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Mauritia was a
Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...
microcontinent Continental crustal fragments, partly synonymous with microcontinents, are pieces of continents that have broken off from main continental masses to form distinct islands that are often several hundred kilometers from their place of origin. Caus ...
that was situated between
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
and
Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
until their separation about 70 million years ago. Being initially attached to the Indian continent, Mauritia separated from it about 60 million years ago and further fragmented into a ribbon-like structure as the
mid-ocean ridge A mid-ocean ridge (MOR) is a undersea mountain range, seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading ...
jumped several times. The jumps of the mid-ocean ridge are thought to have been caused of its interaction with the
Réunion hotspot The Réunion hotspot is a volcanic hotspot which currently lies under the island of Réunion in the Indian Ocean. The Chagos-Laccadive Ridge and the southern part of the Mascarene Plateau are volcanic traces of the Réunion hotspot. The hotspo ...
as it passed under the West margin of the Indian continent and then under Mauritia. As of today, the fragments of Mauritia include the Laccadives–Maldives–Chagos Ridge,
Nazareth Bank Nazareth Bank is a large submerged bank in the Indian Ocean. Geography It lies about 1,040 km east of northern Madagascar and 280 km south of the Saya de Malha Bank. The closest land is Cargados Carajos shoals, a small and remote dependency of ...
, the Saya de Malha Bank, and Hawkins Bank, as well as the islands of
Réunion Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the isl ...
and
Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...
, where the continual crust is buried under basaltic lavas of the Réunion hotspot. Evidence for Mauritia's existence consists of detrital
zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of th ...
found in rock (6-million-year-old
trachyte Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanite, aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrus ...
) on Mauritius. Analyses of the zircon crystals produced dates between 660 and 1,970 million years and are considerably older than the 8.9-million-year-old
basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
that constitutes the oldest formations on the island. The zircons are interpreted to have been brought up from buried
continental crust Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as '' continental shelves''. This layer is sometimes called '' si ...
as fragments entrained as xenocrysts within the basalt. Interpretation of a linear northwest–southeast gravity anomaly indicates the microcontinent may extend from
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...
to Mauritius roughly parallel to the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
oceanic ridge.


See also

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References

{{Submerged landmasses Continental fragments Plateaus of the Indian Ocean Historical continents Volcanism of the Indian Ocean Geography of Madagascar Geography of Mauritius Geography of Seychelles