Editing Hydrogeology of Mozambique

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!colspan="4"| Igneous
 
!colspan="4"| Igneous
 
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|Karoo volcanic rocks; Post-Karoo largely intrusive igneous rocks. Including the following formations: the volcanic Movene; Umbeluzi  (including Basalt Member); Rio Nhavudezi, Bangomatete, Rio Mazoe; and intrusive igneous Gorongosa Suite and Rukore Suite
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|Karoo volcanic rocks and Post-Karoo largely intrusive igneous rocks, including the following formations: the volcanic Movene; Umbeluzi  (including Basalt Member); Rio Nhavudezi, Bangomatete, Rio Mazoe; and intrusive igneous Gorongosa Suite and Rukore Suite
 
||Jurassic to Early Cretaceous
 
||Jurassic to Early Cretaceous
 
||The Karoo terminated with a period of intensive volcanic activity, dominated by basaltic and rhyolitic outflows, with the resulting rocks including basalt, rhyolite, andesite, tuff, ignimbrite and volcanic breccia. The volcanic sequence consists of a number of superposed lava flows, emerging from tension faults and fissures along the margins of the Basement Complex and along the widening Zambeze and Limpopo Basins. A line of outcrops is found along these margins, of which the Libombo Range in the southwest is the most important. The outcrops continue in a narrow strip to the north of the Zambeze. The basalt along the coast of Nampula province is considered to form part of the same system.  
 
||The Karoo terminated with a period of intensive volcanic activity, dominated by basaltic and rhyolitic outflows, with the resulting rocks including basalt, rhyolite, andesite, tuff, ignimbrite and volcanic breccia. The volcanic sequence consists of a number of superposed lava flows, emerging from tension faults and fissures along the margins of the Basement Complex and along the widening Zambeze and Limpopo Basins. A line of outcrops is found along these margins, of which the Libombo Range in the southwest is the most important. The outcrops continue in a narrow strip to the north of the Zambeze. The basalt along the coast of Nampula province is considered to form part of the same system.  
  
After Karoo volcanism, local, mostly intrusive, igneous activities continued along borders of the East African Rift System and the Zimbabwe and Kaapvaal Cratons. The Post-Karoo igneous phenomena are dispersed and produced rocks with a wide variety of composition, genesis and age, including granite, syenite, gabbro, feldspar porphyry and mafic dykes. The late Jurassic to early Cretaceous batholith of the Serra da Gorongosa, consisting of gabbroic and granitic rocks, and the Middle Cretaceous alkaline lavas of the Lupata region are the most important features. More dispersed examples are the Cretaceous syenitic plutons of Milange, Chiperone and Derre and the carbonatite complexes and Upper Tertiary vents of basic to ultra-basic composition in the Sena region.
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After Karoo volcanism, local igneous activities continued along borders of the East African Rift System and the Zimbabwe and Kaapvaal Cratons. The Post-Karoo igneous phenomena are dispersed and produced rocks with a wide variety of composition, genesis and age, including granite, syenite, gabbro, feldspar porphyry and mafic dykes. The late Jurassic to early Cretaceous batholith of the Serra da Gorongosa, consisting of gabbroic and granitic rocks, and the Middle Cretaceous alkaline lavas of the Lupata region are the most important features. More dispersed examples are the Cretaceous syenitic plutons of Milange, Chiperone and Derre and the carbonatite complexes and Upper Tertiary vents of basic to ultra-basic composition in the Sena region.
 
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|Low
 
|Low
|Igneous rocks in Mozambique typically form local, small and dispersed aquifers, with limited productivity and without significant groundwater resources. Weathering variable, but there can be a 10 to 20 m thick weathered mantle. Weathering in basalt terrain is often more enhanced, but here weathered material tends to be very clayey and almost impermeable. Some shallow groundwater can be found where the weathered mantle is thick enough and permeable enough, but generally primary and secondary fractures are the most important water-bearing features. Groundwater frequently appears in spring zones. The most productive areas are along fault zones, and talus slopes where weathering is enhanced.  
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||Volcanic (extrusive) rocks include phonolites, trachytes and similar rocks, rhyolites and basalts. Intrusive rocks include syenites, granites and similar rocks and gabbros and similar rocks.
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Igneous rocks in Mozambique typically form local, small and dispersed aquifers, with limited productivity and without significant groundwater resources. Weathering variable, but there can be a 10 to 20 m thick weathered mantle. Weathering in basalt terrain is often more enhanced, but here weathered material tends to be very clayey and almost impermeable. Some shallow groundwater can be found where the weathered mantle is thick enough and permeable enough, but generally primary and secondary fractures are the most important water-bearing features. Groundwater frequently appears in spring zones. The most productive areas are along fault zones, and talus slopes where weathering is enhanced.  
  
 
Typical borehole yields are less than 1 m³/hour. Where there is a well-developed, permeable weathered zone, yields from this zone can be higher, but typically not more than 3 m³/hour. Intergranular permeability is very low to zero. The aquifer is generally unconfined. Borehole depths typically vary between 30 and 100 m. Aquifer zones are typically small and dispersed, and therefore there is limited groundwater storage.
 
Typical borehole yields are less than 1 m³/hour. Where there is a well-developed, permeable weathered zone, yields from this zone can be higher, but typically not more than 3 m³/hour. Intergranular permeability is very low to zero. The aquifer is generally unconfined. Borehole depths typically vary between 30 and 100 m. Aquifer zones are typically small and dispersed, and therefore there is limited groundwater storage.

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