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Howard A Armstrong - One of the best experts on this subject based on the ideXlab platform.
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Black Shale deposition in an upper ordovician silurian permanently stratified peri glacial basin southern jordan
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Howard A Armstrong, Brian R Turner, Issa M Makhlouf, Geoffrey D Abbott, Aminu Bayawa Muhammad, Nikolai Pedentchouk, Henning PetersAbstract:Abstract The Lower Palaeozoic (Upper Ordovician–Silurian) succession of North Africa contains one of the world's most prolific Black Shale source rocks, yet the origin of these rocks remains contentious. The Black Shale of the Batra Formation in Jordan was deposited at high palaeolatitude during rapid Hirnantian to early Silurian deglaciation. Here we report geological and organic geochemical results that provide evidence for an increase in photic zone primary productivity during ice melting. The decay of this organic matter through oxidative respiration resulted in euxinia, which enhanced the potential for organic matter preservation. The occurrence of isorenieratane in all samples indicates euxinia extended from the photic zone to the sediment water interface. The stratified basins and fjords of east Antarctica provide a likely modern analogue.
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origin sequence stratigraphy and depositional environment of an upper ordovician hirnantian deglacial Black Shale jordan
Palaeogeography Palaeoclimatology Palaeoecology, 2006Co-Authors: Howard A Armstrong, Brian R Turner, Issa M Makhlouf, Graham P Weedon, Ahmad Al Smadi, M. Williams, Abdulfattah Abu SalahAbstract:Abstract The upper Ordovician succession of Jordan was located ∼60°S, less than 100 km from the Hirnantian ice sheet margin. New graptolite dates indicate glaciation ended in Jordan in the late Hirnantian (persculptus Biozone). The succession records two glacial advances within the Ammar Formation and the subsequent deglaciations. Organic-rich Black Shales (Batra Formation) form part of the final deglacial transgressive succession that in-filled an existing low stand glacial continental shelf topography. The base of the Black Shale is coincident with the maximum flooding surface. During transgression, interfluves and sub-basin margins were breached and Black Shale deposition expanded rapidly across the region. The top of the Black Shales coincides with peak highstand. The “expanding puddle model” (sensu Wignall) for Black Shale deposition, adapted for the peri-glacial setting, provides the best explanation for this sequence of events. We propose a hypothesis in which anoxic conditions were initiated beneath the halocline in a salinity stratified water column; a fresher surface layer resulted from ice meltwater generated during early deglaciation. During the initial stages of marine incursion, nutrients in the monimolimnion were isolated from the euphotic zone by the halocline. Increasing total organic carbon (TOC) and δ13Corg up section indicates the organic carbon content of the Shales was controlled mainly by increasing bioproductivity in the mixolimnion (the Strakhov model). Mixolimnion nutrient levels were sustained by a continual and increasing supply of meltwater-derived nutrients, modulated by obliquity changes in high latitude insolation. Anoxia was sustained over tens to hundreds of thousands of years. The formation of Black Shales on the north Gondwana shelf was little different to those observed in modern Black Shale environments, suggesting that it was the nature of the Ordovician seas that pre-disposed them to anoxia.
Kentaro Izumi - One of the best experts on this subject based on the ideXlab platform.
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isotopic and mineralogical variations in the infill of chrondrites from organic rich Black Shale posidonia Shale germany for assessing the mode of colonization
Spanish Journal of Palaeontology, 2020Co-Authors: Kentaro IzumiAbstract:The compositional variations of the infill of Chondrites within the Toarcian (Lower Jurassic) organic-rich Black Shale of southern Germany were evaluated on the basis of organic carbon-isotope and XRD analyses of the infill, surrounding Black Shale, and overlying greenish-grey mudstone for assessing the mode of colonization by the trace-maker. Both carbon-isotope rations and the mineralogical compositions (i.e., quartz/calcite peak-height-ratio) of the infill show much larger variations than those of the overlying mudstone and ambient Black Shale. These limes of evidence strongly confirm the prolonged upward migration model, and the short-term opportunistic colonization model is not likely in this case. Although the obtained data cannot directly provide any evidence of the chemosymbiotic trace-maker model, this study also indicates that the isotopic and mineralogical variations recorded in the infill of Chondrites can be used as good indicators to assess the trace-maker’s colonization style, furthermore to distinguish opportunistic/climax trace fossil
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formation process of the trace fossil phymatoderma granulata in the lower jurassic Black Shale posidonia Shale southern germany and its paleoecological implications
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Kentaro IzumiAbstract:Abstract The ichnogenus Phymatoderma is a subhorizontal branching burrow system consisting of radiating tunnels filled with fecal pellets. This ichnogenus has been interpreted as a product of a deposit-feeding animal, but the question of whether the Phymatoderma-producer was a subsurface deposit feeder or a surface deposit feeder is still a topic of controversy. Herein I present evidence, based on carbon–isotope analyses, for the formation of the trace fossil Phymatoderma granulata occurring in the lower Toarcian Black Shale in southern Germany. Carbon–isotope ratios of organic carbon (δ13Corg) in the pelletal infill of P. granulata, the surrounding Black Shale, and the overlying gray mudstone are − 26.64 ± 0.42 (2σ) ‰, –28.49 ± 0.44 (2σ) ‰, and − 26.27 ± 0.13 (2σ) ‰, respectively. The difference between the pelletal infill and overlying mudstone in terms of δ13Corg is much smaller than that between the fillings and Black Shale; therefore, these data clearly indicate that the Phymatoderma-producer ingested the surface sediments and subsequently excreted fecal pellets into the subsurface sediments. Such a surface deposit-feeding style would be an especially effective means of absorbing nutrients, because surface sediments contain much fresh organic material, whereas organic matter in subsurface deposits consists mostly of refractory material that is poorly utilized by most marine benthos.
Robert B Perkins - One of the best experts on this subject based on the ideXlab platform.
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geogenic cadmium pollution and potential health risks with emphasis on Black Shale
Journal of Geochemical Exploration, 2017Co-Authors: Yizhang Liu, Tangfu Xiao, Robert B Perkins, Jianming Zhu, Zhengjie Zhu, Yan Xiong, Zengping NingAbstract:Abstract Cadmium (Cd) is a non-essential trace element that is toxic to humans. Previous studies of Cd in the environment have primarily focused on pollution resulted from anthropogenic sources, but little is known on naturally occurring sources of Cd. This paper aims to review the geochemical distribution of geogenic Cd and associated environmental risk. The source, accumulation, mobility, transportation, and health risk of Cd are discussed in a geo-environmental perspective, with an emphasis on Black Shale soils. Cadmium generally occurs in sulfides in Black Shale, and is easily released when exposed to oxygen and water. Leaching of these rocks tends to elevate Cd concentrations in aquatic systems, and may pose the potential to produce acid rock drainage (ARD) as well. Weathering of Cd-rich rocks also elevates soil Cd concentrations, and influence the geochemical species of Cd. Crops grown in these soils tend to accumulate higher Cd and threaten the food safety. Local inhabitant exposed to high geogenic Cd via food chains may experience Cd-related health risk. High Cd concentrations are observed in urine, and renal damage is also detected in Cd naturally enriched area based on low molecular weight proteins in urine. Overall, the findings in literature have provided with insights for potential health risk of Cd in areas with high Cd geochemical background levels, particular for the Black Shale exposed areas, more attentions should be paid on the geogenic Cd pollution, and suitable strategies of remediation and geo-environmental management for geogenic Cd pollution need further research.
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The relative mobility of trace elements from short-term weathering of a Black Shale
Applied Geochemistry, 2015Co-Authors: Robert B Perkins, Charles E. MasonAbstract:Abstract Black Shales contain high concentrations of trace elements, which may be liberated to the environment as a result of natural weathering and, potentially, during Shale gas development and future mining of Black Shales for extraction of Shale oil. The Sunbury Shale is one of the youngest units making up the thick Devonian and Mississippian Black Shale sequence in the Appalachian Basin. This study compares the trace element geochemistry of samples collected from two exposures of Sunbury Shale located
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a modern vs permian Black Shale the hydrography primary productivity and water column chemistry of deposition
Chemical Geology, 2004Co-Authors: David Z Piper, Robert B PerkinsAbstract:The sediment currently accumulating in the Cariaco Basin, on the continental shelf of Venezuela, has an elevated organic-carbon content of approximately 5%; is accumulating under O2-depleted bottom-water conditions (SO42− reduction); is composed dominantly of foraminiferal calcite, diatomaceous silica, clay, and silt; and is dark greenish gray in color. Upon lithification, it will become a Black Shale. Recent studies have established the hydrography of the basin and the level of primary productivity and bottom-water redox conditions. These properties are used to model accumulation rates of Cd, Cr, Cu, Mo, Ni, V, and Zn on the seafloor. The model rates agree closely with measured rates for the uppermost surface sediment. The model is applied to the Meade Peak Phosphatic Shale Member of the Phosphoria Formation, a phosphate deposit of Permian age in the northwest United States. It too has all of the requisite properties of a Black Shale. Although the deposit is a world-class phosphorite, it is composed mostly of phosphatic mudstone and siltstone, chert, limestone, and dolomite. It has organic-carbon concentrations of up to 15%, is strongly enriched in several trace elements above a terrigenous contribution and is Black. The trace-element accumulation defines a mean primary productivity in the photic zone of the Phosphoria Basin as moderate, at 500 g m−2 year−1 organic carbon, comparable to primary productivity in the Cariaco Basin. The source of nutrient-enriched water that was imported into the Phosphoria Basin, upwelled into the photic zone, and supported primary productivity was an O2 minimum zone of the open ocean. The depth range over which the water was imported would have been between approximately 100 and 600 m. The mean residence time of bottom water in the basin was approximately 4 years vs. 100 years in the Cariaco Basin. The bottom water was O2 depleted, but it was denitrifying, or NO3− reducing, rather than SO42− reducing.
Xin Liao - One of the best experts on this subject based on the ideXlab platform.
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Deterioration and Oxidation Characteristics of Black Shale under Immersion and Its Impact on the Strength of Concrete.
Materials (Basel Switzerland), 2020Co-Authors: Xin Liao, Sixiang Ling, Wenda Zhang, Jiannan Chen, Qingfeng Wang, Deping GuoAbstract:Black Shale, which usually contains pyrite, is easily oxidized and generates acid discharge. This acidic environment is not favorable for concrete in engineering applications and is likely to affect the durability of engineering structures. This study investigated the effect of acid discharge from the weathering of Black Shale on the strength of concrete under partially immersed conditions. Black Shale concrete immersion tests were conducted at different immersion depths to evaluate the oxidation conduction of Black Shale. Water chemistry and oxidation products were monitored during and after the immersion tests. The quality and strength of the Black Shale and concrete specimens were obtained before and after the immersion by testing the ultrasonic wave velocity and uniaxial compressive strength. The results indicated that a lower immersion depth of Black Shale reveals a higher degree of oxidation, and the capillary zone in Black Shale is critical for Black Shale oxidation in terms of mass transfer. The ultrasonic velocity of the concrete showed different change patterns in the immersed and non-immersed zones. Precipitation and additional hydration enhanced the quality and entirety of the concrete (increased ultrasonic velocity) at the non-immersed or partially-immersed zones, while the dissolution of concrete was dominant in the immersed zone (decreased ultrasonic velocity) and induced a reduction of concrete quality. The compressive strength of the concrete was enhanced after immersion. The concrete strength slightly increased by 5-15%. This phenomenon is attributed to the filling of the voids by the precipitations of minerals, such as goethite and anhydrite.
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Characteristics of interactions between Black Shale and water
E3S Web of Conferences, 2019Co-Authors: Xin Liao, Kangji Wang, Sixiang Ling, Deping GuoAbstract:Some geological engineering problems are caused by weathering of Black Shale within dispersed sulfide minerals (mainly pyrite), in which some weathering products such as acid water and expansive sulfates play an important role. These effects are essentially manifested through oxidation of sulfide minerals. Complex chemical reactions occur simultaneously and influence mutually in water-rock interaction process. Chemical weathering of Black Shale is a factor leading to engineering problems such as landslides and acid corrosion. The objectives of present study are to understand the process of water-rock interactions between Black Shale and water. The semi-immersion simulation experiment is mainly used to explore the chemical weathering characteristics of Black Shale under natural conditions.
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evolution of porosity and clay mineralogy associated with chemical weathering of Black Shale a case study of lower cambrian Black Shale in chongqing china
Journal of Geochemical Exploration, 2018Co-Authors: Siyuan Zhao, Sixiang Ling, Xin LiaoAbstract:Abstract This work aimed to evaluate the evolution of pore networks and clay mineral in Black Shale weathering systems in Chongqing, China. The pore-size distributions, relationships between fractal dimensions and minerals, and clay mineral weathering pathways were evaluated for three weathering profiles, A, B, and C, which were characterized as weak, weak to moderate, and moderate to intense based on the Chemical Index of Alteration. It was found as the Shale density decreased, the porosity and specific surface area increased with decreasing depth during weathering. The largest pore diameter peak in a pore-size distribution graph shifted further right as the degree of weathering increased. Micro-transition pores ( 1 μm) dominated the saprock and regolith zones. The surface fractal dimension of the micro-transition pores was positively correlated with the pyrite and carbonate content, but negatively correlated with secondary clay mineral content. By contrast, the surface fractal dimension of the macropores was negatively correlated with pyrite and carbonate content and positively correlated with secondary clay mineral content. These relationships indicate that micro-transition pores at the surface became smoother and macropores became rougher during weathering. Inherited micas, including illite, predominated the clay fractions along transects as weathering proceeded. The pedogenic minerals (i.e., smectite, vermiculite, kaolinite, and mixed-layer minerals) were minor components in the saprock and regolith zones. Smectite formation was likely due to direct transformation from mica or illite under strongly acidic conditions. A second possibility is transformation proceeded through mixed-layer mineral intermediates, i.e., mica-smectite/illite-smectite and mica-vermiculite/illite-vermiculite. The weathering of clay minerals in Black Shale from weak to intense weathering stages was mica/illite → mica-smectite/illite-smectite or mica-vermiculite/illite-vermiculite → “chlorite” (including vermiculite, hydroxy-interlayered vermiculite?, and chlorite?) → smectite → kaolinite → gibbsite. This study revealed pore geometry evolution depends on transport-limited solutions that facilitate mineral breakdown and formation. The clay mineral weathering pathways were controlled by the weathering environment and duration.
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investigation of water rock interactions in cambrian Black Shale via a flow through experiment
Applied Geochemistry, 2014Co-Authors: Xin Liao, Masahiro Chigira, Yuki MatsushiAbstract:Abstract This paper summarizes the results of a flow-through experiment of our own design intended to investigate the water–rock interactions between pyrite embedded in Black Shale and dissolved oxygen in pore water. Deionized water in equilibrium with 3 atm of PN2 or PO2 was flowed through a cylindrical rock specimen at 25 °C. The electrical conductivity (EC) and pH values of the experimental outflow solutions were continuously monitored. First, original pore water was expelled by N2-saturated water followed by O2-saturated water. Concentrations of major ion species were determined for solutions periodically withdrawn from the experimental system. The changes in these components over time indicated that 1. The chemical composition of the original pore water in the Black Shale was rich in hydrogen ions, sulfate ions and iron species and that 2. Two major reactions, namely, ion exchange and pyrite oxidation, occurred during the water flow. The oxidation of pyrite in Black Shale was controlled by the concentration of dissolved oxygen as FeS 2 + 7 / 2 O 2 ( aq ) + H 2 O → Fe 2 + + 2 SO 4 2 - + 2 H + , where the rate law for the reaction at pH = 4.2–5.6 and T = 25 °C was determined to be Rsp = 10−8.42±0.06 [O2]0.5 (mol m−2 s−1). This result is consistent with the reaction rate of pyrite grains with dissolved oxygen reported by previous researchers. Hydraulic conductivity decreased by approximately 12.5% during the nitrogen-inflow stage and by 69% during the oxygen-inflow stage. This change can be attributed to the oxidizing reaction within the rock and to the probable clogging of fine weathering products in the pore space. The geochemical modeling of the experimental outflowing water and seepage samples from the field using the PHREEQC program suggested that pore water develops into an acidic solution rich in iron and sulfate due to long-term pyrite oxidation and evaporation.
Aleksandra Sklodowska - One of the best experts on this subject based on the ideXlab platform.
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bioweathering of kupferschiefer Black Shale fore sudetic monocline sw poland by indigenous bacteria implication for dissolution and precipitation of minerals in deep underground mine
FEMS Microbiology Ecology, 2012Co-Authors: Renata Matlakowska, Aleksandra Sklodowska, Krzysztof NejbertAbstract:The Upper Permian polymetallic, organic-rich Kupferschiefer Black Shale in the Fore-Sudetic Monocline is acknowledged to be one of the largest Cu-Ag deposits in the world. Here we report the results of the first study of bioweathering of this sedimentary rock by indigenous heterotrophic bacteria. Experiments were performed under laboratory conditions, employing both petrological and microbiological methods, which permitted the monitoring and visualization of geomicrobiological processes. The results demonstrate that bacteria play a prominent role in the weathering of Black Shale and in the biogeochemical cycles of elements occurring in this rock. It was shown that bacteria directly interact with Black Shale organic matter to produce a widespread biofilm on the Kupferschiefer Shale surface. As a result of bacterial activity, the formation of pits, bioweathering of ore and rock-forming minerals, the mobilization of elements and secondary mineral precipitation were observed. The chemistry of the secondary minerals unequivocally demonstrates the mobilization of elements from minerals comprising Kupferschiefer. The redistribution of P, Al, Si, Ca, Mg, K, Fe, S, Cu and Pb was confirmed. The presence of bacterial outer membrane vesicles on the surface of Black Shale was observed for the first time. Biomineralization reactions occurred in both the membrane vesicles and the bacterial cells.
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biodegradation of kupferschiefer Black Shale organic matter fore sudetic monocline poland by indigenous microorganisms
Chemosphere, 2011Co-Authors: Renata Matlakowska, Aleksandra SklodowskaAbstract:This study provides the first evidence for the direct biodegradation of persistent organic matter extracted from the organic-rich polymetallic Black Shale ore Kupferschiefer, one of the most important sources of metals in the world. It was demonstrated that an enriched community of indigenous heterotrophic microorganisms isolated from Black Shale grown under aerobic conditions could utilize Shale organic matter as the sole carbon and energy source. Colonization of Shale organic matter was observed. The main biodegradation intermediates and products such as phosphonic acid dioctadecyl ester and isoindole-1,3 were detected in the aqueous phase of cultures. The bacterial community showed the ability to PAH biodegradation, assimilation of organic acids and esters as well as lipase activity. The intracellular accumulation of phosphorus by bacteria during growth on organic matter was confirmed. Strains within the genus Pseudomonas were found to dominate the bacterial population at the end of the experiment. The results of this study confirm that indigenous bacteria are likely to play a role in the biotransformation of Black Shale and can influence the geochemical cycles of ancient organic carbon in the deep terrestrial subsurface. This process may also occur in tailings ponds containing Black Shale, and cause the mobilization of potentially toxic compounds to the soil and groundwater.
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biotransformation of organic rich copper bearing Black Shale by indigenous microorganisms isolated from lubin copper mine poland
Environmental Science & Technology, 2010Co-Authors: Renata Matlakowska, Wanda Narkiewicz, Aleksandra SklodowskaAbstract:The role of indigenous microorganisms in the biotransformation of refractory organic-rich copper-bearing Black Shale ore (Kupferschiefer) was confirmed in laboratory experiments. The persistent sha...
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the culturable bacteria isolated from organic rich Black Shale potentially useful in biometallurgical procedures
Journal of Applied Microbiology, 2009Co-Authors: R Matlakowska, Aleksandra SklodowskaAbstract:Aims: The aim of this study was the isolation and characterization of micro-organisms from Lubin copper mine potentially useful in biotechnology of metal recovery from copper bearing Black Shale. Methods and Results: Eight bacterial strains were isolated from Black Shale ore. Phylogenetic analysis based on 16S rRNA gene homology showed that five strains belonged to the γ-Proteobacteria, one to the Firmicutes and two to the Actinobacteria. The ability of the isolates to transform bituminous Shale and use them as carbon and energy sources, as well as high resistance to metals and metalloids, esterase and lipase activities, assimilation of organic acids, degradation of phenanthrene and siderophores production were shown. Conclusions: The indigenous bacteria exhibited a broad range of physiological properties related to geochemical parameters of the examined environment and potentially useful in biometallurgical procedures. Significance and Impact of the Study: The results have yielded new insights into the microbiology of Black Shale. It can be suggested that isolated micro-organisms might play a role in the geochemical cycle of carbon and metals occurring in the organic fraction of Black Shale ore and might be of potential use in biotechnological procedures for the copper recovery and other valuable metals from tailings containing Black Shale as well as organic rich ore.