compositional gradients surrounding spherulites in obsidian and their relationship to spherulite growth and lava cooling spherical masses of crystal fibers spherulites crystalize from rhyolitic melt glass mainly in response to significant undercooling while lava cools spherulite growth should induce compositional gradients in the surrounding glass from expulsion of incompatible constituents and diffusion of those constituents away from the spherulite finite difference numerical modeling of one dimensional diffusion in which diffusivities are allowed to vary with temperature is used to investigate how compositional gradients reflect spherulite growth and lava cooling overall three forms of gradients are identified elements that diffuse quickly are expelled from the spherulite but then migrate away too quickly to become enriched at the boundary of the spherulite elements that diffuse slowly are trapped within the growing spherulite between those endmembers are elements that are not trapped yet diffuse slow enough that they become enriched at the contact their slow diffusion away then elevates their concentrations in the surrounding glass how enriched those elements are at the spherulite matrix interface and how far their enrichments extend outwards into the glass reflect how spherulites grow and thermal conditions during growth concentrations of h2o rb f li cl na k sr cs ba and be were measured in and around spherulites in obsidian from a 4 7 1 km3 rhyolite lava dome erupted from tequila volcano mexico measurable concentration gradients are found for h2o rb and f attributes of those gradients and the behaviors of the other elements are in accord with their experimentally constrained diffusivities spherulites appear to have grown following radial rather than volumetric growth the observed gradients and lack of others are more consistent with growth mainly below the glass transition which would necessitate the dome cooling at ca 10 5 to 10 7 c s 1 such slow cooling is consistent with the relatively large volume of the dome

on the skaergaard intrusion and forward modeling of its liquid line of descent a reply to principles of applied experimental igneous petrology by morse 2008 lithos 105 pp 395 399 abstract forward modeling based on an experimental investigation successfully duplicated main features of the gabbros in the skaergaard layered series thy p lesher c e nielsen t f d and brooks c k 2006 experimental constraints on the skaergaard liquid line of descent lithos 92 154 180 the foundation for the modeling was equilibrium melting experiments that were controlled by temperature and oxygen fugacity at low pressure conditions the experimental techniques and methods were chosen to represent a reasonable approximation to the inferred emplacement and crystallization conditions of the skaergaard intrusion the dike rocks used as starting materials define a strong differentiation trend that represents the skaergaard liquid line of descent this suite of dikes allowed liquidus conditions to be defined for a range of composition and temperature the initial redox conditions were chosen based on measured and calculated estimates for the gabbros of interest the melting experiments defined liquidus and subliquidus conditions that were used to understand crystallization of the lower and middle zones of the skaergaard layered series and can be extrapolated to the upper zone gabbros assuming perfect fractional crystallization the forward modeling reproduces the cryptic variation seen in the main gabbro minerals olivine augite plagioclase well into the upper zone and provides reasonable liquidus temperatures and compositions it can be shown that based on the assumption of fe ti oxide modes in the middle and upper zones a range of oxygen fugacity trends can be obtained we repeat our previous conclusion that iron depletion and strong reduction in oxygen fugacity in the upper zone are only feasible for very high fe ti oxide modes that exceed the experimental evidence as well as the observations from the gabbros a strong drop in oxygen fugacity in the upper zone requires a significant sink for fe ti oxides that so far has not been identified we thus reject morse s morse s a 2008 principles of applied experimental igneous petrology a comment on experimental constraints on the skaergaard liquid line of descent by thy lesher nielsen and brooks 2006 lithos 92 154 180 lithos 105 pp 395 399 contention that we violated in our original study established principles of applied experimental igneous petrology such principles dictate that experimental and forward models are carefully tested against field observations before petrologic processes can be verified

diffusion of ca and f in haplogranitic melt from dissolving fluorite crystals at 900 1000 c and 100 mpa 1 the diffusion rates of ca and f into haplogranitic melt were determined by concentration profiles in glasses produced by dissolving fluorite crystals into haplogranitic melt at 900 1000 c and 75 100 mpa starting products were synthesized from oxides of haplogranitic composition at two aluminosities na2o k2o al2o3 1 05 and 1 68 fluorite crystals or crystal powders were coupled with powders or solid cylinders of haplogranitic glass water was added to the runs resulting in two runs at h2o 1 20 and 1 40 wt and three runs thought to be water saturated the materials were then subjected to the conditions of interest in either a stellite cold seal apparatus or an internally heated pressure vessel electron microprobe traverses of the quenched glasses produced in these experiments revealed negative concentration gradients in ca and f away from the fluorite glass boundary these gradients are comparable to an error function solution in the first approximation for specific ca and f diffusivities dca and df respectively the ca diffusion coefficient increased from 3 36 0 19 10 9 to 2 16 0 28 10 8 cm2 s and f diffusivity increased from 1 16 0 09 10 8 to 6 59 0 62 10 8 cm2 s as temperature increased from 900 to 1000 c these diffusivities are comparable to other published melt diffusion data for the dissolution of multicomponent minerals where the diffusants move independently calcium and fluorine diffusivities increase from 2 77 0 09 10 9 to 2 16 0 28 10 8 cm2 s and from 2 27 0 10 10 8 to 6 59 0 62 10 8 cm2 s respectively with increasing water content at 1000 c likely due to melt depolimerization the large difference in the concentrations of ca c0ca and f c0f at the fluorite glass interface suggests that these two elements diffuse independently in the melt in contrast the concentration gradient for na parallels that of f suggesting complexing between these two elements

diffusion of dissolved co2 and cl in hydrous silicic to intermediate magmas the bulk diffusivity of dissolved co sub 2 in obsidian and dacite melts containing 0 11 wt dissolved water at 800 1 100c and 1 gpa was characterized using a sup 14 c radiotracer technique five values were also obtained for cl in melts containing 8 h sub 2 o carbon dioxide diffusivity d sub co sub 2 in nominally dry molten obsidian is similar to previously reported values for a simple melt in the na sub 2 o al sub 2 o sub 3 sio sub 2 system and for dry basalt indicating little effect of melt composition on bulk co sub 2 diffusion three d sub co sub 2 values for hydrous dacite melt are consistent with this lack of a melt composition effect dissolved water however causes an increase of d sub co sub 2 in molten obsidian by about an order of magnitude for each 5 of added water the activation energy of approximately 18 kcal mol is lower by a factor of approximately 3 than that for diffusion in dry basalt in comparison with existing data for diffusion of water in silicic melts at their typical liquidus temperatures d sub co sub 2 is generally lower unless the melt contains more than about 6 dissolved h sub 2 o in which case d sub co sub 2 approximately d sub h sub 2 0 the few data obtained frommore chlorine diffusion reveal the d sub cl is lower by a factor of 5 10 than d sub co sub 2 in the same melt the overall systematics of the new data on dissolved volatile diffusion indicate that diffusional fractionation effects are likely to be most significant in silicic to intermediate magmas having water contents in the 0 4 range less

the skaergaard liquid line of descent revisited there is a fundamental conflict between the suggestion that the iron content of skaergaard liquids increases during fe ti oxide fractionation and the observation that at the same time oxygen fugacity f text o text 2 drops by two log units below the fayalite magnetite quartz oxygen buffer fmq a new petrographic study of average skaergaard gabbros shows that the total modal content of fe ti oxides is about 22 in the early lzc and markedly decreases to below 5 in the uzc forward modeling based on these modal constraints as well as experimental results on skaergaard related dikes predicts that fractionation of troctolitic lza gabbros drives the derivative liquid towards a high iron content strong iron enrichment continues together with a small decline in silica during lzb crystallization due to the appearance of augite as a fractionating phase the fractionation of fe ti oxides in the lzc initially suppresses iron enrichment and reverses the silica trend to one of slight enrichment however continued evolution into the uz produces liquids with maximum uzc feo content of 23 25 wt and sio2 content of 53 wt feo is total iron as feo the maximum in feo is dependent on several factors of which the fe ti oxide mode has the strongest effect the f text o text 2 during crystallization of the lzc is widely thought to have been at or slightly below the fayalite magnetite quartz oxygen buffer fmq under closed system evolution incorporation of ferric iron into augite during formation of the lzb restricts the increase in f text o text 2 to about 0 1 log units above fmq 0 1 fmq likewise crystallization of the lzc through the uza involving fe ti oxide minerals leads to a decline in f text o text 2 of less than 0 1 fmq crystallization of the uzb c gabbros results in oxidation to a maximum of 0 5 fmq this behavior can account for the iron rich character of the uz gabbros as well as the low modal content of fe ti oxides thus evolved skaergaard liquids are high in iron and contain a modest amount of sio2 our modeling result do not account for a strong drop in f text o text 2 through the layered series such a drop would require an unacceptably high proportion of fe ti oxides and high magnetite content in the fractionating assemblage

yield criteria for glaciotectonically deformed deposits abstract most glaciotectonically deformed deposits including varved clays and glacial tills are characterised by cracks and fissures this paper presents a method for describing the yield criteria for glacitectonically deformed cohesive deposits using a model of cracked geomaterial with isotropic or anisotropic matrix the general representation of the limit conditions for anisotropic materials in plane strain is used to determine the yield criterion the yield criterion represents a convex piece wise surface in the three dimensional stress space revealing explicitly global plastic properties of the materials considered an example of using proposed yield criteria to solve a bearing capacity problem of a strip foundation constructed on a glaciotectonically cracked layer is presented the lower and upper bound estimates of limit loads on the strip footing are given the limit state analysis presented in this paper can be used to solve many other geotechnical engineering problems for example the stability of slopes and reinforced walls or the bearing capacity of pile foundations

relationship between electrical resistivity and basic geotechnical parameters for marine clays recently considerable efforts have been made in the attempt to map quick clay areas using electrical resistivity measurements however there is a lack of understanding regarding which soil parameters control the measured resistivity values to address this issue inverted resistivity values from 15 marine clay sites in norway have been compared with basic geotechnical index properties it was found that the resistivity value is strongly controlled by the salt content of the pore fluid resistivity decreases rapidly with increasing salt content there is also a relatively clear trend of decreasing resistivity with increasing clay content and plasticity index resistivity values become very low 5 m for high clay content 50 medium to high plasticity ip 20 materials with salt content values greater than about 8 g l or corresponding remoulded shear strength values greater than 4 kpa for the range of values studied there is poor correlation between resistivity and bulk density and between r

a modified seismic reflection approach for engineering geology investigation in fractured rock zones abstract delineating soil rock interface is critical for geotechnical and tunnel site investigations in engineering geology in singapore we also need to draw attention to local faults and fractured rock zones because the regional geology of peninsular malaysia and singapore contains some minor steep and brittle faults propagating at some areas in the island city in addition to drilling boreholes seismic reflection survey is a viable option to mitigate the uncertainties in areas without boreholes however the current practice of seismic reflection still follows the methods used in the petroleum exploration community this investigation reviews and modifies the seismic reflection approach specifically customized for geotechnical and tunnel site investigation which is partly different from petroleum exploration we demonstrate the modified approach through a field testing in singapore the resultant image from the field test fairly captures the soil rock interface and it is validated based on the vertically drilled boreholes a local fault or a fracture rock zone is also identified in the migrated image the extent and location match with the record of horizontal directional coring hdc this addresses the concern of fracture rock zone raised from the regional and local geology and provides useful information for geotechnical and tunnel engineers in addition we further discuss the general challenges of using the modified seismic reflection approach this work aims to help the geotechnical and tunnel community better understand the non invasive seismic reflection survey

characterization of norwegian marine clays with combined shear wave velocity and piezocone cone penetration test cptu data a database of research quality piezocone cone penetration test cptu and shear wave velocity vs information for norwegian marine clays has been assembled to study the small strain stiffness relationships for these materials and to examine the potential use of cptu and vs data in combination for the purposes of characterizing these soils data for sites where high quality block sampling was carried out have mostly been used improvements have been suggested to existing correlations between the small strain shear modulus gmax or vs and index properties for these soils recent research has shown that cptu corrected cone tip resistance qt and especially the pore pressure measured during cptus u2 and vs can be measured reliably and repeatably and are not operator or equipment dependant therefore a new soil classification chart involving the normalized cone resistance qt and normalized shear wave velocity vs1 or vs1 and u v0 where u is the pore water pressure and v0 is the in situ vertical

interpretation of piezocone penetration and dissipation tests in sensitive leda clay at gloucester test site a modified piezocone penetration test cptu analytical solution based on spherical cavity expansion and critical state soil mechanics sce cssm is employed for assessing yield stress undrained s

characterisation and engineering properties of tiller clay abstract a detailed characterisation of the quick clay underlying the ntnu research site at tiller trondheim is presented the objective of the work is to provide guidance on quick clay parameters to engineers and researchers working with similar clays in scandinavia and north america especially on landslide hazard assessment the material is lightly overconsolidated and is characterised by its high degree of structure and very high sensitivity quick clay clay and water contents are both about 40 the plasticity index is low 5 this relates to the low active minerals of the clay and silt fractions illite chlorite and quartz feldspars respectively undrained shear strength is of the order of 30 kpa to 50 kpa medium stiff and increases with depth the deposit is consistent across the site and its properties are similar to other norwegian quick clays significant efforts have been made into examining sample disturbance effects on the material it was found that thin walled steel fixed piston samples can yield results similar to those of block samples provided the work is carried out with extreme care and storage time is minimised the piezocone cptu test proved very useful in characterising the material

integration of sh seismic reflection and love wave dispersion data for shear wave velocity determination over quick clays quick clay is a water saturated formation originally formed through flocculation and deposition in a marine to brackish environment it is subsequently leached to low salinity by freshwater flow if its strength decreases then the flocculated structure collapses leading to landslides of varying destructiveness leaching can result in a reduction of the undisturbed shear strength of these clays and suggestions exist that a reduction in shear wave velocities is also possible integration of sh seismic reflection and love wave dispersion data was undertaken in an area near the gota river in southwest sweden to evaluate the potential of shear wave velocity imaging for detecting quick clays seismic reflection processing evidenced several geologically interesting interfaces related to the probable presence of quick clays locally confirmed by boreholes and sand gravelly layers strongly contributing to water circulation within them dispersion data were extracted with a gaussian windowing approach and inverted with a laterally constrained inversion using a priori information from the seismic reflection imaging the inversion of dispersion curves has evidenced the presence of a low velocity layer lvl with a velocity reduction of ca 30 per cent probably associable to quick clays this velocity reduction is enough to produce detectable phase velocity differences in the field data and to achieve a better velocity resolution if compared to reflection seismic velocity analyses the proposed approach has the potential of a comprehensive determination of the shear wave velocity distribution in the shallow subsurface a sensitivity analysis of love wave dispersion data is also presented underlining that despite limited dispersion of the data set and the velocity reducing effect of quick clay leaching the proposed interpretation procedure arises as a valuable approach in quick clay and other lvl identification

the probable occurrence of interstitial al in hydrous f bearing and f free aluminosilicate melts experiments carried out on the system sio2 naalsi3o8 kalsi3o8 qz ab or at 1 kbar in the presence of h2o and f show that the quartz alkali feldspar field boundary is progressively displaced towards the feldspar join as f contents increase from 0 to 4 wt f increasing p h 2 o in the absence of f has already been shown to have a similar effect tuttle and bowen 1958 luth jahns and tuttle 1964 the increased size of the quartz field in the f bearing system compared to the hydrous system is believed to be caused by progressive removal of al from the tetrahedral network of the melt by complexing with f the residual network in the melt is thus enriched in si and this stabilizes precipitation of quartz rather than feldspar for certain bulk compositions the common presence of quench cryolite na3alf6 in certain experiments carried out with 4 wt f supports this interpretation and indicates that some al in the melt may be present in six fold coordination with f the effect of h2o in the absence of f may be similar with al being progressively removed from four fold coordination as more h2o is dissolved in the melt although a proportion of al in hydrous melts may occur in six fold coordination dry melts predominantly contain al in four fold coordination this major difference in al complexing may be one of the main causes for differences in the high pressure phase relations of wet and dry albearing silicate systems

review of long seabed samplers and criteria for new sampler design a cost efficient way of investigating shallow sediments and for collecting soils data for many offshore geotechnical problems e g anchoring of floating structures with suction piles or evaluation of submarine slope stability is to carry out seabed sampling to say 25 m below seabed and in addition perform seabed cptus to say 40 m based on a review of data collated from the literature and from in house project experience at the norwegian geotechnical institute it was found that kullenberg type piston core samples give poor recovery and samples which are increasingly disturbed as penetration increase this means that laboratory tests on these samples will give results that are not representative of in situ conditions and will give incorrect parameters for foundation design many different factors control the quality of the samples recovered but the need for an effectively stationary piston a core retainer and improvements to the physical sampler parameters e g diameter wall thickness ratio cutting edge angle inside and outside friction are perhaps the most critical the importance of each of these factors is discussed in detail in addition to the need for instrumentation and the way to penetrate the sampler recommendations are given in terms of criteria for the design of a new sampler which the authors feel will give better results than most samplers used in practice today

interpretation of in situ test results from the canlex sites one of the primary objectives of the canadian liquefaction experiment canlex project was to evaluate in situ testing techniques and existing interpretation methods as part of the overall goal to

quantitative estimation of clay mineralogy in fine grained soils stabilization design guidelines based on soil plasticity properties have certain limitations soils of similar plasticity properties can contain different dominant clay minerals and hence their engineering behavior can be different when stabilized with the same chemical additive and dosage it is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used chemical properties of a soil including cation exchange capacity cec specific surface area ssa and total potassium tp are dependent on clay mineral constituents and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses this approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy a total of twenty natural and six artificial soils were considered and used in the chemical analyses test results and subsequent analyses including the development of artificial neural network ann based models are evaluated and described in this paper

on the prediction of settlement from high resolution shear wave reflection seismic data the trondheim harbour case study mid norway abstract this paper presents a novel approach to predict long term settlement in the trondheim harbour mid norway from high resolution shear wave seismic reflection data complemented with cone penetration test results cptu and index soil properties from nearby boreholes in this reclaimed coastal area the data enables sub surface geo characterisation in high resolution down to the basement at a depth of about 175 m correlations between shear wave velocity and janbu s classical 1d consolidation parameters m m0 m1 c and ocr are used for settlement analysis both the magnitude and rate of time settlement predictions compare well with the measured settlements from gps levelling and psinsar data acquired since the late 1980s and the early 1990s in the area respectively the shear wave reflection data further provide important input to understand the spatial patterns of land subsidence in the trondheim harbour the highest settlement rates occur in areas where depth to bedrock is greatest and where thicker deposits with low stiffness are found in summary the data and workflow presented here are useful tools for predicting settlements based on correlations with shear wave velocity measurements

correlations between shear wave velocity and in situ penetration test results for korean soil deposits shear wave velocity v s can be obtained using seismic tests and is viewed as a fundamental geotechnical characteristic for seismic design and seismic performance evaluation in the field of earthquake engineering to apply conventional geotechnical site investigation techniques to geotechnical earthquake engineering standard penetration tests spt and piezocone penetration tests cptu were undertaken together with a variety of borehole seismic tests for a range of sites in korea statistical modeling of the in situ testing data identified correlations between v s and geotechnical in situ penetration data such as blow counts n value from spt and cptu data including tip resistance q t sleeve friction f s and pore pressure ratio b q despite the difference in strain levels between conventional geotechnical penetration tests and borehole seismic tests it is shown that the suggested correlations in this study is applicable to the preliminary determination of v s for soil deposits

multichannel analysis of surface waves masw for offshore geotechnical investigations abstract multichannel analysis of surface wave masw surveys are commonly used onshore to produce shear wave velocity vs profiles this paper describes its use in offshore geotechnical investigations underwater masw umasw where the focus was on the upper 15 m of the sediment profile to aid the design of structures such as marine pipelines cable routes and shallow anchor systems umasw was shown to provide reliable data in irish offshore conditions in water depths of up to 50 m the receiver spacing and array length rather than the characteristics of the air gun seismic energy source were the primary control on signal penetration and resolution of individual sediment layers good resolution of the properties of the upper 5 m of sediment was found by reducing the receiver spacing to as low as 0 3 m a test site with a broad intertidal zone allowed coincident land marine and direct measurements to be compared and vs profiles obtained from umasw onshore masw and by seismic cone testing scptu were in good agreement vs profiles estimated from published correlations with cptu data in sandy sediments agreed well with the measured values inversion of data using different software packages showed only a minor variation in results

mechanical behavior of silty soils of the venice lagoon as a function of their grading characteristics the main feature of the shallowest quaternary basin of the well renowned historic city of venice italy and its surrounding lagoon is the presence apparently without any regular trend in depth and site of a predominant silt fraction this is always combined with clay and or sand forming a chaotic and erratic interbedding of different sediments whose mineralogy is however variable in a relatively narrow range due to a unique geological origin and a common depositional environment after a brief description of the basic soil indexes of the venice lagoon soil the present study based on a comprehensive geotechnical laboratory investigation describes the range of variation of the most relevant time independent geotechnical properties moreover a new grain size index combining the geometrical characteristics of the particle distribution is introduced it is shown that the soil response at large and very small strains can be related to this grain size index which appears to be able to include the in

experimental constraints on the mobility of rhenium in silicate liquids abstract the volatization of rhenium re from melts of natural basalt dacite and a synthetic composition in the cao mgo al2o3 sio2 system has been investigated at 0 1 mpa and 1250 1350 c over a range of fo2 conditions from log fo2 10 to 0 68 experiments were conducted using open top pt crucibles doped with re and yb analysis of quenched glasses by laser ablation inductively coupled plasma mass spectrometry la icp ms normal to the melt gas interface showed concentration profiles for re to which a semi infinite one dimensional diffusion model could be applied to extract diffusion coefficients d the results show re diffusivity in basalt at 1300 c in air is log dre 7 2 0 3 cm2 s and increases to log dre 6 6 0 3 cm2 s when trace amounts of cl were added to the starting material at fo2 conditions below the nickel nickel oxide nno buffer re diffusivity decreases to log d re reducing 7 6 0 2 cm 2 s and to log d re dacite 8 4 0 2 cm 2 s in dacitic melt in the cmas composition log d re cmas 7 5 0 1 the diffusivity of re is comparable to ar and co2 in basalt at 500 mpa favoring its release as a volatile our results support the contention that subaerial degassing is the cause of lower re concentrations in arc type and ocean island basalts compared to mid ocean ridge basalts

an experimental study of the influence of oxygen fugacity on fe ti oxide stability phase relations and mineral melt equilibria in ferro basaltic systems

continuous interval shear wave velocity profiling by auto source and seismic piezocone tests a new exploratory procedure for collecting continuous shear wave velocity measurements via cone penetration testing using a special autoseis source is presented whereby wavelets can be generated and recorded every 1 to 10 s the continuous interval seismic piezocone test ciscptu offers a fast productive and reliable means to expedite the collection of downhole shear wave velocity profiles as well as additional readings on cone tip resistance sleeve friction and penetration porewater pressures with depth a site in windsor virginia is utilized for illustrating the collection of data calibration and post processing issues arising from large numbers of wavelets that require filtering windowing and selection in both time and frequency domain analyses at the test site the geology consists of shallow holocene deposits of clays and sands to 8 m that are underlain by much stiffer calcareous sandy marine clay soils of miocene age which extend beyond the termination depths of the soundings at 30 m

ion microprobe studies of water in silicate melts concentration dependent water diffusion in obsidian abstract the temperature dependence of water diffusivity in rhyolite melts over the range 650 950 c and pt h2o 700 bars is evaluated from water concentration distance profiles measured in glass with an ion microprobe diffusivities are exponentially dependent on concentration over this temperature range and vary from about 10 8 cm2 s at 650 c to about 10 7 cm2 s at 950 c at 2 wt water water solubility also varies with temperature at a rate of 0 14 wt per 100 c increase the avtivation energy ea appears to be constant at 19 1kal mole for 1 2 and 3 wt h2o comparison of these data with results for cation diffusion indicates that this value is a minimum ea for diffusion of any species in a rhyolite melt compensation plots of log10d0 the frequency factor versus ea indicate that hydrous rhyolite melts follow the same trend as anhydrous basalts d0 increases for h2o and ca2 1 as ea decreases this suggests that these molecules may diffuse by different mechanisms than do monovalent cations and that hydration of the melt affects diffusion of ca2 and h2o differently than it does monovalent cation diffusion the results imply that dramatic increases in cation diffusivities by hydration 1 may occur with additions of less than 1 wt h2o

experimental equilibrium tested by plagioclase loop widths are solid and liquid respectively and an is the mole fraction or per cent an an ab it is measured from the plagioclase composition and an estimate of the liquid composition based on standard assumptions rooted in the norm recalculation routine a survey of a large new database allows study of the 1 atm experimental literature involving 819 experiments the approach to equilibrium is tested empirically by the loop width and its transform the linear partitioning function kd this function is the exchange coefficient formed as the intercept at pure an s from the array over all x s of the partition coefficient d when defined as x s x l w herex is the mole fraction d and kd are thus limited to lie between zero and 1 0 the results show a 1atm loop width ranging from 0 2t o 68 mol a n with associated kd 0 03 0 98 these extrema represent loops both far too small and far too large to represent stable equilibrium between plagioclase and liquid some of the higher values lie near the persodic limit because the an component of the liquid is scarce and the liquid composition is ab rich the loops from ne normative liquids span the range from 40 to 90 mol an in the crystal with loops 2 50 mol wide a baseline for loop width is derived from the precise synthetic study of the system di an ab at 1atm and an array of high pressure data that extrapolates to the same value of kd 0 26 at 1atm many of the 1atm experimental data fall far outside any reasonable uncertainty limits on the baseline causes of departure include crystal disequilibrium that can lead to errors in both directions and compositional problems comparison of the values of kd with liquid compositions in silica oxygen fugacity temperature kinetics and sodium reveals the common presence of sodium deficiency a crystallinity study shows a definite decrease in sodium content with liquid evolution whereas the sodium content should increase or at least remain nearly constant with evolution of the melt a selection of self consistent 1atm data from a few laboratories shows a close correspondence to the standard distribution of loop widths and indeed most literature data lie within the limited range of kd 0 26 0 4 experiments known to be hydrous show very low values of kd and corresponding large loop widths as previously understood from literature data when data limited to nearbaseline kd values are plotted against temperature they yield expected thermal slopes and concave up curves of temperature plotted against plagioclase composition literature data show a positive correlation of kd with dry pressure and a separate database from 2 to 15 kbar shows that more than half the data comport with this pressure effect a different group ranges down to kd as low as 0 2 with increasing loop widths some of these are alkalic and hence rich in the ab component of the liquid others were obtained in fe containers that control the oxygen fugacity to low values and convert the fayalite component of the liquid to iron oxygen and silica this reaction increases the activity of silica and in turn the activity of ab in the melt thus widening the loop thermodynamic studies concerned with plagioclase melt equilibria will profit from an awareness of these effects

a release to rest model for dynamically installed anchors abstractdynamically installed anchors are torpedo shaped anchors that are installed by dropping them through the ocean such that they self bury in the soft seabeds typically encountered in deep wat

toward a thermal model for the skaergaard liquidus after a review of history it is shown that in a comprehensive 1 atm study by mcbirney and naslund 1990 the skaergaard liquidus temperature is linear from lza to uza on stratigraphic height when corrected to pressure the augite saturation point at lza b has the same liquid composition in terms of plagioclase an content as the corresponding point in the kiglapait intrusion studied at 5 kbar by morse et al 2004 this temperature 1203 c at 5 kbar is transformed to the skaergaard pressure at lza b to a value of 1173 c from this fixed point all other liquidus temperatures at skaergaard are scaled to mean plagioclase core compositions from a detailed study by toplis et al 2007 all such points from lzb to uza lie within experimental error on the regression from mcbirney and naslund and the further points in uzb and uzc also agree plagioclase based temperatures at the base of lza exceed the earlier estimates by 24 c and imply a possible temperature of 1210 c in the hidden zone these results provide a good interim model for the skaergaard liquidus pending further experimental study at the liquidus

on the use of the norwegian geotechnical institute s prototype seabed coupled shear wave vibrator for shallow soil characterization i acquisition and processing of multimodal surface waves summary pure shear wave data are only very rarely acquired for offshore site investigations and exploration here we present details of a novel seabed coupled shear wave vibrator and field data recorded by a densely populated multicomponent ocean bottom cable to improve shallow soil characterization the prototype shear wave vibrator uses vibroseis technology adopted for marine environments through its instalment on top of a suction anchor assuring seabed coupling in combination with self weight penetration the prototype is depth rated to 1500 m water depth and can be rotated while installed in the seabed the philosophy is to acquire fully complementary seismic data to conventional p and p to s converted waves in particular for 2 d profiling vsp vertical seismic profiling or monitoring purposes thereby exploiting advantages of shear waves over compressional waves for determining for example anisotropy small strain shear modulus and excess pore pressures effective stress the source was primarily designed for reservoir depths however significant energy is emitted as surface waves which provide detailedgeotechnicalinformationthroughmappingofshearwavevelocitiesinpotentiallyhigh resolution of the upper soil units to fully utilize pure shear wave content a proper analysis of surface waves is paramount due to the proximity of surface wave propagation speed with shear wave velocities the experiment was carried out in the northern north sea in 364 m water depth cable dragging was necessary to obtain close receiver spacing 2 5 m effective spacing with total line length of 600 m frequency waveform transforms reveal both scholte and love waves up to six surface wave modes are identified that is fundamental mode and several higher surface wave modes the occurrence of these two different dispersive surface wave types with well resolved higher modes allows for a unique analysis and inversion scheme for highresolution mapping of physical properties in the shallow subsurface as well as anisotropy which is discussed in an accompanying paper the data presented in this paper are thus a unique long and densely populated receiver array allows for multimodal love and scholte surface waves from the marine environment but challenging marine operations marine data set

liquidus temperatures of the skaergaard magma the liquidus temperatures of the skaergaard intrusion can be estimated for the layered series from plagioclase compositions plagioclase saturation in one atmosphere melting experiments on evolved north atlantic basalts is a function of an content mol and can be described by an empirical linear relationship t c 899 3 6 an 1 20 c this relationship predicts a total crystallization interval for the intrusion of 150 c plagioclase crystallized in the hidden zone an 71 at 1155 c at the base of the lower zone an 66 at 1137 c and finally in the sandwich horizon an 30 at 1007 c these temperatures are in good agreement with previous estimates based on melting studies of suitable chilled margin rocks and gabbros from the skaergaard intrusion and liquid line of descent modeling our temperature estimates however are markedly lower by up to 60 c than recent temperature estimates based on an extrapolation of high pressure experimental data for the kiglapait intrusion to skaergaard emplacement conditions proposed variations in magmatic pressure during skaergaard evolution and reasonable estimates of magmatic water contents do not alter these conclusions

measuring shear wave velocity vs of a hidden layer an application to soil improvement under roads in a number of practical cases a typical one being the investigation of the subsoil properties below roads or foundations one faces the problem of measuring the elastic properties of a geological layer here called hidden layer underlying a more compact and rigid surface layer in such cases the effectiveness of common surface seismic methods is poor for different reasons but mostly linked to the reflection transmission properties of the waves at a stiff to soft interface borehole methods are more efficient but expensive and only provide vertical information at certain points attempts carried out in the past to characterize the hidden layer properties through surface seismic techniques consisted in placing the seismic source on the surface alongside but off the stiff artificial layer road or foundation an alternative approach is presented based on placing the seismic source just below the stiff artificial layer in cases where soil improvement compaction are carried out through injection of

analysis and interpretation of piezocone data on the silty soils of the venetian lagoon treporti test site this paper reports the main results of an extensive piezocone testing campaign performed over the last years at the treporti test site venice italy within a long lasting and comprehensive research project aimed at developing a reliable geotechnical model of the heterogeneous and highly stratified venetian lagoon basin the project included the construction of a full scale vertical walled cylindrical test bank together with a detailed monitoring system of surface settlements pore water pressures subsoil strains and stresses beneath the loaded area the analysis of the large amount of data thus available referring to different phases of the loading history confirms the great potential of piezocone as an in situ testing technique especially for stratigraphic profiling of the predominantly silty subsoil of the venetian lagoon but at the same time reveals some limitations of widely used empirical correlations for the relevant soil characterization with special reference to compressibility and conso

near surface mapping using sh wave and p wave seismic land streamer data acquisition in illinois u s human activities have considerable impact on the upper 300 m of sediments of the earth conflicting activities in highly populated areas involving groundwater exploitation aggregate extraction and hazardous chemical related production and storage induce stress on the environment nearly half the population living around the great lakes depends on shallow groundwater aquifers a coalition of four great lakes states illinois indiana michigan and ohio in conjunction with the u s geological survey has initiated a program to map this sensitive upper 300 m layer as part of this effort the illinois state geological survey isgs has undertaken the task of preparing 3d quadrangle maps of the upper 100 m of the entire state at a scale of 1 24 000 although large scale maps indicating potential aquifer contamination already exist figure 1 very little is known about the groundwater pathways through the upper sedimentary column which mainly consists of deposits from the quaternary continental glacier

probabilistic characterization of 2d soil profile by integrating cpt with masw data in situ laboratory and geophysical tests are currently used in site characterization these tests explore different parts of a site measuring different engineering properties at different resolutions scales the test results are then used to derive a design profile in traditional approaches the positions of boundaries between geological units are identified first and the soil profile is divided into several layers constant engineering properties are assigned to each geological unit and the variabilities within each layer are ignored to take the uncertainties into account characteristic design values are assigned there are no commonly accepted guidelines for choosing design values however which introduces additional subjective uncertainties this paper proposes a probabilistic site characterization approach based on bayesian statistical methods that allows a design profile involving uncertainty to be determined automatically the derived soil profile is not modelled by uniform layers but

landform characterization using geophysics recent advances applications and emerging tools abstract this paper presents an overview of the strengths and limitations of existing and emerging geophysical tools for landform studies the objectives are to discuss recent technical developments and to provide a review of relevant recent literature with a focus on propagating field methods with terrestrial applications for various methods in this category including ground penetrating radar gpr electrical resistivity er seismics and electromagnetic em induction the technical backgrounds are introduced followed by section on novel developments relevant to landform characterization for several decades gpr has been popular for characterization of the shallow subsurface and in particular sedimentary systems novel developments in gpr include the use of multi offset systems to improve signal to noise ratios and data collection efficiency amongst others and the increased use of 3d data multi electrode er systems have become popular in recent years as they allow for relatively fast and detailed mapping novel developments include time lapse monitoring of dynamic processes as well as the use of capacitively coupled systems for fast non invasive surveys em induction methods are especially popular for fast mapping of spatial variation but can also be used to obtain information on the vertical variation in subsurface electrical conductivity in recent years several examples of the use of plane wave em for characterization of landforms have been published seismic methods for landform characterization include seismic reflection and refraction techniques and the use of surface waves a recent development is the use of passive sensing approaches the use of multiple geophysical methods which can benefit from the sensitivity to different subsurface parameters is becoming more common strategies for coupled and joint inversion of complementary datasets will once more widely available benefit the geophysical study of landforms three cases studies are presented on the use of electrical and gpr methods for characterization of landforms in the range of meters to 100 s of meters in dimension in a study of polygonal patterned ground in the saginaw lowlands michigan usa electrical resistivity tomography was used to characterize differences in subsurface texture and water content associated with polygon swale topography also a sand filled thermokarst feature was identified using electrical resistivity data the second example is on the use of constant spread traversing cst for characterization of large scale glaciotectonic deformation in the ludington ridge michigan multiple cst surveys parallel to an 60 m high cliff where broad 100 m synclines and narrow clay rich anticlines are visible illustrated that at least one of the narrow structures extended inland a third case study discusses internal structures of an eolian dune on a coastal spit in new zealand both 35 and 200 mhz gpr data which clearly identified a paleosol and internal sedimentary structures of the dune were used to improve understanding of the development of the dune which may shed light on paleo wind directions

halogens in volcanic systems the transport degassing and atmospheric release of halogens from active volcanism on earth have been the focus of increasing interest over the last few decades and have recently been the subject of the 1st workshop on halogens in volcanic systems and their environmental impacts that was held in december of 2007 at yosemite lodge in yosemite national park california as an introduction to this chemical geology special issue collecting contributions from many of the participants at the workshop we review here recent advances in this field including experimental and theoretical investigations of halogen behaviour in volcanic and related magmatic systems we discuss previous research on several aspects of halogen geochemistry including halogen abundances in the mantle and magmas on earth the effects of halogens on phase equilibria and melt viscosities their partitioning between melt and fluid phase s upon decompression cooling and crystallisation of magmas in the earth s crust and their final atmospheric release as volcanic gases the role of halogens in the genesis of hydrothermal systems and in the transport of ore forming metals is also reviewed and we discuss our current understanding of atmospheric processing of volcanic halogens in both the troposphere and stratosphere and their consequent impacts in spite of these recent advancements our current understanding of halogen geochemistry at active volcanoes is still far too fragmentary and the key questions that require answers from future research are summarised in our conclusions

compressibility and monotonic shearing behaviour of toronto peat abstract the shearing behaviour of organic soils such as peat under monotonic loading can be very different than those of inorganic soils due to the presence of fibers a series of one dimensional consolidation direct simple shear and bender element tests are conducted to investigate the compressibility and the monotonic shear strength of a peat deposit from the port lands area of toronto ontario canada laboratory specimens are trimmed from block samples collected from a depth of about 4 0 to 4 5 m the samples organic content ranges from about 42 to 60 with a fiber content of 20 to 30 because of their moderate organic and water 180 237 contents the peat samples are found to be less compressible with a slower consolidation rate than several other surficial peat deposits reported in the literature all samples exhibit a ductile shearing behaviour with undrained strength ratios ranging from 0 32 to 0 57 and a residual effective friction angle of about 30 the monotonic tests are further examined within the framework of critical state soil mechanics bender element measurements are used to develop empirical relationships between several engineering parameters of toronto peat with shear wave velocity

microstructural observations of shear zones in sensitive clay abstract the present work assesses the structure and evolution of shear zones in sensitive quick clays from the initiation to the well established state this assessment is done by utilizing laboratory and small scale field experiments combined with the analysis of thin sections in light microscopy and sem high resolution x ray tomography micro ct is also applied in combination detailed 2d and 3d visualization of the shear zones is achieved shear zones are suggested to be formed in mm thick continuous fields of displacement with increasing shear displacement sets of micron sized minor shears develop within the main shear zone these initiate terminate and merge both in the plane and out of the plane directions the minor shears are characterized by distinct particle reorientation where the flaky clay particles and mica grains are aligned parallel to the direction of shear a porosity reduction is observed in the minor shears this is a direct observation of material contractancy and implies migration of water from the shear zone into the undisturbed matrix the width of the main shear zone is considered to be related to the applied rate of shear while the minor shears have a width determined by the micro texture of the sediment the observed multi scale structure of the shear zones which is governed by complex inner mechanics is challenging the smooth shear zone concept that is commonly applied in numerical simulations this is motivating a further improvement of such tools and the testing of other types of clay sediments

relationship between shear wave velocity and geotechnical parameters for norwegian clays abstracta database of shear wave velocity vs measurements using a variety of techniques and soil properties measured on high quality samples for 28 norwegian sites has been established the purpo

shear wave velocity as function of cone penetration test measurements in sand and silt mixtures abstract a database of research quality piezocone test cptu results and shear wave velocity v s measurements assembled in the context of an ambitious research project carried out at the treporti test site venice italy has been interpreted in order to study the seismic response of the predominantly silty sediments forming the venetian lagoon basin as well as to explore potential correlations for such intermediate soils the experience gained so far with the treporti database and other field data collected in the lagoon area has shown that the mechanical behavior of venetian soils cannot be easily interpreted using the existing and well established cptu based approaches hence the interest in examining whether or not the seismic response of these sediments expressed in terms of shear wave velocity follows the framework published for other soils the applicability to the available data of a number of existing correlations originally developed either for sands or fine sediments has been first investigated and updated relationships have been then suggested furthermore the small strain stiffness calculated from v s measurements has been compared with the field stiffness derived from the observed performance of a full scale test embankment built in the treporti site so as to verify common design assumptions the verification and calibration of existing approaches are likely to constitute a useful contribution to the practice of geotechnics not only in the venetian lagoon area but also in the silty deposits usually present in the surrounding alluvial plain and other similar depositional environments allowing rapid estimates of seismic soil classification as well as small strain stiffness properties for preliminary design or at sites where only cone penetration data are available

effect of sample disturbance on triaxial and oedometer behaviour of a stiff and heavily overconsolidated clay the tests in this investigation were performed on a natural soft clay with plasticity index around 32 which was k0 consolidated to a vertical stress of 2942 kpa and then k0 unloaded to a vertical stress of 74 kpa i e to the in situ stress the specimens so created were disturbed in various ways to study the effect of sample disturbance on the stress strain relationships during undrained shearing and during drained k0 loading i e k0 triaxial and oedometer tests the results for two testing alternatives may be summarized as follows alternative 1 allow the specimen to swell at the correct in situ effective stresses but accept an initial water content that is higher than the in situ value this alternative was found to give the best stress strain relationships around the in situ effective stresses for undrained triaxial tests but with undrained shear strength values up to about 20 too low due to the swelling taking place during consolidation to the in situ effective stresses alternative 2

a microelectromechanical system digital 3c array seismic cone penetrometer a digital 3c array seismic cone penetrometer has been developed for multidisciplinary geophysical and geotechnical applications seven digital triaxial microelectromechanical system accelerometers are installed at 0 25 m intervals to make a 1 5 m long downhole seismic array the accelerometers have a flat response up to 2 khz the seismic array is attached to a class 1 digital seismic cone which measures cone tip resistance sleeve friction pore pressure and inclination the downhole 3c array can be used together with impulsive seismic sources and or high frequency vibrators that are suitable for high resolution shallow applications results from two field experiments showed that a good data quality including a constant source function within an array and a dense depth sampling allowed robust estimation of seismic velocity profiles in the shallow subsoil using horizontal and vertical seismic sources downhole 9c seismic array data can be easily acquired the quality of the shear wave data is much superior when the surface seismic source is a controlled high frequency vibrator in stead of a traditional sledge hammer a remarkable correlation in depth in a fine scale between low strain seismic shear wave velocity and high strain cone tip resistance could be observed the array measurements of the full elastic wavefield and the broad spectral bandwidth are useful in investigating frequency dependent seismic wave propagation in the porous near surface soil layers which is informative of the in situ fluid flow properties stable estimates of dispersive seismic velocity and attenuation can be obtained

shear bands in undrained plane strain compression of norwegian quick clays this work presents the results of plane strain tests carried out at the laboratoire 3sr grenoble france on undisturbed samples of very sensitive norwegian soft clay discussion of the results focuses on the observed failure mechanisms and zones of localized deformation the tested clay is defined as quick clay because it liquefies completely upon remolding thus careful handling was necessary and original procedures were developed to place samples in the plane strain testing device with minimum disturbance results show that excess pore water pressure had developed during shear loading and shear strength was lost after the peak which is a typical phenomenon in sensitive soils the sample was held between two glass plates to enable visual tracking of the deformations a digital image correlation analysis revealed a complex pattern of emerging shear bands with one or two bands dominating and providing a final failure mechanism two local pore water pressure transducers were attached to the sample boun

chemical diffusion of fluorine in melts in the system na2oal2o3sio2 the volatilization of fluorine from three melts in the system na2oal2o3sio2 has been investigated at 1 atm pressure and 1200 1400 c the melts chosen have base compositions corresponding to albite jadeite and a peraluminous melt with 75 mole sio2 melt spheres were suspended from platinum loops in a vertical tube furnace in a flow of oxygen gas then quenched sectioned and analysed by electron microprobe the microprobe scans indicate that transport of fluorine to the melt vapor interface is by binary concentration independent interdiffusion of fluorine and oxygen fo interdiffusivity increases in the order albite peraluminous jadeite there is no simple reciprocal relationship between fo interdiffusivity and melt viscosity comparison with data on high pressure interdiffusivity of fluorine and oxygen in jadeite melt indicates that fo interdiffusivity increases with pressure from 0 001 to 10 kbar while the activation energy remains unchanged fluorine chemical diffusivity in albite melt is substantially lower than h2o chemical diffusivity in obsidian melts suggesting that different diffusive mechanisms are responsible for the transport of f and h2o in igneous melts fluorine diffuses in albite melt via an anionic exchange with oxygen whereas water probably diffuses in obsidian melt via an alkali exchange mechanism

coupled caal nasi diffusion in plagioclase feldspar experiments and applications to cooling rate speedometry abstract the rate of caal nasi interdiffusion in plagioclase feldspar was determined under 1 atm anhydrous conditions over the temperature range 1400 to 1000 c in calcic plagioclase an80 81 by homogenizing coherent exsolution lamellae the dependence of the average interdiffusion coefficient on temperature is given by the expression d 10 99 cm 2 sec exp 123 4 kcal mol rt t in k this value is for diffusion perpendicular to the 03 1 interface of the lamellae caal nasi interdiffusion is 4 to 5 orders of magnitude slower than oxygen diffusion in the temperature range 1400 to 1200 c and possibly 10 orders of magnitude slower at subsolidus temperatures the large differences in diffusion rates explain the apparent contradiction posed by the plagioclases of large layered intrusions e g the skaergaard which retain delicate ca na compositional zoning profiles on the micron scale but have undergone complete oxygen isotopic exchange with heated meteoric groundwater from the surrounding wall rocks caal nasi diffusion is slow the closure temperature is high within the solidus liquidus interval and ca na zoning is preserved oxygen diffusion is faster the closure temperature is lower 350 400 c and the feldspars exchange oxygen with the low temperature hydrothermal fluids the complex micron scale oscillatory zones in plagioclase can also be used as cooling rate speedometers for volcanic and plutonic plagioclase cooling histories typical of large mafic intrusions e g the stillwater are slow begin at high initial temperatures 1200 c and result in homogenization of oscillatory zones on the scale of 10 microns the oscillatory zones found in the plagioclase of granodioritic plutons are preserved because cooling is initiated at a lower temperature 1000 c limiting diffusion to submicron length scales despite the slow cooling rate of the intrusion

influence of early diagenesis on geotechnical properties of clay sediments romania black sea abstract the geotechnical properties of clay sediments were investigated using laboratory and in situ measurements as part of the geohazard assessment in the romanian sector of the black sea affected by landslides and seafloor deformation features the sediments were characterized as predominantly high plastic silty clay of high compressibility low undrained shear strength low cohesion and moderate sensitivity a shallow increase in shear strength exceeding the general trend could have been reconciled with evidence for the precipitation of iron sulfides and calcium carbonates related to early diagenetic reactions of sulfate reduction e g cryptic sulfur cycle and anaerobic oxidation of methane comparison of the compression behaviour of natural and reconstituted samples indicated that precipitation of these materials at particle contacts produced cementation the analysis of deeper sediments sharing similar geochemical properties illustrated that the early precipitation of even low quantity of sulfur and carbonate cements allowed clays to develop sufficient strength to preserve an abnormal high water content even under tens of meters burial depth because this cementation process was observed to be associated with an enhanced sensitivity and a strain softening response to undrained shearing it was concluded that such early diagenesis should be considered as a key environmental factor leading to weak layer formation that may influence the susceptibility of seafloor to failure

effects of mass wasting on the stratigraphic architecture of a fjord valley fill correlation of onshore shear wave seismic and marine seismic data at trondheim norway abstract a combined record of onshore high resolution shear wave seismic and marine p wave seismic data shows the near shore stratigraphic organisation of a fjord valley fill at trondheim central norway the overall stratigraphy shows a typical fjord valley fill of up to 160 m in thickness that is composed of glaciomarine and fjord marine sediments overlain by deltaic deposits which in the onshore section are draped by an anthropogenic fill an interval characterised by low shear wave velocities below the onshore anthropogenic fills is shown by sampled drillings to comprise part clay and part organic deposits the seismic record reveals evidence of recurrent mass wasting events that include landslide debris turbidite deposits and channel features a chronological framework for the stratigraphy is provided by existing radiocarbon dates for local deglaciation and mass wasting events the combined onshore offshore datasets document the lateglacial to holocene development of an emerging fjord and delta system affected by major mass wasting events the architectural development of the younger part of the stratigraphy is interpreted as particularly affected by two known mass wasting events each involving several million m 3 of debris a thick layer of debris from a 3500 cal yr event probably resulted in a blockage of the subaqueous channels diversion of turbidity currents and deposition of lateral accretion packages whereby local fjord sedimentation temporarily increased a 2200 cal yr event resulted in a sudden reorganisation of the distributary system whereby distal delta sedimentation abruptly shifted north to northeastwards to an area temporarily subjected to marine erosion during fall of relative sea level the study adds to the understanding of landslides and low stiffness zones in the area of importance for near shore geohazard assessment the study also provides insight into the stratigraphic variability of fjord valley fills and highlights the interplay between fjord marine sedimentation marine abrasion delta progradation and mass wasting during late stages of fjord filling

prediction of long term settlement on soft clay using shear wave velocity and damping characteristics this paper presents a method of calculating long term settlement of a loaded pad on soft clay at klang selangor malaysia where the soil model is treated as an anelastic material of viscoelastic property initially an elastic shear modulus g value from shear wave velocity profiles of the seismic tests from spectral analysis of surface wave sasw and continuous surface wave csw tests was obtained a value of damping d at an equivalent elastic strain is then calculated from the hysteresis of the plate load tests corrected to equivalent strain using the damping strain formula the calculated elastic settlement and its equivalent damping are then used to calculate the long term settlement by applying the generalised viscoelastic formula comparisons to traditional methods of settlement predictions were made and the viscoelastic formula has shown better agreement to the observed settlement further modification of the settlement formula is introduced to improve the settlement accuracy to 10

geological and geotechnical characterisation for offshore wind turbine foundations a case study of the sheringham shoal wind farm abstract this paper characterises the soil conditions at the sheringham shoal wind farm in the north sea in the context of designing foundations for offshore wind turbines the purpose is to provide a realistic reference case study for research and practice in the emerging field of offshore wind energy the soil data was obtained between 2005 and 2008 in an investigation program involving field measurements and laboratory experiments the characterisation focuses on soil properties which are relevant for evaluating the performance of foundations for offshore wind turbines the soil profile at the sheringham shoal site consists of four main units two clay strata interbedded with a sand layer and underlain by a chalk bed the heavily overconsolidated state of the clays and the densely compacted state of the sand dictate the behaviour of these soils the chalk bed is characterised by varying degrees of weathering leading to significant variation in properties ranging from those typical for stiff soil to soft rock these four main units though differ considerably in soil composition share several common characteristics including high shear strength and high stiffness but their shear stiffnesses reduce significantly both at high mobilised static shear strength and at medium to high mobilised strength under cyclic loading the soil stiffness is an important input parameter for the design of offshore wind turbine foundations and hence the degradation of stiffness is an important issue at this wind farm a number of soil properties at the site show considerable variability which requires a specific foundation design tailored for each location in order to be both safe and cost effective

field evaluation of deformation characteristics of a lacustrine clay deposit using seismic piezocone tests abstract the use of the seismic piezocone test scptu in geotechnical site investigation offers direct field measurement on stratigraphy and soil behaviour compared with some traditional investigation methods such as drilling sampling and field inspecting method or laboratory test procedures scptu can greatly accelerate the field work and hereby reduce corresponding operation cost this paper presents the methods review to predict the constrained modulus m and to measure small strain shear modulus gmax from scptu data the capacity of current interpretation methods to predict the constrained modulus m was evaluated for lixia river lagoonal soils several sites in lixia river area were selected for this study in each site scptu tests were performed and the soundings of cone tip resistance qc sleeve friction fs pore pressure u2 and shear wave velocity vs were recorded the predicted m values obtained from the scptu interpretation methods were compared with the reference values determined from the laboratory consolidation tests results of this study showed that the sanglerat method was able to predict m better than the other methods two new correlations were also developed to predict m from the corrected cone tip resistance qt and the net cone tip resistance qn small strain shear stiffness can be tentatively estimated in the absence of direct measurement of shear wave velocity the reliable result was obtained using an association between gmax qt and pore pressure parameter bq compared to field downhole wave velocity measurements scptu can lead to a more reliable measurement of maximum stiffness profile with depth the stress strain strength response of the clays was evaluated by the maximum shear stiffness and undrained shear strength

depositional and geotechnical properties of marine clays in lianyungang china the mineralogy geochemistry and geotechnical properties of clay samples in lianyungang china are presented the correlations of depositional history depositional environmental and geotechnical properties are discussed a series of x ray diffraction tests show that the principal clay minerals of the soil are illite smectite mixed layer mineral and illite the geochemistry investigation results indicate that the pore water of the lianyungang marine clay is dominant by sodium the ph of the soils varies in the range of 7 8 to 8 9 the depositional environment is oxidation condition the correlations of the geochemistry with the geotechnical properties are examined by the statistic analysis

crystallization sequence of the upper border series of the skaergaard intrusion revised subdivision and implications for chamber scale magma homogeneity although it is one of the best studied layered mafic intrusions in the world the crystallization sequence of the skaergaard intrusion east greenland remains in debate in particular it has been argued that the crystallization sequence in the upper border series which crystallized downwards from the roof of the magma chamber differs from that in the layered series formed at the floor the proposed deviation would require chemical stratification of the magma and a reexamination of the crystallization sequence therefore has important implications for understanding the dynamics of the system here we examine a new sample set from the upper border series combining field observations petrography and anorthite contents of plagioclase with bulk rock ti v p cu and mn concentrations we demonstrate that the first phases on the liquidus were plagioclase and olivine followed by augite then ilmenite and magnetite simultaneously sulfides apatite and finally ferrobustamite now inverted to hedenbergite this crystallization sequence represents extreme differentiation along the tholeiitic trend and it mirrors those at the floor layered series and walls marginal border series we therefore propose a revised subdivision of the upper border series into equivalents of the subzones in the layered series denoted by apostrophes lza lzb etc moreover the first appearance of each of the cumulus phases occurs at similar plagioclase core anorthite contents the mirror images of the crystallization sequences and the anorthite contents of plagioclase cores in the three series imply that the skaergaard magma chamber solidified by in situ crystallization along the floor walls and roof from one largely homogenous convecting magma body

halogen diffusion in magmatic systems our current state of knowledge diffusion of halogens has the potential to influence petrogenetic processes in magma chambers and conduit degassing processes this contribution reviews our current state of knowledge concerning halogen diffusion and the influence of halogens on the diffusion of major elements in silicate melts the addition of halogens to silicate melts at common natural concentration levels will have little effect on the diffusion of major elements however the differences between the diffusivity of water the diffusivities of halogens and the diffusivity of sulfur are significant enough that during melt inclusion entrapment or during rapid bubble or crystal growth diffusive fractionation between water and the halogens and between halogens and sulfur are expected to occur and can influence the compositions of melt inclusions crystals and volcanic gases

effect of lateral heterogeneity in the soil column on shear wave velocity estimation by rayleigh wave inversion we conducted elastic wavefield modeling of shot gathers using soil column models with vertical and lateral velocity variations to study the dispersive behavior of rayleigh waves and the effect of lateral heterogeneity on the accuracy of rayleigh wave inversion for shear wave velocity estimation we also conducted a field experiment over an alluvial valley with soil column that thins out in the direction orthogonal to the valley axis from the model and field experiments we found that the dispersion characteristics of rayleigh waves are greatly influenced by the geometry of and lateral heterogeneities within the soil column nevertheless estimation of shear wave velocities within a soil column with lateral heterogeneity by rayleigh wave inversion is sufficiently robust and accurate for geotechnical applications

the internal magma reservoir of large intrusions revealed by multiphase rayleigh fractionation the fractionation progress of a crystallizing basaltic magma is recorded in the changing mineral compositions of binary solutions that form a part of plagioclase olivine and augite when such compositional data are plotted against an independent measure of progress such as volume they can often be described by a rayleigh equation that reveals details of the crystallization history a binary solution crystallizing by itself follows a path determined by the rayleigh exponent d 1 where d is the partition coefficient x1 x1 l x is mole fraction 1 is low melting component l is liquid s is solid in company with another phase however such a binary solution may follow a wide range of paths in an envelope about d 1 ranging from a f d 1 to b d 1 f where f is the fraction of the active phasecthe binary solution under consideration the upper limiting curve an extended fractionation path is given by a above whereas a full x2 depletion path b defines the lower limit this range of alternatives is here codified and supplemented by considerations of residual porosity the result is a rayleigh equation in five variables that can illuminate magmatic history including the probability of the existence of an internal reservoir that damps the depletion effect the range of paths can help to identify evidence for and causes of leading edge fractionation of ascending magma small packet crystallization pressure variations off cotectic excursions and oscillating modal variation

development of the submarine channel in front of the nidelva river trondheimsfjorden norway abstract the nidelva submarine channel is a 4 km long and up to 100 m deep erosional feature seaward of a former outlet of the river nidelva in trondheimsfjorden norway mechanisms of channel evolution and sedimentary processes associated to its development are revealed by analyzing the sea bed morphology and the stratigraphy of the fjord sediments based on high resolution seismic data swath bathymetry imaging and gravity cores seismic data suggest that the submarine channel is eroded into late pleistocene clays filling a bedrock depression a thick holocene deltaic succession overlay the glacio marine clays seismic facies suggest that turbidity currents likely initiated downcutting of the channel in the early holocene these flows were guided by sea bed morphology and bedrock exposures favouring confluence and acceleration the area was subjected to glacio isostatic rebound and rapid fall of relative sea level in the holocene this resulted in a fast delta progradation likely with an enhanced activity of delta derived sediment gravity flows promoting incision in mid to late holocene such flows including hyperpycnal flows were responsible for deep incision of the channel laminated clay rich beds are interpreted as deposited by the overspill of turbiditic flows along the channel and likely originate from large terrestrial quick clay slides in the last 2000 years erosive flows initiated by mass wasting along the coast controlled the evolution of the channel after the mouth of the nidelva river moved to a more easterly position in the embayment present slope failure along the channel flanks seems to be controlled by the distribution of the laminated clay rich layers in the stratigraphy

volatile heavy metal mobility in silicate liquids implications for volcanic degassing and eruption prediction abstract the volatilization of cd re tl pb sb and te from melts in the system cao mgo al 2 o 3 sio 2 cmas and na 2 o mgo al 2 o 3 sio 2 nmas has been investigated at 0 1 mpa and 1200 1350 c experiments were conducted in air using metal doped melts in pt crucibles analysis of quenched glasses by laser ablation inductively coupled plasma mass spectrometry la icp ms normal to the melt gas interface produced concentration profiles for cd re tl pb sb and te to which a semi infinite one dimensional diffusion model could be applied to extract diffusion coefficients d the melt was also doped with cu zn in mo sn and w but concentration profiles for these metals did not develop in the cmas composition at 1300 c the fastest diffusing element was cd having a log d cd 6 5 0 2 the slowest element was re with log d re 7 5 0 3 diffusivities of sb te pb and tl have intermediate values where log d sb 7 1 0 1 log d te 7 2 0 3 log d pb 7 1 0 2 log d tl 7 0 0 2 cm 2 s in the nmas composition log d re 6 5 0 2 log d sb 6 0 0 2 log d pb 6 1 0 1 log d tl 5 8 0 2 cm 2 s values for cd and te were not determined differences in diffusivity of volatile heavy metal ions to a melt gas interface lead to significant fractionation between these metals in magmas during degassing given the observed differences in cd and re diffusivities in the cmas composition we predict an increase in the normalized cd re ratio in the gas phase with increasing bubble growth rate monitoring of the cd re ratios in aerosols from degassing volcanoes may provide a tool for predicting volcanic eruption

in situ shear wave velocity from multichannel analysis of surface waves masw tests at eight norwegian research sites the multichannel analysis of surface waves masw technique which is used to determine shear wave velocity vs and hence small strain stiffness gmax has recently generated considerable interest in the geophysics community this is because of the ease of carrying out the test and analysis of the data the objective of this work was to assess the repeatability accuracy and reliability of masw surface wave measurements for use in engineering studies tests were carried out at eight well characterized norwegian clay silt and sand research sites where vs had already been assessed using independent means as well as being easy and quick to use the masw technique gave consistent and repeatable results and the masw vs profiles for the clay sites were similar to those obtained from other techniques reasonable results were also obtained for the silt and sand sites with the best result being obtained for the finer silt this work also confirms that masw vs clay profiles are comparable to those obtained

effects of sample disturbance and consolidation procedures on measured shear strength of soft marine norwegian clays after many decades of research the issue of sample disturbance is still important as regards to determining reliable and representative soil parameters for foundation design in soft clays parallel laboratory tests have been carried out on high quality block samples and ordinary piston tube samples from 12 deposits of soft norwegian marine clays undrained triaxial and direct simple shear dss tests on samples reconsolidated to the in situ effective stresses show that sample disturbance has a significant effect on the measured stress strain strength behaviour the more disturbed the sample the lower the shear stress at small strains and the higher the shear stress at large strains breakdown of the clay structure including cementation bonds is the assumed cause of lower shear resistance at small strains whereas at large strains the shear resistance is governed mainly by the water content which for soft clay samples reconsolidated to the in situ effective stresses will be lower and the strength t

further work on experimental plagioclase equilibria and the skaergaard liquidus temperature equilibria between plagioclase and ferrobasaltic melt in low pressure dry melting experiments can be demonstrated near the liquidus further analyses of melting experiments using optimized beam conditions reveals that previous data for understanding the skaergaard intrusion potentially suffered from the analytical inclusion of non equilibrated components in the average plagioclase compositions new reversal experiments demonstrate convergence between plagioclase rim compositions in melting and crystallization products for a ferrobasaltic melt and thus support equilibrium relations the new data set provides tighter bounds on experimental plagioclase composition and documents composition dependent partitioning of na and ca between plagioclase and melt application of the results to modeling the skaergaard requires only minor adjustments to the previously proposed liquidus temperatures and liquid line of descent

automated procedure for estimating vs30 utilizing p wave seismograms and its application to japan abstract we develop an automated procedure to estimate time averaged shear wave velocities in the upper 30 m of soil deposits vs30 rapidly and objectively based on initial p wave seismogram amplitudes in the radial and vertical directions we apply this procedure to 630 kiban kyoshin network stations in japan utilizing 9207 records it is clear that the estimates are in good agreement with real world measurements filtering records based on signal to noise ratio snr thresholds slightly improves vs30 estimation but a decrease in the number of records results in an inability to estimate vs30 at certain sites we propose bias correction models based on snrs and take off angles to facilitate vs30 estimation at numerous sites while maintaining suitable prediction performance we observe that the performance of the proposed method is similar to that of methods utilizing different types of proxies for various regions we successfully apply the proposed method to 989 kyoshin network stations utilizing 18 454 records and create a vs30 map for the entire area of japan

a critical comment on thy et al 2009b liquidus temperatures of the skaergaard magma the study by thy tegner and lesher thy et al 2009b is based on whole rock compositions in batch melting experiments at one atmosphere that have a very large temperature variation for a very small plagioclase compositional variation their steep t x slopes of up to 14 c an contrast with the overall regression for the intrusion of 4 c an this paradox can be evaluated by using separate tests for equilibrium in temperature and composition the issue of temperature is clouded by the presence of low temperature components in the beginning of melting experiments compositions of plagioclase and liquid are too close to each other compared to expectations from other experiments at 1 atm and at pressure a ruling hypothesis is perceived here to the effect that every t xpair represents a valid equilibrium between a liquidus composition and a solidus composition therefore by inversion each solidus composition defines a valid temperature its corollary is that all such pairs receive equal weight and can therefore be legitimately regressed together the thy et al 2009b regression is passed through the center of gravity of the data rather than through the extrapolated maximum liquidus points if the ruling hypothesis is falsified these approaches lose their validity upon testing it is falsified in temperature testing leads to consequences known to be false in composition a test for reproducibility in results also fails thereby falsifying the principle of stable equilibrium the falsifications are repeated in at least three ways the study results cannot furnish a valid thermal path for the fractional crystallization of skaergaard magma a selection of the highest temperature results comes closer to a realistic result based on comparison with earlier experiments that melted out the trapped liquid component of the skaergaard cumulates new experimental approaches at the liquidus are needed to help define temperatures and fractionation progress in the skaergaard intrusion

the differentiation of the skaergaard intrusion we find no support for the claim that the skaergaard magma followed the trend of common tholeiitic volcanic magmas such as those of iceland and the scottish tertiary the end product of differentiation was not a large mass of rhyolite but an iron rich silica poor liquid not unlike that deduced by wager in 1960 the proposal that a large mass of rhyolitic liquid occupied the upper levels of the intrusion finds no support in the field the thick series of ferrogabbos which became richer in iron and poorer in silica until they reached a field of immiscibility cannot be reconciled with crystallization of a large mass of felsic magma mass balance calculations that indicate otherwise are invalid because they fail to take into account large volumes of rocks that differ in composition from those assumed in the calculations while ignoring the existence of major units of the intrusion hunter and sparks propose that lavas in scotland and iceland are more relevant to the liquid compositions than rocks that are intimately associated with the intrusion their argument that the skaergaard intrusion followed a trend of silica enrichment that is universal to tholeiitic magmas is based on an incomplete knowledge of the rocks and faulty calculations of mass balance relations we agree that much remains to be learned about the skaergaard intrusion and the basic mechanisms of magmatic differentiation in this case however we are ready to hang our case on well established field relations and a mass of laboratory data for what must be the most intensely studied body of rock on earth

characterization on the correlation between shear wave velocity and piezocone tip resistance of jiangsu clays the small strain shear modulus of a soil is a fundamental parameter related to the mechanical behavior used in evaluation of dynamic behavior and seismic design of geotechnical structures the jiangsu soft clay is a lightly overconsolidated and sensitive clay of high plasticity in nature a research database of piezocone penetration test cptu and shear wave velocity vs information for jiangsu soft clays has been collected to study the small strain shear modulus relationships for these soils and to examine the potential use of cptu and vs data in combination for the purposes of characterizing these soils test data for sites are based on the laboratory testing performed on thin wall tube samples and high quality block samples improvements have been suggested to existing correlations between the small strain shear modulus go or vs and index properties for these soils for better prediction of these soil properties

multivariate correlation analysis of seismic piezocone penetration scptu parameters and design properties of jiangsu quaternary cohesive soils abstract a recent trend of geotechnical correlation analysis is to construct a multivariate distribution model to describe the multiple dependency characteristics of different soil parameters in this study the feasibility of this multivariate method to model the multivariate dependency of seven soil parameters including the undrained shear strength ratio overconsolidation ratio sensitivity normalized cone tip resistance normalized sleeve frictional resistance pore pressure parameter and normalized shear wave velocity is studied a database containing 372 sets of observations of these seven parameters is collected from 25 sites in the jiangsu province china two data transformations including the johnson system of distribution and box cox method were used in the construction of the multivariate model for the jiangsu cohesive soils the correlations derived from these two local models were compared with the compiled jiangsu database data points at other testing sites in china and database and correlations published in the literature for validation it was shown that the local models developed in this study were capable of the multivariate dependency of the soil parameters for the jiangsu cohesive soils whereas the global model developed in the literature tends to overestimate the uncertainties associated with the design parameters for the jiangsu soils a potential explanation is that the soil parameters in a local region were less variable with stronger correlations than those over the global sites due to the site specific effect however caution shall be taken if the local models for the jiangsu soils are used at other sites besides the johnson system of distribution is superior to the box cox transformation in the construction of the multivariate distribution model in the sense that the former is more effective to achieve the standard normal distribution especially for the soil parameters with a bounded distribution

use of piezocone to predict maximum stiffness of venetian soils a comprehensive geotechnical in situ and laboratory investigation into the soils forming the upper quaternary basin of the venetian lagoon has been carried out in addition to standard tests measurements of shear wave velocity were performed using crosshole seismic piezocone bender element system and resonant column tests despite the incompatible strain levels of the seismic and piezocone tests it is shown that piezocone tip resistance and excess pore pressure can be used for a preliminary estimate of the small strain shear modulus gmax for the venetian soils foreword flooding of the well known historic city of venice due to high tides is increasing in frequency as a consequence of both the natural and anthropic subsidence in the venice area and the eustatic sea level rise to prevent this construction of a mobile gate system located at the three lagoon inlets was pro posed at the end of the 1980s for the design of the gate foundations geotechnical inves tigations were carried out at the inlets and particularly in a limited area at the malamocco inlet herein called the ma lamocco test site mts several types of in situ tests in cluding crosshole tests cht and seismic piezocone tests scpt were performed on contiguous verticals ministero dei lavori pubblici 1994 the geotechnical laboratory inves tigation also included bender element bet and resonant col umn tests rct on high quality undisturbed samples obtained using a large diameter 220 mm sampler field and laboratory test results are considered here with the aim of relating g

potential improvements of design parameters by taking block samples of soft marine norwegian clays undrained triaxial and direct simple shear tests on samples reconsolidated to the in situ effective stresses and oedometer tests have been carried out on standard piston tube and on high quality bl

tenth canadian geotechnical colloquium recent developments in consolidation of natural clays a global analysis of the consolidation of natural clays is realized considering the consolidation process to be a combination of the effects of compressibility and of permeability the compressibil

geophysical and geotechnical studies of geology and sediment properties at a quick clay landslide site at esp trondheim norway abstract increased urbanisation and development in previous marginal areas have led to the need to protect the population the environment and infrastructure from hazards such as quick clay landslides in this paper the opportunity which was presented following the gathering of a large amount of data in the area of the quick clay landslide at esp trondheim norway in 2012 is explored the data is of particular interest given the availability of frequency domain helicopter borne electromagnetic data fhem and extensive lidar imaging as well as a full range of in situ geophysical and geotechnical soundings and samples the ground conditions in the area are shown to be complex and it is clear that a multi disciplinary type approach combining geophysical geomorphological and geotechnical investigations is necessary in order to understand the hazards posed by potential quick clay landslides the investigation shows that very good overview mapping of the area can be obtained from fhem and that the data obtained from local electrical resistivity tomography ert and resistivity cone rcptu are consistent with each other and with the fhem data use of ert immediately after the landslide was particularly useful in delineating further risk areas and as an aid for assessment of evacuation of the local population lidar data is particularly useful in understanding the landslide trigger mechanisms the depth of the landslide the form of the run out and the nature of the material in the run out geotechnical data collected in the area is characteristic of that of soft sensitive norwegian marine clays and the various geotechnical and geophysical parameters correlate well with one another and also follow well established patterns the data shows that no single investigative method is available to accurately define quick clay layers but that a number of complimentary in situ and laboratory techniques are necessary for that purpose

effect of quaternary transgression and regression on the engineering properties of shanghai soft clays abstract the engineering properties of marine clays are closely related to its depositional environment however the correlation between the chemical properties and depositional environment and their effect on engineering properties of upper shanghai marine clay are still pending the sedimentary processes of upper shanghai marine clays from the quaternary transgression the correlation between the chemical properties and its depositional history are investigated in this study based on a series of laboratory experiments the distribution of chemical indicators e g ph value oxidation reduction potential and salt content with depth showed that the depositional environment directly affected the chemical properties of the soil layer the correlation of salt content with sensitivity liquid limit and liquidity index in upper shanghai layers represents a unique two stage distribution with the boundary at the bottom of the layer 4 clay the two stage distribution is caused by the quaternary transgression and regression which is confirmed to have different effects on the salt content sensitivity liquid limit and liquidity index the quantitative approaches used to evaluate the correlation between depositional environment chemical and mechanical properties can provide valuable references for investigating the engineering properties of soft clays

high resolution shear wave seismics across the carlsberg fault zone south of copenhagen implications for linking mesozoic and late pleistocene structures abstract the carlsberg fault zone cfz is a nnw sse striking structure close to the transition zone between the danish basin and the baltic shield we examine the fault evolution by combining very high resolution onshore shear wave seismic data one conventional onshore seismic profile and marine reflection seismic profiles the faulting geometry indicates a strong influence of triassic subsidence and rifting in the central european basin system growth strata within the cfz surrounding hollviken graben reveal syntectonic sedimentation in the lower triassic indicating the opening to be a result of triassic rifting in the upper cretaceous growth faulting documents continued rifting these findings contrast the late cretaceous to paleogene inversion tectonics in neighboring structures such as the tornquist zone the high resolution shear wave seismic method was used to image faulting in quaternary and danian layers in the cfz the portable compact vibrator source elvis iii s8 was used to acquire a 1150 m long seismic section on the island amager south of copenhagen the shallow subsurface in the investigation area is dominated by quaternary glacial till deposits in the upper 5 11 m and danian limestone below in the shear wave profile we imaged the uppermost 30 m of the western part of cfz the complex fault zone comprises normal block faults and one reverse block fault the observed faults cut through the danian as well as the quaternary overburden hence there are strong indicators for ongoing faulting like mapped faulting in quaternary sediments and ongoing subsidence of the eastern block of the cfz as interpreted by other authors the lack of earthquakes localized in the fault zone implies that either the frequency of occurring earthquakes is too small to be recorded in the observation time span or that the movement of the shallow sub surface layers may be due to other sources than purely tectonic processes

on the use of the norwegian geotechnical institute s prototype seabed coupled shear wave vibrator for shallow soil characterization ii joint inversion of multimodal love and scholte surface waves summary seismic data generated by a novel seabed coupled shear wave vibrator prototype and recorded by a densely populated multicomponent ocean bottom cable allowed several modes of propagation of love and scholte waves to be retrieved in a relatively wide frequency band both global dispersion curves and local dispersion curves are extracted in the frequency wavenumber f k domain and inverted with a multimodal joint scholte and love wave inversion algorithm monte carlo inversion is used for a estimating the global s wave velocity profile of the seabed sediments whereas laterally constrained inversion is used to detect lateral variations of the layer interface depths the results are in agreement and allowed consistent full waveform simulation to be performed the investigation depth is limited to around 40 m due to the low shear wave velocities within the shallow clay layer