BORON IN HOLOCENE ILLITES OF THE DOVEY ESTUARY, WALES, AND ITS RELATIONSHIP TO PALAEOSALINITY IN CYCLOTHEMS<sup>1</sup>

Adams, T. D.; Haynes, John R.; Walker, C. E.

doi:10.1111/j.1365-3091.1965.tb01288.x

Cited by 56 publications

(30 citation statements)

References 8 publications

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“…Kirsch and Stratmann (1959) consider most illites and mixed layer clays to be weathered derivative minerals which have been derived by potassium leaching, mainly from the alteration of initially sericitised feldspars. The distribution of illite and other clay micas is of interest because they may contain increased boron contents which is an indication of marine conditions of deposition (Degenes 1958;Adams et al 1965;Bohor and Gluskoter 1973;Swaine 1975). However, it should be noted that the illite associated with high rank coals is probably not of sedimentary but of diagenetic origin and mav have reolaced montmorillonite and kaolinite.…”

Section: Silicate Mineralsmentioning

confidence: 99%

Coal-Bearing Depositional Systems

Diessel¹

1992

399

416

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Section: Silicate Mineralsmentioning

confidence: 99%

Coal-Bearing Depositional Systems

Diessel¹

1992

399

416

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“…Previous studies show that paleosalinity could be quantitatively calculated by using boron and clays (Walker and Price 1963). Furthermore, the calculation accuracy of paleosalinity is enhanced by a new equation (Adams et al 1965;Couch 1971). A paleoredox condition can be reflected by redox-sensitive trace elements because their accumulation in sediments or sedimentary rocks is heavily influenced by conditions of redox in the paleoenvironment.…”

Section: Introductionmentioning

confidence: 99%

Impact of paleoenvironment, organic paleoproductivity, and clastic dilution on the formation of organic-rich shales: a case study about the Ordovician-Silurian black shales, southeastern Chongqing, South China

Tang

Zhang

et al. 2015

Arab J Geosci

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Three triggering factors, including preservation, organic paleoproductivity, and clastic dilution, for the formation of black shale successions during the Ordovician-Silurian transition have been debated for many years. Preserving conditions are controlled by redox conditions and microbial activities which have close relationship with salinity. Five outcrop sites of the Wufeng-Longmaxi black shales located in the southeastern area of Chongqing are analyzed for their elemental geochemistry, total organic carbon, and clay minerals. Clay minerals and boron are used to reconstruct the paleosalinity (S p ) of the bottom water during this period. Depending on the clay minerals' specific combining pattern, the calculation of S p is modified. The results show that the S p concentration ranges from 1.73 to 16.12‰, with an average value of 9.68‰. This shows an increasing trend from the Late Ordovician to the Early Silurian, indicating oligohaline-mesohaline water. Desalinization of the global ocean in the Late Ordovician was caused by melting of continental glaciers. The S p concentration shows negative correlation with total organic carbon (TOC) content, since the microbial decomposition rates are improved by high salinity. V/(V+Ni) and V/Cr ratios are used to reconstruct the paleoredox conditions of the bottom seawater during the Ordovician-Silurian transition, and the results suggest that the oxygen levels in seawater increased from the Late Ordovician to the Early Silurian and increased landward as a whole. Correlation between redox conditions with the TOC content reveals that anoxic conditions are favorable to the accumulation of organic matter. Ba and (Ba/Al) terr are used to calculate the biogenic Ba, in order to reconstruct organic paleoproductivity. The biogenic Ba shows no apparent relationship with the TOC content, which implies that organic paleoproductivity does not solely control the accumulation of organic matter. Si/Al and Ti/Al ratios are considered as indicators of clastic input. Our data imply that clastic input is quite low in the distal basin around the Ordovician-Silurian boundary, which is consistent with the maximum content of TOC. In the proximal basin, high clastic input dilutes enrichment of organic matter. We may conclude that complex, nonlinear interactions among the three factors most likely lead to the accumulation of organic matter. High preservation, low dilution, and low organic production lead to the formation of organic-rich shale, whereas low preservation, high dilution, and high organic production lead to organic-poor shale. Key PointsPaleoenvironment and organic paleoproductivity of the Yangtze Platform during the Late Ordovician and the Early Silurian are reconstructed.A combination of multiple factors significantly affects the formation of organic-rich shales.

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“…Some elements (e.g., Fe, Mn, V, Cr, Co, Sr, Ba, CaO, Mg, B, Rb, and Ni) and their ratios are always useful in various studies to decipher the paleosalinity, climate, and redox conditions during the depositions of sedimentary rocks in basin (e.g., Adams, Haynes, & Walker, ; Bai et al, ; Cao, Guo, et al, ; Couch, ; Hu, Li, Li, Huang, & Ge, ; Moradi, Sari, & Akkaya, ; Peng, Wang, & Jiang, ; Tanaka et al, ; Walker, ； Wu, Zhao, & Deng, ).…”

Section: Discussionmentioning

confidence: 99%

Geochemical characteristics, depositional environment, and provenance attitude of the Middle Jurassic Yangye Formation lacustrine mudstones in Kashi Sag, south‐western Tarim Basin

Wang

Zhu

et al. 2019

Geological Journal

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Middle Jurassic mudstones from the Yangye Formation are widely exposed in the Kashi Sag and regarded as significant potential source rocks. Geochemical characteristics of mudstones in the Keziletao Depression have been analysed to decipher their source‐area weathering, provenance, tectonic setting, and depositional environment that have received significantly little attention. Mudstones are characterized by high Ca, U, Th, and REE contents when compared to those of PAAS. Their total REE abundances range from 155.2 to 234.2 ppm, with the enrichment of LREEs and distinct negative Eu anomalies, implying a principal felsic provenance. Various indicators (e.g., CIA, Th/Sc, ICV, and Rb/Sr) and A‐CN‐K ternary diagram suggest parental rocks experienced a moderate to intense chemical weathering degree and simple recycling and sorting. Furthermore, paleoenvironmental indexes (e.g., B, “S,” Sr/Ba, “C,” Sr/Cu, and V/(V + Ni)) indicate that they were likely deposited in a suboxic to anoxic freshwater setting, with semi‐arid to semi‐humid paleoclimatic conditions during the deposition of Yangye Formation. The geochemical data also demonstrate that the provenances were derived predominantly from the unroofing of felsic rocks with a minor intermediate supply. These parental rocks were commonly formed in the continental island arc, active continental margin, and/or collision tectonic settings. The results of this study, combined with published data, suggest the West Kunlun Orogen and thrusting zone to the west and south‐west of the basin were probably arrested to provide substantial detritus for sediments, stimulating a better understanding for the formation mechanism of the Yangye Formation sediments (especially for potential source rocks) in the Kashi Sag.

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BORON IN HOLOCENE ILLITES OF THE DOVEY ESTUARY, WALES, AND ITS RELATIONSHIP TO PALAEOSALINITY IN CYCLOTHEMS¹

Cited by 56 publications

References 8 publications

Coal-Bearing Depositional Systems

Coal-Bearing Depositional Systems

Impact of paleoenvironment, organic paleoproductivity, and clastic dilution on the formation of organic-rich shales: a case study about the Ordovician-Silurian black shales, southeastern Chongqing, South China

Geochemical characteristics, depositional environment, and provenance attitude of the Middle Jurassic Yangye Formation lacustrine mudstones in Kashi Sag, south‐western Tarim Basin

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BORON IN HOLOCENE ILLITES OF THE DOVEY ESTUARY, WALES, AND ITS RELATIONSHIP TO PALAEOSALINITY IN CYCLOTHEMS1

Cited by 56 publications

References 8 publications

Coal-Bearing Depositional Systems

Coal-Bearing Depositional Systems

Impact of paleoenvironment, organic paleoproductivity, and clastic dilution on the formation of organic-rich shales: a case study about the Ordovician-Silurian black shales, southeastern Chongqing, South China

Geochemical characteristics, depositional environment, and provenance attitude of the Middle Jurassic Yangye Formation lacustrine mudstones in Kashi Sag, south‐western Tarim Basin

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BORON IN HOLOCENE ILLITES OF THE DOVEY ESTUARY, WALES, AND ITS RELATIONSHIP TO PALAEOSALINITY IN CYCLOTHEMS¹