Known as the Great Unconformity,
So where did all the rock that belongs in between these time periods go?
HERE IT IS!
Posted on 01/01/2019 7:48:02 AM PST by rktman
The Grand Canyon is a gigantic geological library, with rocky layers that tell much of the story of Earth’s history. Curiously though, a sizeable layer representing anywhere from 250 million years to 1.2 billion years is missing.
Known as the Great Unconformity, this massive temporal gap can be found not just in this famous crevasse, but in places all over the world. In one layer, you have the Cambrian period, which started roughly 540 million years ago and left behind sedimentary rocks packed with the fossils of complex, multicellular life. Directly below, you have fossil-free crystalline basement rock, which formed about a billion or more years ago.
So where did all the rock that belongs in between these time periods go? Using multiple lines of evidence, an international team of geoscientists reckons that the thief was Snowball Earth, a hypothesized time when much, if not all, of the planet was covered in ice.
According to the team, at intervals within those billion or so years, up to a third of Earth’s crust was sawn off by Snowball Earth’s roaming glaciers and their erosive capabilities. The resulting sediment was dumped into the slush-covered oceans, where it was then sucked into the mantle by subducting tectonic plates. (Here’s what will happen when Earth’s tectonic plates grind to a halt.)
(Excerpt) Read more at nationalgeographic.com ...
And, when the tectonic plates grind to a halt, then the gorons will have something else they can whine about.
I have always maintained that global warming is slowing the approach of the next Ice Age.
Got to get the Hemi back on the road.
Too cold for yeast —> no bread, no crust
I blame Lou Malnati.
L
Known as the Great Unconformity,
So where did all the rock that belongs in between these time periods go?
HERE IT IS!
So, where are all of the moraines?
Alien strip miners dah.
They think the moraines got sucked into the mantle through the slush-ocean, I guess.
According to the long term ice core and seabed cores, this is exactly what has happened.
Not sure about those but I can point a lot of ‘morons’.
I read the article. Sorry, I’ll work on that character flaw this year. I never thought I’d read this in a scientific article:
“The easy explanation for this mystery was also a ginormous erosional event, but until now, evidence for one was hard to come by.”
Is “ginormous” a real word now? Ugh.
Yeah, they could have said a “a bigly erosional event” right?
Over at DU
Where did they think our moon came from?
A giant peeled it off, trying to get to the chewy chocolate center.
Moraines can be found today in the northern US with some states having parks dedicated to them. But such moraines are from less than 12,000 years ago during the last glaciation period.
In the middle of flat Iowa, there is an east-west line of hills that mark the edge of the last glaciation. Nothing spectacular, but very noticeable when pointed out.
https://en.wikipedia.org/wiki/Category:Moraines_of_the_United_States
“Altogether, this evidence suggests that a gargantuan erosional event happened at the surface.”
Someone take away that kid’s thesaurus.
“Is “ginormous” a real word now? Ugh.”
Be grateful the author did not use an F-bomb for emphasis.
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