Appalachian Valley and Ridge example: 37.299N, 80.637W Sub-Andes example: 22.734S, 64.353W Copy and paste coordinates to Google Earth or Google Maps Terrain
GeoModels. You guys are amazing. Not sure why you are getting so few views, but I will do my best to spread the word and link back to your videos. Keep up the good work!
Thank you Gerald! I suppose we just need more Earth scientists in the world. Thanks for your interest and kind words, and please do spread the word if you enjoy the materials!
I'm in the just plain interested category and read geology for fun. I was reading about thrust belts in the western USA (Roberts Thrust, for example) and was interested in seeing a thrust belt dynamically modeled.
Thanks for checking this video out! If you don't mind telling us, are you professional, student, or just plain interested? We'd love to know who is watching!
I’m a mechanical engineer who is also interested in how land structures are formed. I perform structural simulations of complex stuff but this would be next level stuff to simulate in a computational based model.. wonder if someone has been fool enough to try an attempt to build large scale models of this. I guess with the right simplification you could get reasonable results…
Thanks TheGeoModels, nice video. I have a PhD in planetary sciences if that is what you want to know. The box is wide enough, so those materials, produce a 3D evolution (different folding lobes). Is the granular material homogeneous, and simply dye-colored? It would have been nice if you guys could have manually eroded the surface, and identify the layering on the erosion surface. Also, you could have measured the faulting angles vs time. Thanks a lot for the video !
Thanks for watching! The materials are slightly heterogeneous, with the white material being the most brittle. The newer videos on the page use highly heterogeneous materials to create flat decollements (ruclips.net/video/YtSkShrAQv0/видео.html, for example). Most of the newer videos also demonstrate erosion during shortening...this model setup is a very extreme end-member geometry, like something that occurs in the Po Basin of Italy or offshore Makran (which is thinner than what is shown here). This video has a discussion of fault angles, but most don't back-rotate signficantly here due to bed-parallel slip:ruclips.net/video/c6BzOIzT3xs/видео.html. This video shows exhumation of the model on this page, with commentary on landform development: ruclips.net/video/cf_EpEpwkTg/видео.html . A few more thrust belt-specific videos should post soon.
Hi, Thanks for the video. I have a question, in geology, because of law of superposition, each lower layers were laid several milllion years before the top one started to laid down. which means unlike this experiement, most of the layers underneath most likely concrete not flexible. do you have any experiement shows fold occurs with concrete bottom layers?
Good question...and forgive the long answer. While the confining pressure squeezing in on a rock mass does increase with depth, it doesn't necessarily make the rock "harder" and thus more likely to break like you would make a snowball "harder" and breakable by squeezing it longer and harder between your hands. Greater confining pressure or "supporting" pressure at great depth permits rock masses to experience bending and folding without wholesale breaking, shattering, etc. because these processes lead to, or require, a volume increase to occur. Thinking about rock behavior (or building concrete behavior, for that matter) at Earth's surface will mislead you, as extreme confining pressure is absent at the surface. Indeed, if you over-stress unconfined concrete quickly at Earth's surface, it cracks and breaks. If the concrete were encased at extreme pressure and elevated temperature and stressed slowly, breakage would be suppressed. Breaking/cracking/shattering increase overall rock mass volume, and this volume-increasing consequence is resisted by high confining pressure at great depth. Likewise, minerals that might experience brittle failure at lower pressure can respond to stress without breaking at great pressure (depth), temperature, and appropriate fluid environment, permitting folding without breaking despite rock masses having spent great amounts of time at great depth. Deeply buried masses can thus fold in association with stress and faulting as you see represented in these models, despite being "stronger" or more resistant to deformation than overlying sedimentary cover. The time-at-depth issue isn't so much the question as far as response to stress; burial depth and confining pressure, temperature, fluid/pore pressure, the rate at which stress is applied, and the combination of rock types present would be the main variables to look for in terms of seeking controls over large-scale structural style. Even though the sedimentary strata most of these models represent have experienced less time at depth than underlying basement, they still exhibit brittle failure and faulting, which is very different from how un-lithified sediments behave when they experience "soft-sediment" folding. The bottom line is that time at burial depth doesn't make rock "harder," and would actually render it more likely to resist brittle failure if the rock mass were being buried under an orogen as more time would allow for more heating and longer exposure to a stress field.
To take it a step further, detachment-based thrust faulting involving basement (metamorphic or igneous crustal rock below sedimentary cover) is typically drawn or interpreted using the same basic structural style as you would see in a sedimentary fold-thrust belt. The section of crust involved is thicker, and the thick thrust sheets should experience more small-scale, internal deformation, but the overall "style" doesn't look much different. The Shillong Plateau and the Rockies foreland ranges (Wind River, etc) are good examples. These structures are huge and involve many kilometers of crustal rock as well as overlying sedimentary cover, and their wavelength is enormous because they involve such a great thickness of section. That said, they are still bounded by splay faults rooting in a basal detachment (which would be a deep ductile shear zone), and splay angle is controlled by rock properties and at what angle to sigma 1 the material in question will fail. Big basement-cored structures just represent the response of confined rock to a stress field as is shown in the models here. I'll try to do a video showing interpretive style for sed rock-only and basement-involved structure that shows what I mean.
If I translate this one correctly, it could represent a rapid thickening in the wedge due to flexure or stepping of the basal detachment, or it could represent a strong rheological/mechanical transition within the wedge where a strong zone interacts with weaker materials...a thick, crystalline thrust sheet serving as backstop against a thinner and weaker sequence of foredeep sediments, perhaps. Either way, the "bulldozer" just represents a zone whose internal yield strength is greater than that of the external part of the wedge, forcing deformation to spread away from the bulldozer as the wedge grows against it. In most heavily studied and interpreted mountain ranges, the "bulldozer" as it is represented here would indeed be the thick, steeply tapering outer edges of the crystalline interior of the orogenic wedge, and the materials deformed against it would be foreland sediment sequences probably 5-7 km thick. Good question!
AWWWEESSOME
more useful than loads of structural geology lessons that I had
greetings from brazil = )
Thank you friend! Glad you found the video useful. I will try to provide some more fold-thrust content in the near future.
Wow finally got it! Thank you so much for this amazing model and informative video!
I'm a student and ths is a grat video, it really helps understand this process
Another superb job.
Thanks...this one is due for an update! Hope to have 2.0 version done within the fairly near future.
I just love watching these and am amazed at the realism. Maybe the model base could be something flexible to simulate isostasy. 😂
GeoModels. You guys are amazing. Not sure why you are getting so few views, but I will do my best to spread the word and link back to your videos. Keep up the good work!
Thank you Gerald! I suppose we just need more Earth scientists in the world. Thanks for your interest and kind words, and please do spread the word if you enjoy the materials!
I'm in the just plain interested category and read geology for fun. I was reading about thrust belts in the western USA (Roberts Thrust, for example) and was interested in seeing a thrust belt dynamically modeled.
Thanks for checking this video out! If you don't mind telling us, are you professional, student, or just plain interested? We'd love to know who is watching!
+TheGeoModels Professional Geologist
Just plain interested :-)
Nice video, the model was very helpful! I am a graduated student in planetary geology.
I’m a mechanical engineer who is also interested in how land structures are formed. I perform structural simulations of complex stuff but this would be next level stuff to simulate in a computational based model.. wonder if someone has been fool enough to try an attempt to build large scale models of this. I guess with the right simplification you could get reasonable results…
@@joecasalena8263 yep, look up finite element modeling of fold-thrust belts.
i love structural geology
That is awesome, very fun experiment!
I absolutely love this stuff
Brilliant Active Tectonics !!! Brilliant !!!
It is very useful .. thanks a lot ;)
Glad you liked it. Erosional landscape video based on this model will appear shortly.
very detailed explanation, very helpful. thanks for your work.
Thank you Dan! We hope to add a few more videos in the coming weeks. Glad you found it helpful!
Any chance you could do the mighty Karakoram range? Would be appreciated.
Thanks TheGeoModels, nice video. I have a PhD in planetary sciences if that is what you want to know. The box is wide enough, so those materials, produce a 3D evolution (different folding lobes). Is the granular material homogeneous, and simply dye-colored? It would have been nice if you guys could have manually eroded the surface, and identify the layering on the erosion surface. Also, you could have measured the faulting angles vs time. Thanks a lot for the video !
Thanks for watching! The materials are slightly heterogeneous, with the white material being the most brittle. The newer videos on the page use highly heterogeneous materials to create flat decollements (ruclips.net/video/YtSkShrAQv0/видео.html, for example). Most of the newer videos also demonstrate erosion during shortening...this model setup is a very extreme end-member geometry, like something that occurs in the Po Basin of Italy or offshore Makran (which is thinner than what is shown here). This video has a discussion of fault angles, but most don't back-rotate signficantly here due to bed-parallel slip:ruclips.net/video/c6BzOIzT3xs/видео.html. This video shows exhumation of the model on this page, with commentary on landform development: ruclips.net/video/cf_EpEpwkTg/видео.html . A few more thrust belt-specific videos should post soon.
Thank you 😀
Hi, Thanks for the video. I have a question, in geology, because of law of superposition, each lower layers were laid several milllion years before the top one started to laid down. which means unlike this experiement, most of the layers underneath most likely concrete not flexible. do you have any experiement shows fold occurs with concrete bottom layers?
Good question...and forgive the long answer. While the confining pressure squeezing in on a rock mass does increase with depth, it doesn't necessarily make the rock "harder" and thus more likely to break like you would make a snowball "harder" and breakable by squeezing it longer and harder between your hands. Greater confining pressure or "supporting" pressure at great depth permits rock masses to experience bending and folding without wholesale breaking, shattering, etc. because these processes lead to, or require, a volume increase to occur. Thinking about rock behavior (or building concrete behavior, for that matter) at Earth's surface will mislead you, as extreme confining pressure is absent at the surface. Indeed, if you over-stress unconfined concrete quickly at Earth's surface, it cracks and breaks. If the concrete were encased at extreme pressure and elevated temperature and stressed slowly, breakage would be suppressed. Breaking/cracking/shattering increase overall rock mass volume, and this volume-increasing consequence is resisted by high confining pressure at great depth. Likewise, minerals that might experience brittle failure at lower pressure can respond to stress without breaking at great pressure (depth), temperature, and appropriate fluid environment, permitting folding without breaking despite rock masses having spent great amounts of time at great depth. Deeply buried masses can thus fold in association with stress and faulting as you see represented in these models, despite being "stronger" or more resistant to deformation than overlying sedimentary cover. The time-at-depth issue isn't so much the question as far as response to stress; burial depth and confining pressure, temperature, fluid/pore pressure, the rate at which stress is applied, and the combination of rock types present would be the main variables to look for in terms of seeking controls over large-scale structural style. Even though the sedimentary strata most of these models represent have experienced less time at depth than underlying basement, they still exhibit brittle failure and faulting, which is very different from how un-lithified sediments behave when they experience "soft-sediment" folding. The bottom line is that time at burial depth doesn't make rock "harder," and would actually render it more likely to resist brittle failure if the rock mass were being buried under an orogen as more time would allow for more heating and longer exposure to a stress field.
To take it a step further, detachment-based thrust faulting involving basement (metamorphic or igneous crustal rock below sedimentary cover) is typically drawn or interpreted using the same basic structural style as you would see in a sedimentary fold-thrust belt. The section of crust involved is thicker, and the thick thrust sheets should experience more small-scale, internal deformation, but the overall "style" doesn't look much different. The Shillong Plateau and the Rockies foreland ranges (Wind River, etc) are good examples. These structures are huge and involve many kilometers of crustal rock as well as overlying sedimentary cover, and their wavelength is enormous because they involve such a great thickness of section. That said, they are still bounded by splay faults rooting in a basal detachment (which would be a deep ductile shear zone), and splay angle is controlled by rock properties and at what angle to sigma 1 the material in question will fail. Big basement-cored structures just represent the response of confined rock to a stress field as is shown in the models here. I'll try to do a video showing interpretive style for sed rock-only and basement-involved structure that shows what I mean.
Осталось найти в природе такой бульдозер.
If I translate this one correctly, it could represent a rapid thickening in the wedge due to flexure or stepping of the basal detachment, or it could represent a strong rheological/mechanical transition within the wedge where a strong zone interacts with weaker materials...a thick, crystalline thrust sheet serving as backstop against a thinner and weaker sequence of foredeep sediments, perhaps. Either way, the "bulldozer" just represents a zone whose internal yield strength is greater than that of the external part of the wedge, forcing deformation to spread away from the bulldozer as the wedge grows against it. In most heavily studied and interpreted mountain ranges, the "bulldozer" as it is represented here would indeed be the thick, steeply tapering outer edges of the crystalline interior of the orogenic wedge, and the materials deformed against it would be foreland sediment sequences probably 5-7 km thick. Good question!
studente di universita degi studi di milano，dipartimento scienze geologiche “Ardito Desio”