FIAMME IN BOULDER AT TRAFALGAR FALLS
The Roseau ignimbrite represents pyroclastic deposits
that were emplaced nearly 30,000 years ago in a violent eruption. At Trafalgar
Falls we were able to see the welded nature of the unit in the flattened
lense-shaped pumice fragments fiamme. These are evidence that a large thickness
of material was deposited hot, such that the pumice fragments were plastically
deformed. In this area the ignimbrite is over a hundred meters thick, whereas
approximately 10 km away, closer to the coast it is only a few meters thick.