a kinematic model for recrystallization and texture development in olivine polycrystals the interpretation of seismic anisotropy in the mantle requires a knowledge of the relationship between the lattice preferred orientation lpo of crystals and the convective flow field in order better to understand this link we present a model for the evolution of lpo in olivine aggregates that deform by both intracrystalline slip and dynamic recrystallization dynamic recrystallization depends on the dislocation density of the grains which is a function of the applied local stress grains with a large density of dislocations lower their bulk strain energy by nucleating strain free sub grains at a rate proportional to a dimensionless nucleation parameter grains with high energy are then invaded by grains with low energy by grain boundary migration at a rate proportional to a dimensionless grain boundary mobility m the value of is constrained by observed lpo patterns in experimentally deformed olivine aggregates and m is constrained by the temporal evolution of the strength of the lpo for m 125 75 and 3 the model predictions agree well with the experimental results numerical calculations of lpo using our model are significantly faster than those based on viscoplastic self consistent or equilibrium based theories making the model especially suitable for applications for complex convective flows

lithologic succession in the path fork coal bed breathitt formation middle pennsylvanian southeastern kentucky abstract the path fork coal bed breathitt formation middle pennsylvanian westphalian b on the pine mountain thrust sheet in southeastern kentucky and adjacent portions of virginia exhibits a lithologic succession which is traceable for about 25 km lateral continuity of lithotypes within the bed can be demonstrated using organic petrography palynology and ash geochemistry the lithologic continuity is a consequence of the initial levelling of the pre peat topography and the interaction of the peat with growing anticlines and synclines

modeling dynamic recrystallization of olivine aggregates deformed in simple shear experiments by zhang and karato 1995 have shown that in simple shear dislocation creep of olivine at low strains an asymmetric texture develops with a 100 maximum rotated away from the shear direction against the sense of shear at large strain where recrystallization is pervasive the texture pattern is symmetrical and 100 is parallel to the shear direction the deformation texture can be adequately modeled with a viscoplastic self consistent polycrystal plasticity theory this model can be expanded to include recrystallization treating the process as a balance of boundary migration growth of relatively underformed grains at the expense of highly deformed grains and nucleation strain free nuclei replacing highly deformed grains if nucleation dominates over growth the model predicts a change from the asymmetric to the symmetric texture as recrystallization proceeds and stabilization in the easy slip orientation for the dominant 010 100 slip system this result is in accordance with the experiments and suggests that the most highly deformed orientation components dominate the recrystallization texture the empirical model will be useful to simulate more adequately the development of anisotropy in the mantle where olivine is largely recrystallized

mantle flow in subduction systems the subslab flow field and implications for mantle dynamics 1 the character of the mantle flow field in subduction zones remains poorly understood despite its importance for our understanding of subduction dynamics in particular little attention has been paid to mantle flow beneath subducting slabs in order to identify processes that make first order contributions to the global pattern of subslab mantle flow we have compiled shear wave splitting measurements from subduction zones worldwide from previously published studies and estimated average splitting parameters for the subslab region globally the subslab region is overwhelmingly dominated by trench parallel fast splitting directions we tested for relationships between splitting delay time a measure of the strength of anisotropy and parameters that are indicators of tectonic processes such as trench migration velocity convergence velocity and obliquity age of subducting lithosphere and slab dip curvature seismicity and thickness we used several different plate motion models to describe plate and trench motions and evaluated the differences among the models we find that only one parameter namely the trench migration velocity in a pacific hot spot reference frame appears to correlate well with the strength of the subslab splitting signal this finding supports a model in which the mantle beneath subducting slabs is dominated by three dimensional flow induced by trench migration we explore several implications of our model for various aspects of mantle dynamics including the choice of a suitable reference frame s for mantle flow the existence of a thin decoupling zone between slabs and the subslab mantle and consequences for mass transfer between the upper and lower mantle

origin of minerals and elements in the late permian coals tonsteins and host rocks of the xinde mine xuanwei eastern yunnan china abstract this paper reports the mineralogical and geochemical compositions of the late permian c2 and c3 coals both medium volatile bituminous coal from the xinde mine near xuanwei in eastern yunnan which is located close to the area with the highest female lung cancer mortality in china the two coals are characterized by high ash yields and low sulfur contents three factors including sediment source region multi stage volcanic ash generation and multi stage hydrothermal fluid injections were responsible for variations in the geochemical and mineralogical compositions of the xinde coals trace elements including v sc co ni cu zn se zr nb hf and ta are enriched in the coals and were mainly derived from the sediment source kangdian upland region major minerals in the samples of coal roof floor and non coal sediment partings include quartz kaolinite and chamosite as well as interstratified illite smectite and anatase chamosite in the coal was derived from reactions between kaolinite and fe mg rich hydrothermal fluids however chamosite in the roof strata was directly precipitated from fe mg rich hydrothermal fluids or was derived from the alteration of precursor minerals e g biotite by hydrothermal fluids quartz in some samples is very high especially in the roof strata of the c2 and c3 coal such high quartz along with minor minerals including pyrite chalcopyrite sphalerite calcite celestite vanadinite barite clausthalite and silicorhabdophane were derived from multi stage hydrothermal fluids the floors of both the c2 and c3 coal seams are fully argillized fine grained tuffaceous claystone and the immediate roof of the c2 coal is argillized coarse grained tuff the original materials of the floors and roofs of these coal seams were high ti alkali basaltic volcanic ashes as indicated by high tio 2 nb and siderophile elements and the distribution patterns of rare earth elements two intra seam tonstein layers in the c3 coal were identified based on their lateral persistence mineralogical mode of occurrence and composition as well as their elemental composition the tonsteins are dominated by kaolinite with minor quartz and possibly mixed layer illite smectite both tonsteins were derived from dacitic magma the ratios of nb ta zr hf and u th are much lower in tonsteins than in the adjacent coal benches which is attributed to the hydrothermal leaching

lpo predicted seismic anisotropy beneath a simple model of a mid ocean ridge 1 modelling of seismic anisotropy in complex geodynamic environments is common however the sensitivity of predicted seismic anisotropy and shear wave splitting to mineral parameters is sometimes overlooked we use a simple ocean ridge corner flow solution to investigate the effect of varying mineral parameters on the generation of seismic anisotropy and whether these differences can be detected by the predicted shear wave splitting we find that seismic anisotropy and shear wave splitting predicted using lpo theory is sensitive to mineral input parameters such as grain boundary mobility grain boundary sliding and mineral composition however experimental constraints greatly reduce the range of predicted values predicted shear wave splitting for a range of mineral parameters are consistent with observations at mid ocean ridges although differences are seen in the predicted shear splitting for different mineral parameters they are probably too small to detect in observations and hence will not give us new insights in to variation in mantle mineral properties

advances in velocity model building technology for subsalt imaging seismic imaging of hydrocarbon accumulations below salt is a formidable challenge because complexly shaped salt bodies severely distort wavefronts or scatter seismic energy we have highlighted some recent advances in building a velocity model for subsalt imaging there are three main stages suprasalt velocity determination salt model definition and subsalt velocity update volumetric high resolution tomography that incorporates high velocity contrast boundaries is used to derive a good sediment velocity model before building a salt model to facilitate integration of interpretation and depth processing beam based interactive imaging is used to refine the salt geometry for subsalt velocity update either subsalt tomography or subsalt scan based techniques can be used depending on the quality of subsalt reflections there are concepts and techniques for attaining subsalt images suitable for hydrocarbon exploration beneath complexly shaped salt bodies

rare earth element patterns a tool for identifying trace metal sources during wetland soil reduction abstract in wetland soils several soil phases such as fe iii oxyhydroxides organic matter om or mixed fe om particles can host trace metals which can be subsequently released during soil reduction anoxic and oxic wetland soil incubation experiments combined with analyses of soil solutions sampled from a natural wetland during a reduction event are used to test the possibility that rare earth elements ree could be used as a tool to identify the soil phases contributing to trace metal solubilization significant amounts of trace metals cu cr co ni and pb and ree are released during anoxic incubation of the wetland soil concomitantly with the build up of high concentrations of fe ii and dissolved organic matter dom rare earth element patterns obtained in the soil solution exhibit a middle rare earth elements mree downward concavity the ree pattern obtained from field samples yields the same feature as developed in the soil solution from an oxic incubation experiment at ph 7 designed to promote soil om desorption by contrast significantly different ree patterns are obtained in incubation experiments designed to promote chemical reduction of fe oxyhydroxides in soils the ree pattern displays a continuous ree enrichment from la to lu these distinct and recognizable ree signatures allow us to conclude that i soil organic matter is the main source of ree and trace metals during wetland soil reduction ii fe ii is provided by the reduction of amorphous fe iii nanoparticles embedded within the organic matter which do not bind ree or other trace metals in significant proportions ree and trace elements being preferentially complexed to organic matter and finally iii ree provide a reliable and powerful tool suitable for identifying trace metal sources during wetland soil reduction

distribution of rare earth elements in eastern kentucky coals indicators of multiple modes of enrichment abstract four eastern kentucky pennsylvanian coals from oldest to youngest the manchester pond creek fire clay and hazard coals were examined for their total rare earth element rey concentration and the possible mechanisms for enrichment of the rare earths based on previous studies four possible modes are considered terrigenous tuffaceous infiltrational and hydrothermal with the dean coal a correlative of the fire clay coal considered to be a typical example of the tuffaceous mode the fire clay owes much of its high rey content to the presence of a volcanic ash fall tonstein with rey bearing zircon and phosphates in the coal in numerous locations some of the original rey elements may have components of the detrital minerals deposited in the peat leaching of rey from the tonstein into the surrounding coal and the hydrothermal overprint of mineralizing fluids associated with the northwestwardly movement of the pine mountain thrust sheet contributed to the total rey signature in the fire clay coal not all coals are going to have the complex history of the fire clay coal but it should be considered that the total history of rey enrichment by multiple mechanisms is what gives us both the total rey concentration and the relative distribution of the individual lanthanide elements

revisiting the late permian coal from the huayingshan sichuan southwestern china enrichment and occurrence modes of minerals and trace elements abstract the late permian coals from the huayingshan coalfield of southwestern china are significantly enriched in zr 695 g g nb 75 9 g g se 6 99 g g hf 10 1 g g and rare earth elements and y 1423 g g previous studies showed that the sediment source region for these coals was the kangdian upland which was formed at an early stage of the late permian period the source rocks have a basalt composition and those studies attributed the enrichment of the above high field strength elements hfses to derivation from the kangdian upland geochemical and mineralogical data presented in this study show that the dominant sediment source regions for the coal and roof strata of the huayingshan coalfields are the dabashan uplift hannan upland and leshan longnvsi uplift the highly elevated concentrations of hfses in the coals are due to hydrothermal fluids three tonstein layers derived from alkali rhyolite were identified these tonsteins are characterized by highly enriched hfses and by strong negative eu anomalies in the rare earth element distribution patterns the major carriers of the rare earth elements in the coal are rhabdophane and silicorhabdophane the latter of which is also enriched in zr zirconium however mainly occurs in zircon rhabdophane and silicorhabdophane in the coal are mainly distributed along the bedding planes and occur as cell fillings zircon in the coal occurs as cell fillings and is of authigenic origin anatase in the partings and coals contains nb and occurs as fracture filling and colloidal forms the modes of occurrence of the above minerals indicate that they were derived from hydrothermal fluids mercury and se mainly occur in sulfide minerals pyrite and marcasite

current shortening across the himalayas of nepal summary underthrusting of the indian lithosphere beneath the himalayas occurs during the quaternary period along a gently north dipping main basal detachment main himalayan thrust mht from which the southernmost emergent ramp main frontal thrust mft branches historical seismicity shows that slip on the mht is frequently accommodated through m 8 shallow earthquakes but shows a seismic gap in western nepal this absence of major historical earthquakes in western nepal can be explained either by an aseismic slip on the mht or a longlived elastic strain accumulation to test these hypotheses the present day displacement field has been measured for a gps network formed of 35 sites the updated solution presented in this paper combines data from 1995 1997 1998 and 2000 measurements the lack of deformation less than 3 10 8 yr 1 through the outer belt does not fit with a regional aseismic slip along the southern part of mht a less than 3 mm yr 1 aseismic slip could nonetheless affect restricted areas of the outer belt in contrast a strain accumulation of more than 30 10 8 yr 1 is measured south of the higher himalayas in a zone where an intense microseismicity reflects a stress build up it is presumably generated by locking of the aseismic creep that occurs along the mht beneath the higher himalayas and tibet the displacement field is simulated by a dual dislocation model that takes into account the pattern of microseismicity and particularly a segmentation between central and western nepal the best fit between the measured and simulated displacement fields is obtained with 19 mm yr 1 thrust and 0 1 mm yr 1 dextral strike slip components along a 117 ne dislocation locked to a depth of 20 21 km beneath western nepal and 19 20 mm yr 1 thrust and 0 2 mm yr 1 dextral strike slip components along a 108 ne dislocation locked to a depth of 17 21 km beneath central nepal the width of the locked zone between the main frontal thrust and the creeping zone is of the same order but rather greater in western nepal than in central nepal therefore it is expected that m 8 earthquakes could occur in western nepal

geochemistry of the rare earth elements in hypersaline and dilute acidic natural terrestrial waters complexation behavior and middle rare earth element enrichments rare earth element ree speciation was modelled in acid 2 9 ph 3 5 hypersaline groundwaters from australia and from the palo duro basin in texas usa using a combined specific ion interaction pitzer model and ion pairing model the free metal ion species i e ln3 is the dominant form of dissolved rees in these systems accounting for 40 70 of the dissolved metal in groundwater from lake tyrrell victoria australia 50 90 of the rees in groundwater from lake gilmore western australia and always 90 of each ree in the texas groundwaters lakes tyrrell and gilmore are actually dry lakes that act as groundwater discharge zones the abundance of the free metal ion species increases in these waters with increasing ionic strength and with decreasing ph the free metal ion species is followed in abundance by ree sulfate and ree chloride complexes that account for 20 50 and 10 15 respectively of the dissolved rees in the groundwaters from lake tyrrell 15 30 and 5 20 respectively in the groundwaters from lake gilmore and 3 and 7 respectively in the palo duro basin groundwaters the groundwaters of the lake tyrrell system and the palo duro basin are enriched in the middle rees mrees compared to both the light rees lrees and the heavy rees hrees only nd sm and dy were determined in the lake gilmore groundwaters and consequently it is unclear whether these acid groundwaters are also enriched in the mrees previous investigators suggested that fe rich organic flocs ree phosphate complexation and solid liquid exchange reactions between terrestrial waters and mree enriched surface fe mn coatings suspended particulates or secondary mineral phases within aquifer materials may promote the development of mree enrichments in natural waters we propose that organic colloids and ree phosphate complexes are insignificant in acidic natural waters in regards to mree enrichments instead solid liquid exchange reactions or dissolution of surface coatings suspended particulates and or secondary phases as well as sulfate complexation more likely controls the development of mree enrichments in acidic natural terrestrial waters

mineralogical and geochemical anomalies of late permian coals from the fusui coalfield guangxi province southern china influences of terrigenous materials and hydrothermal fluids abstract the late permian coal in the fusui coalfield of southern china is characterized by high fe sulfide and organic sulfur contents 2 60 and 2 94 respectively trace elements including zr 354 g g on average hf 9 18 g g y and rare earth elements rey 302 g g li 97 9 g g and cs 7 02 g g are significantly enriched in these coals in addition to hg and se enrichment in the roof and floor of the coal fluorine mo and u are enriched in the roof the floor is rich in cl s fe pb and cd compared to the upper continental crust rey in the parting and coal bench samples are characterized by heavy rey and light rey enrichment respectively the coals partings and host rocks roof and floor have negative eu anomalies the coal benches have higher ratios of u th yb la nb ta and zr hf and more abundant heavy rare earth elements than their adjacent partings these geochemical anomalies are attributed to the composition of terrigenous materials derived from the yunkai upland multi stage syngenetic and epigenetic hydrothermal fluid activities and intensive leaching and re distribution of lithophile elements from partings to the underlying coal benches both the organic and sulfide sulfur are also derived mainly from the hydrothermal fluids rather than the marine influence the minerals in the samples studied including kaolinite quartz and ree bearing minerals are of both terrigenous and hydrothermal origin al oxyhydroxides crystalline feso 4 oh water bearing fe oxysulfate and goyazite were derived from the hydrothermal activity kaolinite quartz ree bearing minerals and apatite from the sediment source region were also subjected to destruction by hydrothermal fluid leaching

petrology mineralogy and geochemistry of the ge rich coal from the wulantuga ge ore deposit inner mongolia china new data and genetic implications abstract the early cretaceous wulantuga high ge coal deposit in inner mongolia is one of the major coal hosted ge deposits in china this paper reports new data on the petrological mineralogical and geochemical compositions of 13 bench samples of the high ge no 6 coal from the wulantuga deposit and provides new insight into the origin and modes of occurrence of the minerals and elements present the no 6 coal has a low rank ro max 0 45 and is a low ash coal 8 77 the total content of inertinite 52 5 vol on average in most coal benches is higher than that of huminite 46 8 vol on average the dominant huminite maceral is textinite averages 43 9 and the dominant inertinite macerals are mainly fusinite averages 33 and semifusinite 12 5 along with trace portions of intertodetrinite secretinite funginite and macrinite fungus seen as the maceral funginite played a role in the development of degraded maceral forms in the wulantuga coals funginite is present in samples examined in this study but is not easily extracted during palynological studies recovered fungal taxa are saprophytes indicating woody decomposition prior to incorporation in the mire palynology revealed a sparse flora that is consistent with the early cretaceous age minerals in the coal include quartz kaolinite illite and or illite smectite gypsum pyrite and traces of rutile and anatase a varying proportion of bassanite was observed in the low temperature ashes ltas bassanite in the ltas was derived both from the dehydration of gypsum in the raw coals and from the interaction between organically associated ca and s during the low temperature ashing in addition to a proportion of detrital quartz fine grained and cell filling quartz of authigenic origin is also present pyrite is of syngenetic origin and derived from sulfate rich hydrothermal fluids compared to common chinese and world low rank coals the no 6 coal is enriched in be 25 7 g g f 336 g g ge 274 g g as 499 g g sb 240 g g cs 5 29 g g w 115 g g hg 3 165 g g and tl 3 15 g g germanium in the coal is organically associated and its enrichment is attributed to hydrothermal fluids from the adjacent granitoids beryllium is probably associated with ca and mn bearing carbonate minerals and to a lesser extent with clay minerals rather than with organic matter fluorine largely occurs in clay minerals kaolinite and illite the elevated concentrations of tl hg as and sb are mainly distributed in pyrite and were derived from the same hydrothermal source the high w in the coal occurs in both the organic matter and the authigenic quartz illite is the major carrier of cs in the coal the accumulation of rare earth elements ree in the coals had a polygenetic and multistage nature including two syngenetic stages early hydrothermal and terrigenous and one diagenetic late hydrothermal stage the ree distribution patterns of the early hydrothermal and terrigenous stages were characterized by the enrichment of medium ree m type ree and light ree l type ree respectively a h type ree distribution pattern hree enrichment occurred in the late diagenetic hydrothermal stage the high ge wulantuga coals are also abnormally enriched in precious metals gold pt and pd in the coals calculated from their concentrations in the ltas are 3 5 25 8

coal rank trends in the central appalachian coalfield virginia west virginia and kentucky abstract coal rank determined from vitrinite maximum reflectance and from chemical rank parameters increases from high volatile c bituminous in portions of the eastern kentucky coalfield to low volatile bituminous in buchanan county virginia and mcdowell county west virginia and then decreases significantly to the dry fork anticline 20 km to the southeast the latter rank decrease as noted when rank data from individual coals is used across the fold 400 500 m structural relief can be accounted for by post tectonic coalification at a paleogeothermal gradient of about 40 45 c km reflectance gradients decrease from about 0 09 rmax 100 m in central buchanan county virginia to 0 06 rmax 100 min southeastern pike county kentucky to 0 03 max 100 m and less among the high volatile a and b coals to the nortwest of pike county the reflectance gradients are likely an indication of a decrease in paleogeothermal gradient to the northwest depth of burial may have also decreased to the northwest northward trending rank anomalies superimposed on the regional trend in kentucky may have been caused by subtle changes in the geothermal gradients associated with basement discontinuities or alternately by a depth of burial not accounted for at present perhaps under now eroded thrust sheets

an olivine fabric database an overview of upper mantle fabrics and seismic anisotropy we present a unique database of 110 olivine petrofabrics and their calculated seismic properties the samples come from a variety of the upper mantle geodynamic environments ophiolites subduction zones and kimberlites with a wide range of micro structures a phenomenological relationship is established between p and s wave seismic anisotropy and the degree of crystal alignment fabric strength seismic anisotropy increases rapidly at low fabric strength before reaching a near saturation level of 15 to 20 for p waves and 10 to 15 for s waves despite a large variation in the symmetry of fabric patterns the average seismic properties of the different fabric micro structural and geodynamic settings have similar anisotropies in both magnitude and symmetry hence it would seem possible to determine some measure of fabric strength from seismic anisotropy if the dimensions of the anisotropic region are known but not geodynamic environment or details of the petrofabric pattern a simple pattern of seismic anisotropy characterises the average sample of the database which has the following features the polarisation plane of the fastest s wave is parallel or sub parallel to the foliation plane the maximum shear wave splitting is parallel to the y structural direction in foliation plane and normal to the lineation the maximum of the p wave velocity is parallel to the high concentration of 100 axes which is sub parallel to the lineation the 100 orientation distribution has the greatest influence on the p wave seismic anisotropy the 100 and 001 orientation distributions have the greatest influence on the symmetry of s wave anisotropy although the magnitude of anisotropy is influenced by the distribution of all three principal axes although the database only contains olivine petrofabrics this statistical study clearly shows that seismic anisotropy can be used to deduce the orientation of the structural frame in the upper mantle 1998 elsevier science b v all rights reserved

seismic anisotropy of the upper mantle 1 factors that affect mineral texture and effective elastic properties 1 flow induced mineral alignment in the earth s mantle affects the nature of seismic wave propagation since measurements of seismic travel time and shear wave splitting are a key means by which the structure of the upper mantle can be imaged it is important to understand the factors that contribute to variability in elastic properties seismic anisotropy associated with lattice preferred orientations of minerals in peridotite is the focus of this study one way to better understand anisotropy in a convecting upper mantle is to simulate texture evolution based on certain assumptions simulations of the development of olivine and orthopyroxene alignment along streamlines of a mantle flow field illustrate how continuously varying strain conditions affect the resulting orientation distribution there are various uncertainties in rock texture simulations and the aim here is to investigate how much model assumptions may influence the results a model of upper mantle flow in the vicinity of an oceanic spreading center is used to illustrate these points first we assess how sensitive results are on assumptions of different polycrystal plasticity models specifically lower bounds and viscoplastic self consistent approaches we also investigate how recrystallization during deformation might affect the texture that develops along a streamline the effects of grain growth and nucleation produce as expected textures that are different from the deformation only case however the basic p wave structure of the predicted anisotropy is similar between models for streamlines in a slow spreading passive flow model as is commonly used for simulating flow near this type of plate boundary shear wave splitting patterns are more complex and differ somewhat more between the models in the off axis region we also compare predictions for texture development of olivine only aggregates to that of mixed composition with 70 olivine and 30 orthopyroxene although we consider only one aspect of such polyphase deformation i e plastic deformation on specified crystal slip systems our results are consistent with field observations of the orientation distributions in ophiolitic peridotites finally we determine how simplifying assumptions about the symmetry of the elastic anisotropy can bias interpretations of seismic travel time and shear wave splitting whereas a hexagonal approximation can lead to underestimates of the degree of anisotropy an orthorhombic approximation is found to closely match the results predicted for a general elastic tensor corresponding to an orientation distribution whose symmetry is as low as monoclinic or triclinic

the organic geochemistry of coal from plant materials to coal coalification is a process that transforms plant remains under the influence of time temperature and possibly pressure to a black generally lustrous solid organic fossil fuel having a very complex chemistry although much has been learned in the past two centuries on coal chemistry we still have little knowledge of the way plant materials undergo these transformations the problem has been the existence of adequate characterization tools the advent of some new tools for structural elucidation of macromolecules has led to some revised thinking on coalification originally thought to be a process involving the full degradation of plant remains and subsequent reconstitution of these remains the general consensus today is that the process involves a selective preservation of certain resistant plant components followed by some minor reorganization of the biopolymers that survive the major components of plants do degrade and the resistant ones often constitute only a small fraction of the original mass of the plant materials this paper examines the most recent literature concerning coalification and focuses on the chemistry associated with coalification of certain recognizable plant remains that have been at the center of research activity for the past two decades thus we examine the recent knowledge of the chemistry of resistant biopolymers in extant and fossil wood cuticles resins spores and algae knowledge that has been assembled to establish the reaction pathways towards coal macromolecules

mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite abstract aluminum hydroxide boehmite rich pennsylvanian coals of high volatile a bituminous rank were found previously in the jungar coalfield inner mongolia china this paper reports new results on 48 bench samples of the cp2 coal from the adjacent adaohai mine daqingshan coalfield inner mongolia and provides new insights into the origin and modes of occurrence of the minerals and elements present in the cp2 coal compared to the same coal in the adjacent mines the cp2 coal in the adaohai mine has a higher rank ro ran 1 58 which is attributed to igneous intrusions during the late jurassic and early cretaceous epochs the proportion of inertinite 35 3 in the coal is higher than that in other late paleozoic coals in northern china but lower than that in the jungar coals minerals in the cp2 coal include diaspore boehmite gorceixite calcite dolomite siderite clay minerals kaolinite and ammonian illite and trace amounts of anatase fluorapatite quartz and pyrite based on mineral proportions in the coal bench samples the cp2 coal may be divided into four zones i to iv from bottom to top the major mineral in zones i and iv is kaolinite zones ii and iii are mainly composed of ammonian illite diaspore boehmite gorceixite calcite dolomite and siderite diaspore boehmite and gorceixite forming materials were derived from oxidized bauxite in the weathered crust of the benxi formation in the sediment source region during peat accumulation however gorceixite may have formed earlier than diaspore the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions the ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion the calcite and dolomite occur as epigenetic cell and fracture fillings and were probably derived from the igneous fluids compared to the common chinese and world coals the cp2 coal is enriched in cao 1 69 mgo 0 32 p2o5 0 214 f 207 g g ga 16 3 g g zr 446 g g ba 276 g g hg 0 33 g g and th 12 4 g g but has a lower sio2 al2o3 ratio due to the higher proportions of diaspore boehmite and gorceixite in the coal the f occurs mainly in gorceixite and fluorapatite the major carriers of ga are diaspore and kaolinite but not gorceixite barium mainly occurs in gorceixite and barite mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals the elements are classified into five associations by cluster analysis groups a b c d and e group a represents a ree be y se ga ge sc in pb bi nb ta tio2 w hg sb zr hf th u association most of the elements in group a are lithophile elements that occur in aluminosilicate minerals group b sn te zn cd v as cr cu mo ni re is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals elements in group c ad na2o al2o3 sio2 li k2o rb cs tl association probably occur in the clay minerals and diaspore group d consists of p2o5 ba f sr s and cl and with the exception of s they occur in minerals gorceixite and fluorapatite oxides of fe2o3 mno cao mgo make up group e and mainly occur in the carbonate minerals the coals are enriched in light rees and the lrees hrees have been highly fractionated with an average la yb n of 8 71 the heavy rees in the coals have a stronger organic affinity than the lrees

lithologic and geochemical investigations of the fire clay coal bed southeastern kentucky in the vicinity of sandstone washouts abstract the fire clay hazard no 4 coal bed of the middle pennsylvanian breathitt formation in eastern kentucky is interrupted by a series of discontinuous sandstone bodies this sand belt which includes two washouts was studied in perry county the coal thickens toward the interruptions and the coal between the sand bodies is highly disturbed several prominent durains in the upper bench of the coal bed are laterally continuous within the study area statistical analysis indicates that the durain layers contribute much of the vertical coal quality variation the sandstone bodies are inferred to be a result of post depositional fluvial activity and the disturbance of the coal between washouts is due to compaction related slumping a thin kaolinite rich lens similar to the flint clay parting was found below the main parting

coal deposits as potential alternative sources for lanthanides and yttrium abstract this paper presents data on widespread abnormal accumulations of lanthanides and yttrium rey in many coal deposits worldwide high rey contents 0 1 have been found in coal seams and coal ashes as well as in the host and basement rocks of some coal basins for a preliminary evaluation of coal ashes as an rey raw material not only the abundance but also the individual rey compositions were taken into account in this paper three rey distribution patterns for high rey coal ashes are fixed with lrey lan lun 1 mrey lan smn 1 and hrey lan lun

seismic anisotropy of oceanic upper mantle shear wave splitting methodologies and observations we develop methodologies to obtain accurate measurements of shear wave splitting and apply these techniques to examine the pattern of oceanic upper mantle anisotropy to obtain high quality estimates of receiver splitting at island stations we devise a stacking method that finds the optimum splitting parameters and 95 error region for teleseismic shear wave phases from a suite of earthquake events to obtain additional measurements in oceanic regions we develop techniques to measure splitting parameters and errors for ss phases that sample upper mantle anisotropy at their bounce points however we find the data are often of low resolution and anomalous characteristics are sometimes found that make splitting difficult to interpret ten second splitting of ss is observed across the banjo seismic array but we cannot unambiguously attribute this signal to mantle anisotropy at the bounce the receiver splitting methods are used to assess the adequacy of a two anisotropic layer model for the pacific region with fast polarization azimuth in the lithosphere oriented in the fossil spreading direction and in the asthenosphere oriented in the absolute plate motion direction this model has been proposed to explain surface wave data in the pacific ocean but our splitting results demonstrate that oceanic anisotropy patterns are more heterogeneous than would be predicted while the island splitting measurements could reflect the influence of individual hotspot upwellings hotspot effects do not appear to be universally dominant we propose that splitting observations alternatively indicate broad scale differences in the underlying character of oceanic upper mantle anisotropy associated with coherant patters of lithospheric structure and asthenospheric flow in particular splitting surface wave models and regional studies all support a model where lithospheric anisotropy throughout the south pacific has been erased or reoriented toward the absolute plate motion direction whereas more limited observations in the north pacific indicate that the fossil lithospheric signature appears to be preserved

on the relation between seismic anisotropy and finite strain because seismic anisotropy in the upper mantle is due primarily to lattice preferred orientation lpo of olivine crystals induced by deformation observations of anisotropy can provide constraints on mantle deformation and flow in this paper we use a previously published theory for deformation induced lpo ribe and yu 1991 to quantify the relation between seismic anisotropy and deformation for two model compositions a pure olivine dunite aggregate and a harzburgite comprising 70 olivine and 30 enstatite analytical and numerical solutions of the governing equations show that the predicted lpo and hence also the seismic anisotropy depends only on the finite strain and not on the deformation path by which that strain is produced the magnitude of the anisotropy depends only on the ratios c1 c2 and c2 c3 where c1 c2 c3 are the lengths of the principle axes of the finite strain ellipsoid and the directions of maximum and minimum compressional wave velocity vp coincide with the axes c1 and c3 respectively we calculate the percent anisotropies for compresional and shear waves propagating along the three principle axes of the finite strain ellipsoid as functions of the axial ratios c1 c2 and c2 c3 for our two model compositions however inferences of the magnitude of finite strain obtained using these results are likely to be minimum estimates because our theory neglects the effects of dynamic recrystallization finally we present as a byproduct of this study a new direct method for calculating the finite strain produced by an arbitiary deformation history

d rex a program for calculation of seismic anisotropy due to crystal lattice preferred orientation in the convective upper mantle summary models of development of lattice preferred orientation lpo of crystals aggregates in convec tive flow are necessary to interpret the anisotropic seismic signature of the earth s upper mantle for that purpose we previously developed a model of lpo evolution in olivine aggregates by plastic deformation and dynamic recrystallization by subgrain rotation and grain boundary migration this paper presents a refined version of that model called d rex for dynamic recrystallization induced lpo a public version of which is made available on our web site the code displays two new features 1 enstatite is incorporated in the aggregates and 2 grain boundary sliding gbs of small grains is taken into account enstatite is incorporated on the assumption of no direct interaction with olivine the fast a axis of enstatite grains tend to be parallel to the slow c axis of olivine which dilutes the total anisotropy grain boundary sliding is included using a threshold dimensionless volume fraction defined as the ratio of the initial size of the grains over the size for which gbs is the dominant mechanism of deformation grains with a dimensionless volume smaller than do not rotate by plastic deformation and their strain energy is set to zero comparison with torsion experiments at very large strain constrains the threshold dimensionless volume to 0 3 0 1 the incorporation of grain boundary sliding prevents the lpo from becoming singular at large strains and yields more realistic predictions our kinematic formalism and the model s semi analytical character insures that it is fast robust and stable it can be applied efficiently to arbitrary 3 d convective flows

a theory for plastic deformation and textural evolution of olivine polycrystals seismic anisotropy in the upper mantle is due primarily to preferred orientation of olivine crystals induced by progressive deformation in order to understand better the origin of seismic anisotropy we present a simple theory for plastic deformation and textural evolution of olivine polycrystals each crystal in the aggregate is assumed to deform by intracrystalline slip on three major slip systems whose hardnesses and stress exponents are known from experiments the evolving grain orientation distribution in the aggregate is calculated by minimizing the difference between the local crystal deformation and the global aggregate deformation subject to the constraint of global strain compatibility the axial compression texture predicted by our model agrees well to first order with that determined experimentally by nicolas et al 1973 although there are significant discrepancies in the details our results suggest that the orientation texture developed during progressive plane strain deformation is a nearly unique function of the finite strain such that the crystallographic axes 100 010 and 001 are concentrated around the finite strain axes a c and b respectively a b c this result may allow the state of finite strain at depth to be estimated from observations of seismic anisotropy

mineralogical and geochemical compositions of the coal in the guanbanwusu mine inner mongolia china further evidence for the existence of an al ga and ree ore deposit in the jungar coalfield abstract aluminum hydroxide boehmite and diaspore ga rey rare earth elements and y and al rich pennsylvanian taiyuan formation coals have previously been found in the jungar and daqingshan coalfields inner mongolia china gallium rey and al are potentially extractable and usable elements in combustion residues derived from these coals this paper reports new results on 50 bench samples of the no 6 coal from the guanbanwusu mine jungar coalfield inner mongolia and provides new data and evidence for the existence of an al ga rey ore deposit in the unique jungar coalfield the no 6 coal in the guanbanwusu mine has a low rank ro ran 0 56 and a low sulfur content st d 0 58 the proportion of inertinite in the coal 56 7 mineral free basis is higher than that of vitrinite 31 the minerals in the coal are mainly represented by kaolinite boehmite and chlorite along with variable proportions in some samples of calcite ankerite siderite and goyazite boehmite goyazite and part of the kaolinite were derived from bauxite in the weathered surface of the sediment source region ankerite calcite and siderite in the coal are of authigenic origin the chlorite in the guanbanwusu coals appears to have a chemical composition intermediate between cookeite and chamosite this mineral mainly occurs as cell fillings also indicating an authigenic origin and was probably derived from hydrothermal fluids a new mineral phase mainly composed of ti cl and fe is probably a ti bearing oxychloride or hydroxychloride compared to other chinese coals and to world hard coals the coal from the guanbanwusu mine is enriched in al2o3 9 34 p2o5 0 126 li 175 g g f 434 g g cl 1542 g g ga 12 9 g g sr 703 g g and th 12 9 g g but has a lower sio2 al2o3 ratio 0 74 due to the higher proportions of boehmite and goyazite in the coal the major carrier of p2o5 and sr is goyazite lithium mainly occurs in the chlorite cf cookeite kaolinite and possibly to a lesser extent illite fluorine in the coal has a major boehmite affinity but a small proportion may also occur in the organic matter and chlorite gallium in the coal largely occurs in goyazite chlorine is independent of other elements in the coal associated neither with moisture nor with organic matter but possibly occurring in molecular form cl2 and in the ti bearing oxychloride or hydroxychloride thorium in the coal occurs in the clay and accessory minerals and was mainly derived from detrital materials of the source region rare earth elements and y have a mixed organic and inorganic affinity largely occurring in goyazite group minerals and to a lesser extent boehmite and organic matter most coal benches and partings have either an l type or h type of rey enrichment owing respectively to the weathered bauxite source region and groundwater effects the al2o3 ga rey and possibly li in the guanbanwusu coals like those in coals from the jungar and adjacent daqingshan coalfields are industrially useful metals that could potentially be recovered from the relevant coal combustion residues it is suggested that if ga in ash 50 g g rey 800 900 g g sio2 al2o3 40 in ash and coal thickness 5 m the coal combustion residues would be expected to be suitably enriched in al2o3 and can be considered for al2o3 ga and rey recovery

rare earth element bearing coals from the russian far east deposits abstract coal seams up to 10 m in thickness with high rare earth element ree concentrations 300 1000 ppm were detected in some of the russian far east deposits this paper reports on the ree composition of the coals from a number of deposits the ree bearing coals are subdivided into three geochemical types studies of ree distributions across the coal seams examination of gravitation fractions and sem edx studies have revealed that the enriched coals seams contain ree mainly as sorbed forms by organic matter and clay particles and fine grained authigenic minerals the ree coals formed in 1 erosion tectonic depressions with wide spread weathering crusts in their basins and 2 volcano tectonic grabens in which coal accumulation occurred simultaneously with bimodal volcanism in the former case ree are thought to originate from the borderland in the second case from chambers of subalkaline magma the ree accumulation in the organic material occurred mostly during the peat stage due to mineralized ree bearing water coming to the basins the high ree contents up to 1 0 and even more of the combustion wastes their low lree hree ratios and the considerable estimated resources all place the ree bearing coals of the russian far east among new and very promising mineral resources for y and heavy lanthanoids as by products

teleseismic imaging of subaxial flow at mid ocean ridges traveltime effects of anisotropic mineral texture in the mantle summary deformation of peridotite caused by mantle flow beneath an oceanic spreading centre can result in the development of seismic anisotropy traveltime anomalies and shearwave splitting will develop as seismic energy propagates through such an anisotropic region thus providing a signature of the deformation field at depth in this study we investigate the nature of deformation associated with mantle upwelling for two models of flow in the upper 100 km of the mantle the finite strain fields of the passive upwelling model versus the buoyancy enhanced upwelling model are quite different this suggests that mineral aggregates deform differently in the two models thus developing seismic signatures that are distinguishable numerical estimates of the corresponding mineral textures are made using polycrystal theory for olivine with four operative slip systems the activation of a slip system is determined for each grain on the basis of the local critical resolved shear stress the computed grain deformation reflects a balance between stress equilibrium for the aggregate as a whole and strain continuity between neighbouring grains within the aggregate this approach enables a direct link to be made between the model flow fields and the resulting texture development given these mineral orientation distributions elastic parameters are calculated and wavefronts are propagated through the anisotropic structure traveltimes for teleseismic body waves are computed using ray theory and amplitudes are estimated for an across axis profile extending 100 km from the ridge axis relative p wave residuals of up to 1 s are predicted for the buoyant model with on axis arrivals being earliest since near vertical velocities are fastest beneath the axis on axis p wave arrivals for the passive model are half a second earlier than arrivals 60 km off axis and relative delays continue to increase slowly as distance from the ridge increases s wave splitting of almost a second is predicted for the buoyant model whereas less than a half second of splitting is determined for the passive model

simulation of fabric development in recrystallizing aggregates i description of the model abstract a new computer simulation of the development of grain shape and crystallographic preferred orientations in dynamically recrystallizing aggregates is presented this model is based on a uniform array of points each of which represents a small area of crystal this model combines homogeneous strains simplified versions of the lattice rotations predicted by taylor bishop hill theory mobile grain boundaries and the nucleation of subgrains it allows the progressive development of the fabrics and microstructures to be followed the limitations of the simplifying assumptions used in this model are discussed

anisotropic convection with implications for the upper mantle on the basis of polycrystalline theory describing the plasticity in olivine and enstatite the flow in a convection cell has been simulated using a finite element formulation the spatial variations in anisotropic properties are computed from the textures that evolve with the flow a kinematically constrained equilibrium based assumption is used to partition the macroscopic deformation among crystals within an aggregate we model the convection for one specific cell geometry and two sets of boundary conditions a complete map of textures throughout the cell is obtained the textured convection cell is structurally very heterogeneous and textures along streamlines do not correlate with the finite strain the results of the simulations indicate that during up welling a strong texture develops rapidly it convects during spreading and is attenuated during subduction results are compared with features of the upper mantle in our predictions the pattern of preferred orientation during spreading is inclined to the flow coordinates due to deformation by simple shear this is contrary to hess 1964 intuition that 001 slip planes of olivine orient themselves parallel to the flow planes yet the pattern is consistent with natural fabric data significant differences are observed as a function of depth within the cell the variations in the p wave velocities in this textured model mantle are analyzed and correspond well with observed seismic data

geochemistry of the blue gem coal bed knox county kentucky abstract the blue gem coal bed middle pennsylvanian westphalian b breathitt formation has low ash with some sample sites having less than 1 ash and low sulfur contents through parts of knox county kentucky most collection sites exhibit similar vertical elemental trends in ash geochemistry the relatively high ash 1 ash lower part of the bed displays enrichment in tio2 zr cr v and ni co zn rb and mn show enrichment at some sites a low ash 1 ash and a relative enrichment in sio2 k2o and rb and a relative decrease in cu ni co ba and mn when compared to the middle part of the bed principal components analysis indicates that the samples with an ash content 0 63 1 0 show associations for ni cu cr and co samples with between 1 01 2 0 ash display strong element associations that suggest increased clastic sediment contributions tio2 zr k2o rb sio2 the low ash content and the upwards decrease in trace concentrations both suggest that the blue gem peat swamp was ombrotrophic through at least a part of its geologic history

sub slab mantle anisotropy beneath south central chile knowledge of mantle flow in convergent margins is crucial to unravelling both the contemporary geodynamics and the past evolution of subduction zones by analysing shear wave splitting in both teleseismic and local arrivals we can determine the relative contribution from different parts of the subduction zone to the total observed sks splitting providing us with a depth constraint on anisotropy we use this methodology to determine the location orientation and strength of seismic anisotropy in the south central chile subduction zone data come from the tipteq network deployed on the forearc during 2004 2005 we obtain 110 teleseismic sks and 116 local good quality shear wave splitting measurements sks average delay times are 1 3 s and local s delay times are only 0 2 s weak shear wave splitting from local phases is consistent with a shape preferred orientation spo source in the upper crust we infer that the bulk of shear wave splitting is sourced either within or below the subducting nazca slab sks splitting measurements exhibit an average north easterly fast direction with a strong degree of variation further investigation suggests a relationship between the measurement s fast direction and the incoming ray s back azimuth finite element geodynamic modelling is used to investigate the strain rate field and predicted lpo characteristics in the subduction zone these models highlight a thick region of high strain rate and strong s wave anisotropy with plunging olivine a axes in the sub slab asthenosphere we forward model the sub slab sourced splitting with a strongly anisotropic layer of thick asthenosphere comprising an olivine a axis oriented parallel to the direction of subduction the subducting lithosphere is not thick enough to cause 1 2 s of splitting therefore our results and subsequent models show that the nazca slab is entraining the underlying asthenosphere its flow causes it to be strongly anisotropic our observation has important implications for the controlling factors on sub slab mantle flow and the movement of asthenospheric material within the earth

mantle anisotropy beneath the earth s mid ocean ridges observations of seismic anisotropy at oceanic spreading centres offer insights into mid ocean ridge processes and the formation of new plates here remote observations of seismic anisotropy beneath mid ocean ridges are made using measurements of source side shear wave splitting over 100 high quality measurements are made using earthquakes that occur near mid ocean ridges and transform faults but are observed at teleseismic distances in general for off axis ridge events the polarisation of fast shear waves phi prime prime is approximately parallel to the spreading direction nearer the ridge lesssim 50 km phi prime prime becomes more scattered and is often ridge parallel delay times delta t tend to increase from 1 s near the ridge axis to sim 3 s further away slow spreading regions gakkel and southwest indian ridges show smaller amounts of splitting than faster spreading centres at transform zones the pattern is more complex coverage beneath the east pacific rise is especially good and we observe a systematic increase in delay times in s wave splitting measurements compared to previous sks splitting observations made at ocean bottom seismometers one compatible explanation is the presence of horizontally aligned connected layers of melt at depth with an inclusion density which increases near the top of the layer this is also compatible with other observations of the lab discontinuity and surface wave derived measurements of radial anisotropy

robust geophysical integration through structure coupled joint inversion and multispectral fusion of seismic reflection magnetotelluric magnetic and gravity images example from santos basin offshore brazil abstractwe have applied a crossgradient joint inversion and geospectral visualization method to marine seismic reflection magnetotelluric gravity and magnetic data sets acquired along a 162 km profile across a segment of santos basin oil province in the continental margin of southeast brazil the main exploration targets are the top of the fractured precambrian crystalline basement and any concealed basement grabens the overlying presalt and salt carbonate deposits and the postsalt cover deposits the results of joint inversion clearly mapped the various units and are a significant improvement over previous models derived from separate 2d seismic reflection processing and 2d magnetotelluric imaging additionally multispectral fusion of these models resulted in a single image that permits highly constrained geologic interpretations enabling a better understanding of basin architecture we suggest that joint inversion and image fusion is the way forward for effective geophysical integration

introduction to this special section subsalt exploration salt basins occur worldwide figure 1 and large hydrocarbon deposits are often associated with the presence of salt structures due to favorable conditions for accumulation and trapping of oil and gas because of the cost and difficulty of drilling subsalt it is important to be able to image subsalt prospects correctly however the large velocity contrast between the salt and sediments and the complexity of many salt bodies make subsalt imaging a difficult task a step change in technology is therefore required and two recent workshops have been held to address the issues the workshop on subsalt imaging problems practical problems seeking solutions was held at the colorado school of mines in 2005 during which presenters from oil and service companies focused on the difficulties of subsalt imaging leveille et al tle 2005 the 2006 seg eage summer research workshop on subsalt exploration and development imaging interpretation and drilling what have we learned covered a wide range of sal

mineralogical and geochemical compositions of the pennsylvanian coal in the hailiushu mine daqingshan coalfield inner mongolia china implications of sediment source region and acid hydrothermal solutions abstract this paper investigates the mineralogical and geochemical compositions of the pennsylvanian coal in the hailiushu mine daqingshan coalfield neighboring previously reported al ga ree ore deposits including the adaohai mine in the same coalfield and deposits in the jungar coalfield using optical microscopy field emission scanning electron microscopy x ray fluorescence and inductively coupled plasma mass spectrometry the mineralogical and geochemical compositions in the coal were primarily controlled by the sediment source region during peat accumulation and by epigenetic acid hydrothermal solutions the hailiushu coal was deposited in a sub depression intermontane basin in the inner part of the orogenic belt with a sediment source region composed mainly of cambrian ordovician strata and archaean metamorphic rocks the minerals in the coal from the hailiushu mine dominantly consist of kaolinite with minor amounts of quartz sulfide and selenide minerals including chalcopyrite selenian galena galena sphalerite clausthalite and siegenite aluminophosphates and rhabdophane the coal is enriched in sio2 17 05 on average tio2 0 60 al2o3 13 71 zr 289 g g hf 7 09 g g and to a lesser extent f sc v cu ga se y nb mo cd sn la ta w hg pb bi and th titanium largely occurs in the kaolinite elements such as cu se sn hg pb and bi in the coal mainly occur in sulfide and or selenide minerals zirconium hf and nb were largely derived from the sediment source region the substitution of ti for al in kaolinite the corrosion of previously formed zircon anatase and quartz and the enrichment of middle rare earth elements in the coal were caused by the epigenetic acid hydrothermal solutions

mineralogy and geochemistry of the no 6 coal pennsylvanian in the junger coalfield ordos basin china abstract this paper discusses the mineralogy and geochemistry of the no 6 coal pennsylvanian in the junger coalfield ordos basin china the results show that the vitrinite reflectance 0 58 is lowest and the proportions of inertinite and liptinite 37 4 and 7 1 respectively in the no 6 coal of the junger coalfield are highest among all of the late paleozoic coals in the ordos basin the no 6 coal may be divided vertically into four sections based on their mineral compositions and elemental concentrations a high boehmite content mean 6 1 was identified in the no 6 coal the minerals associated with the boehmite in the coal include goyazite rutile zircon and pb bearing minerals galena clausthalite and selenio galena the boehmite is derived from weathered and oxidized bauxite in the weathered crust of the underlying benxi formation pennsylvanian a high pb bearing mineral content of samples zg6 2 and zg6 3 is likely of hydrothermal origin the no 6 coal is enriched in ga 44 8 g g se 8 2 g g sr 423 g g zr 234 g g rees 193 3 g g hg 0 35 g g pb 35 7 g g and th 17 8 g g gallium and th in the no 6 coal mainly occur in boehmite and the pb bearing selenide and sulfide minerals contribute not only to se and pb contents in the coal but also probably to hg content a high zr content is attributed to the presence of zircon and sr is related to goyazite the rees in the coal are supplied from the sediment source region and the rees leached from the adjacent partings by groundwater

seismic anisotropy in the sumatra subduction zone an important tool for understanding deformation occurring within a subduction zone is the measurement of seismic anisotropy through observations of shear wave splitting sws in sumatra two temporary seismic networks were deployed between december 2007 and february 2009 covering the fore arc between the fore arc islands to the back arc we use sks and local sws measurements to determine the type amount and location of anisotropy local sws measurements from the fore arc islands exhibit trench parallel fast directions which can be attributed to shape preferred orientation of cracks fractures in the overriding sediments in the sumatran fault region the predominant fast direction is fault trench parallel while in the back arc region it is trench perpendicular the trench perpendicular measurements exhibit a positive correlation between delay time and raypath length in the mantle wedge while the fault parallel measurements are similar to the fault parallel fast directions observed for two crustal events at the sumatran fault this suggests that there are two layers of anisotropy one due to entrained flow within the mantle wedge and a second layer within the overriding crust due to the shear strain caused by the sumatran fault sks splitting results show a nnw sse fast direction with delay times of 0 8 3 0 s the fast directions are approximately parallel to the absolute plate motion of the subducting indo australian plate the small delay times exhibited by the local sws 0 05 0 45 s in combination with the large sks delay times suggest that the anisotropy generating the teleseismic sws is dominated by entrained flow in the asthenosphere below the slab

modeling of lower mantle seismic anisotropy beneath subduction zones 1 recent observations of up to 6 secs of shear wave splitting in deep focus earthquakes from the tonga kermadec subduction zone provide insights into mantle dynamics near the 660 km discontinuity modeling of subduction body force stresses predicts large deviatoric stress 40 mpa in the topmost lower mantle below a viscosity increase at the 660 km discontinuity finite strain calculations produce significant amounts of natural strains 7 in the lower mantle and coherently aligned strain ellipses for a viscosity model with a viscosity increase at 660 km 5 10 secs of shear wave splitting is predicted compared to only 0 5 secs for uniform mantle viscosity for a viscosity increase model we predict that shear wave splitting reduces from 7 10 secs to 4 6 secs when deformation above 410 km is ignored and further reduces to 2 3 secs when deformation above 660 km is zeroed various conversions from finite strain to anisotropy have been explored predicted shear wave splitting magnitudes are comparable to those observed from the tonga kermadec subduction zone

forward modeling of the development of seismic anisotropy in the upper mantle development of seismic anisotropy in response to upper mantle flow is approached through an integrated numerical model this model allows to predict the splitting parameters for a shear wave propagating across an upper mantle which deformed in response to a given geodynamic process it consists of 1 thermo mechanical modeling of the finite strain field 2 modeling olivine lattice preferred orientation lpo generated by this strain field 3 calculation of the 3 d elastic properties associated with this lpo and 4 estimation of the shear wave splitting parameters the time lag between the fast and slow split shear wave arrivals dt and the polarization azimuth of the fast wave modeled olivine lpo are constrained relative to lpo measured in naturally and experimentally deformed peridotites comparison of predicted shear wave splitting parameters with seismological data allows us to quantify the possible contribution of the modeled upper mantle flow to the measured splitting values and hence to constrain the interpretation of shear wave splitting data in terms of upper mantle flow we use this forward model to investigate the seismic anisotropy generated in ocean basins by a velocity gradient between the plate and the deep mantle fast shear wave polarizations calculated assuming a constant plate motion are in good agreement with both the sks polarization and the fast propagation direction for p and rayleigh waves observed in the pacific and indian oceans suggesting that away from mid ocean ridges seismic anisotropy in oceanic basins primarily results from asthenospheric deformation by resistive drag beneath the plate delay times are however overestimated this may be ascribed to a stronger strain localization in nature or to partial erosion of the anisotropic layer by hotspots indeed hotspot activity may explain the short length scale variations of dt in the southern pacific finally twolayer models that simulate a change in pacific plate motion as suggested by the bend in the hawaii emperor chain fail to reproduce the observed shear wave splitting this is consistent with previous suggestions that the emperor chain track may not faithfully record the pacific plate absolute motion before 43 ma 1998 elsevier science b v all rights reserved

tracking mercury from the mine to the power plant geochemistry of the manchester coal bed clay county kentucky abstract the high volatile a bituminous manchester coal bed was sampled at five mine sites in central clay county southeastern kentucky the coal bed has a high mercury concentration at certain sites particularly in the high sulfur uppermost lithology whole coal hg contents range up to 0 52 ppm in a sample with 3 36 pyritic sulfur hg is enriched in the upper lithotype at several of the sites arsenic content exceeds 700 ppm ash basis for all of the whole channel samples and exceeds 1000 ppm for several of the lithotype samples regional geochemical trends from an area of approximately 75 60 km were determined using data from this study in combination with data published by the u s geological survey hg as pb and cl contents exhibit highs in the northwestern portion of the region within the smaller area covered by the detailed mine study the two western sites both have a high sulfur upper lithotype containing high levels of as and hg basement structures previously described in the study area could have influenced the regional coal rank and geochemistry possibly acting as conduits for mineralizing fluids

elements and phosphorus minerals in the middle jurassic inertinite rich coals of the muli coalfield on the tibetan plateau abstract the content modes of occurrence and origin of elements and phosphorus minerals in the jurassic coals of the muli coalfield on the tibetan plateau were investigated using optical microscopy field emission scanning electron microscopy in conjunction with energy dispersive x ray spectrometry x ray powder diffraction x ray fluorescence spectrometry and inductively coupled plasma mass spectrometry the muli coals l1 and l2 coals are of high volatile a bituminous to medium volatile bituminous rank characterized by low sulfur contents and are generally dominated by the inertinite group macerals predominantly semifusinite and fusinite the l1 coal contains abundant apatite 7 9 on average on an organic matter free basis and alumino phosphate minerals of goyazite gorceixite crandallite group 4 9 on average and accordingly the concentrations of elements f 253 g g on average p 2349 g g sr 526 g g and ba 790 g g are elevated as compared with common world hard coals the deposition of phosphorous bearing minerals in the muli coals was not derived from volcanic input penetration of ca and al rich solutions release of phosphorus from organic matter during plant decay and an appropriate sedimentary environment such as low ph low water table for peat and oxidizing conditions were critical factors in deposition of the phosphorus minerals

lanthanide yttrium and zirconium anomalies in the fire clay coal bed eastern kentucky abstract the fire clay coal bed in the central appalachian basin region contains a laterally persistent tonstein that is found in the coal throughout most of its areal extent the tonstein contains an array of minerals including sanidine quartz anatase and euhedral zircon that constitutes strong evidence for a volcanic origin of the parting for this study five samples of the tonstein and four sets of coal samples underlying the tonstein were collected from five sites in eastern kentucky inductively coupled plasma mass spectroscopy icp ms analysis of the tonstein and underlying coal collected from four sites in eastern kentucky show that although zr concentrations are high in the tonstein 570 1820 ppm on a coal ash basis cab they are highest in the coal directly underlying the tonstein 2870 4540 ppm cab a similar enrichment pattern is observed in the concentration of y plus the sum of the rare earth elements y ree total y ree concentrations in the five tonstein samples range from 511 to 565 ppm cab however y ree contents are highest in the coals directly underlying the tonsteins values range from 1965 to 4198 ppm cab scanning electron microscopy of samples from coal which directly underlies two of the tonstein samples show that ree rich phosphate tentatively identified as monazite commonly infills cracks in clays and cells in clarain and vitrain zircon is rare and commonly subhedral on the basis of coal chemistry and grain morphology we suggest that volcanic components in the tonstein were leached by ground water the leachate rich in y and ree precipitated as authigenic mineral phases in the underlying coal

rare earth elements and yttrium in lithotypes of bulgarian coals abstract rare earth element and yttrium abundances in vitrain xylain liptain fusain and whole coal samples from bulgarian coal deposits have been studied vitrain xylain and liptain are depleted while fusain is enriched in ree and y as compared to the whole coal samples from which they were selected chondrite normalized patterns show relative enrichment of light lree against heavy hree rare earth elements negative eu anomaly and positive lu anomaly the shale normalized patterns of the lithotypes reveal an increase from lree to hree while those of the whole coal samples and mineral interlayers are less fractionated the petrographic composition of the coals is of secondary importance for the concentration of the ree and y the main factors are the source area and the input of dissolved ree and y into the coal depositional sites

the effects of volcanic ash on the maceral and chemical composition of the c coal bed emery coal field utah abstract volcanic ash which fell in the peat swamp that formed the upper cretaceous c coal bed ferron sandstone member of the mancos shale utah produced semi impermeable layers that caused the ponding of surface waters coal samples from directly above tonsteins altered volcanic ash partings are enriched in desmocollinite telinite and detrocollinite as a result of poorly drained swamp conditions coal samples from directly below tonsteins are enriched in semifusinite inertodetrinite and fusinite as a result of well drained conditions leaching of the volcanic ash or the incorporation of volcanic ash in peat provided a source for many elements including zr nb th and ce that are enriched in coal samples taken from directly above and below tonsteins

petrological geochemical and mineralogical compositions of the low ge coals from the shengli coalfield china a comparative study with ge rich coals and a formation model for coal hosted ge ore deposit abstract to better understand the formation mechanism of coal hosted ge ore deposits this paper reports on the petrological mineralogical and geochemical compositions of the low ge coals in the shengli coalfield inner mongolia china using optical microscopy field emission scanning electron microscopy x ray fluorescence x ray diffraction and inductively coupled plasma mass spectrometry the samples in the present study closely neighbor the previously reported wulantuga coal hosted ge ore deposit both no 6 coal in comparison with the wulantuga ge rich coals the low ge coals of the shengli field display higher moisture 27 59 on average and lower pyritic sulfur contents 0 53 both the low ge and ge rich coals are generally high in inertinite and have varying but relatively low huminite contents preservation of fecal pellets as macrinite is notable in both the low ge and ge rich coals and the position of the fecal pellets appears to be within tunnels or chambers within the wood quartz kaolinite pyrite and gypsum are the major crystalline phases identified in most of the ge rich and low ge coals but the low ge coals contain significantly less pyrite and are more abundant in non mineral ca and mg ca oxalate of authigenic origin is observed generally occurring as cell fillings in the low ge coals otherwise mineral free organic matter in the low ge coals would be expected to have an inherent ash yield of around 6 derived from the inorganic elements mainly non mineral ca and mg that occur either in the organic matter or as dissolved ions in the pore water and form the sulfate species in low temperature oxygen plasma ash residues the highly elevated trace elements including be ge as sb w hg and tl that occur in the ge rich coals of the wulantuga deposit are significantly depleted in the low ge coals lateral migration of ge w and as hg sb tl rich solutions through the original peat swamp for the wulantuga ge ore deposit has led to significant enrichment of ge on the margin of the coal basin but decreasing ge concentrations toward to the inner part of the basin such a migration direction is different to those in the previously reported for the hydrothermal solutions in the lincang yunnan of china and spetzugli russian far east ge ore deposits where the solutions migrated vertically from granite to peat along faults and led to a dome shaped ge distribution in the relevant coal seam

geochemical and palynological indicators of the paleoecology of the river gem coal bed whitley county kentucky abstract the river gem coal bed upper westphalian a was sampled at five sites in a single mine in whitley county kentucky previous petrographic and sulfur analyses of the collected interval samples showed that the coal bed could be divided into a basal low sulfur lithotype a middle high sulfur bone lithotype and an upper high sulfur lithotype at one location a high sulfur rider unit is present in this study we have conducted detailed palynological analyses on all of the interval samples and ash geochemistry on the upper high sulfur lithotype intervals and two of the basal high sulfur basal lithotype intervals geochemical analyses show that as and pb are generally high in the high sulfur upper lithotypes from all five sites carbonates having associated high levels of ba and sr are important in the ash geochemistry of the lower low sulfur lithotypes ga ge and w are enriched in the higher vitrinite lithotypes among the low sulfur samples the basal lithotype at each of two sites which was analyzed in detail is enriched in yttrium plus the lighter rare earth elements the basal low sulfur lithotypes are dominated by arboreous lycopod spores the middle low sulfur portion of the bed is dominated by herbaceous lycopsids densosporites at the base of the unit and becomes increasingly enriched in lycospora towards the top of the unit indicating that the peat forming environment became wetter the greatest arboreous lycopod spore abundances in the upper high sulfur portion the bed along with an overlying marine roof indicates that peat deposition was terminated by a marine inundation

mineralogy and geochemistry of boehmite rich coals new insights from the haerwusu surface mine jungar coalfield inner mongolia china abstract boehmite rich coal of pennsylvanian age was discovered earlier at the heidaigou surface mine jungar coalfield inner mongolia china this paper reports new results on 29 bench samples of the no 6 coal from a drill core from the adjacent haerwusu surface mine and provides new insights into the origin of the minerals and elements present the results show that the proportion of inertinite in the no 6 coal is higher than in other late paleozoic coals in northern china based on mineral proportions boehmite to kaolinite ratio and major element concentrations in the coal benches of the drill core the no 6 coal may be divided into five sections i to v major minerals in sections i and v are kaolinite sections ii and iv are mainly kaolinite with a trace of boehmite and section iii is high in boehmite the boehmite is derived from bauxite in the weathered surface benxi formation in the sediment source region the no 6 coal is rich in al2o3 8 89 tio2 0 47 li 116 g g f 286 g g ga 18 g g se 6 1 g g sr 350 g g zr 268 g g rees 172 g g pb 30 g g and th 17 g g the elements are classified into five associations by cluster analysis i e groups a b c d and e group a ash sio2 al2o3 na2o li and group b ree sc in y k2o rb zr hf cs u p2o5 sr ba ge are strongly correlated with ash yield and mainly have an inorganic affinity the elements that are negatively or less strongly correlated with ash yield with exceptions of fe2o3 be v and ni are grouped in the remaining three associations group c se pb hg th tio2 bi nb ta cd sn group d co mo tl be ni sb mgo re ga w zn v cr f cu and group e s as cao mno fe2o3 aluminum is mainly distributed in boehmite followed by kaolinite the high correlation coefficients of the li ash li al2o3 and li sio2 pairs indicate that li is related to the aluminosilicates in the coal the boehmite rich coal is high in gallium and f which occur in boehmite and the organic matter selenium and pb are mainly in epigenetic clausthalite fillings in fractures the abundant rare earth elements in the coal benches were supplied from two sources the bauxite on the weathered surface of the benxi formation and from adjacent partings by groundwater leaching during diagenesis the light rare earth elements lrees are more easily leached from the partings and incorporated into the organic matter than the heavy rees leading to a higher ratio of lrees to hrees in the coal benches than in the overlying partings