A Discussion on the evolution of the Precambrian crust - The Limpopo mobile belt — Southern Africa

1973 ◽  
Vol 273 (1235) ◽  
pp. 463-485 ◽  
Keyword(s):  
Shear Deformation ◽  
Southern Africa ◽  
Central Zone ◽  
Kaapvaal Craton ◽  
Mobile Belt ◽  
High Grade ◽  
The South ◽  
Geological Time ◽  
The North ◽  
Limpopo Belt

The Limpopo belt is an extensive ENE-trending linear zone of high-grade metamorphic tectonites which separates the Archaean nucleii of the Rhodesian craton to the north from the Kaapvaal craton to the south. The belt consists of reworked Archaean granite-greenstone terrain with an early Proterozoic cover sequence, the Messina Formation, infolded and metamorphosed with the basement. Two major zones of shearing and transcurrent dislocation separate marginal granulite zones from a central zone which consists of complexly infolded cover rocks and reworked basement. The northern granulite zone appears to grade transitionally into the Rhodesian craton to the north, whereas there is some evidence that the southern granulite zone is faulted against the Kaapvaal craton to the south. The whole belt has behaved as a zone of crustal weakness throughout geological time, and is characterized by repeated shear deformation, igneous intrusion and extrusion, despite the cessation of major regional tectono-thermal reactivation about 1900 Ma ago.

A terrane interpretation of the Archaean Limpopo Belt

1993 ◽  
Vol 130 (6) ◽  
pp. 755-765 ◽  
Author(s):  
H. R. Rollinson
Keyword(s):  
Shear Zones ◽  
Kaapvaal Craton ◽  
Late Archaean ◽  
The North ◽  
Zimbabwe Craton ◽  
Marginal Zones ◽  
Limpopo Belt

AbstractThe Limpopo Belt is a zone of thickened Archaean crust whose origin is currently explained by a late Archaean continent-continent collision between the Kaapvaal and Zimbabwe cratons. This review shows that the two cratons have fundamentally different geological histories and that the Zimbabwe Craton was unlikely to have behaved as a stable ‘cratonic’ block at the time of the Limpopo Belt collision. The geological histories of the Zimbabwe Craton, the North Marginal, Central and South Marginal zones of the Limpopo Belt and the Kaapvaal Craton are shown to be sufficiently different from one another to warrant their consideration as discrete terranes. The boundaries between the five units outlined above are all major shear zones, further supporting a terrane model for the Limpopo Belt. The five units were all intruded by late- to syn-tectonic granites c.2.6 Ga, constraining the accretion event to c. 2.6 Ga.

A new leafhopper genus Geelus and 12 new species (Hemiptera, Cicadellidae, Deltocephalinae) from Southern Africa 

Zootaxa ◽  
2020 ◽  
Vol 4786 (3) ◽  
pp. 301-344 ◽  
Author(s):  
MICHAEL STILLER
Keyword(s):  
South Africa ◽  
New Species ◽  
Southern Africa ◽  
New Genus ◽  
Dorsal Side ◽  
Distribution Model ◽  
The South ◽  
African Species ◽  
The North ◽  
Bioclimatic Variables

Twelve new species in a new genus, Geelus gen.n. are described, 10 species from a confined area in the north- and south-western parts of South Africa and two from Namibia. The genus has been recorded from 35 plant species in 18 families, with one species Geelus dundraad collected on Rooibos Tea, Aspalathus linearis (Fabaceae), which is indigenous to South Africa and cultivated commercially. The 12 new species are Geelus driehoekdraad sp.n., G. drietanddraad sp.n., G. dundraad sp.n., G. haakdraad sp.n., G. kinkeldraad sp.n., G. lemdraad sp.n., G. nektanddraad sp.n., G. platdraad sp.n., G. slangdraad sp.n., G. stompdraad sp.n., G. viertanddraad and G. vurkdraad sp.n. This new genus is allied to the Bonaspeiini, in the Deltocephalinae based on the broad lorum, apically expanded clypellus, dorsal side of the pygofer deeply and broadly incised, large sclerotized segment X, smooth merging of face and crown and Y-shaped connective with short stem. A MaxEnt distribution model based on 19 bioclimatic variables confirmed that the South African species occur within a confined region in the south-western parts of southern Africa. 

scholarly journals Chemical data on some rock-forming minerals from high-grade gneisses, amphibolites and anorthosites from the Fiskenæsset area

1971 ◽  
Vol 35 ◽  
pp. 22-23
Author(s):  
T Frisch
Keyword(s):  
Rock Type ◽  
Amphibolite Facies ◽  
Chemical Data ◽  
High Grade ◽  
Boundary Zone ◽  
Areal Extent ◽  
Common Occurrence ◽  
The South ◽  
The West ◽  
The North

The area mapped by the writer is situated to the west of Fiskenæsset and lies in the boundary zone between granulite and amphibolite facies rocks (see Kalsbeek, this report). In the north a creamy- to pink-weathering gneiss, commonly containing hypersthene and biotite is the chief rock type. In the south small-folded, pale-grey weathering biotite-hornblende gneisses are predominant. Amphibolite is of common occurrence in layers, pods and agmatite. The areal extent of the anorthosite-pyribolite complex as previously outlined by reconnaissance mapping (Ghisler & Windley, 1967) was confirmed in general but modified in detail. Additional occurrences of rocks belonging to the complex were found.

scholarly journals The Proterozoic mobile belt in the Ammassalik region, South-East Greenland (Ammassalik mobile belt): an introduction and re-appraisal

1989 ◽  
Vol 146 ◽  
pp. 5-12
Author(s):  
B Chadwick ◽  
P.R Dawes ◽  
J.C Escher ◽  
C.R.L Friend ◽  
R.P Hall ◽  
...  
Keyword(s):  
Shear Zones ◽  
Granulite Facies ◽  
Mobile Belt ◽  
The South ◽  
Southern Limit ◽  
Late Archaean ◽  
Early Proterozoic ◽  
The North ◽  
Layer Cake ◽  
Dyke Swarms

The Ammassalik mobile belt is characterised by a regional layer cake structure of tectonically interleaved sheets of quartzo-feldspathic orthogneisses and supracrustal rocks. The sheets of supracrustal rocks are most abundant in the north of the belt and they include semi-pelitic kyanite-sillimanite gneisses, graphitic schists, marble, amphibolites and local peridotite. The sheets are regarded as parts of a disrupted supracrustal sequence, here termed the Siportoq supracrustal association. Preliminary isotopic age data suggest that most of the orthogneisses are late Archaean, although some have early Proterozoic ages. The Siportoq supracrustal association has yielded an early Proterozoic age. Amphibolite dyke swarms were emplaced at various stages in the evolution of the mobile belt. The Ammassalik belt has an ill-defined northern limit marked by heterogeneous retrogression of a granulite facies terrain up to 100 km wide. Most of the belt is at amphibolite facies, with its southern limit lying to the south of the area considered here. The structure in the south is dominated by nappes and shear zones dipping NE within a wide tract of late Archaean orthogneisses intruded by amphibolite dyke swarms with relatively well preserved primary characteristics. The structure in the north is characterised by more pervasive deformation which gave rise to complex sequences of thrusting and nappe development propagating from the north. Large domes were superimposed on the nappe pile, perhaps as buoyancy phenomena. The dioritic Ammassalik Intrusive Complex (c. 1885 Ma) with its granulite facies assemblages is regarded as a late kinematic phenomenon. Major post-tectonic complexes of granite, diorite and gabbro (c. 1580 Ma) were intruded at a high level well after the close of the tectonism in the Ammassalik mobile belt.

Studies in the genus Riccia (Marchantiales) from southern Africa. 7. R. congoana and its synonyms

Bothalia ◽  
1986 ◽  
Vol 16 (2) ◽  
pp. 193-201 ◽  
Author(s):  
S. M. Perold
Keyword(s):  
Sierra Leone ◽  
Southern Africa ◽  
Wide Distribution ◽  
The South ◽  
The West ◽  
The North

R. congoana Steph. is described and illustrated.  R. rhodesiae S. Arnell.  R. nigrosquarnata E. W. Jones and  R. aegyptiaca S. Arnell are treated as synonyms under R. congoana.  R. congoana has a wide distribution in Africa,  ranging from Egypt in the north to SWA/Namibia and Transvaal in the south, and from Sierra Leone in the west to Tanzania in the east.

Sign in / Sign up

Export Citation Format

Share Document