The collection includes 980 marine sediment cores, representing a cumulative length of about 8 km. Each core, which can measure over 50 meters, provides a true natural archive of Earth's history. Depending on the sampling sites, they cover periods ranging from several thousand to several million years. These samples are crucial for the study of paleoclimate, paleoseismicity (traces of past earthquakes), and volcanology.

The cores are preserved in 1.5-meter sections: a working section, used for analysis, and an archive section, reserved for nondestructive studies. These sections are stored in cold chambers at low temperatures and high humidity to prevent drying. Additionally, surface sediment samples are kept in specialized boxes.
The collection also includes over 20 tons of polymetallic nodules and encrustations, as well as volcanic rocks, and more rarely, carbonate rocks. These samples were collected during dredging campaigns in the 1970s and 1980s, with each dredging potentially representing up to one ton of material. These samples are stored at room temperature in suitable containers.

In addition to the samples, thousands of films and photographs of the seafloor, taken with underwater cameras, enrich our understanding of marine ecosystems and oceanic geology.

The Oceanic Collection was founded in 1973 by Lucien Leclaire, professor at the National Museum of Natural History, holder of the geology chair. Despite its relative youth compared to other collections at the Museum, it stands out for its richness and scientific value. Some samples come from regions that are now inaccessible for geopolitical reasons, such as the Red Sea and the coasts of Somalia and Socotra.
Lucien Leclaire defended his thesis on the sedimentology of the Mediterranean continental shelf before focusing on the exploration of the Indian Ocean, particularly polymetallic nodule fields. He later became interested in studying the seafloor of the tropical zone of the Indian Ocean, a region whose oceanic compositions were still poorly understood in the 1970s.

The collection is closely linked to the Marion Dufresne I and II oceanographic vessels. Inaugurated in 1973, the Marion Dufresne I allowed the Museum team to participate in its first campaign. Replaced in 1995 by the longer and more technologically advanced Marion Dufresne II, this vessel remains a crucial research tool, capable of retrieving cores up to 70 meters long and from depths greater than 5,000 meters.

The Oceanic Collection is an essential tool for science and owes its existence to technological advancements in deep-sea coring and dredging, as well as the development of laboratory analysis techniques. These innovations allow for unprecedented precision in reconstructing past climatic and environmental variations, making this collection central to research on the history of our planet..

This collection primarily serves scientific purposes and is frequently requested for loans.
The sediment cores are used for various research projects, particularly in paleoclimatic studies, the analysis of ancient climate, as well as the study of earthquakes and volcanic eruptions. Some samples are also requested for exhibitions, both at the Museum and at external locations.

We also have polymetallic nodule samples, basalt, peridotite, and gabbro collected through deep-sea dredging. Polymetallic nodules, rich in strategic metals such as iron, manganese, cobalt, and nickel, were collected to study their formation, mining potential, and environmental impact. Finally, the study of basalts, peridotites, and gabbros is crucial to understanding the dynamics of the Earth's crust, particularly the geological processes occurring at the oceanic ridges and within the Earth's mantle.

Eva Moreno, senior lecturer at the Muséum national d'Histoire naturelle, scientific manager of the collection
eva.moreno [@] mnhn.fr