Geology of Mozambique
The geology of Mozambique is primarily extremely old
Stratigraphy, Tectonics & Geologic History
The oldest rocks in Mozambique are part of the
.The schist of the greenstone belt is divided between the Manica Group, Gairezi Group and Umkondo Group, which together are the oldest individual rock units in the country. The formation of these schists and the Irumide Belt is tied to the Irumide orogeny about 1.35 billion years ago.[2]
Proterozoic (2.5 billion-539 million years ago)
During the
Phanerozoic (539 million-present)
As the Pan-African orogeny continued, in parallel with the proliferation of multi-cellular life, a large rift formed across the south of the supercontinent Gondwana across what is now South Africa and southern South America. The Karoo Supergroup, the most widely dispersed stratigraphic unit in southern Africa formed from the Carboniferous through the Early Jurassic in the Mesozoic. The Alto Zambezi Basin, Rio Lunho Basin and Rio Lugenda Basin, large intracratonal basins in Mozambique filled with sedimentary rocks. For the most part, the basins contain sequences of fluvial and glacial sediments, with layers of red mudstone with fossils and some coal layers. The Alto Zambezi Basin is capped by volcanic basalt and rhyolite in the south. Sedimentary rock formation continued in Mozambique along the coasts in the Jurassic, Cretaceous and into the Paleogene and Neogene periods of the Cenozoic, with some sedimentary units formed in the past 2.5 million years of the Quaternary. Sedimentation shifted to different basins, including the Mozambique Basin, Limpopo Basin, Baixa Zambezi Basin and Rovuma Basin.[3]
Hydrogeology
South of the
Marine and continental sandstones dominate deeper Cretaceous-Paleogene sedimentary aquifers and some also contain layers of limestone. These underlying rocks in the Mozambique Basin form the largest aquifer, beneath 21% of the country. Cut by large river valleys, arkosic sandstones give way to limestone closer to the coast. North of the Save River, the basin is moderately productive, but to the south it has high salinity nearly unusable groundwater for much of its extent. The Rovuma Basin is poorly studied, but impermeable marl and high incidences of brackish groundwater suggest it would not be a major potential source. As much as 57% of Mozambique is directly underlain by Precambrian basement rock, which forms some small and locally productive aquifers in weathered rock near the surface. Mountain areas tend to have thicker weathered mantle, with most productive locations near fault zones. In northern Mozambique, average weathered rock cover is less than 20 meters thick, rising to as much as 50 meters in valleys. Fractured volcanic rocks form locally productive aquifers, producing high quality water, often in 10 to 20 meter thick weathered rock near the surface. However, weathered basalt often ends up with high clay concentrations, limiting productivity.[4]
Natural resource geology
Mozambique has extensive natural resources, although most remain undeveloped. The Manica Belt is a continuation of the Mutare-Manica Gold Belt from Zimbabwe and contains iron, copper, asbestos, gold, lead and nickel hosted in an Archean and Paleoproterozoic greenstone belt. Small mines in the region have targeted placer gold in sediments in the area and there is also a small, high-grade bauxite deposit. The metasediments of Gairezi Group and Umkondo Group both host limestone, copper and iron near the border with Zimbabwe. Mozambique has four asbestos deposits. One has
The
References
- ^ Schlüter, Thomas (2008). Geological Atlas of Africa. Springer. pp. 180–183.
- ^ a b Schlüter 2008, p. 180.
- ^ Schlüter 2008, pp. 180–182.
- ^ "Hydrogeology of Mozambique". British Geological Survey.
- ^ Schlüter 2008, pp. 182–183.