Reconstruction of the possible environment when the Barnt Green Volcanics was forming, around 484 million years ago, in a hot atmosphere charged with volcanic ash and lit by low angle sunlight. Lightning cracks through air rich in carbon dioxide levels at around 4400 parts per million, with oxygen at 19%.

The Barnt Green Volcanics consists in the main of tuff – cemented together volcanic ash – which fell into sea water. The ash blasted from explosive volcanoes associated with the subduction of the Iapetus oceanic plate beneath Avalonia.


Life in the Ordovician seas at the time of the Barnt Green Volcanics.