Geochemistry of bedded barite of the Mesoproterozoic Aggeneys-Gamsberg Broken Hill-type district, South Africa

2007 ◽  
Vol 42 (5) ◽  
pp. 537-549 ◽  
Author(s):  
Craig R. McClung ◽  
Jens Gutzmer ◽  
Nicolas J. Beukes ◽  
Klaus Mezger ◽  
Harald Strauss ◽  
...  
Keyword(s):  
1983 ◽  
Vol 47 (345) ◽  
pp. 481-486 ◽  
Author(s):  
K. von Gehlen ◽  
H. Nielsen ◽  
I. Chunnett ◽  
A. Rozendaal

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.


Terra Nova ◽  
2020 ◽  
Author(s):  
Stefan Höhn ◽  
Hartwig E. Frimmel ◽  
Vinciane Debaille ◽  
Westley Price
Keyword(s):  

1916 ◽  
Vol 7 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Ll. Lloyd

The following report deals with the investigation into the bionomics of Glossina morsitans being carried out in Northern Rhodesia on behalf of the British South Africa Company.On my return from leave in July 1914 it was decided to form a base camp close to the railway line. Several areas in the neighbourhood of Broken Hill where fly was reported as being very thick were first examined, but were found from various causes to be unsuitable. A site was finally selected at the source of the Lukanga River, about four miles from the line and near Kashitu station, midway between Broken Hill and Ndola. Building was commenced in August and completed in October, just before the commencement of the rains.Messrs. Eminson and Dollman, who had been working on the Kafue River at Mwengwa, had just reported the discovery of Mutilla glossinae, Turner, a wasp parasitic on the pupae of G. morsitans and of considerable importance, since the former worker found that about 10 per cent, of the 350 pupae he had collected were destroyed by this insect. This is the first insect parasite of any tsetse to be found in numbers, and it was decided to let the future investigations centralise round it. In order to discover whether it was localised or generally distributed, a tour was made through the fly areas of N.E. Rhodesia during the dry season of last year (1915) for the collection of pupae in various localities. About 4,000 were collected and examined. May and July were spent at Chutika (Hargreaves) in the Luangwa Valley, part of August at Nawalia in the Mpika section of the same valley, and September at Ngoa on the plateau near Mpika. Breeding was found to have commenced in the Luangwa Valley about the middle of April, and by the time the plateau was reached it was at its height. Before dealing with the parasites found, some general questions will be discussed.


1914 ◽  
Vol 5 (1) ◽  
pp. 91-93
Author(s):  
Ernest E. Austen

The Imperial Bureau of Entomology has recently received from Mr. Ll. Lloyd, Entomologist to the British South Africa Company in Northern Rhodesia, a small Bombyliid fly accompanied by the following letter, dated “Mwengwa, Mumbwa, viâ Broken Hill, N. Rhodesia, November 1, 1913.—I am sending you herewith a specimen of a Dipteron, which I believe to be a parasite of G. morsitans. During July and August of this year I collected about 700 pupae of this Tsetse in nature at Ngoa, in the Mpika Division of Northern Rhodesia. These were kept under observation until September 15th, when I was compelled to travel through fly-free country for a month; they were accordingly closed up in a fly-proof case to avoid escape (in case of possible fracture of one or more of the bottles containing the pupae), and were not examined again until October 18th. On this date one of the bottles, which had contained five Tsetse pupae collected on July 21st, was found to contain:—


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