Metamorphism of shales in the Witwatersrand goldfields

  • 25 Pages
  • 1.91 MB
  • English
, Johannesburg
Gold - South A
The Physical Object
Pagination25 p.
ID Numbers
Open LibraryOL22047447M

Chemical contribution of gold to the Witwatersrand shales at the sedimentary stage. The gold distribution pattern in the regionally persistent shales is significantly different within 1 to 3 m of overlying reefs.

Samples of Booysens Shale collected within i m of the overlying Kimberley reef at the Crown mine has 10 to ppb Au,File Size: KB.

The silicate mineral assemblages suggest near-uniform peak metamorphic conditions equivalent to the chlorite zone in all the major Witwatersrand gold fields.

Assemblages of coexisting pyrophyllite-chloritoid have been recorded in most of the gold mines, and the critical assemblage of pyrophyllite-chloritoid-muscovite-chlorite-quartz-tourmaline-rutile-pyrite is found in most gold by: "The Witwatersrand Gold Fields: Part II.

An Origin for Witwatersrand Gold during Metamorphism and Associated Alteration", The Geology of Gold Deposits: The Perspective inReid R.

Keays, W. Ramsay, David I. Groves. The Mesoarchaean Witwatersrand Basin represents the largest known gold anomaly and has produced more gold than any other ore province in the world.

Details Metamorphism of shales in the Witwatersrand goldfields EPUB

Deposition of the predominantly siliciclastic basin Cited by: 2. The maximum metamorphic grade in West Rand Group shales from three boreholes to the east and south of the Vredefort Dome is lower greenschist facies. In most samples the peak metamorphic assemblage consists of quartz + muscovite + chlorite, with the phyllosilicates defining a tectonic cleavage.

In many of the samples more coarsely crystalline alteration zones that clearly. The Witwatersrand gold fields of South Africa account for more than a third of the world's total gold production since mining started there in 48, t Au.

These gold fields dominated production throughout the twentieth century, but production peaked at. Goldfields extend for km around the margin of the Archaean Witwatersrand Basin of South Africa associated with regional greenschist facies metamorphism and deformation.

The regionally persistent shales (e.g. Water Tower Shale, Promise, Coronation, Jeppestown Shale, Booysens Shale) are common to many of the goldfields and intervening areas, whereas the reef package shales (e.g.

Black Bar, Green Bar, K8 shale, Khaki shale) are important in one goldfield but correlation between goldfields has a high degree of uncertainty. Geophysical methods of exploration are discussed briefly.

Description Metamorphism of shales in the Witwatersrand goldfields EPUB

The Witwatersrand Basin was formed in response to a series of crustal plate movements from the north and west in a foreland basin setting. The wide distribution of chloritoid and pyrophyllite in metapelites of the Witwatersrand Basin is attributed to alteration of chlorite‐rich shales, rather than to unusual premetamorphic.

Goldfields extend for km around the margin of the Archaean Witwatersrand Basin of South Africa associated with regional greenschist facies metamorphism and deformation.

Metamorphic mineral assemblages involving pyrophyllite-chloritoid are associated with gold in all goldfields, reflecting low pressure and to °C conditions, and.

Phillips GN, Myers RE () The Witwatersrand goldfields. An origin for Witwatersrand gold during metamorphism and associated alteration. Monogr Econ Geol 6: – Phillips GN, Law JDM, Stevens G (a) Alteration, heat and Witwatersrand gold: years after Harrison and Langlaagte. S Afr J Geol – Google Scholar.

Post-Transvaal Structural Features of the Northern Portion of the Witwatersrand Basin. Information Circular No G. Phillips. Metamorphism of Shales in the Witwatersrand Goldfields.

Information Circular No H. de la R. Winter. A Cratonic-Foreland Model for Witwatersrand Basin-Development in a Continental, Back-Arc, Plate-Tectonic. Shale is a sedimentary rock, which has a varied chemical composition, and it contains platy clay minerals that can align to pressure (associated with regional metamorphism).

Low-grade metamorphism (low pressure and temperature) of shale forms slate. Goldfields Revisited, by Edward p.

Mathers, F.R.G.S. Many other books on early Johannesburg. Recollections of Adventures, by Harry Struben. The Fred Struben diaries, at Wits University and the Oppenheimer Library. Google Earth. My own observations on the ground, on my own and while guiding tourists, and researching this paper.

Thermal properties of stratified rocks from Witwatersrand gold mining areas quartzite and conglomerate, with one prominent shale unit being developed locally. In some goldfields, the Witwatersrand succession is capped by the Venterspost Formation, a thin layer of quartzite and conglomerate (the Ventersdorp Contact Reef), which has not formally been.

The hangingwall of the CL consists of a siliceous grey quartzite overlain by the Green Bar, a chloritoid shale occurring over most of the Witwatersrand Basin. The multiple band CL facies is defined sedimentologically as a reef containing more than one conglomerate band separated by.

The Witwatersrand Basin is a largely underground geological formation which surfaces in the Witwatersrand, South holds the world's largest known gold reserves and has produced over billion ounces (o metric tons), which represents about 22% of all the gold accounted for above the surface.

The basin straddles the old provinces of Transvaal and the Orange Free State, and. Goldfields Mining, Orezone Resources Inc, AMIRA P sponsors, University of Ouagadougou, and the University of the Witwatersrand. I would like to thank AngloGold Ashanti for making the field trip possible by.

Labour, Townships & Protest: Studies In The Social History Of The Witwatersrand. Metamorphism Of Shales: In The Witwatersrand Goldfields by G Phillips.

Militants Or Proletarians?: The Economic Culture Of Underground Gold Miners In Southern Ghana, by Don Robotham. Mother Is Gold: A Study In West African Literature by Adrian Roscoe. Abstract— Historically, there have been a range of diameter estimates for the large, deeply eroded Vredefort impact structure within the Witwatersrand Basin, South Africa.

Here, we. 0BREGIONAL LOCAL 1Borogenic burial ocean-floor hydrothermal contact dislocation impact hot-slab combustion lightning pyrometamorphism Fig. Main types of metamorphism Regional metamorphism is a type of metamorphism which occu rs over an area of wide extent, that is, affecting a large rock vo lume, and is associated with large-scale tectonic processes, such.

Damang Gold Mine is owned and operated by Abosso Goldfields Limited (AGL), a Ghanaian-registered company. With Gold Fields’ acquisition of IAMGold’s indirect % stake in the Damang Gold Mine in JuneGold Fields now owns 90% of the issued shares of AGL with the Ghanaian government owning the remaining 10% free carried interest.

The. The Witwatersrand gold deposit is the largest in the world. Thermodynamic calculations show that such rich accumulations of gold could be linked to abundant volcanism, primitive life and the. By far the most gold that has been mined in South Africa (98%) has come come from the Witwatersrand goldfields.

The name "Witwatersrand" is Afrikaans (originating out of Dutch, French and German) for "White Waters Ridge". The name was derived from the white quartzite ridge which strikes parallel to the edge of the basin in which the sediment.

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The Witwatersrand is a large basin of metamorphosed conglomerates that forms the greatest goldfield in the world. It stretches for km long by km wide with a thickness that can excm.

The mines have reached depths of m. It occurs in several provinces of South Africa. Here is some history of the Witwatersrand Gold Style Ore Deposits as they related to South Africa since the arrival of the Dutch and the southernmost tip of the continent in The Dutch set up a small fort where Cape Town stands today and started Market Gardens as a place that the Dutch East India Company ships to shelter and to restock with freshwater and provisions on the long journey.

AbstractNew major- and trace-element data are presented for low-grade metamorphosed marine shale units of the highly auriferous Mesoarchean Witwatersrand Supergroup in the Kaapvaal Craton, South Africa.

Comparison of the most altered with the least altered samples revealed that postdepositional modification of shale chemistry was significant only near contacts with over- and underlying coarser. Beginning with a shale parent, Barrovian metamorphism produces a sequence of metamorphic rocks that goes through slate, and then through phyllite, schist, and gneiss.

It can be hard to imagine at first that all these very different looking rocks can come from the same sedimentary parent, but. The results of this survey are shown on an excellent map (Geological Map of the Witwatersrand Gold Field, 3 sheets, ) on the scale of 1 toor almost an inch to the mile.

Read "Widespread fluid infiltration during metamorphism of the Witwatersrand goldfields: generation of chloritoid and pyrophyllite, Journal of Metamorphic Geology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.(Economic Geology Research Institute-Hugh Allsopp Laboratory, School of Geosciences, University of the Witwatersrand, monitor all the material being published in a wide spectrum of books, journals, conference proceedings, abstract volumes and field guides.

Aspects of volcanism and metamorphism of the Onverwacht Group.The low grade metamorphism of shale produces _____.

Selected Answer: Slate Answers: Marbl e Schis t Gneis s Slate Question 2 1 out of 1 points Which of the following changes may occur during metamorphism? Selected Answer: all of the above Answers: Certain minerals may recrystallize. The rock becomes more compact.

Crystals may grow larger. all of the above Question 3 0 out of 1 points A.