continental inputs of beryllium to the oceans abstract an understanding of the geochemistry of the cosmogenic radioisotope 10 be t 1 2 1 5 my and the stable isotope 9 be is necessary for the development of their use in deep sea sediments as a geochronometer and as a monitor of variations in cosmogenic nuclide production we examined these isotopes in oceanic regions strongly influenced by input of continental materials the effects of atmospheric aerosols were studied through examination of the water column chemistry of the mediterranean a basin strongly influenced by saharan dust while salinity transects through the amazon and ganges brahmaputra estuaries were used to investigate riverine fluxes to the oceans these results were used to quantify riverine and eolian fluxes they indicate that eolian dust is probably the most significant source of 9 be to the oceans changes in 10 be 9 be in the marine sedimentary record which are not associated with radioactive decay or variability in 10 be production can thus result from local or regional changes in dust inputs

global distribution of beryllium isotopes in deep ocean water as derived from femn crusts the direct measurement of the ratio of cosmogenic 10be t12 1 5 ma to stable terrigenously sourced 9be in deep seawater or marine deposits can be used to trace water mass movements and to quantify the incorporation of trace metals into the deep sea in this study a sims based technique has been used to determine the 10be9be ratios of the outermost millimetre of hydrogenetic ferromanganese crusts from the worlds oceans 10be9be ratios time corrected for radioactive decay of cosmogenic 10be using 234u238u are in good agreement with ams measurements of modern deep seawater ratios are relatively low in the north and equatorial atlantic samples 0 4 0 5 10 7 in the southwest atlantic ratios increase up to 1 10 7 they vary between 0 7 and 1 0 10 7 in indian ocean samples and have a near constant value of 1 1 0 2 10 7 for all pacific samples if the residence time of 10be 10be in deep water is constant globally then the observed variations in 10be9be ratios could be caused by accumulation of 10be in deep water as it flows and ages along the conveyor following a transient depletion upon its formation in the northern atlantic in this view both 10be and 9be reach local steady state concentration in pacific deep water and the global 10be 600 a an alternative possibility is that the be isotope abundances are controlled by local scavenging for this scenario 10be would vary according to local particle concentration and would 600 a in the central pacific but 10be 230 a in the atlantic mass balance considerations indicate that hydrothermal additions of 9be to the oceans are negligible and that the dissolved riverine source is also small furthermore aeolian dust input of 9be appears insufficient to provide the dissolved 9be inventory the dissolution of only a small proportion 2 of river derived particulates could in principle supply the observed seawater 9be content if true ocean margins would be the sites for 9be addition due to the particle reactive nature of be these would also be the primary sites of be removal a possible net result of horizontal water masses passing through these marginal areas might be a decrease in seawater 10be9be and establishment of a relatively constant 9be concentration as 10be 600 a is less than the apparent age of deep water in the pacific 1500 a the pacific record of 10be9be is not expected to show secular variations due to changes in deep water flow despite the large variations in 10be9be between different water masses because of this insensitivity to deep water flow however it is suggested that the 10be9be ratio determined in the authigenic phase of marine sediments or hydrogenetic precipitates should be a suitable tool for monitoring changes in continental input or cosmic ray intensity on longer time scales

rapid filamentation zones in intense tropical cyclones intense tropical cyclones often possess relatively little convection around their cores in radar composites this surrounding region is usually echo free or contains light stratiform precipitation while subsidence is typically quite pronounced in this region it is not the only mechanism suppressing convection another possible mechanism leading to weak echo moats is presented in this paper the basic idea is that the strain dominated flow surrounding an intense vortex core creates an unfavorable environment for sustained deep moist convection strain dominated regions of a tropical cyclone can be distinguished from rotationdominated regions by the sign of s 2 s 2 2 where s1 ux y and s2 x uy are the rates of strain and x uy is the relative vorticity within the radius of maximum tangential wind the flow tends to be rotation dominated 2 s 2 s 2 so that coherent structures such as mesovortices can survive for long periods of time outside the radius of maximum tangential wind the flow tends to be strain dominated s 2 s 2 2 resulting in filaments of anomalous vorticity in the regions of strain dominated flow the filamentation time is defined as fil 2 s 2 s 2 2 1 2 in a tropical cyclone an approximately 30 kmwide annular region can exist just outside the radius of maximum tangential wind where fil is less than 30 min and even as small as 5 min this region is defined as the rapid filamentation zone since the time scale for deep moist convective overturning is approximately 30 min deep convection can be significantly distorted and even suppressed in the rapid filamentation zone a nondivergent barotropic model illustrates the effects of rapid filamentation zones in category 1 5 hurricanes and demonstrates the evolution of such zones during binary vortex interaction and mesovortex formation from a thin annular ring of enhanced vorticity

changes in tourmaline composition during magmatic and hydrothermal processes leading to tin ore deposition the cornubian batholith sw england abstract to investigate the potential of tourmaline as a geochemical monitor a comprehensive dataset on major minor and trace element concentrations as well as fe3 fe ratios of tourmaline is presented the dataset includes samples from five plutonic complexes related to diverse magmatic to hydrothermal stages of the cornubian batholith sw england tourmaline composition found in barren and cassiterite bearing samples include all three primary tourmaline groups and tourmaline species with the general endmembers schorl dravite elbaite uvite feruvite foitite and mg foitite based on textures and compositions it is possible to distinguish not only between late magmatic and hydrothermal tourmaline but also between several formation stages hence tourmaline monitors late magmatic processes and the partitioning of elements during exsolution of an aqueous phase for example in hydrothermal tourmaline sn is strongly enriched while ti cr v and sc are depleted compared to late magmatic tourmaline of the same sample several tourmaline generations that precipitated from magmatic fluids can be distinguished with differing major and minor elements and ree patterns depending on the composition of the melt from which they were expelled from strongly zoned tourmaline allows for unraveling the hydrothermal history of a distinct location including ore precipitation the precipitation of sno2 in the study area was probably caused by mixing between acidic reduced sn bearing magmatic fluids and oxidized meteoric fluids which is in agreement with london and manning 1995 and williamson et al 2000 hence the ability of tourmaline composition to monitor changes in sn concentration and redox conditions in hydrothermal fluids has potential as an exploration tool

numerical study of a typhoon with a large eye model simulation and verification abstract typhoon winnie 1997 was the fourth supertyphoon in the western north pacific in 1997 in its mature stage an outer eyewall consisting of deep convection with a diameter of 370 km was observed by satellite and radar within this unusually large outer eyewall existed an inner eyewall which consisted of a ring of shallow clouds with a diameter of 50 km in this study typhoon winnie is simulated using a nested grid version of the fifth generation pennsylvania state university national center for atmospheric research psu ncar mesoscale model mm5 with an inner grid length of 9 km the model reproduces an outer cloud eyewall with a diameter of 350 km the simulated radar reflectivity and hourly precipitation are verified with satellite microwave infrared and cloud brightness temperature images analysis of the model results indicates that the large outer eyewall in many ways possesses the structure of a typical hurricane eyewall this includes strong tangential winds and radial inflow out

10be and9be in south atlantic dsdp site 519 relation to geomagnetic reversals and to sediment composition a high resolution10be profile has been measured on dsdp site 519 central south atlantic in order to search for changes in the flux of10be into a pelagic sediment during geomagnetic reversals as compared with times of constant magnetic polarity the decay corrected10be concentrations range from 1 to 9 108 at g the average10be flux rate is 5 108 at cm 2 kyr 1 9be and caco3 were measured on the same samples the10be vs depth curve is overall similar to the9be vs depth curve while the caco3 vs depth curve anticorrelates the beryllium isotope curves closely implying that be is carried mainly by the non caco3 phases of the sediment the positive correlation between10be and9be along with the fact that the average 10be 9be ratio of 5 5 10 8 is within the range of 10be 9be ratios reported for deep ocean water leads us to conclude 1 that the beryllium isotopes come close to an equilibrium in the open ocean and 2 that the 10be 9be in deep sea sediments with a low detrital component monitors the 10be 9be of deep ocean water through time relative increases of the 10be 9be ratio are observed in the vicinity of the geomagnetic reversals but the relationship between reversals and higher 10be 9be remains doubtful other mechanisms which could alter the 10be 9be ratio are discussed input of10be by melting of glacial ice changing input of9be due to changes in continental erosion changing deep ocean circulation changing scavenging activity at ocean margins but as yet no conclusive explanation for the observed behavior of the beryllium isotopes can be given

sensitivity and response of beryllium 10 in marine sediments to rapid production changes geomagnetic events a box model study the response and the sensitivity of the marine beryllium 10 flux to abrupt production changes e g caused by a geomagnetic event are investigated by using a simple box model the effect of mixing processes in the water column on the 10be flux is simulated and the influence of bioturbation on the sedimentary record is studied while the effect of the oceanic residence time is found to be small bioturbation can drastically change the shape and the amplitude of the modeled 10be peak the simulations indicate that 10be production peaks persisting for more than 1500 years are recorded well in deep sea sediments if bioturbation induced integration times are small tbio 1000 years while sediment cores with tbio 1000 years are found to be not well suited for stratigraphic purposes the results further show that the sedimentary 10be peak lags initial signal this time lag is almost independent of the event duration for tbio 1000 years ranging between about 400 and 600 years therefore the model results support the idea that marine 10be peaks corresponding to geomagnetic events can be used as a global time marker to match marine terrestrial and ice core chronologies on the millennial and if the time lag of 500 100 years is considered the submillennial timescale

the concentric eyewall cycle of hurricane gilbert abstract hurricane gilbert of 1988 formed an outer eyewall as it intensified rapidly toward a record minimum pressure of 888 hpa in the western caribbean the outer eyewall strengthened and contracted while the inner eyewall showed some signs of weakening before landfall on the yucatan peninsula remarkably both eyewalls survived passage over land but the storm was much weaker when it entered the gulf of mexico although the primary cause of weakening was passage over land the effect of the contracting outer eyewall may have contributed later the outer eyewall completely replaced the inner eyewall subsequently it contracted steadily but slowly as gilbert maintained nearly constant intensity over the cooler waters of the gulf before final landfall on the mainland of mexico

the benthic cycle of copper evidence from sediment trap experiments in the eastern tropical north pacific ocean abstract the benthic fluxes of 24 elements and components are calculated from sediment trap fluxes and sediment accumulation rates at manop sites h and m in the eastern tropical north pacific ocean in this paper we focus our discussion on our data for copper benthic flux estimates for copper are 0 7 and 1 4 nmol cm 2 yr at h and m respectively these results compare well with estimates from another trap deployment in the galapagos and modeling of pprewater and water column concentration data by other authors partitioning of near bottom cu flux indicates that the two sites receive similar amounts of primary cu flux flux from upper water column and resuspended cu flux only the site located on the east pacific rise site m shows any input of hydrothermal cu at site m 35 of the near bottom flux is due to some source other than primary resuspended or hydrothermal flux we speculate that dissolved cu from the sediments is readsorbed onto particles near the bottom at this site sequential leaching of trap material indicates that the flux of cu associated with organic matter using an operational definition ranges from 56 to 84 of the trap material this fraction of the total cu increases with depth in the water column probably through scavenging

trace and rare earth element geochemistry in tourmaline and cassiterite from the yunlong tin deposit yunnan china implication for migmatitic hydrothermal fluid evolution and ore genesis abstract yunlong tin deposit is a medial sized hydrothermal deposit in western yunnan province of china this deposit is unusual because the tin mineralization occurs exclusively within the migmatite bodies the genesis of the ore deposit has been hotly debated and various models have been proposed including granite related magmatic hydrothermal and migmatitic hydrothermal origins this paper reports a systematic trace and rare earth elements ree geochemical study in tourmaline and cassiterite from the orebodies and associated migmatites from the yunlong tin deposit tourmaline and cassiterite from this deposit show light ree lree enriched patterns with variable eu and ce anomalies consistent with hydrothermal fluids being derived from local high grade metamorphism and migmatization the data suggest that tourmaline and cassiterite were likely precipitated from migmatitic hydrothermal fluids and indicate that the yunlong tin deposit was probably formed during migmatitic hydrothermal process the high concentrations of transition metals e g sc ti v cr mn and zn in tourmalines are also consistent with this model the high concentrations of sn sr and especially sc v and cr in tourmalines can be used to discriminate tourmaline from barren deposits relative to those associated with economic tin mineralization

10be records of sediment cores from high northern latitudes implications for environmental and climatic changes the 10be records of four sediment cores forming a transect from the norwegian sea at 70 n core 23059 via the fram strait core 23235 to the arctic ocean at 86 n cores 1533 and 1524 were measured at a high depth resolution although the material in all the cores was controlled by different sedimentological regimes the 10be records of these cores were superimposed by glacial interglacial changes in the sedimentary environment core sections with high 10be concentrations 1 109 at g are related to interglacial stages and core sections with low10be concentrations 0 5 109 at g are related to glacial stages climatic transitions e g termination ii 5 6 are marked by drastic changes in the 10be concentrations of up to one order of magnitude the average 10be concentrations for each climatic stage show an inverse relationship to their corresponding sedimentation rates indicating that the 10be records are the result of dilution with more or less terrigenous ice rafted material however there are strong changes in the 10be fluxes e g termination ii into the sediments which may also account for the observed oscillations most likely both processes affected the 10be records equally amplifying the contrast between lower glacials and higher interglacials 10be concentrations the sharp contrast of high and low 10be concentrations at climatic stage boundaries are an independent proxy for climatic and sedimentary change in the nordic seas and can be applied for stratigraphic dating 10be stratigraphy of sediment cores from the northern north atlantic and the arctic ocean

evidence for an increase in cosmogenic 10be during a geomagnetic reversal reversals in the geomagnetic field which occur every few hundred thousand years represent a dramatic change in the earth s environment although there is no satisfactory theory for such reversals it is generally accepted that the dipole field intensity decreases to 20 of its normal value for a few thousand years during the change in direction1 because the galactic and solar cosmic rays which impinge on the earth s atmosphere are charged a significant fraction about half of them are deflected by the geomagnetic field2 at the time of a reversal this magnetic shielding is greatly reduced and it has been suggested that the increased flux of high energy particles could have effects on evolutionary3 or climatic4 processes for example the statistically significant coincidence in levels of some marine faunal extinctions and reversal boundaries in ocean sediments5 could be caused directly or indirectly by the decreased geomagnetic intensity during the reversal we report here evidence in marine sediments for an increase in cosmogenic 10be production in the earth s atmosphere during the brunhes matuyama reversal 730 000 yr ago in addition to confirming an increase in cosmogenic isotope production the results provide information on the magnitude and duration of the geomagnetic intensity decrease during such an event and the depth at which rmanent magnetism is acquired in marine sediments

boundary scavenging in the pacific ocean a comparison of 10be and 231pa concentrations of u th 231pa and 10be were measured in holocene sediments from two cores collected off the west coast of south america two cores from the east pacific rise two from the equatorial pacific and one from the south pacific central gyre our results together with data from 5 cores reported in the literature show that boundary scavenging plays a major role in the removal of 10be from the pacific ocean deposition rates of 10be at three margin sites are more than an order of magnitude greater than at sites of red clay accumulation in the deep central pacific deposition of 231pa is 4 to 5 fold greater at the margin sites the residence time of 10be with respect to chemical scavenging defined as its inventory in the water column divided by its rate of removal to the sediments varies regionally from 1000 years at the red clay sites in the deep central pacific to 100 years at the margin sites different factors control boundary scavenging of pa and be for example scavenging of 231pa is enhanced by metal oxide coatings of particles whereas this seems to have little influence on the scavenging of 10be 1990

on the importance of opal carbonate and lithogenic clays in scavenging and fractionating 230th 231pa and 10be in the ocean abstract the influence of particle composition on the scavenging of 230 th 231 pa and 10 be in the ocean is critically re examined based on the particle solution distribution coefficient k d data reported by chase et al earth planet sci lett 204 2002 215 229 our re examination shows that the k d s for these radionuclides are strongly influenced by the amount of lithogenic material lithogenics in particulates as reported previously by us and that a strong correlation between the lithogenic and carbonate contents in open ocean particulates results in an apparent non linear correlation between caco 3 and k d for each of the three radionuclides using a three end member model we estimate that the respective k d s g g of 230 th 231 pa and 10 be in the open ocean are 2 3 10 8 1 2 10 7 and 3 8 10 6 for lithogenics 1 0 10 6 1 0 10 5 and 3 0 10 4 for carbonate and 2 5 10 5 1 2 10 6 and 7 5 10 5 for opal suggesting that lithogenics have a much stronger affinity for any of the three nuclides than does carbonate or opal lithogenics and carbonate preferentially scavenge 230 th over 231 pa and 10 be whereas opal slightly favors 231 pa and 10 be over 230 th relative to lithogenics carbonate plays a very limited role in fractionating 230 th 231 pa and 10 be due to its orders of magnitude smaller k d values for the three nuclides our results indicate that fractionations between pa and th and between be and th through particle scavenging are mainly determined by the opal to lithogenic ratio in particulates rather than the opal to carbonate ratio suggested by chase et al

tourmaline b isotopes fingerprint marine evaporites as the source of high salinity ore fluids in iron oxide copper gold deposits carajas mineral province brazil the carajas mineral province in northern brazil contains a variety of world class 100 mt ore iron oxide copper gold iocg deposits including the only archean examples of this deposit class e g the igarape bahia alemao and salobo deposits tourmaline of schorldravite composition a common gangue mineral in these deposits precipitated shortly prior to and after the ore assemblage a boron isotope study of texturally different tourmaline from three iocg deposits igarape bahia salobo and sossego using secondary ion mass spectrometry sims provides new evidence in the long standing debate of magmatic versus non magmatic sources for the high salinity up to 50 wt nacl equiv of ore fl uids in these deposits values of 11 b from 14 to 26 5 for the igarape bahia and salobo deposits confi rm marine evaporite derived brines in the ore fl uids whereas lower 11 b values for the igarape bahia deposit 5 8 to 8 8 suggest that these fl uids may have mixed with an isotopically different hydrothermal fl uid or one that had a mixed boron source more variable and isotopically lighter boron in tourmaline from the sossego deposit 8 to 11 is attributed to mixed sources including light boron leached from felsic intrusive and volcanic host rocks and heavy boron derived from marine evaporites the boron isotope data indicate that the characteristic high salinity of the ore fl uids in the carajas mineral province was acquired by the interaction of hydrothermal fl uids with marine evaporites for iocg deposits that contain tourmaline as a common gangue mineral boron isotopes offer a valuable tool to constrain the high salinity source problem which is a critical issue in metallogenesis of iocg deposits worldwide

quasi conservative behaviour of 10be in deep waters of the weddell sea and the atlantic sector of the antarctic circumpolar current we present the first transect of dissolved 10be depth profiles across the antarctic circumpolar current acc in the atlantic sector north of the polar front the 10be concentrations increase continuously from very low values at the surface to values of up to 1600 atoms g at depth deep water 10be concentrations of particular water masses are consistent with earlier results obtained further north south of the polar front and in the weddell sea the distribution of 10be is also characterised by low surface concentrations but below 1000 m depth the concentrations are relatively constant and significantly higher up to 2000 atoms g than further north probably as a result of mixing and advection of water masses of pacific origin overall the deep water 10be distribution is obviously not significantly affected by scavenging processes or ice melt and comparison with the density distribution suggests that 10be can be viewed as a quasi conservative tracer this provides a tool for an improved understanding of the behaviour of other more particle reactive trace metals in the southern ocean such as 230th in deep waters north of the acc weddell gyre boundary awb 10be 230th has a relatively constant value 1 7 0 3 109 atoms dpm over a wide density range whereas south of the awb the ratio is significantly lower 1 1 0 2 109 atoms dpm this normalisation to 10be corroborates that 230th is enriched by 50 due to accumulation south of the awb as a consequence of minimal particulate fluxes the quasi conservative behaviour deduced from our results also implies that 10be can only be used as a tracer for southern ocean particle fluxes in the past if ocean circulation patterns and water mass residence times did not change significantly

response of manganese in the ocean to the climatic cycles in the quaternary profiles of the 230th concentration in mn crusts from the central pacific ocean measured at extremely high depth resolution reveal that the growth rates of mn crusts are influenced by climate based on a constant flux model the sections of maximum 230th concentration correspond to periods of slow growth during glacial stages fast growth occurred during interglacial stages 1 5 and 7 probably due to a larger supply of mn oxides from the water column high resolution profiles of 230th and 10be in sediment cores from high biological productivity areas display radioisotope maxima in the interglacial stages and minima during glacial periods the ratio of the fluxes of 10be 230th being 4 the only exceptions are observed at 135 and 270 kyr b p where the ratio of the fluxes is as low as 0 1 to 0 3 we presume that this 230th anomaly reflects short periods of time at the end of glacials when precipitation of mno2 occurred this hypothesis is confirmed by peaks of mn observed in sediment cores mainly at the transitions from glacial to interglacial stages the standing crops of mn in these layers suggest release of mn2 from the sediments during glacial stages and buildup of mn in the water column to concentrations of up to 10 mol l

cr bearing tourmaline associated with emerald deposits from swat nw pakistan genesis and its exploration significance carbonate talc altered ultramafic and mafic rocks of the obducted oceanic lithosphere along the main mantle thrust in the swat valley host emerald deposits and are invaded by quartz veins and stockworks both the quartz veins and carbonate talc altered rocks contain discrete grains and clusters of tourmaline crystals which may be associated with emerald and or chromian muscovite tourmalines from the mingora and gujar kili emerald mines and the spin obo kuh area are ni bearing cr rich dravites and oxy dravites that exhibit substantial chemical variability with 2 0 2 5 atoms per formula unit apfu mg relatively low al 4 8 5 8 apfu high cr 0 5 1 8 apfu high cr cr al ratios of 0 08 0 28 significant amounts of ni up to 0 11 apfu and variable calculated w site o 2 0 2 0 8 apfu the mechanisms that appear to control the tourmaline chemistry at these localites are combinations of the dominant substitution al cr with lesser amounts of the mg oh 1 al cr o 2 and al 3 fe 3 substitutions relative to the mingora gujar kili and spin obo kuh areas the charbagh tourmalines are oxy dravites that have comparable mg contents 2 2 2 3 apfu with variable calculated w site o 2 0 6 0 9 apfu but are more fe rich 0 5 apfu and al rich 6 0 6 3 apfu with low cr 0 00 0 01 apfu and ni contents 0 01 0 02 apfu the mechanism that appears to control the variable chemistry of the charbagh tourmalines is primarily mg oh 1 al o 2 the chemical characteristics of tourmalines from the various localities relate most clearly to differences in host rock chemistry tourmalines from the carbonate talc altered ultramafic mafic rocks and the invasive quartz veins have a common hydrothermal origin associated with emplacement and crystallization of younger granitoids furthermore the occurrence of swat emeralds in quartz tourmaline chromian muscovite veins suggests that the tourmaline is cogenetic with emerald formation the quality and quantity of swat emeralds depend on the 1 host rock composition and 2 nature of the hydrothermal fluids large deposits of gem quality emerald occur in carbonate altered ultramafic rocks which also contain cr rich dravites and oxy dravites this suggests that the presence of high cr magnesian tourmalines particularly in magnesite talc altered ultramafic rocks can represent a criterion for further emerald exploration in the lower swat region of pakistan and comparable ultramafic hosted emerald producing regions

the influence of particle composition and particle flux on scavenging of th pa and be in the ocean we have examined the relative affinity of th pa and be for sorption from seawater onto particles of variable composition opal carbonate lithogenic particles and organic carbon nuclide concentrations in particles collected from time series sediment traps were normalized by the dissolved nuclide concentration in the overlying water column in order to compute partition coefficients under conditions spanning a wide range of particle flux and particle composition our results suggest that the affinity of particles for pa and be increases with their increasing opal content and decreasing carbonate content while the affinity of particles for th increases with increasing carbonate content and decreases with increasing opal content we find no correlation between the aluminosilicate content of particles and their affinity for scavenging of any of these elements extrapolating to a pure caco3 end member the partition coefficient for th 9 0 106 g g 1 is 40 times greater than for pa and roughly 100 times greater than for be whereas for a pure opal end member the partition coefficient for th 3 9 105 g g 1 is slightly less than that for pa and be partition coefficients decrease with increasing particle flux in open ocean settings but not in an ocean margin region this kinetic effect reflects the increasing contribution of unaltered surface material reaching the sediment traps as particle flux increases the degree of fractionation between pa and th and between be and th depends on the opal carbonate rain ratio these results challenge the use of sedimentary 231pa 230th and 10be 230th ratios as simple proxies of particle flux however the strong dependence of nuclide scavenging on the opal carbonate rain ratio may provide a needed tool for reconstructing past changes in planktonic community composition

chemical and boron isotope compositions of tourmaline in the hadamiao porphyry gold deposit inner mongolia china abstract the hadamiao porphyry gold deposit in inner mongolia china is located in the northern margin of the north china craton ncc tourmaline is a common mineral in hydrothermal veins and granitic rocks contemporaneous with the mineralized granite porphyry in this deposit the tourmaline can be divided into six types including magmatic tourmaline tur m1 in granite porphyry dikes magmatic hydrothermal transitional tourmaline tur m2 in nodular granitic rocks and hydrothermal tourmalines in early tourmaline veins tur v1 gold bearing quartz tourmaline chalcopyrite veins tur v2 breccia cements tur v3 and late carbonate quartz veins tur v4 the gold mineralization is closely related to the occurrence of tur v2 almost all the tourmalines from the hadamiao deposit belong to the alkali group and show a schorlitic dravitic composition except for some tur m1 belonging to uvite the concentrations of most elements in different tourmaline types overlap tur m1 has higher ca w th u pb mn and zr contents than other types and the hydrothermal tourmalines v1 v4 show slightly higher ba cu and y contents than tur m1 and tur m2 the concentration of au in tur m1 and tur m2 can reach up to 80 ppb and is higher than that in tur v1 the au content in tur v2 is an order of magnitude higher than that in other stages of tourmaline systematic contrasts in major and trace element compositions between magmatic and hydrothermal tourmalines are attributed to the assimilation of the country rock by the magmatic hydrothermal system the six types of tourmaline exhibit variable 11b values ranging from 8 7 to 21 2 tur m1 shows the highest 11b values of 15 1 to 21 2 and tur v2 yields the lowest values ranging from 8 7 to 5 4 the boron probably came from two sources with different isotopic compositions one with high positive 11b values and the other with negative 11b values magmatic hydrothermal fluids could have provided isotopically light boron for hydrothermal tourmalines whereas the heavy boron in magmatic tourmaline was probably derived from marine carbonates that are widespread in the study area the magma related to the mineralization and the one containing magmatic tourmaline may have experienced different degrees of interaction with wall rocks resulting in the diversity of 11b values in hadamiao tourmaline

geochronology geochemical and sr nd hf pb isotopic compositions of the granitoids in the yemaquan orefield east kunlun orogenic belt northern qinghai tibet plateau implications for magmatic fractional crystallization and sub solidus hydrothermal alteration abstract a general consensus has emerged that high field strength elements hfse can mobile to some extent in a hydrothermal fluid however there are hot debates on whether sub solidus hydrothermal alteration can lower the nb ta ratio in evolved melts in this study we present petrography geochronology and geochemistry of the barren and mineralized rocks in the yemaquan skarn iron deposit northern qinghai tibet plateau to probe magmatic hydrothermal transition the barren rocks consist of diorites granodiorites granites and syenogranites whereas the porphyritic granodiorites are associated with mineralization for an excellent consistency between the magmatic zircon u pb age 225 2 ma and the hydrothermal phlogopite 40 ar 39 ar age 225 1 5 ma the sr nd hf pb isotopic data demonstrate that the yemaquan granitoids are originated from a relatively homogenous enriched mantle with different degrees of crust contamination assimilation fractional crystallization afc trace elements signatures indicate that the porphyritic granodiorites related to mineralization display amphibole crystallization for high water contents whereas the barren granites have gone through biotite crystallization due to potassium enrichment by continuous upper crust contamination both of which are responsible for their nb ta ratios respectively modeling results suggest that a basaltic melt with nb ta ratio of 15 3 can reach a minimum nb ta ratio of 12 in the producing granodioritic melt by amphibole fractional crystallization based on partition coefficients of nb and ta between amphibole and melts from previous experiments this may explain the average nb ta ratio 13 7 of the barren granodiorites while it cannot account for the average nb ta ratio 8 4 of the mineralized porphyritic granodiorites and it is even lower than that of the granites 10 3 with biotite fractional crystallization exsolution of a magmatic hydrothermal fluid is inevitable when a water saturated magma emplaced in shallow crust leading to a transportation of certain chemical components from the magmatic melts to exsolved fluids because nb seems more mobile than ta in fluorine bearing fluids we contend that a preferentially transport nb over ta by sub solidus hydrothermal alteration can further lower the nb ta ratios of the mineralized porphyritic granodiorites which may also result in a broad range of hfse contents and their ratios in the altered porphyritic granodiorites formed in a post magmatic process

the global average production rate of10be precipitation collected in continuously open containers for about a year at seven sites around the united states was analyzed for10be 90sr 210pb and238u based on these data and long term precipitation 90sr and210pb delivery patterns the stratospheric tropospheric and recycled10be components in the collections were estimated and the global10be production rate was assessed single station production rate estimates range from 0 52 106 atoms cm 2 yr 1 to 2 64 106 atoms cm 2 yr 1 the mean value is 1 21 106 atoms cm 2 yr 1 with a standard error of 0 26 106 atoms cm 2 yr 1

major and trace element geochemistry of tourmalines from archean orogenic gold deposits proxies for the origin of gold mineralizing fluids abstract orogenic style gold mineralizations in the archean hattu schist belt e finland are present in all major host rock lithologies including epiclastic sedimentary and volcanogenic rocks as well as felsic intrusives the gold mineralizations occur as dissemination in altered wall rocks and within hydrothermal quartz veins hydrothermal tourmalines are often associated with the gold mineralizations occurring in the quartz veins as alteration minerals in contacts of the metasedimentary host rocks and quartz veins but also within mineral assemblages of the metasedimentary and magmatic rocks we characterize and compare the major trace and rare earth element chemistry of these tourmalines in order to evaluate their suitability as a petrogenetic tool for tracing the fluid sources of the hydrothermal system by comparing the chemistry of tourmalines from gold mineralization with those from metamorphic and magmatic host rocks we test whether tourmaline composition can be used to identify the source rocks of the gold transporting hydrothermal fluids all analyzed tourmalines belong to the alkali super group and plot along the schorl dravite join the hydrothermal tourmalines have li sr and v concentrations comparable to metamorphic tourmalines and clearly distinct from magmatic tourmalines because the concentrations of ni pb cr mn ga zn and sn show a wide overlap between magmatic metamorphic and hydrothermal tourmalines these elements do not permit to discriminate between different source rocks the co variations of many elements in hydrothermal tourmalines when plotted against li show more similarity to metamorphic tourmalines and the whole rock compositions of metasedimentary and metavolcanic host rocks than to their magmatic counterparts this indicates that the major and trace element composition of hydrothermal tourmalines in the hattu schist belt is predominantly controlled by the host rocks and local fluid rock interactions and does not reflect the distal fluid sources the effect of local fluid rock interaction is also manifested by the ree patterns of tourmalines the magmatic tourmalines have distinct lree enriched patterns resembling the whole rock ree patterns of granitic intrusives while the metamorphic and hydrothermal tourmalines have flat or weakly fractionated patterns similar to metavolcanic and metasedimentary host rocks taken together the tourmaline data suggest that hydrothermal tourmalines associated to gold mineralizing fluids are most likely genetically related to metamorphic rock sources without important contributions of magmatic fluids and that local fluid rock interaction exerted a major control on tourmaline chemistry

beryllium 10 thorium 230 and protactinium 231 in galapagos microplate sediments implications of hydrothermal activity and paleoproductivity changes during the last 100 000 years biogenic particle fluxes from highly productive surface waters boundary scavenging and hydrothermal activity are the main factors influencing the deposition of radionuclides in the area of the galapagos microplate eastern equatorial pacific in order to evaluate the importance of these three processes throughout the last 100 kyr concentrations of the radionuclides 10be 230th and 231pa and of mn and fe were measured at high resolution in sediment samples from two gravity cores klh 068 and klh 093 high biological productivity in the surface waters overlying the investigated area has led to 10be and 231pa fluxes exceeding production during at least the last 30 kyr and probably the last 100 kyr however during periods of high productivity at the up welling centers off peru and extension of the equatorial high productivity zone a relative loss of 10be and 231pa may have occurred in these sediment cores because of boundary scavenging the effects of hydrothermal activity were investigated by comparing the 230thex concentrations to the mn fe ratios and by comparing the fluxes of 230th and 10be which exceed production the results suggest an enhanced hydrothermal influence during isotope stages 4 and 5 and to a lesser extent during isotope stage 1 in core klh 093 during isotope stages 2 and 3 the hydrothermal supply of mn was deposited elsewhere probably because of changes in current regime or deep water oxygenation a strong increase of the mn fe ratio at the beginning of climatic stage 1 which is not accompanied by an increase of the 230thex concentration is interpreted to be an effect of mn remobilization and reprecipitation in the sediment

10 be profiles in seawater a knowledge of the marine geochemical cycle of 10be is basic to the use of this long lived cosmogenic radioisotope half life 1 5 myr in geochronological and geophysical studies1 3 the first attempts at measuring 10be in seawater were made only recently using nuclear accelerator spectrometry and six concentration values from four locations have been reported4 6 this data base must be expanded to include detailed water column profiles so that the behaviour of 10be in the ocean can be more fully described a parallel case in point is the recent measurement7 of a detailed oceanic profile for the stable 9be we report here two water column profiles of 10be one in the drake passage near antarctica and the other in the san nicolas basin about 100 km off the coast of southern california the san nicolas basin profile clearly demonstrates the regulation of 10be distribution by particulate cycling the data confirm the earlier suggestion4 of particle uptake of 10be in the surface ocean they also furnish evidence for regeneration of 10be across the thermocline and near the sea floor and for mid water scavenging

10be and ba concentrations in west african sediments trace productivity in the past particle reactive elements are scavenged to a higher degree at ocean margins than in the open ocean due to higher fluxes of biogenic and terrigenous particles in order to determine the influence of these processes on the depositional fluxes of10be and barium we have performed high resolution measurements on sediment core geob 1008 3 from the congo fan because the core is dominated by terrigenous matter supplied by the congo river it has a high average mass accumulation rate of 6 5 cm kyr biogenic10be and ba concentrations were calculated from total concentrations by subtracting the terrigenous components of10be and ba which are assumed to be proportional to the flux of al2o3 the meanba al weight ratio of the terrigenous component was determined to be 0 0045 the unusualy high terrigenous10be concentrations of 9 1 109 atoms g al2o3 are either due to input of particles with high10be content by the congo river or due to scavenging of oceanic10be by riverine particles the maxima of biogenic10be and ba concentrations coincide with maxima of the paleoproductivity rates time series analysis of the10be and of ba concentration profiles reveals a strong dominance of the precessional period of 24 kyr which also controls the rates of paleoproductivity in this core during the maxima of productivity the flux of biogenic ba is enhanced to a larger extent than that of biogenic10be applying a model for coastal scavenging we ascribe the observed higher sensitivity of ba to biogenic particle fluxes to the fact that the ocean residence time of ba is approximately 10 times longer than that of10be

examination of hydrothermal influences on oceanic beryllium using fluids plume particles and sediments from the tag hydrothermal field we have carried out a comprehensive study of the distributions of9be and the cosmogenic radionuclide10be in fluids nearfield sediments and neutrally buoyant plume particles associated with the tag hydrothermal field these results coupled with previously published uranium decay series radionuclide distributions 1 2 suggest that the level of mno2 in iron oxide rich sediments and particles may play a role in be scavenging in addition the data are used to quantify the net effects of nearfield coprecipitation with fes and of scavenging by iron oxyhydroxide plume particles on the oceanic balance of the be isotopes these calculations suggest that hydrothermal input of9be is nearly balanced by nearfield and plume removal processes and that hydrothermally induced scavenging has a negligible effect on the oceanic10be budget

episodic tourmaline growth and re equilibration in mica pegmatite from the bihar mica belt india major and trace element variations under pegmatitic and hydrothermal conditions mica pegmatites from the bihar mica belt contain three distinct generations of tourmaline the major element composition substitution vectors and trajectories within each group are different which indicates that the three types of tourmalines are not a part of one evolutionary series rather the differences in their chemistries as well their mutual microtextural relations can be best explained by growth of tourmaline from pegmatitic melts followed by episodic re equilibration during discrete geological events the euhedral coarse grained brown type i tourmaline cores have relatively high ca mg x mg c 0 37 and al with correlated variation in sr sc ti zr y cr pb and rare earth elements rees they are inferred to have crystallized from pegmatitic melts monazites included within these tourmalines give chemical ages of 1290 1242 ma interpreted to date the crystallization of the pegmatitic tourmaline the bluish type ii and greyish type iii tourmalines with low ca and mg contents x mg 0 16 0 27 and high zn sn nb ta and na formed by pseudomorphic partial replacement of the pegmatitic tourmaline via fluid mediated coupled dissolution reprecipitation are ascribed to a hydrothermal origin the ages obtained from monazites included in these tourmalines indicate two alteration events at c 1100 ma and c 950 ma the correlated variation of ca mg and fe and the trace elements sr sn sc zn and ree within the tourmalines indicates that the trace element concentrations of tourmaline are controlled not only by the fluid chemistry but also by coupled substitutions with major element ions

origin of the atypical puy les vignes w breccia pipe massif central france constrained by trace element and boron isotopic composition of tourmaline abstract the puy les vignes w deposit is an atypical wolframite bearing hydrothermal breccia pipe hosted in migmatitic biotite sillimanite gneisses in the northwestern french massif central the deposit is characterized by volumetrically important tourmaline alteration allowing to investigate the fluid evolution of the ore forming hydrothermal system four generations of hydrothermal tourmaline tur 1 tur 4 formed during pre syn and post mineralization stages were identified based on detailed petrographic observations and were analyzed in situ for their chemical and boron isotopic compositions at the grain scale tourmaline commonly shows oscillatory zoning and dissolution textures resulting from a multi stage crystallization in a fluid dominated system the different generations of hydrothermal tourmaline have dravite schorl compositions and show similar major and trace element contents falling into the field of metamorphic rocks high concentrations of v cr sr and low concentrations of li sn in tourmaline suggest a metamorphic dominated origin of these elements the boron isotopic compositions of tourmaline range between 13 3 and 7 8 and cannot unambiguously distinguish between a magmatic and a metamorphic fluid origin our data indicate that the chemical and boron isotopic composition of tourmaline was dominantly controlled by high temperature fluid rock interactions between the metamorphic basement and boron rich reduced and low salinity hydrothermal fluids based on these results we propose a fluid evolution scenario for the puy les vignes ore forming hydrothermal system release of magmatic hydrothermal fluids from an unexposed peraluminous leucogranite at ca 324 ma is proposed as the main mechanism responsible for early greisenization and formation of disseminated tur 1 this episode was followed by massive tourmalinization and hydraulic brecciation of the overlying gneisses producing a tourmaline rich tur 2 crackle breccia by interactions with boron rich hydrothermal fluids fluid assisted reopening and collapse of the former tourmalinite at ca 318 ma yielded a matrix supported quartz tourmaline breccia pipe and formation of wolframite bearing quartz veins accompanied by deposition of tur 3 finally post ore hydraulic fracturing at ca 300 ma led to formation of tourmaline rich microbreccias tur 4 possibly from metamorphic fluids

boron recycling in the continental crust of the central andes from the palaeozoic to mesozoic nw argentina whole rock chemical composition and 11b 10b isotope ratios in tourmaline was investigated to study the geochemical recycling of boron during the evolution of the andean basement from the palaeozoic to mesozoic in the basement cambrian to ordovician high grade paragneisses migmatites and orthogneisses the eocambrian puncoviscana formation and paleozoic mesozoic granitoid igneous rocks whole rock b contents are generally below 100 ppm but b contents of 1 wt are found in cogenetic aplite and pegmatite dikes and in tourmaline quartz rocks in the metasedimentary rocks no systematic variation in b content because of metamorphic grade and no correlation of b with other incompatible elements are apparent tourmalines from the high grade metamorphic basement yield 11b values ranging from 11 2 to 6 8 and isotope fractionation during migmatisation was small metamorphic tourmalines from the puncoviscana formation have 11b values between 6 3 and 5 8 the calculated corrected for fractionation 11b values of 6 to 2 for the sedimentary protolith of the metamorphic basement indicate a continental b source with subordinate marine input tourmalines from palaeozoic and mesozoic granitoids display an identical range of 11b values from 12 to 5 3 and indicate a similarly homogeneous b source throughout time tourmalines from pegmatites and tourmaline quartz rocks record the average 11b values of the parental granitic magma we assume that b in the palaeozoic and mesozoic granitoids is derived from the local metamorphic basement supporting the hypothesis that recycling of the lower palaeozoic crust is the dominant process in granitic magma formation from palaeozoic to mesozoic

distribution of10be and9be in the pacific ocean abstract the vertical distributions of10be and9be at three locations in the pacific 25 n 170 e 17 n 118 w 3 s 117 w are presented the results show that both isotopes exhibit nutrient like profiles from the surface to the bottom the increase for10be is two to threefold and that for9be is about fivefold while the inter station variations in surface water concentrations may reach a factor of two deep water values tend to be much more uniform averaging about 2000 atoms g for10be and 30 pm for9be a similar situation applies to the10be 9be ratio it varies approximately from 1 to 3 10 7 atom atom at shallow depths but tends toward a value close to 1 1 10 7 in the deep ocean the variation of10be 9be can be viewed as resulting from the fact that10be in a given parcel of water consists of two components recycled and primary the recycled component is that part of10be which has reached tracer equilibrium with9be as opposed to the primary component which upon entering the sea from the atmosphere has yet to equilibrate with9be through particle cycling and mixing processes it is estimated that 70 to nearly 100 of10be at the three stations are being recycled and the recycled beryllium bears an atomic ratio of10be 9be close to 1 10 7 the oceanic residence time of be is of the order of 1000 4000 years comparable to or slightly longer than the ocean mixing time

fluid inclusions and stable isotope study of quartz tourmaline veins associated with beryl and emerald mineralization kafubu area zambia abstract the kafubu emerald area in zambia is an important producer of gemstone quality emeralds these are hosted mostly by metasomatic phlogopite rich zones max 2 m wide that rim numerous pegmatite dykes and epigenetic quartz tourmaline veins in mg rich metabasites where these dykes veins occur in other rock types the phlogopite rich zones are either missing or are very narrow and free of emeralds three types of hydrothermal quartz tourmaline mineralization were identified banded fine grained rock discordant to semiconcordant veins and late veins a fluid inclusion study of the discordant type of veins revealed the presence of aqueous carbonic and aqueous fluids the earliest fluids mostly trapped in the quartz rarely in beryl represent complex h 2 o co 2 n 2 ch 4 nacl cacl 2 mixtures x co2 0 25 to 0 04 with traces of n 2 and ch 4 only generally as for their salinity low medium and high salinity fluids were distinguished 0 10 12 25 and 34 wt nacl eq respectively each salinity class usually comprises both aqueous carbonic and aqueous fluids solid phases present in inclusions were studied by raman and or by sem edx daughter phases include halite sylvite and fe mn carbonate accidental phases are quartz beryl carbonate nahcolite pyrophyllite and muscovite the oxygen isotope composition 18 o of quartz and tourmaline is quite homogeneous 10 9 1 and 8 4 0 7 smow respectively and yield vein formation temperatures of 350 450 c and parent fluid composition 5 to 7 smow three evolution stages of quartz tourmaline beryl mineralization are inferred from fluid isochores and isotope thermometry early 620 400 mpa and 450 350 c main 400 150 mpa and 450 350 c and late 250 200 mpa and 350 280 c the early stage includes formation of banded quartz tourmaline rocks and of some quartz tourmaline veins most of the studied quartz tourmaline veins and all studied beryls were formed within the main stage late stage corresponds to the formation of late quartz tourmaline veins with lamellar tourmaline quartz intergrowths

particle mixing rates in sediments of the eastern equatorial pacific evidence from 210pb 239 240pu and 137cs distributions at manop sites abstract particle mixing rates db calculated from excess 210pb gradients in sediments of the east equatorial pacific range from 0 04 to 0 5 cm2 y with variation of a factor of 3 4 at a single site diffusion of the 236ra daughter 222rn may affect 210pb distributions under conditions of slow mixing and low 210pb flux to the seafloor as shown by a siliceous ooze clay core which contained the fallout radionuclides 239 240pu and 137cs but no excess 210pb relative to 226ra there is no clear relationship between 210pbderived mixing rates and sediment type accumulation rate or organic carbon flux to the sediments comparison of 210pb mixing rates with those calculated from 239 240pu and 137cs distributions reveals better agreement for a pulse input of the fallout radionuclides db 0 03 0 4 cm2 y than for continuous input at a constant rate db 0 1 1 6 cm2 y although the pu and 137cs data are better fit by the latter model the agreement may be fortuitous because 239 240pu and 137cs appear significantly deeper than 210pb in at least one core tracer separation could be caused by particle size selective mixing by the benthic fauna or by chemical mobilization if the fallout radionuclides are scavenged from surface waters by large organic rich particles such as fecal pellets their release and migration may result from decomposition of the carrier in surface sediments either a relatively unreactive form of pu e g oxidized pu has been released by this process or a one dimensional model is inadequate to explain its observed penetration into the sediments activity ratios of 239 240 pu 137 cs in the sediments decrease with increasing north latitude and the trend reflects higher fluxes of 239 240pu near the weapons test site at christmas island 2 n the 239 240 pu 137 cs ratios and fluxes to the sediment assuming constant input at the siliceous ooze red clay site are consistent with published sediment trap data from a nearby site thus if fallout radionuclide fluxes to the sea floor were higher in the past both 239 240pu and 137cs have been released from sinking particles

the diversity of b isotope variations in tourmaline from rare element pegmatites in the borborema province of brazil abstract tourmaline chemical and b isotope compositions have been determined from 4 rare element pegmatites and 1 barren pegmatite in the borborema pegmatite province of ne brazil and also from a leucogranite considered to be parental to the pegmatites the rare element pegmatites are of the lct lithium cesium tantalum class and they display a classic zoning structure with tourmaline present in all units but the quartz core tourmaline major element composition varies systematically from schorl dravite in the border and wall zones to varicolored elbaite in the inner zones consistent with increasing differentiation of a pegmatite magma previous studies supposed a continuous variation in li contents from schorl dravite to elbaite but the sims data instead show a major gap between 0 07 wt and 0 72 wt li 2 o followed by a continuous variation to the maximum value of 1 8 wt the barren pegmatite and leucogranite contain schorl dravite only the full range of 11 b values in tourmaline from the borborema pegmatites is from 20 2 to 1 6 n 62 which comes close to the total known diversity of pegmatite tourmalines worldwide and is much broader than the range of the associated leucogranite 15 1 to 13 4 n 3 however more than 80 of the pegmatite tourmalines define a main range between 17 and 9 11 b the average value of the latter 13 5 s d 2 3 n 50 is identical within error with the leucogranite supporting suggestions of a genetic relationship the b isotope compositions of barren and mineralized pegmatites overlap within the main range we find no correlation between chemical composition and b isotope ratios famous for the borboreman province are gem quality crystals of blue paraiba type elbaite the 11 b values of blue tourmaline from the capoeira pegmatite also fall within the main range 16 4 to 11 9 n 5 four of the 5 pegmatites studied are heterogeneous in 11 b with typical variations of 6 however there are no consistent trends in these examples from outer to inner units or from core to rim of zoned crystals that would fit any one scenario of melt evolution instead the factors controlling b isotope evolution e g crystallization fluid exsolution or mixing with external b reservoirs appear to vary locally and can be specific to the individual pegmatite or internal zone within it for example the carrascao pegmatite shows a shift from higher to lower 11 b values in tourmaline from the outer to inner zone 14 9 to 9 1 vs 20 2 to 13 9 resp and there is a parallel trend of lighter rims in zoned elbaite from the inner intemediate zone these trends are consistent with 11 b removal by tourmaline crystallization and or fluid exsolution an opposite trend in isotopic variation was found in zoned tourmaline from the wall zone of the boqueirao pegmatite whose core compositions are in the main range 15 1 to 14 9 and whose rims are much heavier 5 5 to 1 7 similarly high 11 b values about 10 beyond the main range were found in wall zone tourmaline in the barren fazenda turmalina pegmatite 6 0 to 1 6 the patchy distribution of heavy b isotopic compositions found only in outer zones of pegmatites and the strong isotopic contrast with the main range suggest the possibility of mixing with heavy b from the country rocks a potential source being layers of marble and calc silicate rocks

beryllium in the water column of the central north pacific the existence of the cosmogenic radioisotope of beryllium 10be t1 2 1 5 myr was first confirmed1 2 almost 25 yr ago subsequently merrill et al 3 worked out the sedimentary geochemistry of the stable isotope of the element 9be the geochronological potential of 10 be could not be exploited however because of its extremely low abundance global average production rate 1 08 atoms cm 2 min 1 4 and the difficulties associated with the analysis of the stable species 9be particularly in natural waters this situation is changing dramatically with the application of accelerator techniques to the detection of the radioisotope5 it thus becomes important to obtain a detailed understanding of the geochemistry of 9be since the potential use of the stable isotope for normalization purposes would significantly enhance the usefulness of the radioactive species in dating studies we report here the first detailed profile for 9be in the oceanic water column

tourmaline as a recorder of magmatic hydrothermal evolution an in situ major and trace element analysis of tourmaline from the qitianling batholith south china four types of tourmaline in the qitianling granitic batholith south china were identified in this study euhedral disseminated tourmaline dt type in the early stage of granite consolidation typical interstitial nodular tourmaline nt type formed late in the crystallization history radial tourmaline veinlet rt type and vein tourmaline vt type of hydrothermal origin we performed major and trace element analysis by in situ electron microprobe and laser ablation inductively coupled plasma mass spectrometry on these four tourmaline types compositionally these tourmalines fall into the alkali group and schorl dravite solid solution series there is clear correlation between trace and major elements in vt type tourmalines likely related to co variations of these elements in the hydrothermal fluid from which the tourmaline precipitated tourmaline from granites displays low ree abundances and negative lree trends positive eu anomalies and hree below or close to their detection limits the dt type tourmalines show a positive eu anomaly which is probably due to a preferential incorporation of eu2 over eu3 ree depletion in nt type tourmalines may reflect co crystallization of ree rich minerals the positive eu anomaly in nt type tourmalines is due to late stage release of eu2 caused by tourmaline replacement of early feldspar vein tourmalines rt and vt type display similar slopes from la to nd without an eu anomaly the chondrite normalized ree patterns in tourmalines from veins display a concave upward shaped mree depleted pattern with minimum values at ho increasing steadily to lu and may reflect the ree characteristics of the precipitated medium hree enrichment in hydrothermal fluid can be attributed to the formation of ree fluoride complexes during the internal fluid evolution

beryllium 10 in continental sediments abstract the concentration of 10 be has been measured in 10 samples taken from a transect of surface sediments beginning in the atchafalaya river and extending across the bay 136 km into the gulf of mexico if corrected for a lower retentivity of sand for be they have a concentration that is constant within 13 this concentration is about an order of magnitude smaller than that of deep ocean sediments for comparison measurements of 10 be in rainwater in a sample of soil and in a deep ocean core were made

relationship between typhoons with concentric eyewalls and enso in the western north pacific basin abstractthe typhoons with concentric eyewalls ce over the western north pacific in different phases of the el nino southern oscillation enso between 1997 and 2012 are studied they find a good correlation 0 72 between the annual ce typhoon number and the oceanic nino index oni with most of the ce typhoons occurring in the warm and neutral episodes in the warm neutral episode 55 50 of the typhoons possessed a ce structure in contrast only 25 of the typhoons possessed a ce structure in the cold episode the ce formation frequency is also significantly different with 0 9 0 2 ces per month in the warm cold episode there are more long lived ce cases ce structure maintained more than 20 h and typhoons with multiple ce formations in the warm episodes there are no typhoons with multiple ce formations in the cold episode the warm episode ce typhoons generally have a larger size stronger intensity and smaller variation in convective activity and intensity this may be due to the fact

trace element systematics of tourmaline in pegmatitic and hydrothermal systems from the variscan schwarzwald germany the importance of major element composition sector zoning and fluid or melt composition article an extensive data set on the compositional variation of tourmaline from granitic pegmatites from migmatitic gneisses and from various types of hydrothermal veins from the schwarzwald germany is provided the investigated tourmalines are members of the alkali and x vacant groups representing mostly dravite schorl solid solutions with some analyses belonging to the foitite mg foitite series oxygen isotope data on quartz tourmaline pairs indicate formation temperatures between 550 and 350 c for most of the quartz tourmaline veins most of the tourmalines show strong sector zonation fractionating certain major e g na mg minor e g ti ca and trace elements e g sr pb ree among the different crystallographic sectors of the crystals we conclude that comparison of tourmaline compositions for petrogenetic interpretations must be based on the concentrations in the neutral a sector in order to eliminate the effects of intra crystalline fractionation most trace element contents vary over several orders of magnitude with median concentrations generally be tween 0 1 and 10 g g the highest concentrations are found for zn v sr sc sn and li median concentrations of several tens to hundreds of g g whereas very low median concentrations b0 1 g g were found for u th bi tl and cs the concentration of several trace elements e g sr ree co correlates with the major element composition of the tourmaline which implies potential crystal chemical effects on their incorporation conse quently the general assumption that tourmaline is a passive monitor for the chemical compositions of the melts or fluids from which it crystallizes has to be questioned nevertheless our study demonstrates that the trace element composition of tourmaline allows to distinguish between geochemically distinct fluid sources and the trace element composition of tourmaline may therefore be used to unravel the chemical complexity of granite related hydrothermal systems

tourmaline geochemistry and δ11b variations as a guide to fluid rock interaction in the habachtal emerald deposit tauern window austria tourmalines from the habachtal emerald deposit in the eastern alps formed together with emerald in a ductile shear zone during blackwall metasomatism between pelitic country rocks and a serpentinite body electron microprobe and secondary ion mass spectrometric sims analyses provide a record of chemical and b isotope variations in tourmalines which represent an idealized profile from metapelites into the blackwall sequence of biotite and chlorite schists tourmaline is intermediate schorl dravite in the country rock and become increasingly dravitic in the blackwall zones while f and cr contents increase and al drops metasomatic tourmaline from blackwall zones is typically zoned optically and chemically with rim compositions rich in mg ti ca and f compared with the cores the total range in 11b values is 13 8 to 5 1 and the within sample variations are typically 3 5 both of these ranges are beyond the reach of closed system fractionation at the estimated 500 550 c conditions of formation and at least two boron components with contrasting isotopic composition are indicated a key observation from tourmaline core analyses is a systematic shift in 11b from the country rock 14 to 10 to the inner blackwall zones 9 to 5 we suggest that two separate fluids were channeled and partially mixed in the habachtal shear zone during blackwall alteration and tourmaline emerald mineralization a regional metamorphic fluid carried isotopically light boron as observed in the metapelite country rocks the other fluid is derived from the serpentinite association and has isotopically heavier boron typical for morb or altered oceanic crust

diverse tourmaline compositions from orogenic gold deposits in the hutti maski greenstone belt india implications for sources of ore forming fluids the late archean hutti maski greenstone belt hosts the largest operational gold mine in india at hutti as well as two satellite mines at hira buddini and uti tourmaline is a common accessory mineral in the auriferous altered wall rocks proximal to the gold bearing veins of these orogenic gold deposits we report here major rare earth element ree and selected trace element compositions of tourmalines from these alteration zones at hutti and hira buddini and from spatially associated volcaniclastic rocks at uti in order to compare and evaluate possible fluid sources related to tourmaline precipitation and gold mineralization tourmalines at hutti occur as tourmaline calcite microveins within proximal alteration zones and as disseminated grains along the biotite chlorite defined mylonitic foliation these tourmalines belong to the dravite oxydravite group with an evolutionary trend towards magnesio foitite and commonly are mg rich up to 2 06 apfu with low na 0 61 apfu and up to 53 x site vacancies characteristics are low abundances of total ree 0 25 0 67 chondrite and a flat trend with minor hree enrichment accompanied by strong positive eu anomalies at hira buddini tourmalines of the oxydravite povondraite series replace amphiboles and hydrothermal biotite based on textural and chemical characteristics three generations of tourmalines are present at hira buddini earliest type i tourmaline has moderate fe content up to 1 46 apfu high na average 0 80 apfu and moderate x site vacancies up to 22 type ii tends to be relatively enriched in fe up to 2 08 apfu have similar na contents average 0 79 apfu and low x site vacancies up to 8 these tourmalines contain higher total ree 0 93 2 23 chondrite and display a flat trend with slight middle rare earth element mree depletion accompanied by a small positive eu anomaly the latest tourmalines type iii are fe poor up to 1 52 apfu and na poor average 0 67 apfu with relatively high x site vacancies up to 21 this tourmaline type has relatively low total rees 0 21 1 05 chondrite and similar abundance patterns to those of hutti tourmalines accompanied by large positive eu anomalies similarity in tourmaline compositions with evolutionary trends in compositional space from different textural associations suggests that a single low salinity and reduced metamorphogenic fluid with inherently low ree was responsible for proximal alteration and gold mineralization at hutti the type i and type ii tourmalines from hira buddini display oxydravite povondraite trends with compositional overlap that suggests fluid mixing at a paragenetically early stage the early hydrothermal fluid was more saline oxidizing and likely had a granite derived component with high ree contents a later evolved relatively low salinity and reduced fluid is recorded by the last generation type iii tourmalines at hira buddini the tourmalines from uti metapelites are characterized by dravitic composition low na contents high x site vacancies 31 47 and an evolutionary trend toward magnesio foitite these tourmalines have higher ree contents 1 16 2 08 chondrite lree enriched patterns together with large positive eu anomalies and low concentrations of most trace elements all features that suggest a metamorphic origin

intensity and structure changes during hurricane eyewall replacement cycles abstracta flight level aircraft dataset consisting of 79 atlantic basin hurricanes from 1977 to 2007 was used to develop an unprecedented climatology of inner core intensity and structure changes associated with eyewall replacement cycles ercs during an erc the inner core structure was found to undergo dramatic changes that result in an intensity oscillation and rapid broadening of the wind field concentrated temporal sampling by reconnaissance aircraft in 14 of the 79 hurricanes captured virtually the entire evolution of 24 erc events the analysis of this large dataset extends the phenomenological paradigm of ercs described in previous observational case studies by identifying and exploring three distinct phases of ercs intensification weakening and reintensification in general hurricanes intensify sometimes rapidly when outer wind maxima are first encountered by aircraft the mean locations of the inner and outer wind maximum at the start of an erc are 35 and 106 km from storm center respe

hydrothermal gold mineralization at the hira buddini gold mine india constraints on fluid evolution and fluid sources from boron isotopic compositions of tourmaline we determined the boron isotope and chemical compositions of tourmaline from the hira buddini gold deposit within the archean hutti maski greenstone belt in southern india to investigate the evolution of the hydrothermal system and to constrain its fluid sources tourmaline is a minor but widespread constituent in the inner and distal alteration zones of metabasaltic and metadacite host rocks associated with the hydrothermal gold mineralization the hira buddini tourmaline belongs to the dravite schorl series with variations in al fe fe mg ca ti and cr contents that can be related to their host lithology the total range of 11b values determined is extreme from 13 3 to 9 0 but 95 of the values are between 4 and 9 the boron isotope compositions of metabasalt hosted tourmaline show a bimodal distribution with peak 11b values at about 2 and 6 the wide range and bimodal distribution of boron isotope ratios in tourmaline require an origin from at least two isotopically distinct fluid sources which entered the hydrothermal system separately and were subsequently mixed the estimated 11b values of the hydrothermal fluids based on the peak tourmaline compositions and a mineralization temperature of 550 c are around 1 and 10 the isotopically lighter of the two fluids is consistent with boron released by metamorphic devolatilization reactions from the greenstone lithologies whereas the 11b rich fluid is attributed to degassing of i type granitic magmas that intruded the greenstone sequence providing heat and fluids to the hydrothermal system

transport of10be and9be in the ocean beryllium isotopes 10be and9be have been measured in suspended particles of 1 mm size collected by mid water sediment traps deployed in the eastern pacific at manop sites h 6 32 n 92 50 w water depth 3600 m and m 8 50 n 104 00 w 3100 m for comparison surface sediments from box cores taken from the two sites were also studied the concentrations of10be and9be in sediment trap particles are about an order of magnitude smaller than those in the bottom sediments which contain about 8 109 and 6 1016 atoms g 1 of10be and9be respectively the sediment trap samples collected from 50 m off the bottom showed significant 26 63 contributions from resuspended bottom sediments the10be 9be ratio in trap samples varies from 3 to 20 10 8 the variation may partly result from varied proportion of authigenic detrital material the fluxes of both isotopes exhibit a very strong seasonality the fluxes of10be into the traps at about 1500 m are estimated as 9 105 and 4 105 atoms cm 2 a 1 at sites h and m respectively these values are to be compared with the fluxes into the sediments of 4 5 105 atoms cm 2 a 1 at both locations good correlations exist between10be 9be and27al indicating that the primary carrier phase s for the beryllium isotopes in the water column may be aluminosilicates

cosmogenic nuclide dating of sahelanthropus tchadensis and australopithecus bahrelghazali mio pliocene hominids from chad ages were determined at two hominid localities from the chad basin in the djurab desert northern chad in the koro toro fossiliferous area kt 12 locality 16 00 n 18 53 e was the site of discovery of australopithecus bahrelghazali abel and in the toros menalla fossiliferous area tm 266 locality 16 15 n 17 29 e was the site of discovery of sahelanthropus tchadensis toumai at both localities the evolutive degree of the associated fossil mammal assemblages allowed a biochronological estimation of the hominid remains early pliocene 3 3 5 ma at kt 12 and late miocene 7 ma at tm 266 atmospheric 10be a cosmogenic nuclide was used to quasicontinuously date these sedimentary units the authigenic 10be 9be dating of a pelite relic within the sedimentary level containing abel yields an age of 3 58 0 27 ma that points to the contemporaneity of australopithecus bahrelghazali abel with australopithecus afarensis lucy the 28 10be 9be ages obtained within the anthracotheriid unit containing toumai bracket by absolute dating the age of sahelanthropus tchadensis to lie between 6 8 and 7 2 ma this chronological constraint is an important cornerstone both for establishing the earliest stages of hominid evolution and for new calibrations of the molecular clock

application of the authigenic 10be 9be dating method to continental sediments reconstruction of the mio pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern chad basin the concentrations of atmospheric cosmogenic 10be normalized to the solubilized fraction of its stable isotope 9be have been measured in the authigenic phase leached from silicated continental sediments deposited since the upper miocene in the northern chad basin this method is validated by the systematic congruence with the biochronological estimations based on the fossil mammal evolutive degree of faunal assemblages the fifty five authigenic 10be 9be ages obtained along 12 logs distributed along two west east cross sections that encompass best representative mio pliocene outcrops including paleontological sites show a systematic stratigraphic decrease when considering all studied sedimentary facies extending from the pleistocene up to 8 ma and allow performing geologic correlations otherwise impossible in the studied area the resulting global sequence evidences and temporally specifies the succession of the main paleoenvironments that have developed in this region since the miocene under the special conditions encountered in the northern chad basin this study demonstrates that the authigenic 10be 9be ratio may be used as a dating tool of continental sedimentary deposits from 1 to 8 ma the half life of 10be theoretically allowing dating up to 14 ma it may have fundamental implications on important field research such as paleoclimatology and through the dating of fossiliferous deposits in paleontology and paleoanthropology

constancy of oceanic deposition of 10 be as recorded in manganese crusts recent developments in the use of nuclear accelerators as high energy mass spectrometers1 2 has renewed interest in the study of cosmogenic 10be half life 1 5 myr as a geophysical time tracer the accelerator techniques enable us to measure 10be with a sensitivity of 107 atoms or less the potential age dating span with 10be is extended back to at least 15 myr bp providing that the 10be production and deposition rates remain constant or nearly constant over that time period a knowledge of the long term constancy in the 10be deposition rate is thus very important we report here the first detailed measurements of 10be and 9be in two ferromanganese oxide crusts from the sea floor of the equatorial atlantic sample no k 9 21 and the north pacific schw 1d each representing 10 myr of accumulation history we have found in these crusts that the deposition of 10be and 10be 9be during the past 7 9 myr has been constant averaged over time intervals of 1 myr the variation is within 6 before that time both crusts show similar significant deviations the 7 9 myr demarcation may be related to the reported late miocene global abyssal circulation change in the ocean3

fluctuation of biogenic and abiogenic sedimentation on the shatsky rise in the western north pacific during the late quaternary abstract sedimentation of biogenic and abiogenic components was studied in cores ngc108 36 36 85 n 158 20 90 e water depth 3390 m and s2612 32 19 84 n 157 51 00 e water depth of 2612 m from the shatsky rise to understand fluctuations in primary productivity and abiogenic sedimentation in the mid latitude of the western north pacific during the late quaternary the mean c organic n atomic ratio of 6 0 7 8 in both cores indicates that organic matter is mainly marine in origin organic carbon is positively correlated with biogenic opal in core ngc108 in contrast to a weak correlation in core s2612 although the maxima of paleoproductivity estimates in both cores generally occur during glacial times the paleoproductivity estimates biogenic opal carbonate ratios and the c organic c carbonate ratios have always been higher in core ngc108 than in core s2612 during the last 180 kyr suggesting that the surface water at site ngc108 could have been influenced more by subarctic water mass than at site s2612 however the opal carbonate ratio in core s2612 remains fairly constant relative to that in core ngc108 which might mean that the transition zone between subarctic and central water was narrower in latitude in at the oxygen isotope stage ois 2 3 boundary ois 4 and ois 6 sedimentation of 13 inorganic elements has been measured in both cores these elements are classified into four groups based on correlation between each element in content 1 terrigenous components al ti fe 2 biogenic calcareous material ca sr 3 biogenic scavenged elements mg zn cr be and 4 the other elements mn ba cu ni the terrigenous mass accumulation rates were elevated in ois 2 3 and 4 and late ois 6 in core ngc108 while they were higher in early ois 1 ois 2 4 and 6 in core s2612 mno 2 and ba might be redistributed during the sub surface reduced condition especially precipitation of particle reactive be which could be accelerated by both enhanced terrigenous input and biogenic vertical transport has fluctuated largely in response to climatic change because of its short residence time on the order of the oceanic mixing time

boron isotopic composition of tourmaline from massive sulfide deposits and tourmalinites boron isotope ratios 11b 10b have been measured on 60 tourmaline separates from over 40 massive sulfide deposits and tourmalinites from a variety of geologic and tectonic settings the coverage of these localities is global 5 continents and includes the giant ore bodies at kidd creek and sullivan canada broken hill australia and ducktown usa overall the tourmalines display a wide range in 11b values from 22 8 to 18 3 possible controls over the boron isotopic composition of the tourmalines include 1 composition of the boron source 2 regional metamorphism 3 water rock ratios 4 seawater entrainment 5 temperature of formation and 6 secular variations in seawater 11b the most significant control appears to be the composition of the boron source particularly the nature of footwall lithologies variations in water rock ratios and seawater entrainment are of secondary importance the boron isotope values seem especially sensitive to the presence of evaporites marine and non marine and carbonates in source rocks to the massive sulfide deposits and tourmalinites

10be dating of large manganese nodules from world oceans the results of 10be and 9be measurements in several sections of ten large manganese nodules are presented along with u and th isotope data on five of them the 10be and 10be 9be methods yield growth rates covering a period of 5 10 ma which are in excellent agreement with each other in three cases these rates are also in very good agreement with those derived from the 230th methods whereas in the other two the 230th based rates are faster by over a factor of two based on the discrepancy between the inventory of 10be as well as 230th in nodules and the overhead seawater column it is calculated that the former scavenge their be and th isotopes from 2 900 m of the overhead water column the deduced 9be concentrations of ocean water based on its 10be contents and the 10be 9be ratios of nodule surfaces are found to be in good agreement with the direct 9be measurements of seawater implying that 9be in nodules like10be is mostly authigenic

concentric eye walls secondary wind maxima and the evolution of the hurricane vortex abstract research aircraft observations in recent hurricanes support the model of shapiro and willoughby 1982 for the tropical cyclone s response to circularly symmetric convective heat sources convective rings in both nature and the numerical model the tangential wind commonly increases rapidly just inside the radius of maximum wind and decreases inside the eye near the central axis of the vortex thus both secondary outer wind maxima and eyewall wind maxima often contract as they intensify this response is independent of the horizontal spatial scale of the maximum an outer maximum is frequently observed to constrict about a pre existing eye and replace it this chain of events often coincides with a weakening or at least a pause in intensification of the vortex as a whole the concentric eye phenomenon is a common but by no means universal feature of tropical cyclones it is most frequently observed in intense highly symmetric systems

pressure temperature and fluid conditions during emerald precipitation southeastern yukon canada fluid inclusion and stable isotope evidence abstract the crown emerald veins are somewhat enigmatic displaying characteristics that are common to emerald deposits of tectonic hydrothermal origin and of igneous origin the veins cut the fire lake mafic meta volcanic rocks occurring within 600 m of an outcrop of cretaceous s type granite field work and vein petrography are consistent with a polythermal origin for the veins the primary vein mineralogy is quartz and tourmaline with variable sized alteration haloes consisting of tourmaline quartz muscovite chlorite and emerald the veins weather a buff brown colour due to jarosite scheelite and minor lepidocrocite which were precipitated during the waning stages of vein formation microthermometic studies of primary fluid inclusions within emerald growth zones are consistent with emerald precipitation from h 2 o co 2 ch 4 n 2 h 2 s bearing saline brines the estimated fluid composition is approximately 0 9391 mol h 2 o 0 0473 mol co 2 0 0077 mol ch 4 and 0 0059 mol nacl 2 wt nacl eq fluid inclusion and stable isotope studies are consistent with vein formation in the temperature range 365 498 c with corresponding pressures along fluid inclusion isochore paths ranging from 700 to 2250 bars these data correlate with a very slow uplift rate for the region of 0 02 0 07 mm year emerald deposits are generally formed when geological conditions bring together cr v and be cr and v are presumed to have been derived locally from the mafic and ultramafic rocks during hydrothermal alteration the be is most likely derived from the nearby cretaceous granite intrusion

beryllium 10 in deep sea sediments a tracer for the earth s magnetic field intensity during the last 200 000 years abstract we present a new approach for the reconstruction of the earth s magnetic field intensity during the last 200 000 years based on 10 be in deep sea sediments a simple box model that is able to describe boundary scavenging of 10 be in the ocean is used to study the sensitivity of 10 be to changes of water circulation and or varying particle rain rates the model is applied to separate transport and production signal in single 10 be records vertical sediment accumulation rates are used as input values for the model calculations the calculated scavenging factors are applied to correct the 10 be records for boundary scavenging the model corrected 10 be based paleointensity record correlates well with other records from very different archives

chemical and boron isotope variations in tourmalines from an s type granite and its source rocks the erongo granite and tourmalinites in the damara belt namibia tourmaline is widespread in metapelites and pegmatites from the neoproterozoic damara belt which form the basement and potential source rocks of the cretaceous erongo granite this study traces the b isotope variations in tourmalines from the basement from the erongo granite and from its hydrothermal stage tourmalines from the basement are alkali deficient schorl dravites with b isotope ratios typical for continental crust 11b average 8 4 1 4 n 11 one sample at 13 n 2 virtually all tourmaline in the erongo granite occurs in distinctive tourmaline quartz orbicules this main stage tourmaline is alkali deficient schorl 20 30 x site vacancy fe fe mg 0 8 1 with uniform b isotope compositions 11b 8 7 1 5 n 49 that are indistinguishable from the basement average suggesting that boron was derived from anatexis of the local basement rocks with no significant shift in isotopic composition secondary hydrothermal tourmaline in the granite has a bimodal b isotope distribution with one peak at about 9 like the main stage tourmaline and a second at 2 we propose that the tourmaline rich orbicules formed late in the crystallization history from an immiscible na b fe rich hydrous melt the massive precipitation of orbicular tourmaline nearly exhausted the melt in boron and the shift of 11b to 2 in secondary tourmaline can be explained by rayleigh fractionation after about 90 b depletion in the residual fluid

10be spikes in plio pleistocene cyclothems wanganui basin new zealand identification of the local flooding surface lfs marine shelf sediments of the wanganui basin castlecliff section spanning oxygen isotope stages 21 17 ca 920 680 ka contain spikes of enriched 10be concentrations and enhanced 10be 9be ratios up to 10 background values the 10be spikes do not coincide precisely with peaks in carbonate content and grainsize or with changes in bulk rock chemical composition rather they appear in the sequence a little above the base of each cyclothem at the presumed location of the local flooding surface lfs they therefore originated in response to seafloor sediment starvation during transgression and not from ice sheet melting biogenic scavenging or geomagnetic intensity changes as has been suggested previously for 10be spikes in some deep sea or continental margin sequences

boron isotope systematics of tourmaline formation in the sullivan pb zn ag deposit british columbia canada abstract we report here the results of 54 boron isotope analyses of tourmaline associated with the giant sullivan pb zn ag deposit in southeastern british columbia canada the 11 b values range from 11 1 to 2 9 which is almost as great as the range found worldwide in tourmalines from 33 massive sulfide deposits and tourmalinites in dominantly clastic metasedimentary terranes the major control on the overall 11 b values of the sullivan tourmalinites is the boron source potential controls over the large range of the data also include 1 differences in formation temperatures of the tourmalinites 2 different stages of tourmaline formation 3 variations in the proportions of dissolved boron incorporated into the tourmaline rayleigh fractionation 4 seawater entrainment and 5 post depositional metamorphism the boron isotope data at sullivan are consistent with boron derivation from leaching of footwall clastic sediments however the great abundance of tourmaline in the sullivan deposit suggests that the local clastic sediments were not the sole source of boron and we argue that non marine evaporites buried deep below the orebody are the most viable source of this additional boron it is likely that some of the variation in tourmaline 11 b values reflect mixing of boron from these two sources comparison of the potential effects of these controls with geologic and other geochemical evidence suggests that major causes for the wide range of 11 b values measured at sullivan are seawater entrainment and rayleigh fractionation although in places post depositional alteration and thermal metamorphism were important in determining 11 b values of some of the recrystallized tourmalinites

elemental and b o h isotopic compositions of tourmaline and associated minerals in biotite muscovite granite of mashhad ne iran constraints on tourmaline genesis and element partitioning abstract abundant tourmaline occurs in late triassic biotite muscovite granites of mashhad ne iran with several distinct morphologies including tourmaline nodules in granite pegmatitic tourmalines aplitic tourmalines and vein related tourmalines quartz tourmaline vein tourmaline rich vein and radial tourmalines pegmatitic and aplitic tourmalines are compositionally fe rich schorl and the nodule radial and vein tourmalines are mg rich schorl the tourmalines have generally low abundances for most trace elements except for sr ga li be sn pb and some transition elements tourmalines have low ree abundances and are enriched in lree and depleted in hree mostly below detection limits with positive eu anomalies the concentration of several trace elements e g pb be sn ga sr pb and ree correlates well with the major element composition of the tourmalines e g mg mg mg fe vacancy x site vacancy na and na na ca trace element data of coexisting minerals with tourmaline indicate that the oligoclase and albite show the most preference in sr pb and eu and lrees biotite readily incorporates rb ba zn li cs and nb k feldspar has high contents of rb ba sr and pb and garnet incorporates hrees and y during magma differentiation the b o h isotopic compositions for all tourmalines are consistent with an s type granite source that was derived from partial melting of the continental crust the pegmatitic and aplitic tourmalines with fe rich schorl composition indicate magmatic conditions and the radial vein and nodule tourmalines with mg rich schorl composition formed during the transition from magmatic to hydrothermal conditions due to the internal evolution of the granitic magma

assessment of tourmaline compositions as an indicator of emerald mineralization at the tsa da glisza prospect yukon territory canada tourmaline is ubiquitous at the tsa da glisza emerald prospect yukon territory occurring as porphyroblasts in greenschistfacies metavolcanic and ultramafic rocks and as crystals in granites aplites and quartz tourmaline veins the principal occurrence of emerald is along contacts between the quartz tourmaline veins and mafic country rocks but it also occurs in the aplites we assess the potential of using tourmaline compositions as a guide to emerald mineralization at tsa da glisza based on major element trace element li be sc cr v mn ni co cu zn as rb sr y zr nb cd mo sn sb cs ba ta w bi pb th and u ree la ce pr nd sm eu yb lu and boron isotope data the tourmaline compositions encompass na fe schorl na mg dravite and ca mg uvite and show a strong dependence on host rock chemistry tourmalines closely associated with emeralds intergrown in same hand specimen are slightly more iron rich dravites compared with those from schists and alteration zones lacking emerald binary and ternary plots of major and trace element concentrations show that emerald associated tourmalines occupy restricted ranges of composition albeit considerably overlapping those not associated with emerald trace element concentrations in tourmaline associated with emerald mineralization include 20 to 40 ppm co 50 ppm ni 0 5 ppm la 0 5 ppm y 100 to 200 ppm li and 300 to 600 ppm zn boron isotope 11b values range from 15 6 to 4 2 per mil for all tourmalines n 80 low values are most common and are consistent with a dominantly granitic source of boron higher isotope ratios 8 are confined to tourmalines from country rocks and quartz veins suggesting a contribution of isotopically heavy b from the maficultramafic series the three emerald related samples have a restricted intermediate range of 10 3 to 7 9 per mil multivariate cluster analysis defines two populations of tourmalines corresponding to host rock type one cluster includes tourmaline from country rocks and quartz tourmaline veins and the other is dominated by samples from granites and aplites the latter cluster also includes all tourmalines associated with emeralds with trace element concentrations and boron isotope values as input variables one stepwise discriminant function analysis model produces a 91 percent correct classification matrix and an 88 percent correct jackknifed classification matrix this result suggests that tourmaline has potential as an indicator mineral at the tsa da glisza prospect and possibly also in the exploration for emeralds elsewhere

tourmaline composition as a guide to mineral exploration a reconnaissance study from nova scotia using discriminant function analysis tourmaline has an extensive range of solid solution that can potentially reflect the nature of its coexisting phases including some minerals of economic interest in this study tourmaline compositions are considered in the framework of two hypothetical classes of mineral deposits to evaluate the use of tourmaline chemistry to assess economic potential tourmalines from 27 known mineralized and barren localities in nova scotia were analyzed by electron microprobe for their major elements and by inductively coupled plasma mass spectrometry for their boron isotope compositions linear discriminant function analysis of these data on a two group mineralized and barren basis correctly classified 85 to 89 percent of the tourmaline samples similarly linear discriminant function analysis on a three group nongranite mineralized granite related mineralized granite related barren basis correctly classified 72 to 85 percent of the tourmaline samples quadratic discriminant function analysis resulted in even better discrimination these preliminary results suggest that this type of geochemical statistical approach is promising for mineral exploration

particulate fluxes of 230th 231pa and 10be in the northeastern pacific ocean abstract measurements of 230th 231pa and 10be in sediment trap samples and holocene sediments collected along a transect in the northeastern pacific indicate that the removal of these nuclides from the ocean is greatly influenced by boundary scavenging more than 35 of the 230th at least 70 of the 231pa and as much as 85 of the 10be fluxes collected by sediment traps at a nearshore site located 120 km off shore are supplied by lateral transport of the dissolved nuclides from the open ocean these findings are consistent with the hypothesis that boundary scavenging is proportional to the oceanic residence times of the nuclides 10 40 y for 230th 100 y for 231 pa and 1000 y for 10be results of this study indicate that particle flux is a principal factor influencing scavenging of 230th 231pa and 10be from the water column the marine geochemistry of 10be in ocean margins is fundamentally different from that in the open ocean scavenging of 10be occurs throughout the water column at the margin area in this study in contrast to the pattern of 10be being removed only in the surface waters and then remineralized at depth in the open ocean aluminosilicate may be a major phase removing 10be from the water column in the open ocean but not at ocean margins nuclide accumulation rates in the underlying holocene sediments are all higher than the corresponding fluxes collected by sediment traps several possibilities that could account for this observation include downslope sediment transport deployment of the traps during a period when the particle flux was not representative of long term average conditions and scavenging of the nuclides from near bottom waters the high accumulation rate of authigenic mn in some holocene sediments which can be attributed to redox cycling of mn may have caused near bottom scavenging of 230th and 231pa as well as certain other trace elements such as ba cu and zn

10be and th isotopes in manganese nodules and adjacent sediments nodule growth histories and nuclide behavior abstract the concentration profiles of 9 be 10 be 230 th 232 th 231 pa via 227 th and 238 u have been measured in three manganese nodules one each from the north pacific a47 16 4 the south pacific tf 5 and the indian ocean r v vitiaz in addition the 10 be concentration in deep water from the geosecs reoccupation station 500 of the north pacific and in cores raised from the manganese nodule field in the north pacific have been measured the 10 be concentration in nodule and seawater samples was measured by the accelerator masss spectrometric technique employing the yale tandem van de graaff accelerator the concentrations of 10 be 230 th exc and 231 pa exc and ratios of 10 be 9 be and 230 th exc 232 th all decrease with depth in the nodules this decrease interpreted in terms of nodule growth yields average growth rates of a few millimeters per million years for the nodules the growth rates of the nodules exhibit temporal variations both on short time 50 000 years and long time several million years scales of the three nodules studied only in tf 5 is the short term average growth rate based on 230 th exc in the top 0 0 5 mm the same as the long term average rate based on be isotope data for the 0 5 17 mm interval for the other two nodules the recent average growth rates based on 230 th exc data differ significantly from the long term average growth rates based on be isotopes in a47 16 4 the 10 be based rate is less than the 230 th exc rate and in r v vitiaz the 10 be based rate is greater than the 230 th exc rate this observation coupled with measurable changes in growth rates even during the past few hundred thousand years suggests but does not prove that the discordant growth rates deduced from 230 th exc and 10 be profiles document changes in nodule growth rate with time rather than mixing effects on 230 th exc profiles the 10 be concentration in the geosecs north pacific deep water is 6100 1200 atoms g this value coupled with the average surface 10 be 9 be ratio of north pacific nodules predicts a 9 be concentration within the limits of measured values the inventory of 10 be and 230 th exc in the nodules is only 10 of the total the remaining being in sediments the 10 be concentrations in the upper portions of two adjacent cores studied are nearly the same but the deposition fluxes of both 10 be and 230 th based on 230 th dating vary by a factor of two this difference is attributable to local redistribution of sediment at the time of deposition prior to accumulation

26al 10be and u th isotopes in blake outer ridge sediments implications for past changes in boundary scavenging we have investigated the distributions of 26 al 10 be u th isotopes and stable 27 al and 9 be in core ch88 11p 30 40pn 74 41pw 3337 m from the blake outer ridge bor in the western north atlantic an area that is characterized by high terrigenous input results show authigenic 26 al 27 al of 6 2 8u10 314 atom atom authigenic 10 be 9 be of 0 5 2 6u10 38 atom atom 6 0 2 1 8u10 6 atoms g of 26 al and 5 3 15 1u10 8 atoms g of 10 be in the core over the last glacial interglacial cycle these values as well as total 230 thex 232 th and 10 be 9 be ratios were all at their minima during the last glacial maximum lgm reflecting intensified terrestrial influx to the area aluminosilicate material clays in this influx preferentially scavenged 230 th over the two other particle reactive nuclides 26 al and 10 be such that their boundary scavenging during lgm followed the order 230 ths 10 bes 26 al as opposed to 10 bev 230 ths 26 al in the holocene they appear at variance with the order 10 bes 26 alw 230 th as would be predicted from the relative particle reactivities of the three species these scavenging characteristics point to 10 be 26 al as a potentially more suitable proxy for paleoproductivity than 10 be 230 thex mass balance considerations for 26 al and 10 be show a five fold lgm to holocene increase in deep water circulation in the study area with little change in ocean productivity except during the deglaciation when it increased noticeably fl 2001 elsevier science b v all rights reserved

tourmaline as a recorder of contrasting boron source and potential tin mineralization in the mopanshan pluton from inner mongolia northeastern china abstract abundant tourmaline occurs in the mopanshan pluton in inner mongolia of ne china and can be classified by its occurrence into four types nodular tourmalines nd type pegmatite pocket tourmalines pp type stockwork tourmalines sw type and vein tourmalines vt type all these tourmalines belong to the alkali group and are dravite schorl petrography and major elements data suggest that the nd and pp type tourmalines crystallized during the transition from late magmatic to early hydrothermal evolution of granite with all the components derived from the magma petrography and trace elements especially sr v cr ni ti data suggest that the sw and vt type tourmalines may form by the mixing of magmatic and country rocks components in the post magmatic hydrothermal environment due to the similar 11b of the sw type with the nd and pp type tourmalines variation

on the distribution of subsidence in the hurricane eye two hurricane eye features that have yet to be adequately explained are the clear air moat that forms at the outer edge of the eye and the hub cloud that forms near the circulation centre to investigate whether these features can be explained by the spatial distribution of the subsidence field we have derived an analytical solution of the sawyer eliassen transverse circulation equation for a three region approximation with an unforced central eye region of intermediate or high inertial stability a diabatically forced eyewall region of high inertial stability and an unforced far field of low inertial stability this analytical solution isolates the conditions under which the subsidence is concentrated near the edge of the eye the crucial parameter is the dimensionless dynamical radius of the eye defined as the physical radius of the eye divided by the characteristic rossby length in the eye when this dimensionless dynamical radius is less than 0 6 there is less than 10 horizontal variation in the subsidence rate across the eye when it is greater than 1 8 the subsidence rate at the edge of the eye is more than twice as strong as at the centre of the eye when subsidence is concentrated at the edge of the eye the largest temperature anomalies occur near there rather than at the vortex centre this warm ring structure as opposed to a warm core structure is often observed in the lower troposphere of intense hurricanes copyright 2007 royal meteorological society

last glacial to post glacial 10be fluctuations in a sediment core from the academician ridge lake baikal 10be concentrations sediment composition and sediment accumulation rates were determined in a sediment core from the academician ridge of lake baikal the 10be concentrations vary from 5 07 108 atoms g in the last glacial section to 11 25 108 atoms g in the section representing the post glacial climate stage 10be fluxes on the other hand increase toward the last glacial stage coinciding with an increase of the sediment accumulation rate these facts imply that climate related sedimentation is related to both flux and concentration of the nuclide in the sediment core during the last glacial stage arid conditions in the lake s watershed caused a marked increase in flux of clay particles with low 10be content to the lake resulting in an increased flux but lowered concentration of 10be in the sediments it is suggested that the 10be record of the bottom sediments of lake baikal can be used as a proxy indicator of climate change in central asia

late magmatic immiscibility during batholith formation assessment of b isotopes and trace elements in tourmaline from the land s end granite sw england quartz tourmaline orbicules are unevenly distributed in the roof segment of the land s end granite sw england this study shows that the orbicules formed from an immiscible hydrous borosilicate melt produced during the late stages of crystallization and differentiates tourmaline formed by dominantly magmatic and dominantly hydrothermal processes trace elements and boron isotope fractionation can be tracked in tourmaline and create a timeline for crystallization tourmaline from the granite matrix has higher v cr and mg content and is isotopically heavier than the later crystallizing inner orbicule tourmaline overgrowths of blue tourmaline occurring together with quartz showing hydrothermal cathodoluminescence textures crystallized from an aqueous fluid during the very last crystallization and are significantly higher in sr and sn and isotopically heavier tourmaline associated with sn mineralization is also high in sr and sn but has boron isotopic compositions close to that of the magmatic tourmaline and is not formed by the same fluids responsible for the blue overgrowths the ore forming fluids precipitating tourmaline and cassiterite are likely derived from the same magma source as the granite but exsolved deeper in the magma chamber and at a later stage than orbicule formation tourmaline from massive quartz tourmaline rocks is concentrically zoned with major and trace element compositions indicating crystallization from a similar melt as for the orbicules but shows a more evolved signature

similar glacial and interglacial export bioproductivity in the atlantic sector of the southern ocean multiproxy evidence and implications for glacial atmospheric co2 we present time series of export productivity proxy data including 230thex normalized deposition rates rain rates of 10be dissolution corrected biogenic ba and biogenic opal as well as authigenic u concentrations which are complemented by rain rates of total detrital fe and sea ice indicating diatom abundances from five sediment cores across the atlantic sector of the southern ocean covering the past 150 000 years the results suggest that 10be rain rates and authigenic u concentration cannot serve as quantitative paleoproductivity proxies because they have also been influenced by detrital particle fluxes in the case of 10be and bulk sedimentation rates sediment focussing and deep water oxygenation in the case of u the combined results of the remaining productivity proxies of this study rain rates of biogenic opal and biogenic ba in those sections without authigenic u and other previously published proxy data from the southern ocean 231pa 230th and nitrogen isotopes suggest that a combination of sea ice cover shallow remineralization depth and stratification of the glacial water column south of the present position of the antarctic polar front and possibly fe fertilization north of it have been the main controlling factors of export paleoproductivity in the southern ocean over the last 150 000 years an overall glacial increase of export paleoproductivity is not supported by the data implying that bioproductivity variations in the southern ocean are unlikely to have contributed to the major glacial atmospheric co2 drawdown observed in ice cores