DescriptionNebograniet, nabyskoot in Soutpankraterwand, a.jpg
Afrikaans: Nabyskoot van Nebograniet in die Soutpankraterwand, Gauteng, Suid-Afrika, waaraan 'n ouderdom van knap oor 2 miljard jaar toegeken word.[1] Nebograniet bestaan uit kwarts, kaliumveldspaat en ondergeskikte horingblende of biotiet. Die granietdikte is 3 000 m en is oorwegend in lae gevorm, met 'n ooreenstemmende spektrum van eienskappe. Van onder na bo verander dit van 1. 'n baie grofkorrelrige, grys graniet na minder grofkorrelrige grys en rooi graniet, met lokaal 'n rooi granofiriese graniet, 2. afname in die hoeveelheid donkerminerale, 3. vervanging van horingblende deur biotiet as die mees prominente donkermineraal, 4. 'n afname in Ba, Sr en Eu, en 'n toename in Rb.[2]
English: Cose-up view of Nebo granite in the Tswaing crater wall, Gauteng, South Africa, to which an age of just over 2 billion years is assigned. Nebogranite consists of quartz, potassium feldspar and subordinate hornblende or biotite. The granite thickness is 3,000 m and is predominantly formed in layers, with a corresponding spectrum of properties. From bottom to top it changes from 1. a very coarse-grained, gray granite to less coarse-grained gray and red granite, with locally a red granophyric granite, 2. decrease in the amount of dark minerals, 3. replacement of hornblende by biotite as the most prominent dark mineral, 4. a decrease of Ba, Sr and Eu and an increase of Rb.
↑Visser, D.J.L. (1989) Die Geologie van die Republieke van Suid-Afrika, Transkei, Bophuthatswana, Venda, Ciskei en die Koninkryke van Lesotho en Swaziland, Republiek van Suid-Afrika: Geologiese Opname: Departement van Mineraal- en Energiesake, p. 88 ISBN: 0-621-12516-4.
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