SPIRAL
Type | Oceanographic cruise |
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Ship | L'Atalante |
Ship owner | Ifremer |
Dates | 26/09/2009 - 10/11/2009 |
Chief scientist(s) | GRAINDORGE David , SAGE Françoise , KLINGELHOEFER Frauke |
GEO-OCEAN - UMR 6538 Univ. Brest, CNRS, Ifremer, Univ. Bretagne Sud Place Nicolas Copernic 29280 Plouzané |
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DOI | 10.17600/9010050 |
Objective | The multi-annual partnership-based research programme SPIRAL (deep seismic and regional investigation in northern Algeria) aims to study the deep structure of the North Algerian margin using "high penetration" seismic methods: low frequency vertical reflection shooting, as well as wide angle reflection and refraction with deployment of listening stations on the seabed and onshore. The first strand of the SPIRAL programme SPIRAL involves the sea cruise to acquire geophysical data. This cruise took place aboard RV L'Atalante in two legs, respectively from 26/09 (Oran) to 10/10 2009 (Annaba) and from 13/10 (Annaba) to 10/11 2009 (Oran). These two legs provided acquisition of wide-angle seismic and penetrating multichannel seismic reflection data, which was the main objective of the project, as well as additional data like very high resolution (Chirp or sediment sounder type), magnetic and gravimetric, and multibeam bathymetric echosounder data. The profiles acquired during SPIRAL should supply elements to characterize the structural levels in and under the sediment cover (crust) down to the mantle in the targeted zones given in the cruise report; obtain accurate images of faulted and folded area and the major boundaries like the Moho; constrain the physical and rheological properties (particularly velocity models) which should help determine things like the nature of the crust at the continent-ocean transition. These constraints will make it possible to perform thermo-mechanical modelling on the scale of the Maghrebide belts to the base of the crust (temperature, density) and thus specify the main boundaries of the large crustal domains. |