In Lille, France, the “Anthropocene Working Group” (AWG) of the International Commission on Stratigraphy (ICS) has now determined, after lengthy discussions, the location where human activity was most understandably reflected over time. Originally, twelve proposals for a globally valid main reference point (“Golden Spike”) were under discussion. Karlsplatz in Vienna was also in the running. However, this has already been eliminated in a previous round of voting among the experts, as geologist Michael Wagreich of the University of Vienna, who is involved in the AWG, explained in an interview with the APA.
Geologists divide Earth’s history into eras. We are currently living in the Holocene, which began nearly 12,000 years ago after the end of the last Ice Age. Traditionally, these geological ages are determined according to the characteristics of the rock layers, the method is called “stratigraphy”. For Wagreich, the decision taken at the International Congress of Stratigraphy currently taking place in northern France to choose Crawford Lake, near the city of Toronto, as the “Golden Spike” should not yet be equated with the “proclamation of the Anthropocene”. The procedure up to this point is quite complicated.
After the current proposal (“proposal”) of the working group, there are still new rounds of voting. The International Union of Geosciences then has the last word. The matter is by no means a “pathway”, because establishing the Anthropocene around 1950 is not easy and is a matter of heated debate in the scientific community, explained Wagreich.
Now, Crawford Lake has been able to overcome the necessary 60 percent voting hurdle, explained AWG member Colin Waters from the University of Leicester (Great Britain) during a press conference. The proposal is now in a process that should be completed by August 2024. Then the “Age of Man” would be on track.
The research at Crawford Lake was led by Francine McCarthy of Brock University (Canada). The site impresses with two conditions that are difficult to reconcile: the layers of water do not mix there and the bottom of the lake is more or less “isolated from the rest of the planet”, said McCarthy about the small lake of about 24 meters deep. At the same time, deposits form in the water every year, which, however, make it possible to draw conclusions about human influence.
This is because the bottom of the lake is made of limestone. When the water temperature rises in summer, calcite crystals are formed there, in exchange for compounds that naturally sink into the lake’s unmixed water column and contain information about conditions in the outside world, so to speak, explained the scientist. Each year has its own “white layer” for geologists to read. It is already possible to perceive the influence of indigenous groups in the region in the 13th and 15th centuries and the European colonization from the beginning of the 19th century.
The radionuclide plutonium-239 from above-ground nuclear testing during the “Cold War” can also be clearly demonstrated – namely, the global influence of humans on geology. You can also see the “Great Acceleration” that started around the year 1950, when man started to change the face of the planet more than ever before. McCarthy explained that all the criteria the working group had established for this test would be recognizable in the small lake “like dominoes” in annual stratifications after the year 1950.
For Wagreich, who has been investigating the “Anthropocene waves” underground in the capital for a long time, it was not to be expected that Vienna could become the “golden peak”. The proposal was based on samples collected at the construction site for the redesign of the Museum of Vienna on Karlsplatz together with the City’s Department of Archeology.
Among other things, plutonium 239 and 240 from atomic bomb tests between 1950 and 1964 could be detected in the city’s sediments. However, due to various building works, the annual layers do not remain intact on top of each other. “We have a good following there,” but that is more consistent elsewhere, Wagreich explained. However, Karlsplatz remains one of the landmarks for the Anthropocene.
(SERVICE – Anthropocene Working Group: http://quaternary.stratigraphy.org/working-groups/anthropocene; Lille Conference: https://strati2023.sciencesconf.org)