MOHNS RIDGE 2

Name: MOHNS RIDGE 2
Start: 1988-07-27
End: 1988-08-31
Location: Norwegian Sea

Type	Oceanographic cruise
Ship	Le Suroît
Ship owner	Ifremer
Dates	27/07/1988 - 31/08/1988
Chief scientist(s)	AVEDIK Felix
	GEO-OCEAN - UMR 6538 Univ. Brest, CNRS, Ifremer, Univ. Bretagne Sud Place Nicolas Copernic 29280 Plouzané https://www.geo-ocean.fr/
DOI	10.17600/88002411
Objective	Structure and dynamics of oceanic ridges. Hydrothermal circulation. Determining the mean seismic structure at the axis of the Mohns Ridge. Tomographic study of an "active" accretion zone. Study on the evolution of the crustal structure and its physical properties depending on the Age. Special attention is given to studying the rate at which fissures form there, once of the key parameters in hydrothermal circulation. Cruise's international framework: Franco-Norwegian cooperation; the Mobil Search vessel performed a 60 km multichannel seismic survey across the ridge in 1987; in August 1988, RV Hakon Moby (University of Bergen) performed a 100 km multichannel seismic survey using the mapping results for Mohns Ridge.

Sea/Ocean

Norwegian Sea

Ports

Port of departure : Brest (France)

Port of return : Brest (France)

Project

EUROSEISMIC EUROPEAN SEISMIC METADATA AND INFORMATION CENTRE

Scientific Authority

GÉOSCIENCES MARINES

Centre Ifremer Bretagne

ZI Pointe du Diable

29280 Plouzané

+33(0)2 98.22.42.24

Participating bodie(s)

IFREMER,IPG (Paris), Université de Bergen (Norvege)

Discipline(s)

MARINE GEOSCIENCES

Code	Label	Quantity	PI
G26	Seismic refraction 1000 shots at 4 knots	-	AVEDIK Felix
G75	Single channel seismic reflection	-	AVEDIK Felix

Summary of measurements

-36 moorings of ocean bottom seismic instruments (OBH and OBVSA) were deployed, providing 34 good-quality recordings.
-1,700 km of single-channel seismic survey (at 10 knots) with 2 canons TWG S-80 guns.
-500 km of combined refraction/reflection profiles representing 7 profiles with a mean length of 70 km, using four 9L airguns (rate of shots 25 msec, shotpoint interval 100 m).
-60 km of seismic refraction along the axis of the ridge, recorded with 5 OBH stations, eight 16.4L airguns (shot rate 120 sec, shotpoint interval 250 m).
-2 tomography experiments were conducted, representing 1,000 shots and 260 km of additional profiles (surface area of 2 x 250 Km2), making 10 instruments on seabed (OBH) in all, including the OBVSA vertical seismic array.

Location map

Positionning system

Geodetic system : VALEUR INDEFINIE

Positioning system : Sat Fix + Loran C

Data managed by SISMER

Bibliography

References of Articles published in other Periodicals or Scientific Works acclaimed in the Field

Geli Louis (1991). Étude de la dorsale de Mohn, au voisinage de 72°N, en Mer de Norvège et du Groenland : Corrélation entre événements sédimentaires et réajustements tectono-volcaniques survenus à la fin du Miocène. Comptes Rendus de l'Academie des Sciences Serie II, 313(13), 1569-1578.

Geli Louis (1991). Étude de la dorsale de Mohn, au voisinage de 72°N, en Mer de Norvège et du Groenland :Mise en évidence de différentes phases locales d'expansion, du Miocène Supérieur à l'Actuel. Comptes Rendus de l'Academie des Sciences Serie II, 313(11), 1291-1300.

References of Technical Reports

Dyment Jérôme, Lallier François, Le Bris Nadine, Rouxel Olivier , Sarradin Pierre-Marie , Lamare Sylvain, Coumert Coralie, Morineaux Marie, Tourolle Julie (2014). Les impacts environnementaux de l’exploitation des ressources minérales marines profondes. Expertise scientifique collective. Rapport, CNRS – Ifremer, 937 p. https://archimer.ifremer.fr/doc/00872/98434/

(1988) Compte-rendu de Campagne. Mohns Ridge 2.