geochemical and mineralogical evidence for a coal hosted uranium deposit in the yili basin xinjiang northwestern china abstract the petrological geochemical and mineralogical compositions of the coal hosted jurassic uranium ore deposit in the yili basin of xinjiang province northwestern china were investigated using optical microscopy and field emission scanning electron microscopy in conjunction with an energy dispersive x ray spectrometer as well as x ray powder diffraction x ray fluorescence and inductively coupled plasma mass spectrometry the yili coal is of high volatile c b bituminous rank 0 51 0 59 vitrinite reflectance and has a medium sulfur content 1 32 on average fusinite and semifusinite generally dominate the maceral assemblage which exhibits forms suggesting fire driven formation of those macerals together with forms suggesting degradation of wood followed by burning the yili coals are characterized by high concentrations of u up to 7207 g g se up to 253 g g mo 1248 g g and re up to 34 g g as well as as up to 234 g g and hg up to 3858 ng g relative to the upper continental crust the rare earth elements rees in the coals are characterized by heavy or and medium ree enrichment the minerals in the yili coals are mainly quartz kaolinite illite and illite smectite as well as to a lesser extent k feldspar chlorite pyrite and trace amounts of calcite dolomite amphibole millerite chalcopyrite cattierite siegenite ferroselite krutaite eskebornite pitchblende coffinite silicorhabdophane and zircon the enrichment and modes of occurrence of the trace elements and also of the minerals in the coal are attributed to derivation from a sediment source region of felsic and intermediate petrological composition and to two different later stage solutions a u se mo re rich infiltrational and a hg as rich exfiltrational volcanogenic solution the main elements with high enrichment factors u se as and hg overall exhibit a mixed organic inorganic affinity the uranium minerals pitchblende and coffinite occur as cavity fillings in structured inertinite macerals selenium as and hg in high pyrite samples mainly show a sulfide affinity

origin of lead from green glass of apollo 15426 a search for primitive lunar lead a major obstacle in lunar u pb chronology is the elusiveness of the primary pb isotopic composition and u pb ratio and therefore the pb evolution for the early history of the moon in an attempt to seek the primitive lunar pb isotopic composition green glass from lunar clod 15426 49 was studied for u th pb systematics because it is extremely mg rich and known to be the most primitive among sampled lunar volcanic rocks green glass and yellow impact glass were handpicked washed with water then washed in an acid mixture 0 3 n hbr 0 2 n hf and the washes and residues were analyzed in contrast to the pb from apollo 17 orange glass pb from the surface of the green glass spherules is totally different from that of the spherule interior but is similar to lunar surface lead data for the interior pb yield a 207pb 206pb age of 3 41 ga because of the low pb concentration and high u pb ratio observed for the interior the initial pb was poorly defined nevertheless the data indicate that lunar pb evolved in an environment with 238u 204pb 19 55 which is considerably lower than those for mare basalts around 300 but higher than values for the earth 6 8

noble component organization in apollo 14 breccia 14318 129i and 244pu regolith chronology noble gas petrological and chemical studies made on grain size separates from lunar regolith breccia 14318 demonstrate that the noble gases are organized into two functional components volume correlated and surface correlated as in regolith breccia 14301 volume correlated xenon in 14318 is primarily spallation derived and the surface correlated component contains not only solar wind xenon but also significant amounts of parentless xenon from the fission of now extinct 244pu and the decay of now extinct 229i parentless means the daughter products were incorporated onto grain surfaces following decay of the parent nuclide elsewhere the ratio of 129xe 136xe in the total surface correlated parentless component as identified in grain size analysis is substantially higher than in the least tightly bound parentless component identified in stepwise heating analyses confirming the trend seen in 14301 if the order of release of gases in stepwise heating is related to the order of incorporation in the simplest way first in last out incorporation of these grain surface components was probably time ordered the 129xe 136xe ratio in each identifiable parentless component would then be characteristic of the xenon available for surface adsorption at the particular time of acquisition continuous variations in this ratio further suggest that incorporation of the parentless xenon was closely coupled with production such observations provide the basis for a new chronometer from which we conclude that acquisition of parentless xenon was an ongoing process spanning at least 90 m y beginning no more than 63 34 m y after the formation of primitive meteorites and possibly predating xenon acquisition for the earth

magnesium isotopic composition of the moon abstract the mg isotopic compositions of 47 well characterized lunar samples including mare basalts highland rocks regolith breccias and mare and highland soils were measured to address the behavior of mg isotopes during lunar magmatic differentiation constrain the mg isotopic composition of the moon and evaluate the degree of mg isotopic fractionation between planetary bodies the 26 mg values range from 0 61 0 03 to 0 02 0 06 in 22 mare basalts from 0 34 0 04 to 0 18 0 06 in 3 highland rocks from 0 33 0 05 to 0 14 0 08 in 7 regolith breccias from 0 23 0 05 to 0 14 0 07 in 6 highland soils and from 0 41 0 05 to 0 20 0 09 in 9 mare soils the limited mg isotopic variation among bulk mare and highland soils and regolith breccias indicates negligible mg isotope fractionation by lunar surface processes by contrast the large mg isotopic fractionation between low ti and high ti basalts suggests the source heterogeneity produced during fractional crystallization of the lunar magma ocean with ilmenite having lighter mg isotopic compositions than olivine and pyroxene overall the moon has a weighted average mg isotopic composition 26 mg 0 26 0 16 indistinguishable from the earth 26 mg 0 25 0 07 and chondrites 26 mg 0 28 0 06 suggesting homogeneous mg isotopic distribution in the solar system and the lack of mg isotope fractionation during the moon forming giant impact

soil grain and water chemistry in relation to human selenium responsive diseases in enshi district china selenium deficiency keshan disease and toxicity diseases in humans occur within 20 km of each other in enshi district in china and have been linked to environmental levels of se low concentrations of se are associated with jurassic siltstones and sandstones whereas high concentrations occur in areas underlain by permian carbonaceous strata although these broad relationships between se in the environment and the human population have been established previously not all villages underlain by the carbonaceous strata suffer se toxicity problems and the precise controls on se distribution and availability have not been quantified in the present study soil grain drinking water and human hair samples are examined to determine the controls on se availability in 3 se environments in enshi district five low se and keshan disease villages 5 high se and no toxicity villages and 5 high se and toxicity villages were selected for the study results show that the majority of samples in the low se villages are deficient or marginal in se and that se availability to plants is inhibited by adsorption onto organic matter and fe oxyhydroxides in soil therefore remediation strategies involving the application of se fertiliser direct to the soil may not increase plant se levels as expected in the high se villages localised lithological variations result in considerable ranges in se concentrations in all sample types deficient and excessive levels of se are recorded in samples from the same village selenium bioavailability in the high se toxicity villages is controlled by the total soil se concentration and ph a greater proportion of the se is plant available in villages where the carbonaceous strata are interbedded with limestone villagers should be advised to avoid planting crops in these areas if possible

prolonged post rift magmatism on highly extended crust of divergent continental margins baiyun sag south china sea three dimensional 3d seismic borehole and geochemical data reveal a prolonged phase of post rift magmatism on highly extended crust of the baiyun sag south china sea two volcanic complexes are identified and described in the context of continental rifting and diachronous continental breakup of the south china sea biostratigraphic data from exploration wells by7 1 and by2 complemented by k ar datings from core samples confirm that magmatic activity in the baiyun sag occurred in two main stages 1 a first episode at the base of the miocene 23 8 ma and 2 a second episode occurring at the end of the early miocene 17 6 ma the relative location of volcanic complexes in the baiyun sag and their stratigraphic position reveals prolonged magmatism inboard of the ocean continent transition zone during continental breakup we suggest that magmatism in the baiyun sag reflects progressive continental breakup in the south china sea with the last volcanic episode marking the end of a breakup sequence representing the early post rift tectonic events associated with the continental breakup process seismic and borehole data from this breakup sequence records diachronous magma emplacement and complex changes in depositional environments during continental breakup c 2016 the authors published by elsevier b v

environmental signal propagation in sedimentary systems across timescales abstract earth surface processes operate across erosionally dominated landscapes and deliver sediment to depositional systems that can be preserved over a range of timescales the geomorphic and stratigraphic products of this source to sink sediment transfer record signals of external environmental forcings as well as internal or autogenic dynamics of the sedimentary system here we evaluate environmental signal propagation across sediment routing systems with emphasis on sediment supply qs as the carrier of up system forcings we review experimental numerical and natural examples of source to sink sediment routing and signal propagation during three timescales 1 historic which includes measurement and monitoring of events and processes of landscape change and deposition during decades to centuries 2 centuries to several millions of years referred to as intermediate timescale and 3 deep time we discuss issues related to autogenic dynamics of sediment transport transient storage and release that can introduce noise lags and or completely mask signals of external environmental forcings we provide a set of conceptual and practical tools for evaluating sediment supply within a source to sink context which can inform interpretations of signals from the sedimentary record these tools include stratigraphic and sediment routing system characterization sediment budgets geochronology detrital mineral analysis e g thermochronology comparative analog approaches and modeling techniques to measure calculate or estimate the magnitude and frequency of external forcings compared to the characteristic response time of the sediment routing systems

origin and evolution of the ureilite parent magmas multi stage igneous activity on a large parent body analyses of olivine and pigeonite cores interpreted as cumulate crystals in eight low shock ureilites show well defined correlations between fe x where x is one of the minor elements mn cr ca al ti p or ni and fe mg ratios for the lithophile minor elements these trends are linear with positive slope and pass through or near the origin indicating various degrees of feo reduction of the parent magmas the trends shown by p and ni are consistent with this interpretation and additionally require equilibrium crystallization of 20 27 mole metal graphite was most likely the reducing agent which implies that the ureilites equilibrated at different pressures because the graphite fo2 buffer is pressure dependent there is no evidence for fractionation of olivine or pryroxene in any of these trends the ca ti and al trends show significant scatter indicating that there must have been multiple parent magmas with very similar mg mn and mgcr ratios but different mgal mgca and mgti ratios cao al2o3 ratios vary by a factor of 3 among the eight magmas and are superchondritic 14 32 molar similar to lunar mare basalts we propose the following model for generation and crystallization of ureilite parent magmas upm chondritic material undergoes 10 25 partial melting leaving a plagioclase depleted residue the magma or magmas form a differentiated crust on the ureilite parent body upb with mafic cumulates and plagioclase cumulates spatially separated later remelting 10 of the mafic cumulates produced the upm siderophile elements indicate that the source region of the upm had not experienced segregation of metal such as would occur during core formation in the source region the pressure must have been at least 0 5 1 kb because only at pressures this high does the graphite buffer allow iron oxide to be the stable phase relative to metallic iron the graphite bearing upm were emplaced at various levels in the crust where they were reduced to various extents dependent on depth ureilites are early olivine pigeonite cumulates from these magmas compositions of interstitial low ca pyroxenes indicate that the trapped interstitial liquids from which they crystallized had lower mnmg crmg camg almg and namg ratios than the upm and indicate an abrupt change in liquid composition coincident with impact excavation of ureilites this interstitial material may be derived by mixing a shock melt of nearby olivine pigeonite cumulates with residual primary liquid our model predicts that the upb had a differentiated crust did not have a core and was at least 235 km in radius the lack of a ureilite like body among spectrally analyzed asteroids suggests that either the spectral signature of the upb is not that of ureilites themselves perhaps of carbon free feldspathic material instead that the upb is not intact or that ureilites did not originate in the asteroid belt

lunar volcanic glasses and their constraints on mare petrogenesis abstract volcanic glasses from the apollo 11 14 15 and 16 landing sites have been analyzed for major elements and ni by electron microprobe the 19 varieties of volcanic glass define two distinct chemical arrays that provide new insights into a the petrogenesis of mare basalts and b the structure of the deep lunar interior a simple model is proposed whereby mare basaltic liquids may have been derived from two isolated cumulate systems occurring at depths of 300 km and 400 km each system was itself composed of two lithologic components low ti vs high ti that underwent hybridization assimilation or mixing to generate the large compositional range of magmas observed within each array while the distribution of the two components within each system was locally heterogeneous data indicate that the components themselves were chemically uniform on at least a regional scale the surface correlated volatiles associated with the lunar volcanic glasses seem to have come from some other reservoir within the moon the simplicity of the chemical relationships observed among the lunar volcanic glasses allow specific predictions to be made we believe that they should readily reveal any strengths or weaknesses of this new model

selenium redox cycling during weathering of se rich shales a selenium isotope study abstract selenium isotopes are becoming an important paleoenvironmental proxy however few studies have focused on the behavior of se isotopes during oxidative weathering in this paper a comprehensive set of se isotopic composition and concentration data were collected from the weathering profiles of se rich shales of the permian maokou formation in yutangba and shadi china to investigate se isotopic fractionation and se enrichment during weathering processes the 82 76se in fresh shales 148 118 mg kg se 1sd n 40 from shadi and yutangba drill cores varies from 1 69 to 1 74 with an average of 0 40 0 71 1sd n 40 consistent with the range in other phanerozoic shales suggesting that se isotopes are not strongly fractionated during se sequestration in the primary sedimentary environment however the strongly weathered se rich shales from shadi and yutangba profiles are isotopically lighter with average 82 76se values of 1 96 1 08 1sd n 5 and 1 08 1 83 1sd n 23 respectively these data suggest that se isotopes can be fractionated during oxidation and reduction processes associated with weathering with heavier isotopes removed preferentially during oxidative weathering of shales such a shift if found to be a global phenomenon would have implications for models of the global se cycle and interpretation of se isotope data from past biogeochemical regimes locally altered shales exposed in a quarry at yutangba are extremely enriched in se with 1642 1505 mg kg 1sd n 45 approximately 10 times greater than that in unaltered drill core samples these rocks display very strong variation in 82 76se over short distances with a single 60 cm transect showing the most strongly negative and positive 82 76se values 14 20 to 11 37 observed to date in natural samples this suggests that se has undergone multiple cycles of oxidation mobilization and re reduction resulting in a se rich redox front that has migrated downward through the organic rich shales over time 82 76se values vary sharply over distances as small as 10 cm indicating that se redox conditions change strongly with position and are controlled by fractures and rock layering our data and a simple conceptual model suggest that zones of increased permeability that are accessed first by infiltrating waters are isotopically light whereas less accessible zones are heavy repeated redox cycling accentuates this pattern furthermore the average 82 76se in se rich shales at the yutangba weathering system is 0 45 5 77 1sd n 39 identical with that 0 40 0 71 in fresh shales from same locality implying that se released by weathering accumulates in the redox front with little loss the strong se isotopic fractionation occurring in the redox front implies that se isotopes can be extensively used in tracing geochemical processes of se in groundwater system especially related to fractures

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

enormous ganges brahmaputra sediment discharge during strengthened early holocene monsoon rivers are the main source of terrigenous sediment delivered to continental margins and thus exert a major control on coastal evolution and sequence development however little is known about past changes in fluvial sediment loads despite the recognition of significant variation under changing climatic regimes in this study we present the first quantified estimate of sediment discharge for a major river system under conditions of an intensified early holocene monsoon development of the ganges brahmaputra river delta began ca 11000 yr b p when rising sea level flooded the bengal basin thereby trapping most of the river s discharge on the inner margin chronostratigraphic data from these deltaic deposits are used to calculate the rates of sediment storage on the margin which provide a minimum estimate of the river s past sediment load results reveal that 5 1012 m3 of sediment was stored in the bengal basin from ca 11000 to 7000 yr b p which corresponds to a mean load of 2 3 109 t yr in comparison modern sediment load of the ganges brahmaputra is 1 109 t yr ranking it first among the world s rivers and underscoring the significance of a two fold increase sustained over 4 k y furthermore the timing of immense discharge in the early holocene strongly suggests its relation to a stronger than present southwest monsoon in south asia similar patterns of high monsoon related sediment discharge have been noted throughout the tropics and subtropics suggesting a widespread fluviosedimentary response the potential magnitude of which is showcased by the ganges brahmaputra system

pristine lunar glasses criteria data and implications major element analyses of several thousand glasses from all of the apollo landing sites have resulted in the identification of 25 groups of pristine i e volcanic glass the nickel in these pristine glasses is shown to be indigenous not meteoritic contamination and to be correlated with mg the chemical data indicate that these glasses are consistently better candidates for primary magmas than the majority of crystalline mare basalts the pristine glasses support the view that assimilative processes ringwood and kesson 1976 involving two cumulate systems in the differentiated mantle operated during mare petrogenesis the reality of those assimilative interactions is evident by the occurrence of two linear arrays among the chemistries of the glasses data suggest that these cumulate components in the differentiated mantle persist for lateral distances of at least 1000 km and therefore appear to be products of a vast magma ocean that existed early in lunar history alternative hypotheses claiming that the highlands crust and mare source regions were produced by serial magmatism without a magma ocean have not yet considered all of the constraints derived from the pristine glasses

the depths of the mare basalt source region chemical data for the parental magmas of the nine known vlt array i pyroclastic glasses show statistically significant trends due to olivine fo83 control during their formation by partial melting the compositional scatter is largely due to compositional variations in the source regions on the 1 level this compositional scatter is small when one considers that the scale of the source region is up to 1000 km but is sufficient to make positive identification of the residual phase s in the source regions difficult nevertheless when the effects of the scatter are properly modeled it is relatively clear that olivine is the residual phase in the source region hence these data and additional constraints indicate that the source regions are at shallow depths in the moon

ascent and eruption of a lunar high titanium magma as inferred from the petrology of the 74001 2 drill core abstract an analysis of the orange glasses and crystallized beads from the 68 cm deep 74001 2 core has been conducted to understand the processes occurring during ascent and eruption of the apollo 17 orange glass magma equilibrium between melt and metal blebs fe85ni14co1 within the core along with cr contents in olivine phenocrysts suggest there was an oxidation of c and a reduction of the melt at an o fugacity of iw 1 3 and 1320 c to form co gas at 200 bars or 4 km depth this was followed by development of more oxidized conditions during ascent also during ascent there was formation of euhedral homogeneous fo81 olivine crystals and spinel crystals with higher al and mg contents than the smaller spinels in the crystallized beads both the metal blebs and al rich spinels were trapped inside the fo81 olivine phenocrysts as they grew prior to eruption the composition of the orange glasses are homogeneous throughout the core except for a few distinct glasses at the top that appear to have been mixed in by micrometeorite reworking a few glassy melt inclusions of orange glass composition trapped in the fo81 phenocrysts contain 600 100 ppm s and 50 ppm cl compared to the 200 ppm s and 50 ppm cl in the orange glass melt when quenched these inclusions therefore document the addition of 400 ppm s to the co rich volcanic gas during the eruption the size and distribution of different volcanic beads in the apollo 17 deposit indicate a mode of eruption in which the orange glasses and partially crystallized beads formed further away from the volcanic vent where cooling rates were faster progressively larger and more numerous crystals in the black beads reflect slower cooling rates at higher optical densities in the volcanic plume the development of a brown texture in the orange glasses at the bottom of the core where the black beads dominate is interpreted to result from devitrification by subsolidus heating either as the orange glasses fell back through the hot plume or after deposition on the surface the change from domination by orange glasses to black beads in the core probably reflects a decrease in gas content over time which consequently would increase the plume optical density and favor slower cooling rates

origin of the apollo 14 15 and 17 yellow ultramafic glasses by mixing of deep cumulate remelts abstract we examine the fo2 dependent melting conditions of the apollo 14 yellow intermediate ti ultramafic glasses and the melting processes that formed the full suite of lunar yellow ultramafic glasses multiple saturation experiments indicate that the apollo 14 yellow glass would have been in equilibrium with residual olivine and low ca pyroxene near 1530 c and 2 4 gpa at iw 2 at iw 2 the multiple saturation point moves to greater depth and higher temperature to 1580 c and 3 0 gpa combining the results of this study with that of krawczynski and grove 2012 on more ti rich apollo orange and red glass indicates that the fo2 induced change in multiple saturation pressure correlates with the fe ti molar feo tio2 mgo feo tio2 where tio2 all ti calculated as ti4 of the liquid further a decrease in the olivine fe mg exchange coefficient at lower fo2 suggests that fe2 is complexing more efficiently with ti3 at the expense of mg in the melt than it did with ti4 at higher fo2 processes involving assimilation and or fractionation and or melt wall rock reaction all fail to produce the within suite compositional variability observed in the apollo 14 15 and 17 yellow glasses mixing of remelted source cumulates combined with small amounts of olivine fractionation are the only mechanisms that can reproduce all three trends we present a quantitative model of the mixing process with simultaneous olivine fractionation remarkably the trends can be explained by mixing melts of an ultramafic source olivine pigeonite or orthopyroxene a clinopyroxene ilmenite bearing cumulate and kreep lunar mantle overturn is the most likely process that can reconcile the observed major and trace element compositional characteristics and the experimental results these two constraints are consistent with different models of lunar magma ocean crystallization snyder et al 1992 eklins tanton et al 2011 a complex hot thermal history is necessary to generate the magmas that mixed to form the yellow ultramafic glasses

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

the systematics of light lithophile elements li be and b in lunar picritic glasses implications for basaltic magmatism on the moon and the origin of the moon lunar picrites represented by high mg volcanic glasses are thought to be products of either partial melting of the deep lunar mantle followed by rapid ascent or polybaric partial melting initiated in the deep lunar mantle the near primary compositions of these volcanic glasses provide us with a unique perspective for evaluating basaltic magmatism the characteristics and evolution of the lunar mantle and the origin of the moon the light lithophile elements lle li be b in planetary materials have been used to estimate planetary compositions and evaluate magmatic processes ion microprobe analyses of these glasses for lles were conducted using a cameca 4f ion microprobe this suite of glass beads ranged in tio2 from 0 3 to 17 wt seventy one individual glass beads were analyzed for the lles in addition core rim analyses of individual glass beads were made the lles show a wide range of variability with li ranging from 1 2 to 23 8 ppm be ranging from 0 06 to 3 09 ppm and b ranging from 0 11 to 3 87 ppm b be ranges from 0 40 to 4 6 li be ranges from 2 7 to 41 7 although 90 of the li be values range from 14 to 30 both b be and li be values for the picritic glasses are less than chondrite be nd for the glasses ranges from 04 to 06 and are similar to chondrite 058 traverses across individual beads indicate that they are generally homogeneous with regards to lles regardless of tio2 content the individual glass groups show limited variations in lle characteristics the exceptions to this observation are the a17 vlt and the a15 yellow glasses at individual apollo sampling sites the lle content is generally correlated to tio2 the high ti glasses are displaced toward higher li at similar b and be relative to the very low ti glasses lle concentrations also parallel the enrichments of other lithophile elements such as ba zr sr and rees as noted for other trace element characteristics glasses from each sampling site have similar lle signatures for example the apollo 14 glasses generally have higher lle concentrations relative to glasses of similar tio2 content from other sites the lle data support mantle inhomogeneity and lunar magma ocean lmo cumulate overturn models suggested by previous studies a kreep component had been incorporated into some of these picritic glasses this is consistent with other trace elements and probably reflects the recycling of kreep and or other late stage lmo cumulates into the deep lunar mantle the picritic glasses are compositionally distinct from the crystalline mare basalts in lles they are not related by either fractional crystallization or partial melting processes this suggests that they were derived from distinctively different mantle sources estimates of the bulk compositions of the earth and the moon have previously been made based on the assumption that the ratio of li to be is a direct measure of the ratio of the high temperature condensates htc refractory components to the mg silicates less refractory components in a planet we assert that if li be is to be used to estimate bulk moon composition the picritic glasses provide fewer pitfalls and a better estimate than the crystalline mare basalts differences in partition coefficients d for li and be indicate that fractional crystallization and partial melting will modify the libe ratio estimates based on the picritic glasses infer a higher li be for the bulk moon than estimated from the mare basalts this would indicate that the bulk moon is less refractory than previously calculated by li be and approaches the bulk composition of the earth

detecting eustatic and tectonic signals with carbon isotopes in deep marine strata eocene ainsa basin spanish pyrenees we explore the potential of high resolution carbon isotope stratigraphy to provide an independent record of global sea level changes in a 1600 m thick succession representing 5 m y of slope sedimentation in the eocene ainsa basin of spain the restricted physiographic setting of the basin results in a bulk 13 c carb signal that accurately correlates with the coeval eustatic curve from the new jersey usa passive margin we show that much of the deep water sediment gravity flow sgf deposits are emplaced during eustatic lowstands and fine grained marly intervals between sgfs correlate with rising and highstand sea levels however we also detect a substantial interval of sgf deposition during a sea level highstand confirming the nonuniqueness of the controls on clastic deposition this approach provides a new way to assess the origin of depositional sequences and improve stratigraphic predictions in basins with limited chronostratigraphic control

piping coarse grained sediment to a deep water fan through a shelf edge delta bypass channel tank experiments 1 it is now generally accepted that deltas that prograde to the shelf edge are able to transport coarse sediment to deep water either with or without sea level changes however it is still unclear how feeder rivers behave differently in the shelf edge delta case to rivers found in a delta that progrades over the shelf a series of nine shelf edge delta experiments are presented to investigate the lateral mobility of the feeder channel at the shelf edge and the associated deep water depositional system under a range of sediment supply rates and shelf front depths in the experiments constant sediment supply from an upstream point source under static sea level led the fluviodeltaic system to prograde over the shallow shelf surface and advance beyond the shelf edge into deep water the feeder river of the fluviodeltaic system became a bypass system once the toe of the delta front reached the shelf edge after the delta front was perched at the shelf edge a submarine fan developed in deep water although remaining disconnected from the delta in this bypass stage no regional avulsion or lateral migration of the feeder river occurred and all sediment from the upstream source bypassed the river delta front and shelf front slope the duration of the bypass stage is proportional to shelf front depth and inversely proportional to sediment discharge the combined duration of the shelf transit phase of the fluviodeltaic system and the bypass phase is the characteristic time scale for the continental margin to anneal transgression inducing perturbation due to high frequency and or high amplitude relative sea level rise the sequential evolution in the experiment compares favorably to the eocene sobrarbe formation a shelf edge delta in spain although natural variations are noted this comparison justifies the application of concepts proposed herein to natural systems and provides insight into interpreting processes from ancient shelf edge delta systems

forced regressions in a sequence stratigraphic framework concepts examples and exploration significance sequence stratigraphic concepts suggest that stratal geometries develop and are largely controlled by changes in relative sea level on the shelf lowstand deposits which form during falls and subsequent stillstands of relative sea level can be recognized by the presence of an unconformity at the base the isolated and basinward position relative to the previous shoreline and the abrupt seaward translation of shallow water and shoreline facies into the basin across an unconformity surface this seaward translation of facies and shoreline regression in response to relative sea level lowering is termed a forced regression a forced regression is independent of variations of sediment flux and is in contrast with normal regressions that occur in response to excess sediment flux relative to space available on the shelf i e accommodation forced regressions commonly are associated with a zone of sedimentary bypass subaerial exposure and possible fluvial erosion between the newly formed and preceding shorelines certain shelf sands previously interpreted as offshore or mid shelf sand bodies thus can be reinterpreted as stranded lowstand shorelines associated with forced regressions this alternative interpretation has economic significance insofar as it suggests different subsurface correlations and reservoir geometries with the potential for development of new play types and enhanced recovery in o der fields examples of forced regression can be observed at a variety of scales and ages several such examples include the modern east coulee fan delta and the lower cretaceous viking formation in alberta canada the quaternary rhone delta and the quaternary hudson valley system

origin and occurrence of selenium in some australian coals the analyses are reported of six australian coals for mineral type and content b se speciation by selective leaching and s speciation by selective leaching and xanes together with xanes data for se in one coal from a marine sequence the results of these analyses and of thermodynamic calculations of thiophenes and se analogues are used to suggest that selenoprotein structures in coal s precursors bacteria and algae and possibly higher plants make se bonding in coal unique from that of the other trace elements

lunar regional dark mantle deposits geologic multispectral and modeling studies clementine five channel uv visible uvvis data have been used to study seven regional dark mantle deposits dmds on the moon the dmds were mapped in distribution to determine their extent and stratigraphic relationship to other geologic units based upon the spectral properties for each dmd the crystallization of the beads in each deposit was inferred and used to estimate cooling rates in the volcanic plumes that emplaced the deposits deposits with a high concentration of glasses reflect volcanic plumes that had low optical densities and high cooling rates whereas deposits dominated by crystallized beads indicate plumes with slower cooling rates due to higher optical densities spectral data from each of the regional dmds show that their glass crystallized bead ratio can be estimated based upon their 415 750 and 750 950 nm values and comparison to laboratory spectra for the beads patches of young dark mantle in the sinus aestuum dmd represent one extreme with the bluest color highest 415 750 and weakest glass band absorption lowest 750 950 of all the dmds at the other extreme is the aristarchus plateau dmd with the reddest color and strongest glass band absorption the other nearside dmds including taurus littrow sulpicius gallus rima bode and mare vaporum lie between these two extremes due to intermediate mixtures of the crystallized beads and glasses with other local soils the orientale ring dmd on the western limb is dominated by volcanic glasses and is spectrally similar to the localized dmds found in alphonsus crater we have identified a central vent for the orientale ring dmd and model the eruption as degassing of a near surface dike to produce a 20 km high umbrella shaped plume with ejection velocities of 360 m s and deposition of the glasses at an average radius of 80 km from the vent although we cannot identify the exact sources for the other regional dmds probably because they are buried beneath younger mare the eruptions most likely resulted from dikes breaching the surface and producing a volcanic plume dominated by larger greater than submillimeter hot clasts that formed mare and sinuous rules the small percent of clasts that form the volcanic beads are carried by the expanding gas cloud to large distances in some cases 100 km to produce the observed continuous regional dmds the lack of basalt samples that can be petrologically related to the volcanic glasses may be a result of their spatial separation with the basalts flowing into the basins while the beads are deposited both into the basins and on the adjacent highlands

shelf edge delta overreach at the shelf break can guarantee the delivery of terrestrial sediments to deep water at all sea level stands how and when sediment moves from terrestrial sources to deep water sinks is a significant area of research we have used an array of seismic borehole and gravity core data sets to explore the timing and magnitude of sediment routing to pearl river slope over the last 478 k y as predicted by existing sequence stratigraphic models most sediment dispersal to deep water is shown to have occurred during glacial sea level falls however clastic detritus was still being transported into deep water during interglacial sea level rises we suggest that sediment routing to deep water during interglacial sea level rise is caused by summer monsoon strengthening and resultant warmer and wetter climates both of which have enhanced effective precipitation and sediment supply although some models for the delivery of sediment to deep water basins stress the importance of proximity of canyon heads and coeval shorelines we observed that sediment routing to deep water could occur regardless of the distance between channel head and coeval shorelines in the present case the success of delivery is related to the combined effects of 1 the short duration and high amplitude of sea level oscillations during the past 478 k y and 2 the enhanced sediment supply caused by more humid climates and greater temperature difference between glacial and interglacial period this hypothesis is supported by 1 observations that outer pearl river deltas prograded as an apron over preexisting shelf edges for 10 15 km 6 9 mi and 2 the occurrence of slope channels extending back to prodelta reaches of pearl river shelf edge deltas

constraints on the moon s origin from the partitioning behaviour of tungsten the moon earth and eucritic meteorites display w la ratios which correspond to depletions of w relative to chondrites by factors of 19 ref 1 this depletion can be attributed to metal silicate fractionation ordinary chondrites and cl chondrites with widely varying metal contents and oxidation states have similar w la ratios suggesting that nebular fractionations were unimportant therefore assuming that both w and la are refractory and incompatible the depletions of w relative to la in the earth moon and eucrites are presumably due to separation of metal from silicate during planetary scale igneous events for the moon rammensee and wanke2 concluded that any geophysically reasonable metallic lunar core would be too small to explain the large lunar depletion of w it was therefore suggested2 that the moon acquired its depletion of w in a non lunar igneous event supporting the hypothesis that the moon formed by fission from the proto earth the upper portion of which was depleted in w due to terrestrial core formation3 5 we show here that this conclusion is implicity based on a special case namely equilibrium between metal and silicate phases with total melting of silicates in the geologically more general case where metal fractionates from silicate at relatively low degrees of partial melting the incompatible nature of w may negate this conclusion a geophysically plausible metallic core can account for the depletion of w in lunar surface and presumably lunar mantle rocks the low w la ratio in the moon cannot be used as unconditional evidence for a terrestrial origin of the moon

mercury distribution in coals influenced by magmatic intrusions and surface waters from the huaibei coal mining district anhui china the hg concentrations in 108 samples comprising 81 coal samples 1 igneous rock 2 parting rock samples and 24 water samples from the huaibei coal mining district china were determined by cold vapor atomic fluorescence spectrometry the abundance and distribution of hg in different coal mines and coal seams were studied the weighted average hg concentration for all coal samples in the huaibei coalfield is 0 42 mg kg which is about twice that of average chinese coals from southwestern to northeastern coalfield hg concentration shows a decreasing trend which is presumably related to magmatic activity and fault structures the relatively high hg levels are observed in coal seams nos 6 7 and 10 in the southwestern coal mines correlation analysis indicates that hg in the southwestern and southernmost coals with high hg concentrations is associated with pyrite the hg concentrations in surface waters in the huaibei coal mining district range from 10 to 60 ng l and display a decreasing trend with distance from a coal waste pile but are lower than the regulated levels for hg in drinking water

quality parameters of lignite of the north bohemian basin in the czech republic in comparison with the world average lignite abstract sulfur is considered to be the most harmful element in atmospheric emissions and fall out which originate from coal combustion total sulfur content std in lignites of the north bohemian basin nbb has a geometric mean of 1 61 wt at n 12 979 and is mostly influenced by the presence of iron disulfides the distribution of sulfur and many trace elements is log normal a non uniform distribution of sulfur in lignite was found within the basin with the lowest std contents i e not exceeding 1 wt s confined to the eastern and southeastern margin of the nbb contents between 1 and 1 5 wt s are most common in lignites of the south central nbb lower sulfur contents were identified in the area of the atec delta and its northern extension in contrast high contents of sulfur in lignite exceeding 1 5 wt are found along the northern margin of the basin at the foot of the krusne hory mts and in the westernmost part of the nbb three genetically different types of iron disulfides occur in lignite of the nbb synsedimentary early diagenetic diagenetic and epigenetic among those forms synsedimentary disulfides mostly pyrite appear to be most abundant they form finely dispersed microscopic framboids or veinlets that commonly parallel the coal bedding the other iron disulfide forms are much less abundant dissolved sulfate which was supplied to the nbb during the miocene is likely to have been derived from sulfides of the krusne hory mts crystalline complex this unit has an isotopic composition of sulfide sulfur varying between 1 and 5 consequently the sulfate supplying the nbb should exhibit slightly positive 34 s values syngenetic pyrites forming microframboids or veinlets in coal show 34 s values close to 0 these values are similar those of sulfur dioxide in gases of power stations burning nbb coal this implies that no considerable shifts in sulfur isotopic composition occur during thermal oxidation of the dominant pyrite arsenic is positively correlated with sulfur r2 0 89 its total content astd is 20 53 ppm at n 9172

the mare basalt magma source region and mare basalt magma genesis given the available data we find that the wide range of mare basaltic material characteristics can be explained by a model in which 1 the mare basalt magma source region lies between the crustmantle boundary and a maximum depth of 200 km and consists of a relatively uniform peridotite containing 73 80 olivine 11 14 pyroxene 4 8 plagioclase 0 2 9 ilmenite and 1 1 5 chromite 2 the source region consists of two or more density graded rhythmic bands whose compositions grade from that of the very low tio2 magma source regions 0 2 ilmenite to that of the very high tio2 magma source regions 9 ilmenite these density graded bands are proposed to have formed as co crystallizing olivine pyroxene plagioclase ilmenite and chromite settled out of a convecting magma which was also parental to the crust in which these crystals were suspended since the settling rates of the different minerals were governed by stoke s law the heavier minerals settled out more rapidly and therefore earlier than the lighter minerals thus the crystal assemblages deposited nearest the descending side of each convection cell were enriched in heavy ilmenite and chromite with respect to lighter olivine and pyroxene and very much lighter plagioclase the reverse being the case for those units deposited near the ascending sides of the convection cells simultaneously with this density controlled settling of the crystals the heating of the magma at the bottom of the convection cells resulted in the partial remelting of significant amounts of suspended but settling plagioclase ilmenite and pyroxene this partial remelting process was also partially responsible for the decrease in the ilmenite content from 9 to 0 2 between the very high tio2 and the very low tio2 source regions and caused the plagioclases and pyroxenes in the former source regions to be more sodic and clinopyroxene richer respectively than in the latter 3 during the mare basalt epoch radiogenic induced remelting of various parts of the density graded bands led to the formation of the initial mare basalt magmas the viscosity of melting systems which decreases rapidly at about 30 5 partial melting appears to have limited the degree of partial melting of the source region to about 30 2 4 these 30 partial melts rose to the crust mantle boundary where they pooled in magma storage chambers the magmas remained in these chambers for different lengths of time cooled to different degrees and lost 0 to 30 olivine or 30 olivine plus 0 to 20 pyroxene by fractional crystallization those magmas which remained in the chambers for very short times and lost no or essentially no olivine before eruption were the parental magmas of the pyroclastic glass units those magmas which lost increasing amounts of olivine pyroxene were the parental magmas of the apollo 12 and 15 magmas the apollo 11 and 17 magmas and the luna 16 and 24 magmas respectively this fractional crystallization phase in the genesis of the magmas explains both the pattern of the mare basalt magmas in the pseudo quaternary phase diagrams and the decrease in the siderophile contents of the magmas as a function of their degree of fractionation 5 the magma storage chambers being located at the crust mantle boundary were located in the zone where urkreep formed during the initial differentiation of the moon due to the low melting point of kreep compared with the initially high temperatures of the magmas residuals of the urkreep layer were assimilated by the cooling magmas since the urkreep materials underwent varying degrees of fractional melting early in lunar history these urkreep residuals had varying degrees of light ree depletion thus the assimilation of up to a few percent of these residuals caused the magmas to have differing eu and light ree depletion patterns as well as a wide range in their ree abundances 6 the fractional crystallization and urkreep residual assimilation phase of mare basalt magma genesis ended with the eruption of the magmas onto the lunar surface

reconstructing chemical weathering physical erosion and monsoon intensity since 25 ma in the northern south china sea a review of competing proxies reconstructing the changing strength of the east asian summer monsoon has been controversial because different proxies many being indirect measures of rainfall tell contrasting stories about how this has varied over long periods of geologic time here we present new sr isotope grain size and clastic flux data and synthesize existing proxies to reconstruct changing chemical erosion in the northern south china sea since the oligocene using the links between weathering rates and monsoon strength established in younger sediments as a way to infer intensity chemical proxies such as k rb l al and the chemical index of alteration cia together with clay proxies like kaolinite illite chlorite show a steady decline in alteration after a sharp fall following a maximum at the mid miocene climatic optimum mmco 15 5 17 2 ma probably as a result of cooling global temperatures in contrast physical erosion proxies including bulk ti ca and clastic mass accumulation rates mar show peaks at 21 23 ma similar to 19 ma and 15 5 17 2 ma implying faster run off in the absence of drainage capture rates increase again likely driven by slightly increased run off after 13 ma but decrease after 8 ma which is identified as a period of summer monsoon weakening sr isotope composition correlates with hematite goethite and the spectral proxy crat to show stronger weathering linked to more monsoonal seasonality these proxies argue for a strengthening of the east asian monsoon after 22 23 ma followed by an extended period of monsoon maximum between 18 and 10 ma then weakening there is some suggestion that the summer monsoon may have strengthened since 3 4 ma after reaching a minimum in the pliocene c 2014 elsevier b v all rights reserved

occurrence of native selenium in yutangba and its environmental implications rare native se has been discovered in yutangba enshi city hubei province china where a sudden incidence of se poisoning occurred in the early 1960s it was first found in a small area where native se was produced on a large scale and was diverse in forms due to different formation mechanisms genetically native se can be divided into 3 categories the primary native se occurring in carbonaceous siliceous rocks and tiny se crystals formed in cracks of rocks during tectonic activities micro se crystals formed in the weathering processes of se rich rocks and larger se crystals derived from natural burning of stone coal on the subsurface of abandoned stone coal spoils the different forms of native se found in yutangba demonstrate that se can be activated transformed remobilized and enriched at special sites such as in the unsaturated subsurface zone or in the saturated zone this discovery of native se has not only resolved a long standing controversial question on modes of occurrence of se which has puzzled many researchers in china but has provided new possible evidence for the pathogenic explanation of the sudden prevalence of se poisoning in yutangba the research results also have important implications for studying the mineralogy ore geochemistry and environmental geochemistry of se

geochemistry of trace elements in chinese coals a review of abundances genetic types impacts on human health and industrial utilization abstract china will continue to be one of the largest coal producers and users in the world the high volume of coal use in china has focused attention on the amounts of toxic trace elements released from coal combustions and also the valuable trace elements extracted or potentially utilized from coal ash compared to world coals chinese coals have normal background values for most trace elements with the exception of higher li 31 8 g g zr 89 5 g g nb 9 44 g g ta 0 62 g g hf 3 71 g g th 5 84 g g and rare earth elements la lu y 136 g g this is not only due to the higher ash yields of chinese coals but also to alkali volcanic ashes found in some southwestern coals the background values of toxic elements of hg 0 163 g g as 3 79 g g and f 130 g g in chinese coals are comparable to coals from most other countries the genetic types for trace element enrichment of chinese coals include source rock controlled marine environment controlled hydrothermal fluid controlled including magmatic low temperature hydrothermal fluid and submarine exhalation controlled subtypes groundwater controlled and volcanic ash controlled the background values of trace elements were dominated by sediment source regions low temperature hydrothermal fluid was one of the major factors for the local enrichment of trace elements in southwestern china serious human health problems caused by indoor combustion of coal in china include endemic fluorosis arsenosis selenosis and lung cancer endemic fluorosis mainly occurring in western guizhou was mostly attributed to the high fluorine in clay that was used as a briquette binder for fine coals in addition to a small quantity of fluorine from coal fluorine in the coal from endemic fluorosis areas of western guizhou is within the usual range found in china and the world endemic arsenosis in southwestern guizhou is attributed to indoor combustion of high as coal endemic selenosis in enshi of hubei was due to high se in carbonaceous siliceous rocks and carbonaceous shales fine particles of quartz released into air during coal combustion are hypothesized as a possible cause for the lung cancer epidemic in xuanwei yunnan china valuable elements including ge ga u ree rare earth element nb zr and re are concentrated to levels comparable to conventional economic deposits in several coals or coal bearing strata in china the ge deposits at lincang yunnan province and wulantuga inner mongolia have been exploited and industrially utilized the enrichment of ge in the two deposits was caused by hydrothermal fluids associated with adjacent granitoids the ga al ore deposit in the jungar coalfield inner mongolia was derived from the neighboring weathered and oxidized bauxite of the benxi formation pennsylvanian the nb ta zr hf ree ga deposits in the late permian coal bearing strata of eastern yunnan and chongqing of southwestern china were attributed to ashes of the alkali volcanic eruptions

seventh foray whitlockite rich lithologies a diopside bearing troctolitic anorthosite ferroan anorthosites and kreep seventeen nonmare samples most of them pristine are characterized and implications of the new data are discussed five pristine samples are from apollo 14 near the center of the kreep rich zone in the moon s western hemisphere three of them are alkali anorthosites rich in ca phosphate whitlockite which apparently crystallized from magmas with ree contents roughly 6 those of high k kreep the alkali anorthosites probably formed from mg rich magmas that assimilated large amounts of urkreep but some might have formed by metasomatism of ferroan anorthosite by urkreep the gabbronorite norite classification scheme is not well suited to western hemisphere lithologies probably due mainly to the overriding effects of longitude petrochemistry correlations a diopside bearing mg rich lithology indicates that a low degree of melting was not a prerequisite for producing gabbroic high ca pyroxene rich mg rich magmas and suggests that some source regions of mg rich magmas were relatively ca rich several pristine kreep fragments from apollo 15 station 2 are texturally and compositionally much like other pristine kreep and thus reinforce the evidence that kreep is highly uniform the pristine anorthosites on the other hand demonstrate further that lunar anorthosites are diverse

mare glasses from apollo 17 constraints on the moon s bulk composition two previously unreported varieties of mare volcanic glass have been discovered in apollo 17 samples twenty three chemical types of volcanic glass have now been analyzed from the six apollo landing sites these volcanic glasses which may be samples of primary magmas derived from the differentiated lunar mantle define two linear arrays that seem to reflect regional if not global regularities among the source regions of these melts additional systematics among these glasses have been used to estimate the bulk composition of the moon the results suggest that the refractory lithophile elements e g ca al ti ree u are present at abundances of 1 7 chondrites the silicate portion of the moon appears to have a major element composition similar to a volatile si na k depleted earth s upper mantle the theory involving an earth fission origin of the moon can be tested further through trace element analyses e g ni on the volcanic glasses and through determination of the n 36ar ratio and noble gas isotopes from primordial lunar gas trapped within vesicles associated with mare volcanic glass

the parental magma of the nakhla achondrite ultrabasic volcanism on the shergottite parent body the nakhla meteorite is an augite rich igneous cumulate rock magma trapped among the cumulus grains is now represented by fine grained mesostasis and post cumulus overgrowths on cumulus grains the composition of the intercumulus magma calculated by mass balance is ultrabasic sio2 45 and enriched in incompatible elements lalu 6 ci the cumulus augite and intercumulus magma were in chemical equilibrium implying that the intercumulus magma is a sample of nakhla s parental magma complex processes like infiltration metasomatism were therefore unimportant nakhla contains olivine crystals which are as large or larger than the cumulus augite crystals the largest olivine crystals probably xenocrysts preserve core compositions too fe rich to have been in equilibrium with the intercumulus magma other smaller olivine grains may have been phenocrysts the closest terrestrial analogs to nakhla and the other nakhlites are pyroxene rich cumulate layers in differentiated picrite and komatiite flows and shallow sills spinel or garnet was fractionated from the parental magmas of the nakhlites or their parental mantle based on the superchondritic caoal2o3 ratio of nakhla s intercumulus magma and its lack of an eu anomaly the three nakhlites and chassigny are half of the known samples of the shergottite parent body spb one may tentatively infer that ultrabasic volcanism was much more important on the spb than on the moon eucrite parent body or present day earth

magmatic processes that produced lunar fire fountains reanalysis of the apollo 15 a b and c green glass beads from slide 15426 72 led to the discovery of patchy highly vesicular glass rims adhering to beads these rims are high in s and ni and low in mgo but otherwise compositionally similar to the green glasses we find that these rims represent a unique melt composition that places constraints on lunar magmatic processes combining the compositional data for the vesicular glass rims with new minor element data for the green glass beads leads us to hypothesize that the vesicular rim fluid originated near the green glass source at about 2 2 gpa these findings support the theory of a heterogeneous lunar mantle and suggest that sulfur did not drive the eruption from depth but that degassing volatiles into the vacuum did drive the final fire fountain eruption

late quaternary east asian monsoon variability in the south china sea evidence from planktonic foraminifera faunal and hydrographic gradient records the surface hydrographic conditions of the south china sea scs are influenced strongly by fluctuations of the east asian monsoon eam long term fluctuations of the eam have been previously investigated through analysis of several proxy records obtained from scs sediment cores however in this marginal sea interpretation of these records is complicated by ice volume sea level effects here we have extracted east west hydrographic gradients from two images core records in the scs which are proposed to indicate monsoon variability this strategy minimizes the effect of ice volume sea level on the monsoon signal highresolution records of planktonic foraminifer faunal assemblages and sea surface temperature sst of the last 135 kyr have been generated for two cores taken off the vietnam margin md012394 in the western scs and near palawan island md972142 in the southeastern scs these core sites represent contrasting hydrographic conditions in modern monsoon climates where the winter eam drives cold and strong mixing conditions in the western scs but maintains warm and deep thermocline conditions in the southeastern scs a planktonic foraminifera hydrographic index pfhi is established based on the abundance ratios of warm thermocline and cold mixing species assemblages and sst estimates from a modern analogue technique mat the records of the east west gradients for pfhi pfhi and for sst sst between the two cores md012394 and md972142 show a dominance of 23 kyr precession cycles in the precession cycles the pfhi and sst increased at the december 21 perihelion which is associated with seasons of minimum northern hemisphere winter and maximum southern hemisphere summer insolation cross spectral analysis between pfhi sst and the precession cycles indicates coherent and in phase relationships considering that the december 21 perihelion of the cycle of precession accorded with the time of maximum summer insolation in the southern hemisphere we suggest that the scs variability of hydrographic gradients for the last 135 kyr has been dominated by winter monsoon dynamics in response to geographic forcing controlled by the strength of the australian summer monsoon

geology geography and humans battle for dominance over the delivery of fluvial sediment to the coastal ocean abstract sediment flux to the coastal zone is conditioned by geomorphic and tectonic influences basin area and relief geography temperature runoff geology lithology ice cover and human activities reservoir trapping soil erosion a new model termed bqart in recognition of those factors accounts for these varied influences when applied to a database of 488 rivers the bqart model showed no ensemble over or underprediction had a bias of just 3 across six orders of magnitude in observational values and accounted for 96 of the between river variation in the long term 30 years sediment load or yield of these rivers the geographical range of the 488 rivers covers 63 of the global land surface and is highly representative of global geology climate and socioeconomic conditions based strictly on geological parameters basin area relief lithology ice erosion 65 of the between river sediment load is explained climatic factors precipitation and temperature account for an additi

ion microprobe studies of trace elements in apollo 14 volcanic glass beads comparisons to apollo 14 mare basalts and petrogenesis of picritic magmas abstract the major element geochemistry of picritic lunar glass beads indicates that they represent primary basaltic liquid compositions and as such provide unique information concerning the origin of mare basalts and characteristics of the lunar interior this study used ion microprobe techniques for trace element analysis of individual glass beads representing seven compositionally distinct types of picritic glass beads from the apollo 14 site high ti glasses 17 11 tio2 red black orange intermediate ti glasses 5 4 tio2 yellow low ti glasses 2 8 tio2 lap low alkali picritic papike et al 1989 very low ti glasses ba sr 1 of these glasses are different from low ti mare basalts at other sites but are similar to crystalline basalts at the apollo 14 site the intermediate to high ti picritic glasses exhibit a flat to slightly positive lree slope and a negative hree slope the orange glass has a higher total ree abundance and a slightly larger negative eu anomaly than the red black and yellow glasses relative to the apollo 17 high ti glasses apollo 14 high ti glasses are enriched in ree lree hree y v zr sr ba and ba sr and are similar in alkali elements li rb co and sc trace element modeling within the context of liquid lines of descent and major element characteristics indicates that the picritic glass beads at the a 14 site are not related by low pressure fractional crystallization to each other or to crystalline basalts at the apollo 14 or other landing sites a possible exception is the relationship between lap and basalts of the high al basalt suite the wide range of primary magma compositions and the lack of petrogenetic linkage via crystal fractionation to crystalline basalts indicates that either a wide compositional range of evolved mare basalts has not yet been sampled or a unique mechanism is selectively tapping these picritic magmas directly from their mantle source region the wide range of major and trace element characteristics of the volcanic glass beads is consistent with derivation from mineralogically distinct sources which consist of varying proportions of olivine orthopyroxene clinopyroxene ilmenite plagioclase kreep component the evolved kreep component may have been incorporated into these primary picritic magmas by either assimilation fractional crystallization type processes afc or by hybridization of the mantle source the former appears less likely due to the general systematic increase in incompatible elements relative to ti concentration and the apparent lack of crystallization that is required in afc type models the hybridization processes may be the result of sinker mechanisms as proposed by ringwood and kesson 1976 a manifestation of original mantle inhomogeneities or a magma ocean stirred by large impacts

high selenium in the carboniferous coal measures of northumberland north east england the carboniferous lower and middle coal measures coals of the northumberland coalfield are anomalously rich in selenium se content up to 62 ppm compared to the averages for the common uk and worldwide coals as well as posing an environmental toxicity threat se is now regarded as an important resource for alloys photovoltaic products and nanotechnologies and high se coals in north east england offer an opportunity to assess the se means of occurrence origins transport mechanisms and enrichment in coals at least two generations of pyrite host high se in the sampled coal seams microbial formed disseminated pyrite both cubic and framboidal in habit and later cleat filling pyrite identified by petrographic observations laser ablation methods and sulphur isotope compositions there is a notable se enrichment of up to 250 ppm in later formed cleat filling pyrite trace element enrichment may have been sourced and influenced by seawater distribution during diagenesis and localised dykes and deformation may have acted as an enrichment mechanism for sampled seams in the region the high se coals in northumberland may provide a potential e tech element source and should be considered and carefully managed as coal mining and production are reduced in the area the study also highlights the nature of se enrichment in pyritic coals affected by cleat formation and multiple episodes of mineralisation important as critical element demand continues to increase worldwide

a three component model for the bulk composition of the moon abstract using detailed analyses of lunar pristine glasses as a basis delano 1986 we present a suite of models of lunar bulk composition which are based on the following assumptions i that the early moon differentiated into two primary reservoirs 1 an feo rich magma ocean and 2 an olivine rich residuum of fo90 and ii that this magma ocean then differentiated into an olivine dominated cumulate fo80 and a primitive liquid composition ppg thus in these models the bulk composition of the moon is given by a mixture of three components an early olivine residuum a later olivine orthopyroxene cumulate and ppg liquid with the constraint that the moon possess a ci chondritic mg al ratio our model lunar compositions are grossly similar to the lunar composition of ringwood et al 1987 and when projected from feo they appear very similar to the composition of the earth s upper mantle again when projected from feo our model magma ocean compositions are very similar to the bulk lunar composition derived by taylor 1982 remelting of cumulates from the magma ocean can produce the mare basalts and the pristine glasses remelting of the early residuum may be the source of the highly magnesian olivines found in the lunar highlands our ability to relate such diverse chemistries as the earth s mantle and taylor s moon is relatively model independent the model compositions discussed above are generated by assuming that the cumulate formed by equilibrium crystallization to better determine if there is a significant difference between the feo contents of the earth and the moon we have also calculated bulk lunar compositions whose cumulate component is formed by fractional crystallization a more realistic approximation we find that if the mg si ratios of the earth and moon are similar and if the early residue is dominated by olivine then the bulk silicate moon is 25 to 50 enriched in feo over the earth s upper mantle 10 to 13 wt feo for the moon as compared to 8 wt for the earth again the ultimate basis for this estimate of lunar feo is the set of lunar pristine glasses a characteristic of all our models is that refractory lithophile elements such as ca and al are calculated to be 2 to 3 times ci in the bulk silicate moon these abundances are largely determined by our requirement that the moon possess a chondritic mg al ratio to emphasize this point we discuss the implications of the choices of various mg al and mg si ratios in the calculation of bulk planetary compositions

reconstructing the end of the appalachian orogeny in contrast to crustal deformation observed in the actively forming himalayas where shallowly dipping crustal detachments extend over hundreds of kilometers prior work on the paleozoic southern appalachian orogeny inferred that the final continental collision occurred on a steeply dipping crustal suture permitting collision models that are dominated by strike slip motion here we use scattered seismic phases to instead reveal the appalachian alleghanian crustal suture as a low angle 15 southward dipping interface that soles into a flat lying mid crustal detachment the observed suture geometry implies more than 300 km of head on shortening across a plate boundary structure similar to the himalayan mid crustal detachment indicating that this mode of deformation has been fundamental in continental collisions over hundreds of millions of years

seven ambiguities in the mediterranean palaeoenvironmental narrative abstract a review of seven outstanding issues on mediterranean palaeoenvironments is presented these are related to the dominant orbital pacing of climate variability the length of the interglacial vegetation succession the influence of the african summer monsoon the seasonality of precipitation during boreal insolation maxima the moisture balance during glacial maxima and the appearance of the mediterranean type climate rhythm and evolution of mediterranean sclerophyllous plants what emerges is that 1 marine 18oplanktonic and sst records show that precession has been a fundamental tempo of mediterranean climate change representing both a low latitude signal runoff from north africa and the direct influence of insolation at mediterranean latitudes but high latitude glacial effects 41 kyr and 100 kyr cycles became superimposed after 2 8 ma sapropel and dust deposition patterns in marine cores reveal that obliquity also has an effect on mediterranean climate through dry wet oscillations which are independent of glacial interglacial variability 2 the temperate part of interglacial vegetation succession has a duration of approximately half a precession cycle this persisted during the interval of obliquity dominated glacial cycles 2 8 1 ma with distinct forest successions following the precessional cycles however these are not always separated by an open vegetation phase because of minimal ice growth producing an impression of a prolonged interglacial forest interval 3 the effect of an enhanced african monsoon during summer insolation maxima has been mainly indirect in terms of nile discharge and runoff along the north african coast leading to increased freshwater input into the mediterranean sea reduced deep water ventilation and sapropel deposition 4 the notion of an accentuated summer rain regime in the northern mediterranean borderlands also contributing to a freshening of the mediterranean sea during boreal insolation maxima is not supported by the available evidence which suggests increased summer aridity 5 recent improvements in chronological precision and data resolution point to an increase in aridity and decreased temperatures during the last glacial maximum 21 2 ka but suggest an increase in effective moisture during the immediately preceding interval of 24 27 ka 6 the mediterranean type climate is not exclusively a post 3 6 ma phenomenon but may have appeared intermittently during the course of the tertiary or before 7 if that is the case then the paradigm that the sclerophyllous evergreen habit represents a pre adaptation to summer drought may need re evaluation

basaltic magmatism on the moon a perspective from volcanic picritic glass beads abstract it is widely accepted that basaltic magmas are products of partial fusion of periodotite within planetary mantles as such they provide valuable insights into the composition structure and processes of planetary interiors those compositions which approach primary melt compositions provide the most direct information about planetary interiors and serve as a starting point to understand basaltic evolution within the collection of lunar samples returned by the apollo and luna missions are homogeneous picritic glass beads of volcanic origin these picritic glasses are our closest approximations to primary magmas as such these glass beads provide a unique perspective concerning the origin of mare basalts the characteristics of the lunar interior and processes in the early differentiation of the moon we have obtained trace element data for these picritic glasses using sims techniques these data and literature isotopic and experimental data on the picritic glasses are placed within the framework of mare basaltic magmatism the volcanic glasses are very diverse in their trace element characteristics for example they have a wide range of ree pattern shapes and concentrations like the crystalline mare basalts all picritic glasses have a negative eu anomaly unlike the crystalline mare basalts there is little correlation between the size of the eu anomaly and overall ree concentrations trace element differences among the various glasses suggests that a kreep component was incorporated into their mantle source this implies large scale mixing of the lunar magma ocean derived cumulate pile subtle differences among glasses suggest that local mixing of sources may also have been an important process preservation of subtle chemical differences in the picritic glasses and crystalline basalts may be interpreted as indicating that they were produced by small to moderate degrees of partial melting and that the lunar mantle did not experience extensive melting during episodes of mare volcanism several lines of evidence are consistent with the view that the picritic glasses were derived from mantle sources that were compositionally distinct from the sources for crystalline mare basalts these are parallel but no common liquid lines of descent chemical differences between picritic glasses and the more primitive crystalline mare basalts experimental studies indicating that the picritic glasses are multiply saturated at depths greater than that of the mare basalts differences in lead isotopic data and the mode of eruption i e fire fountaining for glass beads these data also provide circumstantial evidence that suggests that the picritic glasses were derived from a source somewhat more volatile rich than that of the mare basalts several petrogenetic models are suggested by the trace element characteristics of the picritic glasses 1 1 partial melting of heterogeneous lunar mantle at depths greater than 300 km to produce the parental magmas picritic for both the mare basalts and picritic glasses picritic magmas represented by glass beads were erupted to the surface with small degrees of fractional crystallization while mare basalts were produced by larger degrees of fractional crystallization 15 30 of similar but not identical picritic magmas 2 2 picritic magmas represented by the glass beads were generated at depths greater than 400 km in a volatile enriched relative to the mare basalt source heterogeneous mantle while mare basalts are fractional crystallization products of picritic magmas generated at depths of less than 400 km 3 3 the picritic magmas represented by the glass beads represent polybaric melting that initiated at depths of at least 1000 km a primitive mantle component or less processed cumulate mantle components may have been involved in the generation of the picritic glasses in any of these models

trace element identification of three chemically distinct very low titanium vlt basalt glasses from apollo 17 abstract lunar basaltic samples of vlt very low titanium composition occur primarily as small glass fragments in the regolith at the apollo 17 landing site electron microprobe analyses of glasses from the double drive tube 79001 2 90 150 m size fraction of soils from mean depths of 0 8 16 8 cm indicate that 34 of 90 38 are of vlt composition a subset of twenty glasses was removed from the thin sections using a micro coring device and analyzed using special micro inaa techniques to obtain major and trace element abundances on the basis of the results we delineate three distinct groups which have been named for their relative amounts of co hico meco and loco apollo 17 vlts the most magnesian hico basalt glasses 4 of 34 or about 12 of the vlt glasses are probably pristine pyroclastics soil breccias 79135 and 70295 apparently contain only this type of vlt glass the medium co meco glasses 6 of 34 18 strongly resemble the largest sample of vlt composition the olivine vitrophyre 78526 as well as all three of the apollo 17 vlt lithic fragments that have been analyzed for trace elements the loco vlt glasses 23 of 34 68 are more enigmatic trace element concentrations require that these three vlt compositions cannot be related by simple igneous processes the distribution of the three types provides important information on the sequence of events that produced the regolith at the apollo 17 site

importance of the lu hf isotopic system in studies of planetary chronology and chemical evolution the 176lu 176hf isotope method and its applications in earth sciences are discussed greater fractionation of lu hf than sm nd in planetary magmatic processes makes 176hf177hf a powerful geochemical tracer in general proportional variations of 176hf177hf exceed those of 143ndl44nd by factors of 1 5 3 in terrestrial and lunar materials lu hf studies therefore have a major contribution to make in understanding of terrestrial and other planetary evolution through time and this is the principal importance of lu hf new data on basalts from oceanic islands show unequivocally that whereas considerable divergences occur in 176hf177hf 87sr86sr and 143ndl44nd 87sr86sr diagrams 176hf177hf and 143nd144nd display a single linear isotopic variation in the suboceanic mantle these discordant 87sr86sr relationships may allow with the acquisition of further hf nd sr isotopic data a distinction between processes such as mantle metasomatism influence of seawater altered material in the magma source or recycling of sediments into the mantle in order to evaluate the hf nd isotopic correlation in terms of mantle fractionation history there is a need for measurements of hf distribution coefficients between silicate minerals and liquids and specifically for a knowledge of hf behavior in relation to rareearth elements for studying ancient terrestrial hf isotopic variations the best quality hf isotope data are obtained from granitoid rocks or zircons new data show that very u pb discordant zircons may have upwardly biased 176hf177hf but that at least concordant to slightly discordant zircons appear to be reliable carriers of initial 176hf177hf until the controls on addition of radiogenic hf to zircon are understood combined zircon whole rock studies are recommended lu hf has been demonstrated as a viable tool for dating of ancient terrestrial and extraterrestrial samples but because it offers little advantage over existing methods is unlikely to find wide application in pure chronological studies

development of submarine canyons after the mid pleistocene transition on the ebro margin nw mediterranean the role of fluvial connections after the messinian salinity crisis msc the ebro margin like other mediterranean deltaic margins rebuilt through progradation and increasingly significant aggradation the plio quaternary transition from a ramp like system to a new margin with large clinoforms is an opportunity to understand the processes that govern canyon initiation and evolution we used a 3d seismic data set located at the outer shelf upper slope of the ebro margin we tied major bounding surfaces to chrono stratigraphic constraints from borehole data or for the most recent interval from averaged accumulation rates derived from borehole stratigraphy the major shelfal erosion surfaces are interpreted as sequence boundaries tied to major glacial maxima along these surfaces seismic attributes characterize the fluvial canyon connection viewed as one of the key factors in canyon development the first appearance of proto canyons dense networks of channels and gullies 50 100 m deep and 1 2 km wide occurs in the late zanclean their size increased progressively throughout the pliocene and early quaternary in relation to the increase in clinoform heights true canyons with distinct interfluves more than 200 m deep and 3 4 km wide appeared during the mid pleistocene transition mpt 1250 700 ka bp the first evidence of direct connection between canyon heads and fluvial systems is observed during marine isotope stage 22 one of the most pronounced glacial stages of the quaternary similar connections also existed at least during mis 16 and mis 12 which are also stages of pronounced low sea level the topography of fluvial channels in the outer shelf is not imaged in detail in the picked horizons at the resolution of our seismic data but sinuous fluvial systems are very well imaged through amplitude and coherency attributes direct connection of fluvial systems during and after mis 22 also favored headward erosion and the formation of shelf indenting canyons probably during early phases of sea level rise

plio quaternary sedimentation processes and neotectonics of the northern continental margin of the south china sea abstract analyses of over 6600 km of reflection seismic profiles on the northern continental margin of the south china sea permit the recognition of four quaternary high frequency type 1 sequences of the 4th order deposited during the past ca 690 kyr at the present day shelf edge only lowstand systems tracts characterised by a prograding clinoformal internal reflection pattern are preserved the prograding complexes can be considered as regressive units accumulated during relative sea level falls they exhibit internal discontinuities which might point to minor sea level fluctuations of the 5th order a preliminary regional relative sea level curve for the past 630 kyr is established using the present positions of the delta fronts mapped the neotectonics curve derived by subtracting eustatic sea level changes from the relative sea level curve shows that the depths of the delta fronts today are controlled primarily by regional tectonic movements and the global sea level our seismo stratigraphic interpretation documents that the area off hong kong and around the dongsha islands experienced two uplift episodes during the past 5 ma namely at the miocene pliocene boundary and at the end of the lower middle pleistocene respectively these uplift events which are centred on the dongsha rise led to its subaerial exposure and to the erosion of the pliocene and most of the pleistocene strata the change from thermal subsidence of the continental margin initiated at the end of the drift phase to the phase of magmato tectonic uplift was caused by a reorientation of the tectonic regime the recent depositional environment on the northern continental margin of the south china sea is dominated by sediment accumulation within the inner shelf and the zhujiang pearl river estuary the outer shelf and upper slope especially around the dongsha islands are characterised by bypass of terrigenous material the sedimentary column in the deepsea basin has a thickness of more than 2 km and comprises 14 depositional units starting with terrestrial rift deposits it overlies oceanic as well as transitional crust

apollo 17 regolith 71501 262 a record of impact events and mare volcanism in lunar glasses thirteen glasses from apollo 17 regolith 71501 262 have been chemically analyzed by electron microprobe and isotopically dated with the 40ar 39ar dating method we report here the first isotopic age obtained for the apollo 17 very low titanium vlt volcanic glasses 3630 40 ma twelve impact glasses that span a wide compositional range have been found to record ages ranging from 102 20 ma to 3740 50 ma the compositions of these impact glasses show that some have been produced by impact events within the apollo 17 region whereas others appear to be exotic to the landing site as the data sets that include compositions and ages of lunar impact glasses increase the impact history in the earth moon system will become better constrained

case study of the igneous intrusion effect on the mineralogical composition of the carboniferous coal from jingxi coalfield north china igneous intrusions significantly affect the mineralogical composition of coal the jingxi coalfield north china was subjected to the intrusion of a mesozoic aplite however the resulting coal mineralogy has not been well investigated this paper reports on a study of the mineralogical composition of five coal bench samples collected from the no m3 coal in the jingxi coalfield which was intruded by an aplite sill along the roof the minerals present in the highest proportions in the no m3 coal are margarite paragonite group mineral 21 4 and ammonian illite 72 7 followed by ankerite 4 2 anatase 0 7 and rutile 0 9 the formation of margarite paragonite and ammonian illite is attributed to the intrusion of the aplite sill the margarite and paragonite were formed prior to the formation of the ammonian illite the proportion of the margarite paragonite group mineral decreases and the proportion of ammonian illite increases from the sill to the roof the ca2 and k are more easily incorporated into the aluminosilicate mineral lattices than na and nh4 respectively thus the ca2 na ratio in the margarite paragonite group mineral decreases and the nh4 k ratio in the ammonian illite increases from the sill to the roof the formation of ankerite is also attributed to the igneous intrusion but this mineral was formed later than the aluminosilicate minerals the proportion of ankerite in the coal samples increases from the sill to the roof

kinetics of selenium release in mine waste from the meade peak phosphatic shale phosphoria formation wooley valley idaho usa abstract phosphorite from the meade peak phosphatic shale member of the permian phosphoria formation has been mined in southeastern idaho since 1906 dumps of waste rock from mining operations contain high concentrations of se which readily leach into nearby streams and wetlands while the most common mineralogical residence of se in the phosphatic shale is elemental se se 0 se is also an integral component of sulfide phases pyrite sphalerite and vaesite pyrite ss in the waste rock it may also be present as adsorbed selenate and or selenite and fese 2 and organo selenides se release from the waste rock has been observed in field and laboratory experiments release rates calculated from waste rock dump and column leachate solutions describe the net overall se release from all of the possible sources of se listed above in field studies se concentration in seepage water ph 7 4 7 8 from the wooley valley unit 4 dump ranges from 3600 g l in may to 10 g l by sept surface water flow q from the seep also declines over the summer from 2 l s in may to 0 03 l s in sept se flux se q reaches a steady state of q se release mg l follows a first order reaction with a rate constant k 1 35 6 35e 3 h 1 11 8 55 6 yr 1 laboratory experiments were performed with the waste shale in packed bed reactors residence time varied from 0 09 to 400 h and outlet ph 7 5 here se concentration increased with increasing residence time and release was modeled with a first order reaction with k 2 19e 3 h 1 19 2 yr 1 rate constants reported here fall within an order of magnitude of reported rate constants for oxidation of se 0 formed by bacterial precipitation this similarity among rate constants from both field and laboratory studies combined with the direct observation of se 0 in waste shales of the phosphoria formation suggests that oxidation of se 0 may control steady state se concentration in water draining the wooley valley waste dump

development of the east asian monsoon mineralogical and sedimentologic records in the northern south china sea since 20 ma we here reconstruct the past change of the east asian monsoon since 20 ma using samples from ocean drilling program odp site 1146 in the northern south china sea based on a multi proxy approach including a monomineralic quartz isolation procedure identification of clay minerals by x ray diffraction xrd and grain size analysis of isolated terrigenous materials terrigenous supply to odp site 1146 was dominated by changes in the strength of multiple sources and transport processes grain size data modeled by an end member modeling algorithm indicate that eolian dust from the and asian inland and fluvial input have contributed on average 20 and 80 of total terrigenous material to odp site 1146 respectively specifically about 40 53 of the total quartz feldspar and only 6 11 of the total clay is related to eolian supply at the study site detailed analysis of the sedimentary environment and clay minerals combined with previous studies shows that smectite originates mainly from luzon kaolinite from the pearl river and illite and chlorite from the pearl river taiwan and or the yangtze river the proportion and mass accumulation rate mar of the coarsest end member em1 interpreted as eolian dust ratios of illite chlorite smectite quartz feldspar and mean grain size of terrigenous materials at odp site 1146 were adopted as proxies for east asian monsoon evolution the consistent variation of these independent proxies since 20 ma shows three profound shifts in the intensity of east asian winter monsoon relative to summer monsoon as well as aridity of the asian continent occurred at similar to 15 ma similar to 8 ma and the youngest at about 3 ma in comparison the summer monsoon intensified contemporaneously with the winter monsoon at 3 ma the phased uplift of the himalaya tibetan plateau may have played a significant role in strengthening the asian monsoon at similar to 15 ma 8 ma and 3 ma c 2007 elsevier b v all rights reserved

a combined chemical isotopic and microstructural study of pyrite from roll front uranium deposits lake eyre basin south australia abstract the common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at pepegoona pepegoona west and pannikan lake eyre basin south australia combined chemical isotopic and microstructural analysis of pyrite indicates variation in fluid composition sulfur source and precipitation conditions during a protracted mineralization event the results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low temperature hydrothermal systems in situ micrometer scale sulfur isotope analyses of pyrite demonstrated broad scale isotopic heterogeneity 34 s 43 9 to 32 4 vcdt indicative of complex multi faceted pyrite evolution and sulfur derived from more than a single source preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation authigenic pyrite underwent prolonged evolution and recrystallization evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra secondary hydrothermal pyrite commonly displays hyper enrichment of several trace elements mn co ni as se mo sb w and tl in ore bearing horizons hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types irregular variation in 34 s coupled with oscillatory trace element zonation in secondary pyrite is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization a late stage oxidizing fluid may have mobilized selenium from pre existing pyrite subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re crystallization and precipitation of selenium as native selenium these results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at beverley north insights into depositional conditions and sources of both sulfide and uranium mineralization and an improved understanding of pyrite geochemistry can also underpin an effective vector for uranium exploration at beverley north and other sedimentary systems of the lake eyre basin as well as in comparable geological environments elsewhere

deciphering basaltic magmatism on the moon from the compositional variations in the apollo 15 very low ti picritic magmas picritic glass beads of volcanic origin have been interpreted as representing extremely primitive lunar magmas that approach primary magma compositions based on this they have been used for developing models for lunar magmatism estimating the mineralogical and chemical characteristics of their mantle sources constraining the dynamics and structure of the lunar mantle developing models for lunar core formation reconstructing the bulk composition of the moon and evaluating the genetic relationships between the earth and the moon yet we still do not truly understand many aspects of the compositional diversity among individual glass types or even within a single glass type using high precision ion microprobe techniques we have analyzed a total of forty very low ti glass beads from the apollo 15 a15 site and twenty additional picritic glass beads from other sampling sites for a suite of highly compatible ni co weakly compatible to weakly incompatible mn cr v and highly incompatible ce ti zr nb elements within the a15 very low ti glass population ni and co concentrations are positively correlated exhibit limited fractionation of ni co and are distinctive for individual glass groups as defined by major elements manganese is also colinear with both ni and co the highly incompatible elements also appear to be generally colinear with ni co and mn although there are distinguishable compositional offsets in the glass populations the ni co ratio does not differ dramatically among the very low ti glasses from other sampling sites although incompatible element concentrations may differ significantly these trace element data eliminate fractional crystallization and partial melting of a homogeneous source under extremely low fostaggered2 conditions as possible models for the origin of the compositional variations observed in the a15 very low ti glass population these data are consistent with the generation of these magmas through partial melting of a spatially restricted heterogeneous lunar magma ocean lmo cumulate sequence the compositional variation in these magmas can be produced by at least two different melting processes 1 partial melting of a cumulate sequence consisting of relatively early cumulates with a higher proportion of an intercumulus melt component green glass a d e and later cumulates with lower proportions of an intercumulus melt component green glass c 2 different degrees of partial melting of a cumulate sequence small degrees of partial melting less than 5 of a more primitive cumulate mantle source will generate one group of magmas green a d e whereas a group of other picritic magmas green c were produced by larger degrees of partial melting 10 to 20 of a mineralogically similar but a more evolved cumulate mantle source in both models the green b glass group is formed by either cumulate commingling or magma mixing processes these magmas cannot be rapidly transported from the source region to the lunar surface in a single eruptive event without extensive fractional crystallization yet the colinear relationship among ni co and mn is not compatible with extensive and variable fractional crystallization therefore a polybaric melting model as suggested by longhi 1992b appears to be the only alternative to producing relatively unfractionated apollo 15 very low ti picritic magmas with high pressure signatures the trace element data provides additional constrains for this type of model

selenium distribution and mode of occurrence in the kanawha formation southern west virginia u s a abstract selenium concentrations were measured in five rock cores from a mine in boone county west virginia to determine their relationship to sulfur rock type and stratigraphic location the samples spanned the winifrede and coalburg coal beds of the middle pennsylvania upper kanawha formation and included coals and clastic lithologies the coals generally contained the highest concentrations of se and the sandstones the lowest no correlation was observed between total se and sulfur concentrations for either the entire data set or for individual lithologies better correlations were identified for log concentrations between total se and total organic carbon principal component analysis identified a strong sulfur acid component interpreted to be due to sulfide mineral presence which correlates well with s but not with se coal sample chemistry is more likely to load onto this component while clastic rock chemistry is more likely to load onto the second non sulfur component se concentrations load onto both components indicating they are not controlled by a single overriding chemistry selective extractions indicate that se is distributed between both sulfide and organically bound fractions as defined by the test overall the lack of correlation between se and s the distribution of se among extracted fractions and the loading of se onto both sulfur and non sulfur components support that the se in these rock layers is distributed in more than one chemically bound form non coal rock units with the highest concentrations of se were found adjacent to coal beds suggesting that redistribution of se may have occurred post deposition the acidic domed swamps that formed these coals were low in sulfur and a reasonable chemical setting to accumulate se if it were introduced the preservation of se in the domed swamp peat coupled with post depositional redistribution may partly explain the data presented

volatile and siderophile element geochemistry of the moon a reappraisal abstract lunar volcanic glasses lvg contain high abundances of many volatile elements as compared to mare basalts whereas the latter were derived from devolatilized source regions in the outer few hundred kilometers of the moon lvg are believed to come from a globally extensive source region at greater depths which is relatively rich in volatile components abundances of volatile elements in lvg and their source regions are reviewed and in many cases found to resemble those in the earth s mantle likewise siderophile element abundances including the highly siderophile elements ir os au and re are similar in the earth s mantle and in the source regions of lvg the close geochemical similarity between the lvg source region i e the lunar lower mantle and the terrestrial mantle constitutes strong evidence that protolunar material was derived primarily from the earth s mantle since highly siderophile elements are believed to have been added to the earth as an oxidised veneer at the end of its accretion and then convectively mixed into the mantle the removal of protolunar material from the earth must have occurred after this late addition which may represent carbonaceous chondritic or cometary material from the outer solar system it is widely believed that the moon was formed by the impact of a giant planetesimal on the protoearth the planetesimal is presumed to have formed in the inner solar system and to have differentiated internally into a mantle and core numerical modelling of the giant impact shows that most of the material now in the moon would have been derived from the mantle of the impactor however this is contradicted by the geochemical evidence provided by lvg which implies that the moon is composed mainly of material derived from the terrestrial mantle a possible answer to this dilemma is provided by the observation that the lvg source region reflects the geochemistry of the late oxidised veneer which accreted on the earth this suggests that protolunar material may have been removed from the earth s mantle by impacts from one or more high velocity 30 km s planetesimals composed mainly of ices and derived from the outer solar system the volatiles from the impacting planetesimals were lost after these collisions the impacts probably ejected material from the earth s mantle as jets of molten matter which was rapidly quenched thereby retaining a large proportion of its terrestrial volatile inventory

the continent ocean transition at the southeastern margin of the south china sea abstract the south china sea formed by magma poor or intermediate volcanic rifting in the paleogene we investigate the structure of the continent ocean transition cot at its southern margin off nw palawan between the continental blocks of reed bank and the islands of palawan and calamian several surveys recorded by the bgr from 1979 to 2008 established a comprehensive database of regional seismic lines accompanied with magnetic and gravity profiles we interpret two major rifted basins extending in the ne direction across the shelf and slope separated by a structural high of non volcanic origin the continent ocean transition is interpreted at the seaward limit of the continental crust when magnetic spreading anomalies terminate some 80 100 km farther north the area in between displays extensive volcanism as manifest by extrusions that occasionally reach and cut the seafloor by dykes and by presumed basaltic lava flows occurring after break up the cot is highly variable along the nw palawan slope one type shows a distinct outer ridge at the cot with a steep modern seafloor relief the other type is characterised by rotated fault blocks bounded by listric normal faults ramping down to a common detachment surface half grabens developed above a strongly eroded pre rift basement the seafloor relief is smooth across this other type of cot we suggest the pre rift lithospheric configuration had major influence on the formation of the cot besides transfer zones volcanic domains confined to the north of competent crustal blocks correlate with the style of the cot gravity modelling revealed an extremely thinned crust across the shelf we propose a depth dependent extension model with crust being decoupled from mantle lithosphere explaining the discrepancy of subsidence observed across the south china sea region

ferromagnetic resonance intensity a rapid method for determining lunar glass bead origin ferromagnetic resonance intensity is was tested as a criterion for use as a nondestructive reliable and rapid screening method for distinguishing volcanic from impact glass spherules in the lunar soils this method relies on the absence or presence of single domain fe formed during impact melting by autoreduction of fe2 in the melt extensive scanning electron microscope sem inspection of individual glass bead surfaces provided reliable evidence of the mode of glass genesis ferromagnetic resonance intensity was tested against the type apollo 15 and apollo 17 volcanics additional volcanics were also found during the course of the study ninety four percent of the volcanic glasses had is values less than one implying the absence of single domain fe seventy five percent of impact glasses had elevated is values the remaining impact beads had is values less than one these samples lack single domain fe and could represent impact melts of bedrock with little or no regolith contribution the ability to discriminate bedrock derived impact melts as opposed to impact melts partially or completely derived from regolith and the primary discrimination of volcanic glasses from impact glasses suggests the fmr technique can be important in determining the origin of lunar glass spheres

experimental investigation of the partitioning of phosphorus between metal and silicate phases implications for the earth moon and eucrite parent body abstract the solid metal silicate melt partition coefficient for p d p has been determined experimentally at 1190 c and 1300 c the dependence of the partition coefficient on oxygen fugacity has been investigated and is consistent with a valence state of 5 for p in the silicate melt the experimental partition coefficients are given by log d p 1 21 log o 2 15 95 at 1190 c log d p 1 53 log o 2 17 73 at 1300 c the experimentally determined partition coefficients may be used to interpret the low p la ratios of the earth moon and eucrites relative to c1 chondrites the low p la ratios in the eucrites may be explained by partitioning of p into 5 to 25 of a sulfur bearing metallic liquid assuming equilibration and separation of the liquid metal from the silicates at low degrees of partial melting of the silicates the low w la ratios in the eucrites compared to c1 chondrites require the separation of an additional 2 to 10 solid metal the lowering of both p la and w la ratios in the moon may be explained by partitioning of p and w into metal during formation of a small core by separation of liquid metal from silicate at low degrees of partial melting of the silicates the w la ratios in the earth and moon are virtually indistinguishable while p la ratios differ by a factor of two the concentrations of feo also appear to be different these observations are difficult to reconcile with the hypothesis of a terrestrial origin of the moon following formation of the earth s core but are consistent with independent formation of the earth and moon

the occurrence and origin of selenium minerals in se rich stone coals spoils and their adjacent soils in yutangba china abstract several se bearing minerals have been identified in se rich stone coal spoils and their adjacent organic rich soils in yutangba of enshi china where human se toxicity occurred in the 1960s these minerals mainly include native se se 0 krutaite cuse 2 klockmannite cuse mandarinoite fe 2 seo 3 3 6h 2 o se bearing chalcopyrite cufe se s 2 and pyrite fe se s 2 the assemblage of native se krutaite klockmannite and se bearing pyrite and chalcopyrite is primarily present in the stone coal near a fault plane while the assemblage of native se and krutaite is found in the se rich carbonaceous mudstone and organic rich soils which are 60 m away from the stone coal exposure the assemblage of mandarinoite and native se is present in abandoned stone coal spoils where natural combustion occurred native se is quite extensive in the stone coal spoils and nearby soils derived from them the co occurrence of cu se minerals and native se indicates that these minerals could have formed under a relatively acidic and reducing environment below 220 c and suggests that cu could play a significant role in fixing reduced se ions in the acidic organic rich surface environment furthermore the occurrence of mandarinoite suggests that iron oxides constrain the geochemical behavior of se in oxidizing environments our observations provide new insights into the mechanisms of se fixation and accumulation during weathering of se rich rocks

plio pleistocene evolution of the var deep sea fan off the french riviera abstract the var deep sea fan was deposited during the pliocene and quaternary seaward progradation of the var delta within a steep sided flat floored basin formed during the messinian salinity crisis the prominent palaeo var canyon was cut on the slope at the same time following the early pliocene transgression var sediments were initially trapped in the coastal ria formed by sea level incursion of the head of the messinian valley by middle pliocene time gilbert type deltas had prograded to the break of slope modern coastline allowing coarse sediment to reach the basin quaternary coastal uplift and sediment supply from the glaciated alps resulted in a supply of coarse sediment to the fan by the braided var river throughout the quaternary even during sea level highstands such as the present in the earliest pliocene hemipelagic clays accumulated while coarse sediment was trapped in the var ria through the rest of the pliocene a leveed fan valley extended southward from the var canyon which periodically switched locations through avulsion to the east at about the beginning of the quaternary this eastward spillover channel became the main distributary and re occupation of the older south trending channels was blocked by rapid levee progradation and aggradation of mud waves by overbanking of turbidity flows on the var sedimentary ridge during the quaternary channel shifting to the north occurred the quaternary var fan has an unusually steep concave longitudinal profile compared with most passive margin fans the laurentian fan has a similar profile to the var both have a high levee and a gravel and pebble floored fan valley that is essentially a bypass zone compared with the aggradational channel levee systems with lower levees in most passive margin fans this is a consequence of the constant supply of coarse sand gravel and pebbles to the fan even during highstands of sea level the erosive capability of this coarse sediment in ignitive turbidity currents resulted in flushing out of the upper and middle fan valley system thick muddy turbidity currents probably resulting from slumping caused by canyon incision produced the prominent mud waves on the levee the concave longitudinal profile led to rapid sediment deposition at critical points in the valley system as a result of turbidity flow expansion this in turn promoted the development of a left hook in the valley system

remote sensing of lunar pyroclastic mantling deposits abstract mantling deposits on the moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining these pyroclastic units are characterized as having low albedos having smooth fine textured surfaces and consisting in part of homogeneous febearing volcanic glass and partially crystallized spheres mantling units exhibit low returns on depolarized 3 8 cm radar maps indicating an absence of surface scatterers in the 1 to 50 cm size range a number of reflectance spectra from several regional pyroclastic deposits are presented for the first time these data support a previous interpretation that mantling units have a unique spectral signature which is indicative of the presence of a significant fe bearing volcanic glass component the rima bode region is discussed as an example of an area in which several types of remote sensing data including 3 8 cm radar spectral reflectance and multispectral vidicon data were used to reconstruct the geologic events surrounding the emplacement of a regional pyroclastic mantling deposit the recognition of numerous varieties of volcanic glass samples especially relatively high albedo e g green yellow glasses suggests the existence of additional unrecognized mantling deposits with albedos higher than those studied to date on the basis of the remote sensing data summarized and presented five new areas have been identified which may represent higher albedo regional pyroclastic deposits

shelf margin architecture variability and its role in sediment budget partitioning into deep water areas abstract a review of 127 shelf margin accretion segments from 24 margins worldwide suggests that sediment flux can be low or high that shelf accommodation can be low medium or high and that climatic conditions can be icehouse or greenhouse the interplay of these three variables yields four main greenhouse margins and six main icehouse margins and thus has a fundamental control on shelf margin architectural styles providing new tools for predicting internal architecture of deep water systems in greenhouse settings there is commonly a strong supply drive because of higher temperatures more variable precipitation and higher sediment discharge but only modest shelf accommodation because of low frequency and low amplitude eustatic sea level changes low shelf accommodation is able to deliver significant volumes of sand sourced from either low or high sediment supply areas to deep water environments and residence time for deltas at greenhouse margins is likely to be relatively long because of the low amplitude of greenhouse sea level changes medium accommodation in contrast may overwhelm any low sediment supply but could be partly overwhelmed by high sediment supply which in turn can inhibit fans or encourage highstand fans in icehouse settings there is a strong cross shelf accommodation drive created by high frequency and high amplitude eustatic sea level changes thus causing significant and frequently repeated transits of river mouths and deltas across the shelf sandy basin floor fans created by low accommodation are predicted with either high or low sediment flux both medium and high accommodation can be volumetrically overwhelmed by high sediment supply which in turn cause greater volumes of sediment storage on the shelf resulting in volumetrically less significant highstand or transgressive submarine fans however a low supply may barely allow deltas to reach the shelf edge causing the deep water areas to be dominantly muddy

assumptions about the presence of natural glasses on mars natural glasses occur not only on earth but also in lunar rocks and in some meteorites on geological grounds natural glasses could be expected on the surface of mars and their presence would have important implications for the weathering and alteration of the near surface layer ultramafic and mafic magmatism rich in iron and some volatiles appears to have been important on mars as has been impact cratering volcanism and possibly hydrothermal alteration available data indicate that we can presume the past or present existence of volcanic basaltic glasses impact glasses formed by thermal fusion of meteorite impact targets and diaplectic mainly maskelynite glasses conditions appear unsuitable for the formation of tektites on the martian surface and the production of measurable amounts of fulgurite or combustion glass seems improbable prospects for the remote and in situ identification of martian glasses and their subsequent weathering products are discussed and include orbital reflectance and thermal emission spectroscopic measurements and mossbauer spectroscopy from a surface lander

shelf edge delta regime as a predictor of deep water deposition abstract shelf edge delta depositional style and particularly the presence of river dominated shelf edge deltas is a reliable indicator of deep water sand delivery as documented by a dataset of some 29 shelf margin clinoforms shelf edge delta regime defined as the sum of the effects of fluvial tidal wave and other oceanographic currents impacting deltas as they arrive at the shelf edge is a key predictor for likelihood of sand transport off the shelf edge to deep water conventional sequence stratigraphic concepts assume that delivery of sand to the deep water occurs primarily during falling and lowstand of relative sea level and that basinward transport is associated with shelf edge incision and sediment bypass recent analysis of outcrop and subsurface datasets has shown that sediment can also be transported to the deep water during rising and highstand of sea level provided sediment flux is high in addition some examples with documented shelf edge entrenchment associated with sea level fall did not deliver significant sand volumes to the deep water in contrast to the emphasis given to sea level and supply the role of the shelf edge delta itself and especially its process regime has received relatively little attention the data suggest that the behavior and process regime of the delta at the shelf edge is critical except where shelf width is minimal

paleocene wilcox cross shelf channel belt history and shelf margin growth key to gulf of mexico sediment delivery abstract shelf margins prograde and aggrade by the incremental addition of deltaic sediments supplied from river channel belts and by stored shoreline sediment this paper documents the shelf edge trajectory and coeval channel belts for a segment of paleocene lower wilcox group in the northern gulf of mexico based on 400 wireline logs and 300 m of whole cores by quantitatively analyzing these data and comparing them with global databases we demonstrate how varying sediment supply impacted the wilcox shelf margin growth and deep water sediment dispersal under greenhouse eustatic conditions the coastal plain to marine topset and uppermost continental slope succession of the lower wilcox shelf margin sediment prism is divided into eighteen high frequency 300 ky duration stratigraphic sequences and further grouped into 5 sequence sets labeled as a e from bottom to top sequence set a is dominantly muddy slope deposits the shelf edge of sequence sets b and c prograded rapidly 10 km ma and aggraded modestly 80 m ma characterizes sequence sets d and e which is associated with smaller 9 10 m thick on average and isolated channel belts this stratigraphic trend is likely due to an upward decreasing sediment supply indicated by the shelf edge progradation rate and channel size as well as an upward increasing shelf accommodation indicated by the shelf edge aggradation rate the rapid shelf edge progradation and large rivers in sequence sets b and c confirm earlier suggestions that it was the early phase of lower wilcox dispersal that brought the largest deep water sediment volumes into the gulf of mexico key factors in this lower wilcox stratigraphic trend are likely to have been a very high initial sediment flux to the gulf because of the high initial release of sediment from laramide catchments to the north and northwest possibly aided by modest eustatic sea level fall on the texas shelf which is suggested by the early flat shelf edge trajectory high amalgamation of channel belts and the low overall aggradation rate of the sequence sets b and c

geochemistry of the la erma and qiongmo au se deposits in the western qinling mountains china abstract the microdisseminated gold deposits at la erma and qiongmo are typically hosted in cambrian chert formation in western qinling mountains china both in the host rocks and the gold ores selenium is present in high abundance as selenide minerals or isomorphous admixtures in sulfides with independent selenium orebodies can be delineated in some localities intergrowth of selenides and native gold is commonly observed selenium is also noticed in considerably high content in fluid inclusions in quartz and barite which are closely related to gold mineralization studies show that gold and selenium may have been transported together in ore solutions as au s se complex in view of the wide difference in electrode potential between selenium and sulfur the two elements would be separated under oxidizing conditions selenium would mostly occur as isomorphic mixtures in sulfides during the early stage of mineralization when the environment is more reducing but would precipitate as selenides during the late oxidizing stage simultaneous enrichment of gold and selenium would be favored by boiling of the ore solution or mixing of ore solution with oxygen rich water at shallow depths

supergene sulphides and related minerals in the supergene profiles of vhms deposits from the south urals abstract the mineralogy and structure of the supergene profile in recently exploited volcani hosted massive sulphide vhms deposits of cyprus uralian and kuroko type in the south urals russia have been studied specific subzones enriched in secondary sulphides and associated minerals have been distinguished in residual pyrite and quartz pyrite sands at the gayskoye zapadno ozernoye dzhusinskoye and alexandrinskoye deposits besides minerals which are common to the cementation subzones covellite chalcocite and acanthite non stoichiometric colloform and framboidal pyrite pyrite dzharkenite pyrrhotite like and jordanite like minerals metacinnabar sphalerite selenium enriched tetrahedrite and unidentified as sb sulphosalts of pb or hg and ag sulphur bearing clausthalite naumannite and tiemannite were also found secondary sulphide minerals in vhms deposits of the south urals region are characterized by light sulphur isotope compositions 8 1 to 17 2 superposition of the advanced oxidation of colloform pyrite an enrichment in impurities sphalerite galena and tennantite from the primary ores stagnant water conditions an elevation of the water table during oxidation and bacterial activity led to supergene concentrations of the base metals as sulphide selenides or sulphosalts

39ar 40ar ages for the apollo 15 green and yellow volcanic glasses a technique using the laser microprobe to extract noble gases from individual small 100 750 m in diameter low potassium 0 09 wt k2o glassy samples was developed this technique has an advantage in that an individual sample can be chemically characterized by an electron microprobe and then analyzed for its argon age thus eliminating any ambiguities in the classification of the sample and the need for large quantities of samples this technique was then used to study the argon isotopes and apparent 39ar 40ar ages of three varieties of volcanic glass from apollo 15 yellow volcanic green volcanic group a and green volcanic group d the apparent solidification age for the glasses are 3 62 0 07 3 41 0 12 and 3 35 0 18 aeons respectively the ages for group a and d green glasses agree well with previously reported ages for aliquots of bulk green glass a value of 40ar 36arsw 0 5 0 5 was used to correct the data since a 40ar 36arsw versus 39ark 36arsw plot failed to identify a well defined trapped component no significant difference in the solidification age 0 2 aeons was found between the a and d groups of the volcanic green glasses these ages for volcanic glasses are consistent with the prediction of delano and livi 1981 that array ii volcanic glasses are generally older 3 6 aeons than array i glasses the average exposure ages for the apollo 15 yellow volcanic and green volcanic groups a and d glasses from 15426 and 15427 were indistinguishable with ages between 300 and 275 m y

the la ce geochronometer a new dating method the isotope 138la 0 089 of natural lanthanum decays by and electron capture to 138ce and 138ba with a long half life we present here the first age determination using la ce dating an internal la ce isochron of a gabbro from the upper zone of the bushveld south africa yields an age of 2 390 480 2 myr based on the partial decay constant 2 58 10 12 yr 1 this age agrees with the sm nd isochron age 2 050 90 2 myr which was obtained from an aliquot of the same sample solution within the uncertainties of 138la half life and isotopic measurement

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