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Ocean sediment and rock collection
The oceanic collection consists of sediment cores and dragged sediments, mainly collected by crews on the French ship, the Marion Dufresne. These rocks and sediments are the result of more than 30 years of oceanographic campaigns coming mostly from the Indian Ocean but also from the Red Sea, the Mediterranean Sea, the Atlantic Ocean, the Caspian Sea and the Pacific Ocean.
Presentation
The oceanic collection consists of around 980 marine cores representing more than 8 km of rocks. Sediment cores can reach lengths of over 50 metres. Depending where cores were taken, this thickness could represent thousand up to millions of years. In order to be stored, each core is cut into sections of around 1.50 metres and preserved in cold rooms at 7°C and a hygrometry of 70-80%.
Besides cores, several thousands polymetallic nodules and various rocks from dredgings carried out during the 1970s and 1980s, mainly from the Indian Ocean, are stored in our collection. Each dredging, stored at room temperature, may represent several tones of oceanic rocks.
Hundreds of films, photographs of the seabed, rocks and sediments complete the collection.
Section d’une carotte avec alternances des sédiments riches en goethite et sidérite et des boues carbonatées
© J.-P. Giannesini
Sédiment marin prélevé au nord de l’océan Indien, dans le passage des Amirantes de 55 Ma d'âge
© E. Moreno
Échantillonnage du carottier CASQ en sections de 1, 50 mètres
© E. Moreno
Carottier géant Calypso au bord du Marion Dufresne
© E. Moreno
Carottier à grand section CASQ au bord du Marion Dufresne
© E. Moreno
Carottier géant Calypso au bord du Marion Dufresne
© E. MorenoHistory
The oceanic collection is very recent compared to the other Muséum’s collections. It was initiated in 1973 with the development of new tools that enabled deep sea coring. The boat Marion Dufresne 1, chartered by the TAAF (French Southern and Antarctic Lands) and built in 1972, developed a coring system in the 80s that could reach lengths of up to 30 metres.
Currently the Marion Dufresne 2 Calypso corer (commissioned in 1995) enables coring of up to 60 metres of sediment at depths of up to 5,000 metres of water depth. Since then other tools have been developed, like the CASQ corer, which is still on board the Marion Dufresne 2 and is used to sample very large square cores.
Research
The purpose of this collection is mainly for scientific research. However, few samples are used to testify the complexity of ocean floors and find places in several exhibitions inside and outside the Muséum.
Ocean cores form the basis for palaeoclimatic studies (study of ancient climates). The sediment’s mineralogical composition and the many microfossils it contains, enable us to learn about and reconstruct the climate and oceanic conditions of the past. Only half of the core (the work sections) is used for sampling, while the other half is stored (archive sections). The samples resulting from dragging are made up of rocks (basalts, peridotites, gabbros, etc.) from mid-ocean ridges, cobalt crusts and polymetallic nodules. These millimetric up to centimetric nodules are spherules built up by concentric circles of iron and manganese hydroxides encrusted around a core generally a small grain of sediment. They are rich in copper, nickel and cobalt.
Contact
Eva Moreno, Senior Lecturer, Collection Manager
eva.moreno [@] mnhn.fr