Sulphur isotopes in metamorphosed Precambrian Fe-Pb-Zn-Cu sulphides and baryte at Aggeneys and Gamsberg, South Africa

1983 ◽  
Vol 47 (345) ◽  
pp. 481-486 ◽  
Author(s):  
K. von Gehlen ◽  
H. Nielsen ◽  
I. Chunnett ◽  
A. Rozendaal
Keyword(s):  
South Africa ◽  
Amphibolite Facies ◽  
Sulphur Isotopes ◽  
Sedimentary Sequence ◽  
The West ◽  
Sulphur Isotope ◽  
Positive Side ◽  
Broken Hill ◽  
Ore Minerals ◽  
Black Mountain

AbstractSulphur isotope ratios in sulphides and baryte from stratabound and stratiform orebodies in a metavolcanic-sedimentary sequence in Namaqualand were found, in part, to be extreme for Precambrian sulphur. Black Mountain, Aggeneys, in the west gave an average for the sulphides of δ34S = +8.9±3.7‰ (9 samples), an average for barytes of +20.6±4.3‰ (3 samples). Broken Hill, Aggeneys, in the centre gave an average for the sulphides of δ34S = +19.8±3.1‰ (19 samples). Gamsberg, in the east, gave an average for the sulphides of δ34S = +29.2±1.8‰ (24 samples), and an average for barytes of +35.4±0.2‰ (2 samples). The δ34S values increase eastward. Their range is strongly on the positive side and does not centre around zero. The Gamsberg barytes and most Gamsberg sulphides have more positive δ34S values than those reported for other Precambrian sulphides and sulphates. We interpret the above sulphur isotope range as being mainly due to the varying contributions of submarine-exhalative sulphide sulphur with δ34S close to zero and bacterially(?) reduced sulphate with strongly positive δ34S, apparently from evaporites in the east. Metamorphism of amphibolite facies grade has partly isotopically re-equilibrated the ore minerals, as indicated by galena-pyrrhotine and sulphide-baryte isotope temperatures from single specimens, but has not destroyed the primary sulphur isotope range indicating pre-existing sulphate concentrations.

Zincian högbomite as an exploration guide to metamorphosed massive sulphide deposits

1989 ◽  
Vol 53 (370) ◽  
pp. 263-269 ◽  
Author(s):  
Paul G. Spry ◽  
Erich U. Petersen
Keyword(s):  
South Africa ◽  
Massive Sulphide ◽  
Oxidation Reactions ◽  
Broken Hill ◽  
Massive Sulphide Deposits ◽  
Accessory Phase ◽  
Zn Content ◽  
Sulphide Deposits ◽  
Black Mountain

AbstractZincian högbomite (ZnO 3.5–10.5wt.%) occurs as an accessory phase in garnet quartzite that is intimately associated with the Broken Hill and Black Mountain Cu-Pb-Zn-Ag deposits, Aggeneys, South Africa. Högbomite coexists with a number of minerals including quartz, gahnite, sillimanite, sphalerite, pyrrhotine, pyrite, magnetite, and ilmenite, suggesting that högbomite may have formed by sulphidation and oxidation reactions. Such reactions may account for the high Zn content of högbomite. Where associated with metamorphosed massive sulphide deposits högbomite is enriched in Zn relative to that found in ultramafics, Fe-Ti deposits, Fe ores, aluminous metasediments, and skarns. This enrichment in högbomite constitutes a potential exploration guide for metamorphosed massive sulphide deposits.

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.

Seasonal occurrence and diel calling behaviour of Antarctic blue whales and fin whales in relation to environmental conditions off the west coast of South Africa

2019 ◽  
Vol 190 ◽  
pp. 25-39 ◽  
Author(s):  
Fannie W. Shabangu ◽  
Ken P. Findlay ◽  
Dawit Yemane ◽  
Kathleen M. Stafford ◽  
Marcel van den Berg ◽  
...  
Keyword(s):  
South Africa ◽  
Environmental Conditions ◽  
West Coast ◽  
Seasonal Occurrence ◽  
The West ◽  
Calling Behaviour ◽  
Fin Whales ◽  
Blue Whales
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