coal petrology of coal seams from the leao butia coalfield lower permian of the parana basin brazil implications for coal facies interpretations abstract in the leao butia coalfield rio grande do sul the coal seams occur in the rio bonito formation guata group tubarao supergroup of the parana basin brazil and are of permian artinskian kungurian age this study is the first detailed investigation on the coal petrographic characterization of the coal bearing sequence in relation to the depositional settings of the precursor mires both in terms of whole seam characterization and in seam variations the study is based on the analyses of nine coal seams i2 ci l4 l3 l2 l1 s3 s2 s1 which were selected from core of borehole d 193 leao butia and represent the entire coal bearing sequence the interpretation of coal facies and depositional environment is based on lithotype maceral and microlithotype analyses using different facies critical petrographic indices which were displayed in coal facies diagrams the seams are characterized by the predominance of dull lithotypes dull banded dull the dullness of the coal is attributed to relatively high mineral matter inertinite and liptinite contents the petrographic composition is dominated by vitrinite 28 70 vol mmf and inertinite 30 vol mmf groups liptinite contents range from 7 to 30 vol mmf and mineral matter from 4 30 vol microlithotypes associations are dominated by vitrite duroclarite carbominerite and inertite it is suggested that the observed vertical variations in petrographic characteristics lithotypes microlithotypes macerals vitrinite reflectance were controlled by groundwater level fluctuations in the ancient mires due to different accommodation peat accumulation rates correlation of the borehole strata with the general sequence stratigraphical setting suggests that the alluvial fan system and the coal bearing mudstone succession are linked to a late transgressive systems tract of sequence 2 based on average compositional values obtained from coal facies diagrams a deposition in a limno telmatic to limnic coal facies is suggested

correlations between the classic parana and cape karoo sequences of south america and southern africa and their basin infills flanking the gondwanides du toit revisited

geochronology ar ar and k ar of the south atlantic post break up magmatism this work integrates the available geological information and geochronology data for the cretaceous recent magmatism in the south atlantic represented by onshore and offshore magmatic events including the oceanic islands along the transform faults and near the mid ocean ridge the analysis of the igneous rocks and their tectonic settings allows new insights into the evolution of the african and brazilian continental margins during the south atlantic opening following the abundant volcanism in the early cretaceous the magmatic quiescence during the aptian albian times is a common characteristic of almost all brazilian and west african marginal basins however rocks ascribed to the cabo granite 104 ma are observed in ne brazil in west africa sparse aptian albian ages are observed in a few coastal igneous centres in the se brazilian margin an east west alkaline magmatic trend is observed from pocos de caldas to cabo frio comprising igneous intrusions dated from 87 to 64 ma mafic dyke swarms trending nw also occur in the region extending from the cabo frio province towards the central brazilian craton on the west african side early cretaceous recent volcanism is observed in the walvis ridge 139 ma the st helena ridge 81 ma and the cameroon volcanic line early tertiary recent volcanic islands such as ascencion 1 0 0 65 ma tristao da cunha 2 5 0 13 ma and the st helena islands 12 ma most probably correspond to mantle plumes or hot spots presently located near the mid atlantic spreading centre within the south america platform and deep oceanic regions the following volcanic islands are observed the rio grande rise 88 86 ma abrolhos 54 44 ma the vitoria trindade chain no age trindade 2 8 1 2 ma and fernando de noronha 12 1 5 ma there are several volcanic features along the nw se trending cruzeiro do sul lineament from cabo frio to the rio grande rise but they have not been dated the only known occurrence of serpentinized mantle rocks in the south atlantic margin is associated with the saint peter and saint paul rocks located along the sao paulo fracture zone the cameroon volcanic line in nw africa is related to the magmatism that started in the late cretaceous and shows local manifestations up to the present the compilation of all available magmatic ages suggests an asymmetrical evolution between the african and south america platforms with more pre break up and post break up magmatism observed in the brazilian margin this is most likely to have resulted from the different geological processes operating during the south atlantic ocean opening shifts in the spreading centre and possibly the rising and waning of mantle plumes

volcanic stratigraphy of the quaternary la garrotxa volcanic field north east iberian peninsula this study was partially funded by the beca ciutat d olot and the european commission ft7 theme env 2011 1 3 3 1 grant 282759 vuelco

generation of gas and oil from coal and other terrestrial organic matter abstract late carboniferous permian sedimentary rocks contain the world s largest coal reserves which have generated and released gas but little if any oil in comparison organic matter deposited in lacustrine fluvial deltaic or brackish water sediments has sourced large quantities of waxy oils in countries such as china australia the u s a argentina venezuela and indonesia plus gas and condensate in deltas worldwide why is more oil coming from land derived organic matter disseminated in sediments than from the carboniferous permian coal beds which also are land deposits the answer appears to be in the hydrogen content and the ease of migration when organic matter and coals have high hydrogen contents relative to carbon they can form oil when the hydrogen is low mainly gas is formed most of the world s coal is low in hydrogen whereas much of the terrestrial organic matter disseminated in sediments is higher in hydrogen so it forms more oil also both gas and oil are adsorbed on coal more strongly than on the disseminated kerogen of sedimentary rocks this makes migration of oil out of the coal more difficult compared to migration from conventional shale source rocks

the effects of fire and water repellency on infiltration and runoff under mediterranean type forest abstract an investigation is being made into the relationship between forest fire and hillslope hydrology in the selva region of catalonia over a three year period at sites with a known fire history the major sites are on granite granodiorite or on sediments derived from these rocks at locations between santa christina d aro and santa coloma de farnes it appears that there is a general relationship between the type of organic profile found in a forest and the impact of fire in terms of loss of organic matter soil erosion hillslope hydrology and on the regeneration of the forest this paper summarises the results of about 150 rainfall simulation experiments and presents an overview of work carried out so far a major conclusion is that runoff processes are discontinuous and spatially structured due mainly to the effects of water repellency as a result of surface properties macropores hydrophobic behaviour and swelling four types of infiltration curve can be recognised at many locations infiltration increases with time during the early part of an experiment reaches a maximum value after about 30 minutes therupon subsequently decreasing this type of relationship can not be modelled with standard infiltration equations illustrations are given of sections through both burnt and unburnt soils to show how the hydrophobic effect influences water penetration it can be seen that infiltration patterns are similar for both burnt and unburnt soils and that micropores filled with organic matter are very important in conducting water through a water repellent surface layer the hydrophobic layer traps water in the bc horizon and prevents evaporation and loss by upwards capillary movement although the hydrophobic effects mean that small areas sometimes have a high runoff coefficient on larger areas there are many macropores and shrubs beneath which the soil is permeable and these trap runoff generated on the water repellent areas the main effect of fire is to illiminate the storage of water in the organic horizons several cm at first infiltration rates remain high but later these decrease as there is a reduction in porosity the sites having a moder type profile have better water retention properties more organic matter that survives the fire and a faster rate of vegetation recovery sites with a mor type profile can be degraded and erode if they are subject to disturbance the study provides another example of how on seemingly uniform slopes hydrological processes are structured by interactions with vegetation the patterns produced by these interactions survive the effects of fire

the kerogen type depositional environment and maturity of the irati shale upper permian of parana basin southern brazil abstract two samples from the upper and lower horizons of the irati oil shale of the parana basin brazil were sampled in a single borehole and analysed using organic petrography and geochemistry the results are interpreted in terms of the kerogen type maturity and depositional environment of the two horizons organic petrography shows the oil shales to be composed of a mineral groundmass mainly clay minerals carbonate and pyrite associated and sometimes impregnated with fluorescing organic material and disseminated phytoclasts humic material is fairly rare and mostly present as very small particles the liptinitic particles are mostly alginite a and b sporinite and more rarely resinite reflectance measurements upper seam 0 34 r0 lower seam 0 40 r0 indicate an equivalent rank of lignite sub bituminous coal astm i e immature with respect to oil and gas generation different organic geochemical methods rock eval pyrolysis solvent extraction gc and gc ms demonstrate both samples to be immature rich oil shales 100 114 kg ton containing type i kerogen of a dominantly bacterially degraded algal origin deposited in a lacustrine environment the presence of botryococcus suggests deposition under fresh brackish water conditions a tentative interpretation of the extract and vitrinite reflectance data suggests a maximum paleo burial of between 1 3 and 2 8 km for the analysed section of the irati formation

crustal thickness mapping of the central south atlantic and the geodynamic development of the rio grande rise and walvis ridge abstract the origin of the rio grande rise and walvis ridge within the central south atlantic and its implications for the separation of south america and africa during the cretaceous are controversial the recent report of the discovery from submersible sampling of continental material of proterozoic age on the rio grande rise suggests that the existing explanation involving ocean ridge mantle plume interaction or simply excess on ridge magmatism for the formation of the rio grande rise and walvis ridge needs to be re examined we use gravity anomaly inversion to map crustal thickness for the central south atlantic area encompassing the rio grande rise walvis ridge and adjacent south american and african rifted continental margins we show that the rio grande rise consists of three distinct bodies of anomalously thick crust western central and eastern separated by normal thickness oceanic crust the central rio grande rise forms a large elliptical body with maximum crustal thickness of 25 km the walvis ridge also has a maximum crustal thickness of 25 km but has a narrower and more linear geometry we use plate reconstructions to restore maps of crustal thickness and magnetic anomaly to early cretaceous times to examine the development of the rio grande rise and walvis ridge these restorations together with ages of magmatic addition suggest that the central rio grande rise and walvis ridge formed a single body between 90 and 80 ma located on the ocean ridge plate boundary similar to iceland today on the basis of crustal thickness mapping the plate restorations and the magmatic ages we propose that the rio grande rise was fragmented into its 3 parts and separated from walvis ridge by at least 4 ocean ridge jumps during the opening of the south atlantic ocean between approximately 90 and 50 ma plate reconstructions of crustal thickness showing rotated structural lineaments imply that the separation of eastern rio grande rise and walvis ridge was highly complex involving simultaneous crustal extension and magmatic addition we propose that the continental material reported on the rio grande rise if not drop stones was isolated from the main continental land mass and transported into the ocean by these ridge jumps during the cretaceous formation of the south atlantic

sequence stratigraphy of paralic coal bearing strata an overview abstract sequence stratigraphy arose in the late 1980s to fundamentally change the science of stratigraphy former practice of labeling formations and erecting stratigraphic columns gave place to a dynamic genetic stratigraphic analysis where the main concern is about understanding the history of sedimentation and to establish models able to predict facies born and mainly applied to an environment of petroleum prospecting and exploration sequence stratigraphy has gained entrance to other branches of sedimentary geology the present paper gives a short introduction to sequence stratigraphic concepts and shows an overview of its application on coal bearing strata two case studies one from the early permian coals of the parana basin brazil and one from the lower cretaceous coals of the western canada sedimentary basin illustrate the concepts

a new stratigraphic framework built on u pb single zircon tims ages and implications for the timing of the penultimate icehouse parana basin brazil

petrology and chemistry of permian coals from the parana basin 1 santa terezinha leao butia and candiota coalfields rio grande do sul brazil the current paper presents results on petrological and geochemical coal seam characterization in permian coal bearing strata from the parana basin southern brazil sequence stratigraphic analysis shows that peat accumulation in permian time was closely linked to transgressive regressive cycles with peat accumulation occurring in a predominantly back barrier lagoonal setting coal petrographic analysis indicates subbituminous coals at candiota and leao butia and high volatile bituminous coals at santa terezinha where locally the coal seams are thermally altered by volcanic intrusions petrographic composition is highly variable with seams at candiota and santa terezinha frequently enriched in inertinite chemical analyses indicate that all coals are mineral matter rich mean 49 09 wt with sio2 and al2o3 dominating as determined by icp aes quartz is also the predominant mineral detected by x ray diffraction where it is associated with feldspar kaolinite and hematite and iron rich carbonates the results from scanning electron microscopy are broadly consistent with the bulk chemical and mineralogical analysis quartz and clays are common in all samples analyzed other minerals observed were amongst others carbonates calcite siderite ankerite pyrite monazite kaolinite barite sphalerite rutile and quartz of volcanic origin the distribution of trace elements is well within the range typical for coal basins of other areas despite the fact that the parana basin coals are very high in ash yields the average concentrations for elements of environmental concern as b be cd co cr cu hg li mn mo ni pb sb se tl u v zn are similar to or less than the mean values for u s coal however considered on an equal energy basis parana basin coals will produce in combustion 5 to 10 times the amount of most elements compared to an equal weight us coal concentrations of major and trace elements such as fe b and s appear to be controlled by depositional setting with increasing values in coal seams overlain by brackish marine strata hierarchical cluster analysis identified three groups of major minerals and seven groups of trace elements based on similarity levels on a regional scale the coalfields can be separated by the differences in rank candiota and leao butia versus santa terezinha and by applying discriminant analysis based on 4 trace elements li as sr sb highest rb and sr values occur at candiota and are linked to syngenetic volcanism of the area whereas high y and sr values at santa terezinha can be related to the frequent diabase intrusions in that area

apatite fission track analysis apatite fission track aft analysis has been widely used during the past 30 years to constrain the low temperature thermal histories of many igneous metamorphic and sedimentary rocks in a wide range of geological settings applicable geological settings include orogenic belts rifted margins faults sedimentary basins cratons and mineral deposits the types of geologic problems that can be addressed include the timing and rates of tectonic events sedimentary basin evolution the timing of hydrocarbon generation and ore mineralization the absolute age of volcanic deposits the effects of major climatic changes on the near surface geothermal gradient and long term landscape evolution early work by naeser 1967 and wagner 1968 1969 first established the basic procedures that enabled the fission track dating method to be applied routinely to these geologic problems fleischer et al 1975 summarized the early studies of the broader discipline of nuclear track detection in different solid state materials more recent comprehensive overviews of fission track applications have been provided by naeser and mcculloh 1989 wagner and van den haute 1992 gallagher et al 1998 van den haute and de corte 1998 dumitru 2000 and gleadow et al 2002 etched natural fission tracks in several apatite grains are shown in figure 1 successful aft analysis is limited by the following 1 the availability of apatite from which useful aft data can be obtained often due to a lack of apatite of sufficient grain size and quality within available rock types or alternatively the lack of available rock samples due to minimal outcrop exposure or other reasons 2 economic considerations in terms of the time and money required to obtain sufficient aft data 3 the inherent limitations of aft data to resolve geological thermal history information often related to limited numbers of accumulated spontaneous fission tracks due to

evolution of overland flow after a severe forest fire point reyes california abstract forest fires on granitic soils often increase overland flow and erosion runoff generation was monitored on a small hillslope plot on mt vision near point reyes peninsula california after it had been burned by a wildfire on october 3 1995 after the fire the ground surface was covered with up to 2 cm of ash which overlaid a 5 20 cm thick hydrophobic water repellent soil layer we used nine recording tensiometers to monitor soil water potentials during infiltration and runoff surface runoff rates were determined by diverting the flow into a collection tank the subsurface flow through the upper 6 cm of soil was collected and measured in a second tank the surface runoff was diverted to a tank in order to record its rate the initial intense rainfall infiltrated into the base of the ash bed here the hydrophobicity limited deeper penetration and led to both subsurface and shallow saturation overland flow the preferential flow paths through the ash layer contributed to deeper water penetration as the ash was eroded and consolidated with successive rainstorms the preferential flow paths clogged the infiltration capacity reduced thus preventing the storage of shallow permeable soil therefore the runoff generation changed to hortonian overland flow correspondingly the runoff ratio increased from approximately 0 2 during the early storms to 0 8 during intense rain bursts these results suggest that runoff mechanisms evolve simultaneously with the eroding soil surface

the impact of over 100 years of wildfires on mercury levels and accumulation rates in two lakes in southern california usa in southern california usa wildfires may be an important source of mercury hg to local watersheds hg levels and hg accumulation rates were investigated in dated sediment cores from two southern california lakes big bear lake and crystal lake located approximately 40 km apart between 1895 and 2006 fires were routinely minimized or suppressed around big bear lake while fires regularly subsumed the forest surrounding crystal lake mean hg concentrations and mean hg accumulation rates were significantly higher in crystal lake sediments compared to big bear lake sediments hg levels crystal lake 220 93 ng g 1 big bear lake 92 26 ng g 1 hg accumulation crystal lake 790 1 200 g m 2 year 1 big bear 240 54 g m 2 year 1 in crystal lake the ratio between post 1965 and pre 1865 hg concentrations was 1 1 and several spikes in hg levels occurred between 1910 and 1985 given the remote location of the lake the proximity of fires and the lack of point sources within the region these results suggested wildfires rather than industrial sources were a continuous source of hg to crystal lake over the last 150 years

the denudation history of the onshore continental margin of se brazil inferred from apatite fission track data a suite of 68 new apatite fission track analysis results from the onshore rift margin in southeast brazil are presented some of the results reflect resetting related to the eruption of the parana continental flood basalt 130 ma and four others are directly related to late cretaceous magmatism 80 ma the majority of the results were obtained from precambrian basement rocks and sediments from the parana basin the fission track ages broadly increase inland from 60 90 ma on the coastal plain to 300 ma in the continental hinterland the track length distributions show a characteristic trend being negatively skewed at the coast and showing increasing bimodality inland except for the oldest samples which are more unimodal these trends do not reflect rift related heating and resetting but are the result of protracted denudation since the opening of the south atlantic the results are consistent with more than 3 km of exhumation on the coastal plain but little more than 1 km in the hinterland the topographic morphology in the northern region of the study area is complex and is clearly influenced by structure and bedrock lithology for the region further south model calculations of the isostatic response to the denudation suggest that isostatic rebound makes a minor contribution to the long wavelength topography unless the flexural rigidity is more than 1025 n m in this case the initial elevation of the rift margin would need to be 2 5 km in order to accommodate the amount of denudation inferred from the fission track data however it is possible that the effective flexural rigidity varies across the margin becoming greater in the continental interior alternatively the broad scale wavelength topography may be the result of magmatic underplating related to the parana continental flood basalt event if so estimates of the volume of magma generated would need to be revised upward by as much as a factor of 5

fission track dating of phosphate minerals and the thermochronology of apatite several phosphate minerals have been investigated for their usefulness in geochronology and thermochronology by the fission track method of these apatite ca5 po4 3 f cl oh has proved pre eminently suitable for this purpose for reasons discussed below apatite was one of the first minerals amongst many others to be investigated for fission track dating by fleischer and price 1964 and has subsequently become by far the most important of all the minerals used for dating by this method the usefulness of apatites for fission track dating arises from their near universal tendency to concentrate uranium within their structure at the time of crystallization and their widespread occurrence in all of the major rock groups price and walker 1963 first recognized the possibility that the accumulation of radiation damage tracks in natural minerals from the spontaneous nuclear fission of 238u within their lattices could be used for geological dating they also demonstrated that a simple chemical etching procedure served to enlarge these fission tracks to optical dimensions so that they could be observed and measured under an ordinary optical microscope price and walker 1962b 1963 this simple procedure quickly opened the way for a wide range of nuclear particle track studies in natural minerals and glasses e g fleischer et al 1975 the most important of which was fission track dating fleischer et al 1964 also showed that spontaneous or fossil fission tracks provided an explanation for various anomalous etch pits in apatite which had puzzled crystallographers over many years the essence of a fission track age determination involves measuring the number of tracks that have accumulated over the lifetime of the mineral along with an estimate of the amount of uranium that is present knowing the rate of spontaneous fission decay a geological age can be calculated detailed

co2 storage potential of south african coals and gas entrapment enhancement due to igneous intrusions abstract methane outburst events have occurred in some underground coal mines of south africa such as those in twistdraai mine in the highveld coalfield in the early 1990s occurrences of methane outbursts suggest that high gas content in adsorbed and free phase might be present in some sections of the coal seams coal seams might also be friable in those sections allowing pulverisation during outburst the survey of gas outburst events indicates that the locations of high gas emissions were mainly in the vicinity of the igneous intrusions mainly dolerite intrusions these intrusions are a result of post depositional volcanism into coal seams in some major coalfields of south africa such as the highveld coalfield this study was undertaken firstly to investigate potential locations for the occurrence of coal seam gas in south african coal seams with respect to the igneous intrusions and their enhancement effect on gas release and storage of these coals secondly it was thought that as the metamorphosed coals with high ash content were not economically viable for mining they might be potentially suitable for co 2 disposal measurements on 14 coal samples taken in an underground coal mine at various distances from a dolerite dyke show that the adsorption and porosity properties of metamorphosed coals have been enhanced thus increasing their gas storage capacity diffusivity results show that dolerite intrusions would act as enclosures and gas traps for storage of gas gas diffusivity was greater in coals near the dyke by a factor of two in general it is expected that the co 2 storage and gas flow properties of such coals be enhanced due to the heating effect of intrusions making the coals more appealing for possible future sequestration of co 2 from anthropogenic sources

time and temperature in petroleum formation application of lopatin s method to petroleum exploration n v lopatin in the soviet union has developed a method for taking both time and temperature into account as factors in thermal maturation of kerogen lopatin s time temperature index of maturity tti values correlate with the thermal regimes corresponding to generation and preservation of hydrocarbons because such information is potentially of great interest for oil exploration a calibration and evaluation have been made of lopatin s method within the limitations of the data presently available the following statements can be made 1 the rate of the chemical reactions involved in thermal maturation of organic material appears to double with every 10 c 18 f rise in temperature 2 threshold values of lopatin s time temperature index of maturity tti are 15 onset of oil generation 75 peak oil generation 160 end oil generation 500 40 oil preservation deadline 1 000 50 oil preservation deadline 1 500 wet gas preservation deadline 65 000 dry gas preservation deadline 3 tti values calculated from lopatin reconstructions consistently agree with other maturation parameters commonly used by petroleum geochemists potential applications of lopatin s method for oil exploration include timing of oil generation calculation of volume of hydrocarbons generated within a basin and determination of economic deadlines

the effects of log erosion barriers on post fire hydrologic response and sediment yield in small forested watersheds southern california wildfire usually promotes flooding and accelerated erosion in upland watersheds in the summer of 1999 a high severity wildfire burned a series of mixed pine oak headwater catchments in the san jacinto mountains of southern california log erosion barriers lebs were constructed across much of the burned area as an erosion control measure we built debris basins in two watersheds each about 1 ha in area one with lebs the other without to measure post fire hydrologic response and sediment yield and to evaluate the effectiveness of the lebs the watersheds are underlain by granitic bedrock producing a loamy sand soil above large extents of weathered bedrock and exposed core stones tors on the surface measured soil water repellency was similar over the two catchments rain gauges measured 348 mm of precipitation in the first post fire year the ephemeral stream channels experienced surface flow after major rainstorms and the source of the water was throughflow exfiltration at the slope channel interface post fire overland flow produced some rilling but hillslope erosion measured in silt fences away from any lebs was minor as was sediment accumulation behind the lebs stream channels in the catchments exhibited minor net scour water yield was much greater in the leb treated watershed this resulted in 14 times more sediment yield by weight than the untreated watershed average soil depths determined by augering were nearly double in the catchment without the lebs compared with the treated watershed this suggests that differences in water and sediment yield between the two catchments are due to the twofold difference in the estimated soil water holding capacity in the untreated watershed it appears that the deeper soils in the untreated watershed were able to retain most of the precipitation releasing less water to the channels and thereby reducing erosion and sediment yield thus the test of leb effectiveness was inconclusive in this study because soil depth and soil water holding capacity may have masked their performance

the contrasted response of ash to wetting abstract after a wildfire the soil is covered by ash ash properties depend on vegetation type amount of fuel and fire intensity the ash layer controls the post fire soil hydrologic response but little is known about the effect of ash thickness and ash type on infiltration which is relevant for post fire runoff and soil losses and for ecosystems rehabilitation and restoration this paper analyses the role of i ash type black or white ii thickness 5 15 and 30 mm thick and iii temporal variation 0 15 and 40 days under three simulated rain events 55 mm for 1 h on soil surface hydrology the rainfall was simulated on 0 25 m2 plots and time to ponding runoff and runoff discharge were measured the infiltration rates the initial infiltration rate f0 the steady state infiltration rate fc and the infiltration decay factor k were calculated and the horton infiltration equation applied the results show that soils covered with white ash doubled the runoff rates of soils covered with black ash in general runoff decreases as the ash thickness increases and the runoff decreases with the number of rainfall events after the fire in plots covered with white ash ponding time and k are positively correlated by the ash thickness and f0 and fc are correlated by the rainfall events in three runs ash type and ash depth are key factors on the soil hydrology after a wildfire

a new u pb zircon age dating and palynological data from a lower permian section of the southernmost parana basin brazil biochronostratigraphical and geochronological implications for gondwanan correlations abstract index species useful for correlations with the international stratigraphical column are rare or absent in the pennsylvanian permian strata of the parana basin in brazil preventing accuracy in geochronologic assignments besides absolute datings are very scarce in comparison with other gondwana basins this paper presents palynological data from an outcrop on the surroundings of the candiota coal mine southmost brazil from several levels of the rio bonito and palermo formations the presence of certain index species of spore pollen allowed the recognition of two permian palynozones the vittatina costabilis and the lueckisporites virkkiae zones furthermore u pb in zircons from a volcaniclastic level interbedded in the coal strata of the former unit was analyzed through la mc icp ms method providing a new absolute age dating of 281 4 3 4 ma cisuralian early permian this dating is assumed as the oldest occurrence of the l virkkiae zone in parana basin which contains index species that are widespread in other gondwana basins a well distributed surface boundary occurs in this section also allowing local and regional correlations these new biostratigraphical and geochronological data are integrated in order to offer a deep analysis on the stratigraphical significance for correlations across the occidental gondwana

thermal and depositional history of early permian rio bonito formation of southern parana basin brazil abstract the parana basin is a large volcano sedimentary basin with a complex depositional history from ordovician to the cretaceous period during permian significant amounts of organic rich beds accumulated within the rio bonito and irati formations representing deposition in coastal deltaic and barrier lagoon and shallow marine environments respectively in this work the thermal history of these beds is examined from 16 vitrinite reflectance analyses of coal beds rio bonito formation integrated with previous data on coal rank and 21 apatite fission track aft analyses collected from 17 well profiles in the south of the parana basin coal samples showed three different maturity levels two with reflectances of 0 4 0 6 and 0 6 0 8 rr formed by the natural burial history of the basin the latter is restricted to the torres syncline area in contrast the third group reached much higher values 1 0 5 0 rr related to intrusive igneous rocks the aft data show thermal consistency with the reflectance values the sandstone samples related to the two lower reflectance patterns were partially reset preserving aft ages older than the stratigraphic age of the bed otherwise the samples severely affected by the magmatism have cretaceous and early cenozoic ages but some were much younger than the last magmatic event implying deep burial before cooling onset the mean track length distribution of the partially reset samples is short due to the inheritance of tracks preserved from basement cooling history however the population of fully reset samples gives crucial information on the maximum temperature reached and the age when cooling started at these conditions around 1 0 to 3 0 km of the parana basin sequences would have been removed from the surface of the studied areas by erosion since cretaceous regional variations in the amounts of removed sections were controlled by the structural framework mostly regional nw se and ne sw oriented structures

sediment availability on burned hillslopes 1 erodibility describes the inherent resistance of soil to erosion hillslope erosion models typically consider erodibility to be constant with depth this may not be the case after wildfire because erodibility is partly determined by the availability of noncohesive soil and ash at the surface this study quantifies erodibility of burned soils using methods that explicitly capture variations in soil properties with depth flume experiments on intact cores from three sites in western united states showed that erodibility of fire affected soil was highest at the soil surface and declined exponentially within the top 20 mm of the soil profile with root density and soil depth accounting for 62 of the variation variation in erodibility with depth resulted in transient sediment flux during erosion experiments on bounded field plots material that contributed to transient flux was conceptualized as a layer of noncohesive material of variable depth dnc this depth was related to shear strength measurements and sampled spatially to obtain the probability distribution of noncohesive material as a function of depth below the surface after wildfire in southeast australia the initial dnc ranged from 7 5 to 9 1 mm which equated to 97 117 mg ha 1 of noncohesive material the depth decreased exponentially with time since wildfire to 0 4 mm or 5 mg ha 1 after 3 years of recovery the results are organized into a framework for modeling fire effects on erodibility as a function of the production and depletion of the noncohesive layer overlying a cohesive layer

geomorphic complexity and sensitivity in channels to fire and floods in mountain catchments abstract fires and floods are important drivers of geomorphic change while the hydrologic and geomorphic effects of fires have been studied at the hillslope scale we have much more limited data on post fire runoff channel changes and inferred or measured sediment storage and delivery at larger scales in this study we intensively documented channel changes over four years in two very similar 15 km2 catchments in the northern colorado front range skin gulch and hill gulch that were burned primarily at high and moderate severity in june 2012 ten and 11 cross sections and longitudinal profiles along the lower channel network were repeatedly surveyed in skin gulch and hill gulch respectively summer thunderstorms generally caused deposition in the valley bottoms while incision resulted from the intervening baseflows and spring snowmelt but a very high intensity summer thunderstorm in skin gulch just one week after burning caused much more deposition than in hill gulch fifteen months after burning both watersheds experienced an exceptional long duration flood resulting from a multi day rainstorm with a several hundred year recurrence interval this removed nearly all of the deposited post fire sediment along with some of the older valley bottom deposits the expansion and coarsening of the channel has greatly decreased the geomorphic sensitivity of both watersheds to future floods and eliminated the more typical and persistent post fire depositional signature the channel changes in skin gulch after the fire and long duration flood were much greater than in hill gulch and this can be attributed to the much greater sediment deposition in skin gulch shortly after the fire reduced geomorphic sensitivity in hill gulch resulting from a large erosional flood in 1976 and the spatial distribution of burn severity and storm rainfalls leading to lower peak flows in hill gulch these results suggest that fires in the rocky mountains can trigger significant and dynamic hillslope and channel changes over sub decadal timescales but unusually long or intense rainstorms can cause larger and more persistent changes regardless of whether a catchment has recently burned

chemical and petrographical characterization of feed coal fly ash and bottom ash from the figueira power plant parana brazil abstract the aim of the present study is the petrographic and chemical characterization of the coal at the figueira power plant parana brazil prior and after the beneficiation process and the chemical characterization of fly and bottom ashes generated in the combustion process petrographic characterization was carried out through maceral analysis and vitrinite reflectance measurements chemical characterization included proximate analysis determination of calorific value and sulphur content ultimate analysis x ray diffraction x ray fluorescence inductively coupled plasma mass spectrometry icp ms and inductively coupled plasma atomic emission spectrometry icp aes analysis and determination of total organic carbon toc content vitrinite reflectance analyses indicate a high volatile b c bituminous coal 0 61 to 0 73 rrandom maceral analyses show predominance of the vitrinite maceral group 51 6 to 70 9 vol m m f except of the run of mine rom coal sample the average calorific value of the coals is 5205 kcal kg and ash yields range from 21 4 to 38 1 wt the mineralogical composition x ray diffraction of coals includes kaolinite quartz plagioclase and pyrite whereas fly and bottom ashes are composed by mullite ettringite quartz magnetite and hematite analyses of major elements from coal fly and bottom ashes indicate a high sio 2 al 2 o 3 and fe 2 o 3 content trace elements analysis of in situ and rom coals by icp ms and icp aes show highest concentration in zn and as most of the toxic elements such as as cd cr mo ni pb and zn are significantly reduced by coal beneficiation considering the spatial distribution of trace elements in the beneficiated coal samples which were collected over a period of three months there appears to be little variation in cd and zn concentrations whereas trace elements such as as mo and pb show a larger variation in the fly and bottom ashes the highest concentrations of trace elements were determined for zn and as when compared with trace element concentrations in the feed coal fly ashes show a significant enrichment in most trace elements as b be cd co cr cu li mn mo ni pb sb tl and zn suggesting a predominantly volatile nature for these elements in contrast sn is distributed evenly within the different ash types whereas u shows depleted concentration in both bottom and fly ash samples according to the international classification of in seam coals the cambui coals are of para ortho bituminous rank of low grade except for the rom sample and are characterized by the predominance of vitrinite macerals

regional coalification pattern of lower cretaceous coal bearing strata rocky mountain foothills and foreland canada implications for future exploration abstract the regional coalification pattern of lower cretaceous strata in parts of the canadian foothills belt and adjacent foreland has been determined by vitrinite reflectance measurements the present study focusses on two coal bearing sequences bluesky gething and gates formation both of which contain coal resources of economic interest the vitrinite reflectances r max in the bluesky gething formation range from 0 76 high volatile a bituminous to 2 55 semianthracite rank changes from top to the base of bluesky gething formation follow 1st order regression lines factors influencing the rate of increase of r max per depth interval coalification gradient include paleogeothermal gradients the rank level under investigation conductivities of host rocks and thicknesses of coal seams time depth burial curves for the lower cretaceous bluesky gething formation suggest that the regional coalification pattern for the top of the formation results largerly from variations in the depth and or duration of burial beneath maastrichtian tertiary foredeep deposits coalification largerly predates deformation the coalification pattern is more complicated for the base of the bluesky gething formation because thickness changes in the lower cretaceous bluesky gething interval locally have a greater effect on the rank than does the regional change in the thickness of maastrichtian tertiary sedimentary wedge detailed rank studies on laterally continuous coal seams of the gates formation showed that coalification levels were largerly established before folding and thrusting started isoreflectance lines of the beds run parallel to the bedding of the folded strata seams collected from various thrust sheets exposed at surface do not in general show significant changes in vitrinite reflectances from one thrust sheet to another many of the coals of the gates formation were found to have biaxial negative reflectance in dicatrices orientation of r max is in all cases parallel of subparallel to the mactroscopic fold axes indicating preferential orientation of the aromatic lamellae in the coals in the direction of minimum compressive stress it is suggested that the occurrence of biaxial negative coals is related to a tectonic stress field that existed during the later stages of burial and subsequent deformation

thermotectonic history of the southeastern brazilian margin evidence from apatite fission track data of the offshore santos basin and continental basement abstract the santos basin is the largest offshore sedimentary basin in the southeastern brazilian margin and originated by breakup of west gondwana in the early cretaceous we carried out a new thermochronological study by apatite fission track analysis from borehole samples of the santos basin and its continental basement to constrain the tectonic history of the southeastern brazilian margin apatite fission track central ages of the basement and borehole samples vary from 21 0 1 8 to 157 0 35 0 ma and from 6 5 1 1 to 208 0 11 0 ma respectively from thermal modeling the basement samples reached the maximum paleotemperatures during the final breakup of south america and africa the onshore basement and offshore basin record an early thermotectonic event during the late cretaceous linked to the uplift and denudation of the serra do mar and serra da mantiqueira maturation of the organic matter in the offshore basin is related with the progressive increase of the geothermal gradient due to burial the thermal modeling indicates that the oil generation window started at 55 25 ma the basement samples experienced the final cooling during the cenozoic with an estimated amount of denudation linked to the sedimentary influx in the offshore basin a rapid cooling during the neogene becomes evident and it is linked to the reactivation along precambrian shear zones and change of the paraiba do sul drainage system

fire decreases near surface hydraulic conductivity and macropore flow in blanket peat many peatlands have been subjected to wildfire or prescribed burning but it is not known how these fires influence near surface hydrological processes macropores are important flowpaths in the upper layers of blanket peat and were investigated through the use of tension disc infiltrometers which also provide data on saturated hydraulic conductivity measurements were performed on unburnt peat u where prescribed burning had taken place 2years b2 4years b4 and 15 b15 years prior to sampling and where a wildfire w had taken place 4months prior to sampling where there had been recent burning b2 b4 and w saturated hydraulic conductivity was approximately three times lower than where there was no burning u or where burning was last conducted 15years ago b15 similarly the contribution of macropore flow to overall infiltration was significantly lower between 12 and 25 less in the recently burnt treatments compared to b15 and u there were no significant differences in saturated hydraulic conductivity or macropore flow between peat that had been subject to recent wildfire w and those that had undergone recent prescribed burning b2 and b4 the results suggest that fire influences the near surface hydrological functioning of peatlands but that recovery in terms of saturated hydraulic conductivity and macropore flow may be possible within two decades if there are no further fires

frequent fires intensify soil crusting physicochemical feedback in the pedoderm of long term burn experiments in south africa savannas and grasslands in south africa are adapted to fire yet long term effects of fire on soil water and nutrients remain largely unknown to determine whether frequent burning increases the tendency of soils to crust and alters soil chemistry topsoils from 19 sites were examined in mpumalanga kwazulu natal and the eastern cape where annual burning and fire exclusion experiments had been conducted for at least 28 years a comparison of soils from burnt and unburnt plots revealed that composite samples taken to a depth of 10 cm from burnt plots had lower laboratory infiltration electrical conductivity ec of 1 5 extracts water soluble k water soluble nh4 total c total n and labile c burnt plots had higher ph in kcl water dispersible clay and modulus of rupture rate of soil respiration from composite samples 0 2 cm from burnt plots was lower than from unburnt plots means of 21 vs 36 ng c g 1 s 1 rainfall simulation on the same samples demonstrated that burnt plots crusted more rapidly than unburnt plots 19 vs 35 mm h 1 while results from sampling at 1 cm intervals revealed that the greatest differences between burnt and unburnt plots were in the 0 1 cm layer the top few centimetres of soil are likely to have a disproportionate effect on ecosystem functioning by influencing the rate of infiltration and mineralisation of soil organic matter this thin surface layer has been named the pedoderm in this paper soil from 0 1 cm in burnt plots had lower total c means of 0 8 vs 2 7 for burnt and unburnt plots respectively total n 0 07 vs 0 23 nh4 oac extractable ca 7 vs 17 mmolc kg 1 mg 2 vs 7 mmolc kg 1 k 0 8 vs 1 5 mmolc kg 1 and a greater exchangeable na percentage 17 vs 8 the results indicate that burning increases soil crusting this was ascribed to a decrease in humus content and associated disaggregating effect and an increase in the dispersion of clay nutrients are lost from burnt plots over time probably by the removal of ash in surface runoff calcium mg and k were lost more readily than na probably because plants take up these nutrients in greater concentration than na the net effect was an increase in the exchangeable sodium percentage esp crusting on burnt plots may be self perpetuating because increased runoff is likely to increase the loss of soluble salts

tectonics and sedimentation in southern south america during triassic abstract triassic continental sedimentation in southern south america is related to the gondwanides orogenesis directly there were two distinct phases of sedimentation 1 the wide alluvial basins during early triassic and 2 the restricted extensional basins during middle and late triassic the main early triassic deposits are the sanga do cabral supersequence southernmost brazil and uruguay and the talampaya and tarjados sequences western argentina these deposits represent poorly channelized braided rivers with source areas in the gondwanides units under compressional tectonic setting the main middle and late triassic strata are rifts in the back arc setting such as the ischigualasto and cuyo basins western argentina and in the intracontinental setting santa maria supersequence southernmost brazil these basins are mainly composed of alluvial lacustrine and deltaic deposits with a great pyroclastic contribution in the case of the basins of argentina two rift sequences were identified in the western argentina basins composed of syn rift alluvial deposition followed by lake transgression the sag phase is marked by the progradation of deltaic and high sinuosity rivers the southernmost brazil deposits were divided into three rift sequences composed of low sinuosity rivers followed by lake transgression the progradation of deltaic and fluvial systems marks the sag phase the accommodation space generation within the back arc rifts was high if compared to the intracontinental coeval basin due to higher base level and higher tectonic subsidence rates the development of deep organic matter rich lakes suggests a more humid palaeoclimate in the back arc region than in the intracontinental setting where playa lakes dominated the back arc rifts are related to sinistral transtensional stresses in the western branch of gondwanides region the intracontinental rifts the southernmost brazil deposits and coeval rift basins of southern africa were generated by transtensional stresses within a dextral shear zone the shear is related to stress transmission from the southern branch of the gonwanides where oblique compression occurred

numerical simulation of the impact of sediment supply and streamflow variations on channel grain sizes and chinook salmon habitat in mountain drainage networks climatically driven changes in streamflow and hillslope sediment supply could potentially alter stream surface grain size distribution patterns and thereby impact habitat for a number of threatened and endangered in stream fish species relatively little is known about hydrograph shape peak flow influence or the relative importance of chronic and episodic hillslope inputs on channel conditions to better understand these external drivers we calculated sediment routing through a gravel bedded river network using a one dimensional 1d bedload transport model we calculated changes in grain sizes and estimated chinook salmon habitat suitability caused by a dry year and an extreme flood hydrograph and chronic diffusive overland flow or pulse landslide debris flow hillslope sediment supplies to obtain accurate channel conditions a relatively high reference shields stress representative of steep mountain streams was needed an extreme event flood without any hillslope sediment inputs caused widespread bed coarsening and a decrease in aquatic habitat chronic sediment input combined with this hydrograph eliminated any changes in grain size and habitat although when combined with a dry year flow caused systematic bed fining the influence of a given hydrograph therefore highly depends on the hillslope sediment supply regardless of the flow hydrograph or sediment pulse timing grain size distribution or location pulse sediment inputs did not cause widespread grain size changes despite being 100 times the total chronic input volume widespread and continuous hillslope sediment inputs may influence channel grain sizes and aquatic habitat more than a single discrete sediment pulse depending on the magnitudes of flow hydrograph and sediment supply alterations climate change may induce no differences in grain sizes or very dramatic changes with significant consequences for long term sustainability copyright 2013 john wiley sons ltd

the effects of soil texture and ash thickness on the post fire hydrological response from ash covered soils summary ash increases the post fire hydrological response to rainfall in some situations but decreases it in others and the reasons for this variability are not well defined we used simulated rainfall experiments to determine whether the varying hydrological effect of ash can be attributed to differences in the underlying soil texture or the ash thickness we compared the infiltration rates 1 before and after controlled burns in 0 5 m2 plots underlain by two sharply contrasting soil textures sandy loam and gravelly silt loam and 2 before and after the addition of 0 5 2 5 and 5 0 cm of ash to the burned sandy loam plots with the original ash layer removed the controlled burns left a 1 cm ash layer comprised mostly of silt and fine sand particles that clogged the largest pores in the sandy loam soil reducing the final infiltration rate from 91 mm h 1 to 35 mm h 1 but had no effect on infiltration in the silt loam plots pore clogging also reduced the final infiltration rate by 20 mm h 1 40 and the total infiltration by 16 mm 24 when 0 5 cm of ash was added to the sandy loam plots however increased storage in the ash layer combined with slight increases in the final infiltration rate by 5 and 18 mm h 1 respectively increased the total infiltration by 16 mm 30 and 18 mm 26 respectively with the thicker ash addition treatments thus the varying effect of ash on infiltration and runoff can be at least partially attributed to between site differences in soil texture and ash thickness a thin ash layer

infiltration runoff and soil loss in andisols affected by forest fire canary islands spain depending on the severity of the fire forest fires may modify infiltration and soil erosion processes rainfall simulations were used to determine the hydrological effects of fire on andisols in a pine forest burned by a wildfire in 2007 six burned zones with different fire severities were compared with unburned zones infiltration runoff and soil loss were analysed on slopes of 10 and 30 forest floor and soil properties were evaluated unburned zones exhibited relatively low infiltration 23 and 16 mm h 1 on 10 and 30 slope angles respectively and high average runoff rainfall ratios 43 and 50 on 10 and 30 slope angles respectively which were associated with the extreme water repellency of the forest floor nonetheless this layer seems to provide protection against raindrop impact and soil losses were found to be low 8 and 16 g m 2 h 1 for 10 and 30 slope angles respectively soil cover soil structure and water repellency were the main properties affected by the fire the fire reduced forest floor and soil repellency allowing rapid infiltration moreover a significant decrease was noted in soil aggregate stabilities in the burned zones which limited the infiltration rates consequently no significant differences in infiltration and runoff were found between the burned and the unburned zones the decrease in post fire soil cover and soil stability resulted in order of magnitude increases in erosion sediment rates were 15 and 31 g m 2 h 1 on the 10 and 30 slope angles respectively in zones affected by light fire severity in the moderate fire severity zones these values reached 65 and 260 g m 2 h 1 for the 10 and 30 slope angles respectively copyright 2012 john wiley sons ltd

tar sandstones in the parana basin of brazil structural and magmatic controls of hydrocarbon charge abstract there are tar accumulations in lower triassic sandstones along the eastern margin of the parana basin the tar was derived from permian source rocks that matured along the basic sills of the serra geral continental flood basalt cover this paper exams the habitat of tar accumulation integrating fieldwork with morphostructural data digital elevation modelling gravity and airborne magnetic data remote sensing and radiometric dates that constrain the timing of maturation and migration the focus of this work is the jacu structural complex a large annular drainage anomaly 20 km in diameter that owes its origin to reactivation of pre existing faults interpretation of the structural framework is based primarily on morphostructural analysis and the distribution of gravity anomalies the jacu structure consists of a central low lying fault block that is surrounded by several structural highs and is attributed to the interaction of ne and nw striking fault zones the principal basement faults that encapsulate this structure were invaded by the dolerite dykes that fed the widespread flood basalt cover during the early cretaceous an 40 ar 39 ar analysis directly dates this episode of magmatism to 134 2 ma tar sandstones are restricted to the lower piramboia formation and are present around the jacu structure especially near the structural highs or close to basic dikes morphostructural interpretation suggests the occurrence of tar sandstones at intermediate positions too between the structural highs and lows the most likely explanation for these tar accumulations relates oil maturation and migration to the intrusion of lower cretaceous serra geral sills into the upper permian black shales of the irati formation and subsequent migration along faults and dyke walls into eolian sandstone reservoirs of the triassic piramboia formation not only did the basic dykes locally facilitate migration but there were also places where they were barriers to lateral migration furthermore the interdune and fluvial facies of the piramboia formation formed local seals and barriers to vertical migration

soil hydrophobicity effects on rainsplash simulated rainfall and photographic evidence laboratory rainfall simulation experiments indicate greater splash losses for hydrophobic water repellent than for wettable sandy loam soils at different rainfall intensities durations and soil surface inclinations using synchronized video cameras with different shutter speeds and stroboscopically illuminated 35 mm still photography differences in splash droplets and ejection trajectory characteristics are examined for hydrophobic soil raindrop impact gives rise to fewer larger slower moving daughter ejection droplets which carry more sediment and hence follow shorter range trajectories compared with wettable soil implications for erosion of hydrophobic soils are discussed

coalbed methane characteristics of gates formation coals northeastern british columbia effect of maceral composition the majority of research reported on methane adsorption characteristics of coal seams has focused on vitrinite rich coals however western canadian coals are more inertinite rich than those of the western united states and are shown to differ in gas adsorption characteristics the influence of maceral composition upon gas adsorption characteristics of medium volatile coal samples from the middle cretaceous gates formation of northeastern british columbia was investigated lithotype coal facies samples were analyzed for surface area maceral and mineral composition and methane adsorption standard coal analyses were also performed proximate low temperature ash and equilibrium moisture the vitrinite content of the samples analyzed ranges from 18 to 95 vol min ral matter free the ash yield varies from 4 4 to 33 7 wt both maceral composition and mineral matter content have an important influence on adsorption characteristics as indicated by carbon dioxide surface areas and methane adsorption isotherms on a mineral matter free basis the amount of methane adsorbed generally increases with vitrinite enrichment the lowest methane adsorption occurs in the sample with the highest inertinite content carbon dioxide surface areas of the lithotypes range from 87 to 176 m2 g on a raw coal basis and from 99 to 184 m2 g on a mineral matter free basis surface area generally decreases with increased mineral matter content and increases with increased vitrinite content the increase in adsorption of both methane and carbon dioxide with increased vitrinite concentration is interpreted a resulting from differences in the pore size distribution of vitrinite and inertinite vitrinite is predominantly microporous whereas inertinite is meso to macroporous the monolayer volumes of carbon dioxide as calculated from the dubininradushkevich equation are higher than those of methane as determined from the langmuir equation but are correlated the methane adsorption isotherms and surface area data indicate that the maceral compositional variations in coal are at least as significant as coal rank in determining the potential volume of adsorbed methane and thus the coalbed methane potential of a deposit

holocene palaeofire records in a high level proximal valley fill wilson bog mount lofty ranges south australia an elevated valley fill peat bog wilson bog near mount lofty south australia failed in november 2005 following a flooding event and exposed representative sections of the sediment infill two

age constraints of the glaciation in the parana basin evidence from new u pb dates the absence of absolute dating in glacial deposits of the parana basin prevents better understanding of the complete history of the late palaeozoic ice age in western gondwana and the climatic change that took place in the late carboniferous in this study new u pb radiometric ages date the topmost glacial deposits of the itarare group at 307 7 3 1 ma kasimovian moscovian and the base of post glacial deposits of the rio bonito formation at 298 8 1 9 ma ghzelian asselian correlation of glacial and post glacial deposits of the parana basin with other southwestern gondwana basins shows that the end of the late palaeozoic ice age is asynchronous supplementary material laser ablation inductively coupled plasma mass spectrometry u pb zircon data and methods for the ash sample of the itarare group and the tonstein sample of the rio bonito formation are available at https doi org 10 6084 m9 figshare c 3278273

effect of water saturation and temperature in the range of 193 to 373 k on the thermal conductivity of sandstone abstract the thermal conductivity of porous media is crucial for many geological and engineering projects although the thermal conductivity at low temperatures is often overlooked it is of great significance to calculate the amount of heat that the ice sheet absorbs from the earth in this study the thermal conductivity of dry and water saturated sandstone was measured in the temperature range of 193 to 373 k using a transient hot wire method all samples were collected from east china with a sample porosity distribution of 5 to 13 the effects of temperature water saturation and phase transition of fluid in the pores were investigated the results indicate that the thermal conductivity decreases with an increase in temperature and that the decrease is steeper when the temperature is below 273 k moreover it is found that the thermal conductivity of the saturated sandstone is larger than that of the dry sandstone with an increase in porosity the thermal conductivity significantly increases in saturated sandstone but remains almost the same or even decreases in dry sandstones finally it is revealed that the effect of phase transformation on the thermal conductivity is significant when the water in pores becomes ice the thermal conductivity increases significantly and increases further as the temperature decreases

a process for fire related debris flow initiation cerro grande fire new mexico in this study we examine factors that pertain to the generation of debris flows from a basin recently burned by wildfire throughout the summer 2000 thunderstorm season we monitored rain gauges channel cross sections hillslope transects and nine sediment runoff traps deployed in a steep 0 15 km 2 basin burned by the may 2000 cerro grande fire in new mexico debris flows were triggered in the monitored basin during a rainstorm on july 16 2000 in response to a maximum 30 min rainfall intensity of 31 mm h 1 return period of approximately 2 years eleven other storms occurred before and after the july storm these storms resulted in significant runoff but did not generate debris flows the debris flows generated by the july 16 storm initiated on a broad open hillslope as levee lined rills the levees were composed of gravel and cobble sized material supported by an abundant fine grained matrix debris flow deposits were observed only on the hillslopes and in the first and second order drainages of the monitored basin no significant amounts of channel incision were measured following the passage of the debris flows indicating that most of the material in the flows originated from the hillslopes sediment runoff concentrations of between 0 23 and 0 81 kg l 1 with a mean of 0 42 kg l 1 were measured from the hillslope traps following the debris flow producing storm these concentrations however were not unique to the july 16 storm the materials entrained by the july 16 storm contained a higher proportion of silt plus clay sized materials in the 2 mm fraction than the materials collected from storms that produced comparable sediment runoff concentrations but not debris flows the difference in materials demonstrates the critical role of the availability of fine grained wood ash mantling the hillslopes in the runoff dominated generation of post wildfire debris flows the highest sediment runoff concentrations again not unique to debris flow production were produced from maximum 30 min rainfall intensities greater than 20 mm h 1

u pb dating of tonstein layers from a coal succession of the southern parana basin brazil a new geochronological approach abstract this paper presents new radiometric dating of zircons idtims u pb from tonsteins interbedded with coal seams from the candiota coalfield rio grande do sul state the ages obtained 296 9 1 65 ma and 296 4 2 ma are consistent within error and are quite different from a previously published age of 267 1 3 4 ma calibrations of palynostratigraphic data with numerical ages showed that the candiota coals from the southern parana basin related to the protohaploxypinus goraiensis subzone are constrained to the asselian consequently the basal part of the gondwana sequence in the southern part of the basin must belong to the carboniferous permian boundary and not to the sakmarian as it was previously considered the new results have far reaching significance for correlations of the parana basin with sequences of the argentinian paganzo basin 302 6 ma and 288 7 ma and also with the karoo basin with the top of the dwyka tillite 302 3 ma and 299 2 3 2 ma and with the lowermost ecca group 288 3 ma and 289 6 3 8 ma this new evidence supports the presence of an active and widespread upper carboniferous volcanism in western gondwana

a petrological and organic geochemical study of permian coal seams east of maracaja south santa catarina parana basin brazil abstract coal samples from the permian rio bonito formation collected from borehole mml 09 east of maracaja south santa catarina parana basin brazil were characterized by petrological vitrinite reflectance measurements maceral analyses and geochemical rock eval total organic carbon toc and gc ms methods the mean vitrinite reflectance values range from 0 73 to 0 87 rrandom indicating a rank level of high volatile b a bituminous the maceral composition showed predominance of vitrinite 49 4 to 61 2 vol and inertinite 9 to 24 5 vol the rock eval analysis presented the following values s1 and s2 ranging from 0 74 to 2 51 mg hc g coal and 34 1 to 108 87 mg hc g coal respectively hydrogen indices between 158 and 240 mg hc g toc and tmax c between 440 and 448 c the toc contents of the coal samples present values ranging from 18 85 to 45 31 wt vitrinite reflectance and rock eval tmax values indicate that the coals are in the beginning of the oil generation window the potential for the formation of liquid hydrocarbons is rather low due to the nature of the humic coal whereas the rank level indicates that generation of gas from the coal has occurred the biomarker analysis using gc ms and gc ms ms allowed the interpretation of the depositional environment and provided another way of determining the degree of maturity of the coals besides vitrinite reflectance and tmax the pristane phytane pr ph ratio is 1 mainly controlled by organic matter type implied suboxic conditions during sedimentation the vitrinite reflectance measurements tmax values and 20s 20s 20r and ratios for c29 regular steranes revealed the marginally mature stage of the organic matter although the distribution of hopanes indicated a mature stage of the organic matter due to the absence of hopanes and predominance of the 22s epimer over the 22r epimer for the hopanes from c 31 to c 35

the hydrological properties and the effects of hydration on vegetative ash from the northern rockies usa abstract vegetative ash is known to alter post fire runoff rates in some cases decreasing runoff by protecting the underlying soil and in other cases aiding in the formation of a surface seal increasing runoff variability in this hydrological response of ash may reflect differences in the hydrologic properties of ash caused by shifts in its physical and chemical characteristics this study investigated the physical particle size and shape particle density bulk density and porosity chemical mineralogy and elemental composition and hydrologic water retention hydraulic conductivity and sorptivity characteristics of laboratory and wildfire ash from the northern rocky mountain region of the united states a variety of techniques were used including scanning electron microscope x ray diffraction thermogravimetric analysis and conventional soil science techniques laboratory ash samples were prepared by combusting fuel from three dominant trees species of the region pinus contorta pinus ponderosa and pseudotsuga menziesii at various combustion temperatures 300 c 500 c 700 c or 900 c the main objectives of this study were to determine i how the physical particle size and shape particle density bulk density and porosity and chemical mineralogy and elemental composition properties of ash might explain variations in hydrologic properties water retention hydraulic conductivity and sorptivity ii whether wetting alters the physical chemical and hydrologic properties of ash iii whether ash characteristics could be linked to various stages of thermal decomposition and whether ash produced in the laboratory could be beneficial to understanding wildfire ash characteristics and iv whether ash hydrologic properties can be linked to simple metrics such as calcium carbonate content or color which can be used in rapid post fire hazard assessment results of this study indicate that variation in the hydrological response of ash can be partially explained by differences in ash characteristics associated with combustion temperature depending on ash mineralogy which was dictated by the level of thermal decomposition of organic material ash particles can a contain micro porosity contributing to total porosity values as high as 98 b shift hydraulic conductivity values orders of magnitude from 0 12 0 03 to 0 002 0 0003 cm s 1 and c chemically transform after initial hydration suggesting that ash layers could alter post fire runoff response by creating a chemical crust furthermore while ash color is often used as an indicator of burn severity it may not be an accurate indicator regarding the hydrologic response of ash in post fire systems instead carbonate content is suggested as a more informative aid in predicting post fire hydrologic response

the lower and upper coal seams of the candiota coalfield brazil geological setting petrological and chemical characterization and studies on reactivity and beneficiation related to their combustion potential abstract in the candiota coalfield rs brazil the candiota superior and inferior coal seams are at current time being mined for power generation the current study characterizes the other seams of the deposit which include the upper s2 s9 seams the banco louco bl seam and the lower i1 i5 seams which up to date have not been considered for power generation the analytical techniques applied in this study include sequence stratigraphic analysis of the coal bearing interval petrographical and chemical analyses of the coal seams reactivity tests based on thermobalance experiments and studies on beneficiation sequence stratigraphic analyses sedimentological analyses identified four depositional systems in the study area alluvial fan fluvial lagoon barrier and shallow marine with coal seams developed in transgressive systems tract highstand systems tract and lowstand systems tract petrographical and chemical analyses the petrographical analyses showed that the most abundant maceral in the coals is vitrinite followed by inertinite and liptinite the average vitrinite reflectance is indicative of subbituminous rank 0 41 rr the values for ash yield range from 29 0 to 74 2 wt average 49 1 wt and for volatile matter contents vary from 13 5 to 29 5 wt average 19 9 wt sulfur contents range from 0 4 to 8 1 wt average 1 9 wt the gross calorific values as received basis range from 841 to 3727 cal g average 2632 cal g based on x ray diffraction analysis the most abundant minerals in the coal seams are quartz kaolinite illite and k feldspar reactivity studies thermogravimetric analyses carried out on fourteen seam channel samples showed differences in the combustion behavior of the seams in particular for the inertinite rich seams s8 and banco louco the i2 seam analyzed from four of the eight exploration wells indicated very similar combustion properties based on the thermogravimetric analyses beneficiation tests from the sink float tests and proximate and ultimate analyses washability curves were prepared for all upper lower and bl seams 20 cm thick these curves were plotted showing ash distribution and total sulfur content for a grain size between 25 4 mm and 2 0 mm fraction a 25 4 2 0 mm and for a grain size between 2 0 mm and 0 1 mm fraction b 2 0 0 1 mm these curves provided important information to a possible gravimetric beneficiation for both size fractions however the performance of such beneficiation mainly depends on both the near gravity material ngm value and separation density of each seam which are the main parameters analyzed in addition these curves showed low values of total sulfur content in any separation density however the densest fractions were not taken into consideration conclusion the results of the chemical and petrological analyses as well as the studies on combustion and beneficiation characteristics suggest that the seams investigated in this study s1 s9 bl i1 i5 do have the potential for being used in power generation

radiometric age determination of tonsteins and stratigraphic constraints for the lower permian coal succession in southern parana basin brazil abstract ion microprobe shrimp ii dating of zircons from tonsteins interbedded with coal seams from the candiota and faxinal coalfields early permian rio bonito formation parana basin brazil is presented the mean ages obtained 290 6 1 5 ma are more precise than previously published intervals calibrations of chronostratigraphic data with radiometric ages show that the main coal succession from the southern basin is constrained to the middle sakmarian the 2 ma time interval of deposition supports the hypothesis that the coal generating process was quite rapid in terms of geological time in a general context faxinal and candiota coals are assigned into the protohaploxypinus goraiensis subzone besides some paleocological differences evidenced by palynological studies this bio interval does not correspond to a consistent palynostratigraphic tool and more accurate biostratigraphic zonation for the carboniferous permian interval must be delineated the new results have far reaching significance for correlations of the basin with sequences of the argentinian paganzo basin 302 6 ma and 288 7 ma and also with the karoo basin with the lowermost ecca group 288 3 ma and 289 6 3 8 ma this new evidence supports the presence of an active and widespread lower permian explosive volcanic event in western gondwana which is interpreted as the same volcanism which produced the choiyoi group in western argentina according to this correlation the ash fall source is located about 1400 km to the southwest of their area of deposition

depositional setting petrology and chemistry of permian coals from the parana basin 2 south santa catarina coalfield brazil abstract in brazil economically important coal deposits occur in the southern part of the parana basin where coal seams occur in the permian rio bonito formation with major coal development in the states of rio grande de sul and santa catarina the current paper presents results on sequence stratigraphic interpretation of the coal bearing strata and petrological and geochemical coal seam characterization from the south santa catarina coalfield parana basin in terms of sequence stratigraphic interpretation the precursor mires of the santa catarina coal seams formed in an estuarine barrier shoreface depositional environment with major peat accumulation in a high stand systems tract pre bonito and bonito seams a lowstand systems tract ponta alta seam seam a seam b and a transgressive systems tract irapua barro branco and treviso seams seam thicknesses range from 1 70 to 2 39 m but high proportions of impure coal coaly shale and shaley coal carbonaceous shale and partings reduce the net coal thickness significantly coal lithoypes are variable with banded coal predominant in the barro branco seam and banded dull and dull coal predominantly in bonito and irapua seams respectively results from petrographic analyses indicate a vitrinite reflectance range from 0 76 to 1 63 rrandom hvb a to lvb coal maceral group distribution varies significantly with the barro branco seam having the highest vitrinite content mean 67 5 vol whereas the irapua seam has the highest inertinite content 33 8 vol liptinite mean values range from 7 8 vol barro branco seam to 22 5 vol irapua seam results from proximate analyses indicate for the three seams high ash yields 50 2 64 2 wt considering the international classification of in seam coals all samples are in fact classified as carbonaceous rocks 50 wt ash sulfur contents range from 3 4 to 7 7 wt of which the major part occurs as pyritic sulfur results of x ray diffraction indicate the predominance of quartz and kaolinite also pyrite gypsum gibbsite jarosite and calcite were also identified in some samples feldspar was noted but is rare the major element distribution in the three seams coal basis is dominated by sio 2 31 3 wt mean value al 2 o 3 14 5 wt mean value and fe 2 o 3 6 9 wt mean value considering the concentrations of trace elements that are of potential environmental hazards the barro branco bonito and irapua seams coal base are significantly enriched in co 15 7 ppm cr 54 5 ppm li 59 3 ppm mn 150 4 ppm pb 58 0 ppm and v 99 6 ppm when compared to average trace elements contents reported for u s coals hierarchical cluster analysis identified based on similarity levels three groups of major elements and seven groups of trace elements applying discriminant analyses using trace and major element distribution it could be demonstrated that the three seams from santa catarina show distinct populations in the discriminant analyses plots and also differ from the coals of rio grande do sul analyzed in a previous study

runoff and erosion processes after a forest fire in mount carmel a mediterranean area in the mediterranean forest area of israel fires increase runoff and sediment yield rates relative to undisturbed forested land the september 1989 fire covered an area of 4 km2 in the main recreation area of mount carmel a typical mediterranean forest area the lithology is chalk and limestone and about 40 of the burnt area has steep slopes exceeding 30 three study plots were established in burnt and unburnt areas plots were located on 100 300 m2 areas with different slope exposures runoff and sediments were collected after each storm by a collector system a hydrometric station was established draining an area of 1 km2 in the burnt zone rainfall was measured by two recorders and several rain gauges at the experimental sites in the first rainfall season after the fire runoff and sediment yield were 500 and 100 000 times higher respectively in the burnt areas rainfall intensity is a dominant factor in runoff and sediment yield rates in the measured basin total runoff in the first year was 1 6 revegetation recovery of the area was rapid as shown by the results from the second season runoff decreased by one order of magnitude from an average of 10 mm to 1 5 mm sediment yield decreased by two orders of magnitude from 1200 g m 2 to 10 g m 2 the third season 1991 1992 was an exceptionally rainy year and therefore runoff and sediment yield increased but to less than in the first year runoff and sediment yield are related to vegetation cover rainfall intensity soil properties slope steepness and exposure and fire intensity logging activities after fire increase sediment yields through its effects on vegetation cover and soil fire severity increases the potential for erosion

shrimp u pb zircon dating and palynology of bentonitic layers from the permian irati formation parana basin brazil abstract this paper presents the first shrimp zircon age data from bentonitic ash fall layers intercalated with the irati sedimentary rocks as well as palynofossils retrieved from the petrobras six mine parana state southern brazil the permian irati formation is one the most important oil source horizons within the parana basin and consists mainly of siltstones gray claystones as well as organic rich claystones intercalated with limestones zircon morphology based on cathodoluminescence images includes two different populations a dominant population of euhedral prismatic elongate to acicular grains which are most likely related to an ash fall volcanism and a population of rounded to large prismatic grains that were interpreted as detrital grains shrimp analysis performed on the euhedral and prismatic grains revealed an age of ca 278 4 2 2 ma 7 points with 95 confidence interpreted as the crystallization age of the volcanic eruption based on this new dating the irati formation should be placed on the lower permian cisuralian artinskian in age modifying substantially the traditional ages previously attributed to this unit the palynofossils from this level include key species of the lueckisporites virkkiae zone such as l virkkiae l densicorpus l stenotaeniatus weylandites lucifer alisporites splendens typical species of this zone also occur in african and other south american argentina permian strata allowing stratigraphical correlations the origin of the ash falls is not clearly defined it may be related either to calc alkaline arc magmatism associated to the sanrafaelica orogeny 275 and 250 ma or to bimodal volcanic events associated to an early intracontinental rift developed within southwestern gondwana at ca 278 my the dating of this unit is significative to calibrate biostratigraphic schemes along the parana basin as well as equivalent zones in gondwana areas mainly in its occidental portion