Data/hora: 06/06/2024 03:30:38

Provedor de dados: | 5
País: | France
Título: | The crustal structure of the north-eastern Gulf of Aden continental margin: insights from wide-angle seismic data
Autores: | Watremez, Louise; Leroy, Sylvie; Rouzo, Stephane; D'Acremont, E.; Unternehr, P.; Ebinger, C.; Lucazeau, F.; Al-lazki, A.
Data: | 2011-02
Ano: | 2011
Palavras-chave: | Controlled source seismology; Continental margins: divergent; Crustal structure; Indian Ocean.
Resumo: | P&gt;The wide-angle seismic (WAS) and gravity data of the Encens survey allow us to determine the deep crustal structure of the north-eastern Gulf of Aden non-volcanic passive margin. The Gulf of Aden is a young oceanic basin that began to open at least 17.6 Ma ago. Its current geometry shows first- and second-order segmentation: our study focusses on the Ashawq-Salalah second-order segment, between Alula-Fartak and Socotra-Hadbeen fracture zones. Modelling of the WAS and gravity data (three profiles across and three along the margin) gives insights into the first- and second-order structures. (1) Continental thinning is abrupt (15-20 km thinning across 50-100 km distance). It is accommodated by several tilted blocks. (2) The ocean-continent transition (OCT) is narrow (15 km wide). The velocity modelling provides indications on its geometry: oceanic-type upper-crust (4.5 km s-1) and continental-type lower crust (&gt; 6.5 km s-1). (3) The thickness of the oceanic crust decreases from West (10 km) to the East (5.5 km). This pattern is probably linked to a variation of magma supply along the nascent slow-spreading ridge axis. (4) A 5 km thick intermediate velocity body (7.6 to 7.8 km s-1) exists at the crust-mantle interface below the thinned margin, the OCT and the oceanic crust. We interpret it as an underplated mafic body, or partly intruded mafic material emplaced during a 'post-rift' event, according to the presence of a young volcano evidenced by heat-flow measurement (Encens-Flux survey) and multichannel seismic reflection (Encens survey). We propose that the non-volcanic passive margin is affected by post-rift volcanism suggesting that post-rift melting anomalies may influence the late evolution of non-volcanic passive margins.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00200/31102/29507.pdf

DOI:10.1111/j.1365-246X.2010.04881.x

Editor: | Wiley-blackwell
Relação: | http://archimer.ifremer.fr/doc/00200/31102/
Formato: | application/pdf
Fonte: | Geophysical Journal International (0956-540X) (Wiley-blackwell), 2011-02 , Vol. 184 , N. 2 , P. 575-594
Fonte: | 2010 The Authors Geophysical Journal International, 2010 RAS