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+--- Thread: Research Was ‘Snowball Earth’ a global event? New study delivers best proof yet (/thread-16806.html)
Was ‘Snowball Earth’ a global event? New study delivers best proof yet - C C - Nov 12, 2024
https://www.eurekalert.org/news-releases/1064305
INTRO: Geologists have uncovered strong evidence from Colorado that massive glaciers covered Earth down to the equator hundreds of millions of years ago, transforming the planet into an icicle floating in space.
The study, led by the University of Colorado Boulder, is a coup for proponents of a long-standing theory known as Snowball Earth. It posits that from about 720 to 635 million years ago, and for reasons that are still unclear, a runaway chain of events radically altered the planet’s climate. Temperatures plummeted, and ice sheets that may have been several miles thick crept over every inch of Earth’s surface.
“This study presents the first physical evidence that Snowball Earth reached the heart of continents at the equator,” said Liam Courtney-Davies, lead author of the new study and a postdoctoral researcher in the Department of Geological Sciences at CU Boulder.
The team will publish its findings the week of Nov. 11 in the Proceedings of the National Academy of Sciences. Co-authors include Rebecca Flowers, professor of geological sciences at CU Boulder, and researchers from Colorado College, the University of California, Santa Barbara and University of California, Berkeley.
The study zeroes in on the Front Range of Colorado’s Rocky Mountains. Here, a series of rocks nicknamed the Tavakaiv, or “Tava,” sandstones hold clues to this frigid period in Earth’s past, Courtney-Davies said.
The researchers used a dating technique called laser ablation mass spectrometry, which zaps minerals with lasers to release some of the atoms inside. They showed that these rocks had been forced underground between about 690 to 660 million years ago—in all likelihood from the weight of huge glaciers pressing down above them.
Courtney-Davies added that the study will help scientists understand a critical phase in not just the planet’s geologic history but also the history of life on Earth. The first multicellular organisms may have emerged in oceans immediately after Snowball Earth thawed.
“You have the climate evolving, and you have life evolving with it. All of these things happened during Snowball Earth upheaval,” he said. “We have to better characterize this entire time period to understand how we and the planet evolved together.” (MORE - details, no ads)