early diagenetic transformation of higher plant triterpenoids in deep sea sediments from baffin bay abstract a sediment sequence of early miocene to holocene from ocean drilling program site 645 in central baffin bay was found to contain abundant triterpenoids of higher plant origin including monodesmethyl derivatives and other oxidative degradation products 24 nor triterpenoids of the oleanene ursene and lupane series were found in the nonaromatic hydrocarbon and alcohol fractions of the sediment extracts other diagenetic transformation products included 24 28 dinor olean 17 ene and 24 nor urs 12 en 1 1 one as well as their tentatively identified des a counterparts the identification of these novel degradation products was confirmed by synthesis of a suite of reference compounds the simple reaction sequence applied to obtain 24 nor urs 12 ene from 3 acetoxyurs 12 en 24 oic acid is likely to happen in a similar manner during early diagenesis of organic matter in nature these results have implications for the understanding of the diagenetic reaction sequence leading to the formation of other demethylated triterpenoids of terrigenous origin e g 24 28 dinor lupanes 28 30 dinor 17 hopane is sometimes the dominant hydrocarbon in the most deeply buried samples its co occurrence with higher plant triterpenoids and the low abundance of other regular hopanoids is not considered an indication however that 28 30 dinor 17 hopane is derived from a higher plant precursor molecule it is suggested that two independent sedimentary processes are responsible for the presence of the two types of demethylated triterpenoids observed in baffin bay sediments

early diagenesis of terrigenous triterpenoids and its implications for petroleum geochemistry abstract the distribution of triterpanes in sediments and crude oils is commonly used for oil oil and oil source rock correlation in petroleum geochemistry while isomer ratios of such compounds are applied as maturity parameters the triterpane pattern in terrestrially influenced geological samples is however remarkably less diverse than the triterpenoid skeletons occurring in the extant higher plant biosphere natural observations laboratory experiments and molecular mechanics calculations have revealed that acid catalysed double bond isomerization and skeletal rearrangement reactions of terrigenous triterpenoids during early diagenesis are the key to understanding the triterpane patterns in more matured geological materials examples studied in detail are the double bond isomerization of oleanenes and the subsequent hydrogenation of the products into oleanane and 18 oleanane and the transformation of taraxer 14 ene and lup 20 29 ene into oleanenes although the reactions are likely to be kinetically controlled the main products formed and ultimately preserved are the thermodynamically most stable ones the experimental results and natural observations have significant implications for the use of terrigenous triterpenoid compounds in petroleum geochemistry

stable isotope geochemistry of crude oils and of possible source rocks from new zealand 2 sulfur abstract the sulfur isotopic composition of new zealand low s crude oils and components asphaltenes absorptive filtration fractions and source rock components extracted hydrocarbons kerogen pyrite sulfates were determined oils from the taranaki basin have 34s values from 3 to 14 o the lower values possibly represent plant assimilation of fresh water sulphate higher values particularly those from the west coast basin around 20 suggest closed ocean basin conditions or fast sedimentation rate whereas negative 34s values from east coast basin suggest open ocean or low sedimentation rate conditions it is suggested than an oil source rock relation should show as a similarity in 34s values for total oil and source rock extract kerogen and pyrite shale samples analysed plot outside the corresponding oil range and cannot be considered as possible source rocks however coal samples from the maui 4 well and nelson outcrops show strong isotopic correlations with the taranaki oils

bicadinanes and related compounds as maturity indicators for oils and sediments abstract biomarker maturity indices have proven useful in petroleum exploration to assess the thermal maturity of oils and sediments however their application to deltaic petroleum systems is often hindered by source and diagenetic interferences recently we have described several new maturity indices based on the catagenetic products of the plant biopolymer polycadinene these indices should be largely immune to biochemical effects during diagenesis since little microbial activity will remain at temperatures sufficient to dissociate the polymer here we report changes in five polycadinene related maturity indices through a marine fluvio deltaic depositional sequence in the south sumatra basin indonesia the results are compared with the maturity required for oil generation as estimated by kinetic modelling and with conventional maturity indicators such as sterane epimerisation and the methyl phenanthrene index the data confirm that the polycadinene indices are less subject to source and diagenetic interferences than those based on the sterane and aromatic hydrocarbon distributions values for several of the indices have also been measured for 17 tertiary oils from southeast asia papua new guinea new zealand and australia contrary to an earlier report the bicadinane maturity indicator bmi 1 continues to change into the oil window and hence may be useful in ranking the relative maturity of oils as well as sediments the bmi 1 values for two oils having unusually low sterane maturities are normal leading us to question whether the low sterane maturity of many tertiary age oils is due to their source rocks having been heated more rapidly than those of older oils

natural attenuation of arsenic in the tinto santa rosa acid stream iberian pyritic belt sw spain the role of iron precipitates acid waters and sediments of the tinto santa rosa acid stream iberian pyritic belt sw spain were analysed to determine the role of sedimentary phases in the behaviour of arsenic aqueous arsenic and iron concentrations decreased markedly from the adit mouth to 300 m downstream indicating iron minerals precipitation as well as arsenic sorption onto these newly formed phases this was confirmed by the high arsenic concentrations observed in bed stream precipitates which play a major role in controlling arsenic mobility to unravel the complex nature of the amd sediments a combination of techniques including x ray diffraction xrd scanning electron microscopy sem total solid digestions x ray fluorescence xrf and x ray absorption spectroscopy xas were employed results showed that 1 arsenic was present predominantly in its pentavalent state 2 upstream arsenic was sorbed onto the main phase schwertmannite whereas downstream it was chiefly associated with goethite and jarosite and 3 changes in arsenic speciation with depth were observed in the consolidated terrace sediments where arsenic appeared primarily associated with schwertmannite in the upper part of the terraces but with goethite at depth arsenic mobilization was controlled by sorption onto newly formed precipitates schwertmannite goethite and jarosite causing natural arsenic attenuation

origin of perylene in ancient sediments and its geological significance the distributions of polycyclic aromatic hydrocarbons pahs in sediments of three upper triassic to middle jurassic sedimentary sequences from the northern carnarvon basin australia have been investigated perylene was found to be a major pah component in the top lower to base middle jurassic sediments that are immature or at low maturity its depth age profiles are not related to the combustion derived pahs that have been believed to be produced during ancient vegetation fires before deposition this suggests a diagenetic origin for perylene the concentration of perylene in the sediments is proportional to the amount of terrestrial input decreasing with distance from the source of land sediments its carbon isotope composition is slightly heavier than higher plant derived pahs but still in the range of the terrestrially sourced pahs including higher plant pahs and combustion derived pahs as suggested previously fungi are proposed to be the major precursor carriers for perylene in sediments based on the facts that 1 perylenequinone structures have been previously suggested to be the natural precursors for perylene 2 perylenequinone pigments exist in many fungal bodies 3 fungi have played an important role during geological processes

hydrocarbon potential and depositional environment of the lower cretaceous black mudstones and shales in the coastal guangdong province china abstract the mesozoic especially the cretaceous sequences in the northern south china sea scs are important potential targets of oil and gas exploration however they are currently poorly understood we use organic petrology and geochemistry to evaluate the hydrocarbon potential and study depositional environment of the cretaceous black mudstones and shales from the dayawan section in the guangdong province china these mudstones and shales yield total organic carbon toc contents of 0 63 2 76 and most samples meet the requirement for higher toc source rocks organic matters in the mudstones and shales were sourced mainly from higher plants as well as subordinate benthic macroalgae organic petrology and geochemical data suggested that the organic matters were dominated by type iii and minor type ii and generally have low thermal maturity thus we evaluated the black mudstones and shales have a potential for hydrocarbon generation especially gas prone pr ph trace elements and mixture source of organic matter suggested that these black mudstones and shales formed in a coastal lacustrine environment characterized by weakly oxidizing weakly reducing conditions and low salinity a marine transgression developing in the middle part of the section was recognized generally the northern scs which exhibits the more marine influence likely contains source rocks with higher toc contents and better organic matter types the cretaceous source rocks with higher liquid hydrocarbon generation potential may occur locally in the pearl river mouth basin

alkyldibenzofurans in terrestrial rocks influence of organic facies and maturation abstract dibenzofuran dbf dibenzothiophene dbt and phenanthrene phe have been determined along with their methyl derivatives mdbfs mdbts mps in coals carbonaceous shales and mudstones of lower cretaceous to upper carboniferous ages from the elmworth gas field canada and from the sakoa madagascar and ruhr coal germany basins the samples contained mainly terrestrial organic matter with thermal maturities in the 0 7 1 9 mean vitrinite reflectance rr range the pronounced predominance of mdbfs over mdbts in the sakoa samples is typical of plant debris deposited in lacustrine swamp environments onset of intense mdbf generation occurs at fairly low rank 0 77 rr as indicated by elevated concentrations of 50 120 g mdbfs g total organic carbon toc influences of lithology organic matter type and maturity on distributions of the target compounds were extracted from the molecular concentration data by multivariate statistical methods such as principal components analysis pca and fuzzy c means cluster analysis with nonlinear mapping nlm a specific source effect on 1 mdbt concentrations suggests that lichens contributed to the senescent coal forming forest in the sakoa coal basin alkyldibenzofurans hence are potential lichen biomarkers mdbfs can be used as maturity indicators only beyond 1 0 rr where ruhr coals displayed a distinct increase in the 1 4 mdbf ratio

the western desert versus nile delta a comparative molecular biomarker study abstract the western desert and the nile delta are prolific petroleum producing basins the correlation and matching between their petroleum systems have been briefly studied overall geochemical and biological marker analyses of twelve crude oil and condensate samples taken from seven oil gasfields located in the nile delta and the western desert basins of egypt were effective in identifying and geographically defining two major oil families related by age and source rock depositional environment these samples were classified respectively as late cretaceous tertiary and jurassic early cretaceous the source rocks giving rise to the late cretaceous tertiary oils are associated with abundant terrestrial organic matter the source rocks giving rise to jurassic early cretaceous oil are presumably generated from a mixed terrestrial marine source meanwhile the western desert oil samples show prominent c 30 steranes elevated c 27 monoaromatic steroids and a distinct homohopane distribution suggesting this oil type is derived from a more marine influenced source rock than terrigenous sourced oil in the nile delta the most crucial geochemical fingerprinting biomarkers that have been used to differentiate between nile delta and the western desert oil are oleananes highly branched isoprenoids hbi sterane isomerization 24 norcholestanes aromatic steroid hydrocarbons and c 30 24 n propylcholestanes

the oleananes origin maturation and limits of occurence in southern nigeria sedimentary basins oleananes occur within well defined age and paleogeographic boundaries in the sedimentary province of southern nigeria thus signifying that the biomarkers may be analogous to index fossils in anambra syncline lower benue trough the biomarkers are found in rocks which are as old as late upper cretaceous in tertiary niger delta the concentration composition and distribution of the oleananes in rocks and oils are determined mainly by palaeodepositional environment and thermal history and are independent of age and geographical location of specific samples oleanane content varies with increasing burial depth with peak concentration coinciding within rm range 0 4 0 6 implying early generation of hydrocarbons from the basin s typically resin rich kerogens it is evident that the oleanane content parameter is superior to the hopane and sterane isomerisation indices for monitoring thermal maturation in the delta and for differentiating paralic from paralic marine source facies as well as early from late generated oils

a geochemical characterization of cold water natural acid rock drainage at the zn pb xy deposit yukon canada abstract acid rock drainage ard is considered to be temperature limited due to the diminished activity of fe ii oxidizing microbes at low temperatures nonetheless ard streams are present in cold climates this study presents a geochemical characterization of a cold climate ard creek at the zn pb xy deposit in yukon canada which showed highly elevated concentrations of dissolved zinc up to 475 mg l acid rock drainage at the xy deposit is likely generated via subsurface abiotic and biotic oxidation of sulfide minerals and then exits as seeps at the headwaters of the creek the uppermost reaches of the creek have the lowest ph levels ph 3 3 and highest metal concentrations with prolific precipitation of iron hydroxysulfate and oxyhydroxide mineral precipitates schwertmannite jarosite and goethite present as terraced iron formations tifs at one sampling location the lower reaches of the creek show a progressive ph increase up to ph level 4 9 which occurs due to fe iii and al hydrolysis the neutralizing influence of carbonate rich strata and or ground waters and dilution by surface waters entering the creek progressive ph neutralization causes a change in precipitate mineralogy to x ray amorphous al hydroxysulfates with a composition similar to aluminite and hydrobasaluminite and amorphous al oh 3 natural attenuation of cd zn and pb occurred downstream from the headwater seeps which was likely influenced by adsorption reactions involving both metal sulfate anions and metal sulfate ternary complexes generally the concentrations of cd zn and pb in the mineral precipitates followed trends in ph aqueous concentration predicted speciation and mineralogy of the precipitates however anomalous trace metal concentrations were observed in the precipitates at 120 m downstream and potentially reflect a local ground water input overall the geochemistry of this cold climate ard creek was similar to ard in more temperate climates although low temperatures appear to retard the kinetics of ferrous iron oxidation and seasonal hydrodynamics may influence the formation of tifs in these highly saturated waters

biological markers and carbon isotope composition of organic matter in the upper cretaceous coals and carbonaceous shale succession jiza qamar basin yemen origin type and preservation abstract bituminous coals and carbonaceous shales located in the jiza qamar basin on the eastern yemen were analysed based on a combined investigation of organic geochemistry and petrology to define the palaeodepositional environment condition organic matter inputs and their thermal maturity carbon isotope compositions and various biomarkers were performed on coals and carbonaceous shales within the upper cretaceous mukalla formation in the jiza qamar basin the 13 c values range from 29 2 to 24 5 with average values around 26 7 whereas the organic carbon contents in most sediment samples are consistently high 3 indicating that the organic matter in the mukalla coal and carbonaceous shale sediments has a predominantly terrigenous origin with slightly marine influence during burial this has also been identified from kerogen microscopy which is characterized by dominance of vitrinite and liptinite organic matter the investigated biomarkers indicated that the mukalla coals and carbonaceous shales contain high contribution of land plants with a minor aquatic organic matter input that was deposited in a fluvial to deltaic environments and preserved under relatively oxic conditions this has been achieved from acyclic isoprenoids terpane and sterane biomarkers of a saturated hydrocarbon and dibenzothiophene alkylnaphthalene and methylphenanthrene biomarkers of an aromatic hydrocarbon based on the analysed biomarker thermal maturity indicators it may be deduced that the mukalla coals and carbonaceous shales in the jiza qamar basin have entered an early mature to mature stages for hydrocarbon generation this is also supported by vitrinite reflectance values of 0 63 0 83 ro indicative that these sediments have reached oil window maturity

δ2 triterpenes early intermediates in the diagenesis of terrigenous triterpenoids a series of 2 triterpenoids oleana 2 12 diene oleana 2 13 18 diene oleana 2 18 diene ursa 2 12 diene and taraxera 2 14 diene has been identified in holocene buried mangrove sediments florida usa by comparison of the mass spectra of and by co injections with authentic standards in the oligocene brandon lignite vermont usa oleana 2 12 diene and oleana 2 13 18 diene were also identified along with two a ring contracted amyrin derivatives by comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup 2 ene from lupan 3 one these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules such as and amyrin and taraxerol the identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids

source rock quality determination from oil biomarkers ii a case study using tertiary reservoired beaufort sea oils biomarkers molecular fossils in 26 beaufort sea mackenzie delta oils reveal three genetic oil groups and suggest descriptions of their probable sources group 1 21 tertiary reservoired oils was soured from tertiary deltaic sediments group 2 three cretaceous and one devonian reservoired oil and group 3 one lower cretaceous reservoired oil derive from two high quality sources deposited in open marine environments geographical variations in the geochemistry of the 21 group 1 oils suggest that their deltaic source was substantially more oil prone in the distal deltaic portions than in the region closer to the paleoshoreline although these data do not address source rock volumes they do indicate that poor source quality is not a cause of underfilled traps in the o fshore the map pable lateral variations in group 1 oil compositions illustrate how in basins with vertically drained sources lateral source rock facies changes can bc inferred from regional variations in the geochemistry of the overlying oils furthermore the data suggest that geochemical studies attempting to deduce genetic relationships between geographically separated oils should carefully consider the potential effects of source rock facies changes on the oil compositions

characterization of acid mine drainage sources in the iberian pyrite belt base methodology for quantifying affected areas and for environmental management the present work aims to propose a methodology for quantifying the sources of acid mine drainage amd and to characterize the magnitude of the affected areas in the iberian pyrite belt sw spain such an approach allows the creation of a support tool for managing land and natural resources valorization which may be easily applied in similar mining regions the motivation and usefulness of this work can be realized by focusing on two main emerging strategic issues 1 water resources management with the example of alcolea dam that will receive water from affected areas in the iberian pyrite belt and 2 mineral resources valorization especially regarding copper exploration due to increasing market prices the used methodology included the following general steps it started with an inventory of the mines in the iberian pyrite belt followed by field cartography campaigns and finally the quantification of affected areas and contaminant discharges the results of the present work serve to confirm and quantify the magnitude of the amd pollution in the pyrite belt a total affected area of about 4 847 ha was estimated taking into account this figure and combining it with the annual average precipitation 650 l m2 results in an estimation of 31 503 680 m3 year of discharging water affected by the presence of sulphides in this scenario a total annual contribution of 260 056 tonnes year was obtained for sulphates which means more than 712 tonnes a day in the case of arsenic a toxic element the total annual contribution is more than 20 tonnes or close to 55 kg day regarding copper this economically interesting metal translates into total contributions of 10 364 tonnes year in the generating medium this gave more than 28 tonnes day which today sits at 8 200 dollars tonne this result suggests that solutions aimed at recovering this resource should be searched it may represent a financial return at the same time that it would mean overcome environmental liabilities

organic geochemical characteristics and depositional environment of the tertiary tanjong formation coals in the pinangah area onshore sabah malaysia article i nfo article history the tertiary tanjong formation coals exposed in the west middle block of the pinangah coalfield central part of southern sabah were analyzed and their depositional environments were interpreted the tertiary tanjong coals are humic and generally dominated by vitrinite with significant amounts of liptinite and low amounts of inertinite macerals total organic carbon contents toc of the coals range from 51 2 to 77 7 wt and yield of bitumen values ranging from 57 300 to 140 000 ppm which meet the standard as a source rock with good hydrocarbon generative potential in support good liquid hydrocarbons generation potential can be expected from the tanjong coals based on significant liptinitic content 15 this is supported by their high hydrogen index up to 300 mg hc g toc consistent with type ii and mixed type ii iii kerogens and py gc s2 pyrograms with n alkane alkene doublets extending beyond c30 the coal samples have vitrinite reflectance values in the range of 0 42 0 66 ro indicating immature to early mature stage for hydrocarbon generation these vitrinite reflectance values also indicated that the tanjong coals are with sub bituminous b a and high volatile bituminous c rank tmax values ranging from 419 to 451 c are good agreement with the vitrinite reflectance data this is supported by biomarker maturity parameters as suggested by the c32 homohopane the saturated fraction of the tanjong coals are characterized by dominant odd carbon numbered n alkanes n c23 to n c33 high pr ph ratios 8 18 high tm ts ratios 6 28 and pre dominant of regular sterane c29 all biomarker parameters clearly indicate that the organic matter was de rived from terrestrial inputs and deposited under oxic condition

organic geochemistry of freshwater and alkaline lacustrine sediments in the green river formation of the washakie basin wyoming u s a abstract two members of the green river formation in the washakie basin have been analysed by organic geochemical and organic petrographic techniques and the results placed in a sequence stratigraphic framework one of these members the laney shale was deposited in a hydrologically closed alkaline lake under an arid climate and was characterized by high concentrations of alginite rich organic matter whereas the other the luman tongue was deposited in a hydrologically open freshwater lake under a humid climate and consisted of organic poor profundal lake mudstones and coaly lake margin sediments potential source rocks in both lake types have the potential for generating high wax oil at high subsurface temperatures 150 175 c at a heating rate of 5 k ma but the alkaline system is clearly more prolific the most abundant biological marker hydrocarbons were the 4 methylsteranes in both lake types though dinosteranes were found only in the laney shale oleanane was absent from the luman tongue despite an abundance of angiosperm palynomorphs intraformational heterogeneities were best documented for the laney shale where molecular differences in kerogen type occur at the parasequence level with early transgression maximum transgression and rejuvenation stages of lake history having its own kerogen type and distinctive high wax oil fingerprint thermal lability was shown to be linked to kerogen structure in particular the presence of alicyclic and oxygen containing moieties and these in turn are correlated with total organic carbon content and thence productivity degree of preservation some kerogen components appear to have originated via selective preservation whereas others may have been formed by diagenetic condensation reactions

accumulation of arsenic from acidic mine waters by ferruginous bacterial accretions stromatolites in the acidic stream ph 2 2 4 of the carnoules pb zn mine gard france very high as contents from 9 to 20 can be accumulated as ferric arsenate and arsenate sulphate precipitates in rapidly growing bacteria made structures the main bacterial forms are rod shaped and sheathed their sheath is made of fe as rich material and is coated with ferric arsenate colloidal particles or may be partially included in authigenic crystals living forms ofthiobacillus type bacteria have been recognized in the precipitates the cyclic development of bacterial colonies alternating with sand deposition and erosive episodes results in the formation of as rich ferruginous accretions these laminated and dome shaped bacterial constructions are similar to those of stromatolites the extremely high contents of solute as in upstream flow 250 mg 1 are lowered by 2 3 order of magnitude downstream lead is also precipitated and concentrated in this feas rich bacterial stromatolite 2500 ppm pb this accumulation and concentration of as and heavy metals via direct or induced microbial action limits pollution downflow but seasonal storms could erode these feaspb rich deposits and drastically increase pollution the accumulation of ferric arsenate by bacterial stromatolites suggests that possible microbial remediation strategies may be used in acid mine drainage environments

the acidic mine pit lakes of the iberian pyrite belt an approach to their physical limnology and hydrogeochemistry abstract this study examines some relevant limnological and hydrogeochemical characteristics of 22 mine pit lakes of the iberian pyrite belt ipb the studied pit lakes include some of the largest and historically most important mines of the ipb including corta atalaya and cerro colorado in riotinto filon norte filon centro and filon sur in tharsis aznalcollar or san telmo and many other of minor size as a whole these lakes constitute at present a large volume of highly acidic and metal polluted water some of these pit lakes are very recent e g corta atalaya 2 5 a los frailes 6 a and present a continuous hydrological and geochemical evolution although many others were abandoned decades ago and show nearly constant water volume depth profiles obtained in several pit lakes e g san telmo confesionarios cueva de la mora concepcion indicate that many of them have developed meromixis and show at present a permanent thermal and chemical stratification with a well defined chemocline separating an anoxic fe ii rich monimolimnion and a well mixed oxygenated and fe iii rich mixolimnion in the upper layer the bacterial oxidation of fe ii competes with photoreductive processes which take place in the surface water thus provoking diel cycles of fe ii concentration the observed water chemistry reflects the oxidation and dissolution of pyrite and other sulphides and gangue aluminosilicates from the country rock the pit lakes of the ipb cover a wide range of water compositions from circumneutral and relatively low metal e g los frailes ph 7 2 0 07 mg l fe 3 8 mg l mn 30 mg l zn to extremely acidic and metal loid rich e g corta atalaya ph 1 2 36 7 g l fe 6 7 g l zn 1 3 g l cu 159 mg l as most pit lakes however are comprised within the ph range of 2 2 3 6 and appear to be strongly buffered by the hydrolysis and precipitation of fe iii in the form of schwertmannite which forms colloids that can sorb trace elements from the aqueous phase

complex patterns of steroidal biomarkers in tertiary lacustrine sediments of the biyang basin china gas chromatography gc gas chromatography mass spectrometry gc ms and gas chromatography mass spectrometry mass spectrometry gc ms ms with co injected synthetic standards were used to analyse the biomarker patterns of some tertiary lacustrine clayey dolomites from the biyang basin china the lithology low pr ph ratio and high gammacerane content of these sediments indicated that high salinity prevailed during their deposition the distributions of steroidal hydrocarbons were particularly unusual and several pseudohomologous series including regular steranes c27 c29 4 methyl steranes c28 c30 including dinosteranes 3b ethyl steranes c29 c31 lanostanes c30 c32 and a variety of other 3b alkylated steranes were identified 3b n propylcholestane 3b n propylstigmastane and 4 4 dimethylcholestane were identified using authentic standards and this is the first time these compounds have been unambiguously characterised in sediments crown copyright 2001 published by elsevier science ltd all rights reserved

acid mine drainage in the iberian pyrite belt odiel river watershed huelva sw spain geochemistry mineralogy and environmental implications abstract this work reports the physical properties and water chemistry of 64 amd discharges from 25 different mines in the ipb draining to the odiel river watershed which have been investigated during the hydrologic year 2003 2004 these amd solutions vary largely in flow rate and chemical composition both spatially between the different mine sites suggesting a strong geologic control on amd chemistry and seasonally due to marked hydrologic variations and include cases with very low ph mostly in the range 1 4 4 and extreme sulphate up to 44 g l so 4 2 and metal content e g up to 7 7 g l fe 2 6 g l al or 1 4 g l zn different hydrogeochemical facies of amd namely fe ii anoxic fe iii suboxic and aluminous oxic are recognized in the field as a response to the continuous oxidation and hydrolysis of dissolved fe relevant geochemical aspects of these amd environments are discussed including i the redox chemistry of the fe ii fe iii couple ii the reaction rates for bacterially catalyzed oxidation of fe ii and hydrolysis of fe iii iii the role played by dissolved fe and al in the acidity and chemical buffering of the amd systems and iv the solubility and trace metal retention capacity of the fe oxyhydroxysulphate and hydrated sulphate minerals commonly associated with amd in addition the mineralogy and chemistry of the fe precipitates schwertmannite jarosite goethite ferrihydrite al phases e g basaluminite and mg fe al efflorescent so4 salts e g epsomite hexahydrite copiapite halotrichite rozenite coquimbite present in the amd generating mine sites have also been studied the mineralogy of the fe precipitates is well correlated with the water ph with jarosite at ph 2 schwertmannite at ph 2 4 basaluminite at ph 4 5 and ferrihydrite at ph 6 schwertmannite appears to be the most important mineral phase both in controlling the fe solubility at ph 2 4 and as sorbent of trace elements as cu zn which favours natural attenuation finally a basin scale environmental perspective is given in order to evaluate the impact of amd on the water quality including calculation of metal loadings transported by amd from the most important mine districts in the province

differential transportation and deposition of terrestrial biomarkers in middle eocene fluvial to estuarine environments hokkaido japan abstract higher plants constitute a significant portion of sedimentary organic matter in middle eocene fluvial floodplain estuarine sedimentary rocks exposed in the bibai region of central hokkaido japan the differential transportation and deposition of terrestrial biomarkers were studied in this area the distribution of higher plant and fungal biomarkers in the bibai non marine sedimentary rocks was constrained by sedimentary facies and lithology claystones and siltstones lacking coaly fragments tended to be rich in angiosperm biomarkers whereas coal and coaly mudstones were comparatively rich in gymnosperm biomarkers perylene a possible fungal biomarker was detected in fine grained floodplain deposits facies and lithologic controls on terrestrial biomarker distribution can be attributed to the differential transportation and deposition of organic debris and degradation products derived from higher plants and fungi redox potential of the depositional environment is another important factor for the formation and preservation of terrestrial aromatic biomarkers reconstruction of land based paleovegetation from terrestrial biomarkers in non marine sediments requires careful consideration of the differential transportation and preservation of precursory terrestrial organic compounds

field multi step limestone and mgo passive system to treat acid mine drainage with high metal concentrations abstract passive treatment systems have become one of the most sustainable and feasible ways of remediating acid mine drainage amd however conventional treatments show early clogging of the porosity or and coating of the reactive grains when high acidity and metal concentrations are treated the performance of fine grained reagents dispersed in a high porosity matrix of wood shavings was tested as an alternative to overcome these durability problems the system consisted of two tanks of 3 m 3 filled with limestone sand and wood shavings and one tank of 1 m 3 with caustic magnesia powder and wood shavings separated by several oxidation cascades and decantation ponds the system treated about 1 5 m 3 day of amd containing an average of 360 mg l fe 120 mg l al 390 mg l zn 10 mg l cu 300 g l as and 140 g l pb a mean ph of 3 08 and a net acidity of 2500 mg l as caco 3 equivalent the water reached ph 5 and 6 in the first and second limestone tanks respectively suitable to remove trivalent metals and ph 8 9 in the mgo tank suitable to remove divalent metals after 9 months of operation the system achieved an average removal of 100 al cu as pb more than 70 fe about 25 zn and 80 acidity goethite schwertmannite hydrobasaluminite amorphous al oh 3 and gypsum were the main precipitates in the two limestone tanks precipitation of divalent metals fe ii zn and traces of cd ni and co were complete inside the third tank of mgo but preferential flow along the walls was responsible for its low treatment performance goethite gypsum zn schulenbergite and sauconite are the crystalline solid phases identified in the mgo tank

the natural attenuation of two acidic effluents in tharsis and la zarza perrunal mines iberian pyrite belt huelva spain the geochemical evolution of two acid mine effluents in tharsis and la zarza perrunal mines iberian pyrite belt huelva spain has been investigated in origin these waters present a low ph 2 2 and 3 1 and high concentrations of dissolved sulphate and metals fe al mn cu zn as cd co cr ni however the natural evolution of these acidic waters which includes the bacterial oxidation of fe ii and the subsequent precipitation of fe iii minerals represents an efficient mechanism of attenuation this self mitigating process is evidenced by the formation of schwertmannite which retains most of the iron load and by sorption toxic trace elements like as the later mixing with pristine waters rises the ph and favours the total precipitation of fe iii at ph 3 5 and subsequently al compounds at ph 4 5 along with the sorption of trace metals mn zn cu cd co ni until chemical equilibrium at circumneutral conditions is achieved

tertiary oils from upper assam basin india a geochemical study using terrigenous biomarkers abstract the upper assam basin in northeast india is a tertiary sub basin of the assam arakan basin hydrocarbons are present in the langpar formation upper palaeocene lakadong member of the sylhet formation lower eocene and the barail oligocene tipam lower miocene and girujan middle miocene formations in the basin a detailed study to understand the nature and origin of the oils from different stratigraphic horizons using terrigenous and other biomarkers has been carried out further the variation in maturities of oils occurring in different stratigraphic horizons has also been studied the study shows that rearranged oleananes oleananes and bicadinanes are present in these oils implying land plant input to their source rocks the oils have been classified into different groups using ratios of rearranged oleananes oleananes bicadinanes and steranes indicating presence of multiple source rocks in the basin with subtle variation in characteristics maturity studies show that oils from younger horizons barail tipam and girujan are more mature than oils from older horizons langpar and lakadong there is an apparent mismatch in maturity of oils as measured by different biomarker maturity parameters this is due to the mixing of two different charges of oils having different maturities and generated from two different source rock kitchens in the same reservoir principal component analysis pca of biomarker data has also been able to classify the oils into various groups a new parameter has been developed using ratios of rearranged oleananes for determining maturity of these oils

biomarker and n alkane isotope profiles for tertiary oils relationship to source rock depositional setting abstract biomarker and n alkane isotope profiles have been measured for 29 late cretaceous tertiary oils from se asia china papua new guinea new zealand and the u s a the results are interpreted with respect to six kinds of source rock depositional setting fluvio deltaic fd freshwater transitional tr lacustrine lac saline lacustrine sal marine deltaic md and marine carbonate mc a comparison of biomarker and n alkane isotope results suggests that parameters such as the oleanane hopane ratio may overestimate the higher plant contribution to marine oils the abundance of bicadinanes is much more variable than that of oleanane probably because of a specific association with the highly resinous dipterocarp hardwoods of se asia however traces do occur in an oil from outside the paleogeographic range of the dipterocarp family confirming that there is also a more general angiosperm source the bicadinane isomeric distribution is shown to depend on maturity leading to new maturity parameters which are resistant to even very heavy biodegradation retention indices based on the regular hopane series are provided for the main bicadinane and methyl bicadinane isomers and for a group of oleanane related triterpanes of unknown structure the presence of the latter compounds may indicate locally deposited as opposed to transported higher plant matter in the source source rock depositional setting is the primary control on the shape of the n alkane isotope profile with negatively sloping curves being characteristic of fd and tr oils and flat or positively sloping curves typical of marine oils the difference is probably related to the bacterial reworking of higher plant matter in the fd environment a slight isotopic anomaly at n c 17 correlates with the abundance of algal derived steranes and may indicate a minor marine contribution to the source of an fd oil

coupling effect of fe3 aq and biological nano sized fes coated limestone on the removal of redox sensitive contaminants as sb and cr implications for in situ passive treatment of acid mine drainage nano sized fes particles have been shown to improve the adsorption performance in permeable reactive barrier prb technologies that are used to treat acid mine drainage to investigate the coupling effect of fe3 and biological nano sized fes on removal of redox sensitive contaminants and the permeability of a limestone system fe reducing bacteria frb and sulfate reducing bacteria srb were used to form nano sized fes coatings on limestone grains for initial acidic solutions containing 0 5 mg l as v cr vi and sb v retardation factors increase from 26 5 and 7 respectively in a limestone only pristine system to 367 89 and 9 respectively in an fes coated limestone system and to 345 367 and 308 respectively in an fes fe3 aq system the permeability coefficient of the fes coated limestone system is better than that of the pristine limestone system but declines to two thirds of the pristine limestone system in the presence of fe3 aq possibly due to the formation of secondary ferric hydroxides xps analysis suggests that the fes particles are effective at reducing as v sb v and cr vi and removing them from solution these results demonstrate that fes particles improve retention of redox sensitive contaminants with and without fe3 aq these new findings give new insights on the coupling effect of redox systems used in prbs

petroleum generation and migration from talang akar coals and shales offshore n w java indonesia abstract the oligocene talang akar formation is the major source for petroleum oil and gas in the ardjuna sub basin source rock quality varies within the deltaic to marginal marine complex with coals deposited on the lower delta plain being distinctly oil prone whereas the surrounding delta plain shales are largely gas prone shales and drifted coals laid down in marine influenced interdistributary bay environments show increasingly oil prone characteristics possibly due to preferential transport of hydrogen rich plant components to more distal setting molecular characteristics of the coals and shales are similar with higher plant angiosperm biomarkers and their aromatic derivatives occuring widely kinetic studies of hydrocarbon generation and stimulated maturation experiments using hydrous pyrolysis indicate that the delta plain coals are the major source for crude oils in the basin with a secondary but minor contribution from marine influenced interdistributary bay shales delta plain shales are interpreted to expel gaseous products only the stratigraphic and spatial location of oil and gas fields were examined with respect to their position relative to oil and gas generating source rocks the field distribution could not be explained in terms of source rock geochemistry alone and phase behavior of petroleum during secondary migration was shown to exert an important influence on the distribution of oil and gas deposits in the basin

the ratios of dibenzothiophene to phenanthrene and pristane to phytane as indicators of depositional environment and lithology of petroleum source rocks abstract the ratio of dibenzothiophene to phenanthrene and the ratio of pristane to phytane when coupled together provide a novel and convenient way to infer crude oil source rock depositional environments and lithologies such knowledge can significantly assist in identifying the source formation s in a basin thereby providing valuable guidance for further exploration the ability to infer this information from analysis of a crude oil is especially valuable as frequently the earliest samples in a new area may be shows and or drill stem test samples from exploratory wells which are characteristically drilled on structural highs stratigraphically remote from the source formation s a cross plot of dibenzothiophene phenanthrene versus the pristane phytane ratios measured on seventy five crude oils from forty one known source rocks ranging in age from ordovician to miocene consistently classified the oils into the following environment lithology groups marine carbonate marine carbonate mixed and lacustrine sulfate rich lacustrine sulfate poor marine and lacustrine shale and fluvial deltaic carbonaceous shale and coal the dibenzothiophene phenanthrene ratio alone is an excellent indicator of source rock lithology with carbonates having ratios 1 and shales having ratios the dibenzothiophene to phenanthrene and the pristane to phytane ratios can also be used to classify source rock paleodepositional environments the classification scheme is based on the premise that these ratios reflect the different eh ph regimes resulting from the significant microbiological and chemical processes occurring during deposition and early diagenesis of sediments the dibenzothiophene phenanthrene ratio assesses the availability of reduced sulfur for incorporation into organic matter and the pristane phytane ratio assesses the redox conditions within the depositional environment interpretation of these ratios has been aided by quantitative biomarker analysis and by carbon isotope data for pristane and phytane obtained by gas chromatography isotope ratio mass spectrometry

iron and aluminum hydroxysulfates from acid sulfate waters acid sulfate waters are produced mostly by the oxidation of common sulfide minerals such as pyrite chalcopyrite pyrrhotite and marcasite in rocks soils sediments and industrial wastes this spontaneous process of mineral weathering plays a fundamental role in the supergene alteration of ore deposits the formation of acid sulfate soils and the mobilization and release of acidity and metals to surface and ground waters the purely natural process of acid rock drainage is often intensified by human activities related to mining mineral processing construction soil drainage and dredging geochemical reaction rates are accelerated because physical disturbance gives greater exposure of mineral surfaces to air and water and to microbes that catalyze the reaction process large quantities of reactive sulfides are also concentrated and exposed to air as a result of mining and mineral processing acid sulfate waters produce a number of fairly insoluble hydroxysulfate and oxyhydroxide minerals that precipitate during oxidation hydrolysis and neutralization the objective of this chapter is to describe the formation properties fate and environmental implications of the nano to microphase hydroxy sulfates of fe and al that are precipitated from acid sulfate waters these minerals are commonly of poor crystallinity and difficult to characterize much remains to be learned about their occurrence formation and properties mine drainage the best known examples of acid sulfate waters are those released from mines where coal and metallic sulfide ores have been exploited ash et al 1951 barton 1978 nordstrom 1982a rose and cravotta 1998 nordstrom and alpers 1999 there may be as many as 500 000 inactive or abandoned mine sites in the united states alone lyon et al 1993 although most of these pose no immediate water quality problem kleinmann 1989 estimated that about 19 300 km of streams and more than 72 000 ha of lakes and reservoirs have been

oleananes in oils and sediments evidence of marine influence during early diagenesis abstract the oleananes as markers for the angiosperms provide valuable source and age information when present in an oil nevertheless they are not quantitatively related to the land plant input and indeed their presence reflects only a small leak in diagenetic processes leading primarily to aromatic oleanoids because they are minor products the abundance of oleananes in terrigenous oils and sediments may be highly sensitive to changes in early diagenetic conditions here we present evidence that contact of plant matter with seawater during early diagenesis enhances the expression of oleananes in a mature sediment or oil oleananes are absent or present at very low concentrations in samples from the base of an eocene coal seam affected by postdepositional seawater intrusion however their abundance increases toward the top of the seam in correlation with organic sulphur dibenzothiophene phenanthrene and the homohopane index similarly in deltaic sediments from the south sumatra basin oleanane hopane is strongly correlated with indicators of marine influence such as c 27 c 29 steranes and the homohopane index in each case increasing oleanane abundance is accompanied by a reduction in the extent of aromatisation and for the south sumatra basin the proportion of a ring contracted oleananes an angiosperm derived miocene coal from the philippines deposited under freshwater conditions shows abundant aromatic oleanoids but no oleananes these results show that oleananes need to be used with caution as age and source markers in fluvio deltaic and lacustrine petroleum systems on the other hand their sensitivity to early diagenetic conditions may make them useful in locating effective source rocks in such systems

statistical properties of arctic sea ice morphology derived from sidescan sonar images abstract using a transparent overlay technique the authors have classified a 140km long stretch of sidescan sonar imagery of the arctic sea ice underside 700m swath width into regions occupied by unique ice types the categories used were multi year ice first year ice pressure ridge apparently open dark lead apparently refrozen bright lead and randomly deformed ice the technique was validated by comparing these classifications with data obtained simultaneously using a narrow beam upward looking sonar the pattern of ice types thus observed was tested statistically for associations between adjacent regions the distribution of lead widths spacings and orientations and the distribution of ridge spacings and orientations significantly non random sequences of ice types were observed lead orientations and spacings were clustered and were set to preferred values and ridge spacings fitted a negative exponential distribution the extent of uniformly deformed ice with no apparent linearity was much greater on the underside of the ice than has ever been observed on the upper surface

a geochemical appraisal of oil generation in the taranaki basin new zealand from a basin wide evaluation of organic geochemical data it has been possible to characterize and differentiate various source rock units and to establish the genetic relationships of oils most of the oils are primarily terrestrially sourced and it is possible to recognize varying contributions from source rocks within the paleogene kapuni group and late cretaceous pakawau group this distinction is attributable to the rise to dominance of angiosperms over gymnosperms in coastal plain swamp communities by the eocene apart from the maui family i e maui field maui 4 and moki 1 oils the inferred relative contributions from the main source rock types generally correlate with the relative proportions of suitably thick and mature units near reservoirs given that mos cretaceous sourced oil appears to have escaped prior to trap development maui family oils do appear to be primarily sourced by rakopi formation late cretaceous coals in the northern part of the taranaki peninsula where heat flows are highest mangahewa kaimiro formation eocene coals are the chief sources of oils farther south in the kapuni and kupe south fields farewell formation paleocene coals appear to be the main oil source rocks biomarkers suggest that the onset of oil expulsion from coals occurs at a maturity level corresponding to a vitrinite reflectance of ca 0 8 ro and may be aided by the evolution of large volumes of carbon dioxide the terrestrial influence on paleogene source rocks diminishes to the north northwest of the basin and increasing marin contributions to oils are observed a late paleocene marine black shale is the source of oil in the kora volcanic structure it is possible that shales interbedded with coals reflecting periodic marine incursions of coastal flood plains also contribute to oil generation throughout much of the basin

aliphatic and aromatic triterpenoid hydrocarbons in a tertiary angiospermous lignite abstract the hydrocarbon biomarker assemlage of a liptinite rich early tertiary angiospermous lignite has been characterized the biomarker fistribution for the lignite confirms the low maturity and previous paleobotanic interpretations the aliphatic hydrocarbon fraction consists predominantly of n alkanes showing a strong odd carbon predominance and numerous de a triterpenoids and triterpenoids derived from higher plants bacterially derived triterpenoids were represented primarily by homohopanes and hopenes the aromatic hydrocarbon fraction contains a series of mono di and triaromatic de a triterpenoids and mono tri and tetraaromatic triterpenoids derived from higher plants the concentration and abundance of monoaromatic triterpenoids containing one to three additonal degress of unsaturation have not seen previously observed in a single deposit as such a diagenetic scheme for angiosperm derived triterpenoids is presented which confirms and extends previous hypothesis

trimethylnaphthalenes in crude oils and sediments effects of source and maturity abstract three sedimentary sequences and a number of crude oils have been analysed for trimethylnaphthalenes tmns using gas chromatography the sediments were found to contain enhanced relative abundances of 1 2 5 tmn and 1 2 7 tmn in samples of cretaceous age and younger this was especially pronounced in lower maturity sediments containing type iii organic matter older samples containing type iii organic matter were found to contain enhanced relative abundances of 1 2 5 tmn and lower relative abundances of 1 2 7 tmn 1 2 7 tmn appears to be derived directly from the structural degradation of oleanane type triterpenoids present in angiosperms and as such is proposed as a marker for this class of plant and indirectly therefore also for samples deposited since the early cretaceous the crude oils have been classified according to their trimethylnaphthalene compositions this classification enables crudes of higher plant origin to be identified and to be further classified according to whether the organic matter pre dated or post dated the evolution of angiosperms

tertiary deltaic and lacustrine organic facies comparison of biomarker and kerogen distributions abstract biological marker and kerogen compositional data in tertiary deltaic and lacustrine settings were compared and contrasted the two settings are represented by a coals and organic carbon rich shales in a ick deltaic sequence from the far east constituting three distinct organic facies and b humic coals and spropelic oil shales in a restricted intermontane freshwater lacustrine sequence from western montana u s a constituting two distinct organic facies wedistinguish the organic facies in each depositional setting by systematic differences in gross compound class distributions kerogen and infrared spectral characteristics molecular character of pyrolyzates sterane carbon number distribution and sterane hopane ratios the kerogens of the three deltaic organic facies are characterized by varying quantities of vitrinite resinite sporinite cutinite and fluorescent amorphinite triterpane distributions reveal numerous terrigenous compounds including oleanane oleanenes and unidentified c 30 presumably resin derived components the two organic facies of the freshwater lacustrine setting are distinguishedased upon either a vitrinite or an alganite fluorescent amorphinite predominance in the kerogen numerous characteristics facies related markers are also present including dehydroabietane land plant resins and 4 methylsteranes perhaps from freshwater dinoflagellate input the available molecular and petrographic data are evaluated and characteristics are proposed for distinguishing five organic facies of these two depositional settings the successful simultaneous use of molecular geochemistry and organic petrography in this study provides a format for refining the organic facies concept

chemostratigraphic evidence of higher plant evolution in the taranaki basin new zealand correlation between palynological and biomarker records of higher plant development during the cretaceous and paleogene in taranaki basin new zealand is good gymnosperms particularly podocarps were the chief members of coastal plain swamp flora during the late cretaceous and contributed significant quantities of diterpanes often dominated by isopimarane to organic rich sediments angiosperms increased in relative abundance through the paleocene and became the dominant higher plants in the eocene their contributions to coaly sediments are characterized by various triterpanes particularly 18 h oleanane and its c24 a ring degraded counterpart this change in dominance of higher plant groups can be followed by the use of an angiosperm gymnosperm index agi based on the relative concentrations of selected triterpanes and diterpanes in mz 191 and mz 123 mass chromatograms plant biomarker distributions do not provide as precise age indications as do pollen assemblages but they may be more representative of the vegetation growing in a particular area of a peat swamp

diagenesis of higher plant triterpenes in evaporitic sediments abstract several samples from a tertiary carbonated evaporitic series sainte cecile camargue france were investigated their analysis revealed a high abundance of new or uncommon hydrocarbons and organic s compounds related to higher plant triterpenes several of them in particular 12 29 cyclolupa 12 18 20 29 triene 1 could be positively identified these triterpenoids are generally absent from non evaporitic sediments which contain essentially aromatic triterpenoids resulting from microbially mediated aromatization processes starting in ring a or in ring b when preceded by the loss of ring a the uncommon transformations undergone by higher plant triterpenes in the highly anoxic sediments from sainte cecile are specific for each series of triterpenes i e oleanane ursane lupane and are probably linked with the rapid disappearance of the functionality located in ring a by reduction or by the incorporation of the triterpenes in s rich macromolecules by reaction with inorganic s species these biological markers represent new source parameters which may be quite useful as indicators of terrestrial inputs in evaporitic deposits