Earth experienced a period of massive and rapid melting after the last ice age, new research suggests

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At the end of the last global ice age, the frigid Earth reached a pre-built limit of climate change and melted into a slimy planet. The results of the Virginia Tech-led study show direct evidence of a slushy planet (also known as the “Plume World Ocean” era), when sky-high carbon dioxide concentrations sent the frozen Earth into a period of massive and rapid thawing. provided geochemical evidence for the first time.
“Our results have important implications for understanding how Earth’s climate and ocean chemistry changed after the extreme conditions of Earth’s last ice age,” said lead author and former Virginia Tech professor said Tian Gan, a university postdoctoral researcher. Gan collaborated with geologist Shuhai Xiao on the study, which was published Nov. 5 in the Proceedings of the National Academy of Sciences.
frigid earth
The last global ice age occurred about 635 to 650 million years ago, when scientists believe global temperatures dropped and polar ice sheets began creeping around the hemisphere. The growing ice reflected more sunlight from the Earth, causing a spiral of plummeting temperatures.
“A quarter of the ocean has frozen because carbon dioxide levels are so low,” said Hsiao, who was recently inducted into the National Academy of Sciences.
Once the surface ocean was sealed off, the chain of reactions stopped.
Water circulation has stopped. There is no evaporation and almost no rain or snow falls. Without water, the carbon-consuming process called chemical weathering, in which rocks erode and disintegrate, was significantly slowed. Without weathering or erosion, carbon dioxide began to accumulate in the atmosphere, trapping heat.
“It was only a matter of time before carbon dioxide levels were high enough to break the ice pattern,” Hsiao said. “When it ended, it probably ended catastrophically.”
plume world
Suddenly, my fever started to rise. The ice caps began to retreat, and the Earth’s climate rapidly retreated into a wet, succulent climate. In just 10 million years, Earth’s average temperature has varied from -50 to 120 degrees Fahrenheit (-45 to 48 degrees Celsius).
However, the ice did not melt and simultaneously remix with seawater. The research results paint a very different picture of the world than we imagine. Vast rivers of glacial water flow from the land into the sea like a reverse tsunami, pooling on top of salty, highly concentrated seawater.
Researchers tested this version of the prehistoric world by observing a series of carbonate rocks that formed as the global ice age was ending.
They analyzed a specific geochemical signature recorded within the carbonate rocks: the relative abundance of lithium isotopes. Plume World’s ocean theory suggests that the geochemical signature of fresh water is stronger in rocks formed under snowmelt water near the coast than in rocks formed under deep salt ocean waters offshore. That’s it. And that’s exactly what the researchers observed.
Xiao said the discovery not only brings more focus to the limits of environmental change, but also pushes researchers to the forefront of biology and the resilience of life under extreme conditions such as heat, cold and mud. said to give further insight.
Further information: Tian Gan et al, Evidence for lithium isotopes in Plume World oceans in the aftermath of a Marinoan snowball Earth, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2407419121
Provided by Virginia Tech
Citation: After the last global ice age, the Earth experienced a period of extensive and rapid melting, new research suggests (November 5, 2024) https://phys.org/news/2024 Retrieved November 5, 2024 from -11-earth-underwent-massive-rapidperiod.html
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