OneMinuteGeology
OneMinuteGeology
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Climbers Guide to Lewisian Gneiss
What gneisser way to celebrate the late summer conditions in Scotland than a brief guide to a rock type unique to the extreme North-West - Lewisian Gneiss.
The Lewisian actually contains three different rock types -
Ancient 'granitic', highly foliated and recrystallised gneiss (around 3 billion years old)
Basaltic dykes (Scourie dykes, around 2.2 Billion years old)
Younger pegmatitic granites (Laxfordian ~1.7 billion years -mstill with its original large crystal size).
These three components are intimately mixed at all length-scales, so you can get large black walls of metamorphosed basalt (with blocky weathering rather like some of the gabbro on Skye), or pristine slabs of foliated gneiss, or highly pocketed and featured climbs where smal lenses of basalt have preferentially weathered away.
What is the common feature? Extreme grippiness and flared cracks which make for some of Scotland's finest crags.
Whether you are a diff climber looking for long slab routes or into the extreme overhangs you can get when the foliation runs counter to the hillslope - Enjoy!
See also:
th-cam.com/video/7D_nWr_v4fU/w-d-xo.html
th-cam.com/video/j04A-CrdGeA/w-d-xo.html
มุมมอง: 105

วีดีโอ

Two phases of Mountain building recorded in the Cairngorms National Park
มุมมอง 28619 ชั่วโมงที่ผ่านมา
Plate tectonic convergence normally starts with subduction of oceanic crust and ends with continental collision. But there can be several phases of continental collision as small 'microcontinents' accrete onto the side of the overriding continental plate and subduction steps backwards. Here, around Grantown on Spey, we see migmatites - rocks which partially melted in the lower-crust. They were ...
Drusy Granite Pegmatite. Pass of Ballater
มุมมอง 17214 วันที่ผ่านมา
The granites of the Central Highlands are an important part of the Caledonian mountain evolution story, and over these next 3 weeks we look at some of that story. This week - granite pegmatite demonstrates that the Cairngorm granite massif originated by melting in th elower crust. In order to grow pods of pegmatite (very coarse grained granite) in the middle of mor normal granite water must hav...
When rocks can't take the pressure - Razors Edge, Pass of Ballater
มุมมอง 45321 วันที่ผ่านมา
Rock is heavy stuff- with a density around 2.5-3.5 tons per cubic metre. That is fine when the weight of the rock is supported over a large area, but in granular materials all the load is concentrated at the contact between the grains. This climb follows some very large stacked blocks (grains) and the one at the bottom is supporting all the others on a very small area of its corner, resulting i...
These rocks contain a Golden Spike! Dob's Linn
มุมมอง 16628 วันที่ผ่านมา
Geological time is measured by changes in the rocks - this might be radioactive decay for absolute dating, but what is there aren't sufficient radioactive elements, or the rock is made of grains derived from older rocks, as is the case for most sediments? Relative dating uses changes in the fossil record as the creatures which are preserved evolve through time. A good index fossil is one which ...
Lapilli Tuff; Bochlwyd path
มุมมอง 102หลายเดือนก่อน
Large volcanoic eruptions (Particularly Plinian style eruptions) can generate a lot of static electricity. Each time a rock fractures charge is separated on its surface, so when you convert the entire contents of a magma chamber into ash - that is a lot of charge. Hence all the lightning associated with volcanic eruptions. This charge will also make the ash particles stick together - particular...
There is a fault in this climb: Llanberis Slate
มุมมอง 174หลายเดือนก่อน
Slate climbing is all about good small edges and tenuous smears. But Gadaffi Duck in the Looning the Tube sector of Australia Hole has a particularly slippery right wall for the start. The green mineral lining the right wall is fibrous epidote, and all the fibres point straight down, giving you nothing for your feet. This is a fault plane and the fibres align in the direction of motion of the f...
These three minerals define the Pressure-Temperature-time path of metamorphism.
มุมมอง 164หลายเดือนก่อน
The Al2SiO5 polymorphs are very useful metamorphic indicator minerals for mudstones (metapelites). These rocks are silica saturated and alumina rich meaning that these aluminoslilcates can be common minerals in metamorphic rocks. Each different crystal structure is stable at different pressures (P) and temperatures (T), with Kyanite stable at high pressure, Sillimanite stable at high temperatur...
Highland Boundary Fault at Stonehaven
มุมมอง 549หลายเดือนก่อน
The highland boundary fault is one of the major structural lineations which divides Scotland into 4 major tectonic regions. The HBF is a normal fault on th eNorthern edge of the Midland Valley, with the Highlands to the North. The exposure on the coast here at Stonehaven is particularly good for seeing the structure of the fault, with increasing damage and fracturing of the rocks on either side...
Secondary Copper Deposits, Geevor Mine.
มุมมอง 4672 หลายเดือนก่อน
Last week we looked at iron and manganese mineralisation produced by reaction of reduced acidic water with air. This week we go mre extreme, looking at acid mine drainage, in this case at Geevor tin mine in Cornwall. Copper was present along with the tin, as copper sulphides. When exposed to mine water this insoluble copper sulphide reacts to make copper sulphate solution. When this solution is...
Manganese-Iron oxides at Greenock Cut.
มุมมอง 3162 หลายเดือนก่อน
This week and next we will look at secondary mineralisation which forms when metal-rich water is exposed to air. Typically the solubility of transition metals increases as water becomes more acidic and more reduced. Next week wee will lok at a rather pretty example of acid mine drainage, but this week we are looking at an entirely natural example: iron-magnagese oxides. The carboniferous sandst...
Ecton Copper Mine, Derbyshire
มุมมอง 2072 หลายเดือนก่อน
Derbyshire was a major lead mining region for several centuries. The lead and associated mineralisation were sourced from metamorphic fluids during the Variscan Orogeny and squeezed up into the limestones of the Derbyshire basin to form a Mississippi-Valley-Type lead-zinc ore deposit. So the copper at Ecton is unexpected. We don't understand the origin of the Ecton copper -which was at one time...
Off-fault deformation below the Moine Thrust. Ben Arnaboll.
มุมมอง 2112 หลายเดือนก่อน
We often think as rocks deforming in either a brittle or a ductile manner, but the truth is much more complex than that, with ductile-like behaviour occuring very close to active faults and even on active faults during some parts of the earthquake cycle. Here in the Quartzite at Ben Arnaboll (about 30 m below the Arnaboll thrust and probably only 100 m or so below where the Moine would have bee...
Hydrothermal alteration in Lochnagar: Weathering and semi-precious minerals
มุมมอง 3733 หลายเดือนก่อน
Granitic magma contains a LOT of water (up to 5 wt% - that is about 1 in 4 of the atoms in the magma being related to water), but solid granite doesnt contain many hydrous minerals. That means as the magma crystallises water is lost, resulting in extensive hydrothermal (hot and wet) aleration and veining of the surrounding country rocks and any already crystallised granite. Here in Lochnagar we...
Scotland's flash-flood deserts. Old Red Sandstone on Kerrera.
มุมมอง 5773 หลายเดือนก่อน
They say the past is a different country - but the deep geological past is often more like a different planet! During the Devonian, around 400 million years ago, Europe and North America were joined and a vast inland desert covered much of what is now Canada and Northern Europe. As the mountains produced during the Caledonian and Acadian orogenies weathered away the provided plenty of clastic m...
Structurally controlled mineralisation. Ecton Mine, Derbyshire
มุมมอง 1983 หลายเดือนก่อน
Structurally controlled mineralisation. Ecton Mine, Derbyshire
Granite emplacement 2: Two generations of dyke at Porthmeor
มุมมอง 1653 หลายเดือนก่อน
Granite emplacement 2: Two generations of dyke at Porthmeor
Granite emplacement 1: Megiliggar Rocks
มุมมอง 5223 หลายเดือนก่อน
Granite emplacement 1: Megiliggar Rocks
Dow crag rhyolite. Red-hot rocks.
มุมมอง 5004 หลายเดือนก่อน
Dow crag rhyolite. Red-hot rocks.
Poison-loving plants:Magpie Mine metallophytes
มุมมอง 1764 หลายเดือนก่อน
Poison-loving plants:Magpie Mine metallophytes
300 Million missing years. Isle of Kerrera.
มุมมอง 6444 หลายเดือนก่อน
300 Million missing years. Isle of Kerrera.
Extreme Folding of sediments. Isle of Kerrera
มุมมอง 4594 หลายเดือนก่อน
Extreme Folding of sediments. Isle of Kerrera
Glacial Raised Reach, Isle of Kerrera
มุมมอง 4365 หลายเดือนก่อน
Glacial Raised Reach, Isle of Kerrera
Why are the North Face of the Ben and Carn Mor Dearg so different?
มุมมอง 4275 หลายเดือนก่อน
Why are the North Face of the Ben and Carn Mor Dearg so different?
Gypsum Mylonite in Barranco Salada
มุมมอง 3075 หลายเดือนก่อน
Gypsum Mylonite in Barranco Salada
Dynamic recrystallization of gypsum porphyroblasts in Barranco Salada
มุมมอง 2005 หลายเดือนก่อน
Dynamic recrystallization of gypsum porphyroblasts in Barranco Salada
From Ocean Basin to Mountain and Back Again. A Potted History of Spain's Southern Mountains.
มุมมอง 3095 หลายเดือนก่อน
From Ocean Basin to Mountain and Back Again. A Potted History of Spain's Southern Mountains.
Garnet Volcano and Atoll; Cerro del Hoyazo
มุมมอง 2845 หลายเดือนก่อน
Garnet Volcano and Atoll; Cerro del Hoyazo
Active Normal Faulting, Tabernas (S Spain)
มุมมอง 2235 หลายเดือนก่อน
Active Normal Faulting, Tabernas (S Spain)
Subaqueous Ash Deposit, Walna Scar Road
มุมมอง 1886 หลายเดือนก่อน
Subaqueous Ash Deposit, Walna Scar Road

ความคิดเห็น

  • @mikelong9638
    @mikelong9638 23 ชั่วโมงที่ผ่านมา

    Nice video Doc! Always nice to see someone enjoying their passions.

    • @OneMinuteGeology
      @OneMinuteGeology 6 นาทีที่ผ่านมา

      It has been such good weather in the North West in mid-September it would have been a crime not to get out!

  • @Crusty_Camper
    @Crusty_Camper 8 วันที่ผ่านมา

    Even with a basic knowledge of geology, I would miss so much at this kind of exposure without the guidance of a real expert.

  • @johnh539
    @johnh539 8 วันที่ผ่านมา

    Concise and fascinating . For one thig I did not realise quarts came from melted Granite.

  • @briandwi2504
    @briandwi2504 8 วันที่ผ่านมา

    Fascinating, as always. Thanks!

  • @geoatavist6880
    @geoatavist6880 11 วันที่ผ่านมา

    Just had your channel recommended by a fellow Birkbeck Geology alumni. Great videos.

    • @OneMinuteGeology
      @OneMinuteGeology 10 วันที่ผ่านมา

      So glad you like them. Do spread the word!

  • @briandwi2504
    @briandwi2504 12 วันที่ผ่านมา

    Love your videos. Really interesting. Thanks!

    • @OneMinuteGeology
      @OneMinuteGeology 11 วันที่ผ่านมา

      Thank you! Glad you like them.

  • @jncolligan1
    @jncolligan1 14 วันที่ผ่านมา

    Wow.. that was nuanced! Nice Find! Love the chart!

    • @OneMinuteGeology
      @OneMinuteGeology 14 วันที่ผ่านมา

      Hey Joe, good to hear from you. Granites are soooo complex. This is the first in three granite/crustal evolution vids where, hopefully the concepts and rocks will start to build into a coherent picture. But some of this is still being actively researched and our understanding will probably evolve over the coming years. It is great that Scotland's geology is still the source of new ideas and discoveries despite being one of the (if not the-) longest-studied regions in the world.

    • @jncolligan1
      @jncolligan1 13 วันที่ผ่านมา

      @@OneMinuteGeology yeah… I’m slowly getting my head around Granite and it’s igneous alter-ego Gabbro! It’s crazy that you can see mounts built with both of this right next to each other on the Isle of Skye… I think it was the Luib scenic look-out that you cans see the black gabbros right next to that red granite hilltops?

    • @OneMinuteGeology
      @OneMinuteGeology 13 วันที่ผ่านมา

      @@jncolligan1 yes, the granite-gabbro association is a striking one. Skye is a very good example of how large basic intrusions can heat the crust sufficiently to partially melt it, making granites. These are A-type granites, which are lower in water than the mountain-building S-type granites and so I expect will be less likely to contain pegmatites (not that I have looked hard for pegmatite in the Red Cuillin). You get A-type granites associated with mantle plumes interacting with continental crust - on Skye, associated with the Columbia River basalts and Yellowstone, to name a few. There is a great itinerary into Camasunary Bay where you can see how gabbro dykes have heated the Torridon sandstone sufficiently to melt it. Let’s do it sometime.

  • @TokyoNightGirlLofi
    @TokyoNightGirlLofi 21 วันที่ผ่านมา

    Nice👍💜

  • @mikelong9638
    @mikelong9638 21 วันที่ผ่านมา

    Be careful Doc!

  • @lineinthesand663
    @lineinthesand663 22 วันที่ผ่านมา

    Visualising stress as flow/flux lines is useful. Fortunately, stress did not become strain the one minute you were there. All the best.

    • @OneMinuteGeology
      @OneMinuteGeology 21 วันที่ผ่านมา

      You didn't see me climbing!

    • @lineinthesand663
      @lineinthesand663 21 วันที่ผ่านมา

      @@OneMinuteGeology If that lot fell, you would be oozing, not climbing. It looks just like a deadfall trap.

  • @mdc123-v2v
    @mdc123-v2v 29 วันที่ผ่านมา

    Good to see you in the Borders! I know we don't have the most exciting geology in the country, but what we do have is pretty special imo!

    • @mikelong9638
      @mikelong9638 29 วันที่ผ่านมา

      I've been watching these from the USA for a couple of years. You have great geology over there. It's just that it rains all the time😂

    • @OneMinuteGeology
      @OneMinuteGeology 28 วันที่ผ่านมา

      Yes, there are loads of classic sites. The problem is we are normally on our way somewhere else.

    • @OneMinuteGeology
      @OneMinuteGeology 28 วันที่ผ่านมา

      @@mikelong9638 true, not quite always. But at least we don’t have rattlers.

    • @mikelong9638
      @mikelong9638 28 วันที่ผ่านมา

      @@OneMinuteGeology You had to mention that!

  • @hypnoshu
    @hypnoshu หลายเดือนก่อน

    Take me to the fields plz😁

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      I do offer guided geology days in the UK. Are you UK based?

  • @mikelong9638
    @mikelong9638 หลายเดือนก่อน

    Are these slickensides, or something a litlle different?

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      They are a type of slickenside (or in modern terminology fault-plane lineations - I prefer the old slickenside). There are two main types of FPL - aligned crystals and gouge-type FPLs. These are aligned crystals, which have the sense of roughness as described here. The gouge-type FPLs have the opposite sense of roughness (and since slickenside means 'polished surface' in the original German) they are possibly 'true slickensides'. So you have to be a little careful when determining fault kinemantics from these features. As always, it is a bit more complex....

  • @GusRojas-s1h
    @GusRojas-s1h หลายเดือนก่อน

    Thanks ,Doctor

    • @GusRojas-s1h
      @GusRojas-s1h หลายเดือนก่อน

      Thank you, for today lesson.

  • @GusRojas-s1h
    @GusRojas-s1h หลายเดือนก่อน

    The profe. With the yellow shirt, nice. Thanks

  • @GusRojas-s1h
    @GusRojas-s1h หลายเดือนก่อน

    Thank you, professor

  • @sharondobson4764
    @sharondobson4764 หลายเดือนก่อน

    "bluey"??

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      Yes. Technical term meaning 'with hints of blue colour', as in 'bluey-grey'.

  • @mikelong9638
    @mikelong9638 หลายเดือนก่อน

    Thanks Doc.

  • @lcfcking9104
    @lcfcking9104 หลายเดือนก่อน

    I have found a perfect ball and it has a egg texture..it's insides have chalk look to it I'm putting a video on my account for anyone who has information on it

  • @Bacrenfencing
    @Bacrenfencing หลายเดือนก่อน

    I fish off the Garron point by boat, some great Cod fishing there !

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      Hah, Great! I guess the seafloor is quite rugged off the Point - do Cod like nooks to hide in or are they more open water fish? I remember fishing with my uncle out of Carnoustie as a lad and one side of the boat being super abundant for a spell of half an hour or so, but the other side catching nothing. We assumed the line had found a crevice in the seafloor. But I don't remember what fish we caught.

  • @quakekatut8641
    @quakekatut8641 หลายเดือนก่อน

    Thanks for another great video fieldtrip! I'm from the Great Lakes region (USA) ... still I find GB geology fascinating. My mother is from Scotland, so maybe there's some geo-gene connection! 🙂

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      Cheers, Glad you liked it!

  • @susanbone3634
    @susanbone3634 หลายเดือนก่อน

    So interesting to find out about this; thank you for making these videos, your observations are always a treat

  • @mikelong9638
    @mikelong9638 หลายเดือนก่อน

    Good morning from the USA. Always good to get a short geology lesson with my first cup of coffee! Thanks for making this.

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      Good afternoon from Japan, via China! Watch this space for a few non-UK vids in the coming months

  • @alanmurdock4319
    @alanmurdock4319 หลายเดือนก่อน

    Is 300 million years ago when it collided with North America before breaking apart again?

    • @OneMinuteGeology
      @OneMinuteGeology หลายเดือนก่อน

      The closure of the Iapetus ocean started around 450 Milion years and by 300 million the collision was pretty much over - but yes, that was the event which brought N America and Eurasia together as part of building the Pangea supercontinent.

  • @melodybarbour3218
    @melodybarbour3218 หลายเดือนก่อน

    The biblical flood is what caused chalk beds.

  • @ericclayton6287
    @ericclayton6287 2 หลายเดือนก่อน

    Those primary oxidation zones are common and deep in arid regions, are they shallow in Cornwall and Britain in general?

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      yes they are - often at the surface.

  • @mrsironted
    @mrsironted 2 หลายเดือนก่อน

    🎉 we got the Greenock cut rust film 😁

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      the films of the cut cut together well. Hope you are all well as well.

  • @mikelong9638
    @mikelong9638 2 หลายเดือนก่อน

    Very interesting video Doctor. Please keep these coming.

  • @williamcarroll7909
    @williamcarroll7909 2 หลายเดือนก่อน

    Thank you. For years I have walked along a river bank banks wondered why I found rust deposits as you show in the video. The river in question cuts through Lower Devonian Sandstone, which is overlain by peaty soil. Now I understand what is going on

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      Ah yes, the Old Red Sandstone has plenty of iron in it.

  • @rohan_singh_bhadoriya
    @rohan_singh_bhadoriya 2 หลายเดือนก่อน

    I don't know much about these mines but sir be safe..❤

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      Thanks for your concern. I was with the mine custodian so in very safe hands.

  • @SB-qm5wg
    @SB-qm5wg 2 หลายเดือนก่อน

    curious case of crystalisation

  • @rohan_singh_bhadoriya
    @rohan_singh_bhadoriya 2 หลายเดือนก่อน

    this was of great help as pictures in the books are not that much comprehensible

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      SO glad you liked it. Thanks.

  • @karinhoferapostolidis5336
    @karinhoferapostolidis5336 2 หลายเดือนก่อน

    All the nice geo-insitu-classes! Nice Dave! 👊🏻💥 The pink chinchilla brings all the style to the video! Greetings from Lausanne! 😊🙏🏻🌻

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      😀😀😀 Hope you are enjoying the mountains!

  • @deanhampton1527
    @deanhampton1527 2 หลายเดือนก่อน

    Very useful, appreciate the little animation to understand how volcanic plugs are formed.

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      Thank you so much. Glad you liked it.

  • @rebbysharp2778
    @rebbysharp2778 2 หลายเดือนก่อน

    Skolithos? We have tons here in blue ridge area of virginia. I enjoy each and every one of your clips, thank you.

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      Yes, While Skolithos is a generic term for vertical burrows which covers a wide range of geological time, I guess yours are similar age in rocks deformed by the Appalacian Orogeny? Glad you like the vids.

  • @eliasrugen659
    @eliasrugen659 2 หลายเดือนก่อน

    Great filming

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      It took a bit of explaining but the cameraman got the idea in the end

  • @mikelong9638
    @mikelong9638 2 หลายเดือนก่อน

    Thanks doctor. If there are trace fossils of "worm holes?" that would somewhat date this? When?

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      These trace fossils aren’t great for dating rocks as they occur across a wide range of time. But in this case it is their very first appearance at the start of the Cambrian. Around 550 million years ago.

  • @BeverleyW
    @BeverleyW 2 หลายเดือนก่อน

    How high is that region above current sea level?

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      The peaks around here are around 1100 m altitude here on the ridge we are around 800 m.

  • @BeverleyW
    @BeverleyW 2 หลายเดือนก่อน

    That's really interesting about the milky quartz formation. Would you say this is similar to how opal is formed?

    • @OneMinuteGeology
      @OneMinuteGeology 2 หลายเดือนก่อน

      Thanks for the question.. as I understand it opal forms during diagenesis - as sediments consolidate to turn into rock. That occurs at really low pressures and temperatures 100s of m to a few km of burial depth. This milky quartz is metamorphic, requiring burial to at least 10 km depth - probably much more.

  • @lineinthesand663
    @lineinthesand663 3 หลายเดือนก่อน

    Ta the video. Without water, the soup will not cook. Griesens are some of the most fascinating aspects of granites. All the best from Namibia.

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Cheers. I was just at Cligga Head a couple of weeks back where there are some great Tin-Tungsten greisen veins. You saw my old vid on Cligga?

    • @lineinthesand663
      @lineinthesand663 3 หลายเดือนก่อน

      @@OneMinuteGeology Thanks. I'll catch up soon. We've some splendid examples of Sn/W/Ta mineralisation here as well.

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      @@lineinthesand663 th-cam.com/video/Ep4nJhhvCvg/w-d-xo.html

    • @lineinthesand663
      @lineinthesand663 3 หลายเดือนก่อน

      @@OneMinuteGeology Remiss of me. So I had seen it and commented.

  • @mikelong9638
    @mikelong9638 3 หลายเดือนก่อน

    Thanks Doctor. Safe travels.

  • @eliasrugen659
    @eliasrugen659 3 หลายเดือนก่อน

    Best video on the channel

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      I’m sure Joe will be chuffed.

  • @willmuirr
    @willmuirr 3 หลายเดือนก่อน

    Love this little vid. Loads of learning available

  • @SB-qm5wg
    @SB-qm5wg 3 หลายเดือนก่อน

    Scotland has seen a lot of changes.

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Yes indeed! The geological past stretches back a looong way.

  • @BillyBobDingo1971
    @BillyBobDingo1971 3 หลายเดือนก่อน

    Very cool. Thanks.

  • @Valearsa
    @Valearsa 3 หลายเดือนก่อน

    Does this means that nappe always formed from previous thrust folds? I mean does the existence of thrust folds is a requirements before another compressional stress is given to form nappe?

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Hi, I'm not entirely sure I understand your question. But I think the answer is (probably) maybe not if I am interpreting it correctly. The model ends up forming these fold systems sequentially, but it is just a very simple model with totally different flow physics and boundary conditions from the Earth. In real world systems you can get several fold and fault systems developing concurrently (although strain weakening rheologies tends to cause one fault to dominate at any given time, this isn't so true for folding). Once you are into fully ductile regimes (say lower crust or even the mantle in somewhere like Ronda) there is a continuum between distributed ("fold-like") and locallised ("fault-like") deformation, but you still produce structures with a nappe-like geometry. Does that help?

  • @chelseadavies8665
    @chelseadavies8665 3 หลายเดือนก่อน

    Thanks for the explanation.

  • @sgs9351
    @sgs9351 3 หลายเดือนก่อน

    Where is this?

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Elton mine in Derbyshire, England

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Ecton mine, not Elton mine - autocorrect strikes again

    • @sgs9351
      @sgs9351 3 หลายเดือนก่อน

      Thanks sir

  • @GeologyNick
    @GeologyNick 3 หลายเดือนก่อน

    Very well done! Thank you.

    • @OneMinuteGeology
      @OneMinuteGeology 3 หลายเดือนก่อน

      Thank you! Glad you like it.

  • @SB-qm5wg
    @SB-qm5wg 3 หลายเดือนก่อน

    perfect example