Great Dyke
"The Great Dyke is the longest linear mass of mafic and ultramafic rocks in the world and is the most outstanding feature of the geographical map in Zimbabwe." [1]
See Great Dyke Investments.
Mining in Zimbabwe.
History/Description
The Dyke is ±530km long, running north-south from the Mvurwi Range to around Lalapanzi in the south. It covers 3083km² and varies from 1km to 11km wide. Maximum altitude above the surrounding ground is 350m. It was first identified by Karl Maunch during explorations from 1867 to 1872.
The Great Dyke is a topographic spine down Zimbabwe's central plateau. The northern end is the Mvurwi Range, near Guruve, (the western end of the Mavuradonha Mountains) on the Zambezi River Escarpment. It can be seen south at the Darwendale Hills, then near Ngezi Dam and Machava Moutains]]. South of Lalapanzi, near Mberengwa the dyke ends as the Chironde and Doro Hills. [2]
Dyke rock is a barrier to ground water, making the edges marshy and the source of many springs and streams. Darwendale, Ngezi and Sebakwe Dams use natural sites along the dyke. The serpentinite (70 percent of the Dyke area), gabbronorite and pyroxenite rocks of the Dyke produce distinct soils that grow markedly different vegetation.
Geology
Extensive geological mapping in the 1950s showed the Dyke was four contiguous complexes. And the Dyke is part of a larger fracture system, true quartz gabbro dykes - Umvimeele Dyke to the west and East Dyke to the east. It is also not a true dike in geological terms.
The Great Dyke is an "enormous" repository of chrome and platinum. ASbestos ws mined here (Motorshanga) and there is evidence of nickel, [1] and magnesite. [3]
- ↑ 1.0 1.1 [Katherine Sayce (Ed), Tabex, Encyclopedia Zimbabwe], Tabex, Encyclopedia Zimbabwe, (Quest Publishing, Harare, 1987), Retrieved: 25 July 2019
- ↑ [R. Kent Rasmussen (ed), Historical Dictionary of Zimbabwe/Rhodesia] (The Scarecrow Press, London, 1979) Retrieved 8 August 2019"
- ↑ [Mary Akers (ed.), Encyclopaedia Rhodesia] (The College Press, Salisbury, 1973) Retrieved 8 August 2019"
