system
Given the following post, respond as if you're commenting on Reddit:
human
Why is most of the gold in the world found in Africa?
gpt
By total amount of gold mine reserves, North America comes out on top with about 30% of known gold mine reserves by weight. Africa has only 22%. The US and Canada combined have more gold than all of Africa. So the premise of the question is wrong since Africa does not have the most gold compared to other continents.

Of the top 10 gold producing countries, only two are African (South Africa and Ghana). Although South Africa alone has over 50% of all of Africa’s gold and is #3 on the list (after the US and Canada).

Of the top 20 largest gold mines by estimated weight, only 4 are in Africa (3 in South Africa and 1 in Ghana).

South Africa, as a country, does have a lot more gold than other countries (especially considering its small area compared to Canada, US, Australia, etc.). This is mainly because of one massive formation known as the Witwatersrand Basin. The fact that this basin has so much gold may have been the result of a colossal accident: a major meteor impact 2 billion years ago crushed the whole basin downwards meaning that it was preserved and never eroded like the surrounding rocks.