Data/hora: 01/06/2024 14:47:46

Provedor de dados: 	5	
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