwest extension of the adana basin miocene sediments unconformably overlie the older limestones ophiolite and ophiolitic melange lithological variations and structural properties of pre miocene rocks caused an irregular sea floor topography development that was initially filled by local terrestrial conglomerates during the early miocene transgression these terrestrial clastics transitionally passed into shallow marine clastics and also new pebbly conglomerate sandstone bearing deposits observed in local depressions of pre miocene topography remaining low lying areas were filled by claystones and sandy clayey limestones at the same time reef limestone deposition developed over the higher areas where a hard substratum was available for red algae and other reef builders large shelled organisms in the clastics created a suitable substratum for successive reef level development the carbonate deposition shifted landwards due to continuous transgression intermediate sea level changes causing backstepping reef development small sea level changes in the study area controlled the energy of the environment lithological variations in the clastics and lateral facies changes in each reef body

elastic properties of continental carbonates from controlling factors to an applicable model for acoustic velocity predictions we have provided new insights into the controlling factors of elastic properties in continental carbonate rocks and introduced an applicable model for acoustic velocity predictions in such a medium petrophysical properties porosity permeability p and s wave velocities from laboratory measurements have been coupled with thin section observations and characterizations and x ray diffraction xrd analyses a major achievement is the establishment of the link between the mineralogical composition and the p and s wave velocity dispersion at a given porosity this reflects the subtle interplay between physico chemical and biological precipitation of continental carbonates which can also be associated with a strong influence of detrital mineralogical inputs the result is a mineralogical commixture coupled to a wide array of pore types inherited from the strong ability of carbonate rocks to undergo diagenetic alteration the proposed model takes into account the elastic moduli of the minerals porosity and pore shape and it is based on the effective medium theory we have considered the case in which the medium contained randomly oriented pores with different aspect ratios overall the fit between the predicted trends and the experimental data is fairly good especially for calcite and quartz matrix mineralogy the results are even better when considering mineralogy inferred from xrd data although in some case and despite the aspect ratio variation in both simulations the model fails to accurately predict the p wave velocities this probably means that another factor is at stake beside mineralogy this can be explained by the limitation of the effective medium approach which oversimplifies the reality and fails to account for the variability of some aspect ratio from one inclusion to another

tectonic and climatic controls on quaternary fluvial processes and river terrace formation in a mediterranean setting the goksu river southern turkey climate and tectonics effect the fluvial evolution of the mediterranean mut basin the basin contains a river terrace staircase of 16 levels t16 t1 ranging from 365 to 10a m above the current goksu river in its middle and lower sections these river terraces records tectonic uplift in the mut basin optically stimulated luminescence osl dating of the fluvial sediments of the youngest terrace t16 provides a chronology for the assessment of the important impacts of climatic changes the ages from the youngest river terrace deposits in t16 may be subdivided into two intervals 1 239 194 7 ka during the later part of marine oxygen isotope stage mis 7 implying that the aggradation of t16 started in the final phase of this warm period and 2 187 9 171 ka during much of mis 6 thus it appears that the goksu river continued depositing sediment from an interglacial into a glacial time the differences in climate driven fluvial evolution between this mediterranean fluvial system and the classical well studied temperate periglacial river systems in europe may be the result of different vegetation cover and greater thaw of more intense snowfalls 2018 university of washington published by cambridge university press

reef building and carbonate production modes in the west central tethys during the cenozoic abstract changing components rock textures lithofacies platform types and architecture throughout time are unique characteristics of carbonate rocks characterizing these attributes has been approached by 1 building reference models for specific phanerozoic intervals 2 recognizing the climatic impact in modulating carbonate production and 3 analyzing the influence of changing bio geochemical conditions the reference model approach is mostly based on biological evolution the climatic impact approach emphasizes temperature and the bio geochemical approach considers the changes in mg ca ratios and ca concentrations in the oceans to date however an analysis integrating all of these factors is still missing the analysis presented here includes all these factors but also co 2 which is fundamental for both photosynthesis and caco 3 precipitation here we analyze the waxing and waning of cenozoic reef limestones from the central tethys region through several steps 1 on the basis of rock volume rock textures associated sediments and light dependent skeletal components as records of light penetration and wave energy depth 2 on global environmental conditions 13 c 18 o p co 2 temperature and 3 on the basis of functionality nutritional requirements and available resources through the cenozoic water motion whether induced by surface or internal waves or by currents increased as the thermal gradients strengthened both with depth and with latitude active water motion is essential for plankton catchers such as corals but less so for many larger benthic foraminifers lbf pycnoclines in the meso oligophotic zone would then favor the benthic plankton catchers such as corals but would be detrimental for many lbf warm temperatures favored lbf the eocene lbf families predominated during lowering of atmospheric p co 2 by using respiratory co 2 to enhance the symbiont production of photosynthates under oligotrophic conditions and limited turbulence whereas the miocene families had to adapt to a progressive increase in turbulence the eurythermal coralline red algae however became preponderant producers in the mesophotic zone during times when the 13 c was relatively high this explains two apparent paradoxes 1 corals thrive best when the earth s high latitudes cool and 2 the dominance of corals and lbf is inversely correlated despite they both require tropical conditions and have similar trophic strategies mixotrophy

spectral signatures for swash on reflective intermediate and dissipative beaches in this paper we synthesise a large data set gathered from a wide variety of field deployments and integrate it with previously published results to identify the spectral signatures of swash from contrasting beach types the field data set includes the full range of micro tidal beach types reflective intermediate and dissipative with beach gradients ranging from approximately 1 6 to 1 60 exposed to offshore significant wave heights of 0 5 3 0 m the ratio of swash energy in the short wave f 0 05 hz to long wave f 0 05 hz frequency bands is found to be significantly different between the three beach types swash energy at short wave frequencies is dominant on reflective and intermediate beaches and swash at long wave frequencies is dominant on dissipative beaches consistent with previously reported spectral signatures for the surf zone on these beach types the available swash spectra were classified using an automated algorithm clara into five different classes the ordered classes represent an evolution in the spectrum shape described by a frequency downshifting of the energy peak from the short wave into the long wave frequency band and an increase in the long wave swash energy level compared to a relatively minor variation in the short wave swash energy level a universally common feature of spectra from all beach states was an f 4energy roll off in the short wave frequency band in contrast to the broadly uniform appearance of the short wave frequency band the appearance of the long wave frequency band was highly variable across the beach states we incorporate the results presented here and previously published observations into the morphodynamic beach state model and propose an ordered sequence of swash spectra under increasing and decreasing incident wave energy level this extension of the beach state model to include the swash zone leads to the following propositions for morphodynamic controls on the nature of the swash spectrum 1 the short wave part of the swash spectrum is relatively constant in form across all beach states f 4 energy roll off and the energy density per unit frequency is controlled by the beach face gradient alone 2 the spectral bandwidth of the energy roll off varies directly with offshore wave energy level and inversely with beach face gradient or beach state in a manner consistent with the non linear wave breaking criterion 3 the infragravity part of the swash spectrum is highly variable in form across all beach states and the energy level is related to the offshore wave energy level and surf zone morphology

bar formation due to wave groups and associated long waves abstract field observations reveal that waves propagating onto a beach from deeper water have a grouped structure associated with this pattern of alternating high and low waves is a long wave forced by radiation stress variations due to the changing short wave height as the wave groups propagate onshore the relationship between the variation in the short wave height and the long wave motion is complicated by breaking of the short waves reflection of the long wave and the generation of a free long wave by time variation of the breakpoint position nevertheless there may still be a fixed phase relation between the short wave envelope and the long wave motion at any particular location resulting in a net transport of sediment over the timescale of the short wave groups this transport arises from sediment grains mobilised by short waves and moved by the long wave motion model predictions of wave group propagation onto a beach and the associated long wave motions are presented which suggest that sediment transport due to short wave long wave coupling may result in the formation of a bar within the inner surf zone and the possibility of additional bars further offshore outside the surf zone this mechanism for bar formation may provide a new framework for understanding bar morphodynamics

tectono stratigraphic evolution of an early miocene incised valley fill derincay formation in the mut basin southern turkey abstract an early miocene early burdigalian incised valley fill was produced through development of an alluvial system during active extension and block rotation in the mut basin five phases of alluvial activity have been recognized and are linked to specific tectono stratigraphic factors the entrenchment phase phase 1 was a response to a rapid decrease in accommodation caused by a combination of sea level fall and accelerated tectonism that occurred around the basin during active extension a lacustrine depositional system that pre dated entrenchment was abruptly succeeded by an erosional fluvial system the initial erosion the entrenchment phase was followed by the deposition of ephemeral meandering fluvial facies and later by high sinuosity sandy meandering fluvial facies during the aggradational phase phase 2 coarser grained lower sinuosity meandering river facies were vertically stacked in response to successive periods of fault block rotation and basinal subsidence the thickest stratigraphic interval was deposited during this time simultaneously in a basinward position finer grained distal facies were deposited the succeeding backfilling phase phase 3 was marked by further fault block rotation and an increase in the catchment area that resulted in higher flow regime and more sediment input a further increase in accommodation space due to block rotation resulted in the retreat of facies belts and the deposition of a retrogradational stacked gravelly low sinuosity meandering facies during the early transgressive phase phase 4 in the downstream part of the alluvial valley fluvio deltaic and non marine transitional facies were deposited and progressively retreated landwards during marine flooding phase 5 marks the main interval of early miocene marine transgression a combination of global eustasy and regional epeiric subsidence during this time the facies belts within the incised valley fill were dominated by estuarine and lagoonal facies assemblages while the distal parts of the alluvial valley became completely flooded with marine waters at the end of the transgressive phase in the uppermost early burdigalian the estuarine and lagoonal facies migrated further inland while shallow marine sediments reefal limestones were deposited in distal parts of the now drowned valley blanketing the pre existing topography

a comparison of two early miocene carbonate margins the zhujiang carbonate platform subsurface south china sea and the pirin platform outcrop southern turkey early miocene carbonate platform complexes have been the subject of extensive exploration efforts in southeast asia for example the gunung putih carbonate complex east java sea and the zhujiang and liuhua platforms pearl river mouth basin however few outcrop equivalents of these early miocene platforms have been published to date in this study we present an outcrop that is an excellent analog for this petroleum province the pirin outcrop is an early miocene carbonate platform to basin transition exposed on the northern flank of the mut basin in southern turkey the carbonates were deposited during a time of relative tectonic quiescence in the early miocene burdigalian over a relict paleotopography inherited from oligocene tectonic activity the interval described here is interpreted to be influenced by three large relative sea level cycles with 100 150 m amplitude these generated a steep edged platform with prograding slope and margin geometries during the highstands whereas during the lowstands thin carbonate platforms developed with onlapping geometries against the older underlying slump deposits stratigraphic relationships indicate that collapse of the platform margin occurred during late highstand to early lowstand times and was coincident with major sea level falls during transgression an isolated platform complex developed carbonate production on these platforms shut down around the maximum flooding leading to terminal drowning this may have been the result of eutrophication caused by the arrival of nutrients from an encroaching deltaic system combined with a period of rapid relative sea level rise the subsurface zhujiang platform pearl river mouth basin china is an early miocene carbonate platform that developed along the flank of a basement high in the basin a steep prograding carbonate shelf margin developed with large scale slumping and collapse features in places pinnacles and small isolated platforms grow across a zone seaward of the margin a strikingly similar stratigraphic organization steep shelf margin slumps and isolated platforms is observed in the pirin outcrop these similarities are attributed to a common tectonostratigraphic setting the rapid marine flooding of a complex relict topography during a time of relative tectonic inactivity and a burdigalian eustatic sea level curve with cycles of sufficiently large amplitude to have a significant impact on the platform morphology at the exploration scale the outcrop allows us to test three play concepts from outcrop observations the slump packets play concept 1 do not seem to be sufficiently interconnected to make a viable prospect the development of an enhanced porosity wedge play concept 2 at the shelf margin will be testable with future outcrop studies in addition with future outcrop work a predictive model for the development of porosity in the isolated platforms can be developed play concept 3 to more successfully predict porosity prior to drilling at the reservoir scale observations of subseismic bedding patterns from the outcrop will help us construct more accurate reservoir models additionally outcrop observations of the dimensions of facies belts and their lateral and vertical variability will improve the way in which we populate a reservoir model with facies and reproduce variability on a scale finer than the interwell spacing

long wave forcing on a barred beach we present new laboratory data on long wave forcing over a barred beach profile under random wave breaking conditions the data include incident and radiated wave amplitudes wave set up and detailed measurements of the cross shore variation in long wave amplitude including shoreline swash amplitudes the total surf zone width was varied via changes in both wave height and the water level over the bar crest the data obtained from the barred beach are also compared with previous data obtained from a plane beach under essentially identical short wave forcing conditions the presence of the bar induces a frequency downshift in the spectral peak of the radiated long waves a consequence of the increased surf zone width on the barred beach and a clear signature of long wave forcing by a time varying breakpoint further comparisons of the two data sets suggest that the bar leads to resonant trapping and amplification or suppression of the shoreline motion at discrete long wave frequencies well defined standing long wave motion occurs at discrete frequencies inside the bar and the resonant response is consistent with a simple seiche between the bar crest and shoreline in agreement with previous numerical model studies the long wave structure offshore of the breakpoint depends on the relative positions of the bar shoreline and breakpoint and is inconsistent with a numerical solution for a free standing long wave over the barred beach profile

a numerical study of the kuroshio south of japan abstract a numerical model is used to study the interaction of the kuroshio with boundary constraints south of japan the model consists of two layers with the lower layer inert and is both nonlinear and quasi geostrophic the boundary constraints are highly idealized the kyushu peninsula and its adjacent continental shelf have the form of a v shaped wedge on an otherwise rectilinear coastline the izu ridge is represented as a square island solutions almost always form a meander downstream from kyushu the dynamics of meander formation involve the interaction of a rossby lee wave generated by the kyushu peninsula and a westward disturbance forced by the izu ridge three different quasi steady paths have been identified the first path has a meander between kyushu and the izu ridge passes to the north of the ridge and is associated with a current of low volume transport the second path has a large meander between kyushu and the izu ridge passes to the south of the izu ridge and always occurs when

waves long waves and nearshore morphology abstract recent field measurements on beaches of different slopes have established that wave motion at periods substantially longer than the incident waves dominates the velocity field close to the shore analysis of a number of extensive data sets shows that much of this long wave motion is in the form of progessive edge waves though forced wave motion standing edge waves and free waves propagating away from the shore may also contribute to the energy theoretically the drift velocities in bottom boundary layers due to edge waves show spatial patterns of convergence and divergence which may move sediment to form either regular crescentic or cuspate features when only one edge wave mode dominates or a bewildering array of bars bumps and holes when several phase locked modes exist together convincing field demonstration of the link between nearshore topography and edge waves only exists for the special case of small scale beach cusps on steep beaches formed by edge waves at the subharmonic twice the period of the incident waves at longer periods the link is proving more difficult to establish due to the longer time scales of topographic changes the interaction between pre existing topography and the water motion and the observation of broad banded edge wave motion which is not readily linked to topography with a well defined scale these ideas are however central to the study of nearshore processes as most of the plausible alternate hypotheses do not seem to lead to quantitative predictions clearly further theoretical and observational work is essential

multi phased uplift of the southern margin of the central anatolian plateau turkey a record of tectonic and upper mantle processes abstract uplifted neogene marine sediments and quaternary fluvial terraces in the mut basin southern turkey reveal a detailed history of surface uplift along the southern margin of the central anatolian plateau from the late miocene to the present new surface exposure ages 10be 26al and 21ne of gravels capping fluvial strath terraces located between 28 and 135 m above the goksu river in the mut basin yield ages ranging from ca 25 to 130 ka corresponding to an average incision rate of 0 52 to 0 67 mm yr published biostratigraphic data combined with new interpretations of the fossil assemblages from uplifted marine sediments reveal average uplift rates of 0 25 to 0 37 mm yr since late miocene time starting between 8 and 5 45 ma and 0 72 to 0 74 mm yr after 1 66 to 1 62 ma together with the terrace abandonment ages the data imply 0 6 to 0 7 mm yr uplift rates from 1 6 ma to the present the different post late miocene and post 1 6 ma uplift rates can imply increasing uplift rates through time or multi phased uplift with slow uplift or subsidence in between longitudinal profiles of rivers in the upper catchment of the mut and ermenek basins show no apparent lithologic or fault control on some knickpoints that occur at 1 2 to 1 5 km elevation implying a transient response to a change in uplift rates projections of graded upper relict channel segments to the modern outlet together with constraints from uplifted marine sediments show that a slower incision uplift rate of 0 1 to 0 2 mm yr preceded the 0 7 mm yr uplift rate the river morphology and profile projections therefore reflect multi phased uplift of the plateau margin rather than steadily increasing uplift rates multi phased uplift can be explained by lithospheric slab break off and possibly also the arrival of the eratosthenes seamount at the collision zone south of cyprus

paleomagnetic implications on the evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we first re examined the apparent polar wander curves for stable eurasia and africa since the triassic these curves were then combined together with curves of north and south america according to the kinematics of the atlantic ocean and a synthetic polar wander curve was given then most of the paleomagnetic results from the tethys mobile belt from the atlantic to the pamirs were analysed several groups of plates microplates and blocks can be seen first relatively stable regions like maghreb and sicily which have not moved much then we have a group formed by iberia sardinia italy and to a lesser extent corsica and the western and central alps for these blocks movements are anticlockwise rotations chiefly driven by the anticlockwise rotation of africa but they are sometimes stronger to the east a major change takes place the north of the aegean sea and the ionian zone are clockwise rotated and these rotations are recent oligocene miocene for the first part pliocene to the present for the second part a major problem arises in turkey caucasus and iran paleomagnetic results indicate a position far to the south of eurasia and at the same time geological evidence is in favour of a position close to eurasia we discuss these discrepancies

high frequency doppler radar measurements of the florida current in summer 1983 an oceanographic evaluation is carried out here of high frequency hf doppler radar measurements of surface currents made by the noaa wave propagation laboratory june 26 to august 4 1983 at the western side of the florida straits in the area between jupiter and west palm beach in the context of the subtropical atlantic climate studies these current measurements are compared with direct current measurements made at various positions in the area covered by the radar and investigated for their potential as transport indicator means and standard deviations of the downstream current component compared well with those from pegasus and subsurface moored current measurements carried out in the northern part of the radar current field up to 35 km distance from the coast but there seemed to exist a bias in the southern part of the current field measured by the radar causing significant northward mean shear about 20 km offshore low frequency current fluctuations from the radar currents and near surface moored currents were coherent for the downstream but not the small cross stream component mean downstream components in a center strip of the radar current field where data quality was found to be best were compared with florida current transports as determined by cable and by moored current measurements but transport fluctuations were small during the measurement period which fell into the summer maximum of the florida current coherence with cable transports was significant at the meander time scale of 5 days but a longer period transport burst of 3 106 m3 s occurring during the time period was not identified in the surface current measurements in summary the hf radar as used in this application is useful to determine near surface patterns of eddies and meanders but doubtful for derived quantities like energy fluxes and vorticity without additional calibration

gulf stream fluctuations and meanders over the onslow bay upper continental slope abstract gulf stream fluctuations observed over the 200 and 400 m isobaths off onslow bay north carolina have a prominent weekly time scale the principal fluctuations observed during the 4 month winter experiment are consistent with webster s 1961a description of downstream propagating skewed lateral meanders of the gulf stream over the upper continental slope the subtidal velocity fluctuations were highly coherent over the vertical extent 120 m and over the horizontal extent 64 km of our array the implied downstream propagation speed was 30 km day 1 for the weekly period meanders concurrent satellite images of a sea surface temperature sst meander pattern indicate that subsurface temperature salinity velocity and relative vorticity maxima occurred as meander crests shoreward sst front excursions passed over the experiment site the meandering currents were not coherent with nearby wind stress or coastal sea level fluctuations eddy flux estimates indicate energy conversion from the f

bar trapped edge waves and longshore currents edge waves react to the presence of a mean longshore current as though the current was a change in bottom topography in this way the cross shore shape of the edge wave can be amplified over the current relative to the shoreline in the same way as the edge wave shape can be amplified over bars on a beach with both longshore currents and bars the degree of edge wave amplification or trapping depends on the strength and location of the longshore current shear relative to the steepness of the bottom slope and also on the direction of edge wave propagation relative to the longshore current weak longshore current shear over well developed bars does not significantly alter edge wave trapping over bars simply enhancing or reducing the existing bar trapping effect conversely strong current shears over gentle topography can govern the existence and location of edge wave trapping the extreme example being edge wave trapping on plane beaches where the amplification is entirely due to the existence of mean longshore currents in reality the possibilities are restricted since the shape of the longshore current profile is primarily determined by the pattern of incident wave breaking which itself depends on the beach profile the importance of realistic current shear relative to realistic bottom slope in determining edge wave shape is demonstrated using frequency wavenumber spectra taken during the duck experiment on low frequency and incident band longshore and across shore hydrodynamics delilah at duck north carolina these frequency wavenumber spectra show a general dominance of edge waves traveling with the longshore current in cases where the current shear is strong relative to the bottom slope the location of edge wave trapping changes as the longshore current profile changes with the tide when the bar was well defined the longshore current shear was rarely strong enough to influence the existence or location of edge wave trapping but could have a enhancing effect while past work i e schonfeldt 1995 has suggested that edge waves trapped and amplified on longshore currents may cause bars to form on plane beaches and bars to move on barred beaches these observations suggest that under most conditions edge wave trapping on longshore currents is a subtle effect modulated by sea level changes and is unlikely to produce significant morphological change unless the current is very strong

gulf stream kinematics along an isopycnal float trajectory abstract an isopycnal following float was deployed near the 400 m depth level in the high speed jet region of the gulf stream and tracked for approximately 300 km from the blake plateau towards cape hatteras during 16 19 may 1983 during its transit through a 400 change in bottom depth the layer tagged by the float was surveyed with xbts and hydrostations and the surface mesoscale structure was determined from noaa 6 7 and 8 ir imagery these data provide the first three dimensional observations of water parcel motion along a gulf stream trajectory in the upper main thermocline approaching path segments with anticyclonic curvature flow in the surrounding stream volume was divergent and vertically compressed approaching path segments with cyclonic curvature the flow in the surrounding stream volume was divergent and vertically compressed approaching path segments with cyclonic curvature the flow in the surrounding steam volume was convergent and vertically stretched the float was upwelled approa

kinematic evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we present an updated series of kinematic reconstructions of the major plates around the tethys from the atlantic ocean to the pamirs between the early jurassic and the present this set is used elsewhere as a basis for paleogeographic maps of the entire region the problems related to the positions of the continents in the lower triassic are also discussed no direct analyses of magnetic anomalies and fracture zones in the atlantic have been made rather all available poles and rotations have been tested in order to eliminate or minimize possible kinematic errors the reconstructions are shown for nine key geological periods which correspond to well recognized magnetic anomalies except for the jurassic cretaceous boundary and the cretaceous tertiary boundary which correspond to interpolated positions paleolatitudes have been drawn using the study of westphal et al 1986 an attempt has been made to take into account the displacements caused by formation of the continental margins and basins by stretching the resulting relative vector of motions along the northern boundary of the tethys shows a significant change 80 m y ago left lateral motion with compression dominates before whereas right lateral motion with compression dominates after to the east rates of motion vary by a factor of three with time and four maxima can be clearly related to tectonic events in the late jurassic late cretaceous eocene and post middle miocene to the west north of apulia on the contrary the motion rate has not changed significantly since the early cretaceous and is close to 1 cm yr as an average these rather complex adjustments in rates and directions of relative motion are produced in great part through a complex migration of the africa eurasia pole of rotation and seem to be mostly governed by the tectonics of the tethys plate boundary

modification of edge waves by barred beach topography a numerical model to calculate edge wave profiles and wavelengths for arbitrary bottom profiles and given frequency was developed utilizing the model wave equation of berkhoff 1972 following smith and sprinks 1975 surface profiles and longshore wave numbers were found for fixed wave periods using an eigenvalue approach the model was verified by calculating profiles and dispersion for a plane beach of mild slope and comparing results with the analytic solution of eckart 1951 and ursell 1952 the model was then applied to the case of a beach with multiple offshore bars with bar positions determined by the antinodal positions of a standing incident wave of a set frequency calculation of surface profiles for a range of frequencies using a fixed beach indicated that antinodes of the edgewave profiles tend to be trapped by the bars suggesting the possibility that bars affect the long wave climate in such a way as to lead to self maintenance over extended periods no effect of the bars on the dispersion relationship was found and it was concluded that for the particular beach profile used the edge waves respond to the mean beach slope over the offshore length of the profile

generation accumulation and resource potential of biogenic gas biogenic gas is generated at low temperatures by decomposition of organic matter by anaerobic microorganisms more than 20 of the world s discovered gas reserves are of biogenic origin a higher percentage of gases of predominantly biogenic origin will be discovered in the future biogenic gas is an important target for exploration because it occurs in geologically predictable circumstances and in areally widespread large quantities at shallow depths in rapidly accumulating marine sediments a succession of microbial ecosystems leads to the generation of biogenic gas after oxygen is consumed by aerobic respiration sulfate reduction becomes the dominant form of respiration methane generation and accumulation become dominant only after sulfate in sediment pore water is depleted the most important mechanism of methane generation in marine sediments is the reduction of co2 by hydrogen electrons produced by the anaerobic oxidation of organic matter co2 is the product of either metabolic decarboxylation or chemical decarboxylation at slightly higher temperatures the factors that control the level of methane production after sediment burial are anoxic environment sulfate deficient environment low temperatu e availability of organic matter and sufficient space the timing of these factors is such that most biogenic gas is generated prior to burial depths of 1 000 m in marine sediments most of the biogenic gas formed can be retained in solution in the interstitial pore waters because of higher methane solubility at the higher hydrostatic pressures due to the weight of the overlying water column under certain conditions of high pressures and or low temperatures biogenic methane combines with water to form gas hydrates biogenic gas usually can be distinguished from thermogenic gas by chemical and isotopic analyses the hydrocarbon fraction of biogenic gas consists predominantly of methane the presence of as much as 2 of heavier hydrocarbons can be attributed to admixture of minor thermogenic gas due to low temperature degradation of organic matter the amounts of hydrocarbon components other than methane generally are proportional to temperature age and organic matter content of the sediments biogenic methane is enriched in the light isotope 12c dgr13c1 lighter than 55 ppt owing to kinetic isotope fractionation by methanogens the variations in isotopic composition of biogenic methane are controlled primarily by dgr13c of the original co2 substrate which reflects the net isotopic effect of both addition and removal of co2 the methane isotopic composition also can be affected by mixing of isotopically heavier thermogenic gas the possible complicating factors require that geologic chemical and isotopic evidence be considered in attempts to interpret the origin of gas accumulations accumulations of biogenic gas have been discovered in canada germany italy japan trinidad the united states and ussr in cretaceous and younger rocks at less than 3 350 m of burial and in marine and nonmarine rocks other gas accumulations of biogenic origin have undoubtedly been discovered however data that permit their recognition are not available

widespread miocene deep sea hiatuses coincidence with periods of global cooling high resolution biostratigraphic analyses of miocene deep sea cores reveal eight intervals of widespread hiatuses in the world ocean at 23 0 22 5 20 0 18 0 16 0 15 0 13 5 12 5 12 0 11 0 10 0 9 0 7 5 6 2 and 5 2 4 7 m y ago in complete sections these hiatuses correspond to intervals of cool faunal and floral assemblages rapid enrichment of 18 o and sea level regressions these factors suggest that miocene deep sea hiatuses result from an increased intensity of circulation and corrosiveness of bottom currents during periods of increased polar refrigeration

infragravity waves and nearshore bars in protected storm dominated coastal environments abstract field measurements of run up oscillations were conducted on fetch restricted storm wave dominated beaches in denmark experiments took place under conditions with breaker heights of 1 5 3 m and wave periods of 5 7 s statistically significant spectral peaks were identified in the infragravity regime the frequencies of these peaks were compared to frequencies predicted by the edge wave cut off model originally proposed by huntley j geophys res 81 1976 and it was found that the waves were probably cut off mode edge waves with the mode number corresponding to the number of nearshore bars at the locality in question the waves were usually standing alongshore but during an experiment in which a very high energy level prevailed the edge waves were probably progressive the selection of only one or two cut off modes may be the result of an interrelationship between the topographic cut off and offshore wave groups the nearshore region was surveyed following storms it was found that there was generally a good correlation between bar positions and rhythmic dimensions and the theoretical cross shore and longshore structure of the recorded edge waves it is concluded that infragravity waves may be important in the formation migration and morphology of nearshore bars with the number of bars depending on the edge wave mode number

topographic controls on production and deposition of tidal cool water carbonates uzes basin se france we document an example of a cool water carbonate deposit interpreted as a flood tidal delta formed during sea level fall in the uzes basin french miocene foreland basin in the miocene it was a peripheral basin connected to the open sea by a narrow 15 km long seaway the studied uzes formation is a 50 m thick tidal bioclastic carbonate body formed at the junction between the uzes basin and the seaway it is composed dominantly of rhodalgal packstones that are interpreted to have been produced inside the basin however most of the deposit was built out by bidirectional hydraulic dunes suggesting that accumulation of carbonate grains was not controlled by production but rather by tidal currents the deposit is thickest and coarsest grained and exhibits the larger dunes at the inlet of the seaway where currents are expected to have been fastest the deposit is thinner finer grained and more bioturbated away from the inlet toward the basin that is interpreted as a result of a decrease of current velocity due to flow expansion the main deposit exhibits a general upward increase in thickness and grain size of cross beds together with a decrease of faunal diversity from bivalve rich to rhodalgal facies consistent with progressive tidal flow acceleration in the seaway resulting from sea level fall lime mud is pervasive in the matrix of even the highest energy facies this suggests that one cannot draw any average correlation between permeability and architecture of the deposit also this could favor the observed early marine diagenesis of the deposit and give it a high preservation potential in the stratigraphic record

changing transport and curvature bias a new type of meandering in the florida straits meanders in strong inertial flows are generally asymmetric florida current meanders with periods of 7 10 days and flows that tend to meander offshore when strong and onshore when weak which we call type a have been widely documented we find a countertrend in the florida current data collected under the aegis of subtropical atlantic climate studies a type b meandering where flows tend to meander offshore when weak and onshore when strong on time scales of several months and depending on the strength of the flow the tendency displays a largely one sided preference for either the onshore or the offshore component of the meander in particular the data reveal a negative curvature bias during the generally higher transports in spring and summer when most of the speed cores were inshore and a positive curvature bias during lower transports in fall and winter when most speed cores were offshore the data show that any use of cross channel sea level slope to estimate the transport would generally overestimate the weaker but underestimate the stronger flows type b meander is interpreted as one of three types embodied in a meandering equation in which curvature changes are controlled primarily by the coriolis effect of downstream acceleration and hence by that of changing transport in this light the bimodal paths of the kuroshio south of japan is a type b meander

forearc high uplift by lower crustal flow during growth of the cyprus anatolian margin abstract we present a model for the dynamic formation of the forearc high of southern anatolia where sedimentation in the forearc basin leads to thermally activated deformation in the lower crust our thermo mechanical models demonstrate that forearc sedimentation increases the temperature of the underlying crust by blanketing the heat flux and increasing moho depth deformation switches from frictional to viscous with a higher strain rate led by increased temperature viscous deformation changes large wavelength subsidence into coeval short wavelength uplift and subsidence models show that forearc highs are intrinsic to accretionary wedges and can grow dynamically and non linearly at rates dependent on sediment accretion sedimentation and temperature the mechanism explains the uplift of the southern margin of the central anatolian plateau and the neogene vertical motions and upper plate strain in the anatolian margin along central cyprus this system is analogous to forearc highs in other mature accretionary margins like cascadia lesser antilles or makran

comparison of surface currents measured by hf doppler radar in the western florida straits during november 1983 to january 1984 and florida current transports an evaluation of surface currents measured by hf radar during november 29 1983 to january 31 1984 with radar sites at jupiter and stuart on the florida east coast is carried out in comparison with currents and transports measured by moorings and submarine cable while an earlier analysis of currents measured in summer 1983 with radars located at palm beach and jupiter schott et al 1985 found significant northward shear in the northward radar currents about 20 km offshore leading to concerns about a possible bias in the radar currents this effect was not observed in the second application farther north it is possible that the shear in the summer 1983 field might have been real and related to the topography in the southern part of the 1983 radar field where no intercomparison current data had been available concerning the usefulness of radar currents as florida current transport indicators which was the prime intention of their application in the context of the subtropical atlantic climate studies this second study finds much more encouraging results than the one based on the observations of summer 1983 while the first study was inconclusive because only small transport fluctuations occurred during the summer 1983 observation period this second study finds significant correlation florida current transport fluctuations had a total range of 15 106 m3 s during the second observation period and correlation with downstream radar currents averaged zonally across the center of the radar field was 0 85 coherence was significant for periods longer than 5 days highest correlation with transport was found for radar currents farthest out to the right of the axis of the stream

siliciclastic influx and burial of the cenozoic carbonate system in the gulf of papua abstract an extensive carbonate system in the gulf of papua gop developed in the late oligocene middle miocene was buried by huge influx of siliciclastics originated from papua new guinea major episodes of siliciclastic influx in the carbonate system are related to tectonic activity in the fold and thrust belt during the oligocene peninsular orogeny late miocene central range orogeny and late pliocene renewed uplift and exhumation of peninsular region siliciclastics did not influence the carbonate deposition during the late oligocene middle miocene since they were accumulated in the aure trough proximal foreland basin protecting the carbonate system the most significant burial of the carbonate system started during the late miocene early pliocene in the result of the central range orogeny however the largest influx was related to the renewed uplift of the papuan peninsula during the early late pliocene the shelf edge prograded 150 km and formed more than 80 of the modern shelf this high siliciclastic influx was also enhanced by the mid pliocene global warmth period and intensified east asian monsoons at 3 6 2 9 ma although many publications exist on carbonate siliciclastic mixing in different depositional environments this study helps understand the carbonate siliciclastic interactions in space and time especially at basinal scale and during different intervals of the carbonate system burial by siliciclastic sediments