Eldredge and Biek

Imagine a time long ago where the earth was once so cold that in its entirety it was covered by ice. In the earths 4.6 billion year history it is commonly believed that the earth has suffered to the dramatic effects of 5 ice ages (Eldredge and Biek). The causes of these disasters are not fully understood. However, across the scientific world, there was a consensus that no matter how ferocious the ice age was there would always be parts of the earth that were kept warm and safe. Eldredge and Biek describe an ice age as “ a long interval of time when global temperatures are relatively cold and large areas of the Earth are covered by continental ice sheets and alpine glaciers.” The effects of an ice age are clear; the freeze gradually spreads originating from the poles but never reaches the tropics. It has long been believed that the tropics can never freeze. Nevertheless, this basic belief cannot explain geologic findings in Namibia 600 million years ago and strong evidence for the snowball earth.

Namibia, in southern Africa, was the beginning of the journey in geological evidence for an extensive glaciation. It is a land of extreme heat with a landscape carved by wind and erosion with a location that has been in the tropics for millions of years. Conversely, the geological records show through glacial sediments that ice once had a part to play in the history of this country. Not only Namibia but across the world there have been 2 billion year old glacier sediments found. Trying to work out where they came from has been the biggest problem to date. Glacial sediments known as drop stones are “Fragments of rock that are isolated in sedimentary rock by dropping down through a column of water during the formation of sedimentary rock” (Advent of Complex Life, NASA). These drop stones have been located throughout Namibia and could only have been brought by one thing, a glacier.

The theory that a place like Namibia, which was thought to have been hot for millions of years, once was covered in ice was so radical that the majority of the scientific community deemed it as ridiculous. Brian Harland of the University of Cambridge led the theory in the 1940’s. He made several trips to the arctic where he was able to study drop stones and tillites in detail and the signs of glaciations. Upon return Harland examined rocks from across the globe in which he found some fascinating findings. In 1964 alongside Rudwick he published the article “The Great Infra-Cambrian Ice Age” which started the movement of the snowball theory. The article was the first publication of the idea of global glaciation. He wrote on the findings of glaciation from across the globe. He states in his document “In 1891 the Norwegian geologist Hans Henrik Reusch found an ancient deposit he interpreted as being a glacial moraine. The deposit, now believed to be a tillite, lay atop a striated rock surface beside Varanger Fjord in Norway. Both the tillite and the