significant sink of ocean eddy energy near western boundaries ocean eddies generated through instability of the mean flow are a vital component of the energy budget of the global ocean modelling combined with satellite altimetry data suggests that the energy from westward propagating eddies is scattered and eventually dispersed when they reach the western boundary of an ocean basin

an ice ocean coupled model an ice model an ocean model and a method of coupling the models are described the ice model is a synthesis with variations and extensions of previous modeling ideas ice thickness concentration velocity and internal energy are prognostic variables the ice thermodynamics are represented by temperatures at the snow surface ice surface the interior and the bottom surface melting and freezing rates are calculated at the ice atmosphere ice ocean and atmosphere ocean interfaces a prescribed portion of summer meltwater can be stored on the surface and refrozen in the fall the ocean model includes a second moment turbulence closure submodel and enables one to solve for oceanic heat flux the interfacial stress and subsurface properties in this paper the model is applied to one dimensional simulations but the equations are cited in a form for implementation by two and three dimensional models in a companion paper kantha and mellor this issue the model is used for two dimensional vertical plane simulations in the bering sea several one dimensional sensitivity studies are performed in the case where the ice model is decoupled from the ocean here the oceanic heat flux and sea surface temperature are prescribed constants the studies reveal the role and sensitivity of surface trapped meltwater ice concentration and ice divergence with the coupled ice ocean model the seasonally varying oceanic heat flux and mixed layer properties are determined by the model some comparisons with observations in the central arctic ocean are possible the role of the molecular sublayer immediately adjacent to the ice is examined frazi ice production is related to the large disparity in the molecular diffusivities for temperature and salinity the mixed layer model contains empirical constants which are known from turbulence data the molecular sublayer parameterization requires one empirical parameter b which is uncertain but from this study is assuredly greater than zero the value implicit in previous models the ice model requires the empirical parameters ci f and ci u to quantitatively account for freezing or melting processes in open leads their values are also uncertain but we present reasoning and sensitivity studies to suggest specific values finally an empirical parameter g is introduced it is the ratio of the value of the ice thickness used to represent average ice volume in the dynamic and thermodynamic equations to the value of the thickness needed in the heat conduction equation estimates of g are made from observed thickness distribution functions sensitivity studies show it to be an important parameter

depositional relations of cretaceous and lower tertiary rocks northeastern alaska analysis of depositional environments new paleontologic data and analogy with depositional patterns observed in areas to the west all indicate the need for revision of cretaceous and lower tertiary stratigraphy in northeastern alaska in the sadlerochit mountains area of the arctic national wildlife refuge the northern derived ellesmerian late neocomian kemik sandstone member and organic rich pebble shale member of the kongakut formation unconformably overlie jurassic and triassic rocks the unconformity which is of mid neocomian age is present throughout northernmost alaska and passes southward into a conformable shelf sequence after pebble shale deposition the depositional pattern is simply one of progradational basin filling from a southern brookian provena ce this pattern is represented in vertical sequence initially by deep marine basinal deposits succeeded by prodelta slope shales and ultimately by deltaic deposits that prograded to the east or northeast in a predictable fashion over most of the area the better known thick shallow marine and nonmarine units in the central north slope grade to thin prodelta or basinal turbidites some units are entirely missing owing to nondeposition on the south dipping flank of the basin no evidence exists for subaerial erosion to explain these marked stratigraphic changes in the sadlerochit mountains area which may be an extension of the barrow arch the pebble shale neocomian is overlain by about 1 600 ft 500 m of deep water deposits of late cretaceous age aptian and albian rocks are either absent by nondeposition or are represented by a thin condensed section here the upper cretaceous to lower tertiary section consists of basinal shale bentonite and thin bedded prodelta turbidites two noteworthy features in this sequence are an interval of organic rich shale of probable turonian to coniacian age just above the pebble shale and the placement of the cretaceous tertiary boundary within deep marine deposits unlike the western part of the north slope where deltaic deposition occurred in the early cretaceous prograding deltaic deposition d d not reach the western part of the wildlife refuge until early in the tertiary the consistent pattern of easterly deltaic progradation is complicated at igilatvik sabbath creek in the north central wildlife refuge by the occurrence of thick regressive dominantly nonmarine deposits of early tertiary age which apparently prograded into the basin from the south or southeast

devonian mississippian sinistral transcurrent faulting along the cratonic margin of western north america a hypothesis in the northern canadian cordillera three major proterozoic assemblages show a distinct sinistral separation along the long lived richardson hess fault zone it is suggested that this separation resulted from displacements along a mid paleozoic sinistral fault system connecting the devonian mississippian ellesmerian orogen of the arctic with the antler orogen of the western united states composite displacement of possibly hundreds of kilometres along this fault system created transpressional and transtensional deformation along the western outer margin of the north american craton deformation was accompanied by eastward progradation of turbiditic chert quartz arenites local igneous activity and exhalative ore deposition extensive late mesozoic and cenozoic compression and extension probably greatly modified mid paleozoic fault related deformation patterns

observations of overturning in the thermocline the context of ocean mixing abstract the time sequence of events that lead to internal wave breaking and ocean turbulence is investigated data are obtained from depths 100 400 m with a repeat profiling ctd and a coded pulse doppler sonar the instruments were deployed from r p flip during february march 1995 while stationed 30 km west of point arguello california as an aspect of the marine boundary layer experiment although the water depth at the site is 1500 m both rms shear and diapycnal diffusivity as inferred from the average rate and size of overturning events increase with depth below 250 m a deep source of wave energy is implied depth time series of 6 4 m shear s 2 m strain n2 n2 where n is the buoyancy frequency 6 4 m gradient richardson number ri n2 s2 and 2 m effective strain rate the depth derivative of ctd inferred vertical velocity are obtained at 4 minute intervals over a 9 day 100 400 m domain the occurrence of overturns static instabilities of vertical scale 2 m in the observed density

marine seismic refraction study between cape simpson and prudhoe bay alaska a marine seismic refraction study conducted between cape simpson and prudhoe bay alaska provides data for subsurface structural and geological cross sections of the western beaufort shelf the results suggest that the western beaufort shelf is underlain by a sedimentary prism with beds dipping and prograding to the northeast correlation of the refraction data with wells drilled on land and offshore reflection profiles permits tentative identification of geologic sequences on the basis of their seismic velocity this study associates near surface velocities of 1 60 1 65 km s with quaternary sediments and 1 82 2 35 km s velocities with tertiary strata velocities of 1 60 3 40 km s are correlated to upper cretaceous rocks 2 10 4 14 km s to lower cretaceous beds 5 66 5 68 km s to mississippian pennsylvanian carbonates and 4 24 6 08 km s to the franklinian basement composed of argillites and phyllites west of cape halkett the sedimentary section is mainly lower cretaceous whereas east of cape halkett upper cretaceous and tertiary strata dominate higher velocities 6 40 7 07 km s are thought to represent the crystalline basement probably silicic in composition although no seismic velocities typical of the upper mantle are present on the record sections a minimum depth calculation places the mohorovicic discontinuity no shallower than 20 km the interpretation indicates that the stratigraphic sequence present onshore at prudhoe continues to the offshore and implies that the western beaufort shelf may be a good prospect for oil the structures derived from seismic data indicate that the beaufort continental margin is not different from atlantic type margins and add further evidence to the concept of a rifted and rotated beaufort continental margin

north slope alaska source rock distribution richness thermal maturity and petroleum charge four key marine petroleum source rock units were identified characterized and mapped in the subsurface to better understand the origin and distribution of petroleum on the north slope of alaska these marine source rocks from oldest to youngest include four intervals 1 middle upper triassic shublik formation 2 basal condensed section in the jurassic lower cretaceous kingak shale 3 cretaceous pebble shale unit and 4 cretaceous hue shale well logs for more than 60 wells and total organic carbon toc and rock eval pyrolysis analyses for 1183 samples in 125 well penetrations of the source rocks were used to map the present day thickness of each source rock and the quantity toc quality hydrogen index and thermal maturity tmax of the organic matter based on assumptions related to carbon mass balance and regional distributions of toc the present day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original toc toco and the original hydrogen index hio prior to thermal maturation the quantity and quality of oil prone organic matter in shublik formation source rock generally exceeded that of the other units prior to thermal maturation commonly toco 4 wt and hio 600 mg hydrocarbon g toc although all are likely sources for at least some petroleum on the north slope we used rock eval and hydrous pyrolysis methods to calculate expulsion factors and petroleum charge for each of the four source rocks in the study area without attempting to identify the correct methods we conclude that calculations based on rock eval pyrolysis overestimate expulsion factors and petroleum charge because low pressure and rapid removal of thermally cracked products by the carrier gas retards cross linking and pyrobitumen formation that is otherwise favored by natural burial maturation expulsion factors and petroleum charge based on hydrous pyrolysis may also be high compared to nature for a similar reason

intraplate stresses and dynamical aspects of rifted basins abstract intraplate stresses play a important role during the syn and post rift evolution of sedimentary basins deviations from long term thermal patterns of post rift subsidence as well as the development of unconformities within rifted basins reflect to a large extent the temporal fluctuations of the regional stress fields in the lithosphere it appears that incorporation of intraplate stresses in dynamical models for basin development together with a quantification of the role of petrological changes in the crust lithosphere system can explain some of the observed shortcomings of thermal models of post rift basin subsidence late neogene accelerations in tectonic subsidence in the deeper parts of rifted basins in the northern atlantic and mediterranean regions could reflect a change in the level of intraplate stress over large areas of the globe non thermal contributions to the subsidence record affect estimates of crustal extension and consequently influence the depth at which hydrocarbon source rocks enter the maturity window stress induced changes in basement topography have also important consequences for the budget of fluid flow in the deeper parts of the sediment fill of the rifted basins as well as on the dynamics of diapirism

convectively driven mixing in the bottom boundary layer closely spaced vertical profiles through the bottom boundary layer over a sloping continental shelf during relaxation from coastal upwelling reveal structure that is consistent with convectively driven mixing parcels of fluid were observed adjacent to the bottom that were warm by several millikelvin relative to fluid immediately above on average the vertical gradient of potential temperature in the superadiabatic statically unstable bottom layer was found to be 21 7 3 1024 km 21 or 6 0 3 1025 kg m24 in potential density turbulent dissipation rates increased toward the bottom but were relatively constant over the dimensionless depth range 0 4 1 0z d where d is the mixed layer height the rayleigh number ra associated with buoyancy anomalies in the bottom mixed layer is estimated to be approximately 1011 much larger than the value of approximately 10 3 required to initiate convection in simple laboratory or numerical experiments an evaluation of the data in which the bottom boundary layer was unstably stratified indicates that the greater the buoyancy anomaly is the greater the turbulent dissipation rate in the neutral layer away from the bottom will be the vertical structures of averaged profiles of potential density potential temperature and turbulent dissipation rate versus nondimensional depth are similar to their distinctive structure in the upper ocean during convection nearby moored observations indicate that periods of static instability near the bottom follow events of northward flow and local fluid warming by lateral advection the rate of local fluid warming is consistent with several estimates of offshore buoyancy transport near the bottom it is suggested that the concentration of offshore ekman transport near the bottom of the ekman layer when the flow atop the layer is northward can provide the differential transport of buoyant bottom fluid when the density in the bottom boundary layer decreases up the slope

ice seawater turbulent boundary layer interaction with melting or freezing abstract a second moment turbulence closure model is applied to the problem of the dynamic and thermodynamic interaction of sea ice and the ocean surface mixed layer in the case of ice moving over a warm ocean surface layer melting is intrinsically a transient process that is melting is rapid when warm surface water initially contacts the ice then the process slows when surface water is insulated from deeper water due to the stabilizing effect of the melt water and the thermal energy stored in the surface layer is depleted effectively the same process prevails when ocean surface water flows under stationary ice in which case after an initial rapid increase the melting process decreases with downstream distance accompanying the stabilizing effect of the melt water is a reduction in the ice seawater interfacial shear stress this process and model simulators are used to explain field observations wherein ice near the marginal ice zone diverges from the main pack when the surface ice layer is m

estimates of the temperature flux temperature gradient relation above a sea floor the relation between the ux of temperature or buoyancy the verti cal temperature gradient and the height above the bottom is investigatedin an oceanographic context using high resolution temperature measure ments the model for the evolution of a strati ed layer by balmforthet al 1998 is reviewed and adapted to the case of a turbulent owabove a wall model predictions are compared to the average observa tional estimates of the ux exploiting a ux estimation method proposedby winters d asaro 1996 this estimation method enables the dis entanglement of the dependence of the average ux on the height abovethe bottom and on the background temperature gradient the classicaln shaped ux gradient relation is found in the observations model andobservations show similar qualitative behaviour despite the strong sim pli cations used in the model the results shed light on the modulationof the temperature ux by the presence of the boundary and support theidea of a turbulent ux following a mixing length argument in a strati edow furthermore the results support the use of thorpe scales close to aboundary if su cient averaging is performed suggesting that the thorpescales are a ected by the boundary in a similar way as the mixing length

mesozoic stratigraphy of canadian arctic archipelago and implications for opening of amerasian basin abstract mesozoic strata in the canadian arctic archipelago occur mainly in the sverdrup basin where the succession is up to 9 km thick the strata consist of alternating sandstone dominant units and argillaceous intervals and record 25 regional transgressions and regressions these resulted from the interplay of sedimentation tectonics and eustatic sea level changes subaerial unconformities occur on the basin margins and disappear basinward most of these unconformities are interpreted to be the product of eustatic sea level fall on the basis of correlation with global sea level charts however unconformities of latest aalenian late callovian hauterivian and coniacian ages are interpreted to be related to tectonic activity and the formation of the amerasian basin normal faulting and basic dike and sill intrusion occurred in the sverdrup basin from middle jurassic to early late cretaceous the latest aalenian and late callovian unconformities probably reflect early rifting events hauterivian uplift was widespread and coincides with the final phase of rifting and initiation of sea floor spreading in the amerasian basin marine onlap across the breakup unconformity began in barremian time and by albian much of the arctic archipelago had been transgressed basalt flows are intercalated with barremian to turonian strata in the northeastern sverdrup basin and represent the cratonward extension of the alpha mendeleyev volcanic ridge which was active during the opening of the amerasian basin coniacian uplift coincided with the cessation of volcanism in the sverdrup basin and of sea floor spreading in the ocean basin to the north end of article last page 253

plate reorganization a cause of rapid late neogene subsidence and sedimentation around the north atlantic subsidence analysis of wells in the central north sea and labrador grand banks and oft the west greenland scotian shelf and united states atlantic margin shows distinct quantitative stratigraphic correlation patterns of circum north atlantic sites a significant departure from the overall decrease in subsidence for the pliocene occurs in many wells when the rate is found to have increased one or more orders of magnitude from oligocence miocene rates wells were selected along transects from shore to basin to find if relative basin position is influenced by differential basin subsidence although stratigraphic resolution is not detailed more basinward sites experienced up to four times larger subsidence rates in the late neogene than in the oligocene miocene with a peak in the pliocene wells at the basin edge experienced much less subsidence or showed uplift the observations are consistent with a rapid change of intraplate stress at the cause for this observed transition in neogene subsidence major reorganizations of spreading direction and rate occurred during the pliocene along the entire atlantic spreading system possibly in conjunction with more global changes in plate motions we propose that the associated changes in intraplate stress caused the excess margin subsidence relative uplift along basin edges is consistent with this mechanism of relative movement and may explain apparent eustatic changes in sea level

cenozoic uplift and subsidence in the north atlantic region geological evidence revisited abstract the topographic evolution of the passive margins of the north atlantic during the last 65 myr is the subject of extensive debate due to inherent limitations of the geological geomorphological and geophysical methods used for studies of uplift and subsidence we have compiled a database of sign time and amplitude where possible of topographic changes in the north atlantic region during the cenozoic 65 0 ma our compilation is based on published results from reflection seismic studies aft apatite fission track studies vr vitrinite reflectance trends maximum burial sediment supply studies mass balance calculations and extrapolation of seismic profiles to onshore geomorphological features the integration of about 200 published results reveal a clear pattern of topographic changes in the north atlantic region during the cenozoic 1 the first major phase of cenozoic regional uplift occurred in the late palaeocene early eocene ca 60 50 ma probably related to the break up of the north atlantic between europe and greenland as indicated by the northward propagation of uplift it was preceded by middle palaeocene uplift and over deepening of some basins of the north sea and the surrounding areas 2 a regional increase in subsidence in the offshore marginal areas of norway the northern north sea the northern british isles and west greenland took place in the eocene ca 57 35 ma 3 the oligocene and miocene 35 5 ma were characterized by regional tectonic quiescence with only localised uplift probably related to changes in plate dynamics 4 the second major phase of regional uplift that affected all marginal areas of the north atlantic occurred in the plio pleistocene 5 0 ma its amplitude was enhanced by erosion driven glacio isostatic compensation despite inconclusive evidence this phase is likely to be ongoing at present

prefrontal bore mixing rainbow ridge a 1 950 m deep upthrusted ultramafic block along the axis of the mid atlantic ridge has an active hydrothermal vent system at 2 400 m on its western slope however within one kilometer from the vent excessive temperatures are barely measurable probably due to strong turbulent mixing this mixing is studied here using a 400 m long high resolution temperature sensor array moored with a 600 m ranging 75 khz acoustic doppler current profiler rich internal wave turbulence was recorded characterized by 100 200 m upshoots and 200 m large overturning in particular near the end of the warming phase of the up and down moving tide these highly nonlinear internal waves of tides interacting with buoyancy frequency waves extend up to 400 m above the sloping bottom of the ridge whilst a turbulent bottom boundary layer could barely be defined the more intense turbulence higher up in the water column is suggested to lead to the strong dispersion of the hydrothermal plume

sedimentological evolution of mississippian kekiktuk formation sagavanirktok delta area north slope alaska abstract the reservoir interval in the endicott field located under the delta of the sagavanirktok river east of prudhoe bay is the mississippian kekiktuk formation the rocks are quartzose and lithofacies and sequence analysis of core material shows that the kekiktuk in that area can be subdivided into three sedimentologically distinct intervals each of which reflects a different fluviatile depositional environment the lowermost interval zone 1 rests directly on metamorphic basement and comprises interbedded coal mudstones siltstones and fine grained sandstones these rocks were deposited in a very low lying swamp plain containing local lakes and sluggish highly sinuous streams zone 1 is overlain sharply by zone 2 which comprises medium to coarse grained multistory andstone that was deposited within an unconstrained braided river system the braid plain contained both ephemeral and permanent lakes and periodic gravity flows deposited coarser sediment into the latter that sequence passes gradationally upward into zone 3 which is composed of coarse medium and fine grained sandstones as well as siltstones mudstones and coals the lower part of zone 3 is dominated by upward fining sandstone sequences interpreted as channel bars deposited within a moderately sinuous fluvial system they pass gradationally upward into other distinct upward fining sequences which differ in having higher proportions of siltstone mudstone and coal those rocks were deposited in a more highly sinuous meandering fluvial environment the rocks grade upward int shallow marine sediments of the kayak itkilyariak formations the vertical sequence within the kekiktuk in this area permits an interpretation of the structural history of the basin during kekiktuk time end of article last page 669

a deep ocean kelvin helmholtz billow train 1 detailed overturning is observed between 0 5 and 50 m above the sloping side of great meteor seamount canary basin using 100 moored temperature sensors 1 mk accurate sampling at 1 hz while previously reported frontal bores of 40 m amplitude can form with vigorous near bottom motions and sediment resuspension at the beginning of the upslope phase of large e g tidal carrier waves the downslope phase presented here is more permanently turbulent away from the bottom this turbulence is inferred from high resolution temperature space time series which reveal ubiquitous finger like structures it occurs during the clear water tidal phase with low amounts of acoustic scatterers the high frequency finger like motions n n the buoyancy frequency are observed simultaneously with local mode 2 near n inertio gravity waves and overall shear s n they show large temperature variations 5 10 m vertical amplitudes and occasionally develop kelvin helmholtz billows the typical eulerian period of these firstly observed deep ocean billows amounts 50 10 s

comparison of ellison and thorpe scales from eulerian ocean temperature observations ocean turbulence dissipation rate is estimated either by means of microstructure shear measurements or by adiabatically reordering vertical profiles of density the latter technique leads to the estimate of the thorpe scale which in turn can be used to obtain average turbulence dissipation rate by comparing the thorpe scale to the ozmidov scale in both cases the turbulence dissipation rate can be estimated using single vertical profiles from shipborne instrumentation we present here an alternative method to estimate the length scale of overturns by using the ellison length scale the ellison scale is estimated from temperature variance just beyond the internal wave band measured by moored instruments we apply the method to high resolution temperature data from two moorings deployed at different locations around the josephine seamount north eastern atlantic ocean in a region of bottom intensified turbulence the variance of the temperature time series just above the internal wave frequency band is well correlated with the thorpe scale the method is based on the time frequency decomposition of variance called maximum overlap discrete wavelet transform the results show that the ellison length scale can be a viable alternative to the thorpe scale for indirectly estimating turbulence dissipation rate from moored instruments in the ocean if time resolution is sufficiently high we suggest that fine structure contaminated temperature measurements can provide reliable information on turbulence intensity

two oil types on north slope of alaska implications for exploration forty oil samples from across the north slope of alaska have been analyzed by the u s bureau of mines and the u s geological survey results of these analyses suggest two separate genetic oil types the first the simpson umiat oil type occurs in reservoir rocks of cretaceous and quaternary age and includes oil from seeps in the skull cliff cape simpson manning point and ungoon point areas and oils from wolf creek test 3 and the cape simpson and umiat oil fields these are higher gravity low sulfur oils with no or slight odd numbered n alkane predominance and pristane to phytane ratios greater than 1 5 also these oils have dgr13c values ranging from 29 1 to 27 8 parts per thousand ppt and dgr34s values from 10 3 to 4 9 ppt the s cond type the barrow prudhoe oil type occurs in reservoir rocks of carboniferous to cretaceous age and includes oils from south barrow gas field prudhoe bay oil field and the fish creek test well 1 physical properties of barrow prudhoe oils are variable but in general the oils are medium gravity high sulfur oils with slight even numbered n alkane predominance and pristane to phytane ratios less than 1 5 also these oils have dgr13c values of 30 3 to 29 8 ppt and dgr34s values from 30 0 to 2 1 ppt the two types are believed to originate from different source rocks the barrow prudhoe type may have originated from a carbonate or other iron deficient source rock and the simpson umiat type from a siliciclastic source rock occurrences of the two oil types when outlined on a map indicate at least two areas for additional exploration for the barrow prudhoe type in stratigraphic traps along and adjacent to the barrow arch and for the simpson umiat type in cretaceous rocks along the trend between the simpson and umiat oil fields and in cretaceous and tertiary rocks from prudhoe bay field to the william o douglas arctic wildlife range

sedimentary basins formed and carried piggyback on active thrust sheets small sedimentary basins that formed on the apennine southern margin of the po basin complex northern italy have been studied using borehole and seismic reflection information and their evolution can be dated using the largely marine biostratigraphy of the miocene to quaternary sediments these studies show that the basins formed and were filled while being carried on moving thrust sheets and they are therefore named piggyback basins each of these basins corresponds to the active phase of a different thrust front ramp on the pyrenean northern margin of the ebro basin complex northern spain similar piggyback basins formed between eocene and mid miocene time they have since been uplifted and eroded and may therefore be studied in outcrop in northern spain much of the basin fill sediment was deposited in nonmarine environments

the skewness of temperature derivatives in oceanic boundary layers abstract the skewness of the derivative of temperature measured by sensors in the upper ocean boundary layer in convective conditions has been measured and is observed to have a sign opposite to that found in conditions of stable heating this is consistent with observations in the atmospheric boundary layer high resolution measurements in the benthic boundary layer on a continental rise show a variation of skewness during the m2 tidal cycle which dominates the motion with negative skewness consistent with conditions favoring convection occurring during the upslope phase of the motion the observations are compared with laboratory studies of the reflection of internal waves from a slope we suggest that information about the gross features of a turbulent oceanic boundary layer flow may be derived from relatively simple measurements

evolution of sedimentary basins in the canadian arctic since middle proterozoic time two long lasting phases affected the canadian arctic archipelago each forming a different sedimentary basin the franklinian basin which was floored by continental or quasi continental crust received 10 km or more of clastic carbonate and volcanic rocks from the mid proterozoic to devonian internal parts of the basin were deformed intruded and metamorphosed locally and external parts were folded and thrust cratonward by compressional episodes of the ellesmerian orogeny which culminated in the late devonian this marked the end of a phase at which time the entire region may have been emergent the nature of plate interactions that produced ellesmerian deformation are unknown the second phase began in the early carboniferous when plate movements of the boreal rifting episode created the proto canada basin by left hand transform motion of a plate along the modern continental margin and the location of the kaltag fault of northern alaska as a marginal side effect of that motion the sverdrup basin developed as a peri cratonic incipient rift from the carboniferous to late cretaceous the basin received about 13 km of cratonic derived clastic detritus from late cretaceous to early tertiary time the arctic archipelago was disrupted by the interference of two plate movements originating in the arctic and north atlantic regions those events had three main effects the craton was extended and a graben filled depression formed in the southeastern part of the archipelago the eastern and central parts of the sverdrup basin were compressed and uplifted eurekan orogeny and resultant elastics prograded northwestward toward the canada basin to form the arctic continental terrace wedge

tectonostratigraphic modelling of cenozoic uplift and erosion in the south western barents sea abstract cenozoic subsidence patterns in the south western barents sea punctuated by periods of uplift and erosion deviate from thermal subsidence patterns predicted by stretching models of basin formation three regional seismic lines crossing the south western barents sea show that a substantial amount of erosion occurred at the shelf whereas at the margin a thick wedge of cenozoic sediments has been observed quantitative basin modelling of the profiles allows different mechanisms for erosion and uplift to be tested the modelling shows that the palaeocene early eocene flank uplift during rifting and late neogene intraplate stresses superimposed on a middle miocene sea level change and pliocene quaternary de glaciation play a major role in the development of the late cenozoic stratigraphy stress induced uplift of flank areas could augment the regional uplift of scandinavia possibly leading to climatic changes such as the onset of cooling and glaciation intraplate stresses related to plate boundary processes in the north atlantic realm also have important implications for the depth of the hydrocarbon window in the south western barents sea

a three dimensional simulation of the hudson raritan estuary part ii comparison with observation abstract results from a time dependent three dimensional numerical simulation of the hudson raritan estuary are compared with observations the comparison includes 1 instantaneous salinity contours across a transect in the estuary 2 amplitudes and phase of tidal constituents at four tide gauge and five current meter stations 3 mean currents at nine meter locations and mean salinity in the hudson river 4 kinetic energy spectra and 5 response to wind forcing of subtidal current at an observational station near the mouth of the estuary observations confirm the model s prediction of existence of density advection instabilities induced by differential advection of the three dimensional density field these instabilities produce intense vertical mixing and should significantly modify dispersion processes in the estuary effects of neap spring tides on vertical stratifications are also simulated by the model simulated m2 phase at three tide gauge stations show improvement over the m2 phases obtaine

the late mesozoic and cenozoic evolution of the sorvestsnaget basin a tectonostratigraphic mirror for regional events along the southwestern barents sea margin abstract seismic interpretation and mapping of the sorvestsnaget basin at the southwestern barents sea margin has revealed a complex basin history related to large scale plate tectonic movements in the norwegian greenland sea area the pre cenozoic evolution of the sorvestsnaget basin is poorly understood due to lack of well data and poor seismic data quality regional pre cenozoic geologic models that includes the sorvestsnaget basin should await more and better data prior to break up and sea floor spreading in the norwegian greenland sea late cretaceous and palaeocene shear movements along the senja fracture zone led to structuring and possibly elevation of the southern part of the basin as sea floor spreading took place and propagated northwards along the senja fracture zone the western areas of the basin were uplifted and eroded two large and two smaller intrabasinal features in the southern sorvestsnaget basin are characterised by a low values on the gravimetric anomaly maps b surrounding synforms and c little response on magnetic anomaly maps the features have been interpreted as salt structures the tertiary evolution of intrabasinal salt structures seems to have been governed by extensional faulting and subsidence of the margin during the late palaeocene and eocene periods the oligocene and miocene periods were characterised by local and regional uplift of the sorvestsnaget basin respectively during these periods the area in particular the western part of the basin was subjected to transpressional compressional forces which can be tentatively correlated to contemporaneous large scale plate reorganisations and variations of sea floor spreading rates in the norwegian greenland sea the oligocene and miocene transpressional compressional events influenced the salt structures and is here suggested to be partially responsible for the complex expression of the largest salt structures the late neogene and pleistocene periods are represented by a thick westward prograding wedge indicating subsiden3e with coinciding high sediment input to and minor adjustment of the salt structures in the sorvestsnaget basin

new upper paleozoic and lower mesozoic stratigraphic units central and western brooks range alaska the sequence of rocks described lies primarily in the delong and endicott mountains in the western and central parts of the brooks range northern alaska new names are given to dominantly siliceous and shaly sedimentary rocks of mississippian through early middle jurassic age the kuna formation new name consists dominantly of black bedded chert shale limestone and dolomite within the lisburne group some beds are phosphatic and mafic extrusive igneous rocks occur in a few areas paleontologic data suggest an early mississippian to early or middle pennsylvanian age for the kuna formation because the formation intertongues eastward with light colored shallow water carbonate rocks of the wachsmuth and alapah limestones of the lisburne group it is also assigned to t e lisburne group light colored shallow water carbonate rocks of other formations of the lisburne group were apparently also deposited on the south but have been telescoped northward by thrust faulting over the darker kuna formation the formation ranges up to 100 m in thickness the etivluk group new name is composed of dominantly siliceous beds of the previously named siksikpuk formation and overlying otuk formation new name new paleontologic data suggest that the siksikpuk is of pennsylvanian permian and early triassic age the otuk formation consists of up to 100 m rhythmically interbedded chert silicified limestone and shale previously assigned in this area to the shublik formation a thin but distinctive zone of early middle jurassic organic shale and dolomitic limestone ocally present within the top of the otuk constitutes the blankenship member new name which is up to 7 m thick paleontologic data indicate that the otuk formation ranges in age from late early triassic to early middle jurassic these dominantly siliceous stratigraphic units appear to be limited to the allochthons of the western and central brooks range they are not known to be present on the autochthonous complex of the northeastern brooks range and subsurface arctic slope

a three dimensional simulation of the hudson raritan estuary part i description of the model and model simulations abstract a time dependent three dimensional finite difference simulation of the hudson raritan estuary is presented the calculation covers july september 1980 the model estuary is forced by time dependent observed winds tidal elevation at open boundaries and river and sewage discharges turbulence mixing coefficients in the estuary are calculated according to a second moment turbulence closure submodel horizontal diffusivities are zero in the simulation and small scale eddies produced by the interaction of unsteady three dimensional velocity and salinity fields with coastline and bottom bathymetry were resolved by the model these eddies are important physical elements in shear dispersion processes in an estuary model results show unstably stratified water columns produced by advection of waters of different densities these instabilities produce intense mixing with vertical eddy diffusivities reaching 2 3 times their neutral values they occur most frequently at slack currents during initial s

temperature statistics above a deep ocean sloping boundary we present a detailed analysis of temperature statistics in an oceanographic observational dataset the data are collected using a moored array of thermistors 100 text m 100 m tall and starting 5 text m 5 m above the bottom deployed during four months above the slopes of a seamount in the north eastern atlantic ocean turbulence at this location is strongly affected by the semidiurnal tidal wave mean stratification is stable in the entire dataset we compute structure functions of order up to 10 of the distributions of temperature increments strong intermittency is observed in particular during the downslope phase of the tide and farther from the solid bottom in the lower half of the mooring during the upslope phase the temperature statistics are consistent with those of a passive scalar in the upper half of the mooring the temperature statistics deviate from those of a passive scalar and evidence of turbulent convective activity is found the downslope phase is generally thought to be more shear dominated but our results suggest on the other hand that convective activity is present high order moments also show that the turbulence scaling behaviour breaks at a well defined scale of the order of the buoyancy length scale which is however dependent on the flow state tidal phase height above the bottom at larger scales wave motions are dominant we suggest that our results could provide an important reference for laboratory and numerical studies of mixing in geophysical flows