The
Bushveld Igneous Complex (or
BIC) is a large
layered igneous intrusion within the Earth's
crust which has been tilted and
eroded and now
outcrops around what appears to be the edge of a great
geological basin, the
Transvaal Basin. Located in
South Africa, the BIC contains some of the richest
ore deposits on Earth. The reserves of
platinum group metals (PGMs),
platinum,
palladium,
osmium,
iridium,
rhodium, and
ruthenium are the world's largest, and there are vast quantities of
iron,
tin,
chromium,
titanium and
vanadium.
Gabbro or
norite is also
quarried from parts of the Complex and rendered into
dimension stone. The site was discovered around 1897 by
Gustaaf Molengraaff.
Origin
The Bushveld Igneous Complex covers a pear-shaped area in the central
Transvaal is divided into an eastern and western lobe, with a further northern extension. All three sections of the system were formed around the same time — about 2 billion years ago — and are remarkably similar. Vast quantities of molten rock from the Earth's
mantle were brought to surface through long vertical cracks in the Earth's crust — huge arcuate differentiated
lopolithic intrusions — creating the geological intrusion known as the Bushveld Igneous Complex. These intrusions are thought to predate the nearby
Vredefort impact to the south, by some 30 million years. The...
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