Data/hora: 02/06/2024 08:21:24

Provedor de dados: | Institutional Archive of Ifreme (ArchiMer)
País: | France
Título: | 40 AR/39 AR ages for the alkaline volcanism and the basement of Gorringe Bank, North atlantic Ocean
Autores: | Feraud, Gilbert; Gastaud, Janine; Auzende, Jean-marie; Olivet, Jean-louis; Cornen, Guy.
Data: | 1981-08
Ano: | 1981
Palavras-chave: | Histoire Ifremer.
Resumo: | Gorringe Bank is situated on the Europe-Africa plate boundary at the eastern end of the Azores-Gibraltar fracture zone. It has two summits. Gettysburg Bank to the southwest and Ormonde Bank to the northeast. We applied the 40Ar/39AR stepwise heating method to date six samples of the alkaline volcanic rocks. Two gabbros from the Ormonde Bank and a dolerite from the Gettysburg Bank. The results suggest that the alkaline volcanism lasted probably for less than 6 Ma(66-60 Ma). Although the nature of this volcanism precludes any subduction feature during its setting. the alkaline volcanism of Ormonde is probably linked to Upper Cretaceous/Eocene compressive tectonic events.  The basement rocks of Gorringe Bank reveal disturbed 40Ar/39Ar age spectra.  One plagioclase and one biotite from a gabbrogive evidence for a thermic event whose age is tentatively estimated al about 75 Ma, and relared to a variation in the direction of the relative movement between Europe and Africa. The more probable age given by a plagioclase of another gabbro and by a dolerite (110 Ma) corresponds to tilting northeastward of the Gorringe massif. [NOT CONTROLLED OCR]
Tipo: | Text
Idioma: | Inglês
Identificador: | http://archimer.ifremer.fr/doc/1981/publication-5365.pdf
Relação: | http://archimer.ifremer.fr/doc/00000/5365/
Formato: | application/pdf
Fonte: | Earth and Planetary Science Letters, 1981-08 , Vol. 57 , N. 1 , P. 459-474
Fonte: | Centre Océanologique de Bretagne