propagation characteristics of lg across the tibetan plateau abstract we present the results of a study on the propagation of lg within the tibetan plateau we analyze over 1200 seismograms for lg propagation from 185 local and regional earthquakes recorded at distances from 150 to 2000 km 52 of which are located within the tibetan plateau although the propagation of lg has been observed across most of asia lg has not been observed for paths crossing the tibetan plateau we analyze paths that cross the plateau boundaries and paths contained entirely within the tibetan plateau lg is generated within the tibetan plateau and can propagate to epicentral distances of at least 600 km for events located outside of the tibetan plateau lg is either absent or severely diminished for paths that cross both the himalayan and kunlun ranges confirming that the margins of the plateau weaken lg transmission based on the observations from our qualitative analysis we invert lg amplitudes for event station paths that are confined to the tibetan plateau to estimate the quality factor q the inversion yields a frequency dependent q function q f 366 37 f 0 45 0 06 0 5 f 16 h z similar observations in other areas indicate that frequency dependent apparent q within the tibetan plateau is well below that expected for a typical continental interior instead it has a frequency dependence that is characteristic of a tectonically active region

the iberian type of volcano sedimentary massive sulphide deposits the iberian pyrite belt located in the sw iberian peninsula contains many paleozoic giant and supergiant massive sulphide deposits including the largest individual massive sulphide bodies on earth total ore reserves exceed 1500 mt distributed in eight supergiant deposits 100 mt and a number of other smaller deposits commonly with associated stockwork mineralizations and footwall alteration haloes massive sulphide bodies largely consist of pyrite with subordinated sphalerite galena and chalcopyrite and many other minor phases although substantial differences occur between individual deposits both in mineral abundance and spatial distribution these deposits are considered to be volcanogenic roughly similar to volcanic hosted massive sulphides vhms however our major conclusion is that the iberian type of massive sulphides must be considered as a vhms sub type transitional to shms

mineralogy and chemistry of massive sulfide deposits from the juan de fuca ridge six hydrothermal vent sites and associated benthic communities were located in the axial valley of the southern juan de fuca ridge using transponder navigated bottom photography the hydrothermal deposits form ledges and shallow mounds within a central zone characterized by a linear bathymetric depression and numerous collapse features the flat valley floor adjacent to the central zone consists of ferrobasalt lobate flows and sheet flows sediment cover is minimal vent sites are characterized by concentrations of tube worms clams benthic siphonophores and several unidentified fauna two types of massive sulfide were dredged from one of the vent sites type a samples are angular slabs of dark gray zn rich sulfide with interlayers and a thin partly oxidized crust of fe sulfide these layered sulfide aggregates appear to be fragments of a sulfide wall enclosing an active hydrothermal vent the outer sulfide wall is composed mainly of colloform fe sulfide and fe poor sphalerite deposited under lower temperature conditions whereby sea water and hydrothermal fluid mix above the discharge point with continued sulfide deposition the wall inhibits mixing of sea water and hydrothermal fluid inside the wall the intensifying hydrothermal system deposits a higher temperature assemblage of granular fe rich sphalerite wurtzite pyrite and minor cu fe sulfide the zonation in wurtzite from fe rich cores to fe poor rims may result from a late stage cooling of the hydrothermal fluid and or a change in fluid chemistry the sulfide wall grows outward where a rupture in it permits the escape of high temperature fluid and then deposition of a secondary shell over the breakthrough point as temperature increases earlier formed minerals dissolve and zn fe and pb migrate toward the outer sulfide wall tube worms flourished in the outer wall of type a samples and abandoned tube structures served as conduits for the late stage hydrothermal fluids type b sulfide samples are subrounded spongy textured fragments composed almost entirely of dendritic aggregates of pale fe poor colloform sphalerite and opaline silica this type of sulfide is deposited in open space by moderate to low temperature fluid discharging at a slow but variable rate the fluid becomes increasingly oxidizing resulting in late stage deposition of hematite barite and sulfur type b samples show little evidence of burrowing animals this type of sulfide may be deposited in settings peripheral to sites of focused discharge

a study of the regional variation of low frequency around the korean peninsula we studied regional graphic 1 at 1 hz graphic 2 around the korean peninsula based on broadband vertical component seismic records of six incorporated research institutions for seismology iris global seismographic network stations and 19 korean stations of the korea institute of geoscience and mineral resources kigam using 177 seismic events with magnitudes between 5 3 and 5 7 and depths less than 50 km the reversed two station method was applied and 94 high quality interstation paths were selected from 869 possible pairs these results show high graphic 3 paths around the sea of japan east sea reflecting the typical oceanic structure and low graphic 4 paths around northeastern china related to inactive seismicity assigning these path values into 193 cells around south korea with a size of 1 by 1 we observed that the regional graphic 5 decreased gradually from east to west between 2 and 1 10 3 1 embed inline graphic 2 gif 2 embed inline graphic 3 gif 3 embed inline graphic 4 gif 4 embed inline graphic 5 gif 5 embed inline graphic 6 gif

evaluating large eddy simulations using volume imaging lidar data the authors apply data analysis techniques that demonstrate the power of using volume imaging lidar observations to evaluate several aspects of large eddy simulations less they present observations and simulations of an intense and spatially evolving convective boundary layer on 13 january 1998 during the lakeinduced convection experiment lake ice to enable comparison of observed and simulated eddy structure aerosol scattering was estimated from les output of relative humidity a passive tracer and liquid water spatial and temporal correlation functions of aerosol structure from horizontal planes reveal the mean and turbulent convective structure the correlation functions of the observed and simulated aerosol backscatter are presented as a function of altitude and offshore distance best fit ellipses to the closed contours encircling the origin of the correlation functions are used to obtain the mean ellipticity and orientation of the structures the authors demonstrate that these two parameters are not sensitive to minor changes in the functional relationship between humidity and optical scattering the lidar derived mean wind field is used as a reference for evaluating the les mean flow the ellipses from lidar data indicate that structures near the surface tend to be aligned with the mean wind direction while in the entrainment zone they are aligned perpendicular to the mean wind direction in the middle of the mixed layer convective plumes tended to be circular and therefore had no preferred orientation at small lags at longer lags however the correlation functions from the middle of the mixed layer show that the observed convective plumes were organized into linear bands oriented perpendicular to the mean wind direction the perpendicular bands suggest the important role of gravity waves in organizing convective structures the study shows that the model generates reasonable coherent structures open cells where the les technique is expected to perform poorly near the surface and fails to capture the wind perpendicular organization of closed cells in the middle of the mixed layer where the les technique is expected to be robust the authors attribute this failure to the boundary conditions that limited the growth of waves above the mixed layer

an inversion of lg wave attenuation and site response in the north china region a joint inversion method for determining the lg wave attenuation along the propagation path and site response based on seismic spectral ratios was developed and applied to invert the lg wave attenuation and site response in the north china region is related to the quality factor q by f uq where u is the velocity waveform data of 200 earthquakes during 2006 2008 with m l 1 7 5 5 in the area of 38 41 n 114 120 e were selected for this study more than 1500 three component records chosen from 81 stations on the basis of the signal to noise ratio were used in the inversion the waveform data were processed in the frequency range of 1 6 hz with an interval of 0 2 hz the results indicate that there is remarkable heterogeneity in lg wave attenuation in the study area we divided the area into four regions according to the lg wave propagation paths lower values are found in the tectonic mountain region higher values occur in the tectonic basin region and moderate values are found for the propagation paths passing through both the mountain and basin regions on the vertical component was found to be frequency dependent and in the form graphic 1 and graphic 2 for propagation paths in the mountain and basin regions respectively and graphic 3 and graphic 4 for paths passing through both mountain and basin regions with seismic ray direction from the mountain to the basin and vise versa respectively the absolute quality factor q ranges from 125 to 306 the response of rock sites is smooth and flat and less than five at low frequency while that for soil sites is higher than for rock sites for soil sites the amplification of low frequency waves is higher than that for high frequency waves for both site response and attenuation no significant differences were observed between different components online material source parameters of the studied earthquakes 1 embed inline graphic 1 gif 2 embed inline graphic 2 gif 3 embed inline graphic 3 gif 4 embed inline graphic 4 gif

spatial distribution of coda q in south korea analyzing spectral attenuation of coda waves we first mapped coda q values in the crust over the whole of south korea during the period from 1995 to 2004 we selected 574 north south component seismograms with epicentral distances less than 100 km from 328 earthquakes with magnitudes between 1 4 and 5 2 we estimated coda q values using the single isotropic scattering model at center fre quencies of 1 5 3 6 9 12 15 and 18 hz and found significant spatial variation over all frequency ranges and strong frequency dependence of coda q in the region the estimated coda q value at 1 hz q0 and the g value ranges are 80 300 and 0 4 1 1 respectively the values have strong correlation with the regional geology in the korean peninsula low q0 values are mainly obtained in the regions com prising sedimentary strata in southeastern south korea whereas granite regions in the northern part of south korea show high q 0 the q 0 values in the study area agree well with those of the eastern china and kyushu western japan furthermore our g values are also in good agreement with those of japan online material locations of seismometers list of event station pairs and linear regression of qc measurements

grass cover density and metal speciation in profiles of a tailings pile from a mining zones in zacatecas north central mexico the 7 year old mine tailings pile p2 from concepcion del oro has been revegetated spontaneously by xerophyte grasses covering about the 30 of its surface to elucidate the effect of the grass cover in the geochemical behavior of the sulfide minerals sm and metals the strata of four selected profiles p2 i p2 ii p2 iii and p2 iv with high middle low and null grass cover respectively were analyzed mineralogically and chemically using scanner electron microscopy x ray diffractometer and performing a six step sequential extraction method an older 50 year old and uncovered without grass cover profile of the tailings pile p3 was also analyzed in all the profiles from p2 the sm oxidation is not yet an extended process however the samples from the uncovered profile p2 iv showed evidences of sm pyrite and chalcocite oxidation as well as the presence of gypsum and fe oxides as the major secondary phases resulted from the sm oxidation additionally the carbonate content and ph values in p2 iv were lower than in the covered profiles from p2 the oldest and uncovered p3 i profile showed an extensive oxidation of sulfurs which resulted in the depletion of carbonates and a ph 2 another distinctive characteristics of the covered profiles was that pb cu and zn were mainly associated with the reducible fractions carbonates and or amorphous oxides meanwhile in the uncovered p2 iv and p3 i such metals were mainly associated with the oxidizable fraction crystalline oxides the results suggest that the mineralogical transformations control metal stability in plant covered impoundments phytostabilization the occurrence of a thick grass cover with an efficient water usage and retention seems to shun both the acidic dissolution of carbonates and the reductive dissociation of the formerly present oxyhydroxides which is desired for remediation tasks this is the first report about the effects of grass cover for a carbonaceous and unsaturated mine tailings from a semiarid region that can help in a better understanding of the scope of phytoremediation in such conditions

lg attenuation near the north korean border with china part i model development from regional earthquake sources we have collected broadband data from three seismic networks two portable and one permanent in a remote part of northeast china bordering north korea the combined network coverage allows first hand investigations of seismic wave propagation in a region of import for nuclear test ban monitoring research application of the reversed two station method to the newly acquired data has pro duced stable measurements of the quality factor q q0f for lg waves the re sults a weighted regional average over 23 interstation paths involving 51 events and 21 stations point to 1 hz q or q0 of 345 and of 0 38 in a jarring incongruity with what appears to be a popular perception of the region as being of very low attenuation for lg waves the results also show that lg q varies from one interstation path to another the highest lg wave attenuation 110 q 0 140 is found along intersta tion paths that crossed two recently active volcanoes huangyishan and chang baishan the subregion exhibiting the next highest lg attenuation is bohai an extensional basin known to feature above average heat flow

a new sulphur isotopic study of some iberian pyrite belt deposits evidence of a textural control on sulphur isotope composition the sulphide deposits of the iberian pyrite belt ipb represent an ore province of global importance our study presents 113 new sulphur isotope analyses from deposits selected to represent the textural spectrum of ores measured 34s values range from 26 to 10 mostly for massive and stockwork ores in agreement with data previously published in situ laser 34s analyses reveals a close correlation of 34s with texture primary diagenetic textures are dominated by relatively low 34s 8 to 2 whereas stockwork feeder textures are dominated by higher 34s 3 to 5 intermediate textures mainly coarse textures in stratiform zones have intermediate 34s although they are mostly dominated by the high 34s component rare barite has a homogeneous 34s around 18 which is consistent with direct derivation from lower carboniferous seawater sulphate a dual source of sulphide sulphur in the ipb deposits has been considered a hydrothermal source derived from reduction of coeval seawater sulphate in the convective systems is represented by sulphide in the feeder zones here variations in 34s are caused by variations in the extent of the sulphate reduction which governs the so4 h2s ratio the second end member was derived from the bacterial reduction of coeval seawater sulphate at or near the surface as reflected in the primary textures a distinct geographical variation in 34s and texture from sw more bacteriogenic and primary textures to ne more hydrothermal textures and 34s which reflects a variation in the relative input of each source was likely controlled by local geological environments given that the sulphur isotope characteristics of the ipb deposits are unlike most vms and kuroko deposits and noting the dominance of a mixed reduced sedimentary and volcanic environment we suggest that the ipb could represent an ore style which is intermediate between volcanic and sedimentary hosted massive sulphide types

trondhjemites tonalites and diorites in the south portuguese zone and their relations to the vulcanites and mineral deposits of the iberian pyrite belt in the south portuguese zone close associations of diorites tonalites and trondhjemites occur north of the pyrite belt the period of their emplacement is pre carboniferous and not as has generally been assumed variscanpostorogen the trondhjemitic intrusive suite and the lower carboniferous spilite keratophyre association are related through their comagmatic derivation both series share sodium dominance low concentrations of large ion lithophile elements indicators of a water rich original magma and a deficient scorification of the element potential which was acummulated in the sulphide and manganese deposits of the pyrite belt through post volcanic hydrothermal processes the mineralogically and geochemically primitive composition of both plutomtes and vulcanites their mode of eruption from acid to basic facies as well as their position in the orogenic process indicate that they represent products of a successively proceeding partial melting of subducting oceanic crust the trondhjemitic intrusives are the initialites in the magmatic orogenic development

the geochemistry of hydrothermal alteration at the salgadinho copper deposit portugal the recently discovered salgadinho copper deposit 7 km nne of s luis portugal is located in the southernmost linear belt of outcropping low metamorphic grade deformed palaeozoic rocks famennian in the sw part of the iberian pyrite belt the stratabound replacement pyrite chalcopyrite mineralisation is present in variably altered felsic pyroclastic rocks which are overlain by pyritic graphitic shales and tuffs which have undergone alteration in the lowermost 5m the altered pyroclastic rocks are characterised by pale green celadonitic fluoro muscovite and in the most intense zone of alteration quartz ankerite and ore minerals are present pyrite chalcopyrite sphalerite tetrahedrite galena bournonite no exhalative cu zn or zn pb ore has been discovered associated with the submarine volcanic stratabound cu rich alteration zone alteration of feldspars and groundmass has involved a net loss from the system and gains in fe2 f h2o mg fe3 ca mn p ti s cu zn pb as sb ag and au at the expense of si k al and na the great enrichment of f in the altered rocks the association of zonal alteration facies with coarse grained pyroclastic masses and the intimate association of pale green celadonitic fluoro muscovite with mineralisation at salgadinho and most other deposits of the iberian pyrite belt represents a powerful exploration guide for submarine exhalative ores

amplitudes of regional seismic phases in relation to crustal structure of the sierra nevada california we have recorded and modeled th amplitudes of regional seismic waves produced by the nevada test site non proliferation experiment explosion along a 400 km profile across the southern sierra nevada of california along j this profile the amplitudes of the crustal phases pg and lg decrease monotonically with distance because of the cumulative effects of geometrical spreading and a t frequency dependent crustal attenuation given by q 138fo 76 1 f 8 hz this observation implies that the crust of the sierras is not more attenuative to p and s waves than the crusts of the adjacent great valley and basin and range the only amplitude anomaly related to the crustal structure is a strong attenuation of lg on the vertical component in the great valley due to the refraction of rays in the low velocity sediments of the basin ln contrast to pg and lg pn amplitude increases across the sierra nevada and the eastern edge of the great valley then some 30 km west of the exposed sierran batholith the amplitude of pn suddenly decreases by a factor of 10 on the basis of a new refraction model produced by the southern sierra nevada continental dynamics study and on numerical simulations of the pn pg energy ratio these changes in pn amplitude are shawn to be due to a local increase in crustal thickness from roughly 35 to 45 km centered under the western sierra the size and location of the amplitude anomaly can be explained with a gently sloping two layer crust mantle model with p velocities of 6 0 km s and 8 0 km s the small offset crustal root focuses pn waves toward the westernmost sierra nevada and the easternmost great valley significantly increasing the pn energy in these regions the focusing effects diminish rapidly toward the west as the moho is again horizontal

attenuation of multiphase surface waves in the basin and range province part i lg and lg coda summary broad band data recorded by the lawrence livermore laboratory network are used to investigate whether or not lg q and lg coda q have similar values in the basin and range province of north america in order to retrieve spectral estimates of the broad band lg and lg coda signals a hybrid method is used which retains high fidelity at lower frequencies while strongly smoothing the spectral estimates and minimizing the number of spectral points at high frequencies a stochastic approach is used to model the lg signal and ambient noise and to analyse results from two station determinations of lg q in the basin and range the effects of ambient noise frequency dependent station site response and focusing defocusing on lg q inversion are analysed it is shown that after averaging spectral ratios determined from repeated observations over four two station paths a modest site effect will not cause significant errors in the resulting lg q relation using this inversion scheme and spectral ratio estimates averaged over those paths at frequencies between 0 2 and 2 5 hz we obtain the relation qlg f 267 f 56 f0 37 0 06 for the basin and range province further constraints on lg q were obtained from lg coda which due to the natural averaging effect of scattering is insensitive to effects of focusing defocusing to investigate the validity of the single isotropic scattering model for lg coda in the basin and range province we calculated ischrons for scatterers corresponding to later lg coda signals as required by the single scattering model it is found that when significant portions of these isochrons are oceanic lg coda amplitude decay becomes irregular and abnormally slow suggesting a strong scattering reflection effect caused by the rapidly changing crustal structure along the coast applying the single isotropic scattering model to lg coda records with isochrons mostly confined to the continental crust results in q f 275 f 26 f 0 36 0 03 which is nearly identical to our qlg relation this indicates that even in a complicated geological province a joint interpretation of the dynamic properties of lg and lg coda can be successful and fruitful inconsistent lg q and coda q relations found in earlier studies in the basin and range province may be attributed to different settings of parameter trade offs different seismic phases or different dynamic properties being used

geology and geophysics as successful tools in the discovery of the lagoa salgada orebody sado tertiary basin iberian pyrite belt grândola portugal gravimetry was the main exploration method used in this high risk area to the north of the gr ndola fault in the iberian pyrite belt ipb it showed several targets among which the valverde lagoa salgada area stood out here in august 1992 a polymetallic massive sulphide orebody was found named lagoa salgada according to the geological characteristics of the area and to the nature of the surveyed targets other exploration techniques were used namely geology magnetometry resistivity electrical sounding magneto telluric seismic and mechanical drilling the deposit was found under a tertiary cover 128 m in depth complete with a 15 m thick gossan caused by paleoalteration with a supergene enrichment zone this gossan gave way to massive sulphides with intersections at times exceeding 60 m they are limited towards the footwall by an important fault with strong associated kaolinization which is interpreted as a reverse fault placed on the inverse limb of an anticlinal structure throughout the deposit the chemical composition of the mineralization showed great variation reaching significant values of zn pb sn cu as hg sb cd au and ag in the initial phase the deposit has an estimated tonnage of 5 mt it is related to a large gravity anomaly with the general orientation nw se which was investigated by 15 boreholes made by the instituto geologico e mineiro the drilling cut an important volcanic centre of an acid to intermediate nature around which intense hydrothermal activity was associated with contemporaneous sulphide mineralization the gravity anomaly has two nuclei a nw and a central one about 450 m apart where a pyrite orebody with polymetallic sulphides and stockwork sulphide mineralization are developed this discovery led to an extensive exploration project that confirmed the mining potentialities of the nw sector of the ipb to the north of gr ndola fault where previously no polymetallic sulphide occurrences were known

hydrochemistry mineralogy and chemical fractionation of mine and processing wastes associated with porphyry copper mines a case study from the sarcheshmeh mine se iran abstract the sarcheshmeh is one of the largest oligo miocene porphyry cu deposits in the world comparative hydrochemical mineralogical and chemical fractionation associated with mining efflorescence salts and processing wastes of this mine are discussed hydrochemical results showed that rock waste dumps reject wastes and old impoundments of tailings are the main sources of acid mine drainage waters amd that contain potentially toxic metals such as cd co cu mn ni and zn as well as al episodic fluxes of highly contaminated acidic waters were produced in a tailings dam over a short period of time secondary soluble minerals provide important controls on the quality of amd produced especially in old dry tailings impoundments secondary sulfate minerals such as gypsum magnesiocopiapite hydronium jarosite kornelite and coquimbite were found in rock waste drainages and in old weathered reject wastes highly soluble secondary minerals such as gypsum eriochalcite and bonattite are also observed in an evaporative layer on old tailings impoundments chemical fractionation patterns of potentially toxic elements showed that the geochemical behavior of metals is primarily controlled by the mineralogical composition of waste samples elements such as co cr cu mn ni and zn are readily released into the water soluble fraction from efflorescence salts associated with rock waste drainages as well as from the evaporative layer of old tailings potentially toxic elements such as as mo and pb are principally adsorbed or co precipitated with amorphous and crystalline fe oxides but they may also be associated with oxidizing primary sulfides and residual fractions following the development of the dammed tailings pond the secondary minerals were dissolved producing acidic waters contaminated by al 154 mg l 1 cu 150 mg l 1 cd 0 31 m gl 1 co 2 13 mg l 1 mn 73 7 mg l 1 ni 1 74 mg l 1 zn 20 3 mg l 1 and cl 1690 mg l 1 therefore the potential use of recycled water from the sarcheshmenh dammed tailings pond is diminished by the presence of corrosive ions like cl in highly acidic fluids that promote corrosion of pipes and pumps in the water recycling system

geochemical and geologic study of the volcano sedimentary sulfide orebody of la zarza province of huelva spain the la zarza orebody containing some 100 000 000 metric tons of ore is one of the three most important ones in the huelva province spain it overlies the second phase of acid volcanic activity within a volcanic sedimentary succession of visean age the stratigraphically lower part of the orebody consists of a finely bedded polymetallic ore overlain by a massive pyrite facies 90 of the orebody which is in turn covered by a more or less discontinuous resedimented pyritic capping the distribution of the metals within the orebody differs from the classical pattern in la zarza the pb zn contents are greater in the lower parts of the deposit than in the upper parts while cu is more or less independent of other metals and shows a typical basal concentration in a breccia type ore and stockwork restricted to a small area the foot and hanging walls are made up of acid epiclastic rocks and pelites and are practically without lavas however it is possible to recognize volcanic eruption centers some kilometers to the east of the mine below the sulfide orebody an intensively chloritized zone some hundred meters in diameter most probably represents a hydrothermally altered pipe overall the wall rocks are characterized by their enrichment in mg and impoverishment in na and si within the chloritized pipe an overall lowering of alkali values is accompanied by a strong increase in mg as analyzed by spectrometry and atomic absorption the distribution of trace elements in wall rocks and ore cu pb zn v co cr and mn tends to show the lack of consanguinity between ore and wall rocks on the one hand and the reasonably clear association between the ore and a late volcanic hydrothermalism on the other furthermore the high co ni ratios correspond to a hot sulfide deposition there is no distinct dispersion halo except for the presence of some disseminated sulfides around and very close to the ore the distribution of the elements and their correlations differ betweeen the ore and wall rocks although it lies on a volcanic sedimentary footwall the la zarza orebody is thus rooted in a hydrothermally altered pipe nevertheless the migration of magnesium and other metals is unconnected and there is evidence of a certain independence among the different metals above all in the case of copper

regional seismic observations of the 9 october 2006 underground nuclear explosion in north korea and the influence of crustal structure on regional phases 1 the crustally guided shear wave lg is typically the most prominent phase of a nuclear explosion at regional distance this lg phase is analyzed often to discriminate a nuclear explosion from a natural earthquake in addition the lg phase allows us to determine the size of the detonation a nuclear explosion test in north korea was conducted on 9 october 2006 the epicenter was located close to the eastern shore of the korean peninsula resulting in raypaths that vary significantly according to the azimuths in particular rays radiated in the southern direction experience lateral variation of crustal structures at the continental margin we examine the influence of raypaths on regional seismic phases by comparing the spectra and waveforms from different raypaths three natural earthquakes in north korea are also examined to determine the raypath effect we find that the lg from the nuclear explosion dissipated significantly as result of energy leakage into the mantle resulting from variations in crustal thickness along the portion of the raypath traversing the western tip of the sea of japan east sea some of the leaked energy develops into mantle lid waves sn causing a large energy increase to sn a similar feature is observed in the records of natural earthquakes this feature is confirmed by seismic waveform modeling the raypath effect also causes underestimation of magnitude the lg body wave magnitude mb lg is estimated to be 3 8 4 2 for records from pure continental paths and 2 6 3 4 for records from paths crossing continental margins this result illustrates the need to consider raypath effects for the correct estimation of magnitudes of regional events including a nuclear explosion

an inversion of lg wave attenuation and site response from seismic spectral ratios in the eastern china region abstract both lg wave attenuation and site responses are determined in the eastern china region the region ranges from 26 n to 33 n and 117 e to 124 e we analyze over 1360 three component seismograms from 92 local and regional earthquakes the seismograms are recorded in the distance range of 100 600 km the earthquakes occurred between 2002 and 2012 in the region and varied in magnitude between 2 0 and 4 7 m l a combined inversion method which can simultaneously estimate attenuation and site response from seismic spectral ratios is implemented in the study modeling errors are determined using a delete j jackknife resampling technique fourier spectral amplitudes are measured from lg phases windowed between the group velocity limits 2 6 and 3 6 km s the inversion are performed in a frequency range of 1 6 hz with an interval of 0 2 hz the frequency dependent quality factor is modeled in the form of q q 0 f the eastern china region displays high q 0 and a weaker frequency dependence characterized by the functions q 335 16 f 0 45 0 02 q 411 21 f 0 26 0 01 and q 432 26 f 0 24 0 01 for vertical north south and east west components respectively the values are similar to the average for other stable regions of the globe site responses from 32 stations are estimated in the region most stations do not show obvious amplification the site responses are mainly smooth flat and less than 5 in the frequency range of 1 6 hz

comparison of rio tinto spain and guaymas basin gulf of california an explanation of a supergiant massive sulfide deposit in an ancient sill sediment complex the volcano sedimentary unit that hosts the stratiform massive sulfide mineralization at rio tinto is reinterpreted as a sill sediment complex that in many respects is analogous to the example that is currently forming in the guaymas basin gulf of california however rio tinto is distinctive because 1 it is a product of bimodal magmatism 2 it has a much higher sill sediment ratio 4 1 lessening the extent of ore forming metal depletion during interaction between hydrothermal fluid and wet sediment and 3 most of the sills were emplaced penecontemporaneously as shown by the ubiquitous development of peperitic sill margins despite the narrowness of the sedimentary screens these data together with evidence for local extrusive behavior imply rapid formation of the complex at exceptionally high levels of emplacement it follows that in the complex variations in thickness of 400 m were directly expressed as basin floor deformation and that troughs in the resultant topography were able to trap exhalative hydrothermal plumes thus preserving the sulfides from dispersion also crucial to the mineralization process was the sheetlike form of the sill complex which by acting as a cap prevented regular convective cell patterns from forming and focused considerable discharge at areas of weakness the intense magmatic pulse the creation of pronounced topography and the capping of the hydrothermal system combined to make a 500 mt supergiant deposit

bismuth and cobalt minerals as indicators of stringer zones to massive sulphide deposits iberian pyrite belt the stringer zones and commonly the interaction zone at the base of the massive sulphide mounds in the iberian pyrite belt contain bismuth and cobalt minerals that are not found in the overlying massive sulphides these are fairly rare cobalt sulphoarsenides cobaltite alloclasite galucodot that were formed at the beginning of the massive sulphide genesis and fairly common bismuth sulphides bismuthinite hammarite wittichenite cosalite kobellite joseite etc including species rare at world scale nuffieldite giessenite jaskolskiite that were deposited from last stage high temperature 300 c copper bearing fluids containing bi te se the last stage fluids precipitated chalcopyrite containing cu bi te se sulphosalts at the base of the sulphide mound to form a high cupriferous zone their interaction with the massive sulphides is reflected by the formation of an exchange zone a few metres thick showing chalcopyrite disease textures at the base of the mound this zone forms the upper limit of potentially economic copper enrichment and of bismuth minerals gold is undoubtedly in part if not totally related to this last phase the bismuth concentrations being equivalent in the massive sulphides and the stringers the presence of bismuth minerals in the stringer zones results from high temperature conditions combined with a rarity of galena which impedes absorption of available bi the distribution of these bismuth minerals provides a basic mineralogical zoning in the stringer zone with a deep low as2 zone containing native bismuth and tellurides and a shallow higher as2 zone in contact with the massive ore sensu stricto and containing complex bismuth sulphides these results make it possible to distinguish between sulphide veinlets belonging to stockwork zones of massive orebodies and veinlets of an ambiguous nature and provide mineralogical criteria for the proximity of copper rich zones they enrich the very complex mineralogy of the iberian pyrite belt

the 1984 southern yellow sea earthquake of eastern china source properties and seismotectonic implications for a stable continental area on 21 may 1984 a strong shock ms 6 3 mb 5 7 occurred in the southern yellow sea which shook the densely populated coastal area of eastern china about 1 min before the main shock a foreshock of mb 5 4 occurred because of interference from the foreshock no reliable p wave first motions or focal mechanisms have been obtained for the main shock from local seismic data in this paper long period teleseismic data have been used to investigate the source mechanism fault plane solutions determined from first motions as well as p and sh waveforms show a predominant strike slip motion with a small dip slip component on a steeply dipping plane the tectonic environment of this event supports the observation that margins of former rifts tend to be sites of midplate seismic source regions the yellow sea developed in a cratonic environment due to early cenozoic rifting the major graben faults strike nne ssw to ne sw and are intersected by second order faults trending wnw ese aftershock distribution suggests that the fault which generated the main shock probably strikes wnw ese the mechanism determined in this paper strikes 120 dips 88 and slips 28 this solution suggests that the earthquake ruptured along a secondary fault near the intersection of a more major nne ssw trending fault the epicentral area is subject to to an ene wsw compression and a nnw sse extension the seismic moment and focal depth are determined to be 1 09 1025 dyne cm and 12 4 km respectively relative hypocentral locations indicate that the focal depth of the foreshock is similar to that of the main shock and the hypocenter of the foreshock is located very close to the wnw ese striking nodal plane of the main shock mechanism and is about 20 km away from the main shock hypocenter source properties of the southern yellow sea earthquake have been compared with those of three major earthquakes of north china the stress drop of the yellow sea earthquake is determined to be about 42 bars this value is much lower than the stress drops computed for the 1966 hsingtai and the 1975 haicheng earthquakes of north china the southern yellow sea is characterized by short recurrence intervals while the hsingtai and haicheng areas have very long recurrence intervals the short recurrence intervals and low stress drop may reflect a lower material strength at the source region in the yellow sea

laboratory study of calcite gypsum sludge water interactions in a flooded tailings impoundment at the kristineberg zn cu mine northern sweden abstract due to liming of acid mine drainage a calcite gypsum sludge with high concentrations of zn 24 400 6900 g g 1 cu 2840 680 g g 1 and cd 59 20 g g 1 has formed in a flooded tailings impoundment at the kristineberg mine site the potential metal release from the sludge during resuspension events and in a long term perspective was investigated by performing a shake flask test and sequential extraction of the sludge the sequentially extracted carbonate and oxide fractions together contained 97 of the total amount of cd co cu ni pb and zn in the sludge the association of these metals with carbonates and oxides appears to result from sorption and or coprecipitation reactions at the surfaces of calcite and fe al and mn oxyhydroxides forming in the impoundment if stream water is diverted into the flooded impoundment dissolution of calcite gypsum and presumably also al oxyhydroxides can be expected during resuspension events in the shake flask test performed at a ph of 7 9 remobilisation of zn cu cd and co from the sludge resulted in dissolved concentrations of these metals that were significantly lower than those predicted to result from dissolution of the carbonate fraction of the sludge this may suggest that cationic zn cu cd and co remobilised from dissolving calcite gypsum and al oxyhydroxides were readsorbed onto fe oxyhydroxides remaining stable under oxic conditions in a long term perspective 102 a 97 of the cd co cu ni pb and zn content of the sludge potentially is available for release by dissolution of calcite and reductive dissolution of fe oxyhydroxides if the sludge is subject to a soil environment with lower dissolved ca concentrations ph and redox than in the impoundment

the internal structure of an active sea floor massive sulphide deposit the hydrothermal circulation of sea water through permeable ocean crust results in rock water interactions that lead to the formation of massive sulphide deposits these are the modern analogues of many ancient ophiolite hosted deposits1 4 such as those exposed in cyprus here we report results obtained from drilling a series of holes into an actively forming sulphide deposit on the mid atlantic ridge a complex assemblage of sulphide anhydrite silica breccias provides striking evidence that such hydrothermal mounds do not grow simply by the accumulation of sulphides on the sea floor indeed the deposit grows largely as an in situ breccia pile as successive episodes of hydrothermal activity each form new hydrothermal precipitates and cement earlier deposits during inactive periods the collapse of sulphide chimneys dissolution of anhydrite and disruption by faulting cause brecciation of the deposit the abundance of anhydrite beneath the present region of focused hydrothermal venting reflects the high temperatures 150 c currently maintained within the mound and implies substantial entrainment of cold sea water into the interior of the deposit these observations demonstrate the important role of anhydrite in the growth of massive sulphide deposits despite its absence in those preserved on land

strong lg wave attenuation in the northern and eastern tibetan plateau measured by a two station two event stacking method 1 the regional seismic phase lg which involves shear wave reverberations in the crust is strongly attenuated along propagation paths in northern and eastern tibet robust estimates of the attenuation quality factor qlg in these regions are obtained using a two station two event stacking method for broadband vertical component lg data in the passband 0 2 1 0 hz we find average 1 hz qlg values qo of 79 4 in northern central tibet and 119 17 in eastern tibet for the 0 2 0 5 hz passband localized regions of eastern tibet have qo estimates ranging from 66 to 121 these results confirm and augment the spatial coverage of recent estimates of low qo values in north central and south central tibet and support the notion of widespread partial melting of the crust throughout the plateau

les model sensitivities to domains grids and large eddy timescales abstract this study has addressed the sensitivity of large eddy simulation les models to domain size grid resolution and the number of large eddy turnover times t of integration and their respective effects on the characteristic turbulence statistics computed from the simulation of convective flows in planetary boundary layers pbls this includes the review of relevant results from past les studies as well as new findings using les models for type i cloud topped boundary layers with ice and snow horizontal domains in this study were varied from 5 km 5 km to 10 km 10 km grid length varied from 125 m 125 m to 78 m 78 m and three t times of 11 15 and 19 adequate results for horizontal variance were obtained for the 10 km 10 km domain the 78 m 78 m grid and all the t values based on the evaluation criteria introduced to replace the time averaging methodology similar results were found for vertical velocity skewness however 19t offered improvement over 11t and 15t showi

magnitude estimation and source discrimination a close look at the 2006 and 2009 north korean underground nuclear explosions north korea detonated its first known nuclear device a moderate sized event in the northeastern corner of the korean peninsula on 9 october 2006 a second one several times more powerful was set off nearby on 25 may 2009 both were recorded at high signal to noise ratio snr by a modern broadband 0 03 30 hz network of seismographs deployed since 2004 along the sino korean border and by station mdj due north of ground zero spanning a wide range of station azimuth 259 11 the near regional 1 3 3 3 paths are all purely continental and away from continental margins making the resulting data uniquely suited for assessing the capabilities of an out country network to verify the compliance by north korea with a future comprehensive nuclear test ban treaty the mblg magnitudes for the 2006 and 2009 nuclear explosions were determined anew giving 4 32 0 13 and 4 86 0 13 respectively we show that the ms mblgmethod correctly differenti ates these nuclear explosions from natural earthquakes although the differentiation was not achieved in studies based on published mblg values an analysis of the pg lg ratio derived from recordings of the two nuclear tests and of four regional earthquakes selected for their comparable magnitudes 4 2 mb 4 8 reveals that the ratios associated with the explosion and earthquake populations showed surpris ingly little overlap for a broad frequency range of 3 to 11 hz in principle ms mb can also be used to correctly identify the nuclear tests as explosions but the mb measure ment for such moderate sized events is not as robust as the mblg measurement rendering this traditionally favored method less practical

a novel technique for measuring lg attenuation results from eastern canada between 1 to 10 hz spectral amplitudes of regionally recorded lg waves are studied in detail between 0 6 and 10 hz using vertical component velocity seismograms of the eastern canada telemetered network stations and a supplementary seismic research observatory type station at glen almond gac quebec we find that the site responses vary among these stations by more than a factor of 3 within the frequency range of interest furthermore they are found to be strongly frequency dependent consequently it is essential that they be taken into consideration in studies of lg wave attenuation and lg source spectra of regionally recorded seismic events we present a new method of measuring interstation surface wave attenuation which is closely related to the conventional two station method while retaining all the desirable features of the conventional two station method the new technique which we will call the reversed two station method allows simple direct one parameter determination of the lg wave attenuation from sparse spectral data in a manner unaffected by station site effects and associated instrument error the reversed two station method is successfully tested over weakly attenuating short 53 to 210 km interstation paths in eastern canada a difficult experimental condition by normal standards the lg attenuation coefficient 0 6 to 10 hz in eastern canada is found to be frequency dependent and of the form f 0 0008 f 0 81 km 1 at higher frequencies the lg attenuation appears to be essentially frequency independent this latter finding is preliminarily interpreted as evidence that regionally recorded lg waves in the canadian shield are as in the case of lg waves propagating through the structurally complex appalachian province contaminated by the high frequency coda of sn waves the lg contamination over the shield paths becomes severe starting at 14 hz twice the frequency above which the lg signal propagating over the appalachian province becomes completely dominated by non lg arrivals

remobilisation of base metals and gold by variscan metamorphic fluids in the south iberian pyrite belt evidence from the tharsis vms deposit the tharsis massive sulphide deposit one of the major vms type deposits in the iberian pyrite belt ipb was severely deformed by the variscan tectono thermal events the question of whether or not these events affected the metal distribution in the deposit has been addressed by simultaneously studying the mineral parageneses tharsis stockwork and the fluid circulation at local and regional scales the results are 1 the early paragenesis in the stockwork q1 quartz pyrite chlorite phengitefcobaltitefankerite was strongly overprinted by a late post kinematic mineral deposition including new quartz veins q3 quartz and base metal sulphides chalcopyrite sphalerite bi and te minerals pyrite and galena and gold 2 at a regional scale fluids accompanying the peak metamorphism conditions ca 300 mpa ca 300 jc were of c o h n nacl type co2 dominated with ch4 and n2 and are considered to be metamorphic on the basis of microthermometry and geochemistry the late to post kinematic evolution retrograde stage was characterised by a pressure drop down to 40 mpa lithostatic to hydrostatic transition and a heat input leading to temperatures z430 jc then decreasing to temperature around 170 jc fluids of the retrograde type exhibit both dilution of the c o h n nacl fluid by a low salinity meteoric water and progressive loss of volatile components 3 fluids of the retrograde type pervasively percolated through the tharsis stockwork and were responsible for the strong mineral overprint on the early deformed paragenesis all the measurable fluid inclusions f i record these late fluids there are primary fluid inclusions in q1 but they are systematically imploded due to the external overpressure generated by the variscan tectonic events although base metal distribution in the stockwork is basically the result of the

dynamics of contaminants in phosphogypsum of the fertilizer industry of huelva sw spain from phosphate rock ore to the environment abstract the dynamics of trace elements from phosphate rock ore to the environment in a phosphoric acid plant located in sw spain and the impact of phosphogypsum wastes were investigated through total digestion and bcr sequential extraction based on total concentration element transfer factors as criteria for examining the potential environmental risk of waste with respect to ore rock were calculated and it was observed that most trace elements are only transferred into phosphogypsum at rates of 2 12 however based on those concentrations that are likely to be most readily mobile in the environment phosphogypsum acts as a higher emission source of contaminants than the original rock about 100 million tonnes of phosphogypsum are stack piled in a dump of 1200 ha over salt marshes of an estuary formed by the confluence of the tinto and odiel rivers phosphogypsum has been applied at the recommended rate of 20 25 t ha since 1978 2001 to improve fertility and reduce na saturation in agricultural soils of the guadalquivir river valley 140 km 2 phosphogypsum capacity as a source of mobile contaminants in three environmental scenarios water leaching exposure to oxidising and reducing conditions was quantified by combining sequential extraction and waste mass the amounts of mobile contaminants that could be released for every tonne of phosphogypsum are approximately 7 10 2 g sr 1 1 10 2 g fe 55 g y 30 g ce 12 g cr 11 g ti 5 g zn 4 g each of cu and pb 3 g each of v and cd 2 g each of as and ni and 1 g u multiplying these amounts by 100 mt and 20 25 t ha it is possible to calculate risk assessments of phosphogypsum for both estuarine zones e g in a hypothetical stack collapse and waste spilling and agricultural soils respectively

regional wave propagation in china and its surrounding regions a comprehensive study of the gross characteristics of high frequency seismic wave propagation in china and its surrounding regions was accomplished to learn more about how regional geology affects high frequency phases amplitudes of the regional seismic waves sn and lg relative to p coda were used to map lateral variations of shear wave attenuation in the crust and upper mantle over 7000 digital seismograms from 13 broadband stations of the chinese digital seismic network and global seismic network in the frequency range 0 5 to 5 0 hz were visually examined propagation efficiencies of sn and lg were qualitatively analyzed by ranking their amplitudes relative to the p wave coda efficient sn propagation is observed in the tien shan tarim platform southern tibet yangzi paraplatform and sino korean platform we have confirmed results of previous studies by finding a lack of sn transmission in north central tibet the ryukyu and japan arcs burma and the baikal rift an important observation which has not been previously reported is that sn does not propagate across mongolia the elimination of sn and the occurrence of recent volcanism in north central tibet and mongolia suggest that there is partial melt in the uppermost mantle beneath those regions high frequency lg waves propagate efficiently for most of china indochina and mongolia lg signals are attenuated within central tibet as well as along its southern boundary crustal structure variations along with an anomalously low q crust are primarily responsible for weakened lg amplitudes in tibet propagation paths across oceanic crust in the sea of japan and the andaman sea show blockage of the lg phase as well this investigation has relevance to comprehensive test ban treaty monitoring by showing where certain regional phases will or will not propagate efficiently

hydrothermal precipitates associated with bimodal volcanism in the central bransfield strait antarctica polymetallic sulfide sulfate mineralization enriched in pb ag as sb hg occurs in the bransfield strait a late tertiary quaternary marginal basin close to the antarctic peninsula the mineralization is associated with bimodal volcanism and pelagic and volcaniclastic sediment in rifted continental crust hydrothermal precipitates have been recovered from two shallow 1 050 1 000 m water depth submarine volcanoes hook ridge and three sisters in the central bransfield strait mineralization at hook ridge consists of polymetallic sulfides massive barite and pyrite and marcasite crusts in semilithified pelagic and volcaniclastic sediment native sulfur commonly infills void space and cements the volcaniclastic sediment the polymetallic sulfides are dominated by sphalerite with minor galena enargite tetrahedrite tennantite pyrite chalcopyrite and traces of orpiment cemented by barite and opal a the presence of enargite at hook ridge the abundance of native sulfur and the low fe content of sphalerite indicate a high sulfur activity of the hydrothermal fluids responsible for mineralization the sulfur isotopic composition of hook ridge precipitates documents the complexity of the sulfur sources in this hydrothermal system with variable influence of biological activity and possibly magmatic contributions homogenization temperatures and salinities of fluid inclusions in barite and opal a suggest that boiling may have affected the hydrothermal fluids during their ascent the discovery of massive barite silica precipitates at another shallow marine volcano three sisters volcano attests to the potential for hydrothermal mineralization at other volcanic edifices in the area the characteristics of the mineralization in the bransfield strait with rifting of continental crust the presence of bimodal volcanism including highly evolved felsic volcanic rocks the association with sediments and the pb ag as sb hg enrichment are similar to the setting of massive sulfide deposits in the okinawa trough and distinct from those of sediment dominated hydrothermal systems such as escanaba trough middle valley and guaymas basin the geological setting of the bransfield strait is also broadly similar to that of some of the largest volcanogenic massive sulfide deposits in the ancient record such as the iberian pyrite belt

synchrotron based x ray study of iron oxide transformations in terraces from the tinto odiel river system influence on arsenic mobility simultaneous analysis of micro x ray diffraction xrd and micro x ray fluorescence xrf based on synchrotron light sources and electron microprobe emp analyses were performed on iron terrace samples taken from tinto odiel river system from the iberian pyrite belt ibp sw iberian peninsula iron terraces are formed during the oxidation and precipitation of dissolved iron along the riverbeds impacted by acid mine drainage amd this paper includes the study of actively forming current terraces and fossil terraces isolated from the stream courses due to the river migration over time the results of the study of current terrace samples from amd affected streams of two ipb abandoned mines tinto santa rosa and cueva de la mora showed that fresh precipitates at the surface are composed primarily of metastable schwertmannite which is gradually transformed at depth over short time scales into goethite sediments of ancient terraces are composed mainly of goethite which most likely originated from the re crystallization of a precursor schwertmannite however at century time scale goethite partially re crystallizes to hematite due to diagenetic processes the transformation rate of goethite into hematite is negatively correlated with grain size and the crystallinity of goethite moreover this transformation is accompanied by an increase in grain size and a decrease in surface area of hematite and a concomitant decrease in arsenic trapped in the solid this increase in the arsenic mobility during the diagenetic maturation should be considered in the development of conceptual and analytical models describing long term fate transport and bioavailability of arsenic in environmental systems

australian volcanic hosted massive sulfide deposits features styles and genetic models the cambro ordovician period has yielded the major development of volcanic hosted massive sulfide vhms deposits in australia resulting in about 12 million metric tons of contained metal copper lead and zinc concentrated in the mount read volcanics tasmania and the mount windsor volcanics queensland the archean 4 million metric tons of metal and the silurian 3 5 million metric tons of metal constitute the next important episodes while the devonian and permian have produced isolated deposits the deposits range from cu type to zn cu type to zn pb cu type the zn cu type deposits are restricted to the archean and silurian whereas the cu type and zn pb cu type occur sporadically throughout the time span from early archean to permian in general terms the major vhms bearing districts are calc alkaline in character and display a thick basal pile of rhyolitic volcanics 1 3 km thick including lavas epiclastics and subvolcanic intrusions which is overlain by a polymodal sequence containing various proportions of rhyolite dacite andesite basalt and sediments the major deposits are commonly located at the top contact of the rhyolite pile or within the lower part of the overlying polymodal sequence there is a wide range in variability of styles of australian vhms deposits including mounds pipes sheets layered deposits stacked deposits stockwork and disseminated deposits distal reworked deposits and cyclic layered deposits although these various styles show a range of features there is a consistent theme across the spectrum of metal zonation alteration mineralogy alteration chemistry sulfur isotopes macrotextures microtextures and host volcanic relationships which strongly suggests that they all belong to the one genetic group of ore deposit the classic mound style deposits such as hellyer have a series of key features subsets of which are represented in the other deposit styles the mound deposits are considered to form from deposition of metal sulfides on the sea floor immediately around the hydrothermal vent growth of the mound occurs by upward replacement of sulfide assemblages stable at higher fluid temperatures leading to zone refining and lead zinc silver gold enrichment in the outer and upper parts of the mound departure from the classic mound style of deposit is related principally to three key factors the chemistry of the ore fluid salinity temperature f02 and ah2s the nature permeability and chemistry of the volcanic pile and the sea hoor environment sea hoor topography and seawater depth these factors control the aspect ratio of the deposit the extent of stringer zone development the degree of subsea floor replacement mineralization the nature and spatial development of footwall alteration and the development and style of related distal mineralization sulfur isotope studies of australian vhms deposits indicate that reduced seawater sulfate is a major source of sulfur in the deposit whereas lead and strontium isotope results are compatible with the metals being derived by seawater convection and leaching from the volcanic pile and basement rocks this conclusion is supported by the application of various leaching models which demonstrate the availability of an adequate source of both base and precious metals in the footwall volcanic sequences the input of metals directly from volcanic magma chambers is not precluded by the available data and one likely scenario involves the contribution of gold and copper from a magmatic vapor plume rising to mix with convective seawater fluids which contribute lead zinc silver and gold leached from the footwall volcanics and basement rocks the relative importance of the magmatic input compared with the seawater convective input may help to explain the spectrum of deposit styles arid their spatial relationship to volcanic centers or adjacent sedimentary basins

provenance and geochemistry of sedimentary components in the volcano sedimentary complex iberian pyrite belt discrimination between the sill sediment complex and volcanic pile models two highly contrasting models have been proposed for the palaeovolcanological setting of the massive sulphide deposits in the iberian pyrite belt the long standing view of the host rocks is that they are a pile of effusive and pyroclastic rocks but this position has now been challenged by the proposal that high level peperitic sills predominate discrimination between the volcanic pile and sill sediment complex models is important because they lead to very different conclusions about such key metallogenic features as the timing of mineralization the nature of the ore forming convective system and the source of the metals sedimentary geochemistry particularly ree and ti nb shows that there is no correspondence between the chemistries of mafic igneous sheets and intercalated stratified volcaniclastic rocks that range from andesite to rhyodacite in composition therefore none of the mafic sheets supplied detritus to the sedimentary environment sedimentary rocks of continental provenance persist throughout the host rock sequence especially in mineralized regions implying confinement of the majority of primary volcanic facies in the form of high level intrusions some andesitic and felsic intrusions created a minor stratified volcaniclastic component via hydrovolcanic eruptions the volcanic pile model is invalidated because the expected provenance patterns for this volcanic style are not present and the sill sediment complex setting of the sulphide deposits is confirmed

crustal in south korea using the source pair receiver pair method graphic 1 has been studied extensively because its regional variations reflect geological structure values around 1 hz show close correlation with tectonic seismicity we analyze graphic 2 in south korea by applying the source pair receiver pair sprp method to 39 korean earthquakes and 32 far regional earthquakes we obtain nearly 1500 source receiver pairs with the combined difference of epicentral distance d ranging from 16 to 657 km seismograms are filtered by using an eight pole bandpass butterworth filter with five center frequencies 0 375 0 75 1 5 3 and 6 hz the obtained graphic 3 for all frequencies are less than 0 002 which is a reasonable value for a seismically inactive region in spite of the short range of d the results of the sprp method show reliable values especially at 1 5 and 3 hz 1 embed inline graphic 2 gif 2 embed inline graphic 3 gif 3 embed inline graphic 4 gif

a definitive approach to turbulence statistical studies in planetary boundary layers abstract a method for comprehensive statistical data analysis is presented it includes a procedure for selection of segments within a data record where data can be considered stationary allowing the computation of statistical parameters from data over selected segments and their confidence intervals estimating the statistical reliability of the parameters the method is illustrated by analysing the vertical component of the wind velocity data collected by research aircraft flights over lake michigan during project less lake effect snow studies the results indicate that for skewness and kurtosis the requirements for acceptable averaging distances are less limiting than the required distances for corresponding third and forth order moments

lead isotope systematics of the giant massive sulphide deposits in the iberian pyrite belt lead isotope analyses were performed on 26 polymetallic massive sulphide deposits of the iberian pyrite belt as well as on overlying gossans and associated volcanic rocks all the massive sulphide deposits except for neves corvo and nearly all the volcanic rocks show very similar isotopic compositions grouped around 18 183 206pb 204pb 15 622 207pb 204pb and 38 191 208pb 204pb indicating that most of the ore deposit lead was derived from the same continental crust environment as the associated volcanic rocks the isotopic compositions are representative of the average south iberian crust during the devonian to early carboniferous dinantian and their constancy implies a homogenization of the mineralizing fluids before the deposition of the massive sulphides from hydrothermal fluids circulating through interconnected regional fracture systems this isotopic constancy is incompatible with multiple small independent hydrothermal cells of the east pacific rise type and fits much better with a model of hydrothermal convections driven by magmatic floor heating neves corvo is the only south iberian massive sulphide deposit to have a heterogeneous isotopic composition with in particular a highly radiogenic stanniferous ore 206pb 204pb of the cassiterite is 18 40 a model of lead mixing with three components is proposed to explain these variations 1 one derived from the devonian to early carboniferous dinantian continental crust that generated all the other massive ores 2 an eohercynian stanniferous mineralization partly remobilized during the formation of the massive sulphides but independent of them and 3 a precambrian continental crust component the juxtaposition of three different sources places neves corvo in a specific paleogeographic situation that could also explain its mineralogical specificity the geodynamic context that best explains all the obtained isotopic results is one of an accretionary prism the fact that lead isotope signatures of the gossans are almost identical to those of the underlying massive sulphides means that this technique could be a useful exploration tool for the iberian pyrite belt

the 20 january 2007 odaesan korea earthquake sequence reactivation of a buried strike slip fault the m w 4 6 odaesan korea earthquake of 20 january 2007 11 hr 56 min had nine locatable foreshocks in the previous 67 hours and nine aftershocks during the 11 hours after the main event we obtained accurate locations of this sequence by employing the double difference earthquake relocation method with differential travel time measurements using waveform cross correlation we found that 19 accurately relocated foreshocks mainshock and aftershocks aligned along a 1 2 km long lineation with an azimuth of west northwest east southeast 115 which coincides with a nodal plane of the mainshock focal mechanism that strikes 114 regional waveform modeling of the mainshock constrained a focal depth of 11 1 km and the focal mechanism is a pure strike slip faulting along the vertical nodal planes with a horizontal p axis plunge 1 trending east northeast 69 the pulse rise time of the mainshock source time function estimated from an empirical green s function analysis ranges from 0 1 to 0 16 sec which yields a source radius of 0 6 km and is consistent with the spatial distribution of the foreshock and aftershock sequences the stress drop of graphic 1 is obtained for the mainshock using a radius of 0 6 km for a circular rupture and seismic moment graphic 2 the 20 january 2007 odaesan earthquake may be the first significant earthquake in southern korea to date where the fault plane is constrained by accurate locations of the foreshock and aftershock sequences its source mechanism vertical strike slip fault at depth suggests that the event represents reactivation of a buried high angle fault in the precambrian basement by the contemporary east east northeast trending regional horizontal compressive stress 1 embed inline graphic 1 gif 2 embed inline graphic 2 gif

postvolcanic paleozoic of the iberian pyrite belt an example of basin morphologic control on sediment distribution in a turbidite basin abstract the iberian pyrite belt south portuguese zone hercynian chain an important metallogenic province has a volcanic sedimentary origin overlying this volcanic succession is a thick sedimentary unit the culm group which represents postvolcanic paleozoic sediments of the iberian pyrite belt it consists of three stratigraphic units the basal shaly formation bsf the culm facies turbiditic formation cftf and the shallow platform sandy unit spsu the bsf is represented by finegrained sediments of volcanic to nonvolcanic origin that mark the end of volcanism in the region the reworking of volcanic products in a shallow marine basin and the beginning of autochthonous sedimentation of pelagic clay it constitutes a depositional sequence sensu mitchum et al 1977 the d stribution facies and facies associations of the turbidites of the cftf are related to the configuration of the basin which controlled the mechanisms of deposition and distribution of the detritus from different source areas the spsu represents sediments eroded from the volcanic upland and redistributed over the shelf detailed study of these three units and their relationships provides the means to define the geometry and evolution of the postvolcanic carboniferous basin of the iberian pyrite belt the basin was roughly subdivided by the paymogo and the puebla de guzman paleoridges together with the allochthonous ossa morena zone north of the study area they formed three topographic barriers that delineated two interconnected subbasins sedimentation in the postvolcanic basin of the iberian pyrite belt can be related to a model of oscillating sea level synorogenic characteristics of the culm group sediments support a tectonic origin for the sea level oscillations particularly since the sediments had already been affected by the first pulses of the hercynian orogeny

the 9 february 2010 siheung korea earthquake sequence repeating earthquakes in a stable continental region the 9 february 2010 m w 3 1 siheung earthquake occurred close to the metropolitan seoul city in the central korean peninsula and was widely felt by residents in seoul the shock occurred at a depth of 12 km in precambrian crystalline bedrock with predominantly strike slip faulting on a near vertical fault plane striking east southeast west northwest a rupture radius of 0 12 0 01 km is estimated for the m w 3 1 shock with a stress drop of 15 2 mpa sixteen small repeating earthquakes spread in time up to about five and a half years are detected based on their waveform similarities in a stable continental region setting these shocks cluster along a trend striking 110 which suggests a nodal plane of the mainshock focal mechanism striking n109 is the likely fault plane the repeating events around siheung korea show a recurrence interval of 0 77 0 37 year event for shocks of magnitude range m w 0 6 3 1 the waveform cross correlation detector provided identification of small repeating earthquakes with similar waveforms on an expanded time window which may suggest the existence of such repeating earthquakes in stable regions worldwide with relatively low seismicity such data may lead to improvements in delineating seismogenic features understanding the earthquake source properties and evaluating the earthquake hazards associated with infrequent occurrence of such earthquakes in stable regions online material figures showing locations from hypoinverse single event location and double difference methods and source time functions determined using empirical green s function analysis

chemical controls on the composition of vent fluids at 13 11 n and 21 n east pacific rise six vent fields sampled at 13 11 n east pacific rise epr in may 1984 exhibit large interfield variations and a much wider range of chemical compositions than previously observed at 21 n measured ph at 25 c are acidic ranging from 3 1 to 3 7 sodium and chloride vary from 40 lower to 30 higher than seawater iron concentrations range from 2 to 10 mmol kg compared with 0 7 2 5 mmol kg at 21 n other sulfide forming metals cu zn cd and pb are generally lower at 11 13 n than at 21 n reliable temperature measurements were obtained at only two of the six vents and both were 350 5 c the vent fields at 21 n epr were resampled in august 1985 thus extending to almost 6 years the time period over which they have been monitored previous expeditions were made in november 1979 and november 1981 campbell et al this issue have shown that the chemistry of the hydrothermal fluids from these fields has been very stable over the period of repeated observation equilibrium calculations for the fluids from the fields at 13 n and 21 n using a greatly improved thermodynamic data base are described in this report they indicate that the chemistry is rock buffered and that the stability of these systems over time is a result of equilibrium control with respect to a greenschist type mineral assemblage at depth calculated high temperature ph of the fluids range from 4 1 to 4 7 with those from 13 11 n at the more acidic end of the range calculated affinities show that the fluids are close to or at saturation with respect to quartz albite muscovite smectite chlorite epidote and pyrrhotite the computations imply that lower temperature vents such as national geographic smoker ngs 273 c may have their silica concentrations controlled by equilibrium with respect to a phase other than quartz a comparison of fluid chemistry between ngs and vent 5 at 11 n suggests that the latter vent may also have a temperature 300 c while the fluid chemistry of a given field is compositionally stable the compositions themselves are unique for a particular field and cover a wide range between fields the processes controlling this variability probably include the depth of reaction i e pressure which is difficult to treat thermodynamically at present in addition increasing depth in the crust may be accompanied by decreasing permeability and hence a probable decrease in the water rock ratio it may be difficult to separate these two effects if the age differences between the fields at present unknown are of the order of decades then their temporal histories may have an important influence on their particular chemistries

variations in regional phase propagation in the area around japan the high level of seismicity and dense network of short period stations in japan allows a detailed characterization of regional phase propagation there are substantial differences depending on the location of the source and stations despite the structural complexity lg is clearly seen in many parts of japan lg is particularly well developed in the western part of the main island honshu and will propagates through some volcanic zones with loss of high frequency components there are also zones of lg blockage in northeastern honshu and for subduction zone events with significant oceanic paths for which the mantle phases pn and sn are particularly clear the oceanic region in the sea of japan blocks lg propagation paths for events in mainland asia at many stations but there are clear lg propagation corridors through korea to stations in the west kyushu western honshu and in the north into hokkaido the lg phase carries substantial energy for large events and the differences in efficiency of propagation influences the intensity of ground shaking thus the 1995 hyogo ken nanbu kobe earthquake shows intensity contours extended to the west in the region of efficient lg wave propagation the rg phase and the fundamental mode of love waves are very significant for the shallow 2000 tottori ken seibu event and the effect of the combination of lg with these slightly lower frequency surface waves would help to explain the discrepancy between the japan meteoro logical agency magnitude from regional stations mj 7 3 and the moment magnitude from distant observations m w 6 6

gold behavior in supergene profiles under changing redox conditions the example of the las cruces deposit iberian pyrite belt the las cruces deposit is in the eastern end of the iberian pyrite belt sw spain it is currently being mined by cobre las cruces s a the main operation is focused on the supergene cu enriched zone initial reserves of 17 6 mt 6 2 cu an au ag pb rich gossan resource 3 6 mt 3 3 pb 2 5 g t au and 56 3 g t ag occurs in the upper part of the deposit the au grade ranges from 0 01 ppm to 100 ppm and occurs as three different au ore types 1 au mineralization in the upper part of the gossan linked to fe oxides lithofacies 2 au concentration in the lower part of the gossan associated with leached black shales and 3 au ore in the cementation zone related to subvertical fractures a hydroseparation device has been used to obtain heavy mineral concentrates from selected samples of different ore types reflected light microscopy scanning electron microscopy energy dispersive spectroscopy sem eds and electron probe microanalysis epma were used to study the separated au particles significant differences between the defined ore types include the au bearing lithologies mineral associations textural features particle sizes morphologies and fineness au rich minerals include native au au ag electrum and au ag hg amalgams gold bearing mineral associations include pb oxihalides fe oxides galena pyrite cinnabar and ag sulfosalts the au enrichment mechanism in the supergene profile involves 1 dissolution of au from the primary sulfides as chloride rich ionic complexes during the weathering of the deposit under subaerial exposure dissolved au is transported downward through the supergene profile under acidic and oxidized conditions 2 destabilization of the au complexes by fe controlled redox reactions as a consequence coarse grained high fineness au particles precipitated in association with fe oxyhydroxides this resulted in secondary concentration in the upper gossan and 3 after deposition of cover sediments took place a progressive change in the system conditions resulting in a later au remobilization as hydroxidehalide hydroxide thiosulfate and bisulfide complexes in the lowermost gossan and cementation zone the main pathways for migration of enriched fluids to the cementation zone are secondary permeability zones linked to alpine reactivated faults deposition of au seems to be related to fluid interaction with reductant lithologies including black shales and the primary sulfides

geological constraints on the paleozoic tectonic evolution of tectonostratigraphic terranes in the iberian massif abstract the presence of oceanic paleozoic sequences in the iberian variscan fold belt is used to identify and separate suspected exotic terranes from a reference iberian autochthon terrane which constitutes the greater part of it in this paper the relevant data characterizing the pre accretionary evolution of the paleozoic iberian terranes are presented as well as the available evidence concerning the accretionary process itself emphasis is placed on the analysis of the sedimentary igneous and structural expression of the major events which affected the iberian terranes before during and after their amalgamation the main conclusions of such an analysis may be summarized as follows 1 a recognition of rift and passive margin stages in all the iberian massif terranes during the early paleozoic 2 b late paleozoic accretion of the exotic terranes to the iberian autochthon via a long and complex process variscan orogeny which involved initial subduction underneath the latter and eventual obduction followed by oblique collision of a promontory the iberian autochthon northwestern margin with a northwestern continental block this latter process could account for the large scale crustal imbrication shown by the northern branch of the orogen coeval with predominant strike slip faulting in the southern branch as well as with the formation of the typical arcuate shape of this orogenic belt major present uncertainties relate to the palinspastic provenance of continental suspect terranes and their correlation with similar units in other circum atlantic paleozoic orogens a discussion and speculations on this subject are dealt with in the final section of this paper

1 18 hz lg attenuation in the granada basin southern spain summary the attenuation of the lg waves for the granada basin has been analysed this study has been done in the frequency domain eliminating the influences of the source the instrumental response and the local site response using the reverse two station method rtsm the average qlg value for the whole region obtained for all the paths is qlg 105 25 0 93 0 14 the average values of qlg determined for this region are lower than those corresponding to other areas of spain and are similar to those of coda q obtained using local coda and single scattering methods for some determined focal depth and for some lapse times 50 and 70 s small differences of the attenuation are observed between paths that cross the central part and the edges of the basin a detailed analysis showed that the e w and the n s directions have differences between attenuation values in the e w direction q0lg the qlg value at 1 hz of frequency is 131 7 and in the n s one q0lg is 88 21 the frequency dependence is similar to the average qlg value these values may indicate that the attenuation of the lg waves at least for this region may not be affected by only the anelastic dissipation but also by scattering process the n s direction is normal to the dominating fault systems and seems to provide a greater scattering effect than the e w direction

attenuation of 1 6 s lg waves in eurasia we report our investigation of the lg attenuation characteristics in eurasia using digital recordings from the incorporated research institutions for seismology chinese digital seismic network broadband stations to maximize the utilization of the current station and source distribution in the region we have derived a new technique known as the source pair receiver pair sprp method for lg attenuation measurement the procedure eliminates seismic source and site effects leaving behind decontaminated amplitude data from which regional wave attenuation is estimated for lg attenuation studies the sprp method is more flexible and of greater general applicability than its predecessor the reversed two station method chun et al 1987 the application of the sprp method to our time domain analysis of 33 regional and far regional seismic events has provided stable regional average for lg attenuation in periods of 1 6 s our time domain analysis aided by a damped least squares inversion algorithm has led to robust measurements of lg attenuation q and its frequency dependence in nine subregions of tectonic significance regions of active tectonics and seismicity generally have lower q0 than that in the stable continental interior subregional q and are found compatible with the published results in areas of relatively uniform geology values are comparatively poorly determined suggesting that they are susceptible to the presence of crustal heterogeneities along the wave paths

environmental tracers for elucidating the weathering process in a phosphogypsum disposal site implications for restoration summary this study provides geochemical data with the aim of identifying and tracing the weathering of phosphogypsum wastes stack piled directly on salt marshes of the tinto river estuary of huelva sw spain with that purpose different types of highly polluted acid solutions were collected in the stack connection between these solutions and the estuarine environment was studied by geochemical tracers such as rare earth elements ree and their north american shale composite nasc normalized patterns and cl br ratios phosphogypsum related wastewaters include process water stored on the surface pore water contained in the phosphogypsum profile and edge outflow water emerging from inside the stack edge outflow waters are produced by waterlogging at the contact between phosphogypsum and the nearly impermeable marsh surface and discharge directly into the estuary process water shows geochemical characteristics typical of phosphate fertilizers i e ree patterns with an evident enrichment of heavy ree hree with respect to middle ree mree and light ree lree by contrast ree patterns of deeper pore water and edge outflows are identical to those of tinto river estuary waters with a clear enrichment of mree relative to lree and hree denoting influence of acid mine drainage cl br ratios of these solutions are very close to that of seawater which also supports its estuarine origin these findings clearly show that process water is not chemically connected with edge outflows through pore waters as was previously believed phosphogypsum weathering likely occurs by an upward flow of seawater from the marsh because of overpressure and permeability differences several recommendations are put forward in this study to route restoration actions such as developing treatment systems to improve the quality of the edge outflow waters before discharging to the receiving environment

attenuation of high frequency shear waves in the crust measurements from new york state south africa and southern california we compare the attenuation of high frequency 3 30 hz shear waves for crustal paths in new york state south africa and southern california over source receiver distances of about 10 400 km the data consist of digital recordings of s waves 5 100 km and lg waves 100 400 km produced by earthquakes we use a coda normalization method to remove the effects of site amplification and source excitation from the amplitudes of the s and lg waves over the entire distance range studied 10 400 km the amplitude decay of 3 hz shear wave energy is considerably less for the tectonicaily stable areas of new york and south africa than for the tectonicaily active region of southern california high frequency 30 hz s wave attenuation is significantly less for new york and south africa than for southern california for distances between 15 and 90 km we parameterize the decay with distance r of coda normalized shear wave amplitudes with a frequency independent q and geometrical spreading exponent where geometrical spreading is proportional to r for new york state the s wave amplitude decay 3 30 hz is well described by a frequency independent q of 2100 330 490 and of 1 3 0 1 the decay of lg wave amplitudes from 3 to 15 hz in the new york state region is fit with a frequency independent q of 1600 280 330 of 0 70 0 2 the s wave amplitudes 3 30hz in south africa yield a q of 1500 190 380 and of 1 3 0 1 fixing the geometrical spreading at r 0 5 produces an lg wave q estimate at 3 hz in south africa of 360 50 80 this lg wave q is low considering that south africa is a cratonic tectonicaily stable area the s wave amplitudes from southern california are described with a frequency independent q of 800 150 240 and a large geometrical spreading exponent of of 1 9 0 2 we find an lg wave q at 3 hz of 260 30 for southern california after constraining the geometrical spreading at r 0 5

lg attenuation near the north korean border with china part ii model development from the 2006 nuclear explosion in north korea an underground nuclear explosion was set off on 9 october 2006 in north korea the event was recorded at near regional to regional distances over purely continental paths by a network of broadband seismographs located along the northern edge of the korean peninsula the event provided the first window of opportunity to make a reliable measurement of lg wave attenuation in northernmost north korea where the regional phase propagation characteristics are poorly known the results of our analysis show q0 317 14 and 0 343 0 024 in close agreement with the corresponding values obtained of late using a completely different methodology and an independent set of seismic recordings in an adjacent region to the northwest in southern jilin and in liaoning provinces in china

formation of a hardpan in the co disposal of fly ash and sulfide mine tailings and its influence on the generation of acid mine drainage abstract pilot scale field experiments were conducted to test a strategy for the treatment of acid mine drainage by addition of an alkaline cover of coal combustion fly ash on two sulfide mine tailings impoundments iberian pyrite belt sw spain during the pilot scale treatment calcium rich alkaline solutions from fly ash interacted with metal rich acidic solutions from the mine tailings leading to the massive precipitation of newly formed phases mainly in the fly ash close to the interface between both materials over time the interaction between fly ash and pyrite sludge promoted the formation of a chemically cemented zone or hardpan which was analyzed at high spatial resolution by micro x ray diffraction xrd and micro x ray fluorescence xrf based on synchrotron radiation these micro characterization techniques extensively identified poorly crystalline fe oxyhydroxysulfates jarosite and gypsum as newly formed phases in the hardpan and gypsum in the fly ash as deduced from principal component analysis of the fluorescence intensity data these phases seem to exert a significant mineralogical control on element mobility in particular jarosite showed high affinity for as whereas poorly crystalline fe rich assemblages selectively concentrated mn ni and pb sequential extractions indicated that the application of a fly ash cover significantly reduced the bioavailability of most of the elements by modification of their chemical speciation into less mobile forms under typical oxidizing conditions as an additional advantage the development of the hardpan hindered the penetration of oxidizing agents to sulfide mine tailings this effect significantly reduced the sulfide oxidation rates therefore attenuating the release of potentially pollutant elements to the environment

ore mineralogy and sulfur isotope study of the massive sulfide deposit of filon norte tharsis mine spain the volcanogenic massive sulfide deposit of filon norte at tharsis is hosted by carbonaceous black slate and connected only partly with stockwork veins the massive ores are usually composed of fine grained pyrite with subordinate amounts of sphalerite chalcopyrite galena and arsenopyrite monoclinic pyrrhotite sometimes occurs in massive pyritic ores in the apparently middle and upper horizons of the orebody and siderite rich ores are interstratified with compact pyritic ores in the apparently lower horizons from the occurrence of monoclinic pyrrhotite together with the fes contents of sphalerite mostly ranging from 11 to 16 mol it is inferred that the sulfide minerals of the massive orebody were precipitated in euxinic muds on the sea floor at temperatures below 250 c the negatively shifted highly variable 34s values of the massive ores and their close similarity to those of the underlying black slates strongly suggest that the sulfide sulfur of the massive orebody and the slates is cognate and biogenic

measurement of frequency dependent lg attenuation in the great basin measurement of the spatial decay of spectral amplitudes of the higher mode seismic surface wave train lg indicates that in the great basin the apparent seismic quality factor q is a function of frequency observations along a 300 km profile recording of a nuclear explosion yield the function q 206 0 68 over the band 0 3 10 0 hz similar analysis using numerous recordings of earthquakes along paths which provide a good average sampling of the great basin crust gives q 214 15 0 54 0 09 for 0 3 5 0 hz if the crustal sampling by lg energy from nuclear explosions surface sources is primarily in the shallow crust as has been suggested then these results indicate a greater frequency dependence of apparent q there than at depth

separation of intrinsic and scattering attenuation using single event source in south korea abstract simultaneous use of numerous events in the multiple lapse time window analysis mltwa method is the most effective way to obtain and values such simultaneous use of numerous events normally shows a large observational scatter which may be caused by different radiation pattern and focal depth of each earthquake and regional alteration of the local structure to avoid these scattering factors the current study attempted to use single event source as the input data in mltwa for south korea the direct simulation monte carlo dsmc method was used to simulate the observations which showed realistic results when the number of recorded stations was eight or more the obtained values of seismic albedo b 0 were less than 0 5 which were in accordance with the same in the previous results three envelopes constructed by combination of three regional values of at 1 hz produced regional variations of which the ones at high frequencies of and at low frequencies of were remarkable this result showing the local variation indicated an advantage of the study using single source event over the previous studies in south korea that involved extensively distributed data because dsmc was known to be applicable to 3d structure due to its simple algorithm the current study also tried to correct radiation pattern of the observations by inserting focal mechanism algorithm to the code of the dsmc method such insertion however generated extremely low values of because the geometrically shrunk receiver could not capture most of the scattered particles this receiver problem is most likely to be a major obstacle of the 3d study of dsmc in addition the significant depth effect of q 1 was identified for the prior mltwa studies resulting from different measurement range and focal depth

extreme 18o enriched volcanics and 18o evolved marine water aljustrel iberian pyrite belt transition from high to low rayleigh number convective regimes abstract quartz eye keratophyric tuffs at aljustrel s portugal iberian pyrite belt possess unusually high uniform whole rock values up to 18 1 with a mean of 16 7 0 7 because the quartz eye cores have 18o 12 0 to 13 5 the felsic tuffs may have had an original whole rock oxygen isotope composition of 10 to 11 the deduced enrichments of up to 8 in keratophyric derivatives is attributed to isotope exchange with abundant marine water under temperatures which diminished to 100 c during thermally driven convective cooling the isotopic uniformity requires elevated permeability of 10 8 cm2 such that the second critical rayleigh number was exceeded and drifting non steady state convection cells dominated with relatively smooth thermal structures in mineralised counterparts of the tuffs beneath the feitais estacao zn pb cu massive sulphide orebodies whole rock values are 12 and quartz 13 3 15 4 chlorite 3 2 6 3 fractionations correspond to temperatures of 220 270 c and a calculated fluid 18o of 1 4 to 5 7 this local isotopic overprinting in vent domains of the regionally high 18o was induced by a stable second stage convective regime imposed by drastic reduction of permeability accompanying capping of the geothermal discharge by hydrothermal cherts and or progressive spilitisation of the tuffs at lower water rock coupled with higher temperatures the recirculating marine water underwent variable 18o enrichment up to 5 7 by exchange with the high 18o tuffs an upwards increase in 18o quartz and quartz reflects progressive cooling of the geothermal discharge from 15 4 270 c in the stockwork through 18 3 220 240 c in the orebody to 20 1 110 130 c in overlying hydrothermal cherts probably induced by entrainment of ambient marine bottom water in sub seafloor aquifers

giant pyritic base metal deposits the example of feitais aljustrel portugal detailed study of hanging wall rocks and alteration above the giant feitais orebody of aljustrel iberian pyrite belt portugal shows that cherts that constitute the immediate hanging wall to the sulfide deposit result from hydrothermal alteration of laterally equivalent fe and or mn rich jaspers textures geochemistry and lack of fossil radiolarians indicate that these jaspers are hydrothermal precipitates hydrothermal alteration of the jaspers took place concomitantly with sulfide precipitation through reaction with hot 150 c reduced fluids with replacement of hematite by magnetite pyrite and fe2 phyllosilicates on the basis of the above and considering also the results of previous studies on hydrothermal activity in the aljustrel volcanic rocks and sulfide ores we propose that sulfide precipitation may have taken place under a thin veneer of siliceous sediments present day massive sulfide formation in the guaymas basin and in the salton sea under hundreds of meters of sediments may be approximate analogues in the sense that the presence of a caprock reduces dispersion of black smoke and causes more efficient precipitation

post depositional redistribution of trace metals in reservoir sediments of a mining smelting impacted watershed the lot river sw france abstract mining smelting wastes and reservoir sediment cores from the lot river watershed were studied using mineralogical xrd sem eds empa and geochemical redox dynamics selective extractions approaches to characterize the main carrier phases of trace metals these two approaches permitted determining the role of post depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals the mining smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals the main trace metal bearing phases include spinels affected by secondary processes silicates and sulfates the results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining smelting activities with the downstream sediments showing a 2 fold to 5 fold greater contribution of the oxidizable fraction this increase was ascribed to stronger post depositional redistribution of trace metals related to intense early diagenetic processes including dissolution of trace metal bearing phases and precipitation of authigenic sulfide phases through organic matter om mineralization this redistribution is due to high inputs derived from mining smelting waste weathering at the water sediment interface of i dissolved so4 promoting more efficient om mineralization and ii highly reactive trace metal bearing particles as a result the main trace metal bearing phases in the downstream sediments are represented by zn and fe sulfides with minor occurrence of detrital zincian spinels sulfates and fe oxyhydroxides sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural floods and or anthropogenic dredging dam flush events that might promote trace metal mobilization through sulfide oxidation it is estimated that during a major flood event about 870 t of zn 18 t of cd 25 t of pb and 17 t of cu could be mobilized from the downstream reservoir sediments along the lot river by resuspension induced oxidation of sulfide phases these amounts are equivalent to 13 fold cd 6 fold zn 4 fold pb the mean annual inputs of the respective dissolved trace metals into the gironde estuary

frequency dependent attenuation in the crust beneath central france from lg waves data analysis and numerical modeling abstract the quality factor of shear waves in the crust beneath central france is evaluated by the combined use of data analysis and theoretical modeling the measurement is made from lg wave records of 18 earthquakes at 22 short period vertical seismic stations of the french seismic network the geometrical attenuation of lg waves has been calculated through a numerical simulation in a perfectly elastic model the station responses including site effects have been evaluated from lg waves and from records of the seismic noise q has been calculated for a set of 11 frequencies between 0 5 and 10 hz and has been found to be in the form q 290 f 0 52 where f is the frequency the numerical simulation leads to the interpretation of q of lg waves as the mean value of q within the crust theoretical and experimental decay of energy with distance are in very good agreement the lg waves present a different sensitivity to a low q zone whether this zone is associated with the sediments or with scattering in the lower crust the lower crust beneath central france appears from our experimental results to be associated with high values of q

the separation of intrinsic and scattering seismic attenuation in south korea abstract for the separation of intrinsic and scattering attenuation in south korea coda observations represented by the multiple lapse time windows method were numerically simulated using the direct simulation monte carlo method the simulation showed that the depth dependent velocity model separated by crust and mantle fit better than the uniform velocity model under a uniform attenuation assumption the and total in south korea represent the lowest values among current global measurements these low attenuation values can be explained by the inactive seismicity of south korea corresponding to those of the seismically stable area such as a shield

spatial and temporal correlation between coda q and seismicity in china a map of coda q at 1 hz q was constructed for china by analyzing more than 1000 seismograms from 80 seismic stations distributed throughout china the resultant contour map of q shows a strong correlation with the epicenters of historic great earthquakes in china the high q regions are devoid of the epicenters and the low q regions are full of them a remarkably linear relation was found between the logarithm of coda q and the maximum earthquake within the area sampled by coda waves radius of about 150 km from each station when we consider earthquakes which occurred from 1700 to present roughly speaking if q is 1000 m max is about 4 and if q is 100 m max is about 8 this relation will be very useful for siting critical facilities such as nuclear power plants and waste disposal sites we also found evidence in support of the migration of low q region coincident with the well known migration of high seismicity region over the distance of several hundred kilometers during the period of several hundred years if the migration is due to a diffusion process the diffusion constant is of the order of 100 km2 yr which agrees very well with those associated with the aftershock migration fluid injection and vp vs anomaly comparison of coda q with q1 estimated from the intensity data shows that they agree very well for q1 150 supporting the validity of the s to s single backscattering model for coda waves for q1 150 however coda q becomes constant independent of q1 this behavior is qualitatively consistent with numerical experiments of frankel and clayton and suggests that coda q may be measuring the intrinsic q of about 150 for these regions where q1 150 this limiting coda q value may depend on regions because coda q lower than 100 has been observed in some active regions in this study and also coda q as low as 30 to 40 has been reported in california mexico and italy

gold mineralisations in the sw iberian pyrite belt the occurrence and distribution of gold in the massive sulfide orebodies of the upper palaeozoic volcano sedimentary environment of the sw iberian pyrite belt have long been assumed to be quite uniform recent investigations in several working mines indicate that the gold content of the ores varies between ore types and is controlled by physico chemical and time factors during deposition above average gold grades occur in the following ore types lead zinc rich ores situated laterally and on top of the massive sulfide lenses copper rich siliceous basal ore facies footwall stringer sulfides and gangue rich massive sulfides siliceous carbonate rich baryte bearing or carbonaceous matrix exploration possibilities therefore are promising in foot and hanging wall environments within an orebody as well as in disseminated and stringer ores in its footwall

regional variations of seismic attenuation from coda and l g waves in northern baja california attenuation of coda and lg waves was estimated from events recorded by the seismic network of northern baja california red sismica del noroeste de mexico resnom in the frequency band 1 to 12 hz in order to find a regional variation of qc crustal quality factor for s waves in northern baja california mexico we used the single scattering model of sato 1977 in the time domain to estimate quality factor qc and a spectral approach to relate acceleration spectra with distance to estimate the anelastic attenuation coefficient of lg waves we calculated qc for short 10 s and long lapse times 70 s using local events and the events that originated at the main tectonic features of the area assuming a frequency dependence of qc of the form qc qc we observed for short lapse times a regional variation of q0 with low values from about 53 in the inner continental borderland icb province to about 115 in the peninsular ranges pr and 144 in the gulf of california depression gcd province the values range from 0 70 and 0 85 for events in the icb and pr to 0 44 in the gcd region for long lapse times and for events located in the pr we found q0 values from 49 at stations within the icb to 101 at stations within the gcd attenuation coefficient of lg waves between 1 and 6 hz was also estimated using events located in southern california with source station distances up to 420 km we found that frequency dependence of was higher for source receiver paths going from a typical continental structure to a pull apart basin the gcd province than for paths within the pr using all data in a linear inversion process and assuming a group velocity vlg of 3 4 km s we obtained a power law dependence of the form qlg 288 20 0 32 02

attenuation characteristics of body waves for the bilaspur region of himachal lesser himalaya the attenuation characteristics around bilaspur region of the himachal lesser himalaya have been estimated adopting extended coda normalization method and using a data set of 41 local events 0 5 m l 2 9 that occurred in the region from may 2013 to march 2014 the frequency dependent relations governing the quality factors of p waves q and s waves q in the frequency range from 1 5 to 24 hz are q 43 4 f 1 30 0 04 and q 79 6 f 1 25 0 02 the average estimates of q and q are found to vary from 71 and 125 at 1 5 hz to 2901 and 4243 at 24 hz respectively the q and q estimates are compared to the similar estimates obtained for the other seismically active regions of the himalaya it is found that for the various himalayan regions the q estimates at 1 hz vary between 22 for the kumaon himalaya and 97 for the northwest himalaya whereas q estimates range between 63 for the garhwal himalaya and 127 for the northwest himalaya for the bilaspur region the q q ratio is greater than unity and varies between 1 84 and 1 45 in the frequency range from 1 to 24 hz the region specific attenuation relations can be adopted for estimating earthquake source parameters simulating strong ground motion and assessing seismic hazard for the bilaspur region of himachal lesser himalaya

phyllosilicates and associated minerals in some paleozoic stratiform sulfide deposits of southeastern australia the pb zn ores of eight of the nine deposits are characterized by one or the other of the phyllosilicate assemblages chlorite talc phlogopite biotite or chlorite muscovite the other contains chlorite phlogopitic trioctahedral mica but no talc phyllosilicate mineral chemistry is highly systematic and is related to ore type and ore stratigraphy in all cases chemical equilibrium between the phyllosilicates has been approached on a small scale equilibria were established substantially at the sedimentary early diagenetic stage the phyllosilicates were deposited as chemical precipitates in the hydrothermal aprons at the time of sea floor exhalative activity subsequent metamorphism has done little more than perfect crystal structures and coarsen grain size modified journal abstract

variability of crustal attenuation in the northeastern united states from lg waves high quality digital seismograms from eight pairs of collocated earthquakes in the northeastern united states were analyzed to determine accurate source spectrum corner frequencies this was accomplished by applying the empirical green s function method to regional pg and lg or sg phases recorded by vertical component seismographs of the u s national seismographic network usnsn and the lamont doherty cooperative seismographic network lcsn stations the frequency band used was 0 5 16 hz for usnsn and 1 30 hz for lcsn records the source spectrum corner frequencies for the eight larger earthquakes of the event pairs magnitudes between mb lg 2 5 4 1 range from about 4 3 to 16 3 hz based on the comer frequencies obtained independently from the empirical green s function analysis sg or lg wave displacement amplitude spectra up to 30 hz were used to determine the crustal average q factors along 87 event station paths these paths crossed diverse tectonic features in the northeastern united states and were in the epicentral distance range of 41 to 1394 km we found that within the northeastern united states the crustal average qlg we obtained was frequency dependent and showed spatial variability which correlated fairly well with the major tectonic features in the region our attenuation measurements indicated low lg attenuation in the adirondack mountains with exposed precambrian grenville basement with qlg 905 f0 40 high lg attenuation in the central appalachian province with qlg 561 586 f0 46 0 47 and an intermediate lg attenuation in northern new england appalachians with q 705 f0 41

frequency dependent attenuation in eastern kazakhstan and implications for seismic detection thresholds in the soviet union abstract the frequency dependent attenuation of regional seismic phases recorded by three stations near the nuclear explosion test site in eastern kazakhstan is estimated by inverting spectra from 21 events with magnitudes between 2 3 and 4 6 at distances between 200 and 1300 km the pn spectra are inverted between 1 and 10 hz and the lg spectra are inverted between 0 5 and 2 5 hz the motivation for this study is that previous estimates of detection capability in the soviet union are based on data recorded in other regions eastern north america and scandinavia and therefore have large uncertainty the data recently recorded in eastern kazakhstan provide an excellent opportunity to compare regional wave propagation and noise characteristics at these sites to conditions assumed in previous detection capability simulations it is found that attenuation in eastern kazakhstan is not much different from attenuation in scandinavia but it is greater than attenuation in eastern north america this implies that estimates of detection thresholds that assume attenuation like that observed in eastern north america will be lower than estimates of detection thresholds that assume attenuation like that observed in eastern kazakhstan or scandinavia however it is not known how well data recorded in eastern kazakhstan represent conditions in other areas of the soviet union

use of sequential extraction procedure for assessing the environmental impact at regional scale of the sao domingos mine iberian pyrite belt sao domingos is one of the most emblematic portuguese mining districts in the iberian pyrite belt ipb the beginning of mining exploitation in the area has been dated back to pre roman times remaining in activity until 1966 when it was definitely halted the intense mining labours are reflected in the presence of a huge amount of sulphide mining wastes and downstream production of acid mine drainage amd the mining wastes in the area are highly heterogeneous and numerous different types may be recognized including slags iron oxides smelting ashes brittle and blocks of pyrite leaching tank refuses industrial landfill and other residues coming from ore extraction gossan wastes and country rocks the chemical speciation of potentially toxic elements as cd cr cu fe mn pb s sb and zn in all mine wastes from sao domingos was determined by modified bcr sequential extraction procedure european community bureau of reference and combined with the mass volume proportions of each waste to quantify the potential risk of this mining district at regional scale analytical recoveries by sequential extraction with respect to a pseudo total metal content digestion were generally acceptable 100 17 the oxidizable fraction corresponds with metals bound to sulphides and released easily under oxidizing conditions in amd production processes this is the most polluting fraction for the environment in this type of residues part of this fraction is retained by precipitation of soluble secondary minerals in warm periods moving to the bio available fraction that is dissolved in rainy periods just considering the bio available fraction all mine wastes from sao domingos may leach up to 172514 ton of fe 10564 ton of s 6644 ton of pb 2610 ton of zn 1126 ton of mn 1032 ton of cu 183 ton of cr 109 ton of as 34 ton of sb and 0 9 ton of cd the process of precipitation and re dissolution of efflorescent salts formed directly by oxidation of the oxidizable fraction is seasonally repeated which causes an annual self feeding and releasing of the bio available fraction thus the present study shows the pollutant potential of this ipb mining district and explains the spoiled state of the fluvial courses in the region

regional variations of seismic attenuation of lg waves in southern mexico attenuation of lg waves is estimated using 61 events located in the subduction zone of the middle american trench and recorded by the seismic network of laguna verde veracruz mexico we estimate the anelastic attenuation coefficient of lg waves or equivalently qlg by calculating the rate of acceleration spectra decay with distance we consider paths from two regions guerrero veracruz ne sw direction and oaxaca veracruz north south direction assuming a frequency dependence of of the form 0 we find that 0 175 0 05 for both regions and that 0 was lower for paths from guerrero to veracruz 0 0 0071 0 002 than for paths from oaxaca to veracruz 0 0 0161 0 003 in the frequency range from 2 to 7 hz in terms of the quality factor qlg values of qlg 134 30 0 83 0 2 and qlg 59 10 0 81 0 2 were found for the guerrero veracruz and the oaxaca veracruz paths respectively this difference in attenuation may be due to the state of stresses that prevails in both regions including the density and fluid content of fractures which are attenuation mechanisms also suggested for other regions mitchell 1995