The Adamastor Ocean was a "proto-Atlantic" ocean that formed with the break-up of the
Rodinia
Rodinia (from the Russian родина, ''rodina'', meaning "motherland, birthplace") was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago (Ga) and broke up 750–633 million years ago (Ma). wer ...
supercontinent 780–750 . It separated the
RÃo de la Plata Craton from the
Congo Craton. The inversion of the Adamastor Ocean began about 640 Ma with the development of a large
back-arc basin
A back-arc basin is a type of geologic Structural basin, basin, found at some convergent boundary, convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found ...
along the western margin of the
Kalahari Craton, and the ocean closed when RÃo de la Plata collided with Kalahari about 545 Ma along the sinistral
Sierra Ballena Shear Zone. The
São Francisco Craton and the RÃo de la Plata Craton amalgamated 630–620 Ma, closing the Adamastor Ocean on the South American side and forming the
around 600 Ma.
In 2020 a group of geologists proposed an alternative model for the Adamastor Ocean in which it is reduced to an intracontinental rift system with only some minor oceanic crust developing in its southern part.
Etymology
South African geologist Chris Hartnady named the Precambrian ocean after the mythical giant
Adamastor from
LuÃs de Camões
LuÃs Vaz de Camões (; or 1525 – 10 June 1580), sometimes rendered in English as Camoens or Camoëns ( ), is considered Portugal's and the Portuguese language's greatest poet. His mastery of verse has been compared to that of William Shakes ...
's poem ''
Os LusÃadas
''Os LusÃadas'' (), usually translated as ''The Lusiads'', is a Portuguese epic poem written by LuÃs Vaz de Camões ( – 1580) and first published in 1572. It is widely regarded as the most important work of Portuguese-language literature ...
'' which celebrates
Vasco da Gama
Vasco da Gama ( , ; – 24 December 1524), was a Portuguese explorer and nobleman who was the Portuguese discovery of the sea route to India, first European to reach India by sea.
Da Gama's first voyage (1497–1499) was the first to link ...
's discovery of the sea route to India. Hartnady thought it an appropriate name since the demigod was transformed into stone and personified the
Cape of Storms and since
Atlas
An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets.
Atlases have traditio ...
and
Iapetus
In Greek mythology, Iapetus (; ; ), also Japetus, is a Titan, the son of Uranus and Gaia and father of Atlas, Prometheus, Epimetheus, and Menoetius. He was also called the father of Buphagus and Anchiale in other sources.
Iapetus was linked ...
are associated with the oceans of the northern Atlantic, the North Atlantic Ocean and the
Iapetus Ocean respectively.
Geological history
The Adamastor Ocean was narrow in the north, perhaps similar to the Red Sea, but widened southward.
Carbon isotope analyses indicate that the ocean water was strongly stratified and thus that it must have been a closed ocean, similar to the Mediterranean, but probably covered by ice during the
Sturtian and
Marinoan glaciations.
Ocean floor adjacent to the
Marmora Terrane (near the
Orange River
The Orange River (from Afrikaans/Dutch language, Dutch: ''Oranjerivier'') is a river in Southern Africa. It is the longest river in South Africa. With a total length of , the Orange River Basin extends from Lesotho into South Africa and Namibi ...
in South Africa) formed 740–580 Ma, dates that represent the first rifting and the first accretion respectively. The Adamastor Ocean closed in three episodes: the RÃo de la Plata Craton first collided with the Congo Craton, which then collided with the Kalahari Craton, which finally collided with RÃo de la Plata.
See also
*
Brasiliano orogeny
Brasiliano orogeny or Brasiliano cycle ( and ''Ciclo Brasiliano'') refers to a series of orogenies from the Neoproterozoic era, exposed chiefly in Brazil but also in other parts of South America. The Brasiliano orogeny is a regional name for the l ...
*
Geology of Namibia
References
Notes
Sources
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{{Refend
Historical oceans
Precambrian Africa
Precambrian South America