Ambohiby Massif is an alkaline ring complex in Tsiroanomandidy District, Bongolava, Madagascar, which covers approximately 225 km² (87 sq mi).^[2]

Quick Facts Andranomangatsiakacode: mlg promoted to code: mg (Malagasy), Location ...

Ambohiby Massif Andranomangatsiakacode: mlg promoted to code: mg  (Malagasy)
Ring complex
The massif (lower right) as seen by the Landsat 7 satellite.
Ambohiby Massif
Coordinates: 18.836°S 46.206°E / -18.836; 46.206
Location	Bongolava, Madagascar
Age	90 million years (Late Cretaceous)
Formed by	Collapse caldera event due to tectonic separation of India and Madagascar.
Native name	Andranomangatsiakacode: mlg promoted to code: mg  (Malagasy)
Area
• Total	225 square kilometres (87 sq mi)
Dimensions
• Height	1,630 metres (5,350 ft)[1]

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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, 8 km (5.0 mi) away, and the nearest city, Tsiroanomandidy, is 18 km (11 mi) away.^[3]

The massif was formed during the Late Cretaceous period, as the Madagascar Plate and the Indian Plate separated around 90 million years ago. Originally it was a volcano, 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.^[3]

According to the record from French botanist Jacques Désiré Leandri 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.^[1]

Anosibe Ambohiby, a settlement of Betsileo citrus farmers and merchants, was established on the volcano in 2008.^[3]