Radioactive Particles in Pacific Sediment Could Mark The Beginning of a New Epoch

The Anthropocene is the name some scientists are giving to the current geological epoch, marked by the point in time when human activity started having a significant impact on the geology.

Scientists believe they have determined the beginning of the Anthropocene through the discovery of radioactive material in the northwest Pacific Ocean.

The material comes from atomic tests that took place in the region in the 1950s.

The research team believes that the Anthropocene started in 1954.

When testing stopped, we had to find clear indications of the effects from the 1950s up to 1963.

We collected coral skeletons from the island of Ishigaki southwest of Okinawa. We can more accurately date the signatures we see in the soils by comparing them to corals.

The collection of these samples is difficult due to the fact that they can be dispersed over a wide area and easily moved by ocean currents. It was important to cross- reference the corals that are in place.

Corals have distinct rings that correspond to specific years of growth. They don't give a lot of information about the state of the water, but they are a good complement to the material from the past.

A variety of chemical analysis techniques were used to study the slices of the sample.

Three tons of plutonium were released into the sea and atmosphere but they dispersed far and wide. "So we're looking for very small signatures, so that's what we're trying to find."

Scientists believe that the major shifts we've seen in recent decades, mostly triggered by humans, need to be recognized, because the geological epoch that we're currently in is the Holocene.

The Anthropocene can't be decided when the industrial revolution should start or when the rise in carbon emissions should begin. There is a point at which the new study starts.

"This work is important not just to solidify the definition of the Anthropocene, but also because the successful use of our method means it could also be used to improve ocean and climate models, or even help explore past tsunamis and other geological Hazards."

The research was published in a scientific journal.