Natural delimitation between the Pacific and South Atlantic oceans by the Scotia Arc

[2] It was based on scientific studies that showed a correlation between the characteristics of the waters of the southeastern Pacific Ocean and those bounded by the Scotia Arc to the east and the Drake Passage to the west, an area known as the Scotia Sea and sometimes also as the Austral Zone Sea (the name that Argentina and Chile agreed to give to the maritime space of undefined limits to the south of the Big Island of Tierra del Fuego, which was the object of delimitation by the Treaty of Peace and Friendship signed by both countries in 1984).

Equivalences are presented in all the variables analyzed, showing similar attributes in biological (e.g. flora and marine fauna), geomorphological (e.g. depth, type, and form of substrates), and hydrographic (temperature, color, viscosity, density, and salinity).

Regarding tides, those of the southwestern South Atlantic, such as Río Grande on the Big Island of Tierra del Fuego, are commonly of great tidal amplitude, of the order of 12 to 15 metres (39 to 49 ft) and even more.

[3] Therefore, Chile argued that the coasts of the southern islands Grande de Tierra del Fuego and States were bathed in waters belonging to the Pacific, counteracting Argentina's thesis in the bioceanic principle, which had been proposed as part of a doctrine to determine the maritime boundaries between the two countries in international law.

A competing and also scientifically valid boundary between the two oceans was put forward by the researchers Juan Ignacio Ipinza Mayor and Cedomir Marangunic Damianovic, who suggested that separation of the Pacific and Atlantic oceans could be delimited by the Shackleton fracture zone, a natural submarine fault line and mid-ocean ridge, and the tectonic boundary between the Scotia plate and the Antarctic plate, which runs northwest to southeast across the Drake Passage in a roughly straight line from the southern tip of the South American continental shelf to the South Shetland Islands.

Schematic map showing the proposal presented by the thesis of the natural delimitation between the Pacific and South Atlantic oceans by the Scotia Arc
Conventional Pacific Ocean according to the IHO
Conventional Pacific Ocean according to the IHO, which become part of the Antarctic Ocean
Sector of the conventional Atlantic Ocean (according to the IHO) that would belong to the Pacific according to this theory
Sector of the conventional Atlantic Ocean (according to the IHO) that would belong to the Pacific according to this theory, which become part of the Antarctic Ocean
Conventional Atlantic Ocean (according to the IHO)
Sector of the conventional Atlantic Ocean (according to the IHO) which become part of the Antarctic Ocean
Scotia Arc, the boundary between the Pacific and South Atlantic oceans according to this thesis