How Earth’s Crust Formed & Difference Between Tectonic Plates & Crust | GEO GIRL
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- Опубліковано 12 чер 2024
- This video covers how the outer most layer of Earth, the crust, formed, and the difference between Earth's crust and the lithospheric tectonic plates. Although many people think the tectonic plates are equivalent to continental crust, the lithosphere includes both the upper most part of the mantle and the crust. In fact, tectonic plates don't differentiate between continental and oceanic crust; most tectonic plates include both continental and oceanic crust. Boundaries between continental and oceanic crust that are not plate boundaries are called passive margins. However, many continental and oceanic crust boundaries are also plate boundaries due to the difference in density between plates containing oceanic crust and those containing continental crust. Oceanic plates are more dense and will subduct under continental plates, creating subduction zones. This is why supercontinents, like Pangea, have formed on and off throughout Earth's history. Thanks for watching, I hope you enjoyed! ;D
References:
Evolution of the continental crust (Hawkesworth and Kemp, 2006): doi.org/10.1038/nature05191
The Formation and Evolution of the Continental Crust (Arndt, 2013): pubs.geoscienceworld.org/pers...
Moho vs Mantle-Crust boundary (O'Reilly and Griffin, 2013): doi.org/10.1016/j.tecto.2012....
Earth systems history textbook: amzn.to/3v1Iy0G
GEO GIRL Website: www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, & donate to support the channel if you'd like!)
0:00 Video topic/outline
0:38 Oceanic vs Continental Crust
2:40 How Earth Formed
4:31 How Earth’s Layers Formed
5:32 How Earth’s Crust Formed
6:45 How Earth’s Crust Differentiated
9:59 First Continental Crust
12:58 Atmosphere & Ocean Formation
13:59 Crust vs Tectonic Plates
17:19 How Supercontinents Form
19:14 How Supercontinents Affect Climate & Life
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I've got a 9 year old who is in love with this channel already. Thank you for doing what you do
9 years old! Wow that is awesome to hear, thank you so much! :D
Gosh that was well done Rachel! As a geologist myself I acknowledge that we have our own peculiar language and vocabulary. Often when I attempt to explain something in geological terms I get the “deer in the headlights response”, but you have the remarkable talent of making the complex understandable..and, foremost, fun. You possess a very special gift.
Thank you so much! This comment means so much because I use to be SO bad at explaining things in an understandable way to someone outside my field. I remember my first few attempts at explaining my research to a non-scientist friend which ended up just confusing the friend and so then I'd just go on and on for too long and get more and more confusing lol... After all those embarassing attempts I remember becoming a TA and beginning to think like an educator rather than just a researcher and I made it my mission to learn how to explain my research in a way that could be understood by anyone. I don't know if I am quite there yet, but I do know I get better with every video and this comment keeps me motivated to continue improving this skill, so thank you ;D
Yes, it was a long road for me too. Being a optical mineralogy/petrology TA also advanced my teaching abilities, but looking back I think I can give most of the credit to the US Army. The KISS (Keep It Simple Stupid) factor was indelibly ingrained in my poor (and often very frightened) brain. In the the military you had to make yourself very understandable…or bad things could happen.
@@donaldbrizzolara7720 I use KIS religiously (I dropped the second 'S' while introducing this concept to my kids.)
Wish more people would adopt KISS... some people like to overly complicate things in order to appear smarter... but pride is expensive and much opportunity is lost by poor communication, which can confuse or turn people off who might otherwise be interested and ultimately supportive.
Fast talkers are another favorite of mine. To counteract this... talk alittle slower, pause alittle between your words while they're talking, but keep your focus on what you want to say and it'll force them to shut off the lightspeed jibberjabber and they'll actually listen to you. Talk normally once you have their attention.
My wife's the Teacher, I was special consultant for things practical and technological.
So Prof Sean Carroll is a pretty good teacher and although much of the content of the curriculum is getting revised, it's all much too late to keep up with what is required of the next generation of teaching technicians.
Rachel is setting the kind of high standards needed. Thank you.
If the supernova hypothesis is valid, you would think that the shock wave(s) of the supernova induced a “push” on existing elements causing an accumulation of materials via gravitational forces to form a dense region that eventually became dense enough for the hydrogen and helium to form the sun. My point is that I can think of no reason for the gas “cloud” that formed the solar system to not be homogeneous. So when we speak of the inner rocky planets versus the outer gas giants we really mean that the solar wind from the newly formed sun swept away the gas from the inner solar system but not from the outer solar system. In other words, the “rocky” aspect of the solar system was everywhere, but was only revealed by the solar wind closest to the sun. I’m not an expert, I’m just thinking out loud here…
I remember when the Soviets were trying to drill down to the "Moho". They got a 12km deep hole before they failed.
This was really well-explained. you're my new geology channel
Very enlightening, love that you don't shy from introducing technical terms in an approachable way.
Thank you I really appreciate this comment! I have been around geologists for the better part of my life, so I often forget to define certain terms because they are very familiar to me, so I am happy to hear that I introduced the terms in this video in an approachable way, that makes me feel good :)
@@GEOGIRL You are way too modest. But that is one of things things that makes listening to your videos enjoyable. The content is great, you present it clearly, and you are very easy to listen to.
Massubduction! St. Vincent gots green eyes like Rachel.
First of all, I just discovered your videos. I love your narrative style. It both reinforces knowledge and teaches new knowledge. It is also a pleasure for me that it has Turkish subtitles. Thanks.
Thank you! So glad you like my videos :D
@@GEOGIRL I am a Geography student. Although you are an expert in the field of geology, I would like to listen to the videos with the content of "meteorology" with your narration. I would appreciate it if you would think about it one day (I don't know how much it fits in the field of geology). I wish you success in your business.
Nick Zentner and Geo Girl 🙌
Not far from my home, there’s ancient continental metamorphic gneiss, from two separate continents merging, during the creation of Rodinia
Wow that's so cool! New Mexico has the coolest geology!
@@GEOGIRL you’re right, we have almost the entire geologic record of the world here, we definitely have representation of the entire Phanerozoic. We also have some or the best examples of volcanism in the country, aside from Hawaii and Yellowstone
Earth. This is so cool. By the way, I have difficulty communicating because I had a stroke in Broca’s area, the part of the brain that controls speech. 2/8/2021 but I lived again. (My wife helped me compose this.)
Makes me realize I need to get married. Lucky dog haha
Wow! That is crazy, I am so sorry that happened to you. Thank you for going to the trouble of making this comment even when it poses such a challenge, that really means a lot. I am so glad you enjoyed the video and this topic, I agree this topic (and Earth in general) is SO COOL! ;)
You may have trouble communicating. However, you are not giving up and tackling a difficult field of study. I applaud for your learning. I am just old. I flunked geology in college when young. But rocks and features have always fascinated me. My daughter encouraged me to try learning some geology. I have found geo girl is helping me fill gaps and solve points of confusion. I admire what you are doing.
I had always wondered what made continental crust different from oceanic crust. That makes sense now, very well explained.
Thanks! So glad this video helped! ;D
You're becoming my favorite host here on UA-cam. Everything is correctly stated, which lends credence to anything I was not informed previously. You are one of the few individuals who correctly uses terms like "hypothesis", "law", and "theory". In short, you do not get under my skin with statements such as: there are different theories out there that need verification. You correctly give their name: hypotheses. I already stated on a different comment that you deliver topics with a unique style. My sincere congratulations. You dignify this medium.
Always love your work... that name you couldn't pronounce is Mo-ho-ro-vich-ich, it's Croatian, there is even a site I found called Forvo Pronunciation, who has what looks a hundred languages or so, and thousands of pronunciations. I may have found a new site to kill time on. I also learned that Andrija Mohorovičić is one of the father's of modern seismology.
It's a good day when you get a Geo Girl vid, find a cool new website, and learn a few different, but related things as a result of both.
Outstanding. That was the most absorbing Sunday morning breakfast for a long time, thank you! Answered questions I didn't even know I had.
Thanks so much! I am so glad you found it informative ;D
Each Spring when I watch ice breaking up on the lake I think of it as a bit like plate tectonics where the sheets of ice move on wind and water currents and some converge while others are overrides and broken up. Supercontinents of ice form and then break apart, it’s cool 😊
I find it very interesting how the Caspian Sea contains oceanic crust at the bottom (a remnant of the ancient Tethys sea), unlike all other inland bodies of water which were made by glaciers or rift valleys. So technically that would make it a "true sea", despite being fully enclosed by land. The same fate would befall the Black Sea should the Turkish straits ever close up
Yes, the Mediterranean Sea about five to six million years ago.
Another brilliant job! Thank you so much for your awesome content.
I've been sending my students to your channel, and they (and I!) have been getting so much out of it. Thank you.
Thank you so much! I am so glad you and your students have been enjoying and learning from my videos! Trust me, I learn soooo much from making these videos, so I am right there with you! ;D
Good one as usual! Just a couple of things. The oldest continental crust still in existence is closer to 4 billion years, if not younger. The zircons older than that on the Jack Hills are detrital. The rocks that host those zircons are much younger. The crust those zircons crystallized from is long gone.
Zircons preserved a fingerprint of the (Si-rich) environment they formed in, indicating crust 4.3 billion years ago. www.nature.com/articles/s41467-020-14857-1.pdf
Near where I live are several areas of serpentinite barrens - soil that has formed from ultramafic rocks that happened to come to the surface. Because of the heavy metal content and the low calcium, nitrogen and phosphorus concentrations of these soil, the areas have very poor vegetation and limited ecological development and productivity. So we should be extremely happy for partial melting and the accumulation of felsic minerals as the Earth’s crust differentiated. We say that the Earth is hospitable to life, but the ultramafic rocks of the mantle certainly aren’t! Hooray for tectonic plates!
Yes, thank goodness for tectonics and partial melting!
Thank you for clearing a few things up.
I think it might have been _my_ comment on your "Dating Earth" video that you are referring to, confusing Earth's crust with tectonic plates. 😮 Thank you for clearing this up. 😊
It's possible, I can't remember, but honestly, I wouldn't blame anyone for mixing those up because we use terminology that relates the two processes all the time! I think I was 3 years into my geology major as an undergraduate before I realized that tectonic plates can contain both oceanic and continental crust LOL ;) So no worries if it was you and actually thank you because you gave me this great video idea! ;D
@@GEOGIRL Oh, thank you very much. 😊
Your views on Marie Tharp's contribution and how she was treated throughout the 1950s through '80s regarding credit might also make an interesting video. 😉
At @0:50 the diagram show oceanic crust as a layer under the continental crust, even away from the subduction zone. Is that supposed to say Lithosphere or something?
@@lethargogpeterson4083 Hahaha I noticed that after filming and was also confused (I didn't make the figure and clearly didn't check it over very well lol) I think it is either supposed to say lithosphere or they were just trying to show the difference in oceanic vs continental crust thickness, but seems weird to me, I would've just excluded that if I had noticed before filming haha ;)
Love this channel!
Thank you! So glad to hear that ;D
Thanks you have given me lots of help with your videos. I bought a book on plate tectonics for c'mas. I have just started reading it. I saw this video and thought it might help as I progress. I follow Nick Zentner. My passion is volcanos. I have been curious about plate tectonics a bit. So I decided to start tackling my interests. You are one of the sources I will turn to when I need good explanations. BTW, I am 70+.
Wow that is awesome! Buying a plate tectonics book for your self-motivated education at 70 years old is quite inspiring ;D I aim to be in your shoes one day, never stop learning ;)
I am grateful to you for clearing up my confusion. I still have to take time to process your explanation on the distinction. 😊
I have to admit I am still curious about your thoughts on Marie Tharp's work on mapping the ocean floor and of how she had been treated for decades regarding credit for the discoveries made in that endeavor. 🙂
Yeah but so grateful she explains it so good. Seriously this is the stuff that gets confusing
Happy new year! Great video! Rolling through EP on the 8th. Not sure if I have time to visit school but I do need to try and hit the bookstore for some merch.
I watched this video and now I have some sense how continents formed on our planet. Wow. This is amazing to learn, and you're a great teacher! thank you!
Thank you so much! I am so glad you enjoyed the video and found it informative ;D
This video was terrific! I am requesting you to make a video on Wind System too. Recently I came across a question with a statement saying that the wind in the northern hemisphere moves in a clockwise manner. How is it even possible to generalize its movement? Is this even true? In low pressure, it will move anti-clockwise, and in high pressure, clockwise in the Northern hemisphere as per my understanding.
So in short, we live on the scum on top of the Earth, accumulated by the convective recirculation of lithospheric material as the Earth’s heat is convected out. Like the scum formed on the surface of a pan when boiling bones to make meat stock. Nice image there Rachel 😂
Rachel, that was presented perfectly! Enjoyed every minute of it! Learned a lot too. 😁
Thank you so much, I'm so glad you enjoyed it ;D
I think I'll show your videos to my kids 😊 will help them understand Earth Science 👍
Thank you so much! I hope they like them ;D
Very nice, especially the suppercontinent part!
Love this content.😊
I would love to hear your take on chthonic worlds and how they [theoretically] might behave during formation, while still inside their ice- and gas giant hosts, and how they might behave if and after their hosts are vaporized.
Thank you for such a wonderful and informative video
Of course, so glad you enjoyed it ;D
Good info. I have wondered for a long time what the difference was between crust and continental plates. Now I know.
Great thank you geo girl
Great video! Very clear, simple and understandable. Thumbs UP
Thank you so much! So glad you enjoyed it ;D
The penny finally dropped on why the edges away from the spreading zone subducts; thicker, cooler therefore denser and heavier! Older=thicker=cooler=denser=heavier!!!
Very well explained, even I understood it.
Haha thank you ;) So glad you enjoyed it!
Very nice video...geo girl 👏👏✨
Excellent presentation -- a good review for me -- Thanks -- from Ron of the Rift valley -- lol.
Great video! Thanks for clearing this up for so many. Geology can be quite confusing sometimes for sure. Awesome job as always!
Thank you! ;D
I'd be lost on this if I hadn't watched the one with the phase diagram. That's been super helpful, I know you've done a bit on phase diagrams but I'd love to see you connect the diagram to real life somehow (by description or whatever) to give us an idea of how it translates? I don't know if my question makes sense, I don't know how to say it. Examples? Idk. I feel like I'm nearly ready for a field trip 😂💖
I totally get what you mean! That is actually a great idea, but will be difficult to figure out how to do because I never had that done for me haha, but I think I have some ideas on how to do it actually ;D I will have to play around with some ideas and test them on my geologist mom lol, but I am absolutely putting that on the future video list ;)
I got a question that came to me as I watched the video: when continental plates break up, as we know they do eventually, do they break along the suture lines of former continental fusion or do they create new fault lines in the middle of nowhere (or maybe both)? I understand that this is probably not perfectly understood but I imagine geologists do have at least theories on this matter.
Ah, this is a great question! They break along both :D It seems they have a history of breaking along either old sutures or completely in the middle of nowhere, but I'm not sure if one way is more common than the other, for that I'll have to do some research ;)
@@GEOGIRL - I've wondered the same thing as Luis. The most obvious example I can think of is the long-term stability of the Gondwana supercontinent. It formed 550 million years ago, and broke up about 180 million years ago. And in between it attached to - and separated from - the rest of Pangaea (350-200 million years ago). If I had the time, I'd research exactly how closely the break-up of Gondwana and Laurasia corresponds with the collision zones of Gondwana and Laurussia. But if we call the continent "Gondwana" both before and after Pangaea, the sutures and subsequent rifting must be fairly close!
@@GEOGIRL - I look forward for the future video on this matter, once you have enought time to properly research it. I find much easier to understand why continents merge than why and how exactly they break apart, really.
When stress is pulling on continental crust it tends to break at the weakest point(s). Cratons contain colder and thicker continental crust and are least likely to break. But the mountains which formed during a previous collision will contain faults. This includes the faults which formed when the mountains were built and the faults which helped bring them down through gravitational spreading/collapse. Besides that, the lithosphere beneath the mountains is likely to be warmer and weaker than cratonic lithosphere. When a continent splits the entire lithosphere is involved.
If there is no mountain range which contains faults going in the right direction, then the next weakest areas will probably be old hotspot tracks or rift valleys. If nothing is available then the continent and the lithosphere beneath must undergo stretching for a long period of time, enough to stretch the crust, create a new rift valley, and bring the lithosphere to the breaking point. The East African Rift valleys have been undergoing this for about 25 million years and the split hasn't happened yet. The so-called Somalia Plate has not yet detached from Africa, though the rift valleys are widening, and the relative motion is about 6 or 7 mm per year. For comparison, the Sierra Nevada block is still considered part of North America (by most) but is moving northwest relative to the craton at around 12 mm per year. California just might detach from North America before the Somalia plate leaves Africa. :-)
@@steveboguslawski114 - So they tend to break at the mountains? I've observed some of that in for example the early breakup of Pangea but was not sure if correct. I would have thought that mountains, being not just tall but also deep, would be behave somewhat like the most solid pieces, a bit like cratons, but seems I was wrong.
The next question (and I think this one is a tough one) is why or how does continent-breaking stress builds up through the ages. I understand (I think) subduction (and associated "coastal" volcanoes) and mid-oceanic rifts (the crust is very thin there) but breaking up a continent seems to require not just extraordinary force but sustained through millions of years maybe, what can cause that? A mantle plume maybe?
What you say of the Rift Valley is interesting but, while the Somalia "continental failure" (or very long delay) is intriguing, Arabia already split from Afirca (imperfectly as it may be because of further collisions). In any case what is "hammering" between, say, Arabia and Africa, what did "hammer" Pangea?
love this🎉
thank you it was interesting :)
Have you made a video about large igneous provinces and traps yet? I think I've watched most of your videos but I could have missed a few.
I have not, but I will look into it! I am currently working on some videos about OAEs (ocean anoxic events) in Earth's past that were triggered by LIPs so that would be a perfect segway into research for an LIP focused video :)
'Facts in Motion' did a couple of videos a few years back:
• The Most Dangerous Type of Eruptions - Flood Volcanism explained. ua-cam.com/video/st_2C_Wrw4A/v-deo.html
• The Largest Volcanoes in History - Mantle Plumes explained. ua-cam.com/video/NrbdYcNTo7Y/v-deo.html
Excellent presentation
Thanks, so glad you liked it :D
Thank you
Moon creation hypothesis and upper core bumps. Also carbon life lubricating tectonics.
It also just occurred to me - the process by which Earth differentiated over time as it cooled also has a psychological application. When we are young, we are poorly differentiated. As we age, our minds stratify. Well... one might hope they would. How much of one's maturation is experiential, and how much is mechanical?
😃 Great video. I learned a lot. 🤔 And then I thought of another distinct layer the Earth has on top of the crust, is Frosting! (Meaning ice caps, ice sheets and glaciers.)
I love thinking of it as 'Earth's frosting' that is great! ;D
This sent me to space wiki to learn new concept 😊
Gotta love wiki!
Thanks!
Thank you so much for the super thanks! I am so glad you appreciated this video :D
I'm a linguist by birth (a complex story), physicist by education, and applied mathematician by trade (speech and language understanding). I learn anything that catches my interest, from music theory to pure maths. But I never understood geology, and I'm living in California! When I drive through the state and looking at the mountains, I imagine how much a geologist could read looking at them! Thank you for your intro series! Maybe I'll get the basics and then grab a textbook.
A question, if you don't mind. You likely know that the dominant theory of the Moon formation is an early Earth collision with a Mars-sized body, Theia. This should have deposited a lot of energy into the early Earth-it should have remained hotter for a longer time than it otherwise would. Neither Venus¹ nor Mars, the other two rocky planets², have plate tectonics. Is development of plate tectonics related by geologists to this extra heat that the Earth has received from the Moon-splitting collision? A subtext here is why Earth but not the other two?
______________
¹ A similar collision of a certain scale experienced by Venus is not off the table, but there is no direct evidence, except its weird own rotation. But there's no tectonics, the whole planet is a solid eggshell. And this crust is only a few hundred Ma old. Apparently, Venus experienced a global resurfacing fairly recently. Whatever the event was, it erased all observable data: all we have is a few transparency windows in the radar range, and will hardly get a drilled core sample in the next 100 years, our current tech is not up to the task... In the end, all we know is Venus has no tectonics.
² Mercury is too different in structure, thus excluded from the “rocky planet” family. It is said to be a planetary core that failed to accrete enough material to become a bona fide planet.
Could you please cover Ophilites and Greenschist? :-)
You never mentioned the Cratons; What are they ? Where did they form ? How do they relate to the plates and crust ?
Oh that would be a great follow up video to this one! Thanks for suggesting this ;D
In the lava lake at the Kilauea volcano caldera, you can see what I envision as the early molten surface stage of earth's history. Watching pieces of crust form and move over the lake seems representative of these early stages.
This is for those of us who are nuts about plate tectonics.
Oh that was good. I had conflated crust and plates without realizing it. Am I correct in thinking cratons were the earliest solid bits of land? Eg the Canadian Shield was (is?) a craton.
I think the first cratons were accumulations of island arcs scraped off subducting oceanic plates.
A great visual to use for the thickness of lithosphere compared to the rest of the planet is a slice of cheese on a soccer ball. It's roughly the same proportion.
I would like to note that we don't really understand planet formation and there are a number of reasons to doubt that model of planet formation. After all if the standard accretionary model were correct we would expect more differentiated planets and particular isotopic ratios depleted of lighter isotopes of gaseous elements which we haven't found. Instead Earth's Nitrogen and hydrogen isotope ratios matches that of undifferentiated rocky material. As for the planets we have learned they aren't as differentiated as we expected especially in the case of Mars Jupiter and Saturn the 3 planets which have had missions probe their interior structure either via gravity harmonics(measuring the signal time delays caused by the gravity of the giant planet) or seismic tomography for rocky Mars. What we have found for these 3 planets the only planets that have been probed to this level of detail beyond Earth and our Moon tells us that they have far larger more diffuse and thus less dense cores than Earth or our Moon.
Now the best evidence for another model comes from Long Baseline Interferometry telescopes showing very early protoplanetary systems which indicate fully fledged planets are already present quite early on as well as closer to home the flyby of 486958 Arrokoth by New Horizons which appears to show a system fossilized in a state of relatively gentle direct collapse and assembly.
In each case we see evidence that planets form much quicker than accretionary models can support disk instability driven collapse is perhaps the best model to explain this as here planets much like stars form from fluid instabilities in this case within the accretion disk of a newly forming star where depending on the circumstances gaseous icy and or rocky/dusty planetesimals are able to coalesce from the infalling gas ice and dust particulates that compose the giant molecular clouds which stars form in thanks to fluid instabilities in the molecular component of the accretion disk serving as sinks of angular momentum allowing the surrounding bulk flow to continue to flow towards the source.
486958 Arrokoth appears to show us a fossilized perspective of icy disk instability driven direct collapse forming a large icy planetesimal relatively rapidly in the far reaches of the disk whereas worlds and even small stellar mass bodies detected by interferometry in protoplanetary disks show objects have already formed before the central protostar has gotten hot enough to ignite. In all likelihood this is probably a natural process where accretion continues while still conserving angular momentum by forming clumps of material from eddies which will then begin to differentiate and or accrete if massive enough.
Now Mars Jupiter and Saturn are what we term fist generation planets as they formed directly from the solar nebula Earth and our Moon however are 2nd generation worlds because we now have fairly strong evidence to suggest they both formed as a result of the violent collision between the proto-Earth and a originally Trojan planet Theia which eventually orbitally destabilized and crashed into Earth. This collision based on more recent simulations was almost certainly violent enough that both proto-Earth and Theia would have been volatilized and then thanks to conservation of angular momentum and their high gravity they would have collapsed into spheres of liquid/ supercritical fluid held together by surface tension and gravity on timescales which have only decreased as the resolution of simulations has been increased with the most robust models showing only a matter of several hours for the Earth and our Moon to have formed from the debris. Under such rapid formation there is no longer a need for secondary delivery of volatiles as has been conventionally assumed and more interesting it would suggest Earth's water was also already in volatile form which given the sheer quantity identified in the mantle would have been more than enough for push said water into its supercritical state which would completely bypass the need for a phase transition into liquid. Boom Earth's otherwise anomalously early oceans can thus be explained fairly trivially since supercritical fluid generally phase transitions to a mixture of both its liquid and gaseous phases if possible.
Beyond that have you been following some of the fascinating discoveries with Seismic tomography? Some of those seems to suggest that the motion we attribute to plates is more broadly linked to the upper mantle in that we see for example upwelling more buoyant mantle boundaries contiguous with the termination of subducted slabs and with active mid ocean ridge systems. Some of the papers Nick Zentner linked seem to suggest we redefine a newer deeper tectonic paradigm which incorporates the structure we see in the mantle. I certainly am partial to that approach as Its hard to interpret the results under North America another way when the data from igneous and volcanic material dating paleomagnetism and seismic tomography are brought together.
It finally makes North America's geological wreck readily explainable.
Would the first differentiation have been at the initial cooling with minerals that solidified at a lower temperature, and have a lower density essentially floating to the top?
Does the Moon have a role in starting and sustaining plate tectonics? I am looking at the difference between Earth and Venus. Since the moon was much closer to earth just after formation, the gravitational kneading of the earths surface was much greater. Has the calculation been done on how much energy the moon’s gravity exerts on the earth just after formation?
Yes, I believe that calculation has been done, but from what I understand it's not that the moon played a role in starting plate tectonics, but rather intensifying it because it provides energy (heat) for convection. Ever since the moon formed, it's gravitational pull on Earth has provided some interal heat (tidal heating) to Earth (and vice versa), but since it is relatively small and far away the amount of heat the moon generates on Earth is minute compared to radioactive decay of isotopes within Earth, solar radiation, gravitational compression, & back on early earth, impacts from bombardment. The moon forming impact likely contributed heavily to heat that drove early melting, differentiation, and convection on Earth, but after that heat dissipated, I think the heat contribution of the moon has been small relative to those other sources of heat, and thus, the moon's role in maintaining plate tectonics is likely small (but I am definitely no expert, this is just what I grasp from what I know about tidal heating on Earth, so I could very well be missing something that makes the moon a larger component). That's a great question! Let me know if you find any more info on it ;)
@@GEOGIRL One big difference is water. Earth is water rich while Venus has lost whatever water it had. Water lowers the melting point and strength of rock and this might be how plate tectonics is maintained. Dry oceanic crust might be too stiff and strong to subduct easily.
So... is New Zealand actually a continent? Since it's actually a continent sized piece of continental crust even though most of it it is under water.... or so I've heard.
I see Greenstone feaured in one of the slides on Continental Plates, please tell more...
I dare you to take a drink every time she says “felsic”.
Amazing how young the ocean floors are. Much younger than sharks.
8:57 I'm hearing more Mafic than Mafic to the tune of More Human than Human bt White Zombie
On the slide about early crust differentiation, @5:50-@7:00, the word "heterogeneous" appears a couple of times. Wouldn't it be starting from "homogeneous" at that point then differentiate to heterogeneous? Or am I missing something?
when was the first time, ice could have formed on the earth? it couldn't have been before the impact that created the moon? but it must have been on the poles (long?) before an ice age. What effect does the formation of the 4°C_ocean_bottom_water_layer have on other geologic processes in the ocean?
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Excellent. I've subscribed and shared it with interested relatives. I have a better title for the video: 5 Billion Years on the Earth's Surface Layers in 20 Minutes
Thank you so much! I am so glad you enjoyed and shared it ;D
@GEO GIRL
This occurred to me while watching and might be useful info: I think that when the initial undifferentiated crust was formed and later was transformed into oceanic crust and continental crust, the oceans didn't exist yet! So there were two types of crust, one heavier and at a lower altitude, one lighter and at a higher altitude. Much later, when water vapor condensed, it flowed onto the lower crust to form oceans, hence the name oceanic crust.
Following up on Fei Fei Li's advice to identify the North Star navigational aid for direction finding a lifetime objective, the ultimate is Singularity-point reciprocation-recirculation coherence-cohesion sync-duration resonance quantization and holography dimensionality, because in geological properties of recognising sync-duration temporal functionality, all materialisation has "triple point" phase-locked coherence-cohesion characteristics derived from point-line-circle 0-1-2-3ness string-like nodal-vibrational emitter-receiver quantization cause-effect that self-defines real phase-locked properties of materials.
Out in the field, as Geologists say, ages and duration of elemental bonding under scrutiny in reciprocation-recirculation information In-form-ation substantiation Convection, is "where it's all at", temporal thermodynamical real-time Superposition-point Actuality.
Are there any ideas on how long it took for the proto earth to go from a group of materials attracted to each other, to a molten lump in the Hadean, to the first slightly solid crust?
I was confused when I read an article that said that Continental Crust actually contained more iron than oceanic crust. I've always assumed that oceanic crust contained more iron.
It makes it tough when there are conflicting theories about Plate Tectonics. I've seen some that said that Plate Tectonics were slower when the mantle was hotter, and didn't speed up until a Billion years ago. Whenever we nail down some answers, new ones pop up.
Oh gosh, that's a great question, I think there are many ideas on how long that took, but I think they are pretty wide ranging. However, the range is typically within the Hadean eon (so from 4.55 to 4 billion years ago) before the Archean. From what I've read, it seems the first heterogenous global crust formed potentially as early as 4.4 billion years ago, but it wasn't until the Archean that continental pod accretion into larger continental landmass occurred (~4 to 2.5 billion years ago). I think there are still many different hypotheses on this, but the trend (from what I've seen) seems to be that more recent studies always estimate a more ancient crustal formation period, so we keep pushing things on Earth back almost to just after it formed meaning that things like differentiation and crust formation got started almost immediately after the moon-forming impact ~4.5 billion years ago :)
@@GEOGIRL Thanks.....Every decade we learn new information. Theories change constantly. 50 years from now, the origin date might be pushed back to 4.9 Billion years. (if you start with the first accretion)
@@GEOGIRL Yes, I was missing a mention to Theia and guessing you cover the theory of the impact in some other video. I'm thinking that plate tectonics was likely incremental after some (at first localized?) threshold of hydration of the lithosphere was reached. Perhaps you will do a video on the importance of water to the strength (relative weakness) of Earth's crust to that of non-hydrated crusts (Venus?). Glad to have found your channel today. Looking forward to listening to all of your efforts!
I have a question? How did the earth or any other rocky planet or moon differentiate? To my intuition individual atoms move too chaotic to get pulled down by gravity.
When the planets and moons were just forming by accretion, the heat from gravitational compression, radiactive decay, and constant bombardment kept the material molten enough for long enough that the dense melts sank and less dense one rise. Actually this is still going on in magma chambers on Earth today, the denser magma sinks to the bottom of the chamber and the less dense magma rises. The less dense magma also has a lower melting point so it ends up melting first as the temp rises and this leads to a continuously lower density of magma that is erupted at Earth's surface compared to what remains in the chamber. On Early earth, it was like the whole planet was the chamber, but temp was high enough to melt it all, so the more dense magma rich in Fe sand to the core and the less dense silica rich magma rose to the surface. Hope that makes sense :)
@@GEOGIRL Thanks for your elaborate anwser! I have been bingewatching your video's and I must admit that I am completely overwhelmed by the quality but allso the enourmous amount of content you made! Back to the question, I can more or less imagine how near the surface heavier stuff becomes solid and sinks leaving the lighter stuff at the surface. But still I find it hard to get how the core separated from the mantle, just because it is "liquid" or "plastic":. On house, garden and kitchen scales fluids don't unmix by gravity. (unless you get a separation like you have with oil and water, but I do not think that kind of physics plays any role at the scale of planets. ) I can imagine blobs from an asteroid with a lot of iron sinking and a blob with more aluminium rising, but I still find it mindblowing that stuff has been separated to a higher degree than the initial blobs, against all the radioactive heat wanting to escape from the center by means of convection, and the crazy tidal forces in the Hadean era. Still boggles my mind, but that is part of the fun.
Felsic is my new favourite word
i know an ed felsic in brooklyn. 😂
Dad joke time! Felsic is what the guy did after he went outside in the rain without his jacket.
Earth appears to be missing most of its crust. The remaining crust sort of "floats" around on the mantle, hence the plate tectonics.
Hello Geo Girl - Seems that crust formed before plate tectonics. I wonder why the plate tectonics started after the crust formed? I keep thinking asteroid/comet impacts.
Everything about plate tectonics is driven from below (mantle convection), not above, so I doubt that impacts on the outer surface would've affected it (but I could certainly be wrong this is just my initial thoughts on this). And right when crust formed on earth and became brittle enough to move around on the plastic athenosphere, plate tectonics began (so they really coincide more so than one happened then the other, it's just that on early earth things were hotter and more molten, so the plates didn't subduct quite like they do today, it was more mushy and bouyany if that makes any sense...) This is hard to explain in words, but I have a video coming up about the Boring Billion that has a good figure showing the difference between this 'early' style of plate tectonics and modern style plate tectonics, so make sure to check that out once it is posted ;)
@@GEOGIRL the "boring billion!"
the Moon was a lot closer back then; so, the tides and waves were crashing on land a lot harder back then. It would have been something to see!
By the time eyes evolved, the Moon had already moved a good bit further out . . .
So, there is an oceanic crust (fig. 1) under the continental crust? ;)
Haha yes, many plate tectonic figures don't do a great job of distinguishing between crust & lithosphere, but we gotta work with what we got lol ;)
I like how you make yourself tiny for the lecture. It highlights the material. The real fans don't care that you have an easy face, we love approachable geology.
perhaps you could draw some of the diagrams yourself .. . . they don't have to be great to get the point across, but it would add nuance to your brand.
but, that's a time sink, you might have a life. My offer of rallying the subscribers to get you a poster and a mars globe is still valid.
Hahaha yea, I've started making some figures myself for some of the videos (mainly the ones in my research field because I feel more qualified to do that lol), so hopefully my future videos will have more of my figures sprinkled in ;)
A planetoid named Tethys struck the earth. Earth material flung into orbit gravitated toward each other and formed the Moon. We must have Tethys' remains churning around in Earth's core and other layers in an asymmetrical fashion.
I don't know when Tethys struck. I think it was named Tethys.
I had seen another video that addressed accretion, but yours went way beyond it! 😊
So... the expulsion of felsic from mafic materials away from the center of gravity is kind of like in cooking when a sauce "breaks." Man, I love geology! What would an emulsified Earth look like?
We also aren't even sure when plate tectonics began. It's actually one of the biggest debates in Precambrian geology. Most Precambrian workers (other than the old timers) think plate tectonics actually didn't begin until the late Archean (3.2Ga) or end of the Archean (ca. 2.5Ga) Some other tectonic process was in play. One such tectonic regime is lid tectonics. The Archean greenstone belts do not match any plate tectonic regime.
Subduction and crustal recycling aren't synonyms for plate tectonics. Plate tectonics has a very rigid definition. Pun intended.
Yes! I was just reading about lid tectonics for my upcoming boring billion video. Although I have to admit I stayed away from actually discussing it in my video because I didn't fully understand it... I just said it was different than 'modern style' plate tectonics haha. Do you have any videos or know of any good reference that explain lid tectonics in a way I might understand?? Thanks !! ;D
@@GEOGIRL you did good! If you ever have any Precambrian questions. I'm available. The Paleoproterozoic and Mesoproterozoic is mostly where I dwell.
Just a quick thing on the boring billion. I don't study life. You're better at that than I am. Tectonically it was not as quite as often portrayed. I can think of at least a dozen major tectonic events In Laurentia alone during that timespan.
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If the crust started forming 4.4 billion years ago, how did it survive Thea’s impact that turned everything to magma?
Thea impacted around 4.5 billion years ago, over 100 million years before crust began forming. I think there are some hypotheses/models that suggest crust attempted to form or start forming before Thea impacted but the impact set back the crust formation schedule just a bit :)
@@GEOGIRL thank you
@@GEOGIRL was the Thea impact responsible for the formation of Earth’s core and magnetic field? It seems to me that the Thea impact may be why we have a magnetic field that protects the planet, and why our water wasn’t stripped away like that on Mars.
@@bfg1836 Oh that's an interesting thought, I actually have no clue haha (I have strikingly little knowledge about the magnetic field and when it formed), but I think your hypothesis sounds resonable to me! If anyone reading this comment knows about the magnetic field please reply and enlighten us! ;D
I will do some reading and see what I can find ;)
I need
Accrete? Like glue? Wait, I'll google
Ooooh gradually formed accumulatively. Right-o. Got it. Thanks! 💖
In my presentations I present God forming oceanic crust on day 1. On day 2 He separated water under and above the continental granite crust. On day 3 He created the mid oceanic ridges and placed the continents in the current positions
2:47 - Sorry, Prof., but I believe you made a major error when talking about how the solar system formed: AFAIK it was not directly created from any supernova (which would at best have an indirect influence) but by the collapse of a cosmic gas cloud at one of those so-called "stellar nurseries". These clouds were surely seeded of "metals" (materials heavier than helium for Astronomy) by supernovas in the past, which is what you probably had in mind and maybe nearby supernova explosions helped with the gas cloud perturbations leading to the stellar formation collapse but a supernova leaves a remnant at the core (neutron star or black hole) and not a main sequence star.
Oh how cool! Thanks for this clarification, I got my explanation from a geology textbook that probably simplified it way down to a not so accurate depiction, so I appreciate this comment! I am a much better 'geo' girl than 'universe' girl hahaha, so I will make sure to correct this for future videos ;)
@@GEOGIRL It's all quite complicated so you've got quite the pedagogic challenge. While supernovae are the source of many of the elements beyond He, even that is problematic for the very heaviest elements. See recent papers on neutron star collisions for the formation of the heaviest elements.
Anyway, a simple solar system as ours probably condensed out of a large gas cloud, as Luis mentioned. Said cloud would have had interactions with the outflow from novae, supernovae, neutron star events, etc.
Wonderful term -solar nurseries
@@GEOGIRL - Now that you're working at astro-geology, you are not any more allowed to ignore that. ;p
@@barbaradurfee645 - *Stellar nurseries. There's only one Sun but "zillions and gazillions of stars" (paraphrasing good old Carl Sagan).
Magma model is a lie.
I wouldn't want to date Earth. I feel like Ouranos wouldn't appreciate it..
Terra , dearie . The planet·s name is Terra . The name "Earth" comes from the Sumerian god Ea who originated from the constellation Vega . The Catholic Church , the Scandinavians , the French , we call it Terra , and Terran Intelligence reflects this . Domini est Terra .
#ProjectStrix #DominiEstTerra #TerranIntelligence
"The Catholic Church , the Scandinavians , the French , we call it Terra " - Latin derived languages and regions that use them, use "terra" for earth, the ground. That is the Latin word. But there is another Latin word, "Tellus", for our planet. The Germanic languages (Norwegian, Icelandic etc.) use "Jord" (or a spelling variant), not "terra".
" Domini est Terra " - your religious obsession is noted, but it does not bear upon the reality of the rest of us.
dont get it twisted dearie. youtube, the material, the presenter and your own post are all american and/or in english, so no terra, its earth. terra is incognito. 😂
From the Online Etymology Dictionary: Old English eorþe "ground, soil, dirt, dry land; country, district," also used (along with middangeard) for "the (material) world, the abode of man" (as opposed to the heavens or the underworld), from Proto-Germanic *ertho (source also of Old Frisian erthe "earth," Old Saxon ertha, Old Norse jörð, Middle Dutch eerde, Dutch aarde, Old High German erda, German Erde, Gothic airþa), perhaps from an extended form of PIE [Proto-Indo-European] root *er- (2) "earth, ground."
I like crust!
Me too!