This really helps me grasp how old the earth is. Continents moving about the speed my fingernails grow and that they have broken apart and come together many times. It’s amazing
One of your best, this one. I hope your future plans include the writing of books. You'd be good at it. There's nothing that holds the attention quite so well as enthusiasm on the printed page.
Whaast? I didn't know about the first five at all! Why didn't anyone talk about them before? Seems you're the first here, Rachel! Thank you for my weekly dose of geology 😅🌺
thank you for teaching me ! this was considerably different than what I was taught in school some 50~60 years ago and makes alot more sense ! thank you for that ! the extension events now make alot more sense and understanding why 65Mil years ago the dinos were already on their way out, makes more sense now ! and the asteroid was just the final straw so to speak....... thank you so much !
Thank you for the video about supercontinents. This is something that has sparked my interest. I was researching the black diamond called the enigma that Richard Heart unethically purchased through Sotheby's. Back when Rodinia was a supercontinent there may have been a meteor shower and it's why black diamonds are typically found in Brazil and Central Africa which made up Rodinia. Rodinia is Russian meaning motherland. I thought that was pretty cool 😎. Then your channel show up on my homepage, even cooler 😎. Peace and Ahev
THANK YOU! I've wondered about how continental drift affects life for a few years, and you summed it up very nicely. What hypotheses do we have for WHY the continents drift the way they do? Why wasn't continental drift occurring for the first billion years or whatever of Earth's history? What drives them together, and then apart again? Does the mantle have a 250 million year cycle of sloshing back and forth somehow? I look forward to future vids!
Thanks for another great video. I'm from the West of UK in the area called Avalon (Avalonia) but at the moment I am in Agadir Morocco, just where the CAMP break up was located. It's really old rock here. Think it's called the West African Craton (WAC) There are fossils in the garden here and this is where the Atlas mountains drop down to the sea. Looks like the mountains just got cut up with a big knife! Thanks for the wonderful channel.
Correction! The WAC is further south from here in Agadir. This area is an Orogeny. The High Atlas are here and the WAC starts down in the Low Atlas. There's a place called Tafraoute surrounded by very beautiful mountains. That's on the WAC! The Sahara is scary big when you look south!!.)
Excellent video. I have some questions though... 1. Rather than a super continent, or any continent; could the first land on Earth have been more like islands (bits of continent forming here, there, and thither), which then coalesced into the first actual continent(s)? 2. I see a lot of rain "events" these days and the flooding that inevitably follows; could that be weathering and erosion that will lead to increased carbon burial? (Hopefully not burying too many people in the process) 3. The most hopeful thing I've learned, from you, about mass extinction events; is that even the worst ones don't seem to wipe out life completely. So, I do you think that means the formation of a future super continent, and any mass extinction will behave the same way? (I sure hope something survives.)
If subduction works the way you mentioned, all the planet’s have been eating itself and Earth is cooling down. So with these numbers, it can’t be that way.
is it not the case that each mass extinction has resulted in a reduction of body-plan diversity? it has certainly reduced the total number of phyla on the Earth. so is it actually accurate to say that these breakups led to "diversification" if each event actually reduced the variability (and diversity) of macroscopic animals?
Ur is a play on words with one of the oldest cities in history Ur in Mesopotamia (according to the Bible also Abraham's birthplace), and the German syllable Ur meaning "origin" as in "Urkontinent" (paleocontinent) or "Urmensch" (early hominid). So I would pronounce it like "oor".
Not floating? Continental crust is kept up by the fact that its density is less than that of the mantle, isn't it? The stresses involved are large enough to deform rock, whether by faulting of lithosphere or plastic deformation of asthenosphere, so it seems to me as though it should count as floating even though the material involved is solid.
Absolutely! I just think most people assume I mean floating on water or on magma or some type of liquid when I use the word 'floating' so I didn't want to give that misperception through using that word, but yes, you are absolutely right that it is kind of floating, just on a solid instead of liquid! ;D
That looks to be a most uncomfortable chair you have in the background. I do hope that those with the means will contribute to a better one. If not , perhaps a roadside collection🤗
I got the impression that you're saying the movement of the continents caused extinction events, with hardly any mention of vulcanism. The Siberian Traps caused massive extinctions ~250 Ma, the Indian Traps wiped out life ~35 Ma, and the Atlantic Rift between NA, Europe and Africa caused a lot of extinctions. I'm sure the continental masses and their location on the globe had an effect on life. But I think vulcanism affected it more.
The water isn't lost forever, it goes back into the surface cycle eventually because the water brought down in oceanic plates induces meling underneath subduction zones that leads to magma formation and rise and ultimately volcanism, which releases the water vapor back into the atmosphere, where it'll rain out and go back into the surface water cycle. :)
@@GEOGIRL Yes, but over time the Earth's mantle has cooled reducing the expulsion of water and there are various chemical reactions at extreme pressures locking hydroxyls into minerals. This has caused the Earth's oceans to drop over time. You can see that is how the "super continents" get bigger ( more land above sea level) over time. It is though Earth was completely covered in water soon after formation.
Isn't the unclarity of the Pannotia situation i little bit like what we have today? Since there is a continental connection spanning the Bering straight, all major continents except Australia are connected. This should satisfy the criteria for being a supercontinent, but most geologists seem to think that it isn't. (And wasn't that also part of why the whole "previously disjointed continents form up..." addition?) I would prefer that there would be a tangible criterion, such as one that could be at least indicated in the geological record, rather than than this "yeah, but..." situation. But it is what it is, I guess.
If the breakup of supercontinents like Pangea leads to species diversification via isolation, does the formation of supercontinents lead to a loss of diversification due to previously-isolated species competing for the same niches? Or does the associated climate change disrupt existing niches anyway?
Before North and South America became connected, SA was dominated by an entire suite of marsupials including large predators, large herbivores, and the whole lot of smaller marsupials filling mammalian roles. Afterwards, all but a few of the smallest were replaced by placental mammals from the north. The only marsupial that made it to NA and survived is the opossum, a generalist that will eat almost anything and produces a lot of young rapidly. Of, course, after they migrated they diversified, so it's a toss up whether there were more mammal species in SA before or after, but they were certainly different ones.
I'm glad you pointed out that they aren't all confirmed. As for the definition of supercontinent, it's complicated. Anyway. Rodina is know. To have existed as well as Nuna/Columbia. The others are pure conjecture. Although there likely were others. We can actually reconstruct paleogeography. Maybe you should do something on that 😊 I like how you addressed the Archean. Well done! Ur is complete BS. I don't know why it keeps floating around...pun intended.
"Ur" should be pronounced "ooh-r". It comes from a German prefix meaning "original". If you hear English speakers pronouncing it like "your", they're probably misreading it because they're so used to the texting abbreviation "ur" for "your"/"you're".
if all of the land mass forms 1 continent, why doesn't the earth wobble and flip over? That would happen if the mass of the land is not evenly spread out
Another boring about definition if or not a super-continent. The importance of big landmass is * they are so big so have a fully locked inside area without rain * there mein position like equator or pole, to trigger another world wide climate. Over this definition discussion we forget over the important impacts of size and position.
sounds like so much double talk- it is this and that and does this and that- just look- it's doing everything you think and doesn't do- it's all there! Silly Christians. But they are silly though lol But make your mind up lol
Thank you for another great video! I’ve now been a channel member for two years!!! And I’ve always been impressed by your knowledge, skill and passion for the amazing subject of geosciences, Dr. Geo Girl! One thing that I’ve been curious about concerning Gondwana is its existence as a coherent landmass both before its fusing with Euramerica to form Pangea AND after Pangea’s breakup. That makes me wonder if the rocks in orogenic provinces are much more broken and weaker than in the more stable cratons. So in general when continental rifting begins, it’s much more likely to occur in areas like the Central Pangean Mountains than in continental shield areas. (And maybe that’s why the Midcontinent Rift System failed to break apart North America?) Do you know more about this? Thank you again for your wonderful and talented work!!!
That is a great question! I don't know for sure, but I have always assumed exactly like you said that the non-craton parts of the continents are always the weak zones that are liable to future rifting and breaking apart, but I will have to look further into this to really understand the mechanisms behind why :D Thanks so so so much for your amazing support as a channel member (and virtual friend
It seems like it based on the evidence we have. And in fact, the future supercontinent I hinted at in the end of the video is thought to potential cause the mass extinction of mammals in large part due to this desertification of land effect!
Howdy Rachel, thanks for another interesting topic. Back in my academic days I only remember Pangea and Gondwana being discussed, and plate tectonics only then being more globally accepted. And in my career expanding back to Columbia/Nena. But I suspect Vaalbará might have been larger than we might be able to prove because of continental mass being re-incorporated into the mantle. Look forward to seeing the model of the future Supercontinent. Who will take over after mammals? Birds?
Love this. I have a Ph.D in geology, but my topic didn’t cover a lot of earth’s history. I appreciate that you don’t glaze over details that a wonk like me requires. :-)
There is a new paper out, that proposes that the fresh water cycle a.k.a. weathering started earlier and might also have accelerated the beginning of life earlier than thought. I'm curious how you think about this and if you would lecture us about that 😃
Dang, I can hardly wait for the video about the next supercontinent! But at least I don't have to wait the whole 200 million years to see it in real life.
Great video! I'm surprised by the map of the future super-continent. I get that Africa is moving North, but will in squeeze between North America and Europe, or continue to crash into Europe closing off the Mediterranean? Also, I thought Australia was moving North, so shouldn't it eventually crash into Asia the way India did? And North America has already crashed into far-eastern Siberia, so won't the Bering sea eventually close up? I would expect that the next super-continent would be made up of Africa, Eurasia, Australia and North America, with East Africa, Antarctica and South America being the remaining smaller continents.
Well there are mulitple potential scenarios of future supercontinent configurations and I will go through the 4 most likely ones in that next video that I mentioned, which will come out in about two weeks! :D Hope you will come back to check it out!
You really deepened my understanding of the supercontinents and the mass extinctions around them. I still don't have knowledge of every detail but I have a better foundation to draw on in my readings. Thaks a bunch!
Fun fact: the Caspian Sea, while considered a "lake" since its landlocked, it's actually the last remnant of the Tethis Sea, as Eurasia closed in around it. It's bottom is oceanic crust, rather than continental crust, like other true lakes
Can you elaborae how weathering of rocks sequesters carbon in the ocean? I thought snowball earth was caused since this weathering released nutrients into the ocean, accelerating the growth of photosynthesizing algee---- Great video overall
It does both! First, silicate weathering (the weathering of silicate rocks which are the most common ones in Earth's crust) induces the transport of CO3 and cations like Ca and Mg to the ocean where they form carbonate rocks like CaCO3 and Ca,MgCO3 (limestone), and this sequester carbon from the atmosphere (because the CO3 originally comes from H2CO3 in acid rain which resulted from the reaction between CO2 and H2O vapor in the atmosphere). And second, continental weathering transports nutrients to the ocean, just as you said, increasing the algal or photosynthetic blooms or activity in the photic zone of the water column, which increases the production of organic carbon (the body mass of the algal or bacterial bloom) and subsequently the burial (sequestration) of that organic carbon in the ocean sediment as the dead bodies of those organisms eventually fall to the sea floor. So, it is somewhat indirect, but a very powerful carbon sequestration mechanism. Hope this helps! ;) If you want to hear a better explanation of this in video format, I recommend this video (specifically, the section on silicate weathering about 11 minutes in): th-cam.com/video/cc4KmzVqU8U/w-d-xo.html
An amazing collection of videos. I wonder if there are descriptions of how the oceanic crust or ocean floor has changed over the millenia? The changes might have significant effects on the ocean, climate and life. For example, the ocean bowl in the atlantic has a resonant frequency near the lunar 12 hr cycle which greatly affects the tide heights up and down the american east coast.
Thanks for making this really informative video!!! Can you please make a video about Vaalbara, Ur, Kenorland, Arctica (?) and Columbia/Nana? I've looked for more information about these first contents but i haven't been able to find much info (as you have mention). Maybe you could discuss the evidence for these continents, and alternative theories? Also, in the past when reading about these early continents, i have assumed that they were created by plate tectonics, but thats really interesting that they formed before plate tectonics started (you video with Steve was super interesting btw! ). One thing im wondering now is why would these first continents form all together instead of all of the lighter continental material raising to the surface through differentiation equally across the early earth? Please make a video about this, it would be super interesting 😀
So you take an entire continent, you move it along on the mantle-lithosphere boundary, you bang it into other continents, and then you have a supercontinent, until it heats up in the middle and breaks up into smaller continental sized fragments again. Then, you so this again and again over the course of the Earth's 4.6 billion year history and-Voila! (Mind blown.)
If there are any metalheads in the comments section I highly recommend "Valbaara" by ERRA. The song is fantastic and has some neat geologic/Mesopotamia references!
It is also possible the massive expenses of desert contributed to bio diversity via isolation. Members of the same species that were seperated by newly expending deserts could have speciated.
Dear Geo Girl. Thank you so much. This video was epic. It's one thing to have these events explained on their own, but having the movement of the continents layered with the extinctions and ice ages and global warming and evolution of life... it all came together beautifully to tell a huge chunk of Earth's story that has, until now, seemed rather fragmented in my mind. It's such a delight to see how all of this comes together. You rock!
Thanks so much for this comment! This makes me so happy! So glad the video really pulled a lot of information together for you, that is one of my favorite things about geology as a field! :D
I would be very interested in a video discussing what (little?) is known about some of the earlier proposed supercontinents, especially in the later Archean and early Proterozoic. My understanding is that the earliest land masses were probably a result of mantle plumes, but that at some point before plate tectonics developed there was a lid tectonic regime and there might have been one or more supercontinents during that phase.
Well, plants and animals did not evolve on land until about 400-300 million years ago. Before that, there were some marine animals but only back to about 600 million years. Rodinia and earlier supercontinents were before land animals and plants were a thing :D So crazy to think about!
Thanks for another great video! Your explanations are always easy to understand and the graphics visually complement what you're saying, making the information easier to assimilate and remember. You have all the hallmarks of a great teacher! 👏👏👍🏻👍🏻😊
Supercontinents remind me of eyeball planets. And they seem to happen when snowball and slushball planets happen. Perhaps such glaciation pushes continents together. And don't forget the equatorial budge. Which would spread continents going over it, and come back together after going over the budge.
Is it possible that when the glaciers melt the pressure at the equator from liquid water and less pressure at the poles (no ice) the faults float differently? Is there correlation between global temperature and continental drift?
I suppose that afer millions of years of species being separated, man has come and made a kind of homoginization of ecosystems by introducing the strogest species in each land mass to the other land masses.
I hadn't thought through the process before: when India met EurAsia and started to push into it, the land was flat at first, then hilly. It took a few thousand (million?) years for the mountains to pile up. Animals could venture back and forth for quite a while before the mountains blocked their travel. That's very interesting. Thanks for sparking a new connection in my old brain.
This really helps me grasp how old the earth is. Continents moving about the speed my fingernails grow and that they have broken apart and come together many times. It’s amazing
That is so true! I never thought about it like that, but actually fingernail growth is probably a bit faster than continent movement haha ;)
Even supercontinents have problematic breakups.
Thanks for another great video! Your star is shining brighter and brighter!
Loved your video!
I recently got down a rabbit hole reading about the supercontinent Rodinia and the Great Discontinuity in the geological record
Godwana is my jam
I swear I could listen to this for hours, amazing work breaking it down!
One of your best, this one. I hope your future plans include the writing of books. You'd be good at it. There's nothing that holds the attention quite so well as enthusiasm on the printed page.
Whaast? I didn't know about the first five at all! Why didn't anyone talk about them before? Seems you're the first here, Rachel! Thank you for my weekly dose of geology 😅🌺
thank you for teaching me ! this was considerably different than what I was taught in school some 50~60 years ago and makes alot more sense ! thank you for that ! the extension events now make alot more sense and understanding why 65Mil years ago the dinos were already on their way out, makes more sense now ! and the asteroid was just the final straw so to speak....... thank you so much !
Absolutely terrific video. Thank you.
Thank you so much!
Thank you for the video about supercontinents. This is something that has sparked my interest. I was researching the black diamond called the enigma that Richard Heart unethically purchased through Sotheby's. Back when Rodinia was a supercontinent there may have been a meteor shower and it's why black diamonds are typically found in Brazil and Central Africa which made up Rodinia. Rodinia is Russian meaning motherland. I thought that was pretty cool 😎. Then your channel show up on my homepage, even cooler 😎.
Peace and Ahev
THANK YOU! I've wondered about how continental drift affects life for a few years, and you summed it up very nicely. What hypotheses do we have for WHY the continents drift the way they do? Why wasn't continental drift occurring for the first billion years or whatever of Earth's history? What drives them together, and then apart again? Does the mantle have a 250 million year cycle of sloshing back and forth somehow? I look forward to future vids!
I was really in search of this video. Thank you
Thanks for another great video. I'm from the West of UK in the area called Avalon (Avalonia) but at the moment I am in Agadir Morocco, just where the CAMP break up was located. It's really old rock here. Think it's called the West African Craton (WAC) There are fossils in the garden here and this is where the Atlas mountains drop down to the sea. Looks like the mountains just got cut up with a big knife! Thanks for the wonderful channel.
Correction! The WAC is further south from here in Agadir. This area is an Orogeny. The High Atlas are here and the WAC starts down in the Low Atlas. There's a place called Tafraoute surrounded by very beautiful mountains. That's on the WAC! The Sahara is scary big when you look south!!.)
I'll look forward to the next one then. Thanks!
Thanks again!
Excellent video.
I have some questions though...
1. Rather than a super continent, or any continent; could the first land on Earth have been more like islands (bits of continent forming here, there, and thither), which then coalesced into the first actual continent(s)?
2. I see a lot of rain "events" these days and the flooding that inevitably follows; could that be weathering and erosion that will lead to increased carbon burial? (Hopefully not burying too many people in the process)
3. The most hopeful thing I've learned, from you, about mass extinction events; is that even the worst ones don't seem to wipe out life completely. So, I do you think that means the formation of a future super continent, and any mass extinction will behave the same way? (I sure hope something survives.)
Yaaaaay! Thank you
If all of the super continents came together at the same time would they form a Justice League?
If subduction works the way you mentioned, all the planet’s have been eating itself and Earth is cooling down. So with these numbers, it can’t be that way.
is it not the case that each mass extinction has resulted in a reduction of body-plan diversity? it has certainly reduced the total number of phyla on the Earth. so is it actually accurate to say that these breakups led to "diversification" if each event actually reduced the variability (and diversity) of macroscopic animals?
Ur is a play on words with one of the oldest cities in history Ur in Mesopotamia (according to the Bible also Abraham's birthplace), and the German syllable Ur meaning "origin" as in "Urkontinent" (paleocontinent) or "Urmensch" (early hominid). So I would pronounce it like "oor".
Thank you!
Not floating? Continental crust is kept up by the fact that its density is less than that of the mantle, isn't it? The stresses involved are large enough to deform rock, whether by faulting of lithosphere or plastic deformation of asthenosphere, so it seems to me as though it should count as floating even though the material involved is solid.
Absolutely! I just think most people assume I mean floating on water or on magma or some type of liquid when I use the word 'floating' so I didn't want to give that misperception through using that word, but yes, you are absolutely right that it is kind of floating, just on a solid instead of liquid! ;D
That looks to be a most uncomfortable chair you have in the background. I do hope that those with the means will contribute to a better one. If not , perhaps a roadside collection🤗
Haha, it is not too bad, but my cat, Hope, absolutely loves it, so it has become her chair anyway ;)
I got the impression that you're saying the movement of the continents caused extinction events, with hardly any mention of vulcanism. The Siberian Traps caused massive extinctions ~250 Ma, the Indian Traps wiped out life ~35 Ma, and the Atlantic Rift between NA, Europe and Africa caused a lot of extinctions. I'm sure the continental masses and their location on the globe had an effect on life. But I think vulcanism affected it more.
i have a carbonaceous meteorite i wanna do isotope oxygen ,can u help for finding where to do it thx ,
So, Rachel, if you had a time-machine which part of Pangea would you love to visit and more importantly which time period would you visit?
1:55 The Alps are another example. They are formed by Africa moving North towards Europe.
What about the dropping of ocean levels over time due to water lost to oceanic "plate" tectonics?
The water isn't lost forever, it goes back into the surface cycle eventually because the water brought down in oceanic plates induces meling underneath subduction zones that leads to magma formation and rise and ultimately volcanism, which releases the water vapor back into the atmosphere, where it'll rain out and go back into the surface water cycle. :)
@@GEOGIRL Yes, but over time the Earth's mantle has cooled reducing the expulsion of water and there are various chemical reactions at extreme pressures locking hydroxyls into minerals. This has caused the Earth's oceans to drop over time. You can see that is how the "super continents" get bigger ( more land above sea level) over time. It is though Earth was completely covered in water soon after formation.
Isn't the unclarity of the Pannotia situation i little bit like what we have today? Since there is a continental connection spanning the Bering straight, all major continents except Australia are connected.
This should satisfy the criteria for being a supercontinent, but most geologists seem to think that it isn't. (And wasn't that also part of why the whole "previously disjointed continents form up..." addition?)
I would prefer that there would be a tangible criterion, such as one that could be at least indicated in the geological record, rather than than this "yeah, but..." situation. But it is what it is, I guess.
Look! Down on the ground! It's a crust--it's a mantle--it's Supercontinent!
If the breakup of supercontinents like Pangea leads to species diversification via isolation, does the formation of supercontinents lead to a loss of diversification due to previously-isolated species competing for the same niches? Or does the associated climate change disrupt existing niches anyway?
Before North and South America became connected, SA was dominated by an entire suite of marsupials including large predators, large herbivores, and the whole lot of smaller marsupials filling mammalian roles. Afterwards, all but a few of the smallest were replaced by placental mammals from the north. The only marsupial that made it to NA and survived is the opossum, a generalist that will eat almost anything and produces a lot of young rapidly. Of, course, after they migrated they diversified, so it's a toss up whether there were more mammal species in SA before or after, but they were certainly different ones.
Can an astronomical impact object (meteorite) puncture through the crust and initiate a new plate boundary?
The three biggest known impacts (Vredefort, Sudbury, Chicxulub) penetrated deep into the mantle but didn't have any effects on plate tectonics.
Case in point: Tuatara.
I'm glad you pointed out that they aren't all confirmed. As for the definition of supercontinent, it's complicated.
Anyway. Rodina is know. To have existed as well as Nuna/Columbia. The others are pure conjecture. Although there likely were others.
We can actually reconstruct paleogeography. Maybe you should do something on that 😊
I like how you addressed the Archean. Well done!
Ur is complete BS. I don't know why it keeps floating around...pun intended.
What about Eurasia?
Reunite Pangea!
Africa, Europe, Asia, India are a lot of continents smushed together, so is that a supercontinent as well then?
"Ur" should be pronounced "ooh-r". It comes from a German prefix meaning "original". If you hear English speakers pronouncing it like "your", they're probably misreading it because they're so used to the texting abbreviation "ur" for "your"/"you're".
Thanks! This is very helpful! :D
if all of the land mass forms 1 continent, why doesn't the earth wobble and flip over? That would happen if the mass of the land is not evenly spread out
Because the weight is negligible compared to the total mass of the Earth.
Another boring about definition if or not a super-continent.
The importance of big landmass is
* they are so big so have a fully locked inside area without rain
* there mein position like equator or pole, to trigger another world wide climate.
Over this definition discussion we forget over the important impacts of size and position.
sounds like so much double talk- it is this and that and does this and that- just look- it's doing everything you think and doesn't do- it's all there! Silly Christians. But they are silly though lol But make your mind up lol
Thank you for another great video! I’ve now been a channel member for two years!!! And I’ve always been impressed by your knowledge, skill and passion for the amazing subject of geosciences, Dr. Geo Girl! One thing that I’ve been curious about concerning Gondwana is its existence as a coherent landmass both before its fusing with Euramerica to form Pangea AND after Pangea’s breakup. That makes me wonder if the rocks in orogenic provinces are much more broken and weaker than in the more stable cratons. So in general when continental rifting begins, it’s much more likely to occur in areas like the Central Pangean Mountains than in continental shield areas. (And maybe that’s why the Midcontinent Rift System failed to break apart North America?) Do you know more about this? Thank you again for your wonderful and talented work!!!
That is a great question! I don't know for sure, but I have always assumed exactly like you said that the non-craton parts of the continents are always the weak zones that are liable to future rifting and breaking apart, but I will have to look further into this to really understand the mechanisms behind why :D
Thanks so so so much for your amazing support as a channel member (and virtual friend
The possible extinction of mammals? What a cliffhanger ending!
I'm against that!
Your videos have become more enjoyable for me as you've gotten more experience making them.
Thank you so much! I continue to try to improve each one :)
Rachel ⛳,
Solid work ⛏️. That was well constructed and super interesting!
👏👏👏👏👏
Thanks so much! I am so glad you enjoyed it :D
@@GEOGIRL You do tons of good works. Like the Steve Keen of geology...
Does desertification (like in the case of Pangaea) predictably occur whenever landmasses become large enough?
It seems like it based on the evidence we have. And in fact, the future supercontinent I hinted at in the end of the video is thought to potential cause the mass extinction of mammals in large part due to this desertification of land effect!
Howdy Rachel, thanks for another interesting topic. Back in my academic days I only remember Pangea and Gondwana being discussed, and plate tectonics only then being more globally accepted. And in my career expanding back to Columbia/Nena. But I suspect Vaalbará might have been larger than we might be able to prove because of continental mass being re-incorporated into the mantle.
Look forward to seeing the model of the future Supercontinent. Who will take over after mammals? Birds?
Thanks, very nice presentation
Wow I didnt know there were several super continents, and Pangea is the most recent one. Thanks for this awesome video
Same here.
Geo Girl is a super TH-camr! Keep these awesome videos coming! ❤🎉😊
Thank you!
As a Kiwi Gondwana for ever.
Love this. I have a Ph.D in geology, but my topic didn’t cover a lot of earth’s history. I appreciate that you don’t glaze over details that a wonk like me requires. :-)
There is a new paper out, that proposes that the fresh water cycle a.k.a. weathering started earlier and might also have accelerated the beginning of life earlier than thought. I'm curious how you think about this and if you would lecture us about that 😃
Your videos were helpful to clear iit jam geology exam, so thank you
Dang, I can hardly wait for the video about the next supercontinent! But at least I don't have to wait the whole 200 million years to see it in real life.
Some dude is going to be lucky enough to marry this woman!
Ur looks like a diving penguin. Such a cool name too, Ur!
Great video! I'm surprised by the map of the future super-continent. I get that Africa is moving North, but will in squeeze between North America and Europe, or continue to crash into Europe closing off the Mediterranean? Also, I thought Australia was moving North, so shouldn't it eventually crash into Asia the way India did? And North America has already crashed into far-eastern Siberia, so won't the Bering sea eventually close up? I would expect that the next super-continent would be made up of Africa, Eurasia, Australia and North America, with East Africa, Antarctica and South America being the remaining smaller continents.
Well there are mulitple potential scenarios of future supercontinent configurations and I will go through the 4 most likely ones in that next video that I mentioned, which will come out in about two weeks! :D Hope you will come back to check it out!
You really deepened my understanding of the supercontinents and the mass extinctions around them. I still don't have knowledge of every detail but I have a better foundation to draw on in my readings. Thaks a bunch!
Fun fact: the Caspian Sea, while considered a "lake" since its landlocked, it's actually the last remnant of the Tethis Sea, as Eurasia closed in around it. It's bottom is oceanic crust, rather than continental crust, like other true lakes
What about the Black and Mediterranean Seas?
Can you elaborae how weathering of rocks sequesters carbon in the ocean? I thought snowball earth was caused since this weathering released nutrients into the ocean, accelerating the growth of photosynthesizing algee---- Great video overall
It does both! First, silicate weathering (the weathering of silicate rocks which are the most common ones in Earth's crust) induces the transport of CO3 and cations like Ca and Mg to the ocean where they form carbonate rocks like CaCO3 and Ca,MgCO3 (limestone), and this sequester carbon from the atmosphere (because the CO3 originally comes from H2CO3 in acid rain which resulted from the reaction between CO2 and H2O vapor in the atmosphere). And second, continental weathering transports nutrients to the ocean, just as you said, increasing the algal or photosynthetic blooms or activity in the photic zone of the water column, which increases the production of organic carbon (the body mass of the algal or bacterial bloom) and subsequently the burial (sequestration) of that organic carbon in the ocean sediment as the dead bodies of those organisms eventually fall to the sea floor. So, it is somewhat indirect, but a very powerful carbon sequestration mechanism. Hope this helps! ;) If you want to hear a better explanation of this in video format, I recommend this video (specifically, the section on silicate weathering about 11 minutes in): th-cam.com/video/cc4KmzVqU8U/w-d-xo.html
@GEOGIRL this is great! Thank-you so much!
"the extinction of mammals"
*SAD POGGLE NOISES*
An amazing collection of videos. I wonder if there are descriptions of how the oceanic crust or ocean floor has changed over the millenia? The changes might have significant effects on the ocean, climate and life. For example, the ocean bowl in the atlantic has a resonant frequency near the lunar 12 hr cycle which greatly affects the tide heights up and down the american east coast.
Oooo Rachel, this is worth looking into! Free advice from Mom 😊❤
Thanks for making this really informative video!!! Can you please make a video about Vaalbara, Ur, Kenorland, Arctica (?) and Columbia/Nana? I've looked for more information about these first contents but i haven't been able to find much info (as you have mention). Maybe you could discuss the evidence for these continents, and alternative theories? Also, in the past when reading about these early continents, i have assumed that they were created by plate tectonics, but thats really interesting that they formed before plate tectonics started (you video with Steve was super interesting btw! ). One thing im wondering now is why would these first continents form all together instead of all of the lighter continental material raising to the surface through differentiation equally across the early earth? Please make a video about this, it would be super interesting 😀
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So you take an entire continent, you move it along on the mantle-lithosphere boundary, you bang it into other continents, and then you have a supercontinent, until it heats up in the middle and breaks up into smaller continental sized fragments again. Then, you so this again and again over the course of the Earth's 4.6 billion year history and-Voila!
(Mind blown.)
All this talk of subduction & orogenous zones is making a bulge in my magma chamber.
If there are any metalheads in the comments section I highly recommend "Valbaara" by ERRA. The song is fantastic and has some neat geologic/Mesopotamia references!
Pangea is my favorite 'cause i know what it is!
14:10 OMG! I'm amazed to know that the tropical place where I live was once located at the South Pole.
It is also possible the massive expenses of desert contributed to bio diversity via isolation. Members of the same species that were seperated by newly expending deserts could have speciated.
Thanks , I spent the whole video thinking will she talk about the future. Well now I have even more reason to wait on the next episode!
Dear Geo Girl. Thank you so much. This video was epic. It's one thing to have these events explained on their own, but having the movement of the continents layered with the extinctions and ice ages and global warming and evolution of life... it all came together beautifully to tell a huge chunk of Earth's story that has, until now, seemed rather fragmented in my mind. It's such a delight to see how all of this comes together. You rock!
Thanks so much for this comment! This makes me so happy! So glad the video really pulled a lot of information together for you, that is one of my favorite things about geology as a field! :D
Always brightening up my day 🌻
That was all very interesting. Thank you.
I would be very interested in a video discussing what (little?) is known about some of the earlier proposed supercontinents, especially in the later Archean and early Proterozoic. My understanding is that the earliest land masses were probably a result of mantle plumes, but that at some point before plate tectonics developed there was a lid tectonic regime and there might have been one or more supercontinents during that phase.
There was a time before plate tectonics? I'm going to have to watch your earlier videos to find out about that!
Sorry your text is overlapping important figures. Unable to see pics.
Thanks for letting me know! I'll try to fix that in future videos ;)
Interesting that, of all the displayed supercontinents, only Pangea and, to a lesser extent, Gondwana had plants and animals living on them.🤔
Well, plants and animals did not evolve on land until about 400-300 million years ago. Before that, there were some marine animals but only back to about 600 million years. Rodinia and earlier supercontinents were before land animals and plants were a thing :D So crazy to think about!
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What a fascinating topic!
Thanks for another great video! Your explanations are always easy to understand and the graphics visually complement what you're saying, making the information easier to assimilate and remember. You have all the hallmarks of a great teacher! 👏👏👍🏻👍🏻😊
Supercontinents remind me of eyeball planets. And they seem to happen when snowball and slushball planets happen. Perhaps such glaciation pushes continents together. And don't forget the equatorial budge. Which would spread continents going over it, and come back together after going over the budge.
Meh. At 57% of the world's land area, and 85% the size of Gondwana, Afro-Eurasia is more than enough to be the sixth supercontinent to me.
The pointy finger saga IS OVER!
So are your videos part of your teaching curriculum, Rachael?
BS about 5 super-continents, there was only one.
everyone is forgetting the continent of "Longoland". how do i know you asked. trust me bruh.
Is it possible that when the glaciers melt the pressure at the equator from liquid water and less pressure at the poles (no ice) the faults float differently?
Is there correlation between global temperature and continental drift?
Why is Afro-Eurasia not considered a supercontinent?
I suppose that afer millions of years of species being separated, man has come and made a kind of homoginization of ecosystems by introducing the strogest species in each land mass to the other land masses.
When did sedimentary layers begin? The earth was solid lava at first?
Thank you Dr Phillips.
I hadn't thought through the process before: when India met EurAsia and started to push into it, the land was flat at first, then hilly. It took a few thousand (million?) years for the mountains to pile up. Animals could venture back and forth for quite a while before the mountains blocked their travel. That's very interesting. Thanks for sparking a new connection in my old brain.
Yes! Millions of years! Glad you enjoyed that bit :)
I thought we had more joined land now than at the end of the Cretaceous, North and South America and India to Asia?
Nice but it would so much better with animation of the globe.
thanks Dr geo girl
nice vid
Really?
Very Informative, GEO-Goddess!!!