Posted on 11/19/2024 10:43:36 AM PST by Red Badger
New findings from Colorado’s rock formations provide physical evidence supporting the Snowball Earth theory, which suggests Earth was once frozen entirely, down to the equator. This study offers insights into a key phase of climate and life evolution. Credit: SciTechDaily.com Evidence from Colorado suggests glaciers once covered Earth to the equator, supporting the Snowball Earth theory. This discovery provides insight into early climate shifts and the evolution of life. Geologists have discovered compelling evidence in Colorado that hundreds of millions of years ago, enormous glaciers blanketed Earth as far as the equator, turning the planet into an icicle drifting through 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.
Tava Sandstone
Dark brown bands of Tava sandstone cut through other rocks. Credit: Liam Courtney-Davies
The team published its findings on November 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.”
Searching for snow
The term “Snowball Earth” dates back to a paper published in 1992 by American geologist Joseph Kirschvink.
Despite decades of research, however, scientists are yet to agree whether the entire globe actually froze. Geologists, for example, have discovered the fingerprints of thick ice from this time period along ancient coastal areas, but not within the interior of continents close to the equator.
Which is where Colorado enters the picture. At the time, the region didn’t sit at the northern latitudes where it does today. Instead, Colorado rested over the equator as a landlocked part of the ancient supercontinent Laurentia.
If glaciers formed here, scientists believe, then they could have formed anywhere.
Going deep
The search for that missing piece of the puzzle brought Courtney-Davies and his colleagues to the Tava sandstones. Today, these features poke up from the ground in a few locations along Colorado’s Front Range, most notably around Pikes Peak. To the untrained eye, they might seem like ordinary-looking yellow-brown rocks running in vertical bands less than an inch to many feet wide.
But for geologists, these features have an unusual history. They likely began as sands at the surface of Colorado at some point in the past. But then forces pushed them underground—like claws digging into the Earth’s crust.
“These are classic geological features called injectites that often form below some ice sheets, including in modern-day Antarctica,” Courtney-Davies said.
He wanted to find out if the Tava sandstones were also connected to ice sheets. To do that, the researchers calculated the ages of mineral veins that sliced through those features. They collected tiny samples of the minerals, which are rich in iron oxide (essentially, rust), then hit them with a laser. In the process, the minerals released small quantities of the radioactive element uranium. Because uranium atoms decay into lead at a constant rate, the team could use them as a sort of timekeeper for the planet’s rocks.
It was a Eureka moment: The group’s findings suggest that the Tava sandstone had been pushed underground at the time of Snowball Earth. The group suspects that, at the time, thick ice sheets formed over Colorado, exposing the sands to intense pressures. Eventually, and with nowhere else to go, they pushed down into the bedrock below.
“We’re excited that we had the opportunity to unravel the story of the only Snowball Earth deposits that have so far been identified in Colorado,” Flowers said.
The researchers aren’t done yet: If such features formed in Colorado during Snowball Earth, they probably formed in other spots around North America, too, Courtney-Davies said: “We want to get the word out so that others try and find these features and help us build a more complete picture of Snowball Earth.”
Reference:
“Hematite U-Pb dating of Snowball Earth meltwater events”
by
Liam Courtney-Davies, Rebecca M. Flowers, Christine S. Siddoway, Adrian Tasistro-Hart and Francis A. Macdonald, 11 November 2024, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2410759121
“undocumented glaciers”
A GREAT creation!
We bought a house in North Idaho about seven years ago and we were buried under a mile of the Cordilleran ice sheet.
Moral of my story: If you don't want to get buried under a mile of ice, don't buy a house near me.
I was just looking at Idaho State University's page on the Palouse and glacial Lake Missoula and learned a few new things:
In the Pleistocene ice age, vast ice caps covered much of North America and Eurasia; As much as a third of Earth's land surface was periodically covered in ice during this time. Four major glacial periods are recognized in North America: the Nebraskan, Kansan, Illinoisan, and Wisconsinan glaciations. Minor fluctuations occurred within each period.
Interglacial periods were periodically warmer than the present climate. Major interglacial periods include the Aftonian, Yarmouth, and Sangamon periods. The formation of glacial Lake Missoula occurred during the Pinedale (Wisconsinan) Glaciation.
bttt
Thank God For Global Warming!
“Thank God For Global Warming!”
No kidding! The earth’s normal is to be frozen. We have experienced (and are living in) brief “interglacial” periods with warmer than normal temperatures.
All I can say is, what a pant load.
Yes, I was taught this in school also. This study may have found real evidence of it in Colorado. Solid evidence of the snowball-earth theory has been missing before this, I think.
Yes, but you become a walking human battery due to all of the static electricity!
Heartless conservatives and their gas guzzling SUV’s destroyed these tropic glaciers.
HOW DARE YOU
The rest of the keywords (Joe Kirschvink, Snowball Earth), sorted:
Thanks Red Badger, nice twofer.
“Yes, but you become a walking human battery due to all of the static electricity!”
Really? lol
Please tell me more! lol
The True Polar Wander keyword, sorted (some duplicates in the earlier list):
“The end of the ice age occurred only 330 generations ago!”
I recall educating a couple nitwits here many years ago that fell into global warming quicksand without any facts, I was using the expression ‘only 100 great grandmothers ago.’ :^)
Love the Great Lakes and how young they are, can’t imagine living anywhere else on the planet.
“ Is that said in any statistics class any more?”
It PROBABLY still is being said but less of a probability.
Having lived and worked in a few VERY cold places during the winter, the humidity is very, very low. Therefore, static electricity builds up, and you practically need a ground strap to keep from shocking yourself or someone else. You can practically create your own light show just by taking off your tee shirt with no lights on. Ha!
Where did the water to make the ice come from, and once it melted, where did the water go? There's not enough water on earth to make that much ice. Glaciers never form uniformly, either. The coldest areas would have thicker glaciers than the warmest areas. These 'scientists' didn't give much forethought to the article.
I am strangely comfortable with that.
/Conor McMannus
Thank you for sharing that. I have lived in the desert all my life and it is dry, but never extreme dry cold so I did not know that. Crazy stuff!
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