Jakarta –
Scientists identified geological sites that they think best reflect the beginning of the Anthropocene epoch, an epoch that marked a major step toward changing the official timeline of Earth’s history.
The Anthropocene or Anthropocene is the period that began when human activities began to have a global influence on the Earth’s ecosystem. This term appears to have been used by Soviet scientists since the early 1960s to refer to the Quaternary, the most recent geological period.
The term Anthropocene was first proposed in 2000 to reflect how profound human activity has changed the world.
“When 8 billion people have an impact on the planet, there is bound to be an impact,” said Colin Waters, honorary professor at the School of Geography, Geology and the Environment at the University of Leicester and chair of the Anthropocene Working Group (AWG), as quoted by CNN.
“At this time, the Earth is entering a new condition and this will be determined by a new geological epoch,” added Waters.
The AWG, a group currently consisting of 35 geologists, has been working since 2009 to make the Anthropocene part of Earth’s official timeline.
The group determined in 2016 that the Anthropocene epoch began around 1950, the beginning of the era of nuclear weapons testing, whose geochemical traces can be found throughout the world.
Since then, the researchers have considered 12 locations that could provide the critical evidence needed to support their proposal, nine of which have already been put to a vote.
Later, a team of scientists announced that Crawford Lake in Ontario, Canada best represents the geological impacts of the Anthropocene according to their research.
However, not everyone agrees that the Anthropocene is a geological reality, or that researchers have enough evidence to officially declare it a new epoch.
Earth Period
The geologic time scale provides a formal framework for our understanding of Earth’s 4.5 billion year history. Geologists divide the history of our planet into millennia, eras, periods and epochs.
For example, we currently live in the Meghalayan Age. It is part of the Holocene Epoch, which began at the end of the last ice age 11,700 years ago, when ice sheets and glaciers began to retreat.
The Holocene is part of the Quaternary Period, the latest division of the Cenozoic Era, which is part of the Phanerozoic Eon that lasted from 539 million years ago to the present.
These geology chapters are often named after the place where they were first studied. The Jurassic Period takes its name from the fossil-rich rocks of the French Jura Mountains, while the Cambrian Period gets its nickname from the Roman name for Wales.
Andrew Knoll, Fisher Professor of Natural History at Harvard University, says this scale is very helpful in his work as a paleontologist.
“When I say ‘Cambrian,’ it not only indicates the time between 539 and 485 million years ago, but a wealth of information about biota, environment, tectonics, paleogeography and much more. (It’s) like the Middle Ages, or the Renaissance,” he said Knoll.
If approved, the Anthropocene would be the third epoch of the Quaternary Period. This also means that the Holocene Epoch is very short compared to other epochs which lasted several million years.
Each division in the official timeline is also represented by a single geological site known as the Global Boundary Stratotype Section and Point (GSSP). Sites are considered places that best capture what is new or unique about a particular chapter in Earth’s history.
Each point is usually marked with a ‘golden spike’, driven into a particularly important layer of rock, although the location may be a stalagmite or ice core.
Cradle of the Anthropocene
For the Anthropocene, the proposed gold spike location is sediment released from the bottom of Crawford Lake that reveals geochemical traces of nuclear bomb testing, specifically plutonium, a radioactive element widely detected worldwide in coral reefs, ice cores, and peat bogs.
Crawford Lake was deemed the most suitable among eight other candidate locations selected through three rounds of scientific voting. Other potential locations include a peat bog in Poland’s Sudeten Mountains, Searsville Lake in California, a stretch of seafloor in the Baltic Sea, a bay in Japan, a water-filled volcanic crater in China, an ice core drilled from the Antarctic Peninsula, and two coral reefs in Australia and another in the Gulf of Mexico.
Waters said it was difficult to choose between the different locations and the voting results were nearly identical, but he believes Crawford Lake won because the proposed starting point for Anthropocene geochemistry related to sediment was so precise.
This lake covers 2.4 hectares, but is very deep, namely almost 24 meters. Sediments found at the bottom can be divided into annual layers to serve as markers for human geochemical activity.
“This analysis allows scientists to see changes in annual resolution,” explains Francine McCarthy, a professor of Earth sciences at the University of Brock in Canada who has studied the lake.
“The shape (of the lake) limits the mixing of the water column so that the bottom waters do not mix with surface water. The bottom of the lake is completely isolated from the rest of the planet except for the part that sinks to the bottom,” he explained.
However, the selection of Crawford Lake is not the final word on whether the Anthropocene is recognized as an official unit of geologic time. AWG will submit a proposal to make the Anthropocene official to the Subcommission on Quaternary Stratigraphy.
If the subcommission members agree with a 60% majority vote, the proposal will then be forwarded to the International Commission on Stratigraphy, which must also vote and approve with a 60% majority vote for the proposal to be ratified.
Both bodies are part of the International Union of Geological Sciences which represents more than 1 million geoscientists worldwide. A final decision is expected to be taken at the 37th International Geological Congress in Busan, South Korea, in August 2024.
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2024-01-15 11:15:02
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