December 12th, 2012 by Joshua S Hill
A new analysis of sediments from the island of Bonaire in the Caribbean makes a convincing case for a tsunami dating back 3,300 years, one that had a massive impact on the island’s ecosystem.
Scientists studied sediments that suggested the tsunami had entirely changed the coastal ecosystem and sedimentation patterns in the area.
The research, published by Dr. Max Engel and colleagues, from the University of Köln in Germany in the journal Naturwissenschaften – The Science of Nature, found the evidence in a coastal lagoon.
Documented history has only gone back 500 years, but the overwash deposits from the coastal lagoon provide evidence for this large tsunami 3,300 years ago.
Engel and his colleagues studied sediment cores from Washington-Slagbaai National Park and looked specifically at grain size distribution, carbonate content, organic matter, magnetic susceptibility and fauna.
Their conclusion was that these sediments had criteria normally linked with tsunami deposits.
The authors conclude: “This single catastrophic event is of long-term ecological significance. 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.”
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