A freeze core of sediment extracted from the bottom of Crawford Lake during research led by Brock University is now part of the Canadian Museum of Nature’s permanent collection.

The core was placed into the Museum’s National Biodiversity Cryobank of Canada in Gatineau, Que. during a ceremony on April 11. The Cryobank contains a biorepository of specimens from across Canada and abroad, stored at -180C, to be used in ongoing research.

The core came from multi-institutional research directed by Professor of Earth Sciences Francine McCarthy to study Crawford Lake’s geologic record for evidence of human activity. The team collected sediment layers from the bottom of Crawford Lake using a process called freeze coring.

Brock’s Acting Vice-President, Research Michelle McGinn told the gathering the team’s findings were exciting and important for understanding human-induced changes in the natural environment.

“Traces of pollution and other human-made materials captured in the frozen core collected by Dr. McCarthy and her team tell the history of our planet year by year,” she said. “This record documents alterations to the environment that align with human activity and shape how we understand geologic time. By preserving and curating this significant record, the Canadian Museum of Nature is supporting further research by other scientists.”

Roger Bull, Head of Operations for the National Biodiversity Cryobank at the Canadian Museum of Nature, lowers the freeze core sediment sample from the bottom of Crawford Lake into an ultra-cold freezer where it will be preserved and curated as a permanent marker of human impacts on the environment, accessible to researchers around the world.

In the evening, McGinn and members of the research team spoke about the research at a public event at the Canadian Museum of Nature’s Ottawa location.

In the lead-up to the event, McCarthy said the core transfer marked a notable step in the research process.

“The value of the annually layered sediments that accumulate undisturbed at the bottom of this unusual lake to the natural history of Canada and the world is underscored by our national Museum’s commitment to archive this core,” she said in an earlier interview.

Since the 1970s, Brock scientists have been studying the Milton, Ont., lake’s geology and history. McCarthy’s team was examining the Lake’s geology as part of international efforts to establish a new epoch, called the Anthropocene, in the Earth’s geologic timescale.

Part of the process involved finding a location on Earth — a reference point, called the GSSP for short — where the lower boundary of a next epoch could be seen clearly.

This was in response to a worldwide movement of geologists to determine the extent to which human activity has changed the Earth’s geology.

Ultimately, the Subcommission on Quaternary Stratigraphy within the International Union of Geological Sciences, following a disputed vote, decided against the creation of a new epoch, the Anthropocene, at this time.

Professor of Earth Sciences Martin Head is Second Vice-Chair of that Subcommission. He had encouraged McCarthy to set up a Crawford Lake research group that would examine Crawford Lake as being a possible GSSP for the proposed Anthropocene epoch.

“The Crawford Lake core continues to symbolize the Anthropocene with its exquisitely detailed record of human impacts,” Head said during the cryobank ceremony.

“In particular, its unsurpassed record of plutonium-239 will continue to serve as the primary identifier for the base of the Anthropocene,” he said. “The Anthropocene is now defined — even as it still awaits official designation.”