The Toarcian Oceanic Anoxic Event (Early Jurassic) in the Neuquén Basin, Argentina: A Reassessment of Age and Carbon Isotope Stratigraphy

Suwaidi, Aisha Al; Hesselbo, Stephen P.; Damborenea, Susana E.; Manceñido, Miguel O.; Jenkyns, Hugh C.; Riccardi, Alberto; Angelozzi, Gladys N.; Baudin, François

doi:10.1086/684831

Cited by 57 publications

(24 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, other coastal basins with high organic carbon burial may have existed elsewhere on Earth, as published sections are currently geographically limited. However, several sites with high organic carbon during the T‐OAE have been found in, for example, the Neuquén Basin and Yakon River (Argentina; Al‐Suwaidi et al, , ), Haida Gwaii (British Columbia, Canada; Caruthers et al, ), and Toyora (Japan; Kemp & Izumi, ). In addition, other anoxic basins in which sediments are no longer preserved may have developed during the T‐OAE.…”

Section: Discussionmentioning

confidence: 99%

Ocean Circulation in the Toarcian (Early Jurassic): A Key Control on Deoxygenation and Carbon Burial on the European Shelf

Baroni

Pohl

Helmond

et al. 2018

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

The Toarcian Oceanic Anoxic Event (T‐OAE, ∼183 Myr) was a long‐lasting episode of ocean deoxygenation during the Early Jurassic. The event is related to a period of global warming and characterized by major perturbations to the hydrological and carbon cycles with high rates of organic matter burial in shelf seas. Ocean circulation during the Toarcian and its influence on marine biogeochemical cycles are still not fully understood. Here we assess the spatial extent of anoxia in the NW Tethys Ocean during the T‐OAE, the relationship with ocean circulation and the impact on organic carbon burial, using new and existing sedimentary records from the European Epicontinental Shelf in combination with general circulation model results. We demonstrate that bottom waters on the southwestern part of the shelf were mainly oxic during the T‐OAE, while those in the northeastern basins were mostly anoxic or even sulfidic. Results for two ocean‐atmosphere models (Fast Ocean‐Atmosphere Model and Massachusetts Institute of Technology general circulation model) suggest the presence of a strong clockwise gyre over the European Epicontinental Shelf, which brought oxygenated equatorial waters from the Tethys Ocean to the southern shelf. The northward limb of the gyre was significantly weakened due to the rough bathymetry of the northern shelf, making this relative small region highly sensitive to local ocean stratification. These sluggish ocean dynamics promoted bottom water anoxia and enhanced burial of organic carbon in the northeastern basins, which accounted for 3–5% of the total carbon extracted from the ocean‐atmosphere system as recorded by the positive carbon isotope shift.

show abstract

Section: Discussionmentioning

confidence: 99%

Ocean Circulation in the Toarcian (Early Jurassic): A Key Control on Deoxygenation and Carbon Burial on the European Shelf

Baroni

Pohl

Helmond

et al. 2018

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

show abstract

“…Nonetheless, even if local processes can modulate the shape and magnitude of the carbon‐isotope profiles (e.g. Trabucho‐Alexandre, ; Them et al ., ), the global occurrence of the carbon cycle perturbation is now well‐recognized by the presence of the negative CIE in widely distributed palaeogeographic sites, in marine carbonate carbon, marine and terrestrial organic carbon and specific organic compounds (Hesselbo et al ., ; Kemp et al ., ; Van Breugel et al ., ; Hermoso et al ., , ; Caruthers et al ., ; Gröcke et al ., ; Hesselbo & Pienkowski, ; Suan et al ., , ; French et al ., ; Kemp & Izumi, ; Al‐Suwaidi et al ., ; Bodin et al ., ; Them et al ., ; Xu et al ., ). The negative CIE is commonly attributed to the massive release of isotopically light carbon to the exogenic reservoirs, related to any one or a combination of the following processes: (i) CO 2 degassing during the formation of the Karoo–Ferrar large igneous province (LIP) (Duncan et al ., ; Pálfy & Smith, ); (ii) thermogenic methane (CH 4 ) release related to sill emplacement in the Karoo–Ferrar province (McElwain et al ., ; Svensen et al ., ); (iii) destabilization of CH 4 hydrates from marine sediments (Hesselbo et al ., ), modulated by orbital forcing (Kemp et al ., , ); and (iv) release of CH 4 from terrestrial environments (Pienkowski et al ., ; Them et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Expression of the Toarcian Oceanic Anoxic Event: New insights from a Swiss transect

et al. 2018

View full text Add to dashboard Cite

A sedimentological, biostratigraphical and geochemical (stable isotopes and Rock‐Eval parameters) analysis was performed on four Swiss successions, in order to examine the expression of the Toarcian Oceanic Anoxic Event along a north–south transect, from the Jura through the Alpine Tethys (Sub‐Briançonnais and Lombardian basins). The locations were selected to represent a range of palaeoceanographic positions from an epicontinental sea to a more open marine setting. The Toarcian Oceanic Anoxic Event was recognized by the presence of the characteristic negative carbon‐isotope excursion in carbonate (ca 2 to 4‰) and organic matter (ca 4 to 5‰) at the base of the falciferum ammonite Zone (NJT6 nannofossil Zone). The sedimentary expression of the Toarcian Oceanic Anoxic Event varies along the transect from laminated mudstone rich in total organic carbon (≤11 wt.%) in the Jura, to thin‐bedded marl (≤5 wt.% total organic carbon) in the Sub‐Briançonnais Basin and to hemipelagic reddish marly limestone (total organic carbon <0·05 wt.%) in equivalent levels from the Lombardian Basin. The carbon‐isotope excursion is thus independent of facies and palaeoceanographic position. The low nannofossil abundance and the peak in Calyculaceae in the Jura and the Sub‐Briançonnais Basin indicate low salinity surface waters and stratified water masses in general. Sedimentological observations (for example, obliquely‐bedded laminae and homogeneous mud layers containing rip‐up clasts) indicate the presence of dynamic conditions, suggesting that water mass stratification was episodically disrupted during the Toarcian Oceanic Anoxic Event. The proposed correlation highlights a stratigraphic gap and/or condensed interval between the Pliensbachian–Toarcian boundary and the Toarcian Oceanic Anoxic Event interval (most of the tenuicostatum ammonite Zone is missing), which is also observed in coeval European sections and points to the influence of sea‐level change and current dynamics. This transect shows that the sedimentary expression of the Toarcian Oceanic Anoxic Event is not uniform across the Alpine Tethys, supporting the importance of local conditions in determining how this event is recorded across different palaeoceanographic settings.

show abstract

“…; Al‐Suwaidi et al . ; and reference therein). Globally, this T‐OAE is characterized by laminated, organic‐rich black shales, which are generally interpreted as a consequence of global anoxia (e.g.…”

mentioning

confidence: 98%

Selective incidence of the toarcian oceanic anoxic event on macroinvertebrate marine communities: a case from the Lusitanian basin, Portugal

Miguez‐Salas

Rodrı́guez-Tovar

Duarte

2017

LET

View full text Add to dashboard Cite

A macroinvertebrate assemblage has been studied from the Thin Nodular Limestones Member (TNL) of the Fonte Coberta section (Lusitanian Basin, Portugal), giving special attention to its trace fossils. The assemblage was studied to analyse the influence of the Toarcian Oceanic Anoxic Event (T‐OAE) on the macroinvertebrate community. The TNL consists of thin alternations of marl/limestone and nodular limestone beds, showing clear differentiations from bottom to top. Integrative analysis of the macrofossil assemblage for the studied interval, conducted for the first time in the Lusitanian Basin, reveals three major features: (1) abundant trace fossils with dominance or near exclusiveness of Thalassinoides, and a local record of Spongeliomorpha; (2) scarcity, but not extinction, of ammonoids; and (3) the absence of previously abundant brachiopods. The findings reveal a selective incidence of the T‐OAE on the macrobenthic community, with a major influence (extinction) of brachiopods, severe changes (diminution in abundance and diversity) on ammonoids and a minor effect on macrobenthic tracemakers. A complex relationship between different palaeoenvironmental conditions during the T‐OAE can be interpreted, discarding anoxic conditions in the seafloor, although low oxygen conditions in the water column are a possibility. The increase in seawater temperature and availability of nutrients on the seafloor would have played an influential role.

show abstract

The Toarcian Oceanic Anoxic Event (Early Jurassic) in the Neuquén Basin, Argentina: A Reassessment of Age and Carbon Isotope Stratigraphy

Cited by 57 publications

References 64 publications

Ocean Circulation in the Toarcian (Early Jurassic): A Key Control on Deoxygenation and Carbon Burial on the European Shelf

Ocean Circulation in the Toarcian (Early Jurassic): A Key Control on Deoxygenation and Carbon Burial on the European Shelf

Expression of the Toarcian Oceanic Anoxic Event: New insights from a Swiss transect

Selective incidence of the toarcian oceanic anoxic event on macroinvertebrate marine communities: a case from the Lusitanian basin, Portugal

Contact Info

Product

Resources

About