Ancient Mega-Tsunami Slammed Into Madagascar, Scientists Say

According to a team of geologists, some 10,000 years ago a space object slammed into the Indian Ocean creating a mega-tsunami that enveloped the coast of Africa and Madagascar. The findings were shared at the winter meetings of the American Geophysical Union.

Researchers identified “chevrons,” or dune-like sediment deposits on Madagascar, that scientists think could be the imprints of an ancient mega-tsunami. The findings are supported by 22 samples from the dunes that show high levels of carbonate which date back to about 10,000 years ago.


Did a mega-tsunami or wind create the massive dunes on Madagascar? Image credit: Shuttershock

The carbonate samples, which come from marine micro fossils, is a key piece of evidence to support the mega-tsunami theory. Since the cliffs on Madagascar are 175 meters high, a wave would need to be about 90 meters high to leave such deposits.

Lead author of the study Dallas Abbott said: “While most researchers have assumed that the sand in the dunes was transported inland by the wind, we instead have proposed that the deposits are from a mega-tsunami event.”

This distinction by the team has lead to some criticism of their findings within the geological community.

Geologist Joanne Bourgeois at the University of Washington says her research doesn’t support the findings by Abbott and her team. In 2009, she modeled the likely path of a mega-tsunami and found that the alignment of chevrons on Madagascar were inconsistent with the model. Moreover, her research showed that the chevrons line up precisely with the dominant wind direction. She also highlights a lack of mega-tsunami evidence on Africa, which is so close it should have some imprints of the tsunami as well.

Abbott contends that if the fossils were blown in land to their final resting place, they would have been powder by the time they landed. Since they are not powder, and because they are found at the top of a 175 meter dune, Abbott still believes the mega-tsunami theory to be the most likely.

Love me some healthy science debate to ring in the new year.


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