Contrasting watermass conditions during deposition of the Whitby Mudstone (Lower Jurassic) and Kimmeridge Clay (Upper Jurassic) formations, UK

Sælen, Gunnar; Tyson, Richard V.; Telnæs, N.; Talbot, Michael R.

doi:10.1016/s0031-0182(00)00150-4

Cited by 93 publications

(97 citation statements)

References 79 publications

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“…Figure S7). On the other hand, compound-specific carbon-isotope analysis on long-chain n-alkanes, sourced from terrestrial higher-plant leaf waxes or freshwater algae, also shows a 3-4‰ negative excursion, similar in magnitude to that observed in the bulk δ 13 C TOC record of the same core and coeval marine successions [85][86][87] . Aquatic and terrestrial organic matter (e.g.…”

Section: [223] Palynostratigraphymentioning

confidence: 57%

“…Figure S8. Comparison of the δ 13 C TOC , δ 13 C compound-specific and HI records from Yorkshire, Dotternhausen, Denkingen and the Sichuan Basin [85][86][87]89 , showing elevated HI values in all marine and lacustrine records, in concert with the T-OAE negative CIEs of ~4-7‰ in δ 13 C TOC record and of ~3-4‰ in δ 13 C compound-specific records. Figure S9.…”

Section: [223] Palynostratigraphymentioning

confidence: 97%

“…Figure S9. The cross-plot relationships between bulk organic δ 13 C and Hydrogen Index (HI) from Yorkshire, Dotternhausen, Denkingen and the Sichuan Basin [85][86][87]89 , showing correlations between bulk-organic δ 13 C and Hydrogen Index for all the marine and lacustrine records during the T-OAE negative CIE intervals with, however, a varying magnitude of correlation between different geological settings.…”

Section: [223] Palynostratigraphymentioning

confidence: 99%

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Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

et al. 2017

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(2017) 'Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event.', Nature geoscience., 16 (2). pp. 129-134. Further information on publisher's website:https://doi.org/10.1038/ngeo2871Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The early Toarcian Oceanic Anoxic Event (T-OAE at ~183 Ma) is recognized as one 32 of the most intense and geographically extensive events of oceanic redox change and 33 accompanying organic-carbon burial in the Mesozoic Era 1,2 . The T-OAE is marked by 34 major changes in global geochemical cycles, with an apparently rapid negative shift 35 of as much as ~7‰ in bulk marine and terrestrial organic-carbon isotope records and 36 a typically smaller (3-6‰) negative excursion in carbonate archives and specific 37 organic compounds 3-10 . The observed early Toarcian perturbation to the exogenic 38 carbon cycle has been linked to volcanism of the Karoo-Ferrar large igneous province 39 (LIP) and associated release of volcanogenic CO 2 , thermogenic methane (CH 4 ) from 40 sill intrusion into Gondwanan coals, and biogenic methane from dissociation of sub-41 seafloor clathrates 3,6,[11][12][13] . Early Toarcian elevated atmospheric pCO 2 likely induced 42 climatic and environmental change 5,12,[14][15][16] by accelerating the global hydrological 43 cycle and increasing silicate weathering, thereby increasing delivery of riverine 44 nutrients to the oceans and potentially also to large inland lakes 17 . In the marine 45 realm, the consequential increase in primary productivity and carbon flux to the sea 46 floor is credited with enhancing the burial of planktonic material in relatively deep 47 continental-margin sites, whereas in shallower water semi-restricted marine basins, 48 chemical and physical water-column stratification likely aided the burial of organic 49 matter 17 . Particularly in northern Europe, the evidence points to regional to global 50 development of anoxic/euxinic (sulphide-rich) bottom waters that strongly affected 51 palaeoceanographic conditions and marine ecosystems 15,17,18 . Globally significant 52 burial of 13 C-depleted photosynthetically derived organic matter commonly produced 53 an overarching positive carbon-isotope excursion (CIE) interrupted by the 54 3 characteristic abrupt negative shift that invariably characterizes the T-OAE (early 55Toarcian tenuicostatum−falciferum ammonite biozones) 1,2,18 . 56

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Section: [223] Palynostratigraphymentioning

confidence: 57%

Section: [223] Palynostratigraphymentioning

confidence: 97%

Section: [223] Palynostratigraphymentioning

confidence: 99%

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Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

et al. 2017

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“…[48] Many previous models for the formation of the organic-rich sediments in the Lower Toarcian of NW Europe have postulated that they accumulated as a response to restriction imposed by isolation of a subpycnoclinal water mass beneath a lower-salinity surface layer, a model often termed the Küspert model [Küspert,1982;Saelen et al, 1996Saelen et al, , 1998Saelen et al, , 2000Röhl et al, 2001;Schmid-Röhl et al, 2002;Bailey et al, 2003;Schwark and Frimmel, 2004;van de Schootbrugge et al, 2005]. This model works, for several reasons.…”

Section: Case For a Pycnoclinementioning

confidence: 99%

“…[4] Other palaeoenvironmental interpretations of European black shales hold that they formed in response to water mass restriction in, for example, silled basins, in which anoxic or euxinic bottom water was separated by a pycnocline from a surface water mass of low salinity that isolated the underlying water from atmospheric oxygen [Küspert, 1982;Saelen et al, 1996Saelen et al, , 1998Saelen et al, , 2000Röhl et al, 2001;Schmid-Röhl et al, 2002;Schmid-Röhl and Röhl, 2003;Schwark and Frimmel, 2004;van de Schootbrugge et al, 2005]. These models invoke local processes, such as basin restriction via salinity stratification, as the driving force for deposition of these shales: their formation is thus detached from global events.…”

Section: Introductionmentioning

confidence: 99%

Basinal restriction, black shales, Re‐Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event

et al. 2008

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[1] Profiles of Mo/total organic carbon (TOC) through the Lower Toarcian black shales of the Cleveland Basin, Yorkshire, United Kingdom, and the Posidonia shale of Germany and Switzerland reveal water mass restriction during the interval from late tenuicostatum Zone times to early bifrons Zone times, times which include that of the putative Early Toarcian oceanic anoxic event. The degree of restriction is revealed by crossplots of Mo and TOC concentrations for the Cleveland Basin, which define two linear arrays with regression slopes (ppm/%) of 0.5 and 17. The slope of 0.5 applies to sediment from the upper semicelatum and exaratum Subzones. This value, which is one tenth of that for modern sediments from the Black Sea (Mo/TOC regression slope 4.5), reveals that water mass restriction during this interval was around 10 times more severe than in the modern Black Sea; the renewal frequency of the water mass was between 4 and 40 ka. The Mo/TOC regression slope of 17 applies to the overlying falciferum and commune subzones: the value shows that restriction in this interval was less severe and that the renewal frequency of the water mass was between 10 and 130 years. The more restricted of the two intervals has been termed the Early Toarcian oceanic anoxic event but is shown to be an event caused by basin restriction local to NW Europe. Crossplots of Re, Os, and Mo against TOC show similar trends of increasing element concentration with increase in TOC but with differing slopes. Together with modeling of 187 Os/ 188 Os and d 98 Mo, the element/TOC trends show that drawdown of Re, Os, and Mo was essentially complete during upper semicelatum and exaratum Subzone times (Mo/TOC regression slope of 0.5). Drawdown sensitized the restricted water mass to isotopic change forced by freshwater mixing so that continental inputs of Re, Os, and Mo, via a low-salinity surface layer, created isotopic excursions of up to 1.3% in d 98 Mo and up to 0.6% for 187 Os/ 188 Os. Restriction thereby compromises attempts to date Toarcian black shales, and possibly all black shales, using Re-Os chronology and introduces a confounding influence in the attempts to use d 98 Mo and initial 187 Os/ 188 Os for palaeo-oceanographic interpretation.

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Why are the δ¹³C_org values in Phanerozoic black shales more negative than in modern marine organic matter?

Meyers

2014

Geochem Geophys Geosyst

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The d13 C org values of Phanerozoic black shales average 227&, whereas those of modern marine organic matter average 220&. The black shale isotopic values mimic those of continental organic matter, yet their organic geochemical properties mandate that they contain predominantly marine organic matter. Hypotheses that proposed to explain the low d13 C values of black shales include diagenetic losses of isotopically heavier organic matter components, releases of isotopically light carbon from methane clathrates or extensive magmatic events, greater photosynthetic discrimination against 13 C during times of higher atmospheric pCO 2 , and greenhouse climate stratification of the surface ocean that magnified photic zone recycling of isotopically light organic matter. Although the last possibility seems contrary to the vertical mixing that leads to the high productivity of modern oceanic upwelling systems, it is consistent with the strongly stratified conditions that accompanied deposition of the organic carbon-rich Pliocene-Pleistocene sapropels of the Mediterranean Sea. Because most Phanerozoic black shales contain evidence of photic zone anoxia similar to the sapropels, well-developed surface stratification of the oceans was likely involved in their formation. Existence of isotopically light land plant organic matter during several episodes of extensive magmatism that accompanied black shale deposition implies massive release of mantle CO 2 that added to the greenhouse conditions that favored oceanic stratification. The 13 C depletion common to most Phanerozoic black shales apparently resulted from a greenhouse climate associated with elevated atmospheric pCO 2 that led to a strongly stratified ocean and photic zone recycling of organic matter in, augmented by magmatic CO 2 releases.

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Contrasting watermass conditions during deposition of the Whitby Mudstone (Lower Jurassic) and Kimmeridge Clay (Upper Jurassic) formations, UK

Cited by 93 publications

References 79 publications

Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

Basinal restriction, black shales, Re‐Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event

Why are the δ¹³C_org values in Phanerozoic black shales more negative than in modern marine organic matter?

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Contrasting watermass conditions during deposition of the Whitby Mudstone (Lower Jurassic) and Kimmeridge Clay (Upper Jurassic) formations, UK

Cited by 93 publications

References 79 publications

Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

Carbon sequestration in an expanded lake system during the Toarcian oceanic anoxic event

Basinal restriction, black shales, Re‐Os dating, and the Early Toarcian (Jurassic) oceanic anoxic event

Why are the δ13Corg values in Phanerozoic black shales more negative than in modern marine organic matter?

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Why are the δ¹³C_org values in Phanerozoic black shales more negative than in modern marine organic matter?