Black shales

However, some black shales with high TOC contents show low concentrations of U (Lüning and Kolonic, 2003), probably a manifestation of the heterogeneity of sedimentary organic matter in organic-rich shales. How different macerals contribute to U content in the New Albany Shale is one of the key aspects of our study (Fig. 8).

The basal Member 1 is a cap carbonate with a thickness of approximately 1.5 m. Members 2 and 3 are mainly composed of carbonates and grey siltstones, with a thin layer of interbedded black shale (~2 m). About 9 m of an organic-rich black shale was developed in the uppermost Member 4 of the Doushantuo Formation (Fig. 1 c). 3. …Black shales are mixtures of terrigenous, biogenous, and hydrogenous sediment in which organic matter constitutes at least 0.5% of the material. Shales are the end product of the processes that ...Brown-black to green-black shales predominate throughout the Ohio/New Albany interval, interbedded with occasional thin beds of siltstone and silty shale. The Cleveland Member was subdivided into upper and lower segments for each core based on organic carbon content: the lower section consistently has a lower carbon content (less than 10% ...The black shale deposits, which are rich in Mo, Ni, V, and platinum group elements (PGE), are a reflection of that interval. Among all known Cambrian black shale deposits in South China, the ...In order to reconcile these conflicting results, four black shale samples, each between 10 and 20 cm long, were collected over a depth range of 98.3-141.25 m in ABDP core #3 (Hardey Formation) and five samples of black shale, each between 10 and 15 cm long, were collected over a range of depth of 85.2-267.81 m in ABDP core #6 (Table 1). 2.2Mudstone, sandstone, and carbonates are found in the Silurian–lower Devonian Dadas II and Dadas III members. Black to dark-gray, laminated pyrite-rich shales indicates the hot shale. Anoxic conditions existed in the depositional habitat, which was an open marine but temporally restricted [29]. 2.2. Tectonic features2.2.1.Jan 9, 2023 · The paleodepositional environments related to Ediacaran black shales from the Série Negra succession in Ossa-Morena tectonostratigraphic zone were investigated using their geochemical composition to identify the sedimentary sources and depositional conditions. Their potential for assisting the genesis of metal deposits was also discussed. The sedimentary sources of the black shales are ...

Organic matter (OM)-hosted pores are important constituents of the pore system of black shales and play a crucial role in determining their methane adsorption capacity and porosity. OM-hosted pores are generally observed and described with scanning electron microscope (SEM) on Ar ion-milled surfaces. However, SEM imaging is not able to reliably ...The black shales parent rocks have elevated Cd concentration and Cd would be released to the environment once black shales were exposed. The surrounding soil of black shales outcrop was highly acidized and enriched in Cd. Moreover, the surrounding soil could leach Cd and acid easily due to rainfall.Highly metalliferous black shales (HMBS) or hyper-enriched black shales (HEBS) contain >1500 ppm of combined Mo+Ni+Zn+Se+V (Johnson et al. 2017; Gadd et al. 2022). In addition to the metals ...Black shales may serve as an important source of metals such as Co, Ni, or As, largely due to anoxic to euxinic conditions in association with high concentrations of sulfur leading to efficient scavenging and transport of metals from seawater into the seafloor sediment. We report on an unusual type of Au mineralization newly discovered in Ediacaran trench-slope black shales in the Bohemian ...1. Introduction. Llandovery strata are widely distributed on the Yangtze Platform of South China. The lower part is dominated by graptolite-bearing shales, mudstones and siltstones, and was assigned to the Lungmachi Formation on the Upper and Middle Yangtze Platform (Fan et al., 2011).The Lungmachi Formation is composed generally of two parts, the lower part consisting of black shales and the ...Among these are black shales: fine-grained laminated sedimentary rocks rich in organic carbon (∼3% by weight or more) that also usually contain chemically distinct distributions of redox sensitive metals and sulfide minerals. When ancient sedimentary rocks rich in organic carbon are exposed on Earth's continents through uplift and erosion ...

When looked at more closely, the black shales have a laminated character (Fig. 3b) of the kind that one may see in many other laminated black shales in the rock record (O’Brien and Slatt 1990). These black shales showed discontinuous streaks of silt, and led to the term “silt-streaked black shales” when describing these rocks in drill core.Black shales intercalated with phosphorites of the Duwi Formation outcrop in the Qusseir-Safaga area, Red Sea coast (Fig. 1).Based on its lithology, Baioumy and Tada (2005) subdivided the Duwi Formation in the studied area into four members (Fig. 2).The lower member that ranges in thickness from 35 to 50 m is composed by yellowish-grey, laminated, silty claystone, greyish-yellow, laminated ...The basal unit of the Early Cambrian black shale sequence of South China hosts sulfide-rich polymetallic units, non-sulfidic vanadium-rich black shales, sapropelic alginite (combustible shale), barite, and phosphorite. This rock spectrum occurs in a paleoceanographic similar, and stratigraphically correlated, transgressive upwelling setting on the passive continental margin of the ...2001, Marine and Petroleum Geology. The ®rst important contention of this paper is that black shales can be deposited by any one or by a combination of the processes that typically control ®ne-grained sedimentation in deep water. These are brie¯y described below. See Full PDF.The 2.1 Ga old black shales of the Franceville Series, Republic of Gabon (Fig. 1) rank as one of the major Precambrian accumulations of organic matter.In size, the only closely comparable Proterozoic accumulation of organic matter is shungite from the Jatulian Series of Russian Karelia (see McKirdy and Imbus, 1992).In Gabon, uranium ores occur within quartzose sandstones at the top of the FA ...

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Black shales are sedimentary rocks containing >0.5% of organic carbon. They host polymetallic deposits which have been mined for Cu, Ni, Zn, Mn, P, Mo, V, U, …Black shales occur in a pivotal part of the classic Kansas cyclothem originally described by Moore (1936) and designated the core shale by Heckel (1977).The terminology differentiates this shale from other shales in the cyclothem, particularly the thicker nonmarine shales that separate the marine bundles of units that compose the majority of the cyclothems.Black shales are intercalated with phosphorites of the Duwi Formation in the Qusseir-Safaga area, on the Red Sea coast. The Duwi Formation overlies the fluvial shale series of the Qusseir Formation and underlies the deeper marine shales and marls of the Dakhla Formation (Fig. 1).Therefore, the Duwi Formation in Egypt represents the early period of the Late Cretaceous marine transgression.@article{osti_5841004, title = {Intergrated study of the Devonian-age black shales in eastern Ohio. Final report}, author = {Gray, J D and Struble, R A and Carlton, R W and Hodges, D A and Honeycutt, F M and Kingsbury, R H and Knapp, N F and Majchszak, F L and Stith, D A}, abstractNote = {This integrated study of the Devonian-age shales in eastern Ohio by the Ohio Department of Natural ...The dark shales in the Dongyuemiao member can be grouped into four general categories: shore, shallow, semi-deep, and deep lacustrine shales.Black shales were deposited in the continental margin rifts when the North China Craton underwent regional extension and break-up events during Mesoproterozoic era. The rock series, composed of clastic rocks, carbonate rocks, and minor volcanic rocks, are rich in gold, and become the source for gold mineralization.

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology ...The lower black shales exhibit much higher metal enrichments compared to Black Sea sulphidic (euxinic) sediment. This is taken to indicate the presence of sulphidic bottom waters during the deposition of the lower black shales, including the Ni–Mo ore layer. In contrast, anoxic, non-sulphidic conditions occurred during the deposition of the ...The Jurassic Da’anzhai Member in Sichuan Basin is an important target for shale oil exploration. Whole rock X-ray diffraction analysis, thin section, SEM and TOC testing, as well as major and trace element analysis are used to analyze the relationship of lithofacies and pore types with the sedimentary environment of the Da’anzhai Member in …Black shales are sedimentary rocks containing > 0.5% of organic carbon. They host polymetallic deposits which have been mined for Cu, Ni, Zn, Mn, P, Mo, V, U, Au and PGE (platinum group elements ...1. Introduction. Black shale (BS) is a dark-colored, usually thinly laminated and organic rich fine-grained rock with characteristics associated to specific sedimentology, paleoecology and geochemistry conditions formed within bottom water poor in oxygen (Wignall, 1994; Tyson, 2004).A wide range of sedimentary environments are favorable for the formation of BS and most ancient BS appear to ...Re-Os geochronology for black shales has been successful for documenting depositional ages and paleoenvironmental changes (Cohen and Coe, 2002, Hannah et al., 2004). New Re-Os isochron ages for stratigraphically well-constrained sedimentary rocks from Triassic sections in the Boreal realm are presented. The Ladinian-Carnian stage boundary ...The primary source of manganese to the Baltic Sea has been attributed (Suess, 1979) to input of terrestrially domi- nated organic matter. However, we have not found any mac- rofossils of terrestrial origin. Manganese-rich sediments are roughly 2 m thick and contain on average 2 to 5% manga- nese.Black shales are widespread at the Precambrian/Cambrian transition and document a global ocean anoxic event, which is part of major environmental and biological changes, such as plate tectonic reconfiguration, mass extinction, and accelerated diversification of metazoans (Kimura and Watanabe, 2001, Steiner et al., 2001).Weathered black shales and cherts show significant loss of Cr, and heavier Cr isotopes are released to weathering fluids, with isotope fractionations ranging up to 0.31‰. However, some weathered shales show enrichment of Cr with heavy isotopes, suggesting re-sequestration of mobilized Cr(VI) near redox-active zones (water table and …The Carboniferous (Namurian) Clare Shale Formation (Shannon Group) consists of finely laminated, pyritic, deep marine black shales, deposited 326.5–318.5 Ma (Menning et al., 2006; Wignall and Best, 2000).The black shale sequence is up to 180 m thick at surface, (Tanner et al., 2011), with a maximum observed thickness of 280 m in …Early Cambrian black shales on the Yangtze Platform host a regionally distributed highly metalliferous sulfide-rich carbonaceous unit which has been the subject of extensive debate. This marker unit, with a few centimeters or tens of centimeters in thickness, displays extreme enrichment in Mo and Ni (wt% range), and in a broad spectrum of other metals such as As, Au, PGE, Re, Cu, Zn, Cd, Ag ...

The Lungmachi black shales range in age from the Normalograptus persculptus Biozone of the uppermost Ordovician to the Spirograptus guerichi Biozone of the lower Telychian, and ten graptolite biozones can be recognized within this unit. The basal and upper contacts of the Lungmachi black shales are diachronous.

The black shales are usually enriched in metals (particularly zinc), but it is debatable as to which aspects of black shale geochemistry reflect depositional environment and sediment source, as distinct from overprinted patterns from diagenetic processes. However, redox-sensitive trace elements of V, Zn, Mo, and U seem to be robust measures of ...Black shales are a common lithofacies throughout the geologic record (Wignall, 1994). They consist of original muddy deposits rich in organic matter and sulfides. Black shales are favorable host rocks for many types of ore deposits (Grauch and Huyck, 1989, Starostin and Yapaskurt, 2007). Among them gold is very important, and many …Black shales in the Ediacaran Doushantuo Formation (predominantly from Member II, IV and equivalent strata) and the Lower Cambrian Niutitang Formation (or equivalents) occur widely in the Yangtze Platform, South China. These black shales could provide sufficient hydrocarbons for the petroleum system in this region. However, biomarker parameters have proven invalid in the assessment of ...The investigated Turonian aged black shale from the Cape Basin is a poor Type III/IV black shale. At DSDP sites 364 and 530A the Turonian to Coniacian black shales have a very good oil-prone marine source rock potential with high HI and TOC contents. The Organofacies trends correlate well with the evolution of the South Atlantic.The lacustrine black shales of the Lower Cretaceous Bayingebi Formation are an important hydrocarbon source rock in the Yin'e Basin. It is important to understand the mechanism of organic matter accumulation in these shales to reconstruct the palaeoenvironment and palaeoclimate in the Early Cretaceous in northwestern China and search for potential oil and gas resources.May 17, 2017 · Highly metalliferous black shales (HMBS) are enriched in organic carbon and a suite of metals, including Ni, Se, Mo, Ag, Au, Zn, Cu, Pb, V, As, Sb, Se, P, Cr, and U ± PGE, compared to common black shales, and are distributed at particular times through Earth history. They constitute an important future source of metals. HMBS are relatively thin units within thicker packages of regionally ... The lacustrine black shales in the Chang7 Member from the Upper Triassic Yanchang Formation of the Ordos Basin in Central China are considered one of the most important hydrocarbon source rocks. However, the mechanism of organic accumulation in the black shales remains controversial. To resolve the controversy, with the former paleontological data of Yanchang Formation and sedimentation rate ...The importance of black shales for scientists and the society are twofold. Black shales serve as source rocks for fossil fuels (oil and gas), which cover most of the energy needs of modern societies, and due to excellent preservation they provide particular sites for palaeontological studies.Black shales were mainly developed during the widespread transgression in the Early Cambrian. TOC contents also show that the black shales in the Xidashan, Xishanbrak, and Yuertusi formations are high-quality hydrocarbon source rocks, particularly those from the Yuertusi Formation. 5.2.1.1. Source rocks in the strata I region

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teristics of black shales deposited in those environments (Ta-ble 1). The resulting models represent a comprehensive and dynamic view of ancient environments of black shale accu-mulation; therefore, they are more useful in the interpretation of black shales than the existing three models in isolation. 2 Plate tectonics and exogenic processesMar 22, 2018 ... The black shales of the Wufeng and Longmaxi Formations are mainly composed of quartz, carbonates, clay, feldspar, and pyrite. The contents of ...Jan 25, 2019 ... Black shale in the Pennsylvanian of Kentucky, USA. Stratigraphy: lower tongue of the Breathitt Formation, Middle Pennsylvanian Locality: ...The overlying ∼2.6 Ga-Black Reef Formation separates the Ventersdorp Supergroup from the Chuniespoort Group, in the Transvaal Supergroup. The Chuniespoort Group hosts the Malmani Subgroup black shales that formed in a shallow seaway, constrained by detrital zircon U−Pb dating to an age of ∼2.588 ± 0.006–2.46 ± 0.005 Ga .During the Ordovician-Silurian transition, the Yangtze Block in South China experienced intense tectonic movements and climate change and was covered by the widely distributed black shales of the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation, which recorded key information about these major geological events. By geochemical and petrological analyses of three ...some of which are black shales, such as the Marcellus and Genesee. The stippled areas adjacent to the black shale outcrop in the east-central interior represent Lower Mis-sissippian strata. The positions of the Nashville and Lexington domes, portions of the Cincinnati arch, are clearly outlined by the black shale outcrops. The black shaleThe metals in black shales are mainly in the forms of sulfide and complex incorporated with organic matter (OM) (Nijenhuis et al., 1999, Brumsack, 2006). The sulfide minerals and OM in metalliferous shales tend to decompose under oxidizing conditions and break down at low pH due to the leaching of sulfide without the buffing material.@article{osti_5841004, title = {Intergrated study of the Devonian-age black shales in eastern Ohio. Final report}, author = {Gray, J D and Struble, R A and Carlton, R W and Hodges, D A and Honeycutt, F M and Kingsbury, R H and Knapp, N F and Majchszak, F L and Stith, D A}, abstractNote = {This integrated study of the Devonian-age shales in eastern Ohio by the Ohio Department of Natural ...Early models for Mid-Continent cyclothems placed the black shales in shallow water, with maximum transgression at the fusulinid-bearing zone in the overlying limestone. The most recent model proposed that the black phosphatic shales, which commonly occur between two subtidal carbonates, are widespread and laterally continuous over great ... ….

Black shale is commonly deposited in anoxic environments and hosts abundant organic matter, sulfides, and a variety of hazardous elements (Mao et al. 2002;Lehmann et al. 2007), resulting in its ...The paleodepositional environments related to Ediacaran black shales from the Série Negra succession in Ossa-Morena tectonostratigraphic zone were investigated using their geochemical composition to identify the sedimentary sources and depositional conditions. Their potential for assisting the genesis of metal deposits was also discussed. …A shale is a sedimentary rock that is composed of small (mostly less than 0.1 mm) particles dominated by phyllosilicate (clay) minerals and containing subordinate amounts of quartz, carbonate, and phosphate minerals and, in some cases, organic matter and pyrite [for a discussion, see Spears (1980)].Some shales are rich in unoxidized carbon. These are known as black shales, and some of them may also contain heavy metals like uranium, vanadium, zinc, …'Black shales' is an old term for argillaceous rocks rich in organic matter. The characteristics of the depositional environment of such deposits have long intrigued geologists, particularly the extent to which actualistic models can be applied. The revived interest in the last few years stems principally from the wide-spread recognition ...The black shale submember of core shales of Pennsylvanian Kansas-type cyclothems is highly enriched in redox-sensitive trace elements (TEs) relative to the overlying gray shale submember as well as to many other modern and ancient organic-rich deposits. Controls on trace-element behavior in the black shale can be inferred from trace-element ...Aug 14, 2023 · Locations of samples of black shales with critical mineral geochemistry (Granitto and others, 2017) were used as an evidential layer to calculate prospectivity models for sediment-hosted Pb-Zn mineralization as described in Lawley and others (2022). The Black-Shale Sea and its organic-rich muds were essentially the result of subsidence and sediment-starved conditions created by the collisional event which formed the Acadian Mountains. The interaction of these mountains with the atmospheric circulation patterns of the time is an important aspect of black-shale deposition.Black shales and thin-bedded cherts in the basal Cambrian are widespread worldwide and they carry important information on the formation of sedimentary basins and on the tectonic history. We studied the geochemical signatures of the early Cambrian black shales and bedded cherts from the Northern Tarim Basin, China, with the objectives of understanding the depositional setting of these rocks ...For American frackers that survive, a light is on the horizon. Chesapeake Energy Corp filed for bankruptcy on June 28, ending the pioneer’s run leading the US shale oil and gas industry. Founded in 1989, Chesapeake binged on debt to acquire... Black shales, [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1], [text-1-1]