Black shales. limestones are enclosed within the black shales and nodular to bio...

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Apr 28, 2019 ... Summary The origin of organic carbon-rich (black) shales is commonly attributed to changes in oceanographic conditions such as anoxia or ...In this study, Late Neoproterozoic black shales from South China were analysed using slice experiments and ultra-clean organic geochemical laboratory techniques with two main aims. Hydrocarbons were analysed firstly so as to explore the hidden information of ancient ecosystems during a key transition time of Earth, and secondly so …Abstract. Black shale is a dark-colored mudrock containing organic matter that may have generated hydrocarbons in the subsurface or that may yield hydrocarbons by pyrolysis. …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 microscopy), and X-ray diffraction analysis to ...Phanerozoic black shales. Black shales may be deposited during most stages of the Wilson Cycle, but the depositional environment and partly also the type of black shale (Fig. 2) depend, for each basin, on the Wilson Cycle stage. Simi-larly, black shales were deposited throughout the Phanero-zoic, but periods of relatively widespread …The black shales below and above show relatively lower Fe T /Al ratios, reflecting the same range as sediments from the Black Sea, which is the largest modern anoxic ocean basin (Severmann et al., 2008). Table 1.The geochemistry of major and trace elements (including heavy metals and rare earth elements) of the fresh and weathered black shales, and the soils derived from black shales in the Ganziping mine area in western Hunan province (China) were studied using the following techniques: X-ray fluorescence (XRF), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray diffraction (XRD). The ...Black shale, variety of shale that contains abundant organic matter, pyrite, and sometimes carbonate nodules or layers and, in some locations, concentrations of …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)].The black-shale intervals lack bioturbation and feature mm-thick sub-layers of varying dark-grey and sometimes grey-green colour (in web version). Occasionally, small 1–2 cm thick limestone layers are intercalated (e.g., in couplet 2). The prominent black-shale intervals in couplets 7 and 9 lack limy sub-layers.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 ...The Fe enrichment of Nkporo shale is relatively similar to Oshosun Gery and Black Shales (Ajayi et al. 2006) but the K and Na enrichments vary in the shale samples. The Fe mean value of Ekenkpon Shale is slightly higher than Nkporo Shale, while the K and Na mean values are relatively similar (Table 5 and Fig. 6 ).The black shales that host the Mn ore layers are well laminated, black siliceous mudstone with intercalations of gray calcareous mudstone (Fig. 4 a). The black siliceous mudstone laminae are organic-rich and consist dominantly of fine-grained siliciclastic materials (e.g., quartz, feldspar, and clay minerals), as well as pyrite with …Six black shales are identified in total: note the sharp base and top of black shale 4. The sharp definition of the shale indicates a primary depositional origin and hence rapid switching between anoxic and more oxygenated conditions at or near the sea floor. B: Single vertical burrow crosscutting laminated grey shale and reaching 1 m in length ...In this study, uniaxial compressive strength (UCS) tests together with an acoustic emission (AE) system and SEM and EDS analysis were performed to investigate the mechanical properties and microstructural changes of black shales with different saturation times (10 days, 20 days and 30 days) in water dissoluted with gaseous/super-critical CO₂.Black shale is composed of quartz (50%), calcite (10%), kaolinite (25%) and montmorillonite (15%). Organic and inorganic analyses revealed that this shale was deposited under oxic to anoxic marine ...China's most successful horizon for shale-gas exploration and development is the Upper Ordovician Wufeng Formation through the Lower Silurian Longmaxi Formation in its Upper Yangtze Region. In this study, the Wufeng-Longmaxi Formation black shales in the Upper Yangtze Region are analysed to determine their microstructural characteristics, total organic carbon (TOC) content, and well log ...The black shale sequence of the Niutitang Formation is enriched in a broad spectrum of redox-sensitive trace elements, i.e., Mo, Ni, Zn, Cr, V, PGE, Au, and U, typical of black shales in general (Holland, 1979, Ketris and Yudovich, 2009, Vine and Tourtelot, 1970).Significantly, an unusual polymetallic Ni–Mo–PGE–Au sulfide ore layer enriched in …Apr 18, 2016 · 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 . Black shales are sedimentary rocks with a high content of organic carbon, which leads to a dark grayish to black color. Because of their potential to contain oil or gas, black shales are of great ...Black shale is a dark-colored mudrock containing organic matter that may have generated hydrocarbons in the subsurface or that may yield hydrocarbons by pyrolysis. Many black shale units are enriched in metals severalfold above expected amounts in ordinary shale. Some black shale units have served as host rocks for syngenetic metal deposits.Black shales have formed throughout the Earth's ...The black shales in the Qusseir area (Duwi Formation, Campanian–Maastrichtian) were deposited in an anoxic marine environment, and are remarkably high in their enrichment of redox-sensitive and sulfide-forming trace metals. Measurements of Mn, U, V, and Mo reveal that the studied black shales deposited under shallow anoxic-sulfidic conditions.Environmental impact of mineralised black shales. Earth-Science Reviews 192, 65−90. View in Article CrossRef Google Scholar [4] Wignall, P. B. (1994). Black Shales (Oxford University Press). View in Article Google Scholar [5] Zhang, X.-L. (2022). Marine refractory dissolved organic carbon and transgressive black shales.Most recently, Kennedy et al. (2002), based on a study of two black shale locations of Cretaceous age, suggested that organic carbon (C org) absorption onto clay mineral surfaces is a major controlling factor in its burial and preservation. Peucker-Ehrenbrink and Hannigan (2000) and Jaffe et al. (2002) investigated mobility of platinum …Black shale, channel sample 0.4 ft thick. Black shale, channel sample 0.5 ft thick. Black shale, channel sample 0.4 ft thick. Do. Black shale, channel sample 1.4 ft thick. Phosphatic nodules, weathered; from whole exposure. Channel sample, 1 ft of black brittle shale; location in formation unknown; near base of about 15 ft expo­ sure.The lower Cambrian black shales in South China offer favorable conditions for analyzing the geochemical cycle of trace elements in an anoxic stratified paleo-ocean. The bulk-rock geochemical data are conducive to reconstructing unique environmental constraints during the early Cambrian. Here, the main purpose of this study is to analyze the ...The black shales of the Río Mayer Formation contain information that corresponds to the entire Lower Cretaceous of the Austral Basin. During this period, major tectonic changes occurred at the southern hemisphere, including the break-up of Gondwana and the initial opening of the Weddell Sea and the Atlantic Ocean ( i.e., Dalziel et al., 1974 ...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 ...Metalliferous black shales contain twice the amount (>1,000 ppm) of transition metals compared to the U.S. Geological Survey black shale standard SDO -1 (Huyck 1990;Kane et al. 1990).The Taiyuan formation, which consists of black shale, coal, limestone and sandstone, was deposited in this environment during the early Permian, with a thickness ranging from 30 to 175 m. Second, the collision between the North China plate and the Siberia plate caused large-scale tectonic movement and a marine regression from north to south.A suite of black shales interbedded with thin-bedded cherts occurs at the basal Cambrian in the Northern Tarim Basin (Fig. 2), which is called black rock series in Chinese literature (Li and Gao, 1996a, Li and Gao, 1996b, Li and Gao, 2000).The two studied sections are located at Xiaoerbulake, approximately 60 km away from the Akesu City, and at Sugaitebulake, approximately 50 km away from ...Highlights REE in organic matter in early Cambrian Niutitang Formation black shales from Zunyi, South China displays shale-normalized pattern unlike those of modern seawater, but with evident negative Ce anomalies, reflecting the oxic environment of surface productivity rather than the more reducing environment of bottom waters. Redox-sensitive trace element contents of U, V, and Mo in early ...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 ...Mo contents and isotopic compositions of the black shales were determined by the double-spike method. Mo was separated and purified by ion-exchange chromatography using BPHA resin, and analyzed by MC-ICP-MS (Thermo-Fisher Scientific Neptune Plus).Black shale. A dark, thinly laminated carbonaceous shale, exceptionally rich in organic matter (5% or more carbon content) and sulfide (esp. iron sulfide, usually pyrite), and often containing unusual concentrations of certain trace elements (U, V, Cu, Ni). Alabama - Arizona - Illinois - Indiana - Kentucky - Massachusetts - Maryland - Maine ...The results show that in addition to the ca. 1,380 Ma LIP activity that is coeval with black shales, other major LIPs during this period can preliminarily be divided into several stages and are ...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 ...Abstract. Ordovician black shales have been investigated extensively for at least three basic reasons: (1) they bear one of the system's most useful biostratigraphic tools, graptolites; (2) many ...To test whether there is a positive relation between MSA and TOC in black shales, we sampled an organic-poor to organic-rich (0.5 to 13% TOC) interval through the Cretaceous (Campanian) upper Niobrara Formation and lower Pierre Shale and analyzed the stratigraphic trends in TOC, MSA, elemental composition, and clay mineralogy in …Black shales are organic-rich, fine-grained strata deposited under oxygen-poor bottom waters which typically accumulate in deep-water, basinal locations (Demaison and Moore, 1980, Wignall and Maynard, 1993). However, thin examples often occur in more marginal locations, particularly within transgressive sedimentary records.In Guizhou and Hunan provinces, the lowermost few meters of the Niutitang Formation usually consist of stratiform cherts, nodular and bedded phosphorites and phosphate nodule-bearing black shales, an Ni-Mo sulfide horizon, and organic carbon-rich black shales (Fig. 2 A, B, C).The black shale in the lower part of the Niutitang Formation displays a higher TOC content (up to 15 wt.%) than the ...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 in Ukraine - A review. Reinhard Sachsenhofer Yurij Koltun. 2012, Marine and Petroleum Geology. The territory of Ukraine is located mainly within the southwestern part of the East European Craton (EEC) represented by the Ukrainian Shield . Paleozoic sedimentary basins formed along the margins and within the EEC during Paleozoic ...The paleoenvironment during the Early Cambrian is closely related to the accumulation mechanism of organic matter (OM) from the Lower Cambrian black shales. However, paleoenvironment remains a controversial issue. Here, we reported a lot of detailed data of sedimentary stratigraphy and geochemistry of the Lower Cambrian Yuertusi Formation in the Aksu area, Tarim Basin. The Yuertusi Formation ...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 ...Identification of black shale-hosted critical element deposits in the U.S. (initial focus on the Heath Formation metalliferous oil shales in Montana); and; Evaluation of processes that form metal-enriched black shale deposits. Return to Mineral Resources Program | Geology, Geophysics, and Geochemistry Science CenterThe 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 shale in Niutitang Formation of the Lower Cambrian widely develops in Guizhou Province, and its distribution is controlled by the type of the lithofacies palaeogeography. The black shale ...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 ...Black shales are dark, as a result of being especially rich in unoxidized carbon. Common in some Paleozoic and Mesozoic strata, black shales were deposited in anoxic, reducing environments, such as in stagnant water columns. Some black shales contain abundant heavy metals such as molybdenum, uranium, vanadium, and zinc. The Triassic black shale sequence of Kasımlar Formation in the Anamas - Akseki. Platform, Western Taurids, Turkey do not show any trace element enrichment. But ...Black shales may have been deposited in comparatively shallow water, within wave base of strong storms (Schieber, 1994, 1998a) in the vicinity of the Cincinnati Arch, as well as in the deeper water of basins adjacent to the Cincinnati Arch (Illinois and Appalachian Basins). Sequences may diminish in thickness or disappearBlack shale samples in the Guryongsan and the Changri Formations were taken from available outcrops in the Dukpyung and the Chubu areas (Fig. 1).Rock samples were crushed to −10 mesh (< 2 mm) in a jaw crusher, quartered, pulverized in a porcelain mortar to −200 mesh (< 80 μm), rehomogenized, and repackaged in sealed plastic bags.Surface soil samples (0-15 cm depth) including mountain ...The widespread, yet under-utilized, unfossiliferous Devonian black shales may hold the key to test this hypothesis by filling temporal and spatial gaps in the global path of afforestation and ...Nov 13, 2017 · Summary. 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 shale source rocks can also host oil and gas forming unconventional reservoirs. Therefore, a distinctly light Li isotopic composition of pore fluids, suggesting influx of hydrocarbon-sourced Li, may be useful in identifying productive intervals of a shale. We studied several well-known hydrocarbon source rocks to compare the Li isotopic ...Cretaceous black shales from the Cenomanian/Turonian Boundary Event (CTBE or OAE 2) are characterized by the enrichment of specific trace metals, in particular Ag, Cd, Mo, Zn, V, Cu, Ni, and others. Under present day oceanographic conditions many of these metals are involved in nutrient-type regeneration processes. For this reason elements like ...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).Classic black shales such as those from Chongqing, China (Conclusion. 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.T he black shales of the Xiaowa Formation, Guanling area, Guizhou Province, south-west China, are a unique Late Triassic (Carnian) Lagerstätte (Wang X. et al., 2000b, 2002a, b, 2003a, b).Nowhere else are so many marine reptile skeletons and pelagic crinoids known in such perfect preservation from this time. Comparable preservation and abundance is known only from the Anisian/Ladinian (Middle ...Mar 18, 2022 ... The black color is possibly introduced in these shales because of organic matter incorporated in the sediments. Hence, these shales tentatively ...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 widespread at the Precambrian/CambriThe black shales parent rocks have elevated Cd conce Black shale sequences were deposited at numerous locations now found in North America, northwestern Europe, and southern China during the Katian Age (456-445 Ma) of the Late Ordovician Epoch. The sequences were deposited in tropical settings that included carbonate banks and foreland basins [e.g., Young et al., 2008; Pancost et al., 2013a]. Oct 14, 2010 · Black shales and massive sulfides represent Colour: Black, Grey Group: Clastic Sedimentary Rock Texture: Clastic; Very fine-grained (< 0.004 mm) Silty shale . Clay shale . Sandy shale Mineralogical … The specific surface area and pore volume of OM in black...

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