age of the brookville gneiss and associated rocks southeastern new brunswick the brookville gneiss is a medium to high grade quartz feldspar biotite and hornblende quartz feldspar biotite gneiss found north and northeast of saint john new brunswick the green head group

an introduction to wavelet transform tidal analysis methods continuous wavelet transforms cwts provide an approach to understanding the numerous tidal phenomena that deviate markedly from an assumed statistical stationarity or exact periodicity inherent in traditional tidal methods use of wavelets allows determination of the degree of non stationarity present in time series such as estuarine and shelf currents usually treated as stationary wavelets also provide a consistent analysis of tidal and non tidal variance a feature often essential for dynamical analyses of non stationary tides we summarize basic notions of the wavelet transform also known as a perfect reconstruction filter bank or a multire solution analysis contrast them with those of harmonic analysis and fourier transforms construct a continuous wavelet transform basis with a scale selection especially adapted to tidal problems describe possibilities for analysis of scalar and vector quantities define a criterion for knowledge of independence of process between adjoining scales and illustrate use of wavelet tools with several examples in contrast to the nearly periodic barotropic tide typical of coastal stations this paper analyses processes that are in part tidally driven but non stationary e g baroclinic tidal currents river tides continental shelf internal tides and some kinds of biological activity in the coastal ocean in all cases wavelet analysis provides a consistent linear analysis of tidal and non tidal variance and reveals features that harmonic analysis on a fourier transform approach could not elucidate

temporal and spatial variability of tidal fluvial dynamics in the st lawrence fluvial estuary an application of nonstationary tidal harmonic analysis predicting tides in upstream reaches of rivers is a challenge because tides are highly nonlinear and nonstationary and accurate short time predictions of river flow are hard to obtain in the st lawrence fluvial estuary tide forecasts are produced using a one dimensional model one d forced downstream with harmonic constituents and upstream with daily discharges using 30 day flow forecasts from lake ontario and the ottawa river although this operational forecast system serves its purpose of predicting water levels information about nonstationary tidal fluvial processes that can be gained from it is limited particularly the temporal changes in mean water level and tidal properties i e constituent amplitudes and phases which are function of river flow and ocean tidal range in this paper a harmonic model adapted to nonstationary tides ns tide was applied to the st lawrence fluvial estuary where the time varying external forcing is directly built into the tidal basis functions model coefficients from 13 analysis stations were spatially interpolated to allow tide predictions at arbitrary locations as well as to provide insights into the spatiotemporal evolution of tides model hindcasts showed substantial improvements compared to classical harmonic analyses at upstream stations the model was further validated by comparison with one d predictions at a total of 32 stations the slightly lower accuracy obtained with ns tide is compensated by model simplicity efficiency and capacity to represent stage and tidal variations in a very compact way and thus represents a new means for understanding tidal rivers

estuary shelf interactions off the changjiang delta during a dry wet seasonal transition abstract estuary shelf interaction is very complex and vital for maintaining healthy ecosystem in the estuaries and adjacent seas the topic has been intensively studied through cruise observations and numerical models but less by long term observations at a fixed station we present here for the first time roughly 2 months adcp and ctd continuous data from the xiaoqushan pilot station of seafloor observatory aiming to deliberate river plume frontal processes off the changjiang estuary in response to river discharge transition from the dry to wet season in 2009 multiple lines of evidence attest that inner river plume is always in a bottom trapped form but isohalines and isothermals are very sensitive to seasonal variations in freshwater input wind climate and surface heating semidiurnal oscillations of salinity and temperature are good tracers for seasonal variations in plume frontal processes in the dry season both salinity and temperature have weak semidiurnal oscillations due to minimal cross shore straining under strong mixing conditions near the inner plume front where isohaline and isothermal are nearly vertical with small horizontal salinity and temperature gradient they are suddenly interrupted by a sharp increase of semidiurnal salinity oscillations owing to the arrival of newly established plume front with a less steep isocline slope but a maximum horizontal salinity gradient of 0 8 psu km the response time of inner plume front to the first discharge increasing pulse is roughly two weeks but should change a lot when examined at different plume locations and under varied river discharge increasing magnitudes and rates the frontal processes mirror well the river discharge fluctuations in the transitional period which lasts for a few weeks before entering a typical wet season the latter features strongest semidiurnal temperature oscillations linked with summer surface heating and highly depressed semidiurnal salinity oscillations because the main plume path shifts from southward to northeastward due to alternating southerly to northerly prevailing winds the three stages of inner plume frontal processes can be more clearly demarcated by the wavelet power spectral and the amplitudes of semidiurnal diurnal oscillations of salinity and temperature through wavelet transform and the associated band pass filtering methods the seasonal plume frontal transition has been vividly portrayed for the first time through secular observation at the fixed station in the river plume region significantly improving our understanding their controlling factors and mechanisms

particle trapping in estuarine tidal flows particle trapping in estuarine turbidity maxima etm is caused primarily by convergent mean and or tidal fluxes of sediment the result is an approximately bell shaped along channel distribution of vertically integrated tidal cycle mean suspended sediment concentration observations from the columbia river estuary suggest that 1 strong two layer or internal along channel residual and overtide flows are generated by time varying stratification and 2 correlations between the near bed velocity and the suspended sediment fields at these frequencies are important in landward transport of sediment a new spatially and temporally integrated form of the sediment conservation equation has been derived to analyze this trapping process time changes in tidally averaged sediment concentration between two estuarine cross sections can be shown to be related to the divergence of the seaward river flow transport the divergence of velocity shear sediment stratification correlations for the mean flow and each tidal constituent and net erosion or deposition at the bed vertically integrated variables other than seaward river transport are absent from this integrated balance analysis of sediment fluxes using this balance supports the idea that internal residual and overtide circulations are primarily responsible for the landward sediment transport on the seaward side of etm found near the upstream limits of salinity intrusion the balance also shows that attempts to represent fluxes causing trapping of sediment in an etm as a product of a time mean vertically integrated along channel gradient and a diffusivity inevitably lead to the appearance of countergradient transport and thus a negative diffusivity on the seaward side of the etm this result occurs because the trapping process is inherently nonlinear and at least two dimensional and because a one dimensional representation is physically unrealistic

petrology and geochemistry of cambrian volcanic rocks from the avalon peninsula newfoundland middle cambrian basaltic flows lapilli tuffs and their feeder pipes on the avalon peninsula newfoundland show high nb y and low zr nb ratios and high concentrations of incompatible elements such as nb and zr which are typical of alkaline rocks the compositions of relict clinopyroxenes are consistent with these conclusions relatively low mg values and low cao and high tio2 concentrations show that the flows represent evolved compositions petrographic evidence and trends in trace element data indicate that the range of bulk rock compositions in the feeder pipes can be related to precipitation of augite plagioclase and olivine as well as late removal of fe ti oxides and apatite the negative correlation shown by noncumulus rocks between mg and al2o3 the relatively high mg values of the flows and the alkaline nature of the rocks distinguish them from most flood basalts and relate them to rift basalts low al2o3 concentrations at the highest mg values may be related to genesis in a garnet r

modelling salinity and circulation for the columbia river estuary abstract simulations of the time and depth dependent salinity and current fields of the columbia river estuary have been performed using a multi channel laterally averaged estuary model the study simulated two periods the first in october 1980 with low riverflow of about 4 000m 3 s 1 which showed marked changes in the salinity intrusion processes between neap and spring tides and second in spring 1981 with high riverflow varying between 7 000 and 15 000m 3 s 1 which showed the rapid response of the salinity intrusion to changes in riverflow and that vertical mixing did not change character with increasing tidal energy because of the maintenance of stratification by freshwater flow an extreme low flow simulation riverflow of 2 000m 3 s 1 showed a more partially mixed character of the estuary channels with tidal dispersion of salt across the taylor sands from the north channel to the upper reaches of the navigation channel asymmetries in the non linear tidal mean flows in the flood and ebb circulations and salinity intrusion characteristics between the two major channels were observed at all riverflows the model confirms jay and smith s 1990 analysis of the circulation processes in that tidal advection of salt by the vertically sheared tidal currents is the dominant mechanism by which the salinity intrusion is maintained against large freshwater flows an accurate finite difference method which minimized numerical dispersion was used for the advection terms and was an important component in reasonably simulating the october neap spring differences in the salinity intrusion the simulations compare favorably with elevation current and salinity time series observations taken during october 1980 and spring 1981

non recognition of continental tholeiites using the ti y zr diagram continental tholeiites cannot be identified using the ti y zr diagram two hundred and thirteen analyses from 16 localities representing 7 continental tholeiitic provinces all plot outside the within plate basalt field of this diagram

large seasonal modulation of tides due to ice cover friction in a midlatitude estuary abstractseasonal episodes of significant tidal damping reductions of tidal amplitudes as much as 50 and tidal modulation were observed in the hudson river estuary in the course of three consecutive winters from multiple tide gages through comparisons with united states coast guard ice reports it was hypothesized that these events correspond with an increase in ice concentration and the development of a seasonal ice field within the upper 170 km of the tidal hudson north of peekskill new york using stationary tidal harmonic and nonstationary wavelet analyses as well as numerical modeling it is shown that under ice friction is the primary cause of the observed modulations in tidal circulation water levels and currents throughout the 240 km long estuary upstream of the ice field edge at peekskill depth averaged tidal currents are greatly reduced under the ice cover through first order damping and vertical current profiles under the ice become parabolic tidal ranges increase near the edge of

modelling tidal energetics of the columbia river estuary abstract the columbia river estuary is shallow and has a mixed diurnal and semidiurnal tide strong riverflow broad tidal flats and variable channel cross section it is weakly non linear with respect to tidal forcing as measured by a ratio of tidal amplitude to depth these features common to many shallow estuaries were incorporated into a one dimensional harmonic transport model the harmonic method utilizes the fact that nearly all of the energy in the system is in a few fundamental tidal frequencies the first overtides thereof and the mean flow this allows the representation of the flow as a series of harmonic components whose spatial variability is determined by the model the model provides a qualitative explantation for and accurate quantitative predictions of along channel variations in tidal properties in terms of the momentum balance near the mouth of the estuary the boundary shear stress the pressure gradient and the acceleration terms are all important in the force balance and the tide behaves like a damped oscillator far upriver the pressure gradient is primarily balanced by friction at the bed and tidal wave propagation can be described as a diffusion process changes in the channel width in mid estuary cause partial reflection of the tidal wave and a maximum in tidal range this partial reflection decreases the tidal energy flux in the upstream direction the distribution of the time averaged energy fluxes was also determined from the model the analysis shows that there are two regions of high energy dissipation energy is supplied near the mouth of the estuary by the divergence of the landward flux of tidal potential energy and far upriver by the divergence of the seaward flux of fluvial potential energy these two regions of high dissipation are separated by a region of low dissipation the energy flux divergence minimum this spatial division of the estuary is mirrored in the system biology and geology it is likely that the energy flux divergence minimum is a common feature of shallow estuaries with strong riverflow

unravelling the causes of tidal asymmetry in deltas abstract tidal asymmetry in deltas is caused by both the intrinsic asymmetry resulting from the combination of astronomical tides and by nonlinear tidal interactions that occur in shallow water the relative importance of these sources of tidal asymmetry in delta channel networks have remained poorly studied partly due to the limitations of classical harmonic analysis ha in hindcasting nonstationary tides the pearl river delta prd is a multichannel system with rapidly changing bathymetry subject to severe human interventions this work applies a nonstationary harmonic model ns tide to hydrological data from 15 stations in the prd spanning the period 1961 2012 the spatiotemporal variation of multiple sources of tidal asymmetry is quantified by a skewness metric revealing how similar or dissimilar the development of alternative sources of tidal asymmetry develop in the delta subject to study a relative sensitivity coefficient rsc is introduced to decompose the contribution of tidal amplitude variations to multiple tidal asymmetries analytical results show the development of tides becoming gradually more asymmetric as they propagate into delta channel networks and how this depends on the river flow variation in the orientation of tidal asymmetries induced by different combinations of tidal constituents leads to a complex pattern of the overall tidal asymmetry in the prd our results show that tidal asymmetry in deltas can be significantly dependent on the river flow

seismic tomography from local crustal earthquakes beneath eastern rif mountains of morocco we applied a tomographic method to image an aseismic strike slip fault in north morocco and found that the occurrence of earthquakes is not only controlled by the state of tectonic stress but also by material heterogeneity in the crust we have constructed an integrated model of seismic electric magnetic and heat flow properties across northeastern morocco primarily based on a tomography inversion of local earthquake arrival times the seismic images obtained show a pronounced lowvelocity zone at 5 km depth parallels to the nekor fault coinciding with an anomalously high conductive and low gravity structure which is interpreted as a fault gouge zone and or a fluid filled subsurface rock matrix below 10 km depth a weak positive velocity zone indicates that the fault gouge is stable the seismicity and the seismic velocity results for the alhoceimas region show that the concentrations of earthquakes are confined in the high velocity area this anomaly is interpreted to be a brittle and competent layer of the upper crust that sustains seismogenic stress on the eastern coast line of morocco we infer that a high density high velocity body exists in the shallowest layers of the upper crust probably formed by miocene volcanic rocks d 2003 elsevier science b v all rights reserved

wavelet analysis for geophysical applications wavelet transforms originated in geophysics in the early 1980s for the analysis of seismic signals since then significant mathematical advances in wavelet theory have enabled a suite of applications in diverse fields in geophysics the power of wavelets for analysis of nonstationary processes that contain multiscale features detection of singularities analysis of transient phenom ena fractal and multifractal processes and signal com pression is now being exploited for the study of several processes including space time precipitation remotely sensed hydrologic fluxes atmospheric turbulence can opy cover land surface topography seafloor bathymetry and ocean wind waves it is anticipated that in the near future significant further advances in understanding and modeling geophysical processes will result from the use of wavelet analysis in this paper we review the basic properties of wavelets that make them such an attractive and powerful tool for geophysical applications we dis cuss continuous discrete orthogonal wavelets and wavelet packets and present applications to geophysical processes

river flow controls on tides and tide mean water level profiles in a tidal freshwater river 1 tidal rivers feature oscillatory and steady gradients in the water surface controlled by interactions between river flow and tides the river discharge attenuates the tidal motion and tidal motion increases tidal mean friction in the river which may act as a barrier to the river discharge time series of tidal water level amplitudes at five gauge stations along the river mahakam in indonesia and tidal flow velocity amplitudes at a discharge monitoring station were obtained applying wavelet analysis temporal variations in tidal damping coefficients for quaterdiurnal semidiurnal and diurnal tidal species were quantified from the observed amplitude profiles the analysis shows that tidal damping during the rising limb of a discharge wave differs from damping during the falling limb wavelet cross correlations between surface levels yielded empirical estimates of wave numbers an empirical relation between tidal damping and river flow is derived to describe subtidal bottom friction along an idealized tidal river resembling the mahakam the subtidal friction is decomposed into contributions from the river flow only from river tide interaction and from tidal asymmetry even for high river flow and low tidal velocity river flow enhances friction attributed to river tide interaction causing subtidal water level setup a simple multilinear regression model using subtidal bottom friction is employed to predict subtidal water levels at locations upstream with a relatively good agreement between predictions and observations the explicit expression shows the nonlinear dependence of subtidal friction on river flow velocity explaining the complex behavior of tidal mean surface level profiles

etude du champ magnetique anormal d origine intralithospherique the separation of the anomalous magnetic field with respect to the depth of lateral contrasts of conductivity is discussed in this paper it is shown that for most geophysical cases this separation is very simply performed for periods greater than 1800 s the anomalous field of an intralithospheric source is the difference between the observed anomalous field and the one related to the lateral contrasts of conductivity in the superficial part of the crust mostly the coast effect electromagnetic data observed in california are analysed using this method an anomalous field of intralithospheric source is shown to exist the study of this field provides us with indications about lateral variations of the physical and chemical conditions in the lithosphere the obtained results are in good agreement with data drawn from other earth sciences finally we show that such results can be obtained in other tectonically active areas japan and peruvian andes

river forced estuarine plumes abstract the development maintenance and dissipation of river forced estuarine plumes with and without seaward sloping bottom are studied by use of a three dimensional primitive equation model inside the estuary discussion is focused on how the coriolis force induces lateral asymmetries in the circulation four physical processes dictate the transient as well as the quasi steady circulation in moderately stratified estuaries 1 upper layer convergence during the transient spinup phase 2 upward entrainment leading to the two layer steady circulation pattern 3 upward stretching of the lower layer vortex during the spindown period and 4 in the presence of a seaward bottom slope the left bounded tendency of the landward undercurrent for all phases of development deviations from the laterally averaged circulation pattern caused by these processes are discussed over the shelf various types of plumes are defined according to the visual appearance of the surface salinity field the four types of p

chloritization and carbonatization of cambrian volcanic rocks in eastern newfoundland and southern new brunswick canada abstract cambrian basaltic flows and volcaniclastic rocks on the avalon peninsula of newfoundland and from the beaver harbour area of southern new brunswick show two phases of alteration which resulted in the formation of chlorite and carbonate in most of the rocks calculations which account for volume changes show that chlorite forming reactions resulted in the addition of mg sr p and mn and the removal of k rb ti zr v and fe from the beaver harbour rocks whereas ca sr ba rb and k were removed and ni cr ga v and mn added to avalon samples these results resemble those produced by basalt seawater interaction particularly in the beaver harbour case where mg increases in the beaver harbour rocks carbonate metasomatic reactions led to the addition of ca sr na mg p y and zn and removal of ba rb and k in proportion to the amount of carbonate added ca na sr and co 2 were added and mg removed in the avalon rocks with the exception of mg removal avalon the behaviour of most elements from both localities resembles that observed in systems with high co 2 activity the increase of p and y in the beaver harbour rocks indicates f may have also been an important constituent of metasomatic fluids

modulation of shallow water tides in an inlet basin system with a mixed tidal regime 1 during the autumn of 1999 a 56 day long observational study of sea surface elevation and currents was made in yavaros bay a shallow inlet basin system with a mixed tidal regime in the gulf of california during the late spring of 1998 a similar experiment was performed at the same coastal lagoon as well although it was shorter the measurements are used to investigate the modulation of the shallow water tides the complex demodulation approach revealed that not only the moon s path cycle modified the generation of shallow water tides but also the lunar declination and the solar declination the sixth diurnal tides showed a spring neap modulation the fifth diurnal tides were above the noise level only close to the summer solstice the fourth diurnal tides were modulated by the spring neap cycle at the basin but this modulation was changed by friction at the inlet at this site the fourth diurnal band of the tidal current had a maximum in amplitude during neap tides the third diurnal tides were irregularly modulated the advection and the nonlinear continuity terms were correlated with the third and fourth diurnal bands of the tidal current at the inlet the quadratic friction terms were correlated with the sixth fourth and third diurnal bands of the tidal current the semidiurnal tides mainly provided the energy of the tidal residual current during the autumnal equinox of 1999 near the summer solstice of 1998 the semidiurnal band induced a residual current seaward oriented while the diurnal band induced a residual current landward oriented

tidal fluvial interaction in the guadalquivir river estuary spatial and frequency dependent response of currents and water levels tidal fluvial interaction in the gre

the fluctuating longshore pressure gradient on the pacific northwest shelf a dynamical analysis abstract the majority of papers on pacific northwest shelf dynamics have emphasized the relationship between longshore wind stress 3 and longshore velocity v however attempts to illustrate a balance of momentum in the longshore direction have not been encouraging 3 sol h where h is water depth has insufficient magnitude to balance the vertically averaged longshore acceleration vt at least during summer in this paper it is demonstrated that the missing momentum is provided by the longshore pressure gradient force py the pressure gradient was estimated using tide gauge and atmospheric pressure data at stations separated by roughly 400 km seasonal and long term means from hickey and pola and in some cases nonseasonal monthly anomalies from enfield and allen were added to the sum of the tide gauge and atmospheric pressure data to form time series of total subsurface pressure the pressure data were multiplied by an offshore deny factor to simulate coastal trapping the analysis was performed

lithostratigraphy of the cambrian lower ordovician saint john group southern new brunswick the cambrian lower ordovician saint john group of the saint john area southern new brunswick has historically been subdivided into 11 formations the existing scheme is inappropriate however as many of the supposed formations particularly those of middle cambrian early ordovician age were distinguished on a biostratigraphic rather than lithostratigraphic basis we suggest the sequence can be more appropriately subdivided into seven formations each of which can be clearly and easily identified by the field geologist lower cambrian formations comprise from base to top the ratcliffe brook glen falls and hanford brook formations all of which are retained from the previous nomenclature middle cambrian strata comprise the forest hills formation to replace the fossil brook and porter road formations and upper cambrian strata the king square formation to replace the hastings cove and agnostus cove formations and silver falls formation to replace the black shale brook and narrows formations

the columbia river plume study subtidal variability in the velocity and salinity fields a comprehensive study of the strongly wind driven midlatitude buoyant plume from the columbia river located on the u s west coast demonstrates that the plume has two basic structures during the fall winter season namely a thin 5 15 m strongly stratified plume tending west to northwestward during periods of southward or light northward wind stress and a thicker 10 40 m weakly stratified plume tending northward and hugging the coast during periods of stronger northward stress the plume and its velocity field respond nearly instantaneously to changes in wind speed or direction and the wind fluctuations have timescales of 2 10 days frictional wind driven currents cause the primarily unidirectional flow down the plume axis to veer to the right or left of the axis for northward or southward winds respectively farther downstream currents turn to parallel rather than cross salinity contours consistent with a geostrophic balance in particular during periods when the plume is separated from the coast currents tend to flow around the mound of fresher water at distances exceeding about 20 km from the river mouth the along shelf depth averaged flow over the inner to midshelf is linear and depth averaged acceleration is governed to lowest order by the difference between surface and bottom stress alone in this region along shelf geostrophic buoyancy driven currents at 5 m calculated from surface density and along shelf geostrophic wind driven currents computed from a depth averaged linear model are comparable in magnitude 10 25 cm s 1

jurassic volcanic rocks of the northern north sea the lavas and minor intrusive rocks from the jurassic volcanic province of the forties piper area of the north sea can be subdivided into three distinct series on the basis of petrography whole rock chemistry and mineral chemistry these series which probably evolved from one or more alkali olivine basalt parent magmas are i an ankaramite basaltic hawaiite hawaiite series ii an alkali olivine basalt hawaiite series and iii an intrusive hawaiite intrusive mugearite series variations within series are due mainly to differential distribution of mafic phenocryst phases but liquid immiscibility and magmatic fractionation are also believed to have contributed the middle jurassic volcanism in the north sea area is thought to be related to the tensional tectonic regime which existed in nw europe during the jurassic or to be due to a region of high heat flow extending northeastwards from the contemporary spreading axis between iberia and newfoundland and possibly to a combination of the two

2 d or 3 d interpretation of conductivity anomalies example of the rhine graben conductivity anomaly summary evidence of a conductivity anomaly in the rhine graben was first given about 15 years ago and consequently led to the definition of various models of induction in the region for periods ranging from a few minutes to a few hours these models reflect two antagonistic ways of explaining the observed anomalous variations of the magnetic field direct induction in a two dimensional 2 d structure or static distortion of telluric currents by the resistive crystalline vosges france and schwarzwalde germany massifs we discuss the two approaches using a simple formalism in particular we show that the self induction related to the anomalous currents flowing in the rhine graben is negligible for periods larger than 1000 s and that even though the static distortion of telluric currents does account for the observed anomaly 2 d models can explain some of its features we also show how the channelled currents are induced in the large sedimentary basins surrounding the area under study an experimental verification of this result is given

the shelburne dike an early mesozoic diabase dike in nova scotia mineralogy chemistry and regional significance a diabase dike about 140 km long the shelburne dike cuts in a northeasterly direction across the southwestern part of nova scotia the dike recently dated at 201 ma forms part of a major appala

modeling the residual circulation of a coastal embayment affected by wind driven upwelling circulation of the ria de vigo nw spain 1 the barotropic and baroclinic nontidal circulations of the ria de vigo nw spain are studied using the three dimensional finite difference model hamsom hamburg shelf ocean model the external forcing acting on the system includes winds freshwater inflow in the inner part of the ria and all over its surface and heat exchange with the atmosphere modeled velocity is compared with data from an aanderaa dcm12 acoustic doppler current meter at one site of the ria and predicted salinity and temperature fields contrasted with seabird conductivity temperature depth data along the main channel of the ria all predicted current salinity and temperature fields are in good agreement with experimental data a new residual circulation pattern of the ria de vigo and its dependence on coastal winds is described according to this pattern the typical estuarine two layer circulation overlays in the outer part of the ria with a lateral circulation resulting in a three dimensional dynamics the lateral circulation is induced by interaction between the southward northward alongshore coastal jet associated with upwelling downwelling winds and the topographic configuration of the ria

heat flow in the westernmost part of the alpine mediterranean system the rif morocco abstract heat flow density hfd and thermal gradient calculated on the basis of oil well data in the rif vary from 50 to 90 mw m 2 and from 20 to 50 c km respectively short term variations in the west can be attributed to water circulation and lateral heat conductivities contrast along the pre rif thrusting front and at the limits between the main structural units the gharb basin the south rifian ridges and the pre rif nappe high hfd and thermal gradient values are determined in the southwest of the study area this zone extends the central moroccan massif which is well known by its high thermal manifestations the external rif shows a tendency of increasing hfd toward northeastern morocco and the alboran sea in agreement with the geophysical observations electrical conductive structures great negative bouguer anomaly shear velocity attenuation high upper mantle p velocity the thermal structure of the external rif would be a consequence of the presence at subcrustal depths of hot and low density asthenospheric material overlying a high velocity lithospheric body beneath the rif betic belt

electrical resistivity structure of the eastern moroccan atlas system and its tectonic implications the electrical resistivity structure of the crust and upper mantle of the atlas mountain system was studied using magnetotelluric and geomagnetic deep soundings field experiments were done in eastern morocco along a traverse from the anti atlas to the rides rifaines in two campaigns in 1983 and 1988

palaeozoic within plate volcanic rocks in nova scotia canada reinterpreted isotopic constraints on magmatic source and palaeocontinental reconstructions palaeozoic volcanism in the avalon terrane of northern nova scotia occurred during three time intervals cambrian early ordovician late ordovician early silurian and middle late devonian in the meguma terrane of southern nova scotia palaeozoic volcanism is limited to the middle ordovician geochemical data show that most of these volcanic rocks are bimodal within plate suites initial e nd signa tures range from 5 4 to 1 9 in the rhyolites and 6 8 to 2 7 in the basalts a difference attributable to the absence or presence respectively of a significant crustal component the data and regional tectonic settings of the avalon and meguma terranes suggest that the volcanism was generated in three different within plate settings 1 cambrian early ordovician volcanism related to thermal decay of late proterozoic arc magma tism during transtensional deformation 2 middle ordovician early silurian volcanism during sinistral tele scoping between laurentia and gondwana where extensional bends in the appalachians produced rifting and 3 devonian volcanism resulting from lithospheric delamination during dextral transpression and tele scoping in each setting active faults served as conduits for the magmas nd isotopic data indicate that the source of the palaeozoic felsic volcanic rocks is isotopically indistinguishable beneath southern and northern nova scotia and did not substantially change with time this crustal source appears to have separated from the mantle during the proterozoic a conclusion consistent with the hypothesis that the palaeozoic rocks in nova scotia were deposited upon a late proterozoic oceanic cratonic volcanic arc terrane the nd data when combined with published faunal palaeomagnetic and u pb isotopic data suggest that the avalon terrane was peripheral to gondwana off northwestern south america during neoproterozoic and early palaeozoic times

late precambrian to late devonian mafic magmatism in the antigonish highlands of nova scotia multistage melting of a hydrated mantle five suites of alkalic basalt ranging in age from late precambrian to late devonian are found in the antigonish highlands of nova scotia in contrast on neighbouring cape breton island alkalic basalts are rare even in suites that are contemporaneous with those in the antigonish highlands late precambrian alkalic basalts in the antigonish highlands are genetically associated with calc alkalic rocks and are probably subduction related whereas the younger suites are continental rift related and within plate major and compatible trace element abundances can be explained by crystal fractionation of olivine clinopyroxene orthopyroxene spinel garnet however incompatible trace element concentrations are strongly influenced by mantle metasomatism that occurred prior to or synchronously with the oldest alkalic rocks the metasomatic event enriched the mantle in fe ti p zr and light rare earth elements the trace element composition of the younger suites is similar to that of the oldest alkali

interaction of fluctuating river flow with a barotropic tide a demonstration of wavelet tidal analysis methods wavelet transforms provide a valuable new tool for analysis of tidal processes that deviate markedly from an assumption of exact periodicity inherent in traditional harmonic analysis a wavelet basis adapted to nonstationary tidal problems is constructed and employed to analyze the modulation of the external tide in a river by variations in streamflow interaction of a surface tide with river flow is the best available demonstration of the continuous wavelet transform cwt methods developed it is the simplest and perhaps the only nonstationary tidal process for which both sufficient data and dynamical understanding exist to allow detailed comparisons between cwt analyses and analytical predictions of the response of tides to nontidal forcing variations at upriver locations of low frequency elevation river stage zr and three tidal species are deduced from cross sectionally integrated equations for landward propagation in a channel of constant cross section with quadratic friction the log of the amplitude of the diurnal d1 semidiurnal d2 and quarterdiurnal d4 elevations should vary at far upriver locations with the square root of the river flow qr and river stage zr should depend on the square of river flow convergent geometry and species species frictional interactions modify these predictions somewhat cwt analyses show that the predicted amplitude behavior for the tidal species is approximately correct best results are obtained for the dominant dynamically simplest processes zr and d2 in the past further progress in understanding river tides has been limited by a lack of data analysis tools data analysis tools are now clearly better than the available analytical solutions

consequences tectoniques de l existence d une anomalie de conductivite electrique au nord du maroc anomalous transient variations of the geomagnetic field in northern morocco and southern spain have been described previously for periods ranging from 10 min to 2 h these results have been reinves

revised stratigraphy of the long reach area southern new brunswick evidence for major northwestward directed acadian thrusting in the long reach area of southern new brunswick a new stratigraphic succession has been delineated it consists of precambrian volcanic rocks cambrian sedimentary volcanic and hypabyssal rocks silurian sedimentary rocks and devonian plus precambrian heterogeneous granitoid rocks the northern boundary of this succession is postulated to be a northwestward directed thrust fault of acadian age other acadian thrust faults are interpreted in the area and major reverse movement of the same age occurred along the belleisle fault mafic and felsic volcanic rocks that were previously thought to be either precambrian or silurian are demonstrably part of the lower cambrian section some of the granitoid rocks intrude silurian strata and therefore cannot be basement to the cambrian succession other granitoid rocks appear to be older and may be precambrian in age

impacts of columbia river discharge on salmonid habitat 1 a nonstationary fluvial tide model 1 this is the first part of a two part investigation that applies nonstationary time series analysis methods and the st venant equations to the problem of understanding juvenile salmonid access to favorable shallow water habitat in a tidal river habitat access is a function of river stage tidal range and the distribution of bed elevation part 1 models nonstationary tidal properties species amplitudes and phases and tidal range part 2 models low frequency river stage in the lower columbia river and reconstructs historical water levels using the tidal model from part 1 to incorporate the nonstationary frictional effects of variable river discharge into the tidal model we decompose the tidal wave into tidal species and calculate daily tidal range our one dimensional tidal model is based on analytic wave solutions to the linearized st venant equation and uses six coefficients per tidal species to represent the upstream evolution of the frictionally damped tidal wave the form of the coefficients is derived from the st venant equations but their values are determined objectively from the data about 50 station years of surface elevation data collected 1981 2000 below bonneville dam 235 km from the ocean were processed with a wavelet filter bank to retrieve time series of tidal species properties a min max filter was used to estimate daily tidal range tidal range diurnal and semidiurnal amplitudes were predicted with mean root mean square errors 30 mm which is significantly more accurate than predictions obtained from harmonic analysis thus despite the compact form of our solution we model nonstationary fluvial tidal properties with a high level of accuracy

petrology and geochemistry of cambrian volcanic rocks from the avalon zone in new brunswick lower to middle cambrian volcanic rocks occur within the avalon zone of southern new brunswick at beaver harbour and in the long reach area the beaver harbour rocks are intensely altered but the major and trace element geochemistry indicates that they could be highly evolved basaltic andesites within plate basalts the mafic flows from the long reach area form two chemically and petrologically distinct groups 1 basalts with feldspar phenocrysts that represent evolved continental tholeiites with some oceanic characteristics and 2 a group of aphyric basalts showing extremely primitive continental tholeiite compositions also with oceanic affinities and resembling some rift related jurassic basalts on the eastern seaboard felsic pyroclastic rocks in the long reach area make the suite bimodal this distribution of rock types supports conclusions from the mafic rocks that the area experienced tension throughout the early to middle cambrian