patterns of turbulent and double diffusive phenomena observations from a rapid profiling microconductivity probe abstract throughout much of the ocean interior the diapycnal buoyancy flux is maintained by both mechanical and double diffusive processes assessing the relative roles of each is a challenge particularly in complex coastal environments during february march 1995 a repeat profiling ctd system equipped with a dual needle microconductivity probe was deployed off the central california coast 35 n 121 w from the research platform flip the probe s vertical resolution 8 cm appears sufficient to resolve the low wavenumbers of the turbulent inertial subrange this paper presents depth time maps spanning 12 days and 100 400 m of temperature dissipation rate and cox number high and values tend to occur in layers on a variety of spatial scales simultaneously finescale 6 4 m richardson number effective strain rate and turner angle are measured the occurrence of intense microstructure fluctuations is correlated with all three quantities affirming that both mechanical turbulence and d

statistical and hydrochemical methods to compare basalt and basement rock hosted groundwaters atherton tablelands north eastern australia multivariate analysis of physico chemical and chemical data has enabled differentiation among groundwaters sourced from different lithological formations in the atherton tablelands region of north eastern australia the main water resource is stored in basalt although basement rocks such as granite and metamorphics also contain variable amounts of water groundwater in the basalt is mostly mg ca na hco3 type with electrical conductivities less than 300 s cm and ph values from 6 5 to 8 5 some of the other groundwater is quite similar making the identification of hydrochemical facies difficult groundwater samples were grouped based on the results of a principal component factor analysis of the major dissolved constituents h4sio4 na ca2 mg2 and hco3 as well as ph and electrical conductivity based on this differentiation it was possible to identify the likely host rocks of groundwaters from unidentified lithological units define the basalt thickness and provide a better understanding of the groundwater resource principal component factor analysis has also been useful in identifying the likely hydrochemical processes controlling the composition of these groundwaters including the production of weak acids in the soil layers silicate mineral weathering ion exchange reactions evapotranspiration and the leaching of ions from organic matter supplementary material to this paper can be obtained by using the springer link server located at http dx doi org 10 1007 s00254 002 0667 z

origin of late archean granite geochemical evidence from the vermilion granitic complex of northern minnesota the 2 700 ma vermilion granitic complex of northern minnesota is a granite migmatite terrane composed of supracrustal metasedimentary rocks mafic rocks tonalitic and granodioritic plutonic rocks and granite the metasedimentary rocks are predominantly graywacke which has been regionally metamorphosed to garnet sillimanite muscovite bearing biotite schist and has locally undergone anatexis the mafic rocks form early phases within the complex and are of two types 1 basaltic amphibolite and 2 monzodiorite and essexite rich in large ion lithophile elements lile the members of the early plutonic suite form small bodies that intrude the metasedimentary rocks and mafic rocks producing an early migmatite the granite is of two distinct varieties 1 white garnet muscovite biotite leucogranite s type chappell and white 1974 and 2 grayish pink biotite magnetite lac la croix granite i type the leucogranite occurs in the early migmatite and in paragneissic portions of the complex whereas the lac la croix granite is a late stage intrusive phase that invades the early migmatite and metasediment producing a late migmatite and forms a batholith this study focuses specifically on the origin of granite in the vermilion granitic complex chemical mass balance calculations suggest that the s type two mica leucogranite had a metagraywacke source and that the i type lac la croix granite formed via partial fusion of calc alkaline tonalitic material which may have been similar to rocks of the early plutonic suite this model is satisfactory for petrogenesis of similar late archean post kinematic granites throughout the canadian shield

energy transport by nonlinear internal waves wintertime stratification on oregon s continental shelf often produces a near bottom layer of densefluid that acts as an internal waveguide on which nonlinear internal waves propagate shipboard profiling and bottom lander observations capture disturbances that exhibit properties of internal solitary waves bores and gravity currents wave like pulses are highly turbulent instantaneous bed stresses are 1 n m 2 resuspending bottom sediments into the water column and raising them 30 m above the seafloor the waves cross shelf transport of fluid counters the time averaged ekman transport in the bottom boundary layer in the nonlinear internal waves we have observed the kinetic energy is roughly equal to the available potential energy and is o 0 1 mj per m of coastline the energy transported by these waves includes a nonlinear advection term huei that is negligible in linear internal waves unlike linear internal waves the pressure velocity energy flux hupi includes important contributions from nonhydrostatic effects and surface displacement it is found that statistically huei 2hupi vertical profiles indicate that up z is more important in transporting energy near the seafloor while ue z dominates farther from the bottom with the wave speed c estimated from weakly nonlinear wave theory it is verified experimentally that the total energy transported by the waves hupi huei chei the high but intermittent energyflux by the waves is in an averaged sense o 100 w per m of coastline this is similar to independent estimates of the shoreward energy flux in the semidiurnal internal tide at the shelfbreak

retraction note the hydrochemical framework of surface water basins in southern ghana surface water resources play a crucial role in the domestic water delivery system in ghana in addition sustainable food production is based on the quality and quantity of water resources available for irrigation purposes to supplement rain fed agricultural activities in the country the objective of this research was to determine the main controls on the hydrochemistry of surface water resources in the southern part of ghana and assess the quality of water from these basins for irrigation activities in the area r mode factor and cluster analyses were applied to 625 data points from 6 river basins in southern ghana after the data had been log transformed and standardized for homogeneity this study finds that surface water chemistry in the south is controlled by the chemistry of silicate mineral weathering chemistry of rainfall fertilizers from agricultural activities in the area as well as the weathering of carbonate minerals a gibb s diagram plotted with total dissolved solids tds on the vertical axis against na k ca2 k na on the horizontal axis indicates that rock weathering plays a significant role in the hydrochemistry activity diagrams for the cao na2o al2o sio2 h2o and cao mgo al2o3 sio2 h2o systems suggest that kaolinite is the most stable clay mineral phase in the system in addition an assessment of the irrigation quality of water from these basins suggests that the basins are largely low sodium low to medium salinity basins delivering water of acceptable quality for irrigation purposes

the continental and oceanic crust and lithosphere in the archaean isostatic thermal and tectonic models simple isostatic models of the development of selected archaean basins and greenstone belts can be used to constrain models of the archaean lithosphere geophysical geochemical and thermal data imply that in southern africa the late archaean crust was probably comparable in thickness to the modern continental crust and the whole lithosphere was perhaps over 80 100 km thick two archaean belts studied may have developed by stretching of the order of 1 3 1 6 1 isostatic and thermal data and petrological assumptions allow the construction of simple models of the archaean oceanic lithosphere oceans were probably deep mid ocean ridges were probably subaqueous and fed by komatiitic liquids calc alkaline volcanism in the archaean may have been produced as a consequence of the subduction of hydrated komatiitic oceanic crust into a hot low viscosity asthensophere

lithophile elements in huronian low ti continental tholeiites from canada and evolution of the precambrian mantle abstract huronian basalts from central ontario canada dated at about 2450 ma and associated with an early rifting episode are classified as siliceous low ti nb tholeiites they display strong enrichment in large ion lithophile lile and light rare earth lree elements compared to modern oceanic lavas the tectonic setting and geochemistry resemble mesozoic rift related low ti flood basalts including the ferrar group of antarctica and the parana and equivalent etendeka volcanics of south brazil and namibia respectively high lile lree ratios are also similar to subduction related island arc tholeiites and it is suggested that enrichment of the huronian lithospheric mantle source occurred through ancient subduction of crustal material probably during formation and consolidation of the archean continental crust melting models suggest that huronian subcontinental mantle source compositions derived from least contaminated aphyric mafic end members had already undergone a complex evolution including withdrawal of archean basalts and hydrous enrichment in incompatible components despite several subsequent melting episodes and a second probably magmatic enrichment event however many aspects of the huronian source signature were preserved and appeared in later basaltic products of this mantle mass keweenawan volcanics for example dated at about 1100 ma preserve low p zr ti and hree abundances

observations of large amplitude mode 2 nonlinear internal waves on the australian north west shelf abstractlarge amplitude mode 2 nonlinear internal waves were observed in 250 m deep water on the australian north west shelf wave amplitudes were derived from temperature measurements using three

modal response of reservoirs to wind stress an analysis of the response of a density stratified reservoir to surface shear stress is presented the reservoir is assumed to be two dimensional and to have a constant depth in the limit that the bulk wedderburn number wb and the bulk richardson number rib are both infinite the resulting equations are linear and solutions can be found in terms of the individual responses of a set of orthogonal normal modes for the case of a steady wind stress the solution consists of periodic motions and steady isopycnal displacements however the steady state isopycnal slope at the base of the mixed layer is infinite implying that upwelling can occur when the wedderburn number is quite large this is attributed to blocking of the stratified fluid below the mixed layer by the endwall the modal theory presented in this paper is compared with experimental observations made using a belt to impart shear stress to a stratified fluid contained in a box the comparison shows that the present theory is qualitatively corr

uranium anomaly evaluation in groundwaters a hydrogeochemical study in the nisa region portugal abstract the hydrogeochemistry of the nisa region central portugal an area of known u mineralization was studied the geology of the region comprises an s type high level granite intrusion with vein type u mineralization its contact metamorphic aureole developed in a schist host rock containing disseminated u mineralization an integrated multi variate statistical hydrogeochemical and thermodynamic approach was adopted for the interpretation of groundwater data from the granite and its contact aureole the u groundwater anomalies are evaluated within the local hydrogeochemical context one hundred and fifteen water samples were collected and analyzed for ph ec eh na k ca mg fe mn al u li ba sr cl hco 3 so 4 no 3 po 4 f doc and h 4 sio 4 uni and bi variate statistical studies of these dilute waters indicate that mainly surface and land use characteristics control the dominant chemical processes with water rock interaction playing a lesser role granite schist compositional differences show up especially in the mg and hco 3 content of the waters multi variate statistical analyses principal component analysis and q mode cluster analysis were carried out separately on the granite and schist water groups evapotranspiration is an important process both in the schist and granite environment the impact of fault fracture zones land use oxidation reduction reactions and water rock interaction is different for the waters from each bedrock type for both rock types the waters can be classified into genetic groups or clusters ranging from surface runoff shallow interflow through surface agriculture and infiltrated to village pollution type water the distribution pattern of these groundwater types is not disrupted by the granite schist contact allowing for an interpretation of the u distribution in the entire study area thermodynamic calculations indicate that the predominant u species in solution is uo 2 hpo 4 2 2 virtually all waters are undersaturated with respect to u minerals the distribution of u in the waters is thus not influenced by precipitation of u bearing minerals the distribution of u in the water samples as well as that for u ec in an attempt to correct for evapotranspiration are evaluated the u and u ec anomaly patterns are considerably biased by bedrock differences and varying genetic history interpretability is greatly improved if these differences are taken into account by defining u threshold values for each genetic water cluster all known radiometric anomalies are reflected in the hydrogeochemical u anomaly pattern the general hydrogeochemical features allow for a refined evaluation of the known radiometric anomalies and of the additional anomalies found in the present study additional hydrogeochemical anomalies from waters reflecting depth characteristics are attractive exploration targets

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

high frequency internal waves on the oregon continental shelf abstract measurements of vertical velocity by isopycnal following neutrally buoyant floats deployed on the oregon shelf during the summers of 2000 and 2001 were used to characterize internal gravity waves on the shelf using measurements of vertical velocity the average spectrum of wentzel kramers brillouin wkb scaled vertical kinetic energy has the level predicted by the garrett munk model gm79 plus a narrow m2 tidal peak and a broad high frequency peak extending from about 0 1n to n and rising a decade above gm79 the high frequency peak varies in energy coherently with time across its entire bandwidth its energy is independent of the tidal energy the energy in the continuum region between the peaks is weakly correlated with the level of the high frequency peak energy and is independent of the tidal peak energy the vertical velocity is not gaussian but is highly intermittent with a calculated kurtosis of 19 the vertical kinetic energy varies geographically low energy is found offshore and

the scourie dyke suite petrogenesis and geochemical nature of the proterozoic sub continental mantle the petrogenesis of bronzite picrite olivine gabbro norite and quartz tholeiite dykes which make up the 2 39 b y scourie dyke swarm cutting the archaean lewisian gneisses of n w scotland is interpreted on the basis of their major and trace element geochemistry most of the dykes bear primary amphibole and or phlogopite and with one exception are all hypersthene or quartz normative apart from one tholeiite dyke which shows relative light rare earth element depletion all the dykes show enrichment in light rare earths and large ion lithophile elements they do not however show an equivalent enrichment in other incompatible high field strength ions such as nb and ta and in this respect resemble island arc and calc alkaline basalts the different dyke types have distinctive rare earth patterns and other trace element ratios which are maintained over a range of major element compositions

phosphorus and the rare earth elements in felsic magmas an assessment of the role of apatite abstract the solubility of fluorapatite in 17 silica rich melts in the system na 2 o k 2 o al 2 o 3 sio 2 with and without cao or caf 2 was determined at 1 kbar water pressure and 750 900 c apatite saturation occurs at levels of dissolved p 2 o 5 ranging between 0 04 0 02 and 0 28 0 13 wt with only 4 values outside the 0 09 0 20 wt range the results demonstrate not only that apatite is a common liquidus phase in felsic melts but also that under most circumstances it remains in the residue during episodes of partial fusion of the crust given a solubility limit of 0 14 wt dissolved p 2 o 5 the mean of the experimental values a source containing as little as 0 05 p 2 o 5 must be 35 melted before apatite is lost from the residue and no longer buffers the melt p 2 o 5 concentration at the saturation value higher abundances of p 2 o 5 in the source postpone the loss of residual apatite to still higher degrees of melting and if the source p 2 o 5 content exceeds 0 14 wt apatite must be residual for all degrees of melting increasing in abundance as melting proceeds the generally secondary influence of apatite on the rare earth element ree patterns of melt and residue is most apparent when garnet and or amphibole is minor or lacking in the residue fractional crystallization of intermediate e g andesitic magmas toward felsic compositions invariably results in saturation in apatite and some consequent depletion of ree in the melt

use of statistical analysis to formulate conceptual models of geochemical behavior water chemical data from the botucatu aquifer in sao paulo state brazil water chemical data from the botucatu sandstone aquifer in the sao paulo state part of the parana basin brazil was evaluated using geochemical methods and two statistical analyses cluster analysis and factor analysis the results were used to develop a conceptual geochemical model in which three geochemical regions were identified and their chemical behavior was modeled the characteristic chemicals changing from the recharge area to the center of the basin are sio2 hco3 and ca2 na co32 and so42 the distribution of the chemicals is interpreted as controlled by different water rock interaction processes in the different regions in the recharge area dissolution of alkali feldspar minerals in the sandstone is the main reaction observed in the mid section of the basin calcite dissolution results in high calcium and bicarbonate concentration in the center of the basin leakage from underlying layers becomes the governing factor

very large subaqueous sand dunes on the upper continental slope in the south china sea generated by episodic shoaling deep water internal solitary waves abstract very large subaqueous sand dunes were discovered on the upper continental slope of the northern south china sea the dunes were observed along a single 40 km long transect southeast of 21 93 n 117 53 e on the upper continental slope in water depths of 160 m to 600 m the sand dunes are composed of fine to medium sand with amplitudes exceeding 16 m and crest to crest wavelengths exceeding 350 m the dunes apparent formation mechanism is the world s largest observed internal solitary waves which generate from tidal forcing on the luzon ridge on the east side of the south china sea propagate west across the deep basin with amplitudes regularly exceeding 100 m and dissipate extremely large amounts of energy via turbulent interaction with the continental slope suspending and redistributing the bottom sediment while subaqueous dunes are found in many locations throughout the world s oceans and coastal zones these particular dunes appear to be unique for two principal reasons their location on the upper continental slope away from the influence of shallow water tidal forcing deep basin bottom currents and topographically amplified canyon flows and their distinctive formation mechanism approximately 60 episodic extremely energetic large amplitude events each lunar cycle

application of multivariate statistical methods and inverse geochemical modeling for characterization of groundwater a case study ain azel plain algeria abstract multivariate statistical methods and inverse geochemical modeling were jointly used to define the variation and the genetic origin of chemical parameters of groundwater in the ain azel plain algeria interpretation of analytical data shows that the abundance of the major ions is as follows ca mg na k and hco 3 cl so 4 q mode hierarchical cluster analysis hca was employed for partitioning the water samples into hydrochemical facies also known as water groups or water types three major water groups resulted from the hca analysis the samples from the area were classified as recharge area waters group 1 ca mg hco 3 water transition zone waters group 2 ca mg cl hco 3 water and discharge area waters group 3 mg ca hco 3 cl water inverse geochemical models of the statistical groups were developed using phreeqc to elucidate the chemical reactions controlling water chemistry the inverse geochemical modeling demonstrated that relatively few phases are required to derive water chemistry in the area in a broad sense the reactions responsible for the hydrochemical evolution in the area fall into three categories 1 dissolution of evaporite minerals 2 precipitation of carbonate minerals and 3 weathering reactions of silicate minerals

internal tidal mixing as a control on continental margin ecosystems we show that a breaking internal tide at a shelf edge is a fundamental control on the structural and functional properties of ecosystems contrasts in vertical mixing of nitrate between the shelf and the open ocean correspond with horizontal and vertical changes in phytoplankton communities with largest cells found in surface waters at the shelf edge intense fishing activity is commonly seen at continental shelf edges targeting spawning fish stocks we suggest that the internal tide a globally ubiquitous physical process at steep shelf edge bathymetry supports shelf edge fisheries by providing large celled phytoplankton for first feeding fish larvae the repeatability of the internal tide removes fish from the need to time spawning with a spring bloom also with large phytoplankton cells dominating particulate organic carbon export the internal tides could be an important influence on spatial and temporal variability in patterns of global carbon sequestration in deep water and sediments citation sharples j c m moore a e hickman p m holligan j f tweddle m r palmer and j h simpson 2009 internal tidal mixing as a control on continental margin ecosystems geophys res lett 36 l23603 doi 10 1029 2009gl040683

a geochemical study of the impact of irrigation and aquifer lithology on groundwater in the upper yakima river basin washington usa the yakima river a major tributary of the columbia river is currently overallocated in its surface water usage in part because of large agricultural water use as a result groundwater availability and surface water groundwater interactions have become an important issue in this area in several sub basins the yakima river water is diverted and applied liberally to fields in the summer creating artificial recharge of shallow groundwater major ion trace element and stable isotope geochemistry of samples from 26 groundwater wells from a transect across the yakima river and 24 surface waters in the kittitas sub basin were used to delineate waters with similar geochemical signatures and to identify surface water influence on groundwater major ion chemistry and stable isotope signatures combined with principal component analysis revealed four major hydrochemical groups one of these groups collected from shallow wells within the sedimentary basin fill displays temporal variations in no3 and so4 along with high 18o and d values indicating significant contribution from yakima river and or irrigation water two other major hydrochemical groups reflect interaction with the main aquifer lithologies in the basin the columbia river basalts high na groundwaters and the volcaniclastic rocks of the ellensburg formation ca mg hco3 type waters the fourth major group has interacted with the volcaniclastic rocks and is influenced to a lesser degree by surface waters the geochemical groupings constrain a conceptual model for groundwater flow that includes movement of water between underlying columbia river basalt and deeper sedimentary basin fill and seasonal input of irrigation water

exploration of groundwater flowpaths and effective recharge in the amargosa desert nevada using multivariate statistical analysis and elevation dependent chloride mass balance method estimation of groundwater flowpaths and effective recharge was performed in the vicinity of amargosa desert nevada usa using multivariate statistical methods msms and a simple elevation dependent chloride mass balance method modified by estimating a minimum effective recharge elevation mere msms were applied to major ion data to explain the relationships among different groundwater chemical species define hydrochemical facies needed to determine groundwater flowpaths and evolution and identify the influence of surface and geologic features on groundwater for each defined watershed an average groundwater chloride concentration is used and the chloride deposition rate is assessed in the subject watersheds over all land elevations above the estimated mere by assuming two constant spatial and temporal concentrations of chloride in precipitation which is a function of elevation the mere for the amargosa desert was appraised as 1200 m above mean sea level m amsl based upon the elevation of the orifice of cane spring 1237 m amsl one of the lowest elevation permanent springs on the nevada national security site this minimum elevation is the cutoff altitude for our calculations at which precipitation is considered to make a significant contribution to recharge elevation dependent precipitation was evaluated relating elevation data from the online mapping software acme labs mapper 2 1 and precipitation data from the prism climate group s prism these analyses provide further insight into the hydrology of the region and demonstrate the strong impact surface and geologic features can have on surface water infiltration and groundwater in arid regions specifically evidence is presented of past focused recharge around the ephemeral fortymile wash and interaction between geologic faults and groundwater infiltration and flowpaths in addition groundwater flow based upon water chemistry appears to be segmented by major faults groundwater recharge in the vicinity of the amargosa desert has been estimated around 15 280 acre ft year

tidally forced internal waves and overturns observed on a slope results from home abstract tidal mixing over a slope was explored using moored time series observations on kaena ridge extending northwest from oahu hawaii during the survey component of the hawaii ocean mixing experiment home a mooring was instrumented to sample the velocity and density field of the lower 500 m of the water column to look for indirect evidence of tidally induced mixing and was deployed on a slope in 1453 m water depth for 2 months beginning in november 2000 the semidiurnal barotropic tidal currents at this site have a significant cross ridge component favorable for exciting an internal tidal response a large amplitude response is expected given that the slope of the topography 4 5 is nearly the same as the slope of the internal wave group velocity at semidiurnal frequency density overturns were inferred from temperature profiles measured every 2 min the number and strength of the overturns are greater in the 200 m nearest the bottom with overturns exceeding 24 m present at any depth nearly

human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use schot p p and van der wal j 1992 human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use j hydrol 134 297 313 the relations between groundwater composition land use soil conditions and flow patterns on a regional scale are studied for the gooi and vechtstreek area in the netherlands this densely populated area consists of a glacier created ridge with dry sand soils bordered by the vecht and eem river plains with wet peat and clay soils r mode factor analysis and q mode cluster analysis were applied to a set of 1349 groundwater analyses to determine the factors controlling groundwater composition and the main resulting water types the results indicate that groundwater composition in the study area is affected on a regional scale by human activities through changes in land use and intervention in natural flow patterns on the ridge ground water is recharged by precipitation which dissolves carbonates from the matrix of the sandy aquifer increased solute concentrations in shallow ground water especially of nitrate sulphate and potassium indicate increased pollution resulting from urbanization and increasingly intensive agricultural activity over the past decades in the vecht river plain infiltration occurs as a result of drainage of polders and groundwater extraction on the ridge recharge occurs by precipitation and from polluted surface water to which ammonium organic complexes and carbonic acid are added through decomposition of organic matter in the peat and clay soils the carbonic acid results in enhanced dissolution of carbonates present in the soil and the underlying sandy aquifer oxygen depletion and subsequent low redox potentials result in denitrification dissolution of manganese and iron oxides and sulphate ro duction the flow of ground water from high level to low level polders causes displacement of a former stagnant brackish groundwater body under the vecht river plain accompanied by increased mixing of fresh and brackish ground water

archaean basic volcanism in the eastern goldfields province yilgarn block western australia abstract petrographic petrological and geochemical studies have demonstrated the presence of three distinctive basic volcanic suites in the eastern goldfields province yilgarn block western australia these are termed the high magnesian series basalts hmsb the low magnesian series basalts lmsb and the siliceous high magnesian series basalts shmsb the hmsb and shmsb constitute differentiation series which contain both high mgo 9 5 14 wt and low mgo the hmsb and lmsb were derived from source mantle regions which were variably depleted in the incompatible elements archaean komatiites were derived from similarly depleted source regions and it is argued that the main petrogenetic difference between these three volcanic suites was the degree of partial melting from which they were derived the depleted nature of the source regions may have been induced by earlier small degree source mantle regions of the shmsb were variably enriched in the incompatible elements and water and parental magmas of the shmsb were derived from moderately hydrous conditions of partial melting the relative proportions of each basalt suite varies considerably between the layered successions examined for example the basic volcanics overlying the komatiites at kambalda are shmsb while the footwall volcanics consist predominantly of hmsb with subordinate lmsb however the norseman succession where no ultramafic volcanics are known to occur is comprised mainly of lmsb with a smaller proportion of hmsb

multivariate statistical analysis for the assessment of groundwater quality under different hydrogeological regimes multivariate statistical analysis has been widely used for hydrogeochemical characterization of groundwater quality in this study hydrochemical data from three hydrological basins were used and two methods factor and cluster analyses were applied the first area is the coastal area of eastern thermaikos gulf where groundwater is influenced by seawater intrusion and geothermal fluids the other two areas are the inland basins of gallikos and perdikas in which agricultural and industrial activities constitute the main anthropogenic pollution sources of groundwater initially the aforementioned methods were applied for each area separately and resulted in a different number of significant factors and clusters while the natural and anthropogenic influences were spatially determined in each area additionally factor and cluster analyses were applied coupling data from all areas therefore five clusters and three major factors were determined distinguishing the hydrochemical processes and impacts from anthropogenic activities in more detail it is worth mentioning that the application of cluster analysis in the coupled groundwater samples of all studied areas resulted beneficially in the most hydrochemically complex area salinization dominates in the coastal area while in gallikos and perdikas basins high concentrations of no3 occur mainly due to agricultural activities and small livestock units the numerous hydrochemical samples are identified as the main issue for the higher discretization and reliability of the second approach nevertheless this study is associated with a number of limitations of multivariable statistical analysis regarding extreme concentrations of cl and na this issue stimulates further research in overcoming and understanding these drawbacks

geochemical stratigraphy of the huronian continental volcanics at thessalon ontario contributions of two stage crustal fusion the 1500 m thick sequence of huronian continental volcanics at thessalon ontario is subdivided into 4 volcanic cycles each of which includes abundant early mafic end members central intermediate flows and late rhyolite units major and trace element concentrations are dominated by extensive gabbroic fractionation trends that ultimately produced two types of felsic flows 1 rhyolites with high light rare earth element lree and relatively low large ion lithophile element lile concentrations high lree low lile rhyolites and 2 following late separation of ree rich accessory phases rhyolites depleted in lree low lree high lile rhyolites mafic end members of individual volcanic cycle are progressively less siliceous and less enriched in lile and lree with height in the stratigraphic section ti zr ratios gradually rise from 35 in early mafic flows to stabilize at about 85 in late units while average sio2 contents decrease from 56 to about 50 and mg rises from about 48 to 52 nd values are consistently negative indicating variable degrees of pre fractionation crustal contamination of the end member magmas during their uprise through the crust mixing models are consistent with up to 50 contamination by crustal material of tonalitic hornblende gneiss composition a progressive increase in nd from about 5 0 to 0 5 upward in the volcanic succession reflects a decreasing degree of crustal contamination due to development of insulating layers along margins of the feeder system detailed stratigraphic variations suggest that successive magmas batches were intercepted by a progressively fractionating periodically replenished magma source giving rise to open system magmatism despite the prevalence of crustal assimilation in the huronian lavas la sr n ratios are too low in least contaminated end members to be explained by contamination of tholeiitic magmas the late basalts resemble instead modern island are basalts and it is suggested that the subcontinental mantle source was enriched by subduction related processes during crustal formation within individual volcanic cycles gabbroic fractionation trends systematically deviate from calculated factors toward compositions characteristic of hornblende gneiss such relations suggest that further crustal contamination of the magmas occurred simultaneous with crystal fractionation probably within undulating sills at upper crustal levels quantitative analysis suggests assimilation fractional crystallization a fc ratios of about 0 45 as a result of extensive two stage contamination rhyolites from the initial volcanic cycle incorporate a total of over 60 of crust

internal solitary waves with subsurface cores large internal solitary waves with subsurface cores have recently been observed in the south china sea here fully nonlinear solutions of the dubreil jacotin long equation are used to study the conditions under which such cores exist we find that the location of the cores either at the surface or below the surface is largely determined by the sign of the vorticity of the near surface background current the results of a numerical simulation of a two dimensional shoaling internal solitary wave are presented which illustrate the formation of a subsurface core

geochemical evolution of groundwater in a basaltic aquifer based on chemical and stable isotopic data case study from the northeastern portion of serra geral aquifer sao paulo state brazil summary groundwater from the fractured basalt serra geral aquifer sga represents an important source for water supply in northeastern sao paulo state brazil groundwater flow conditions in fractured aquifers hosted in basaltic rocks are difficult to define because flow occurs through rock discontinuities the evaluation of hydrodynamic information associated with hydrochemical data has identified geochemical processes related to groundwater evolution observed in regional flowpaths sga groundwaters are characterized by low tds with ph varying from neutral to alkaline two main hydrochemical facies are recognized ca mg hco 3 and na hco 3 types primarily the geochemical evolution of sga groundwater occurs under co 2 open conditions and the continuous uptake of co 2 is responsible for mineral dissolution producing bicarbonate as the main anion and calcium and magnesium in groundwater ion exchange between smectites na and ca beidelites seems to be responsible for the occurrence of na hco 3 groundwater toward the rio grande in the northern portion of the study area there is mixing between sga groundwater and water from the sandstones of the guarani aquifer system as evidenced by the chemical and isotopic composition of the groundwater inverse mass balance modeling performed using netpath xl produces results in agreement with the dissolution of minerals in basalt feldspars and pyroxenes associated with the uptake of atmospheric co 2 as well as the dissolution of clay minerals present in the soil kaolinite precipitation occurs due to the incongruent dissolution of feldspars while si remains almost constant due to the precipitation of silica the continuous uptake of co 2 under open conditions leads to calcite precipitation which in addition to ion exchange are responsible by ca removal from groundwater and an increase in na concentrations down the flow gradientco 2 is subject to closed conditions where the basalts are covered by the sediments of bauru group or associated with deeper isolated discontinuities a decrease in the amount of dissolution of labradorite and augite is observed associated with precipitation of carbonates and kaolinite stable isotope ratios of sga groundwater vary from 37 8 to 61 3 vsmow for 2 h vsmow and 5 7 to 8 9 vsmow for 18 o indicating temporal variations in climatic conditions during recharge

application of multivariate statistical procedures on major ions and trace elements in a multilayered coastal aquifer the case of the south rhodope coastal aquifer multivariate statistical techniques including cluster analysis and principal components analysis were applied on 22 variables consisted of 3 physicochemical parameters 8 major ions and 11 trace elements samples were collected from the south rhodope multilayered coastal aquifer in north greece which is facing saltwater intrusion and anthropogenic contamination over the last 35 years cluster analysis grouped the variables into five main groups while principal components analysis revealed four distinct hydrochemical processes in the aquifer system explaining 84 5 of the total variance between the variables the identified processes correspond to saltwater intrusion and subsequent reverse cation exchange the presence of deep connate groundwater masses application of fertilizers in shallow wells and anthropogenic contamination with heavy metals nearby an improperly constructed landfill the wells categorized with the above techniques were grouped and five constituent ratios na cl mg ca cl ca hco3 so4 ca so4 and ca mg were utilized to identify the ones which enable the more accurate distinction between the group cases the results of stepwise discriminant analysis showed that the calculated classification function can distinguish almost 80 of groundwater samples with the na cl ratio being the most statistically significant grouping variable all the aforementioned statistical models managed to successfully identify numerous hydrochemical processes in a complex multilayered aquifer system and to explicitly attribute them for every investigated well allowing a deeper insight into groundwater chemical characteristics with the use of an optimized smaller number of variables

internal solitons on the pycnocline generation propagation and shoaling and breaking over a slope in part 1 a study is made of the internal solitary wave on the pycnocline of a continuously stratified fluid a korteweg de vries kdv equation for the interfacial displacement is developed following benney s method for long nonlinear waves experiments were conducted in a long wave tank with the pycnocline at several different depths below the free surface while keeping the total depth approximately constant a step like pool of light water trapped behind a sliding gate served as the initial disturbance condition the number of solitons generated was verified to satisfy the prediction of inverse scattering theory the fully developed soliton was found to satisfy the kdv theory for all ratios of upper layer thickness to total depth in part 2 of this study we investigate experimentally the evolution and breaking of an internal solitary wave as it shoals on a sloping bottom connecting the deeper region where the waves were generated to a shallower shelf region it is found through quantitative measurements that the onset of wave breaking was governed by shear instability which was initiated when the local gradient richardson number became less than the internal solitary wave of depression was found to steepen at the back of the wave before breaking in contrast with waves of elevation two slopes were used with ratios 1 16 and 1 9 and the fluid was a boussinesq fluid with weak stratification using brine solutions

hydrogeological and hydrochemical characterization of the voltaian basin the afram plains area ghana in the afram plains area groundwater is the main source of water supply for most uses the area is underlain by aquifers of the southern voltaian sedimentary basin which are predominantly sandstones mudstones conglomerates and shale ordinary least squares regression analysis using 41 well test data from aquifers in the afram plains portion of the voltaian system reveals that transmissivity t exists in a non linear relationship with specific capacity sc the analysis reveals that t 0 769sc1 075 with r 2 0 83 for aquifers in the area the mudstone conglomerate aquifer in the area appears to be the most variable in terms of both specific capacity and transmissivity with transmissivity ranging from 0 18 to 197 7 m2 day and 0 5 and 148 5 m3 day m respectively horizontal fractures and joints resulting from secondary fracturing appear to be the main determinants of both transmissivity and specific capacity in the area phreeqc modeling and mineral stability diagrams indicate that groundwater quality in the afram plains area is controlled by the incongruent weathering of silicate minerals in the aquifers these processes concentrate calcium sodium magnesium potassium bicarbonate ion and quartz leading to calcite dolomite and aragonite supersaturation at most locations hierarchical cluster analysis performed on the raw chemical data reveals two main water types or facies the calcium sodium chloride bicarbonate facies and the magnesium potassium sulfate nitrate facies for the southern and northern sections of the afram plains area respectively

geology and geochemistry of huronian rhyolites and low ti continental tholeiites from the thessalon region central ontario bimodal volcanism associated with early phases of huronian rifting in central ontario dated about 2450 ma produced low ti tholeiitic basalts and two varieties of crustally derived calc alkaline rhyolite early tholeiites are characteristically highly evolved have mg values from 30 to 50 and display pronounced enrichment in large ion lithophile elements lile and light rare earth element lree in comparison with modern oceanic basalts fractionated heavy rare earth element hree patterns and low ti zr p nb ba and k abundances ti zr ratios rise progressively in early basalts and associated basaltic andesite fractionates from about 35 in early flows to 55 in central units late basalts also carry enriched lile and lree but in contrast to early types have average mg values greater than 50 and lower rare earth element ree abundances with flat hree patterns they also display negative ba nb and p anomalies on chondrite normalized distribution diagrams but lack low k zr and ti contents

retracted article application of multivariate statistical methods and geochemical modeling to evaluate the surface water of timgad basin east algeria after careful investigation carried out in accordance with the cope guidelines the editor in chief and the publisher have decided to retract this article the text shows significant unattributed overlap with the following articles tiri ammar noureddine lahbari and abderrahmane boudoukha hydrochemical characterization of surface water in the timgad watershed east algeria desalination and water treatment 2014 tiri ammar noureddine lahbari and abderrahmane boudoukha assessment of the quality of water by hierarchical cluster and variance analyses of the koudiat medouar watershed east algeria applied water science 2015 belkhiri l statistical categorization geochemical modeling of groundwater in ain azel plain algeria journal of african earth sciences 201101 belkhiri l application of multivariate statistical methods and inverse geochemical modeling for characterization of groundwater a case study ain azel plain algeria geoderma 20101115 vikram bhardwaj hydrogeochemistry of groundwater and anthropogenic control over dolomitization reactions in alluvial sediments of the deoria district ganga plain india environmental earth sciences 01 2010 li peiyue hydrochemical formation mechanisms and quality assessment of groundwater with improved topsis method in pengyang county northwest china e journal of chemistry 2011

early ordovician continental break up in variscan europe ndsr isotope and trace element evidence from bimodal igneous associations of the southern massif central france abstract the high grade marvejols group and the low grade albigeois cevennes sedimentary sequence contain bimodal igneous rocks of early ordovician age which are representative of a widespread thermal event in the european variscides comparison of their nd sr isotope and trace element characteristics provides additional evidence for their origin in an ensialic extensional setting as an alternative to the back arc model proposed by previous authors we propose that these associations record a continental break up episode unrelated to contemporaneous subduction in this model the widespread early paleozoic bimodal magmatism marks the birth of a mid european oceanic arm we propose that the break up was controlled by both transtensional processes and mantle plume activity high grade associations such as the marvejols group and low grade bimodal associations such as the albigeois cevennes might be regarded as representing opposite rifted passive margins the northern marvejols type margin was involved in a late ordovician silurian subduction like process with hp ht metamorphism in contrast the southern albigeois cevennes margin remained largely unaffected possibly as part of the overriding plate of the subduction zone pseudo calc alkaline signatures unrelated to subduction processes may occur in magmatic rocks associated with continental break up episodes in this case negative nb anomalies are produced by the addition of crustal components enriched in th and lree relative to nb this inferred alternative origin of nb anomalies has important bearing on the paleogeodynamic settings based on geochemical data

geochemical changes recorded in lynch s crater northeastern australia over the past 50 ka there are many geochemical reconstructions of environmental change in the mid and high latitudes but relatively few in the tropical latitudes despite their considerable potential for reconstructing environmental processes that cannot be identified using more traditional proxies here we present one reconstruction of environmental change for the tropics this reconstruction covers the past 50 ka using a suite of geochemical data from the high resolution sequence of lynch s crater in northeast queensland australia a region highly sensitive to el nino southern oscillation enso activity the 23 major oxides and trace elements measured could be summarised by extracting three axes using principal components analysis accounting for 72 of the variability the data indicate that the greatest variability in the geochemical data accounted for erosional activity within the catchment that was associated with past changes in the frequency of enso activity though this was less sensitive during wetter periods probably as a result of buffering by high vegetation cover the remaining variability was largely explained by elements that form complexes with organic compounds e g humic acids and those that are important nutrients for specific vegetation types and therefore a measure of vegetation distribution for more detailed reconstructions further work is required to disentangle the complex controls of clements within sedimentary sequences c 2005 elsevier b v all rights reserved

internal wave weather in a stratified lake thermistor chain data collected in lake biwa japan during a period of strong stratification were used to determine the nature of the water column response to wind forcing the evolution of the basin scale waves in the lake were reproduced in three dimensional numerical simulations and the time variability of the internal wave spectrum is discussed based on spectral analysis of the thermistor chain records severe winds associated with the passage of three typhoons during the sampling period excited basin scale kelvin and poincare waves which by interaction with the topography of the lake and non linear effects generate trains of high frequency internal waves time frequency analysis of the temperature signals suggests that the 2 slope of the internal wave spectrum is probably the result of the composition of groups of waves with high intermittence travelling through the wave guide the observed rapid decay of internal wave energy after severe wind events seemed to be due mostly to high dissipation at the sloping boundaries of the lake

structure propagation and mixing of energetic baroclinic tides in mamala bay oahu hawaii abstract large semidiurnal vertical displacements 100 m and strong baroclinic currents 0 5 m s 1 several times as large as barotropic currents dominate motions in mamala bay outside the mouth of pearl harbor hawaii during september 2002 the authors sought to characterize them with a 2 month mclane moored profiler deployment and a 4 day intensive survey with a towed ctd adcp and the research vessel r v revelle hydrographic sonar spatial maps and time series of turbulent dissipation rate diapycnal diffusivity k isopycnal displacement velocity u energy e and energy flux f are presented dissipation rate peaks in the lower 150 m during rising isopycnals and high strain and shows a factor of 50 spring neap modulation the largest k values in the western bay near a submarine ridge exceed 10 3 m2 s 1 the m2 phases of and u increase toward the west implying a westward phase velocity cp 1 m s 1 and horizontal wavelength 60 km consistent with theoretical mode 1 values these phase

physical properties of turbulent benthic boundary layers generated by internal waves physical properties of active turbulent benthic boundary layers tbbl generated by basin scale internal waves were studied within a northern hemisphere thermally stratified lake a microstructure profiler was used to measure the nature of the turbulence within the tbbls while a series of thermistor chains were used to monitor the thermal structure of the lake it was observed that a wind driven anticlockwise diurnal period vertical mode one kelvin wave generated large scale motions within the water column and that the interactions between this wave and the sloping lakebed induced tbbls a simple model based on potential energy change and boundary shearing was shown to describe the mean tbbl thickness

a u pb age for mineralized nipissing diabase gowganda ontario concordant baddeleyite and rutile analyses from mineralized nipissing diabase at gowganda s castle mine yield a u pb age of baddeleyite is a primary phase of the diabase therefore the age dates the magmatic emplacement the genesis of rutile is less certain rutile could have formed during an episode of alteration veining and ag mineralization in which case the u pb age would also date the secondary event and demonstrate that ag mineralization was related to the nipissing magmatism however a primary magmatic origin of the rutile cannot be completely excluded for now thus the u pb age may not constrain the time of ag mineralization further research is needed to clarify this point

observations of highly nonlinear internal solitons over the continental shelf surface disturbances caused by strong near surface internal waves are widely seen in coastal regions as bands of slick and rough water propagating shoreward these surface slicks are typically manifestations of optical and radar backscatter properties above internal solitons and have strong surface current pulses associated with them during a recent experiment studying coastal internal waves extremely strong solitary internal wave packets were observed over a three week period on a very shallow and strongly stratified pycnocline off northern oregon during periods of strongest tidal forcing solitons were consistently observed on the leading edge of a semidiurnal internal tide bore with pycnocline displacements up to 25m downward from a 7m initial depth in the first few solitons the extreme nonlinearity of these internal waves is believed to be unique in ocean observations this note characterizes these highly nonlinear solitary internal waves siw and presents a second order kdv model which reproduces the form of the displacements and the small change in soliton width with amplitude predicted by this model

numerical investigation of solitary internal wave induced global instability in shallow water benthic boundary layers abstract the time dependent boundary layer induced by a weakly nonlinear solitary internal wave in shallow water is examined through direct numerical simulation waves of depression and elevation are both considered the mean density field corresponds to that typical of the coastal ocean and lakes where the lower fraction of the water column is subject to the stabilizing effect of a diffuse stratification sufficient resolution of the inviscid dynamics of the boundary layer is ensured through use of a legendre spectral multidomain discretization scheme in the vertical direction at higher reynolds numbers where the simulations become underresolved because of restrictions in available computational resources spectral accuracy and numerical stability at the scales of physical interest are preserved through use of a penalty scheme in the vertical and explicit spectral filtering thus a highly accurate description of the qualitative dynamics of the wave induced global instability is possible and finesca

pre emplacement re os ages from ultramafic inclusions in the sublayer of the sudbury igneous complex ontario abstract re os isotope analyses have been performed on a suite of 14 melanorite inclusions from the sublayer of the sudbury igneous complex sic at whistle mine 30 km nne of sudbury ontario canada six s poor olivine melanorites have relatively unradiogenic present day 187 os 188 os ratios of 0 16 1 2 and define an imprecise age of 1 97 ga their 187 os 188 os 1 85 ratios of 0 107 0 237 are compatible with derivation either from the mantle at the time of sic formation 1 85 ga ago or from pre existing crustal rocks with low re os ratios and unradiogenic os isotope compositions in contrast the relatively s rich inclusions define much older ages of 2 46 ga melanorites and 2 67 ga olivine melanorites while 187 os 188 os 1 85 ratios of 0 41 1 80 unequivocally demonstrate that their os was largely derived from pre existing crustal lithologies the os isotope compositions and s abundances of the inclusions are consistent with mixing at 1 85 ga between an unradiogenic silicate fraction defined by the s poor suite and a radiogenic sulphide rich component with re os ratios similar to those of pre existing crustal lithologies attempts to evaluate the source of the ni cu s and pge in the sic through mass balance calculations are not definitive because of the difficulties in estimating accurately both present day and pre sic crustal abundances however crude estimates suggest that the overall levels of ni and cu in the pre impact crust were probably sufficient to account for the budget of these elements in the present day sic but do not rule out the possibility of significant late archaean early proterozoic sulphide mineralisation in the pre existing sic target rocks

simulation of the transformation of internal solitary waves on oceanic shelves abstract internal solitary waves transform as they propagate shoreward over the continental shelf into the coastal zone from a combination of the horizontal variability of the oceanic hydrology density and current stratification and the variable depth if this background environment varies sufficiently slowly in comparison with an individual solitary wave then that wave possesses a soliton like form with varying amplitude and phase this stage is studied in detail in the framework of the variable coefficient extended korteweg de vries equation where the variation of the solitary wave parameters can be described analytically through an asymptotic description as a slowly varying solitary wave direct numerical simulation of the variable coefficient extended korteweg de vries equation is performed for several oceanic shelves north west shelf of australia malin shelf edge and arctic shelf to demonstrate the applicability of the asymptotic theory it is shown that the solitary wave may maintain its sol

stable isotopes carbon 14 and hydrochemical composition from a basaltic aquifer in sao paulo state brazil the cretaceous serra geral aquifer sga is contained within one of the largest continental flood basalts in the world reaching a thickness up to 1700 m in the center of the parana basin the sga is one of the most important groundwater reservoirs in northeastern sao paulo state brazil responsible for water supply to cities and agriculture in order to evaluate the geochemical and isotopic evolution of sga as well as to determine the mean residence time a groundwater sampling campaign was carried out over the sga in sao paulo state brazil from january to april 2013 two main hydrochemical facies were recognized ca mg hco3 related to water rock interaction reactions in basaltic outcrop such as mineral dissolution due to atmospheric co2 uptake and alkaline na hco3 groundwater evolved from mixing with groundwater from the underlying guarani aquifer system stable isotope 18o and 2h ratios range from 8 87 to 5 32 vsmow and 61 31 to 31 64 vsmow respectively closely following the gmwl spatial and temporal variations in isotope ratios are associated with the south atlantic convergence zone activities and the type of rain responsible for recharge values for 13c vary from 21 53 to 7 11 vpdb while 14c activities vary from 1 2 pcm to more than 100 pcm presenting a trend to enrichment and decrease in 14c activities westward concordant with the regional groundwater flow direction most recent groundwaters have 13c ratio contents mostly consistent with c3 plants

geochemistry of the dubois greenstone succession an early proterozoic bimodal volcanic association in west central colorado abstract the dubois greenstone succession an early proterozoic supracrustal succession in west central colorado is composed of fine grained felsic volcaniclastic sediments ash flow tuffs and tholeiitic flows sills and dikes the volcanic rocks comprise a bimodal suite of tholeiite and rhyolite the tholeiites are divided into two groups group i exhibiting nearly flat ree patterns 20 30 chondrites and group ii with light ree enriched patterns 40 70 chondrites these groups can be produced by two stage melting of an undepleted or enriched garnet lherzolite source in which garnet remains in the residue of only the first melting stage which produces group ii magmas the felsic magmas can be produced by partial melting of a high grade gneiss in the lower crust in which zircon is entrained in the magma the dubois greenstone succession appears to have formed by felsic and mafic subaqueous eruptions in which some ash flows upon entering water underwent phreatomagmatic explosions giving rise to detritus which formed the volcaniclastic sediments although tectonic setting cannot be assigned to the succession with a high degree of confidence an immature back arc basin developed on sialic crust in consistent with most data

hydrochemical characteristics of aquifers near sutherland in the western karoo south africa the western karoo depends entirely on groundwater for domestic and agricultural use an understanding of the chemical evolution of the groundwater provides insight into the interaction of water with the environment and contributes to better resource management descriptive statistics correlation matrices and factor analysis together with stable isotope data were used to gain an understanding of the hydrochemical processes of the groundwaters in the fractured rocks around sutherland in the western karoo the main processes influencing the groundwater chemistry are salinisation mineral precipitation and dissolution cation exchange and human activity the stable isotope data indicate that the infiltration of evaporated water is partly responsible for the occurrence of saline subsurface waters the ionic oxygen and hydrogen stable isotope composition of the groundwaters suggests that the effects of localised topography are one of the overriding factors controlling the groundwater chemistry in higher lying areas ca hco3 2 type waters are prevalent while in topographical flat areas nacl type waters dominate in areas where water collects close to or at the surface saline soils are formed from these areas salts are leached to the subsurface during significant recharge periods these findings are important in that they contribute to the identification of suitable locations for developing groundwater resources that could yield a relatively better quality water q 2001 elsevier science b v all rights reserved

structure and generation of turbulence at interfaces strained by internal solitary waves propagating shoreward over the continental shelf abstract detailed observations of the structure within internal solitary waves propagating shoreward over oregon s continental shelf reveal the evolving nature of interfaces as they become unstable and break creating turbulent flow a persistent feature is high acoustic backscatter beginning in the vicinity of the wave trough and continuing through its trailing edge and wake this is demonstrated to be due to enhanced density microstructure increased small scale strain ahead of the wave trough compresses select density interfaces thereby locally increasing stratification this is followed by a sequence of overturning high density microstructure and turbulence at the interface which is coincident with the high acoustic backscatter the richardson number estimated from observations is larger than 1 4 indicating that the interface is stable however density profiles reveal these preturbulent interfaces to be o 10 cm thick much thinner than can be resolved with shipboard velocity measurements by as

role of an impermeable layer in controlling groundwater chemistry in a basaltic aquifer beneath an agricultural field jeju island south korea abstract hydrochemical data major cations and anions and trace metals such as fe mn and v of groundwater n 144 were collected from 15 pre existing wells in the gosan area along the southwestern coast of jeju island south korea between january and october 2010 these were used to investigate the spatio temporal variability of groundwater quality in a basaltic aquifer beneath an agricultural field in the western part of the study area an impermeable clay rich layer gosan formation overlies the basaltic aquifer prohibiting direct recharge from rainwater infiltration and allowing a shallow perched aquifer to form above the formation robust principal component analysis robpca was performed to investigate the hydrochemical characteristics twenty seven outlying samples were separated from the total dataset among these 17 samples reflected seawater effects and seven samples reflected abnormally high impacts from agricultural contamination for the rest regular observations n 117 and a good leverage point robpca showed that principal component pc 1 effectively distinguishes uncontaminated water from those samples reflecting agricultural contamination variables with positive pc 1 loadings tds ca mg no 3 so 4 and cl indicate agricultural contamination while negative pc 1 loadings ph na k hco 3 and v possibly indicate basalt weathering samples with chemistry controlled by agricultural contamination are restricted to the eastern part of the study area while uncontaminated water is predominantly observed in the western part where the gosan formation occurs such a distinct spatial pattern indicates that overall groundwater quality is regulated by the occurrence of the impermeable formation groundwater samples from wells near the edge of the gosan formation show seasonal fluctuations in water quality with factor scores that indicates uncontaminated water in the dry season january to april and agricultural contamination in the wet season may to october this suggests that groundwater below the marginal part of the impermeable layer is seasonally contaminated by a temporal extension of the pollution front during the wet season even though the impermeable layer plays a role as a natural barrier to protect groundwater from the infiltration of surface contaminants this study also shows the advantage of robpca to successfully identify spatio temporal variation of groundwater quality in an area where diverse hydrochemical processes are coexisting and anormalous samples occur

hydrogeochemical analysis of multiple aquifers in a coal mine based on nonlinear pca and gis hydrogeochemical characteristic analysis of multiple categorical aquifers including the delineation of hydrogeochemical spatial distributions can provide a basic understanding of the groundwater flow system necessary for the prevention and control of groundwater damage associated with coal mines nonlinear principal component analysis pca was used to analyse the groundwater chemical characteristics of water samples from five aquifers in gubei coal mine anhui province china in particular ca2 mg2 na k hco3 cl so4 2 and ph were analysed to analyse the spatial distribution of groundwater chemistry in this permian fractured aquifer interpolation of principal component 1 pc1 scores obtained from the nonlinear pca was performed using the inverse distance weighting idw method additionally concentrations of the hydrogeochemical variables were plotted against depth the relationships between water samples variables and water samples with variables were simultaneously analysed by nonlinear pca the results show 1 nonlinear pca explains more variability than standard pca in the first two principal components pcs 2 the cenozoic top aquifer has low concentrations of na k and cl the cenozoic middle aquifer and cenozoic bottom aquifer are characterised by high concentrations of ca2 and mg2 and low concentrations of hco3 the shallow groundwater of the permian fractured aquifer is recharged by the cenozoic bottom aquifer while other parts have high concentrations of hco3 and low concentrations of ca2 and mg2 the taiyuan limestone aquifer has similar groundwater chemistry to that of the cenozoic bottom aquifer and thus it may be recharged by the cenozoic bottom aquifer in outcropping taiyuan formation strata 3 the wide south western and north western areas of the permian fractured aquifer may be recharged by the cenozoic bottom aquifer and 4 concentrations of ca2 and mg2 in the permian fractured aquifer are negatively correlated with sampling depth while the concentrations of na k and hco3 are positively correlated with sampling depth which verifies that the shallow groundwater of this permian fractured aquifer is recharged by the cenozoic bottom aquifer the findings demonstrate that combining nonlinear pca with gis can be a powerful approach for conducting spatial nonlinear analysis of hydrogeochemical characteristics

formation of recirculating cores in convectively breaking internal solitary waves of depression shoaling over gentle slopes in the south china sea abstractthe formation of a recirculating subsurface core in an internal solitary wave isw of depression shoaling over realistic bathymetry is explored through fully nonlinear and nonhydrostatic

the degeneration of internal waves in lakes with sloping topography in a laboratory study we quantified the temporal energy flux associated with the degeneration of basin scale internal waves in closed basins the system is two layer stratified and subjected to a single forcing event creating available potential energy at time zero a downscale energy transfer was observed from the wind forced basin scale motions to the turbulent motions where energy was lost due to high frequency internal wave breaking along sloping topography under moderate forcing conditions steepening of nonlinear basin scale wave components was found to produce a high frequency solitary wave packet that contained as much as 20 of the available potential energy introduced by the initial condition the characteristic lengthscale of a particular solitary wave was less than the characteristic slope length leading to wave breaking along the sloping boundary the ratio of the steepening timescale required for the evolution of the solitary waves to the travel time until the waves shoaled controlled their development and degeneration within the domain the energy loss along the slope the mixing efficiency and the breaker type were modeled using appropriate forms of an internal iribarren number defined as the ratio of the boundary slope to the wave slope amplitude wavelength this parameter allows generalization to the oceanographic context analysis of field data shows the portion of the internal wave spectrum for lakes between motions at the basin and buoyancy scales to be composed of progressive waves both weakly nonlinear waves sinusoidal profile with frequencies near 10 24 hz and strongly nonlinear waves hyperbolic secant squared profile with frequencies near 10 23 hz the results suggest that a periodically forced system may sustain a quasi steady flux of 20 of the potential energy introduced by the surface wind stress to the benthic boundary layer at the depth of the pycnocline

instabilities in nonlinear internal waves on the washington continental shelf previous studies have identified two primary mechanisms shear instability and convective instability by which nonlinear internal waves nliws induce mixing on continental shelves to determine the relative importance of these and their dependence on background flow conditions we examine a much longer 6 month data set from a moored adcp thermistor chain with 2 m vertical spacing in which over 600 nliws are detected turbulent properties of the 318 waves with detectable overturning instabilities are documented using thorpe scales the 130 waves detected while an adcp was functioning are classified based on a froude number criterion fr uc where u is velocity in the wave propagation direction c is the wave phase speed of these 108 waves are identified as shear instability type i fr 1 composites are constructed by averaging in a wave coordinate frame over all waves in each category showing the mean spatial structure of dissipation and other wave quantities turbulence is highest at the sheared interface for type i waves and throughout the wave core for type ii waves no relationship between wave instability mechanisms and wave background parameters such as wave steepness stratification or mean flow is found except that unstable waves tend to be more energetic demonstrating a need to better understand wave propagation and breaking in complex and variable coastal oceanographic background flows

petrogenesis of the natkusiak continental basalts victoria island northwest territories canada the natkusiak flows 1100 m thick sills and dykes of victoria island northwest territories are part of an extensive late hadrynian magmatic event in the northern canadian shield the flows are subaerially erupted plateau basalts and together with associated doleritic sills and dykes display many geochemical features typical of continental tholeiites in addition to fractional crystallization the rocks were affected by crustal contamination but to a smaller degree than usually encountered in continental tholeiites elsewhere the basalts were derived from a depleted upper mantle source very similar to that of n type mid ocean ridge basalts although it is suggested that the melting residue contained small amounts of garnet 2

early proterozoic tectonics and metallogeny of the lake huron region of the canadian shield abstract deposition of the huronian supergroup dominantly fluvial clastic sediments with local basal volcanic accumulations began at 2 49 ga in a broad trough that extended far south of the present lake huron area atop a large archean continent that was assembled at 2 7 ga and broken up at 2 15 ga after intrusion of widespread gabbro sheets and dykes including nipissing diabase the wyoming province which contains sequences similar in age and stratigraphy to the distinctive huronian supergroup may be a fragment of this continent the superior province is a much larger fragment tectonic controls of deposition of the huronian and its paleoplacer uranium deposits and of the pre 2 2 ga deformation of these strata were probably unrelated to processes that controlled deposition of the animikie and marquette range sequences in the lake superior region at 2 0 ga the huronian animikie and marquette range sequences were deformed during the 1 85 ga penokean orogeny which occurred when an assembly of island arc terranes collided with the superior block the sudbury structure including the whitewater group and its contained sedex deposits and the sudbury igneous complex and its ni cu pge ores were also formed at 1 85 ga the elliot lake pyritic paleoplacer uranium ores myriad lenses of radioactive pyritic gravels were deposited by early huronian fluvial systems other endogenic huronian mineral deposits include disseminated ni cu sulphides in gabbros cu in red beds high in the huronian succession and silica in quartz arenites intrusions of nipissing gabbro near sudbury contain minor ni cu mineralization these intrusions also caused recycling of metals from archean and huronian rocks to form concentrations of cu au ag fe and w in veins and other epigenetic deposits most important of these are the unconformity related ag veins of the cobalt area which had particularly complex still undeciphered histories that probably included pre huronian weathering metallogenic patterns in the early proterozoic rocks were controlled by a complex interplay of factors including the distribution of mineral deposits in the archean basement tectonically controlled variations in huronian deposition and deformation and oxyatmoversion the transition from anoxic to oxygenic atmospheric conditions that occurred during deposition of the huronian supergroup

regional cross section of the southern province adjacent to lake huron ontario implications for the tectonic significance of the murray fault zone the southern province in the lake huron area of ontario and the penokean fold belt of minnesota wisconsin and michigan have the earmarks of a collisional orogen the huronian supergroup a southerly facing passive margin sequence was deposited during early aphebian early proterozoic crustal stretching and ocean basin formation along the southern margin of the superior province archean craton it accumulated as four unconformity bounded northerly tapering onlapping clastic wedges megacycles the thickness and facies variations reflect syndepositional down to the basin south normal faulting that controlled the accumulation and preservation of the lower three huronian megacycles these are overlapped northward by the youngest megacycle an extensive sheet of clastic sediments recording post stretching regional subsidence of the cratonic margin due to cooling and thermal contraction soft sediment folds in the rocks of the youngest megaycycle to the extreme south probably indicate southward slu

multivariate statistical analysis for identifying water quality and hydrogeochemical evolution of shallow groundwater in quaternary deposits in the lower kelantan river basin malaysian peninsula a long term hydrogeochemical data set is used in this study to evaluate the water quality and hydrogeochemical evolution of shallow groundwater in a quaternary deposit a multivariate statistical method hierarchical cluster analysis hca is applied to overcome the problem of a large number of data points in the integration interpretation and representation of the results hca is applied to a subgroup of the hydrogeochemical data set to evaluate their usefulness to classify the groundwater bodies this subgroup consists of 27 groundwater wells and 15 variables ph total dissolved solids electrical conductivity ec na ca2 mg2 k hco3 cl so42 fe mn nh4 no3 and sio2 only 12 chemical variables were used for the analysis four clusters have been identified c1 c4 with two main prevalent facies na hco3 and ca hco3 the hydrogeochemical evolution of shallow groundwater is governed by the processes of precipitation weathering dissolution and ion exchange

age petrogenesis and tectonic setting of the thessalon volcanic rocks huronian supergroup canada abstract the 2 5 ga huronian supergroup volcanic rocks in northern ontario represent one of the better preserved paleoproterozoic continental flood basalt sequences on earth the youngest age of huronian supergroup volcanism is refined to 2452 5 6 2 ma based on new u pb zircon analyses of the copper cliff rhyolite recent mapping and geochemical analyses of thessalon formation volcanic rocks define a well developed chemostratigraphy a lower series consisting of four geochemically distinct mafic lava sequences and an upper basalt andesite volcanic series these two mafic volcanic series are separated by felsic volcanic rocks rhyolite and dacite the mafic lavas are low ti tholeiites dominated by basalt and andesite and are characterized by enriched light rare earth element profiles and high th contents up to 12 ppm most basalt andesite sequences show some internal geochemical variation reflecting a combination of fractional crystallization and in some cases limited crustal contamination but each sequence represents a discrete magma batch derived by different degrees of partial melting in the subcontinental lithospheric mantle all magma batches display prominent negative nb ta and ti anomalies on primitive mantle normalized multi element diagrams interpreted to reflect melting of a heterogeneous and previously metasomatized garnet lherzolite that acquired some chemical characteristics of a source typical of subduction zone magmatism at least three distinct mantle source compositions are required to explain the range in the observed lava compositions the most unusual of these reservoirs has a number of geochemical features akin to upper continental crust and is characterized by high th yb 10 and low zr nb 11 this reservoir is interpreted to be peridotite modified through metasomatism and entrapment of arc magmas during northward neoarchean subduction along the southern superior craton margin

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