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

factors controlling geochemical and mineralogical compositions of coals preserved within marine carbonate successions a case study from the heshan coalfield southern china abstract the late permian coals in the heshan coalfield of southern china are preserved within marine carbonate successions and characterized by super high organic sulfur 5 13 10 82 minerals identified in the coals include quartz kaolinite illite mixed layer illite smectite albite pyrite marcasite calcite and dolomite along with trace amounts of smectite fluorite strontianite rey bearing carbonate minerals jarosite and water bearing fe oxysulfate the coals are very rich in trace elements including f up to 3362 g g v up to 270 g g se up to 24 4 g g mo up to 142 g g u up to 111 g g and to a lesser extent sr y zr nb cd cs heavy rare earth elements hf ta w hg and th previous studies attributed the high organic sulfur and elevated trace elements to the seawater influence or the formation of soil horizons before the accumulation of peat in the basin however mineralogical and geochemical data presented in this study have shown that the sediment source region and multi stage hydrothermal fluids are the dominant influences on the mineralogical composition and elevated trace elements in the coal although seawater influence also contributed to the composition of the mineral matter for example a large proportion of the quartz and clay minerals as well as almost all the albite in both the coal benches and the parting mudstones were derived from detrital materials of terrigenous origin in the yunkai upland high concentrations of lithophile trace elements were also derived from the sediment source region minerals including fluorite calcite dolomite strontianite and rey bearing carbonate minerals were derived from multi stage hydrothermal activities high concentrations of v mo and u that occur through the coal seam sections were probably derived from hydrothermal solutions during peat accumulation or at the early diagenetic stages the hydrothermal fluids also corroded the syngenetically formed minerals quartz albite and pyrite and caused re distribution of lithophile elements from partings to the underlying coal benches resulting in higher key element ratios yb la nb ta and zr hf and more abundant heavy rare earth elements in the coal benches than in the immediately overlying partings

late permian age of nh4 bearing illite in anthracite from eastern pennsylvania temporal limits on coalification in the central appalachians authigenic nh 4 bearing illites in coal fractures from the anthracite region of eastern pennsylvania yield individual k ar dates of 236 253 ma 8 m y and a composite isochron of 253 ma 8 m y rb sr data for the same samples indicate an isochron of 260 ma 44 m y consistent with the more precise k ar data the age of nh 4 bearing illite authigenesis should reflect the time at which coal attained anthracite rank because mineralogical and geochemicai evidence indicates that nh 4 bearing illite formed exclusively during anthracite formation t 200 275 c from organically derived nitrogen and a kaolinite precursor similar late permian k ar dates for both nh 4 rich illite and k illite in anthracite fractures and lack of correlation between percent nh 4 substitution in illite and the k ar date suggest that nh 4 does not influence significantly the closure temperature of illite and thus that nh 4 rich illite can be used for dating the time of authigenesis given the uncertainties in closure temperatures for illite as well as the maximum temperatures for anthracite formation we consider the oldest k ar date of 253 ma 8 m y to be a minimum age for nh 4 illite authigenesis and anthracite formation based on the retention of a detrital age signature in the re examination of syn and post folding secondary chemical remanent magnetizations in rocks from the central appalachians indicates a late early to late permian age 260 250 ma for alleghanian deformation in the vicinity of the anthracite region the age of folding is similar to the 265 255 ma age range for anthracite formation interpreted from illite dates and is consistent with previous studies of vitrinite reflectance fabrics in coal which indicate that anthracite formation occurred prior to and during folding thus age data in conjunction with paleomagnetic and vitrinite reflectance data allow a time period of 25 35 m y for anthracite formation and alleghanian deformation beginning after deposition of the coal in late pennsylvanian or early permian time ca 290 280 ma and concluding by the late permian time ca 260 250 ma significantly longer than previous estimates of less than 15 m y for this thermal tectonic event

mineralogy of the pennsylvanian coal seam in the datanhao mine daqingshan coalfield inner mongolia china genetic implications for mineral matter in coal deposited in an intermontane basin abstract this paper deals with the mineral matter in the coal and associated strata from the datanhao mine daqingshan coalfield which is closely located to the previously reported adaohai and hailiushu mines of the same coalfield the coal from the datanhao mine is mainly high ash and low sulfur bituminous the mineral assemblage in the coal is dominated by quartz kaolinite with varying proportions of carbonates calcite ankerite and siderite small proportions of muscovite illite pyrite and anatase the associated non coal claystone samples have similar mineral assemblage except that most non coal samples contains less quartz than the adjacent coal plies although deposited in the same intermontane basin of the orogenic belt the yinshan upland the datanhao coal seam shows different mineralogical characteristics from those of the nearby adaohai and hailiushu mines this may reflect the different sediment source regions during the peat accumulation stage the sediment source for the datanhao coal was probably the ordovician quartz rich sandstone or the sinan quartzite in the surrounding sub uplifts high proportions of quartz in the datanhao coal suggest intense terrigenous input into the paleomire and a short distance from the sediment source region different mineralogical characteristics of the coals from the three mines datanhao hailiushu and adaohai of the daqingshan coalfield are probably due to the different source material in their respective surrounding subuplifts within the intermontane basin kaolinite displaying graupen tabular and vermicular textures and the common presence of quartz in the intra seam non coal bands from the datanhao coal seam indicate that most of these bands are tonsteins altered airborne volcanic ash the original magma is probably high level volatile rich silicic in composition

nitrogen isotope geochemistry of organic matter and minerals during diagenesis and hydrocarbon migration the magnitude of isotopic variations between organic and inorganic nitrogen was examined in samples from three stacked hydrocarbon reservoirs in the fordoche field louisiana gulf coast basin usa measurements were made of 15n in kerogen bitumen oil formation water and fixed nh4 extracted from mudstones nonproductive sandstones and productive sandstones nitrogen isotope fractionation occurs because 14n is released preferentially to 15n from organic molecules during thermal maturation released 14n goes into solution or may be adsorbed by minerals leaving crude oil enriched in 15n diagenetic clay minerals e g illite commonly form in the temperature range of hydrocarbon generation and nh4 may be fixed in clay interlayers with an isotopic ratio similar to that of the migrating fluids results indicate that the influence of organic matter on mineral 15n depends on the timing of authigenic mineral formation relative to fluid migration the average 15n of kerogen 3 2 0 3 and fixed nh4 from mudstones 3 0 1 4 is similar while bitumen increases from 3 5 to 5 1 with depth in deep reservoir sandstones 100 c the 15n of crude oil averages 5 2 0 4 similar to the 15n of bitumen in the proposed source rocks formation waters are 14n enriched with an average 15n of 2 2 2 6 fixed nh4 15n values lie between that of the oil and water the average 15n of fixed nh4 is 3 0 1 2 in productive sandstones and 0 2 2 4 innonproductive sandstones in the shallower reservoir sandstones 90 c fixed nh4 is apparently not influenced by the presently associated fluids productive and nonproductive sandstones have distinctly low average 15n values 1 2 0 8 yet crude oil 11 1 0 3 and water 3 8 0 1 have been 15n enriched by 6 relative to the deeper reservoirs this suggests that the present fluids migrated into the reservoir after authigenic illite had formed fluids become enriched in 15n during migration and the amount of enrichment may be a function of the amount of interaction with argillaceous sediments

stratigraphic control of hot fluids on anthracitization lackawanna synclinorium pennsylvania abstract the lackawanna synclinorium of pennsylvania contains abundant coal that was altered to anthracite rank during the late paleozoic alleghanian orogeny why did the coal in the synclinorium undergo anthracitization two alternatives have been suggested 1 the region was buried deeply during and or after the alleghanian orogeny and thus became hot in response to earth s geothermal gradient and 2 hot fluids migrating from the orogen toward the foreland carried heat into the coal and caused anthracitization if the second hypothesis is correct the region should contain evidence that hot fluids passed through the coal field observations illite crystallinity studies and fluid inclusion analyses indicate that the coal bearing pottsville and llewellyn formations and an underlying detachment fault called the pottchunk fault at or slightly below the base of the pottsville formation acted as a regional aquifer for the migration of hot fluids during the alleghanian orogeny the presence of quartz veins and the hydrothermal minerals tosudite and pyrophyllite in strata above the pottchunk fault and the apparent absence of an illite crystallinity burial gradient in the underlying strata suggest that fluids migrated through large pores in coarse grained sandstones through abundant fractures that developed in response to alleghanian deformation and along the pottchunk fault the quartz veins tosudite and pyrophyllite mineralization do not occur below the pottchunk fault except at one locality suggesting that fluid flow was greater above the fault perhaps because fracturing accompanying deformation increased permeability of the fault s hanging wall fluid inclusions in the pottsville and llewellyn formations indicate fluids achieved a minimum temperature of 270 c at a depth of 3 1 8 5 km heat flow calculations constrained by fluid inclusion data show the heat carried by the migrating fluids through the coal bearing strata was sufficient to elevate the rock temperature to anthracite grade conditions 250 c assuming that the fluid event lasted about 1 year thus deep burial 6 9 km of the coal bearing strata in the lackawanna synclinorium was not required for anthracitization anthracitization was likely the result of stratigraphically controlled hot fluid migration through the coal bearing strata at shallow depths 5 km

palaeoenvironment and palaeoclimate during the late carboniferous early permian in northern china from carbon and nitrogen isotopes of coals abstract coupling carbon and nitrogen isotopes and petrography of coals and related intra seam carbonaceous mudstone partings from basins in northern china provides insight into regional palaeoenvironments and palaeoclimate during the late carboniferous early permian the carbon isotopic composition 13ccoal vpdb of coal samples from the taiyuan and shanxi formations of qinshui and north china bohaiwan basins ranges from 25 3 to 22 7 with an average of 23 7 the average 13ccoal value is 23 6 in the late carboniferous 23 4 in the early permian and 23 5 in the mid early permian by contrast equivalent early permian coals in the southern north china bohaiwan basin to the east were found to be significantly more negative at 25 2 likely as a function of regional aridity changes related 15n in coal seams ranges from 2 3 to 4 7 with an average of 3 7 within the thick economically important 15coal seam of the qinshui basin 15ncoal is significantly more negative than 15n in mudstone partings avg 7 1 implying that the coals underwent a stronger degree of microbial degradation during peat formation 15n of mudstone partings varies stratigraphically with significantly more positive 15n 8 1 8 3 for the lower partings and lower 15n 4 8 for the upper parting this may reflect varying degrees of microbial activity but could reflect higher thermal maturity in the upper part of the seam as indicated in the coal rank profile 13ccoal in this region was used to calculate the carbon isotopic composition of atmospheric co2 13ca calculated 13ca ranges from 6 0 to 3 4 with an average of 4 5 which is more positive than the 13ca of modern atmospheric co2 8 5 graven et al 2017 two 13ca excursions are noted a positive one magnitude 3 7 in the late carboniferous and a tentative negative excursion magnitude 6 0 in the mid early permian the positive shift coincided with a sea level transgression in the qinshui basin the rise in sea level may have led to the burial of more terrestrial plant debris that decreased photosynthesis and enriched atmospheric co2in 13c more data are needed to understand mid early permian variation in 13c as this could reflect a regional aridity or humidity effect rather than a global signal

nitrogen in rock occurrences and biogeochemical implications 1 there is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations nitrogen bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification nitrogen in rock originates as organically bound nitrogen associated with sediment or in thermal waters representing a mixture of sedimentary mantle and meteoric sources of nitrogen rock nitrogen concentrations range from trace levels 200 mg n kg 1 in granites to ecologically significant concentrations exceeding 1000 mg n kg 1 in some sedimentary and metasedimentary rocks nitrate deposits accumulated in arid and semi arid regions are also a large potential pool nitrogen in rock has a potentially significant impact on localized nitrogen cycles elevated nitrogen concentrations in water and soil have been attributed to weathering of bedrock nitrogen in some environments nitrogen released from bedrock may contribute to nitrogen saturation of terrestrial ecosystems more nitrogen available than required by biota nitrogen saturation results in leaching of nitrate to surface and groundwaters and where soils are formed from ammonium rich bedrock the oxidation of ammonium to nitrate may result in soil acidification inhibiting revegetation in certain ecosystems collectively studies presented in this article reveal that geologic nitrogen may be a large and reactive pool with potential for amplification of human impacts on nitrogen cycling in terrestrial and aquatic ecosystems

relationships between very low grade metamorphism and tectonic deformation examples from the southern central iberian zone iberian massif variscan belt abstract we have studied the syn kinematic very low grade metamorphism in a polyphase variscan deformed region using x ray diffraction techniques two phases of regional metamorphism are related to their respective episodes of penetrative deformation in the southern central iberian zone the data obtained suggest that the rocks did not reach metamorphic equilibrium but strain favoured the progress of mineral reactions in the more deformed parts the first deformation is devonian in age and consists in a heterogeneous ductile shearing coeval with large scale recumbent folding that were produced under high anchizone to epizone metamorphic conditions the heterogeneity of the shearing originated strain gradients that can be said to enhance the growth of new minerals and the illite polytype transformation in the highly strained overturned limb of the preserved pile of recumbent folds but illite crystallinity remained constant throughout the structure the second deformation is mid carboniferous in age and consists in an upright folding that took place under late diagenesis to low anchizone metamorphic conditions the distribution of mineral parageneses and illite crystallinity across one of the upright folds suggests that strain gradients favoured the metamorphic reaction progress from the hinge low strain towards the limbs high strain other characteristics of the region such as a metamorphic gap associated with an unconformity at the base of the lower carboniferous rocks or cryptic contacts aureoles surrounding volcanic intercalations and a large granitic batholith are also studied

hydrothermal synthesis of ammonium illite synthetic gel and glass of illitic composition natural kaolinite and mixed layer illitesmectite were used as starting materials for hydrothermal synthesis of ammonium illite ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300 8c the onset of crystallization began within 3 h and well crystallized ammonium illite appeared at 24 h increasing reaction time up to four weeks led to many illite layers per crystal in the presence of equivalent proportions of potassium and ammonium the gel was transformed to illite with equimolar contents of k and nh4 in contrast synthesis using glass under the same conditions resulted in a mixture of mixed layer ammonium illite smectite with large expandability and discrete illite hydrothermal treatments of the fine fractions of natural kaolinite and illite smectite produced ammonium illite from kaolinite but the illite smectite remained unchanged

drought reconstructions for the continental united states abstract the development of a 2 lat 3 long grid of summer drought reconstructions for the continental united states estimated from a dense network of annual tree ring chronologies is described the drought metric used is the palmer drought severity index pdsi the number of grid points is 154 and the reconstructions cover the common period 1700 1978 in producing this grid an automated gridpoint regression method called point by point regression was developed and tested in so doing a near optimal global solution was found for its implementation the reconstructions have been thoroughly tested for validity using pdsi data not used in regression modeling in general most of the gridpoint estimates of drought pass the verification tests used in addition the spatial features of drought in the united states have been faithfully recorded in the reconstructions even though the method of reconstruction is not explicitly spatial in its design the drought reconstructions show that the 1930s dust bow

ammonium contents of biotites from precambrian rocks in finland the significance of nh4 as a possible chemical fossil abstract the ammonium contents of biotites in precambrian rocks from finland have been determined to examine the possibility that ammonium in biotites represents a chemical fossil if biologic activity existed in precambrian sedimentary environments biotites formed from the sediments should contain distinctly larger quantities of nh 4 than biotites from igneous rocks biotites from svecokarelidic metasediments which were originally products of sedimentation about 2400 1900 ma ago have high nh 4 contents hundreds of ppm while biotites from svecokarelidic plutonic rocks of 1800 1900 ma old and postsvecokarelian rapakivi granites of 1650 1700 ma old have low nh 4 contents tens of ppm the results may indicate that biologic activity was plentiful during sedimentation of the svecokarelian strata this agrees with evidence for ancient life found in dolomites and greywacke slates of the svecokarelides biotites from presvecokarelidic schists of more than 2600 2800 ma old have only tens of ppm of nh 4 this value is at the same level as those of biotites from the rapakivi granites and the svecokarelidic plutonic rocks considering the rarity of fossils in presvecokarelidic rocks the low nh 4 content of biotite from a presvecokarelidic pelitic schist may indicate less biologic activity during the sedimentation of the original sediments these data emphasize that ammonium in biotites of precambrian metasediments may be a useful chemical fossil for identifying the geologic sites of ancient life

distribution and origin of minerals in high rank coals of the south walker creek area bowen basin australia the coals of the south walker creek area in the northern bowen basin with a vitrinite reflectance rvmax of 1 7 to 1 95 are among the highest rank coals currently mined in australia x ray diffraction studies have identified an unusual mineral variation through the vertical sequence with kaolinite rich assemblages typical of other australian coals at the top and bottom of the seam section and an illite chlorite assemblage resembling a metamorphic association in the middle calcite and ankerite are also abundant in parts of the vertical sequence diaspore is abundant in the middle section of the seam in some areas and paragonite dickite or nacrite occurs in some locations as well the distribution of the non carbonate mineral assemblages cross cuts the seam stratigraphy and appears to be primarily controlled by faults and other structural features integration of the mineral distribution with optical and electron microscope data on the coal and non coal bands chemical data from coal ash analysis and information from x ray micro tomography suggests that the illite chlorite and diaspore bearing assemblages resulted from hydrothermal effects associated with fluid migration through the middle part of the coal seam this is further confirmed by the development of metamorphic textures in a tonstein band also altered to illite and chlorite in the illite rich part of the seam section in contrast to a tonstein with more normal sedimentary textures and a kaolinite composition in the kaolinite rich upper part of the seam detailed studies of cleat mineralisation suggest that fluids rich in ca mg and al were introduced relatively early in the seam s post depositional history associated with heat flow sufficient to alter the minerals in the coal and tonstein in the affected part of the seam section the relatively uniform vitrinite reflectance profile observed through the seam section may indicate that the coal was already of high rank before the fluids were introduced or that any localised heat effects on the organic matter associated with the changes in clay mineralogy were overprinted by subsequent wider ranging rank advance processes

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

variations in coal maceral chemistry with rank advance in the german creek and moranbah coal measures of the bowen basin australia using electron microprobe techniques abstract variations in the elemental composition of individual macerals in seams from the permian german creek and moranbah coal measures in the bowen basin of queensland have been studied over a wide range of coal ranks using light element electron microprobe techniques to establish the coalification tracks of key macerals in a single coal bearing interval from subbituminous through bituminous coal to anthracite vitrinite reflectance rv max in the seams studied increases from 0 39 in the western part of the basin to over 3 5 in the east apparently due to increases in burial depth the study extends significantly the rank range covered by previous work on elemental analysis of individual macerals in the gunnedah basin and provides a more useful basis than whole coal analysis to evaluate the performance of coals in different utilisation processes the microprobe results show that the carbon content of the telocollinite increases dramatically from 66 to 90 as the vitrinite reflectance of the coals rv max increases from 0 39 to around 1 75 but increases only slightly from 90 to 91 as rv max increases from 1 75 to 3 52 oxygen decreases from around 26 to approximately 5 as rv max increases from 0 39 to around 1 75 and then decreases only very slightly into the anthracite range the nitrogen content of the telocollinite in these coals also appears to decrease slightly with rank advance and appears moreover to display a relatively abrupt drop at around 2 rv max this may be associated with the development of ammonium illite in the mineral matter organic sulphur in the telocollinite on the other hand seems to remain essentially constant with rank advance at least in this particular succession in contrast to vitrinite fusinite and inertodetrinite have significantly higher but somewhat more constant carbon contents varying only from around 81 to 93 c over the rank range studied oxygen in these macerals decreases from around 12 to a little over 2 with the same degree of rank advance sulphur and possibly nitrogen also appear to be significantly lower in fusinite and inertodetrinite than in the vitrinite of the same coal samples semifusinite is somewhat more variable in composition with characteristics intermediate between those of the fusinite inertodetrinite and those of the vitrinite in the same coal over the rank range studied

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

nitrogen in future biosphere studies this article suggests a theme for future nitrogen studies involving the functioning and evolution of the biosphere together with certain aspects of human biology it is hoped that this theme could be developed into a multi authored book at some point in the future although numerous new case studies may be required the biosphere can be considered to be a single interactive system comprised of numerous component parts including the atmosphere rain rivers lakes oceans continental ecosystems marine ecosystems soils and sediments in order to study the internal complexity of each of the components and the relationships that exist between them one can choose a common theme the author believes that nitrogen is a good prospect because of its ubiquitous nature and complex chemistry the burial of sedimentary volatiles in the continental crust has contributed to the long term chemical evolution of the exterior environments of the earth the most marked effects notably the accumulation of atmospheric oxygen have been due to the burial of reduced carbon an understanding of the passage of sedimentary volatiles through the crust will provide important constraints on the evolution of the biosphere and may lead to a more meaningful comparative planetology carbon is difficult to trace through crustal processes because its high temperature form graphite is incompatible with the crystal structures of silicate minerals however the high temperature form of sedimentary nitrogen ammonium readily enters into potassic minerals and it can be easily traced through crustal processes herein the fate of sedimentary nitrogen is traced from wet sediments through metamorphic rocks into granites and other crustal melts without the trapping of nitrogen in the crust and the liberation of oxygen that is a consequence of biological nitrogen fixation the n2 o2 of the atmosphere may have been about 82 9 to 16 3 and the total atmospheric pressure about 1 2 atm most of the changes in the oxygen content is due to dilution by nitrogen with only about 5 of the present atmospheric oxygen being a consequence of nitrogen fixation the ancient continental surfaces would have been volcanic deserts containing little 1 ppm or no nitrogen today nitrogen rich soils support continental ecosystems one can use nitrogen as a window to speculate on the colonisation of the continents by land plants herein nitrogen fixation by legumes is considered in detail and by drawing analogies with the present day the author speculates on the colonisation of the continents by land plants having speculated on the co evolution of the atmosphere soils and continental ecosystems one can place a human being in the centre of a tropical forest and begin to examine how they relate to the modern biosphere the chosen example is the metabolism of plant protein and the roles of glutamate dehydrogenase gdh vitamin b2 and flavin mononucleotide fmn the realisation of this theme would imply numerous new case studies notably those concerning the continental crust where nitrogen studies were linked to mineralogy petrology and other geochemical tracers including sr o al and k and where the short range order of 15n were taken into consideration

history of applied coal petrology in the united states iv reflections on the centennial of the introduction of coal petrology to north america abstract reinhardt thiessen introduced a thin section based botanically oriented method of coal petrology to north america in 1920 the nomenclature derived from this system although eventually reconciled with and largely superseded by the european reflected light techniques and nomenclature persisted for decades after thiessen s death in 1938 the research by thiessen and his colleagues at the u s bureau of mines was the foundation of applied coal petrology in the united states with research on the preparation coking and hydrogenation properties of coals thiessen s botanical training enabled him to recognize distinct spores in coals although he did not macerate the samples and he did not provide genus and species names the demonstration that he could use spores to correlate coals through the northern appalachian coal basin provided a foundation for regional stratigraphic palynology homer turner an american geologist and fuel scientist was a pioneer in the petrographic study of anthracite using a method of etching polished blocks of anthracite he developed a parallel approach to reinhardt thiessen s studies of thin sections of bituminous and lower rank coals describing well preserved botanical structures this in turn supported the view that anthracite just had a higher degree of metamorphism than bituminous coals opposed to the older view that anthracite had a different botanical origin in a joint study with the u s bureau of mines turner produced a map of equal volatile matter contours isovol across the pennsylvania anthracite fields he was also a collaborator in a study on the x ray diffraction structure of anthracite presaging better known studies by rosalind franklin and others

petrology and geochemistry of diagenetically altered tuffaceous rocks from the middle triassic of central spain abstract petrographical and geochemical analysis of altered tuffaceous rocks of the middle triassic from the iberian range in central spain shows that pedogenic processes and subsequent diagenesis have strongly modified the original mineralogy and textures these rocks are related to a magmatic episode that occurred at the buntsandstein muschelkalk unconformity in this region during the evolution of the iberian trough the tuffaceous rocks accumulated in saline ponds in an open and terminal flood plain setting their alteration is typified by neoformation of k feldspar and illite precipitation of chert and carbonate cements and replacements were also important processes resulting in intercalated chert beds and nodules much of the silica appears to be derived from extensive devitrification and weathering of glassy volcanic ash x ray diffraction analysis microscopic observations and edx microanalysis reveal that the chert consists of various types of chalcedony tridymite micro and megaquartz illite k feldspar and small amounts of albite in some of the nodules dolomite ankerite is also common enclosing anhydrite and barite relicts which are partially silicified different levels of ammonium enrichment have been found in each petrofacies type tuffs and tuffaceous rocks contain from 27 to 326 ppm mean 139 of nh4 underlying arkosic sandstones with authigenic k feldspar contain nh4 ranging from 48 ppm to 191 ppm mean 124 the nh4 was probably derived from decay of organic matter in the evaporitic environment of deposition and its incorporation into feldspar and illite as they formed from unstable volcanic glass sanidine plagioclase and vitric volcanic fragments this transformation could have occurred via the intermediate phases of smectite and zeolites the tuffaceous rocks also have a high content of b ranging from 61 ppm to 170 ppm mean 101 however high levels of b are not positively correlated with high levels of nh4 in the samples both b and nh4 can be contained in either k feldspar or illite but it is not possible to know how much is present in each mineral without separating the minerals comparison of spidergrams of the tuffaceous rocks with those in the underlying arkosic sandstones indicates similar patterns with positive anomalies in la sm and y and negative in nb p ti and yb although the tuffaceous rocks are slightly richer in total ree these data suggest that the distribution of ree must also be controlled by weathering and diagenetic reactions and cannot be used for discrimination between volcanic and nonvolcanic sandstones

clay mineral authigenesis in coal and shale from the anthracite region pennsylvania textural chemical and mineralogical analyses of authigenic clays in anthracite rank coal and associated shale from eastern pennsylvania have allowed a better understanding of the parameters controlling diagenesis and perhaps coalification in this region minerals in anthracite occur in distinct assemblages associated with the following microenvironments coal matrix two orthogonal joint sets termed systematic and nonsystematic cleat and a third joint set mineralogical differences among microenvironments allow inferences about clay mineral origins and the parameters that controlled mineral authigenesis kaolinite occurs in the shale and all microenvironments within the coal seam authigenic minerals that replaced preexisting kaolinite during the latest stage ofcoalification anthracitization at t 200 c include nhu rich illite pyrophyllite and the following minerals which are primarily restricted to the systematic cleat set tosudite rl ordered dioctahedral mixed layer chlorite smectite sudoite di trioctahedral chlorite and rectorite rlordered mixedjayer paragonite smectite alteration of smectite to illite may be responsible for formation of authigenic illite and na bearing illite which are present only in the shale and coal matrix and fe al rich chlorite and quartz in the third joint set the chemical components for authigenesis appear to have multiple sources ai and si from preexisting kaolinite and quartz n from local organic matter mg and na for tosudite sudoite and rectorite largely from metasomatic hydrothermal fluids fe and mg for fe al rich chlorite from smectite illitization minerals in the shale the coal matrix and the nonsystematic cleat set are interpreted to represent authigenesis in a low permeability environment closed system alteration however the assemblage sudoite tosudite rectorite in the systematic cleat set is interpreted to be the result ofone or two stages ofhydrothermal alteration open system alteration we suggest hat differences in minerals between the two nearly perpendicular cleat sets are the result of permeability differences which were maintained by an anisotropic lateral stress field created by plate convergence during the alleghanian orogeny hydrothermal alteration may be related to large scale basinal flow induced by alleghanianage uplift such migrating fluids could also have transported heat from depth and thereby significantly increased the rate and rank ofcoalification in this region

the measurement of δ15n in crustal rocks by static vacuum mass spectrometry application to the origin of the ammonium in the cornubian batholith southwest england the release of ammoniacal nitrogen from muscovite biotite orthoclase microcline and a whole rock granite by vacuum pyrolysis has been investigated under the heating regimes employed it was found that micas lose most of their nitrogen below the temperature at which the powders begin to sinter ca 1100 c the peak release of n occurring in either the 900 c or 1000 c heating step it is possible that the loss of ammonium is linked to the loss of h2o and perhaps f for the feldspars there was insignificant release of n below the melting point of the minerals about 1150 c suggesting that diffusion of ammonium or ammonia is the principal control for both micas and feldspars there was significant kinetic fractionation of the nitrogen isotopes during stepped heating from these results a technique has been devised for the routine determination of 15n and ammonium concentration in whole rock granites by static vacuum mass spectrometry the ammonium concentrations and 15n values have been determined in whole rock samples from the cornubian batholith southwest england the ammonium concentrations were in the range 8 to 187 ppm and the 15n values were in the range 5 1 to 10 2 most of the granite samples had 15n values between 8 4 and 10 2 and are within the range that have been obtained from amphibolite facies metasediments these granites are also typified by high 87sr86srinit 0 7130 to 0 7166 and high normative corundum 2 31 to 2 55 taken together the data suggest that the ammonium present within these granites is of biological origin and that it was incorporated via the anatexis of metasediments which originally contained organic material the samples were collected over a distance of 120 km and the limited range in 15n suggests either 1 1 the 15n values within the metasedimentary protolith were rather homogeneous or 2 2 the nitrogen isotopes were homogenised during the incorporation of ammonium into the granite magmas two of the granites had lower 15n values of 5 1 and 7 0 these granites also have lower ammonium concentrations 8 and 15 ppm lower 87sr86srinit 0 7094 0 7095 and lower normative corundum 1 44 and 1 63 the preferred explanation is that they were derived from or have had a contribution from a second crustal source containing sedimentary or metasedimentary material with a lower proportion of pelitic to other constituents

partitioning of mineralogical and inorganic geochemical components of coals from santa catarina brazil by industrial beneficiation processes abstract comparative studies of the mineral matter and trace elements in 12 pairs of run of mine rom and clean coal products from beneficiation plants in santa catarina southern brazil have been carried out using low temperature oxygen plasma ashing x ray diffraction and chemical analysis techniques with the aim of evaluating the effect of coal preparation on the mineralogy and chemical composition of the final coal products the results show that substantial reductions in mineral matter and ash percentages are associated with beneficiation of coals mined from the different deposits these reductions are accompanied by changes in the percentages of fe2o3 in the respective coal ashes due to the reduction in the proportion of pyrite in the mineral matter and also by a reduction in the percentage of na2o possibly due to ion exchange within the clay minerals the relative proportions of quartz clay minerals and minor phases such as calcite and feldspar mainly albite within the mineral matter are not however significantly changed by the beneficiation processes the concentrations of most trace elements in the beneficiation products are similar to the respective concentrations in the relevant rom materials or are reduced to an extent similar to that of the total mineral matter percentage for the respective coal samples this suggests an association mainly with the clay rich mineral matter the concentrations of as and pb however are reduced to a greater extent for most samples by the beneficiation processes consistent with a pyrite association concentrations of ge u and zr are higher in many of the clean coals than in the respective run of mine materials suggesting the possibility of preferential association at least for some deposits with the organic rich fractions of the coals concerned

clays and other minerals in coal seams of the moura baralaba area bowen basin australia abstract the clays and other minerals in a succession of late permian coals of high volatile bituminous to semi anthracite rank have been identified using low temperature oxygen plasma ashing and x ray diffraction and evaluated to identify the relative roles in mineral matter formation of detrital input early diagenesis in the peat swamp and late diagenesis associated with rank advance although well ordered kaolinite of probable early diagenetic origin is abundant throughout the succession the uppermost and lowermost seams of the sequence regardless of rank contain relatively abundant illite and or interstratified illite smectite along with a small but significant proportion of chlorite these clays are thought to be essentially of detrital origin washed or blown into the peat deposit in relative abundance during the establishment and subsequent overwhelming of an extensive and long lived swampy environment quartz is also abundant in the lower seams of the sequence especially close to the regional sediment source area illite is unusually abundant in the topmost seam in both high and low rank parts of the succession and thus appears to represent detrital input from a particular source material although significant changes are reported in the clays of the associated strata due to rank advance the principal effect of rank advance on the minerals in the coal itself appears to be the development of an ammonium illite and possibly some additional fine grained chlorite in the semi anthracite material isolation within the organic matter of the coal is thought to have inhibited access for ions such as k which might otherwise have become involved in metamorphic reactions and given rise to mineralogical changes commonly found in non coal sedimentary successions

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

mineralization of organogenic ammonium in the monterey formation santa maria and san joaquin basins california usa abstract inorganic fixed ammonium nh4 contents as high as 0 28 wt were measured in organicrich quartz grade siliceous rocks of the miocene monterey formation from the santa maria and san joaquin basins california the greatest amount of fixed nh4 was found in rocks associated with hydrocarbons in the point arguello and lost hills oil fields where the nh 4 nh 4 k molar ratio of bulk samples ranges from 0 17 0 35 the formation of nh4 illite is suggested by the parallel increase in the percent of illite in the mixed layered illite smectite i s and in the nh 4 nh 4 k molar ratio of the clay sized fraction with increasing burial depth mineralization of nh4 appears to be promoted by the coincident timing of the smectite to illite clay mineral transformation and the release of nh4 during catagenesis nh4 feldspar may form at shallow burial depths in rocks from the point arguello field that contain a greater amount of detrital k feldspar and in which the i s contains only 10 20 illite quartzgrade siliceous monterey rocks from coastal outcrops in the lions head area lack significant amounts of hydrocarbons and have nh 4 nh 4 k molar ratios of 0 14 0 21 rocks from the lions head area show a strong positive correlation between diagenetic illite and fixed nh4 contents with nh4 constituting 18 21 mol of the fixed interlayer cations in the i s low grade opal a and opal ct siliceous miocene rocks from coastal outcrops in the pt pedemales area have low fixed nh4 contents 0 01 wt because these rocks contain minor amounts of diagenetic k bearing minerals i s contains 10 illite and they lack significant amounts of generated or migrated hydrocarbons the increase in the organic c n ratio with burial depth most likely reflects the preferential release of n compared to c and suggests that nh4 release is greatest during shallow burial bacterial degradation and deep burial catagenesis oil generation the results of this study support the suggestion of williams et al 1989 that high fixed nh4 contents may provide a long term geologic record of low temperature

case study of igneous intrusion effects on coal nitrogen functionalities this study presents the results of the nitrogen xps analysis performed on a set of four bukit asam indonesia low rank coals and on a related natural pyrolysis product formed after an igneous intrusion low rank coal nitrogen xps sub peak is dominantly pyrrolic with subordinate quaternary and pyridinic dike intrusions are responsible for transformation of these nitrogen forms nitrogen to graphitic quaternary nitrogen the transformation of nitrogen is similar to that exhibited by laboratory prepared pyrolysis products of other coals

the elemental and isotopic composition of sulfur and nitrogen in chinese coals abstract coal combustion is an important atmospheric pollution source in most chinese cities so systematic studies on sulfur and nitrogen in chinese coals are needed the sulfur contents in chinese coals average 0 9 1 0 indicating that most chinese coals are low in sulfur a nearly constant mean 34 s value is observed in low sulfur ts 1 t 3 and j 3 high sulfur chinese coals os 0 8 often found at late carboniferous c 3 and late permian p 2 in southern china had two main sulfur sources original plant sulfur and secondary sulfur the wide variety of 34 s values of chinese coals 15 to 50 is a result of a complex sulfur origin the 15 n values of chinese coals ranged from 6 to 4 showing a lack of correlation with coal ages whereas nitrogen contents are higher in paleozoic coals than in mesozoic coals this may be related to their original precursor plant species high nitrogen pteridophytes for the paleozoic coals and low nitrogen gymnosperms for the mesozoic coals different to 34 s values chinese coals showed higher 15 n values in marine environments than in freshwater environments

enrichment of u re v cr se and rare earth elements in the late permian coals of the moxinpo coalfield chongqing china genetic implications from geochemical and mineralogical data abstract rare metals in coal deposits have attracted much attention in recent years because of their potential economic significance this paper reports the abundance and enrichment origin of rare metals in the late permian coals k1 and k2 coals of the moxinpo coalfield chongqing southwestern china the k1 coal is characterized by highly elevated concentrations of u re v cr se and nb ta zr hf ree assemblages the latter assemblage is also enriched in the k2 coal the high temperature ash 815 c of the k1 coal is enriched in v cr se re u and ree the ash of the k2 coal and also the floor strata of each seam are enriched in ree potentially making all of the units economically viable sources for these elements the minerals in the k1 coal are mainly represented by kaolinite illite and mixed layer illite smectite and pyrite while the minerals in the k2 coal consist mainly of kaolinite and tobelite nh 4 k al 2 alsi 3 o 10 oh 2 authigenic roscoelite k v 3 al 2 alsi 3 o 10 oh 2 is commonly observed in the k1 coal under the sem and was probably formed by interaction of kaolinite with v derived from permeating u re v cr se rich solutions during early diagenesis the tobelite enriched in the k2 coal was formed by reaction between kaolinite already present in the coal and nh 4 derived from decomposition of the organic matter during hydrothermal alteration at a relatively high temperature the mafic tuffs directly underlying the k1 coal and containing limestone residual breccias not only served as the substrate for coal accumulation but also as the source of sediment from the uplifted areas around the coal basin the latter is indicated by low al 2 o 3 tio 2 ratios from 10 09 to 14 24 positive eu anomalies enrichment of medium rare earths relative to upper continental crust and detrital calcite of terrigenous origin the highly elevated concentrations of u re v cr se assemblages in the coal were derived from exfiltrational hydrothermal solutions and were then deposited in a euxinic environment the terrigenous materials in the k2 coal however were derived from felsic intermediate rocks at the top of the kangdian upland although the elevated concentrations of nb ta zr hf ree assemblages are attributed to the input of hydrothermal solutions

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

ammonium geochemistry in mineral exploration a comparison of results from the american cordilleras and the southwest pacific abstract ammonium concentrations in the host rocks to circum pacific epithermal precious metal and exhalative base metal deposits vary from 0 to 25 000 ppm high ammonium concentrations in mineralizing fluids are probably derived from the breakdown of organic matter in sediments or sedimentary rocks within the hydrothermal system shales are particularly good ammonium source rocks ammonium substitutes for k and other alkali elements in crystal lattices host rocks with k bearing minerals therefore have the highest potential for the development of ammonium haloes both surface and subsurface rocks can contain high concentrations of ammonium and substantial haloes have been found associated with precious metal veins particularly in the hanging wall such haloes are well developed at mines in mexico bolivia and peru and ammonium geochemistry thus provides a potentially useful exploration tool especially for vein type epithermal precious metal deposits

determination of the content and distribution of fixed ammonium in illite smectite by x ray diffraction application to north sea illite smectite a new x ray diffraction method for the determination of the amount and distribution of fixed nht in illite smectite has been developed illite smectite was saturated with k and heated at iso c the 002 and 005 reflections were recorded with steps of 0 01028 and the experimental d values and the values for full width at half height fwhh were determined using a peak profile fitting procedure peak profiles were calculated with the newmod program for illite structures having different amounts of nh and different patterns for the distribution of nh in interlayers for upper jurassic illite smectite from north sea oil source rocks the amount and the distribution of nh in illite interlayers were determined by comparing the experimental values for doo5 and fwhh with the values calculated for the selected illite structures the amounts of nh determined in this manner correlate well with the amounts determined by an isotopic dilution method the results demonstrate that these illite smectite samples have k end member illite and nh4 endmember illite tobelite layers and that the illite layers formed during diagenesis and oil generation actually are tobelite layers

interpretation of the nitrogen isotopic composition of precambrian sedimentary rocks assumptions and perspectives nitrogen isotope compositions in sedimentary rocks d 15 n sed are routinely used for reconstructing cenozoic n biogeochemical cycling and are also being increasingly applied to understanding the evolution of ancient environments here we review the existing knowledge and rationale behind the use of d 15 n sed as a proxy for the precambrian n biogeochemical cycle with the aims of i identifying the major uncertainties that affect analyses and interpretation of nitrogen isotopes in ancient sedimentary rocks ii developing a framework for interpreting the precambrian d 15 n sed record iii testing this framework against a database of precambrian d 15 n sed values compiled from the literature and iv identifying avenues of focused research that should increase confidence in interpreting precambrian d 15 n sed data this review highlights the intrinsic complexity of the d 15 n sed proxy and the significant effort that remains to realize its potential specifically it is crucial to gain a better understanding of how and when diagenesis and metamorphism affect the d 15 n of bulk and kerogen bound nitrogen ultimately more data are required to apply statistics to interpreting d 15 n sed variability within given geological time intervals finally numerical modeling of the d 15 n sed variability expected in different environments under varying redox scenarios is necessary to establish a predictive template for interpreting the ancient nitrogen isotope record in spite of the challenges facing the application of this proxy to the precambrian the existing d 15 n sed record shows several features possibly related to the stepwise oxygenation of the surface environment underlining the potential for nitrogen isotopes to reveal clues about the evolution of early earth

inorganic nitrogen in anthracite from eastern pennsylvania usa abstract up to 20 of the total nitrogen content of anthracite rank coal from eastern pennsylvania occurs in authigenic nh 4 rich illite this enrichment is due to the concurrence of two independent reactions in the coal and surrounding organic rich shale during late stage organic maturation and diagenesis t 200 c 1 the release of n from organic matter by devolatilization reactions and 2 the formation of illite from kaolinite our estimates of inorganically bound n are conservative because minerals in fractures which can be volumetrically important were removed prior to analysis inorganic n estimates using x ray diffraction analysis are similar to those obtained by elemental analysis of combusted material the occurrence of inorganically bound n in organic rich rocks has important implications for geochemical characterizations of high rank coal n content and isotopic composition and laboratory investigations of the kinetics of n loss from organic material during thermal maturation in addition because nh 4 rich illite authigenesis is temporally linked to coalification the radiometric age of this mineral can theoretically be used to determine the absolute age of coalification in this region for detailed characterization of high rank coal we recommend that mineral matter be isolated by low temperature ashing and analyzed by x ray diffraction or c h n elemental analysis for inorganically bound n

twentieth century trends in tree ring stable isotopes δ13c and δ18o of larix sibirica under dry conditions in the forest steppe in siberia 1 tree ring width density and ratio of stable isotopes 13c 12c and 18o 16o in wood and cellulose were determined for larch larix sibirica ledeb growing under water deficit conditions in the forest steppe zone in central siberia 54 24 n 89 57 e for the period 1850 2005 dendroclimatic analysis of the chronologies indicated precipitation to be the most important factor determining indicated parameters precipitation of june is significantly correlated with tree ring width and maximum density r 0 36 and 0 43 p 0 05 respectively relations of 13c and 18o to precipitation are similar but the most important month is july r 0 47 p 0 05 for 13c r 0 29 p 0 05 for 18o further 18o is positively related to the mean temperatures of july r 0 30 p 0 05 carbon and oxygen isotope ratios in wood and cellulose showed strong negative trends for the last 100 years the reason for this decrease could be the observed shift of the beginning of the vegetation period to earlier dates up to 1 week in spring and the increased use of precipitation water stored in the soil from october of the previous year although other explanations cannot be excluded in particular the physiological effect of increasing atmospheric co2 also responsible for lower 13c values thus an earlier start of the vegetation period could lead to tree ring formation during a period with higher water availability resulting in stronger isotopic fractionation and 13c depletion also reflected in a higher earlywood to latewood ratio at the same time highly 18o depleted water from october precipitation of the previous year is absorbed the incorporation of this isotopically lighter water during photosynthesis is reflected in the wood and cellulose of tree rings

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

isotopic variations of the fixed nitrogen in metamorphic rocks the content and isotopic composition of fixed nitrogen nh 4 n in metasedimentary rocks phyllites mica schists and gneisses from prograde metamorphic zones in the erzgebirge saxon ore mountains g d r were measured and show that the nitrogen content decreases and 15n increases with increasing metamorphic grade the geochemical and isotopic behaviour of nitrogen during contact metamorphism was investigated in a mica schist profile through the contact aureole of a granitic pluton the nitrogen concentrations of the wall rocks decrease towards the contact whereas the 15n values become higher various model experiments were carried out in the laboratory to explain the changes observed in the rock samples the nitrogen isotope fractionation factor was determined for the isotopic exchange in the system ammonium sulphate ammonia at 250 c 1 0143 0 0012 and 350 c 1 0128 0 0006 in accordance with the model experiments the conclusion seems warranted that the change in nitrogen content and its isotopic composition in rocks during metamorphic processes depend mainly on the metamorphic temperature

development of large north facing folds and their relation to crustal extension in the alboran domain alpujarras region betic cordilleras spain detailed research in the eastern part of the alpujarras region betic cordilleras has revealed the existence of large recumbent fold structures involving lithological sequences previously considered to belong to different tectonic units we have reconstructed a large complex fold structure which can be followed axially for over 50 km based on a careful revision of the boundaries between lithological formations a structural analysis of the carbonate and metapelite sequences and the use of mineralogical techniques such as measurements of d001 basal spacing of phengite paragonite and chlorite determinations of the illite crystallinity index ic and b0 parameters of mica and chlorite structural field data described in this paper include gently dipping axial plane cleavage surfaces common occurrence of gently dipping boudinage and pinch and swell structures and associated sub orthogonal stretching lineation similarity in orientation of this stretching lineation with the slip direction of the low angle normal faults and close association between north facing recumbent folds and top to the north low angle normal faults the slip direction of the faults being broadly perpendicular to the fold axes these features clearly indicate that extensional processes played a decisive role in the generation of the alpujarras large recumbent folds the development of these recumbent folds probably occurred during the early to middle miocene extensional tectonics that affected the betic cordilleras the formation of large scale folds in association with normal faulting is consistent with the p t paths and geochronological data established for the alpujarride region

mechanisms of coal metamorphism case studies from paleozoic coalfields controls on coal metamorphism can be complex in this paper we examine four paleozoic coalfields the western kentucky portion of the illinois basin the pennsylvania anthracite fields the south wales coalfield and the bowen basin an increase in temperature with depth of burial is certainly a factor in coal metamorphism in many coalfields however including the coalfields reviewed here it has become apparent that such a simple mechanism does not explain the coal rank patterns observed the flow of hydrothermal fluids through the coals has been proposed as a cause of coal metamorphism evidence includes inverted rank gradients elevated cfl as an indicator of brine fluids isotopic evidence for hydrothermal fluids and vein and cleat mineral assemblages in any case multiple hypotheses must often be evaluated in the examination of any coalfield since the simple paradigm of coal rank increases with a simple increase in temperature with increasing depth does not fit the evidence observed in many cases

mineral matter and trace elements in coals of the gunnedah basin new south wales australia abstract the concentrations of major and trace inorganic elements in a succession of permian coals from the gunnedah basin new south wales have been determined by x ray fluorescence techniques applied to both whole coal and high temperature ash samples the results have been evaluated in the light of quantitative data on the minerals in the same coals determined from x ray diffraction study of whole coal samples using a rietveld based interpretation program siroquant to determine relationships of the trace elements in the coals to the mineral species present comparison of the chemical composition of the coal ash interpreted from the quantitative mineralogical study to the actual ash composition determined by xrf analysis shows a high degree of consistency confirming the validity of the xrd interpretations for the gunnedah basin materials quartz illite and other minerals of detrital origin dominate the coals in the upper part of the sequence whereas authigenic kaolinite is abundant in coals from the lower part of the permian succession these minerals are all reduced in abundance however and pyrite is a dominant constituent in coals formed under marine influence at several stratigraphic levels calcite and dolomite occur as cleat and fracture infillings mostly in seams near the top and bottom of the sequence the potassium bearing minerals in the detrital fraction are associated with significant concentrations of rubidium and the authigenic kaolinite with relatively high proportions of titanium zirconium is also abundant with associated p and hf in the gunnedah basin coal seams relationships exhibited by ti zr nd and y are consistent with derivation of the original sediment admixed with the seams from an acid volcanic source pyrite in the coals is associated with high concentrations of arsenic and minor proportions of thallium no other element commonly associated with sulphides in coals however appears to occur in significant proportions with the pyrite in the sample suite small concentrations of cl present in the coal are inversely related to the pyrite content and appear to represent ion exchange components associated with the organic matter strontium and barium are strongly associated with the cleat filling carbonate minerals ge and ga appear to be related to each other and to the coal s organic matter cr and v are also related to each other as are ce la nd and pr but none of these show any relationship to the organic matter or a particular mineral component

diagenesis of ammonium during hydrocarbon maturation and migration wilcox group louisiana u s a abstract as organic matter matures n is released in the reduced form as nh4 and substitutes for k in clay minerals as oil forms an abundance of n is generated coincident with the formation of authigenic illite this study suggests that nh4 released from organic matter during maturation migrates through sandstones together with the pore fluids and volatile phases generated from the migrating crude oil this causes anomalously high nh4 substitution in authigenic illites fixed nh4 concentrations in illite are a product of both hydrocarbon maturation and migration concentrations of fixed nh4 from organic rich mudstones in two wilcox group oil fields show a general increase with depth coincident with increasing organic maturation reservoir sandstones containing crude oils have fixed nh4 concentrations as much as two times those of the mudstones when values are normalized to the quantity of clay minerals fixed nh4 concentrations in the gaseous portion of the reservoir are three times as high two out of five sandstones from a dry hole adjacent to a producing oil field contain anomalously high 2 above mean concentrations of fixed nh4 with respect to total organic centent this together with a high production index and hydrogen index in those units suggests that migrating hydrocarbons may have influenced the fixed nh4 concentrations

isotope study on organic nitrogen of westphalian anthracites from the western middle field of pennsylvania u s a and from the bramsche massif germany abstract the objective of this study was to examine an aspect of the thermal cycling of organic nitrogen in sediments and metasediments the cycling of organic nitrogen is important because sedimentary organic matter is a shuttle of nitrogen from the atmosphere to the lower crust and thermal decomposition of organic matter is a critical step in the recycling of nitrogen between the different nitrogen pools abundance and isotopic composition of organic nitrogen were determined in the particular case of two low sulfur westphalian anthracites series from pennsylvania and bramsche massif they represent good examples of euramerica coals spanning the whole range of anthractization in single fields gold cell experimental simulation of the denitrogenation process was conducted at moderate pressure to show that both suites make ideal metamorphic profiles without any shift due to change of facies or to hydrothermal disturbance during anthracitization organic nitrogen content decreases rapidly while organic nitrogen isotopic composition does not change with rank increase the preservation of the isotopic signature implies that organic nitrogen isotopes could be used as indicators for the paleoecological and paleodepositional history reconstruction of the basins the striking contrast between the rapid and sharp decrease of nitrogen organic content and the invariance of its isotopic composition during the whole anthracitization suggests that ammonia is an important product of the denitrogenation process

the partitioning behaviour of boron from tourmaline during ashing of coal abstract boron is an environmentally sensitive element that may be present in high concentrations in some coals three modes of occurrence for boron in coal are commonly recognised namely bound to the organic fraction locked into clay minerals mainly illite and bound within the crystal lattice of tourmaline the organically bound mode is generally considered to be the most likely following combustion in a pulverised fuel utility boron is generally enriched in the fine fly ash waste but in some cases it may also escape with the flue gas suggesting variable partitioning behaviour there is concern that boron may be leached from fly ash disposal impounds at concentrations toxic to higher land plants a coal sample from the d seam of the strongman no 2 mine west coast south island new zealand has been used to test the hypothesis that boron present in tourmaline is less volatile in coal combustion implying that mode of occurrence is a key control on the partitioning behaviour of this element six sample subsets were doped with increasing amounts of ground tourmaline one subsample from each set was analysed by prompt gamma inaa to determine the concentration of boron in the coal two subsamples were ashed at 1000 c one ash sample from each set was analysed for boron while the other ash sample was leached according to australian standards it was found that the relationship between boron in the doped coal and boron in the ash is approximately linear with some losses noted during ashing indicating boron present in tourmaline was substantially retained in the ash furthermore no relationship was found between the boron content of the ash and boron leached from the ash samples by reagent water the results suggest boron present in coal as tourmaline is retained in the ash and is unavailable to the environment following fly ash disposal

triassic temnospondyls of the pranhita godavari basin india abstract the pranhita godavari p g basin of central india has yielded early middle and late triassic temnospondyl families bracyops laticeps the type for the family brachyopidae was first described from the lower triassic mangli beds of the northernmost extension of the p g basin in the northern and central parts of the p g basin itself the middle triassic yerrapalli formation has stanocephalosaurus rajareddyi a paracyclotosaurid and the upper triassic maleri formation has buettneria maleriensis a metoposaurid and two other chigutisaurid taxa compsocerops cosgriffi and kuttycephalus triangularis a critical review of triassic temnospondyls of the p g basin indicates that the affinities of s rajareddyi and k triangularis are somewhat uncertain and discovery of further material is necessary to establish their relationships among similar temnospondyls of the world it is also noted that b maleriensis is displaced by the two chigutisaurid genera and species at the carnian norian boundary thus p g basin is unique in having pangaean metoposaurids and exclusively gondwanan chigutisaurids in successive faunal zones within the same formation significantly the end of carnian is marked by the demise of metoposaurids in india as well as in africa and europe in north america their size appears to have diminished during that time

early triassic terrestrial tetrapod fauna a review abstract the permian triassic mass extinction ptme ca 252 mya was one of the most severe biotic crises of the phanerozoic eliminating 90 of marine and terrestrial species this was followed by a long period of recovery in the early and middle triassic which revolutionised the structure of both marine and terrestrial ecosystems triggering the new ecosystem structure of the mesozoic and cenozoic entire new clades emerged after the mass extinction including decapods and marine reptiles in the oceans and new tetrapods on land in both marine and terrestrial ecosystems the recovery is interpreted as stepwise and slow from a combination of continuing environmental perturbations and complex multilevel interaction between species in the new environments as ecosystems reconstructed themselves here we present a review of early triassic terrestrial tetrapod faunas geological formations and outcrops around the world and provide a semi quantitative analysis of a data set of early triassic terrestrial tetrapods we identify a marked regionalisation of early triassic terrestrial tetrapods with faunas varying in both taxonomic composition and relative abundance according to palaeolatitudinal belt we reject the alleged uniformity of faunas around pangaea suggested in the literature as a result of the hot house climate in addition we can restrict the tetrapod gap of terrestrial life in the early triassic to palaeolatitudes between 15 n and about 31 s in contrast to the earlier suggestion of total absence of tetrapod taxa between 30 n and 40 s there was fairly strong provincialism following the ptme according to cluster analysis of a taxon presence matrix entirely consistent with early triassic palaeobiogeography unexpectedly the overall pattern for early triassic terrestrial tetrapod faunas largely reflects that of the late permian suggesting that the recovery faunas in the early triassic retained some kind of imprint of tetrapod distributions according to palaeogeography and palaeoclimate despite the near total extinction of life through the ptme

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

climate signals in tree ring width density and δ13c from larches in eastern siberia russia abstract we present the first and longest 413 years dataset on stable carbon isotope ratios in tree ring cellulose 13c tree ring width trw and maximum latewood density mxd obtained from larch trees growing on permafrost under continental climate in the suntar khayata mountain ridge in eastern siberia russia with this first study we calibrate tree ring parameters against climate quantities and based on these results assess the potential added value of mxd and especially of 13c complementing trw analysis for future climate reconstruction purposes 13c chronologies were corrected for human induced changes in atmospheric co2 since ad 1800 two different approaches were compared i a correction referring merely to the decline in atmospheric 13c 13catm and ii a correction additionally accounting for the increase in atmospheric partial pressure of co2 13c chronologies are characterized by strong signal strength with only 4 trees representing the population signal at the site mean inter series correlation 0 71 and eps 0 90 13c variation shows low similarity to trw and mxd while correlation between trw and mxd is highly significant correlation analysis of tree ring parameters with gridded instrumental data climate research unit cru ts 2 1 over the ad 1929 2000 calibration period demonstrates that trw and mxd react as reported from other sites at cold and humid northern latitudes precipitation plays no significant role but strong dependencies on monthly mean maximum and minimum temperatures particularly of the current summer june to august are found up to r 0 60 p

correlation and causation in tree ring based reconstruction of paleohydrology in cold semiarid regions this paper discusses ways in which the tree ring based reconstruction of paleohydrology can be better understood and better utilized to support water resource management especially in cold semi arid regions the relationships between tree growth as represented by tree ring chronologies trcs runoff q precipitation p and evapotranspiration et are discussed and analyzed within both statistical and hydrological contexts data from the oldman river basin omrb alberta canada are used to demonstrate the relevant issues instrumental records of q and p data were available while actual et was estimated using a lumped conceptual hydrological model developed in this study correlation analysis was conducted to explore the relationships between trcs and each of q p and et over the entire historical record globally as well as locally in time within the wet and dry subperiods global and local correlation strengths and linear relationships appear to be substantially different this outcome particularly affects tree ring based inferences about the hydrology of wet and dry episodes when reconstructions are made using regression models important findings include i reconstruction of paleoq may not be as credible as paleop and paleoet ii a moving average window of p and et larger than one year might be necessary for reconstruction of these variables and iii the long term mean of reconstructed p q and et leads us to conclude that there is uncertainty about the past climate and finally we suggest using the topographic index to pre judge side suitability for dendrohydrological analysis this article is protected by copyright all rights reserved

reconstructed summer palmer drought severity index since 1850 ad based on δ13c of larch tree rings in eastern siberia summary we present a tree ring reconstruction of palmer drought severity index pdsi in ust maya region 60 00 n 133 49 e central part of eastern siberia using total ring tr widths and latewood lw 13c chronologies from larch trees 1850 2008 ad summer jja pdsi was correlated positively and negatively with the tr widths and lw 13c respectively using a multiple liner regression approach we reconstructed summer pdsi using the time series of tr widths and lw 13c the reconstruction showed an interannual to decadal wet dry fluctuation with several moist periods before 1950s and a severe drought event from 1991 to 1993 comparison of the reconstruction with reconstructed july pdsi for the yakutsk region 300 km northwest of ust maya showed heterogeneous changes in the mean states of soil moisture but synchronous year to year changes these results indicate that regional studies are quite important to precisely depict the spatio temporal variability of hydrological changes in the central part of eastern siberia

illite smectite structural changes during metamorphism in black cambrian alum shales from the baltic area illite smectite i s from cambrian black shale of both early diagenetic and anchimetamorphic grade was investigated to determine the mechanism of the clay transformation the layer sequences the distribution of thicknesses of coherent scattering domains csds and the three dimensional ordering were determined by x ray diffraction xrd the proportions of cis vacant cv and transvacant tv 2 1 layers were determined by thermal analysis and the proportion and distribution of interlayer ammonium by xrd and by infared spectroscopy ir the structural formulae were determined from total chemical analysis and mossbauer and 27al nmr spectroscopies and the particle shape and size investigated by atomic force microscopy afm in the early diagenetic samples the i s is composed of two phases one of which contains 0 05 and the other 0 25 smectite s interlayers the first phase does not change during metamorphism in the second phase 0 20 s are converted to tobelite t layers through fixation of formula 1 but the i layers are not changed simultaneously the proportion of cv layers changes from 0 18 to 0 02 and the tetrahedral substitution of al for si is parallel to the increase in t layers all i interlayers contain 0 75k per o10 oh 2 further more the metamorphism results in increasing mean thickness of csds from 5 1 6 8 nm for the low diagenetic samples to 6 7 8 4 nm for the anchimetamorphic samples we conclude that the tobelitization was accompanied by transformation of cv to tv 2 1 layers adjacent to the smectite interlayers and formation of tv layers adjacent to the newformed tobelite interlayers in otherwise intact crystallites this mechanism only partly resembles the tobelitization previously observed in the upper jurassic north sea oil source rocks i s in these rocks contained tv 2 1 layers and t interlayers formed through solid state al for si substitution in the tetrahedral sheet and by ammonium fixation in the corresponding interlayers these different mechanisms are probably because the north sea i s originated from weathered illite like the cambrian high illitic phase whereas the cambrian low illitic phase undergoing the transformation originated from cv smectite of volcanic origin the results indicate that the illitization in oil source rocks is linked to oil generation and that it deviates from the illitization in other rocks because of the supply of ammonium formed during oil generation and the fixation of this ammonium in the former smectite interlayers 1 embed tex math 1 gif

geological controls on the quality of coals from the west shandong mining district eastern china abstract the basic coal quality parameters coal petrology mineralogy and geochemistry were investigated for coal seams 2 3 and 4 permian shanxi formation and 11 12 13 and 15 carboniferous taiyuan formation of the xinwen and feicheng coal fields in the west shandong mining district east china rank parameters indicate a high volatile c to b bituminous rank for the shandong coal coal from the zhaizhen and cha zhuang mines is characterised by high vitrinite and low middle inertinite and liptinite contents inertinite contents show an increase towards the top of the stratigraphic sequence from coal seams 15 13 and 11 to coal seams 4 and 2 this trend may be related to a stratigraphic trend characterised by the evolution of relatively more reducing conditions of the synsedimentary coal forming environment in the early taiyuan coals marine influenced lower delta plain to more oxidising paleoenvironments of the upper shanxi coal seams upper delta plain major mineral phases present in the shandong coal are quartz kaolinite pyrite and calcite traces of other primary minerals dolomite ankerite illite opal feldspars and marcasite and weathering products gypsum melanterite and hematite can be found in several coal seams the lower permian coal seams two to four have a lower mineral content 8 14 ash db than the upper carboniferous coal seams 15 37 ash db owing to the lower proportions of quartz and sulphide mineral the occurrence and distribution of the different minerals in the shandong coal indicates a paragenetic sequence characterised by an early syngenetic stage detrital minerals framboidal euhedral and massive cell filling pyrite ankerite neomorphic quartz and kaolinite middle and late syngenetic stages radial and fibrous marcasite aggregates massive pyrite and an epigenetic stage carbonates and sulphides as cleat filling a clear differentiation exists between the shanxi and the taiyuan coal seams based on the higher sulphide contents of the taiyuan coal 3 3 to 6 2 s db compared with the shanxi coal 0 4 to 0 8 s db this differentiation is related to marine influence on the depositional environment of coal seams 11 to 15 which has been reported by earlier studies vertical variations of the abundance of major and trace elements are discussed on the basis of this differentiation an epigenetic external enrichment of ge mo and u at the top of most of the coal seams is observed and major and trace element affinities are deduced for the west shandong coal

fixed ammonium in clays associated with crude oils abstract the association of ammonium nh 4 silicates with organic rich sedimentary environments has stimulated interest in the chemical cycle of n and its possible application as an indicator of in situ organic maturation reactions or crude oil migration fixed nh 4 in clay minerals was determined from three hydrocarbon occurrences of similar depositional environment but different ages depth and thermal maturity to determine whether anomalously high nh 4 substitution occurs near mature hydrocarbons results show higher fixed nh 4 concentrations in marginally mature mudstones than in immature sediments the highest fixed nh 4 concentrations were found in clays from sandstone reservoirs containing migrated crude oil fixed nh 4 in clays from holocene oil seep sediments in the gulf of mexico continental slope offshore louisiana averages 0 08 wt and increases with depth in shallow cores 420 cm reflecting an early diagenetic trend that is apparently not influenced by migrating crude oil programmed pyrolysis shows that the sediments are thermally immature av t max 419 c high hydrogen index values av 359mg g are the result of biodegraded crude oil and a high oxygen index av 182mg g reflects the presence of authigenic carbonate fixed nh 4 averages 0 16 wt in wilcox group eocene mudstones enclosing two sandstone reservoirs at fordoche field onshore louisiana in comparison to these mudstones anomalously high nh 4 fixation appears to occur in reservoir clay minerals pyrolysis shows that the sediments are marginally mature for crude oil generation av t max 432 c average hydrogen index 187 mg g and oxygen index values 75 mg g are consistent with oil prone type ii and type iii kerogen increased pyrolysis production index values and solvent extraction shows the presence of migrated crude oil this suggests that a reaction which releases nh 3 during crude oil generation or migration is recorded bynh 4 substitution in clays fixed nh 4 and total organic carbon toc at fordoche field show no statistically significant correlation suggesting that nh 4 substitution in clay minerals is not simply related to the amount of organic matter in the section but is also influenced by the presence of crude oil once nh 4 has been fixed in clays it is a more stable hydrocarbon proximity indicator than pore fluid tracers because it is less influenced by later chemical or geological changes

global triassic tetrapod biostratigraphy and biochronology abstract eight temporally successive assemblage zones of tetrapod fossils provide the basis for dividing triassic time into eight land vertebrate faunachrons these land vertebrate faunachrons their type assemblage zones and their approximate correlation to the standard global chronostratigraphic scale are ascending order 1 lootsbergian lystrosaurus assemblage zone balfour katberg and burgersdorp formations karoo basin south africa late dorashamian induan 2 nonesian cynognathus assemblage zone burgersdorp formation karoo basin south africa olenikian 3 perovkan shansiodon assemblage zone donguz formation russian urals anisian 4 berdyankian mastodonsaurus assemblage zone bukobay formation russian urals ladinian early carnian 5 otischalkian paleorhinus assemblage zone chinle group chinle basin usa late early to early late carnian 6 adamanian rutiodon assemblage zone chinle group chinle basin usa latest carnian 7 revueltian pseudopalatus assemblage zone chinle group chinle basin usa norian 8 apachean redondasaurus assemblage zone chinle group chinle basin usa rhaetian the triassic land vertebrate faunachrons provide a framework for the correlation of triassic nonmarine deposits with a temporal resolution comparable to the seven triassic stage ages of the standard global chronostratigraphic scale

nitrogen isotope compositions of metasedimentary rocks in the catalina schist california implications for metamorphic devolatilization history abstract in the catalina schist subduction zone metamorphic complex california metasedimentary rocks show a decrease in n concentration and an increase in 15nair with increasing metamorphic grade lowest grade lawsonite albite rocks contain 632 185 ppm n with 15 n 1 9 0 6 whereas highgrade amphibolite equivalents contain 138 76 ppm n with 15 n 4 3 0 8 loss of n accompanied devolatilization reactions that evolved h2o rich c o h s n fluids through consumption of chlorite and phengitic white mica and production of mineral assemblages containing muscovite biotite garnet and kyanite whole rock n concentrations of up to 200 ppm in veins and pegmatites produced during high p t metamorphism reflect the redistribution of n during devolatilization and partial melting of the metasedimentary rocks bulk fluid rock n isotope fractionations 15n 15nfluid 15nrock of 1 5 1 were calculated with the rayleigh distillation equation taking into account variability in rock composition by comparison of samples with similar k2o concentrations these fractionations are similar to but slightly lower than published calculated fractionations for n2 nh4 exchange at the temperature range of 350 600 c over which most of the devolatilization occurred in the catalina schist approximately 3 4 to 2 25 the n systematics appear to be explained by n2 nh4 exchange and a devolatilization process intermediate in behavior to batch volatilization and rayleigh distillation the observed shifts in n concentration and 15n cannot be explained by nh3 nh4 exchange at these temperatures using the equilibrium models the distillation devolatilization process implicated in this study may govern the behavior of other trace elements partitioned into hydrous fluids during devolatilization e g b cs u similarity of the calculated fluid 15n 1 5 to 5 5 with compositions of natural gases inferred to be derived from metasedimentary sources indicates the possibility of using n as a tracer of large scale volatile transport

ammonium vermiculite in schists from the betic cordillera spain nh 4 bearing phases from pre permian schists of the internal zones of the betic cordillera spain have been characterized by x ray diffraction differential thermal analysis and thermogravimetry infrared spectroscopy and transmission analytical electron microscopy the content and distribution of nh 4 in these phases have been estimated by combining elemental analysis of n with mineral quantification based on x ray diffraction whole rock composition and electron microprobe data the obtained results indicate that the nh 4 content in vermiculite ranges between 0 5 and 1 0 wt leading to terms with nh 4 k in the interlayer the nh 4 content is 4 contents 0 04 wt through the complete sequence we interpret that initially contained in low grade dioctahedral mica nh 4 was incorporated in the structure of the trioctahedral phases formed at increasing metamorphic conditions the entry of nh 4 in the interlayer was favored in chlorite vermiculite mixed layered structures and transitional phases with vacancies in the a site vermiculite and weak cohesion between layers nh 4 appears to favor the formation of intermediate phases instead the direct transformation of chlorite to biotite

notes on the mechanisms of coal metamorphism in the pennsylvania anthracite fields abstract charred devolatilized megasporinite and featureless vitrinite with devolatilization pores filled with pyrolytic carbon suggest that eastern pennsylvania anthracites may have been altered by to localized episodes of metamorphism from superheated steam co2 co hydrocarbons in addition to the pervasive regional metamorphism based on the extant vitrinite textures the lack of mesophase anisotropic textures and on comparisons to laboratory studies of the thermoplasticity of bituminous coals the rank at the time of metamorphism would have been high volatile c or lowermost high volatile b bituminous the temperature of alteration would have been in the 350 400 c range corresponding to the critical point of steam 374 15 c and 22 1 mpa about 1 km depth it is speculated that while increased pressure would have prolonged the duration of fluid properties fluidity is still a transient property and the vitrinite would have returned to a solid state after a few hours the heat would have persisted dissipating over the course of days to months to years depending upon the depth and ambient pre heating geothermal gradient but contributing to the coal metamorphism long after the vitroplast solidified