Volcanoes of Mozambique
Monte Muambe is a volcanic caldera located southeast of Moatize in Mozambique. It is ring-shaped and formed from Karoo sandstone, rising from flat ground at about 250–300 m. The caldera rim is a circular ridge about 500 m above the surrounding plain. Erosion has left a crater-like hollow inside, and the very center sits roughly 200 m lower than the rim.
The area lies on the southern edge of the ancient Tete gabbro-diorite crust. In the Mesozoic era, Karoo sediments and volcanic rocks filled the caldera depression.
The rocks form an east–west belt that gently dips toward the southeast. The sequence runs from older rocks in the north to younger rocks in the south. The oldest units include Tilitos and Produtiva series with coal; they are followed by fossil-bearing sandstones and clay layers.
The Stromberg volcanic series in the region includes amygdaloid basalts (lava flows) and basalt dykes. After the Karoo rocks, younger deposits appear as Lupata Series sandstones and volcanic rocks; Monte Muambe contains Upper Lupata Sandstones. This Lupata group includes sandstones and alkali lava; intrusive rocks include syenite and carbonatite.
The Lupata region is about 10 km southeast, near Chincongolo and Lupata Gorge, and features Upper Lupata Sandstones, syenite, carbonatites, and alkaline extrusive rocks.
In Monte Muambe, the sequence includes coarse sandstones overlain by basalts and agglomerates made of Karoo debris plus carbonatite bombs, with alkali lava flows forming tabular bodies.
The Lupata Series spans from the Lower Jurassic to the Lower Cretaceous. Monte Muambe is part of the East African Rift volcanic system and represents an extinct carbonatite volcano. The caldera floor is about 5 km across and contains carbonatite, agglomerate, tuff, fenites, and basic dykes; the outer rim is mostly feldspathic rocks with little carbonatite. The central area is a dissected carbonatite mass about 200 m lower than the surrounding Karroo ridge.
Fenites are rocks altered by alkalis around carbonatite. Later hydrothermal activity formed mineral resources in carbonatites and fenites.
This page was last edited on 3 February 2026, at 10:02 (CET).