Huronian glaciation facts for kids
The Huronian glaciation (or Makganyene glaciation) lasted from 2.4 billion years ago (Gya) to 2.1 Gya, during the Palaeoproterozoic era. It was named after evidence was collected from Lake Huron region in North America. There, three separate horizons of glacial deposits are separated by non-glacial sediment.
It was one of the most severe and longest ice ages in geologic history, similar to the Snowball Earth ice ages that happened in the Neoproterozoic era.
The glaciations were probably triggered by the Great Oxygenation Event (GOE), which removed atmospheric methane (a greenhouse gas), and eventually supplied free oxygen to the atmosphere. The alternate warm and ice age periods was probably caused by a repeating cycle. Cyanobacteria flourished in the warm periods, producing huge amounts of oxygen. The oxygen removed the free methane, and used up carbon dioxide. This caused the temperature to crash. This slowed down the bacteria. So the temperature rose again.
However, it is also possible that there was a 250 million year lull in volcanic activity, resulting in lower carbon dioxide levels and so reduced greenhouse effect.