Here's why:
* Komatiites: These are ultramafic volcanic rocks, meaning they are extremely rich in magnesium and iron, with very low silica content. They are incredibly hot (around 1600°C) and have very low viscosity, allowing them to flow great distances.
* Ancient, Stable Areas: Komatiite eruptions occurred in the Archean Eon, a period from 4 billion to 2.5 billion years ago. During this time, the Earth was much hotter, and the mantle was more fluid. This allowed for the generation of magma with the necessary chemical composition to produce komatiites. Additionally, tectonic activity was very different, leading to the formation of large, stable continental areas.
Where to find them:
* Greenstone Belts: These are ancient, eroded volcanic and sedimentary rock sequences. Komatiites are commonly found within these belts.
* Southern Africa: The Barberton Greenstone Belt in South Africa is a prime example of an area rich in komatiites.
* Western Australia: The Pilbara Craton in Western Australia is another notable location with komatiite occurrences.
* Canada: The Abitibi Greenstone Belt in Canada also hosts a significant number of komatiite formations.
It's important to note:
* Komatiites are incredibly rare in modern times, as Earth's mantle has cooled significantly.
* Although they are iron-rich, they are not necessarily *iron ore*, which is a commercially viable source of iron. They are, however, a valuable source of information about the early Earth.
If you'd like to know more about specific locations or the geological processes that led to their formation, please let me know!
