diffusion of ti and some divalent cations in olivine as a function of temperature oxygen fugacity chemical potentials and crystal orientation the diffusion of titanium along with ni co and mn in pure synthetic forsterite has been studied as a function of temperature oxygen fugacity crystallographic orientation and chemical potentials in the four component system mgo sio2 tio2 tio1 5 in over 100 different experimental conditions no ti diffusion profiles with the classical shape of the error function were observed instead the profiles vary between stepped at high fo 2 probably owing to diffusion on octahedral sites and trapping in tetrahedral sites to hockey stick shapes at low fo 2 owing to concentration dependent diffusion the profile shapes vary systematically between these end members according to oxygen fugacity these profile shapes are also reproduced in experiments using natural san carlos olivine the change in profile shape is interpreted to be a function of valence state change from ti4 to ti3 shown by a sigmoidal log fo 2 diffusivity relationship to distinguish between ti4 to ti3 in forsterite a diffusion profile was also investigated using hydroxylation spectroscopy whereby a crystal from a diffusion experiment was hydroxylated by annealing in an h2o rich fluid at moderate pressure and temperature the point defects associated with the added structural oh were then determined by infrared spectroscopy providing evidence for the presence of ti4 to ti3 at intermediate oxygen fugacity the transition from ti4 to ti3 occurs at considerably higher fo 2 in these diffusion experiments than in equilibrium experiments in similar systems titanium diffusion qualified using a mobility parameter m is fastest along the c axis at high activity of silica low oxygen fugacity and high temperature the rate of ti diffusion is broadly similar to those of mn ni and co and closer to published rates ofmg self diffusion in olivine than si self diffusion the observed ti4 to ti3 diffusion occurs on the m sites from statistical examination of the large mn ni and co diffusivity dataset we determine that there is a 10 2 3 dependence of diffusion on asio 2 the cations diffuse more rapidly at high asio 2 in addition diffusivity has a 10 1 8 dependence on fo 2 suggested to be the result of increased concentration of loosely bound ti3 vacancy pairs which enhance the mobility of other cations this behaviour is likely to be present in natural systems where trivalent e g fe3 al3 cr3 and divalent cations diffuse together consideration should be given to diffusive interference by highly charged fast moving cations when extracting time scales from frozen diffusion profiles

factors controlling geochemical and mineralogical compositions of coals preserved within marine carbonate successions a case study from the heshan coalfield southern china abstract the late permian coals in the heshan coalfield of southern china are preserved within marine carbonate successions and characterized by super high organic sulfur 5 13 10 82 minerals identified in the coals include quartz kaolinite illite mixed layer illite smectite albite pyrite marcasite calcite and dolomite along with trace amounts of smectite fluorite strontianite rey bearing carbonate minerals jarosite and water bearing fe oxysulfate the coals are very rich in trace elements including f up to 3362 g g v up to 270 g g se up to 24 4 g g mo up to 142 g g u up to 111 g g and to a lesser extent sr y zr nb cd cs heavy rare earth elements hf ta w hg and th previous studies attributed the high organic sulfur and elevated trace elements to the seawater influence or the formation of soil horizons before the accumulation of peat in the basin however mineralogical and geochemical data presented in this study have shown that the sediment source region and multi stage hydrothermal fluids are the dominant influences on the mineralogical composition and elevated trace elements in the coal although seawater influence also contributed to the composition of the mineral matter for example a large proportion of the quartz and clay minerals as well as almost all the albite in both the coal benches and the parting mudstones were derived from detrital materials of terrigenous origin in the yunkai upland high concentrations of lithophile trace elements were also derived from the sediment source region minerals including fluorite calcite dolomite strontianite and rey bearing carbonate minerals were derived from multi stage hydrothermal activities high concentrations of v mo and u that occur through the coal seam sections were probably derived from hydrothermal solutions during peat accumulation or at the early diagenetic stages the hydrothermal fluids also corroded the syngenetically formed minerals quartz albite and pyrite and caused re distribution of lithophile elements from partings to the underlying coal benches resulting in higher key element ratios yb la nb ta and zr hf and more abundant heavy rare earth elements in the coal benches than in the immediately overlying partings

hydrous melts weaken the mantle crystallization of pargasite and phlogopite does not insights from a petrostructural study of the finero peridotites southern alps abstract this study reports petrostructural observations in the pargasite and phlogopite bearing finero peridotite massif italian western alps which suggest that the pervasive foliation in this massif was formed by deformation concomitant with percolation of hydrous si rich melts 1 diffuse contacts but systematic parallelism between the pyroxenitic layers and the foliation of the peridotite 2 strong shape and crystal preferred orientations spo and cpo but subhedral or interstitial shapes and weak intracrystalline deformation of the hydrous phases 3 cpo but interstitial shapes of the pyroxenes 4 very coarse olivine grain sizes which are correlated to the olivine abundance and 5 elongated shapes but weak intracrystalline deformation and extremely weak and highly variable cpo of olivine the pervasive deformation of the finero peridotite occurred therefore under conditions that allowed coexistence of h2o co2 bearing melts pargasite and spinel that is temperatures of 980 1080 c and pressures

fingerprinting the water site in mantle olivine nominally anhydrous minerals such as olivine contain trace amounts of water and may accommodate the entire water budget of the upper mantle here we report for the first time synthetic olivines crystallized experimentally under upper mantle conditions that reproduce the most common and intense infrared hydroxyl stretching bands at 3572 and 3525 cm 1 observed in spinel peridotite mantle olivines these bands arise from water accommodated at point defects associated with the trace element ti and we suggest that this is the most important defect site in the shallow upper mantle additional hydrated defects may occur at higher pressures we also identify bands related to water associated with fe3 these are unlikely to reflect equilibrium with the mantle and indicate water incorporation during exhumation or retrogression water must be present at the defect site appropriate for the mantle at the conditions of interest for partitioning seismic wave speed and deformation experiments on hydrous olivine to be relevant

concentration and distribution of elements in late permian coals from western guizhou province china abstract with the aim of better understanding geochemistry of coal 71 late permian whole seam coal channel samples from western guizhou province southwest china were studied and 57 elements in them were determined the contents of al ca co cr cu fe ga hf k li mn mo nb ni sn ta ti th u v zr and rees in the late permian coals from western guizhou province are higher than the arithmetic means for the corresponding elements in the us coals whereas as ba br f hg p se and tl are lower compared to common chinese coals the contents of co cr cu ga hf li mn mo ni sc sn ti u v zn and zr in western guizhou coals are higher and as f hg rb sb tl and w are lower five groups of elements may be classified according to their mode of occurrence in coal the first two group a tm yb lu y er ho dy tb ce la nd pr gd sm and group b as sr k rb ba f ash si sn ga hf al ta zr be th na have high positive correlation coefficients with ash yield and they show mainly inorganic affinity some elements from group b such as ba be ga hf and th are also characterized by significant aluminosilicate affinity in addition arsenic also exhibits high sulfide affinity r s fe 0 5 the elements which have negative or lower positive correlation coefficients with ash yield with exceptions of bi cs nb mn se and ti are grouped in other four associations group c cr v mo u cd tl group d hg li sc ti eu nb cs w group e bi sb and group f co ni cu pb zn mg se ca mn s fe the correlation coefficients of some elements including co cr cu fe hg li mo ni p s sc u v and zn with ash yield are below the statistically significant value only cr and cu are negatively correlated to ash yield 0 07 and 0 01 respectively showing intermediate organic and inorganic affinity manganese and fe are characterized by carbonate affinity probably due to high content of epigenetic veined ankerite in some coals phosphorus has low correlation coefficients with any other elements and is not included in these six associations there are five possible genetic types of enrichment of elements in coal from western guizhou province source rock volcanic ash low temperature hydrothermal fluid groundwater and magmatic hydrothermal inputs

co2 ecbm field tests in the ishikari coal basin of japan abstract the feasibility of extracting gas from coal seam while storing carbon dioxide underground was evaluated in japan a co2 ecbm project had begun near the town of yubari on the island of hokkaido in northern japan the primary coal seam of interest was a 5 6 m thick yubari coal seam located at the depth of 900 m a micro pilot test with a single well and multi well co2 injection tests involving an injection and production wells were carried out in the period between may 2004 and october 2007 there were a variety of tests conducted in the injection well including an initial water injection fall off test and a series of co2 injection and fall off tests although gas production rate was obviously enhanced by co2 injection water production rate was not clearly affected by co2 injection several injection tests suggested that injectivity of co2 into the virgin coal seam saturated with water was eventually increased as the water saturation near the injector was decreased by the injected co2 it was estimated that low injectivity of co2 was caused by the reduction in permeability induced by coal swelling n2 flooding test was performed in 2006 to evaluate the effectiveness of n2 injection on improving well injectivity the n2 flooding test showed that daily co2 injection rate was boosted but only temporarily moreover the permeability did not return to the initial value after co2 and n2 were repeatedly injected it was also indicated that the coal matrix swelling might create a high stress zone near to the injection well

alpe arami a peridotite massif from depths of more than 300 kilometers the abundance of fetio 3 and chromite precipitates in olivine of the alpe arami peridotite massif switzerland requires a much higher solubility for highly charged cations than is found in mantle xenoliths from depths of 250 kilometers three previously unknown crystal structures of fetio 3 were identified that indicate that the originally exsolved phase was the high pressure perovskite polymorph of ilmenite implying a minimum depth of origin of 300 kilometers these observations coupled with the unique lattice preferred orientation of olivine further suggest that the original composition of olivine may reflect that of a precursor phase perhaps wadsleyite that is stable only at depths greater than 400 kilometers

occurrence of minerals within fractures and matrix of selected bowen and ruhr basin coals abstract late permian age samples of black coal from the coeval bandanna formation and baralaba coal measures of queensland s bowen basin as well as carboniferous coal from germany s ruhr basin were investigated this paper presents scanning electron microscope sem analysis of the mode of occurrence of minerals within these coals and characterisation of the natural fractures present within the samples the coal samples located proximal to orogenic fronts in both basins are structurally complex with multiple generations of mineralisation evident stable isotope analyses of carbonates from selected samples indicate that methanogenesis related co2 reduction has occurred at two of the bowen basin sampling locations ankerite precipitated from a magmatic fluid or basinal brine is associated with significant sulphide mineralisation within brecciated ruhr coal proximal to major fault intersections with anticlines and has been meteorically altered to ferroan calcite and sulphates in coal from immediately below the carboniferous cretaceous unconformity similar alteration has occurred within a bowen basin coal sample close to the present day land surface variation of mineralisation within both the cleats and the coal matrix occurs on a fine scale with crystals of multiple mineral species often being present within micrometres of each other

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

upwelling rebound ephemeral secondary pycnoclines and the creation of a near bottom wave guide over the monterey bay continental shelf several sequential upwelling events were observed in fall 2012 using measurements from the outer half of the continental shelf in monterey bay during which the infiltration of dense water onto the shelf created a secondary near bottom pycnocline this deep pycnocline existed in concert with the near surface pycnocline and enabled the propagation of near bottom cold semidiurnal internal tidal bores as well as energetic high frequency nonlinear internal waves of elevation iwoe the iwoe occurred within 20 m of the bottom had amplitudes of 8 24 m periods of 6 45 min and depth integrated energy fluxes up to 200 w m 1 iribarren numbers 0 03 indicate that these iwoe were nonbreaking in this region of the shelf these observations further demonstrate how regional upwelling dynamics and the resulting bulk cross margin hydrography is a first order control on the ability of internal waves at tidal and higher frequencies to propagate through continental shelf waters

the morning glory an extraordinary atmospheric undular bore summary observations made during an expedition in october 1980 to study morning glory wind squalfs in the gulf of carpentaria region of northern australia are described during a ten day period in burketown north queensland six squalls were documented on consecutive mornings 8 1 3 october including two moving from the south an apparently unusual direction the unique data gathered from the latter confirm that these have the same character as their north easterly counterparts that is they are undular bores the origin of southerly glories remains uncertain but at least in some cases appears to be linked with the northeast advance of a frontal trough across central australia while the data are equivocal it seems possible that the motion of the front into the developing nqcturnal inversion could generate waves or hydraulic type disturbances which run along the inversion layer ahead of the front as proposed by tepper 1950 the efficacy of such a mechanism is demonstrated by a simple laboratory experiment evidence is presented which suggests that morning glory type events occur elsewhere in the world sometimes as precursors to cold fronts observations in the gulf of carpentaria region show that they are effective triggers of deep convection when they advance into air with a sufficient degree of conditional instability

mineral occurrence and its impact on fracture generation in selected qinshui basin coals an experimental perspective abstract the effect of mineral matter on the fracture evolution was investigated for lower permian and upper pennsylvanian coal samples from the qinshui basin of china optical microscopy scanning electron microscopy with energy dispersive x ray spectrometry sem eds and x ray computed tomography x ray ct were used to investigate the composition and modes of occurrence of minerals within the coals and to characterize the natural and induced fractures present within the samples the spatial distribution of mineral matter investigated by x ray ct demonstrates that the variation of mineralization within the cleats fractures occurred at fine scales and most of minerals were scattered in coal core samples the original fractures normally were present as two sets one set was almost parallel to the bedding plane and the other was almost perpendicular to the bedding plane for created fractures the difference in density between the matrix and mineral matter may weaken the cohesion of coals and it could explain why the created fractures propagate along the junction of minerals and organic coal matrix the internal fracture porosities varied from 0 06 to 20 69 which indicates a strong internal heterogeneity of the coals after a stress is applied the inclination of the main shear fractures ranges from 55 to 95 using energy analysis the fracture energy appears to represent nearly half of the total dissipated energy which can be correlated with the fracture density and orientation the formation and distribution of shear fractures is related to the spatial distribution of mineral matter and the overall mineral content these investigations serve to characterize hydro fracturing and pulverized coal generation during coalbed methane development

extended planar defects and the rapid incorporation of ti 4 into olivine the formation of extended planar defects in minerals such as olivine is related to high point defect concentration and can be driven by large gradients in chemical potential where the energy of the system is lowered by the ordering of defects along specific planes in the crystal the presence of extended defects has the potential to create the apparently anomalous ionic diffu sion in olivine as reported recently spandler and o neill in contrib mineral petrol 159 6 791 818 2010 high resolution transmission electron microscopy and energy filtered imaging were done using experimental samples designed to examine the impact of atio2 and fo2 on the potential to form such defects in ferromagnesian olivine doped basalt 5 wt tio2 olivine reaction couple experiments were run at 1 atm and 1 310 and 1 410 c for 50 h at various fo2 ranging from 10 2 below to 10 2 above the quartz fayalite magnetite buffer our results show that extended planar defects in olivine parallel to 101 ol and occurring in ordered clusters with a prolate spheroid geometry 5 25 nm across and extending up to 150 nm into the olivine are present near the olivine glass inter faces in all of our experimental high tio2 basalt olivine samples increased ti content in the olivine is associated with the defects ordering of ti 4 and octahedral site vacancies leads to a two or three layer superstructure in the olivine defect nucleation and growth is driven by the large tio2 chemical potential gradient across the phase boundary at the start of the experiments which provides access to microstructures not otherwise present

observations of polarity reversal in shoaling nonlinear internal waves observations off the new jersey coast document the shoaling of three groups of nonlinear internal waves of depression over 35 km across the shelf each wave group experienced changing background conditions along its shoreward transit despite different wave environments a clear pattern emerges nearly symmetric waves propagating into shallow water develop an asymmetric shape in the wave reference frame the leading edge accelerates causing the front face to broaden while the trailing face remains steep this trend continues until the front edge and face of the leading depression wave become unidentifiable and a near bottom elevation wave emerges formed from the trailing face of the initial depression wave and the leading face of the following wave the transition from depression to elevation waves is diagnosed by the integrated wave vorticity which changes sign as the wave s polarity changes sign this transition is predicted by the sign change of the coefficient of the nonlinear term in the kdv equation when evaluated using observed profiles of stratification and velocity

the pressure disturbance of a nonlinear internal wave train observations from a lander fixed to the seafloor over the continental shelf in 124 m of water provide highly resolved velocity measurements through nonlinear internal waves of elevation from these measurements we determine for the first time the non hydrostatic pressure disturbance p nh in nonlinear internal waves for near bottom waves of elevation ranging in amplitude a from 12 to 33 m the value of p nh evaluated at the seafloor changes sign from 0 to and back in accordance with weakly nonlinear theory peak values of vert p nh vert range from 25 to 90 n m 2 the external hydrostatic pressure disturbance due to the surface displacement eta h is inferred from horizontal accelerations for elevation waves eta h peak values range from 0 1 to 9 mm 1 to 90 n m 2 the internal hydrostatic pressure perturbation p wh caused by isopycnal displacement is inferred from measured streamlines and an ambient density profile its value at the seafloor is 0 for elevation waves peak values range from 100 to 300 n m 2 vert eta h vert and seafloor values of vert p nh vert p wh all increase monotonically with a since vert p nh vert and p wh increase at roughly the same rate with a no clear trend arises in the degree to which waves become more or less non hydrostatic as a changes a distinct bottom pressure signature is determined for bottom trapped nonlinear waves of elevation a wave train consisting of a sequence of positive pressure perturbations dominated by p wh by inference a train of surface trapped nonlinear internal waves of depression will consist of a sequence of negative pressure perturbations a result of this analysis is that significant properties of the waves can be discerned from a simple adequately resolved bottom pressure measurement

experimental mineral dissolution in berea sandstone reacted with co2 or so2 co2 in nacl brine under co2 sequestration conditions a comparison of the geochemical changes induced in sandstone by either pure or impure co2 at geological co2 storage conditions was investigated samples of berea sandstone were batch reacted in 1 w v nacl brine saturated with pure co2 or mixed so2 co2 gas for 360 h at 50 degrees c and 10 mpa geochemical analysis of incremental water samples showed increases in the concentrations of elements such as calcium magnesium iron manganese and silicon throughout experiments likely being the products of carbonate and reactive silicate dissolution scanning electron microscope images taken of specific points of interest before and after batch reactions confirmed dissolution of carbonates but showed no reaction for minerals such as k feldspar the magnitude of apparent mineral reaction was higher for the mixed gas so2 co2 brine experiment with geochemical modelling also indicating greater dissolution of reactive silicates such as chlorite and potential precipitation of amorphous silica c 2014 elsevier b v all rights reserved

internal solitary waves in the warm pool of the western equatorial pacific abstract during the spring tides of late november 1992 early january and early february 1993 solitary internal wave packets were observed at 2 s 156 15 e in the western equatorial pacific apparently generated in the nuguria island group 3 s 153 e the waves propagate northeastward at 2 4 2 8 m s 1 appearing in fixed phase with the underlying semidiurnal baroclinic tide the initial solitary wave crests have downward displacements in excess of 60 m and peak velocities greater than 80 cm s 1 groups of 1 3 crests are observed with vertical structure resembling a first mode internal wave and horizontal variability consistent with third order comb kdv solitons many of the packets exhibit an overall organization reminiscent of undular bores this borelike behavior is confined primarily to the upper 70 m not sharing the mode one dependency of the crests the solitons displace the ambient equatorial currents including the equatorial undercurrent both vertically 80 m and laterally 1 2 km with l

fluorine partitioning between humite group minerals and aqueous fluids implications for volatile storage in the upper mantle phase equilibrium experiments were performed in the mgo sio2 h2o system along with fluorine msh f at conditions between 800 1000 c and 2 0 2 5 gpa to constrain the solubility of fluorine in humite group minerals and to determine fluorine partitioning between humite group minerals and aqueous fluid fluorine solubility in humite group minerals ranges between 1 and 11 wt f and is dependent on the salinity of the fluid 0 2 3 5 wt f indicating that humite group minerals have exceedingly high saturation limits for f and that a full solid solution between f and oh is possible within the crystal structure raman spectroscopy reveals the preferential ordering of f promoting the formation of a stable oh f bond mineral fluid partition coefficients are always greater than unity with average coefficients of d f clinohumite fluid 3 d f humite fluid 2 d f chondrodite fluid 4 and d f norbergite fluid 4 partition coefficients are independent of pressure or temperature but decrease with increasing fluid salinity fluorine is therefore highly soluble and compatible within this group of ultramafic mantle minerals high solubility and mineral fluid partition coefficients together with wide stability fields in pressure and temperature space demonstrate that humite group minerals are potential storage sites for f and by extension h2o during subduction upon the breakdown of less stable hydrous and or fluorine rich phases during lower grades of subduction zone metamorphism fluorine may redistribute into phases such as humite group minerals and be transported beyond the volcanic arc and to the upper mantle

oh bearing planar defects in olivine produced by the breakdown of ti rich humite minerals from dabie shan china the partial breakdown of ti chondrodite and ti clinohumite during exhumation from ultra high pressure to amphibolite facies conditions in garnet pyroxenites from dabie shan china produces coronas of olivine coexisting with ilmenite blebs fourier transform infrared ftir spectra of this newly formed olivine exhibit absorption bands in the hydroxyl stretching region two intense peaks were observed at 3 564 and 3 394 cm 1 identical in energy to peaks in ti clinohumite transmission electron microscopy tem of the same olivine domains revealed the presence of a complex 001 planar intergrowth these interlayers have a 1 35 nm repeat distance which is characteristic of clinohumite such interlayers are also enriched in ti with respect to the adjacent olivine as shown by energy dispersive spectrometry the combined evidence from ftir spectroscopy and tem indicates that oh is incorporated along ti clinohumite planar defects this study provides evidence that the nominally anhydrous phase olivine may contain oh as a humite type defect beyond the breakdown of the hydrous humite minerals and confirms earlier suggestions that ti plays a key role in oh incorporation in mantle olivine we suggest that olivine containing ti clinohumite defects is an important phase for water transport in subduction zones and for the storage of water in cold subcontinental mantle however these defects are unlikely to be stable in hotter parts of the oceanic mantle such as where basaltic magmas are generated

phase relations of a serpentine composition between 5 and 14 gpa significance of clinohumite and phase e as water carriers into the transition zone run products from high pressure experiments at 800 1 200 c and 5 14 gpa corresponding to depths of 150 to 420 km on a serpentine bulk composition close to mg3si2o5 oh 4 were analysed by optical microscopy micro raman spectroscopy and electron microprobe all charges exhibit strong chemical zoning fluid melt and hydrous solids were mostly concentrated at the top bottom and along the wall of the capsules the central part of the charge was devoid of h2o both fluid and hydrous magnesian phases exhibit a mg si ratio higher than forsterite in contrast the centre of the capsule was enriched in sio2 the observed zoning can neither be explained by gravitational settling nor by a thermal gradient alone most likely the fluid was separated from the solids by surface forces and thereby established the chemical gradient by preferentially dissolving mgo if strong chemical zoning is taken into account the occurrence of more phases than allowed by the phase rule can be explained by separating the bulk into several domains of different bulk compositions results indicate that small amounts of f increase the stability field of clinohumite mg9si4o16 oh f 2 compared to oh clinohumite in pure msh previously reported clinohumite coexists with enstatite up to 975 c at 5 gpa and up to 1 100 c at 12 gpa at 14 gpa close to the mg2sio4 transition phase e becomes the most important water carrier the new results indicate that clinohumite could be an important mantle mineral for transporting water into the earth s transition zone due to its high thermal stability compared to other important water carriers such as serpentine and phase a

titanium substitution mechanisms in forsterite abstract ti k edge x ray absorption near edge structure xanes and extended x ray absorption fine structure exafs spectra together with atomic scale calculations indicate that ti occupies the si site in anhydrous forsterite the energy and intensity of the 1 s 3 d transition in the xanes spectrum is diagnostic of ti on a four coordinate site the exafs spectra determine a ti o bond length of 1 81 0 01 a this value is in excellent agreement with that of 1 8 a determined computationally by periodic density functional theory and an embedded cluster approach for ti on the si site the calculated bond length for ti on a mg site is 2 0 a both computational methods further find that the direct substitution of ti for si is energetically favoured relative to substitution of ti for mg charge balanced by either a mg vacancy or mg on a si site together the results provide unambiguous evidence for ti occupying the si site in anhydrous forsterite ti bearing olivine synthesised at upper mantle conditions in the presence of water however exhibits a pre edge feature corresponding to six fold coordination this is consistent with the identification of a ti clinohumite like point defect in samples of olivine from upper mantle spinel peridotite the change in ti site thus provides a mechanism for the incorporation of water in olivine the total ti content of olivine will comprise varying contributions from mg 2 4 tio 4 and ti clinohumite like mg 6 tio 2 oh 2 substitutions

hydroxyl in olivines from mantle xenoliths in kimberlites of the siberian platform from a total of 335 olivine crystal grains crystallographically orientated platelets and where possible parallelepipeds were prepared chemically analysed by electron microprobe examined under the polarisation microscope and studied by polarised ftir microscope absorption spectrometry in the oh vibrational range 3 000 3 800 cm 1 the 335 crystal grains were extracted from 174 different specimens of yakutian upper mantle material including 97 xenoliths that represent all the rock types occurring in all the kimberlites of the siberian shield the other specimens were mega and macrocrysts or inclusions in diamonds and garnets analysis of the polarised oh spectra allowed distinction between hydroxyl in non intrinsic separate inclusions nsi and in isolated local or condensed extended defects intrinsic to the olivines ild or ced respectively as the two latter types cannot be distinguished by vibrational spectroscopy and as they are presumably interconnected by intracrystalline condensation reactions of the type n ild ced n we propose to symbolise them as ild ced of the total of 70 polarised oh bands that were found in the whole set 17 are caused by nsi 53 by ild ced total mean integrated oh band intensities int total with int a b c int 3 were determined from the spectra they yielded the contents of structurally unallocated water using the recent calibration of the ir method bell et al 2003 the range is 0 a b at 3 327 3 328 cm 1 an energy typical of oh in hydrous wadsleyite we assume this phase to be present as nis in the respective olivines possibly as relic phase 4 weak bands between 3 175 and 3 260 cm 1 polarised along c are tentatively assigned to molecular water nsi with relatively strong hydrogen bonds to the matrix we did not find larger clusters of molecular water i e liquid like water with its characteristic broad band centred at ca 3 400 cm 1 we did also not find any humite minerals as an nsi of the 53 oh bands intrinsic to olivine the 29 most abundant and strong ones were subject to further analysis in terms of oh bearing structural defects ild ced nearly all these bands are strongly polarised along a two bands at 3 672 and 3 535 cm 1 are assigned to boron related defects ild ced b five bands at 3 573 3 563 3 541 3 524 and 3 512 cm 1 are intensity correlated and are assigned to si depleted titan clinohumite like defects ild ced thl the other so far unidentified oh of ild ced are suggested to originate from oh in different types of mg fe depleted defects recently predicted and discovered by tem these are called ild ced kwk eight mostly strong bands of them occur at energies higher than 3 573 cm 1 ild ced kwk h 13 strong to medium strong bands occur below 3 500 cm 1 ild ced kwk l such intrinsic defects may occur alone ild ced thl and ild ced kwk h or in different combinations with each other ild ced kwk h ild ced thl ild ced kwk h ild ced kwk l and ild ced kwk h ild ced thl ild ced kwk l though there are indications that the occurrences of such types and combinations of the intrinsic oh bearing defects in the olivines are related to the types and genetic peculiarities of their host rocks straightforward and simple correlations do not exist the reasons for this and also for the great number of varieties of intrinsic ild ced are discussed

new mineral names the following new minerals are discussed in this issue langbanshyttanite pseudolyonsite and yangzhumingite these new minerals have been described in the european journal of mineralogy and are reported here n v chukanov i v pekov e jonsson n v zubkova y e filinchuk d i belakovskiy and d yu pushcharovsky 2011 langbanshyttanite a new low temperature arsenate mineral with a novel structure from langban sweden eur j mineral 23 675 681 the new mineral langbanshyttanite was discovered in a specimen from the langban mine filipstad district varmland county bergslagen ore province sweden the carbonate hosted langban deposit 59 86 n 14 27 e is together with related occurrences in the western part of the palaeoproterozoic bergslagen ore province in south central sweden characterized by anomalously pb as ba be sb rich metamorphosed stratabound fe and mn oxide ores with associated skarn units sulfide assemblages as well as abundant vein and fissure hosted mineral assemblages the name is for langbanshyttan which is the old name of both the mine mining village and smelter that in more recent times has been known plainly as langban langbanshyttan actually means langban s smelter or langban s furnace langbanshyttanite occurs as a very late low temperature species in the deposit it crystallized during the last stage of hydrothermal activity involving metal remobilization in the langban system post dating regional metamorphism of the volcanic hydrothermal ores and their host rocks based on existing evidence these minerals formed at very low temperature and pressure in this case most likely below 70 c the mineral formed in fractures and corrosion veinlets post dating calcite in a mn oxide bearing mn silicate rich rock associated late stage minerals are calcite antigorite sparse euhedral trigonite and a few microscopic aggregates of a so far unidentified as bearing mineral typically both calcite and antigorite exhibit evidence of being partly corroded away prior to langbanshyttanite formation trigonite coeval with langbanshyttanite occurs as sparse euhedral crystals the groundmass to the veinlets or fractures mainly consists

sediment resuspension and mixing by resonantly generated internal solitary waves the observation of internal solitary waves isws propagating upstream along a strongly stratified bottom layer on the california shelf is reported an increased concentration of particulates in the water column accompanies the passage of these isw packets the estimated local richardson number in the bottom vicinity is around 1 4 and a vertical coefficient of eddy diffusivity of order 1022 m2 s21 is associated with the upstream propagating leading isw the leading isw gave rise to reversed flow in an 8 m layer above the bottom it is argued that the upstream propagating isws were generated by resonant flow over bottom topography internal waves generated in this way seem to be frequent in the record of a month long experiment model results suggest that the isws can carry up to 73 of such generated long wave energy the ocean conditions at the site are similar to those of other coastal sites which suggests that the phenomenon described here may be common

sediment resuspension mechanisms associated with internal waves in coastal waters 1 large amplitude vertically trapped internal waves can induce sizable velocities and trigger hydrodynamic instabilities in the bottom boundary layer thereby contributing to the resuspension of sediments and the maintenance of sediment concentration in the water column we discuss numerical simulations of several different situations in which the boundary layer in the wave footprint undergoes hydrodynamic instability with a resultant increase in the incidence of spatiotemporal structures that could facilitate sediment resuspension for the case of internal solitary waves we provide bounds in parameter space separating regions in which internal waves can be expected to efficiently resuspend sediment from those in which the boundary layer in the wave footprint is both laminar and stable a notable finding is that the onset of instability is a strong function of the background current the lagrangian transport of passive particles due to the instability is explored and some quantitative measures of the efficiency of the particle transport process are provided we subsequently discuss the evolution of the power spectra of the bottom shear stress with time and find that while the general characteristics of the instability are robust lowering either the reynolds number or the strength of the background current leads to an increase in the typical length scales associated with the mature instability finally we discuss instabilities during the internal wave generation process and alternative instability mechanisms when the bottom is not flat

initiation of a solitary wave family in the demise of a nocturnal thunderstorm density current abstract this paper describes the characteristics and evolving nature of a vigorous thunderstorm density current very early in the morning of 9 may 1981 in oklahoma because the ambient lower atmosphere was stratified interesting interactions between the outflow current and the ambient environment resulted the leading portion of the current was modulated by at least three gravity wavelike perturbations of horizontal spacing 12 km which initially coexisted with it however as the current evolved it initiated an undular borelike disturbance which propagated ahead into the stable boundary layer carrying cold outflow air in large amplitude rolls eventually the wave family left the decelerating outflow air in its wake this borelike disturbance resembles the australian morning glory phenomenon and appears to represent an early stage in the development of a solitary wave family the observations resemble other reported morning glories and solitary waves as well their laboratory and numerically simulated

comparative leaching experiments for trace elements in raw coal laboratory ash fly ash and bottom ash abstract samples of raw coal fly ash and bottom ash have been collected from a chinese power plant together with laboratory ash obtained by ashing of the coal under 850 c comparative leaching experiments were carried out on each fraction under various ph conditions a mathematical model for leaching of trace elements has been developed and leaching intensity il has been calculated for each element the results show that ph of the solution leaching time and particularly properties and occurrence of the elements have a strong influence on leaching behavior

mode 2 waves on the continental shelf ephemeral components of the nonlinear internal wavefield 1 shoreward propagating mode 2 nonlinear waves appear sporadically in mooring records obtained off the coast of new jersey in the summer of 2006 individual mode 2 packets were tracked between two moorings separated by 1 km however packets could not be tracked between moorings separated by greater distances from one another 10 km the inability to track individual packets large distances through the mooring array combined with detailed observations from a ship suggest that these waves are short lived the evolution of the ship tracked wave group was recorded using acoustic backscatter acoustic doppler current profilers and turbulence profiling the leading mode 2 wave quickly changed form and developed a tail of short small amplitude mode 1 waves the wavelength of the mode 1 oscillations agreed with that expected for a copropagating tail on the basis of linear theory turbulent dissipation in the mixed layer and radiation of the short mode 1 waves contributed to rapid energy loss in the leading mode 2 wave consistent with the observed decay rate and short life span of only a few hours the energy in the leading mode 2 wave was 10 100 times smaller than the energy of mode 1 nonlinear internal waves observed during the experiment however the magnitudes of wave localized turbulent dissipation were similar

electron microscope study of the reaction olivine h2o tio2 titanian clinohumite titanian chondrodite synthesized at 8 gpa 1300 k the nucleation and growth processes of titanian clinohumite ti cl and titanian chondrodite ti ch during hydrous alteration of olivine at 8 gpa 1300 k are described in detail we observed two different nucleation sites and orientation relationships for ti cl 1 heterogeneous nucleation at olivine grain or phase boundaries yielding semicoherent 001 lamellae with 001 ol 001 ti cl and 010 ol 010 ti cl 2 formation of coherent nanometer sized nuclei inside olivine with the orientation relationship 100 ol 001 ti cl and 011 ol 020 ti cl only the former for which the interface with olivine facilitates the transport of oh and ti necessary for the formation of the humite group minerals survives to large sizes these results suggest that ti cl should form readily in a ti and h rich environment at mantle temperatures independent of f content from shallow environments to those at depths exceeding 250 km and could play a role in recycling water back into the deep mantle

horizontal variability of high frequency nonlinear internal waves in massachusetts bay detected by an array of seafloor pressure sensors a two dimensional array of fourteen seafloor pressure sensors was deployed to measure properties of tidally generated nonlinear high frequency internal waves over a 14 km by 12 km area west of stellwagen bank in massachusetts bay during summer 2009 thirteen high frequency internal wave packets propagated through the region over 6 5 days one packet every semidiurnal cycle propagation speed and direction of wave packets were determined by triangulation using arrival times and distances between triads of sensor locations wavefront curvature ranged from straight to radially spreading with wave speeds generally faster to the south waves propagated to the southwest rotating to more westward with shoreward propagation linear theory predicts a relationship between kinetic energy and bottom pressure variance of internal waves that is sensitive to sheared background currents water depth and stratification by comparison to seafloor acoustic doppler current profiler measurements observations nonetheless show a strong relationship between kinetic energy and bottom pressure variance this is presumably due to phase locking of the wave packets to the internal tide that dominates background currents and to horizontally uniform and relatively constant stratification throughout the study this relationship was used to qualitatively describe variations in kinetic energy of the high frequency wave packets in general high frequency internal wave kinetic energy was greater near the southern extent of wavefronts and greatly decreased upon propagating shoreward of the 40 m isobath this article is protected by copyright all rights reserved

bottom pressure observations of deep sea internal hydrostatic and non hydrostatic motions in the ocean sloping bottom topography is important for the generation and dissipation of internal waves here the transition of such waves to turbulence is demonstrated using an accurate bottom pressure sensor that was moored with an acoustic doppler current profiler and high resolution thermistor string on the sloping side of the ocean guyot great meteor seamount water depth 549 m the site is dominated by the passage of strong frontal bores moving upslope once or twice every tidal period with a trail of high frequency internal waves the bore amplitude and precise timing of bore passage vary every tide a bore induces mainly non hydrostatic pressure while the trailing waves induce mainly internal hydrostatic pressure these separate internal wave pressure terms are independently estimated using current and temperature data respectively in the bottom pressure time series the passage of a bore is barely visible but the trailing high frequency internal waves are a bore is obscured by higher frequency pressure variations up to similar to 4 x 10 3 cpd approximate to 80n cpd cycles per day n the large scale buoyancy frequency these motions dominate the turbulent state of internal tides above a sloping bottom in contrast with previous bottom pressure observations in other areas infra gravity surface waves contribute little to these pressure variations in the same frequency range here such waves do not incur observed pressure this is verified in a consistency test for large reynolds number turbulence using high resolution temperature data the high frequency quasi turbulent internal motions are visible in detailed temperature and acoustic echo images revealing a nearly permanently wave turbulent tide going up and down the bottom slope over the entire observational period the spectral slope and variance of bottom pressure are equivalent to internal hydrostatic pressure due to internal waves in the lower 100 m above the bottom by non hydrostatic pressure due to high frequency internal waves and large scale overturning the observations suggest a transition between large scale internal waves small scale internal tidal waves residing on thin similar to 1 m stratified layers and turbulence

internal solitary waves control offshore extension of mud depocenters on the nw iberian shelf abstract hydrodynamic conditions and near bottom sediment transport on the nw iberian shelf associated with a 5 day storm in september 2014 were monitored during the post storm relaxation period active bottom sediment transport by internal solitary waves isws on a mid shelf mud depocenter located in between 110 and 130 m water depth wd was observed to explore the potential of internal waves in sediment transport and its link to development of mid shelf mud depocenters we apply a weakly nonlinear model based on the variable coefficient gardner equation to estimate the flow fields and bottom shear stress induced by shoaling of mode 1 long internal solitary waves shoreward propagation of the isws in three representative periods pre intra and post storm is simulated respectively transformation of the internal wave from a single sech2 shape characterized by negative polarity and small amplitude to a dispersive trailing wave packet with varying amplitude and inverse polarity are satisfactorily reproduced model results indicate enhancement of the maximum orbital velocity of the isws during and after the storm on the outer shelf 130 220 m wd including the seaward margin of the mud depocenter bottom shear stress consequently becomes strong enough 0 1 pa to winnow unconsolidated sediment and constrains the offshore extension of the depocenter the enhanced bottom orbital velocity and the asymmetry in the excursion direction of mode 1 long isws in the post storm period prove to be efficient in transporting fine grained sediment across shelf our results suggest that mid shelf mud depocenters are not necessarily areas under permanently calm conditions where fine grained sediment can settle straightforwardly they could also result from convergent sediment transport from both onshore and offshore directions and sediment may go through numerous cycles of resuspension transport deposition before its ultimate lasting burial

genesis of ilmenite rods and palisades along humite type defects in olivine from alpe arami rod shaped ilmenite inclusions in olivine have been observed in numerous peridotite lenses of the adula cima lunga unit central alps the rods are elongated parallel to 010 ol and identical in size shape and concentration to those reported from garnet peridotite at alpe arami aa tem investigation of the rods at aa cima di gagnone cdg and monte duria md demonstrates that the titanate inclusions correspond to a mg bearing ilmenite with exclusively a trigonal crystal structure no other fetio3 polymorphs have been identified the shape of the ilmenite inclusions concurs with minimum topotactic misfits between the lattices of olivine and mg bearing ilmenite optical microscopy reveals that the ilmenite rods are not randomly distributed within olivine but have at all localities a preferred alignment parallel to 001 ol forming palisades tem images of the ilmenite palisades at aa and cdg show that they are controlled by the presence of 001 planar defects in olivine along which the rods nucleated the defects have been characterised by high resolution tem and identified as 4 4 a wide humite type layers i e mg2sio4 mg oh f 2 intergrown within olivine in such layers substitution of up to 50 mol mgh2 by ti4 is possible assuming ti saturated humite slabs the maximum density of 001 faults observed at aa approximately 1900 mm 1 can accommodate about 170 ppm tio2 in olivine this represents about half the values obtained by uv laser ablation icp ms and empa analysis evidence for annealing of the defects however suggests that only parts of the defects are still preserved the formation of ilmenite rods is considered to be a consequence of the breakdown of isolated humite layers in olivine the apparent tio2 content in olivine at aa cdg and md is regarded as a function of the ti humite defect density

the effect of silica activity on the incorporation mechanisms of water in synthetic forsterite a polarised infrared spectroscopic study pure forsterite crystals were grown from hydrous melts using controlled cooling experiments at 2 0 gpa and varying the bulk mg si ratio from 2 0 to 1 5 oriented single crystals were then studied by polarised infrared spectroscopy the spectra of the samples with the lowest silica activity asio2 contain the main oh bands in the range 3 620 3 450 cm 1 only in contrast the spectra of the samples synthesised with the highest asio2 contain additional pleochroic bands at 3 160 3 220 and 3 600 cm 1 the variations are interpreted in terms of protonated silicon vacancies being dominant at low asio2 and mg vacancies dominant at high asio2 xenolithic mantle olivines generally do not have the spectrum expected for orthopyroxene buffered conditions suggesting that they re equilibrated with their host melts during ascent but mantle olivine from the zabargad peridotite massif probably is in equilibrium with the coexisting orthopyroxene

subduction of water into the mantle history of an alpine peridotite the erro tobbio peridotite western alps is a slice of subcontinental mantle that underwent pre jurassic passive rifting followed by sea floor hydration and cretaceous alpine subduction analysis of its extension and subduction related structures and metamorphism suggest the dip below the adria plate of both the extensional detachments and the subduction plane high pressure boudinage structures of rigid metarodingite within ductile antigorite serpentinite prove that antigorite survived subduction and remained stable at eclogite facies conditions subduction of serpentinized peridotites from ophiolite slabs is here considered the most effective mechanism of bringing water to great depth within the mantle

ftir spectroscopy of ti chondrodite ti clinohumite and olivine in deeply subducted serpentinites and implications for the deep water cycle separated olivine grains from a deeply subducted serpentinized wehrlite changawuzi in the western tianshan ultrahigh pressure belt china were analysed with unpolarized transmission ftir and the ti contents were determined using la icp ms the major bands in the olivine spectra display striking similarities to ti clinohumite and are interpreted as oh in lamellae the quantification of the water content in lamellae requires calibration of the ir absorption for such bands we have obtained a new absorption coefficient for ti clinohumite of 0 125 0 017 ppm cm2 based on polarized ftir measurements on three orthogonal sections through a large single crystal of ti clinohumite from val malenco which has a known water content of 1 53 wt the resulting water content in olivine using this calibration factor ranges from 440 to 2 600 ppm and correlates positively with the ti content that ranges from 130 to 1 400 ppm for the quantification of the water content in ti chondrodite and ti clinohumite that are associated with olivine we developed a new method using attenuated total reflectance ftir spectroscopy ti chondrodite and ti clinohumite display similar ir bands at 3 562 3 525 and 3 583 3 586 cm 1 as in olivine the water content and ti content correlate in both ti clinohumite and ti chondrodite indicating an intergrowth of these minerals which has been confirmed by tem analyses our results confirm previous suggestions that there is a strong correlation between the ti content of ultramafic rocks and their capacity to transport water to the deeper mantle in subduction zones beyond conditions where hydrous phases are stable

breakdown mechanisms of titanclinohumite in antigorite serpentinite cerro del almirez massif s spain a petrological and tem study abstract veins with titanclinohumite ti chu and olivine occur close to clinopyroxenite layers scattered through the antigorite serpentinites from the cerro del almirez ultramafic massif sierra nevada betic cordillera s spain they formed at estimated maximum p t conditions of 1 3 gpa and 475 c due to simultaneous breakdown of former ti rich clinopyroxene and brucite in the presence of 6 vol of free water breakdown of ti chu single crystals to an olivine ilmenite framework was gradual small relict patches of ti chu appear even at some distance from the reaction front and ilmenite grains coarsen and become less frequent away from the front detailed tem data support this interpretation olivine in equilibrium with ti chu is structurally and chemically homogeneous whereas ti chu shows ubiquitous intermixed 001 olivine lamellae product olivine close to the front shows pervasive and continuous 001 ti chu lamellar faults these become less frequent away from the reaction front due to the completion of the ti chu breakdown this textural sequence suggests both progressive transfer of ti to ilmenite and progressive release of h 2 o during the breakdown of ti chu a second hydration breakdown reaction can be observed very locally in the contact between ti chu and diopside producing a symplectitic intergrowth of tremolite and ilmenite textural features of both reactions point to a very limited availability of water during ti chu breakdown this suggests that veins operated as closed systems complete obliteration of ti chu owing to the antigorite dehydration breakdown can be observed in the almirez massif rocks this precludes oh ti chu from atg serpentinite as an efficient water or titanium carrier into deep mantle in hot subduction zones

near bed solibores over the continental slope in the faeroe shetland channel abstract on two occasions within a 12 day measurement period in the faeroe shetland channel strongly nonlinear wave trains were observed at the sea bed propagating up the continental slope in water depths 450 m the events were separated by a period of 4 days and whilst resembling in appearance a density current running up a slope are termed solibores displaying the properties of both turbulent internal bores and nonlinear internal solitary waves isw each solibore displays a steep leading edge followed by a train of nonlinear waves with amplitudes of o 10 m and periods of 5 20 min wave induced particle velocities are consistent with isw whilst a zone of strong horizontal convergence at the leading edge of the solibores causes the formation of a rotor with flow in the opposite sense to a forward overturning surface wave in both cases upward vertical velocities 10 cm s 1 are immediately followed by a return downward flow of equal magnitude a ctd and microstructure transect conducted during the passage of the first solibore illustrates its behaviour as an up slope intrusion of cold dense water with concurrent rates of turbulent dissipation e of o 10 7 w kg 1 and resulting in short term maximum vertical diffusivities kz of o 10 1 m2 s 1 in the long term however kz 140 days which again indicate intermittency in periods of enhanced sediment flux the solibores are consistent with the results of numerical and laboratory experiments on hydraulic jumps resulting from shoaling isw the influence of the slope is proposed to be the reason for their slightly different forms and effects on sediment transport thus the first solibore propagating directly up the slope is proposed to result from an overturning hydraulic jump caused by kinematic instabilities and which subsequently forms a horizontal density intrusion the second solibore represents a dispersive wave train due its oblique direction of propagation which reduces the effective bottom slope allowing dispersion to balance nonlinear effects and prohibiting overturning

measurement of tidal form drag using seafloor pressure sensors abstractas currents flow over rough topography the pressure difference between the up and downstream sides results in form drag a force that opposes the flow measuring form drag is valuable because it can be used to estimate the loss of energy from currents as they interact with topography an array of bottom pressure sensors was used to measure the tidal form drag on a sloping ridge in 200 m of water that forms a 1 km headland at the surface in puget sound washington the form drag per unit length of the ridge reached 1 104 n m 1 during peak flood tides the tidally averaged power removed from the tidal currents by form drag was 0 2 w m 2 which is 30 times larger than power losses to friction form drag is best parameterized by a linear wave drag law as opposed to a bluff body drag law because the flow is stratified and both internal waves and eddies are generated on the sloping topography maximum turbulent kinetic energy dissipation rates of 5 10 5 w kg 1 were measured with a microstructure pr

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

thermal equation of state of natural ti bearing clinohumite the natural occurrence of clinohumite in metabasalts and hydrothermally altered peridotites provides a source of water rich minerals in subducted slabs making knowledge of their phase relations and crystal chemistry under high p t conditions important for understating volatile recycling and geodynamic process in the earth s mantle here we present a synchrotron based single crystal x ray diffraction study on two natural ti bearing clinohumites up to 28 gpa and 750 k in order to simulate conditions within subducted slabs no phase transition occurs in clinohumite over this p t range pressure volume relationships of both compositions at room temperature were fitted to a third order birch murnaghan equation of state eos with v0 650 4 3 a3 kt0 141 4 gpa and kt0 4 0 6 for ti poor clinohumite 0 07 ti per formula unit pfu and v0 650 8 3 a3 kt0 144 4 gpa and kt0 3 6 7 for ti rich clinohumite 0 21 ti pfu both clinohumites exhibit anisotropic compression with b c a we also refined p v t equation of state parameters using the high temperature birch murnaghan htbm eos yielding kt0 t p 0 040 10 gpa k and t 5 1 6 10 5 k 1 for ti poor clinohumite kt0 t p 0 045 11 gpa k and t 5 7 6 10 5 k 1 for ti rich clinohumite ti poor and ti rich clinohumites display similar equations of state but are 20 more incompressible than mg pure clinohumite and display 5 higher bulk sound velocity than olivine at upper mantle conditions our results provide constraints for modeling geodynamic process related to the subduction and transport of potentially water rich slabs in the mantle

the infrared signature of water associated with trivalent cations in olivine abstract forsterite crystals were synthesised under water saturated conditions at 1400 c and 1 5 gpa doped with trace amounts of either b al sc ti v cr mn fe co ga y zr in sm gd dy tm or lu the common and intense hydroxyl stretching bands in the infrared spectra of spinel peridotite olivine at 3572 and 3525 cm 1 were only reproduced in the presence of ti those samples where the trace element substitutes as the trivalent cation on the mg 2 site were identified from a systematic variation in concentration with the trivalent ionic radius the hydroxyl region of all samples is essentially identical except for between 3300 and 3400 cm 1 this region is characterised by one or more bands with the energy of the most intense feature being correlated with the ionic radius of the trivalent cation the integrated intensity of these hydroxyl bands also correlates with the concentration of the trivalent cation these correlations provide unambiguous evidence that bands or peaks in this region correspond to water at defect sites associated with trivalent cations trivalent peaks are sometimes observed in samples of mantle olivine and most likely indicate water associated with fe 3 the water at this site is not incorporated under normal mantle conditions and should not be included in estimates of the water capacity of mantle olivine these results emphasise the importance of identifying the infrared signature of different water substitution mechanisms

mobilisation of elements from coal due to batch reactor experiments with co2 and water at 40 c and 9 5mpa injection of co2 into coal seams with or without enhanced coal bed methane recovery co2 ecbm is one method for sequestering co2 greenhouse gas emissions in the subsurface conventional saline formations that could be used for co2 sequestration also may have coal seams within the seal rock units however relatively little is known concerning the potential interactions between co2 acidified water and coal this geochemical study investigates the short term mobilisation of elements from selected samples of coal exposed to highly reactive conditions expected in the mixing front between the injected co2 plume and groundwater coals were obtained from both the permian bowen basin of queensland australia and the carboniferous ruhr basin of germany within a custom built batch reactor cubes of coal were reacted with supercritical co2 saturated water at 9 5mpa and 40 degrees celsius for 72h carbonate minerals within the coal cleats and matrix were most affected by the co2 water experiments as indicated by both sem images and reaction water chemistry an experiment with n2 saturated water to compare water only mobilisation with co2 water mobilisation was also done for a single sample in each of the seven sets of coals the effluent concentrations of several elements including al ba ca fe mg and mn consistently were greater during the co2 water coal experiments in comparison to water only mobilisation from the same samples whereas elements such as ag b hg k li na and sb were much less likely to be preferentially mobilised by co2 acidified water

solitary waves in the lower atmosphere solitary waves are of intense interest in the physical and mathematical sciences1 these nonlinear waves often seem to have a primary role in the asymptotic description of propagating disturbances in inland lakes and coastal waters2 4 in the thermocline of the open sea5 and in the lower atmosphere6 7 we present here new acoustic sounder observations of complex tropospheric solitary wave disturbances at tennant creek in the arid interior of australia fig 1 a description and interpretation of a new type of visible wave phenomena over northern australia which appear as thin propagating cumulus cloud lines and a discussion of observations at burketown on the gulf of carpentaria of a new class of low altitude propagating solitary wave roll clouds which originate to the south these observations when correlated with observations at tennant creek indicate that solitary wave generating disturbances in the form of internal bores8 9 propagate over large distances

the sulu sea internal soliton experiment abstract we present the results of a comprehensive study of large amplitude internal solitons generated in the sulu sea in the philippines by intense tidal flow over a sharp bathymetric feature surface signatures of these waves have been observed in images from the dmsp landsat and nimbus 7 satellites and the space shuttle sir a synthetic aperture radar a two week experiment was conducted in the sulu sea in may 1980 from r v oceanograher during which a three mooring phased array of current meters and thermistors was implanted near the wave source and at 82 km and 200 km from the source seventeen soliton packets were observed whose properties underwent significant change as they propagated across the sea vertical profiles of density temperature and acoustic backscatter as well as radar and photographic surface signatures were obtained from the ship data from satellites moorings and the ship give unprecedented information on the spatial and temporal characteristics of solitary waves which ha

the formation of internal bores in the atmosphere a laboratory model summary recently several atmospheric observations have been interpreted as internal undular bores or internal solitary waves evolving from internal bores that propagate along low level temperature inversions it has been speculated that such disturbances are generated by some type of gravity current such as cold fronts sea breeze fronts and thunderstorm outflows interacting with an existing temperature inversion in this paper we describe a systematic laboratory study in a water channel of internal bores and their generation by the movement of gravity currents through a two layer model of the atmosphere we compare the results of our laboratory experiments with previous theories and numerical simulations and with several detailed atmospheric observations of internal bores at different stages of development

a fresh approach to investigating co2 storage experimental co2 water rock interactions in a low salinity reservoir system the interactions between co2 water and rock in low salinity host formations remain largely unexplored for conditions relevant to co2 injection and storage core samples and sub plugs from five jurassic aged surat basin sandstones and siltstones of varying mineralogy have been experimentally reacted in low salinity water with supercritical co2 at simulated in situ reservoir conditions p 12mpa and t 60 c for 16days 384h with a view to characterising potential co2 water rock interactions in fresh or low salinity potential siliclastic co2 storage targets located in queensland australia co2 water rock reactions were coupled with detailed mineral and porosity characterisation obtained prior to and following reaction to identify changes in the mineralogy and porosity of selected reservoir and seal rocks during simulated co2 injection aqueous element concentrations were measured from fluid extracts obtained periodically throughout the experiments to infer fluid rock reactions over time fluid analyses show an evolution of dissolved concentration over time with most major e g ca fe si mg mn and minor e g s sr ba zn components increasing in concentration during reaction with co2 similar trends between elements reflect shared sources and or similar release mechanisms such as dissolution and desorption with decreasing ph small decreases in concentration of selected elements were observed towards the end of some experiments however no precipitation of minerals was directly observed in petrography sample characterisation on a fine scale allowed direct scrutiny of mineralogical and porosity changes by comparing pre and post reaction observations scanning electron microscopy and registered 3d images from micro computed tomography micro ct indicate dissolution of minerals including carbonates chlorite biotite members and to a lesser extent feldspars quantitative mineral mapping of sub plugs identified dissolution of calcite from carbonate cemented core with a decrease in calcite content from 17vol to 15vol following reaction and a subsequent increase in porosity of 1 1vol kinetic geochemical modelling of the co2 water rock experiments successfully reproduced the general trends observed in aqueous geochemistry for the investigated major elements after coupling experimental geochemistry with detailed sample characterisation and numerical modelling expected initial reactions in the near well region include partial dissolution and desorption of calcite mixed carbonates chloritic clays and annite due to ph decrease followed in the longer term by dissolution of additional silicates such as feldspars dissolution of carbonates is predicted to improve injectivity in the near well environment and contribute to the eventual re precipitation of carbonates in the far field