Okay kiddo, have you ever played with rocks and noticed that they all look different? A long time ago, there was a big land called the Barberton Greenstone Belt where there were lots of different rocks. Some of these rocks are really old - like almost 3.5 billion years old!
Now, some of these old rocks are special because they have gold inside of them. Yup, just like how some rocks have crystals inside of them! People have been mining for gold in this area for a really long time.
But why is it called the "greenstone belt"? Well, greenstone is a type of rock that's green in color and it's really important because it tells us about the history of the Earth. Scientists have been studying the rocks in this area to learn more about how the Earth was formed.
So basically, the Barberton Greenstone Belt is an area with lots of really old rocks and some of them have gold in them. The rocks also help scientists learn about the history of the Earth. Cool, huh?