Snowball Earth or Slushball Earths? 3 times Earth was covered in ice | GEO GIRL

[@gilafunk]

I have, for reasons I can't readily explain, become obsessed with geology and, specifically, the 'deep time' of earth's geological evolution. One of the many stunners in learning about the earth's history has been the Snow/Slush Ball phenomenon. I think, for me, it highlights how profoundly "alive" this planet is with all the mind boggling changes it's gone through since its earliest moments. As a lay person, I appreciate how you make geology accessible for someone like me while still being scientifically rigorous. Your videos are becoming a regular source for my thirst for all things geologic! Great work!

[@ShadowCoyoteDKM]

Looked all over trying to find out how the first snowball earth ended, and finally found it here. Everyone talks about it, no one covers how it ended. But you. Thank you.

[@GEOGIRL]

Thanks so much for this comment! I am so happy you found what you were looking for from me ;D

[@tedetienne7639]

This is a great, super informative video! I’m very glad to see that iridium deposition from meteorites is being used to date geologic time frames! Did you know that this was the suggestion from astrophysicist Luis Alvarez to his son, geologist Walter Alvarez? They first assumed that the sudden change in life at the K-Pg Boundary meant that this layer represented a long gap in time. Testing the iridium in that layer would give an estimate for that gap. Of course, when the iridium concentrations came back several orders of magnitude more than they were expecting, the Alvarez’s needed to come up with another source for all that iridium. Thus, the impact extinction hypothesis was born! (Another fun fact: Do you know why the Earth’s crust is depleted of iridium? The element bonds easily with iron - “siderophile” - and so, during the iron catastrophe, a lot of iridium was leached down into the core. So cool to know!)

[@GEOGIRL]

So cool! I knew a little bit about the first fun fact, the father son duo and the impact hypothesis for KPg boundary, but not to that level of detail, and I had no idea about why Ir was not abundant on Earth, but now that you say that it makes so much sense, thanks for sharing these facts! I think I learn more from you all in my audience than you do from me hahaha ;)

[@tomg3290]

Men have not planted a flag on the Sun..beware of letting space norms become earth norms . We are cold and dense , most of the universe is snot...shuttle doors weild themselves shut over time . The energy's are not equal.

[@johnsonhunglo1993]

Will this close down all of the schools?

[@jansegal6687]

'one of the coolest periods of earth', i saw what you did there. and again, thank you geo

[@GEOGIRL]

HAHAHA I didn't even notice that pun! Great catch, I wish I meant to do that lol :D

[@punditgi]

Earth was a Slushie? Holy Tokedo, Batman! Geo Girl is always full of nice surprises! 🎉😊

[@oliverweeweepie3132]

What a good summary of lots of interrelated processes! I a big fan of these short informative videos.

[@GEOGIRL]

Thanks Oliver! Glad you enjoy them :)

[@jeffreygosselin7576]

I am waiting for the “Chocolate Earth.” Sorry ‘bout that! 😬

[@thalespescarini]

Wow, what a GREAT video and channel! Tons of information put in a very accessible way, congratulations and keep this awesome work!!!

[@GEOGIRL]

Thanks so much! I am so glad you enjoyed the video and like the channel! ;D

[@darrenhay5672]

Thanks Geo Girl, your vids are awesome! The only complaint I have is that I didn't find them earlier. Love your work!

[@GEOGIRL]

Wow, thank you so much! I am so glad you are enjoying my videos ;D

[@joeybutcher-kd5pn]

Well done! You make this information so pleasant and digestible. I can absorb it all most efficiently with your lovely presentation . Thank you

[@Grumpyoldman037]

Very good video! I had a little trouble following it at points (humbling experience). As usual, I will continue watching your videos. I love them.

[@GEOGIRL]

Thank you so much! I am so glad you are enjoying my videos even though you may not understand every point or concept. Trust me, I am right there with you. Before making most videos, I don't know much at all! I tend to learn everything about the topic for a few weeks by reading up on it and then I just give it all away in the video and forget about it 3 weeks later hahaha! I literally have to re-watch my own videos sometimes to remember things I forgot I learned 😂 But I have such a blast learning all these things and I am so glad others enjoy hearing them from me, it really makes it worth my time :)

[@Grumpyoldman037]

@@GEOGIRL I am still digging through my many crates of books looking for my first textbook on plate tectonics However, I did fing my second textbook, "Physical Geography: Earth Systems" by John J. Hidore, published 1974, and bought new for the class. Tells you just how old of a coot I am... But I have been interested ever since. Still don't know one rock from another, but maybe I will learn from you, eh?

[@barbaradurfee645]

@@Grumpyoldman037 the same book is on our shelf at home 😊

[@deepdrag8131]

Great presentation!

[@dirk-hennerlankenau4899]

This is an excellent contribution! - Thank you very, very much - very usefull ! - As of the figures and graphical contributions it would be very nice to have a reference source directly in each topic-slide. I checked out some of the links you are giving below - that is very usefull, thanks. But, for example I missed in the case of a snowball-earth link - where the credit is given to "University of Tokyo" - the precise scientific literature reference. It would be so nice, if you could put into the videos or below some of the key-scientific, peer reviewed journal articles as well. It would be highly appreciated ! Cheers, Dirk

[@SamtheIrishexan]

"This time on earth is earths time" I love that. Shows you think alot about our place in the universe. Some people believe life only exists in one place at a time, or rather 1 place in time.

[@linjie1213]

always want to know more about Snowball Earth since I first heard of it in SciShow channel. .. but as a nonprofessional I am not gonna read the whole textbook for it. Thx so much for making this video!

[@CatharticCurios]

That's the first time I learned about the jump to multi cell life and omg it's so cool! Ty for sharing!

[@sdluedtke7803]

Wonderful and extremely educational video. Thank you greatly, SDL. 🌟

[@GEOGIRL]

Thank you so much! So glad you enjoyed it ;)

[@rogertulk8607]

Rachel, I remember being told 65 years ago in school that lake Erie is still subsiding after the last glaciation. I considered studying geology for a while but ended up with a degree in psychology.

[@seanconway918]

Great video! I am a big GOE fan too. I always referred to the first glaciation as the Huronian glaciation - certainly easier to pronounce. Lastly, I vaguely recall that deuterium was another piece of evidence for these glaciations because deuterium water has lower freezing temperature it would be more abundant, but I am not sure what trace it left. Any help?

[@GEOGIRL]

Yes, I know that dueterium isotope evidence is used for reconstructions of past climate, etc. but I am not so sure exactly how. I will have to look into it and maybe make a hydrogen isotopes video ;D

[@mateuszjedut2406]

Wasn't the pongola glaciation the first glaciation on Earth?

[@ChrisSlowens]

Awesome content! KZbin's algorithm is finally recommending good videos again! I feel like it's been broken for so long. Curious... I may be mistaken, but it seems like glaciation events became less extreme over time. Is that a function of things like more biological inputs or increased sun activity? Thanks for the cool video!

[@GEOGIRL]

That's a great question! I think it is a combination of a lot of things. For example, biology was undergoing major evolutionary advances and radiations during the Precambrian when all of the snowball Earths were happening, so Earth had to balance all of it's biogeochemical cycles back to equilibrium because of the new compounds life wsa creating like molecular oxygen, ozone, etc. Another reason (not for why changes were more drastic then, but maybe a reason why they seem more drastic then) is we have to remember the Precambrian was billions of years. The first snowball earth and the others were over a billion years apart. It may seem like everything after the Precambrian has been 'less severe' but it may be because not enough time has passed to make another big swing and re-balance necessary (it's only been about half a billion years since the end of the Precambrian and the end of the last snowball earth, so we may just be a bit early). Anyway, these are just my initial thoughts, but this is a very interesting topic, so I will look into it and make a future video on the reasons the scientific community cites because now I am very curious! ;D Thanks for sparking this conversation!

[@ChrisSlowens]

@@GEOGIRL thank you for your response! I didn't even think about the vast period of time between the snowball earth events. Look forward to your future videos on the topic!!

[@oker59]

Hey Geo Girl - well, I finally got around to watching this. I must say, I'll just go straight into talking about Snowball Earth implications for life - multi-cellular life. Well, the Slushball Earth idea is that life must not have gone completely extinct. Well, I was going to argue that life could have relied on deep ocean vents; but the point is photosynthetic life would have gone extinct. And, unless photosynthetic life arose again. So, I guess that proves to me that it was probably more Slushball Earth than Snowball Earth!

[@sydhenderson6753]

That's why I never bought Snowball Earth. She mentions a couple of other possibilities, but if you're saying photosynthesis survived due to thin ice, you pretty much have to allow for open water.

[@burkhardstackelberg1203]

Smowball Earth - one of the coolest events im Earth's history - I'd say, pun intended 😂

[@JasonKale]

The 2 things I found super cool about this vid is space dust can me measured in glaciers thats wild and that the singular cell life started to form multi cellular ;ife after the snow ball Earth. As if the DNA was trying to protect itself in any manner it could.

[@stevepax2809]

In college I thought geology was a nearly finished science. Boy was I wrong.

[@GEOGIRL]

I thought so before I got into it as well! I just assumed we had mapped all the rocks on earth and answered all the questions.... little did I know that was not at all true lol!

[@ManicMercurianAstrology]

I have a question , at around 11.5 minutes in the info says we know the globe was covered in ice because there was ice at what was then the equator. How do we know where the equator was 700+ million years ago since not only the tectonic plates are moving, but the poles themselves are moving as well?

[@stevenbaumann8692]

Paleomagnetic tells us where the continents were. Yes. The ocean crust gets recycled. When you have what's called a mafic dike swarm (usually associated with LIPs, which are a talk for another time) in the continental crust, it too will record paleolatitude like the ocean crust will. Around the time of the Neoproterozoic glaciation was a supercontinent called Rodinia. As long as those igneous magic dikes haven't undergone much metamorphism, you can get a reliable latitude. So if a 1.1 billion year old dike cross cuts a known glacial deposit of similar age, and we get a paleo latitude of 30°N we can say that glacial deposit formed at 30°N. I hope that made sense to you.

[@cleon_teunissen]

The phrasing 'what was then the equator' does not work properly to convey what is going on. First, we have to distinguish between geometric poles and magnetic poles. The magnetic poles are (at geological timescale) volatile, but for the question at hand the (orientation of the) magnetic poles is not relevant. The term 'geometric pole' refers to the Earth *rotation* . Compared to geological timescale the Earth's rotation is incomparably fast. We have that the tectonic plates are being moved around by convection cells that span the Earth's mantle. The point is: that motion pattern does not affect the Earth's rotation. The direction of Earth rotation does not change with respect to the *bulk* of the Earth. We have that relative to the *bulk* of the Earth the location of the equator remains the same. Plate tectonics may move a plate towards the Equator, or away from it. So: to reconstruct that at some point even the Equator was covered with ice: if a particular tectonic plate has moved so as to bring it over the Equator, and the geologic record shows that at the time the continent on that tectonic place was covered in ice, then it follows that (that part of) the Equator was covered in ice.

[@ziggle314]

Great information and exposition. The use of the extra-terrestrial origins of high iridium levels to help understand time frames is really interesting. I will be investigating further 😁

[@onesunghero]

Life probably started over from hydrothermal vents during that time.

[@kevinrussell1144]

How about the theory that life, once started, has NEVER gone extinct, and that Snowball earth is a theory, but hardly FACT that every geologist and planetologist bows down to?? Skepticism, even against covid vaccines, doesn't sound like heresy to me.

[@nelsongonzalez1702]

Great video. Excellent information. I'll see it more than once. A tip: Only if you can, try to change or improve the sound of the mic. Sometimes it gets a bit saturated and this increases with the acoustics of the room. Love the channel!!!

[@GEOGIRL]

Yes, I have noticed that as well. I think it is because my heater is really loud, but I am definitely working on that! Thanks for the input :) Also, thanks so much for the support and encouragement. So glad you enjoy the videos!

[@captaincodpiece3263]

“Snowball earth was the coolest period…”, is that a pun?

[@JoesFirewoodVideos]

GEO GIRL GEO GIRL I ❤️ GEO GIRL 26 minutes of watch time. Great video, keep up the awesome content

[@GEOGIRL]

Thanks so much for the support! I am so glad you liked this one, it was one of my favorites to make, I love these kinds of topics :)

[@pizzafrenzyman]

9:18 positive feedback = snowballing effect. How did you miss the obvious pun?

[@GEOGIRL]

Omg that is so brilliant I can't believe I missed that LOL!

[@RM-yw6xe]

I trust you over PBS Eons

[@Julian_Wang-pai]

Iridium spikes are mind-blowing; relating to a specific event and wonderfully time constrained - plus the size of the peak is a measure of accumulation, as such the period of glaciation. Wow!

[@BubblewrapHighway]

Great work! I'm not a geologist but I'm thinking about it.

[@GEOGIRL]

Yes! Go for it :D

[@nickbuffa1814]

I love Geo Girl

[@isejanus2714]

Very informed and informative. For those who haven't read Nick Lane I think it might be helpful to point out that complex life did not evolve from bacteria,, that eucaryotic life is necessary for things like us to exist. I have no idea how to make that accessible to laymen like myself. I was reading Oxygen when it finally dawned on me and made sense, but time limitations of KZbin and your audience attention span might make a thorough exposition impossible despite your audience's interest and good will.

[@GEOGIRL]

Yes! I love that book :D It's funny two of the books in my top ten favorite book list are both called oxygen haha, but they are so different. Nick Lane comes at it from a more biological perspective, whereas Don Canfield comes at it from a paleoceanographic perspective, which I also love!

[@isejanus2714]

@@GEOGIRL I will start with Canfield as soon as I put down Will and Ariel Durant, not geology but history. Keep up the great work you are creating cintent to be proud of.

[@petefluffy7420]

I have heard of snowballs, and even think I know what they are. But I am confused about slush balls. Where I come from slush is wet/muddy ground, watery mud or muddy water. Is that what you mean by slush ? Or is it partly melted snow/partly frozen water ? Thanks

[@Beachbiker05]

Are these glaciation events associated with the Great Discontinuties found in the Grand Canyon, Wyoming, and other places around the planet?

[@pritsahu7]

Once again... Superb madam.... We are waiting for more videos..... But plzz we want some minerology videos from you🙏🙏🙏🙏🙏🙏

[@GEOGIRL]

Thanks Prit Sahu! I know, I have mineralogy on my to do list, but I am sorry, it's probably going to be a few more months until I get to that topic just because I really can only make videos that pertain to what I am teaching during the school year. But over the summer I will have a lot more time for mineralogy videos! ;)

[@genier7829]

What caused the increased mid ocean spreading, and what evidence is there? (with respect to the carbonate deposit formation) Thanks for another great video, I really learn a lot of new things, and remember stuff I knew decades ago as a Geology student.

[@lestatsgames7426]

Please don’t be embarrassed about how you pronounce words. Listening very carefully several times, I’ve determined in my extremely unprofessional criticism that you pronounced the word “words” just fine and did so the exact same way most other Americans pronounce the word “words.” Born in the remote southeastern US in an area with reception for one TV station and one radio station, we were not exposed to anyone who spoke differently than we did. (As the commentator writing about this, I choose to ignore the fact we could see a movie for 25 cents on Saturdays.). It was only in 1965 or 66, cable TV invaded our HUGE town of 6000 people (the largest town in about 100 miles). We watched the soap opera hit TV show DARK SHADOWS in total awe. On our screens, we heard some regular folks, vampires, werewolves, witches, ghosts, and other “nasties” pronounce the word “word” as in “oh my word” kind of like we did - using two syllables. word - as in “were erd” Say were erd close enough together to almost sound like one syllable. However, while the show takes place north of Boston, they spoke without a New England accent. Moral of the story is vampires, werewolves, witches and ghosts’s greatest fears are cultural appropriation because that turns into cancel culture like vampires turning into bats. No one used a New England accent. Angelique was allowed her island accent though. When shows like Dark Shadows get cancelled, the werewolves, vampires, witches, and ghosts are forced to move across America and find other work. When you get old and a bit senile like me, you too can make long comments far off the topic in the video. And if you have an urgent need to criticize my comment, Go ahead. By tomorrow, I I may not even remember writing this.

[@DeanHelton-ki7ku]

I wish scientists could come up with easier to pronounce names for things. Of course I mangle easy words at times. :). Also the pig tails are very cute. You definitely qualify as a little sister I wish I had.

[@roderickr]

Excellent channel! Well done! Thanks!

[@GEOGIRL]

Aw thanks so much, I am so glad you enjoy it!

[@eliinthewolverinestate6729]

Some say earth being and eyeball planet at those times made it rotate on a different axis and flip back in forth. Breaking up the super continents.

[@bernardofigueroa5137]

first of all: I looove your videos. Thank you! I have a question: You mention Franklin Large igneous province (and others), but the largest ones (I think) are basalts, which (I believe, I'm not geologist) are unlikely to expel material up to the stratosphere (not explosive, but efusive eruptions). So, How do you explain that? Is there evidence of (sufficient) explosive volcanic activity to cause the cooling?

[@kevinrussell1144]

Good question. The rocks, as you say, seem to be mostly flood basalts and NOT explosive. So if you want to relate cooling to this long series of igneous events, you have to rely on the sulfur compounds emitted and the weathering that followed to create carbon sinks. The one thing that strikes me in all of this is how many action-reaction pairs are working to moderate conditions on earth.

[@CaptainMir]

Good luck with your channel

[@GEOGIRL]

Thanks so much, I hope you enjoy this video! :)

[@zachjones6944]

Why the Iridium content in the "space dust" be constant?

[@nomdeguerre7265]

The evidenced for global glaciation was always rather...scattered. The fact that life survived, especially eucaryotic life, strongly argues against global, unbroken glaciation. Hell of a way to end the 'boring billion' though, right? ;)

[@hemrajshivran5323]

Thank you so very much .. very informative

[@GEOGIRL]

You're welcome! I am so glad you found it helpful :)

[@peterdore2572]

Greeeat content. thank you :D

[@GEOGIRL]

Thank you so much! ;D

[@stephenelberfeld8175]

It still doesn't explain the iridium rich Holyoke, MA, Triassic/Jurassic clathopteris zone, or why it is possible to pan for iridium in Maine, but not Vermont.

[@thatbeme]

It is a shame you don't know that Europa is too far away to be warm during Earth's freeze. Fantasize about something else. ❤️ You. 🙂

[@GEOGIRL]

Actually, Europa isn't heated by the sun, it's heated by tidal heating (gravitational pull from Jupiter), so it's possible early in the solar system's history, while Jupiter was still migrating around and as the jovian moons were accreting with heat dissipating from accretion and gravitational compression, that Europa was much warmer than it is today. But I agree, it's likely it was still an icy covered world, it's just that we don't know for sure and are still working on understanding the Galilean moon histories ;)

[@TheAppalachianEsq]

These videos are very enjoyable!

[@GEOGIRL]

Thanks! So glad you enjoy them ;D

[@fullyawakened]

I don't see any good reason to split hairs on snowball earth/slushball earth. the slush is there because of the snow, in tiny amounts comparatively. would you try to rename a field as a forest because there's a few bushes growing on it?

[@sydhenderson6753]

Slushball allows for patches of open water. Snowball assumes there is ice everywhere. The distinction matters when you're asking why photosynthesis survived.

[@glenecollins]

I really don’t like the chances of there having been life on the surface of any of the moons in our solar system. If the gas giants were moving around in the solar system enough that the moons would have had sufficient insolation that the surface was above the melting point of water the inner planets would almost certainly have been thrown out of the solar system.(except in the very early solar system when there could have been a lot more planets and earth etc were the ones that got lucky). Barring movement of the gas giants the sun as you mentioned was dimmer in the past and that only leaves impacts and greenhouse effects from super thick atmospheres. There is a limit to the pressure life as we know it can handle in a gas environment so super thick atmosphere doesn’t seem like a great solution and impacts would also boil the oceans etc and would have relatively short effects unless there was more of them. Edit: when the sun goes into it’s end phases there may be enough heat reaching the gas giants to melt the oceans so they may briefly have habitable surfaces before the solar wind stripped off all the volatiles.

[@KerriEverlasting]

Carbon isotopes video next

[@sdsa007]

Woman, I'm trying to keep cool while putting two and two together.. So... I would say Astrums 'Winter is coming' video (very awesome smooth Scottish voice narration) which is not marked with 'climate change' warning ..theorizes that snowball earths or ice-ages can be caused by the space-dust, which causes the 7% less insolation and is coincident with iridium deposits, and a theory of a Milankovitch cycle that involves inclination of the orbit above a solar plane in a planar area covered in dust. What do you think of that? This is in opposition to the general theory that astronomical cycles only cause oscillations of a pre-existing ice-age brought on by tectonic activity. So I am intrigued by a possible 4th Milankovitch cycle and the astronomical history of space-dust in general... and the emergence of Kordylewski dust clouds at the Lagrange points..... is such a theory of inclination a simpler explanation (Occams razor) than the 'perfect storm' on Earth? Heck, it might even explain life on Earth through slushball panspermia! More importantly, is it true or false!? As many videos and NASA only mention 3 Milankovitch cycles, not a 4th. And yet, Astrum's video was not marked with a climate change warning.

[@madenglishman3417]

The 7% less insolation (at that time, compared to today) is exactly that; the Sun was putting out 7% less - and specifically not (as you conjecture) the same insolation as today with space dust reducing it by 7%. The Sun, as a typical Main Sequence star slowly increases its insolation over time.

[@sdsa007]

@@madenglishman3417 interesting 7% less solar output... lets combine that with a space-dust scenerio (with or without inclination or orbital effects)... is there evidence that, in solar system formation, that heavy space-dust plus 7% less solar ouput initially causes snowballs for rocky planets that have gone through planetary smash-up mergers?

[@rommelfcc]

8:40 So a volcano about the size as Yellowstone will be needed to throw earth back into a snowball earth? 🤔

[@GEOGIRL]

That's a great question! First, the type of volcanism that likely led to these snowball earth events (and other climate change events in earth history) are much larger than just one volcano or one eruption. This kind of volcanism took place over a volcanic field with many individual vents/eruptions, occurring on and off for potentially millions of years! So, no one eruption of a yellowstone type volcano would not cause global climate chnage, only local or regional change. Additionally, it would be much more difficult to throw Earth into a snowball state on modern Earth compared to ~2.5-0.5 billion yr old Earth. The reason is becuase the sun's intensity has increased since then, and free oxygen concentrations in the ocean/atmosphere have stabilized on modern Earth. The instability of oxygen concentrations and the evolution and spread of photosynthesizing organisms in the ocean and plants on land created major change, which wouldn't occur today because the life on Earth today (photosynthesizing life and respiring life; aka: oxygen producers and consumers) balance out the oxygen and carbon cycles, preventing super rapid or drastic change. Of course, now on Earth, we have humans throwing the carbon, and thus oxygen, cycle out of balance a bit and this can cause a major warming event, but nothing equivalent to the intensity of snowball earth (aka: the earth will not completely melt or completely freeze due to this climate change, the worst that will happen is a mass extinction, which would get rid of the problem, in this case humans, and bring Earth back to stabilized conditions). Anyway, that was a long way of saying it depends on the intensity, surface area, and duration of the volcanism ;)

[@rommelfcc]

@@GEOGIRL ok maybe 3 - 5 Yellowstone's? 🤔 or maybe the the next big meteorite impact... Would be enough, to set off more volcanoes? I suppose at that point volcanoes would be the last thing on our minds... Hmm or maybe about 20 - 40 normal sized volcanoes eruptions within months of each other?

[@delamr1]

Oh 1.2 BILLION years ago

[@lethaleefox6017]

The increasing intensity of solar output due to the conversion of hydrogen to helium that might allow more compaction and increasing density and that might increase pressure to fuse more hydrogen?

[@johnbaker1256]

Teengirl crush " I'm in love with a slushball"

[@chrisgriffiths2533]

So Geo, Are You saying the Huge Amount of Water on Earth was Present Pre 2.5 Billion Years ago ?. Do We Know the Time there was No Water ?. Also Cell Experiments Today can Not Claim to be Cells of 1 Billion Years ago. Therefore it is Near Impossible to Prove What Cells Were or Did 1 Billion Years ago. Great Stuff though, Very Interesting Topic.

[@GEOGIRL]

Yep, we know roughly when water would have had to be present in large amounts because of dating of rocks from billions of years ago that could've only formed in presence of water, plus everything in geologic history passed that point geological, chemically, physically, and biologically on Earth points to there having been water very early on Earth. We also know when Earth was very hot during it's accretion that all the hydrated materials that make it up were releasing water vapor due to outgassing through abundant volcanoes at the time and this water vapor was caught in the early atmosphere until temperatures dropped to below its boiling point between around ~4 billion years ago and allowed the water vapor to condense to form the oceans. Bombardment by water containing comets and asteroids continued from 4.5-4 ish billion years ago as well which also contributed to the large amount of water on Earth from 4 billion years onward. As for cells, we know those were around by at least 3.5 billion years ago because of clear cellular fossils (microbial mats), which cannot form abiotically and are widespread at that time. One must only assume from that that the origin of life had to have been before life was widespread and then we calculate how far back that should've been based on their cellular development by 3.5 billion years ago. This is where we start to get into assumptions and that is where I completely agree it is hard to say what really happened based on assumptions. However, I will say that everything that happened geologically in earth's history from about 2.5 billion years ago to today is pretty well mapped out and backed up by corroborating stories from rocks around the globe! ;) Hope that makes a bit more sense.

[@lexzbuddy]

The moons of jupiter and saturn are too cold. I don't think people understand how far away they are from the sun.

[@GEOGIRL]

Yes, but they are tidally heated instead of heated mainly by the sun like Earth is :)

[@eoachan9304]

It is unlikely that earth will become a "snowball" until the sun goes through its red giant phase and then becomes a white dwarf :) For now the sun is growing 10% hotter every billion years, so unless our distant descendants manage the sun to stop it, earth either becomes a superheated dessert or vapour, while Europa will indeed thaw during the red giant phase of the sun.

[@nyoodmono4681]

The reason for these snowball earth events is again plate tectonics. Continents could not form yet because the Magma was too hot, they tried though and when they did they allowed ice shields to grow that caused a runaway effect due to albedo. Why in such an extend? Because the sun was way weaker then. The faint sun paradox happened because there was no continents usally, there was a shallow ocean around the globe which was able to be because there was no continents. (Snow can not accumulate on the open seas)

[@GEOGIRL]

I am not sure where you read this about continents not having formed yet, but continents had actually been around for many millions of years before the first snowball earth event. They began forming in the Hadean (~2 billion years before the first snowball earth event) and were completely developed by the end of the Archean, which is then when the GOE occurred and the first snowball earth event set in. The sun was weaker, yes, and I mention that, but the continents were there. the ocean covered more of the Earth because continents hadn't fully developed or accreted onto each other to make large landmasses yet, but they were there ;) If you think about it too, the first event never could've happened without continental margins because that's where cyanobacterial mats grew which caused the initial O2 increase which led to the first snowball earth cooling trend, which was then exacerbated by positive feebacks like ice cover and sun weakness.

[@nyoodmono4681]

@@GEOGIRL From what i know the continets had trouble forming, kept colapsing like egg shell, because the inner flow was too hot/ active. My theory is that when they managed to form, especialy around the poles, this would cause the runaway albedo effect. Maybe i am wrong and there are other huge factors like astronomicals that we do not know yet. It is just that the faint sun paradox to me underlines how important the continents are. The whole 'boring billion' seemed to be so stable temperature wise, neither the increasing solar output, nore the constant decline in CO2 did change anything.

[@kevinrussell1144]

@@GEOGIRL What is your source for stating the sun was "weaker" earlier in earth history. Intuitively, that seems wrong.

[@paulohagan3309]

@@kevinrussell1144 As the sun ages.like many stars it begins to burn more and more brightly until it either supernovas or becomes a Red Giant - as in the case of the sun. Suggest you look up the 'faint young sun paradox' on Wikipedia which will link to further info on that.

[@kevinrussell1144]

@@paulohagan3309 Are brightness and heat necessarily linked?

[@jari2018]

One could talk about how the current earth are covered in slimeballs that belives life is about power and make money and just destoy the earth we are living on

[@nigelwoodley3656]

ARE YOU SHELDON COOPERS TWIN SISTER,,??? HAVE A NICE DAY..

[@GEOGIRL]

Hahaha I'm not sure how to take that, but no, I am unfortunately not his sister ;)

[@kokopelli314]

FF companies love ice ages!

[@cavetroll666]

❄️

[@cluke1620]

LoL you said snowball Earth was a cool period. 😂 I get it. Oops somebody are appointed that out. On another note as many environmental scientists doing an archeology of pointed out human beings are a product of an ice age due to the environmental forces that created and the evolutionary response we had to them.

[@GEOGIRL]

Cool! Love all these comments, I am learning as much from you as you (hopefully) are from me! haha

[@Kraflyn]

"going to be going"? :D

[@delamr1]

How did mammels survive thi

[@stevenbaumann8692]

They didn't exist.

[@michaelkaiser4674]

me likie

[@tomg3290]

I was taught in the mid 80s, that if earth was frozen over..life would end . On land an in the water, maybe ocean bottom microbes ,might survive...so when did things change , what fact ,got in the way.im missing something important , I suspect.

[@paulohagan3309]

I was taught the same thing in the 70s. I think at that time, it was not appreciated how tenacious microbial organisms can be or how 'life finds a way'. Since then, we've learnt how many of them can live frozen for long periods, find slushy niches to live in and even, as was mentioned, live on the surface of ice. They've even found worms that live in ice though they would not be able to survive a snowball Earth.

[@stevenbaumann8692]

During the Precambrian there was no macrolife to end. However there is the stromatolite problem with snowball earth that ppl, including geologists, just gloss over.

[@tomg3290]

@@stevenbaumann8692 I'm a geologist , but I wasn't there ,to see and measure.. boiling rocks support no life..frozen water cannot su0ort life. It doesn't flow ,to allow chemistry to happen. Total death of all DNA based life , is a major setback to evolution .life requires a continuous duration of non boiling non frozen time's...your proposition is preposterous..my retort was safe an accurate..you need to provide " extraordinary proofs ". Sorry - that's the nature of the game.

[@stevenbaumann8692]

@@tomg3290 I'm a professional geologist and I'm seeing where you're getting at. I agree there was no snowball earth. Stromatolites, well the ones we see in Australia, couldn't have survived a frozen world. They've been around longer than cows, dinosaurs, and even trilobites. They go back to at least 3.5 Ga. There are microbes that can go dormant in ice. Those are resilient. Warm water stromatolites are not. They marched right on through every supposed "snowball earth".

[@DavidSmith-jj7ll]

What's the source of carbonates prior to the Cambrian and multicellular life? A quick googling brought up some harder-core papers than I can reasonably digest on a workday.

[@GEOGIRL]

Well carbonates are not only formed biogenetically. They can form aboitically if water becomes saturated enough with Ca2+ and CO32- ions, which often happens in great proportions evaporite environments like dry playa lakes where evaporation causes an over-saturation of the remaining water in salts that precipitate out as solids, one such 'salt' being calcium carbonate. This CaCO3 precipitation can also occur abiotic in the ocean, typically in shallow, warm environments in the photic zone near a continental margin, but this type of environment is typically where you'd see a lot more biogenic carbonate formation than abiotic. Hope that makes sense, now that you ask that question, it makes me want to make a video about the difference between abiotic and biotic carbonates, I think that would make a great video, thanks for the idea! ;)

[@kevinrussell1144]

@@GEOGIRL I'd guess that most of the Precambrian carbonates were also biologic, but were dominated by algal and protist contributions as well as elements like ooids (oolites) and undifferentiated "micrite". Many of these carbonates have since become dolomites.

[@MichealJudkins]

Pigtails ❤

[@jakeyjakey4018]

so cool, although geogirl looks like a boy in this video😅🙈🤷‍♀️

[@TomTom-rh5gk]

Screechy narration. Hard to understand. .

[@ericlewis9472]

You can say words just fine quit being so hard on yourself 😆

[@markotrieste]

16:20 Boron isotope should increase, but we have an explanation also if it decreases. 😂

[@johnchance7836]

Millions of years down the road? From what I've read we came within 6% of reaching the snowball earth tipping point during the last ice age . . . and the reason that the ice was advancing further after each inter-glacial is because we have central America blocking the equatorial flow of water currents, a continent sitting on the south pole, and resting ice on the sea floor. At the moment, if I recall right, the ice is late in returning. It was supposed to be back about the time when the first civilizations appeared but the most we've seen is the little ice age which roughly matches up with the period between the 14th and 19th century, starting when the Native American burn cycle was disrupted by disease, and ending with the industrial revolution and the beginning of the current global warming period. As I understand it, which isn't perfectly, we are currently riding a climate bicycle. Getting rid of the aerosols stopped the acid rain and helped close the ozone hole, but if we take it too far in the other direction and reduce the human induced global warming too far and we'll start to freeze over again in the northern hemisphere. According to Michigan Tech Rodinia drifted over the south pole about 600 million years ago and was a likely cause of the snowball. We are there again. It's kind of scary. Especially when you think about the direction we are going, and how we currently think about global warming. The disaster could start tipping the other way within our lifetime. . . because we are raising a generation of kids who think that ZERO carbon emissions is a moral goal. They have no shades of grey in their understanding.

[@stevenbaumann8692]

We likely will never have anything like another snowball earth. The sun slowly keeps getting hotter and brighter. Other ice ages are possible, but not global ones. The sun is just too hot and too close now.

[@mspicer3262]

"I swear, my information is good, I just do not say words"... haha, you say lots of words. This is my secret to pronouncing things... break it into pieces that are easy to say, and say each piece individually. Like this: Mak - gan - yen - e. Works for people's names too. I learned about that in a public-speaking class, on the one day I paid attention. It was a short class, but I have a short attention span :)

[@GEOGIRL]

Haha, yea, in academia I read these words much more often than hear them lol. And thanks for the tip, that is useful! ;D

[@peterjodway2543]

SLUSHBALL 4 LYFE!!!! ERRY DAY WE SLUSHBALLIN!!! Looooooooovvvvve ittttttttttttttttt. The Society of Sturtian Stratospheric Slushball Sleuths of Houston Heritage House (SSSSSHHH) is one of the coolest recent discoveries of mine. notactuallyrealbutshouldbe. These graphics help to illustrate these concepts in a better manner than most easily accessible content. TYVM!!! As always... nicely done. I'm saving all of your extraterrestrial life videos because I do believe they are all in the order of 'too good to consume at the moment' and are being placed into the 'watch on you deathbed' list. It's because I think that after I watch them, nothing else will be able to compare well with them... honestly you need to dab at the end of your videos

[@peterjodway2543]

I often think in terms of the slushball... the ice couldn't have ever stayed solid, could it have? If plate tectonics is real and if any of the ice layer was attached to landforms, wouldn't a few centimeters of tectonic shift, combined with the natural growth of glaciers provide enough push-pull to create breaks and crevasses that would allow the trade of atmosphere and a weather system? Gah. so amazing. I'm no expert, so ty for clarifications. any other material to read up on, specifically regarding the ending of this period, would be a real treat!! Are there any geologists leading this charge? Twitter handles?

[@peterjodway2543]

and the moon, what would tides do under this sheet of ice? lol sorry i am done now

[@GEOGIRL]

OMG YESSS ERRY DAY WE SLUSHBALLIN! I love that lol Peter, your comments are making my day so much better! Thank you! I am so glad you have those other videos on your 'to watch' list ;) You are the best!!

[@GEOGIRL]

@@peterjodway2543 I love the way you are thinking Peter! You are right on track, the plate movement & the moons pull on Earth would've made it difficult for the ice to remain intact. The fact that there was a supercontinent at the time made it a bit easier than if the continents were separated like today, but even so the push/pull & tension would've been there. The moon's gravitational affect would've played a role, but probably wouldn't make or break the ice if it were thick. The issue is, in some places on Earth it would've been thin enough that tides cold affect it. So all I can say right now is yes, those would've affected it, and yes, it was definitely slushball not iceball, but I don't study this specifically so I don't know all the details, but fun to think about! :D