Black shales

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 Mamfe basin hosting the studied shales lies on basement rocks of the Precambrian age constituting of granite, syenites, gneisses, and mica-schists [12], [59].The sedimentary cover is mainly composed of variable black shales [6], [23].The shales are dark grey to black in colour deposited in a shallow lacustrine, oxygenated depositional environment [6].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 …May 1, 2019 · Abstract. 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). Even sub-economic occurrences provide potential risk of acid rock drainage when exposed to oxic surface environment. The black shales are composed of quartz, illite, kaolinite and traces of pyrite in some samples. Al 2 O 3 /TiO 2 ratios in the coals (6-62) and black shales (16-34) suggest a mixture of felsic and intermediate igneous rocks as sources for their detrital fractions, which is supported by the Zr-Ti binary plot.Early Cambrian black shales are widely distributed on the southeastern margin of the Yangtze platform, South China (Guo et al., 2007; Wen et al., 2015; Fig. 1).They formed under a variety of physicochemical conditions due to variable contributions of continental and biotic components with increasing water and burial depth, and they have …Chemical and isotopic signatures for black shales serve as potential proxies for reconstruction of paleoenvironmental conditions. Here we bring Rock‐Eval, major and trace element and Re‐Os isotopic data together to examine the environmental record at the Cambrian‐Ordovician Global Stratotype Section and Point (GSSP) at Green Point in western Newfoundland, Canada. The Green Point shales ...

The deposition of finely disseminated gold in the deposits hosted in black shales is considered. It is suggested that gold deposition is controlled by microstructure of pore space in host rocks. The pore space structure of tight shales indicates that most pore volume is occupied by nanopores with hundredths of micrometers in characteristic dimension. The balance calculations show that ...Black shale and coal Clarke values are the average trace element contents in the World black shales and coals. These calculations are made in Russian geochemistry but up to now are poorly known in ...The black shale horizons are several meters to several tens of meters thick and are strongly deformed due to their low competence relative to the host graywackes. In some places, the black shales enclose graywacke clasts and, vice versa, are found as angular to subangular clasts within graywackes (Hajná et al., 2013). 3. The Liblín section3.1.Furthermore, it is known that colour of black shale develops mainly due to the high concentration of carbonaceous matter deposited in reducing environment (Tourtelot 1979). In general, the black shale contains more than 1% of organic carbon (2-10% is the common range) (Tourtelot 1979). The shale samples collected from Dhonsa and Kodki are ...Black shales are currently of interest in geochemical and geological investigations because they may host gold and platinum deposits or petroleum and natural gas fields. To ensure the accuracy of analysis of such samples, standard reference materials SCHS-1 and SLg-1 are now being certified at the Institute of Geochemistry SB RAS, …Deposition of the black shales (total organic carbon [TOC] contents up to ∼9%; Crick et al., 1988, Jackson and Raiswell, 1991, Warren et al., 1998, Mukherjee and Large, 2016) likely occurred in a quiet-water distal shelf environment (Abbott and Sweet, 2000).The formation has similar organic geochemistry as the pre-Ediacaran biomarker assemblage facies 1 of Pawlowska et al. (2013), with high ...

Following Ireviken black shale deposition, conditions once again became oxygen deficient with the development of a euxinic zone in the water column. The Aeronian to Sheinwoodian deep-water redox history was unstable, and rapid fluctuations of the chemocline across the L/W Series boundary probably contributed to the Ireviken Event extinctions ...Introduction. Metalliferous black shales are organic-rich rocks that are commonly enriched in metallic elements localized in specific horizons. For example, in South China, the Lower Cambrian black shales sequence of the Niutitang Formation was deposited over several thousands of kilometers 9 (Fan et al., 1973, Zhang, 1987, Zeng, 1998).The Lower Cambrian black shales of the Sansui vanadium deposits, located in South China, host a thin accumulation of Ni, Mo, V, and platinum group of elements (PGE). However, among them, the origin of V-bearing deposits remains controversial. To characterize the enrichment process of V-bearing deposits, samples of the mineralized layer and surrounding rocks from the Sansui area, South China ...Devonian Black Shales Eastern USChattanooga, New Albany, Ohio Shales. The Mid-Late Devonian black shales of the Appalachian, Illinois, and Michigan Basins have long been studied to provide clues to past climates, ocean ventilation, mass extinctions, and general earth history. Common misconceptions about these shales are that they represent ...High thermal maturities raise questions about gas storage potential in lower Paleozoic shales. Given these uncertainties, a new look at Sichuan Basin shale gas ...

Event accessibility checklist.

DST black shales display slight enrichment of Mo (2.0–6.8 ppm; average = 4.2 ppm; n = 7), suggesting deposition under anoxic bottom conditions. Moreover, the patterns of Mo-TOC co-variation can provide valuable information about paleohydrographic conditions, especially the degree of watermass restriction, but only under anoxic …Jul 7, 2015 · Black shale, the subject of this article, is a dark-colored muddy sedimentary rock that is substantially enriched in organic matter. Depending on the grade of thermal maturity, black shales are often referred to as sapropel, bituminous shale, or oil shale. For example, the basal Irati black shales (AMa 1 and 5) from Amaral Machado (northeastern Paraná Basin) were deposited in a shallow marine environment with reducing and hypersaline conditions whereas most of the younger sediments have stored organic signals of deposition at greater water depth and lower salinity (Martins et al., 2020a, b). A ...1. Introduction. Due to the great commercial success of shale gas exploration and development in and around the Sichuan Basin, the geological characterization of over mature marine shale gas systems in South China has become a research focus (Jia et al., 2014; Tan et al., 2014a, Tan et al., 2014b, Tan et al., 2015; Li et al., 2015a, 2019).The pore structure of organic-rich shales not only ...

This study involves a comprehensive and detailed lithological, sedimentalogical, structural and geochemical description of the lower Ecca Group in the Eastern Cape, South Africa. The Ecca group hosts a ~ 245 million year old organic-rich black shale, which has recently been the focus of interest of petroleum companies worldwide. The shale was deposited under anoxic conditions in a setting ...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 distinguish OM types and relate the observed ...Lacustrine black shales are widely developed within the Late Cretaceous Nenjiang Formation (k 2 n) of the Songliao Basin. These black shales provide an ideal natural laboratory for reconstructing the paleoclimate and paleoenvironment during the Late Cretaceous in Northeast China and have great significance in the exploration for potential oil and gas resources.Shale gas refers to natural gas that typically accumulates in an adsorbed or unbound state, which is mainly found in black shale or carbonaceous shale (Curtis 2002; Chen et al. 2003; Zhang et al. 2003, 2004, 2007; Li et al. 2007).The shale gas in North America is developing very rapidly with the breakthrough of horizontal wells and the …Dunkirk black shale extends from Van Buren Point, on Lake Erie, to Holland, [western New York], where it is over 160 feet thick. Two characteristic (and unlike) septarian zones divide it into three members, throughout this distance, the upper of which was included by Luther in his overlying Portland shales. Included in Chemung group.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. Methods3.1.Introduction. The deposition of black shales and the accumulation of organic matter in black shales not only involves the basic biogeochemical processes on Earth, including photosynthesis, oxidation, bacterial sulfate reduction and humification, etc., but also makes an important contribution to the primary source of hydrocarbons and other economic mineral deposits (Arthur and Sageman, 1994 ...In black shales that have been heated to only 200-300°C, MoS 2 sheets have been found intercalated with graphite sheets in minute particles (the combination is designated MoSC; Kao et al., 2001 ...The Paleoproterozoic black shales of the Dhalbhum Formation exposed to the north of the Dalma metavolcanic suite is comprised of siliciclastic rocks and a minor amount of carbonaceous rocks. Geochemical studies were carried out to study the provenance and depositional setting of black shales. The average values of Co, V, U, and Cr/V (1.29) and Ni/Co (2.77) ratios in the black shales of ...Extensive deposits of marine black shales containing 2-30% TOC were episodically deposited over 100 million years of Mesozoic time (Toarcian through Coniacian epochs), but the most widespread occurrences are found in the middle Cretaceous (Arthur and Sageman, 1994).The periods of widespread deposition of the apparently synchronous black shale sequences (Table 1) that occurred during ...The Datangpo Formation can be sub-divided into four lithostratigraphic members from bottom to top (Fig. 2): (1) Member I is a succession of black manganiferous shale and Mn carbonates (Mn contents distinguish manganiferous shales with Mn < 10 % from Mn carbonates with Mn > 10 %); (2) Member II is composed mainly of black carbonaceous shale; (3 ...

Black shales have been of increasing interest in recent years due to their oil and gas potential, but also because many are enriched in nonfuel "unconventional" …

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 the 'Doonbeg No 1' drill hole, Co Clare (Goodhue and ...Two immature black shales from the Mesoproterozoic Xiamaling Formation, Xiajiagou outcrop, Zhangjiakou, Hebei Province, China, two immature black shales from the Cambrian Alum Shale Formation, Degerhamn, Öland island, Sweden, and a carboniferous low rank coal with VR o of 0.56% (sample ID ZJJ-C4) were collected for this study (Table 1).These black shales are not only rich in organic matter, but also undergone an unexpectedly low thermal evolution process, both of which contribute to well-preserved indigenous hydrocarbons and promote the convincing discovery of the Precambrian biology. The combination of the absence or low concentrations of gammacerane, dibenzothiophene series ...shale definition: 1. a type of soft, grey rock, usually formed from clay that has become hard, that breaks easily…. Learn more.Depositional and diagenetic processes play important roles in controlling the fabric and petrophysical properties of black shales.In this study, an outcrop section of the Wufeng-Longmaxi Shale was studied through sedimentologic facies analysis, petrographic observations (both transmitted- and reflected-light microscopy and scanning electron …In addition, black shales also have “stone coal” layers, huge phosphorous nodules and “rock coal” strata, and the phosphorus-containing nodules that are widely deposited on the passive continental margin of the early Cambrian Yangtze carbonate platform in South China metal sulfide layers are comparable (Lehmann et al., 2007).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 ...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 ...Ettensohn and coworkers have proposed more or less persistent and widespread anoxia during accumulation of much of the black shale succession (Ettensohn et al., 1979, Ettensohn and Barron, 1981, Ettensohn, 1985a, Ettensohn, 1985b, Ettensohn, 1998).According to Ettensohn's (1998) model, the extensive black-shale basins formed in response to foreland basin subsidence associated with the Acadian ...Shale, a brownish black to black hard fissile bituminous shale about 350 feet thick. In certain zones, numerous anthraconite concretions occur ranging in size up to three or more feet in diameter. Smaller marcasite concretions from the size of walnuts to a foot across are also present but in less abundance.

Landgrid free.

How to cite patents.

Black shales can record Earth's oxygenation process, provide petroleum and metallic mineral resources, and reveal information about the driver, direction, and magnitude of climate change. Future research on black shales should be expanded to encompass a more extensive and more multi-dimensional perspective.MARINE BLACK SHALES: Depositional Mechanisms and Environments of Ancient Deposits. Annual Review of Earth and Planetary Sciences ... Rodinia (1,100–750 Ma) and Pannotia (600–550 Ma). The Pan-African (600 Ma) and Grenville (1,100 Ma) collision zones are shaded pink. Abbreviations: CC, ... Figure 10: Late Precambrian and Early Ordovician ...The Ohio Shale Group of the Appalachian Basin hosts natural gas deposits that are sourced from several organic-rich members, including the Cleveland Shale (e.g. Ettensohn, 1987; Pashin and Ettensohn, 1995). The Cleveland Shale is a Late Devonian-aged black to dark gray shale which contains minor carbonate concretions and pyrite (Robl et al., 1983).In black shales of the Touirist Formation diahopane/hopane ratios conspicuously increase with core depth (Table 3); however, maturity can be excluded as a major control of the observed distribution, since all samples exhibit similar R c values (∼0.5-0.6; Table 4).Shale is mostly made up of clay, so it can range in color from medium brown to white. Shale is often used to make ceramic tiles. Shale colors fall in the neutral color palette and can be paired with blues for a country look, soft pinks for ...Black shales deposited in transitional environments such as tidal and deltaic environments have high terrigenous OM input. The pore structure characteristics of bulk OM in these transitional shales should have intermediate values between oil-prone OM (Fig. 19) in shales and terrigenous OM in coals at a specific maturity. Therefore, the ...The weathering profile is located at the Dongping town, Anhua County of Hunan province, centrally in the South-China black shale horizon (SBH, Fig. 1 a), which outcrops discontinuously along the southern margin of the Yangtze platform, throughout six provinces, in a belt approximately 1600 km long (Fan et al., 1973, Horan et al., 1994).The …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 ...The decay of 187 Re to 187 Os provides a tool for determining depositional ages of black shales. Re and Os concentrations and Os isotopic compositions of whole rock samples of the Bakken Shale, a Mississippian/Devonian boundary black shale, yield a whole rock isochron with an age of 354 ± 49 Ma. This age is in agreement with the accepted age ...Black shales are of great ecological significance due to the high concentration of heavy metals that are released during weathering. Heavy metals constitute one of the most insidious and dangerous pollutions known to humans (Akpan and others 2002) because they are toxic (e.g. carcinogenic), non-biodegradable, and may enter the global ecobiological cycle (Nurnberg 1984; Lakhan and others 2002). ….

The Ohio Shale is subdivided into seven recognizable units: Cleveland Shale, Three Lick Bed, Upper, Middle, and Lower Huron, Olentangy, and Rhinestreet. The Olentangy and Rhinestreet black shales correspond to the Java Formation of West Virginia, and thin and pinch out westward. A summary of reservoir data for the Big Sandy GasThe black organic-rich shales mainly developed in Quse and Sewa Formations. The Biluo Co (or Bilong Co or Bilong Cuo) area, about 45 km from the Shuanghu special district ( Fig. 1 b), is located in the southern Qiangtang depression (northern Tibet, China) and cropped out brown to dark, well-laminated shale horizons with a few intercalated ...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 ...Early Cambrian (Tommotian) black shales in South China contain submarine-hydrothermal exhalative sulfide ore layers within an arc-parallel linear belt extending more than 1600. km. Evidence for an Early Cambrian hydrothermal venting is given by the records of main and trace elements, rare earth elements (REE), sulfur …U.S. Department of Energy Office of Scientific and Technical Information. Search terms: Advanced search options. ...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 …If black shales similarly desorb methane in the presence of CO{sub 2}, the shales may be an excellent sink for CO{sub 2} with the added benefit of serving to enhance natural gas production. The concept that black, organic-rich Devonian shales could serve as a significant geologic sink for CO{sub 2} is the subject this research.Abstract. 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). Even sub-economic occurrences provide potential risk of acid rock drainage when exposed to oxic surface environment.Black Shales are fine grained, generally organic carbon-rich sedimentary rocks that primarily consist of a mixture of clay minerals, quartz silt, organic particles (mostly planktonic algae and plant debris), and kerogen. They may also contain variable amounts of disseminated finely crystalline calcite and dolomite, as well as phosphate ... The Global Geochemical Database for Critical Metals in Black Shales (CMIBS) contains new geochemical data compilations for fine-grained sedimentary rocks in which each geologic material sample has one 'best value' determination for each analyzed species, greatly improving speed and efficiency of use (Granitto and others, 2013). 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]