Lower Silurian `hot shales' in North Africa and Arabia: regional distribution and depositional model

Lüning, Sebastian; Craig, Jonathan; Loydell, David K.; Štorch, Petr; Fitches, Bill

doi:10.1016/s0012-8252(99)00060-4

Cited by 440 publications

(246 citation statements)

References 111 publications

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“…The global sea-level fluctuations caused by growth and decay of Hirnantian icesheets are considered to have been an important influence on contemporaneous marine redox conditions (Lüning et al, 2000;Landing, 2011), although the exact nature of these effects has been debated. In most shallow-marine sections globally (i.e., shelf settings at water depths b 200 m), the onset of the Hirnantian glaciation was marked by enhanced oxygenation and its termination by a shift toward more reducing conditions (Yan et al, 2012;Zhang et al, 2011;Zhou et al, 2012).…”

Section: Hirnantian Glacio-eustasymentioning

confidence: 99%

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

Liu

Algeo

et al. 2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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The Ordovician-Silurian (O-S) transition coincided with significant environmental and biological changes. In South China, the Yangtze Platform experienced both global and regional events at this time, including sea-level fluctuations, tectonic movements, volcanic eruptions, mass extinction, and widespread anoxia. The O-S transitional strata of the Yangtze Platform comprise organic-rich black shales that are an important oil source rock. To explore the evolution of watermass chemistry and its relationship to organic matter accumulation, we conducted an integrated Fe-S-C geochemical study (i.e., Fe-speciation, δ 13 C org , δ 34 S py , pyrite-S and TOC) of the O-S boundary sections at Datianba (Chongqing Municipality) and Shuanghe (Sichuan Province). These sections were located in the restricted inner Yangtze Sea, in contrast to the previously studied Wangjiawan section, which was deposited in a more open setting of the outer Yangtze Sea. In contrast to the well-oxygenated conditions at Wangjiawan, the Datianba and Shuanghe sections record persistently anoxic, and episodically euxinic, conditions during the Hirnantian, which can be explained by the unique paleogeography and restricted hydrography of the inner Yangtze Sea. We propose that the regional Kwangsian Orogeny, which was driven by collision of the Yangtze and Cathaysia blocks, played a key role in basin development, watermass chemistry changes, and accumulation of Wufeng Formation black shales within the Yangtze Sea. The more widespread black shales of the Lower Silurian Lungmachi Formation were linked to the post-Hirnantian global marine transgression.

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Section: Hirnantian Glacio-eustasymentioning

confidence: 99%

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

Liu

Algeo

et al. 2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…It is thought that layers with higher amounts of organic carbon form during anoxic conditions and are the result of rapid early burial of organic matter. It is believed that most layers with a high organic carbon content form during transgressions (Lüning et al, 2000) and are related to transgressive systems tracts. However, there are suggestions that these organic rich layers can form during early regression phases of a sea level cycle as well (Loydell et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

The preservation of total organic carbon of the Silurian Pridoli strata in the Milaičiai-103 well core of Western Lithuania

Gelūnaitė¹,

Spiridonov²

2015

geol-geogr

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Augustė Gelūnaitė, Andrej Spiridonov. The preservation of total organic carbon of the Silurian Pridoli strata in the Milaičiai-103 well core of Western Lithuania. Geologija. Geografija. 2015. T. 1(2). ISSN 2351-7549.The Pridoli series is one of the thickest and most complete stratigraphic intervals of the Silurian as well as other systems of the Lithuanian part of the Baltic sedimentary basin. In this study we present a sequence stratigraphic model of the sedimentary succession in the Milaičiai-103 core section. High resolution trend of concentrations of total organic carbon is presented in the developed stratigraphic context. The variability in the total organic matter amount in different sequence stratigraphic system tracts was statistically evaluated using the generalized linear mixed-effect modeling approach. The statistical analysis revealed that the highest concentrations of total organic carbon in the studied section are expected in a highstand and transgressive system tracts and significantly lower concentrations are expected in a lowstand and falling stage system tracts.

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“…Silurian black shales deposited on the southern passive margin of the Rheic Ocean (North Africa and Middle East) consist of graptolitic shales with abundant organic matter related to blooms of marine prasinophytes (Tyson, 1994). The deposition of these shales took place during a high sea level stand in a mature ocean basin with wide shelves located at 45-55 • S under an upwelling zone (Parrish, 1982;Tissot et al, 1984;Klemme and Ulmishek, 1991;Lüning et al, 2000;Peters et al, 2005;Cramer and Saltzman, 2007). Late Devonian algal-rich black shales, which were deposited at high southern latitudes along the western margin of Gondwana (Brazil and Bolivia) under an upwelling zone, are a further example of black shale deposition on the margins of a mature ocean basin.…”

Section: Mature Ocean Basin and Closurementioning

confidence: 99%

Phanerozoic environments of black shale deposition and the Wilson Cycle

Trabucho‐Alexandre

Hay²,

Boer

2012

Solid Earth

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Abstract. The spatial and temporal distribution of black shales is related to the development of environments in which they accumulate and to a propitious combination of environmental variables. In recent years, much has been done to improve our understanding of the mechanisms behind the temporal distribution of black shales in the Phanerozoic and of the environmental variables that result in their deposition. However, the interpretation of ancient black shale depositional environments is dominated by an oversimplistic set of three depositional models that do not capture their complexity and dynamics. These three models, the restricted circulation, the (open) ocean oxygen minimum and the continental shelf models, are an oversimplification of the variety of black shale depositional environments that arise and coexist throughout the course of a basin's Wilson Cycle, i.e. the dynamic sequence of events and stages that characterise the evolution of an ocean basin, from the opening continental rift to the closing orogeny. We examine the spatial distribution of black shales in the context of the Wilson Cycle using examples from the Phanerozoic. It is shown that the geographical distribution of environments of black shale deposition and the position of black shales in the basin infill sequence strongly depend on basin evolution, which controls the development of sedimentary environments where black shales may be deposited. The nature of the black shales that are deposited, i.e. lithology and type of organic matter, also depends on basin evolution and palaeogeography. We propose that in studies of black shales more attention should be given to the sedimentary processes that have led to their formation and to the interpretation of their sedimentary environments.

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Lower Silurian `hot shales' in North Africa and Arabia: regional distribution and depositional model

Cited by 440 publications

References 111 publications

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

Global and regional controls on marine redox changes across the Ordovician-Silurian boundary in South China

The preservation of total organic carbon of the Silurian Pridoli strata in the Milaičiai-103 well core of Western Lithuania

Phanerozoic environments of black shale deposition and the Wilson Cycle

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