Comment »Posted on Monday 4 May 2009 at 3:50 pm by Jacob Aron
In Climate Change & Environment

Scientists have discovered evidence of a tsunami in New York City. If it happened today, Wall Street would be completely flooded. Thankfully for the bankers, the giant wave is thought to have hit around 2,300 years ago.

Evidence in sedimentary deposit samples taken from over 20 spots in New York and New Jersey suggest that the North East coastal region of the US saw massive upheaval in 300 BC. It could just have been a large storm, but researchers now believe the culprit to be a tsunami – a rare occurrence for the Atlantic Ocean.

Steven Goodbred, an Earth scientist at Vanderbilt University, examined sediment cores from the region and found large gravel, marine animal fossils and other strange deposits. He said that such a formation would only be formed fast waves and strong currents that a storm could not produced. “If we’re wrong, it was one heck of a storm,” he said.

Scientists are still debating the cause of such a tsunami, and such information is important in case a similar event could occur today. Some believe that an submarine landslide could have generated the massive wave. These undersea earthquakes are common in the Pacific and Indian Oceans, because continental plates collide at these locations. The Atlantic however is more stable, meaning that Atlantic tsunamis are rare and understudied.

Dr Goodbred plans to rectify this by collecting more cores from around the New York region, but he’s got competition. Another group, led by Columbia University geologist Dallas Abbott, believes that an asteroid impacting from space could be the answer.

Evidence found in New Jersey and the Hudson River contain carbon spherules, shocked minerals, and nanodiamonds – all materials common to asteroid impacts. Dr Abbott suggests that an asteroid hitting the water off the cost of New York would either generate the tsunami directly, or trigger Dr Goodbred’s submarine landslide. Dr Goodbreed and others are sceptical, thinking that the asteroid is an unnecessary complication. “The tsunami story stands on its own without the impact,” he said.

Figuring out just what caused the 2,300 year old tsunami is a pretty tall order. Radiocarbon dating can place the date of the debris to the nearest century, but the common nature of the material – wood, sand, shells and rock – make identification tricky. Whether the origins of the New York tsunami are in outer space or underwater, I’m just glad it happened a couple of millennia ago!


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