UNH Ocean Seminar

Combining Law of the Sea Continental Shelf Delineation and Scientific Interests: The Case of the Demerara Plateau Offshore French Guiana and Surinam

Walter Roest


Friday, Sep. 16, 2022, 3:10pm
Chase 105

As an international scholar visiting CCOM for two months at the invitation of Larry Mayer, I would like to use this seminar as an opportunity to present a brief description of my career path and my research and related professional activities. This will allow staff and students to know more about my background and research themes. I encourage all of you to come and visit me in my office at CCOM for exchanges, because these are the whole point of my stay at UNH; my door is always open.

Follows a presentation of the French UNCLOS program EXTRAPLAC. During this program some 20 mapping cruises were carried out offshore the French mainland and its overseas territories to characterize the seabed and subsoil. We tried as much as possible to combine scientific interest in these regions, often poorly mapped and understood, with scientific research involving Master and Ph.D. students. In particular, I will discuss the example of the Demerara Plateau, offshore French Guiana and Surinam, where the initial EXTRAPLAC cruise of 2003 has led to academic collaboration and three follow-up cruises, with a fourth cruise planned for 2023.

I will conclude by stressing the opportunities for seafloor mapping that UNCLOS has provided, and by expressing some concern on the slow progress made by the Commission on the Limits of the Continental Shelf that has to examine the ECS submissions of coastal States.


Walter Roest obtained a Ph.D. in marine geophysics from the University of Utrecht in the Netherlands. After a 3-year post doc at the Atlantic Geoscience Center (Bedford Institute in Dartmouth, Nova Scotia, Canada), he worked at the Geological Survey of Canada (GSC), in Ottawa, Ontario, primarily on continental magnetic and gravity acquisition and interpretation. Over the years, he also occupied several management positions at the GSC.

In 2003, Walter was appointed director of the Marine Geosciences Department of Ifremer, the French Public Institute for Marine Research, in Brest, France. He led the French program for the extended continental shelf (ECS) in the framework of the UN Convention on the Law of the Sea from 2003 to 2012, including many mapping cruises offshore the French overseas territories. He served as a member and one of the vice-presidents of the UN Commission on the Limits of the Continental Shelf from 2012 to 2017. His research interests are in plate tectonics, fracture zones, the evolution of continental margins. He also participated actively in the development of several large-scale open access geophysical data compilations.

Walter Roest’s stay at CCOM is sparked by his interest in seafloor mapping, Seabed2030, the Map the Gaps initiative, the GEBCO/Nippon training program, as well as the ECS work in which CCOM is involved. His current research interests include:

  • The formation and evolution of continental margins, and in particular transform margins and associated transform margin plateaus, such as the Demerara Plateau offshore French Guiana and Surinam.
  • Issues related to ECS, including the interpretation of the Convention and application of the relevant provisions of its Article 76.
  • Hazards related to the large double transform fault system in the region of Haiti. He obtained the funding from the French National Fleet for a multidisciplinary research cruise, to be programmed in 2024 or 2025 (seafloor mapping, active and passive seismics and coring combined with onshore paleo seismology work).