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dc.contributor.author
Mazzini, Adriano
dc.contributor.author
Svensen, Henrik
dc.contributor.author
Leanza, Hector Armando
dc.contributor.author
Corfu, Fernando
dc.contributor.author
Planke, Sverre
dc.date.available
2019-01-30T18:25:47Z
dc.date.issued
2010-09
dc.identifier.citation
Mazzini, Adriano; Svensen, Henrik; Leanza, Hector Armando; Corfu, Fernando; Planke, Sverre; Early Jurassic shale chemostratigraphy and U-Pb ages from the Neuquén Basin (Argentina): Implications for the Toarcian Oceanic Anoxic Event; Elsevier Science; Earth and Planetary Science Letters; 297; 3-4; 9-2010; 633-645
dc.identifier.issn
0012-821X
dc.identifier.uri
http://hdl.handle.net/11336/69031
dc.description.abstract
New data from a Lower Jurassic shale section in the Neuquén Basin, Argentina, are presented in order to better constrain the triggering mechanism for the Toarcian Oceanic Anoxic Event (TOAE) and the associated negative carbon isotope excursion. Chemostratigraphy from a 65m thick shale-dominated marine section of Late Pliensbachian to Early Toarcian age shows the presence of a 19.5m thick interval of organic-rich black shale where the bulk rock organic carbon content reaches almost 4wt.%. The δ13C of the bulk organic matter changes from -22.3‰ in the lower parts of the profile to -29.8‰ VPDB in the black shale interval, documenting a -8‰ excursion over five stratigraphic meters. Twelve interbedded tuff layers, representing fallouts from paleo-Andean arc magmatism, were discovered in the section. Dating by ID-TIMS of zircons from two tuff beds located within the carbon isotope excursion interval gave ages of 181.42±0.24Ma and 180.59±0.43Ma. Assuming linear sedimentation rates within the black shale interval, the initiation of the anoxic event occurred at 182.16±0.6Ma, lasting until 180.16±0.66Ma. Thus the total duration is between 0.74 and 3.26Ma, taking into account the propagation of dating uncertainties. This also allowed to obtain a new and improved estimate of the Pliensbachian-Toarcian boundary. The U/Pb age of the initiation of the observed carbon isotope excursion overlaps the U/Pb emplacement ages of mafic sill intrusions in the Karoo Basin in South Africa, and supports the hypothesis that thermogenic methane released during contact metamorphism within the Karoo Basin was the main trigger of the anoxic event. Our findings show that the Toarcian carbon isotope excursion is present also in the southern hemisphere and that the TOAE was a global phenomenon likely triggered by a massive greenhouse gas release.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier Science
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Carbon Isotopes
dc.subject
Karoo Basin
dc.subject
NeuquÉN Basin
dc.subject
Toarcian Oceanic Anoxic Event
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Tuff Layers
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Zircon U-Pb Dating
dc.subject.classification
Meteorología y Ciencias Atmosféricas
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Ciencias de la Tierra y relacionadas con el Medio Ambiente
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
dc.title
Early Jurassic shale chemostratigraphy and U-Pb ages from the Neuquén Basin (Argentina): Implications for the Toarcian Oceanic Anoxic Event
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2019-01-30T13:56:23Z
dc.journal.volume
297
dc.journal.number
3-4
dc.journal.pagination
633-645
dc.journal.pais
Países Bajos
dc.journal.ciudad
Amsterdam
dc.description.fil
Fil: Mazzini, Adriano. University of Oslo; Noruega
dc.description.fil
Fil: Svensen, Henrik. University of Oslo; Noruega
dc.description.fil
Fil: Leanza, Hector Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina
dc.description.fil
Fil: Corfu, Fernando. University of Oslo; Noruega
dc.description.fil
Fil: Planke, Sverre. University of Oslo; Noruega. Oslo Research Park. Volcanic Basin Petroleum Research; Noruega
dc.journal.title
Earth and Planetary Science Letters
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.epsl.2010.07.017
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0012821X10004553
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