From the “but wait, I thought only CO2 had the power to change the climate” department comes this revelation.
New research suggests that dawn of plate tectonics could have turned Earth into snowball
A research duo from The University of Texas at Austin and UT Dallas have put forward a hypothesis that links the dawn of plate tectonics with “snowball Earth”–a period of climate change that sent the planet into a deep freeze that lasted millions of years.
They expect their hypothesis to generate controversy. Geologists usually place the start of plate tectonics at about 3 billion years ago, while the new hypothesis puts the process in a much younger era known as the Neoproterozoic, which occurred about 542 million to 1 billion years ago.
“If you look at the preserved record, diagnostic evidence for modern plate tectonics involving deep subduction is mainly Neoproterozoic and younger,” said co-author Nathaniel Miller, a research scientist in the Department of Geological Sciences at the UT Austin Jackson School of Geosciences. “But most people think we had this much earlier in Earth history.”
Miller and Robert Stern, a professor in the UT Dallas Department of Geosciences, examined a suite of published scientific data on the geological activity during the Neoproterozoic–the era of snowball Earth–and found a link between plate tectonics and a cooling world.
The research was published online in December 2017 and in the April print edition of the journal Terra Nova.
The Earth is the only planet known to have plate tectonics, with its crust and upper mantle being made up of distinct pieces that move slowly and independently, creating and destroying landforms and producing volcanoes and large earthquakes.
Plate tectonics is one of the most fundamental processes that shape the planet, and most geoscientists believe it has been active for most of the planet’s 4.5 billion-year history. However, according to Miller and Stern, there are a variety of traces in the geologic record that could be consistent with plate tectonics not getting started until the Neoproterozoic.
For example, rock formations, gemstones and chemical signatures known to be associated with plate tectonics date only as far back as this period; and computer models suggest that the Earth didn’t cool to temperatures required for plate tectonic activity until then. The authors also note the geologic interval preceding the Neoproterozoic shows a lack of geological activity–a feature that has it earned it the nickname “the boring billion,” and which could indicate that the Earth was covered by a single lithospheric lid rather than the many moving plates of today.
The overlap in timing between the appearance of these signatures of plate tectonic activity and Earth’s snowball phase led the researchers to think that they could be related, and that the drastic climate change could be a consequence of the Earth’s transition from single lid to plate tectonics.
“This climate crisis could have been caused by a number of proximal causes, but the overall great cause was this revolution in Earth’s tectonic style,” said Stern.
The paper lists 22 proposed ways plate tectonic activity could have brought about global cooling that caused the Earth to be covered from pole-to-pole with ice. They include explosive volcanoes cooling the planet by releasing sulfur into the atmosphere; the shifting of the plates changing the planet’s rotational axis; and increased rock weathering pulling CO2–a greenhouse gas–out of the atmosphere and back into the Earth.
In the study, researchers also considered potential non-tectonic reasons for cooling that came from space–from asteroid impacts, to the collapse of ice rings that could have formed around Earth. If these were the cause of snowball Earth, Stern and Miller’s theory falls apart–but there’s not much evidence to support these triggers.
While all the potential cooling mechanisms were first described in other research papers, Stern said that he and Miller are the first to raise the possibility that each could be related to the transition to plate tectonics–an idea that he describes as radical.
“People have been saying for a long time that we have always had plate tectonics…but I think this might be a failure of imagination,” Stern said.
Graham Shields, a professor of geology at the University College London who was not involved with the study, said that the theory Miller and Stern propose needs more evidence before snowball Earth can be linked to the start of tectonics rather than just a period of tectonic activity.
“How do we distinguish their tectonic onset hypothesis from other hypotheses, most of which are also related to tectonics and the well-established supercontinent cycle,” Graham wrote in an email reply.
The authors note that their paper presents a possible scenario in Earth’s history, and that more research is required to test the link between the dawn of plate tectonics and snowball Earth. They hope that this research will lead other geoscientists to consider the evidence and test the hypothesis.
“Revolutions in our field don’t happen often or very easily,” Stern said. “You plant ideas and then you go and look for more data that either supports them or refutes them.”
###
The paper: https://onlinelibrary.wiley.com/doi/abs/10.1111/ter.12321
Abstract:
When Earth’s tectonic style transitioned from stagnant lid (single plate) to the modern episode of plate tectonics is important but unresolved, and all lines of evidence should be considered, including the climate record. The transition should have disturbed the oceans and atmosphere by redistributing continents, increasing explosive arc volcanism, stimulating mantle plumes and disrupting climate equilibrium established by the previous balance of silicate‐weathering greenhouse gas feedbacks. Formation of subduction zones would redistribute mass sufficiently to cause true polar wander if the subducted slabs were added in the upper mantle at intermediate to high latitudes. The Neoproterozoic Snowball Earth climate crisis may reflect this transition. The transition to plate tectonics is compatible with nearly all proposed geodynamic and oceanographic triggers for Neoproterozoic Snowball Earth events, and could also have contributed to biological triggers. Only extraterrestrial triggers cannot be reconciled with the hypothesis that the Neoproterozoic climate crisis was caused by a prolonged (200–250 m.y.) transition to plate tectonics.
“The Earth is the only planet known to have plate tectonics . . .”
Well that’s going out on a limb,
Nope. But saying it was the only planet with plate tectonics would have been.,
It’s less a comment on the earth than on our state of ignorance.
Admiting what we don’t know is always a good first step in science.
Hard to say if there are any other candidates for it in our solar system – perhaps Io with it’s volcanoes, or Venus, but the surface is so hard to see. Everything else is too cold, or too dead, or too small, or too gaseous.
Good piece of research – the idea of Snowball Earth has always been out there with a big question mark, with everyone acknowledging that it happened but wondering “how in the heck do we explain this?”
He could also be placing the cause/effect cart before the horse. A snowball earth could lead to Crustal deformation and eventual fracturing
I think you missed the sarcasm there. Saying that the Earth is the only planet known to have plate tectonics is like saying that people are the only organisms known to believe in God. It’s true, but utterly irrelevant.
David Middleton on May 8, 2018 at 4:08 am
Admiting what we don’t know is always a good first step in science.
—–
Thoroughly agree.
And honesty is not a good move in compu-science™.
“The Earth is the only planet known to have plate tectonics . . .”
The Earth is the only planet known to have sentient life….
The Earth is the only planet known to have bacon, too—a far more important factoid than either of the other two. (Think about that before heading of to Mars, Elon Musk fanatics.)
Turn the music down:
Alleged alien pig’s head on Mars.
No bacon on mars? strike “trip to mars” off the bucket list.
Interesting theory, but a bit thin on actual support.
That’s the beauty of Earth’s first 4 billion years. With 3 chewed up pieces of a 4.5 billion piece jigsaw puzzle and no idea what the picture on the boxtop was… multiple working hypotheses are abundant.
A bit thin on actual support is something of an understatement. I’ll give these guys that there isn’t that much MesoProterozoic and older rock around to analyze, but my impression is that what there is in places like the Canadian Shield is entirely consistent with plate tectonics having been around since quite early in the Earth’s history. For example, the rocks of the Adirondack Uplift and adjacent Canada are marine metasediments that were apparently appended to the North American (Laurentian) core about a billion years ago. Google “Wilson Cycle”
Is this a refresher undergrad course or a theory?
Tom: you are right that it is an interesting theory, but thin on support, however, the change in Plate Tectonics in the Snowball Earth era was from a floating plate to Plate Subduction. Subduction is interesting because the whole cross-section of the crust melts, not just the base of the crust. It is easy to imagine a lot of volatiles spewed out by the resulting volcanic chains, and a fundamental change in the earths atmosphere. The cooling mechanism associated with this? No useable idea, but interesting coincidence of events in the NeoProterozoic.
Apparently, gobs of sulphur spewed out and caused cooling, but not a single molecule of deviant CO2 came out with it. Or possibly there was CO2 and we had Catastrophic Hot Cooling! AND THAT”S WHAT WE COULD, SHOULD, MIGHT BE PROBABLY HEADED FOR> OMG!
I don’t really buy it, but I guess he’s free to work on it.
There are ophiolite complexes much older than the Neoproterozoic and paleomagnetism indicates that the continents were moving about long before the Neoproterozoic as well.
tty, ophiolite complexes are obducted plates. I grew up (if that is the right term) on the north edge of the Klamath ophiolite terrain, and the variety of ultramafic rocks was amazing. The creek that crossed my parents land had placer gold in it and a chrome mill was next door. My first geology job was for Hanna who was mining/processing a nickel laterite nearby. It is a lot easier to have plates undergo obduction (denser plate overrides less dense plate) than stuffing a whole plate down a subduction zone.
Ron,
Should “terrain” be “terrane”?
Thanks!
Maybe it’s the other way round. Maybe the transition to snowball Earth caused plate tectonics. I’m thinking actually that it’s the most likely explanation: While Earth was super hot, there was a lot of molten stuff and a lot less solid stuff than there is today. As Earth cooled, it gained a lot more solid stuff. At some point, the solid stuff reached a tipping point. [Please note: I only said “tipping point” so that what I said would be accepted without question by certain climate scientists]. Actually, the solid stuff had probably been moving around a lot already, but when there was more of it, bumping into itself was a lot more significant. Plate tectonics would undoubtedly have some effect on climate, but frankly I find some of their suggestions astonishingly ridiculous. Much much more likely, surely, that they have cause and effect the wrong way round.
Mike,
Except that Earth wasn’t super hot during the Archean Eon. Most of the Hadean, yes. Archean, no. Proterozoic, not only no, but hell no. So to speak.
Agree Ron, ophiolites were a convenient PT ‘proofs’ that do not stand up to examination.
And the spaceand geometry requirements for subduction, within a compressional crust and mantld context … yeah, right … same applies to regional dyke swarms, magma chambers and plutons, in what is generally interpreted as longer term compressional crust, active zone, with orogenesis.
Except these are implicitly extensional features, due to their net volume requirements. But oh no, thusts, decollements, folding, overturn, must mean compressional tectonism dominates. Clearly not.
It’s memes, all the way down.
____
@ Felix
Terrain is the correct spelling, we are not going to use your preferred spelling so best you get over it.
https://www.macquariedictionary.com.au/
WX,
It’s not my preferred spelling. It’s the American, and maybe even Canadian and UK spelling. Dunno about those countries. But the US has over 320 million people and Australia 24 million, so our spelling wins.
Besides which, they were discovered in my part of North America, so our geologists get to decide how to spell the phenomenon. They’re our intellectual property.
You’ll just have to cope, 65 million Brits spell it the same way, and that’s where Inglisch originated.
You.lose.biaatch! 😜
As for being your terrain, dream on, obducted opheolite suites were mapped and described in PNG in the 1930s, by Australians. Yank geology ‘apropriates’ and brings up the rear again … 30 years late. 😉
oh yeah, AND yers’ still got its’ interpretation wrong … lol 😁
WX,
American English is closer to the language of Shakespeare than is sissified Received Pronunciation. American English is the English spoken by English immigrants to America, whose descendants outnumber the stay at homes.
Obducted opheolite suites were not recognized as terranes until superior American geologists explained them in the 1970s, based upon studies in my native PNW. Terranes couldn’t be recognized before the discovery of plate tectonics. It appears that you’ve never studied the history of geology.
https://en.wikipedia.org/wiki/Terrane
“The concept of tectonostratigraphic terrane developed from studies in the 1970s of the complicated Pacific Cordilleran orogenic margin of North America, a complex and diverse geological potpourri that was difficult to explain until the new science of plate tectonics illuminated the ability of crustal fragments to “drift” thousands of miles from their origin and fetch up, crumpled, against an exotic shore. Such terranes were dubbed “accreted terranes” by geologists.”
Well that’s where you came to the party 30 years late, as a general concept of accreated terraines was being taught in Australia long before that, and the concept of ‘continental drift’ was taught and generally accepted in Australia in the 1940s,, decades before you lot decided you liked it too, and invented the term ‘Plate Tectonics’ and thus made out that you had made some sort of new and fundamental advance, when you didn’t.
Nope, like proposed obsucted terrain, you merely appropriated it off others, then renamed existing concepts used elsewhere, it to make it seem like it was all American, when it was anything but.
Dream on Felix, the only “history of geology” you’re ‘aware’ of, is the invented one that you were ‘taught’, in which ONLY an ignorant US versions of reality is permitted, and ONLY US misappropriated concepts of others, and ONLY US spelling is permiited.
Scrupulously in-built ignorance and blindness assured.
Don’t make me laugh Felix, we were decades ahead of you lot.
WX,
Please support your assertion with references to Australian geologists who taught continental drift resulting from seafloor spreading in the 1930s.
I know that Australia harbored incorrect contractionists, but who among its geologists proposed the correct mechanism, ie seafloor spreading, discovered by Americans?
Thanks.
Is this the guy you have in mind?
https://en.wikipedia.org/wiki/Samuel_Warren_Carey
Comparing his theory of tectonics, ie an expanding earth (absurd on its face), to the real deal is like saying that Lamarck was right about evolution. It doesn’t count unless you have the mechanism right.
Geologists around the world saw evidence for continental drift, but no one understood how it worked until the USN discovered seafloor spreading, hence no one could explain how terranes accreted.
Besides which, it just makes sense to use a different word to label a terrane as opposed to “terrain”, which has so many other meanings.
I know I will be laughed out of the forum with this but plate tectonics started with Noah’s flood as mentioned per the Bible. As very few know but the original specs for earth was the crust sitting on a layer of water then the mantle. The crust split aka Great Atlantic Ridge (and Pacific) and all that water spurted out .As this water depleted the crust resettled but broke up into what we now as Plate Tectonics.
Have a good time. 🙂
Where do the turtles fit into this model?
& dont forget the four elephants
Re “where do turtles fit in this model” … Turtles are the foundation … turtles all the way down.
In turtle structures.
http://www.searchanddiscovery.com/documents/2008/08092webster/ndx_webster.pdf
“I know I will be laughed out of the forum with this but plate tectonics started with Noah’s flood as mentioned per the Bible”
“Where do the turtles fit into this model?”
on the ark with the rest of the animals, obviously 😉
Steve,
Sorry, but I’m laughing.
Plate tectonics started around three billion years ago. The Noah story, in its original Sumerian myth of Eridu, was written down around 3600 years ago, but possibly existed before then in oral tradition.
The Flood legend is a mythical explanation for the rainbow, not science or history. It might however be based upon a particularly bad flood in the Euphrates-Tigris system, in which a farmer put his family and domestic animals on a raft. Maybe a donkey, some goats and chickens, but no giraffes, kangaroos or dinosaurs bigger than the chickens.
Felix you have convinced yourself that you are correct and anything else is wrong I guess.
Steve,
I go by physical evidence, not ancient myth. All the evidence in the world convinces me that Earth was not entirely under water some 4500 years ago. Whence came 3.5 times all the water in today’s oceans, and where did it go?
How did land animals get from Australia and the Americas to Noah’s house in the Middle East? How did billions of species of often large animals fit on the Ark, survive a year and be cared for by eight humans, especially as there were seven of each clean animal, not just pairs? How did sea animals adapted to salt water survive so much fresh water? How did an olive tree grow so rapidly after the initial subsidence of all that water? It must have been atop a very high mountain, where trees don’t grow, let alone an olive tree. Presumably ravens are unclean, so good luck for the surviving raven finding its missing mate.
Sorry, but it’s laughable.
And besides not being able to feed and water billions of animals, how did Noah’s family keep the carnivores from eating the just released herbivores? Were they given a head start? What did they eat until vegetation had time to get started up again?
Do you really believe that this myth actually happened?
PS: Ravens figure even more prominently in myths from northwestern North America. ie the Raven Tales.
There was also the flooding of the Black Sea basin that also occurred around the same time.
Ah, but you skip over the Black Sea hypothesis there.
I find it more satisfying myself to base speculation on the empirical evidence that we humans have collected. But I cannot disprove the notion that such evidence was “planted” for us to find and be misled by. (Although I can poke holes in the Christian creationists that espouse that notion – it does not jibe with their other assertions about the nature of Deity. It actually fits better with other theologies, such as the Norse system, with an acknowledged “practical joker God.”)
WO,
The Black Sea hypothesis requires cultural memory over thousands of years and transmission over a thousand miles. The Sumerians lived far from the Black Sea and millennia later than the hypothetical event, which in no way corresponds to the Flood myth, based upon 40 days of rain and ground water eruption. OTOH, we know that the Euphrates, like the Nile, naturally floods every year.
Yes, I can’t rule out a Trickster God, Who made the universe look as if it were 13.7 billion years old, just to test our faith. But then, would such a deity–deceptive and cruel–be worthy of worship? And if this same Cosmic Jokster also is responsible for creating species, then It is also disgustingly cruel.
And incompetent, given how idiotically living things are “designed”.
@ Writing Observer
” … But I cannot disprove the notion that such evidence was “planted” for us to find and be misled by. …”
______
The mother of all conspiracy theories, all the rest are pikers. Yet we can see light from stars in our own galaxy that are ~100,000 light years away and millions of external galaxies, billions of light years away.
Cognitive dissonance at its best.
Assume that half the 30,000 feet of water to cover “the highest mountains” flooding Earth “in the six hundredth year of Noah’s life, on the seventeenth day of the second month” came from “the springs of the great deep burst(ing) forth”, and half from “the floodgates of the heavens (being) opened; And rain (falling) on the earth forty days and forty nights”.
That means 15,000 feet, or 180,000 inches in 40 days, or 4500 inches per day. Sound reasonable to you?
While the hypothesized Black Sea flood c. 7600 BP is an improbable source for the myth (for a number of reasons, one of which linked below), it’s just barely possible that some memory remained of the final inundation of the Persian Gulf shore, when MSL reached its Holocene high stand, either during the Climatic Optimum more than 5000 BP or the Minoan Warm Period, c. 3500 BP.
https://www.sciencedaily.com/releases/2002/06/020617074814.htm
But more likely is simply a bad river flood season for which a farmer was prepared.
Had a global deluge indeed occurred a mere 4500 years ago, then there would be evidence for it everywhere. Instead, there is none anywhere.
Snowball Earth is an hypothesis not proven fact.
1 – Lord Kelvin calculated the age of the Earth based on how fast it has cooled. link His calculation was wrong but he had a point in that the planet started very much hotter than it is now.
2 – The Earth is losing its atmosphere at a slow rate. link How thick did the atmosphere used to be? The first approximation to surface temperature is determined by the temperature at which convection will start and will carry heat away from the surface. The thicker the atmosphere the higher that temperature. That, not CO2 absorption of radiation, explains why Venus is so hot … much hotter than would be predicted by its nearer proximity to the Sun.
3 – The easiest explanation for dinosaur flight is a denser atmosphere than is the case at the present. link
I’m skeptical. It’s quite possible that the planet was too warm for snowball Earth to have happened. The planet itself was hotter and the atmosphere was thicker.
So, if we replenish the lost atmosphere with enough carbon dioxide, plants will convert that carbon dioxide to oxygen. We will all have plenty of oxygen to breathe, and the problem of diminishing atmosphere is solved. Grant money, please. 🙂
As an added bonus, with sufficient carbon dioxide in the atmosphere, we preclude any future possibility of another ice age. More grant money, please. 😀
Put me down for some of that grant cash, okay? I need to get the stove fixed or replaced.
More oxygen is not good. Awful fires.
More O2 —> Big Bugs too! https://www.sciencedaily.com/releases/2010/10/101029132924.htm
Earth’s atmosphere used to have much more CO2. Where do you think all those limestone deposits came from? And life probably caused much of their precipitation.
But unlikely Earth has lost significant atmosphere over past 3.5 billion years, because the 15N/14N ratio in our atmosphere is not significantly fractionated, as on Mars (or the 2H/1H on Venus) and as slow loss would produce. However, very large atmospheric losses due to giant impacts in early Earth history cannot be ruled out.
DAvid
I am with you I hate bugs! the bigger they are the more i hate them.
Indeed, I agree with CommieBob on this one.
http://sciencenordic.com/earth-has-lost-quarter-its-water
Someday the Earth sciences will get back on track.
And not only would a denser atmosphere help pterosaurs fly, but it would help sauropods function at that size as well.
Exactly. This article is a hypothesis about a hypothesis.
But it’s such a cool hypothesis!
That was cold.
another theoretical possibility for pterosaur flight is that, with no large mountain ranges like the Himalaya to break up air currents caused by earths rotation, pterosaurs were able to live in areas which had a constant 30 – 40 mph wind blowing, never ceasing. If this happened, they could have functioned like large kites which had the ability to direct their motions.
the theory, in this case, would be that such a wind blew in equatorial regions for many millions of years.
The atmosphere we see today is too chaotic not to have extended periods of calm. I see no reason why the atmosphere would be so different in the past. If they needed to fly to feed then any extended period of calm would be fatal. So, I don’t buy that theory.
“The atmosphere we see today is too chaotic not to have extended periods of calm”
In much of the Southern Ocean periods of calm are extremely rare. Which is a good thing for albatrosses which can’t take off in a complete calm (verified by personal observation during a rare short calm in the Beagle Channel).
“The easiest explanation for dinosaur flight is a denser atmosphere than is the case at the present.”
If I understand correctly, ‘Flying dinosaurs’ are birds — which demonstrably do just fine at current atmospheric pressure. I’m guessing that you’re thinking about pterosaurs which (probably) weren’t dinosaurs. Those critters had huge wings. My understanding is that little is currently known about how they evolved, but I’d guess that they evolved from non-flying reptiles in much the same way that bats presumably evolved from more generalized mammals. I personally don’t have much trouble imagining a tree dwelling critter with membranes to help it glide from tree to tree eventually evolving into a true flying reptile. I’ve often seen ordinary Grey Squirrels jump from tree to tree to tree in order to avoid predators (dogs). The squirrels glide pretty well despite not appearing to have much in the way of flying adaptations.
So no, I don’t think a denser atmosphere was required for flight to evolve..
You are right.
The denser atmosphere is the easiest explanation for why something the size of the flying dinosaurs could fly. The link I supplied is really good.
No a denser atmosphere was not required for flight to evolve, But I suspect that a denser atmosphere may be required to allow flight by pterosaurs weighing between 165 and 1000 pounds.
https://theconversation.com/pterosaurs-should-have-been-too-big-to-fly-so-how-did-they-manage-it-60892
I saw a documentary a number of years ago about a team of paleontologists and engineers who built and flew arradio controlled model of a pterosaur. They tried to get both the size and weight to be accurate.
And bumblebees can’t fly.
Alan — The really big pterosaurs may indeed have weighed in around 500kg. But they had a wingspan of 10m which is only slightly less than a Cessna 172 with a maximum takeoff weight around 1100kg (about 2400lb).
(No, I don’t have the slightest idea how those things got into the air. Climbed something really tall, closed their eyes, then jumped and flapped their wings?)
So instead of accepting that the atmosphere was thicker — based not only on this circumstantial evidence but on isotopic evidence and models — let’s invent some crazy ideas for how a 500 kg animal could fly. Maybe they could run at 150 mph, like a Cessna down a runway, before taking off.
“And bumblebees can’t fly.”
And myths live forever. especially on the internet.
“And bumblebees can’t fly.”
They can because of the viscosity of air. This is negligible for larger animals but not for insects where it makes the rotation of air around the wing extend slightly beyond the wingtips. This means that the effective wing-span becomes slightly larger than the geometric. Somewhat simplified, they fly thanks to wing-tip vortices.
Some specialists have concluded that the biggest azhdarchid pterosaurs, with 36-foot wingspans, could still fly, but rarely did so once they were big enough to survive on the ground. (Note headline also mistakenly calls them “dinosaurs”. They were close relatives of dinos, on the same line of the archosaurs, as opposed to the crocodilian line.)
https://www.inverse.com/article/33199-biggest-flying-animal-ever-pterosaur-azhdarchid-quetzalcoatlus
Here seen feasting on young sauropods:
IMO, there is no need to invoke the slightly higher O2 content of Late Cretaceous air to explain pterosaur flight. Once airborne, they were like big gliders, riding the thermals.
The flying bird with the longest known wingspan, at 24 feet, was a condor relative from 28 Ma. The biggest living wandering albatrosses span almost 12 feet.
http://i.dailymail.co.uk/i/pix/2014/07/07/article-2683264-1F75238500000578-343_634x594.jpg
Here’s a paper arguing that the atmosphere must have been denser not only to allow for 75 to 500 kilogram fliers, but also to keep the largest sauropods from passing out due to a lack of oxygen and blood pumped to the brain.
http://www.doiserbia.nb.rs/img/doi/1451-9372/2006/1451-93720602116L.pdf
Seconding the notion that a complete snowball earth (despite the picture) is very much in doubt. Only Andrew Lacis, with his preposterous model, has created a snowball earth.
Thinking it is better to validate that the creature existed before speculating how it evolved.
Right, commieBob!:
This alleged research is a hypothesis regarding a hypothesis, and founded on ignorance and misunderstanding.
e.g. Their Earth is the only tectonically active planet assumption. Both Mars and the moon have recorded marsquakes and moonquakes; Io demonstrated volcanism, lava flows have been identified on a number of planets.
Yet these characters assume facts regarding Earth and our solar system that impairs any ability to view information dispassionately.
commieBob, good points. Snowball Earth is far from ‘established science’. From what I read on Wikipedia, it does not appear to be widely accepted by the experts.
There was certainly at least three episodes of very extensive glaciation in the Neoproterozoic, but almost certainly not a real “Snowball Earth”. The existence of ice-rafted debris throughout marine deposits of this age in e. g. Oman indicates that glaciers remained active and calved icebergs into the ocean. On a “snowball Earth” the hydrological cycle would have stopped and glaciers would literally freeze in place.
I’ve read that the speed at which ice freezes determines its level of transparency. Life didn’t go extinct, photosynthesis continued, and photosynthesizing life didn’t have to start again from deep sea vents – or deep in the crust (where it remained warm enough).
Jeff in Calgary May 8, 2018 at 8:58 am
That at least near global glaciations happened repeatedly is accepted by “experts”, ie sea level land ice at low latitudes. The evidence is overwhelming. However, Earth may never have suffered an “Iceball” episode, in which frozen water encrusts the whole planet. Today, geologists think that most such intervals were “Slushball Earths”, with at lest seasonally ice-free tropical seas. The Huronian however might have come close to an iceball, with solar output 20% lower 2.2 Ga than now.
meteorologist in research May 8, 2018 at 11:02 am
The survival of life isn’t a problem. Organisms live under the East Antarctic Ice Sheet and within it. Both photosynthetic and anaerobic microbes would have survived the worst Snowballs, even without the refugia of hydrothermal vents. Besides which, as noted, there would always be some open seawater under the Slushball scenario.
It’s possible that life first arose in tiny water pockets within (possibly dirty) ice, which would have concentrated nucleotides and amino acids, facilitating the polymerization (formation of long chains) of these monomers into nucelic acids and proteins.
Somebody correct me if I’m wrong, but I think the “snowball earth” is likely, but not certain. IIRC, the principle evidence has always been the presence of “dropstones” in very ancient sediments that appear from magnetic signatures to be near equatorial. Dropstones are rocks picked up by glaciers and rafted out onto a body of water where they drop to the bottom when the ice melts.
BTW, That would seem to require glaciers, liquid water and enough warmth to eventually melt (sea?) ice.
A problem that should be pointed out is that we don’t really know exactly why the Earth has a magnetic field. Neither do we know why the field is roughly aligned with the Earth’s spin axis. So, there remains a (likely small) chance that at “Snowball Earth” time the magnetic field wasn’t aligned with the spin axis and we’re really looking a sediments deposited closer to the poles than we think.
Don,
The evidence doesn’t rely solely on paleomagnetism. During the identified episodes, evidence of glaciation is found everywhere in rocks of those ages.
The denser atmosphere link on flight was interesting, however it was incorrect in several areas regarding the theory of flight and aircraft design. it also neglects the average layman’s mistake: No matter how efficient an object is at flight in a particular regime (altitude, flight speed) it still must take off and land. That means it must also be able to transition to and from its “preferred” flight regime. He also completely ignored ground effect flying which allows pelicans and similar birds to maximize power savings.
Correct. The Soviet Ekranoplan or “Caspian Sea Monster” couldn’t fly without the wing in ground effect.
I’ve read somewhere, don’t remember where, that there was more than one episode of snowball Earth. And there are those illustrations that show continental placements in the current modern form, which is a hoot.
Whatever, it’s all theories, you know. Unless Dr. Who shows up with the Tardis for a time slip trip, we can go on theorizing ad infinitum.
Why was it ever a ‘stagnant lid’?
Was/is Earth an accretion of ‘stuff” subjected epic bombardments (where did the Moon come from) plus a shed load of radionuclides that were still fairly young.
It formed a skin at a fairly young age and the internal heat from the nuclides started Plate Tectonics at an early age – lets give it 1 billion years.
Volcanoes and more stuff falling in created an atmosphere and life started then.
But life depends on food and the original and best food comes from rock itself. Phosphorus, calcium, magnesium, sodium etc etc (Mostly metals = alkaline chemistry)
Doh, is that why seawater is………………
You know me, I assert that plants and dirt are significant controllers of what we imagine to be climate.
Over the course of time, the food on the surface gets used up. It is dissolved by the very life processes it supports and finishes up in the ocean. It don’t come back.
So, life must inevitably decline as the supply of metals fades away.
Until or unless something replaces the supply.
Enter volcanoes and mountain building – huge belches of fresh food for the plants/bacteria/whatever.
This is where Mars went wrong. It had water, it had life but no Plate Tectonics to supply new/fresh nutrition.
So no plants = no water retention in the soils = desert landscape = crap climate = increasing cold > snowball.
And there is a truly horrible finale to a positive feedback – high albedo keeps things frozen.
So for Mars, what atmosphere it had (similar to ours now) simply and slowly evaporated, lighter fractions first, and was blown away in the solar wind. So what’s left now is a tiny fraction comprising the heaviest of the common atmospheric gases = carbon dioxide.
For Mars, did that happen at least 3 billion years ago?
The same would have happened here on Earth but plate tectonics puffed up volcanoes and pushed up mountain ranges. It lowered albedo in places and gravity let the ice slide off the mountainsides and things recovered.
But it does depend on a stretch of open water being maintained, around the equator obviously.
Life would have retreated back into the water. (Why is our blood so salty?)
Planetary rotation would have set up big ocean currents, hence winds & weather that would have moved the solar heat captured in that water to places at higher latitudes.
Glaciers would be bring ground up fresh rock to the coast, enabling life to move back out of the water. As fertile dirt growing lots of plants control climate, a beneficial positive feedback would result.
Plants and life would reclaim the continents.
Of course it is a bit of a lottery and sometimes the Plate Tectonics would result in a stalling of ocean currents, as happened when South America bumped into North America. Heat dispersion would slow and hence, the Snowball Earth would result.
But of course as obviously happened, Plate Tectonics realised its error, moved the continents a bit more and let the water (and heat) start flowing again.
Alerts readers will see there’s a possibility of a Cycle going on here, so what might be the frequency of snowball type events.
How long does dirt last?
Being in Nottinghamshire as I am, I can see some very fertile dirt ‘still on the ground’ hence 10+ tonne per hectare wheat yields.
But there is humongous amounts of coal under the place.
Maybe 350 million years ago, the dirt was so fertile that plants grew so fast, decomposition couldn’t happen fast enough. The old plants got buried and fossilised.
So. Do we say that The Cycle is 500 million years?
Maybe there has been previous cycles – EXACTLY as Gavin was looking for recently.
Everyone thought him crazy. (Holy Cow, where does that put me?)
Is Earth 4.5 billion years old, do we say we’re maybe now seeing the 6th or 7th cycle?
What happened in previous ones?
Did people evolve? Lets hear a solid reason why they should not have.
Did they invent space flight?
Did they send off explorers?
Who was James T Kirk modelled one? Just why did he have to indulge a game of Tonsil Tennis with good looking alien cougars at the end of every episode?
Where are those explorers now? James Kirk suggests what they’re up to.
Did the first ones set off 3 billion years ago – did they achieve even a paltry 10% of light speed. Relativity is only a real problem at 90%+ of light speed.
Have we got ‘early ancestors’ 300 million light years away and still rolling?
Sends a shiver and makes the hairs stand up doesn’t it………..
Our problem, apart from eating too much sugar, is that the radionuclides are now 4 billion years older than they were……………………
Peta; while there is substance for many of your claims, your ocean end reservoir is not.
Even oceans have short lifespans compared to Earth.
Some of the ocean debris gets bulldozed onto continental borders.
Some ocean debris gets uplifted through tectonics.
Some ocean debris gets subducted.
Some ocean debris gets covered by sediments and alluvial debris.
Continents collide.
Continents rift.
Continents rearrange through faults.
Then there is that exhaustible claim regarding surface metals and exposures.
Earth has abundant supplies of minerals and metals, virtually everywhere.
A fact well demonstrated by Continental Shields where rocks that are billions of years old are exposed. Billions of years of weather, wind, erosion, etc. and those rocks are not depleted in any sense of the word.
“Life would have retreated back into the water. (Why is our blood so salty?)”
Peta, are you thinking of the hypothesis that our blood retains the salt levels present in the seas at the time that land animals evolved?
That hypothesis hinges on the idea that salt in bodily fluids of sea life = salt level in sea water during all ages.
If that hypothesis were true, today’s marine fish would be much saltier than they are because the salt levels of the seas has continued to increase over time.
Secondly, what of the hypothesis that land animal life began via lung fish crawling out of fresh water ponds/streams during drought season?
I don’t buy either hypothesis, they just show speculation is easy.
SR.
Tetrapods evolved from lobe-finned fish related to lungfush, which are genetically the closest to us tetrapods. They evolved from marine lobe-fins, not from freshwater pond dwellers. Fins evolved into feet and hands, via further calcification of cartilaginous fin rods into bones, to help ancestral tetrapods rise up and gulp air out of anoxic shallow water, then improved over time, permitting movement onto land to exploit the previously inaccessible food resources there.
Every line of evidence supports this conclusion, to include fossils, genetics, embryology, anatomy, physiology and biochemistry.
http://www.evolution-textbook.org/content/free/figures/10_EVOW_Art/29_EVOW_CH10.jpg
A good book on the topic:
https://www.amazon.com/Gaining-Ground-Second-Evolution-Tetrapods/dp/025335675X
Sarcopterygian is the scientific name for lobe-finned fish, which already have the tetrapod limb arrangement of one large bone close to the body and two smaller ones farther away.
By the time you get to early tetrapods, they could indeed have lumbered across the land enough to move from pond to pond or out of rivers. But their lobe-finned fish ancestors were shallow marine or estuarine animals. Our lungfish relatives are practically amphibians, since they can encase themselves in mud to survive dry spells on the continents of South America, Africa and Australia. The Australian genus most resembles ancient lungfish. Lungfish boast the largest of vertebrate genomes.
“Tetrapods evolved from lobe-finned fish related to lungfush, which are genetically the closest to us tetrapods. They evolved from marine lobe-fins, not from freshwater pond dwellers. Fins evolved into feet and hands, via further calcification of cartilaginous fin rods into bones, to help ancestral tetrapods rise up and gulp air out of anoxic shallow water, then improved over time, permitting movement onto land to exploit the previously inaccessible food resources there.”
So, you say marine lobe-fins developed feet and hands so they could rise up out of anoxic shallow water? I have heard of anoxic marine water – at depth in certain situations such as the Hood canal, but never in shallow water. Shallow water is where waves break. Breaking waves are great oxygenators.
SR
On the timing – About 2.3 Billion Years Ago, a Firehose of Oxygen was Released Into the Atmosphere https://www.princeton.edu/news/2018/03/22/two-billion-year-old-salt-rock-reveals-rise-oxygen-ancient-atmosphere
Then : Study zeros in on plate tectonics’ start date
https://phys.org/news/2016-01-zeros-plate-tectonics-date.html
Continents require granite from subduction and water.
Did the GOE , great oxygenation event, basically kill all previous species, that sediment subducted to become granite ? Did that biosphere event , much faster than thought, actually start tectonics? In other words has Earth tectonics because of an active biosphere ?
Or… Earth has tectonics because of water and a biosphere because of tectonics and water. With so few pieces of the Precambrian puzzle, they can be assembled in almost any way imaginable.
https://www.geosociety.org/documents/gsa/timescale/timescl.pdf
The Cenozoic covers only about 65 million years.
The Mesozoic just under 200 million years.
The Paleozoic a bit over 260 million years.
The other ~4,000 million years are lumped into the Precambrian.
I brought up Granite, covered in 1 link but not the Lead. Anyway tectonics and biosphere are likely not coincidence. Or tectonics on another planet (or moon?) might indicate biospheric activity….
I definitely think tectonics and the bioshpere are connected… It’s the “how” that will probably be a mystery for a long geologic time.
Huronian glaciation Snowball Earth (1 of at least 5) has been linked to the GOE, putting it before tectonics.
Paleomap Project
Late Precambrian Supercontinent and Ice House World
http://www.scotese.com/earth.htm
Good images of early earth continental placement.
So by extension the Carboniferous was the lack of plate tectonics?
Those were *good* plate tectonics —> Goldilocks climate, Goldilocks CO2… Nirvana on Earth right up until the Permian extinction.
It must be said that the Snowball Earth hypothesis gives strong support to climate warming by greenhouse gases. If the Earth goes into snowball condition the albedo goes to like infinite, so the only conceivable way to escape such condition is through the build up of non-condensing GHGs, causing enough warming to melt the ice.
Of the three hypotheses explaining tropical glaciation, Snowball Earth, very high orbital obliquity, or markedly non-uniformitarian geomagnetic fields, the Snowball Earth is the one best supported by evidence.
It appears also, that the climate of the Earth became more stable at the end of the Proterozoic. Biology may have played a role on that. It is not only that the planet has allowed the development of life, but life appears to have also shaped the planet to become more hospitable to itself, and climate stabilization is a big part of that. Evolutionary explosions were the result.
Plus… Covering all of the rocks with ice tends to put a damper on weathering removing CO2 from the atmosphere… Covering the oceans with ice tends to prevent gas exchange with the oceans… Covering the plants with ice means you’ll need to get new plants when the ice melts…
Did a gamma-ray burst initiate the late Ordovician mass extinction? https://arxiv.org/abs/astro-ph/0309415
The extinction is linked to sudden glaciation, caused by a GRB (nearby supernova of some kind.
By the way 18 nearby supernovas in the last 8Myr
Recent near-Earth supernovae probed by global deposition of interstellar radioactive 60Fe
http://www.nature.com/articles/nature17196
might have something to do with recent glaciation patterns.
This statement should be rephrased. We don’t know if the extinction was caused by the glaciation, nor if the glaciation was caused by the gamma-ray-burst.
Articles that have a question for title are generally a lot more speculative than usual. The most likely answer to the question is NOT.
Another possibility is with all the water covered with ice, new snowfall stops.
As a result continued volcanic activity slowly covers all that ice with a layer of soot, which melts the ice ending the snowball earth episode.
CO2 is just too weak a GHG to end the snowball earth episode.
Before oxygen started to accumulate in the atmosphere, methane must have been pretty stable.
Which would make CO2 even less important.
“If the Earth goes into snowball condition the albedo goes to like infinite, so the only conceivable way to escape such condition is through the build up of non-condensing GHGs, causing enough warming to melt the ice.”
There are at least two other mechanisms. One uncertain: a Large Igneous Province would probably eject enough volcanic ash to lower albedo. And one dead-certain: a Chicxulub-size impact (which occurs every few hundred million years, but probably more frequently in the Precambrian) virtually instantly cover the entire planet with at least a few millimeters of near-black fallout.
Also I strongly doubt that any amount of CO2 could get the planet out of a “snowball” state. CO2 just hasn’t wide enough absorption bands:
No matter how much CO2 there is in the atmosphere those bands will only widen very slightly (due to pressure broadening).
Javier,
That’s not the only way to get out of a Snowball Earth, and indeed the least likely.
More probable is simply plate tectonics. As the continents rearrange, volcanism and land drifting closer to the Equator would melt the ice.
Well, it is a matter of opinion, since we are talking about hypotheses, however it should be noted that glaciations suppress volcanic activity, so a Snowball Earth might have less volcanic activity than otherwise. On the opposite side volcanic activity was much higher when the Earth was younger.
True that ice sheets suppress volcanoes, but those under floating sea ice might have been even more active as a result.
But IMO the main cause is simply tectonic shifts. The Huronian glaciation lasted 300 million years, so lots of time for plate movements.
IMO GHGs cannot explain the end of global glaciations.
If the atmosphere at the time had very low levels of water and carbon dioxide, perhaps due to the lack of tectonic activity, then it would be very cold at the surface.
I don’t like this theory much, but with so little evidence at the period, who’s to say it wasn’t unicorn farts. The part I don’t like is mechanism – if there was a cap strata initially locked into place, what caused it to break up and start moving about? ( a meteor? a comet? the aforementioned unicorn flatulence???)
Unicorns never existed… So, we can at least rule one hypothesis out… /Sarc
Of course unicorns existed, and they do exist today.
http://1.bp.blogspot.com/_hEYNBEBYxBA/Ss5cmRpzRPI/AAAAAAAAAgI/FMMMerZnHHw/s400/Sport+Fishing+With+Sakwinder+Narwal.jpg
http://dinoanimals.com/wp-content/uploads/2016/05/Indian_rhinoceros8.jpg
You forgot this one…
http://www.artofobama.com/wp-content/uploads/2008/12/obama-unicorn-0-550×413.jpg
Some people get mixed up between Unicorns and Pegasus. First off, Pegasus is a horse with wings. Second, unicorns are fictional.
Pegasus used to be they symbol of Dallas TX because of Mobil Oil (originally Magnolia Oil Company) was headquartered there…
Recently, this has become the symbol of Dallas…
Vandalized and abandoned bike-share bicycles.
“Unicorns never existed… So, we can at least rule one hypothesis out”
Reminds me of a story:
“What do you do for a living?”
“I’m a unicorn hunter”
“Is it true that you have to use a virgin as bait to catch a unicorn”
“Yes”
“They must be pretty rare”
“Yes, very, and unicorns aren’t that common either”
LMAO!!!
Yes, there’s a little problem of the energy input needed to get the mantle to move plastically from stationary, as it would melt both the mantle and the crust, and make the planet incandescent.
No, we know fhat didn’t happen, so that means the mantle must have been mobile, all along.
No, as that would require horizontal decollements in the asrlthenospere, so the plates above could stay static, while the mantle moved below it, … for 4 billion years.
No, that didn’t happen either, as the staggering friction of 4 billion years of doing that, would have totally melted the low thermal conductivity self insulating crust above. So that also didn’t happen.
But then the gurus say plates ‘drift’ independently over the mantle convection circulation below. Well, despite its lack of difference to the above, we know that is not occurring, because mantle toography shows that continents have deep welded “continental root” structures, that extend BELOW the asthenosphere.
So continents can not be ‘drifting’ on the mobile mantle below, tomogrphy shows they are welded and embedded in the mantle under them—the contiguous continental-root structure is continuous into the mid-mantle levels.
In which case, crust only moves in lock step with the connected mantle roots below then.
Which is a problem, as it means the mantle can not be independently overturning, via supposed convection cells, or else there would be no continental-root structures seen below the continents … gosh darn it.
Thus the standard accepted driving mechanistic explanation of mutual global primary ‘plate movement’ through time also can not be occurring! … oh dear … I want my mommy!
Thus the Plate Tectonic concept is falsified. Yet another generally acceptted too-cute pat meme that is also (rather annoyingly) shockingly absent.
What is geodynamically right we still don’t know.
But that should NOT be so! But it is.
It’s actually really embarrassing, not to mention damned inconvenient and disconcerting, thus it’s simply not being admitted to.
Nope, so we batter on with our preferred regional ‘working geotectonic interpretations’, but with no viable cohesive global theory of geodynamics, that stands up to a basic fact-check, in 2018.
Such is the nature and blindness of paradigm addiction.
The origin of plate tectonics will be the next big discovery in physical geology after Marie Tharp discovered the Mid-Atlantic Ridge that established plate tectonics
http://exploration.marinersmuseum.org/wp-content/uploads/sites/7/2017/07/Tharp.jpg
The mid-Atlantic ridge was discovered by the Challenger expedition in 1873. I wrote about it recently at WUWT.
The discovery of sea floor spreading on the MAR was what provided the mechanism for “continental drift”.
Father of Seafloor Spreading, USN RADM:
https://en.wikipedia.org/wiki/Harry_Hammond_Hess
A pioneer of modern oceanography, Tharp was the first to map the unseen topography of the ocean floor on a global scale. Her observations became crucial to the eventual acceptance of the theories of plate tectonics and continental drift in the earth sciences.
Piecing together maps that they made, she and colleague Bruce Heezen revealed a 40,000-mile underwater ridge girdling the globe. With the discovery, they laid the foundation for later work that showed the sea floor spreads from central ridges and that the continents are in motion with respect to one another — a revolutionary and controversial theory among geologists at the time.
When Tharp started piecing together the profiles, she noticed that it was not the line of mountains that formed the most continuous feature through the middle of the North Atlantic, but a cleft running down the center with peaks on each side. She thought it might be a rift valley like the one found in East Africa, an idea that would support the budding hypothesis that the continents move across the surface of the Earth. Based in part on the incontrovertible pictures she provided, the concept of plate tectonics moved into the realm of legitimate debate and later into the mainstream of earth science.
In 1959, Tharp and Heezen completed their first map of the North Atlantic. In 1961, they completed the South Atlantic and in 1964, the Indian Ocean. After Heezen died in 1977, Tharp focused her energy on completing a comprehensive view of the world’s oceans. The World Ocean Floor map was published later that year by the Office of Naval Research and is still in wide use today.
http://www.columbia.edu/cu/news/06/08/tharp.html
COULD is not a very useful term in science, and this new report is full of coulds.
“Could have occurred” simply means that physical laws do not prevent its occurrence, not any high probability of actual occurrence. Could is less probable than maybe. Climate study is increasingly full of these kinds of useless comments — thought speculation for effect more than based on solid evidence.
“Could” means that something is consistent with the observations. It’s a bit more definitive than just “not impossible.” Unique solutions are few and far between in the Earth Sciences, so “could” gets used a lot.
What Scientists really mean when they say things.
Authoritative statements in scientific journals should not always be taken literally. I.J.Good has made a collection of them.
“It has long been known that…”
I haven’t bothered to look up the original reference.
“While it has not been possible to provide definite answers to these questions…”
The experiment didn’t work out, but I figured I could at least get a publication out of it.
“High purity …”, “Very high purity…”, “Extremely high purity…”, “Super high purity…”
Composition unknown except for the exaggerated claim of the suppliers.
“…accidentally strained during mounting”
…dropped on the floor.
“It is clear that much additional work will be required before a complete understanding…”
I don’t understand it.
“Unfortunately a quantitative theory to account for these effects has not been formulated…”
Neither does anybody else.
“It is hoped that this work will stimulate further work in the field.”
This isn’t very good, but neither is any of the others on this miserable subject.
“The agreement with the predicted curve is excellent” …good” …satisfactory” …fair.”
Fair. Poor. Doubtful. Imaginary.
“As good as could be expected considering the approximations made in the analysis.”
Non-existent.
“Of great theoretical and practical importance.”
Interesting to me.
“Three of the samples were chosen for detailed study.”
The results on the others didn’t make sense and were ignored.
“These results will be reported at a later date.”
I might possibly get around to this some time.
“Typical results are shown.”
The best results are shown.
“Although some detail has been lost in the reproduction, it is clear from the original micrograph that…”
It is impossible to tell from the micrograph.
“It is suggested…”, “It may be believed…”, “It may be that…”
I think.
“The most reliable values are those of Jones.”
He was a student of mine.
“It is generally believed that…”
A couple of other guys think so too.
“It might be argued that…”
I have such a good answer to this question that I’ll raise it.
“Correct within an order of magnitude.”
Wrong.
“Well known.”
(i) I happen to know it, or (ii) well known to some of us.
“The reason is, of course, obvious.”
(i)Not in the least, or if it really is: (ii)I was not the first to think of it, but I think I got it independently.
From “Eureka: A book of scientific anecdotes”, by Adrian Berry.
http://people.cs.uchicago.edu/~dinoj/scilies.html
Loved these. “Correct within an order of magnitude” pretty much describes AGW.
AGW is rarely that correct.
Thanks for those quotes David. Too funny!
What’s the point in being a scientist if you can’t laugh at yourself? 😉
A few more
“It is generally agreed that…”
My thesis supervisor thinks
“NN is thanked for his helpful suggestions”
NN actually did all the difficult bits
“a Bayesian analysis shows…
It was too difficult to fiddle ordinary statistics
From the “But wait, I thought CO2 could by no means change the climate” department comes this blog babble:
ways plate tectonic activity could have brought about global cooling that caused the Earth to be covered from pole-to-pole with ice
would include
increased rock weathering pulling CO2–a greenhouse gas–out of the atmosphere and back into the Earth. ?
Hilarious.
Rock weathering does pull CO2 out of the air and puts it back into the Earth. It’s called the carbonate-silicate weathering cycle…
http://faculty.buffalostate.edu/sabatojs/courses/GES389/carbon1.jpg
http://faculty.buffalostate.edu/sabatojs/courses/GES389/carbon2.jpg
http://faculty.buffalostate.edu/sabatojs/courses/GES389/supplemental.html
The degree to which the carbonate-silicate weathering cycle affects the climate is a total SWAG (scientific wild-ass guess).
gammacrux does not understand the skeptical viewpoint at all. Nor does he understand that a quotation does not necessarily reflect the views of the person citing the quot.
The start of plate tectonics was roughly 1 billion years ago and explains one of the mysterious of evolution, the Cambrian explosion of life. The mystery is what changed at the time of the Cambrian explosion of life, to explain the Cambrian explosion of life.
The reason that there are only three tiny pieces of continental crust for the first 3 billion years of the earth is that plate tectonics started roughly a billion years ago, driven by the solidifying of the core of the plate which causes super high-pressure liquid CH4 to be extruded from the liquid core when it crystallizes.
It has been known for some time that convection motion in the earth does not and cannot physically explain plate tectonics and plate tectonics does not explain mountain building. The lack of a forcing mechanism explains why the theory of plate tectonics took so long to be accepted.
Based on observations (there are roughly 50 independent observations that support the assertion) plate tectonics is driven by liquid CH4 that is extruded from the liquid core of the planet as it solidifies.
That assertion is consistent with the analysis of wave velocity which shows there must be light elements in the core and theoretical analysis for the liquid core that shows CH4 can ‘dissolve’ in the liquid core and would be extrude when a portion of liquid core solidifies.
It is believed the core of the planet started to solidify roughly a billion years ago. At that time there would be a large increase in extruded liquid CH4 which explains why there is a sudden increase in continent crust building at that time. The sudden increase in continental crust building and the increase in water on the planet at the time is the likely explanation for the Cambrian ‘explosion’ of complex life forms.
The continuous release of CH4 up into the mantel and into the biosphere explains why the earth is 70% covered with water even though there is continuous removal of water from the earth’s atmosphere by the solar wind.
Organic metals form in the very, very, high pressure liquid CH4. These organic metals drop at specific pressures.
The forced movement of the super high-pressure liquid CH4 from the liquid core and drop out of the organic metals at specific pressures explains why there is heavy metal concentration in the crust of in some cases a million times more concentrated than the mantel.
The same mechanism explains why there is helium in some natural gas fields and oil fields. The helium is produced from radioactive decay of the concentrated Uranium and Thorium that drops out at specific pressures. The super high pressure CH4 that is moving through the mantel provides a path for the helium gas to move up to higher locations where the natural gas and oil are found.
The same mechanism also explains why the tectonic plate movement has double in speed.
http://www.natureworldnews.com/articles/8831/20140902/tectonic-plates-moving-faster-earth-ages.htm
https://www.newgeology.us/presentation21.html
Plate Tectonics: too weak to build mountains
“plate tectonics does not explain mountain building”
Observational evidence says otherwise. Mt. building occurs if one continental plate pushes into another, as currently occurs with India pushing Asia to produce the Himalayan Mts or Africa into Europe to produce the Alps, OR oceanic crust subducting under Asia and melting to produce volcanic arcs, e.g., Japan,
Core extrusion of CH4 is another one of the “could” ideas without direct support (see above). Earth (and other inner planets) likely acquired most of its C as CO2 and most of its H as H20, not CH4. Solar system chemistry as a function of temperature and solar distance at work.
The Rockies are thought to have been formed when the Pacific plate diving under the N. American continent bent back upwards for a time, colliding with the underside of the plate causing bending and folding at that point.
“Mt. building occurs if one continental plate pushes into another … OR oceanic crust subducting….”
OR apparently, as in the Rockies and Great Basin, where tectonic forces are trying to stretch a continent. . Caveat: I’m don’t have any doubt that’s true, but I really don’t understand how it works.
Actually the Rocky Mountains (Laramide Orogeny) and tectonics of Western North America are such an oddity that there is actually still quite a bit of debate on the details of how it happened.
South America and the Andes are the ideal model, with the orogenic belt right at the active tectonic margin, whereas in North America the front of the Rockies are over 1,000 km from the active margin with multiple active volcanics and orogenic belts between the Rockies and the plate margins.
Whatever was subducted under the North American plate is not your typical oceanic crust, but perhaps a mix of oceanic and continental crust in the form of microcontinents. Instead of being subducted at a high angle, the subducted plate is refusing to sink and is instead dragging itself along the bottom of North America, stretching the continent more than uplifting it for the past 30 million years.
No mystery to the Laramide Orogeny. Much of westernmost North American land didn’t exist then. Two oceanic plates (not the Pacific Plate) subducted under the North American plate, just as is happening now under the Cascades and Andes.
http://images.fineartamerica.com/images-medium-large/1-north-america-late-cretaceous-period-gary-hincks.jpg
‘dond’
Your comment is either ignorant and/or you are a troll.
As you or your pseudonym made a similar incorrect comment, as if you were really interested in the topic as opposed to a troll, who is a type a Zombie.
A Zombie repeats incorrect statements to push an agenda.
Plate tectonics cannot explain the South American and North American mountain ranges.
The ocean slab passes under the continental crust. There is no colliding continental crust
As stated below the protracted collision between India and Asia is one of the paradoxes of plate tectonics. The movement should stop when the continent plates collide.
Map of late Late Cretaceous North America.
Why do you believe movement must stop when continental plates collide?
As long as the underlying currents are still driving the plates, they are going to continue to try and move, and rock will bend under that pressure.
And it’s only the few upper kilometers of crust that it is brittle and hard. Below 10 km the crust is better described as plastic.
“three small pieces”?
https://upload.wikimedia.org/wikipedia/commons/0/0a/Cratons_IT.svg
William Astley:
It’s the mantle, not the mantel
What are “organic metals” and when they “drop out” where do they “drop out” to? (ignores all the advances in igneous petrology since it began)
Extensive quotes from carefully disguised creationist websites don’t really provide evidence. The links you gave appear to be focused on finding inconsistencies in broadly held scientific theories, listing them in long litanies and not providing alternatives until you are sufficiently anaesthetized to be ready for the punch line (in which god plays a major role).
Following links led me to some of their star conclusions: “humans and dinosaurs co-existed”; “Michelson-Morley experiment did not disprove the existence of the ether” after which I got the hang of their methodologies and gave up. The one on plate tectonics is more erudite than most and doesn’t lead directly to god. It highlights inconsistencies and possible inadequacies in theories of what actually drives plate tectonics. So what? Are we supposed to know everything and have all the answers now? We do science to try and get closer to ultimate truths. And there are many competing theories, so they can’t all be right. It’s even possible that in the case of plate tectonics and what actually drives it, that none of them are right.
Creationists like to present themselves as being persecuted. Perhaps they should be.
They should be laughed out of the room when they try to present the Bible as science. There is no science in the Bible. Both Testaments are prescientific, which is surprising in the case of the New, by which time Greek science was far along.
And indeed they were literally laughed off the witness box during the Dover, PA trial, when the packs of “Intelligent Design” lies were shown to lifted directly from creationist garbage rightly banned from public school science classes. The Bible can and should still be taught in comparative religions classes. It is orders of magnitude superior to the Koran in every way.
My hypothesis is that snowball Earth trapped all heat generated by the Earth’s core ( a true greenhouse effect) and caused a build up of that heat under the ice until finally the heat prevailed and cracked the crust allowing the escaping heat to melt the snowball and create the oceans and plate tectonics. Where do I send my grant request?
Request to be sent to the ” CO2 false greenhouse effect” department.
Miller and Stern have an interesting hypothesis, but they have a huge amount of work ahead of them to prove it.
my two questions: 1) did the separation of South America from Antarctica allow the circumpolar current, surrounding the continent with a wall of cold water, preventing warm tropical water from circulating to the south polar regions lead to glaciation of Antarctica?
2) did the filling of the Isthmus of Panama alter ocean currents, leading to glaciation in the northern hemisphere? I recall that there is a moderate difference in sea level between the Pacific and Atlantic in this region. What the effect of building a sea level canal, perhaps in Nicaragua, allowing free flow?
“What the effect of building a sea level canal, perhaps in Nicaragua, allowing free flow?”
Probably about the same as digging a sea level canal at Suez == virtually none. Keep in mind that the Central American land bridge between North and South America has only been in place for a few million years and for much of that time the bridge was quite possibly intermittent — present when there was lots of polar ice, but flooded at sea high-stands.
Not enough water and too shallow to make any difference.
“Not enough water and too shallow to make any difference.”
Dead on if we’re talking about currents and climate. However even a narrow channel only a few fathoms deep can probably support a lot of marine fauna and floral interchange.between two bodies of water/
Don,
Yup. That could happen. It did with Suez:
https://en.wikipedia.org/wiki/Lessepsian_migration
But, yes. The glaciation of Antarctica coincides with the formation of deep sea channels between it and South America and Australia, creating the Southern Ocean. And the onset of NH ice sheets is associated with the closure of the Interamerican Seaway.
How could shifting plates change the earth’s axis of rotation? Much less change it enough to influence climate?
Mark, try this experiment for yourself.
Preparations: Obtain a keyring, then attach numerous keys (identical or of varying weights and sizes, have fun with it).
Procedure: Spin them around on your finger.
Observations: Note the spread of the keys about the axis of rotation and the integrated centripetal pull on your finger, among other things.
Now, tape two of the keys together. Repeat your observations.
Hope this helps!
Perhaps your size relationship may be a bit off.
Assumption of a consistent, stable atmosphere implied?
This is a ridiculous hypothesis. It took some time for large continents to develop but plate tectonics started at least 3.0 billion years ago.
The last two snowball earth periods were caused by super-continents Rhodinia and Pannotia being over centered over the south pole. (not located correctly in this history of super-continents).
There was a lot more water on early Earth than today.
Both water has been entrained in hydrated crustal minerals and photosynthesis decomposed water to oxygen and hydrogen to greatly alter the atmosphere with 21% O2 today.
Also the surface atmospheric pressure was likely higher on early Earth as high levels of CO2 made the atmosphere denser. A diminished atmospheric pressure greatly cooled the surface.
http://ircamera.as.arizona.edu/NatSci102/NatSci102/images/atmosgases.jpg
It would be less ridiculous if they said that the first and worst Snowball Earth episode was caused by the start up of plate tectonics. Dunno why they don’t mention the Huronian glaciation (2.4 to 2.1 Ga) of the Paleoproterozoic Era or the shorter Pongolan of the Mesoarchean Era.
http://web.gps.caltech.edu/~jkirschvink/pdfs/snowball.pdf
The Pongola glaciation occurred around 2.9 Ga. The first supercontinent Vaalbara broke up during this era about 2.8 Ma.
Make that 2.8 Ga, not Ma.
I think any attempt at knowing what the Earth’s land structure was > 1.5 Ga is hand-wavium.
The continuous melting and re-melting of subducting crustal plates and unconformities of strata in the geologic record have erased so so much.
Once it is erased by subduction and unconformities, it really does mean that.
Erase = It’s gone, unless someone builds an working time machine to go back 2 Ga and take a peek.
Joel,
All we have to go on is the continental crust which does survive from then. Granted, not much.
Instead of theorizing that it was the “start” of plate tectonics, perhaps instead it was just more of a transition time.
My theory would be pre-snowball earth there were larger and fewer plates. These would be more easily locked in place for longer durations in time. The plates being locked in place caused snowball earth, with the subsequent unlocking and breaking apart of the plates into smaller plates bringing the snowball earth period to an end.
A wild theory I know, but I have just as much evidence for my theory as they do…none.
Here is a good review of the evidence for Archaean and Early Proterozoic plate tectonics:
https://www.geosociety.org/gsatoday/archive/16/7/pdf/i1052-5173-16-7-4.pdf
Nick Eyles would have put this nonsense to bed. His magisterial review of glaciation includes the well established Huronian glaciation of 2.4 Bya, of which Stern et al appear entirely ignorant. However Eyles did note the odd gap in glaciation between 2.2 Bya and the Cryogenian, just 750 Mya. Maybe tectonics were active in the early earth including the Huronian, then paused during the “boring billion” years from the Huronian till the Cryogenian?
BTW Eyles showed that the earth was never frozen solid during global glaciations such that the ice sheets were frozen to the underlying rock; instead the massive up to 1km deep pebbly deposits show that the ice sheets were water-lubricated at their bases and remained mobile, not frozen solid.
Eyles N. Glacio-epochs and the supercontinent cycle after∼ 3.0 Ga: tectonic boundary conditions for glaciation. Palaeogeography, Palaeoclimatology, Palaeoecology. 2008 Feb 13;258(1-2):89-129.
Abstract
Tectonic influences on long-term climate change are of considerable current interest and debate. This paper reviews the relationship between multi-million year periods of glaciation (glacio-epochs) over the last 3 Ga of Earth history and phases of supercontinent breakup and assembly. A preferred but not exclusive relationship is evident between glacio-epochs and their mostly glacially influenced marine record, with rifting. The earliest known glaciation (mid Archean ∼ 2.9 Ga) is recorded in the marine Mozaan Group of South Africa deposited along the passive margin of the Kapvaal Craton then part of the early continent Ur. The Paleoproterozoic glacio-epoch, exemplified by the Huronian Supergroup of Ontario, Canada (∼ 2.4 Ga) and strata in northern Europe and the U.S., is associated with rifting of Kenorland. A long Paleo-Mesoproterozoic non-glacial interval (c. 2.3 Ga to 750 Ma?) coincides with continental collisions and high standing Himalayan-scale orogenic belts marking the suturing of supercontinents Nena-Columbia and Rodinia. A near absence of glacial deposits other than at 1.8 Ga, may reflect lack of preservation. The extensive and prolonged Neoproterozoic glacio-epoch records either diachronous glaciations or discrete pulses of cooling between ∼ 750 and ∼ 580 Ma, and is overwhelmingly recorded by substantial thicknesses (1 km+) of glacially influenced marine strata stored in rift basins. These formed on the mid to low latitude (< 30°) oceanic margins of western (Panthalassa: Australia, China, Western North America) and eastern (Iapetus: Northwest Europe) margins of a disintegrating Rodinia. The youngest glacially influenced deposits formed about 580 Ma along the compressional Cadomian Belt exterior to Rodinia (Gaskiers Formation) possibly correlative with the classic passive margin Marinoan deposits of South Australia.
A short-lived (1 to 15 Ma?) Early Paleozoic ice sheet about 440 Ma grew over highlands on the polar North Africa margin of Gondwana possibly likely triggered by uplift at high paleolatitudes as large terranes (e.g., Meguma, Avalonia) rifted away from North Africa. Incised valleys, coarse glacial fills and thick (1 km +) ‘postglacial’ shales suggest a continuing tectonic influence. Devonian cooling across the Frasnian-Famennian boundary (c. 376 Ma) is recorded by local ice covers in Brazil and Bolivia and is linked to elevated topography and enhanced erosion of continental crust. The Late Paleozoic glacio-epoch (∼ 350 and 250 Ma) coincides with a high paleolatitude positioning of Gondwana and the growth of high standing topography when Gondwana collided with Laurasia to create Pangea. Breakup after 180 Ma moved landmasses into higher northerly latitudes and was the backdrop to global cooling of the Cenozoic glacio-epoch that commenced after the Paleocene–Eocene Thermal Maximum (< 55 Ma). Earliest Antarctic ice at ∼ 40 Ma most likely nucleated on the high shoulders of the Transantarctic Rift coeval with opening of Drake Passage, and coincides with the earliest ice rafting in the Arctic Basin at 43 Ma, followed by another pulse at 34 Ma. Accelerated glacierization in both hemispheres occurred at ∼ 14 Ma during the middle Miocene Transition but Milankovitch-forced continental-scale ice sheets did not nucleate in the northern hemisphere until after 3.5 Ma on uplifted borderlands along North Atlantic passive margins.
A preferred association of the deposits of Proterozoic and Phanerozoic glacio-epochs with rift basins reflects either a causal link between rift-related uplift and regional cooling, or simply enhanced preservation of glacial sediments. Glacial deposits are poorly preserved in areas of compressional tectonics.
So 1360 W/m^2 at the equator isn’t enough to prevent freezing? 10th that amount works t9 day.
With Antarctic like levels of albedo? There would be rather fewer incident watts at the equator.
The sun was weaker in both spectrum and luminosity 4 to 2 Ga. So the Earth was more prone to freeze overs. What kept it from permanent freeze over was a likely higher surface pressure/density. CO2 ( molar mass: 44) is both a GHG and its molar mass is higher than O2 (32), N2 (28), and H2O (34), Ar (40). Thus early Earth likely had a denser lower atmosphere, but as O2 replaced CO2 starting ~2.7 Ga, the atmosphere became less dense, resulting a cooling effect, that was steadily counteracted by an increasing luminosity sun. As well the sea levels fell as water was locked into crustal minerals and subducting slabs, and decompostion by photosynthesis. There were likely periods where geology and biology got ahead of slow increasing solar output, thus a snowball earth. Vast volcanism (traps releasing CO2) and increasing solar output once again unlocked the freezer.
Molar mass of water is 18, but I catch your drift.
But IMO CO2 had nothing to do with escape from Snowball Earth episodes.
Ouch on my part. 16 of course. Brain EtOH intoxication. I think I need another beer and just quit typing.
But hey, maybe it was H2O2. The Peroxide-oxoic!
Some great comments here from real geologists. It would be good also to hear from Bill Illis.
Please see above:
Bill Illis May 8, 2018 at 9:30 am
The only way that climate can change is through mankind’s use of fossil fuels. So before mankind started to make use of fossil fuels there was no climate change what so ever.
Humans will never be able to equal, let alone exceed, the catastrophic climate change wreaked by cyanobacteria in the Great Oxygen Catastrophe.
During that oxygenation catastrophe, recent micro-palaeontology has shown that a social grouping of bacteria formed, calling themselves “350.org”, insisting that the new bacteriogenic pollutant oxygen be stopped from exceeding 350 ppm. In the event it reached 200,000 ppm – and it wasn’t so bad – except of course for our anoxic bacterial proto-environmentalists.
The anaerobes were able to adapt and overcome by hiding out in anoxic environments.
Yes the Earth’s climate was veritable Garden of Eden before 1750 AD. Until we started burning coal and other fossil fuels.
Witness all those Biblical Old Testament stories of peaceful, placid weather, mankind at peace and love with each other, and regular rainfalls, and never a drought or flood.
Thank the Climate Gods for saving Switzerland from the Little Ice Age! The Rhone glacier, AD 1900:
http://wiki.bildungsserver.de/klimawandel/upload/thumb/Rhonegletscher_1900.jpeg/520px-Rhonegletscher_1900.jpeg
The breakthrough proof that plate tectonics is driven by liquid CH4 that is extruded from the liquid core of the planet is the anomalous fact that mid-ocean seismic activity increased starting in 1996 by on average 200% until 2015 at which time it abruptly dropped.
The standard tectonic model cannot explain a sudden worldwide increase in seismic activity and a synchronized drop mid-ocean seismic activity as the geological heating mechanisms are regional not world-wide.
The liquid CH4 mechanism’s force is alway available as that mechanism get it force to drive tectonic plate movement from the force that compresses the liquid core of the planet. When the core crystallizes that force is immediately available and the newly released CH4 immediately presses on the pressurized path to force more liquid CH4 to the surface.
What is required to explain the 200% increase in mid-ocean seismic activity, is mechanism that changes the rate of crystallization of the core of the planet.
The following is observational proof that liquid CH4 is continually being extruded from the liquid core of the planet as it crystallizes.
https://www.yahoo.com/news/500-champagne-methane-seeps-discovered-114400702.html
http://www.sciencemag.org/news/2014/08/numerous-methane-leaks-found-atlantic-sea-floor
See figure in this paper that shows the sudden increase in mid-ocean seismic activity. As the paper note the increase in mid-ocean seismic activity also correlates with recent global warming.
https://www.omicsonline.org/open-access/have-global-temperatures-reached-a-tipping-point-2573-458X-1000149.pdf
The claim that plate tectonic didn’t exist before the Neoproterozoic is simply preposterous. There are plenty of evidences of subduction-related volcanism and arc-back arc tectonic before the continent-continent collision during the Grenville Orogen and the assembly of the supercontinent Rhodinia at ca. 1 Ga. The subduction zone on the Laurentian margin prior the final collision can be traced back in time as far as 1.6 Ga. Modern-style Orogens (e.g., Himalaya-type) have been described in the Paleoproterozoic (1.8 Ga.) with the trans-China or trans-Hudson Orogens. These are also back up by a plentiful of Paleomagnetic studies. Active plate tectonic was likely operating in the Archean around 3.2 Ga.with evidences of paired-metamorphic belts which are usually a pretty convincing signature of active margin. The absence of blue schist, eclogite and ophiolite are absolutely no proof of the absence of plate tectonic in the Archean but are rather due to a somewhat different rheology of the Lithosphere because of a higher geothermal gradient.
In other words, this study is garbage.
” … and computer models suggest that the Earth didn’t cool to temperatures required for plate tectonic activity until then. …”
—-
Oh good grief, what a total load of speculative illogical claptrap … with computer models™.
The problem is that subductive process eats the alleged evidence of the subductive process.
Who was it recently (in a post) who included a quote warning to gather evidence BEFORE you theorise, not the other way around?
Well in precambrian geodynamics the theorised process ‘dog’, ate the geological homework.
Hence back to pointless GIGO based assertions about a geohistory digi-reality … again … speculations … all the way down.
Turn off the useless computer and get a drill core rig and do some 4D ‘truthing’ of the upper 10 km of crust that is actually still observable, and just bearly accessible (at exorbitant $$$ costs), which is still but a tiny residual fraction, of what has allegedly once digi-‘existed’ … well, in theory.
So I wonder, why do people always demand theoretical ‘explanations’, when the required material to provided one is technologically and/or economically inaccessible, and more problematically, physically doesn’t even exist anymore—if it ever did?
Why can’t they just say the honest truth, that, “we don’t know”.
No, that woud be honest. Nope, we HAVE to project untestable fictions, over the unknown or unknowable instead, because it seems the human ego and psychology can’t permit the unknown and unknowable to exist, even though it still does, and always will—we must instead pretend we ‘know’.
There is an insistence, a psychological need, to pretend away the honesty of not knowing. Why can’t we just be content with unknowables being facts, too?
Why model the unknowable, just to pointlessly project the untestable?
So we can assert a comforting fiction of expertise, it seems.
But computer models change everything! 🌈 🍰
No, outcrops and drill cores actually change everything. Anything else is useless fictional time-wasting by people who can’t deal honestly with the FACT of the unknown, and the total lack of actual expertise, sans outcrop, drill-core access to the knowable.
WX,
Here’s the deal. Clearly, the Hadean Earth didn’t have plate tectonics, since for most of it, the “crust” (not formed yet) was more or less molten.
So the question becomes, when in the Archean Eon or Paleoproterozoic Era did tectonics start up? There is not a lot of rock from that time left with which to test hypotheses. But what evidence is available suggests that sometime before 3 Ga tectonics hadn’t yet begun, but sometime around then or shortly thereafter, they had. That’s all we have to go on.
No, what is being INTERPRETED as plate tectonic crustal and mantle process began after 3gya.
You are much to quick and way too confident to accept glib assertions Felix. That’s not a good trait in a field or lab geologist trying to figure out how things really ocurred from proceses and rock assemblages that no longer form, in exponrntially decreasing older crustal blocks and their increadingly altered and reworked units.
IMO we can’t say whether plate tectonics began at 3.2 Ga or 2.8 Ga, but I favor an earlier date, in the Archean, for which evidence is mounting:
Archean Subduction: Fact or Fiction?
https://www.annualreviews.org/doi/10.1146/annurev-earth-042711-105255
Subduction drives plate tectonics and builds continental crust, and as such is one of the most important processes for shaping the present-day Earth. Here we review both theory and observations for the viability and style of Archean subduction. High Archean mantle temperature gave low mantle viscosity and affected plate strength and plate buoyancy. This resulted in slower or intermittent subduction, either of which resulted in Earth cooling profiles that fit available data. Some geological observations are interpreted as subduction related, including an “arc” signature in various igneous rocks (suggesting burial of surface material to depths of 50–100 km), structural thrust belts and dipping seismic reflectors, and high-pressure–low-temperature and low-pressure–high-temperature paired metamorphic belts. Combined geodynamical and geochemical evidence suggests that subduction operated in the Archean, although not, as often assumed, as shallow flat subduction. Instead, subduction was more episodic in nature, with more intermittent plate motion than in the Phanerozoic.
Greetings Gentlemen:
If I may interject a half-pfennig’s worth of thought, I did an undergrad thesis on PreCambrian tectonics, which, in the early 1970’s, was somewhat limited in the number of references I was able to find. If my feeble memory serves, there were some papers by a gentleman named Piper (and probably a long list of co-authors) which were syntheses of (what were called at the time) APW curves. The “APW” meant ‘apparent polar wander’. Using today’s geographic (rotational) pole position as the reference point, they reconstructed the apparent ‘wander’ of the African, Laurentian, and Amazonia cratons, with dates going back as far as 3.2 and 3.3 Ga. There were other authors who did separate reconstructions, and in some cases, the curves had remarkable similarities, and also had discrepancies (easy to understand why; same data, different boundary conditions … ).
It has always struck me that Venus and Earth have a number of similarities, and yes, a number of differences, geophysically, but Earth has an active tectonic system, and Venus (apparently) does not. Now, I am NOT an authority on the subject of Astrogeophysics, but I cannot help but wonder if the fact that Venus has a VERY slow rotation, and Earth (comparatively) has a very fast rotation, if there is something in the resultant centripetal acceleration that induced the tectonics we see today. I have not found a way to test the idea, but I keep thinking about it. The whole idea only makes sense if the early Earth was largely molten; once a thick, hard crust forms, it would be difficult to induce a system as we see today.
We also know that the Earth rotated faster in the Cambrian (about mid-Cambrian, the year had about 425 days), so extrapolating back (and applying some exponential decay as we move forward in time), it should be sensible that in Early PreCambrian time, the Earth was rotating quite fast.
So, as I said, some idle speculation, and thoughts that have permeated my grey matter for a number of decades now.
I welcome your thoughts, comments, and critiques, with all my regards to you and yours,
Vlad
Vlad,
A day lasted about 10.5 current-hours 3.0 Ga. Not precise, but close enough for government work.
Australian zircon shows that crust must have cooled at least in places by 4.4 Ga:
http://www.cbc.ca/news/technology/zircon-crystal-is-oldest-piece-of-earth-ever-found-1.2550895
Oldest continental crust had apparently formed by 3.8 Ga in Greenland, although controversial evidence from Canada says as long ago as 4.3 Ga, the dating technique of which has been questioned.
https://www.newscientist.com/article/dn14818-discovery-of-worlds-oldest-rocks-challenged-
So IMO there’s no reason why plate tectonics couldn’t have begun in some manner before 3.0 Ga. The Greenland evidence suggests possibly even as early as 3.8 Ga, since the rocks of that age are ophiolite, a chunk of oceanic crust embedded within a continent.
Current thinking about the formation of the planets holds that the gas giants formed near to the sun where most of the gas making up those planets was concentrated. The rocky planets formed farther out and migrated inward while the gas planets migrated outward. At the time of global freezing our planet would have been located much farther from the sun; no need to invoke tectonics.
We live on a thin skim wrapped around a ball of hot porridge. When you pour cold milk on it or drop things onto or in it, the skim can move around, like India, Saudi Arabia, Australia, South America, the Levant, etc. I am here to utterly shatter any notions and myths that are based “beneath the firmament.” A broader and much more scientifically robust system must therefore, without any hesitation or reservation whatsoever, include the initiators being “extra-terrestrial”, non-Kardasian, heavenly bodies in origin, such as comets, asteroids, planetesimals, planetoids and the like. The outer cooling of this ball of porridge could easily occur with Mighty Sol Invictus blowing on it, even with Sol’s hot, quarky, bosonic breath. Yes, there is most definitely visible evidence from space of continent splitting strikes even with half or portions of one crater on one continent and the other half on another continent or plate. Just put the pieces together and you see exactly where the impacts took place, mountain ranges, rivers, basins, plains and all. Highly impressive and highly logical.
Anyone need only look at a lava lake to see what I imagine the planetary surface looked like after the earth formed.
My opinion is that the water had to be present within the planetary matrix in order to allow crustal cracking and plate tectonics to form. It’s one thing to have a very thin layer of solid rock being driven by upwelling thermal movement, but when you’re talking hundreds to thousands of feet of material, something needs to lubricate that process. Water fits that role, and water had to have been present from the start. It would be unlikely for sufficient quantity to seep through surface rocks to depth that would allow plate tectonics to begin.
Slushball v. Iceball Earth:
http://blogs.ei.columbia.edu/2018/05/04/snowball-earth-frozen-solid/
Slushball isn’t all that much worse than the coldest phases of the Phanerozoic Eon Icehouses, ie Ordovician-Silurian, Carboniferous-Permian (both Paleozoic Era) and our present Paleogene-Neogene (Cenozic Era) glaciation.
http://blogs.ei.columbia.edu/wp-content/uploads/2018/05/slushball-earth-637×397.png
The Mesozic Era was generally too warm, equable and tectonically unfavorable for a full on glaciation.
Neither carbon dioxide nor plate tectonics has the power to change the climate. The evidence for the former simply isn’t there, and the evidence for the latter is countered by an inconvenient truth: the existence of the greatest “snowball Earth” in geologic history, the Huronian glaciation some 300 million years long, about 2.3 billion years ago, at a time when there was supposedly no plate tectonics. Well, the fact is that at that time, plate tectonics was in a “hot subduction” phase, which began about 3000 million years ago and gave way to an intermediate phase about 1700 million years ago. The present phase of cold subduction began about 770 million years ago, about the time of the series of 2 (perhaps 3) more recent “snowball Earths.” These events were most probably caused by proliferations of photosynthetic life forms that produced an abundance of oxygen, which, in turn, produced an abundance of ozone, which thickened the ozone shield, which then shut out a lot of Sun’s hottest, ultraviolet radiation, thereby cooling Earth’s surface and promoting the “snowball” conditions.