regional analysis of d velocities from the ray parameters of diffracted p profiles in examining the slownesses of linear profiles of diffracted p arrivals we have discerned regional variations in the compressional velocity structure of d the base of the mantle three methods of determining the slownesses were tested concluding that the waveform cross correlation xc technique is more reliable over a wide range of epicentral distances than methods involving a linear regression through either the first motion or first peak arrival times xc slownesses suggest a statistically conservative range in d average velocities of 3 1 and reveal regions of very fast velocities under asia and the eastern pacific basin and of very slow velocities under the new guinea solomon islands region slownesses were found to correlate well with the tomographic model v3 of morelli and dziewonski 1986 derived from a different technique and data set synthetic seismograms were generated using a summation of spheroidal normal modes and at periods greater than 45 s the diffracted waves show much less variation and are very well modeled by prem

the effect of crystal melt partitioning on the budgets of cu au and ag we have performed five separate sets of experiments to elucidate the effects of magnetite ulvospinel magnetite solid solution and pyrrhotite crystallization on the budgets of au cu and ag at magmatic conditions the experiments were done in both hydrous and anhydrous assemblages at temperatures between 800 and 1050 c pressures from ambient to 140 mpa log f o2 from nno 0 25 to nno and log f s2 from 1 5 to 3 0 nernst type partition coefficients 1 at 800 c in a water saturated assemblage are d agmt melt 2 10 4 2 10 9 d cumt melt 0 82 0 69 d cuusp melt 26 17 d auusp melt 50 31 d cupo melt 174 25 nernst type partition coefficients 1 at 1050 c in an anhydrous assemblage are d cupo melt 200 d agpo melt 58 8 d aupo melt 120 50 the calculated values for d auusp melt and d cuusp melt indicate that the addition of ti to magnetite increases significantly the au and cu scavenging potential of ulvospinel relative to end member magnetite partition coefficients for cu and au between pyrrhotite and melt indicate that a temperature change from 1050 to 800 c in an anhydrous and hydrous assemblage respectively results in no observable change in cu partitioning the calculated partition coefficients are used to model the effect of crystal fractionation on the concentrations of ag cu and au model results suggest that the co crystallization of magnetite and pyrrhotite sequester no more than 2 ag 7 cu and 37 au from the melt over the first 25 solidification if the melt reaches volatile saturation after 25 crystallization the presence of end member magnetite and pyrrhotite do not appear to inhibit the cu au and ag ore potential of the magma ulvospinel magnetite however may reduce the au concentration in the melt by approximately one third relative to its initial value that decreases the overall au available to partition into the volatile phase

reservoir characteristics and their effects on hydrocarbon accumulation in lacustrine turbidites in the jiyang super depression bohai bay basin china abstract a great difference exists between the hydrocarbon charging characteristics of different tertiary lacustrine turbidites in the jiyang super depression of the bohai bay basin east china based on wireline log data core observation and thin section analyses this study presents detailed reservoir property data and their controlling effects from several case studies and discusses the geological factors that govern the hydrocarbon accumulation in turbidite reservoirs the lacustrine fluxoturbidite bodies investigated are typically distributed in an area of 0 5 10 km2 with a thickness of 5 20 m the sandstones of the tertiary turbidites in the jiyang super depression have been strongly altered diagenetically by mechanical compaction cementation and mineral dissolution the effect of compaction caused the porosity to decrease drastically with the burial depths especially during the early diagenesis when the porosity was reduced by over 15 the effect of cementation and mineral dissolution during the late stage diagenesis is dominated by carbonate cementation in sandstones high carbonate cement content is usually associated with low porosity and permeability carbonate dissolution secondary porosity zone and primary calcite dissolution is believed to be related to thermal maturation of organic matter and clay mineral reactions in the surrounding shales and mudstone two stages of carbonate cementation were identified the precipitation from pore water during sedimentation and secondary precipitation in sandstones from the organic acid dissolved carbonate minerals from source rocks petrophysical properties have controlled hydrocarbon accumulation in turbidite sandstones high porosity and permeability sandstones have high oil saturation and are excellent producing reservoirs it is also noticed that interstitial matter content affects the oil bearing property to some degree there are three essential elements for high oil bearing turbidite reservoirs excellent pore types low carbonate cement 15 and average permeability 10 md

extreme alteration by hyperacidic brines at kawah ijen volcano east java indonesia ii metasomatic imprint and element fluxes abstract the hyperacidic brines of the kawah ijen crater lake and banyu pahit river east java indonesia induce an intense alteration on their magmatic host rock this alteration is a proxy for water rock interaction in magmatic hydrothermal systems and associated high sulphidation mineralizing environments as well as for how these systems translate changes in the magmatic system to surface emissions which are used in volcanic hazard monitoring detailed bulk chemical study of altered and unaltered samples shows that alteration is characterised by near complete leaching of all major and trace elements except for pb sn and sb which are progressively enriched pb up to 15 fold absolute enrichment the resulting element release is complementary to the observed changes in composition of the banyu pahit water downstream when corrected for dilution indicating that alteration progressively increases the element load the signature of the change in water chemistry is best explained by complete alteration of fresh rock rather than mature alteration which might be expected given the advanced altered state of the riverbed together with mass balance considerations this indicates that the dominant element source is material falling into the river from the valley flanks the chemical signature of the crater lake is inconsistent with the observed alteration in samples from the hydrothermal system and likewise is best explained by surface input of cations from rocks falling in from the crater walls this indicates that the lake water cation chemistry is not a direct reflection of the underlying magmatic hydrothermal system and that its cation content is therefore not an appropriate monitor of changes in volcanic activity

the age and paleoenvironment of a late miocene floodplain alongside lake pannon rodent and mollusk biostratigraphy coupled with authigenic 10be 9be dating in the northern danube basin of slovakia abstract we present new age constraints for the late miocene volkovce formation of slovakia alluvial facies that accumulated adjacent to lake pannon facies analysis and authigenic 10be 9be dating was undertaken at the bernolakovo and triblavina localities while the latter outcrop also yielded additional small mammal and mollusk assemblages as well as remains of flora the results of seven radiometric dating ages yielded a weighted mean age of 9 65 0 61 ma for the triblavina outcrop and 8 85 0 32 ma for the bernolakovo outcrop the small mammal assemblage at the triblavina outcrop is indicative of the lowermost mn11 zone which in the western european standard definition suggests an age of

climatically driven sedimentary cycles in the late miocene sediments of the pannonian basin hungary abstract by detailed cycle analysis of marginal mostly delta plain facies successions of pannonian sediments the frequency of water level changes of the late miocene pannonian lake hungary can be identified cycle analysis is presented with the object of defining the orbital record preserved in the strata we use the bed thickness as input data for our cycle analysis statistical analysis revealed a slow upward increase of both the frequency and thickness of sand beds in the boreholes resulting from infilling of the lake by a basinward migration of the marginal facies cycles of different order were detected in the sediments the higher order cycles are very close to or are equivalent with the milankovitch climatic cycles 19 ka caused by precession 50 ka caused by obliquity and 400 ka is the longer period of eccentricity the longer 1 m y cycle is very poorly developed here it is probably the analogue of the 3rd order global climatic cycle cycle analysis suggests that one of the main controlling factors of the water level changes of the pannonian lake was high frequency climatic oscillations the long term climatic changes only had a faint impact on the sediments the record of the 3rd order water level changes is very subtle our results show that the water level changes followed the rhythm of that of the eustatic changes but being asynchronous to them i e at high sea level stage the pannonian lake level was low and vice versa

the messinian problem in the pannonian basin eastern hungary insights from stratigraphic simulations abstract earlier studies revealed a prominent unconformity in the messinian stratigraphic record of the lacustrine pannonian basin but it was unclear what factors were responsible for the formation of this unconformity and thus its origin remained controversial the problem was further complicated by the fact that stratal patterns in the messinian varied significantly along the paleo margins of the lake our study introduces quantitative stratigraphic simulations to analyze the role of subsidence sediment supply and lake level changes in the formation of the unconformity and the various architectural patterns that evolved in response to the messinian events the results suggest that a relative lake level fall occurred in the messinian accompanied and followed by tectonic inversion in several parts of the basin since the rate of tectonic subsidence and or uplift varied in space and time the size of the relative lake level fall varied significantly across the basin while various stratal architectural patterns formed in the same time interval the age of the unconformity was estimated based on seismic correlations with paleomagnetic chronozones to be between 5 6 ma which was refined by stratigraphic simulations galeacysta etrusca cysts were found in the unconformity which confirmed its late messinian age the surface is called the intra messinian unconformity imu in this paper seismic interpretations and simulations of stratal architecture led to the formulation of a basin fill model and identification of four stratigraphic architectural patterns related to messinian events including a major lake level fall and coeval and subsequent uplift events in certain parts of the basin

extreme alteration by hyperacidic brines at kawah ijen volcano east java indonesia i textural and mineralogical imprint article kawah ijen volcano located on the eastern tip of java and renowned for its large hyperacidic crater lake poses significant volcanic and environmental hazards to its immediate surroundings crater lake brines seep through the flanks of the volcano to form the banyu pahit river which is used in irrigation downstream resulting in extensive pollution sharply reduced crop yields and health problems the impact on the environment comes mainly from the high element load which is derived from leaching of rocks by the acid fluids and transported downstream our detailed study of water rock interaction in different parts of the kawah ijen system indicates that there are three settings for this alteration the crater lake and banyu pahit riverbed the hydrothermal system below the lake and the solfatara of the active rhyolite dome in all three settings the silicates are leached and altered to amorphous silica in the order olivine glassnan rich plagioclasenortho pyroxenenclino pyroxenenab rich plagioclase in contrast the alteration of titanomag netite is characterised by dissolution in the surficial setting replacement by pyrite and ti oxide in the hydrothermal system and pyritisation ti mobility in the fumarole conduits alteration progresses along crystallographically controlled planes in all phases and shows strong compositional control in plagioclase and titanomagnetite no secondary minerals develop except for minor barite cristobalite pyrite and jarosite this indicates that despite its high element load the waters are undersaturated with respect to most secondary minerals typically produced during alteration of these magmatic rocks by acid chloride sulphate brines and that water rock interaction at kawah ijen is not a sink of elements but rather contributes to the element load transported downstream

sulfur budget and global climate impact of the a d 1835 eruption of cosiguina volcano nicaragua large explosive volcanic eruptions can inject massive amounts of sulfuric gases into the earth s atmosphere and in so doing affect global climate the january 1835 eruption of cosiguina volcano nicaragua ranks among the americas largest and most explosive historical eruptions but whether it had effects on global climate remains ambiguous new petrologic analyses of the cosiguina deposits reveal that the eruption released enough sulfur to explain a prominent ca ad 1835 sulfate anomaly in ice cores from both the arctic and antarctic a compilation of temperature sensitive tree ring chronologies indicates appreciable cooling of the earth s surface in response to the eruption consistent with instrumental temperature records we conclude that this eruption represents one of the most important sulfur producing events of the last few centuries and had a sizable climate impact rivaling that of the 1991 eruption of mount pinatubo

the role of magmatic sulfides and mafic alkaline magmas in the bingham and tintic mining districts utah this paper reports the existence of abundant magmatic sulfides in introduction latite lava vitrophyres and vent facies dikes from the bingham and the eruption of sulfur rich magmas from el chichon tintic districts in central utah these dikes and flows appear to luhr et al 1984 and mt pinatubo westrich gerlach be comagmatic with the ore related monzonite intrusions in addition 1992 in recent years has attracted attention to the limited analytical data suggest that the magmatic sulfides contain most of solubility of sulfur in intermediate magmas and the factors the cu and ag present in the latites magmatic sulfides are preserved potentially responsible for the formation of magmatic only in the least oxidized and least degassed lavas and vitrophyres sulfides and anhydrite however the occurrence of magpetrography of comagmatic dikes and intrusions suggests that matic sulfides in intermediate magmas is not universal resorption and oxidation s degassing of the globules may make many volcanic suites appear to be sulfide unsaturated the metal content available to a magmatic ore fluid minette and inasmuch as magmatic sulfides may sequester chalcophile shoshonite lavas occur in subordinate amounts in the latitic volcanic metals what would their presence signify in magmatic fields associated with latite monzonite intrusions and hydrothermal systems that formed porphyry cu and mesothermal vein ore deposits of the tintic ag pb zn cu au and bingham deposits do they sequester a significant portion of the porphyry cu au mo districts utah the ages chemical and magmatic cu pb zn ag and au thereby restricting modal compositions and field relations of the mafic alkaline lavas metal availability of subsequent ore forming fluids suggest that such magmas mixed and fractionated at shallow crustal we have examined the volcanic rocks from the tintic levels to form the ore related latites and monzonites the unaltered and bingham mining districts fig 1 utah and found mafic alkaline lavas in these districts are some of the most cu rich that almost all of the volcanic units contain magmatic lavas in the great basin province sulfides some quenched dikes and intrusion margins also have preserved magmatic sulfides comparable with those in the volcanic rocks several lines of evidence indicate that the volcanic and intrusive rocks are comagmatic keith et al 1989 1991 waite 1996 the tintic district and east tintic sub district in utah have recorded over

from pull apart to the rifting process the formation of the pannonian basin abstract during the middle and the late miocene intra carpathian basins have developed south and west of the carpathian arc these basins are bounded by normal faults and connected by conjugate shear zones sinistral strike slip fault systems trend ne sw whereas dextral ones trend nw se by means of geometrical analyses of fault system and paleostress tensor determinations it has been possible to consistently reconstruct the succession of tectonic events in the hungarian mountains the two main stages in the structural development of the intra carpathian basins are 1 1 the initiation of pull apart basins along conjugate shear zones in a n s compressional and e w extensional regime and 2 2 the development of these basins in a tectonic regime characterized by a dominant e w trending extension

large scale structure at the core mantle boundary from diffracted waves at the base of the earth s mantle is a region called d which serves as a thermal and chemical boundary layer between the silicate mantle and the liquid iron outer core1 2 tomographic models of mantle compressional wave velocity vp have their worst resolution in d owing to limited ray sampling3 5 but have hinted at large scale lateral variations there here i use a new technique which has its greatest resolution within d to produce a map of the large scale vp variations within d the technique compares the arrival times of waves that have been refracted across and diffracted around the core mantle boundary cmb the diffracted waves travel a long way in d making them excellent probes of this layer and the differential technique removes many effects arising from ray paths outside of d ref 6 the new map provides an image of the continent sized variations at the cmb that is complementary to existing shear wave data7 8 and similarities between the map and projections of ancient subducted lithosphere9 verify previous suggestions10 of a strong coupling between surface plate tectonics and the base of the mantle

role of unconformity bounded units in the stratigraphy of the continental record a case study from the late miocene of the western pannonian basin hungary

water level changes in lake baikal siberia tectonism versus climate relative changes in the level of lake baikal amounting to hundreds of meters in quaternary time are well documented data presented here show that tectonic displacements of the lake outlet or former shoreline features are entirely sufficient to explain these relative lake level changes in contrast the morphology and hydrology of the lake make its level hydrologically insensitive to climate change available evidence indicates that throughout the past several hundred thousand years lake baikal was a dilute through flowing lake controlled by the level of its outlet on the basis of geologic data alone climatic effects on lake level whatever their magnitude are difficult to separate from those caused by active rift tectonism however consideration of 1 the hydrologic budget of the lake and 2 the configuration of the outlet suggests that potential lake level fluctuations due solely to climate change were less than about 2 m

late miocene and pliocene large land mammals and climatic changes in eurasia the fossil teeth of land mammals offer a powerful tool to map the regional details of past climate change in the terrestrial realm we use meanplant eaterhypsodonty molarcrownheight oflateneogenemammallocalitiestomaplatemioceneandpliocenepalaeoprecipitation on the eurasian continent and with higher temporal resolution in europe the results show that the mid latitude drying in eurasia affected thecentral parts ofthecontinentfirst and thatthedrying of western europeafter about7 8maseemstohavecoincidedroughlyintimewith a return to more humid conditions in eastern asia with a return to a drier east and more humid west in the pliocene within europe the hypsodonty based palaeoprecipitation maps suggest that the sequence from mn 9 to mn 12 ca 11 1 6 8 ma was dominated by an east west continental marine humidity gradient which gradually intensified and with a shift of dryer conditions eastwards in mn 12 ca 7 5ma thiswaspartlyoverlainfrommn13onwardsbyanorth southorientedgradient whichpersistedatleasttotheendofthepliocene the maps for both the earliest late miocene mn 9 ca 11 1 9 7 ma and the earliest pliocene mn 14 ca 4 9 4 2 ma show very low regional differentiation possibly suggesting perturbed phases in the evolution of the mammal communities analysis of hypsodonty and dietary structure of the mammalian plant eater community in europe during the entire interval shows that the miocene pliocene boundary was marked by a strong decrease in mesodont species and mixed feeders and an increase in brachydont species and omnivores in this view the shift in the latest miocene from east west to partly north south polarised hypsodonty patterns corresponds mainly to an increase in hypsodont species and grazers it seems probable that the east west gradient was primarily driven by precipitation while the north south gradient would also have been strongly influenced by temperature related effects of humidity

contemporaneous formation of adjacent porphyry and epithermal cu au deposits over 300 ka in northern luzon philippines there is commonly a close spatial relation between porphyry cu au and high sulfidation epithermal cu au deposits throughout the world although a genetic association has not been proven nowhere is this spatial association better seen than in northern luzon philippines where the lepanto epithermal cu au deposit overlies the far southeast fse porphyry cu au deposit both world class orebodies fresh rock and hydrothermal mineral separates yield k ar ages indicating that premineralization and postmineralization volcanism occurred at 2 2 1 8 ma and 1 2 0 9 ma respectively and that the hydrothermal system was active from 1 5 to 1 2 ma k ar ages of alunite from lepanto have the same range as those of hydrothermal biotite and illite from the fse deposit indicating that both epithermal and porphyry mineralization formed from an evolving magmatic hydrothermal system that was active for about 300 ka this temporal relation strengthens the argument for a genetic link between these two styles of ore deposit and has implications for exploration where one style of mineralization is found there is potential for the other nearby

inhomogeneities near the core mantle boundary inferred from short period scattered pkp waves recorded at the global digital seismograph network we analyze short period pkp precursor wave trains recorded at global digital seismograph network stations in the distance range 120 140 to infer the nature of inhomogeneities near the core mantle boundary travel times and particle motions are consistent with predictions of single scattered waves near the cmb the dominant frequencies are around 1 hz the regions best sampled are beneath indonesia north america central africa and south america based on first order scattering theory the characteristics of the wave number spectrum of the structural inhomogeneities are obtained for two hypotheses volume inhomogeneities and topographic irregularities for the range of wavelengths sampled by these data between 10 and 70 km the spectrum of inhomogeneities is best represented by a power law of index 5 3 for volume inhomogeneities and 6 8 for topographic irregularities if the scattering is due only to volumetric inhomogeneities we estimate the strength of the structural variations to be about 0 5 in p wave velocity for a 200 km thick layer if the scattering is due only to topographic irregularities the topography has an rms height of 280 m at present we can not distinguish between these two types of inhomogeneities

alpine tectonics of the pannonian basin the neogene evolution of the pannonian basin is fairly well understood in terms of back arc extension behind the carpathian thrust fold belt this middle miocene holocene basin however is superimposed on an earlier middle eocene early miocene basin traditionally called the paleogene basin of hungary although the paleogene stratigraphy of the basin is well known its structural evolution is not clear however a transtensional origin is assumed analogous to the overlying pannonian basin the existing data set on the paleogene basin can be integrated easily into a compressional basin model other intra carpathian paleogene basins such as the transylvanian and slovenian basins are now considered to be flexural in origin systematic interpretation of reflection seismic data shows that these tertiary basins are superimposed on a cretaceous alpine thrust fold belt the internal geometry of this belt in the basement of the pannonian basin indicates a close relationship to the surrounding mountain belts alps carpathians and dinarides whereas the neogene pannonian basin is in a mature stage of exploration the underlying paleogene flexural basins are much less explored furthermore the cretaceous thrust fold belts should be regarded as frontier areas for future oil and gas exploration efforts

middle to late miocene oxygen isotope stratigraphy of odp site 1085 se atlantic new constrains on miocene climate variability and sea level fluctuations abstract the middle miocene 18o increase represents a fundamental change in earth s climate system due to a major expansion and permanent establishment of the east antarctic ice sheet accompanied by some effect of deepwater cooling the long term cooling trend in the middle to late miocene was superimposed by several punctuated periods of glaciations mi events characterized by oxygen isotopic shifts that have been related to the waxing and waning of the antarctic ice sheet and bottom water cooling here we present a high resolution benthic stable oxygen isotope record from odp site 1085 located at the southwestern african continental margin that provides a detailed chronology for the middle to late miocene 13 9 7 3 ma climate transition in the eastern south atlantic a composite fe intensity record obtained by xrf core scanning odp sites 1085 and 1087 was used to construct an astronomically calibrated chronology based on orbital tuning the oxygen isotope data exhibit four distinct 18o excursions which have astronomical ages of 13 8 13 2 11 7 and 10 4 ma and correspond to the mi3 mi4 mi5 and mi6 events a global climate record was extracted from the oxygen isotopic composition both long and short term variabilities in the climate record are discussed in terms of sea level and deep water temperature changes the oxygen isotope data support a causal link between sequence boundaries traced from the shelf and glacioeustatic changes due to ice sheet growth spectral analysis of the benthic 18o record shows strong power in the 400 kyr and 100 kyr bands documenting a paleoceanographic response to eccentricity modulated variations in precession a spectral peak around 180 kyr might be related to the asymmetry of the obliquity cycle indicating that the response of the dominantly unipolar antarctic ice sheet to obliquity induced variations probably controlled the middle to late miocene climate system maxima in the 18o record interpreted as glacial periods correspond to minima in 100 kyr eccentricity cycle and minima in the 174 kyr obliquity modulation strong middle to late miocene glacial events are associated with 400 kyr eccentricity minima and obliquity modulation minima thus fluctuations in the amplitude of obliquity and eccentricity seem to be the driving force for the middle to late miocene climate variability

amplitudes of diffracted long period p and s waves and the velocities and q structure at the base of the mantle frequency and time domain analysis of amplitudes of long period 20 s p and s waves diffracted around the earth s core and registered at the wwnss and csn stations show that the velocities at the base of the mantle have slightly positive gradients this result substantiates the previous ray parameter study of mula and muller 1980 such velocity gradients at the base of the mantle imply that there is no significant departure from homogeneity and or adiabaticity of the base of the mantle from the rest of the lower mantle as suggested by for example bolt 1972 jones 1977 jeanloz and richter 1979 and doornbos and mondt 1979b in addition to this the q factor for the base of the mantle is found not to be less than 250

sulfur bearing magmatic accessory minerals almost all magmas contain sulfide or sulfate bearing phases in most natural samples the sulfur bearing phase is a sulfide which typically is pyrrhotite fe1 x s or pyrite fes2 although chalcopyrite cufes2 pentlandite fe ni 9s8 sphalerite zns or molybdenite mos2 may be present as well sulfate minerals are rare at magmatic conditions and anhydrite caso4 is the most common other magmatic so4 bearing minerals include the sodalite group minerals hauyne simplified formula na ca 4 8 al6si6 o s 24 so4 cl 1 2 scapolite minerals silvialite ca na 4al6si6o24 so4 co3 and s bearing apatite ca5 po4 3 f cl oh barite baso4 has been mentioned in rare cases marchev 1991 sulfur bearing minerals usually constitute a negligible fraction of the mineral assemblage in magmatic rocks and thus can be classified as accessory minerals the crystallization of sulfide sulfate and s bearing minerals strongly depends on melt composition temperature and pressure and the s speciation in melt which in turn is strongly dependent on the prevailing oxygen fugacity baker and moretti 2011 this volume wilke et al 2011 this volume irrespectively of the low abundance of s bearing minerals the evolution of sulfur in magmas may be evaluated from the occurrence of sulfides and sulfates these minerals are critical for estimating the activity of various sulfur bearing species in magmas and can be used to constrain the oxygen fugacity and the s concentration in the melt e g pre eruptive sulfur concentration in melts the presence of either sulfide or sulfate in silicate melt indicates that the predominant dissolved sulfur species in the melt are s2 or s6 respectively typically one of these species is dominant but there are conditions where s2

rates of delta progradation during highstands consequences for timing of deposition in deep marine systems estimated times required for 24 modern river systems to form a shelf edge delta range from 8 5 ka to 116 5 ka depending on fluvial sediment supply delta width shelf volume and shelf transport rates these values indicate that transport of sand into deep marine systems is likely to be significant during third order highstands of relative sea level factors such as shelf transport dynamics may slow delta progradation while submarine canyons cutting the shelf may reduce the time before deep marine deposition occurs interpreting ancient sand rich deep marine strata as lowstand deposits without sufficient palaeogeographic information may not therefore always be appropriate

paleogeographic evolution of the late miocene lake pannon in central europe abstract the paleogeographic evolution of lake pannon within the pannonian basin is reconstructed with eight maps ranging from the middle miocene to the early pliocene the maps are based on the distribution of selected biozones and specific fossils and on complementary sedimentological and seismic information our reconstruction shows that the history of lake pannon can be divided into three distinct intervals an initial stage with low water level which resulted in isolation from the sea at about 12 ma and might have led to temporary fragmentation of the lake an interval of gradual transgression lasting until ca 9 5 ma and a long late interval of shrinkage and infilling of sediments that persisted into the early pliocene the deep subbasins of the lake formed during the transgressive interval in more basinward locations than the deep basins of the preceding sarmatian age the southern shoreline running parallel with the sava and danube rivers along the northern foot of the dinarides changed very little during the lifetime of the lake while the northern shoreline underwent profound changes

gold and metal enrichment in natural granitic melts during fractional crystallization metal evolution in a composite granitic pluton was tracked by analyzing melt inclusions in 11 quartz samples from 7 zones at the timbarra gold deposit australia we present the first quantitative microanalyses of gold au in granitic silicate melt inclusions using laser ablation inductively coupled plasma mass spectrometry and show how au and other metals become enriched during fractional crystallization in a granite intrusion au was enriched during fractionation from a monzogranite to a highly fractionated alkali feldspar granite similar enrichment behavior for other metals implies that no gold enriched precursor melt is required and fractional crystallization can enrich the au concentration to economic levels the low content of accessory oxides and sulfides the absence of early cl bearing fluids the volatile content in the melt and a prolonged crystallization constitute important factors for extensive metal enrichment during crystal fractionation these characteristics play a crucial role in felsic highly fractionated plutons and their associated deposits such as intrusion related au deposits the gold enrichment during fractionation also implies that au is directly sourced from the granites

melt inclusion record of the conditions of ascent degassing and extrusion of volatile rich alkali basalt during the powerful 2002 flank eruption of mount etna italy 1 two unusual highly explosive flank eruptions succeeded on mount etna in july august 2001 and in october 2002 to january 2003 raising the possibility of changing magmatic conditions here we decipher the origin and mechanisms of the second eruption from the composition and volatile h2o co2 s cl content of olivine hosted melt inclusions in explosive products from its south flank vents our results demonstrate that powerful lava fountains and ash columns at the eruption onset were sustained by closed system ascent of a batch of primitive volatile rich 4 wt basaltic magma that rose from 10 km depth below sea level bsl and suddenly extruded through 2001 fractures maintained opened by eastward flank spreading this magma the most primitive for 240 years probably represents the alkali rich parental end member responsible for etna lavas evolution since the early 1970s few of it was directly extruded at the eruption onset but its input likely pressurized the shallow plumbing system several weeks before the eruption this latter was subsequently fed by the extrusion and degassing of larger amounts of the same but slightly more evolved magma that were ponding at 6 4 km bsl in agreement with seismic data and with the lack of preeruptive so2 accumulation above the initial depth of sulphur exsolution 3 km bsl we find that while ponding this magma was flushed and dehydrated by a co2 rich gas phase of deeper derivation a process that may commonly affect the plumbing system of etna and other alkali basaltic volcanoes

contribution of mafic melt to porphyry copper mineralization evidence from mount pinatubo philippines and bingham canyon utah usa mount pinatubo in the philippines known for its cataclysmic eruption in 1991 hosts several porphyry copper deposits and active geothermal systems an underlying mafic melt supplied much of the sulphur for the dacitic magma and its injection into the dacitic magma chamber triggered the eruption the eruption caused purging of the sulphur rich fluid from the dacite to the atmosphere and extensive fracturing similar events took place at bingham canyon utah site of the largest copper and gold deposit in north america at 38 ma the bingham canyon mineralization took place beneath an active stratovolcano and pyroclastic flows contemporaneous with the mineralization show evidence for magma mingling ascent of mafic melt supplied sulphur and chalcophile elements to the felsic magma which consolidated to form the bingham stock and its underlying magma chamber injections of the mafic melt caused periodic eruptions of felsic magma to form the stratovolcano and deposition of sulphide minerals in highly fractured rocks in and around the stock

using the composition of fluid seepage from the magmatic hydrothermal system of kawah ijen volcano indonesia as a monitoring tool abstract the lake waters of kawah ijen volcano are concentrated hyperacidic brines that obtain their composition from volcanic gases and water rock interaction lake water and hydrothermal fluids seep through the western flank of the volcano where they precipitate gypsum and form the hyperacid banyu pahit river in this contribution we present compositional data from bi weekly samples taken from the banyu pahit between 2015 and 2018 to evaluate whether these fluids can be used to monitor the hydrothermal system and compare the fluids to the record of variability documented by the precipitated gypsum understanding the causal links between variability of the banyu pahit and the magmatic hydrothermal processes operating in the kawah ijen system and establishing a baseline for quiescence are pre requisites to using the river for monitoring fluid samples were analysed at the ijen observatory for so4 cl ratio using baso4 turbidity and agcl gravimetry and subsequently sent for icp ms and icp oes analyses the data shows a first order seasonal variation that can be explained by variable input of neutral groundwater but is underlain by more subtle trends temporally there is a shift in the system from 2015 to 2016 to 2017 when the fluid contains a higher proportion of elements derived from rock alteration the shift occurs at the peak of the rainy season and coincides with a substantial rainfall increase in 2017 compared to 2015 2016 at the start of 2018 there is a marked increase in cu coinciding with a gas burst in march 2018 we suggest that an increased meteoric water input led to an increase in water rock interaction and dissolution of a cu sulphide phase in the hydrothermal system the variability of the fluids over the 3 year sampling period does not exceed that of the longer record preserved by the gypsum precipitates indicating that it is typical for the current style of activity

the structure of the core mantle boundary from diffracted waves diffracted p and s waves pd sd traveling around the core mantle boundary cmb of the earth give us information about the velocity structure and therefore the thermochemistry of d the base of the earth s mantle by examining pd and sdarrivals we determined the apparent ray parameter for different regions at the base of the mantle by comparing the data slownesses to those found from reflectivity synthetic seismograms we were able to quantify d average velocities using these averaged velocities with a thermochemical modeling of lower mantle minerals using a birch mumaghan equation of state we have been able to make chemical and physical inferences as to the causes of lateral variations at the cmb examinations found significant lateral heterogeneity at the base of the mantle amounting to 4 for both p and s velocities these velocities did not always vary in parallel and the poisson ratio varied regionally by almost 6 the most unusual region of the cmb found was under indonesia where velocities 3 slower than the preliminary reference earth models were found adjacent to a region of faster than average velocities these regions currently correspond to areas of core up welling and down welling respectively found by voorhies 1986 which if mostly held in place by core mantle coupling might cause a flux of heat and iron into the mantle making the anomaly both thermally and chemically derived at the cmb under the northern pacific rim the fastest shear velocities were found but the same region yielded slower than average p velocities while the presence of fast shear velocities here would support the idea that we are seeing the cold dregs of mantle convection perhaps continuing down from the north pacific subduction zones the presence of slow p velocities suggests additional complications our thermochemical modeling suggests that the d poisson ratio is very sensitive to variations in the silicate oxide ratio and that a decrease in the amount of perovskite relative to magnesiowustite may play an important role in this region

sulfide breakdown controls metal signature in volcanic gas at kawah ijen volcano indonesia abstract immiscible sulfide liquid is thought to be an important intermediary in volcanic degassing of sulfur and chalcophile elements by concentrating and transferring metals from magma to hydrous fluid here we track the interaction of sulfide liquid with a fluid exsolving from basalt at kawah ijen volcano in indonesia as in many other volcanic systems neither sulfide nor fluid is preserved instead the reaction is recorded in changes in metal and sulfur concentrations in the melt during magma ascent and shows a two stage evolution deep seated progressive breakdown of sulfide during which metal concentrations in the melt are largely controlled by the sulfide followed by fluid melt partitioning controlling metal concentrations at shallow depth once this sulfide has been exhausted present day fumarole gases have similar zn cu pb cu and mo cu ratios to the reconstructed sulfide but are enriched in tl as and sb these enrichments are also observed in melt inclusions in the most recent dacitic deposits at kawah ijen this suggests that the fumarole gases are sourced from a deep degassing sulfide saturated basalt preserved in zn cu pb cu and mo cu ratios which subsequently interact with a shallow dacitic melt that enhances tl as and sb emissions

geochemistry of the magmatic hydrothermal system of kawah ijen volcano east java indonesia samples from kawah ijen crater lake spring and fumarole discharges were collected between 1990 and 1996 for chemical and isotopic analysis an extremely low ph 0 3 lake contains so 4 cl waters produced during absorption of magmatic volatiles into shallow ground water the acidic waters dissolve the rock isochemically to produce immature solutions the strong d and 18 o enrichment of the lake is mainly due to enhanced evaporation at elevated temperature but involvement of a magmatic component with heavy isotopic ratios also modifies the lake d and 18 o content the large so4 s d 23 8 26 4 measured in the lake suggest that dissolved so 4 forms during disproportionation of magmatic so 2 in the hydrothermal conduit at temperatures of 250 280 c the lake 18 o so4 and 18 o h2o values may reflect equilibration during subsurface circulation of the water at temperatures near 150 c significant variations in the lake s bulk composition from 1990 to 1996 were not detected however we interpret a change in the distribution and concentration of polythionate species in 1996 as a result of increased so 2 rich gas input to the lake system thermal springs at kawah ijen consist of acidic so 4 cl waters on the lakeshore and neutral ph hco 3 so 4 cl na waters in blawan village 17 km from the crater the cation contents of these discharges are diluted compared to the crater lake but still do not represent equilibrium with the rock the so 4 cl ratios and water and sulfur isotopic compositions support the idea that these springs are mixtures of summit acidic so 4 cl water and ground water the lakeshore fumarole discharges t 170 245 c have both a magmatic and a hydrothermal component and are supersaturated with respect to elemental sulfur the apparent equilibrium temperature of the gas is 260 c the proportions of the oxidized so 2 dominated magmatic vapor anti of the reduced h 2 s dominated hydrothermal vapor in the fumaroles varied between 1979 and 1996 this may be the result of interaction of so 2 bearing magmatic vapors with the summit acidic hydrothermal reservoir this idea is supported by the lower h 2 s so 2 ratio deduced for the gas producing the so 4 cl reservoir feeding the lake compared with that observed in the subaerial gas discharges the condensing gas may have equilibrated in a liquid vapor zone at about 350 c elemental sulfur occurs in the crater lake environment as banded sediments exposed on the lakeshore and as a subaqueous molten body on the crater floor the sediments were precipitated in the past during inorganic oxidation of h 2 s in the lake water this process was not continuous but was interrupted by periods of massive silica poorly crystallized precipitation similar to the present day lake conditions we suggest that the factor controlling the type of deposition is related to whether h 2 s or silica rich volcanic discharges enter the lake this could depend on the efficiency with which the lake water circulates in the hydrothermal cell beneath the crater quenched liquid sulfur products show 34 s values similar to those found in the banded deposits suggesting that the subaqueous molten body simply consists of melted sediments previously accumulated at the lake bottom

bathymetric and geochemical investigation of kawah ijen crater lake east java indonesia abstract a bathymetric survey of kawah ijen crater lake was conducted by acoustic sounding in 1996 to compare the lake morphology with those measured in 1922 1925 and 1938 and to calculate the present lake volume even though the lake experienced several hydrothermal eruptions the maximum depth became shallower 182 m than before 200 m resulting in a reduced lake volume 3 0 10 7 m 3 fifty two major and minor constituents including rare earth elements and polythionates pt of the lake waters at various depths were determined by icp aes icp ms and hplc respectively these ions except for several volatile elements are taken up by lake fringe through congruent dissolution of pyroclastics of kawah ijen volcano most ions are homogeneously distributed throughout the lake although pt showed a considerable vertical variation rare earth elements ree in the kawah ijen water as well as those from other hyper acidic crater lakes show distribution patterns likely due to the three rock dissolution preferential congruent and residual types and their logarithmic concentrations linearly depend upon the ph values of the lake waters using the pt degradation kinetics data production rates of pt injection rates of so 2 and h 2 s into the lake were estimated to be 114 86 and 30 tons day respectively also travel time of the spring water at the banyupahit riverhead from kawah ijen was estimated to be 600 1000 days through the consideration of decreasing rates of pt molten sulfur stocks containing sn cu bi sulfides and pb barite exposed on the inner crater slope were presumed to be extinct molten sulfur pools at the former lake bottom this was strongly supported by the barite precipitation temperature estimated through the consideration of the temperature dependence of pb chlorocomplex formation

the use of total lake surface area as an indicator of climatic change examples from the lahontan basin abstract variation in the size of lakes in the lahontan basin is topographically constrained river diversion also has played a major role in regulating lake size in lahontan subbasins the proper gage of lake response to change in the hydrologic balance is neither lake depth level nor lake volume but instead lake surface area normalization of surface area is necessary when comparing surface areas of lakes in basins having different topographies to a first approximation normalization can be accomplished by dividing the paleosurface area of a lake by its mean historical reconstructed surface area

shelf edge trajectory and sediment dispersal in a lacustrine setting a case study from qinnan depression bohai bay basin china abstract the oligocene succession of dongying formation in qinnan depression in bohai bay basin has preserved well imaged lacustrine prograding shelf edge scale clinoforms providing a good opportunity to study the relationship between shelf edge trajectory stratal stacking patterns and sediment dispersal and to investigate the effect of controlling factors on sediment dispersal shelf edge trajectories in a lacustrine setting 3d seismic volumes were used for defining seismic units bounding surfaces shelf edge trajectories and sediment dispersal four seismic units have been subdivided and four types of shelf edge trajectories and the associated stratal stacking patterns have been recognized greater volume of sandstone in deep water area tends to develop in seismic units with descending shelf edge trajectory angles and tends be linked to lower shelf edge trajectory angles differential tectonic subsidence rates along the shelf and along strike variation in sediment supply were prime factors controlling lateral variability in trajectory progradation and sediment dispersal the evolution of shelf edge trajectory can be subdivided into three stages local climate might play a major role in controlling lake margin evolution during the first two stages when dry hot weather foster basin floor fan deposition and descending trajectories and humid cold weather hindered the development of basin floor fan and forms ascending trajectories while differential tectonic subsidence could have the dominate role during the third stage when climate signal can hardly be recognized and lateral variability in trajectory angles and sediment supply is most obvious

geographic and temporal patterns in the late neogene 12 3 ma aridification of europe the use of small mammals as paleoprecipitation proxies abstract present day relations between small mammal community structure and rainfall are used to predict late neogene 12 3 ma precipitation patterns in europe and anatolia new proxy methods are developed which include regressions of mean annual and minimum monthly precipitation on diet invertivory index and locomotion habitat arboreality index a series of precipitation maps and a set of regional precipitation curves through time at 1 myr resolution are presented precipitation curves at a higher temporal resolution are constructed for the region of central spain the miocene results show the existence between 12 and 9 ma of a large wet 800 1200 mm yr zone extending from northern spain to the ukraine and characterized by the whole year penetration of large amounts of moisture far into the continent between 10 9 and 5 ma this european temperate wet zone etwz shrinks and or moves northward resulting in diachronous aridification a coeval northward migration of the subtropical high pressure zone shpz is hypothesized which is also consistent with the predicted onset of seasonal summer dryness between 10 and 8 ma the maximum extension of the etwz at 12 9 ma temporally correlates with northern hemisphere cooling suggesting that climate zonation rather than the global amount of atmospheric moisture controlled european climate at this time the main aridification at 9 8 ma could best be explained by a northward extension shifting of the subtropical high pressure zone and a transition towards less zonal circulation processes which ultimately could have been triggered by uplift of the tibetan plateau a temporary increase of precipitation at 7 6 ma is associated with renewed global cooling the lowest precipitation values less than 400 mm yr occur during the pliocene in southern and eastern europe uplift in eastern europe carpathians shrinking of the paratethys could well explain the aridification in this area and the associated sharpening of east west precipitation gradients across the continent

effects of spatially variable accommodation rate on channel belt distribution in an alluvial sequence authigenic 10be 9be based bayesian age depth models applied to the upper miocene volkovce fm northern pannonian basin system slovakia abstract relationships between spatially variable accommodation rate and the distribution of channel belt deposits are important issues in alluvial stratigraphy this segment of sedimentology still records important progress using experimental models and field examples this study focuses on the alluvial stratigraphy of the volkovce fm which was deposited between 9 0 6 0 ma in the northern pannonian basin system and it provides an excellent natural laboratory to study this topic the spatial variability of channel belt distribution was determined in 809 borehole logs drilled to 200 300 m depths while the facies associations were defined on the outcrops a significant variance in channel belt content was observed since it reaches 10 40 of the stratigraphic column in the southwestern part of the study area and only 0 15 in the northeastern portion moreover the transition between the areas of different channel belt distribution is oriented perpendicular to the paleo drainage network axis geochronology was then established by applying the authigenic 10be 9be dating method to three borehole cores the bayesian age depth models used herein proved a decrease in average accommodation rates from 200 m myr to 50 m myr towards the area with

stress induced late stage subsidence anomalies in the pannonian basin abstract subsidence sedimentation and tectonic quiescence of the pannonian basin was interrupted a few million years ago by tectonic reactivation this recent activity has manifested itself in uplift of the western and eastern flanks and continuing subsidence of the central part of the pannonian basin low to medium magnitude earthquakes of the carpathian pannonian region are generated mostly in the upper crust by reverse and wrench fault mechanisms there is no evidence for earthquakes of extensional origin 2 d model calculation of the subsidence history shows that a recent increase in magnitude of horizontal compressional intraplate stress can explain fairly well the observed quaternary uplift and subsidence pattern we propose that this stress increase is caused by the overall europe africa convergence in late pliocene consumption of subductible lithosphere at the eastern margin of the pannonian basin was completed and the lithosphere underlying the pannonian basin became locked in a stable continental frame consequently extensional basin formation has come to an end and compressional inversion of the pannonian basin is in progress

fluid melt partitioning of re mo w tl and pb in the system haplobasalt h2o cl and the volcanic degassing of trace metals abstract the partition coefficients kd x f m of re mo w tl and pb between fluid h 2 o cl and a haplobasaltic melt in the cao mgo al 2 o 3 sio 2 system were measured between 1300 and 1400 c at 1 gpa and fluid chlorine molarities from 7 7 to 27 mol l dissociation of hydroxides added to a trace metal doped oxide powder produced a fluid phase in equilibrium with melt at the run conditions the kd x f m values were determined by mass balance of trace metals added with those determined in glass from the run products at 1300 c and fluid molarity of 7 7 mol l kd re f m 9 8 1 8 kd mo f m 11 8 1 6 kd w f m 3 7 1 6 kd tl f m 4 5 1 4 and kd pb f m 2 4 1 8 both mo and re were shown to partition most strongly into the fluid at all temperatures and fluid chlorinities at 1400 c kd pb f m and kd tl f m were the only elements showing any correlation with fluid chlorinities at 1400 c re and mo completely partitioned into the fluid and thus our calculated kd re mo f m are minima controls on fluid melt partitioning are explored in detail calculated values of kd re tl pb f m were combined with the diffusivity of these elements in a 1 d bubble growth model to evaluate the change in metal concentrations and metal ratios expected during the degassing of magma the model results were compared with emanation coefficients for trace metals from natural volcanoes the magnitudes of the modeled re tl and re pb in fluids using the diffusivity and partitioning values at 1300 c and the lowest fluid chlorinities were less than that observed from their emanation coefficients

phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration abstract progress in understanding the structural evolution of the pannonian basin is reported this has been driven by the application of seismic stratigraphy constrained by magnetostratigraphic data and the recent release of a great amount of hydrocarbon exploration data this has led to a redefinition and better understanding of the syn rift period and style of rifting in addition a complex structural evolution history during the post rift phase has been recognized two compressive events are defined one in the early stage and another in the late stage of evolution the importance of these findings for hydrocarbon exploration includes an improved knowledge of the timing of trap formations and a possible explanation for remarkably variable reservoir pressures in pools of the great hungarian plain

water level changes and their effect on deepwater sand accumulation in a lacustrine system a case study from the late miocene of western pannonian basin hungary major deepwater sand accumulations are known to be connected to sea level lowstands in marine basins due to the relative lack of accommodation space on the shelf this model was tested for the late miocene lake pannon a large endorheic lake depositing a sedimentary succession up to 3 4 km thick the progradation of the shelf between 9 7 and 6 ma was tracked along a 2d seismic network the shelf edge trajectory indicates continuous moderate lake level rise between 9 7 and 9 ma this is followed by alternating intervals of quasi steady and rapidly rising relative lake level with a period of ca 250 ky however due to the lack of significant lake level drops no third order sequence boundary was identified in the studied time span 9 7 6 ma the sand ratio of the deepwater deposits does not show strong correlation with these lake level changes moreover the units deposited under rising lake level conditions generally contain slightly larger proportion of sand these features can be explained by the climatic origin of water level rises increasing precipitation enhances not only water inflow but also sediment influx which can overwhelm the well known effect of accommodation space on the sand transport toward the deep water the results suggest that shelf margin trajectory might not be an efficient tool for predicting deepwater accumulations of sand in endorheic lacustrine basins

slab diffraction of s waves seismograms are synthesized by superposition of gaussian beams for teleseismic s waves radiated by deep focus earthquakes located within the zone of high seismic velocities that define a descending lithospheric slab the s wave synthetics demonstrate a phenomenon of slab diffraction that acts to lengthen the apparent pulse width of the s wave low frequency energy leaks out of the slab and travels to the receivers along paths in the lower velocity region surrounding the slab seismograms synthesized in fully three dimensional models of slab structure show that slab diffraction strongly depends on the azimuth of the receiver with respect to strike of the slab slab diffraction lengthens the pulse width of s waves in the entire azimuthal range on the dipping side of the slab as the azimuth approaches the strike of the slab the diffracted phase may evolve into a higher frequency impulsive phase which arrives after the minimum time arrival some slab models predict the slab phase to become a superposition of multipathed ray theoretical arrivals as the azimuth approaches the strike of the slab as the azimuth varies through the strike of the slab toward the side opposite the direction of dip the slab phase is rapidly extinguished rapid variations in the complexity of s waveforms recorded along azimuths parallel to the strike of the slab are consistent with the predictions of synthetic seismograms evidence of slab diffraction in the s waveforms of the deepest focus earthquakes supports the hypothesis of slab penetration beyond 650 km depth broadband s waveforms from deep focus earthquakes in the kuril kamchatka slab suggest that this slab penetrates below 650 km and that it may suffer some distortion in shape and advective thickening below this depth

birth life and death of the pannonian lake abstract the miocene pliocene pannonian lake formed in an extensional basin system behind the compressional arc of the carpathians its size and depth were comparable to those of the caspian sea subsidence began in middle miocene times forming deep pelagic basins separated by reef bearing ridges clastic influx filled the marginal basins during middle miocene time prograding deltas dissected the lake and completed the infilling of the basin system by the end of the pliocene basin plain prodelta delta front delta plain beach fluviatile and marsh environments can be recognized terminal miocene uplift of the carpathians isolated the pannonian region from the rest of paratethys the subsequent decrease of salinity resulted in the evolution of an endemic freshwater mollusc fauna rich nutrient influx from rivers supported high organic productivity dinoflagellates diatoms nannoplankton foraminifers ostracods etc yielding organic rich sediments preservation of organic matter was helped by a stratified water column and oxygen deficient bottom conditions deep burial continuing subsidence and high geothermal flux due to an extremely thin crust led to the formation of commercially exploitable oil and gas accumulations shallow lacustrine zones of basin margins provided suitable environments for a rich congeria melanopsis mollusc fauna wave action on beaches produced commercially exploitable pure quartz sand deposits taxodium and alnus forests flourished around the lake producing enormous lignite deposits besides a rich land snail and mammal fauna prehominids lived in the forests there was a warm temperate climate with probably frostfree winters basaltic volcanoes overlooked the landscape and maars hosted minor lakes with rich algal flora forming oil shale the catchment area included most of the carpathians and parts of the apls and dinarides the positive water balance resulted in a supposed overflow in the southern margin supplying exotic fauna to the south carpathian and dacian basins of the eastern paratethys the pannonian lake was completely filled by the end of pliocene recent lakes in the carpathian basin are not descendants of it

thick turbidite successions from supply dominated shelves during sea level highstand emphasis on the association between relative sea level lowstand and the formation of sandy deep water fans has tended to downplay the significance of high sediment supply and its potential to create deep water fans even during sea level highstands the lance fox hills lewis shelf margin in southern wyoming suggests that high supply was critical in causing the accretion of this moderately wide maastrichtian shelf margin at a minimum rate of 47 8 km m y and the generation of large sand rich fans during every shoreline regression across the shelf it is surprising that fans developed from shelf margin clinoforms that show systematically rising shelf edge trajectories proxy for rising relative sea level as well as from those that show flat trajectories stable to falling relative sea level however the latter producing more sediment bypass resulted in bigger and thicker fans whereas the former produced somewhat smaller and thinner fans we term the former highstand fans and suggest caution in using the lowstand model for high supply systems

the magnetite crisis in the evolution of arc related magmas and the initial concentration of au ag and cu the association of large au cu ag ore deposits with convergent margins is commonly attributed to the higher content of chalcophile elements in the parental magmas generated at subduction zones compared with mid ocean ridges we present new geochemical data for arc like relatively oxidized mantle derived basalt to rhyolite magmas from the pual ridge and vicinity eastern manus basin which show that the initial abundances of base and precious metals in the parental basalts are similar to those of mid ocean ridge basalt morb the contents of au cu and ag are built up in the evolving pual ridge liquids to levels considerably in excess of those in morb because unlike morb they are not saturated in a sulfide phase which is a consequence of their being more oxidized than morb the behaviour of s during the evolution of the pual ridge magmas is obscured by late stage so2 loss during eruption but we show that it may be inferred by using se as a proxy because this element follows s closely during magmatic evolution except it is not lost during low pressure near sea floor degassing the onset of magnetite fractionation at 60 wt sio2 and an mg number of 40 is accompanied by an abrupt decrease in the contents of au cu and ag previously attributed to separation of cu au rich fluid which is also shown by se implying that magnetite fractionation triggers sulfide saturation petrological modelling reveals that the amount of magnetite fractionation involved is sufficient to convert most of the s originally dissolved in the magma as sulfate so42 to sulfide s2 triggering saturation in a cu rich sulfide phase tentatively identified as bornite cu5fes4 this sulfide phase sequesters au and ag elements with the same valence as cu in sulfides but not other potentially chalcophile elements such as ni re and pt which suggests that the phase is crystalline rather than an immiscible sulfide melt the relatively high contents of cu and au characteristic of evolved convergent margin magmas requires no enrichment from subducted material instead the association of major cu au deposits with convergent margin magmatism results specifically from the process of magmatic evolution under oxidizing conditions this same property also leads to early magnetite fractionation triggering the abrupt saturation in the cu rich sulfide hence the easily recognizable trend of magmatic evolution under oxidizing conditions i e the sharp drop in chalcophile element concentrations may be an exploration guide to economic au ag cu provinces or a crucial pre enrichment step in the formation of such deposits the decrease in p2o5 and sr at the same stage in the fractionation sequence 60 wt sio2 indicates that saturation in apatite is concomitant with magnetite sulfide saturation in the eastern manus basin

late miocene washhouse climate in europe abstract we present two eight million year long proxy records of precipitation for southwest and central europe covering the middle to late miocene 5 3 13 ma at a temporal resolution of about 60 kyr and 150 kyr respectively the estimates of precipitation are based on the ecophysiological structure of herpetological assemblages amphibians and reptiles from 13 0 ma until about 9 ma both records show a similar trend evolving from a long dry period 13 11 ma into a washhouse climate 10 2 9 8 ma characterized by global warm conditions and several times more precipitation than present the transition from washhouse to a dryer climate between 9 7 and 9 5 ma and the concomitant cooling episode appear to have triggered a severe biotic event known as the vallesian crisis which included the extinction of hominoids in western europe a second washhouse period 9 0 8 5 ma coeval with a global warm episode was unprecedentedly intense in southwest europe but less pronounced in central europe from 8 ma onward a divergence in the two precipitation records is observed with southwest europe staying wetter and central europe becoming dryer than present both precipitation records are combined into a common run off curve as a measure of the relative intensity of the hydrological cycle for moderate latitudes of continental europe the run off curve shows a remarkable positive correlation with atlantic deep water temperatures from ceara rise by lear et al 2003 which are significantly higher up to 3 c during the two washhouse periods and show no other positive excursion of comparable magnitude we discuss potential links and the role of the coeval temporary restriction of the central american seaway on ocean and atmosphere circulation

spectroscopic ftir imaging of water species in silicic volcanic glasses and melt inclusions an example from the izu bonin arc recent advances in ftir spectroscopic imaging allow images of elements or molecules such as water to be constructed on samples over a large sub mm area the imaging detector consists of 64 64 channels providing 4096 individual spectra simultaneously collected over a spectral range of 4000 900 cm 1 the wavelength range includes measurable peaks for water and carbon species making it ideal for the analysis of volcanic glasses particularly melt inclusions advantages of spectroscopic imaging include high spatial resolution 5 m allowing the analysis of melt inclusions too small to be analysed by other micro ftir techniques and the acquisition of high definition in situ images of the materials analysed the technique is applied to the analysis of water species concentrations and distribution in silicic volcanic glasses from sumisu caldera and torishima volcano in the izu bonin arc to test the application of imaging to geologic samples results obtained are found to be comparable to analyses by conventional micro ftir techniques withsimilarprecision butgreaterspatialresolution groundmassglassesfromsumisucalderadacitescontain1 2 1 4wt h2o and an obsidian sample from torishima volcano contains 0 2 wt h2o consistent with water saturation at their respective pressures of eruption melt inclusions in honeycomb plagioclase from sumisu caldera have higher water contents 1 02 1 38 wt h2o than inclusions from torishima volcano plagioclase 0 22 0 41 wt h2o despite evidence for many inclusions being trapped wholly within honeycomb plagioclase low water contents similar to those of the groundmass glasses suggest that the inclusions underwentwaterlossbydegassingand or diffusion alternatively iflowwatercontents ofthemeltinclusionsreflectthecompositionof the magma at the time of entrapment then the magma can be constrained as having originated from a water poor source despite the ambiguity in initial water contents of the magma the anhydrous mineral assemblage of all sumisu caldera and torishima silicic rocks indicates anoriginfrom awater poorsource consistent withmodelsfor partialmeltingofwater poor mafic lower mid crust ratherthan melting of wet lower mid crust or differentiation from basaltic magmas

the mechanism of the deep bolivia earthquake of june 9 1994 we analyzed the iris broad band seismograms for the june 9 1994 bolivia earthquake the largest deep focus earthquake ever recorded we inverted the record sections with a duration of 330 sec which include p pp and sp phases and obtained a dip slip mechanism dip rake strike 13 4 1 or 89 103 95 with a scalar moment of mo 2 9 10 21 nm mw 8 2 this mechanism is similar to that obtained from long period 175 to 250 sec rayleigh and love waves 83 100 90 mo 3 0 10 21 nm mw 8 3 the main rupture was preceded by about 10 sec by a cluster of smaller events with a total moment of 1 2 10 20 nm mw 7 3 the main rupture starts at about 20 km east or northeast of the initial break and propagates horizontally in the east to northeast direction the source duration is 40 sec and the rupture dimension is about 40km if a fault area of 40 40km is assumed the stress drop is 110 mpa an inversion of body waves p pp and sp with 6 basis moment tensors yielded a best fit solution with a 10 implosive component this result is of marginal significance and its confirmation would require more detailed information on the structures near the source region pp bounce points and stations the observed amplitude of the radial mode 0s 0 1226 sec is consistent with a double couple model with less than 2 isotropic component

on the observation of high frequency pkikp and its coda in australia the seismic phase pkikp reflected from the inner core and its coda give information on the short scale heterogeneities at and below the inner core boundary icb of the earth we have collected pkikp recorded at short distances 45 at broadband stations in australia and at the warramunga seismic array wra despite potential complications from a dual passage through d pkikp is frequently observed on single traces in the frequency band 1 5 hz pkikp usually has a sharp onset but sometimes its waveforms have multiple pulses separated by times of the order of 1 s at wra the coda of pkikp initially decays very rapidly after the main pulse thereafter its amplitude is nearly constant and more than three times smaller than pkikp with duration longer than 200 s our observations differ from those of nature 404 2000 273 275 at rather greater distances who found that the coda is larger than pkikp and increases slowly we suggest that the pkikp coda is generated near the inner core boundary by complex reverberation effects rather than scattering through the volume of the inner core 2004 elsevier b v all rights reserved

late miocene to early pliocene chronostratigraphic framework for the dacic basin romania abstract new magnetostratigraphic results and calcareous nannofossil data of seven sections in the dacic basin of southern romania covering the latest maeotian to early romanian time span 6 4 4 0 ma allow a correlation with the current astronomical polarity time scale this establishes a chronological framework for the pontian and dacian stages of the paratethys and facilitates to correlate the paratethys stages with those of the mediterranean the maeotian pontian boundary is estimated at 6 15 0 11 ma within subchron c3an 1n while the age of the pontian dacian boundary is 5 30 0 1 ma within subchron c3r the odessian portaferrian and portaferrian bosphorian substage boundaries can be placed at about 6 0 and 5 6 ma at the base and near the end of chron c3r respectively consequently the pontian stage has a duration of approximately 0 85 myr and is coeval with the upper half of the messinian stage the base of the dacian stage corresponds to the onset of the pliocene and is coeval with the pontian kimmerian boundary of the euxinic black sea basin the dacian romanian boundary is recorded either at 4 58 0 05 ma in subchron c3n 2n nunivak or at 4 25 0 05 ma in subchron c3n 1n cochiti the length of the dacian stage is therefore about 0 7 myr or approximately 1 ma the transition of the getian into the parscovian substage can be dated at 4 83 ma within subchron c3n 3n sidufjall or at 4 55 ma within subchron c3n 2n nunivak the occurrence of calcareous nannofossil assemblages in the lower portaferrian and near the portaferrian bosphorian transition belonging to the upper part of the discoaster quinqueramus nn11 zone and in the middle bosphorian belonging to the amaurolithus tricorniculatus nn12 zone indicates the presence of ephemeral marine connections between the paratethys basin and the mediterranean during the late messinian another marine influx inferred from nannofossil species characteristic of the nn12 zone and found in lower dacian sediments near the top of subchron c3n 4n thvera post dates the basal pliocene transgression of the mediterranean basin

latest pannonian and quaternary evolution at the transition between eastern alps and pannonian basin new insights from geophysical sedimentological and geochronological data the transition zone between eastern alps and pannonian basin is a key area for the investigation of the interplay between regional uplift local tectonic subsidence and depositional environment our study area the western margin of the little hungarian plain is characterized by gentle hills plateaus and depressions of which several are filled by lakes including one of austria s largest and shallowest lakes lake neusiedl geological investigation is hampered by the scarcity of outcrops and thus direct observation of sedimentological or structural features is difficult despite a long research history in the area a consistent landscape evolution model considering all relevant constraints is lacking so far in this study we apply multidisciplinary methods to decipher the complex tectonic and fluvial depositional evolution of the region local data from shallow lake drilling and seismic investigation are combined with regional data from industrial seismics and core data to gain new insights into the latest pannonian late miocene and quaternary evolution shallow lake seismic data show the erosionally truncated pannonian sediments dipping and thickening toward southeast toward the modern depocenter of the little hungarian plain overlying quaternary fluvial sediments show a very similar thickening trend except for the area on the plateau north of the lake indicating ongoing subsidence in major parts of the basin drill cores from locations along the lake seismic lines were analyzed concerning their age mineralogy and heavy minerals and compared with outcrop samples from the surrounding plains and the plateau to derive indications on sediment provenance a key observation is the apparent lack of a significant gravel layer on top of the tilted pannonian sediments beneath lake neusiedl small scale faults can be observed in the lake seismic sections along with key sedimentary features significant differences of the current elevation of the top pannonian between the surrounding plains and the plateau indicate post pannonian normal faulting which is a key process in shaping the present day morphology of the region luminescence ages of samples from the quaternary fluvial gravels on top of the pannonian sediments are a significantly higher 300 ka compared to the gravels in the plain 102 11 and 76 8 ka suggesting ongoing tectonic subsidence

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

tectonic versus climatic control on the evolution of fluvio deltaic systems in a lake basin eastern pannonian basin abstract the pannonian basin is a back arc lake basin situated inside the central european carpathian loop surrounded by the orogenic belts of the eastern alps carpathians and dinarides integrated stratigraphical and sedimentological research reported here focuses on palaeogeographical evolution and particularly the response of the fluvio deltaic systems to climatic and tectonic controls in the late neogene sedimentary succession in the eastern part of the pannonian basin this work has been carried out using subsurface data including regional composite seismic profiles and well logs dip sections were studied to define the stratigraphical architecture depositional environments and sequence stratigraphy and to interpret the sedimentary evolution of the area the eastern pannonian basin is characterized by sediment input from the north east which was one of the main routes of the fluvial deltaic systems entering and progressively filling lake pannon from 11 6 2 6 ma the formations studied were deposited in environments that ranged from the deep water basin plain slope delta front and coastal plain to alluvial plain causing the deposition of characteristic lithofacies associations and characteristic biofacies these form laterally continuous lithofacies units that can be correlated through the basin all depositional facies units have considerable thicknesses 300 1000 m in the deepest parts of the sub basins sequence stratigraphical interpretation was carried out correlating 3rd and 4th order sequences ma to ky in range through a regional composite seismic profile network in the dip direction stratigraphical architecture and sedimentary facies indicate that the 3rd order cycles were controlled by tectonic driving forces while 4th order cycles were probably driven by large scale climatic changes within the milankovitch band in the 3rd order time interval pa 3 between 9 1 and 6 8 ma a major tectonostratigraphic event occurred highlighting the role of strike slip faulting related transtensional subsidence in the derecske sub basin superimposed on the regional post rift thermal subsidence of the eastern pannonian region the substantial base level fall at sb pa 4 at 6 8 ma over 200 m perhaps amplified by subsequent tectonic movements can be related to the onset of a new compressional phase of structural evolution in the basin

geochemistry mineralogy and chemical modeling of the acid crater lake of kawah ijen volcano indonesia the kawah ijen volcano with a record of phreatic eruptions has its 1000 m wide crater filled with a lake that has existed for at least one century at present the lake waters are hot t 37 c strongly mineralized tds 105 g l and extremely acidic ph 0 4 by its volume the javanese lake is probably the largest accumulation in the world of such acidic waters mineralogy of the suspended solids within the lake waters suggests that concentrations of si ca ti and ba are controlled by precipitation of silica gypsum anatase and barite lake sediment is composed of chemical precipitates with composition similar to the suspended solids thermodynamic calculations predict that the lake waters have reached equilibrium with respect to cristobalite barite gypsum anglesite celestite and amorphous silica in agreement with the analytical observations significant concentrations of ferric iron suggest that the current lake waters are fairly oxidized sulfides are absent in the water column but are always present in the native s spherules that form porous aggregates which float on the lake the presence of native s provides direct evidence of more reduced conditions at the lake floor where h 2 s is probably being injected into the lake with progressive addition of h 2 s to the acid waters native s pyrite and enargite are theoretically predicted to be saturated reactions between upward streaming h 2 s bearing gases discharged by subaqueous fumaroles and metals dissolved in the acidic waters could initiate precipitation of these sulfides a model of direct absorption of hot magmatic gases into cool water accounts for the extreme acidity of the crater lake results show that strongly acidic sulfate rich solutions are formed under oxidizing conditions at high gas water ratios reactions between the acidic fluids and the ijen andesite were modeled to account for elevated cation concentrations in lake water current concentrations of conservative rockforming elements are produced by dissolution of approximately 60 g of andesite per kg of acid solution complete neutralization of the acid lake waters by reaction with the wallrock produces a theoretical alteration assemblage equivalent to that observed in volcano hosted acid sulfate epithermal ore deposits

downstream composition changes of acidic volcanic waters discharged into the banyupahit stream ijen caldera indonesia abstract the crater lake of kawah ijen volcano contains extremely low ph we discuss the downstream composition changes affecting the banyupahit waters by using stable isotope chemical and mineralogical data collected from sites along the stream length the saturation of the stream waters with respect to minerals was evaluated with solveq and wateq4f and compared with the geochemical observations an aluminous mineralogy alunogen pickeringite tamarugite and kalinite develops in the upper part of the banyupahit due to concentration of the headwaters by evaporation downstream attenuation of dissolved element concentrations results principally from dilution and from mineral precipitation the stream ph changes from 0 at the source to 4 close to the mouth the d and 18o values and the relative so4 cl f contents of the banyupahit waters indicate that the tributaries are mostly meteoric dissolved so4 in the acidic stream come only from the crater lake seepages and are not involved later in microbially mediated reactions as shown by their 34s and 18o values re equilibration of the stream so4 oxygen isotope composition with h2o from tributaries does not occur calcium sio2 al fe k and so4 behave non conservatively in the stream waters gypsum silica amorphous or poorly ordered a basic aluminum hydroxysulfate basaluminite k jarosite and amorphous ferric hydroxide may exert a solubility control on these elements along the entire stream length or in certain stream sections consistent with the thermochemical model results downstream concentration trends and mineral saturation levels suggest that precipitation of sr pb rich barite and celestite consume ba sr and pb whereas dissolved cu pb and zn may adsorb onto solid particles especially after the junctions of the acidic stream with non acidic rivers we calculated that significant fluxes of so4 f cl al sio2 ti mn and cu may reach the irrigation system possibly causing serious environmental impacts such as soil acidification and induration

present seismic evidence for a boundary layer at the base of the mantle to improve the global coverage needed in investigating the observational consequences of boundary layer models the existing data set has been extended with long period diffracted p and sh from the sro network and short period diffracted p from the norsar array it was found that on average the amplitude decay of diffracted sh is relatively small in accordance with the majority of previously published wwssn data and consistent with the observed weakness in dispersion of this phase these results in combination with the apparent absence of anomalously high dt d can be explained by a relatively thin 100 km low velocity zone at the base of the mantle long period diffracted p wave data probably lack the required resolution for detecting a relatively thin transition zone such a zone with relatively low velocity is allowed by an average of travel time and amplitude data across the core shadow boundary and appears to be required by the norsar observations of short period diffraction far into the shadow however recent results of individual short period p wave studies pertaining to geographically limited regions only including also the norsar observations are partly conflicting unless lateral variations exist on balance current thermal models appear to be consistent with but not required by the present seismic evidence

critical differences in sediment delivery and partitioning between marine and lacustrine basins a comparison of marine and lacustrine aggradational to progradational clinothem pairs

origin of short period signals following p diffracted waves a case study of the 1994 bolivian deep earthquake abstract seismograms of the june 9 1994 bolivian deep earthquake recorded at epicentral distances from 100 to 122 show a train of signals with predominant frequencies between 1 and 2 hz after the arrivals of short period diffracted p waves p diff we investigate the origin of these signals following p diff by analyzing a total of 20 records from the iris broad band network and the short period network of new zealand the arrivals of late signals continue for over 100 s that is two times longer than the estimated source duration of this event subsequent aftershocks which cause the following signals are not expected from the long period records these results indicate that the long continuation of short period signals is not due to the source complexities the signals following p diff have small incident angles and their spectra show peaks at about the same frequencies these characteristics of the following signals exclude the possibility that their origin is shallow structure such as the heterogeneities beneath the stations or upper mantle p diff propagates a long distance within the heterogeneous region near the core mantle boundary we conclude that the short period signals following the main p diff are scattered waves caused by small scale heterogeneities near the core mantle boundary

neogene sequences in the pannonian basin hungary abstract the rifting in the extensional pannonian basin occurred in the middle miocene the subbasins within the pannonian system formed under the control of expansional tectonics during this time sequence stratigraphic analysis on well logs revealed a single third order synrift sedimentary sequence developed due to tectonically enhanced eustatic sea level change in shallow marine environments the pannonian basin became an isolated lake by its postrift phase during the middle late miocene boundary the first postrift sequence formed under peculiar conditions when the basin lost its marine connections and simultaneously a considerable differential subsidence began the large volume of freshwater input supplied by rivers and the rapid subsidence of the basement caused the basin to be a deep freshwater lake the lacustrine postrift infill was studied by sequence stratigraphy using seismic reflection well log and magnetostratigraphic data numerous unconformities can be revealed which represent relative lake level fluctuations of different magnitudes the water level and volume of the large inland lake was very sensitive to different effects the most important ones are lake water budget sediment influx and differential subsidence of the basement the style of extension and sedimentation show differences with respect to passive continental margins that are reflected in the sedimentary architecture a significant third order water level change has been discovered in the eastern part of the pannonian basin while the western side did not experience such a great change in lake level this fact gives credit to the view of different interplay of lake level influencing effects in different areas of the basin this major third order lake level change has been age dated using magnetostratigraphy and a very close match was found with the age of the mediterranean salinity crisis the pannonian basin offers the possibility to study the infilling style and stratigraphic evolution of an inland rifted basin detailed sequence analysis allows the recording of the apparent sea lake level motion which can be compared to those observed in the surrounding seas further tectono stratigraphic evaluations of the pannonian basin may reveal hidden facts on the nature of lake level fluctuations and contribute new data to the discipline of sequence stratigraphy

late miocene climate in the circum alpine realm a quantitative analysis of terrestrial palaeofloras abstract selected mega and microfloras from central and southern europe have been analysed for the time interval tortonian pannonian mn 9 12 with the coexistence approach to obtain quantitative palaeoclimate data the results give a geographically differentiated picture of the late miocene climate in the circum alpine area spatial patterns are presented in maps for mean annual temperature temperature of the coldest month temperature of the warmest month mean annual precipitation and mean annual range of temperature the obtained data show an overall warm humid and homogenous climate with very low latitudinal and longitudinal gradients there is no indication of a mediterranean type of climate palaeogeographic influences on climate patterns are evident the pannonian lake caused mild winters and a lower seasonality of temperature in the pannonian basin

third order middle miocene early pliocene depositional sequences in the prograding delta complex of the pannonian basin abstract few studies exist in the geologic literature that show the distribution of seismic facies and depositional sequences within a lacustrine basin the pannonian basin of central europe offers a unique opportunity to evaluate the influence of the eustatic signal on lacustrine deposition seismic stratigraphie and sedimentological studies indicate that the middle miocene early pliocene infill of the transtensional pannonian basin was formed by large delta systems systematic sequence stratigraphie analysis of 6000 km of reflection seismic data and more than 100 hydrocarbon exploration wells in hungary allowed the identification of twelve third order sequence boundaries in the late neogene sedimentary fill this number of depositional sequences corresponds to that of the published global eustatic curve for this time period furthermore based on magnetostratigraphic and radiometric data the ages of these depositional sequences can be tentatively correlated with the global eustatic curve the pannonian basin became isolated from the world sea at the sarmatian pannonian 11 5 ma boundary and formed a large lake the stratal patterns and sedimentary facies of individual systems tracts within the lacustrine sequences display the same characteristics as marine depositional sequences the relatively low rate of thermal subsidence and the high rate of sediment supply resulted in a good sequence resolution within the third order sequences higher order sequences can be recognized with an average duration of about 0 1 0 5 ma

sulphide magma as a source of metals in arc related magmatic hydrothermal ore fluids as magma ascends in subduction zones decreasing pressure and temperature cause it to separate into two or more phases in a process known as exsolution hydrothermal ore fluids and metal rich sulphide melts may be products of this exsolution conventionally the ore fluids are thought to acquire their metal content directly from the parent magma however it is probable that the ore fluids and sulphide melts interact after exsolution and therefore possible that the sulphide melts are an important source of metals for the ore fluids here we use petrographic analyses of erupted sulphide melts and compositional analyses of volcanic gases emitted immediately after an eruption at merapi volcano indonesia to show that magmatic hydrothermal fluids can derive their metals from dissolution of sulphide melts we find that the volcanic gases exhibit metal ratios that are comparable to those in the erupted sulphide melts furthermore we show that gases sampled immediately after the eruption have metal concentrations that are orders of magnitude higher than those of gases emitted during periods of quiescence we propose that the metal content of ores forming in volcanic arc environments is established by exsolution accompanying injections of primitive magma immediately before explosive eruptions the metal content of ore deposits formed during subduction zone volcanism was thought to be established when the ore fluid separates from the parent magma analyses of metal concentrations in erupted melts and the volcanic gases emitted after an eruption in indonesia reveal that metals can be added to the ore fluid later during mixing with separated melts

the structure of the lowermost mantle determined by short period p wave amplitudes summary the seismic velocities in the d region lowermost 200 km of the mantle are recognized to be anomalously low though the details of the velocity structure are not known the structure of d is important in particular whether a smooth velocity model is appropriate or not a smooth decrease in the seismic velocities would be consistent with a thermal boundary layer at the base of the mantle we have used the amplitudes of short period t 1s p and diffracted p waves to investigate the internal structure of d a short period amplitude data set is obtained by using underground nuclear events as sources and applying receiver corrections to the amplitudes receiver effects are largely responsible for the factor of 8 scatter in the amplitudes of the north american wwssn stations applying receiver corrections reduces the scatter to a factor of 2 thereby providing a quantitatively useful amplitude profile into the core shadow using soviet events and north american wwssn stations the d layer beneath the north polar region is well sampled the core shadow at t 1 s begins sharply at a distance of 95 5 and the slope of the amplitude decay is well defined also the amplitudes decrease slightly from 87 to 90 then increase to 95 synthetic seismograms are used to test various earth models with the important conclusion that the amplitudes from smooth d models with a small velocity gradient in d decay too slowly in the shadow this mismatch cannot be satisfactorily explained by random forward scattering or a thin low q layer within d anelastic calculations show that a thin low q layer in d decreases the amplitudes before the shadow with little effect on the decay slope in the shadow all of the features of the observed amplitude profile can be explained as the interference effects of a model that has a low velocity zone in the upper part of d followed by a normal velocity gradient in the lower part of d this type of model polar series also explains the scatter often observed in dt d beyond 90 the interference effects and required velocity changes in d are small and long period amplitudes will respond only to the averaged velocity gradient in d the polar models imply a compositional and or phase change at the top of d thus the preferred seismological model does not allow the d region to be interpreted as a single thermal boundary layer between the mantle and core

inhomogeneities near the core mantle boundary evidenced from scattered waves a review statistical properties of small scale inhomogeneities wavelengths between 20 and 70 km near the core mantle boundary are inferred from scattered core waves observations of scattered core waves at large seismic arrays and worldwide networks indicate that the inhomogeneities have a global nature with similar characteristics however there may exist a few regions having markedly stronger or weaker strengths scattering by volumetric inhomogeneities of about 1 inp wave velocity in the lower mantle or by about 300 m of topographic relief of the core mantle boundary can explain the observations at present it is not possible to rule out either of these two alternatives or a combination of both

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

global mantle shear velocity model developed using nonlinear asymptotic coupling theory we present a three dimensional shear velocity model of the whole mantle developed using s h waveform data the model is expressed horizontally in terms of spherical harmonics up to degree 12 and vertically in terms of legendre polynomials up to degrees 5 and 7 in the upper and lower mantle respectively what distinguishes this model from other tomographic models published to date is 1 the theoretical normal mode based wave propagation approach where we include across branch mode coupling terms in order to model the body wave sensitivity to structure along the path more accurately 2 the wave packet weighting scheme which allows to balance contributions from high amplitude and low amplitude phases increasing the resolution in some parts of the mantle we also relax the constraints on the moho depth which is allowed to vary in the inversion thus absorbing some uncertainties in crustal structure the resulting model is generally in good agreement with other recent global mantle s velocity models and with some regional models the rms profile with depth has more power than other models in the upper mantle lower mantle transition region and the zone of increased power and low degree structure near the base of the mantle is confined to the last 500 km in depth this model provides a particularly good fit to the non hydrostatic geoid through harmonic degree 12 79 variance reduction as well as good fits to observed splitting functions of s velocity sensitive mantle modes indicating that both large scale and small scale features are really well constrained

origin and fate of sulfide liquids in hotspot volcanism la reunion pb isotope constraints from residual fe cu oxides immiscible sulfide liquids in basaltic magmas play an important role in trace metal transport and the sulfur budget of volcanic eruptions however sulfides are transient phases whose origin and fate are poorly constrained we address these issues by analyzing sulfide destabilization products preserved in lavas from la reunion island iron oxide globules and coatings typically 20 80 m in size were found to occur in vesicles of differentiated lavas from piton des neiges and recent pumice samples from piton de la fournaise field and mineralogical evidence indicates that the iron oxides are syn eruptive phases not resulting from hydrothermal processes samples were first studied by scanning electron microscopy the globules were separated whereas the smaller spherules and coatings were concentrated by magnetic sorting and acid leaching and samples were processed through wet chemistry the fe oxide phases comprise 49 74 wt fe 26 40 wt o and up to 6 wt cu 811 ppm ni 140 ppm bi and 8 5 ppm pb compared to the host lava cu ni and bi are enriched by a factor of 101 103 systematic pb isotope disequilibrium between 500 ppm and 2 9 for 206pb 204pb exists between fe oxides and host rocks with fe oxides generally displaying less radiogenic ratios unradiogenic pb is a typical signature of sulfide which tends to concentrate pb but not its parent elements u and th thus both the chemical and isotopic compositions of the vesicle hosted fe oxides suggest that they are more or less direct products of the destabilization of immiscible sulfide liquids although pb dominantly partitions into the gas phase during sulfide breakdown the original pb isotope signature of sulfide is preserved in the residual oxide the composition estimated for the parent sulfides 206pb 204pb 18 20 18 77 207pb 204pb 15 575 and 208pb 204pb 38 2 38 8 precludes a genetic link with the la reunion plume and suggests a lithospheric or crustal origin it is estimated that magma ascent velocities at piton de la fournaise are high enough to counterbalance the settling velocities of millimeter size sulfides despite their high density sulfide liquids are thus transferred upward during eruptions and their destabilization contributes to so2 emanations assimilation of foreign sulfides from the lithosphere can explain why so2 emissions sometimes e g during the april 2007 eruption exceed those predicted from the s content of melt inclusions