Aspects of the Precambrian tectonic evolution of Africa in the early Archaean, early Proterozoic and late Proterozoic

Abstract:

This paper reviews recent progress in the early Archaean of the eastern Kaapvaal craton, the early Proterozoic of West Africa and the late Proterozoic of northeast Africa. Tectonic styles do not differ much through earth history and reflect a dominance of horizontal deformation. Early Archaean tonalitic-trondhjemitic gneisses of the Ancient Gneiss Complex in Swaziland are partly older than adjacent greenstone belts and were themselves derived from crustal precursors. The magmatic and tectonic evolution of the upper crustal Barberton granitoid-greenstone terrain was closely related to that of the middle crustal Ancient Gneiss Complex. Terrane accretion may have played an important role in the development of greenstone and gneiss terrains. Both the ~2.3~2.0 Ga Birimian domain of West Africa and the 0.95~0.55 Ga Nubian shield (NS) for northeast Africa represent major Proterozoic additions of juvenile material to the African continent through processes of mantle melting and subsequent lateral accretion. Many high-strain zones probably mark terrane boundaries in low and high-grade terrains of all ages, and it is likely that terrane amalgamation played a major role in the orogenic evolution of Africa like in other continents. -from Author

Año de publicación:

1993

Keywords:

Fuente:

scopus