Crustal shear zones at outcrop - a visit to the northern Moine
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- Опубліковано 27 сер 2024
- Part of The Shear Zone Channel. Join Rob as he visits a wonderful natural section across a crustal scale shear zone in northern Scotland. See how the apparent simplicity of the structure hides a secret - folding, that is sheared around - locally creating tube-like structures - sheath folds.
#NC500 #geology #tectonic #scotland #geopark
Thank you, Sir. You gave me a good time with extraordinary site and the dream to have a look by myself.
It's certainly a great place to visit - a bit of a hidden gem. But the outcrops are very accessible - once you get to the far north of the Scottish mainland...
@@robbutler2095 🙂
Amazing sheat fold i Never seen this.thank you.
Yes - it is rather good. Lots more in the Moine around these localities.
Your contributions and love towards geology, are so much worth-praising and worth commending ...💕
Glad you enjoyed the video!
Great work. Thanks for sharing your knowledge with us. Always learn new stuff from Dr. Rob.
Thanks - glad these short videos are helpful...
Would you share with us some naturally fractured reservoir (Nelson) lectures
Enjoyed this video, such crustal deformation.Since this occurs in a ductile environment, what depths and temperatures are necessary to accomplish this metamorphism? Silica and Feldspars are the first to melt? Is the age of this shear zone occurred during the “Caledonian Orogeny”?
Thanks for all of the quality videos and lectures, great job.
Thanks for the questions Mathew. The rocks in this part of the Moine probably deformed at about 500 degrees C and around 18-20 km down in the crust. They were carried up on slightly younger structures (including the Moine Thrust) with the overburden eroding as it moved (just like along the edge of the Himalayas today). These structures are part of the so-called Scandia part of the Caledonian orogeny - around 430-440 million years ago here.
Thank you for your field teaching! I have never been there but usually read materials about Moine Thurst. Is this ductile shear zones and mylonites belonging to the thick-skinned type of thrust? Is there normal shear zone determined in any sections here, which can be formed in extensional environment of a thickening crust?
These shear zones are top WNW - so thrust sense. Probably detachment-dominated, flooring into the Moine Thrust.
Hello Prof Butler,
I have taken numerous courses on Structural Geology and have always enjoyed picturing hundreds of square miles of real estate break and climb on top of itself, but I have always struggled to picture the whole profile down into the mantle. It would be very informative to see the changes in deformation types with depth, within this profile, during a frontal convergent margin collision.
I can picture the brittle top of the crust inversely faulting and I can picture the ductile bottom of the crust shearing and flowing, but I'm sure there is more detail than this. For example, is there such a thing as a "transition" zone between the ductile and brittle zones? and how would that zone deform?
Thank you and congratulations on your informative channel, I look forward to watching your future videos.
Hi - thanks for the comments and question. What you're after are examples of structures that cross the so-called "brittle-ductile transition" (see video here about the strength of continental lithosphere (how strong are plates?). As for field examples, the array of structures in the Moine Thrust Belt does it... (videos here on South Eriboll vs Arnaboll Thrust)... but the finest example anywhere - in my view - is associated with what we called the Liachar Thrust, on the flanks of Nanga Parbat (Pakistan Himalayas). Check out the video (and link) on Making the Building of Nanga Parbat... Hope they fit the bill.
@@robbutler2095 thank you very much, I watched the How Strong are Plates? video and it was incredibly informing.