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Steffen Büttner - Geology clips
South Africa
Registrace 30. 03. 2020
Hi all
This channel contains undergraduate courses in Structural Geology and Tectonics (BSc 1 to BSc 3) at Rhodes University (South Africa). There are also a few lectures on introductory geology that I present in a bridging course at a level between high school and university (our Science Extended Studies Program - SESP).
Most of our graduates leave with a 3rd or 4th year (BSc/BSc Honours) degree, seeking industry employment, few carry on with an MSc, and hardly anyone does PhDs. Hence, the BSc courses focus on matters that I deem relevant for work in the minerals industry rather than in senior postgraduate research. Accordingly, if you look for material on continuum mechanics or strain analysis, or modern microstructural analysis, you will not find much. I try to expose my students to content that might help them to make sense of features they see in the field and understand their formation.
Enjoy,
Steffen
This channel contains undergraduate courses in Structural Geology and Tectonics (BSc 1 to BSc 3) at Rhodes University (South Africa). There are also a few lectures on introductory geology that I present in a bridging course at a level between high school and university (our Science Extended Studies Program - SESP).
Most of our graduates leave with a 3rd or 4th year (BSc/BSc Honours) degree, seeking industry employment, few carry on with an MSc, and hardly anyone does PhDs. Hence, the BSc courses focus on matters that I deem relevant for work in the minerals industry rather than in senior postgraduate research. Accordingly, if you look for material on continuum mechanics or strain analysis, or modern microstructural analysis, you will not find much. I try to expose my students to content that might help them to make sense of features they see in the field and understand their formation.
Enjoy,
Steffen
Active plate margins and back-arc tectonics
This video describes the principal elements of active plate margins and how they form. It also contains information on the various types of back-arcs, tectonic switching and the factors that control the transition from extensional to stable or contractional back-arc mobile belts.
zhlédnutí: 208
Video
Continent collision
zhlédnutí 105Před měsícem
This video describes the principal processes during continent-continent collision and escape tectonics using the example of the Alps and the Himalayas at 2nd year university level.
Duplexes, flat ramp structures and imbricate fans
zhlédnutí 141Před měsícem
Description of how and why common contractional structures form
Folds and folding video
zhlédnutí 163Před měsícem
An overview of folds, folding mechanisms and folds of different order (parasitic folds)
Rifts and continental breakup
zhlédnutí 142Před měsícem
This video describes the various ways in which continental rifts form and develop to oceanic basins and passive continental margins.
Extensional structures in rifts
zhlédnutí 191Před 2 měsíci
First part of a lecture on rifts and continental breakup. Common structures in rift zones.
Anderson's Fault Theory
zhlédnutí 177Před 2 měsíci
This video explains why dip-slip and strike-slip faults are so common (and how oblique-slip faults may form)
Pre-existing fractures in the Mohr stress diagram
zhlédnutí 64Před 2 měsíci
How do fractures affect the shear strength of rocks?
Variable fluid pressures and vein formation in the Mohr stress diagram
zhlédnutí 70Před 2 měsíci
How fluids change the mechanical stability of rocks
The basics of the Mohr stress diagram
zhlédnutí 103Před 2 měsíci
The basics of the Mohr stress diagram including the four failure envelopes
Fractures and stresses in rocks
zhlédnutí 79Před 2 měsíci
Background information on different fracture types, veins and stresses that form them
The fracturing Process GLG2 Chapter 1
zhlédnutí 209Před 2 měsíci
2nd year Geology level video on how fractures and faults form.
The Mica Group - mineral structure, composition and classification
zhlédnutí 1,1KPřed rokem
Introduction to the chemistry and structure of mica minerals
Clickable attachment link icons in Adobe PDF files
zhlédnutí 7KPřed 2 lety
How can I create icons in PDF documents that link to attached files?
Fold analysis using Rick Allmendinger's Stereonet 11
zhlédnutí 13KPřed 3 lety
Fold analysis using Rick Allmendinger's Stereonet 11
The evolution of the Cape Fold Belt (South Africa)
zhlédnutí 2KPřed 3 lety
The evolution of the Cape Fold Belt (South Africa)
SESP 6 Volcanism and Volcanic Eruptions
zhlédnutí 196Před 3 lety
SESP 6 Volcanism and Volcanic Eruptions
SESP 5 The Rock Cycle and Plate tectonics
zhlédnutí 209Před 3 lety
SESP 5 The Rock Cycle and Plate tectonics
SESP 1 Rocks Minerals and Rock Composition
zhlédnutí 212Před 3 lety
SESP 1 Rocks Minerals and Rock Composition
To my knowledge Stereonet 11 doesn't allow this. What I normally do is exporting the stereonet as a PDF, import that PDF into Adobe Illustrator (or any other graphics software) and add my annotations as needed.
Can you plot shear senses of lineation measurement, and if so how?
Thank you sir
super helpful, thanks!
so do your other videos, I automatically subscribed.
How to create a link in the pdf to open the attached pdf file
thank you for showing this option
What if the strike of the hinge line is unknown? How do we know it?
I’m not quite sure what the point of the question is. The hinge line doesn’t have a strike. It has a trend and a plunge, which is given by the position of the pole to the pi-plane. If the question refers to the strike of the axial surface, the answer would be that this direction must be determined in the field or from geological maps.
This is great man thanks
You're welcome
@@Geology_clipsmaybe you can explain why does the oblique subduction exist, it baffles my mind
@@iamthewalrus3655 Imagine an oceanic plate being pushed westwards by seafloor spreading, creating a westwards movement vector. If this plate is subducted underneath a stationary continent with a north-south continental margin, the subduction will be frontal (dip-slip). If the continental margin is oriented in any other direction (NE-SW, NNW-SSE, etc.) the subduction will be oblique to the continental margin. If the continental plate is non-stationary (most are), it's a bit more complicated. In principle, the magnitude and direction of the continental and oceanic plates' movement vectors and the orientation of the overriding plate's margin will determine whether the subduction is frontal (dip-slip, oblique, or whether there is a strike-slip movement along the plate margin (e.g. San Andreas Fault). I hope that helps.
Your explanation style is superb and easy to digest.
Thank you Sir.
Welcome!
Finally New lecture series come.😊 Thank you Sir.
Brilliant
How is your pi plane 307, 71? 307, 71 will dip in the NE direction.
All orientations are given as dip azimuth and dip angles (Clar readings).
I understand this. However, even after adding 90 to the great circle strike value on my stereonet then it plotting it as a separate line, it still does not match the best cylindrical fit. Why could this be the case?
I can't thank you enough; I keep revisiting these videos. And every time I do, I learn something new. I am a mineral exploration geologist. I am rebuilding my concepts and applying them in the field.
good
Hey mate, can you use the axial plane finder to determine the strike of the axial surface? is this also any information on using this for refolded folds?
Hello, just wondering how you got the number 304 for the strike of the actual surface at 14:44?
The strike of the axial surface must be obtained from field observation or from geological maps. It cannot be determined graphically using the stereonet.
@@Geology_clipsHello, can you please provide some guidance how to do that? Did you maybe refer to it in another video?
On a geological map you might see the typical lobes of fold closures where layers bend around the hinge and curve into the direction of the opposite limb. A line perpendicular to the folded layer in the hinge, and parallel to the limbs, is the best guess for the strike direction of the axial surface. If you are in the field try and find a view point in which you can see onto the pi-plane of the fold 9view direction parallel to the hinge and the axial surface). Then you can take a compass bearing and obtain a reasonably accurate estimate of the AS strike. In such situations you also can align your compass with the orientation of the AS and get a good estimate of its orientation. If you are lucky and the there is an axial plane cleavage developed, you can measure the AS directly, but take care to do this always in the centre of the fold hinge. @@nils6097
@@Geology_clips First of all, many thanks for the quick and comprehensive reply. I finally got what you meant. I hope you have a nice day.
thank you for this video. I had no idea it was hidden under the "comment" section
Thank you so much for this!
This channel is a haven for understanding structural geology , thanku for your efforts sir ❤️
Excellent explanation, thank you!❤
That's exactly what I needed from my google request how to add links to attached files in pdf file. Thank you so much!
Thanks! I had trouble finding the paperclip graphic. This was quite helpful!
How do you ploy pi-plane on stereonet?
That's explained at 10 min 30 sec to 12 min in the video.
Hi, when plotting the great circle to the bedding poles, it generates many different great circles rather than 1 do you know why
The surface of limbs of natural folds is always uneven and therefore compass readings show some variation for each limb. This results in some scattering of great circles or poles to planes. Average orientations of the limbs are therefore used to construct representative hinge line orientations and axial surfaces.
Very good! 👏👏👏
I need a reference to read. pdf, please.
Deer, Howie, Zussman, 2013. Introduction to Rock Forming Minerals.
Thank you, good explanation.
Thanks Sir.
Hi there, Where or how did you get the strike of the Axial Surface?
From field observation or from geological maps.
@@Geology_clips What is meant by the strike of the axial surface? I have lots of strike and dip data of the ascending limbs of an anticline, which i'm plotting on stereonet, how do I get the strike of the axial surface?
@@karlcarmody9935 For the geometric analysis you need data from both limbs . The axial surface ideally can be measured or estimated in the hinge zone. Otherwise fold closures of the fold itself or other folds nearby should be visible on geological maps. The best estimate for the strike of the axial surface one can get in such cases is by connecting the hinges of different layers on the map.
Any book you can recommend for structural geology???
A nice introductory text would be Rey's book: www.researchgate.net/publication/299135987_Introduction_to_Structural_Geology
Very informative video regarding fold analysis in steronet projection. Dear sir please upload more video regarding clasical structural analysis. Regards
Great intro !! Thanks
so great....................
Thank you for posting this. Very helpful. ONly lecture style introduction I could find.
Very very intressting
Excellent lecture. Thank you very much.
Sir ,thank you so much for this valuable video .The way you are teaching is best and cleared many things ☺️
Welcome back
i have one doubt sir can you explain
Thank you..we at Alexandria University, Egypt 🇪🇬 benefit from this scientific material.. never stop 💕
Thnku for such n amaizing explanation.
So so interesting! Thenk you
Super and simple
Thank you ♥️... You deserve more and your channel is really so underrated 🙂♥️♥️
Thank you so much 😀
Thank you ♥️✨
Very much interesting
Which is the company that created this software?
This is from Rick Allmendinger's software collection : www.rickallmendinger.net/
Very nice lecture!! Thanks a lot!! I was wondering to understand the decompression melt, I was reading from Earth a portrait of a planet by Stephen Marshak. The way you elaborated in this lecture is great!! Thanks again!!
Glad it was helpful!
Great lecture. I had a hard time understanding structural geology. You make sense. Hope you will keep posting.
Glad it was helpful!