energy release and heat generation during the 1999 ms7 6 chi chi taiwan earthquake 1 on 20 september 1999 the ms7 6 chi chi earthquake ruptured the chelungpu fault in central taiwan integrating observed and inversed results of source parameters the fracture energy eg and frictional energy ef on the fault and its northern and southern segments are estimated together with given values of strain energy e and seismic radiation energy es the seismic efficiency i e es e and the radiation efficiency i e r es es eg are evaluated the average fracture energy per unit area g is also calculated from eg the frictional heat caused by dynamic frictional stress is calculated from ef results show a marked difference in source properties between the two segments the average frictional and ambient stress levels on the two segments are estimated the total energy budget of and heat generated by the earthquake are elucidated based on a two dimensional faulting model with frictional heat both observed and calculated results suggest the possible existence of fluids which produced suprahydrostatic gradients on the fault during faulting lubrication and thermal fluid pressurization might play a significant role on rupture

effect of thermal pressurization on radiation efficiency abstract the radiation efficiency r is an important parameter showing the source property it is strongly affected by the variation in shear stress with slip thermal pressurization is considered to be a significant mechanism in controlling such a variation thus influencing r in this study the formula of r as a function of slip on the basis of two end member models of thermal pressurization that is the adiabatic undrained deformation aud model and slip on a plane sop model proposed by rice 2006 is derived the controlling parameters of the aud and sop models are respectively c and l which are dependent on thermal mechanical and hydraulic parameters of fault rocks modeled results suggest that thermal pressurization controls the variation in shear stress with slip and thus influences the radiation efficiency results show that r increases with the increasing rate of r with is high at small and low at large this indicates that r varies very much with for small earthquakes and only slightly depends on for large events for the two end member models r increases with decreasing c or l when c l r is higher for the aud model than for the sop model the thermal pressurization model is also applied to investigate the shear stress slip function in a 5 5 km square covering a drilled site on the fault plane of the 1999 chi chi taiwan earthquake inferred from seismograms results show that the aod model is more appropriate to describe the inferred shear stress slip function than the sop model and the proposed model is a modified one from the aud model by including a small amount of loss of frictional heat from the slip zone during faulting

impact of co combustion of petroleum coke and coal on fly ash quality case study of a western kentucky power plant abstract petroleum coke has been used as a supplement or replacement for coal in pulverized fuel combustion at a 444 mw western kentucky power station the combustion of nearly 60 petroleum coke with moderate to high sulfur illinois basin coal produces fly ash with nearly 50 uncombusted petroleum coke and large amounts of v and ni when compared to fly ash from strictly pulverized coal burns partitioning of the v and ni known from other studies to be concentrated in petroleum coke was noted however the distribution of v and ni does not directly correspond to the amount of uncombusted petroleum coke in the fly ash vanadium and ni are preferentially associated with the finer higher surface area fly ash fractions captured at lower flue gas temperatures the presence of uncombusted petroleum coke in the fly ash doubles the amount of ash to be disposed makes the fly ash unmarketable because of the high c content and would lead to higher than typical compared to other fly ashes in the region concentrations of v and ni in the fly ash even if the petroleum coke c could be beneficiated from the fly ash further studies of co combustion ashes are necessary in order to understand their behavior in disposal

a mineralogical and geochemical study of three brazilian coal cleaning rejects demonstration of electron beam applications abstract the background and anthropogenic levels of hazardous elements in the surface soil of a coal mining area depend on the geological setting of the region and the underlying soil material but may also be influenced by water borne or aeolian transport of sediment from adjacent coal related waste piles very few studies have focused on the chemical and mineralogical composition of brazilian coal cleaning rejects ccrs which may represent significant sources of soil or water contamination in this study we have investigated the quantitative distribution of minerals and potentially hazardous elements in ccrs and a run of mine coal from the brazilian states of rio grande do sul and santa catarina the major minerals identified by x ray diffraction xrd high resolution transmission electron microscopy hr tem and field emission scanning electron microscopy energy dispersive x ray analysis techniques fe sem eds are kaolinite quartz mixed layer illite smectite pyrite jarosite melanterite gypsum rutile and calcite while minor minerals include barite hematite siderite sphalerite and goethite galena magnetite zircon and many other species may also occur as accessory trace minerals pyrite and jarosite are relatively abundant in some cases making up to around 4 or 5 of the mineral matter with jarosite melanterite and gypsum probably formed by complex interaction of oxidation products from fe sulfides and clay or carbonate components initiated by exposure and storage of the host material such atmospheric exposure promotes sulfide oxidation that releases substantial sulfate loads as well as ca 2 k mg 2 cl and al 3 metals with the most severe discharges were zn cu mn co ni and cd most of the trace pollutants in the ccrs displayed a ph dependent solubility being immobile in near neutral samples but mobile under the low ph conditions associated with oxidized material the results highlight the complex interactions among mineral matter components of the ccrs during storage and the potential for release of potentially hazardous elements in association with longer term exposure and storage

origin and significance of high nickel and chromium concentrations in pliocene lignite of the kosovo basin serbia abstract trace element data from 59 pliocene lignite cores from the lignite field in the kosovo basin southern serbia show localized enrichment of ni and cr 33 304 ppm and 8 176 ppm respectively whole coal basis concentrations of both elements decrease from the western and southern boundaries of the lignite field low temperature ash and polished coal pellets of selected bench and whole coal samples were analyzed by x ray diffraction and scanning electron microscopy with energy dispersive x ray analyses these analyses show that most of the ni and cr are incorporated in detrital and to a lesser degree in authigenic minerals the ni and cr bearing detrital minerals include oxides chromites serpentine group minerals and rare mixed layer clays possible authigenic minerals include ni fe sulfates and sulfides analyses of three lignite samples by a supercritical fluid extraction technique indicate that some 1 11 of the ni is organically bound ni and cr bearing oxides mixed layer clays chromites and serpentine group minerals were also identified in weathered and fresh samples of laterite developed on serpentinized paleozoic peridotite at the nearby glavica and cikatovo ni mines these mines are located along the western and northwestern rim respectively of the kosovo basin where ni contents are highest the detrital ni and cr bearing minerals identified in lignite samples from the western part of the kosovo basin may have been transported into the paleoswamp by rivers that drained the two paleocene laterites some ni may have been transported directly into the paleoswamp in solution or alternatively ni may have been leached from detrital minerals by acidic peat water and adsorbed onto organic matter and included into authigenic mineral phases no minable source of ni and cr is known in the southern part of the lignite field however the mineral and chemical data from the lignite and associated rocks suggest that such a source area may exist

a theory for strong long lived squall lines abstract we study herein the mechanics of long lived line oriented precipitating cumulus convection squall lines using two and three dimensional numerical models of moist convection these models used in juxtaposition enable us to address the important theoretical issue of whether a squall line is a system of special long lived cells or whether it is a long lived system of ordinary short lived cells our review of the observational literature indicates that the latter is the most consistent paradigm for the vast majority of cases but on occasion a squall line may be composed of essentially steady supercell thunderstorms the numerical experiments presented herein show that either type of squall line may develop from an initial line like disturbance depending on the magnitude and orientation of the environmental shear with respect to the line with shallow shear oriented perpendicular to the line a long lived line evolves containing individually short lived cells our analysis of this type o

rupture histories of eastern north american earthquakes abstract digital worldwide records of p and sh waves are used to invert for rupture histories of the recent larger eastern north american earthquakes the data include a broad bandwidth to facilitate recovery of both source details and total moment the following events are studied 9 january 1982 new brunswick 5 october and 23 december 1985 nahanni 25 november 1988 saguenay and 25 december 1989 ungava earthquakes we employ a finite fault waveform inversion scheme that discretizes the slip history as a function of position on the fault this formulation allows estimation of rise time and slip velocity in addition to the spatial distribution of slip static stress drops averaged over the entire rupture surface range from a few tens of bars to just over 100 bars and are similar to values estimated for western united states earthquakes estimates of stress drop for spatially limited asperities are in the range of a few hundred bars with the value for the saguenay earthquake asperity being the largest approaching 1 kbar the variation in stress drop is considerable but no evidence is seen for a scaling relation in which stress drop increases with moment maximum slip velocities on the fault also have a wide range from 50 cm sec to perhaps greater then 200 cm sec with the saguenay and 5 october nahanni earthquakes lying at the upper end of this range of the events studied the saguenay earthquake is unique in terms of its greater depth spatially concentrated source and large asperity stress drop

geochemistry of beryllium in bulgarian coals abstract the beryllium content of about 3000 samples coal coaly shales partings coal lithotypes and isolated coalified woods from 16 bulgarian coal deposits was determined by atomic emission spectrography mean be concentrations in coal show great variability from 0 9 to 35 ppm for the deposits studied there was no clear cut relationship between be content and rank the following mean and confidence interval be values were measured lignites 2 6 0 8 ppm sub bituminous coals 8 2 3 3 ppm bituminous coals 3 0 1 2 ppm and anthracites 19 9 0 ppm the be contents in coal and coaly shales for all deposits correlated positively suggesting a common source of the element many samples of the coal lithotypes vitrain and xylain proved to be richer in be than the hosting whole coal samples as compared on ash basis up to tenfold increase in be levels was routinely recorded in fusain the ash of all isolated coalified woods was found to contain 1 1 to 50 times higher be content relative to its global median value for coal inclusions indirect evidence shows that be occurs in both organic and inorganic forms beryllium is predominantly organically bound in deposits with enhanced be content whereas the inorganic form prevails in deposits whose be concentration approximates clarke values the enrichment in be exceeding the coal clarke value 2 4 to 14 5 times in some of the bulgarian deposits is attributed to subsynchronous at the time of coal deposition hydrothermal and volcanic activity

mobility of trace and potentially harmful elements in the environment from high sulfur indian coal mines abstract coal mine rejects and sulfide bearing coals are prone to acid mine drainage amd formation due to aqueous weathering these acidic effluents contain dissolved trace and potentially harmful elements phes that have considerable impact on the environment the behavior of these elements in amd is mainly controlled by ph the focus of the present study is to investigate aqueous leaching of mine rejects for prediction of acid producing potential rates of weathering and release of phes in mine drainage mine reject mr and coal samples from the active mine sites of meghalaya india typically have high s contents 1 8 5 7 in mr and 1 7 4 7 in coals with 75 90 of the s in organic form and enrichment of most of the phes in rejects aqueous kinetic leaching experiments on mine rejects showed high acid producing potential and release of trace and potentially harmful elements the elements sb as cd cr co cu pb mn ni v and zn in mine sample leachates are compared with those in mine waters the concentrations of al si p k ti mn fe co ni cu zn and pb are found to increase with leaching time and are negatively correlated with ph of the solution the processes controlling the release of these elements are acid leaching precipitation and adsorption the critical loads of phes in water affected by amd are calculated by comparing their concentrations with those of regulatory levels the enrichment factors efs and soil pollution indices spis for the elements have shown that phes from coal and mine reject samples are mobilized into the nearby environment and are enriched in the associated soil and sediment

1999 chi chi earthquake a case study on the role of thrust ramp structures for generating earthquakes the 21 september 1999 chi chi earthquake m w 7 6 occurred on east dipping shallow thrust faults that produced a high relief surface rupture extraordinary surface breaks appeared that could be clearly traced for about 100 km across many counties these thrust faults the chelungpu and shihkang are part of an active fold and thrust belt related to ongoing recent arc continent collision measurement of slip vectors along the earthquake rupture indicates that the orientation of the maximum shear stress changed from a westward direction n70 90 w on the chelungpu fault to a northwestward direction n30 40 w on the shihkang fault the stress field underwent a clockwise rotation of about 40 during the chi chi earthquake near rupture vertical displacements in the hanging wall of the shihkang fault have more cumulative displacement than on the chelungpu fault which is consistent with global positioning system gps measurements maximum vertical offset on the rupture was found to be about 10 m by the surficial rupture and gps measurements in addition analysis of crustal deformation by gps measurements on the hanging wall defines a coseismic uplift related to a fault ramp structure our synthesis of geological and geodetic analyses shows the importance of ramp structures associated with thrust faults for generating large earthquakes and provides a general framework for understanding earthquake in fold and thrust belts large surficial coseismic uplift and strong asperities appear to be a function of fault ramp geometry our analysis also indicates that in general ramp structures in fold and thrust belts may have a high potential in generating large earthquakes manuscript received 14 november 2000

mississippian anthracites in guangxi province southern china petrological mineralogical and rare earth element evidence for high temperature solutions abstract minerals and elements in coal are derived from the processes associated with peat accumulation and rank advance as well as possibly a range of epigenetic processes and thus can provide information on the depositional conditions and geologic history of coal beds and coal bearing sequences as well as perhaps on regional tectonics this paper investigates the petrology mineralogy and geochemistry of anthracites and their host rocks partings roof and floor strata from two coal deposits hongmao and luocheng in guangxi province southern china samples collected from these deposits were analyzed using optical microscopy scanning electron microscopy plus energy dispersive x ray spectrometry low temperature ashing x ray diffraction x ray fluorescence spectrometry and quadrupole based inductively coupled plasma mass spectrometry the anthracites from the two deposits are medium to high sulfur coals the rare earth elements in the luocheng anthracites are characterized by distinct positive eu anomalies and medium and heavy ree enrichment types the minerals in the hongmao anthracites are characterized by the occurrence of k illite paragonite and ammonian illite which however are absent in the luocheng anthracites the paragonite ammonian illite and chlorite resulted from the alteration of pre existing kaolinite by hot solutions containing na nh4 and fe2 respectively the partings in the luocheng anthracite seams contain pyrophyllite that was formed by reactions between kaolinite and quartz during injection of high temperature solutions the mineralogical and geochemical characteristics of the anthracites in the two deposits indicate that the coals were subjected to high temperature 250 c solutions that also elevated the coal rank to anthracite grade the assemblage of k illite paragonite nh4 illite in the coals of the hongmao deposit was formed under greater hydrothermal but less tectonic influence compared to the luocheng deposit by contrast the pyrophyllite illite chlorite assemblage of the luocheng deposit reflects a greater tectonic but lesser hydrothermal influence

structure and evolution of winter cyclones in the central united states and their effects on the distribution of precipitation part i a synoptic scale rainband associated with a dryline and lee trough abstract a convective rainband which was approximately 1500 km in length and affected large areas of the central united states for about 16 h developed within an evolving winter cyclone the rainband which will be referred to as the pre drytrough rainband formed approximately 400 km ahead of a developing dryline and lee trough drytrough for short that created an elevated sloping layer of convective instability the presence of a deep pool of high potential temperature air in the middle troposphere over the south central united states advected there from the elevated terrain to the southwest i e an elevated mixed layer produced a region of warm air advection downstream of the high terrain this enhanced the lifting associated with a migrating short wave aloft and generated the pre drytrough rainband in previous studies the dryline the lee trough the elevated mixed layer and the low level jet in the central united states have generally been viewed as isolated features here the authors pre

surface convergence induced by cold fronts aloft and prefrontal surges abstract the magnitude of surface convergence produced by the movement of cold fronts aloft and prefrontal surges is derived by applying the linear divergence equation to observed surface pressure traces for pacific northwest warm occlusions and from a mesoscale model simulation of a warm occlusion like structure in the central united states convergence values of approximately 10 4 s 1 are found to be generated locally for periods of about 1 h yielding vertical displacements of 10 50 hpa it is hypothesized that such convergences should noticeably enhance condensation rates in the widespread lower stratiform clouds associated with warm occlusions and could be a key mechanism for the triggering of squall lines by cold fronts aloft in cyclones in the central united states

static stress drop inferred from near fault parameters for the 1999 chi chi earthquake in taiwan abstract in 2001 a special issue of the bulletin of the seismological society of america bssa featured seismological research for the 1999 chi chi taiwan earthquake this study uses source parameters suggested by the first author in this special issue to estimate static stress drop associated with the chi chi earthquake the waveform simulation method was used to carefully examine these source parameters the simulation results indicate that source parameters inferred from near fault observations are well determined according to the rupture area and slip the static stress drops s obtained were distributed between a small value of 47 bars near the epicentral region and a much larger value 200 bars to the north similar trends in dynamic stress drop d were also recognized by the first author in his paper published in 2001 bssa special issue comparing the s with d satisfies the relation s d 1 this relation suggests that fault motion is mostly spent releasing seismic wave energy during the rupture process of the chi chi earthquake the consistency between static and dynamic stress drops thus provides a measure of energy moment es m0 ratios which range from 9 0 10 5 to 6 5 10 4 the average es m0 ratio estimated for the northern portions of the fault is 3 4 10 4 which is about 3 times that of the south such a high es m0 ratio can be interpreted as having low strength in the rupture for the northern portions of the fault where the fault would release less energy per unit rupture surface to create the new rupture

geochemical systematics and precious metal content of the sedimentary horizons of lower gondwanas from the sattupalli coal field godavari valley india abstract major trace rare earth ree and platinum group elements pge have been analysed from the carbonaceous horizons of permian barakar formation of sattupalli coal field of godavari valley to understand the provenance and depositional environment barakar formation of coal field consists of sandstone siltstone carbonaceous shale and coal seams coal is enriched in trace elements compared with the clarke s background values ferromagnesian trace elements ni cr and co are similar in range in both coal and carbonaceous shales along with large ion lithophile elements lile rb sr cs and ba high field strength elements hfse nb ta zr and ti light ree lree la sm and ag archean upper crust auc normalized ree and multielement variation patterns of the coal show a flat ree with a slight depletion in ce and eu contents in most of the samples their multielement patterns exhibit enrichment of th and u negative ta zr hf and positive ti anomalies pronounced positive anomaly occurs at zr hf and ti that are combined with both positive and negative nb and ta anomalies in carbonaceous shales and clay sandstones have a high sio 2 50 80 wt low fe 2 o 3 al 2 o 3 and moderately high k 2 o contents auc normalized ree patterns are almost flat with slight negative to no eu anomalies followed by small negative ce anomalies ce ce 0 87 0 95 with one exception their multielement patterns exhibit positive u small negative nb ta a pronounced positive zr hf anomaly followed by negative ti and v anomalies enrichment of both zr and tio 2 in some samples reflects on the mafic and felsic sources at the source region the fractionated ree patterns hree enrichment and negative eu anomalies are consistent with contribution of zircon through felsic source nb ta troughs endorse their inheritance from schistose rocks of eastern ghats complex the high al 2 o 3 yb and th yb ratios along with negative eu anomalies reflect on the ttg felsic rocks of provenance based on the geochemical available petrological and paleocurrent analysis indicate the source rocks of the barakar formation were granite granitic gneiss high grade metamorphic rocks from eastern ghats and basic rocks the provenance is located west and south east i e partly peninsular gneiss and partly eastern ghat complex the au pge contents of sattupalli coalfield have been deposited through ne sw trending post depositional transverse faults that have affected all the gondwana formations during the early cretaceous the mafic rocks present within the basement could have been the source of these elements

determination of earthquake energy release and ml using terrascope we estimated the energy radiated by earthquakes in southern california using on scale very broadband recordings from terrascope the method we used involves time integration of the squared ground motion velocity and empirical determination of the distance attenuation function and the station corrections the time integral is typically taken over a duration of 2 min after the p wave arrival the attenuation curve for the energy integral we obtained is given by q r cr n exp kr r 2 2 h ref 2 with c 0 49710 n 1 0322 k 0 0035 km 1 and h ref 8 km where is the epicentral distance a similar method was used to determine m l using terrascope data the station corrections for m l are determined such that the m l values determined from terrascope agree with those from the traditional optical wood anderson seismographs for 1 5 6 5 m l saturates the ratio e s m 0 m 0 seismic moment a measure of the average stress drop for six earthquakes the 1989 montebello earthquake m l 4 6 the 1989 pasadena earthquake m l 4 9 the 1990 upland earthquake m l 5 2 the 1991 sierra madre earthquake m l 5 8 the 1992 joshua tree earthquake m l 6 1 and the 1992 landers earthquake m w 7 3 are about 10 times larger than those of the others that include the aftershocks of the 1987 whittier narrows earthquake the sierra madre earthquake the joshua tree earthquake and the two earthquakes on the san jacinto fault the difference in the stress drop between the mainshock and their large aftershocks may be similar to that between earthquakes on a fault with long and short repeat times the aftershocks which occurred on the fault plane where the mainshock slippage occurred had a very short time to heal hence a low stress drop the repeat time of the major earthquakes on the frontal fault systems in the transverse ranges in southern california is believed to be very long a few thousand years hence the events in the transverse ranges may have higher stress drops than those of the events occurring on faults with shorter repeat times such as the san andreas fault and the san jacinto fault the observation that very high stress drop events occur in the transverse ranges and the los angeles basin has important implications for the regional seismic potential the occurrence of these high stress drop events near the bottom of the seismogenic zone strongly suggests that these fault systems are capable of supporting high stress that will eventually be released in major seismic events characterization of earthquakes in terms of the e s m 0 ratio using broadband data will help delineate the spatial distribution of seismogenic stresses in the los angeles basin and the transverse ranges

reconnaissance study of mineral matter and trace elements in greek lignites abstract mineral matter in low temperature ashes major oxides and trace elements were determined for twenty eight selected lignite samples and their respective 1000 c ashes from various locations in greece using x ray diffraction x ray fluorescence spectroscopy and inaa lignites ashed at lower temperature 150 c reveal the presence of quartz feldspars layer silicates pyrite gypsum bassanite and anhydrite in all samples in northwestern greece epirus kozani florina and ptolemais calcite siderite magnesite epsomite hexahydrite jarosite and meta aluminite coexist with the common occurring minerals large variation in the concentration of major constituents in the 1000 c ashes is observed sio 2 varies from 11 98 to 87 72 al 2 o 3 from 4 53 to 23 36 fe 2 o 3 from 3 01 to 39 72 cao from 0 55 to 43 05 mgo from 0 18 to 9 17 and so 3 from 0 02 to 32 72 smaller variations are exhibited by tio 2 na 2 o k 2 o and p 2 o 5 these variations are attributed to the depositional environment high concentrations of pb 548 ppm zn 2991 ppm ba 1520 ppm as 1131 and 1675 ppm mo 565 and 712 ppm w 191 420 ppm and sb 69 ppm are reported in the 1000 c ashes of the selected lignites from serres and drama northern greece samples from another location in northern greece serres yield 5000 ppm u while in drama dipotama u concentration reaches as high as 17 600 ppm the u enrichment of lignites in these locations is attributed to the leaching of this element from the superimposed u bearing volcanic rhyodacitic rocks of oligocene age in southern greece peloponnesus lignite samples from megalopolis xidias drossato and vounargo show high f ranging from 154 to 218 ppm present results indicate that not only the wide variety and combination of elements that can be used to fingerprint lignitic basins but also the possibility of extracting such valuable elements from lignites and their ashes whenever the concentration and economics warrants such an undertaking

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

strain drop and apparent strain for large earthquakes abstract kikuchi m 1992 strain drop and apparent strain for large earthquakes in t mikumo k aki m ohnaka l j ruff and p k p spudich editors earthquake source physics and earthquake precursors tectonophysics 211 107 113 two kinds of strains are considered the strain drop 2 and the apparent average strain the latter is given by the ratio between the secismic wave energy and the seismic moment e s m o these two kinds of strains are related as e s m o e 2 where e is a phenomenological constant which coincides with the seismic efficiency if the final stress across a fault plane is equal to zero e is also interpreted in terms of a frictional sliding model using the values estimated from the inversion of long period waves for large earthquakes a diagram of e s m o versus 2 is constructed it is shown that the value of e is in general as small as 0 1 a systematic discrepancy can be seen among three groups a shallow inland strike slip event b ocean bottom dip slip event c deep focus event the value of e for c is smaller than that for a and b suggesting that deep focus events are associated with a different slip characteristics than shallow events on the other hand the strain drop for b is smaller than that for a and c indicating that the strain drop for intra plate earthquakes is larger than that for inter plate earthquakes

mineralogical and geochemical characterization of the saray and pinarhisar coals northwest thrace basin turkey abstract this study investigates the mineralogical and geochemical characteristics of coals from the saray and pinarhisar coalfields in the northwest thrace basin using optical microscopy scanning electron microscopy x ray diffraction and inductively coupled plasma mass spectrometry the saray and pinarhisar coals were deposited in a limnic environment the sulfur content of the coals ranges from 0 3 to 15 3 and high sulfur contents may originate from both seawater and volcanism pyritic and organic sulfur are the dominant sulfur forms 1 2 and 2 7 on average respectively the mineral matter of the coals consists mainly of pyrite barite gypsum muscovite and kaolinite with minor amounts of quartz butlerite tamarugite and rozenite the coals are enriched in trace elements including v 61 ppm on average co 5 85 ppm on average ni 79 ppm on average as 39 2 ppm on average th 3 6 ppm on average and u 6 7 ppm on average based on pearson correlation coefficients ti v cr fe co ni cu se rb au hg pb and th have mainly inorganic affinities r ash elements 0 5 in the pinarhisar coals fe as and au also have inorganic affinities r ash elements 0 5 in the saray coals the element contents and correlation coefficients indicate that the strandja massif the tethyan ophiolite belt and the oldest basement sediments were included in the sediment source region for both coalfields while the strandja massif was the prevailing sediment source region for pinarhisar coalfield

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

structure and evolution of winter cyclones in the central united states and their effects on the distribution of precipitation part ii arctic fronts abstract the structure and evolution of a shallow but intense cold front commonly referred to as an arctic front and its associated precipitation features that passed through the central united states from 0000 utc 9 march to 0000 utc 10 march 1992 are studied with the aid of observations and outputs from a numerical simulation using the pennsylvania state university national center for atmospheric research mesoscale model mm4 located above the arctic front was a region of midtropospheric frontogenetical confluence that was attended by a thermally direct vertical circulation a large banded precipitation feature for the most part located behind the arctic front was produced by ice crystals from upper level clouds formed by the frontogenetical confluence falling into low level stratocumulus associated with the arctic front the arctic front at the surface separated a region where the precipitation reaching the ground was solid from an adjacent region where the precipitation was liquid a westward m

geochemistry of sulfur and elements in coals from the antaibao surface mine pingshuo shanxi province china abstract coal bearing strata in the antaibao surface mine pingshuo mining district shanxi china occur in the taiyuan formation upper carboniferous and shanxi formation lower permian the most productive coal seams in the mine are the nos 11 9 and 4 twenty five samples of coals partings and roof shales from the nos 11 10 9 5 taiyuan formation and 4 shanxi formation seams in the antaibao mine were analyzed for ash and total sulfur contents and forms of sulfur the no 11 seam is a medium to high sulfur coal 1 3 3 1 s a coal sample 14 1 ash from the no 10 seam contains 3 4 and high ash coal 37 4 ash from the same seam contains only 0 4 total sulfur the no 9 seam is a low to medium sulfur coal 0 6 1 3 s the highest sulfur content among the samples is 5 8 total sulfur from a coal sample of the no 5 seam the no 4 seam is low sulfur coal 0 29 0 54 s the remarkable variation in sulfur content among the coal seams in the taiyuan and shanxi formations could reflect different depositional environments from coastal to lower deltaic plain for the taiyuan and from upper deltaic plain to fluvial basin for the shanxi formation the sulfate sulfur comes mainly from the oxidation of pyrite sixteen samples were analyzed for 26 major minor and trace elements by x ray fluorescence spectrometry the sr content is significantly higher in coals from the no 4 seam in the shanxi formation than those from nos 11 to 5 seams chlorine sr ca and p are elements bound organically while si al ti fe k na mg cr v ni rb ba and nb are mainly associated with minerals

distribution of arsenic in coals of yunnan province china and its controlling factors abstract the as concentration and its distribution patterns in southwestern chinese coal beds of two of the most important coal forming periods late permian and neogene are analyzed more than 700 samples from 26 mining districts have been collected and tested for as concentration the as content and distribution in coal can be significantly changed by the combined effects of many factors including the geochemistry of the source region and the tectonic and depositional environment of the basin and surrounding paleo watershed the as distribution in neogene coals of yunnan province reflects to some extent their primary distribution patterns during peat accumulation because as is a sulphophile element two as distribution types can be distinguished based on the correlation coefficient between as and total s contents in the high rank permian coals especially those affected by hydrothermal and tectonic activities significant secondary as enrichment in coal is likely to occur thus to optimally utilize coal resources it is important to investigate the distribution occurrence and concentration of as in coal during resource exploration and evaluation to identify as rich zones in the coal beds

the 1999 taiwan earthquake a proposed stress focusing heel shaped model stress focusing in a proposed heel shaped model reasonably explains the occurrence of the largest onland earthquake m w 7 6 in taiwan9s history the epicenter of the mainshock was located in a low seismicity block where historically large earthquakes have not been documented for the past century spatial variations in crustal deformation reported in global positioning system surveys suggest that the crustal strength in the low seismicity block was stronger than in the surrounding area since the low seismicity block which roughly coincides with the northern part of the peikang high is defined by a convex curve stress partitioning or reorientation might well have taken place along the convex boundary it then likely stored a lot of strain energy before eventually failing the low seismicity block with strong crust characteristics was finally overcome by stress focusing resulting in the generation of the 921 chi chi earthquake near the focus of the low seismicity block where a cluster of earthquakes had occasionally occurred during the past decade significant surface ruptures with vertical offset ranging from 2 to 8 m primarily along the chelungpu fault were restricted to within the low seismicity block in short when a low seismicity block with small velocity fields of crustal deformation is identified in an active foreland belt there should be a greater risk of a larger earthquake to release energy that accumulates in the strong crust this finding provides some useful insight with which to evaluate potential earthquakes in taiwan and other convergent zones

enrichment of arsenic lead and antimony in balingian coal from sarawak malaysia modes of occurrence origin and partitioning behaviour during coal combustion abstract the concentrations of mineral forming elements and trace elements in coal and coal ashes from balingian coalfield sarawak malaysia were assayed and their modes of occurrence enrichment origin and partitioning behaviour during coal combustion were studied as well balingian coal is high in as cu pb sb th and zn of particular concern are as as high as 181 ppm pb 325 ppm and sb 96 ppm all of which are highly enriched in balingian coal relative to their respective coal clarke values arsenic pb and sb in the coal are mostly organic and to a lesser extent they are bound to discrete minerals in the form of aluminosilicates during coal combustion in the power plant a substantial portion of organically associated as pb and sb in the coal vaporize and are released into the atmosphere whereas ba and mn are highly enriched in the coal ashes as compared to the raw coal the as pb and sb anomalies observed in balingian coal may be related to a large sb as and probably pb mineralization in the vicinity of the coalfield with some localised epigenetic infiltration of these elements from the surrounding rocks by circulating groundwaters

coal combustion by product quality at two stoker boilers coal source vs fly ash collection system design fly ashes from two stoker boilers burning pennsylvanian eastern kentucky high volatile a bituminous coal blends were examined for their petrology and chemistry the source coals have similar trace element contents one of the ash collection systems was retrofitted with a baghouse fabric filter system collecting a finer fly ash at a cooler flue gas temperature than the plant that has not been reconfigured the baghouse ash has a markedly higher trace element content than the coarser fly ash from the other plant the enhanced trace element content is most notable in the as concentration reaching nearly 9000 ppm ash basis for one of the collection units differences in the ash chemistry are not due to any substantial differences in the coal source even though the coal sources were from different counties and from different coal beds but rather to the improved pollution control system in the steam plant with the higher trace element contents

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

geochemistry of trace elements in the kesan coal and its effect on the physicochemical features of ground and surface waters in the coal fields edirne thrace region turkey abstract in this study concentration and origin of trace elements of the kesan coals in edirne thrace basin have been investigated in order to determine possible environmental impacts on water pollution the coal ground and surface waters and clay samples were taken from the coal mining area the concentration of trace elements in 14 coal ashes 15 water samples and seven clays was determined by inductively coupled plasma mass spectrometry additionally 11 of these coal samples were studied by proximate and seven coal samples were also studied by x ray diffraction analyses the mineralogical composition of the studied coal samples is made up mainly of quartz clay minerals feldspar group minerals pyrite and amorphous matter the kesan coal ash samples have higher average concentrations of cr 180 ppm ni 192 ppm rb 91 ppm and sr 1701 ppm average values of other trace elements are lower than the world average of brown coal ashes the sulfur content of the kesan coals ranges from 0 4 to 3 90 2 02 on average the ph values of the waters vary between 6 55 and 8 36 in coal fields 7 21 and 7 54 in springs the f cl no 3 so 4 ca mg na and k values of the waters vary between 0 11 and 0 25 mg l 33 49 and 52 90 mg l 0 05 and 59 27 mg l 85 and 2829 mg l 66 and 349 mg l 64 and 222 mg l 41 and 1187 mg l 2 and 13 mg l respectively in coal fields some elements are anomalous in concentrations in some water samples e g cr up to 49 6 ppb mn up to 1185 ppb fe up to 10 352 ppb ni up to 55 8 ppb as up to 9 7 ppb ppb it has been interpreted that the lower trace element concentrations in the water samples may be due to clay intercalated with coal the clays are smectite type and they are enriched in cr co ni as sr and th e g up to 394 ppm cr up to 305 ppm ni and up to 35 5 ppm as

high chromium contents in tertiary coal deposits of northwestern washington a key to their depositional history abstract chromium contents obtained from 20 coal and 5 associated rock samples collected from the basal part of the eocene chuckanut formation in skagit and whatcom counties northwest washington range between 30 and 300 ppm mean 120 ppm whole coal basis the lenticular coals ranging in rank from subbituminous to anthracite and with an ash content of 12 46 crop out along the western flank of the cascade range results of x ray diffraction analysis of low temperature ash show that the mineral matter in the coal samples consists predominantly of quartz and clay kaolinite illite and chlorite group however accessory minerals isolated from the coal samples and analyzed by x ray diffraction scanning electron microscope and optical methods contain angular fragments and euhedral crystals of the spinel group chromite magnetite and trevorite kaolinite serpentine group antigorite and chrysotile chlorite group amphibole group and pyroxene group minerals augite diopside and enstatite all of which are commonly enriched in chromium although associated primarily with the inorganic fraction of the coal concentrations of chromium in the samples show no statistically significant correlation with ash content localized concentrations of chromium in the coal are the result of natural contamination from the alteration of detrital chromium bearing mineral grains introduced into the peat forming mires from nearby jurassic ophiolite bodies the coals formed in the early eocene in rapidly subsiding small basins that developed during the uplift and erosion of the pre tertiary ophiolite terrain scattered bodies of source rock random distribution of chromium bearing minerals within the coal and sample heterogeneity account for the variation in cr contents of the samples

fault rupture process of the 20 september 1999 chi chi taiwan earthquake we modeled the source rupture process of the 20 september 1999 chi chi taiwan earthquake mw 7 6 using an integrated dataset of near field strong ground motion and global positioning system observations this large inland thrust earthquake produced a surface break more than 80 km long along the chelungpu fault the event triggered over 700 strong motion instruments on the island of tai wan this large ground motion dataset provides the best opportunity to date to un derstand earthquake source processes in a major earthquake first we develop a 3d curved fault model consistent with the surface rupture data and aftershock distribu tion the subsurface fault plane has an average dip of 30 to the east and measures 96 km along strike and 40 km down dip next we applied a genetic algorithm to reconstruct the source rupture process the inversion results indicate a complex slip distribution with a generally broad triangular shaped slip zone that points down dip most of the displacement occurred over a 15 km depth range in the northern segment of the fault with the maximum slip exceeding 20 m the average slip is 3 8 m and the average rupture velocity is 2 6 km sec the mainshock slip distribution clearly complements the aftershock location distribution slip rise times range from 8 to 6 sec over most of the primary slip area and decrease slightly as rupture propagates south to north this relatively long rise time resulted in a low dynamic stress drop and low peak ground accelerations observed at surface stations the rake angle rotates across the rupture plane from predominantly dip slip in the southern segment to mostly left lateral oblique slip in the north we find that geometrical irregularities over the fault plane played an important role in controlling the temporal rupture behavior at fault bends rupture tends to decelerate the rake angle rotates to a near dip slip orientation and the shear stress increases as rupture tries to overcome the bending barriers the total seismic moment from our inversion is 2 9 10 27 dyne cm in good agreement with the harvard and the u s geological survey moment estimation

partitioning of elements and macerals during preparation of antaibao coal abstract analyses of the macerals ash sulfur and 43 major and trace elements were performed on samples of feed coal cleaned coal middlings and slime collected from the antaibao coal preparation plant china and also on samples from coal preparation experiments this study is focused on the partitioning of elements and macerals during coal preparation and potential environment aspects of the elements the conclusions are as follows 1 in comparison with the feed coal the cleaned coal has a higher vitrinite content and relatively lower inertinite and exinite contents whereas the middlings and slime have lower vitrinite and exinite contents and relatively higher inertinite contents the vitrinite contents in the size segregated cleaned coals were observed to show a slightly increasing tendency with increasing particle size while the inertinite contents decreased 2 physical coal cleaning is not only effective for removal of ash and sulfur but also in reducing the concentration of most elements as cd co cs hg fe k mg nb and ni are observed to show a high degree of removal while br be cu u mn zn and organic sulfur are enriched in the cleaned coal and show a lower degree of removal the large sized cleaned coal is cleaner than the smaller sized fractions 3 the middlings especially the slime are enriched in s hg cr v zn etc so that these fractions should not be directly used as fuel in addition the concentration of pb and v in the process water exceeds the limit of relevant environmental water quality standard consequently it is necessary to develop new processes to remove ash sulfur and hazardous trace elements to the maximum extent further studies on deep processing of the middlings and slime and cleaning of the process water should also be performed

preseismic deformation and coseismic displacements associated with the 1999 chi chi taiwan earthquake the destructive 1999 chi chi taiwan earthquake m w 7 5 produced an approximately 100 km long surface rupture mostly along the previously recognized north south trending chelungpu fault preseismic deformation in central taiwan is realized from annually repeated global positioning system gps data acquired during the 1992 1999 period the total wnw ese shortening rate in the vicinity of the epicentral region that is from the west coast to the western boundary of the central range is up to 25 mm yr the crustal deformation before the chi chi earthquake was essentially a uniaxial compressional strain of 0 36 strain yr in the direction of 114 the gps measurements taken 0 2 2 7 yr before and within 3 months after the mainshock were utilized to estimate the coseismic displacements horizontal movements of 1 1 9 1 m in the nw nnw directions are observed on the hanging wall eastern side of the fault there is a northward increasing trend in the magnitude of the displacement vectors and a dramatic change in the direction of about 50 toward the east along the fault strike in contrast much smaller se see movements of 0 1 1 5 m are found on the footwall western side of the fault the gps data show 2 4 10 1 m of total horizontal offsets across the chelungpu fault vertical offsets of 1 2 4 4 m with the eastern side up are also observed along the surface rupture the uplift on the hanging wall decreases rapidly toward the east it becomes subsidence at sun moon lake and in the puli wushe area the stations on the footwall show subsidence of 0 02 0 26 m the width of the uplift zone increases from about 10 km in the south to approximately 30 km in the north manuscript received 13 october 2000

estimates of source parameters for the 1999 chi chi taiwan earthquake based on brune s source model the general features of the rupture of the 1999 chi chi taiwan earthquake m s 7 6 can be explained by the displacement waveforms derived from the accelerograms recorded at short distances from the fault traces applying brune s model we have determined important source parameters such as rise time stress drop offset and particle velocity generally the earthquake is characterized as having had two distinct fault segments the southern segment dominated by thrust motion started from the focus on a fault plane raking at 78 and extended about 30 km to the north the northern segment dominated by thrust with significant strike slip motion began next to the end of the southern segment on a fault plane raking at 53 and extended northward for 25 km slips in the southern segment were followed by a small dislocation 1 m while those in the northern segment were followed by a much larger dislocation 9 m the average slip velocity was distributed at 34 49 cm sec along the southern segment and an unusual slip velocity exceeding 2 m sec was observed along the northern segment furthermore the southern segment experienced a rise time of 1 8 sec and a stress drop of 65 bars in contrast to a rise time longer than 4 sec and a stress drop larger than 300 bars registered to the north our results also indicate that along the southern segment the rupture propagated northward at an average velocity of 2 84 km sec but along the northern segment the rate declined to less than 2 km sec the difference in the source parameters between these two segments suggests that the rupturing associated with the chi chi earthquake may have encountered a resistive patch and changed course in the middle part of the fault after crushing that resistance the long rise time and high stress drop probably caused substantially slower motion and larger slip along the northern segment manuscript received 10 november 2000

a preliminary study on the enrichment mechanism and occurrence of hazardous trace elements in the tertiary lignite from the shenbei coalfield china abstract the cr and ni contents are high in the eocene lignite of the shenbei coalfield which is a small intracontinental basin located in liaoning province china in this paper we studied the distribution origin and occurrence of cr ni and other hazardous trace elements in the shenbei lignite on the basis of coal petrology and geochemistry of the lignite and combustion products the following conclusions on the shenbei lignite can be drawn 1 the dominant maceral group in the shenbei coal is huminite humodetrinite accounting for 96 99 of the total maceral inertinite content is less than 1 liptinite content sporinite and cutinite is 0 2 1 6 common minerals in the shenbei lignite include clay minerals kaolinite pyrite and quartz and calcite and siderite chromite is not present in the lignite 2 potentially hazardous trace elements such as co 22 g g cr 79 g g cu 63 g g zn 93 g g v 88 g g and ni 75 g g are strongly enriched in the shenbei lignite compared with average concentration of trace elements in the chinese coal and worldwide lignite these elements are mainly associated with fulvic acid fa and or coal organic macromolecular compounds in most of the studied lignite samples indicating an organic association and enrichment of these elements in the shenbei lignite 3 unusually high trace elements contents in the shenbei lignite are derived mainly from the olivine basalt country rock of coal basin that consists of 52 7 plagioclase 17 8 pyroxene 14 olivine and 15 5 ti fe oxide minerals these olivine basalts have higher cr ni pb and zn contents than other types of rock and worldwide basalts do 4 fly ash of the shenbei lignite with 90 1 50 m amorphous particles and 8 1 10 m cenosphere has high contents of zn 23 707 g g be 12 g g sr 1574 g g pb 486 g g and cr 349 g g in particular the ferruginous micro cenoshperes contain 1 12 79 zn fine bottom ash

evidence for fault lubrication during the 1999 chi chi taiwan earthquake mw7 6 the ground motion data of the 1999 chi chi taiwan earthquake exhibit a striking difference in frequency content between the north and south portions of the rupture zone in the north the ground motion is dominated by large low frequency displacements with relatively small high frequency accelerations the pattern is opposite in the south with smaller displacements and larger accelerations we analyze the fault dynamics in light of a fault lubrication mechanism using near field seismograms and a detailed rupture model the fault zone contains viscous material e g gouge in which pressure increases following the reynolds lubrication equation when the displacement exceeds a threshold lubrication pressure becomes high enough to widen the gap thereby reducing the area of asperity contact with less asperity contact the fault slips more smoothly suppressing high frequency radiation

concentration and distribution of elements in late permian coals from western guizhou province china abstract with the aim of better understanding geochemistry of coal 71 late permian whole seam coal channel samples from western guizhou province southwest china were studied and 57 elements in them were determined the contents of al ca co cr cu fe ga hf k li mn mo nb ni sn ta ti th u v zr and rees in the late permian coals from western guizhou province are higher than the arithmetic means for the corresponding elements in the us coals whereas as ba br f hg p se and tl are lower compared to common chinese coals the contents of co cr cu ga hf li mn mo ni sc sn ti u v zn and zr in western guizhou coals are higher and as f hg rb sb tl and w are lower five groups of elements may be classified according to their mode of occurrence in coal the first two group a tm yb lu y er ho dy tb ce la nd pr gd sm and group b as sr k rb ba f ash si sn ga hf al ta zr be th na have high positive correlation coefficients with ash yield and they show mainly inorganic affinity some elements from group b such as ba be ga hf and th are also characterized by significant aluminosilicate affinity in addition arsenic also exhibits high sulfide affinity r s fe 0 5 the elements which have negative or lower positive correlation coefficients with ash yield with exceptions of bi cs nb mn se and ti are grouped in other four associations group c cr v mo u cd tl group d hg li sc ti eu nb cs w group e bi sb and group f co ni cu pb zn mg se ca mn s fe the correlation coefficients of some elements including co cr cu fe hg li mo ni p s sc u v and zn with ash yield are below the statistically significant value only cr and cu are negatively correlated to ash yield 0 07 and 0 01 respectively showing intermediate organic and inorganic affinity manganese and fe are characterized by carbonate affinity probably due to high content of epigenetic veined ankerite in some coals phosphorus has low correlation coefficients with any other elements and is not included in these six associations there are five possible genetic types of enrichment of elements in coal from western guizhou province source rock volcanic ash low temperature hydrothermal fluid groundwater and magmatic hydrothermal inputs

concentration distribution and modes of occurrence of selenium in huaibei coalfield anhui province china selenium a toxic element is highly enriched in the coals of the huaibei coal deposit china for this study se content along with rock forming and trace element abundances was determined in 123 coal and 19 rock samples collected from the main coal seams in seven coal mines in the huaibei coalfield this was done to investigate the se geochemistry in the huaibei coals compared with average chinese coal and other coals around the world the huaibei coals are enriched in se by a factor of five differences in the boron content in the sequence of huaibei coal seams show that the depositional environment of the formations hosting the coal seams evolved from a delta front to a prodelta setting and then to a delta plain environment selenium is distributed unevenly both horizontally and vertically in the huaibei coal deposit pearson correlation coefficients between se with several elements ca fe and s indicate that iron bearing clay minerals and carbonates are the dominant carriers of se in coals of the lower shihezi formation selenium in coals from no 3 and no 10 coal seams are mainly associated with sulfide minerals the well developed faults in huaibei coalfield may have contributed to the enrichment of se in huaibei coals