What is Vaalbara?
Q: What is Vaalbara?
A: Vaalbara is the name of Earth's first supercontinent, which formed in the Archaean era about 3,600 million years ago.
Q: Where does the name Vaalbara come from?
A: The name Vaalbara comes from the South African Kaapvaal craton and the West Australian Pilbara craton, which were combined to form the supercontinent.
Q: How old are Kaapvaal and Pilbara cratons?
A: Kaapvaal and Pilbara cratons are two of the best-preserved Archaean cratons on Earth, with remarkably similar early Precambrian rocks that have been dated between 3,500 to 2,700 mya.
Q: How often does a cycle of supercontinent formation occur?
A: The cycle of supercontinent formation, breakup, dispersal and reformation by plate tectonics occurs every 450 million years or so.
Q: What evidence suggests that Kaapvaal and Pilbara were part of a single supercontinent?
A: Palaeomagnetic data from rocks in both cratons showed that at 3,870 mya they could have been part of the same supercontinent. Both also show extensional faults which were active around the same time during volcanism as well as when impact layers were formed.
Q: Are there other areas where similar greenstone belts can be found?
A: Yes - similar greenstone belts can be found at the edges of Canada's Superior craton as well as across other former Gondwana and Laurasia continents.
Q: When did Vaalbara start to form?
A:Vaalbara started to form about 3,600 million years ago (mya) and was fully formed by 3100 mya before breaking up by 2500 mya.
