Ambohiby Massif is an

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

ring complex in Tsiroanomandidy District, Bongolava,

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 ...

, which covers approximately . The settlement of Anosibe Ambohiby, which has a population of about 300 Betsileo people, is located within the complex almost entirely isolated from the rest of the region; the closest settlement is the town of Antaniditra, away, and the nearest city, Tsiroanomandidy, is away.

History

The

massif A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an ...

was formed during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

period, as the Madagascar Plate and the Indian Plate separated around 90 million years ago. Originally it was a

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

, however as the tectonic plates separated, the hotspot supplying it was cut off, causing the volcano to cool and collapse as it had no heat source. According to the record from French botanist

Jacques Désiré Leandri Jacques Désiré Leandri, born 1903 in Corsica, died 1982, was a French botanist and mycologist. Leandri is remembered for botanical excursions in North Africa (Morocco) and Madagascar. He collected plants for scientific study from the years ...

published in 1935, the crater was called 'Andranomangatsiaka' (translating to 'at the place of cold water'), not to be confused with the current namesake down south, by the area's indigenous people. Leandri also described the massif as having two peaks which dominate it, one called Andapa which was used as a geodetic point. He also said that the western part of the wooded region is named Ampihirano. Anosibe Ambohiby, a settlement of Betsileo

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

farmers and merchants, was established on the volcano in 2008.

References

Bongolava Landforms of Madagascar Late Cretaceous Africa Ring dikes {{volcanology-stub