global observation of traveling atmospheric disturbances tads in the thermosphere 1 densities derived from accelerometer measurements on the champ satellite near 400 km are used to elucidate global scale characteristics of traveling atmospheric disturbances tads in connection with 3 sudden injections of energy at high latitudes on 29 may 2003 dayside tads with typical amplitudes 20 30 propagate towards the equator from the northern hemisphere southern hemisphere auroral region with phase speeds of order 730 ms 1 460 ms 1 some evidence is found for tad penetration from the northern to the southern hemisphere and for the first time for trans polar propagation nighttime tad signatures are less well defined but have phase speeds similar to the dayside tads the above day night and hemisphere differences possibly reflect dependencies on direction and intensity of the prevailing solar driven circulation and on generation efficiency and ion drag dissipation with respect to solar zenith angle

rare earth elements as tracers of sediment contamination by phosphogypsum in the santos estuary southern brazil in the cubatao region southern brazil sediments are transported by several rivers from the serra do mar ridge into the santos estuary fertilizer plants have been operating along the margins of one of these rivers mogi river producing a large volume of phosphogypsum which is stockpiled in nearby areas surface sediments of the mogi river were sampled upstream and downstream in relation to the point where the effluents of the phosphogypsum piles flow into the drainage system in the vicinity of this point one sediment core was collected results show that ree ba zr and th concentrations in the non contaminated sediments are of the same order as those present in the upper continental crust the contaminated samples present a composition affected by that of the phosphogypsum marked by a higher concentration of these elements and a stronger degree of ree fractionation these phosphogypsum characteristics are inherited from the catalao igneous phosphate ore and were moderately modified by the industrial process of phosphoric acid production the phosphogypsum signal decreases rapidly downstream pointing to a limited area of influence of the stacks the deepest sediments of the core are also free of contamination representing a time interval prior to the deposition of phosphogypsum wastes on the banks of the estuary

petrologic variations in quaternary volcanic rocks british columbia and the nature of the underlying upper mantle volcanic activity has produced late tertiary and quaternary cinder cones and flows between the snake river plain u s a and the yukon territory canada the rock types include basanites alkali olivine basalts high iron basalts hawaiites ankaramites nephelinites and olivine tholeiites the alkali olivine basalts basanites and hawaiites sampled are chemically similar to rocks from the mid atlantic islands associated with the volcanic rocks are xenoliths of ultramafic rocks gabbros granites and granulites

a case study of the ionospheric storm dusk effect the initial ionospheric storm positive phase often appears as a large enhancement in f region electron density at middle latitudes in the evening hours following a storm sudden commencement the cause of this dusk effect is still not well understood though several mechanisms have been proposed this phenomenon is studied using incoherent scatter radar data collected at millstone hill and total electron content data from a north south chain of stations during the may 26 27 1990 storm nine position millstone hill radar data allows estimation of gradients in electron density and in velocity components above the station from these the motion term in the continuity equation is calculated and used along with wind electric field data and modeling to assess the relative importance of the proposed mechanisms during this storm it is shown that a combination of mechanisms appear to have been involved including a traveling atmospheric disturbance advection of high density plasma from lower latitudes and neutral composition changes

chemical evolution of rare earth elements fractionation between colloidal and solution phases of filtered river water abstract within the dissolved fraction of connecticut river water there is large scale fractionation of rare earth elements between colloidal and solution phases colloidal particles carry a large part of the dissolved ree pool filtration through filters with progressively smaller pore size 0 45 0 22 and 0 025 m results in filtrates with lower absolute concentrations of ree and more fractionated compositions with decreasing pore size the filtrates have shale normalized abundances which become systematically more depleted in the lree relative to the hree hence both the solution and colloidal phases are significantly fractionated with respect to the dissolved fraction these conclusions are consistent with previous studies of ree in rivers estuaries and soils and with surface solution speciation models colloids play an important role in the aquatic geochemistry of rare earth elements they are responsible for the fractionation of ree during the estuarine removal of ree the removal of suspended and colloidal particles from river water leaves the solution phase of river water with compositions of ree as evolved as those of surface seawater hence the evolution of the composition of ree in river water and seawater is significantly influenced by colloid formation during chemical weathering on the continents

distribution of rare earth elements thorium and uranium in gulf of thailand s sediments distribution of rare earth elements rees thorium and uranium in 54 marine sediments collected from five selected areas along the gulf of thailand is discussed in this paper these areas have been selected as potential sites to set up thermal and nuclear power plants concentration of elements was determined using inductively coupled plasma mass spectrometry icp ms absolute concentrations of rees th and u show a sample to sample variation and may be due to different geological characteristic of area as well as grain size effect total ree concentrations not including y range between 9 4 and 206 g g the chondrite normalized ree patterns of all samples are similar to post archean australian shale paas and average upper continental crust with lrees enrichment relative to hrees lan ybn 6 5 29 fairly flat hrees patterns gdn ybn 1 0 3 8 and ubiquitous negative eu anomaly eu eu 0 3 0 7 th concentrations 0 9 28 g g are relatively higher than those of uranium 0 4 4 0 g g th u ratios 1 5 9 9 are higher than the average upper crust these results are consistent with terrigenous sediments that formed from the weathering and erosion of felsic rocks

multi instrument observations of sed during 24 25 october 2011 storm implications for sed formation processes 1 we present multiple instrument observations of a storm enhanced density sed during the 24 25 october 2011 intense geomagnetic storm formation and the subsequent evolution of the sed and the midlatitude trough are revealed by global gps vertical total electron content maps in addition we present high time resolution poker flat incoherent scatter radar pfisr observations of ionospheric profiles within the sed we divided the sed observed by pfisr into two parts both parts are characterized by elevated ionospheric peak height hmf2 and total electron content compared to quiet time values however the two parts of the sed have different characteristics in the electron temperature te the f region peak density nmf2 and convection flows the first part of the sed is associated with enhanced te in the lower f region and reduced te in the upper f region and is collocated with northward convection flows the nmf2 was lower than quiet time values the second part of the sed is associated with significantly increased nmf2 elevated te at all altitudes and is located near the equatorward boundary of large northwestward flows based on these observations we suggest that the mechanisms responsible for the formation of the two parts of the sed may be different the first part is due to equatorward expansion of the convection pattern and the projection of northward convection flows in the vertical direction which lifts the ionospheric plasma to higher altitudes and thus reduces the loss rate of plasma recombination the second part is more complicated besides equatorward expansion of the convection pattern and large upward flows evidences of other mechanisms including horizontal advection due to fast flows energetic particle precipitation and enhanced thermospheric wind in the topside ionosphere are also present estimates show that contribution from precipitating energetic protons is at most 10 of the total f region density the thermospheric wind also plays a minor role in this case

equatorial anomaly in ionospheric electron content and its relation to dynamo currents using the ats 6 satellite radio beacon data collected over a chain of stations in the indian zone a study has been made of the equatorial anomaly in total electron content tec and its relation to the e region currents two parameters hd the difference in the magnetic field perturbation between the equator and a low latitude station and vd the backscatter radar measurement of the draft velocity of the electrojet irregularities are used to represent the equatorial current strength the results presented in the form of regression plots relating the strength of the anomaly and that of the current indicate that the anomaly dependence on the current strength is about the same for all the three seasons it is also noted that regardless of the season the anomaly crest moves toward a farther latitude from the equator with increasing current strength the total ionization inventory tec of the anomaly belt is found to increase linearly with the strength of the equatorial current and this result seems to bear some significance for the correlation observed between tecmax and hdmax at the equator

dayside midlatitude ionospheric response to storm time electric fields a case study for 7 september 2002 1 with the storm of 7 8 september 2002 as a study case we demonstrate that an ionospheric model driven by a suitable storm time convection electric field can reproduce the f region dayside density enhancements associated with the ionospheric storm positive phase the ionospheric model in this case is the utah state university time dependent ionospheric model tdim the electric field model is the university of michigan s hot electron and ion drift integrator heidi extensive ground truth is available throughout the study period from two independent sources ground based vertical tec and ionosonde stations our simulation results are in good agreement with these observations we address the question of what is the source of the high density plasma that is seen during the positive storm phase and show that in this case a magnetospheric electric field with an eastward component that penetrates to midlatitudes increases local production on the dayside to a degree that is sufficient to account for the storm time density increases that have been observed

rare earth element fractionation by selective sediment dispersal in surface sediments the skagerrak abstract neutron activation analysis was carried out to study the abundance distribution and fractionation of ree rare earth elements in surface sediment samples of 28 box cores collected along transects across the skagerrak results show that the clays have 3 5 times higher contents of k sc cr fe co rb k cs ta and th lree la and ce and mree sm eu and tb compared to sands and silts the hree yb and lu are only up to two times enriched in the clays and silts compared with the values measured in sands shale normalized ree patterns vary from flat for the sands towards enrichment 1 3 1 5 times of lree relative to hree in the clays this is consistent with published ree data for oceanic and riverine sediments and evidences fractionation hf and zr are up to thee times enriched in sands and silts compared to clays samples with highest contents of hf show hree enrichment in shale normalized ree patterns simple model calculations show that on the average zircon grains in skagerrak silts and sands contain 800 1200 ppm yb assuming that this value is also valid for the zircon grains in the shales this indicates that lower hree contents observed in atlantic ocean shelf and oceanic sediments compared to shales cannot be related to a greater abundance of zircon in shales

multiradar observations of the polar tongue of ionization 1 we present a global view of large scale ionospheric disturbances during the main phase of a major geomagnetic storm we find that the low latitude auroral and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system for the large geomagnetic storm on 20 november 2003 we examine data from the high latitude incoherent scatter radars at millstone hill sondrestrom and eiscat tromso with superdarn hf radar observations of the high latitude convection pattern and dmsp observations of in situ plasma parameters in the topside ionosphere we combine these with north polar maps of stormtime plumes of enhanced total electron content tec derived from a network of gps receivers the polar tongue of ionization toi is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern the dayside source of the toi is the plume of storm enhanced density sed transported from low latitudes in the postnoon sector by the subauroral disturbance electric field convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral f region is significantly enhanced by the sed material the three incoherent scatter radars provided full altitude profiles of plasma density temperatures and vertical velocity as the toi plume crossed their different positions under the cusp in the center of the polar cap and at the midnight oval polar cap boundary greatly elevated f peak density 1 5e12 m 3 and low electron and ion temperatures 2500 k at the f peak altitude characterize the sed toi plasma observed at all points along its high latitude trajectory for this event sed toi f region tec 150 1000 km was 50 tecu both in the cusp and in the center of the polar cap large upward directed fluxes of o 1 e14 m 2 s 1 were observed in the topside ionosphere

amphibole in a spinel lherzolite xenolith evidence for volatiles and partial melting in the upper mantle beneath southern british columbia pargasitic amphibole has been observed for the first time in an ultramafic xenolith from british columbia the xenolith is a chrome diopside bearing spinel lherzolite trapped within an alkali basaltic lava flow at lightning peak near vernon british columbia amphibole 5 occurs within the xenolith as small grains interstitial between other xenolith mineral phases and always shows evidence of melting microprobe analyses of the amphibole reveal that it is a pargasite rich in mgo mgo 17 1 17 7 wt mg mg fe2 0 89 and cao 10 4 10 7 wt textural and chemical evidence suggests that the pargasite is in equilibrium with the other phases in spinel lherzolite the pargasite probably crystallized within the spinel stability field of the upper mantle from a volatile rich metasomatic fluid that was produced by dehydration of subducted material melting in the amphibole may have been caused by one of three processes superheating by the host alkali basalt decompression as the magma ascended or

on the generation decay of the storm enhanced density plumes role of the convection flow and field aligned ion flow storm enhanced density sed plumes are prominent ionospheric electron density increases at the dayside middle and high latitudes the generation and decay mechanisms of the plumes are still not clear we present observations of sed plumes during six storms between 2010 and 2013 and comprehensively analyze the associated ionospheric parameters within the plumes including vertical ion flow field aligned ion flow and flux plasma temperature and field aligned currents obtained from multiple instruments including gps total electron content tec poker flat incoherent scatter radar pfisr super dual auroral radar network and active magnetosphere and planetary electrodynamics response experiment the tec increase within the sed plumes at the pfisr site can be 1 4 5 5 times their quiet time value the plumes are usually associated with northwestward e b flows ranging from a couple of hundred m s 1 to 1 km s 1 upward vertical flows due to the projection of these e b drifts are mainly responsible for lifting the plasma in sunlit regions to higher altitude and thus leading to plume density enhancement the upward vertical flows near the poleward part of the plumes are more persistent while those near the equatorward part are more patchy in addition the plumes can be collocated with either upward or downward field aligned currents facs but are usually observed equatorward of the peak of the region 1 upward fac suggesting that the northwestward flows collocated with plumes can be either subauroral or auroral flows furthermore during the decay phase of the plume large downward ion flows as large as 200 m s 1 and downward fluxes as large as 1014 m 2 s 1 are often observed within the plumes in our study of six storms enhanced ambipolar diffusion due to an elevated pressure gradient is able to explain two of the four large downward flow flux cases but this mechanism is not sufficient for the other two cases where the flows are of larger magnitude for the latter two cases enhanced poleward thermospheric wind is suggested to be another mechanism for pushing the plasma downward along the field line these downward flows should be an important mechanism for the decay of the sed plumes

ionospheric electron content within the equatorial f 2 layer anomaly belt this paper describes some new results on the day to day behavior of the location of the equatorial anomaly in the columnar electron content the measurements were made from a unique network of stations covering dip latitudes from 0 n to 25 n during the period in 1975 1976 near sunspot minimum when the ats 6 satellite was visible from india the latitudinal distribution of the total electron content on a particular day was found to depend only on the strength of the electrojet current as determined by the difference of the horizontal magnetic field at stations on the magnetic equator and another outside the equatorial electrojet rather than on the horizontal magnetic field measured only at the equatorial station during magnetically disturbed periods the presence or absence of the anomaly was also found to depend only upon the strength of the electrojet current the varying electrojet current that is the equatorial electric field is very effective in moving the ionization to the anomaly latitudes of 15 20 but the columnar electron content over the magnetic equator remains relatively constant

relative importance of horizontal and vertical transports to the formation of ionospheric storm enhanced density and polar tongue of ionization there are still uncertainties regarding the formation mechanisms for storm enhanced density sed in the high and subauroral latitude ionosphere in this work we deploy the thermosphere ionosphere electrodynamic general circulation model tiegcm and gps total electron content tec observations to identify the principle mechanisms for sed and the tongue of ionization toi through term by term analysis of the ion continuity equation and also identify the advantages and deficiencies of the tiegcm in capturing high latitude and subauroral latitude ionospheric fine structures for the two geomagnetic storm events occurring on 17 march 2013 and 2015 our results show that in the topside ionosphere upward e b ion drifts are most important in sed formation and are offset by antisunward neutral winds and downward ambipolar diffusion effects in the bottomside f region ionosphere neutral winds play a major role in generating seds sed signature in tec is mainly caused by upward e b ion drifts that lift the ionosphere to higher altitudes where chemical recombination is slower horizontal e b ion drifts play an essential role in transporting plasma from the dayside convection throat region to the polar cap to form tois inconsistencies between model results and gps tec data were found 1 gps relative tec difference between storm time and quiet time has holes in the dayside ion convection entrance region which do not appear in the model results 2 the model tends to overestimate electron density enhancements in the polar region possible causes for these inconsistencies are discussed in this article

alkaline rocks from continental brazil abstract the present literature review on brazilian alkaline rocks stresses mainly the petrographic and geologic aspects at least eight different rock associations are represented agewise four groups are found among southern brazilian outcrops an older one about 240 m y only that is still poorly known the massifs clustered around jacupiranga about 130 m y old a few occurrences 100 110 m y old tunas itapirapua and the youngest and most important one with an age spread from about 80 m y to about 53 m y recent research shows a clear tectonic control both on local and on regional scales of alkaline occurrences in southern brazil alkaline magmatism was set off by pre drift and drift activity and is at its onset geologically related to basaltic activity emplacement of many massifs is also locally controlled by old lineaments e g in the minas gerais goias belt as is emphasized by geophysical data on a petrographic and chronologic basis several alkaline provinces are distinguished in southern brazil preliminary data on the cambrian precambrian rocks from southern bahia state a province with undersaturated syenites and litchfieldites and from cratonic areas in northern brazil are also presented

direct observations of the role of convection electric field in the formation of a polar tongue of ionization from storm enhanced density 1 we examine the relationship of convection electric fields to the formation of a polar cap tongue of ionization toi from midlatitude plumes of storm enhanced density sed observations from the geomagnetic storm on 26 27 september 2011 are presented for two distinct sed events during an hour long period of geomagnetic activity driven by a coronal mass ejection a channel of high density f region plasma was transported from the dayside subauroral ionosphere and into the polar cap by enhanced convection electric fields extending to middle latitudes this toi feature was associated with enhanced hf backscatter indicating that it was the seat of active formation of small scale irregularities after the solar wind interplanetary magnetic field conditions quieted and the dayside convection electric fields retreated to higher latitudes an sed plume was observed extending to but not entering the dayside cusp region this prominent feature in the distribution of total electron content tec persisted for several hours and elongated in magnetic local time with the rotation of the earth no ionospheric scatter from superdarn radars was observed within this sed region the source mechanism enhanced electric fields previously drawing the plasma from midlatitudes and into the polar cap as a toi was no longer active resulting in a fossil feature we thus demonstrate the controlling role exercised by the convection electric field in generating a toi from midlatitude sed

another look at rare earth elements in shales linear correlation and mass balance considerations indicate that clays are more important than zircon or other heavy minerals in hosting both light and heavy ree in cratonic shales considering the uniformity of the eu anomaly and ree distributions in cratonic shales it seems likely that detritus is thoroughly mixed during weathering and sediment transport and that the ree patterns in shales reflect the average ree pattern of the sources regardless of the ratio of clays to heavy minerals in the shales shales suspended river loads and near shore marine sediments all have broadly similar ree patterns and reported hree depletions in the latter two groups may reflect incomplete dissolution of heavy minerals during sample preparation ree distributions in shales and suspended river loads determined by inna are similar to those in average upper continent crust and ree distributions in shale averages nasc and paas seem to be reasonably representative of the average composition of post archean upper continental crust

altitude adjusted corrected geomagnetic coordinates definition and functional approximations analysis of the functional approximations used to transform between geo graphic and altitude adjusted corrected geomagnetic aacgm coordinates reveals that errors of 50 km can occur in the auroral and polar regions these errors are the result of efforts to better approximate aacgm coordinates near the magnetic equator and the south atlantic anomaly in these regions aacgm coordinates are not defined and alternate coordinates have been used this augmentation and emphasis on the so lution in regions near the equator result in spherical harmonic approximating functions that are less accurate than need be in the auroral and polar regions in response a new set of spherical harmonic coefficients have been derived that better represent aacgm coordinates in these regions these new aacgm coefficients are limited to below 2000 km in altitude in order to ensure accuracy for altitudes above 2000 km a magnetic field line tracing solution is recommended a software package developed to take advantage of the new aacgm coefficients provides the capability of tracing magnetic field lines at any altitude for improved accuracy in addition linear interpolation between 5 year epochs is used to produce coordinates that vary smoothly over the entire period from 1965 present the intent of this work is to provide a more accurate procedure for de termining aacgm coordinates in the auroral and polar regions for the study of mag netospheric and ionospheric processes

millstone hill incoherent scatter f region observations during the disturbances of june 1991 the extreme geomagnetic disturbances of early june 1991 were accompanied by dramatic effects in the earth s thermosphere and ionosphere which are the subject of coordinated analysis by the coupling energetics and dynamics of atmospheric regions cedar storm study project f region observations taken at millstone hill over the interval june 5 11 using a nine position experiment allow estimation of spatial gradients in ionospheric parameters above the station from these gradients the motion term in the f region continuity equation is obtained and combined with calculations of rates of production and loss of the major ions in a semiempirical model of the f region ionosphere above millstone hill electron densities calculated from this semiempirical model using msis 86 are generally much smaller than the measurements this discrepancy could be explained by the presence of vibrationally excited n sub 2 combined with a decrease in the atomic oxygen to molecular composition ratio of approx 2 or more on the most disturbed days neutral winds calculated by using the incoherent scatter line of sight ion drifts show a strong equatorward surge during the day on june 5 and strong equatorward surges during all the disturbed nights synoptic observations taken from millstone hill by using elevation and azimuth scans duringmore the nights of june 12 13 and 14 illustrate the large scale structure of electron density and its relation to neutral winds and electric fields observed over much of eastern north america 58 refs 12 figs 1 tab less

variations in the low and middle latitude topside ion concentration observed by dmsp during superstorm events 1 observations of the topside ion number density by the dmsp satellites on the dayside near 0930 lt and near dusk describe a characteristic evolution during the course of three superstorm events in november 2001 november 2003 and november 2004 density enhancements at middle latitudes and at the equator may be identified as separate features that may appear together but can evolve independently these characteristics are consistent with the action of both upward outward e b drifts and equatorward neutral winds and it is suggested that both f region drivers are required to reproduce the observed behavior on these occasions upward excursions of the e b drift at the equator may be short lived compared to the satellite orbit period of about 100 min but may also exist for longer periods under the influence of penetration fields and modified dynamo fields upward drifts at middle latitudes may be induced by meridional winds and by the high latitude convection pattern as it expands to latitudes as low as 40 degrees magnetic

geochemistry of rare earth elements in the mainstream of the yangtze river china abstract water suspended matter and sediment samples were taken from 8 locations along the yangtze river in 1992 the concentration and speciation exchangeable bound to carbonates bound to fe mn oxides bound to organic matter and residual forms of rare earth elements la ce nd sm eu tb yb and lu were determined by instrumental neutron activation analysis inaa the contents of the soluble fraction of rees in the river are low and rees mainly reside in particulate form in the particles the chondrite normalized distribution patterns show significant lree enrichment and eu depletion while normalized to shales both sediments and suspended matter samples show relative lree enrichment and hree depletion rees are relatively enriched in fine grained fractions of the sediments the speciation characteristics of rees in the sediments and suspended matter are very similar the amount of the five forms follows the order residual bound to organic matter bound to fe mn oxides bound to carbonates exchangeable about 65 to 85 of rees in the particles exist in the residual form and the exchangeable form is very low high proportions of residual rees reveal that rees in sediments and suspended matter are controlled by their abundances in the earth s crust carbonate fe mn oxide and organic fractions of rees in sediments account for 2 4 6 9 5 2 11 1 and 7 3 14 0 of the total contents respectively they are similar to those in the suspended matter this shows that carbonates fe mn oxides and organic matter play important roles during the particle water interaction processes by normalization to shales the 3 forms of rees follow convex shapes according to atomic number with middle ree sm eu and tb enrichment while light ree and heavy ree are depleted

a physical mechanism of positive ionospheric storms at low latitudes and midlatitudes 1 a physical mechanism of the positive ionospheric storms at low latitudes and midlatitudes is presented through multi instrument observations theoretical modeling and basic principles according to the mechanism an equatorward neutral wind is required to produce positive ionospheric storms the mechanical effects of the wind 1 reduce or stop the downward diffusion of plasma along the geomagnetic field lines 2 raise the ionosphere to high altitudes of reduced chemical loss and hence 3 accumulate the plasma at altitudes near and above the ionospheric peak centered at around 30 magnetic latitudes daytime eastward prompt penetration electric field ppef if it occurs also shifts the equatorial ionization anomaly crests to higher than normal latitudes up to approximately 30 latitudes the positive ionospheric storms are most likely in the longitudes where the onset of the geomagnetic storms falls in the ionization production dominated morning noon local time sector when the plasma accumulation due to the mechanical effects of the wind largely exceeds the plasma loss due to the chemical effect of the wind the mechanism agrees with the multi instrument observations made during the supergeomagnetic storm of 7 8 november 2004 with 18 h long initial phase ip and 10 h long main phase mp the observations which are mainly in the japanese australian longitudes where the mp onset was in the morning 0600 lt 2100 ut show 1 strong positive ionospheric storms in ne nmax hmax global positioning system total electron content gps tec and 630 nm airglow intensity in both northern and southern hemispheres started at the morning 0600 lt mp onset and lasted for a day 2 repeated occurrence of strong eastward ppef events penetrated after the mp onset and superposed with westward electric field started before the mp onset and 3 storm time equatorward neutral winds inferred from 1 and 2 repeated occurrence of an unusually strong f3 layer with large density depletions around the equator was also observed during the morning noon mp

ionospheric signatures of a plasmaspheric plume over europe 1 previously ionospheric signatures of plasmaspheric plumes were reported only at the north american longitude sector this led to the hypothesis that the geomagnetic field configuration at those longitudes played a vital role in the observation of plasmaspheric plume signatures only over the american continent combining ground based gps total electron content tec eiscat incoherent scattering radar isr and dmsp f15 ion drift meter observations we have observed greatly elevated density over the european continent during storm recovery phase on 12 september 2005 the tec seen over europe has a tongue of enhanced ionization extending to higher latitudes which is identical to the plasmaspheric plume signatures that have been often observed over north america therefore our observations clearly demonstrate that ionospheric signatures of plasmaspheric plumes are not limited to the north american sector and suggest that they may be observed at any longitude as long as a dense array of instruments are available to identify these signatures citation yizengaw e m b moldwin and d a galvan 2006 ionospheric signatures of a plasmaspheric plume over europe geophys res lett 33 l17103 doi 10 1029 2006gl026597

alteration of oceanic crust and geologic cycling of chlorine and water we report new estimates of transport rates for h2o and cl between the mantle and surface reservoirs our estimates take into consideration alteration of oceanic crust especially that of plutonic rocks and possible subduction of sediments the effect of hydrothermal alteration on the cl budget seems to be negligible but the effect on the h2o budget is significant altered oceanic crust excluding sediments contains about 10 times as much h2o as the unaltered crust and its subduction may result in a net transport of h2o to the upper mantle in subduction zones however the rate of expulsion of h2o from the mantle by subduction zone magmatism is comparable to the amount released by ridge magmatism and is only about 10 of the amount subducted therefore about 90 of the subducted h2o must be returned to the mantle or returned to the crust by other processes in addition subduction of oceanic sediments to mantle depths will result in 1 1 a further increase in the return rate of h2o to the mantle reservoir 2 2 possible net transfer of cl to the mantle depending on the rate of pore water expulsion

ionospheric response to the geomagnetic storm of 15 may 2005 over midlatitudes in the day and night sectors simultaneously the ionospheric response to the geomagnetic storm of 15 may 2005 has been studied over midlatitude stations in the dayside and nightside simultaneously in the day side the ionospheric response has been studied using the ground based gps and ionosonde measurements from the stations pol2 and alma ata respectively the dayside total electron content tec and fof2 variations are characterized by two well separated enhancements of which the first enhancement in both the parameters is attributed to the episode of prompt penetration electric field caused by the sudden southward turning of interplanetary magnetic field imf bz around 0600 ut the second enhancement which was also superposed by wave like modulations has been attributed to the storm induced winds the maximum peak to peak amplitude of modulation in tec is found to be 5 tecu total electron content unit 1 tecu 1016 el m 2 the enhanced plasma density observed during the daytime at midlatitudes is found to be locally produced and not transported from the equatorial ionization anomaly region because the time of enhanced plasma density at midlatitude is earlier than that observed at low latitudes during the storm main phase the nightside gps observations from the midlatitude station algo algonquin park canada show moderate to large tec fluctuations and short duration depletions that occur in a narrow latitude zone these fluctuations and depletions in tec have been attributed to the combined effect of storm induced equatorward movement of the midlatitude ionospheric trough due to the expansion of auroral oval and the storm time enhanced density the maximum amplitude of the tec depletions is found to be of the order of 20 tecu rate of tec index is also found to be high with a maximum value of 2

storm time plasma transport at middle and high latitudes associated with the large scale enhancement of the ionospheric convection electric field during disturbed geomagnetic conditions solar produced f region plasma is transported to and through the noontime cleft from a source region at middle and low latitudes in the afternoon sector as a result of the offset between the geomagnetic and geographic poles the afternoon sector region of strong sunward convection is shifted to increasingly lower geographic latitude throughout the interval between 12 ut and 24 ut a snowplow effect occurs in which the convection cell continually encounters fresh corotating ionospheric plasma along its equatorward edge producing a latitudinally narrow region of storm enhanced plasma density sed and increased total electron content which is advected toward higher latitudes in the noon sector the millstone hill incoherent scatter radar regularly observes sed as a spatially continuous large scale feature spanning local times between noon and midnight and at latitudes between the polar cap and its mid or low latitude source region for local times away from noon the latitude of most probable sed occurrence moves equatorward by 6 for an increase of 2 in the kp index during strong disturbances the topside sed is observed to be convecting sunward at 750 m s 1 with a flux of 1014 m 2 s 1 this feature accounts for the pronounced enhancement of ionospheric density near dusk at middle latitudes observed during the early stages of magnetic storms called the dusk effect and constitutes a source for the enhanced f region plasma observed in the polar cap during disturbed conditions

penetration of magnetospheric electric fields to the equator during a geomagnetic storm 1 penetration of the magnetospheric electric field to the equatorial ionosphere was examined for the geomagnetic storm on 6 november 2001 by analyzing the difference in magnitude of the geomagnetic storm recorded at the dayside geomagnetic equator yap 0 3 gml and low latitude okinawa 14 47 gml the penetrated electric field caused the dp2 currents at the equator i e eastward currents during the main phase of the storm while the overshielding currents i e westward currents dominated during the recovery phase it is shown that the ring current started to develop simultaneously with the onset of the equatorial dp2 within the temporal resolution of a few minutes these results imply prompt transmission of the dawn to dusk convection electric field to the inner magnetosphere as well as to the equatorial ionosphere it is found that the equatorial dp2 started to decrease one hour after the onset of the ring current development indicating shielding effects becoming effective at the equator during the latter half of the storm main phase the dp2 was then overwhelmed by the overshielding which resulted in the counter electrojet cej in the beginning of the storm recovery phase the image magnetometer chain data indicate that the westward auroral electrojet aej in the dawn sector was driven over midlatitude centered at 57 corrected geomagnetic latitude cgml during the main phase while the aej shifted rapidly poleward to the auroral latitude centered at 67 cgml in the beginning of the recovery phase the overshielding must be caused by the abrupt poleward shift of the rl facs as inferred from the poleward shift of the aej in addition to the decrease in their magnitude due to the decrease in magnitude of the southward imf the geomagnetic storm at the dayside geomagnetic equator was enhanced in amplitude with the ratio of 2 7 as compared with the geomagnetic storm at low latitude this amplification is a result of both effects of the dp2 currents and the cej associated with the main and recovery phases respectively it is suggested that the electric field associated with the dp2 currents contributed to the development of the ring current during the main phase while the overshielding electric field may contribute to cease developing the ring current during the recovery phase

storm induced plasma stream in the low latitude to midlatitude ionosphere 1 geomagnetic disturbances from 7 to 12 november 2004 were quite intense and the maximum excursion of dst reached 374 nt unusual ionospheric phenomena have been observed around the world that have been associated with successive magnetic storms during this period the ionospheric total electron content tec was increased at the longitudes of japan within a short time after sunset on 8 november from 20 tec units at 1830 jst to 97 tec units at 2015 jst jst ut 9 h where 1 tec unit 1 1016 el m2 the enhanced tec was significant over hokkaido 43 n and the center of the enhanced region was well within the plasmasphere as an l value of approximately 1 5 the drift velocity of the plasma in the density enhanced region measured by the defense meteorological satellite program dmsp satellite was westward with a peak value of 250 m s in the earth s frame demonstrating a positive correlation between density and drift velocity a similar tec event was observed after sunset on 10 november tec was enhanced from 15 tec units at 1830 jst to 45 tec units at 2030 jst during the second event the ionosphere was highly structured and the rate of the tec index roti increased the two dimensional map of a roti enhanced region exhibited the west to northwest transportation of plasma in which density irregularities were entrained a physical mechanism is proposed to explain these disturbances i e storm induced plasma stream which is different from a phenomenon called storm enhanced density at midlatitudes

ionospheric redistribution during geomagnetic storms 1 the abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms recent reports suggest that the magnitude of the plasma density enhancement depends on the ut of storm onset this possibility is investigated over a 7year period using global maps of ionospheric total electron content tec produced at the jet propulsion laboratory the analysis confirms that the american sector exhibits on average larger storm time enhancement in ionospheric plasma content up to 50 in the afternoon middle latitude region and 30 in the vicinity of the high latitude auroral cusp with largest effect in the southern hemisphere we investigate whether this effect is related to the magnitude of the causative magnetic storms using the same advanced dst index employed to sort the tec maps into quiet and active dst 100 nt sets we find variation in storm strength that corresponds closely to the tec variation but follows it by 3 6h for this and other reasons detailed in this report we conclude that the ut dependent peak in storm time tec is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the south american region the large dst variation suggests a possible system level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current possibly connected through ut dependent modulation of ion outflow

the development of middle rare earth element enrichments in freshwaters weathering of phosphate minerals abstract many phosphatic minerals of biogenic authigenic and diagenetic origin are distinguished by rare earth element ree compositions which have a well developed middle rare earth element mree enrichment defined by a gradual increase in the shale normalized ratios of ree toward the middle of the ree series la to lu also the ree composition of dissolved matter in the waters of the amazon fly and sepik rivers as well as other river lake and ground waters have well developed mree enrichments the development of mree enrichments was studied through a series of leaching experiments using river bank sediments from the amazon fly sepik and mississippi rivers a well characterized phosphate mineral rich shale with a pronounced mree enrichment in its bulk composition was also leached in order to better assess the relationship between the weathering of phosphate minerals and the formation of mree enriched solutions the two leaching solutions per sediment consisted of filtered lake water at ph 5 and the same water adjusted to ph 2 leaching experiments with the four river sediments result in extensive fractionation whereby the ree compositions of the solutions develop mree enrichments from starting sediments that show no mree enrichments the ph 2 leachates have much higher concentrations of the ree and more fully developed mree enrichments than do the ph 5 leachates the mree enrichments at ph 2 usually form within an hour of starting the experiments the phosphatic shale results show that there is preferential release of large amounts of mree at ph 5 as well as at ph 2 demonstrating the weather ability of the phosphatic minerals at phs of natural freshwaters the sepik river ph 5 experiment also shows significant mree enrichment under near neutral conditions the development and retention of the mree enrichments in the leaching solutions is accompanied by an increase in dissolved phosphate concentrations although the magnitudes of the mree enrichment do not directly correlate with the percent of phosphate released the experimental data suggest that the preferential dissolution of phosphatic minerals during weathering can result in extensive ree fractionation between bulk river sediment and water leading to freshwaters with mree enrichments

the rare earth element compositions of the changjiang yangtze and huanghe yellow river sediments thirty four samples from the changjiang and huanghe were analyzed to characterize their rare earth element ree compositions although ree concentrations in the changjiang sediments are higher than those of the huanghe sediments the former are less variable bulk samples and acid leachable fractions have convex ree patterns and middle ree enrichments relative to upper continental crust whereas flat patterns are present in the residual fractions source rock composition is the primary control on ree composition and weathering processes play a minor role grain size exerts some influence on ree composition as demonstrated by the higher ree contents of clay minerals in sediments from both rivers heavy minerals contribute about 10 20 of the total ree in the sediments apatite is rare in the river sediments and contributes less than 2 of the ree content but other heavy minerals such as sphene allanite and zircon are important reservoirs of residual ree fractions the fe mn oxides phase accounts for about 14 of bulk ree content in the changjiang sediments which could be one of the more important factors controlling ree fractionation in the leachable fraction 6 2002 elsevier science b v all rights reserved

extreme enhancement in total electron content after sunset on 8 november 2004 and its connection with storm enhanced density 1 after sunset on 8 november 2004 the ionospheric total electron content tec was observed to have anomalously increased following a severe daytime positive tec storm at longitudes of japan the observation was made using a dense gps receiver network and covered a geographic latitudinal range of 27 to 45 n there was a greater increase in tec at higher latitudes in the evening and the tec reached 90 tec units at 45 n 40 n magnetic latitude at 1145 ut 2045 lt the tec enhancement exhibited features significantly different from those of positive tec storms normally observed at japan s longitudes these features are interpreted as low latitude signatures of a storm enhanced density sed previously seds were reported only at longitudes of america and this led to the hypothesis that geomagnetic field configurations at these longitudes play a role in their formation the present observations indicate that seds can be observed at other longitudes

origin of rare earth element anomalies in mangrove sediments sepetiba bay se brazil used as geochemical tracers of sediment sources elemental contents were determined in two mangrove habitats along sepetiba bay se brazil an area impacted by local industrial activities as well as hinterland water diversion networks this study demonstrates how specific rees la ce nd sm eu tb yb and lu may be used as a sediment source tracer to mangrove dominated coastlines from the two stations studied a pair of cores was collected one in the mangrove forest and the other in the tidal flat station 1 results show a general enrichment in most of the fractioned patterns of the rees normalised by post archean australian shale the relatively light rare earth elements are similarly enriched in the generally more polluted station 1 despite the probable difference in background sediment characteristics a common sharp increase in mud contents patterns in the upper part of the mangrove sediment core was related to a lower ree content as well as eu anomalies with existing knowledge of clockwise water circulation in the bay these patterns can be explained by man made water diversion from the sao francisco and guandu rivers initiated more than 30 years ago whereby suspended matter with relatively large contents of rees and material originating from industrial sources accumulate in the eastern sector of the bay this is the first comprehensive assessment of rees as sedimentary tracers in a mangrove ecosystem in brazil