What geological evidence was provided by the discovery of tillite in South Africa?

The discovery of tillite in South Africa provides significant geological evidence that an ice sheet covered southern Africa approximately 300 million years ago. Tillite is a type of sedimentary rock that forms from the glacial till, or the materials deposited by moving ice, such as glaciers. The presence of tillite suggests that there were glacial conditions in the past where ice sheets were extensive enough to leave behind such deposits.

This is an important piece of evidence supporting the theory of past climatic conditions in the geological history of the Earth. Specifically, it helps to illustrate the concept of past ice ages and contributes to our understanding of how the continents have shifted over time, particularly in relation to climate change during the Paleozoic Era. The tillite's formation in a region that is now characterized by a much warmer climate points to significant climatic transformations that have occurred over millions of years.