The Anthropocene Working Group has chosen Crawford Lake as a "golden spike" that can help scientists understand this new geological epoch

Crawford Lake, near the Canada-US border, has been chosen as a site that will help scientists understand when our current geological epoch, the Holocene, is replaced by a new epoch, the Anthropocene. Spoiler alert: Many scientists believe we've been in the Anthropocene for years, decades, and even centuries. What's the Anthropocene? The term describes a geological epoch characterized by human-created changes to our planet. Natural History Museum UK explains:

We are living in a time many people refer to as the Anthropocene. Humans have become the single most influential species on the planet, causing significant global warming and other changes to land, environment, water, organisms and the atmosphere.

The word Anthropocene comes from the Greek terms for human ('anthropo') and new ('cene'), but its definition is controversial. It was coined in the 1980s, then popularised in 2000 by atmospheric chemist Paul J. Crutzen and diatom researcher Eugene F. Stoermer. The duo suggested that we are living in a new geological epoch.

Recently, the Anthropocene Working Group decided that Crawford Lake is the perfect spot to track the Anthropocene—it's what the group calls a "golden spike." ABC News (Australia) explains:

The vote is the culmination of a three-year project to find the most suitable site, Colin Waters, chair of the working group, said.

It's also one step closer to confirming that Earth has entered a new epoch — one triggered by burning fossil fuels, nuclear bomb tests and other human activity . . . 

The idea that humans have forced changes to the planet so substantive that we've shifted into a new epoch was first popularised by the late Dutch chemist and Nobel Laureate Paul Crutzen in 2000 . . . 

Professor Crutzen suggested the Anthropocene began with the Industrial Revolution.

But, Dr. Waters said, while natural climate archives such as sediments deposited in some lakes do show hints of the industrialisation of the time, those signs are not consistently seen around the globe . . . 

This is why the Anthropocene Working Group, which formed in 2009, decided the new epoch would be defined as starting in the mid-20th century.

Post-World War II, mining, fossil fuel burning, trade and pollution ramped up — a time US historian John McNeill called the "Great Acceleration" — and this left its mark in the geological record around the world.

The working group needed a site on Earth that clearly showed traces of the Great Acceleration and could provide a primary marker for the new geological epoch. 

Such sites are also known as "golden spikes", after the physical objects sometimes driven into the rock at those locations.

The group came up with a dozen potential golden spike sites, including one on Flinders Reef in Australia. And after three rounds of voting, the Anthropocene Working Group finally decided on Canada's Crawford Lake as its preferred next golden spike.

Given the unique nature of Crawford Lake—air particles throughout the years, such as ash from coal combustion and pollen, have settled onto the bottom of the lake, where minerals in the lake water have preserved a detailed record over time—scientists will be able to see human activity, down to individual years. Again, ABC News:

When Professor McCarthy's team at Brock University and independent teams at other laboratories analysed the sediments, they saw distinct spikes in plutonium and carbon isotopes in layers that formed in the early 1950s — telltale signs of nuclear testing fallout.

They also saw increases in the amount of fly ash, as well as a sharp decline in elm pollen, coinciding with the arrival of the deadly Dutch elm disease in the region in the late 1940s.

Even the calcite layers were affected. Acid rain that fell in the area during the Great Acceleration prevented as much calcite from forming, so the white layers around 1950 are relatively thin.

To read more about how Crawford Lake will help scientists better understand the Anthropocene, read the rest of the ABC News story here.