Origin and significance of noritic blocks in layered anorthosites in the Bushveld Complex, South Africa

2021 ◽  
Vol 177 (1) ◽  
Author(s):  
J. E. Bourdeau ◽  
B. Hayes ◽  
S. E. Zhang ◽  
A. Logue ◽  
G. M. Bybee
Keyword(s):  
South Africa ◽  
Bushveld Complex

Lithostratigraphy of the Palaeoproterozoic Hekpoort Formation (Pretoria Group, Transvaal Supergroup), South Africa

2020 ◽  
Vol 123 (4) ◽  
pp. 655-668
Author(s):  
N. Lenhardt ◽  
W. Altermann ◽  
F. Humbert ◽  
M. de Kock
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Sedimentary Rocks ◽  
Type Locality ◽  
Large Igneous Province ◽  
Braided River ◽  
River Systems ◽  
The West ◽  
Igneous Province ◽  
Transvaal Supergroup

Abstract The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.

Variations in Composition, Texture, and Platinum Group Element Mineralization in the Lower Group and Middle Group Chromitites of the Northwestern Bushveld Complex, South Africa

2019 ◽  
Vol 114 (3) ◽  
pp. 569-590 ◽  
Author(s):  
Felix E.D. Kaufmann ◽  
Marie C. Hoffmann ◽  
Kai Bachmann ◽  
Ilya V. Veksler ◽  
Robert B. Trumbull ◽  
...  
Keyword(s):  
South Africa ◽  
Platinum Group Element ◽  
Bushveld Complex ◽  
Group Element ◽  
Middle Group ◽  
Platinum Group ◽  
Lower Group

DETRITAL PLATINUM-GROUP MINERALS IN RIVERS DRAINING THE EASTERN BUSHVELD COMPLEX, SOUTH AFRICA

2004 ◽  
Vol 42 (2) ◽  
pp. 563-582 ◽  
Author(s):  
T. Oberthur ◽  
F. Melcher ◽  
L. Gast ◽  
C. Wohrl ◽  
J. Lodziak
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Platinum Group Minerals ◽  
Platinum Group

ALLUVIAL AND ELUVIAL PLATINUM-GROUP MINERALS FROM THE BUSHVELD COMPLEX, SOUTH AFRICA

2014 ◽  
Vol 117 (2) ◽  
pp. 255-274 ◽  
Author(s):  
T. OBERTHUR ◽  
T. W. WEISER ◽  
F. MELCHER
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Platinum Group Minerals ◽  
Platinum Group

scholarly journals Electrochemical Processes in a Crystal Mush: Cyclic Units in the Upper Critical Zone of the Bushveld Complex, South Africa

2015 ◽  
Vol 56 (6) ◽  
pp. 1229-1250 ◽  
Author(s):  
Ilya V. Veksler ◽  
David L. Reid ◽  
Peter Dulski ◽  
Jakob K. Keiding ◽  
Mathias Schannor ◽  
...  
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Critical Zone ◽  
Crystal Mush ◽  
Electrochemical Processes

New Data for Malanite and Cuprorhodsite from Chromitites of the Bushveld Complex, South Africa

2020 ◽  
Vol 62 (8) ◽  
pp. 796-802
Author(s):  
N. S. Rudashevsky ◽  
V. N. Rudashevsky
Keyword(s):  
South Africa ◽  
Bushveld Complex

Re-Os isotope and Pd/Ru variations in chromitites from the Critical Zone, Bushveld Complex, South Africa

1999 ◽  
Vol 63 (6) ◽  
pp. 911-923 ◽  
Author(s):  
Tom E. McCandless ◽  
Joaquin Ruiz ◽  
B.Ivan Adair ◽  
Claire Freydier
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Critical Zone ◽  
Os Isotope

scholarly journals The Creation and Evolution of Crystal Mush in the Upper Zone of the Rustenburg Layered Suite, Bushveld Complex, South Africa

2019 ◽  
Vol 60 (8) ◽  
pp. 1523-1542 ◽  
Author(s):  
Z Vukmanovic ◽  
M B Holness ◽  
M J Stock ◽  
R J Roberts
Keyword(s):  
South Africa ◽  
Magma Chamber ◽  
Simple Shear ◽  
Bushveld Complex ◽  
Immiscible Liquid ◽  
Textural Analysis ◽  
Crystal Nucleation ◽  
Crystal Mush ◽  
Gravitational Loading ◽  
Crystal Accumulation

Abstract The Upper Zone of the Rustenburg Layered Suite of the Bushveld Complex contains the world’s largest Fe–Ti–V ± P deposit and formed from the last major injection of magma into the chamber. Quantitative textural analysis of Upper Zone rocks was undertaken to constrain the processes operating during mush formation and solidification, focussing on horizons with the greatest density contrast to isolate the effects of gravitational loading. We examined three magnetitite layers, together with their underlying and overlying anorthosites. The similarity of microstructures in anorthosites above and below the dense magnetitite layers suggests that the rocks were not affected by viscous compaction driven by gravitational loading. The magnetitite cumulate layers formed by crystal accumulation from a mobile crystal slurry dominated by the Fe-rich conjugate of an unmixed immiscible liquid. We suggest a new mechanism of crystal nucleation in deforming crystal-rich systems, driven by undercooling caused by cavitation as grains slide past each other during simple shear. We propose that the super-solidus deformation recorded in these rocks was caused by prolonged regional subsidence of the magma chamber at Upper Zone times.

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