Crawford Lake, nestled in Ontario, Canada, is proposed as a prime location to showcase humankind’s impact on Earth. Researchers are working to establish an updated geological period, termed the Anthropocene Epoch, to acknowledge changes caused by human activities.

Crawford Lake, with its unique sediment composition, is considered an ideal model example of this epoch.

The sediments contain indications of fossil fuel burning, including fallout. This evidence links increased greenhouse gas emissions and climate change that characterise the Anthropocene.

Crawford Lake’s sediments also contain plutonium, a byproduct of nuclear bomb tests.

Scientists aim to designate Crawford Lake’s sediments as a Global Boundary Stratotype Section and Point (GSSP). GSSPs serve as internationally recognised markers of significant geological events or boundaries.

Traditionally, GSSPs are represented by a physical marker; often, a brass nail hammered into a cliff face that holds substantial scientific value. However, researchers propose a different approach to Crawford Lake. They plan to place a brass plaque next to a frozen section of the lake’s sediments. This frozen section, preserved to maintain its integrity, will serve as a tangible testament to the Anthropocene Epoch’s inception.

To house this artefact and plaque, a museum will be established in the Canadian capital, Ottawa.

The bottom mud of Crawford Lake harbours annual layers that resemble a large dirty lollipop, as described by researchers. These layers, formed over time, hold vital clues to environmental changes. Each layer represents a year and acts as a historical archive of the lake’s evolution.

Within these annual sediment layers, scientists have identified various indicators of environmental change, including fossil fuel combustion products and plutonium. These elements offer direct evidence of the extensive use of fossil fuels and the consequential fallout of nuclear bomb tests.

Moreover, Crawford Lake sediments capture geochemistry and micro-ecology changes. The analysis enables a deeper understanding of how human actions have altered ecosystem balance and the long-lasting consequences of such changes.

The Anthropocene Working Group (AWG), a team dedicated to studying and defining the Anthropocene Epoch, emphasised the importance of charting and documenting environmental change.

Crawford Lake: Redefining Earth’s geological history

Scientists and educators commonly encounter the Chronostratigraphic Chart, a well-known visual representation of Earth’s history, in textbooks and classrooms. This chart divides Earth’s history into distinct blocks of time, such as the Triassic, Jurassic, and Cretaceous periods. It serves as a tool for scientists and educators to communicate the progression of Earth’s geological eras.

Currently, the epoch we live in is called the Holocene Epoch. This Epoch began approximately 11,700 years ago, marking the end of the last ice age. The proposal for the Anthropocene Epoch recognises that human activities have created a distinct geological period separate from the Holocene.

With its sediment composition and the proposed GSSP designation, the Crawford Lake effort will contribute to the scientific community’s goal of formally establishing the Anthropocene Epoch. It will provide a visual representation on the Chronostratigraphic Chart, acknowledging humanity’s impact on Earth.

The AWG is now convinced that a case has been made to update the Chronostratigraphic Chart and recognise the Anthropocene Epoch.

The AWG further suggests the 1950s as the formal start date for the Anthropocene Epoch. This period marks the onset of “Great Acceleration”, characterised by a rapid increase in human population and consumption patterns worldwide.

The “Great Acceleration” witnessed during the 1950s and subsequent decades was accompanied by a proliferation of “techno materials.” Materials such as aluminium, concrete, and plastic experienced widespread production and utilisation, leaving an enduring impact on the planet’s ecosystems.