gas and aerosol emissions from lascar volcano northern chile insights into the origin of gases and their links with the volcanic activity abstract this study focuses on the chemical compositions of volcanic gases and aerosols emitted by lascar volcano northern chile the sustained volcanic plume was sampled in april 2009 april 2011 and november 2012 through filter packs and analyzed for major gaseous species so 2 hcl and hf and trace elements during fieldwork so 2 flux measurements were also performed by uv spectrometry doas the lascar volcano is a significant and sustained emitter of so 2 between 150 and 940 t d hcl between 170 t d and 210 t d and hf up to 100 t d combining the so 2 normalized trace element concentrations and the so 2 emission rates we evaluate that the quiescent degassing of lascar is an important local source of trace metals to the atmosphere with contributions to global volcanic fluxes generally less than 2 our data were used to infer the origin of the gas emitted at lascar two major degassing sources were identified a deep magmatic reservoir and a shallow hydrothermal system the variable interaction between these two sources is the most likely scenario for explaining the compositional ranges in acid gases but also in a volatile and fluid mobile trace element such as b these variations are related to changes in volcanic activity an extensive interaction between the hot ascending magmatic gases and the shallow aquifer occurred in 2009 possibly due to a long period of quiescence before magmatic activity renewed in 2011 and 2012 our study highlights therefore that filter pack measurements may be used to study changes in subsurface processes that probably play a key role in triggering volcanic eruptions

recent emerged reef terraces of the yenkahe resurgent block tanna vanuatu implications for volcanic landslide and tsunami hazards emerged reef terraces record the extraordinarily rapid holocene uplift rate of the fault bounded yenkahe resurgent block yrb located within a partially submerged quaternary caldera on tanna island vanuatu southwest pacific the presently active volcano yasur is located at the western end of the yrb episodic uplift of the yrb is probably associated with the movement of magma below the yenkahe area a historically recorded uplift at port resolution bay in a d 1878 raised the shoreline 15 m this a d 1878 event was accompanied by a local earthquake and a tsunami that reached 12 m elevation coral samples from terraces at mean altitudes of 155 m and 15 m above present sea level yield 230 th 234 u dates of a d 1002 pm 10 and a d 1868 pm 4 respectively these ages imply a mean uplift of 156 mm yr for the yrb since a d 1002 until a d 1992 this volcanically related uplift occurs within the context of regional uplift of the southern new hebrides arc the late holocene uplift r

the use of 7 lioh impregnated filters for the collection of acidic gases and analysis by instrumental neutron activation analysis a simple system was designed using7lioh impregnated filters to collect acidic gases from ambient air and from highly concentrated volcanic plumes or gas streams these filters were developed for analysis using instrumental neutron activation analysis but other analytical techniques could be used as well the sampling system was designed to use a series of 1 3 m7lioh impregnated filters to collect high concentrations of acidic gases found in gas plumes of active volcanoes the filters are quantitative for so2 and the halide acids when sufficient base is present to neutralize the acidic species extremely high concentrations of so2 may not be collected quantitatively since so2 is a relatively weak lewis acid compared to the halide acids the acidic oxides of sb as and se were also collected quantitatively a particle filter preceded the impregnated filters in order to remove particles from the fumes this system has proven effective under difficult sampling conditions and since it is portable and light weight it could be used for many volcanological applications where high levels of acidic gaseous phase species need to be collected

gas emission strength and evolution of the molar ratio of bro so2 in the plume of nyiragongo in comparison to etna airborne and ground based differential optical absorption spectroscopy observations have been carried out at the volcano nyiragongo democratic republic of congo to measure so2 and bromine monoxide bro in the plume in march 2004 and june 2007 respectively additionally filter pack and multicomponent gas analyzer system multi gas measurements were carried out in june 2007 our measurements provide valuable information on the chemical composition of the volcanic plume emitted from the lava lake of nyiragongo the main interest of this study has been to investigate for the first time the bromine emission flux of nyiragongo a rift volcano and the bro formation in its volcanic plume measurement data and results from a numerical model of the evolution of bro in nyiragongo volcanic plume are compared with earlier studies of the volcanic plume of etna italy even though the bromine flux from nyiragongo 2 6t d is slightly greater than that from etna 1 9t d the bro so2 ratio maximum 7x10 5 is smaller than in the plume of etna maximum 2 1x10 4 a one dimensional photochemical model to investigate halogen chemistry in the volcanic plumes of etna and nyiragongo was initialized using data from multi gas and filter pack measurements model runs showed that the differences in the composition of volcanic volatiles led to a smaller fraction of total bromine being present as bro in the nyiragongo plume and to a smaller bro so2 ratio

emission of bromine and iodine from mount etna volcano 1 constraining fluxes of volcanic bromine and iodine to the atmosphere is important given the significant role these species play in ozone depletion however very few such measurements have been made hitherto such that global volcanic fluxes are poorly constrained here we extend the data set of volcanic br and i degassing by reporting the first measurements of bromine and iodine emissions from mount etna these data were obtained using filter packs and contemporaneous ultraviolet spectroscopic so2 flux measurements resulting in time averaged emission rates of 0 7 kt yr 1 and 0 01 kt yr 1 for br and i respectively from april to october 2004 from which we estimate global br and i fluxes of order 13 range 3 40 and 0 11 range 0 04 6 6 kt yr 1 observed changes in plume composition highlight the coherent geochemical behavior of hcl hf hbr and hi during magmatic degassing and strong fractionation of these species with respect to so2

sulphur dioxide particle and elemental emissions from mount etna italy during july 1987 sulphur dioxide emission rates were measured at mount etna italy during july 1987 while the volcano was undergoing relatively quiet activity the so2 flux averaged 930 587 1 mg d excluding 19 july when the flux was 3200 1730 1 mg d rising magma and or an influx of less degassed magma could explain the increased so2 flux the high so2 flux did not correlate with changes in observed volcanic activity this suggests that so2 monitoring may be useful as an indicator of shallow magmatic activity but not as a predictor of future eruptions of mount etna

composition resolved size distributions of volcanic aerosols in the mt etna plumes 1 particle size distributions for soluble and insoluble species in mt etna s summit plumes were measured across an extended size range 10 nm d 100 m using a combination of techniques automated scanning electron microscopy qemscan was used to chemically analyze many thousands of insoluble particles collected on pumped filters allowing the relationships between particle size shape and composition to be investigated the size distribution of fine silicate particles d 10 m was found to be lognormal consistent with formation by bursting of gas bubbles at the surface of the magma the compositions of fine silicate particles were found to vary between magmatic and nearly pure silica this is consistent with depletion of metal ions by reactions in the acidic environment of the gas plume and vent measurements of the size shape and composition of fine silicate particles may potentially offer insights into preemission synemission and postemission processes the mass flux of fine silicate particles from mt etna released during noneruptive volcanic degassing in 2004 and 2005 was estimated to be 7000 kg d 1 analysis of particles in the range 0 1 d m 100 by ion chromatography shows that there are persistent differences in the size distributions of sulfate aerosols between the two main summit plumes analysis of particles in the range 0 01 m d 0 1 m by scanning transmission electron microscopy stem shows that there are significant levels of nanoparticles in the mt etna plumes although their compositions remain uncertain

distribution of metals between particulate and gaseous forms in a volcanic plume in order to gain information on the distribution of metals between particles and gaseous forms in the plume of kilauea volcano a filter designed to collect metals associated with particles was followed in series by two other collectors intended to trap metals present in gaseous atomic molecular or complexed form first an acid bubbler bath and then a cold trap of the six metals measured all of the in tl and bi and almost all of the cd pb and cu were found on the filter none of any of the metals was detected in the acid bubbler bath masses equivalent to 0 3 of the amount of cd on the filter 0 4 of the amount of pb and 9 3 of the cu were measured in the cold trap the results indicate that all or nearly all of the six metals were partitioned to the particulate portion of the physical mixture of gases and particles that constitutes a volcanic plume but that there may be systematic differences between chalcophile metals in the ways they are partitioned between particulate and gaseous phases in a cooled plume and possibly differences in the acidity or other chemical properties of the molecular phases

metal transport in volcanic plumes a case study at white island and yasur volcanoes abstract we report new data on trace metal emissions at white island volcano 2015 2016 the first estimates from yasur volcano 2016 and a brief review of global volcanic metal fluxes bi cd tl se sb te and au are the most enriched metals and metalloids in the particulate phase of volcanic plumes observations of the particulate phase from the volcanic plumes of white island yasur and etna reveal abundant silicates and sulfates sulfuric acid and more interestingly zn oxide containing variable amounts of cu thermodynamic speciation calculations show chloride species to be very important in terms of gaseous metal transport complexation with sulfur in contrast appears significant only in s rich and cl poor gases at high 700 c temperature bromine despite being a minor component of volcanic gases is very efficient at complexing with metals and especially with cu pb bi zn and cr metal emission rates in the study period at white island are one to two orders of magnitude lower than reported previously with 6 10 kg d of cu as se and zn and

mobility and fluxes of major minor and trace metals during basalt weathering and groundwater transport at mt etna volcano sicily abstract the concentrations and fluxes of major minor and trace metals were determined in 53 samples of groundwaters from around mt etna in order to evaluate the conditions and extent of alkali basalt weathering by waters enriched in magma derived co 2 and the contribution of aqueous transport to the overall metal discharge of the volcano we show that gaseous input of magmatic volatile metals into the etnean aquifer is small or negligible being limited by cooling of the rising fluids basalt leaching by weakly acidic co 2 charged water is the overwhelming source of metals and appears to be more extensive in two sectors of the s sw paterno and e zafferana volcano flanks where out flowing groundwaters are the richest in metals and bicarbonate of magmatic origin thermodynamic modeling of the results allows to evaluate the relative mobility and chemical speciation of various elements during their partitioning between solid and liquid phases through the weathering process the facts that rock forming minerals and groundmass dissolve at different rates and secondary minerals are formed are taken into account at mt etna poorly mobile elements al th fe are preferentially retained in the solid residue of weathering while alkalis alkaline earth and oxo anion forming elements as se sb mo are more mobile and released to the aqueous system transition metals display an intermediate behavior and are strongly dependent on either the redox conditions mn cr v or solid surface related processes v zn cu the fluxes of metals discharged by the volcanic aquifer of etna range from 7 0 10 3 t a th to 7 3 10 4 t a na they are comparable in magnitude to the summit crater plume emissions for a series of elements na k ca mg u v li with lithophile affinity but are minor for volatile elements basalt weathering at mt etna also consumes about 2 1 10 5 t a of magma derived carbon dioxide equivalent to ca 7 of contemporaneous crater plume emissions the considerable transport of some metals in etna s aquifer reflects a particularly high chemical erosion rate evaluated at 2 3 10 5 t a enhanced by the initial acidity of magmatic co 2 rich groundwater

radioactive isotopes and trace elements in gaseous emissions from white island new zealand abstract measurements of the radioactivity of gases released by white island volcano show variations in 210 po concentrations with temperature in fumarolic gases and this is interpreted to be due to dilution of magmatic gases with vapours derived from an envelope of acid brines surrounding the vent system the degassing model derived for mount etna emissions is tested on white island magmatic gases the results are a short degassing time 2 days small degassing magma volume 5 10 6 m 3 and the following estimations of emanation coefficients pb 1 bi 2 7 cd 0 05 and cu 0 07 the initial content of s in the magma is estimated to be within the range 300 600 mg kg fluxes of trace metals kg day emitted by the volcano are estimated to be pb 125 bi 6 cu 300 and cd 9

selenium mobilization in soils due to volcanic derived acid rain an example from mt etna volcano sicily abstract the significant amounts of selenium se emitted by volcanoes may have important impact on human health due to the narrow range between nutrition requirement and toxic effects for living organisms upon se exposure although soils play a key role in determining the level in food and water and thereby human health little is known about the behaviour of se in volcanic soils in this work we evaluated the se release during rainwater soil interaction under controlled conditions using soils collected on the flanks of etna volcano and synthetic rain selenium concentrations in soil leachate solutions displayed a spatial distribution which cannot be explained by plume deposition total se soil concentrations or the presence of fe oxides instead al compounds and to a minor extent som were identified as the active phases controlling the selenate mobilization during interaction with sulphate containing rainwater this shows the importance of soils as reactive interfaces selenium is mobilized when volcanic derived acid rain interacts with poorly developed soils close to the crater this geogenic process might influence the chemical composition of groundwater and as a result human health

sulfur dioxide and particles in quiescent volcanic plumes from poas arenal and colima volcanos costa rica and mexico measurements of so2 emission rates and concentrations and of particle distribution size shape and composition were made in quiescent volcanic plumes emitted into the troposphere from poas and arenal volcanos costa rica and colima volcano mexico so2 emission rates were 700 180 metric tons per day t d for poas 210 30 t d for arenal and 320 50 t d for colima the concentrations of so2 calculated from the cospec lidar data were 5 380 ppb concentrations of so2 measured directly by flame photometry were 10 250 ppb particles collected in the plumes with a quartz crystal microbalance impactor were mostly less than 3 m in diameter and consisted of droplets of dilute sulfur bearing solutions and minor amounts of larger silicate particles coated with a sulfur bearing film or crust total particle concentrations were 4 7 g m3 for poas and 18 8 g m3 for colima comparison of concentrations of so2 in the plumes with gas samples collected at fumaroles on the ground suggests that the plumes are diluted by the atmosphere by factors of up to 105

kurile island arc volcanism structural and petrological aspects abstract this study discusses the structural and spatial characteristics of all known kurile island arc quaternary volcanoes which include 105 that are subaerial and 96 submarine volcanic activity in the island arc is distributed in two zones parallel to the kurile kamchatka deep sea trench the depth to the seismo focal zone in the frontal zone is 110 140 km and in the rear zone 160 190 km these frontal and rear volcanic zones show distinct variations in geochemical petrologic and mineralogic characteristics concentrations of k rb ba sr f be la ce nb zr u th ni and cr in similar volcanic rocks of the rear zone are typically more than twice as high as those in rocks of the frontal zone whereas concentrations of fe and v are half as high in the rear zone lavas as in those of the frontal zone variations in concentration along the strike of the arc are less pronounced the average 87 sr 86 sr ratios for the frontal and rear zones are northern kuriles 0 70322 and 0 70304 middle kuriles 0 70302 and 0 70295 and southern kuriles 0 70347 and 0 70306 respectively 143 nd 144nd values in lavas from the frontal and rear zones are 9 10 and 7 8 respectively be abundances in the kurile island arc lavas range from 2 2 10 6 at g to 7 9 10 6 at g no differences in 10 be abundances corresponding to the frontal and rear arc zones have been found acid and intermediate lavas from the volcanic front are characterized by a two pyroxene phenocryst association while similar lavas from the rear arc have amphibole and biotite bearing associations mineral compositions plagioclase pyroxene amphibole olivine in the two zones also show distinct differences plagioclase in the rear arc lavas is less calcic with higher k sr ba and lower fe than in the frontal lavas ferromagnesian minerals in the rear arc lavas contain less fe and more mg than in frontal lavas these data are used to develop a model for magma generation related to two levels of volatile separation from the subducting lithospheric plate

trace elements in the gas emissions from the erta ale volcano afar ethiopia high temperature 1084 c fumarolic emissions from a spatter cone at the erta ale north pit crater granted a rare opportunity to collect giggenbach bottles condensates and sublimates from the fumarolic gases of a rift plume volcano in the immediate proximity of degassing lava these results represent the highest temperature gases sampled directly for trace elements and the first high t fumarolic samples for a rift plume volcano sixty seven metals and metalloids were measured quantitatively by icp aes and icp ms in liquid gas condensates and solid sublimates the total amount of trace elements in the gas without si exceeded 170 ppm the ten most abundant elements transported in nonsilicate modes were na 61 ppm fe 41 ppm k 32 ppm br 12 4 ppm cd 3 0 ppm se 2 3 ppm cu 2 0 ppm zn 2 0 ppm te 1 7 ppm and as 1 2 ppm the gases contained 27 ppb re 1 5 ppb au 0 5 ppb pt and 0 27 ppb os rh and pd containing phases were observed in solid sublimates the only metal not detected by all analytical methods was ruthenium chalcophile elements cd cu zn se te as were transported primarily in the gaseous form alkali metals were emitted at least partially as liquid micron size sulfate droplets whereas alkali earths aluminum and ree had a high affinity to silicate aerosol in the form of basaltic microspheres the silicate aerosol content was evaluated at 59 ppm on average but varied within a 7 5 fold range during sampling because of the extremely high temperature refractory elements ca ba ta u and lree showed evidence of transport in the form of gaseous species the so2 flux in january 2011 was evaluated at 91 24 t d for the entire volcano including 31 t d from the north crater and 60 t d from the lava lake the daily output of trace elements from both erta ale craters without si was estimated at 53 kg d including 20 kg of na 13 5 kg of fe 10 5 kg of k 4 5 kg of chalcophile elements 9 g of re 0 5 g of au and 0 17 g of pt the trace element pattern of erta ale fumarolic gases do not possess any distinct geochemical specialization and resemble te patterns from fumarolic emissions of studied arc and plume volcanoes

rates of sulfur dioxide and particle emissions from white island volcano new zealand and an estimate of the total flux of major gaseous species airborne correlation spectrometry cospec was used to measure the rate of so2 emission at white island on three dates i e november 1983 1230 300 t d november 1984 320 120 t d and january 1985 350 150 t d t metric tons the lower emission rates are likely to reflect the long term emission rates whereas the november 1983 rate probably reflects conditions prior to the eruption of december 1983 the particle flux in the white island plume as determined with a quartz crystal microbalance cascade in november 1983 was 1 3 t d unusually low for volcanic plumes the observed plume particles as shown from scanning electron microscopy include halite native sulfur and silicates and are broadly similar to other volcanic plumes

volatilization transport and sublimation of metallic and non metallic elements in high temperature gases at merapi volcano indonesia abstract condensates silica tube sublimates and incrustations were sampled from 500 800 c fumaroles and lava samples were collected at merapi volcano indonesia in jan feb 1984 with respect to the magma merapi gases are enriched by factors greater than 105 in se re bi and cd 104 105 in au br in pb and w 103 104 in mo cl cs s sn and ag 102 103 in as zn f and rb and 1 102 in cu k na sb ni ga v fe mn and li the fumaroles are transporting more than 106 grams day g d of s cl and f 104 106 g d of al br zn fe k and mg 103 104 g d of pb as mo mn v w and sr and less than 103 g d of ni cu cr ga sb bi cd li co and u with decreasing temperature 800 500 c there were five sublimate zones found in silica tubes 1 cristobalite and magnetite first deposition of si fe and al 2 k ca sulfate acmite halite sylvite and pyrite maximum deposition of cl na k si s fe mo br al rb cs mn w p ca re ag au and co 3 aphthitalite k na sulfate sphalerite galena and cs k sulfate maximum deposition of zn bi cd se and in higher deposition of pb and sn 4 pb k chloride and na k fe sulfate maximum deposition of pb sn and cu and 5 zn cu and k pb sulfates maximum deposition of pb sn ti as and sb the incrustations surrounding the fumaroles are also chemically zoned bi cd pb w mo zn cu k na v fe and mn are concentrated most in or very close to the vent as expected with cooling atmospheric contamination and dispersion the highly volatile elements br cl as and sb are transported primarily away from high temperature vents ba si p al ca and cr are derived from wall rock reactions incomplete degassing of shallow magma at 915 c is the origin of most of the elements in the merapi volcanic gas although it is partly contaminated by particles or wall rock reactions the metals are transported predominantly as chloride species as the gas cools in the fumarolic environment it becomes saturated with sublimate phases that fractionate from the gas in the order of their equilibrium saturation temperatures devolatilization of a cooling batholith could transport enough acids and metals to a hydrothermal system to play a significant role in forming an ore deposit however sublimation from a high temperature high velocity carrier gas is not efficient enough to form a large ore deposit re se cd and bi could be used as supporting evidence for magmatic fluid transport in an ore deposit

size resolved chemical composition of aerosol emitted by erebus volcano antarctica 1 persistent open vent degassing of erebus volcano antarctica is a significant point source of gases and aerosol to the austral polar troposphere we report here on the chemical composition and size distribution of the erebus aerosol focusing on the water soluble fraction the aerosol was sampled at the rim of the active crater using a cascade impactor which collected and sized particles in 14 size bins from 10 to 0 01 m the soluble fraction of the erebus aerosol is distinct from other volcanic sources in several respects it is dominated by chloride bearing particles over 30 of total mass and has an unusually high cl so42 molar ratio of 3 5 coarse particles contribute little to the total mass of the soluble fraction elevated concentrations of f cl br and so42 are found in a narrow particle size fraction of 0 1 0 25 m the detection of particulate br reinforces our understanding of the potential for quiescent volcanic emissions to deplete tropospheric ozone the small aerosol size reflects the low atmospheric temperature and humidity which inhibit particle growth halide alkali metal salts na k cl f appear to be the most abundant species in the aerosol the concentration of pb is high compared to other volcanoes its exsolution may be promoted by the high abundance of halogens in erebus magma despite the previously reported high nox content in the plume we did not detect significant quantities of nitrate in the near vent aerosol our findings emphasize the potential regional significance of emissions from erebus for understanding the antarctic atmospheric composition and glaciochemical records

volcanic emissions of metals and halogens from white island new zealand and erebus volcano antarctica determined with chemical traps abstract volcanic emission rates of as sb pb hg se cl and f were determined at erebus volcano antarctica and white island new zealand using chemical traps the trace metal fluxes were determined by combining the species to s ratios in the solutions with so2 emission rates measured by correlation spectrometry at the two volcanoes at erebus volcano fluxes for the metals pb and hg were 2 0 10 4 and 8 1 10 6 kg s 11 respectively fluxes for cl f as sb and se 0 35 0 15 2 5 10 4 1 2 10 5 and 4 5 10 6 kg s 1 respectively agreed within error limits for values determined previously by the lioh impregnated filter method zreda gostynska g kyle p finnegan d prestbo k 1997 volcanic gas emissions from mount erebus and their impact on the antarctic environment journal of geophysical research 102 b7 15039 15055 demonstrating the utility of the chemical trap method a fall in the as s ratio from 7 10 4 in 1997 1999 to 3 10 4 in 2000 at erebus coincided with a change in the frequency and style of eruptive activity that may have been due to injection of magma into the system at white island chemical trap data indicated fluxes of cl 0 90 f 0 0079 pb 2 7 10 4 hg 1 1 10 5 as 1 3 10 4 sb 1 9 10 5 and se 1 5 10 5 kg s 1 samples collected 600 m downwind of the active crater were comparable to samples collected adjacent to the main gas vent showing that this method can still be used at some distance from a degassing vent

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

variations of cl f and s in mount etna s plume italy between 1992 and 1995 this study investigates data on the cl f and s concentrations of plume filter samples collected between 1992 and 1995 from mount etna the samples were collected during eruptive and noneruptive activity and show fairly constant cl f ratios but wide variation in the cl s ratios the determination of the cl f ratio between 5 and 14 allows an estimate of f degassing to be derived that ranges from 10 to 30 of the initial f content of the magma the variation in the cl s ratio fits an empirical two stage degassing model where gas with high cl s ratio is discharged during quiescient degassing and gas with low cl s ratios is discharged during eruptive degassing the typical permanent degassing occurs from a depth at which chlorine exsolution exceeds sulfur exsolution cl s 1 the opposite of this behavior is observed during eruptive periods when significant sulfur degassing occurs because magma degasses at near atmospheric pressure cl s 0 1 the cl s ratio in the plume characterizing the type of degassing has the potential to be a useful geochemical tool for monitoring the volcano

evolution of the taupo hikurangi subduction system abstract the present day taupo hikurangi subduction system is a southward extension of the tonga kermadec arc system into a sediment rich continental margin environment it consists of a shallow structural trench the hikurangi trough a 150 km wide imbricate thrust controlled accretionary borderland the continental slope shelf and coastal hills of eastern north island a frontal ridge the main greywacke ranges of north island and a volcanic arc and marginal basin the taupo volcanic zone structural elements become progressively more elevated and subduction more oblique towards the south the whole nne trending system is truncated at a largely strike slip transform boundary that extends along the southwestern part of the hikurangi trough and the hope fault of south island to the main alpine fault the volcanic arc is 200 270 km from the structural trench and comprises a nne trending chain of andesite dacite volcanoes extending along the eastern side of the taupo volcanic zone most of the andesites are olivine bearing and have been erupted within the last 50 000 years it is suggested the taupo hikurangi margin has evolved by rotation of accretionary elements from an original nw trending subduction system north of new zealand the older elements of the prism were associated with subduction of a re entrant of the pacific plate and perhaps the south fiji basin in mid tertiary times they subsequently became separated from their nw trending volcanic arc by dextral strike slip movement along curved faults east of the main greywacke ranges during the plio pleistocene oblique subduction and accretion intensified as the taupo hikurangi margin rotated into line with the nne trending kermadec system and a marginal basin was developed along a similar trend to form the taupo volcanic zone within the last 50 000 years olivine bearing andesite volcanism has commenced along the eastern side of the taupo volcanic zone

magma origin and evolution of white island whakaari volcano bay of plenty new zealand white island is an active composite stratovolcano in the bay of of the north island the pacific plate is being subducted plenty new zealand that comprises many small volume westwards under the australian plate at a rate of 50 mm yr to form the taupo hikurangi arc trench with phenocryst contents of 15 44 minor high mg basaltic system volcanic activity is now concentrated in the andesite explosive eruptions such as those of 1976 1992 may taupo volcanic zone tvz the youngest expression have occurred at intervals throughout the history of white island of 22 ma cenozoic continental margin arc volcanism in but are rarely preserved these alternate with major episodes of the north island of new zealand cole 1990 tvz andesite dacite lava extrusion the high mg magmas form by fig 1 inset is at the southern end of the 2800 km hydrous melting of mantle metasomatized by fluids from the tonga kermadec taupo volcanic arc system and the dehydrating slab at the slab mantle wedge interface that rise lau basin havre trough ngatoro basin back arc basin rapidly to shallow magma chambers 2 7 km where limited system southern havre trough and tvz are offset mixing and contamination occurs before eruption some of this sinistrally by 40 50 km and wright 1992 believes the magma remains in the magma chamber where it interacts with the offset to be accommodated by a series of dextrally oblique crystal mush from which it inherits phenocrysts to form so called and en echelon bookshelf faults the southwestern limit dirty lavas total phenocryst content of these lavas is correspondingly of this fault system is placed 20 km north of white higher as more magma is intruded into the chamber the heat flux island and has nw se orientation fig 1 inset will increase and melt fraction will eventually rise to the surface to tvz extends offshore into the bay of plenty as a form high silica andesite dacite magma clean lavas with fewer graben structure of 45 km width fig 1 bounded by the inherited phenocrysts similar multi magma chamber plumbing tauranga fault zone to the west and the white island systems with complex evolution involving fractionation and confault zone to the east wright 1992 the eastern side tamination probably occur in most andesite dacite arc volcanoes of tvz coincides with the current active volcanic front and a broadly linear alignment of andesitic volcanoes extends from ruapehu in the southwest to whakatane

a mesoscale study of the elemental composition of aerosols emitted from mt etna volcano an aircraft survey was carried out for the study of the gaseous and particulate emissions over mt etna volcano in september 1983 samples were collected in the range from 10 to 300 km a satisfying conservation of the elemental composition of the aerosol has been observed some activity fluctuation 150 km from the emitter was attributed to an ash fall episode sampling assumed that some crustal elements in the volcanic aerosol can be used to measure the plume dilution factor new estimations of volcanic particulate fluxes are given

paleodiet in northern chile through the holocene extremely heavy δ15n values in dental calculus suggest a guano derived signature abstract dental calculus extracted from the teeth of 28 prehistoric human skeletons from coastal and valley archaeological sites in northern chile that date from the archaic period 2300 bc to the late intermediate period ad 1476 was analyzed for stable isotope 15 n 13 c compositions 15 n compositions were extremely heavy 17 8 to 33 1 but comparable to some studies using conventional human biomaterials hair nail muscle at other prehistoric sites in northern chile there was a negative correlation between 15 n and 13 c for coastal sites but a positive correlation for valley sites results for the valley sites point to a diet that was influenced by marine resources throughout all time periods the unusually heavy 15 n values for the coastal sites require a dietary component with a 15 n composition significantly heavier than that of marine resources the hyper aridity at the study area mean annual rainfall of 0 5 0 6 mm year is a likely contributing factor to the production of heavy 15 n values but is unlikely to account for the heaviest 15 n values 30 one possible explanation for the heaviest 15 n values is that dietary components were impacted by isotopically heavy guano which is abundant in the region guano may have been used as a fertilizer during crop cultivation at the onset of the formative period continuing through the historic period after spanish contact the indirect impact of guano from abundant bird habitats in the region may have influenced wild foodstuffs harvested throughout the pre agricultural period results provide support for the utility of dental calculus as a proxy for obtaining stable carbon and nitrogen isotope signatures for use in paleodietary studies

gas and particle emissions from soufriere hills volcano montserrat west indies characterization and health hazard assessment the soufriere hills volcano montserrat erupting since 18 july 1995 intensified its degassing in early 1996 with the continuing growth of the lava dome inside the summit crater during this period of increased activity between 11 and 18 march 1996 we measured gases and particles within the visible plume to determine whether at that time it posed a health risk to the population of plymouth the capital town which is 5 km southwest downwind and was then still occupied gravimetric measurements were made of total suspended particles tsp and particles having an aerodynamic diameter of less than 10 m pm10 measurements were made of sulphur dioxide so2 hydrochloric acid hcl hydrofluoric acid hf nitric acid hno3 acetic acid ch3cooh formic acid hcooh and particulate sulphate so4 2 chloride cl nitrate no3 fluoride f methanesulphonate ch3so3 acetate ch3coo formate hcoo ammonium nh4 sodium na and acidity h trace metals having human health implications chromium cr nickel ni cobalt co copper cu zinc zn arsenic as selenium se cadmium cd tin sn mercury hg and lead pb were also determined mean concentrations of hcl so2 and hf obtained in the town of plymouth were 14 0 5 9 and 0 8 ppbv respectively corresponding concentrations in the mixed plume on the crater edge were 533 168 and 22 ppbv there were no direct emissions of hno3 although nitrate was detected in coarse particles at the source higher concentrations of ch3cooh and hcooh were measured close to the crater mean tsp and pm10 were 64 and 15 g m 3 in plymouth and 455 and 47 g m 3 on the upper volcano slope aerosols were highly acidic at the source but rapidly neutralised during transport trace metals were enriched in the aerosol relative to crater surface material the concentrations of the acid gases sulphur dioxide in particular and particles were found to be too small to pose a health hazard at the time of these measurements when relatively modest volcanic activity was occurring

melt inclusion investigation of the volatile behaviour in historic alkali basaltic magmas of etna crystallization paths of basaltic 1763 eruption and hawaiitic 1865 and 1329 eruptions scoria from etna were deduced from mineralogy and melt inclusion chemistry the volatile behaviour was investigated through the study of melt inclusions trapped in the phenocrysts and those of the whole rocks and the matrix glasses the results from the 1763 eruption point to the early crystallization of olivine fo 81 7 from a water rich alkaline basalt with high cl 1750 2000 ppm and s 2100 2400 ppm concentrations the hawaiitic melt inclusions trapped in olivine fo 74 salite and plagioclase are characterized by a decrease in cl k2o and s k2o ratios in each investigated system there is good correlation between k2o and p2o5 in the whole rocks cl ranges from 980 to 1680 ppm from basaltic to hawaiitic lavas whereas s 110 136 ppm remains low cl and s behaviour in the 1763 magma suggests an early degassing stage of cl and s with co2 and a water rich gaseous phase for a pressure close to 100 mpa consistent with a permanent outgassing at the summit craters of etna during the eruption the sulphur remaining in the hawaiitic liquid is lost and the degassing of chlorine is limited such a degassing model can be extended to the 1865 and 1329a d eruptions

three years of so2 flux measurements of mt etna using an automated uv scanner array comparison with conventional traverses and uncertainties in flux retrieval 1 sviluppo di sistemi di monitoraggio dipartimento di protezione civile della regione sicilia 2 ingv istituto nazionale di geofisica e vulcanologia sezione di catania italy 3 novac network for observation of volcanic and atmospheric change eu funded sixth framework programme project 18354 4 uk nerc national centre for earth observation via the dynamic earth and geo hazards

sulfur and halogen gases at masaya caldera complex nicaragua total flux and variations with time santiago crater of masaya caldera complex near managua nicaragua entered a phase of intense magmatic degassing in late 1979 the flux of so2 increased rapidly from a previous average of 380 t d 1 to approximately 1200 t d 1 in february 1980 we report on results of a study of the gas flux and geochemistry conducted as part of a broader interdisciplinary study of the volcano and its impact on the adjacent environment masaya is an unusual volcano because of its low shield like form consistent tholeiitic basaltic composition frequent activity and especially because of the approximately 25 year cycle of major non eruptive degassing crises we have used a combination of techniques involving remote sensing using a correlation spectrometer cospec of the flux of so2 and direct filter sampling of the ratios of the sulfur and halogen gases and aerosols to quantify the flux of all of these species the three stage filters successively trap aerosols halogen acid gases and sulfur dioxide and are analyzed by ion chromatography we have used the ratios of various species with the cospec measurements of the flux of so2 to calculate that the average flux of so2 is 1275 t d 1 hcl is 830 t d 1 hf is about 16 t d 1 and hbr is at most 1 t d 1 h2s and so4 are only minor sulfur species the flux of so2 and hcl represents the largest reported noneruptive sustained volcanic release of these species in the world masaya contributed 7 of the total so2 estimated to have been released by volcanoes worldwide in 1981 the flux of so2 has declined by about 9 each year since 1979 and can be modeled as a first order kinetic rate law with a decay constant of approximately 0 04 yr 1 approximately 2 2 106 tons of so2 has been released between september 1979 and september 1985 the ratio s cl has declined more rapidly than the flux of so2 reflecting the greater solubility of hcl than so2 in the magma the so2 flux at santiago varies more widely within a single day than observed at other degassing volcanoes and may be controlled at least in part by effects of the solid earth tide an area larger than 500 km2 has been severely impacted downwind of the volcano downwind ground level concentrations of so2 of 0 25 ppm are frequently encountered acid rain unusually chloride rich has a ph as low as 2 63 s cl ratios in the gas plume increase downwind probably as a result of the high solubility and dry deposition velocity of hcl preliminary analyses of primary concentrations of sulfur and chlorine in the magma of the present lava lake are used to calculate that at least 1 2 km3 has been completely degassed with respect to sulfur to provide the observed flux this implies that 10 km3 have been degassed by previous crises in the past century and further suggests a magma supply rate of approximately 0 1 km3 yr comparable with kilauea or etna volcanoes during historic time only two lava flows have been extruded implying an unusually low ratio of extrusion intrusion of only 0 0007

trace elements in the particulate phase of the plume of masaya volcano nicaragua masaya volcano nicaragua has been passively degassing since 1993 this gas crisis provides a unique opportunity for investigating the degassing of magmatic volatiles here we studied the chemical composition of the volcanic particulate phase collected directly from the plume the objective was to gain new insights into the volatilities and emission rates of trace elements the results indicate enrichments in the aerosol phase of all analyzed trace elements including not only those known to be volatile such as cu and te but also elements considered as refractory such as rare earth elements rees and th rees were fractionated with a significant enrichment of light rare earth elements lrees over heavy rare earth elements hrees this pattern suggests degassing of lrees as chlorides in general the emission of most trace elements in volcanic plumes is governed by the primary degassing of chloride compounds however sem eds data and chemical analysis of aerosol filters allow us to state that trace elements can also be released as sulphate and chloro sulphate compounds the trace element emission rates at masaya are significant and place this volcano as a major gas emitter however for some elements like cu masaya s contribution to the global volcanic flux seems disproportionate probably pointing to the poor dataset available for other degassing volcanoes

evaluation of gases condensates and so2 emissions from augustine volcano alaska the degassing of a cl rich volcanic system after the march april 1986 explosive eruption a comprehensive gas study at augustine was undertaken in the summers of 1986 and 1987 airborne cospec measurements indicate that passive so2 emission rates declined exponentially during this period from 380 45 metric tons day t d on 7 24 86 to 27 6 t d on 8 24 87 these data are consistent with the hypothesis that the augustine magma reservoir has become more degassed as volcanic activity decreased after the spring 1986 eruption gas samples collected in 1987 from an 870 c fumarole on the andesitic lava dome show various degrees of disequilibrium due to oxidation of reduced gas species and condensation and loss of h2o in the intake tube of the sampling apparatus thermochemical restoration of the data permits removal of these effects to infer an equilibrium composition of the gases although not conclusive this restoration is consistent with the idea that the gases were in equilibrium at 870 c with an oxygen fugacity near the ni nio buffer these restored gas compositions show that relative to other convergent plate volcanoes the augustine gases are very hcl rich 5 3 6 0 mol hcl s rich 7 1 mol total s and h2o poor 83 9 84 8 mol h2o values of d and 18o suggest that the h2o in the dome gases is a mixture of primary magmatic water pmw and local seawater part of the cl in the augustine volcanic gases probably comes from this shallow seawater source additional cl may come from subducted oceanic crust because data by johnston 1978 show that cl rich glass inclusions in olivine crystals contain hornblende which is evidence for a deep source 25km for part of the cl gas samples collected in 1986 from 390 642 c fumaroles on a ramp surrounding the inner summit crater have been oxidized so severely that restoration to an equilibrium composition is not possible h and o isotope data suggest that these gases are variable mixtures of seawater fmw and meteoric steam these samples are much more h2o rich 92 97 h2o than the dome gases possibly due to a larger meteoric steam component the 1986 samples also have higher cl s s c and f cl ratios which imply that the magmatic component in these gases is from the more degassed 1976 magma thus the 1987 samples from the lava dome are better indicators than the 1986 samples of degassing within the augustine magma reservoir even though they were collected a year later and contain a significant seawater component future gas studies at augustine should emphasize fumaroles on active lava domes condensates collected from the same lava dome fumarole have enrichments ot 107 102 in cl br f b cd as s bi pb sb mo zn cu k li na si and ni lower temperature 200 650 c fumaroles around the volcano are generally less enriched in highly volatile elements however these lower termperature fumaroles have higher concentration of rock forming elements probably derived from the wall rock

silicate microspherules intercepted in the plume of etna volcano a possible volcanic origin has been suggested for the micrometre sized spherules that have been discovered in polar snows or ice cores1 5 and in the stratosphere6 7 however although such particles especially when black and magnetic have been identified among the tephra deposits of some volcanoes3 8 12 their volcanic emission has never been directly observed here we describe micro spherules intercepted in the plume of mount etna sicily during moderate recurring volcanic activity their study using analytical transmission and scanning electron microscopy atem and asem demonstrates the simultaneous presence in the plume of glassy silicate microspherules of various chemical compositions 47 98 sio2

fractionation of families of major minor and trace metals across the melt vapor interface in volcanic exhalations chemical families of metals fractionate systematically as they pass from a silicate melt across the interface with the vapor phase and on into a cooled volcanic plume we measured three groups of metals in a small suite of samples collected on filters from the plumes of kilauea hawaii usa etna sicily and merapi java volcanoes these were the major minor and trace metals of the alkali and alkaline earth families k rb cs ca sr ba a group of ordinarily rare metals cd cu in pb tl that are related by their chalcophile affinities and the radon daughter nuclides 210po 210bi and 210pb the measurements show the range and some details of systematic melt vapor fractionation within and between these groups of metals in the plumes of all three volcanoes the alkali metals are much more abundant than the alkaline earth metals in the kilauea plume the alkali metals are at least six times more abundant than the alkaline earth metals relative to abundances in the melt at etna the factor is at least 300 fractionations within each family are commonly also distinctive in the kilauea plume in addition to the whole alkaline earth family being depleted the heaviest metals of the family sr ba are progressively more depleted than the light metal ca in plumes of fumaroles at merapi k cs ratios were approximately three orders of magnitude smaller than found in other earth materials this may represent the largest observed enrichment of the light ion lithophile lil metals changes in metal ratios were seen through the time of eruption in the plumes of kilauea and etna this may reflect degree of degassing of volatiles with which metals complex from the magma bodies at kilauea the changes in fractionation were seen over about three years fractionation within the alkaline earth family increased and that between the two families decreased over that time all of the ordinarily rare chalcophile metals measured are extremely abundant in volcanic plumes and cd and tl are enriched relative to the others indium is much more abundant in the plume of the hotspot volcano kilauea than in the etna plume probably non hotspot in character it may be a useful indicator of the tapping of deep mantle zones or could aid in the interpretation of reports of pt group metals in exhalations from hot spot volcanoes indium in old glacial ice strata could help assess magnitude and variability of exhalations from hotspot volcanoes in past time strong melt vapor fractionation of the alkali and alkaline earth metals may only be observed in plumes during quiescent degassing of volcanoes when large amounts of ash or spatter undifferentiated lava enter the plume its alkali and alkaline earth metal composition may approach that of the melt ratios among the chalcophile metals may not be much changed by addition of ash because their concentrations in melt are so small and masses of them in any plume may remain dominated by transfer across the melt vapor interface radon daughter nuclides give information about state of volcanic activity at time of sampling the precisely known origins ultratrace detectability decay systematics and wide variations in volatility of these species provide information about residence times degassing and travel histories and identities of melt bodies in volcanic systems

high resolution size distributions and emission fluxes of trace elements from masaya volcano nicaragua active volcanoes are significant natural sources of trace elements to the atmosphere yet the processes of emission and the impacts of deposition into terrestrial and aquatic environments remain poorly understood the varying contributions of volatile degassing and magma ejection i e spattering spraying extrusion and fragmentation to the emission of trace elements from masaya volcano nicaragua are investigated through measurement of high resolution trace element size distributions using cascade impactors in 2009 and 2010 the volatile elements e g as cd tl cu pb zn are strongly correlated across the size distribution and exist in the plume primarily as fine sulfate 0 6 m diameter with lesser amounts transported as coarse sulfates 3 5 m diameter and coarse chlorides 11 m diameter these results suggest that trace elements released from the magma as chlorides react rapidly with h2so4 in the plume to form sulfates in contrast the non volatile elements e g alkali earth and rare earth exist primarily as particles in the 1 10 m range and show no correlation with sulfate chloride or the volatile elements suggesting that they are emitted primarily by magma ejection trace element emission fluxes from masaya in 2010 were estimated using filter pack measurements with emissions of cu zn as tl rb and cd each in excess of 10 kg d 1 these emission fluxes are similar to those measured in 2000 2001 suggesting notable decadal stability in the emission of trace elements from masaya

acid gas and metal emission rates during long lived basalt degassing at stromboli volcano the discharge of acid gases and metals from stromboli is determined from airborne and ground based filter sampling of particulate matter in the volcanic plume combined with cospec measurements of so2 fluxes smaller particle sizes and high enrichment factors distinguish the most volatile elements by order s se br cl cd bi in as sb sn f au pb cr cu from those strictly fe mn ree sc sr th ti v or mainly al ba ca co k na u derived from volcanic ash time averaged volatile fluxes show that stromboli is a representative arc emittor producing 1 2 of the global volcanic budget of sulfur halogens and several trace metals while 15 25 of volcanic emissions of bi cd cs pb and sn in southern italy subaerial degassing of its s cl rich shoshonitic magma over the last 2 ky of similar activity may have released as much copper and gold as is encountered in magma derived high sulfidation ore deposits

the role of sulfur in the formation of magmatic hydrothermal copper gold deposits abstract essential resources of many rare metals including copper zinc molybdenum silver and gold occur in natural sulfide mineral deposits understanding the origin of these metal resources has been limited by a lack of data about the geochemistry of sulfur the most important and abundant element of ore deposits we report the first directly measured sulfur concentrations in high temperature fluids together with their ore metal contents using a new method for sulfur quantification in fluid inclusions by laser ablation inductively coupled plasma mass spectrometry la icp ms co genetic brine and vapor inclusions from magmatic hydrothermal ore deposits and granitic intrusions show an excess of sulfur over ore metals as required for efficient ore mineral precipitation the results demonstrate that s cu and au are highly enriched in vapor like magmatic fluids implying that such low salinity fluids are the key agent for the formation of porphyry copper and epithermal gold deposits

atmospheric sources and sinks of volcanogenic elements in a basaltic volcano etna italy abstract this study reports on the first quantitative assessment of the geochemical cycling of volcanogenic elements from their atmospheric release to their deposition back to the ground etna s emissions and atmospheric depositions were characterised for more than 2 years providing data on major and trace element abundance in both volcanic aerosols and bulk depositions volcanic aerosols were collected from 2004 to 2007 at the summit vents by conventional filtration techniques precipitation was collected from 2006 to 2007 in five rain gauges at various altitudes around the summit craters analytical results for volcanic aerosols showed that the dominant anions were s cl and f and that the most abundant metals were k ca mg al fe and ti 1 5 50 g m 3 minor and trace element concentrations ranged from about 0 001 to 1 g m 3 from such analysis we derived an aerosol mass flux ranging from 3000 to 8000 t a 1 most analysed elements had higher concentrations close to the emission vent confirming the prevailing volcanic contribution to bulk deposition calculated deposition rates were integrated over the whole etna area to provide a first estimate of the total deposition fluxes for several major and trace elements these calculated deposition fluxes ranged from 20 to 80 t a 1 al fe si to 0 01 0 1 t a 1 bi cs sc th tl and u comparison between volcanic emissions and atmospheric deposition showed that the amount of trace elements scavenged from the plume in the surrounding of the volcano ranged from 0 1 to 1 for volatile elements such as as bi cd cs cu tl and from 1 to 5 for refractory elements such as al ba co fe ti th u and v consequently more than 90 of volcanogenic trace elements were dispersed further away and may cause a regional scale impact such a large difference between deposition and emission fluxes at mt etna pointed to relatively high stability and long residence time of aerosols in the plume

magnitude of lead flux to the atmosphere from volcanoes pb s tl s and bi s ratios were measured in eruptive and fumarolic volcanic gases and indexed to the global flux of volcanic s to characterize approximate global volcanic emissions of these three metals to the atmosphere which are about 1200 tons pb yr 600 tons tl yr and 4000 tons bi yr this volcanic pb input is similar to the magnitude of natural soil dust pb input which is about 1400 tons pb yr during the holocene interglacial both are negligible compared to annual industrial inputs of 300 000 tons pb yr which maintain the present tropospheric reservoir of pb however polar ice records indicate that thousands of years ago the atmospheric pb reservoir was only 1 of its present size which means that volcanic pb was the source of about half the pb in the atmosphere during preindustrial holocene times

fractionation of metals in volcanic emissions abstract the enrichment of some metals al mg na k cu zn cd in volcanic gases is measured by an emanation coefficient ex relating the amount of the element x in lavas and in aerosols ex is determined in the volcanic emissions of mount etna sicily with regard to that of210pb the accuracy of the results is limited by the geochemical behavior of common lead compared to that of210pb concerning the most volatile species it appears that practically all the volcanic aerosols are produced by evaporation followed by gas to particle conversion and the spattered fraction appears to be negligible

characterization of intrabasin faulting and deformation for earthquake hazards in southern utah valley utah from high resolution seismic imaging we conducted active and passive seismic imaging investigations along a 5 6 km long east west transect ending at the mapped trace of the wasatch fault in southern utah valley using two dimensional 2d p wave seismic reflection data we imaged basin deformation and faulting to a depth of 1 4 km and developed a detailed interval velocity model for prestack depth migration and 2d ground motion simulations passive source microtremor data acquired at two sites along the seismic reflection transect resolve s wave velocities of approximately 200 m s at the surface to about 900 m s at 160 m depth and confirm a substantial thickening of low velocity material westward into the valley from the p wave reflection profile we interpret shallow 100 600 m bedrock deformation extending from the surface trace of the wasatch fault to roughly 1 5 km west into the valley the bedrock deformation is caused by multiple interpreted fault splays displacing fault blocks downward to the west of the range front further west in the valley the p wave data reveal subhorizontal horizons from approximately 90 to 900 m depth that vary in thickness and whose dip increases with depth eastward toward the wasatch fault another inferred fault about 4 km west of the mapped wasatch fault displaces horizons within the valley to as shallow as 100 m depth the overall deformational pattern imaged in our data is consistent with the wasatch fault migrating eastward through time and with the abandonment of earlier synextensional faults as part of the evolution of an inferred 20 km wide half graben structure within utah valley finite difference 2d modeling suggests the imaged subsurface basin geometry can cause fourfold variation in peak ground velocity over distances of 300 m

geochemistry of metallic trace elements in fumarolic condensates from nicaraguan and costa rican volcanoes metallic trace element composition of volcanic gas from cerro negro momotombo san cristobal telica and masaya volcanoes in nicaragua and poas volcano in costa rica is indicated by analyses of fumarolic condensates for alkalis alkaline earths transition elements precious metals halogens and sulphate the temperatures of the fumaroles varied from 85 to 852 c element concentrations range from 104 to 10 3 ppm statistical tests indicate that the trace element constituents of the condensates are log normally distributed although there are variations in element concentrations in individual condensates the general order of decreasing elemental abundances in nicaraguan and costa rican fumarolic gas is cl so4 certain igneous rock forming elements si al fe ti f and alkalis li na k alkaline earths mg ca ba br and transition elements cr mn co ni cu zn other ore forming elements mo cd sn pb semi metals as sb sc hg and precious metals au ag li mn cr and pb were found to be near or below detection limits in many of the condensates analyzed so4 ti al k na zn sn cr and br all tend to decrease in abundance as mean fumarolic temperature between volcanoes decreases the remaining elements remain constant in abundance or behave erratically the metallic trace element composition of the nicaraguan and costa rican fumarolic condensates is very similar to condensates from subduction zone volcanoes around the pacific margin and the mediterranean metals in volcanic gas are postulated to have been transported as halogen sulphate and oxide compounds chloride and fluoride compounds are considered to be the primary transporters of metals in volcanic gas correlations between metal and halogen content vary considerably between volcanoes statistically significant correlations between metal content and both chlorine and bromine are found in the cerro negro and between metal content and bromine and fluorine in the momotombo condensates metal bearing compounds in volcanic gas are postulated from correlation matrices bromine though seldom reported in condensates is a minor but important constituent of volcanic gas with concentrations similar to those of fluorine metal bromide compounds have higher volatilities than fluoride compounds and volatilities similar to chloride compounds significant correlations between bromine content and metal concentration suggests that bromide compounds play a role in the transportation of metals in volcanic gas

s cl and f degassing as an indicator of volcanic dynamics the 2001 eruption of mount etna 1 the recent eruption of mount etna july 2001 offered the opportunity to analyze magma derived volatiles emitted during pre and syn eruptive phases and to verify whether their composition is affected by changes in volcanic dynamics this paper presents the results of analyses of f cl and s in the volcanic plume collected by filter packs and interprets variations in the composition based on contrasting solubility in magmas a rayleigh type degassing mechanism was used to fit the acquired data and to estimate henry s solubility constant ratios in etnean basalt this model provided insights into the dynamics of the volcano abundances of sulfur and halogens in eruptive plumes may help predict the temporal evolution of an ongoing effusive eruption

variability of alkali and heavy metal fluxes released by mt etna volcano sicily between 1991 and 1995 abstract we regularly collected volcanic gases and aerosols at mt etna volcano over a long period 1991 1995 and measured their chemical composition by icp ms based on these data we present new evidence on the high volatility of both alkali and some heavy metals in contrast both lanthanides and actinides are not produced as significant gaseous compounds at magmatic temperatures and can be used as tracers of spattered materials all metals of each chemical family maintained systematic trends during the study period at both summit craters and effusive vents located in the valle del bove during the 1991 1993 eruption during the eruption we observed high metal enrichments at effusive vents these enrichments seem to be characteristic of the secondary degassing of a magma previously degassed under the summit area lower metal enrichments are recorded in aerosols sampled in summit crater plumes according to the primary degassing type occurring at these vents while a primary degassing type still occurs at both bocca nuova and voragine during the post eruptive period sud est crater exhibits a transition from primary to secondary type according to the variations of the volcanic activity level we confirm that the alkali metals fractionate systematically within their family as they cross the melt vapour interface the heavier members being always more enriched than the lighter ones in aerosols we also show that this fractionation is not related to the volcanic activity and the degassing type but seems to be a significant feature of the alkali family itself estimation of new emanation coefficients for rubidium caesium tin and thallium 0 07 0 15 0 50 and 21 respectively yields annual outputs around 1000 t yr 60 t yr 240 t yr and 1600 t yr respectively mount etna is a very important source of metals injected into the atmosphere contributing to the global volcanic budget about 16 for heavy metals and 19 for alkali metals in eruptive periods and only 2 and 4 respectively in quiet periods

investigation of thallium fluxes from subaerial volcanism implications for the present and past mass balance of thallium in the oceans abstract a suite of 34 volcanic gas condensates and particulates from kilauea hawaii mt etna and vulcano italy mt merapi indonesia white island and mt nguaruhoe new zealand were analysed for both tl isotope compositions and tl pb ratios when considered together with published tl pb abundance data the measurements provide globally representative best estimates of tl pb 0 46 0 25 and e 205 tl 1 7 2 0 for the emissions of subaerial volcanism to the atmosphere and oceans e 205 tl is the deviation of the 205 tl 203 tl isotope ratio from nist srm 997 isotope standard in parts per 10 000 compared to igneous rocks of the crust and mantle volcanic gases were found to have i tl pb ratios that are typically about an order of magnitude higher and ii significantly more variable tl isotope compositions but a mean e 205 tl value that is indistinguishable from estimates for the earth s mantle and continental crust the first observation can be explained by the more volatile nature of tl compared to pb during the production of volcanic gases whilst the second reflects the contrasting and approximately balanced isotope fractionation effects that are generated by partial evaporation of tl during magma degassing and partial tl condensation as a result of the cooling and differentiation of volcanic gases mass balance calculations based on results from this and other recent tl isotope studies were carried out to investigate whether temporal changes in the volcanic tl fluxes could be responsible for the dramatic shift in the e 205 tl value of the oceans at 55 ma which has been inferred from tl isotope time series data for ferromanganese crusts the calculations demonstrate that even large changes in the marine tl input fluxes from volcanism and other sources are unable to significantly alter the tl isotope composition of the oceans based on modelling it is shown that the large inferred change in the e 205 tl value of seawater is best explained if the oceans of the early cenozoic featured significantly larger tl output fluxes to oxic pelagic sediments whilst the sink fluxes to altered ocean crust remained approximately constant

a total volatile inventory for masaya volcano nicaragua nerc project magma dynamics at persistently degassing basaltic volcanoes a novel approach to linking volcanic gases and magmatic volatiles within a physical model ne f004222 1 and ne f005342 1

halogens and trace metal emissions from the ongoing 2008 summit eruption of kīlauea volcano hawai i volcanic plume samples taken in 2008 and 2009 from the halema uma u eruption at k lauea provide new insights into k lauea s degassing behaviour the cl f and s gas systematics are consistent with syn eruptive east rift zone measurements suggesting that the new halema uma u activity is fed by a convecting magma reservoir shallower than the main summit storage area comparison with degassing models suggests that plume halogen and s composition is controlled by very shallow 77 as gaseous elemental mercury at the point of emission sulphate is an important aerosol component modal particle diameter 0 44 m aerosol halide ion concentrations are low compared to other systems consistent with the lower proportion of gaseous hydrogen halides plume concentrations of many metallic elements rb cs be b cr ni cu mo cd w re ge as in sn sb te tl pb mg sr sc ti v mn fe co y zr hf ta al p ga th u la ce pr nd sm eu gd tb dy er tm are elevated above background air there is considerable variability in metal to so2 ratios but our ratios generally at the lower end of the range previously measured at k lauea support assertions that k lauea s emissions are metal poor compared to other volcanic settings our aerosol re and cd measurements are complementary to degassing trends observed in hawaiian rock suites although measured aerosol metal s ratios are about an order of magnitude lower than those calculated from degassing trends determined from glass chemistry plume enrichment factors with respect to hawaiian lavas are in broad agreement with those from previous studies allowing similar element classification schemes to be followed i e lithophile elements having lower volatility and chalcophile elements having higher volatility the proportion of metal associated with the largest particle size mode collected 2 5 m and that bound to silicate is significantly higher for lithophiles than chalcophiles many metals show higher solubility in ph 7 buffer solution than deionised water suggesting that acidity is not the sole driver in terms of solubility nonetheless many metals are largely water soluble when compared with the other sequential leachates suggesting that they are delivered to the environment in a bioavailable form preliminary analyses of environmental samples show that concentrations of metals are elevated in rainwater affected by the volcanic plume and even more so in fog however metal levels in grass samples showed no clear enrichment downwind of the active vents

particle geochemistry of volcanic plumes of etna and mount st helens particles in volcanic plumes include vapor condensates and reaction products of ash with vapors or condensed liquids in addition to abundant silicate particles in the 1980 mount st helens plume we detected abundant na k cl crystals as well as ca sulfates the latter commonly as overgrowths on ash or anthropogenic particles many of the chloride particles contained zinc and cadmium high temperature fumarolic incrustations showed strong enrichments of arsenic zinc alkalis and iron at etna we did not detect chloride crystals but found abundant al fe and ca sulfates sulfuric acid droplets were ubiquitous in both plumes bulk analyses of fumarole incrustations at etna showed an enrichment in the rare earth elements ree the chemical and textural data of the plume particles indicate that chloride particles form relatively early and react later with sulfuric acid droplets to form sulfates at etna aluminum as well as some ree are probably transported as volatile fluorine compounds the differences in plume chemistry between etna and mount st helens are most likely related to differences in f cl ratios of the vapors based on the abundance of particulate chlorine in plumes we suggest that only a small fraction of the total chlorine released during an eruption might reach the stratosphere in the vapor phase

airborne aerosol measurements in the quiescent plume of mount st helens september 1980 atmospheric particulate matter and condensed volatile species were collected in the quiescent plume of mount st helens volcano in sept 1980 using air filter systems mounted aboard a nasa turbo prop p 3 aircraft concentrations of 27 elements were determined by instrumental neutron activation analysis and ion chromotagraphy the volatile elements cl br f zn w in s cd se sb hg as and au were enriched relative to bulk ash emitted during the earlier eruptions by factors of 50 to 20 000 particulate s concentrations were approx 3 mu g m sup 3 and accounted for 6 of the total plume sulfur gas phase hg concentrations were 2 5 to 16 ng m sup 3 fluxes of elements were estimated by normalizing elemental concentrations to the concurrently measured total sulfur flux emission rates vary from 3500 kg day for particulate cl to 3 kg day for au with substantial quantities of the enriched elements zn as hg sb se and cd also being released estimated global fluxes of these elements from volcanoes to the atmosphere are in reasonable agreement with other literature estimates

sweet chestnut castanea sativa leaves as a bio indicator of volcanic gas aerosol and ash deposition onto the flanks of mt etna in 2005 2007 sweet chestnut leaves castanea sativa collected from the flanks of mt etna volcano in 2005 2007 were analysed by inductively coupled plasma mass spectrometry to investigate the spatial and temporal variability of element concentrations the aim of this work was to determine whether these leaves are a bio indicator for volcanic gas aerosol and ash deposition and to gain new insights into the environmental effects of quiescent and eruptive volcanic plumes results show a positive correlation between sample variability in the concentration of elements in castanea sativa and enrichment factors of elements in the plume the spatial and temporal variability of chalcophilic elements as cd cu mo tl zn is consistent with prevailing winds transporting eruptive plumes to the south east of the summit resulting in enhanced plume deposition onto the flanks of the volcano similar spatial and temporal variability was found for the halide forming elements cs k rb and intermediate elements al co mn the spatial variability of chalcophilic intermediate and halide forming elements during quiescent periods was diminished relative to eruptive periods and could not be explained by plume deposition in contrast the concentrations of lithophilic elements ba ca mg sr did not show any clear spatial variability even during eruptive periods comparisons between enrichment factors for elements in castanea sativa and literature values for enrichment factors of the volcanic plume groundwater and lichen were made whilst castanea sativa offers insights into the spatial and temporal variability of deposition the species may not be a bio indicator for plume composition due to biological fractionation

small particles in plumes of mount st helens particles in the size range of 0 1 25 micrometers were sampled by aircraft carrying a quartz crystal microcascade in the mount st helens plume on three dates in august and september 1980 two of the sampling dates represented typical emissions of the volcano between plinian eruptions one sampling flight was made 1 4 hours before the small plinian eruption of august 7 1980 when the plume had become discontinuous and visibly darker size distributions were determined and individual particles were studied by using scanning electron microscopy the plume sampled on august 7 before the eruption contained mainly approximately 2 micrometer diameter silicic glass particles fragments of the mount st helens magma the typical plumes sampled on september 22 and august 6 had much smaller concentrations of particles trimodal size distributions with peaks at 10 0 4 and 0 1 micrometers the particles were largely nonsilicate and apparently represented cu zn oxide 10 micrometer peak al sulfate chloride and oxide and sulfuric acid smallest size peak the characterization of small particles in the plume may give information about approaching activity and possibly about changing conditions in the subsurface magma body

metal emissions from kilauea and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes abstract measurements of a large suite of metals pb cd cu zn and several others and sulfur at kilauea volcano over an extended period of time has yielded a detailed record of the atmospheric injection of ordinarily rare metals from this quiescently degassing volcano representative of an important type we have combined the kilauea data with data of recent studies by others emissions from volcanoes in the indonesian arc the large laki eruption of two centuries ago etna estimates of total volcanic emissions of sulfur to form the basis for a new working estimate of the rate of worldwide injection of metals to the atmosphere by volcanoes the new estimate is that volcanoes inject a substantially smaller mass of ordinarily rare metals into the atmosphere than was stated in a widely cited previous estimate j o nriagu a global assessment of natural sources of atmospheric trace metals nature 338 1989 47 49 our estimate which is an upper limit is an annual injection mass of about 10 000 tons of the metals considered versus the earlier estimate of about 23 000 tons also the proportions of the metals are substantially different in our new estimate