Marine Expedition Sheds Light on the Interior of the Earth

From Hannover to the Southwest Indian Ridge: Between 6 March and 12 April 2020, a team from the Institute of Mineralogy at Leibniz University Hannover (LUH) will travel across the Indian Ocean aboard the research vessel SONNE.

Led by Prof. Dr. Jürgen Koepke, the team from Hannover will be accompanied by colleagues from Berlin, Bremen, Erlangen and Münster, as well as researchers from the United States, China, Italy and Finland. Starting in Cape Town, the expedition is headed for the Marion Rise before reaching Durban in five weeks’ time.

The team intends to conduct research using a diving robot of the Center for Marine Environmental Science (MARUM), a research facility of Bremen University. Missions will be broadcasted via live stream. The voyage focuses on analysing rock samples retrieved from the seabed.

Understanding the mechanisms behind plate tectonics

The site of the study, the Marion Rise, is located on the Southwest Indian Ridge, which separates Africa from the Antarctic. At the ridge, two divergent tectonic plates move apart in ultra slow motion. They spread less than one centimetre a year – other tectonic plate boundaries move more than ten centimetres in the same period. This extremely slow spreading rate causes a unique situation.

“Other ridge boundaries are covered by volcanic rock from near-surface layers of the earth. At the Southwest Indian Ridge this occurs via tectonic activity, which forms geographic features such as mountain ranges”, explains Professor Koepke. During this process, material originating from the interior of the planet – the Earth’s mantle – surfaces to the seabed.

“Mantle rock on the surface of the Earth is incredibly rare. We therefore intend to collect samples and analyse them using a complex procedure”, says the mineralogist. The team aims to gain a better understanding of the mechanisms that cause tectonic plates to move apart in ultra slow motion. “The LUH researchers will bridge a gap in basic research”, summarises Koepke.

Within the scope of the expedition, the research teams intend to create a map of the area by determining the topography, as well as the gravitational field and magnetism of the seabed. Moreover, they aim to understand why this section of the Southwest Indian Ridge, the Marion Rise, moved upwards.

“Such a plateau is an anomaly, comparable to Iceland”, says Koepke adding “There is a theory that the Marion Rise – just as Iceland – originated from a hotspot, an area of long-term volcanic activity within the mantle of the Earth. However, we assume that there is another explanation, going back to the time when the Antarctic and Africa were still connected within the supercontinent of Gondwana”, says Koepke.

Live stream from the seabed

In addition to collecting rock samples and scientific data, the diving robot MARUM-QUEST will transmit live footage of the missions, which will be incorporated into suitable museum events throughout Germany. The live stream from the seabed will feature an audio commentary from crew members answering questions from the audience.

“We would like to interact with the audience – questions are actively encouraged”, emphasises Koepke. A public event will be held at Leibniz University Hannover on 18 March 2020 at 5 p.m. (lecture hall 101 in building 2501, Callinstraße 3-9). Additionally, the researchers will post regular updates on the project website.

Stormy weather and rough seas

The Marion Rise is located approximately 2,500 kilometres to the south-east of the southern tip of Africa – in the “Roaring Forties”. The region is notorious for its fickle weather conditions, as well as frequent storms and rough seas. Overall, 35 researchers will travel aboard the 115 metre-long vessel.

In addition to Professor Koepke, one doctoral candidate as well as two master’s degree students from Leibniz University Hannover will join the expedition. The MARUM at Bremen University will be in charge of coordinating the logistics, such as transporting containers and hazardous material as well as customs handling.

The Federal Ministry of Education and Research (BMBF) has been operating RV SONNE since 2014 and provides 860,000 euros of funding for the “MARION” project. In addition to Leibniz University Hannover, project partners include work groups and individual researchers from Freie Universität Berlin, Bremen University, Friedrich-Alexander-Universität Erlangen-Nürnberg, University of Münster, University of Helsinki (Finland), Tongji University (China), Università di Modena e Reggio Emilia (Italy), as well as the American partners University of Wyoming, Florida State University and the Woods Hole Oceanographic Institution.

For further information, please contact Prof. Dr. Jürgen Koepke, Institute of Mineralogy, Tel. +49 511 762 4084 (available until 28 February 2020), Email koepke@mineralogie.uni-hannover.de. During the expedition, Professor Koepke will be available via email; VoIP interviews may be arranged upon request.

Further information on the project can be found on the expedition website www.geo.uni-hannover.de/de/expedition-marion. If you would like to use articles or photos published in the blog, please contact Dr. Mona Weyrauch from the Leibniz research centre FZ:GEO (Tel. +49 511 762 5074, Email weyrauch@geo.uni-hannover.de).