A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina

A U–Pb zircon age of 164.64^0.2 Ma (95% confidence level) is reported for an ash bed, at the Bathonian–Callovian (late Middle Jurassic) boundary, determined by isotope dilution thermal ionisation mass spectrometry from individual, chemically abraded grains. The volcanic ash layer occurs within the C...

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Detalles Bibliográficos
Autores principales: Kamo, Sandra L., Riccardi, Alberto Carlos
Formato: Articulo
Lenguaje:Inglés
Publicado: 2009
Materias:
Geología
U-Pb geochronology
ammonites
biostratigraphy
Bathonian
Callovian
zircon
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/142357
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-142357
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Geología
U-Pb geochronology
ammonites
biostratigraphy
Bathonian
Callovian
zircon
spellingShingle Geología
U-Pb geochronology
ammonites
biostratigraphy
Bathonian
Callovian
zircon
Kamo, Sandra L.
Riccardi, Alberto Carlos
A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
topic_facet Geología
U-Pb geochronology
ammonites
biostratigraphy
Bathonian
Callovian
zircon
description A U–Pb zircon age of 164.64^0.2 Ma (95% confidence level) is reported for an ash bed, at the Bathonian–Callovian (late Middle Jurassic) boundary, determined by isotope dilution thermal ionisation mass spectrometry from individual, chemically abraded grains. The volcanic ash layer occurs within the Chacay Melehue Formation, Chacay Melehue section, Neuque´n Province, central west Argentina, above the last record of ammonites of the regional Lilloettia steinmanni Standard Zone, and, stratigraphically, where the first of those of the regional Eurycephalites vergarensis Standard Zone appears, generally referred to as the uppermost Bathonian and the lowermost Callovian, respectively. This ash layer represents the only known datable horizon worldwide that is directly related to a well-documented ammonite faunal succession at this boundary. The U–Pb zircon age is older than one previously reported for the same bed and closer to an estimation of 164.7^4Ma for the boundary based on the scaling durations of ammonite zones to their subzones in the sub-boreal standard zonation. The new age agrees better with the age model for the Oxfordian through Bathonian M-sequence magnetic anomalies in the Pacific and contributes to the radioisotopic age calibration of the Jurassic time scale.
format Articulo
Articulo
author Kamo, Sandra L.
Riccardi, Alberto Carlos
author_facet Kamo, Sandra L.
Riccardi, Alberto Carlos
author_sort Kamo, Sandra L.
title A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
title_short A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
title_full A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
title_fullStr A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
title_full_unstemmed A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina
title_sort new u–pb zircon age for an ash layer at the bathonian–callovian boundary, argentina
publishDate 2009
url http://sedici.unlp.edu.ar/handle/10915/142357
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