Evidence seen of ancient Caribbean tsunami

A tsunami 3,300 years ago caused long-term change on a Caribbean island, entirely altering its coastal ecosystem, German researchers say. Scientists at the University of Cologne, writing in the journal The Science of Nature, said a detailed analysis of sediments from the island of Bonaire presents convincing evidence for an extraordinary wave impact even though no historical records of tsunamis exist for this island. Although the island, in the southern chain of the Lesser Antilles, has not experienced a tsunami during the past 500 years -- the period of historical documentation -- overwash deposits from a coastal lagoon provide evidence for at least one such event in prehistory, the scientists said. "This single catastrophic event is of long-term ecological significance," they said. "Formation of a barrier of coral rubble was triggered by the tsunami separating a former inland bay from the open sea and turning it into a highly saline lagoon which persists until today. "Further studies of the geology of tsunamis, using well-dated deposits, are required over the entire Caribbean to reconstruct reliable patterns of magnitude, frequency and spatial occurrence of tsunami events and their environmental impact," the researchers wrote in the published study.