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I REALLY APPRECIATE how you recognize stumbling blocks for learners: you immediately pointed out how unconformities are Erosional based and different than intrusive features. If you hadn’t noted that right up front, I am sure I would have been totally confused through the whole lecture stuck on “what about the dikes? Aren’t they unconformities?” I needed a million teachers like you and I would be a better thinker in life. THANK YOU
Thanks Shawn. Big smiles throughout; ties the concepts together well. It starts with time and pressure and ends with someone asking "what are the rocks telling us?"
Great processing through real world problems, like text book information, but real events have much more information to work with and I think lots of field work is necessary to get through these onion layers. Ty Shawn.
Thank you for creating these puzzles. It was great fun to try and solve the mysteries of those rock layers. I got almost all of them right, just overlooked a few details in the first one. I've learned a lot since episode 1.
Really enjoy being able to sit in your classroom work, thanks! This geologic puzzle looks like it will be fun. Your teaching has really helped me understand some of the damage Helene wrought as well.
Thank you, Shawn. Although I enjoyed it I have to admit I got totally lost at points but took each diagram and followed your way of breaking things down. I guess I need to take this sort of thing more slowly. I'll go back to this in a few days to see if it has embedded itself in my brain a little more clearly.
The contact metamorphism on top of the basalt in puzzle 1 is really interesting and something I never thought about before as a layman and casual enjoyer of geology. I figured the basalt layer was a surface lava flow, but then you mentioned the little lines representing observable metamorphic features at the contact point and it all clicked. I'm not sure how I hadn't realized that contact metamorphism existed and might be a tool used to date, or at least order, different rock formations. Thank you for your teachings!
Excellent! Using old Paint worked just fine...much more detail would have been confusing, I think. The puzzles are similar to your field diagrams: simple and easy-to-understand, but complex enough to require some brain power. Thanks for the reminder on the unconformities being erosional features...the only thing I missed on the first puzzle. You have a real knack for making complex topics easy and fun...thanks, Professor!😊
It was fun working through the relationships in these diagrams in a fashion similar to constructing a Harris matrix from an archaeological section drawing.
Respect , brother - 30 years of Montana work , you need to own two mules ! only way to travel when you investigate the more complicated then you can imagine sections .
😵💫 Just when I thought I had the answers! This was fun. I did better on the second one…and subsequent puzzles…I would’ve failed but overall I learned a lot and that’s what matters! The unconformities confuse me…except the angular one is easiest to see. So cool. Thank you!
Could be the same or a separate event - I'm imagining glaciation carving out then filling a valley, or filling in an existing river valley. Probably because the texture is evocative of glaciation gravel fill.
@@bluerendar2194 I live next (about 300 feet) to a dry riverbed that mostly flows when there is a flooding event upstream. The force of the water has washed large rocks down from the upper plateaus that are easily three feet wide if not larger so I don’t think the size of the gravels depicted in the diagram should be considered. When I first moved here 35 years ago the riverbed was ten feet deeper in places than it is now.
Yeah, was just reflecting on what I was thinking. But particle shape certainly does play a role in ID the formation method - and if we take the drawing way too seriously than we should, river bed sounds more reasonable actually given the rounded shapes.
Because G had contact metamorphosis it had to be baked by the basalt too. So I would assume there was a weak layer between P&G and/or P being much harder to break that had the basalt to spread/split that boundary.. I would assume there would be small fragments of G at the upper P-basalt interface and fragments of P in the lower basalt-G interface but in general it would follow the weakness.
@Kosmonooit Yes, because layer G shows evidence of being in contact with the basalt, so layer G had to exist before the basalt. It's tricky looking at it but I think it's designed that way to explain a concept.
Question about the last one.. Why is there no contact metamorphism in the sedimentary rocks from the andesite and basalt intrusions, am I correct in assuming that that is just because you first drew the andesite intrusion in the gneiss incliding the marks for contact metamorphosis, then added the sedimentsry rocks and just forgot to add the contact metamorphism lines at that point? Or is there a deeper seecret I don't understand? Love these GeoLogic puzzles..
Dear Professor, I would be delighted if you could make a video on the role of water in a supercritical state in the dissolution of minerals from rocks and their subsequent deposition. Thank you very much from Spain.
Shawn, my understanding is that we can make diamonds, coal, oil, opals etc. in the laboratory in a very short time. Maybe do an episode on why you think the earth did/does not make these goodies quickly. Observational/laboratory science tells us that geo-things are made quickly not over millions and billions of years. Thanks.
I'm really enjoying your lectures Shawn. Could the dioxide also have been anytime after j (& before faulting) in the first one. Cheers Joy Jimboomba, Australia
Thank you for sharing all of these episodes. I have been enjoying them! I do have a question about your first puzzle tho... I was assuming that T could be older than X (could go in either order), but you chose X first. Why? Is it because the amount of tilting is less than 90 degrees? Thanks!
In Geo Logic puzzle #1: 1) Could you have had X/F/J/S, diorite, fault, A/D/T, tilting, ...? It doesn't seem that there is anything constraining the deposition of A/D/T to coming before the diorite or the fault (but we know A/D/T came before tilt and erosion). 2) Is there anything constraining the tilting to before the diorite?
@shawnwillsey Another question about the last puzzle: On the left the layers AEPK are not folded and on the right (of the fault) they are folded. Doesn't that mean that the folding came after the fault?
The basics I did okay, like going oldest to youngest. I could do better with the rest. That was interesting. I like the puzzles, I just don't want super crazy puzzles.
Q: In the first scenario, could the Basalt have been deposited at an angle after the layers had already been tilted? Would there be any signs in the Basalt or surrounding layers that could tell us whether it was deposited flat, or at an angle? (e.g. compositional gravitational differentiation etc.) In the third scenario, with only the slice of information as shown, could the Basalt be as young as slightly older than deposit H - in my mind, having reached through W, but prior to H eroding so that is no longer visible? I suppose before coming to radiological or chemical dating methods, I would look along the features to see any evidence of or contrary to such, if the H feature at other places doesn't line up with the Basalt, or evidence of it weathering and being included within the H or other features.
I would also say it's possible with just this cross-section and no other information. It could be anything between younger than L but older than X and slightly older than H. We just don't see what happened in that erosional pocket.
Since T is rock (in the 1st one) and L (in the 2nd one), wouldn't that imply there were rocks (or weight) above it have compressed T and L into rock but are no longer there so were eroded away before the tilting and folding (unconformity) ?
Yep, but looking at just this location alone, it is hard to say what they could've been. Perhaps there are other locations that might show what existed, but quite possibly those layers have been entirely eroded away and no evidence of what they were like exist anymore.
For the first puzzle: What would the evidence look like for T having been the oldest rock? Could the diorite and the fault not have been anytime after J?
The orientation of the diorite slightly suggests the intrusion happened after tilting, but it still is possible otherwise without further evidence. I wouldn't rule out your suggestion, but it doesn't seem like the most likely scenario. Supposing that is the case, then since the tilt is after all depositional events before the unconformity, then the order must be all sed deposition -> tilting -> intrusion -> fault (since the fault cuts the diorite). Also, very good point on T! With such an extreme tilt, it's possible the folding created an inversion and the sedimentary ages could be T oldest and X youngest, even if that is not the most likely scenario. What additional evidence outside of the diagram might you look for to determine if that is the case?
Question about the 2nd puzzle: In the diagram it looks like the tops of the dikes as well as the top of the granite intrusion were eroded before the overlying layer of sediment was deposited. Aren't those spots nonconformities? Love this video btw!
Shallow intrusions often cool somewhat quickly, yielding an aphanitic or porphyritic texture that is associated with basalt rather than the visible, interlocking crystals (phaneritic texture) of gabbro.
Can['t see where the granite came from, would guess that it was hidden under your overlay -- keep in mind, we don't ALWAYS have to see your face, if we can hear you.
Please LIKE and SUBSCRIBE. I also appreciate your continual support of these geology education videos. To do so, click on the "Thanks" button just above (right of Download button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Or: www.buymeacoffee.com/shawnwillsey
Nice to see that even the teacher can make mistakes. That's a good lesson for all of us. Thanks for your honesty, Shawn.
I REALLY APPRECIATE how you recognize stumbling blocks for learners: you immediately pointed out how unconformities are Erosional based and different than intrusive features. If you hadn’t noted that right up front, I am sure I would have been totally confused through the whole lecture stuck on “what about the dikes? Aren’t they unconformities?” I needed a million teachers like you and I would be a better thinker in life. THANK YOU
Thanks Shawn. Big smiles throughout; ties the concepts together well. It starts with time and pressure and ends with someone asking "what are the rocks telling us?"
Shawn makes learning so much fun
Yes, we know it's fun because Shawn says so.
Wow! LOVED it! How fun and useful! Thank you for your wonderful channel! I enjoy it a lot!
Bedankt
Thanks!
Love these types of puzzles.
Thanks for all the hard work on these videos!
Oh, wonderful, another interesting lesson!! 🤗👍
Thank you professor! Very interactive and educational.
Tack!
Brilliant! I loved the puzzles, thanks for your excellent teaching
Thank you Shawn!
Oh man, this was such a great video, Shawn!! I could do these all day long!!
Great processing through real world problems, like text book information, but real events have much more information to work with and I think lots of field work is necessary to get through these onion layers. Ty Shawn.
Thank You Sir for your consistency
That was fun ❤️✌️👍
Also, this makes random roadcuts even more interesting.
Loved this vid! especially because I "won" in my guesses in most of the steps! Wheeee! Thanks Shawn
Those were fun puzzles. And helpful.
Brilliant and most importantly understood thank you for sharing
Excellent! Thanks for these geo-logic puzzles, Shawn! I did pretty good actually, and you're right, learning is fun! :)
This was very informative-Thank You Shawn
Thank you for creating these puzzles. It was great fun to try and solve the mysteries of those rock layers. I got almost all of them right, just overlooked a few details in the first one. I've learned a lot since episode 1.
Lots of fun! Thanks for doing this!
Really enjoy being able to sit in your classroom work, thanks! This geologic puzzle looks like it will be fun. Your teaching has really helped me understand some of the damage Helene wrought as well.
The obvious answer is always 42! lol 😊
Thank you Prof Willsey 🙏
Thank you, Shawn. Although I enjoyed it I have to admit I got totally lost at points but took each diagram and followed your way of breaking things down. I guess I need to take this sort of thing more slowly. I'll go back to this in a few days to see if it has embedded itself in my brain a little more clearly.
This is incredibly fun. Look forward to more of these
The contact metamorphism on top of the basalt in puzzle 1 is really interesting and something I never thought about before as a layman and casual enjoyer of geology. I figured the basalt layer was a surface lava flow, but then you mentioned the little lines representing observable metamorphic features at the contact point and it all clicked. I'm not sure how I hadn't realized that contact metamorphism existed and might be a tool used to date, or at least order, different rock formations. Thank you for your teachings!
Thanks Shawn! This series has been excellent.
I always come away from these at least somewhat understanding and happy I watched :)
Thank you, a fun way of learning. Greetings from your mexican 'student'.
Hola!
Thank you for the awesome class🧗
Excellent! Using old Paint worked just fine...much more detail would have been confusing, I think. The puzzles are similar to your field diagrams: simple and easy-to-understand, but complex enough to require some brain power. Thanks for the reminder on the unconformities being erosional features...the only thing I missed on the first puzzle. You have a real knack for making complex topics easy and fun...thanks, Professor!😊
This was great, thanks!
It was fun working through the relationships in these diagrams in a fashion similar to constructing a Harris matrix from an archaeological section drawing.
thanks Shawn
Great, love it, thanks
These were fun. I got most of them but need to study nonconformities more
These are fun!
You might try to persuade who are left of Supertramp to compose a geo-logical song! 😊
Respect , brother - 30 years of Montana work , you need to own two mules ! only way to travel when you investigate the more complicated then you can imagine sections .
70%, getting better thank you.
😵💫 Just when I thought I had the answers! This was fun. I did better on the second one…and subsequent puzzles…I would’ve failed but overall I learned a lot and that’s what matters! The unconformities confuse me…except the angular one is easiest to see. So cool. Thank you!
more please!
Are V & H an erosion of W event or the deposited material? Is the filling in a separate event?
Could be the same or a separate event - I'm imagining glaciation carving out then filling a valley, or filling in an existing river valley. Probably because the texture is evocative of glaciation gravel fill.
@@bluerendar2194 I live next (about 300 feet) to a dry riverbed that mostly flows when there is a flooding event upstream. The force of the water has washed large rocks down from the upper plateaus that are easily three feet wide if not larger so I don’t think the size of the gravels depicted in the diagram should be considered. When I first moved here 35 years ago the riverbed was ten feet deeper in places than it is now.
Yeah, was just reflecting on what I was thinking. But particle shape certainly does play a role in ID the formation method - and if we take the drawing way too seriously than we should, river bed sounds more reasonable actually given the rounded shapes.
1) Wouldn't the Basalt layer be a surface outflow from that pipe on to layer P then G a sedimentary later later?
Because G had contact metamorphosis it had to be baked by the basalt too. So I would assume there was a weak layer between P&G and/or P being much harder to break that had the basalt to spread/split that boundary.. I would assume there would be small fragments of G at the upper P-basalt interface and fragments of P in the lower basalt-G interface but in general it would follow the weakness.
@@benibear2995 So the basalt layer infused between P and G?
@Kosmonooit Yes, because layer G shows evidence of being in contact with the basalt, so layer G had to exist before the basalt. It's tricky looking at it but I think it's designed that way to explain a concept.
I did pretty good. Really good followup for the unconformity unit..actually put it to use.
Question about the last one.. Why is there no contact metamorphism in the sedimentary rocks from the andesite and basalt intrusions, am I correct in assuming that that is just because you first drew the andesite intrusion in the gneiss incliding the marks for contact metamorphosis, then added the sedimentsry rocks and just forgot to add the contact metamorphism lines at that point? Or is there a deeper seecret I don't understand? Love these GeoLogic puzzles..
My mistake. I forgot to draw the little tick marks on the rest of the andesite dike and the basalt dike. Ugh. good intentions.
I used to wonder why archaeology and geology shared a building at the University of Edinburgh but it all makes sense now
Dear Professor, I would be delighted if you could make a video on the role of water in a supercritical state in the dissolution of minerals from rocks and their subsequent deposition. Thank you very much from Spain.
Yes, I can solve it. It is a simplified geologic cross section. I am a geophysicist.😊
Shawn, my understanding is that we can make diamonds, coal, oil, opals etc. in the laboratory in a very short time. Maybe do an episode on why you think the earth did/does not make these goodies quickly. Observational/laboratory science tells us that geo-things are made quickly not over millions and billions of years. Thanks.
I'm really enjoying your lectures Shawn. Could the dioxide also have been anytime after j (& before faulting) in the first one.
Cheers
Joy
Jimboomba, Australia
Further question Shawn, would not the lower boundaries of V and H also be angular unconformities?
Thanks again.
Joy from Aus.
Thank you for sharing all of these episodes. I have been enjoying them! I do have a question about your first puzzle tho... I was assuming that T could be older than X (could go in either order), but you chose X first. Why? Is it because the amount of tilting is less than 90 degrees? Thanks!
In Geo Logic puzzle #1:
1) Could you have had X/F/J/S, diorite, fault, A/D/T, tilting, ...? It doesn't seem that there is anything constraining the deposition of A/D/T to coming before the diorite or the fault (but we know A/D/T came before tilt and erosion).
2) Is there anything constraining the tilting to before the diorite?
@shawnwillsey
Another question about the last puzzle:
On the left the layers AEPK are not folded and on the right (of the fault) they are folded. Doesn't that mean that the folding came after the fault?
The basics I did okay, like going oldest to youngest. I could do better with the rest. That was interesting. I like the puzzles, I just don't want super crazy puzzles.
Ok, question on the third puzzle. Wouldn’t the fault come BEFORE the folding since the parts to the right are folded but the left is still flat?
I'd say it's ambiguous as the fault is exactly perpendicular to the fold.
Holy moley!
Q: In the first scenario, could the Basalt have been deposited at an angle after the layers had already been tilted? Would there be any signs in the Basalt or surrounding layers that could tell us whether it was deposited flat, or at an angle? (e.g. compositional gravitational differentiation etc.)
In the third scenario, with only the slice of information as shown, could the Basalt be as young as slightly older than deposit H - in my mind, having reached through W, but prior to H eroding so that is no longer visible?
I suppose before coming to radiological or chemical dating methods, I would look along the features to see any evidence of or contrary to such, if the H feature at other places doesn't line up with the Basalt, or evidence of it weathering and being included within the H or other features.
I would also say it's possible with just this cross-section and no other information. It could be anything between younger than L but older than X and slightly older than H. We just don't see what happened in that erosional pocket.
Shouldn't there be contact metamorphism on the andesite and basalt thru the sandstone layers?
Yep. I forgot to include those when I made the diagram. Doh!
I think it might be assumed thru the sedimentary layers, but is needed for sequence between the igneous layers?
These exercises were a lot of fun!
in #1 puzzle, how do you know the tilting of x-t happened before the diorite intrusion?
Could be either/or.
@@shawnwillsey got it, thanks!
Hello Shawn.
FUN! 👍
On the last problem your insert covered the word "granite" so I called the red blob.
Why isn’t the basalt *before* g? It looks like g b q went on top of the basalt and g b q on top of the basalt.
Since T is rock (in the 1st one) and L (in the 2nd one), wouldn't that imply there were rocks (or weight) above it have compressed T and L into rock but are no longer there so were eroded away before the tilting and folding (unconformity) ?
Yep, but looking at just this location alone, it is hard to say what they could've been. Perhaps there are other locations that might show what existed, but quite possibly those layers have been entirely eroded away and no evidence of what they were like exist anymore.
For the first puzzle: What would the evidence look like for T having been the oldest rock? Could the diorite and the fault not have been anytime after J?
The orientation of the diorite slightly suggests the intrusion happened after tilting, but it still is possible otherwise without further evidence. I wouldn't rule out your suggestion, but it doesn't seem like the most likely scenario.
Supposing that is the case, then since the tilt is after all depositional events before the unconformity, then the order must be all sed deposition -> tilting -> intrusion -> fault (since the fault cuts the diorite).
Also, very good point on T! With such an extreme tilt, it's possible the folding created an inversion and the sedimentary ages could be T oldest and X youngest, even if that is not the most likely scenario. What additional evidence outside of the diagram might you look for to determine if that is the case?
Question about the 2nd puzzle: In the diagram it looks like the tops of the dikes as well as the top of the granite intrusion were eroded before the overlying layer of sediment was deposited. Aren't those spots nonconformities? Love this video btw!
Yes, these surfaces would be nonconformities where the igneous rocks lie below.
in the first one, how can you be sure te diorite is younger than T, D, A or S?
Good point. Diorite intrusion could be before tilting. I should have added a dike coming off the intrusion that cut through T.
@@shawnwillsey
Thanks for your answer!
With these geo-logic puzzles, I wonder if even the angels had some brain hurt in figuring out all the complexities that happened !!!!
whew...no beach balls on that test so I passed 😝
Like any other puzzle , it's the missing pieces that cause the most drama .
4 unconfomities not 3, you have mised the two erosional vallies
I thought basalt that happened underground was gabbro
Shallow intrusions often cool somewhat quickly, yielding an aphanitic or porphyritic texture that is associated with basalt rather than the visible, interlocking crystals (phaneritic texture) of gabbro.
Oops that was not easy for me. I should repeat the former lessons.. 😊😮
Can['t see where the granite came from, would guess that it was hidden under your overlay -- keep in mind, we don't ALWAYS have to see your face, if we can hear you.
Whenever there is a ? in the title...I'll answer with No.
Move your picture
I give myself a C plus. So disappointing.
Thanks!
Thanks!