“The AWG decided the timing of the boundary before deciding on the marker, not the other way around,” says Ellis. Erle Ellis, a geographer at the University of Maryland, Baltimore County, and an AWG member, has criticized the committee’s plans for designating the start of the Anthropocene. But some scientists argue that human activity has been shaping the planet for thousands of years, and that the working group has settled too quickly on the 1950s for the start of the proposed epoch. Once they pick their representative marker, researchers working with the AWG need to gather enough evidence from around the world to convince the governing bodies of geoscience that they have found a truly reliable signal for the start of the Anthropocene. “There’s a big bomb spike somewhere between 19 that is quite distinct and unmistakable,” says Zalasiewicz. The committee’s current plan is to look to the legacy of the atomic age, when radioactive debris from mid-twentieth-century nuclear bomb blasts left a fingerprint of radioisotopes in the atmosphere, rocks, trees and even humans. Researchers collect a sediment core from Crawford Lake to study possible markers of the Anthropocene. “Scientifically, in terms of evidence, we’re spoiled for choice, but we have to pin it down,” says Jan Zalasiewicz, a palaeobiologist at the University of Leicester, UK, and chair of the AWG. Given how much people have done to the planet, there are many potential markers. To define a new epoch, the researchers need to find a representative marker in the rock record that identifies the point at which human activity exploded to such a massive scale that it left an indelible signature on the globe. This new epoch would mark a clear departure from the Holocene, which started with the close of the last ice age. The Anthropocene Working Group (AWG), a committee of 34 researchers formed by the International Commission on Stratigraphy (ICS) in 2009, is leading the work, with the aim of crafting a proposal to formally recognize the Anthropocene. Now, scientists are looking for much more recent, and significant, signs of upheaval tied to humans.Ĭore samples taken from the lake bottom “should translate into a razor-sharp signal”, says Francine McCarthy, a micropalaeontologist at nearby Brock University in St Catherines, Ontario, “and not one blurred by clams mushing it about.” McCarthy has been studying the lake since the 1980s, but she is looking at it now from a radical new perspective.Ĭrawford Lake is one of ten sites around the globe that researchers are studying as potential markers for the start of the Anthropocene, an as-yet-unofficial designation that is being considered for inclusion in the geological time scale. In high fidelity, it has captured evidence of the Iroquois people, who cultivated maize (corn) along the lake’s banks at least 750 years ago, and then of the European settlers, who began farming and chopping down trees more than five centuries later.
#LIVING EARTH CRAWFORD ARCHIVE#
Layers of sediment accumulate like tree rings, creating an archive reaching back nearly 1,000 years. This lake is unusually deep for its size so its waters never fully mix, which leaves its bottom undisturbed by burrowing worms or currents.
The mud layers in this lake could be ground zero for the Anthropocene - a potential new epoch of geological time. They are in search of a distinctive marker buried deep in the mud - a signal designating the moment when humans achieved such power that they started irreversibly transforming the planet. But beneath its surface, this pond in southern Ontario in Canada hides something special that is attracting attention from scientists around the globe. Credit: Modified from Corbis via GettyĬrawford Lake is so small it takes just 10 minutes to stroll all the way around its shore. The first explosion of a nuclear bomb in 1945 and later blasts spread radionuclides around the globe.
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