Black shales.

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 ...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 ...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. Jul 21, 2015 · a) A black shale formed during OAE 1a (120 million years ago) cropping out at Permanente quarry, California, U.S.A. b) Livello Bonarelli black shale formed during OAE 2 (94 million years ago ... The oil shale is located in a single calcareous layer 2.5 to 3 metres (8.2 to 9.8 ft) in thickness and is buried at depths from 7 to 100 metres (23 to 328 ft). [6] The total area of the basin is about 3,000 square kilometres (1,200 sq mi). [1] Oil yield from Kukersite is 30 to 47%.

The term "black shale" is a common expression widely used to describe any dark~olored, fine-grained sedimentary rock relatively rich in organic matter. As defined by Weissert (1981), the range of organic carbon in black shales is between 1 and 30%, but values outside this range exist. The termWhen is a metalliferous black shale not a black shale?, by Holly L.O. Huyck 42 Recent Black Sea sediments-Leg 4, 1988 Black Sea Expedition, by Timothy W. Lyons 57 Organic geochemical studies of metalliferous parts of the Middle Proterozoic Nonesuch Formation of northern Michigan, by Philip A. Meyers, Eileen S. Ho, and Jeffrey L. Mauk 59that cut down into the underlying black shales (Schieber, 1998a). Contacts between pyrite ooid beds and underlying black shales are sharp, and multiple scour surfaces within py-rite ooid beds indicate a prolonged history of high-energy reworking and winnowing. The strong grain-size contrast between black shale and pyrite ooid beds (coarse sand ...

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 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.

The majority of black shale samples in the Dongyuemiao member show a positive correlation between porosity and T max when the T max ranges from ∼440°C to ∼465°C. This correlation consists of the tendency of Posidonia Shale (Type II) ( Han et al., 2017 ) and seems to suggest the thermally driven pore generation, e.g., the secondary OM pore.When black shales are weighted by preserved thickness, a time series (Isley and Abbott, 1999) shows three peaks in the Paleoproterozoic (i.e. ∼2.0, 1.85, and 1.7 Ga), with small peaks at 600 Ma and 1.45 Ga, ̄ and a maximum near the Archean/Proterozoic boundary between 2.7 and 2.5 Ga (Fig. 2).Plotted as a time series weighted by errors in …The black shales and sulfide layers, with the exception of replicate anal- yses of N21, lie on or between these reference lines, suggesting that, to a first approximation, the Re and Os were added close to the time of deposition. Regression of the data, how- ever, yields an errorchron with a negative '"Os/'^Os inter- cept. One replicate ...The Conacian Agwu shale overlies the Eze-Aku shale and is composed of black shale with minor intercalations of limestone and sandstone. Overlying the Agwu Formation is the Campanian to Maastrichtian Enugu/Nkporo Formation consisting mostly of shale, limestone and sandstone. The Imo Formation which is the youngest is found in the Tertiary Niger ...

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 ...

Shale is a sedimentary rock while slate is a metamorphic rock formed from shale. Slate is much more durable than shale due to the metamorphic process it undergoes. Slate and shale are similar in appearance. Visually, it can be hard to tell ...

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 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 ...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 ...In the outer Lesser Himalaya, black shales are present in the Infra-Krol, Krol, and Tal formations extending from Solan in the Himachal Himalaya to Nainital in the Kumaun Himalaya (Fig. 1). Black shales associated with the Infra-Krol and Upper Krol formations occur in and around Solan, Mussoorie, Garhwal, and Nainital (Fig. 1).The presence of Ediacaran fossils and stromatolites, chert, quartz ...Besides black shales, this paper also provides the first in-depth study of the geochemistry of phosphatic nodules (hosted by the black shales) that will allow primary and secondary processes to be understood. Geochemical investigations, particularly redox-sensitive trace element ratios (for e.g. V/(V + Ni) > 0.5; Ni/Co = 4.3–7.2; V/Cr > 2 and ...The black shale samples analyzed in this study originate from marginal marine sediments deposited from ∼2.66-2.084 Ga. South African samples cover a drill core depth of 85-2,440 m, with ages constrained to ∼2.66-2.32 Ga. The oldest originate from the Bothaville Formation, a part of the protobasinal rocks of the Ventersdorp Supergroup. ...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 Xiaotan section, situated on the southwestern Yangtze Platform, South China, contains an unusually expanded sedimentary record, spanning the upper Neoproterozoic to the Cambrian and representing more than 40 My of marine sedimentation.Three distinct black shale units of the Shiyantou and Yuanshan formations were analysed for redox-sensitive trace elements and iron speciation, in order to ...Fragments below exposure of fissile Marcellus black shale at Marcellus, N.Y. The Marcellus consists predominantly of black shale and a few limestone beds and concentrations of iron pyrite (Fe S 2) and siderite (FeCO 3). Like most shales, it tends to split easily along the bedding plane, a property known as fissility. The hydrocarbon potential of the black shale units has been evaluated by Rock-Eval pyrolysis. Total organic carbon content of many of the shales exceeds 1%. The meanT max for the black shales translate to a vitrinite reflectance range of 2.05-2.40% Rm based on standard conversion techniques. These shales have reached the catagenetic stage near ...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 Provisionally defined as shales containing metals exceeding those of average black shale by more than an order of magnitude, HBS underlie >200,000 sq. km. of the American Midwest (Fig. 1).The Niutitang Formation and equivalent strata of black shales overlie the Dengying Formation with a low-angle unconformity. The Niutitang Formation is dominated by black shales but its lower part has a very variable lithology with important sedimentary phosphorite and barite units, and up to several tens of meters thick “stone coal” …

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 ...

Devonian black shales deposited on the North American craton contain abundant Tasmanites cysts. Although these are typically flattened because of compaction, a small proportion are filled with diagenetic silica. The latter are spherical to ellipsoidal (0.1--0.5 mm), and filled with chalcedony, microquartz and megaquartz, and single quartz ...In order to constrain the evolution of the atmosphere, oceans, biosphere, and geochemical cycles of elements, a systematic and multidisciplinary study of inorganic geochemistry and stable isotope geochemistry was conducted using Archean- Paleoproterozoic black shales, graywackes, and red shales.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 ...Jan 30, 2018 · 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. The black shale samples analyzed in this study originate from marginal marine sediments deposited from ∼2.66-2.084 Ga. South African samples cover a drill core depth of 85-2,440 m, with ages constrained to ∼2.66-2.32 Ga. The oldest originate from the Bothaville Formation, a part of the protobasinal rocks of the Ventersdorp Supergroup. ...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 ...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). 2.2

Con il termine inglese black shale o semplicemente shale si identifica una roccia sedimentaria a composizione argillosa e con tessitura scistosa.

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 large and ...

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.Black shales occur widely in the Lower Cambrian and Neoproterozoic strata on the Yangtze Platform, South China. In this study, Lower Cambrian black shales from Xiuning section and Late Neoproterozoic black shales from Weng'an section were studied and Pb isotopic compositions were analyzed following a stepwise acid-leaching technique. The 206 Pb/ 204 Pb ratios in both sections show large ...New and existing Mo isotope data from early Cambrian black shales in South China span a range of greater than 3‰, which can only be explained by multi-stage fractionation of Mo isotopes. The ...Lower Paleozoic black shales from Estonia, Sweden, and Russia were analyzed for major and trace elements to reconstruct the provenance, tectonic setting, and paleoweathering conditions of these …General overview of black shales Six Desmoinesian organic-rich marine black shales members — Anna Shale, Turner Mine Shale, Excello Shale, Mecca Quarry Shale, Carrier Mills Shale and Veale Shale — were the main targets of this study (Fig. 2). They each produce a high response on gamma-ray logs, have high organic matter content, and have largeThe uranium (U) content, and more recently, the ratio between 238 U and 235 U in black shales are commonly applied as a proxy to determine redox conditions and infer organic-richness. Uranium contents typically display a linear relationship with total organic carbon (TOC) in shales. This relationship is due to the processes and mechanisms responsible for the incorporation of U into the ...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).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 …Black shale Clarke values are the average trace element contents in the World black shales. It is well known that black shales (carbonaceous, mainly marine sedimentary rocks) often are metalliferous and/or bituminous: enriched in U, V, Mo, Re, many other trace elements, and "shale oil". That is why the Clarke values for black shale are very ...

Uncover the black box of black shales Xingliang Zhang 1 , , 1. State Key Laboratory of Continental Dynamics, Shaanxi Key laboratory of Early Life and Environments, …Aug 22, 2023 · Shales that are rich in organic matter (>5%) are known as black shales. Black color is given to these rocks by organic matter. Organic matter should be decomposed in normal conditions by bacteria, but high productivity, rapid deposition and burial or lack of oxygen may preserve it. Pyrite is a common sulfide Dec 31, 2020 ... Composition, stratigraphic and structural position of Jurassic-Lower Cretaceous radiolarian-rich siliceous rocks and black shales are ...Instagram:https://instagram. scholarships for ku studentsnissan leaf carvanaelijah johnson kucraigslist ocean view de 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 … emily stockmanhy vee special 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 …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 processes gwendolyn mumma landes In order to constrain the evolution of the atmosphere, oceans, biosphere, and geochemical cycles of elements, a systematic and multidisciplinary study of inorganic geochemistry and stable isotope geochemistry was conducted using Archean- Paleoproterozoic black shales, graywackes, and red shales.uraniferous black shales; in some black shales, phosphatic nodules and layers with 0.02 to 0.1 percent uranium contain much of the uranium in the shale, but in other uraniferous black shales the nodules contain only 0.001 to 0.003 percent uranium. The biogenic phosphate that settles into a rela­