The Anna Shale (Pennsylvanian) is an organic-rich, marine black shale that commonly overlies the Herrin (No. 6) Coal of the Carbondale Formation, Illinois Basin. Disk-shaped iron sulfide concretions, called pyrite suns, which are commonly up to 10 cm or more across are found in the lowest few centimeters of the Anna Shale in coal mines near Sparta in southwestern Illinois. This area is the only known location where pyrite suns of this size have been found, suggesting that unusual geochemical and/or depositional conditions led to their formation. The primary objective of this study was to evaluate the geochemical conditions at the time of Anna Shale deposition in the area where the pyrite suns formed.

The purpose of this study is to identify and analyze the geochemical facies of the Hushpuckney Shale using XRF scanning data and the bioturbation indices, which will contribute to a better understanding of the biogeochemical environment prevalent during the deposition of the Hushpuckney Shale. The Hushpuckney Shale Member of the Swope Formation (Kasimovian Stage) preserved in KGS Spencer core 2 - 6, consists of a black shale submember overlain by bioturbated gray shale. Millimeter-scale core description and analysis of XRF scanning data enables identification of geochemical facies within the study core and contributes to understanding the environment of shale deposition. The XRF spectrometer produces X-ray image of the core and abundance values of selected major and trace elements, including iron (Fe), calcium (Ca), sulfur (S), molybdenum (Mo), zinc (Zn), vanadium (V), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), zircon (Zr), potassium (K) and phosphorous (P). Canfield and Thamdrup's (2009) classification of geochemical environments is used to recognize oxic/aerobic, manganous-nitrogenous, ferruginous and sulfidic facies within the black shale submember. A modification of Droser and Bottjer's (1986) semi-quantitative field classification of bioturbation is used to identify facies variations within the gray shale submember. Abundance of apatite nodules and lamina in the black shale submember of the study core suggest that black shale sediments accumulated slowly in a sediment-starved basin. A high abundance of sulfide-scavenged elements, including Mo, Zn, V, Ni and Cr, identifies the sulfidic facies in the black shale submember, and indicates deposition in an oxygen-depleted environment with a high concentration of hydrogen sulfide. The overlying ferruginous facies has lower abundances of sulfide-scavenged elements and lacks cryptic Fe-laminations. The uppermost black shale submember facies, the manganous-nitrogenous facies, has cryptic Fe laminations and a relatively high P/Ca ratio. Abundance of cryptic iron laminations and apatite nodules and lamina indicates the syngenetic deposition of iron and phosphate due to Fe-P coupling mechanism. The gray shale submember is burrowed, indicating deposition under oxygenated conditions. Bioturbation indices reveal the variations in the intensity and nature of burrows within the gray shale, which corresponds to the changes in the depositional environment that may be related to the rise and fall of sea-level.

The Cleveland Shale displays a characteristic and distinctive pattern of promontories and recessed intervals on weathered outcrops, which appears to represent cyclicity. This weathering pattern can be observed in other shales, both within and outside the Appalachian Basin; so determining the nature of these cycles may be critical for understanding the origin of, not only the Cleveland Shale, but also of black shales in general. Cyclicity in the Cleveland was examined on a decimeter-to-meter scale using lithologic characterization, gamma-ray stratigraphy and x-ray fluorescence, and on a millimeter-to-centimeter scale using organic petrography. Lithologic characterization and gamma-ray stratigraphy revealed Milankovitch-band fourth- and fifth-order cyclicity related to changes in the earth’s orbital eccentricity (100 ka) and obliquity of the earth’s axis (42 ka), respectively. Sedimentological changes associated with these cycles were identified through organic petrography and x-ray fluorescence. A depositional model was developed from these data sets, which suggests that cyclic changes in local climate — from cold and wet to warm and dry — controlled advancing and retreating glaciation in the adjacent Acadian mountains as well as concomitant sea-level rise and fall in the Black-Shale Sea. Such changes would have controlled sediment influx to the sea and are thought to be reflected in the cycles.

Le Bassin de Franceville situé au SE du Gabon présente une série de black shales (Formation FB) d'âge Paléoprotérozoïque (2.1 Ga) surmontant les grès de la Formation FA. Ce bassin peu déformé et non métamorphique représente une archive exceptionnelle des processus de dépôt de cette période de l’histoire de la Terre où la vie commence à se développer. En particulier, la Formation FB contient le protore d'un gisement mondial d'oxydes de manganèse exploité par la société Eramet-Comilog. L’objectif de ce travail est de préciser les conditions de formation de ce protore et de le replacer dans l’histoire du remplissage du bassin. Ce protore d'une épaisseur moyenne de 75 m est constitué de carbonates de manganèse ; il a fait l'objet d'une récente campagne de 24 forages carottés d'une profondeur moyenne de 125 m sur le plateau de Bangombé (Pl. Bangombé).A travers une approche pluridisciplinaire comprenant l'étude de ces forages et des affleurements clefs du bassin, ce travail porte sur la caractérisation i) de l'environnement de dépôt du protore et des séries qui l'encadrent (du toit du FA au toit du FB) ; ii) du mode de formation des carbonates de Mn à 2.1 Ga et iii) de l'architecture et de la répartition des hautes teneurs en Mn du protore représentant un gisement potentiel du futur.L’étude pétro-sédimentaire détaillée a permis de distinguer neuf unités (U1 à U9) au sein de la Formation FB organisées suivant un cycle rétrogradant jusqu’à U5 puis progradant jusqu’à U9. Ce découpage montre une évolution du milieu de dépôt depuis un domaine de shoreface contrôlé par des courants deltaïques (U1) évoluant vers des dépôts d’offshore restreint (U2). Ce bassin enregistre ensuite un système de chenaux-levées turbiditiques (U3) qui alimentent un réseau d'injectites reconnu sur l’ensemble du Pl. de Bangombé et qui traverse 150 m de série (U4 à U7) en affectant le protore et ainsi les teneurs en Mn. L'environnement de dépôt du protore (U5 et U6) marque l’isolement du bassin qui devient affamé et contrôlé par une sédimentation biochimique à l’origine du dépôt des carbonates de Mn. L'Unité 7 correspond à la réouverture des apports détritiques en domaine d'offshore supérieur puis en domaine de shoreface dominé par des dépôts de tempêtes et de chenaux sous-aquatiques deltaïques (U8), et enfin lagunaire (U9) dans lequel apparaissent les premiers métazoaires de l’histoire de la planète, suivant une séquence régressive.Une étude géochimique a permis de préciser les conditions de dépôt du protore qui se forme en milieu alcalin anoxique à sub-oxique. Dans ce milieu, nous montrons pour la première fois une précipitation directe des carbonates de Mn sous forme bactériomorphe induite par l'activité photosynthétique des cyanobactéries qui consomment le CO2/HCO3 et conduisant à une augmentation du pH favorable à la formation des carbonates de Mn. L'activité cyanobactérienne est conditionnée par l’absence de courants de fond qui augmentent la turbidité du milieu et stoppent cette dernière.Les corrélations diagraphiques et séquentielles permettent de préciser la répartition spatiale et temporelle du FB permettant ainsi de replacer le protore dans l’histoire tectono-sédimentaire du bassin. Une première phase syn-tectonique (U1 à U3) contrôle l’épaisseur et la mise en place de dépôts turbiditiques dans les parties subsidentes, de dépôts argileux sur les pentes et de dépôt de carbonates sur les hauts-fonds. La seconde phase post tectonique (U4 à U7) permet la mise en place de dépôts relativement isopaques, bien que le protore enregistre une subsidence plus importante au nord du Pl. de Bangombé. On observe ainsi, sur le Pl. de Bangombé, des teneurs en Mn qui augmentent vers le sud alors que l’épaisseur du protore augmente vers le NNE. Postérieurement au dépôt du FB, le protore est structuré par des failles qui le compartimentent en touches de piano limitant ainsi sa continuité sur le Pl. de Bangombé. / The Franceville Basin (2.1 Ga) in southeastern Gabon, hosts a black shale series well preserved (FB Formation) which represents an exceptional example of unmetamorphised Paleoproterozoic sediment strata. This basin includes the protore of one of the largest Mn-oxide laterite ore worldwide, mined by Eramet-Comilog. The aim of this this work is to determine formation conditions of this protore and to characterize the global sedimentary evolution of the FB Formation which include the protore. This 75 m thick protore is constituted of Mn carbonate-rich black shales which represent a potential ore deposit for the future. It was drilled, on the Bangombé plateau, during a recent campaign of 24 boreholes with an average depth of 125 m.Through multidisciplinary study on these cores and key outcrops of the basin, this work focuses on : i) the depositional environment of the Mn-protore and FB Formation ; ii) the processes of formation of the Mn-carbonates at 2.1 Ga and iii) the architecture and distribution of Mn-rich levels of the protore on the Bangombé Plateau.A detailed sedimentological and petrological study allowed us to redefine the division of the FB into nine units, named U1 to U9 from the base to the top. These units show a fine upward cycle up to U5 and a reverse coarse loop until U9. This division leads to a new interpretation to propose an evolution from a shoreface depositional environment controlled by deltaic currents (U1) to an offshore depositional environment with anoxic conditions (U2). In this basin, a system of submarine fan is developed, feeding a network of sand injections (injectites) covering the Bangombé plateau (70 km²) and with a thickness of 150 m affecting U4 to U7, including the Mn-protore. The protore depositional environment formed below the wave base limit (U4, U5 and U6) in a starved basin, controlled by biochemical sedimentation allowed the formation of Mn-carbonates. The end of starved basin, would allow the re-opening of the detrital input into the offshore basin (U7). This basin is then filled by storm bar deposits intersected by deltaic sub-aquatic channels (U8). The U9 unit corresponds to a quiet lagoon environment, allowing the multicellular organism development for the first time on the planet.A geochemical study allowed the characterization of the depositional environment of Mn-carbonates as an anoxic to sub-oxic and alkaline environment. For the first time, we showed that the manganese carbonates, present as bacteriomorph forms, are precipitated from the seawater by the mediated photosynthetic cyanobacterial activity, which allows CO2 / HCO3 depression of the environment and a local increase of pH. The cyanobacterial activity is controlled by the absence of bottom currents, which increase the detrital input. This would stop the activity of the cyanobacteria and thus would lead to the decrease of the Mn-concentration along the protore.Finally, well-log and a sequential correlation analyses allowed us to detail spatial and timing repartition of FB Formation deposit, controlled by a tectono-sedimentary model. We propose two- tectono-sedimentary phases. A first syn-tectonic phase (U1 to U3) controls the depocentres and sedimentation gaps. Turbidite coarse deposits are located in the most subsident part, clay deposits rather on the slope and carbonates on shoals. A second post-tectonic phase (U4 to U7) allows isopach deposits. The Mn-protore formed during the post-tectonic phase. However, it shows a variable thickness due to subsidence to the north of the Bangombé plateau. So, on the Bangombé plateau, Mn-contents increase towards the south, whereas the protore thickness increases towards the NNE. Moreover sand injectites decrease Mn-content in the eastern part of the Bangombé plateau and impact on the economic evaluation of the Mn-carbonates. Currently, the protore is structured by post-sedimentary faults, which lead to a non-continuity of the high Mn levels on the Bangombé plateau.

Réalisée dans le cadre du projet UE Bioshale, cette thèse vise à comprendre les processus de concentration des métaux dans les gisements de black shale, et à valoriser ces minerais par voies hydro- et biotechnologiques. La matière organique (MO), peu mature, du minerai de Lubin (Kupferschiefer) est intervenue dans les processus syn-, dia- et épigénétiques de concentration des métaux. Le cuivre (>7%) ainsi que Ag, Co, Ni, Pb, Zn,... y sont principalement présents sous forme de chalcocite, covellite, bornite, chalcopyrite... Certains éléments (Cu, Fe, Co, Ni, V) se retrouvent à de faibles teneurs dans la MO (=0,2%). La MO plus mature de Polkowice (Kupferschiefer), contient moins d'éléments associés (Fe, V, S). Les teneurs en métaux de base y sont plus faibles (<1% Cu), mais avec de l'or et du sélénium sous forme d'électrum et clausthalite. A Talvivaara, le minerai, graphitique, peu riche (Zn+Cu+Ni<1%), comprend pyrrhotite-pyrite (± chalcopyrite, alabandite, pentlandite, sphalérite). Tectonique et métamorphisme ont ici effacé tout lien entre processus minéralisateurs et MO (qui ne contient pas de métaux). Les traitements des minerais de Lubin et de Talvivaara aboutissent à une mise en solution des métaux plus élevée en réacteur (>90%) que par lixiviation en tas (<75% à Talvivaara). Ces taux dépendent peu voir pas de la présence de la MO. Quelque soit le traitement, la chalcocite, la digénite, la bornite et la pyrrhotite sont plus facilement lixiviables que la pyrite et la chalcopyrite. Le biotraitement du minerai de Lubin ne permet pas la récupération de Ag et Pb. Cependant, plus de 92% de ces éléments sont solubilisés par un traitement additionnel du résidu de biolixiviation.

The Black Shale Basin of West Texas covers an area in excess of 21,000 square miles and includes the region from Terrell and Pecos Counties eastward to Menard and Kimble Counties. It extends from Real, Edwards, and Val Verde northward beyond Glasscock and Upton Counties. This basin includes such local basins as the "Midland Basin," and "Val Verde Basin," of Frank E. Lewis, the "Sheffield Channel," and the "Kerr Basin." Reasons are given for the belief that the black shale sediments in this basin were derived from rocks south of this area. The shale ranges in age from Bend (lower Pennsylvanian) through Clear Fork (middle Permian). The shale of the Midland Basin has been divided into three distinct zones. Pre-Cretaceous erosion has removed the offlapping Permian shale in the extreme southern portion of the area leaving Pennsylvanian directly beneath the Trinity. The problem of stratigraphy is complicated by gradation and lack of diagnostic fossils. There is a great divergence of opinion as to correlative formational units derived from a study of the well cuttings. / text

The environment of deposition of the Ohio Shale of the Appalachian Basin has been studied extensively using various geochemical proxies for each of its members. The accumulation of organic matter (OM) and its preservation in the Late Devonian-Early Mississippian black shales of central Kentucky have been studied extensively, especially the possible correlations between trace metal contents and water-column oxygenation. Previous work has centered on geochemical, petrographic, and isotopic analysis of samples collected throughout the central Appalachian Basin. Mechanisms for OM preservation include high productivity, enhanced preservation due to dysoxic or anoxic bottom waters, and a feedback loop due to high productivity that creates enhanced preservation through the periodic cycling and scavenging of essential nutrients. Usually, a combination of these factors results in the accumulation of enough OM to produce these black shales. This research shows the relationships between trace metal data and the environment of deposition of several cores taken along the eastern side of the Cincinnati Arch in the central Appalachian Basin. Whereas the indices do not all agree in every instance across the breadth of the study area, analyzed together a predominant environment of deposition has been inferred for the shales. The Sunbury Shale and upper part of the Cleveland Member of the Ohio Shale were deposited under euxinic conditions, the lower part of the Cleveland Member was likely euxinic in the northern study region and anoxic throughout the central and southern study areas, whereas the Huron Member of the Ohio Shale was deposited under a range of conditions, from oxic, to dysoxic, to anoxic.

No description available.

For Sweden to achieve the environmental goal of a nontoxic environment, knowledge is required about harmful elements’ movement and mobility in nature. One of those elements is arsenic that for a long time has been known to cause health ailments. The most common and dangerous path into the human body is through drinking water. It is therefore of great importance to study sources that can impact and contribute to elevated concentrations of arsenic in the groundwater. One such path is the anthropogenic soil called rödfyr, which is what is left after the burning of black shale. This activity was common in areas rich in limestone, which after being heated can be used as cement in concrete. Heaps of rödfyr of varying sizes have been found at a number of localities in the area around Kinnekulle in Västergötland. Earlier studies of leach water indicate arsenic content high enough to be considered hazardous to health. At Kinne-Kleva south of Kinnekulle there is an unusually large heap of rödfyr, situated around land used for agricultural purposes as well as some houses. To have a good understanding about how rödfyr impacts the environment is key to predict and negate negative environmental consequences. The aim of this independent project is with fieldwork and leach tests study in which concentrations arsenic can be found in rödfyr at the Kinne-Kleva heap. Results show that high concentrations of arsenic exists, up to 137 mg/kg rödfyr. They also indicate that arsenic leakage occurs to a large extent, both in high and low pH environment. The amount of arsenic is however expected to be drastically reduced due to dilution, which increases with distance. Exposure is therefore confined to the close vicinity of the pile. / För att Sveriges miljömål om en giftfri miljö ska kunna uppnås krävs kunskap om skadliga ämnens rörelse och transport i naturen. Ett av de ämnena är arsenik, som sedan länge förknippats med nedsatt hälsa. Den vanligaste och farligaste vägen in i människokroppen är genom dricksvattnet. Därför är det av stor vikt att undersöka källor som kan påverka och tänkas bidra med förhöjda halter arsenik i grundvattnet..En sådan källa är den antropogena jordarten rödfyr, vilken är en restprodukt vid förbränningen av alunskiffer. Denna aktivitet var vanligt i områden rik på kalksten, som efter upphettning sedan kan nyttjas som cement i murbruk.I området kring Kinnekulle i Västergötland har rödfyr hittats på flera platser i varierande mängd. Tidigare undersökningar av lakvatten pekar på att halterna arsenik är så höga att långsiktigt intag kan anses hälsovådligt. I Kinne-Kleva söder om Kinnekulle finns en ovanligt stor rödfyrshög, belägen i ett område med åkermark och även några bostadshus. Att ha en god uppfattning om hur rödfyr påverkar sin omgivningen är av ytterst vikt för att förutsäga och hindra negativ miljöpåverkan.Syftet med detta kandidatarbete är att med platsbesök och laktester undersöka i vilka halter arsenik kan förekomma i lakvattnet vid rödfyrslokalen i Kinne-Kleva.Resultatet visar att rödfyren innehåller höga halter arsenik, uppemot 137 mg/kg. De visar också att läckage av arsenik förekommer i stor utsträckning, både under höga och låga pH. Halterna arsenik som lakas ut väntas dock minska kraftigt med avståndet från högen till följd av utspädning. Den främsta exponering föreligger således i högens närområde.

No description available.