Between two-and-a-half and four billion years ago, during a time known as the Archaean Aeon, ash and debris from volcanic eruptions filled the Earth’s atmosphere and asteroids pummelled the oceanic planet. A dim-burning sun hung above the horizon and the Earth spun faster than it does today, causing shorter days. This is when Earth’s first continents were formed, creating shallow-water environments that allowed photosynthesis to take place.

The Makhonjwa Mountains that rise behind the town of Barberton in South Africa’s Mpumalanga Province date back 3.57 billion years and were one of the first landmasses to rise out of the ocean. Recently declared the country’s newest Unesco World Heritage Site, the mountains, also known as the Barberton Greenstone Belt, showcase some of the Earth’s oldest surface rocks. (Credit: Iga Motylska)

http://www.bbc.com/travel/story/20180920-the-south-african-mountains-older-than-continents