Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan

Armstrong, H. L.; Turner, Brian R.; Makhlouf, Issa M.; Weedon, Graham P.; Williams, Mark; Smadi, Ahmad Al; Salah, Abdulfattah Abu

doi:10.1016/j.palaeo.2005.01.007

Cited by 96 publications

(65 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7), which are predominately anoxic and generally contain high-TOC 'hot shales'. The MamuniyatTanezzuft interval in Jabal Eghei most probably straddles the interval temporally equivalent to the late Hirnantian and rhuddanian 'hot shale' interval in North Africa and Arabia (Armstrong et al 2005;Lüning et al 2005), even accounting for the expected c. 3 Ma diachroneity of the basal surface of the Tanezzuft Formation (e.g. Moreau 2011).…”

Section: Prolonged Glaciation and Delayed Anoxia In The Tanezzuft Formentioning

confidence: 97%

“…The overall relationship between ice extent, transgression and anoxia is in good agreement with the findings of some other studies on marine redox in this interval. Both Armstrong et al (2005) and Page et al (2007) observed that anoxia developed on maximum flooding surfaces allied to transgressions following Gondwanan glaciations. Although lingering ice sheets precluded the development of anoxia after the Hirnantian glacial maximum at Jabal Eghei, a brief interval of anoxia developed once they eventually decayed.…”

Section: Moderation Of Anoxia By Lingering Ice Sheetsmentioning

confidence: 99%

“…These include the 'hot shale' intervals of Aeronian-Telychian age in the NC174 concession, Murzuq Basin (Lüning et al 2000, p. 169) and the Telychian of the Tazzeka Massif, northern Morocco . The repeated intervals of 'hot shale' deposition may relate to glacioeustatically mediated oxic-anoxic cycles in the Late Ordovician-early Silurian (Page et al 2007), and although there is not yet a consensus on the cause of 'hot shale' deposition (see Armstrong et al 2005;Lüning et al , 2005, they appear to be a regional expression of globally extensive anoxic events.…”

Section: The Anatomy Of Toc Enrichment In the 'Hot Shale' Windowmentioning

confidence: 99%

“…Unfortunately, this model inadequately explains the sheet-like occurrence of organic-rich shales over wide areas of western Algeria, and a tectonic component for their uneven distribution has also been suggested around the oilfields of the northern Murzuq Basin . Elsewhere, in Jordan, variation in TOC is linked to changes in the rate of nutrients supplied to the upper ocean by deglacial outwash (Armstrong et al 2005(Armstrong et al , 2009). To better understand the controls on anoxia and the genesis of the 'hot shales', we address the temporal, lateral and bathymetric distribution of organic-rich shales and oxygen-poor depositional conditions from a superbly exposed succession in Libya.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Heron

Meinhold

Page

et al. 2013

JGS

View full text Add to dashboard Cite

Abstract:The Hirnantian glaciation of West Gondwana produced a glacially sculpted topography, which is draped by organic-rich latest Ordovician and early Silurian 'hot shales'. Although these are the most important Early Palaeozoic source rock in North Africa, organic enrichment is distributed unevenly. For example, in Al Kufrah Basin, Libya, 'hot shales' are elusive, but outcrop analysis at the western basin demonstrates why this is the case. The topmost Mamuniyat Formation, of Hirnantian age, comprises glaciogenic sandstones, passing upward into mixed facies of the Tanezzuft Formation, which has a latest Ordovician-early Silurian age. The basal Tanezzuft Formation contains a shelly carbonate (cool-water deposits accumulated under oxygenating conditions) and bioturbated sandstone succession. Above, hummocky cross-bedded and graded sandstone intervals are intercalated with shale and siltstone (storm influx onto a muddy shelf). These are interrupted by several lonestone-bearing intervals (ice-rafted debris), a striated pavement (of subglacial origin), and manganese oxide crusts and concretions. The concretions and bioturbation imply oxygenation of the sea floor during transgression. These putative glacial deposits were deposited following the main phase of the Hirnantian glaciation, at the same stratigraphic level as 'hot shales' elsewhere in northern Gondwana. Lingering ice caps may have produced well-oxygenated marine waters precluding 'hot shale' deposition.

show abstract

Section: Prolonged Glaciation and Delayed Anoxia In The Tanezzuft Formentioning

confidence: 97%

Section: Moderation Of Anoxia By Lingering Ice Sheetsmentioning

confidence: 99%

Section: The Anatomy Of Toc Enrichment In the 'Hot Shale' Windowmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Heron

Meinhold

Page

et al. 2013

JGS

View full text Add to dashboard Cite

show abstract

“…The distributive luvial systems (DFS) [35], which have been investigated in this book, are a particular type of luvial system, which is characterized by a downstream whose size decreases, is not bounded from valleys and shows a patern of diferent rays coming from an apex. The sequence stratigraphy of the ine-grained shales is an interesting research topic of this book, and theoretical aspects applied to several geological setings have been pointed out by several papers [36][37][38][39][40]. In particular, the sequence stratigraphy of the Barnet Shale and subordinately of the Woodford Shale is among the most studied research topics regarding the shales and has been coupled with other geological methodologies, including the geochemistry and the evaluation of the gas content for petroleum studies [41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Introductory Chapter: An Introduction to the Seismic and Sequence Stratigraphy and to the Integrated Stratigraphy: Concepts and Meanings

Aiello¹

2017

Seismic and Sequence Stratigraphy and Integrated Stratigraphy - New Insights and Contributions

View full text Add to dashboard Cite

The climatic significance of Late Ordovician‐early Silurian black shales

et al. 2017

View full text Add to dashboard Cite

The Ordovician‐Silurian transition (∼455–430 Ma) is characterized by repeated climatic perturbations, concomitant with major changes in the global oceanic redox state best exemplified by the periodic deposition of black shales. The relationship between the climatic evolution and the oceanic redox cycles, however, remains largely debated. Here using an ocean‐atmosphere general circulation model accounting for ocean biogeochemistry (MITgcm), we investigate the mechanisms responsible for the burial of organic carbon immediately before, during, and right after the latest Ordovician Hirnantian (445–444 Ma) glacial peak. Our results are compared with recent sedimentological and geochemical data. We show that the late Katian time slice (∼445 Ma), typified by the deposition of black shales at tropical latitudes, represents an unperturbed oceanic state, with regional organic carbon burial driven by the surface primary productivity. During the Hirnantian, our experiments predict a global oxygenation event, in agreement with the disappearance of the black shales in the sedimentary record. This suggests that deep‐water burial of organic matter may not be a tenable triggering factor for the positive carbon excursion reported at that time. Our simulations indicate that the perturbation of the ocean circulation induced by the release of freshwater, in the context of the post‐Hirnantian deglaciation, does not sustain over sufficiently long geological periods to cause the Rhuddanian (∼444 Ma) oceanic anoxic event. Input of nutrients to the ocean, through increased continental weathering and the leaching of newly exposed glaciogenic sediments, may instead constitute the dominant control on the spread of anoxia in the early Silurian.

show abstract

Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan

Cited by 96 publications

References 38 publications

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Did lingering ice sheets moderate anoxia in the Early Palaeozoic of Libya?

Introductory Chapter: An Introduction to the Seismic and Sequence Stratigraphy and to the Integrated Stratigraphy: Concepts and Meanings

The climatic significance of Late Ordovician‐early Silurian black shales

Contact Info

Product

Resources

About