decay constant errors in u pb concordia intercept ages abstract although almost universally ignored the effect of errors in the uranium decay constants on u pb concordia intercept ages and pb pb ages are significant and not equivalent to those of simple u pb ages equations are derived for concordia intercept age errors that take decay constant errors into account

first record of seymouria vertebrata seymouriamorpha from early permian fissure fills at richards spur oklahoma isolated skeletal elements of the amphibian genus seymouria were recently discovered at the richards spur locality near fort sill oklahoma a prolific source of early permian tetrapod remains five of the seven described bones are of juvenile size and include three neural arches a humerus and a femur whereas the other two are partial vertebrae apparently adult all seven are morphologically similar to equivalent skeletal elements in seymouria specimens previously collected in europe and north america apart from features reflecting the early developmental stage of the juvenile bones the femur and humerus are clearly distinct from those of other seymouriamorphs such as ariekanerpeton and kotlassia the rarity of seymouria at the richards spur locality implies that it was not a regular component of the fauna and it is also associated with the less markedly terrestrial assemblage that consistently occurs at localities in the southwestern united states however its skeletal morphology and occurrence a

derivation of isotope ratios errors and error correlations for u pb geochronology using 205pb 235u 233u spiked isotope dilution thermal ionization mass spectrometric data a comprehensive treatment of the derivation of u pb isotope ratios and their corresponding uncertainties from isotope dilution thermal ionization mass spectrometric measurements is presented standard parametric statistical methods of error propagation are utilized to convolve uncertainties associated with instrumental mass fractionation tracer subtraction blank pb and u subtraction and initial common pb correction derivations include errors and error correlations for total sample u pb and pb isotope ratios including radiogenic and initial common pb for two and three dimensional isochron calculations radiogenic u pb and pb isotope ratios for concordia and radiogenic model age calculations and the propagation of model age errors from radiogenic isotope ratios

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

secondary copper enrichment in tailings at the laver mine northern sweden field and laboratory studies of the sulphide bearing tailings at laver northern sweden show that the present release of metals from the tailings is low especially with regard to cu a large part of the cu released by sulphide oxidation is enriched in a distinct zone just below the oxidation front the enrichment zone occurs almost all over the tailings area except in areas with a shallow groundwater table the cu enrichment is caused by formation of covellite and adsorption onto mineral surfaces the transport of zn co cd ni and s seems to be controlled mainly by adsorption no secondary zone or secondary minerals containing these metals have been found just below the groundwater table metals are released into solution when the enrichment zone reaches the groundwater due to the low ph an increased release of metals especially cu can be expected in the future since the enrichment zone is moving towards the groundwater table

cross equatorial response to middle latitude forcing in a zonally varying basic state abstract a nonlinear model based on the shallow water equations is used to study cross equatorial propagation of forced waves in the presence of a longitudinally varying time mean basic state zonal wind field it is found that global scale planetary waves are unable to propagate past a critical latitude where the mean zonal wind speed vanishes however if the longitudinally asymmetric basic state includes a duet in which the zonal winds are westerly waves of zonal scale less than the zonal scale of the westerly duct may propagate from one hemisphere to the other even though the zonally symmetric mean zonal wind remains easterly in the equatorial region the amplitude of the response in one hemisphere to forcing in the opposite hemisphere increases strongly with the magnitude of the westerlies in the equatorial duct the existence and annual variations of a westerly duct region in the upper troposphere in the eastern pacific appear to account for some features of the low frequency variability in the no

characteristics of atmospheric circulation over east asia associated with summer blocking the boreal summer blocking regions were defined using the reanalysis data over the three decades of 1981 2010 and the influence of the blocking on atmospheric circulation in east asia was examined the summer blocking occurred mostly in north europe ural region sea of okhotsk ok and northeastern pacific the summer blocking was the major mode in these four regions according to principal component analysis using 500 hpa geopotential heights among the four blocking regions ok blocking frequencies ok bfs showed negative and positive correlations with summer temperature and precipitation of northeast asia centered around the east sea sea of japan respectively in particular the ok bf had a statistically significant correlation coefficient of 0 54 with summer temperatures in the korean peninsula this indicates that the summer temperature and precipitation in this region were closely related to the ok blocking according to the composite analysis for the years of higher than average bf positive bf years the ok high became stronger and expanded while the north pacific high was weakened over the korean peninsula and japan and an anomalously deep trough was developed in the upper layer 200 hpa as the cool ok high expanded the temperature decreased over northeast asia centered around the east sea sea of japan and the lower level 850 hpa air converged cyclonically resulting in the increased precipitation which induced the divergence in the upper layer and thereby strengthened the jet stream thus the boreal summer ok blocking systematically influencing the area as the most dominant mode

the planetary and synoptic scale interactions in a southeast pacific blocking episode using pv diagnostics abstract the synoptic and planetary scale forcing in two blocking anticyclones occurring over the southeast pacific ocean was examined using potential vorticity diagnostics while many studies have examined the dynamic and thermodynamic forcing associated with blocking events in the northern hemisphere nh very few studies have examined blocking in the southern hemisphere sh climatological analysis suggests sh blocking events in the pacific region have similar characteristics to their nh counterparts however the occurrence of blocking is rare elsewhere in the sh and these events are relatively short lived some studies of nh blocking dynamics have also shown that the extent to which the planetary and synoptic scale and planetary synoptic scale interaction forcing that contribute to the genesis and maintenance of pacific and atlantic region events can be different thus a study of the relevant atmospheric dynamics associated with blocking events in the sh was carried out in order to determine wh

morphology and distribution of fossil soils in the permo pennsylvanian wichita and bowie groups north central texas usa implications for western equatorial pangean palaeoclimate during icehouse greenhouse transition analysis of stacked permo pennsylvanian palaeosols from north central texas documents the influence of palaeolandscape position on pedogenesis in aggradational depositional settings palaeosols of the eastern shelf of the midland basin exhibit stratigraphic trends in the distribution of soil horizons structure rooting density clay mineralogy and colour that record long term changes in soil forming conditions driven by both local processes and regional climate palaeosols similar to modern histosols ultisols vertisols inceptisols and entisols all bearing morphological mineralogical and chemical characteristics consistent with a tropical humid climate represent the late pennsylvanian suite of palaeosol orders palaeosols similar to modern alfisols vertisols inceptisols aridisols and entisols preserve characteristics indicative of a drier and seasonal tropical climate throughout the lower permian strata the changes in palaeosol morphology are interpreted as being a result of an overall climatic trend from relatively humid and tropical moist conditions characterized by high rainfall in the late pennsylvanian to progressively drier semi arid to arid tropical climate characterized by seasonal rainfall in early permian time based on known late palaeozoic palaeogeography and current hypotheses for atmospheric circulation over western equatorial pangea the pennsylvanian palaeosols in this study may be recording a climate that is the result of an orographic control over regionalscale atmospheric circulation the trend towards a drier climate interpreted from the permian palaeosols may be recording the breakdown of this preexisting orographic effect and the onset of a monsoonal atmospheric circulation system over this region

the interaction between two separate propagations of rossby waves abstract this study deals with two teleconnection patterns and the subsequent wave train propagations during an east asian summer diagnostic results are as follows 1 a stationary wave ray with zonal wavenumber 5 approximates the arc path linking the correlation centers originating from the caspian sea via lake baikal to the sea off the southeast coast of japan i e the okj arc path as a focus area in a pentad correlation map between 500 hpa geopotential height z500 and outgoing longwave radiation olr at 30 n 150 e in june 1979 98 ray tracing shows that it took 8 10 days for this stationary wave to propagate from an initial position around the caspian sea to the focus area which roughly coincides with the observed case in july 1998 2 a wave train pattern p ja observed in the boreal summer propagated along the arc line in the same way as the normal poleward rossby wave train originating from the philippines across the north pacific p j but with a phase shift northeastward of about 90 3

interannual and interdecadal variations of the east asian summer monsoon and tropical pacific ssts part i roles of the subtropical ridge the interannual relationship between the east asian summer monsoon and the tropical pacific ssts is studied using rainfall data in the yangtze river valley and the ncep reanalysis for 1951 96 the datasets are also partitioned into two periods 1951 77 and 1978 96 to study the interdecadal variations of this relationship a wet summer monsoon is preceded by a warm equatorial eastern pacific in the previous winter and followed by a cold equatorial eastern pacific in the following fall this relationship involves primarily the rainfall during the pre mei yu mei yu season may june but not the post mei yu season july august in a wet monsoon year the western north pacific subtropical ridge is stronger as a result of positive feedback that involves the anomalous hadley and walker circulations an atmospheric rossby wave response to the western pacific complementary cooling and the evaporation wind feedback this ridge extends farther to the west from the previous winter to the following fall resulting in an 850 hpa anomalous anticyclone near the southeast coast of china this anticyclone 1 blocks the pre mei yu and mei yu fronts from moving southward thereby extending the time that the fronts produce stationary rainfall 2 enhances the pressure gradient to its northwest resulting in a more intense front and 3 induces anomalous warming of the south china sea surface through increased downwelling which leads to a higher moisture supply to the rain area a positive feedback from the strong monsoon rainfall also appears to occur leading to an intensified anomalous anticyclone near the monsoon region this sst subtropical ridge monsoon rainfall relationship is observed in both the interannual timescale within each interdecadal period and in the interdecadal scale the sst anomalies sstas change sign in northern spring and resemble a tropospheric biennial oscillation tbo pattern during the first interdecadal period 1951 77 in the second interdecadal period 1978 96 the sign change occurs in northern fall and the tbo pattern in the equatorial eastern pacific sst is replaced by longer timescales this interdecadal variation of the monsoon sst relationship results from the interdecadal change of the background state of the coupled ocean atmosphere system this difference gives rise to the different degrees of importance of the feedback from the anomalous circulations near the monsoon region to the equatorial eastern pacific in a wet monsoon year the anomalous easterly winds south of the monsoon enhanced anomalous anticyclone start to propagate slowly eastward toward the eastern pacific in may and june apparently as a result of an atmosphere ocean coupled wave motion these anomalous easterlies carry with them a cooling effect on the ocean surface in 1951 77 this effect is insignificant as the equatorial eastern pacific sstas already change from warm to cold in northern spring probably as a result of negative feedback processes discussed in enso mechanisms in 1978 96 the equatorial eastern pacific has a warmer mean sst a stronger positive feedback between ssta and the walker circulation during a warm phase tends to keep the ssta warm until northern fall when the eastward propagating anomalous easterly winds reach the eastern pacific and reverse the ssta

authigenic gold formation in the cyanidation tailings of gold arsenopyrite quartz ore of komsomolsk deposit kuznetski alatau russia in this study we assess the link between morphologies and composition of gold grains and supergene processes of au migration and redeposition by aqueous solutions in the aggressive environment of cyanidation tailings high concentrations of both dissolved 10 g l and solid 0 97 ppm native gold in the upper horizons of the komsomolsk tailings profile formed as the result of the long term oxidation of the cyanidation waste these horizons stand out due to contrasting changes in ph eh and the concentration of the elements in solutions from 0 8 10 4 to 72 g l iron from 1 5 10 5 to 30 g l arsenic and from 0 to 37 g l aluminum one of the main findings of this study is that the au and ag contained in tailings as impurities in the residual sulfide minerals are almost completely redeposited in the top few centimeters of the cross section gold dissolves into pore solution in thiosulfate complexes in the reducing environment of the lower part of tailings and mainly in hydroxide complexes in the acidic environment of the upper horizons native gold is found only in the upper few centimeters and presents as irregular grains and crystals of an au ag alloy and as microcrystalline and flat growths of pure au the surface morphologies of gold grains are the result of its supergene dissolution redeposition and crystallization in tailings

strain variations across the proterozoic penokean orogen usa and canada abstract strata in the huron 2 5 2 0 ga and animikie 2 2 1 85 ga basins were deposited on the southern margin of the archean superior province these rocks were deformed during the penokean orogeny 1850 ma followed by subsequent accretionary orogens to the south at 1750 ma yavapai and 1630 ma mazatzal strain patterns are unique to each orogenic belt with no far field effect archean wawa terrane rocks in the penokean foreland preserve deformation associated with archean accretion with no younger penokean yavapai or mazatzal strain overprint the penokean orogeny deformed huron animikie basin sediments into a north vergent fold and thrust belt with no yavapai or mazatzal strain overprint yavapai orogen strains sw ne margin parallel shortening are unique when compared to the younger mazatzal shortening n20 w shortening with no strain overprint penokean deformation is characterized by shortening from the south including uplifted archean gneisses and a northerly thin skinned fold and thrust belt with north vergent nappes and a gently dipping foreland our study of finite and calcite twinning strains n 60 along 1500 km and across 200 km the penokean belt indicate that this orogeny was collisional as layer parallel shortening axes are parallel across the belt or parallel to the tectonic transport direction n s penokean nappe burial near the margin resulted in vertical shortening strain overprints some of which are layer normal the sudbury impact layer 1850 ma is found across the animikie basin and provides a widespread deformation marker with many local unique strain observations we also report new geochronology u pb zircon and apatite for the gneiss mafic dike rocks at wissota chippewa falls wi and arbutus black river falls wi dams respectively which bears on penokean yavapai deformation in the archean marshfield terrane which was accreted during the penokean orogen pseudotachylite formation was common in the superior province archean basement rocks especially along terrane boundaries reactivated by contemporaneous penokean trans hudson cape smith and new quebec deformation in the hinterland south the younger yavapai orogen 1750 ma n 8 deformation is preserved as margin parallel horizontal shortening sw ne in yavapai crust and up to 200 km to the north in the penokean thrust belt as a strain and barrovian metamorphic overprint mazatzal deformation 1630 ma n 16 is preserved in quartzites on yavapai and penokean crust with layer parallel and layer normal shortening strains oriented n20 w

a new microsaur tetrapoda lepospondyli from the lower permian of richards spur fort sill oklahoma bolterpeton carrolli n gen n sp is described from the lower permian fissure fill deposits of richards spur oklahoma bolterpeton is united with the gymnarthrid microsaur cardiocephalus by having teeth compressed labiolingually a narrow anterior process of the prearticular penetrating the splenial and the arrangement of the contacts among the splenial prearticular and coronoids it is united with both cardiocephalus and euryodus by the size and distribution of the coronoid teeth and the presence of longitudinal striations of enamel on the lingual tooth surface unlike those two genera bolterpeton has peg like teeth but it remains unknown whether this represents the primitive condition or a reversal of the massive conical teeth typical of gymnarthrids bolterpeton possesses a flat lamina that runs along the lingual surface of the tooth margin where two laminae meet at the point of the tooth a labiolingual ridge is formed which is most pronounced at smaller sizes reexamination of cardiocephalus shows it to have the same morphology on its incisors previous authors have defined teeth bearing this ridge as weakly bicuspid if this ridge were homologous with the strongly bicuspid condition of lissamphibians bolterpeton would provide the first example of this tooth morphology in lepospondyls and would strengthen recent hypotheses suggesting lepospondyls gave rise to some if not all modern amphibians resume bolterpeton carrolli nouveau genre et nouvelle espece est decrit a partir des depots de remplissage de fissure permiens precoces de richards spur en oklahoma bolterpeton est relie au microsaure gymnarthride cardiocephalus du fait qu il a les dents comprimees labiolingualement un processus prearticulaire anterieur mince penetrant le splenial et selon l arrangement des contacts entre le splenial le prearticulaire et les coronoides il est relie avec cardiocephalus et euryodus par la taille et la distribution des dents coronoides et la presence de stries longitudinales de l email sur la face linguale des dents contrairement a ces deux genres bolterpeton possede des dents en forme de piquet mais il demeure indetermine si cela represente une condition primaire ou un renversement des dents coniques massives typique des gymnarthrides bolterpeton possede une lamine plate qui parcourt la surface linguale de la marge des dents a l endroit ou deux lamines se rencontrent a la pointe des dents une crete labiolinguale est formee laquelle est plus prononcee pour les tailles plus petites un nouvel examen de cardiocephalus montre qu il possede la meme morphologie sur ses incisives des auteurs precedents ont defini les dents possedant cette crete comme faiblement bicuspides si cette crete etait homologuee a la condition fortement bicuspide des lissamphibiens bolterpeton deviendrait le premier exemple de cette morphologie dentaire chez les lepospondyles et viendrait renforcer les hypotheses recentes qui suggerent que les lepospondyles ont donne naissance a certains sinon a tous les amphibiens modernes traduit par la redaction anderson and reisz 505 dedication

captorhinus magnus a new captorhinid amniota eureptilia from the lower permian of oklahoma with new evidence on the homology of the astragalus the new species of single tooth rowed captorhinid reptile captorhinus magnus n sp from the lower permian fissure fillings at richards spur oklahoma differs from captorhinus aguti in body size and dental and femoral morphology linear measurements of fully mature c magnus elements range in size from 1 5 to 2 3 times as great as those of c aguti and the proximal articular surface of the femur which is convex in c aguti is concave throughout ontogeny c magnus possesses ogival cheek teeth aligned in a single row indicating that ogival dentition can no longer be considered unique to c aguti a phylogenetic analysis of captorhinid interrelationships indicates that c aguti and c magnus form a clade that possesses a sister group relationship with captorhinus laticeps incompletely ossified astragali referred to c magnus provide unequivocal evidence that the astragalus of captorhinus formed through the fusion of three originally separate ossifications the tibiale intermedium and proximal centrale rather than from a single ossification center at the richards spur locality c magnus is the most abundant captorhinus species produced from the deeper stratigraphically lower sediments of the quarry it is rare however in the uppermost presumably younger deposits where c aguti represents the most numerous richards spur captorhinid resume une nouvelle espece de reptile captorhinide a rangee de dents simple captorhinus magnus n sp provenant de remplissage de fissures au permien inferieur a richards spur en oklahoma differe de captorhinus aguti par la dimension de son corps et la morphologie du femur les mesures lineaires d un c magnus a pleine maturite vont de 1 5 a 2 3 fois celles du c aguti et la surface articulaire proximale du femur laquelle est convexe chez c aguti est concave a travers l entiere ontogenese c magnus possede des dents jugales ogivales alignees en rangee simple indiquant que la dentition ogivale ne peut plus etre consideree unique a c aguti une analyse phylogenetique des interrelations de captorhinides indique que c aguti et c magnus forment un clade qui possede une relation de parente de groupe avec captorhinus laticeps des astragales non completement ossifies attribues a c magnus fournissent des evidences non equivoques que l astragale de captorhinus s est forme par la fusion de trois ossifications originalement separees le tibial l intermediaire et le naviculaire proximal plutot qu a partir d un centre unique d ossification a la localite de richard spurs c magnus est l espece de captorhinus la plus abondante provenant de sediments plus profonds stratigraphiquement inferieurs de la carriere cette espece est toutefois rare dans les depots superieurs probablement plus jeunes ou c aguti represente le captorhinide le plus abondant de richards spur

pacific east asian teleconnection how does enso affect east asian climate observational evidence is presented to show a teleconnection between the central pacific and east asia during the extreme phases of enso cycles this pacific east asian teleconnection is confined to the lower troposphere the key system that bridges the warm cold events in the eastern pacific and the weak strong east asian winter monsoons is an anomalous lower tropospheric anticyclone cyclone located in the western north pacific the western north pacific wind anomalies develop rapidly in late fall of the year when a strong warm or cold event matures the anomalies persist until the following spring or early summer causing anomalously wet dry conditions along the east asian polar front stretching from southern china northeastward to the east of japan kuroshio extension using atmospheric general circulation and intermediate models the authors show that the anomalous philippine sea anticyclone results from a rossby wave response to suppressed convective heating which is induced by both the in situ ocean surface cooling and the subsidence forced remotely by the central pacific warming the development of the anticyclone is nearly concurrent with the enhancement of the local sea surface cooling both the anticyclone and the cooling region propagate slowly eastward the development and persistence of the teleconnection is primarily attributed to a positive thermodynamic feedback between the anticyclone and the sea surface cooling in the presence of mean northeasterly trades the rapid establishment of the philippine sea wind and sst anomalies implies the occurrence of extratropical tropical interactions through cold surge induced exchanges of surface buoyancy flux the central pacific warming plays an essential role in the development of the western pacific cooling and the wind anomalies by setting up a favorable environment for the anticyclone sst interaction and midlatitude tropical interaction in the western north pacific

shifts in late paleozoic atmospheric circulation over western equatorial pangea insights from pedogenic mineral δ18o compositions the d 18 o values of pedogenic calcites phyllosilicates and iron oxyhydr oxides from fossil soils throughout the southwestern united states show systematic paleolatitudinal and temporal trends that indicate a significant change in soil moisture conditions and atmospheric circulation patterns over southwestern euramerica throughout latest pennsylvanian and early permian time a progressive depletion of as much as 6 in mineral 18 o values with increasing distance northward to 108 of the paleoequator indicates a weakening or disruption of zonal easterly flow over the study area by latest pennsylvanian time furthermore elevated d 18 o values suggest a proximal source of paleoprecipitation over the study area perhaps due to initiation of reversed equatorial flow over tropical southwestern euramerica coupling of the geographic and temporal trends defined by pedogenic mineral d 18 o values with those defined by climatically sensitive paleosol pedotypes in the study area along with overall elevated mineral d 18 o values provides some of the strongest evidence that northern hemisphere monsoonal circulation was well established over pangea by early permian time

geochemical and mineralogical aspects of sulfide mine tailings abstract tailings generated during processing of sulfide ores represent a substantial risk to water resources the oxidation of sulfide minerals within tailings deposits can generate low quality water containing elevated concentrations of so 4 fe and associated metal loid s acid generated during the oxidation of pyrite fes 2 pyrrhotite fe 1 x s and other sulfide minerals is neutralized to varying degrees by the dissolution of carbonate oxy hydroxide and silicate minerals the extent of acid neutralization and therefore pore water ph is a principal control on the mobility of sulfide oxidation products within tailings deposits metals including fe iii cu zn and ni often occur at high concentrations and exhibit greater mobility at low ph characteristic of acid mine drainage amd in contrast hydr oxyanion forming elements including as sb se and mo commonly exhibit greater mobility at circumneutral ph associated with neutral mine drainage nmd these differences in mobility largely result from the ph dependence of mineral precipitation dissolution and sorption desorption reactions cemented layers of secondary oxy hydroxide and hydroxy sulfate minerals referred to as hardpans may promote attenuation of sulfide mineral oxidation products within and below the oxidation zone hardpans may also limit oxygen ingress and pore water migration within sulfide tailings deposits reduction oxidation redox processes are another important control on metal loid mobility within sulfide tailings deposits reductive dissolution or transformation of secondary oxy hydroxide phases can enhance fe mn and as mobility within sulfide tailings production of h 2 s via microbial sulfate reduction may promote attenuation of sulfide oxidation products including fe zn ni and tl via metal sulfide precipitation understanding the dynamics of these interrelated geochemical and mineralogical processes is critical for anticipating and managing water quality associated with sulfide mine tailings

arsenic in iron cements developed within tailings of a former metalliferous mine enguiales aveyron france abstract arsenopyrite rich waste from a former metalliferous mine were spread out over the sloping side of a deep valley after processing over the past 30 a they have been subjected to rainfall and acid water originating from the abandoned mine galleries this intensive leaching has led to the formation of thin layers of as fe crusts on the tailings surface acting as a cement x ray diffraction and sem coupled with eds determined that jarosite was present in all mineral samples and could contain a small amount of as 5 7 wt in addition empa and raman microspectroscopy characterised the presence of amorphous as v fe hydrates as well as rare arsenate minerals e g scorodite raman microspectroscopy in particular identified a preponderance of goethite or hematite within the mineral framework of the tailings materials that is likely to sorb recalcitrant as species the characterisation of the components of the tailings enable the identification of their evolution shows the progressive decrease of their as content and emphasises the consequences of the temporary trapping of as in the very acidic and oxidising conditions prevailing in such environments resinous amorphous material was identified as the richest in as with as 17 1 wt this material evolved toward more crystallised phases e g goethite jarosite which contained less as 3 2 wt

on the three dimensional propagation of stationary waves abstract a locally applicable nonzonally averaged conservation relation is derived for quasi geostrophic stationary waves on a zonal flow a generalization of the eliassen palm relation the flux which appears in this relation constitutes it is argued a useful diagnostic of the three dimensional propagation of stationary wave activity this is illustrated by application to a simple theoretical model of a forced rossby wave train and to a northern hemisphere winter climatology results of the latter procedure suggest that the major forcing of the stationary wave field derives from the orographic effects of the tibetan plateau and from nonorographic effects diabatic heating and or interaction with transient eddies in the western north atlantic and north pacific oceans and siberia no evidence is found in the data for wave trains of tropical origin forcing by the orographic effects of the rocky mountains seems to be of secondary importance

the differences between early and midwinter atmospheric responses to sea surface temperature anomalies in the northwest atlantic abstract using an atmospheric global spectral model it is shown that the winter atmosphere in the midlatitudes is capable of reacting to prescribed sea surface temperature sst anomalies in the northwest atlantic with two very different responses the nature of the response is determined by the climatological conditions of the winter regime experiments are performed using either the perpetual november or january conditions with or without the prescribed sst anomalies warm sst anomalies in november result in a highly significant anomalous ridge downstream over the atlantic with a nearly equivalent barotropic structure in january the response is a statistically less significant trough the presence of the sst anomalies also causes a northward southward shift of the atlantic storm track in the november january cases a diagnostic analysis of the anomalous heat advection in the simulations reveals that in the january cases the surface heating is offset primarily by the strong horizontal cold advect

the climatology of blocking anticyclones for the northern and southern hemispheres block intensity as a diagnostic abstract a 30 yr climatology of blocking events was compiled by stratifying the data into seasonal and three regional categories for both the northern and southern hemispheres using the ncep ncar reanalyses several characteristics of blocking anticyclones were included in the study and these were frequency of occurrence preferred formation regions duration blocking days and intensity the block intensity bi calculation was modified successfully from a previous study in order to automate the procedure for use with large datasets and it is applied for the first time to derive a long term observational record of this quantity this modification also makes bi suitable for use as a diagnostic tool blocking events in the northern southern hemisphere were the most persistent and strongest during the cold season and over the atlantic pacific region as found using bi to measure intensity the characteristics of blocking events derived in this study were compared to previous long term climatological s

rare earth elements as a tool for studying the formation of cemented layers in an area affected by acid mine drainage abstract in a profile with two cemented layers sampled in an area affected by acid mine drainage both have rare earth element ree signatures with positive ce anomalies in the post archean australian shale normalised patterns both cemented layers have higher contents of environmentally relevant metals cd co cu fe mn u and zn than the over and underlying unconsolidated quaternary sediments and are depleted of al ca k and mg the cemented layers are enriched in middle and heavy ree but only the bulk pattern of the lower cemented layer reveals a positive ce anomaly for the upper cemented layer this positive ce anomaly was only determined by spatially resolved laser ablation inductively coupled plasma mass spectrometry la icp ms studies only for segments with a high abundance of mn occurring as mn phases as proven by energy dispersive x ray spectroscopy the mn phases are formed secondarily to the ferric cement and are especially enriched in ce and co the ce anomaly of the lower cemented layer most probably is inherited from groundwater to the ferric cement whereas the ce anomaly of the upper cemented layer is the result of preferential scavenging of ce onto the mn phases compared to other ree

an extratropical air sea interaction over the north pacific in association with a preceding el nino episode in early summer abstract using data for the month of june from 1951 through 2000 this study examined the air sea interactions over the north pacific after el nino matured during the preceding fall season the principal findings of this work are the following 1 a coherent region near the international date line idl in the extratropical north pacific revealed an area of significant negative correlations sncs between the preceding november sea surface temperature sst in the nino 3 region and the june sst in the north pacific also two indexes of the june okhotsk high show a significant positive correlation with the november sst in the nino 3 region during the 1963 2000 period 2 the strong southeastward wave flux from the upstream area of the okhotsk sea over much of the north pacific in the midlatitudes is associated with a strong preceding el nino event the development of the okhotsk high and a negative 500 hpa geopotential height sst anomaly around the coherent region the stationary wave propagation plays a

different types of cold vortex circulations over northeast china and their weather impacts abstracta deep and cold vortex circulation often occurs over northeast china known as the northeast china cold vortex nccv the phenomenon is most active from may to mid june and can lead to extremely cold local temperatures this study used rotated principle component analysis to categorize nccv events into four types which were characterized by ridges or blocks over the following regions lake baikal bkl the yenisei river valley yns the ural mountains ur and the yakutsk okhotsk region yo on the intraseasonal time scale it was found that bkl and yns type nccvs formed when the wave train height anomalies originating from the north atlantic and europe propagated to east asia in contrast yo and ur type nccvs formed in conjunction with the development of a meridional dipole pattern over northeast asia the existence of a blocking type circulation over the yakutsk okhotsk region favored maintenance of the nccv circulation for the long lived more than 5 days nccv events of the four type

evolution and dynamics of summertime blocking over the far east and the associated surface okhotsk high time evolution and dynamics of an upper level blocking ridge over the far east and the associated surface high over the sea of okhotsk that give rise to abnormal summertime coolness over eastern japan are investigated through a composite analysis applied to distinct surface high events the formation mechanism and vertical structure of the blocking differ fundamentally between may and july attributable to seasonal changes in the jet structure storm track activity over the far east and the land sea thermal contrast within the okhotsk region in may forcing from migratory eddies is strong enough for precursory anticyclonic anomalies retrograding slowly over the north pacific to develop into a blocking ridge the ridge remains equivalent barotropic under the weak land sea thermal contrast in the okhotsk region in contrast the eddy forcing is no longer the primary factor for the blocking formation in july in the presence of the weakened and split westerlies rather the propagation of a stationary rossby wave packet that has emanated from precursory anticyclonic anomalies over northern europe stagnates over the far east and the subsequent local breaking of the packet leads to the blocking formation in a particular case in july 1993 a wave packet involved in blocking formation could be traced back as far upstream as the east coast of north america over the two previous weeks acting on the strong thermal contrast in july between the cool sea surface and a warm land mass to the west the anomalous surface easterlies induced by the blocking ridge can build up a cold surface anticyclone through cold advection rendering the blocking anomalies distinctly baroclinic copyright 2004 royal meteorological society

speleothem climate records from deep time exploring the potential with an example from the permian speleothems are well proven archives of terrestrial climate variation recording mean temperature rainfall and surface vegetation data at subannual to millennial resolution they also form within the generally stable environment of caves and thus may remain remarkably well preserved for many millions of years and most important can be dated radiometrically to provide robust chronologies that do not rely on orbital tuning ice flow modeling or estimates of sediment deposition rates the recent adaptation of the u pb dating technique to speleothems has greatly extended their potential as paleoclimate recorders back into the more distant geological past well beyond the 500 k y limit previously imposed by u series techniques but the opportunities presented by these new methods have yet to be fully explored as an extreme example here we report on samples recovered from permian cave fills the oldest radiometrically dated speleothems so far documented using state of the art analytical techniques it is possible to determine not only their age and state of preservation but also to extract apparently nearly pristine climate proxy data armed with these methods it now seems reasonable to apply the lessons learned from more recent speleothems to ancient materials wherever they can be found and of whatever age to generate snapshots of paleoclimate that can be used to greatly refine the records preserved within the sediments and fossils of the time

the effect of enso on tibetan plateau snow depth a stationary wave teleconnection mechanism and implications for the south asian monsoons abstract an atmospheric stationary wave teleconnection mechanism is proposed to explain how enso may affect the tibetan plateau snow depth and thereby the south asian monsoons using statistical analysis the short available record of satellite estimates of snow depth and ray tracing it is shown that wintertime enso conditions in the central pacific may produce stationary barotropic rossby waves in the troposphere with a northeastward group velocity these waves reflect off the north american jet turning equatorward and enter the north african asian jet over the eastern atlantic ocean once there the waves move with the jet across north africa south asia the himalayas and china anomalous increases in upper tropospheric potential vorticity and increased wintertime snowfall over the tibetan plateau are speculated to be associated with these rossby waves the increased snowfall produces a larger tibetan plateau snowpack which persists through the spring and summer and weakens the intensity of the

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

the remote effect of the tibetan plateau on downstream flow in early summer 1 by using numerical experiments and observational data this study examined the uplifting and thermal effects of the tibetan plateau tp on downstream airflow in early summer our principal finding is that the uplifting effect of the tp in an atmospheric general climate model agcm including air made warmer than its surroundings climatologically by the huge topography results mainly in a local response in the atmosphere i e a large ridge north of the tp in the troposphere in june there was no rossby wave response to the uplifting effect however simulations and statistical analyses strongly suggested that the anomalous tp atmospheric heating associated with global climate warming tends to excite a rossby wave originating from the tp via lake baikal and continuing to move through the okhotsk sea to downstream areas the appearance of the rossby wave coincides with the positive phase of the eastern part of a normal stationary wave originating in the caspian sea traveling via the okhotsk sea to the sea area east of japan that often occurs in june thus the tp atmospheric heating acts as an additional wave source in relaying and enhancing the eastern part of the normal wave propagation its path usually lies beyond 40 n latitude which is where the westerly jet stream takes over the role of waveguide

influence of hardpan layers on arsenic mobility in historical gold mine tailings abstract hardpans or cemented layers form by precipitation and cementation of secondary minerals in mine tailings and may act as both physical and chemical barriers precipitation of secondary minerals during weathering of tailings can sequester metal loid s thereby limiting their release to the environment at montague gold mines in nova scotia tailings are partially cemented by the fe arsenate mineral scorodite feaso4 2h2o previous studies have shown that the formation of scorodite can effectively limit aqueous as concentrations due to its relatively low solubility

u pb zircon and titanite systematics of the fish canyon tuff an assessment of high precision u pb geochronology and its application to young volcanic rocks a large data set of single and multi grain zircon and titanite analyses from a sample of the oligocene fish canyon tuff fct a voluminous ash flow from the san juan mountains of colorado and widely used 40ar 39ar geochronological standard has been used to evaluate the influence of various sources of analytical and geological uncertainty on the calculated age of this tuff by the isotope dilution u pb zircon method twenty three single zircon grains and seven small multi grain fractions of the fct yield an inverse variance weighted mean 206pb 238u date of 28 402 0 023 ma 2 mswd 0 93 and a slightly older weighted mean 207pb 235u date of 28 529 0 030 ma mswd 0 74 which are insensitive to common pb corrections initial 230th disequilibria calculated from a newly measured th u 2 2 for fct pumice shards indicate th deficiency for these zircons its correction brings the weighted mean 206pb 238u date to 28 478 0 024 mswd 0 97 minimizing the discordance of the fct zircon analyses these calculations culminate in concordia ages ludwig 1998 for the crystallization of the fct zircons of 28 476 0 029 ma mswd 1 50 without propagating decay constant errors or 28 498 0 035 ma mswd 1 03 with propagated decay constant errors these results are in close agreement with a previous single grain 206pb 238u zircon date of 28 41 0 05 ma for the fct oberli et al 1990 however they do not corroborate the discordia lower intercept date of 27 52 0 09 put forth by lanphere and baadsgard 2001 the 28 476 0 064 ma concordia age for fct zircons including systematic decay constant errors and uncertainty in pb u tracer calibration is substantially older than all published 40ar 39ar sanidine ages which range from 27 5 to 28 05 ma lanphere and baadsgaard 1997 renne et al 1998 a lengthy period 400 k y of zircon residence in the magma chamber before eruption is commonly called upon to explain the age discrepancy however fct titanite which may remain open to pb diffusive exchange until quenching upon eruption yield a minimum 230th disequilibrium corrected weighted mean 206pb 238u age of 28 395 0 049 ma 0 078 with tracer uncertainty weakening residence time arguments and supporting recent calls for re evaluation of the 40k decay constant and the accepted ages for commonly used 40ar 39ar mineral standards the fct zircon concordia age also provides an empirical constraint on the decay constants of the u isotopes indicating the relative accuracy of the currently accepted decay constants to within the original counting statistic errors of jaffey et al 1971

improved extended reconstruction of sst 1854 1997 abstract an improved sst reconstruction for the 1854 1997 period is developed compared to the version 1 analysis in the western tropical pacific the tropical atlantic and indian oceans more variance is resolved in the new analysis this improved analysis also uses sea ice concentrations to improve the high latitude sst analysis and a modified historical bias correction for the 1939 41 period in addition the new analysis includes an improved error estimate analysis uncertainty is largest in the nineteenth century and during the two world wars due to sparse sampling the near global average sst in the new analysis is consistent with the version 1 reconstruction the 95 confidence uncertainty for the near global average is 0 4 c or more in the nineteenth century near 0 2 c for the first half of the twentieth century and 0 1 c or less after 1950

formation and composition of cemented layers in low sulphide mine tailings laver northern sweden cemented layers hardpans are common in carbonate or sulphide rich mine tailings and where pyrrhotite is the predominating fe sulphide laver northern sweden is an abandoned cu mine where the tailings have low pyrrhotite content almost no pyrite and no carbonates two cemented layers at different locations in the laver tailings impoundment were investigated with the aim to determine their effects on metal mobility the cementing agents were mainly jarosite and fe oxyhydroxides in the layer formed where the tailings have a barren surface whereas only fe oxyhydroxides were identified below grass covered tailings surface arsenic was enriched in both layers which also exhibit high concentrations of mo v hg and pb compared to unoxidised tailings sequential extraction indicates that these metals and as were mainly retained with crystalline fe oxides and therefore potentially will be remobilised if the oxic conditions become more reducing for instance as a result of remediation of the tailings impoundment

the unique preservational environment of the early permian cisuralian fossiliferous cave deposits of the richards spur locality oklahoma abstract the richards spur locality oklahoma usa represents an early permian infill in a series of ordovician limestone and dolostone karst fissures it exhibits the most diverse terrestrial palaeozoic community currently known with 40 distinct tetrapod taxa speleothems intimately associated with the site indicate that richards spur is a cave system suggesting a preservational environment that is distinct from those of more typical early permian lowland deltaic fluvial localities fossil material obtained from the caves is often found in disarticulation although articulated material is not uncommon this suggests that there were several factors that affected how animal remains became deposited within the caves many animals that died outside the caves were likely disarticulated on the surface and then washed in during rainfall events resulting in mostly disarticulated remains alternatively animals could be washed in before being disarticulated and some probably fell into the caves resulting in less chance for their remains to become disarticulated supporting evidence for these preservational hypotheses comes in the form of wear caused by attritional processes disarticulated elements can exhibit high levels of wear likely due to water transport that would carry them into the caves from the surface as well as reworking within the caves the partially and completely articulated remains are normally unworn presumably due to a lesser degree of transport and reworking x ray diffraction and stable isotope analysis of cave infill further supports the interpretations made from fossil material the results of this study provide a much improved understanding of the preservational environment at richards spur and will be useful in integrating information from this unique upland locality with that from the more extensively studied lowland localities of the early permian

u pb systematics of the mcclure mountain syenite thermochronological constraints on the age of the 40 ar 39 ar standard mmhb recent advances in u pb geochronology allow unprecedented levels of precision in the determination of geological ages however increased precision has also illuminated the importance of understanding subtle sources of open system behavior such as pb loss inheritance intermediate daughter product disequilibria and the accuracy of the model assumptions for initial pb deconvolution of these effects allows a much richer understanding of the power and limitations of u pb geochronology and thermochronology in this study we report high precision id tims u pb data from zircon baddelleyite titanite and apatite from the mcclure mountain syenite from which the 40 ar 39 ar hornblende standard mmhb is derived we find that excess 206 pb in zircon due to inclusions of high th minerals and ele vated th u in titanite and apatite jeopardize the utility of the 238 u 206 pb system in this rock strongly air abraded zircons give dates that are younger than chemical abraded zircons which yield a statistically robust 207 pb 235 u date of 523 98 0 12 ma that is interpreted as the crystallization age we explore the best method of pbc correction in titanite and apatite by analyzing the u pb isotopes of k feldspar and using 2 d and 3 d regression methods the latter of which yields the best results in each case however the calcu lated compositions of pbc for titanite apatite and k feldspar are different implying that using a single pbc correction for multiple u pb thermochronometers may be inaccurate the u pb thermochronological results are used to predict a closure time for ar in hornblende of 522 98 1 00 ma widely cited k ar and 40 ar 39 ar dates overlap with the u pb date and relatively large errors make it impossible to verify whether u pb dates are systematically 1 older than k ar and 40 ar 39 ar dates

sea surface temperature anomalies planetary waves and air sea feedback in the middle latitudes the mechanisms that contribute to the generation and damping of large scale mid latitude sea surface temperature sst anomalies are discussed the sst anomalies reflect primarily the response of the upper ocean to the changes in air sea fluxes that are associated with daily weather fluctuations heat flux forcing is dominant in the lower middle latitudes while wind driven entrainment may be most effective in the high latitudes advection by anomalous ekman current is generally less important and ekman pumping is negligible the sst anomalies decay in part because of entrainment effects associated with mixed layer deepening and oceanic mixing and in part because of heat exchanges with the atmosphere the three approaches commonly used to model the evolution of sst anomalies are reviewed case studies based on monthly or seasonal anomaly maps of the large scale sst and atmospheric anomalies numerical simulations with one dimensional mixed layer models and stochastic forcing models we stress the similarities in the different approaches and discuss their main advantages and limitations the response of the atmosphere to mid latitude sst anomalies is considered first we discuss the poorly known relationship between sst anomalies and diabatic heating using a crude assumption for the air sea coupling we consider a two layer quasi geostrophic channel model and discuss the stationary wave response to sst anomaly forcing and the resulting air sea feedback it is found that the back interaction of the sst anomalies onto the atmosphere causes a weak sst anomaly damping at large scales and a strong one at small scales the air sea coupling should also act as an eastward propagator for the sst anomalies the response of more realistic linear wave models to prescribed diabatic heating is then reviewed and it is suggested that realistic mid latitude sst anomalies have a weak influence on the atmospheric circulation corresponding to changes in the geopotential height of 10 30 m at most this order of magnitude is consistent with the results of general circulation model experiments and with the limited climate predictability associated with mid latitude sst anomalies

δ13c values of carbonate nodules across the permian triassic boundary in the karoo supergroup south africa reflect a stinking sulfurous swamp not atmospheric co2 abstract paleosol macromorphology petrography and stable isotope geochemistry of carbonate nodules from permo triassic p t boundary strata of the central karoo basin south africa are presented in order to evaluate their utility as geochemical archives of permian triassic paleoatmospheric chemistry and their potential to provide a terrestrial carbon isotope chemostratigraphy for correlation with contemporaneous global marine 13 c records paleosol morphologies across p t boundary strata of the central karoo basin indicate the region was a poorly drained seasonally to continuously flooded bottomland radiaxial calcite microspar and micrite microtextures are observed in the calcite nodules associated with p t paleosol profiles micritic calcite is typical of soil carbonate that forms in well drained soils characterized by open system gaseous diffusion between the soil and global atmosphere whereas more coarsely crystalline textures and radiaxial calcite are more typical of crystallization in phreatic environments with limited gaseous diffusion between the soil and global atmosphere in this regard only those nodules composed of micritic calcite can be considered as a potentially reliable source of proxy information for paleoatmospheric 13 c values across the p t boundary the 13 c values of all carbonate nodules from two overlapping measured sections near carlton heights south africa range from 24 4 to 1 8 whereas micritic calcite nodule 13 c values range from 7 0 to 21 3 comparison of calcite 13 c values with penecontemporaneous organic matter 13 c values indicate that calcite 13 c values 13 c values rather these more negative carbonate nodule 13 c values likely reflect calcite crystallization under poorly drained swampy conditions characterized by a semi closed chemical system that evolved independently of earth s troposphere therefore previously reported negative carbon isotope shift s measured from carbonate nodules in the karoo basin p t strata do not provide a record of atmospheric 13 c and probably do not provide a viable carbon isotope stratigraphy that can be realistically correlated with global p t marine carbon isotope stratigraphies