broadband recording of strombolian explosions and associated very long period seismic signals on mount erebus volcano ross island antarctica in december 1996 and january 1997 broadband seismometers were deployed on the summit plateau of mount erebus at radial distances of 0 7 1 4 and 1 9 km from the central crater and lava lake strombolian explosions at erebus previously have been observed to produce seismic and acoustic energy between 1 and 6 hz new observations document significant energy with spectral peaks as grave as 20 s nearly identical very long period vlp signals begin 1 5 s prior to explosions have dilatational onsets and persist for up to 150 s similar vlp waveforms were recorded at all three stations indicating that the seismograms are essentially source dominated particle motions suggest an initial depth for the vlp source of up to several hundred meters migrating deeper in the course of 15 s such explosion associated vlp signals may indicate a nondestructive lossy resonance or nonlinear fluid flow excitation within the shallow magmatic system

copper isotope fractionation in sedimentary copper mineralization timna valley israel abstract copper isotopes 65 cu 63 cu are potentially powerful new geochemical proxies for oxidation reduction processes and metallic cycling this research presents a cu isotope study of mineralization in historically mined stratiform sediment hosted copper ssc ore deposits of the precambrian and cambrian rocks of the timna valley southern israel these deposits provide a natural laboratory for studying isotopic fractionations between cu sulphides and cu ii minerals copper carbonates hydroxides and silicates formed during sequential cycles of low temperature alteration of igneous copper porphyries marine sedimentary diagenesis and epigenetic mobilization in sandstones isotopic measurements were made using mc icp ms after ion chromatographic separation of the copper from matrix elements in accord with abiogenic experimental studies showing that there should be a negative isotopic fractionation between reduced and oxidized copper minerals 65 cu values of cu sulphides are significantly lower 3 4 to 1 2 than coexisting cu ii carbonates and hydroxides 1 2 to 0 5 cu ii silicates which should only show a very small isotopic fractionation relative to parent cu ii solutions give average 65 cu values of 0 09 0 24 consistent with the fact that the primary source of sedimentary copper was the precambrian igneous rocks isotopic zoning profiles in cu sulphides of the cambrian dolomites suggest they were formed through the interaction of small disconnected cu solution reservoirs with h 2 s formed by bacterial reduction of sulphate containing pore waters mass balance modeling based on the measured cu isotope compositions and experimental fractionation factors shows that the main copper reservoir is the cambrian sandstone shale sequence and that the cu sulphide reservoirs are relatively small thus most of the copper transport occurred in relatively oxidized conditions the calculated reservoir sizes are in agreement with field observations and confirm that copper isotopes are able to trace both the oxidation reduction cycles and mass transfer during sedimentary copper mineralization

very long period oscillations of mount erebus volcano as the signal decays vlp scalar moments up to 5 10 11 n m exceed sp moments by an order of magnitude or more suggesting distinct though genetically related sp and vlp source mechanisms we conclude that vlp signals arise from excitation of a quasi linear resonator that is intimately associated with the conduit system and is excited by gravity and inertial forces associated with gas slug ascent eruption and magma recharge vlp signal stability across hundreds of eruptions spanning 5 years the persistence of the lava lake and the rapid posteruptive lava lake recovery indicate a stable near summit magma reservoir and vlp source process index terms 4544 oceanography physical internal and inertial waves 7280 seismology volcano seismology 8419 8414 volcanology eruption mechanisms 8419 volcanology eruption monitoring 7280 keywords strombolian very long period volcano seismology

detrital zircon u pb geochronology of southern guerrero and western mixteca arc successions southern mexico new insights for the tectonic evolution of southwestern north america during the late mesozoic late jurassic cretaceous arc related volcaniclastic rocks from the southern guerrero and western mixteca terranes of mexico were analyzed by u pb detrital zircon geochronology laser ablation multicollector inductively coupled plasma mass spectroscopy to place constraints on the depositional history and provenance of the rocks pre middle jurassic basement rocks and sandstone from the upper cretaceous mexcala formation were also analyzed to defi ne the origin and provenance of the prevolcanic substratum and the time of accretion of guerrero composite terrane sequences data from the taxco taxco viejo teloloapan and arcelia assemblages indicate that the youngest 129 141 ma zircon fraction in each sequence was derived from local volcanic sources whereas older populations ca 247 317 365 459 530 617 712 878 947 964 1112 1188 1350 1420 1842 1929 2126 2439 and 2709 3438 ma show sediment infl ux from varied sources most likely through grain recycling the major zircon clusters in these sequences match the populations recorded in the nearby acatlan complex in contrast the huetamo sample is dominated by lower cretaceous ca 126 ma zircons of local volcanic provenance and the zihuatanejo sample contains zircon clusters ca 259 ca 579 and ca 947 1162 ma comparable to major populations recorded in the underlying arteaga complex a sample from the middle triassic middle jurassic arteaga complex at tzitzio contains zircon clusters ca 202 247 ca 424 ca 600 ca 971 and ca 2877 ma consistent with an ultimate derivation from both north american and south american sources the sample from the las ollas suite contains comparable zircon populations ca 376 475 ca 575 ca 988 1141 and ca 2642 2724 ma and it is interpreted to be part of the prevolcanic basement in contrast the youngest zircon cluster ca 105 ma in the mexcala formation coincides with the major volcanic events in the taxco taxco viejo teloloapan and arcelia assemblages whereas the older clusters ca 600 ca 953 ca 1215 ca 1913 and ca 2656 2859 ma broadly match the major populations recorded in rocks from the acatlan complex these new data combined with available geochemical and isotopic data indicate that the taxco taxco viejo arc assemblage developed on continental crust the acatlan complex is the most plausible candidate the teloloapan and arcelia arc assemblages were developed on oceanic crust as offshore arcs facing the acatlan complex the zihuatanejo terrane assemblages were developed on the arteaga complex and evidence no infl uence from the acatlan complex this suggests that these assemblages were formed farther away or in a restricted basin the guerrero composite and mixteca arc successions are coeval with the alisitos arc of northern mexico and in part with the nevada and klamath ranges of the southwestern united states and with the arc series from the greater and lesser antilles and northern south america data indicate that during late mesozoic time southwestern north america was a site of intensive volcanism in a complex arc trench system similar to that of the east pacifi c our data are consistent with a diachronic accretion of the guerrero composite terrane sequences beginning during late cenomanian time with the amalgamation of the teloloapan and probably the arcelia assemblages and fi nishing at the end of cretaceous time with the accretion of the zihuatanejo terrane assemblages

geochemical behavior of cu and sulfur isotopes in the tropical mining region of taxco guerrero southern mexico abstract this study was aimed to identify the main processes involved in the release of metals using sulfur isotopes and those acting on the fractionation of copper isotopes we determined sulfur and copper isotopic ratios in rocks tailings precipitates and soils samples from the historical mining district of taxco southern mexico ratios of sulfur isotopes are reported in notation of per mil and standardization was based on international standards ogs 1 and nbs123 only copper ratio isotopes were studied in pyrite py sphalerite sph and galena results are reported as 65cu 65cu 63cusample 65cu 63cunist976standar 1 1000 error for all the analyzed samples was 0 01 and any mass bias was corrected trough bracketing method the sulfur isotopic value of a sample from the mexcala shale formation was 7 7 the 34s values in tailing ponds ranged from 2 6 to 1 2 in precipitates from 7 2 to 3 2 and in soils from 0 8 to 4 5 isotopic 34s values in rocks evidenced a magmatic influence of sulfides present in the mexcala formation oxidation of sulfides contained in tailings and precipitates was observed related with their low 34s values close to zero oxidation followed the order sphalerite pyrite pyrite rich in copper chalcopyrite galena in soils oxidation is not the main process as supported by their positive 34s values and low sulfate content results of 65cu values in rocks were 0 09 to 0 54 in sulfides values were 65cu 0 18 py and 65cu 0 20 sph concentration of copper in galena was not enough to get a reliable isotopic value in tailings 65cu ranged from 1 19 to 0 91 and in precipitates from 0 36 to 0 92 in soils values were between 0 26 and 1 72 results in rocks indicate an igneous influence on copper provenance the 65cu values in py and sph were within the range of terrestrial primary sulfides from 1 to 1 confirming its igneous provenance processes related with fractionation of copper isotopes were oxidation of tailings and reprecipitation of 65cu in tailings with a high content of fe oxyhydroxides enrichment in 65cu in precipitates and soils is favored by organic matter presence that retains 63cu erosion of rocks and tailings is the main source of copper being rocks the initial and tailings the end members the isotopic studies on environmental research provide a useful tool on 1 the behavior of copper and sulfur isotopes in environments where both natural and anthropogenic activities are present 2 understanding surficial processes of dispersion of metals and identifying their source in mining areas surrounded by villages and agricultural soils

hidden dykes detected on ultra long period seismic signals at piton de la fournaise volcano broadband seismic data enable us to test whether ultra long period ulp signals can be used to investigate magma chamber pressure state and to monitor volcanic eruptions by systematically investigating seismic signals at geoscope station rer we find ulp signals associated with volcanic events during the last 2 decades we tentatively propose to interpret these signals as events highlighting the activity of the upper magma feeding system of the piton de la fournaise volcano and as being related to the deep magma chamber some of these unusual signals were previously detected and usually interpreted in term of tilt battaglia j aki k montagner j j p tilt signals derived from a geoscope vbb station on the piton de la fournaise volcano geophys res lett 27 5 2000 605 608 they are detected using sts1 seismometers sensitive in the bandwidth 10 3 to 10 2 hz this alternative model enables to quantify each event in terms of a pressure drop in the upper magma reservoir of the volcano two kinds of seismic waveforms can be associated with two types of fracturing events the first one is related to the fast rise of a magma batch coming from the deep magma chamber and the second is the result of a slow rise in pressure inside a shallow reservoir in both cases we are able to detect these events on very long period seismic data the interpretation of these signals supports the idea of a single magma source at the sea level thus we propose to classify all the eruptions occurring during the last two decades into two groups corresponding to the two primary pressure states of the magma chamber 2007 elsevier b v all rights reserved

seismic source mechanism of degassing bursts at kilauea volcano hawaii results from waveform inversion in the 10 50 s band the current march 2008 to february 2009 summit eruptive activity at kilauea volcano is characterized by explosive degassing bursts accompanied by very long period vlp seismic signals we model the source mechanisms of vlp signals in the 10 50 s band using data recorded for 15 bursts with a 10 station broadband network deployed in the summit caldera to determine the source centroid location and source mechanism we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account the vlp signals associated with the bursts originate in a source region 1 km below the eastern perimeter of halemaumau pit crater the observed waveforms are well explained by the combination of a volumetric component and a vertical single force component for the volumetric component several source geometries are obtained which equally explain the observed waveforms these geometries include 1 a pipe dipping 64 to the northeast 2 two intersecting cracks including an east striking crack dike dipping 80 to the north intersecting a north striking crack another dike dipping 65 to the east 3 a pipe dipping 58 to the northeast intersecting a crack dipping 48 to the west southwest and 4 a pipe dipping 57 to the northeast intersecting a pipe dipping 58 to the west southwest using the dual crack model as reference the largest volume change obtained among the 15 bursts is 24 400 m3 and the maximum amplitude peak to peak of the force is 20 gn each burst is marked by a similar sequence of deflation and inflation trailed by decaying oscillations of the volumetric source the vertical force is initially upward synchronous with source deflation then downward synchronous with source reinflation followed by oscillations with polarity opposite to the volumetric oscillations this combination of force and volume change is attributed to pressure and momentum changes induced during a fluid dynamic source mechanism involving the ascent expansion and burst of a large slug of gas within the upper 150 m of the magma conduit as the slug expands upon approach to the surface and more liquid becomes wall supported by viscous shear forces the pressure below the slug decreases inducing conduit deflation and an upward force on the earth the final rapid slug expansion and burst stimulate vlp and lp oscillations of the conduit system which slowly decay due to viscous dissipation and elastic radiation consideration of the fluid dynamic arguments leads us to prefer the dual crack vlp source model as it is the only candidate model capable of producing plausible values of length scales and pressure changes the magnitudes of the vertical forces observed in the 15 bursts appear consistent with slug masses of 104 to 106 kg

application of near real time radial semblance to locate the shallow magmatic conduit at kilauea volcano hawaii 1 radial semblance is applied to broadband seismic network data to provide source locations of very long period vlp seismic energy in near real time with an efficient algorithm and adequate network coverage accurate source locations of vlp energy are derived to quickly locate the shallow magmatic conduit system at kilauea volcano hawaii during a restart in magma flow following a brief pause in the current eruption the shallow magmatic conduit is pressurized resulting in elastic radiation from various parts of the conduit system a steeply dipping distribution of vlp hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the halemaumau pit crater the distinct hypocenters suggest the shallow plumbing system beneath halemaumau consists of a complex plexus of sills and dikes an unconstrained location for a section of the conduit is also observed beneath the region between kilauea caldera and kilauea iki crater

highlights from a seismic broadband array on stromboli volcano an array of nine three component broadband seismometers was deployed in two different configurations on stromboli volcano the analysis of the seismic wavefield related to volcanic explosions revealed some observations which offer a completely new insight into the internal dynamics of a volcano these new observations are restricted to the low frequency range below 1 hz and underline therefore the superiority of broadband recordings over conventional short period observations surprisingly simple wavelets indicate an initially contracting source mechanism gas jets that could not be seen in a short period seismic record at all generate a clear dilatational wavelet in a broadband recording suggesting the same contracting source mechanism the analysis of particle motion and seismic array techniques permits a location of the seismic source we find low frequency signals of 3s and 6s period that are not related to eruptions and do not share a common source with the eruption related events a video recording of visible volcanic activity at the crater region allows one to correlate precisely eruptive features with seismic signals

monitoring very long period seismicity at kilauea volcano hawaii 1 on 19 march 2008 eruptive activity returned to the summit of kilauea volcano hawaii with the formation of a new vent within the halemaumau pit crater the new vent has been gradually increasing in size and exhibiting sustained degassing and the episodic bursting of gas slugs at the surface of a lava pond 200 m below the floor of halemaumau the spectral characteristics source location obtained by radial semblance and hidden markov model pattern recognition of the degassing burst signals are consistent with an increase in gas content in the magma transport system beginning in october 2007 this increase plateaus between march september 2008 and exhibits a fluctuating pattern until 31 january 2010 suggesting that the release of gas is slowly diminishing over time

performance of the radial semblance method for the location of very long period volcanic signals we investigate the performance of a source location method that com bines multichannel semblance and particle motions and is being increasingly used to obtain estimates of the source locations of very long period vlp seismic signals recorded on volcanoes the method makes use of the radial particle motions and large wavelengths that characterize the vlp events to assess the capabilities of this radial semblance method and to better understand its limitations we quantify the effects of window length noise contents of the signal inaccurate velocity models receiver coverage and orientation errors in the horizontal components of the receiv ers our results show that the semblance method performs best when 1 the noise level is low enough to allow a good characterization of the waveforms 2 the sources are located at distances between one half of the average receiver spacing and about two times the network aperture and 3 the orientations of the horizontal components of the seismometers are known with relative accuracy when these requirements are met the radial semblance method constitutes an adequate tool to obtain preliminary locations of vlp volcanic signals recorded by broadband networks moreover we provide a formula to determine the radial semblance level that should be used to define error regions associated to the estimated source locations

variations of pb in a mine impacted tropical river taxco mexico use of geochemical isotopic and statistical tools abstract the potential environmental threat from pb in mexican rivers impacted by historic mining activities was studied using geochemical isotopic and statistical methods lead geochemical fractionation and factor analysis of fractionated and total pb indicate that anthropogenic sources have contributed significantly to pb concentrations while natural sources have contributed only small amounts the analyses also indicate that two main processes are controlling the total pb variation throughout the year in both rivers erosion with discharge processes and proportional dilution related to differences in grain size distribution processes bio available pb in riverbed sediments was greater than 50 in 80 of the sampling stations indicating a high potential environmental risk according to the risk assessment criteria rac nevertheless based on the environmental chemistry of pb and on multivariate statistical analysis these criteria did not apply in this particular case significant differences p 1 in the case of the cacalotenango river 210pb did show preferential accumulation in sediments second a 210pb 214pb ratio of

geochemical evidence for mixing between fluids exsolved at different depths in the magmatic system of mt etna italy abstract a 4 year geochemical survey of some fumaroles at the voragine summit crater of mt etna was performed in combination with synchronous monitoring of peripheral gas emissions at the base of the volcano this was the first geochemical study at mt etna to have included the abundances of ar he and c isotopes once the effects of postmagmatic shallow processes were identified and quantitatively removed the he ar co 2 systematics of the voragine crater fumaroles and peripheral gas emissions described the same degassing path combining the carbon isotope composition with information about noble gases provided evidence that the crater fumaroles are fed from a two endmember mixture composed of a deep member coming from pressures between 200 and 400 mpa depending on time and a shallower one exsolved at 130 mpa similar mixing processes probably also occur in gases from peripheral vents the simultaneous assessment of 13 c co2 and he ar values of crater fumaroles over time has identified simple changes in the mixing proportion between the two endmembers and moreover periods during which the exsolution pressure of the deep fluid increased these periods seem to be linked to pre eruptive phases of the volcano the identified open system degassing processes are indicative of efficient bubble melt decoupling at depth whereas the mixing process requires a convective transfer of the deeply exsolved fluids toward shallower levels of magma where further vapor is exsolved in agreement with the most recent geophysical and petrological data from mt etna these observations allow inferences about a deep portion of the plumbing system 5 to 12 km b s l comprising sill like reservoirs connected by small vertical structures and a main reservoir at 2 3 km b s l that is probably fluxed by magmatic volatiles

water rock tailings interactions and sources of sulfur and metals in the subtropical mining region of taxco guerrero southern mexico a multi isotopic approach abstract multi isotope h o s sr pb systems coupled with conventional major and trace element hydrogeochemical analysis were applied to determine the origin of water to model water rock tailings interactions and for source apportionment of sulfur and associated toxic metals in the mining region of taxco guerrero in southern mexico oxygen and h isotopes indicate that meteoric water in the zone is rainwater undergoing varying degrees of isotopic fractionation by atmospheric evaporation whereas sr isotopes trace the interaction of pristine water from volcanics of the regional recharge zone and subsequently flowing through sandstone and shale to spring points leachates form from two distinctive sources spring water and surface water having differential interactions with bedrocks prior to entering the tailings compared to pristine water leachates are enriched in sulfate metals e g fe mn pb and zn and metalloids e g as the sulfur isotopic composition of ore sulfides leachates secondary precipitates regional surface water and hypogenic sulfates is described in terms of a two component mixing model with shale of mexcala and limestone of morelos formations representing the light and heavy end members respectively whereas sr isotopic composition is bracketed combining three lithogenic mexcala morelos tilzapotla and taxco schist sources finally leachates have a mixture of lead from ore sulfides and taxco schist formation family i or from ore sulfides alone family ii the application of multiple environmental isotopic techniques is an outstanding tool for elucidating complex interactions of water with bedrocks and tailings and for determining the source of sulfur and toxic metal from mining and other metal polluted environments

zn and cu isotopic variability in the alexandrinka volcanic hosted massive sulphide vhms ore deposit urals russia abstract copper and zn isotope ratios of well characterized samples from three ore facies in the devonian alexandrinka volcanic hosted massive sulphide vhms deposit southern urals were measured using multi collector icp ms mc icp ms and show variations linked to depositional environment and mineralogy the samples analysed derived from a hydrothermal metasomatic vein stockwork b a hydrothermal vent chimney and c reworked clastic sulphides as the deposit has not been significantly deformed or metamorphosed after its formation it represents a pristine example of ancient seafloor mineralization variations in 65 cu where 65 cu 65 cu 63 cu sample 65 cu 63 cu standard 1 1000 and 66 zn where 66 zn 66 zn 64 zn sample 66 zn 64 zn standard 1 1000 of 0 63 and 0 66 respectively are significantly greater than analytical uncertainty for both isotope ratios 0 07 2 very limited isotopic fractionation is observed in primary cu minerals from the stockwork and chimney whereas the zn isotopic composition of the stockwork varies significantly with the mineralogy chalcopyrite bearing samples from the stockwork have lighter 66 zn by 0 4 relative to sphalerite dominated samples which may be due to equilibrium partitioning of isotopically light zn into chalcopyrite during its precipitation 66 zn also showed significant variation in the chimney with an enrichment in heavy isotopes toward the chimney rim of 0 26 which may be caused by changing temperature hence fractionation factor or raleigh distillation post depositional seafloor oxidative dissolution and re precipitation in the clastic sediments possibly coupled with leaching led to systematic negative shifts in cu and zn isotope compositions relative to the primary sulphides copper shows the most pronounced fractionation consistent with the reduction of cu ii to cu i during supergene mineralization however the restricted range in 65 cu is unlike modern sulphides at mid oceanic ridges where a large range of cu isotope of up to 3 has been observed rouxel o fouquet y ludden j n 2004 copper isotope systematics of the lucky strike rainbow and logatchev sea floor hydrothermal fields on the mid atlantic ridge econ geol 99 585 600 zhu x k o nions r k guo y belshaw n s rickard d 2000 determination of natural cu isotope variation by plasma source mass spectrometry implications for use as geochemical tracers chem geol 163 139 149

radar doppler velocimetry of volcanic eruptions theoretical considerations and quantitative documentation of changes in eruptive behaviour at stromboli volcano italy summary the use of radar doppler velocimetry for the observation of volcanic activity is new we used this method to continuously observe the activity of one vent of stromboli volcano italy from the end of 2000 april until early may during this period we recorded 702 eruptions 132 of which occurred before a strong rain storm passed over the island on april 29 in order to interpret the recorded doppler data we developed a program that simulates different strombolian eruption scenarios for which we then calculate the theoretical doppler spectra comparing our theoretical data with the observed data we are able to show that most of the eruptions are nearly vertical although we did observe only one component of the eruption vector with our doppler radar one of the most interesting features of the data set is a significant change in eruptive behaviour that correlates with the occurrence of the rain storm we find that on average the eruption duration increased by a factor of 2 eruptive velocities were much higher and indirect evidence indicates that the average particle diameter of the erupted material decreased this change may have several causes but the coincidence with the rain storm may be evidence of magma water interaction and feedback on the volcanic activity if the fluid source rain changing the eruptive style is at the surface and in near surface layers then the main control on final eruption dynamics at stromboli volcano must also be in rather shallow regions

geochemistry and stable isotope composition of fresh alkaline porphyry copper tailings implications on sources and mobility of elements during transport and early stages of deposition abstract prevention of acid mine drainage amd in sulfide containing tailings requires the identification of the geochemical processes and element pathways in the early stages of tailing deposition however analyses of recently deposited tailings in active tailings impoundments are scarce because mineralogical changes occur near the detection limits of many assays this study shows that a detailed geochemical study which includes stable isotopes of water 2h 18o dissolved sulfates 34s 18o and hydrochemical parameter ph eh doc major and trace elements from tailings samples taken at different depths in rainy and dry seasons allows the understanding of weathering oxidation dissolution sorption and desorption water and element pathways and mixing processes in active tailings impoundments fresh alkaline tailings ph 9 2 10 2 from the cu mo porphyry deposit in el teniente chile had low carbonate 0 8 1 1 wt caco3 equivalent and sulfide concentrations 0 8 1 3 wt mainly as pyrite in the alkaline tailings water mo and cu up to 3 9 mg l mo and 0 016 mg l cu were mobile as moo42 and cu oh 20 during the flotation tailings water reached equilibrium with gypsum up to 738 mg l ca and 1765 mg l so4 the 34s vs 18o covariations of dissolved sulfate 2 3 to 4 5 34s and 4 1 to 6 0 18o revealed the sulfate sources the dissolution of primary sulfates 12 0 to 13 2 34s 7 4 to 10 9 18o and oxidation of primary sulfides 6 7 to 1 7 34s sedimented tailings in the tailings impoundment can be divided into three layers with different water sources element pathways and geochemical processes the deeper sediments 1 m depth were infiltrated by catchment water which partly replaced the original tailings water especially during the winter season this may have resulted in the change from alkaline to near neutral ph and towards lower concentrations of most dissolved elements the neutral ph and high doc up to 99 4 mg l c of the catchment water mobilized cu up to 0 25 mg l due to formation of organic cu complexes and zn up to 130 mg l due to dissolution of zn oxides and desorption at 1 m depth tailings pore water obtained during the winter season was chemically and isotopically similar to fresh tailings water ph 9 8 10 6 26 7 35 5 mg l cl 2 3 6 0 mg l mo during the summer a vadose zone evolved locally and temporarily up to 1 2 m depth resulting in a higher concentration of dissolved solids in the pore water due to evaporation during periodical new deposition of fresh tailings the geochemistry of the surface layer was geochemically similar to fresh tailings in periods without deposition sulfide oxidation was suggested by decreasing ph 7 7 9 5 enrichment of moo42 and so42 and changes in the isotopic composition of dissolved sulfates further enrichment for na k cl so4 mg cu and mo up to 23 8 mg l mo resulted from capillary transport towards the surface followed by evaporation and the precipitation of highly soluble efflorescent salts e g mirabilite syngenite at the tailing surface during summer

very long period conduit oscillations induced by rockfalls at kilauea volcano hawaii 1 eruptive activity at the summit of kilauea volcano hawaii beginning in 2010 and continuing to the present time is characterized by transient outgassing bursts accompanied by very long period vlp seismic signals triggered by rockfalls from the vent walls impacting a lava lake in a pit within the halemaumau pit crater we use raw data recorded with an 11 station broadband network to model the source mechanism of signals accompanying two large rockfalls on 29 august 2012 and two smaller average rockfalls obtained by stacking over all events with similar waveforms to improve the signal to noise ratio to determine the source centroid location and source mechanism we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account we apply a new waveform inversion method that accounts for the contributions from both translation and tilt in horizontal seismograms through the use of green s functions representing the seismometer response to translation and tilt ground motions this method enables a robust description of the source mechanism over the period range 1 1000 s the vlp signals associated with the rockfalls originate in a source region 1 km below the eastern perimeter of the halemaumau pit crater the observed waveforms are well explained by a simple volumetric source with geometry composed of two intersecting cracks including an east striking crack dike dipping 80 to the north intersecting a north striking crack another dike dipping 65 to the east each rockfall is marked by a similar step like inflation trailed by decaying oscillations of the volumetric source attributed to the efficient coupling at the source centroid location of the pressure and momentum changes induced by the rock mass impacting the top of the lava column assuming a simple lumped parameter representation of the shallow magmatic system the observed pressure and volume variations can be modeled with the following attributes rockfall volume 200 4500 m3 length of magma column 120 210 m diameter of pipe connecting the halemaumau pit crater to the subjacent dike system 6 m average thickness of the two underlying dikes 3 6 m and effective magma viscosity 30 210 pa s most rockfalls occur during episodes of sustained deflation of the kilauea summit the mass loss rate in the shallow magmatic system is estimated to be 1400 15 000 kg s 1 based on measurements of the temporal variation of vlp period in the two large rockfalls that occurred on 29 august 2012

three dimensional velocity structure of the kilauea caldera hawaii high resolution velocity models 0 5 km resolution of the kilauea caldera region are obtained by the tomographic inversion of both p and s wave arrival times data are from the permanent hawaiian volcano observatory hvo seismic network a broadband seismic network and a temporary array of stations centered on the southern boundary of the caldera a low velocity p wave anomaly is imaged centered on the southeastern edge of the caldera with a velocity contrast of about 10 and a volume of 27 km the vp vs model mimics the spatial extent of the p wave anomaly but is partitioned into two discrete anomalous volumes centered on the southern boundary of the caldera and on the upper east rift of the volcano the corresponding poisson s ratio in these zones is high 0 25 0 32 which is consistent with a densely cracked hot volume which may contain partial melt the large scale features of the models are consistent with results obtained from an earlier larger scale 2 km resolution tomographic image of kilauea volcano based on hvo network data

late middle to late pleistocene paleoecology and paleoenvironments in the coastal plain of rio grande do sul state southern brazil from stable isotopes in fossils of toxodon and stegomastodon abstract stable isotopes 13 c 18 o in teeth of extinct mammals have been used as indicators of diets and climate conditions which in turn are used for paleoenvironmental reconstructions the first analysis of stable isotopes in pleistocene mammals from southern brazil is reported here the analyzed taxa were the notoungulate toxodon and the proboscidean stegomastodon from late middle to late pleistocene fossiliferous beds exposed along chui creek in the coastal plain of rio grande do sul state the 13 c isotopes indicate that toxodon was a mixed feeder that fed mostly on c4 plants while stegomastodon was a browser to mixed feeder with preference for c3 plants with less c4 plants in the diet compared to modern african elephants comparison with carbon isotopic values in fossils of these taxa from other late quaternary localities in south america shows an increased proportion of c3 plants in the diets of both toxodon and stegomastodon in higher latitudes the values of 18 o in both taxa seem to reflect the isotopic composition of the ingested water rather than the isotopic content in the plants of which they fed on and the observed variations are likely to mirror variations of the patterns of precipitation paleoclimatic inferences and possible causes for the pseudo extinction of these taxa in southern brazil are also discussed

characterizing complex eruptive activity at santiaguito guatemala using infrasound semblance in networked arrays abstract we implement an infrasound semblance technique to identify acoustic sources originating from volcanic vents and apply the technique to the generally low amplitude infrasound

real time monitoring and massive inversion of source parameters of very long period seismic signals an application to stromboli volcano italy 1 we present a comprehensive processing tool for the real time analysis of the source mechanism of very long period vlp seismic data based on waveform inversions performed in the frequency domain for a point source a search for the source providing the best fitting solution is conducted over a three dimensional grid of assumed source locations in which the green s functions associated with each point source are calculated by finite differences using the reciprocal relation between source and receiver tests performed on 62 nodes of a linux cluster indicate that the waveform inversion and search for the best fitting signal over 100 000 point sources require roughly 30 s of processing time for a 2 min long record the procedure is applied to post processing of a data archive and to continuous automatic inversion of real time data at stromboli providing insights into different modes of degassing at this volcano

u series dating and taphonomy of quaternary vertebrates from brazilian caves abstract the geochronology and taphonomy of internationally important fossil bearing cave deposits were studied both in the semi arid northern bahia area and the subtropical southeastern lagoa santa area of brazil taphonomic analysis suggests that the processes responsible for bone accumulation in the brazilian caves vary between sites and taphonomic bias can therefore be significant in causing differences in faunal composition in the toca da boa vista caves the presence of single articulated skeletons and the entrance related distribution indicate that random penetration of animals is the main mechanism of fossil accumulation a process that biases the assemblage to smaller species and takes place over extended time periods in nearby toca dos ossos cave transport by runoff in the cave river is predominant and biases the fauna remains to larger more robust bones and species deposition probably also occurred only at times of enhanced runoff giving a more contemporaneous assemblage similar processes were responsible for emplacement of the copious fossil remains in the more humid lagoa santa area where terrigenous fossil deposits are found intercalated by massive speleothem calcite layers in this area runoff under a drier climate probably accounts for the sediment emplacement inside caves in both areas the mode of emplacement implies bias in the fossil record resulting in fossil assemblages that do not mirror surface faunas limiting palaeoenvironmental reconstruction mass spectrometric u series analysis of speleothem calcite overlaying fossil remains gives minimum ages for fossil deposition these ages confirm the previous view that many of the deposits derive from the late glacial but also show that much older material some 350 000 yr is also present the habitat requirements of critical fossil species such as bats and monkeys strongly suggest that they derive from much wetter periods when forest cover was present in the currently semi arid northern bahia area taphonomy exerts a major control on the diversity and mode of emplacement of cave fossil deposits in eastern brazil and thus detailed sedimentological and hydrological studies coupled with a sound geochronological approach are essential in quantifying the relative importance of each taphonomic processes before faunal and palaeoecological interpretations can be attempted

identifying elements of the plumbing system beneath kilauea volcano hawaii from the source locations of very long period signals summary we analyzed 16 seismic events recorded by the hawaiian broad band seismic network at kilauea volcano during the period september 9 26 1999 two distinct types of event are identified based on their spectral content very long period vlp waveform amplitude decay pattern and particle motion we locate the vlp signals with a method based on analyses of semblance and particle motion different source regions are identified for the two event types one source region is located at depths of 1 km beneath the northeast edge of the halemaumau pit crater a second region is located at depths of 8 km below the northwest quadrant of kilauea caldera our study represents the first time that such deep sources have been identified in vlp data at kilauea this discovery opens the possibility of obtaining a detailed image of the location and geometry of the magma plumbing system beneath this volcano based on source locations and moment tensor inversions of vlp signals recorded by a permanent large aperture broad band network

the cu isotopic signature of granites from the lachlan fold belt se australia abstract this contribution reports our preliminary work to determine cu isotope ratios for various granite rocks and examine the cu isotope systematics within granite suites a chemical procedure modified from marechal marechal c n telouk p and albarede f 1999 precise analysis of copper and zinc isotopic compositions by plasma source mass spectrometry chemical geology 156 1 4 251 273 was used to separate cu from rock matrix quantitative recovery 100 6 1 6 with a low total procedural blank 2 65 0 66 ng for cu has been achieved allowing cu isotopic measurements on samples with as little as 10 ppm cu the cu isotope ratios 65cu relative to nist srm 976 of 32 rock samples ranging from mafic to felsic compositions from 3 batholiths 2 i type 1 s type from the lachlan fold belt in southeastern australia vary from 0 46 to 1 51 most of them cluster around zero with mean values for the i type and s type granites of 0 03 0 15 and 0 03 0 42 2 sigma respectively these data together with cu isotope ratios of two loess samples provide preliminary evidence that the baseline cu isotopic composition of the crystalline part of upper continental crust is close to zero the tight clustering of cu isotope ratios of rocks from the i type suites suggests that high temperature magmatic processes do not produce significant cu isotope fractionation however two granites with abnormally heavy cu isotope signatures up to 1 51 appears to be the result of localized hydrothermal alteration measurable variation in cu isotopic composition of the s type granite may reflect isotopic heterogeneity in the sedimentary source region as a result of redox processes or may be due to hydrothermal overprinting thus cu isotope geochemistry may be a useful tracer for studying hydrothermal alteration and source heterogeneity of granitic rocks

seismic source dynamics of gas piston activity at kilauea volcano hawai i since 2008 eruptive activity at the summit of kilauea volcano hawai i has been confined to the new overlook pit crater within the halema uma u crater among the broad range of magmatic processes observed in the new pit are recurring episodes of gas pistoning the gas piston activity is accompanied by seismic signals that are recorded by a broadband network deployed in the summit caldera we use raw data recorded with this network to model the source mechanism of representative gas piston events in a sequence that occurred on 20 25 august 2011 during a gentle inflation of the kilauea summit to determine the source centroid location and source mechanism we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account we apply a new waveform inversion method that accounts for the contributions from both translation and tilt in horizontal seismograms through the use of green s functions representing the seismometer response to translation and tilt ground motions this method enables a robust description of the source mechanism over the period range 1 10 000 s most of the seismic wavefield produced by gas pistoning originates in a source region 1 km below the eastern perimeter of the halema uma u pit crater the observed waveforms are well explained by a simple volumetric source with geometry composed of two intersecting cracks featuring an east striking crack dike dipping 80 to the north intersecting a north striking crack another dike dipping 65 to the east each gas piston event is marked by a similar rapid inflation lasting a few minutes trailed by a slower deflation ramp extending up to 15 min attributed to the efficient coupling at the source centroid location of the pressure and momentum changes accompanying the growth and collapse of a layer of foam at the top of the lava column assuming a simple lumped parameter representation of the shallow magmatic system the observed pressure and volume variations can be modeled with the following attributes foam thickness 10 50 m foam cell diameter 0 04 0 10 m and gas injection velocity 0 01 0 06 m s 1 gas piston activity occurs in a narrow pipe with diameter of 6 m connecting the halema uma u pit crater to the subjacent dike system the height of the magma column is estimated at 104 m at the start of the sequence based on the period of very long period vlp oscillations accompanying the onset of the gas piston signal based on the change in the period of vlp oscillations and tilt evidence the height of the magma column is inferred to have risen by up to 23 m by the end of the 5 day long sequence a penny shaped crack model of the dike geometry yields effective diameters of 1 2 2 9 km for the east dike and 0 7 km for the north dike the shallower north dike segment is embedded in a relatively weak medium compatible with expected mechanical properties in the hydrothermal environment of this dike

broadband seismic monitoring of active volcanoes using deterministic and stochastic approaches 1 we systematically used two approaches to analyze broadband seismic signals for monitoring active volcanoes one is waveform inversion of very long period vlp signals assuming possible source mechanisms the other is a source location method of long period lp events and tremor using their amplitudes the deterministic approach of the waveform inversion is useful to constrain the source mechanism and location but is basically only applicable to vlp signals with periods longer than a few seconds the source location method assumes isotropic radiation of s waves and uses seismic amplitudes corrected for site amplifications this simple approach provides reasonable source locations for various seismic signals such as a vlp event accompanying lp signals an explosion event and tremor associated with lahars and pyroclastic flows observed at five or fewer stations our results indicate that a frequency band of about 5 12 hz and a q factor of about 60 are appropriate for the determination of the source locations in this frequency band the assumption of isotropic radiation may become valid because of the path effect caused by the scattering of seismic waves the source location method may be categorized as a stochastic approach based on the nature of scattering waves systematic use of these two approaches provides a way to better utilize broadband seismic signals observed at a limited number of stations for improved monitoring of active volcanoes

top down inflation and deflation at the summit of kīlauea volcano hawai i observed with insar 1 we use interferometric synthetic aperture radar insar to study deformation of the summit caldera at k lauea volcano during 2000 2008 which spanned both an east rift zone eruptive event in 2007 and the start of the ongoing summit eruption in 2008 the data set consists of small baseline subset sbas time series generated from 270 acquisitions on three separate beam modes from the radarsat 1 satellite we identify 12 time periods with distinct patterns of displacement that we attribute until late 2003 to secular tectonic driven deformation and from 2004 to 2008 to four different sources in the summit area we model the shallow magmatic system as a spherical reservoir at 1 9 0 1 km depth below the surface to the northeast of halemaumau source 1 and three vertically stacked sills at greater depths in the southern caldera area source 2 at the southern edge of the caldera at 2 9 0 2 km depth source 3 to the south southeast of the caldera at 3 4 0 5 km depth and source 4 south of the caldera at 3 6 0 4 km depth the sequence for filling of and withdrawal from these reservoirs reveals a top down process with sequences of both inflation and deflation initiating in the shallowest source inflation of source 3 is coincident with elevated seismic activity in the upper east rift zone in february 2006 and may 2007 source 4 is elongated toward the southwest rift zone and also shows elevated seismicity that extends toward the southwest rift zone

solid phase control on the mobility of potentially toxic elements in an abandoned lead zinc mine tailings impoundment taxco mexico detailed mineralogical and geochemical investigations were conducted within abandoned pb and zn flotation tailings at el fraile impoundments in taxco guerrero central southern mexico these tailings are divided into an active oxidation zone near the surface an underlying transition zone and an unoxidized zone although these tailings have undergone 30 a of sulfide oxidation the active oxidation zone has only penetrated to a depth of 0 2 m in the settling pond and to 0 6 1 2 m in the dam the oxidation of sulfide minerals and the insufficiency of ph buffering minerals have produced low ph conditions ph 1 9 4 4 and high concentrations of dissolved so42 as and heavy metals so42 1534 10086 mg l 1 fe 1 5 2568 mg l 1 zn 36 7 2435 mg l 1 cd 0 4 30 6 mg l 1 pb 0 01 0 6 mg l 1 cu 0 5 38 2 mg l 1 and as 0 01 164 mg l 1 these concentrations of dissolved constituents are attenuated by a series of precipitation and sorption reactions precipitation of secondary phases gypsum goethite hematite and k jarosite has led to the formation of cemented layers within the active oxidation zone in the tailings dam these cemented layers act as a trap for released potentially toxic elements from the overlying oxidized tailings adsorption and coprecipitation on fe precipitates play an important role in the mobilization and attenuation of zn cd cu and as within the el fraile tailings additionally to the well known ability of fe precipitates to strongly trap as and heavy metals this study shows that precipitation of beudantite pbfe3aso4so4 oh 6 appears to be one of the solid phase controls on the natural attenuation of as and pb and other heavy metals in these tailings

three dimensional volcano acoustic source localization at karymsky volcano kamchatka russia abstract we test two methods of 3 d acoustic source localization on volcanic explosions and small scale jetting events at karymsky volcano kamchatka russia recent infrasound studies have provided evidence that volcanic jets produce low frequency aerodynamic sound jet noise similar to that from man made jet engines for man made jet noise noise sources localize along the turbulent jet flow downstream of the nozzle discrimination of jet noise sources along the axis of a volcanic jet requires high resolution in the vertical dimension which is very difficult to achieve with typical volcano acoustic network geometries at karymsky volcano an eroded edifice dvor caldera adjacent to the active cone provided a platform for the deployment of five infrasound sensors in july 2012 with intra network relief of 600 m the network was designed to target large scale jetting but unfortunately only small scale jetting and explosions were recorded during the 12 day experiment a novel 3 d inverse localization method srcloc is tested and compared against a more common grid search semblance technique simulations using synthetic signals show that srcloc is capable of determining vertical solutions to within 150 m or better for signal to noise ratios 1 for this network configuration however srcloc locations for explosions and small scale jetting at karymsky volcano show a persistent overestimation of source elevation and underestimation of sound speed the semblance method provides more realistic source locations likely because it uses a fixed realistic sound speed of 340 m s explosion waveforms exhibit amplitude relationships and waveform distortion strikingly similar to those theorized by modeling studies of wave diffraction around the crater rim we suggest that the delay of acoustic signals and apparent elevated source locations are due to raypaths altered by topography and or crater diffraction effects implying that topography in the vent region must be accounted for when attempting 3 d volcano acoustic source localization though the data presented here are insufficient to resolve small scale jet noise sources similar techniques may be successfully applied to large volcanic jets in the future

mapping complex vent eruptive activity at santiaguito guatemala using network infrasound semblance pyroclastic laden explosive eruptions from santiaguito volcano guatemala are vented from the 200 m diameter caliente dome summit and result in a superposition of spatially extensive and temporally sustained tens of seconds to minutes acoustic sources a network of infrasonic microphones distributed on various sides of the volcano record distinct waveforms which are poorly correlated across the network and suggestive of acoustic interference from multiple sources presuming the infrasound wavefield is a linear superposition of spatially and temporally distinct sub events we introduce a semblance mapping technique to recover the time history of the spatially evolving sources during successive time windows coincident high resolution video footage corroborates that both rapid dome uplift and individual explosive pulses are likely sources of high semblance infrasound that are identifiable during short 2 s time windows this study suggests that complex and network variable infrasound waveforms are produced whenever a volcanic vent source dimension is large compared to the wavelength of the sound being produced non compact infrasound radiators are probably commonplace at silicic volcanic systems where venting often occurs across a dome surface

stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils and sediments in loot desert central iran abstract stable isotope geochemistry is a unique technique to study the source of salts in soils and sediments in the present research sources of gypsum and other sulfur bearing minerals using stable isotope technique and clay mineralogy were studied in different landforms in loot desert central iran four geomorphic surfaces including neogene conglomeratic formations reg surfaces yardangs and kaleshoor playa surfaces were observed the 34 s values in these geomorphic surfaces ranged between 10 1 12 6 11 2 14 3 11 8 13 8 and 12 1 13 0 respectively the sequential extraction by hcl and hno 3 br 2 was used to find if metal sulfides could have played a role in gypsum formation and is a controlling sulfur source the mean value of 12 9 for 34 s showed that sulfate in the lower cretaceous formation is controlling the s geochemistry decrease of 34 s values during sequential extraction showed some anomalies that could be attributed to the mixing of some soluble sulfate remains by metal insoluble sulfides data on gypsum crystallization water showed a similar trend with isfahan and rafsanjan areas central iran but likely with a cooler temperature at the time of gypsum formation as the 18 o and d were much lighter in the area studied association of large amounts of palygorskite crystals with gypsum and or anhydrite supports that palygorskite was probably formed after the precipitation of gypsum under a high ph and mg ca ratio presence of large amounts of palygorskite in different layers of yardangs showed that the old large loot plain is formed under conditions of post tethyan shallow hyper saline water conditions

variability of the copper isotopic composition in soil and grass affected by mining and smelting in tsumeb namibia abstract the tsumeb mining district namibia is affected by prolonged exposure to multisource contamination related to the mining and smelting of copper ores this study was performed to assess the extent of contamination of topsoil and grass shoots on the basis of the copper isotopic composition compared to an uncontaminated area 65cusoil 0 01 to 0 14 65cugrass 0 17 to 0 03 the soil and grass in the contaminated area are enriched in the heavy isotope 65cusoil 0 13 to 0 76 and 65cugrass 0 15 to 0 64 the 65cugrass soil value exhibits small variations 0 06 to 0 17 due to the variable degree of grass surface contamination depending on the grass washing procedure used the enrichment of soil and grass in the contaminated area in 65cu reflects the cu isotopic composition of old flotation tailings 65cu 0 95 to 1 1 slag 0 11 to 0 55 and particles which originate from the smelting and flue gas cleaning processes 0 15 to 0 49 the long history of mining and processing of copper ores in the tsumeb area and the different isotopic composition of ore concentrates smelted in the local metallurgical plant do not allow assessment of whether the smelting process leads to isotope fractionation of copper however the isotopic composition of cu in the sulfidic feed slag and dust particles sampled over several hours showed that the dust collected from the dusthouse of the local smelter is isotopically lighter 65cu 0 15 relative to the isotopic composition of the charge 65cu 0 28 and 0 44 the results of this investigation demonstrate that the isotopic composition of cu in soils and grasses can be used to assess the intensity of contamination in areas where cu ores are mined and processed provided that the isotopic compositions of the ore processing products are different from the isotopic compositions of the uncontaminated soils and vegetation

characterization of very long period seismicity accompanying summit activity at kīlauea volcano hawai i 2007 2013 abstract eruptive activity returned to the summit region of k lauea volcano hawai i with the formation of the overlook crater within the halema uma u crater in march 2008 the new crater continued to grow through episodic collapse of the crater walls and as of late 2013 had grown into an approximately elliptical opening with dimensions of 160 215 m extending to a depth of 200 m occasional weak explosive events and a persistent gas plume continued to occur through 2013 lava was first observed in the new crater in september 2008 and through 2009 the lava level remained deep in the crater and was only occasionally observed since early 2010 a lava lake with fluctuating level within the overlook crater has been nearly continuously present and has reached to within 22 m of the overlook crater rim volcanic activity at k lauea volcano is episodic at all time scales and the characterization of very long period seismicity in the band 2 100 s for the years 2007 2013 illuminates a portion of this broad spectrum of volcanic behavior three types of very long period events have been observed over this time and each is associated with distinct processes type 1 events are associated with vigorous degassing and occurred primarily between 2007 and 2009 type 2 events are associated with rockfalls onto the lava lake and occurred primarily after early 2010 both of these event types are induced by pressure and momentum changes at the top of the magma column that are transmitted downward to a source centroid 1 km below the northeast corner of the halema uma u crater where the energy couples to the solid earth at a geometrical discontinuity in the underlying dike system type 3 events are not related to surficial phenomena but are associated with transients in mass transfer that occur within the dike system very long period tremor has also accompanied the return of eruptive activity with increasing amplitude associated with hours to months long changes in gas emission rates and summit deformation

copper isotope ratios in magmatic and hydrothermal ore forming environments multi collector inductively coupled plasma mass spectrometry now provides for precise and accurate measurements of cu isotope ratios copper minerals prepared by direct dissolution with and without chromatographic purification yield identical cu isotope ratios within analytic precision of about 0 04x 1r cu isotope ratios have been measured for copper minerals from worldwide magmatic and hydrothermal copper deposits and for several weathered deposits natural variations in d65cu values relative to nbs976 range over 9x chalcopyrite samples from mafic intrusions lie within a narrow range of about 1 5x and most cluster tightly between 0 10xand 0 20x this range lies within the broader black smoker chalcopyrite and iron meteorite ranges and possibly represents a bulk mantle cu isotope ratio most values for hydrothermal native copper from the michigan native copper district also show a narrow range just larger than 0 1xand suggest a common homogeneous source for cu in this large hydrothermal system later copper sulfide and arsenide minerals from this district range to values more than 2x lower than native copper ratios for chalcopyrite and bornite from moderate to high temperature porphyry skarn and replacement deposits as a group and within individual deposits exhibit a broad range of values variations of nearly 1xare observed over distances on the order of 1 m in some cases these variations may result from multiple mineralization events or copper remobilization during retrograde or later hydrothermal activity fractionations between chalcopyrite and bornite where they occur in the same sample or in related samples cluster near 0 4x suggesting equilibrium cu isotope fractionation between them at moderate temperatures in addition weathering of hydrothermal copper minerals produces a wide range of values in secondary copper phases in the supergene environment cuprite typically has higher values than associated native copper therefore redox states appear to exert a significant control over fractionation at low temperatures significant questions remain to be answered before the source of copper in hydrothermal environments can be fully addressed source reservoir cu ratios need to be determined and chemical and physical factors that control cu isotope fractionation must be quantitatively defined d 2003 elsevier b v all rights reserved

magma oscillations in a conduit reservoir system application to very long period vlp seismicity at basaltic volcanoes 2 data inversion and interpretation at kīlauea volcano

shallow degassing events as a trigger for very long period seismicity at kīlauea volcano hawai i the first eruptive activity at k lauea volcano s summit in 25 years began in march 2008 with the opening of a 35 m wide vent in halema uma u crater the new activity has produced prominent very long period vlp signals corresponding with two new behaviors episodic tremor bursts and small explosive events both of which represent degassing events from the top of the lava column previous work has shown that vlp seismicity has long been present at k lauea s summit and is sourced approximately 1 km below halema uma u by integrating video observations infrasound and seismic data we show that the onset of the large vlp signals occurs within several seconds of the onset of the degassing events this timing indicates that the vlp is caused by forces sourced at or very near the lava free surface due to degassing transmitted down the magma column and coupling to the surrounding rock at 1 km depth

10s period volcanic tremors observed over a wide area in southwestern japan unusual seismic oscillations with a period of 10 seconds were observed over a wide area of southwestern japan several lines of evidence indicate that the origin of these 10s waves must be around the aso volcano located in the central part of kyushu island japan although a 10s period is unusually long for a volcanic tremor and no corresponding surface activity at the crater was reported by the local observatory the volcanic origin of the tremor is indisputable a further astonishing aspects of the observation is that there exists a strong correlation between the onset of 10s waves observed remotely and cessation of high frequency 1hz volcanic tremors at the aso volcano the aso volcano appears to be trembling with a 10s period without this having been noticed since seismic monitoring of volcanic activity is limited to high frequencies above 1 hz at the most of the volcanoes in the world long period tremors of the type observed here might be a widespread phenomenon that has been overlooked

cu isotopes and concentrations during weathering of black shale of the marcellus formation huntingdon county pennsylvania usa abstract the complex weathering processes which govern the production of soil from bedrock have proven difficult to understand for many lithologies weathering of black shale is of particular interest because it releases organic carbon and heavy metals as solutes and therefore impacts the health of terrestrial and aquatic ecosystems to understand black shale weathering a geochemical survey was initiated for soils developed on shales of the marcellus formation at a zero order catchment at a satellite site of the susquehanna shale hills critical zone observatory located in jackson corner pennsylvania this formation is an organic and metal rich carbonaceous shale that underlies much of new york pennsylvania ohio and west virginia in this paper we focus on the effects of weathering on variations of cu isotopes in the shale cu concentration data for soil were normalized using ti concentrations to document the mobility of cu relative to bedrock at both the ridgetop and valley floor depletion profiles for cu are documented in the soils the cu in the soils is depleted in 65 cu average 65 cu 0 5 0 2 compared to the parent material average 65 cu 0 03 0 15 consistent with loss of cu from soils the pore waters contain 10 ppb cu on average and are enriched in the heavy isotope average value 65 cu 1 14 0 44 rayleigh fractionation models using the concentration and isotope data of the soils are consistent with pyrite weathering and loss of cu from the ridgetop but downslope transport and cu re precipitation at the valley floor

implications of deflation inflation event models on kīlauea volcano hawaiʻi abstract surface deformation of volcanic areas can reveal information about subsurface magma reservoirs and how magma is transported between them which is an important part of volcano monitoring for hazard mitigation one prominent style of deformation observed at k lauea volcano hawai i is episodic deflation inflation di events which are recorded in surface deformation data and characterized by deflation of the summit region over hours to days followed by rapid re inflation the exact cause of di events is unknown however a commonly proposed explanation is that a temporary blockage occurs in the conduit connecting the south caldera magma reservoir to the shallower halema uma u reservoir thus interrupting the influx of magma this model is investigated by testing the hypothesis that during the deflationary phase of a di event the volume of magma blocked from reaching the halema uma u reservoir is added to the south caldera reservoir using a mass balance approach and deformation modeling the expected deformation tilt pattern was predicted for the reservoirs and compared to tilt observations from 16 large 4 rad magnitude di events between 2010 and 2012 while the predicted tilts due to inflation from the south caldera reservoir are strong enough to be detected this signal is not seen in the tilt observations we also explore the possibility that the blockage occurs below the south caldera reservoir as well as alternative configurations that include a direct connection between the south caldera reservoir and the eruption site none of the simple two reservoir models we test are able to adequately satisfy the observations selected di events show that tilt vectors change in both magnitude and azimuthal direction over the course of deflation we conclude that the portion of the summit storage and plumbing system active during these di events is more complicated than two connected chambers and that it is more likely that these summit reservoirs have their own source conduits connecting in some complex way to the deep magma source

isotopic paleoecology δ13c from mammals from iuiu ba and paleoenvironmental reconstruction δ13c δ18o for the brazilian intertropical region through the late pleistocene abstract stable isotopes of carbon and oxygen of fossil specimens are widely used for paleoecological and paleoenvironmental inferences and there has been an effort to better understand the isotopic paleoecology and chronology of herbivores that inhabited the brazilian intertropical region during the late quaternary in the present work new radiocarbon datings and carbon and oxygen isotopes data for eremotherium laurillardi notiomastodon platensis tapirus terrestris tayassu pecari and mazama gouazoubira are presented from specimens that lived on iuiu county toca fria and jatoba caves state of bahia in the brazilian intertropical region e laurillardi was dated as of 32 ka bp representing the oldest direct dating for this species in the brazilian intertropical region while n platensis was dated as of 25 ka bp fossils of the extant species t pecari m gouazoubira and t terrestris presented radiocarbon ages of 23 ka bp 21 ka bp and 15 ka bp respectively showing that some of these species lived in iuiu during the last glacial maximum according to our analyses t terrestris was the only specialist 13c 11 0 pic3 0 76 ba 0 49 whereas the remaining taxa were generalists mixed feeders 13c 1 3 to 10 0 pic3 0 24 to 0 69 ba 0 58 the paleoenvironment reconstruction in iuiu and other localities in bir during 32 ka bp to 15 ka bp allow us to suggest that the dry arboreal to open savanna habitats rich in grass and shrubs were the most common environment