HR: 1330h
AN: T53A-09    [Abstracts]
TI: Geological Constraints on the Evolution of the Angolan Margin Based on Reflection and Refraction Seismic Data (Za‹Ango project)
AU: * Moulin, M
EM: maryline.moulin@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Aslanian, D
EM: daniel.aslanian@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Olivet, J
EM: jean.louis.olivet@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Contrucci, I
EM: ico@soc.soton.ac.uk
AF: Southampton Oceanography Centre, Challenger Division Empress Dock, Southampton, SO14 3ZH United Kingdom
AU: Matias, L
EM: lmatias@fc.ul.pt
AF: Centro de Geofisica da Universidade de Lisboa, Rua escola Politecnica 58, LISBOA, 1269-102 Portugal
AU: Geli, L
EM: louis.geli@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Klingelhoefer, F
EM: Frauke.Klingelhoefer@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Nouze, H
EM: herve.nouze@ifremer.fr
AF: Ifremer, Centre de Brest DRO/Geosciences Marines BP 70, PLOUZANE, 29280 France
AU: Rabineau, M
EM: marina.rabineau@univ-brest.fr
AF: Universite de Bretagne Occidentale IUEM-UMR6538, Laboratoire Domaines Oceaniques Place Nicolas Copernic, PLOUZANE, 29280 France
AU: Labails, C
EM: cinthia.labails@ifremer.fr
AF: Universite de Bretagne Occidentale IUEM-UMR6538, Laboratoire Domaines Oceaniques Place Nicolas Copernic, PLOUZANE, 29280 France
AU: rehault, J
EM: rehault@univ-brest.fr
AF: Universite de Bretagne Occidentale IUEM-UMR6538, Laboratoire Domaines Oceaniques Place Nicolas Copernic, PLOUZANE, 29280 France
AU: Unternehr, P
EM: patrick.unternehr@total.com
AF: Total, Exploration-Production/Geosciences/Projets Nouveaux/Expertise Geodynamique 2, place de la Coupole La defense 6, Paris La Defense, 92078 France
AB: Deep penetration multi-channel reflection and OBS wide-angle seismic data from the Congo-Angola margin were collected in 2000 during the ZaiAngo cruise (Ifremer and Total). These data help constrain the deep structure of the non-volcanic continental margin, the geometry of the pre-salt sediment layers and the geometry of the Aptian salt layer. Dating the deposition of the salt relative to the chronology of the margin formation is an issue of fundamental importance for reconstructing the evolution of the margin and for the understanding of the crustal thinning processes. The data show that the crust thins abruptly, from a 30 - 40km thickness to less than 10km, over a lateral distance of less than 50km. The transitional domain is a 180km wide basin with a thickness lower than 7 km. The pre-salt sediment layering within this basin is parallel to the base of the salt and hardly affected by tectonic deformation. In addition, the presence of a continuous salt cover, from the continental platform down to the presumed oceanic boundary, provides indications on the conditions of salt deposition that constrain the geometry of the margin at that time. These crucial observations imply shallow deposition environments during the rifting and suggest that vertical motions prevailed - compared to horizontal motions - during the formation of the basin.
DE: 8105 Continental margins and sedimentary basins
DE: 8109 Continental tectonics--extensional (0905)
DE: 8122 Dynamics, gravity and tectonics
DE: 8130 Heat generation and transport
DE: 8159 Rheology--crust and lithosphere
SC: Tectonophysics [T]
MN: 2005 Joint Assembly