Continental shelf: how boundaries have been redrawn for expansion

Since late March 2017, a United Nations Scientific Committee has approved Argentina's request to expand its underwater platform in accordance with the regime established by the United Nations Convention on the Law of the Sea (Convemar, 2004). one of the most important multilateral event treaties, signed by 168 states), the country has extended its submarine borders by about 35%.

The new boundary has added nearly 1,800,000 km2, adding to the current 4,200,000, which has allowed the exclusive zone of exploration and exploitation of the sea floor and subsoil to exceed 6,000 000 km2.

"Almost another Argentina has been added," says engineer Marcelo Paterlini, professor at the Faculty of Marine Sciences and coordinator of the team of geologists, geodetectors, geophysicists, hydrographers, seismologists, cartographers, oceanographers and Geographic Information Systems Analysts who Over the decade, studies were conducted to corroborate the presentation, which was then badyzed and reviewed for eight years, until its approval. – The Argentine delegation held more than 30 meetings with the United Nations Subcommittee on Auditing to determine whether it was in line with the objectives. This new route borders the ocean waters, heritage of humanity, of all the inhabitants of this planet. "

Throughout the 20th century, coastal states have proposed expanding the territorial sea to protect fish and mineral resources and to implement control measures to prevent pollution. In the 1980s, the United Nations Conference on the Rights of the Sea decided to go forward in this area and, among other agencies, the panel's badysis of the platform was created, composed of 21 experts (including Paterlini). impartiality of the different regions, who would be responsible for the evaluation of the presentations.

In 1997, the National Commission for the Continental Limit of the Continental Shelf (Copla) was created in the country. It brings together a large group of experts and benefits from the collaboration of specialists from many public bodies and universities.

"We have been compiling the data for more than six years," explains the PhD in geodesy and geophysics María Alejandra Arecco, professor at the faculty of engineering of the UBA. , badysis of marine currents, mathematical badyzes on the seabed to determine the foot of the slope, the gravity, the magnetism … If the ocean was a person, we could say that we made the complete clinical history ".

Kilometers of data

To fulfill this task, oceanographic vessels with a wide variety of instruments were essential. And he did not hesitate to ask the collaboration of scientific ships from other countries that plowed our waters and could provide bathymetric information (on the depths). Some studies, such as seismic, have been acquired from foreign research institutes.

As the key criterion for determining the new limit was the "foot of slope" (ie the point at which the speed of variation of the slope that connects the continental shelf to the abyssal plain is maximal and whose determination is obtained from mathematical equations), it was necessary to conduct seismic surveys to determine "sediment thickness".

"Just as a house accumulates more dust in the corners," says Arecco, "so are the sediments located at the bottom of the oceans." At the foot of the slope, a great sedimentary thickness has accumulated, but moving towards the east, this thickness decreases, the limit has been placed where the thickness is the thinnest. "

To get an idea of ​​the amount of information to be processed, just mention that there were 106,000 km of marine depth data, 28,000 km of gravimetry, 31,600 km of magnetometry and 29,000 km seismic reflection. In total, Copla has requested 12 oceanographic campaigns.

The geodestes were responsible for determining distances taking into account the Earth's curvature and providing measurements with the precision required by the Convemar.

"Our presentation was one of the most detailed and comprehensive, very accurate in measurements and extremely rigorous in every process," says Arecco.

The continental shelf is the bed and sub-surface of the submarine areas that extend beyond the territorial sea to the new limit defined by the country and accepted by the Plateau Boundary Commission. continental United Nations. Not all countries can extend it because not all coastlines have it.

"We have one of the largest in the world," says Arecco.

With the new limit, are reserved for Argentina the exploration and exploitation of all the resources, living or not, which rest on the seabed or which are in the basement of all the region. And although what is known as "innocent transit" is allowed, ships wishing to search the area must apply for authorization.

The country has made a comprehensive presentation: from the Rio de la Plata to the Weddell Sea in Antarctica, but within this perimeter, two areas remain unresolved. "The countries that have signed the Antarctic Treaty have raised an objection and the United Kingdom has presented an objection concerning the border region of the Malvinas Islands, Georgia and South Sandwich – explains Arecco – Given this situation Convemar should not settle its differences In areas where countries are fighting for territory, the badysis remains unresolved until countries reach an agreement. "

After approval, it now remains to extend this new frontier in the form of maps, nautical charts and geography books. "We have to work hard in schools to make the new boundaries known," Paterlini concludes.