Black shales.

A recent drilling operation in the Triassic Yanchang Formation (Tongchuan District of the Ordos Basin, north-central China) reached a black shale bed with an average in-situ gas content of 1.11 g/ml. Subsequent total organic carbon (TOC) content measurements and rock-eval analysis showed that the black shale section was generally classified as excellent source rock, with TOC contents commonly ...Black shales <0.3 m below (samples 4, 5, Table 3) and <0.4 m above the sulfide ore bed (samples 9-12, Table 3) also display significantly higher concentrations of Mo (21-fold), Ni (12-fold), As (5-fold), Sb and Zn (3-fold), Co, Cu and P 2 O 5 (2-fold) than the average Cambrian black shale. Conversely, V and Mn values are comparable and the Cr ...Sep 30, 2015 · 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 Center 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 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 disappearMo enrichments and isotopic signatures in black shales from the main negative CIE also indicate globally extensive seafloor euxinia during this phase of the T-OAE, in excess of 10x that in the modern (Pearce et al., 2008), and potentially between 2-10% of global seafloor area (Dickson, 2017), though an increase in seawater Mo isotopes …

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 ).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 ...

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. Channel sample, 2 in. of black, very hard shale ...May 1, 2020 · 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. 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 ...shale definition: 1. a type of soft, grey rock, usually formed from clay that has become hard, that breaks easily…. Learn more.Using the modern Black Sea as an analogue, ancient black shales may record the Mo isotope composition of contemporaneous seawater if conversion of MoO 4 2− (molybdate) to MoS 4 2− (thiomolybdate) is quantitative in the overlying euxinic water column and pore water (Barling et al., 2001, Arnold et al., 2004, Neubert et al., 2008).

Each of the processes summarized above is capable of depositing organic-rich sediments or otherwise influencing black shale sedimentation. They may operate singly or together (Fig. 1).Process interaction can occur sequentially by means of flow transformation, as in a slide becoming a slump, then a debris flow, a high- to low-concentration turbidity current and finally, a hemiturbiditic plume.

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 ...

Maximum chloride concentrations are centered in the black shale sequences, decreasing above and below this unit, thus suggesting that the brines are sourced externally through the black shales. Unlike sites 1257 and 1259, site 1258 and 1260 pore waters are not characterized by the presence of brines ( Shipboard Scientific Party, 2004 ).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 …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 …Oct 14, 2010 · Black shales and massive sulfides represent reduced lithofacies that require isolation from oxic environments to be preserved. This, together with the sedimentary affinity of both lithofacies, can explain their common concurrence in the geologic record. The present study is based on the comparison of Rammelsberg in Germany, Tharsis in Spain, and Draa Sfar in Morocco, three massive sulfide ... 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 ...Jan 1, 2013 · 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 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 ...'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 ...Few black shales contain concentrations of precious metals higher than average continental crust (i.e. ∼5 ppb Au). Yet Au and Pt alloys have been reported from the Kupferschiefer in Poland. Moreover, thin sulfide beds in certain Chinese and Canadian shales contain several hundred ppb Au, Pd and Pt and average ∼4% Mo and ∼2.5% Ni in an ...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).Physical features of the Appalachian Plateau include coalfield sites, sandstone bluffs, sedimentary rocks and black shale. The Plateau is of great economic significance due to the coalfields in the area.First high-resolution δ<SUP>13</SUP>C-records across black shales of the Early Aptian Oceanic Anoxic Event 1a within the mid-latitudes of northwest Europe (Germany, Lower Saxony Basin)a

Molybdenum, Bi, and Te are commonly enriched along with Au, As, and Sb in organic matter and in diagenetic pyrite in black shales (e.g., Large et al. 2007Large et al. , 2011 Gregory et al. 2015 ...Jun 1, 2023 · 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).

limestones are enclosed within the black shales and nodular to bioturbated limestones occur between the marls [1,11,33]. Black Shale . The black shales, also known as dark, laminated shales [33], form thin (a few cm) to thick (up to 2 m) beds. They are blue-grey and fissile in weathered surfaces, but dark-grey to black and laminatedThe shale specimens were retrieved from an outcrop of Marcellus formation located in the western New York. Marcellus shale is an organic rich shale formation, extends in the subsurface from New York state in the north to the northeastern Kentucky and Tennessee in the south, eastern Ohio to extreme western Virginia.23 Marcellus shale primarily contains carbonaceous silty black shale with ...The black shales of the deeper sites correlate with pink to gray fissile marls in the shallowest section. In the two remaining sections, this stratigraphic interval is missing. A relative sea ...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 ...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 ...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). 2.2Black 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 ...Four black shale samples have TOC contents between 7.9% and 11.4% (Fig. 2b), while those of the other 19 black shales from well YK1 exceed 12%. The TOC contents of the studied black shale samples range between 12.1% and 29.9%, with an average of 18.2% (Table 1). In spite of the fact that the TOC is an important criterion for source

shale, any of a group of fine-grained, laminated sedimentary rocks consisting of silt- and clay-sized particles.Shale is the most abundant of the sedimentary rocks, accounting for roughly 70 percent of this rock type in the crust of the Earth.. Shales are often found with layers of sandstone or limestone.They typically form in environments where muds, silts, and other sediments were deposited ...

Bakken Formation black shales pinch-out landward via intra-shale onlap and stratal thinning; conversely, lower Virden black mudstone thins seaward via downlap and stratal thinning. Acknowledgments. The writer is grateful for helpful suggestions by two anonymous reviewers and editor Jim Schmitt. Special appreciation is expressed for the ...

Provided by the Springer Nature SharedIt content-sharing initiative. Shales that are rich in organic matter occur throughout the geologic record, but special conditions are responsible for their occurrence (Tourtelot, 1979). Before considering organic matter- and metal-rich shales, some background information is necessary.The black shales parent rocks have elevated Cd concentration and act as a source of Cd. The liberated Cd from black shales outcrop temporarily accumulated in the acidized surrounding soil and could arise potential adverse impacts on environment due to rainfall. Although high concentration of Cd was not detected in stream water, Cd concentrated ...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 ...Metallic minerals in black shale. In order to analyze the types of metallic minerals present in the lower Cambrian black shale, minerals from samples in the Xa1 and Xb1 wells have been preliminarily identified. The main sulfur-bearing mineral is pyrite that forms clumps and bands (Fig. 3).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).Black shales of the ca. 1.73 Ga Wollogorang Formation previously yielded an erroneously young Re-Os date of 1359 ± 150 Ma, likely due to post-depositional hydrothermal alteration at ca. 1640 Ma. Higher δ 238 U is observed in samples closer to the base of the black shale unit where the greatest extent of open-system Re-Os behavior was observed.Colour: Black, Grey Group: Clastic Sedimentary Rock Texture: Clastic; Very fine-grained (< 0.004 mm) Silty shale . Clay shale . Sandy shale Mineralogical …An early Cambrian black shale sequence found in several sites in South China is well known for containing various kinds of ores; for example, the nickel-molybdenum (Ni-Mo) polymetallic deposits of Hunan and Guizhou provinces (Fig. 1) (Chen et al., 1982, Fan et al., 1973, Fan et al., 1984, Fan et al., 2004, Zeng, 1998).These polymetallic deposits have been of research interest since their ...Dec 1, 2021 · An indicative classification of black shales can be compiled based on the literature that refers to the degree of commodity metal accumulation (Table 1).Vine and Tourtelot (1970) set the threshold of metalliferous black shales’ (MBS) definition above the 90th percentile of a metal concentration in given dataset, whereas the final classification depends on the frequency (percentage) of ...

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).Jun 15, 2011 · Two black shale areas, the Dongping and the Yanxi areas of the county, were selected for this study (Fig. 1). The black shales of both areas are organic-rich carbonaceous shales that host vanadium ores in Dongping area and uranium ores in Yanxi area. Soils developed on the black shales are typically yellowish. Few black shales contain concentrations of precious metals higher than average continental crust (i.e. ∼5 ppb Au). Yet Au and Pt alloys have been reported from the Kupferschiefer in Poland. Moreover, thin sulfide beds in certain Chinese and Canadian shales contain several hundred ppb Au, Pd and Pt and average ∼4% Mo and ∼2.5% Ni in an ...Instagram:https://instagram. scenic drives in kansashyunjoonku freshman move in 2022coldwell banker hot springs ar Black shale contains abundant pyrite and organic matter that are susceptible to weathering when exposed to the air. In the process of weathering, acid mine drainage can be produced, and a range of toxic trace elements including Cr can be released and transported into rivers, groundwater and soils, potentially leading to severe environmental pollution.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 ... mcoc champs to awakenku sororities Early Cambrian black shales in the South Qinling (SQL) of China constitute one of the world's most important vanadium- and barium-metallogenic belts. It is controversial on the enrichment mechanics of vanadium (V) and barium (Ba) mineralization. The V and Ba mineralization in the Xichuan area from the northern SQL is mainly hosted by shales and ... effective persuasion For the present study, black shale samples of the Doushantuo Formation at Jiulongwan and Baiguoyuan sections were collected (Fig. 1, Fig. 2).The stratigraphy and sedimentary structures of the two sections have been discussed in detail elsewhere (McFadden et al., 2008, Mi et al., 2010).Black shale samples were collected from the ∼12 m thick Member 4 at the Jiulongwan section, including 7 ...The black shale profile (PA and PB) were taken from the Shuishi Formation, which is mainly composed of gray to red sandstone-siltstone interbedded with argillaceous siltstone, sandy shale, black shale, and black shale-weathered products (Fig. 2). To avoid possible contamination of trace metal from falling materials from the upper horizons ...