Paleomagnetism and plate tectonics

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Callan Bentley

10 жыл бұрын

A response to a student question about magnetic reversals

Пікірлер: 45

@artysanmobile Жыл бұрын

Callan, you have a teacher’s manner in your voice which I find ideal. Looking forward to more knowledge from you.

@shubhamrajput8449 3 жыл бұрын

I dont have any exam of geography nor i am good at it. But found it very simple only because of your great art of explaining things in such simple manner

@Vishnoipraveen 7 ай бұрын

9 year back and still relevant thankyou Callan from India cheers

@mrfranksan 4 жыл бұрын

Once again an outstanding progression of the ideas. Puzzle pieces flying into place from many jumbled memories. Thanks.

@Autonomyz2 8 жыл бұрын

Thanks a million times! I have the exam and this made me more understand in Paleomagnetism.

@islammokhtar2926 3 жыл бұрын

a high-schooler from Egypt wants to thank you extremely for your effort exerted in that video, really like words can't help me to thank you enough for this clarifying presentation. Thanks sent from the country of Mo. salah, Giza pyramids ,and Pharaohs

@OmarMagdiii 4 ай бұрын

تنشيط السياحه XD

@wonderwang1585 3 жыл бұрын

Thanks for solving the huge quiz of mag reversal

@Rebeldoug 6 жыл бұрын

This really pulls together all my questions as to how Scotese got all those tectonic plates moving around. I’m sure there’s other factors but this information has got to be a big one.

@fariemadondo8898 9 жыл бұрын

Geophysics exam in a few days .It's 2 in the morning and still can't grasp the idea of remanent magnetisation.I honestly can not thank you enough for this video..textbooks always complicate things sigh ..

@Ellensburg44 4 жыл бұрын

Super excellent!

@Moon-qy1sn 5 ай бұрын

this was such an interesting video! made it extremely fun to learn geology thank you!

@Satyendra-xe9fe Жыл бұрын

Very well explained! Thank You

@callanbentley 9 жыл бұрын

Rebecca, I know the feeling. I like that feeling of insignificance. I find it liberating. Do what you love with life, for it matters principally to you alone. Carpe diem!

@rebeccaryan8262 9 жыл бұрын

Thank you. Am studying Physical Geology. This video really clarifies topic. Love Geology, but on one level it makes me feel very small and insignificant. Intriguing and depressing at the same time. : )

@megha971 3 жыл бұрын

Thank you so much! I am strudying studying structure of the earth just out of curiosity and this really helps.

@Conqurer26 Жыл бұрын

बहुत सुंदर व्याख्या आपके द्वारा की गई है सर

@wonderwagon3304 6 жыл бұрын

Wow, what a fantastic presentation! Thank you so much.

@reshmatalk123 6 жыл бұрын

Brilliant explanation just wow thanks alot sir

@asmasadeghi75 Жыл бұрын

thank you that was really helpful

@george5401 5 ай бұрын

God bless you man.

@animeshmondal7698 6 жыл бұрын

Excellent.

@ltaufani 6 жыл бұрын

Excellent presentation! Thanks for making it. Btw, is there any chance to get this slide pictures? Many thanks.

@johanbtheman Жыл бұрын

Very very interesting! Can these spots of decreased magnetic fields be related to certain parts of the ice sheets melting?

@abdelrahmanmustafa1633 7 ай бұрын

Science is fun!

@DonnaChassie Жыл бұрын

Thank You.

@luvinthejazz 8 жыл бұрын

Thank you Mr. Bentley, excellent presentation. How quickly are the reversals accomplished? Are they instantaneous, span several days or several years?

@faisalmuhammad5364 8 жыл бұрын

can you please upload a video which tells us why seismic waves travel in the interior splits into two waves( S& P waves)?? thanks

@mikaelwerner1 7 ай бұрын

A remark about your explanation from 9:10 As you know a magnetic pole is where the inclination is 90 degrees. The magnetic field lines, along which a compass needle points, is not (at every given point) a straight line (along the surface of the earth) to the northern magnetic pole. I understand it is a well established pedagogical practice to assert that declination is the angle between the northern magnetic pole and true north, just for the sake of simplicity of explanation, but that does not prevent it from being somewhat inaccurate. The local magnetic field lines are, as you must know, in fact quite chaotic and does not point in a perfect arc straight to the northern magnetic pole. Anyone can easily verify that by reading the charts of the WMM based on reccurring systematic surveys and provided by NCEI. So you cannot pinpoint the historical exact location of the northern magnetic pole by studying sea sediments, you can however identify a local change of direction and also a shift of polarity, which is what I think you actually wanted to explain here.

@2of238 4 жыл бұрын

Thanks

@toddwheatley-dr-know3964 5 жыл бұрын

Given its broad application, everyone should understand GEOLOGY - therefore this video has been indexed and a link added by DR-KNOW / iq-2k Information Services - roughly 650 videos have indexed for this series

@operaflute 10 ай бұрын

So this process of tracking the movement of continents using declination and inclination is what Brenner and Fu used to track the speed of the movement of Pilbara Craton?

@callanbentley 10 ай бұрын

Not familiar with that particular study. Link?

@operaflute 10 ай бұрын

No idea why my reply won't stick. Trying again today! I read mention of it in "A Brief History of Earth" by Andrew H. Knoll. Not a geologist by any stretch, it sent me running for more info. (Your point about magnetic inclination was the missing piece of the puzzle in my head.) Look for "Paleomagnetic Evidence for Modern-like Plate Motion Velocities at 3.2 Ga," by Brenner et. al. (Not posting link just in case that was the problem with my reply not sticking.)

@gpietra 6 жыл бұрын

Do the reversal of the magnetic pole invalidates the assumption of the movement of the continents based on the apparent polar wander path? I mean...since, after paleomagnetic measurements in ancient rocks, we said: "it's not the North magnetic pole which is moving but the continents", how count in the equation the polar reversal phenomenon?

@callanbentley 6 жыл бұрын

"gpt" - This is the rare excellent question on a KZfaq video. Short version: no. Longer version: the polarity is binary: either north-flowing or south-flowing. So the angle of inclination would be identical, even if the arrow of declination is reversed. You can still track where the pole is relative to a given site with the inclination data alone. That said, there is a bit of wobble in the pole's exact position. It's not exactly at the geographic pole, and it doesn't stay put, but moves over time. The key is that that overall motion is relatively limited in extent - it's called "secular variation," and it's analogous to the flicker of a candle flame. On average, a candle flame points upward, and even if there's a slight breeze, it wobbles a bit, but then returns to upright. Similarly (we think), the secular variation in the position of the Earth's magnetic poles also wobbles around a little bit, but always keeps to somewhere close to the geographic north pole, and hence on average can be useful for things like calculating apparent polar wander paths.

@gpietra 6 жыл бұрын

Callan Bentley Makes perfectly sense! Thanks for your answer

@mrfranksan 4 жыл бұрын

@@callanbentley . . . but the drifting of the poles and the presence of less coherent magnetic field fluctuations do complicate the localization, right? My understanding is there's an accelerating drift of the field since about 1990 that is poorly understood.

@callanbentley 4 жыл бұрын

@@mrfranksan Post 1990 'acceleration' is a short timescale phenomenon - a slight change in rate of movement of the pole that is entirely within our understanding of the general dynamic state of the field, and operating much more rapidly than plate movements.

@SolaceEasy 4 жыл бұрын

Donut shapes have holes. Maybe it looks closer to a bagel that's so fat it has no hole.

@rajdeepawasthi3678 Жыл бұрын

Great lecture but diagramatical representation is wrong . Magnetic field line arise from north pole and sink into south pole outside the magnet which you have showed opposite.

@THEHULK007MYTHICALLY 5 ай бұрын

The earth's magnet is reverse. That's why the north of a magnet hung by a string points to the geographic north of the earth because the earths magnetic south pole is there.

@nipunadeshan2424 4 жыл бұрын

tomorrow is the exam covering full syllables am i legend...XD

@Dragrath1 6 жыл бұрын

You should have mentioned that the south magnetic pole is really a magnetic north pole at least with respect to the physics and a bar magnet comparison the terminology threw me off here