1st datings of ammonite-bearing Bajocian suites from Caucasus (Georgia) - K-Ar ages of volcanic hornblendes
Détails
ID Serval
serval:BIB_832FE98C9FB2
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
1st datings of ammonite-bearing Bajocian suites from Caucasus (Georgia) - K-Ar ages of volcanic hornblendes
Périodique
Comptes Rendus de l'Académie des Sciences - Série II
ISSN-L
1251-8069
Statut éditorial
Publié
Date de publication
1993
Peer-reviewed
Oui
Volume
317
Pages
629-638
Langue
anglais
Notes
ISI:A1993LY80700011
Résumé
Volcanic flows and tuffs interbedded with ammonite-bearing sediments
directly correlatable with the stratotype section of the Bajocian stage
have been dated for the first time within the Caucasus area. Three
samples, each from a different section, allowed separation of
well-preserved brown hornblende; these are considered reliable
geochronometers in a region where subsequent volcanic activity occurred.
The dated separates are V139: a volcanic layer probably near the base,
V142 another layer near the top of the Lower Bajocian substage; V141 a
boulder from a latest Bajocian volcanic conglomerate. From bottom to
top, apparent ages at 173.5 +/- 2.6, 164.8 +/- 2.5 and 167.1 +/- 1.9 Ma
(analytical uncertainty, 95% confidence level) respectively, can be
calculated. The consistency of the results is obtained if the dated
boulder is interpreted as derived from an underlying layer, The
Bajocian-Bathonian boundary is much younger than commonly accepted and
younger than 164 Ma.
directly correlatable with the stratotype section of the Bajocian stage
have been dated for the first time within the Caucasus area. Three
samples, each from a different section, allowed separation of
well-preserved brown hornblende; these are considered reliable
geochronometers in a region where subsequent volcanic activity occurred.
The dated separates are V139: a volcanic layer probably near the base,
V142 another layer near the top of the Lower Bajocian substage; V141 a
boulder from a latest Bajocian volcanic conglomerate. From bottom to
top, apparent ages at 173.5 +/- 2.6, 164.8 +/- 2.5 and 167.1 +/- 1.9 Ma
(analytical uncertainty, 95% confidence level) respectively, can be
calculated. The consistency of the results is obtained if the dated
boulder is interpreted as derived from an underlying layer, The
Bajocian-Bathonian boundary is much younger than commonly accepted and
younger than 164 Ma.
Création de la notice
11/12/2012 16:25
Dernière modification de la notice
20/08/2019 15:43