mineralogy and geochemistry of ammonian illite in intra seam partings in permo carboniferous coal of the qinshui coalfield north china abstract ammonian illite is observed to be presented in the intra seam coal partings of the permo carboniferous coal seams from the qinshui coalfield north china this paper provides new insights into its geochemical and mineralogical characteristics as well as the factors influencing its formation and its nitrogen isotope ratios the interlayer cations of ammonian illite in the samples presented in this study were dominated by nh 4 with a certain amount of k and distributed homogeneously in each illite layer ammonian illite has an nh 4 nh 4 k ratio of 0 87 on average with a basal spacing d 001 10 267 a on average greater than those of potassian illite and muscovite but lower than that of tobelite the average stoichiometric formula of the ammonian illite was inferred as nh 40 67 k 0 11 al 1 90 fe 0 06 mg 0 04 al 0 68 si 3 32 o 10 oh 2 and the average si al iv ratio 4 88 was found to be higher than that of tobelite this indicates that the conversion of ammonian illite to tobelite includes the expulsion of si from the tetrahedral sheets and the incorporation of al into the octahedral and tetrahedral sheets the d 005 is influenced not only by the nh 4 nh 4 k ratio but also to some extent by the entrance of al iv into tetrahedral sites it is inferred that the ammonian illite was formed by the incorporation of si into pre existing kaolinite during diagenesis and that its formation was influenced not only by the diagenetic temperature but also by the depositional environment brackish water favors the formation of ammonian illite during deposition the nh 4 of the ammonian illite was mainly derived from pyrrolic n 5 and pyridinic n 6 nitrogen groups at the margins of the coal s carbon matrix during diagenesis on average it has a 15 n value of 8 0 much higher than that of total coal nitrogen 3 9 on average this is related mainly to the higher 15 n values of n 5 and n 6 than the quaternary nitrogen group n q within the carbon matrix

evidence for multiple sources for inorganic components in the tucheng coal deposit western guizhou china and the lack of critical elements abstract terrigenous materials from sediment source regions are important controls on the types and concentrations of inorganic components in coal the kangdian upland dominated by the emeishan basalts is the dominant terrigenous supplier for most of the late permian coals as well as for their associated host rocks roof and floor strata in southwestern china the high volatile bituminous coals nos 3 and 6 coals are the two major minable coal seams in the tucheng coal deposit in southwestern china unlike most late permian coals in this region that are characterized by elevated concentrations of the element assemblage sc v cr co ni cu zn se these two coals are not enriched in this assemblage although se is slightly concentrated the mineralogical e g relatively abundant quartz and mixed layer illite smectite and elemental distribution patterns e g spider diagrams of rare earth elements discrimination diagrams of al2o3 tio2 and zr tio2 nb y and elemental assemblages indicate that the inorganic components in the two coal seams were mainly derived from unidentified volcanic arc and or distal orogens while the clastic components in the roof and floor strata of the two coal seams were mainly supplied by the high ti emeishan basalts the two partings in the two coal seams identified as tonsteins were probably derived from the final rejuvenated activity of the emeishan plume critical elements in the two coals and associated non coal horizons partings roof and floor strata are economically unpromising indicating that prospecting for late permian coal hosted critical metal ore deposits in the vicinity of the emeishan plume in southwestern china should not be focused on coals with inorganic components derived mostly from distal volcanic arcs and orogens and high ti emeishan basalts and a minor contribution of volcanic ashes resulting from the final rejuvenated activity of the emeishan plume

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

spatial autocorrelation of topographic index in catchments summary spatial autocorrelation represents the association of a spatial parameter around neighborhoods and it usually distorts the statistics of the distribution of the parameter topographic spatial autocorrelation is rooted with the distribution of land surface elevation using moran s i statistics originating from geographic studies this paper presents a method to quantify the spatial autocorrelation of topographic index ti in catchments derived from digital elevation models dem positive autocorrelation similarity or homogeneity of ti is found over a wide range of spatial extents it declines with the increasing of spatial extents but becomes relatively static beyond a threshold area of approximately 1 km 2 the analysis of the effect of dem grid size resolution on the spatial autocorrelation shows that the effect is characterized by a similar pattern and critical grid size for selected catchments with different terrains based on these analyses further discussions address some issues in catchment hydrology such as the appropriate dem sizes for deriving ti and the causes for the empirical linear or log linear relation between mean ti and dem grid size

physical interpretation and sensitivity analysis of the topmodel the topmodel is a variable contributing area conceptual model in which the predominant factors determining the formation of runoff are represented by the topography of the basin and a negative exponential law linking the transmissivity of the soil with the distance to the saturated zone below the ground level although conceptual this model is frequently described as a physically based model in the sense that its parameters can be measured directly in situ in line with the analysis of various conceptual rainfall runoff models conducted by franchini and pacciani j hydrol 122 161 219 1991 a detailed analysis of the topmodel is performed to arrive at a closer understanding of the correspondence of the assumptions underpinning the model with the physical reality and in particular the role that topographic information expressed by the topographic index curve and the nature of the soil expressed by saturated hydraulic conductivity and its decay with soil depth have within the model itself also investigated is the extent to which the model parameters actually reflect the physical properties to which they refer and how far their values offset the inevitable schematisation of the model the various applications to real situations include the sieve basin river arno tributary which was used for the comparison of conceptual rainfall runoff models described in the above mentioned study by franchini and paccini this allows that analysis to be extended to the topmodel

mineralogical composition of late permian coal seams in the songzao coalfield southwestern china abstract coals from three seam sections in the songzao coalfield sw china are mainly high ash high sulphur semianthracites minerals within the songzao coals are mainly kaolinite pyrite or marcasite in some cases and quartz with various proportions of non kaolinite clay minerals carbonates feldspars and anatase the illite and mixed layer illite smectite i s are na rich in some of the datong coal samples the i s in the lower coals of the datong section is most likely an alteration product of dispersed volcanic ash due to the availability of necessary ions e g k na and mg in the marine influenced coal swamp organically bound na which was expelled from the organic matter with coal rank advance especially with anthracitization may have supplied additional na for the formation of na rich illite authigenic i s also occurs in a tonghua coal ply that is overlain by a mafic bentonite and underlain by an alkali tonstein potassium na and mg for the formation of such i s were probably derived from the leaching of the adjacent alkali tonstein and mafic bentonite although the marine water was also a possible supplier of the alkali elements authigenic i s is rare in coal plies that occur further away from the altered volcanic layer leaching of the volcanic claystones in the tonghua coal seam probably led to the formation of relatively abundant anatase and rhabdophane in the underlying coal ply fracture filling ree minerals probably ree hydroxides or oxyhydroxides also occurring in that coal ply crystallized from ascending ree rich hydrothermal fluids probably associated with contemporaneous volcanic activity

wavelet based regularization of the extracted topographic index from high resolution topography for hydro geomorphic applications high resolution topography e g 1 m digital elevation model dem from light detection and ranging lidar offers opportunity for accurate identification of topographic features of relevance for hydrologic and geomorphologic modelling yet the computation of some derived topographic properties such as the topographic index ti is characterized by daunting challenges that hamper the full exploration of topography based models particular problems for example arise when a distributed or semi distributed rainfall runoff model is applied to high resolution dems indeed the characteristic dependency between landscape resolution and the computed ti distribution results in the formation of un physical unconnected saturated zones which in turn cause unrealistic representations of rainfall runoff dynamics in this study we present a methodology based on a multi resolution wavelet transformation that by means of a soft thresholding scheme on the wavelet coefficients filters the noise of high resolution topography to construct regularized sets of locally smoother topography on which the ti is computed while the methodology needs a somewhat arbitrary definition of the wavelet coefficients threshold our study shows that when the information content entropy of the ti distribution is used as a filtering efficiency metric a critical threshold automatically emerges in the landscape reconstruction the methodology is demonstrated using 1 m lidar data for the elder creek river basin in california while the proposed case study uses a topmodel approach the methodology can be extended to different topography based models and is not limited to hydrological applications copyright 2012 john wiley sons ltd

geochemistry of source rock controlled late triassic coal an example from the dabaoding coal mine in panzhihua sichuan province southwestern china abstract the geochemistry of source rock controlled coals from the late triassic daqiaodi formation in the dabaoding coal mine of the southwestern sichuan province was investigated a total of 15 coal samples 6 parting samples and 4 roof and floor rock samples from the d15 3 and d18 coals were subjected to proximate and ultimate analyses for coal quality by using lta xrd with siroquant software for minerals xrf for major element oxides icp ms for trace elements icp cct ms for as and se ise for f and a dma 80 analyzer for hg results indicate that the dabaoding d15 3 and d18 coals are classified as low ash and low volatile bituminous coal minerals in coals are dominated by quartz kaolinite illite and dolomite most trace elements in the dabaoding coals are depleted or at normal levels relative to chinese coals or world hard coals except for cr with slight enrichment the dabaoding coals and host rocks are characterized by weakly positive ce and y anomalies strongly positive gd anomalies and weakly negative eu anomalies based on paleogeographical mineralogical and geochemical evidence the sediment source rocks of the daqiaodi coal bearing strata are identified as the panzhihua trachyte at the top of the kangdian upland which exerted crucial impacts on the dabaoding coals

sulfur in coals a review of geochemistry and origins geochemical studies of sulfur in coals comprise several major aspects relating to the nature and origin of sulfur in coals including the abundance and distribution of sulfur in coal seams abundance of sulfur in coal lithotypes and macerals characteristics and geochemical significance of sulfur containing organic compounds sulfur isotopic studies relating to the sources of sulfur in coals and sedimentary environments controlling the geochemistry of sulfur in coal a review of the evidence suggests that the variation of sulfur in coals is closely related to the depositional environments of coal seams for low sulfur coal 1 s sulfur is derived primarily from parent plant material for medium sulfur 1 to 3 s and high sulfur 3 s coals there are two major sources of sulfur 1 parent plant material and 2 sulfate in seawater that flooded peat swamps abundances of sulfur in coal are largely controlled by the degree of seawater influence during peat accumulation and by postdepositional changes diagenesis in high sulfur coals seawater sulfate diffuses into the peat which is subsequently reduced by bacteria into hydrogen sulfide polysulfides and elemental sulfur reaction of hydrogen sulfide with ferrous iron generates fine pyrite crystals and mackinawite fes0 9 mackinawite reacts with elemental sulfur to converts to greigite fe3s4 and then to framboidal pyrite the reduced sulfur species in the peat hydrogen sulfide elemental sulfur and polysulfides react with the organic matter to form organic sulfur compounds during coal diagenesis nodular pyrite forms permineralized peat was formed during diagenesis which contains appreciable fraction of pyrite after coal is solidified pyrite can deposit in the cleats from circulating groundwater epigenetic pyrite veins may be deposited from basinal fluids thus pyrite forms during various stages of coal formation from peat to coal as well as late epigenetic activity the relationships between sulfur abundance in coal seams and depositional environments of coals were reviewed for cases from the u s china u k germany hungary turkey indonesia and brazil in most cases low sulfur coals formed in a fluvial environment and high sulfur coals were deposited in seawater influenced environments there are exceptions for example turkish lignites formed in freshwater environments are high sulfur sulfur sources other than seawater are needed for these high sulfur coals the superhigh organic sulfur shos coals are highly enriched in organic sulfur but depleted in pyritic sulfur the shos coals were deposited in sulfur rich iron poor environments such as carbonate platforms or in an iron poor and clastic starved environment in which algae accumulate speciation of organic sulfur compounds in coal appears to be related to coal rank thiophenic compounds are more abundant in bituminous coal and anthracite than in low rank coals

mineralogy and geochemistry of late permian coals from the taoshuping mine yunnan province china evidences for the sources of minerals abstract this paper describes the mineralogy and geochemistry of a batch of 17 coal samples covering the late permian longtan formation from a drill core from the taoshuping mine eastern yunnan province china the results show that minerals in the coals include quartz kaolinite calcite chamosite pyrite mixed layer i s and minor marcasite siderite anatase ankerite and dolomite modes of occurrences of authigenic quartz and chamosite suggest that they were mainly precipitated from fe mg rich siliceous solution derived from the weathering of emeishan basalt which was induced by mantle plume eruption during late middle permian and covers most places of southwest china kaolinite and mixed layer i s are mainly of detrital origin correspondingly the elevated trace elements including v cr co and ni in the coals are closely related to emeishan basalt trace amounts of detrital calcite ankerite and siderite in the coals probably originated from the maokou limestone the frequent presence of high temperature quartz indicates that felsic volcanic eruption took place through the entire late permian epoch mineral matter in the coals was not only derived from emeishan basalt in the kangdian oldland but also felsic volcanic ashes mafic volcanic ashes and limestone of the maokou formation

mineralization of ree y nb ta zr hf in wuchiapingian coals from the liupanshui coalfield guizhou southwestern china geochemical evidence for terrigenous input abstract abundances modes of occurrence enrichment and origin of critical elements in coal and coal bearing sequences have attracted much attention in recent years previous investigations have attributed ree y nb ta zr hf mineralization in coals and in intra and inter seam tuffs in coal bearing sequences to alkali volcanic ash eruptions and subsequent hydrothermal alteration in this study two major minable coal seams d101 and w407 that are located in the lowermost and uppermost wuchiapingian longtan formation in the liupanshui coalfield guizhou southwestern china were investigated in order to better understand the mechanism of ree y nb ta zr hf enrichment in these coals elevated concentrations of ree y nb ta zr hf in the d101 coal are dominantly due to the alkaline volcanic material forming the top of the emeishan large igneous province elip which served as a terrigenous source region for the coal basin and to airborne volcanic ash which occurs as an intra seam tonstein within the coal seam both of the two source materials were subsequently subjected to groundwater leaching resulting in redistribution of the rare earth elements and y rey leading to an uneven distribution of rey and zr along the studied coal seam sections the average rey oxides in the d101 and w407 coals are 2682 and 1260 ppm both on ash basis respectively and the outlook coefficients are 0 79 and 1 15 respectively indicating that both ashes from the two coals are potential raw sources for rey

paleoenvironmental clues archived in non marine pennsylvanian lower permian limestones of the central appalachian basin usa abstract nonmarine limestones are a key component of the upper middle pennsylvanian through lower permian succession in the appalachian basin previous interpretations of their environments of deposition range from brackish coastal mudflats to hydrologically open freshwater lake complexes with peat forming vegetated marshes to semi closed or closed possibly saline shallow lakes developed on a distal alluvial plain ostracode wackestones packstones some exhibiting laminations and with fish debris articulated ostracode shells and phosphatic clasts define the lower portions of limestone beds or benches passing upward into ostracode peloidal wackestones packstones and intraclastic skeletal peloidal packstones grainstones desiccation features and rooting structures which are developed in the upper portions of the limestones record subaerial exposure pedogenic alteration and desiccation pseudomicrokarst and caliche like vadose and early diagenetic phreatic cements suggest a seasonally dry subhumid to semi arid regional climate many of the sedimentologic and diagenetic features of the limestones are characteristic of palustrine carbonates which coupled with their stratigraphic relation to paleo vertisols siliciclastics and coals indicate that they formed in broad seasonal wetland pond complexes that developed on distal regions of a low gradient distal alluvial plain under seasonally dry subhumid to semi arid climates integration of sr isotopic compositions of shark teeth with previously published stable isotope compositions of the limestones suggests that these purely continental environments were hydrologically semi closed to closed systems repeated stacking of these features at the bed to limestone bench scale defines repeated shallowing upward drying cycles at the 103 to 104 yr scale which were likely climate driven

enrichment and distribution of elements in the late permian coals from the zhina coalfield guizhou province southwest china abstract this paper investigates the mineralogy and geochemistry of four coal beds wjb 6 wjb 7 fhs 23 and fhs 27 coals of the late permian in the zhina coalfield western guizhou province china the investigated coals reach the semianthracite anthracite coal rank and have super low to low ash yields the sulfur contents vary considerably through coal sections and are mostly in the range of medium high sulfur coal the mineral assemblage present in the fhs 23 and fhs 27 coals is mainly made up of pyrite and rectorite the wjb 6 and wjb 7 coals have different mineralogy with kaolinite and rectorite dominant in the former as well as quartz and rectorite in the latter these coals contain high concentrations of nb and ta but li is only enriched in the wjb 6 coal rectorite and anatase in these coals are important hosting phases of nb and ta while kaolinite and to a lesser extent chamosite in the wjb 6 coal are dominant carriers for the elevated li concentration the terrigenous material input the marine influence and the effect of circulating hydrothermal solution are the pivotal geological factors causing geochemical anomalies in coals investigated the high sulfur coals were subjected to an enhanced marine influence in the depositional environment as well as to a higher terrigenous influx when compared with the medium sulfur and low sulfur coals resulting in higher concentrations of s fe as mo u hg in the former coals than in the latter ones the anomalous enrichment of nb and ta in these coals as well as of li in the wjb 6 coal is the result of the contributions from ascending hydrothermal solutions although source rocks e g high ti basalt may provide relatively high background abundances of nb ta and li

distribution of sulfur and pyrite in coal seams from kutai basin east kalimantan indonesia implications for paleoenvironmental conditions abstract thirteen miocene coal samples from three active open pit and underground coal mines in the kutai basin east kalimantan indonesia were collected according to our microscopical and geochemical investigations coal samples from sebulu and centra busang coal mines yield high sulfur and pyrite contents as compared to the embalut coal mine the latter being characterized by very low sulfur

analysis origin and significance of mineral matter in coal an updated review abstract the material classed as mineral matter in coal embraces crystalline mineral materials as well as a range of inorganic elements that occur in non crystalline form this review outlines the methods that may be used to evaluate the percentage of mineral matter for a coal sample as opposed to the ash yield and to identify the minerals their individual percentages and their modes of occurrence within the coal the principal techniques include low temperature oxygen plasma ashing quantitative evaluation of x ray diffraction data observation using optical microscopy and a combination of observation chemical analysis and in some cases mapping based on scanning electron microscopy and related methods a range of other techniques may also be used to provide additional information on particular mineral matter components processes responsible for mineral matter formation include detrital input biogenic activity and authigenic precipitation at different stages of the coal s depositional and post depositional history differential migration of non mineral inorganic elements may also occur in lower rank coals and expulsion of non mineral inorganics may take place with rank advance knowledge of the mineral matter may be of assistance in understanding the modes of trace element occurrence with implications for assessing possible environmental impacts and also the potential for recovery of economic products from coal the behaviour of different mineral matter components at high temperatures is also discussed as well as methods for mineralogical analysis of ashes and other coal utilization products information from mineral matter studies may provide an improved basis for understanding coal formation and for evaluating the response of particular coals to different combustion gasification and coking processes

petrological mineralogical and geochemical compositions of early jurassic coals in the yining coalfield xinjiang china abstract the petrological geochemical and mineralogical compositions of 10 coal seams early jurassic from an exploratory borehole hole zkj502 in the jieliangzi mining area of the yining coalfield xinjiang uygur autonomous region china were investigated using optical microscopy and field emission scanning electron microscopy in conjunction with an energy dispersive x ray spectrometer fe sem eds as well as x ray powder diffraction xrd x ray fluorescence xrf and inductively coupled plasma mass spectrometry icp ms the yining coals are of subbituminous to highly volatile c bituminous in rank vitrinite reflectance average 0 49 and are characterized by low sulfur content average 0 45 low ash yield average 4 10 high volatile matter average 38 82 high proportion of inertinite average 49 5 and low concentrations of most trace elements relative to the upper continental crust the rare earth elements and yttrium in the yining coals are mainly characterized by light and heavy rey enrichment the minerals in the yining coals are dominated by quartz kaolinite and siderite followed by pyrite bassanite and hexahydrite along with small proportions of illite calcite dolomite gorceixite goyazite ankerite marcasite diaspore florencite hematite and millerite the similarity between the yining coals and the magmatic rocks from the peripheral mountain area of the basin in terms of the al 2 o 3 tio 2 ratio the rey enrichment type the rey distribution patterns and the eu anomalous fractionation suggest that the sediment source region was mainly carboniferous volcanic rocks andesite and basalts on peripheral mountains the acid conditions and lowered water table during peat accumulation may have caused detrital minerals to be leached leading to the relatively low ash yield another reason for the low ash yield may be the simple coalfield structure and poor groundwater migration channels in the rocks and coal seams in the central zone of the basin which would limit the minerals carried by the groundwater into coals a number of authigenic minerals quartz kaolinite siderite and gorceixite occur as cell fillings and elevated concentrations of li be sc v cr co ni cu zn ga rb zr nb mo cs hf w pb th and rey occur in nos 26 and 27 coals indicating that there was an injection of a small scale solution

occurrence and origin of minerals in a chamosite bearing coal of late permian age zhaotong yunnan china the minerals found in the no 5 coal late permian from the zhaotong coalfield yunnan province southwestern china have been examined and found to consist mainly of kaolinite pyrite chamosite quartz and calcite with trace amounts of illite and mixed layer illite smectite the proportion of chamosite in clay minerals ranges from 32 to 56 wt with an average of 46 wt chamosite is distributed not only in collodetrinite but also occurs as cell fillings in fusinite semifusinite and telinite the high content and mode of occurrence of chamosite in this mine indicate its formation by interaction of kaolinite with fe mg rich fluids during early diagenesis except for a minor amount of terrigenous quartz most quartz is of authigenic origin and formed from kaolinite desilication the calcite content of the no 5 coal is 1 4 6 3 with an average of 3 and is distributed in collodetrinite and as cell fillings of coal forming plants calcite originated from seawater invasion during peat accumulation pyrite occurs in several ways as massive framboidal isolated enhedral anhedral and euhedral forms in addition the presence of a large amount of pyritized red algae provides strong evidence of seawater invasion during peat accumulation the red algae may have played an important role in the enrichment of sulfur in the coal the characteristic assemblage of minerals in this mine resulted from a unique basinal environment in which the mineral matter was derived from a basaltic source region volcanic activity and seawater transgression during coal formation

power law distributions of discharge mass and energy in river basins river networks constitute dissipative systems with many spatial degrees of freedom previous work by mandelbrot 1983 and bak et al 1987 1988 1990 suggests that such systems will follow power law distributions in their mass and energy characteristics it is shown that this is the case for river networks where the exponent in the distribution p x x x is approximately equal to 0 45 and 0 90 for discharge and energy respectively in the case of several networks analyzed in north america when these variables are calculated for each individual link throughout the drainage network an explanation of the values of is offered based on the fractal structure of rivers and on principles of energy expenditure in river basins

the mode of occurrence and origin of minerals in the early permian high rank coals of the jimunai depression xinjiang uygur autonomous region nw china abstract this paper investigates the mineralogy of coal and non coal samples from the haerjiao exploration area in the jimunai depression xinjiang uygur autonomous region northwestern china using x ray diffraction xrd optical microscopy and scanning electron microscopy with an energy dispersive x ray spectrometer sem edx the minerals in the anthracite proximal to the igneous intrusions are represented by the occurrence of chlorite muscovite and illite which are absent in the semianthracite distal to the igneous intrusions kaolinite the dominant mineral in the semianthracite decreases in abundance or even disappears in the anthracite muscovite and illite in the anthracite are interpreted to result from the alteration of the kaolinite precursor and possibly formed by the interaction of kaolinite and elements e g k fe and mg from igneous hydrothermal solutions the formation of chlorite is the result of the transformation of kaolinite due to the interaction of kaolinite with fe mg rich solutions during the diagenetic stage and the direct epigenetic precipitation from fe mg rich igneous siliceous hydrothermal fluids calcite ankerite and sulfide minerals resulted from epigenetic precipitation from hydrothermal fluids cleat fracture mineralization indicates that the fe mg rich hydrothermal fluid from which chlorite precipitated was introduced earlier than the ca rich fluid from which calcite precipitated the injection of hydrothermal solutions that formed sulfide minerals occurred at the latest stage

distribution isotopic variation and origin of sulfur in coals in the wuda coalfield inner mongolia china abstract this paper describes coal petrographic characteristics sulfur abundance distribution and isotopic signature in coals in the wuda coalfield inner mongolia northern china petrographic studies suggest that depositional environment influences petrographic composition the no 9 and no 10 coal seams which are thought to have formed on a tidal delta plain have high collodetrinite contents up to 66 1 indicating enhanced gelification and bacteria activity during coal accumulation and also have the highest sulfur content 3 46 and 3 42 both organic and pyritic sulfur isotope values 12 3 to 5 8 and 18 7 to 1 1 respectively are variable and generally tend to be more negative in high sulfur coals than those in low sulfur coals in the wuda coalfield the negative sulfur isotope values indicate that a large portion of sulfur in the high sulfur coals has a bacterial origin sulfur isotopic compositions and variations within the section were used to propose a model to explain the origin of sulfur in these coals the presence of pyritized rod like bacteria cyanophyte s gelatinous sheaths and degraded algae organic matter suggests that bacteria and perhaps algae may play an important role in the formation of these high sulfur coals

mineralogy and geochemistry of a superhigh organic sulfur coal yanshan coalfield yunnan china evidence for a volcanic ash component and influence by submarine exhalation abstract the mineralogy and geochemistry of a superhigh organic sulfur shos coal of late permian age from the yanshan coalfield yunnan province southwestern china have been studied using optical microscope low temperature ashing plus x ray diffraction analysis scanning electron microscope equipped with energy dispersive x ray spectrometer a sequential chemical extraction procedure and inductively coupled plasma mass spectrometry the m9 coal from the yanshan coalfield is a shos coal that has a total sulfur content of 10 12 11 30 and an organic sulfur content of 8 77 10 30 the minerals in the coal consist mainly of high temperature quartz sanidine albite muscovite illite pyrite and trace amounts of kaolinite plagioclase akermanite rutile and dawsonite as compared with ordinary worldwide bituminous coals and anthracite and chinese coals the m9 coal is remarkably enriched in b 268 g g f 841 g g v 567 g g cr 329 g g ni 73 9 g g mo 204 g g and u 153 g g in addition elements including se 25 2 g g zr 262 g g nb 20 1 g g cd 2 07 g g and tl 2 03 g g are also enriched in the coal occurrence of high temperature quartz sanidine muscovite and illite in the m9 coal is evidence that there is a volcanic ash component in the coal that was derived from acid volcanic ashes fallen into the swamp during peat accumulation occurrence of albite and dawsonite in the coal and strong enrichment of some elements including f s v cr ni mo and u are attributed to the influence by submarine exhalation which invaded along with seawater into the anoxic peat swamp abundances of lithophile elements including rare earth elements nb y zr and tio2 indicate that the silicate minerals in the coal were derived from the northern vietnam upland to the south of the basin

a downscaling method of topographic index distribution for matching the scales of model application and parameter identification higher resolution topographic information contained in the topographic index of topmodel is lost when digital elevation models dems with a coarse grid resolution are used thus the topographic index is scale dependent demonstrating identified model parameter values to be dependent on dem resolution this makes it difficult to use model parameter values identified through a different resolution of topmodel the inconsistency is the result of the difference between the scale at which the model parameters are identified and the scale at which the model is applied to overcome this problem scale laws that govern the relationship between the resolution of digital elevation data and geomorphometric parameters of the topographic index were analysed and a method to downscale the topographic index distribution developed to account for the difference in scales between model application and parameter identification the method to downscale the topographic index is composed of two ideas one involves introducing a resolution factor to account for the scale effect in upslope catchment area per unit contour length in the topographic index the other utilizes a fractal method through steepest slope scaling to account for the scale effect on slopes this method successfully derived a topographic index distribution of a fine resolution dem by using only a coarse resolution dem the method has been applied successfully to the kamishiiba catchment 210 km 2 in japan and has demonstrated that the downscaled topographic index distribution derived using a 1000 m grid dem is very similar to the topographic index distribution derived via fine target resolution dems the method is then coupled with a topmodel simulation to match the scales of model application and parameter identification it is shown that the simulated runoff from the downscaled topmodel applied at 1000 m resolution of the kamishiiba catchment with the same set of effective parameter values derived from 50 m resolution dem matched the simulated runoff in the 50 m dem resolution topmodel it was also shown that topmodel coupled with the downscaling method of the topographic index accurately simulated runoff for different rainfall events in the catchment without recalibration copyright 2006 john wiley sons ltd

palaeoenvironment of seam i in the marathousa lignite mine megalopolis basin southern greece the present study aims to elucidate the depositional environment of seam i in the megalopolis basin southern greece using existing geological data supported by maceral and mineralogical analyses as well as by natural radioactivity determinations very high pyrite and uranium contents and a very low tissue preservation index usually suggest a marine influence during deposition in seam i however these features are most probably the result of a karstic aquifer supplying the palaeomire with sulphate rich neutral to weakly alkaline water the pyrite formation and the u precipitation are attributed to the anaerobic conditions which prevailed during peat accumulation the petrographic mineralogical and geochemical data of the studied profile point to several changes in the surface runoff and the supply of clastic material during deposition

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

mineralogical and compositional characteristics of late permian coals from an area of high lung cancer rate in xuan wei yunnan china occurrence and origin of quartz and chamosite abstract some townships in xuan wei county yunnan province have one of the highest lung cancer mortality rates in china and the epidemic disease in the area has generally been attributed to the polycyclic aromatic hydrocarbons pahs released from domestic coal burning however the cancer causing culprit is not settled as tian tian l 2005 coal combustion emissions and lung cancer in xuan wei china ph d thesis university of california berkeley found nanometer quartz in these coals soot emissions and lung cancer tissues we have conducted mineralogical and geochemical studies of the coals from xuan wei for the purpose of shedding light on the minerals which may be related to the epidemic lung cancer in this paper abundances modes of occurrence and origins of minerals and elements in the coals from two mines in xuan wei have been studied using optical microscope low temperature ashing x ray diffraction analysis scanning electron microscope equipped with energy dispersive x ray spectrometer and inductively coupled plasma mass spectrometry the minerals in the coals are mainly composed of quartz chamosite kaolinite and calcite the particle size of quartz is rather small mostly less than 20 m and it is of authigenic origin chamosite occurs mainly as cell fillings the occurrence of quartz and chamosite indicates that they were derived from the hydrothermal fluids epigenetic calcite is derived from calcic fluids kaolinite is derived mainly from sediment source region of kangdian oldland to the west of coal basin the composition of xuan wei coal is high in sio2 fe2o3 tio2 cao mno v co ni cu and zn the high sio2 content is attributed to quartz and the fe2o3 content to chamosite the high mn and low mg contents in the coal indicate the inputs of hydrothermal fluids cao occurs mainly in epigenetic calcite elements ti co ni cu zn and rare earth elements were derived from the basaltic rocks at sediment source region

petrology mineralogy and geochemistry of submarine coals and petrified forest in the sozopol bay bulgaria abstract the mineralogy petrology and geochemistry of submarine coals and petrified tree trunks from the sozopol bay were investigated the coals are lignites of lower middle miocene age the petrified trunks are 40 cm up to 2 m high some of which are in growth position and others are fallen the main minerals in the coal are silicates of detrital origin clay minerals and authigenic pyrite authigenic sulfur and amber are present as well in the sozopol coals stored for 30 years a neoformed mineral assemblage comprising mainly of gypsum iron sulfates sulfates of varying fe na al k and mg content and halite has been observed the formation of the sulfates was induced by bacterial activity as well germanium li rb ti v mo cr mn co and ni are enriched in the coals as compared with the clarke values of the world brown coals in most of the samples studied the contents of ga b y w cu zn pb p and zr are elevated as well the element distribution is influenced by the lithotype composition most elements have a mixed mode of occurrence germanium v ti cr b na and ni and to a lesser extent sr and cu are organically associated while k li rb and fe have a distinct inorganic mode of occurrence molybdenum follows strictly the fe distribution it is suggested that the main sources of the trace elements were the volcanic rocks in the sediment source area from which the elements were leached in the peat bog

effects of digital elevation model map scale and data resolution on a topography based watershed model the effects of digital elevation model dem map scale and data resolution on watershed model predictions of hydrologic characteristics were determined for topmodel a topography based watershed model the effects of topography on watershed hydrology are represented in topmodel as the distribution of ln a tan b where ln is the napierian logarithm a is the upslope area per unit contour length and tan b is the gravitational gradient the minimum maximum mean variance and skew values of the ln a tan b distribution were computed from 1 24 000 scale 24k dems at 30 and 90 m resolutions and from 1 250 000 scale 250k dems at 90 m resolution for 71 areas in pennsylvania new york and new jersey an analysis of topmodel showed that model predictions of the depth to the water table the ratio of overland flow to total flow peak flow and variance and skew of predicted streamflow were affected by both the dem map scale and data resolution further topmodel analyses showed that the effects of dem map scale and data resolution on model predictions were due to the sensitivity of the predictions to the mean of the ln a tan b distribution which was affected by both dem map scale and data resolution dem map scale affected the mean of the ln a tan b distribution through its influence on the mean of the ln a distribution which characterizes land surface shape and the mean of ln 1 tan b distribution which characterizes land surface slope dem resolution in contrast affected the mean of the ln a tan b distribution primarily by its influence on the mean of the ln a distribution

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

occurrence and origins of minerals in mixed layer illite smectite rich coals of the late permian age from the changxing mine eastern yunnan china abstract minerals in coals from the changxing mine of eastern yunnan southwestern china were investigated using low temperature ashing plus x ray diffraction lta xrd optical microscopy and scanning electron microscopy with an energy dispersive x ray spectrometer sem edx the results show that minerals in the changxing coals include mixed layer illite smectite i s quartz kaolinite dolomite mg bearing siderite anatase ammonium illite k illite calcite and chamosite as well as minor amounts of hematite paragonite k feldspar and an al hydroxide mineral gibbsite the changxing coals are typically rich in mixed layer i s accounting for an average of 47 2 in their low temperature ashes mixed layer i s occurs mainly in two types 1 lentoid as thin beds and 2 fractures or cells fillings the type 1 is of terrigenous detrital origin and probably related to the weathering products of the emeishan basalt while the type 2 is of epigenetic origin and precipitated from hydrothermal fluids of a mafic magma intrusion the high k and poor na in the type 1 mixed layer i s indicate that it is in a higher evolution stage than the type 2 ammonium illite k illite and paragonite are probably products of dissolution and recrystallization of mixed layer i s while mg bearing siderite and partly chamosite are related to the fe mg al and si released from the evolution of mixed layer i s

geochemistry of late triassic coals in the changhe mine sichuan basin southwestern china evidence for authigenic lanthanide enrichment abstract five thin coals of late triassic age occur in the changhe mine sichuan basin southwestern china petrology and geochemistry of these coals and their roof parting and floor samples were studied the results show that the changhe coals are enriched in as 8 9 11 8 g g w 2 2 11 2 g g pb 20 8 48 2 g g and th 7 5 18 8 g g the source of these elements is possibly the xuefeng old land which is an early paleozoic source area southeast of the sichuan basin two tonsteins were found in the changhe mine one is the roof k8r of the k8 coal which is a pure kaolinitic claystone the other is the claystone k9c above the roof of the k9 coal which is mainly made up of mixed illite smectite minerals the ree content 287 9 g g of the k8 coal is much higher than that of its roof 153 6 g g sem edx results show that authigenic monazite and kaolinite are the main carriers of ree in the k8 coal on the basis of coal chemistry and occurrence of the precipitated minerals it is likely that leaching of the k8r tonstein occurred it is possible that trace elements including be 8 4 g g zr 302 g g nb 26 g g hf 9 7 g g th 18 8 g g u 5 8 g g ga 16 1 g g and pb 48 2 g g in the k8 coal were also elevated by the leachate of its overlying tonstein k8r the k9c tonstein with a total thickness of 16 cm is widely distributed in the changhe mine and serves as a distinct marker bed for correlation of coal seams besides mixed illite smectite minerals trace amounts of euhedral zircon anatase apatite and massive silica with vesicular structure were also examined these constitute strong evidence for its felsic volcanic ash origin

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

organic petrographical mineralogical and geochemical features of the achlada and mavropigi lignite deposits nw macedonia greece abstract the achlada and mavropigi lignite deposits in northern greece provide the main coal source for the next generation of greek power plants a comparative characterization of these two lignite deposits is presented covering the coal rank and the features of the maceral components based on detailed coal petrography and the mineralogical and geochemical features of the coals and their ashes based on xrf and xrd analyses the data are used to interpret the palaeoenvironments of the lignite beds as well as factors that may affect their burnout behavior both deposits have a lignite c rank the mavropigi lignite is mainly a matrix lignite lithotype whereas the achlada deposit consists both of matrix and xylite rich lithotypes the achlada lignite was formed in a fluviatile environment mainly in the abandoned channels of a meandering river system during flooding periods hence it is enriched in inorganic matter with ash values 30 wt the mavropigi lignite formed in a reed marsh environment under limno telmatic conditions and displays ash values the inorganic matter of the two deposits is different in composition due to the contrasting environments and these differences should be taken into account in optimizing their utilization for power production a preliminary assessment indicates that the achlada lignite may have more favorable slagging and fouling properties than the mavropigi lignite although experimental studies are required for more solid conclusions to be reached

re scaling the topographic index to improve the representation of physical processes in catchment models abstract the assignment of hydrological model parameters from physically measurable catchment attributes remains an unsolved problem several authors have shown that for the hydrological model topmodel there is a relationship between the scale of the digital elevation model dem and the saturated hydraulic conductivity parameter used to calculate water table position and baseflow for models that use dem data from pixels measured in tens of metres the value of the corresponding saturated hydraulic conductivities for satisfactory flow reproduction are often much larger than measured values and this causes most surface flow to be generated by the saturation excess mechanism this is undesirable in environments where infiltration excess runoff can also occur this paper presents a way to objectively compensate for the distorting effect of dem scale on the value of the saturated hydraulic conductivity so that its measured value can be used in topmodel simulations the method described links the distribution of topographic index ln a tan to a spatial variability measure svm based on the shannon and weaver information content equation for a digital signal by maximising the svm an optimum adjustment to the mean of the distribution of topographic index can be made so that the distribution represents what would have been calculated had a dem been available at the spatial resolution at which the saturated hydraulic conductivity was measured the method is applied to a topmodel of the mahurangi basin in new zealand and it is shown that physically reasonable simulations are achieved with the adjusted distribution of topographic index

geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the antaibao mining district shanxi china twenty six samples including roof bottom and coal plies of a marine influenced coal bed were collected from the antaibao mining district shanxi china the rare earth elements rees were determined in solids and organic solvent extracts the distribution pattern showed three distinct patterns shale like lree rich and hree rich this is attributed to the variable microenvironment of peat forming swamp the degree of marine influences and different ree sources rees in the coal are mainly controlled by detrital minerals but also affected by seawater the chondrite normalized ree patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples which show a negative eu anomaly a depletion of middle rees and an enrichment of hrees the lrees in coal extracts are likely adsorbed by hydrogen containing functional groups and hrees are likely bonded to carbon atoms

vermicular kaolinite relics in fly ash derived from bokaro and jharia coals jharkhand india abstract during a study of fly ash from two pulverized fuel power plants bokaro and chandrapura burning coal from the bokaro coalfield in jharkand state india glassy and vermicular mineral forms were found associated with the char a combination of optical microscopy xrd sem eds and xrf analysis has shown that this morphotype reported here for the first time originated from kaolinite that expanded during heating inside the furnace chamber under relatively low combustion temperatures the morphotype has an internal structure that resembles the fanning out structure formed during vermicular kaolinite development

chemical weathering controls on variations in the molybdenum isotopic composition of river water evidence from large rivers in china abstract mo isotopic composition in large rivers is very important for understanding global mo cycle at present temporal variation signatures in the 98 95 mo in large rivers have not been investigated which hinder a comprehensive understanding on the mechanism for the variations of mo isotopic compositions in river water in this study we report a one year long time series march 2010 to march 2011 of the 98 95 mo of both the water and suspended particulates collected at guiping from the middle reaches of the xijiang river xjr and of the water 98 95 mo from the lower reaches of the huanghe river hhr or yellow river collected at lijin china the results indicate that the temporal variations in the concentration and 98 95 mo of dissolved mo in the xjr range from 4 32 to 10 5 nmol l mean 7 31 nmol l and 1 04 to 1 31 relative to nist 3134 mean 1 20 respectively but that the particulates have a lower 98 95 mo 0 18 to 0 58 analysis of the suspended particulates and other chemical parameters of the river water suggests that the weathering of silicates and sulfides is the main contributor to the dissolved mo content in the xjr subsequently the highly efficient preferential trapping of lighter 98 95 mo by weathering products such as clay minerals fe mn oxides and organic materials in soils and saprolites which are abundant in the tropical catchment is the key to the heavy mo isotope signatures in the xjr furthermore it seems that neither mo scavenging by suspended particulates during riverine transportation nor the weathering of sulfates significantly influences the 98 95 mo of the xjr water cross comparison among the 98 95 mo in the waters of the three largest rivers in china the changjiang cjr hhr and xjr indicates that the hhr has the highest mo concentrations but the lightest 98 95 mo the xjr has the lowest mo concentrations but the heaviest 98 95 mo and the values for the cjr are intermediate between those for the other two rivers this supports the conclusion that the efficiency of the selective trapping of mo by soils and saprolites is the main factor controlling 98 95 mo in these large rivers the tropical subtropical xjr catchment experiences intense chemical weathering the semi arid temperate hhr catchment experiences very little and the cjr catchment falls somewhere between the two such a relationship between water mo concentrations and 98 95 mo agrees with previous observations from many large rivers worldwide it is therefore suggested that chemical weathering on continents is the key to variations in the isotopic composition of mo in the waters of large rivers

pollen evidence of the palaeoenvironments of lufengpithecus lufengensis in the zhaotong basin southeastern margin of the tibetan plateau evolutionary processes in hominoid primates were closely related to global and or regional environmental changes and therefore palaeoenvironmental reconstruction is fundamental for understanding how environmental changes shaped their evolution here we present pollen data from the 16 m thick shuitangba stb section yunnan province southwestern china bearing remains of the hominoid lufengpithecus lufengensis of the terminal miocene and use principal component analysis to reconstruct the palaeovegetation and palaeodimate during the key period when the hominoid lived our results show that before the stb hominoid appeared zone a the vegetation was dominated by subtropical evergreen broad leaved taxa with a few temperate deciduous taxa e g quercus castanea castanopsis alnus the development of aquatic plants commencing at the similar to 12 m depth is a prominent feature indicating a warm and humid climate during the time when the hominoid lived zone b evergreen broad leaved forests with evergreen quercus were predominant while grasses including poaceae began to expand and simultaneously conifers decreased indicating a warm climate the significant presence of aquatic pollen taxa in subzone a 2 and zone b suggests the occurrence of lacustrine or swampy environments in contrast in zone c the vegetation changed to coniferous forest indicating cooler and drier conditions these results provide substantive evidence of the vegetation conditions when the hominoid lived suggesting that the greater diversity of vegetation and the warm humid climate compared to the present day would have favoured its survival c 2015 elsevier b v all rights reserved

mineralogy and geochemistry of a late permian coal in the dafang coalfield guizhou china influence from siliceous and iron rich calcic hydrothermal fluids abstract this paper describes the influence of siliceous and iron rich calcic low temperature hydrothermal fluids lthf on the mineralogy and geochemistry of the late permian no 11 coal anthracitic r r 2 85 in the dafang coalfield in northwestern guizhou province china the no 11 coal has high contents of vein ankerite 10 2 vol and vein quartz 11 4 vol with formation temperatures of 85 and 180 c respectively indicating that vein ankerite and vein quartz were derived from low temperature calcic and siliceous hydrothermal fluids in two epigenetic episodes the vein quartz appears to have formed earlier than vein ankerite did and at least three distinct stages of ankerite formation with different ca sr and fe mn ratios were observed the two types of mineral veins are sources of different suites of major and trace metals scanning electron microscope and sequential extraction studies show that in addition to fe mg and ca vein ankerite is the dominant source of mn cu ni pb and zn in the coal and the contents of these five elements are as high as 0 09 and 74 0 33 6 185 and 289 g g respectively in contrast vein quartz is the main carrier mineral for platinum group elements pges pd pt and ir in the coal and the contents of pd pt and ir are 1 57 0 15 and 0 007 g g respectively sequential extraction showed a high pge content in the silicate fraction up to 10 4 g g pd 1 23 g g pt and 0 05 g g ir respectively it is concluded that the formation of ankerite and quartz and the anomalous enrichment of trace elements in the no 11 coal in the dafang coalfield guizhou result from the influx of calcic and siliceous low temperature hydrothermal fluids

comparison of single and multiple flow direction algorithms for computing topographic parameters in topmodel single flow direction sfd and multiple flow direction mfd algorithms were used to compute the spatial and statistical distributions of the topographic index used in the watershed model topmodel an sfd algorithm assumes that subsurface flow occurs only in the steepest downslope direction from any given point an mfd algorithm assumes that subsurface flow occurs in all downslope directions from any given point the topographic index in topmodel is in a tan 3 where in is the napierian logarithm a is the upslope area per unit contour length and tan 3 is the slope gradient the in a tan 3 distributions were computed from digital elevation model dem data for locations with diverse topography in arizona colorado louisiana nebraska north carolina oregon pennsylvania tennessee vermont and virginia the means of the in a tan 3 distributions were higher when the mfd algorithm was used for computation compared to when the sfd algorithm was used the variances and skews of the distributions were lower for the mfd algorithm compared to the sfd algorithm the differences between the mfd and sfd algorithms in the mean variance and skew of the in a tan 3 distribution were almost identical for the various dems and were not affected by dem resolution or watershed size topmodel model efficiency and simulated flow paths were affected only slightly when the in a tan 3 distribution was computed with the sfd algorithm instead of the mfd algorithm any difference in the model efficiency and simulated flow paths between the sfd and mfd algorithms essentially disappeared when the model was calibrated by adjusting subsurface hydraulic parameters

chamosite siderite and the environmental conditions of their formation in chamosite type phanerozoic ooidal ironstones abstract two characteristic ironstone minerals occurring in chamosite type ironstone deposits were investigated these are the minerals of the chlorite and the carbonate series the samples are from 31 localities and 8 countries czech republic france germany united kingdom egypt nigeria and usa these deposits are identical to those presented by mucke and farshad mucke a farshad f in press whole rock and mineralogical composition of phanerozoic ooidal ironstones comparison and differentiation of subtypes ore geology reviews with ordovician to late cretaceous ages electron microprobe analyses of 197 carbonates and 64 chlorites were carried out the analytical points of the carbonates in a magnesite calcite siderite rhodochrosite 100 mol diagram are distributed within a limited area close to the siderite end member the area can be subdivided into two fields 1 the carbonates of the ordovician ironstones of the welsh prague and thuringian basins have high siderite concentrations 87 1 to 90 6 mol magnesite contents from 6 7 to 8 3 mol and calcite concentrations from 1 6 to 2 4 mol in the ordovician ironstone of krusna hora prague basin the siderite concentrations are lower 78 3 mol and those of magnesite 15 6 mol and calcite 5 7 mol are higher 2 the carbonates of the other ironstones jurassic to late cretaceous have lower siderite 72 5 to 79 mol and higher magnesite 12 6 to 15 7 mol and calcite 6 9 to 12 2 mol contents the average values of the rhodochrosite end member lie in the range between 0 13 and 2 31 mol and the siderite rhodochrosite ratio 158 on average the analytical points of the chlorite analyses are presented in the fetot mg alvi 100 atom diagram one field containing exclusively chlorites with green internal reflections can be subdivided into two areas one area contains the chlorites of the ordovician ironstones consisting of 62 8 to 77 7 atom fetot 17 5 to 30 9 atom alvi and 4 1 to 7 4 atom mg and the other those of the jurassic to late cretaceous ironstones consisting of 55 7 to 62 5 atom fetot 26 to 33 8 atom alvi and 9 to 13 atom mg the second field contains altered chlorites of ferruginized ironstones aswan and red mountain formation these chlorites present brown internal reflections and have compositions 34 9 to 46 7 atom fetot 24 8 to 42 2 atom alvi and 16 0 to 28 5 atom mg that do not reflect the original diagenetic environment within the al al fe mg mg mg fe atom diagram the chlorite analyses are concentrated in a limited field which is distinctly separated from chlorites formed in other environments the occurrence of carbonate and chlorite both with slightly varying compositions dominated by their iron end members which occur characteristically in association with framboidal pyrite and organic matter are indications that three prerequisites for the formation of the ironstones are comparable in narrow limits these are 1 the composition of the protoliths 2 the depositional environment of the protoliths and their rates of deposition and 3 the environmental conditions that occurred during the lithification of the protoliths due to submarine diagenesis the protoliths consist of mixtures of kaolinite fe3 oxide hydroxide and organic matter the depositional environments are marine basins in which fully marine conditions occur and thus the availability of mg and ca not contained in the protoliths exists the rates of deposition control the amount of mg in the chloritess and that of mg and ca in the carbonatess and the environmental conditions during submarine diagenesis depend on the availability of organic matter creating reducing conditions due to bacterial oxidation the resulting conditions are reducing and depending on the amount of organic matter pass successively from post oxic formation of chamosite and authigenic rice grain shaped siderite via sulphidic formation of framboidal pyrite into methanic formation of abundant xenomorphic siderite that replaces chamosite

mineralogy and geochemistry of the coals from the karmozd and kiasar coal mines mazandaran province iran abstract the karmozd and kiasar mines are two major coal producing areas in the central alborz coal bearing field northern iran this study focused on the mineralogy and geochemistry with respect to the mode of occurrence of elements in feed coals and element partitioning during coal preparation the low sulfur content in the coal seams indicates a non marine origin i e deposition in lacustrine and swamp environments detrital minerals in the coal seams are quartz feldspar albite and orthoclase mica muscovite and biotite amphibole hornblende and kaolinite authigenic minerals include pyrite calcite and chlorite the contents of most elements are within the general worldwide ranges with the exceptions of mn co and cr in some coal seams correlation coefficients between elements and the ash yield identified four separate groups of elements the sequential extraction results indicate that al na k zn cu and co principally occur in the silicates whereas pb and cr mainly occur in the organic fraction calcium and mg display strong affinities to the carbonate phase while cd mainly occurs in the water soluble and organic fractions the calculated removability index shows that the coal cleaning method in zirab not only removes mineral matter and pyritic sulfur but also reduces the content of most inorganic elements

microstructure and composition of brittle faults in claystones of the mont terri rock laboratory switzerland new data from petrographic studies geophysical borehole logging and permeability tests abstract claystones are considered as a geological barrier however the properties of claystone may be modified if these are cut by brittle faults and fractures investigations of fault rocks are therefore crucial to evaluate the barrier properties of clay rich formations the present study is dealing with the characterization of naturally and artificially deformed opalinus clay of the mont terri rock laboratory in nw switzerland complete core sections covering the artificially excavation damaged zone edz and several tectonic fault zones have been studied using a multidisciplinary approach consisting of geophysical geotechnical mineralogical geochemical and lithological structural data the fault zones encountered are characterized by a high density of planar discontinuities which often show slickenside striations under the microscope the fault zones turned out to be pervasively deformed resulting in open veins and pore space now filled with calcite and celestine fault zone reactivation led to very fine grained cohesionless fault gouge and fragmentation of the previously formed calcite veins packer tests in boreholes reveal excavation induced enhanced permeabilities up to 3 m borehole depth 1 9 m to gallery floor seismic borehole measurements indicate that seismic attributes which are typical for undisturbed opalinus clay are not reached until 7 5 m borehole depth 4 8 m to gallery floor which is larger than in the usual gallery configuration we interpret the anomalies in geophysical measurements as well as the elevated permeabilities measured in the main fault 3 6 m to 4 2 m to gallery floor to result from an enlarged edz influenced by the presence of the brittle fault structures the up to two orders of magnitude higher permeability compared to the intact claystone most probably results from excavation induced stress and a local reactivation of fault planes the results suggest that the presence of a fault zone can alter the extent of the edz significantly and thereby affect the rock integrity at least in the near field of a repository tunnel

characteristics of ferrospheres in fly ashes derived from bokaro and jharia jharkand india coals abstract coal burning power plants in the state of jharkand india are facing the problem of fly ash landfilling and their economic and environmental impact however fly ash may be used in civil engineering constructions including as geoliners for municipal wastes landfilling however in this case the groundwater contamination should be taken in consideration in this work a combination of analytical techniques is used to study the nature composition and potential environmental impact of fe bearing morphotypes ferrospheres in fly ash from thermal power plants fed with coals from bokaro and jharia coalfields jharkand india the results show that the feed coals are sulfur poor and ash rich dominated by quartz clays and minor portions of fe bearing carbonates such as siderite pyrite was not identified although iron is present in the fly ashes in significant proportions from 2 7 wt to 4 5 wt equivalent to an fe 2 o 3 content ranging from 3 5 wt to 5 8 wt mineral phases such as magnetite and hematite are only present in minor proportions or below detection limits of the xrd analyses iron in the ferrospheres occurs as massive or dendritic crystals or as finely dispersed crystals trapped inside a glassy aluminosilicate matrix resulting from the release of iron oxide plumes into the aluminosilicate melt in addition to these phases iron also occurs as a component of the glass that makes up most of the fly ash materials finally the contaminant potential of groundwater by the fly ash iron is negligible

effects of catchment discretization on topographic index distributions summary digital elevation models dems are widely used in topographically based hydrology models most researchers dealing with dems have worked exclusively with either grid or contour based techniques intercomparisons of these techniques are empirical in nature few in number and limited to a small number of catchments we examine the relative effects of these techniques on the distribution of the topographic index ti for nine idealised hillslope types and eight natural catchments 4 4 83 km 2 in southeast australia in particular we investigate the underlying causes for the frequently observed increase in the ti with grid size a simple analytical model for a parallel planar hillslope indicates that median ti is asymptotic with respect to the number of grid cells and a linear function of grid size we demonstrate that the latter result holds for hillslopes with more complex geometry using a multiple flow direction algorithm we find that hillslope geometry and flow partitioning affect the spatial pattern of the ti and the rate of change m of median ti with grid size this makes it impractical to recommend general guidelines for the value of the directional parameter in flow partitioning algorithms for the natural catchments we show that median ti is also a linear function of grid size and that there is some evidence for a linear relationship between m and the inverse of the median topographic slope throughout the investigation we find that contour dems are less sensitive to changes in resolution than grid dems

clays in natural and engineered barriers for radioactive waste confinement an introduction the concept of engineered geological disposal has been developed for the safe long term management of long lived radioactive waste this involves emplacement of radioactive waste in deep geological repositories that contain and isolate the waste and consequently protect humans and the environment the multiple barrier concept is the cornerstone of all proposed schemes for the geological disposal of radioactive waste based on the principle that uncertainties in performance can be minimized by conservatism in design the concept invokes a series of complementary barriers both engineered and natural geological between the waste and the surface environment each successive barrier represents an additional impediment to the movement of radionuclides regarding engineered barriers for lowand intermediate level waste the waste may be incorporated in a relatively stable and inert matrix such as cement bitumen lead alloy or polymer resin the choice varying depending on the waste management organization glass may be used in the case of certain high level reprocessing wastes owing to the very low leach rate of glass in groundwater vitrification is widely accepted to be one of the best methods of immobilizing the aqueous products from the reprocessing of spent fuel many waste containers will provide some form of physical barrier to groundwater however because of the relatively small volumes of waste involved spent fuel vitrified waste and other highly active wastes will be totally encapsulated in corrosion resistant metal canisters that are designed to prevent groundwater entry for extended time periods in excess of 100 000 years depending on the disposal concept engineered barriers may comprise the buffer backfill medium enclosing the waste containers the tunnel borehole liner and the backfill and high integrity seals placed in the repository access ways or emplacement boreholes the buffer backfill medium enclosing the waste will often also provide both a physical and a chemical barrier to radionuclide migration the functions of the engineered chemical barriers are to reduce the rate of corrosion of the waste containers and thus extend their life to limit the rate of hydraulic transport to limit the release of radionuclides from the waste form to the far field geosphere after container failure to limit the migration of radionuclides along the pathway provided by the access tunnels and shafts of a repository or the boreholes in the case of a deep borehole emplacement

cleat filling calcite in illinois basin coals trace element evidence for meteoric fluid migration in a coal basin the microdistribution of mn 786 to 9480 ppm sr 5 to 461 ppm and fe 52 to 16 700 ppm was determined for cleat filling calcites in the herrin springfield and colchester coals using focussed synchrotron radiation compositional zonation in the calcites reflects a multistage history of precipitation from fluids with differing trace element characteristics in nearly all of the samples a high fe geq sim 5000 ppm calcite is the latest composition to form replacing earlier stages with varying but generally lower fe contents partitioning data for sr suggest that a typical calcite with 200 ppm sr formed from a fluid with a sr ca of about 0 005 this sr ca is 4 times lower than seawater and 12 times lower than the average for present day illinois basin saline formation waters formation of cleat filling calcite is best explained by precipitation from fluids similar to present day dilute shallow formation waters having a meteoric source

measurement of in situ stress in weak rocks at mont terri rock laboratory switzerland in situ stress measurements in weak rocks such as clay shales that respond strongly to environmental changes are particularly difficult an extensive in situ stress measurement program has been conducted at the mont terri rock laboratory in northwestern switzerland hydraulic fracturing undercoring around a 600 mm diameter borehole using csiro triaxial strain cells and the borehole slotter were used to establish the state of stress for the opalinus clay at this location conflicting orientations and magnitudes resulted from the measurement programs three dimensional elastic modelling was used in conjunction with tunnel and borehole observations to establish the most likely stress tensor a stress measurement program using a borehole deformation gauge is currently underway to check the stress tensor resulting from the observational modelling

a new type of nb ta zr hf ree ga polymetallic deposit in the late permian coal bearing strata eastern yunnan southwestern china possible economic significance and genetic implications abstract this paper describes a new type of nb ta zr hf ree ga polymetallic deposit of volcanic origin in the late permian coal bearing strata of eastern yunnan southwestern china well logging data especially natural gamma ray geochemical data high concentrations of nb ta zr hf ree and ga and mineralogical compositions nb ta zr hf or ree bearing minerals rarely observed together with the volcanic lithological characteristics indicate that there are thick 1 10 m mostly 2 5 m ore beds in the lower xuanwei formation late permian in eastern yunann of southwestern china the ore beds are highly enriched in nb ta 2 o 5 302 627 ppm zr hf o 2 3805 8468 ppm ree oxides of la lu y 1216 1358 ppm and ga 52 4 81 3 ppm the ore beds are mainly composed of quartz mixed layer illite smectite kaolinite berthierine and albite four types of ore beds in the study area were identified namely clay altered volcanic ash tuffaceous clay tuff and volcanic breccia preliminary studies suggest that the high concentrations of otherwise rare metals were mainly derived from the alkalic pyroclastic rocks the modes of occurrence spatial distribution and enrichment mechanism of the rare metals however require further study

flow structures and mineralisation in thermally altered coal from the moatize basin mozambique abstract this paper examines changes in structural and petrographic characteristics of organic and inorganic matter developed in a cored 35 m thick permian coal seam from the moatize basin mozambique in proximity to an early jurassic intrusive igneous body megascopic and microscopic examinations of hand samples and polished blocks respectively were carried out to characterise the deformation and petrographic changes of the coal sem eds analysis was used for mineral identification and modes of occurrence the upper part of the core is thermally altered exhibiting intense megascopic folding of the bedding at microscopic level vitrinite presents an incipient mosaic coke texture semi coke whereas fusinite and semifusinite layers are deformed exhibiting folded structures coal petrographic characteristics suggests the temperature in the coal at this location reached no higher than 400 c but was enough for softening and ductile deformation of bands to occur apart from epigenetic chamosite occurring exclusively in the upper section and monazite that appears only in the lower section of the core microscopic studies showed similar distribution of the mineral species in both sections of the seam except with a change in their mode of occurrence detrital or syngenetic minerals in the lower section of the seam occur also as epigenetic in the thermally affected upper section siderite occurs as syngenetic nodules in the lower section but appears as epigenetic fracture filling developed with the cooling of the organic material in the upper section quartz occurs as detrital grains in the lower section whereas in the upper section this mineral occurs also as an epigenetic euhedral mineral filling the fracture system fluorapatite occurs as detrital syngenetic and euhedral epigenetic the mineralisation in the fractures also gives indications about the fluid circulation associated with the magmatic intrusion at least three stages of hydrothermal fluids were distinguished from the first to the last stage a p f and si rich fluid an fe ca mg rich fluid and an al si rich fluid these fluids gave origin to the minerals in the fractures and to some of the minerals inside the cell lumina of the inertinite macerals given the euhedral shape of some of the epigenetic minerals there was sufficient time for them to grow into euhedral forms

drainage networks from grid digital elevation models current algorithms that deduce the drainage network from a digital elevation model dem represented by a regular array of surface elevations share a fault unless the terrain is rugged the derived water channels tend to flow in parallel lines along preferred directions engendered by the sampling grid orientation we present a simple solution to the problem a second difficulty is the presence of noise that creates artificial pits we briefly describe a method which deals with pits in what we believe to be a more efficient manner for virtual memory environments than previous efforts our system has treated dems of nearly 9 000 000 pixels we show how depth first search of the resulting drainage network permits segmentation of the dem into basins by various criteria analysis of stream sediment anomaly dilution profiles improved hydrological models and other applications

provenance and tectonic implications of the 3 28 3 23 ga fig tree group central barberton greenstone belt south africa abstract sedimentary rocks provide a valuable record of non uniformitarian paleoarchean tectonic processes the rocks of the 3 28 3 23 ga mapepe formation mark the initiation of orogenesis in the barberton greenstone belt south africa however reconstruction of the mapepe basin s is challenging because the rocks occur in fault bounded structural belts that are characterized by lateral heterogeneity and whose correlation remains uncertain we have studied the petrography geochemistry and detrital zircon geochronology from outcrop and drill core samples from two adjacent structural belts the manzimnyama syncline and the eastern barite valley area to evaluate the timing of basin formation correlate between these two adjacent areas and provide constraints on the character of tectonic uplift in the eastern barite valley area sedimentation was initiated at about 3260 ma the section includes a lower deep water unit of mainly mudstone overlain by a shoaling upward sequence of fan delta sandstone and conglomerate the sandstone throughout the formation was derived by erosion of local uplifts of the underlying greenstone belt sequence except at the top of the section where sedimentation was dominated by dacitic volcaniclastic sediments dated at 3239 ma in contrast rocks of the mapepe formation in the manzimnyama syncline area 1 2 km south of the eastern barite valley area record the initiation of sedimentation at about 3277 ma with deposition of a rhyolitic tuffaceous unit followed by persistent deep water sedimentation of banded iron formation banded ferruginous chert and turbiditic sandstone siliciclastic sediments are immature and were derived by erosion of older supracrustal greenstone belt rocks no fig tree age volcanism younger than 3260 ma is recorded in this belt overall mapepe sedimentary rocks record the formation of numerous local uplifts of underlying supracrustal rocks with periodic volcanic activity and the dispersal of debris to form mainly small fan deltas flanked by deep water systems the contrasting ages lithologies depositional settings and provenance of the sedimentary rocks in the now adjacent eastern barite valley and manzimnyama syncline belts suggest that they were deposited in either different parts of a large complex fig tree basin or represent separate basins that have been juxtaposed during post fig tree tectonism and shortening

digital elevation model networks demon a model of flow over hillslopes for computation of contributing and dispersal areas current algorithms for computing contributing areas from a rectangular grid digital elevation model dem use the flow routing model of o callaghan and mark 1984 which has two major restrictions 1 flow which originates over a two dimensional pixel is treated as a point source nondimensional and is projected downslope by a line one dimensional moore and grayson 1991 and 2 the flow direction in each pixel is restricted to eight possibilities we show that large errors in the computed contributing areas result for any terrain topography divergent convergent or planar we present a new model called digital elevation model networks demon which avoids the above problems by representing flow in two dimensions and directed by aspect demon allows computation of both contributing and dispersal areas demon offers the main advantage of contour based models e g moore et al 1988 the representation of varying flow width over nonplanar topography while having the convenience of using rectangular grid dems

the information content theory for the estimation of the topographic index distribution used in topmodel this paper analyses the significance of the entropy concept in the topography parameterization within the model topmodel proposed by beven and kirkby 1979 by means of the hydrological behaviour of an experimental basin in southern italy for a significant number of flood events recorded at the basin outlet the performance of topmodel for different spatial distributions of the topographic index ln a tan has been observed performance is related to the information content estimated as an entropy measure corresponding to each of the spatial distributions of the topographic index with the aim of identifying the procedures most suitable to represent the hydrological process of rainfall runoff the results obtained have shown that for flood events corresponding to brief heavy precipitation some procedures provide better performances than others moreover these improvements are justified by greater information content in the corresponding spatial distributions of the topographic index finally topmodel performances for some procedures have been analysed varying the resolution scale of the topographic index for analogous hydrological performances scale change produced variations in some of the subsurface hydraulic parameters these variations were proportional to a spatial variability measure of the topographic index distribution derived from the corresponding information content 1997 john wiley sons ltd

the prediction of hillslope flow paths for distributed hydrological modelling using digital terrain models the accuracy of the predictions of distributed hydrological models must depend in part on the proper specification of flow pathways this paper examines some of the problems of deriving flow pathways from raster digital terrain data in the context of hydrological predictions using topmodel distributed moisture status is predicted in topmodel on the basis of spatial indices that depend on flow path definition the sensitivity of this index to flow path algorithm and grid size is examined for the case where the surface topography is a good indicator of local hydraulic gradients a strategy for the case where downslope subsurface flow pathways may deviate from those indicated by the surface topography is described with an example application

ferruginous seawater facilitates the transformation of glauconite to chamosite an example from the mesoproterozoic xiamaling formation of north china berthierine and chamosite are iron rich clay minerals that share similar chemical compositions berthierine forms at low temperature 25 45 c during early diagenesis and may transfer to chamosite at temperatures of 70 c because the formation of berthierine and chamosite requires significant amount of fe 2 supply their presence in marine sediments is often used as a mineral proxy for ferruginous conditions in porewater recent studies reveal that the precambrian oceans were characterized by pervasive ferruginous water column conditions that may favor the formation of iron rich clay minerals like berthierine and chamosite to evaluate if ferruginous water column conditions in the precambrian ocean played a role on iron rich clay mineral formation we conducted an integrated petrographic mineralogical and geochemical study on the chamosite and glauconite bearing strata of the mesoproterozoic xiamaling formation 1 40 1 35 ga in north china petrographic xrd sem and eds analyses show that the chamosites of the xiamaling formation was transferred from glauconite with berthierine as an intermediate mineral phase during early diagenesis geochemical analyses indicate that a complete transformation from glauconite dominated to chamosite dominated end members samples requires an addition of a large amount of fe 16 9 wt mg 2 4 wt and a small amount of al 1 4 wt but a simultaneous release of si 11 8 wt and k 6 0 wt considering that the glauconite and chamosite bearing strata are devoid of iron rich detrital minerals e g biotite and iron oxides and lack evidence of hydrothermal alteration the required fe 2 for glauconite berthierine chamosite transformation was most likely from fe 2 rich ferruginous seawater which may have promoted glauconite berthierine transformation at the very early diagenetic stage when fe 2 exchange between porewater and seawater was still available this interpretation is consistent with the high fe hr fe t but low fe py fe hr fe al and v al ratios from the hosting strata that support ferruginous depositional environments because most precambrian strata have passed the oil window temperature 50 150 c the preservation of berthierine would be rare and chamosite should be the representative iron rich clay mineral thus the abundance of chamosite in fine grained marine siliciclastic sediments may be used as a mineral indicator of ferruginous water column conditions

quantitative characterization of the excavation damaged zone fracture network in the meuse haute marne underground research laboratory in situ experiment and numerical interpretation of helium injection test