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@RWBHere3 ай бұрын
Thanks Shawn. 🙂👍
@seanmccaul30343 ай бұрын
Wow, another great video Shawn! Thank you so much for this series! Can’t wait to learn more about convergent plate boundaries. These explanations are really helping cement my understanding of these concepts! One question that comes to mind is to what extent rifting pushes the continental crust versus subduction in other places pulling the plate boundaries apart? This came to mind when you were discussing the decreased pressure at the surface of the crust promoting magma formation in the aesthenosphere. Maybe pushing and pulling are the wrong concepts to apply here, but those were the words that came to mind. Thanks again!
@shawnwillsey3 ай бұрын
Slab pull is more dominant than ridge push. You can see evidence in speed and number of quakes along subduction zones.
@seanmccaul30343 ай бұрын
@@shawnwillsey Thanks Shawn, that makes sense to me and helps me better understand the process!
@Dragrath13 ай бұрын
@@seanmccaul3034 To add to what Shawn said it should be noted that slab pull is a gravity dominated process as the subducted slabs sinking down into the Earth effectively drag the rest of the plate with them. You can consider the ridge push to largely be a response to the pulling of slabs, though there are of course exceptions particularly major mid ocean ridges with hot spots of upwelling material which seem to have deeper origins i.e. the East Pacific Rise and Mid Atlantic Ridge. Nature loves exceptions, the rate of sea floor spreading between mid ocean ridges can vary by up to 2 orders of magnitude for example though again as Shawn said subduction generally is faster. The seismic tomography stuff is adding fascinating details to the picture too for example it appears that subducted slabs under go remineralization as the sink deeper into the planet and get subjected to higher and higher pressures which forces out lighter incompatible elements/volatiles and then causes the slabs to sink even more. There is some evidence to suggest they sink all the way down to the core mantle boundary before they get remelted by the heat of Earth's core and contribute material to the upwelling plumes of material rising to Earths surface. In essence the slab itself is the Earth's downwelling convective element.
@seanmccaul30343 ай бұрын
@@Dragrath1 Thanks for the additional information! That’s why I love this channel, always learning something new!
@kathypike52933 ай бұрын
I've now watched all three of your Geology 101 videos and they are great!! Thank you for doing this....I've always been fascinated with geology, volcanology and pretty much all earth sciences but as a single Mum of 4 kids, school wasn't an option but now that my youngest is 18, it's time to go back!! I'm watching these videos hoping it will help me choose a direction in school!! Thank you for all your hard work and being a dedicated teacher!! Keep it up 😊
@shawnwillsey3 ай бұрын
Awesome, thank you! I love your story.
@userpharnorth3 ай бұрын
Shawn thank you for all the geology you are putting out there. I am overjoyed for this series you are doing on beginning geology. Again thank you.
@celiabell94663 ай бұрын
Really am enjoying this. I took geology in the mid 1960s when they were just beginning to teach tectonics. There was still some doubters around. There's was no Google earth or internet so this is really great.
@kaboom46793 ай бұрын
I still have a few old geology textbooks around that treat plate tectonics as a new and controversial theory .
@muzikhed3 ай бұрын
Super. A good knowledge of the basics makes everything after more comprehensible.
@wordswords20943 ай бұрын
Excellent! Thank you!
@joannekellam1913 ай бұрын
Thank you!! Great information and so clearly presented, as always! That little peninsula on the east coast of the US where you drew your line for the Mid-Atlantic Ridge is the Delmarva Peninsula, the southern part of which is in Virginia and my home area. ❤
@gembay3 ай бұрын
Would the Upper Rhine Graben be also considered a divergent boundary? From what I know, the plain is still experiencing subsidence, but is being supplied with new sediment at a rate high enough to not form a deeper valley.
@valoriel44643 ай бұрын
Thx Prof. ✌🏻 really appreciate this series.
@Moozac3 ай бұрын
I got the right answer! Only because Shawn explains things so well.
@stephanieparker12503 ай бұрын
I’m loving this 101 series!
@oscarmedina13033 ай бұрын
Thank you Shawn. Very enjoyable presentation.
@shawnwillsey3 ай бұрын
Glad you enjoyed it. Thanks for your support.
@garyb62193 ай бұрын
I love this series. Is there a theory that takes an upwelling of magma into a tear that is thousands of miles long? Is there an initial start to the mid-atlantic ridge identified?
@youtubeaccount9313 ай бұрын
Really appreciate these videos. Thank you so much.
@JanetClancey3 ай бұрын
Another fantastic episode… I learn and find great enjoyment in it … I love planet processes.. thank you shawn
@Fieldwalker2643 ай бұрын
Excellent, thank you.
@poppyagnew3 ай бұрын
Excellent Series. Thank you for your diligent efforts.
@helenhill70143 ай бұрын
Wow I never studied geology at school. So interesting to learn something new through your fantastic videos. Thank you!
@noahhornak63083 ай бұрын
Hi Shawn, thank you for doing this series, I've been really enjoying it! One question I have that maybe I'm missing the concept for is why in the Mid-Atlantic rift, there is volcanic activity and new crust staying at a higher topographical point but as shown with the divirgent plate boundaries of East Africa and The Red Sea, we don't see that and the place of divirgence is at the lowest topographical point?
@marcialoofboro3063 ай бұрын
Interesting, I had figured out the center would be shallow but didn't realize there wouldn't be any others further out. Thanks for the class!
@rachelw93363 ай бұрын
Shawn, thank you for making an incredible series! I am absolutely loving it and you’re a natural born teacher! Thank you so much for these videos. Can’t wait for the next one
@shawnwillsey3 ай бұрын
You are so welcome! Thanks for watching.
@sueellens3 ай бұрын
Thank you! I need to stick with my first choice when it’s multiple choices! 😂
@causewaykayak3 ай бұрын
Yes, super interesting. Looking forward to episode 4.
@JorgeSanchez-uk4cb3 ай бұрын
Thanks professor 🙏 Rio Grande rift by the Jemes Mountain in the US state of New Mexico. I always wondered if if goes all the way up to Salt Lake. Professor is Salt Lake a sag pond? 🤔
@FionaMacintyre-o8p3 ай бұрын
Hi Shawn, I am so excited to have found your channel and now that you have these videos. I have a rough idea from school, a long time ago so enjoying having my knowledge enriched.
@pukulu3 ай бұрын
For every successful rift on land in the middle of a continent, there probably are several failed rifts that leave behind long, thin lakes such as Lake Baikal. Why rifts succeed or fail is an interesting question. The rift in East Africa seems to be succeeding but we can't be sure. Lake Tanganyika and Lake Malawi are signs of a rift in any case.
@kaboom46793 ай бұрын
North America has many such failed rifts , including the New Madrid seismic zone . Farther north from Michigan through Minnesota was another tremendous rift that simply filled with basalt and stopped , but brought massive amounts of iron ore , copper , and other metals along for the ride . Meanwhile the Rio Grande Rift is slowly tearing apart the southwestern US and on into Mexico . Nothing is forever .
@pukulu3 ай бұрын
@@kaboom4679 thanks!
@peresjohn97633 ай бұрын
Asante sana mr shawn..
@georgefox70412 ай бұрын
Thanks!
@shawnwillsey2 ай бұрын
Thank you for your support.
@scraigdeaton80562 ай бұрын
Thanks!
@shawnwillsey2 ай бұрын
Much appreciated. Thank you.
@stevengeorge56053 ай бұрын
Thank you, Shawn!🙂
@VanessaThompson-mw4ud3 ай бұрын
Thanks!
@shawnwillsey3 ай бұрын
Much appreciated.
@rosiealaniz32053 ай бұрын
Sooo looking forward to your 3rd lesson! Gracias!
@sandrine.t3 ай бұрын
Hey there, long week... But it's the weekend, hooray! Perfect time for a good geology lesson, so let's watch your Geology 101, episode 3. Thank you (again) for doing this, Shawn! (ps: pizza sent ;)
@shawnwillsey3 ай бұрын
Thanks as always, Sandrine.
@cindy84263 ай бұрын
Thank you, great video!
@sheilagraham85433 ай бұрын
Thank you for another great video Shawn. I was in my mid twenties during the 1960s when the theory of plate tectonics was first generally accepted: we’ve certainly come a long way since then in our understanding of our world.
@gailgreen50123 ай бұрын
Loving this. Thanks so much.
@jacquie-h45303 ай бұрын
Thank you for another great Geology video, Shawn. You make it easy to follow and the diagrams help me visualise the subject. I like that you are covering the different plate boundaries in different videos, that is giving me time to take it in and helping to get it into my brain. Brilliant.
@shawnwillsey3 ай бұрын
Glad to help!
@davidk73243 ай бұрын
Masterclass. Now I need to try and get my head around decompression melting.
@shawnwillsey3 ай бұрын
We can tackle that when we discuss igneous rocks.
@robmez3 ай бұрын
Very good once again
@lornaperryman4893 ай бұрын
Wonderful, wonderful, wonderful to quote the late Mr. Welk.
@PoppaBlaster3 ай бұрын
Hell yeah les go!
@sparkleflair2 ай бұрын
A quiz? I better listen more closely! Yes! I got it right!!! (Without going back and re-watching other videos!)
@scraigdeaton80562 ай бұрын
Excellent series, well done. Enlightening and enjoyable. You have a unique gift to share knowledge. QUESTION: as of 11-July-24 several large quakes occurring Juan de Fuca Ridge,west of Vancouver Island and on/near Cascadia Subduction zone. Is this an example of a divergent boundary? If not, how would you describe the tectonic activity ? Thank you
@DJDouglasWarden3 ай бұрын
Thank you
@ZYX2613 ай бұрын
DIVergent Plate Boundaries DIVide the crust. 😉 😊 Allowing hot, buoyant magma to rise, fill in the fractures, and making new crust. 😊 (Well done, sir, from a recently retired intro geology teacher. Dr. McClurg always told us to give them 'eye candy, keep it simple, know it like you know the back of your hand in order to tell the story, and don't baffle them with bs'. You checked all of the boxes!) 🎉
@MikeGreenwood513 ай бұрын
TY
@maryt28873 ай бұрын
Love the quiz! As a retired teacher, I appreciate the opportunity to reinforce my learning by thinking about a problem . Nailed it, too!
@user-wk1mw9nj3i763 ай бұрын
I don’t know if you have time to answer questions about the quiz; I understand how busy you are! (Quiz answer spoiler alert, viewers!). ❓I compared the ocean basin earthquakes plots to the Iceland erupting volcano situation and remembered that in Iceland there were small, deep earthquakes farther away but still possibly secondarily triggered by the rift area activity. On the map, off to the sides, roughly east and west of the rift zone. But the Atlantic Ocean basin rift does not cause earthquakes off to the sides in your quiz answer. ❓Could the reason for the difference between the Iceland earthquake example and the quiz’s ocean basin example be the smaller scale of the Iceland example (fewer kilometers involved)❓Approximately how wide is the Atlantic rift where earthquakes happen? I’m looking forward to the convergent plates episode. Thank you!
@professorsogol58243 ай бұрын
I have a question: At one point you said that the plates are being "pulled" apart at the divergent boundaries. Wouldn't "pushed" be a better description? Doesn't the upwelling magma force the plates apart? If they are "pulled" apart, what provides the attractive force?
@Bob-jm8kl3 ай бұрын
What I'm curious about is the African Rift Zone in context to its surroundings. It seems that the Red Sea, Dead Sea, and even Madagascar have to be related, if in only to the degree that with all of the planetary rifting going on, that portion of the globe seems to be particularly actively rifting. Inquiring minds go hmmm.
@DetourswithFrankАй бұрын
Thank you professor. Really enjoying this series. Now I just need to figure out how to get google earth to show elevation profiles.
@madmaddie49563 ай бұрын
Yay, one year of watching your podcasts and guessed the right answer on your pop quiz. Maybe in another year, I will upgrade to Knowing the answer instead of guessing!
@CraigInNC3 ай бұрын
❓️Why are there such elevated ridges outside of the East African and Red Sea divergences?
@kymkauffman5000Ай бұрын
Love the question to see if we understood . I was half right. I chose B.
@Faelani383 ай бұрын
I did learn something new today lol I was wrong on the earthquakes and did not choose e. Now I know different.
@chrismusix56693 ай бұрын
I'm interested in the mechanisms that cause the decompression melting.
@austinobambino13603 ай бұрын
Temperature and pressure both increase as you go deeper underground, however, at most depths the pressure is high enough that it prevents the rocks from melting despite the rocks being very hot. So decompression melting occurs when the pressure above already hot rocks decreases. The crust is thins out at divergent plate boundaries, thus the pressure above hot rocks decreases and those rocks are able to melt. It's similar to how it takes less heat to boild water at a higher altitude because the air pressure is lower.
@loisrossi8413 ай бұрын
Love learning something new, thank you.
@saimaleon711521 күн бұрын
Yay I figured out the right answer!
@Riverguide333 ай бұрын
👍
@aoifa_silverDragon3 ай бұрын
How can you make a cut like that in google earth?
@RoyScribner3 ай бұрын
Another great episode, thanks!
@jfmezei3 ай бұрын
QUESTION: In a different lesson, you told us that the crust below oceans is basalt, and on continents it is granite. In the case of diverging plates, dopes the lava that comes up to fill the gap end up as basalt or granite depening on whether under strong water pressure or whether neat ground level? Or doe the gap between two contine ts that spread apart remain lava in nature forever ? Since Québec used to be attached to France a few years ago (hence our common language 🙂), and you had mentioned the floor of the atlantic was basalt, but as the 2 continents drifted apart, wouldn't that imply that lava actually filled the gap between North America and Europe?
@lynnensley78793 ай бұрын
It has nothing to d with pressure. Basalt is a low silica product and granite is a high silica rock.
@Rocketboy-qg6ts3 ай бұрын
Ok, this was just amazing 😮
@juliehoffman62923 ай бұрын
I read recently that the Indian continent is splitting. Would that be a rift similar to the Rift Valley in Africa?
@tjenkens3 ай бұрын
Another great lesson! Is the basin and range a divergent plate boundary?
@shawnwillsey3 ай бұрын
It’s not a true boundary but an area of diffuse extension. It could one day become a plate boundary.
@wpherigo13 ай бұрын
I so did not get the quiz.
@johnnash51183 ай бұрын
Hi Shawn, Per Google Earth, the South Gorda spreading ridge not only borders the Mendocino Fracture Zone (MFC,) it’s 4,000’ higher than the adjacent San Andreas-Pacific plate opposite the MFC. The 4,000’ MFC escarpment is abrupt, dramatic and structurally consistent along its length from the triple junction @125W Longitude to @129W Longitude where the Gorda-Pacific plate appears to have spilled its magma over the escarpment onto the San Andreas-Pacific plate floor; at this location, the MFC escarpment is still @4,000’ in relief and from there onward, the escarpment is no longer abrupt nor consistent. Why the inconsistencies between 129W and 125W? Why no magma spillage over the escarpment West of 129W? The escarpment appears to be San Andreas-Pacific in origin and behaves as a natural dam impounding the fresh magma at the South Gorda spreading ridge. Any thoughts or observations?
@lauram94783 ай бұрын
❤❤❤
@johnplong36443 ай бұрын
Well this is great I have learned a lot from Nick’s 101 lectures
@highkicker113 ай бұрын
i would think a would be the correct choice but the amount of quakes would lessen the further away the new material would get from the birth place till the point it meets the continental crust and there the Quakes would increase again
@shelleyszulinszky97323 ай бұрын
❤✌️👍
@alicemiller31393 ай бұрын
I thought the rift zone in Africa was North/South, yet you said East to West. Did I misunderstand?
@charliekliewer26433 ай бұрын
A!
@guitsynthcw3 ай бұрын
I failed that quiz spectacularly.
@austinobambino13603 ай бұрын
I completed a Geology minor and got that wrong lmao
@briane1733 ай бұрын
I over-thunk it; there _are_ occasional earthquakes that occur away from the plate boundary itself, but Shawn never said whether it was a rift or a spreading ridge. My feeble brain went straight to a rift and so I was like doing B or whatever. At a spreading ridge underwater the quakes are 100% along the boundary itself.
@3xHermes2 ай бұрын
@DianeSmith-h3t3 ай бұрын
👍👍👍👍Di..Cumbria
@jwardcomoАй бұрын
Could a divergent plate boundary just be a "hotspot" on a much greater scale?
@shawnwillseyАй бұрын
No, because it has significant linear length and isn't a "spot." Iceland is both a divergent boundary and a hot spot though.
@jwardcomoАй бұрын
@@shawnwillsey Thank you!
@maryjokluth92082 ай бұрын
Thanks!
@shawnwillsey2 ай бұрын
Much appreciated
@georgefox70412 ай бұрын
Thanks!
@shawnwillsey2 ай бұрын
Thank you.
@drmichaelshea3 ай бұрын
Thanks!
@shawnwillsey3 ай бұрын
Thank you kindly.
@johnjConnellan3 ай бұрын
I live in metric area and thank you.
@austinobambino13603 ай бұрын
I mean... That's the vast majority of the world lol
@professorsogol58243 ай бұрын
@@austinobambino1360 to quickly convert feet to meters, divide by 3 and round down. e.g. 12000 feet is a bit less than 4000 meters (more precisely 3658). If you're going to be hanging around with those stick-in-the-mud Yanks, you need to develop a few tricks to convert units.
@Azivegu3 ай бұрын
I learned absolutely nothing, but I still loved the video. I want more geology on KZbin and you are providing. Thanks and rock on!
@Dragrath13 ай бұрын
Again I think you have the asthenosphere and upper mantle inverted (or rather the asthenosphere is part of the lithosphere and upper mantle) In terms of divergent plate boundaries it should be noted that continental rifts can get much more complicated often involving multiple competing rift centers before one eventually comes to dominate. A good example of such a well developed failed rift is the strait separating Greenland from North America ultimately the eventual split was to the east splitting Greenland from what is today Ireland and the Scottish coast of Britain. There is even another less developed failed rift or graben which forms the Irish Sea separating the two islands. One curious divergent plate boundary which breaks the rules is Gakkel ridge the ultra slow spreading ridge of the Arctic ocean which does produce explosive activity. The type of magmas erupted here are somewhat unusual as it seems a good amount of the volcanoes here have melt sitting long enough to undergo crystal fractionalization turning into more siliceous and chemically evolved melts which in addition to more typical pillow basalts build up stratovolcanoes lava domes and calderas with clear evidence of recent pyroclastic eruptive activity and even some older evidence for an extreme VEI 8 super eruption dated to roughly 1.1 million years ago. By far the strangest ocean ridge mapped, I want to know why the eruptive activity is so explosives here my guess is that the magma is probably too cold for the water associated with the volcanism to be supercritical like occurs at typical deep sea ridges under the high pressures and temperatures. This would mean the water could flash to steam as the gas and liquid phase are still distinct despite the high pressures. The most peculiar and or interesting divergent plate boundary might be the Basin and Range province and the associated Rio Grande rift Valley or if counted separately the rifting splitting away the Sierra Nevada Great Valley block away from North America. This seems likely to be a consequence of North America subducting a major mid ocean ridge and associated hot spot which has gradually torn away at the NA craton but it is a good example of how you can't readily separate divergent and convergent plate boundary behavior as they are coupled(Earth isn't getting any bigger after all). Another interesting divergent plate boundaries not covered are the Baikal rift zone and the associated pull away basin which makes the Korean peninsula as the Amur plate separates away from Eurasia. This appears to potentially be related to the flat slab subduction with melts chemically very similar to the basalts seen during the rifting of supercontinents. And as a last example to note Antarctica provides a curious example of an active rifting continent buried underneath ice which currently is acting as a lid on activity.
@vincenthalas70553 ай бұрын
Shawn. I don't understand the silence regarding my previous questions?
@vincenthalas70553 ай бұрын
Ignorant.
@victorsanchez-wg1rz3 ай бұрын
SALUDOS EKUATORIALES ANDINOS DESDE PUENGASI KITU....LA LLAKTA DE ATAHUALPA...