The shale found on Waterloo Farm was deposited about 360-million years ago, just a short time in geologic terms before the Devonian Period came to an end in one of the five great extinctions.
Gess said trees found on Waterloo Farm helped explain what might have caused the end Devonian extinction.
The first trees began to grow in the later part of the Devonian Period (from 385 to 360-million years ago).
Palaeontologists had evidence of trees in the tropical regions, but they were not sure about the spread of plant life into subtropical or polar regions.
Fossil plants found in the Waterloo deposits showed that at that time trees had spread right around the globe even to this estuary in the south of Gondwana which was in the Antarctic Circle at that time.
“When we found trees right outside Makhanda, we realised that trees had actually spread throughout the world,” Gess said.
“That actually influenced the development of the main theory about the end Devonian extinction.
“Which is that the spread of these first trees had the opposite effect of — what we’re looking at now, the greenhouse effect — it brought on an ice-house effect.”
Trees absorb a lot of carbon dioxide which causes a cooling effect on the global climate, and ever since then “we’ve lived in a forest mediated environment, but some of the evidence for that comes from this fossil site, here in Makhanda”.
Visitors to the festival should try to spend time at the Devonian Ecosystem Project — it is really worth the effort.
The exhibition is at an Albany Museum satellite building on Beaufort street, next to the Glennie Hall at Victoria Primary School.
To get a pin, put “Devonian Ecosystem Project” into Google Maps.
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