'Golden spike' showing the moment Earth turned into a giant snowball discovered in ancient Scottish rocks (2024)

FAQs

What is the snowball Earth theory? ›

Snowball Earth hypothesis, in geology and climatology, an explanation first proposed by American geobiologist J.L. Kirschvink suggesting that Earth's oceans and land surfaces were covered by ice from the poles to the Equator during at least two extreme cooling events between 2.4 billion and 580 million years ago.

The Snowball Earth glaciations are recorded by tillite deposits. Another rock name frequently used in describing poorly sorted sedimentary deposits is diamictite. Diamictites are poorly sorted, but the name is purely descriptive, and doesn't necessarily imply a glacial origin for the deposit.

"It is conceivable that these 'Snowball Earth' events could have driven major extinctions, but apparently life, including complex eukaryotic organisms, managed to survive, attesting to the resilience of the biosphere."

There are many ideas about what turned Earth into a snowball. One popular theory suggests that minerals released by the weathering of igneous rock sucked enough carbon dioxide from the atmosphere to set off a deep freeze. Perhaps that helped kick off a global glaciation, Dr.

Scientists contend that at least two Snowball Earth glaciations occurred during the Cryogenian period, roughly 640 and 710 million years ago. Each lasted about 10 million years or so. The main evidence of the severity of these events comes from geological evidence of glaciers near the equator.

Scientific dispute. The argument against the hypothesis is evidence of fluctuation in ice cover and melting during "snowball Earth" deposits. Evidence for such melting comes from evidence of glacial dropstones, geochemical evidence of climate cyclicity, and interbedded glacial and shallow marine sediments.

It could happen again, for example after a massive volcano spewing dust and ash high into the atmosphere to reflect away sunlight until everything was covered with ice. As it did back then, life would survive in the seas, but extinction would be the fate of almost every land animal.

Every continental shelf was frozen solid covered by ice 100 meters thick. Viewed from space, Earth would look like a giant snowball.

Snowball earth describes the coldest global climate imaginable - a planet covered by glacial ice from pole to pole. The global mean temperature would be about -50°C (-74°F) because most of the Sun's (Solar) radiation would be reflected back to space by the icy surface.

Most scientists assume that the freezing had something to do with the levels of carbon dioxide in the atmosphere. Just as adding carbon dioxide can make a planet warm up, removing it can make it cool down.

What happened to the Earth 700 million years ago and why? ›

“Imagine the Earth almost completely frozen over,” said the study's lead author, ARC Future Fellow Dr Adriana Dutkiewicz. “That's just what happened about 700 million years ago; the planet was blanketed in ice from poles to equator and temperatures plunged. However, just what caused this has been an open question.

A snowball effect is a process that starts from an initial state of small significance and builds upon itself (an exacerbating feedback), becoming larger (graver, more serious), and also perhaps potentially more dangerous or disastrous (a vicious circle), though it might be beneficial instead (a virtuous circle).

Snowball Earth refers to the contention that in the distant past the Earth froze over from pole to pole. There is considerable evidence to support this contention and the proponents now believe this freezing occurred not just once but a number of times in perhaps more than one episode of freezing and thawing.

The rocks and the models agreed: wobbles in the Earth's axis had caused the planet to escape its snowball phase. So after several million years of being frozen, this icy Earth with a hot atmosphere rich in carbon dioxide had reached a Goldilocks zone – too warm to stay completely frozen, too cold to lose its ice.